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// <concepts> -*- C++ -*- |
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// Copyright (C) 2019-2021 Free Software Foundation, Inc. |
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// |
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// This file is part of the GNU ISO C++ Library. This library is free |
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// software; you can redistribute it and/or modify it under the |
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// terms of the GNU General Public License as published by the |
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// Free Software Foundation; either version 3, or (at your option) |
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// any later version. |
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|
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// This library is distributed in the hope that it will be useful, |
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// but WITHOUT ANY WARRANTY; without even the implied warranty of |
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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// GNU General Public License for more details. |
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|
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// Under Section 7 of GPL version 3, you are granted additional |
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// permissions described in the GCC Runtime Library Exception, version |
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// 3.1, as published by the Free Software Foundation. |
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|
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// You should have received a copy of the GNU General Public License and |
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// a copy of the GCC Runtime Library Exception along with this program; |
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// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
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// <http://www.gnu.org/licenses/>. |
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|
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/** @file include/concepts |
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* This is a Standard C++ Library header. |
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* @ingroup concepts |
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*/ |
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|
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#ifndef _GLIBCXX_CONCEPTS |
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#define _GLIBCXX_CONCEPTS 1 |
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|
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#if __cplusplus > 201703L && __cpp_concepts >= 201907L |
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|
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#pragma GCC system_header |
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|
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/** |
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* @defgroup concepts Concepts |
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* @ingroup utilities |
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* |
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* Concepts for checking type requirements. |
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*/ |
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#include <type_traits> |
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|
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namespace std _GLIBCXX_VISIBILITY(default) |
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{ |
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_GLIBCXX_BEGIN_NAMESPACE_VERSION |
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|
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#define __cpp_lib_concepts 202002L |
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|
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// [concepts.lang], language-related concepts |
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|
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namespace __detail |
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{ |
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template<typename _Tp, typename _Up> |
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concept __same_as = std::is_same_v<_Tp, _Up>; |
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} // namespace __detail |
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|
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/// [concept.same], concept same_as |
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template<typename _Tp, typename _Up> |
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concept same_as |
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= __detail::__same_as<_Tp, _Up> && __detail::__same_as<_Up, _Tp>; |
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|
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/// [concept.derived], concept derived_from |
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template<typename _Derived, typename _Base> |
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concept derived_from = __is_base_of(_Base, _Derived) |
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&& is_convertible_v<const volatile _Derived*, const volatile _Base*>; |
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|
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/// [concept.convertible], concept convertible_to |
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template<typename _From, typename _To> |
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concept convertible_to = is_convertible_v<_From, _To> |
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&& requires(add_rvalue_reference_t<_From> (&__f)()) { |
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static_cast<_To>(__f()); |
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}; |
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|
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/// [concept.commonref], concept common_reference_with |
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template<typename _Tp, typename _Up> |
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concept common_reference_with |
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= same_as<common_reference_t<_Tp, _Up>, common_reference_t<_Up, _Tp>> |
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&& convertible_to<_Tp, common_reference_t<_Tp, _Up>> |
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&& convertible_to<_Up, common_reference_t<_Tp, _Up>>; |
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|
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/// [concept.common], concept common_with |
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template<typename _Tp, typename _Up> |
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concept common_with |
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= same_as<common_type_t<_Tp, _Up>, common_type_t<_Up, _Tp>> |
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&& requires { |
