| // <concepts> -*- C++ -*- |
| |
| // Copyright (C) 2019-2021 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 include/concepts |
| * This is a Standard C++ Library header. |
| * @ingroup concepts |
| */ |
| |
| #ifndef _GLIBCXX_CONCEPTS |
| #define _GLIBCXX_CONCEPTS 1 |
| |
| #if __cplusplus > 201703L && __cpp_concepts >= 201907L |
| |
| #pragma GCC system_header |
| |
| /** |
| * @defgroup concepts Concepts |
| * @ingroup utilities |
| * |
| * Concepts for checking type requirements. |
| */ |
| |
| #include <type_traits> |
| |
| namespace std _GLIBCXX_VISIBILITY(default) |
| { |
| _GLIBCXX_BEGIN_NAMESPACE_VERSION |
| |
| #define __cpp_lib_concepts 202002L |
| |
| // [concepts.lang], language-related concepts |
| |
| namespace __detail |
| { |
| template<typename _Tp, typename _Up> |
| concept __same_as = std::is_same_v<_Tp, _Up>; |
| } // namespace __detail |
| |
| /// [concept.same], concept same_as |
| template<typename _Tp, typename _Up> |
| concept same_as |
| = __detail::__same_as<_Tp, _Up> && __detail::__same_as<_Up, _Tp>; |
| |
| /// [concept.derived], concept derived_from |
| template<typename _Derived, typename _Base> |
| concept derived_from = __is_base_of(_Base, _Derived) |
| && is_convertible_v<const volatile _Derived*, const volatile _Base*>; |
| |
| /// [concept.convertible], concept convertible_to |
| template<typename _From, typename _To> |
| concept convertible_to = is_convertible_v<_From, _To> |
| && requires { static_cast<_To>(std::declval<_From>()); }; |
| |
| /// [concept.commonref], concept common_reference_with |
| template<typename _Tp, typename _Up> |
| concept common_reference_with |
| = same_as<common_reference_t<_Tp, _Up>, common_reference_t<_Up, _Tp>> |
| && convertible_to<_Tp, common_reference_t<_Tp, _Up>> |
| && convertible_to<_Up, common_reference_t<_Tp, _Up>>; |
| |
| /// [concept.common], concept common_with |
| template<typename _Tp, typename _Up> |
| concept common_with |
| = same_as<common_type_t<_Tp, _Up>, common_type_t<_Up, _Tp>> |
| && requires { |
| static_cast<common_type_t<_Tp, _Up>>(std::declval<_Tp>()); |
| static_cast<common_type_t<_Tp, _Up>>(std::declval<_Up>()); |
| } |
| && common_reference_with<add_lvalue_reference_t<const _Tp>, |
| add_lvalue_reference_t<const _Up>> |
| && common_reference_with<add_lvalue_reference_t<common_type_t<_Tp, _Up>>, |
| common_reference_t< |
| add_lvalue_reference_t<const _Tp>, |
| add_lvalue_reference_t<const _Up>>>; |
| |
| // [concepts.arithmetic], arithmetic concepts |
| |
| template<typename _Tp> |
| concept integral = is_integral_v<_Tp>; |
| |
| template<typename _Tp> |
| concept signed_integral = integral<_Tp> && is_signed_v<_Tp>; |
| |
| template<typename _Tp> |
| concept unsigned_integral = integral<_Tp> && !signed_integral<_Tp>; |
| |
| template<typename _Tp> |
| concept floating_point = is_floating_point_v<_Tp>; |
| |
| namespace __detail |
| { |
| template<typename _Tp> |
| using __cref = const remove_reference_t<_Tp>&; |
| |
| template<typename _Tp> |
| concept __class_or_enum |
| = is_class_v<_Tp> || is_union_v<_Tp> || is_enum_v<_Tp>; |
| } // namespace __detail |
| |
| /// [concept.assignable], concept assignable_from |
| template<typename _Lhs, typename _Rhs> |
| concept assignable_from |
| = is_lvalue_reference_v<_Lhs> |
| && common_reference_with<__detail::__cref<_Lhs>, __detail::__cref<_Rhs>> |
| && requires(_Lhs __lhs, _Rhs&& __rhs) { |
| { __lhs = static_cast<_Rhs&&>(__rhs) } -> same_as<_Lhs>; |
| }; |
| |
| /// [concept.destructible], concept destructible |
| template<typename _Tp> |
| concept destructible = is_nothrow_destructible_v<_Tp>; |
| |
| /// [concept.constructible], concept constructible_from |
| template<typename _Tp, typename... _Args> |
| concept constructible_from |
| = destructible<_Tp> && is_constructible_v<_Tp, _Args...>; |
| |
| /// [concept.defaultinitializable], concept default_initializable |
