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145
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1 // -*- C++ -*- operator<=> three-way comparison support.
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2
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3 // Copyright (C) 2019-2020 Free Software Foundation, Inc.
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4 //
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5 // This file is part of GCC.
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6 //
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7 // GCC is free software; you can redistribute it and/or modify
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8 // it under the terms of the GNU General Public License as published by
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9 // the Free Software Foundation; either version 3, or (at your option)
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10 // any later version.
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11 //
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12 // GCC is distributed in the hope that it will be useful,
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13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
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14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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15 // GNU General Public License for more details.
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16 //
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17 // Under Section 7 of GPL version 3, you are granted additional
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18 // permissions described in the GCC Runtime Library Exception, version
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19 // 3.1, as published by the Free Software Foundation.
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20
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21 // You should have received a copy of the GNU General Public License and
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22 // a copy of the GCC Runtime Library Exception along with this program;
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23 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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24 // <http://www.gnu.org/licenses/>.
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25
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26 /** @file compare
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27 * This is a Standard C++ Library header.
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28 */
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29
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30 #ifndef _COMPARE
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31 #define _COMPARE
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32
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33 #pragma GCC system_header
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34
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35 #if __cplusplus > 201703L && __cpp_impl_three_way_comparison >= 201907L
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36
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37 #pragma GCC visibility push(default)
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38
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39 #include <concepts>
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40
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41 #if __cpp_lib_concepts
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42 # define __cpp_lib_three_way_comparison 201711L
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43 #endif
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44
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45 namespace std
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46 {
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47 // [cmp.categories], comparison category types
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48
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49 namespace __cmp_cat
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50 {
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51 using type = signed char;
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52
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53 enum class _Ord : type { equivalent = 0, less = -1, greater = 1 };
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54
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55 enum class _Ncmp : type { _Unordered = 2 };
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56
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57 struct __unspec
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58 {
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59 constexpr __unspec(__unspec*) { }
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60 };
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61 }
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62
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63 class partial_ordering
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64 {
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65 // less=0xff, equiv=0x00, greater=0x01, unordered=0x02
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66 __cmp_cat::type _M_value;
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67
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68 constexpr explicit
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69 partial_ordering(__cmp_cat::_Ord __v) noexcept
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70 : _M_value(__cmp_cat::type(__v))
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71 { }
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72
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73 constexpr explicit
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74 partial_ordering(__cmp_cat::_Ncmp __v) noexcept
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75 : _M_value(__cmp_cat::type(__v))
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76 { }
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77
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78 friend class weak_ordering;
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79 friend class strong_ordering;
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80
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81 public:
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82 // valid values
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83 static const partial_ordering less;
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84 static const partial_ordering equivalent;
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85 static const partial_ordering greater;
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86 static const partial_ordering unordered;
