Implement allocate_unique

include/boost/smart_ptr/allocate_unique.hpp

@@ -0,0 +1,501 @@
+/*
+Copyright 2019 Glen Joseph Fernandes
+(glenjofe@gmail.com)
+
+Distributed under the Boost Software License, Version 1.0.
+(http://www.boost.org/LICENSE_1_0.txt)
+*/
+#ifndef BOOST_SMART_PTR_ALLOCATE_UNIQUE_HPP
+#define BOOST_SMART_PTR_ALLOCATE_UNIQUE_HPP
+
+#include <boost/smart_ptr/detail/sp_noexcept.hpp>
+#include <boost/smart_ptr/detail/sp_nullptr_t.hpp>
+#include <boost/core/alloc_construct.hpp>
+#include <boost/core/empty_value.hpp>
+#include <boost/core/first_scalar.hpp>
+#include <boost/core/noinit_adaptor.hpp>
+#include <boost/core/pointer_traits.hpp>
+#include <boost/type_traits/enable_if.hpp>
+#include <boost/type_traits/extent.hpp>
+#include <boost/type_traits/is_array.hpp>
+#include <boost/type_traits/is_bounded_array.hpp>
+#include <boost/type_traits/is_unbounded_array.hpp>
+#include <boost/type_traits/remove_cv.hpp>
+#include <boost/type_traits/remove_extent.hpp>
+#include <boost/type_traits/type_identity.hpp>
+#include <boost/config.hpp>
+#include <memory>
+#include <utility>
+
+namespace boost {
+namespace detail {
+
+template<class T>
+struct sp_alloc_size {
+    BOOST_STATIC_CONSTEXPR std::size_t value = 1;
+};
+
+template<class T>
+struct sp_alloc_size<T[]> {
+    BOOST_STATIC_CONSTEXPR std::size_t value = sp_alloc_size<T>::value;
+};
+
+template<class T, std::size_t N>
+struct sp_alloc_size<T[N]> {
+    BOOST_STATIC_CONSTEXPR std::size_t value = N * sp_alloc_size<T>::value;
+};
+
+template<class T>
+struct sp_alloc_result {
+    typedef T type;
+};
+
+template<class T, std::size_t N>
+struct sp_alloc_result<T[N]> {
+    typedef T type[];
+};
+
+template<class T>
+struct sp_alloc_value {
+    typedef typename boost::remove_cv<typename
+        boost::remove_extent<T>::type>::type type;
+};
+
+#if !defined(BOOST_NO_CXX11_ALLOCATOR)
+template<class A, class T>
+struct sp_alloc_to {
+    typedef typename std::allocator_traits<A>::template rebind_alloc<T> type;
+};
+#else
+template<class A, class T>
+struct sp_alloc_to {
+    typedef typename A::template rebind<T>::other type;
+};
+#endif
+
+#if !defined(BOOST_NO_CXX11_ALLOCATOR)
+template<class A>
+struct sp_alloc_type {
+    typedef typename std::allocator_traits<A>::pointer type;
+};
+#else
+template<class A>
+struct sp_alloc_type {
+    typedef typename A::pointer type;
+};
+#endif
+
+template<class T, class P>
+class sp_alloc_ptr {
+public:
+    typedef T element_type;
+
+    sp_alloc_ptr() BOOST_SP_NOEXCEPT
+        : p_() { }
+
+    sp_alloc_ptr(std::size_t, P p) BOOST_SP_NOEXCEPT
+        : p_(p) { }
+
+#if !defined(BOOST_NO_CXX11_NULLPTR)
+    sp_alloc_ptr(detail::sp_nullptr_t) BOOST_SP_NOEXCEPT
+        : p_() { }
+#endif
+
+    T& operator*() const {
+        return *p_;
+    }
+
+    T* operator->() const BOOST_SP_NOEXCEPT {
+        return boost::to_address(p_);
+    }
+
+#if !defined(BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS)
+    explicit operator bool() const BOOST_SP_NOEXCEPT {
+        return !!p_;
+    }
+#endif
+
+    bool operator!() const BOOST_SP_NOEXCEPT {
+        return !p_;
+    }
+
+    P ptr() const BOOST_SP_NOEXCEPT {
+        return p_;
+    }
+
+    BOOST_STATIC_CONSTEXPR std::size_t size() BOOST_SP_NOEXCEPT {
+        return 1;
+    }
+
