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_PARTIAL_ORDER 10 #define _LIBCPP___COMPARE_PARTIAL_ORDER 11 12 #include <__compare/compare_three_way.h> 13 #include <__compare/ordering.h> 14 #include <__compare/weak_order.h> 15 #include <__config> 16 #include <__type_traits/decay.h> 17 #include <__type_traits/is_same.h> 18 #include <__utility/forward.h> 19 #include <__utility/priority_tag.h> 20 21 #ifndef _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER 22 # pragma GCC system_header 23 #endif 24 25 _LIBCPP_BEGIN_NAMESPACE_STD 26 27 #if _LIBCPP_STD_VER >= 20 28 29 // [cmp.alg] 30 namespace __partial_order { 31 struct __fn { 32 // NOLINTBEGIN(libcpp-robust-against-adl) partial_order should use ADL, but only here 33 template <class _Tp, class _Up> 34 requires is_same_v<decay_t<_Tp>, decay_t<_Up>> 35 _LIBCPP_HIDE_FROM_ABI static constexpr auto __go(_Tp&& __t, _Up&& __u, __priority_tag<2>) noexcept( 36 noexcept(partial_ordering(partial_order(std::forward<_Tp>(__t), std::forward<_Up>(__u))))) 37 -> decltype(partial_ordering(partial_order(std::forward<_Tp>(__t), std::forward<_Up>(__u)))) { 38 return partial_ordering(partial_order(std::forward<_Tp>(__t), std::forward<_Up>(__u))); 39 } 40 // NOLINTEND(libcpp-robust-against-adl) 41 42 template <class _Tp, class _Up> 43 requires is_same_v<decay_t<_Tp>, decay_t<_Up>> 44 _LIBCPP_HIDE_FROM_ABI static constexpr auto __go(_Tp&& __t, _Up&& __u, __priority_tag<1>) noexcept( 45 noexcept(partial_ordering(compare_three_way()(std::forward<_Tp>(__t), std::forward<_Up>(__u))))) 46 -> decltype(partial_ordering(compare_three_way()(std::forward<_Tp>(__t), std::forward<_Up>(__u)))) { 47 return partial_ordering(compare_three_way()(std::forward<_Tp>(__t), std::forward<_Up>(__u))); 48 } 49 50 template <class _Tp, class _Up> 51 requires is_same_v<decay_t<_Tp>, decay_t<_Up>> 52 _LIBCPP_HIDE_FROM_ABI static constexpr auto __go(_Tp&& __t, _Up&& __u, __priority_tag<0>) noexcept( 53 noexcept(partial_ordering(std::weak_order(std::forward<_Tp>(__t), std::forward<_Up>(__u))))) 54 -> decltype(partial_ordering(std::weak_order(std::forward<_Tp>(__t), std::forward<_Up>(__u)))) { 55 return partial_ordering(std::weak_order(std::forward<_Tp>(__t), std::forward<_Up>(__u))); 56 } 57 58 template <class _Tp, class _Up> 59 _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t, _Up&& __u) const 60 noexcept(noexcept(__go(std::forward<_Tp>(__t), std::forward<_Up>(__u), __priority_tag<2>()))) 61 -> decltype(__go(std::forward<_Tp>(__t), std::forward<_Up>(__u), __priority_tag<2>())) { 62 return __go(std::forward<_Tp>(__t), std::forward<_Up>(__u), __priority_tag<2>()); 63 } 64 }; 65 } // namespace __partial_order 66 67 inline namespace __cpo { 68 inline constexpr auto partial_order = __partial_order::__fn{}; 69 } // namespace __cpo 70 71 #endif // _LIBCPP_STD_VER >= 20 72 73 _LIBCPP_END_NAMESPACE_STD 74 75 #endif // _LIBCPP___COMPARE_PARTIAL_ORDER 76