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87
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88 // comparisons
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89 friend constexpr bool
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90 operator==(partial_ordering __v, __cmp_cat::__unspec) noexcept
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91 { return __v._M_value == 0; }
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92
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93 friend constexpr bool
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94 operator==(partial_ordering, partial_ordering) noexcept = default;
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95
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96 friend constexpr bool
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97 operator< (partial_ordering __v, __cmp_cat::__unspec) noexcept
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98 { return __v._M_value == -1; }
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99
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100 friend constexpr bool
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101 operator> (partial_ordering __v, __cmp_cat::__unspec) noexcept
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102 { return __v._M_value == 1; }
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103
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104 friend constexpr bool
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105 operator<=(partial_ordering __v, __cmp_cat::__unspec) noexcept
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106 { return __v._M_value <= 0; }
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107
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108 friend constexpr bool
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109 operator>=(partial_ordering __v, __cmp_cat::__unspec) noexcept
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110 { return __cmp_cat::type(__v._M_value & 1) == __v._M_value; }
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111
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112 friend constexpr bool
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113 operator< (__cmp_cat::__unspec, partial_ordering __v) noexcept
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114 { return __v._M_value == 1; }
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115
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116 friend constexpr bool
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117 operator> (__cmp_cat::__unspec, partial_ordering __v) noexcept
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118 { return __v._M_value == -1; }
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119
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120 friend constexpr bool
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121 operator<=(__cmp_cat::__unspec, partial_ordering __v) noexcept
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122 { return __cmp_cat::type(__v._M_value & 1) == __v._M_value; }
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123
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124 friend constexpr bool
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125 operator>=(__cmp_cat::__unspec, partial_ordering __v) noexcept
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126 { return 0 >= __v._M_value; }
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127
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128 friend constexpr partial_ordering
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129 operator<=>(partial_ordering __v, __cmp_cat::__unspec) noexcept
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130 { return __v; }
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131
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132 friend constexpr partial_ordering
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133 operator<=>(__cmp_cat::__unspec, partial_ordering __v) noexcept
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134 {
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135 if (__v._M_value & 1)
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136 return partial_ordering(__cmp_cat::_Ord(-__v._M_value));
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137 else
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138 return __v;
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139 }
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140 };
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141
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142 // valid values' definitions
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143 inline constexpr partial_ordering
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144 partial_ordering::less(__cmp_cat::_Ord::less);
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145
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146 inline constexpr partial_ordering
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147 partial_ordering::equivalent(__cmp_cat::_Ord::equivalent);
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148
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149 inline constexpr partial_ordering
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150 partial_ordering::greater(__cmp_cat::_Ord::greater);
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151
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152 inline constexpr partial_ordering
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153 partial_ordering::unordered(__cmp_cat::_Ncmp::_Unordered);
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154
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155 class weak_ordering
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156 {
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157 __cmp_cat::type _M_value;
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158
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159 constexpr explicit
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160 weak_ordering(__cmp_cat::_Ord __v) noexcept : _M_value(__cmp_cat::type(__v))
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161 { }
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162
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163 friend class strong_ordering;
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164
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165 public:
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166 // valid values
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167 static const weak_ordering less;
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168 static const weak_ordering equivalent;
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169 static const weak_ordering greater;
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170
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171 constexpr operator partial_ordering() const noexcept
