1 // <concepts> -*- C++ -*- 2 3 // Copyright (C) 2019-2022 Free Software Foundation, Inc. 4 // 5 // This file is part of the GNU ISO C++ Library. This library is free 6 // software; you can redistribute it and/or modify it under the 7 // terms of the GNU General Public License as published by the 8 // Free Software Foundation; either version 3, or (at your option) 9 // any later version. 10 11 // This library is distributed in the hope that it will be useful, 12 // but WITHOUT ANY WARRANTY; without even the implied warranty of 13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 // GNU General Public License for more details. 15 16 // Under Section 7 of GPL version 3, you are granted additional 17 // permissions described in the GCC Runtime Library Exception, version 18 // 3.1, as published by the Free Software Foundation. 19 20 // You should have received a copy of the GNU General Public License and 21 // a copy of the GCC Runtime Library Exception along with this program; 22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 23 // <http://www.gnu.org/licenses/>. 24 25 /** @file include/concepts 26 * This is a Standard C++ Library header. 27 * @ingroup concepts 28 */ 29 30 #ifndef _GLIBCXX_CONCEPTS 31 #define _GLIBCXX_CONCEPTS 1 32 33 #if __cplusplus > 201703L && __cpp_concepts >= 201907L 34 35 #pragma GCC system_header 36 37 /** 38 * @defgroup concepts Concepts 39 * @ingroup utilities 40 * 41 * Concepts for checking type requirements. 42 */ 43 44 #include <type_traits> 45 46 namespace std _GLIBCXX_VISIBILITY(default) 47 { 48 _GLIBCXX_BEGIN_NAMESPACE_VERSION 49 50 #define __cpp_lib_concepts 202002L 51 52 // [concepts.lang], language-related concepts 53 54 namespace __detail 55 { 56 template<typename _Tp, typename _Up> 57 concept __same_as = std::is_same_v<_Tp, _Up>; 58 } // namespace __detail 59 60 /// [concept.same], concept same_as 61 template<typename _Tp, typename _Up> 62 concept same_as 63 = __detail::__same_as<_Tp, _Up> && __detail::__same_as<_Up, _Tp>; 64 65 /// [concept.derived], concept derived_from 66 template<typename _Derived, typename _Base> 67 concept derived_from = __is_base_of(_Base, _Derived) 68 && is_convertible_v<const volatile _Derived*, const volatile _Base*>; 69 70 /// [concept.convertible], concept convertible_to 71 template<typename _From, typename _To> 72 concept convertible_to = is_convertible_v<_From, _To> 73 && requires { static_cast<_To>(std::declval<_From>()); }; 74 75 /// [concept.commonref], concept common_reference_with 76 template<typename _Tp, typename _Up> 77 concept common_reference_with 78 = same_as<common_reference_t<_Tp, _Up>, common_reference_t<_Up, _Tp>> 79 && convertible_to<_Tp, common_reference_t<_Tp, _Up>> 80 && convertible_to<_Up, common_reference_t<_Tp, _Up>>; 81 82 /// [concept.common], concept common_with 83 template<typename _Tp, typename _Up> 84 concept common_with 85 = same_as<common_type_t<_Tp, _Up>, common_type_t<_Up, _Tp>> 86 && requires { 87 static_cast<common_type_t<_Tp, _Up>>(std::declval<_Tp>()); 88 static_cast<common_type_t<_Tp, _Up>>(std::declval<_Up>()); 89 } 90 && common_reference_with<add_lvalue_reference_t<const _Tp>, 91 add_lvalue_reference_t<const _Up>> 92 && common_reference_with<add_lvalue_reference_t<common_type_t<_Tp, _Up>>, 93 common_reference_t< 94 add_lvalue_reference_t<const _Tp>, 95 add_lvalue_reference_t<const _Up>>>; 96 97 // [concepts.arithmetic], arithmetic concepts 98 99 template<typename _Tp> 100 concept integral = is_integral_v<_Tp>; 101 102 template<typename _Tp> 103 concept signed_integral = integral<_Tp> && is_signed_v<_Tp>; 104 105 template<typename _Tp> 106 concept unsigned_integral = integral<_Tp> && !signed_integral<_Tp>; 107 108 template<typename _Tp> 109 concept floating_point = is_floating_point_v<_Tp>; 110 111 namespace __detail 112 { 113 template<typename _Tp> 114 using __cref = const remove_reference_t<_Tp>&; 115 116 template<typename _Tp> 117 concept __class_or_enum 118 = is_class_v<_Tp> || is_union_v<_Tp> || is_enum_v<_Tp>; 119 } // namespace __detail 120 121 /// [concept.assignable], concept assignable_from 122 template<typename _Lhs, typename _Rhs> 123 concept assignable_from 124 = is_lvalue_reference_v<_Lhs> 125 && common_reference_with<__detail::__cref<_Lhs>, __detail::__cref<_Rhs>> 126 && requires(_Lhs __lhs, _Rhs&& __rhs) { 127 { __lhs = static_cast<_Rhs&&>(__rhs) } -> same_as<_Lhs>; 128 }; 129 130 /// [concept.destructible], concept destructible 131 template<typename _Tp> 132 concept destructible = is_nothrow_destructible_v<_Tp>; 133 134 /// [concept.constructible], concept constructible_from 135 template<typename _Tp, typename... _Args> 136 concept constructible_from 137 = destructible<_Tp> && is_constructible_v<_Tp, _Args...