libcxx/include/__algorithm/comp.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___ALGORITHM_COMP_H
  10 #define _LIBCPP___ALGORITHM_COMP_H
  11
  12 #include <__config>
  13 #include <__type_traits/desugars_to.h>
  14 #include <__type_traits/is_integral.h>
  15
  16 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  17 #  pragma GCC system_header
  18 #endif
  19
  20 _LIBCPP_BEGIN_NAMESPACE_STD
  21
  22 struct __equal_to {
  23   template <class _T1, class _T2>
  24   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool operator()(const _T1& __x, const _T2& __y) const {
  25     return __x == __y;
  26   }
  27 };
  28
  29 template <class _Tp, class _Up>
  30 inline const bool __desugars_to_v<__equal_tag, __equal_to, _Tp, _Up> = true;
  31
  32 // The definition is required because __less is part of the ABI, but it's empty
  33 // because all comparisons should be transparent.
  34 template <class _T1 = void, class _T2 = _T1>
  35 struct __less {};
  36
  37 template <>
  38 struct __less<void, void> {
  39   template <class _Tp, class _Up>
  40   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool operator()(const _Tp& __lhs, const _Up& __rhs) const {
  41     return __lhs < __rhs;
  42   }
  43 };
  44
  45 template <class _Tp>
  46 inline const bool __desugars_to_v<__less_tag, __less<>, _Tp, _Tp> = true;
  47
  48 template <class _Tp>
  49 inline const bool __desugars_to_v<__totally_ordered_less_tag, __less<>, _Tp, _Tp> = is_integral<_Tp>::value;
  50
  51 _LIBCPP_END_NAMESPACE_STD
  52
  53 #endif // _LIBCPP___ALGORITHM_COMP_H