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172 { return partial_ordering(__cmp_cat::_Ord(_M_value)); }
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173
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174 // comparisons
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175 friend constexpr bool
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176 operator==(weak_ordering __v, __cmp_cat::__unspec) noexcept
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177 { return __v._M_value == 0; }
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178
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179 friend constexpr bool
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180 operator==(weak_ordering, weak_ordering) noexcept = default;
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181
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182 friend constexpr bool
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183 operator< (weak_ordering __v, __cmp_cat::__unspec) noexcept
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184 { return __v._M_value < 0; }
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185
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186 friend constexpr bool
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187 operator> (weak_ordering __v, __cmp_cat::__unspec) noexcept
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188 { return __v._M_value > 0; }
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189
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190 friend constexpr bool
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191 operator<=(weak_ordering __v, __cmp_cat::__unspec) noexcept
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192 { return __v._M_value <= 0; }
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193
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194 friend constexpr bool
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195 operator>=(weak_ordering __v, __cmp_cat::__unspec) noexcept
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196 { return __v._M_value >= 0; }
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197
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198 friend constexpr bool
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199 operator< (__cmp_cat::__unspec, weak_ordering __v) noexcept
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200 { return 0 < __v._M_value; }
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201
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202 friend constexpr bool
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203 operator> (__cmp_cat::__unspec, weak_ordering __v) noexcept
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204 { return 0 > __v._M_value; }
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205
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206 friend constexpr bool
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207 operator<=(__cmp_cat::__unspec, weak_ordering __v) noexcept
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208 { return 0 <= __v._M_value; }
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209
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210 friend constexpr bool
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211 operator>=(__cmp_cat::__unspec, weak_ordering __v) noexcept
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212 { return 0 >= __v._M_value; }
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213
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214 friend constexpr weak_ordering
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215 operator<=>(weak_ordering __v, __cmp_cat::__unspec) noexcept
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216 { return __v; }
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217
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218 friend constexpr weak_ordering
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219 operator<=>(__cmp_cat::__unspec, weak_ordering __v) noexcept
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220 { return weak_ordering(__cmp_cat::_Ord(-__v._M_value)); }
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221 };
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222
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223 // valid values' definitions
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224 inline constexpr weak_ordering
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225 weak_ordering::less(__cmp_cat::_Ord::less);
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226
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227 inline constexpr weak_ordering
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228 weak_ordering::equivalent(__cmp_cat::_Ord::equivalent);
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229
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230 inline constexpr weak_ordering
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231 weak_ordering::greater(__cmp_cat::_Ord::greater);
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232
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233 class strong_ordering
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234 {
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235 __cmp_cat::type _M_value;
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236
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237 constexpr explicit
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238 strong_ordering(__cmp_cat::_Ord __v) noexcept
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239 : _M_value(__cmp_cat::type(__v))
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240 { }
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241
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242 public:
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243 // valid values
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244 static const strong_ordering less;
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245 static const strong_ordering equal;
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246 static const strong_ordering equivalent;
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247 static const strong_ordering greater;
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248
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249 constexpr operator partial_ordering() const noexcept
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250 { return partial_ordering(__cmp_cat::_Ord(_M_value)); }
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251
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252 constexpr operator weak_ordering() const noexcept
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253 { return weak_ordering(__cmp_cat::_Ord(_M_value)); }
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254
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255 // comparisons