>; 138 139 /// [concept.defaultinitializable], concept default_initializable 140 template<typename _Tp> 141 concept default_initializable = constructible_from<_Tp> 142 && requires 143 { 144 _Tp{}; 145 (void) ::new _Tp; 146 }; 147 148 /// [concept.moveconstructible], concept move_constructible 149 template<typename _Tp> 150 concept move_constructible 151 = constructible_from<_Tp, _Tp> && convertible_to<_Tp, _Tp>; 152 153 /// [concept.copyconstructible], concept copy_constructible 154 template<typename _Tp> 155 concept copy_constructible 156 = move_constructible<_Tp> 157 && constructible_from<_Tp, _Tp&> && convertible_to<_Tp&, _Tp> 158 && constructible_from<_Tp, const _Tp&> && convertible_to<const _Tp&, _Tp> 159 && constructible_from<_Tp, const _Tp> && convertible_to<const _Tp, _Tp>; 160 161 // [concept.swappable], concept swappable 162 163 namespace ranges 164 { 165 namespace __cust_swap 166 { 167 template<typename _Tp> void swap(_Tp&, _Tp&) = delete; 168 169 template<typename _Tp, typename _Up> 170 concept __adl_swap 171 = (__detail::__class_or_enum<remove_reference_t<_Tp>> 172 || __detail::__class_or_enum<remove_reference_t<_Up>>) 173 && requires(_Tp&& __t, _Up&& __u) { 174 swap(static_cast<_Tp&&>(__t), static_cast<_Up&&>(__u)); 175 }; 176 177 struct _Swap 178 { 179 private: 180 template<typename _Tp, typename _Up> 181 static constexpr bool 182 _S_noexcept() 183 { 184 if constexpr (__adl_swap<_Tp, _Up>) 185 return noexcept(swap(std::declval<_Tp>(), std::declval<_Up>())); 186 else 187 return is_nothrow_move_constructible_v<remove_reference_t<_Tp>> 188 && is_nothrow_move_assignable_v<remove_reference_t<_Tp>>; 189 } 190 191 public: 192 template<typename _Tp, typename _Up> 193 requires __adl_swap<_Tp, _Up> 194 || (same_as<_Tp, _Up> && is_lvalue_reference_v<_Tp> 195 && move_constructible<remove_reference_t<_Tp>> 196 && assignable_from<_Tp, remove_reference_t<_Tp>>) 197 constexpr void 198 operator()(_Tp&& __t, _Up&& __u) const 199 noexcept(_S_noexcept<_Tp, _Up>()) 200 { 201 if constexpr (__adl_swap<_Tp, _Up>) 202 swap(static_cast<_Tp&&>(__t), static_cast<_Up&&>(__u)); 203 else 204 { 205 auto __tmp = static_cast<remove_reference_t<_Tp>&&>(__t); 206 __t = static_cast<remove_reference_t<_Tp>&&>(__u); 207 __u = static_cast<remove_reference_t<_Tp>&&>(__tmp); 208 } 209 } 210 211 template<typename _Tp, typename _Up, size_t _Num> 212 requires requires(const _Swap& __swap, _Tp& __e1, _Up& __e2) { 213 __swap(__e1, __e2); 214 } 215 constexpr void 216 operator()(_Tp (&__e1)[_Num], _Up (&__e2)[_Num]) const 217 noexcept(noexcept(std::declval<const _Swap&>()(*__e1, *__e2))) 218 { 219 for (size_t __n = 0; __n < _Num; ++__n) 220 (*this)(__e1[__n], __e2[__n]); 221 } 222 }; 223 } // namespace __cust_swap 224 225 inline namespace __cust 226 { 227 inline constexpr __cust_swap::_Swap swap{}; 228 } // inline namespace __cust 229 } // namespace ranges 230 231 template<typename _Tp> 232 concept swappable 233 = requires(_Tp& __a, _Tp& __b) { ranges::swap(__a, __b); }; 234 235 template<typename _Tp, typename _Up> 236 concept swappable_with = common_reference_with<_Tp, _Up> 237 && requires(_Tp&& __t, _Up&& __u) { 238 ranges::swap(static_cast<_Tp&&>(__t), static_cast<_Tp&&>(__t)); 239 ranges::swap(static_cast<_Up&&>(__u), static_cast<_Up&&>(__u)); 240 ranges::swap(static_cast<_Tp&&>(__t), static_cast<_Up&&>(__u)); 241 ranges::swap(static_cast<_Up&&>(__u), static_cast<_Tp&&>(__t)); 242 }; 243 244 // [concepts.object], Object concepts 245 246 template<typename _Tp> 247 concept movable = is_object_v<_Tp> && move_constructible<_Tp> 248 && assignable_from<_Tp&, _Tp> && swappable<_Tp>; 249 250 template<typename _Tp> 251 concept