| // <optional> -*- C++ -*- |
| |
| // Copyright (C) 2013-2021 Free Software Foundation, Inc. |
| // |
| // This file is part of the GNU ISO C++ Library. This library is free |
| // software; you can redistribute it and/or modify it under the |
| // terms of the GNU General Public License as published by the |
| // Free Software Foundation; either version 3, or (at your option) |
| // any later version. |
| |
| // This library is distributed in the hope that it will be useful, |
| // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| // GNU General Public License for more details. |
| |
| // Under Section 7 of GPL version 3, you are granted additional |
| // permissions described in the GCC Runtime Library Exception, version |
| // 3.1, as published by the Free Software Foundation. |
| |
| // You should have received a copy of the GNU General Public License and |
| // a copy of the GCC Runtime Library Exception along with this program; |
| // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
| // <http://www.gnu.org/licenses/>. |
| |
| /** @file experimental/optional |
| * This is a TS C++ Library header. |
| * @ingroup libfund-ts |
| */ |
| |
| #ifndef _GLIBCXX_EXPERIMENTAL_OPTIONAL |
| #define _GLIBCXX_EXPERIMENTAL_OPTIONAL 1 |
| |
| #if __cplusplus >= 201402L |
| |
| #include <type_traits> |
| #include <stdexcept> |
| #include <new> |
| #include <initializer_list> |
| #include <bits/functexcept.h> |
| #include <bits/functional_hash.h> |
| #include <bits/enable_special_members.h> |
| #include <bits/move.h> |
| #include <experimental/bits/lfts_config.h> |
| |
| namespace std _GLIBCXX_VISIBILITY(default) |
| { |
| _GLIBCXX_BEGIN_NAMESPACE_VERSION |
| |
| namespace experimental |
| { |
| inline namespace fundamentals_v1 |
| { |
| /** |
| * @defgroup optional Optional values |
| * @ingroup libfund-ts |
| * |
| * Class template for optional values and surrounding facilities, as |
| * described in n3793 "A proposal to add a utility class to represent |
| * optional objects (Revision 5)". |
| * |
| * @{ |
| */ |
| |
| #define __cpp_lib_experimental_optional 201411 |
| |
| // All subsequent [X.Y.n] references are against n3793. |
| |
| // [X.Y.4] |
| template<typename _Tp> |
| class optional; |
| |
| // [X.Y.5] |
| /// Tag type for in-place construction. |
| struct in_place_t { }; |
| |
| /// Tag for in-place construction. |
| constexpr in_place_t in_place { }; |
| |
| // [X.Y.6] |
| /// Tag type to disengage optional objects. |
| struct nullopt_t |
| { |
| // Do not user-declare default constructor at all for |
| // optional_value = {} syntax to work. |
| // nullopt_t() = delete; |
| |
| // Used for constructing nullopt. |
| enum class _Construct { _Token }; |
| |
| // Must be constexpr for nullopt_t to be literal. |
| explicit constexpr nullopt_t(_Construct) { } |
| }; |
| |
| // [X.Y.6] |
| /// Tag to disengage optional objects. |
| constexpr nullopt_t nullopt { nullopt_t::_Construct::_Token }; |
| |
| // [X.Y.7] |
| /** |
| * @brief Exception class thrown when a disengaged optional object is |
| * dereferenced. |
| * @ingroup exceptions |
| */ |
| class bad_optional_access : public logic_error |