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256 friend constexpr bool
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257 operator==(strong_ordering __v, __cmp_cat::__unspec) noexcept
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258 { return __v._M_value == 0; }
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259
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260 friend constexpr bool
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261 operator==(strong_ordering, strong_ordering) noexcept = default;
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262
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263 friend constexpr bool
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264 operator< (strong_ordering __v, __cmp_cat::__unspec) noexcept
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265 { return __v._M_value < 0; }
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266
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267 friend constexpr bool
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268 operator> (strong_ordering __v, __cmp_cat::__unspec) noexcept
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269 { return __v._M_value > 0; }
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270
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271 friend constexpr bool
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272 operator<=(strong_ordering __v, __cmp_cat::__unspec) noexcept
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273 { return __v._M_value <= 0; }
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274
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275 friend constexpr bool
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276 operator>=(strong_ordering __v, __cmp_cat::__unspec) noexcept
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277 { return __v._M_value >= 0; }
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278
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279 friend constexpr bool
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280 operator< (__cmp_cat::__unspec, strong_ordering __v) noexcept
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281 { return 0 < __v._M_value; }
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282
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283 friend constexpr bool
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284 operator> (__cmp_cat::__unspec, strong_ordering __v) noexcept
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285 { return 0 > __v._M_value; }
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286
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287 friend constexpr bool
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288 operator<=(__cmp_cat::__unspec, strong_ordering __v) noexcept
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289 { return 0 <= __v._M_value; }
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290
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291 friend constexpr bool
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292 operator>=(__cmp_cat::__unspec, strong_ordering __v) noexcept
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293 { return 0 >= __v._M_value; }
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294
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295 friend constexpr strong_ordering
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296 operator<=>(strong_ordering __v, __cmp_cat::__unspec) noexcept
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297 { return __v; }
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298
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299 friend constexpr strong_ordering
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300 operator<=>(__cmp_cat::__unspec, strong_ordering __v) noexcept
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301 { return strong_ordering(__cmp_cat::_Ord(-__v._M_value)); }
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302 };
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303
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304 // valid values' definitions
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305 inline constexpr strong_ordering
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306 strong_ordering::less(__cmp_cat::_Ord::less);
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307
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308 inline constexpr strong_ordering
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309 strong_ordering::equal(__cmp_cat::_Ord::equivalent);
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310
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311 inline constexpr strong_ordering
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312 strong_ordering::equivalent(__cmp_cat::_Ord::equivalent);
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313
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314 inline constexpr strong_ordering
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315 strong_ordering::greater(__cmp_cat::_Ord::greater);
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316
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317
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318 // named comparison functions
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319 constexpr bool
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320 is_eq(partial_ordering __cmp) noexcept
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321 { return __cmp == 0; }
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322
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323 constexpr bool
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324 is_neq(partial_ordering __cmp) noexcept
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325 { return __cmp != 0; }
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326
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327 constexpr bool
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328 is_lt (partial_ordering __cmp) noexcept
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329 { return __cmp < 0; }
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330
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331 constexpr bool
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332 is_lteq(partial_ordering __cmp) noexcept
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333 { return __cmp <= 0; }
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334
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335 constexpr bool
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336 is_gt (partial_ordering __cmp) noexcept
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337 { return __cmp > 0; }
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338
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339 constexpr bool
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340 is_gteq(partial_ordering __cmp) noexcept
