1 // <utility> -*- C++ -*- 2 3 // Copyright (C) 2001-2021 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 /* 26 * 27 * Copyright (c) 1994 28 * Hewlett-Packard Company 29 * 30 * Permission to use, copy, modify, distribute and sell this software 31 * and its documentation for any purpose is hereby granted without fee, 32 * provided that the above copyright notice appear in all copies and 33 * that both that copyright notice and this permission notice appear 34 * in supporting documentation. Hewlett-Packard Company makes no 35 * representations about the suitability of this software for any 36 * purpose. It is provided "as is" without express or implied warranty. 37 * 38 * 39 * Copyright (c) 1996,1997 40 * Silicon Graphics Computer Systems, Inc. 41 * 42 * Permission to use, copy, modify, distribute and sell this software 43 * and its documentation for any purpose is hereby granted without fee, 44 * provided that the above copyright notice appear in all copies and 45 * that both that copyright notice and this permission notice appear 46 * in supporting documentation. Silicon Graphics makes no 47 * representations about the suitability of this software for any 48 * purpose. It is provided "as is" without express or implied warranty. 49 */ 50 51 /** @file include/utility 52 * This is a Standard C++ Library header. 53 */ 54 55 #ifndef _GLIBCXX_UTILITY 56 #define _GLIBCXX_UTILITY 1 57 58 #pragma GCC system_header 59 60 /** 61 * @defgroup utilities Utilities 62 * 63 * Components deemed generally useful. Includes pair, tuple, 64 * forward/move helpers, ratio, function object, metaprogramming and 65 * type traits, time, date, and memory functions. 66 */ 67 68 #include <bits/c++config.h> 69 #include <bits/stl_relops.h> 70 #include <bits/stl_pair.h> 71 72 #if __cplusplus >= 201103L 73 74 #include <type_traits> 75 #include <bits/move.h> 76 #include <initializer_list> 77 78 #if __cplusplus > 201703L 79 #include <ext/numeric_traits.h> 80 #endif 81 82 namespace std _GLIBCXX_VISIBILITY(default) 83 { 84 _GLIBCXX_BEGIN_NAMESPACE_VERSION 85 86 /// Finds the size of a given tuple type. 87 template<typename _Tp> 88 struct tuple_size; 89 90 // _GLIBCXX_RESOLVE_LIB_DEFECTS 91 // 2313. tuple_size should always derive from integral_constant<size_t, N> 92 // 2770. tuple_size<const T> specialization is not SFINAE compatible 93 94 template<typename _Tp, 95 typename _Up = typename remove_cv<_Tp>::type, 96 typename = typename enable_if<is_same<_Tp, _Up>::value>::type, 97 size_t = tuple_size<_Tp>::value> 98 using __enable_if_has_tuple_size = _Tp; 99 100 template<typename _Tp> 101 struct tuple_size<const __enable_if_has_tuple_size<_Tp>> 102 : public tuple_size<_Tp> { }; 103 104 template<typename _Tp> 105 struct tuple_size<volatile __enable_if_has_tuple_size<_Tp>> 106 : public tuple_size<_Tp> { }; 107 108 template<typename _Tp> 109 struct tuple_size<const volatile __enable_if_has_tuple_size<_Tp>> 110 : public tuple_size<_Tp> { }; 111 112 /// Gives the type of the ith element of a given tuple type. 113 template<size_t __i, typename _Tp> 114 struct tuple_element; 115 116 // Duplicate of C++14's tuple_element_t for internal use in C++11 mode 117 template<size_t __i, typename _Tp> 118 using __tuple_element_t = typename tuple_element<__i, _Tp>::type; 119 120 template<size_t __i, typename _Tp> 121 struct tuple_element<__i, const _Tp> 122 { 123 typedef typename add_const<__tuple_element_t<__i, _Tp>>::type type; 124 }; 125 126 template<size_t __i, typename _Tp> 127 struct tuple_element<__i, volatile _Tp> 128 { 129 typedef typename add_volatile<__tuple_element_t<__i, _Tp>>::type type; 130 }; 131 132 template<size_t __i, typename _Tp> 133 struct tuple_element<__i, const volatile _Tp> 134 { 135 typedef typename add_cv<__tuple_element_t<__i, _Tp>>::type type; 136 }; 137 138 #if __cplusplus >= 201402L 139 // The standard says this macro and alias template should be in <tuple> 140 // but we define them here, to be available when the partial specializations 141 // of tuple_element<pair<T,U>> and tuple_element<array<T,N>> are defined. 