aboutsummaryrefslogtreecommitdiff
path: root/libstdc++-v3/include/bits/range_cmp.h
blob: a77fd5274b9555d28d3af6becc1ff98e4e009588 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
// Concept-constrained comparison implementations -*- C++ -*-

// Copyright (C) 2019 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.

/** @file bits/ranges_function.h
 *  This is an internal header file, included by other library headers.
 *  Do not attempt to use it directly. @headername{functional}
 */

#ifndef _RANGE_CMP_H
#define _RANGE_CMP_H 1

#if __cplusplus > 201703L
# include <bits/move.h>
# include <concepts>

namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION

  struct __is_transparent; // not defined

  // Define std::identity here so that <iterator> and <ranges>
  // don't need to include <bits/stl_function.h> to get it.

  /// [func.identity] The identity function.
  struct identity
  {
    template<typename _Tp>
      constexpr _Tp&&
      operator()(_Tp&& __t) const noexcept
      { return std::forward<_Tp>(__t); }

    using is_transparent = __is_transparent;
  };

namespace ranges
{
  namespace __detail
  {
    // BUILTIN-PTR-CMP(T, ==, U)
    template<typename _Tp, typename _Up>
      concept __eq_builtin_ptr_cmp
	= convertible_to<_Tp, const volatile void*>
	  && convertible_to<_Up, const volatile void*>
	  && (! requires(_Tp&& __t, _Up&& __u)
	      { operator==(std::forward<_Tp>(__t), std::forward<_Up>(__u)); }
	      &&
	      ! requires(_Tp&& __t, _Up&& __u)
	      { std::forward<_Tp>(__t).operator==(std::forward<_Up>(__u)); });

    // BUILTIN-PTR-CMP(T, <, U)
    template<typename _Tp, typename _Up>
      concept __less_builtin_ptr_cmp
	= convertible_to<_Tp, const volatile void*>
	  && convertible_to<_Up, const volatile void*>
	  && (! requires(_Tp&& __t, _Up&& __u)
	      { operator<(std::forward<_Tp>(__t), std::forward<_Up>(__u)); }
	      && ! requires(_Tp&& __t, _Up&& __u)
	      { std::forward<_Tp>(__t).operator<(std::forward<_Up>(__u)); });
  } // namespace __detail

  // [range.cmp] Concept-constrained comparisons

  /// ranges::equal_to function object type.
  struct equal_to
  {
    template<typename _Tp, typename _Up>
      requires equality_comparable_with<_Tp, _Up>
	|| __detail::__eq_builtin_ptr_cmp<_Tp, _Up>
      constexpr bool
      operator()(_Tp&& __t, _Up&& __u) const
      noexcept(noexcept(std::declval<_Tp>() == std::declval<_Up>()))
      { return std::forward<_Tp>(__t) == std::forward<_Up>(__u); }

    using is_transparent = __is_transparent;
  };

  /// ranges::not_equal_to function object type.
  struct not_equal_to
  {
    template<typename _Tp, typename _Up>
      requires equality_comparable_with<_Tp, _Up>
	|| __detail::__eq_builtin_ptr_cmp<_Tp, _Up>
      constexpr bool
      operator()(_Tp&& __t, _Up&& __u) const
      noexcept(noexcept(std::declval<_Up>() == std::declval<_Tp>()))
      { return !equal_to{}(std::forward<_Tp>(__t), std::forward<_Up>(__u)); }

    using is_transparent = __is_transparent;
  };

  /// ranges::less function object type.
  struct less
  {
    template<typename _Tp, typename _Up>
      requires totally_ordered_with<_Tp, _Up>
	|| __detail::__less_builtin_ptr_cmp<_Tp, _Up>
      constexpr bool
      operator()(_Tp&& __t, _Up&& __u) const
      noexcept(noexcept(std::declval<_Tp>() < std::declval<_Up>()))
      {
	if constexpr (__detail::__less_builtin_ptr_cmp<_Tp, _Up>)
	  {
#ifdef __cpp_lib_is_constant_evaluated
	    if (std::is_constant_evaluated())
	      return __t < __u;
#endif
	    auto __x = reinterpret_cast<__UINTPTR_TYPE__>(
	      static_cast<const volatile void*>(std::forward<_Tp>(__t)));
	    auto __y = reinterpret_cast<__UINTPTR_TYPE__>(
	      static_cast<const volatile void*>(std::forward<_Up>(__u)));
	    return __x < __y;
	  }
	else
	  return std::forward<_Tp>(__t) < std::forward<_Up>(__u);
      }

    using is_transparent = __is_transparent;
  };

  /// ranges::greater function object type.
  struct greater
  {
    template<typename _Tp, typename _Up>
      requires totally_ordered_with<_Tp, _Up>
	|| __detail::__less_builtin_ptr_cmp<_Up, _Tp>
      constexpr bool
      operator()(_Tp&& __t, _Up&& __u) const
      noexcept(noexcept(std::declval<_Up>() < std::declval<_Tp>()))
      { return less{}(std::forward<_Up>(__u), std::forward<_Tp>(__t)); }

    using is_transparent = __is_transparent;
  };

  /// ranges::greater_equal function object type.
  struct greater_equal
  {
    template<typename _Tp, typename _Up>
      requires totally_ordered_with<_Tp, _Up>
	|| __detail::__less_builtin_ptr_cmp<_Tp, _Up>
      constexpr bool
      operator()(_Tp&& __t, _Up&& __u) const
      noexcept(noexcept(std::declval<_Tp>() < std::declval<_Up>()))
      { return !less{}(std::forward<_Tp>(__t), std::forward<_Up>(__u)); }

    using is_transparent = __is_transparent;
  };

  /// ranges::less_equal function object type.
  struct less_equal
  {
    template<typename _Tp, typename _Up>
      requires totally_ordered_with<_Tp, _Up>
	|| __detail::__less_builtin_ptr_cmp<_Up, _Tp>
      constexpr bool
      operator()(_Tp&& __t, _Up&& __u) const
      noexcept(noexcept(std::declval<_Up>() < std::declval<_Tp>()))
      { return !less{}(std::forward<_Up>(__u), std::forward<_Tp>(__t)); }

    using is_transparent = __is_transparent;
  };

} // namespace ranges
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
#endif // C++20
#endif // _RANGE_CMP_H