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341 { return __cmp >= 0; }
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342
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343 namespace __detail
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344 {
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345 template<typename _Tp>
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346 inline constexpr unsigned __cmp_cat_id = 1;
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347 template<>
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348 inline constexpr unsigned __cmp_cat_id<partial_ordering> = 2;
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349 template<>
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350 inline constexpr unsigned __cmp_cat_id<weak_ordering> = 4;
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351 template<>
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352 inline constexpr unsigned __cmp_cat_id<strong_ordering> = 8;
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353
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354 template<typename... _Ts>
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355 constexpr auto __common_cmp_cat()
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356 {
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357 constexpr unsigned __cats = (__cmp_cat_id<_Ts> | ...);
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358 // If any Ti is not a comparison category type, U is void.
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359 if constexpr (__cats & 1)
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360 return;
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361 // Otherwise, if at least one Ti is std::partial_ordering,
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362 // U is std::partial_ordering.
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363 else if constexpr (bool(__cats & __cmp_cat_id<partial_ordering>))
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364 return partial_ordering::equivalent;
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365 // Otherwise, if at least one Ti is std::weak_ordering,
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366 // U is std::weak_ordering.
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367 else if constexpr (bool(__cats & __cmp_cat_id<weak_ordering>))
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368 return weak_ordering::equivalent;
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369 // Otherwise, U is std::strong_ordering.
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370 else
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371 return strong_ordering::equivalent;
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372 }
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373 } // namespace __detail
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374
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375 // [cmp.common], common comparison category type
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376 template<typename... _Ts>
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377 struct common_comparison_category
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378 {
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379 using type = decltype(__detail::__common_cmp_cat<_Ts...>());
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380 };
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381
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382 // Partial specializations for one and zero argument cases.
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383
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384 template<typename _Tp>
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385 struct common_comparison_category<_Tp>
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386 { using type = void; };
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387
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388 template<>
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389 struct common_comparison_category<partial_ordering>
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390 { using type = partial_ordering; };
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391
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392 template<>
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393 struct common_comparison_category<weak_ordering>
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394 { using type = weak_ordering; };
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395
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396 template<>
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397 struct common_comparison_category<strong_ordering>
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398 { using type = strong_ordering; };
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399
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400 template<>
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401 struct common_comparison_category<>
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402 { using type = strong_ordering; };
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403
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404 template<typename... _Ts>
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405 using common_comparison_category_t
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406 = typename common_comparison_category<_Ts...>::type;
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407
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408 #if __cpp_lib_concepts
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409 namespace __detail
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410 {
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411 template<typename _Tp, typename _Cat>
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412 concept __compares_as
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413 = same_as<common_comparison_category_t<_Tp, _Cat>, _Cat>;
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414
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415 template<typename _Tp, typename _Up>
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416 concept __partially_ordered_with
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417 = requires(const remove_reference_t<_Tp>& __t,
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418 const remove_reference_t<_Up>& __u) {
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419 { __t < __u } -> boolean;
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420 { __t > __u } -> boolean;
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421 { __t <= __u } -> boolean;
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422 { __t >= __u } -> boolean;
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423 { __u < __t } -> boolean;