| template<typename _Tp> |
| concept default_initializable = constructible_from<_Tp> |
| && requires |
| { |
| _Tp{}; |
| (void) ::new _Tp; |
| }; |
| |
| /// [concept.moveconstructible], concept move_constructible |
| template<typename _Tp> |
| concept move_constructible |
| = constructible_from<_Tp, _Tp> && convertible_to<_Tp, _Tp>; |
| |
| /// [concept.copyconstructible], concept copy_constructible |
| template<typename _Tp> |
| concept copy_constructible |
| = move_constructible<_Tp> |
| && constructible_from<_Tp, _Tp&> && convertible_to<_Tp&, _Tp> |
| && constructible_from<_Tp, const _Tp&> && convertible_to<const _Tp&, _Tp> |
| && constructible_from<_Tp, const _Tp> && convertible_to<const _Tp, _Tp>; |
| |
| // [concept.swappable], concept swappable |
| |
| namespace ranges |
| { |
| namespace __cust_swap |
| { |
| template<typename _Tp> void swap(_Tp&, _Tp&) = delete; |
| |
| template<typename _Tp, typename _Up> |
| concept __adl_swap |
| = (__detail::__class_or_enum<remove_reference_t<_Tp>> |
| || __detail::__class_or_enum<remove_reference_t<_Up>>) |
| && requires(_Tp&& __t, _Up&& __u) { |
| swap(static_cast<_Tp&&>(__t), static_cast<_Up&&>(__u)); |
| }; |
| |
| struct _Swap |
| { |
| private: |
| template<typename _Tp, typename _Up> |
| static constexpr bool |
| _S_noexcept() |
| { |
| if constexpr (__adl_swap<_Tp, _Up>) |
| return noexcept(swap(std::declval<_Tp>(), std::declval<_Up>())); |
| else |
| return is_nothrow_move_constructible_v<remove_reference_t<_Tp>> |
| && is_nothrow_move_assignable_v<remove_reference_t<_Tp>>; |
| } |
| |
| public: |
| template<typename _Tp, typename _Up> |
| requires __adl_swap<_Tp, _Up> |
| || (same_as<_Tp, _Up> && is_lvalue_reference_v<_Tp> |
| && move_constructible<remove_reference_t<_Tp>> |
| && assignable_from<_Tp, remove_reference_t<_Tp>>) |
| constexpr void |
| operator()(_Tp&& __t, _Up&& __u) const |
| noexcept(_S_noexcept<_Tp, _Up>()) |
| { |
| if constexpr (__adl_swap<_Tp, _Up>) |
| swap(static_cast<_Tp&&>(__t), static_cast<_Up&&>(__u)); |
| else |
| { |
| auto __tmp = static_cast<remove_reference_t<_Tp>&&>(__t); |
| __t = static_cast<remove_reference_t<_Tp>&&>(__u); |
| __u = static_cast<remove_reference_t<_Tp>&&>(__tmp); |
| } |
| } |
| |
| template<typename _Tp, typename _Up, size_t _Num> |
| requires requires(const _Swap& __swap, _Tp& __e1, _Up& __e2) { |
| __swap(__e1, __e2); |
| } |
| constexpr void |
| operator()(_Tp (&__e1)[_Num], _Up (&__e2)[_Num]) const |
| noexcept(noexcept(std::declval<const _Swap&>()(*__e1, *__e2))) |
| { |
| for (size_t __n = 0; __n < _Num; ++__n) |
| (*this)(__e1[__n], __e2[__n]); |
| } |
| }; |
| } // namespace __cust_swap |
| |
| inline namespace __cust |
| { |
| inline constexpr __cust_swap::_Swap swap{}; |
| } // inline namespace __cust |
| } // namespace ranges |
| |
| template<typename _Tp> |
| concept swappable |
| = requires(_Tp& __a, _Tp& __b) { ranges::swap(__a, __b); }; |
| |
| template<typename _Tp, typename _Up> |
| concept swappable_with = common_reference_with<_Tp, _Up> |
| && requires(_Tp&& __t, _Up&& __u) { |
| ranges::swap(static_cast<_Tp&&>(__t), static_cast<_Tp&&>(__t)); |
| ranges::swap(static_cast<_Up&&>(__u), static_cast<_Up&&>(__u)); |
| ranges::swap(static_cast<_Tp&&>(__t), static_cast<_Up&&>(__u)); |
| ranges::swap(static_cast<_Up&&>(__u), static_cast<_Tp&&>(__t)); |
| }; |
| |
| // [concepts.object], Object concepts |
| |
| template<typename _Tp> |
| concept movable = is_object_v<_Tp> && move_constructible<_Tp> |
| && assignable_from<_Tp&, _Tp> && swappable<_Tp>; |
| |
| template<typename _Tp> |
| concept copyable = copy_constructible<_Tp> && movable<_Tp> |
| && assignable_from<_Tp&, _Tp&> && assignable_from<_Tp&, const _Tp&> |
| && assignable_from<_Tp&, const _Tp>; |
| |
| template<typename _Tp> |
| concept semiregular = copyable<_Tp> && default_initializable<_Tp>; |
