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1 // Deque implementation -*- C++ -*- 2 3 // Copyright (C) 2001-2025 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 /* 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) 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 bits/stl_deque.h 52 * This is an internal header file, included by other library headers. 53 * Do not attempt to use it directly. @headername{deque} 54 */ 55 56 #ifndef _STL_DEQUE_H 57 #define _STL_DEQUE_H 1 58 59 #include <bits/concept_check.h> 60 #include <bits/stl_iterator_base_types.h> 61 #include <bits/stl_iterator_base_funcs.h> 62 #if __cplusplus >= 201103L 63 #include <initializer_list> 64 #include <bits/stl_uninitialized.h> // for __is_bitwise_relocatable 65 #endif 66 #if __cplusplus > 201703L 67 # include <compare> 68 #endif 69 #if __cplusplus > 202002L 70 # include <bits/ranges_algobase.h> // ranges::copy 71 #endif 72 73 #include <debug/assertions.h> 74 75 namespace std _GLIBCXX_VISIBILITY(default) 76 { 77 _GLIBCXX_BEGIN_NAMESPACE_VERSION 78 _GLIBCXX_BEGIN_NAMESPACE_CONTAINER 79 80 /** 81 * @brief This function controls the size of memory nodes. 82 * @param __size The size of an element. 83 * @return The number (not byte size) of elements per node. 84 * 85 * This function started off as a compiler kludge from SGI, but 86 * seems to be a useful wrapper around a repeated constant 87 * expression. The @b 512 is tunable (and no other code needs to 88 * change), but no investigation has been done since inheriting the 89 * SGI code. Touch _GLIBCXX_DEQUE_BUF_SIZE only if you know what 90 * you are doing, however: changing it breaks the binary 91 * compatibility!! 92 */ 93 94 #ifndef _GLIBCXX_DEQUE_BUF_SIZE 95 #define _GLIBCXX_DEQUE_BUF_SIZE 512 96 #endif 97 98 _GLIBCXX_CONSTEXPR inline size_t 99 __deque_buf_size(size_t __size) 100 { return (__size < _GLIBCXX_DEQUE_BUF_SIZE 101 ? size_t(_GLIBCXX_DEQUE_BUF_SIZE / __size) : size_t(1)); } 102 103 104 /** 105 * @brief A deque::iterator. 106 * 107 * Quite a bit of intelligence here. Much of the functionality of 108 * deque is actually passed off to this class. A deque holds two 109 * of these internally, marking its valid range. Access to 110 * elements is done as offsets of either of those two, relying on 111 * operator overloading in this class. 112 * 113 * All the functions are op overloads except for _M_set_node. 114 */ 115 template<typename _Tp, typename _Ref, typename _Ptr> 116 struct _Deque_iterator 117 { 118 #if __cplusplus < 201103L 119 typedef _Deque_iterator<_Tp, _Tp&, _Tp*> iterator; 120 typedef _Deque_iterator<_Tp, const _Tp&, const _Tp*> const_iterator; 121 typedef _Tp* _Elt_pointer; 122 typedef _Tp** _Map_pointer; 123 #else 124 private: 125 template<typename _CvTp> 126 using __iter = _Deque_iterator<_Tp, _CvTp&, __ptr_rebind<_Ptr, _CvTp>>; 127 public: 128 typedef __iter<_Tp> iterator; 129 typedef __iter<const _Tp> const_iterator; 130 typedef __ptr_rebind<_Ptr, _Tp> _Elt_pointer; 131 typedef __ptr_rebind<_Ptr, _Elt_pointer> _Map_pointer; 132 #endif 133 134 static size_t _S_buffer_size() _GLIBCXX_NOEXCEPT 135 { return __deque_buf_size(sizeof(_Tp)); } 136 137 typedef std::random_access_iterator_tag iterator_category; 138 typedef _Tp value_type; 139 typedef _Ptr pointer; 140 typedef _Ref reference; 141 typedef size_t size_type; 142 typedef ptrdiff_t difference_type; 143 typedef _Deque_iterator _Self; 144 145 _Elt_pointer _M_cur; 146 _Elt_pointer _M_first; 147 _Elt_pointer _M_last; 148 _Map_pointer _M_node; 149 150 _Deque_iterator(_Elt_pointer __x, _Map_pointer __y) _GLIBCXX_NOEXCEPT 151 : _M_cur(__x), _M_first(*__y), 152 _M_last(*__y + _S_buffer_size()), _M_node(__y) { } 153 154 _Deque_iterator() _GLIBCXX_NOEXCEPT 155 : _M_cur(), _M_first(), _M_last(), _M_node() { } 156 157 #if __cplusplus < 201103L 158 // Conversion from iterator to const_iterator. 159 _Deque_iterator(const iterator& __x) _GLIBCXX_NOEXCEPT 160 : _M_cur(__x._M_cur), _M_first(__x._M_first), 161 _M_last(__x._M_last), _M_node(__x._M_node) { } 162 #else 163 // Conversion from iterator to const_iterator. 164 template<typename _Iter, 165 typename = _Require<is_same<_Self, const_iterator>, 166 is_same<_Iter, iterator>>> 167 _Deque_iterator(const _Iter& __x) noexcept 168 : _M_cur(__x._M_cur), _M_first(__x._M_first), 169 _M_last(__x._M_last), _M_node(__x._M_node) { } 170 171 _Deque_iterator(const _Deque_iterator& __x) noexcept 172 : _M_cur(__x._M_cur), _M_first(__x._M_first), 173 _M_last(__x._M_last), _M_node(__x._M_node) { } 174 175 _Deque_iterator& operator=(const _Deque_iterator&) = default; 176 #endif 177 178 iterator 179 _M_const_cast() const _GLIBCXX_NOEXCEPT 180 { return iterator(_M_cur, _M_node); } 181 182 _GLIBCXX_NODISCARD 183 reference 184 operator*() const _GLIBCXX_NOEXCEPT 185 { return *_M_cur; } 186 187 _GLIBCXX_NODISCARD 188 pointer 189 operator->() const _GLIBCXX_NOEXCEPT 190 { return _M_cur; } 191 192 _Self& 193 operator++() _GLIBCXX_NOEXCEPT 194 { 195 ++_M_cur; 196 if (_M_cur == _M_last) 197 { 198 _M_set_node(_M_node + 1); 199 _M_cur = _M_first; 200 } 201 return *this; 202 } 203 204 _Self 205 operator++(int) _GLIBCXX_NOEXCEPT 206 { 207 _Self __tmp = *this; 208 ++*this; 209 return __tmp; 210 } 211 212 _Self& 213 operator--() _GLIBCXX_NOEXCEPT 214 { 215 if (_M_cur == _M_first) 216 { 217 _M_set_node(_M_node - 1); 218 _M_cur = _M_last; 219 } 220 --_M_cur; 221 return *this; 222 } 223 224 _Self 225 operator--(int) _GLIBCXX_NOEXCEPT 226 { 227 _Self __tmp = *this; 228 --*this; 229 return __tmp; 230 } 231 232 _Self& 233 operator+=(difference_type __n) _GLIBCXX_NOEXCEPT 234 { 235 const difference_type __offset = __n + (_M_cur - _M_first); 236 if (__offset >= 0 && __offset < difference_type(_S_buffer_size())) 237 _M_cur += __n; 238 else 239 { 240 const difference_type __node_offset = 241 __offset > 0 ? __offset / difference_type(_S_buffer_size()) 242 : -difference_type((-__offset - 1) 243 / _S_buffer_size()) - 1; 244 _M_set_node(_M_node + __node_offset); 245 _M_cur = _M_first + (__offset - __node_offset 246 * difference_type(_S_buffer_size())); 247 } 248 return *this; 249 } 250 251 _Self& 252 operator-=(difference_type __n) _GLIBCXX_NOEXCEPT 253 { return *this += -__n; } 254 255 _GLIBCXX_NODISCARD 256 reference 257 operator[](difference_type __n) const _GLIBCXX_NOEXCEPT 258 { return *(*this + __n); } 259 260 /** 261 * Prepares to traverse new_node. Sets everything except 262 * _M_cur, which should therefore be set by the caller 263 * immediately afterwards, based on _M_first and _M_last. 264 */ 265 void 266 _M_set_node(_Map_pointer __new_node) _GLIBCXX_NOEXCEPT 267 { 268 _M_node = __new_node; 269 _M_first = *__new_node; 270 _M_last = _M_first + difference_type(_S_buffer_size()); 271 } 272 273 _GLIBCXX_NODISCARD 274 friend bool 275 operator==(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT 276 { return __x._M_cur == __y._M_cur; } 277 278 // Note: we also provide overloads whose operands are of the same type in 279 // order to avoid ambiguous overload resolution when std::rel_ops 280 // operators are in scope (for additional details, see libstdc++/3628) 281 template<typename _RefR, typename _PtrR> 282 _GLIBCXX_NODISCARD 283 friend bool 284 operator==(const _Self& __x, 285 const _Deque_iterator<_Tp, _RefR, _PtrR>& __y) 286 _GLIBCXX_NOEXCEPT 287 { return __x._M_cur == __y._M_cur; } 288 289 #if __cpp_lib_three_way_comparison 290 [[nodiscard]] 291 friend strong_ordering 292 operator<=>(const _Self& __x, const _Self& __y) noexcept 293 { 294 if (const auto __cmp = __x._M_node <=> __y._M_node; __cmp != 0) 295 return __cmp; 296 return __x._M_cur <=> __y._M_cur; 297 } 298 #else 299 _GLIBCXX_NODISCARD 300 friend bool 301 operator!=(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT 302 { return !(__x == __y); } 303 304 template<typename _RefR, typename _PtrR> 305 _GLIBCXX_NODISCARD 306 friend bool 307 operator!=(const _Self& __x, 308 const _Deque_iterator<_Tp, _RefR, _PtrR>& __y) 309 _GLIBCXX_NOEXCEPT 310 { return !(__x == __y); } 311 312 _GLIBCXX_NODISCARD 313 friend bool 314 operator<(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT 315 { 316 return (__x._M_node == __y._M_node) 317 ? (__x._M_cur < __y._M_cur) : (__x._M_node < __y._M_node); 318 } 319 320 template<typename _RefR, typename _PtrR> 321 _GLIBCXX_NODISCARD 322 friend bool 323 operator<(const _Self& __x, 324 const _Deque_iterator<_Tp, _RefR, _PtrR>& __y) 325 _GLIBCXX_NOEXCEPT 326 { 327 return (__x._M_node == __y._M_node) 328 ? (__x._M_cur < __y._M_cur) : (__x._M_node < __y._M_node); 329 } 330 331 _GLIBCXX_NODISCARD 332 friend bool 333 operator>(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT 334 { return __y < __x; } 335 336 template<typename _RefR, typename _PtrR> 337 _GLIBCXX_NODISCARD 338 friend bool 339 operator>(const _Self& __x, 340 const _Deque_iterator<_Tp, _RefR, _PtrR>& __y) 341 _GLIBCXX_NOEXCEPT 342 { return __y < __x; } 343 344 _GLIBCXX_NODISCARD 345 friend bool 346 operator<=(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT 347 { return !(__y < __x); } 348 349 template<typename _RefR, typename _PtrR> 350 _GLIBCXX_NODISCARD 351 friend bool 352 operator<=(const _Self& __x, 353 const _Deque_iterator<_Tp, _RefR, _PtrR>& __y) 354 _GLIBCXX_NOEXCEPT 355 { return !(__y < __x); } 356 357 _GLIBCXX_NODISCARD 358 friend bool 359 operator>=(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT 360 { return !(__x < __y); } 361 362 template<typename _RefR, typename _PtrR> 363 _GLIBCXX_NODISCARD 364 friend bool 365 operator>=(const _Self& __x, 366 const _Deque_iterator<_Tp, _RefR, _PtrR>& __y) 367 _GLIBCXX_NOEXCEPT 368 { return !(__x < __y); } 369 #endif // three-way comparison 370 371 _GLIBCXX_NODISCARD 372 friend difference_type 373 operator-(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT 374 { 375 return difference_type(_S_buffer_size()) 376 * (__x._M_node - __y._M_node - bool(__x._M_node)) 377 + (__x._M_cur - __x._M_first) 378 + (__y._M_last - __y._M_cur); 379 } 380 381 // _GLIBCXX_RESOLVE_LIB_DEFECTS 382 // According to the resolution of DR179 not only the various comparison 383 // operators but also operator- must accept mixed iterator/const_iterator 384 // parameters. 