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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-exception6//7//===----------------------------------------------------------------------===//8 9#ifndef _LIBCPP___COMPARE_WEAK_ORDER10#define _LIBCPP___COMPARE_WEAK_ORDER11 12#include <__compare/compare_three_way.h>13#include <__compare/ordering.h>14#include <__compare/strong_order.h>15#include <__config>16#include <__math/traits.h>17#include <__type_traits/decay.h>18#include <__type_traits/is_floating_point.h>19#include <__type_traits/is_same.h>20#include <__utility/forward.h>21#include <__utility/priority_tag.h>22 23#ifndef _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER24# pragma GCC system_header25#endif26 27_LIBCPP_BEGIN_NAMESPACE_STD28 29#if _LIBCPP_STD_VER >= 2030 31// [cmp.alg]32namespace __weak_order {33void weak_order() = delete;34 35struct __fn {36 // NOLINTBEGIN(libcpp-robust-against-adl) weak_order should use ADL, but only here37 template <class _Tp, class _Up>38 requires is_same_v<decay_t<_Tp>, decay_t<_Up>>39 _LIBCPP_HIDE_FROM_ABI static constexpr auto __go(_Tp&& __t, _Up&& __u, __priority_tag<3>) noexcept(40 noexcept(weak_ordering(weak_order(std::forward<_Tp>(__t), std::forward<_Up>(__u)))))41 -> decltype(weak_ordering(weak_order(std::forward<_Tp>(__t), std::forward<_Up>(__u)))) {42 return weak_ordering(weak_order(std::forward<_Tp>(__t), std::forward<_Up>(__u)));43 }44 // NOLINTEND(libcpp-robust-against-adl)45 46 template <class _Tp, class _Up, class _Dp = decay_t<_Tp>>47 requires is_same_v<_Dp, decay_t<_Up>> && is_floating_point_v<_Dp>48 _LIBCPP_HIDE_FROM_ABI static constexpr weak_ordering __go(_Tp&& __t, _Up&& __u, __priority_tag<2>) noexcept {49 partial_ordering __po = (__t <=> __u);50 if (__po == partial_ordering::less) {51 return weak_ordering::less;52 } else if (__po == partial_ordering::equivalent) {53 return weak_ordering::equivalent;54 } else if (__po == partial_ordering::greater) {55 return weak_ordering::greater;56 } else {57 // Otherwise, at least one of them is a NaN.58 bool __t_is_nan = __math::isnan(__t);59 bool __u_is_nan = __math::isnan(__u);60 bool __t_is_negative = __math::signbit(__t);61 bool __u_is_negative = __math::signbit(__u);62 if (__t_is_nan && __u_is_nan) {63 return (__u_is_negative <=> __t_is_negative);64 } else if (__t_is_nan) {65 return __t_is_negative ? weak_ordering::less : weak_ordering::greater;66 } else {67 return __u_is_negative ? weak_ordering::greater : weak_ordering::less;68 }69 }70 }71 72 template <class _Tp, class _Up>73 requires is_same_v<decay_t<_Tp>, decay_t<_Up>>74 _LIBCPP_HIDE_FROM_ABI static constexpr auto __go(_Tp&& __t, _Up&& __u, __priority_tag<1>) noexcept(75 noexcept(weak_ordering(compare_three_way()(std::forward<_Tp>(__t), std::forward<_Up>(__u)))))76 -> decltype(weak_ordering(compare_three_way()(std::forward<_Tp>(__t), std::forward<_Up>(__u)))) {77 return weak_ordering(compare_three_way()(std::forward<_Tp>(__t), std::forward<_Up>(__u)));78 }79 80 template <class _Tp, class _Up>81 requires is_same_v<decay_t<_Tp>, decay_t<_Up>>82 _LIBCPP_HIDE_FROM_ABI static constexpr auto __go(_Tp&& __t, _Up&& __u, __priority_tag<0>) noexcept(83 noexcept(weak_ordering(std::strong_order(std::forward<_Tp>(__t), std::forward<_Up>(__u)))))84 -> decltype(weak_ordering(std::strong_order(std::forward<_Tp>(__t), std::forward<_Up>(__u)))) {85 return weak_ordering(std::strong_order(std::forward<_Tp>(__t), std::forward<_Up>(__u)));86 }87 88 template <class _Tp, class _Up>89 _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t, _Up&& __u) const90 noexcept(noexcept(__go(std::forward<_Tp>(__t), std::forward<_Up>(__u), __priority_tag<3>())))91 -> decltype(__go(std::forward<_Tp>(__t), std::forward<_Up>(__u), __priority_tag<3>())) {92 return __go(std::forward<_Tp>(__t), std::forward<_Up>(__u), __priority_tag<3>());93 }94};95} // namespace __weak_order96 97inline namespace __cpo {98inline constexpr auto weak_order = __weak_order::__fn{};99} // namespace __cpo100 101#endif // _LIBCPP_STD_VER >= 20102 103_LIBCPP_END_NAMESPACE_STD104 105#endif // _LIBCPP___COMPARE_WEAK_ORDER106