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static_cast<common_type_t<_Tp, _Up>>(std::declval<_Tp>()); |
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static_cast<common_type_t<_Tp, _Up>>(std::declval<_Up>()); |
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} |
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&& common_reference_with<add_lvalue_reference_t<const _Tp>, |
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add_lvalue_reference_t<const _Up>> |
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&& common_reference_with<add_lvalue_reference_t<common_type_t<_Tp, _Up>>, |
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common_reference_t< |
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add_lvalue_reference_t<const _Tp>, |
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add_lvalue_reference_t<const _Up>>>; |
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|
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// [concepts.arithmetic], arithmetic concepts |
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|
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template<typename _Tp> |
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concept integral = is_integral_v<_Tp>; |
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|
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template<typename _Tp> |
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concept signed_integral = integral<_Tp> && is_signed_v<_Tp>; |
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|
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template<typename _Tp> |
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concept unsigned_integral = integral<_Tp> && !signed_integral<_Tp>; |
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|
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template<typename _Tp> |
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concept floating_point = is_floating_point_v<_Tp>; |
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|
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namespace __detail |
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{ |
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template<typename _Tp> |
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using __cref = const remove_reference_t<_Tp>&; |
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|
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template<typename _Tp> |
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concept __class_or_enum |
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= is_class_v<_Tp> || is_union_v<_Tp> || is_enum_v<_Tp>; |
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} // namespace __detail |
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/// [concept.assignable], concept assignable_from |
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template<typename _Lhs, typename _Rhs> |
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concept assignable_from |
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= is_lvalue_reference_v<_Lhs> |
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&& common_reference_with<__detail::__cref<_Lhs>, __detail::__cref<_Rhs>> |
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&& requires(_Lhs __lhs, _Rhs&& __rhs) { |
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{ __lhs = static_cast<_Rhs&&>(__rhs) } -> same_as<_Lhs>; |
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}; |
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|
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/// [concept.destructible], concept destructible |
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template<typename _Tp> |
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concept destructible = is_nothrow_destructible_v<_Tp>; |
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/// [concept.constructible], concept constructible_from |
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template<typename _Tp, typename... _Args> |
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concept constructible_from |
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= destructible<_Tp> && is_constructible_v<_Tp, _Args...>; |
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/// [concept.defaultinitializable], concept default_initializable |
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template<typename _Tp> |
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concept default_initializable = constructible_from<_Tp> |
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&& requires |
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{ |
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_Tp{}; |
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(void) ::new _Tp; |
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}; |
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/// [concept.moveconstructible], concept move_constructible |
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template<typename _Tp> |
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concept move_constructible |
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= constructible_from<_Tp, _Tp> && convertible_to<_Tp, _Tp>; |
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/// [concept.copyconstructible], concept copy_constructible |
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template<typename _Tp> |
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concept copy_constructible |
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= move_constructible<_Tp> |
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&& constructible_from<_Tp, _Tp&> && convertible_to<_Tp&, _Tp> |
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&& constructible_from<_Tp, const _Tp&> && convertible_to<const _Tp&, _Tp> |
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&& constructible_from<_Tp, const _Tp> && convertible_to<const _Tp, _Tp>; |
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// [concept.swappable], concept swappable |
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namespace ranges |
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{ |
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namespace __cust_swap |
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{ |
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template<typename _Tp> void swap(_Tp&, _Tp&) = delete; |
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template<typename _Tp, typename _Up> |
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concept __adl_swap |
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= (__detail::__class_or_enum<remove_reference_t<_Tp>> |
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|| __detail::__class_or_enum<remove_reference_t<_Up>>) |
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&& requires(_Tp&& __t, _Up&& __u) { |
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swap(static_cast<_Tp&&>(__t), static_cast<_Up&&>(__u)); |
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}; |
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struct _Swap |
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{ |
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private: |
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template<typename _Tp, typename _Up> |
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static constexpr bool |
