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freebsd
GitHub Repository: freebsd/freebsd-src
 Path: blob/main/contrib/llvm-project/libcxx/include/__compare/three_way_comparable.h
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//===----------------------------------------------------------------------===//

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//

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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

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// See https://llvm.org/LICENSE.txt for license information.

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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

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//

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//===----------------------------------------------------------------------===//

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#ifndef _LIBCPP___COMPARE_THREE_WAY_COMPARABLE_H

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#define _LIBCPP___COMPARE_THREE_WAY_COMPARABLE_H

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#include <__compare/common_comparison_category.h>

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#include <__compare/ordering.h>

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#include <__concepts/common_reference_with.h>

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#include <__concepts/equality_comparable.h>

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#include <__concepts/same_as.h>

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#include <__concepts/totally_ordered.h>

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#include <__config>

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#include <__type_traits/common_reference.h>

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#include <__type_traits/make_const_lvalue_ref.h>

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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)

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#  pragma GCC system_header

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#endif

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_LIBCPP_BEGIN_NAMESPACE_STD

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#if _LIBCPP_STD_VER >= 20

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template <class _Tp, class _Cat>

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concept __compares_as = same_as<common_comparison_category_t<_Tp, _Cat>, _Cat>;

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template <class _Tp, class _Cat = partial_ordering>

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concept three_way_comparable =

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    __weakly_equality_comparable_with<_Tp, _Tp> && __partially_ordered_with<_Tp, _Tp> &&

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    requires(__make_const_lvalue_ref<_Tp> __a, __make_const_lvalue_ref<_Tp> __b) {

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      { __a <=> __b } -> __compares_as<_Cat>;

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    };

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template <class _Tp, class _Up, class _Cat = partial_ordering>

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concept three_way_comparable_with =

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    three_way_comparable<_Tp, _Cat> && three_way_comparable<_Up, _Cat> &&

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    common_reference_with<__make_const_lvalue_ref<_Tp>, __make_const_lvalue_ref<_Up>> &&

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    three_way_comparable<common_reference_t<__make_const_lvalue_ref<_Tp>, __make_const_lvalue_ref<_Up>>, _Cat> &&

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    __weakly_equality_comparable_with<_Tp, _Up> && __partially_ordered_with<_Tp, _Up> &&

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    requires(__make_const_lvalue_ref<_Tp> __t, __make_const_lvalue_ref<_Up> __u) {

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      { __t <=> __u } -> __compares_as<_Cat>;

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      { __u <=> __t } -> __compares_as<_Cat>;

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    };

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#endif // _LIBCPP_STD_VER >= 20

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_LIBCPP_END_NAMESPACE_STD

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#endif // _LIBCPP___COMPARE_THREE_WAY_COMPARABLE_H

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