385 template<typename _RefR, typename _PtrR> 386 _GLIBCXX_NODISCARD 387 friend difference_type 388 operator-(const _Self& __x, 389 const _Deque_iterator<_Tp, _RefR, _PtrR>& __y) 390 _GLIBCXX_NOEXCEPT 391 { 392 return difference_type(_S_buffer_size()) 393 * (__x._M_node - __y._M_node - bool(__x._M_node)) 394 + (__x._M_cur - __x._M_first) 395 + (__y._M_last - __y._M_cur); 396 } 397 398 _GLIBCXX_NODISCARD 399 friend _Self 400 operator+(const _Self& __x, difference_type __n) _GLIBCXX_NOEXCEPT 401 { 402 _Self __tmp = __x; 403 __tmp += __n; 404 return __tmp; 405 } 406 407 _GLIBCXX_NODISCARD 408 friend _Self 409 operator-(const _Self& __x, difference_type __n) _GLIBCXX_NOEXCEPT 410 { 411 _Self __tmp = __x; 412 __tmp -= __n; 413 return __tmp; 414 } 415 416 _GLIBCXX_NODISCARD 417 friend _Self 418 operator+(difference_type __n, const _Self& __x) _GLIBCXX_NOEXCEPT 419 { return __x + __n; } 420 }; 421 422 /** 423 * Deque base class. This class provides the unified face for %deque's 424 * allocation. This class's constructor and destructor allocate and 425 * deallocate (but do not initialize) storage. This makes %exception 426 * safety easier. 427 * 428 * Nothing in this class ever constructs or destroys an actual Tp element. 429 * (Deque handles that itself.) Only/All memory management is performed 430 * here. 431 */ 432 template<typename _Tp, typename _Alloc> 433 class _Deque_base 434 { 435 protected: 436 typedef typename __gnu_cxx::__alloc_traits<_Alloc>::template 437 rebind<_Tp>::other _Tp_alloc_type; 438 typedef __gnu_cxx::__alloc_traits<_Tp_alloc_type> _Alloc_traits; 439 440 #if __cplusplus < 201103L 441 typedef _Tp* _Ptr; 442 typedef const _Tp* _Ptr_const; 443 #else 444 typedef typename _Alloc_traits::pointer _Ptr; 445 typedef typename _Alloc_traits::const_pointer _Ptr_const; 446 #endif 447 448 typedef typename _Alloc_traits::template rebind<_Ptr>::other 449 _Map_alloc_type; 450 typedef __gnu_cxx::__alloc_traits<_Map_alloc_type> _Map_alloc_traits; 451 452 typedef _Alloc allocator_type; 453 454 allocator_type 455 get_allocator() const _GLIBCXX_NOEXCEPT 456 { return allocator_type(_M_get_Tp_allocator()); } 457 458 typedef _Deque_iterator<_Tp, _Tp&, _Ptr> iterator; 459 typedef _Deque_iterator<_Tp, const _Tp&, _Ptr_const> const_iterator; 460 461 _Deque_base() 462 : _M_impl() 463 { _M_initialize_map(0); } 464 465 _Deque_base(size_t __num_elements) 466 : _M_impl() 467 { _M_initialize_map(__num_elements); } 468 469 _Deque_base(const allocator_type& __a, size_t __num_elements) 470 : _M_impl(__a) 471 { _M_initialize_map(__num_elements); } 472 473 _Deque_base(const allocator_type& __a) 474 : _M_impl(__a) 475 { /* Caller must initialize map. */ } 476 477 #if __cplusplus >= 201103L 478 _Deque_base(_Deque_base&& __x) 479 : _M_impl(std::move(__x._M_get_Tp_allocator())) 480 { 481 _M_initialize_map(0); 482 if (__x._M_impl._M_map) 483 this->_M_impl._M_swap_data(__x._M_impl); 484 } 485 486 _Deque_base(_Deque_base&& __x, const allocator_type& __a) 487 : _M_impl(std::move(__x._M_impl), _Tp_alloc_type(__a)) 488 { __x._M_initialize_map(0); } 489 490 _Deque_base(_Deque_base&& __x, const allocator_type& __a, size_t __n) 491 : _M_impl(__a) 492 { 493 if (__x.get_allocator() == __a) 494 { 495 if (__x._M_impl._M_map) 496 { 497 _M_initialize_map(0); 498 this->_M_impl._M_swap_data(__x._M_impl); 499 } 500 } 501 else 502 { 503 _M_initialize_map(__n); 504 } 505 } 506 #endif 507 508 ~_Deque_base() _GLIBCXX_NOEXCEPT; 509 510 typedef typename iterator::_Map_pointer _Map_pointer; 511 512 struct _Deque_impl_data 513 { 514 _Map_pointer _M_map; 515 size_t _M_map_size; 516 iterator _M_start; 517 iterator _M_finish; 518 519 _Deque_impl_data() _GLIBCXX_NOEXCEPT 520 : _M_map(), _M_map_size(), _M_start(), _M_finish() 521 { } 522 523 #if __cplusplus >= 201103L 524 _Deque_impl_data(const _Deque_impl_data&) = default; 525 _Deque_impl_data& 526 operator=(const _Deque_impl_data&) = default; 527 528 _Deque_impl_data(_Deque_impl_data&& __x) noexcept 529 : _Deque_impl_data(__x) 530 { __x = _Deque_impl_data(); } 531 #endif 532 533 void 534 _M_swap_data(_Deque_impl_data& __x) _GLIBCXX_NOEXCEPT 535 { 536 // Do not use std::swap(_M_start, __x._M_start), etc as it loses 537 // information used by TBAA. 538 std::swap(*this, __x); 539 } 540 }; 541 542 // This struct encapsulates the implementation of the std::deque 543 // standard container and at the same time makes use of the EBO 544 // for empty allocators. 545 struct _Deque_impl 546 : public _Tp_alloc_type, public _Deque_impl_data 547 { 548 _Deque_impl() _GLIBCXX_NOEXCEPT_IF( 549 is_nothrow_default_constructible<_Tp_alloc_type>::value) 550 : _Tp_alloc_type() 551 { } 552 553 _Deque_impl(const _Tp_alloc_type& __a) _GLIBCXX_NOEXCEPT 554 : _Tp_alloc_type(__a) 555 { } 556 557 #if __cplusplus >= 201103L 558 _Deque_impl(_Deque_impl&&) = default; 559 560 _Deque_impl(_Tp_alloc_type&& __a) noexcept 561 : _Tp_alloc_type(std::move(__a)) 562 { } 563 564 _Deque_impl(_Deque_impl&& __d, _Tp_alloc_type&& __a) 565 : _Tp_alloc_type(std::move(__a)), _Deque_impl_data(std::move(__d)) 566 { } 567 #endif 568 }; 569 570 _Tp_alloc_type& 571 _M_get_Tp_allocator() _GLIBCXX_NOEXCEPT 572 { return this->_M_impl; } 573 574 const _Tp_alloc_type& 575 _M_get_Tp_allocator() const _GLIBCXX_NOEXCEPT 576 { return this->_M_impl; } 577 578 _Map_alloc_type 579 _M_get_map_allocator() const _GLIBCXX_NOEXCEPT 580 { return _Map_alloc_type(_M_get_Tp_allocator()); } 581 582 _Ptr 583 _M_allocate_node() 584 { 585 typedef __gnu_cxx::__alloc_traits<_Tp_alloc_type> _Traits; 586 return _Traits::allocate(_M_impl, __deque_buf_size(sizeof(_Tp))); 587 } 588 589 void 590 _M_deallocate_node(_Ptr __p) _GLIBCXX_NOEXCEPT 591 { 592 typedef __gnu_cxx::__alloc_traits<_Tp_alloc_type> _Traits; 593 _Traits::deallocate(_M_impl, __p, __deque_buf_size(sizeof(_Tp))); 594 } 595 596 _Map_pointer 597 _M_allocate_map(size_t __n) 598 { 599 _Map_alloc_type __map_alloc = _M_get_map_allocator(); 600 return _Map_alloc_traits::allocate(__map_alloc, __n); 601 } 602 603 void 604 _M_deallocate_map(_Map_pointer __p, size_t __n) _GLIBCXX_NOEXCEPT 605 { 606 _Map_alloc_type __map_alloc = _M_get_map_allocator(); 607 _Map_alloc_traits::deallocate(__map_alloc, __p, __n); 608 } 609 610 void _M_initialize_map(size_t); 611 void _M_create_nodes(_Map_pointer __nstart, _Map_pointer __nfinish); 612 void _M_destroy_nodes(_Map_pointer __nstart, 613 _Map_pointer __nfinish) _GLIBCXX_NOEXCEPT; 614 enum { _S_initial_map_size = 8 }; 615 616 _Deque_impl _M_impl; 617 }; 618 619 template<typename _Tp, typename _Alloc> 620 _Deque_base<_Tp, _Alloc>:: 621 ~_Deque_base() _GLIBCXX_NOEXCEPT 622 { 623 if (this->_M_impl._M_map) 624 { 625 _M_destroy_nodes(this->_M_impl._M_start._M_node, 626 this->_M_impl._M_finish._M_node + 1); 627 _M_deallocate_map(this->_M_impl._M_map, this->_M_impl._M_map_size); 628 } 629 } 630 631 /** 632 * @brief Layout storage. 633 * @param __num_elements The count of T's for which to allocate space 634 * at first. 635 * @return Nothing. 636 * 637 * The initial underlying memory layout is a bit complicated... 638 */ 639 template<typename _Tp, typename _Alloc> 640 void 641 _Deque_base<_Tp, _Alloc>:: 642 _M_initialize_map(size_t __num_elements) 643 { 644 const size_t __num_nodes = (__num_elements / __deque_buf_size(sizeof(_Tp)) 645 + 1); 646 647 this->_M_impl._M_map_size = std::max((size_t) _S_initial_map_size, 648 size_t(__num_nodes + 2)); 649 this->_M_impl._M_map = _M_allocate_map(this->_M_impl._M_map_size); 650 651 // For "small" maps (needing less than _M_map_size nodes), allocation 652 // starts in the middle elements and grows outwards. So nstart may be 653 // the beginning of _M_map, but for small maps it may be as far in as 654 // _M_map+3. 655 656 _Map_pointer __nstart = (this->_M_impl._M_map 657 + (this->_M_impl._M_map_size - __num_nodes) / 2); 658 _Map_pointer __nfinish = __nstart + __num_nodes; 659 660 __try 661 { _M_create_nodes(__nstart, __nfinish); } 662 __catch(...) 663 { 664 _M_deallocate_map(this->_M_impl._M_map, this->_M_impl._M_map_size); 665 this->_M_impl._M_map = _Map_pointer(); 666 this->_M_impl._M_map_size = 0; 667 __throw_exception_again; 668 } 669 670 this->_M_impl._M_start._M_set_node(__nstart); 671 this->_M_impl._M_finish._M_set_node(__nfinish - 1); 672 this->_M_impl._M_start._M_cur = _M_impl._M_start._M_first; 673 this->_M_impl._M_finish._M_cur = (this->_M_impl._M_finish._M_first 674 + __num_elements 675 % __deque_buf_size(sizeof(_Tp))); 676 } 677 678 template<typename _Tp, typename _Alloc> 679 void 680 _Deque_base<_Tp, _Alloc>:: 681 _M_create_nodes(_Map_pointer __nstart, _Map_pointer __nfinish) 682 { 683 _Map_pointer __cur; 684 __try 685 { 686 for (__cur = __nstart; __cur < __nfinish; ++__cur) 687 *__cur = this->_M_allocate_node(); 688 } 689 __catch(...) 690 { 691 _M_destroy_nodes(__nstart, __cur); 692 __throw_exception_again; 693 } 694 } 695 696 template<typename _Tp, typename _Alloc> 697 void 698 _Deque_base<_Tp, _Alloc>:: 699 _M_destroy_nodes(_Map_pointer __nstart, 700 _Map_pointer __nfinish) _GLIBCXX_NOEXCEPT 701 { 702 for (_Map_pointer __n = __nstart; __n < __nfinish; ++__n) 703 _M_deallocate_node(*__n); 704 } 705 706 /** 707 * @brief A standard container using fixed-size memory allocation and 708 * constant-time manipulation of elements at either end. 709 * 710 * @ingroup sequences 711 * 712 * @tparam _Tp Type of element. 713 * @tparam _Alloc Allocator type, defaults to allocator<_Tp>. 714 * 715 * Meets the requirements of a <a href="tables.html#65">container</a>, a 716 * <a href="tables.html#66">reversible container</a>, and a 717 * <a href="tables.html#67">sequence</a>, including the 718 * <a href="tables.html#68">optional sequence requirements</a>. 719 * 720 * In previous HP/SGI versions of deque, there was an extra template 721 * parameter so users could control the node size. This extension turned 722 * out to violate the C++ standard (it can be detected using template 723 * template parameters), and it was removed. 