| { |
| public: |
| bad_optional_access() : logic_error("bad optional access") { } |
| |
| // XXX This constructor is non-standard. Should not be inline |
| explicit bad_optional_access(const char* __arg) : logic_error(__arg) { } |
| |
| virtual ~bad_optional_access() noexcept = default; |
| }; |
| |
| /// @cond undocumented |
| |
| // XXX Does not belong here. |
| [[noreturn]] inline void |
| __throw_bad_optional_access(const char* __s) |
| { _GLIBCXX_THROW_OR_ABORT(bad_optional_access(__s)); } |
| |
| /** |
| * @brief Class template that holds the necessary state for @ref optional |
| * and that has the responsibility for construction and the special members. |
| * |
| * Such a separate base class template is necessary in order to |
| * conditionally enable the special members (e.g. copy/move constructors). |
| * Note that this means that @ref _Optional_base implements the |
| * functionality for copy and move assignment, but not for converting |
| * assignment. |
| * |
| * @see optional, _Enable_special_members |
| */ |
| template<typename _Tp, bool _ShouldProvideDestructor = |
| !is_trivially_destructible<_Tp>::value> |
| class _Optional_base |
| { |
| private: |
| // Remove const to avoid prohibition of reusing object storage for |
| // const-qualified types in [3.8/9]. This is strictly internal |
| // and even optional itself is oblivious to it. |
| using _Stored_type = remove_const_t<_Tp>; |
| |
| public: |
| // [X.Y.4.1] Constructors. |
| |
| // Constructors for disengaged optionals. |
| constexpr _Optional_base() noexcept |
| : _M_empty{} { } |
| |
| constexpr _Optional_base(nullopt_t) noexcept |
| : _Optional_base{} { } |
| |
| // Constructors for engaged optionals. |
| template<typename... _Args> |
| constexpr explicit _Optional_base(in_place_t, _Args&&... __args) |
| : _M_payload(std::forward<_Args>(__args)...), _M_engaged(true) { } |
| |
| template<typename _Up, typename... _Args, |
| enable_if_t<is_constructible<_Tp, |
| initializer_list<_Up>&, |
| _Args&&...>::value, |
| int>...> |
| constexpr explicit _Optional_base(in_place_t, |
| initializer_list<_Up> __il, |
| _Args&&... __args) |
| : _M_payload(__il, std::forward<_Args>(__args)...), |
| _M_engaged(true) { } |
| |
| // Copy and move constructors. |
| _Optional_base(const _Optional_base& __other) |
| { |
| if (__other._M_engaged) |
| this->_M_construct(__other._M_get()); |
| } |
| |
| _Optional_base(_Optional_base&& __other) |
| noexcept(is_nothrow_move_constructible<_Tp>()) |
| { |
| if (__other._M_engaged) |
| this->_M_construct(std::move(__other._M_get())); |
| } |
| |
| // [X.Y.4.3] (partly) Assignment. |
| _Optional_base& |
| operator=(const _Optional_base& __other) |
| { |
| if (this->_M_engaged && __other._M_engaged) |
| this->_M_get() = __other._M_get(); |
| else |
| { |
| if (__other._M_engaged) |
| this->_M_construct(__other._M_get()); |
| else |
| this->_M_reset(); |
| } |
| |
| return *this; |
| } |
| |
| _Optional_base& |
| operator=(_Optional_base&& __other) |
| noexcept(__and_<is_nothrow_move_constructible<_Tp>, |
| is_nothrow_move_assignable<_Tp>>()) |
| { |
| if (this->_M_engaged && __other._M_engaged) |