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424 { __u > __t } -> boolean;
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425 { __u <= __t } -> boolean;
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426 { __u >= __t } -> boolean;
|
|
|
427 };
|
|
|
428 } // namespace __detail
|
|
|
429
|
|
|
430 // [cmp.concept], concept three_way_comparable
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|
|
431 template<typename _Tp, typename _Cat = partial_ordering>
|
|
|
432 concept three_way_comparable
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|
|
433 = __detail::__weakly_eq_cmp_with<_Tp, _Tp>
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|
|
434 && (!convertible_to<_Cat, partial_ordering>
|
|
|
435 || __detail::__partially_ordered_with<_Tp, _Tp>)
|
|
|
436 && requires(const remove_reference_t<_Tp>& __a,
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|
|
437 const remove_reference_t<_Tp>& __b) {
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|
|
438 { __a <=> __b } -> __detail::__compares_as<_Cat>;
|
|
|
439 };
|
|
|
440
|
|
|
441 template<typename _Tp, typename _Up, typename _Cat = partial_ordering>
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|
|
442 concept three_way_comparable_with
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|
|
443 = __detail::__weakly_eq_cmp_with<_Tp, _Up>
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|
444 && (!convertible_to<_Cat, partial_ordering>
|
|
|
445 || __detail::__partially_ordered_with<_Tp, _Up>)
|
|
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446 && three_way_comparable<_Tp, _Cat>
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|
|
447 && three_way_comparable<_Up, _Cat>
|
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|
448 && common_reference_with<const remove_reference_t<_Tp>&,
|
|
|
449 const remove_reference_t<_Up>&>
|
|
|
450 && three_way_comparable<
|
|
|
451 common_reference_t<const remove_reference_t<_Tp>&,
|
|
|
452 const remove_reference_t<_Up>&>, _Cat>
|
|
|
453 && requires(const remove_reference_t<_Tp>& __t,
|
|
|
454 const remove_reference_t<_Up>& __u) {
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|
455 { __t <=> __u } -> __detail::__compares_as<_Cat>;
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|
456 { __u <=> __t } -> __detail::__compares_as<_Cat>;
|
|
|
457 };
|
|
|
458
|
|
|
459 namespace __detail
|
|
|
460 {
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|
|
461 template<typename _Tp, typename _Up>
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|
462 using __cmp3way_res_t
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|
|
463 = decltype(std::declval<_Tp>() <=> std::declval<_Up>());
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464
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|
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465 // Implementation of std::compare_three_way_result.
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|
|
466 // It is undefined for a program to add specializations of
|
|
|
467 // std::compare_three_way_result, so the std::compare_three_way_result_t
|
|
|
468 // alias ignores std::compare_three_way_result and uses
|
|
|
469 // __detail::__cmp3way_res_impl directly instead.
|
|
|
470 template<typename _Tp, typename _Up>
|
|
|
471 struct __cmp3way_res_impl
|
|
|
472 { };
|
|
|
473
|
|
|
474 template<typename _Tp, typename _Up>
|
|
|
475 requires requires { typename __cmp3way_res_t<__cref<_Tp>, __cref<_Up>>; }
|
|
|
476 struct __cmp3way_res_impl<_Tp, _Up>
|
|
|
477 {
|
|
|
478 using type = __cmp3way_res_t<__cref<_Tp>, __cref<_Up>>;
|
|
|
479 };
|
|
|
480 } // namespace __detail
|
|
|
481
|
|
|
482 /// [cmp.result], result of three-way comparison
|
|
|
483 template<typename _Tp, typename _Up = _Tp>
|
|
|
484 struct compare_three_way_result
|
|
|
485 : __detail::__cmp3way_res_impl<_Tp, _Up>
|
|
|
486 { };
|
|
|
487
|
|
|
488 /// [cmp.result], result of three-way comparison
|
|
|
489 template<typename _Tp, typename _Up = _Tp>
|
|
|
490 using compare_three_way_result_t
|
|
|
491 = typename __detail::__cmp3way_res_impl<_Tp, _Up>::type;
|
|
|
492
|
|
|
493 namespace __detail
|
|
|
494 {
|
|
|
495 // BUILTIN-PTR-THREE-WAY(T, U)
|
|
|
496 template<typename _Tp, typename _Up>
|
|
|
497 concept __3way_builtin_ptr_cmp
|
|
|
498 = three_way_comparable_with<_Tp, _Up>
|
|
|
499 && convertible_to<_Tp, const volatile void*>
|
|
|
500 && convertible_to<_Up, const volatile void*>
|
|
|
501 && ! requires(_Tp&& __t, _Up&& __u)
|
|
|
502 { operator<=>(static_cast<_Tp&&>(__t), static_cast<_Up&&>(__u)); }
|
|
|
503 && ! requires(_Tp&& __t, _Up&& __u)
|
|
|
504 { static_cast<_Tp&&>(__t).operator<=>(static_cast<_Up&&>(__u)); };
|
|
|
505 } // namespace __detail
|
|
|
506
|
|
|
507 // [cmp.object], typename compare_three_way
|
|
|
508 struct compare_three_way
|
|
|
509 {
|
|
|
510 template<typename _Tp, typename _Up>
|
|
|
511 requires three_way_comparable_with<_Tp, _Up>
|
|
|
512 constexpr auto
|
|
|
513 operator()(_Tp&& __t, _Up&& __u) const noexcept
|
|
|
514 {
|
|
|
515 if constexpr (__detail::__3way_builtin_ptr_cmp<_Tp, _Up>)
|
|
|
516 {
|
|
|
517 auto __pt = static_cast<const volatile void*>(__t);
|
|
|
518 auto __pu = static_cast<const volatile void*>(__u);
|
|
|
519 if (__builtin_is_constant_evaluated())
|
|
|
520 return __pt <=> __pu;
|
|
|
521 auto __it = reinterpret_cast<__UINTPTR_TYPE__>(__pt);
|
|
|
522 auto __iu = reinterpret_cast<__UINTPTR_TYPE__>(__pu);
|
|
|
523 return __it <=> __iu;
|
|
|
524 }
|
|
|
525 else
|
|
|
526 return static_cast<_Tp&&>(__t) <=> static_cast<_Up&&>(__u);
|
|
|
527 }
|
|
|
528
|
|
|
529 using is_transparent = void;
|
|
|
530 };
|
|
|
531
|
|
|
532 namespace __cmp_cust
|
|
|
533 {
|
|
|
534 template<floating_point _Tp>
|
|
|
535 constexpr weak_ordering
|
|
|
536 __fp_weak_ordering(_Tp __e, _Tp __f)
|
|
|
537 {
|
|
|
538 // Returns an integer with the same sign as the argument, and magnitude
|
|
|
539 // indicating the classification: zero=1 subnorm=2 norm=3 inf=4 nan=5
|
|
|
540 auto __cat = [](_Tp __fp) -> int {
|
|
|
541 const int __sign = __builtin_signbit(__fp) ? -1 : 1;
|
|
|
542 if (__builtin_isnormal(__fp))
|
|
|
543 return (__fp == 0 ? 1 : 3) * __sign;
|
|
|
544 if (__builtin_isnan(__fp))
|
|
|
545 return 5 * __sign;
|
|
|
546 if (int __inf = __builtin_isinf_sign(__fp))
|
|
|
547 return 4 * __inf;
|
|
|
548 return 2 * __sign;
|
|
|
549 };
|
|
|
550
|
|
|
551 auto __po = __e <=> __f;
|
|
|
552 if (is_lt(__po))
|
|
|
553 return weak_ordering::less;
|
|
|
554 else if (is_gt(__po))
|
|
|
555 return weak_ordering::greater;
|
|
|
556 else if (__po == partial_ordering::equivalent)
|
|
|
557 return weak_ordering::equivalent;
|
|
|
558 else // unordered, at least one argument is NaN
|
|
|
559 {
|
|
|
560 // return -1 for negative nan, +1 for positive nan, 0 otherwise.
|
|
|
561 auto __isnan_sign = [](_Tp __fp) -> int {
|
|
|
562 return __builtin_isnan(__fp)
|
|
|
563 ? __builtin_signbit(__fp) ? -1 : 1
|
|
|
564 : 0;
|
|
|
565 };
|
|
|
566 auto __ord = __isnan_sign(__e) <=> __isnan_sign(__f);