724 * 725 * Here's how a deque<Tp> manages memory. Each deque has 4 members: 726 * 727 * - Tp** _M_map 728 * - size_t _M_map_size 729 * - iterator _M_start, _M_finish 730 * 731 * map_size is at least 8. %map is an array of map_size 732 * pointers-to-@a nodes. (The name %map has nothing to do with the 733 * std::map class, and @b nodes should not be confused with 734 * std::list's usage of @a node.) 735 * 736 * A @a node has no specific type name as such, but it is referred 737 * to as @a node in this file. It is a simple array-of-Tp. If Tp 738 * is very large, there will be one Tp element per node (i.e., an 739 * @a array of one). For non-huge Tp's, node size is inversely 740 * related to Tp size: the larger the Tp, the fewer Tp's will fit 741 * in a node. The goal here is to keep the total size of a node 742 * relatively small and constant over different Tp's, to improve 743 * allocator efficiency. 744 * 745 * Not every pointer in the %map array will point to a node. If 746 * the initial number of elements in the deque is small, the 747 * /middle/ %map pointers will be valid, and the ones at the edges 748 * will be unused. This same situation will arise as the %map 749 * grows: available %map pointers, if any, will be on the ends. As 750 * new nodes are created, only a subset of the %map's pointers need 751 * to be copied @a outward. 752 * 753 * Class invariants: 754 * - For any nonsingular iterator i: 755 * - i.node points to a member of the %map array. (Yes, you read that 756 * correctly: i.node does not actually point to a node.) The member of 757 * the %map array is what actually points to the node. 758 * - i.first == *(i.node) (This points to the node (first Tp element).) 759 * - i.last == i.first + node_size 760 * - i.cur is a pointer in the range [i.first, i.last). NOTE: 761 * the implication of this is that i.cur is always a dereferenceable 762 * pointer, even if i is a past-the-end iterator. 763 * - Start and Finish are always nonsingular iterators. NOTE: this 764 * means that an empty deque must have one node, a deque with <N 765 * elements (where N is the node buffer size) must have one node, a 766 * deque with N through (2N-1) elements must have two nodes, etc. 767 * - For every node other than start.node and finish.node, every 768 * element in the node is an initialized object. If start.node == 769 * finish.node, then [start.cur, finish.cur) are initialized 770 * objects, and the elements outside that range are uninitialized 771 * storage. Otherwise, [start.cur, start.last) and [finish.first, 772 * finish.cur) are initialized objects, and [start.first, start.cur) 773 * and [finish.cur, finish.last) are uninitialized storage. 774 * - [%map, %map + map_size) is a valid, non-empty range. 775 * - [start.node, finish.node] is a valid range contained within 776 * [%map, %map + map_size). 777 * - A pointer in the range [%map, %map + map_size) points to an allocated 778 * node if and only if the pointer is in the range 779 * [start.node, finish.node]. 780 * 781 * Here's the magic: nothing in deque is @b aware of the discontiguous 782 * storage! 783 * 784 * The memory setup and layout occurs in the parent, _Base, and the iterator 785 * class is entirely responsible for @a leaping from one node to the next. 786 * All the implementation routines for deque itself work only through the 787 * start and finish iterators. This keeps the routines simple and sane, 788 * and we can use other standard algorithms as well. 789 */ 790 template<typename _Tp, typename _Alloc = std::allocator<_Tp> > 791 class deque : protected _Deque_base<_Tp, _Alloc> 792 { 793 #ifdef _GLIBCXX_CONCEPT_CHECKS 794 // concept requirements 795 typedef typename _Alloc::value_type _Alloc_value_type; 796 # if __cplusplus < 201103L 797 __glibcxx_class_requires(_Tp, _SGIAssignableConcept) 798 # endif 799 __glibcxx_class_requires2(_Tp, _Alloc_value_type, _SameTypeConcept) 800 #endif 801 802 #if __cplusplus >= 201103L 803 static_assert(is_same<typename remove_cv<_Tp>::type, _Tp>::value, 804 "std::deque must have a non-const, non-volatile value_type"); 805 # if __cplusplus > 201703L || defined __STRICT_ANSI__ 806 static_assert(is_same<typename _Alloc::value_type, _Tp>::value, 807 "std::deque must have the same value_type as its allocator"); 808 # endif 809 #endif 810 811 typedef _Deque_base<_Tp, _Alloc> _Base; 812 typedef typename _Base::_Tp_alloc_type _Tp_alloc_type; 813 typedef typename _Base::_Alloc_traits _Alloc_traits; 814 typedef typename _Base::_Map_pointer _Map_pointer; 815 816 public: 817 typedef _Tp value_type; 818 typedef typename _Alloc_traits::pointer pointer; 819 typedef typename _Alloc_traits::const_pointer const_pointer; 820 typedef typename _Alloc_traits::reference reference; 821 typedef typename _Alloc_traits::const_reference const_reference; 822 typedef typename _Base::iterator iterator; 823 typedef typename _Base::const_iterator const_iterator; 824 typedef std::reverse_iterator<const_iterator> const_reverse_iterator; 825 typedef std::reverse_iterator<iterator> reverse_iterator; 826 typedef size_t size_type; 827 typedef ptrdiff_t difference_type; 828 typedef _Alloc allocator_type; 829 830 private: 831 static size_t _S_buffer_size() _GLIBCXX_NOEXCEPT 832 { return __deque_buf_size(sizeof(_Tp)); } 833 834 // Functions controlling memory layout, and nothing else. 835 using _Base::_M_initialize_map; 836 using _Base::_M_create_nodes; 837 using _Base::_M_destroy_nodes; 838 using _Base::_M_allocate_node; 839 using _Base::_M_deallocate_node; 840 using _Base::_M_allocate_map; 841 using _Base::_M_deallocate_map; 842 using _Base::_M_get_Tp_allocator; 843 844 /** 845 * A total of four data members accumulated down the hierarchy. 846 * May be accessed via _M_impl.* 847 */ 848 using _Base::_M_impl; 849 850 public: 851 // [23.2.1.1] construct/copy/destroy 852 // (assign() and get_allocator() are also listed in this section) 853 854 /** 855 * @brief Creates a %deque with no elements. 856 */ 857 #if __cplusplus >= 201103L 858 deque() = default; 859 #else 860 deque() { } 861 #endif 862 863 /** 864 * @brief Creates a %deque with no elements. 865 * @param __a An allocator object. 866 */ 867 explicit 868 deque(const allocator_type& __a) 869 : _Base(__a, 0) { } 870 871 #if __cplusplus >= 201103L 872 /** 873 * @brief Creates a %deque with default constructed elements. 874 * @param __n The number of elements to initially create. 875 * @param __a An allocator. 876 * 877 * This constructor fills the %deque with @a n default 878 * constructed elements. 879 */ 880 explicit 881 deque(size_type __n, const allocator_type& __a = allocator_type()) 882 : _Base(__a, _S_check_init_len(__n, __a)) 883 { _M_default_initialize(); } 884 885 /** 886 * @brief Creates a %deque with copies of an exemplar element. 887 * @param __n The number of elements to initially create. 888 * @param __value An element to copy. 889 * @param __a An allocator. 890 * 891 * This constructor fills the %deque with @a __n copies of @a __value. 892 */ 893 deque(size_type __n, const value_type& __value, 894 const allocator_type& __a = allocator_type()) 895 : _Base(__a, _S_check_init_len(__n, __a)) 896 { _M_fill_initialize(__value); } 897 #else 898 /** 899 * @brief Creates a %deque with copies of an exemplar element. 900 * @param __n The number of elements to initially create. 901 * @param __value An element to copy. 902 * @param __a An allocator. 903 * 904 * This constructor fills the %deque with @a __n copies of @a __value. 905 */ 906 explicit 907 deque(size_type __n, const value_type& __value = value_type(), 908 const allocator_type& __a = allocator_type()) 909 : _Base(__a, _S_check_init_len(__n, __a)) 910 { _M_fill_initialize(__value); } 911 #endif 912 913 /** 914 * @brief %Deque copy constructor. 915 * @param __x A %deque of identical element and allocator types. 916 * 917 * The newly-created %deque uses a copy of the allocator object used 918 * by @a __x (unless the allocator traits dictate a different object). 919 */ 920 deque(const deque& __x) 921 : _Base(_Alloc_traits::_S_select_on_copy(__x._M_get_Tp_allocator()), 922 __x.size()) 923 { std::__uninitialized_copy_a(__x.begin(), __x.end(), 924 this->_M_impl._M_start, 925 _M_get_Tp_allocator()); } 926 927 #if __cplusplus >= 201103L 928 /** 929 * @brief %Deque move constructor. 930 * 931 * The newly-created %deque contains the exact contents of the 932 * moved instance. 933 * The contents of the moved instance are a valid, but unspecified 934 * %deque. 935 */ 936 deque(deque&&) = default; 937 938 /// Copy constructor with alternative allocator 939 deque(const deque& __x, const __type_identity_t<allocator_type>& __a) 940 : _Base(__a, __x.size()) 941 { std::__uninitialized_copy_a(__x.begin(), __x.end(), 942 this->_M_impl._M_start, 943 _M_get_Tp_allocator()); } 944 945 /// Move constructor with alternative allocator 946 deque(deque&& __x, const __type_identity_t<allocator_type>& __a) 947 : deque(std::move(__x), __a, typename _Alloc_traits::is_always_equal{}) 948 { } 949 950 private: 951 deque(deque&& __x, const allocator_type& __a, true_type) 952 : _Base(std::move(__x), __a) 953 { } 954 955 deque(deque&& __x, const allocator_type& __a, false_type) 956 : _Base(std::move(__x), __a, __x.size()) 957 { 958 if (__x.get_allocator() != __a && !__x.empty()) 959 { 960 std::__uninitialized_move_a(__x.begin(), __x.end(), 961 this->_M_impl._M_start, 962 _M_get_Tp_allocator()); 963 __x.clear(); 964 } 965 } 966 967 public: 968 /** 969 * @brief Builds a %deque from an initializer list. 970 * @param __l An initializer_list. 971 * @param __a An allocator object. 972 * 973 * Create a %deque consisting of copies of the elements in the 974 * initializer_list @a __l. 975 * 976 * This will call the element type's copy constructor N times 977 * (where N is __l.size()) and do no memory reallocation. 