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