+#if defined(BOOST_MSVC) && BOOST_MSVC < 1910
+    static sp_alloc_ptr pointer_to(T& v) {
+        return sp_alloc_ptr(1,
+            std::pointer_traits<P>::pointer_to(const_cast<typename
+                boost::remove_cv<T>::type&>(v)));
+    }
+#endif
+
+private:
+    P p_;
+};
+
+template<class T, class P>
+class sp_alloc_ptr<T[], P> {
+public:
+    typedef T element_type;
+
+    sp_alloc_ptr() BOOST_SP_NOEXCEPT
+        : p_() { }
+
+    sp_alloc_ptr(std::size_t n, P p) BOOST_SP_NOEXCEPT
+        : p_(p)
+        , n_(n) { }
+
+#if !defined(BOOST_NO_CXX11_NULLPTR)
+    sp_alloc_ptr(detail::sp_nullptr_t) BOOST_SP_NOEXCEPT
+        : p_() { }
+#endif
+
+    T& operator[](std::size_t i) const {
+        return p_[i];
+    }
+
+#if !defined(BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS)
+    explicit operator bool() const BOOST_SP_NOEXCEPT {
+        return !!p_;
+    }
+#endif
+
+    bool operator!() const BOOST_SP_NOEXCEPT {
+        return !p_;
+    }
+
+    P ptr() const BOOST_SP_NOEXCEPT {
+        return p_;
+    }
+
+    std::size_t size() const BOOST_SP_NOEXCEPT {
+        return n_;
+    }
+
+#if defined(BOOST_MSVC) && BOOST_MSVC < 1910
+    static sp_alloc_ptr pointer_to(T& v) {
+        return sp_alloc_ptr(n_,
+            std::pointer_traits<P>::pointer_to(const_cast<typename
+                boost::remove_cv<T>::type&>(v)));
+    }
+#endif
+
+private:
+    P p_;
+    std::size_t n_;
+};
+
+template<class T, std::size_t N, class P>
+class sp_alloc_ptr<T[N], P> {
+public:
+    typedef T element_type;
+
+    sp_alloc_ptr() BOOST_SP_NOEXCEPT
+        : p_() { }
+
+    sp_alloc_ptr(std::size_t, P p) BOOST_SP_NOEXCEPT
+        : p_(p) { }
+
+#if !defined(BOOST_NO_CXX11_NULLPTR)
+    sp_alloc_ptr(detail::sp_nullptr_t) BOOST_SP_NOEXCEPT
+        : p_() { }
+#endif
+
+    T& operator[](std::size_t i) const {
+        return p_[i];
+    }
+
+#if !defined(BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS)
+    explicit operator bool() const BOOST_SP_NOEXCEPT {
+        return !!p_;
+    }
+#endif
+
+    bool operator!() const BOOST_SP_NOEXCEPT {
+        return !p_;
+    }
+
+    P ptr() const BOOST_SP_NOEXCEPT {
+        return p_;
+    }
+
+    BOOST_STATIC_CONSTEXPR std::size_t size() BOOST_SP_NOEXCEPT {
+        return N;
+    }
+
+#if defined(BOOST_MSVC) && BOOST_MSVC < 1910
+    static sp_alloc_ptr pointer_to(T& v) {
+        return sp_alloc_ptr(N,
+            std::pointer_traits<P>::pointer_to(const_cast<typename
+                boost::remove_cv<T>::type&>(v)));
+    }
+#endif
+
+private:
+    P p_;
+};
+
+template<class T, class P>
+inline bool
+operator==(const sp_alloc_ptr<T, P>& lhs, const sp_alloc_ptr<T, P>& rhs)
+{
+    return lhs.ptr() == rhs.ptr();
+}
+
+template<class T, class P>
+inline bool
+operator!=(const sp_alloc_ptr<T, P>& lhs, const sp_alloc_ptr<T, P>& rhs)
+{
+    return !(lhs == rhs);
+}
+
+#if !defined(BOOST_NO_CXX11_NULLPTR)
+template<class T, class P>
+inline bool
+operator==(const sp_alloc_ptr<T, P>& lhs,
+    detail::sp_nullptr_t) BOOST_SP_NOEXCEPT
+{
+    return !lhs.ptr();
+}
+
+template<class T, class P>
+inline bool
+operator==(detail::sp_nullptr_t,
+    const sp_alloc_ptr<T, P>& rhs) BOOST_SP_NOEXCEPT
+{
+    return !rhs.ptr();
+}
+
+template<class T, class P>
+inline bool
+operator!=(const sp_alloc_ptr<T, P>& lhs,
