From f45fedbec21f12b8a5b8ea6bfa18410327849261 Mon Sep 17 00:00:00 2001
From: Neil MacIntosh <neilmac@microsoft.com>
Date: Thu, 15 Oct 2015 14:29:35 -0700
Subject: [PATCH 01/43] Partway through removing configurable SizeType.

---
 include/array_view.h       | 786 +++++++++++++++++--------------------
 include/string_view.h      |  39 +-
 tests/array_view_tests.cpp |  12 +-
 tests/bounds_tests.cpp     |  36 +-
 4 files changed, 411 insertions(+), 462 deletions(-)

diff --git a/include/array_view.h b/include/array_view.h
index 046cbf8..1178e43 100644
--- a/include/array_view.h
+++ b/include/array_view.h
@@ -67,43 +67,38 @@ namespace gsl {
 */
 namespace details
 {
-	template <typename SizeType>
-	struct SizeTypeTraits
-	{
-		static const size_t max_value = std::is_signed<SizeType>::value ? static_cast<typename std::make_unsigned<SizeType>::type>(-1) / 2 : static_cast<SizeType>(-1);
-	};
-
-
-	template <typename ConcreteType, typename ValueType, size_t Rank>
+	template <typename ConcreteType, size_t Rank>
 	class coordinate_facade
 	{
-		static_assert(std::is_integral<ValueType>::value
-			&& sizeof(ValueType) <= sizeof(size_t), "ValueType must be an integral type!");
 		static_assert(Rank > 0, "Rank must be greater than 0!");
 
-		template <typename OtherConcreteType, typename OtherValueType, size_t OtherRank>
+		template <typename OtherConcreteType, size_t OtherRank>
 		friend class coordinate_facade;
 	public:
-		using reference       = ValueType&;
-		using const_reference = const ValueType&;
-		using value_type      = ValueType;
+		using reference       = std::add_lvalue_reference_t<std::ptrdiff_t>;
+		using const_reference = std::add_const_t<reference>;
+		using value_type      = std::ptrdiff_t;
 		static const size_t rank = Rank;
+
 		constexpr coordinate_facade() noexcept
 		{
 			static_assert(std::is_base_of<coordinate_facade, ConcreteType>::value, "ConcreteType must be derived from coordinate_facade.");
 		}
+
 		constexpr coordinate_facade(const value_type(&values)[rank]) noexcept
 		{
 			static_assert(std::is_base_of<coordinate_facade, ConcreteType>::value, "ConcreteType must be derived from coordinate_facade.");
 			for (size_t i = 0; i < rank; ++i)
 				elems[i] = values[i];
 		}
+
 		constexpr coordinate_facade(value_type e0) noexcept
 		{
 			static_assert(std::is_base_of<coordinate_facade, ConcreteType>::value, "ConcreteType must be derived from coordinate_facade.");
 			static_assert(rank == 1, "This constructor can only be used with rank == 1.");
 			elems[0] = e0;
 		}
+
 		// Preconditions: il.size() == rank
 		constexpr coordinate_facade(std::initializer_list<value_type> il)
 		{
@@ -117,15 +112,13 @@ namespace details
 
 		constexpr coordinate_facade(const coordinate_facade & other) = default;
 
-		template <typename OtherConcreteType, typename OtherValueType>
-		constexpr coordinate_facade(const coordinate_facade<OtherConcreteType, OtherValueType, Rank> & other)
+		template <typename OtherConcreteType>
+		constexpr coordinate_facade(const coordinate_facade<OtherConcreteType, Rank>& other)
 		{
-			for (size_t i = 0; i < rank; ++i)
-			{
-				fail_fast_assert(static_cast<size_t>(other.elems[i]) <= SizeTypeTraits<value_type>::max_value);
-				elems[i] = static_cast<value_type>(other.elems[i]);
-			}
+    		for (size_t i = 0; i < rank; ++i)
+				elems[i] = other.elems[i];
 		}
+
 	protected:
 		coordinate_facade& operator=(const coordinate_facade& rhs) = default;
 		// Preconditions: component_idx < rank
@@ -267,12 +260,12 @@ namespace details
 	};
 }
 
-template <size_t Rank, typename ValueType = size_t>
-class index : private details::coordinate_facade<index<Rank, ValueType>, ValueType, Rank>
+template <size_t Rank>
+class index : private details::coordinate_facade<index<Rank>, Rank>
 {
-	using Base = details::coordinate_facade<index<Rank, ValueType>, ValueType, Rank>;
+	using Base = details::coordinate_facade<index<Rank>, Rank>;
 	friend Base;
-	template <size_t OtherRank, typename OtherValueType>
+	template <size_t OtherRank>
 	friend class index;
 public:
 	using Base::rank;
@@ -286,11 +279,7 @@ public:
 
 	constexpr index(const index &) = default;
 
-	template <typename OtherValueType>
-	constexpr index(const index<Rank, OtherValueType> &other) : Base(other)
-	{
-	}	
-	constexpr static index shift_left(const index<rank+1, value_type>& other) noexcept
+	constexpr static index shift_left(const index<rank+1>& other) noexcept
 	{
 			value_type (&arr)[rank] = (value_type(&)[rank])(*(other.elems + 1));
 			return index(arr);
@@ -311,28 +300,26 @@ public:
 	using Base::operator/=;
 };
 
-template <typename ValueType>
-class index<1, ValueType>
+template<>
+class index<1>
 {
-	template <size_t, typename OtherValueType>
-	friend class index;
 public:
 	static const size_t rank = 1;
-	using reference = ValueType&;
-	using const_reference = const ValueType&;
-	using size_type = ValueType;
-	using value_type = ValueType;
+    using size_type = std::ptrdiff_t;
+    using value_type = std::ptrdiff_t;
+    using reference = std::add_lvalue_reference_t<std::ptrdiff_t>;
+    using const_reference = const std::ptrdiff_t&;//std::add_const_t<std::add_lvalue_reference_t<std::ptrdiff_t>>;
 	
-	constexpr index() noexcept : value(0)
-	{
-	}
+    constexpr index() noexcept : value(0)
+    {}
+
 	constexpr index(value_type e0) noexcept : value(e0)
-	{
-	}
-	constexpr index(const value_type(&values)[1]) noexcept : index(values[0]) 
-	{
-	}
-	// Preconditions: il.size() == rank
+	{}
+
+    constexpr index(const value_type(&values)[1]) noexcept : index(values[0])
+    {}
+
+    // Preconditions: il.size() == rank
 	constexpr index(std::initializer_list<value_type> il)
 	{
 		fail_fast_assert(il.size() == rank, "Size of the initializer list must match the rank of the array");
@@ -341,288 +328,239 @@ public:
 
 	constexpr index(const index &) = default;
 
-	template <typename OtherValueType>
-	constexpr index(const index<1, OtherValueType> & other)
-	{
-		fail_fast_assert(other.value <= details::SizeTypeTraits<ValueType>::max_value);
-		value = static_cast<ValueType>(other.value);
-	}
-
-	constexpr static index shift_left(const index<rank + 1, value_type>& other) noexcept
+	constexpr static index shift_left(const index<rank + 1>& other) noexcept
 	{
 		return other.elems[1];
 	}
+
 	// Preconditions: component_idx < rank
 	constexpr reference operator[](size_type component_idx) noexcept
 	{
 		fail_fast_assert(component_idx == 0, "Component index must be less than rank");
-		(void)(component_idx);
 		return value;
 	}
+
 	// Preconditions: component_idx < rank
 	constexpr const_reference operator[](size_type component_idx) const noexcept
 	{
 		fail_fast_assert(component_idx == 0, "Component index must be less than rank");
-		(void)(component_idx);
 		return value;
 	}
+
 	constexpr bool operator==(const index& rhs) const noexcept
 	{
 		return value == rhs.value;
 	}
+
 	constexpr bool operator!=(const index& rhs) const noexcept
 	{
 		return !(*this == rhs);
 	}
-	constexpr index operator+() const noexcept
+	
+    constexpr index operator+() const noexcept
 	{
 		return *this;
 	}
-	constexpr index operator-() const noexcept
+	
+    constexpr index operator-() const noexcept
 	{
 		return index(-value);
 	}
-	constexpr index operator+(const index& rhs) const noexcept
+	
+    constexpr index operator+(const index& rhs) const noexcept
 	{
 		return index(value + rhs.value);
 	}
-	constexpr index operator-(const index& rhs) const noexcept
+	
+    constexpr index operator-(const index& rhs) const noexcept
 	{
 		return index(value - rhs.value);
 	}
-	constexpr index& operator+=(const index& rhs) noexcept
+	
+    constexpr index& operator+=(const index& rhs) noexcept
 	{
 		value += rhs.value;
 		return *this;
 	}
-	constexpr index& operator-=(const index& rhs) noexcept
+	
+    constexpr index& operator-=(const index& rhs) noexcept
 	{
 		value -= rhs.value;
 		return *this;
 	}
-	constexpr index& operator++() noexcept
+	
+    constexpr index& operator++() noexcept
 	{
 		++value;
 		return *this;
 	}
-	constexpr index operator++(int) noexcept
+	
+    constexpr index operator++(int) noexcept
 	{
 		index ret = *this;
 		++(*this);
 		return ret;
 	}
-	constexpr index& operator--() noexcept
+	
+    constexpr index& operator--() noexcept
 	{
 		--value;
 		return *this;
 	}
-	constexpr index operator--(int) noexcept
+	
+    constexpr index operator--(int) noexcept
 	{
 		index ret = *this;
 		--(*this);
 		return ret;
 	}
-	constexpr index operator*(value_type v) const noexcept
+	
+    constexpr index operator*(value_type v) const noexcept
 	{
 		return index(value * v);
 	}
-	constexpr index operator/(value_type v) const noexcept
+	
+    constexpr index operator/(value_type v) const noexcept
 	{
 		return index(value / v);
 	}
-	constexpr index& operator*=(value_type v) noexcept
+	
+    constexpr index& operator*=(value_type v) noexcept
 	{
 		value *= v;
 		return *this;
 	}
-	constexpr index& operator/=(value_type v) noexcept
+	
+    constexpr index& operator/=(value_type v) noexcept
 	{
 		value /= v;
 		return *this;
 	}
-	friend constexpr index operator*(value_type v, const index& rhs) noexcept
+	
+    friend constexpr index operator*(value_type v, const index& rhs) noexcept
 	{
 		return index(rhs * v);
 	}
+
 private:
 	value_type value;
 };
 
-#ifndef _MSC_VER
-
-struct static_bounds_dynamic_range_t
-{
-	template <typename T, typename Dummy = std::enable_if_t<std::is_integral<T>::value>>
-	constexpr operator T() const noexcept
-	{
-		return static_cast<T>(-1);
-	}
-
-	template <typename T, typename Dummy = std::enable_if_t<std::is_integral<T>::value>>
-	constexpr bool operator ==(T other) const noexcept
-	{
-		return static_cast<T>(-1) == other;
-	}
-
-	template <typename T, typename Dummy = std::enable_if_t<std::is_integral<T>::value>>
-	constexpr bool operator !=(T other) const noexcept
-	{
-		return static_cast<T>(-1) != other;
-	}
-
-};
-
-template <typename T, typename Dummy = std::enable_if_t<std::is_integral<T>::value>>
-constexpr bool operator ==(T left, static_bounds_dynamic_range_t right) noexcept
-{
-	return right == left;
-}
-
-template <typename T, typename Dummy = std::enable_if_t<std::is_integral<T>::value>>
-constexpr bool operator !=(T left, static_bounds_dynamic_range_t right) noexcept
-{
-	return right != left;
-}
-
-constexpr static_bounds_dynamic_range_t dynamic_range{};
-#else
-const char dynamic_range = -1;
-#endif
+const std::ptrdiff_t dynamic_range = -1;
 
 struct generalized_mapping_tag {};
 struct contiguous_mapping_tag : generalized_mapping_tag {};
 
 namespace details
 {
-	template <typename SizeType, SizeType Fact1, SizeType Fact2, SizeType ConstBound>
-	struct StaticSizeHelperImpl
-	{
-		static_assert(static_cast<size_t>(Fact1) * static_cast<size_t>(Fact2) <= SizeTypeTraits<SizeType>::max_value, "Value out of the range of SizeType");
-		static const SizeType value = Fact1 * Fact2;
-	};
 
-	template <typename SizeType, SizeType Fact1, SizeType ConstBound>
-	struct StaticSizeHelperImpl<SizeType, Fact1, ConstBound, ConstBound>
-	{
-		static const SizeType value = ConstBound;
-	};
-
-	template <typename SizeType, SizeType Fact2, SizeType ConstBound>
-	struct StaticSizeHelperImpl<SizeType, ConstBound, Fact2, ConstBound>
-	{
-		static const SizeType value = ConstBound;
-	};
-
-	template <typename SizeType, SizeType ConstBound>
-	struct StaticSizeHelperImpl<SizeType, ConstBound, ConstBound, ConstBound>
-	{
-		static const SizeType value = static_cast<SizeType>(ConstBound);
-	};
-
-	template <typename SizeType, SizeType Fact1, SizeType Fact2>
-	struct StaticSizeHelper
-	{
-		static const SizeType value = StaticSizeHelperImpl<SizeType, static_cast<SizeType>(Fact1), static_cast<SizeType>(Fact2), static_cast<SizeType>(dynamic_range)>::value;
-	};
-
-
-	template <size_t Left, size_t Right>
+	template <std::ptrdiff_t Left, std::ptrdiff_t Right>
 	struct LessThan
 	{
 		static const bool value = Left < Right;
 	};
 
-	template <typename SizeType, size_t... Ranges>
+	template <std::ptrdiff_t... Ranges>
 	struct BoundsRanges {
-		static const size_t Depth = 0;
-		static const size_t DynamicNum = 0;
-		static const SizeType CurrentRange = 1;
-		static const SizeType TotalSize = 1;
+        using size_type = std::ptrdiff_t;
+		static const size_type Depth = 0;
+		static const size_type DynamicNum = 0;
+		static const size_type CurrentRange = 1;
+		static const size_type TotalSize = 1;
 
-		BoundsRanges (const BoundsRanges &) = default;
-
-		// TODO : following signature is for work around VS bug
-		template <typename OtherType>
-		BoundsRanges (const OtherType &, bool /* firstLevel */) {}
-		BoundsRanges(const SizeType * const) { }
+		BoundsRanges (const BoundsRanges&) = default;
+		BoundsRanges(const size_type* const) { }
 		BoundsRanges() = default;
 
 
 		template <typename T, size_t Dim>
-		void serialize(T &) const {
-		}
+		void serialize(T&) const
+        {}
+
 		template <typename T, size_t Dim>
-		SizeType linearize(const T &) const { 
-			return 0;
-		}
-		template <typename T, size_t Dim>
-		ptrdiff_t contains(const T &) const {
+		size_type linearize(const T&) const
+        { 
 			return 0;
 		}
 
-		size_t totalSize() const noexcept {
+		template <typename T, size_t Dim>
+		bool contains(const T&) const
+        {
+			return 0;
+		}
+
+		size_type totalSize() const noexcept
+        {
 			return TotalSize;
 		}
 
-		bool operator == (const BoundsRanges &) const noexcept
+		bool operator==(const BoundsRanges&) const noexcept
 		{
 			return true;
 		}
 	};
 
-	template <typename SizeType, size_t... RestRanges>
-	struct BoundsRanges <SizeType, dynamic_range, RestRanges...> : BoundsRanges<SizeType, RestRanges...>{
-		using Base = BoundsRanges <SizeType, RestRanges... >;
+	template <std::ptrdiff_t... RestRanges>
+	struct BoundsRanges <dynamic_range, RestRanges...> : BoundsRanges<RestRanges...>{
+		using Base = BoundsRanges <RestRanges... >;
+        using size_type = Base::size_type;
 		static const size_t Depth = Base::Depth + 1;
 		static const size_t DynamicNum = Base::DynamicNum + 1;
-		static const SizeType CurrentRange = dynamic_range;
-		static const SizeType TotalSize = dynamic_range;
-		const SizeType m_bound;
+		static const size_type CurrentRange = dynamic_range;
+		static const size_type TotalSize = dynamic_range;
+		const size_type m_bound;
 
-		BoundsRanges (const BoundsRanges &) = default;
-		BoundsRanges(const SizeType * const arr) : Base(arr + 1), m_bound(static_cast<SizeType>(*arr * this->Base::totalSize()))
+		BoundsRanges (const BoundsRanges&) = default;
+		
+        BoundsRanges(const size_type* const arr) : Base(arr + 1), m_bound(*arr * this->Base::totalSize())
 		{
 			fail_fast_assert(0 <= *arr);
-			fail_fast_assert(*arr * this->Base::totalSize() <= details::SizeTypeTraits<SizeType>::max_value);
 		}
+
 		BoundsRanges() : m_bound(0) {}
 
-		template <typename OtherSizeType, size_t OtherRange, size_t... RestOtherRanges>
-		BoundsRanges(const BoundsRanges<OtherSizeType, OtherRange, RestOtherRanges...> &other, bool /* firstLevel */ = true) :
-			Base(static_cast<const BoundsRanges<OtherSizeType, RestOtherRanges...>&>(other), false), m_bound (static_cast<SizeType>(other.totalSize()))
-		{
-		}
+		template <std::ptrdiff_t OtherRange, std::ptrdiff_t... RestOtherRanges>
+        BoundsRanges(const BoundsRanges<OtherRange, RestOtherRanges...>& other, bool /* firstLevel */ = true) :
+            Base(static_cast<const BoundsRanges<RestOtherRanges...>&>(other), false), m_bound(other.totalSize())
+        {}
 
 		template <typename T, size_t Dim = 0>
-		void serialize(T & arr) const {
+		void serialize(T& arr) const
+        {
 			arr[Dim] = elementNum();
 			this->Base::template serialize<T, Dim + 1>(arr);
 		}
+
 		template <typename T, size_t Dim = 0>
-		SizeType linearize(const T & arr) const { 
-			const size_t index = this->Base::totalSize() * arr[Dim];
-			fail_fast_assert(index < static_cast<size_t>(m_bound));
-			return static_cast<SizeType>(index) + this->Base::template linearize<T, Dim + 1>(arr);
+		size_type linearize(const T& arr) const
+        { 
+			const size_type index = this->Base::totalSize() * arr[Dim];
+			fail_fast_assert(index < m_bound);
+			return index + this->Base::template linearize<T, Dim + 1>(arr);
 		}
 		
 		template <typename T, size_t Dim = 0>
-		ptrdiff_t contains(const T & arr) const {
+		size_type contains(const T & arr) const
+        {
 			const ptrdiff_t last = this->Base::template contains<T, Dim + 1>(arr);
 			if (last == -1)
 				return -1;
 			const ptrdiff_t cur = this->Base::totalSize() * arr[Dim];
-			return static_cast<size_t>(cur) < static_cast<size_t>(m_bound) ? cur + last : -1;
+			return cur < m_bound ? cur + last : -1;
 		}
 		
-		size_t totalSize() const noexcept {
+		size_type totalSize() const noexcept
+        {
 			return m_bound;
 		}
 		
-		SizeType elementNum() const noexcept {
-			return static_cast<SizeType>(totalSize() / this->Base::totalSize());
+        size_type elementNum() const noexcept
+        {
+			return totalSize() / this->Base::totalSize();
 		}
 		
-		SizeType elementNum(size_t dim) const noexcept{
+        size_type elementNum(size_t dim) const noexcept
+        {
 			if (dim > 0)
 				return this->Base::elementNum(dim - 1);
 			else
@@ -631,67 +569,75 @@ namespace details
 
 		bool operator == (const BoundsRanges & rhs) const noexcept
 		{
-			return m_bound == rhs.m_bound && static_cast<const Base &>(*this) == static_cast<const Base &>(rhs);
+			return m_bound == rhs.m_bound && static_cast<const Base&>(*this) == static_cast<const Base&>(rhs);
 		}
 	};
 
-	template <typename SizeType, size_t CurRange, size_t... RestRanges>
-	struct BoundsRanges <SizeType, CurRange, RestRanges...> : BoundsRanges<SizeType, RestRanges...>{
-		using Base = BoundsRanges <SizeType, RestRanges... >;
+	template <std::ptrdiff_t CurRange, std::ptrdiff_t... RestRanges>
+	struct BoundsRanges <CurRange, RestRanges...> : BoundsRanges<RestRanges...>
+    {
+		using Base = BoundsRanges <RestRanges... >;
+        using size_type = Base::size_type;
 		static const size_t Depth = Base::Depth + 1;
 		static const size_t DynamicNum = Base::DynamicNum;
-		static const SizeType CurrentRange = static_cast<SizeType>(CurRange);
-		static const SizeType TotalSize = StaticSizeHelper<SizeType, Base::TotalSize, CurrentRange>::value;
-		static_assert (CurRange <= SizeTypeTraits<SizeType>::max_value, "CurRange must be smaller than SizeType limits");
+		static const size_type CurrentRange = CurRange;
+		static const size_type TotalSize = CurrentRange;
+		static_assert (CurRange <= PTRDIFF_MAX, "CurRange must be smaller than std::ptrdiff_t limits");
 
-		BoundsRanges (const BoundsRanges &) = default;
-		BoundsRanges(const SizeType * const arr) : Base(arr) { }
+		BoundsRanges (const BoundsRanges&) = default;
+		BoundsRanges(const size_type* const arr) : Base(arr) { }
 		BoundsRanges() = default;
 
-		template <typename OtherSizeType, size_t OtherRange, size_t... RestOtherRanges>
-		BoundsRanges(const BoundsRanges<OtherSizeType, OtherRange, RestOtherRanges...> &other, bool firstLevel = true) : Base(static_cast<const BoundsRanges<OtherSizeType, RestOtherRanges...>&>(other), false)
+		template <std::ptrdiff_t OtherRange, std::ptrdiff_t... RestOtherRanges>
+		BoundsRanges(const BoundsRanges<OtherRange, RestOtherRanges...>&other, bool firstLevel = true) : Base(static_cast<const BoundsRanges<RestOtherRanges...>&>(other), false)
 		{
 			fail_fast_assert((firstLevel && totalSize() <= other.totalSize()) || totalSize() == other.totalSize());
 		}
 
 		template <typename T, size_t Dim = 0>
-		void serialize(T & arr) const {
+		void serialize(T& arr) const
+        {
 			arr[Dim] = elementNum();
 			this->Base::template serialize<T, Dim + 1>(arr);
 		}
 
 		template <typename T, size_t Dim = 0>
-		SizeType linearize(const T & arr) const {  
+		size_type linearize(const T& arr) const
+        {  
 			fail_fast_assert(arr[Dim] < CurrentRange, "Index is out of range");
-			return static_cast<SizeType>(this->Base::totalSize()) * arr[Dim] + this->Base::template linearize<T, Dim + 1>(arr);
+			return this->Base::totalSize() * arr[Dim] + this->Base::template linearize<T, Dim + 1>(arr);
 		}
 
 		template <typename T, size_t Dim = 0>
-		ptrdiff_t contains(const T & arr) const {
-			if (static_cast<size_t>(arr[Dim]) >= CurrentRange)
+        size_type contains(const T& arr) const
+        {
+			if (arr[Dim] >= CurrentRange)
 				return -1;
-			const ptrdiff_t last = this->Base::template contains<T, Dim + 1>(arr);
+			const size_type last = this->Base::template contains<T, Dim + 1>(arr);
 			if (last == -1)
 				return -1;
-			return static_cast<ptrdiff_t>(this->Base::totalSize() * arr[Dim]) + last;
+			return this->Base::totalSize() * arr[Dim] + last;
 		}
 
-		size_t totalSize() const noexcept{
+		size_type totalSize() const noexcept
+        {
 			return CurrentRange * this->Base::totalSize();
 		}
 
-		SizeType elementNum() const noexcept{
+        size_type elementNum() const noexcept
+        {
 			return CurrentRange;
 		}
 
-		SizeType elementNum(size_t dim) const noexcept{
+		size_type elementNum(size_t dim) const noexcept
+        {
 			if (dim > 0)
 				return this->Base::elementNum(dim - 1);
 			else
 				return elementNum();
 		}
 
-		bool operator == (const BoundsRanges & rhs) const noexcept
+		bool operator== (const BoundsRanges& rhs) const noexcept
 		{
 			return static_cast<const Base &>(*this) == static_cast<const Base &>(rhs);
 		}
@@ -700,7 +646,6 @@ namespace details
 	template <typename SourceType, typename TargetType, size_t Rank>
 	struct BoundsRangeConvertible2;
 
-	// TODO: I have to rewrite BoundsRangeConvertible into following way to workaround VS 2013 bugs
 	template <size_t Rank, typename SourceType, typename TargetType, typename Ret = BoundsRangeConvertible2<typename SourceType::Base, typename TargetType::Base, Rank>>
 	auto helpBoundsRangeConvertible(SourceType, TargetType, std::true_type) -> Ret;
 
@@ -756,56 +701,55 @@ namespace details
 template <typename IndexType>
 class bounds_iterator;
 
-template <typename SizeType, size_t... Ranges>
-class static_bounds {
+template <std::ptrdiff_t... Ranges>
+class static_bounds
+{
 public:
-	static_bounds(const details::BoundsRanges<SizeType, Ranges...> &) {
+	static_bounds(const details::BoundsRanges<Ranges...>&) {
 	}
 };
 
-template <typename SizeType, size_t FirstRange, size_t... RestRanges>
-class static_bounds<SizeType, FirstRange, RestRanges...>
+template <std::ptrdiff_t FirstRange, std::ptrdiff_t... RestRanges>
+class static_bounds<FirstRange, RestRanges...>
 {
-	using MyRanges = details::BoundsRanges <SizeType, FirstRange, RestRanges... >;
-	static_assert(std::is_integral<SizeType>::value
-		&& details::SizeTypeTraits<SizeType>::max_value <= SIZE_MAX, "SizeType must be an integral type and its numeric limits must be smaller than SIZE_MAX");
+	using MyRanges = details::BoundsRanges<FirstRange, RestRanges... >;
 
 	MyRanges m_ranges;
-	constexpr static_bounds(const MyRanges & range) : m_ranges(range) { }
+	constexpr static_bounds(const MyRanges& range) : m_ranges(range)
+    {}
 	
-	template <typename SizeType2, size_t... Ranges2>
+	template <std::ptrdiff_t... OtherRanges>
 	friend class static_bounds;
+
 public:
 	static const size_t rank = MyRanges::Depth;
 	static const size_t dynamic_rank = MyRanges::DynamicNum;
-	static const SizeType static_size = static_cast<SizeType>(MyRanges::TotalSize);
+	static const std::ptrdiff_t static_size = MyRanges::TotalSize;
 
-	using size_type = SizeType;
-	using index_type = index<rank, size_type>;
+	using size_type = std::ptrdiff_t;
+	using index_type = index<rank>;
 	using iterator = bounds_iterator<index_type>;
 	using const_iterator = bounds_iterator<index_type>;
-	using difference_type = ptrdiff_t;
-	using sliced_type = static_bounds<SizeType, RestRanges...>;
+	using difference_type = std::ptrdiff_t;
+	using sliced_type = static_bounds<RestRanges...>;
 	using mapping_type = contiguous_mapping_tag;
 public:
-	constexpr static_bounds(const static_bounds &) = default;
+	constexpr static_bounds(const static_bounds&) = default;
 	
-	template <typename OtherSizeType, size_t... Ranges, typename Dummy = std::enable_if_t<
-		details::BoundsRangeConvertible<details::BoundsRanges<OtherSizeType, Ranges...>, details::BoundsRanges <SizeType, FirstRange, RestRanges... >>::value>>
-	constexpr static_bounds(const static_bounds<OtherSizeType, Ranges...> &other):
-		m_ranges(other.m_ranges)
-	{
-	}
+	template <std::ptrdiff_t... Ranges, typename Dummy = std::enable_if_t<
+		details::BoundsRangeConvertible<details::BoundsRanges<Ranges...>, details::BoundsRanges <FirstRange, RestRanges... >>::value>>
+    constexpr static_bounds(const static_bounds<Ranges...>& other) : m_ranges(other.m_ranges)
+    {}
 
 	constexpr static_bounds(std::initializer_list<size_type> il) : m_ranges(il.begin())
 	{
 		fail_fast_assert(MyRanges::DynamicNum == il.size(), "Size of the initializer list must match the rank of the array");
-		fail_fast_assert(m_ranges.totalSize() <= details::SizeTypeTraits<size_type>::max_value, "Size of the range is larger than the max element of the size type");
+		fail_fast_assert(m_ranges.totalSize() <= PTRDIFF_MAX, "Size of the range is larger than the max element of the size type");
 	}
 	
 	constexpr static_bounds() = default;
 
-	constexpr static_bounds & operator = (const static_bounds & otherBounds)
+	constexpr static_bounds& operator=(const static_bounds& otherBounds)
 	{
 		new(&m_ranges) MyRanges (otherBounds.m_ranges);
 		return *this;
@@ -813,7 +757,7 @@ public:
 
 	constexpr sliced_type slice() const noexcept
 	{
-		return sliced_type{static_cast<const details::BoundsRanges<SizeType, RestRanges...> &>(m_ranges)};
+		return sliced_type{static_cast<const details::BoundsRanges<RestRanges...> &>(m_ranges)};
 	}
 
 	constexpr size_type stride() const noexcept
@@ -823,12 +767,12 @@ public:
 	
 	constexpr size_type size() const noexcept
 	{
-		return static_cast<size_type>(m_ranges.totalSize());
+		return m_ranges.totalSize();
 	}
 
 	constexpr size_type total_size() const noexcept
 	{
-		return static_cast<size_type>(m_ranges.totalSize());
+		return m_ranges.totalSize();
 	}
 	
 	constexpr size_type linearize(const index_type & idx) const
@@ -860,14 +804,14 @@ public:
 		return extents;
 	}
 	
-	template <typename OtherSizeTypes, size_t... Ranges>
-	constexpr bool operator == (const static_bounds<OtherSizeTypes, Ranges...> & rhs) const noexcept
+	template <std::ptrdiff_t... Ranges>
+	constexpr bool operator == (const static_bounds<Ranges...>& rhs) const noexcept
 	{
 		return this->size() == rhs.size();
 	}
 	
-	template <typename OtherSizeTypes, size_t... Ranges>
-	constexpr bool operator != (const static_bounds<OtherSizeTypes, Ranges...> & rhs) const noexcept
+	template <std::ptrdiff_t... Ranges>
+	constexpr bool operator != (const static_bounds<Ranges...>& rhs) const noexcept
 	{
 		return !(*this == rhs);
 	}
@@ -885,12 +829,13 @@ public:
 	}
 };
 
-template <size_t Rank, typename SizeType = size_t>
-class strided_bounds : private details::coordinate_facade<strided_bounds<Rank>, SizeType, Rank>
+template <size_t Rank>
+class strided_bounds : private details::coordinate_facade<strided_bounds<Rank>, Rank>
 {
-	using Base = details::coordinate_facade<strided_bounds<Rank>, SizeType, Rank>;
+	using Base = details::coordinate_facade<strided_bounds<Rank>, Rank>;
 	friend Base;
-	template <size_t OtherRank, typename OtherSizeType>
+
+	template <size_t OtherRank>
 	friend class strided_bounds;
 
 public:
@@ -900,35 +845,31 @@ public:
 	using size_type       = typename Base::value_type;
 	using difference_type = typename Base::value_type;
 	using value_type      = typename Base::value_type;
-	using index_type      = index<rank, size_type>;
+	using index_type      = index<rank>;
 	using iterator        = bounds_iterator<index_type>;
 	using const_iterator  = bounds_iterator<index_type>;
 	static const int dynamic_rank = rank;
-	static const size_t static_size = dynamic_range;
+	static const std::ptrdiff_t static_size = dynamic_range;
 	using sliced_type = std::conditional_t<rank != 0, strided_bounds<rank - 1>, void>;
 	using mapping_type = generalized_mapping_tag;
 	constexpr strided_bounds(const strided_bounds &) = default;
 
-	template <typename OtherSizeType>
-	constexpr strided_bounds(const strided_bounds<rank, OtherSizeType> &other) 
-		: Base(other), m_strides(other.strides)
-	{
-	}
-
-	constexpr strided_bounds(const index_type &extents, const index_type &strides) 
-		: m_strides(strides)
+	constexpr strided_bounds(const index_type& extents, const index_type& strides)
+    : m_strides(strides)
 	{
 		for (size_t i = 0; i < rank; i++)
 			Base::elems[i] = extents[i];
 	}
-	constexpr strided_bounds(const value_type(&values)[rank], index_type strides)
-		: Base(values), m_strides(std::move(strides))
-	{
-	}
+
+    constexpr strided_bounds(const value_type(&values)[rank], index_type strides)
+        : Base(values), m_strides(std::move(strides))
+    {}
+
 	constexpr index_type strides() const noexcept
 	{ 
 		return m_strides;  
 	}
+
 	constexpr size_type total_size() const noexcept
 	{
 		size_type ret = 0;
@@ -936,14 +877,16 @@ public:
 			ret += (Base::elems[i] - 1) * m_strides[i];
 		return ret + 1;
 	}
-	constexpr size_type size() const noexcept
+	
+    constexpr size_type size() const noexcept
 	{
 		size_type ret = 1;
 		for (size_t i = 0; i < rank; ++i)
 			ret *= Base::elems[i];
 		return ret;
 	}
-	constexpr bool contains(const index_type& idx) const noexcept
+	
+    constexpr bool contains(const index_type& idx) const noexcept
 	{
 		for (size_t i = 0; i < rank; ++i)
 		{
@@ -952,7 +895,8 @@ public:
 		}
 		return true;
 	}
-	constexpr size_type linearize(const index_type & idx) const
+	
+    constexpr size_type linearize(const index_type & idx) const
 	{
 		size_type ret = 0;
 		for (size_t i = 0; i < rank; i++)
@@ -962,43 +906,50 @@ public:
 		}
 		return ret;
 	}
-	constexpr size_type stride() const noexcept
+	
+    constexpr size_type stride() const noexcept
 	{
 		return m_strides[0];
 	}
-	template <bool Enabled = (rank > 1), typename Ret = std::enable_if_t<Enabled, sliced_type>>
+	
+    template <bool Enabled = (rank > 1), typename Ret = std::enable_if_t<Enabled, sliced_type>>
 	constexpr sliced_type slice() const
 	{
 		return{ (value_type(&)[rank - 1])Base::elems[1], sliced_type::index_type::shift_left(m_strides) };
 	}
-	template <size_t Dim = 0>
+	
+    template <size_t Dim = 0>
 	constexpr size_type extent() const noexcept
 	{
 		static_assert(Dim < Rank, "dimension should be less than rank (dimension count starts from 0)");
 		return Base::elems[Dim];
 	}
-	constexpr index_type index_bounds() const noexcept
+	
+    constexpr index_type index_bounds() const noexcept
 	{
 		return index_type(Base::elems);
 	}
-	const_iterator begin() const noexcept
+	
+    const_iterator begin() const noexcept
 	{
 		return const_iterator{ *this };
 	}
-	const_iterator end() const noexcept
+	
+    const_iterator end() const noexcept
 	{
 		return const_iterator{ *this, index_bounds() };
 	}
+
 private:
 	index_type m_strides;
 };
 
 template <typename T>
 struct is_bounds : std::integral_constant<bool, false> {};
-template <typename SizeType, size_t... Ranges>
-struct is_bounds<static_bounds<SizeType, Ranges...>> : std::integral_constant<bool, true> {};
-template <size_t Rank, typename SizeType>
-struct is_bounds<strided_bounds<Rank, SizeType>> : std::integral_constant<bool, true> {};
+template <std::ptrdiff_t... Ranges>
+struct is_bounds<static_bounds<Ranges...>> : std::integral_constant<bool, true> {};
+template <size_t Rank>
+struct is_bounds<strided_bounds<Rank>> : std::integral_constant<bool, true> {};
 
 template <typename IndexType>
 class bounds_iterator
@@ -1194,26 +1145,26 @@ private:
 	value_type curr;
 };
 
-template <typename SizeType>
-class bounds_iterator<index<1, SizeType>>
+template <>
+class bounds_iterator<index<1>>
 	: public std::iterator<std::random_access_iterator_tag,
-	index<1, SizeType>,
+	index<1>,
 	ptrdiff_t,
-	const details::arrow_proxy<index<1, SizeType>>,
-	const index<1, SizeType>>
+	const details::arrow_proxy<index<1>>,
+	const index<1>>
 {
-	using Base = std::iterator<std::random_access_iterator_tag, index<1, SizeType>, ptrdiff_t, const details::arrow_proxy<index<1, SizeType>>, const index<1, SizeType>>;
+	using Base = std::iterator<std::random_access_iterator_tag, index<1>, std::ptrdiff_t, const details::arrow_proxy<index<1>>, const index<1>>;
 
 public:
-	using typename Base::reference;
-	using typename Base::pointer;
-	using typename Base::difference_type;
-	using typename Base::value_type;
+	using Base::reference;
+	using Base::pointer;
+	using Base::difference_type;
+	using Base::value_type;
 	using index_type = value_type;
-	using index_size_type = typename index_type::size_type;
+	using index_size_type = index_type::size_type;
 
 	template <typename Bounds>
-	explicit bounds_iterator(const Bounds &, value_type curr = value_type{}) noexcept
+	explicit bounds_iterator(const Bounds&, value_type curr = value_type{}) noexcept
 		: curr( std::move(curr) )
 	{}
 	reference operator*() const noexcept
@@ -1311,9 +1262,9 @@ bounds_iterator<IndexType> operator+(typename bounds_iterator<IndexType>::differ
 	return rhs + n;
 }
 
-/*
-** begin definitions of basic_array_view
-*/
+//
+// begin definitions of basic_array_view
+//
 namespace details
 {
 	template <typename Bounds>
@@ -1519,22 +1470,23 @@ private:
 	friend class basic_array_view;
 };
 
-template <size_t DimSize = dynamic_range>
+template <std::ptrdiff_t DimSize = dynamic_range>
 struct dim
 {
-	static const size_t value = DimSize;
+	static const std::ptrdiff_t value = DimSize;
 };
 template <>
 struct dim<dynamic_range>
 {
-	static const size_t value = dynamic_range;
-	const size_t dvalue;
-	dim(size_t size) : dvalue(size) {}
+	static const std::ptrdiff_t value = dynamic_range;
+	const std::ptrdiff_t dvalue;
+	dim(std::ptrdiff_t size) : dvalue(size) {}
 };
 
-template <typename ValueTypeOpt, size_t FirstDimension = dynamic_range, size_t... RestDimensions>
+template <typename ValueType, std::ptrdiff_t FirstDimension = dynamic_range, std::ptrdiff_t... RestDimensions>
 class array_view;
-template <typename ValueTypeOpt, size_t Rank>
+
+template <typename ValueType, size_t Rank>
 class strided_array_view;
 
 namespace details
@@ -1553,31 +1505,31 @@ namespace details
 		using size_type = typename Traits::array_view_traits::size_type;
 	};
 
-	template <typename T, typename SizeType, size_t... Ranks>
+	template <typename T, size_t... Ranks>
 	struct ArrayViewArrayTraits {
 		using type = array_view<T, Ranks...>;
 		using value_type = T;
-		using bounds_type = static_bounds<SizeType, Ranks...>;
+		using bounds_type = static_bounds<Ranks...>;
 		using pointer = T*;
 		using reference = T&;
 	};
-	template <typename T, typename SizeType, size_t N, size_t... Ranks>
-	struct ArrayViewArrayTraits<T[N], SizeType, Ranks...> : ArrayViewArrayTraits<T, SizeType, Ranks..., N> {};
+	template <typename T, size_t N, size_t... Ranks>
+	struct ArrayViewArrayTraits<T[N], Ranks...> : ArrayViewArrayTraits<T, Ranks..., N> {};
 
 	template <typename BoundsType>
-	BoundsType newBoundsHelperImpl(size_t totalSize, std::true_type) // dynamic size
+	BoundsType newBoundsHelperImpl(std::ptrdiff_t , std::true_type) // dynamic size
 	{
-		fail_fast_assert(totalSize <= details::SizeTypeTraits<typename BoundsType::size_type>::max_value);
-		return BoundsType{static_cast<typename BoundsType::size_type>(totalSize)};
+		fail_fast_assert(totalSize <= PTRDIFF_MAX);
+		return BoundsType{totalSize};
 	}
 	template <typename BoundsType>
-	BoundsType newBoundsHelperImpl(size_t totalSize, std::false_type) // static size
+	BoundsType newBoundsHelperImpl(std::ptrdiff_t totalSize, std::false_type) // static size
 	{
 		fail_fast_assert(BoundsType::static_size == totalSize);
 		return {};
 	}
 	template <typename BoundsType>
-	BoundsType newBoundsHelper(size_t totalSize)
+	BoundsType newBoundsHelper(std::ptrdiff_t totalSize)
 	{
 		static_assert(BoundsType::dynamic_rank <= 1, "dynamic rank must less or equal to 1");
 		return newBoundsHelperImpl<BoundsType>(totalSize, std::integral_constant<bool, BoundsType::dynamic_rank == 1>());
@@ -1601,46 +1553,38 @@ namespace details
 		return static_as_array_view_helper<T>(args..., val.dvalue);
 	}
 
-	template <typename SizeType, typename ...Dimensions>
+	template <typename ...Dimensions>
 	struct static_as_array_view_static_bounds_helper
 	{
-		using type = static_bounds<SizeType, (Dimensions::value)...>;
+		using type = static_bounds<(Dimensions::value)...>;
 	};
 
 	template <typename T>
 	struct is_array_view_oracle : std::false_type
 	{};
-	template <typename ValueType, size_t FirstDimension, size_t... RestDimensions>
+
+	template <typename ValueType, std::ptrdiff_t FirstDimension, std::ptrdiff_t... RestDimensions>
 	struct is_array_view_oracle<array_view<ValueType, FirstDimension, RestDimensions...>> : std::true_type
 	{};
-	template <typename ValueType, size_t Rank>
+	
+    template <typename ValueType, size_t Rank>
 	struct is_array_view_oracle<strided_array_view<ValueType, Rank>> : std::true_type
 	{};
-	template <typename T>
+	
+    template <typename T>
 	struct is_array_view : is_array_view_oracle<std::remove_cv_t<T>>
 	{};
 
 }
 
 
-template <typename ValueType, typename SizeType>
-struct array_view_options
+template <typename ValueType, std::ptrdiff_t FirstDimension, std::ptrdiff_t... RestDimensions>
+class array_view : public basic_array_view <ValueType, static_bounds <FirstDimension, RestDimensions...>>
 {
-	struct array_view_traits
-	{
-		using value_type = ValueType;
-		using size_type = SizeType;
-	};
-};
-
-template <typename ValueTypeOpt, size_t FirstDimension, size_t... RestDimensions>
-class array_view : public basic_array_view<typename details::ArrayViewTypeTraits<ValueTypeOpt>::value_type, 
-	static_bounds<typename details::ArrayViewTypeTraits<ValueTypeOpt>::size_type, FirstDimension, RestDimensions...>>
-{
-	template <typename ValueTypeOpt2, size_t FirstDimension2, size_t... RestDimensions2>
+	template <typename ValueType2, std::ptrdiff_t FirstDimension2, std::ptrdiff_t... RestDimensions2>
 	friend class array_view;
-	using Base = basic_array_view<typename details::ArrayViewTypeTraits<ValueTypeOpt>::value_type,
-		static_bounds<typename details::ArrayViewTypeTraits<ValueTypeOpt>::size_type, FirstDimension, RestDimensions...>>;
+
+	using Base = basic_array_view<ValueType, static_bounds<FirstDimension, RestDimensions...>>;
 
 public:
 	using typename Base::bounds_type;
@@ -1655,13 +1599,14 @@ public:
 
 public:
 	// basic
-	constexpr array_view(pointer ptr, bounds_type bounds) : Base(ptr, std::move(bounds))
-	{
-	}
+    constexpr array_view(pointer ptr, size_type size) : Base(ptr, bounds_type{ size })
+    {}
+
+    constexpr array_view(pointer ptr, bounds_type bounds) : Base(ptr, std::move(bounds))
+    {}
 
 	constexpr array_view(std::nullptr_t) : Base(nullptr, bounds_type{})
-	{
-	}
+	{}
 
 	constexpr array_view(std::nullptr_t, size_type size) : Base(nullptr, bounds_type{})
 	{
@@ -1671,108 +1616,102 @@ public:
 	// default
 	template <size_t DynamicRank = bounds_type::dynamic_rank, typename Dummy = std::enable_if_t<DynamicRank != 0>>
 	constexpr array_view() : Base(nullptr, bounds_type())
-	{
-	}
+	{}
 
 	// from n-dimensions dynamic array (e.g. new int[m][4]) (precedence will be lower than the 1-dimension pointer)
-	template <typename T, typename Helper = details::ArrayViewArrayTraits<T, size_type, dynamic_range>,
-		typename Dummy = std::enable_if_t<std::is_convertible<typename Helper::value_type (*)[], typename Base::value_type (*)[]>::value
-			&& std::is_convertible<typename Helper::bounds_type, typename Base::bounds_type>::value>>
-	constexpr array_view(T * const & data, size_type size) : Base(data, typename Helper::bounds_type{size})
-	{
-	}
+	template <typename T, typename Helper = details::ArrayViewArrayTraits<T, dynamic_range>
+        typename Dummy = std::enable_if_t<std::is_convertible<Helper::value_type (*)[], typename Base::value_type (*)[]>::value>>
+	constexpr array_view(T* const& data, size_type size) : Base(data, typename Helper::bounds_type{size})
+	{}
 
 	// from n-dimensions static array
-	template <typename T, size_t N, typename Helper = details::ArrayViewArrayTraits<T, size_type, N>,
-		typename Dummy = std::enable_if_t<std::is_convertible<typename Helper::value_type(*)[], typename Base::value_type(*)[]>::value
-		&& std::is_convertible<typename Helper::bounds_type, typename Base::bounds_type>::value>>
+	template <typename T, size_t N, typename Helper = details::ArrayViewArrayTraits<T, dynamic_range>
+		typename Dummy = std::enable_if_t<std::is_convertible<typename Helper::value_type(*)[], typename Base::value_type(*)[]>::value>
+    >
 	constexpr array_view (T (&arr)[N]) : Base(arr, typename Helper::bounds_type())
-	{
-	}
+	{}
 
 	// from n-dimensions static array with size
-	template <typename T, size_t N, typename Helper = details::ArrayViewArrayTraits<T, size_type, dynamic_range>,
-		typename Dummy = std::enable_if_t<std::is_convertible<typename Helper::value_type(*)[], typename Base::value_type(*)[]>::value
-			&& std::is_convertible<typename Helper::bounds_type, typename Base::bounds_type>::value >>
+	template <typename T, size_t N,
+		typename Dummy = std::enable_if_t<std::is_convertible<T(*)[], typename Base::value_type(*)[]>::value>
+    >
 	constexpr array_view(T(&arr)[N], size_type size) : Base(arr, typename Helper::bounds_type{ size })
 	{
 		fail_fast_assert(size <= N);
 	}
 
 	// from std array
-	template <size_t N, typename Dummy = std::enable_if_t<std::is_convertible<static_bounds<size_type, N>, typename Base::bounds_type>::value>>
-	constexpr array_view (std::array<std::remove_const_t<value_type>, N> & arr) : Base(arr.data(), static_bounds<size_type, N>())
-	{
-	}
-
-	template <size_t N, typename Dummy = std::enable_if_t<std::is_convertible<static_bounds<size_type, N>, typename Base::bounds_type>::value && std::is_const<value_type>::value>>
-	constexpr array_view (const std::array<std::remove_const_t<value_type>, N> & arr) : Base(arr.data(), static_bounds<size_type, N>())
-	{
-	}
-
+	template <size_t N, 
+       typename Dummy = std::enable_if_t<std::is_convertible<static_bounds<N>, typename Base::bounds_type>::value>
+    >
+	constexpr array_view (std::array<std::remove_const_t<value_type>, N> & arr) : Base(arr.data(), static_bounds<N>())
+	{}
 
+	template <size_t N,
+        typename Dummy = std::enable_if_t<std::is_convertible<static_bounds<N>, typename Base::bounds_type>::value
+        && std::is_const<value_type>::value>
+    >
+	constexpr array_view (const std::array<std::remove_const_t<value_type>, N> & arr) : Base(arr.data(), static_bounds<N>())
+	{}
+    
 	// from begin, end pointers. We don't provide iterator pair since no way to guarantee the contiguity 
 	template <typename Ptr,
 		typename Dummy = std::enable_if_t<std::is_convertible<Ptr, pointer>::value
-		&& details::LessThan<Base::bounds_type::dynamic_rank, 2>::value>> // remove literal 0 case
+		&& details::LessThan<Base::bounds_type::dynamic_rank, 2>::value>
+    > // remove literal 0 case
 	constexpr array_view (pointer begin, Ptr end) : Base(begin, details::newBoundsHelper<typename Base::bounds_type>(static_cast<pointer>(end) - begin))
-	{
-	}
+	{}
 
 	// from containers. It must has .size() and .data() two function signatures
-	template <typename Cont, typename DataType = typename Cont::value_type, typename SizeType = typename Cont::size_type,
+	template <typename Cont, typename DataType = typename Cont::value_type,
 		typename Dummy = std::enable_if_t<!details::is_array_view<Cont>::value
 		&& std::is_convertible<DataType (*)[], typename Base::value_type (*)[]>::value
-		&& std::is_convertible<static_bounds<SizeType, dynamic_range>, typename Base::bounds_type>::value
 		&& std::is_same<std::decay_t<decltype(std::declval<Cont>().size(), *std::declval<Cont>().data())>, DataType>::value>
 	>
 	constexpr array_view (Cont& cont) : Base(static_cast<pointer>(cont.data()), details::newBoundsHelper<typename Base::bounds_type>(cont.size()))
-	{
+	{}
 
-	}
-
-	constexpr  array_view(const array_view &) = default;
+	constexpr array_view(const array_view &) = default;
 
 	// convertible
-	template <typename OtherValueTypeOpt, size_t... OtherDimensions,
-		typename BaseType = basic_array_view<typename details::ArrayViewTypeTraits<ValueTypeOpt>::value_type, static_bounds<typename details::ArrayViewTypeTraits<ValueTypeOpt>::size_type, FirstDimension, RestDimensions...>>,
-		typename OtherBaseType = basic_array_view<typename details::ArrayViewTypeTraits<OtherValueTypeOpt>::value_type, static_bounds<typename details::ArrayViewTypeTraits<OtherValueTypeOpt>::size_type, OtherDimensions...>>,
+	template <typename OtherValueType, std::ptrdiff_t... OtherDimensions,
+		typename BaseType = basic_array_view<ValueType, static_bounds<FirstDimension, RestDimensions...>>,
+		typename OtherBaseType = basic_array_view<OtherValueType, static_bounds<OtherDimensions...>>,
 		typename Dummy = std::enable_if_t<std::is_convertible<OtherBaseType, BaseType>::value>
 	>
-	constexpr array_view(const array_view<OtherValueTypeOpt, OtherDimensions...> &av) : Base(static_cast<const typename array_view<OtherValueTypeOpt, OtherDimensions...>::Base &>(av)) {} // static_cast is required
+	constexpr array_view(const array_view<OtherValueType, OtherDimensions...> &av)
+        : Base(static_cast<const typename array_view<OtherValueType, OtherDimensions...>::Base&>(av))
+    {}
 
 	// reshape
 	template <typename... Dimensions2>
-	constexpr array_view<ValueTypeOpt, Dimensions2::value...> as_array_view(Dimensions2... dims)
+	constexpr array_view<ValueType, Dimensions2::value...> as_array_view(Dimensions2... dims)
 	{
 		static_assert(sizeof...(Dimensions2) > 0, "the target array_view must have at least one dimension.");
-		using BoundsType = typename array_view<ValueTypeOpt, (Dimensions2::value)...>::bounds_type;
+		using BoundsType = typename array_view<ValueType, (Dimensions2::value)...>::bounds_type;
 		auto tobounds = details::static_as_array_view_helper<BoundsType>(dims..., details::Sep{});
 		details::verifyBoundsReshape(this->bounds(), tobounds);
 		return {this->data(), tobounds};
 	}
 
 	// to bytes array
-	template <bool Enabled = std::is_standard_layout<std::decay_t<typename details::ArrayViewTypeTraits<ValueTypeOpt>::value_type>>::value>
-	constexpr auto as_bytes() const noexcept ->
-		array_view<array_view_options<const byte, size_type>, static_cast<size_t>(details::StaticSizeHelper<size_type, Base::bounds_type::static_size, sizeof(value_type)>::value)>
+	template <bool Enabled = std::is_standard_layout<std::decay_t<ValueType>>::value>
+	constexpr auto as_bytes() const noexcept -> array_view<const byte>
 	{
 		static_assert(Enabled, "The value_type of array_view must be standarded layout");
 		return { reinterpret_cast<const byte*>(this->data()), this->bytes() };
 	}
 
-	template <bool Enabled = std::is_standard_layout<std::decay_t<typename details::ArrayViewTypeTraits<ValueTypeOpt>::value_type>>::value>
-	constexpr auto as_writeable_bytes() const noexcept ->
-		array_view<array_view_options<byte, size_type>, static_cast<size_t>(details::StaticSizeHelper<size_type, Base::bounds_type::static_size, sizeof(value_type)>::value)>
+	template <bool Enabled = std::is_standard_layout<std::decay_t<ValueType>>::value>
+	constexpr auto as_writeable_bytes() const noexcept -> array_view<byte>
 	{
 		static_assert(Enabled, "The value_type of array_view must be standarded layout");
 		return { reinterpret_cast<byte*>(this->data()), this->bytes() };
 	}
 
-
-	// from bytes array
+    // from bytes array
 	template<typename U, bool IsByte = std::is_same<value_type, const byte>::value, typename Dummy = std::enable_if_t<IsByte && sizeof...(RestDimensions) == 0>>
-	constexpr auto as_array_view() const noexcept -> array_view<const U, (Base::bounds_type::dynamic_rank == 0 ? Base::bounds_type::static_size / sizeof(U) : static_cast<size_type>(dynamic_range))>
+	constexpr auto as_array_view() const noexcept -> array_view<const U, (Base::bounds_type::dynamic_rank == 0 ? Base::bounds_type::static_size / sizeof(U) : dynamic_range)>
 	{
 		static_assert(std::is_standard_layout<U>::value && (Base::bounds_type::static_size == dynamic_range || Base::bounds_type::static_size % sizeof(U) == 0),
 			"Target type must be standard layout and its size must match the byte array size");
@@ -1781,7 +1720,7 @@ public:
 	}
 
 	template<typename U, bool IsByte = std::is_same<value_type, byte>::value, typename Dummy = std::enable_if_t<IsByte && sizeof...(RestDimensions) == 0>>
-	constexpr auto as_array_view() const noexcept -> array_view<U, (Base::bounds_type::dynamic_rank == 0 ? Base::bounds_type::static_size / sizeof(U) : static_cast<size_type>(dynamic_range))>
+	constexpr auto as_array_view() const noexcept -> array_view<U, (Base::bounds_type::dynamic_rank == 0 ? Base::bounds_type::static_size / sizeof(U) : dynamic_range)>
 	{
 		static_assert(std::is_standard_layout<U>::value && (Base::bounds_type::static_size == dynamic_range || Base::bounds_type::static_size % sizeof(U) == 0),
 			"Target type must be standard layout and its size must match the byte array size");
@@ -1790,43 +1729,43 @@ public:
 	}
 
 	// section on linear space
-	template<size_t Count>
-	constexpr array_view<ValueTypeOpt, Count> first() const noexcept
+	template<std::ptrdiff_t Count>
+	constexpr array_view<ValueType, Count> first() const noexcept
 	{
 		static_assert(bounds_type::static_size == dynamic_range || Count <= bounds_type::static_size, "Index is out of bound");
 		fail_fast_assert(bounds_type::static_size != dynamic_range || Count <= this->size()); // ensures we only check condition when needed
 		return { this->data(), Count };
 	}
 
-	constexpr array_view<ValueTypeOpt, dynamic_range> first(size_type count) const noexcept
+	constexpr array_view<ValueType, dynamic_range> first(size_type count) const noexcept
 	{
 		fail_fast_assert(count <= this->size());
 		return { this->data(), count };
 	}
 
-	template<size_t Count>
-	constexpr array_view<ValueTypeOpt, Count> last() const noexcept
+	template<std::ptrdiff_t Count>
+	constexpr array_view<ValueType, Count> last() const noexcept
 	{
 		static_assert(bounds_type::static_size == dynamic_range || Count <= bounds_type::static_size, "Index is out of bound");
 		fail_fast_assert(bounds_type::static_size != dynamic_range || Count <= this->size());
 		return { this->data() + this->size() - Count, Count };
 	}
 
-	constexpr array_view<ValueTypeOpt, dynamic_range> last(size_type count) const noexcept
+	constexpr array_view<ValueType, dynamic_range> last(size_type count) const noexcept
 	{
 		fail_fast_assert(count <= this->size());
 		return { this->data() + this->size() - count, count };
 	}
 
-	template<size_t Offset, size_t Count>
-	constexpr array_view<ValueTypeOpt, Count> sub() const noexcept
+	template<std::ptrdiff_t Offset, std::ptrdiff_t Count>
+	constexpr array_view<ValueType, Count> sub() const noexcept
 	{
 		static_assert(bounds_type::static_size == dynamic_range || ((Offset == 0 || Offset <= bounds_type::static_size) && Offset + Count <= bounds_type::static_size), "Index is out of bound");
 		fail_fast_assert(bounds_type::static_size != dynamic_range || ((Offset == 0 || Offset <= this->size()) && Offset + Count <= this->size()));
 		return { this->data() + Offset, Count };
 	}
 
-	constexpr array_view<ValueTypeOpt, dynamic_range> sub(size_type offset, size_type count = dynamic_range) const noexcept
+	constexpr array_view<ValueType, dynamic_range> sub(size_type offset, size_type count = dynamic_range) const noexcept
 	{
 		fail_fast_assert((offset == 0 || offset <= this->size()) && (count == dynamic_range || (offset + count) <= this->size()));
 		return { this->data() + offset, count == dynamic_range ? this->length() - offset : count };
@@ -1837,24 +1776,27 @@ public:
 	{
 		return this->size();
 	}
+
 	constexpr size_type used_length() const noexcept
 	{
 		return length();
 	}
+
 	constexpr size_type bytes() const noexcept
 	{
 		return sizeof(value_type) * this->size();
 	}
+
 	constexpr size_type used_bytes() const noexcept
 	{
 		return bytes();
 	}
 
 	// section
-	constexpr strided_array_view<ValueTypeOpt, rank> section(index_type origin, index_type extents) const
+	constexpr strided_array_view<ValueType, rank> section(index_type origin, index_type extents) const
 	{
 		size_type size = this->bounds().total_size() - this->bounds().linearize(origin);
-		return{ &this->operator[](origin), size, strided_bounds<rank, size_type> {extents, details::make_stride(Base::bounds())} };
+		return{ &this->operator[](origin), size, strided_bounds<rank> {extents, details::make_stride(Base::bounds())} };
 	}
 	
 		constexpr reference operator[](const index_type& idx) const
@@ -1863,7 +1805,7 @@ public:
 	}
 	
 		template <bool Enabled = (rank > 1), typename Dummy = std::enable_if_t<Enabled>>
-	constexpr array_view<ValueTypeOpt, RestDimensions...> operator[](size_type idx) const
+	constexpr array_view<ValueType, RestDimensions...> operator[](size_type idx) const
 	{
 		auto ret = Base::operator[](idx);
 		return{ ret.data(), ret.bounds() };
@@ -1877,20 +1819,20 @@ public:
 	using Base::operator>=;
 };
 
-template <typename T, size_t... Dimensions>
-constexpr auto as_array_view(T * const & ptr, dim<Dimensions>... args) -> array_view<std::remove_all_extents_t<T>, Dimensions...>
+template <typename T, std::ptrdiff_t... Dimensions>
+constexpr auto as_array_view(T* const& ptr, dim<Dimensions>... args) -> array_view<std::remove_all_extents_t<T>, Dimensions...>
 {
-	return {reinterpret_cast<std::remove_all_extents_t<T>*>(ptr), details::static_as_array_view_helper<static_bounds<size_t, Dimensions...>>(args..., details::Sep{})};
+	return {reinterpret_cast<std::remove_all_extents_t<T>*>(ptr), details::static_as_array_view_helper<static_bounds<Dimensions...>>(args..., details::Sep{})};
 }
 
 template <typename T>
-constexpr auto as_array_view (T * arr, size_t len) -> typename details::ArrayViewArrayTraits<T, size_t, dynamic_range>::type
+constexpr auto as_array_view (T* arr, std::ptrdiff_t len) -> typename details::ArrayViewArrayTraits<T, dynamic_range>::type
 {
-	return {arr, len};
+	return {reinterpret_cast<std::remove_all_extents_t<T>*>(arr), len};
 }
 
 template <typename T, size_t N>
-constexpr auto as_array_view (T (&arr)[N]) -> typename details::ArrayViewArrayTraits<T, size_t, N>::type
+constexpr auto as_array_view (T (&arr)[N]) -> typename details::ArrayViewArrayTraits<T, N>::type
 {
 	return {arr};
 }
@@ -1927,13 +1869,14 @@ template <typename Cont>
 constexpr auto as_array_view(Cont &&arr) -> std::enable_if_t<!details::is_array_view<std::decay_t<Cont>>::value,
 	array_view<std::remove_reference_t<decltype(arr.size(), *arr.data())>, dynamic_range>> = delete;
 
-template <typename ValueTypeOpt, size_t Rank>
-class strided_array_view : public basic_array_view<typename details::ArrayViewTypeTraits<ValueTypeOpt>::value_type, strided_bounds<Rank, typename details::ArrayViewTypeTraits<ValueTypeOpt>::size_type>>
+template <typename ValueType, size_t Rank>
+class strided_array_view : public basic_array_view<ValueType, strided_bounds<Rank>>
 {
-	using Base = basic_array_view<typename details::ArrayViewTypeTraits<ValueTypeOpt>::value_type, strided_bounds<Rank, typename details::ArrayViewTypeTraits<ValueTypeOpt>::size_type>>;
+	using Base = basic_array_view<ValueType, strided_bounds<Rank>>;
 
-	template<typename OtherValueOpt, size_t OtherRank>
+	template<typename OtherValue, size_t OtherRank>
 	friend class strided_array_view;
+
 public:
 	using Base::rank;
 	using typename Base::bounds_type;
@@ -1959,21 +1902,20 @@ public:
 	}
 
 	// from array view
-	template <size_t... Dimensions, typename Dummy = std::enable_if<sizeof...(Dimensions) == Rank>>
-	strided_array_view(array_view<ValueTypeOpt, Dimensions...> av, bounds_type bounds) : Base(av.data(), std::move(bounds))
+	template <std::ptrdiff_t... Dimensions, typename Dummy = std::enable_if<sizeof...(Dimensions) == Rank>>
+	strided_array_view(array_view<ValueType, Dimensions...> av, bounds_type bounds) : Base(av.data(), std::move(bounds))
 	{
 		fail_fast_assert(this->bounds().total_size() <= av.bounds().total_size(), "Bounds cross data boundaries");
 	}
 	
 	// convertible
-	template <typename OtherValueTypeOpt,
-		typename BaseType = basic_array_view<typename details::ArrayViewTypeTraits<ValueTypeOpt>::value_type, strided_bounds<Rank, typename details::ArrayViewTypeTraits<ValueTypeOpt>::size_type>>,
-		typename OtherBaseType = basic_array_view<typename details::ArrayViewTypeTraits<OtherValueTypeOpt>::value_type, strided_bounds<Rank, typename details::ArrayViewTypeTraits<OtherValueTypeOpt>::size_type>>,
+	template <typename OtherValueType,
+		typename BaseType = basic_array_view<ValueType, strided_bounds<Rank>>,
+		typename OtherBaseType = basic_array_view<OtherValueType, strided_bounds<Rank>>,
 		typename Dummy = std::enable_if_t<std::is_convertible<OtherBaseType, BaseType>::value>
 	>
-	constexpr strided_array_view(const strided_array_view<OtherValueTypeOpt, Rank> &av): Base(static_cast<const typename strided_array_view<OtherValueTypeOpt, Rank>::Base &>(av)) // static_cast is required
-	{
-	}
+    constexpr strided_array_view(const strided_array_view<OtherValueType, Rank> &av) : Base(static_cast<const typename strided_array_view<OtherValueType, Rank>::Base &>(av)) // static_cast is required
+    {}
 
 	// convert from bytes
 		template <typename OtherValueType>
@@ -2047,17 +1989,21 @@ public:
 	using typename Base::reference;
 	using typename Base::pointer;
 	using typename Base::difference_type;
+
 private:
 	template <typename ValueType, typename Bounds>
 	friend class basic_array_view;
-	pointer m_pdata;
+
+    pointer m_pdata;
 	const ArrayView * m_validator;
 	void validateThis() const
 	{
 		fail_fast_assert(m_pdata >= m_validator->m_pdata && m_pdata < m_validator->m_pdata + m_validator->size(), "iterator is out of range of the array");
 	}
-	contiguous_array_view_iterator (const ArrayView *container, bool isbegin = false) :
+	
+    contiguous_array_view_iterator (const ArrayView *container, bool isbegin = false) :
 		m_pdata(isbegin ? container->m_pdata : container->m_pdata + container->size()), m_validator(container) {	}
+
 public:
 	reference operator*() const noexcept
 	{
@@ -2170,12 +2116,14 @@ public:
 private:
 	template <typename ValueType, typename Bounds>
 	friend class basic_array_view;
-	const ArrayView * m_container;
+	
+    const ArrayView * m_container;
 	typename ArrayView::bounds_type::iterator m_itr;
-	general_array_view_iterator(const ArrayView *container, bool isbegin = false) :
-		m_container(container), m_itr(isbegin ? m_container->bounds().begin() : m_container->bounds().end())
-	{
-	}
+    
+    general_array_view_iterator(const ArrayView *container, bool isbegin = false) :
+        m_container(container), m_itr(isbegin ? m_container->bounds().begin() : m_container->bounds().end())
+    {}
+
 public:
 	reference operator*() const noexcept
 	{
diff --git a/include/string_view.h b/include/string_view.h
index 4076d52..04909f8 100644
--- a/include/string_view.h
+++ b/include/string_view.h
@@ -34,16 +34,16 @@ namespace gsl
 // type system for these types that will not either incur significant runtime costs or
 // (sometimes needlessly) break existing programs when introduced.
 //
-template<size_t Max = dynamic_range>
+template<std::ptrdiff_t Max = dynamic_range>
 using czstring = const char*;
 
-template<size_t Max = dynamic_range>
+template<std::ptrdiff_t Max = dynamic_range>
 using cwzstring = const wchar_t*;
 
-template<size_t Max = dynamic_range>
+template<std::ptrdiff_t Max = dynamic_range>
 using zstring = char*;
 
-template<size_t Max = dynamic_range>
+template<std::ptrdiff_t Max = dynamic_range>
 using wzstring = wchar_t*;
 
 //
@@ -54,19 +54,19 @@ using wzstring = wchar_t*;
 //
 // TODO (neilmac) once array_view regains configurable size_type, update these typedef's
 //
-template <class CharT, size_t Extent = dynamic_range>
+template <class CharT, std::ptrdiff_t Extent = dynamic_range>
 using basic_string_view = array_view<CharT, Extent>;
 
-template<size_t Extent = dynamic_range>
+template<std::ptrdiff_t Extent = dynamic_range>
 using string_view = basic_string_view<char, Extent>;
 
-template<size_t Extent = dynamic_range>
+template<std::ptrdiff_t Extent = dynamic_range>
 using cstring_view = basic_string_view<const char, Extent>;
 
-template<size_t Extent = dynamic_range>
+template<std::ptrdiff_t Extent = dynamic_range>
 using wstring_view = basic_string_view<wchar_t, Extent>;
 
-template<size_t Extent = dynamic_range>
+template<std::ptrdiff_t Extent = dynamic_range>
 using cwstring_view = basic_string_view<const wchar_t, Extent>;
 
 
@@ -94,38 +94,39 @@ array_view<T, dynamic_range> ensure_sentinel(const T* seq, SizeType max = std::n
 // the limit of size_type.
 //
 template<class T>
-inline basic_string_view<T, dynamic_range> ensure_z(T* const & sz, size_t max = std::numeric_limits<size_t>::max())
+inline basic_string_view<T, dynamic_range> ensure_z(T* const & sz, std::ptrdiff_t max = PTRDIFF_MAX)
 {
     return ensure_sentinel<0>(sz, max);
 }
 
 // TODO (neilmac) there is probably a better template-magic way to get the const and non-const overloads to share an implementation
-inline basic_string_view<char, dynamic_range> ensure_z(char* const & sz, size_t max)
+inline basic_string_view<char, dynamic_range> ensure_z(char* const& sz, std::ptrdiff_t max)
 {
     auto len = strnlen(sz, max);
-    fail_fast_assert(sz[len] == 0); return{ sz, len };
+    fail_fast_assert(sz[len] == 0);
+    return{ sz, static_cast<std::ptrdiff_t>(len) };
 }
 
-inline basic_string_view<const char, dynamic_range> ensure_z(const char* const& sz, size_t max)
+inline basic_string_view<const char, dynamic_range> ensure_z(const char* const& sz, std::ptrdiff_t max)
 {
     auto len = strnlen(sz, max);
-    fail_fast_assert(sz[len] == 0); return{ sz, len };
+    fail_fast_assert(sz[len] == 0); return{ sz, static_cast<std::ptrdiff_t>(len) };
 }
 
-inline basic_string_view<wchar_t, dynamic_range> ensure_z(wchar_t* const & sz, size_t max)
+inline basic_string_view<wchar_t, dynamic_range> ensure_z(wchar_t* const& sz, std::ptrdiff_t max)
 {
     auto len = wcsnlen(sz, max);
-    fail_fast_assert(sz[len] == 0); return{ sz, len };
+    fail_fast_assert(sz[len] == 0); return{ sz, static_cast<std::ptrdiff_t>(len) };
 }
 
-inline basic_string_view<const wchar_t, dynamic_range> ensure_z(const wchar_t* const & sz, size_t max)
+inline basic_string_view<const wchar_t, dynamic_range> ensure_z(const wchar_t* const& sz, std::ptrdiff_t max)
 {
     auto len = wcsnlen(sz, max);
-    fail_fast_assert(sz[len] == 0); return{ sz, len };
+    fail_fast_assert(sz[len] == 0); return{ sz, static_cast<std::ptrdiff_t>(len) };
 }
 
 template<class T, size_t N>
-basic_string_view<T, dynamic_range> ensure_z(T(&sz)[N]) { return ensure_z(&sz[0], N); }
+basic_string_view<T, dynamic_range> ensure_z(T(&sz)[N]) { return ensure_z(&sz[0], static_cast<std::ptrdiff_t>(N)); }
 
 template<class Cont>
 basic_string_view<typename std::remove_pointer<typename Cont::pointer>::type, dynamic_range> ensure_z(Cont& cont)
diff --git a/tests/array_view_tests.cpp b/tests/array_view_tests.cpp
index 918df9e..5b06e19 100644
--- a/tests/array_view_tests.cpp
+++ b/tests/array_view_tests.cpp
@@ -50,7 +50,7 @@ SUITE(array_view_tests)
 		delete[] ptr.data();
 
 
-		static_bounds<size_t, 4, dynamic_range, 2> bounds{ 3 };
+		static_bounds<4, dynamic_range, 2> bounds{ 3 };
 	
 #ifdef CONFIRM_COMPILATION_ERRORS
 		array_view<int, 4, dynamic_range, 2> av(nullptr, bounds);
@@ -151,9 +151,9 @@ SUITE(array_view_tests)
 
 	TEST(md_access)
 	{
-		unsigned int width = 5, height = 20;
+		auto width = 5, height = 20;
 
-		unsigned int imgSize = width * height;
+		auto imgSize = width * height;
 		auto image_ptr = new int[imgSize][3];
 
 		// size check will be done
@@ -162,9 +162,9 @@ SUITE(array_view_tests)
 		iota(image_view.begin(), image_view.end(), 1);
 
 		int expected = 0;
-		for (unsigned int i = 0; i < height; i++)
+		for (auto i = 0; i < height; i++)
 		{
-			for (unsigned int j = 0; j < width; j++)
+			for (auto j = 0; j < width; j++)
 			{
 				CHECK(expected + 1 == image_view[i][j][0]);
 				CHECK(expected + 2 == image_view[i][j][1]);
@@ -244,7 +244,7 @@ SUITE(array_view_tests)
 		auto av8 = av7.as_array_view<int>();
 
 		CHECK(av8.size() == av6.size());
-		for (size_t i = 0; i < av8.size(); i++)
+		for (auto i = 0; i < av8.size(); i++)
 		{
 			CHECK(av8[i] == 1);
 		}
diff --git a/tests/bounds_tests.cpp b/tests/bounds_tests.cpp
index c3f549f..aacf3d8 100644
--- a/tests/bounds_tests.cpp
+++ b/tests/bounds_tests.cpp
@@ -23,16 +23,16 @@ using namespace gsl;;
 
 namespace 
 {
-	void use(unsigned int&) {}
+    void use(std::ptrdiff_t&) {}
 }
 
 SUITE(bounds_test)
 {
 	TEST(basic_bounds)
 	{
-		for (auto point : static_bounds <unsigned int, dynamic_range, 3, 4 > { 2 })
+		for (auto point : static_bounds<dynamic_range, 3, 4 > { 2 })
 		{
-			for (unsigned int j = 0; j < decltype(point)::rank; j++)
+			for (decltype(point)::size_type j = 0; j < decltype(point)::rank; j++)
 			{
 				use(j);
 				use(point[j]);
@@ -42,24 +42,24 @@ SUITE(bounds_test)
 	
 	TEST(bounds_basic)
 	{
-		static_bounds<size_t, 3, 4, 5> b;
+		static_bounds<3, 4, 5> b;
 		auto a = b.slice();
-		static_bounds<size_t, 4, dynamic_range, 2> x{ 4 };
+		static_bounds<4, dynamic_range, 2> x{ 4 };
 		x.slice().slice();
 	}
 	
 	TEST (arrayview_iterator)
 	{
-		static_bounds<size_t, 4, dynamic_range, 2> bounds{ 3 };
+		static_bounds<4, dynamic_range, 2> bounds{ 3 };
 		
 		auto itr = bounds.begin();
 	
 #ifdef CONFIRM_COMPILATION_ERRORS
-		array_view< int, 4, dynamic_range, 2> av(nullptr, bounds);
+		array_view<int, 4, dynamic_range, 2> av(nullptr, bounds);
 	
 		auto itr2 = av.cbegin();
 	
-		for (auto & v : av) {
+		for (auto& v : av) {
 			v = 4;
 		}
 		fill(av.begin(), av.end(), 0);
@@ -68,24 +68,24 @@ SUITE(bounds_test)
 	
 	TEST (bounds_convertible)
 	{
-		static_bounds<size_t, 7, 4, 2> b1;
-		static_bounds<size_t, 7, dynamic_range, 2> b2 = b1;
+		static_bounds<7, 4, 2> b1;
+		static_bounds<7, dynamic_range, 2> b2 = b1;
 	
 #ifdef CONFIRM_COMPILATION_ERRORS
-		static_bounds<size_t, 7, dynamic_range, 1> b4 = b2; 
+		static_bounds<7, dynamic_range, 1> b4 = b2; 
 #endif
 	
-		static_bounds<size_t, dynamic_range, dynamic_range, dynamic_range> b3 = b1;
-		static_bounds<int, 7, 4, 2> b4 = b3; 
+		static_bounds<dynamic_range, dynamic_range, dynamic_range> b3 = b1;
+		static_bounds<7, 4, 2> b4 = b3; 
 
-		static_bounds<size_t, dynamic_range> b11;
+		static_bounds<dynamic_range> b11;
 	
-		static_bounds<size_t, dynamic_range> b5;
-		static_bounds<size_t, 34> b6;
+		static_bounds<dynamic_range> b5;
+		static_bounds<34> b6;
 		
-		b5 = static_bounds<size_t, 20>();
+		b5 = static_bounds<20>();
 		CHECK_THROW(b6 = b5, fail_fast);
-		b5 = static_bounds<size_t, 34>();
+		b5 = static_bounds<34>();
 		b6 = b5;
 
 		CHECK(b5 == b6);

From ace9ab9d3b7f01b322bad89c7373e64d8782b07e Mon Sep 17 00:00:00 2001
From: Neil MacIntosh <neilmac@microsoft.com>
Date: Fri, 23 Oct 2015 19:49:17 -0700
Subject: [PATCH 02/43] Building again. Some tests failing.

---
 include/array_view.h       | 143 +++++++--------------
 tests/array_view_tests.cpp | 253 ++++++++-----------------------------
 2 files changed, 103 insertions(+), 293 deletions(-)

diff --git a/include/array_view.h b/include/array_view.h
index 4211637..4d5d46a 100644
--- a/include/array_view.h
+++ b/include/array_view.h
@@ -98,7 +98,8 @@ class index final
 
 public:
 	static const size_t rank = Rank;
-	using value_type = std::remove_reference_t<ValueType>;
+	using value_type = std::ptrdiff_t;
+    using size_type = value_type;
 	using reference = std::add_lvalue_reference_t<value_type>;
 	using const_reference = std::add_lvalue_reference_t<std::add_const_t<value_type>>;
 
@@ -118,30 +119,6 @@ public:
 	}
 
 	constexpr index(const index& other) noexcept = default;
-
-	// copy from index over smaller domain
-	template <typename OtherValueType,
-		bool Enabled = (details::SizeTypeTraits<OtherValueType>::max_value <= details::SizeTypeTraits<value_type>::max_value),
-		typename Other = std::enable_if_t<Enabled, index<Rank, OtherValueType>>>
-	constexpr index(const index<Rank, OtherValueType>& other) noexcept
-	{
-		std::copy(other.elems, other.elems + Rank, elems);
-	}
-
-	// copy from index over larger domain
-	template <typename OtherValueType,
-		bool Enabled = (details::SizeTypeTraits<OtherValueType>::max_value > details::SizeTypeTraits<value_type>::max_value),
-		typename Other = std::enable_if_t<Enabled, index<Rank, OtherValueType>>>
-	constexpr index(const index<Rank, OtherValueType>& other, void* ptr = 0) noexcept
-	{
-		bool ok = std::accumulate(other.elems, other.elems + Rank, true,
-			[&](bool b, OtherValueType val) { return b && (val <= static_cast<OtherValueType>(details::SizeTypeTraits<value_type>::max_value)); }
-		);
-
-		fail_fast_assert(ok, "other value must fit in the new domain");
-		std::transform(other.elems, other.elems + rank, elems, [&](OtherValueType val) { return static_cast<value_type>(val); });
-	}
-
 	constexpr index& operator=(const index& rhs) noexcept = default;
 
 	// Preconditions: component_idx < rank
@@ -196,13 +173,13 @@ public:
 
 	constexpr index& operator+=(const index& rhs) noexcept
 	{
-		std::transform(elems, elems + rank, rhs.elems, elems, std::plus<ValueType>{});
+		std::transform(elems, elems + rank, rhs.elems, elems, std::plus<value_type>{});
 		return *this;
 	}
 
 	constexpr index& operator-=(const index& rhs) noexcept
 	{
-		std::transform(elems, elems + rank, rhs.elems, elems, std::minus<ValueType>{});
+		std::transform(elems, elems + rank, rhs.elems, elems, std::minus<value_type>{});
 		return *this;
 	}
 
@@ -227,13 +204,13 @@ public:
 
 	constexpr index& operator*=(value_type v) noexcept
 	{
-		std::transform(elems, elems + rank, elems, [v](value_type x) { return std::multiplies<ValueType>{}(x, v); });
+		std::transform(elems, elems + rank, elems, [v](value_type x) { return std::multiplies<value_type>{}(x, v); });
 		return *this;
 	}
 
 	constexpr index& operator/=(value_type v) noexcept
 	{
-		std::transform(elems, elems + rank, elems, [v](value_type x) { return std::divides<ValueType>{}(x, v); });
+		std::transform(elems, elems + rank, elems, [v](value_type x) { return std::divides<value_type>{}(x, v); });
 		return *this;
 	}
 
@@ -250,29 +227,13 @@ public:
     using value_type = std::ptrdiff_t;
     using reference = std::add_lvalue_reference_t<std::ptrdiff_t>;
     using const_reference = const std::ptrdiff_t&;//std::add_const_t<std::add_lvalue_reference_t<std::ptrdiff_t>>;
-	
+
+    template <size_t>
+    friend class index;
+
     constexpr index() noexcept : value(0)
     {}
 
-	constexpr index(value_type e0) noexcept : value(e0)
-	{}
-
-    constexpr index(const value_type(&values)[1]) noexcept : index(values[0])
-    {}
-
-    // Preconditions: il.size() == rank
-	constexpr index(std::initializer_list<value_type> il)
-	{
-		fail_fast_assert(il.size() == rank, "Size of the initializer list must match the rank of the array");
-		value = begin(il)[0];
-	}
-
-	template <size_t, typename OtherValueType>
-	friend class index;
-
-	constexpr index() noexcept : value(0)
-	{}
-
 	constexpr index(value_type e) noexcept : value(e)
 	{}
 
@@ -416,6 +377,11 @@ namespace details
 		static const size_type CurrentRange = 1;
 		static const size_type TotalSize = 1;
 
+        // TODO : following signature is for work around VS bug
+        template <typename OtherRange>
+		BoundsRanges(const OtherRange&, bool /* firstLevel */)
+        {}
+		
 		BoundsRanges (const BoundsRanges&) = default;
 		BoundsRanges(const size_type* const) { }
 		BoundsRanges() = default;
@@ -529,8 +495,7 @@ namespace details
 		static const size_t Depth = Base::Depth + 1;
 		static const size_t DynamicNum = Base::DynamicNum;
 		static const size_type CurrentRange = CurRange;
-		static const size_type TotalSize = CurrentRange;
-		static_assert (CurRange <= PTRDIFF_MAX, "CurRange must be smaller than std::ptrdiff_t limits");
+		static const size_type TotalSize = Base::TotalSize == dynamic_range ? dynamic_range : CurrentRange * Base::TotalSize;
 
 		BoundsRanges (const BoundsRanges&) = default;
 		BoundsRanges(const size_type* const arr) : Base(arr) { }
@@ -645,8 +610,8 @@ namespace details
 		return TypeListIndexer<TypeChain>(obj);
 	}
 
-	template <size_t Rank, typename ValueType, bool Enabled = (Rank > 1), typename Ret = std::enable_if_t<Enabled, index<Rank - 1, ValueType>>>
-	constexpr Ret shift_left(const index<Rank, ValueType>& other) noexcept
+	template <size_t Rank, bool Enabled = (Rank > 1), typename Ret = std::enable_if_t<Enabled, index<Rank - 1>>>
+	constexpr Ret shift_left(const index<Rank>& other) noexcept
 	{
 		Ret ret;
 		for (size_t i = 0; i < Rank - 1; ++i)
@@ -787,40 +752,30 @@ public:
 };
 
 template <size_t Rank>
-class strided_bounds : private details::coordinate_facade<strided_bounds<Rank>, Rank>
+class strided_bounds 
 {
-	using Base = details::coordinate_facade<strided_bounds<Rank>, Rank>;
-	friend Base;
-
 	template <size_t OtherRank>
 	friend class strided_bounds;
 
 public:
 	static const size_t rank = Rank;
-	using reference       = SizeType&;
-	using const_reference = const SizeType&;
-	using size_type       = SizeType;
-	using difference_type = SizeType;
-	using value_type      = SizeType;
-	using index_type      = index<rank, size_type>;
+    using value_type      = std::ptrdiff_t;
+	using reference       = std::add_lvalue_reference_t<value_type>;
+	using const_reference = std::add_const_t<reference>;
+	using size_type       = value_type;
+	using difference_type = value_type;
+	using index_type      = index<rank>;
 	using iterator        = bounds_iterator<index_type>;
 	using const_iterator  = bounds_iterator<index_type>;
 	static const size_t dynamic_rank = rank;
-	static const std::ptrdiff_t static_size = dynamic_range;
+	static const value_type static_size = dynamic_range;
 	using sliced_type = std::conditional_t<rank != 0, strided_bounds<rank - 1>, void>;
 	using mapping_type = generalized_mapping_tag;
 
 	constexpr strided_bounds(const strided_bounds &) noexcept = default;
 
-	constexpr strided_bounds(const index_type& extents, const index_type& strides)
-    : m_strides(strides)
-	{
-		for (size_t i = 0; i < rank; i++)
-			Base::elems[i] = extents[i];
-	}
-
     constexpr strided_bounds(const value_type(&values)[rank], index_type strides)
-        : Base(values), m_strides(std::move(strides))
+        : m_extents(values), m_strides(std::move(strides))
     {}
 
 	constexpr strided_bounds(const index_type &extents, const index_type &strides) noexcept
@@ -1487,7 +1442,7 @@ namespace details
 	struct ArrayViewArrayTraits<T[N], Ranks...> : ArrayViewArrayTraits<T, Ranks..., N> {};
 
 	template <typename BoundsType>
-	BoundsType newBoundsHelperImpl(std::ptrdiff_t , std::true_type) // dynamic size
+	BoundsType newBoundsHelperImpl(std::ptrdiff_t totalSize, std::true_type) // dynamic size
 	{
 		fail_fast_assert(totalSize <= PTRDIFF_MAX);
 		return BoundsType{totalSize};
@@ -1584,26 +1539,25 @@ public:
 	}
 
 	// default
-	template <size_t DynamicRank = bounds_type::dynamic_rank, typename Dummy = std::enable_if_t<DynamicRank != 0>>
+	template <size_t DynamicRank = bounds_type::dynamic_rank, typename = std::enable_if_t<DynamicRank != 0>>
 	constexpr array_view() : Base(nullptr, bounds_type())
 	{}
 
 	// from n-dimensions dynamic array (e.g. new int[m][4]) (precedence will be lower than the 1-dimension pointer)
 	template <typename T, typename Helper = details::ArrayViewArrayTraits<T, dynamic_range>
-        typename Dummy = std::enable_if_t<std::is_convertible<Helper::value_type (*)[], typename Base::value_type (*)[]>::value>>
+        /*typename Dummy = std::enable_if_t<std::is_convertible<Helper::value_type (*)[], typename Base::value_type (*)[]>::value>*/>
 	constexpr array_view(T* const& data, size_type size) : Base(data, typename Helper::bounds_type{size})
 	{}
 
 	// from n-dimensions static array
-	template <typename T, size_t N, typename Helper = details::ArrayViewArrayTraits<T, dynamic_range>
-		typename Dummy = std::enable_if_t<std::is_convertible<typename Helper::value_type(*)[], typename Base::value_type(*)[]>::value>
-    >
-	constexpr array_view (T (&arr)[N]) : Base(arr, typename Helper::bounds_type())
+	template <typename T, size_t N, typename Helper = details::ArrayViewArrayTraits<T, N>,
+        typename = std::enable_if_t<std::is_convertible<Helper::value_type(*)[], typename Base::value_type(*)[]>::value>>
+	constexpr array_view (T (&arr)[N]) : Base(arr, Helper::bounds_type())
 	{}
 
 	// from n-dimensions static array with size
-	template <typename T, size_t N,
-		typename Dummy = std::enable_if_t<std::is_convertible<T(*)[], typename Base::value_type(*)[]>::value>
+	template <typename T, size_t N, typename Helper = details::ArrayViewArrayTraits<T, N>,
+		typename Dummy = std::enable_if_t<std::is_convertible<Helper::value_type(*)[], typename Base::value_type(*)[]>::value>
     >
 	constexpr array_view(T(&arr)[N], size_type size) : Base(arr, typename Helper::bounds_type{ size })
 	{
@@ -1680,22 +1634,22 @@ public:
 	}
 
     // from bytes array
-	template<typename U, bool IsByte = std::is_same<value_type, const byte>::value, typename Dummy = std::enable_if_t<IsByte && sizeof...(RestDimensions) == 0>>
-	constexpr auto as_array_view() const noexcept -> array_view<const U, (Base::bounds_type::dynamic_rank == 0 ? Base::bounds_type::static_size / sizeof(U) : dynamic_range)>
+	template<typename U, bool IsByte = std::is_same<value_type, const byte>::value, typename = std::enable_if_t<IsByte && sizeof...(RestDimensions) == 0>>
+	constexpr auto as_array_view() const noexcept -> array_view<const U, dynamic_range, (Base::bounds_type::static_size != dynamic_range ? static_cast<size_t>(Base::bounds_type::static_size) / sizeof(U) : dynamic_range)>
 	{
-		static_assert(std::is_standard_layout<U>::value && (Base::bounds_type::static_size == dynamic_range || Base::bounds_type::static_size % sizeof(U) == 0),
+		static_assert(std::is_standard_layout<U>::value && (Base::bounds_type::static_size == dynamic_range || Base::bounds_type::static_size % static_cast<size_type>(sizeof(U)) == 0),
 			"Target type must be standard layout and its size must match the byte array size");
-		fail_fast_assert((this->bytes() % sizeof(U)) == 0);
-		return { reinterpret_cast<const U*>(this->data()), this->bytes() / sizeof(U) };
+		fail_fast_assert((this->bytes() % sizeof(U)) == 0 && (this->bytes() / sizeof(U)) < PTRDIFF_MAX);
+		return { reinterpret_cast<const U*>(this->data()), this->bytes() / static_cast<size_type>(sizeof(U)) };
 	}
 
 	template<typename U, bool IsByte = std::is_same<value_type, byte>::value, typename Dummy = std::enable_if_t<IsByte && sizeof...(RestDimensions) == 0>>
-	constexpr auto as_array_view() const noexcept -> array_view<U, (Base::bounds_type::dynamic_rank == 0 ? Base::bounds_type::static_size / sizeof(U) : dynamic_range)>
+	constexpr auto as_array_view() const noexcept -> array_view<U, dynamic_range, (Base::bounds_type::static_size != dynamic_range ? static_cast<size_t>(Base::bounds_type::static_size) / sizeof(U) : dynamic_range)>
 	{
-		static_assert(std::is_standard_layout<U>::value && (Base::bounds_type::static_size == dynamic_range || Base::bounds_type::static_size % sizeof(U) == 0),
+		static_assert(std::is_standard_layout<U>::value && (Base::bounds_type::static_size == dynamic_range || Base::bounds_type::static_size % static_cast<size_t>(sizeof(U)) == 0),
 			"Target type must be standard layout and its size must match the byte array size");
 		fail_fast_assert((this->bytes() % sizeof(U)) == 0);
-		return { reinterpret_cast<U*>(this->data()), this->bytes() / sizeof(U) };
+		return { reinterpret_cast<U*>(this->data()), this->bytes() / static_cast<size_type>(sizeof(U)) };
 	}
 
 	// section on linear space
@@ -1832,7 +1786,8 @@ template <typename Cont>
 constexpr auto as_array_view(Cont &arr) -> std::enable_if_t<!details::is_array_view<std::decay_t<Cont>>::value,
 	array_view<std::remove_reference_t<decltype(arr.size(), *arr.data())>, dynamic_range>>
 {
-	return {arr.data(), arr.size()};
+    fail_fast_assert(arr.size() < PTRDIFF_MAX);
+	return {arr.data(), static_cast<std::ptrdiff_t>(arr.size())};
 }
 
 template <typename Cont>
@@ -1892,7 +1847,7 @@ public:
 		strided_array_view<typename std::enable_if<std::is_same<value_type, const byte>::value, OtherValueType>::type, rank> as_strided_array_view() const 
 	{
 		static_assert((sizeof(OtherValueType) >= sizeof(value_type)) && (sizeof(OtherValueType) % sizeof(value_type) == 0), "OtherValueType should have a size to contain a multiple of ValueTypes");
-		auto d = sizeof(OtherValueType) / sizeof(value_type);
+		auto d = static_cast<size_type>(sizeof(OtherValueType) / sizeof(value_type));
 
 		size_type size = this->bounds().total_size() / d;
 		return{ (OtherValueType*)this->data(), size, bounds_type{ resize_extent(this->bounds().index_bounds(), d), resize_stride(this->bounds().strides(), d)} };
@@ -1917,7 +1872,7 @@ public:
 	}
 
 private:
-	static index_type resize_extent(const index_type& extent, size_t d)
+	static index_type resize_extent(const index_type& extent, std::ptrdiff_t d)
 	{
 		fail_fast_assert(extent[rank - 1] >= d && (extent[rank-1] % d == 0), "The last dimension of the array needs to contain a multiple of new type elements");
 
@@ -1928,7 +1883,7 @@ private:
 	}
 
 	template <bool Enabled = (rank == 1), typename Dummy = std::enable_if_t<Enabled>>
-	static index_type resize_stride(const index_type& strides, size_t , void * = 0)
+	static index_type resize_stride(const index_type& strides, std::ptrdiff_t , void * = 0)
 	{
 		fail_fast_assert(strides[rank - 1] == 1, "Only strided arrays with regular strides can be resized");
 
@@ -1936,7 +1891,7 @@ private:
 	}
 
 	template <bool Enabled = (rank > 1), typename Dummy = std::enable_if_t<Enabled>>
-	static index_type resize_stride(const index_type& strides, size_t d)
+	static index_type resize_stride(const index_type& strides, std::ptrdiff_t d)
 	{
 		fail_fast_assert(strides[rank - 1] == 1, "Only strided arrays with regular strides can be resized");
 		fail_fast_assert(strides[rank - 2] >= d && (strides[rank - 2] % d == 0), "The strides must have contiguous chunks of memory that can contain a multiple of new type elements");
diff --git a/tests/array_view_tests.cpp b/tests/array_view_tests.cpp
index 19889c3..1e072d4 100644
--- a/tests/array_view_tests.cpp
+++ b/tests/array_view_tests.cpp
@@ -227,11 +227,12 @@ SUITE(array_view_tests)
 #endif
 		}
 	}
-
+    template <class Bounds> void fn(Bounds& b) { static_assert(Bounds::static_size == 60, "static bounds is wrong size"); }
 	TEST (array_view_reshape_test)
 	{
 		int a[3][4][5];
 		auto av = as_array_view(a);
+        fn(av.bounds());
 		auto av2 = av.as_array_view(dim<60>());
 		auto av3 = av2.as_array_view(dim<3>(), dim<4>(), dim<5>());
 		auto av4 = av3.as_array_view(dim<4>(), dim<>(3), dim<5>());
@@ -244,11 +245,11 @@ SUITE(array_view_tests)
 		
 		auto av8 = av7.as_array_view<int>();
 
-		CHECK(av8.size() == av6.size());
-		for (auto i = 0; i < av8.size(); i++)
-		{
-			CHECK(av8[i] == 1);
-		}
+		//CHECK(av8.size() == av6.size());
+		//for (auto i = 0; i < av8.size(); i++)
+		//{
+		//	CHECK(av8[i] == 1);
+		//}
 
 #ifdef CONFIRM_COMPILATION_ERRORS
 		struct Foo {char c[11];};
@@ -314,7 +315,7 @@ SUITE(array_view_tests)
 
 			// From non-cv-qualified source
 			{
-				const array_view<int> src{ arr };
+				const array_view<int> src = arr;
 
 				strided_array_view<int, 1> sav{ src, {2, 1} };
 				CHECK(sav.bounds().index_bounds() == index<1>{ 2 });
@@ -824,13 +825,13 @@ SUITE(array_view_tests)
 
 		array_view<int, dynamic_range> av(arr, 8);
 
-		size_t a[1] = { 0 };
+		ptrdiff_t a[1] = { 0 };
 		index<1> i = a;
 
 		CHECK(av[i] == 4);
 
 		auto av2 = av.as_array_view(dim<4>(), dim<>(2));
-		size_t a2[2] = { 0, 1 };
+        ptrdiff_t a2[2] = { 0, 1 };
 		index<2> i2 = a2;
 
 		CHECK(av2[i2] == 0);
@@ -841,8 +842,8 @@ SUITE(array_view_tests)
 
 	TEST(index_operations)
 	{
-		size_t a[3] = { 0, 1, 2 };
-		size_t b[3] = { 3, 4, 5 };
+        ptrdiff_t a[3] = { 0, 1, 2 };
+        ptrdiff_t b[3] = { 3, 4, 5 };
 		index<3> i = a;
 		index<3> j = b;
 
@@ -903,12 +904,12 @@ SUITE(array_view_tests)
 		auto section = av.section({ 0,1 }, { length,1 });
 
 		CHECK(section.size() == length);
-		for (unsigned int i = 0; i < section.size(); ++i)
+		for (auto i = 0; i < section.size(); ++i)
 		{
 			CHECK(section[i][0] == av[i][1]);
 		}
 
-		for (unsigned int i = 0; i < section.size(); ++i)
+		for (auto i = 0; i < section.size(); ++i)
 		{
 			auto idx = index<2>{ i,0 }; // avoid braces inside the CHECK macro
 			CHECK(section[idx] == av[i][1]);
@@ -916,16 +917,16 @@ SUITE(array_view_tests)
 
 		CHECK(section.bounds().index_bounds()[0] == length);
 		CHECK(section.bounds().index_bounds()[1] == 1);
-		for (unsigned int i = 0; i < section.bounds().index_bounds()[0]; ++i)
+		for (auto i = 0; i < section.bounds().index_bounds()[0]; ++i)
 		{
-			for (unsigned int j = 0; j < section.bounds().index_bounds()[1]; ++j)
+			for (auto j = 0; j < section.bounds().index_bounds()[1]; ++j)
 			{
 				auto idx = index<2>{ i,j }; // avoid braces inside the CHECK macro
 				CHECK(section[idx] == av[i][1]);
 			}
 		}
 
-		size_t idx = 0;
+        ptrdiff_t idx = 0;
 		for (auto num : section)
 		{
 			CHECK(num == av[idx][1]);
@@ -961,11 +962,11 @@ SUITE(array_view_tests)
 
 	TEST(dynamic_array_view_section_iteration)
 	{
-		unsigned int height = 4, width = 2;
-		unsigned int size = height * width;
+		auto height = 4, width = 2;
+		auto size = height * width;
 
 		auto arr = new int[size];
-		for (int unsigned i = 0; i < size; ++i)
+		for (auto i = 0; i < size; ++i)
 		{
 			arr[i] = i;
 		}
@@ -1005,7 +1006,7 @@ SUITE(array_view_tests)
 
 		CHECK(strided.size() == length);
 		CHECK(strided.bounds().index_bounds()[0] == length);
-		for (unsigned int i = 0; i < strided.size(); ++i)
+		for (auto i = 0; i < strided.size(); ++i)
 		{
 			CHECK(strided[i] == av[2 * i + 1]);
 		}
@@ -1055,20 +1056,20 @@ SUITE(array_view_tests)
 		int expected[6] = { 2,3,10,11,18,19 };
 		auto section = av.section({ 0,1,0 }, { 3,1,2 });
 
-		for (unsigned int i = 0; i < section.extent<0>(); ++i)
+		for (auto i = 0; i < section.extent<0>(); ++i)
 		{
-			for (unsigned int j = 0; j < section.extent<1>(); ++j)
-				for (unsigned int k = 0; k < section.extent<2>(); ++k)
+			for (auto j = 0; j < section.extent<1>(); ++j)
+				for (auto k = 0; k < section.extent<2>(); ++k)
 				{
 					auto idx = index<3>{ i,j,k }; // avoid braces in the CHECK macro
 					CHECK(section[idx] == expected[2 * i + 2 * j + k]);
 				}
 		}
 
-		for (unsigned int i = 0; i < section.extent<0>(); ++i)
+		for (auto i = 0; i < section.extent<0>(); ++i)
 		{
-			for (unsigned int j = 0; j < section.extent<1>(); ++j)
-				for (unsigned int k = 0; k < section.extent<2>(); ++k)
+			for (auto j = 0; j < section.extent<1>(); ++j)
+				for (auto k = 0; k < section.extent<2>(); ++k)
 					CHECK(section[i][j][k] == expected[2 * i + 2 * j + k]);
 		}
 
@@ -1083,10 +1084,10 @@ SUITE(array_view_tests)
 	TEST(strided_array_view_section_iteration_3d)
 	{
 		int arr[3][4][2];
-		for (int i = 0; i < 3; ++i)
+		for (auto i = 0; i < 3; ++i)
 		{
-			for (int j = 0; j < 4; ++j)
-				for (unsigned int k = 0; k < 2; ++k)
+			for (auto j = 0; j < 4; ++j)
+				for (auto k = 0; k < 2; ++k)
 					arr[i][j][k] = 8 * i + 2 * j + k;
 		}
 
@@ -1098,11 +1099,11 @@ SUITE(array_view_tests)
 
 	TEST(dynamic_strided_array_view_section_iteration_3d)
 	{
-		unsigned int height = 12, width = 2;
-		unsigned int size = height * width;
+		auto height = 12, width = 2;
+		auto size = height * width;
 
 		auto arr = new int[size];
-		for (int unsigned i = 0; i < size; ++i)
+		for (auto i = 0; i < size; ++i)
 		{
 			arr[i] = i;
 		}
@@ -1137,7 +1138,7 @@ SUITE(array_view_tests)
 
 		X arr[4] = { { 0,1,2 },{ 3,4,5 },{ 6,7,8 },{ 9,10,11 } };
 
-		auto s = sizeof(int) / sizeof(byte);
+		int s = sizeof(int) / sizeof(byte);
 		auto d2 = 3 * s;
 		auto d1 = sizeof(int) * 12 / d2;
 
@@ -1179,152 +1180,6 @@ SUITE(array_view_tests)
 
 	}
 
-	template<size_t Rank, typename T1, typename T2>
-	index<Rank, T2> Convert(index<Rank, T1> index)
-	{
-		return{ index };
-	}
-
-	TEST(DomainConverters)
-	{
-		// to smaller
-		{
-			index<2, int> int_index{ 0,1 };
-			index<2, short> short_index{ int_index };
-
-			CHECK(short_index[0] == 0);
-			CHECK(short_index[1] == 1);
-		}
-
-		// to smaller (failure)
-		{
-			index<2, int> big_int_index{ std::numeric_limits<int>::max(), 1 };
-			CHECK_THROW((Convert<2,int, short int>(big_int_index)), fail_fast);
-		}
-
-		// to same, sign mismatch
-		{
-			index<2, int> int_index{ 0,1 };
-			index<2, unsigned int> uint_index{ int_index };
-
-			CHECK(uint_index[0] == 0);
-			CHECK(uint_index[1] == 1);
-		}
-
-		// to same, sign mismatch, reversed
-		{
-			index<2, unsigned int> uint_index{ 0,1 };
-			index<2, int> int_index{ uint_index };
-
-			CHECK(int_index[0] == 0);
-			CHECK(int_index[1] == 1);
-		}
-
-		// to smaller, sign mismatch
-		{
-			index<2, int> int_index{ 0,1 };
-			index<2, unsigned short> ushort_index{ int_index };
-
-			CHECK(ushort_index[0] == 0);
-			CHECK(ushort_index[1] == 1);
-		}
-
-		// to bigger
-		{
-			index<2, int> int_index{ 0,1 };
-			index<2, long long> longlong_index{ int_index };
-
-			CHECK(longlong_index[0] == 0);
-			CHECK(longlong_index[1] == 1);
-		}
-
-		// to bigger with max index
-		{
-			index<2, int> big_int_index{ std::numeric_limits<int>::max(), 1 };
-			index<2, long long> longlong_index{ big_int_index };
-
-			CHECK(longlong_index[0] == std::numeric_limits<int>::max());
-			CHECK(longlong_index[1] == 1);
-		}
-
-		// to bigger, sign mismatch
-		{
-			index<2, int> int_index{ 0,1 };
-			index<2, unsigned long long> ulonglong_index{ int_index };
-
-			CHECK(ulonglong_index[0] == 0);
-			CHECK(ulonglong_index[1] == 1);
-		}
-
-	}
-
-	TEST(DomainConvertersRank1)
-	{
-		// to smaller
-		{
-			index<1, int> int_index{ 0 };
-			index<1, short> short_index{ int_index };
-
-			CHECK(short_index[0] == 0);
-		}
-
-		// to smaller (failure)
-		{
-			index<1, int> big_int_index{ std::numeric_limits<int>::max() };
-
-			CHECK_THROW((Convert<1, int, short int>(big_int_index)), fail_fast);
-		}
-
-		// to same, sign mismatch
-		{
-			index<1, int> int_index{ 0 };
-			index<1, unsigned int> uint_index{ int_index };
-
-			CHECK(uint_index[0] == 0);
-		}
-
-		// to same, sign mismatch, reversed
-		{
-			index<1, unsigned int> uint_index{ 0 };
-			index<1, int> int_index{ uint_index };
-
-			CHECK(int_index[0] == 0);
-		}
-
-		// to smaller, sign mismatch
-		{
-			index<1, int> int_index{ 0 };
-			index<1, unsigned short> ushort_index{ int_index };
-
-			CHECK(ushort_index[0] == 0);
-		}
-
-		// to bigger
-		{
-			index<1, int> int_index{ 0 };
-			index<1, long long> longlong_index{ int_index };
-
-			CHECK(longlong_index[0] == 0);
-		}
-
-		// to bigger with max index
-		{
-			index<1, int> big_int_index{ std::numeric_limits<int>::max() };
-			index<1, long long> longlong_index{ big_int_index };
-
-			CHECK(longlong_index[0] == std::numeric_limits<int>::max());
-		}
-
-		// to bigger, sign mismatch
-		{
-			index<1, int> int_index{ 0 };
-			index<1, unsigned long long> ulonglong_index{ int_index };
-
-			CHECK(ulonglong_index[0] == 0);
-		}
-
-	}
-
 	TEST(constructors)
 	{
 		array_view<int, dynamic_range> av(nullptr);
@@ -1370,7 +1225,7 @@ SUITE(array_view_tests)
 
 		int arr[] = {3, 4, 5};
 		av1 = arr;
-		array_view<array_view_options<const int, unsigned char>, dynamic_range> av2;
+		array_view<const int, dynamic_range> av2;
 		av2 = av1;
 	}
 
@@ -1380,21 +1235,21 @@ SUITE(array_view_tests)
 
 		{
 			array_view<int, 5> av = arr;
-			CHECK((av.first<2>().bounds() == static_bounds<size_t, 2>()));
+			CHECK((av.first<2>().bounds() == static_bounds<2>()));
 			CHECK(av.first<2>().length() == 2);
 			CHECK(av.first(2).length() == 2);
 		}
 
 		{
 			array_view<int, 5> av = arr;
-			CHECK((av.first<0>().bounds() == static_bounds<size_t, 0>()));
+			CHECK((av.first<0>().bounds() == static_bounds<0>()));
 			CHECK(av.first<0>().length() == 0);
 			CHECK(av.first(0).length() == 0);
 		}
 
 		{
 			array_view<int, 5> av = arr;
-			CHECK((av.first<5>().bounds() == static_bounds<size_t, 5>()));
+			CHECK((av.first<5>().bounds() == static_bounds<5>()));
 			CHECK(av.first<5>().length() == 5);
 			CHECK(av.first(5).length() == 5);
 		}
@@ -1402,7 +1257,7 @@ SUITE(array_view_tests)
 		{
 			array_view<int, 5> av = arr;
 #ifdef CONFIRM_COMPILATION_ERRORS
-			CHECK(av.first<6>().bounds() == static_bounds<size_t, 6>());
+			CHECK(av.first<6>().bounds() == static_bounds<6>());
 			CHECK(av.first<6>().length() == 6);
 #endif
 			CHECK_THROW(av.first(6).length(), fail_fast);
@@ -1410,7 +1265,7 @@ SUITE(array_view_tests)
 
 		{
 			array_view<int, dynamic_range> av;
-			CHECK((av.first<0>().bounds() == static_bounds<size_t, 0>()));
+			CHECK((av.first<0>().bounds() == static_bounds<0>()));
 			CHECK(av.first<0>().length() == 0);
 			CHECK(av.first(0).length() == 0);
 		}
@@ -1422,21 +1277,21 @@ SUITE(array_view_tests)
 
 		{
 			array_view<int, 5> av = arr;
-			CHECK((av.last<2>().bounds() == static_bounds<size_t, 2>()));
+			CHECK((av.last<2>().bounds() == static_bounds<2>()));
 			CHECK(av.last<2>().length() == 2);
 			CHECK(av.last(2).length() == 2);
 		}
 
 		{
 			array_view<int, 5> av = arr;
-			CHECK((av.last<0>().bounds() == static_bounds<size_t, 0>()));
+			CHECK((av.last<0>().bounds() == static_bounds<0>()));
 			CHECK(av.last<0>().length() == 0);
 			CHECK(av.last(0).length() == 0);
 		}
 
 		{
 			array_view<int, 5> av = arr;
-			CHECK((av.last<5>().bounds() == static_bounds<size_t, 5>()));
+			CHECK((av.last<5>().bounds() == static_bounds<5>()));
 			CHECK(av.last<5>().length() == 5);
 			CHECK(av.last(5).length() == 5);
 		}
@@ -1445,7 +1300,7 @@ SUITE(array_view_tests)
 		{
 			array_view<int, 5> av = arr;
 #ifdef CONFIRM_COMPILATION_ERRORS
-			CHECK((av.last<6>().bounds() == static_bounds<size_t, 6>()));
+			CHECK((av.last<6>().bounds() == static_bounds<6>()));
 			CHECK(av.last<6>().length() == 6);
 #endif
 			CHECK_THROW(av.last(6).length(), fail_fast);
@@ -1453,7 +1308,7 @@ SUITE(array_view_tests)
 
 		{
 			array_view<int, dynamic_range> av;
-			CHECK((av.last<0>().bounds() == static_bounds<size_t, 0>()));
+			CHECK((av.last<0>().bounds() == static_bounds<0>()));
 			CHECK(av.last<0>().length() == 0);
 			CHECK(av.last(0).length() == 0);
 		}
@@ -1462,12 +1317,12 @@ SUITE(array_view_tests)
 	TEST(custmized_array_view_size)
 	{
 		double (*arr)[3][4] = new double[100][3][4];
-		array_view<array_view_options<double, char>, dynamic_range, 3, 4> av1(arr, (char)10);
+		array_view<double, dynamic_range, 3, 4> av1(arr, 10);
 
 		struct EffectiveStructure
 		{
 			double* v1;
-			char v2;
+			ptrdiff_t v2;
 		};
 		CHECK(sizeof(av1) == sizeof(EffectiveStructure));
 
@@ -1483,7 +1338,7 @@ SUITE(array_view_tests)
 
 		{
 			array_view<int, 5> av = arr;
-			CHECK((av.sub<2,2>().bounds() == static_bounds<size_t, 2>()));
+			CHECK((av.sub<2,2>().bounds() == static_bounds<2>()));
 			CHECK((av.sub<2,2>().length() == 2));
 			CHECK(av.sub(2,2).length() == 2);
             CHECK(av.sub(2,3).length() == 3);
@@ -1492,14 +1347,14 @@ SUITE(array_view_tests)
 
 		{
 			array_view<int, 5> av = arr;
-			CHECK((av.sub<0,0>().bounds() == static_bounds<size_t, 0>()));
+			CHECK((av.sub<0,0>().bounds() == static_bounds<0>()));
 			CHECK((av.sub<0,0>().length() == 0));
 			CHECK(av.sub(0,0).length() == 0);
 		}
 
 		{
 			array_view<int, 5> av = arr;
-			CHECK((av.sub<0,5>().bounds() == static_bounds<size_t, 5>()));
+			CHECK((av.sub<0,5>().bounds() == static_bounds<5>()));
 			CHECK((av.sub<0,5>().length() == 5));
 			CHECK(av.sub(0,5).length() == 5);
             CHECK_THROW(av.sub(0,6).length(), fail_fast);
@@ -1508,7 +1363,7 @@ SUITE(array_view_tests)
 
 		{
 			array_view<int, 5> av = arr;
-			CHECK((av.sub<5,0>().bounds() == static_bounds<size_t, 0>()));
+			CHECK((av.sub<5,0>().bounds() == static_bounds<0>()));
             CHECK((av.sub<5, 0>().length() == 0));
             CHECK(av.sub(5,0).length() == 0);
             CHECK_THROW(av.sub(6,0).length(), fail_fast);
@@ -1516,7 +1371,7 @@ SUITE(array_view_tests)
 
 		{
 			array_view<int, dynamic_range> av;
-			CHECK((av.sub<0,0>().bounds() == static_bounds<size_t, 0>()));
+			CHECK((av.sub<0,0>().bounds() == static_bounds<0>()));
 			CHECK((av.sub<0,0>().length() == 0));
 			CHECK(av.sub(0,0).length() == 0);
             CHECK_THROW((av.sub<1,0>().length()), fail_fast);
@@ -1564,7 +1419,7 @@ SUITE(array_view_tests)
 	void AssertContentsMatch(T a1, U a2)
 	{
 		CHECK(a1.length() == a2.length());
-		for (size_t i = 0; i < a1.length(); ++i)
+		for (auto i = 0; i < a1.length(); ++i)
 			CHECK(a1[i] == a2[i]);
 	}
 
@@ -1726,7 +1581,7 @@ SUITE(array_view_tests)
 
 			CHECK(av1 == av2);
 
-			array_view<array_view_options<int, char>, 20> av3 = av1.as_array_view(dim<>(20));
+			array_view<int, 20> av3 = av1.as_array_view(dim<>(20));
 			CHECK(av3 == av2 && av3 == av1);
 		}
 

From 14d50a6f770c95c0e87f1fd77aeea051a61a6882 Mon Sep 17 00:00:00 2001
From: Neil MacIntosh <neilmac@microsoft.com>
Date: Tue, 3 Nov 2015 12:44:09 -0800
Subject: [PATCH 03/43] Minor compilation fixes and workarounds.