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_S_noexcept() |
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{ |
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if constexpr (__adl_swap<_Tp, _Up>) |
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return noexcept(swap(std::declval<_Tp>(), std::declval<_Up>())); |
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else |
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return is_nothrow_move_constructible_v<remove_reference_t<_Tp>> |
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&& is_nothrow_move_assignable_v<remove_reference_t<_Tp>>; |
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} |
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public: |
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template<typename _Tp, typename _Up> |
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requires __adl_swap<_Tp, _Up> |
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|| (same_as<_Tp, _Up> && is_lvalue_reference_v<_Tp> |
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&& move_constructible<remove_reference_t<_Tp>> |
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&& assignable_from<_Tp, remove_reference_t<_Tp>>) |
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constexpr void |
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operator()(_Tp&& __t, _Up&& __u) const |
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noexcept(_S_noexcept<_Tp, _Up>()) |
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{ |
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if constexpr (__adl_swap<_Tp, _Up>) |
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swap(static_cast<_Tp&&>(__t), static_cast<_Up&&>(__u)); |
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else |
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{ |
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auto __tmp = static_cast<remove_reference_t<_Tp>&&>(__t); |
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__t = static_cast<remove_reference_t<_Tp>&&>(__u); |
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__u = static_cast<remove_reference_t<_Tp>&&>(__tmp); |
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} |
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} |
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template<typename _Tp, typename _Up, size_t _Num> |
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requires requires(const _Swap& __swap, _Tp& __e1, _Up& __e2) { |
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__swap(__e1, __e2); |
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} |
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constexpr void |
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operator()(_Tp (&__e1)[_Num], _Up (&__e2)[_Num]) const |
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noexcept(noexcept(std::declval<const _Swap&>()(*__e1, *__e2))) |
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{ |
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for (size_t __n = 0; __n < _Num; ++__n) |
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(*this)(__e1[__n], __e2[__n]); |
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} |
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}; |
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} // namespace __cust_swap |
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inline namespace __cust |
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{ |
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inline constexpr __cust_swap::_Swap swap{}; |
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} // inline namespace __cust |
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} // namespace ranges |
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template<typename _Tp> |
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concept swappable |
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= requires(_Tp& __a, _Tp& __b) { ranges::swap(__a, __b); }; |
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template<typename _Tp, typename _Up> |
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concept swappable_with = common_reference_with<_Tp, _Up> |
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&& requires(_Tp&& __t, _Up&& __u) { |
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ranges::swap(static_cast<_Tp&&>(__t), static_cast<_Tp&&>(__t)); |
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ranges::swap(static_cast<_Up&&>(__u), static_cast<_Up&&>(__u)); |
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ranges::swap(static_cast<_Tp&&>(__t), static_cast<_Up&&>(__u)); |
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ranges::swap(static_cast<_Up&&>(__u), static_cast<_Tp&&>(__t)); |
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}; |
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// [concepts.object], Object concepts |
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|
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template<typename _Tp> |
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concept movable = is_object_v<_Tp> && move_constructible<_Tp> |
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&& assignable_from<_Tp&, _Tp> && swappable<_Tp>; |
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template<typename _Tp> |
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concept copyable = copy_constructible<_Tp> && movable<_Tp> |
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&& assignable_from<_Tp&, _Tp&> && assignable_from<_Tp&, const _Tp&> |
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&& assignable_from<_Tp&, const _Tp>; |
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template<typename _Tp> |
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concept semiregular = copyable<_Tp> && default_initializable<_Tp>; |
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// [concepts.compare], comparison concepts |
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// [concept.booleantestable], Boolean testability |
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namespace __detail |
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{ |
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template<typename _Tp> |
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concept __boolean_testable_impl = convertible_to<_Tp, bool>; |
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|
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template<typename _Tp> |
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concept __boolean_testable |
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= __boolean_testable_impl<_Tp> |
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&& requires(_Tp&& __t) |
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{ { !static_cast<_Tp&&>(__t) } -> __boolean_testable_impl; }; |
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} // namespace __detail |
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// [concept.equalitycomparable], concept equality_comparable |
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namespace __detail |
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{ |
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template<typename _Tp, typename _Up> |
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concept __weakly_eq_cmp_with |
