diff options
Diffstat (limited to 'libstdc++-v3/include/experimental/optional')
| -rw-r--r-- | libstdc++-v3/include/experimental/optional | 148 |
1 files changed, 146 insertions, 2 deletions
diff --git a/libstdc++-v3/include/experimental/optional b/libstdc++-v3/include/experimental/optional index 7524a7e135..b6425b7d00 100644 --- a/libstdc++-v3/include/experimental/optional +++ b/libstdc++-v3/include/experimental/optional @@ -470,6 +470,23 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION bool _M_engaged = false; }; + template<typename _Tp> + class optional; + + template<typename> + struct __is_optional_impl : false_type + { }; + + template<typename _Tp> + struct __is_optional_impl<optional<_Tp>> : true_type + { }; + + template<typename _Tp> + struct __is_optional + : public __is_optional_impl<std::remove_cv_t<std::remove_reference_t<_Tp>>> + { }; + + /** * @brief Class template for optional values. */ @@ -502,6 +519,78 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION // _Optional_base has the responsibility for construction. using _Base::_Base; + constexpr optional() = default; + // Converting constructors for engaged optionals. + template <typename _Up, + enable_if_t<__and_< + __not_<is_same<_Tp, _Up>>, + is_constructible<_Tp, _Up&&>, + is_convertible<_Up&&, _Tp> + >::value, bool> = true> + constexpr optional(_Up&& __t) + : _Base(_Tp(std::forward<_Up>(__t))) { } + + template <typename _Up, + enable_if_t<__and_< + __not_<is_same<_Tp, _Up>>, + is_constructible<_Tp, _Up&&>, + __not_<is_convertible<_Up&&, _Tp>> + >::value, bool> = false> + explicit constexpr optional(_Up&& __t) + : _Base(_Tp(std::forward<_Up>(__t))) { } + + template <typename _Up, + enable_if_t<__and_< + __not_<is_same<_Tp, _Up>>, + __not_<is_constructible< + _Tp, const optional<_Up>&>>, + __not_<is_convertible< + const optional<_Up>&, _Tp>>, + is_constructible<_Tp, const _Up&>, + is_convertible<const _Up&, _Tp> + >::value, bool> = true> + constexpr optional(const optional<_Up>& __t) + : _Base(__t ? optional<_Tp>(*__t) : optional<_Tp>()) { } + + template <typename _Up, + enable_if_t<__and_< + __not_<is_same<_Tp, _Up>>, + __not_<is_constructible< + _Tp, const optional<_Up>&>>, + __not_<is_convertible< + const optional<_Up>&, _Tp>>, + is_constructible<_Tp, const _Up&>, + __not_<is_convertible<const _Up&, _Tp>> + >::value, bool> = false> + explicit constexpr optional(const optional<_Up>& __t) + : _Base(__t ? optional<_Tp>(*__t) : optional<_Tp>()) { } + + template <typename _Up, + enable_if_t<__and_< + __not_<is_same<_Tp, _Up>>, + __not_<is_constructible< + _Tp, optional<_Up>&&>>, + __not_<is_convertible< + optional<_Up>&&, _Tp>>, + is_constructible<_Tp, _Up&&>, + is_convertible<_Up&&, _Tp> + >::value, bool> = true> + constexpr optional(optional<_Up>&& __t) + : _Base(__t ? optional<_Tp>(std::move(*__t)) : optional<_Tp>()) { } + + template <typename _Up, + enable_if_t<__and_< + __not_<is_same<_Tp, _Up>>, + __not_<is_constructible< + _Tp, optional<_Up>&&>>, + __not_<is_convertible< + optional<_Up>&&, _Tp>>, + is_constructible<_Tp, _Up&&>, + __not_<is_convertible<_Up&&, _Tp>> + >::value, bool> = false> + explicit constexpr optional(optional<_Up>&& __t) + : _Base(__t ? optional<_Tp>(std::move(*__t)) : optional<_Tp>()) { } + // [X.Y.4.3] (partly) Assignment. optional& operator=(nullopt_t) noexcept @@ -510,8 +599,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION return *this; } - template<typename _Up> - enable_if_t<is_same<_Tp, decay_t<_Up>>::value, optional&> + template<typename _Up, + enable_if_t<__and_< + __not_<is_same<_Up, nullopt_t>>, + __not_<__is_optional<_Up>>>::value, + bool> = true> + optional& operator=(_Up&& __u) { static_assert(__and_<is_constructible<_Tp, _Up>, @@ -526,6 +619,57 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION return *this; } + template<typename _Up, + enable_if_t<__and_< + __not_<is_same<_Tp, _Up>>>::value, + bool> = true> + optional& + operator=(const optional<_Up>& __u) + { + static_assert(__and_<is_constructible<_Tp, _Up>, + is_assignable<_Tp&, _Up>>(), + "Cannot assign to value type from argument"); + + if (__u) + { + if (this->_M_is_engaged()) + this->_M_get() = *__u; + else + this->_M_construct(*__u); + } + else + { + this->_M_reset(); + } + return *this; + } + + template<typename _Up, + enable_if_t<__and_< + __not_<is_same<_Tp, _Up>>>::value, + bool> = true> + optional& + operator=(optional<_Up>&& __u) + { + static_assert(__and_<is_constructible<_Tp, _Up>, + is_assignable<_Tp&, _Up>>(), + "Cannot assign to value type from argument"); + + if (__u) + { + if (this->_M_is_engaged()) + this->_M_get() = std::move(*__u); + else + this->_M_construct(std::move(*__u)); + } + else + { + this->_M_reset(); + } + + return *this; + } + template<typename... _Args> void emplace(_Args&&... __args) |