| this->_M_get() = std::move(__other._M_get()); |
| else |
| { |
| if (__other._M_engaged) |
| this->_M_construct(std::move(__other._M_get())); |
| else |
| this->_M_reset(); |
| } |
| return *this; |
| } |
| |
| // [X.Y.4.2] Destructor. |
| ~_Optional_base() |
| { |
| if (this->_M_engaged) |
| this->_M_payload.~_Stored_type(); |
| } |
| |
| // The following functionality is also needed by optional, hence the |
| // protected accessibility. |
| protected: |
| constexpr bool _M_is_engaged() const noexcept |
| { return this->_M_engaged; } |
| |
| // The _M_get operations have _M_engaged as a precondition. |
| constexpr _Tp& |
| _M_get() noexcept |
| { return _M_payload; } |
| |
| constexpr const _Tp& |
| _M_get() const noexcept |
| { return _M_payload; } |
| |
| // The _M_construct operation has !_M_engaged as a precondition |
| // while _M_destruct has _M_engaged as a precondition. |
| template<typename... _Args> |
| void |
| _M_construct(_Args&&... __args) |
| noexcept(is_nothrow_constructible<_Stored_type, _Args...>()) |
| { |
| ::new (std::__addressof(this->_M_payload)) |
| _Stored_type(std::forward<_Args>(__args)...); |
| this->_M_engaged = true; |
| } |
| |
| void |
| _M_destruct() |
| { |
| this->_M_engaged = false; |
| this->_M_payload.~_Stored_type(); |
| } |
| |
| // _M_reset is a 'safe' operation with no precondition. |
| void |
| _M_reset() |
| { |
| if (this->_M_engaged) |
| this->_M_destruct(); |
| } |
| |
| private: |
| struct _Empty_byte { }; |
| union { |
| _Empty_byte _M_empty; |
| _Stored_type _M_payload; |
| }; |
| bool _M_engaged = false; |
| }; |
| |
| /// Partial specialization that is exactly identical to the primary template |
| /// save for not providing a destructor, to fulfill triviality requirements. |
| template<typename _Tp> |
| class _Optional_base<_Tp, false> |
| { |
| private: |
| using _Stored_type = remove_const_t<_Tp>; |
| |
| public: |
| constexpr _Optional_base() noexcept |
| : _M_empty{} { } |
| |
| constexpr _Optional_base(nullopt_t) noexcept |
| : _Optional_base{} { } |
| |
| template<typename... _Args> |
| constexpr explicit _Optional_base(in_place_t, _Args&&... __args) |
| : _M_payload(std::forward<_Args>(__args)...), _M_engaged(true) { } |
| |
| template<typename _Up, typename... _Args, |
| enable_if_t<is_constructible<_Tp, |
| initializer_list<_Up>&, |
| _Args&&...>::value, |
| int>...> |
| constexpr explicit _Optional_base(in_place_t, |
| initializer_list<_Up> __il, |
| _Args&&... __args) |
| : _M_payload(__il, std::forward<_Args>(__args)...), |
| _M_engaged(true) { } |
| |
| _Optional_base(const _Optional_base& __other) |
| { |
| if (__other._M_engaged) |
| this->_M_construct(__other._M_get()); |
| } |
| |
| _Optional_base(_Optional_base&& __other) |
| noexcept(is_nothrow_move_constructible<_Tp>()) |
| { |
| if (__other._M_engaged) |
| this->_M_construct(std::move(__other._M_get())); |
| } |
| |
| _Optional_base& |
| operator=(const _Optional_base& __other) |
| { |
| if (this->_M_engaged && __other._M_engaged) |
| this->_M_get() = __other._M_get(); |
| else |
| { |
| if (__other._M_engaged) |
| this->_M_construct(__other._M_get()); |
| else |
| this->_M_reset(); |