|
|
|
567 if (is_eq(__ord))
|
|
|
568 return weak_ordering::equivalent;
|
|
|
569 else if (is_lt(__ord))
|
|
|
570 return weak_ordering::less;
|
|
|
571 else
|
|
|
572 return weak_ordering::greater;
|
|
|
573 }
|
|
|
574 }
|
|
|
575
|
|
|
576 template<typename _Tp, typename _Up>
|
|
|
577 concept __adl_strong = requires(_Tp&& __t, _Up&& __u)
|
|
|
578 {
|
|
|
579 strong_ordering(strong_order(static_cast<_Tp&&>(__t),
|
|
|
580 static_cast<_Up&&>(__u)));
|
|
|
581 };
|
|
|
582
|
|
|
583 template<typename _Tp, typename _Up>
|
|
|
584 concept __adl_weak = requires(_Tp&& __t, _Up&& __u)
|
|
|
585 {
|
|
|
586 weak_ordering(weak_order(static_cast<_Tp&&>(__t),
|
|
|
587 static_cast<_Up&&>(__u)));
|
|
|
588 };
|
|
|
589
|
|
|
590 template<typename _Tp, typename _Up>
|
|
|
591 concept __adl_partial = requires(_Tp&& __t, _Up&& __u)
|
|
|
592 {
|
|
|
593 partial_ordering(partial_order(static_cast<_Tp&&>(__t),
|
|
|
594 static_cast<_Up&&>(__u)));
|
|
|
595 };
|
|
|
596
|
|
|
597 template<typename _Ord, typename _Tp, typename _Up>
|
|
|
598 concept __op_cmp = requires(_Tp&& __t, _Up&& __u)
|
|
|
599 {
|
|
|
600 _Ord(static_cast<_Tp&&>(__t) <=> static_cast<_Up&&>(__u));
|
|
|
601 };
|
|
|
602
|
|
|
603 template<typename _Tp, typename _Up>
|
|
|
604 concept __strongly_ordered
|
|
|
605 = __adl_strong<_Tp, _Up>
|
|
|
606 // FIXME: || floating_point<remove_reference_t<_Tp>>
|
|
|
607 || __op_cmp<strong_ordering, _Tp, _Up>;
|
|
|
608
|
|
|
609 class _Strong_order
|
|
|
610 {
|
|
|
611 template<typename _Tp, typename _Up>
|
|
|
612 static constexpr bool
|
|
|
613 _S_noexcept()
|
|
|
614 {
|
|
|
615 if constexpr (floating_point<decay_t<_Tp>>)
|
|
|
616 return true;
|
|
|
617 else if constexpr (__adl_strong<_Tp, _Up>)
|
|
|
618 return noexcept(strong_ordering(strong_order(std::declval<_Tp>(),
|
|
|
619 std::declval<_Up>())));
|
|
|
620 else if constexpr (__op_cmp<strong_ordering, _Tp, _Up>)
|
|
|
621 return noexcept(std::declval<_Tp>() <=> std::declval<_Up>());
|
|
|
622 }
|
|
|
623
|
|
|
624 friend class _Weak_order;
|
|
|
625 friend class _Strong_fallback;
|
|
|
626
|
|
|
627 public:
|
|
|
628 template<typename _Tp, typename _Up>
|
|
|
629 requires __strongly_ordered<_Tp, _Up>
|
|
|
630 constexpr strong_ordering
|
|
|
631 operator()(_Tp&& __e, _Up&& __f) const
|
|
|
632 noexcept(_S_noexcept<_Tp, _Up>())
|
|
|
633 {
|
|
|
634 static_assert(same_as<decay_t<_Tp>, decay_t<_Up>>);
|
|
|
635
|
|
|
636 /* FIXME:
|
|
|
637 if constexpr (floating_point<decay_t<_Tp>>)
|
|
|
638 return __cmp_cust::__fp_strong_order(__e, __f);
|
|
|
639 else */ if constexpr (__adl_strong<_Tp, _Up>)
|
|
|
640 return strong_ordering(strong_order(static_cast<_Tp&&>(__e),
|
|
|
641 static_cast<_Up&&>(__f)));
|
|
|
642 else if constexpr (__op_cmp<strong_ordering, _Tp, _Up>)
|
|
|
643 return static_cast<_Tp&&>(__e) <=> static_cast<_Up&&>(__f);
|
|
|
644 }
|
|
|
645 };
|
|
|
646
|
|
|
647 template<typename _Tp, typename _Up>
|
|
|
648 concept __weakly_ordered
|
|
|
649 = floating_point<remove_reference_t<_Tp>>
|
|
|
650 || __adl_weak<_Tp, _Up>
|
|
|
651 || __op_cmp<weak_ordering, _Tp, _Up>
|
|
|
652 || __strongly_ordered<_Tp, _Up>;
|
|
|
653
|
|
|
654 class _Weak_order
|
|
|
655 {
|
|
|
656 template<typename _Tp, typename _Up>
|
|
|
657 static constexpr bool
|
|
|
658 _S_noexcept()
|
|
|
659 {
|
|
|
660 if constexpr (floating_point<decay_t<_Tp>>)
|
|
|
661 return true;
|
|
|
662 else if constexpr (__adl_weak<_Tp, _Up>)
|
|
|
663 return noexcept(weak_ordering(weak_order(std::declval<_Tp>(),
|
|
|
664 std::declval<_Up>())));
|
|
|
665 else if constexpr (__op_cmp<weak_ordering, _Tp, _Up>)
|
|
|
666 return noexcept(std::declval<_Tp>() <=> std::declval<_Up>());
|
|
|
667 else if constexpr (__strongly_ordered<_Tp, _Up>)
|
|
|
668 return _Strong_order::_S_noexcept<_Tp, _Up>();
|
|
|
669 }
|
|
|
670
|
|
|
671 friend class _Partial_order;
|
|
|
672 friend class _Weak_fallback;
|
|
|
673
|
|
|
674 public:
|
|
|
675 template<typename _Tp, typename _Up>
|
|
|
676 requires __weakly_ordered<_Tp, _Up>
|
|
|
677 constexpr weak_ordering
|
|
|
678 operator()(_Tp&& __e, _Up&& __f) const
|
|
|
679 noexcept(_S_noexcept<_Tp, _Up>())
|
|
|
680 {
|
|
|
681 static_assert(same_as<decay_t<_Tp>, decay_t<_Up>>);
|
|
|
682
|
|
|
683 if constexpr (floating_point<decay_t<_Tp>>)
|
|
|
684 return __cmp_cust::__fp_weak_ordering(__e, __f);
|
|
|
685 else if constexpr (__adl_weak<_Tp, _Up>)
|
|
|
686 return weak_ordering(weak_order(static_cast<_Tp&&>(__e),
|
|
|
687 static_cast<_Up&&>(__f)));
|
|
|
688 else if constexpr (__op_cmp<weak_ordering, _Tp, _Up>)
|
|
|
689 return static_cast<_Tp&&>(__e) <=> static_cast<_Up&&>(__f);
|
|
|
690 else if constexpr (__strongly_ordered<_Tp, _Up>)
|
|
|
691 return _Strong_order{}(static_cast<_Tp&&>(__e),
|
|
|
692 static_cast<_Up&&>(__f));
|
|
|
693 }
|
|
|
694 };
|
|
|
695
|
|
|
696 template<typename _Tp, typename _Up>
|
|
|
697 concept __partially_ordered
|
|
|
698 = __adl_partial<_Tp, _Up>
|
|
|
699 || __op_cmp<partial_ordering, _Tp, _Up>
|
|
|
700 || __weakly_ordered<_Tp, _Up>;
|
|
|
701
|
|
|
702 class _Partial_order
|
|
|
703 {
|
|
|
704 template<typename _Tp, typename _Up>
|
|
|
705 static constexpr bool
|
|
|
706 _S_noexcept()
|
|
|
707 {
|
|
|
708 if constexpr (__adl_partial<_Tp, _Up>)
|
|
|
709 return noexcept(partial_ordering(partial_order(std::declval<_Tp>(),
|
|
|
710 std::declval<_Up>())));
|
|
|
711 else if constexpr (__op_cmp<partial_ordering, _Tp, _Up>)
|
|
|
712 return noexcept(std::declval<_Tp>() <=> std::declval<_Up>());
|
|
|
713 else if constexpr (__weakly_ordered<_Tp, _Up>)
|
|
|
714 return _Weak_order::_S_noexcept<_Tp, _Up>();
|
|
|
715 }
|
|
|
716
|
|
|
717 friend class _Partial_fallback;
|
|
|
718
|
|
|
719 public:
|
|
|
720 template<typename _Tp, typename _Up>
|
|
|
721 requires __partially_ordered<_Tp, _Up>
|
|
|
722 constexpr partial_ordering
|
|
|
723 operator()(_Tp&& __e, _Up&& __f) const
|
|
|
724 noexcept(_S_noexcept<_Tp, _Up>())
|
|
|
725 {
|
|
|
726 static_assert(same_as<decay_t<_Tp>, decay_t<_Up>>);
|
|
|
727
|
|
|
728 if constexpr (__adl_partial<_Tp, _Up>)
|
|
|
729 return partial_ordering(partial_order(static_cast<_Tp&&>(__e),
|
|
|
730 static_cast<_Up&&>(__f)));
|
|
|
731 else if constexpr (__op_cmp<partial_ordering, _Tp, _Up>)
|
|
|
732 return static_cast<_Tp&&>(__e) <=> static_cast<_Up&&>(__f);
|
|
|
733 else if constexpr (__weakly_ordered<_Tp, _Up>)
|
|
|
734 return _Weak_order{}(static_cast<_Tp&&>(__e),
|
|
|
735 static_cast<_Up&&>(__f));
|
|
|
736 }
|
|
|
737 };
|
|
|
738
|
|
|
739 template<typename _Tp, typename _Up>
|
|
|
740 concept __op_eq_lt = requires(_Tp&& __t, _Up&& __u)
|
|
|
741 {
|
|
|
742 { static_cast<_Tp&&>(__t) == static_cast<_Up&&>(__u) }
|
|
|
743 -> convertible_to<bool>;
|
|
|
744 { static_cast<_Tp&&>(__t) < static_cast<_Up&&>(__u) }
|
|
|
745 -> convertible_to<bool>;
|
|
|
746 };
|
|
|
747
|
|
|
748 class _Strong_fallback
|
|
|
749 {
|
|
|
750 template<typename _Tp, typename _Up>
|
|
|
751 static constexpr bool
|
|
|
752 _S_noexcept()
|
|
|
753 {
|
|
|
754 if constexpr (__strongly_ordered<_Tp, _Up>)
|
|
|
