TartanLlama/optional
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Constexpr

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This commit is contained in:
Simon Brand
2017-10-01 22:08:36 +01:00
parent 29820df89b
commit 60e9b2867b
1 changed files with 20 additions and 44 deletions
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64
optional.hpp
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@@ -142,57 +142,27 @@ namespace tl {
// [optional.relops], relational operators
template <class T, class U>
inline constexpr bool operator==(const optional<T>& lhs, const optional<U>& rhs) {
if (lhs.has_value() != rhs.has_value())
return false;
if (lhs.has_value())
return true;
return *lhs == *rhs;
return lhs.has_value() == rhs.has_value() && (!lhs.has_value() || *lhs == *rhs);
}
template <class T, class U>
inline constexpr bool operator!=(const optional<T>& lhs, const optional<U>& rhs) {
if (lhs.has_value() != rhs.has_value())
return true;
if (lhs.has_value())
return false;
return *lhs != *rhs;
return lhs.has_value() != rhs.has_value() || (lhs.has_value() && *lhs != *rhs);
}
template <class T, class U>
inline constexpr bool operator<(const optional<T>& lhs, const optional<U>& rhs) {
if (!rhs.has_value())
return false;
if (!lhs.has_value())
return true;
return *lhs < *rhs;
return rhs.has_value() && (!lhs.has_value() || *lhs < *rhs);
}
template <class T, class U>
inline constexpr bool operator>(const optional<T>& lhs, const optional<U>& rhs) {
if (!lhs.has_value())
return false;
if (!rhs.has_value())
return true;
return *lhs > *rhs;
return lhs.has_value() && (!rhs.has_value() || *lhs > *rhs);
}
template <class T, class U>
inline constexpr bool operator<=(const optional<T>& lhs, const optional<U>& rhs) {
if (!lhs.has_value())
return true;
if (!rhs.has_value())
return false;
return *lhs <= *rhs;
return !lhs.has_value() || (rhs.has_value() && *lhs <= *rhs);
}
template <class T, class U>
inline constexpr bool operator>=(const optional<T>& lhs, const optional<U>& rhs) {
if (!rhs.has_value())
return true;
if (!lhs.has_value())
return false;
return *lhs >= *rhs;
return !rhs.has_value() || (lhs.has_value() && *lhs >= *rhs);
}
// [optional.nullops], comparison with nullopt
@@ -313,6 +283,11 @@ namespace tl {
struct optional_storage_base {
constexpr optional_storage_base() noexcept
: m_dummy(), m_has_value(false) {}
template <class U>
constexpr optional_storage_base(in_place_t, U&& u) noexcept
: m_value(std::forward<U>(u)), m_has_value(true) {}
~optional_storage_base() {
if (m_has_value) {
m_value.~T();
@@ -333,6 +308,12 @@ namespace tl {
struct optional_storage_base<T, true> {
constexpr optional_storage_base() noexcept
: m_dummy(), m_has_value(false) {}
template <class U>
constexpr optional_storage_base(in_place_t, U&& u) noexcept
: m_value(std::forward<U>(u)), m_has_value(true) {}
~optional_storage_base() = default;
struct dummy{};
@@ -347,6 +328,7 @@ namespace tl {
template <class T>
class optional : private detail::optional_storage_base<T> {
using base = detail::optional_storage_base<T>;
public:
using value_type = T;
@@ -383,17 +365,11 @@ namespace tl {
template <class U = T, enable_if_t<std::is_convertible<U&&, T>::value>* = nullptr,
detail::enable_forward_value<T,U>* = nullptr>
constexpr optional(U&& u) {
this->m_has_value = true;
new (std::addressof(this->m_value)) T (std::forward<U>(u));
}
constexpr optional(U&& u) : base(in_place, std::forward<U>(u)) {}
template <class U = T, enable_if_t<!std::is_convertible<U&&, T>::value>* = nullptr,
detail::enable_forward_value<T,U>* = nullptr>
constexpr explicit optional(U&& u) {
this->m_has_value = true;
new (std::addressof(this->m_value)) T (std::forward<U>(u));
}
constexpr explicit optional(U&& u) : base(in_place, std::forward<U>(u)) {}
template <class U, detail::enable_from_other<T,U,const U&>* = nullptr,
enable_if_t<std::is_convertible<const U&, T>::value>* = nullptr>