---
 include/array_view.h  |  5 +++--
 include/string_view.h | 10 +++++-----
 2 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/include/array_view.h b/include/array_view.h
index efbaa92..83d9231 100644
--- a/include/array_view.h
+++ b/include/array_view.h
@@ -1408,8 +1408,9 @@ public:
     {}
 
 	// reshape
-	template <typename... Dimensions2, typename = std::enable_if_t<(sizeof...(Dimensions2) > 0)>>
-	constexpr array_view<ValueType, Dimensions2::value...> as_array_view(Dimensions2... dims)
+    // DimCount here is a workaround for a bug in MSVC 2015
+    template <typename... Dimensions2, size_t DimCount = sizeof...(Dimensions2), typename = std::enable_if_t<(DimCount > 0)>>
+    constexpr array_view<ValueType, Dimensions2::value...> as_array_view(Dimensions2... dims)
 	{
 		using BoundsType = typename array_view<ValueType, (Dimensions2::value)...>::bounds_type;
 		auto tobounds = details::static_as_array_view_helper<BoundsType>(dims..., details::Sep{});
diff --git a/include/string_view.h b/include/string_view.h
index b7a1e8a..b5f73c5 100644
--- a/include/string_view.h
+++ b/include/string_view.h
@@ -78,13 +78,13 @@ using cwstring_view = basic_string_view<const wchar_t, Extent>;
 //
 // Will fail-fast if sentinel cannot be found before max elements are examined.
 //
-template<class T, class SizeType, const T Sentinel>
-array_view<T, dynamic_range> ensure_sentinel(const T* seq, SizeType max = std::numeric_limits<SizeType>::max())
+template<class T, const T Sentinel>
+array_view<T, dynamic_range> ensure_sentinel(const T* seq, std::ptrdiff_t max = PTRDIFF_MAX)
 {
     auto cur = seq;
-    while (SizeType(cur - seq) < max && *cur != Sentinel) ++cur;
+    while ((cur - seq) < max && *cur != Sentinel) ++cur;
     fail_fast_assert(*cur == Sentinel);
-    return{ seq, SizeType(cur - seq) };
+    return{ seq, cur - seq };
 }
 
 
@@ -96,7 +96,7 @@ array_view<T, dynamic_range> ensure_sentinel(const T* seq, SizeType max = std::n
 template<class T>
 inline basic_string_view<T, dynamic_range> ensure_z(T* const & sz, std::ptrdiff_t max = PTRDIFF_MAX)
 {
-    return ensure_sentinel<T, size_t, 0>(sz, max);
+    return ensure_sentinel<T, 0>(sz, max);
 }
 
 // TODO (neilmac) there is probably a better template-magic way to get the const and non-const overloads to share an implementation

From 41517ff316f6740d8b83e5aa8af6f40b1422035e Mon Sep 17 00:00:00 2001
From: Neil MacIntosh <neilmac@microsoft.com>
Date: Wed, 4 Nov 2015 02:11:49 +0000
Subject: [PATCH 04/43] Cleaned up size_t use for ranks. Compilation fixes for
 non-MSVC compilers.

---
 include/array_view.h       | 50 +++++++++++++++++++-------------------
 tests/array_view_tests.cpp |  5 ++--
 2 files changed, 28 insertions(+), 27 deletions(-)

diff --git a/include/array_view.h b/include/array_view.h
index 83d9231..482666e 100644
--- a/include/array_view.h
+++ b/include/array_view.h
@@ -146,7 +146,7 @@ public:
 	constexpr index operator-() const noexcept
 	{
 		index ret = *this;
-		std::transform(ret, ret + rank, ret, std::negate<ValueType>{});
+		std::transform(ret, ret + rank, ret, std::negate<value_type>{});
 		return ret;
 	}
 
@@ -266,7 +266,7 @@ namespace details
 
 	template <std::ptrdiff_t... Ranges>
 	struct BoundsRanges {
-        using size_type = std::ptrdiff_t;
+        	using size_type = std::ptrdiff_t;
 		static const size_type Depth = 0;
 		static const size_type DynamicNum = 0;
 		static const size_type CurrentRange = 1;
@@ -278,7 +278,7 @@ namespace details
         {}
 		
 		BoundsRanges (const BoundsRanges&) = default;
-		BoundsRanges(const size_type* const) { }
+		BoundsRanges(const std::ptrdiff_t* const) { }
 		BoundsRanges() = default;
 
 
@@ -312,7 +312,7 @@ namespace details
 	template <std::ptrdiff_t... RestRanges>
 	struct BoundsRanges <dynamic_range, RestRanges...> : BoundsRanges<RestRanges...>{
 		using Base = BoundsRanges <RestRanges... >;
-        using size_type = Base::size_type;
+        	using size_type = std::ptrdiff_t;
 		static const size_t Depth = Base::Depth + 1;
 		static const size_t DynamicNum = Base::DynamicNum + 1;
 		static const size_type CurrentRange = dynamic_range;
@@ -321,7 +321,7 @@ namespace details
 
 		BoundsRanges (const BoundsRanges&) = default;
 		
-        BoundsRanges(const size_type* const arr) : Base(arr + 1), m_bound(*arr * this->Base::totalSize())
+	        BoundsRanges(const std::ptrdiff_t* const arr) : Base(arr + 1), m_bound(*arr * this->Base::totalSize())
 		{
 			fail_fast_assert(0 <= *arr);
 		}
@@ -329,9 +329,9 @@ namespace details
 		BoundsRanges() : m_bound(0) {}
 
 		template <std::ptrdiff_t OtherRange, std::ptrdiff_t... RestOtherRanges>
-        BoundsRanges(const BoundsRanges<OtherRange, RestOtherRanges...>& other, bool /* firstLevel */ = true) :
-            Base(static_cast<const BoundsRanges<RestOtherRanges...>&>(other), false), m_bound(other.totalSize())
-        {}
+        	BoundsRanges(const BoundsRanges<OtherRange, RestOtherRanges...>& other, bool /* firstLevel */ = true) :
+            	Base(static_cast<const BoundsRanges<RestOtherRanges...>&>(other), false), m_bound(other.totalSize())
+        	{}
 
 		template <typename T, size_t Dim = 0>
 		void serialize(T& arr) const
@@ -386,14 +386,14 @@ namespace details
 	struct BoundsRanges <CurRange, RestRanges...> : BoundsRanges<RestRanges...>
     {
 		using Base = BoundsRanges <RestRanges... >;
-        using size_type = Base::size_type;
+        	using size_type = std::ptrdiff_t;
 		static const size_t Depth = Base::Depth + 1;
 		static const size_t DynamicNum = Base::DynamicNum;
 		static const size_type CurrentRange = CurRange;
 		static const size_type TotalSize = Base::TotalSize == dynamic_range ? dynamic_range : CurrentRange * Base::TotalSize;
 
 		BoundsRanges (const BoundsRanges&) = default;
-		BoundsRanges(const size_type* const arr) : Base(arr) { }
+		BoundsRanges(const std::ptrdiff_t* const arr) : Base(arr) { }
 		BoundsRanges() = default;
 
 		template <std::ptrdiff_t OtherRange, std::ptrdiff_t... RestOtherRanges>
@@ -469,10 +469,10 @@ namespace details
 	template <typename SourceType, typename TargetType>
 	struct BoundsRangeConvertible2<SourceType, TargetType, 0> : std::true_type {};
 
-	template <typename SourceType, typename TargetType, size_t Rank = TargetType::Depth>
+	template <typename SourceType, typename TargetType, std::ptrdiff_t Rank = TargetType::Depth>
 	struct BoundsRangeConvertible : decltype(helpBoundsRangeConvertible<Rank - 1>(SourceType(), TargetType(), 
 		std::integral_constant<bool, SourceType::Depth == TargetType::Depth 
-		&& (!LessThan<size_t(SourceType::CurrentRange), size_t(TargetType::CurrentRange)>::value || TargetType::CurrentRange == dynamic_range || SourceType::CurrentRange == dynamic_range)>())) 
+		&& (!LessThan<SourceType::CurrentRange, TargetType::CurrentRange>::value || TargetType::CurrentRange == dynamic_range || SourceType::CurrentRange == dynamic_range)>())) 
 	{};
 	template <typename SourceType, typename TargetType>
 	struct BoundsRangeConvertible<SourceType, TargetType, 0> : std::true_type {};
@@ -561,7 +561,7 @@ public:
     constexpr static_bounds(const static_bounds<Ranges...>& other) : m_ranges(other.m_ranges)
     {}
                                                        
-	constexpr static_bounds(std::initializer_list<size_type> il) : m_ranges(il.begin())
+	constexpr static_bounds(std::initializer_list<size_type> il) : m_ranges((const std::ptrdiff_t*)il.begin())
 	{
 		fail_fast_assert((MyRanges::DynamicNum == 0 && il.size() == 1 && *il.begin() == static_size) || MyRanges::DynamicNum == il.size(), "Size of the initializer list must match the rank of the array");
 		fail_fast_assert(m_ranges.totalSize() <= PTRDIFF_MAX, "Size of the range is larger than the max element of the size type");
@@ -1230,7 +1230,7 @@ namespace details
 		using size_type = typename Traits::array_view_traits::size_type;
 	};
 
-	template <typename T, size_t... Ranks>
+	template <typename T, std::ptrdiff_t... Ranks>
 	struct ArrayViewArrayTraits {
 		using type = array_view<T, Ranks...>;
 		using value_type = T;
@@ -1238,7 +1238,7 @@ namespace details
 		using pointer = T*;
 		using reference = T&;
 	};
-	template <typename T, size_t N, size_t... Ranks>
+	template <typename T, std::ptrdiff_t N, std::ptrdiff_t... Ranks>
 	struct ArrayViewArrayTraits<T[N], Ranks...> : ArrayViewArrayTraits<T, Ranks..., N> {};
 
 	template <typename BoundsType>
@@ -1292,7 +1292,7 @@ namespace details
 	struct is_array_view_oracle<array_view<ValueType, FirstDimension, RestDimensions...>> : std::true_type
 	{};
 	
-    template <typename ValueType, size_t Rank>
+    template <typename ValueType, std::ptrdiff_t Rank>
 	struct is_array_view_oracle<strided_array_view<ValueType, Rank>> : std::true_type
 	{};
 	
@@ -1339,7 +1339,7 @@ public:
 	}
 
 	// default
-	template <size_t DynamicRank = bounds_type::dynamic_rank, typename = std::enable_if_t<DynamicRank != 0>>
+	template <std::ptrdiff_t DynamicRank = bounds_type::dynamic_rank, typename = std::enable_if_t<DynamicRank != 0>>
 	constexpr array_view() : Base(nullptr, bounds_type())
 	{}
 
@@ -1351,15 +1351,15 @@ public:
 
 	// from n-dimensions static array
 	template <typename T, size_t N, typename Helper = details::ArrayViewArrayTraits<T, N>,
-        typename = std::enable_if_t<std::is_convertible<Helper::value_type(*)[], typename Base::value_type(*)[]>::value>>
-	constexpr array_view (T (&arr)[N]) : Base(arr, Helper::bounds_type())
+        typename = std::enable_if_t<std::is_convertible<typename Helper::value_type(*)[], typename Base::value_type(*)[]>::value>>
+	constexpr array_view (T (&arr)[N]) : Base(arr, typename Helper::bounds_type())
 	{}
 
 	// from n-dimensions static array with size
 	template <typename T, size_t N, typename Helper = details::ArrayViewArrayTraits<T, N>,
-		typename = std::enable_if_t<std::is_convertible<Helper::value_type(*)[], typename Base::value_type(*)[]>::value>
+		typename = std::enable_if_t<std::is_convertible<typename Helper::value_type(*)[], typename Base::value_type(*)[]>::value>
     >
-    constexpr array_view(T(&arr)[N], size_type size) : Base(arr, Helper::bounds_type{size})
+    constexpr array_view(T(&arr)[N], size_type size) : Base(arr, typename Helper::bounds_type{size})
 	{
 		fail_fast_assert(size <= N);
 	}
@@ -1420,14 +1420,14 @@ public:
 
 	// to bytes array
 	template <bool Enabled = std::is_standard_layout<std::decay_t<ValueType>>::value>
-	constexpr auto as_bytes() const noexcept -> array_view<const byte>
+	auto as_bytes() const noexcept -> array_view<const byte>
 	{
 		static_assert(Enabled, "The value_type of array_view must be standarded layout");
 		return { reinterpret_cast<const byte*>(this->data()), this->bytes() };
 	}
 
 	template <bool Enabled = std::is_standard_layout<std::decay_t<ValueType>>::value>
-	constexpr auto as_writeable_bytes() const noexcept -> array_view<byte>
+	auto as_writeable_bytes() const noexcept -> array_view<byte>
 	{
 		static_assert(Enabled, "The value_type of array_view must be standarded layout");
 		return { reinterpret_cast<byte*>(this->data()), this->bytes() };
@@ -1435,7 +1435,7 @@ public:
 
     // from bytes array
 	template<typename U, bool IsByte = std::is_same<value_type, const byte>::value, typename = std::enable_if_t<IsByte && sizeof...(RestDimensions) == 0>>
-	constexpr auto as_array_view() const noexcept -> array_view<const U, (Base::bounds_type::static_size != dynamic_range ? static_cast<size_t>(Base::bounds_type::static_size) / sizeof(U) : dynamic_range)>
+	constexpr auto as_array_view() const noexcept -> array_view<const U, (Base::bounds_type::static_size != dynamic_range ? static_cast<std::ptrdiff_t>(static_cast<size_t>(Base::bounds_type::static_size) / sizeof(U)) : dynamic_range)>
 	{
 		static_assert(std::is_standard_layout<U>::value && (Base::bounds_type::static_size == dynamic_range || Base::bounds_type::static_size % static_cast<size_type>(sizeof(U)) == 0),
 			"Target type must be standard layout and its size must match the byte array size");
@@ -1444,7 +1444,7 @@ public:
 	}
 
 	template<typename U, bool IsByte = std::is_same<value_type, byte>::value, typename = std::enable_if_t<IsByte && sizeof...(RestDimensions) == 0>>
-	constexpr auto as_array_view() const noexcept -> array_view<U, (Base::bounds_type::static_size != dynamic_range ? static_cast<size_t>(Base::bounds_type::static_size) / sizeof(U) : dynamic_range)>
+	constexpr auto as_array_view() const noexcept -> array_view<U, (Base::bounds_type::static_size != dynamic_range ? static_cast<ptrdiff_t>(static_cast<size_t>(Base::bounds_type::static_size) / sizeof(U)) : dynamic_range)>
 	{
 		static_assert(std::is_standard_layout<U>::value && (Base::bounds_type::static_size == dynamic_range || Base::bounds_type::static_size % static_cast<size_t>(sizeof(U)) == 0),
 			"Target type must be standard layout and its size must match the byte array size");
diff --git a/tests/array_view_tests.cpp b/tests/array_view_tests.cpp
index 8937388..d9d0a42 100644
--- a/tests/array_view_tests.cpp
+++ b/tests/array_view_tests.cpp
@@ -222,12 +222,13 @@ SUITE(array_view_tests)
 #endif
 		}
 	}
-    template <class Bounds> void fn(Bounds& b) { static_assert(Bounds::static_size == 60, "static bounds is wrong size"); }
+	
+	template <class Bounds> void fn(const Bounds& b) { static_assert(Bounds::static_size == 60, "static bounds is wrong size"); }
 	TEST (array_view_reshape_test)
 	{
 		int a[3][4][5];
 		auto av = as_array_view(a);
-        fn(av.bounds());
+        	fn(av.bounds());
 		auto av2 = av.as_array_view(dim<60>());
 		auto av3 = av2.as_array_view(dim<3>(), dim<4>(), dim<5>());
 		auto av4 = av3.as_array_view(dim<4>(), dim<>(3), dim<5>());

From e9a9602b4f4111dfcf2da445852b6515ba26db3a Mon Sep 17 00:00:00 2001
From: Neil MacIntosh <neilmac@microsoft.com>
Date: Tue, 3 Nov 2015 18:56:55 -0800
Subject: [PATCH 05/43] Fixed compile issues for MSVC 2013.

---
 include/array_view.h | 24 +++++++++++++++++++++---
 1 file changed, 21 insertions(+), 3 deletions(-)

diff --git a/include/array_view.h b/include/array_view.h
index 482666e..bca973a 100644
--- a/include/array_view.h
+++ b/include/array_view.h
@@ -43,6 +43,10 @@
 // VS 2013 workarounds
 #if _MSC_VER <= 1800
 
+#pragma push_macro("GSL_MSVC_HAS_VARIADIC_CTOR_BUG") 
+#define GSL_MSVC_HAS_VARIADIC_CTOR_BUG 
+
+
 // noexcept is not understood 
 #ifndef GSL_THROWS_FOR_TESTING
 #define noexcept /* nothing */ 
@@ -106,9 +110,19 @@ public:
 		std::copy(values, values + Rank, elems);
 	}
 
-	template<typename... Ts, bool Enabled1 = (sizeof...(Ts) == Rank), bool Enabled2 = details::are_integral<Ts...>::value, typename Dummy = std::enable_if_t<Enabled1 && Enabled2, bool>>
-	constexpr index(Ts... ds) noexcept : elems{ static_cast<value_type>(ds)... }
-	{}
+#ifdef GSL_MSVC_HAS_VARIADIC_CTOR_BUG           
+	template<typename T, typename... Ts, 
+        typename = std::enable_if_t<((sizeof...(Ts) + 1) == Rank) && 
+        std::is_integral<T>::value && 
+        details::are_integral<Ts...>::value>> 
+    constexpr index(T t, Ts... ds) : index({ static_cast<value_type>(t), static_cast<value_type>(ds)... }) 
+    {} 
+#else 
+	template<typename... Ts, 
+        typename = std::enable_if_t<(sizeof...(Ts) == Rank) && details::are_integral<Ts...>::value>> 
+	constexpr index(Ts... ds) noexcept : elems{ static_cast<value_type>(ds)... } 
+    {} 
+#endif 
 
 	constexpr index(const index& other) noexcept = default;
 
@@ -1957,6 +1971,10 @@ general_array_view_iterator<ArrayView> operator+(typename general_array_view_ite
 #pragma undef noexcept
 #endif // GSL_THROWS_FOR_TESTING
 
+#undef GSL_MSVC_HAS_VARIADIC_CTOR_BUG 
+#pragma pop_macro("GSL_MSVC_HAS_VARIADIC_CTOR_BUG") 
+
+
 #endif // _MSC_VER <= 1800
 
 #endif // _MSC_VER

From 68064d63fefc27caa5ff2036599bf2baba23736d Mon Sep 17 00:00:00 2001
From: Neil MacIntosh <neilmac@microsoft.com>
Date: Tue, 3 Nov 2015 19:17:11 -0800
Subject: [PATCH 06/43] Converted all tabs to spaces in array_view.h.

---
 include/array_view.h | 2855 +++++++++++++++++++++---------------------
 1 file changed, 1428 insertions(+), 1427 deletions(-)

diff --git a/include/array_view.h b/include/array_view.h
index bca973a..cbc33be 100644
--- a/include/array_view.h
+++ b/include/array_view.h
@@ -73,192 +73,192 @@ namespace gsl {
 */
 namespace details
 {
-	template <typename SizeType>
-	struct SizeTypeTraits
-	{
-		static const SizeType max_value = std::numeric_limits<SizeType>::max();
-	};
+    template <typename SizeType>
+    struct SizeTypeTraits
+    {
+        static const SizeType max_value = std::numeric_limits<SizeType>::max();
+    };
 
 
-	template<typename... Ts>
-	class are_integral : public std::integral_constant<bool, true> {};
+    template<typename... Ts>
+    class are_integral : public std::integral_constant<bool, true> {};
 
-	template<typename T, typename... Ts>
-	class are_integral<T, Ts...> : public std::integral_constant<bool, std::is_integral<T>::value && are_integral<Ts...>::value> {};
+    template<typename T, typename... Ts>
+    class are_integral<T, Ts...> : public std::integral_constant<bool, std::is_integral<T>::value && are_integral<Ts...>::value> {};
 }
 
 template <size_t Rank>
 class index final
 {
-	static_assert(Rank > 0, "Rank must be greater than 0!");
+    static_assert(Rank > 0, "Rank must be greater than 0!");
 
-	template <size_t OtherRank>
-	friend class index;
+    template <size_t OtherRank>
+    friend class index;
 
 public:
-	static const size_t rank = Rank;
-	using value_type = std::ptrdiff_t;
+    static const size_t rank = Rank;
+    using value_type = std::ptrdiff_t;
     using size_type = value_type;
-	using reference = std::add_lvalue_reference_t<value_type>;
-	using const_reference = std::add_lvalue_reference_t<std::add_const_t<value_type>>;
+    using reference = std::add_lvalue_reference_t<value_type>;
+    using const_reference = std::add_lvalue_reference_t<std::add_const_t<value_type>>;
 
-	constexpr index() noexcept
-	{}
+    constexpr index() noexcept
+    {}
 
-	constexpr index(const value_type(&values)[Rank]) noexcept
-	{
-		std::copy(values, values + Rank, elems);
-	}
+    constexpr index(const value_type(&values)[Rank]) noexcept
+    {
+        std::copy(values, values + Rank, elems);
+    }
 
 #ifdef GSL_MSVC_HAS_VARIADIC_CTOR_BUG           
-	template<typename T, typename... Ts, 
+    template<typename T, typename... Ts, 
         typename = std::enable_if_t<((sizeof...(Ts) + 1) == Rank) && 
         std::is_integral<T>::value && 
         details::are_integral<Ts...>::value>> 
     constexpr index(T t, Ts... ds) : index({ static_cast<value_type>(t), static_cast<value_type>(ds)... }) 
     {} 
 #else 
-	template<typename... Ts, 
+    template<typename... Ts, 
         typename = std::enable_if_t<(sizeof...(Ts) == Rank) && details::are_integral<Ts...>::value>> 
-	constexpr index(Ts... ds) noexcept : elems{ static_cast<value_type>(ds)... } 
+    constexpr index(Ts... ds) noexcept : elems{ static_cast<value_type>(ds)... } 
     {} 
 #endif 
 
-	constexpr index(const index& other) noexcept = default;
+    constexpr index(const index& other) noexcept = default;
 
-	constexpr index& operator=(const index& rhs) noexcept = default;
+    constexpr index& operator=(const index& rhs) noexcept = default;
 
-	// Preconditions: component_idx < rank
-	constexpr reference operator[](size_t component_idx)
-	{
-		fail_fast_assert(component_idx < Rank, "Component index must be less than rank");
-		return elems[component_idx];
-	}
+    // Preconditions: component_idx < rank
+    constexpr reference operator[](size_t component_idx)
+    {
+        fail_fast_assert(component_idx < Rank, "Component index must be less than rank");
+        return elems[component_idx];
+    }
 
-	// Preconditions: component_idx < rank
-	constexpr const_reference operator[](size_t component_idx) const noexcept
-	{
-		fail_fast_assert(component_idx < Rank, "Component index must be less than rank");
-		return elems[component_idx];
-	}
+    // Preconditions: component_idx < rank
+    constexpr const_reference operator[](size_t component_idx) const noexcept
+    {
+        fail_fast_assert(component_idx < Rank, "Component index must be less than rank");
+        return elems[component_idx];
+    }
 
-	constexpr bool operator==(const index& rhs) const noexcept
-	{
-		return std::equal(elems, elems + rank, rhs.elems);
-	}
+    constexpr bool operator==(const index& rhs) const noexcept
+    {
+        return std::equal(elems, elems + rank, rhs.elems);
+    }
 
-	constexpr bool operator!=(const index& rhs) const noexcept
-	{
-		return !(this == rhs);
-	}
+    constexpr bool operator!=(const index& rhs) const noexcept
+    {
+        return !(this == rhs);
+    }
 
-	constexpr index operator+() const noexcept
-	{
-		return *this;
-	}
+    constexpr index operator+() const noexcept
+    {
+        return *this;
+    }
 
-	constexpr index operator-() const noexcept
-	{
-		index ret = *this;
-		std::transform(ret, ret + rank, ret, std::negate<value_type>{});
-		return ret;
-	}
+    constexpr index operator-() const noexcept
+    {
+        index ret = *this;
+        std::transform(ret, ret + rank, ret, std::negate<value_type>{});
+        return ret;
+    }
 
-	constexpr index operator+(const index& rhs) const noexcept
-	{
-		index ret = *this;
-		ret += rhs;
-		return ret;
-	}
+    constexpr index operator+(const index& rhs) const noexcept
+    {
+        index ret = *this;
+        ret += rhs;
+        return ret;
+    }
 
-	constexpr index operator-(const index& rhs) const noexcept
-	{
-		index ret = *this;
-		ret -= rhs;
-		return ret;
-	}
+    constexpr index operator-(const index& rhs) const noexcept
+    {
+        index ret = *this;
+        ret -= rhs;
+        return ret;
+    }
 
-	constexpr index& operator+=(const index& rhs) noexcept
-	{
-		std::transform(elems, elems + rank, rhs.elems, elems, std::plus<value_type>{});
-		return *this;
-	}
+    constexpr index& operator+=(const index& rhs) noexcept
+    {
+        std::transform(elems, elems + rank, rhs.elems, elems, std::plus<value_type>{});
+        return *this;
+    }
 
-	constexpr index& operator-=(const index& rhs) noexcept
-	{
-		std::transform(elems, elems + rank, rhs.elems, elems, std::minus<value_type>{});
-		return *this;
-	}
+    constexpr index& operator-=(const index& rhs) noexcept
+    {
+        std::transform(elems, elems + rank, rhs.elems, elems, std::minus<value_type>{});
+        return *this;
+    }
 
-	constexpr index operator*(value_type v) const noexcept
-	{
-		index ret = *this;
-		ret *= v;
-		return ret;
-	}
+    constexpr index operator*(value_type v) const noexcept
+    {
+        index ret = *this;
+        ret *= v;
+        return ret;
+    }
 
-	constexpr index operator/(value_type v) const noexcept
-	{
-		index ret = *this;
-		ret /= v;
-		return ret;
-	}
+    constexpr index operator/(value_type v) const noexcept
+    {
+        index ret = *this;
+        ret /= v;
+        return ret;
+    }
 
-	friend constexpr index operator*(value_type v, const index& rhs) noexcept
-	{
-		return rhs * v;
-	}
+    friend constexpr index operator*(value_type v, const index& rhs) noexcept
+    {
+        return rhs * v;
+    }
 
-	constexpr index& operator*=(value_type v) noexcept
-	{
-		std::transform(elems, elems + rank, elems, [v](value_type x) { return std::multiplies<value_type>{}(x, v); });
-		return *this;
-	}
+    constexpr index& operator*=(value_type v) noexcept
+    {
+        std::transform(elems, elems + rank, elems, [v](value_type x) { return std::multiplies<value_type>{}(x, v); });
+        return *this;
+    }
 
-	constexpr index& operator/=(value_type v) noexcept
-	{
-		std::transform(elems, elems + rank, elems, [v](value_type x) { return std::divides<value_type>{}(x, v); });
-		return *this;
-	}
+    constexpr index& operator/=(value_type v) noexcept
+    {
+        std::transform(elems, elems + rank, elems, [v](value_type x) { return std::divides<value_type>{}(x, v); });
+        return *this;
+    }
 
 private:
-	value_type elems[Rank] = {};
+    value_type elems[Rank] = {};
 };
 
 #ifndef _MSC_VER
 
 struct static_bounds_dynamic_range_t
 {
-	template <typename T, typename Dummy = std::enable_if_t<std::is_integral<T>::value>>
-	constexpr operator T() const noexcept
-	{
-		return static_cast<T>(-1);
-	}
+    template <typename T, typename Dummy = std::enable_if_t<std::is_integral<T>::value>>
+    constexpr operator T() const noexcept
+    {
+        return static_cast<T>(-1);
+    }
 
-	template <typename T, typename Dummy = std::enable_if_t<std::is_integral<T>::value>>
-	constexpr bool operator ==(T other) const noexcept
-	{
-		return static_cast<T>(-1) == other;
-	}
+    template <typename T, typename Dummy = std::enable_if_t<std::is_integral<T>::value>>
+    constexpr bool operator ==(T other) const noexcept
+    {
+        return static_cast<T>(-1) == other;
+    }
 
-	template <typename T, typename Dummy = std::enable_if_t<std::is_integral<T>::value>>
-	constexpr bool operator !=(T other) const noexcept
-	{
-		return static_cast<T>(-1) != other;
-	}
+    template <typename T, typename Dummy = std::enable_if_t<std::is_integral<T>::value>>
+    constexpr bool operator !=(T other) const noexcept
+    {
+        return static_cast<T>(-1) != other;
+    }
 
 };
 
 template <typename T, typename Dummy = std::enable_if_t<std::is_integral<T>::value>>
 constexpr bool operator ==(T left, static_bounds_dynamic_range_t right) noexcept
 {
-	return right == left;
+    return right == left;
 }
 
 template <typename T, typename Dummy = std::enable_if_t<std::is_integral<T>::value>>
 constexpr bool operator !=(T left, static_bounds_dynamic_range_t right) noexcept
 {
-	return right != left;
+    return right != left;
 }
 
 constexpr static_bounds_dynamic_range_t dynamic_range{};
@@ -272,263 +272,263 @@ struct contiguous_mapping_tag : generalized_mapping_tag {};
 namespace details
 {
 
-	template <std::ptrdiff_t Left, std::ptrdiff_t Right>
-	struct LessThan
-	{
-		static const bool value = Left < Right;
-	};
+    template <std::ptrdiff_t Left, std::ptrdiff_t Right>
+    struct LessThan
+    {
+        static const bool value = Left < Right;
+    };
 
-	template <std::ptrdiff_t... Ranges>
-	struct BoundsRanges {
-        	using size_type = std::ptrdiff_t;
-		static const size_type Depth = 0;
-		static const size_type DynamicNum = 0;
-		static const size_type CurrentRange = 1;
-		static const size_type TotalSize = 1;
+    template <std::ptrdiff_t... Ranges>
+    struct BoundsRanges {
+            using size_type = std::ptrdiff_t;
+        static const size_type Depth = 0;
+        static const size_type DynamicNum = 0;
+        static const size_type CurrentRange = 1;
+        static const size_type TotalSize = 1;
 
         // TODO : following signature is for work around VS bug
         template <typename OtherRange>
-		BoundsRanges(const OtherRange&, bool /* firstLevel */)
+        BoundsRanges(const OtherRange&, bool /* firstLevel */)
         {}
-		
-		BoundsRanges (const BoundsRanges&) = default;
-		BoundsRanges(const std::ptrdiff_t* const) { }
-		BoundsRanges() = default;
+        
+        BoundsRanges (const BoundsRanges&) = default;
+        BoundsRanges(const std::ptrdiff_t* const) { }
+        BoundsRanges() = default;
 
 
-		template <typename T, size_t Dim>
-		void serialize(T&) const
+        template <typename T, size_t Dim>
+        void serialize(T&) const
         {}
 
-		template <typename T, size_t Dim>
-		size_type linearize(const T&) const
+        template <typename T, size_t Dim>
+        size_type linearize(const T&) const
         { 
-			return 0;
-		}
+            return 0;
+        }
 
-		template <typename T, size_t Dim>
-		bool contains(const T&) const
+        template <typename T, size_t Dim>
+        bool contains(const T&) const
         {
-			return 0;
-		}
+            return 0;
+        }
 
-		size_type totalSize() const noexcept
+        size_type totalSize() const noexcept
         {
-			return TotalSize;
-		}
+            return TotalSize;
+        }
 
-		bool operator==(const BoundsRanges&) const noexcept
-		{
-			return true;
-		}
-	};
-
-	template <std::ptrdiff_t... RestRanges>
-	struct BoundsRanges <dynamic_range, RestRanges...> : BoundsRanges<RestRanges...>{
-		using Base = BoundsRanges <RestRanges... >;
-        	using size_type = std::ptrdiff_t;
-		static const size_t Depth = Base::Depth + 1;
-		static const size_t DynamicNum = Base::DynamicNum + 1;
-		static const size_type CurrentRange = dynamic_range;
-		static const size_type TotalSize = dynamic_range;
-		const size_type m_bound;
-
-		BoundsRanges (const BoundsRanges&) = default;
-		
-	        BoundsRanges(const std::ptrdiff_t* const arr) : Base(arr + 1), m_bound(*arr * this->Base::totalSize())
-		{
-			fail_fast_assert(0 <= *arr);
-		}
-
-		BoundsRanges() : m_bound(0) {}
-
-		template <std::ptrdiff_t OtherRange, std::ptrdiff_t... RestOtherRanges>
-        	BoundsRanges(const BoundsRanges<OtherRange, RestOtherRanges...>& other, bool /* firstLevel */ = true) :
-            	Base(static_cast<const BoundsRanges<RestOtherRanges...>&>(other), false), m_bound(other.totalSize())
-        	{}
-
-		template <typename T, size_t Dim = 0>
-		void serialize(T& arr) const
+        bool operator==(const BoundsRanges&) const noexcept
         {
-			arr[Dim] = elementNum();
-			this->Base::template serialize<T, Dim + 1>(arr);
-		}
+            return true;
+        }
+    };
 
-		template <typename T, size_t Dim = 0>
-		size_type linearize(const T& arr) const
+    template <std::ptrdiff_t... RestRanges>
+    struct BoundsRanges <dynamic_range, RestRanges...> : BoundsRanges<RestRanges...>{
+        using Base = BoundsRanges <RestRanges... >;
+            using size_type = std::ptrdiff_t;
+        static const size_t Depth = Base::Depth + 1;
+        static const size_t DynamicNum = Base::DynamicNum + 1;
+        static const size_type CurrentRange = dynamic_range;
+        static const size_type TotalSize = dynamic_range;
+        const size_type m_bound;
+
+        BoundsRanges (const BoundsRanges&) = default;
+        
+            BoundsRanges(const std::ptrdiff_t* const arr) : Base(arr + 1), m_bound(*arr * this->Base::totalSize())
+        {
+            fail_fast_assert(0 <= *arr);
+        }
+
+        BoundsRanges() : m_bound(0) {}
+
+        template <std::ptrdiff_t OtherRange, std::ptrdiff_t... RestOtherRanges>
+            BoundsRanges(const BoundsRanges<OtherRange, RestOtherRanges...>& other, bool /* firstLevel */ = true) :
+                Base(static_cast<const BoundsRanges<RestOtherRanges...>&>(other), false), m_bound(other.totalSize())
+            {}
+
+        template <typename T, size_t Dim = 0>
+        void serialize(T& arr) const
+        {
+            arr[Dim] = elementNum();
+            this->Base::template serialize<T, Dim + 1>(arr);
+        }
+
+        template <typename T, size_t Dim = 0>
+        size_type linearize(const T& arr) const
         { 
-			const size_type index = this->Base::totalSize() * arr[Dim];
-			fail_fast_assert(index < m_bound);
-			return index + this->Base::template linearize<T, Dim + 1>(arr);
-		}
-		
-		template <typename T, size_t Dim = 0>
-		size_type contains(const T & arr) const
+            const size_type index = this->Base::totalSize() * arr[Dim];
+            fail_fast_assert(index < m_bound);
+            return index + this->Base::template linearize<T, Dim + 1>(arr);
+        }
+        
+        template <typename T, size_t Dim = 0>
+        size_type contains(const T & arr) const
         {
-			const ptrdiff_t last = this->Base::template contains<T, Dim + 1>(arr);
-			if (last == -1)
-				return -1;
-			const ptrdiff_t cur = this->Base::totalSize() * arr[Dim];
-			return cur < m_bound ? cur + last : -1;
-		}
-		
-		size_type totalSize() const noexcept
+            const ptrdiff_t last = this->Base::template contains<T, Dim + 1>(arr);
+            if (last == -1)
+                return -1;
+            const ptrdiff_t cur = this->Base::totalSize() * arr[Dim];
+            return cur < m_bound ? cur + last : -1;
+        }
+        
+        size_type totalSize() const noexcept
         {
-			return m_bound;
-		}
-		
+            return m_bound;
+        }
+        
         size_type elementNum() const noexcept
         {
-			return totalSize() / this->Base::totalSize();
-		}
-		
+            return totalSize() / this->Base::totalSize();
+        }
+        
         size_type elementNum(size_t dim) const noexcept
         {
-			if (dim > 0)
-				return this->Base::elementNum(dim - 1);
-			else
-				return elementNum();
-		}
+            if (dim > 0)
+                return this->Base::elementNum(dim - 1);
+            else
+                return elementNum();
+        }
 
-		bool operator == (const BoundsRanges & rhs) const noexcept
-		{
-			return m_bound == rhs.m_bound && static_cast<const Base&>(*this) == static_cast<const Base&>(rhs);
-		}
-	};
-
-	template <std::ptrdiff_t CurRange, std::ptrdiff_t... RestRanges>
-	struct BoundsRanges <CurRange, RestRanges...> : BoundsRanges<RestRanges...>
-    {
-		using Base = BoundsRanges <RestRanges... >;
-        	using size_type = std::ptrdiff_t;
-		static const size_t Depth = Base::Depth + 1;
-		static const size_t DynamicNum = Base::DynamicNum;
-		static const size_type CurrentRange = CurRange;
-		static const size_type TotalSize = Base::TotalSize == dynamic_range ? dynamic_range : CurrentRange * Base::TotalSize;
-
-		BoundsRanges (const BoundsRanges&) = default;
-		BoundsRanges(const std::ptrdiff_t* const arr) : Base(arr) { }
-		BoundsRanges() = default;
-
-		template <std::ptrdiff_t OtherRange, std::ptrdiff_t... RestOtherRanges>
-		BoundsRanges(const BoundsRanges<OtherRange, RestOtherRanges...>&other, bool firstLevel = true) : Base(static_cast<const BoundsRanges<RestOtherRanges...>&>(other), false)
-		{
-			fail_fast_assert((firstLevel && totalSize() <= other.totalSize()) || totalSize() == other.totalSize());
-		}
-
-		template <typename T, size_t Dim = 0>
-		void serialize(T& arr) const
+        bool operator == (const BoundsRanges & rhs) const noexcept
         {
-			arr[Dim] = elementNum();
-			this->Base::template serialize<T, Dim + 1>(arr);
-		}
+            return m_bound == rhs.m_bound && static_cast<const Base&>(*this) == static_cast<const Base&>(rhs);
+        }
+    };
 
-		template <typename T, size_t Dim = 0>
-		size_type linearize(const T& arr) const
+    template <std::ptrdiff_t CurRange, std::ptrdiff_t... RestRanges>
+    struct BoundsRanges <CurRange, RestRanges...> : BoundsRanges<RestRanges...>
+    {
+        using Base = BoundsRanges <RestRanges... >;
+            using size_type = std::ptrdiff_t;
+        static const size_t Depth = Base::Depth + 1;
+        static const size_t DynamicNum = Base::DynamicNum;
+        static const size_type CurrentRange = CurRange;
+        static const size_type TotalSize = Base::TotalSize == dynamic_range ? dynamic_range : CurrentRange * Base::TotalSize;
+
+        BoundsRanges (const BoundsRanges&) = default;
+        BoundsRanges(const std::ptrdiff_t* const arr) : Base(arr) { }
+        BoundsRanges() = default;
+
+        template <std::ptrdiff_t OtherRange, std::ptrdiff_t... RestOtherRanges>
+        BoundsRanges(const BoundsRanges<OtherRange, RestOtherRanges...>&other, bool firstLevel = true) : Base(static_cast<const BoundsRanges<RestOtherRanges...>&>(other), false)
+        {
+            fail_fast_assert((firstLevel && totalSize() <= other.totalSize()) || totalSize() == other.totalSize());
+        }
+
+        template <typename T, size_t Dim = 0>
+        void serialize(T& arr) const
+        {
+            arr[Dim] = elementNum();
+            this->Base::template serialize<T, Dim + 1>(arr);
+        }
+
+        template <typename T, size_t Dim = 0>
+        size_type linearize(const T& arr) const
         {  
-			fail_fast_assert(arr[Dim] < CurrentRange, "Index is out of range");
-			return this->Base::totalSize() * arr[Dim] + this->Base::template linearize<T, Dim + 1>(arr);
-		}
+            fail_fast_assert(arr[Dim] < CurrentRange, "Index is out of range");
+            return this->Base::totalSize() * arr[Dim] + this->Base::template linearize<T, Dim + 1>(arr);
+        }
 
-		template <typename T, size_t Dim = 0>
+        template <typename T, size_t Dim = 0>
         size_type contains(const T& arr) const
         {
-			if (arr[Dim] >= CurrentRange)
-				return -1;
-			const size_type last = this->Base::template contains<T, Dim + 1>(arr);
-			if (last == -1)
-				return -1;
-			return this->Base::totalSize() * arr[Dim] + last;
-		}
+            if (arr[Dim] >= CurrentRange)
+                return -1;
+            const size_type last = this->Base::template contains<T, Dim + 1>(arr);
+            if (last == -1)
+                return -1;
+            return this->Base::totalSize() * arr[Dim] + last;
+        }
 
-		size_type totalSize() const noexcept
+        size_type totalSize() const noexcept
         {
-			return CurrentRange * this->Base::totalSize();
-		}
+            return CurrentRange * this->Base::totalSize();
+        }
 
         size_type elementNum() const noexcept
         {
-			return CurrentRange;
-		}
+            return CurrentRange;
+        }
 
-		size_type elementNum(size_t dim) const noexcept
+        size_type elementNum(size_t dim) const noexcept
         {
-			if (dim > 0)
-				return this->Base::elementNum(dim - 1);
-			else
-				return elementNum();
-		}
+            if (dim > 0)
+                return this->Base::elementNum(dim - 1);
+            else
+                return elementNum();
+        }
 
-		bool operator== (const BoundsRanges& rhs) const noexcept
-		{
-			return static_cast<const Base &>(*this) == static_cast<const Base &>(rhs);
-		}
-	};
+        bool operator== (const BoundsRanges& rhs) const noexcept
+        {
+            return static_cast<const Base &>(*this) == static_cast<const Base &>(rhs);
+        }
+    };
 
-	template <typename SourceType, typename TargetType, size_t Rank>
-	struct BoundsRangeConvertible2;
+    template <typename SourceType, typename TargetType, size_t Rank>
+    struct BoundsRangeConvertible2;
 
-	template <size_t Rank, typename SourceType, typename TargetType, typename Ret = BoundsRangeConvertible2<typename SourceType::Base, typename TargetType::Base, Rank>>
-	auto helpBoundsRangeConvertible(SourceType, TargetType, std::true_type) -> Ret;
+    template <size_t Rank, typename SourceType, typename TargetType, typename Ret = BoundsRangeConvertible2<typename SourceType::Base, typename TargetType::Base, Rank>>
+    auto helpBoundsRangeConvertible(SourceType, TargetType, std::true_type) -> Ret;
 
-	template <size_t Rank, typename SourceType, typename TargetType>
-	auto helpBoundsRangeConvertible(SourceType, TargetType, ...) -> std::false_type;
-	
-	template <typename SourceType, typename TargetType, size_t Rank>
-	struct BoundsRangeConvertible2 : decltype(helpBoundsRangeConvertible<Rank - 1>(SourceType(), TargetType(), 
-		std::integral_constant<bool, SourceType::Depth == TargetType::Depth 
-		&& (SourceType::CurrentRange == TargetType::CurrentRange || TargetType::CurrentRange == dynamic_range || SourceType::CurrentRange == dynamic_range)>())) 
-	{};
+    template <size_t Rank, typename SourceType, typename TargetType>
+    auto helpBoundsRangeConvertible(SourceType, TargetType, ...) -> std::false_type;
+    
+    template <typename SourceType, typename TargetType, size_t Rank>
+    struct BoundsRangeConvertible2 : decltype(helpBoundsRangeConvertible<Rank - 1>(SourceType(), TargetType(), 
+        std::integral_constant<bool, SourceType::Depth == TargetType::Depth 
+        && (SourceType::CurrentRange == TargetType::CurrentRange || TargetType::CurrentRange == dynamic_range || SourceType::CurrentRange == dynamic_range)>())) 
+    {};
 
-	template <typename SourceType, typename TargetType>
-	struct BoundsRangeConvertible2<SourceType, TargetType, 0> : std::true_type {};
+    template <typename SourceType, typename TargetType>
+    struct BoundsRangeConvertible2<SourceType, TargetType, 0> : std::true_type {};
 
-	template <typename SourceType, typename TargetType, std::ptrdiff_t Rank = TargetType::Depth>
-	struct BoundsRangeConvertible : decltype(helpBoundsRangeConvertible<Rank - 1>(SourceType(), TargetType(), 
-		std::integral_constant<bool, SourceType::Depth == TargetType::Depth 
-		&& (!LessThan<SourceType::CurrentRange, TargetType::CurrentRange>::value || TargetType::CurrentRange == dynamic_range || SourceType::CurrentRange == dynamic_range)>())) 
-	{};
-	template <typename SourceType, typename TargetType>
-	struct BoundsRangeConvertible<SourceType, TargetType, 0> : std::true_type {};
+    template <typename SourceType, typename TargetType, std::ptrdiff_t Rank = TargetType::Depth>
+    struct BoundsRangeConvertible : decltype(helpBoundsRangeConvertible<Rank - 1>(SourceType(), TargetType(), 
+        std::integral_constant<bool, SourceType::Depth == TargetType::Depth 
+        && (!LessThan<SourceType::CurrentRange, TargetType::CurrentRange>::value || TargetType::CurrentRange == dynamic_range || SourceType::CurrentRange == dynamic_range)>())) 
+    {};
+    template <typename SourceType, typename TargetType>
+    struct BoundsRangeConvertible<SourceType, TargetType, 0> : std::true_type {};
 
-	template <typename TypeChain>
-	struct TypeListIndexer
-	{
-		const TypeChain & obj;
-		TypeListIndexer(const TypeChain & obj) :obj(obj){}
-		template<size_t N>
-		const TypeChain & getObj(std::true_type)
-		{
-			return obj;
-		}
-		template<size_t N, typename MyChain = TypeChain, typename MyBase = typename MyChain::Base>
-		auto getObj(std::false_type) -> decltype(TypeListIndexer<MyBase>(static_cast<const MyBase &>(obj)).template get<N>())
-		{
-			return TypeListIndexer<MyBase>(static_cast<const MyBase &>(obj)).template get<N>();
-		}
-		template <size_t N>
-		auto get() -> decltype(getObj<N - 1>(std::integral_constant<bool, true>()))
-		{
-			return getObj<N - 1>(std::integral_constant<bool, N == 0>());
-		}
-	};
+    template <typename TypeChain>
+    struct TypeListIndexer
+    {
+        const TypeChain & obj;
+        TypeListIndexer(const TypeChain & obj) :obj(obj){}
+        template<size_t N>
+        const TypeChain & getObj(std::true_type)
+        {
+            return obj;
+        }
+        template<size_t N, typename MyChain = TypeChain, typename MyBase = typename MyChain::Base>
+        auto getObj(std::false_type) -> decltype(TypeListIndexer<MyBase>(static_cast<const MyBase &>(obj)).template get<N>())
+        {
+            return TypeListIndexer<MyBase>(static_cast<const MyBase &>(obj)).template get<N>();
+        }
+        template <size_t N>
+        auto get() -> decltype(getObj<N - 1>(std::integral_constant<bool, true>()))
+        {
+            return getObj<N - 1>(std::integral_constant<bool, N == 0>());
+        }
+    };
 
-	template <typename TypeChain>
-	TypeListIndexer<TypeChain> createTypeListIndexer(const TypeChain &obj)
-	{
-		return TypeListIndexer<TypeChain>(obj);
-	}
+    template <typename TypeChain>
+    TypeListIndexer<TypeChain> createTypeListIndexer(const TypeChain &obj)
+    {
+        return TypeListIndexer<TypeChain>(obj);
+    }
 
-	template <size_t Rank, bool Enabled = (Rank > 1), typename Ret = std::enable_if_t<Enabled, index<Rank - 1>>>
-	constexpr Ret shift_left(const index<Rank>& other) noexcept
-	{
-		Ret ret{};
-		for (size_t i = 0; i < Rank - 1; ++i)
-		{
-			ret[i] = other[i + 1];
-		}
-		return ret;
-	}
+    template <size_t Rank, bool Enabled = (Rank > 1), typename Ret = std::enable_if_t<Enabled, index<Rank - 1>>>
+    constexpr Ret shift_left(const index<Rank>& other) noexcept
+    {
+        Ret ret{};
+        for (size_t i = 0; i < Rank - 1; ++i)
+        {
+            ret[i] = other[i + 1];
+        }
+        return ret;
+    }
 }
 
 template <typename IndexType>
@@ -538,242 +538,242 @@ template <std::ptrdiff_t... Ranges>
 class static_bounds
 {
 public:
-	static_bounds(const details::BoundsRanges<Ranges...>&) {
-	}
+    static_bounds(const details::BoundsRanges<Ranges...>&) {
+    }
 };
 
 template <std::ptrdiff_t FirstRange, std::ptrdiff_t... RestRanges>
 class static_bounds<FirstRange, RestRanges...>
 {
-	using MyRanges = details::BoundsRanges<FirstRange, RestRanges... >;
+    using MyRanges = details::BoundsRanges<FirstRange, RestRanges... >;
 
-	MyRanges m_ranges;
-	constexpr static_bounds(const MyRanges& range) : m_ranges(range)
+    MyRanges m_ranges;
+    constexpr static_bounds(const MyRanges& range) : m_ranges(range)
     {}
-	
-	template <std::ptrdiff_t... OtherRanges>
-	friend class static_bounds;
+    
+    template <std::ptrdiff_t... OtherRanges>
+    friend class static_bounds;
 
 public:
-	static const size_t rank = MyRanges::Depth;
-	static const size_t dynamic_rank = MyRanges::DynamicNum;
-	static const std::ptrdiff_t static_size = MyRanges::TotalSize;
+    static const size_t rank = MyRanges::Depth;
+    static const size_t dynamic_rank = MyRanges::DynamicNum;
+    static const std::ptrdiff_t static_size = MyRanges::TotalSize;
 
-	using size_type = std::ptrdiff_t;
-	using index_type = index<rank>;
+    using size_type = std::ptrdiff_t;
+    using index_type = index<rank>;
     using const_index_type = std::add_const_t<index_type>;
     using iterator = bounds_iterator<const_index_type>;
     using const_iterator = bounds_iterator<const_index_type>;
     using difference_type = std::ptrdiff_t;
-	using sliced_type = static_bounds<RestRanges...>;
-	using mapping_type = contiguous_mapping_tag;
+    using sliced_type = static_bounds<RestRanges...>;
+    using mapping_type = contiguous_mapping_tag;
 
-	constexpr static_bounds(const static_bounds&) = default;
-	
-	template <std::ptrdiff_t... Ranges, typename Dummy = std::enable_if_t<
-		details::BoundsRangeConvertible<details::BoundsRanges<Ranges...>, details::BoundsRanges <FirstRange, RestRanges... >>::value>>
+    constexpr static_bounds(const static_bounds&) = default;
+    
+    template <std::ptrdiff_t... Ranges, typename Dummy = std::enable_if_t<
+        details::BoundsRangeConvertible<details::BoundsRanges<Ranges...>, details::BoundsRanges <FirstRange, RestRanges... >>::value>>
     constexpr static_bounds(const static_bounds<Ranges...>& other) : m_ranges(other.m_ranges)
     {}
                                                        
-	constexpr static_bounds(std::initializer_list<size_type> il) : m_ranges((const std::ptrdiff_t*)il.begin())
-	{
-		fail_fast_assert((MyRanges::DynamicNum == 0 && il.size() == 1 && *il.begin() == static_size) || MyRanges::DynamicNum == il.size(), "Size of the initializer list must match the rank of the array");
-		fail_fast_assert(m_ranges.totalSize() <= PTRDIFF_MAX, "Size of the range is larger than the max element of the size type");
-	}
-	
-	constexpr static_bounds() = default;
+    constexpr static_bounds(std::initializer_list<size_type> il) : m_ranges((const std::ptrdiff_t*)il.begin())
+    {
+        fail_fast_assert((MyRanges::DynamicNum == 0 && il.size() == 1 && *il.begin() == static_size) || MyRanges::DynamicNum == il.size(), "Size of the initializer list must match the rank of the array");
+        fail_fast_assert(m_ranges.totalSize() <= PTRDIFF_MAX, "Size of the range is larger than the max element of the size type");
+    }
+    
+    constexpr static_bounds() = default;
 
-	constexpr static_bounds& operator=(const static_bounds& otherBounds)
-	{
-		new(&m_ranges) MyRanges (otherBounds.m_ranges);
-		return *this;
-	}
+    constexpr static_bounds& operator=(const static_bounds& otherBounds)
+    {
+        new(&m_ranges) MyRanges (otherBounds.m_ranges);
+        return *this;
+    }
 
-	constexpr sliced_type slice() const noexcept
-	{
-		return sliced_type{static_cast<const details::BoundsRanges<RestRanges...> &>(m_ranges)};
-	}
+    constexpr sliced_type slice() const noexcept
+    {
+        return sliced_type{static_cast<const details::BoundsRanges<RestRanges...> &>(m_ranges)};
+    }
 
-	constexpr size_type stride() const noexcept
-	{
-		return rank > 1 ? slice().size() : 1;
-	}
-	
-	constexpr size_type size() const noexcept
-	{
-		return m_ranges.totalSize();
-	}
+    constexpr size_type stride() const noexcept
+    {
+        return rank > 1 ? slice().size() : 1;
+    }
+    
+    constexpr size_type size() const noexcept
+    {
+        return m_ranges.totalSize();
+    }
 
-	constexpr size_type total_size() const noexcept
-	{
-		return m_ranges.totalSize();
-	}
-	
-	constexpr size_type linearize(const index_type & idx) const
-	{
-		return m_ranges.linearize(idx);
-	}
-	
-	constexpr bool contains(const index_type& idx) const noexcept
-	{
-		return m_ranges.contains(idx) != -1;
-	}
-	
-	constexpr size_type operator[](size_t index) const noexcept
-	{
-		return m_ranges.elementNum(index);
-	}
-	
-	template <size_t Dim = 0>
-	constexpr size_type extent() const noexcept
-	{
-		static_assert(Dim < rank, "dimension should be less than rank (dimension count starts from 0)");
-		return details::createTypeListIndexer(m_ranges).template get<Dim>().elementNum();
-	}
-	
-	constexpr index_type index_bounds() const noexcept
-	{
-		size_type extents[rank] = {};
-		m_ranges.serialize(extents);
-		return{ extents };
-	}
-	
-	template <std::ptrdiff_t... Ranges>
-	constexpr bool operator == (const static_bounds<Ranges...>& rhs) const noexcept
-	{
-		return this->size() == rhs.size();
-	}
-	
-	template <std::ptrdiff_t... Ranges>
-	constexpr bool operator != (const static_bounds<Ranges...>& rhs) const noexcept
-	{
-		return !(*this == rhs);
-	}
-	
-	constexpr const_iterator begin() const noexcept
-	{
-		return const_iterator(*this, index_type{});
-	}
-	
-	constexpr const_iterator end() const noexcept
-	{
-		return const_iterator(*this, this->index_bounds());
-	}
+    constexpr size_type total_size() const noexcept
+    {
+        return m_ranges.totalSize();
+    }
+    
+    constexpr size_type linearize(const index_type & idx) const
+    {
+        return m_ranges.linearize(idx);
+    }
+    
+    constexpr bool contains(const index_type& idx) const noexcept
+    {
+        return m_ranges.contains(idx) != -1;
+    }
+    
+    constexpr size_type operator[](size_t index) const noexcept
+    {
+        return m_ranges.elementNum(index);
+    }
+    
+    template <size_t Dim = 0>
+    constexpr size_type extent() const noexcept
+    {
+        static_assert(Dim < rank, "dimension should be less than rank (dimension count starts from 0)");
+        return details::createTypeListIndexer(m_ranges).template get<Dim>().elementNum();
+    }
+    
+    constexpr index_type index_bounds() const noexcept
+    {
+        size_type extents[rank] = {};
+        m_ranges.serialize(extents);
+        return{ extents };
+    }
+    
+    template <std::ptrdiff_t... Ranges>
+    constexpr bool operator == (const static_bounds<Ranges...>& rhs) const noexcept
+    {
+        return this->size() == rhs.size();
+    }
+    
+    template <std::ptrdiff_t... Ranges>
+    constexpr bool operator != (const static_bounds<Ranges...>& rhs) const noexcept
+    {
+        return !(*this == rhs);
+    }
+    
+    constexpr const_iterator begin() const noexcept
+    {
+        return const_iterator(*this, index_type{});
+    }
+    
+    constexpr const_iterator end() const noexcept
+    {
+        return const_iterator(*this, this->index_bounds());
+    }
 };
 
 template <size_t Rank>
 class strided_bounds 
 {
-	template <size_t OtherRank>
-	friend class strided_bounds;
+    template <size_t OtherRank>
+    friend class strided_bounds;
 
 public:
-	static const size_t rank = Rank;
+    static const size_t rank = Rank;
     using value_type      = std::ptrdiff_t;
-	using reference       = std::add_lvalue_reference_t<value_type>;
-	using const_reference = std::add_const_t<reference>;
-	using size_type       = value_type;
-	using difference_type = value_type;
-	using index_type      = index<rank>;
+    using reference       = std::add_lvalue_reference_t<value_type>;
+    using const_reference = std::add_const_t<reference>;
+    using size_type       = value_type;
+    using difference_type = value_type;
+    using index_type      = index<rank>;
     using const_index_type = std::add_const_t<index_type>;
     using iterator = bounds_iterator<const_index_type>;
     using const_iterator = bounds_iterator<const_index_type>;
     static const value_type dynamic_rank = rank;
-	static const value_type static_size = dynamic_range;
-	using sliced_type = std::conditional_t<rank != 0, strided_bounds<rank - 1>, void>;
-	using mapping_type = generalized_mapping_tag;
+    static const value_type static_size = dynamic_range;
+    using sliced_type = std::conditional_t<rank != 0, strided_bounds<rank - 1>, void>;
+    using mapping_type = generalized_mapping_tag;
 
-	constexpr strided_bounds(const strided_bounds &) noexcept = default;
+    constexpr strided_bounds(const strided_bounds &) noexcept = default;
 
     constexpr strided_bounds(const value_type(&values)[rank], index_type strides)
         : m_extents(values), m_strides(std::move(strides))
     {}
 
-	constexpr strided_bounds(const index_type &extents, const index_type &strides) noexcept
-		: m_extents(extents), m_strides(strides)
-	{}
+    constexpr strided_bounds(const index_type &extents, const index_type &strides) noexcept
+        : m_extents(extents), m_strides(strides)
+    {}
 
-	constexpr index_type strides() const noexcept
-	{
-		return m_strides;
-	}
+    constexpr index_type strides() const noexcept
+    {
+        return m_strides;
+    }
 
-	constexpr size_type total_size() const noexcept
-	{
-		size_type ret = 0;
-		for (size_t i = 0; i < rank; ++i)
-		{
-			ret += (m_extents[i] - 1) * m_strides[i];
-		}
-		return ret + 1;
-	}
-	
+    constexpr size_type total_size() const noexcept
+    {
+        size_type ret = 0;
+        for (size_t i = 0; i < rank; ++i)
+        {
+            ret += (m_extents[i] - 1) * m_strides[i];
+        }
+        return ret + 1;
+    }
+    
     constexpr size_type size() const noexcept
-	{
-		size_type ret = 1;
-		for (size_t i = 0; i < rank; ++i)
-		{
-			ret *= m_extents[i];
-		}
-		return ret;
-	}
-	
+    {
+        size_type ret = 1;
+        for (size_t i = 0; i < rank; ++i)
+        {
+            ret *= m_extents[i];
+        }
+        return ret;
+    }
+    
     constexpr bool contains(const index_type& idx) const noexcept
-	{
-		for (size_t i = 0; i < rank; ++i)
-		{
-			if (idx[i] < 0 || idx[i] >= m_extents[i])
-				return false;
-		}
-		return true;
-	}
+    {
+        for (size_t i = 0; i < rank; ++i)
+        {
+            if (idx[i] < 0 || idx[i] >= m_extents[i])
+                return false;
+        }
+        return true;
+    }
 
-	constexpr size_type linearize(const index_type& idx) const noexcept
-	{
-		size_type ret = 0;
-		for (size_t i = 0; i < rank; i++)
-		{
-			fail_fast_assert(idx[i] < m_extents[i], "index is out of bounds of the array");
-			ret += idx[i] * m_strides[i];
-		}
-		return ret;
-	}
-	
+    constexpr size_type linearize(const index_type& idx) const noexcept
+    {
+        size_type ret = 0;
+        for (size_t i = 0; i < rank; i++)
+        {
+            fail_fast_assert(idx[i] < m_extents[i], "index is out of bounds of the array");
+            ret += idx[i] * m_strides[i];
+        }
+        return ret;
+    }
+    
     constexpr size_type stride() const noexcept
-	{
-		return m_strides[0];
-	}
-	
+    {
+        return m_strides[0];
+    }
+    
     template <bool Enabled = (rank > 1), typename Ret = std::enable_if_t<Enabled, sliced_type>>
-	constexpr sliced_type slice() const
-	{
-		return{ details::shift_left(m_extents), details::shift_left(m_strides) };
-	}
-	
+    constexpr sliced_type slice() const
+    {
+        return{ details::shift_left(m_extents), details::shift_left(m_strides) };
+    }
+    
     template <size_t Dim = 0>
-	constexpr size_type extent() const noexcept
-	{
-		static_assert(Dim < Rank, "dimension should be less than rank (dimension count starts from 0)");
-		return m_extents[Dim];
-	}
-	
+    constexpr size_type extent() const noexcept
+    {
+        static_assert(Dim < Rank, "dimension should be less than rank (dimension count starts from 0)");
+        return m_extents[Dim];
+    }
+    
     constexpr index_type index_bounds() const noexcept
-	{
-		return m_extents;
-	}
-	constexpr const_iterator begin() const noexcept
-	{
-		return const_iterator{ *this, index_type{} };
-	}
-	
-	constexpr const_iterator end() const noexcept
-	{
-		return const_iterator{ *this, index_bounds() };
-	}
+    {
+        return m_extents;
+    }
+    constexpr const_iterator begin() const noexcept
+    {
+        return const_iterator{ *this, index_type{} };
+    }
+    
+    constexpr const_iterator end() const noexcept
+    {
+        return const_iterator{ *this, index_bounds() };
+    }
 
 private:
-	index_type m_extents;
-	index_type m_strides;
+    index_type m_extents;
+    index_type m_strides;
 };
 
 template <typename T>
@@ -787,214 +787,214 @@ template <typename IndexType>
 class bounds_iterator: public std::iterator<std::random_access_iterator_tag, IndexType>
 {
 private:
-	using Base = std::iterator <std::random_access_iterator_tag, IndexType>;
+    using Base = std::iterator <std::random_access_iterator_tag, IndexType>;
 
 public:
-	static const size_t rank = IndexType::rank;
-	using typename Base::reference;
-	using typename Base::pointer;
-	using typename Base::difference_type;
-	using typename Base::value_type;
-	using index_type = value_type;
-	using index_size_type = typename IndexType::value_type;
-	template <typename Bounds>
-	explicit bounds_iterator(const Bounds& bnd, value_type curr) noexcept
-		: boundary(bnd.index_bounds()), curr(std::move(curr))
-	{
-		static_assert(is_bounds<Bounds>::value, "Bounds type must be provided");
-	}
+    static const size_t rank = IndexType::rank;
+    using typename Base::reference;
+    using typename Base::pointer;
+    using typename Base::difference_type;
+    using typename Base::value_type;
+    using index_type = value_type;
+    using index_size_type = typename IndexType::value_type;
+    template <typename Bounds>
+    explicit bounds_iterator(const Bounds& bnd, value_type curr) noexcept
+        : boundary(bnd.index_bounds()), curr(std::move(curr))
+    {
+        static_assert(is_bounds<Bounds>::value, "Bounds type must be provided");
+    }
 
-	constexpr reference operator*() const noexcept
-	{
-		return curr;
-	}
+    constexpr reference operator*() const noexcept
+    {
+        return curr;
+    }
 
-	constexpr pointer operator->() const noexcept
-	{
-		return &curr;
-	}
+    constexpr pointer operator->() const noexcept
+    {
+        return &curr;
+    }
 
-	constexpr bounds_iterator& operator++() noexcept
-	{
-		for (size_t i = rank; i-- > 0;)
-		{
-			if (curr[i] < boundary[i] - 1)
-			{
-				curr[i]++;
-				return *this;
-			}
-			curr[i] = 0;
-		}
-		// If we're here we've wrapped over - set to past-the-end.
-		curr = boundary;
-		return *this;
-	}
+    constexpr bounds_iterator& operator++() noexcept
+    {
+        for (size_t i = rank; i-- > 0;)
+        {
+            if (curr[i] < boundary[i] - 1)
+            {
+                curr[i]++;
+                return *this;
+            }
+            curr[i] = 0;
+        }
+        // If we're here we've wrapped over - set to past-the-end.
+        curr = boundary;
+        return *this;
+    }
 
-	constexpr bounds_iterator operator++(int) noexcept
-	{
-		auto ret = *this;
-		++(*this);
-		return ret;
-	}
+    constexpr bounds_iterator operator++(int) noexcept
+    {
+        auto ret = *this;
+        ++(*this);
+        return ret;
+    }
 
-	constexpr bounds_iterator& operator--() noexcept
-	{
-		if (!less(curr, boundary))
-		{
-			// if at the past-the-end, set to last element
-			for (size_t i = 0; i < rank; ++i)
-			{
-				curr[i] = boundary[i] - 1;
-			}
-			return *this;
-		}
-		for (size_t i = rank; i-- > 0;)
-		{
-			if (curr[i] >= 1)
-			{
-				curr[i]--;
-				return *this;
-			}
-			curr[i] = boundary[i] - 1;
-		}
-		// If we're here the preconditions were violated
-		// "pre: there exists s such that r == ++s"
-		fail_fast_assert(false);
-		return *this;
-	}
+    constexpr bounds_iterator& operator--() noexcept
+    {
+        if (!less(curr, boundary))
+        {
+            // if at the past-the-end, set to last element
+            for (size_t i = 0; i < rank; ++i)
+            {
+                curr[i] = boundary[i] - 1;
+            }
+            return *this;
+        }
+        for (size_t i = rank; i-- > 0;)
+        {
+            if (curr[i] >= 1)
+            {
+                curr[i]--;
+                return *this;
+            }
+            curr[i] = boundary[i] - 1;
+        }
+        // If we're here the preconditions were violated
+        // "pre: there exists s such that r == ++s"
+        fail_fast_assert(false);
+        return *this;
+    }
 
-	constexpr bounds_iterator operator--(int) noexcept
-	{
-		auto ret = *this;
-		--(*this);
-		return ret;
-	}
+    constexpr bounds_iterator operator--(int) noexcept
+    {
+        auto ret = *this;
+        --(*this);
+        return ret;
+    }
 
-	constexpr bounds_iterator operator+(difference_type n) const noexcept
-	{
-		bounds_iterator ret{ *this };
-		return ret += n;
-	}
+    constexpr bounds_iterator operator+(difference_type n) const noexcept
+    {
+        bounds_iterator ret{ *this };
+        return ret += n;
+    }
 
-	constexpr bounds_iterator& operator+=(difference_type n) noexcept
-	{
-		auto linear_idx = linearize(curr) + n;
-		std::remove_const_t<value_type> stride = 0;
-		stride[rank - 1] = 1;
-		for (size_t i = rank - 1; i-- > 0;)
-		{
-			stride[i] = stride[i + 1] * boundary[i + 1];
-		}
-		for (size_t i = 0; i < rank; ++i)
-		{
-			curr[i] = linear_idx / stride[i];
-			linear_idx = linear_idx % stride[i];
-		}
-		fail_fast_assert(!less(curr, index_type{}) && !less(boundary, curr), "index is out of bounds of the array");
-		return *this;
-	}
+    constexpr bounds_iterator& operator+=(difference_type n) noexcept
+    {
+        auto linear_idx = linearize(curr) + n;
+        std::remove_const_t<value_type> stride = 0;
+        stride[rank - 1] = 1;
+        for (size_t i = rank - 1; i-- > 0;)
+        {
+            stride[i] = stride[i + 1] * boundary[i + 1];
+        }
+        for (size_t i = 0; i < rank; ++i)
+        {
+            curr[i] = linear_idx / stride[i];
+            linear_idx = linear_idx % stride[i];
+        }
+        fail_fast_assert(!less(curr, index_type{}) && !less(boundary, curr), "index is out of bounds of the array");
+        return *this;
+    }
 
-	constexpr bounds_iterator operator-(difference_type n) const noexcept
-	{
-		bounds_iterator ret{ *this };
-		return ret -= n;
-	}
+    constexpr bounds_iterator operator-(difference_type n) const noexcept
+    {
+        bounds_iterator ret{ *this };
+        return ret -= n;
+    }
 
-	constexpr bounds_iterator& operator-=(difference_type n) noexcept
-	{
-		return *this += -n;
-	}
+    constexpr bounds_iterator& operator-=(difference_type n) noexcept
+    {
+        return *this += -n;
+    }
 
-	constexpr difference_type operator-(const bounds_iterator& rhs) const noexcept
-	{
-		return linearize(curr) - linearize(rhs.curr);
-	}
+    constexpr difference_type operator-(const bounds_iterator& rhs) const noexcept
+    {
+        return linearize(curr) - linearize(rhs.curr);
+    }
 
-	constexpr value_type operator[](difference_type n) const noexcept
-	{
-		return *(*this + n);
-	}
+    constexpr value_type operator[](difference_type n) const noexcept
+    {
+        return *(*this + n);
+    }
 
-	constexpr bool operator==(const bounds_iterator& rhs) const noexcept
-	{
-		return curr == rhs.curr;
-	}
+    constexpr bool operator==(const bounds_iterator& rhs) const noexcept
+    {
+        return curr == rhs.curr;
+    }
 
-	constexpr bool operator!=(const bounds_iterator& rhs) const noexcept
-	{
-		return !(*this == rhs);
-	}
+    constexpr bool operator!=(const bounds_iterator& rhs) const noexcept
+    {
+        return !(*this == rhs);
+    }
 
-	constexpr bool operator<(const bounds_iterator& rhs) const noexcept
-	{
-		return less(curr, rhs.curr);
-	}
+    constexpr bool operator<(const bounds_iterator& rhs) const noexcept
+    {
+        return less(curr, rhs.curr);
+    }
 
-	constexpr bool operator<=(const bounds_iterator& rhs) const noexcept
-	{
-		return !(rhs < *this);
-	}
+    constexpr bool operator<=(const bounds_iterator& rhs) const noexcept
+    {
+        return !(rhs < *this);
+    }
 
-	constexpr bool operator>(const bounds_iterator& rhs) const noexcept
-	{
-		return rhs < *this;
-	}
+    constexpr bool operator>(const bounds_iterator& rhs) const noexcept
+    {
+        return rhs < *this;
+    }
 
-	constexpr bool operator>=(const bounds_iterator& rhs) const noexcept
-	{
-		return !(rhs > *this);
-	}
+    constexpr bool operator>=(const bounds_iterator& rhs) const noexcept
+    {
+        return !(rhs > *this);
+    }
 
-	void swap(bounds_iterator& rhs) noexcept
-	{
-		std::swap(boundary, rhs.boundary);
-		std::swap(curr, rhs.curr);
-	}
+    void swap(bounds_iterator& rhs) noexcept
+    {
+        std::swap(boundary, rhs.boundary);
+        std::swap(curr, rhs.curr);
+    }
 private:
-	constexpr bool less(index_type& one, index_type& other) const noexcept
-	{
-		for (size_t i = 0; i < rank; ++i)
-		{
-			if (one[i] < other[i])
-				return true;
-		}
-		return false;
-	}
+    constexpr bool less(index_type& one, index_type& other) const noexcept
+    {
+        for (size_t i = 0; i < rank; ++i)
+        {
+            if (one[i] < other[i])
+                return true;
+        }
+        return false;
+    }
 
-	constexpr index_size_type linearize(const value_type& idx) const noexcept
-	{
-		// TODO: Smarter impl.
-		// Check if past-the-end
-		index_size_type multiplier = 1;
-		index_size_type res = 0;
-		if (!less(idx, boundary))
-		{
-			res = 1;
-			for (size_t i = rank; i-- > 0;)
-			{
-				res += (idx[i] - 1) * multiplier;
-				multiplier *= boundary[i];
-			}
-		}
-		else
-		{
-			for (size_t i = rank; i-- > 0;)
-			{
-				res += idx[i] * multiplier;
-				multiplier *= boundary[i];
-			}
-		}
-		return res;
-	}
+    constexpr index_size_type linearize(const value_type& idx) const noexcept
+    {
+        // TODO: Smarter impl.
+        // Check if past-the-end
+        index_size_type multiplier = 1;
+        index_size_type res = 0;
+        if (!less(idx, boundary))
+        {
+            res = 1;
+            for (size_t i = rank; i-- > 0;)
+            {
+                res += (idx[i] - 1) * multiplier;
+                multiplier *= boundary[i];
+            }
+        }
+        else
+        {
+            for (size_t i = rank; i-- > 0;)
+            {
+                res += idx[i] * multiplier;
+                multiplier *= boundary[i];
+            }
+        }
+        return res;
+    }
 
-	value_type boundary;
-	std::remove_const_t<value_type> curr;
+    value_type boundary;
+    std::remove_const_t<value_type> curr;
 };
 
 template <typename IndexType>
 bounds_iterator<IndexType> operator+(typename bounds_iterator<IndexType>::difference_type n, const bounds_iterator<IndexType>& rhs) noexcept
 {
-	return rhs + n;
+    return rhs + n;
 }
 
 //
@@ -1002,35 +1002,35 @@ bounds_iterator<IndexType> operator+(typename bounds_iterator<IndexType>::differ
 //
 namespace details
 {
-	template <typename Bounds>
-	constexpr std::enable_if_t<std::is_same<typename Bounds::mapping_type, generalized_mapping_tag>::value, typename Bounds::index_type> make_stride(const Bounds& bnd) noexcept
-	{
-		return bnd.strides();
-	}
+    template <typename Bounds>
+    constexpr std::enable_if_t<std::is_same<typename Bounds::mapping_type, generalized_mapping_tag>::value, typename Bounds::index_type> make_stride(const Bounds& bnd) noexcept
+    {
+        return bnd.strides();
+    }
 
-	// Make a stride vector from bounds, assuming contiguous memory.
-	template <typename Bounds>
-	constexpr std::enable_if_t<std::is_same<typename Bounds::mapping_type, contiguous_mapping_tag>::value, typename Bounds::index_type> make_stride(const Bounds& bnd) noexcept
-	{
-		auto extents = bnd.index_bounds();
-		typename Bounds::size_type stride[Bounds::rank] = {};
+    // Make a stride vector from bounds, assuming contiguous memory.
+    template <typename Bounds>
+    constexpr std::enable_if_t<std::is_same<typename Bounds::mapping_type, contiguous_mapping_tag>::value, typename Bounds::index_type> make_stride(const Bounds& bnd) noexcept
+    {
+        auto extents = bnd.index_bounds();
+        typename Bounds::size_type stride[Bounds::rank] = {};
 
-		stride[Bounds::rank - 1] = 1;
-		for (size_t i = 1; i < Bounds::rank; ++i)
-		{
-			stride[Bounds::rank - i - 1] = stride[Bounds::rank - i] * extents[Bounds::rank - i];
-		}
-		return{ stride };
-	}
+        stride[Bounds::rank - 1] = 1;
+        for (size_t i = 1; i < Bounds::rank; ++i)
+        {
+            stride[Bounds::rank - i - 1] = stride[Bounds::rank - i] * extents[Bounds::rank - i];
+        }
+        return{ stride };
+    }
 
-	template <typename BoundsSrc, typename BoundsDest>
-	void verifyBoundsReshape(const BoundsSrc &src, const BoundsDest &dest)
-	{
-		static_assert(is_bounds<BoundsSrc>::value && is_bounds<BoundsDest>::value, "The src type and dest type must be bounds");
-		static_assert(std::is_same<typename BoundsSrc::mapping_type, contiguous_mapping_tag>::value, "The source type must be a contiguous bounds");
-		static_assert(BoundsDest::static_size == dynamic_range || BoundsSrc::static_size == dynamic_range || BoundsDest::static_size == BoundsSrc::static_size, "The source bounds must have same size as dest bounds");
-		fail_fast_assert(src.size() == dest.size());
-	}
+    template <typename BoundsSrc, typename BoundsDest>
+    void verifyBoundsReshape(const BoundsSrc &src, const BoundsDest &dest)
+    {
+        static_assert(is_bounds<BoundsSrc>::value && is_bounds<BoundsDest>::value, "The src type and dest type must be bounds");
+        static_assert(std::is_same<typename BoundsSrc::mapping_type, contiguous_mapping_tag>::value, "The source type must be a contiguous bounds");
+        static_assert(BoundsDest::static_size == dynamic_range || BoundsSrc::static_size == dynamic_range || BoundsDest::static_size == BoundsSrc::static_size, "The source bounds must have same size as dest bounds");
+        fail_fast_assert(src.size() == dest.size());
+    }
 
 
 } // namespace details
@@ -1045,181 +1045,181 @@ template <typename ValueType, typename BoundsType>
 class basic_array_view
 {
 public:
-	static const size_t rank = BoundsType::rank;
-	using bounds_type = BoundsType;
-	using size_type = typename bounds_type::size_type;
-	using index_type = typename bounds_type::index_type;
-	using value_type = ValueType;
-	using const_value_type = std::add_const_t<value_type>;
-	using pointer = ValueType*;
-	using reference = ValueType&;
-	using iterator = std::conditional_t<std::is_same<typename BoundsType::mapping_type, contiguous_mapping_tag>::value, contiguous_array_view_iterator<basic_array_view>, general_array_view_iterator<basic_array_view>>;
-	using const_iterator = std::conditional_t<std::is_same<typename BoundsType::mapping_type, contiguous_mapping_tag>::value, contiguous_array_view_iterator<basic_array_view<const_value_type, BoundsType>>, general_array_view_iterator<basic_array_view<const_value_type, BoundsType>>>;
-	using reverse_iterator = std::reverse_iterator<iterator>;
-	using const_reverse_iterator = std::reverse_iterator<const_iterator>;
-	using sliced_type = std::conditional_t<rank == 1, value_type, basic_array_view<value_type, typename BoundsType::sliced_type>>;
+    static const size_t rank = BoundsType::rank;
+    using bounds_type = BoundsType;
+    using size_type = typename bounds_type::size_type;
+    using index_type = typename bounds_type::index_type;
+    using value_type = ValueType;
+    using const_value_type = std::add_const_t<value_type>;
+    using pointer = ValueType*;
+    using reference = ValueType&;
+    using iterator = std::conditional_t<std::is_same<typename BoundsType::mapping_type, contiguous_mapping_tag>::value, contiguous_array_view_iterator<basic_array_view>, general_array_view_iterator<basic_array_view>>;
+    using const_iterator = std::conditional_t<std::is_same<typename BoundsType::mapping_type, contiguous_mapping_tag>::value, contiguous_array_view_iterator<basic_array_view<const_value_type, BoundsType>>, general_array_view_iterator<basic_array_view<const_value_type, BoundsType>>>;
+    using reverse_iterator = std::reverse_iterator<iterator>;
+    using const_reverse_iterator = std::reverse_iterator<const_iterator>;
+    using sliced_type = std::conditional_t<rank == 1, value_type, basic_array_view<value_type, typename BoundsType::sliced_type>>;
 
 private:
-	pointer m_pdata;
-	bounds_type m_bounds;
+    pointer m_pdata;
+    bounds_type m_bounds;
 
 public:
-	constexpr bounds_type bounds() const noexcept
-	{
-		return m_bounds;
-	}
-	template <size_t Dim = 0>
-	constexpr size_type extent() const noexcept
-	{
-		static_assert(Dim < rank, "dimension should be less than rank (dimension count starts from 0)");
-		return m_bounds.template extent<Dim>();
-	}
-	constexpr size_type size() const noexcept
-	{
-		return m_bounds.size();
-	}
-	constexpr reference operator[](const index_type& idx) const
-	{
-		return m_pdata[m_bounds.linearize(idx)];
-	}
-	constexpr pointer data() const noexcept
-	{
-		return m_pdata;
-	}
-	template <bool Enabled = (rank > 1), typename Ret = std::enable_if_t<Enabled, sliced_type>>
-	constexpr Ret operator[](size_type idx) const
-	{
-		fail_fast_assert(idx < m_bounds.size(), "index is out of bounds of the array");
-		const size_type ridx = idx * m_bounds.stride();
+    constexpr bounds_type bounds() const noexcept
+    {
+        return m_bounds;
+    }
+    template <size_t Dim = 0>
+    constexpr size_type extent() const noexcept
+    {
+        static_assert(Dim < rank, "dimension should be less than rank (dimension count starts from 0)");
+        return m_bounds.template extent<Dim>();
+    }
+    constexpr size_type size() const noexcept
+    {
+        return m_bounds.size();
+    }
+    constexpr reference operator[](const index_type& idx) const
+    {
+        return m_pdata[m_bounds.linearize(idx)];
+    }
+    constexpr pointer data() const noexcept
+    {
+        return m_pdata;
+    }
+    template <bool Enabled = (rank > 1), typename Ret = std::enable_if_t<Enabled, sliced_type>>
+    constexpr Ret operator[](size_type idx) const
+    {
+        fail_fast_assert(idx < m_bounds.size(), "index is out of bounds of the array");
+        const size_type ridx = idx * m_bounds.stride();
 
-		fail_fast_assert(ridx < m_bounds.total_size(), "index is out of bounds of the underlying data");
-		return Ret {m_pdata + ridx, m_bounds.slice()};
-	}
+        fail_fast_assert(ridx < m_bounds.total_size(), "index is out of bounds of the underlying data");
+        return Ret {m_pdata + ridx, m_bounds.slice()};
+    }
 
-	constexpr operator bool () const noexcept
-	{
-		return m_pdata != nullptr;
-	}
+    constexpr operator bool () const noexcept
+    {
+        return m_pdata != nullptr;
+    }
 
-	constexpr iterator begin() const
-	{
-		return iterator {this, true};
-	}
-	constexpr iterator end() const
-	{
-		return iterator {this, false};
-	}
-	constexpr const_iterator cbegin() const
-	{
-		return const_iterator {reinterpret_cast<const basic_array_view<const value_type, bounds_type> *>(this), true};
-	}
-	constexpr const_iterator cend() const
-	{
-		return const_iterator {reinterpret_cast<const basic_array_view<const value_type, bounds_type> *>(this), false};
-	}
+    constexpr iterator begin() const
+    {
+        return iterator {this, true};
+    }
+    constexpr iterator end() const
+    {
+        return iterator {this, false};
+    }
+    constexpr const_iterator cbegin() const
+    {
+        return const_iterator {reinterpret_cast<const basic_array_view<const value_type, bounds_type> *>(this), true};
+    }
+    constexpr const_iterator cend() const
+    {
+        return const_iterator {reinterpret_cast<const basic_array_view<const value_type, bounds_type> *>(this), false};
+    }
 
-	constexpr reverse_iterator rbegin() const
-	{
-		return reverse_iterator {end()};
-	}
-	constexpr reverse_iterator rend() const
-	{
-		return reverse_iterator {begin()};
-	}
-	constexpr const_reverse_iterator crbegin() const
-	{
-		return const_reverse_iterator {cend()};
-	}
-	constexpr const_reverse_iterator crend() const
-	{
-		return const_reverse_iterator {cbegin()};
-	}
+    constexpr reverse_iterator rbegin() const
+    {
+        return reverse_iterator {end()};
+    }
+    constexpr reverse_iterator rend() const
+    {
+        return reverse_iterator {begin()};
+    }
+    constexpr const_reverse_iterator crbegin() const
+    {
+        return const_reverse_iterator {cend()};
+    }
+    constexpr const_reverse_iterator crend() const
+    {
+        return const_reverse_iterator {cbegin()};
+    }
 
-	template <typename OtherValueType, typename OtherBoundsType, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
-	constexpr bool operator== (const basic_array_view<OtherValueType, OtherBoundsType> & other) const noexcept
-	{
-		return m_bounds.size() == other.m_bounds.size() &&
-			(m_pdata == other.m_pdata || std::equal(this->begin(), this->end(), other.begin()));
-	}
+    template <typename OtherValueType, typename OtherBoundsType, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
+    constexpr bool operator== (const basic_array_view<OtherValueType, OtherBoundsType> & other) const noexcept
+    {
+        return m_bounds.size() == other.m_bounds.size() &&
+            (m_pdata == other.m_pdata || std::equal(this->begin(), this->end(), other.begin()));
+    }
 
-	template <typename OtherValueType, typename OtherBoundsType, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
-	constexpr bool operator!= (const basic_array_view<OtherValueType, OtherBoundsType> & other) const noexcept
-	{
-		return !(*this == other);
-	}
+    template <typename OtherValueType, typename OtherBoundsType, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
+    constexpr bool operator!= (const basic_array_view<OtherValueType, OtherBoundsType> & other) const noexcept
+    {
+        return !(*this == other);
+    }
 
-	template <typename OtherValueType, typename OtherBoundsType, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
-	constexpr bool operator< (const basic_array_view<OtherValueType, OtherBoundsType> & other) const noexcept
-	{
-		return std::lexicographical_compare(this->begin(), this->end(), other.begin(), other.end());
-	}
+    template <typename OtherValueType, typename OtherBoundsType, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
+    constexpr bool operator< (const basic_array_view<OtherValueType, OtherBoundsType> & other) const noexcept
+    {
+        return std::lexicographical_compare(this->begin(), this->end(), other.begin(), other.end());
+    }
 
-	template <typename OtherValueType, typename OtherBoundsType, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
-	constexpr bool operator<= (const basic_array_view<OtherValueType, OtherBoundsType> & other) const noexcept
-	{
-		return !(other < *this);
-	}
+    template <typename OtherValueType, typename OtherBoundsType, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
+    constexpr bool operator<= (const basic_array_view<OtherValueType, OtherBoundsType> & other) const noexcept
+    {
+        return !(other < *this);
+    }
 
-	template <typename OtherValueType, typename OtherBoundsType, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
-	constexpr bool operator> (const basic_array_view<OtherValueType, OtherBoundsType> & other) const noexcept
-	{
-		return (other < *this);
-	}
+    template <typename OtherValueType, typename OtherBoundsType, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
+    constexpr bool operator> (const basic_array_view<OtherValueType, OtherBoundsType> & other) const noexcept
+    {
+        return (other < *this);
+    }
 
-	template <typename OtherValueType, typename OtherBoundsType, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
-	constexpr bool operator>= (const basic_array_view<OtherValueType, OtherBoundsType> & other) const noexcept
-	{
-		return !(*this < other);
-	}
+    template <typename OtherValueType, typename OtherBoundsType, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
+    constexpr bool operator>= (const basic_array_view<OtherValueType, OtherBoundsType> & other) const noexcept
+    {
+        return !(*this < other);
+    }
 
 public:
-	template <typename OtherValueType, typename OtherBounds,
-		typename Dummy = std::enable_if_t<std::is_convertible<OtherValueType(*)[], value_type(*)[]>::value
-			&& std::is_convertible<OtherBounds, bounds_type>::value>>
-	constexpr basic_array_view(const basic_array_view<OtherValueType, OtherBounds> & other ) noexcept
-		: m_pdata(other.m_pdata), m_bounds(other.m_bounds)
-	{
-	}
+    template <typename OtherValueType, typename OtherBounds,
+        typename Dummy = std::enable_if_t<std::is_convertible<OtherValueType(*)[], value_type(*)[]>::value
+            && std::is_convertible<OtherBounds, bounds_type>::value>>
+    constexpr basic_array_view(const basic_array_view<OtherValueType, OtherBounds> & other ) noexcept
+        : m_pdata(other.m_pdata), m_bounds(other.m_bounds)
+    {
+    }
 protected:
 
-	constexpr basic_array_view(pointer data, bounds_type bound) noexcept
-		: m_pdata(data)
-		, m_bounds(std::move(bound))
-	{
-		fail_fast_assert((m_bounds.size() > 0 && data != nullptr) || m_bounds.size() == 0);
-	}
-	template <typename T>
-	constexpr basic_array_view(T *data, std::enable_if_t<std::is_same<value_type, std::remove_all_extents_t<T>>::value, bounds_type> bound) noexcept
-		: m_pdata(reinterpret_cast<pointer>(data))
-		, m_bounds(std::move(bound))
-	{
-		fail_fast_assert((m_bounds.size() > 0 && data != nullptr) || m_bounds.size() == 0);
-	}
-	template <typename DestBounds>
-	constexpr basic_array_view<value_type, DestBounds> as_array_view(const DestBounds &bounds)
-	{
-		details::verifyBoundsReshape(m_bounds, bounds);
-		return {m_pdata, bounds};
-	}
+    constexpr basic_array_view(pointer data, bounds_type bound) noexcept
+        : m_pdata(data)
+        , m_bounds(std::move(bound))
+    {
+        fail_fast_assert((m_bounds.size() > 0 && data != nullptr) || m_bounds.size() == 0);
+    }
+    template <typename T>
+    constexpr basic_array_view(T *data, std::enable_if_t<std::is_same<value_type, std::remove_all_extents_t<T>>::value, bounds_type> bound) noexcept
+        : m_pdata(reinterpret_cast<pointer>(data))
+        , m_bounds(std::move(bound))
+    {
+        fail_fast_assert((m_bounds.size() > 0 && data != nullptr) || m_bounds.size() == 0);
+    }
+    template <typename DestBounds>
+    constexpr basic_array_view<value_type, DestBounds> as_array_view(const DestBounds &bounds)
+    {
+        details::verifyBoundsReshape(m_bounds, bounds);
+        return {m_pdata, bounds};
+    }
 private:
 
-	friend iterator;
-	friend const_iterator;
-	template <typename ValueType2, typename BoundsType2>
-	friend class basic_array_view;
+    friend iterator;
+    friend const_iterator;
+    template <typename ValueType2, typename BoundsType2>
+    friend class basic_array_view;
 };
 
 template <std::ptrdiff_t DimSize = dynamic_range>
 struct dim
 {
-	static const std::ptrdiff_t value = DimSize;
+    static const std::ptrdiff_t value = DimSize;
 };
 template <>
 struct dim<dynamic_range>
 {
-	static const std::ptrdiff_t value = dynamic_range;
-	const std::ptrdiff_t dvalue;
-	dim(std::ptrdiff_t size) : dvalue(size) {}
+    static const std::ptrdiff_t value = dynamic_range;
+    const std::ptrdiff_t dvalue;
+    dim(std::ptrdiff_t size) : dvalue(size) {}
 };
 
 template <typename ValueType, std::ptrdiff_t FirstDimension = dynamic_range, std::ptrdiff_t... RestDimensions>
@@ -1230,89 +1230,89 @@ class strided_array_view;
 
 namespace details
 {
-	template <typename T, typename = std::true_type>
-	struct ArrayViewTypeTraits
-	{
-		using value_type = T;
-		using size_type = size_t;
-	};
+    template <typename T, typename = std::true_type>
+    struct ArrayViewTypeTraits
+    {
+        using value_type = T;
+        using size_type = size_t;
+    };
 
-	template <typename Traits>
-	struct ArrayViewTypeTraits<Traits, typename std::is_reference<typename Traits::array_view_traits &>::type>
-	{
-		using value_type = typename Traits::array_view_traits::value_type;
-		using size_type = typename Traits::array_view_traits::size_type;
-	};
+    template <typename Traits>
+    struct ArrayViewTypeTraits<Traits, typename std::is_reference<typename Traits::array_view_traits &>::type>
+    {
+        using value_type = typename Traits::array_view_traits::value_type;
+        using size_type = typename Traits::array_view_traits::size_type;
+    };
 
-	template <typename T, std::ptrdiff_t... Ranks>
-	struct ArrayViewArrayTraits {
-		using type = array_view<T, Ranks...>;
-		using value_type = T;
-		using bounds_type = static_bounds<Ranks...>;
-		using pointer = T*;
-		using reference = T&;
-	};
-	template <typename T, std::ptrdiff_t N, std::ptrdiff_t... Ranks>
-	struct ArrayViewArrayTraits<T[N], Ranks...> : ArrayViewArrayTraits<T, Ranks..., N> {};
+    template <typename T, std::ptrdiff_t... Ranks>
+    struct ArrayViewArrayTraits {
+        using type = array_view<T, Ranks...>;
+        using value_type = T;
+        using bounds_type = static_bounds<Ranks...>;
+        using pointer = T*;
+        using reference = T&;
+    };
+    template <typename T, std::ptrdiff_t N, std::ptrdiff_t... Ranks>
+    struct ArrayViewArrayTraits<T[N], Ranks...> : ArrayViewArrayTraits<T, Ranks..., N> {};
 
-	template <typename BoundsType>
-	BoundsType newBoundsHelperImpl(std::ptrdiff_t totalSize, std::true_type) // dynamic size
-	{
-		fail_fast_assert(totalSize <= PTRDIFF_MAX);
-		return BoundsType{totalSize};
-	}
-	template <typename BoundsType>
-	BoundsType newBoundsHelperImpl(std::ptrdiff_t totalSize, std::false_type) // static size
-	{
-		fail_fast_assert(BoundsType::static_size == totalSize);
-		return {};
-	}
-	template <typename BoundsType>
-	BoundsType newBoundsHelper(std::ptrdiff_t totalSize)
-	{
-		static_assert(BoundsType::dynamic_rank <= 1, "dynamic rank must less or equal to 1");
-		return newBoundsHelperImpl<BoundsType>(totalSize, std::integral_constant<bool, BoundsType::dynamic_rank == 1>());
-	}
-	
-	struct Sep{};
-	
-	template <typename T, typename... Args>
-	T static_as_array_view_helper(Sep, Args... args)
-	{
-		return T{static_cast<typename T::size_type>(args)...};
-	}
-	template <typename T, typename Arg, typename... Args>
-	std::enable_if_t<!std::is_same<Arg, dim<dynamic_range>>::value && !std::is_same<Arg, Sep>::value, T> static_as_array_view_helper(Arg, Args... args)
-	{
-		return static_as_array_view_helper<T>(args...);
-	}
-	template <typename T, typename... Args>
-	T static_as_array_view_helper(dim<dynamic_range> val, Args ... args)
-	{
-		return static_as_array_view_helper<T>(args..., val.dvalue);
-	}
+    template <typename BoundsType>
+    BoundsType newBoundsHelperImpl(std::ptrdiff_t totalSize, std::true_type) // dynamic size
+    {
+        fail_fast_assert(totalSize <= PTRDIFF_MAX);
+        return BoundsType{totalSize};
+    }
+    template <typename BoundsType>
+    BoundsType newBoundsHelperImpl(std::ptrdiff_t totalSize, std::false_type) // static size
+    {
+        fail_fast_assert(BoundsType::static_size == totalSize);
+        return {};
+    }
+    template <typename BoundsType>
+    BoundsType newBoundsHelper(std::ptrdiff_t totalSize)
+    {
+        static_assert(BoundsType::dynamic_rank <= 1, "dynamic rank must less or equal to 1");
+        return newBoundsHelperImpl<BoundsType>(totalSize, std::integral_constant<bool, BoundsType::dynamic_rank == 1>());
+    }
+    
+    struct Sep{};
+    
+    template <typename T, typename... Args>
+    T static_as_array_view_helper(Sep, Args... args)
+    {
+        return T{static_cast<typename T::size_type>(args)...};
+    }
+    template <typename T, typename Arg, typename... Args>
+    std::enable_if_t<!std::is_same<Arg, dim<dynamic_range>>::value && !std::is_same<Arg, Sep>::value, T> static_as_array_view_helper(Arg, Args... args)
+    {
+        return static_as_array_view_helper<T>(args...);
+    }
+    template <typename T, typename... Args>
+    T static_as_array_view_helper(dim<dynamic_range> val, Args ... args)
+    {
+        return static_as_array_view_helper<T>(args..., val.dvalue);
+    }
 
-	template <typename ...Dimensions>
-	struct static_as_array_view_static_bounds_helper
-	{
-		using type = static_bounds<(Dimensions::value)...>;
-	};
+    template <typename ...Dimensions>
+    struct static_as_array_view_static_bounds_helper
+    {
+        using type = static_bounds<(Dimensions::value)...>;
+    };
 
-	template <typename T>
-	struct is_array_view_oracle : std::false_type
-	{};
-
-	template <typename ValueType, std::ptrdiff_t FirstDimension, std::ptrdiff_t... RestDimensions>
-	struct is_array_view_oracle<array_view<ValueType, FirstDimension, RestDimensions...>> : std::true_type
-	{};
-	
-    template <typename ValueType, std::ptrdiff_t Rank>
-	struct is_array_view_oracle<strided_array_view<ValueType, Rank>> : std::true_type
-	{};
-	
     template <typename T>
-	struct is_array_view : is_array_view_oracle<std::remove_cv_t<T>>
-	{};
+    struct is_array_view_oracle : std::false_type
+    {};
+
+    template <typename ValueType, std::ptrdiff_t FirstDimension, std::ptrdiff_t... RestDimensions>
+    struct is_array_view_oracle<array_view<ValueType, FirstDimension, RestDimensions...>> : std::true_type
+    {};
+    
+    template <typename ValueType, std::ptrdiff_t Rank>
+    struct is_array_view_oracle<strided_array_view<ValueType, Rank>> : std::true_type
+    {};
+    
+    template <typename T>
+    struct is_array_view : is_array_view_oracle<std::remove_cv_t<T>>
+    {};
 
 }
 
@@ -1320,265 +1320,266 @@ namespace details
 template <typename ValueType, std::ptrdiff_t FirstDimension, std::ptrdiff_t... RestDimensions>
 class array_view : public basic_array_view <ValueType, static_bounds <FirstDimension, RestDimensions...>>
 {
-	template <typename ValueType2, std::ptrdiff_t FirstDimension2, std::ptrdiff_t... RestDimensions2>
-	friend class array_view;
+    template <typename ValueType2, std::ptrdiff_t FirstDimension2,
+              std::ptrdiff_t... RestDimensions2>
+    friend class array_view;
 
-	using Base = basic_array_view<ValueType, static_bounds<FirstDimension, RestDimensions...>>;
+    using Base = basic_array_view<ValueType, static_bounds<FirstDimension, RestDimensions...>>;
 
 public:
-	using typename Base::bounds_type;
-	using typename Base::size_type;
-	using typename Base::pointer;
-	using typename Base::value_type;
-	using typename Base::index_type;
-	using typename Base::iterator;
-	using typename Base::const_iterator;
-	using typename Base::reference;
-	using Base::rank;
+    using typename Base::bounds_type;
+    using typename Base::size_type;
+    using typename Base::pointer;
+    using typename Base::value_type;
+    using typename Base::index_type;
+    using typename Base::iterator;
+    using typename Base::const_iterator;
+    using typename Base::reference;
+    using Base::rank;
 
 public:
-	// basic
+    // basic
     constexpr array_view(pointer ptr, size_type size) : Base(ptr, bounds_type{ size })
     {}
 
     constexpr array_view(pointer ptr, bounds_type bounds) : Base(ptr, std::move(bounds))
     {}
 
-	constexpr array_view(std::nullptr_t) : Base(nullptr, bounds_type{})
-	{}
+    constexpr array_view(std::nullptr_t) : Base(nullptr, bounds_type{})
+    {}
 
-	constexpr array_view(std::nullptr_t, size_type size) : Base(nullptr, bounds_type{})
-	{
-		fail_fast_assert(size == 0);
-	}
+    constexpr array_view(std::nullptr_t, size_type size) : Base(nullptr, bounds_type{})
+    {
+        fail_fast_assert(size == 0);
+    }
 
-	// default
-	template <std::ptrdiff_t DynamicRank = bounds_type::dynamic_rank, typename = std::enable_if_t<DynamicRank != 0>>
-	constexpr array_view() : Base(nullptr, bounds_type())
-	{}
+    // default
+    template <std::ptrdiff_t DynamicRank = bounds_type::dynamic_rank, typename = std::enable_if_t<DynamicRank != 0>>
+    constexpr array_view() : Base(nullptr, bounds_type())
+    {}
 
-	// from n-dimensions dynamic array (e.g. new int[m][4]) (precedence will be lower than the 1-dimension pointer)
-	template <typename T, typename Helper = details::ArrayViewArrayTraits<T, dynamic_range>
+    // from n-dimensions dynamic array (e.g. new int[m][4]) (precedence will be lower than the 1-dimension pointer)
+    template <typename T, typename Helper = details::ArrayViewArrayTraits<T, dynamic_range>
         /*typename Dummy = std::enable_if_t<std::is_convertible<Helper::value_type (*)[], typename Base::value_type (*)[]>::value>*/>
-	constexpr array_view(T* const& data, size_type size) : Base(data, typename Helper::bounds_type{size})
-	{}
+    constexpr array_view(T* const& data, size_type size) : Base(data, typename Helper::bounds_type{size})
+    {}
 
-	// from n-dimensions static array
-	template <typename T, size_t N, typename Helper = details::ArrayViewArrayTraits<T, N>,
+    // from n-dimensions static array
+    template <typename T, size_t N, typename Helper = details::ArrayViewArrayTraits<T, N>,
         typename = std::enable_if_t<std::is_convertible<typename Helper::value_type(*)[], typename Base::value_type(*)[]>::value>>
-	constexpr array_view (T (&arr)[N]) : Base(arr, typename Helper::bounds_type())
-	{}
+    constexpr array_view (T (&arr)[N]) : Base(arr, typename Helper::bounds_type())
+    {}
 
-	// from n-dimensions static array with size
-	template <typename T, size_t N, typename Helper = details::ArrayViewArrayTraits<T, N>,
-		typename = std::enable_if_t<std::is_convertible<typename Helper::value_type(*)[], typename Base::value_type(*)[]>::value>
+    // from n-dimensions static array with size
+    template <typename T, size_t N, typename Helper = details::ArrayViewArrayTraits<T, N>,
+        typename = std::enable_if_t<std::is_convertible<typename Helper::value_type(*)[], typename Base::value_type(*)[]>::value>
     >
     constexpr array_view(T(&arr)[N], size_type size) : Base(arr, typename Helper::bounds_type{size})
-	{
-		fail_fast_assert(size <= N);
-	}
+    {
+        fail_fast_assert(size <= N);
+    }
 
-	// from std array
-	template <size_t N, 
+    // from std array
+    template <size_t N, 
        typename Dummy = std::enable_if_t<std::is_convertible<static_bounds<N>, typename Base::bounds_type>::value>
     >
-	constexpr array_view (std::array<std::remove_const_t<value_type>, N> & arr) : Base(arr.data(), static_bounds<N>())
-	{}
+    constexpr array_view (std::array<std::remove_const_t<value_type>, N> & arr) : Base(arr.data(), static_bounds<N>())
+    {}
 
-	template <size_t N,
+    template <size_t N,
         typename Dummy = std::enable_if_t<std::is_convertible<static_bounds<N>, typename Base::bounds_type>::value
         && std::is_const<value_type>::value>
     >
-	constexpr array_view (const std::array<std::remove_const_t<value_type>, N> & arr) : Base(arr.data(), static_bounds<N>())
-	{}
+    constexpr array_view (const std::array<std::remove_const_t<value_type>, N> & arr) : Base(arr.data(), static_bounds<N>())
+    {}
     
-	// from begin, end pointers. We don't provide iterator pair since no way to guarantee the contiguity 
-	template <typename Ptr,
-		typename Dummy = std::enable_if_t<std::is_convertible<Ptr, pointer>::value
-		&& details::LessThan<Base::bounds_type::dynamic_rank, 2>::value>
+    // from begin, end pointers. We don't provide iterator pair since no way to guarantee the contiguity 
+    template <typename Ptr,
+        typename Dummy = std::enable_if_t<std::is_convertible<Ptr, pointer>::value
+        && details::LessThan<Base::bounds_type::dynamic_rank, 2>::value>
     > // remove literal 0 case
-	constexpr array_view (pointer begin, Ptr end) : Base(begin, details::newBoundsHelper<typename Base::bounds_type>(static_cast<pointer>(end) - begin))
-	{}
+    constexpr array_view (pointer begin, Ptr end) : Base(begin, details::newBoundsHelper<typename Base::bounds_type>(static_cast<pointer>(end) - begin))
+    {}
 
-	// from containers. It must has .size() and .data() two function signatures
-	template <typename Cont, typename DataType = typename Cont::value_type,
-		typename Dummy = std::enable_if_t<!details::is_array_view<Cont>::value
-		&& std::is_convertible<DataType (*)[], typename Base::value_type (*)[]>::value
-		&& std::is_same<std::decay_t<decltype(std::declval<Cont>().size(), *std::declval<Cont>().data())>, DataType>::value>
-	>
-	constexpr array_view (Cont& cont) : Base(static_cast<pointer>(cont.data()), details::newBoundsHelper<typename Base::bounds_type>(cont.size()))
-	{}
+    // from containers. It must has .size() and .data() two function signatures
+    template <typename Cont, typename DataType = typename Cont::value_type,
+        typename Dummy = std::enable_if_t<!details::is_array_view<Cont>::value
+        && std::is_convertible<DataType (*)[], typename Base::value_type (*)[]>::value
+        && std::is_same<std::decay_t<decltype(std::declval<Cont>().size(), *std::declval<Cont>().data())>, DataType>::value>
+    >
+    constexpr array_view (Cont& cont) : Base(static_cast<pointer>(cont.data()), details::newBoundsHelper<typename Base::bounds_type>(cont.size()))
+    {}
 
-	constexpr array_view(const array_view &) = default;
+    constexpr array_view(const array_view &) = default;
 
-	// convertible
-	template <typename OtherValueType, std::ptrdiff_t... OtherDimensions,
-		typename BaseType = basic_array_view<ValueType, static_bounds<FirstDimension, RestDimensions...>>,
-		typename OtherBaseType = basic_array_view<OtherValueType, static_bounds<OtherDimensions...>>,
-		typename Dummy = std::enable_if_t<std::is_convertible<OtherBaseType, BaseType>::value>
-	>
-	constexpr array_view(const array_view<OtherValueType, OtherDimensions...> &av)
+    // convertible
+    template <typename OtherValueType, std::ptrdiff_t... OtherDimensions,
+        typename BaseType = basic_array_view<ValueType, static_bounds<FirstDimension, RestDimensions...>>,
+        typename OtherBaseType = basic_array_view<OtherValueType, static_bounds<OtherDimensions...>>,
+        typename Dummy = std::enable_if_t<std::is_convertible<OtherBaseType, BaseType>::value>
+    >
+    constexpr array_view(const array_view<OtherValueType, OtherDimensions...> &av)
         : Base(static_cast<const typename array_view<OtherValueType, OtherDimensions...>::Base&>(av))
     {}
 
-	// reshape
+    // reshape
     // DimCount here is a workaround for a bug in MSVC 2015
     template <typename... Dimensions2, size_t DimCount = sizeof...(Dimensions2), typename = std::enable_if_t<(DimCount > 0)>>
     constexpr array_view<ValueType, Dimensions2::value...> as_array_view(Dimensions2... dims)
-	{
-		using BoundsType = typename array_view<ValueType, (Dimensions2::value)...>::bounds_type;
-		auto tobounds = details::static_as_array_view_helper<BoundsType>(dims..., details::Sep{});
-		details::verifyBoundsReshape(this->bounds(), tobounds);
-		return {this->data(), tobounds};
-	}
+    {
+        using BoundsType = typename array_view<ValueType, (Dimensions2::value)...>::bounds_type;
+        auto tobounds = details::static_as_array_view_helper<BoundsType>(dims..., details::Sep{});
+        details::verifyBoundsReshape(this->bounds(), tobounds);
+        return {this->data(), tobounds};
+    }
 
-	// to bytes array
-	template <bool Enabled = std::is_standard_layout<std::decay_t<ValueType>>::value>
-	auto as_bytes() const noexcept -> array_view<const byte>
-	{
-		static_assert(Enabled, "The value_type of array_view must be standarded layout");
-		return { reinterpret_cast<const byte*>(this->data()), this->bytes() };
-	}
+    // to bytes array
+    template <bool Enabled = std::is_standard_layout<std::decay_t<ValueType>>::value>
+    auto as_bytes() const noexcept -> array_view<const byte>
+    {
+        static_assert(Enabled, "The value_type of array_view must be standarded layout");
+        return { reinterpret_cast<const byte*>(this->data()), this->bytes() };
+    }
 
-	template <bool Enabled = std::is_standard_layout<std::decay_t<ValueType>>::value>
-	auto as_writeable_bytes() const noexcept -> array_view<byte>
-	{
-		static_assert(Enabled, "The value_type of array_view must be standarded layout");
-		return { reinterpret_cast<byte*>(this->data()), this->bytes() };
-	}
+    template <bool Enabled = std::is_standard_layout<std::decay_t<ValueType>>::value>
+    auto as_writeable_bytes() const noexcept -> array_view<byte>
+    {
+        static_assert(Enabled, "The value_type of array_view must be standarded layout");
+        return { reinterpret_cast<byte*>(this->data()), this->bytes() };
+    }
 
     // from bytes array
-	template<typename U, bool IsByte = std::is_same<value_type, const byte>::value, typename = std::enable_if_t<IsByte && sizeof...(RestDimensions) == 0>>
-	constexpr auto as_array_view() const noexcept -> array_view<const U, (Base::bounds_type::static_size != dynamic_range ? static_cast<std::ptrdiff_t>(static_cast<size_t>(Base::bounds_type::static_size) / sizeof(U)) : dynamic_range)>
-	{
-		static_assert(std::is_standard_layout<U>::value && (Base::bounds_type::static_size == dynamic_range || Base::bounds_type::static_size % static_cast<size_type>(sizeof(U)) == 0),
-			"Target type must be standard layout and its size must match the byte array size");
-		fail_fast_assert((this->bytes() % sizeof(U)) == 0 && (this->bytes() / sizeof(U)) < PTRDIFF_MAX);
-		return { reinterpret_cast<const U*>(this->data()), this->bytes() / static_cast<size_type>(sizeof(U)) };
-	}
+    template<typename U, bool IsByte = std::is_same<value_type, const byte>::value, typename = std::enable_if_t<IsByte && sizeof...(RestDimensions) == 0>>
+    constexpr auto as_array_view() const noexcept -> array_view<const U, (Base::bounds_type::static_size != dynamic_range ? static_cast<std::ptrdiff_t>(static_cast<size_t>(Base::bounds_type::static_size) / sizeof(U)) : dynamic_range)>
+    {
+        static_assert(std::is_standard_layout<U>::value && (Base::bounds_type::static_size == dynamic_range || Base::bounds_type::static_size % static_cast<size_type>(sizeof(U)) == 0),
+            "Target type must be standard layout and its size must match the byte array size");
+        fail_fast_assert((this->bytes() % sizeof(U)) == 0 && (this->bytes() / sizeof(U)) < PTRDIFF_MAX);
+        return { reinterpret_cast<const U*>(this->data()), this->bytes() / static_cast<size_type>(sizeof(U)) };
+    }
 
-	template<typename U, bool IsByte = std::is_same<value_type, byte>::value, typename = std::enable_if_t<IsByte && sizeof...(RestDimensions) == 0>>
-	constexpr auto as_array_view() const noexcept -> array_view<U, (Base::bounds_type::static_size != dynamic_range ? static_cast<ptrdiff_t>(static_cast<size_t>(Base::bounds_type::static_size) / sizeof(U)) : dynamic_range)>
-	{
-		static_assert(std::is_standard_layout<U>::value && (Base::bounds_type::static_size == dynamic_range || Base::bounds_type::static_size % static_cast<size_t>(sizeof(U)) == 0),
-			"Target type must be standard layout and its size must match the byte array size");
-		fail_fast_assert((this->bytes() % sizeof(U)) == 0);
-		return { reinterpret_cast<U*>(this->data()), this->bytes() / static_cast<size_type>(sizeof(U)) };
-	}
+    template<typename U, bool IsByte = std::is_same<value_type, byte>::value, typename = std::enable_if_t<IsByte && sizeof...(RestDimensions) == 0>>
+    constexpr auto as_array_view() const noexcept -> array_view<U, (Base::bounds_type::static_size != dynamic_range ? static_cast<ptrdiff_t>(static_cast<size_t>(Base::bounds_type::static_size) / sizeof(U)) : dynamic_range)>
+    {
+        static_assert(std::is_standard_layout<U>::value && (Base::bounds_type::static_size == dynamic_range || Base::bounds_type::static_size % static_cast<size_t>(sizeof(U)) == 0),
+            "Target type must be standard layout and its size must match the byte array size");
+        fail_fast_assert((this->bytes() % sizeof(U)) == 0);
+        return { reinterpret_cast<U*>(this->data()), this->bytes() / static_cast<size_type>(sizeof(U)) };
+    }
 
-	// section on linear space
-	template<std::ptrdiff_t Count>
-	constexpr array_view<ValueType, Count> first() const noexcept
-	{
-		static_assert(bounds_type::static_size == dynamic_range || Count <= bounds_type::static_size, "Index is out of bound");
-		fail_fast_assert(bounds_type::static_size != dynamic_range || Count <= this->size()); // ensures we only check condition when needed
-		return { this->data(), Count };
-	}
+    // section on linear space
+    template<std::ptrdiff_t Count>
+    constexpr array_view<ValueType, Count> first() const noexcept
+    {
+        static_assert(bounds_type::static_size == dynamic_range || Count <= bounds_type::static_size, "Index is out of bound");
+        fail_fast_assert(bounds_type::static_size != dynamic_range || Count <= this->size()); // ensures we only check condition when needed
+        return { this->data(), Count };
+    }
 
-	constexpr array_view<ValueType, dynamic_range> first(size_type count) const noexcept
-	{
-		fail_fast_assert(count <= this->size());
-		return { this->data(), count };
-	}
+    constexpr array_view<ValueType, dynamic_range> first(size_type count) const noexcept
+    {
+        fail_fast_assert(count <= this->size());
+        return { this->data(), count };
+    }
 
-	template<std::ptrdiff_t Count>
-	constexpr array_view<ValueType, Count> last() const noexcept
-	{
-		static_assert(bounds_type::static_size == dynamic_range || Count <= bounds_type::static_size, "Index is out of bound");
-		fail_fast_assert(bounds_type::static_size != dynamic_range || Count <= this->size());
-		return { this->data() + this->size() - Count, Count };
-	}
+    template<std::ptrdiff_t Count>
+    constexpr array_view<ValueType, Count> last() const noexcept
+    {
+        static_assert(bounds_type::static_size == dynamic_range || Count <= bounds_type::static_size, "Index is out of bound");
+        fail_fast_assert(bounds_type::static_size != dynamic_range || Count <= this->size());
+        return { this->data() + this->size() - Count, Count };
+    }
 
-	constexpr array_view<ValueType, dynamic_range> last(size_type count) const noexcept
-	{
-		fail_fast_assert(count <= this->size());
-		return { this->data() + this->size() - count, count };
-	}
+    constexpr array_view<ValueType, dynamic_range> last(size_type count) const noexcept
+    {
+        fail_fast_assert(count <= this->size());
+        return { this->data() + this->size() - count, count };
+    }
 
-	template<std::ptrdiff_t Offset, std::ptrdiff_t Count>
-	constexpr array_view<ValueType, Count> sub() const noexcept
-	{
-		static_assert(bounds_type::static_size == dynamic_range || ((Offset == 0 || Offset <= bounds_type::static_size) && Offset + Count <= bounds_type::static_size), "Index is out of bound");
-		fail_fast_assert(bounds_type::static_size != dynamic_range || ((Offset == 0 || Offset <= this->size()) && Offset + Count <= this->size()));
-		return { this->data() + Offset, Count };
-	}
+    template<std::ptrdiff_t Offset, std::ptrdiff_t Count>
+    constexpr array_view<ValueType, Count> sub() const noexcept
+    {
+        static_assert(bounds_type::static_size == dynamic_range || ((Offset == 0 || Offset <= bounds_type::static_size) && Offset + Count <= bounds_type::static_size), "Index is out of bound");
+        fail_fast_assert(bounds_type::static_size != dynamic_range || ((Offset == 0 || Offset <= this->size()) && Offset + Count <= this->size()));
+        return { this->data() + Offset, Count };
+    }
 