978 */ 979 deque(initializer_list<value_type> __l, 980 const allocator_type& __a = allocator_type()) 981 : _Base(__a) 982 { 983 _M_range_initialize(__l.begin(), __l.end(), 984 random_access_iterator_tag()); 985 } 986 #endif 987 988 /** 989 * @brief Builds a %deque from a range. 990 * @param __first An input iterator. 991 * @param __last An input iterator. 992 * @param __a An allocator object. 993 * 994 * Create a %deque consisting of copies of the elements from [__first, 995 * __last). 996 * 997 * If the iterators are forward, bidirectional, or random-access, then 998 * this will call the elements' copy constructor N times (where N is 999 * distance(__first,__last)) and do no memory reallocation. But if only 1000 * input iterators are used, then this will do at most 2N calls to the 1001 * copy constructor, and logN memory reallocations. 1002 */ 1003 #if __cplusplus >= 201103L 1004 template<typename _InputIterator, 1005 typename = std::_RequireInputIter<_InputIterator>> 1006 deque(_InputIterator __first, _InputIterator __last, 1007 const allocator_type& __a = allocator_type()) 1008 : _Base(__a) 1009 { 1010 _M_range_initialize(__first, __last, 1011 std::__iterator_category(__first)); 1012 } 1013 #else 1014 template<typename _InputIterator> 1015 deque(_InputIterator __first, _InputIterator __last, 1016 const allocator_type& __a = allocator_type()) 1017 : _Base(__a) 1018 { 1019 // Check whether it's an integral type. If so, it's not an iterator. 1020 typedef typename std::__is_integer<_InputIterator>::__type _Integral; 1021 _M_initialize_dispatch(__first, __last, _Integral()); 1022 } 1023 #endif 1024 1025 #if __glibcxx_containers_ranges // C++ >= 23 1026 /** 1027 * @brief Construct a deque from a range. 1028 * @param __rg A range of values that are convertible to `value_type`. 1029 * @since C++23 1030 */ 1031 template<__detail::__container_compatible_range<_Tp> _Rg> 1032 deque(from_range_t, _Rg&& __rg, const allocator_type& __a = _Alloc()) 1033 : deque(__a) 1034 { append_range(std::forward<_Rg>(__rg)); } 1035 #endif 1036 1037 /** 1038 * The dtor only erases the elements, and note that if the elements 1039 * themselves are pointers, the pointed-to memory is not touched in any 1040 * way. Managing the pointer is the user's responsibility. 1041 */ 1042 ~deque() 1043 { _M_destroy_data(begin(), end(), _M_get_Tp_allocator()); } 1044 1045 /** 1046 * @brief %Deque assignment operator. 1047 * @param __x A %deque of identical element and allocator types. 1048 * 1049 * All the elements of @a x are copied. 1050 * 1051 * The newly-created %deque uses a copy of the allocator object used 1052 * by @a __x (unless the allocator traits dictate a different object). 1053 */ 1054 deque& 1055 operator=(const deque& __x); 1056 1057 #if __cplusplus >= 201103L 1058 /** 1059 * @brief %Deque move assignment operator. 1060 * @param __x A %deque of identical element and allocator types. 1061 * 1062 * The contents of @a __x are moved into this deque (without copying, 1063 * if the allocators permit it). 1064 * @a __x is a valid, but unspecified %deque. 1065 */ 1066 deque& 1067 operator=(deque&& __x) noexcept(_Alloc_traits::_S_always_equal()) 1068 { 1069 using __always_equal = typename _Alloc_traits::is_always_equal; 1070 _M_move_assign1(std::move(__x), __always_equal{}); 1071 return *this; 1072 } 1073 1074 /** 1075 * @brief Assigns an initializer list to a %deque. 1076 * @param __l An initializer_list. 1077 * 1078 * This function fills a %deque with copies of the elements in the 1079 * initializer_list @a __l. 1080 * 1081 * Note that the assignment completely changes the %deque and that the 1082 * resulting %deque's size is the same as the number of elements 1083 * assigned. 1084 */ 1085 deque& 1086 operator=(initializer_list<value_type> __l) 1087 { 1088 _M_assign_aux(__l.begin(), __l.end(), 1089 random_access_iterator_tag()); 1090 return *this; 1091 } 1092 #endif 1093 1094 /** 1095 * @brief Assigns a given value to a %deque. 1096 * @param __n Number of elements to be assigned. 1097 * @param __val Value to be assigned. 1098 * 1099 * This function fills a %deque with @a n copies of the given 1100 * value. Note that the assignment completely changes the 1101 * %deque and that the resulting %deque's size is the same as 1102 * the number of elements assigned. 1103 */ 1104 void 1105 assign(size_type __n, const value_type& __val) 1106 { _M_fill_assign(__n, __val); } 1107 1108 /** 1109 * @brief Assigns a range to a %deque. 1110 * @param __first An input iterator. 1111 * @param __last An input iterator. 1112 * 1113 * This function fills a %deque with copies of the elements in the 1114 * range [__first,__last). 1115 * 1116 * Note that the assignment completely changes the %deque and that the 1117 * resulting %deque's size is the same as the number of elements 1118 * assigned. 1119 */ 1120 #if __cplusplus >= 201103L 1121 template<typename _InputIterator, 1122 typename = std::_RequireInputIter<_InputIterator>> 1123 void 1124 assign(_InputIterator __first, _InputIterator __last) 1125 { _M_assign_aux(__first, __last, std::__iterator_category(__first)); } 1126 #else 1127 template<typename _InputIterator> 1128 void 1129 assign(_InputIterator __first, _InputIterator __last) 1130 { 1131 typedef typename std::__is_integer<_InputIterator>::__type _Integral; 1132 _M_assign_dispatch(__first, __last, _Integral()); 1133 } 1134 #endif 1135 1136 #if __cplusplus >= 201103L 1137 /** 1138 * @brief Assigns an initializer list to a %deque. 1139 * @param __l An initializer_list. 1140 * 1141 * This function fills a %deque with copies of the elements in the 1142 * initializer_list @a __l. 1143 * 1144 * Note that the assignment completely changes the %deque and that the 1145 * resulting %deque's size is the same as the number of elements 1146 * assigned. 1147 */ 1148 void 1149 assign(initializer_list<value_type> __l) 1150 { _M_assign_aux(__l.begin(), __l.end(), random_access_iterator_tag()); } 1151 #endif 1152 1153 #if __glibcxx_containers_ranges // C++ >= 23 1154 /** 1155 * @brief Assign a range to the deque. 1156 * @param __rg A range of values that are convertible to `value_type`. 1157 * @pre `__rg` and `*this` do not overlap. 1158 * @since C++23 1159 */ 1160 template<__detail::__container_compatible_range<_Tp> _Rg> 1161 constexpr void 1162 assign_range(_Rg&& __rg) 1163 { 1164 static_assert(assignable_from<_Tp&, ranges::range_reference_t<_Rg>>); 1165 1166 if constexpr (ranges::forward_range<_Rg> || ranges::sized_range<_Rg>) 1167 { 1168 const size_type __n(ranges::distance(__rg)); 1169 if (__n <= size()) 1170 { 1171 auto __res = ranges::copy(__rg, begin()); 1172 return _M_erase_at_end(__res.out); 1173 } 1174 1175 auto __rest = ranges::copy_n(ranges::begin(__rg), size(), 1176 begin()).in; 1177 _M_range_append(std::move(__rest), ranges::end(__rg), 1178 __n - size()); 1179 } 1180 else 1181 { 1182 auto __first = ranges::begin(__rg); 1183 const auto __last = ranges::end(__rg); 1184 for (iterator __it = begin(), __end = end(); 1185 __it != __end; (void)++__first, ++__it) 1186 { 1187 if (__first == __last) 1188 return _M_erase_at_end(__it); 1189 1190 *__it = *__first; 1191 } 1192 1193 for (; __first != __last; ++__first) 1194 emplace_back(*__first); 1195 } 1196 } 1197 #endif // containers_ranges 1198 1199 1200 /// Get a copy of the memory allocation object. 1201 _GLIBCXX_NODISCARD 1202 allocator_type 1203 get_allocator() const _GLIBCXX_NOEXCEPT 1204 { return _Base::get_allocator(); } 1205 1206 // iterators 1207 /** 1208 * Returns a read/write iterator that points to the first element in the 1209 * %deque. Iteration is done in ordinary element order. 1210 */ 1211 _GLIBCXX_NODISCARD 1212 iterator 1213 begin() _GLIBCXX_NOEXCEPT 1214 { return this->_M_impl._M_start; } 1215 1216 /** 1217 * Returns a read-only (constant) iterator that points to the first 1218 * element in the %deque. Iteration is done in ordinary element order. 1219 */ 1220 _GLIBCXX_NODISCARD 1221 const_iterator 1222 begin() const _GLIBCXX_NOEXCEPT 1223 { return this->_M_impl._M_start; } 1224 1225 /** 1226 * Returns a read/write iterator that points one past the last 1227 * element in the %deque. Iteration is done in ordinary 1228 * element order. 1229 */ 1230 _GLIBCXX_NODISCARD 1231 iterator 1232 end() _GLIBCXX_NOEXCEPT 1233 { return this->_M_impl._M_finish; } 1234 1235 /** 1236 * Returns a read-only (constant) iterator that points one past 1237 * the last element in the %deque. Iteration is done in 1238 * ordinary element order. 1239 */ 1240 _GLIBCXX_NODISCARD 1241 const_iterator 1242 end() const _GLIBCXX_NOEXCEPT 1243 { return this->_M_impl._M_finish; } 1244 1245 /** 1246 * Returns a read/write reverse iterator that points to the 1247 * last element in the %deque. Iteration is done in reverse 1248 * element order. 1249 */ 1250 _GLIBCXX_NODISCARD 1251 reverse_iterator 1252 rbegin() _GLIBCXX_NOEXCEPT 1253 { return reverse_iterator(this->_M_impl._M_finish); } 1254 1255 /** 1256 * Returns a read-only (constant) reverse iterator that points 1257 * to the last element in the %deque. Iteration is done in 1258 * reverse element order. 1259 */ 1260 _GLIBCXX_NODISCARD 1261 const_reverse_iterator 1262 rbegin() const _GLIBCXX_NOEXCEPT 1263 { return const_reverse_iterator(this->_M_impl._M_finish); } 1264 1265 /** 1266 * Returns a read/write reverse iterator that points to one 1267 * before the first element in the %deque. Iteration is done 1268 * in reverse element order. 1269 */ 1270 _GLIBCXX_NODISCARD 1271 reverse_iterator 1272 rend() _GLIBCXX_NOEXCEPT 1273 { return reverse_iterator(this->_M_impl._M_start); } 1274 1275 /** 1276 * Returns a read-only (constant) reverse iterator that points 1277 * to one before the first element in the %deque. Iteration is 1278 * done in reverse element order. 1279 */ 1280 _GLIBCXX_NODISCARD 1281 const_reverse_iterator 1282 rend() const _GLIBCXX_NOEXCEPT 1283 { return const_reverse_iterator(this->_M_impl._M_start); } 1284 1285 #if __cplusplus >= 201103L 1286 /** 1287 * Returns a read-only (constant) iterator that points to the first 1288 * element in the %deque. Iteration is done in ordinary element order. 