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// Concept-constrained comparison implementations -*- 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 bits/ranges_cmp.h |
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* This is an internal header file, included by other library headers. |
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* Do not attempt to use it directly. @headername{functional} |
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*/ |
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#ifndef _RANGES_CMP_H |
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#define _RANGES_CMP_H 1 |
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|
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#if __cplusplus > 201703L |
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# include <bits/move.h> |
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# include <concepts> |
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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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struct __is_transparent; // not defined |
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// Define std::identity here so that <iterator> and <ranges> |
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// don't need to include <bits/stl_function.h> to get it. |
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|
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/// [func.identity] The identity function. |
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struct identity |
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{ |
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template<typename _Tp> |
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[[nodiscard]] |
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constexpr _Tp&& |
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operator()(_Tp&& __t) const noexcept |
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{ return std::forward<_Tp>(__t); } |
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|
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using is_transparent = __is_transparent; |
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}; |
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|
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#ifdef __cpp_lib_concepts |
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// Define this here, included by all the headers that need to define it. |
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#define __cpp_lib_ranges 201911L |
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|
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namespace ranges |
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{ |
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namespace __detail |
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{ |
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// BUILTIN-PTR-CMP(T, <, U) |
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// This determines whether t < u results in a call to a built-in operator< |
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// comparing pointers. It doesn't work for function pointers (PR 93628). |
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template<typename _Tp, typename _Up> |
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concept __less_builtin_ptr_cmp |
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= requires (_Tp&& __t, _Up&& __u) { { __t < __u } -> same_as<bool>; } |
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&& convertible_to<_Tp, const volatile void*> |
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&& convertible_to<_Up, const volatile void*> |
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&& (! requires(_Tp&& __t, _Up&& __u) |
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{ operator<(std::forward<_Tp>(__t), std::forward<_Up>(__u)); } |
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&& ! requires(_Tp&& __t, _Up&& __u) |
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{ std::forward<_Tp>(__t).operator<(std::forward<_Up>(__u)); }); |
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} // namespace __detail |
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|
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// [range.cmp] Concept-constrained comparisons |
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|
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// _GLIBCXX_RESOLVE_LIB_DEFECTS |
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// 3530 BUILTIN-PTR-MEOW should not opt the type out of syntactic checks |
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|
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/// ranges::equal_to function object type. |
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struct equal_to |
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{ |
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template<typename _Tp, typename _Up> |
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requires equality_comparable_with<_Tp, _Up> |
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constexpr bool |
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operator()(_Tp&& __t, _Up&& __u) const |
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noexcept(noexcept(std::declval<_Tp>() == std::declval<_Up>())) |
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{ return std::forward<_Tp>(__t) == std::forward<_Up>(__u); } |
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|
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using is_transparent = __is_transparent; |
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}; |
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|
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/// ranges::not_equal_to function object type. |
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struct not_equal_to |
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{ |
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template<typename _Tp, typename _Up> |
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requires equality_comparable_with<_Tp, _Up> |
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constexpr bool |
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operator()(_Tp&& __t, _Up&& __u) const |
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noexcept(noexcept(std::declval<_Up>() == std::declval<_Tp>())) |
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{ return !equal_to{}(std::forward<_Tp>(__t), std::forward<_Up>(__u)); } |
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|
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using is_transparent = __is_transparent; |
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}; |
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|
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/// ranges::less function object type. |
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struct less |
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{ |
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template<typename _Tp, typename _Up> |
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requires totally_ordered_with<_Tp, _Up> |
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constexpr bool |
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operator()(_Tp&& __t, _Up&& __u) const |
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noexcept(noexcept(std::declval<_Tp>() < std::declval<_Up>())) |
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{ |
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if constexpr (__detail::__less_builtin_ptr_cmp<_Tp, _Up>) |
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{ |
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#ifdef __cpp_lib_is_constant_evaluated |
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if (std::is_constant_evaluated()) |
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return __t < __u; |
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#endif |
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auto __x = reinterpret_cast<__UINTPTR_TYPE__>( |
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static_cast<const volatile void*>(std::forward<_Tp>(__t))); |
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auto __y = reinterpret_cast<__UINTPTR_TYPE__>( |
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static_cast<const volatile void*>(std::forward<_Up>(__u))); |
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return __x < __y; |
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} |
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else |
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return std::forward<_Tp>(__t) < std::forward<_Up>(__u); |
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} |
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|
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using is_transparent = __is_transparent; |
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}; |
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|
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/// ranges::greater function object type. |
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struct greater |
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{ |
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template<typename _Tp, typename _Up> |
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requires totally_ordered_with<_Tp, _Up> |
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constexpr bool |
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operator()(_Tp&& __t, _Up&& __u) const |
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noexcept(noexcept(std::declval<_Up>() < std::declval<_Tp>())) |
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{ return less{}(std::forward<_Up>(__u), std::forward<_Tp>(__t)); } |
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|
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using is_transparent = __is_transparent; |
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}; |
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/// ranges::greater_equal function object type. |
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struct greater_equal |
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{ |
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template<typename _Tp, typename _Up> |
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requires totally_ordered_with<_Tp, _Up> |
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constexpr bool |
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operator()(_Tp&& __t, _Up&& __u) const |
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noexcept(noexcept(std::declval<_Tp>() < std::declval<_Up>())) |
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{ return !less{}(std::forward<_Tp>(__t), std::forward<_Up>(__u)); } |
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|
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using is_transparent = __is_transparent; |
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}; |
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/// ranges::less_equal function object type. |
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struct less_equal |
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{ |
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template<typename _Tp, typename _Up> |
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requires totally_ordered_with<_Tp, _Up> |
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constexpr bool |
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operator()(_Tp&& __t, _Up&& __u) const |
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noexcept(noexcept(std::declval<_Up>() < std::declval<_Tp>())) |
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{ return !less{}(std::forward<_Up>(__u), std::forward<_Tp>(__t)); } |
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|
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using is_transparent = __is_transparent; |
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}; |
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|
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} // namespace ranges |
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#endif // library concepts |
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_GLIBCXX_END_NAMESPACE_VERSION |
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} // namespace std |
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#endif // C++20 |
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#endif // _RANGES_CMP_H |