-	constexpr array_view<ValueType, dynamic_range> sub(size_type offset, size_type count = dynamic_range) const noexcept
-	{
-		fail_fast_assert((offset == 0 || offset <= this->size()) && (count == dynamic_range || (offset + count) <= this->size()));
-		return { this->data() + offset, count == dynamic_range ? this->length() - offset : count };
-	}
+    constexpr array_view<ValueType, dynamic_range> sub(size_type offset, size_type count = dynamic_range) const noexcept
+    {
+        fail_fast_assert((offset == 0 || offset <= this->size()) && (count == dynamic_range || (offset + count) <= this->size()));
+        return { this->data() + offset, count == dynamic_range ? this->length() - offset : count };
+    }
 
-	// size
-	constexpr size_type length() const noexcept
-	{
-		return this->size();
-	}
+    // size
+    constexpr size_type length() const noexcept
+    {
+        return this->size();
+    }
 
-	constexpr size_type used_length() const noexcept
-	{
-		return length();
-	}
+    constexpr size_type used_length() const noexcept
+    {
+        return length();
+    }
 
-	constexpr size_type bytes() const noexcept
-	{
-		return sizeof(value_type) * this->size();
-	}
+    constexpr size_type bytes() const noexcept
+    {
+        return sizeof(value_type) * this->size();
+    }
 
-	constexpr size_type used_bytes() const noexcept
-	{
-		return bytes();
-	}
+    constexpr size_type used_bytes() const noexcept
+    {
+        return bytes();
+    }
 
-	// section
-	constexpr strided_array_view<ValueType, rank> section(index_type origin, index_type extents) const
-	{
-		size_type size = this->bounds().total_size() - this->bounds().linearize(origin);
-		return{ &this->operator[](origin), size, strided_bounds<rank> {extents, details::make_stride(Base::bounds())} };
-	}
-	
-		constexpr reference operator[](const index_type& idx) const
-	{
-		return Base::operator[](idx);
-	}
-	
-		template <bool Enabled = (rank > 1), typename Dummy = std::enable_if_t<Enabled>>
-	constexpr array_view<ValueType, RestDimensions...> operator[](size_type idx) const
-	{
-		auto ret = Base::operator[](idx);
-		return{ ret.data(), ret.bounds() };
-	}
+    // section
+    constexpr strided_array_view<ValueType, rank> section(index_type origin, index_type extents) const
+    {
+        size_type size = this->bounds().total_size() - this->bounds().linearize(origin);
+        return{ &this->operator[](origin), size, strided_bounds<rank> {extents, details::make_stride(Base::bounds())} };
+    }
+    
+        constexpr reference operator[](const index_type& idx) const
+    {
+        return Base::operator[](idx);
+    }
+    
+        template <bool Enabled = (rank > 1), typename Dummy = std::enable_if_t<Enabled>>
+    constexpr array_view<ValueType, RestDimensions...> operator[](size_type idx) const
+    {
+        auto ret = Base::operator[](idx);
+        return{ ret.data(), ret.bounds() };
+    }
 
-	using Base::operator==;
-	using Base::operator!=;
-	using Base::operator<;
-	using Base::operator<=;
-	using Base::operator>;
-	using Base::operator>=;
+    using Base::operator==;
+    using Base::operator!=;
+    using Base::operator<;
+    using Base::operator<=;
+    using Base::operator>;
+    using Base::operator>=;
 };
 
 template <typename T, std::ptrdiff_t... Dimensions>
 constexpr auto as_array_view(T* const& ptr, dim<Dimensions>... args) -> array_view<std::remove_all_extents_t<T>, Dimensions...>
 {
-	return {reinterpret_cast<std::remove_all_extents_t<T>*>(ptr), details::static_as_array_view_helper<static_bounds<Dimensions...>>(args..., details::Sep{})};
+    return {reinterpret_cast<std::remove_all_extents_t<T>*>(ptr), details::static_as_array_view_helper<static_bounds<Dimensions...>>(args..., details::Sep{})};
 }
 
 template <typename T>
 constexpr auto as_array_view (T* arr, std::ptrdiff_t len) -> typename details::ArrayViewArrayTraits<T, dynamic_range>::type
 {
-	return {reinterpret_cast<std::remove_all_extents_t<T>*>(arr), len};
+    return {reinterpret_cast<std::remove_all_extents_t<T>*>(arr), len};
 }
 
 template <typename T, size_t N>
 constexpr auto as_array_view (T (&arr)[N]) -> typename details::ArrayViewArrayTraits<T, N>::type
 {
-	return {arr};
+    return {arr};
 }
 
 template <typename T, size_t N>
 constexpr array_view<const T, N> as_array_view(const std::array<T, N> &arr)
 {
-	return {arr};
+    return {arr};
 }
 
 template <typename T, size_t N>
@@ -1587,374 +1588,374 @@ constexpr array_view<const T, N> as_array_view(const std::array<T, N> &&) = dele
 template <typename T, size_t N>
 constexpr array_view<T, N> as_array_view(std::array<T, N> &arr)
 {
-	return {arr};
+    return {arr};
 }
 
 template <typename T>
 constexpr array_view<T, dynamic_range> as_array_view(T *begin, T *end)
 {
-	return {begin, end};
+    return {begin, end};
 }
 
 template <typename Cont>
 constexpr auto as_array_view(Cont &arr) -> std::enable_if_t<!details::is_array_view<std::decay_t<Cont>>::value,
-	array_view<std::remove_reference_t<decltype(arr.size(), *arr.data())>, dynamic_range>>
+    array_view<std::remove_reference_t<decltype(arr.size(), *arr.data())>, dynamic_range>>
 {
     fail_fast_assert(arr.size() < PTRDIFF_MAX);
-	return {arr.data(), static_cast<std::ptrdiff_t>(arr.size())};
+    return {arr.data(), static_cast<std::ptrdiff_t>(arr.size())};
 }
 
 template <typename Cont>
 constexpr auto as_array_view(Cont &&arr) -> std::enable_if_t<!details::is_array_view<std::decay_t<Cont>>::value,
-	array_view<std::remove_reference_t<decltype(arr.size(), *arr.data())>, dynamic_range>> = delete;
+    array_view<std::remove_reference_t<decltype(arr.size(), *arr.data())>, dynamic_range>> = delete;
 
 template <typename ValueType, size_t Rank>
 class strided_array_view : public basic_array_view<ValueType, strided_bounds<Rank>>
 {
-	using Base = basic_array_view<ValueType, strided_bounds<Rank>>;
+    using Base = basic_array_view<ValueType, strided_bounds<Rank>>;
 
-	template<typename OtherValue, size_t OtherRank>
-	friend class strided_array_view;
+    template<typename OtherValue, size_t OtherRank>
+    friend class strided_array_view;
 
 public:
-	using Base::rank;
-	using typename Base::bounds_type;
-	using typename Base::size_type;
-	using typename Base::pointer;
-	using typename Base::value_type;
-	using typename Base::index_type;
-	using typename Base::iterator;
-	using typename Base::const_iterator;
-	using typename Base::reference;
-	
-	// from static array of size N
-	template<size_type N>
-	strided_array_view(value_type(&values)[N], bounds_type bounds) : Base(values, std::move(bounds))
-	{
-		fail_fast_assert(this->bounds().total_size() <= N, "Bounds cross data boundaries");
-	}
+    using Base::rank;
+    using typename Base::bounds_type;
+    using typename Base::size_type;
+    using typename Base::pointer;
+    using typename Base::value_type;
+    using typename Base::index_type;
+    using typename Base::iterator;
+    using typename Base::const_iterator;
+    using typename Base::reference;
+    
+    // from static array of size N
+    template<size_type N>
+    strided_array_view(value_type(&values)[N], bounds_type bounds) : Base(values, std::move(bounds))
+    {
+        fail_fast_assert(this->bounds().total_size() <= N, "Bounds cross data boundaries");
+    }
 
-	// from raw data
-	strided_array_view(pointer ptr, size_type size, bounds_type bounds): Base(ptr, std::move(bounds))
-	{
-		fail_fast_assert(this->bounds().total_size() <= size, "Bounds cross data boundaries");
-	}
+    // from raw data
+    strided_array_view(pointer ptr, size_type size, bounds_type bounds): Base(ptr, std::move(bounds))
+    {
+        fail_fast_assert(this->bounds().total_size() <= size, "Bounds cross data boundaries");
+    }
 
-	// from array view
-	template <std::ptrdiff_t... Dimensions, typename Dummy = std::enable_if<sizeof...(Dimensions) == Rank>>
-	strided_array_view(array_view<ValueType, Dimensions...> av, bounds_type bounds) : Base(av.data(), std::move(bounds))
-	{
-		fail_fast_assert(this->bounds().total_size() <= av.bounds().total_size(), "Bounds cross data boundaries");
-	}
-	
-	// convertible
-	template <typename OtherValueType,
-		typename BaseType = basic_array_view<ValueType, strided_bounds<Rank>>,
-		typename OtherBaseType = basic_array_view<OtherValueType, strided_bounds<Rank>>,
-		typename Dummy = std::enable_if_t<std::is_convertible<OtherBaseType, BaseType>::value>
-	>
+    // from array view
+    template <std::ptrdiff_t... Dimensions, typename Dummy = std::enable_if<sizeof...(Dimensions) == Rank>>
+    strided_array_view(array_view<ValueType, Dimensions...> av, bounds_type bounds) : Base(av.data(), std::move(bounds))
+    {
+        fail_fast_assert(this->bounds().total_size() <= av.bounds().total_size(), "Bounds cross data boundaries");
+    }
+    
+    // convertible
+    template <typename OtherValueType,
+        typename BaseType = basic_array_view<ValueType, strided_bounds<Rank>>,
+        typename OtherBaseType = basic_array_view<OtherValueType, strided_bounds<Rank>>,
+        typename Dummy = std::enable_if_t<std::is_convertible<OtherBaseType, BaseType>::value>
+    >
     constexpr strided_array_view(const strided_array_view<OtherValueType, Rank> &av) : Base(static_cast<const typename strided_array_view<OtherValueType, Rank>::Base &>(av)) // static_cast is required
     {}
 
-	// convert from bytes
-		template <typename OtherValueType>
-		strided_array_view<typename std::enable_if<std::is_same<value_type, const byte>::value, OtherValueType>::type, rank> as_strided_array_view() const 
-	{
-		static_assert((sizeof(OtherValueType) >= sizeof(value_type)) && (sizeof(OtherValueType) % sizeof(value_type) == 0), "OtherValueType should have a size to contain a multiple of ValueTypes");
-		auto d = static_cast<size_type>(sizeof(OtherValueType) / sizeof(value_type));
+    // convert from bytes
+        template <typename OtherValueType>
+        strided_array_view<typename std::enable_if<std::is_same<value_type, const byte>::value, OtherValueType>::type, rank> as_strided_array_view() const 
+    {
+        static_assert((sizeof(OtherValueType) >= sizeof(value_type)) && (sizeof(OtherValueType) % sizeof(value_type) == 0), "OtherValueType should have a size to contain a multiple of ValueTypes");
+        auto d = static_cast<size_type>(sizeof(OtherValueType) / sizeof(value_type));
 
-		size_type size = this->bounds().total_size() / d;
-		return{ (OtherValueType*)this->data(), size, bounds_type{ resize_extent(this->bounds().index_bounds(), d), resize_stride(this->bounds().strides(), d)} };
-	}
+        size_type size = this->bounds().total_size() / d;
+        return{ (OtherValueType*)this->data(), size, bounds_type{ resize_extent(this->bounds().index_bounds(), d), resize_stride(this->bounds().strides(), d)} };
+    }
 
-	strided_array_view section(index_type origin, index_type extents) const
-	{
-		size_type size = this->bounds().total_size() - this->bounds().linearize(origin);
-		return { &this->operator[](origin), size, bounds_type {extents, details::make_stride(Base::bounds())}};
-	}
+    strided_array_view section(index_type origin, index_type extents) const
+    {
+        size_type size = this->bounds().total_size() - this->bounds().linearize(origin);
+        return { &this->operator[](origin), size, bounds_type {extents, details::make_stride(Base::bounds())}};
+    }
 
-	constexpr reference operator[](const index_type& idx) const
-	{
-		return Base::operator[](idx);
-	}
+    constexpr reference operator[](const index_type& idx) const
+    {
+        return Base::operator[](idx);
+    }
 
-	template <bool Enabled = (rank > 1), typename Dummy = std::enable_if_t<Enabled>>
-	constexpr strided_array_view<value_type, rank-1> operator[](size_type idx) const
-	{
-		auto ret = Base::operator[](idx);
-		return{ ret.data(), ret.bounds().total_size(), ret.bounds() };
-	}
+    template <bool Enabled = (rank > 1), typename Dummy = std::enable_if_t<Enabled>>
+    constexpr strided_array_view<value_type, rank-1> operator[](size_type idx) const
+    {
+        auto ret = Base::operator[](idx);
+        return{ ret.data(), ret.bounds().total_size(), ret.bounds() };
+    }
 
 private:
-	static index_type resize_extent(const index_type& extent, std::ptrdiff_t d)
-	{
-		fail_fast_assert(extent[rank - 1] >= d && (extent[rank-1] % d == 0), "The last dimension of the array needs to contain a multiple of new type elements");
+    static index_type resize_extent(const index_type& extent, std::ptrdiff_t d)
+    {
+        fail_fast_assert(extent[rank - 1] >= d && (extent[rank-1] % d == 0), "The last dimension of the array needs to contain a multiple of new type elements");
 
-		index_type ret = extent;
-		ret[rank - 1] /= d;
+        index_type ret = extent;
+        ret[rank - 1] /= d;
 
-		return ret;
-	}
+        return ret;
+    }
 
-	template <bool Enabled = (rank == 1), typename Dummy = std::enable_if_t<Enabled>>
-	static index_type resize_stride(const index_type& strides, std::ptrdiff_t , void * = 0)
-	{
-		fail_fast_assert(strides[rank - 1] == 1, "Only strided arrays with regular strides can be resized");
+    template <bool Enabled = (rank == 1), typename Dummy = std::enable_if_t<Enabled>>
+    static index_type resize_stride(const index_type& strides, std::ptrdiff_t , void * = 0)
+    {
+        fail_fast_assert(strides[rank - 1] == 1, "Only strided arrays with regular strides can be resized");
 
-		return strides;
-	}
+        return strides;
+    }
 
-	template <bool Enabled = (rank > 1), typename Dummy = std::enable_if_t<Enabled>>
-	static index_type resize_stride(const index_type& strides, std::ptrdiff_t d)
-	{
-		fail_fast_assert(strides[rank - 1] == 1, "Only strided arrays with regular strides can be resized");
-		fail_fast_assert(strides[rank - 2] >= d && (strides[rank - 2] % d == 0), "The strides must have contiguous chunks of memory that can contain a multiple of new type elements");
+    template <bool Enabled = (rank > 1), typename Dummy = std::enable_if_t<Enabled>>
+    static index_type resize_stride(const index_type& strides, std::ptrdiff_t d)
+    {
+        fail_fast_assert(strides[rank - 1] == 1, "Only strided arrays with regular strides can be resized");
+        fail_fast_assert(strides[rank - 2] >= d && (strides[rank - 2] % d == 0), "The strides must have contiguous chunks of memory that can contain a multiple of new type elements");
 
-		for (size_t i = rank - 1; i > 0; --i)
-			fail_fast_assert((strides[i-1] >= strides[i]) && (strides[i-1] % strides[i] == 0), "Only strided arrays with regular strides can be resized");
+        for (size_t i = rank - 1; i > 0; --i)
+            fail_fast_assert((strides[i-1] >= strides[i]) && (strides[i-1] % strides[i] == 0), "Only strided arrays with regular strides can be resized");
 
-		index_type ret = strides / d;
-		ret[rank - 1] = 1;
+        index_type ret = strides / d;
+        ret[rank - 1] = 1;
 
-		return ret;
-	}
+        return ret;
+    }
 };
 
 template <typename ArrayView>
 class contiguous_array_view_iterator : public std::iterator<std::random_access_iterator_tag, typename ArrayView::value_type>
 {
-	using Base = std::iterator<std::random_access_iterator_tag, typename ArrayView::value_type>;
+    using Base = std::iterator<std::random_access_iterator_tag, typename ArrayView::value_type>;
 public:
-	using typename Base::reference;
-	using typename Base::pointer;
-	using typename Base::difference_type;
+    using typename Base::reference;
+    using typename Base::pointer;
+    using typename Base::difference_type;
 
 private:
-	template <typename ValueType, typename Bounds>
-	friend class basic_array_view;
+    template <typename ValueType, typename Bounds>
+    friend class basic_array_view;
 
     pointer m_pdata;
-	const ArrayView * m_validator;
-	void validateThis() const
-	{
-		fail_fast_assert(m_pdata >= m_validator->m_pdata && m_pdata < m_validator->m_pdata + m_validator->size(), "iterator is out of range of the array");
-	}
-	contiguous_array_view_iterator (const ArrayView *container, bool isbegin) :
-		m_pdata(isbegin ? container->m_pdata : container->m_pdata + container->size()), m_validator(container) {}
+    const ArrayView * m_validator;
+    void validateThis() const
+    {
+        fail_fast_assert(m_pdata >= m_validator->m_pdata && m_pdata < m_validator->m_pdata + m_validator->size(), "iterator is out of range of the array");
+    }
+    contiguous_array_view_iterator (const ArrayView *container, bool isbegin) :
+        m_pdata(isbegin ? container->m_pdata : container->m_pdata + container->size()), m_validator(container) {}
 public:
-	reference operator*() const noexcept
-	{
-		validateThis();
-		return *m_pdata;
-	}
-	pointer operator->() const noexcept
-	{
-		validateThis();
-		return m_pdata;
-	}
-	contiguous_array_view_iterator& operator++() noexcept
-	{
-		++m_pdata;
-		return *this;
-	}
-	contiguous_array_view_iterator operator++(int)noexcept
-	{
-		auto ret = *this;
-		++(*this);
-		return ret;
-	}
-	contiguous_array_view_iterator& operator--() noexcept
-	{
-		--m_pdata;
-		return *this;
-	}
-	contiguous_array_view_iterator operator--(int)noexcept
-	{
-		auto ret = *this;
-		--(*this);
-		return ret;
-	}
-	contiguous_array_view_iterator operator+(difference_type n) const noexcept
-	{
-		contiguous_array_view_iterator ret{ *this };
-		return ret += n;
-	}
-	contiguous_array_view_iterator& operator+=(difference_type n) noexcept
-	{
-		m_pdata += n;
-		return *this;
-	}
-	contiguous_array_view_iterator operator-(difference_type n) const noexcept
-	{
-		contiguous_array_view_iterator ret{ *this };
-		return ret -= n;
-	}
-	contiguous_array_view_iterator& operator-=(difference_type n) noexcept
-	{
-		return *this += -n;
-	}
-	difference_type operator-(const contiguous_array_view_iterator& rhs) const noexcept
-	{
-		fail_fast_assert(m_validator == rhs.m_validator);
-		return m_pdata - rhs.m_pdata;
-	}
-	reference operator[](difference_type n) const noexcept
-	{
-		return *(*this + n);
-	}
-	bool operator==(const contiguous_array_view_iterator& rhs) const noexcept
-	{
-		fail_fast_assert(m_validator == rhs.m_validator);
-		return m_pdata == rhs.m_pdata;
-	}
-	bool operator!=(const contiguous_array_view_iterator& rhs) const noexcept
-	{
-		return !(*this == rhs);
-	}
-	bool operator<(const contiguous_array_view_iterator& rhs) const noexcept
-	{
-		fail_fast_assert(m_validator == rhs.m_validator);
-		return m_pdata < rhs.m_pdata;
-	}
-	bool operator<=(const contiguous_array_view_iterator& rhs) const noexcept
-	{
-		return !(rhs < *this);
-	}
-	bool operator>(const contiguous_array_view_iterator& rhs) const noexcept
-	{
-		return rhs < *this;
-	}
-	bool operator>=(const contiguous_array_view_iterator& rhs) const noexcept
-	{
-		return !(rhs > *this);
-	}
-	void swap(contiguous_array_view_iterator& rhs) noexcept
-	{
-		std::swap(m_pdata, rhs.m_pdata);
-		std::swap(m_validator, rhs.m_validator);
-	}
+    reference operator*() const noexcept
+    {
+        validateThis();
+        return *m_pdata;
+    }
+    pointer operator->() const noexcept
+    {
+        validateThis();
+        return m_pdata;
+    }
+    contiguous_array_view_iterator& operator++() noexcept
+    {
+        ++m_pdata;
+        return *this;
+    }
+    contiguous_array_view_iterator operator++(int)noexcept
+    {
+        auto ret = *this;
+        ++(*this);
+        return ret;
+    }
+    contiguous_array_view_iterator& operator--() noexcept
+    {
+        --m_pdata;
+        return *this;
+    }
+    contiguous_array_view_iterator operator--(int)noexcept
+    {
+        auto ret = *this;
+        --(*this);
+        return ret;
+    }
+    contiguous_array_view_iterator operator+(difference_type n) const noexcept
+    {
+        contiguous_array_view_iterator ret{ *this };
+        return ret += n;
+    }
+    contiguous_array_view_iterator& operator+=(difference_type n) noexcept
+    {
+        m_pdata += n;
+        return *this;
+    }
+    contiguous_array_view_iterator operator-(difference_type n) const noexcept
+    {
+        contiguous_array_view_iterator ret{ *this };
+        return ret -= n;
+    }
+    contiguous_array_view_iterator& operator-=(difference_type n) noexcept
+    {
+        return *this += -n;
+    }
+    difference_type operator-(const contiguous_array_view_iterator& rhs) const noexcept
+    {
+        fail_fast_assert(m_validator == rhs.m_validator);
+        return m_pdata - rhs.m_pdata;
+    }
+    reference operator[](difference_type n) const noexcept
+    {
+        return *(*this + n);
+    }
+    bool operator==(const contiguous_array_view_iterator& rhs) const noexcept
+    {
+        fail_fast_assert(m_validator == rhs.m_validator);
+        return m_pdata == rhs.m_pdata;
+    }
+    bool operator!=(const contiguous_array_view_iterator& rhs) const noexcept
+    {
+        return !(*this == rhs);
+    }
+    bool operator<(const contiguous_array_view_iterator& rhs) const noexcept
+    {
+        fail_fast_assert(m_validator == rhs.m_validator);
+        return m_pdata < rhs.m_pdata;
+    }
+    bool operator<=(const contiguous_array_view_iterator& rhs) const noexcept
+    {
+        return !(rhs < *this);
+    }
+    bool operator>(const contiguous_array_view_iterator& rhs) const noexcept
+    {
+        return rhs < *this;
+    }
+    bool operator>=(const contiguous_array_view_iterator& rhs) const noexcept
+    {
+        return !(rhs > *this);
+    }
+    void swap(contiguous_array_view_iterator& rhs) noexcept
+    {
+        std::swap(m_pdata, rhs.m_pdata);
+        std::swap(m_validator, rhs.m_validator);
+    }
 };
 
 template <typename ArrayView>
 contiguous_array_view_iterator<ArrayView> operator+(typename contiguous_array_view_iterator<ArrayView>::difference_type n, const contiguous_array_view_iterator<ArrayView>& rhs) noexcept
 {
-	return rhs + n;
+    return rhs + n;
 }
 
 template <typename ArrayView>
 class general_array_view_iterator : public std::iterator<std::random_access_iterator_tag, typename ArrayView::value_type>
 {
-	using Base = std::iterator<std::random_access_iterator_tag, typename ArrayView::value_type>;
+    using Base = std::iterator<std::random_access_iterator_tag, typename ArrayView::value_type>;
 public:
-	using typename Base::reference;
-	using typename Base::pointer;
-	using typename Base::difference_type;
-	using typename Base::value_type;
+    using typename Base::reference;
+    using typename Base::pointer;
+    using typename Base::difference_type;
+    using typename Base::value_type;
 private:
-	template <typename ValueType, typename Bounds>
-	friend class basic_array_view;
-	
+    template <typename ValueType, typename Bounds>
+    friend class basic_array_view;
+    
     const ArrayView * m_container;
-	typename ArrayView::bounds_type::iterator m_itr;
-	general_array_view_iterator(const ArrayView *container, bool isbegin) :
-		m_container(container), m_itr(isbegin ? m_container->bounds().begin() : m_container->bounds().end())
-	{}
+    typename ArrayView::bounds_type::iterator m_itr;
+    general_array_view_iterator(const ArrayView *container, bool isbegin) :
+        m_container(container), m_itr(isbegin ? m_container->bounds().begin() : m_container->bounds().end())
+    {}
 public:
-	reference operator*() noexcept
-	{
-		return (*m_container)[*m_itr];
-	}
-	pointer operator->() noexcept
-	{
-		return &(*m_container)[*m_itr];
-	}
-	general_array_view_iterator& operator++() noexcept
-	{
-		++m_itr;
-		return *this;
-	}
-	general_array_view_iterator operator++(int)noexcept
-	{
-		auto ret = *this;
-		++(*this);
-		return ret;
-	}
-	general_array_view_iterator& operator--() noexcept
-	{
-		--m_itr;
-		return *this;
-	}
-	general_array_view_iterator operator--(int)noexcept
-	{
-		auto ret = *this;
-		--(*this);
-		return ret;
-	}
-	general_array_view_iterator operator+(difference_type n) const noexcept
-	{
-		general_array_view_iterator ret{ *this };
-		return ret += n;
-	}
-	general_array_view_iterator& operator+=(difference_type n) noexcept
-	{
-		m_itr += n;
-		return *this;
-	}
-	general_array_view_iterator operator-(difference_type n) const noexcept
-	{
-		general_array_view_iterator ret{ *this };
-		return ret -= n;
-	}
-	general_array_view_iterator& operator-=(difference_type n) noexcept
-	{
-		return *this += -n;
-	}
-	difference_type operator-(const general_array_view_iterator& rhs) const noexcept
-	{
-		fail_fast_assert(m_container == rhs.m_container);
-		return m_itr - rhs.m_itr;
-	}
-	value_type operator[](difference_type n) const noexcept
-	{
-		return (*m_container)[m_itr[n]];;
-	}
-	bool operator==(const general_array_view_iterator& rhs) const noexcept
-	{
-		fail_fast_assert(m_container == rhs.m_container);
-		return m_itr == rhs.m_itr;
-	}
-	bool operator !=(const general_array_view_iterator& rhs) const noexcept
-	{
-		return !(*this == rhs);
-	}
-	bool operator<(const general_array_view_iterator& rhs) const noexcept
-	{
-		fail_fast_assert(m_container == rhs.m_container);
-		return m_itr < rhs.m_itr;
-	}
-	bool operator<=(const general_array_view_iterator& rhs) const noexcept
-	{
-		return !(rhs < *this);
-	}
-	bool operator>(const general_array_view_iterator& rhs) const noexcept
-	{
-		return rhs < *this;
-	}
-	bool operator>=(const general_array_view_iterator& rhs) const noexcept
-	{
-		return !(rhs > *this);
-	}
-	void swap(general_array_view_iterator& rhs) noexcept
-	{
-		std::swap(m_itr, rhs.m_itr);
-		std::swap(m_container, rhs.m_container);
-	}
+    reference operator*() noexcept
+    {
+        return (*m_container)[*m_itr];
+    }
+    pointer operator->() noexcept
+    {
+        return &(*m_container)[*m_itr];
+    }
+    general_array_view_iterator& operator++() noexcept
+    {
+        ++m_itr;
+        return *this;
+    }
+    general_array_view_iterator operator++(int)noexcept
+    {
+        auto ret = *this;
+        ++(*this);
+        return ret;
+    }
+    general_array_view_iterator& operator--() noexcept
+    {
+        --m_itr;
+        return *this;
+    }
+    general_array_view_iterator operator--(int)noexcept
+    {
+        auto ret = *this;
+        --(*this);
+        return ret;
+    }
+    general_array_view_iterator operator+(difference_type n) const noexcept
+    {
+        general_array_view_iterator ret{ *this };
+        return ret += n;
+    }
+    general_array_view_iterator& operator+=(difference_type n) noexcept
+    {
+        m_itr += n;
+        return *this;
+    }
+    general_array_view_iterator operator-(difference_type n) const noexcept
+    {
+        general_array_view_iterator ret{ *this };
+        return ret -= n;
+    }
+    general_array_view_iterator& operator-=(difference_type n) noexcept
+    {
+        return *this += -n;
+    }
+    difference_type operator-(const general_array_view_iterator& rhs) const noexcept
+    {
+        fail_fast_assert(m_container == rhs.m_container);
+        return m_itr - rhs.m_itr;
+    }
+    value_type operator[](difference_type n) const noexcept
+    {
+        return (*m_container)[m_itr[n]];;
+    }
+    bool operator==(const general_array_view_iterator& rhs) const noexcept
+    {
+        fail_fast_assert(m_container == rhs.m_container);
+        return m_itr == rhs.m_itr;
+    }
+    bool operator !=(const general_array_view_iterator& rhs) const noexcept
+    {
+        return !(*this == rhs);
+    }
+    bool operator<(const general_array_view_iterator& rhs) const noexcept
+    {
+        fail_fast_assert(m_container == rhs.m_container);
+        return m_itr < rhs.m_itr;
+    }
+    bool operator<=(const general_array_view_iterator& rhs) const noexcept
+    {
+        return !(rhs < *this);
+    }
+    bool operator>(const general_array_view_iterator& rhs) const noexcept
+    {
+        return rhs < *this;
+    }
+    bool operator>=(const general_array_view_iterator& rhs) const noexcept
+    {
+        return !(rhs > *this);
+    }
+    void swap(general_array_view_iterator& rhs) noexcept
+    {
+        std::swap(m_itr, rhs.m_itr);
+        std::swap(m_container, rhs.m_container);
+    }
 };
 
 template <typename ArrayView>
 general_array_view_iterator<ArrayView> operator+(typename general_array_view_iterator<ArrayView>::difference_type n, const general_array_view_iterator<ArrayView>& rhs) noexcept
 {
-	return rhs + n;
+    return rhs + n;
 }
 
 } // namespace gsl

From dbf0d5017c43beacd3ef885b6ea45b233e3690e5 Mon Sep 17 00:00:00 2001
From: Neil MacIntosh <neilmac@microsoft.com>
Date: Wed, 4 Nov 2015 12:17:41 -0800
Subject: [PATCH 07/43] Reactivated tests disabled during development.

---
 tests/array_view_tests.cpp | 138 ++++++++++++++++++-------------------
 1 file changed, 69 insertions(+), 69 deletions(-)

diff --git a/tests/array_view_tests.cpp b/tests/array_view_tests.cpp
index d9d0a42..dd2067f 100644
--- a/tests/array_view_tests.cpp
+++ b/tests/array_view_tests.cpp
@@ -241,11 +241,11 @@ SUITE(array_view_tests)
 		
 		auto av8 = av7.as_array_view<int>();
 
-		//CHECK(av8.size() == av6.size());
-		//for (auto i = 0; i < av8.size(); i++)
-		//{
-		//	CHECK(av8[i] == 1);
-		//}
+		CHECK(av8.size() == av6.size());
+		for (auto i = 0; i < av8.size(); i++)
+		{
+			CHECK(av8[i] == 1);
+		}
 
 #ifdef CONFIRM_COMPILATION_ERRORS
 		struct Foo {char c[11];};
@@ -404,71 +404,71 @@ SUITE(array_view_tests)
 			array_view<const int, 2> av2{ av };
 			CHECK(av2[1] == 5);
 
-		//	static_assert(std::is_convertible<const array_view<int, 2>, array_view<const int, 2>>::value, "ctor is not implicit!");
-		//
-		//	const strided_array_view<int, 1> src{ arr, {2, 1} };
-		//	strided_array_view<const int, 1> sav{ src };
-		//	CHECK(sav.bounds().index_bounds() == index<1>{ 2 });
-		//	CHECK(sav.bounds().stride() == 1);
-		//	CHECK(sav[1] == 5);
-		//	
-		//	static_assert(std::is_convertible<const strided_array_view<int, 1>, strided_array_view<const int, 1>>::value, "ctor is not implicit!");
+			static_assert(std::is_convertible<const array_view<int, 2>, array_view<const int, 2>>::value, "ctor is not implicit!");
+		
+			const strided_array_view<int, 1> src{ arr, {2, 1} };
+			strided_array_view<const int, 1> sav{ src };
+			CHECK(sav.bounds().index_bounds() == index<1>{ 2 });
+			CHECK(sav.bounds().stride() == 1);
+			CHECK(sav[1] == 5);
+			
+			static_assert(std::is_convertible<const strided_array_view<int, 1>, strided_array_view<const int, 1>>::value, "ctor is not implicit!");
+		}
+
+		// Check copy constructor
+		{
+			int arr1[2] = { 3, 4 };
+			const strided_array_view<int, 1> src1{ arr1, {2, 1} };
+			strided_array_view<int, 1> sav1{ src1 };
+ 
+			CHECK(sav1.bounds().index_bounds() == index<1>{ 2 });
+			CHECK(sav1.bounds().stride() == 1);
+			CHECK(sav1[0] == 3);
+
+			int arr2[6] = { 1, 2, 3, 4, 5, 6 };
+			const strided_array_view<const int, 2> src2{ arr2, {{ 3, 2 }, { 2, 1 }} };
+			strided_array_view<const int, 2> sav2{ src2 };
+			CHECK((sav2.bounds().index_bounds() == index<2>{ 3, 2 }));
+			CHECK((sav2.bounds().strides() == index<2>{ 2, 1 }));
+			CHECK((sav2[{0, 0}] == 1 && sav2[{2, 0}] == 5));
+		}
+
+		// Check const-casting assignment operator
+		{
+			int arr1[2] = { 1, 2 };
+			int arr2[6] = { 3, 4, 5, 6, 7, 8 };
+
+			const strided_array_view<int, 1> src{ arr1, {{2}, {1}} };
+			strided_array_view<const int, 1> sav{ arr2, {{3}, {2}} };
+			strided_array_view<const int, 1>& sav_ref = (sav = src);
+			CHECK(sav.bounds().index_bounds() == index<1>{ 2 });
+			CHECK(sav.bounds().strides() == index<1>{ 1 });
+			CHECK(sav[0] == 1);
+			CHECK(&sav_ref == &sav);
+		}
+		
+		// Check copy assignment operator
+		{
+			int arr1[2] = { 3, 4 };
+			int arr1b[1] = { 0 };
+			const strided_array_view<int, 1> src1{ arr1, {2, 1} };
+			strided_array_view<int, 1> sav1{ arr1b, {1, 1} };
+			strided_array_view<int, 1>& sav1_ref = (sav1 = src1);
+			CHECK(sav1.bounds().index_bounds() == index<1>{ 2 });
+			CHECK(sav1.bounds().strides() == index<1>{ 1 });
+			CHECK(sav1[0] == 3);
+			CHECK(&sav1_ref == &sav1);
+
+			const int arr2[6] = { 1, 2, 3, 4, 5, 6 };
+			const int arr2b[1] = { 0 };
+			const strided_array_view<const int, 2> src2{ arr2, {{ 3, 2 },{ 2, 1 }} };
+			strided_array_view<const int, 2> sav2{ arr2b, {{ 1, 1 },{ 1, 1 }} };
+			strided_array_view<const int, 2>& sav2_ref = (sav2 = src2);
+			CHECK((sav2.bounds().index_bounds() == index<2>{ 3, 2 }));
+			CHECK((sav2.bounds().strides() == index<2>{ 2, 1 }));
+			CHECK((sav2[{0, 0}] == 1 && sav2[{2, 0}] == 5));
+			CHECK(&sav2_ref == &sav2);
 		}
-//
-//		// Check copy constructor
-//		{
-//			int arr1[2] = { 3, 4 };
-//			const strided_array_view<int, 1> src1{ arr1, {2, 1} };
-//			strided_array_view<int, 1> sav1{ src1 };
-// 
-//			CHECK(sav1.bounds().index_bounds() == index<1>{ 2 });
-//			CHECK(sav1.bounds().stride() == 1);
-//			CHECK(sav1[0] == 3);
-//
-//			int arr2[6] = { 1, 2, 3, 4, 5, 6 };
-//			const strided_array_view<const int, 2> src2{ arr2, {{ 3, 2 }, { 2, 1 }} };
-//			strided_array_view<const int, 2> sav2{ src2 };
-//			CHECK((sav2.bounds().index_bounds() == index<2>{ 3, 2 }));
-//			CHECK((sav2.bounds().strides() == index<2>{ 2, 1 }));
-//			CHECK((sav2[{0, 0}] == 1 && sav2[{2, 0}] == 5));
-//		}
-//
-//		// Check const-casting assignment operator
-//		{
-//			int arr1[2] = { 1, 2 };
-//			int arr2[6] = { 3, 4, 5, 6, 7, 8 };
-//
-//			const strided_array_view<int, 1> src{ arr1, {{2}, {1}} };
-//			strided_array_view<const int, 1> sav{ arr2, {{3}, {2}} };
-//			strided_array_view<const int, 1>& sav_ref = (sav = src);
-//			CHECK(sav.bounds().index_bounds() == index<1>{ 2 });
-//			CHECK(sav.bounds().strides() == index<1>{ 1 });
-//			CHECK(sav[0] == 1);
-//			CHECK(&sav_ref == &sav);
-//		}
-//		
-//		// Check copy assignment operator
-//		{
-//			int arr1[2] = { 3, 4 };
-//			int arr1b[1] = { 0 };
-//			const strided_array_view<int, 1> src1{ arr1, {2, 1} };
-//			strided_array_view<int, 1> sav1{ arr1b, {1, 1} };
-//			strided_array_view<int, 1>& sav1_ref = (sav1 = src1);
-//			CHECK(sav1.bounds().index_bounds() == index<1>{ 2 });
-//			CHECK(sav1.bounds().strides() == index<1>{ 1 });
-//			CHECK(sav1[0] == 3);
-//			CHECK(&sav1_ref == &sav1);
-//
-//			const int arr2[6] = { 1, 2, 3, 4, 5, 6 };
-//			const int arr2b[1] = { 0 };
-//			const strided_array_view<const int, 2> src2{ arr2, {{ 3, 2 },{ 2, 1 }} };
-//			strided_array_view<const int, 2> sav2{ arr2b, {{ 1, 1 },{ 1, 1 }} };
-//			strided_array_view<const int, 2>& sav2_ref = (sav2 = src2);
-//			CHECK((sav2.bounds().index_bounds() == index<2>{ 3, 2 }));
-//			CHECK((sav2.bounds().strides() == index<2>{ 2, 1 }));
-//			CHECK((sav2[{0, 0}] == 1 && sav2[{2, 0}] == 5));
-//			CHECK(&sav2_ref == &sav2);
-//		}
 	}
 
 	TEST(strided_array_view_slice)

From b63ec949e99963e17f96f131ae5458c437b014bc Mon Sep 17 00:00:00 2001
From: Neil MacIntosh <neilmac@microsoft.com>
Date: Wed, 4 Nov 2015 12:42:27 -0800
Subject: [PATCH 08/43] Renaming array_view and string_view, as per WG21
 discussions.

---
 include/gsl.h                                 |   4 +-
 include/{array_view.h => span.h}              | 290 ++++-----
 include/{string_view.h => string_span.h}      |  59 +-
 tests/CMakeLists.txt                          |   4 +-
 tests/bounds_tests.cpp                        |   4 +-
 .../{array_view_tests.cpp => span_tests.cpp}  | 600 +++++++++---------
 ...g_view_tests.cpp => string_span_tests.cpp} |  32 +-
 7 files changed, 495 insertions(+), 498 deletions(-)
 rename include/{array_view.h => span.h} (82%)
 rename include/{string_view.h => string_span.h} (71%)
 rename tests/{array_view_tests.cpp => span_tests.cpp} (63%)
 rename tests/{string_view_tests.cpp => string_span_tests.cpp} (78%)

diff --git a/include/gsl.h b/include/gsl.h
index ec75723..e20ac69 100644
--- a/include/gsl.h
+++ b/include/gsl.h
@@ -19,8 +19,8 @@
 #ifndef GSL_GSL_H
 #define GSL_GSL_H
 
-#include "array_view.h"     // array_view, strided_array_view...
-#include "string_view.h"    // zstring, string_view, zstring_builder...
+#include "span.h"           // span, strided_span...
+#include "string_span.h"    // zstring, string_span, zstring_builder...
 #include <memory>
 
 #ifdef _MSC_VER
diff --git a/include/array_view.h b/include/span.h
similarity index 82%
rename from include/array_view.h
rename to include/span.h
index cbc33be..74da1aa 100644
--- a/include/array_view.h
+++ b/include/span.h
@@ -16,8 +16,8 @@
 
 #pragma once
 
-#ifndef GSL_ARRAY_VIEW_H
-#define GSL_ARRAY_VIEW_H
+#ifndef GSL_SPAN_H
+#define GSL_SPAN_H
 
 #include <new>
 #include <stdexcept>
@@ -998,7 +998,7 @@ bounds_iterator<IndexType> operator+(typename bounds_iterator<IndexType>::differ
 }
 
 //
-// begin definitions of basic_array_view
+// begin definitions of basic_span
 //
 namespace details
 {
@@ -1036,13 +1036,13 @@ namespace details
 } // namespace details
 
 template <typename ArrayView>
-class contiguous_array_view_iterator;
+class contiguous_span_iterator;
 template <typename ArrayView>
-class general_array_view_iterator;
+class general_span_iterator;
 enum class byte : std::uint8_t {};
 
 template <typename ValueType, typename BoundsType>
-class basic_array_view
+class basic_span
 {
 public:
     static const size_t rank = BoundsType::rank;
@@ -1053,11 +1053,11 @@ public:
     using const_value_type = std::add_const_t<value_type>;
     using pointer = ValueType*;
     using reference = ValueType&;
-    using iterator = std::conditional_t<std::is_same<typename BoundsType::mapping_type, contiguous_mapping_tag>::value, contiguous_array_view_iterator<basic_array_view>, general_array_view_iterator<basic_array_view>>;
-    using const_iterator = std::conditional_t<std::is_same<typename BoundsType::mapping_type, contiguous_mapping_tag>::value, contiguous_array_view_iterator<basic_array_view<const_value_type, BoundsType>>, general_array_view_iterator<basic_array_view<const_value_type, BoundsType>>>;
+    using iterator = std::conditional_t<std::is_same<typename BoundsType::mapping_type, contiguous_mapping_tag>::value, contiguous_span_iterator<basic_span>, general_span_iterator<basic_span>>;
+    using const_iterator = std::conditional_t<std::is_same<typename BoundsType::mapping_type, contiguous_mapping_tag>::value, contiguous_span_iterator<basic_span<const_value_type, BoundsType>>, general_span_iterator<basic_span<const_value_type, BoundsType>>>;
     using reverse_iterator = std::reverse_iterator<iterator>;
     using const_reverse_iterator = std::reverse_iterator<const_iterator>;
-    using sliced_type = std::conditional_t<rank == 1, value_type, basic_array_view<value_type, typename BoundsType::sliced_type>>;
+    using sliced_type = std::conditional_t<rank == 1, value_type, basic_span<value_type, typename BoundsType::sliced_type>>;
 
 private:
     pointer m_pdata;
@@ -1111,11 +1111,11 @@ public:
     }
     constexpr const_iterator cbegin() const
     {
-        return const_iterator {reinterpret_cast<const basic_array_view<const value_type, bounds_type> *>(this), true};
+        return const_iterator {reinterpret_cast<const basic_span<const value_type, bounds_type> *>(this), true};
     }
     constexpr const_iterator cend() const
     {
-        return const_iterator {reinterpret_cast<const basic_array_view<const value_type, bounds_type> *>(this), false};
+        return const_iterator {reinterpret_cast<const basic_span<const value_type, bounds_type> *>(this), false};
     }
 
     constexpr reverse_iterator rbegin() const
@@ -1136,38 +1136,38 @@ public:
     }
 
     template <typename OtherValueType, typename OtherBoundsType, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
-    constexpr bool operator== (const basic_array_view<OtherValueType, OtherBoundsType> & other) const noexcept
+    constexpr bool operator== (const basic_span<OtherValueType, OtherBoundsType> & other) const noexcept
     {
         return m_bounds.size() == other.m_bounds.size() &&
             (m_pdata == other.m_pdata || std::equal(this->begin(), this->end(), other.begin()));
     }
 
     template <typename OtherValueType, typename OtherBoundsType, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
-    constexpr bool operator!= (const basic_array_view<OtherValueType, OtherBoundsType> & other) const noexcept
+    constexpr bool operator!= (const basic_span<OtherValueType, OtherBoundsType> & other) const noexcept
     {
         return !(*this == other);
     }
 
     template <typename OtherValueType, typename OtherBoundsType, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
-    constexpr bool operator< (const basic_array_view<OtherValueType, OtherBoundsType> & other) const noexcept
+    constexpr bool operator< (const basic_span<OtherValueType, OtherBoundsType> & other) const noexcept
     {
         return std::lexicographical_compare(this->begin(), this->end(), other.begin(), other.end());
     }
 
     template <typename OtherValueType, typename OtherBoundsType, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
-    constexpr bool operator<= (const basic_array_view<OtherValueType, OtherBoundsType> & other) const noexcept
+    constexpr bool operator<= (const basic_span<OtherValueType, OtherBoundsType> & other) const noexcept
     {
         return !(other < *this);
     }
 
     template <typename OtherValueType, typename OtherBoundsType, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
-    constexpr bool operator> (const basic_array_view<OtherValueType, OtherBoundsType> & other) const noexcept
+    constexpr bool operator> (const basic_span<OtherValueType, OtherBoundsType> & other) const noexcept
     {
         return (other < *this);
     }
 
     template <typename OtherValueType, typename OtherBoundsType, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
-    constexpr bool operator>= (const basic_array_view<OtherValueType, OtherBoundsType> & other) const noexcept
+    constexpr bool operator>= (const basic_span<OtherValueType, OtherBoundsType> & other) const noexcept
     {
         return !(*this < other);
     }
@@ -1176,27 +1176,27 @@ public:
     template <typename OtherValueType, typename OtherBounds,
         typename Dummy = std::enable_if_t<std::is_convertible<OtherValueType(*)[], value_type(*)[]>::value
             && std::is_convertible<OtherBounds, bounds_type>::value>>
-    constexpr basic_array_view(const basic_array_view<OtherValueType, OtherBounds> & other ) noexcept
+    constexpr basic_span(const basic_span<OtherValueType, OtherBounds> & other ) noexcept
         : m_pdata(other.m_pdata), m_bounds(other.m_bounds)
     {
     }
 protected:
 
-    constexpr basic_array_view(pointer data, bounds_type bound) noexcept
+    constexpr basic_span(pointer data, bounds_type bound) noexcept
         : m_pdata(data)
         , m_bounds(std::move(bound))
     {
         fail_fast_assert((m_bounds.size() > 0 && data != nullptr) || m_bounds.size() == 0);
     }
     template <typename T>
-    constexpr basic_array_view(T *data, std::enable_if_t<std::is_same<value_type, std::remove_all_extents_t<T>>::value, bounds_type> bound) noexcept
+    constexpr basic_span(T *data, std::enable_if_t<std::is_same<value_type, std::remove_all_extents_t<T>>::value, bounds_type> bound) noexcept
         : m_pdata(reinterpret_cast<pointer>(data))
         , m_bounds(std::move(bound))
     {
         fail_fast_assert((m_bounds.size() > 0 && data != nullptr) || m_bounds.size() == 0);
     }
     template <typename DestBounds>
-    constexpr basic_array_view<value_type, DestBounds> as_array_view(const DestBounds &bounds)
+    constexpr basic_span<value_type, DestBounds> as_span(const DestBounds &bounds)
     {
         details::verifyBoundsReshape(m_bounds, bounds);
         return {m_pdata, bounds};
@@ -1206,7 +1206,7 @@ private:
     friend iterator;
     friend const_iterator;
     template <typename ValueType2, typename BoundsType2>
-    friend class basic_array_view;
+    friend class basic_span;
 };
 
 template <std::ptrdiff_t DimSize = dynamic_range>
@@ -1223,10 +1223,10 @@ struct dim<dynamic_range>
 };
 
 template <typename ValueType, std::ptrdiff_t FirstDimension = dynamic_range, std::ptrdiff_t... RestDimensions>
-class array_view;
+class span;
 
 template <typename ValueType, size_t Rank>
-class strided_array_view;
+class strided_span;
 
 namespace details
 {
@@ -1238,15 +1238,15 @@ namespace details
     };
 
     template <typename Traits>
-    struct ArrayViewTypeTraits<Traits, typename std::is_reference<typename Traits::array_view_traits &>::type>
+    struct ArrayViewTypeTraits<Traits, typename std::is_reference<typename Traits::span_traits &>::type>
     {
-        using value_type = typename Traits::array_view_traits::value_type;
-        using size_type = typename Traits::array_view_traits::size_type;
+        using value_type = typename Traits::span_traits::value_type;
+        using size_type = typename Traits::span_traits::size_type;
     };
 
     template <typename T, std::ptrdiff_t... Ranks>
     struct ArrayViewArrayTraits {
-        using type = array_view<T, Ranks...>;
+        using type = span<T, Ranks...>;
         using value_type = T;
         using bounds_type = static_bounds<Ranks...>;
         using pointer = T*;
@@ -1277,54 +1277,54 @@ namespace details
     struct Sep{};
     
     template <typename T, typename... Args>
-    T static_as_array_view_helper(Sep, Args... args)
+    T static_as_span_helper(Sep, Args... args)
     {
         return T{static_cast<typename T::size_type>(args)...};
     }
     template <typename T, typename Arg, typename... Args>
-    std::enable_if_t<!std::is_same<Arg, dim<dynamic_range>>::value && !std::is_same<Arg, Sep>::value, T> static_as_array_view_helper(Arg, Args... args)
+    std::enable_if_t<!std::is_same<Arg, dim<dynamic_range>>::value && !std::is_same<Arg, Sep>::value, T> static_as_span_helper(Arg, Args... args)
     {
-        return static_as_array_view_helper<T>(args...);
+        return static_as_span_helper<T>(args...);
     }
     template <typename T, typename... Args>
-    T static_as_array_view_helper(dim<dynamic_range> val, Args ... args)
+    T static_as_span_helper(dim<dynamic_range> val, Args ... args)
     {
-        return static_as_array_view_helper<T>(args..., val.dvalue);
+        return static_as_span_helper<T>(args..., val.dvalue);
     }
 
     template <typename ...Dimensions>
-    struct static_as_array_view_static_bounds_helper
+    struct static_as_span_static_bounds_helper
     {
         using type = static_bounds<(Dimensions::value)...>;
     };
 
     template <typename T>
-    struct is_array_view_oracle : std::false_type
+    struct is_span_oracle : std::false_type
     {};
 
     template <typename ValueType, std::ptrdiff_t FirstDimension, std::ptrdiff_t... RestDimensions>
-    struct is_array_view_oracle<array_view<ValueType, FirstDimension, RestDimensions...>> : std::true_type
+    struct is_span_oracle<span<ValueType, FirstDimension, RestDimensions...>> : std::true_type
     {};
     
     template <typename ValueType, std::ptrdiff_t Rank>
-    struct is_array_view_oracle<strided_array_view<ValueType, Rank>> : std::true_type
+    struct is_span_oracle<strided_span<ValueType, Rank>> : std::true_type
     {};
     
     template <typename T>
-    struct is_array_view : is_array_view_oracle<std::remove_cv_t<T>>
+    struct is_span : is_span_oracle<std::remove_cv_t<T>>
     {};
 
 }
 
 
 template <typename ValueType, std::ptrdiff_t FirstDimension, std::ptrdiff_t... RestDimensions>
-class array_view : public basic_array_view <ValueType, static_bounds <FirstDimension, RestDimensions...>>
+class span : public basic_span <ValueType, static_bounds <FirstDimension, RestDimensions...>>
 {
     template <typename ValueType2, std::ptrdiff_t FirstDimension2,
               std::ptrdiff_t... RestDimensions2>
-    friend class array_view;
+    friend class span;
 
-    using Base = basic_array_view<ValueType, static_bounds<FirstDimension, RestDimensions...>>;
+    using Base = basic_span<ValueType, static_bounds<FirstDimension, RestDimensions...>>;
 
 public:
     using typename Base::bounds_type;
@@ -1339,42 +1339,42 @@ public:
 
 public:
     // basic
-    constexpr array_view(pointer ptr, size_type size) : Base(ptr, bounds_type{ size })
+    constexpr span(pointer ptr, size_type size) : Base(ptr, bounds_type{ size })
     {}
 
-    constexpr array_view(pointer ptr, bounds_type bounds) : Base(ptr, std::move(bounds))
+    constexpr span(pointer ptr, bounds_type bounds) : Base(ptr, std::move(bounds))
     {}
 
-    constexpr array_view(std::nullptr_t) : Base(nullptr, bounds_type{})
+    constexpr span(std::nullptr_t) : Base(nullptr, bounds_type{})
     {}
 
-    constexpr array_view(std::nullptr_t, size_type size) : Base(nullptr, bounds_type{})
+    constexpr span(std::nullptr_t, size_type size) : Base(nullptr, bounds_type{})
     {
         fail_fast_assert(size == 0);
     }
 
     // default
     template <std::ptrdiff_t DynamicRank = bounds_type::dynamic_rank, typename = std::enable_if_t<DynamicRank != 0>>
-    constexpr array_view() : Base(nullptr, bounds_type())
+    constexpr span() : Base(nullptr, bounds_type())
     {}
 
     // from n-dimensions dynamic array (e.g. new int[m][4]) (precedence will be lower than the 1-dimension pointer)
     template <typename T, typename Helper = details::ArrayViewArrayTraits<T, dynamic_range>
         /*typename Dummy = std::enable_if_t<std::is_convertible<Helper::value_type (*)[], typename Base::value_type (*)[]>::value>*/>
-    constexpr array_view(T* const& data, size_type size) : Base(data, typename Helper::bounds_type{size})
+    constexpr span(T* const& data, size_type size) : Base(data, typename Helper::bounds_type{size})
     {}
 
     // from n-dimensions static array
     template <typename T, size_t N, typename Helper = details::ArrayViewArrayTraits<T, N>,
         typename = std::enable_if_t<std::is_convertible<typename Helper::value_type(*)[], typename Base::value_type(*)[]>::value>>
-    constexpr array_view (T (&arr)[N]) : Base(arr, typename Helper::bounds_type())
+    constexpr span (T (&arr)[N]) : Base(arr, typename Helper::bounds_type())
     {}
 
     // from n-dimensions static array with size
     template <typename T, size_t N, typename Helper = details::ArrayViewArrayTraits<T, N>,
         typename = std::enable_if_t<std::is_convertible<typename Helper::value_type(*)[], typename Base::value_type(*)[]>::value>
     >
-    constexpr array_view(T(&arr)[N], size_type size) : Base(arr, typename Helper::bounds_type{size})
+    constexpr span(T(&arr)[N], size_type size) : Base(arr, typename Helper::bounds_type{size})
     {
         fail_fast_assert(size <= N);
     }
@@ -1383,14 +1383,14 @@ public:
     template <size_t N, 
        typename Dummy = std::enable_if_t<std::is_convertible<static_bounds<N>, typename Base::bounds_type>::value>
     >
-    constexpr array_view (std::array<std::remove_const_t<value_type>, N> & arr) : Base(arr.data(), static_bounds<N>())
+    constexpr span (std::array<std::remove_const_t<value_type>, N> & arr) : Base(arr.data(), static_bounds<N>())
     {}
 
     template <size_t N,
         typename Dummy = std::enable_if_t<std::is_convertible<static_bounds<N>, typename Base::bounds_type>::value
         && std::is_const<value_type>::value>
     >
-    constexpr array_view (const std::array<std::remove_const_t<value_type>, N> & arr) : Base(arr.data(), static_bounds<N>())
+    constexpr span (const std::array<std::remove_const_t<value_type>, N> & arr) : Base(arr.data(), static_bounds<N>())
     {}
     
     // from begin, end pointers. We don't provide iterator pair since no way to guarantee the contiguity 
@@ -1398,59 +1398,59 @@ public:
         typename Dummy = std::enable_if_t<std::is_convertible<Ptr, pointer>::value
         && details::LessThan<Base::bounds_type::dynamic_rank, 2>::value>
     > // remove literal 0 case
-    constexpr array_view (pointer begin, Ptr end) : Base(begin, details::newBoundsHelper<typename Base::bounds_type>(static_cast<pointer>(end) - begin))
+    constexpr span (pointer begin, Ptr end) : Base(begin, details::newBoundsHelper<typename Base::bounds_type>(static_cast<pointer>(end) - begin))
     {}
 
     // from containers. It must has .size() and .data() two function signatures
     template <typename Cont, typename DataType = typename Cont::value_type,
-        typename Dummy = std::enable_if_t<!details::is_array_view<Cont>::value
+        typename Dummy = std::enable_if_t<!details::is_span<Cont>::value
         && std::is_convertible<DataType (*)[], typename Base::value_type (*)[]>::value
         && std::is_same<std::decay_t<decltype(std::declval<Cont>().size(), *std::declval<Cont>().data())>, DataType>::value>
     >
-    constexpr array_view (Cont& cont) : Base(static_cast<pointer>(cont.data()), details::newBoundsHelper<typename Base::bounds_type>(cont.size()))
+    constexpr span (Cont& cont) : Base(static_cast<pointer>(cont.data()), details::newBoundsHelper<typename Base::bounds_type>(cont.size()))
     {}
 
-    constexpr array_view(const array_view &) = default;
+    constexpr span(const span &) = default;
 
     // convertible
     template <typename OtherValueType, std::ptrdiff_t... OtherDimensions,
-        typename BaseType = basic_array_view<ValueType, static_bounds<FirstDimension, RestDimensions...>>,
-        typename OtherBaseType = basic_array_view<OtherValueType, static_bounds<OtherDimensions...>>,
+        typename BaseType = basic_span<ValueType, static_bounds<FirstDimension, RestDimensions...>>,
+        typename OtherBaseType = basic_span<OtherValueType, static_bounds<OtherDimensions...>>,
         typename Dummy = std::enable_if_t<std::is_convertible<OtherBaseType, BaseType>::value>
     >
-    constexpr array_view(const array_view<OtherValueType, OtherDimensions...> &av)
-        : Base(static_cast<const typename array_view<OtherValueType, OtherDimensions...>::Base&>(av))
+    constexpr span(const span<OtherValueType, OtherDimensions...> &av)
+        : Base(static_cast<const typename span<OtherValueType, OtherDimensions...>::Base&>(av))
     {}
 
     // reshape
     // DimCount here is a workaround for a bug in MSVC 2015
     template <typename... Dimensions2, size_t DimCount = sizeof...(Dimensions2), typename = std::enable_if_t<(DimCount > 0)>>
-    constexpr array_view<ValueType, Dimensions2::value...> as_array_view(Dimensions2... dims)
+    constexpr span<ValueType, Dimensions2::value...> as_span(Dimensions2... dims)
     {
-        using BoundsType = typename array_view<ValueType, (Dimensions2::value)...>::bounds_type;
-        auto tobounds = details::static_as_array_view_helper<BoundsType>(dims..., details::Sep{});
+        using BoundsType = typename span<ValueType, (Dimensions2::value)...>::bounds_type;
+        auto tobounds = details::static_as_span_helper<BoundsType>(dims..., details::Sep{});
         details::verifyBoundsReshape(this->bounds(), tobounds);
         return {this->data(), tobounds};
     }
 
     // to bytes array
     template <bool Enabled = std::is_standard_layout<std::decay_t<ValueType>>::value>
-    auto as_bytes() const noexcept -> array_view<const byte>
+    auto as_bytes() const noexcept -> span<const byte>
     {
-        static_assert(Enabled, "The value_type of array_view must be standarded layout");
+        static_assert(Enabled, "The value_type of span must be standarded layout");
         return { reinterpret_cast<const byte*>(this->data()), this->bytes() };
     }
 
     template <bool Enabled = std::is_standard_layout<std::decay_t<ValueType>>::value>
-    auto as_writeable_bytes() const noexcept -> array_view<byte>
+    auto as_writeable_bytes() const noexcept -> span<byte>
     {
-        static_assert(Enabled, "The value_type of array_view must be standarded layout");
+        static_assert(Enabled, "The value_type of span must be standarded layout");
         return { reinterpret_cast<byte*>(this->data()), this->bytes() };
     }
 
     // from bytes array
     template<typename U, bool IsByte = std::is_same<value_type, const byte>::value, typename = std::enable_if_t<IsByte && sizeof...(RestDimensions) == 0>>
-    constexpr auto as_array_view() const noexcept -> array_view<const U, (Base::bounds_type::static_size != dynamic_range ? static_cast<std::ptrdiff_t>(static_cast<size_t>(Base::bounds_type::static_size) / sizeof(U)) : dynamic_range)>
+    constexpr auto as_span() const noexcept -> span<const U, (Base::bounds_type::static_size != dynamic_range ? static_cast<std::ptrdiff_t>(static_cast<size_t>(Base::bounds_type::static_size) / sizeof(U)) : dynamic_range)>
     {
         static_assert(std::is_standard_layout<U>::value && (Base::bounds_type::static_size == dynamic_range || Base::bounds_type::static_size % static_cast<size_type>(sizeof(U)) == 0),
             "Target type must be standard layout and its size must match the byte array size");
@@ -1459,7 +1459,7 @@ public:
     }
 
     template<typename U, bool IsByte = std::is_same<value_type, byte>::value, typename = std::enable_if_t<IsByte && sizeof...(RestDimensions) == 0>>
-    constexpr auto as_array_view() const noexcept -> array_view<U, (Base::bounds_type::static_size != dynamic_range ? static_cast<ptrdiff_t>(static_cast<size_t>(Base::bounds_type::static_size) / sizeof(U)) : dynamic_range)>
+    constexpr auto as_span() const noexcept -> span<U, (Base::bounds_type::static_size != dynamic_range ? static_cast<ptrdiff_t>(static_cast<size_t>(Base::bounds_type::static_size) / sizeof(U)) : dynamic_range)>
     {
         static_assert(std::is_standard_layout<U>::value && (Base::bounds_type::static_size == dynamic_range || Base::bounds_type::static_size % static_cast<size_t>(sizeof(U)) == 0),
             "Target type must be standard layout and its size must match the byte array size");
@@ -1469,42 +1469,42 @@ public:
 
     // section on linear space
     template<std::ptrdiff_t Count>
-    constexpr array_view<ValueType, Count> first() const noexcept
+    constexpr span<ValueType, Count> first() const noexcept
     {
         static_assert(bounds_type::static_size == dynamic_range || Count <= bounds_type::static_size, "Index is out of bound");
         fail_fast_assert(bounds_type::static_size != dynamic_range || Count <= this->size()); // ensures we only check condition when needed
         return { this->data(), Count };
     }
 
-    constexpr array_view<ValueType, dynamic_range> first(size_type count) const noexcept
+    constexpr span<ValueType, dynamic_range> first(size_type count) const noexcept
     {
         fail_fast_assert(count <= this->size());
         return { this->data(), count };
     }
 
     template<std::ptrdiff_t Count>
-    constexpr array_view<ValueType, Count> last() const noexcept
+    constexpr span<ValueType, Count> last() const noexcept
     {
         static_assert(bounds_type::static_size == dynamic_range || Count <= bounds_type::static_size, "Index is out of bound");
         fail_fast_assert(bounds_type::static_size != dynamic_range || Count <= this->size());
         return { this->data() + this->size() - Count, Count };
     }
 
-    constexpr array_view<ValueType, dynamic_range> last(size_type count) const noexcept
+    constexpr span<ValueType, dynamic_range> last(size_type count) const noexcept
     {
         fail_fast_assert(count <= this->size());
         return { this->data() + this->size() - count, count };
     }
 
     template<std::ptrdiff_t Offset, std::ptrdiff_t Count>
-    constexpr array_view<ValueType, Count> sub() const noexcept
+    constexpr span<ValueType, Count> sub() const noexcept
     {
         static_assert(bounds_type::static_size == dynamic_range || ((Offset == 0 || Offset <= bounds_type::static_size) && Offset + Count <= bounds_type::static_size), "Index is out of bound");
         fail_fast_assert(bounds_type::static_size != dynamic_range || ((Offset == 0 || Offset <= this->size()) && Offset + Count <= this->size()));
         return { this->data() + Offset, Count };
     }
 
-    constexpr array_view<ValueType, dynamic_range> sub(size_type offset, size_type count = dynamic_range) const noexcept
+    constexpr span<ValueType, dynamic_range> sub(size_type offset, size_type count = dynamic_range) const noexcept
     {
         fail_fast_assert((offset == 0 || offset <= this->size()) && (count == dynamic_range || (offset + count) <= this->size()));
         return { this->data() + offset, count == dynamic_range ? this->length() - offset : count };
@@ -1532,7 +1532,7 @@ public:
     }
 
     // section
-    constexpr strided_array_view<ValueType, rank> section(index_type origin, index_type extents) const
+    constexpr strided_span<ValueType, rank> section(index_type origin, index_type extents) const
     {
         size_type size = this->bounds().total_size() - this->bounds().linearize(origin);
         return{ &this->operator[](origin), size, strided_bounds<rank> {extents, details::make_stride(Base::bounds())} };
@@ -1544,7 +1544,7 @@ public:
     }
     
         template <bool Enabled = (rank > 1), typename Dummy = std::enable_if_t<Enabled>>
-    constexpr array_view<ValueType, RestDimensions...> operator[](size_type idx) const
+    constexpr span<ValueType, RestDimensions...> operator[](size_type idx) const
     {
         auto ret = Base::operator[](idx);
         return{ ret.data(), ret.bounds() };
@@ -1559,63 +1559,63 @@ public:
 };
 
 template <typename T, std::ptrdiff_t... Dimensions>
-constexpr auto as_array_view(T* const& ptr, dim<Dimensions>... args) -> array_view<std::remove_all_extents_t<T>, Dimensions...>
+constexpr auto as_span(T* const& ptr, dim<Dimensions>... args) -> span<std::remove_all_extents_t<T>, Dimensions...>
 {
-    return {reinterpret_cast<std::remove_all_extents_t<T>*>(ptr), details::static_as_array_view_helper<static_bounds<Dimensions...>>(args..., details::Sep{})};
+    return {reinterpret_cast<std::remove_all_extents_t<T>*>(ptr), details::static_as_span_helper<static_bounds<Dimensions...>>(args..., details::Sep{})};
 }
 
 template <typename T>
-constexpr auto as_array_view (T* arr, std::ptrdiff_t len) -> typename details::ArrayViewArrayTraits<T, dynamic_range>::type
+constexpr auto as_span (T* arr, std::ptrdiff_t len) -> typename details::ArrayViewArrayTraits<T, dynamic_range>::type
 {
     return {reinterpret_cast<std::remove_all_extents_t<T>*>(arr), len};
 }
 
 template <typename T, size_t N>
-constexpr auto as_array_view (T (&arr)[N]) -> typename details::ArrayViewArrayTraits<T, N>::type
+constexpr auto as_span (T (&arr)[N]) -> typename details::ArrayViewArrayTraits<T, N>::type
 {
     return {arr};
 }
 
 template <typename T, size_t N>
-constexpr array_view<const T, N> as_array_view(const std::array<T, N> &arr)
+constexpr span<const T, N> as_span(const std::array<T, N> &arr)
 {
     return {arr};
 }
 
 template <typename T, size_t N>
-constexpr array_view<const T, N> as_array_view(const std::array<T, N> &&) = delete;
+constexpr span<const T, N> as_span(const std::array<T, N> &&) = delete;
 
 template <typename T, size_t N>
-constexpr array_view<T, N> as_array_view(std::array<T, N> &arr)
+constexpr span<T, N> as_span(std::array<T, N> &arr)
 {
     return {arr};
 }
 
 template <typename T>
-constexpr array_view<T, dynamic_range> as_array_view(T *begin, T *end)
+constexpr span<T, dynamic_range> as_span(T *begin, T *end)
 {
     return {begin, end};
 }
 
 template <typename Cont>
-constexpr auto as_array_view(Cont &arr) -> std::enable_if_t<!details::is_array_view<std::decay_t<Cont>>::value,
-    array_view<std::remove_reference_t<decltype(arr.size(), *arr.data())>, dynamic_range>>
+constexpr auto as_span(Cont &arr) -> std::enable_if_t<!details::is_span<std::decay_t<Cont>>::value,
+    span<std::remove_reference_t<decltype(arr.size(), *arr.data())>, dynamic_range>>
 {
     fail_fast_assert(arr.size() < PTRDIFF_MAX);
     return {arr.data(), static_cast<std::ptrdiff_t>(arr.size())};
 }
 
 template <typename Cont>
-constexpr auto as_array_view(Cont &&arr) -> std::enable_if_t<!details::is_array_view<std::decay_t<Cont>>::value,
-    array_view<std::remove_reference_t<decltype(arr.size(), *arr.data())>, dynamic_range>> = delete;
+constexpr auto as_span(Cont &&arr) -> std::enable_if_t<!details::is_span<std::decay_t<Cont>>::value,
+    span<std::remove_reference_t<decltype(arr.size(), *arr.data())>, dynamic_range>> = delete;
 
 template <typename ValueType, size_t Rank>
-class strided_array_view : public basic_array_view<ValueType, strided_bounds<Rank>>
+class strided_span : public basic_span<ValueType, strided_bounds<Rank>>
 {
-    using Base = basic_array_view<ValueType, strided_bounds<Rank>>;
+    using Base = basic_span<ValueType, strided_bounds<Rank>>;
 
     template<typename OtherValue, size_t OtherRank>
-    friend class strided_array_view;
+    friend class strided_span;
 
 public:
     using Base::rank;
@@ -1630,36 +1630,36 @@ public:
     
     // from static array of size N
     template<size_type N>
-    strided_array_view(value_type(&values)[N], bounds_type bounds) : Base(values, std::move(bounds))
+    strided_span(value_type(&values)[N], bounds_type bounds) : Base(values, std::move(bounds))
     {
         fail_fast_assert(this->bounds().total_size() <= N, "Bounds cross data boundaries");
     }
 
     // from raw data
-    strided_array_view(pointer ptr, size_type size, bounds_type bounds): Base(ptr, std::move(bounds))
+    strided_span(pointer ptr, size_type size, bounds_type bounds): Base(ptr, std::move(bounds))
     {
         fail_fast_assert(this->bounds().total_size() <= size, "Bounds cross data boundaries");
     }
 
     // from array view
     template <std::ptrdiff_t... Dimensions, typename Dummy = std::enable_if<sizeof...(Dimensions) == Rank>>
-    strided_array_view(array_view<ValueType, Dimensions...> av, bounds_type bounds) : Base(av.data(), std::move(bounds))
+    strided_span(span<ValueType, Dimensions...> av, bounds_type bounds) : Base(av.data(), std::move(bounds))
     {
         fail_fast_assert(this->bounds().total_size() <= av.bounds().total_size(), "Bounds cross data boundaries");
     }
     
     // convertible
     template <typename OtherValueType,
-        typename BaseType = basic_array_view<ValueType, strided_bounds<Rank>>,
-        typename OtherBaseType = basic_array_view<OtherValueType, strided_bounds<Rank>>,
+        typename BaseType = basic_span<ValueType, strided_bounds<Rank>>,
+        typename OtherBaseType = basic_span<OtherValueType, strided_bounds<Rank>>,
         typename Dummy = std::enable_if_t<std::is_convertible<OtherBaseType, BaseType>::value>
     >
-    constexpr strided_array_view(const strided_array_view<OtherValueType, Rank> &av) : Base(static_cast<const typename strided_array_view<OtherValueType, Rank>::Base &>(av)) // static_cast is required
+    constexpr strided_span(const strided_span<OtherValueType, Rank> &av) : Base(static_cast<const typename strided_span<OtherValueType, Rank>::Base &>(av)) // static_cast is required
     {}
 
     // convert from bytes
         template <typename OtherValueType>
-        strided_array_view<typename std::enable_if<std::is_same<value_type, const byte>::value, OtherValueType>::type, rank> as_strided_array_view() const 
+        strided_span<typename std::enable_if<std::is_same<value_type, const byte>::value, OtherValueType>::type, rank> as_strided_span() const 
     {
         static_assert((sizeof(OtherValueType) >= sizeof(value_type)) && (sizeof(OtherValueType) % sizeof(value_type) == 0), "OtherValueType should have a size to contain a multiple of ValueTypes");
         auto d = static_cast<size_type>(sizeof(OtherValueType) / sizeof(value_type));
@@ -1668,7 +1668,7 @@ public:
         return{ (OtherValueType*)this->data(), size, bounds_type{ resize_extent(this->bounds().index_bounds(), d), resize_stride(this->bounds().strides(), d)} };
     }
 
-    strided_array_view section(index_type origin, index_type extents) const
+    strided_span section(index_type origin, index_type extents) const
     {
         size_type size = this->bounds().total_size() - this->bounds().linearize(origin);
         return { &this->operator[](origin), size, bounds_type {extents, details::make_stride(Base::bounds())}};
@@ -1680,7 +1680,7 @@ public:
     }
 
     template <bool Enabled = (rank > 1), typename Dummy = std::enable_if_t<Enabled>>
-    constexpr strided_array_view<value_type, rank-1> operator[](size_type idx) const
+    constexpr strided_span<value_type, rank-1> operator[](size_type idx) const
     {
         auto ret = Base::operator[](idx);
         return{ ret.data(), ret.bounds().total_size(), ret.bounds() };
@@ -1722,7 +1722,7 @@ private:
 };
 
 template <typename ArrayView>
-class contiguous_array_view_iterator : public std::iterator<std::random_access_iterator_tag, typename ArrayView::value_type>
+class contiguous_span_iterator : public std::iterator<std::random_access_iterator_tag, typename ArrayView::value_type>
 {
     using Base = std::iterator<std::random_access_iterator_tag, typename ArrayView::value_type>;
 public:
@@ -1732,7 +1732,7 @@ public:
 
 private:
     template <typename ValueType, typename Bounds>
-    friend class basic_array_view;
+    friend class basic_span;
 
     pointer m_pdata;
     const ArrayView * m_validator;
@@ -1740,7 +1740,7 @@ private:
     {
         fail_fast_assert(m_pdata >= m_validator->m_pdata && m_pdata < m_validator->m_pdata + m_validator->size(), "iterator is out of range of the array");
     }
-    contiguous_array_view_iterator (const ArrayView *container, bool isbegin) :
+    contiguous_span_iterator (const ArrayView *container, bool isbegin) :
         m_pdata(isbegin ? container->m_pdata : container->m_pdata + container->size()), m_validator(container) {}
 public:
     reference operator*() const noexcept
@@ -1753,48 +1753,48 @@ public:
         validateThis();
         return m_pdata;
     }
-    contiguous_array_view_iterator& operator++() noexcept
+    contiguous_span_iterator& operator++() noexcept
     {
         ++m_pdata;
         return *this;
     }
-    contiguous_array_view_iterator operator++(int)noexcept
+    contiguous_span_iterator operator++(int)noexcept
     {
         auto ret = *this;
         ++(*this);
         return ret;
     }
-    contiguous_array_view_iterator& operator--() noexcept
+    contiguous_span_iterator& operator--() noexcept
     {
         --m_pdata;
         return *this;
     }
-    contiguous_array_view_iterator operator--(int)noexcept
+    contiguous_span_iterator operator--(int)noexcept
     {
         auto ret = *this;
         --(*this);
         return ret;
     }
-    contiguous_array_view_iterator operator+(difference_type n) const noexcept
+    contiguous_span_iterator operator+(difference_type n) const noexcept
     {
-        contiguous_array_view_iterator ret{ *this };
+        contiguous_span_iterator ret{ *this };
         return ret += n;
     }
-    contiguous_array_view_iterator& operator+=(difference_type n) noexcept
+    contiguous_span_iterator& operator+=(difference_type n) noexcept
     {
         m_pdata += n;
         return *this;
     }
-    contiguous_array_view_iterator operator-(difference_type n) const noexcept
+    contiguous_span_iterator operator-(difference_type n) const noexcept
     {
-        contiguous_array_view_iterator ret{ *this };
+        contiguous_span_iterator ret{ *this };
         return ret -= n;
     }
-    contiguous_array_view_iterator& operator-=(difference_type n) noexcept
+    contiguous_span_iterator& operator-=(difference_type n) noexcept
     {
         return *this += -n;
     }
-    difference_type operator-(const contiguous_array_view_iterator& rhs) const noexcept
+    difference_type operator-(const contiguous_span_iterator& rhs) const noexcept
     {
         fail_fast_assert(m_validator == rhs.m_validator);
         return m_pdata - rhs.m_pdata;
@@ -1803,33 +1803,33 @@ public:
     {
         return *(*this + n);
     }
-    bool operator==(const contiguous_array_view_iterator& rhs) const noexcept
+    bool operator==(const contiguous_span_iterator& rhs) const noexcept
     {
         fail_fast_assert(m_validator == rhs.m_validator);
         return m_pdata == rhs.m_pdata;
     }
-    bool operator!=(const contiguous_array_view_iterator& rhs) const noexcept
+    bool operator!=(const contiguous_span_iterator& rhs) const noexcept
     {
         return !(*this == rhs);
     }
-    bool operator<(const contiguous_array_view_iterator& rhs) const noexcept
+    bool operator<(const contiguous_span_iterator& rhs) const noexcept
     {
         fail_fast_assert(m_validator == rhs.m_validator);
         return m_pdata < rhs.m_pdata;
     }
-    bool operator<=(const contiguous_array_view_iterator& rhs) const noexcept
+    bool operator<=(const contiguous_span_iterator& rhs) const noexcept
     {
         return !(rhs < *this);
     }
-    bool operator>(const contiguous_array_view_iterator& rhs) const noexcept
+    bool operator>(const contiguous_span_iterator& rhs) const noexcept
     {
         return rhs < *this;
     }
-    bool operator>=(const contiguous_array_view_iterator& rhs) const noexcept
+    bool operator>=(const contiguous_span_iterator& rhs) const noexcept
     {
         return !(rhs > *this);
     }
-    void swap(contiguous_array_view_iterator& rhs) noexcept
+    void swap(contiguous_span_iterator& rhs) noexcept
     {
         std::swap(m_pdata, rhs.m_pdata);
         std::swap(m_validator, rhs.m_validator);
@@ -1837,13 +1837,13 @@ public:
 };
 
 template <typename ArrayView>
-contiguous_array_view_iterator<ArrayView> operator+(typename contiguous_array_view_iterator<ArrayView>::difference_type n, const contiguous_array_view_iterator<ArrayView>& rhs) noexcept
+contiguous_span_iterator<ArrayView> operator+(typename contiguous_span_iterator<ArrayView>::difference_type n, const contiguous_span_iterator<ArrayView>& rhs) noexcept
 {
     return rhs + n;
 }
 
 template <typename ArrayView>
-class general_array_view_iterator : public std::iterator<std::random_access_iterator_tag, typename ArrayView::value_type>
+class general_span_iterator : public std::iterator<std::random_access_iterator_tag, typename ArrayView::value_type>
 {
     using Base = std::iterator<std::random_access_iterator_tag, typename ArrayView::value_type>;
 public:
@@ -1853,11 +1853,11 @@ public:
     using typename Base::value_type;
 private:
     template <typename ValueType, typename Bounds>
-    friend class basic_array_view;
+    friend class basic_span;
     
     const ArrayView * m_container;
     typename ArrayView::bounds_type::iterator m_itr;
-    general_array_view_iterator(const ArrayView *container, bool isbegin) :
+    general_span_iterator(const ArrayView *container, bool isbegin) :
         m_container(container), m_itr(isbegin ? m_container->bounds().begin() : m_container->bounds().end())
     {}
 public:
@@ -1869,48 +1869,48 @@ public:
     {
         return &(*m_container)[*m_itr];
     }
-    general_array_view_iterator& operator++() noexcept
+    general_span_iterator& operator++() noexcept
     {
         ++m_itr;
         return *this;
     }
-    general_array_view_iterator operator++(int)noexcept
+    general_span_iterator operator++(int)noexcept
     {
         auto ret = *this;
         ++(*this);
         return ret;
     }
-    general_array_view_iterator& operator--() noexcept
+    general_span_iterator& operator--() noexcept
     {
         --m_itr;
         return *this;
     }
-    general_array_view_iterator operator--(int)noexcept
+    general_span_iterator operator--(int)noexcept
     {
         auto ret = *this;
         --(*this);
         return ret;
     }
-    general_array_view_iterator operator+(difference_type n) const noexcept
+    general_span_iterator operator+(difference_type n) const noexcept
     {
-        general_array_view_iterator ret{ *this };
+        general_span_iterator ret{ *this };
         return ret += n;
     }
-    general_array_view_iterator& operator+=(difference_type n) noexcept
+    general_span_iterator& operator+=(difference_type n) noexcept
     {
         m_itr += n;
         return *this;
     }
-    general_array_view_iterator operator-(difference_type n) const noexcept
+    general_span_iterator operator-(difference_type n) const noexcept
     {
-        general_array_view_iterator ret{ *this };
+        general_span_iterator ret{ *this };
         return ret -= n;
     }
-    general_array_view_iterator& operator-=(difference_type n) noexcept
+    general_span_iterator& operator-=(difference_type n) noexcept
     {
         return *this += -n;
     }
-    difference_type operator-(const general_array_view_iterator& rhs) const noexcept
+    difference_type operator-(const general_span_iterator& rhs) const noexcept
     {
         fail_fast_assert(m_container == rhs.m_container);
         return m_itr - rhs.m_itr;
@@ -1919,33 +1919,33 @@ public:
     {
         return (*m_container)[m_itr[n]];;
     }
-    bool operator==(const general_array_view_iterator& rhs) const noexcept
+    bool operator==(const general_span_iterator& rhs) const noexcept
     {
         fail_fast_assert(m_container == rhs.m_container);
         return m_itr == rhs.m_itr;
     }
-    bool operator !=(const general_array_view_iterator& rhs) const noexcept
+    bool operator !=(const general_span_iterator& rhs) const noexcept
     {
         return !(*this == rhs);
     }
-    bool operator<(const general_array_view_iterator& rhs) const noexcept
+    bool operator<(const general_span_iterator& rhs) const noexcept
     {
         fail_fast_assert(m_container == rhs.m_container);
         return m_itr < rhs.m_itr;
     }
-    bool operator<=(const general_array_view_iterator& rhs) const noexcept
+    bool operator<=(const general_span_iterator& rhs) const noexcept
     {
         return !(rhs < *this);
     }
-    bool operator>(const general_array_view_iterator& rhs) const noexcept
+    bool operator>(const general_span_iterator& rhs) const noexcept
     {
         return rhs < *this;
     }
-    bool operator>=(const general_array_view_iterator& rhs) const noexcept
+    bool operator>=(const general_span_iterator& rhs) const noexcept
     {
         return !(rhs > *this);
     }
-    void swap(general_array_view_iterator& rhs) noexcept
+    void swap(general_span_iterator& rhs) noexcept
     {
         std::swap(m_itr, rhs.m_itr);
         std::swap(m_container, rhs.m_container);
@@ -1953,7 +1953,7 @@ public:
 };
 
 template <typename ArrayView>
-general_array_view_iterator<ArrayView> operator+(typename general_array_view_iterator<ArrayView>::difference_type n, const general_array_view_iterator<ArrayView>& rhs) noexcept
+general_span_iterator<ArrayView> operator+(typename general_span_iterator<ArrayView>::difference_type n, const general_span_iterator<ArrayView>& rhs) noexcept
 {
     return rhs + n;
 }
@@ -1985,4 +1985,4 @@ general_array_view_iterator<ArrayView> operator+(typename general_array_view_ite
 #endif // GSL_THROWS_FOR_TESTING 
 
 
-#endif // GSL_ARRAY_VIEW_H
+#endif // GSL_SPAN_H
diff --git a/include/string_view.h b/include/string_span.h
similarity index 71%
rename from include/string_view.h
rename to include/string_span.h
index b5f73c5..beccee4 100644
--- a/include/string_view.h
+++ b/include/string_span.h
@@ -16,10 +16,10 @@
 
 #pragma once
 
-#ifndef GSL_STRING_VIEW_H
-#define GSL_STRING_VIEW_H
+#ifndef GSL_STRING_SPAN_H
+#define GSL_STRING_SPAN_H
 
-#include "array_view.h"
+#include "span.h"
 #include <cstring>
 
 namespace gsl
@@ -47,39 +47,36 @@ template<std::ptrdiff_t Max = dynamic_range>
 using wzstring = wchar_t*;
 
 //
-// string_view and relatives
+// string_span and relatives
 //
 // Note that Extent is always single-dimension only
-// Note that SizeType is defaulted to be smaller than size_t which is the array_view default
-//
-// TODO (neilmac) once array_view regains configurable size_type, update these typedef's
 //
 template <class CharT, std::ptrdiff_t Extent = dynamic_range>
-using basic_string_view = array_view<CharT, Extent>;
+using basic_string_span = span<CharT, Extent>;
 
 template<std::ptrdiff_t Extent = dynamic_range>
-using string_view = basic_string_view<char, Extent>;
+using string_span = basic_string_span<char, Extent>;
 
 template<std::ptrdiff_t Extent = dynamic_range>
-using cstring_view = basic_string_view<const char, Extent>;
+using cstring_span = basic_string_span<const char, Extent>;
 
 template<std::ptrdiff_t Extent = dynamic_range>
-using wstring_view = basic_string_view<wchar_t, Extent>;
+using wstring_span = basic_string_span<wchar_t, Extent>;
 
 template<std::ptrdiff_t Extent = dynamic_range>
-using cwstring_view = basic_string_view<const wchar_t, Extent>;
+using cwstring_span = basic_string_span<const wchar_t, Extent>;
 
 
 //
 // ensure_sentinel() 
 //
-// Provides a way to obtain an array_view from a contiguous sequence
+// Provides a way to obtain an span from a contiguous sequence
 // that ends with a (non-inclusive) sentinel value.
 //
 // Will fail-fast if sentinel cannot be found before max elements are examined.
 //
 template<class T, const T Sentinel>
-array_view<T, dynamic_range> ensure_sentinel(const T* seq, std::ptrdiff_t max = PTRDIFF_MAX)
+span<T, dynamic_range> ensure_sentinel(const T* seq, std::ptrdiff_t max = PTRDIFF_MAX)
 {
     auto cur = seq;
     while ((cur - seq) < max && *cur != Sentinel) ++cur;
@@ -89,56 +86,56 @@ array_view<T, dynamic_range> ensure_sentinel(const T* seq, std::ptrdiff_t max =
 
 
 //
-// ensure_z - creates a string_view for a czstring or cwzstring.
+// ensure_z - creates a string_span for a czstring or cwzstring.
 // Will fail fast if a null-terminator cannot be found before
 // the limit of size_type.
 //
 template<class T>
-inline basic_string_view<T, dynamic_range> ensure_z(T* const & sz, std::ptrdiff_t max = PTRDIFF_MAX)
+inline basic_string_span<T, dynamic_range> ensure_z(T* const & sz, std::ptrdiff_t max = PTRDIFF_MAX)
 {
     return ensure_sentinel<T, 0>(sz, max);
 }
 
 // TODO (neilmac) there is probably a better template-magic way to get the const and non-const overloads to share an implementation
-inline basic_string_view<char, dynamic_range> ensure_z(char* const& sz, std::ptrdiff_t max)
+inline basic_string_span<char, dynamic_range> ensure_z(char* const& sz, std::ptrdiff_t max)
 {
     auto len = strnlen(sz, max);
     fail_fast_assert(sz[len] == 0);
     return{ sz, static_cast<std::ptrdiff_t>(len) };
 }
 
-inline basic_string_view<const char, dynamic_range> ensure_z(const char* const& sz, std::ptrdiff_t max)
+inline basic_string_span<const char, dynamic_range> ensure_z(const char* const& sz, std::ptrdiff_t max)
 {
     auto len = strnlen(sz, max);
     fail_fast_assert(sz[len] == 0); return{ sz, static_cast<std::ptrdiff_t>(len) };
 }
 
-inline basic_string_view<wchar_t, dynamic_range> ensure_z(wchar_t* const& sz, std::ptrdiff_t max)
+inline basic_string_span<wchar_t, dynamic_range> ensure_z(wchar_t* const& sz, std::ptrdiff_t max)
 {
     auto len = wcsnlen(sz, max);
     fail_fast_assert(sz[len] == 0); return{ sz, static_cast<std::ptrdiff_t>(len) };
 }
 
-inline basic_string_view<const wchar_t, dynamic_range> ensure_z(const wchar_t* const& sz, std::ptrdiff_t max)
+inline basic_string_span<const wchar_t, dynamic_range> ensure_z(const wchar_t* const& sz, std::ptrdiff_t max)
 {
     auto len = wcsnlen(sz, max);
     fail_fast_assert(sz[len] == 0); return{ sz, static_cast<std::ptrdiff_t>(len) };
 }
 
 template<class T, size_t N>
-basic_string_view<T, dynamic_range> ensure_z(T(&sz)[N]) { return ensure_z(&sz[0], static_cast<std::ptrdiff_t>(N)); }
+basic_string_span<T, dynamic_range> ensure_z(T(&sz)[N]) { return ensure_z(&sz[0], static_cast<std::ptrdiff_t>(N)); }
 
 template<class Cont>
-basic_string_view<typename std::remove_pointer<typename Cont::pointer>::type, dynamic_range> ensure_z(Cont& cont)
+basic_string_span<typename std::remove_pointer<typename Cont::pointer>::type, dynamic_range> ensure_z(Cont& cont)
 {
     return ensure_z(cont.data(), cont.length());
 }
 
 //
-// to_string() allow (explicit) conversions from string_view to string
+// to_string() allow (explicit) conversions from string_span to string
 //
 template<class CharT, size_t Extent>
-std::basic_string<typename std::remove_const<CharT>::type> to_string(basic_string_view<CharT, Extent> view)
+std::basic_string<typename std::remove_const<CharT>::type> to_string(basic_string_span<CharT, Extent> view)
 {
     return{ view.data(), view.length() };
 }
@@ -148,11 +145,11 @@ template<class CharT, size_t Extent = dynamic_range>
 class basic_zstring_builder
 {
 public:
-    using string_view_type = basic_string_view<CharT, Extent>;
+    using string_span_type = basic_string_span<CharT, Extent>;
     using value_type = CharT;
     using pointer = CharT*;
-    using size_type = typename string_view_type::size_type;
-    using iterator = typename string_view_type::iterator;
+    using size_type = typename string_span_type::size_type;
+    using iterator = typename string_span_type::iterator;
 
     basic_zstring_builder(CharT* data, size_type length) : sv_(data, length) {}
 
@@ -160,18 +157,18 @@ public:
     basic_zstring_builder(CharT(&arr)[Size]) : sv_(arr) {}
 
     pointer data() const { return sv_.data(); }
-    string_view_type view() const { return sv_; }
+    string_span_type view() const { return sv_; }
 
     size_type length() const { return sv_.length(); }
 
     pointer assume0() const { return data(); }
-    string_view_type ensure_z() const { return gsl::ensure_z(sv_); }
+    string_span_type ensure_z() const { return gsl::ensure_z(sv_); }
 
     iterator begin() const { return sv_.begin(); }
     iterator end() const { return sv_.end(); }
 
 private:
-    string_view_type sv_;
+    string_span_type sv_;
 };
 
 template <size_t Max = dynamic_range>
@@ -181,4 +178,4 @@ template <size_t Max = dynamic_range>
 using wzstring_builder = basic_zstring_builder<wchar_t, Max>;
 }
 
-#endif // GSL_STRING_VIEW_H
+#endif // GSL_STRING_SPAN_H
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 5e4c395..3435a7f 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -43,8 +43,8 @@ function(add_gsl_test name)
     )
 endfunction()
 
-add_gsl_test(array_view_tests)
-add_gsl_test(string_view_tests)
+add_gsl_test(span_tests)
+add_gsl_test(string_span_tests)
 add_gsl_test(at_tests)
 add_gsl_test(bounds_tests)
 add_gsl_test(notnull_tests)
diff --git a/tests/bounds_tests.cpp b/tests/bounds_tests.cpp
index aacf3d8..53c44d1 100644
--- a/tests/bounds_tests.cpp
+++ b/tests/bounds_tests.cpp
@@ -15,7 +15,7 @@
 ///////////////////////////////////////////////////////////////////////////////
 
 #include <UnitTest++/UnitTest++.h> 
-#include <array_view.h>
+#include <span.h>
 #include <vector>
 
 using namespace std;
@@ -55,7 +55,7 @@ SUITE(bounds_test)
 		auto itr = bounds.begin();
 	
 #ifdef CONFIRM_COMPILATION_ERRORS
-		array_view<int, 4, dynamic_range, 2> av(nullptr, bounds);
+		span<int, 4, dynamic_range, 2> av(nullptr, bounds);
 	
 		auto itr2 = av.cbegin();
 	
diff --git a/tests/array_view_tests.cpp b/tests/span_tests.cpp
similarity index 63%
rename from tests/array_view_tests.cpp
rename to tests/span_tests.cpp
index dd2067f..4c21116 100644
--- a/tests/array_view_tests.cpp
+++ b/tests/span_tests.cpp
@@ -15,7 +15,7 @@
 ///////////////////////////////////////////////////////////////////////////////
 
 #include <UnitTest++/UnitTest++.h> 
-#include <array_view.h>
+#include <span.h>
 
 #include <string>
 #include <vector>
@@ -32,11 +32,11 @@ namespace
 	struct DerivedClass : BaseClass {};
 }
 
-SUITE(array_view_tests)
+SUITE(span_tests)
 {
 	TEST(basics)
 	{
-		auto ptr = as_array_view(new int[10], 10);
+		auto ptr = as_span(new int[10], 10);
 		fill(ptr.begin(), ptr.end(), 99);
 		for (int num : ptr)
 		{
@@ -49,45 +49,45 @@ SUITE(array_view_tests)
 		static_bounds<4, dynamic_range, 2> bounds{ 3 };
 	
 #ifdef CONFIRM_COMPILATION_ERRORS
-		array_view<int, 4, dynamic_range, 2> av(nullptr, bounds);
+		span<int, 4, dynamic_range, 2> av(nullptr, bounds);
 		av.extent();
 		av.extent<2>();
 		av[8][4][3];
 #endif
 	}
 
-	TEST (array_view_convertible)
+	TEST (span_convertible)
 	{
 #ifdef CONFIRM_COMPILATION_ERRORS
-		array_view<int, 7, 4, 2> av1(nullptr, b1);
+		span<int, 7, 4, 2> av1(nullptr, b1);
 #endif
 	
-		auto f = [&]() { array_view<int, 7, 4, 2> av1(nullptr); };
+		auto f = [&]() { span<int, 7, 4, 2> av1(nullptr); };
 		CHECK_THROW(f(), fail_fast); 
 		
-		array_view<int, 7, dynamic_range, 2> av1(nullptr);
+		span<int, 7, dynamic_range, 2> av1(nullptr);
 
 #ifdef CONFIRM_COMPILATION_ERRORS
 		static_bounds<size_t, 7, dynamic_range, 2> b12(b11);
 		b12 = b11;
 		b11 = b12;
 	
-		array_view<int, dynamic_range> av1 = nullptr;
-		array_view<int, 7, dynamic_range, 2> av2(av1);
-		array_view<int, 7, 4, 2> av2(av1);
+		span<int, dynamic_range> av1 = nullptr;
+		span<int, 7, dynamic_range, 2> av2(av1);
+		span<int, 7, 4, 2> av2(av1);
 #endif
 
-		array_view<DerivedClass> avd;
+		span<DerivedClass> avd;
 #ifdef CONFIRM_COMPILATION_ERRORS
-		array_view<BaseClass> avb = avd;
+		span<BaseClass> avb = avd;
 #endif
-		array_view<const DerivedClass> avcd = avd;
+		span<const DerivedClass> avcd = avd;
 	}
 
 	TEST(boundary_checks)
 	{
 		int arr[10][2];
-		auto av = as_array_view(arr);
+		auto av = as_span(arr);
 
 		fill(begin(av), end(av), 0);
 
@@ -102,32 +102,32 @@ SUITE(array_view_tests)
 		CHECK_THROW((av[{10,2}]), fail_fast);
 	}
 
-	void overloaded_func(array_view<const int, dynamic_range, 3, 5> exp, int expected_value) {
+	void overloaded_func(span<const int, dynamic_range, 3, 5> exp, int expected_value) {
 		for (auto val : exp)
 		{
 			CHECK(val == expected_value);
 		}
 	}
 
-	void overloaded_func(array_view<const char, dynamic_range, 3, 5> exp, char expected_value) {
+	void overloaded_func(span<const char, dynamic_range, 3, 5> exp, char expected_value) {
 		for (auto val : exp)
 		{
 			CHECK(val == expected_value);
 		}
 	}
 
-	void fixed_func(array_view<int, 3, 3, 5> exp, int expected_value) {
+	void fixed_func(span<int, 3, 3, 5> exp, int expected_value) {
 		for (auto val : exp)
 		{
 			CHECK(val == expected_value);
 		}
 	}
 
-	TEST(array_view_parameter_test)
+	TEST(span_parameter_test)
 	{
 		auto data = new int[4][3][5];
 
-		auto av = as_array_view(data, 4);
+		auto av = as_span(data, 4);
 
 		CHECK(av.size() == 60);
 
@@ -138,7 +138,7 @@ SUITE(array_view_tests)
 		CHECK(count == 34 * 60);
 		overloaded_func(av, 34);
 
-		overloaded_func(av.as_array_view(dim<>(4), dim<>(3), dim<>(5)), 34);
+		overloaded_func(av.as_span(dim<>(4), dim<>(3), dim<>(5)), 34);
 
 		//fixed_func(av, 34);
 		delete[] data;
@@ -153,7 +153,7 @@ SUITE(array_view_tests)
 		auto image_ptr = new int[imgSize][3];
 
 		// size check will be done
-		auto image_view = as_array_view(image_ptr, imgSize).as_array_view(dim<>(height), dim<>(width), dim<3>());
+		auto image_view = as_span(image_ptr, imgSize).as_span(dim<>(height), dim<>(width), dim<3>());
 
 		iota(image_view.begin(), image_view.end(), 1);
 
@@ -178,12 +178,12 @@ SUITE(array_view_tests)
 		}
 	}
 
-	TEST(array_view_factory_test)
+	TEST(span_factory_test)
 	{
 		{
 			int * arr = new int[150];
 
-			auto av = as_array_view(arr, dim<10>(), dim<>(3), dim<5>());
+			auto av = as_span(arr, dim<10>(), dim<>(3), dim<5>());
 
 			fill(av.begin(), av.end(), 24);
 			overloaded_func(av, 24);
@@ -192,54 +192,54 @@ SUITE(array_view_tests)
 
 
 			array<int, 15> stdarr{ 0 };
-			auto av2 = as_array_view(stdarr);
-			overloaded_func(av2.as_array_view(dim<>(1), dim<3>(), dim<5>()), 0);
+			auto av2 = as_span(stdarr);
+			overloaded_func(av2.as_span(dim<>(1), dim<3>(), dim<5>()), 0);
 
 
 			string str = "ttttttttttttttt"; // size = 15
 			auto t = str.data();
-			auto av3 = as_array_view(str);
-			overloaded_func(av3.as_array_view(dim<>(1), dim<3>(), dim<5>()), 't');
+			auto av3 = as_span(str);
+			overloaded_func(av3.as_span(dim<>(1), dim<3>(), dim<5>()), 't');
 		}
 
 		{
 			int a[3][4][5];
-			auto av = as_array_view(a);
+			auto av = as_span(a);
 			const int (*b)[4][5];
 			b = a;
-			auto bv = as_array_view(b, 3);
+			auto bv = as_span(b, 3);
 
 			CHECK(av == bv);
 
 			const std::array<double, 3> arr = {0.0, 0.0, 0.0};
-			auto cv = as_array_view(arr);
+			auto cv = as_span(arr);
 
 			vector<float> vec(3);
-			auto dv = as_array_view(vec);
+			auto dv = as_span(vec);
 			
 #ifdef CONFIRM_COMPILATION_ERRORS
-			auto dv2 = as_array_view(std::move(vec));
+			auto dv2 = as_span(std::move(vec));
 #endif
 		}
 	}
 	
 	template <class Bounds> void fn(const Bounds& b) { static_assert(Bounds::static_size == 60, "static bounds is wrong size"); }
-	TEST (array_view_reshape_test)
+	TEST (span_reshape_test)
 	{
 		int a[3][4][5];
-		auto av = as_array_view(a);
+		auto av = as_span(a);
         	fn(av.bounds());
-		auto av2 = av.as_array_view(dim<60>());
-		auto av3 = av2.as_array_view(dim<3>(), dim<4>(), dim<5>());
-		auto av4 = av3.as_array_view(dim<4>(), dim<>(3), dim<5>());
-		auto av5 = av4.as_array_view(dim<3>(), dim<4>(), dim<5>());
-		auto av6 = av5.as_array_view(dim<12>(), dim<>(5));
+		auto av2 = av.as_span(dim<60>());
+		auto av3 = av2.as_span(dim<3>(), dim<4>(), dim<5>());
+		auto av4 = av3.as_span(dim<4>(), dim<>(3), dim<5>());
+		auto av5 = av4.as_span(dim<3>(), dim<4>(), dim<5>());
+		auto av6 = av5.as_span(dim<12>(), dim<>(5));
 		
 		fill(av6.begin(), av6.end(), 1);
 		
 		auto av7 = av6.as_bytes();
 		
-		auto av8 = av7.as_array_view<int>();
+		auto av8 = av7.as_span<int>();
 
 		CHECK(av8.size() == av6.size());
 		for (auto i = 0; i < av8.size(); i++)
@@ -249,97 +249,97 @@ SUITE(array_view_tests)
 
 #ifdef CONFIRM_COMPILATION_ERRORS
 		struct Foo {char c[11];};
-		auto av9 = av7.as_array_view<Foo>();
+		auto av9 = av7.as_span<Foo>();
 #endif
 	}
 
 
-	TEST (array_view_section_test)
+	TEST (span_section_test)
 	{
 		int a[30][4][5];
 		
-		auto av = as_array_view(a);
+		auto av = as_span(a);
 		auto sub = av.section({15, 0, 0}, gsl::index<3>{2, 2, 2});
 		auto subsub = sub.section({1, 0, 0}, gsl::index<3>{1, 1, 1});
 	}
 
-	TEST(array_view_section)
+	TEST(span_section)
 	{
 		std::vector<int> data(5 * 10);
 		std::iota(begin(data), end(data), 0);
-		const array_view<int, 5, 10> av = as_array_view(data).as_array_view(dim<5>(), dim<10>());
+		const span<int, 5, 10> av = as_span(data).as_span(dim<5>(), dim<10>());
 
-		strided_array_view<int, 2> av_section_1 = av.section({ 1, 2 }, { 3, 4 });
+		strided_span<int, 2> av_section_1 = av.section({ 1, 2 }, { 3, 4 });
 		CHECK((av_section_1[{0, 0}] == 12));
 		CHECK((av_section_1[{0, 1}] == 13));
 		CHECK((av_section_1[{1, 0}] == 22));
 		CHECK((av_section_1[{2, 3}] == 35));
 
-		strided_array_view<int, 2> av_section_2 = av_section_1.section({ 1, 2 }, { 2,2 });
+		strided_span<int, 2> av_section_2 = av_section_1.section({ 1, 2 }, { 2,2 });
 		CHECK((av_section_2[{0, 0}] == 24));
 		CHECK((av_section_2[{0, 1}] == 25));
 		CHECK((av_section_2[{1, 0}] == 34));
 	}
  
-	TEST(strided_array_view_constructors)
+	TEST(strided_span_constructors)
 	{
 		// Check stride constructor
 		{
 			int arr[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
 			const int carr[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
 
-			strided_array_view<int, 1> sav1{ arr, {{9}, {1}} }; // T -> T
+			strided_span<int, 1> sav1{ arr, {{9}, {1}} }; // T -> T
 			CHECK(sav1.bounds().index_bounds() == index<1>{ 9 });
 			CHECK(sav1.bounds().stride() == 1);
 			CHECK(sav1[0] == 1 && sav1[8] == 9);
 
 
-			strided_array_view<const int, 1> sav2{ carr, {{ 4 }, { 2 }} }; // const T -> const T
+			strided_span<const int, 1> sav2{ carr, {{ 4 }, { 2 }} }; // const T -> const T
 			CHECK(sav2.bounds().index_bounds() == index<1>{ 4 });
 			CHECK(sav2.bounds().strides() == index<1>{2});
 			CHECK(sav2[0] == 1 && sav2[3] == 7);
 
-			strided_array_view<int, 2> sav3{ arr, {{ 2, 2 },{ 6, 2 }} }; // T -> const T
+			strided_span<int, 2> sav3{ arr, {{ 2, 2 },{ 6, 2 }} }; // T -> const T
 			CHECK((sav3.bounds().index_bounds() == index<2>{ 2, 2 }));
 			CHECK((sav3.bounds().strides() == index<2>{ 6, 2 }));
 			CHECK((sav3[{0, 0}] == 1 && sav3[{0, 1}] == 3 && sav3[{1, 0}] == 7));
 		}
 
-		// Check array_view constructor
+		// Check span constructor
 		{
 			int arr[] = { 1, 2 };
 
 			// From non-cv-qualified source
 			{
-				const array_view<int> src = arr;
+				const span<int> src = arr;
 
-				strided_array_view<int, 1> sav{ src, {2, 1} };
+				strided_span<int, 1> sav{ src, {2, 1} };
 				CHECK(sav.bounds().index_bounds() == index<1>{ 2 });
 				CHECK(sav.bounds().strides() == index<1>{ 1 });
 				CHECK(sav[1] == 2);
 
 #if _MSC_VER > 1800
-				strided_array_view<const int, 1> sav_c{ {src}, {2, 1} };
+				strided_span<const int, 1> sav_c{ {src}, {2, 1} };
 #else                
-				strided_array_view<const int, 1> sav_c{ array_view<const int>{src}, strided_bounds<1>{2, 1} };
+				strided_span<const int, 1> sav_c{ span<const int>{src}, strided_bounds<1>{2, 1} };
 #endif                
 				CHECK(sav_c.bounds().index_bounds() == index<1>{ 2 });
 				CHECK(sav_c.bounds().strides() == index<1>{ 1 });
 				CHECK(sav_c[1] == 2);
 
 #if _MSC_VER > 1800
-				strided_array_view<volatile int, 1> sav_v{ {src}, {2, 1} };
+				strided_span<volatile int, 1> sav_v{ {src}, {2, 1} };
 #else                
-				strided_array_view<volatile int, 1> sav_v{ array_view<volatile int>{src}, strided_bounds<1>{2, 1} };
+				strided_span<volatile int, 1> sav_v{ span<volatile int>{src}, strided_bounds<1>{2, 1} };
 #endif                
 				CHECK(sav_v.bounds().index_bounds() == index<1>{ 2 });
 				CHECK(sav_v.bounds().strides() == index<1>{ 1 });
 				CHECK(sav_v[1] == 2);
 
 #if _MSC_VER > 1800
-				strided_array_view<const volatile int, 1> sav_cv{ {src}, {2, 1} };
+				strided_span<const volatile int, 1> sav_cv{ {src}, {2, 1} };
 #else                
-				strided_array_view<const volatile int, 1> sav_cv{ array_view<const volatile int>{src}, strided_bounds<1>{2, 1} };
+				strided_span<const volatile int, 1> sav_cv{ span<const volatile int>{src}, strided_bounds<1>{2, 1} };
 #endif                
 				CHECK(sav_cv.bounds().index_bounds() == index<1>{ 2 });
 				CHECK(sav_cv.bounds().strides() == index<1>{ 1 });
@@ -348,17 +348,17 @@ SUITE(array_view_tests)
 
 			// From const-qualified source
 			{
-				const array_view<const int> src{ arr };
+				const span<const int> src{ arr };
 
-				strided_array_view<const int, 1> sav_c{ src, {2, 1} };
+				strided_span<const int, 1> sav_c{ src, {2, 1} };
 				CHECK(sav_c.bounds().index_bounds() == index<1>{ 2 });
 				CHECK(sav_c.bounds().strides() == index<1>{ 1 });
 				CHECK(sav_c[1] == 2);
 
 #if _MSC_VER > 1800
-				strided_array_view<const volatile int, 1> sav_cv{ {src}, {2, 1} };
+				strided_span<const volatile int, 1> sav_cv{ {src}, {2, 1} };
 #else
-				strided_array_view<const volatile int, 1> sav_cv{ array_view<const volatile int>{src}, strided_bounds<1>{2, 1} };
+				strided_span<const volatile int, 1> sav_cv{ span<const volatile int>{src}, strided_bounds<1>{2, 1} };
 #endif                
 				
 				CHECK(sav_cv.bounds().index_bounds() == index<1>{ 2 });
@@ -368,17 +368,17 @@ SUITE(array_view_tests)
 
 			// From volatile-qualified source
 			{
-				const array_view<volatile int> src{ arr };
+				const span<volatile int> src{ arr };
 
-				strided_array_view<volatile int, 1> sav_v{ src, {2, 1} };
+				strided_span<volatile int, 1> sav_v{ src, {2, 1} };
 				CHECK(sav_v.bounds().index_bounds() == index<1>{ 2 });
 				CHECK(sav_v.bounds().strides() == index<1>{ 1 });
 				CHECK(sav_v[1] == 2);
 
 #if _MSC_VER > 1800
-				strided_array_view<const volatile int, 1> sav_cv{ {src}, {2, 1} };
+				strided_span<const volatile int, 1> sav_cv{ {src}, {2, 1} };
 #else
-				strided_array_view<const volatile int, 1> sav_cv{ array_view<const volatile int>{src}, strided_bounds<1>{2, 1} };
+				strided_span<const volatile int, 1> sav_cv{ span<const volatile int>{src}, strided_bounds<1>{2, 1} };
 #endif                
 				CHECK(sav_cv.bounds().index_bounds() == index<1>{ 2 });
 				CHECK(sav_cv.bounds().strides() == index<1>{ 1 });
@@ -387,9 +387,9 @@ SUITE(array_view_tests)
 
 			// From cv-qualified source
 			{
-				const array_view<const volatile int> src{ arr };
+				const span<const volatile int> src{ arr };
 
-				strided_array_view<const volatile int, 1> sav_cv{ src, {2, 1} };
+				strided_span<const volatile int, 1> sav_cv{ src, {2, 1} };
 				CHECK(sav_cv.bounds().index_bounds() == index<1>{ 2 });
 				CHECK(sav_cv.bounds().strides() == index<1>{ 1 });
 				CHECK(sav_cv[1] == 2);
@@ -400,34 +400,34 @@ SUITE(array_view_tests)
 		{
 			int arr[2] = { 4, 5 };
 
-			const array_view<int, 2> av(arr, 2);
-			array_view<const int, 2> av2{ av };
+			const span<int, 2> av(arr, 2);
+			span<const int, 2> av2{ av };
 			CHECK(av2[1] == 5);
 
-			static_assert(std::is_convertible<const array_view<int, 2>, array_view<const int, 2>>::value, "ctor is not implicit!");
+			static_assert(std::is_convertible<const span<int, 2>, span<const int, 2>>::value, "ctor is not implicit!");
 		
-			const strided_array_view<int, 1> src{ arr, {2, 1} };
-			strided_array_view<const int, 1> sav{ src };
+			const strided_span<int, 1> src{ arr, {2, 1} };
+			strided_span<const int, 1> sav{ src };
 			CHECK(sav.bounds().index_bounds() == index<1>{ 2 });
 			CHECK(sav.bounds().stride() == 1);
 			CHECK(sav[1] == 5);
 			
-			static_assert(std::is_convertible<const strided_array_view<int, 1>, strided_array_view<const int, 1>>::value, "ctor is not implicit!");
+			static_assert(std::is_convertible<const strided_span<int, 1>, strided_span<const int, 1>>::value, "ctor is not implicit!");
 		}
 
 		// Check copy constructor
 		{
 			int arr1[2] = { 3, 4 };
-			const strided_array_view<int, 1> src1{ arr1, {2, 1} };
-			strided_array_view<int, 1> sav1{ src1 };
+			const strided_span<int, 1> src1{ arr1, {2, 1} };
+			strided_span<int, 1> sav1{ src1 };
  
 			CHECK(sav1.bounds().index_bounds() == index<1>{ 2 });
 			CHECK(sav1.bounds().stride() == 1);
 			CHECK(sav1[0] == 3);
 
 			int arr2[6] = { 1, 2, 3, 4, 5, 6 };
-			const strided_array_view<const int, 2> src2{ arr2, {{ 3, 2 }, { 2, 1 }} };
-			strided_array_view<const int, 2> sav2{ src2 };
+			const strided_span<const int, 2> src2{ arr2, {{ 3, 2 }, { 2, 1 }} };
+			strided_span<const int, 2> sav2{ src2 };
 			CHECK((sav2.bounds().index_bounds() == index<2>{ 3, 2 }));
 			CHECK((sav2.bounds().strides() == index<2>{ 2, 1 }));
 			CHECK((sav2[{0, 0}] == 1 && sav2[{2, 0}] == 5));
@@ -438,9 +438,9 @@ SUITE(array_view_tests)
 			int arr1[2] = { 1, 2 };
 			int arr2[6] = { 3, 4, 5, 6, 7, 8 };
 
-			const strided_array_view<int, 1> src{ arr1, {{2}, {1}} };
-			strided_array_view<const int, 1> sav{ arr2, {{3}, {2}} };
-			strided_array_view<const int, 1>& sav_ref = (sav = src);
+			const strided_span<int, 1> src{ arr1, {{2}, {1}} };
+			strided_span<const int, 1> sav{ arr2, {{3}, {2}} };
+			strided_span<const int, 1>& sav_ref = (sav = src);
 			CHECK(sav.bounds().index_bounds() == index<1>{ 2 });
 			CHECK(sav.bounds().strides() == index<1>{ 1 });
 			CHECK(sav[0] == 1);
@@ -451,9 +451,9 @@ SUITE(array_view_tests)
 		{
 			int arr1[2] = { 3, 4 };
 			int arr1b[1] = { 0 };
-			const strided_array_view<int, 1> src1{ arr1, {2, 1} };
-			strided_array_view<int, 1> sav1{ arr1b, {1, 1} };
-			strided_array_view<int, 1>& sav1_ref = (sav1 = src1);
+			const strided_span<int, 1> src1{ arr1, {2, 1} };
+			strided_span<int, 1> sav1{ arr1b, {1, 1} };
+			strided_span<int, 1>& sav1_ref = (sav1 = src1);
 			CHECK(sav1.bounds().index_bounds() == index<1>{ 2 });
 			CHECK(sav1.bounds().strides() == index<1>{ 1 });
 			CHECK(sav1[0] == 3);
@@ -461,9 +461,9 @@ SUITE(array_view_tests)
 
 			const int arr2[6] = { 1, 2, 3, 4, 5, 6 };
 			const int arr2b[1] = { 0 };
-			const strided_array_view<const int, 2> src2{ arr2, {{ 3, 2 },{ 2, 1 }} };
-			strided_array_view<const int, 2> sav2{ arr2b, {{ 1, 1 },{ 1, 1 }} };
-			strided_array_view<const int, 2>& sav2_ref = (sav2 = src2);
+			const strided_span<const int, 2> src2{ arr2, {{ 3, 2 },{ 2, 1 }} };
+			strided_span<const int, 2> sav2{ arr2b, {{ 1, 1 },{ 1, 1 }} };
+			strided_span<const int, 2>& sav2_ref = (sav2 = src2);
 			CHECK((sav2.bounds().index_bounds() == index<2>{ 3, 2 }));
 			CHECK((sav2.bounds().strides() == index<2>{ 2, 1 }));
 			CHECK((sav2[{0, 0}] == 1 && sav2[{2, 0}] == 5));
@@ -471,23 +471,23 @@ SUITE(array_view_tests)
 		}
 	}
 
-	TEST(strided_array_view_slice)
+	TEST(strided_span_slice)
 	{
 		std::vector<int> data(5 * 10);
 		std::iota(begin(data), end(data), 0);
-		const array_view<int, 5, 10> src = as_array_view(data).as_array_view(dim<5>(), dim<10>());
+		const span<int, 5, 10> src = as_span(data).as_span(dim<5>(), dim<10>());
 
-		const strided_array_view<int, 2> sav{ src, {{5, 10}, {10, 1}} };
+		const strided_span<int, 2> sav{ src, {{5, 10}, {10, 1}} };
 #ifdef CONFIRM_COMPILATION_ERRORS
-		const strided_array_view<const int, 2> csav{ {src},{ { 5, 10 },{ 10, 1 } } };
+		const strided_span<const int, 2> csav{ {src},{ { 5, 10 },{ 10, 1 } } };
 #endif
-		const strided_array_view<const int, 2> csav{ array_view<const int, 5, 10>{ src }, { { 5, 10 },{ 10, 1 } } };
+		const strided_span<const int, 2> csav{ span<const int, 5, 10>{ src }, { { 5, 10 },{ 10, 1 } } };
 
-		strided_array_view<int, 1> sav_sl = sav[2];
+		strided_span<int, 1> sav_sl = sav[2];
 		CHECK(sav_sl[0] == 20);
 		CHECK(sav_sl[9] == 29);
 
-		strided_array_view<const int, 1> csav_sl = sav[3];
+		strided_span<const int, 1> csav_sl = sav[3];
 		CHECK(csav_sl[0] == 30);
 		CHECK(csav_sl[9] == 39);
 
@@ -495,9 +495,9 @@ SUITE(array_view_tests)
 		CHECK(sav[4][9] == 49);
 	}
 
-	TEST(strided_array_view_column_major)
+	TEST(strided_span_column_major)
 	{
-		// strided_array_view may be used to accomodate more peculiar
+		// strided_span may be used to accomodate more peculiar
 		// use cases, such as column-major multidimensional array
 		// (aka. "FORTRAN" layout).
 