1289 */ 1290 [[__nodiscard__]] 1291 const_iterator 1292 cbegin() const noexcept 1293 { return this->_M_impl._M_start; } 1294 1295 /** 1296 * Returns a read-only (constant) iterator that points one past 1297 * the last element in the %deque. Iteration is done in 1298 * ordinary element order. 1299 */ 1300 [[__nodiscard__]] 1301 const_iterator 1302 cend() const noexcept 1303 { return this->_M_impl._M_finish; } 1304 1305 /** 1306 * Returns a read-only (constant) reverse iterator that points 1307 * to the last element in the %deque. Iteration is done in 1308 * reverse element order. 1309 */ 1310 [[__nodiscard__]] 1311 const_reverse_iterator 1312 crbegin() const noexcept 1313 { return const_reverse_iterator(this->_M_impl._M_finish); } 1314 1315 /** 1316 * Returns a read-only (constant) reverse iterator that points 1317 * to one before the first element in the %deque. Iteration is 1318 * done in reverse element order. 1319 */ 1320 [[__nodiscard__]] 1321 const_reverse_iterator 1322 crend() const noexcept 1323 { return const_reverse_iterator(this->_M_impl._M_start); } 1324 #endif 1325 1326 // [23.2.1.2] capacity 1327 /** Returns the number of elements in the %deque. */ 1328 _GLIBCXX_NODISCARD 1329 size_type 1330 size() const _GLIBCXX_NOEXCEPT 1331 { 1332 size_type __sz = this->_M_impl._M_finish - this->_M_impl._M_start; 1333 if (__sz > max_size ()) 1334 __builtin_unreachable (); 1335 return __sz; 1336 } 1337 1338 /** Returns the size() of the largest possible %deque. */ 1339 _GLIBCXX_NODISCARD 1340 size_type 1341 max_size() const _GLIBCXX_NOEXCEPT 1342 { return _S_max_size(_M_get_Tp_allocator()); } 1343 1344 #if __cplusplus >= 201103L 1345 /** 1346 * @brief Resizes the %deque to the specified number of elements. 1347 * @param __new_size Number of elements the %deque should contain. 1348 * 1349 * This function will %resize the %deque to the specified 1350 * number of elements. If the number is smaller than the 1351 * %deque's current size the %deque is truncated, otherwise 1352 * default constructed elements are appended. 1353 */ 1354 void 1355 resize(size_type __new_size) 1356 { 1357 const size_type __len = size(); 1358 if (__new_size > __len) 1359 _M_default_append(__new_size - __len); 1360 else if (__new_size < __len) 1361 _M_erase_at_end(this->_M_impl._M_start 1362 + difference_type(__new_size)); 1363 } 1364 1365 /** 1366 * @brief Resizes the %deque to the specified number of elements. 1367 * @param __new_size Number of elements the %deque should contain. 1368 * @param __x Data with which new elements should be populated. 1369 * 1370 * This function will %resize the %deque to the specified 1371 * number of elements. If the number is smaller than the 1372 * %deque's current size the %deque is truncated, otherwise the 1373 * %deque is extended and new elements are populated with given 1374 * data. 1375 */ 1376 void 1377 resize(size_type __new_size, const value_type& __x) 1378 #else 1379 /** 1380 * @brief Resizes the %deque to the specified number of elements. 1381 * @param __new_size Number of elements the %deque should contain. 1382 * @param __x Data with which new elements should be populated. 1383 * 1384 * This function will %resize the %deque to the specified 1385 * number of elements. If the number is smaller than the 1386 * %deque's current size the %deque is truncated, otherwise the 1387 * %deque is extended and new elements are populated with given 1388 * data. 1389 */ 1390 void 1391 resize(size_type __new_size, value_type __x = value_type()) 1392 #endif 1393 { 1394 const size_type __len = size(); 1395 if (__new_size > __len) 1396 _M_fill_insert(this->_M_impl._M_finish, __new_size - __len, __x); 1397 else if (__new_size < __len) 1398 _M_erase_at_end(this->_M_impl._M_start 1399 + difference_type(__new_size)); 1400 } 1401 1402 #if __cplusplus >= 201103L 1403 /** A non-binding request to reduce memory use. */ 1404 void 1405 shrink_to_fit() noexcept 1406 { _M_shrink_to_fit(); } 1407 #endif 1408 1409 /** 1410 * Returns true if the %deque is empty. (Thus begin() would 1411 * equal end().) 1412 */ 1413 _GLIBCXX_NODISCARD bool 1414 empty() const _GLIBCXX_NOEXCEPT 1415 { return this->_M_impl._M_finish == this->_M_impl._M_start; } 1416 1417 // element access 1418 /** 1419 * @brief Subscript access to the data contained in the %deque. 1420 * @param __n The index of the element for which data should be 1421 * accessed. 1422 * @return Read/write reference to data. 1423 * 1424 * This operator allows for easy, array-style, data access. 1425 * Note that data access with this operator is unchecked and 1426 * out_of_range lookups are not defined. (For checked lookups 1427 * see at().) 1428 */ 1429 _GLIBCXX_NODISCARD 1430 reference 1431 operator[](size_type __n) _GLIBCXX_NOEXCEPT 1432 { 1433 __glibcxx_requires_subscript(__n); 1434 return this->_M_impl._M_start[difference_type(__n)]; 1435 } 1436 1437 /** 1438 * @brief Subscript access to the data contained in the %deque. 1439 * @param __n The index of the element for which data should be 1440 * accessed. 1441 * @return Read-only (constant) reference to data. 1442 * 1443 * This operator allows for easy, array-style, data access. 1444 * Note that data access with this operator is unchecked and 1445 * out_of_range lookups are not defined. (For checked lookups 1446 * see at().) 1447 */ 1448 _GLIBCXX_NODISCARD 1449 const_reference 1450 operator[](size_type __n) const _GLIBCXX_NOEXCEPT 1451 { 1452 __glibcxx_requires_subscript(__n); 1453 return this->_M_impl._M_start[difference_type(__n)]; 1454 } 1455 1456 protected: 1457 /// Safety check used only from at(). 1458 void 1459 _M_range_check(size_type __n) const 1460 { 1461 if (__n >= this->size()) 1462 __throw_out_of_range_fmt(__N("deque::_M_range_check: __n " 1463 "(which is %zu)>= this->size() " 1464 "(which is %zu)"), 1465 __n, this->size()); 1466 } 1467 1468 public: 1469 /** 1470 * @brief Provides access to the data contained in the %deque. 1471 * @param __n The index of the element for which data should be 1472 * accessed. 1473 * @return Read/write reference to data. 1474 * @throw std::out_of_range If @a __n is an invalid index. 1475 * 1476 * This function provides for safer data access. The parameter 1477 * is first checked that it is in the range of the deque. The 1478 * function throws out_of_range if the check fails. 1479 */ 1480 reference 1481 at(size_type __n) 1482 { 1483 _M_range_check(__n); 1484 return (*this)[__n]; 1485 } 1486 1487 /** 1488 * @brief Provides access to the data contained in the %deque. 1489 * @param __n The index of the element for which data should be 1490 * accessed. 1491 * @return Read-only (constant) reference to data. 1492 * @throw std::out_of_range If @a __n is an invalid index. 1493 * 1494 * This function provides for safer data access. The parameter is first 1495 * checked that it is in the range of the deque. The function throws 1496 * out_of_range if the check fails. 1497 */ 1498 const_reference 1499 at(size_type __n) const 1500 { 1501 _M_range_check(__n); 1502 return (*this)[__n]; 1503 } 1504 1505 /** 1506 * Returns a read/write reference to the data at the first 1507 * element of the %deque. 1508 */ 1509 _GLIBCXX_NODISCARD 1510 reference 1511 front() _GLIBCXX_NOEXCEPT 1512 { 1513 __glibcxx_requires_nonempty(); 1514 return *begin(); 1515 } 1516 1517 /** 1518 * Returns a read-only (constant) reference to the data at the first 1519 * element of the %deque. 1520 */ 1521 _GLIBCXX_NODISCARD 1522 const_reference 1523 front() const _GLIBCXX_NOEXCEPT 1524 { 1525 __glibcxx_requires_nonempty(); 1526 return *begin(); 1527 } 1528 1529 /** 1530 * Returns a read/write reference to the data at the last element of the 1531 * %deque. 1532 */ 1533 _GLIBCXX_NODISCARD 1534 reference 1535 back() _GLIBCXX_NOEXCEPT 1536 { 1537 __glibcxx_requires_nonempty(); 1538 iterator __tmp = end(); 1539 --__tmp; 1540 return *__tmp; 1541 } 1542 1543 /** 1544 * Returns a read-only (constant) reference to the data at the last 1545 * element of the %deque. 1546 */ 1547 _GLIBCXX_NODISCARD 1548 const_reference 1549 back() const _GLIBCXX_NOEXCEPT 1550 { 1551 __glibcxx_requires_nonempty(); 1552 const_iterator __tmp = end(); 1553 --__tmp; 1554 return *__tmp; 1555 } 1556 1557 // [23.2.1.2] modifiers 1558 /** 1559 * @brief Add data to the front of the %deque. 1560 * @param __x Data to be added. 1561 * 1562 * This is a typical stack operation. The function creates an 1563 * element at the front of the %deque and assigns the given 1564 * data to it. Due to the nature of a %deque this operation 1565 * can be done in constant time. 1566 */ 1567 void 1568 push_front(const value_type& __x) 1569 { 1570 if (this->_M_impl._M_start._M_cur != this->_M_impl._M_start._M_first) 1571 { 1572 _Alloc_traits::construct(this->_M_impl, 1573 this->_M_impl._M_start._M_cur - 1, 1574 __x); 1575 --this->_M_impl._M_start._M_cur; 1576 } 1577 else 1578 _M_push_front_aux(__x); 1579 } 1580 1581 #if __cplusplus >= 201103L 1582 void 1583 push_front(value_type&& __x) 1584 { emplace_front(std::move(__x)); } 1585 1586 template<typename... _Args> 1587 #if __cplusplus > 201402L 1588 reference 1589 #else 1590 void 1591 #endif 1592 emplace_front(_Args&&... __args); 1593 #endif 1594 1595 /** 1596 * @brief Add data to the end of the %deque. 1597 * @param __x Data to be added. 1598 * 1599 * This is a typical stack operation. The function creates an 1600 * element at the end of the %deque and assigns the given data 1601 * to it. Due to the nature of a %deque this operation can be 1602 * done in constant time. 1603 */ 1604 void 1605 push_back(const value_type& __x) 1606 { 1607 if (this->_M_impl._M_finish._M_cur 1608 != this->_M_impl._M_finish._M_last - 1) 1609 { 1610 _Alloc_traits::construct(this->_M_impl, 1611 this->_M_impl._M_finish._M_cur, __x); 1612 ++this->_M_impl._M_finish._M_cur; 1613 } 1614 else 1615 _M_push_back_aux(__x); 1616 } 1617 1618 #if __cplusplus >= 201103L 1619 void 1620 push_back(value_type&& __x) 1621 { emplace_back(std::move(__x)); } 1622 1623 template<typename... _Args> 1624 #if __cplusplus > 201402L 1625 reference 1626 #else 1627 void 1628 #endif 1629 emplace_back(_Args&&... __args); 1630 #endif 1631 1632 /** 1633 * @brief Removes first element. 