| } |
| return *this; |
| } |
| |
| _Optional_base& |
| operator=(_Optional_base&& __other) |
| noexcept(__and_<is_nothrow_move_constructible<_Tp>, |
| is_nothrow_move_assignable<_Tp>>()) |
| { |
| if (this->_M_engaged && __other._M_engaged) |
| this->_M_get() = std::move(__other._M_get()); |
| else |
| { |
| if (__other._M_engaged) |
| this->_M_construct(std::move(__other._M_get())); |
| else |
| this->_M_reset(); |
| } |
| return *this; |
| } |
| |
| // Sole difference |
| // ~_Optional_base() noexcept = default; |
| |
| protected: |
| constexpr bool _M_is_engaged() const noexcept |
| { return this->_M_engaged; } |
| |
| _Tp& |
| _M_get() noexcept |
| { return _M_payload; } |
| |
| constexpr const _Tp& |
| _M_get() const noexcept |
| { return _M_payload; } |
| |
| template<typename... _Args> |
| void |
| _M_construct(_Args&&... __args) |
| noexcept(is_nothrow_constructible<_Stored_type, _Args...>()) |
| { |
| ::new (std::__addressof(this->_M_payload)) |
| _Stored_type(std::forward<_Args>(__args)...); |
| this->_M_engaged = true; |
| } |
| |
| void |
| _M_destruct() |
| { |
| this->_M_engaged = false; |
| this->_M_payload.~_Stored_type(); |
| } |
| |
| void |
| _M_reset() |
| { |
| if (this->_M_engaged) |
| this->_M_destruct(); |
| } |
| |
| private: |
| struct _Empty_byte { }; |
| union |
| { |
| _Empty_byte _M_empty; |
| _Stored_type _M_payload; |
| }; |
| bool _M_engaged = false; |
| }; |
| |
| template<typename _Tp, typename _Up> |
| using __converts_from_optional = |
| __or_<is_constructible<_Tp, const optional<_Up>&>, |
| is_constructible<_Tp, optional<_Up>&>, |
| is_constructible<_Tp, const optional<_Up>&&>, |
| is_constructible<_Tp, optional<_Up>&&>, |
| is_convertible<const optional<_Up>&, _Tp>, |
| is_convertible<optional<_Up>&, _Tp>, |
| is_convertible<const optional<_Up>&&, _Tp>, |
| is_convertible<optional<_Up>&&, _Tp>>; |
| |
| template<typename _Tp, typename _Up> |
| using __assigns_from_optional = |
| __or_<is_assignable<_Tp&, const optional<_Up>&>, |
| is_assignable<_Tp&, optional<_Up>&>, |
| is_assignable<_Tp&, const optional<_Up>&&>, |
| is_assignable<_Tp&, optional<_Up>&&>>; |
| |
| /// @endcond |
| |
| /** |
| * @brief Class template for optional values. |
| */ |
| template<typename _Tp> |
| class optional |
| : private _Optional_base<_Tp>, |
| private _Enable_copy_move< |
| // Copy constructor. |
| is_copy_constructible<_Tp>::value, |
| // Copy assignment. |
| __and_<is_copy_constructible<_Tp>, is_copy_assignable<_Tp>>::value, |
| // Move constructor. |
| is_move_constructible<_Tp>::value, |
| // Move assignment. |
| __and_<is_move_constructible<_Tp>, is_move_assignable<_Tp>>::value, |
| // Unique tag type. |
| optional<_Tp>> |
| { |
| static_assert(__and_<__not_<is_same<remove_cv_t<_Tp>, nullopt_t>>, |
| __not_<is_same<remove_cv_t<_Tp>, in_place_t>>, |
| __not_<is_reference<_Tp>>>(), |
| "Invalid instantiation of optional<T>"); |
| |
| private: |
| using _Base = _Optional_base<_Tp>; |
| |
| public: |
| using value_type = _Tp; |
| |
| // _Optional_base has the responsibility for construction. |
| using _Base::_Base; |
| |
| constexpr optional() = default; |