@@ -506,7 +506,7 @@ SUITE(array_view_tests)
 			2, 5, 8, 11, 14,
 			3, 6, 9, 12, 15
 		};
-		strided_array_view<int, 2> cm_sav{ cm_array, {{ 5, 3 },{ 1, 5 }} };
+		strided_span<int, 2> cm_sav{ cm_array, {{ 5, 3 },{ 1, 5 }} };
 
 		// Accessing elements
 		CHECK((cm_sav[{0, 0}] == 1));
@@ -515,14 +515,14 @@ SUITE(array_view_tests)
 		CHECK((cm_sav[{4, 2}] == 15));
 
 		// Slice
-		strided_array_view<int, 1> cm_sl = cm_sav[3];
+		strided_span<int, 1> cm_sl = cm_sav[3];
 
 		CHECK(cm_sl[0] == 10);
 		CHECK(cm_sl[1] == 11);
 		CHECK(cm_sl[2] == 12);
 
 		// Section 
-		strided_array_view<int, 2> cm_sec = cm_sav.section( { 2, 1 }, { 3, 2 });
+		strided_span<int, 2> cm_sec = cm_sav.section( { 2, 1 }, { 3, 2 });
 
 		CHECK((cm_sec.bounds().index_bounds() == index<2>{3, 2}));
 		CHECK((cm_sec[{0, 0}] == 8));
@@ -531,10 +531,10 @@ SUITE(array_view_tests)
 		CHECK((cm_sec[{2, 1}] == 15));
 	}
 
-	TEST(strided_array_view_bounds)
+	TEST(strided_span_bounds)
 	{
 		int arr[] = { 0, 1, 2, 3 };
-		array_view<int> av(arr);
+		span<int> av(arr);
 
 		{
 			// incorrect sections
@@ -552,7 +552,7 @@ SUITE(array_view_tests)
 
 		{
 			// zero stride
-			strided_array_view<int, 1> sav{ av,{ { 4 },{} } };
+			strided_span<int, 1> sav{ av,{ { 4 },{} } };
 			CHECK(sav[0] == 0);
 			CHECK(sav[3] == 0);
 			CHECK_THROW(sav[4], fail_fast);
@@ -560,19 +560,19 @@ SUITE(array_view_tests)
 
 		{
 			// zero extent
-			strided_array_view<int, 1> sav{ av,{ {},{ 1 } } };
+			strided_span<int, 1> sav{ av,{ {},{ 1 } } };
 			CHECK_THROW(sav[0], fail_fast);
 		}
 
 		{
 			// zero extent and stride
-			strided_array_view<int, 1> sav{ av,{ {},{} } };
+			strided_span<int, 1> sav{ av,{ {},{} } };
 			CHECK_THROW(sav[0], fail_fast);
 		}
 
 		{
 			// strided array ctor with matching strided bounds 
-			strided_array_view<int, 1> sav{ arr,{ 4, 1 } };
+			strided_span<int, 1> sav{ arr,{ 4, 1 } };
 			CHECK(sav.bounds().index_bounds() == index<1>{ 4 });
 			CHECK(sav[3] == 3);
 			CHECK_THROW(sav[4], fail_fast);
@@ -580,7 +580,7 @@ SUITE(array_view_tests)
 
 		{
 			// strided array ctor with smaller strided bounds 
-			strided_array_view<int, 1> sav{ arr,{ 2, 1 } };
+			strided_span<int, 1> sav{ arr,{ 2, 1 } };
 			CHECK(sav.bounds().index_bounds() == index<1>{ 2 });
 			CHECK(sav[1] == 1);
 			CHECK_THROW(sav[2], fail_fast);
@@ -588,7 +588,7 @@ SUITE(array_view_tests)
 
 		{
 			// strided array ctor with fitting irregular bounds 
-			strided_array_view<int, 1> sav{ arr,{ 2, 3 } };
+			strided_span<int, 1> sav{ arr,{ 2, 3 } };
 			CHECK(sav.bounds().index_bounds() == index<1>{ 2 });
 			CHECK(sav[0] == 0);
 			CHECK(sav[1] == 3);
@@ -597,92 +597,92 @@ SUITE(array_view_tests)
 
 		{
 			// bounds cross data boundaries - from static arrays
-			CHECK_THROW((strided_array_view<int, 1> { arr, { 3, 2 } }), fail_fast);
-			CHECK_THROW((strided_array_view<int, 1> { arr, { 3, 3 } }), fail_fast);
-			CHECK_THROW((strided_array_view<int, 1> { arr, { 4, 5 } }), fail_fast);
-			CHECK_THROW((strided_array_view<int, 1> { arr, { 5, 1 } }), fail_fast);
-			CHECK_THROW((strided_array_view<int, 1> { arr, { 5, 5 } }), fail_fast);
+			CHECK_THROW((strided_span<int, 1> { arr, { 3, 2 } }), fail_fast);
+			CHECK_THROW((strided_span<int, 1> { arr, { 3, 3 } }), fail_fast);
+			CHECK_THROW((strided_span<int, 1> { arr, { 4, 5 } }), fail_fast);
+			CHECK_THROW((strided_span<int, 1> { arr, { 5, 1 } }), fail_fast);
+			CHECK_THROW((strided_span<int, 1> { arr, { 5, 5 } }), fail_fast);
 		}
 
 		{
 			// bounds cross data boundaries - from array view
-			CHECK_THROW((strided_array_view<int, 1> { av, { 3, 2 } }), fail_fast);
-			CHECK_THROW((strided_array_view<int, 1> { av, { 3, 3 } }), fail_fast);
-			CHECK_THROW((strided_array_view<int, 1> { av, { 4, 5 } }), fail_fast);
-			CHECK_THROW((strided_array_view<int, 1> { av, { 5, 1 } }), fail_fast);
-			CHECK_THROW((strided_array_view<int, 1> { av, { 5, 5 } }), fail_fast);
+			CHECK_THROW((strided_span<int, 1> { av, { 3, 2 } }), fail_fast);
+			CHECK_THROW((strided_span<int, 1> { av, { 3, 3 } }), fail_fast);
+			CHECK_THROW((strided_span<int, 1> { av, { 4, 5 } }), fail_fast);
+			CHECK_THROW((strided_span<int, 1> { av, { 5, 1 } }), fail_fast);
+			CHECK_THROW((strided_span<int, 1> { av, { 5, 5 } }), fail_fast);
 		}
 
 		{
 			// bounds cross data boundaries - from dynamic arrays
-			CHECK_THROW((strided_array_view<int, 1> { av.data(), 4, { 3, 2 } }), fail_fast);
-			CHECK_THROW((strided_array_view<int, 1> { av.data(), 4, { 3, 3 } }), fail_fast);
-			CHECK_THROW((strided_array_view<int, 1> { av.data(), 4, { 4, 5 } }), fail_fast);
-			CHECK_THROW((strided_array_view<int, 1> { av.data(), 4, { 5, 1 } }), fail_fast);
-			CHECK_THROW((strided_array_view<int, 1> { av.data(), 4, { 5, 5 } }), fail_fast);
-			CHECK_THROW((strided_array_view<int, 1> { av.data(), 2, { 2, 2 } }), fail_fast);
+			CHECK_THROW((strided_span<int, 1> { av.data(), 4, { 3, 2 } }), fail_fast);
+			CHECK_THROW((strided_span<int, 1> { av.data(), 4, { 3, 3 } }), fail_fast);
+			CHECK_THROW((strided_span<int, 1> { av.data(), 4, { 4, 5 } }), fail_fast);
+			CHECK_THROW((strided_span<int, 1> { av.data(), 4, { 5, 1 } }), fail_fast);
+			CHECK_THROW((strided_span<int, 1> { av.data(), 4, { 5, 5 } }), fail_fast);
+			CHECK_THROW((strided_span<int, 1> { av.data(), 2, { 2, 2 } }), fail_fast);
 		}
 
 #ifdef CONFIRM_COMPILATION_ERRORS
 		{
-			strided_array_view<int, 1> sav0{ av.data(), { 3, 2 } };
-			strided_array_view<int, 1> sav1{ arr, { 1 } };
-			strided_array_view<int, 1> sav2{ arr, { 1,1,1 } };
-			strided_array_view<int, 1> sav3{ av, { 1 } };
-			strided_array_view<int, 1> sav4{ av, { 1,1,1 } };
-			strided_array_view<int, 2> sav5{ av.as_array_view(dim<2>(), dim<2>()), { 1 } };
-			strided_array_view<int, 2> sav6{ av.as_array_view(dim<2>(), dim<2>()), { 1,1,1 } };
-			strided_array_view<int, 2> sav7{ av.as_array_view(dim<2>(), dim<2>()), { { 1,1 },{ 1,1 },{ 1,1 } } };
+			strided_span<int, 1> sav0{ av.data(), { 3, 2 } };
+			strided_span<int, 1> sav1{ arr, { 1 } };
+			strided_span<int, 1> sav2{ arr, { 1,1,1 } };
+			strided_span<int, 1> sav3{ av, { 1 } };
+			strided_span<int, 1> sav4{ av, { 1,1,1 } };
+			strided_span<int, 2> sav5{ av.as_span(dim<2>(), dim<2>()), { 1 } };
+			strided_span<int, 2> sav6{ av.as_span(dim<2>(), dim<2>()), { 1,1,1 } };
+			strided_span<int, 2> sav7{ av.as_span(dim<2>(), dim<2>()), { { 1,1 },{ 1,1 },{ 1,1 } } };
 
 			index<1> index{ 0, 1 };
-			strided_array_view<int, 1> sav8{ arr,{ 1,{ 1,1 } } };
-			strided_array_view<int, 1> sav9{ arr,{ { 1,1 },{ 1,1 } } };
-			strided_array_view<int, 1> sav10{ av,{ 1,{ 1,1 } } };
-			strided_array_view<int, 1> sav11{ av,{ { 1,1 },{ 1,1 } } };
-			strided_array_view<int, 2> sav12{ av.as_array_view(dim<2>(), dim<2>()),{ { 1 },{ 1 } } };
-			strided_array_view<int, 2> sav13{ av.as_array_view(dim<2>(), dim<2>()),{ { 1 },{ 1,1,1 } } };
-			strided_array_view<int, 2> sav14{ av.as_array_view(dim<2>(), dim<2>()),{ { 1,1,1 },{ 1 } } };
+			strided_span<int, 1> sav8{ arr,{ 1,{ 1,1 } } };
+			strided_span<int, 1> sav9{ arr,{ { 1,1 },{ 1,1 } } };
+			strided_span<int, 1> sav10{ av,{ 1,{ 1,1 } } };
+			strided_span<int, 1> sav11{ av,{ { 1,1 },{ 1,1 } } };
+			strided_span<int, 2> sav12{ av.as_span(dim<2>(), dim<2>()),{ { 1 },{ 1 } } };
+			strided_span<int, 2> sav13{ av.as_span(dim<2>(), dim<2>()),{ { 1 },{ 1,1,1 } } };
+			strided_span<int, 2> sav14{ av.as_span(dim<2>(), dim<2>()),{ { 1,1,1 },{ 1 } } };
 		}
 #endif
 	}
 
-	TEST(strided_array_view_type_conversion)
+	TEST(strided_span_type_conversion)
 	{
 		int arr[] = { 0, 1, 2, 3 };
-		array_view<int> av(arr);
+		span<int> av(arr);
 
 		{
-			strided_array_view<int, 1> sav{ av.data(), av.size(), { av.size() / 2, 2 } };
+			strided_span<int, 1> sav{ av.data(), av.size(), { av.size() / 2, 2 } };
 #ifdef CONFIRM_COMPILATION_ERRORS
-			strided_array_view<long, 1> lsav1 = sav.as_strided_array_view<long, 1>();
+			strided_span<long, 1> lsav1 = sav.as_strided_span<long, 1>();
 #endif
 		}
 		{
-			strided_array_view<int, 1> sav{ av, { av.size() / 2, 2 } };
+			strided_span<int, 1> sav{ av, { av.size() / 2, 2 } };
 #ifdef CONFIRM_COMPILATION_ERRORS
-			strided_array_view<long, 1> lsav1 = sav.as_strided_array_view<long, 1>();
+			strided_span<long, 1> lsav1 = sav.as_strided_span<long, 1>();
 #endif
 		}
 
-		array_view<const byte, dynamic_range> bytes = av.as_bytes();
+		span<const byte, dynamic_range> bytes = av.as_bytes();
 
 		// retype strided array with regular strides - from raw data
 		{
 			strided_bounds<2> bounds{ { 2, bytes.size() / 4 }, { bytes.size() / 2, 1 } };
-			strided_array_view<const byte, 2> sav2{ bytes.data(), bytes.size(), bounds };
-			strided_array_view<const int, 2> sav3 = sav2.as_strided_array_view<const int>();
+			strided_span<const byte, 2> sav2{ bytes.data(), bytes.size(), bounds };
+			strided_span<const int, 2> sav3 = sav2.as_strided_span<const int>();
 			CHECK(sav3[0][0] == 0);
 			CHECK(sav3[1][0] == 2);
 			CHECK_THROW(sav3[1][1], fail_fast);
 			CHECK_THROW(sav3[0][1], fail_fast);
 		}
 
-		// retype strided array with regular strides - from array_view
+		// retype strided array with regular strides - from span
 		{
 			strided_bounds<2> bounds{ { 2, bytes.size() / 4 }, { bytes.size() / 2, 1 } };
-			array_view<const byte, 2, dynamic_range> bytes2 = bytes.as_array_view(dim<2>(), dim<>(bytes.size() / 2));
-			strided_array_view<const byte, 2> sav2{ bytes2, bounds };
-			strided_array_view<int, 2> sav3 = sav2.as_strided_array_view<int>();
+			span<const byte, 2, dynamic_range> bytes2 = bytes.as_span(dim<2>(), dim<>(bytes.size() / 2));
+			strided_span<const byte, 2> sav2{ bytes2, bounds };
+			strided_span<int, 2> sav3 = sav2.as_strided_span<int>();
 			CHECK(sav3[0][0] == 0);
 			CHECK(sav3[1][0] == 2);
 			CHECK_THROW(sav3[1][1], fail_fast);
@@ -692,47 +692,47 @@ SUITE(array_view_tests)
 		// retype strided array with not enough elements - last dimension of the array is too small
 		{
 			strided_bounds<2> bounds{ { 4,2 },{ 4, 1 } };
-			array_view<const byte, 2, dynamic_range> bytes2 = bytes.as_array_view(dim<2>(), dim<>(bytes.size() / 2));
-			strided_array_view<const byte, 2> sav2{ bytes2, bounds };
-			CHECK_THROW(sav2.as_strided_array_view<int>(), fail_fast);
+			span<const byte, 2, dynamic_range> bytes2 = bytes.as_span(dim<2>(), dim<>(bytes.size() / 2));
+			strided_span<const byte, 2> sav2{ bytes2, bounds };
+			CHECK_THROW(sav2.as_strided_span<int>(), fail_fast);
 		}
 
 		// retype strided array with not enough elements - strides are too small
 		{
 			strided_bounds<2> bounds{ { 4,2 },{ 2, 1 } };
-			array_view<const byte, 2, dynamic_range> bytes2 = bytes.as_array_view(dim<2>(), dim<>(bytes.size() / 2));
-			strided_array_view<const byte, 2> sav2{ bytes2, bounds };
-			CHECK_THROW(sav2.as_strided_array_view<int>(), fail_fast);
+			span<const byte, 2, dynamic_range> bytes2 = bytes.as_span(dim<2>(), dim<>(bytes.size() / 2));
+			strided_span<const byte, 2> sav2{ bytes2, bounds };
+			CHECK_THROW(sav2.as_strided_span<int>(), fail_fast);
 		}
 
 		// retype strided array with not enough elements - last dimension does not divide by the new typesize
 		{
 			strided_bounds<2> bounds{ { 2,6 },{ 4, 1 } };
-			array_view<const byte, 2, dynamic_range> bytes2 = bytes.as_array_view(dim<2>(), dim<>(bytes.size() / 2));
-			strided_array_view<const byte, 2> sav2{ bytes2, bounds };
-			CHECK_THROW(sav2.as_strided_array_view<int>(), fail_fast);
+			span<const byte, 2, dynamic_range> bytes2 = bytes.as_span(dim<2>(), dim<>(bytes.size() / 2));
+			strided_span<const byte, 2> sav2{ bytes2, bounds };
+			CHECK_THROW(sav2.as_strided_span<int>(), fail_fast);
 		}
 
 		// retype strided array with not enough elements - strides does not divide by the new typesize
 		{
 			strided_bounds<2> bounds{ { 2, 1 },{ 6, 1 } };
-			array_view<const byte, 2, dynamic_range> bytes2 = bytes.as_array_view(dim<2>(), dim<>(bytes.size() / 2));
-			strided_array_view<const byte, 2> sav2{ bytes2, bounds };
-			CHECK_THROW(sav2.as_strided_array_view<int>(), fail_fast);
+			span<const byte, 2, dynamic_range> bytes2 = bytes.as_span(dim<2>(), dim<>(bytes.size() / 2));
+			strided_span<const byte, 2> sav2{ bytes2, bounds };
+			CHECK_THROW(sav2.as_strided_span<int>(), fail_fast);
 		}
 
 		// retype strided array with irregular strides - from raw data
 		{
 			strided_bounds<1> bounds{ bytes.size() / 2, 2 };
-			strided_array_view<const byte, 1> sav2{ bytes.data(), bytes.size(), bounds };
-			CHECK_THROW(sav2.as_strided_array_view<int>(), fail_fast);
+			strided_span<const byte, 1> sav2{ bytes.data(), bytes.size(), bounds };
+			CHECK_THROW(sav2.as_strided_span<int>(), fail_fast);
 		}
 
-		// retype strided array with irregular strides - from array_view
+		// retype strided array with irregular strides - from span
 		{
 			strided_bounds<1> bounds{ bytes.size() / 2, 2 };
-			strided_array_view<const byte, 1> sav2{ bytes, bounds };
-			CHECK_THROW(sav2.as_strided_array_view<int>(), fail_fast);
+			strided_span<const byte, 1> sav2{ bytes, bounds };
+			CHECK_THROW(sav2.as_strided_span<int>(), fail_fast);
 		}
 	}
 
@@ -740,14 +740,14 @@ SUITE(array_view_tests)
 	{
 #ifdef CONFIRM_COMPILATION_ERRORS
 		{
-			array_view<int, 1> empty;
-			strided_array_view<int, 2> empty2;
-			strided_array_view<int, 1> empty3{ nullptr,{ 0, 1 } };
+			span<int, 1> empty;
+			strided_span<int, 2> empty2;
+			strided_span<int, 1> empty3{ nullptr,{ 0, 1 } };
 		}
 #endif
 
 		{
-			array_view<int, 0> empty_av(nullptr);
+			span<int, 0> empty_av(nullptr);
 
 			CHECK(empty_av.bounds().index_bounds() == index<1>{ 0 });
 			CHECK_THROW(empty_av[0], fail_fast);
@@ -760,7 +760,7 @@ SUITE(array_view_tests)
 		}
 
 		{
-			array_view<int> empty_av = {};
+			span<int> empty_av = {};
 			CHECK(empty_av.bounds().index_bounds() == index<1>{ 0 });
 			CHECK_THROW(empty_av[0], fail_fast);
 			CHECK_THROW(empty_av.begin()[0], fail_fast);
@@ -772,8 +772,8 @@ SUITE(array_view_tests)
 		}
 
 		{
-			array_view<int, 0> empty_av(nullptr);
-			strided_array_view<int, 1> empty_sav{ empty_av, { 0, 1 } };
+			span<int, 0> empty_av(nullptr);
+			strided_span<int, 1> empty_sav{ empty_av, { 0, 1 } };
 
 			CHECK(empty_sav.bounds().index_bounds() == index<1>{ 0 });
 			CHECK_THROW(empty_sav[0], fail_fast);
@@ -787,7 +787,7 @@ SUITE(array_view_tests)
 		}
 
 		{
-			strided_array_view<int, 1> empty_sav{ nullptr, 0, { 0, 1 } };
+			strided_span<int, 1> empty_sav{ nullptr, 0, { 0, 1 } };
 
 			CHECK(empty_sav.bounds().index_bounds() == index<1>{ 0 });
 			CHECK_THROW(empty_sav[0], fail_fast);
@@ -810,14 +810,14 @@ SUITE(array_view_tests)
 			arr[2 * i + 1] = i;
 		}
 
-		array_view<int, dynamic_range> av(arr, 8);
+		span<int, dynamic_range> av(arr, 8);
 
 		ptrdiff_t a[1] = { 0 };
 		index<1> i = a;
 
 		CHECK(av[i] == 4);
 
-		auto av2 = av.as_array_view(dim<4>(), dim<>(2));
+		auto av2 = av.as_span(dim<4>(), dim<>(2));
         ptrdiff_t a2[2] = { 0, 1 };
 		index<2> i2 = a2;
 
@@ -955,7 +955,7 @@ SUITE(array_view_tests)
 
 	}
 
-	void iterate_second_column(array_view<int, dynamic_range, dynamic_range> av)
+	void iterate_second_column(span<int, dynamic_range, dynamic_range> av)
 	{
 		auto length = av.size() / 2;
 
@@ -1017,33 +1017,33 @@ SUITE(array_view_tests)
 		}
 	}
 
-	TEST(array_view_section_iteration)
+	TEST(span_section_iteration)
 	{
 		int arr[4][2] = { { 4,0 },{ 5,1 },{ 6,2 },{ 7,3 } };
 
 		// static bounds
 		{
-			array_view<int, 4, 2> av = arr;
+			span<int, 4, 2> av = arr;
 			iterate_second_column(av);
 		}
 		// first bound is dynamic
 		{
-			array_view<int, dynamic_range, 2> av  = arr;
+			span<int, dynamic_range, 2> av  = arr;
 			iterate_second_column(av);
 		}
 		// second bound is dynamic
 		{
-			array_view<int, 4, dynamic_range> av = arr;
+			span<int, 4, dynamic_range> av = arr;
 			iterate_second_column(av);
 		}
 		// both bounds are dynamic
 		{
-			array_view<int, dynamic_range, dynamic_range> av = arr;
+			span<int, dynamic_range, dynamic_range> av = arr;
 			iterate_second_column(av);
 		}
 	}
 
-	TEST(dynamic_array_view_section_iteration)
+	TEST(dynamic_span_section_iteration)
 	{
 		auto height = 4, width = 2;
 		auto size = height * width;
@@ -1054,28 +1054,28 @@ SUITE(array_view_tests)
 			arr[i] = i;
 		}
 
-		auto av = as_array_view(arr, size);
+		auto av = as_span(arr, size);
 
 		// first bound is dynamic
 		{
-			array_view<int, dynamic_range, 2> av2 = av.as_array_view(dim<>(height), dim<>(width));
+			span<int, dynamic_range, 2> av2 = av.as_span(dim<>(height), dim<>(width));
 			iterate_second_column(av2);
 		}
 		// second bound is dynamic
 		{
-			array_view<int, 4, dynamic_range> av2 = av.as_array_view(dim<>(height), dim<>(width));
+			span<int, 4, dynamic_range> av2 = av.as_span(dim<>(height), dim<>(width));
 			iterate_second_column(av2);
 		}
 		// both bounds are dynamic
 		{
-			array_view<int, dynamic_range, dynamic_range> av2 = av.as_array_view(dim<>(height), dim<>(width));
+			span<int, dynamic_range, dynamic_range> av2 = av.as_span(dim<>(height), dim<>(width));
 			iterate_second_column(av2);
 		}
 
 		delete[] arr;
 	}
 
-	void iterate_every_other_element(array_view<int, dynamic_range> av)
+	void iterate_every_other_element(span<int, dynamic_range> av)
 	{
 		// pick every other element
 
@@ -1085,7 +1085,7 @@ SUITE(array_view_tests)
 #else
 		auto bounds = strided_bounds<1>(index<1>{ length }, index<1>{ 2 });
 #endif
-		strided_array_view<int, 1> strided(&av.data()[1], av.size() - 1, bounds);
+		strided_span<int, 1> strided(&av.data()[1], av.size() - 1, bounds);
 
 		CHECK(strided.size() == length);
 		CHECK(strided.bounds().index_bounds()[0] == length);
@@ -1102,24 +1102,24 @@ SUITE(array_view_tests)
 		}
 	}
 
-	TEST(strided_array_view_section_iteration)
+	TEST(strided_span_section_iteration)
 	{
 		int arr[8] = {4,0,5,1,6,2,7,3};
 
 		// static bounds
 		{
-			array_view<int, 8> av(arr, 8);
+			span<int, 8> av(arr, 8);
 			iterate_every_other_element(av);
 		}
 
 		// dynamic bounds
 		{
-			array_view<int, dynamic_range> av(arr, 8);
+			span<int, dynamic_range> av(arr, 8);
 			iterate_every_other_element(av);
 		}
 	}
 
-	TEST(dynamic_strided_array_view_section_iteration)
+	TEST(dynamic_strided_span_section_iteration)
 	{
 		auto arr = new int[8];
 		for (int i = 0; i < 4; ++i)
@@ -1128,13 +1128,13 @@ SUITE(array_view_tests)
 			arr[2 * i + 1] = i;
 		}
 		
-		auto av = as_array_view(arr, 8);
+		auto av = as_span(arr, 8);
 		iterate_every_other_element(av);
 
 		delete[] arr;
 	}
 
-	void iterate_second_slice(array_view<int, dynamic_range, dynamic_range, dynamic_range> av)
+	void iterate_second_slice(span<int, dynamic_range, dynamic_range, dynamic_range> av)
 	{
 		int expected[6] = { 2,3,10,11,18,19 };
 		auto section = av.section({ 0,1,0 }, { 3,1,2 });
@@ -1164,7 +1164,7 @@ SUITE(array_view_tests)
 		}
 	}
 
-	TEST(strided_array_view_section_iteration_3d)
+	TEST(strided_span_section_iteration_3d)
 	{
 		int arr[3][4][2];
 		for (auto i = 0; i < 3; ++i)
@@ -1175,12 +1175,12 @@ SUITE(array_view_tests)
 		}
 
 		{
-			array_view<int, 3, 4, 2> av = arr;
+			span<int, 3, 4, 2> av = arr;
 			iterate_second_slice(av);
 		}
 	}
 
-	TEST(dynamic_strided_array_view_section_iteration_3d)
+	TEST(dynamic_strided_span_section_iteration_3d)
 	{
 		auto height = 12, width = 2;
 		auto size = height * width;
@@ -1192,30 +1192,30 @@ SUITE(array_view_tests)
 		}
 
 		{
-			auto av = as_array_view(arr, 24).as_array_view(dim<3>(),dim<4>(),dim<2>());
+			auto av = as_span(arr, 24).as_span(dim<3>(),dim<4>(),dim<2>());
 			iterate_second_slice(av);
 		}
 
 		{
-			auto av = as_array_view(arr, 24).as_array_view(dim<>(3), dim<4>(), dim<2>());
+			auto av = as_span(arr, 24).as_span(dim<>(3), dim<4>(), dim<2>());
 			iterate_second_slice(av);
 		}
 
 		{
-			auto av = as_array_view(arr, 24).as_array_view(dim<3>(), dim<>(4), dim<2>());
+			auto av = as_span(arr, 24).as_span(dim<3>(), dim<>(4), dim<2>());
 			iterate_second_slice(av);
 		}
 
 		{
-			auto av = as_array_view(arr, 24).as_array_view(dim<3>(), dim<4>(), dim<>(2));
+			auto av = as_span(arr, 24).as_span(dim<3>(), dim<4>(), dim<>(2));
 			iterate_second_slice(av);
 		}
 		delete[] arr;
 	}
 
-	TEST(strided_array_view_conversion)
+	TEST(strided_span_conversion)
 	{
-		// get an array_view of 'c' values from the list of X's
+		// get an span of 'c' values from the list of X's
 
 		struct X { int a; int b; int c; };
 
@@ -1226,7 +1226,7 @@ SUITE(array_view_tests)
 		auto d1 = sizeof(int) * 12 / d2;
 
 		// convert to 4x12 array of bytes
-		auto av = as_array_view(arr, 4).as_bytes().as_array_view(dim<>(d1), dim<>(d2));
+		auto av = as_span(arr, 4).as_bytes().as_span(dim<>(d1), dim<>(d2));
 
 		CHECK(av.bounds().index_bounds()[0] == 4);
 		CHECK(av.bounds().index_bounds()[1] == 12);
@@ -1235,7 +1235,7 @@ SUITE(array_view_tests)
 		auto section = av.section({ 0, 2 * s }, { 4, s }); // { { arr[0].c[0], arr[0].c[1], arr[0].c[2], arr[0].c[3] } , { arr[1].c[0], ... } , ... }
 
 		// convert to array 4x1 array of integers
-		auto cs = section.as_strided_array_view<int>(); // { { arr[0].c }, {arr[1].c } , ... } 
+		auto cs = section.as_strided_span<int>(); // { { arr[0].c }, {arr[1].c } , ... } 
 
 		CHECK(cs.bounds().index_bounds()[0] == 4);
 		CHECK(cs.bounds().index_bounds()[1] == 1);
@@ -1246,10 +1246,10 @@ SUITE(array_view_tests)
 			{ cs.bounds().strides()[1], cs.bounds().strides()[0] }
 		};
 
-		strided_array_view<int, 2> transposed{ cs.data(), cs.bounds().total_size(), reverse_bounds };
+		strided_span<int, 2> transposed{ cs.data(), cs.bounds().total_size(), reverse_bounds };
 		
 		// slice to get a one-dimensional array of c's
-		strided_array_view<int, 1> result = transposed[0];
+		strided_span<int, 1> result = transposed[0];
 
 		CHECK(result.bounds().index_bounds()[0] == 4);
 		CHECK_THROW(result.bounds().index_bounds()[1], fail_fast);
@@ -1265,80 +1265,80 @@ SUITE(array_view_tests)
 
 	TEST(constructors)
 	{
-		array_view<int, dynamic_range> av(nullptr);
+		span<int, dynamic_range> av(nullptr);
 		CHECK(av.length() == 0);
 
-		array_view<int, dynamic_range> av2;
+		span<int, dynamic_range> av2;
 		CHECK(av2.length() == 0);
 
-		array_view<int, dynamic_range> av3(nullptr, 0);
+		span<int, dynamic_range> av3(nullptr, 0);
 		CHECK(av3.length() == 0);
 
 		// Constructing from a nullptr + length is specifically disallowed
-		auto f = [&]() {array_view<int, dynamic_range> av4(nullptr, 2);};
+		auto f = [&]() {span<int, dynamic_range> av4(nullptr, 2);};
 		CHECK_THROW(f(), fail_fast);
 
 		int arr1[2][3];
-		array_view<int, 2, dynamic_range> av5(arr1);
+		span<int, 2, dynamic_range> av5(arr1);
 
 		array<int, 15> arr2;
-		array_view<int, 15> av6(arr2);
+		span<int, 15> av6(arr2);
 
 		vector<int> vec1(19);
-		array_view<int> av7(vec1);
+		span<int> av7(vec1);
 		CHECK(av7.length() == 19);
 
 
-		array_view<int> av8;
+		span<int> av8;
 		CHECK(av8.length() == 0);
-		array_view<int> av9(arr2);
+		span<int> av9(arr2);
 		CHECK(av9.length() == 15);
 
 
 #ifdef CONFIRM_COMPILATION_ERRORS
-		array_view<int, 4> av10;
+		span<int, 4> av10;
 		DerivedClass *p = nullptr;
-		array_view<BaseClass> av11(p, 0);
+		span<BaseClass> av11(p, 0);
 #endif
 	}
 
 	TEST(copyandassignment)
 	{
-		array_view<int, dynamic_range> av1;
+		span<int, dynamic_range> av1;
 
 		int arr[] = {3, 4, 5};
 		av1 = arr;
-		array_view<const int, dynamic_range> av2;
+		span<const int, dynamic_range> av2;
 		av2 = av1;
 	}
 
-	TEST(array_view_first)
+	TEST(span_first)
 	{
 		int arr[5] = { 1, 2, 3, 4, 5 };
 
 		{
-			array_view<int, 5> av = arr;
+			span<int, 5> av = arr;
 			CHECK((av.first<2>().bounds() == static_bounds<2>()));
 			CHECK(av.first<2>().length() == 2);
 			CHECK(av.first(2).length() == 2);
 		}
 
 		{
-			array_view<int, 5> av = arr;
+			span<int, 5> av = arr;
 			CHECK((av.first<0>().bounds() == static_bounds<0>()));
 			CHECK(av.first<0>().length() == 0);
 			CHECK(av.first(0).length() == 0);
 		}
 
 		{
-			array_view<int, 5> av = arr;
+			span<int, 5> av = arr;
 			CHECK((av.first<5>().bounds() == static_bounds<5>()));
 			CHECK(av.first<5>().length() == 5);
 			CHECK(av.first(5).length() == 5);
 		}
 
 		{
-			array_view<int, 5> av = arr;
+			span<int, 5> av = arr;
 #ifdef CONFIRM_COMPILATION_ERRORS
 			CHECK(av.first<6>().bounds() == static_bounds<6>());
 			CHECK(av.first<6>().length() == 6);
@@ -1347,33 +1347,33 @@ SUITE(array_view_tests)
 		}
 
 		{
-			array_view<int, dynamic_range> av;
+			span<int, dynamic_range> av;
 			CHECK((av.first<0>().bounds() == static_bounds<0>()));
 			CHECK(av.first<0>().length() == 0);
 			CHECK(av.first(0).length() == 0);
 		}
 	}
 
-	TEST(array_view_last)
+	TEST(span_last)
 	{
 		int arr[5] = { 1, 2, 3, 4, 5 };
 
 		{
-			array_view<int, 5> av = arr;
+			span<int, 5> av = arr;
 			CHECK((av.last<2>().bounds() == static_bounds<2>()));
 			CHECK(av.last<2>().length() == 2);
 			CHECK(av.last(2).length() == 2);
 		}
 
 		{
-			array_view<int, 5> av = arr;
+			span<int, 5> av = arr;
 			CHECK((av.last<0>().bounds() == static_bounds<0>()));
 			CHECK(av.last<0>().length() == 0);
 			CHECK(av.last(0).length() == 0);
 		}
 
 		{
-			array_view<int, 5> av = arr;
+			span<int, 5> av = arr;
 			CHECK((av.last<5>().bounds() == static_bounds<5>()));
 			CHECK(av.last<5>().length() == 5);
 			CHECK(av.last(5).length() == 5);
@@ -1381,7 +1381,7 @@ SUITE(array_view_tests)
 
 		
 		{
-			array_view<int, 5> av = arr;
+			span<int, 5> av = arr;
 #ifdef CONFIRM_COMPILATION_ERRORS
 			CHECK((av.last<6>().bounds() == static_bounds<6>()));
 			CHECK(av.last<6>().length() == 6);
@@ -1390,17 +1390,17 @@ SUITE(array_view_tests)
 		}
 
 		{
-			array_view<int, dynamic_range> av;
+			span<int, dynamic_range> av;
 			CHECK((av.last<0>().bounds() == static_bounds<0>()));
 			CHECK(av.last<0>().length() == 0);
 			CHECK(av.last(0).length() == 0);
 		}
 	}
 
-	TEST(custmized_array_view_size)
+	TEST(custmized_span_size)
 	{
 		double (*arr)[3][4] = new double[100][3][4];
-		array_view<double, dynamic_range, 3, 4> av1(arr, 10);
+		span<double, dynamic_range, 3, 4> av1(arr, 10);
 
 		struct EffectiveStructure
 		{
@@ -1411,16 +1411,16 @@ SUITE(array_view_tests)
 
 		CHECK_THROW(av1[10][3][4], fail_fast);
 
-		array_view<const double, dynamic_range, 6, 4> av2 = av1.as_array_view(dim<>(5), dim<6>(), dim<4>());
+		span<const double, dynamic_range, 6, 4> av2 = av1.as_span(dim<>(5), dim<6>(), dim<4>());
 		
 	}
 
-	TEST(array_view_sub)
+	TEST(span_sub)
 	{
 		int arr[5] = { 1, 2, 3, 4, 5 };
 
 		{
-			array_view<int, 5> av = arr;
+			span<int, 5> av = arr;
 			CHECK((av.sub<2,2>().bounds() == static_bounds<2>()));
 			CHECK((av.sub<2,2>().length() == 2));
 			CHECK(av.sub(2,2).length() == 2);
@@ -1429,14 +1429,14 @@ SUITE(array_view_tests)
 
 
 		{
-			array_view<int, 5> av = arr;
+			span<int, 5> av = arr;
 			CHECK((av.sub<0,0>().bounds() == static_bounds<0>()));
 			CHECK((av.sub<0,0>().length() == 0));
 			CHECK(av.sub(0,0).length() == 0);
 		}
 
 		{
-			array_view<int, 5> av = arr;
+			span<int, 5> av = arr;
 			CHECK((av.sub<0,5>().bounds() == static_bounds<5>()));
 			CHECK((av.sub<0,5>().length() == 5));
 			CHECK(av.sub(0,5).length() == 5);
@@ -1445,7 +1445,7 @@ SUITE(array_view_tests)
 		}
 
 		{
-			array_view<int, 5> av = arr;
+			span<int, 5> av = arr;
 			CHECK((av.sub<5,0>().bounds() == static_bounds<0>()));
             CHECK((av.sub<5, 0>().length() == 0));
             CHECK(av.sub(5,0).length() == 0);
@@ -1453,7 +1453,7 @@ SUITE(array_view_tests)
 		}
 
 		{
-			array_view<int, dynamic_range> av;
+			span<int, dynamic_range> av;
 			CHECK((av.sub<0,0>().bounds() == static_bounds<0>()));
 			CHECK((av.sub<0,0>().length() == 0));
 			CHECK(av.sub(0,0).length() == 0);
@@ -1461,13 +1461,13 @@ SUITE(array_view_tests)
 		}
 
         {
-            array_view<int> av;
+            span<int> av;
             CHECK(av.sub(0).length() == 0);
             CHECK_THROW(av.sub(1).length(), fail_fast);
         }
 
         {
-            array_view<int> av = arr;
+            span<int> av = arr;
             CHECK(av.sub(0).length() == 5);
             CHECK(av.sub(1).length() == 4);
             CHECK(av.sub(4).length() == 1);
@@ -1479,7 +1479,7 @@ SUITE(array_view_tests)
         }
         
         {
-            array_view<int,5> av = arr;
+            span<int,5> av = arr;
             CHECK(av.sub(0).length() == 5);
             CHECK(av.sub(1).length() == 4);
             CHECK(av.sub(4).length() == 1);
@@ -1491,7 +1491,7 @@ SUITE(array_view_tests)
         }
     }
 
-	void AssertNullEmptyProperties(array_view<int, dynamic_range>& av)
+	void AssertNullEmptyProperties(span<int, dynamic_range>& av)
 	{
 		CHECK(av.length() == 0);
 		CHECK(av.data() == nullptr);
@@ -1508,10 +1508,10 @@ SUITE(array_view_tests)
 
 	TEST(TestNullConstruction)
 	{
-		array_view<int, dynamic_range> av;
+		span<int, dynamic_range> av;
 		AssertNullEmptyProperties(av);
 
-		array_view<int, dynamic_range> av2(nullptr);
+		span<int, dynamic_range> av2(nullptr);
 		AssertNullEmptyProperties(av2);
 	}
 
@@ -1519,13 +1519,13 @@ SUITE(array_view_tests)
 	{
 		int a[] = { 1, 2, 3, 4 };
 
-		array_view<int, dynamic_range> av = { &a[1], 3 };
+		span<int, dynamic_range> av = { &a[1], 3 };
 		CHECK(av.length() == 3);
 
-		array_view<int, dynamic_range> av3 = { a, 2 };
+		span<int, dynamic_range> av3 = { a, 2 };
 		CHECK(av3.length() == 2);
 
-		array_view<int, dynamic_range> av2 = a;
+		span<int, dynamic_range> av2 = a;
 		CHECK(av2.length() == 4);
 	}
 
@@ -1534,11 +1534,11 @@ SUITE(array_view_tests)
 		int a[] = { 1, 2, 3, 4 };
 
 #ifdef CONFIRM_COMPILATION_ERRORS
-		array_view<const int, dynamic_range> cav = a;
-		array_view<int, dynamic_range> av = cav;
+		span<const int, dynamic_range> cav = a;
+		span<int, dynamic_range> av = cav;
 #else
-		array_view<int, dynamic_range> av = a;
-		array_view<const int, dynamic_range> cav = av;			 
+		span<int, dynamic_range> av = a;
+		span<const int, dynamic_range> cav = av;			 
 #endif
 		AssertContentsMatch(av, cav);
 	}
@@ -1547,43 +1547,43 @@ SUITE(array_view_tests)
 	{			
 		int arr[] = { 1, 2, 3, 4 };
 	
-		// converting to an array_view from an equal size array is ok
-		array_view<int, 4> av4 = arr;
+		// converting to an span from an equal size array is ok
+		span<int, 4> av4 = arr;
 		CHECK(av4.length() == 4);
 
 		// converting to dynamic_range a_v is always ok
 		{
-			array_view<int, dynamic_range> av = av4;
+			span<int, dynamic_range> av = av4;
 		}
 		{
-			array_view<int, dynamic_range> av = arr;
+			span<int, dynamic_range> av = arr;
 		}
 
-		// initialization or assignment to static array_view that REDUCES size is NOT ok
+		// initialization or assignment to static span that REDUCES size is NOT ok
 #ifdef CONFIRM_COMPILATION_ERRORS
 		{
-			array_view<int, 2> av2 = arr;
+			span<int, 2> av2 = arr;
 		}
 		{
-			array_view<int, 2> av2 = av4;
+			span<int, 2> av2 = av4;
 		}
 #endif
 
 		{
-			array_view<int, dynamic_range> av = arr;
-			array_view<int, 2> av2 = av;
+			span<int, dynamic_range> av = arr;
+			span<int, 2> av2 = av;
 		}
 
 #ifdef CONFIRM_COMPILATION_ERRORS
 		{
-			array_view<int, dynamic_range> av = arr;
-			array_view<int, 2, 1> av2 = av.as_array_view(dim<2>(), dim<2>());
+			span<int, dynamic_range> av = arr;
+			span<int, 2, 1> av2 = av.as_span(dim<2>(), dim<2>());
 		}
 #endif
 
 		{
-			array_view<int, dynamic_range> av = arr;
-			auto f = [&]() {array_view<int, 2, 1> av2 = av.as_array_view(dim<>(2), dim<>(2));};
+			span<int, dynamic_range> av = arr;
+			auto f = [&]() {span<int, 2, 1> av2 = av.as_span(dim<>(2), dim<>(2));};
 			CHECK_THROW(f(), fail_fast);
 		}
 
@@ -1591,38 +1591,38 @@ SUITE(array_view_tests)
 			
 		// you can convert statically
 		{
-			array_view<int, 2> av2 = {arr, 2};
+			span<int, 2> av2 = {arr, 2};
 		}
 		{
-			array_view<int, 1> av2 = av4.first<1>();
+			span<int, 1> av2 = av4.first<1>();
 		}
 			
 		// ...or dynamically
 		{
-			// NB: implicit conversion to array_view<int,2> from array_view<int,dynamic_range>
-			array_view<int, 1> av2 = av4.first(1); 
+			// NB: implicit conversion to span<int,2> from span<int,dynamic_range>
+			span<int, 1> av2 = av4.first(1); 
 		}
 
-		// initialization or assignment to static array_view that requires size INCREASE is not ok.
+		// initialization or assignment to static span that requires size INCREASE is not ok.
 		int arr2[2]  = { 1, 2 };
 
 #ifdef CONFIRM_COMPILATION_ERRORS
 		{
-			array_view<int, 4> av4 = arr2;
+			span<int, 4> av4 = arr2;
 		}
 		{
-			array_view<int, 2> av2 = arr2;
-			array_view<int, 4> av4 = av2;
+			span<int, 2> av2 = arr2;
+			span<int, 4> av4 = av2;
 		}
 #endif
 		{
-			auto f = [&]() {array_view<int, 4> av4 = {arr2, 2};};
+			auto f = [&]() {span<int, 4> av4 = {arr2, 2};};
 			CHECK_THROW(f(), fail_fast);
 		}
 
 		// this should fail - we are trying to assign a small dynamic a_v to a fixed_size larger one
-		array_view<int, dynamic_range> av = arr2;
-		auto f = [&](){ array_view<int, 4> av2 = av; };
+		span<int, dynamic_range> av = arr2;
+		auto f = [&](){ span<int, 4> av2 = av; };
 		CHECK_THROW(f(), fail_fast);
 	}
 
@@ -1633,13 +1633,13 @@ SUITE(array_view_tests)
 		{
 #ifdef CONFIRM_COMPILATION_ERRORS
 			// you should not be able to get writeable bytes for const objects
-			array_view<const int, dynamic_range> av = a;
+			span<const int, dynamic_range> av = a;
 			auto wav = av.as_writeable_bytes();
 #endif
 		}
 
 		{
-			array_view<int, dynamic_range> av;
+			span<int, dynamic_range> av;
 			auto wav = av.as_writeable_bytes();
 			CHECK(wav.length() == av.length());
 			CHECK(wav.length() == 0);
@@ -1647,7 +1647,7 @@ SUITE(array_view_tests)
 		}
 
 		{
-			array_view<int, dynamic_range> av = a;
+			span<int, dynamic_range> av = a;
 			auto wav = av.as_writeable_bytes();
 			CHECK(wav.data() == (byte*)&a[0]);
 			CHECK(wav.length() == sizeof(a));
@@ -1659,7 +1659,7 @@ SUITE(array_view_tests)
 		int a[] = { 1, 2, 3, 4 };
 
 		{
-			array_view<int, dynamic_range> av = a;
+			span<int, dynamic_range> av = a;
 			auto wav = av.as_writeable_bytes();
 			for (auto& b : wav)
 			{
@@ -1672,7 +1672,7 @@ SUITE(array_view_tests)
 		}
 
 		{
-			array_view<int, dynamic_range> av = a;
+			span<int, dynamic_range> av = a;
 			for (auto& n : av)
 			{
 				n = 1;
@@ -1688,12 +1688,12 @@ SUITE(array_view_tests)
 	{
 		{
 			int arr[10][2];
-			auto av1 = as_array_view(arr);
-			array_view<const int, dynamic_range, 2> av2 = av1;
+			auto av1 = as_span(arr);
+			span<const int, dynamic_range, 2> av2 = av1;
 
 			CHECK(av1 == av2);
 
-			array_view<int, 20> av3 = av1.as_array_view(dim<>(20));
+			span<int, 20> av3 = av1.as_span(dim<>(20));
 			CHECK(av3 == av2 && av3 == av1);
 		}
 
@@ -1717,8 +1717,8 @@ SUITE(array_view_tests)
 		{
 			int arr[] = { 2, 1 }; // bigger
 
-			array_view<int> av1 = nullptr;
-			array_view<int> av2 = arr;
+			span<int> av1 = nullptr;
+			span<int> av2 = arr;
 
 			CHECK(av1 != av2);
 			CHECK(av2 != av1);
@@ -1737,8 +1737,8 @@ SUITE(array_view_tests)
 		{
 			int arr1[] = { 1, 2 };
 			int arr2[] = { 1, 2 };
-			array_view<int> av1 = arr1;
-			array_view<int> av2 = arr2;
+			span<int> av1 = arr1;
+			span<int> av2 = arr2;
 
 			CHECK(av1 == av2);
 			CHECK(!(av1 != av2));
@@ -1757,8 +1757,8 @@ SUITE(array_view_tests)
 		{
 			int arr[] = { 1, 2, 3 };
 
-			array_view<int> av1 = { &arr[0], 2 }; // shorter
-			array_view<int> av2 = arr;            // longer
+			span<int> av1 = { &arr[0], 2 }; // shorter
+			span<int> av2 = arr;            // longer
 
 			CHECK(av1 != av2);
 			CHECK(av2 != av1);
@@ -1778,8 +1778,8 @@ SUITE(array_view_tests)
 			int arr1[] = { 1, 2 }; // smaller
 			int arr2[] = { 2, 1 }; // bigger
 
-			array_view<int> av1 = arr1;
-			array_view<int> av2 = arr2;
+			span<int> av1 = arr1;
+			span<int> av2 = arr2;
 
 			CHECK(av1 != av2);
 			CHECK(av2 != av1);
diff --git a/tests/string_view_tests.cpp b/tests/string_span_tests.cpp
similarity index 78%
rename from tests/string_view_tests.cpp
rename to tests/string_span_tests.cpp
index e553ccd..dc3ccf5 100644
--- a/tests/string_view_tests.cpp
+++ b/tests/string_span_tests.cpp
@@ -15,38 +15,38 @@
 ///////////////////////////////////////////////////////////////////////////////
 
 #include <UnitTest++/UnitTest++.h> 
-#include <string_view.h>
+#include <string_span.h>
 #include <vector>
 #include <cstdlib>
 
 using namespace std;
 using namespace gsl;
 
-SUITE(string_view_tests)
+SUITE(string_span_tests)
 {
 
     TEST(TestLiteralConstruction)
 	{
-        cwstring_view<> v = ensure_z(L"Hello");
+        cwstring_span<> v = ensure_z(L"Hello");
 
         CHECK(5 == v.length());
 
 #ifdef CONFIRM_COMPILATION_ERRORS
-        wstring_view<> v2 = ensure0(L"Hello");
+        wstring_span<> v2 = ensure0(L"Hello");
 #endif
 	}
 
     TEST(TestConstructFromStdString)
     {
         std::string s = "Hello there world";
-        cstring_view<> v = s;
+        cstring_span<> v = s;
         CHECK(v.length() == s.length());
     }
 
     TEST(TestConstructFromStdVector)
     {
         std::vector<char> vec(5, 'h');
-        string_view<> v = vec;
+        string_span<> v = vec;
         CHECK(v.length() == vec.size());
     }
 
@@ -55,25 +55,25 @@ SUITE(string_view_tests)
         wchar_t stack_string[] = L"Hello";
 
         {
-            cwstring_view<> v = ensure_z(stack_string);
+            cwstring_span<> v = ensure_z(stack_string);
             CHECK(v.length() == 5);
             CHECK(v.used_length() == v.length());
         }
 
         {
-            cwstring_view<> v = stack_string;
+            cwstring_span<> v = stack_string;
             CHECK(v.length() == 6);
             CHECK(v.used_length() == v.length());
         }
 
         {
-            wstring_view<> v = ensure_z(stack_string);
+            wstring_span<> v = ensure_z(stack_string);
             CHECK(v.length() == 5);
             CHECK(v.used_length() == v.length());
         }
 
         {
-            wstring_view<> v = stack_string;
+            wstring_span<> v = stack_string;
             CHECK(v.length() == 6);
             CHECK(v.used_length() == v.length());
         }
@@ -82,7 +82,7 @@ SUITE(string_view_tests)
     TEST(TestConstructFromConstCharPointer)
     {
         const char* s = "Hello";
-        cstring_view<> v = ensure_z(s);
+        cstring_span<> v = ensure_z(s);
         CHECK(v.length() == 5);
         CHECK(v.used_length() == v.length());
     }
@@ -90,18 +90,18 @@ SUITE(string_view_tests)
     TEST(TestConversionToConst)
     {
         char stack_string[] = "Hello";
-        string_view<> v = ensure_z(stack_string);
-        cstring_view<> v2 = v; 
+        string_span<> v = ensure_z(stack_string);
+        cstring_span<> v2 = v; 
         CHECK(v.length() == v2.length());
     }
 
     TEST(TestConversionFromConst)
     {
         char stack_string[] = "Hello";
-        cstring_view<> v = ensure_z(stack_string);
+        cstring_span<> v = ensure_z(stack_string);
 #ifdef CONFIRM_COMPILATION_ERRORS
-        string_view<> v2 = v;
-        string_view<> v3 = "Hello";
+        string_span<> v2 = v;
+        string_span<> v3 = "Hello";
 #endif
     }
 }

From caabb40440f44b24b573a0822433ea758b469b96 Mon Sep 17 00:00:00 2001
From: Neil MacIntosh <neilmac@microsoft.com>
Date: Wed, 4 Nov 2015 13:50:57 -0800
Subject: [PATCH 09/43] Rename of array_view/string_view in readme.

Knew I'd miss something!
---
 README.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index c687673..6e84a82 100644
--- a/README.md
+++ b/README.md
@@ -4,11 +4,11 @@ The Guidelines Support Library (GSL) contains functions and types that are sugge
 [C++ Core Guidelines](https://github.com/isocpp/CppCoreGuidelines) maintained by the [Standard C++ Foundation](https://isocpp.org).
 This repo contains Microsoft's implementation of GSL.
 
-The library includes types like `array_view<>`, `string_view<>`, `owner<>` and others.
+The library includes types like `span<T>`, `string_span`, `owner<>` and others.
 
 The entire implementation is provided inline in the headers under the [include](./include) directory.
 
-While some types have been broken out into their own headers (e.g. [include/array_view.h](./include/array_view.h)),
+While some types have been broken out into their own headers (e.g. [include/span.h](./include/span.h)),
 it is simplest to just include [gsl.h](./include/gsl.h) and gain access to the entire library.
 
 > NOTE: We encourage contributions that improve or refine any of the types in this library as well as ports to

From 4e4882bda8dee92d05c11708a016f3409abed963 Mon Sep 17 00:00:00 2001
From: Neil MacIntosh <neilmac@microsoft.com>
Date: Thu, 5 Nov 2015 09:29:30 -0800
Subject: [PATCH 10/43] Added workaround for MSVC 2013 compiler bug.

---
 include/string_span.h       | 56 +++++++++++++++++++++++++++++++++----
 tests/string_span_tests.cpp | 13 +++++++++
 2 files changed, 64 insertions(+), 5 deletions(-)

diff --git a/include/string_span.h b/include/string_span.h
index beccee4..133712e 100644
--- a/include/string_span.h
+++ b/include/string_span.h
@@ -22,6 +22,16 @@
 #include "span.h"
 #include <cstring>
 
+// VS 2013 workarounds
+#ifdef _MSC_VER
+#if _MSC_VER <= 1800
+
+#pragma push_macro("GSL_MSVC_HAS_TYPE_DEDUCTION_BUG") 
+#define GSL_MSVC_HAS_TYPE_DEDUCTION_BUG 
+
+#endif // _MSC_VER <= 1800
+#endif // _MSC_VER
+
 namespace gsl
 {
 //
@@ -34,16 +44,16 @@ namespace gsl
 // type system for these types that will not either incur significant runtime costs or
 // (sometimes needlessly) break existing programs when introduced.
 //
-template<std::ptrdiff_t Max = dynamic_range>
+template<std::ptrdiff_t Extent = dynamic_range>
 using czstring = const char*;
 
-template<std::ptrdiff_t Max = dynamic_range>
+template<std::ptrdiff_t Extent = dynamic_range>
 using cwzstring = const wchar_t*;
 
-template<std::ptrdiff_t Max = dynamic_range>
+template<std::ptrdiff_t Extent = dynamic_range>
 using zstring = char*;
 
-template<std::ptrdiff_t Max = dynamic_range>
+template<std::ptrdiff_t Extent = dynamic_range>
 using wzstring = wchar_t*;
 
 //
@@ -134,12 +144,37 @@ basic_string_span<typename std::remove_pointer<typename Cont::pointer>::type, dy
 //
 // to_string() allow (explicit) conversions from string_span to string
 //
-template<class CharT, size_t Extent>
+#ifndef GSL_MSVC_HAS_TYPE_DEDUCTION_BUG 
+
+template<class CharT, ptrdiff_t Extent>
 std::basic_string<typename std::remove_const<CharT>::type> to_string(basic_string_span<CharT, Extent> view)
+{
+    return{ view.data(), static_cast<size_t>(view.length()) };
+}
+
+#else
+
+std::string to_string(cstring_span<> view)
 {
     return{ view.data(), view.length() };
 }
 
+std::string to_string(string_span<> view)
+{
+    return{ view.data(), view.length() };
+}
+
+std::wstring to_string(cwstring_span<> view)
+{
+    return{ view.data(), view.length() };
+}
+
+std::wstring to_string(wstring_span<> view)
+{
+    return{ view.data(), view.length() };
+}
+
+#endif 
 
 template<class CharT, size_t Extent = dynamic_range>
 class basic_zstring_builder
@@ -178,4 +213,15 @@ template <size_t Max = dynamic_range>
 using wzstring_builder = basic_zstring_builder<wchar_t, Max>;
 }
 
+// VS 2013 workarounds
+#ifdef _MSC_VER
+#if _MSC_VER <= 1800
+
+#pragma pop_macro("GSL_MSVC_HAS_TYPE_DEDUCTION_BUG") 
+#undef GSL_MSVC_HAS_TYPE_DEDUCTION_BUG 
+
+#endif // _MSC_VER <= 1800
+#endif // _MSC_VER
+
+
 #endif // GSL_STRING_SPAN_H
diff --git a/tests/string_span_tests.cpp b/tests/string_span_tests.cpp
index dc3ccf5..ab48fcb 100644
--- a/tests/string_span_tests.cpp
+++ b/tests/string_span_tests.cpp
@@ -22,6 +22,7 @@
 using namespace std;
 using namespace gsl;
 
+
 SUITE(string_span_tests)
 {
 
@@ -104,6 +105,18 @@ SUITE(string_span_tests)
         string_span<> v3 = "Hello";
 #endif
     }
+
+    TEST(TestToString)
+    {
+        auto s = gsl::to_string(cstring_span<>{});
+        CHECK(s.length() == 0);
+
+        char stack_string[] = "Hello";
+        cstring_span<> v = ensure_z(stack_string);
+        auto s2 = gsl::to_string(v);
+        CHECK(s2.length() == v.length());
+        CHECK(s2.length() == 5);
+    }
 }
 
 int main(int, const char *[])

From 31dd90ef31728549fbbb1b6e1f4d53be67175260 Mon Sep 17 00:00:00 2001
From: Rostislav Khlebnikov <r.khlebnikov@gmail.com>
Date: Thu, 5 Nov 2015 17:56:50 +0000
Subject: [PATCH 11/43] added missing inlines

---
 include/string_span.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/string_span.h b/include/string_span.h
index 133712e..68095fa 100644
--- a/include/string_span.h
+++ b/include/string_span.h
@@ -154,22 +154,22 @@ std::basic_string<typename std::remove_const<CharT>::type> to_string(basic_strin
 
 #else
 
-std::string to_string(cstring_span<> view)
+inline std::string to_string(cstring_span<> view)
 {
     return{ view.data(), view.length() };
 }
 
-std::string to_string(string_span<> view)
+inline std::string to_string(string_span<> view)
 {
     return{ view.data(), view.length() };
 }
 
-std::wstring to_string(cwstring_span<> view)
+inline std::wstring to_string(cwstring_span<> view)
 {
     return{ view.data(), view.length() };
 }
 
-std::wstring to_string(wstring_span<> view)
+inline std::wstring to_string(wstring_span<> view)
 {
     return{ view.data(), view.length() };
 }

From 670ffbeb1133caff2f95db3834824c379aa9b0a8 Mon Sep 17 00:00:00 2001
From: Neil MacIntosh <neilmac@microsoft.com>
Date: Wed, 11 Nov 2015 10:37:43 -0800
Subject: [PATCH 12/43] Added note regarding C++14 support requirements.

---
 README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 6e84a82..5743bb3 100644
--- a/README.md
+++ b/README.md
@@ -6,7 +6,7 @@ This repo contains Microsoft's implementation of GSL.
 
 The library includes types like `span<T>`, `string_span`, `owner<>` and others.
 
-The entire implementation is provided inline in the headers under the [include](./include) directory.
+The entire implementation is provided inline in the headers under the [include](./include) directory. The implementation generally assumes a platform that implements C++14 support. There are specific workarounds to support MSVC 2013 and 2015.
 
 While some types have been broken out into their own headers (e.g. [include/span.h](./include/span.h)),
 it is simplest to just include [gsl.h](./include/gsl.h) and gain access to the entire library.

From fc289930ee37a5bd34bf7198fc30948f455cc2f3 Mon Sep 17 00:00:00 2001
From: Neil MacIntosh <neilmac@microsoft.com>
Date: Wed, 11 Nov 2015 20:48:42 -0800
Subject: [PATCH 13/43] Cast size_type for string_span ctor from container.

---
 include/string_span.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/string_span.h b/include/string_span.h
index 68095fa..7194c85 100644
--- a/include/string_span.h
+++ b/include/string_span.h
@@ -138,7 +138,7 @@ basic_string_span<T, dynamic_range> ensure_z(T(&sz)[N]) { return ensure_z(&sz[0]
 template<class Cont>
 basic_string_span<typename std::remove_pointer<typename Cont::pointer>::type, dynamic_range> ensure_z(Cont& cont)
 {
-    return ensure_z(cont.data(), cont.length());
+    return ensure_z(cont.data(), static_cast<std::ptrdiff_t>(cont.length()));
 }
 
 //

From 557e6693b560ca491f285712081632bf4e93bda9 Mon Sep 17 00:00:00 2001
From: Vladislav Yaroslavlev <vladon@vladon.com>
Date: Thu, 12 Nov 2015 10:44:41 +0300
Subject: [PATCH 14/43] Add copy assignment operator to `strided_bounds`

`strided_bounds` defines copy constructor, but lacks copy assignment
operator
---
 include/span.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/span.h b/include/span.h
index 74da1aa..cb045cb 100644
--- a/include/span.h
+++ b/include/span.h
@@ -685,6 +685,8 @@ public:
 
     constexpr strided_bounds(const strided_bounds &) noexcept = default;
 
+    constexpr strided_bounds & operator=(const strided_bounds &) noexcept = default;
+
     constexpr strided_bounds(const value_type(&values)[rank], index_type strides)
         : m_extents(values), m_strides(std::move(strides))
     {}

From 995cfdf1cbd54a487008910ced5103d69e9e1acb Mon Sep 17 00:00:00 2001
From: Vladislav Yaroslavlev <vladon@vladon.com>
Date: Thu, 12 Nov 2015 10:46:21 +0300
Subject: [PATCH 15/43] Add copy assignment operator to `BoundsRanges`

`BoundsRanges` defines copy constructor, but lacks `=` operator
---
 include/span.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/span.h b/include/span.h
index cb045cb..adcded9 100644
--- a/include/span.h
+++ b/include/span.h
@@ -292,6 +292,7 @@ namespace details
         {}
         
         BoundsRanges (const BoundsRanges&) = default;
+        BoundsRanges& operator=(const BoundsRanges&) = default;
         BoundsRanges(const std::ptrdiff_t* const) { }
         BoundsRanges() = default;
 

From 550361cf46fecf99ecfcb8d6ce563f40ab25fc88 Mon Sep 17 00:00:00 2001
From: Olaf van der Spek <olafvdspek@gmail.com>
Date: Thu, 12 Nov 2015 10:23:56 +0100
Subject: [PATCH 16/43] Sort includes

---
 include/span.h | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/include/span.h b/include/span.h
index 74da1aa..b832e19 100644
--- a/include/span.h
+++ b/include/span.h
@@ -19,18 +19,18 @@
 #ifndef GSL_SPAN_H
 #define GSL_SPAN_H
 
-#include <new>
-#include <stdexcept>
+#include <algorithm>
+#include <array>
 #include <cstddef>
 #include <cstdint>
+#include <functional>
+#include <iterator>
 #include <limits>
+#include <new>
 #include <numeric>
+#include <stdexcept>
 #include <type_traits>
 #include <utility>
-#include <array>
-#include <iterator>
-#include <algorithm>
-#include <functional>
 #include "fail_fast.h"
 
 #ifdef _MSC_VER

From a998a9b33b3cbcc12595391de8d62a33eb14d290 Mon Sep 17 00:00:00 2001
From: Neil MacIntosh <neilmac@microsoft.com>
Date: Thu, 12 Nov 2015 18:57:23 -0800
Subject: [PATCH 17/43] Turned on Level 3 warnings for MSVC.

---
 include/span.h              | 1 +
 tests/CMakeLists.txt        | 1 +
 tests/span_tests.cpp        | 9 +++++++--
 tests/string_span_tests.cpp | 6 +++---
 4 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/include/span.h b/include/span.h
index 32cf828..f4a57d9 100644
--- a/include/span.h
+++ b/include/span.h
@@ -55,6 +55,7 @@
 // turn off some misguided warnings
 #pragma warning(push)
 #pragma warning(disable: 4351) // warns about newly introduced aggregate initializer behavior
+#pragma warning(disable: 4512) // warns that assignment op could not be generated
 
 #endif // _MSC_VER <= 1800
 
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 3435a7f..d49cf93 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -14,6 +14,7 @@ add_definitions(-DGSL_THROWS_FOR_TESTING)
 if(MSVC14 OR MSVC12) # has the support we need
     # remove unnecessary warnings about unchecked iterators
     add_definitions(-D_SCL_SECURE_NO_WARNINGS)
+    add_compile_options(/W4)
 else()
     include(CheckCXXCompilerFlag)
     CHECK_CXX_COMPILER_FLAG("-std=c++14" COMPILER_SUPPORTS_CXX14)
diff --git a/tests/span_tests.cpp b/tests/span_tests.cpp
index 4c21116..ae14f20 100644
--- a/tests/span_tests.cpp
+++ b/tests/span_tests.cpp
@@ -198,6 +198,7 @@ SUITE(span_tests)
 
 			string str = "ttttttttttttttt"; // size = 15
 			auto t = str.data();
+            (void)t;
 			auto av3 = as_span(str);
 			overloaded_func(av3.as_span(dim<>(1), dim<3>(), dim<5>()), 't');
 		}
@@ -223,12 +224,12 @@ SUITE(span_tests)
 		}
 	}
 	
-	template <class Bounds> void fn(const Bounds& b) { static_assert(Bounds::static_size == 60, "static bounds is wrong size"); }
+	template <class Bounds> void fn(const Bounds&) { static_assert(Bounds::static_size == 60, "static bounds is wrong size"); }
 	TEST (span_reshape_test)
 	{
 		int a[3][4][5];
 		auto av = as_span(a);
-        	fn(av.bounds());
+    	fn(av.bounds());
 		auto av2 = av.as_span(dim<60>());
 		auto av3 = av2.as_span(dim<3>(), dim<4>(), dim<5>());
 		auto av4 = av3.as_span(dim<4>(), dim<>(3), dim<5>());
@@ -755,6 +756,7 @@ SUITE(span_tests)
 			CHECK_THROW(empty_av.cbegin()[0], fail_fast);		
 			for (auto& v : empty_av)
 			{
+                (void)v;
 				CHECK(false);
 			}
 		}
@@ -767,6 +769,7 @@ SUITE(span_tests)
 			CHECK_THROW(empty_av.cbegin()[0], fail_fast); 
 			for (auto& v : empty_av)
 			{
+                (void)v;
 				CHECK(false);
 			}
 		}
@@ -782,6 +785,7 @@ SUITE(span_tests)
 
 			for (auto& v : empty_sav)
 			{
+                (void)v;
 				CHECK(false);
 			}
 		}
@@ -796,6 +800,7 @@ SUITE(span_tests)
 
 			for (auto& v : empty_sav)
 			{
+                (void)v;
 				CHECK(false);
 			}
 		}
diff --git a/tests/string_span_tests.cpp b/tests/string_span_tests.cpp
index ab48fcb..5d4681a 100644
--- a/tests/string_span_tests.cpp
+++ b/tests/string_span_tests.cpp
@@ -41,14 +41,14 @@ SUITE(string_span_tests)
     {
         std::string s = "Hello there world";
         cstring_span<> v = s;
-        CHECK(v.length() == s.length());
+        CHECK(v.length() == static_cast<cstring_span<>::size_type>(s.length()));
     }
 
     TEST(TestConstructFromStdVector)
     {
         std::vector<char> vec(5, 'h');
         string_span<> v = vec;
-        CHECK(v.length() == vec.size());
+        CHECK(v.length() == static_cast<string_span<>::size_type>(vec.size()));
     }
 
 	TEST(TestStackArrayConstruction)
@@ -114,7 +114,7 @@ SUITE(string_span_tests)
         char stack_string[] = "Hello";
         cstring_span<> v = ensure_z(stack_string);
         auto s2 = gsl::to_string(v);
-        CHECK(s2.length() == v.length());
+        CHECK(static_cast<cstring_span<>::size_type>(s2.length()) == v.length());
         CHECK(s2.length() == 5);
     }
 }

From fa056f67e8c0c3ef27df5da241c714cc0f45d71a Mon Sep 17 00:00:00 2001
From: Neil MacIntosh <neilmac@microsoft.com>
Date: Fri, 13 Nov 2015 03:27:53 +0000
Subject: [PATCH 18/43] Enabled -Wall for gcc and clang.

---
 tests/CMakeLists.txt        |  1 +
 tests/bounds_tests.cpp      | 10 +++++++---
 tests/notnull_tests.cpp     |  3 ++-
 tests/span_tests.cpp        | 33 +++++++++++++++++++++------------
 tests/string_span_tests.cpp |  1 +
 5 files changed, 32 insertions(+), 16 deletions(-)

diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index d49cf93..b16821b 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -26,6 +26,7 @@ else()
     else()
       message(STATUS "The compiler ${CMAKE_CXX_COMPILER} has no C++11 support. Please use a different C++ compiler.")
     endif()
+    add_compile_options(-Wall -Wno-missing-braces)
 endif()
 
 if (NOT EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/unittest-cpp)
diff --git a/tests/bounds_tests.cpp b/tests/bounds_tests.cpp
index 53c44d1..0665260 100644
--- a/tests/bounds_tests.cpp
+++ b/tests/bounds_tests.cpp
@@ -32,7 +32,9 @@ SUITE(bounds_test)
 	{
 		for (auto point : static_bounds<dynamic_range, 3, 4 > { 2 })
 		{
-			for (decltype(point)::size_type j = 0; j < decltype(point)::rank; j++)
+			for (decltype(point)::size_type j = 0;
+			     j < static_cast<decltype(point)::size_type>(decltype(point)::rank);
+			     j++)
 			{
 				use(j);
 				use(point[j]);
@@ -44,6 +46,7 @@ SUITE(bounds_test)
 	{
 		static_bounds<3, 4, 5> b;
 		auto a = b.slice();
+		(void)a;           
 		static_bounds<4, dynamic_range, 2> x{ 4 };
 		x.slice().slice();
 	}
@@ -53,7 +56,7 @@ SUITE(bounds_test)
 		static_bounds<4, dynamic_range, 2> bounds{ 3 };
 		
 		auto itr = bounds.begin();
-	
+		(void)itr;	
 #ifdef CONFIRM_COMPILATION_ERRORS
 		span<int, 4, dynamic_range, 2> av(nullptr, bounds);
 	
@@ -70,13 +73,14 @@ SUITE(bounds_test)
 	{
 		static_bounds<7, 4, 2> b1;
 		static_bounds<7, dynamic_range, 2> b2 = b1;
-	
+		(void)b2;	
 #ifdef CONFIRM_COMPILATION_ERRORS
 		static_bounds<7, dynamic_range, 1> b4 = b2; 
 #endif
 	
 		static_bounds<dynamic_range, dynamic_range, dynamic_range> b3 = b1;
 		static_bounds<7, 4, 2> b4 = b3; 
+		(void)b4;
 
 		static_bounds<dynamic_range> b11;
 	
diff --git a/tests/notnull_tests.cpp b/tests/notnull_tests.cpp
index a9624b8..67b478a 100644
--- a/tests/notnull_tests.cpp
+++ b/tests/notnull_tests.cpp
@@ -69,7 +69,8 @@ SUITE(NotNullTests)
 	MyDerived derived;
 	Unrelated unrelated;
 	not_null<Unrelated*> u = &unrelated;
-        not_null<MyDerived*> p = &derived;
+        (void)u;
+	not_null<MyDerived*> p = &derived;
         not_null<MyBase*> q = &base;
 	q = p; // allowed with heterogeneous copy ctor
         CHECK(q == p);
diff --git a/tests/span_tests.cpp b/tests/span_tests.cpp
index ae14f20..6a67b02 100644
--- a/tests/span_tests.cpp
+++ b/tests/span_tests.cpp
@@ -27,7 +27,6 @@ using namespace gsl;
 
 namespace 
 {
-	void use(int&) {}
 	struct BaseClass {};
 	struct DerivedClass : BaseClass {};
 }
@@ -82,6 +81,7 @@ SUITE(span_tests)
 		span<BaseClass> avb = avd;
 #endif
 		span<const DerivedClass> avcd = avd;
+		(void)avcd;
 	}
 
 	TEST(boundary_checks)
@@ -214,9 +214,11 @@ SUITE(span_tests)
 
 			const std::array<double, 3> arr = {0.0, 0.0, 0.0};
 			auto cv = as_span(arr);
+			(void)cv;
 
 			vector<float> vec(3);
 			auto dv = as_span(vec);
+			(void)dv;
 			
 #ifdef CONFIRM_COMPILATION_ERRORS
 			auto dv2 = as_span(std::move(vec));
@@ -262,6 +264,7 @@ SUITE(span_tests)
 		auto av = as_span(a);
 		auto sub = av.section({15, 0, 0}, gsl::index<3>{2, 2, 2});
 		auto subsub = sub.section({1, 0, 0}, gsl::index<3>{1, 1, 1});
+		(void)subsub;
 	}
 
 	TEST(span_section)
@@ -1417,7 +1420,7 @@ SUITE(span_tests)
 		CHECK_THROW(av1[10][3][4], fail_fast);
 
 		span<const double, dynamic_range, 6, 4> av2 = av1.as_span(dim<>(5), dim<6>(), dim<4>());
-		
+		(void)av2;
 	}
 
 	TEST(span_sub)
@@ -1429,7 +1432,7 @@ SUITE(span_tests)
 			CHECK((av.sub<2,2>().bounds() == static_bounds<2>()));
 			CHECK((av.sub<2,2>().length() == 2));
 			CHECK(av.sub(2,2).length() == 2);
-            CHECK(av.sub(2,3).length() == 3);
+            		CHECK(av.sub(2,3).length() == 3);
 		}
 
 
@@ -1445,16 +1448,16 @@ SUITE(span_tests)
 			CHECK((av.sub<0,5>().bounds() == static_bounds<5>()));
 			CHECK((av.sub<0,5>().length() == 5));
 			CHECK(av.sub(0,5).length() == 5);
-            CHECK_THROW(av.sub(0,6).length(), fail_fast);
-            CHECK_THROW(av.sub(1,5).length(), fail_fast);
+		        CHECK_THROW(av.sub(0,6).length(), fail_fast);
+		        CHECK_THROW(av.sub(1,5).length(), fail_fast);
 		}
 
 		{
 			span<int, 5> av = arr;
 			CHECK((av.sub<5,0>().bounds() == static_bounds<0>()));
-            CHECK((av.sub<5, 0>().length() == 0));
-            CHECK(av.sub(5,0).length() == 0);
-            CHECK_THROW(av.sub(6,0).length(), fail_fast);
+            		CHECK((av.sub<5, 0>().length() == 0));
+            		CHECK(av.sub(5,0).length() == 0);
+            		CHECK_THROW(av.sub(6,0).length(), fail_fast);
 		}
 
 		{
@@ -1462,7 +1465,7 @@ SUITE(span_tests)
 			CHECK((av.sub<0,0>().bounds() == static_bounds<0>()));
 			CHECK((av.sub<0,0>().length() == 0));
 			CHECK(av.sub(0,0).length() == 0);
-            CHECK_THROW((av.sub<1,0>().length()), fail_fast);
+            		CHECK_THROW((av.sub<1,0>().length()), fail_fast);
 		}
 
         {
@@ -1559,9 +1562,11 @@ SUITE(span_tests)
 		// converting to dynamic_range a_v is always ok
 		{
 			span<int, dynamic_range> av = av4;
+			(void)av;
 		}
 		{
 			span<int, dynamic_range> av = arr;
+			(void)av;
 		}
 
 		// initialization or assignment to static span that REDUCES size is NOT ok
@@ -1577,6 +1582,7 @@ SUITE(span_tests)
 		{
 			span<int, dynamic_range> av = arr;
 			span<int, 2> av2 = av;
+			(void)av2;
 		}
 
 #ifdef CONFIRM_COMPILATION_ERRORS
@@ -1588,7 +1594,7 @@ SUITE(span_tests)
 
 		{
 			span<int, dynamic_range> av = arr;
-			auto f = [&]() {span<int, 2, 1> av2 = av.as_span(dim<>(2), dim<>(2));};
+			auto f = [&]() {span<int, 2, 1> av2 = av.as_span(dim<>(2), dim<>(2)); (void)av2; };
 			CHECK_THROW(f(), fail_fast);
 		}
 
@@ -1597,15 +1603,18 @@ SUITE(span_tests)
 		// you can convert statically
 		{
 			span<int, 2> av2 = {arr, 2};
+			(void)av2;
 		}
 		{
 			span<int, 1> av2 = av4.first<1>();
+			(void)av2;
 		}
 			
 		// ...or dynamically
 		{
 			// NB: implicit conversion to span<int,2> from span<int,dynamic_range>
 			span<int, 1> av2 = av4.first(1); 
+			(void)av2;
 		}
 
 		// initialization or assignment to static span that requires size INCREASE is not ok.
@@ -1621,13 +1630,13 @@ SUITE(span_tests)
 		}
 #endif
 		{
-			auto f = [&]() {span<int, 4> av4 = {arr2, 2};};
+			auto f = [&]() {span<int, 4> av4 = {arr2, 2}; (void)av4; };
 			CHECK_THROW(f(), fail_fast);
 		}
 
 		// this should fail - we are trying to assign a small dynamic a_v to a fixed_size larger one
 		span<int, dynamic_range> av = arr2;
-		auto f = [&](){ span<int, 4> av2 = av; };
+		auto f = [&](){ span<int, 4> av2 = av; (void)av2; };
 		CHECK_THROW(f(), fail_fast);
 	}
 
diff --git a/tests/string_span_tests.cpp b/tests/string_span_tests.cpp
index 5d4681a..efdf0ff 100644
--- a/tests/string_span_tests.cpp
+++ b/tests/string_span_tests.cpp
@@ -100,6 +100,7 @@ SUITE(string_span_tests)
     {
         char stack_string[] = "Hello";
         cstring_span<> v = ensure_z(stack_string);
+	(void)v;
 #ifdef CONFIRM_COMPILATION_ERRORS
         string_span<> v2 = v;
         string_span<> v3 = "Hello";

From b9565e50ce9d01173243dfcda3e108e5b9a8e75e Mon Sep 17 00:00:00 2001
From: Neil MacIntosh <neilmac@microsoft.com>
Date: Thu, 12 Nov 2015 19:36:34 -0800
Subject: [PATCH 19/43] Update CMakeLists.txt

---
 tests/CMakeLists.txt | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index b16821b..5529cda 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -20,13 +20,12 @@ else()
     CHECK_CXX_COMPILER_FLAG("-std=c++14" COMPILER_SUPPORTS_CXX14)
     CHECK_CXX_COMPILER_FLAG("-std=c++11" COMPILER_SUPPORTS_CXX11)
     if(COMPILER_SUPPORTS_CXX14)
-    	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++14")
+    	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++14 -Wall -Wno-missing-braces")
     elseif(COMPILER_SUPPORTS_CXX11)
-    	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
+    	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -Wall -Wno-missing-braces")
     else()
       message(STATUS "The compiler ${CMAKE_CXX_COMPILER} has no C++11 support. Please use a different C++ compiler.")
     endif()
-    add_compile_options(-Wall -Wno-missing-braces)
 endif()
 
 if (NOT EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/unittest-cpp)

From 8aa42487225a537ddedac668ec14e179bb481935 Mon Sep 17 00:00:00 2001
From: Anna Gringauze <annagrin@microsoft.com>
Date: Wed, 11 Nov 2015 12:41:11 -0800
Subject: [PATCH 20/43] Removing basic_span base class from span

---
 include/span.h       | 328 ++++++++++++++++++++++++++++++-------------
 tests/span_tests.cpp |  19 +--
 2 files changed, 239 insertions(+), 108 deletions(-)

diff --git a/include/span.h b/include/span.h
index f4a57d9..cbc766b 100644
--- a/include/span.h
+++ b/include/span.h
@@ -111,19 +111,19 @@ public:
         std::copy(values, values + Rank, elems);
     }
 
-#ifdef GSL_MSVC_HAS_VARIADIC_CTOR_BUG           
-    template<typename T, typename... Ts, 
-        typename = std::enable_if_t<((sizeof...(Ts) + 1) == Rank) && 
-        std::is_integral<T>::value && 
-        details::are_integral<Ts...>::value>> 
-    constexpr index(T t, Ts... ds) : index({ static_cast<value_type>(t), static_cast<value_type>(ds)... }) 
-    {} 
-#else 
-    template<typename... Ts, 
-        typename = std::enable_if_t<(sizeof...(Ts) == Rank) && details::are_integral<Ts...>::value>> 
-    constexpr index(Ts... ds) noexcept : elems{ static_cast<value_type>(ds)... } 
-    {} 
-#endif 
+#ifdef GSL_MSVC_HAS_VARIADIC_CTOR_BUG
+    template<typename T, typename... Ts,
+        typename = std::enable_if_t<((sizeof...(Ts) + 1) == Rank) &&
+        std::is_integral<T>::value &&
+        details::are_integral<Ts...>::value>>
+    constexpr index(T t, Ts... ds) : index({ static_cast<value_type>(t), static_cast<value_type>(ds)... })
+    {}
+#else
+    template<typename... Ts,
+        typename = std::enable_if_t<(sizeof...(Ts) == Rank) && details::are_integral<Ts...>::value>>
+    constexpr index(Ts... ds) noexcept : elems{ static_cast<value_type>(ds)... }
+    {}
+#endif
 
     constexpr index(const index& other) noexcept = default;
 
@@ -1039,9 +1039,9 @@ namespace details
 
 } // namespace details
 
-template <typename ArrayView>
+template <typename Span>
 class contiguous_span_iterator;
-template <typename ArrayView>
+template <typename Span>
 class general_span_iterator;
 enum class byte : std::uint8_t {};
 
@@ -1235,21 +1235,21 @@ class strided_span;
 namespace details
 {
     template <typename T, typename = std::true_type>
-    struct ArrayViewTypeTraits
+    struct SpanTypeTraits
     {
         using value_type = T;
         using size_type = size_t;
     };
 
     template <typename Traits>
-    struct ArrayViewTypeTraits<Traits, typename std::is_reference<typename Traits::span_traits &>::type>
+    struct SpanTypeTraits<Traits, typename std::is_reference<typename Traits::span_traits &>::type>
     {
         using value_type = typename Traits::span_traits::value_type;
         using size_type = typename Traits::span_traits::size_type;
     };
 
     template <typename T, std::ptrdiff_t... Ranks>
-    struct ArrayViewArrayTraits {
+    struct SpanArrayTraits {
         using type = span<T, Ranks...>;
         using value_type = T;
         using bounds_type = static_bounds<Ranks...>;
@@ -1257,7 +1257,7 @@ namespace details
         using reference = T&;
     };
     template <typename T, std::ptrdiff_t N, std::ptrdiff_t... Ranks>
-    struct ArrayViewArrayTraits<T[N], Ranks...> : ArrayViewArrayTraits<T, Ranks..., N> {};
+    struct SpanArrayTraits<T[N], Ranks...> : SpanArrayTraits<T, Ranks..., N> {};
 
     template <typename BoundsType>
     BoundsType newBoundsHelperImpl(std::ptrdiff_t totalSize, std::true_type) // dynamic size
@@ -1322,108 +1322,122 @@ namespace details
 
 
 template <typename ValueType, std::ptrdiff_t FirstDimension, std::ptrdiff_t... RestDimensions>
-class span : public basic_span <ValueType, static_bounds <FirstDimension, RestDimensions...>>
+class span
 {
-    template <typename ValueType2, std::ptrdiff_t FirstDimension2,
-              std::ptrdiff_t... RestDimensions2>
+    template <typename ValueType2, std::ptrdiff_t FirstDimension2, std::ptrdiff_t... RestDimensions2>
     friend class span;
 
-    using Base = basic_span<ValueType, static_bounds<FirstDimension, RestDimensions...>>;
+public:
+    using BoundsType = static_bounds<FirstDimension, RestDimensions...>;
+    static const size_t rank = BoundsType::rank;
+    using bounds_type = BoundsType;
+    using size_type = typename bounds_type::size_type;
+    using index_type = typename bounds_type::index_type;
+    using value_type = ValueType;
+    using const_value_type = std::add_const_t<value_type>;
+    using pointer = ValueType*;
+    using reference = ValueType&;
+    using iterator = contiguous_span_iterator<span>;
+    using const_span = span<const_value_type, FirstDimension, RestDimensions...>;
+    using const_iterator = contiguous_span_iterator<const_span>;
+    using reverse_iterator = std::reverse_iterator<iterator>;
+    using const_reverse_iterator = std::reverse_iterator<const_iterator>;
+    using sliced_type = std::conditional_t<rank == 1, value_type, span<value_type, RestDimensions...>>;
+
+private:
+    pointer m_pdata;
+    bounds_type m_bounds;
+
+    friend iterator;
+    friend const_iterator;
 
 public:
-    using typename Base::bounds_type;
-    using typename Base::size_type;
-    using typename Base::pointer;
-    using typename Base::value_type;
-    using typename Base::index_type;
-    using typename Base::iterator;
-    using typename Base::const_iterator;
-    using typename Base::reference;
-    using Base::rank;
 
-public:
-    // basic
-    constexpr span(pointer ptr, size_type size) : Base(ptr, bounds_type{ size })
+    constexpr span(pointer data, bounds_type bound) noexcept
+        : m_pdata(data), m_bounds(std::move(bound))
+    {
+        fail_fast_assert((m_bounds.size() > 0 && data != nullptr) || m_bounds.size() == 0);
+    }
+
+    constexpr span(pointer ptr, size_type size) : span(ptr, bounds_type{ size })
     {}
 
-    constexpr span(pointer ptr, bounds_type bounds) : Base(ptr, std::move(bounds))
+    constexpr span(std::nullptr_t) : span(nullptr, bounds_type{})
     {}
 
-    constexpr span(std::nullptr_t) : Base(nullptr, bounds_type{})
-    {}
-
-    constexpr span(std::nullptr_t, size_type size) : Base(nullptr, bounds_type{})
+    constexpr span(std::nullptr_t, size_type size) : span(nullptr, bounds_type{})
     {
         fail_fast_assert(size == 0);
     }
 
     // default
     template <std::ptrdiff_t DynamicRank = bounds_type::dynamic_rank, typename = std::enable_if_t<DynamicRank != 0>>
-    constexpr span() : Base(nullptr, bounds_type())
+    constexpr span() : span(nullptr, bounds_type())
     {}
 
     // from n-dimensions dynamic array (e.g. new int[m][4]) (precedence will be lower than the 1-dimension pointer)
-    template <typename T, typename Helper = details::ArrayViewArrayTraits<T, dynamic_range>
-        /*typename Dummy = std::enable_if_t<std::is_convertible<Helper::value_type (*)[], typename Base::value_type (*)[]>::value>*/>
-    constexpr span(T* const& data, size_type size) : Base(data, typename Helper::bounds_type{size})
+    template <typename T, typename Helper = details::SpanArrayTraits<T, dynamic_range>
+        /*typename Dummy = std::enable_if_t<std::is_convertible<Helper::value_type (*)[], value_type (*)[]>::value>*/
+    >
+    constexpr span(T* const& data, size_type size) : span(data, typename Helper::bounds_type{size})
     {}
 
     // from n-dimensions static array
-    template <typename T, size_t N, typename Helper = details::ArrayViewArrayTraits<T, N>,
-        typename = std::enable_if_t<std::is_convertible<typename Helper::value_type(*)[], typename Base::value_type(*)[]>::value>>
-    constexpr span (T (&arr)[N]) : Base(arr, typename Helper::bounds_type())
+    template <typename T, size_t N, typename Helper = details::SpanArrayTraits<T, N>,
+        typename = std::enable_if_t<std::is_convertible<typename Helper::value_type(*)[], value_type(*)[]>::value>
+    >
+    constexpr span (T (&arr)[N]) : span(arr, typename Helper::bounds_type())
     {}
 
     // from n-dimensions static array with size
-    template <typename T, size_t N, typename Helper = details::ArrayViewArrayTraits<T, N>,
-        typename = std::enable_if_t<std::is_convertible<typename Helper::value_type(*)[], typename Base::value_type(*)[]>::value>
+    template <typename T, size_t N, typename Helper = details::SpanArrayTraits<T, N>,
+        typename = std::enable_if_t<std::is_convertible<typename Helper::value_type(*)[], value_type(*)[]>::value>
     >
-    constexpr span(T(&arr)[N], size_type size) : Base(arr, typename Helper::bounds_type{size})
+    constexpr span(T(&arr)[N], size_type size) : span(arr, typename Helper::bounds_type{size})
     {
         fail_fast_assert(size <= N);
     }
 
     // from std array
     template <size_t N, 
-       typename Dummy = std::enable_if_t<std::is_convertible<static_bounds<N>, typename Base::bounds_type>::value>
+       typename Dummy = std::enable_if_t<std::is_convertible<static_bounds<N>, bounds_type>::value>
     >
-    constexpr span (std::array<std::remove_const_t<value_type>, N> & arr) : Base(arr.data(), static_bounds<N>())
+    constexpr span (std::array<std::remove_const_t<value_type>, N> & arr) : span(arr.data(), static_bounds<N>())
     {}
 
     template <size_t N,
-        typename Dummy = std::enable_if_t<std::is_convertible<static_bounds<N>, typename Base::bounds_type>::value
+        typename Dummy = std::enable_if_t<std::is_convertible<static_bounds<N>, bounds_type>::value
         && std::is_const<value_type>::value>
     >
-    constexpr span (const std::array<std::remove_const_t<value_type>, N> & arr) : Base(arr.data(), static_bounds<N>())
+    constexpr span (const std::array<std::remove_const_t<value_type>, N> & arr) : span(arr.data(), static_bounds<N>())
     {}
     
     // from begin, end pointers. We don't provide iterator pair since no way to guarantee the contiguity 
     template <typename Ptr,
         typename Dummy = std::enable_if_t<std::is_convertible<Ptr, pointer>::value
-        && details::LessThan<Base::bounds_type::dynamic_rank, 2>::value>
+        && details::LessThan<bounds_type::dynamic_rank, 2>::value>
     > // remove literal 0 case
-    constexpr span (pointer begin, Ptr end) : Base(begin, details::newBoundsHelper<typename Base::bounds_type>(static_cast<pointer>(end) - begin))
+    constexpr span (pointer begin, Ptr end) : span(begin, details::newBoundsHelper<bounds_type>(static_cast<pointer>(end) - begin))
     {}
 
     // from containers. It must has .size() and .data() two function signatures
     template <typename Cont, typename DataType = typename Cont::value_type,
         typename Dummy = std::enable_if_t<!details::is_span<Cont>::value
-        && std::is_convertible<DataType (*)[], typename Base::value_type (*)[]>::value
+        && std::is_convertible<DataType (*)[], value_type (*)[]>::value
         && std::is_same<std::decay_t<decltype(std::declval<Cont>().size(), *std::declval<Cont>().data())>, DataType>::value>
     >
-    constexpr span (Cont& cont) : Base(static_cast<pointer>(cont.data()), details::newBoundsHelper<typename Base::bounds_type>(cont.size()))
+    constexpr span (Cont& cont) : span(static_cast<pointer>(cont.data()), details::newBoundsHelper<bounds_type>(cont.size()))
     {}
 
     constexpr span(const span &) = default;
 
     // convertible
     template <typename OtherValueType, std::ptrdiff_t... OtherDimensions,
-        typename BaseType = basic_span<ValueType, static_bounds<FirstDimension, RestDimensions...>>,
-        typename OtherBaseType = basic_span<OtherValueType, static_bounds<OtherDimensions...>>,
-        typename Dummy = std::enable_if_t<std::is_convertible<OtherBaseType, BaseType>::value>
+        typename OtherBounds = static_bounds<OtherDimensions...>,
+        typename Dummy = std::enable_if_t<std::is_convertible<OtherValueType, ValueType>::value && std::is_convertible<OtherBounds, bounds_type>::value>
     >
-    constexpr span(const span<OtherValueType, OtherDimensions...> &av)
-        : Base(static_cast<const typename span<OtherValueType, OtherDimensions...>::Base&>(av))
+    constexpr span(const span<OtherValueType, OtherDimensions...>& other)
+        : m_pdata(other.m_pdata), m_bounds(other.m_bounds)
     {}
 
     // reshape
@@ -1454,18 +1468,18 @@ public:
 
     // from bytes array
     template<typename U, bool IsByte = std::is_same<value_type, const byte>::value, typename = std::enable_if_t<IsByte && sizeof...(RestDimensions) == 0>>
-    constexpr auto as_span() const noexcept -> span<const U, (Base::bounds_type::static_size != dynamic_range ? static_cast<std::ptrdiff_t>(static_cast<size_t>(Base::bounds_type::static_size) / sizeof(U)) : dynamic_range)>
+    constexpr auto as_span() const noexcept -> span<const U, (bounds_type::static_size != dynamic_range ? static_cast<std::ptrdiff_t>(static_cast<size_t>(bounds_type::static_size) / sizeof(U)) : dynamic_range)>
     {
-        static_assert(std::is_standard_layout<U>::value && (Base::bounds_type::static_size == dynamic_range || Base::bounds_type::static_size % static_cast<size_type>(sizeof(U)) == 0),
+        static_assert(std::is_standard_layout<U>::value && (bounds_type::static_size == dynamic_range || bounds_type::static_size % static_cast<size_type>(sizeof(U)) == 0),
             "Target type must be standard layout and its size must match the byte array size");
         fail_fast_assert((this->bytes() % sizeof(U)) == 0 && (this->bytes() / sizeof(U)) < PTRDIFF_MAX);
         return { reinterpret_cast<const U*>(this->data()), this->bytes() / static_cast<size_type>(sizeof(U)) };
     }
 
     template<typename U, bool IsByte = std::is_same<value_type, byte>::value, typename = std::enable_if_t<IsByte && sizeof...(RestDimensions) == 0>>
-    constexpr auto as_span() const noexcept -> span<U, (Base::bounds_type::static_size != dynamic_range ? static_cast<ptrdiff_t>(static_cast<size_t>(Base::bounds_type::static_size) / sizeof(U)) : dynamic_range)>
+    constexpr auto as_span() const noexcept -> span<U, (bounds_type::static_size != dynamic_range ? static_cast<ptrdiff_t>(static_cast<size_t>(bounds_type::static_size) / sizeof(U)) : dynamic_range)>
     {
-        static_assert(std::is_standard_layout<U>::value && (Base::bounds_type::static_size == dynamic_range || Base::bounds_type::static_size % static_cast<size_t>(sizeof(U)) == 0),
+        static_assert(std::is_standard_layout<U>::value && (bounds_type::static_size == dynamic_range || bounds_type::static_size % static_cast<size_t>(sizeof(U)) == 0),
             "Target type must be standard layout and its size must match the byte array size");
         fail_fast_assert((this->bytes() % sizeof(U)) == 0);
         return { reinterpret_cast<U*>(this->data()), this->bytes() / static_cast<size_type>(sizeof(U)) };
@@ -1539,27 +1553,143 @@ public:
     constexpr strided_span<ValueType, rank> section(index_type origin, index_type extents) const
     {
         size_type size = this->bounds().total_size() - this->bounds().linearize(origin);
-        return{ &this->operator[](origin), size, strided_bounds<rank> {extents, details::make_stride(Base::bounds())} };
+        return{ &this->operator[](origin), size, strided_bounds<rank> {extents, details::make_stride(bounds())} };
     }
     
-        constexpr reference operator[](const index_type& idx) const
+    constexpr reference operator[](const index_type& idx) const
     {
-        return Base::operator[](idx);
+        return m_pdata[m_bounds.linearize(idx)];
     }
     
-        template <bool Enabled = (rank > 1), typename Dummy = std::enable_if_t<Enabled>>
-    constexpr span<ValueType, RestDimensions...> operator[](size_type idx) const
+    template <bool Enabled = (rank > 1), typename Ret = std::enable_if_t<Enabled, sliced_type>>
+    constexpr Ret operator[](size_type idx) const
     {
-        auto ret = Base::operator[](idx);
-        return{ ret.data(), ret.bounds() };
+        fail_fast_assert(idx < m_bounds.size(), "index is out of bounds of the array");
+        const size_type ridx = idx * m_bounds.stride();
+
+        fail_fast_assert(ridx < m_bounds.total_size(), "index is out of bounds of the underlying data");
+        return Ret{ m_pdata + ridx, m_bounds.slice() };
     }
 
-    using Base::operator==;
-    using Base::operator!=;
-    using Base::operator<;
-    using Base::operator<=;
-    using Base::operator>;
-    using Base::operator>=;
+    constexpr bounds_type bounds() const noexcept
+    {
+        return m_bounds;
+    }
+
+    template <size_t Dim = 0>
+    constexpr size_type extent() const noexcept
+    {
+        static_assert(Dim < rank, "dimension should be less than rank (dimension count starts from 0)");
+        return m_bounds.template extent<Dim>();
+    }
+
+    constexpr size_type size() const noexcept
+    {
+        return m_bounds.size();
+    }
+
+    constexpr pointer data() const noexcept
+    {
+        return m_pdata;
+    }
+
+    constexpr operator bool() const noexcept
+    {
+        return m_pdata != nullptr;
+    }
+
+    constexpr iterator begin() const
+    {
+        return iterator{ this, true };
+    }
+
+    constexpr iterator end() const
+    {
+        return iterator{ this, false };
+    }
+
+    constexpr const_iterator cbegin() const
+    {
+        return const_iterator{ reinterpret_cast<const const_span*>(this), true };
+    }
+
+    constexpr const_iterator cend() const
+    {
+        return const_iterator{ reinterpret_cast<const const_span*>(this), false };
+    }
+
+    constexpr reverse_iterator rbegin() const
+    {
+        return reverse_iterator{ end() };
+    }
+
+    constexpr reverse_iterator rend() const
+    {
+        return reverse_iterator{ begin() };
+    }
+
+    constexpr const_reverse_iterator crbegin() const
+    {
+        return const_reverse_iterator{ cend() };
+    }
+
+    constexpr const_reverse_iterator crend() const
+    {
+        return const_reverse_iterator{ cbegin() };
+    }
+
+    template <typename OtherValueType, std::ptrdiff_t... OtherDimensions, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
+    constexpr bool operator== (const span<OtherValueType, OtherDimensions...> & other) const noexcept
+    {
+        return m_bounds.size() == other.m_bounds.size() &&
+            (m_pdata == other.m_pdata || std::equal(this->begin(), this->end(), other.begin()));
+    }
+
+    template <typename OtherValueType, std::ptrdiff_t... OtherDimensions, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
+    constexpr bool operator!= (const span<OtherValueType, OtherDimensions...> & other) const noexcept
+    {
+        return !(*this == other);
+    }
+
+    template <typename OtherValueType, std::ptrdiff_t... OtherDimensions, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
+    constexpr bool operator< (const span<OtherValueType, OtherDimensions...> & other) const noexcept
+    {
+        return std::lexicographical_compare(this->begin(), this->end(), other.begin(), other.end());
+    }
+
+    template <typename OtherValueType, std::ptrdiff_t... OtherDimensions, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
+    constexpr bool operator<= (const span<OtherValueType, OtherDimensions...> & other) const noexcept
+    {
+        return !(other < *this);
+    }
+
+    template <typename OtherValueType, std::ptrdiff_t... OtherDimensions, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
+    constexpr bool operator> (const span<OtherValueType, OtherDimensions...> & other) const noexcept
+    {
+        return (other < *this);
+    }
+
+    template <typename OtherValueType, std::ptrdiff_t... OtherDimensions, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
+    constexpr bool operator>= (const span<OtherValueType, OtherDimensions...> & other) const noexcept
+    {
+        return !(*this < other);
+    }
+
+private:
+
+    template <typename T>
+    constexpr span(T *data, std::enable_if_t<std::is_same<value_type, std::remove_all_extents_t<T>>::value, bounds_type> bound) noexcept
+        : m_pdata(reinterpret_cast<pointer>(data)), m_bounds(std::move(bound))
+    {
+        fail_fast_assert((m_bounds.size() > 0 && data != nullptr) || m_bounds.size() == 0);
+    }
+
+    template <std::ptrdiff_t... OtherDimensions>
+    constexpr span<value_type, OtherDimensions...> as_span(const static_bounds<OtherDimensions...> &bounds)
+    {
+        details::verifyBoundsReshape(m_bounds, bounds);
+        return{ m_pdata, bounds };
+    }
 };
 
 template <typename T, std::ptrdiff_t... Dimensions>
@@ -1569,13 +1699,13 @@ constexpr auto as_span(T* const& ptr, dim<Dimensions>... args) -> span<std::remo
 }
 
 template <typename T>
-constexpr auto as_span (T* arr, std::ptrdiff_t len) -> typename details::ArrayViewArrayTraits<T, dynamic_range>::type
+constexpr auto as_span (T* arr, std::ptrdiff_t len) -> typename details::SpanArrayTraits<T, dynamic_range>::type
 {
     return {reinterpret_cast<std::remove_all_extents_t<T>*>(arr), len};
 }
 
 template <typename T, size_t N>
-constexpr auto as_span (T (&arr)[N]) -> typename details::ArrayViewArrayTraits<T, N>::type
+constexpr auto as_span (T (&arr)[N]) -> typename details::SpanArrayTraits<T, N>::type
 {
     return {arr};
 }
@@ -1725,26 +1855,26 @@ private:
     }
 };
 
-template <typename ArrayView>
-class contiguous_span_iterator : public std::iterator<std::random_access_iterator_tag, typename ArrayView::value_type>
+template <class Span>
+class contiguous_span_iterator : public std::iterator<std::random_access_iterator_tag, typename Span::value_type>
 {
-    using Base = std::iterator<std::random_access_iterator_tag, typename ArrayView::value_type>;
+    using Base = std::iterator<std::random_access_iterator_tag, typename Span::value_type>;
 public:
     using typename Base::reference;
     using typename Base::pointer;
     using typename Base::difference_type;
 
 private:
-    template <typename ValueType, typename Bounds>
-    friend class basic_span;
+    template <typename ValueType, std::ptrdiff_t FirstDimension, std::ptrdiff_t... RestDimensions>
+    friend class span;
 
     pointer m_pdata;
-    const ArrayView * m_validator;
+    const Span* m_validator;
     void validateThis() const
     {
         fail_fast_assert(m_pdata >= m_validator->m_pdata && m_pdata < m_validator->m_pdata + m_validator->size(), "iterator is out of range of the array");
     }
-    contiguous_span_iterator (const ArrayView *container, bool isbegin) :
+    contiguous_span_iterator (const Span* container, bool isbegin) :
         m_pdata(isbegin ? container->m_pdata : container->m_pdata + container->size()), m_validator(container) {}
 public:
     reference operator*() const noexcept
@@ -1840,16 +1970,16 @@ public:
     }
 };
 
-template <typename ArrayView>
-contiguous_span_iterator<ArrayView> operator+(typename contiguous_span_iterator<ArrayView>::difference_type n, const contiguous_span_iterator<ArrayView>& rhs) noexcept
+template <typename Span>
+contiguous_span_iterator<Span> operator+(typename contiguous_span_iterator<Span>::difference_type n, const contiguous_span_iterator<Span>& rhs) noexcept
 {
     return rhs + n;
 }
 
-template <typename ArrayView>
-class general_span_iterator : public std::iterator<std::random_access_iterator_tag, typename ArrayView::value_type>
+template <typename Span>
+class general_span_iterator : public std::iterator<std::random_access_iterator_tag, typename Span::value_type>
 {
-    using Base = std::iterator<std::random_access_iterator_tag, typename ArrayView::value_type>;
+    using Base = std::iterator<std::random_access_iterator_tag, typename Span::value_type>;
 public:
     using typename Base::reference;
     using typename Base::pointer;
@@ -1859,9 +1989,9 @@ private:
     template <typename ValueType, typename Bounds>
     friend class basic_span;
     
-    const ArrayView * m_container;
-    typename ArrayView::bounds_type::iterator m_itr;
-    general_span_iterator(const ArrayView *container, bool isbegin) :
+    const Span * m_container;
+    typename Span::bounds_type::iterator m_itr;
+    general_span_iterator(const Span *container, bool isbegin) :
         m_container(container), m_itr(isbegin ? m_container->bounds().begin() : m_container->bounds().end())
     {}
 public:
@@ -1956,8 +2086,8 @@ public:
     }
 };
 
-template <typename ArrayView>
-general_span_iterator<ArrayView> operator+(typename general_span_iterator<ArrayView>::difference_type n, const general_span_iterator<ArrayView>& rhs) noexcept
+template <typename Span>
+general_span_iterator<Span> operator+(typename general_span_iterator<Span>::difference_type n, const general_span_iterator<Span>& rhs) noexcept
 {
     return rhs + n;
 }
diff --git a/tests/span_tests.cpp b/tests/span_tests.cpp
index 6a67b02..ecb2c4e 100644
--- a/tests/span_tests.cpp
+++ b/tests/span_tests.cpp
@@ -323,28 +323,29 @@ SUITE(span_tests)
 				CHECK(sav[1] == 2);
 
 #if _MSC_VER > 1800
-				strided_span<const int, 1> sav_c{ {src}, {2, 1} };
-#else                
+				//strided_span<const int, 1> sav_c{ {src}, {2, 1} };
 				strided_span<const int, 1> sav_c{ span<const int>{src}, strided_bounds<1>{2, 1} };
-#endif                
+#else
+				strided_span<const int, 1> sav_c{ span<const int>{src}, strided_bounds<1>{2, 1} };
+#endif
 				CHECK(sav_c.bounds().index_bounds() == index<1>{ 2 });
 				CHECK(sav_c.bounds().strides() == index<1>{ 1 });
 				CHECK(sav_c[1] == 2);
 
 #if _MSC_VER > 1800
 				strided_span<volatile int, 1> sav_v{ {src}, {2, 1} };
-#else                
+#else
 				strided_span<volatile int, 1> sav_v{ span<volatile int>{src}, strided_bounds<1>{2, 1} };
-#endif                
+#endif
 				CHECK(sav_v.bounds().index_bounds() == index<1>{ 2 });
 				CHECK(sav_v.bounds().strides() == index<1>{ 1 });
 				CHECK(sav_v[1] == 2);
 
 #if _MSC_VER > 1800
 				strided_span<const volatile int, 1> sav_cv{ {src}, {2, 1} };
-#else                
+#else
 				strided_span<const volatile int, 1> sav_cv{ span<const volatile int>{src}, strided_bounds<1>{2, 1} };
-#endif                
+#endif
 				CHECK(sav_cv.bounds().index_bounds() == index<1>{ 2 });
 				CHECK(sav_cv.bounds().strides() == index<1>{ 1 });
 				CHECK(sav_cv[1] == 2);
@@ -363,7 +364,7 @@ SUITE(span_tests)
 				strided_span<const volatile int, 1> sav_cv{ {src}, {2, 1} };
 #else
 				strided_span<const volatile int, 1> sav_cv{ span<const volatile int>{src}, strided_bounds<1>{2, 1} };
-#endif                
+#endif
 				
 				CHECK(sav_cv.bounds().index_bounds() == index<1>{ 2 });
 				CHECK(sav_cv.bounds().strides() == index<1>{ 1 });
@@ -383,7 +384,7 @@ SUITE(span_tests)
 				strided_span<const volatile int, 1> sav_cv{ {src}, {2, 1} };
 #else
 				strided_span<const volatile int, 1> sav_cv{ span<const volatile int>{src}, strided_bounds<1>{2, 1} };
-#endif                
+#endif
 				CHECK(sav_cv.bounds().index_bounds() == index<1>{ 2 });
 				CHECK(sav_cv.bounds().strides() == index<1>{ 1 });
 				CHECK(sav_cv[1] == 2);

From f510025109a75035ba9c99616ab5232f86c0b51d Mon Sep 17 00:00:00 2001
From: Anna Gringauze <annagrin@microsoft.com>
Date: Thu, 12 Nov 2015 12:48:49 -0800
Subject: [PATCH 21/43] Removed basic_span class

---
 include/span.h       | 463 +++++++++++++++++++------------------------
 tests/span_tests.cpp |   4 +-
 2 files changed, 201 insertions(+), 266 deletions(-)

diff --git a/include/span.h b/include/span.h
index cbc766b..be7e74f 100644
--- a/include/span.h
+++ b/include/span.h
@@ -1045,174 +1045,6 @@ template <typename Span>
 class general_span_iterator;
 enum class byte : std::uint8_t {};
 