+    detail::sp_nullptr_t) BOOST_SP_NOEXCEPT
+{
+    return !!lhs.ptr();
+}
+
+template<class T, class P>
+inline bool
+operator!=(detail::sp_nullptr_t,
+    const sp_alloc_ptr<T, P>& rhs) BOOST_SP_NOEXCEPT
+{
+    return !!rhs.ptr();
+}
+#endif
+
+template<class A>
+inline void
+sp_alloc_clear(A& a, typename sp_alloc_type<A>::type p, std::size_t,
+    boost::false_type)
+{
+    boost::alloc_destroy(a, p);
+    a.deallocate(p, 1);
+}
+
+template<class A>
+inline void
+sp_alloc_clear(A& a, typename sp_alloc_type<A>::type p, std::size_t n,
+    boost::true_type)
+{
+#if defined(BOOST_MSVC) && BOOST_MSVC < 1800
+    if (!p) {
+        return;
+    }
+#endif
+    boost::alloc_destroy_n(a, boost::first_scalar(boost::to_address(p)),
+        n * sp_alloc_size<typename A::value_type>::value);
+    a.deallocate(p, n);
+}
+
+} /* detail */
+
+template<class T, class A>
+class alloc_deleter
+    : empty_value<typename detail::sp_alloc_to<A,
+        typename detail::sp_alloc_value<T>::type>::type> {
+    typedef typename detail::sp_alloc_to<A,
+        typename detail::sp_alloc_value<T>::type>::type allocator;
+    typedef empty_value<allocator> base;
+
+public:
+    typedef detail::sp_alloc_ptr<T,
+        typename detail::sp_alloc_type<allocator>::type> pointer;
+
+    explicit alloc_deleter(const allocator& a) BOOST_SP_NOEXCEPT
+        : base(empty_init_t(), a) { }
+
+    void operator()(pointer p) {
+        detail::sp_alloc_clear(base::get(), p.ptr(), p.size(), is_array<T>());
+    }
+};
+
+#if !defined(BOOST_NO_CXX11_TEMPLATE_ALIASES)
+template<class T, class A>
+using alloc_noinit_deleter = alloc_deleter<T, noinit_adaptor<A> >;
+#endif
+
+namespace detail {
+
+template<class T, class A>
+class sp_alloc_make {
+public:
+    typedef typename sp_alloc_to<A,
+        typename sp_alloc_value<T>::type>::type allocator;
+
+private:
+    typedef boost::alloc_deleter<T, A> deleter;
+
+public:
+    typedef std::unique_ptr<typename sp_alloc_result<T>::type, deleter> type;
+
+    sp_alloc_make(const A& a, std::size_t n)
+        : a_(a)
+        , n_(n)
+        , p_(a_.allocate(n)) { }
+
+    ~sp_alloc_make() {
+        if (p_) {
+            a_.deallocate(p_, n_);
+        }
+    }
+
+    typename allocator::value_type* get() const BOOST_SP_NOEXCEPT {
+        return boost::to_address(p_);
+    }
+
+    allocator& state() BOOST_SP_NOEXCEPT {
+        return a_;
+    }
+
+    type release() BOOST_SP_NOEXCEPT {
+        pointer p = p_;
+        p_ = pointer();
+        return type(typename deleter::pointer(n_, p), deleter(a_));
+    }
+
+private:
+    typedef typename sp_alloc_type<allocator>::type pointer;
+
+    allocator a_;
+    std::size_t n_;
+    pointer p_;
+};
+
+} /* detail */
+
+template<class T, class A>
+inline typename enable_if_<!is_array<T>::value,
+    std::unique_ptr<T, alloc_deleter<T, A> > >::type
+allocate_unique(const A& alloc)
+{
+    detail::sp_alloc_make<T, A> c(alloc, 1);
+    boost::alloc_construct(c.state(), c.get());
+    return c.release();
+}
+
+#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
+template<class T, class A, class... Args>
+inline typename enable_if_<!is_array<T>::value,
+    std::unique_ptr<T, alloc_deleter<T, A> > >::type
+allocate_unique(const A& alloc, Args&&... args)
+{
+    detail::sp_alloc_make<T, A> c(alloc, 1);