| // Converting constructors for engaged optionals. |
| template <typename _Up = _Tp, |
| enable_if_t<__and_< |
| __not_<is_same<optional<_Tp>, decay_t<_Up>>>, |
| is_constructible<_Tp, _Up&&>, |
| is_convertible<_Up&&, _Tp> |
| >::value, bool> = true> |
| constexpr optional(_Up&& __t) |
| : _Base(in_place, std::forward<_Up>(__t)) { } |
| |
| template <typename _Up = _Tp, |
| enable_if_t<__and_< |
| __not_<is_same<optional<_Tp>, decay_t<_Up>>>, |
| is_constructible<_Tp, _Up&&>, |
| __not_<is_convertible<_Up&&, _Tp>> |
| >::value, bool> = false> |
| explicit constexpr optional(_Up&& __t) |
| : _Base(in_place, std::forward<_Up>(__t)) { } |
| |
| template <typename _Up, |
| enable_if_t<__and_< |
| __not_<is_same<_Tp, _Up>>, |
| is_constructible<_Tp, const _Up&>, |
| is_convertible<const _Up&, _Tp>, |
| __not_<__converts_from_optional<_Tp, _Up>> |
| >::value, bool> = true> |
| constexpr optional(const optional<_Up>& __t) |
| { |
| if (__t) |
| emplace(*__t); |
| } |
| |
| template <typename _Up, |
| enable_if_t<__and_< |
| __not_<is_same<_Tp, _Up>>, |
| is_constructible<_Tp, const _Up&>, |
| __not_<is_convertible<const _Up&, _Tp>>, |
| __not_<__converts_from_optional<_Tp, _Up>> |
| >::value, bool> = false> |
| explicit constexpr optional(const optional<_Up>& __t) |
| { |
| if (__t) |
| emplace(*__t); |
| } |
| |
| template <typename _Up, |
| enable_if_t<__and_< |
| __not_<is_same<_Tp, _Up>>, |
| is_constructible<_Tp, _Up&&>, |
| is_convertible<_Up&&, _Tp>, |
| __not_<__converts_from_optional<_Tp, _Up>> |
| >::value, bool> = true> |
| constexpr optional(optional<_Up>&& __t) |
| { |
| if (__t) |
| emplace(std::move(*__t)); |
| } |
| |
| template <typename _Up, |
| enable_if_t<__and_< |
| __not_<is_same<_Tp, _Up>>, |
| is_constructible<_Tp, _Up&&>, |
| __not_<is_convertible<_Up&&, _Tp>>, |
| __not_<__converts_from_optional<_Tp, _Up>> |
| >::value, bool> = false> |
| explicit constexpr optional(optional<_Up>&& __t) |
| { |
| if (__t) |
| emplace(std::move(*__t)); |
| } |
| |
| // [X.Y.4.3] (partly) Assignment. |
| optional& |
| operator=(nullopt_t) noexcept |
| { |
| this->_M_reset(); |
| return *this; |
| } |
| |
| template<typename _Up = _Tp> |
| enable_if_t<__and_< |
| __not_<is_same<optional<_Tp>, decay_t<_Up>>>, |
| is_constructible<_Tp, _Up>, |
| __not_<__and_<is_scalar<_Tp>, |
| is_same<_Tp, decay_t<_Up>>>>, |
| is_assignable<_Tp&, _Up>>::value, |
| optional&> |
| operator=(_Up&& __u) |
| { |
| if (this->_M_is_engaged()) |
| this->_M_get() = std::forward<_Up>(__u); |
| else |
| this->_M_construct(std::forward<_Up>(__u)); |
| |
| return *this; |
| } |
| |
| template<typename _Up> |
| enable_if_t<__and_< |
| __not_<is_same<_Tp, _Up>>, |
| is_constructible<_Tp, const _Up&>, |
| is_assignable<_Tp&, _Up>, |
| __not_<__converts_from_optional<_Tp, _Up>>, |
| __not_<__assigns_from_optional<_Tp, _Up>> |
| >::value, |
| optional&> |
| operator=(const optional<_Up>& __u) |
| { |
| 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>>, |
| is_constructible<_Tp, _Up>, |
| is_assignable<_Tp&, _Up>, |
| __not_<__converts_from_optional<_Tp, _Up>>, |
| __not_<__assigns_from_optional<_Tp, _Up>> |
| >::value, |
| optional&> |