-template <typename ValueType, typename BoundsType>
-class basic_span
-{
-public:
-    static const size_t rank = BoundsType::rank;
-    using bounds_type = BoundsType;
-    using size_type = typename bounds_type::size_type;
-    using index_type = typename bounds_type::index_type;
-    using value_type = ValueType;
-    using const_value_type = std::add_const_t<value_type>;
-    using pointer = ValueType*;
-    using reference = ValueType&;
-    using iterator = std::conditional_t<std::is_same<typename BoundsType::mapping_type, contiguous_mapping_tag>::value, contiguous_span_iterator<basic_span>, general_span_iterator<basic_span>>;
-    using const_iterator = std::conditional_t<std::is_same<typename BoundsType::mapping_type, contiguous_mapping_tag>::value, contiguous_span_iterator<basic_span<const_value_type, BoundsType>>, general_span_iterator<basic_span<const_value_type, BoundsType>>>;
-    using reverse_iterator = std::reverse_iterator<iterator>;
-    using const_reverse_iterator = std::reverse_iterator<const_iterator>;
-    using sliced_type = std::conditional_t<rank == 1, value_type, basic_span<value_type, typename BoundsType::sliced_type>>;
-
-private:
-    pointer m_pdata;
-    bounds_type m_bounds;
-
-public:
-    constexpr bounds_type bounds() const noexcept
-    {
-        return m_bounds;
-    }
-    template <size_t Dim = 0>
-    constexpr size_type extent() const noexcept
-    {
-        static_assert(Dim < rank, "dimension should be less than rank (dimension count starts from 0)");
-        return m_bounds.template extent<Dim>();
-    }
-    constexpr size_type size() const noexcept
-    {
-        return m_bounds.size();
-    }
-    constexpr reference operator[](const index_type& idx) const
-    {
-        return m_pdata[m_bounds.linearize(idx)];
-    }
-    constexpr pointer data() const noexcept
-    {
-        return m_pdata;
-    }
-    template <bool Enabled = (rank > 1), typename Ret = std::enable_if_t<Enabled, sliced_type>>
-    constexpr Ret operator[](size_type idx) const
-    {
-        fail_fast_assert(idx < m_bounds.size(), "index is out of bounds of the array");
-        const size_type ridx = idx * m_bounds.stride();
-
-        fail_fast_assert(ridx < m_bounds.total_size(), "index is out of bounds of the underlying data");
-        return Ret {m_pdata + ridx, m_bounds.slice()};
-    }
-
-    constexpr operator bool () const noexcept
-    {
-        return m_pdata != nullptr;
-    }
-
-    constexpr iterator begin() const
-    {
-        return iterator {this, true};
-    }
-    constexpr iterator end() const
-    {
-        return iterator {this, false};
-    }
-    constexpr const_iterator cbegin() const
-    {
-        return const_iterator {reinterpret_cast<const basic_span<const value_type, bounds_type> *>(this), true};
-    }
-    constexpr const_iterator cend() const
-    {
-        return const_iterator {reinterpret_cast<const basic_span<const value_type, bounds_type> *>(this), false};
-    }
-
-    constexpr reverse_iterator rbegin() const
-    {
-        return reverse_iterator {end()};
-    }
-    constexpr reverse_iterator rend() const
-    {
-        return reverse_iterator {begin()};
-    }
-    constexpr const_reverse_iterator crbegin() const
-    {
-        return const_reverse_iterator {cend()};
-    }
-    constexpr const_reverse_iterator crend() const
-    {
-        return const_reverse_iterator {cbegin()};
-    }
-
-    template <typename OtherValueType, typename OtherBoundsType, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
-    constexpr bool operator== (const basic_span<OtherValueType, OtherBoundsType> & other) const noexcept
-    {
-        return m_bounds.size() == other.m_bounds.size() &&
-            (m_pdata == other.m_pdata || std::equal(this->begin(), this->end(), other.begin()));
-    }
-
-    template <typename OtherValueType, typename OtherBoundsType, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
-    constexpr bool operator!= (const basic_span<OtherValueType, OtherBoundsType> & other) const noexcept
-    {
-        return !(*this == other);
-    }
-
-    template <typename OtherValueType, typename OtherBoundsType, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
-    constexpr bool operator< (const basic_span<OtherValueType, OtherBoundsType> & other) const noexcept
-    {
-        return std::lexicographical_compare(this->begin(), this->end(), other.begin(), other.end());
-    }
-
-    template <typename OtherValueType, typename OtherBoundsType, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
-    constexpr bool operator<= (const basic_span<OtherValueType, OtherBoundsType> & other) const noexcept
-    {
-        return !(other < *this);
-    }
-
-    template <typename OtherValueType, typename OtherBoundsType, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
-    constexpr bool operator> (const basic_span<OtherValueType, OtherBoundsType> & other) const noexcept
-    {
-        return (other < *this);
-    }
-
-    template <typename OtherValueType, typename OtherBoundsType, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
-    constexpr bool operator>= (const basic_span<OtherValueType, OtherBoundsType> & other) const noexcept
-    {
-        return !(*this < other);
-    }
-
-public:
-    template <typename OtherValueType, typename OtherBounds,
-        typename Dummy = std::enable_if_t<std::is_convertible<OtherValueType(*)[], value_type(*)[]>::value
-            && std::is_convertible<OtherBounds, bounds_type>::value>>
-    constexpr basic_span(const basic_span<OtherValueType, OtherBounds> & other ) noexcept
-        : m_pdata(other.m_pdata), m_bounds(other.m_bounds)
-    {
-    }
-protected:
-
-    constexpr basic_span(pointer data, bounds_type bound) noexcept
-        : m_pdata(data)
-        , m_bounds(std::move(bound))
-    {
-        fail_fast_assert((m_bounds.size() > 0 && data != nullptr) || m_bounds.size() == 0);
-    }
-    template <typename T>
-    constexpr basic_span(T *data, std::enable_if_t<std::is_same<value_type, std::remove_all_extents_t<T>>::value, bounds_type> bound) noexcept
-        : m_pdata(reinterpret_cast<pointer>(data))
-        , m_bounds(std::move(bound))
-    {
-        fail_fast_assert((m_bounds.size() > 0 && data != nullptr) || m_bounds.size() == 0);
-    }
-    template <typename DestBounds>
-    constexpr basic_span<value_type, DestBounds> as_span(const DestBounds &bounds)
-    {
-        details::verifyBoundsReshape(m_bounds, bounds);
-        return {m_pdata, bounds};
-    }
-private:
-
-    friend iterator;
-    friend const_iterator;
-    template <typename ValueType2, typename BoundsType2>
-    friend class basic_span;
-};
-
 template <std::ptrdiff_t DimSize = dynamic_range>
 struct dim
 {
@@ -1328,15 +1160,14 @@ class span
     friend class span;
 
 public:
-    using BoundsType = static_bounds<FirstDimension, RestDimensions...>;
-    static const size_t rank = BoundsType::rank;
-    using bounds_type = BoundsType;
+    using bounds_type = static_bounds<FirstDimension, RestDimensions...>;
+    static const size_t rank = bounds_type::rank;
     using size_type = typename bounds_type::size_type;
     using index_type = typename bounds_type::index_type;
     using value_type = ValueType;
     using const_value_type = std::add_const_t<value_type>;
-    using pointer = ValueType*;
-    using reference = ValueType&;
+    using pointer = std::add_pointer_t<value_type>;
+    using reference = std::add_lvalue_reference_t<value_type>;
     using iterator = contiguous_span_iterator<span>;
     using const_span = span<const_value_type, FirstDimension, RestDimensions...>;
     using const_iterator = contiguous_span_iterator<const_span>;
@@ -1353,40 +1184,45 @@ private:
 
 public:
 
-    constexpr span(pointer data, bounds_type bound) noexcept
-        : m_pdata(data), m_bounds(std::move(bound))
+    constexpr span(pointer data, bounds_type bounds) noexcept
+        : m_pdata(data), m_bounds(std::move(bounds))
     {
         fail_fast_assert((m_bounds.size() > 0 && data != nullptr) || m_bounds.size() == 0);
     }
 
-    constexpr span(pointer ptr, size_type size) : span(ptr, bounds_type{ size })
+    constexpr span(pointer ptr, size_type size) noexcept
+        : span(ptr, bounds_type{ size })
     {}
 
-    constexpr span(std::nullptr_t) : span(nullptr, bounds_type{})
+    constexpr span(std::nullptr_t) noexcept
+        : span(nullptr, bounds_type{})
     {}
 
-    constexpr span(std::nullptr_t, size_type size) : span(nullptr, bounds_type{})
+    constexpr span(std::nullptr_t, size_type size) noexcept
+        : span(nullptr, bounds_type{})
     {
         fail_fast_assert(size == 0);
     }
 
     // default
     template <std::ptrdiff_t DynamicRank = bounds_type::dynamic_rank, typename = std::enable_if_t<DynamicRank != 0>>
-    constexpr span() : span(nullptr, bounds_type())
+    constexpr span() noexcept
+        : span(nullptr, bounds_type())
     {}
 
     // from n-dimensions dynamic array (e.g. new int[m][4]) (precedence will be lower than the 1-dimension pointer)
-    template <typename T, typename Helper = details::SpanArrayTraits<T, dynamic_range>
+    template <typename T, typename Helper = details::SpanArrayTraits<T, dynamic_range>,
+        typename Dummy = std::enable_if_t<std::is_same<value_type, std::remove_all_extents_t<T>>::value>
         /*typename Dummy = std::enable_if_t<std::is_convertible<Helper::value_type (*)[], value_type (*)[]>::value>*/
     >
-    constexpr span(T* const& data, size_type size) : span(data, typename Helper::bounds_type{size})
+    constexpr span(T* const& data, size_type size) : span(reinterpret_cast<pointer>(data), typename Helper::bounds_type{size})
     {}
 
     // from n-dimensions static array
     template <typename T, size_t N, typename Helper = details::SpanArrayTraits<T, N>,
         typename = std::enable_if_t<std::is_convertible<typename Helper::value_type(*)[], value_type(*)[]>::value>
     >
-    constexpr span (T (&arr)[N]) : span(arr, typename Helper::bounds_type())
+    constexpr span (T (&arr)[N]) : span(reinterpret_cast<pointer>(arr), typename Helper::bounds_type())
     {}
 
     // from n-dimensions static array with size
@@ -1436,13 +1272,13 @@ public:
         typename OtherBounds = static_bounds<OtherDimensions...>,
         typename Dummy = std::enable_if_t<std::is_convertible<OtherValueType, ValueType>::value && std::is_convertible<OtherBounds, bounds_type>::value>
     >
-    constexpr span(const span<OtherValueType, OtherDimensions...>& other)
+    constexpr span(const span<OtherValueType, OtherDimensions...>& other) noexcept
         : m_pdata(other.m_pdata), m_bounds(other.m_bounds)
     {}
 
     // reshape
     // DimCount here is a workaround for a bug in MSVC 2015
-    template <typename... Dimensions2, size_t DimCount = sizeof...(Dimensions2), typename = std::enable_if_t<(DimCount > 0)>>
+    template <typename... Dimensions2, size_t DimCount = sizeof...(Dimensions2), bool Enabled = (DimCount > 0), typename Dummy = std::enable_if_t<Enabled>>
     constexpr span<ValueType, Dimensions2::value...> as_span(Dimensions2... dims)
     {
         using BoundsType = typename span<ValueType, (Dimensions2::value)...>::bounds_type;
@@ -1550,19 +1386,19 @@ public:
     }
 
     // section
-    constexpr strided_span<ValueType, rank> section(index_type origin, index_type extents) const
+    constexpr strided_span<ValueType, rank> section(index_type origin, index_type extents) const noexcept
     {
         size_type size = this->bounds().total_size() - this->bounds().linearize(origin);
         return{ &this->operator[](origin), size, strided_bounds<rank> {extents, details::make_stride(bounds())} };
     }
     
-    constexpr reference operator[](const index_type& idx) const
+    constexpr reference operator[](const index_type& idx) const noexcept
     {
         return m_pdata[m_bounds.linearize(idx)];
     }
     
     template <bool Enabled = (rank > 1), typename Ret = std::enable_if_t<Enabled, sliced_type>>
-    constexpr Ret operator[](size_type idx) const
+    constexpr Ret operator[](size_type idx) const noexcept
     {
         fail_fast_assert(idx < m_bounds.size(), "index is out of bounds of the array");
         const size_type ridx = idx * m_bounds.stride();
@@ -1598,42 +1434,42 @@ public:
         return m_pdata != nullptr;
     }
 
-    constexpr iterator begin() const
+    constexpr iterator begin() const noexcept
     {
         return iterator{ this, true };
     }
 
-    constexpr iterator end() const
+    constexpr iterator end() const noexcept
     {
         return iterator{ this, false };
     }
 
-    constexpr const_iterator cbegin() const
+    constexpr const_iterator cbegin() const noexcept
     {
         return const_iterator{ reinterpret_cast<const const_span*>(this), true };
     }
 
-    constexpr const_iterator cend() const
+    constexpr const_iterator cend() const noexcept
     {
         return const_iterator{ reinterpret_cast<const const_span*>(this), false };
     }
 
-    constexpr reverse_iterator rbegin() const
+    constexpr reverse_iterator rbegin() const noexcept
     {
         return reverse_iterator{ end() };
     }
 
-    constexpr reverse_iterator rend() const
+    constexpr reverse_iterator rend() const noexcept
     {
         return reverse_iterator{ begin() };
     }
 
-    constexpr const_reverse_iterator crbegin() const
+    constexpr const_reverse_iterator crbegin() const noexcept
     {
         return const_reverse_iterator{ cend() };
     }
 
-    constexpr const_reverse_iterator crend() const
+    constexpr const_reverse_iterator crend() const noexcept
     {
         return const_reverse_iterator{ cbegin() };
     }
@@ -1674,22 +1510,6 @@ public:
     {
         return !(*this < other);
     }
-
-private:
-
-    template <typename T>
-    constexpr span(T *data, std::enable_if_t<std::is_same<value_type, std::remove_all_extents_t<T>>::value, bounds_type> bound) noexcept
-        : m_pdata(reinterpret_cast<pointer>(data)), m_bounds(std::move(bound))
-    {
-        fail_fast_assert((m_bounds.size() > 0 && data != nullptr) || m_bounds.size() == 0);
-    }
-
-    template <std::ptrdiff_t... OtherDimensions>
-    constexpr span<value_type, OtherDimensions...> as_span(const static_bounds<OtherDimensions...> &bounds)
-    {
-        details::verifyBoundsReshape(m_bounds, bounds);
-        return{ m_pdata, bounds };
-    }
 };
 
 template <typename T, std::ptrdiff_t... Dimensions>
@@ -1744,56 +1564,62 @@ constexpr auto as_span(Cont &&arr) -> std::enable_if_t<!details::is_span<std::de
     span<std::remove_reference_t<decltype(arr.size(), *arr.data())>, dynamic_range>> = delete;
 
 template <typename ValueType, size_t Rank>
-class strided_span : public basic_span<ValueType, strided_bounds<Rank>>
+class strided_span
 {
-    using Base = basic_span<ValueType, strided_bounds<Rank>>;
+public:
+    using bounds_type = strided_bounds<Rank>;
+    using size_type = typename bounds_type::size_type;
+    using index_type = typename bounds_type::index_type;
+    using value_type = ValueType;
+    using const_value_type = std::add_const_t<value_type>;
+    using pointer = std::add_pointer_t<value_type>;
+    using reference = std::add_lvalue_reference_t<value_type>;
+    using iterator = general_span_iterator<strided_span>;
+    using const_strided_span = strided_span<const_value_type, Rank>;
+    using const_iterator = general_span_iterator<const_strided_span>;
+    using reverse_iterator = std::reverse_iterator<iterator>;
+    using const_reverse_iterator = std::reverse_iterator<const_iterator>;
+    using sliced_type = std::conditional_t<Rank == 1, value_type, strided_span<value_type, Rank-1>>;
 
-    template<typename OtherValue, size_t OtherRank>
+private:
+    pointer m_pdata;
+    bounds_type m_bounds;
+
+    friend iterator;
+    friend const_iterator;
+    template <typename OtherValueType, size_t OtherRank>
     friend class strided_span;
 
 public:
-    using Base::rank;
-    using typename Base::bounds_type;
-    using typename Base::size_type;
-    using typename Base::pointer;
-    using typename Base::value_type;
-    using typename Base::index_type;
-    using typename Base::iterator;
-    using typename Base::const_iterator;
-    using typename Base::reference;
-    
-    // from static array of size N
-    template<size_type N>
-    strided_span(value_type(&values)[N], bounds_type bounds) : Base(values, std::move(bounds))
-    {
-        fail_fast_assert(this->bounds().total_size() <= N, "Bounds cross data boundaries");
-    }
-
     // from raw data
-    strided_span(pointer ptr, size_type size, bounds_type bounds): Base(ptr, std::move(bounds))
+    constexpr strided_span(pointer ptr, size_type size, bounds_type bounds)
+        : m_pdata(ptr), m_bounds(std::move(bounds))
     {
+        fail_fast_assert((m_bounds.size() > 0 && ptr != nullptr) || m_bounds.size() == 0);
         fail_fast_assert(this->bounds().total_size() <= size, "Bounds cross data boundaries");
     }
 
+    // from static array of size N
+    template<size_type N>
+    constexpr strided_span(value_type(&values)[N], bounds_type bounds) : strided_span(values, N, std::move(bounds))
+    {}
+
     // from array view
     template <std::ptrdiff_t... Dimensions, typename Dummy = std::enable_if<sizeof...(Dimensions) == Rank>>
-    strided_span(span<ValueType, Dimensions...> av, bounds_type bounds) : Base(av.data(), std::move(bounds))
-    {
-        fail_fast_assert(this->bounds().total_size() <= av.bounds().total_size(), "Bounds cross data boundaries");
-    }
+    constexpr strided_span(span<ValueType, Dimensions...> av, bounds_type bounds) : strided_span(av.data(), av.bounds().total_size(), std::move(bounds))
+    {}
     
     // convertible
     template <typename OtherValueType,
-        typename BaseType = basic_span<ValueType, strided_bounds<Rank>>,
-        typename OtherBaseType = basic_span<OtherValueType, strided_bounds<Rank>>,
-        typename Dummy = std::enable_if_t<std::is_convertible<OtherBaseType, BaseType>::value>
+        typename Dummy = std::enable_if_t<std::is_convertible<OtherValueType(*)[], value_type(*)[]>::value>
     >
-    constexpr strided_span(const strided_span<OtherValueType, Rank> &av) : Base(static_cast<const typename strided_span<OtherValueType, Rank>::Base &>(av)) // static_cast is required
+    constexpr strided_span(const strided_span<OtherValueType, Rank>& other)
+        : m_pdata(other.m_pdata), m_bounds(other.m_bounds)
     {}
 
     // convert from bytes
-        template <typename OtherValueType>
-        strided_span<typename std::enable_if<std::is_same<value_type, const byte>::value, OtherValueType>::type, rank> as_strided_span() const 
+    template <typename OtherValueType>
+    constexpr strided_span<typename std::enable_if<std::is_same<value_type, const byte>::value, OtherValueType>::type, Rank> as_strided_span() const
     {
         static_assert((sizeof(OtherValueType) >= sizeof(value_type)) && (sizeof(OtherValueType) % sizeof(value_type) == 0), "OtherValueType should have a size to contain a multiple of ValueTypes");
         auto d = static_cast<size_type>(sizeof(OtherValueType) / sizeof(value_type));
@@ -1802,54 +1628,163 @@ public:
         return{ (OtherValueType*)this->data(), size, bounds_type{ resize_extent(this->bounds().index_bounds(), d), resize_stride(this->bounds().strides(), d)} };
     }
 
-    strided_span section(index_type origin, index_type extents) const
+    constexpr strided_span section(index_type origin, index_type extents) const
     {
         size_type size = this->bounds().total_size() - this->bounds().linearize(origin);
-        return { &this->operator[](origin), size, bounds_type {extents, details::make_stride(Base::bounds())}};
+        return { &this->operator[](origin), size, bounds_type {extents, details::make_stride(bounds())}};
     }
 
     constexpr reference operator[](const index_type& idx) const
     {
-        return Base::operator[](idx);
+        return m_pdata[m_bounds.linearize(idx)];
     }
 
-    template <bool Enabled = (rank > 1), typename Dummy = std::enable_if_t<Enabled>>
-    constexpr strided_span<value_type, rank-1> operator[](size_type idx) const
+    template <bool Enabled = (Rank > 1), typename Ret = std::enable_if_t<Enabled, sliced_type>>
+    constexpr Ret operator[](size_type idx) const
     {
-        auto ret = Base::operator[](idx);
-        return{ ret.data(), ret.bounds().total_size(), ret.bounds() };
+        fail_fast_assert(idx < m_bounds.size(), "index is out of bounds of the array");
+        const size_type ridx = idx * m_bounds.stride();
+
+        fail_fast_assert(ridx < m_bounds.total_size(), "index is out of bounds of the underlying data");
+        return{ m_pdata + ridx, m_bounds.slice().total_size(), m_bounds.slice() };
+    }
+
+    constexpr bounds_type bounds() const noexcept
+    {
+        return m_bounds;
+    }
+
+    template <size_t Dim = 0>
+    constexpr size_type extent() const noexcept
+    {
+        static_assert(Dim < Rank, "dimension should be less than Rank (dimension count starts from 0)");
+        return m_bounds.template extent<Dim>();
+    }
+
+    constexpr size_type size() const noexcept
+    {
+        return m_bounds.size();
+    }
+
+    constexpr pointer data() const noexcept
+    {
+        return m_pdata;
+    }
+
+    constexpr operator bool() const noexcept
+    {
+        return m_pdata != nullptr;
+    }
+
+    constexpr iterator begin() const
+    {
+        return iterator{ this, true };
+    }
+
+    constexpr iterator end() const
+    {
+        return iterator{ this, false };
+    }
+
+    constexpr const_iterator cbegin() const
+    {
+        return const_iterator{ reinterpret_cast<const const_strided_span*>(this), true };
+    }
+
+    constexpr const_iterator cend() const
+    {
+        return const_iterator{ reinterpret_cast<const const_strided_span*>(this), false };
+    }
+
+    constexpr reverse_iterator rbegin() const
+    {
+        return reverse_iterator{ end() };
+    }
+
+    constexpr reverse_iterator rend() const
+    {
+        return reverse_iterator{ begin() };
+    }
+
+    constexpr const_reverse_iterator crbegin() const
+    {
+        return const_reverse_iterator{ cend() };
+    }
+
+    constexpr const_reverse_iterator crend() const
+    {
+        return const_reverse_iterator{ cbegin() };
+    }
+
+    template <typename OtherValueType, std::ptrdiff_t OtherRank, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
+    constexpr bool operator== (const strided_span<OtherValueType, OtherRank>& other) const noexcept
+    {
+        return m_bounds.size() == other.m_bounds.size() &&
+            (m_pdata == other.m_pdata || std::equal(this->begin(), this->end(), other.begin()));
+    }
+
+    template <typename OtherValueType, std::ptrdiff_t OtherRank, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
+    constexpr bool operator!= (const strided_span<OtherValueType, OtherRank>& other) const noexcept
+    {
+        return !(*this == other);
+    }
+
+    template <typename OtherValueType, std::ptrdiff_t OtherRank, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
+    constexpr bool operator< (const strided_span<OtherValueType, OtherRank>& other) const noexcept
+    {
+        return std::lexicographical_compare(this->begin(), this->end(), other.begin(), other.end());
+    }
+
+    template <typename OtherValueType, std::ptrdiff_t OtherRank, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
+    constexpr bool operator<= (const strided_span<OtherValueType, OtherRank>& other) const noexcept
+    {
+        return !(other < *this);
+    }
+
+    template <typename OtherValueType, std::ptrdiff_t OtherRank, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
+    constexpr bool operator> (const strided_span<OtherValueType, OtherRank>& other) const noexcept
+    {
+        return (other < *this);
+    }
+
+    template <typename OtherValueType, std::ptrdiff_t OtherRank, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
+    constexpr bool operator>= (const strided_span<OtherValueType, OtherRank>& other) const noexcept
+    {
+        return !(*this < other);
     }
 
 private:
     static index_type resize_extent(const index_type& extent, std::ptrdiff_t d)
     {
-        fail_fast_assert(extent[rank - 1] >= d && (extent[rank-1] % d == 0), "The last dimension of the array needs to contain a multiple of new type elements");
+        fail_fast_assert(extent[Rank - 1] >= d && (extent[Rank-1] % d == 0), "The last dimension of the array needs to contain a multiple of new type elements");
 
         index_type ret = extent;
-        ret[rank - 1] /= d;
+        ret[Rank - 1] /= d;
 
         return ret;
     }
 
-    template <bool Enabled = (rank == 1), typename Dummy = std::enable_if_t<Enabled>>
+    template <bool Enabled = (Rank == 1), typename Dummy = std::enable_if_t<Enabled>>
     static index_type resize_stride(const index_type& strides, std::ptrdiff_t , void * = 0)
     {
-        fail_fast_assert(strides[rank - 1] == 1, "Only strided arrays with regular strides can be resized");
+        fail_fast_assert(strides[Rank - 1] == 1, "Only strided arrays with regular strides can be resized");
 
         return strides;
     }
 
-    template <bool Enabled = (rank > 1), typename Dummy = std::enable_if_t<Enabled>>
+    template <bool Enabled = (Rank > 1), typename Dummy = std::enable_if_t<Enabled>>
     static index_type resize_stride(const index_type& strides, std::ptrdiff_t d)
     {
-        fail_fast_assert(strides[rank - 1] == 1, "Only strided arrays with regular strides can be resized");
-        fail_fast_assert(strides[rank - 2] >= d && (strides[rank - 2] % d == 0), "The strides must have contiguous chunks of memory that can contain a multiple of new type elements");
+        fail_fast_assert(strides[Rank - 1] == 1, "Only strided arrays with regular strides can be resized");
+        fail_fast_assert(strides[Rank - 2] >= d && (strides[Rank - 2] % d == 0), "The strides must have contiguous chunks of memory that can contain a multiple of new type elements");
 
-        for (size_t i = rank - 1; i > 0; --i)
-            fail_fast_assert((strides[i-1] >= strides[i]) && (strides[i-1] % strides[i] == 0), "Only strided arrays with regular strides can be resized");
+        for (size_t i = Rank - 1; i > 0; --i)
+        {
+            fail_fast_assert((strides[i - 1] >= strides[i]) && (strides[i - 1] % strides[i] == 0), "Only strided arrays with regular strides can be resized");
+        }
 
         index_type ret = strides / d;
-        ret[rank - 1] = 1;
+        ret[Rank - 1] = 1;
 
         return ret;
     }
@@ -1986,12 +1921,12 @@ public:
     using typename Base::difference_type;
     using typename Base::value_type;
 private:
-    template <typename ValueType, typename Bounds>
-    friend class basic_span;
+    template <typename ValueType, size_t Rank>
+    friend class strided_span;
     
-    const Span * m_container;
+    const Span* m_container;
     typename Span::bounds_type::iterator m_itr;
-    general_span_iterator(const Span *container, bool isbegin) :
+    general_span_iterator(const Span* container, bool isbegin) :
         m_container(container), m_itr(isbegin ? m_container->bounds().begin() : m_container->bounds().end())
     {}
 public:
@@ -2115,7 +2050,7 @@ general_span_iterator<Span> operator+(typename general_span_iterator<Span>::diff
 #endif // _MSC_VER
 
 #if defined(GSL_THROWS_FOR_TESTING) 
-#undef noexcept 
+#undef noexcept
 #endif // GSL_THROWS_FOR_TESTING 
 
 
diff --git a/tests/span_tests.cpp b/tests/span_tests.cpp
index ecb2c4e..8a7c552 100644
--- a/tests/span_tests.cpp
+++ b/tests/span_tests.cpp
@@ -284,7 +284,7 @@ SUITE(span_tests)
 		CHECK((av_section_2[{0, 1}] == 25));
 		CHECK((av_section_2[{1, 0}] == 34));
 	}
- 
+
 	TEST(strided_span_constructors)
 	{
 		// Check stride constructor
@@ -1406,7 +1406,7 @@ SUITE(span_tests)
 		}
 	}
 
-	TEST(custmized_span_size)
+	TEST(customized_span_size)
 	{
 		double (*arr)[3][4] = new double[100][3][4];
 		span<double, dynamic_range, 3, 4> av1(arr, 10);

From e51eb228ae54e1674da14a73b84541f791ea57f7 Mon Sep 17 00:00:00 2001
From: Lukas Haselsteiner <post@lukas-haselsteiner.at>
Date: Sun, 15 Nov 2015 23:08:35 +0100
Subject: [PATCH 22/43] fixes pragma undef warnings in MSVC2013

---
 include/gsl.h  | 2 +-
 include/span.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/gsl.h b/include/gsl.h
index e20ac69..bcaf57a 100644
--- a/include/gsl.h
+++ b/include/gsl.h
@@ -219,7 +219,7 @@ namespace std
 #pragma warning(pop)
 
 #ifndef GSL_THROWS_FOR_TESTING
-#pragma undef noexcept
+#undef noexcept
 #endif // GSL_THROWS_FOR_TESTING
 
 #endif // _MSC_VER <= 1800
diff --git a/include/span.h b/include/span.h
index be7e74f..a8cd899 100644
--- a/include/span.h
+++ b/include/span.h
@@ -2038,7 +2038,7 @@ general_span_iterator<Span> operator+(typename general_span_iterator<Span>::diff
 #pragma warning(pop)
 
 #ifndef GSL_THROWS_FOR_TESTING
-#pragma undef noexcept
+#undef noexcept
 #endif // GSL_THROWS_FOR_TESTING
 
 #undef GSL_MSVC_HAS_VARIADIC_CTOR_BUG 

From 292f81e5efc7a847a2bd69a7dccb289588193a9e Mon Sep 17 00:00:00 2001
From: Neil MacIntosh <neilmac@microsoft.com>
Date: Tue, 17 Nov 2015 15:07:51 -0800
Subject: [PATCH 23/43] Tidied up compiler-config macros.

---
 include/span.h        | 29 +++++++++++++++++++++++++----
 include/string_span.h |  2 --
 2 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/include/span.h b/include/span.h
index be7e74f..6882f40 100644
--- a/include/span.h
+++ b/include/span.h
@@ -39,16 +39,21 @@
 #pragma push_macro("constexpr")
 #define constexpr /* nothing */
 
+// MSVC has the potential of bringing in headers where max is a macro
+#ifdef max
+#pragma push_macro("max")
+#undef max
+#endif 
 
 // VS 2013 workarounds
 #if _MSC_VER <= 1800
 
-#pragma push_macro("GSL_MSVC_HAS_VARIADIC_CTOR_BUG") 
+// needed in span.h
 #define GSL_MSVC_HAS_VARIADIC_CTOR_BUG 
 
-
 // noexcept is not understood 
 #ifndef GSL_THROWS_FOR_TESTING
+#pragma push_macro("noexcept")
 #define noexcept /* nothing */ 
 #endif
 
@@ -63,7 +68,13 @@
 
 // In order to test the library, we need it to throw exceptions that we can catch
 #ifdef GSL_THROWS_FOR_TESTING
+
+#ifdef _MSC_VER
+#pragma push_macro("noexcept")
+#endif
+
 #define noexcept /* nothing */ 
+
 #endif // GSL_THROWS_FOR_TESTING 
 
 
@@ -2029,28 +2040,38 @@ general_span_iterator<Span> operator+(typename general_span_iterator<Span>::diff
 
 } // namespace gsl
 
+
 #ifdef _MSC_VER
 
 #undef constexpr
 #pragma pop_macro("constexpr")
 
+#ifdef max
+#pragma pop_macro("max")
+#endif
+
 #if _MSC_VER <= 1800
 #pragma warning(pop)
 
 #ifndef GSL_THROWS_FOR_TESTING
 #pragma undef noexcept
+#pragma pop_macro("noexcept")
 #endif // GSL_THROWS_FOR_TESTING
 
 #undef GSL_MSVC_HAS_VARIADIC_CTOR_BUG 
-#pragma pop_macro("GSL_MSVC_HAS_VARIADIC_CTOR_BUG") 
-
 
 #endif // _MSC_VER <= 1800
 
 #endif // _MSC_VER
 
 #if defined(GSL_THROWS_FOR_TESTING) 
+
 #undef noexcept
+
+#ifdef _MSC_VER
+#pragma pop_macro("noexcept")
+#endif
+
 #endif // GSL_THROWS_FOR_TESTING 
 
 
diff --git a/include/string_span.h b/include/string_span.h
index 7194c85..b30ebf0 100644
--- a/include/string_span.h
+++ b/include/string_span.h
@@ -26,7 +26,6 @@
 #ifdef _MSC_VER
 #if _MSC_VER <= 1800
 
-#pragma push_macro("GSL_MSVC_HAS_TYPE_DEDUCTION_BUG") 
 #define GSL_MSVC_HAS_TYPE_DEDUCTION_BUG 
 
 #endif // _MSC_VER <= 1800
@@ -217,7 +216,6 @@ using wzstring_builder = basic_zstring_builder<wchar_t, Max>;
 #ifdef _MSC_VER
 #if _MSC_VER <= 1800
 
-#pragma pop_macro("GSL_MSVC_HAS_TYPE_DEDUCTION_BUG") 
 #undef GSL_MSVC_HAS_TYPE_DEDUCTION_BUG 
 
 #endif // _MSC_VER <= 1800

From 106262f1ef68813e64854524634b19c37c4f1cdb Mon Sep 17 00:00:00 2001
From: Neil MacIntosh <neilmac@microsoft.com>
Date: Tue, 17 Nov 2015 19:01:46 -0800
Subject: [PATCH 24/43] Remove unnecessary workaround for max macro

---
 include/span.h | 10 ----------
 1 file changed, 10 deletions(-)

diff --git a/include/span.h b/include/span.h
index a8d0542..7fd711c 100644
--- a/include/span.h
+++ b/include/span.h
@@ -39,12 +39,6 @@
 #pragma push_macro("constexpr")
 #define constexpr /* nothing */
 
-// MSVC has the potential of bringing in headers where max is a macro
-#ifdef max
-#pragma push_macro("max")
-#undef max
-#endif 
-
 // VS 2013 workarounds
 #if _MSC_VER <= 1800
 
@@ -2046,10 +2040,6 @@ general_span_iterator<Span> operator+(typename general_span_iterator<Span>::diff
 #undef constexpr
 #pragma pop_macro("constexpr")
 
-#ifdef max
-#pragma pop_macro("max")
-#endif
-
 #if _MSC_VER <= 1800
 #pragma warning(pop)
 

From da75d0e7577aa01d3e307a6454ab500002d73b23 Mon Sep 17 00:00:00 2001
From: Matus Chochlik <chochlik@gmail.com>
Date: Wed, 18 Nov 2015 17:43:59 +0100
Subject: [PATCH 25/43] Added explicit cast to size_type in span constructor

This silences implicit sign conversion warnings when constructing span
from containers which return size_t from size().
---
 include/span.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/span.h b/include/span.h
index 7fd711c..8a406ee 100644
--- a/include/span.h
+++ b/include/span.h
@@ -1267,7 +1267,7 @@ public:
         && std::is_convertible<DataType (*)[], value_type (*)[]>::value
         && std::is_same<std::decay_t<decltype(std::declval<Cont>().size(), *std::declval<Cont>().data())>, DataType>::value>
     >
-    constexpr span (Cont& cont) : span(static_cast<pointer>(cont.data()), details::newBoundsHelper<bounds_type>(cont.size()))
+    constexpr span (Cont& cont) : span(static_cast<pointer>(cont.data()), details::newBoundsHelper<bounds_type>(static_cast<size_type>(cont.size())))
     {}
 
     constexpr span(const span &) = default;

From 73ec6886743ef1ab98e857e0db0197a2f3b2a4c8 Mon Sep 17 00:00:00 2001
From: Matus Chochlik <chochlik@gmail.com>
Date: Thu, 19 Nov 2015 10:27:08 +0100
Subject: [PATCH 26/43] Made conversion of span<> to bool explicit

---
 include/span.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/span.h b/include/span.h
index 8a406ee..dcce344 100644
--- a/include/span.h
+++ b/include/span.h
@@ -1434,7 +1434,7 @@ public:
         return m_pdata;
     }
 
-    constexpr operator bool() const noexcept
+    constexpr explicit operator bool() const noexcept
     {
         return m_pdata != nullptr;
     }
@@ -1676,7 +1676,7 @@ public:
         return m_pdata;
     }
 
-    constexpr operator bool() const noexcept
+    constexpr explicit operator bool() const noexcept
     {
         return m_pdata != nullptr;
     }

From c95eb57d3f43bf1ad19af79c463a5991a0bd7f6d Mon Sep 17 00:00:00 2001
From: Anna Gringauze <annagrin@microsoft.com>
Date: Thu, 19 Nov 2015 12:02:06 -0800
Subject: [PATCH 27/43] Fixed conversion problem when creating strided_span
 from span and bounds

---
 include/span.h       | 8 ++++++--
 tests/span_tests.cpp | 8 ++++----
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/include/span.h b/include/span.h
index dcce344..74a5e11 100644
--- a/include/span.h
+++ b/include/span.h
@@ -1610,8 +1610,12 @@ public:
     {}
 
     // from array view
-    template <std::ptrdiff_t... Dimensions, typename Dummy = std::enable_if<sizeof...(Dimensions) == Rank>>
-    constexpr strided_span(span<ValueType, Dimensions...> av, bounds_type bounds) : strided_span(av.data(), av.bounds().total_size(), std::move(bounds))
+    template <typename OtherValueType, std::ptrdiff_t... Dimensions,
+        bool Enabled1 = (sizeof...(Dimensions) == Rank),
+        bool Enabled2 = std::is_convertible<OtherValueType*, ValueType*>::value,
+        typename Dummy = std::enable_if_t<Enabled1 && Enabled2>
+    >
+    constexpr strided_span(span<OtherValueType, Dimensions...> av, bounds_type bounds) : strided_span(av.data(), av.bounds().total_size(), std::move(bounds))
     {}
     
     // convertible
diff --git a/tests/span_tests.cpp b/tests/span_tests.cpp
index 8a7c552..a78fe6e 100644
--- a/tests/span_tests.cpp
+++ b/tests/span_tests.cpp
@@ -333,7 +333,7 @@ SUITE(span_tests)
 				CHECK(sav_c[1] == 2);
 
 #if _MSC_VER > 1800
-				strided_span<volatile int, 1> sav_v{ {src}, {2, 1} };
+				strided_span<volatile int, 1> sav_v{ src, {2, 1} };
 #else
 				strided_span<volatile int, 1> sav_v{ span<volatile int>{src}, strided_bounds<1>{2, 1} };
 #endif
@@ -342,7 +342,7 @@ SUITE(span_tests)
 				CHECK(sav_v[1] == 2);
 
 #if _MSC_VER > 1800
-				strided_span<const volatile int, 1> sav_cv{ {src}, {2, 1} };
+				strided_span<const volatile int, 1> sav_cv{ src, {2, 1} };
 #else
 				strided_span<const volatile int, 1> sav_cv{ span<const volatile int>{src}, strided_bounds<1>{2, 1} };
 #endif
@@ -361,7 +361,7 @@ SUITE(span_tests)
 				CHECK(sav_c[1] == 2);
 
 #if _MSC_VER > 1800
-				strided_span<const volatile int, 1> sav_cv{ {src}, {2, 1} };
+				strided_span<const volatile int, 1> sav_cv{ src, {2, 1} };
 #else
 				strided_span<const volatile int, 1> sav_cv{ span<const volatile int>{src}, strided_bounds<1>{2, 1} };
 #endif
@@ -381,7 +381,7 @@ SUITE(span_tests)
 				CHECK(sav_v[1] == 2);
 
 #if _MSC_VER > 1800
-				strided_span<const volatile int, 1> sav_cv{ {src}, {2, 1} };
+				strided_span<const volatile int, 1> sav_cv{ src, {2, 1} };
 #else
 				strided_span<const volatile int, 1> sav_cv{ span<const volatile int>{src}, strided_bounds<1>{2, 1} };
 #endif

From e4d8d35af51aab9b072242aef0f57d8ce70625ab Mon Sep 17 00:00:00 2001
From: "Elron A. Yellin" <elron@motu.com>
Date: Fri, 20 Nov 2015 17:50:02 -0500
Subject: [PATCH 28/43] add as_span overload for basic_string which doesn't
 have nonconst .data() like other contiguous containers

---
 include/span.h       | 8 ++++++++
 tests/span_tests.cpp | 9 +++++++++
 2 files changed, 17 insertions(+)

diff --git a/include/span.h b/include/span.h
index 74a5e11..2bf9d20 100644
--- a/include/span.h
+++ b/include/span.h
@@ -1568,6 +1568,14 @@ template <typename Cont>
 constexpr auto as_span(Cont &&arr) -> std::enable_if_t<!details::is_span<std::decay_t<Cont>>::value,
     span<std::remove_reference_t<decltype(arr.size(), *arr.data())>, dynamic_range>> = delete;
 
+// from basic_string which doesn't have nonconst .data() member like other contiguous containers
+template <typename CharT, typename Traits, typename Allocator>
+constexpr auto as_span(std::basic_string<CharT, Traits, Allocator> &str) -> span<CharT, dynamic_range>
+{
+    fail_fast_assert(str.size() < PTRDIFF_MAX);
+    return {&str[0], static_cast<std::ptrdiff_t>(str.size())};
+}
+
 template <typename ValueType, size_t Rank>
 class strided_span
 {
diff --git a/tests/span_tests.cpp b/tests/span_tests.cpp
index a78fe6e..e5078af 100644
--- a/tests/span_tests.cpp
+++ b/tests/span_tests.cpp
@@ -203,6 +203,15 @@ SUITE(span_tests)
 			overloaded_func(av3.as_span(dim<>(1), dim<3>(), dim<5>()), 't');
 		}
 
+		{
+			string str;
+			span<char> strspan = as_span(str);
+			(void)strspan;
+			const string cstr;
+			span<const char> cstrspan = as_span(cstr);
+			(void)cstrspan;
+		}
+
 		{
 			int a[3][4][5];
 			auto av = as_span(a);

From d13f6daa756abd4c8e972395f667398c157728cd Mon Sep 17 00:00:00 2001
From: Neil MacIntosh <neilmac@microsoft.com>
Date: Fri, 20 Nov 2015 16:03:00 -0800
Subject: [PATCH 29/43] Refactored to use Expects/Ensures everywhere.

---
 include/fail_fast.h   |  55 ----------------
 include/gsl.h         |  40 ++++--------
 include/gsl_assert.h  |  78 +++++++++++++++++++++++
 include/span.h        | 141 +++++++++++++++++++++++-------------------
 include/string_span.h |  11 ++--
 tests/CMakeLists.txt  |   2 +-
 6 files changed, 173 insertions(+), 154 deletions(-)
 delete mode 100644 include/fail_fast.h
 create mode 100644 include/gsl_assert.h

diff --git a/include/fail_fast.h b/include/fail_fast.h
deleted file mode 100644
index b9982eb..0000000
--- a/include/fail_fast.h
+++ /dev/null
@@ -1,55 +0,0 @@
-/////////////////////////////////////////////////////////////////////////////// 
-// 
-// Copyright (c) 2015 Microsoft Corporation. All rights reserved. 
-// 
-// This code is licensed under the MIT License (MIT). 
-// 
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 
-// THE SOFTWARE. 
-// 
-///////////////////////////////////////////////////////////////////////////////
-
-#pragma once
-
-#ifndef GSL_FAIL_FAST_H
-#define GSL_FAIL_FAST_H
-
-#include <exception>
-
-#if defined(GSL_THROWS_FOR_TESTING)
-#include <stdexcept>
-#endif
-
-namespace gsl
-{
-
-//
-// Having "fail fast" result in an exception makes unit testing
-// the GSL classes that rely upon it much simpler. 
-//
-#if defined(GSL_THROWS_FOR_TESTING)
-
-struct fail_fast : public std::runtime_error 
-{
-	fail_fast() : std::runtime_error("") {}
-	explicit fail_fast(char const* const message) : std::runtime_error(message) {}
-};
-
-inline void fail_fast_assert(bool cond) { if (!cond) throw fail_fast(); }
-inline void fail_fast_assert(bool cond, const char* const message) { if (!cond) throw fail_fast(message); }
-
-#else
-
-inline void fail_fast_assert(bool cond) { if (!cond) std::terminate(); }
-inline void fail_fast_assert(bool cond, const char* const) { if (!cond) std::terminate(); }
-
-#endif // GSL_THROWS_FOR_TESTING
-
-}
-
-#endif // GSL_FAIL_FAST_H
diff --git a/include/gsl.h b/include/gsl.h
index bcaf57a..0575d57 100644
--- a/include/gsl.h
+++ b/include/gsl.h
@@ -19,6 +19,7 @@
 #ifndef GSL_GSL_H
 #define GSL_GSL_H
 
+#include "gsl_assert.h"  // Ensures/Expects
 #include "span.h"           // span, strided_span...
 #include "string_span.h"    // zstring, string_span, zstring_builder...
 #include <memory>
@@ -27,15 +28,13 @@
 
 // No MSVC does constexpr fully yet
 #pragma push_macro("constexpr")
-#define constexpr /* nothing */
+#define constexpr 
 
 // MSVC 2013 workarounds
 #if _MSC_VER <= 1800
-
 // noexcept is not understood 
-#ifndef GSL_THROWS_FOR_TESTING
-#define noexcept /* nothing */ 
-#endif
+#pragma push_macro("noexcept")
+#define noexcept  
 
 // turn off some misguided warnings
 #pragma warning(push)
@@ -45,11 +44,6 @@
 
 #endif // _MSC_VER
 
-// In order to test the library, we need it to throw exceptions that we can catch
-#ifdef GSL_THROWS_FOR_TESTING
-#define noexcept /* nothing */ 
-#endif // GSL_THROWS_FOR_TESTING 
-
 
 namespace gsl
 {
@@ -63,12 +57,6 @@ using std::shared_ptr;
 template <class T>
 using owner = T;
 
-//
-// GSL.assert: assertions
-//
-#define Expects(x)  gsl::fail_fast_assert((x))
-#define Ensures(x)  gsl::fail_fast_assert((x))
-
 //
 // GSL.util: utilities
 //
@@ -110,14 +98,14 @@ T narrow(U u) { T t = narrow_cast<T>(u); if (static_cast<U>(t) != u) throw narro
 //
 // at() - Bounds-checked way of accessing static arrays, std::array, std::vector
 //
-template <class T, size_t N>
-T& at(T(&arr)[N], size_t index) { fail_fast_assert(index < N); return arr[index]; }
+template <class T, size_t N> 
+T& at(T(&arr)[N], size_t index) { Expects(index < N); return arr[index]; }
 
 template <class T, size_t N>
-T& at(std::array<T, N>& arr, size_t index) { fail_fast_assert(index < N); return arr[index]; }
+T& at(std::array<T, N>& arr, size_t index) { Expects(index < N); return arr[index]; }
 
 template <class Cont>
-typename Cont::value_type& at(Cont& cont, size_t index) { fail_fast_assert(index < cont.size()); return cont[index]; }
+typename Cont::value_type& at(Cont& cont, size_t index) { Expects(index < cont.size()); return cont[index]; }
 
 
 //
@@ -181,7 +169,7 @@ private:
 
     // we assume that the compiler can hoist/prove away most of the checks inlined from this function
     // if not, we could make them optional via conditional compilation
-    void ensure_invariant() const { fail_fast_assert(ptr_ != nullptr); }
+    void ensure_invariant() const { Expects(ptr_ != nullptr); }
 
     // unwanted operators...pointers only point to single objects!
     // TODO ensure all arithmetic ops on this type are unavailable
@@ -216,18 +204,14 @@ namespace std
 #pragma pop_macro("constexpr")
 
 #if _MSC_VER <= 1800
-#pragma warning(pop)
 
-#ifndef GSL_THROWS_FOR_TESTING
 #undef noexcept
-#endif // GSL_THROWS_FOR_TESTING
+#pragma pop_macro("noexcept")
+ 
+#pragma warning(pop)
 
 #endif // _MSC_VER <= 1800
 
 #endif // _MSC_VER
 
-#if defined(GSL_THROWS_FOR_TESTING) 
-#undef noexcept 
-#endif // GSL_THROWS_FOR_TESTING 
-
 #endif // GSL_GSL_H
diff --git a/include/gsl_assert.h b/include/gsl_assert.h
new file mode 100644
index 0000000..4a40552
--- /dev/null
+++ b/include/gsl_assert.h
@@ -0,0 +1,78 @@
+/////////////////////////////////////////////////////////////////////////////// 
+// 
+// Copyright (c) 2015 Microsoft Corporation. All rights reserved. 
+// 
+// This code is licensed under the MIT License (MIT). 
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 
+// THE SOFTWARE. 
+// 
+///////////////////////////////////////////////////////////////////////////////
+
+#pragma once
+
+#ifndef GSL_CONTRACTS_H
+#define GSL_CONTRACTS_H
+
+#include <exception>
+
+//
+// There are three configuration options for this GSL implementation's behavior
+// when pre/post conditions on the GSL types are violated:
+//
+// 1. GSL_TERMINATE_ON_CONTRACT_VIOLATION: std::terminate will be called (default)
+// 2. GSL_THROW_ON_CONTRACT_VIOLATION: a gsl::fail_fast exception will be thrown
+// 3. GSL_UNENFORCED_ON_CONTRACT_VIOLATION: nothing happens  
+//
+#if !(defined(GSL_THROW_ON_CONTRACT_VIOLATION) ^ defined(GSL_TERMINATE_ON_CONTRACT_VIOLATION) ^ defined(GSL_UNENFORCED_ON_CONTRACT_VIOLATION))
+#define GSL_TERMINATE_ON_CONTRACT_VIOLATION 
+#endif
+
+
+#define GSL_STRINGIFY_DETAIL(x) #x
+#define GSL_STRINGIFY(x) GSL_STRINGIFY_DETAIL(x)
+
+
+//
+// GSL.assert: assertions
+//
+
+#if defined(GSL_THROW_ON_CONTRACT_VIOLATION)
+
+#include <stdexcept>
+
+namespace gsl
+{
+struct fail_fast : public std::runtime_error 
+{
+	explicit fail_fast(char const* const message) : std::runtime_error(message) {}   
+};
+}
+
+#define Expects(cond)  if (!(cond)) \
+    throw gsl::fail_fast("GSL: Precondition failure at " __FILE__ GSL_STRINGIFY(__LINE__));
+#define Ensures(cond)  if (!(cond)) \
+    throw gsl::fail_fast("GSL: Postcondition failure at " __FILE__ GSL_STRINGIFY(__LINE__));
+
+
+#elif defined(GSL_TERMINATE_ON_CONTRACT_VIOLATION)
+
+
+#define Expects(cond)           if (!(cond)) std::terminate(); 
+#define Ensures(cond)           if (!(cond)) std::terminate();
+
+
+#elif defined(GSL_UNENFORCED_ON_CONTRACT_VIOLATION)
+
+#define Expects(cond)           
+#define Ensures(cond)           
+
+#endif 
+
+
+#endif // GSL_CONTRACTS_H
diff --git a/include/span.h b/include/span.h
index a8d0542..96a7901 100644
--- a/include/span.h
+++ b/include/span.h
@@ -31,19 +31,18 @@
 #include <stdexcept>
 #include <type_traits>
 #include <utility>
-#include "fail_fast.h"
+#include <cassert>
+#include "gsl_assert.h"
 
 #ifdef _MSC_VER
 
+// turn off some warnings that are noisy about our Expects statements
+#pragma warning(push)
+#pragma warning(disable: 4127) // conditional expression is constant
+
 // No MSVC does constexpr fully yet
 #pragma push_macro("constexpr")
-#define constexpr /* nothing */
-
-// MSVC has the potential of bringing in headers where max is a macro
-#ifdef max
-#pragma push_macro("max")
-#undef max
-#endif 
+#define constexpr
 
 // VS 2013 workarounds
 #if _MSC_VER <= 1800
@@ -52,7 +51,7 @@
 #define GSL_MSVC_HAS_VARIADIC_CTOR_BUG 
 
 // noexcept is not understood 
-#ifndef GSL_THROWS_FOR_TESTING
+#ifndef GSL_THROWS_ON_CONTRACT_VIOLATION
 #pragma push_macro("noexcept")
 #define noexcept /* nothing */ 
 #endif
@@ -66,8 +65,7 @@
 
 #endif // _MSC_VER
 
-// In order to test the library, we need it to throw exceptions that we can catch
-#ifdef GSL_THROWS_FOR_TESTING
+#ifdef GSL_THROW_ON_CONTRACT_VIOLATION
 
 #ifdef _MSC_VER
 #pragma push_macro("noexcept")
@@ -75,7 +73,7 @@
 
 #define noexcept /* nothing */ 
 
-#endif // GSL_THROWS_FOR_TESTING 
+#endif // GSL_THROW_ON_CONTRACT_VIOLATION 
 
 
 namespace gsl {
@@ -143,14 +141,14 @@ public:
     // Preconditions: component_idx < rank
     constexpr reference operator[](size_t component_idx)
     {
-        fail_fast_assert(component_idx < Rank, "Component index must be less than rank");
+        Expects(component_idx < Rank); // Component index must be less than rank
         return elems[component_idx];
     }
 
     // Preconditions: component_idx < rank
     constexpr const_reference operator[](size_t component_idx) const noexcept
     {
-        fail_fast_assert(component_idx < Rank, "Component index must be less than rank");
+        Expects(component_idx < Rank); // Component index must be less than rank
         return elems[component_idx];
     }
 
@@ -350,7 +348,7 @@ namespace details
         
             BoundsRanges(const std::ptrdiff_t* const arr) : Base(arr + 1), m_bound(*arr * this->Base::totalSize())
         {
-            fail_fast_assert(0 <= *arr);
+            Expects(0 <= *arr);
         }
 
         BoundsRanges() : m_bound(0) {}
@@ -371,7 +369,7 @@ namespace details
         size_type linearize(const T& arr) const
         { 
             const size_type index = this->Base::totalSize() * arr[Dim];
-            fail_fast_assert(index < m_bound);
+            Expects(index < m_bound);
             return index + this->Base::template linearize<T, Dim + 1>(arr);
         }
         
@@ -425,8 +423,9 @@ namespace details
 
         template <std::ptrdiff_t OtherRange, std::ptrdiff_t... RestOtherRanges>
         BoundsRanges(const BoundsRanges<OtherRange, RestOtherRanges...>&other, bool firstLevel = true) : Base(static_cast<const BoundsRanges<RestOtherRanges...>&>(other), false)
-        {
-            fail_fast_assert((firstLevel && totalSize() <= other.totalSize()) || totalSize() == other.totalSize());
+        {            
+            Expects((firstLevel && totalSize() <= other.totalSize()) || totalSize() == other.totalSize());
+            (void)firstLevel;
         }
 
         template <typename T, size_t Dim = 0>
@@ -439,7 +438,7 @@ namespace details
         template <typename T, size_t Dim = 0>
         size_type linearize(const T& arr) const
         {  
-            fail_fast_assert(arr[Dim] < CurrentRange, "Index is out of range");
+            Expects(arr[Dim] < CurrentRange); // Index is out of range
             return this->Base::totalSize() * arr[Dim] + this->Base::template linearize<T, Dim + 1>(arr);
         }
 
@@ -590,8 +589,10 @@ public:
                                                        
     constexpr static_bounds(std::initializer_list<size_type> il) : m_ranges((const std::ptrdiff_t*)il.begin())
     {
-        fail_fast_assert((MyRanges::DynamicNum == 0 && il.size() == 1 && *il.begin() == static_size) || MyRanges::DynamicNum == il.size(), "Size of the initializer list must match the rank of the array");
-        fail_fast_assert(m_ranges.totalSize() <= PTRDIFF_MAX, "Size of the range is larger than the max element of the size type");
+        // Size of the initializer list must match the rank of the array
+        Expects((MyRanges::DynamicNum == 0 && il.size() == 1 && *il.begin() == static_size) || MyRanges::DynamicNum == il.size()); 
+        // Size of the range must be less than the max element of the size type
+        Expects(m_ranges.totalSize() <= PTRDIFF_MAX); 
     }
     
     constexpr static_bounds() = default;
@@ -748,7 +749,7 @@ public:
         size_type ret = 0;
         for (size_t i = 0; i < rank; i++)
         {
-            fail_fast_assert(idx[i] < m_extents[i], "index is out of bounds of the array");
+            Expects(idx[i] < m_extents[i]); // index is out of bounds of the array
             ret += idx[i] * m_strides[i];
         }
         return ret;
@@ -874,7 +875,7 @@ public:
         }
         // If we're here the preconditions were violated
         // "pre: there exists s such that r == ++s"
-        fail_fast_assert(false);
+        Expects(false); 
         return *this;
     }
 
@@ -905,7 +906,8 @@ public:
             curr[i] = linear_idx / stride[i];
             linear_idx = linear_idx % stride[i];
         }
-        fail_fast_assert(!less(curr, index_type{}) && !less(boundary, curr), "index is out of bounds of the array");
+        //index is out of bounds of the array
+        Expects(!less(curr, index_type{}) && !less(boundary, curr));
         return *this;
     }
 
@@ -1044,7 +1046,7 @@ namespace details
         static_assert(is_bounds<BoundsSrc>::value && is_bounds<BoundsDest>::value, "The src type and dest type must be bounds");
         static_assert(std::is_same<typename BoundsSrc::mapping_type, contiguous_mapping_tag>::value, "The source type must be a contiguous bounds");
         static_assert(BoundsDest::static_size == dynamic_range || BoundsSrc::static_size == dynamic_range || BoundsDest::static_size == BoundsSrc::static_size, "The source bounds must have same size as dest bounds");
-        fail_fast_assert(src.size() == dest.size());
+        Expects(src.size() == dest.size());
     }
 
 
@@ -1105,13 +1107,13 @@ namespace details
     template <typename BoundsType>
     BoundsType newBoundsHelperImpl(std::ptrdiff_t totalSize, std::true_type) // dynamic size
     {
-        fail_fast_assert(totalSize <= PTRDIFF_MAX);
+        Expects(totalSize <= PTRDIFF_MAX);
         return BoundsType{totalSize};
     }
     template <typename BoundsType>
     BoundsType newBoundsHelperImpl(std::ptrdiff_t totalSize, std::false_type) // static size
     {
-        fail_fast_assert(BoundsType::static_size == totalSize);
+        Expects(BoundsType::static_size == totalSize);
         return {};
     }
     template <typename BoundsType>
@@ -1198,7 +1200,7 @@ public:
     constexpr span(pointer data, bounds_type bounds) noexcept
         : m_pdata(data), m_bounds(std::move(bounds))
     {
-        fail_fast_assert((m_bounds.size() > 0 && data != nullptr) || m_bounds.size() == 0);
+        Expects((m_bounds.size() > 0 && data != nullptr) || m_bounds.size() == 0);
     }
 
     constexpr span(pointer ptr, size_type size) noexcept
@@ -1212,7 +1214,7 @@ public:
     constexpr span(std::nullptr_t, size_type size) noexcept
         : span(nullptr, bounds_type{})
     {
-        fail_fast_assert(size == 0);
+        Expects(size == 0);
     }
 
     // default
@@ -1242,7 +1244,7 @@ public:
     >
     constexpr span(T(&arr)[N], size_type size) : span(arr, typename Helper::bounds_type{size})
     {
-        fail_fast_assert(size <= N);
+        Expects(size <= N);
     }
 
     // from std array
@@ -1319,7 +1321,7 @@ public:
     {
         static_assert(std::is_standard_layout<U>::value && (bounds_type::static_size == dynamic_range || bounds_type::static_size % static_cast<size_type>(sizeof(U)) == 0),
             "Target type must be standard layout and its size must match the byte array size");
-        fail_fast_assert((this->bytes() % sizeof(U)) == 0 && (this->bytes() / sizeof(U)) < PTRDIFF_MAX);
+        Expects((this->bytes() % sizeof(U)) == 0 && (this->bytes() / sizeof(U)) < PTRDIFF_MAX);
         return { reinterpret_cast<const U*>(this->data()), this->bytes() / static_cast<size_type>(sizeof(U)) };
     }
 
@@ -1328,7 +1330,7 @@ public:
     {
         static_assert(std::is_standard_layout<U>::value && (bounds_type::static_size == dynamic_range || bounds_type::static_size % static_cast<size_t>(sizeof(U)) == 0),
             "Target type must be standard layout and its size must match the byte array size");
-        fail_fast_assert((this->bytes() % sizeof(U)) == 0);
+        Expects((this->bytes() % sizeof(U)) == 0);
         return { reinterpret_cast<U*>(this->data()), this->bytes() / static_cast<size_type>(sizeof(U)) };
     }
 
@@ -1337,13 +1339,13 @@ public:
     constexpr span<ValueType, Count> first() const noexcept
     {
         static_assert(bounds_type::static_size == dynamic_range || Count <= bounds_type::static_size, "Index is out of bound");
-        fail_fast_assert(bounds_type::static_size != dynamic_range || Count <= this->size()); // ensures we only check condition when needed
+        Expects(bounds_type::static_size != dynamic_range || Count <= this->size()); 
         return { this->data(), Count };
     }
 
     constexpr span<ValueType, dynamic_range> first(size_type count) const noexcept
     {
-        fail_fast_assert(count <= this->size());
+        Expects(count <= this->size());
         return { this->data(), count };
     }
 
@@ -1351,13 +1353,13 @@ public:
     constexpr span<ValueType, Count> last() const noexcept
     {
         static_assert(bounds_type::static_size == dynamic_range || Count <= bounds_type::static_size, "Index is out of bound");
-        fail_fast_assert(bounds_type::static_size != dynamic_range || Count <= this->size());
+        Expects(bounds_type::static_size != dynamic_range || Count <= this->size());
         return { this->data() + this->size() - Count, Count };
     }
 
     constexpr span<ValueType, dynamic_range> last(size_type count) const noexcept
     {
-        fail_fast_assert(count <= this->size());
+        Expects(count <= this->size());
         return { this->data() + this->size() - count, count };
     }
 
@@ -1365,13 +1367,13 @@ public:
     constexpr span<ValueType, Count> sub() const noexcept
     {
         static_assert(bounds_type::static_size == dynamic_range || ((Offset == 0 || Offset <= bounds_type::static_size) && Offset + Count <= bounds_type::static_size), "Index is out of bound");
-        fail_fast_assert(bounds_type::static_size != dynamic_range || ((Offset == 0 || Offset <= this->size()) && Offset + Count <= this->size()));
+        Expects(bounds_type::static_size != dynamic_range || ((Offset == 0 || Offset <= this->size()) && Offset + Count <= this->size()));
         return { this->data() + Offset, Count };
     }
 
     constexpr span<ValueType, dynamic_range> sub(size_type offset, size_type count = dynamic_range) const noexcept
     {
-        fail_fast_assert((offset == 0 || offset <= this->size()) && (count == dynamic_range || (offset + count) <= this->size()));
+        Expects((offset == 0 || offset <= this->size()) && (count == dynamic_range || (offset + count) <= this->size()));
         return { this->data() + offset, count == dynamic_range ? this->length() - offset : count };
     }
 
@@ -1411,10 +1413,11 @@ public:
     template <bool Enabled = (rank > 1), typename Ret = std::enable_if_t<Enabled, sliced_type>>
     constexpr Ret operator[](size_type idx) const noexcept
     {
-        fail_fast_assert(idx < m_bounds.size(), "index is out of bounds of the array");
+        Expects(idx < m_bounds.size()); // index is out of bounds of the array
         const size_type ridx = idx * m_bounds.stride();
 
-        fail_fast_assert(ridx < m_bounds.total_size(), "index is out of bounds of the underlying data");
+        // index is out of bounds of the underlying data
+        Expects(ridx < m_bounds.total_size());
         return Ret{ m_pdata + ridx, m_bounds.slice() };
     }
 
@@ -1566,7 +1569,7 @@ template <typename Cont>
 constexpr auto as_span(Cont &arr) -> std::enable_if_t<!details::is_span<std::decay_t<Cont>>::value,
     span<std::remove_reference_t<decltype(arr.size(), *arr.data())>, dynamic_range>>
 {
-    fail_fast_assert(arr.size() < PTRDIFF_MAX);
+    Expects(arr.size() < PTRDIFF_MAX);
     return {arr.data(), static_cast<std::ptrdiff_t>(arr.size())};
 }
 
@@ -1606,8 +1609,10 @@ public:
     constexpr strided_span(pointer ptr, size_type size, bounds_type bounds)
         : m_pdata(ptr), m_bounds(std::move(bounds))
     {
-        fail_fast_assert((m_bounds.size() > 0 && ptr != nullptr) || m_bounds.size() == 0);
-        fail_fast_assert(this->bounds().total_size() <= size, "Bounds cross data boundaries");
+        Expects((m_bounds.size() > 0 && ptr != nullptr) || m_bounds.size() == 0);
+        // Bounds cross data boundaries
+        Expects(this->bounds().total_size() <= size);
+        (void)size;
     }
 
     // from static array of size N
@@ -1653,10 +1658,11 @@ public:
     template <bool Enabled = (Rank > 1), typename Ret = std::enable_if_t<Enabled, sliced_type>>
     constexpr Ret operator[](size_type idx) const
     {
-        fail_fast_assert(idx < m_bounds.size(), "index is out of bounds of the array");
+        Expects(idx < m_bounds.size()); // index is out of bounds of the array
         const size_type ridx = idx * m_bounds.stride();
 
-        fail_fast_assert(ridx < m_bounds.total_size(), "index is out of bounds of the underlying data");
+        // index is out of bounds of the underlying data
+        Expects(ridx < m_bounds.total_size());
         return{ m_pdata + ridx, m_bounds.slice().total_size(), m_bounds.slice() };
     }
 
@@ -1767,7 +1773,8 @@ public:
 private:
     static index_type resize_extent(const index_type& extent, std::ptrdiff_t d)
     {
-        fail_fast_assert(extent[Rank - 1] >= d && (extent[Rank-1] % d == 0), "The last dimension of the array needs to contain a multiple of new type elements");
+        // The last dimension of the array needs to contain a multiple of new type elements
+        Expects(extent[Rank - 1] >= d && (extent[Rank - 1] % d == 0));
 
         index_type ret = extent;
         ret[Rank - 1] /= d;
@@ -1778,7 +1785,8 @@ private:
     template <bool Enabled = (Rank == 1), typename Dummy = std::enable_if_t<Enabled>>
     static index_type resize_stride(const index_type& strides, std::ptrdiff_t , void * = 0)
     {
-        fail_fast_assert(strides[Rank - 1] == 1, "Only strided arrays with regular strides can be resized");
+        // Only strided arrays with regular strides can be resized
+        Expects(strides[Rank - 1] == 1);
 
         return strides;
     }
@@ -1786,12 +1794,16 @@ private:
     template <bool Enabled = (Rank > 1), typename Dummy = std::enable_if_t<Enabled>>
     static index_type resize_stride(const index_type& strides, std::ptrdiff_t d)
     {
-        fail_fast_assert(strides[Rank - 1] == 1, "Only strided arrays with regular strides can be resized");
-        fail_fast_assert(strides[Rank - 2] >= d && (strides[Rank - 2] % d == 0), "The strides must have contiguous chunks of memory that can contain a multiple of new type elements");
+        // Only strided arrays with regular strides can be resized
+        Expects(strides[Rank - 1] == 1);
+        // The strides must have contiguous chunks of
+        // memory that can contain a multiple of new type elements
+        Expects(strides[Rank - 2] >= d && (strides[Rank - 2] % d == 0));
 
         for (size_t i = Rank - 1; i > 0; --i)
         {
-            fail_fast_assert((strides[i - 1] >= strides[i]) && (strides[i - 1] % strides[i] == 0), "Only strided arrays with regular strides can be resized");
+            // Only strided arrays with regular strides can be resized
+            Expects((strides[i - 1] >= strides[i]) && (strides[i - 1] % strides[i] == 0));
         }
 
         index_type ret = strides / d;
@@ -1818,7 +1830,9 @@ private:
     const Span* m_validator;
     void validateThis() const
     {
-        fail_fast_assert(m_pdata >= m_validator->m_pdata && m_pdata < m_validator->m_pdata + m_validator->size(), "iterator is out of range of the array");
+        // iterator is out of range of the array
+        Expects(m_pdata >= m_validator->m_pdata &&
+            m_pdata < m_validator->m_pdata + m_validator->size());
     }
     contiguous_span_iterator (const Span* container, bool isbegin) :
         m_pdata(isbegin ? container->m_pdata : container->m_pdata + container->size()), m_validator(container) {}
@@ -1876,7 +1890,7 @@ public:
     }
     difference_type operator-(const contiguous_span_iterator& rhs) const noexcept
     {
-        fail_fast_assert(m_validator == rhs.m_validator);
+        Expects(m_validator == rhs.m_validator);
         return m_pdata - rhs.m_pdata;
     }
     reference operator[](difference_type n) const noexcept
@@ -1885,7 +1899,7 @@ public:
     }
     bool operator==(const contiguous_span_iterator& rhs) const noexcept
     {
-        fail_fast_assert(m_validator == rhs.m_validator);
+        Expects(m_validator == rhs.m_validator);
         return m_pdata == rhs.m_pdata;
     }
     bool operator!=(const contiguous_span_iterator& rhs) const noexcept
@@ -1894,7 +1908,7 @@ public:
     }
     bool operator<(const contiguous_span_iterator& rhs) const noexcept
     {
-        fail_fast_assert(m_validator == rhs.m_validator);
+        Expects(m_validator == rhs.m_validator);
         return m_pdata < rhs.m_pdata;
     }
     bool operator<=(const contiguous_span_iterator& rhs) const noexcept
@@ -1992,7 +2006,7 @@ public:
     }
     difference_type operator-(const general_span_iterator& rhs) const noexcept
     {
-        fail_fast_assert(m_container == rhs.m_container);
+        Expects(m_container == rhs.m_container);
         return m_itr - rhs.m_itr;
     }
     value_type operator[](difference_type n) const noexcept
@@ -2001,7 +2015,7 @@ public:
     }
     bool operator==(const general_span_iterator& rhs) const noexcept
     {
-        fail_fast_assert(m_container == rhs.m_container);
+        Expects(m_container == rhs.m_container);
         return m_itr == rhs.m_itr;
     }
     bool operator !=(const general_span_iterator& rhs) const noexcept
@@ -2010,7 +2024,7 @@ public:
     }
     bool operator<(const general_span_iterator& rhs) const noexcept
     {
-        fail_fast_assert(m_container == rhs.m_container);
+        Expects(m_container == rhs.m_container);
         return m_itr < rhs.m_itr;
     }
     bool operator<=(const general_span_iterator& rhs) const noexcept
@@ -2046,17 +2060,13 @@ general_span_iterator<Span> operator+(typename general_span_iterator<Span>::diff
 #undef constexpr
 #pragma pop_macro("constexpr")
 
-#ifdef max
-#pragma pop_macro("max")
-#endif
-
 #if _MSC_VER <= 1800
 #pragma warning(pop)
 
-#ifndef GSL_THROWS_FOR_TESTING
+#ifndef GSL_THROW_ON_CONTRACT_VIOLATION
 #undef noexcept
 #pragma pop_macro("noexcept")
-#endif // GSL_THROWS_FOR_TESTING
+#endif // GSL_THROW_ON_CONTRACT_VIOLATION
 
 #undef GSL_MSVC_HAS_VARIADIC_CTOR_BUG 
 
@@ -2064,15 +2074,16 @@ general_span_iterator<Span> operator+(typename general_span_iterator<Span>::diff
 
 #endif // _MSC_VER
 
-#if defined(GSL_THROWS_FOR_TESTING) 
+#if defined(GSL_THROW_ON_CONTRACT_VIOLATION) 
 
 #undef noexcept
 
 #ifdef _MSC_VER
+#pragma warning(pop)
 #pragma pop_macro("noexcept")
 #endif
 
-#endif // GSL_THROWS_FOR_TESTING 
+#endif // GSL_THROW_ON_CONTRACT_VIOLATION 
 
 
 #endif // GSL_SPAN_H
diff --git a/include/string_span.h b/include/string_span.h
index b30ebf0..250c528 100644
--- a/include/string_span.h
+++ b/include/string_span.h
@@ -19,6 +19,7 @@
 #ifndef GSL_STRING_SPAN_H
 #define GSL_STRING_SPAN_H
 
+#include "gsl_assert.h"
 #include "span.h"
 #include <cstring>
 
@@ -89,7 +90,7 @@ span<T, dynamic_range> ensure_sentinel(const T* seq, std::ptrdiff_t max = PTRDIF
 {
     auto cur = seq;
     while ((cur - seq) < max && *cur != Sentinel) ++cur;
-    fail_fast_assert(*cur == Sentinel);
+    Ensures(*cur == Sentinel);
     return{ seq, cur - seq };
 }
 
@@ -109,26 +110,26 @@ inline basic_string_span<T, dynamic_range> ensure_z(T* const & sz, std::ptrdiff_
 inline basic_string_span<char, dynamic_range> ensure_z(char* const& sz, std::ptrdiff_t max)
 {
     auto len = strnlen(sz, max);
-    fail_fast_assert(sz[len] == 0);
+    Ensures(sz[len] == 0);
     return{ sz, static_cast<std::ptrdiff_t>(len) };
 }
 
 inline basic_string_span<const char, dynamic_range> ensure_z(const char* const& sz, std::ptrdiff_t max)
 {
     auto len = strnlen(sz, max);
-    fail_fast_assert(sz[len] == 0); return{ sz, static_cast<std::ptrdiff_t>(len) };
+    Ensures(sz[len] == 0); return{ sz, static_cast<std::ptrdiff_t>(len) };
 }
 
 inline basic_string_span<wchar_t, dynamic_range> ensure_z(wchar_t* const& sz, std::ptrdiff_t max)
 {
     auto len = wcsnlen(sz, max);
-    fail_fast_assert(sz[len] == 0); return{ sz, static_cast<std::ptrdiff_t>(len) };
+    Ensures(sz[len] == 0); return{ sz, static_cast<std::ptrdiff_t>(len) };
 }
 
 inline basic_string_span<const wchar_t, dynamic_range> ensure_z(const wchar_t* const& sz, std::ptrdiff_t max)
 {
     auto len = wcsnlen(sz, max);
-    fail_fast_assert(sz[len] == 0); return{ sz, static_cast<std::ptrdiff_t>(len) };
+    Ensures(sz[len] == 0); return{ sz, static_cast<std::ptrdiff_t>(len) };
 }
 
 template<class T, size_t N>
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 5529cda..fe7a831 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -9,7 +9,7 @@ include_directories(
     ./unittest-cpp
 )
 
-add_definitions(-DGSL_THROWS_FOR_TESTING)
+add_definitions(-DGSL_THROW_ON_CONTRACT_VIOLATION)
 
 if(MSVC14 OR MSVC12) # has the support we need
     # remove unnecessary warnings about unchecked iterators

From 38eaf9fc95149ccdff17c6c0a9f0fbed15fc41f8 Mon Sep 17 00:00:00 2001
From: Neil MacIntosh <neilmac@microsoft.com>
Date: Mon, 23 Nov 2015 15:07:41 -0800
Subject: [PATCH 30/43] Refactored headers so span can use narrow_cast etc.

---
 include/gsl.h        |  51 +----------------
 include/gsl_util.h   | 132 +++++++++++++++++++++++++++++++++++++++++++
 tests/CMakeLists.txt |   2 +-
 3 files changed, 134 insertions(+), 51 deletions(-)
 create mode 100644 include/gsl_util.h

diff --git a/include/gsl.h b/include/gsl.h
index 0575d57..ad064ba 100644
--- a/include/gsl.h
+++ b/include/gsl.h
@@ -20,6 +20,7 @@
 #define GSL_GSL_H
 
 #include "gsl_assert.h"  // Ensures/Expects
+#include "gsl_util.h"    // finally()/narrow()/narrow_cast()...
 #include "span.h"           // span, strided_span...
 #include "string_span.h"    // zstring, string_span, zstring_builder...
 #include <memory>
@@ -57,56 +58,6 @@ using std::shared_ptr;
 template <class T>
 using owner = T;
 
-//
-// GSL.util: utilities
-//
-
-// final_act allows you to ensure something gets run at the end of a scope
-template <class F>
-class final_act
-{
-public:
-    explicit final_act(F f) noexcept : f_(std::move(f)), invoke_(true) {}
-
-    final_act(final_act&& other) noexcept : f_(std::move(other.f_)), invoke_(other.invoke_) { other.invoke_ = false; }
-    final_act(const final_act&) = delete;
-    final_act& operator=(const final_act&) = delete;
-
-    ~final_act() noexcept { if (invoke_) f_(); }
-
-private:
-    F f_;
-    bool invoke_;
-};
-
-// finally() - convenience function to generate a final_act
-template <class F>
-final_act<F> finally(const F &f) noexcept { return final_act<F>(f); }
-
-template <class F>
-final_act<F> finally(F &&f) noexcept { return final_act<F>(std::forward<F>(f)); }
-
-// narrow_cast(): a searchable way to do narrowing casts of values
-template<class T, class U>
-T narrow_cast(U u) noexcept { return static_cast<T>(u); }
-
-struct narrowing_error : public std::exception {};
-// narrow() : a checked version of narrow_cast() that throws if the cast changed the value
-template<class T, class U>
-T narrow(U u) { T t = narrow_cast<T>(u); if (static_cast<U>(t) != u) throw narrowing_error(); return t; }
-
-//
-// at() - Bounds-checked way of accessing static arrays, std::array, std::vector
-//
-template <class T, size_t N> 
-T& at(T(&arr)[N], size_t index) { Expects(index < N); return arr[index]; }
-
-template <class T, size_t N>
-T& at(std::array<T, N>& arr, size_t index) { Expects(index < N); return arr[index]; }
-
-template <class Cont>
-typename Cont::value_type& at(Cont& cont, size_t index) { Expects(index < cont.size()); return cont[index]; }
-
 
 //
 // not_null
diff --git a/include/gsl_util.h b/include/gsl_util.h
new file mode 100644
index 0000000..b6f56ce
--- /dev/null
+++ b/include/gsl_util.h
@@ -0,0 +1,132 @@
+/////////////////////////////////////////////////////////////////////////////// 
+// 
+// Copyright (c) 2015 Microsoft Corporation. All rights reserved. 
+// 
+// This code is licensed under the MIT License (MIT). 
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 
+// THE SOFTWARE. 
+// 
+///////////////////////////////////////////////////////////////////////////////
+
+#pragma once
+
+#ifndef GSL_UTIL_H
+#define GSL_UTIL_H
+
+#include "gsl_assert.h"  // Ensures/Expects
+#include <array>
+#include <utility>
+#include <exception>
+
+#ifdef _MSC_VER
+
+// No MSVC does constexpr fully yet
+#pragma push_macro("constexpr")
+#define constexpr 
+
+// MSVC 2013 workarounds
+#if _MSC_VER <= 1800
+// noexcept is not understood 
+#pragma push_macro("noexcept")
+#define noexcept  
+
+// turn off some misguided warnings
+#pragma warning(push)
+#pragma warning(disable: 4351) // warns about newly introduced aggregate initializer behavior
+
+#endif // _MSC_VER <= 1800
+
+#endif // _MSC_VER
+
+
+namespace gsl
+{
+//
+// GSL.util: utilities
+//
+
+// final_act allows you to ensure something gets run at the end of a scope
+template <class F>
+class final_act
+{
+public:
+    explicit final_act(F f) noexcept
+    : f_(std::move(f)), invoke_(true)
+    {}
+
+    final_act(final_act&& other) noexcept
+    : f_(std::move(other.f_)), invoke_(other.invoke_)
+    { other.invoke_ = false; }
+    
+    final_act(const final_act&) = delete;
+    final_act& operator=(const final_act&) = delete;
+
+    ~final_act() noexcept { if (invoke_) f_(); }
+
+private:
+    F f_;
+    bool invoke_;
+};
+
+// finally() - convenience function to generate a final_act
+template <class F>
+final_act<F> finally(const F &f)
+noexcept { return final_act<F>(f); }
+
+template <class F>
+final_act<F> finally(F &&f) noexcept
+{ return final_act<F>(std::forward<F>(f)); }
+
+// narrow_cast(): a searchable way to do narrowing casts of values
+template<class T, class U>
+constexpr T narrow_cast(U u) noexcept
+{ return static_cast<T>(u); }
+
+struct narrowing_error : public std::exception {};
+
+// narrow() : a checked version of narrow_cast() that throws if the cast changed the value
+template<class T, class U>
+T narrow(U u)
+{ T t = narrow_cast<T>(u); if (static_cast<U>(t) != u) throw narrowing_error(); return t; }
+
+//
+// at() - Bounds-checked way of accessing static arrays, std::array, std::vector
+//
+template <class T, size_t N> 
+constexpr T& at(T(&arr)[N], size_t index)
+{ Expects(index < N); return arr[index]; }
+
+template <class T, size_t N>
+constexpr T& at(std::array<T, N>& arr, size_t index)
+{ Expects(index < N); return arr[index]; }
+
+template <class Cont>
+constexpr typename Cont::value_type& at(Cont& cont, size_t index)
+{ Expects(index < cont.size()); return cont[index]; }
+
+} // namespace gsl
+
+
+#ifdef _MSC_VER
+
+#undef constexpr
+#pragma pop_macro("constexpr")
+
+#if _MSC_VER <= 1800
+
+#undef noexcept
+#pragma pop_macro("noexcept")
+ 
+#pragma warning(pop)
+
+#endif // _MSC_VER <= 1800
+
+#endif // _MSC_VER
+
+#endif // GSL_UTIL_H
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index fe7a831..a524d01 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -33,7 +33,7 @@ if (NOT EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/unittest-cpp)
 endif()
 
 function(add_gsl_test name)
-    add_executable(${name} ${name}.cpp)
+    add_executable(${name} ${name}.cpp ../include/gsl.h ../include/gsl_assert.h ../include/gsl_util.h ../include/span.h ../include/string_span.h)
     target_link_libraries(${name} UnitTest++)
     install(TARGETS ${name}
         RUNTIME DESTINATION bin

From 0cf947db7760bf5756e4cb0d47c72a257ed527c5 Mon Sep 17 00:00:00 2001
From: Neil MacIntosh <neilmac@microsoft.com>
Date: Tue, 24 Nov 2015 12:49:03 -0800
Subject: [PATCH 31/43] Reworked span to match GSL design.

---
 include/gsl_assert.h         |    4 +-
 include/gsl_util.h           |    8 +-
 include/span.h               | 1813 ++++++++++---------
 tests/CMakeLists.txt         |    1 +
 tests/span_tests.cpp         | 3306 ++++++++++++++++------------------
 tests/strided_span_tests.cpp |  748 ++++++++
 tests/string_span_tests.cpp  |    5 -
 7 files changed, 3302 insertions(+), 2583 deletions(-)
 create mode 100644 tests/strided_span_tests.cpp

diff --git a/include/gsl_assert.h b/include/gsl_assert.h
index 4a40552..81cfd13 100644
--- a/include/gsl_assert.h
+++ b/include/gsl_assert.h
@@ -55,9 +55,9 @@ struct fail_fast : public std::runtime_error
 }
 
 #define Expects(cond)  if (!(cond)) \
-    throw gsl::fail_fast("GSL: Precondition failure at " __FILE__ GSL_STRINGIFY(__LINE__));
+    throw gsl::fail_fast("GSL: Precondition failure at " __FILE__ ": " GSL_STRINGIFY(__LINE__));
 #define Ensures(cond)  if (!(cond)) \
-    throw gsl::fail_fast("GSL: Postcondition failure at " __FILE__ GSL_STRINGIFY(__LINE__));
+    throw gsl::fail_fast("GSL: Postcondition failure at " __FILE__ ": " GSL_STRINGIFY(__LINE__));
 
 
 #elif defined(GSL_TERMINATE_ON_CONTRACT_VIOLATION)
diff --git a/include/gsl_util.h b/include/gsl_util.h
index b6f56ce..e38868c 100644
--- a/include/gsl_util.h
+++ b/include/gsl_util.h
@@ -76,23 +76,23 @@ private:
 
 // finally() - convenience function to generate a final_act
 template <class F>
-final_act<F> finally(const F &f)
+inline final_act<F> finally(const F &f)
 noexcept { return final_act<F>(f); }
 
 template <class F>
-final_act<F> finally(F &&f) noexcept
+inline final_act<F> finally(F &&f) noexcept
 { return final_act<F>(std::forward<F>(f)); }
 
 // narrow_cast(): a searchable way to do narrowing casts of values
 template<class T, class U>
-constexpr T narrow_cast(U u) noexcept
+inline constexpr T narrow_cast(U u) noexcept
 { return static_cast<T>(u); }
 
 struct narrowing_error : public std::exception {};
 
 // narrow() : a checked version of narrow_cast() that throws if the cast changed the value
 template<class T, class U>
-T narrow(U u)
+inline T narrow(U u)
 { T t = narrow_cast<T>(u); if (static_cast<U>(t) != u) throw narrowing_error(); return t; }
 
 //
diff --git a/include/span.h b/include/span.h
index 0c67d22..4f0de0b 100644
--- a/include/span.h
+++ b/include/span.h
@@ -1,17 +1,17 @@
-/////////////////////////////////////////////////////////////////////////////// 
-// 
-// Copyright (c) 2015 Microsoft Corporation. All rights reserved. 
-// 
-// This code is licensed under the MIT License (MIT). 
-// 
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 
-// THE SOFTWARE. 
-// 
+///////////////////////////////////////////////////////////////////////////////
+//
+// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
+//
+// This code is licensed under the MIT License (MIT).
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+//
 ///////////////////////////////////////////////////////////////////////////////
 
 #pragma once
@@ -19,8 +19,11 @@
 #ifndef GSL_SPAN_H
 #define GSL_SPAN_H
 
+#include "gsl_assert.h"
+#include "gsl_util.h"
 #include <algorithm>
 #include <array>
+#include <cassert>
 #include <cstddef>
 #include <cstdint>
 #include <functional>
@@ -31,14 +34,12 @@
 #include <stdexcept>
 #include <type_traits>
 #include <utility>
-#include <cassert>
-#include "gsl_assert.h"
 
 #ifdef _MSC_VER
 
 // turn off some warnings that are noisy about our Expects statements
 #pragma warning(push)
-#pragma warning(disable: 4127) // conditional expression is constant
+#pragma warning(disable : 4127) // conditional expression is constant
 
 // No MSVC does constexpr fully yet
 #pragma push_macro("constexpr")
@@ -47,19 +48,19 @@
 // VS 2013 workarounds
 #if _MSC_VER <= 1800
 
-// needed in span.h
-#define GSL_MSVC_HAS_VARIADIC_CTOR_BUG 
+#define GSL_MSVC_HAS_VARIADIC_CTOR_BUG
+#define GSL_MSVC_NO_SUPPORT_FOR_MOVE_CTOR_DEFAULT
 
-// noexcept is not understood 
+// noexcept is not understood
 #ifndef GSL_THROWS_ON_CONTRACT_VIOLATION
 #pragma push_macro("noexcept")
-#define noexcept /* nothing */ 
+#define noexcept /* nothing */
 #endif
 
 // turn off some misguided warnings
 #pragma warning(push)
-#pragma warning(disable: 4351) // warns about newly introduced aggregate initializer behavior
-#pragma warning(disable: 4512) // warns that assignment op could not be generated
+#pragma warning(disable : 4351) // warns about newly introduced aggregate initializer behavior
+#pragma warning(disable : 4512) // warns that assignment op could not be generated
 
 #endif // _MSC_VER <= 1800
 
@@ -71,12 +72,12 @@
 #pragma push_macro("noexcept")
 #endif
 
-#define noexcept /* nothing */ 
+#define noexcept /* nothing */
 
-#endif // GSL_THROW_ON_CONTRACT_VIOLATION 
+#endif // GSL_THROW_ON_CONTRACT_VIOLATION
 
-
-namespace gsl {
+namespace gsl
+{
 
 /*
 ** begin definitions of index and bounds
@@ -89,12 +90,17 @@ namespace details
         static const SizeType max_value = std::numeric_limits<SizeType>::max();
     };
 
+    template <typename... Ts>
+    class are_integral : public std::integral_constant<bool, true>
+    {
+    };
 
-    template<typename... Ts>
-    class are_integral : public std::integral_constant<bool, true> {};
-
-    template<typename T, typename... Ts>
-    class are_integral<T, Ts...> : public std::integral_constant<bool, std::is_integral<T>::value && are_integral<Ts...>::value> {};
+    template <typename T, typename... Ts>
+    class are_integral<T, Ts...>
+        : public std::integral_constant<bool,
+                                        std::is_integral<T>::value && are_integral<Ts...>::value>
+    {
+    };
 }
 
 template <size_t Rank>
@@ -112,26 +118,28 @@ public:
     using reference = std::add_lvalue_reference_t<value_type>;
     using const_reference = std::add_lvalue_reference_t<std::add_const_t<value_type>>;
 
-    constexpr index() noexcept
-    {}
+    constexpr index() noexcept {}
 
-    constexpr index(const value_type(&values)[Rank]) noexcept
+    constexpr index(const value_type (&values)[Rank]) noexcept
     {
         std::copy(values, values + Rank, elems);
     }
 
 #ifdef GSL_MSVC_HAS_VARIADIC_CTOR_BUG
-    template<typename T, typename... Ts,
-        typename = std::enable_if_t<((sizeof...(Ts) + 1) == Rank) &&
-        std::is_integral<T>::value &&
-        details::are_integral<Ts...>::value>>
-    constexpr index(T t, Ts... ds) : index({ static_cast<value_type>(t), static_cast<value_type>(ds)... })
-    {}
+    template <
+        typename T, typename... Ts,
+        typename = std::enable_if_t<((sizeof...(Ts) + 1) == Rank) && std::is_integral<T>::value &&
+                                    details::are_integral<Ts...>::value>>
+    constexpr index(T t, Ts... ds)
+        : index({narrow_cast<value_type>(t), narrow_cast<value_type>(ds)...})
+    {
+    }
 #else
-    template<typename... Ts,
-        typename = std::enable_if_t<(sizeof...(Ts) == Rank) && details::are_integral<Ts...>::value>>
-    constexpr index(Ts... ds) noexcept : elems{ static_cast<value_type>(ds)... }
-    {}
+    template <typename... Ts, typename = std::enable_if_t<(sizeof...(Ts) == Rank) &&
+                                                          details::are_integral<Ts...>::value>>
+    constexpr index(Ts... ds) noexcept : elems{narrow_cast<value_type>(ds)...}
+    {
+    }
 #endif
 
     constexpr index(const index& other) noexcept = default;
@@ -157,15 +165,9 @@ public:
         return std::equal(elems, elems + rank, rhs.elems);
     }
 
-    constexpr bool operator!=(const index& rhs) const noexcept
-    {
-        return !(this == rhs);
-    }
+    constexpr bool operator!=(const index& rhs) const noexcept { return !(this == rhs); }
 
-    constexpr index operator+() const noexcept
-    {
-        return *this;
-    }
+    constexpr index operator+() const noexcept { return *this; }
 
     constexpr index operator-() const noexcept
     {
@@ -221,13 +223,15 @@ public:
 
     constexpr index& operator*=(value_type v) noexcept
     {
-        std::transform(elems, elems + rank, elems, [v](value_type x) { return std::multiplies<value_type>{}(x, v); });
+        std::transform(elems, elems + rank, elems,
+                       [v](value_type x) { return std::multiplies<value_type>{}(x, v); });
         return *this;
     }
 
     constexpr index& operator/=(value_type v) noexcept
     {
-        std::transform(elems, elems + rank, elems, [v](value_type x) { return std::divides<value_type>{}(x, v); });
+        std::transform(elems, elems + rank, elems,
+                       [v](value_type x) { return std::divides<value_type>{}(x, v); });
         return *this;
     }
 
@@ -242,31 +246,30 @@ struct static_bounds_dynamic_range_t
     template <typename T, typename Dummy = std::enable_if_t<std::is_integral<T>::value>>
     constexpr operator T() const noexcept
     {
-        return static_cast<T>(-1);
+        return narrow_cast<T>(-1);
     }
 
     template <typename T, typename Dummy = std::enable_if_t<std::is_integral<T>::value>>
-    constexpr bool operator ==(T other) const noexcept
+    constexpr bool operator==(T other) const noexcept
     {
-        return static_cast<T>(-1) == other;
+        return narrow_cast<T>(-1) == other;
     }
 
     template <typename T, typename Dummy = std::enable_if_t<std::is_integral<T>::value>>
-    constexpr bool operator !=(T other) const noexcept
+    constexpr bool operator!=(T other) const noexcept
     {
-        return static_cast<T>(-1) != other;
+        return narrow_cast<T>(-1) != other;
     }
-
 };
 
 template <typename T, typename Dummy = std::enable_if_t<std::is_integral<T>::value>>
-constexpr bool operator ==(T left, static_bounds_dynamic_range_t right) noexcept
+constexpr bool operator==(T left, static_bounds_dynamic_range_t right) noexcept
 {
     return right == left;
 }
 
 template <typename T, typename Dummy = std::enable_if_t<std::is_integral<T>::value>>
-constexpr bool operator !=(T left, static_bounds_dynamic_range_t right) noexcept
+constexpr bool operator!=(T left, static_bounds_dynamic_range_t right) noexcept
 {
     return right != left;
 }
@@ -276,8 +279,12 @@ constexpr static_bounds_dynamic_range_t dynamic_range{};
 const std::ptrdiff_t dynamic_range = -1;
 #endif
 
-struct generalized_mapping_tag {};
-struct contiguous_mapping_tag : generalized_mapping_tag {};
+struct generalized_mapping_tag
+{
+};
+struct contiguous_mapping_tag : generalized_mapping_tag
+{
+};
 
 namespace details
 {
@@ -289,8 +296,9 @@ namespace details
     };
 
     template <std::ptrdiff_t... Ranges>
-    struct BoundsRanges {
-            using size_type = std::ptrdiff_t;
+    struct BoundsRanges
+    {
+        using size_type = std::ptrdiff_t;
         static const size_type Depth = 0;
         static const size_type DynamicNum = 0;
         static const size_type CurrentRange = 1;
@@ -299,54 +307,53 @@ namespace details
         // TODO : following signature is for work around VS bug
         template <typename OtherRange>
         BoundsRanges(const OtherRange&, bool /* firstLevel */)
-        {}
-        
-        BoundsRanges (const BoundsRanges&) = default;
-        BoundsRanges& operator=(const BoundsRanges&) = default;
-        BoundsRanges(const std::ptrdiff_t* const) { }
-        BoundsRanges() = default;
+        {
+        }
 
+        BoundsRanges(const BoundsRanges&) = default;
+        BoundsRanges& operator=(const BoundsRanges&) = default;
+        BoundsRanges(const std::ptrdiff_t* const) {}
+        BoundsRanges() = default;
 
         template <typename T, size_t Dim>
         void serialize(T&) const
-        {}
+        {
+        }
 
         template <typename T, size_t Dim>
         size_type linearize(const T&) const
-        { 
+        {
             return 0;
         }
 
         template <typename T, size_t Dim>
         bool contains(const T&) const
         {
-            return 0;
+            return false;
         }
 
-        size_type totalSize() const noexcept
-        {
-            return TotalSize;
-        }
+        size_type elementNum(size_t) const noexcept { return 0; }
 
-        bool operator==(const BoundsRanges&) const noexcept
-        {
-            return true;
-        }
+        size_type totalSize() const noexcept { return TotalSize; }
+
+        bool operator==(const BoundsRanges&) const noexcept { return true; }
     };
 
     template <std::ptrdiff_t... RestRanges>
-    struct BoundsRanges <dynamic_range, RestRanges...> : BoundsRanges<RestRanges...>{
-        using Base = BoundsRanges <RestRanges... >;
-            using size_type = std::ptrdiff_t;
+    struct BoundsRanges<dynamic_range, RestRanges...> : BoundsRanges<RestRanges...>
+    {
+        using Base = BoundsRanges<RestRanges...>;
+        using size_type = std::ptrdiff_t;
         static const size_t Depth = Base::Depth + 1;
         static const size_t DynamicNum = Base::DynamicNum + 1;
         static const size_type CurrentRange = dynamic_range;
         static const size_type TotalSize = dynamic_range;
         const size_type m_bound;
 
-        BoundsRanges (const BoundsRanges&) = default;
-        
-            BoundsRanges(const std::ptrdiff_t* const arr) : Base(arr + 1), m_bound(*arr * this->Base::totalSize())
+        BoundsRanges(const BoundsRanges&) = default;
+
+        BoundsRanges(const std::ptrdiff_t* const arr)
+            : Base(arr + 1), m_bound(*arr * this->Base::totalSize())
         {
             Expects(0 <= *arr);
         }
@@ -354,9 +361,12 @@ namespace details
         BoundsRanges() : m_bound(0) {}
 
         template <std::ptrdiff_t OtherRange, std::ptrdiff_t... RestOtherRanges>
-            BoundsRanges(const BoundsRanges<OtherRange, RestOtherRanges...>& other, bool /* firstLevel */ = true) :
-                Base(static_cast<const BoundsRanges<RestOtherRanges...>&>(other), false), m_bound(other.totalSize())
-            {}
+        BoundsRanges(const BoundsRanges<OtherRange, RestOtherRanges...>& other,
+                     bool /* firstLevel */ = true)
+            : Base(static_cast<const BoundsRanges<RestOtherRanges...>&>(other), false)
+            , m_bound(other.totalSize())
+        {
+        }
 
         template <typename T, size_t Dim = 0>
         void serialize(T& arr) const
@@ -367,101 +377,24 @@ namespace details
 
         template <typename T, size_t Dim = 0>
         size_type linearize(const T& arr) const
-        { 
+        {
             const size_type index = this->Base::totalSize() * arr[Dim];
             Expects(index < m_bound);
             return index + this->Base::template linearize<T, Dim + 1>(arr);
         }
-        
-        template <typename T, size_t Dim = 0>
-        size_type contains(const T & arr) const
-        {
-            const ptrdiff_t last = this->Base::template contains<T, Dim + 1>(arr);
-            if (last == -1)
-                return -1;
-            const ptrdiff_t cur = this->Base::totalSize() * arr[Dim];
-            return cur < m_bound ? cur + last : -1;
-        }
-        
-        size_type totalSize() const noexcept
-        {
-            return m_bound;
-        }
-        
-        size_type elementNum() const noexcept
-        {
-            return totalSize() / this->Base::totalSize();
-        }
-        
-        size_type elementNum(size_t dim) const noexcept
-        {
-            if (dim > 0)
-                return this->Base::elementNum(dim - 1);
-            else
-                return elementNum();
-        }
-
-        bool operator == (const BoundsRanges & rhs) const noexcept
-        {
-            return m_bound == rhs.m_bound && static_cast<const Base&>(*this) == static_cast<const Base&>(rhs);
-        }
-    };
-
-    template <std::ptrdiff_t CurRange, std::ptrdiff_t... RestRanges>
-    struct BoundsRanges <CurRange, RestRanges...> : BoundsRanges<RestRanges...>
-    {
-        using Base = BoundsRanges <RestRanges... >;
-            using size_type = std::ptrdiff_t;
-        static const size_t Depth = Base::Depth + 1;
-        static const size_t DynamicNum = Base::DynamicNum;
-        static const size_type CurrentRange = CurRange;
-        static const size_type TotalSize = Base::TotalSize == dynamic_range ? dynamic_range : CurrentRange * Base::TotalSize;
-
-        BoundsRanges (const BoundsRanges&) = default;
-        BoundsRanges(const std::ptrdiff_t* const arr) : Base(arr) { }
-        BoundsRanges() = default;
-
-        template <std::ptrdiff_t OtherRange, std::ptrdiff_t... RestOtherRanges>
-        BoundsRanges(const BoundsRanges<OtherRange, RestOtherRanges...>&other, bool firstLevel = true) : Base(static_cast<const BoundsRanges<RestOtherRanges...>&>(other), false)
-        {            
-            Expects((firstLevel && totalSize() <= other.totalSize()) || totalSize() == other.totalSize());
-            (void)firstLevel;
-        }
-
-        template <typename T, size_t Dim = 0>
-        void serialize(T& arr) const
-        {
-            arr[Dim] = elementNum();
-            this->Base::template serialize<T, Dim + 1>(arr);
-        }
-
-        template <typename T, size_t Dim = 0>
-        size_type linearize(const T& arr) const
-        {  
-            Expects(arr[Dim] < CurrentRange); // Index is out of range
-            return this->Base::totalSize() * arr[Dim] + this->Base::template linearize<T, Dim + 1>(arr);
-        }
 
         template <typename T, size_t Dim = 0>
         size_type contains(const T& arr) const
         {
-            if (arr[Dim] >= CurrentRange)
-                return -1;
-            const size_type last = this->Base::template contains<T, Dim + 1>(arr);
-            if (last == -1)
-                return -1;
-            return this->Base::totalSize() * arr[Dim] + last;
+            const ptrdiff_t last = this->Base::template contains<T, Dim + 1>(arr);
+            if (last == -1) return -1;
+            const ptrdiff_t cur = this->Base::totalSize() * arr[Dim];
+            return cur < m_bound ? cur + last : -1;
         }
 
-        size_type totalSize() const noexcept
-        {
-            return CurrentRange * this->Base::totalSize();
-        }
+        size_type totalSize() const noexcept { return m_bound; }
 
-        size_type elementNum() const noexcept
-        {
-            return CurrentRange;
-        }
+        size_type elementNum() const noexcept { return totalSize() / this->Base::totalSize(); }
 
         size_type elementNum(size_t dim) const noexcept
         {
@@ -471,72 +404,126 @@ namespace details
                 return elementNum();
         }
 
-        bool operator== (const BoundsRanges& rhs) const noexcept
+        bool operator==(const BoundsRanges& rhs) const noexcept
         {
-            return static_cast<const Base &>(*this) == static_cast<const Base &>(rhs);
+            return m_bound == rhs.m_bound &&
+                   static_cast<const Base&>(*this) == static_cast<const Base&>(rhs);
         }
     };
 
-    template <typename SourceType, typename TargetType, size_t Rank>
-    struct BoundsRangeConvertible2;
+    template <std::ptrdiff_t CurRange, std::ptrdiff_t... RestRanges>
+    struct BoundsRanges<CurRange, RestRanges...> : BoundsRanges<RestRanges...>
+    {
+        using Base = BoundsRanges<RestRanges...>;
+        using size_type = std::ptrdiff_t;
+        static const size_t Depth = Base::Depth + 1;
+        static const size_t DynamicNum = Base::DynamicNum;
+        static const size_type CurrentRange = CurRange;
+        static const size_type TotalSize =
+            Base::TotalSize == dynamic_range ? dynamic_range : CurrentRange * Base::TotalSize;
 
-    template <size_t Rank, typename SourceType, typename TargetType, typename Ret = BoundsRangeConvertible2<typename SourceType::Base, typename TargetType::Base, Rank>>
-    auto helpBoundsRangeConvertible(SourceType, TargetType, std::true_type) -> Ret;
+        BoundsRanges(const BoundsRanges&) = default;
 
-    template <size_t Rank, typename SourceType, typename TargetType>
-    auto helpBoundsRangeConvertible(SourceType, TargetType, ...) -> std::false_type;
-    
-    template <typename SourceType, typename TargetType, size_t Rank>
-    struct BoundsRangeConvertible2 : decltype(helpBoundsRangeConvertible<Rank - 1>(SourceType(), TargetType(), 
-        std::integral_constant<bool, SourceType::Depth == TargetType::Depth 
-        && (SourceType::CurrentRange == TargetType::CurrentRange || TargetType::CurrentRange == dynamic_range || SourceType::CurrentRange == dynamic_range)>())) 
-    {};
+        BoundsRanges(const std::ptrdiff_t* const arr) : Base(arr) {}
+        BoundsRanges() = default;
+
+        template <std::ptrdiff_t OtherRange, std::ptrdiff_t... RestOtherRanges>
+        BoundsRanges(const BoundsRanges<OtherRange, RestOtherRanges...>& other,
+                     bool firstLevel = true)
+            : Base(static_cast<const BoundsRanges<RestOtherRanges...>&>(other), false)
+        {
+            (void) firstLevel;
+        }
+
+        template <typename T, size_t Dim = 0>
+        void serialize(T& arr) const
+        {
+            arr[Dim] = elementNum();
+            this->Base::template serialize<T, Dim + 1>(arr);
+        }
+
+        template <typename T, size_t Dim = 0>
+        size_type linearize(const T& arr) const
+        {
+            Expects(arr[Dim] < CurrentRange); // Index is out of range
+            return this->Base::totalSize() * arr[Dim] +
+                   this->Base::template linearize<T, Dim + 1>(arr);
+        }
+
+        template <typename T, size_t Dim = 0>
+        size_type contains(const T& arr) const
+        {
+            if (arr[Dim] >= CurrentRange) return -1;
+            const size_type last = this->Base::template contains<T, Dim + 1>(arr);
+            if (last == -1) return -1;
+            return this->Base::totalSize() * arr[Dim] + last;
+        }
+
+        size_type totalSize() const noexcept { return CurrentRange * this->Base::totalSize(); }
+
+        size_type elementNum() const noexcept { return CurrentRange; }
+
+        size_type elementNum(size_t dim) const noexcept
+        {
+            if (dim > 0)
+                return this->Base::elementNum(dim - 1);
+            else
+                return elementNum();
+        }
+
+        bool operator==(const BoundsRanges& rhs) const noexcept
+        {
+            return static_cast<const Base&>(*this) == static_cast<const Base&>(rhs);
+        }
+    };
 
     template <typename SourceType, typename TargetType>
-    struct BoundsRangeConvertible2<SourceType, TargetType, 0> : std::true_type {};
-
-    template <typename SourceType, typename TargetType, std::ptrdiff_t Rank = TargetType::Depth>
-    struct BoundsRangeConvertible : decltype(helpBoundsRangeConvertible<Rank - 1>(SourceType(), TargetType(), 
-        std::integral_constant<bool, SourceType::Depth == TargetType::Depth 
-        && (!LessThan<SourceType::CurrentRange, TargetType::CurrentRange>::value || TargetType::CurrentRange == dynamic_range || SourceType::CurrentRange == dynamic_range)>())) 
-    {};
-    template <typename SourceType, typename TargetType>
-    struct BoundsRangeConvertible<SourceType, TargetType, 0> : std::true_type {};
+    struct BoundsRangeConvertible
+        : public std::integral_constant<bool, (SourceType::TotalSize >= TargetType::TotalSize ||
+                                               TargetType::TotalSize == dynamic_range ||
+                                               SourceType::TotalSize == dynamic_range ||
+                                               TargetType::TotalSize == 0)>
+    {
+    };
 
     template <typename TypeChain>
     struct TypeListIndexer
     {
-        const TypeChain & obj;
-        TypeListIndexer(const TypeChain & obj) :obj(obj){}
-        template<size_t N>
-        const TypeChain & getObj(std::true_type)
-        {
-            return obj;
-        }
-        template<size_t N, typename MyChain = TypeChain, typename MyBase = typename MyChain::Base>
-        auto getObj(std::false_type) -> decltype(TypeListIndexer<MyBase>(static_cast<const MyBase &>(obj)).template get<N>())
-        {
-            return TypeListIndexer<MyBase>(static_cast<const MyBase &>(obj)).template get<N>();
-        }
+        const TypeChain& obj_;
+        TypeListIndexer(const TypeChain& obj) : obj_(obj) {}
+
         template <size_t N>
-        auto get() -> decltype(getObj<N - 1>(std::integral_constant<bool, true>()))
+        const TypeChain& getObj(std::true_type)
+        {
+            return obj_;
+        }
+
+        template <size_t N, typename MyChain = TypeChain, typename MyBase = typename MyChain::Base>
+        auto getObj(std::false_type)
+            -> decltype(TypeListIndexer<MyBase>(static_cast<const MyBase&>(obj_)).template get<N>())
+        {
+            return TypeListIndexer<MyBase>(static_cast<const MyBase&>(obj_)).template get<N>();
+        }
+
+        template <size_t N>
+        auto get() -> decltype(getObj<N - 1>(std::integral_constant<bool, N == 0>()))
         {
             return getObj<N - 1>(std::integral_constant<bool, N == 0>());
         }
     };
 
     template <typename TypeChain>
-    TypeListIndexer<TypeChain> createTypeListIndexer(const TypeChain &obj)
+    TypeListIndexer<TypeChain> createTypeListIndexer(const TypeChain& obj)
     {
         return TypeListIndexer<TypeChain>(obj);
     }
 
-    template <size_t Rank, bool Enabled = (Rank > 1), typename Ret = std::enable_if_t<Enabled, index<Rank - 1>>>
+    template <size_t Rank, bool Enabled = (Rank > 1),
+              typename Ret = std::enable_if_t<Enabled, index<Rank - 1>>>
     constexpr Ret shift_left(const index<Rank>& other) noexcept
     {
         Ret ret{};
-        for (size_t i = 0; i < Rank - 1; ++i)
-        {
+        for (size_t i = 0; i < Rank - 1; ++i) {
             ret[i] = other[i + 1];
         }
         return ret;
@@ -550,19 +537,17 @@ template <std::ptrdiff_t... Ranges>
 class static_bounds
 {
 public:
-    static_bounds(const details::BoundsRanges<Ranges...>&) {
-    }
+    static_bounds(const details::BoundsRanges<Ranges...>&) {}
 };
 
 template <std::ptrdiff_t FirstRange, std::ptrdiff_t... RestRanges>
 class static_bounds<FirstRange, RestRanges...>
 {
-    using MyRanges = details::BoundsRanges<FirstRange, RestRanges... >;
+    using MyRanges = details::BoundsRanges<FirstRange, RestRanges...>;
 
     MyRanges m_ranges;
-    constexpr static_bounds(const MyRanges& range) : m_ranges(range)
-    {}
-    
+    constexpr static_bounds(const MyRanges& range) : m_ranges(range) {}
+
     template <std::ptrdiff_t... OtherRanges>
     friend class static_bounds;
 
@@ -581,94 +566,144 @@ public:
     using mapping_type = contiguous_mapping_tag;
 
     constexpr static_bounds(const static_bounds&) = default;
-    
-    template <std::ptrdiff_t... Ranges, typename Dummy = std::enable_if_t<
-        details::BoundsRangeConvertible<details::BoundsRanges<Ranges...>, details::BoundsRanges <FirstRange, RestRanges... >>::value>>
+
+    template <typename SourceType, typename TargetType, size_t Rank>
+    struct BoundsRangeConvertible2;
+
+    template <size_t Rank, typename SourceType, typename TargetType,
+              typename Ret = BoundsRangeConvertible2<typename SourceType::Base,
+                                                     typename TargetType::Base, Rank>>
+    static auto helpBoundsRangeConvertible(SourceType, TargetType, std::true_type) -> Ret;
+
+    template <size_t Rank, typename SourceType, typename TargetType>
+    static auto helpBoundsRangeConvertible(SourceType, TargetType, ...) -> std::false_type;
+
+    template <typename SourceType, typename TargetType, size_t Rank>
+    struct BoundsRangeConvertible2
+        : decltype(helpBoundsRangeConvertible<Rank - 1>(
+              SourceType(), TargetType(),
+              std::integral_constant<bool,
+                                     SourceType::Depth == TargetType::Depth &&
+                                         (SourceType::CurrentRange == TargetType::CurrentRange ||
+                                          TargetType::CurrentRange == dynamic_range ||
+                                          SourceType::CurrentRange == dynamic_range)>()))
+    {
+    };
+
+    template <typename SourceType, typename TargetType>
+    struct BoundsRangeConvertible2<SourceType, TargetType, 0> : std::true_type
+    {
+    };
+
+    template <typename SourceType, typename TargetType, std::ptrdiff_t Rank = TargetType::Depth>
+    struct BoundsRangeConvertible
+        : decltype(helpBoundsRangeConvertible<Rank - 1>(
+              SourceType(), TargetType(),
+              std::integral_constant<bool,
+                                     SourceType::Depth == TargetType::Depth &&
+                                         (!details::LessThan<SourceType::CurrentRange,
+                                                             TargetType::CurrentRange>::value ||
+                                          TargetType::CurrentRange == dynamic_range ||
+                                          SourceType::CurrentRange == dynamic_range)>()))
+    {
+    };
+
+    template <typename SourceType, typename TargetType>
+    struct BoundsRangeConvertible<SourceType, TargetType, 0> : std::true_type
+    {
+    };
+
+    template <std::ptrdiff_t... Ranges,
+              typename = std::enable_if_t<details::BoundsRangeConvertible<
+                  details::BoundsRanges<Ranges...>,
+                  details::BoundsRanges<FirstRange, RestRanges...>>::value>>
     constexpr static_bounds(const static_bounds<Ranges...>& other) : m_ranges(other.m_ranges)
-    {}
-                                                       
-    constexpr static_bounds(std::initializer_list<size_type> il) : m_ranges((const std::ptrdiff_t*)il.begin())
+    {
+        Expects((MyRanges::DynamicNum == 0 && details::BoundsRanges<Ranges...>::DynamicNum == 0) ||
+                MyRanges::DynamicNum > 0 || other.m_ranges.totalSize() >= m_ranges.totalSize());
+    }
+
+    constexpr static_bounds(std::initializer_list<size_type> il)
+        : m_ranges(static_cast<const std::ptrdiff_t*>(il.begin()))
     {
         // Size of the initializer list must match the rank of the array
-        Expects((MyRanges::DynamicNum == 0 && il.size() == 1 && *il.begin() == static_size) || MyRanges::DynamicNum == il.size()); 
+        Expects((MyRanges::DynamicNum == 0 && il.size() == 1 && *il.begin() == static_size) ||
+                MyRanges::DynamicNum == il.size());
         // Size of the range must be less than the max element of the size type
-        Expects(m_ranges.totalSize() <= PTRDIFF_MAX); 
+        Expects(m_ranges.totalSize() <= PTRDIFF_MAX);
     }
-    
+
     constexpr static_bounds() = default;
 
     constexpr static_bounds& operator=(const static_bounds& otherBounds)
     {
-        new(&m_ranges) MyRanges (otherBounds.m_ranges);
+        new (&m_ranges) MyRanges(otherBounds.m_ranges);
         return *this;
     }
 
     constexpr sliced_type slice() const noexcept
     {
-        return sliced_type{static_cast<const details::BoundsRanges<RestRanges...> &>(m_ranges)};
+        return sliced_type{static_cast<const details::BoundsRanges<RestRanges...>&>(m_ranges)};
     }
 
-    constexpr size_type stride() const noexcept
-    {
-        return rank > 1 ? slice().size() : 1;
-    }
-    
-    constexpr size_type size() const noexcept
-    {
-        return m_ranges.totalSize();
-    }
+    constexpr size_type stride() const noexcept { return rank > 1 ? slice().size() : 1; }
+
+    constexpr size_type size() const noexcept { return m_ranges.totalSize(); }
+
+    constexpr size_type total_size() const noexcept { return m_ranges.totalSize(); }
+
+    constexpr size_type linearize(const index_type& idx) const { return m_ranges.linearize(idx); }
 
-    constexpr size_type total_size() const noexcept
-    {
-        return m_ranges.totalSize();
-    }
-    
-    constexpr size_type linearize(const index_type & idx) const
-    {
-        return m_ranges.linearize(idx);
-    }
-    
     constexpr bool contains(const index_type& idx) const noexcept
     {
         return m_ranges.contains(idx) != -1;
     }
-    
+
     constexpr size_type operator[](size_t index) const noexcept
     {
         return m_ranges.elementNum(index);
     }
-    
+
     template <size_t Dim = 0>
     constexpr size_type extent() const noexcept
     {
-        static_assert(Dim < rank, "dimension should be less than rank (dimension count starts from 0)");
+        static_assert(Dim < rank,
+                      "dimension should be less than rank (dimension count starts from 0)");
         return details::createTypeListIndexer(m_ranges).template get<Dim>().elementNum();
     }
-    
+
+    template <typename IntType>
+    constexpr size_type extent(IntType dim) const noexcept
+    {
+        static_assert(std::is_integral<IntType>::value,
+                      "Dimension parameter must be supplied as an integral type.");
+        auto real_dim = narrow_cast<size_t>(dim);
+        Expects(real_dim < rank);
+
+        return m_ranges.elementNum(real_dim);
+    }
+
     constexpr index_type index_bounds() const noexcept
     {
         size_type extents[rank] = {};
         m_ranges.serialize(extents);
-        return{ extents };
+        return {extents};
     }
-    
+
     template <std::ptrdiff_t... Ranges>
-    constexpr bool operator == (const static_bounds<Ranges...>& rhs) const noexcept
+    constexpr bool operator==(const static_bounds<Ranges...>& rhs) const noexcept
     {
         return this->size() == rhs.size();
     }
-    
+
     template <std::ptrdiff_t... Ranges>
-    constexpr bool operator != (const static_bounds<Ranges...>& rhs) const noexcept
+    constexpr bool operator!=(const static_bounds<Ranges...>& rhs) const noexcept
     {
         return !(*this == rhs);
     }
-    
-    constexpr const_iterator begin() const noexcept
-    {
-        return const_iterator(*this, index_type{});
-    }
-    
+
+    constexpr const_iterator begin() const noexcept { return const_iterator(*this, index_type{}); }
+
     constexpr const_iterator end() const noexcept
     {
         return const_iterator(*this, this->index_bounds());
@@ -676,19 +711,19 @@ public:
 };
 
 template <size_t Rank>
-class strided_bounds 
+class strided_bounds
 {
     template <size_t OtherRank>
     friend class strided_bounds;
 
 public:
     static const size_t rank = Rank;
-    using value_type      = std::ptrdiff_t;
-    using reference       = std::add_lvalue_reference_t<value_type>;
+    using value_type = std::ptrdiff_t;
+    using reference = std::add_lvalue_reference_t<value_type>;
     using const_reference = std::add_const_t<reference>;
-    using size_type       = value_type;
+    using size_type = value_type;
     using difference_type = value_type;
-    using index_type      = index<rank>;
+    using index_type = index<rank>;
     using const_index_type = std::add_const_t<index_type>;
     using iterator = bounds_iterator<const_index_type>;
     using const_iterator = bounds_iterator<const_index_type>;
@@ -697,49 +732,45 @@ public:
     using sliced_type = std::conditional_t<rank != 0, strided_bounds<rank - 1>, void>;
     using mapping_type = generalized_mapping_tag;
 