142 #define __cpp_lib_tuple_element_t 201402L 143 144 template<size_t __i, typename _Tp> 145 using tuple_element_t = typename tuple_element<__i, _Tp>::type; 146 #endif 147 148 // Various functions which give std::pair a tuple-like interface. 149 150 /// Partial specialization for std::pair 151 template<typename _T1, typename _T2> 152 struct __is_tuple_like_impl<pair<_T1, _T2>> : true_type 153 { }; 154 155 /// Partial specialization for std::pair 156 template<class _Tp1, class _Tp2> 157 struct tuple_size<pair<_Tp1, _Tp2>> 158 : public integral_constant<size_t, 2> { }; 159 160 /// Partial specialization for std::pair 161 template<class _Tp1, class _Tp2> 162 struct tuple_element<0, pair<_Tp1, _Tp2>> 163 { typedef _Tp1 type; }; 164 165 /// Partial specialization for std::pair 166 template<class _Tp1, class _Tp2> 167 struct tuple_element<1, pair<_Tp1, _Tp2>> 168 { typedef _Tp2 type; }; 169 170 template<size_t _Int> 171 struct __pair_get; 172 173 template<> 174 struct __pair_get<0> 175 { 176 template<typename _Tp1, typename _Tp2> 177 static constexpr _Tp1& 178 __get(pair<_Tp1, _Tp2>& __pair) noexcept 179 { return __pair.first; } 180 181 template<typename _Tp1, typename _Tp2> 182 static constexpr _Tp1&& 183 __move_get(pair<_Tp1, _Tp2>&& __pair) noexcept 184 { return std::forward<_Tp1>(__pair.first); } 185 186 template<typename _Tp1, typename _Tp2> 187 static constexpr const _Tp1& 188 __const_get(const pair<_Tp1, _Tp2>& __pair) noexcept 189 { return __pair.first; } 190 191 template<typename _Tp1, typename _Tp2> 192 static constexpr const _Tp1&& 193 __const_move_get(const pair<_Tp1, _Tp2>&& __pair) noexcept 194 { return std::forward<const _Tp1>(__pair.first); } 195 }; 196 197 template<> 198 struct __pair_get<1> 199 { 200 template<typename _Tp1, typename _Tp2> 201 static constexpr _Tp2& 202 __get(pair<_Tp1, _Tp2>& __pair) noexcept 203 { return __pair.second; } 204 205 template<typename _Tp1, typename _Tp2> 206 static constexpr _Tp2&& 207 __move_get(pair<_Tp1, _Tp2>&& __pair) noexcept 208 { return std::forward<_Tp2>(__pair.second); } 209 210 template<typename _Tp1, typename _Tp2> 211 static constexpr const _Tp2& 212 __const_get(const pair<_Tp1, _Tp2>& __pair) noexcept 213 { return __pair.second; } 214 215 template<typename _Tp1, typename _Tp2> 216 static constexpr const _Tp2&& 217 __const_move_get(const pair<_Tp1, _Tp2>&& __pair) noexcept 218 { return std::forward<const _Tp2>(__pair.second); } 219 }; 220 221 template<size_t _Int, class _Tp1, class _Tp2> 222 constexpr typename tuple_element<_Int, pair<_Tp1, _Tp2>>::type& 223 get(pair<_Tp1, _Tp2>& __in) noexcept 224 { return __pair_get<_Int>::__get(__in); } 225 226 template<size_t _Int, class _Tp1, class _Tp2> 227 constexpr typename tuple_element<_Int, pair<_Tp1, _Tp2>>::type&& 228 get(pair<_Tp1, _Tp2>&& __in) noexcept 229 { return __pair_get<_Int>::__move_get(std::move(__in)); } 230 231 template<size_t _Int, class _Tp1, class _Tp2> 232 constexpr const typename tuple_element<_Int, pair<_Tp1, _Tp2>>::type& 233 get(const pair<_Tp1, _Tp2>& __in) noexcept 234 { return __pair_get<_Int>::__const_get(__in); } 235 236 template<size_t _Int, class _Tp1, class _Tp2> 237 constexpr const typename tuple_element<_Int, pair<_Tp1, _Tp2>>::type&& 