1634 * 1635 * This is a typical stack operation. It shrinks the %deque by one. 1636 * 1637 * Note that no data is returned, and if the first element's data is 1638 * needed, it should be retrieved before pop_front() is called. 1639 */ 1640 void 1641 pop_front() _GLIBCXX_NOEXCEPT 1642 { 1643 __glibcxx_requires_nonempty(); 1644 if (this->_M_impl._M_start._M_cur 1645 != this->_M_impl._M_start._M_last - 1) 1646 { 1647 _Alloc_traits::destroy(_M_get_Tp_allocator(), 1648 this->_M_impl._M_start._M_cur); 1649 ++this->_M_impl._M_start._M_cur; 1650 } 1651 else 1652 _M_pop_front_aux(); 1653 } 1654 1655 /** 1656 * @brief Removes last element. 1657 * 1658 * This is a typical stack operation. It shrinks the %deque by one. 1659 * 1660 * Note that no data is returned, and if the last element's data is 1661 * needed, it should be retrieved before pop_back() is called. 1662 */ 1663 void 1664 pop_back() _GLIBCXX_NOEXCEPT 1665 { 1666 __glibcxx_requires_nonempty(); 1667 if (this->_M_impl._M_finish._M_cur 1668 != this->_M_impl._M_finish._M_first) 1669 { 1670 --this->_M_impl._M_finish._M_cur; 1671 _Alloc_traits::destroy(_M_get_Tp_allocator(), 1672 this->_M_impl._M_finish._M_cur); 1673 } 1674 else 1675 _M_pop_back_aux(); 1676 } 1677 1678 #if __cplusplus >= 201103L 1679 /** 1680 * @brief Inserts an object in %deque before specified iterator. 1681 * @param __position A const_iterator into the %deque. 1682 * @param __args Arguments. 1683 * @return An iterator that points to the inserted data. 1684 * 1685 * This function will insert an object of type T constructed 1686 * with T(std::forward<Args>(args)...) before the specified location. 1687 */ 1688 template<typename... _Args> 1689 iterator 1690 emplace(const_iterator __position, _Args&&... __args); 1691 1692 /** 1693 * @brief Inserts given value into %deque before specified iterator. 1694 * @param __position A const_iterator into the %deque. 1695 * @param __x Data to be inserted. 1696 * @return An iterator that points to the inserted data. 1697 * 1698 * This function will insert a copy of the given value before the 1699 * specified location. 1700 */ 1701 iterator 1702 insert(const_iterator __position, const value_type& __x); 1703 #else 1704 /** 1705 * @brief Inserts given value into %deque before specified iterator. 1706 * @param __position An iterator into the %deque. 1707 * @param __x Data to be inserted. 1708 * @return An iterator that points to the inserted data. 1709 * 1710 * This function will insert a copy of the given value before the 1711 * specified location. 1712 */ 1713 iterator 1714 insert(iterator __position, const value_type& __x); 1715 #endif 1716 1717 #if __cplusplus >= 201103L 1718 /** 1719 * @brief Inserts given rvalue into %deque before specified iterator. 1720 * @param __position A const_iterator into the %deque. 1721 * @param __x Data to be inserted. 1722 * @return An iterator that points to the inserted data. 1723 * 1724 * This function will insert a copy of the given rvalue before the 1725 * specified location. 1726 */ 1727 iterator 1728 insert(const_iterator __position, value_type&& __x) 1729 { return emplace(__position, std::move(__x)); } 1730 1731 /** 1732 * @brief Inserts an initializer list into the %deque. 1733 * @param __p An iterator into the %deque. 1734 * @param __l An initializer_list. 1735 * @return An iterator that points to the inserted data. 1736 * 1737 * This function will insert copies of the data in the 1738 * initializer_list @a __l into the %deque before the location 1739 * specified by @a __p. This is known as <em>list insert</em>. 1740 */ 1741 iterator 1742 insert(const_iterator __p, initializer_list<value_type> __l) 1743 { 1744 auto __offset = __p - cbegin(); 1745 _M_range_insert_aux(__p._M_const_cast(), __l.begin(), __l.end(), 1746 std::random_access_iterator_tag()); 1747 return begin() + __offset; 1748 } 1749 1750 /** 1751 * @brief Inserts a number of copies of given data into the %deque. 1752 * @param __position A const_iterator into the %deque. 1753 * @param __n Number of elements to be inserted. 1754 * @param __x Data to be inserted. 1755 * @return An iterator that points to the inserted data. 1756 * 1757 * This function will insert a specified number of copies of the given 1758 * data before the location specified by @a __position. 1759 */ 1760 iterator 1761 insert(const_iterator __position, size_type __n, const value_type& __x) 1762 { 1763 difference_type __offset = __position - cbegin(); 1764 _M_fill_insert(__position._M_const_cast(), __n, __x); 1765 return begin() + __offset; 1766 } 1767 #else 1768 /** 1769 * @brief Inserts a number of copies of given data into the %deque. 1770 * @param __position An iterator into the %deque. 1771 * @param __n Number of elements to be inserted. 1772 * @param __x Data to be inserted. 1773 * 1774 * This function will insert a specified number of copies of the given 1775 * data before the location specified by @a __position. 1776 */ 1777 void 1778 insert(iterator __position, size_type __n, const value_type& __x) 1779 { _M_fill_insert(__position, __n, __x); } 1780 #endif 1781 1782 #if __cplusplus >= 201103L 1783 /** 1784 * @brief Inserts a range into the %deque. 1785 * @param __position A const_iterator into the %deque. 1786 * @param __first An input iterator. 1787 * @param __last An input iterator. 1788 * @return An iterator that points to the inserted data. 1789 * 1790 * This function will insert copies of the data in the range 1791 * [__first,__last) into the %deque before the location specified 1792 * by @a __position. This is known as <em>range insert</em>. 1793 */ 1794 template<typename _InputIterator, 1795 typename = std::_RequireInputIter<_InputIterator>> 1796 iterator 1797 insert(const_iterator __position, _InputIterator __first, 1798 _InputIterator __last) 1799 { 1800 difference_type __offset = __position - cbegin(); 1801 _M_range_insert_aux(__position._M_const_cast(), __first, __last, 1802 std::__iterator_category(__first)); 1803 return begin() + __offset; 1804 } 1805 #else 1806 /** 1807 * @brief Inserts a range into the %deque. 1808 * @param __position An iterator into the %deque. 1809 * @param __first An input iterator. 1810 * @param __last An input iterator. 1811 * 1812 * This function will insert copies of the data in the range 1813 * [__first,__last) into the %deque before the location specified 1814 * by @a __position. This is known as <em>range insert</em>. 1815 */ 1816 template<typename _InputIterator> 1817 void 1818 insert(iterator __position, _InputIterator __first, 1819 _InputIterator __last) 1820 { 1821 // Check whether it's an integral type. If so, it's not an iterator. 1822 typedef typename std::__is_integer<_InputIterator>::__type _Integral; 1823 _M_insert_dispatch(__position, __first, __last, _Integral()); 1824 } 1825 #endif 1826 1827 #if __glibcxx_containers_ranges // C++ >= 23 1828 /** 1829 * @brief Insert a range into the deque. 1830 * @param __rg A range of values that are convertible to `value_type`. 1831 * @pre `__rg` and `*this` do not overlap. 1832 * @return An iterator that points to the first new element inserted, 1833 * or to `__pos` if `__rg` is an empty range. 1834 * @since C++23 1835 */ 1836 template<__detail::__container_compatible_range<_Tp> _Rg> 1837 iterator 1838 insert_range(const_iterator __pos, _Rg&& __rg); 1839 1840 /** 1841 * @brief Prepend a range at the begining of the deque. 1842 * @param __rg A range of values that are convertible to `value_type`. 1843 * @since C++23 1844 */ 1845 template<__detail::__container_compatible_range<_Tp> _Rg> 1846 void 1847 prepend_range(_Rg&& __rg); 1848 1849 /** 1850 * @brief Append a range at the end of the deque. 1851 * @param __rg A range of values that are convertible to `value_type`. 1852 * @since C++23 1853 */ 1854 template<__detail::__container_compatible_range<_Tp> _Rg> 1855 void 1856 append_range(_Rg&& __rg); 1857 #endif // containers_ranges 1858 1859 /** 1860 * @brief Remove element at given position. 1861 * @param __position Iterator pointing to element to be erased. 1862 * @return An iterator pointing to the next element (or end()). 1863 * 1864 * This function will erase the element at the given position and thus 1865 * shorten the %deque by one. 1866 * 1867 * The user is cautioned that 1868 * this function only erases the element, and that if the element is 1869 * itself a pointer, the pointed-to memory is not touched in any way. 1870 * Managing the pointer is the user's responsibility. 1871 */ 1872 iterator 1873 #if __cplusplus >= 201103L 1874 erase(const_iterator __position) 1875 #else 1876 erase(iterator __position) 1877 #endif 1878 { return _M_erase(__position._M_const_cast()); } 1879 1880 /** 1881 * @brief Remove a range of elements. 1882 * @param __first Iterator pointing to the first element to be erased. 1883 * @param __last Iterator pointing to one past the last element to be 1884 * erased. 1885 * @return An iterator pointing to the element pointed to by @a last 1886 * prior to erasing (or end()). 1887 * 1888 * This function will erase the elements in the range 1889 * [__first,__last) and shorten the %deque accordingly. 1890 * 1891 * The user is cautioned that 1892 * this function only erases the elements, and that if the elements 1893 * themselves are pointers, the pointed-to memory is not touched in any 1894 * way. Managing the pointer is the user's responsibility. 1895 */ 1896 iterator 1897 #if __cplusplus >= 201103L 1898 erase(const_iterator __first, const_iterator __last) 1899 #else 1900 erase(iterator __first, iterator __last) 1901 #endif 1902 { return _M_erase(__first._M_const_cast(), __last._M_const_cast()); } 1903 1904 /** 1905 * @brief Swaps data with another %deque. 1906 * @param __x A %deque of the same element and allocator types. 