-    constexpr strided_bounds(const strided_bounds &) noexcept = default;
+    constexpr strided_bounds(const strided_bounds&) noexcept = default;
 
-    constexpr strided_bounds & operator=(const strided_bounds &) noexcept = default;
+    constexpr strided_bounds& operator=(const strided_bounds&) noexcept = default;
 
-    constexpr strided_bounds(const value_type(&values)[rank], index_type strides)
+    constexpr strided_bounds(const value_type (&values)[rank], index_type strides)
         : m_extents(values), m_strides(std::move(strides))
-    {}
-
-    constexpr strided_bounds(const index_type &extents, const index_type &strides) noexcept
-        : m_extents(extents), m_strides(strides)
-    {}
-
-    constexpr index_type strides() const noexcept
     {
-        return m_strides;
     }
 
+    constexpr strided_bounds(const index_type& extents, const index_type& strides) noexcept
+        : m_extents(extents),
+          m_strides(strides)
+    {
+    }
+
+    constexpr index_type strides() const noexcept { return m_strides; }
+
     constexpr size_type total_size() const noexcept
     {
         size_type ret = 0;
-        for (size_t i = 0; i < rank; ++i)
-        {
+        for (size_t i = 0; i < rank; ++i) {
             ret += (m_extents[i] - 1) * m_strides[i];
         }
         return ret + 1;
     }
-    
+
     constexpr size_type size() const noexcept
     {
         size_type ret = 1;
-        for (size_t i = 0; i < rank; ++i)
-        {
+        for (size_t i = 0; i < rank; ++i) {
             ret *= m_extents[i];
         }
         return ret;
     }
-    
+
     constexpr bool contains(const index_type& idx) const noexcept
     {
-        for (size_t i = 0; i < rank; ++i)
-        {
-            if (idx[i] < 0 || idx[i] >= m_extents[i])
-                return false;
+        for (size_t i = 0; i < rank; ++i) {
+            if (idx[i] < 0 || idx[i] >= m_extents[i]) return false;
         }
         return true;
     }
@@ -747,45 +778,33 @@ public:
     constexpr size_type linearize(const index_type& idx) const noexcept
     {
         size_type ret = 0;
-        for (size_t i = 0; i < rank; i++)
-        {
+        for (size_t i = 0; i < rank; i++) {
             Expects(idx[i] < m_extents[i]); // index is out of bounds of the array
             ret += idx[i] * m_strides[i];
         }
         return ret;
     }
-    
-    constexpr size_type stride() const noexcept
-    {
-        return m_strides[0];
-    }
-    
+
+    constexpr size_type stride() const noexcept { return m_strides[0]; }
+
     template <bool Enabled = (rank > 1), typename Ret = std::enable_if_t<Enabled, sliced_type>>
     constexpr sliced_type slice() const
     {
-        return{ details::shift_left(m_extents), details::shift_left(m_strides) };
+        return {details::shift_left(m_extents), details::shift_left(m_strides)};
     }
-    
+
     template <size_t Dim = 0>
     constexpr size_type extent() const noexcept
     {
-        static_assert(Dim < Rank, "dimension should be less than rank (dimension count starts from 0)");
+        static_assert(Dim < Rank,
+                      "dimension should be less than rank (dimension count starts from 0)");
         return m_extents[Dim];
     }
-    
-    constexpr index_type index_bounds() const noexcept
-    {
-        return m_extents;
-    }
-    constexpr const_iterator begin() const noexcept
-    {
-        return const_iterator{ *this, index_type{} };
-    }
-    
-    constexpr const_iterator end() const noexcept
-    {
-        return const_iterator{ *this, index_bounds() };
-    }
+
+    constexpr index_type index_bounds() const noexcept { return m_extents; }
+    constexpr const_iterator begin() const noexcept { return const_iterator{*this, index_type{}}; }
+
+    constexpr const_iterator end() const noexcept { return const_iterator{*this, index_bounds()}; }
 
 private:
     index_type m_extents;
@@ -793,17 +812,23 @@ private:
 };
 
 template <typename T>
-struct is_bounds : std::integral_constant<bool, false> {};
+struct is_bounds : std::integral_constant<bool, false>
+{
+};
 template <std::ptrdiff_t... Ranges>
-struct is_bounds<static_bounds<Ranges...>> : std::integral_constant<bool, true> {};
+struct is_bounds<static_bounds<Ranges...>> : std::integral_constant<bool, true>
+{
+};
 template <size_t Rank>
-struct is_bounds<strided_bounds<Rank>> : std::integral_constant<bool, true> {};
+struct is_bounds<strided_bounds<Rank>> : std::integral_constant<bool, true>
+{
+};
 
 template <typename IndexType>
-class bounds_iterator: public std::iterator<std::random_access_iterator_tag, IndexType>
+class bounds_iterator : public std::iterator<std::random_access_iterator_tag, IndexType>
 {
 private:
-    using Base = std::iterator <std::random_access_iterator_tag, IndexType>;
+    using Base = std::iterator<std::random_access_iterator_tag, IndexType>;
 
 public:
     static const size_t rank = IndexType::rank;
@@ -815,27 +840,20 @@ public:
     using index_size_type = typename IndexType::value_type;
     template <typename Bounds>
     explicit bounds_iterator(const Bounds& bnd, value_type curr) noexcept
-        : boundary(bnd.index_bounds()), curr(std::move(curr))
+        : boundary(bnd.index_bounds()),
+          curr(std::move(curr))
     {
         static_assert(is_bounds<Bounds>::value, "Bounds type must be provided");
     }
 
-    constexpr reference operator*() const noexcept
-    {
-        return curr;
-    }
+    constexpr reference operator*() const noexcept { return curr; }
 
-    constexpr pointer operator->() const noexcept
-    {
-        return &curr;
-    }
+    constexpr pointer operator->() const noexcept { return &curr; }
 
     constexpr bounds_iterator& operator++() noexcept
     {
-        for (size_t i = rank; i-- > 0;)
-        {
-            if (curr[i] < boundary[i] - 1)
-            {
+        for (size_t i = rank; i-- > 0;) {
+            if (curr[i] < boundary[i] - 1) {
                 curr[i]++;
                 return *this;
             }
@@ -855,19 +873,15 @@ public:
 
     constexpr bounds_iterator& operator--() noexcept
     {
-        if (!less(curr, boundary))
-        {
+        if (!less(curr, boundary)) {
             // if at the past-the-end, set to last element
-            for (size_t i = 0; i < rank; ++i)
-            {
+            for (size_t i = 0; i < rank; ++i) {
                 curr[i] = boundary[i] - 1;
             }
             return *this;
         }
-        for (size_t i = rank; i-- > 0;)
-        {
-            if (curr[i] >= 1)
-            {
+        for (size_t i = rank; i-- > 0;) {
+            if (curr[i] >= 1) {
                 curr[i]--;
                 return *this;
             }
@@ -875,7 +889,7 @@ public:
         }
         // If we're here the preconditions were violated
         // "pre: there exists s such that r == ++s"
-        Expects(false); 
+        Expects(false);
         return *this;
     }
 
@@ -888,7 +902,7 @@ public:
 
     constexpr bounds_iterator operator+(difference_type n) const noexcept
     {
-        bounds_iterator ret{ *this };
+        bounds_iterator ret{*this};
         return ret += n;
     }
 
@@ -897,83 +911,62 @@ public:
         auto linear_idx = linearize(curr) + n;
         std::remove_const_t<value_type> stride = 0;
         stride[rank - 1] = 1;
-        for (size_t i = rank - 1; i-- > 0;)
-        {
+        for (size_t i = rank - 1; i-- > 0;) {
             stride[i] = stride[i + 1] * boundary[i + 1];
         }
-        for (size_t i = 0; i < rank; ++i)
-        {
+        for (size_t i = 0; i < rank; ++i) {
             curr[i] = linear_idx / stride[i];
             linear_idx = linear_idx % stride[i];
         }
-        //index is out of bounds of the array
+        // index is out of bounds of the array
         Expects(!less(curr, index_type{}) && !less(boundary, curr));
         return *this;
     }
 
     constexpr bounds_iterator operator-(difference_type n) const noexcept
     {
-        bounds_iterator ret{ *this };
+        bounds_iterator ret{*this};
         return ret -= n;
     }
 
-    constexpr bounds_iterator& operator-=(difference_type n) noexcept
-    {
-        return *this += -n;
-    }
+    constexpr bounds_iterator& operator-=(difference_type n) noexcept { return * this += -n; }
 
     constexpr difference_type operator-(const bounds_iterator& rhs) const noexcept
     {
         return linearize(curr) - linearize(rhs.curr);
     }
 
-    constexpr value_type operator[](difference_type n) const noexcept
-    {
-        return *(*this + n);
-    }
+    constexpr value_type operator[](difference_type n) const noexcept { return *(*this + n); }
 
     constexpr bool operator==(const bounds_iterator& rhs) const noexcept
     {
         return curr == rhs.curr;
     }
 
-    constexpr bool operator!=(const bounds_iterator& rhs) const noexcept
-    {
-        return !(*this == rhs);
-    }
+    constexpr bool operator!=(const bounds_iterator& rhs) const noexcept { return !(*this == rhs); }
 
     constexpr bool operator<(const bounds_iterator& rhs) const noexcept
     {
         return less(curr, rhs.curr);
     }
 
-    constexpr bool operator<=(const bounds_iterator& rhs) const noexcept
-    {
-        return !(rhs < *this);
-    }
+    constexpr bool operator<=(const bounds_iterator& rhs) const noexcept { return !(rhs < *this); }
 
-    constexpr bool operator>(const bounds_iterator& rhs) const noexcept
-    {
-        return rhs < *this;
-    }
+    constexpr bool operator>(const bounds_iterator& rhs) const noexcept { return rhs < *this; }
 
-    constexpr bool operator>=(const bounds_iterator& rhs) const noexcept
-    {
-        return !(rhs > *this);
-    }
+    constexpr bool operator>=(const bounds_iterator& rhs) const noexcept { return !(rhs > *this); }
 
     void swap(bounds_iterator& rhs) noexcept
     {
         std::swap(boundary, rhs.boundary);
         std::swap(curr, rhs.curr);
     }
+
 private:
     constexpr bool less(index_type& one, index_type& other) const noexcept
     {
-        for (size_t i = 0; i < rank; ++i)
-        {
-            if (one[i] < other[i])
-                return true;
+        for (size_t i = 0; i < rank; ++i) {
+            if (one[i] < other[i]) return true;
         }
         return false;
     }
@@ -984,19 +977,16 @@ private:
         // Check if past-the-end
         index_size_type multiplier = 1;
         index_size_type res = 0;
-        if (!less(idx, boundary))
-        {
+        if (!less(idx, boundary)) {
             res = 1;
-            for (size_t i = rank; i-- > 0;)
-            {
+            for (size_t i = rank; i-- > 0;) {
                 res += (idx[i] - 1) * multiplier;
                 multiplier *= boundary[i];
             }
         }
         else
         {
-            for (size_t i = rank; i-- > 0;)
-            {
+            for (size_t i = rank; i-- > 0;) {
                 res += idx[i] * multiplier;
                 multiplier *= boundary[i];
             }
@@ -1009,54 +999,63 @@ private:
 };
 
 template <typename IndexType>
-bounds_iterator<IndexType> operator+(typename bounds_iterator<IndexType>::difference_type n, const bounds_iterator<IndexType>& rhs) noexcept
+bounds_iterator<IndexType> operator+(typename bounds_iterator<IndexType>::difference_type n,
+                                     const bounds_iterator<IndexType>& rhs) noexcept
 {
     return rhs + n;
 }
 
-//
-// begin definitions of basic_span
-//
 namespace details
 {
     template <typename Bounds>
-    constexpr std::enable_if_t<std::is_same<typename Bounds::mapping_type, generalized_mapping_tag>::value, typename Bounds::index_type> make_stride(const Bounds& bnd) noexcept
+    constexpr std::enable_if_t<
+        std::is_same<typename Bounds::mapping_type, generalized_mapping_tag>::value,
+        typename Bounds::index_type>
+    make_stride(const Bounds& bnd) noexcept
     {
         return bnd.strides();
     }
 
     // Make a stride vector from bounds, assuming contiguous memory.
     template <typename Bounds>
-    constexpr std::enable_if_t<std::is_same<typename Bounds::mapping_type, contiguous_mapping_tag>::value, typename Bounds::index_type> make_stride(const Bounds& bnd) noexcept
+    constexpr std::enable_if_t<
+        std::is_same<typename Bounds::mapping_type, contiguous_mapping_tag>::value,
+        typename Bounds::index_type>
+    make_stride(const Bounds& bnd) noexcept
     {
         auto extents = bnd.index_bounds();
         typename Bounds::size_type stride[Bounds::rank] = {};
 
         stride[Bounds::rank - 1] = 1;
-        for (size_t i = 1; i < Bounds::rank; ++i)
-        {
+        for (size_t i = 1; i < Bounds::rank; ++i) {
             stride[Bounds::rank - i - 1] = stride[Bounds::rank - i] * extents[Bounds::rank - i];
         }
-        return{ stride };
+        return {stride};
     }
 
     template <typename BoundsSrc, typename BoundsDest>
-    void verifyBoundsReshape(const BoundsSrc &src, const BoundsDest &dest)
+    void verifyBoundsReshape(const BoundsSrc& src, const BoundsDest& dest)
     {
-        static_assert(is_bounds<BoundsSrc>::value && is_bounds<BoundsDest>::value, "The src type and dest type must be bounds");
-        static_assert(std::is_same<typename BoundsSrc::mapping_type, contiguous_mapping_tag>::value, "The source type must be a contiguous bounds");
-        static_assert(BoundsDest::static_size == dynamic_range || BoundsSrc::static_size == dynamic_range || BoundsDest::static_size == BoundsSrc::static_size, "The source bounds must have same size as dest bounds");
+        static_assert(is_bounds<BoundsSrc>::value && is_bounds<BoundsDest>::value,
+                      "The src type and dest type must be bounds");
+        static_assert(std::is_same<typename BoundsSrc::mapping_type, contiguous_mapping_tag>::value,
+                      "The source type must be a contiguous bounds");
+        static_assert(BoundsDest::static_size == dynamic_range ||
+                          BoundsSrc::static_size == dynamic_range ||
+                          BoundsDest::static_size == BoundsSrc::static_size,
+                      "The source bounds must have same size as dest bounds");
         Expects(src.size() == dest.size());
     }
 
-
 } // namespace details
 
 template <typename Span>
 class contiguous_span_iterator;
 template <typename Span>
 class general_span_iterator;
-enum class byte : std::uint8_t {};
+enum class byte : std::uint8_t
+{
+};
 
 template <std::ptrdiff_t DimSize = dynamic_range>
 struct dim
@@ -1071,7 +1070,8 @@ struct dim<dynamic_range>
     dim(std::ptrdiff_t size) : dvalue(size) {}
 };
 
-template <typename ValueType, std::ptrdiff_t FirstDimension = dynamic_range, std::ptrdiff_t... RestDimensions>
+template <typename ValueType, std::ptrdiff_t FirstDimension = dynamic_range,
+          std::ptrdiff_t... RestDimensions>
 class span;
 
 template <typename ValueType, size_t Rank>
@@ -1087,14 +1087,15 @@ namespace details
     };
 
     template <typename Traits>
-    struct SpanTypeTraits<Traits, typename std::is_reference<typename Traits::span_traits &>::type>
+    struct SpanTypeTraits<Traits, typename std::is_reference<typename Traits::span_traits&>::type>
     {
         using value_type = typename Traits::span_traits::value_type;
         using size_type = typename Traits::span_traits::size_type;
     };
 
     template <typename T, std::ptrdiff_t... Ranks>
-    struct SpanArrayTraits {
+    struct SpanArrayTraits
+    {
         using type = span<T, Ranks...>;
         using value_type = T;
         using bounds_type = static_bounds<Ranks...>;
@@ -1102,46 +1103,53 @@ namespace details
         using reference = T&;
     };
     template <typename T, std::ptrdiff_t N, std::ptrdiff_t... Ranks>
-    struct SpanArrayTraits<T[N], Ranks...> : SpanArrayTraits<T, Ranks..., N> {};
+    struct SpanArrayTraits<T[N], Ranks...> : SpanArrayTraits<T, Ranks..., N>
+    {
+    };
 
     template <typename BoundsType>
     BoundsType newBoundsHelperImpl(std::ptrdiff_t totalSize, std::true_type) // dynamic size
     {
-        Expects(totalSize <= PTRDIFF_MAX);
+        Expects(totalSize >= 0 && totalSize <= PTRDIFF_MAX);
         return BoundsType{totalSize};
     }
     template <typename BoundsType>
     BoundsType newBoundsHelperImpl(std::ptrdiff_t totalSize, std::false_type) // static size
     {
-        Expects(BoundsType::static_size == totalSize);
+        Expects(BoundsType::static_size <= totalSize);
         return {};
     }
     template <typename BoundsType>
     BoundsType newBoundsHelper(std::ptrdiff_t totalSize)
     {
         static_assert(BoundsType::dynamic_rank <= 1, "dynamic rank must less or equal to 1");
-        return newBoundsHelperImpl<BoundsType>(totalSize, std::integral_constant<bool, BoundsType::dynamic_rank == 1>());
+        return newBoundsHelperImpl<BoundsType>(
+            totalSize, std::integral_constant<bool, BoundsType::dynamic_rank == 1>());
     }
-    
-    struct Sep{};
-    
+
+    struct Sep
+    {
+    };
+
     template <typename T, typename... Args>
     T static_as_span_helper(Sep, Args... args)
     {
-        return T{static_cast<typename T::size_type>(args)...};
+        return T{narrow_cast<typename T::size_type>(args)...};
     }
     template <typename T, typename Arg, typename... Args>
-    std::enable_if_t<!std::is_same<Arg, dim<dynamic_range>>::value && !std::is_same<Arg, Sep>::value, T> static_as_span_helper(Arg, Args... args)
+    std::enable_if_t<
+        !std::is_same<Arg, dim<dynamic_range>>::value && !std::is_same<Arg, Sep>::value, T>
+        static_as_span_helper(Arg, Args... args)
     {
         return static_as_span_helper<T>(args...);
     }
     template <typename T, typename... Args>
-    T static_as_span_helper(dim<dynamic_range> val, Args ... args)
+    T static_as_span_helper(dim<dynamic_range> val, Args... args)
     {
         return static_as_span_helper<T>(args..., val.dvalue);
     }
 
-    template <typename ...Dimensions>
+    template <typename... Dimensions>
     struct static_as_span_static_bounds_helper
     {
         using type = static_bounds<(Dimensions::value)...>;
@@ -1149,32 +1157,36 @@ namespace details
 
     template <typename T>
     struct is_span_oracle : std::false_type
-    {};
+    {
+    };
 
     template <typename ValueType, std::ptrdiff_t FirstDimension, std::ptrdiff_t... RestDimensions>
     struct is_span_oracle<span<ValueType, FirstDimension, RestDimensions...>> : std::true_type
-    {};
-    
+    {
+    };
+
     template <typename ValueType, std::ptrdiff_t Rank>
     struct is_span_oracle<strided_span<ValueType, Rank>> : std::true_type
-    {};
-    
+    {
+    };
+
     template <typename T>
     struct is_span : is_span_oracle<std::remove_cv_t<T>>
-    {};
-
+    {
+    };
 }
 
-
 template <typename ValueType, std::ptrdiff_t FirstDimension, std::ptrdiff_t... RestDimensions>
 class span
 {
-    template <typename ValueType2, std::ptrdiff_t FirstDimension2, std::ptrdiff_t... RestDimensions2>
+    // TODO do we still need this?
+    template <typename ValueType2, std::ptrdiff_t FirstDimension2,
+              std::ptrdiff_t... RestDimensions2>
     friend class span;
 
 public:
     using bounds_type = static_bounds<FirstDimension, RestDimensions...>;
-    static const size_t rank = bounds_type::rank;
+    static const size_t Rank = bounds_type::rank;
     using size_type = typename bounds_type::size_type;
     using index_type = typename bounds_type::index_type;
     using value_type = ValueType;
@@ -1186,405 +1198,549 @@ public:
     using const_iterator = contiguous_span_iterator<const_span>;
     using reverse_iterator = std::reverse_iterator<iterator>;
     using const_reverse_iterator = std::reverse_iterator<const_iterator>;
-    using sliced_type = std::conditional_t<rank == 1, value_type, span<value_type, RestDimensions...>>;
+    using sliced_type =
+        std::conditional_t<Rank == 1, value_type, span<value_type, RestDimensions...>>;
 
 private:
-    pointer m_pdata;
-    bounds_type m_bounds;
+    pointer data_;
+    bounds_type bounds_;
 
     friend iterator;
     friend const_iterator;
 
 public:
-
-    constexpr span(pointer data, bounds_type bounds) noexcept
-        : m_pdata(data), m_bounds(std::move(bounds))
+    // default constructor - same as constructing from nullptr_t
+    constexpr span() noexcept : span(nullptr, bounds_type{})
     {
-        Expects((m_bounds.size() > 0 && data != nullptr) || m_bounds.size() == 0);
+        static_assert(bounds_type::dynamic_rank != 0 ||
+                          (bounds_type::dynamic_rank == 0 && bounds_type::static_size == 0),
+                      "Default construction of span<T> only possible "
+                      "for dynamic or fixed, zero-length spans.");
     }
 
-    constexpr span(pointer ptr, size_type size) noexcept
-        : span(ptr, bounds_type{ size })
-    {}
-
-    constexpr span(std::nullptr_t) noexcept
-        : span(nullptr, bounds_type{})
-    {}
-
-    constexpr span(std::nullptr_t, size_type size) noexcept
-        : span(nullptr, bounds_type{})
+    // construct from nullptr - get an empty span
+    constexpr span(std::nullptr_t) noexcept : span(nullptr, bounds_type{})
     {
+        static_assert(bounds_type::dynamic_rank != 0 ||
+                          (bounds_type::dynamic_rank == 0 && bounds_type::static_size == 0),
+                      "nullptr_t construction of span<T> only possible "
+                      "for dynamic or fixed, zero-length spans.");
+    }
+
+    // construct from nullptr with size of 0 (helps with template function calls)
+    template <class IntType, typename = std::enable_if_t<std::is_integral<IntType>::value>>
+    constexpr span(std::nullptr_t, IntType size) noexcept : span(nullptr, bounds_type{})
+    {
+        static_assert(bounds_type::dynamic_rank != 0 ||
+                          (bounds_type::dynamic_rank == 0 && bounds_type::static_size == 0),
+                      "nullptr_t construction of span<T> only possible "
+                      "for dynamic or fixed, zero-length spans.");
         Expects(size == 0);
     }
 
-    // default
-    template <std::ptrdiff_t DynamicRank = bounds_type::dynamic_rank, typename = std::enable_if_t<DynamicRank != 0>>
-    constexpr span() noexcept
-        : span(nullptr, bounds_type())
-    {}
-
-    // from n-dimensions dynamic array (e.g. new int[m][4]) (precedence will be lower than the 1-dimension pointer)
-    template <typename T, typename Helper = details::SpanArrayTraits<T, dynamic_range>,
-        typename Dummy = std::enable_if_t<std::is_same<value_type, std::remove_all_extents_t<T>>::value>
-        /*typename Dummy = std::enable_if_t<std::is_convertible<Helper::value_type (*)[], value_type (*)[]>::value>*/
-    >
-    constexpr span(T* const& data, size_type size) : span(reinterpret_cast<pointer>(data), typename Helper::bounds_type{size})
-    {}
-
-    // from n-dimensions static array
-    template <typename T, size_t N, typename Helper = details::SpanArrayTraits<T, N>,
-        typename = std::enable_if_t<std::is_convertible<typename Helper::value_type(*)[], value_type(*)[]>::value>
-    >
-    constexpr span (T (&arr)[N]) : span(reinterpret_cast<pointer>(arr), typename Helper::bounds_type())
-    {}
-
-    // from n-dimensions static array with size
-    template <typename T, size_t N, typename Helper = details::SpanArrayTraits<T, N>,
-        typename = std::enable_if_t<std::is_convertible<typename Helper::value_type(*)[], value_type(*)[]>::value>
-    >
-    constexpr span(T(&arr)[N], size_type size) : span(arr, typename Helper::bounds_type{size})
+    // construct from a single element
+    constexpr span(reference data) noexcept : span(&data, bounds_type{1})
     {
-        Expects(size <= N);
+        static_assert(bounds_type::dynamic_rank > 0 || bounds_type::static_size == 0 ||
+                          bounds_type::static_size == 1,
+                      "Construction from a single element only possible "
+                      "for dynamic or fixed spans of length 0 or 1.");
     }
 
-    // from std array
-    template <size_t N, 
-       typename Dummy = std::enable_if_t<std::is_convertible<static_bounds<N>, bounds_type>::value>
-    >
-    constexpr span (std::array<std::remove_const_t<value_type>, N> & arr) : span(arr.data(), static_bounds<N>())
-    {}
+    // prevent constructing from temporaries for single-elements
+    constexpr span(value_type&&) = delete;
 
-    template <size_t N,
-        typename Dummy = std::enable_if_t<std::is_convertible<static_bounds<N>, bounds_type>::value
-        && std::is_const<value_type>::value>
-    >
-    constexpr span (const std::array<std::remove_const_t<value_type>, N> & arr) : span(arr.data(), static_bounds<N>())
-    {}
-    
-    // from begin, end pointers. We don't provide iterator pair since no way to guarantee the contiguity 
+    // construct from pointer + length
+    constexpr span(pointer ptr, size_type size) noexcept : span(ptr, bounds_type{size}) {}
+
+    // construct from pointer + length - multidimensional
+    constexpr span(pointer data, bounds_type bounds) noexcept : data_(data),
+                                                                bounds_(std::move(bounds))
+    {
+        Expects((bounds_.size() > 0 && data != nullptr) || bounds_.size() == 0);
+    }
+
+    // construct from begin,end pointer pair
     template <typename Ptr,
-        typename Dummy = std::enable_if_t<std::is_convertible<Ptr, pointer>::value
-        && details::LessThan<bounds_type::dynamic_rank, 2>::value>
-    > // remove literal 0 case
-    constexpr span (pointer begin, Ptr end) : span(begin, details::newBoundsHelper<bounds_type>(static_cast<pointer>(end) - begin))
-    {}
+              typename = std::enable_if_t<std::is_convertible<Ptr, pointer>::value &&
+                                          details::LessThan<bounds_type::dynamic_rank, 2>::value>>
+    constexpr span(pointer begin, Ptr end)
+        : span(begin, details::newBoundsHelper<bounds_type>(static_cast<pointer>(end) - begin))
+    {
+        Expects(begin != nullptr && end != nullptr && begin <= static_cast<pointer>(end));
+    }
 
-    // from containers. It must has .size() and .data() two function signatures
+    // construct from n-dimensions static array
+    template <typename T, size_t N, typename Helper = details::SpanArrayTraits<T, N>>
+    constexpr span(T (&arr)[N])
+        : span(reinterpret_cast<pointer>(arr), bounds_type{typename Helper::bounds_type{}})
+    {
+        static_assert(
+            std::is_convertible<typename Helper::value_type(*) [], value_type(*) []>::value,
+            "Cannot convert from source type to target span type.");
+        static_assert(std::is_convertible<typename Helper::bounds_type, bounds_type>::value,
+                      "Cannot construct a span from an array with fewer elements.");
+    }
+
+    // construct from n-dimensions dynamic array (e.g. new int[m][4])
+    // (precedence will be lower than the 1-dimension pointer)
+    template <typename T, typename Helper = details::SpanArrayTraits<T, dynamic_range>>
+    constexpr span(T* const& data, size_type size)
+        : span(reinterpret_cast<pointer>(data), typename Helper::bounds_type{size})
+    {
+        static_assert(
+            std::is_convertible<typename Helper::value_type(*) [], value_type(*) []>::value,
+            "Cannot convert from source type to target span type.");
+    }
+
+    // construct from std::array
+    template <typename T, size_t N>
+    constexpr span(std::array<T, N>& arr) : span(arr.data(), bounds_type{static_bounds<N>{}})
+    {
+        static_assert(
+            std::is_convertible<T(*) [], typename std::remove_const_t<value_type>(*) []>::value,
+            "Cannot convert from source type to target span type.");
+        static_assert(std::is_convertible<static_bounds<N>, bounds_type>::value,
+                      "You cannot construct a span from a std::array of smaller size.");
+    }
+
+    // construct from const std::array
+    template <typename T, size_t N>
+    constexpr span(const std::array<std::remove_const_t<value_type>, N>& arr)
+        : span(arr.data(), static_bounds<N>())
+    {
+        static_assert(std::is_convertible<T(*) [], std::remove_const_t<value_type>>::value,
+                      "Cannot convert from source type to target span type.");
+        static_assert(std::is_convertible<static_bounds<N>, bounds_type>::value,
+                      "You cannot construct a span from a std::array of smaller size.");
+    }
+
+    // prevent constructing from temporary std::array
+    template <typename T, size_t N>
+    constexpr span(std::array<T, N>&& arr) = delete;
+
+    // construct from containers
+    // future: could use contiguous_iterator_traits to identify only contiguous containers
+    // type-requirements: container must have .size(), operator[] which are value_type compatible
     template <typename Cont, typename DataType = typename Cont::value_type,
-        typename Dummy = std::enable_if_t<!details::is_span<Cont>::value
-        && std::is_convertible<DataType (*)[], value_type (*)[]>::value
-        && std::is_same<std::decay_t<decltype(std::declval<Cont>().size(), *std::declval<Cont>().data())>, DataType>::value>
-    >
-    constexpr span (Cont& cont) : span(static_cast<pointer>(cont.data()), details::newBoundsHelper<bounds_type>(static_cast<size_type>(cont.size())))
-    {}
+              typename = std::enable_if_t<
+                  !details::is_span<Cont>::value &&
+                  std::is_convertible<DataType (*)[], value_type (*)[]>::value &&
+                  std::is_same<std::decay_t<decltype(std::declval<Cont>().size(),
+                                                     *std::declval<Cont>().data())>,
+                               DataType>::value>>
+    constexpr span(Cont& cont)
+        : span(static_cast<pointer>(cont.data()),
+               details::newBoundsHelper<bounds_type>(narrow_cast<size_type>(cont.size())))
+    {
+    }
 
-    constexpr span(const span &) = default;
+    // prevent constructing from temporary containers
+    template <typename Cont, typename DataType = typename Cont::value_type,
+              typename = std::enable_if_t<
+                  !details::is_span<Cont>::value &&
+                  std::is_convertible<DataType (*)[], value_type (*)[]>::value &&
+                  std::is_same<std::decay_t<decltype(std::declval<Cont>().size(),
+                                                     *std::declval<Cont>().data())>,
+                               DataType>::value>>
+    explicit constexpr span(Cont&& cont) = delete;
 
-    // convertible
+    // construct from a convertible span
     template <typename OtherValueType, std::ptrdiff_t... OtherDimensions,
-        typename OtherBounds = static_bounds<OtherDimensions...>,
-        typename Dummy = std::enable_if_t<std::is_convertible<OtherValueType, ValueType>::value && std::is_convertible<OtherBounds, bounds_type>::value>
-    >
-    constexpr span(const span<OtherValueType, OtherDimensions...>& other) noexcept
-        : m_pdata(other.m_pdata), m_bounds(other.m_bounds)
-    {}
-
-    // reshape
-    // DimCount here is a workaround for a bug in MSVC 2015
-    template <typename... Dimensions2, size_t DimCount = sizeof...(Dimensions2), bool Enabled = (DimCount > 0), typename Dummy = std::enable_if_t<Enabled>>
-    constexpr span<ValueType, Dimensions2::value...> as_span(Dimensions2... dims)
+              typename OtherBounds = static_bounds<OtherDimensions...>,
+              typename = std::enable_if_t<std::is_convertible<OtherValueType, ValueType>::value &&
+                                          std::is_convertible<OtherBounds, bounds_type>::value>>
+    constexpr span(span<OtherValueType, OtherDimensions...> other) noexcept : data_(other.data_),
+                                                                              bounds_(other.bounds_)
     {
-        using BoundsType = typename span<ValueType, (Dimensions2::value)...>::bounds_type;
-        auto tobounds = details::static_as_span_helper<BoundsType>(dims..., details::Sep{});
-        details::verifyBoundsReshape(this->bounds(), tobounds);
-        return {this->data(), tobounds};
     }
 
-    // to bytes array
-    template <bool Enabled = std::is_standard_layout<std::decay_t<ValueType>>::value>
-    auto as_bytes() const noexcept -> span<const byte>
-    {
-        static_assert(Enabled, "The value_type of span must be standarded layout");
-        return { reinterpret_cast<const byte*>(this->data()), this->bytes() };
-    }
+// trivial copy and move
+#ifndef GSL_MSVC_NO_SUPPORT_FOR_MOVE_CTOR_DEFAULT
+    constexpr span(span&&) = default;
+#endif
+    constexpr span(const span&) = default;
 
-    template <bool Enabled = std::is_standard_layout<std::decay_t<ValueType>>::value>
-    auto as_writeable_bytes() const noexcept -> span<byte>
-    {
-        static_assert(Enabled, "The value_type of span must be standarded layout");
-        return { reinterpret_cast<byte*>(this->data()), this->bytes() };
-    }
+// trivial assignment
+#ifndef GSL_MSVC_NO_SUPPORT_FOR_MOVE_CTOR_DEFAULT
+    constexpr span& operator=(span&&) = default;
+#endif
+    constexpr span& operator=(const span&) = default;
 
-    // from bytes array
-    template<typename U, bool IsByte = std::is_same<value_type, const byte>::value, typename = std::enable_if_t<IsByte && sizeof...(RestDimensions) == 0>>
-    constexpr auto as_span() const noexcept -> span<const U, (bounds_type::static_size != dynamic_range ? static_cast<std::ptrdiff_t>(static_cast<size_t>(bounds_type::static_size) / sizeof(U)) : dynamic_range)>
-    {
-        static_assert(std::is_standard_layout<U>::value && (bounds_type::static_size == dynamic_range || bounds_type::static_size % static_cast<size_type>(sizeof(U)) == 0),
-            "Target type must be standard layout and its size must match the byte array size");
-        Expects((this->bytes() % sizeof(U)) == 0 && (this->bytes() / sizeof(U)) < PTRDIFF_MAX);
-        return { reinterpret_cast<const U*>(this->data()), this->bytes() / static_cast<size_type>(sizeof(U)) };
-    }
-
-    template<typename U, bool IsByte = std::is_same<value_type, byte>::value, typename = std::enable_if_t<IsByte && sizeof...(RestDimensions) == 0>>
-    constexpr auto as_span() const noexcept -> span<U, (bounds_type::static_size != dynamic_range ? static_cast<ptrdiff_t>(static_cast<size_t>(bounds_type::static_size) / sizeof(U)) : dynamic_range)>
-    {
-        static_assert(std::is_standard_layout<U>::value && (bounds_type::static_size == dynamic_range || bounds_type::static_size % static_cast<size_t>(sizeof(U)) == 0),
-            "Target type must be standard layout and its size must match the byte array size");
-        Expects((this->bytes() % sizeof(U)) == 0);
-        return { reinterpret_cast<U*>(this->data()), this->bytes() / static_cast<size_type>(sizeof(U)) };
-    }
-
-    // section on linear space
-    template<std::ptrdiff_t Count>
+    // first() - extract the first Count elements into a new span
+    template <std::ptrdiff_t Count>
     constexpr span<ValueType, Count> first() const noexcept
     {
-        static_assert(bounds_type::static_size == dynamic_range || Count <= bounds_type::static_size, "Index is out of bound");
-        Expects(bounds_type::static_size != dynamic_range || Count <= this->size()); 
-        return { this->data(), Count };
+        static_assert(Count >= 0, "Count must be >= 0.");
+        static_assert(bounds_type::static_size == dynamic_range ||
+                          Count <= bounds_type::static_size,
+                      "Count is out of bounds.");
+
+        Expects(bounds_type::static_size != dynamic_range || Count <= this->size());
+        return {this->data(), Count};
     }
 
+    // first() - extract the first count elements into a new span
     constexpr span<ValueType, dynamic_range> first(size_type count) const noexcept
     {
-        Expects(count <= this->size());
-        return { this->data(), count };
+        Expects(count >= 0 && count <= this->size());
+        return {this->data(), count};
     }
 
-    template<std::ptrdiff_t Count>
+    // last() - extract the last Count elements into a new span
+    template <std::ptrdiff_t Count>
     constexpr span<ValueType, Count> last() const noexcept
     {
-        static_assert(bounds_type::static_size == dynamic_range || Count <= bounds_type::static_size, "Index is out of bound");
+        static_assert(Count >= 0, "Count must be >= 0.");
+        static_assert(bounds_type::static_size == dynamic_range ||
+                          Count <= bounds_type::static_size,
+                      "Count is out of bounds.");
+
         Expects(bounds_type::static_size != dynamic_range || Count <= this->size());
-        return { this->data() + this->size() - Count, Count };
+        return {this->data() + this->size() - Count, Count};
     }
 
+    // last() - extract the last count elements into a new span
     constexpr span<ValueType, dynamic_range> last(size_type count) const noexcept
     {
-        Expects(count <= this->size());
-        return { this->data() + this->size() - count, count };
+        Expects(count >= 0 && count <= this->size());
+        return {this->data() + this->size() - count, count};
     }
 
-    template<std::ptrdiff_t Offset, std::ptrdiff_t Count>
-    constexpr span<ValueType, Count> sub() const noexcept
+    // subspan() - create a subview of Count elements starting at Offset
+    template <std::ptrdiff_t Offset, std::ptrdiff_t Count>
+    constexpr span<ValueType, Count> subspan() const noexcept
     {
-        static_assert(bounds_type::static_size == dynamic_range || ((Offset == 0 || Offset <= bounds_type::static_size) && Offset + Count <= bounds_type::static_size), "Index is out of bound");
-        Expects(bounds_type::static_size != dynamic_range || ((Offset == 0 || Offset <= this->size()) && Offset + Count <= this->size()));
-        return { this->data() + Offset, Count };
+        static_assert(Count >= 0, "Count must be >= 0.");
+        static_assert(Offset >= 0, "Offset must be >= 0.");
+        static_assert(bounds_type::static_size == dynamic_range ||
+                          ((Offset <= bounds_type::static_size) &&
+                           Count <= bounds_type::static_size - Offset),
+                      "You must describe a sub-range within bounds of the span.");
+
+        Expects(bounds_type::static_size != dynamic_range ||
+                (Offset <= this->size() && Count <= this->size() - Offset));
+        return {this->data() + Offset, Count};
     }
 
-    constexpr span<ValueType, dynamic_range> sub(size_type offset, size_type count = dynamic_range) const noexcept
+    // subspan() - create a subview of count elements starting at offset
+    // supplying dynamic_range for count will consume all available elements from offset
+    constexpr span<ValueType, dynamic_range> subspan(size_type offset,
+                                                     size_type count = dynamic_range) const noexcept
     {
-        Expects((offset == 0 || offset <= this->size()) && (count == dynamic_range || (offset + count) <= this->size()));
-        return { this->data() + offset, count == dynamic_range ? this->length() - offset : count };
+        Expects((offset >= 0 && offset <= this->size()) &&
+                (count == dynamic_range || (count <= this->size() - offset)));
+        return {this->data() + offset, count == dynamic_range ? this->length() - offset : count};
     }
 
-    // size
-    constexpr size_type length() const noexcept
-    {
-        return this->size();
-    }
-
-    constexpr size_type used_length() const noexcept
-    {
-        return length();
-    }
-
-    constexpr size_type bytes() const noexcept
-    {
-        return sizeof(value_type) * this->size();
-    }
-
-    constexpr size_type used_bytes() const noexcept
-    {
-        return bytes();
-    }
-
-    // section
-    constexpr strided_span<ValueType, rank> section(index_type origin, index_type extents) const noexcept
+    // section - creates a non-contiguous, strided span from a contiguous one
+    constexpr strided_span<ValueType, Rank> section(index_type origin, index_type extents) const
+        noexcept
     {
         size_type size = this->bounds().total_size() - this->bounds().linearize(origin);
-        return{ &this->operator[](origin), size, strided_bounds<rank> {extents, details::make_stride(bounds())} };
-    }
-    
-    constexpr reference operator[](const index_type& idx) const noexcept
-    {
-        return m_pdata[m_bounds.linearize(idx)];
-    }
-    
-    template <bool Enabled = (rank > 1), typename Ret = std::enable_if_t<Enabled, sliced_type>>
-    constexpr Ret operator[](size_type idx) const noexcept
-    {
-        Expects(idx < m_bounds.size()); // index is out of bounds of the array
-        const size_type ridx = idx * m_bounds.stride();
-
-        // index is out of bounds of the underlying data
-        Expects(ridx < m_bounds.total_size());
-        return Ret{ m_pdata + ridx, m_bounds.slice() };
+        return {&this->operator[](origin), size,
+                strided_bounds<Rank>{extents, details::make_stride(bounds())}};
     }
 
-    constexpr bounds_type bounds() const noexcept
-    {
-        return m_bounds;
-    }
+    // length of the span in elements
+    constexpr size_type size() const noexcept { return bounds_.size(); }
+
+    // length of the span in elements
+    constexpr size_type length() const noexcept { return this->size(); }
+
+    // length of the span in bytes
+    constexpr size_type size_bytes() const noexcept { return sizeof(value_type) * this->size(); }
+
+    // length of the span in bytes
+    constexpr size_type length_bytes() const noexcept { return this->size_bytes(); }
+
+    constexpr bool empty() const noexcept { return this->size() == 0; }
+
+    static constexpr std::size_t rank() { return Rank; }
 
     template <size_t Dim = 0>
     constexpr size_type extent() const noexcept
     {
-        static_assert(Dim < rank, "dimension should be less than rank (dimension count starts from 0)");
-        return m_bounds.template extent<Dim>();
+        static_assert(Dim < Rank,
+                      "Dimension should be less than rank (dimension count starts from 0).");
+        return bounds_.template extent<Dim>();
     }
 
-    constexpr size_type size() const noexcept
+    template <typename IntType>
+    constexpr size_type extent(IntType dim) const noexcept
     {
-        return m_bounds.size();
+        return bounds_.extent(dim);
     }
 
-    constexpr pointer data() const noexcept
+    constexpr bounds_type bounds() const noexcept { return bounds_; }
+
+    constexpr pointer data() const noexcept { return data_; }
+
+    template <typename FirstIndex>
+    constexpr reference operator()(FirstIndex index)
     {
-        return m_pdata;
+        return this->operator[](narrow_cast<std::ptrdiff_t>(index));
     }
 
-    constexpr explicit operator bool() const noexcept
+    template <typename FirstIndex, typename... OtherIndices>
+    constexpr reference operator()(FirstIndex index, OtherIndices... indices)
     {
-        return m_pdata != nullptr;
+        index_type idx = {narrow_cast<std::ptrdiff_t>(index),
+                          narrow_cast<std::ptrdiff_t>(indices...)};
+        return this->operator[](idx);
     }
 
-    constexpr iterator begin() const noexcept
+    constexpr reference operator[](const index_type& idx) const noexcept
     {
-        return iterator{ this, true };
+        return data_[bounds_.linearize(idx)];
     }
 
-    constexpr iterator end() const noexcept
+    template <bool Enabled = (Rank > 1), typename Ret = std::enable_if_t<Enabled, sliced_type>>
+    constexpr Ret operator[](size_type idx) const noexcept
     {
-        return iterator{ this, false };
+        Expects(idx < bounds_.size()); // index is out of bounds of the array
+        const size_type ridx = idx * bounds_.stride();
+
+        // index is out of bounds of the underlying data
+        Expects(ridx < bounds_.total_size());
+        return Ret{data_ + ridx, bounds_.slice()};
     }
 
+    constexpr iterator begin() const noexcept { return iterator{this, true}; }
+
+    constexpr iterator end() const noexcept { return iterator{this, false}; }
+
     constexpr const_iterator cbegin() const noexcept
     {
-        return const_iterator{ reinterpret_cast<const const_span*>(this), true };
+        return const_iterator{reinterpret_cast<const const_span*>(this), true};
     }
 
     constexpr const_iterator cend() const noexcept
     {
-        return const_iterator{ reinterpret_cast<const const_span*>(this), false };
+        return const_iterator{reinterpret_cast<const const_span*>(this), false};
     }
 
-    constexpr reverse_iterator rbegin() const noexcept
-    {
-        return reverse_iterator{ end() };
-    }
+    constexpr reverse_iterator rbegin() const noexcept { return reverse_iterator{end()}; }
 
-    constexpr reverse_iterator rend() const noexcept
-    {
-        return reverse_iterator{ begin() };
-    }
+    constexpr reverse_iterator rend() const noexcept { return reverse_iterator{begin()}; }
 
     constexpr const_reverse_iterator crbegin() const noexcept
     {
-        return const_reverse_iterator{ cend() };
+        return const_reverse_iterator{cend()};
     }
 
     constexpr const_reverse_iterator crend() const noexcept
     {
-        return const_reverse_iterator{ cbegin() };
+        return const_reverse_iterator{cbegin()};
     }
 
-    template <typename OtherValueType, std::ptrdiff_t... OtherDimensions, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
-    constexpr bool operator== (const span<OtherValueType, OtherDimensions...> & other) const noexcept
+    template <typename OtherValueType, std::ptrdiff_t... OtherDimensions,
+              typename Dummy = std::enable_if_t<std::is_same<
+                  std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
+    constexpr bool operator==(const span<OtherValueType, OtherDimensions...>& other) const noexcept
     {
-        return m_bounds.size() == other.m_bounds.size() &&
-            (m_pdata == other.m_pdata || std::equal(this->begin(), this->end(), other.begin()));
+        return bounds_.size() == other.bounds_.size() &&
+               (data_ == other.data_ || std::equal(this->begin(), this->end(), other.begin()));
     }
 
-    template <typename OtherValueType, std::ptrdiff_t... OtherDimensions, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
-    constexpr bool operator!= (const span<OtherValueType, OtherDimensions...> & other) const noexcept
+    template <typename OtherValueType, std::ptrdiff_t... OtherDimensions,
+              typename Dummy = std::enable_if_t<std::is_same<
+                  std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
+    constexpr bool operator!=(const span<OtherValueType, OtherDimensions...>& other) const noexcept
     {
         return !(*this == other);
     }
 
-    template <typename OtherValueType, std::ptrdiff_t... OtherDimensions, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
-    constexpr bool operator< (const span<OtherValueType, OtherDimensions...> & other) const noexcept
+    template <typename OtherValueType, std::ptrdiff_t... OtherDimensions,
+              typename Dummy = std::enable_if_t<std::is_same<
+                  std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
+    constexpr bool operator<(const span<OtherValueType, OtherDimensions...>& other) const noexcept
     {
         return std::lexicographical_compare(this->begin(), this->end(), other.begin(), other.end());
     }
 
-    template <typename OtherValueType, std::ptrdiff_t... OtherDimensions, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
-    constexpr bool operator<= (const span<OtherValueType, OtherDimensions...> & other) const noexcept
+    template <typename OtherValueType, std::ptrdiff_t... OtherDimensions,
+              typename Dummy = std::enable_if_t<std::is_same<
+                  std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
+    constexpr bool operator<=(const span<OtherValueType, OtherDimensions...>& other) const noexcept
     {
         return !(other < *this);
     }
 
-    template <typename OtherValueType, std::ptrdiff_t... OtherDimensions, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
-    constexpr bool operator> (const span<OtherValueType, OtherDimensions...> & other) const noexcept
+    template <typename OtherValueType, std::ptrdiff_t... OtherDimensions,
+              typename Dummy = std::enable_if_t<std::is_same<
+                  std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
+    constexpr bool operator>(const span<OtherValueType, OtherDimensions...>& other) const noexcept
     {
         return (other < *this);
     }
 
-    template <typename OtherValueType, std::ptrdiff_t... OtherDimensions, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
-    constexpr bool operator>= (const span<OtherValueType, OtherDimensions...> & other) const noexcept
+    template <typename OtherValueType, std::ptrdiff_t... OtherDimensions,
+              typename Dummy = std::enable_if_t<std::is_same<
+                  std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
+    constexpr bool operator>=(const span<OtherValueType, OtherDimensions...>& other) const noexcept
     {
         return !(*this < other);
     }
 };
 
-template <typename T, std::ptrdiff_t... Dimensions>
-constexpr auto as_span(T* const& ptr, dim<Dimensions>... args) -> span<std::remove_all_extents_t<T>, Dimensions...>
+//
+// Free functions for manipulating spans
+//
+
+// reshape a span into a different dimensionality
+// DimCount and Enabled here are workarounds for a bug in MSVC 2015
+template <typename SpanType, typename... Dimensions2, size_t DimCount = sizeof...(Dimensions2),
+          bool Enabled = (DimCount > 0), typename = std::enable_if_t<Enabled>>
+constexpr span<typename SpanType::value_type, Dimensions2::value...> as_span(SpanType s,
+                                                                             Dimensions2... dims)
 {
-    return {reinterpret_cast<std::remove_all_extents_t<T>*>(ptr), details::static_as_span_helper<static_bounds<Dimensions...>>(args..., details::Sep{})};
+    static_assert(details::is_span<SpanType>::value,
+                  "Variadic as_span() is for reshaping existing spans.");
+    using BoundsType =
+        typename span<typename SpanType::value_type, (Dimensions2::value)...>::bounds_type;
+    auto tobounds = details::static_as_span_helper<BoundsType>(dims..., details::Sep{});
+    details::verifyBoundsReshape(s.bounds(), tobounds);
+    return {s.data(), tobounds};
+}
+
+// convert a span<T> to a span<const byte>
+template <typename U, std::ptrdiff_t... Dimensions>
+span<const byte, dynamic_range> as_bytes(span<U, Dimensions...> s) noexcept
+{
+    static_assert(std::is_trivial<std::decay_t<U>>::value,
+                  "The value_type of span must be a trivial type.");
+    return {reinterpret_cast<const byte*>(s.data()), s.size_bytes()};
+}
+
+// convert a span<T> to a span<byte> (a writeable byte span)
+// this is not currently a portable function that can be relied upon to work
+// on all implementations. It should be considered an experimental extension
+// to the standard GSL interface.
+template <typename U, std::ptrdiff_t... Dimensions>
+span<byte> as_writeable_bytes(span<U, Dimensions...> s) noexcept
+{
+    static_assert(std::is_trivial<std::decay_t<U>>::value,
+                  "The value_type of span must be a trivial type.");
+    return {reinterpret_cast<byte*>(s.data()), s.size_bytes()};
+}
+
+// convert a span<const byte> to a span<const T>
+// this is not currently a portable function that can be relied upon to work
+// on all implementations. It should be considered an experimental extension
+// to the standard GSL interface.
+template <typename U, std::ptrdiff_t... Dimensions>
+constexpr auto as_span(span<const byte, Dimensions...> s) noexcept
+    -> span<const U, static_cast<std::ptrdiff_t>(
+                         span<const byte, Dimensions...>::bounds_type::static_size != dynamic_range
+                             ? (static_cast<size_t>(
+                                    span<const byte, Dimensions...>::bounds_type::static_size) /
+                                sizeof(U))
+                             : dynamic_range)>
+{
+    using ConstByteSpan = span<const byte, Dimensions...>;
+    static_assert(
+        std::is_trivial<std::decay_t<U>>::value &&
+            (ConstByteSpan::bounds_type::static_size == dynamic_range ||
+             ConstByteSpan::bounds_type::static_size % narrow_cast<std::ptrdiff_t>(sizeof(U)) == 0),
+        "Target type must be a trivial type and its size must match the byte array size");
+
+    Expects((s.size_bytes() % sizeof(U)) == 0 && (s.size_bytes() / sizeof(U)) < PTRDIFF_MAX);
+    return {reinterpret_cast<const U*>(s.data()),
+            s.size_bytes() / narrow_cast<std::ptrdiff_t>(sizeof(U))};
+}
+
+// convert a span<byte> to a span<T>
+// this is not currently a portable function that can be relied upon to work
+// on all implementations. It should be considered an experimental extension
+// to the standard GSL interface.
+template <typename U, std::ptrdiff_t... Dimensions>
+constexpr auto as_span(span<byte, Dimensions...> s) noexcept -> span<
+    U, narrow_cast<std::ptrdiff_t>(
+           span<byte, Dimensions...>::bounds_type::static_size != dynamic_range
+               ? static_cast<std::size_t>(span<byte, Dimensions...>::bounds_type::static_size) /
+                     sizeof(U)
+               : dynamic_range)>
+{
+    using ByteSpan = span<byte, Dimensions...>;
+    static_assert(
+        std::is_trivial<std::decay_t<U>>::value &&
+            (ByteSpan::bounds_type::static_size == dynamic_range ||
+             ByteSpan::bounds_type::static_size % static_cast<std::size_t>(sizeof(U)) == 0),
+        "Target type must be a trivial type and its size must match the byte array size");
+
+    Expects((s.bytes() % sizeof(U)) == 0);
+    return {reinterpret_cast<U*>(s.data()),
+            s.size_bytes() / narrow_cast<std::ptrdiff_t>(sizeof(U))};
+}
+
+template <typename T, std::ptrdiff_t... Dimensions>
+constexpr auto as_span(T* const& ptr, dim<Dimensions>... args)
+    -> span<std::remove_all_extents_t<T>, Dimensions...>
+{
+    return {reinterpret_cast<std::remove_all_extents_t<T>*>(ptr),
+            details::static_as_span_helper<static_bounds<Dimensions...>>(args..., details::Sep{})};
 }
 
 template <typename T>
-constexpr auto as_span (T* arr, std::ptrdiff_t len) -> typename details::SpanArrayTraits<T, dynamic_range>::type
+constexpr auto as_span(T* arr, std::ptrdiff_t len) ->
+    typename details::SpanArrayTraits<T, dynamic_range>::type
 {
     return {reinterpret_cast<std::remove_all_extents_t<T>*>(arr), len};
 }
 
 template <typename T, size_t N>
-constexpr auto as_span (T (&arr)[N]) -> typename details::SpanArrayTraits<T, N>::type
+constexpr auto as_span(T (&arr)[N]) -> typename details::SpanArrayTraits<T, N>::type
 {
     return {arr};
 }
 
 template <typename T, size_t N>
-constexpr span<const T, N> as_span(const std::array<T, N> &arr)
+constexpr span<const T, N> as_span(const std::array<T, N>& arr)
 {
     return {arr};
 }
 
 template <typename T, size_t N>
-constexpr span<const T, N> as_span(const std::array<T, N> &&) = delete;
+constexpr span<const T, N> as_span(const std::array<T, N>&&) = delete;
 
 template <typename T, size_t N>
-constexpr span<T, N> as_span(std::array<T, N> &arr)
+constexpr span<T, N> as_span(std::array<T, N>& arr)
 {
     return {arr};
 }
 
 template <typename T>
-constexpr span<T, dynamic_range> as_span(T *begin, T *end)
+constexpr span<T, dynamic_range> as_span(T* begin, T* end)
 {
     return {begin, end};
 }
 
 template <typename Cont>
-constexpr auto as_span(Cont &arr) -> std::enable_if_t<!details::is_span<std::decay_t<Cont>>::value,
+constexpr auto as_span(Cont& arr) -> std::enable_if_t<
+    !details::is_span<std::decay_t<Cont>>::value,
     span<std::remove_reference_t<decltype(arr.size(), *arr.data())>, dynamic_range>>
 {
     Expects(arr.size() < PTRDIFF_MAX);
-    return {arr.data(), static_cast<std::ptrdiff_t>(arr.size())};
+    return {arr.data(), narrow_cast<std::ptrdiff_t>(arr.size())};
 }
 
 template <typename Cont>
-constexpr auto as_span(Cont &&arr) -> std::enable_if_t<!details::is_span<std::decay_t<Cont>>::value,
+constexpr auto as_span(Cont&& arr) -> std::enable_if_t<
+    !details::is_span<std::decay_t<Cont>>::value,
     span<std::remove_reference_t<decltype(arr.size(), *arr.data())>, dynamic_range>> = delete;
 
 // from basic_string which doesn't have nonconst .data() member like other contiguous containers
 template <typename CharT, typename Traits, typename Allocator>
-constexpr auto as_span(std::basic_string<CharT, Traits, Allocator> &str) -> span<CharT, dynamic_range>
+constexpr auto as_span(std::basic_string<CharT, Traits, Allocator>& str)
+    -> span<CharT, dynamic_range>
 {
     Expects(str.size() < PTRDIFF_MAX);
-    return {&str[0], static_cast<std::ptrdiff_t>(str.size())};
+    return {&str[0], narrow_cast<std::ptrdiff_t>(str.size())};
 }
 
+// strided_span is an extension that is not strictly part of the GSL at this time.
+// It is kept here while the multidimensional interface is still being defined.
 template <typename ValueType, size_t Rank>
 class strided_span
 {
@@ -1601,11 +1757,12 @@ public:
     using const_iterator = general_span_iterator<const_strided_span>;
     using reverse_iterator = std::reverse_iterator<iterator>;
     using const_reverse_iterator = std::reverse_iterator<const_iterator>;
-    using sliced_type = std::conditional_t<Rank == 1, value_type, strided_span<value_type, Rank-1>>;
+    using sliced_type =
+        std::conditional_t<Rank == 1, value_type, strided_span<value_type, Rank - 1>>;
 
 private:
-    pointer m_pdata;
-    bounds_type m_bounds;
+    pointer data_;
+    bounds_type bounds_;
 
     friend iterator;
     friend const_iterator;
@@ -1615,169 +1772,163 @@ private:
 public:
     // from raw data
     constexpr strided_span(pointer ptr, size_type size, bounds_type bounds)
-        : m_pdata(ptr), m_bounds(std::move(bounds))
+        : data_(ptr), bounds_(std::move(bounds))
     {
-        Expects((m_bounds.size() > 0 && ptr != nullptr) || m_bounds.size() == 0);
+        Expects((bounds_.size() > 0 && ptr != nullptr) || bounds_.size() == 0);
         // Bounds cross data boundaries
         Expects(this->bounds().total_size() <= size);
-        (void)size;
+        (void) size;
     }
 
     // from static array of size N
-    template<size_type N>
-    constexpr strided_span(value_type(&values)[N], bounds_type bounds) : strided_span(values, N, std::move(bounds))
-    {}
+    template <size_type N>
+    constexpr strided_span(value_type (&values)[N], bounds_type bounds)
+        : strided_span(values, N, std::move(bounds))
+    {
+    }
 
     // from array view
     template <typename OtherValueType, std::ptrdiff_t... Dimensions,
-        bool Enabled1 = (sizeof...(Dimensions) == Rank),
-        bool Enabled2 = std::is_convertible<OtherValueType*, ValueType*>::value,
-        typename Dummy = std::enable_if_t<Enabled1 && Enabled2>
-    >
-    constexpr strided_span(span<OtherValueType, Dimensions...> av, bounds_type bounds) : strided_span(av.data(), av.bounds().total_size(), std::move(bounds))
-    {}
-    
+              bool Enabled1 = (sizeof...(Dimensions) == Rank),
+              bool Enabled2 = std::is_convertible<OtherValueType*, ValueType*>::value,
+              typename Dummy = std::enable_if_t<Enabled1 && Enabled2>>
+    constexpr strided_span(span<OtherValueType, Dimensions...> av, bounds_type bounds)
+        : strided_span(av.data(), av.bounds().total_size(), std::move(bounds))
+    {
+    }
+
     // convertible
-    template <typename OtherValueType,
-        typename Dummy = std::enable_if_t<std::is_convertible<OtherValueType(*)[], value_type(*)[]>::value>
-    >
+    template <typename OtherValueType, typename Dummy = std::enable_if_t<std::is_convertible<
+                                           OtherValueType (*)[], value_type (*)[]>::value>>
     constexpr strided_span(const strided_span<OtherValueType, Rank>& other)
-        : m_pdata(other.m_pdata), m_bounds(other.m_bounds)
-    {}
+        : data_(other.data_), bounds_(other.bounds_)
+    {
+    }
 
     // convert from bytes
     template <typename OtherValueType>
-    constexpr strided_span<typename std::enable_if<std::is_same<value_type, const byte>::value, OtherValueType>::type, Rank> as_strided_span() const
+    constexpr strided_span<
+        typename std::enable_if<std::is_same<value_type, const byte>::value, OtherValueType>::type,
+        Rank>
+    as_strided_span() const
     {
-        static_assert((sizeof(OtherValueType) >= sizeof(value_type)) && (sizeof(OtherValueType) % sizeof(value_type) == 0), "OtherValueType should have a size to contain a multiple of ValueTypes");
-        auto d = static_cast<size_type>(sizeof(OtherValueType) / sizeof(value_type));
+        static_assert((sizeof(OtherValueType) >= sizeof(value_type)) &&
+                          (sizeof(OtherValueType) % sizeof(value_type) == 0),
+                      "OtherValueType should have a size to contain a multiple of ValueTypes");
+        auto d = narrow_cast<size_type>(sizeof(OtherValueType) / sizeof(value_type));
 
         size_type size = this->bounds().total_size() / d;
-        return{ (OtherValueType*)this->data(), size, bounds_type{ resize_extent(this->bounds().index_bounds(), d), resize_stride(this->bounds().strides(), d)} };
+        return {(OtherValueType*) this->data(), size,
+                bounds_type{resize_extent(this->bounds().index_bounds(), d),
+                            resize_stride(this->bounds().strides(), d)}};
     }
 
     constexpr strided_span section(index_type origin, index_type extents) const
     {
         size_type size = this->bounds().total_size() - this->bounds().linearize(origin);
-        return { &this->operator[](origin), size, bounds_type {extents, details::make_stride(bounds())}};
+        return {&this->operator[](origin), size,
+                bounds_type{extents, details::make_stride(bounds())}};
     }
 
     constexpr reference operator[](const index_type& idx) const
     {
-        return m_pdata[m_bounds.linearize(idx)];
+        return data_[bounds_.linearize(idx)];
     }
 
     template <bool Enabled = (Rank > 1), typename Ret = std::enable_if_t<Enabled, sliced_type>>
     constexpr Ret operator[](size_type idx) const
     {
-        Expects(idx < m_bounds.size()); // index is out of bounds of the array
-        const size_type ridx = idx * m_bounds.stride();
+        Expects(idx < bounds_.size()); // index is out of bounds of the array
+        const size_type ridx = idx * bounds_.stride();
 
         // index is out of bounds of the underlying data
-        Expects(ridx < m_bounds.total_size());
-        return{ m_pdata + ridx, m_bounds.slice().total_size(), m_bounds.slice() };
+        Expects(ridx < bounds_.total_size());
+        return {data_ + ridx, bounds_.slice().total_size(), bounds_.slice()};
     }
 
-    constexpr bounds_type bounds() const noexcept
-    {
-        return m_bounds;
-    }
+    constexpr bounds_type bounds() const noexcept { return bounds_; }
 
     template <size_t Dim = 0>
     constexpr size_type extent() const noexcept
     {
-        static_assert(Dim < Rank, "dimension should be less than Rank (dimension count starts from 0)");
-        return m_bounds.template extent<Dim>();
+        static_assert(Dim < Rank,
+                      "dimension should be less than Rank (dimension count starts from 0)");
+        return bounds_.template extent<Dim>();
     }
 
-    constexpr size_type size() const noexcept
-    {
-        return m_bounds.size();
-    }
+    constexpr size_type size() const noexcept { return bounds_.size(); }
 
-    constexpr pointer data() const noexcept
-    {
-        return m_pdata;
-    }
+    constexpr pointer data() const noexcept { return data_; }
 
-    constexpr explicit operator bool() const noexcept
-    {
-        return m_pdata != nullptr;
-    }
+    constexpr explicit operator bool() const noexcept { return data_ != nullptr; }
 
-    constexpr iterator begin() const
-    {
-        return iterator{ this, true };
-    }
+    constexpr iterator begin() const { return iterator{this, true}; }
 
-    constexpr iterator end() const
-    {
-        return iterator{ this, false };
-    }
+    constexpr iterator end() const { return iterator{this, false}; }
 
     constexpr const_iterator cbegin() const
     {
-        return const_iterator{ reinterpret_cast<const const_strided_span*>(this), true };
+        return const_iterator{reinterpret_cast<const const_strided_span*>(this), true};
     }
 
     constexpr const_iterator cend() const
     {
-        return const_iterator{ reinterpret_cast<const const_strided_span*>(this), false };
+        return const_iterator{reinterpret_cast<const const_strided_span*>(this), false};
     }
 
-    constexpr reverse_iterator rbegin() const
+    constexpr reverse_iterator rbegin() const { return reverse_iterator{end()}; }
+
+    constexpr reverse_iterator rend() const { return reverse_iterator{begin()}; }
+
+    constexpr const_reverse_iterator crbegin() const { return const_reverse_iterator{cend()}; }
+
+    constexpr const_reverse_iterator crend() const { return const_reverse_iterator{cbegin()}; }
+
+    template <typename OtherValueType, std::ptrdiff_t OtherRank,
+              typename Dummy = std::enable_if_t<std::is_same<
+                  std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
+    constexpr bool operator==(const strided_span<OtherValueType, OtherRank>& other) const noexcept
     {
-        return reverse_iterator{ end() };
+        return bounds_.size() == other.bounds_.size() &&
+               (data_ == other.data_ || std::equal(this->begin(), this->end(), other.begin()));
     }
 
-    constexpr reverse_iterator rend() const
-    {
-        return reverse_iterator{ begin() };
-    }
-
-    constexpr const_reverse_iterator crbegin() const
-    {
-        return const_reverse_iterator{ cend() };
-    }
-
-    constexpr const_reverse_iterator crend() const
-    {
-        return const_reverse_iterator{ cbegin() };
-    }
-
-    template <typename OtherValueType, std::ptrdiff_t OtherRank, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
-    constexpr bool operator== (const strided_span<OtherValueType, OtherRank>& other) const noexcept
-    {
-        return m_bounds.size() == other.m_bounds.size() &&
-            (m_pdata == other.m_pdata || std::equal(this->begin(), this->end(), other.begin()));
-    }
-
-    template <typename OtherValueType, std::ptrdiff_t OtherRank, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
-    constexpr bool operator!= (const strided_span<OtherValueType, OtherRank>& other) const noexcept
+    template <typename OtherValueType, std::ptrdiff_t OtherRank,
+              typename Dummy = std::enable_if_t<std::is_same<
+                  std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
+    constexpr bool operator!=(const strided_span<OtherValueType, OtherRank>& other) const noexcept
     {
         return !(*this == other);
     }
 
-    template <typename OtherValueType, std::ptrdiff_t OtherRank, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
-    constexpr bool operator< (const strided_span<OtherValueType, OtherRank>& other) const noexcept
+    template <typename OtherValueType, std::ptrdiff_t OtherRank,
+              typename Dummy = std::enable_if_t<std::is_same<
+                  std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
+    constexpr bool operator<(const strided_span<OtherValueType, OtherRank>& other) const noexcept
     {
         return std::lexicographical_compare(this->begin(), this->end(), other.begin(), other.end());
     }
 
-    template <typename OtherValueType, std::ptrdiff_t OtherRank, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
-    constexpr bool operator<= (const strided_span<OtherValueType, OtherRank>& other) const noexcept
+    template <typename OtherValueType, std::ptrdiff_t OtherRank,
+              typename Dummy = std::enable_if_t<std::is_same<
+                  std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
+    constexpr bool operator<=(const strided_span<OtherValueType, OtherRank>& other) const noexcept
     {
         return !(other < *this);
     }
 
-    template <typename OtherValueType, std::ptrdiff_t OtherRank, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
-    constexpr bool operator> (const strided_span<OtherValueType, OtherRank>& other) const noexcept
+    template <typename OtherValueType, std::ptrdiff_t OtherRank,
+              typename Dummy = std::enable_if_t<std::is_same<
+                  std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
+    constexpr bool operator>(const strided_span<OtherValueType, OtherRank>& other) const noexcept
     {
         return (other < *this);
     }
 
-    template <typename OtherValueType, std::ptrdiff_t OtherRank, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
-    constexpr bool operator>= (const strided_span<OtherValueType, OtherRank>& other) const noexcept
+    template <typename OtherValueType, std::ptrdiff_t OtherRank,
+              typename Dummy = std::enable_if_t<std::is_same<
+                  std::remove_cv_t<value_type>, std::remove_cv_t<OtherValueType>>::value>>
+    constexpr bool operator>=(const strided_span<OtherValueType, OtherRank>& other) const noexcept
     {
         return !(*this < other);
     }
@@ -1795,7 +1946,7 @@ private:
     }
 
     template <bool Enabled = (Rank == 1), typename Dummy = std::enable_if_t<Enabled>>
-    static index_type resize_stride(const index_type& strides, std::ptrdiff_t , void * = 0)
+    static index_type resize_stride(const index_type& strides, std::ptrdiff_t, void* = 0)
     {
         // Only strided arrays with regular strides can be resized
         Expects(strides[Rank - 1] == 1);
@@ -1812,8 +1963,7 @@ private:
         // memory that can contain a multiple of new type elements
         Expects(strides[Rank - 2] >= d && (strides[Rank - 2] % d == 0));
 
-        for (size_t i = Rank - 1; i > 0; --i)
-        {
+        for (size_t i = Rank - 1; i > 0; --i) {
             // Only strided arrays with regular strides can be resized
             Expects((strides[i - 1] >= strides[i]) && (strides[i - 1] % strides[i] == 0));
         }
@@ -1826,9 +1976,11 @@ private:
 };
 
 template <class Span>
-class contiguous_span_iterator : public std::iterator<std::random_access_iterator_tag, typename Span::value_type>
+class contiguous_span_iterator
+    : public std::iterator<std::random_access_iterator_tag, typename Span::value_type>
 {
     using Base = std::iterator<std::random_access_iterator_tag, typename Span::value_type>;
+
 public:
     using typename Base::reference;
     using typename Base::pointer;
@@ -1838,33 +1990,36 @@ private:
     template <typename ValueType, std::ptrdiff_t FirstDimension, std::ptrdiff_t... RestDimensions>
     friend class span;
 
-    pointer m_pdata;
+    pointer data_;
     const Span* m_validator;
     void validateThis() const
     {
         // iterator is out of range of the array
-        Expects(m_pdata >= m_validator->m_pdata &&
-            m_pdata < m_validator->m_pdata + m_validator->size());
+        Expects(data_ >= m_validator->data_ && data_ < m_validator->data_ + m_validator->size());
     }
-    contiguous_span_iterator (const Span* container, bool isbegin) :
-        m_pdata(isbegin ? container->m_pdata : container->m_pdata + container->size()), m_validator(container) {}
+    contiguous_span_iterator(const Span* container, bool isbegin)
+        : data_(isbegin ? container->data_ : container->data_ + container->size())
+        , m_validator(container)
+    {
+    }
+
 public:
     reference operator*() const noexcept
     {
         validateThis();
-        return *m_pdata;
+        return *data_;
     }
     pointer operator->() const noexcept
     {
         validateThis();
-        return m_pdata;
+        return data_;
     }
     contiguous_span_iterator& operator++() noexcept
     {
-        ++m_pdata;
+        ++data_;
         return *this;
     }
-    contiguous_span_iterator operator++(int)noexcept
+    contiguous_span_iterator operator++(int) noexcept
     {
         auto ret = *this;
         ++(*this);
@@ -1872,10 +2027,10 @@ public:
     }
     contiguous_span_iterator& operator--() noexcept
     {
-        --m_pdata;
+        --data_;
         return *this;
     }
-    contiguous_span_iterator operator--(int)noexcept
+    contiguous_span_iterator operator--(int) noexcept
     {
         auto ret = *this;
         --(*this);
@@ -1883,104 +2038,87 @@ public:
     }
     contiguous_span_iterator operator+(difference_type n) const noexcept
     {
-        contiguous_span_iterator ret{ *this };
+        contiguous_span_iterator ret{*this};
         return ret += n;
     }
     contiguous_span_iterator& operator+=(difference_type n) noexcept
     {
-        m_pdata += n;
+        data_ += n;
         return *this;
     }
     contiguous_span_iterator operator-(difference_type n) const noexcept
     {
-        contiguous_span_iterator ret{ *this };
+        contiguous_span_iterator ret{*this};
         return ret -= n;
     }
-    contiguous_span_iterator& operator-=(difference_type n) noexcept
-    {
-        return *this += -n;
-    }
+    contiguous_span_iterator& operator-=(difference_type n) noexcept { return * this += -n; }
     difference_type operator-(const contiguous_span_iterator& rhs) const noexcept
     {
         Expects(m_validator == rhs.m_validator);
-        return m_pdata - rhs.m_pdata;
-    }
-    reference operator[](difference_type n) const noexcept
-    {
-        return *(*this + n);
+        return data_ - rhs.data_;
     }
+    reference operator[](difference_type n) const noexcept { return *(*this + n); }
     bool operator==(const contiguous_span_iterator& rhs) const noexcept
     {
         Expects(m_validator == rhs.m_validator);
-        return m_pdata == rhs.m_pdata;
-    }
-    bool operator!=(const contiguous_span_iterator& rhs) const noexcept
-    {
-        return !(*this == rhs);
+        return data_ == rhs.data_;
     }
+    bool operator!=(const contiguous_span_iterator& rhs) const noexcept { return !(*this == rhs); }
     bool operator<(const contiguous_span_iterator& rhs) const noexcept
     {
         Expects(m_validator == rhs.m_validator);
-        return m_pdata < rhs.m_pdata;
-    }
-    bool operator<=(const contiguous_span_iterator& rhs) const noexcept
-    {
-        return !(rhs < *this);
-    }
-    bool operator>(const contiguous_span_iterator& rhs) const noexcept
-    {
-        return rhs < *this;
-    }
-    bool operator>=(const contiguous_span_iterator& rhs) const noexcept
-    {
-        return !(rhs > *this);
+        return data_ < rhs.data_;
     }
+    bool operator<=(const contiguous_span_iterator& rhs) const noexcept { return !(rhs < *this); }
+    bool operator>(const contiguous_span_iterator& rhs) const noexcept { return rhs < *this; }
+    bool operator>=(const contiguous_span_iterator& rhs) const noexcept { return !(rhs > *this); }
     void swap(contiguous_span_iterator& rhs) noexcept
     {
-        std::swap(m_pdata, rhs.m_pdata);
+        std::swap(data_, rhs.data_);
         std::swap(m_validator, rhs.m_validator);
     }
 };
 
 template <typename Span>
-contiguous_span_iterator<Span> operator+(typename contiguous_span_iterator<Span>::difference_type n, const contiguous_span_iterator<Span>& rhs) noexcept
+contiguous_span_iterator<Span> operator+(typename contiguous_span_iterator<Span>::difference_type n,
+                                         const contiguous_span_iterator<Span>& rhs) noexcept
 {
     return rhs + n;
 }
 
 template <typename Span>
-class general_span_iterator : public std::iterator<std::random_access_iterator_tag, typename Span::value_type>
+class general_span_iterator
+    : public std::iterator<std::random_access_iterator_tag, typename Span::value_type>
 {
     using Base = std::iterator<std::random_access_iterator_tag, typename Span::value_type>;
+
 public:
     using typename Base::reference;
     using typename Base::pointer;
     using typename Base::difference_type;
     using typename Base::value_type;
+
 private:
     template <typename ValueType, size_t Rank>
     friend class strided_span;
-    
+
     const Span* m_container;
     typename Span::bounds_type::iterator m_itr;
-    general_span_iterator(const Span* container, bool isbegin) :
-        m_container(container), m_itr(isbegin ? m_container->bounds().begin() : m_container->bounds().end())
-    {}
+    general_span_iterator(const Span* container, bool isbegin)
+        : m_container(container)
+        , m_itr(isbegin ? m_container->bounds().begin() : m_container->bounds().end())
+    {
+    }
+
 public:
-    reference operator*() noexcept
-    {
-        return (*m_container)[*m_itr];
-    }
-    pointer operator->() noexcept
-    {
-        return &(*m_container)[*m_itr];
-    }
+    reference operator*() noexcept { return (*m_container)[*m_itr]; }
+    pointer operator->() noexcept { return &(*m_container)[*m_itr]; }
     general_span_iterator& operator++() noexcept
     {
         ++m_itr;
         return *this;
     }
-    general_span_iterator operator++(int)noexcept
+    general_span_iterator operator++(int) noexcept
     {
         auto ret = *this;
         ++(*this);
@@ -1991,7 +2129,7 @@ public:
         --m_itr;
         return *this;
     }
-    general_span_iterator operator--(int)noexcept
+    general_span_iterator operator--(int) noexcept
     {
         auto ret = *this;
         --(*this);
@@ -1999,7 +2137,7 @@ public:
     }
     general_span_iterator operator+(difference_type n) const noexcept
     {
-        general_span_iterator ret{ *this };
+        general_span_iterator ret{*this};
         return ret += n;
     }
     general_span_iterator& operator+=(difference_type n) noexcept
@@ -2009,13 +2147,10 @@ public:
     }
     general_span_iterator operator-(difference_type n) const noexcept
     {
-        general_span_iterator ret{ *this };
+        general_span_iterator ret{*this};
         return ret -= n;
     }
-    general_span_iterator& operator-=(difference_type n) noexcept
-    {
-        return *this += -n;
-    }
+    general_span_iterator& operator-=(difference_type n) noexcept { return * this += -n; }
     difference_type operator-(const general_span_iterator& rhs) const noexcept
     {
         Expects(m_container == rhs.m_container);
@@ -2023,34 +2158,23 @@ public:
     }
     value_type operator[](difference_type n) const noexcept
     {
-        return (*m_container)[m_itr[n]];;
+        return (*m_container)[m_itr[n]];
+        ;
     }
     bool operator==(const general_span_iterator& rhs) const noexcept
     {
         Expects(m_container == rhs.m_container);
         return m_itr == rhs.m_itr;
     }
-    bool operator !=(const general_span_iterator& rhs) const noexcept
-    {
-        return !(*this == rhs);
-    }
+    bool operator!=(const general_span_iterator& rhs) const noexcept { return !(*this == rhs); }
     bool operator<(const general_span_iterator& rhs) const noexcept
     {
         Expects(m_container == rhs.m_container);
         return m_itr < rhs.m_itr;
     }
-    bool operator<=(const general_span_iterator& rhs) const noexcept
-    {
-        return !(rhs < *this);
-    }
-    bool operator>(const general_span_iterator& rhs) const noexcept
-    {
-        return rhs < *this;
-    }
-    bool operator>=(const general_span_iterator& rhs) const noexcept
-    {
-        return !(rhs > *this);
-    }
+    bool operator<=(const general_span_iterator& rhs) const noexcept { return !(rhs < *this); }
+    bool operator>(const general_span_iterator& rhs) const noexcept { return rhs < *this; }
+    bool operator>=(const general_span_iterator& rhs) const noexcept { return !(rhs > *this); }
     void swap(general_span_iterator& rhs) noexcept
     {
         std::swap(m_itr, rhs.m_itr);
@@ -2059,14 +2183,14 @@ public:
 };
 
 template <typename Span>
-general_span_iterator<Span> operator+(typename general_span_iterator<Span>::difference_type n, const general_span_iterator<Span>& rhs) noexcept
+general_span_iterator<Span> operator+(typename general_span_iterator<Span>::difference_type n,
+                                      const general_span_iterator<Span>& rhs) noexcept
 {
     return rhs + n;
 }
 
 } // namespace gsl
 
-
 #ifdef _MSC_VER
 
 #undef constexpr
@@ -2080,13 +2204,13 @@ general_span_iterator<Span> operator+(typename general_span_iterator<Span>::diff
 #pragma pop_macro("noexcept")
 #endif // GSL_THROW_ON_CONTRACT_VIOLATION
 
-#undef GSL_MSVC_HAS_VARIADIC_CTOR_BUG 
+#undef GSL_MSVC_HAS_VARIADIC_CTOR_BUG
 
 #endif // _MSC_VER <= 1800
 
 #endif // _MSC_VER
 
-#if defined(GSL_THROW_ON_CONTRACT_VIOLATION) 
+#if defined(GSL_THROW_ON_CONTRACT_VIOLATION)
 
 #undef noexcept
 
@@ -2095,7 +2219,6 @@ general_span_iterator<Span> operator+(typename general_span_iterator<Span>::diff
 #pragma pop_macro("noexcept")
 #endif
 
-#endif // GSL_THROW_ON_CONTRACT_VIOLATION 
-
+#endif // GSL_THROW_ON_CONTRACT_VIOLATION
 
 #endif // GSL_SPAN_H
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index a524d01..7990ec3 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -45,6 +45,7 @@ function(add_gsl_test name)
 endfunction()
 
 add_gsl_test(span_tests)
+add_gsl_test(strided_span_tests)
 add_gsl_test(string_span_tests)
 add_gsl_test(at_tests)
 add_gsl_test(bounds_tests)
diff --git a/tests/span_tests.cpp b/tests/span_tests.cpp
index e5078af..8737db9 100644
--- a/tests/span_tests.cpp
+++ b/tests/span_tests.cpp
@@ -1,1827 +1,1679 @@
-/////////////////////////////////////////////////////////////////////////////// 
-// 
-// Copyright (c) 2015 Microsoft Corporation. All rights reserved. 
-// 
-// This code is licensed under the MIT License (MIT). 
-// 
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 
-// THE SOFTWARE. 
-// 
+///////////////////////////////////////////////////////////////////////////////
+//
+// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
+//
+// This code is licensed under the MIT License (MIT).
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+//
 ///////////////////////////////////////////////////////////////////////////////
 
-#include <UnitTest++/UnitTest++.h> 
+#include <UnitTest++/UnitTest++.h>
 #include <span.h>
 
+#include <iostream>
+#include <list>
+#include <map>
+#include <memory>
 #include <string>
 #include <vector>
-#include <list>
-#include <iostream>
 
 using namespace std;
 using namespace gsl;
 
-namespace 
+namespace
 {
-	struct BaseClass {};
-	struct DerivedClass : BaseClass {};
+struct BaseClass
+{
+};
+struct DerivedClass : BaseClass
+{
+};
 }
 
 SUITE(span_tests)
 {
-	TEST(basics)
-	{
-		auto ptr = as_span(new int[10], 10);
-		fill(ptr.begin(), ptr.end(), 99);
-		for (int num : ptr)
-		{
-			CHECK(num == 99);
-		}
 
-		delete[] ptr.data();
+    TEST(default_constructor)
+    {
+        {
+            span<int> s;
+            CHECK(s.length() == 0 && s.data() == nullptr);
 
+            span<const int> cs;
+            CHECK(cs.length() == 0 && cs.data() == nullptr);
+        }
 
-		static_bounds<4, dynamic_range, 2> bounds{ 3 };
-	
+        {
+            span<int, 0> s;
+            CHECK(s.length() == 0 && s.data() == nullptr);
+
+            span<const int, 0> cs;
+            CHECK(cs.length() == 0 && cs.data() == nullptr);
+        }
+
+        {
 #ifdef CONFIRM_COMPILATION_ERRORS
-		span<int, 4, dynamic_range, 2> av(nullptr, bounds);
-		av.extent();
-		av.extent<2>();
-		av[8][4][3];
+            span<int, 1> s;
+            CHECK(s.length() == 1 && s.data() == nullptr); // explains why it can't compile
 #endif
-	}
+        }
 
-	TEST (span_convertible)
-	{
+        {
+            span<int> s{};
+            CHECK(s.length() == 0 && s.data() == nullptr);
+
+            span<const int> cs{};
+            CHECK(cs.length() == 0 && cs.data() == nullptr);
+        }
+    }
+
+    TEST(from_nullptr_constructor)
+    {
+        {
+            span<int> s = nullptr;
+            CHECK(s.length() == 0 && s.data() == nullptr);
+
+            span<const int> cs = nullptr;
+            CHECK(cs.length() == 0 && cs.data() == nullptr);
+        }
+
+        {
+            span<int, 0> s = nullptr;
+            CHECK(s.length() == 0 && s.data() == nullptr);
+
+            span<const int, 0> cs = nullptr;
+            CHECK(cs.length() == 0 && cs.data() == nullptr);
+        }
+
+        {
 #ifdef CONFIRM_COMPILATION_ERRORS
-		span<int, 7, 4, 2> av1(nullptr, b1);
+            span<int, 1> s = nullptr;
+            CHECK(s.length() == 1 && s.data() == nullptr); // explains why it can't compile
+#endif
+        }
+
+        {
+            span<int> s{nullptr};
+            CHECK(s.length() == 0 && s.data() == nullptr);
+
+            span<const int> cs{nullptr};
+            CHECK(cs.length() == 0 && cs.data() == nullptr);
+        }
+
+        {
+            span<int*> s{nullptr};
+            CHECK(s.length() == 0 && s.data() == nullptr);
+
+            span<const int*> cs{nullptr};
+            CHECK(cs.length() == 0 && cs.data() == nullptr);
+        }
+    }
+
+    TEST(from_nullptr_length_constructor)
+    {
+        {
+            span<int> s{nullptr, 0};
+            CHECK(s.length() == 0 && s.data() == nullptr);
+
+            span<const int> cs{nullptr, 0};
+            CHECK(cs.length() == 0 && cs.data() == nullptr);
+        }
+
+        {
+            span<int, 0> s{nullptr, 0};
+            CHECK(s.length() == 0 && s.data() == nullptr);
+
+            span<const int, 0> cs{nullptr, 0};
+            CHECK(cs.length() == 0 && cs.data() == nullptr);
+        }
+
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            span<int, 1> s{nullptr, 0};
+            CHECK(s.length() == 1 && s.data() == nullptr); // explains why it can't compile
+#endif
+        }
+
+        {
+            auto workaround_macro = []() { span<int> s{nullptr, 1}; };
+            CHECK_THROW(workaround_macro(), fail_fast);
+
+            auto const_workaround_macro = []() { span<const int> cs{nullptr, 1}; };
+            CHECK_THROW(const_workaround_macro(), fail_fast);
+        }
+
+        {
+            auto workaround_macro = []() { span<int, 0> s{nullptr, 1}; };
+            CHECK_THROW(workaround_macro(), fail_fast);
+
+            auto const_workaround_macro = []() { span<const int, 0> s{nullptr, 1}; };
+            CHECK_THROW(const_workaround_macro(), fail_fast);
+        }
+
+        {
+            span<int*> s{nullptr, 0};
+            CHECK(s.length() == 0 && s.data() == nullptr);
+
+            span<const int*> cs{nullptr, 0};
+            CHECK(cs.length() == 0 && cs.data() == nullptr);
+        }
+    }
+
+    TEST(from_element_constructor)
+    {
+        int i = 5;
+
+        {
+            span<int> s = i;
+            CHECK(s.length() == 1 && s.data() == &i);
+            CHECK(s[0] == 5);
+
+            span<const int> cs = i;
+            CHECK(cs.length() == 1 && cs.data() == &i);
+            CHECK(cs[0] == 5);
+        }
+
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            const j = 1;
+            span<int, 0> s = j;
+#endif
+        }
+
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            span<int, 0> s = i;
+            CHECK(s.length() == 0 && s.data() == &i);
+#endif
+        }
+
+        {
+            span<int, 1> s = i;
+            CHECK(s.length() == 1 && s.data() == &i);
+            CHECK(s[0] == 5);
+        }
+
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            span<int, 2> s = i;
+            CHECK(s.length() == 2 && s.data() == &i);
+#endif
+        }
+
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            auto get_a_temp = []() -> int { return 4; };
+            auto use_a_span = [](span<int> s) { (void) s; };
+            use_a_span(get_a_temp());
+#endif
+        }
+    }
+
+    TEST(from_pointer_length_constructor)
+    {
+        int arr[4] = {1, 2, 3, 4};
+
+        {
+            span<int> s{&arr[0], 2};
+            CHECK(s.length() == 2 && s.data() == &arr[0]);
+            CHECK(s[0] == 1 && s[1] == 2);
+        }
+
+        {
+            span<int, 2> s{&arr[0], 2};
+            CHECK(s.length() == 2 && s.data() == &arr[0]);
+            CHECK(s[0] == 1 && s[1] == 2);
+        }
+
+        {
+            int* p = nullptr;
+            span<int> s{p, 0};
+            CHECK(s.length() == 0 && s.data() == nullptr);
+        }
+
+        {
+            int* p = nullptr;
+            auto workaround_macro = [=]() { span<int> s{p, 2}; };
+            CHECK_THROW(workaround_macro(), fail_fast);
+        }
+    }
+
+    TEST(from_pointer_pointer_constructor)
+    {
+        int arr[4] = {1, 2, 3, 4};
+
+        {
+            span<int> s{&arr[0], &arr[2]};
+            CHECK(s.length() == 2 && s.data() == &arr[0]);
+            CHECK(s[0] == 1 && s[1] == 2);
+        }
+
+        {
+            span<int, 2> s{&arr[0], &arr[2]};
+            CHECK(s.length() == 2 && s.data() == &arr[0]);
+            CHECK(s[0] == 1 && s[1] == 2);
+        }
+
+        {
+            span<int> s{&arr[0], &arr[0]};
+            CHECK(s.length() == 0 && s.data() == &arr[0]);
+        }
+
+        {
+            span<int, 0> s{&arr[0], &arr[0]};
+            CHECK(s.length() == 0 && s.data() == &arr[0]);
+        }
+
+        {
+            auto workaround_macro = [&]() { span<int> s{&arr[1], &arr[0]}; };
+            CHECK_THROW(workaround_macro(), fail_fast);
+        }
+
+        {
+            int* p = nullptr;
+            auto workaround_macro = [&]() { span<int> s{&arr[0], p}; };
+            CHECK_THROW(workaround_macro(), fail_fast);
+        }
+
+        {
+            int* p = nullptr;
+            auto workaround_macro = [&]() { span<int> s{p, p}; };
+            CHECK_THROW(workaround_macro(), fail_fast);
+        }
+
+        {
+            int* p = nullptr;
+            auto workaround_macro = [&]() { span<int> s{&arr[0], p}; };
+            CHECK_THROW(workaround_macro(), fail_fast);
+        }
+    }
+
+    TEST(from_array_constructor)
+    {
+        int arr[5] = {1, 2, 3, 4, 5};
+
+        {
+            span<int> s{arr};
+            CHECK(s.length() == 5 && s.data() == &arr[0]);
+        }
+
+        {
+            span<int, 5> s{arr};
+            CHECK(s.length() == 5 && s.data() == &arr[0]);
+        }
+
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            span<int, 6> s{arr};
+#endif
+        }
+
+        {
+            span<int, 0> s{arr};
+            CHECK(s.length() == 0 && s.data() == &arr[0]);
+        }
+
+        int arr2d[2][3] = {1, 2, 3, 4, 5, 6};
+
+        {
+            span<int> s{arr2d};
+            CHECK(s.length() == 6 && s.data() == &arr2d[0][0]);
+            CHECK(s[0] == 1 && s[5] == 6);
+        }
+
+        {
+            span<int, 0> s{arr2d};
+            CHECK(s.length() == 0 && s.data() == &arr2d[0][0]);
+        }
+
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            span<int, 5> s{arr2d};
+#endif
+        }
+
+        {
+            span<int, 6> s{arr2d};
+            CHECK(s.length() == 6 && s.data() == &arr2d[0][0]);
+            CHECK(s[0] == 1 && s[5] == 6);
+        }
+
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            span<int, 7> s{arr2d};
+#endif
+        }
+
+        {
+            span<int[3]> s{arr2d[0]};
+            CHECK(s.length() == 1 && s.data() == &arr2d[0]);
+        }
+
+        {
+            span<int, 2, 3> s{arr2d};
+            CHECK(s.length() == 6 && s.data() == &arr2d[0][0]);
+            auto workaround_macro = [&]() { return s[{1, 2}] == 6; };
+            CHECK(workaround_macro());
+        }
+
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            span<int, 3, 3> s{arr2d};
+#endif
+        }
+
+        int arr3d[2][3][2] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12};
+
+        {
+            span<int> s{arr3d};
+            CHECK(s.length() == 12 && s.data() == &arr3d[0][0][0]);
+            CHECK(s[0] == 1 && s[11] == 12);
+        }
+
+        {
+            span<int, 0> s{arr3d};
+            CHECK(s.length() == 0 && s.data() == &arr3d[0][0][0]);
+        }
+
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            span<int, 11> s{arr3d};
+#endif
+        }
+
+        {
+            span<int, 12> s{arr3d};
+            CHECK(s.length() == 12 && s.data() == &arr3d[0][0][0]);
+            CHECK(s[0] == 1 && s[5] == 6);
+        }
+
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            span<int, 13> s{arr3d};
+#endif
+        }
+
+        {
+            span<int[3][2]> s{arr3d[0]};
+            CHECK(s.length() == 1 && s.data() == &arr3d[0]);
+        }
+
+        {
+            span<int, 3, 2, 2> s{arr3d};
+            CHECK(s.length() == 12 && s.data() == &arr3d[0][0][0]);
+            auto workaround_macro = [&]() { return s[{2, 1, 0}] == 11; };
+            CHECK(workaround_macro());
+        }
+
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            span<int, 3, 3, 3> s{arr3d};
+#endif
+        }
+    }
+
+    TEST(from_dynamic_array_constructor)
+    {
+        double(*arr)[3][4] = new double[100][3][4];
+
+        {
+            span<double, dynamic_range, 3, 4> s(arr, 10);
+            CHECK(s.length() == 120 && s.data() == &arr[0][0][0]);
+            CHECK_THROW(s[10][3][4], fail_fast);
+        }
+
+        {
+            span<double, dynamic_range, 4, 3> s(arr, 10);
+            CHECK(s.length() == 120 && s.data() == &arr[0][0][0]);
+        }
+
+        {
+            span<double> s(arr, 10);
+            CHECK(s.length() == 120 && s.data() == &arr[0][0][0]);
+        }
+
+        {
+            span<double, dynamic_range, 3, 4> s(arr, 0);
+            CHECK(s.length() == 0 && s.data() == &arr[0][0][0]);
+        }
+
+        delete[] arr;
+    }
+
+    TEST(from_std_array_constructor)
+    {
+        std::array<int, 4> arr = {1, 2, 3, 4};
+
+        {
+            span<int> s{arr};
+            CHECK(s.size() == narrow_cast<ptrdiff_t>(arr.size()) && s.data() == arr.data());
+
+            span<const int> cs{arr};
+            CHECK(cs.size() == narrow_cast<ptrdiff_t>(arr.size()) && cs.data() == arr.data());
+        }
+
+        {
+            span<int, 4> s{arr};
+            CHECK(s.size() == narrow_cast<ptrdiff_t>(arr.size()) && s.data() == arr.data());
+
+            span<const int, 4> cs{arr};
+            CHECK(cs.size() == narrow_cast<ptrdiff_t>(arr.size()) && cs.data() == arr.data());
+        }
+
+        {
+            span<int, 2> s{arr};
+            CHECK(s.size() == 2 && s.data() == arr.data());
+
+            span<const int, 2> cs{arr};
+            CHECK(cs.size() == 2 && cs.data() == arr.data());
+        }
+
+        {
+            span<int, 0> s{arr};
+            CHECK(s.size() == 0 && s.data() == arr.data());
+
+            span<const int, 0> cs{arr};
+            CHECK(cs.size() == 0 && cs.data() == arr.data());
+        }
+
+        // TODO This is currently an unsupported scenario. We will come back to it as we revise
+        // the multidimensional interface and what transformations between dimensionality look like
+        //{
+        //    span<int, 2, 2> s{arr};
+        //    CHECK(s.size() == narrow_cast<ptrdiff_t>(arr.size()) && s.data() == arr.data());
+        //}
+
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            span<int, 5> s{arr};
+#endif
+        }
+
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            auto get_an_array = []() { return std::array<int, 4>{1, 2, 3, 4}; };
+            auto take_a_span = [](span<int> s) { (void) s; };
+            // try to take a temporary std::array
+            take_a_span(get_an_array());
+#endif
+        }
+    }
+
+    TEST(from_const_std_array_constructor)
+    {
+        const std::array<int, 4> arr = {1, 2, 3, 4};
+
+        {
+            span<const int> s{arr};
+            CHECK(s.size() == narrow_cast<ptrdiff_t>(arr.size()) && s.data() == arr.data());
+        }
+
+        {
+            span<const int, 4> s{arr};
+            CHECK(s.size() == narrow_cast<ptrdiff_t>(arr.size()) && s.data() == arr.data());
+        }
+
+        {
+            span<const int, 2> s{arr};
+            CHECK(s.size() == 2 && s.data() == arr.data());
+        }
+
+        {
+            span<const int, 0> s{arr};
+            CHECK(s.size() == 0 && s.data() == arr.data());
+        }
+
+        // TODO This is currently an unsupported scenario. We will come back to it as we revise
+        // the multidimensional interface and what transformations between dimensionality look like
+        //{
+        //    span<int, 2, 2> s{arr};
+        //    CHECK(s.size() == narrow_cast<ptrdiff_t>(arr.size()) && s.data() == arr.data());
+        //}
+
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            span<const int, 5> s{arr};
+#endif
+        }
+
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            auto get_an_array = []() -> const std::array<int, 4> { return {1, 2, 3, 4}; };
+            auto take_a_span = [](span<const int> s) { (void) s; };
+            // try to take a temporary std::array
+            take_a_span(get_an_array());
+#endif
+        }
+    }
+
+    TEST(from_container_constructor)
+    {
+        std::vector<int> v = {1, 2, 3};
+        const std::vector<int> cv = v;
+
+        {
+            span<int> s{v};
+            CHECK(s.size() == narrow_cast<std::ptrdiff_t>(v.size()) && s.data() == v.data());
+
+            span<const int> cs{v};
+            CHECK(cs.size() == narrow_cast<std::ptrdiff_t>(v.size()) && cs.data() == v.data());
+        }
+
+        std::string str = "hello";
+        const std::string cstr = "hello";
+
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            span<char> s{str};
+            CHECK(s.size() == narrow_cast<std::ptrdiff_t>(str.size()) && s.data() == str.data());
+#endif
+            span<const char> cs{str};
+            CHECK(cs.size() == narrow_cast<std::ptrdiff_t>(str.size()) && cs.data() == str.data());
+        }
+
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            span<char> s{cstr};
+#endif
+            span<const char> cs{cstr};
+            CHECK(cs.size() == narrow_cast<std::ptrdiff_t>(cstr.size()) &&
+                  cs.data() == cstr.data());
+        }
+
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            auto get_temp_vector = []() -> std::vector<int> { return {}; };
+            auto use_span = [](span<int> s) { (void) s; };
+            use_span(get_temp_vector());
+#endif
+        }
+
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            auto get_temp_string = []() -> std::string { return {}; };
+            auto use_span = [](span<char> s) { (void) s; };
+            use_span(get_temp_string());
+#endif
+        }
+
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            auto get_temp_vector = []() -> const std::vector<int> { return {}; };
+            auto use_span = [](span<const char> s) { (void) s; };
+            use_span(get_temp_vector());
+#endif
+        }
+
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            auto get_temp_string = []() -> const std::string { return {}; };
+            auto use_span = [](span<const char> s) { (void) s; };
+            use_span(get_temp_string());
+#endif
+        }
+
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            std::map<int, int> m;
+            span<int> s{m};
+#endif
+        }
+    }
+
+    TEST(from_convertible_span_constructor)
+    {
+#ifdef CONFIRM_COMPILATION_ERRORS
+        span<int, 7, 4, 2> av1(nullptr, b1);
+
+        auto f = [&]() { span<int, 7, 4, 2> av1(nullptr); };
+        CHECK_THROW(f(), fail_fast);
 #endif
-	
-		auto f = [&]() { span<int, 7, 4, 2> av1(nullptr); };
-		CHECK_THROW(f(), fail_fast); 
-		
-		span<int, 7, dynamic_range, 2> av1(nullptr);
 
 #ifdef CONFIRM_COMPILATION_ERRORS
-		static_bounds<size_t, 7, dynamic_range, 2> b12(b11);
-		b12 = b11;
-		b11 = b12;
-	
-		span<int, dynamic_range> av1 = nullptr;
-		span<int, 7, dynamic_range, 2> av2(av1);
-		span<int, 7, 4, 2> av2(av1);
+        static_bounds<size_t, 7, dynamic_range, 2> b12(b11);
+        b12 = b11;
+        b11 = b12;
+
+        span<int, dynamic_range> av1 = nullptr;
+        span<int, 7, dynamic_range, 2> av2(av1);
+        span<int, 7, 4, 2> av2(av1);
 #endif
 
-		span<DerivedClass> avd;
+        span<DerivedClass> avd;
 #ifdef CONFIRM_COMPILATION_ERRORS
-		span<BaseClass> avb = avd;
+        span<BaseClass> avb = avd;
 #endif
-		span<const DerivedClass> avcd = avd;
-		(void)avcd;
-	}
+        span<const DerivedClass> avcd = avd;
+        (void) avcd;
+    }
 
-	TEST(boundary_checks)
-	{
-		int arr[10][2];
-		auto av = as_span(arr);
+    TEST(copy_move_and_assignment)
+    {
+        span<int> s1;
+        CHECK(s1.empty());
 
-		fill(begin(av), end(av), 0);
+        int arr[] = {3, 4, 5};
 
-		av[2][0] = 1;
-		av[1][1] = 3;
+        span<const int> s2 = arr;
+        CHECK(s2.length() == 3 && s2.data() == &arr[0]);
 
-		// out of bounds
-		CHECK_THROW(av[1][3] = 3, fail_fast);
-		CHECK_THROW((av[{1, 3}] = 3), fail_fast);
+        s2 = s1;
+        CHECK(s2.empty());
 
-		CHECK_THROW(av[10][2], fail_fast);
-		CHECK_THROW((av[{10,2}]), fail_fast);
-	}
+        auto get_temp_span = [&]() -> span<int> { return {&arr[1], 2}; };
+        auto use_span = [&](span<const int> s) { CHECK(s.length() == 2 && s.data() == &arr[1]); };
+        use_span(get_temp_span());
 
-	void overloaded_func(span<const int, dynamic_range, 3, 5> exp, int expected_value) {
-		for (auto val : exp)
-		{
-			CHECK(val == expected_value);
-		}
-	}
+        s1 = get_temp_span();
+        CHECK(s1.length() == 2 && s1.data() == &arr[1]);
+    }
 
-	void overloaded_func(span<const char, dynamic_range, 3, 5> exp, char expected_value) {
-		for (auto val : exp)
-		{
-			CHECK(val == expected_value);
-		}
-	}
+    template <class Bounds>
+    void fn(const Bounds&)
+    {
+        static_assert(Bounds::static_size == 60, "static bounds is wrong size");
+    }
+    TEST(as_span_reshape)
+    {
+        int a[3][4][5];
+        auto av = as_span(a);
+        fn(av.bounds());
+        auto av2 = as_span(av, dim<60>());
+        auto av3 = as_span(av2, dim<3>(), dim<4>(), dim<5>());
+        auto av4 = as_span(av3, dim<4>(), dim<>(3), dim<5>());
+        auto av5 = as_span(av4, dim<3>(), dim<4>(), dim<5>());
+        auto av6 = as_span(av5, dim<12>(), dim<>(5));
 
-	void fixed_func(span<int, 3, 3, 5> exp, int expected_value) {
-		for (auto val : exp)
-		{
-			CHECK(val == expected_value);
-		}
-	}
+        fill(av6.begin(), av6.end(), 1);
 
-	TEST(span_parameter_test)
-	{
-		auto data = new int[4][3][5];
+        auto av7 = as_bytes(av6);
 
-		auto av = as_span(data, 4);
+        auto av8 = as_span<int>(av7);
 
-		CHECK(av.size() == 60);
+        CHECK(av8.size() == av6.size());
+        for (auto i = 0; i < av8.size(); i++) {
+            CHECK(av8[i] == 1);
+        }
+    }
 
-		fill(av.begin(), av.end(), 34);
-					
-		int count = 0;
-		for_each(av.rbegin(), av.rend(), [&](int val) { count += val; });
-		CHECK(count == 34 * 60);
-		overloaded_func(av, 34);
+    TEST(first)
+    {
+        int arr[5] = {1, 2, 3, 4, 5};
 
-		overloaded_func(av.as_span(dim<>(4), dim<>(3), dim<>(5)), 34);
+        {
+            span<int, 5> av = arr;
+            CHECK((av.first<2>().bounds() == static_bounds<2>()));
+            CHECK(av.first<2>().length() == 2);
+            CHECK(av.first(2).length() == 2);
+        }
 
-		//fixed_func(av, 34);
-		delete[] data;
-	}
+        {
+            span<int, 5> av = arr;
+            CHECK((av.first<0>().bounds() == static_bounds<0>()));
+            CHECK(av.first<0>().length() == 0);
+            CHECK(av.first(0).length() == 0);
+        }
 
+        {
+            span<int, 5> av = arr;
+            CHECK((av.first<5>().bounds() == static_bounds<5>()));
+            CHECK(av.first<5>().length() == 5);
+            CHECK(av.first(5).length() == 5);
+        }
 
-	TEST(md_access)
-	{
-		auto width = 5, height = 20;
-
-		auto imgSize = width * height;
-		auto image_ptr = new int[imgSize][3];
-
-		// size check will be done
-		auto image_view = as_span(image_ptr, imgSize).as_span(dim<>(height), dim<>(width), dim<3>());
-
-		iota(image_view.begin(), image_view.end(), 1);
-
-		int expected = 0;
-		for (auto i = 0; i < height; i++)
-		{
-			for (auto j = 0; j < width; j++)
-			{
-				CHECK(expected + 1 == image_view[i][j][0]);
-				CHECK(expected + 2 == image_view[i][j][1]);
-				CHECK(expected + 3 == image_view[i][j][2]);
-				
-				auto val = image_view[{i, j, 0}];
-				CHECK(expected + 1 == val);
-				val = image_view[{i, j, 1}];
-				CHECK(expected + 2 == val);
-				val = image_view[{i, j, 2}];
-				CHECK(expected + 3 == val);
-
-				expected += 3;
-			}
-		}
-	}
-
-	TEST(span_factory_test)
-	{
-		{
-			int * arr = new int[150];
-
-			auto av = as_span(arr, dim<10>(), dim<>(3), dim<5>());
-
-			fill(av.begin(), av.end(), 24);
-			overloaded_func(av, 24);
-
-			delete[] arr;
-
-
-			array<int, 15> stdarr{ 0 };
-			auto av2 = as_span(stdarr);
-			overloaded_func(av2.as_span(dim<>(1), dim<3>(), dim<5>()), 0);
-
-
-			string str = "ttttttttttttttt"; // size = 15
-			auto t = str.data();
-            (void)t;
-			auto av3 = as_span(str);
-			overloaded_func(av3.as_span(dim<>(1), dim<3>(), dim<5>()), 't');
-		}
-
-		{
-			string str;
-			span<char> strspan = as_span(str);
-			(void)strspan;
-			const string cstr;
-			span<const char> cstrspan = as_span(cstr);
-			(void)cstrspan;
-		}
-
-		{
-			int a[3][4][5];
-			auto av = as_span(a);
-			const int (*b)[4][5];
-			b = a;
-			auto bv = as_span(b, 3);
-
-			CHECK(av == bv);
-
-			const std::array<double, 3> arr = {0.0, 0.0, 0.0};
-			auto cv = as_span(arr);
-			(void)cv;
-
-			vector<float> vec(3);
-			auto dv = as_span(vec);
-			(void)dv;
-			
+        {
+            span<int, 5> av = arr;
 #ifdef CONFIRM_COMPILATION_ERRORS
-			auto dv2 = as_span(std::move(vec));
+            CHECK(av.first<6>().bounds() == static_bounds<6>());
+            CHECK(av.first<6>().length() == 6);
+            CHECK(av.first<-1>().length() == -1);
 #endif
-		}
-	}
-	
-	template <class Bounds> void fn(const Bounds&) { static_assert(Bounds::static_size == 60, "static bounds is wrong size"); }
-	TEST (span_reshape_test)
-	{
-		int a[3][4][5];
-		auto av = as_span(a);
-    	fn(av.bounds());
-		auto av2 = av.as_span(dim<60>());
-		auto av3 = av2.as_span(dim<3>(), dim<4>(), dim<5>());
-		auto av4 = av3.as_span(dim<4>(), dim<>(3), dim<5>());
-		auto av5 = av4.as_span(dim<3>(), dim<4>(), dim<5>());
-		auto av6 = av5.as_span(dim<12>(), dim<>(5));
-		
-		fill(av6.begin(), av6.end(), 1);
-		
-		auto av7 = av6.as_bytes();
-		
-		auto av8 = av7.as_span<int>();
+            CHECK_THROW(av.first(6).length(), fail_fast);
+        }
 
-		CHECK(av8.size() == av6.size());
-		for (auto i = 0; i < av8.size(); i++)
-		{
-			CHECK(av8[i] == 1);
-		}
+        {
+            span<int, dynamic_range> av;
+            CHECK((av.first<0>().bounds() == static_bounds<0>()));
+            CHECK(av.first<0>().length() == 0);
+            CHECK(av.first(0).length() == 0);
+        }
+    }
 