| operator=(optional<_Up>&& __u) |
| { |
| 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> |
| enable_if_t<is_constructible<_Tp, _Args&&...>::value> |
| emplace(_Args&&... __args) |
| { |
| this->_M_reset(); |
| this->_M_construct(std::forward<_Args>(__args)...); |
| } |
| |
| template<typename _Up, typename... _Args> |
| enable_if_t<is_constructible<_Tp, initializer_list<_Up>&, |
| _Args&&...>::value> |
| emplace(initializer_list<_Up> __il, _Args&&... __args) |
| { |
| this->_M_reset(); |
| this->_M_construct(__il, std::forward<_Args>(__args)...); |
| } |
| |
| // [X.Y.4.2] Destructor is implicit, implemented in _Optional_base. |
| |
| // [X.Y.4.4] Swap. |
| void |
| swap(optional& __other) |
| noexcept(is_nothrow_move_constructible<_Tp>() |
| && __is_nothrow_swappable<_Tp>::value) |
| { |
| using std::swap; |
| |
| if (this->_M_is_engaged() && __other._M_is_engaged()) |
| swap(this->_M_get(), __other._M_get()); |
| else if (this->_M_is_engaged()) |
| { |
| __other._M_construct(std::move(this->_M_get())); |
| this->_M_destruct(); |
| } |
| else if (__other._M_is_engaged()) |
| { |
| this->_M_construct(std::move(__other._M_get())); |
| __other._M_destruct(); |
| } |
| } |
| |
| // [X.Y.4.5] Observers. |
| constexpr const _Tp* |
| operator->() const |
| { return std::__addressof(this->_M_get()); } |
| |
| _Tp* |
| operator->() |
| { return std::__addressof(this->_M_get()); } |
| |
| constexpr const _Tp& |
| operator*() const& |
| { return this->_M_get(); } |
| |
| constexpr _Tp& |
| operator*()& |
| { return this->_M_get(); } |
| |
| constexpr _Tp&& |
| operator*()&& |
| { return std::move(this->_M_get()); } |
| |
| constexpr const _Tp&& |
| operator*() const&& |
| { return std::move(this->_M_get()); } |
| |
| constexpr explicit operator bool() const noexcept |
| { return this->_M_is_engaged(); } |
| |
| constexpr const _Tp& |
| value() const& |
| { |
| if (this->_M_is_engaged()) |
| return this->_M_get(); |
| __throw_bad_optional_access("Attempt to access value of a " |
| "disengaged optional object"); |
| } |
| |
| constexpr _Tp& |
| value()& |
| { |
| if (this->_M_is_engaged()) |
| return this->_M_get(); |
| __throw_bad_optional_access("Attempt to access value of a " |
| "disengaged optional object"); |
| } |
| |
| constexpr _Tp&& |
| value()&& |
| { |
| if (this->_M_is_engaged()) |
| return std::move(this->_M_get()); |
| __throw_bad_optional_access("Attempt to access value of a " |
| "disengaged optional object"); |
| } |
| |
| constexpr const _Tp&& |
| value() const&& |
| { |
| if (this->_M_is_engaged()) |
| return std::move(this->_M_get()); |
| __throw_bad_optional_access("Attempt to access value of a " |
| "disengaged optional object"); |
| } |
| |
| template<typename _Up> |
| constexpr _Tp |
| value_or(_Up&& __u) const& |
| { |
| static_assert(__and_<is_copy_constructible<_Tp>, |
| is_convertible<_Up&&, _Tp>>(), |
| "Cannot return value"); |
| |
| if (this->_M_is_engaged()) |
| return this->_M_get(); |
| else |
| return static_cast<_Tp>(std::forward<_Up>(__u)); |
| } |
| |
| template<typename _Up> |
| _Tp |
| value_or(_Up&& __u) && |
| { |
| static_assert(__and_<is_move_constructible<_Tp>, |
