1 //===----------------------------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #ifndef _LIBCPP___COMPARE_THREE_WAY_COMPARABLE_H 10 #define _LIBCPP___COMPARE_THREE_WAY_COMPARABLE_H 11 12 #include <__compare/common_comparison_category.h> 13 #include <__compare/ordering.h> 14 #include <__concepts/common_reference_with.h> 15 #include <__concepts/equality_comparable.h> 16 #include <__concepts/same_as.h> 17 #include <__concepts/totally_ordered.h> 18 #include <__config> 19 #include <__type_traits/common_reference.h> 20 #include <__type_traits/make_const_lvalue_ref.h> 21 22 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 23 # pragma GCC system_header 24 #endif 25 26 _LIBCPP_BEGIN_NAMESPACE_STD 27 28 #if _LIBCPP_STD_VER >= 20 29 30 template <class _Tp, class _Cat> 31 concept __compares_as = same_as<common_comparison_category_t<_Tp, _Cat>, _Cat>; 32 33 template <class _Tp, class _Cat = partial_ordering> 34 concept three_way_comparable = 35 __weakly_equality_comparable_with<_Tp, _Tp> && __partially_ordered_with<_Tp, _Tp> && 36 requires(__make_const_lvalue_ref<_Tp> __a, __make_const_lvalue_ref<_Tp> __b) { 37 { __a <=> __b } -> __compares_as<_Cat>; 38 }; 39 40 template <class _Tp, class _Up, class _Cat = partial_ordering> 41 concept three_way_comparable_with = 42 three_way_comparable<_Tp, _Cat> && three_way_comparable<_Up, _Cat> && 43 common_reference_with<__make_const_lvalue_ref<_Tp>, __make_const_lvalue_ref<_Up>> && 44 three_way_comparable<common_reference_t<__make_const_lvalue_ref<_Tp>, __make_const_lvalue_ref<_Up>>, _Cat> && 45 __weakly_equality_comparable_with<_Tp, _Up> && __partially_ordered_with<_Tp, _Up> && 46 requires(__make_const_lvalue_ref<_Tp> __t, __make_const_lvalue_ref<_Up> __u) { 47 { __t <=> __u } -> __compares_as<_Cat>; 48 { __u <=> __t } -> __compares_as<_Cat>; 49 }; 50 51 #endif // _LIBCPP_STD_VER >= 20 52 53 _LIBCPP_END_NAMESPACE_STD 54 55 #endif // _LIBCPP___COMPARE_THREE_WAY_COMPARABLE_H 56