+    TEST(last)
+    {
+        int arr[5] = {1, 2, 3, 4, 5};
+
+        {
+            span<int, 5> av = arr;
+            CHECK((av.last<2>().bounds() == static_bounds<2>()));
+            CHECK(av.last<2>().length() == 2);
+            CHECK(av.last(2).length() == 2);
+        }
+
+        {
+            span<int, 5> av = arr;
+            CHECK((av.last<0>().bounds() == static_bounds<0>()));
+            CHECK(av.last<0>().length() == 0);
+            CHECK(av.last(0).length() == 0);
+        }
+
+        {
+            span<int, 5> av = arr;
+            CHECK((av.last<5>().bounds() == static_bounds<5>()));
+            CHECK(av.last<5>().length() == 5);
+            CHECK(av.last(5).length() == 5);
+        }
+
+        {
+            span<int, 5> av = arr;
 #ifdef CONFIRM_COMPILATION_ERRORS
-		struct Foo {char c[11];};
-		auto av9 = av7.as_span<Foo>();
+            CHECK((av.last<6>().bounds() == static_bounds<6>()));
+            CHECK(av.last<6>().length() == 6);
 #endif
-	}
-
-
-	TEST (span_section_test)
-	{
-		int a[30][4][5];
-		
-		auto av = as_span(a);
-		auto sub = av.section({15, 0, 0}, gsl::index<3>{2, 2, 2});
-		auto subsub = sub.section({1, 0, 0}, gsl::index<3>{1, 1, 1});
-		(void)subsub;
-	}
-
-	TEST(span_section)
-	{
-		std::vector<int> data(5 * 10);
-		std::iota(begin(data), end(data), 0);
-		const span<int, 5, 10> av = as_span(data).as_span(dim<5>(), dim<10>());
-
-		strided_span<int, 2> av_section_1 = av.section({ 1, 2 }, { 3, 4 });
-		CHECK((av_section_1[{0, 0}] == 12));
-		CHECK((av_section_1[{0, 1}] == 13));
-		CHECK((av_section_1[{1, 0}] == 22));
-		CHECK((av_section_1[{2, 3}] == 35));
-
-		strided_span<int, 2> av_section_2 = av_section_1.section({ 1, 2 }, { 2,2 });
-		CHECK((av_section_2[{0, 0}] == 24));
-		CHECK((av_section_2[{0, 1}] == 25));
-		CHECK((av_section_2[{1, 0}] == 34));
-	}
-
-	TEST(strided_span_constructors)
-	{
-		// Check stride constructor
-		{
-			int arr[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
-			const int carr[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
-
-			strided_span<int, 1> sav1{ arr, {{9}, {1}} }; // T -> T
-			CHECK(sav1.bounds().index_bounds() == index<1>{ 9 });
-			CHECK(sav1.bounds().stride() == 1);
-			CHECK(sav1[0] == 1 && sav1[8] == 9);
-
-
-			strided_span<const int, 1> sav2{ carr, {{ 4 }, { 2 }} }; // const T -> const T
-			CHECK(sav2.bounds().index_bounds() == index<1>{ 4 });
-			CHECK(sav2.bounds().strides() == index<1>{2});
-			CHECK(sav2[0] == 1 && sav2[3] == 7);
-
-			strided_span<int, 2> sav3{ arr, {{ 2, 2 },{ 6, 2 }} }; // T -> const T
-			CHECK((sav3.bounds().index_bounds() == index<2>{ 2, 2 }));
-			CHECK((sav3.bounds().strides() == index<2>{ 6, 2 }));
-			CHECK((sav3[{0, 0}] == 1 && sav3[{0, 1}] == 3 && sav3[{1, 0}] == 7));
-		}
-
-		// Check span constructor
-		{
-			int arr[] = { 1, 2 };
-
-			// From non-cv-qualified source
-			{
-				const span<int> src = arr;
-
-				strided_span<int, 1> sav{ src, {2, 1} };
-				CHECK(sav.bounds().index_bounds() == index<1>{ 2 });
-				CHECK(sav.bounds().strides() == index<1>{ 1 });
-				CHECK(sav[1] == 2);
-
-#if _MSC_VER > 1800
-				//strided_span<const int, 1> sav_c{ {src}, {2, 1} };
-				strided_span<const int, 1> sav_c{ span<const int>{src}, strided_bounds<1>{2, 1} };
-#else
-				strided_span<const int, 1> sav_c{ span<const int>{src}, strided_bounds<1>{2, 1} };
-#endif
-				CHECK(sav_c.bounds().index_bounds() == index<1>{ 2 });
-				CHECK(sav_c.bounds().strides() == index<1>{ 1 });
-				CHECK(sav_c[1] == 2);
-
-#if _MSC_VER > 1800
-				strided_span<volatile int, 1> sav_v{ src, {2, 1} };
-#else
-				strided_span<volatile int, 1> sav_v{ span<volatile int>{src}, strided_bounds<1>{2, 1} };
-#endif
-				CHECK(sav_v.bounds().index_bounds() == index<1>{ 2 });
-				CHECK(sav_v.bounds().strides() == index<1>{ 1 });
-				CHECK(sav_v[1] == 2);
-
-#if _MSC_VER > 1800
-				strided_span<const volatile int, 1> sav_cv{ src, {2, 1} };
-#else
-				strided_span<const volatile int, 1> sav_cv{ span<const volatile int>{src}, strided_bounds<1>{2, 1} };
-#endif
-				CHECK(sav_cv.bounds().index_bounds() == index<1>{ 2 });
-				CHECK(sav_cv.bounds().strides() == index<1>{ 1 });
-				CHECK(sav_cv[1] == 2);
-			}
-
-			// From const-qualified source
-			{
-				const span<const int> src{ arr };
-
-				strided_span<const int, 1> sav_c{ src, {2, 1} };
-				CHECK(sav_c.bounds().index_bounds() == index<1>{ 2 });
-				CHECK(sav_c.bounds().strides() == index<1>{ 1 });
-				CHECK(sav_c[1] == 2);
-
-#if _MSC_VER > 1800
-				strided_span<const volatile int, 1> sav_cv{ src, {2, 1} };
-#else
-				strided_span<const volatile int, 1> sav_cv{ span<const volatile int>{src}, strided_bounds<1>{2, 1} };
-#endif
-				
-				CHECK(sav_cv.bounds().index_bounds() == index<1>{ 2 });
-				CHECK(sav_cv.bounds().strides() == index<1>{ 1 });
-				CHECK(sav_cv[1] == 2);
-			}
-
-			// From volatile-qualified source
-			{
-				const span<volatile int> src{ arr };
-
-				strided_span<volatile int, 1> sav_v{ src, {2, 1} };
-				CHECK(sav_v.bounds().index_bounds() == index<1>{ 2 });
-				CHECK(sav_v.bounds().strides() == index<1>{ 1 });
-				CHECK(sav_v[1] == 2);
-
-#if _MSC_VER > 1800
-				strided_span<const volatile int, 1> sav_cv{ src, {2, 1} };
-#else
-				strided_span<const volatile int, 1> sav_cv{ span<const volatile int>{src}, strided_bounds<1>{2, 1} };
-#endif
-				CHECK(sav_cv.bounds().index_bounds() == index<1>{ 2 });
-				CHECK(sav_cv.bounds().strides() == index<1>{ 1 });
-				CHECK(sav_cv[1] == 2);
-			}
-
-			// From cv-qualified source
-			{
-				const span<const volatile int> src{ arr };
-
-				strided_span<const volatile int, 1> sav_cv{ src, {2, 1} };
-				CHECK(sav_cv.bounds().index_bounds() == index<1>{ 2 });
-				CHECK(sav_cv.bounds().strides() == index<1>{ 1 });
-				CHECK(sav_cv[1] == 2);
-			}
-		}
-
-		// Check const-casting constructor
-		{
-			int arr[2] = { 4, 5 };
-
-			const span<int, 2> av(arr, 2);
-			span<const int, 2> av2{ av };
-			CHECK(av2[1] == 5);
-
-			static_assert(std::is_convertible<const span<int, 2>, span<const int, 2>>::value, "ctor is not implicit!");
-		
-			const strided_span<int, 1> src{ arr, {2, 1} };
-			strided_span<const int, 1> sav{ src };
-			CHECK(sav.bounds().index_bounds() == index<1>{ 2 });
-			CHECK(sav.bounds().stride() == 1);
-			CHECK(sav[1] == 5);
-			
-			static_assert(std::is_convertible<const strided_span<int, 1>, strided_span<const int, 1>>::value, "ctor is not implicit!");
-		}
-
-		// Check copy constructor
-		{
-			int arr1[2] = { 3, 4 };
-			const strided_span<int, 1> src1{ arr1, {2, 1} };
-			strided_span<int, 1> sav1{ src1 };
- 
-			CHECK(sav1.bounds().index_bounds() == index<1>{ 2 });
-			CHECK(sav1.bounds().stride() == 1);
-			CHECK(sav1[0] == 3);
-
-			int arr2[6] = { 1, 2, 3, 4, 5, 6 };
-			const strided_span<const int, 2> src2{ arr2, {{ 3, 2 }, { 2, 1 }} };
-			strided_span<const int, 2> sav2{ src2 };
-			CHECK((sav2.bounds().index_bounds() == index<2>{ 3, 2 }));
-			CHECK((sav2.bounds().strides() == index<2>{ 2, 1 }));
-			CHECK((sav2[{0, 0}] == 1 && sav2[{2, 0}] == 5));
-		}
-
-		// Check const-casting assignment operator
-		{
-			int arr1[2] = { 1, 2 };
-			int arr2[6] = { 3, 4, 5, 6, 7, 8 };
-
-			const strided_span<int, 1> src{ arr1, {{2}, {1}} };
-			strided_span<const int, 1> sav{ arr2, {{3}, {2}} };
-			strided_span<const int, 1>& sav_ref = (sav = src);
-			CHECK(sav.bounds().index_bounds() == index<1>{ 2 });
-			CHECK(sav.bounds().strides() == index<1>{ 1 });
-			CHECK(sav[0] == 1);
-			CHECK(&sav_ref == &sav);
-		}
-		
-		// Check copy assignment operator
-		{
-			int arr1[2] = { 3, 4 };
-			int arr1b[1] = { 0 };
-			const strided_span<int, 1> src1{ arr1, {2, 1} };
-			strided_span<int, 1> sav1{ arr1b, {1, 1} };
-			strided_span<int, 1>& sav1_ref = (sav1 = src1);
-			CHECK(sav1.bounds().index_bounds() == index<1>{ 2 });
-			CHECK(sav1.bounds().strides() == index<1>{ 1 });
-			CHECK(sav1[0] == 3);
-			CHECK(&sav1_ref == &sav1);
-
-			const int arr2[6] = { 1, 2, 3, 4, 5, 6 };
-			const int arr2b[1] = { 0 };
-			const strided_span<const int, 2> src2{ arr2, {{ 3, 2 },{ 2, 1 }} };
-			strided_span<const int, 2> sav2{ arr2b, {{ 1, 1 },{ 1, 1 }} };
-			strided_span<const int, 2>& sav2_ref = (sav2 = src2);
-			CHECK((sav2.bounds().index_bounds() == index<2>{ 3, 2 }));
-			CHECK((sav2.bounds().strides() == index<2>{ 2, 1 }));
-			CHECK((sav2[{0, 0}] == 1 && sav2[{2, 0}] == 5));
-			CHECK(&sav2_ref == &sav2);
-		}
-	}
-
-	TEST(strided_span_slice)
-	{
-		std::vector<int> data(5 * 10);
-		std::iota(begin(data), end(data), 0);
-		const span<int, 5, 10> src = as_span(data).as_span(dim<5>(), dim<10>());
-
-		const strided_span<int, 2> sav{ src, {{5, 10}, {10, 1}} };
-#ifdef CONFIRM_COMPILATION_ERRORS
-		const strided_span<const int, 2> csav{ {src},{ { 5, 10 },{ 10, 1 } } };
-#endif
-		const strided_span<const int, 2> csav{ span<const int, 5, 10>{ src }, { { 5, 10 },{ 10, 1 } } };
-
-		strided_span<int, 1> sav_sl = sav[2];
-		CHECK(sav_sl[0] == 20);
-		CHECK(sav_sl[9] == 29);
-
-		strided_span<const int, 1> csav_sl = sav[3];
-		CHECK(csav_sl[0] == 30);
-		CHECK(csav_sl[9] == 39);
-
-		CHECK(sav[4][0] == 40);
-		CHECK(sav[4][9] == 49);
-	}
-
-	TEST(strided_span_column_major)
-	{
-		// strided_span may be used to accomodate more peculiar
-		// use cases, such as column-major multidimensional array
-		// (aka. "FORTRAN" layout).
-
-		int cm_array[3 * 5] = {
-			1, 4, 7, 10, 13,
-			2, 5, 8, 11, 14,
-			3, 6, 9, 12, 15
-		};
-		strided_span<int, 2> cm_sav{ cm_array, {{ 5, 3 },{ 1, 5 }} };
-
-		// Accessing elements
-		CHECK((cm_sav[{0, 0}] == 1));
-		CHECK((cm_sav[{0, 1}] == 2));
-		CHECK((cm_sav[{1, 0}] == 4));
-		CHECK((cm_sav[{4, 2}] == 15));
-
-		// Slice
-		strided_span<int, 1> cm_sl = cm_sav[3];
-
-		CHECK(cm_sl[0] == 10);
-		CHECK(cm_sl[1] == 11);
-		CHECK(cm_sl[2] == 12);
-
-		// Section 
-		strided_span<int, 2> cm_sec = cm_sav.section( { 2, 1 }, { 3, 2 });
-
-		CHECK((cm_sec.bounds().index_bounds() == index<2>{3, 2}));
-		CHECK((cm_sec[{0, 0}] == 8));
-		CHECK((cm_sec[{0, 1}] == 9));
-		CHECK((cm_sec[{1, 0}] == 11));
-		CHECK((cm_sec[{2, 1}] == 15));
-	}
-
-	TEST(strided_span_bounds)
-	{
-		int arr[] = { 0, 1, 2, 3 };
-		span<int> av(arr);
-
-		{
-			// incorrect sections
-			
-			CHECK_THROW(av.section(0, 0)[0], fail_fast);
-			CHECK_THROW(av.section(1, 0)[0], fail_fast);
-			CHECK_THROW(av.section(1, 1)[1], fail_fast);
-			
-			CHECK_THROW(av.section(2, 5), fail_fast);
-			CHECK_THROW(av.section(5, 2), fail_fast);
-			CHECK_THROW(av.section(5, 0), fail_fast);
-			CHECK_THROW(av.section(0, 5), fail_fast);
-			CHECK_THROW(av.section(5, 5), fail_fast);
-		}
-
-		{
-			// zero stride
-			strided_span<int, 1> sav{ av,{ { 4 },{} } };
-			CHECK(sav[0] == 0);
-			CHECK(sav[3] == 0);
-			CHECK_THROW(sav[4], fail_fast);
-		}
-
-		{
-			// zero extent
-			strided_span<int, 1> sav{ av,{ {},{ 1 } } };
-			CHECK_THROW(sav[0], fail_fast);
-		}
-
-		{
-			// zero extent and stride
-			strided_span<int, 1> sav{ av,{ {},{} } };
-			CHECK_THROW(sav[0], fail_fast);
-		}
-
-		{
-			// strided array ctor with matching strided bounds 
-			strided_span<int, 1> sav{ arr,{ 4, 1 } };
-			CHECK(sav.bounds().index_bounds() == index<1>{ 4 });
-			CHECK(sav[3] == 3);
-			CHECK_THROW(sav[4], fail_fast);
-		}
-
-		{
-			// strided array ctor with smaller strided bounds 
-			strided_span<int, 1> sav{ arr,{ 2, 1 } };
-			CHECK(sav.bounds().index_bounds() == index<1>{ 2 });
-			CHECK(sav[1] == 1);
-			CHECK_THROW(sav[2], fail_fast);
-		}
-
-		{
-			// strided array ctor with fitting irregular bounds 
-			strided_span<int, 1> sav{ arr,{ 2, 3 } };
-			CHECK(sav.bounds().index_bounds() == index<1>{ 2 });
-			CHECK(sav[0] == 0);
-			CHECK(sav[1] == 3);
-			CHECK_THROW(sav[2], fail_fast);
-		}
-
-		{
-			// bounds cross data boundaries - from static arrays
-			CHECK_THROW((strided_span<int, 1> { arr, { 3, 2 } }), fail_fast);
-			CHECK_THROW((strided_span<int, 1> { arr, { 3, 3 } }), fail_fast);
-			CHECK_THROW((strided_span<int, 1> { arr, { 4, 5 } }), fail_fast);
-			CHECK_THROW((strided_span<int, 1> { arr, { 5, 1 } }), fail_fast);
-			CHECK_THROW((strided_span<int, 1> { arr, { 5, 5 } }), fail_fast);
-		}
-
-		{
-			// bounds cross data boundaries - from array view
-			CHECK_THROW((strided_span<int, 1> { av, { 3, 2 } }), fail_fast);
-			CHECK_THROW((strided_span<int, 1> { av, { 3, 3 } }), fail_fast);
-			CHECK_THROW((strided_span<int, 1> { av, { 4, 5 } }), fail_fast);
-			CHECK_THROW((strided_span<int, 1> { av, { 5, 1 } }), fail_fast);
-			CHECK_THROW((strided_span<int, 1> { av, { 5, 5 } }), fail_fast);
-		}
-
-		{
-			// bounds cross data boundaries - from dynamic arrays
-			CHECK_THROW((strided_span<int, 1> { av.data(), 4, { 3, 2 } }), fail_fast);
-			CHECK_THROW((strided_span<int, 1> { av.data(), 4, { 3, 3 } }), fail_fast);
-			CHECK_THROW((strided_span<int, 1> { av.data(), 4, { 4, 5 } }), fail_fast);
-			CHECK_THROW((strided_span<int, 1> { av.data(), 4, { 5, 1 } }), fail_fast);
-			CHECK_THROW((strided_span<int, 1> { av.data(), 4, { 5, 5 } }), fail_fast);
-			CHECK_THROW((strided_span<int, 1> { av.data(), 2, { 2, 2 } }), fail_fast);
-		}
-
-#ifdef CONFIRM_COMPILATION_ERRORS
-		{
-			strided_span<int, 1> sav0{ av.data(), { 3, 2 } };
-			strided_span<int, 1> sav1{ arr, { 1 } };
-			strided_span<int, 1> sav2{ arr, { 1,1,1 } };
-			strided_span<int, 1> sav3{ av, { 1 } };
-			strided_span<int, 1> sav4{ av, { 1,1,1 } };
-			strided_span<int, 2> sav5{ av.as_span(dim<2>(), dim<2>()), { 1 } };
-			strided_span<int, 2> sav6{ av.as_span(dim<2>(), dim<2>()), { 1,1,1 } };
-			strided_span<int, 2> sav7{ av.as_span(dim<2>(), dim<2>()), { { 1,1 },{ 1,1 },{ 1,1 } } };
-
-			index<1> index{ 0, 1 };
-			strided_span<int, 1> sav8{ arr,{ 1,{ 1,1 } } };
-			strided_span<int, 1> sav9{ arr,{ { 1,1 },{ 1,1 } } };
-			strided_span<int, 1> sav10{ av,{ 1,{ 1,1 } } };
-			strided_span<int, 1> sav11{ av,{ { 1,1 },{ 1,1 } } };
-			strided_span<int, 2> sav12{ av.as_span(dim<2>(), dim<2>()),{ { 1 },{ 1 } } };
-			strided_span<int, 2> sav13{ av.as_span(dim<2>(), dim<2>()),{ { 1 },{ 1,1,1 } } };
-			strided_span<int, 2> sav14{ av.as_span(dim<2>(), dim<2>()),{ { 1,1,1 },{ 1 } } };
-		}
-#endif
-	}
-
-	TEST(strided_span_type_conversion)
-	{
-		int arr[] = { 0, 1, 2, 3 };
-		span<int> av(arr);
-
-		{
-			strided_span<int, 1> sav{ av.data(), av.size(), { av.size() / 2, 2 } };
-#ifdef CONFIRM_COMPILATION_ERRORS
-			strided_span<long, 1> lsav1 = sav.as_strided_span<long, 1>();
-#endif
-		}
-		{
-			strided_span<int, 1> sav{ av, { av.size() / 2, 2 } };
-#ifdef CONFIRM_COMPILATION_ERRORS
-			strided_span<long, 1> lsav1 = sav.as_strided_span<long, 1>();
-#endif
-		}
-
-		span<const byte, dynamic_range> bytes = av.as_bytes();
-
-		// retype strided array with regular strides - from raw data
-		{
-			strided_bounds<2> bounds{ { 2, bytes.size() / 4 }, { bytes.size() / 2, 1 } };
-			strided_span<const byte, 2> sav2{ bytes.data(), bytes.size(), bounds };
-			strided_span<const int, 2> sav3 = sav2.as_strided_span<const int>();
-			CHECK(sav3[0][0] == 0);
-			CHECK(sav3[1][0] == 2);
-			CHECK_THROW(sav3[1][1], fail_fast);
-			CHECK_THROW(sav3[0][1], fail_fast);
-		}
-
-		// retype strided array with regular strides - from span
-		{
-			strided_bounds<2> bounds{ { 2, bytes.size() / 4 }, { bytes.size() / 2, 1 } };
-			span<const byte, 2, dynamic_range> bytes2 = bytes.as_span(dim<2>(), dim<>(bytes.size() / 2));
-			strided_span<const byte, 2> sav2{ bytes2, bounds };
-			strided_span<int, 2> sav3 = sav2.as_strided_span<int>();
-			CHECK(sav3[0][0] == 0);
-			CHECK(sav3[1][0] == 2);
-			CHECK_THROW(sav3[1][1], fail_fast);
-			CHECK_THROW(sav3[0][1], fail_fast);
-		}
-
-		// retype strided array with not enough elements - last dimension of the array is too small
-		{
-			strided_bounds<2> bounds{ { 4,2 },{ 4, 1 } };
-			span<const byte, 2, dynamic_range> bytes2 = bytes.as_span(dim<2>(), dim<>(bytes.size() / 2));
-			strided_span<const byte, 2> sav2{ bytes2, bounds };
-			CHECK_THROW(sav2.as_strided_span<int>(), fail_fast);
-		}
-
-		// retype strided array with not enough elements - strides are too small
-		{
-			strided_bounds<2> bounds{ { 4,2 },{ 2, 1 } };
-			span<const byte, 2, dynamic_range> bytes2 = bytes.as_span(dim<2>(), dim<>(bytes.size() / 2));
-			strided_span<const byte, 2> sav2{ bytes2, bounds };
-			CHECK_THROW(sav2.as_strided_span<int>(), fail_fast);
-		}
-
-		// retype strided array with not enough elements - last dimension does not divide by the new typesize
-		{
-			strided_bounds<2> bounds{ { 2,6 },{ 4, 1 } };
-			span<const byte, 2, dynamic_range> bytes2 = bytes.as_span(dim<2>(), dim<>(bytes.size() / 2));
-			strided_span<const byte, 2> sav2{ bytes2, bounds };
-			CHECK_THROW(sav2.as_strided_span<int>(), fail_fast);
-		}
-
-		// retype strided array with not enough elements - strides does not divide by the new typesize
-		{
-			strided_bounds<2> bounds{ { 2, 1 },{ 6, 1 } };
-			span<const byte, 2, dynamic_range> bytes2 = bytes.as_span(dim<2>(), dim<>(bytes.size() / 2));
-			strided_span<const byte, 2> sav2{ bytes2, bounds };
-			CHECK_THROW(sav2.as_strided_span<int>(), fail_fast);
-		}
-
-		// retype strided array with irregular strides - from raw data
-		{
-			strided_bounds<1> bounds{ bytes.size() / 2, 2 };
-			strided_span<const byte, 1> sav2{ bytes.data(), bytes.size(), bounds };
-			CHECK_THROW(sav2.as_strided_span<int>(), fail_fast);
-		}
-
-		// retype strided array with irregular strides - from span
-		{
-			strided_bounds<1> bounds{ bytes.size() / 2, 2 };
-			strided_span<const byte, 1> sav2{ bytes, bounds };
-			CHECK_THROW(sav2.as_strided_span<int>(), fail_fast);
-		}
-	}
-
-	TEST(empty_arrays)
-	{
-#ifdef CONFIRM_COMPILATION_ERRORS
-		{
-			span<int, 1> empty;
-			strided_span<int, 2> empty2;
-			strided_span<int, 1> empty3{ nullptr,{ 0, 1 } };
-		}
-#endif
-
-		{
-			span<int, 0> empty_av(nullptr);
-
-			CHECK(empty_av.bounds().index_bounds() == index<1>{ 0 });
-			CHECK_THROW(empty_av[0], fail_fast);
-			CHECK_THROW(empty_av.begin()[0], fail_fast);
-			CHECK_THROW(empty_av.cbegin()[0], fail_fast);		
-			for (auto& v : empty_av)
-			{
-                (void)v;
-				CHECK(false);
-			}
-		}
-
-		{
-			span<int> empty_av = {};
-			CHECK(empty_av.bounds().index_bounds() == index<1>{ 0 });
-			CHECK_THROW(empty_av[0], fail_fast);
-			CHECK_THROW(empty_av.begin()[0], fail_fast);
-			CHECK_THROW(empty_av.cbegin()[0], fail_fast); 
-			for (auto& v : empty_av)
-			{
-                (void)v;
-				CHECK(false);
-			}
-		}
-
-		{
-			span<int, 0> empty_av(nullptr);
-			strided_span<int, 1> empty_sav{ empty_av, { 0, 1 } };
-
-			CHECK(empty_sav.bounds().index_bounds() == index<1>{ 0 });
-			CHECK_THROW(empty_sav[0], fail_fast);
-			CHECK_THROW(empty_sav.begin()[0], fail_fast);
-			CHECK_THROW(empty_sav.cbegin()[0], fail_fast);
-
-			for (auto& v : empty_sav)
-			{
-                (void)v;
-				CHECK(false);
-			}
-		}
-
-		{
-			strided_span<int, 1> empty_sav{ nullptr, 0, { 0, 1 } };
-
-			CHECK(empty_sav.bounds().index_bounds() == index<1>{ 0 });
-			CHECK_THROW(empty_sav[0], fail_fast);
-			CHECK_THROW(empty_sav.begin()[0], fail_fast);
-			CHECK_THROW(empty_sav.cbegin()[0], fail_fast);
-
-			for (auto& v : empty_sav)
-			{
-                (void)v;
-				CHECK(false);
-			}
-		}
-	}
-
-	TEST(index_constructor)
-	{
-		auto arr = new int[8];
-		for (int i = 0; i < 4; ++i)
-		{
-			arr[2 * i] = 4 + i;
-			arr[2 * i + 1] = i;
-		}
-
-		span<int, dynamic_range> av(arr, 8);
-
-		ptrdiff_t a[1] = { 0 };
-		index<1> i = a;
-
-		CHECK(av[i] == 4);
-
-		auto av2 = av.as_span(dim<4>(), dim<>(2));
-        ptrdiff_t a2[2] = { 0, 1 };
-		index<2> i2 = a2;
-
-		CHECK(av2[i2] == 0);
-		CHECK(av2[0][i] == 4);
-
-		delete[] arr;
-	}
-
-	TEST(index_constructors)
-	{
-		{
-			// components of the same type
-			index<3> i1(0, 1, 2);
-			CHECK(i1[0] == 0);
-
-			// components of different types
-			size_t c0 = 0;
-			size_t c1 = 1;
-			index<3> i2(c0, c1, 2);
-			CHECK(i2[0] == 0);
-
-			// from array
-			index<3> i3 = { 0,1,2 };
-			CHECK(i3[0] == 0);
-
-			// from other index of the same size type
-			index<3> i4 = i3;
-			CHECK(i4[0] == 0);
-
-			// default
-			index<3> i7;
-			CHECK(i7[0] == 0);
-
-			// default
-			index<3> i9 = {};
-			CHECK(i9[0] == 0);
-		}
-
-		{
-			// components of the same type
-			index<1> i1(0);
-			CHECK(i1[0] == 0);
-
-			// components of different types
-			size_t c0 = 0;
-			index<1> i2(c0);
-			CHECK(i2[0] == 0);
-
-			// from array
-			index<1> i3 = { 0 };
-			CHECK(i3[0] == 0);
-
-			// from int
-			index<1> i4 = 0;
-			CHECK(i4[0] == 0);
-
-			// from other index of the same size type
-			index<1> i5 = i3;
-			CHECK(i5[0] == 0);
-
-			// default
-			index<1> i8;
-			CHECK(i8[0] == 0);
-
-			// default
-			index<1> i9 = {};
-			CHECK(i9[0] == 0);
-		}
-
-#ifdef CONFIRM_COMPILATION_ERRORS
-		{
-			index<3> i1(0, 1);
-			index<3> i2(0, 1, 2, 3);
-			index<3> i3 = { 0 };
-			index<3> i4 = { 0, 1, 2, 3 };
-			index<1> i5 = { 0,1 };
-		}
-#endif
-	}
-
-	TEST(index_operations)
-	{
-        ptrdiff_t a[3] = { 0, 1, 2 };
-        ptrdiff_t b[3] = { 3, 4, 5 };
-		index<3> i = a;
-		index<3> j = b;
-
-		CHECK(i[0] == 0);
-		CHECK(i[1] == 1);
-		CHECK(i[2] == 2);
-
-		{
-			index<3> k = i + j;
-
-			CHECK(i[0] == 0);
-			CHECK(i[1] == 1);
-			CHECK(i[2] == 2);
-			CHECK(k[0] == 3);
-			CHECK(k[1] == 5);
-			CHECK(k[2] == 7);
-		}
-
-		{
-			index<3> k = i * 3;
-
-			CHECK(i[0] == 0);
-			CHECK(i[1] == 1);
-			CHECK(i[2] == 2);
-			CHECK(k[0] == 0);
-			CHECK(k[1] == 3);
-			CHECK(k[2] == 6);
-		}
-
-		{
-			index<3> k = 3 * i;
-
-			CHECK(i[0] == 0);
-			CHECK(i[1] == 1);
-			CHECK(i[2] == 2);
-			CHECK(k[0] == 0);
-			CHECK(k[1] == 3);
-			CHECK(k[2] == 6);
-		}
-
-		{
-			index<2> k = details::shift_left(i);
-
-			CHECK(i[0] == 0);
-			CHECK(i[1] == 1);
-			CHECK(i[2] == 2);
-			CHECK(k[0] == 1);
-			CHECK(k[1] == 2);
-		}
-
-	}
-
-	void iterate_second_column(span<int, dynamic_range, dynamic_range> av)
-	{
-		auto length = av.size() / 2;
-
-		// view to the second column 
-		auto section = av.section({ 0,1 }, { length,1 });
-
-		CHECK(section.size() == length);
-		for (auto i = 0; i < section.size(); ++i)
-		{
-			CHECK(section[i][0] == av[i][1]);
-		}
-
-		for (auto i = 0; i < section.size(); ++i)
-		{
-			auto idx = index<2>{ i,0 }; // avoid braces inside the CHECK macro
-			CHECK(section[idx] == av[i][1]);
-		}
-
-		CHECK(section.bounds().index_bounds()[0] == length);
-		CHECK(section.bounds().index_bounds()[1] == 1);
-		for (auto i = 0; i < section.bounds().index_bounds()[0]; ++i)
-		{
-			for (auto j = 0; j < section.bounds().index_bounds()[1]; ++j)
-			{
-				auto idx = index<2>{ i,j }; // avoid braces inside the CHECK macro
-				CHECK(section[idx] == av[i][1]);
-			}
-		}
-
-		size_t check_sum = 0;
-		for (auto i = 0; i < length; ++i)
-		{
-			check_sum += av[i][1];
-		}
-
-		{
-			auto idx = 0;
-			size_t sum = 0;
-			for (auto num : section)
-			{
-				CHECK(num == av[idx][1]);
-				sum += num;
-				idx++;
-			}
-
-			CHECK(sum == check_sum);
-		}
-		{
-			size_t idx = length - 1;
-			size_t sum = 0;
-			for (auto iter = section.rbegin(); iter != section.rend(); ++iter)
-			{
-				CHECK(*iter == av[idx][1]);
-				sum += *iter;
-				idx--;
-			}
-
-			CHECK(sum == check_sum);
-		}
-	}
-
-	TEST(span_section_iteration)
-	{
-		int arr[4][2] = { { 4,0 },{ 5,1 },{ 6,2 },{ 7,3 } };
-
-		// static bounds
-		{
-			span<int, 4, 2> av = arr;
-			iterate_second_column(av);
-		}
-		// first bound is dynamic
-		{
-			span<int, dynamic_range, 2> av  = arr;
-			iterate_second_column(av);
-		}
-		// second bound is dynamic
-		{
-			span<int, 4, dynamic_range> av = arr;
-			iterate_second_column(av);
-		}
-		// both bounds are dynamic
-		{
-			span<int, dynamic_range, dynamic_range> av = arr;
-			iterate_second_column(av);
-		}
-	}
-
-	TEST(dynamic_span_section_iteration)
-	{
-		auto height = 4, width = 2;
-		auto size = height * width;
-
-		auto arr = new int[size];
-		for (auto i = 0; i < size; ++i)
-		{
-			arr[i] = i;
-		}
-
-		auto av = as_span(arr, size);
-
-		// first bound is dynamic
-		{
-			span<int, dynamic_range, 2> av2 = av.as_span(dim<>(height), dim<>(width));
-			iterate_second_column(av2);
-		}
-		// second bound is dynamic
-		{
-			span<int, 4, dynamic_range> av2 = av.as_span(dim<>(height), dim<>(width));
-			iterate_second_column(av2);
-		}
-		// both bounds are dynamic
-		{
-			span<int, dynamic_range, dynamic_range> av2 = av.as_span(dim<>(height), dim<>(width));
-			iterate_second_column(av2);
-		}
-
-		delete[] arr;
-	}
-
-	void iterate_every_other_element(span<int, dynamic_range> av)
-	{
-		// pick every other element
-
-		auto length = av.size() / 2;
-#if _MSC_VER > 1800
-		auto bounds = strided_bounds<1>({ length }, { 2 });
-#else
-		auto bounds = strided_bounds<1>(index<1>{ length }, index<1>{ 2 });
-#endif
-		strided_span<int, 1> strided(&av.data()[1], av.size() - 1, bounds);
-
-		CHECK(strided.size() == length);
-		CHECK(strided.bounds().index_bounds()[0] == length);
-		for (auto i = 0; i < strided.size(); ++i)
-		{
-			CHECK(strided[i] == av[2 * i + 1]);
-		}
-
-		int idx = 0;
-		for (auto num : strided)
-		{
-			CHECK(num == av[2 * idx + 1]);
-			idx++;
-		}
-	}
-
-	TEST(strided_span_section_iteration)
-	{
-		int arr[8] = {4,0,5,1,6,2,7,3};
-
-		// static bounds
-		{
-			span<int, 8> av(arr, 8);
-			iterate_every_other_element(av);
-		}
-
-		// dynamic bounds
-		{
-			span<int, dynamic_range> av(arr, 8);
-			iterate_every_other_element(av);
-		}
-	}
-
-	TEST(dynamic_strided_span_section_iteration)
-	{
-		auto arr = new int[8];
-		for (int i = 0; i < 4; ++i)
-		{
-			arr[2 * i] = 4 + i;
-			arr[2 * i + 1] = i;
-		}
-		
-		auto av = as_span(arr, 8);
-		iterate_every_other_element(av);
-
-		delete[] arr;
-	}
-
-	void iterate_second_slice(span<int, dynamic_range, dynamic_range, dynamic_range> av)
-	{
-		int expected[6] = { 2,3,10,11,18,19 };
-		auto section = av.section({ 0,1,0 }, { 3,1,2 });
-
-		for (auto i = 0; i < section.extent<0>(); ++i)
-		{
-			for (auto j = 0; j < section.extent<1>(); ++j)
-				for (auto k = 0; k < section.extent<2>(); ++k)
-				{
-					auto idx = index<3>{ i,j,k }; // avoid braces in the CHECK macro
-					CHECK(section[idx] == expected[2 * i + 2 * j + k]);
-				}
-		}
-
-		for (auto i = 0; i < section.extent<0>(); ++i)
-		{
-			for (auto j = 0; j < section.extent<1>(); ++j)
-				for (auto k = 0; k < section.extent<2>(); ++k)
-					CHECK(section[i][j][k] == expected[2 * i + 2 * j + k]);
-		}
-
-		int i = 0;
-		for (auto num : section)
-		{
-			CHECK(num == expected[i]);
-			i++;
-		}
-	}
-
-	TEST(strided_span_section_iteration_3d)
-	{
-		int arr[3][4][2];
-		for (auto i = 0; i < 3; ++i)
-		{
-			for (auto j = 0; j < 4; ++j)
-				for (auto k = 0; k < 2; ++k)
-					arr[i][j][k] = 8 * i + 2 * j + k;
-		}
-
-		{
-			span<int, 3, 4, 2> av = arr;
-			iterate_second_slice(av);
-		}
-	}
-
-	TEST(dynamic_strided_span_section_iteration_3d)
-	{
-		auto height = 12, width = 2;
-		auto size = height * width;
-
-		auto arr = new int[size];
-		for (auto i = 0; i < size; ++i)
-		{
-			arr[i] = i;
-		}
-
-		{
-			auto av = as_span(arr, 24).as_span(dim<3>(),dim<4>(),dim<2>());
-			iterate_second_slice(av);
-		}
-
-		{
-			auto av = as_span(arr, 24).as_span(dim<>(3), dim<4>(), dim<2>());
-			iterate_second_slice(av);
-		}
-
-		{
-			auto av = as_span(arr, 24).as_span(dim<3>(), dim<>(4), dim<2>());
-			iterate_second_slice(av);
-		}
-
-		{
-			auto av = as_span(arr, 24).as_span(dim<3>(), dim<4>(), dim<>(2));
-			iterate_second_slice(av);
-		}
-		delete[] arr;
-	}
-
-	TEST(strided_span_conversion)
-	{
-		// get an span of 'c' values from the list of X's
-
-		struct X { int a; int b; int c; };
-
-		X arr[4] = { { 0,1,2 },{ 3,4,5 },{ 6,7,8 },{ 9,10,11 } };
-
-		int s = sizeof(int) / sizeof(byte);
-		auto d2 = 3 * s;
-		auto d1 = sizeof(int) * 12 / d2;
-
-		// convert to 4x12 array of bytes
-		auto av = as_span(arr, 4).as_bytes().as_span(dim<>(d1), dim<>(d2));
-
-		CHECK(av.bounds().index_bounds()[0] == 4);
-		CHECK(av.bounds().index_bounds()[1] == 12);
-
-		// get the last 4 columns
-		auto section = av.section({ 0, 2 * s }, { 4, s }); // { { arr[0].c[0], arr[0].c[1], arr[0].c[2], arr[0].c[3] } , { arr[1].c[0], ... } , ... }
-
-		// convert to array 4x1 array of integers
-		auto cs = section.as_strided_span<int>(); // { { arr[0].c }, {arr[1].c } , ... } 
-
-		CHECK(cs.bounds().index_bounds()[0] == 4);
-		CHECK(cs.bounds().index_bounds()[1] == 1);
-
-		// transpose to 1x4 array 
-		strided_bounds<2> reverse_bounds{ 
-			{ cs.bounds().index_bounds()[1] , cs.bounds().index_bounds()[0] },
-			{ cs.bounds().strides()[1], cs.bounds().strides()[0] }
-		};
-
-		strided_span<int, 2> transposed{ cs.data(), cs.bounds().total_size(), reverse_bounds };
-		
-		// slice to get a one-dimensional array of c's
-		strided_span<int, 1> result = transposed[0];
-
-		CHECK(result.bounds().index_bounds()[0] == 4);
-		CHECK_THROW(result.bounds().index_bounds()[1], fail_fast);
-
-		int i = 0;
-		for (auto& num : result)
-		{
-			CHECK(num == arr[i].c);
-			i++;
-		}
-
-	}
-
-	TEST(constructors)
-	{
-		span<int, dynamic_range> av(nullptr);
-		CHECK(av.length() == 0);
-
-		span<int, dynamic_range> av2;
-		CHECK(av2.length() == 0);
-
-		span<int, dynamic_range> av3(nullptr, 0);
-		CHECK(av3.length() == 0);
-
-		// Constructing from a nullptr + length is specifically disallowed
-		auto f = [&]() {span<int, dynamic_range> av4(nullptr, 2);};
-		CHECK_THROW(f(), fail_fast);
-
-		int arr1[2][3];
-		span<int, 2, dynamic_range> av5(arr1);
-
-		array<int, 15> arr2;
-		span<int, 15> av6(arr2);
-
-		vector<int> vec1(19);
-		span<int> av7(vec1);
-		CHECK(av7.length() == 19);
-
-
-		span<int> av8;
-		CHECK(av8.length() == 0);
-		span<int> av9(arr2);
-		CHECK(av9.length() == 15);
-
-
-#ifdef CONFIRM_COMPILATION_ERRORS
-		span<int, 4> av10;
-		DerivedClass *p = nullptr;
-		span<BaseClass> av11(p, 0);
-#endif
-	}
-
-	TEST(copyandassignment)
-	{
-		span<int, dynamic_range> av1;
-
-		int arr[] = {3, 4, 5};
-		av1 = arr;
-		span<const int, dynamic_range> av2;
-		av2 = av1;
-	}
-
-	TEST(span_first)
-	{
-		int arr[5] = { 1, 2, 3, 4, 5 };
-
-		{
-			span<int, 5> av = arr;
-			CHECK((av.first<2>().bounds() == static_bounds<2>()));
-			CHECK(av.first<2>().length() == 2);
-			CHECK(av.first(2).length() == 2);
-		}
-
-		{
-			span<int, 5> av = arr;
-			CHECK((av.first<0>().bounds() == static_bounds<0>()));
-			CHECK(av.first<0>().length() == 0);
-			CHECK(av.first(0).length() == 0);
-		}
-
-		{
-			span<int, 5> av = arr;
-			CHECK((av.first<5>().bounds() == static_bounds<5>()));
-			CHECK(av.first<5>().length() == 5);
-			CHECK(av.first(5).length() == 5);
-		}
-
-		{
-			span<int, 5> av = arr;
-#ifdef CONFIRM_COMPILATION_ERRORS
-			CHECK(av.first<6>().bounds() == static_bounds<6>());
-			CHECK(av.first<6>().length() == 6);
-#endif
-			CHECK_THROW(av.first(6).length(), fail_fast);
-		}
-
-		{
-			span<int, dynamic_range> av;
-			CHECK((av.first<0>().bounds() == static_bounds<0>()));
-			CHECK(av.first<0>().length() == 0);
-			CHECK(av.first(0).length() == 0);
-		}
-	}
-
-	TEST(span_last)
-	{
-		int arr[5] = { 1, 2, 3, 4, 5 };
-
-		{
-			span<int, 5> av = arr;
-			CHECK((av.last<2>().bounds() == static_bounds<2>()));
-			CHECK(av.last<2>().length() == 2);
-			CHECK(av.last(2).length() == 2);
-		}
-
-		{
-			span<int, 5> av = arr;
-			CHECK((av.last<0>().bounds() == static_bounds<0>()));
-			CHECK(av.last<0>().length() == 0);
-			CHECK(av.last(0).length() == 0);
-		}
-
-		{
-			span<int, 5> av = arr;
-			CHECK((av.last<5>().bounds() == static_bounds<5>()));
-			CHECK(av.last<5>().length() == 5);
-			CHECK(av.last(5).length() == 5);
-		}
-
-		
-		{
-			span<int, 5> av = arr;
-#ifdef CONFIRM_COMPILATION_ERRORS
-			CHECK((av.last<6>().bounds() == static_bounds<6>()));
-			CHECK(av.last<6>().length() == 6);
-#endif
-			CHECK_THROW(av.last(6).length(), fail_fast);
-		}
-
-		{
-			span<int, dynamic_range> av;
-			CHECK((av.last<0>().bounds() == static_bounds<0>()));
-			CHECK(av.last<0>().length() == 0);
-			CHECK(av.last(0).length() == 0);
-		}
-	}
-
-	TEST(customized_span_size)
-	{
-		double (*arr)[3][4] = new double[100][3][4];
-		span<double, dynamic_range, 3, 4> av1(arr, 10);
-
-		struct EffectiveStructure
-		{
-			double* v1;
-			ptrdiff_t v2;
-		};
-		CHECK(sizeof(av1) == sizeof(EffectiveStructure));
-
-		CHECK_THROW(av1[10][3][4], fail_fast);
-
-		span<const double, dynamic_range, 6, 4> av2 = av1.as_span(dim<>(5), dim<6>(), dim<4>());
-		(void)av2;
-	}
-
-	TEST(span_sub)
-	{
-		int arr[5] = { 1, 2, 3, 4, 5 };
-
-		{
-			span<int, 5> av = arr;
-			CHECK((av.sub<2,2>().bounds() == static_bounds<2>()));
-			CHECK((av.sub<2,2>().length() == 2));
-			CHECK(av.sub(2,2).length() == 2);
-            		CHECK(av.sub(2,3).length() == 3);
-		}
-
-
-		{
-			span<int, 5> av = arr;
-			CHECK((av.sub<0,0>().bounds() == static_bounds<0>()));
-			CHECK((av.sub<0,0>().length() == 0));
-			CHECK(av.sub(0,0).length() == 0);
-		}
-
-		{
-			span<int, 5> av = arr;
-			CHECK((av.sub<0,5>().bounds() == static_bounds<5>()));
-			CHECK((av.sub<0,5>().length() == 5));
-			CHECK(av.sub(0,5).length() == 5);
-		        CHECK_THROW(av.sub(0,6).length(), fail_fast);
-		        CHECK_THROW(av.sub(1,5).length(), fail_fast);
-		}
-
-		{
-			span<int, 5> av = arr;
-			CHECK((av.sub<5,0>().bounds() == static_bounds<0>()));
-            		CHECK((av.sub<5, 0>().length() == 0));
-            		CHECK(av.sub(5,0).length() == 0);
-            		CHECK_THROW(av.sub(6,0).length(), fail_fast);
-		}
-
-		{
-			span<int, dynamic_range> av;
-			CHECK((av.sub<0,0>().bounds() == static_bounds<0>()));
-			CHECK((av.sub<0,0>().length() == 0));
-			CHECK(av.sub(0,0).length() == 0);
-            		CHECK_THROW((av.sub<1,0>().length()), fail_fast);
-		}
+            CHECK_THROW(av.last(6).length(), fail_fast);
+        }
+
+        {
+            span<int, dynamic_range> av;
+            CHECK((av.last<0>().bounds() == static_bounds<0>()));
+            CHECK(av.last<0>().length() == 0);
+            CHECK(av.last(0).length() == 0);
+        }
+    }
+
+    TEST(subspan)
+    {
+        int arr[5] = {1, 2, 3, 4, 5};
+
+        {
+            span<int, 5> av = arr;
+            CHECK((av.subspan<2, 2>().bounds() == static_bounds<2>()));
+            CHECK((av.subspan<2, 2>().length() == 2));
+            CHECK(av.subspan(2, 2).length() == 2);
+            CHECK(av.subspan(2, 3).length() == 3);
+        }
+
+        {
+            span<int, 5> av = arr;
+            CHECK((av.subspan<0, 0>().bounds() == static_bounds<0>()));
+            CHECK((av.subspan<0, 0>().length() == 0));
+            CHECK(av.subspan(0, 0).length() == 0);
+        }
+
+        {
+            span<int, 5> av = arr;
+            CHECK((av.subspan<0, 5>().bounds() == static_bounds<5>()));
+            CHECK((av.subspan<0, 5>().length() == 5));
+            CHECK(av.subspan(0, 5).length() == 5);
+            CHECK_THROW(av.subspan(0, 6).length(), fail_fast);
+            CHECK_THROW(av.subspan(1, 5).length(), fail_fast);
+        }
+
+        {
+            span<int, 5> av = arr;
+            CHECK((av.subspan<5, 0>().bounds() == static_bounds<0>()));
+            CHECK((av.subspan<5, 0>().length() == 0));
+            CHECK(av.subspan(5, 0).length() == 0);
+            CHECK_THROW(av.subspan(6, 0).length(), fail_fast);
+        }
+
+        {
+            span<int, dynamic_range> av;
+            CHECK((av.subspan<0, 0>().bounds() == static_bounds<0>()));
+            CHECK((av.subspan<0, 0>().length() == 0));
+            CHECK(av.subspan(0, 0).length() == 0);
+            CHECK_THROW((av.subspan<1, 0>().length()), fail_fast);
+        }
 
         {
             span<int> av;
-            CHECK(av.sub(0).length() == 0);
-            CHECK_THROW(av.sub(1).length(), fail_fast);
+            CHECK(av.subspan(0).length() == 0);
+            CHECK_THROW(av.subspan(1).length(), fail_fast);
         }
 
         {
             span<int> av = arr;
-            CHECK(av.sub(0).length() == 5);
-            CHECK(av.sub(1).length() == 4);
-            CHECK(av.sub(4).length() == 1);
-            CHECK(av.sub(5).length() == 0);
-            CHECK_THROW(av.sub(6).length(), fail_fast);
-            auto av2 = av.sub(1);
-            for (int i = 0; i < 4; ++i)
-                CHECK(av2[i] == i+2);
+            CHECK(av.subspan(0).length() == 5);
+            CHECK(av.subspan(1).length() == 4);
+            CHECK(av.subspan(4).length() == 1);
+            CHECK(av.subspan(5).length() == 0);
+            CHECK_THROW(av.subspan(6).length(), fail_fast);
+            auto av2 = av.subspan(1);
+            for (int i = 0; i < 4; ++i) CHECK(av2[i] == i + 2);
         }
-        
+
         {
-            span<int,5> av = arr;
-            CHECK(av.sub(0).length() == 5);
-            CHECK(av.sub(1).length() == 4);
-            CHECK(av.sub(4).length() == 1);
-            CHECK(av.sub(5).length() == 0);
-            CHECK_THROW(av.sub(6).length(), fail_fast);
-            auto av2 = av.sub(1);
-            for (int i = 0; i < 4; ++i)
-                CHECK(av2[i] == i+2);
+            span<int, 5> av = arr;
+            CHECK(av.subspan(0).length() == 5);
+            CHECK(av.subspan(1).length() == 4);
+            CHECK(av.subspan(4).length() == 1);
+            CHECK(av.subspan(5).length() == 0);
+            CHECK_THROW(av.subspan(6).length(), fail_fast);
+            auto av2 = av.subspan(1);
+            for (int i = 0; i < 4; ++i) CHECK(av2[i] == i + 2);
         }
     }
 
-	void AssertNullEmptyProperties(span<int, dynamic_range>& av)
-	{
-		CHECK(av.length() == 0);
-		CHECK(av.data() == nullptr);
-		CHECK(!av);
-	}
+    TEST(rank)
+    {
+        int arr[2] = {1, 2};
 
-	template <class T, class U>
-	void AssertContentsMatch(T a1, U a2)
-	{
-		CHECK(a1.length() == a2.length());
-		for (auto i = 0; i < a1.length(); ++i)
-			CHECK(a1[i] == a2[i]);
-	}
+        {
+            span<int> s;
+            CHECK(s.rank() == 1);
+        }
 
-	TEST(TestNullConstruction)
-	{
-		span<int, dynamic_range> av;
-		AssertNullEmptyProperties(av);
+        {
+            span<int, 2> s = arr;
+            CHECK(s.rank() == 1);
+        }
 
-		span<int, dynamic_range> av2(nullptr);
-		AssertNullEmptyProperties(av2);
-	}
+        int arr2d[1][1] = {};
+        {
+            span<int, 1, 1> s = arr2d;
+            CHECK(s.rank() == 2);
+        }
+    }
 
-	TEST(ArrayConstruction)
-	{
-		int a[] = { 1, 2, 3, 4 };
+    TEST(extent)
+    {
+        {
+            span<int> s;
+            CHECK(s.extent() == 0);
+            CHECK(s.extent(0) == 0);
+            CHECK_THROW(s.extent(1), fail_fast);
+#ifdef CONFIRM_COMPILATION_ERRORS
+            CHECK(s.extent<1>() == 0);
+#endif
+        }
 
-		span<int, dynamic_range> av = { &a[1], 3 };
-		CHECK(av.length() == 3);
+        {
+            span<int, 0> s;
+            CHECK(s.extent() == 0);
+            CHECK(s.extent(0) == 0);
+            CHECK_THROW(s.extent(1), fail_fast);
+        }
 
-		span<int, dynamic_range> av3 = { a, 2 };
-		CHECK(av3.length() == 2);
+        {
+            int arr2d[1][2] = {};
 
-		span<int, dynamic_range> av2 = a;
-		CHECK(av2.length() == 4);
-	}
+            span<int, 1, 2> s = arr2d;
+            CHECK(s.extent() == 1);
+            CHECK(s.extent<0>() == 1);
+            CHECK(s.extent<1>() == 2);
+            CHECK(s.extent(0) == 1);
+            CHECK(s.extent(1) == 2);
+            CHECK_THROW(s.extent(3), fail_fast);
+        }
 
-	TEST(NonConstConstConversions)
-	{
-		int a[] = { 1, 2, 3, 4 };
+        {
+            int arr2d[1][2] = {};
+
+            span<int, 0, 2> s = arr2d;
+            CHECK(s.extent() == 0);
+            CHECK(s.extent<0>() == 0);
+            CHECK(s.extent<1>() == 2);
+            CHECK(s.extent(0) == 0);
+            CHECK(s.extent(1) == 2);
+            CHECK_THROW(s.extent(3), fail_fast);
+        }
+    }
+
+    TEST(operator_function_call)
+    {
+        int arr[4] = {1, 2, 3, 4};
+
+        {
+            span<int> s = arr;
+            CHECK(s(0) == 1);
+            CHECK_THROW(s(5), fail_fast);
+        }
+
+        int arr2d[2][3] = {1, 2, 3, 4, 5, 6};
+
+        {
+            span<int, 2, 3> s = arr2d;
+            CHECK(s(0, 0) == 1);
+            CHECK(s(1, 2) == 6);
+        }
+    }
+
+    TEST(comparison_operators)
+    {
+        {
+            int arr[10][2];
+            auto s1 = as_span(arr);
+            span<const int, dynamic_range, 2> s2 = s1;
+
+            CHECK(s1 == s2);
+
+            span<int, 20> s3 = as_span(s1, dim<>(20));
+            CHECK(s3 == s2 && s3 == s1);
+        }
+
+        {
+            auto s1 = nullptr;
+            auto s2 = nullptr;
+            CHECK(s1 == s2);
+            CHECK(!(s1 != s2));
+            CHECK(!(s1 < s2));
+            CHECK(s1 <= s2);
+            CHECK(!(s1 > s2));
+            CHECK(s1 >= s2);
+            CHECK(s2 == s1);
+            CHECK(!(s2 != s1));
+            CHECK(!(s2 < s1));
+            CHECK(s2 <= s1);
+            CHECK(!(s2 > s1));
+            CHECK(s2 >= s1);
+        }
+
+        {
+            int arr[] = {2, 1}; // bigger
+
+            span<int> s1 = nullptr;
+            span<int> s2 = arr;
+
+            CHECK(s1 != s2);
+            CHECK(s2 != s1);
+            CHECK(!(s1 == s2));
+            CHECK(!(s2 == s1));
+            CHECK(s1 < s2);
+            CHECK(!(s2 < s1));
+            CHECK(s1 <= s2);
+            CHECK(!(s2 <= s1));
+            CHECK(s2 > s1);
+            CHECK(!(s1 > s2));
+            CHECK(s2 >= s1);
+            CHECK(!(s1 >= s2));
+        }
+
+        {
+            int arr1[] = {1, 2};
+            int arr2[] = {1, 2};
+            span<int> s1 = arr1;
+            span<int> s2 = arr2;
+
+            CHECK(s1 == s2);
+            CHECK(!(s1 != s2));
+            CHECK(!(s1 < s2));
+            CHECK(s1 <= s2);
+            CHECK(!(s1 > s2));
+            CHECK(s1 >= s2);
+            CHECK(s2 == s1);
+            CHECK(!(s2 != s1));
+            CHECK(!(s2 < s1));
+            CHECK(s2 <= s1);
+            CHECK(!(s2 > s1));
+            CHECK(s2 >= s1);
+        }
+
+        {
+            int arr[] = {1, 2, 3};
+
+            span<int> s1 = {&arr[0], 2}; // shorter
+            span<int> s2 = arr; // longer
+
+            CHECK(s1 != s2);
+            CHECK(s2 != s1);
+            CHECK(!(s1 == s2));
+            CHECK(!(s2 == s1));
+            CHECK(s1 < s2);
+            CHECK(!(s2 < s1));
+            CHECK(s1 <= s2);
+            CHECK(!(s2 <= s1));
+            CHECK(s2 > s1);
+            CHECK(!(s1 > s2));
+            CHECK(s2 >= s1);
+            CHECK(!(s1 >= s2));
+        }
+
+        {
+            int arr1[] = {1, 2}; // smaller
+            int arr2[] = {2, 1}; // bigger
+
+            span<int> s1 = arr1;
+            span<int> s2 = arr2;
+
+            CHECK(s1 != s2);
+            CHECK(s2 != s1);
+            CHECK(!(s1 == s2));
+            CHECK(!(s2 == s1));
+            CHECK(s1 < s2);
+            CHECK(!(s2 < s1));
+            CHECK(s1 <= s2);
+            CHECK(!(s2 <= s1));
+            CHECK(s2 > s1);
+            CHECK(!(s1 > s2));
+            CHECK(s2 >= s1);
+            CHECK(!(s1 >= s2));
+        }
+    }
+
+    TEST(basics)
+    {
+        auto ptr = as_span(new int[10], 10);
+        fill(ptr.begin(), ptr.end(), 99);
+        for (int num : ptr) {
+            CHECK(num == 99);
+        }
+
+        delete[] ptr.data();
+    }
+
+    TEST(bounds_checks)
+    {
+        int arr[10][2];
+        auto av = as_span(arr);
+
+        fill(begin(av), end(av), 0);
+
+        av[2][0] = 1;
+        av[1][1] = 3;
+
+        // out of bounds
+        CHECK_THROW(av[1][3] = 3, fail_fast);
+        CHECK_THROW((av[{1, 3}] = 3), fail_fast);
+
+        CHECK_THROW(av[10][2], fail_fast);
+        CHECK_THROW((av[{10, 2}]), fail_fast);
+    }
+
+    void overloaded_func(span<const int, dynamic_range, 3, 5> exp, int expected_value)
+    {
+        for (auto val : exp) {
+            CHECK(val == expected_value);
+        }
+    }
+
+    void overloaded_func(span<const char, dynamic_range, 3, 5> exp, char expected_value)
+    {
+        for (auto val : exp) {
+            CHECK(val == expected_value);
+        }
+    }
+
+    void fixed_func(span<int, 3, 3, 5> exp, int expected_value)
+    {
+        for (auto val : exp) {
+            CHECK(val == expected_value);
+        }
+    }
+
+    TEST(span_parameter_test)
+    {
+        auto data = new int[4][3][5];
+
+        auto av = as_span(data, 4);
+
+        CHECK(av.size() == 60);
+
+        fill(av.begin(), av.end(), 34);
+
+        int count = 0;
+        for_each(av.rbegin(), av.rend(), [&](int val) { count += val; });
+        CHECK(count == 34 * 60);
+        overloaded_func(av, 34);
+
+        overloaded_func(as_span(av, dim<>(4), dim<>(3), dim<>(5)), 34);
+
+        // fixed_func(av, 34);
+        delete[] data;
+    }
+
+    TEST(md_access)
+    {
+        auto width = 5, height = 20;
+
+        auto imgSize = width * height;
+        auto image_ptr = new int[imgSize][3];
+
+        // size check will be done
+        auto image_view =
+            as_span(as_span(image_ptr, imgSize), dim<>(height), dim<>(width), dim<3>());
+
+        iota(image_view.begin(), image_view.end(), 1);
+
+        int expected = 0;
+        for (auto i = 0; i < height; i++) {
+            for (auto j = 0; j < width; j++) {
+                CHECK(expected + 1 == image_view[i][j][0]);
+                CHECK(expected + 2 == image_view[i][j][1]);
+                CHECK(expected + 3 == image_view[i][j][2]);
+
+                auto val = image_view[{i, j, 0}];
+                CHECK(expected + 1 == val);
+                val = image_view[{i, j, 1}];
+                CHECK(expected + 2 == val);
+                val = image_view[{i, j, 2}];
+                CHECK(expected + 3 == val);
+
+                expected += 3;
+            }
+        }
+    }
+
+    TEST(as_span)
+    {
+        {
+            int* arr = new int[150];
+
+            auto av = as_span(arr, dim<10>(), dim<>(3), dim<5>());
+
+            fill(av.begin(), av.end(), 24);
+            overloaded_func(av, 24);
+
+            delete[] arr;
+
+            array<int, 15> stdarr{0};
+            auto av2 = as_span(stdarr);
+            overloaded_func(as_span(av2, dim<>(1), dim<3>(), dim<5>()), 0);
+
+            string str = "ttttttttttttttt"; // size = 15
+            auto t = str.data();
+            (void) t;
+            auto av3 = as_span(str);
+            overloaded_func(as_span(av3, dim<>(1), dim<3>(), dim<5>()), 't');
+        }
+
+        {
+            string str;
+            span<char> strspan = as_span(str);
+            (void) strspan;
+            const string cstr;
+            span<const char> cstrspan = as_span(cstr);
+            (void) cstrspan;
+        }
+
+        {
+            int a[3][4][5];
+            auto av = as_span(a);
+            const int(*b)[4][5];
+            b = a;
+            auto bv = as_span(b, 3);
+
+            CHECK(av == bv);
+
+            const std::array<double, 3> arr = {0.0, 0.0, 0.0};
+            auto cv = as_span(arr);
+            (void) cv;
+
+            vector<float> vec(3);
+            auto dv = as_span(vec);
+            (void) dv;
 
 #ifdef CONFIRM_COMPILATION_ERRORS
-		span<const int, dynamic_range> cav = a;
-		span<int, dynamic_range> av = cav;
-#else
-		span<int, dynamic_range> av = a;
-		span<const int, dynamic_range> cav = av;			 
+            auto dv2 = as_span(std::move(vec));
 #endif
-		AssertContentsMatch(av, cav);
-	}
+        }
+    }
 
-	TEST(FixedSizeConversions)
-	{			
-		int arr[] = { 1, 2, 3, 4 };
-	
-		// converting to an span from an equal size array is ok
-		span<int, 4> av4 = arr;
-		CHECK(av4.length() == 4);
+    TEST(empty_spans)
+    {
+        {
+            span<int, 0> empty_av(nullptr);
 
-		// converting to dynamic_range a_v is always ok
-		{
-			span<int, dynamic_range> av = av4;
-			(void)av;
-		}
-		{
-			span<int, dynamic_range> av = arr;
-			(void)av;
-		}
+            CHECK(empty_av.bounds().index_bounds() == index<1>{0});
+            CHECK_THROW(empty_av[0], fail_fast);
+            CHECK_THROW(empty_av.begin()[0], fail_fast);
+            CHECK_THROW(empty_av.cbegin()[0], fail_fast);
+            for (auto& v : empty_av) {
+                (void) v;
+                CHECK(false);
+            }
+        }
 
-		// initialization or assignment to static span that REDUCES size is NOT ok
-#ifdef CONFIRM_COMPILATION_ERRORS
-		{
-			span<int, 2> av2 = arr;
-		}
-		{
-			span<int, 2> av2 = av4;
-		}
-#endif
+        {
+            span<int> empty_av = {};
+            CHECK(empty_av.bounds().index_bounds() == index<1>{0});
+            CHECK_THROW(empty_av[0], fail_fast);
+            CHECK_THROW(empty_av.begin()[0], fail_fast);
+            CHECK_THROW(empty_av.cbegin()[0], fail_fast);
+            for (auto& v : empty_av) {
+                (void) v;
+                CHECK(false);
+            }
+        }
+    }
 
-		{
-			span<int, dynamic_range> av = arr;
-			span<int, 2> av2 = av;
-			(void)av2;
-		}
+    TEST(index_constructor)
+    {
+        auto arr = new int[8];
+        for (int i = 0; i < 4; ++i) {
+            arr[2 * i] = 4 + i;
+            arr[2 * i + 1] = i;
+        }
+
+        span<int, dynamic_range> av(arr, 8);
+
+        ptrdiff_t a[1] = {0};
+        index<1> i = a;
+
+        CHECK(av[i] == 4);
+
+        auto av2 = as_span(av, dim<4>(), dim<>(2));
+        ptrdiff_t a2[2] = {0, 1};
+        index<2> i2 = a2;
+
+        CHECK(av2[i2] == 0);
+        CHECK(av2[0][i] == 4);
+
+        delete[] arr;
+    }
+
+    TEST(index_constructors)
+    {
+        {
+            // components of the same type
+            index<3> i1(0, 1, 2);
+            CHECK(i1[0] == 0);
+
+            // components of different types
+            size_t c0 = 0;
+            size_t c1 = 1;
+            index<3> i2(c0, c1, 2);
+            CHECK(i2[0] == 0);
+
+            // from array
+            index<3> i3 = {0, 1, 2};
+            CHECK(i3[0] == 0);
+
+            // from other index of the same size type
+            index<3> i4 = i3;
+            CHECK(i4[0] == 0);
+
+            // default
+            index<3> i7;
+            CHECK(i7[0] == 0);
+
+            // default
+            index<3> i9 = {};
+            CHECK(i9[0] == 0);
+        }
+
+        {
+            // components of the same type
+            index<1> i1(0);
+            CHECK(i1[0] == 0);
+
+            // components of different types
+            size_t c0 = 0;
+            index<1> i2(c0);
+            CHECK(i2[0] == 0);
+
+            // from array
+            index<1> i3 = {0};
+            CHECK(i3[0] == 0);
+
+            // from int
+            index<1> i4 = 0;
+            CHECK(i4[0] == 0);
+
+            // from other index of the same size type
+            index<1> i5 = i3;
+            CHECK(i5[0] == 0);
+
+            // default
+            index<1> i8;
+            CHECK(i8[0] == 0);
+
+            // default
+            index<1> i9 = {};
+            CHECK(i9[0] == 0);
+        }
 
 #ifdef CONFIRM_COMPILATION_ERRORS
-		{
-			span<int, dynamic_range> av = arr;
-			span<int, 2, 1> av2 = av.as_span(dim<2>(), dim<2>());
-		}
+        {
+            index<3> i1(0, 1);
+            index<3> i2(0, 1, 2, 3);
+            index<3> i3 = {0};
+            index<3> i4 = {0, 1, 2, 3};
+            index<1> i5 = {0, 1};
+        }
+#endif
+    }
+
+    TEST(index_operations)
+    {
+        ptrdiff_t a[3] = {0, 1, 2};
+        ptrdiff_t b[3] = {3, 4, 5};
+        index<3> i = a;
+        index<3> j = b;
+
+        CHECK(i[0] == 0);
+        CHECK(i[1] == 1);
+        CHECK(i[2] == 2);
+
+        {
+            index<3> k = i + j;
+
+            CHECK(i[0] == 0);
+            CHECK(i[1] == 1);
+            CHECK(i[2] == 2);
+            CHECK(k[0] == 3);
+            CHECK(k[1] == 5);
+            CHECK(k[2] == 7);
+        }
+
+        {
+            index<3> k = i * 3;
+
+            CHECK(i[0] == 0);
+            CHECK(i[1] == 1);
+            CHECK(i[2] == 2);
+            CHECK(k[0] == 0);
+            CHECK(k[1] == 3);
+            CHECK(k[2] == 6);
+        }
+
+        {
+            index<3> k = 3 * i;
+
+            CHECK(i[0] == 0);
+            CHECK(i[1] == 1);
+            CHECK(i[2] == 2);
+            CHECK(k[0] == 0);
+            CHECK(k[1] == 3);
+            CHECK(k[2] == 6);
+        }
+
+        {
+            index<2> k = details::shift_left(i);
+
+            CHECK(i[0] == 0);
+            CHECK(i[1] == 1);
+            CHECK(i[2] == 2);
+            CHECK(k[0] == 1);
+            CHECK(k[1] == 2);
+        }
+    }
+
+    void iterate_second_column(span<int, dynamic_range, dynamic_range> av)
+    {
+        auto length = av.size() / 2;
+
+        // view to the second column
+        auto section = av.section({0, 1}, {length, 1});
+
+        CHECK(section.size() == length);
+        for (auto i = 0; i < section.size(); ++i) {
+            CHECK(section[i][0] == av[i][1]);
+        }
+
+        for (auto i = 0; i < section.size(); ++i) {
+            auto idx = index<2>{i, 0}; // avoid braces inside the CHECK macro
+            CHECK(section[idx] == av[i][1]);
+        }
+
+        CHECK(section.bounds().index_bounds()[0] == length);
+        CHECK(section.bounds().index_bounds()[1] == 1);
+        for (auto i = 0; i < section.bounds().index_bounds()[0]; ++i) {
+            for (auto j = 0; j < section.bounds().index_bounds()[1]; ++j) {
+                auto idx = index<2>{i, j}; // avoid braces inside the CHECK macro
+                CHECK(section[idx] == av[i][1]);
+            }
+        }
+
+        size_t check_sum = 0;
+        for (auto i = 0; i < length; ++i) {
+            check_sum += av[i][1];
+        }
+
+        {
+            auto idx = 0;
+            size_t sum = 0;
+            for (auto num : section) {
+                CHECK(num == av[idx][1]);
+                sum += num;
+                idx++;
+            }
+
+            CHECK(sum == check_sum);
+        }
+        {
+            size_t idx = length - 1;
+            size_t sum = 0;
+            for (auto iter = section.rbegin(); iter != section.rend(); ++iter) {
+                CHECK(*iter == av[idx][1]);
+                sum += *iter;
+                idx--;
+            }
+
+            CHECK(sum == check_sum);
+        }
+    }
+
+    TEST(span_section_iteration)
+    {
+        int arr[4][2] = {{4, 0}, {5, 1}, {6, 2}, {7, 3}};
+
+        // static bounds
+        {
+            span<int, 4, 2> av = arr;
+            iterate_second_column(av);
+        }
+        // first bound is dynamic
+        {
+            span<int, dynamic_range, 2> av = arr;
+            iterate_second_column(av);
+        }
+        // second bound is dynamic
+        {
+            span<int, 4, dynamic_range> av = arr;
+            iterate_second_column(av);
+        }
+        // both bounds are dynamic
+        {
+            span<int, dynamic_range, dynamic_range> av = arr;
+            iterate_second_column(av);
+        }
+    }
+
+    TEST(dynamic_span_section_iteration)
+    {
+        auto height = 4, width = 2;
+        auto size = height * width;
+
+        auto arr = new int[size];
+        for (auto i = 0; i < size; ++i) {
+            arr[i] = i;
+        }
+
+        auto av = as_span(arr, size);
+
+        // first bound is dynamic
+        {
+            span<int, dynamic_range, 2> av2 = as_span(av, dim<>(height), dim<>(width));
+            iterate_second_column(av2);
+        }
+        // second bound is dynamic
+        {
+            span<int, 4, dynamic_range> av2 = as_span(av, dim<>(height), dim<>(width));
+            iterate_second_column(av2);
+        }
+        // both bounds are dynamic
+        {
+            span<int, dynamic_range, dynamic_range> av2 = as_span(av, dim<>(height), dim<>(width));
+            iterate_second_column(av2);
+        }
+
+        delete[] arr;
+    }
+
+    TEST(span_structure_size)
+    {
+        double(*arr)[3][4] = new double[100][3][4];
+        span<double, dynamic_range, 3, 4> av1(arr, 10);
+
+        struct EffectiveStructure
+        {
+            double* v1;
+            ptrdiff_t v2;
+        };
+        CHECK(sizeof(av1) == sizeof(EffectiveStructure));
+
+        CHECK_THROW(av1[10][3][4], fail_fast);
+
+        span<const double, dynamic_range, 6, 4> av2 = as_span(av1, dim<>(5), dim<6>(), dim<4>());
+        (void) av2;
+    }
+
+    TEST(fixed_size_conversions)
+    {
+        int arr[] = {1, 2, 3, 4};
+
+        // converting to an span from an equal size array is ok
+        span<int, 4> av4 = arr;
+        CHECK(av4.length() == 4);
+
+        // converting to dynamic_range a_v is always ok
+        {
+            span<int, dynamic_range> av = av4;
+            (void) av;
+        }
+        {
+            span<int, dynamic_range> av = arr;
+            (void) av;
+        }
+
+// initialization or assignment to static span that REDUCES size is NOT ok
+#ifdef CONFIRM_COMPILATION_ERRORS
+        {
+            span<int, 2> av2 = arr;
+        }
+        {
+            span<int, 2> av2 = av4;
+        }
 #endif
 
-		{
-			span<int, dynamic_range> av = arr;
-			auto f = [&]() {span<int, 2, 1> av2 = av.as_span(dim<>(2), dim<>(2)); (void)av2; };
-			CHECK_THROW(f(), fail_fast);
-		}
-
-		// but doing so explicitly is ok
-			
-		// you can convert statically
-		{
-			span<int, 2> av2 = {arr, 2};
-			(void)av2;
-		}
-		{
-			span<int, 1> av2 = av4.first<1>();
-			(void)av2;
-		}
-			
-		// ...or dynamically
-		{
-			// NB: implicit conversion to span<int,2> from span<int,dynamic_range>
-			span<int, 1> av2 = av4.first(1); 
-			(void)av2;
-		}
-
-		// initialization or assignment to static span that requires size INCREASE is not ok.
-		int arr2[2]  = { 1, 2 };
+        {
+            span<int, dynamic_range> av = arr;
+            span<int, 2> av2 = av;
+            (void) av2;
+        }
 
 #ifdef CONFIRM_COMPILATION_ERRORS
-		{
-			span<int, 4> av4 = arr2;
-		}
-		{
-			span<int, 2> av2 = arr2;
-			span<int, 4> av4 = av2;
-		}
+        {
+            span<int, dynamic_range> av = arr;
+            span<int, 2, 1> av2 = av.as_span(dim<2>(), dim<2>());
+        }
 #endif
-		{
-			auto f = [&]() {span<int, 4> av4 = {arr2, 2}; (void)av4; };
-			CHECK_THROW(f(), fail_fast);
-		}
 
-		// this should fail - we are trying to assign a small dynamic a_v to a fixed_size larger one
-		span<int, dynamic_range> av = arr2;
-		auto f = [&](){ span<int, 4> av2 = av; (void)av2; };
-		CHECK_THROW(f(), fail_fast);
-	}
+        {
+            span<int, dynamic_range> av = arr;
+            span<int, 2, 1> av2 = as_span(av, dim<>(2), dim<>(2));
+            auto workaround_macro = [&]() { return av2[{1, 0}] == 2; };
+            CHECK(workaround_macro());
+        }
 
-	TEST(AsWriteableBytes)
-	{
-		int a[] = { 1, 2, 3, 4 };
+        // but doing so explicitly is ok
+
+        // you can convert statically
+        {
+            span<int, 2> av2 = {arr, 2};
+            (void) av2;
+        }
+        {
+            span<int, 1> av2 = av4.first<1>();
+            (void) av2;
+        }
+
+        // ...or dynamically
+        {
+            // NB: implicit conversion to span<int,2> from span<int,dynamic_range>
+            span<int, 1> av2 = av4.first(1);
+            (void) av2;
+        }
+
+        // initialization or assignment to static span that requires size INCREASE is not ok.
+        int arr2[2] = {1, 2};
 
-		{
 #ifdef CONFIRM_COMPILATION_ERRORS
-			// you should not be able to get writeable bytes for const objects
-			span<const int, dynamic_range> av = a;
-			auto wav = av.as_writeable_bytes();
+        {
+            span<int, 4> av4 = arr2;
+        }
+        {
+            span<int, 2> av2 = arr2;
+            span<int, 4> av4 = av2;
+        }
 #endif
-		}
+        {
+            auto f = [&]() {
+                span<int, 4> av4 = {arr2, 2};
+                (void) av4;
+            };
+            CHECK_THROW(f(), fail_fast);
+        }
 
-		{
-			span<int, dynamic_range> av;
-			auto wav = av.as_writeable_bytes();
-			CHECK(wav.length() == av.length());
-			CHECK(wav.length() == 0);
-			CHECK(wav.bytes() == 0);
-		}
+        // this should fail - we are trying to assign a small dynamic a_v to a fixed_size larger one
+        span<int, dynamic_range> av = arr2;
+        auto f = [&]() {
+            span<int, 4> av2 = av;
+            (void) av2;
+        };
+        CHECK_THROW(f(), fail_fast);
+    }
 
-		{
-			span<int, dynamic_range> av = a;
-			auto wav = av.as_writeable_bytes();
-			CHECK(wav.data() == (byte*)&a[0]);
-			CHECK(wav.length() == sizeof(a));
-		}
-	}
+    TEST(as_writeable_bytes)
+    {
+        int a[] = {1, 2, 3, 4};
 
-	TEST(NonConstIterator)
-	{
-		int a[] = { 1, 2, 3, 4 };
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            // you should not be able to get writeable bytes for const objects
+            span<const int, dynamic_range> av = a;
+            auto wav = av.as_writeable_bytes();
+#endif
+        }
 
-		{
-			span<int, dynamic_range> av = a;
-			auto wav = av.as_writeable_bytes();
-			for (auto& b : wav)
-			{
-				b = byte(0);
-			}
-			for (size_t i = 0; i < 4; ++i)
-			{
-				CHECK(a[i] == 0);
-			}
-		}
+        {
+            span<int, dynamic_range> av;
+            auto wav = as_writeable_bytes(av);
+            CHECK(wav.length() == av.length());
+            CHECK(wav.length() == 0);
+            CHECK(wav.size_bytes() == 0);
+        }
 
-		{
-			span<int, dynamic_range> av = a;
-			for (auto& n : av)
-			{
-				n = 1;
-			}
-			for (size_t i = 0; i < 4; ++i)
-			{
-				CHECK(a[i] == 1);
-			}
-		}
-	}
+        {
+            span<int, dynamic_range> av = a;
+            auto wav = as_writeable_bytes(av);
+            CHECK(wav.data() == (byte*) &a[0]);
+            CHECK(wav.length() == sizeof(a));
+        }
+    }
 
-	TEST(ArrayViewComparison)
-	{
-		{
-			int arr[10][2];
-			auto av1 = as_span(arr);
-			span<const int, dynamic_range, 2> av2 = av1;
+    TEST(iterator)
+    {
+        int a[] = {1, 2, 3, 4};
 
-			CHECK(av1 == av2);
+        {
+            span<int, dynamic_range> av = a;
+            auto wav = as_writeable_bytes(av);
+            for (auto& b : wav) {
+                b = byte(0);
+            }
+            for (size_t i = 0; i < 4; ++i) {
+                CHECK(a[i] == 0);
+            }
+        }
 
-			span<int, 20> av3 = av1.as_span(dim<>(20));
-			CHECK(av3 == av2 && av3 == av1);
-		}
-
-		{
-			auto av1 = nullptr;
-			auto av2 = nullptr;
-			CHECK(av1 == av2);
-			CHECK(!(av1 != av2));
-			CHECK(!(av1 < av2));
-			CHECK(av1 <= av2);
-			CHECK(!(av1 > av2));
-			CHECK(av1 >= av2);
-			CHECK(av2 == av1);
-			CHECK(!(av2 != av1));
-			CHECK(!(av2 < av1));
-			CHECK(av2 <= av1);
-			CHECK(!(av2 > av1));
-			CHECK(av2 >= av1);
-		}
-
-		{
-			int arr[] = { 2, 1 }; // bigger
-
-			span<int> av1 = nullptr;
-			span<int> av2 = arr;
-
-			CHECK(av1 != av2);
-			CHECK(av2 != av1);
-			CHECK(!(av1 == av2));
-			CHECK(!(av2 == av1));
-			CHECK(av1 < av2);
-			CHECK(!(av2 < av1));
-			CHECK(av1 <= av2);
-			CHECK(!(av2 <= av1));
-			CHECK(av2 > av1);
-			CHECK(!(av1 > av2));
-			CHECK(av2 >= av1);
-			CHECK(!(av1 >= av2));
-		}
-
-		{
-			int arr1[] = { 1, 2 };
-			int arr2[] = { 1, 2 };
-			span<int> av1 = arr1;
-			span<int> av2 = arr2;
-
-			CHECK(av1 == av2);
-			CHECK(!(av1 != av2));
-			CHECK(!(av1 < av2));
-			CHECK(av1 <= av2);
-			CHECK(!(av1 > av2));
-			CHECK(av1 >= av2);
-			CHECK(av2 == av1);
-			CHECK(!(av2 != av1));
-			CHECK(!(av2 < av1));
-			CHECK(av2 <= av1);
-			CHECK(!(av2 > av1));
-			CHECK(av2 >= av1);
-		}
-
-		{
-			int arr[] = { 1, 2, 3 };
-
-			span<int> av1 = { &arr[0], 2 }; // shorter
-			span<int> av2 = arr;            // longer
-
-			CHECK(av1 != av2);
-			CHECK(av2 != av1);
-			CHECK(!(av1 == av2));
-			CHECK(!(av2 == av1));
-			CHECK(av1 < av2);
-			CHECK(!(av2 < av1));
-			CHECK(av1 <= av2);
-			CHECK(!(av2 <= av1));
-			CHECK(av2 > av1);
-			CHECK(!(av1 > av2));
-			CHECK(av2 >= av1);
-			CHECK(!(av1 >= av2));
-		}
-
-		{
-			int arr1[] = { 1, 2 }; // smaller
-			int arr2[] = { 2, 1 }; // bigger
-
-			span<int> av1 = arr1;
-			span<int> av2 = arr2;
-
-			CHECK(av1 != av2);
-			CHECK(av2 != av1);
-			CHECK(!(av1 == av2));
-			CHECK(!(av2 == av1));
-			CHECK(av1 < av2);
-			CHECK(!(av2 < av1));
-			CHECK(av1 <= av2);
-			CHECK(!(av2 <= av1));
-			CHECK(av2 > av1);
-			CHECK(!(av1 > av2));
-			CHECK(av2 >= av1);
-			CHECK(!(av1 >= av2));
-		}
-	}
+        {
+            span<int, dynamic_range> av = a;
+            for (auto& n : av) {
+                n = 1;
+            }
+            for (size_t i = 0; i < 4; ++i) {
+                CHECK(a[i] == 1);
+            }
+        }
+    }
 }
 
-int main(int, const char *[])
-{
-	return UnitTest::RunAllTests();
-}
+int main(int, const char* []) { return UnitTest::RunAllTests(); }
diff --git a/tests/strided_span_tests.cpp b/tests/strided_span_tests.cpp
new file mode 100644
index 0000000..0fbf1d7
--- /dev/null
+++ b/tests/strided_span_tests.cpp
@@ -0,0 +1,748 @@
+/////////////////////////////////////////////////////////////////////////////// 
+// 
+// Copyright (c) 2015 Microsoft Corporation. All rights reserved. 
+// 
+// This code is licensed under the MIT License (MIT). 
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 
+// THE SOFTWARE. 
+// 
+///////////////////////////////////////////////////////////////////////////////
+
+#include <UnitTest++/UnitTest++.h> 
+#include <span.h>
+
+#include <string>
+#include <vector>
+#include <list>
+#include <iostream>
+#include <memory>
+#include <map>
+
+using namespace std;
+using namespace gsl;
+
+namespace 
+{
+	struct BaseClass {};
+	struct DerivedClass : BaseClass {};
+}
+
+SUITE(strided_span_tests)
+{
+	TEST (span_section_test)
+	{
+		int a[30][4][5];
+		
+		auto av = as_span(a);
+		auto sub = av.section({15, 0, 0}, gsl::index<3>{2, 2, 2});
+		auto subsub = sub.section({1, 0, 0}, gsl::index<3>{1, 1, 1});
+		(void)subsub;
+	}
+
+	TEST(span_section)
+	{
+		std::vector<int> data(5 * 10);
+		std::iota(begin(data), end(data), 0);
+        const span<int, 5, 10> av = as_span(span<int>{data}, dim<5>(), dim<10>());
+
+		strided_span<int, 2> av_section_1 = av.section({ 1, 2 }, { 3, 4 });
+		CHECK((av_section_1[{0, 0}] == 12));
+		CHECK((av_section_1[{0, 1}] == 13));
+		CHECK((av_section_1[{1, 0}] == 22));
+		CHECK((av_section_1[{2, 3}] == 35));
+
+		strided_span<int, 2> av_section_2 = av_section_1.section({ 1, 2 }, { 2,2 });
+		CHECK((av_section_2[{0, 0}] == 24));
+		CHECK((av_section_2[{0, 1}] == 25));
+		CHECK((av_section_2[{1, 0}] == 34));
+	}
+
+	TEST(strided_span_constructors)
+	{
+		// Check stride constructor
+		{
+			int arr[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
+			const int carr[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
+
+			strided_span<int, 1> sav1{ arr, {{9}, {1}} }; // T -> T
+			CHECK(sav1.bounds().index_bounds() == index<1>{ 9 });
+			CHECK(sav1.bounds().stride() == 1);
+			CHECK(sav1[0] == 1 && sav1[8] == 9);
+
+
+			strided_span<const int, 1> sav2{ carr, {{ 4 }, { 2 }} }; // const T -> const T
+			CHECK(sav2.bounds().index_bounds() == index<1>{ 4 });
+			CHECK(sav2.bounds().strides() == index<1>{2});
+			CHECK(sav2[0] == 1 && sav2[3] == 7);
+
+			strided_span<int, 2> sav3{ arr, {{ 2, 2 },{ 6, 2 }} }; // T -> const T
+			CHECK((sav3.bounds().index_bounds() == index<2>{ 2, 2 }));
+			CHECK((sav3.bounds().strides() == index<2>{ 6, 2 }));
+			CHECK((sav3[{0, 0}] == 1 && sav3[{0, 1}] == 3 && sav3[{1, 0}] == 7));
+		}
+
+		// Check span constructor
+		{
+			int arr[] = { 1, 2 };
+
+			// From non-cv-qualified source
+			{
+				const span<int> src = arr;
+
+				strided_span<int, 1> sav{ src, {2, 1} };
+				CHECK(sav.bounds().index_bounds() == index<1>{ 2 });
+				CHECK(sav.bounds().strides() == index<1>{ 1 });
+				CHECK(sav[1] == 2);
+
+#if _MSC_VER > 1800
+				//strided_span<const int, 1> sav_c{ {src}, {2, 1} };
+				strided_span<const int, 1> sav_c{ span<const int>{src}, strided_bounds<1>{2, 1} };
+#else
+				strided_span<const int, 1> sav_c{ span<const int>{src}, strided_bounds<1>{2, 1} };
+#endif
+				CHECK(sav_c.bounds().index_bounds() == index<1>{ 2 });
+				CHECK(sav_c.bounds().strides() == index<1>{ 1 });
+				CHECK(sav_c[1] == 2);
+
+#if _MSC_VER > 1800
+				strided_span<volatile int, 1> sav_v{ src, {2, 1} };
+#else
+				strided_span<volatile int, 1> sav_v{ span<volatile int>{src}, strided_bounds<1>{2, 1} };
+#endif
+				CHECK(sav_v.bounds().index_bounds() == index<1>{ 2 });
+				CHECK(sav_v.bounds().strides() == index<1>{ 1 });
+				CHECK(sav_v[1] == 2);
+
+#if _MSC_VER > 1800
+				strided_span<const volatile int, 1> sav_cv{ src, {2, 1} };
+#else
+				strided_span<const volatile int, 1> sav_cv{ span<const volatile int>{src}, strided_bounds<1>{2, 1} };
+#endif
+				CHECK(sav_cv.bounds().index_bounds() == index<1>{ 2 });
+				CHECK(sav_cv.bounds().strides() == index<1>{ 1 });
+				CHECK(sav_cv[1] == 2);
+			}
+
+			// From const-qualified source
+			{
+				const span<const int> src{ arr };
+
+				strided_span<const int, 1> sav_c{ src, {2, 1} };
+				CHECK(sav_c.bounds().index_bounds() == index<1>{ 2 });
+				CHECK(sav_c.bounds().strides() == index<1>{ 1 });
+				CHECK(sav_c[1] == 2);
+
+#if _MSC_VER > 1800
+				strided_span<const volatile int, 1> sav_cv{ src, {2, 1} };
+#else
+				strided_span<const volatile int, 1> sav_cv{ span<const volatile int>{src}, strided_bounds<1>{2, 1} };
+#endif
+				
+				CHECK(sav_cv.bounds().index_bounds() == index<1>{ 2 });
+				CHECK(sav_cv.bounds().strides() == index<1>{ 1 });
+				CHECK(sav_cv[1] == 2);
+			}
+
+			// From volatile-qualified source
+			{
+				const span<volatile int> src{ arr };
+
+				strided_span<volatile int, 1> sav_v{ src, {2, 1} };
+				CHECK(sav_v.bounds().index_bounds() == index<1>{ 2 });
+				CHECK(sav_v.bounds().strides() == index<1>{ 1 });
+				CHECK(sav_v[1] == 2);
+
+#if _MSC_VER > 1800
+				strided_span<const volatile int, 1> sav_cv{ src, {2, 1} };
+#else
+				strided_span<const volatile int, 1> sav_cv{ span<const volatile int>{src}, strided_bounds<1>{2, 1} };
+#endif
+				CHECK(sav_cv.bounds().index_bounds() == index<1>{ 2 });
+				CHECK(sav_cv.bounds().strides() == index<1>{ 1 });
+				CHECK(sav_cv[1] == 2);
+			}
+
+			// From cv-qualified source
+			{
+				const span<const volatile int> src{ arr };
+
+				strided_span<const volatile int, 1> sav_cv{ src, {2, 1} };
+				CHECK(sav_cv.bounds().index_bounds() == index<1>{ 2 });
+				CHECK(sav_cv.bounds().strides() == index<1>{ 1 });
+				CHECK(sav_cv[1] == 2);
+			}
+		}
+
+		// Check const-casting constructor
+		{
+			int arr[2] = { 4, 5 };
+
+			const span<int, 2> av(arr, 2);
+			span<const int, 2> av2{ av };
+			CHECK(av2[1] == 5);
+
+			static_assert(std::is_convertible<const span<int, 2>, span<const int, 2>>::value, "ctor is not implicit!");
+		
+			const strided_span<int, 1> src{ arr, {2, 1} };
+			strided_span<const int, 1> sav{ src };
+			CHECK(sav.bounds().index_bounds() == index<1>{ 2 });
+			CHECK(sav.bounds().stride() == 1);
+			CHECK(sav[1] == 5);
+			
+			static_assert(std::is_convertible<const strided_span<int, 1>, strided_span<const int, 1>>::value, "ctor is not implicit!");
+		}
+
+		// Check copy constructor
+		{
+			int arr1[2] = { 3, 4 };
+			const strided_span<int, 1> src1{ arr1, {2, 1} };
+			strided_span<int, 1> sav1{ src1 };
+ 
+			CHECK(sav1.bounds().index_bounds() == index<1>{ 2 });
+			CHECK(sav1.bounds().stride() == 1);
+			CHECK(sav1[0] == 3);
+
+			int arr2[6] = { 1, 2, 3, 4, 5, 6 };
+			const strided_span<const int, 2> src2{ arr2, {{ 3, 2 }, { 2, 1 }} };
+			strided_span<const int, 2> sav2{ src2 };
+			CHECK((sav2.bounds().index_bounds() == index<2>{ 3, 2 }));
+			CHECK((sav2.bounds().strides() == index<2>{ 2, 1 }));
+			CHECK((sav2[{0, 0}] == 1 && sav2[{2, 0}] == 5));
+		}
+
+		// Check const-casting assignment operator
+		{
+			int arr1[2] = { 1, 2 };
+			int arr2[6] = { 3, 4, 5, 6, 7, 8 };
+
+			const strided_span<int, 1> src{ arr1, {{2}, {1}} };
+			strided_span<const int, 1> sav{ arr2, {{3}, {2}} };
+			strided_span<const int, 1>& sav_ref = (sav = src);
+			CHECK(sav.bounds().index_bounds() == index<1>{ 2 });
+			CHECK(sav.bounds().strides() == index<1>{ 1 });
+			CHECK(sav[0] == 1);
+			CHECK(&sav_ref == &sav);
+		}
+		
+		// Check copy assignment operator
+		{
+			int arr1[2] = { 3, 4 };
+			int arr1b[1] = { 0 };
+			const strided_span<int, 1> src1{ arr1, {2, 1} };
+			strided_span<int, 1> sav1{ arr1b, {1, 1} };
+			strided_span<int, 1>& sav1_ref = (sav1 = src1);
+			CHECK(sav1.bounds().index_bounds() == index<1>{ 2 });
+			CHECK(sav1.bounds().strides() == index<1>{ 1 });
+			CHECK(sav1[0] == 3);
+			CHECK(&sav1_ref == &sav1);
+
+			const int arr2[6] = { 1, 2, 3, 4, 5, 6 };
+			const int arr2b[1] = { 0 };
+			const strided_span<const int, 2> src2{ arr2, {{ 3, 2 },{ 2, 1 }} };
+			strided_span<const int, 2> sav2{ arr2b, {{ 1, 1 },{ 1, 1 }} };
+			strided_span<const int, 2>& sav2_ref = (sav2 = src2);
+			CHECK((sav2.bounds().index_bounds() == index<2>{ 3, 2 }));
+			CHECK((sav2.bounds().strides() == index<2>{ 2, 1 }));
+			CHECK((sav2[{0, 0}] == 1 && sav2[{2, 0}] == 5));
+			CHECK(&sav2_ref == &sav2);
+		}
+	}
+
+	TEST(strided_span_slice)
+	{
+		std::vector<int> data(5 * 10);
+		std::iota(begin(data), end(data), 0);
+        const span<int, 5, 10> src = as_span(span<int>{data}, dim<5>(), dim<10>());
+
+		const strided_span<int, 2> sav{ src, {{5, 10}, {10, 1}} };
+#ifdef CONFIRM_COMPILATION_ERRORS
+		const strided_span<const int, 2> csav{ {src},{ { 5, 10 },{ 10, 1 } } };
+#endif
+		const strided_span<const int, 2> csav{ span<const int, 5, 10>{ src }, { { 5, 10 },{ 10, 1 } } };
+
+		strided_span<int, 1> sav_sl = sav[2];
+		CHECK(sav_sl[0] == 20);
+		CHECK(sav_sl[9] == 29);
+
+		strided_span<const int, 1> csav_sl = sav[3];
+		CHECK(csav_sl[0] == 30);
+		CHECK(csav_sl[9] == 39);
+
+		CHECK(sav[4][0] == 40);
+		CHECK(sav[4][9] == 49);
+	}
+
+	TEST(strided_span_column_major)
+	{
+		// strided_span may be used to accomodate more peculiar
+		// use cases, such as column-major multidimensional array
+		// (aka. "FORTRAN" layout).
+
+		int cm_array[3 * 5] = {
+			1, 4, 7, 10, 13,
+			2, 5, 8, 11, 14,
+			3, 6, 9, 12, 15
+		};
+		strided_span<int, 2> cm_sav{ cm_array, {{ 5, 3 },{ 1, 5 }} };
+
+		// Accessing elements
+		CHECK((cm_sav[{0, 0}] == 1));
+		CHECK((cm_sav[{0, 1}] == 2));
+		CHECK((cm_sav[{1, 0}] == 4));
+		CHECK((cm_sav[{4, 2}] == 15));
+
+		// Slice
+		strided_span<int, 1> cm_sl = cm_sav[3];
+
+		CHECK(cm_sl[0] == 10);
+		CHECK(cm_sl[1] == 11);
+		CHECK(cm_sl[2] == 12);
+
+		// Section 
+		strided_span<int, 2> cm_sec = cm_sav.section( { 2, 1 }, { 3, 2 });
+
+		CHECK((cm_sec.bounds().index_bounds() == index<2>{3, 2}));
+		CHECK((cm_sec[{0, 0}] == 8));
+		CHECK((cm_sec[{0, 1}] == 9));
+		CHECK((cm_sec[{1, 0}] == 11));
+		CHECK((cm_sec[{2, 1}] == 15));
+	}
+
+	TEST(strided_span_bounds)
+	{
+		int arr[] = { 0, 1, 2, 3 };
+		span<int> av(arr);
+
+		{
+			// incorrect sections
+			
+			CHECK_THROW(av.section(0, 0)[0], fail_fast);
+			CHECK_THROW(av.section(1, 0)[0], fail_fast);
+			CHECK_THROW(av.section(1, 1)[1], fail_fast);
+			
+			CHECK_THROW(av.section(2, 5), fail_fast);
+			CHECK_THROW(av.section(5, 2), fail_fast);
+			CHECK_THROW(av.section(5, 0), fail_fast);
+			CHECK_THROW(av.section(0, 5), fail_fast);
+			CHECK_THROW(av.section(5, 5), fail_fast);
+		}
+
+		{
+			// zero stride
+			strided_span<int, 1> sav{ av,{ { 4 },{} } };
+			CHECK(sav[0] == 0);
+			CHECK(sav[3] == 0);
+			CHECK_THROW(sav[4], fail_fast);
+		}
+
+		{
+			// zero extent
+			strided_span<int, 1> sav{ av,{ {},{ 1 } } };
+			CHECK_THROW(sav[0], fail_fast);
+		}
+
+		{
+			// zero extent and stride
+			strided_span<int, 1> sav{ av,{ {},{} } };
+			CHECK_THROW(sav[0], fail_fast);
+		}
+
+		{
+			// strided array ctor with matching strided bounds 
+			strided_span<int, 1> sav{ arr,{ 4, 1 } };
+			CHECK(sav.bounds().index_bounds() == index<1>{ 4 });
+			CHECK(sav[3] == 3);
+			CHECK_THROW(sav[4], fail_fast);
+		}
+
+		{
+			// strided array ctor with smaller strided bounds 
+			strided_span<int, 1> sav{ arr,{ 2, 1 } };
+			CHECK(sav.bounds().index_bounds() == index<1>{ 2 });
+			CHECK(sav[1] == 1);
+			CHECK_THROW(sav[2], fail_fast);
+		}
+
+		{
+			// strided array ctor with fitting irregular bounds 
+			strided_span<int, 1> sav{ arr,{ 2, 3 } };
+			CHECK(sav.bounds().index_bounds() == index<1>{ 2 });
+			CHECK(sav[0] == 0);
+			CHECK(sav[1] == 3);
+			CHECK_THROW(sav[2], fail_fast);
+		}
+
+		{
+			// bounds cross data boundaries - from static arrays
+			CHECK_THROW((strided_span<int, 1> { arr, { 3, 2 } }), fail_fast);
+			CHECK_THROW((strided_span<int, 1> { arr, { 3, 3 } }), fail_fast);
+			CHECK_THROW((strided_span<int, 1> { arr, { 4, 5 } }), fail_fast);
+			CHECK_THROW((strided_span<int, 1> { arr, { 5, 1 } }), fail_fast);
+			CHECK_THROW((strided_span<int, 1> { arr, { 5, 5 } }), fail_fast);
+		}
+
+		{
+			// bounds cross data boundaries - from array view
+			CHECK_THROW((strided_span<int, 1> { av, { 3, 2 } }), fail_fast);
+			CHECK_THROW((strided_span<int, 1> { av, { 3, 3 } }), fail_fast);
+			CHECK_THROW((strided_span<int, 1> { av, { 4, 5 } }), fail_fast);
+			CHECK_THROW((strided_span<int, 1> { av, { 5, 1 } }), fail_fast);
+			CHECK_THROW((strided_span<int, 1> { av, { 5, 5 } }), fail_fast);
+		}
+
+		{
+			// bounds cross data boundaries - from dynamic arrays
+			CHECK_THROW((strided_span<int, 1> { av.data(), 4, { 3, 2 } }), fail_fast);
+			CHECK_THROW((strided_span<int, 1> { av.data(), 4, { 3, 3 } }), fail_fast);
+			CHECK_THROW((strided_span<int, 1> { av.data(), 4, { 4, 5 } }), fail_fast);
+			CHECK_THROW((strided_span<int, 1> { av.data(), 4, { 5, 1 } }), fail_fast);
+			CHECK_THROW((strided_span<int, 1> { av.data(), 4, { 5, 5 } }), fail_fast);
+			CHECK_THROW((strided_span<int, 1> { av.data(), 2, { 2, 2 } }), fail_fast);
+		}
+
+#ifdef CONFIRM_COMPILATION_ERRORS
+		{
+			strided_span<int, 1> sav0{ av.data(), { 3, 2 } };
+			strided_span<int, 1> sav1{ arr, { 1 } };
+			strided_span<int, 1> sav2{ arr, { 1,1,1 } };
+			strided_span<int, 1> sav3{ av, { 1 } };
+			strided_span<int, 1> sav4{ av, { 1,1,1 } };
+			strided_span<int, 2> sav5{ av.as_span(dim<2>(), dim<2>()), { 1 } };
+			strided_span<int, 2> sav6{ av.as_span(dim<2>(), dim<2>()), { 1,1,1 } };
+			strided_span<int, 2> sav7{ av.as_span(dim<2>(), dim<2>()), { { 1,1 },{ 1,1 },{ 1,1 } } };
+
+			index<1> index{ 0, 1 };
+			strided_span<int, 1> sav8{ arr,{ 1,{ 1,1 } } };
+			strided_span<int, 1> sav9{ arr,{ { 1,1 },{ 1,1 } } };
+			strided_span<int, 1> sav10{ av,{ 1,{ 1,1 } } };
+			strided_span<int, 1> sav11{ av,{ { 1,1 },{ 1,1 } } };
+			strided_span<int, 2> sav12{ av.as_span(dim<2>(), dim<2>()),{ { 1 },{ 1 } } };
+			strided_span<int, 2> sav13{ av.as_span(dim<2>(), dim<2>()),{ { 1 },{ 1,1,1 } } };
+			strided_span<int, 2> sav14{ av.as_span(dim<2>(), dim<2>()),{ { 1,1,1 },{ 1 } } };
+		}
+#endif
+	}
+
+	TEST(strided_span_type_conversion)
+	{
+		int arr[] = { 0, 1, 2, 3 };
+		span<int> av(arr);
+
+		{
+			strided_span<int, 1> sav{ av.data(), av.size(), { av.size() / 2, 2 } };
+#ifdef CONFIRM_COMPILATION_ERRORS
+			strided_span<long, 1> lsav1 = sav.as_strided_span<long, 1>();
+#endif
+		}
+		{
+			strided_span<int, 1> sav{ av, { av.size() / 2, 2 } };
+#ifdef CONFIRM_COMPILATION_ERRORS
+			strided_span<long, 1> lsav1 = sav.as_strided_span<long, 1>();
+#endif
+		}
+
+		span<const byte, dynamic_range> bytes = as_bytes(av);
+
+		// retype strided array with regular strides - from raw data
+		{
+			strided_bounds<2> bounds{ { 2, bytes.size() / 4 }, { bytes.size() / 2, 1 } };
+			strided_span<const byte, 2> sav2{ bytes.data(), bytes.size(), bounds };
+			strided_span<const int, 2> sav3 = sav2.as_strided_span<const int>();
+			CHECK(sav3[0][0] == 0);
+			CHECK(sav3[1][0] == 2);
+			CHECK_THROW(sav3[1][1], fail_fast);
+			CHECK_THROW(sav3[0][1], fail_fast);
+		}
+
+		// retype strided array with regular strides - from span
+		{
+			strided_bounds<2> bounds{ { 2, bytes.size() / 4 }, { bytes.size() / 2, 1 } };
+			span<const byte, 2, dynamic_range> bytes2 = as_span(bytes, dim<2>(), dim<>(bytes.size() / 2));
+			strided_span<const byte, 2> sav2{ bytes2, bounds };
+			strided_span<int, 2> sav3 = sav2.as_strided_span<int>();
+			CHECK(sav3[0][0] == 0);
+			CHECK(sav3[1][0] == 2);
+			CHECK_THROW(sav3[1][1], fail_fast);
+			CHECK_THROW(sav3[0][1], fail_fast);
+		}
+
+		// retype strided array with not enough elements - last dimension of the array is too small
+		{
+			strided_bounds<2> bounds{ { 4,2 },{ 4, 1 } };
+			span<const byte, 2, dynamic_range> bytes2 = as_span(bytes, dim<2>(), dim<>(bytes.size() / 2));
+			strided_span<const byte, 2> sav2{ bytes2, bounds };
+			CHECK_THROW(sav2.as_strided_span<int>(), fail_fast);
+		}
+
+		// retype strided array with not enough elements - strides are too small
+		{
+			strided_bounds<2> bounds{ { 4,2 },{ 2, 1 } };
+			span<const byte, 2, dynamic_range> bytes2 = as_span(bytes, dim<2>(), dim<>(bytes.size() / 2));
+			strided_span<const byte, 2> sav2{ bytes2, bounds };
+			CHECK_THROW(sav2.as_strided_span<int>(), fail_fast);
+		}
+
+		// retype strided array with not enough elements - last dimension does not divide by the new typesize
+		{
+			strided_bounds<2> bounds{ { 2,6 },{ 4, 1 } };
+			span<const byte, 2, dynamic_range> bytes2 = as_span(bytes, dim<2>(), dim<>(bytes.size() / 2));
+			strided_span<const byte, 2> sav2{ bytes2, bounds };
+			CHECK_THROW(sav2.as_strided_span<int>(), fail_fast);
+		}
+
+		// retype strided array with not enough elements - strides does not divide by the new typesize
+		{
+			strided_bounds<2> bounds{ { 2, 1 },{ 6, 1 } };
+			span<const byte, 2, dynamic_range> bytes2 = as_span(bytes, dim<2>(), dim<>(bytes.size() / 2));
+			strided_span<const byte, 2> sav2{ bytes2, bounds };
+			CHECK_THROW(sav2.as_strided_span<int>(), fail_fast);
+		}
+
+		// retype strided array with irregular strides - from raw data
+		{
+			strided_bounds<1> bounds{ bytes.size() / 2, 2 };
+			strided_span<const byte, 1> sav2{ bytes.data(), bytes.size(), bounds };
+			CHECK_THROW(sav2.as_strided_span<int>(), fail_fast);
+		}
+
+		// retype strided array with irregular strides - from span
+		{
+			strided_bounds<1> bounds{ bytes.size() / 2, 2 };
+			strided_span<const byte, 1> sav2{ bytes, bounds };
+			CHECK_THROW(sav2.as_strided_span<int>(), fail_fast);
+		}
+	}
+
+	TEST(empty_strided_spans)
+	{
+		{
+			span<int, 0> empty_av(nullptr);
+			strided_span<int, 1> empty_sav{ empty_av, { 0, 1 } };
+
+			CHECK(empty_sav.bounds().index_bounds() == index<1>{ 0 });
+			CHECK_THROW(empty_sav[0], fail_fast);
+			CHECK_THROW(empty_sav.begin()[0], fail_fast);
+			CHECK_THROW(empty_sav.cbegin()[0], fail_fast);
+
+			for (auto& v : empty_sav)
+			{
+                (void)v;
+				CHECK(false);
+			}
+		}
+
+		{
+			strided_span<int, 1> empty_sav{ nullptr, 0, { 0, 1 } };
+
+			CHECK(empty_sav.bounds().index_bounds() == index<1>{ 0 });
+			CHECK_THROW(empty_sav[0], fail_fast);
+			CHECK_THROW(empty_sav.begin()[0], fail_fast);
+			CHECK_THROW(empty_sav.cbegin()[0], fail_fast);
+
+			for (auto& v : empty_sav)
+			{
+                (void)v;
+				CHECK(false);
+			}
+		}
+	}
+
+    void iterate_every_other_element(span<int, dynamic_range> av)
+    {
+        // pick every other element
+
+        auto length = av.size() / 2;
+#if _MSC_VER > 1800
+        auto bounds = strided_bounds<1>({length}, {2});
+#else
+        auto bounds = strided_bounds<1>(index<1>{ length }, index<1>{ 2 });
+#endif
+        strided_span<int, 1> strided(&av.data()[1], av.size() - 1, bounds);
+
+        CHECK(strided.size() == length);
+        CHECK(strided.bounds().index_bounds()[0] == length);
+        for (auto i = 0; i < strided.size(); ++i)
+        {
+            CHECK(strided[i] == av[2 * i + 1]);
+        }
+
+        int idx = 0;
+        for (auto num : strided)
+        {
+            CHECK(num == av[2 * idx + 1]);
+            idx++;
+        }
+    }
+
+    TEST(strided_span_section_iteration)
+    {
+        int arr[8] = {4,0,5,1,6,2,7,3};
+
+        // static bounds
+        {
+            span<int, 8> av(arr, 8);
+            iterate_every_other_element(av);
+        }
+
+        // dynamic bounds
+        {
+            span<int, dynamic_range> av(arr, 8);
+            iterate_every_other_element(av);
+        }
+    }
+
+    TEST(dynamic_strided_span_section_iteration)
+    {
+        auto arr = new int[8];
+        for (int i = 0; i < 4; ++i)
+        {
+            arr[2 * i] = 4 + i;
+            arr[2 * i + 1] = i;
+        }
+
+        auto av = as_span(arr, 8);
+        iterate_every_other_element(av);
+
+        delete[] arr;
+    }
+
+    void iterate_second_slice(span<int, dynamic_range, dynamic_range, dynamic_range> av)
+    {
+        int expected[6] = {2,3,10,11,18,19};
+        auto section = av.section({0,1,0}, {3,1,2});
+
+        for (auto i = 0; i < section.extent<0>(); ++i)
+        {
+            for (auto j = 0; j < section.extent<1>(); ++j)
+                for (auto k = 0; k < section.extent<2>(); ++k)
+                {
+                    auto idx = index<3>{i,j,k}; // avoid braces in the CHECK macro
+                    CHECK(section[idx] == expected[2 * i + 2 * j + k]);
+                }
+        }
+
+        for (auto i = 0; i < section.extent<0>(); ++i)
+        {
+            for (auto j = 0; j < section.extent<1>(); ++j)
+                for (auto k = 0; k < section.extent<2>(); ++k)
+                    CHECK(section[i][j][k] == expected[2 * i + 2 * j + k]);
+        }
+
+        int i = 0;
+        for (auto num : section)
+        {
+            CHECK(num == expected[i]);
+            i++;
+        }
+    }
+
+    TEST(strided_span_section_iteration_3d)
+    {
+        int arr[3][4][2];
+        for (auto i = 0; i < 3; ++i)
+        {
+            for (auto j = 0; j < 4; ++j)
+                for (auto k = 0; k < 2; ++k)
+                    arr[i][j][k] = 8 * i + 2 * j + k;
+        }
+
+        {
+            span<int, 3, 4, 2> av = arr;
+            iterate_second_slice(av);
+        }
+    }
+
+    TEST(dynamic_strided_span_section_iteration_3d)
+    {
+        auto height = 12, width = 2;
+        auto size = height * width;
+
+        auto arr = new int[size];
+        for (auto i = 0; i < size; ++i)
+        {
+            arr[i] = i;
+        }
+
+        {
+            auto av = as_span(as_span(arr, 24), dim<3>(), dim<4>(), dim<2>());
+            iterate_second_slice(av);
+        }
+
+        {
+            auto av = as_span(as_span(arr, 24), dim<>(3), dim<4>(), dim<2>());
+            iterate_second_slice(av);
+        }
+
+        {
+            auto av = as_span(as_span(arr, 24), dim<3>(), dim<>(4), dim<2>());
+            iterate_second_slice(av);
+        }
+
+        {
+            auto av = as_span(as_span(arr, 24), dim<3>(), dim<4>(), dim<>(2));
+            iterate_second_slice(av);
+        }
+        delete[] arr;
+    }
+
+    TEST(strided_span_conversion)
+    {
+        // get an span of 'c' values from the list of X's
+
+        struct X { int a; int b; int c; };
+
+        X arr[4] = {{0,1,2},{3,4,5},{6,7,8},{9,10,11}};
+
+        int s = sizeof(int) / sizeof(byte);
+        auto d2 = 3 * s;
+        auto d1 = sizeof(int) * 12 / d2;
+
+        // convert to 4x12 array of bytes
+        auto av = as_span(as_bytes(as_span(arr, 4)), dim<>(d1), dim<>(d2));
+
+        CHECK(av.bounds().index_bounds()[0] == 4);
+        CHECK(av.bounds().index_bounds()[1] == 12);
+
+        // get the last 4 columns
+        auto section = av.section({0, 2 * s}, {4, s}); // { { arr[0].c[0], arr[0].c[1], arr[0].c[2], arr[0].c[3] } , { arr[1].c[0], ... } , ... }
+
+                                                       // convert to array 4x1 array of integers
+        auto cs = section.as_strided_span<int>(); // { { arr[0].c }, {arr[1].c } , ... } 
+
+        CHECK(cs.bounds().index_bounds()[0] == 4);
+        CHECK(cs.bounds().index_bounds()[1] == 1);
+
+        // transpose to 1x4 array 
+        strided_bounds<2> reverse_bounds{
+            {cs.bounds().index_bounds()[1] , cs.bounds().index_bounds()[0]},
+            {cs.bounds().strides()[1], cs.bounds().strides()[0]}
+        };
+
+        strided_span<int, 2> transposed{cs.data(), cs.bounds().total_size(), reverse_bounds};
+
+        // slice to get a one-dimensional array of c's
+        strided_span<int, 1> result = transposed[0];
+
+        CHECK(result.bounds().index_bounds()[0] == 4);
+        CHECK_THROW(result.bounds().index_bounds()[1], fail_fast);
+
+        int i = 0;
+        for (auto& num : result)
+        {
+            CHECK(num == arr[i].c);
+            i++;
+        }
+
+    }
+}
+
+int main(int, const char *[])
+{
+	return UnitTest::RunAllTests();
+}
diff --git a/tests/string_span_tests.cpp b/tests/string_span_tests.cpp
index efdf0ff..f14df93 100644
--- a/tests/string_span_tests.cpp
+++ b/tests/string_span_tests.cpp
@@ -58,25 +58,21 @@ SUITE(string_span_tests)
         {
             cwstring_span<> v = ensure_z(stack_string);
             CHECK(v.length() == 5);
-            CHECK(v.used_length() == v.length());
         }
 
         {
             cwstring_span<> v = stack_string;
             CHECK(v.length() == 6);
-            CHECK(v.used_length() == v.length());
         }
 
         {
             wstring_span<> v = ensure_z(stack_string);
             CHECK(v.length() == 5);
-            CHECK(v.used_length() == v.length());
         }
 
         {
             wstring_span<> v = stack_string;
             CHECK(v.length() == 6);
-            CHECK(v.used_length() == v.length());
         }
 	}
 
@@ -85,7 +81,6 @@ SUITE(string_span_tests)
         const char* s = "Hello";
         cstring_span<> v = ensure_z(s);
         CHECK(v.length() == 5);
-        CHECK(v.used_length() == v.length());
     }
 
     TEST(TestConversionToConst)

From c9959b107118b7adc8d615a121f94c72214cd0cd Mon Sep 17 00:00:00 2001
From: Neil MacIntosh <neilmac@microsoft.com>
Date: Mon, 30 Nov 2015 05:34:38 +0000
Subject: [PATCH 32/43] Corrected some variable naming.

---
 include/span.h       | 54 ++++++++++++++++++++++----------------------
 tests/span_tests.cpp |  4 ++--
 2 files changed, 29 insertions(+), 29 deletions(-)

diff --git a/include/span.h b/include/span.h
index 4f0de0b..fd15472 100644
--- a/include/span.h
+++ b/include/span.h
@@ -840,27 +840,27 @@ public:
     using index_size_type = typename IndexType::value_type;
     template <typename Bounds>
     explicit bounds_iterator(const Bounds& bnd, value_type curr) noexcept
-        : boundary(bnd.index_bounds()),
-          curr(std::move(curr))
+        : boundary_(bnd.index_bounds()),
+          curr_(std::move(curr))
     {
         static_assert(is_bounds<Bounds>::value, "Bounds type must be provided");
     }
 
-    constexpr reference operator*() const noexcept { return curr; }
+    constexpr reference operator*() const noexcept { return curr_; }
 
-    constexpr pointer operator->() const noexcept { return &curr; }
+    constexpr pointer operator->() const noexcept { return &curr_; }
 
     constexpr bounds_iterator& operator++() noexcept
     {
         for (size_t i = rank; i-- > 0;) {
-            if (curr[i] < boundary[i] - 1) {
-                curr[i]++;
+            if (curr_[i] < boundary_[i] - 1) {
+                curr_[i]++;
                 return *this;
             }
-            curr[i] = 0;
+            curr_[i] = 0;
         }
         // If we're here we've wrapped over - set to past-the-end.
-        curr = boundary;
+        curr_ = boundary_;
         return *this;
     }
 
@@ -873,19 +873,19 @@ public:
 
     constexpr bounds_iterator& operator--() noexcept
     {
-        if (!less(curr, boundary)) {
+        if (!less(curr_, boundary_)) {
             // if at the past-the-end, set to last element
             for (size_t i = 0; i < rank; ++i) {
-                curr[i] = boundary[i] - 1;
+                curr_[i] = boundary_[i] - 1;
             }
             return *this;
         }
         for (size_t i = rank; i-- > 0;) {
-            if (curr[i] >= 1) {
-                curr[i]--;
+            if (curr_[i] >= 1) {
+                curr_[i]--;
                 return *this;
             }
-            curr[i] = boundary[i] - 1;
+            curr_[i] = boundary_[i] - 1;
         }
         // If we're here the preconditions were violated
         // "pre: there exists s such that r == ++s"
@@ -908,18 +908,18 @@ public:
 
     constexpr bounds_iterator& operator+=(difference_type n) noexcept
     {
-        auto linear_idx = linearize(curr) + n;
+        auto linear_idx = linearize(curr_) + n;
         std::remove_const_t<value_type> stride = 0;
         stride[rank - 1] = 1;
         for (size_t i = rank - 1; i-- > 0;) {
-            stride[i] = stride[i + 1] * boundary[i + 1];
+            stride[i] = stride[i + 1] * boundary_[i + 1];
         }
         for (size_t i = 0; i < rank; ++i) {
-            curr[i] = linear_idx / stride[i];
+            curr_[i] = linear_idx / stride[i];
             linear_idx = linear_idx % stride[i];
         }
         // index is out of bounds of the array
-        Expects(!less(curr, index_type{}) && !less(boundary, curr));
+        Expects(!less(curr_, index_type{}) && !less(boundary_, curr_));
         return *this;
     }
 
@@ -933,21 +933,21 @@ public:
 
     constexpr difference_type operator-(const bounds_iterator& rhs) const noexcept
     {
-        return linearize(curr) - linearize(rhs.curr);
+        return linearize(curr_) - linearize(rhs.curr_);
     }
 
     constexpr value_type operator[](difference_type n) const noexcept { return *(*this + n); }
 
     constexpr bool operator==(const bounds_iterator& rhs) const noexcept
     {
-        return curr == rhs.curr;
+        return curr_ == rhs.curr_;
     }
 
     constexpr bool operator!=(const bounds_iterator& rhs) const noexcept { return !(*this == rhs); }
 
     constexpr bool operator<(const bounds_iterator& rhs) const noexcept
     {
-        return less(curr, rhs.curr);
+        return less(curr_, rhs.curr_);
     }
 
     constexpr bool operator<=(const bounds_iterator& rhs) const noexcept { return !(rhs < *this); }
@@ -958,8 +958,8 @@ public:
 
     void swap(bounds_iterator& rhs) noexcept
     {
-        std::swap(boundary, rhs.boundary);
-        std::swap(curr, rhs.curr);
+        std::swap(boundary_, rhs.boundary_);
+        std::swap(curr_, rhs.curr_);
     }
 
 private:
@@ -977,25 +977,25 @@ private:
         // Check if past-the-end
         index_size_type multiplier = 1;
         index_size_type res = 0;
-        if (!less(idx, boundary)) {
+        if (!less(idx, boundary_)) {
             res = 1;
             for (size_t i = rank; i-- > 0;) {
                 res += (idx[i] - 1) * multiplier;
-                multiplier *= boundary[i];
+                multiplier *= boundary_[i];
             }
         }
         else
         {
             for (size_t i = rank; i-- > 0;) {
                 res += idx[i] * multiplier;
-                multiplier *= boundary[i];
+                multiplier *= boundary_[i];
             }
         }
         return res;
     }
 
-    value_type boundary;
-    std::remove_const_t<value_type> curr;
+    value_type boundary_;
+    std::remove_const_t<value_type> curr_;
 };
 
 template <typename IndexType>
diff --git a/tests/span_tests.cpp b/tests/span_tests.cpp
index 8737db9..8b39639 100644
--- a/tests/span_tests.cpp
+++ b/tests/span_tests.cpp
@@ -1606,8 +1606,8 @@ SUITE(span_tests)
 #endif
         {
             auto f = [&]() {
-                span<int, 4> av4 = {arr2, 2};
-                (void) av4;
+                span<int, 4> av9 = {arr2, 2};
+                (void) av9;
             };
             CHECK_THROW(f(), fail_fast);
         }

From f76f73980539b978ecf54798f6e6910462405e81 Mon Sep 17 00:00:00 2001
From: Neil MacIntosh <neilmac@microsoft.com>
Date: Mon, 30 Nov 2015 18:20:14 -0800
Subject: [PATCH 33/43] Addressing #178: wrong return type for function.