1907 * 1908 * This exchanges the elements between two deques in constant time. 1909 * (Four pointers, so it should be quite fast.) 1910 * Note that the global std::swap() function is specialized such that 1911 * std::swap(d1,d2) will feed to this function. 1912 * 1913 * Whether the allocators are swapped depends on the allocator traits. 1914 */ 1915 void 1916 swap(deque& __x) _GLIBCXX_NOEXCEPT 1917 { 1918 #if __cplusplus >= 201103L 1919 __glibcxx_assert(_Alloc_traits::propagate_on_container_swap::value 1920 || _M_get_Tp_allocator() == __x._M_get_Tp_allocator()); 1921 #endif 1922 _M_impl._M_swap_data(__x._M_impl); 1923 _Alloc_traits::_S_on_swap(_M_get_Tp_allocator(), 1924 __x._M_get_Tp_allocator()); 1925 } 1926 1927 /** 1928 * Erases all the elements. Note that this function only erases the 1929 * elements, and that if the elements themselves are pointers, the 1930 * pointed-to memory is not touched in any way. Managing the pointer is 1931 * the user's responsibility. 1932 */ 1933 void 1934 clear() _GLIBCXX_NOEXCEPT 1935 { _M_erase_at_end(begin()); } 1936 1937 protected: 1938 // Internal constructor functions follow. 1939 1940 #if __cplusplus < 201103L 1941 // called by the range constructor to implement [23.1.1]/9 1942 1943 // _GLIBCXX_RESOLVE_LIB_DEFECTS 1944 // 438. Ambiguity in the "do the right thing" clause 1945 template<typename _Integer> 1946 void 1947 _M_initialize_dispatch(_Integer __n, _Integer __x, __true_type) 1948 { 1949 _M_initialize_map(_S_check_init_len(static_cast<size_type>(__n), 1950 _M_get_Tp_allocator())); 1951 _M_fill_initialize(__x); 1952 } 1953 1954 // called by the range constructor to implement [23.1.1]/9 1955 template<typename _InputIterator> 1956 void 1957 _M_initialize_dispatch(_InputIterator __first, _InputIterator __last, 1958 __false_type) 1959 { 1960 _M_range_initialize(__first, __last, 1961 std::__iterator_category(__first)); 1962 } 1963 #endif 1964 1965 static size_t 1966 _S_check_init_len(size_t __n, const allocator_type& __a) 1967 { 1968 if (__n > _S_max_size(__a)) 1969 __throw_length_error( 1970 __N("cannot create std::deque larger than max_size()")); 1971 return __n; 1972 } 1973 1974 static size_type 1975 _S_max_size(const _Tp_alloc_type& __a) _GLIBCXX_NOEXCEPT 1976 { 1977 const size_t __diffmax = __gnu_cxx::__numeric_traits<ptrdiff_t>::__max; 1978 const size_t __allocmax = _Alloc_traits::max_size(__a); 1979 return (std::min)(__diffmax, __allocmax); 1980 } 1981 1982 // called by the second initialize_dispatch above 1983 ///@{ 1984 /** 1985 * @brief Fills the deque with whatever is in [first,last). 1986 * @param __first An input iterator. 1987 * @param __last An input iterator. 1988 * @return Nothing. 1989 * 1990 * If the iterators are actually forward iterators (or better), then the 1991 * memory layout can be done all at once. Else we move forward using 1992 * push_back on each value from the iterator. 1993 */ 1994 template<typename _InputIterator> 1995 void 1996 _M_range_initialize(_InputIterator __first, _InputIterator __last, 1997 std::input_iterator_tag); 1998 1999 // called by the second initialize_dispatch above 2000 template<typename _ForwardIterator> 2001 void 2002 _M_range_initialize(_ForwardIterator __first, _ForwardIterator __last, 2003 std::forward_iterator_tag); 2004 ///@} 2005 2006 /** 2007 * @brief Fills the %deque with copies of value. 2008 * @param __value Initial value. 2009 * @return Nothing. 2010 * @pre _M_start and _M_finish have already been initialized, 2011 * but none of the %deque's elements have yet been constructed. 2012 * 2013 * This function is called only when the user provides an explicit size 2014 * (with or without an explicit exemplar value). 2015 */ 2016 void 2017 _M_fill_initialize(const value_type& __value); 2018 2019 #if __cplusplus >= 201103L 2020 // called by deque(n). 2021 void 2022 _M_default_initialize(); 2023 #endif 2024 2025 // Internal assign functions follow. The *_aux functions do the actual 2026 // assignment work for the range versions. 2027 2028 #if __cplusplus < 201103L 2029 // called by the range assign to implement [23.1.1]/9 2030 2031 // _GLIBCXX_RESOLVE_LIB_DEFECTS 2032 // 438. Ambiguity in the "do the right thing" clause 2033 template<typename _Integer> 2034 void 2035 _M_assign_dispatch(_Integer __n, _Integer __val, __true_type) 2036 { _M_fill_assign(__n, __val); } 2037 2038 // called by the range assign to implement [23.1.1]/9 2039 template<typename _InputIterator> 2040 void 2041 _M_assign_dispatch(_InputIterator __first, _InputIterator __last, 2042 __false_type) 2043 { _M_assign_aux(__first, __last, std::__iterator_category(__first)); } 2044 #endif 2045 2046 // called by the second assign_dispatch above 2047 template<typename _InputIterator> 2048 void 2049 _M_assign_aux(_InputIterator __first, _InputIterator __last, 2050 std::input_iterator_tag); 2051 2052 // called by the second assign_dispatch above 2053 template<typename _ForwardIterator> 2054 void 2055 _M_assign_aux(_ForwardIterator __first, _ForwardIterator __last, 2056 std::forward_iterator_tag) 2057 { 2058 const size_type __len = std::distance(__first, __last); 2059 if (__len > size()) 2060 { 2061 _ForwardIterator __mid = __first; 2062 std::advance(__mid, size()); 2063 std::copy(__first, __mid, begin()); 2064 _M_range_insert_aux(end(), __mid, __last, 2065 std::__iterator_category(__first)); 2066 } 2067 else 2068 _M_erase_at_end(std::copy(__first, __last, begin())); 2069 } 2070 2071 // Called by assign(n,t), and the range assign when it turns out 2072 // to be the same thing. 2073 void 2074 _M_fill_assign(size_type __n, const value_type& __val) 2075 { 2076 if (__n > size()) 2077 { 2078 std::fill(begin(), end(), __val); 2079 _M_fill_insert(end(), __n - size(), __val); 2080 } 2081 else 2082 { 2083 _M_erase_at_end(begin() + difference_type(__n)); 2084 std::fill(begin(), end(), __val); 2085 } 2086 } 2087 2088 ///@{ 2089 /// Helper functions for push_* and pop_*. 2090 #if __cplusplus < 201103L 2091 void _M_push_back_aux(const value_type&); 2092 2093 void _M_push_front_aux(const value_type&); 2094 #else 2095 template<typename... _Args> 2096 void _M_push_back_aux(_Args&&... __args); 2097 2098 template<typename... _Args> 2099 void _M_push_front_aux(_Args&&... __args); 2100 #endif 2101 2102 void _M_pop_back_aux(); 2103 2104 void _M_pop_front_aux(); 2105 ///@} 2106 2107 // Internal insert functions follow. The *_aux functions do the actual 2108 // insertion work when all shortcuts fail. 2109 2110 #if __cplusplus < 201103L 2111 // called by the range insert to implement [23.1.1]/9 2112 2113 // _GLIBCXX_RESOLVE_LIB_DEFECTS 2114 // 438. Ambiguity in the "do the right thing" clause 2115 template<typename _Integer> 2116 void 2117 _M_insert_dispatch(iterator __pos, 2118 _Integer __n, _Integer __x, __true_type) 2119 { _M_fill_insert(__pos, __n, __x); } 2120 2121 // called by the range insert to implement [23.1.1]/9 2122 template<typename _InputIterator> 2123 void 2124 _M_insert_dispatch(iterator __pos, 2125 _InputIterator __first, _InputIterator __last, 2126 __false_type) 2127 { 2128 _M_range_insert_aux(__pos, __first, __last, 2129 std::__iterator_category(__first)); 2130 } 2131 #endif 2132 2133 // insert [__first, __last) at the front, assumes distance(__first, __last) is n 2134 template<typename _InputIterator, typename _Sentinel> 2135 void _M_range_prepend(_InputIterator __first, _Sentinel __last, 2136 size_type __n); 2137 2138 // insert [__first, __last) at the back, assumes distance(__first, __last) is n 2139 template<typename _InputIterator, typename _Sentinel> 2140 void _M_range_append(_InputIterator __first, _Sentinel __last, 2141 size_type __n); 2142 2143 // called by the second insert_dispatch above 2144 template<typename _InputIterator> 2145 void 2146 _M_range_insert_aux(iterator __pos, _InputIterator __first, 2147 _InputIterator __last, std::input_iterator_tag); 2148 2149 // called by the second insert_dispatch above 2150 template<typename _ForwardIterator> 2151 void 2152 _M_range_insert_aux(iterator __pos, _ForwardIterator __first, 2153 _ForwardIterator __last, std::forward_iterator_tag); 2154 2155 // Called by insert(p,n,x), and the range insert when it turns out to be 2156 // the same thing. Can use fill functions in optimal situations, 2157 // otherwise passes off to insert_aux(p,n,x). 2158 void 2159 _M_fill_insert(iterator __pos, size_type __n, const value_type& __x); 2160 2161 // called by insert(p,x) 2162 #if __cplusplus < 201103L 2163 iterator 2164 _M_insert_aux(iterator __pos, const value_type& __x); 2165 #else 2166 iterator 2167 _M_insert_aux(iterator __pos, const value_type& __x) 2168 { return _M_emplace_aux(__pos, __x); } 2169 2170 template<typename... _Args> 2171 iterator 2172 _M_emplace_aux(iterator __pos, _Args&&... __args); 2173 #endif 2174 2175 // called by insert(p,n,x) via fill_insert 2176 void 2177 _M_insert_aux(iterator __pos, size_type __n, const value_type& __x); 2178 2179 // called by range_insert_aux for forward iterators 2180 template<typename _ForwardIterator> 2181 void 2182 _M_insert_aux(iterator __pos, 2183 _ForwardIterator __first, _ForwardIterator __last, 2184 size_type __n); 2185 2186 2187 // Internal erase functions follow. 2188 2189 void 2190 _M_destroy_data_aux(iterator __first, iterator __last); 2191 2192 // Called by ~deque(). 2193 // NB: Doesn't deallocate the nodes. 2194 template<typename _Alloc1> 2195 void 2196 _M_destroy_data(iterator __first, iterator __last, const _Alloc1&) 2197 { _M_destroy_data_aux(__first, __last); } 2198 2199 void 2200 _M_destroy_data(iterator __first, iterator __last, 2201 const std::allocator<_Tp>&) 2202 { 2203 if (!__has_trivial_destructor(value_type)) 2204 _M_destroy_data_aux(__first, __last); 2205 } 2206 2207 // Called by erase(q1, q2). 2208 void 2209 _M_erase_at_begin(iterator __pos) 2210 { 2211 _M_destroy_data(begin(), __pos, _M_get_Tp_allocator()); 2212 _M_destroy_nodes(this->_M_impl._M_start._M_node, __pos._M_node); 2213 this->_M_impl._M_start = __pos; 2214 } 2215 2216 // Called by erase(q1, q2), resize(), clear(), _M_assign_aux, 2217 // _M_fill_assign, operator=. 