libstdc++
stl_deque.h
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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>
62#if __cplusplus >= 201103L
63#include <initializer_list>
64#include <bits/stl_uninitialized.h> // for __is_bitwise_relocatable
65#endif
66
67#include <debug/assertions.h>
68
69namespace std _GLIBCXX_VISIBILITY(default)
70{
71_GLIBCXX_BEGIN_NAMESPACE_VERSION
72_GLIBCXX_BEGIN_NAMESPACE_CONTAINER
73
74 /**
75 * @brief This function controls the size of memory nodes.
76 * @param __size The size of an element.
77 * @return The number (not byte size) of elements per node.
78 *
79 * This function started off as a compiler kludge from SGI, but
80 * seems to be a useful wrapper around a repeated constant
81 * expression. The @b 512 is tunable (and no other code needs to
82 * change), but no investigation has been done since inheriting the
83 * SGI code. Touch _GLIBCXX_DEQUE_BUF_SIZE only if you know what
84 * you are doing, however: changing it breaks the binary
85 * compatibility!!
86 */
87
88#ifndef _GLIBCXX_DEQUE_BUF_SIZE
89#define _GLIBCXX_DEQUE_BUF_SIZE 512
90#endif
91
92 _GLIBCXX_CONSTEXPR inline size_t
93 __deque_buf_size(size_t __size)
94 { return (__size < _GLIBCXX_DEQUE_BUF_SIZE
95 ? size_t(_GLIBCXX_DEQUE_BUF_SIZE / __size) : size_t(1)); }
96
97
98 /**
99 * @brief A deque::iterator.
100 *
101 * Quite a bit of intelligence here. Much of the functionality of
102 * deque is actually passed off to this class. A deque holds two
103 * of these internally, marking its valid range. Access to
104 * elements is done as offsets of either of those two, relying on
105 * operator overloading in this class.
106 *
107 * All the functions are op overloads except for _M_set_node.
108 */
109 template<typename _Tp, typename _Ref, typename _Ptr>
111 {
112#if __cplusplus < 201103L
115 typedef _Tp* _Elt_pointer;
116 typedef _Tp** _Map_pointer;
117#else
118 private:
119 template<typename _CvTp>
121 public:
122 typedef __iter<_Tp> iterator;
124 typedef __ptr_rebind<_Ptr, _Tp> _Elt_pointer;
125 typedef __ptr_rebind<_Ptr, _Elt_pointer> _Map_pointer;
126#endif
127
128 static size_t _S_buffer_size() _GLIBCXX_NOEXCEPT
129 { return __deque_buf_size(sizeof(_Tp)); }
130
132 typedef _Tp value_type;
133 typedef _Ptr pointer;
134 typedef _Ref reference;
135 typedef size_t size_type;
136 typedef ptrdiff_t difference_type;
137 typedef _Deque_iterator _Self;
138
139 _Elt_pointer _M_cur;
140 _Elt_pointer _M_first;
141 _Elt_pointer _M_last;
142 _Map_pointer _M_node;
143
144 _Deque_iterator(_Elt_pointer __x, _Map_pointer __y) _GLIBCXX_NOEXCEPT
145 : _M_cur(__x), _M_first(*__y),
146 _M_last(*__y + _S_buffer_size()), _M_node(__y) { }
147
148 _Deque_iterator() _GLIBCXX_NOEXCEPT
149 : _M_cur(), _M_first(), _M_last(), _M_node() { }
150
151#if __cplusplus < 201103L
152 // Conversion from iterator to const_iterator.
153 _Deque_iterator(const iterator& __x) _GLIBCXX_NOEXCEPT
154 : _M_cur(__x._M_cur), _M_first(__x._M_first),
155 _M_last(__x._M_last), _M_node(__x._M_node) { }
156#else
157 // Conversion from iterator to const_iterator.