| is_convertible<_Up&&, _Tp>>(), |
| "Cannot return value" ); |
| |
| if (this->_M_is_engaged()) |
| return std::move(this->_M_get()); |
| else |
| return static_cast<_Tp>(std::forward<_Up>(__u)); |
| } |
| }; |
| |
| /// @relates experimental::optional @{ |
| |
| // [X.Y.8] Comparisons between optional values. |
| template<typename _Tp> |
| constexpr bool |
| operator==(const optional<_Tp>& __lhs, const optional<_Tp>& __rhs) |
| { |
| return static_cast<bool>(__lhs) == static_cast<bool>(__rhs) |
| && (!__lhs || *__lhs == *__rhs); |
| } |
| |
| template<typename _Tp> |
| constexpr bool |
| operator!=(const optional<_Tp>& __lhs, const optional<_Tp>& __rhs) |
| { return !(__lhs == __rhs); } |
| |
| template<typename _Tp> |
| constexpr bool |
| operator<(const optional<_Tp>& __lhs, const optional<_Tp>& __rhs) |
| { |
| return static_cast<bool>(__rhs) && (!__lhs || *__lhs < *__rhs); |
| } |
| |
| template<typename _Tp> |
| constexpr bool |
| operator>(const optional<_Tp>& __lhs, const optional<_Tp>& __rhs) |
| { return __rhs < __lhs; } |
| |
| template<typename _Tp> |
| constexpr bool |
| operator<=(const optional<_Tp>& __lhs, const optional<_Tp>& __rhs) |
| { return !(__rhs < __lhs); } |
| |
| template<typename _Tp> |
| constexpr bool |
| operator>=(const optional<_Tp>& __lhs, const optional<_Tp>& __rhs) |
| { return !(__lhs < __rhs); } |
| |
| // [X.Y.9] Comparisons with nullopt. |
| template<typename _Tp> |
| constexpr bool |
| operator==(const optional<_Tp>& __lhs, nullopt_t) noexcept |
| { return !__lhs; } |
| |
| template<typename _Tp> |
| constexpr bool |
| operator==(nullopt_t, const optional<_Tp>& __rhs) noexcept |
| { return !__rhs; } |
| |
| template<typename _Tp> |
| constexpr bool |
| operator!=(const optional<_Tp>& __lhs, nullopt_t) noexcept |
| { return static_cast<bool>(__lhs); } |
| |
| template<typename _Tp> |
| constexpr bool |
| operator!=(nullopt_t, const optional<_Tp>& __rhs) noexcept |
| { return static_cast<bool>(__rhs); } |
| |
| template<typename _Tp> |
| constexpr bool |
| operator<(const optional<_Tp>& /* __lhs */, nullopt_t) noexcept |
| { return false; } |
| |
| template<typename _Tp> |
| constexpr bool |
| operator<(nullopt_t, const optional<_Tp>& __rhs) noexcept |
| { return static_cast<bool>(__rhs); } |
| |
| template<typename _Tp> |
| constexpr bool |
| operator>(const optional<_Tp>& __lhs, nullopt_t) noexcept |
| { return static_cast<bool>(__lhs); } |
| |
| template<typename _Tp> |
| constexpr bool |
| operator>(nullopt_t, const optional<_Tp>& /* __rhs */) noexcept |
| { return false; } |
| |
| template<typename _Tp> |
| constexpr bool |
| operator<=(const optional<_Tp>& __lhs, nullopt_t) noexcept |
| { return !__lhs; } |
| |
| template<typename _Tp> |
| constexpr bool |
| operator<=(nullopt_t, const optional<_Tp>& /* __rhs */) noexcept |
| { return true; } |
| |
| template<typename _Tp> |
| constexpr bool |
| operator>=(const optional<_Tp>& /* __lhs */, nullopt_t) noexcept |
| { return true; } |
| |
| template<typename _Tp> |
| constexpr bool |
| operator>=(nullopt_t, const optional<_Tp>& __rhs) noexcept |
| { return !__rhs; } |
| |
| // [X.Y.10] Comparisons with value type. |
