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The C and C++ Include Header Files
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1 // Range access functions for containers -*- C++ -*- 2 3 // Copyright (C) 2010-2025 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 bits/range_access.h 26 * This is an internal header file, included by other library headers. 27 * Do not attempt to use it directly. @headername{iterator} 28 */ 29 30 #ifndef _GLIBCXX_RANGE_ACCESS_H 31 #define _GLIBCXX_RANGE_ACCESS_H 1 32 33 #ifdef _GLIBCXX_SYSHDR 34 #pragma GCC system_header 35 #endif 36 37 #if __cplusplus >= 201103L 38 #include <initializer_list> 39 #include <type_traits> // common_type_t, make_signed_t 40 #include <bits/stl_iterator.h> // reverse_iterator 41 42 namespace std _GLIBCXX_VISIBILITY(default) 43 { 44 _GLIBCXX_BEGIN_NAMESPACE_VERSION 45 46 /** 47 * @brief Return an iterator pointing to the first element of 48 * the container. 49 * @param __cont Container. 50 */ 51 template<typename _Container> 52 [[__nodiscard__, __gnu__::__always_inline__]] 53 inline _GLIBCXX17_CONSTEXPR auto 54 begin(_Container& __cont) noexcept(noexcept(__cont.begin())) 55 -> decltype(__cont.begin()) 56 { return __cont.begin(); } 57 58 /** 59 * @brief Return an iterator pointing to the first element of 60 * the const container. 61 * @param __cont Container. 62 */ 63 template<typename _Container> 64 [[__nodiscard__, __gnu__::__always_inline__]] 65 inline _GLIBCXX17_CONSTEXPR auto 66 begin(const _Container& __cont) noexcept(noexcept(__cont.begin())) 67 -> decltype(__cont.begin()) 68 { return __cont.begin(); } 69 70 /** 71 * @brief Return an iterator pointing to one past the last element of 72 * the container. 73 * @param __cont Container. 74 */ 75 template<typename _Container> 76 [[__nodiscard__, __gnu__::__always_inline__]] 77 inline _GLIBCXX17_CONSTEXPR auto 78 end(_Container& __cont) noexcept(noexcept(__cont.end())) 79 -> decltype(__cont.end()) 80 { return __cont.end(); } 81 82 /** 83 * @brief Return an iterator pointing to one past the last element of 84 * the const container. 85 * @param __cont Container. 86 */ 87 template<typename _Container> 88 [[__nodiscard__, __gnu__::__always_inline__]] 89 inline _GLIBCXX17_CONSTEXPR auto 90 end(const _Container& __cont) noexcept(noexcept(__cont.end())) 91 -> decltype(__cont.end()) 92 { return __cont.end(); } 93 94 /** 95 * @brief Return an iterator pointing to the first element of the array. 96 * @param __arr Array. 97 */ 98 template<typename _Tp, size_t _Nm> 99 [[__nodiscard__, __gnu__::__always_inline__]] 100 inline _GLIBCXX14_CONSTEXPR _Tp* 101 begin(_Tp (&__arr)[_Nm]) noexcept 102 { return __arr; } 103 104 /** 105 * @brief Return an iterator pointing to one past the last element 106 * of the array. 107 * @param __arr Array. 108 */ 109 template<typename _Tp, size_t _Nm> 110 [[__nodiscard__, __gnu__::__always_inline__]] 111 inline _GLIBCXX14_CONSTEXPR _Tp* 112 end(_Tp (&__arr)[_Nm]) noexcept 113 { return __arr + _Nm; } 114 115 #if __cplusplus >= 201402L 116 117 template<typename _Tp> class valarray; 118 // These overloads must be declared for cbegin and cend to use them. 119 template<typename _Tp> _Tp* begin(valarray<_Tp>&) noexcept; 120 template<typename _Tp> const _Tp* begin(const valarray<_Tp>&) noexcept; 121 template<typename _Tp> _Tp* end(valarray<_Tp>&) noexcept; 122 template<typename _Tp> const _Tp* end(const valarray<_Tp>&) noexcept; 123 124 /** 125 * @brief Return an iterator pointing to the first element of 126 * the const container. 127 * @param __cont Container. 128 */ 129 template<typename _Container> 130 [[__nodiscard__, __gnu__::__always_inline__]] 131 constexpr auto 132 cbegin(const _Container& __cont) noexcept(noexcept(std::begin(__cont))) 133 -> decltype(std::begin(__cont)) 134 { return std::begin(__cont); } 135 136 /** 137 * @brief Return an iterator pointing to one past the last element of 138 * the const container. 