158 template<typename _Iter,
159 typename = _Require<is_same<_Self, const_iterator>,
161 _Deque_iterator(const _Iter& __x) noexcept
162 : _M_cur(__x._M_cur), _M_first(__x._M_first),
163 _M_last(__x._M_last), _M_node(__x._M_node) { }
164
165 _Deque_iterator(const _Deque_iterator& __x) noexcept
166 : _M_cur(__x._M_cur), _M_first(__x._M_first),
167 _M_last(__x._M_last), _M_node(__x._M_node) { }
168
169 _Deque_iterator& operator=(const _Deque_iterator&) = default;
170#endif
171
173 _M_const_cast() const _GLIBCXX_NOEXCEPT
174 { return iterator(_M_cur, _M_node); }
175
176 reference
177 operator*() const _GLIBCXX_NOEXCEPT
178 { return *_M_cur; }
179
180 pointer
181 operator->() const _GLIBCXX_NOEXCEPT
182 { return _M_cur; }
183
184 _Self&
185 operator++() _GLIBCXX_NOEXCEPT
186 {
187 ++_M_cur;
188 if (_M_cur == _M_last)
189 {
190 _M_set_node(_M_node + 1);
191 _M_cur = _M_first;
192 }
193 return *this;
194 }
195
196 _Self
197 operator++(int) _GLIBCXX_NOEXCEPT
198 {
199 _Self __tmp = *this;
200 ++*this;
201 return __tmp;
202 }
203
204 _Self&
205 operator--() _GLIBCXX_NOEXCEPT
206 {
207 if (_M_cur == _M_first)
208 {
209 _M_set_node(_M_node - 1);
210 _M_cur = _M_last;
211 }
212 --_M_cur;
213 return *this;
214 }
215
216 _Self
217 operator--(int) _GLIBCXX_NOEXCEPT
218 {
219 _Self __tmp = *this;
220 --*this;
221 return __tmp;
222 }
223
224 _Self&
225 operator+=(difference_type __n) _GLIBCXX_NOEXCEPT
226 {
227 const difference_type __offset = __n + (_M_cur - _M_first);
228 if (__offset >= 0 && __offset < difference_type(_S_buffer_size()))
229 _M_cur += __n;
230 else
231 {
232 const difference_type __node_offset =
233 __offset > 0 ? __offset / difference_type(_S_buffer_size())
234 : -difference_type((-__offset - 1)
235 / _S_buffer_size()) - 1;
236 _M_set_node(_M_node + __node_offset);
237 _M_cur = _M_first + (__offset - __node_offset
238 * difference_type(_S_buffer_size()));
239 }
240 return *this;
241 }
242
243 _Self&
244 operator-=(difference_type __n) _GLIBCXX_NOEXCEPT
245 { return *this += -__n; }
246
247 reference
248 operator[](difference_type __n) const _GLIBCXX_NOEXCEPT
249 { return *(*this + __n); }
250
251 /**
252 * Prepares to traverse new_node. Sets everything except
253 * _M_cur, which should therefore be set by the caller
254 * immediately afterwards, based on _M_first and _M_last.