755 return _Strong_order::_S_noexcept<_Tp, _Up>();
|
|
|
756 else
|
|
|
757 return noexcept(bool(std::declval<_Tp>() == std::declval<_Up>()))
|
|
|
758 && noexcept(bool(std::declval<_Tp>() < std::declval<_Up>()));
|
|
|
759 }
|
|
|
760
|
|
|
761 public:
|
|
|
762 template<typename _Tp, typename _Up>
|
|
|
763 requires __strongly_ordered<_Tp, _Up> || __op_eq_lt<_Tp, _Up>
|
|
|
764 constexpr decltype(auto)
|
|
|
765 operator()(_Tp&& __e, _Up&& __f) const
|
|
|
766 noexcept(_S_noexcept<_Tp, _Up>())
|
|
|
767 {
|
|
|
768 static_assert(same_as<decay_t<_Tp>, decay_t<_Up>>);
|
|
|
769
|
|
|
770 if constexpr (__strongly_ordered<_Tp, _Up>)
|
|
|
771 return _Strong_order{}(static_cast<_Tp&&>(__e),
|
|
|
772 static_cast<_Up&&>(__f));
|
|
|
773 else if constexpr (__op_eq_lt<_Tp, _Up>)
|
|
|
774 return static_cast<_Tp&&>(__e) == static_cast<_Up&&>(__f)
|
|
|
775 ? strong_ordering::equal
|
|
|
776 : static_cast<_Tp&&>(__e) < static_cast<_Up&&>(__f)
|
|
|
777 ? strong_ordering::less
|
|
|
778 : strong_ordering::greater;
|
|
|
779 }
|
|
|
780 };
|
|
|
781
|
|
|
782 class _Weak_fallback
|
|
|
783 {
|
|
|
784 template<typename _Tp, typename _Up>
|
|
|
785 static constexpr bool
|
|
|
786 _S_noexcept()
|
|
|
787 {
|
|
|
788 if constexpr (__weakly_ordered<_Tp, _Up>)
|
|
|
789 return _Weak_order::_S_noexcept<_Tp, _Up>();
|
|
|
790 else
|
|
|
791 return noexcept(bool(std::declval<_Tp>() == std::declval<_Up>()))
|
|
|
792 && noexcept(bool(std::declval<_Tp>() < std::declval<_Up>()));
|
|
|
793 }
|
|
|
794
|
|
|
795 public:
|
|
|
796 template<typename _Tp, typename _Up>
|
|
|
797 requires __weakly_ordered<_Tp, _Up> || __op_eq_lt<_Tp, _Up>
|
|
|
798 constexpr decltype(auto)
|
|
|
799 operator()(_Tp&& __e, _Up&& __f) const
|
|
|
800 noexcept(_S_noexcept<_Tp, _Up>())
|
|
|
801 {
|
|
|
802 static_assert(same_as<decay_t<_Tp>, decay_t<_Up>>);
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|
|
803
|
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|
804 if constexpr (__weakly_ordered<_Tp, _Up>)
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|
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805 return _Weak_order{}(static_cast<_Tp&&>(__e),
|
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|
806 static_cast<_Up&&>(__f));
|
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|
807 else if constexpr (__op_eq_lt<_Tp, _Up>)
|
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|
808 return static_cast<_Tp&&>(__e) == static_cast<_Up&&>(__f)
|
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809 ? weak_ordering::equivalent
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|
810 : static_cast<_Tp&&>(__e) < static_cast<_Up&&>(__f)
|
|
|
811 ? weak_ordering::less
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812 : weak_ordering::greater;
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|
813 }
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814 };
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815
|
|
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816 class _Partial_fallback
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817 {
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|
818 template<typename _Tp, typename _Up>
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|
|
819 static constexpr bool
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|
820 _S_noexcept()
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|
821 {
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|
822 if constexpr (__partially_ordered<_Tp, _Up>)
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|
|
823 return _Partial_order::_S_noexcept<_Tp, _Up>();
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|
824 else
|
|
|
825 return noexcept(bool(std::declval<_Tp>() == std::declval<_Up>()))
|
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|
826 && noexcept(bool(std::declval<_Tp>() < std::declval<_Up>()));
|
|
|
827 }
|
|
|
828
|
|
|
829 public:
|
|
|
830 template<typename _Tp, typename _Up>
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|
|
831 requires __partially_ordered<_Tp, _Up> || __op_eq_lt<_Tp, _Up>
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|
|
832 constexpr decltype(auto)
|
|
|
833 operator()(_Tp&& __e, _Up&& __f) const
|
|
|
834 noexcept(_S_noexcept<_Tp, _Up>())
|
|
|
835 {
|
|
|
836 static_assert(same_as<decay_t<_Tp>, decay_t<_Up>>);
|
|
|
837
|
|
|
838 if constexpr (__partially_ordered<_Tp, _Up>)
|
|
|
839 return _Partial_order{}(static_cast<_Tp&&>(__e),
|
|
|
840 static_cast<_Up&&>(__f));
|
|
|
841 else if constexpr (__op_eq_lt<_Tp, _Up>)
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|
|
842 return static_cast<_Tp&&>(__e) == static_cast<_Up&&>(__f)
|
|
|
843 ? partial_ordering::equivalent
|
|
|
844 : static_cast<_Tp&&>(__e) < static_cast<_Up&&>(__f)
|
|
|
845 ? partial_ordering::less
|
|
|
846 : static_cast<_Up&&>(__f) < static_cast<_Tp&&>(__e)
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|
|
847 ? partial_ordering::greater
|
|
|
848 : partial_ordering::unordered;
|
|
|
849 }
|
|
|
850 };
|
|
|
851 } // namespace __cmp_cust
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|
|
852
|
|
|
853 // [cmp.alg], comparison algorithms
|
|
|
854 inline namespace __cmp_alg
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|
|
855 {
|
|
|
856 inline constexpr __cmp_cust::_Strong_order strong_order{};
|
|
|
857
|
|
|
858 inline constexpr __cmp_cust::_Weak_order weak_order{};
|
|
|
859
|
|
|
860 inline constexpr __cmp_cust::_Partial_order partial_order{};
|
|
|
861
|
|
|
862 inline constexpr __cmp_cust::_Strong_fallback
|
|
|
863 compare_strong_order_fallback{};
|
|
|
864
|
|
|
865 inline constexpr __cmp_cust::_Weak_fallback
|
|
|
866 compare_weak_order_fallback{};
|
|
|
867
|
|
|
868 inline constexpr __cmp_cust::_Partial_fallback
|
|
|
869 compare_partial_order_fallback{};
|
|
|
870 }
|
|
|
871
|
|
|
872 namespace __detail
|
|
|
873 {
|
|
|
874 // [expos.only.func]
|
|
|
875 inline constexpr struct _Synth3way
|
|
|
876 {
|
|
|
877 template<typename _Tp, typename _Up>
|
|
|
878 constexpr auto
|
|
|
879 operator()(const _Tp& __t, const _Up& __u) const
|
|
|
880 requires requires
|
|
|
881 {
|
|
|
882 { __t < __u } -> convertible_to<bool>;
|
|
|
883 { __u < __t } -> convertible_to<bool>;
|
|
|
884 }
|
|
|
885 {
|
|
|
886 if constexpr (three_way_comparable_with<_Tp, _Up>)
|
|
|
887 return __t <=> __u;
|
|
|
888 else
|
|
|
889 {
|
|
|
890 if (__t < __u)
|
|
|
891 return weak_ordering::less;
|
|
|
892 else if (__u < __t)
|
|
|
893 return weak_ordering::greater;
|
|
|
894 else
|
|
|
895 return weak_ordering::equivalent;
|
|
|
896 }
|
|
|
897 }
|
|
|
898 } __synth3way = {};
|
|
|
899
|
|
|
900 template<typename _Tp, typename _Up = _Tp>
|
|
|
901 using __synth3way_t
|
|
|
902 = decltype(__detail::__synth3way(std::declval<_Tp&>(),
|
|
|
903 std::declval<_Up&>()));
|
|
|
904 } // namespace __detail
|
|
|
905 #endif // concepts
|
|
|
906 } // namespace std
|
|
|
907
|
|
|
908 #pragma GCC visibility pop
|
|
|
909
|
|
|
910 #endif // C++20
|
|
|
911
|
|
|
912 #endif // _COMPARE
|