copyable = copy_constructible<_Tp> && movable<_Tp> 252 && assignable_from<_Tp&, _Tp&> && assignable_from<_Tp&, const _Tp&> 253 && assignable_from<_Tp&, const _Tp>; 254 255 template<typename _Tp> 256 concept semiregular = copyable<_Tp> && default_initializable<_Tp>; 257 258 // [concepts.compare], comparison concepts 259 260 // [concept.booleantestable], Boolean testability 261 namespace __detail 262 { 263 template<typename _Tp> 264 concept __boolean_testable_impl = convertible_to<_Tp, bool>; 265 266 template<typename _Tp> 267 concept __boolean_testable 268 = __boolean_testable_impl<_Tp> 269 && requires(_Tp&& __t) 270 { { !static_cast<_Tp&&>(__t) } -> __boolean_testable_impl; }; 271 } // namespace __detail 272 273 // [concept.equalitycomparable], concept equality_comparable 274 275 namespace __detail 276 { 277 template<typename _Tp, typename _Up> 278 concept __weakly_eq_cmp_with 279 = requires(__detail::__cref<_Tp> __t, __detail::__cref<_Up> __u) { 280 { __t == __u } -> __boolean_testable; 281 { __t != __u } -> __boolean_testable; 282 { __u == __t } -> __boolean_testable; 283 { __u != __t } -> __boolean_testable; 284 }; 285 } // namespace __detail 286 287 template<typename _Tp> 288 concept equality_comparable = __detail::__weakly_eq_cmp_with<_Tp, _Tp>; 289 290 template<typename _Tp, typename _Up> 291 concept equality_comparable_with 292 = equality_comparable<_Tp> && equality_comparable<_Up> 293 && common_reference_with<__detail::__cref<_Tp>, __detail::__cref<_Up>> 294 && equality_comparable<common_reference_t<__detail::__cref<_Tp>, 295 __detail::__cref<_Up>>> 296 && __detail::__weakly_eq_cmp_with<_Tp, _Up>; 297 298 namespace __detail 299 { 300 template<typename _Tp, typename _Up> 301 concept __partially_ordered_with 302 = requires(const remove_reference_t<_Tp>& __t, 303 const remove_reference_t<_Up>& __u) { 304 { __t < __u } -> __boolean_testable; 305 { __t > __u } -> __boolean_testable; 306 { __t <= __u } -> __boolean_testable; 307 { __t >= __u } -> __boolean_testable; 308 { __u < __t } -> __boolean_testable; 309 { __u > __t } -> __boolean_testable; 310 { __u <= __t } -> __boolean_testable; 311 { __u >= __t } -> __boolean_testable; 312 }; 313 } // namespace __detail 314 315 // [concept.totallyordered], concept totally_ordered 316 template<typename _Tp> 317 concept totally_ordered 318 = equality_comparable<_Tp> 319 && __detail::__partially_ordered_with<_Tp, _Tp>; 320 321 template<typename _Tp, typename _Up> 322 concept totally_ordered_with 323 = totally_ordered<_Tp> && totally_ordered<_Up> 324 && equality_comparable_with<_Tp, _Up> 325 && totally_ordered<common_reference_t<__detail::__cref<_Tp>, 326 __detail::__cref<_Up>>> 327 && __detail::__partially_ordered_with<_Tp, _Up>; 328 329 template<typename _Tp> 330 concept regular = semiregular<_Tp> && equality_comparable<_Tp>; 331 332 // [concepts.callable], callable concepts 333 334 /// [concept.invocable], concept invocable 335 template<typename _Fn, typename... _Args> 336 concept invocable = is_invocable_v<_Fn, _Args...>; 337 338 /// [concept.regularinvocable], concept regular_invocable 339 template<typename _Fn, typename... _Args> 340 concept regular_invocable = invocable<_Fn, _Args...>; 341 342 /// [concept.predicate], concept predicate 343 template<typename _Fn, typename... _Args> 344 concept predicate = regular_invocable<_Fn, _Args...> 345 && __detail::__boolean_testable<invoke_result_t<_Fn, _Args...>>; 346 347 /// [concept.relation], concept relation 348 template<typename _Rel, typename _Tp, typename _Up> 349 concept relation 350 = predicate<_Rel, _Tp, _Tp> && predicate<_Rel, _Up, _Up> 351 && predicate<_Rel, _Tp, _Up> && predicate<_Rel, _Up, _Tp>; 352 353 /// [concept.equiv], concept equivalence_relation 354 template<typename _Rel, typename _Tp, typename _Up> 355 concept equivalence_relation = relation<_Rel, _Tp, _Up>; 356 357 /// [concept.strictweakorder], concept strict_weak_order 358 template<typename _Rel, typename _Tp, typename _Up> 359 concept strict_weak_order = relation<_Rel, _Tp, _Up>; 360 361 _GLIBCXX_END_NAMESPACE_VERSION 362 } // namespace 363 #endif // C++2a 364 365 #endif /* _GLIBCXX_CONCEPTS */ 366
Indexes created Mon Oct 26 00:26:21 UTC 2026