+    boost::alloc_construct(c.state(), c.get(), std::forward<Args>(args)...);
+    return c.release();
+}
+#endif
+
+template<class T, class A>
+inline typename enable_if_<!is_array<T>::value,
+    std::unique_ptr<T, alloc_deleter<T, A> > >::type
+allocate_unique(const A& alloc, typename type_identity<T>::type&& value)
+{
+    detail::sp_alloc_make<T, A> c(alloc, 1);
+    boost::alloc_construct(c.state(), c.get(), std::move(value));
+    return c.release();
+}
+
+template<class T, class A>
+inline typename enable_if_<!is_array<T>::value,
+    std::unique_ptr<T, alloc_deleter<T, noinit_adaptor<A> > > >::type
+allocate_unique_noinit(const A& alloc)
+{
+    return boost::allocate_unique<T, noinit_adaptor<A> >(alloc);
+}
+
+template<class T, class A>
+inline typename enable_if_<is_unbounded_array<T>::value,
+    std::unique_ptr<T, alloc_deleter<T, A> > >::type
+allocate_unique(const A& alloc, std::size_t size)
+{
+    detail::sp_alloc_make<T, A> c(alloc, size);
+    boost::alloc_construct_n(c.state(), boost::first_scalar(c.get()),
+        size * detail::sp_alloc_size<T>::value);
+    return c.release();
+}
+
+template<class T, class A>
+inline typename enable_if_<is_bounded_array<T>::value,
+    std::unique_ptr<typename detail::sp_alloc_result<T>::type,
+        alloc_deleter<T, A> > >::type
+allocate_unique(const A& alloc)
+{
+    detail::sp_alloc_make<T, A> c(alloc, extent<T>::value);
+    boost::alloc_construct_n(c.state(), boost::first_scalar(c.get()),
+        detail::sp_alloc_size<T>::value);
+    return c.release();
+}
+
+template<class T, class A>
+inline typename enable_if_<is_unbounded_array<T>::value,
+    std::unique_ptr<T, alloc_deleter<T, noinit_adaptor<A> > > >::type
+allocate_unique_noinit(const A& alloc, std::size_t size)
+{
+    return boost::allocate_unique<T, noinit_adaptor<A> >(alloc, size);
+}
+
+template<class T, class A>
+inline typename enable_if_<is_bounded_array<T>::value,
+    std::unique_ptr<typename detail::sp_alloc_result<T>::type,
+        alloc_deleter<T, noinit_adaptor<A> > > >::type
+allocate_unique_noinit(const A& alloc)
+{
+    return boost::allocate_unique<T, noinit_adaptor<A> >(alloc);
+}
+
+template<class T, class A>
+inline typename enable_if_<is_unbounded_array<T>::value,
+    std::unique_ptr<T, alloc_deleter<T, A> > >::type
+allocate_unique(const A& alloc, std::size_t size,
+    const typename remove_extent<T>::type& value)
+{
+    detail::sp_alloc_make<T, A> c(alloc, size);
+    boost::alloc_construct_n(c.state(), boost::first_scalar(c.get()),
+        size * detail::sp_alloc_size<T>::value, boost::first_scalar(&value),
+        detail::sp_alloc_size<typename remove_extent<T>::type>::value);
+    return c.release();
+}
+
+template<class T, class A>
+inline typename enable_if_<is_bounded_array<T>::value,
+    std::unique_ptr<typename detail::sp_alloc_result<T>::type,
+        alloc_deleter<T, A> > >::type
+allocate_unique(const A& alloc,
+    const typename remove_extent<T>::type& value)
+{
+    detail::sp_alloc_make<T, A> c(alloc, extent<T>::value);
+    boost::alloc_construct_n(c.state(), boost::first_scalar(c.get()),
+        detail::sp_alloc_size<T>::value, boost::first_scalar(&value),
+        detail::sp_alloc_size<typename remove_extent<T>::type>::value);
+    return c.release();
+}
+
+} /* boost */
+
+#endif