255 */
256 void
257 _M_set_node(_Map_pointer __new_node) _GLIBCXX_NOEXCEPT
258 {
259 _M_node = __new_node;
260 _M_first = *__new_node;
261 _M_last = _M_first + difference_type(_S_buffer_size());
262 }
263
264 friend bool
265 operator==(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT
266 { return __x._M_cur == __y._M_cur; }
267
268 // Note: we also provide overloads whose operands are of the same type in
269 // order to avoid ambiguous overload resolution when std::rel_ops operators
270 // are in scope (for additional details, see libstdc++/3628)
271 template<typename _RefR, typename _PtrR>
272 friend bool
273 operator==(const _Self& __x,
274 const _Deque_iterator<_Tp, _RefR, _PtrR>& __y) _GLIBCXX_NOEXCEPT
275 { return __x._M_cur == __y._M_cur; }
276
277 friend bool
278 operator!=(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT
279 { return !(__x == __y); }
280
281 template<typename _RefR, typename _PtrR>
282 friend bool
283 operator!=(const _Self& __x,
284 const _Deque_iterator<_Tp, _RefR, _PtrR>& __y) _GLIBCXX_NOEXCEPT
285 { return !(__x == __y); }
286
287 friend bool
288 operator<(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT
289 {
290 return (__x._M_node == __y._M_node)
291 ? (__x._M_cur < __y._M_cur) : (__x._M_node < __y._M_node);
292 }
293
294 template<typename _RefR, typename _PtrR>
295 friend bool
296 operator<(const _Self& __x,
297 const _Deque_iterator<_Tp, _RefR, _PtrR>& __y) _GLIBCXX_NOEXCEPT
298 {
299 return (__x._M_node == __y._M_node)
300 ? (__x._M_cur < __y._M_cur) : (__x._M_node < __y._M_node);
301 }
302
303 friend bool
304 operator>(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT
305 { return __y < __x; }
306
307 template<typename _RefR, typename _PtrR>
308 friend bool
309 operator>(const _Self& __x,
310 const _Deque_iterator<_Tp, _RefR, _PtrR>& __y) _GLIBCXX_NOEXCEPT
311 { return __y < __x; }
312
313 friend bool
314 operator<=(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT
315 { return !(__y < __x); }
316
317 template<typename _RefR, typename _PtrR>
318 friend bool
319 operator<=(const _Self& __x,
320 const _Deque_iterator<_Tp, _RefR, _PtrR>& __y) _GLIBCXX_NOEXCEPT
321 { return !(__y < __x); }
322
323 friend bool
324 operator>=(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT
325 { return !(__x < __y); }
326
327 template<typename _RefR, typename _PtrR>
328 friend bool
329 operator>=(const _Self& __x,
330 const _Deque_iterator<_Tp, _RefR, _PtrR>& __y) _GLIBCXX_NOEXCEPT
331 { return !(__x < __y); }
332
333 friend difference_type
334 operator-(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT
335 {
336 return difference_type(_S_buffer_size())
337 * (__x._M_node - __y._M_node - 1) + (__x._M_cur - __x._M_first)
338 + (__y._M_last - __y._M_cur);
339 }
340
341 // _GLIBCXX_RESOLVE_LIB_DEFECTS
342 // According to the resolution of DR179 not only the various comparison
343 // operators but also operator- must accept mixed iterator/const_iterator
344 // parameters.
345 template<typename _RefR, typename _PtrR>
346 friend difference_type
347 operator-(const _Self& __x,
348 const _Deque_iterator<_Tp, _RefR, _PtrR>& __y) _GLIBCXX_NOEXCEPT
349 {
350 return difference_type(_S_buffer_size())
351 * (__x._M_node - __y._M_node - 1) + (__x._M_cur - __x._M_first)
352 + (__y._M_last - __y._M_cur);
353 }
354
355 friend _Self
356 operator+(const _Self& __x, difference_type __n) _GLIBCXX_NOEXCEPT
357 {
358 _Self __tmp = __x;
359 __tmp += __n;
360 return __tmp;
361 }
362
363 friend _Self
364 operator-(const _Self& __x, difference_type __n) _GLIBCXX_NOEXCEPT
365 {
366 _Self __tmp = __x;
367 __tmp -= __n;
368 return __tmp;
369 }
370
371 friend _Self
372 operator+(difference_type __n, const _Self& __x) _GLIBCXX_NOEXCEPT
373 { return __x + __n; }
374 };
375
376 /**
377 * Deque base class. This class provides the unified face for %deque's
378 * allocation. This class's constructor and destructor allocate and
379 * deallocate (but do not initialize) storage. This makes %exception
380 * safety easier.
381 *
382 * Nothing in this class ever constructs or destroys an actual Tp element.
383 * (Deque handles that itself.) Only/All memory management is performed
384 * here.
