xref: /openbsd-src/gnu/llvm/libcxx/include/__compare/three_way_comparable.h (revision 4bdff4bed0e3d54e55670334c7d0077db4170f86)
1*4bdff4beSrobert //===----------------------------------------------------------------------===//
2*4bdff4beSrobert //
3*4bdff4beSrobert // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4*4bdff4beSrobert // See https://llvm.org/LICENSE.txt for license information.
5*4bdff4beSrobert // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6*4bdff4beSrobert //
7*4bdff4beSrobert //===----------------------------------------------------------------------===//
8*4bdff4beSrobert 
9*4bdff4beSrobert #ifndef _LIBCPP___COMPARE_THREE_WAY_COMPARABLE_H
10*4bdff4beSrobert #define _LIBCPP___COMPARE_THREE_WAY_COMPARABLE_H
11*4bdff4beSrobert 
12*4bdff4beSrobert #include <__compare/common_comparison_category.h>
13*4bdff4beSrobert #include <__compare/ordering.h>
14*4bdff4beSrobert #include <__concepts/common_reference_with.h>
15*4bdff4beSrobert #include <__concepts/equality_comparable.h>
16*4bdff4beSrobert #include <__concepts/same_as.h>
17*4bdff4beSrobert #include <__concepts/totally_ordered.h>
18*4bdff4beSrobert #include <__config>
19*4bdff4beSrobert #include <__type_traits/common_reference.h>
20*4bdff4beSrobert #include <__type_traits/make_const_lvalue_ref.h>
21*4bdff4beSrobert 
22*4bdff4beSrobert #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
23*4bdff4beSrobert #  pragma GCC system_header
24*4bdff4beSrobert #endif
25*4bdff4beSrobert 
26*4bdff4beSrobert _LIBCPP_BEGIN_NAMESPACE_STD
27*4bdff4beSrobert 
28*4bdff4beSrobert #if _LIBCPP_STD_VER > 17
29*4bdff4beSrobert 
30*4bdff4beSrobert template<class _Tp, class _Cat>
31*4bdff4beSrobert concept __compares_as =
32*4bdff4beSrobert   same_as<common_comparison_category_t<_Tp, _Cat>, _Cat>;
33*4bdff4beSrobert 
34*4bdff4beSrobert template<class _Tp, class _Cat = partial_ordering>
35*4bdff4beSrobert concept three_way_comparable =
36*4bdff4beSrobert   __weakly_equality_comparable_with<_Tp, _Tp> &&
37*4bdff4beSrobert   __partially_ordered_with<_Tp, _Tp> &&
requires(__make_const_lvalue_ref<_Tp> __a,__make_const_lvalue_ref<_Tp> __b)38*4bdff4beSrobert   requires(__make_const_lvalue_ref<_Tp> __a, __make_const_lvalue_ref<_Tp> __b) {
39*4bdff4beSrobert     { __a <=> __b } -> __compares_as<_Cat>;
40*4bdff4beSrobert   };
41*4bdff4beSrobert 
42*4bdff4beSrobert template<class _Tp, class _Up, class _Cat = partial_ordering>
43*4bdff4beSrobert concept three_way_comparable_with =
44*4bdff4beSrobert   three_way_comparable<_Tp, _Cat> &&
45*4bdff4beSrobert   three_way_comparable<_Up, _Cat> &&
46*4bdff4beSrobert   common_reference_with<__make_const_lvalue_ref<_Tp>, __make_const_lvalue_ref<_Up>> &&
47*4bdff4beSrobert   three_way_comparable<common_reference_t<__make_const_lvalue_ref<_Tp>, __make_const_lvalue_ref<_Up>>, _Cat> &&
48*4bdff4beSrobert   __weakly_equality_comparable_with<_Tp, _Up> &&
49*4bdff4beSrobert   __partially_ordered_with<_Tp, _Up> &&
requires(__make_const_lvalue_ref<_Tp> __t,__make_const_lvalue_ref<_Up> __u)50*4bdff4beSrobert   requires(__make_const_lvalue_ref<_Tp> __t, __make_const_lvalue_ref<_Up> __u) {
51*4bdff4beSrobert     { __t <=> __u } -> __compares_as<_Cat>;
52*4bdff4beSrobert     { __u <=> __t } -> __compares_as<_Cat>;
53*4bdff4beSrobert   };
54*4bdff4beSrobert 
55*4bdff4beSrobert #endif // _LIBCPP_STD_VER > 17
56*4bdff4beSrobert 
57*4bdff4beSrobert _LIBCPP_END_NAMESPACE_STD
58*4bdff4beSrobert 
59*4bdff4beSrobert #endif // _LIBCPP___COMPARE_THREE_WAY_COMPARABLE_H
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