2218 void 2219 _M_erase_at_end(iterator __pos) 2220 { 2221 _M_destroy_data(__pos, end(), _M_get_Tp_allocator()); 2222 _M_destroy_nodes(__pos._M_node + 1, 2223 this->_M_impl._M_finish._M_node + 1); 2224 this->_M_impl._M_finish = __pos; 2225 } 2226 2227 iterator 2228 _M_erase(iterator __pos); 2229 2230 iterator 2231 _M_erase(iterator __first, iterator __last); 2232 2233 #if __cplusplus >= 201103L 2234 // Called by resize(sz). 2235 void 2236 _M_default_append(size_type __n); 2237 2238 bool 2239 _M_shrink_to_fit(); 2240 #endif 2241 2242 ///@{ 2243 /// Memory-handling helpers for the previous internal insert functions. 2244 iterator 2245 _M_reserve_elements_at_front(size_type __n) 2246 { 2247 const size_type __vacancies = this->_M_impl._M_start._M_cur 2248 - this->_M_impl._M_start._M_first; 2249 if (__n > __vacancies) 2250 _M_new_elements_at_front(__n - __vacancies); 2251 return this->_M_impl._M_start - difference_type(__n); 2252 } 2253 2254 iterator 2255 _M_reserve_elements_at_back(size_type __n) 2256 { 2257 const size_type __vacancies = (this->_M_impl._M_finish._M_last 2258 - this->_M_impl._M_finish._M_cur) - 1; 2259 if (__n > __vacancies) 2260 _M_new_elements_at_back(__n - __vacancies); 2261 return this->_M_impl._M_finish + difference_type(__n); 2262 } 2263 2264 void 2265 _M_new_elements_at_front(size_type __new_elements); 2266 2267 void 2268 _M_new_elements_at_back(size_type __new_elements); 2269 ///@} 2270 2271 2272 ///@{ 2273 /** 2274 * @brief Memory-handling helpers for the major %map. 2275 * 2276 * Makes sure the _M_map has space for new nodes. Does not 2277 * actually add the nodes. Can invalidate _M_map pointers. 2278 * (And consequently, %deque iterators.) 2279 */ 2280 void 2281 _M_reserve_map_at_back(size_type __nodes_to_add = 1) 2282 { 2283 if (__nodes_to_add + 1 > this->_M_impl._M_map_size 2284 - (this->_M_impl._M_finish._M_node - this->_M_impl._M_map)) 2285 _M_reallocate_map(__nodes_to_add, false); 2286 } 2287 2288 void 2289 _M_reserve_map_at_front(size_type __nodes_to_add = 1) 2290 { 2291 if (__nodes_to_add > size_type(this->_M_impl._M_start._M_node 2292 - this->_M_impl._M_map)) 2293 _M_reallocate_map(__nodes_to_add, true); 2294 } 2295 2296 void 2297 _M_reallocate_map(size_type __nodes_to_add, bool __add_at_front); 2298 ///@} 2299 2300 #if __cplusplus >= 201103L 2301 // Constant-time, nothrow move assignment when source object's memory 2302 // can be moved because the allocators are equal. 2303 void 2304 _M_move_assign1(deque&& __x, /* always equal: */ true_type) noexcept 2305 { 2306 this->_M_impl._M_swap_data(__x._M_impl); 2307 __x.clear(); 2308 std::__alloc_on_move(_M_get_Tp_allocator(), __x._M_get_Tp_allocator()); 2309 } 2310 2311 // When the allocators are not equal the operation could throw, because 2312 // we might need to allocate a new map for __x after moving from it 2313 // or we might need to allocate new elements for *this. 2314 void 2315 _M_move_assign1(deque&& __x, /* always equal: */ false_type) 2316 { 2317 if (_M_get_Tp_allocator() == __x._M_get_Tp_allocator()) 2318 return _M_move_assign1(std::move(__x), true_type()); 2319 2320 constexpr bool __move_storage = 2321 _Alloc_traits::_S_propagate_on_move_assign(); 2322 _M_move_assign2(std::move(__x), __bool_constant<__move_storage>()); 2323 } 2324 2325 // Destroy all elements and deallocate all memory, then replace 2326 // with elements created from __args. 2327 template<typename... _Args> 2328 void 2329 _M_replace_map(_Args&&... __args) 2330 { 2331 // Create new data first, so if allocation fails there are no effects. 2332 deque __newobj(std::forward<_Args>(__args)...); 2333 // Free existing storage using existing allocator. 2334 clear(); 2335 _M_deallocate_node(*begin()._M_node); // one node left after clear() 2336 _M_deallocate_map(this->_M_impl._M_map, this->_M_impl._M_map_size); 2337 this->_M_impl._M_map = nullptr; 2338 this->_M_impl._M_map_size = 0; 2339 // Take ownership of replacement memory. 2340 this->_M_impl._M_swap_data(__newobj._M_impl); 2341 } 2342 2343 // Do move assignment when the allocator propagates. 2344 void 2345 _M_move_assign2(deque&& __x, /* propagate: */ true_type) 2346 { 2347 // Make a copy of the original allocator state. 2348 auto __alloc = __x._M_get_Tp_allocator(); 2349 // The allocator propagates so storage can be moved from __x, 2350 // leaving __x in a valid empty state with a moved-from allocator. 2351 _M_replace_map(std::move(__x)); 2352 // Move the corresponding allocator state too. 2353 _M_get_Tp_allocator() = std::move(__alloc); 2354 } 2355 2356 // Do move assignment when it may not be possible to move source 2357 // object's memory, resulting in a linear-time operation. 2358 void 2359 _M_move_assign2(deque&& __x, /* propagate: */ false_type) 2360 { 2361 if (__x._M_get_Tp_allocator() == this->_M_get_Tp_allocator()) 2362 { 2363 // The allocators are equal so storage can be moved from __x, 2364 // leaving __x in a valid empty state with its current allocator. 2365 _M_replace_map(std::move(__x), __x.get_allocator()); 2366 } 2367 else 2368 { 2369 // The rvalue's allocator cannot be moved and is not equal, 2370 // so we need to individually move each element. 2371 _M_assign_aux(std::make_move_iterator(__x.begin()), 2372 std::make_move_iterator(__x.end()), 2373 std::random_access_iterator_tag()); 2374 __x.clear(); 2375 } 2376 } 2377 #endif 2378 }; 2379 2380 #if __cpp_deduction_guides >= 201606 2381 template<typename _InputIterator, typename _ValT 2382 = typename iterator_traits<_InputIterator>::value_type, 2383 typename _Allocator = allocator<_ValT>, 2384 typename = _RequireInputIter<_InputIterator>, 2385 typename = _RequireAllocator<_Allocator>> 2386 deque(_InputIterator, _InputIterator, _Allocator = _Allocator()) 2387 -> deque<_ValT, _Allocator>; 2388 2389 #if __glibcxx_containers_ranges // C++ >= 23 2390 template<ranges::input_range _Rg, 2391 typename _Alloc = allocator<ranges::range_value_t<_Rg>>> 2392 deque(from_range_t, _Rg&&, _Alloc = _Alloc()) 2393 -> deque<ranges::range_value_t<_Rg>, _Alloc>; 2394 #endif 2395 #endif 2396 2397 /** 2398 * @brief Deque equality comparison. 2399 * @param __x A %deque. 2400 * @param __y A %deque of the same type as @a __x. 2401 * @return True iff the size and elements of the deques are equal. 2402 * 2403 * This is an equivalence relation. It is linear in the size of the 2404 * deques. Deques are considered equivalent if their sizes are equal, 2405 * and if corresponding elements compare equal. 2406 */ 2407 template<typename _Tp, typename _Alloc> 2408 _GLIBCXX_NODISCARD 2409 inline bool 2410 operator==(const deque<_Tp, _Alloc>& __x, const deque<_Tp, _Alloc>& __y) 2411 { return __x.size() == __y.size() 2412 && std::equal(__x.begin(), __x.end(), __y.begin()); } 2413 2414 #if __cpp_lib_three_way_comparison 2415 /** 2416 * @brief Deque ordering relation. 2417 * @param __x A `deque`. 2418 * @param __y A `deque` of the same type as `__x`. 2419 * @return A value indicating whether `__x` is less than, equal to, 2420 * greater than, or incomparable with `__y`. 2421 * 2422 * See `std::lexicographical_compare_three_way()` for how the determination 2423 * is made. This operator is used to synthesize relational operators like 2424 * `<` and `>=` etc. 2425 */ 2426 template<typename _Tp, typename _Alloc> 2427 [[nodiscard]] 2428 inline __detail::__synth3way_t<_Tp> 2429 operator<=>(const deque<_Tp, _Alloc>& __x, const deque<_Tp, _Alloc>& __y) 2430 { 2431 return std::lexicographical_compare_three_way(__x.begin(), __x.end(), 2432 __y.begin(), __y.end(), 2433 __detail::__synth3way); 2434 } 2435 #else 2436 /** 2437 * @brief Deque ordering relation. 2438 * @param __x A %deque. 2439 * @param __y A %deque of the same type as @a __x. 2440 * @return True iff @a x is lexicographically less than @a __y. 2441 * 2442 * This is a total ordering relation. It is linear in the size of the 2443 * deques. The elements must be comparable with @c <. 2444 * 2445 * See std::lexicographical_compare() for how the determination is made. 2446 */ 2447 template<typename _Tp, typename _Alloc> 2448 _GLIBCXX_NODISCARD 2449 inline bool 2450 operator<(const deque<_Tp, _Alloc>& __x, const deque<_Tp, _Alloc>& __y) 2451 { return std::lexicographical_compare(__x.begin(), __x.end(), 2452 __y.begin(), __y.end()); } 2453 2454 /// Based on operator== 2455 template<typename _Tp, typename _Alloc> 2456 _GLIBCXX_NODISCARD 2457 inline bool 2458 operator!=(const deque<_Tp, _Alloc>& __x, const deque<_Tp, _Alloc>& __y) 2459 { return !(__x == __y); } 2460 2461 /// Based on operator< 2462 template<typename _Tp, typename _Alloc> 2463 _GLIBCXX_NODISCARD 2464 inline bool 2465 operator>(const deque<_Tp, _Alloc>& __x, const deque<_Tp, _Alloc>& __y) 2466 { return __y < __x; } 2467 2468 /// Based on operator< 2469 template<typename _Tp, typename _Alloc> 2470 _GLIBCXX_NODISCARD 2471 inline bool 2472 operator<=(const deque<_Tp, _Alloc>& __x, const deque<_Tp, _Alloc>& __y) 2473 { return !(__y < __x); } 2474 2475 /// Based on operator< 2476 template<typename _Tp, typename _Alloc> 2477 _GLIBCXX_NODISCARD 2478 inline bool 2479 operator>=(const deque<_Tp, _Alloc>& __x, const deque<_Tp, _Alloc>& __y) 2480 { return !(__x < __y); } 2481 #endif // three-way comparison 2482 2483 /// See std::deque::swap(). 2484 template<typename _Tp, typename _Alloc> 2485 inline void 2486 swap(deque<_Tp,_Alloc>& __x, deque<_Tp,_Alloc>& __y) 2487 _GLIBCXX_NOEXCEPT_IF(noexcept(__x.swap(__y))) 2488 { __x.swap(__y); } 2489 2490 #undef _GLIBCXX_DEQUE_BUF_SIZE 2491 2492 _GLIBCXX_END_NAMESPACE_CONTAINER 2493 2494 #if __cplusplus >= 201103L 2495 // std::allocator is safe, but it is not the only allocator 2496 // for which this is valid. 2497 template<class _Tp> 2498 struct __is_bitwise_relocatable<_GLIBCXX_STD_C::deque<_Tp>> 2499 : true_type { }; 2500 #endif 2501 2502 _GLIBCXX_END_NAMESPACE_VERSION 2503 } // namespace std 2504 2505 #endif /* _STL_DEQUE_H */