139 * @param __cont Container. 140 */ 141 template<typename _Container> 142 [[__nodiscard__, __gnu__::__always_inline__]] 143 constexpr auto 144 cend(const _Container& __cont) noexcept(noexcept(std::end(__cont))) 145 -> decltype(std::end(__cont)) 146 { return std::end(__cont); } 147 148 /** 149 * @brief Return a reverse iterator pointing to the last element of 150 * the container. 151 * @param __cont Container. 152 */ 153 template<typename _Container> 154 [[__nodiscard__, __gnu__::__always_inline__]] 155 inline _GLIBCXX17_CONSTEXPR auto 156 rbegin(_Container& __cont) noexcept(noexcept(__cont.rbegin())) 157 -> decltype(__cont.rbegin()) 158 { return __cont.rbegin(); } 159 160 /** 161 * @brief Return a reverse iterator pointing to the last element of 162 * the const container. 163 * @param __cont Container. 164 */ 165 template<typename _Container> 166 [[__nodiscard__, __gnu__::__always_inline__]] 167 inline _GLIBCXX17_CONSTEXPR auto 168 rbegin(const _Container& __cont) noexcept(noexcept(__cont.rbegin())) 169 -> decltype(__cont.rbegin()) 170 { return __cont.rbegin(); } 171 172 /** 173 * @brief Return a reverse iterator pointing one past the first element of 174 * the container. 175 * @param __cont Container. 176 */ 177 template<typename _Container> 178 [[__nodiscard__, __gnu__::__always_inline__]] 179 inline _GLIBCXX17_CONSTEXPR auto 180 rend(_Container& __cont) noexcept(noexcept(__cont.rend())) 181 -> decltype(__cont.rend()) 182 { return __cont.rend(); } 183 184 /** 185 * @brief Return a reverse iterator pointing one past the first element of 186 * the const container. 187 * @param __cont Container. 188 */ 189 template<typename _Container> 190 [[__nodiscard__, __gnu__::__always_inline__]] 191 inline _GLIBCXX17_CONSTEXPR auto 192 rend(const _Container& __cont) noexcept(noexcept(__cont.rend())) 193 -> decltype(__cont.rend()) 194 { return __cont.rend(); } 195 196 /** 197 * @brief Return a reverse iterator pointing to the last element of 198 * the array. 199 * @param __arr Array. 200 */ 201 template<typename _Tp, size_t _Nm> 202 [[__nodiscard__]] 203 inline _GLIBCXX17_CONSTEXPR reverse_iterator<_Tp*> 204 rbegin(_Tp (&__arr)[_Nm]) noexcept 205 { return reverse_iterator<_Tp*>(__arr + _Nm); } 206 207 /** 208 * @brief Return a reverse iterator pointing one past the first element of 209 * the array. 210 * @param __arr Array. 211 */ 212 template<typename _Tp, size_t _Nm> 213 [[__nodiscard__]] 214 inline _GLIBCXX17_CONSTEXPR reverse_iterator<_Tp*> 215 rend(_Tp (&__arr)[_Nm]) noexcept 216 { return reverse_iterator<_Tp*>(__arr); } 217 218 /** 219 * @brief Return a reverse iterator pointing to the last element of 220 * the initializer_list. 221 * @param __il initializer_list. 222 */ 223 template<typename _Tp> 224 [[__nodiscard__]] 225 inline _GLIBCXX17_CONSTEXPR reverse_iterator<const _Tp*> 226 rbegin(initializer_list<_Tp> __il) noexcept 227 { return reverse_iterator<const _Tp*>(__il.end()); } 228 229 /** 230 * @brief Return a reverse iterator pointing one past the first element of 231 * the initializer_list. 232 * @param __il initializer_list. 233 */ 234 template<typename _Tp> 235 [[__nodiscard__]] 236 inline _GLIBCXX17_CONSTEXPR reverse_iterator<const _Tp*> 237 rend(initializer_list<_Tp> __il) noexcept 238 { return reverse_iterator<const _Tp*>(__il.begin()); } 239 240 /** 241 * @brief Return a reverse iterator pointing to the last element of 242 * the const container. 243 * @param __cont Container. 244 */ 245 template<typename _Container> 246 [[__nodiscard__, __gnu__::__always_inline__]] 247 inline _GLIBCXX17_CONSTEXPR auto 248 crbegin(const _Container& __cont) noexcept(noexcept(std::rbegin(__cont))) 249 -> decltype(std::rbegin(__cont)) 250 { return std::rbegin(__cont); } 251 252 /** 253 * @brief Return a reverse iterator pointing one past the first element of 254 * the const container. 