| //===----------------------------------------------------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef _LIBCPP___COMPARE_SYNTH_THREE_WAY_H |
| #define _LIBCPP___COMPARE_SYNTH_THREE_WAY_H |
| |
| #include <__config> |
| #include <__compare/ordering.h> |
| #include <__compare/three_way_comparable.h> |
| #include <__concepts/boolean_testable.h> |
| #include <__utility/declval.h> |
| |
| #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| #pragma GCC system_header |
| #endif |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| #if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS) |
| |
| // [expos.only.func] |
| |
| _LIBCPP_HIDE_FROM_ABI inline constexpr auto __synth_three_way = |
| []<class _Tp, class _Up>(const _Tp& __t, const _Up& __u) |
| requires requires { |
| { __t < __u } -> __boolean_testable; |
| { __u < __t } -> __boolean_testable; |
| } |
| { |
| if constexpr (three_way_comparable_with<_Tp, _Up>) { |
| return __t <=> __u; |
| } else { |
| if (__t < __u) return weak_ordering::less; |
| if (__u < __t) return weak_ordering::greater; |
| return weak_ordering::equivalent; |
| } |
| }; |
| |
| template <class _Tp, class _Up = _Tp> |
| using __synth_three_way_result = decltype(__synth_three_way(declval<_Tp&>(), declval<_Up&>())); |
| |
| #endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS) |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| #endif // _LIBCPP___COMPARE_SYNTH_THREE_WAY_H |