238 get(const pair<_Tp1, _Tp2>&& __in) noexcept 239 { return __pair_get<_Int>::__const_move_get(std::move(__in)); } 240 241 #if __cplusplus >= 201402L 242 243 #define __cpp_lib_tuples_by_type 201304 244 245 template <typename _Tp, typename _Up> 246 constexpr _Tp& 247 get(pair<_Tp, _Up>& __p) noexcept 248 { return __p.first; } 249 250 template <typename _Tp, typename _Up> 251 constexpr const _Tp& 252 get(const pair<_Tp, _Up>& __p) noexcept 253 { return __p.first; } 254 255 template <typename _Tp, typename _Up> 256 constexpr _Tp&& 257 get(pair<_Tp, _Up>&& __p) noexcept 258 { return std::move(__p.first); } 259 260 template <typename _Tp, typename _Up> 261 constexpr const _Tp&& 262 get(const pair<_Tp, _Up>&& __p) noexcept 263 { return std::move(__p.first); } 264 265 template <typename _Tp, typename _Up> 266 constexpr _Tp& 267 get(pair<_Up, _Tp>& __p) noexcept 268 { return __p.second; } 269 270 template <typename _Tp, typename _Up> 271 constexpr const _Tp& 272 get(const pair<_Up, _Tp>& __p) noexcept 273 { return __p.second; } 274 275 template <typename _Tp, typename _Up> 276 constexpr _Tp&& 277 get(pair<_Up, _Tp>&& __p) noexcept 278 { return std::move(__p.second); } 279 280 template <typename _Tp, typename _Up> 281 constexpr const _Tp&& 282 get(const pair<_Up, _Tp>&& __p) noexcept 283 { return std::move(__p.second); } 284 285 #define __cpp_lib_exchange_function 201304 286 287 /// Assign @p __new_val to @p __obj and return its previous value. 288 template <typename _Tp, typename _Up = _Tp> 289 _GLIBCXX20_CONSTEXPR 290 inline _Tp 291 exchange(_Tp& __obj, _Up&& __new_val) 292 { return std::__exchange(__obj, std::forward<_Up>(__new_val)); } 293 294 #endif // C++14 295 296 // Stores a tuple of indices. Used by tuple and pair, and by bind() to 297 // extract the elements in a tuple. 298 template<size_t... _Indexes> struct _Index_tuple { }; 299 300 // Builds an _Index_tuple<0, 1, 2, ..., _Num-1>. 301 template<size_t _Num> 302 struct _Build_index_tuple 303 { 304 #if __has_builtin(__make_integer_seq) 305 template<typename, size_t... _Indices> 306 using _IdxTuple = _Index_tuple<_Indices...>; 307 308 // Clang defines __make_integer_seq for this purpose. 309 using __type = __make_integer_seq<_IdxTuple, size_t, _Num>; 310 #else 311 // For GCC and other compilers, use __integer_pack instead. 312 using __type = _Index_tuple<__integer_pack(_Num)...>; 313 #endif 314 }; 315 316 #if __cplusplus >= 201402L 317 318 #define __cpp_lib_integer_sequence 201304 319 320 /// Class template integer_sequence 321 template<typename _Tp, _Tp... _Idx> 322 struct integer_sequence 323 { 324 typedef _Tp value_type; 325 static constexpr size_t size() noexcept { return sizeof...(_Idx); } 326 }; 327 328 /// Alias template make_integer_sequence 329 template<typename _Tp, _Tp _Num> 330 using make_integer_sequence 331 #if __has_builtin(__make_integer_seq) 332 = __make_integer_seq<integer_sequence, _Tp, _Num>; 333 #else 334 = integer_sequence<_Tp, __integer_pack(_Num)...>; 335 #endif 336 337 /// Alias template index_sequence 338 template<size_t... _Idx> 339 using index_sequence = integer_sequence<size_t, _Idx...>; 340 341 /// Alias template make_index_sequence 342 template<size_t _Num> 343 using make_index_sequence = make_integer_sequence<size_t, _Num>; 344 345 /// Alias template index_sequence_for 346 template<typename... _Types> 347 using index_sequence_for = make_index_sequence<sizeof...