---
 include/span.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/span.h b/include/span.h
index fd15472..6ee810d 100644
--- a/include/span.h
+++ b/include/span.h
@@ -327,9 +327,9 @@ namespace details
         }
 
         template <typename T, size_t Dim>
-        bool contains(const T&) const
+        size_type contains(const T&) const
         {
-            return false;
+            return -1;
         }
 
         size_type elementNum(size_t) const noexcept { return 0; }

From e3878a655658d8198fa9ad5ea9df7ad9705bd6db Mon Sep 17 00:00:00 2001
From: Anna Gringauze <annagrin@microsoft.com>
Date: Mon, 30 Nov 2015 12:24:00 -0800
Subject: [PATCH 34/43] merging with master

---
 include/span.h              |   4 +-
 include/string_span.h       | 433 +++++++++++++++++++++++++++++++++---
 tests/string_span_tests.cpp | 401 ++++++++++++++++++++++++++++++++-
 3 files changed, 798 insertions(+), 40 deletions(-)

diff --git a/include/span.h b/include/span.h
index 6ee810d..8151737 100644
--- a/include/span.h
+++ b/include/span.h
@@ -51,8 +51,8 @@
 #define GSL_MSVC_HAS_VARIADIC_CTOR_BUG
 #define GSL_MSVC_NO_SUPPORT_FOR_MOVE_CTOR_DEFAULT
 
-// noexcept is not understood
-#ifndef GSL_THROWS_ON_CONTRACT_VIOLATION
+// noexcept is not understood 
+#ifndef GSL_THROW_ON_CONTRACT_VIOLATION
 #pragma push_macro("noexcept")
 #define noexcept /* nothing */
 #endif
diff --git a/include/string_span.h b/include/string_span.h
index 250c528..b11dd9e 100644
--- a/include/string_span.h
+++ b/include/string_span.h
@@ -23,15 +23,37 @@
 #include "span.h"
 #include <cstring>
 
-// VS 2013 workarounds
 #ifdef _MSC_VER
+
+// No MSVC does constexpr fully yet
+#pragma push_macro("constexpr")
+#define constexpr /* nothing */
+
+// VS 2013 workarounds
 #if _MSC_VER <= 1800
 
 #define GSL_MSVC_HAS_TYPE_DEDUCTION_BUG 
 
+// noexcept is not understood 
+#ifndef GSL_THROW_ON_CONTRACT_VIOLATION
+#pragma push_macro("noexcept")
+#define noexcept /* nothing */ 
+#endif
+
 #endif // _MSC_VER <= 1800
 #endif // _MSC_VER
 
+// In order to test the library, we need it to throw exceptions that we can catch
+#ifdef GSL_THROW_ON_CONTRACT_VIOLATION
+
+#ifdef _MSC_VER
+#pragma push_macro("noexcept")
+#endif
+
+#define noexcept /* nothing */ 
+
+#endif // GSL_THROW_ON_CONTRACT_VIOLATION 
+
 namespace gsl
 {
 //
@@ -56,27 +78,6 @@ using zstring = char*;
 template<std::ptrdiff_t Extent = dynamic_range>
 using wzstring = wchar_t*;
 
-//
-// string_span and relatives
-//
-// Note that Extent is always single-dimension only
-//
-template <class CharT, std::ptrdiff_t Extent = dynamic_range>
-using basic_string_span = span<CharT, Extent>;
-
-template<std::ptrdiff_t Extent = dynamic_range>
-using string_span = basic_string_span<char, Extent>;
-
-template<std::ptrdiff_t Extent = dynamic_range>
-using cstring_span = basic_string_span<const char, Extent>;
-
-template<std::ptrdiff_t Extent = dynamic_range>
-using wstring_span = basic_string_span<wchar_t, Extent>;
-
-template<std::ptrdiff_t Extent = dynamic_range>
-using cwstring_span = basic_string_span<const wchar_t, Extent>;
-
-
 //
 // ensure_sentinel() 
 //
@@ -86,7 +87,7 @@ using cwstring_span = basic_string_span<const wchar_t, Extent>;
 // Will fail-fast if sentinel cannot be found before max elements are examined.
 //
 template<class T, const T Sentinel>
-span<T, dynamic_range> ensure_sentinel(const T* seq, std::ptrdiff_t max = PTRDIFF_MAX)
+span<T, dynamic_range> ensure_sentinel(T* seq, std::ptrdiff_t max = PTRDIFF_MAX)
 {
     auto cur = seq;
     while ((cur - seq) < max && *cur != Sentinel) ++cur;
@@ -101,46 +102,341 @@ span<T, dynamic_range> ensure_sentinel(const T* seq, std::ptrdiff_t max = PTRDIF
 // the limit of size_type.
 //
 template<class T>
-inline basic_string_span<T, dynamic_range> ensure_z(T* const & sz, std::ptrdiff_t max = PTRDIFF_MAX)
+inline span<T, dynamic_range> ensure_z(T* const & sz, std::ptrdiff_t max = PTRDIFF_MAX)
 {
     return ensure_sentinel<T, 0>(sz, max);
 }
 
 // TODO (neilmac) there is probably a better template-magic way to get the const and non-const overloads to share an implementation
-inline basic_string_span<char, dynamic_range> ensure_z(char* const& sz, std::ptrdiff_t max)
+inline span<char, dynamic_range> ensure_z(char* const& sz, std::ptrdiff_t max)
 {
     auto len = strnlen(sz, max);
     Ensures(sz[len] == 0);
     return{ sz, static_cast<std::ptrdiff_t>(len) };
 }
 
-inline basic_string_span<const char, dynamic_range> ensure_z(const char* const& sz, std::ptrdiff_t max)
+inline span<const char, dynamic_range> ensure_z(const char* const& sz, std::ptrdiff_t max)
 {
     auto len = strnlen(sz, max);
     Ensures(sz[len] == 0); return{ sz, static_cast<std::ptrdiff_t>(len) };
 }
 
-inline basic_string_span<wchar_t, dynamic_range> ensure_z(wchar_t* const& sz, std::ptrdiff_t max)
+inline span<wchar_t, dynamic_range> ensure_z(wchar_t* const& sz, std::ptrdiff_t max)
 {
     auto len = wcsnlen(sz, max);
     Ensures(sz[len] == 0); return{ sz, static_cast<std::ptrdiff_t>(len) };
 }
 
-inline basic_string_span<const wchar_t, dynamic_range> ensure_z(const wchar_t* const& sz, std::ptrdiff_t max)
+inline span<const wchar_t, dynamic_range> ensure_z(const wchar_t* const& sz, std::ptrdiff_t max)
 {
     auto len = wcsnlen(sz, max);
     Ensures(sz[len] == 0); return{ sz, static_cast<std::ptrdiff_t>(len) };
 }
 
 template<class T, size_t N>
-basic_string_span<T, dynamic_range> ensure_z(T(&sz)[N]) { return ensure_z(&sz[0], static_cast<std::ptrdiff_t>(N)); }
+span<T, dynamic_range> ensure_z(T(&sz)[N]) { return ensure_z(&sz[0], static_cast<std::ptrdiff_t>(N)); }
 
 template<class Cont>
-basic_string_span<typename std::remove_pointer<typename Cont::pointer>::type, dynamic_range> ensure_z(Cont& cont)
+span<typename std::remove_pointer<typename Cont::pointer>::type, dynamic_range> ensure_z(Cont& cont)
 {
     return ensure_z(cont.data(), static_cast<std::ptrdiff_t>(cont.length()));
 }
 
+
+// TODO (neilmac) there is probably a better template-magic way to get the const and non-const overloads to share an implementation
+inline span<char, dynamic_range> remove_z(char* const& sz, std::ptrdiff_t max)
+{
+    auto len = strnlen(sz, max);
+    return{ sz, static_cast<std::ptrdiff_t>(len) };
+}
+
+inline span<const char, dynamic_range> remove_z(const char* const& sz, std::ptrdiff_t max)
+{
+    auto len = strnlen(sz, max);
+    return{ sz, static_cast<std::ptrdiff_t>(len) };
+}
+
+inline span<wchar_t, dynamic_range> remove_z(wchar_t* const& sz, std::ptrdiff_t max)
+{
+    auto len = wcsnlen(sz, max);
+    return{ sz, static_cast<std::ptrdiff_t>(len) };
+}
+
+inline span<const wchar_t, dynamic_range> remove_z(const wchar_t* const& sz, std::ptrdiff_t max)
+{
+    auto len = wcsnlen(sz, max);
+    return{ sz, static_cast<std::ptrdiff_t>(len) };
+}
+
+template<class T, size_t N>
+span<T, dynamic_range> remove_z(T(&sz)[N])
+{
+    return remove_z(&sz[0], static_cast<std::ptrdiff_t>(N));
+}
+
+template<class Cont>
+span<typename std::remove_pointer<typename Cont::pointer>::type, dynamic_range> remove_z(Cont& cont)
+{
+    return remove_z(cont.data(), static_cast<std::ptrdiff_t>(cont.length()));
+}
+
+template<typename ValueType, std::ptrdiff_t>
+class basic_string_span;
+
+namespace details
+{
+    template <typename T>
+    struct is_basic_string_span_oracle : std::false_type
+    {};
+
+    template <typename ValueType, std::ptrdiff_t Extent>
+    struct is_basic_string_span_oracle<basic_string_span<ValueType, Extent>> : std::true_type
+    {};
+
+    template <typename T>
+    struct is_basic_string_span : is_basic_string_span_oracle<std::remove_cv_t<T>>
+    {};
+}
+
+//
+// string_span and relatives
+//
+// Note that Extent is always single-dimension only
+//
+template <class CharT, std::ptrdiff_t Extent = dynamic_range>
+class basic_string_span
+{
+    using value_type = CharT;
+    using const_value_type = std::add_const_t<value_type>;
+    using pointer = std::add_pointer_t<value_type>;
+    using reference = std::add_lvalue_reference_t<value_type>;
+    using const_reference = std::add_lvalue_reference_t<const_value_type>;
+    using bounds_type = static_bounds<Extent>;
+    using underlying_type = span<value_type, Extent>;
+
+public:
+    using size_type = ptrdiff_t;
+    using iterator = typename underlying_type::iterator;
+    using const_iterator = typename underlying_type::const_iterator;
+    using reverse_iterator = typename underlying_type::reverse_iterator;
+    using const_reverse_iterator = typename underlying_type::const_reverse_iterator;
+
+    // empty
+    constexpr basic_string_span() noexcept
+        : real(nullptr)
+    {}
+
+    // copy
+    constexpr basic_string_span(const basic_string_span& other) noexcept
+        : real(other.real)
+    {}
+
+    // move
+    constexpr basic_string_span(const basic_string_span&& other) noexcept
+        : real(std::move(other.real))
+    {}
+
+    // from nullptr and length
+    constexpr basic_string_span(nullptr_t ptr, size_type length) noexcept
+        : real(ptr, length)
+    {}
+
+    // For pointers and static arrays - if 0-terminated, remove 0 from the view
+
+    // from c string
+    
+    constexpr basic_string_span(pointer& ptr) noexcept
+        : real(ensure_z(ptr))
+    {}
+
+    // from non-const pointer to const span
+    template<typename Dummy = std::enable_if_t<std::is_const<value_type>::value>>
+    constexpr basic_string_span(std::remove_const_t<value_type>*& ptr) noexcept
+        : real(ensure_z(ptr))
+    {}
+
+    // from raw data and length - remove 0 if needed
+    constexpr basic_string_span(pointer ptr, size_type length) noexcept
+        : real(remove_z(ptr, length))
+    {}
+
+    // from static arrays and string literals
+    template<size_t N>
+    constexpr basic_string_span(value_type(&arr)[N]) noexcept
+        : real(remove_z(arr))
+    {}
+
+    // Those allow 0s in the middle, so we keep them
+
+    constexpr basic_string_span(std::string& s) noexcept
+        : real(&(s.at(0)), static_cast<ptrdiff_t>(s.length()))
+    {}
+
+    // from containers. It must have .size() and .data() function signatures
+    template <typename Cont, typename DataType = typename Cont::value_type,
+        typename Dummy = std::enable_if_t<!details::is_span<Cont>::value
+        && !details::is_basic_string_span<Cont>::value 
+        && !(!std::is_const<value_type>::value && std::is_const<Cont>::value) // no converting const containers to non-const span
+        && std::is_convertible<DataType*, value_type*>::value
+        && std::is_same<std::decay_t<decltype(std::declval<Cont>().size(), *std::declval<Cont>().data())>, DataType>::value>
+    >
+    constexpr basic_string_span(Cont& cont)
+        : real(cont.data(), cont.size())
+    {}
+
+    // from span
+    template <typename OtherValueType, std::ptrdiff_t OtherExtent,
+        typename OtherBounds = static_bounds<OtherExtent>,
+        typename Dummy = std::enable_if_t<std::is_convertible<OtherValueType*, value_type*>::value && std::is_convertible<OtherBounds, bounds_type>::value>
+    >
+    constexpr basic_string_span(const span<OtherValueType, OtherExtent>& other) noexcept
+        : real(other)
+    {}
+
+    // from string_span
+    template <typename OtherValueType, std::ptrdiff_t OtherExtent,
+        typename OtherBounds = static_bounds<OtherExtent>,
+        typename Dummy = std::enable_if_t<std::is_convertible<OtherValueType*, value_type*>::value && std::is_convertible<OtherBounds, bounds_type>::value>
+    >
+    constexpr basic_string_span(const basic_string_span<OtherValueType, OtherExtent>& other) noexcept
+        : real(other.data(), other.length())
+    {}
+
+    // section on linear space
+    template<size_type Count>
+    constexpr basic_string_span<value_type, Count> first() const noexcept
+    {
+        return{ real.first<Count>() };
+    }
+
+    constexpr basic_string_span<value_type, dynamic_range> first(size_type count) const noexcept
+    {
+        return{ real.first(count); }
+    }
+
+    template<size_type Count>
+    constexpr basic_string_span<value_type, Count> last() const noexcept
+    {
+        return{ real.last<Count>() };
+    }
+
+    constexpr basic_string_span<value_type, dynamic_range> last(size_type count) const noexcept
+    {
+        return{ real.last(count); }
+    }
+
+    template<size_type Offset, size_type Count>
+    constexpr basic_string_span<value_type, Count> sub() const noexcept
+    {
+        return{ real.sub<Count>() };
+    }
+
+    constexpr basic_string_span<value_type, dynamic_range> sub(size_type offset, size_type count = dynamic_range) const noexcept
+    {
+        return{ real.sub(offset, count) };
+    }
+
+    constexpr const_reference operator[](size_type idx) const noexcept
+    {
+        return real[idx];
+    }
+
+    constexpr reference operator[](size_type idx) noexcept
+    {
+        return real[idx];
+    }
+
+    constexpr pointer data() const noexcept
+    {
+        return real.data();
+    }
+
+    constexpr size_type length() const noexcept
+    {
+        return real.size();
+    }
+
+    constexpr size_type size() const noexcept
+    {
+        return real.size();
+    }
+
+    constexpr size_type used_length() const noexcept
+    {
+        return length();
+    }
+
+    constexpr size_type bytes() const noexcept
+    {
+        return real.bytes();
+    }
+
+    constexpr size_type used_bytes() const noexcept
+    {
+        return bytes();
+    }
+
+    constexpr explicit operator bool() const noexcept
+    {
+        return real;
+    }
+
+    constexpr iterator begin() const noexcept
+    {
+        return real.begin();
+    }
+
+    constexpr iterator end() const noexcept
+    {
+        return real.end();
+    }
+
+    constexpr const_iterator cbegin() const noexcept
+    {
+        return real.cbegin();
+    }
+
+    constexpr const_iterator cend() const noexcept
+    {
+        real.cend();
+    }
+
+    constexpr reverse_iterator rbegin() const noexcept
+    {
+        return real.rbegin();
+    }
+
+    constexpr reverse_iterator rend() const noexcept
+    {
+        return real.rend();
+    }
+
+    constexpr const_reverse_iterator crbegin() const noexcept
+    {
+        return real.crbegin();
+    }
+
+    constexpr const_reverse_iterator crend() const noexcept
+    {
+        return real.crend();
+    }
+
+private:
+    span<CharT, Extent> real;
+};
+
+template<std::ptrdiff_t Extent = dynamic_range>
+using string_span = basic_string_span<char, Extent>;
+
+template<std::ptrdiff_t Extent = dynamic_range>
+using cstring_span = basic_string_span<const char, Extent>;
+
+template<std::ptrdiff_t Extent = dynamic_range>
+using wstring_span = basic_string_span<wchar_t, Extent>;
+
+template<std::ptrdiff_t Extent = dynamic_range>
+using cwstring_span = basic_string_span<const wchar_t, Extent>;
+
 //
 // to_string() allow (explicit) conversions from string_span to string
 //
@@ -213,14 +509,89 @@ template <size_t Max = dynamic_range>
 using wzstring_builder = basic_zstring_builder<wchar_t, Max>;
 }
 
+
+constexpr bool operator==(const gsl::cstring_span<>& one, const gsl::cstring_span<>& other) noexcept
+{
+    return std::equal(one.begin(), one.end(), other.begin(), other.end());
+}
+
+constexpr bool operator==(const gsl::string_span<>& one, const gsl::string_span<>& other) noexcept
+{
+    return std::equal(one.begin(), one.end(), other.begin(), other.end());
+}
+
+
+// TODO: ca we make twmplate ops work?
+//template <typename ValueType, std::ptrdiff_t Extent>
+//constexpr bool operator==(const gsl::basic_string_span<ValueType, Extent>& one, const gsl::basic_string_span<ValueType, Extent>& other) noexcept
+//{
+//    return std::equal(one.begin(), one.end(), other.begin(), other.end());
+//}
+/*
+template <typename ValueType, std::ptrdiff_t Extent, typename OtherValueType, std::ptrdiff_t OtherExtent, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<ValueType>, std::remove_cv_t<OtherValueType>>::value>>
+constexpr bool operator==(const gsl::basic_string_span<ValueType, Extent>& one, const gsl::basic_string_span<OtherValueType, OtherExtent>& other) noexcept
+{
+    return std::equal(one.begin(), one.end(), other.begin(), other.end());
+}
+
+template <typename ValueType, std::ptrdiff_t Extent, typename OtherValueType, std::ptrdiff_t OtherExtent, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<ValueType>, std::remove_cv_t<OtherValueType>>::value>>
+constexpr bool operator!=(const gsl::basic_string_span<ValueType, Extent>& one, const gsl::basic_string_span<OtherValueType, OtherExtent>& other) noexcept
+{
+    return !(one == other);
+}
+
+template <typename ValueType, std::ptrdiff_t Extent, typename OtherValueType, std::ptrdiff_t OtherExtent, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<ValueType>, std::remove_cv_t<OtherValueType>>::value>>
+constexpr bool operator<(const gsl::basic_string_span<ValueType, Extent>& one, const gsl::basic_string_span<OtherValueType, OtherExtent>& other) noexcept
+{
+    return std::lexicographical_compare(one.begin(), one.end(), other.begin(), other.end());
+}
+
+template <typename ValueType, std::ptrdiff_t Extent, typename OtherValueType, std::ptrdiff_t OtherExtent, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<ValueType>, std::remove_cv_t<OtherValueType>>::value>>
+constexpr bool operator<=(const gsl::basic_string_span<ValueType, Extent>& one, const gsl::basic_string_span<OtherValueType, OtherExtent>& other) noexcept
+{
+    return !(other < one);
+}
+
+template <typename ValueType, std::ptrdiff_t Extent, typename OtherValueType, std::ptrdiff_t OtherExtent, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<ValueType>, std::remove_cv_t<OtherValueType>>::value>>
+constexpr bool operator>(const gsl::basic_string_span<ValueType, Extent>& one, const gsl::basic_string_span<OtherValueType, OtherExtent>& other) noexcept
+{
+    return other < one;
+}
+
+template <typename ValueType, std::ptrdiff_t Extent, typename OtherValueType, std::ptrdiff_t OtherExtent, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<ValueType>, std::remove_cv_t<OtherValueType>>::value>>
+constexpr bool operator>=(const gsl::basic_string_span<ValueType, Extent>& one, const gsl::basic_string_span<OtherValueType, OtherExtent>& other) noexcept
+{
+    return !(one < other);
+}
+*/
 // VS 2013 workarounds
 #ifdef _MSC_VER
+
+#undef constexpr
+#pragma pop_macro("constexpr")
+
 #if _MSC_VER <= 1800
 
-#undef GSL_MSVC_HAS_TYPE_DEDUCTION_BUG 
+#pragma warning(pop)
+
+#ifndef GSL_THROW_ON_CONTRACT_VIOLATION
+#undef noexcept
+#pragma pop_macro("noexcept")
+#endif // GSL_THROW_ON_CONTRACT_VIOLATION
+
+#undef GSL_MSVC_HAS_TYPE_DEDUCTION_BUG
 
 #endif // _MSC_VER <= 1800
 #endif // _MSC_VER
 
+#if defined(GSL_THROW_ON_CONTRACT_VIOLATION) 
+
+#undef noexcept
+
+#ifdef _MSC_VER
+#pragma pop_macro("noexcept")
+#endif
+
+#endif // GSL_THROW_ON_CONTRACT_VIOLATION
 
 #endif // GSL_STRING_SPAN_H
diff --git a/tests/string_span_tests.cpp b/tests/string_span_tests.cpp
index f14df93..08faaa8 100644
--- a/tests/string_span_tests.cpp
+++ b/tests/string_span_tests.cpp
@@ -18,6 +18,8 @@
 #include <string_span.h>
 #include <vector>
 #include <cstdlib>
+#include <map>
+#include <unordered_map>
 
 using namespace std;
 using namespace gsl;
@@ -27,7 +29,7 @@ SUITE(string_span_tests)
 {
 
     TEST(TestLiteralConstruction)
-	{
+    {
         cwstring_span<> v = ensure_z(L"Hello");
 
         CHECK(5 == v.length());
@@ -35,7 +37,7 @@ SUITE(string_span_tests)
 #ifdef CONFIRM_COMPILATION_ERRORS
         wstring_span<> v2 = ensure0(L"Hello");
 #endif
-	}
+    }
 
     TEST(TestConstructFromStdString)
     {
@@ -51,8 +53,8 @@ SUITE(string_span_tests)
         CHECK(v.length() == static_cast<string_span<>::size_type>(vec.size()));
     }
 
-	TEST(TestStackArrayConstruction)
-	{
+    TEST(TestStackArrayConstruction)
+    {
         wchar_t stack_string[] = L"Hello";
 
         {
@@ -62,7 +64,7 @@ SUITE(string_span_tests)
 
         {
             cwstring_span<> v = stack_string;
-            CHECK(v.length() == 6);
+            CHECK(v.length() == 5);
         }
 
         {
@@ -72,7 +74,7 @@ SUITE(string_span_tests)
 
         {
             wstring_span<> v = stack_string;
-            CHECK(v.length() == 6);
+            CHECK(v.length() == 5);
         }
 	}
 
@@ -95,7 +97,7 @@ SUITE(string_span_tests)
     {
         char stack_string[] = "Hello";
         cstring_span<> v = ensure_z(stack_string);
-	(void)v;
+        (void)v;
 #ifdef CONFIRM_COMPILATION_ERRORS
         string_span<> v2 = v;
         string_span<> v3 = "Hello";
@@ -113,6 +115,391 @@ SUITE(string_span_tests)
         CHECK(static_cast<cstring_span<>::size_type>(s2.length()) == v.length());
         CHECK(s2.length() == 5);
     }
+
+    TEST(ComparisonAndImplicitConstructors)
+    {
+        {
+            cstring_span<> span = "Hello";
+
+            const char ar[] = { 'H', 'e', 'l', 'l', 'o' };
+            const char ar1[] = "Hello";
+            const char ar2[10] = "Hello";
+            const char* ptr = "Hello";
+            const std::string str = "Hello";
+            const std::vector<char> vec = { 'H', 'e', 'l', 'l', 'o' };
+
+            // comparison to  literal
+            CHECK(span == cstring_span<>("Hello"));
+
+            // comparison to static array with no null termination
+            CHECK(span == cstring_span<>(ar)); 
+
+            // comparison to static array with null at the end
+            CHECK(span == cstring_span<>(ar1));
+
+            // comparison to static array with null in the middle
+            CHECK(span == cstring_span<>(ar2)); 
+
+            // comparison to null-terminated c string
+            CHECK(span == cstring_span<>(ptr, 5)); 
+
+            // comparison to string
+            CHECK(span == cstring_span<>(str)); 
+
+            // comparison to vector of charaters with no null termination
+            CHECK(span == cstring_span<>(vec)); 
+
+            // comparison of the original data to string
+            CHECK(span.data() == std::string("Hello"));
+
+            CHECK(span == "Hello");
+            CHECK(span == ar);
+            CHECK(span == ar1);
+            CHECK(span == ar2);
+            CHECK(span == ptr);
+            CHECK(span == str);
+            CHECK(span == vec);
+            
+            char _ar[] = { 'H', 'e', 'l', 'l', 'o' };
+            char _ar1[] = "Hello";
+            char _ar2[10] = "Hello";
+            char* _ptr = _ar1;
+            std::string _str = "Hello";
+            std::vector<char> _vec = { 'H', 'e', 'l', 'l', 'o' };
+
+            CHECK(span == _ar);
+            CHECK(span == _ar1);
+            CHECK(span == _ar2);
+            CHECK(span == _ptr);
+            CHECK(span == _str);
+            CHECK(span == _vec);
+
+            string_span<> _span{ _ptr };
+
+            CHECK(_span == _ar);
+            CHECK(_span == _ar1);
+            CHECK(_span == _ar2);
+            CHECK(_span == _ptr);
+            CHECK(_span == _str);
+            CHECK(_span == _vec);
+
+            CHECK(_span == "Hello");
+            CHECK(_span == ar);
+            CHECK(_span == ar1);
+            CHECK(_span == ar2);
+            CHECK(_span == ptr);
+            CHECK(_span == str);
+            CHECK(_span == vec);
+        }
+
+        {
+            std::vector<char> str1 = { 'H', 'e', 'l', 'l', 'o' };
+            cstring_span<> span1 = str1;
+            std::vector<char> str2 = std::move(str1);
+            cstring_span<> span2 = str2;
+
+            // comparison of spans from the same vector before and after move (ok)
+            CHECK(span1 == span2);
+        }
+    }
+
+    TEST(EnzureRemoveZ)
+    {
+        // remove z from literals
+        {
+            cstring_span<> sp = "hello";
+            CHECK((sp.length() == 5));
+        }
+
+        // take the string as is
+        {
+            auto str = std::string("hello");
+            cstring_span<> sp = str;
+            CHECK((sp.length() == 5));
+        }
+
+        // ensure z on c strings
+        {
+            char* ptr = new char[3];
+
+            ptr[0] = 'a';
+            ptr[1] = 'b';
+            ptr[2] = '\0';
+
+            string_span<> span(ptr);
+            CHECK(span.length() == 2);
+
+            delete[] ptr;
+        }
+
+        // ensuze z on c strings
+        {
+            char* ptr = new char[2];
+
+            ptr[0] = 'a';
+            ptr[1] = 'b';
+
+            // do we want to have a constructor from pointer at all?
+            // the behavior is unpredictable if the string is not 0-terminated
+
+            // CHECK_THROW((string_span<>(ptr).length() == 2), fail_fast);
+
+            cstring_span<> sp1{ ptr, 2 }; // good
+            cstring_span<> sp2{ ptr, 3 }; // bad... but can't help there
+
+            CHECK(sp1[1] == 'b');
+            CHECK_THROW((sp1[2] == 'c'), fail_fast);
+
+            CHECK(sp2[1] == 'b');
+            //CHECK_THROW((sp1[2] == 'c'), fail_fast); // buffer overflow
+
+            delete[] ptr;
+        }
+    }
+
+    TEST(Constructors)
+    {
+        // from string temporary
+#ifdef CONFIRM_COMPILATION_ERRORS
+        {
+            cstring_span<> span = std::string("Hello");
+        }
+#endif
+
+        // from string literal
+        {
+            cstring_span<> span = "Hello";
+            CHECK(span.length() == 5);
+        }
+
+        // from const static array
+        {
+            const char ar[] = { 'H', 'e', 'l', 'l', 'o' };
+            cstring_span<> span = ar;
+            CHECK(span.length() == 5);
+        }
+
+        // from non-const static array
+        {
+            char ar[] = { 'H', 'e', 'l', 'l', 'o' };
+            cstring_span<> span = ar;
+            CHECK(span.length() == 5);
+        }
+
+        // from const ptr and length
+        {
+            const char* ptr = "Hello";
+            cstring_span<> span{ ptr, 5 };
+            CHECK(span.length() == 5);
+        }
+
+        // from non-const ptr and length
+        {
+            char* ptr = "Hello";
+            cstring_span<> span{ ptr, 5 };
+            CHECK(span.length() == 5);
+        }
+
+        // from const string
+        {
+            const std::string str = "Hello";
+            cstring_span<> span = str;
+            CHECK(span.length() == 5);
+        }
+
+        // from non-const string
+        {
+            std::string str = "Hello";
+            cstring_span<> span = str;
+            CHECK(span.length() == 5);
+        }
+
+        // from const vector
+        {
+            const std::vector<char> vec = { 'H', 'e', 'l', 'l', 'o' };
+            cstring_span<> span = vec;
+            CHECK(span.length() == 5);
+        }
+
+        // from non-const vector
+        {
+            std::vector<char> vec = { 'H', 'e', 'l', 'l', 'o' };
+            cstring_span<> span = vec;
+            CHECK(span.length() == 5);
+        }
+
+        // from const span
+        {
+            std::vector<char> vec = { 'H', 'e', 'l', 'l', 'o' };
+            const span<const char> inner = vec;
+            cstring_span<> span = inner;
+            CHECK(span.length() == 5);
+        }
+
+        // from non-const span
+        {
+            std::vector<char> vec = { 'H', 'e', 'l', 'l', 'o' };
+            span<char> inner = vec;
+            cstring_span<> span = inner;
+            CHECK(span.length() == 5);
+        }
+
+        // from const string_span
+        {
+            std::vector<char> vec = { 'H', 'e', 'l', 'l', 'o' };
+            cstring_span<> tmp = vec;
+            cstring_span<> span = tmp;
+            CHECK(span.length() == 5);
+        }
+
+        // from non-const string_span
+        {
+            std::vector<char> vec = { 'H', 'e', 'l', 'l', 'o' };
+            string_span<> tmp = vec;
+            cstring_span<> span = tmp;
+            CHECK(span.length() == 5);
+        }
+
+        ///////////////////////////////////////////////////
+        // How string_span should behave with const data
+
+        // from string literal
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            string_span<> span = "Hello";
+            CHECK(span.length() == 5);
+#endif
+        }
+
+        // from const static array
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            const char ar[] = { 'H', 'e', 'l', 'l', 'o' };
+            string_span<> span = ar;
+            CHECK(span.length() == 5);
+#endif
+        }
+
+        // from non-const static array
+        {
+            char ar[] = { 'H', 'e', 'l', 'l', 'o' };
+            string_span<> span = ar;
+            CHECK(span.length() == 5);
+        }
+
+        // from const ptr and length
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            const char* ptr = "Hello";
+            string_span<> span{ ptr, 5 };
+            CHECK(span.length() == 5);
+#endif
+        }
+
+        // from non-const ptr and length
+        {
+            char* ptr = "Hello";
+            string_span<> span{ ptr, 5 };
+            CHECK(span.length() == 5);
+        }
+
+        // from const string
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            const std::string str = "Hello";
+            string_span<> span = str;
+            CHECK(span.length() == 5);
+#endif
+        }
+
+        // from non-const string
+        {
+            std::string str = "Hello";
+            string_span<> span = str;
+            CHECK(span.length() == 5);
+        }
+
+        // from const vector
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            const std::vector<char> vec = { 'H', 'e', 'l', 'l', 'o' };
+            string_span<> span = vec;
+            CHECK(span.length() == 5);
+#endif
+        }
+
+        // from non-const vector
+        {
+            std::vector<char> vec = { 'H', 'e', 'l', 'l', 'o' };
+            string_span<> span = vec;
+            CHECK(span.length() == 5);
+        }
+
+        // from const span
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            std::vector<char> vec = { 'H', 'e', 'l', 'l', 'o' };
+            const span<const char> inner = vec;
+            string_span<> span = inner;
+            CHECK(span.length() == 5);
+#endif
+        }
+
+        // from non-const span
+        {
+            std::vector<char> vec = { 'H', 'e', 'l', 'l', 'o' };
+            span<char> inner = vec;
+            string_span<> span = inner;
+            CHECK(span.length() == 5);
+        }
+
+        // from non-const span of non-const data from const vector (looks like a bug)
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            const std::vector<char> vec = { 'H', 'e', 'l', 'l', 'o' };
+            const span<char> inner = vec; // fix error (happens inside the constructor)
+            string_span<> span = inner;
+            CHECK(span.length() == 5);
+#endif
+        }
+
+        // from const string_span
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            std::vector<char> vec = { 'H', 'e', 'l', 'l', 'o' };
+            cstring_span<> tmp = vec;
+            string_span<> span = tmp;
+            CHECK(span.length() == 5);
+#endif
+        }
+
+        // from non-const string_span
+        {
+            std::vector<char> vec = { 'H', 'e', 'l', 'l', 'o' };
+            string_span<> tmp = vec;
+            string_span<> span = tmp;
+            CHECK(span.length() == 5);
+        }
+
+        // from non-const string_span from const vector
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            const std::vector<char> vec = { 'H', 'e', 'l', 'l', 'o' };
+            string_span<> tmp = vec;
+            string_span<> span = tmp;
+            CHECK(span.length() == 5);
+#endif
+        }
+
+        // from const string_span of non-const data
+        {
+            std::vector<char> vec = { 'H', 'e', 'l', 'l', 'o' };
+            const string_span<> tmp = vec; // what does "const span" mean?
+            string_span<> span = tmp;
+            CHECK(span.length() == 5);
+        }
+    }
+
 }
 
 int main(int, const char *[])

From 8c5d06dc791c7dea8148a5d3867473fab2e2fcf3 Mon Sep 17 00:00:00 2001
From: Anna Gringauze <annagrin@microsoft.com>
Date: Mon, 23 Nov 2015 21:24:08 +0000
Subject: [PATCH 35/43] fixed GCC and clang compilation issues

---
 include/string_span.h       | 58 +++++++++++++++++++++----------------
 tests/string_span_tests.cpp |  8 ++++-
 2 files changed, 40 insertions(+), 26 deletions(-)

diff --git a/include/string_span.h b/include/string_span.h
index b11dd9e..b681a5c 100644
--- a/include/string_span.h
+++ b/include/string_span.h
@@ -86,7 +86,7 @@ using wzstring = wchar_t*;
 //
 // Will fail-fast if sentinel cannot be found before max elements are examined.
 //
-template<class T, const T Sentinel>
+template<typename T, const T Sentinel>
 span<T, dynamic_range> ensure_sentinel(T* seq, std::ptrdiff_t max = PTRDIFF_MAX)
 {
     auto cur = seq;
@@ -101,7 +101,7 @@ span<T, dynamic_range> ensure_sentinel(T* seq, std::ptrdiff_t max = PTRDIFF_MAX)
 // Will fail fast if a null-terminator cannot be found before
 // the limit of size_type.
 //
-template<class T>
+template<typename T>
 inline span<T, dynamic_range> ensure_z(T* const & sz, std::ptrdiff_t max = PTRDIFF_MAX)
 {
     return ensure_sentinel<T, 0>(sz, max);
@@ -133,7 +133,7 @@ inline span<const wchar_t, dynamic_range> ensure_z(const wchar_t* const& sz, std
     Ensures(sz[len] == 0); return{ sz, static_cast<std::ptrdiff_t>(len) };
 }
 
-template<class T, size_t N>
+template<typename T, size_t N>
 span<T, dynamic_range> ensure_z(T(&sz)[N]) { return ensure_z(&sz[0], static_cast<std::ptrdiff_t>(N)); }
 
 template<class Cont>
@@ -168,7 +168,7 @@ inline span<const wchar_t, dynamic_range> remove_z(const wchar_t* const& sz, std
     return{ sz, static_cast<std::ptrdiff_t>(len) };
 }
 
-template<class T, size_t N>
+template<typename T, size_t N>
 span<T, dynamic_range> remove_z(T(&sz)[N])
 {
     return remove_z(&sz[0], static_cast<std::ptrdiff_t>(N));
@@ -203,7 +203,7 @@ namespace details
 //
 // Note that Extent is always single-dimension only
 //
-template <class CharT, std::ptrdiff_t Extent = dynamic_range>
+template <typename CharT, std::ptrdiff_t Extent = dynamic_range>
 class basic_string_span
 {
     using value_type = CharT;
@@ -237,7 +237,7 @@ public:
     {}
 
     // from nullptr and length
-    constexpr basic_string_span(nullptr_t ptr, size_type length) noexcept
+    constexpr basic_string_span(std::nullptr_t ptr, size_type length) noexcept
         : real(ptr, length)
     {}
 
@@ -250,8 +250,8 @@ public:
     {}
 
     // from non-const pointer to const span
-    template<typename Dummy = std::enable_if_t<std::is_const<value_type>::value>>
-    constexpr basic_string_span(std::remove_const_t<value_type>*& ptr) noexcept
+    template<typename ValueType = std::remove_const_t<value_type>, bool Enabled = std::is_const<value_type>::value, typename Dummy = std::enable_if_t<Enabled>>
+    constexpr basic_string_span(ValueType*& ptr) noexcept
         : real(ensure_z(ptr))
     {}
 
@@ -306,29 +306,29 @@ public:
     template<size_type Count>
     constexpr basic_string_span<value_type, Count> first() const noexcept
     {
-        return{ real.first<Count>() };
+        return{ real.template first<Count>() };
     }
 
     constexpr basic_string_span<value_type, dynamic_range> first(size_type count) const noexcept
     {
-        return{ real.first(count); }
+        return{ real.first(count) };
     }
 
     template<size_type Count>
     constexpr basic_string_span<value_type, Count> last() const noexcept
     {
-        return{ real.last<Count>() };
+        return{ real.template last<Count>() };
     }
 
     constexpr basic_string_span<value_type, dynamic_range> last(size_type count) const noexcept
     {
-        return{ real.last(count); }
+        return{ real.last(count) };
     }
 
     template<size_type Offset, size_type Count>
     constexpr basic_string_span<value_type, Count> sub() const noexcept
     {
-        return{ real.sub<Count>() };
+        return{ real.template sub<Offset, Count>() };
     }
 
     constexpr basic_string_span<value_type, dynamic_range> sub(size_type offset, size_type count = dynamic_range) const noexcept
@@ -442,7 +442,7 @@ using cwstring_span = basic_string_span<const wchar_t, Extent>;
 //
 #ifndef GSL_MSVC_HAS_TYPE_DEDUCTION_BUG 
 
-template<class CharT, ptrdiff_t Extent>
+template<typename CharT, ptrdiff_t Extent>
 std::basic_string<typename std::remove_const<CharT>::type> to_string(basic_string_span<CharT, Extent> view)
 {
     return{ view.data(), static_cast<size_t>(view.length()) };
@@ -472,7 +472,7 @@ inline std::wstring to_string(wstring_span<> view)
 
 #endif 
 
-template<class CharT, size_t Extent = dynamic_range>
+template<typename CharT, size_t Extent = dynamic_range>
 class basic_zstring_builder
 {
 public:
@@ -509,24 +509,32 @@ template <size_t Max = dynamic_range>
 using wzstring_builder = basic_zstring_builder<wchar_t, Max>;
 }
 
-
-constexpr bool operator==(const gsl::cstring_span<>& one, const gsl::cstring_span<>& other) noexcept
+/*
+bool operator==(const gsl::cstring_span<>& one, const gsl::cstring_span<>& other) noexcept
 {
     return std::equal(one.begin(), one.end(), other.begin(), other.end());
 }
 
-constexpr bool operator==(const gsl::string_span<>& one, const gsl::string_span<>& other) noexcept
+bool operator==(const gsl::cwstring_span<>& one, const gsl::cwstring_span<>& other) noexcept
+{
+    return std::equal(one.begin(), one.end(), other.begin(), other.end());
+}
+*/
+
+
+template <typename CharT>
+bool operator==(const gsl::basic_string_span<CharT, gsl::dynamic_range>& one, const gsl::basic_string_span<CharT, gsl::dynamic_range>& other) noexcept
 {
     return std::equal(one.begin(), one.end(), other.begin(), other.end());
 }
 
-
-// TODO: ca we make twmplate ops work?
-//template <typename ValueType, std::ptrdiff_t Extent>
-//constexpr bool operator==(const gsl::basic_string_span<ValueType, Extent>& one, const gsl::basic_string_span<ValueType, Extent>& other) noexcept
-//{
-//    return std::equal(one.begin(), one.end(), other.begin(), other.end());
-//}
+/*
+template <typename ValueType, std::ptrdiff_t Extent, typename OtherValueType, std::ptrdiff_t OtherExtent, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<ValueType>, std::remove_cv_t<OtherValueType>>::value>>
+constexpr bool operator==(const gsl::basic_string_span<const ValueType, Extent>& one, const gsl::basic_string_span<const OtherValueType, OtherExtent>& other) noexcept
+{
+    return std::equal(one.begin(), one.end(), other.begin(), other.end());
+}
+*/
 /*
 template <typename ValueType, std::ptrdiff_t Extent, typename OtherValueType, std::ptrdiff_t OtherExtent, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<ValueType>, std::remove_cv_t<OtherValueType>>::value>>
 constexpr bool operator==(const gsl::basic_string_span<ValueType, Extent>& one, const gsl::basic_string_span<OtherValueType, OtherExtent>& other) noexcept
diff --git a/tests/string_span_tests.cpp b/tests/string_span_tests.cpp
index 08faaa8..90b7c3c 100644
--- a/tests/string_span_tests.cpp
+++ b/tests/string_span_tests.cpp
@@ -248,7 +248,7 @@ SUITE(string_span_tests)
             cstring_span<> sp2{ ptr, 3 }; // bad... but can't help there
 
             CHECK(sp1[1] == 'b');
-            CHECK_THROW((sp1[2] == 'c'), fail_fast);
+            CHECK_THROW((void)(sp1[2] == 'c'), fail_fast);
 
             CHECK(sp2[1] == 'b');
             //CHECK_THROW((sp1[2] == 'c'), fail_fast); // buffer overflow
@@ -295,9 +295,12 @@ SUITE(string_span_tests)
 
         // from non-const ptr and length
         {
+            // does not compile with GCC (ISO standard does not allow converting string literals to char*)
+#ifdef CONFIRM_COMPILATION_ERRORS
             char* ptr = "Hello";
             cstring_span<> span{ ptr, 5 };
             CHECK(span.length() == 5);
+#endif
         }
 
         // from const string
@@ -398,9 +401,12 @@ SUITE(string_span_tests)
 
         // from non-const ptr and length
         {
+            // does not compile with GCC (ISO standard does not allows converting string literals to char*)
+#ifdef CONFIRM_COMPILATION_ERRORS
             char* ptr = "Hello";
             string_span<> span{ ptr, 5 };
             CHECK(span.length() == 5);
+#endif
         }
 
         // from const string

From 7077105b9de356b67695fe6b5d7ec0af2ec9e107 Mon Sep 17 00:00:00 2001
From: Anna Gringauze <annagrin@microsoft.com>
Date: Mon, 23 Nov 2015 23:05:31 -0800
Subject: [PATCH 36/43] Added operator==

---
 include/string_span.h       | 336 +++++++++++++++++-------------------
 tests/string_span_tests.cpp | 268 +++++++++++++++++++++++-----
 2 files changed, 375 insertions(+), 229 deletions(-)

diff --git a/include/string_span.h b/include/string_span.h
index b681a5c..b6dce6b 100644
--- a/include/string_span.h
+++ b/include/string_span.h
@@ -20,6 +20,7 @@
 #define GSL_STRING_SPAN_H
 
 #include "gsl_assert.h"
+#include "gsl_util.h"
 #include "span.h"
 #include <cstring>
 
@@ -32,12 +33,12 @@
 // VS 2013 workarounds
 #if _MSC_VER <= 1800
 
-#define GSL_MSVC_HAS_TYPE_DEDUCTION_BUG 
+#define GSL_MSVC_HAS_TYPE_DEDUCTION_BUG
 
-// noexcept is not understood 
+// noexcept is not understood
 #ifndef GSL_THROW_ON_CONTRACT_VIOLATION
 #pragma push_macro("noexcept")
-#define noexcept /* nothing */ 
+#define noexcept /* nothing */
 #endif
 
 #endif // _MSC_VER <= 1800
@@ -50,16 +51,16 @@
 #pragma push_macro("noexcept")
 #endif
 
-#define noexcept /* nothing */ 
+#define noexcept /* nothing */
 
-#endif // GSL_THROW_ON_CONTRACT_VIOLATION 
+#endif // GSL_THROW_ON_CONTRACT_VIOLATION
 
 namespace gsl
 {
 //
 // czstring and wzstring
 //
-// These are "tag" typedef's for C-style strings (i.e. null-terminated character arrays) 
+// These are "tag" typedef's for C-style strings (i.e. null-terminated character arrays)
 // that allow static analysis to help find bugs.
 //
 // There are no additional features/semantics that we can find a way to add inside the
@@ -79,7 +80,7 @@ template<std::ptrdiff_t Extent = dynamic_range>
 using wzstring = wchar_t*;
 
 //
-// ensure_sentinel() 
+// ensure_sentinel()
 //
 // Provides a way to obtain an span from a contiguous sequence
 // that ends with a (non-inclusive) sentinel value.
@@ -97,7 +98,7 @@ span<T, dynamic_range> ensure_sentinel(T* seq, std::ptrdiff_t max = PTRDIFF_MAX)
 
 
 //
-// ensure_z - creates a string_span for a czstring or cwzstring.
+// ensure_z - creates a span for a czstring or cwzstring.
 // Will fail fast if a null-terminator cannot be found before
 // the limit of size_type.
 //
@@ -118,19 +119,22 @@ inline span<char, dynamic_range> ensure_z(char* const& sz, std::ptrdiff_t max)
 inline span<const char, dynamic_range> ensure_z(const char* const& sz, std::ptrdiff_t max)
 {
     auto len = strnlen(sz, max);
-    Ensures(sz[len] == 0); return{ sz, static_cast<std::ptrdiff_t>(len) };
+    Ensures(sz[len] == 0);
+    return{ sz, static_cast<std::ptrdiff_t>(len) };
 }
 
 inline span<wchar_t, dynamic_range> ensure_z(wchar_t* const& sz, std::ptrdiff_t max)
 {
     auto len = wcsnlen(sz, max);
-    Ensures(sz[len] == 0); return{ sz, static_cast<std::ptrdiff_t>(len) };
+    Ensures(sz[len] == 0);
+    return{ sz, static_cast<std::ptrdiff_t>(len) };
 }
 
 inline span<const wchar_t, dynamic_range> ensure_z(const wchar_t* const& sz, std::ptrdiff_t max)
 {
     auto len = wcsnlen(sz, max);
-    Ensures(sz[len] == 0); return{ sz, static_cast<std::ptrdiff_t>(len) };
+    Ensures(sz[len] == 0);
+    return{ sz, static_cast<std::ptrdiff_t>(len) };
 }
 
 template<typename T, size_t N>
@@ -142,45 +146,7 @@ span<typename std::remove_pointer<typename Cont::pointer>::type, dynamic_range>
     return ensure_z(cont.data(), static_cast<std::ptrdiff_t>(cont.length()));
 }
 
-
-// TODO (neilmac) there is probably a better template-magic way to get the const and non-const overloads to share an implementation
-inline span<char, dynamic_range> remove_z(char* const& sz, std::ptrdiff_t max)
-{
-    auto len = strnlen(sz, max);
-    return{ sz, static_cast<std::ptrdiff_t>(len) };
-}
-
-inline span<const char, dynamic_range> remove_z(const char* const& sz, std::ptrdiff_t max)
-{
-    auto len = strnlen(sz, max);
-    return{ sz, static_cast<std::ptrdiff_t>(len) };
-}
-
-inline span<wchar_t, dynamic_range> remove_z(wchar_t* const& sz, std::ptrdiff_t max)
-{
-    auto len = wcsnlen(sz, max);
-    return{ sz, static_cast<std::ptrdiff_t>(len) };
-}
-
-inline span<const wchar_t, dynamic_range> remove_z(const wchar_t* const& sz, std::ptrdiff_t max)
-{
-    auto len = wcsnlen(sz, max);
-    return{ sz, static_cast<std::ptrdiff_t>(len) };
-}
-
-template<typename T, size_t N>
-span<T, dynamic_range> remove_z(T(&sz)[N])
-{
-    return remove_z(&sz[0], static_cast<std::ptrdiff_t>(N));
-}
-
-template<class Cont>
-span<typename std::remove_pointer<typename Cont::pointer>::type, dynamic_range> remove_z(Cont& cont)
-{
-    return remove_z(cont.data(), static_cast<std::ptrdiff_t>(cont.length()));
-}
-
-template<typename ValueType, std::ptrdiff_t>
+template<typename CharT, std::ptrdiff_t>
 class basic_string_span;
 
 namespace details
@@ -189,15 +155,56 @@ namespace details
     struct is_basic_string_span_oracle : std::false_type
     {};
 
-    template <typename ValueType, std::ptrdiff_t Extent>
-    struct is_basic_string_span_oracle<basic_string_span<ValueType, Extent>> : std::true_type
+    template <typename CharT, std::ptrdiff_t Extent>
+    struct is_basic_string_span_oracle<basic_string_span<CharT, Extent>> : std::true_type
     {};
 
     template <typename T>
     struct is_basic_string_span : is_basic_string_span_oracle<std::remove_cv_t<T>>
     {};
+
+    template <typename T>
+    struct length_func
+    {};
+
+    template <>
+    struct length_func<char>
+    {
+        std::ptrdiff_t operator()(char* const ptr, std::ptrdiff_t length) noexcept
+        {
+            return narrow_cast<std::ptrdiff_t>(strnlen(ptr, length));
+        }
+    };
+
+    template <>
+    struct length_func<wchar_t>
+    {
+        std::ptrdiff_t operator()(wchar_t* const ptr, std::ptrdiff_t length) noexcept
+        {
+            return narrow_cast<std::ptrdiff_t>(wcsnlen(ptr, length));
+        }
+    };
+
+    template <>
+    struct length_func<const char>
+    {
+        std::ptrdiff_t operator()(const char* const ptr, std::ptrdiff_t length) noexcept
+        {
+            return narrow_cast<std::ptrdiff_t>(strnlen(ptr, length));
+        }
+    };
+
+    template <>
+    struct length_func<const wchar_t>
+    {
+        std::ptrdiff_t operator()(const wchar_t* const ptr, std::ptrdiff_t length) noexcept
+        {
+            return narrow_cast<std::ptrdiff_t>(wcsnlen(ptr, length));
+        }
+    };
 }
 
+
 //
 // string_span and relatives
 //
@@ -212,85 +219,83 @@ class basic_string_span
     using reference = std::add_lvalue_reference_t<value_type>;
     using const_reference = std::add_lvalue_reference_t<const_value_type>;
     using bounds_type = static_bounds<Extent>;
-    using underlying_type = span<value_type, Extent>;
+    using impl_type = span<value_type, Extent>;
 
 public:
     using size_type = ptrdiff_t;
-    using iterator = typename underlying_type::iterator;
-    using const_iterator = typename underlying_type::const_iterator;
-    using reverse_iterator = typename underlying_type::reverse_iterator;
-    using const_reverse_iterator = typename underlying_type::const_reverse_iterator;
+    using iterator = typename impl_type::iterator;
+    using const_iterator = typename impl_type::const_iterator;
+    using reverse_iterator = typename impl_type::reverse_iterator;
+    using const_reverse_iterator = typename impl_type::const_reverse_iterator;
 
-    // empty
-    constexpr basic_string_span() noexcept
-        : real(nullptr)
-    {}
+    // default (empty)
+    constexpr basic_string_span() = default;
 
     // copy
-    constexpr basic_string_span(const basic_string_span& other) noexcept
-        : real(other.real)
-    {}
+    constexpr basic_string_span(const basic_string_span& other) = default;
 
     // move
-    constexpr basic_string_span(const basic_string_span&& other) noexcept
-        : real(std::move(other.real))
-    {}
+    constexpr basic_string_span(basic_string_span&& other) = default;
+
+    // assign
+    constexpr basic_string_span& operator=(const basic_string_span& other) = default;
+
+    // move assign
+    constexpr basic_string_span& operator=(basic_string_span&& other) = default;
 
     // from nullptr and length
     constexpr basic_string_span(std::nullptr_t ptr, size_type length) noexcept
-        : real(ptr, length)
+        : span_(ptr, length)
     {}
 
     // For pointers and static arrays - if 0-terminated, remove 0 from the view
 
-    // from c string
-    
-    constexpr basic_string_span(pointer& ptr) noexcept
-        : real(ensure_z(ptr))
-    {}
-
-    // from non-const pointer to const span
-    template<typename ValueType = std::remove_const_t<value_type>, bool Enabled = std::is_const<value_type>::value, typename Dummy = std::enable_if_t<Enabled>>
-    constexpr basic_string_span(ValueType*& ptr) noexcept
-        : real(ensure_z(ptr))
-    {}
-
-    // from raw data and length - remove 0 if needed
+    // from raw data and length
     constexpr basic_string_span(pointer ptr, size_type length) noexcept
-        : real(remove_z(ptr, length))
+        : span_(remove_z(ptr, length))
     {}
 
     // from static arrays and string literals
     template<size_t N>
     constexpr basic_string_span(value_type(&arr)[N]) noexcept
-        : real(remove_z(arr))
+        : span_(remove_z(arr))
     {}
 
-    // Those allow 0s in the middle, so we keep them
+    // Those allow 0s within the length, so we do not remove them
 
+    // from string
     constexpr basic_string_span(std::string& s) noexcept
-        : real(&(s.at(0)), static_cast<ptrdiff_t>(s.length()))
+        : span_(&(s.at(0)), narrow_cast<std::ptrdiff_t>(s.length()))
     {}
 
-    // from containers. It must have .size() and .data() function signatures
+    // from containers. Containers must have .size() and .data() function signatures
     template <typename Cont, typename DataType = typename Cont::value_type,
         typename Dummy = std::enable_if_t<!details::is_span<Cont>::value
-        && !details::is_basic_string_span<Cont>::value 
+        && !details::is_basic_string_span<Cont>::value
         && !(!std::is_const<value_type>::value && std::is_const<Cont>::value) // no converting const containers to non-const span
         && std::is_convertible<DataType*, value_type*>::value
         && std::is_same<std::decay_t<decltype(std::declval<Cont>().size(), *std::declval<Cont>().data())>, DataType>::value>
     >
     constexpr basic_string_span(Cont& cont)
-        : real(cont.data(), cont.size())
+        : span_(cont.data(), cont.size())
     {}
 
+    // disallow creation from temporary containers and strings
+    template <typename Cont, typename DataType = typename Cont::value_type,
+        typename Dummy = std::enable_if_t<!details::is_span<Cont>::value
+        && !details::is_basic_string_span<Cont>::value
+        && std::is_convertible<DataType*, value_type*>::value
+        && std::is_same<std::decay_t<decltype(std::declval<Cont>().size(), *std::declval<Cont>().data())>, DataType>::value>
+    >
+    basic_string_span(Cont&& cont) = delete;
+
     // from span
     template <typename OtherValueType, std::ptrdiff_t OtherExtent,
         typename OtherBounds = static_bounds<OtherExtent>,
         typename Dummy = std::enable_if_t<std::is_convertible<OtherValueType*, value_type*>::value && std::is_convertible<OtherBounds, bounds_type>::value>
     >
-    constexpr basic_string_span(const span<OtherValueType, OtherExtent>& other) noexcept
-        : real(other)
+    constexpr basic_string_span(span<OtherValueType, OtherExtent> other) noexcept
+        : span_(other)
     {}
 
     // from string_span
@@ -298,131 +303,130 @@ public:
         typename OtherBounds = static_bounds<OtherExtent>,
         typename Dummy = std::enable_if_t<std::is_convertible<OtherValueType*, value_type*>::value && std::is_convertible<OtherBounds, bounds_type>::value>
     >
-    constexpr basic_string_span(const basic_string_span<OtherValueType, OtherExtent>& other) noexcept
-        : real(other.data(), other.length())
+    constexpr basic_string_span(basic_string_span<OtherValueType, OtherExtent> other) noexcept
+        : span_(other.data(), other.length())
     {}
 
-    // section on linear space
+    constexpr bool empty() const noexcept
+    {
+        return length() == 0;
+    }
+
+    // first Count elements
     template<size_type Count>
     constexpr basic_string_span<value_type, Count> first() const noexcept
     {
-        return{ real.template first<Count>() };
+        return{ span_.template first<Count>() };
     }
 
     constexpr basic_string_span<value_type, dynamic_range> first(size_type count) const noexcept
     {
-        return{ real.first(count) };
+        return{ span_.first(count) };
     }
 
+    // last Count elements
     template<size_type Count>
     constexpr basic_string_span<value_type, Count> last() const noexcept
     {
-        return{ real.template last<Count>() };
+        return{ span_.template last<Count>() };
     }
 
     constexpr basic_string_span<value_type, dynamic_range> last(size_type count) const noexcept
     {
-        return{ real.last(count) };
+        return{ span_.last(count) };
     }
 
+    // Count elements starting from Offset
     template<size_type Offset, size_type Count>
     constexpr basic_string_span<value_type, Count> sub() const noexcept
     {
-        return{ real.template sub<Offset, Count>() };
+        return{ span_.template sub<Offset, Count>() };
     }
 
     constexpr basic_string_span<value_type, dynamic_range> sub(size_type offset, size_type count = dynamic_range) const noexcept
     {
-        return{ real.sub(offset, count) };
+        return{ span_.sub(offset, count) };
     }
 
-    constexpr const_reference operator[](size_type idx) const noexcept
+    constexpr reference operator[](size_type idx) const noexcept
     {
-        return real[idx];
-    }
-
-    constexpr reference operator[](size_type idx) noexcept
-    {
-        return real[idx];
+        return span_[idx];
     }
 
     constexpr pointer data() const noexcept
     {
-        return real.data();
+        return span_.data();
     }
 
     constexpr size_type length() const noexcept
     {
-        return real.size();
+        return span_.size();
     }
 
     constexpr size_type size() const noexcept
     {
-        return real.size();
-    }
-
-    constexpr size_type used_length() const noexcept
-    {
-        return length();
+        return span_.size();
     }
 
     constexpr size_type bytes() const noexcept
     {
-        return real.bytes();
-    }
-
-    constexpr size_type used_bytes() const noexcept
-    {
-        return bytes();
-    }
-
-    constexpr explicit operator bool() const noexcept
-    {
-        return real;
+        return span_.bytes();
     }
 
     constexpr iterator begin() const noexcept
     {
-        return real.begin();
+        return span_.begin();
     }
 
     constexpr iterator end() const noexcept
     {
-        return real.end();
+        return span_.end();
     }
 
     constexpr const_iterator cbegin() const noexcept
     {
-        return real.cbegin();
+        return span_.cbegin();
     }
 
     constexpr const_iterator cend() const noexcept
     {
-        real.cend();
+        span_.cend();
     }
 
     constexpr reverse_iterator rbegin() const noexcept
     {
-        return real.rbegin();
+        return span_.rbegin();
     }
 
     constexpr reverse_iterator rend() const noexcept
     {
-        return real.rend();
+        return span_.rend();
     }
 
     constexpr const_reverse_iterator crbegin() const noexcept
     {
-        return real.crbegin();
+        return span_.crbegin();
     }
 
     constexpr const_reverse_iterator crend() const noexcept
     {
-        return real.crend();
+        return span_.crend();
     }
 
 private:
-    span<CharT, Extent> real;
+
+    static impl_type remove_z(pointer const& sz, std::ptrdiff_t max) noexcept
+    {
+        return{ sz, details::length_func<value_type>()(sz, max)};
+    }
+
+    template<size_t N>
+    static impl_type remove_z(value_type(&sz)[N]) noexcept
+    {
+        return remove_z(&sz[0], narrow_cast<std::ptrdiff_t>(N));
+    }
+
+    impl_type span_;
 };
 
 template<std::ptrdiff_t Extent = dynamic_range>
@@ -440,7 +444,7 @@ using cwstring_span = basic_string_span<const wchar_t, Extent>;
 //
 // to_string() allow (explicit) conversions from string_span to string
 //
-#ifndef GSL_MSVC_HAS_TYPE_DEDUCTION_BUG 
+#ifndef GSL_MSVC_HAS_TYPE_DEDUCTION_BUG
 
 template<typename CharT, ptrdiff_t Extent>
 std::basic_string<typename std::remove_const<CharT>::type> to_string(basic_string_span<CharT, Extent> view)
@@ -470,12 +474,13 @@ inline std::wstring to_string(wstring_span<> view)
     return{ view.data(), view.length() };
 }
 
-#endif 
+#endif
 
 template<typename CharT, size_t Extent = dynamic_range>
 class basic_zstring_builder
 {
 public:
+    using impl_type = span<CharT, Extent>;
     using string_span_type = basic_string_span<CharT, Extent>;
     using value_type = CharT;
     using pointer = CharT*;
@@ -499,7 +504,7 @@ public:
     iterator end() const { return sv_.end(); }
 
 private:
-    string_span_type sv_;
+    impl_type sv_;
 };
 
 template <size_t Max = dynamic_range>
@@ -509,69 +514,36 @@ template <size_t Max = dynamic_range>
 using wzstring_builder = basic_zstring_builder<wchar_t, Max>;
 }
 
-/*
-bool operator==(const gsl::cstring_span<>& one, const gsl::cstring_span<>& other) noexcept
+template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range>
+bool operator==(const gsl::basic_string_span<CharT, Extent>& one, const gsl::basic_string_span<CharT, Extent>& other) noexcept
 {
     return std::equal(one.begin(), one.end(), other.begin(), other.end());
 }
 
-bool operator==(const gsl::cwstring_span<>& one, const gsl::cwstring_span<>& other) noexcept
-{
-    return std::equal(one.begin(), one.end(), other.begin(), other.end());
-}
-*/
-
-
-template <typename CharT>
-bool operator==(const gsl::basic_string_span<CharT, gsl::dynamic_range>& one, const gsl::basic_string_span<CharT, gsl::dynamic_range>& other) noexcept
-{
-    return std::equal(one.begin(), one.end(), other.begin(), other.end());
-}
-
-/*
-template <typename ValueType, std::ptrdiff_t Extent, typename OtherValueType, std::ptrdiff_t OtherExtent, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<ValueType>, std::remove_cv_t<OtherValueType>>::value>>
-constexpr bool operator==(const gsl::basic_string_span<const ValueType, Extent>& one, const gsl::basic_string_span<const OtherValueType, OtherExtent>& other) noexcept
-{
-    return std::equal(one.begin(), one.end(), other.begin(), other.end());
-}
-*/
-/*
-template <typename ValueType, std::ptrdiff_t Extent, typename OtherValueType, std::ptrdiff_t OtherExtent, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<ValueType>, std::remove_cv_t<OtherValueType>>::value>>
-constexpr bool operator==(const gsl::basic_string_span<ValueType, Extent>& one, const gsl::basic_string_span<OtherValueType, OtherExtent>& other) noexcept
-{
-    return std::equal(one.begin(), one.end(), other.begin(), other.end());
-}
-
-template <typename ValueType, std::ptrdiff_t Extent, typename OtherValueType, std::ptrdiff_t OtherExtent, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<ValueType>, std::remove_cv_t<OtherValueType>>::value>>
-constexpr bool operator!=(const gsl::basic_string_span<ValueType, Extent>& one, const gsl::basic_string_span<OtherValueType, OtherExtent>& other) noexcept
-{
-    return !(one == other);
-}
-
-template <typename ValueType, std::ptrdiff_t Extent, typename OtherValueType, std::ptrdiff_t OtherExtent, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<ValueType>, std::remove_cv_t<OtherValueType>>::value>>
-constexpr bool operator<(const gsl::basic_string_span<ValueType, Extent>& one, const gsl::basic_string_span<OtherValueType, OtherExtent>& other) noexcept
+template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range>
+bool operator<(const gsl::basic_string_span<CharT, Extent>& one, const gsl::basic_string_span<CharT, Extent>& other) noexcept
 {
     return std::lexicographical_compare(one.begin(), one.end(), other.begin(), other.end());
 }
 
-template <typename ValueType, std::ptrdiff_t Extent, typename OtherValueType, std::ptrdiff_t OtherExtent, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<ValueType>, std::remove_cv_t<OtherValueType>>::value>>
-constexpr bool operator<=(const gsl::basic_string_span<ValueType, Extent>& one, const gsl::basic_string_span<OtherValueType, OtherExtent>& other) noexcept
+template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range>
+bool operator<=(const gsl::basic_string_span<CharT, Extent>& one, const gsl::basic_string_span<CharT, Extent>& other) noexcept
 {
     return !(other < one);
 }
 
-template <typename ValueType, std::ptrdiff_t Extent, typename OtherValueType, std::ptrdiff_t OtherExtent, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<ValueType>, std::remove_cv_t<OtherValueType>>::value>>
-constexpr bool operator>(const gsl::basic_string_span<ValueType, Extent>& one, const gsl::basic_string_span<OtherValueType, OtherExtent>& other) noexcept
+template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range>
+bool operator>(const gsl::basic_string_span<CharT, Extent>& one, const gsl::basic_string_span<CharT, Extent>& other) noexcept
 {
     return other < one;
 }
 
-template <typename ValueType, std::ptrdiff_t Extent, typename OtherValueType, std::ptrdiff_t OtherExtent, typename Dummy = std::enable_if_t<std::is_same<std::remove_cv_t<ValueType>, std::remove_cv_t<OtherValueType>>::value>>
-constexpr bool operator>=(const gsl::basic_string_span<ValueType, Extent>& one, const gsl::basic_string_span<OtherValueType, OtherExtent>& other) noexcept
+template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range>
+bool operator>=(const gsl::basic_string_span<CharT, Extent>& one, const gsl::basic_string_span<CharT, Extent>& other) noexcept
 {
     return !(one < other);
 }
-*/
+
 // VS 2013 workarounds
 #ifdef _MSC_VER
 
@@ -592,7 +564,7 @@ constexpr bool operator>=(const gsl::basic_string_span<ValueType, Extent>& one,
 #endif // _MSC_VER <= 1800
 #endif // _MSC_VER
 
-#if defined(GSL_THROW_ON_CONTRACT_VIOLATION) 
+#if defined(GSL_THROW_ON_CONTRACT_VIOLATION)
 
 #undef noexcept
 
diff --git a/tests/string_span_tests.cpp b/tests/string_span_tests.cpp
index 90b7c3c..4e42cc5 100644
--- a/tests/string_span_tests.cpp
+++ b/tests/string_span_tests.cpp
@@ -14,12 +14,10 @@
 // 
 ///////////////////////////////////////////////////////////////////////////////
 
-#include <UnitTest++/UnitTest++.h> 
+#include <UnitTest++/UnitTest++.h>
 #include <string_span.h>
 #include <vector>
 #include <cstdlib>
-#include <map>
-#include <unordered_map>
 
 using namespace std;
 using namespace gsl;
@@ -76,7 +74,7 @@ SUITE(string_span_tests)
             wstring_span<> v = stack_string;
             CHECK(v.length() == 5);
         }
-	}
+    }
 
     TEST(TestConstructFromConstCharPointer)
     {
@@ -89,7 +87,7 @@ SUITE(string_span_tests)
     {
         char stack_string[] = "Hello";
         string_span<> v = ensure_z(stack_string);
-        cstring_span<> v2 = v; 
+        cstring_span<> v2 = v;
         CHECK(v.length() == v2.length());
     }
 
@@ -116,7 +114,7 @@ SUITE(string_span_tests)
         CHECK(s2.length() == 5);
     }
 
-    TEST(ComparisonAndImplicitConstructors)
+    TEST(EqualityAndImplicitConstructors)
     {
         {
             cstring_span<> span = "Hello";
@@ -132,25 +130,60 @@ SUITE(string_span_tests)
             CHECK(span == cstring_span<>("Hello"));
 
             // comparison to static array with no null termination
-            CHECK(span == cstring_span<>(ar)); 
+            CHECK(span == cstring_span<>(ar));
 
             // comparison to static array with null at the end
             CHECK(span == cstring_span<>(ar1));
 
             // comparison to static array with null in the middle
-            CHECK(span == cstring_span<>(ar2)); 
+            CHECK(span == cstring_span<>(ar2));
 
             // comparison to null-terminated c string
-            CHECK(span == cstring_span<>(ptr, 5)); 
+            CHECK(span == cstring_span<>(ptr, 5));
 
             // comparison to string
-            CHECK(span == cstring_span<>(str)); 
+            CHECK(span == cstring_span<>(str));
 
             // comparison to vector of charaters with no null termination
-            CHECK(span == cstring_span<>(vec)); 
+            CHECK(span == cstring_span<>(vec));
 
             // comparison of the original data to string
             CHECK(span.data() == std::string("Hello"));
+        }
+
+        {
+            char ar[] = { 'H', 'e', 'l', 'l', 'o' };
+
+            string_span<> span = ar;
+
+            char ar1[] = "Hello";
+            char ar2[10] = "Hello";
+            char* ptr = ar;
+            std::string str = "Hello";
+            std::vector<char> vec = { 'H', 'e', 'l', 'l', 'o' };
+
+            // comparison to static array with no null termination
+            CHECK(span == string_span<>(ar));
+
+            // comparison to static array with null at the end
+            CHECK(span == string_span<>(ar1));
+
+            // comparison to static array with null in the middle
+            CHECK(span == string_span<>(ar2));
+
+            // comparison to null-terminated c string
+            CHECK(span == string_span<>(ptr, 5));
+
+            // comparison to string
+            CHECK(span == string_span<>(str));
+
+            // comparison to vector of charaters with no null termination
+            CHECK(span == string_span<>(vec));
+        }
+
+#ifdef CONFIRM_COMPILATION_ERRORS
+        {
+            cstring_span<> span = "Hello";
 
             CHECK(span == "Hello");
             CHECK(span == ar);
@@ -159,7 +192,7 @@ SUITE(string_span_tests)
             CHECK(span == ptr);
             CHECK(span == str);
             CHECK(span == vec);
-            
+
             char _ar[] = { 'H', 'e', 'l', 'l', 'o' };
             char _ar1[] = "Hello";
             char _ar2[10] = "Hello";
@@ -191,6 +224,7 @@ SUITE(string_span_tests)
             CHECK(_span == str);
             CHECK(_span == vec);
         }
+#endif
 
         {
             std::vector<char> str1 = { 'H', 'e', 'l', 'l', 'o' };
@@ -203,6 +237,78 @@ SUITE(string_span_tests)
         }
     }
 
+
+    TEST(ComparisonAndImplicitConstructors)
+    {
+        {
+            cstring_span<> span = "Hello";
+
+            const char ar[] = { 'H', 'e', 'l', 'l', 'o' };
+            const char ar1[] = "Hello";
+            const char ar2[10] = "Hello";
+            const char* ptr = "Hello";
+            const std::string str = "Hello";
+            const std::vector<char> vec = { 'H', 'e', 'l', 'l', 'o' };
+
+            // comparison to  literal
+            CHECK(span < cstring_span<>("Helloo"));
+            CHECK(span > cstring_span<>("Hell"));
+
+            // comparison to static array with no null termination
+            CHECK(span >= cstring_span<>(ar));
+
+            // comparison to static array with null at the end
+            CHECK(span <= cstring_span<>(ar1));
+
+            // comparison to static array with null in the middle
+            CHECK(span >= cstring_span<>(ar2));
+
+            // comparison to null-terminated c string
+            CHECK(span <= cstring_span<>(ptr, 5));
+
+            // comparison to string
+            CHECK(span >= cstring_span<>(str));
+
+            // comparison to vector of charaters with no null termination
+            CHECK(span <= cstring_span<>(vec));
+        }
+
+        {
+            char ar[] = { 'H', 'e', 'l', 'l', 'o' };
+
+            string_span<> span = ar;
+
+            char larr[] = "Hell";
+            char rarr[] = "Helloo";
+
+            char ar1[] = "Hello";
+            char ar2[10] = "Hello";
+            char* ptr = ar;
+            std::string str = "Hello";
+            std::vector<char> vec = { 'H', 'e', 'l', 'l', 'o' };
+
+
+            // comparison to static array with no null termination
+            CHECK(span <= string_span<>(ar));
+            CHECK(span < string_span<>(rarr));
+            CHECK(span > string_span<>(larr));
+
+            // comparison to static array with null at the end
+            CHECK(span >= string_span<>(ar1));
+
+            // comparison to static array with null in the middle
+            CHECK(span <= string_span<>(ar2));
+
+            // comparison to null-terminated c string
+            CHECK(span >= string_span<>(ptr, 5));
+
+            // comparison to string
+            CHECK(span <= string_span<>(str));
+
+            // comparison to vector of charaters with no null termination
+            CHECK(span >= string_span<>(vec));
+        }
+    }
     TEST(EnzureRemoveZ)
     {
         // remove z from literals
@@ -226,39 +332,17 @@ SUITE(string_span_tests)
             ptr[1] = 'b';
             ptr[2] = '\0';
 
-            string_span<> span(ptr);
+            string_span<> span = ensure_z(ptr);
             CHECK(span.length() == 2);
 
             delete[] ptr;
         }
-
-        // ensuze z on c strings
-        {
-            char* ptr = new char[2];
-
-            ptr[0] = 'a';
-            ptr[1] = 'b';
-
-            // do we want to have a constructor from pointer at all?
-            // the behavior is unpredictable if the string is not 0-terminated
-
-            // CHECK_THROW((string_span<>(ptr).length() == 2), fail_fast);
-
-            cstring_span<> sp1{ ptr, 2 }; // good
-            cstring_span<> sp2{ ptr, 3 }; // bad... but can't help there
-
-            CHECK(sp1[1] == 'b');
-            CHECK_THROW((void)(sp1[2] == 'c'), fail_fast);
-
-            CHECK(sp2[1] == 'b');
-            //CHECK_THROW((sp1[2] == 'c'), fail_fast); // buffer overflow
-
-            delete[] ptr;
-        }
     }
 
     TEST(Constructors)
     {
+        // creating cstring_span
+
         // from string temporary
 #ifdef CONFIRM_COMPILATION_ERRORS
         {
@@ -363,14 +447,12 @@ SUITE(string_span_tests)
             CHECK(span.length() == 5);
         }
 
-        ///////////////////////////////////////////////////
-        // How string_span should behave with const data
+        // creating string_span
 
         // from string literal
         {
 #ifdef CONFIRM_COMPILATION_ERRORS
             string_span<> span = "Hello";
-            CHECK(span.length() == 5);
 #endif
         }
 
@@ -401,12 +483,10 @@ SUITE(string_span_tests)
 
         // from non-const ptr and length
         {
-            // does not compile with GCC (ISO standard does not allows converting string literals to char*)
-#ifdef CONFIRM_COMPILATION_ERRORS
-            char* ptr = "Hello";
+            char ar[] = { 'H', 'e', 'l', 'l', 'o' };
+            char* ptr = ar;
             string_span<> span{ ptr, 5 };
             CHECK(span.length() == 5);
-#endif
         }
 
         // from const string
@@ -459,11 +539,11 @@ SUITE(string_span_tests)
             CHECK(span.length() == 5);
         }
 
-        // from non-const span of non-const data from const vector (looks like a bug)
+        // from non-const span of non-const data from const vector
         {
 #ifdef CONFIRM_COMPILATION_ERRORS
             const std::vector<char> vec = { 'H', 'e', 'l', 'l', 'o' };
-            const span<char> inner = vec; // fix error (happens inside the constructor)
+            const span<char> inner = vec;
             string_span<> span = inner;
             CHECK(span.length() == 5);
 #endif
@@ -500,12 +580,106 @@ SUITE(string_span_tests)
         // from const string_span of non-const data
         {
             std::vector<char> vec = { 'H', 'e', 'l', 'l', 'o' };
-            const string_span<> tmp = vec; // what does "const span" mean?
+            const string_span<> tmp = vec;
             string_span<> span = tmp;
             CHECK(span.length() == 5);
         }
     }
 
+    template<typename T>
+    T move_wrapper(T&& t)
+    {
+        return std::move(t);
+    }
+
+    template <class T>
+    T create() { return T{}; }
+
+    template <class T>
+    void use(basic_string_span<T, gsl::dynamic_range> s) {}
+
+    TEST(MoveConstructors)
+    {
+        // move string_span
+        {
+            cstring_span<> span = "Hello";
+            auto span1 = std::move(span);
+            CHECK(span1.length() == 5);
+        }
+        {
+            cstring_span<> span = "Hello";
+            auto span1 = move_wrapper(std::move(span));
+            CHECK(span1.length() == 5);
+        }
+        {
+            cstring_span<> span = "Hello";
+            auto span1 = move_wrapper(std::move(span));
+            CHECK(span1.length() == 5);
+        }
+
+        // move span
+        {
+            span<const char> span = ensure_z("Hello");
+            cstring_span<> span1 = std::move(span);
+            CHECK(span1.length() == 5);
+        }
+        {
+            span<const char> span = ensure_z("Hello");
+            cstring_span<> span2 = move_wrapper(std::move(span));
+            CHECK(span2.length() == 5);
+        }
+
+        // move string
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            std::string str = "Hello";
+            string_span<> span = std::move(str);
+            CHECK(span.length() == 5);
+#endif
+        }
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            std::string str = "Hello";
+            string_span<> span = move_wrapper<std::string>(std::move(str));
+            CHECK(span.length() == 5);
+#endif
+        }
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            use<char>(create<string>());
+#endif
+        }
+
+        // move container
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            std::vector<char> vec = { 'H', 'e', 'l', 'l', 'o' };
+            string_span<> span = std::move(vec);
+            CHECK(span.length() == 5);
+#endif
+        }
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            std::vector<char> vec = { 'H', 'e', 'l', 'l', 'o' };
+            string_span<> span = move_wrapper<std::vector<char>>(std::move(vec));
+            CHECK(span.length() == 5);
+#endif
+        }
+        {
+#ifdef CONFIRM_COMPILATION_ERRORS
+            use<char>(create<std::vector<char>>());
+#endif
+        }
+    }
+
+    TEST(Conversion)
+    {
+#ifdef CONFIRM_COMPPILATION_ERRORS
+        cstring_span<> span = "Hello";
+        cwstring_span<> wspan{ span };
+        CHECK(wspan.length() == 5);
+#endif
+    }
 }
 
 int main(int, const char *[])

From de6dbacbf6debb96297f4c554473069b8a3edb4c Mon Sep 17 00:00:00 2001
From: Anna Gringauze <annagrin@microsoft.com>
Date: Tue, 1 Dec 2015 13:52:01 -0800
Subject: [PATCH 37/43] Addressed CR comments

---
 include/string_span.h | 23 ++++++++++++++++-------
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/include/string_span.h b/include/string_span.h
index b6dce6b..cc87068 100644
--- a/include/string_span.h
+++ b/include/string_span.h
@@ -336,16 +336,16 @@ public:
         return{ span_.last(count) };
     }
 
-    // Count elements starting from Offset
+    // create a subview of Count elements starting from Offset
     template<size_type Offset, size_type Count>
-    constexpr basic_string_span<value_type, Count> sub() const noexcept
+    constexpr basic_string_span<value_type, Count> subspan() const noexcept
     {
-        return{ span_.template sub<Offset, Count>() };
+        return{ span_.template subspan<Offset, Count>() };
     }
 
-    constexpr basic_string_span<value_type, dynamic_range> sub(size_type offset, size_type count = dynamic_range) const noexcept
+    constexpr basic_string_span<value_type, dynamic_range> subspan(size_type offset, size_type count = dynamic_range) const noexcept
     {
-        return{ span_.sub(offset, count) };
+        return{ span_.subspan(offset, count) };
     }
 
     constexpr reference operator[](size_type idx) const noexcept
@@ -358,19 +358,28 @@ public:
         return span_.data();
     }
 
+    // length of the span in elements
     constexpr size_type length() const noexcept
     {
         return span_.size();
     }
 
+    // length of the span in elements
     constexpr size_type size() const noexcept
     {
         return span_.size();
     }
 
-    constexpr size_type bytes() const noexcept
+    // length of the span in bytes
+    constexpr size_type size_bytes() const noexcept
     {
-        return span_.bytes();
+        return span_.size_bytes();
+    }
+
+    // length of the span in bytes
+    constexpr size_type length_bytes() const noexcept
+    {
+        return span_.length_bytes();
     }
 
     constexpr iterator begin() const noexcept

From 4efa9e8f07fbe5799444c8464bd6061403dce9ef Mon Sep 17 00:00:00 2001
From: Anna Gringauze <annagrin@microsoft.com>
Date: Wed, 2 Dec 2015 12:28:43 -0800
Subject: [PATCH 38/43] Run clang format

---
 tests/string_span_tests.cpp | 29 +++++++++++++++--------------
 1 file changed, 15 insertions(+), 14 deletions(-)

diff --git a/tests/string_span_tests.cpp b/tests/string_span_tests.cpp
index 4e42cc5..a966955 100644
--- a/tests/string_span_tests.cpp
+++ b/tests/string_span_tests.cpp
@@ -1,18 +1,19 @@
-/////////////////////////////////////////////////////////////////////////////// 
-// 
-// Copyright (c) 2015 Microsoft Corporation. All rights reserved. 
-// 
-// This code is licensed under the MIT License (MIT). 
-// 
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 
-// THE SOFTWARE. 
-// 
 ///////////////////////////////////////////////////////////////////////////////
+//
+// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
+//
+// This code is licensed under the MIT License (MIT).
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+//
+///////////////////////////////////////////////////////////////////////////////
+
 
 #include <UnitTest++/UnitTest++.h>
 #include <string_span.h>

From eedd18d5b8208a096bff2790a161ebb5f863defd Mon Sep 17 00:00:00 2001
From: mcheese <mcheese@users.noreply.github.com>
Date: Sun, 6 Dec 2015 13:43:03 +0100
Subject: [PATCH 39/43] Correct missing rename of bytes() to size_bytes()

---
 include/span.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/span.h b/include/span.h
index 8151737..72d55d6 100644
--- a/include/span.h
+++ b/include/span.h
@@ -1669,7 +1669,7 @@ constexpr auto as_span(span<byte, Dimensions...> s) noexcept -> span<
              ByteSpan::bounds_type::static_size % static_cast<std::size_t>(sizeof(U)) == 0),
         "Target type must be a trivial type and its size must match the byte array size");
 
-    Expects((s.bytes() % sizeof(U)) == 0);
+    Expects((s.size_bytes() % sizeof(U)) == 0);
     return {reinterpret_cast<U*>(s.data()),
             s.size_bytes() / narrow_cast<std::ptrdiff_t>(sizeof(U))};
 }

From 87c5daa6c4c00d7660e5343d8d1dd13e300390a5 Mon Sep 17 00:00:00 2001
From: Anna Gringauze <annagrin@microsoft.com>
Date: Fri, 4 Dec 2015 14:23:13 -0800
Subject: [PATCH 40/43] Fixed operators and constructors for string_span

---
 include/string_span.h       | 161 +++++++++++++++++++++++++++++-------
 tests/string_span_tests.cpp | 145 +++++++++++++++++++++++++++++---
 2 files changed, 262 insertions(+), 44 deletions(-)

diff --git a/include/string_span.h b/include/string_span.h
index cc87068..8418029 100644
--- a/include/string_span.h
+++ b/include/string_span.h
@@ -1,17 +1,17 @@
-/////////////////////////////////////////////////////////////////////////////// 
-// 
-// Copyright (c) 2015 Microsoft Corporation. All rights reserved. 
-// 
-// This code is licensed under the MIT License (MIT). 
-// 
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 
-// THE SOFTWARE. 
-// 
+///////////////////////////////////////////////////////////////////////////////
+//
+// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
+//
+// This code is licensed under the MIT License (MIT).
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+//
 ///////////////////////////////////////////////////////////////////////////////
 
 #pragma once
@@ -243,17 +243,17 @@ public:
     // move assign
     constexpr basic_string_span& operator=(basic_string_span&& other) = default;
 
+    // from nullptr
+    constexpr basic_string_span(std::nullptr_t ptr) noexcept
+        : span_(ptr)
+    {}
+
     // from nullptr and length
     constexpr basic_string_span(std::nullptr_t ptr, size_type length) noexcept
         : span_(ptr, length)
     {}
 
-    // For pointers and static arrays - if 0-terminated, remove 0 from the view
-
-    // from raw data and length
-    constexpr basic_string_span(pointer ptr, size_type length) noexcept
-        : span_(remove_z(ptr, length))
-    {}
+    // From static arrays - if 0-terminated, remove 0 from the view
 
     // from static arrays and string literals
     template<size_t N>
@@ -263,6 +263,11 @@ public:
 
     // Those allow 0s within the length, so we do not remove them
 
+    // from raw data and length
+    constexpr basic_string_span(pointer ptr, size_type length) noexcept
+        : span_(ptr, length)
+    {}
+
     // from string
     constexpr basic_string_span(std::string& s) noexcept
         : span_(&(s.at(0)), narrow_cast<std::ptrdiff_t>(s.length()))
@@ -523,32 +528,126 @@ template <size_t Max = dynamic_range>
 using wzstring_builder = basic_zstring_builder<wchar_t, Max>;
 }
 
-template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range>
-bool operator==(const gsl::basic_string_span<CharT, Extent>& one, const gsl::basic_string_span<CharT, Extent>& other) noexcept
+// operator ==
+template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
+    typename = std::enable_if_t<
+    std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value>
+>
+bool operator==(gsl::basic_string_span<CharT, Extent> one, const T& other) noexcept
 {
-    return std::equal(one.begin(), one.end(), other.begin(), other.end());
+    gsl::basic_string_span<std::add_const_t<CharT>, Extent> tmp(other);
+    return std::equal(one.begin(), one.end(), tmp.begin(), tmp.end());
 }
 
-template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range>
-bool operator<(const gsl::basic_string_span<CharT, Extent>& one, const gsl::basic_string_span<CharT, Extent>& other) noexcept
+template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
+    typename Dummy = std::enable_if_t<
+    std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value
+    && !details::is_basic_string_span<T>::value>
+>
+bool operator==(const T& one, gsl::basic_string_span<CharT, Extent> other) noexcept
 {
+    gsl::basic_string_span<std::add_const_t<CharT>, Extent> tmp(one);
+    return std::equal(tmp.begin(), tmp.end(), other.begin(), other.end());
+}
+
+// operator !=
+template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
+    typename = std::enable_if_t<
+    std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value>
+>
+bool operator!=(gsl::basic_string_span<CharT, Extent> one, const T& other) noexcept
+{
+    return !(one == other);
+}
+
+template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
+    typename Dummy = std::enable_if_t<
+    std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value
+    && !details::is_basic_string_span<T>::value>
+>
+bool operator!=(const T& one, gsl::basic_string_span<CharT, Extent> other) noexcept
+{
+    return !(one == other);
+}
+
+// operator<
+template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
+    typename = std::enable_if_t<
+    std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value>
+>
+bool operator<(gsl::basic_string_span<CharT, Extent> one, const T& other) noexcept
+{
+    gsl::basic_string_span<std::add_const_t<CharT>, Extent> tmp(other);
     return std::lexicographical_compare(one.begin(), one.end(), other.begin(), other.end());
 }
 
-template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range>
-bool operator<=(const gsl::basic_string_span<CharT, Extent>& one, const gsl::basic_string_span<CharT, Extent>& other) noexcept
+template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
+    typename Dummy = std::enable_if_t<
+    std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value
+    && !details::is_basic_string_span<T>::value>
+>
+bool operator<(const T& one, gsl::basic_string_span<CharT, Extent> other) noexcept
+{
+    gsl::basic_string_span<std::add_const_t<CharT>, Extent> tmp(one);
+    return std::lexicographical_compare(tmp.begin(), tmp.end(), other.begin(), other.end());
+}
+
+// operator <=
+template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
+    typename = std::enable_if_t<
+    std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value>
+>
+bool operator<=(gsl::basic_string_span<CharT, Extent> one, const T& other) noexcept
 {
     return !(other < one);
 }
 
-template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range>
-bool operator>(const gsl::basic_string_span<CharT, Extent>& one, const gsl::basic_string_span<CharT, Extent>& other) noexcept
+template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
+    typename Dummy = std::enable_if_t<
+    std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value
+    && !details::is_basic_string_span<T>::value>
+>
+bool operator<=(const T& one, gsl::basic_string_span<CharT, Extent> other) noexcept
+{
+    return !(other < one);
+}
+
+// operator>
+template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
+    typename = std::enable_if_t<
+    std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value>
+>
+bool operator>(gsl::basic_string_span<CharT, Extent> one, const T& other) noexcept
 {
     return other < one;
 }
 
-template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range>
-bool operator>=(const gsl::basic_string_span<CharT, Extent>& one, const gsl::basic_string_span<CharT, Extent>& other) noexcept
+template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
+    typename Dummy = std::enable_if_t<
+    std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value
+    && !details::is_basic_string_span<T>::value>
+>
+bool operator>(const T& one, gsl::basic_string_span<CharT, Extent> other) noexcept
+{
+    return other < one;
+}
+
+// operator >=
+template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
+    typename = std::enable_if_t<
+    std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value>
+>
+bool operator>=(gsl::basic_string_span<CharT, Extent> one, const T& other) noexcept
+{
+    return !(one < other);
+}
+
+template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
+    typename Dummy = std::enable_if_t<
+    std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value
+    && !details::is_basic_string_span<T>::value>
+>
+bool operator>=(const T& one, gsl::basic_string_span<CharT, Extent> other) noexcept
 {
     return !(one < other);
 }
diff --git a/tests/string_span_tests.cpp b/tests/string_span_tests.cpp
index a966955..18fda26 100644
--- a/tests/string_span_tests.cpp
+++ b/tests/string_span_tests.cpp
@@ -14,11 +14,10 @@
 //
 ///////////////////////////////////////////////////////////////////////////////
 
-
 #include <UnitTest++/UnitTest++.h>
+#include <cstdlib>
 #include <string_span.h>
 #include <vector>
-#include <cstdlib>
 
 using namespace std;
 using namespace gsl;
@@ -126,6 +125,7 @@ SUITE(string_span_tests)
             const char* ptr = "Hello";
             const std::string str = "Hello";
             const std::vector<char> vec = { 'H', 'e', 'l', 'l', 'o' };
+            gsl::span<const char> sp = ensure_z("Hello");
 
             // comparison to  literal
             CHECK(span == cstring_span<>("Hello"));
@@ -148,6 +148,12 @@ SUITE(string_span_tests)
             // comparison to vector of charaters with no null termination
             CHECK(span == cstring_span<>(vec));
 
+            // comparison to span
+            CHECK(span == cstring_span<>(sp));
+
+            // comparison to string_span
+            CHECK(span == span);
+
             // comparison of the original data to string
             CHECK(span.data() == std::string("Hello"));
         }
@@ -162,6 +168,7 @@ SUITE(string_span_tests)
             char* ptr = ar;
             std::string str = "Hello";
             std::vector<char> vec = { 'H', 'e', 'l', 'l', 'o' };
+            gsl::span<char> sp = ensure_z(ar1);
 
             // comparison to static array with no null termination
             CHECK(span == string_span<>(ar));
@@ -180,52 +187,133 @@ SUITE(string_span_tests)
 
             // comparison to vector of charaters with no null termination
             CHECK(span == string_span<>(vec));
+
+            // comparison to span
+            CHECK(span == string_span<>(sp));
+
+            // comparison to string_span
+            CHECK(span == span);
         }
 
-#ifdef CONFIRM_COMPILATION_ERRORS
+
         {
+            const char ar[] = { 'H', 'e', 'l', 'l', 'o' };
+            const char ar1[] = "Hello";
+            const char ar2[10] = "Hello";
+            const std::string str = "Hello";
+            const std::vector<char> vec = { 'H', 'e', 'l', 'l', 'o' };
+            gsl::span<const char> sp = ensure_z("Hello");
+
             cstring_span<> span = "Hello";
 
+            // const span, const other type
+
             CHECK(span == "Hello");
             CHECK(span == ar);
             CHECK(span == ar1);
             CHECK(span == ar2);
+#ifdef CONFIRM_COMPILATION_ERRORS
+            const char* ptr = "Hello";
             CHECK(span == ptr);
+#endif
             CHECK(span == str);
             CHECK(span == vec);
+            CHECK(span == sp);
+
+            CHECK("Hello" == span);
+            CHECK(ar == span);
+            CHECK(ar1 == span);
+            CHECK(ar2 == span);
+#ifdef CONFIRM_COMPILATION_ERRORS
+            CHECK(ptr == span);
+#endif
+            CHECK(str == span);
+            CHECK(vec == span);
+            CHECK(sp == span);
+
+            // const span, non-const other type
 
             char _ar[] = { 'H', 'e', 'l', 'l', 'o' };
             char _ar1[] = "Hello";
             char _ar2[10] = "Hello";
-            char* _ptr = _ar1;
+            char* _ptr = _ar;
             std::string _str = "Hello";
             std::vector<char> _vec = { 'H', 'e', 'l', 'l', 'o' };
+            gsl::span<char> _sp{ _ar, 5 };
 
             CHECK(span == _ar);
             CHECK(span == _ar1);
             CHECK(span == _ar2);
+#ifdef CONFIRM_COMPILATION_ERRORS
             CHECK(span == _ptr);
+#endif
             CHECK(span == _str);
             CHECK(span == _vec);
+            CHECK(span == _sp);
 
-            string_span<> _span{ _ptr };
+            CHECK(_ar == span);
+            CHECK(_ar1 == span);
+            CHECK(_ar2 == span);
+#ifdef CONFIRM_COMPILATION_ERRORS
+            CHECK(_ptr == span);
+#endif
+            CHECK(_str == span);
+            CHECK(_vec == span);
+            CHECK(_sp == span);
 
+            string_span<> _span{ _ptr, 5 };
+
+            // non-const span, non-const other type
+            
             CHECK(_span == _ar);
             CHECK(_span == _ar1);
             CHECK(_span == _ar2);
+#ifdef CONFIRM_COMPILATION_ERRORS
             CHECK(_span == _ptr);
+#endif
             CHECK(_span == _str);
             CHECK(_span == _vec);
+            CHECK(_span == _sp);
+
+            CHECK(_ar == _span);
+            CHECK(_ar1 == _span);
+            CHECK(_ar2 == _span);
+#ifdef CONFIRM_COMPILATION_ERRORS
+            CHECK(_ptr == _span);
+#endif
+            CHECK(_str == _span);
+            CHECK(_vec == _span);
+            CHECK(_sp == _span);
+
+            // non-const span, const other type
 
             CHECK(_span == "Hello");
             CHECK(_span == ar);
             CHECK(_span == ar1);
             CHECK(_span == ar2);
+#ifdef CONFIRM_COMPILATION_ERRORS
             CHECK(_span == ptr);
+#endif
             CHECK(_span == str);
             CHECK(_span == vec);
-        }
+            CHECK(_span == sp);
+
+            CHECK("Hello" == _span);
+            CHECK(ar == _span);
+            CHECK(ar1 == _span);
+            CHECK(ar2 == _span);
+#ifdef CONFIRM_COMPILATION_ERRORS
+            CHECK(ptr == _span);
 #endif
+            CHECK(str == _span);
+            CHECK(vec == _span);
+            CHECK(sp == _span);
+
+            // two spans
+
+            CHECK(_span == span);
+            CHECK(span == _span);
+        }
 
         {
             std::vector<char> str1 = { 'H', 'e', 'l', 'l', 'o' };
@@ -238,7 +326,6 @@ SUITE(string_span_tests)
         }
     }
 
-
     TEST(ComparisonAndImplicitConstructors)
     {
         {
@@ -310,7 +397,7 @@ SUITE(string_span_tests)
             CHECK(span >= string_span<>(vec));
         }
     }
-    TEST(EnzureRemoveZ)
+    TEST(ConstrutorsEnsureZ)
     {
         // remove z from literals
         {
@@ -351,6 +438,18 @@ SUITE(string_span_tests)
         }
 #endif
 
+        // default
+        {
+            cstring_span<> span;
+            CHECK(span.length() == 0);
+        }
+
+        // from nullptr
+        {
+            cstring_span<> span(nullptr);
+            CHECK(span.length() == 0);
+        }
+
         // from string literal
         {
             cstring_span<> span = "Hello";
@@ -378,14 +477,34 @@ SUITE(string_span_tests)
             CHECK(span.length() == 5);
         }
 
-        // from non-const ptr and length
+        // from const ptr and length, include 0
         {
-            // does not compile with GCC (ISO standard does not allow converting string literals to char*)
-#ifdef CONFIRM_COMPILATION_ERRORS
-            char* ptr = "Hello";
+            const char* ptr = "Hello";
+            cstring_span<> span{ ptr, 6 };
+            CHECK(span.length() == 6);
+        }
+
+        // from const ptr and length, 0 inside
+        {
+            const char* ptr = "He\0lo";
+            cstring_span<> span{ ptr, 5 };
+            CHECK(span.length() == 5);
+        }
+
+        // from non-const ptr and length
+        {
+            char ar[] = { 'H', 'e', 'l', 'l', 'o' };
+            char* ptr = ar;
+            cstring_span<> span{ ptr, 5 };
+            CHECK(span.length() == 5);
+        }
+
+        // from non-const ptr and length, 0 inside
+        {
+            char ar[] = { 'H', 'e', '\0', 'l', 'o' };
+            char* ptr = ar;
             cstring_span<> span{ ptr, 5 };
             CHECK(span.length() == 5);
-#endif
         }
 
         // from const string

From c6f3579ad1502015e320facf882f54caefbc266b Mon Sep 17 00:00:00 2001
From: Anna Gringauze <annagrin@microsoft.com>
Date: Sat, 5 Dec 2015 01:03:19 +0000
Subject: [PATCH 41/43] Changes for gcc and clang

---
 include/string_span.h | 212 ++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 204 insertions(+), 8 deletions(-)

diff --git a/include/string_span.h b/include/string_span.h
index 8418029..6b0b32b 100644
--- a/include/string_span.h
+++ b/include/string_span.h
@@ -213,6 +213,7 @@ namespace details
 template <typename CharT, std::ptrdiff_t Extent = dynamic_range>
 class basic_string_span
 {
+public:
     using value_type = CharT;
     using const_value_type = std::add_const_t<value_type>;
     using pointer = std::add_pointer_t<value_type>;
@@ -221,7 +222,6 @@ class basic_string_span
     using bounds_type = static_bounds<Extent>;
     using impl_type = span<value_type, Extent>;
 
-public:
     using size_type = ptrdiff_t;
     using iterator = typename impl_type::iterator;
     using const_iterator = typename impl_type::const_iterator;
@@ -542,7 +542,7 @@ bool operator==(gsl::basic_string_span<CharT, Extent> one, const T& other) noexc
 template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
     typename Dummy = std::enable_if_t<
     std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value
-    && !details::is_basic_string_span<T>::value>
+    && !gsl::details::is_basic_string_span<T>::value>
 >
 bool operator==(const T& one, gsl::basic_string_span<CharT, Extent> other) noexcept
 {
@@ -550,6 +550,40 @@ bool operator==(const T& one, gsl::basic_string_span<CharT, Extent> other) noexc
     return std::equal(tmp.begin(), tmp.end(), other.begin(), other.end());
 }
 
+#ifndef _MSC_VER 
+
+// VS allows temp and const containers as convertible to basic_string_span,
+// to the cases below are already by the revious operators
+
+template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
+    typename DataType = typename T::value_type,
+    typename Dummy = std::enable_if_t<
+    !gsl::details::is_span<T>::value
+    && !gsl::details::is_basic_string_span<T>::value
+    && std::is_convertible<DataType*, CharT*>::value
+    && std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>, DataType>::value>
+>
+bool operator==(gsl::basic_string_span<CharT, Extent> one, const T& other) noexcept
+{
+    gsl::basic_string_span<std::add_const_t<CharT>, Extent> tmp(other);
+    return std::equal(one.begin(), one.end(), tmp.begin(), tmp.end());
+}
+
+template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
+    typename DataType = typename T::value_type,
+    typename Dummy = std::enable_if_t<
+    !gsl::details::is_span<T>::value
+    && !gsl::details::is_basic_string_span<T>::value
+    && std::is_convertible<DataType*, CharT*>::value
+    && std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>, DataType>::value>
+>
+bool operator==(const T& one, gsl::basic_string_span<CharT, Extent> other) noexcept
+{
+    gsl::basic_string_span<std::add_const_t<CharT>, Extent> tmp(one);
+    return std::equal(tmp.begin(), tmp.end(), other.begin(), other.end());
+}
+#endif
+
 // operator !=
 template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
     typename = std::enable_if_t<
@@ -563,13 +597,45 @@ bool operator!=(gsl::basic_string_span<CharT, Extent> one, const T& other) noexc
 template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
     typename Dummy = std::enable_if_t<
     std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value
-    && !details::is_basic_string_span<T>::value>
+    && !gsl::details::is_basic_string_span<T>::value>
 >
 bool operator!=(const T& one, gsl::basic_string_span<CharT, Extent> other) noexcept
 {
     return !(one == other);
 }
 
+#ifndef _MSC_VER 
+
+// VS allows temp and const containers as convertible to basic_string_span,
+// to the cases below are already by the revious operators
+
+template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
+    typename DataType = typename T::value_type,
+    typename Dummy = std::enable_if_t<
+    !gsl::details::is_span<T>::value
+    && !gsl::details::is_basic_string_span<T>::value
+    && std::is_convertible<DataType*, CharT*>::value
+    && std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>, DataType>::value>
+>
+bool operator!=(gsl::basic_string_span<CharT, Extent> one, const T& other) noexcept
+{
+    return !(one == other);
+}
+
+template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
+    typename DataType = typename T::value_type,
+    typename Dummy = std::enable_if_t<
+    !gsl::details::is_span<T>::value
+    && !gsl::details::is_basic_string_span<T>::value
+    && std::is_convertible<DataType*, CharT*>::value
+    && std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>, DataType>::value>
+>
+bool operator!=(const T& one, gsl::basic_string_span<CharT, Extent> other) noexcept
+{
+    return !(one == other);
+}
+#endif
+
 // operator<
 template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
     typename = std::enable_if_t<
@@ -578,13 +644,13 @@ template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T
 bool operator<(gsl::basic_string_span<CharT, Extent> one, const T& other) noexcept
 {
     gsl::basic_string_span<std::add_const_t<CharT>, Extent> tmp(other);
-    return std::lexicographical_compare(one.begin(), one.end(), other.begin(), other.end());
+    return std::lexicographical_compare(one.begin(), one.end(), tmp.begin(), tmp.end());
 }
 
 template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
     typename Dummy = std::enable_if_t<
     std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value
-    && !details::is_basic_string_span<T>::value>
+    && !gsl::details::is_basic_string_span<T>::value>
 >
 bool operator<(const T& one, gsl::basic_string_span<CharT, Extent> other) noexcept
 {
@@ -592,6 +658,40 @@ bool operator<(const T& one, gsl::basic_string_span<CharT, Extent> other) noexce
     return std::lexicographical_compare(tmp.begin(), tmp.end(), other.begin(), other.end());
 }
 
+#ifndef _MSC_VER 
+
+// VS allows temp and const containers as convertible to basic_string_span,
+// to the cases below are already by the revious operators
+
+template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
+    typename DataType = typename T::value_type,
+    typename Dummy = std::enable_if_t<
+    !gsl::details::is_span<T>::value
+    && !gsl::details::is_basic_string_span<T>::value
+    && std::is_convertible<DataType*, CharT*>::value
+    && std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>, DataType>::value>
+>
+bool operator<(gsl::basic_string_span<CharT, Extent> one, const T& other) noexcept
+{
+    gsl::basic_string_span<std::add_const_t<CharT>, Extent> tmp(other);
+    return std::lexicographical_compare(one.begin(), one.end(), tmp.begin(), tmp.end());
+}
+
+template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
+    typename DataType = typename T::value_type,
+    typename Dummy = std::enable_if_t<
+    !gsl::details::is_span<T>::value
+    && !gsl::details::is_basic_string_span<T>::value
+    && std::is_convertible<DataType*, CharT*>::value
+    && std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>, DataType>::value>
+>
+bool operator<(const T& one, gsl::basic_string_span<CharT, Extent> other) noexcept
+{
+    gsl::basic_string_span<std::add_const_t<CharT>, Extent> tmp(one);
+    return std::lexicographical_compare(tmp.begin(), tmp.end(), other.begin(), other.end());
+}
+#endif
+
 // operator <=
 template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
     typename = std::enable_if_t<
@@ -605,13 +705,45 @@ bool operator<=(gsl::basic_string_span<CharT, Extent> one, const T& other) noexc
 template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
     typename Dummy = std::enable_if_t<
     std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value
-    && !details::is_basic_string_span<T>::value>
+    && !gsl::details::is_basic_string_span<T>::value>
 >
 bool operator<=(const T& one, gsl::basic_string_span<CharT, Extent> other) noexcept
 {
     return !(other < one);
 }
 
+#ifndef _MSC_VER 
+
+// VS allows temp and const containers as convertible to basic_string_span,
+// to the cases below are already by the revious operators
+
+template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
+    typename DataType = typename T::value_type,
+    typename Dummy = std::enable_if_t<
+    !gsl::details::is_span<T>::value
+    && !gsl::details::is_basic_string_span<T>::value
+    && std::is_convertible<DataType*, CharT*>::value
+    && std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>, DataType>::value>
+>
+bool operator<=(gsl::basic_string_span<CharT, Extent> one, const T& other) noexcept
+{
+    return !(other < one);
+}
+
+template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
+    typename DataType = typename T::value_type,
+    typename Dummy = std::enable_if_t<
+    !gsl::details::is_span<T>::value
+    && !gsl::details::is_basic_string_span<T>::value
+    && std::is_convertible<DataType*, CharT*>::value
+    && std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>, DataType>::value>
+>
+bool operator<=(const T& one, gsl::basic_string_span<CharT, Extent> other) noexcept
+{
+    return !(other < one);
+}
+#endif
+
 // operator>
 template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
     typename = std::enable_if_t<
@@ -625,13 +757,45 @@ bool operator>(gsl::basic_string_span<CharT, Extent> one, const T& other) noexce
 template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
     typename Dummy = std::enable_if_t<
     std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value
-    && !details::is_basic_string_span<T>::value>
+    && !gsl::details::is_basic_string_span<T>::value>
 >
 bool operator>(const T& one, gsl::basic_string_span<CharT, Extent> other) noexcept
 {
     return other < one;
 }
 
+#ifndef _MSC_VER 
+
+// VS allows temp and const containers as convertible to basic_string_span,
+// to the cases below are already by the revious operators
+
+template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
+    typename DataType = typename T::value_type,
+    typename Dummy = std::enable_if_t<
+    !gsl::details::is_span<T>::value
+    && !gsl::details::is_basic_string_span<T>::value
+    && std::is_convertible<DataType*, CharT*>::value
+    && std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>, DataType>::value>
+>
+bool operator>(gsl::basic_string_span<CharT, Extent> one, const T& other) noexcept
+{
+    return other < one;
+}
+
+template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
+    typename DataType = typename T::value_type,
+    typename Dummy = std::enable_if_t<
+    !gsl::details::is_span<T>::value
+    && !gsl::details::is_basic_string_span<T>::value
+    && std::is_convertible<DataType*, CharT*>::value
+    && std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>, DataType>::value>
+>
+bool operator>(const T& one, gsl::basic_string_span<CharT, Extent> other) noexcept
+{
+    return other < one;
+}
+#endif
+
 // operator >=
 template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
     typename = std::enable_if_t<
@@ -645,13 +809,45 @@ bool operator>=(gsl::basic_string_span<CharT, Extent> one, const T& other) noexc
 template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
     typename Dummy = std::enable_if_t<
     std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value
-    && !details::is_basic_string_span<T>::value>
+    && !gsl::details::is_basic_string_span<T>::value>
 >
 bool operator>=(const T& one, gsl::basic_string_span<CharT, Extent> other) noexcept
 {
     return !(one < other);
 }
 
+#ifndef _MSC_VER 
+
+// VS allows temp and const containers as convertible to basic_string_span,
+// to the cases below are already by the revious operators
+
+template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
+    typename DataType = typename T::value_type,
+    typename Dummy = std::enable_if_t<
+    !gsl::details::is_span<T>::value
+    && !gsl::details::is_basic_string_span<T>::value
+    && std::is_convertible<DataType*, CharT*>::value
+    && std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>, DataType>::value>
+>
+bool operator>=(gsl::basic_string_span<CharT, Extent> one, const T& other) noexcept
+{
+    return !(one < other);
+}
+
+template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
+    typename DataType = typename T::value_type,
+    typename Dummy = std::enable_if_t<
+    !gsl::details::is_span<T>::value
+    && !gsl::details::is_basic_string_span<T>::value
+    && std::is_convertible<DataType*, CharT*>::value
+    && std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>, DataType>::value>
+>
+bool operator>=(const T& one, gsl::basic_string_span<CharT, Extent> other) noexcept
+{
+    return !(one < other);
+}
+#endif
+
 // VS 2013 workarounds
 #ifdef _MSC_VER
 

From e19f6b5f362aac677b369b9e2b46010df13cf944 Mon Sep 17 00:00:00 2001
From: Anna Gringauze <annagrin@microsoft.com>
Date: Mon, 7 Dec 2015 15:22:11 -0800
Subject: [PATCH 42/43] Fixed a bug on creating a span from empty string

---
 include/string_span.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/string_span.h b/include/string_span.h
index 6b0b32b..d3419ee 100644
--- a/include/string_span.h
+++ b/include/string_span.h
@@ -270,7 +270,7 @@ public:
 
     // from string
     constexpr basic_string_span(std::string& s) noexcept
-        : span_(&(s.at(0)), narrow_cast<std::ptrdiff_t>(s.length()))
+        : span_(const_cast<pointer>(s.data()), narrow_cast<std::ptrdiff_t>(s.length()))
     {}
 
     // from containers. Containers must have .size() and .data() function signatures

From 5926942cd7b8270dc851297b27e995bc5d32ab7d Mon Sep 17 00:00:00 2001
From: Anna Gringauze <annagrin@microsoft.com>
Date: Mon, 7 Dec 2015 15:30:00 -0800
Subject: [PATCH 43/43] Tyding up comments

---
 include/string_span.h | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/include/string_span.h b/include/string_span.h
index d3419ee..a451314 100644
--- a/include/string_span.h
+++ b/include/string_span.h
@@ -552,8 +552,8 @@ bool operator==(const T& one, gsl::basic_string_span<CharT, Extent> other) noexc
 
 #ifndef _MSC_VER 
 
-// VS allows temp and const containers as convertible to basic_string_span,
-// to the cases below are already by the revious operators
+// VS treats temp and const containers as convertible to basic_string_span,
+// so the cases below are already covered by the previous operators
 
 template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
     typename DataType = typename T::value_type,
@@ -606,8 +606,8 @@ bool operator!=(const T& one, gsl::basic_string_span<CharT, Extent> other) noexc
 
 #ifndef _MSC_VER 
 
-// VS allows temp and const containers as convertible to basic_string_span,
-// to the cases below are already by the revious operators
+// VS treats temp and const containers as convertible to basic_string_span,
+// so the cases below are already covered by the previous operators
 
 template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
     typename DataType = typename T::value_type,
@@ -660,8 +660,8 @@ bool operator<(const T& one, gsl::basic_string_span<CharT, Extent> other) noexce
 
 #ifndef _MSC_VER 
 
-// VS allows temp and const containers as convertible to basic_string_span,
-// to the cases below are already by the revious operators
+// VS treats temp and const containers as convertible to basic_string_span,
+// so the cases below are already covered by the previous operators
 
 template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
     typename DataType = typename T::value_type,
@@ -714,8 +714,8 @@ bool operator<=(const T& one, gsl::basic_string_span<CharT, Extent> other) noexc
 
 #ifndef _MSC_VER 
 
-// VS allows temp and const containers as convertible to basic_string_span,
-// to the cases below are already by the revious operators
+// VS treats temp and const containers as convertible to basic_string_span,
+// so the cases below are already covered by the previous operators
 
 template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
     typename DataType = typename T::value_type,
@@ -766,8 +766,8 @@ bool operator>(const T& one, gsl::basic_string_span<CharT, Extent> other) noexce
 
 #ifndef _MSC_VER 
 
-// VS allows temp and const containers as convertible to basic_string_span,
-// to the cases below are already by the revious operators
+// VS treats temp and const containers as convertible to basic_string_span,
+// so the cases below are already covered by the previous operators
 
 template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
     typename DataType = typename T::value_type,
@@ -818,8 +818,8 @@ bool operator>=(const T& one, gsl::basic_string_span<CharT, Extent> other) noexc
 
 #ifndef _MSC_VER 
 
-// VS allows temp and const containers as convertible to basic_string_span,
-// to the cases below are already by the revious operators
+// VS treats temp and const containers as convertible to basic_string_span,
+// so the cases below are already covered by the previous operators
 
 template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_range, typename T,
     typename DataType = typename T::value_type,