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= requires(__detail::__cref<_Tp> __t, __detail::__cref<_Up> __u) { |
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{ __t == __u } -> __boolean_testable; |
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{ __t != __u } -> __boolean_testable; |
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{ __u == __t } -> __boolean_testable; |
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{ __u != __t } -> __boolean_testable; |
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}; |
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} // namespace __detail |
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template<typename _Tp> |
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concept equality_comparable = __detail::__weakly_eq_cmp_with<_Tp, _Tp>; |
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|
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template<typename _Tp, typename _Up> |
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concept equality_comparable_with |
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= equality_comparable<_Tp> && equality_comparable<_Up> |
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&& common_reference_with<__detail::__cref<_Tp>, __detail::__cref<_Up>> |
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&& equality_comparable<common_reference_t<__detail::__cref<_Tp>, |
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__detail::__cref<_Up>>> |
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&& __detail::__weakly_eq_cmp_with<_Tp, _Up>; |
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|
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namespace __detail |
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{ |
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template<typename _Tp, typename _Up> |
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concept __partially_ordered_with |
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= requires(const remove_reference_t<_Tp>& __t, |
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const remove_reference_t<_Up>& __u) { |
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{ __t < __u } -> __boolean_testable; |
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{ __t > __u } -> __boolean_testable; |
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{ __t <= __u } -> __boolean_testable; |
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{ __t >= __u } -> __boolean_testable; |
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{ __u < __t } -> __boolean_testable; |
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{ __u > __t } -> __boolean_testable; |
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{ __u <= __t } -> __boolean_testable; |
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{ __u >= __t } -> __boolean_testable; |
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}; |
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} // namespace __detail |
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// [concept.totallyordered], concept totally_ordered |
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template<typename _Tp> |
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concept totally_ordered |
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= equality_comparable<_Tp> |
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&& __detail::__partially_ordered_with<_Tp, _Tp>; |
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|
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template<typename _Tp, typename _Up> |
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concept totally_ordered_with |
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= totally_ordered<_Tp> && totally_ordered<_Up> |
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&& equality_comparable_with<_Tp, _Up> |
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&& totally_ordered<common_reference_t<__detail::__cref<_Tp>, |
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__detail::__cref<_Up>>> |
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&& __detail::__partially_ordered_with<_Tp, _Up>; |
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|
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template<typename _Tp> |
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concept regular = semiregular<_Tp> && equality_comparable<_Tp>; |
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// [concepts.callable], callable concepts |
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/// [concept.invocable], concept invocable |
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template<typename _Fn, typename... _Args> |
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concept invocable = is_invocable_v<_Fn, _Args...>; |
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|
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/// [concept.regularinvocable], concept regular_invocable |
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template<typename _Fn, typename... _Args> |
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concept regular_invocable = invocable<_Fn, _Args...>; |
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|
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/// [concept.predicate], concept predicate |
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template<typename _Fn, typename... _Args> |
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concept predicate = regular_invocable<_Fn, _Args...> |
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&& __detail::__boolean_testable<invoke_result_t<_Fn, _Args...>>; |
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|
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/// [concept.relation], concept relation |
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template<typename _Rel, typename _Tp, typename _Up> |
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concept relation |
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= predicate<_Rel, _Tp, _Tp> && predicate<_Rel, _Up, _Up> |
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&& predicate<_Rel, _Tp, _Up> && predicate<_Rel, _Up, _Tp>; |
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|
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/// [concept.equiv], concept equivalence_relation |
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template<typename _Rel, typename _Tp, typename _Up> |
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concept equivalence_relation = relation<_Rel, _Tp, _Up>; |
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|
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/// [concept.strictweakorder], concept strict_weak_order |
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template<typename _Rel, typename _Tp, typename _Up> |
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concept strict_weak_order = relation<_Rel, _Tp, _Up>; |
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|
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_GLIBCXX_END_NAMESPACE_VERSION |
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} // namespace |
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#endif // C++2a |
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|
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#endif /* _GLIBCXX_CONCEPTS */ |