(_Types)>; 348 #endif 349 350 #if __cplusplus > 201402L 351 352 struct in_place_t { 353 explicit in_place_t() = default; 354 }; 355 356 inline constexpr in_place_t in_place{}; 357 358 template<typename _Tp> struct in_place_type_t 359 { 360 explicit in_place_type_t() = default; 361 }; 362 363 template<typename _Tp> 364 inline constexpr in_place_type_t<_Tp> in_place_type{}; 365 366 template<size_t _Idx> struct in_place_index_t 367 { 368 explicit in_place_index_t() = default; 369 }; 370 371 template<size_t _Idx> 372 inline constexpr in_place_index_t<_Idx> in_place_index{}; 373 374 template<typename> 375 struct __is_in_place_type_impl : false_type 376 { }; 377 378 template<typename _Tp> 379 struct __is_in_place_type_impl<in_place_type_t<_Tp>> : true_type 380 { }; 381 382 template<typename _Tp> 383 struct __is_in_place_type 384 : public __is_in_place_type_impl<_Tp> 385 { }; 386 387 #define __cpp_lib_as_const 201510 388 template<typename _Tp> 389 [[nodiscard]] 390 constexpr add_const_t<_Tp>& 391 as_const(_Tp& __t) noexcept 392 { return __t; } 393 394 template<typename _Tp> 395 void as_const(const _Tp&&) = delete; 396 397 #if __cplusplus > 201703L 398 #define __cpp_lib_integer_comparison_functions 202002L 399 400 template<typename _Tp, typename _Up> 401 constexpr bool 402 cmp_equal(_Tp __t, _Up __u) noexcept 403 { 404 static_assert(__is_standard_integer<_Tp>::value); 405 static_assert(__is_standard_integer<_Up>::value); 406 407 if constexpr (is_signed_v<_Tp> == is_signed_v<_Up>) 408 return __t == __u; 409 else if constexpr (is_signed_v<_Tp>) 410 return __t >= 0 && make_unsigned_t<_Tp>(__t) == __u; 411 else 412 return __u >= 0 && __t == make_unsigned_t<_Up>(__u); 413 } 414 415 template<typename _Tp, typename _Up> 416 constexpr bool 417 cmp_not_equal(_Tp __t, _Up __u) noexcept 418 { return !std::cmp_equal(__t, __u); } 419 420 template<typename _Tp, typename _Up> 421 constexpr bool 422 cmp_less(_Tp __t, _Up __u) noexcept 423 { 424 static_assert(__is_standard_integer<_Tp>::value); 425 static_assert(__is_standard_integer<_Up>::value); 426 427 if constexpr (is_signed_v<_Tp> == is_signed_v<_Up>) 428 return __t < __u; 429 else if constexpr (is_signed_v<_Tp>) 430 return __t < 0 || make_unsigned_t<_Tp>(__t) < __u; 431 else 432 return __u >= 0 && __t < make_unsigned_t<_Up>(__u); 433 } 434 435 template<typename _Tp, typename _Up> 436 constexpr bool 437 cmp_greater(_Tp __t, _Up __u) noexcept 438 { return std::cmp_less(__u, __t); } 439 440 template<typename _Tp, typename _Up> 441 constexpr bool 442 cmp_less_equal(_Tp __t, _Up __u) noexcept 443 { return !std::cmp_less(__u, __t); } 444 445 template<typename _Tp, typename _Up> 446 constexpr bool 447 cmp_greater_equal(_Tp __t, _Up __u) noexcept 448 { return !std::cmp_less(__t, __u); } 449 450 template<typename _Up, typename _Tp> 451 constexpr bool 452 in_range(_Tp __t) noexcept 453 { 454 static_assert(__is_standard_integer<_Up>::value); 455 static_assert(__is_standard_integer<_Tp>::value); 456 using __gnu_cxx::__int_traits; 457 458 if constexpr (is_signed_v<_Tp> == is_signed_v<_Up>) 459 return __int_traits<_Up>::__min <= __t 460 && __t <= __int_traits<_Up>::__max; 461 else if constexpr (is_signed_v<_Tp>) 462 return __t >= 0 463 && make_unsigned_t<_Tp>(__t) <= __int_traits<_Up>::__max; 464 else 465 return __t <= make_unsigned_t<_Up>(__int_traits<_Up>::__max); 466 } 467 468 #if __cplusplus > 202002L 469 #define __cpp_lib_to_underlying 202102L 470 /// Convert an object of enumeration type to its underlying type. 471 template<typename _Tp> 472 [[nodiscard]] 473 constexpr underlying_type_t<_Tp> 474 to_underlying(_Tp __value) noexcept 475 { return static_cast<underlying_type_t<_Tp>>(__value); } 476 #endif // C++23 477 #endif // C++20 478 #endif // C++17 479 480 _GLIBCXX_END_NAMESPACE_VERSION 481 } // namespace 482 483 #endif 484 485 #endif /* _GLIBCXX_UTILITY */ 486