| template<typename _Tp> |
| constexpr bool |
| operator==(const optional<_Tp>& __lhs, const _Tp& __rhs) |
| { return __lhs && *__lhs == __rhs; } |
| |
| template<typename _Tp> |
| constexpr bool |
| operator==(const _Tp& __lhs, const optional<_Tp>& __rhs) |
| { return __rhs && __lhs == *__rhs; } |
| |
| template<typename _Tp> |
| constexpr bool |
| operator!=(const optional<_Tp>& __lhs, _Tp const& __rhs) |
| { return !__lhs || !(*__lhs == __rhs); } |
| |
| template<typename _Tp> |
| constexpr bool |
| operator!=(const _Tp& __lhs, const optional<_Tp>& __rhs) |
| { return !__rhs || !(__lhs == *__rhs); } |
| |
| template<typename _Tp> |
| constexpr bool |
| operator<(const optional<_Tp>& __lhs, const _Tp& __rhs) |
| { return !__lhs || *__lhs < __rhs; } |
| |
| template<typename _Tp> |
| constexpr bool |
| operator<(const _Tp& __lhs, const optional<_Tp>& __rhs) |
| { return __rhs && __lhs < *__rhs; } |
| |
| template<typename _Tp> |
| constexpr bool |
| operator>(const optional<_Tp>& __lhs, const _Tp& __rhs) |
| { return __lhs && __rhs < *__lhs; } |
| |
| template<typename _Tp> |
| constexpr bool |
| operator>(const _Tp& __lhs, const optional<_Tp>& __rhs) |
| { return !__rhs || *__rhs < __lhs; } |
| |
| template<typename _Tp> |
| constexpr bool |
| operator<=(const optional<_Tp>& __lhs, const _Tp& __rhs) |
| { return !__lhs || !(__rhs < *__lhs); } |
| |
| template<typename _Tp> |
| constexpr bool |
| operator<=(const _Tp& __lhs, const optional<_Tp>& __rhs) |
| { return __rhs && !(*__rhs < __lhs); } |
| |
| template<typename _Tp> |
| constexpr bool |
| operator>=(const optional<_Tp>& __lhs, const _Tp& __rhs) |
| { return __lhs && !(*__lhs < __rhs); } |
| |
| template<typename _Tp> |
| constexpr bool |
| operator>=(const _Tp& __lhs, const optional<_Tp>& __rhs) |
| { return !__rhs || !(__lhs < *__rhs); } |
| |
| // [X.Y.11] |
| template<typename _Tp> |
| inline void |
| swap(optional<_Tp>& __lhs, optional<_Tp>& __rhs) |
| noexcept(noexcept(__lhs.swap(__rhs))) |
| { __lhs.swap(__rhs); } |
| |
| template<typename _Tp> |
| constexpr optional<decay_t<_Tp>> |
| make_optional(_Tp&& __t) |
| { return optional<decay_t<_Tp>> { std::forward<_Tp>(__t) }; } |
| |
| /// @} relates experimental::optional |
| /// @} group optional |
| } // namespace fundamentals_v1 |
| } // namespace experimental |
| |
| // [X.Y.12] |
| /// std::hash partial specialization for experimental::optional |
| /// @relates experimental::optional |
| template<typename _Tp> |
| struct hash<experimental::optional<_Tp>> |
| { |
| using result_type = size_t; |
| using argument_type = experimental::optional<_Tp>; |
| |
| size_t |
| operator()(const experimental::optional<_Tp>& __t) const |
| noexcept(noexcept(hash<_Tp> {}(*__t))) |
| { |
| // We pick an arbitrary hash for disengaged optionals which hopefully |
| // usual values of _Tp won't typically hash to. |
| constexpr size_t __magic_disengaged_hash = static_cast<size_t>(-3333); |
| return __t ? hash<_Tp> {}(*__t) : __magic_disengaged_hash; |
| } |
| }; |
| |
| _GLIBCXX_END_NAMESPACE_VERSION |
| } // namespace std |
| |
| #endif // C++14 |
| |
| #endif // _GLIBCXX_EXPERIMENTAL_OPTIONAL |