libcxx/include/__concepts/totally_ordered.h

   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___CONCEPTS_TOTALLY_ORDERED_H
  10 #define _LIBCPP___CONCEPTS_TOTALLY_ORDERED_H
  11
  12 #include <__concepts/boolean_testable.h>
  13 #include <__concepts/equality_comparable.h>
  14 #include <__config>
  15 #include <type_traits>
  16
  17 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  18 #pragma GCC system_header
  19 #endif
  20
  21 _LIBCPP_BEGIN_NAMESPACE_STD
  22
  23 #if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
  24
  25 // [concept.totallyordered]
  26
  27 template<class _Tp, class _Up>
  28 concept __partially_ordered_with =
  29   requires(__make_const_lvalue_ref<_Tp> __t, __make_const_lvalue_ref<_Up> __u) {
  30     { __t <  __u } -> __boolean_testable;
  31     { __t >  __u } -> __boolean_testable;
  32     { __t <= __u } -> __boolean_testable;
  33     { __t >= __u } -> __boolean_testable;
  34     { __u <  __t } -> __boolean_testable;
  35     { __u >  __t } -> __boolean_testable;
  36     { __u <= __t } -> __boolean_testable;
  37     { __u >= __t } -> __boolean_testable;
  38   };
  39
  40 template<class _Tp>
  41 concept totally_ordered = equality_comparable<_Tp> && __partially_ordered_with<_Tp, _Tp>;
  42
  43 template<class _Tp, class _Up>
  44 concept totally_ordered_with =
  45   totally_ordered<_Tp> && totally_ordered<_Up> &&
  46   equality_comparable_with<_Tp, _Up> &&
  47   totally_ordered<
  48     common_reference_t<
  49       __make_const_lvalue_ref<_Tp>,
  50       __make_const_lvalue_ref<_Up>>> &&
  51   __partially_ordered_with<_Tp, _Up>;
  52
  53 #endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
  54
  55 _LIBCPP_END_NAMESPACE_STD
  56
  57 #endif // _LIBCPP___CONCEPTS_TOTALLY_ORDERED_H