| |
| // [concepts.compare], comparison concepts |
| |
| // [concept.booleantestable], Boolean testability |
| namespace __detail |
| { |
| template<typename _Tp> |
| concept __boolean_testable_impl = convertible_to<_Tp, bool>; |
| |
| template<typename _Tp> |
| concept __boolean_testable |
| = __boolean_testable_impl<_Tp> |
| && requires(_Tp&& __t) |
| { { !static_cast<_Tp&&>(__t) } -> __boolean_testable_impl; }; |
| } // namespace __detail |
| |
| // [concept.equalitycomparable], concept equality_comparable |
| |
| namespace __detail |
| { |
| template<typename _Tp, typename _Up> |
| concept __weakly_eq_cmp_with |
| = requires(__detail::__cref<_Tp> __t, __detail::__cref<_Up> __u) { |
| { __t == __u } -> __boolean_testable; |
| { __t != __u } -> __boolean_testable; |
| { __u == __t } -> __boolean_testable; |
| { __u != __t } -> __boolean_testable; |
| }; |
| } // namespace __detail |
| |
| template<typename _Tp> |
| concept equality_comparable = __detail::__weakly_eq_cmp_with<_Tp, _Tp>; |
| |
| template<typename _Tp, typename _Up> |
| concept equality_comparable_with |
| = equality_comparable<_Tp> && equality_comparable<_Up> |
| && common_reference_with<__detail::__cref<_Tp>, __detail::__cref<_Up>> |
| && equality_comparable<common_reference_t<__detail::__cref<_Tp>, |
| __detail::__cref<_Up>>> |
| && __detail::__weakly_eq_cmp_with<_Tp, _Up>; |
| |
| namespace __detail |
| { |
| template<typename _Tp, typename _Up> |
| concept __partially_ordered_with |
| = requires(const remove_reference_t<_Tp>& __t, |
| const remove_reference_t<_Up>& __u) { |
| { __t < __u } -> __boolean_testable; |
| { __t > __u } -> __boolean_testable; |
| { __t <= __u } -> __boolean_testable; |
| { __t >= __u } -> __boolean_testable; |
| { __u < __t } -> __boolean_testable; |
| { __u > __t } -> __boolean_testable; |
| { __u <= __t } -> __boolean_testable; |
| { __u >= __t } -> __boolean_testable; |
| }; |
| } // namespace __detail |
| |
| // [concept.totallyordered], concept totally_ordered |
| template<typename _Tp> |
| concept totally_ordered |
| = equality_comparable<_Tp> |
| && __detail::__partially_ordered_with<_Tp, _Tp>; |
| |
| template<typename _Tp, typename _Up> |
| concept totally_ordered_with |
| = totally_ordered<_Tp> && totally_ordered<_Up> |
| && equality_comparable_with<_Tp, _Up> |
| && totally_ordered<common_reference_t<__detail::__cref<_Tp>, |
| __detail::__cref<_Up>>> |
| && __detail::__partially_ordered_with<_Tp, _Up>; |
| |
| template<typename _Tp> |
| concept regular = semiregular<_Tp> && equality_comparable<_Tp>; |
| |
| // [concepts.callable], callable concepts |
| |
| /// [concept.invocable], concept invocable |
| template<typename _Fn, typename... _Args> |
| concept invocable = is_invocable_v<_Fn, _Args...>; |
| |
| /// [concept.regularinvocable], concept regular_invocable |
| template<typename _Fn, typename... _Args> |
| concept regular_invocable = invocable<_Fn, _Args...>; |
| |
| /// [concept.predicate], concept predicate |
| template<typename _Fn, typename... _Args> |
| concept predicate = regular_invocable<_Fn, _Args...> |
| && __detail::__boolean_testable<invoke_result_t<_Fn, _Args...>>; |
| |
| /// [concept.relation], concept relation |
| template<typename _Rel, typename _Tp, typename _Up> |
| concept relation |
| = predicate<_Rel, _Tp, _Tp> && predicate<_Rel, _Up, _Up> |
| && predicate<_Rel, _Tp, _Up> && predicate<_Rel, _Up, _Tp>; |
| |
| /// [concept.equiv], concept equivalence_relation |
| template<typename _Rel, typename _Tp, typename _Up> |
| concept equivalence_relation = relation<_Rel, _Tp, _Up>; |
| |
| /// [concept.strictweakorder], concept strict_weak_order |
| template<typename _Rel, typename _Tp, typename _Up> |
| concept strict_weak_order = relation<_Rel, _Tp, _Up>; |
| |
| _GLIBCXX_END_NAMESPACE_VERSION |
| } // namespace |
| #endif // C++2a |
| |
| #endif /* _GLIBCXX_CONCEPTS */ |