255 * @param __cont Container. 256 */ 257 template<typename _Container> 258 [[__nodiscard__, __gnu__::__always_inline__]] 259 inline _GLIBCXX17_CONSTEXPR auto 260 crend(const _Container& __cont) noexcept(noexcept(std::rend(__cont))) 261 -> decltype(std::rend(__cont)) 262 { return std::rend(__cont); } 263 264 #endif // C++14 265 266 #ifdef __glibcxx_nonmember_container_access // C++ >= 17 267 /** 268 * @brief Return the size of a container. 269 * @param __cont Container. 270 */ 271 template <typename _Container> 272 [[nodiscard, __gnu__::__always_inline__]] 273 constexpr auto 274 size(const _Container& __cont) noexcept(noexcept(__cont.size())) 275 -> decltype(__cont.size()) 276 { return __cont.size(); } 277 278 /** 279 * @brief Return the size of an array. 280 */ 281 template <typename _Tp, size_t _Nm> 282 [[nodiscard, __gnu__::__always_inline__]] 283 constexpr size_t 284 size(const _Tp (&)[_Nm]) noexcept 285 { return _Nm; } 286 287 /** 288 * @brief Return whether a container is empty. 289 * @param __cont Container. 290 */ 291 template <typename _Container> 292 [[nodiscard, __gnu__::__always_inline__]] 293 constexpr auto 294 empty(const _Container& __cont) noexcept(noexcept(__cont.empty())) 295 -> decltype(__cont.empty()) 296 { return __cont.empty(); } 297 298 /** 299 * @brief Return whether an array is empty (always false). 300 */ 301 template <typename _Tp, size_t _Nm> 302 [[nodiscard, __gnu__::__always_inline__]] 303 constexpr bool 304 empty(const _Tp (&)[_Nm]) noexcept 305 { return false; } 306 307 /** 308 * @brief Return whether an initializer_list is empty. 309 * @param __il Initializer list. 310 */ 311 template <typename _Tp> 312 [[nodiscard, __gnu__::__always_inline__]] 313 constexpr bool 314 empty(initializer_list<_Tp> __il) noexcept 315 { return __il.size() == 0;} 316 317 /** 318 * @brief Return the data pointer of a container. 319 * @param __cont Container. 320 */ 321 template <typename _Container> 322 [[nodiscard, __gnu__::__always_inline__]] 323 constexpr auto 324 data(_Container& __cont) noexcept(noexcept(__cont.data())) 325 -> decltype(__cont.data()) 326 { return __cont.data(); } 327 328 /** 329 * @brief Return the data pointer of a const container. 330 * @param __cont Container. 331 */ 332 template <typename _Container> 333 [[nodiscard, __gnu__::__always_inline__]] 334 constexpr auto 335 data(const _Container& __cont) noexcept(noexcept(__cont.data())) 336 -> decltype(__cont.data()) 337 { return __cont.data(); } 338 339 /** 340 * @brief Return the data pointer of an array. 341 * @param __array Array. 342 */ 343 template <typename _Tp, size_t _Nm> 344 [[nodiscard, __gnu__::__always_inline__]] 345 constexpr _Tp* 346 data(_Tp (&__array)[_Nm]) noexcept 347 { return __array; } 348 349 /** 350 * @brief Return the data pointer of an initializer list. 351 * @param __il Initializer list. 352 */ 353 template <typename _Tp> 354 [[nodiscard, __gnu__::__always_inline__]] 355 constexpr const _Tp* 356 data(initializer_list<_Tp> __il) noexcept 357 { return __il.begin(); } 358 #endif // __glibcxx_nonmember_container_access 359 360 #ifdef __glibcxx_ssize // C++ >= 20 361 template<typename _Container> 362 [[nodiscard, __gnu__::__always_inline__]] 363 constexpr auto 364 ssize(const _Container& __cont) noexcept(noexcept(__cont.size())) 365 -> common_type_t<ptrdiff_t, make_signed_t<decltype(__cont.size())>> 366 { 367 using type = make_signed_t<decltype(__cont.size())>; 368 return static_cast<common_type_t<ptrdiff_t, type>>(__cont.size()); 369 } 370 371 template<typename _Tp, ptrdiff_t _Num> 372 [[nodiscard, __gnu__::__always_inline__]] 373 constexpr ptrdiff_t 374 ssize(const _Tp (&)[_Num]) noexcept 375 { return _Num; } 376 #endif // __glibcxx_ssize 377 _GLIBCXX_END_NAMESPACE_VERSION 378 } // namespace 379 380 #endif // C++11 381 #endif // _GLIBCXX_RANGE_ACCESS_H
