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//===----------------------------------------------------------------------===//
//
// 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_WEAK_ORDER
#define _LIBCPP___COMPARE_WEAK_ORDER
#include <__compare/compare_three_way.h>
#include <__compare/ordering.h>
#include <__compare/strong_order.h>
#include <__config>
#include <__utility/forward.h>
#include <__utility/priority_tag.h>
#include <cmath>
#include <type_traits>
#ifndef _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER
# pragma GCC system_header
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
#if _LIBCPP_STD_VER > 17
// [cmp.alg]
namespace __weak_order {
struct __fn {
template<class _Tp, class _Up>
requires is_same_v<decay_t<_Tp>, decay_t<_Up>>
_LIBCPP_HIDE_FROM_ABI static constexpr auto
__go(_Tp&& __t, _Up&& __u, __priority_tag<3>)
noexcept(noexcept(weak_ordering(weak_order(_VSTD::forward<_Tp>(__t), _VSTD::forward<_Up>(__u)))))
-> decltype( weak_ordering(weak_order(_VSTD::forward<_Tp>(__t), _VSTD::forward<_Up>(__u))))
{ return weak_ordering(weak_order(_VSTD::forward<_Tp>(__t), _VSTD::forward<_Up>(__u))); }
template<class _Tp, class _Up, class _Dp = decay_t<_Tp>>
requires is_same_v<_Dp, decay_t<_Up>> && is_floating_point_v<_Dp>
_LIBCPP_HIDE_FROM_ABI static constexpr weak_ordering
__go(_Tp&& __t, _Up&& __u, __priority_tag<2>) noexcept
{
partial_ordering __po = (__t <=> __u);
if (__po == partial_ordering::less) {
return weak_ordering::less;
} else if (__po == partial_ordering::equivalent) {
return weak_ordering::equivalent;
} else if (__po == partial_ordering::greater) {
return weak_ordering::greater;
} else {
// Otherwise, at least one of them is a NaN.
bool __t_is_nan = _VSTD::isnan(__t);
bool __u_is_nan = _VSTD::isnan(__u);
bool __t_is_negative = _VSTD::signbit(__t);
bool __u_is_negative = _VSTD::signbit(__u);
if (__t_is_nan && __u_is_nan) {
return (__u_is_negative <=> __t_is_negative);
} else if (__t_is_nan) {
return __t_is_negative ? weak_ordering::less : weak_ordering::greater;
} else {
return __u_is_negative ? weak_ordering::greater : weak_ordering::less;
}
}
}
template<class _Tp, class _Up>
requires is_same_v<decay_t<_Tp>, decay_t<_Up>>
_LIBCPP_HIDE_FROM_ABI static constexpr auto
__go(_Tp&& __t, _Up&& __u, __priority_tag<1>)
noexcept(noexcept(weak_ordering(compare_three_way()(_VSTD::forward<_Tp>(__t), _VSTD::forward<_Up>(__u)))))
-> decltype( weak_ordering(compare_three_way()(_VSTD::forward<_Tp>(__t), _VSTD::forward<_Up>(__u))))
{ return weak_ordering(compare_three_way()(_VSTD::forward<_Tp>(__t), _VSTD::forward<_Up>(__u))); }
template<class _Tp, class _Up>
requires is_same_v<decay_t<_Tp>, decay_t<_Up>>
_LIBCPP_HIDE_FROM_ABI static constexpr auto
__go(_Tp&& __t, _Up&& __u, __priority_tag<0>)
noexcept(noexcept(weak_ordering(_VSTD::strong_order(_VSTD::forward<_Tp>(__t), _VSTD::forward<_Up>(__u)))))
-> decltype( weak_ordering(_VSTD::strong_order(_VSTD::forward<_Tp>(__t), _VSTD::forward<_Up>(__u))))
{ return weak_ordering(_VSTD::strong_order(_VSTD::forward<_Tp>(__t), _VSTD::forward<_Up>(__u))); }
template<class _Tp, class _Up>
_LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t, _Up&& __u) const
noexcept(noexcept(__go(_VSTD::forward<_Tp>(__t), _VSTD::forward<_Up>(__u), __priority_tag<3>())))
-> decltype( __go(_VSTD::forward<_Tp>(__t), _VSTD::forward<_Up>(__u), __priority_tag<3>()))
{ return __go(_VSTD::forward<_Tp>(__t), _VSTD::forward<_Up>(__u), __priority_tag<3>()); }
};
} // namespace __weak_order
inline namespace __cpo {
inline constexpr auto weak_order = __weak_order::__fn{};
} // namespace __cpo
#endif // _LIBCPP_STD_VER > 17
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___COMPARE_WEAK_ORDER
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