385 */
386 template<typename _Tp, typename _Alloc>
388 {
389 protected:
391 rebind<_Tp>::other _Tp_alloc_type;
393
394#if __cplusplus < 201103L
395 typedef _Tp* _Ptr;
396 typedef const _Tp* _Ptr_const;
397#else
398 typedef typename _Alloc_traits::pointer _Ptr;
399 typedef typename _Alloc_traits::const_pointer _Ptr_const;
400#endif
401
402 typedef typename _Alloc_traits::template rebind<_Ptr>::other
403 _Map_alloc_type;
405
406 typedef _Alloc allocator_type;
407
408 allocator_type
409 get_allocator() const _GLIBCXX_NOEXCEPT
410 { return allocator_type(_M_get_Tp_allocator()); }
411
414
416 : _M_impl()
417 { _M_initialize_map(0); }
418
419 _Deque_base(size_t __num_elements)
420 : _M_impl()
421 { _M_initialize_map(__num_elements); }
422
423 _Deque_base(const allocator_type& __a, size_t __num_elements)
424 : _M_impl(__a)
425 { _M_initialize_map(__num_elements); }
426
427 _Deque_base(const allocator_type& __a)
428 : _M_impl(__a)
429 { /* Caller must initialize map. */ }
430
431#if __cplusplus >= 201103L
433 : _M_impl(std::move(__x._M_get_Tp_allocator()))
434 {
436 if (__x._M_impl._M_map)
437 this->_M_impl._M_swap_data(__x._M_impl);
438 }
439
440 _Deque_base(_Deque_base&& __x, const allocator_type& __a)
441 : _M_impl(std::move(__x._M_impl), _Tp_alloc_type(__a))
442 { __x._M_initialize_map(0); }
443
444 _Deque_base(_Deque_base&& __x, const allocator_type& __a, size_t __n)
445 : _M_impl(__a)
446 {
447 if (__x.get_allocator() == __a)
448 {
449 if (__x._M_impl._M_map)
450 {
452 this->_M_impl._M_swap_data(__x._M_impl);
453 }
454 }
455 else
456 {
458 }
459 }
460#endif
461
462 ~_Deque_base() _GLIBCXX_NOEXCEPT;
463
464 typedef typename iterator::_Map_pointer _Map_pointer;
465
466 struct _Deque_impl_data
467 {
468 _Map_pointer _M_map;
469 size_t _M_map_size;
470 iterator _M_start;
471 iterator _M_finish;
472
473 _Deque_impl_data() _GLIBCXX_NOEXCEPT
474 : _M_map(), _M_map_size(), _M_start(), _M_finish()
475 { }
476
477#if __cplusplus >= 201103L
478 _Deque_impl_data(const _Deque_impl_data&) = default;
479 _Deque_impl_data&
480 operator=(const _Deque_impl_data&) = default;
481
482 _Deque_impl_data(_Deque_impl_data&& __x) noexcept
483 : _Deque_impl_data(__x)
484 { __x = _Deque_impl_data(); }
485#endif
486
487 void
488 _M_swap_data(_Deque_impl_data& __x) _GLIBCXX_NOEXCEPT
489 {
490 // Do not use std::swap(_M_start, __x._M_start), etc as it loses
491 // information used by TBAA.
492 std::swap(*this, __x);
493 }
494 };
495
496 // This struct encapsulates the implementation of the std::deque
497 // standard container and at the same time makes use of the EBO
498 // for empty allocators.
499 struct _Deque_impl
500 : public _Tp_alloc_type, public _Deque_impl_data
501 {
502 _Deque_impl() _GLIBCXX_NOEXCEPT_IF(
504 : _Tp_alloc_type()
505 { }
506
507 _Deque_impl(const _Tp_alloc_type& __a) _GLIBCXX_NOEXCEPT
508 : _Tp_alloc_type(__a)
509 { }
510
511#if __cplusplus >= 201103L
512 _Deque_impl(_Deque_impl&&) = default;
513
514 _Deque_impl(_Tp_alloc_type&& __a) noexcept
515 : _Tp_alloc_type(std::move(__a))
516 { }
517
518 _Deque_impl(_Deque_impl&& __d, _Tp_alloc_type&& __a)
519 : _Tp_alloc_type(std::move(__a)), _Deque_impl_data(std::move(__d))
520 { }
521#endif
522 };
523
524 _Tp_alloc_type&
525 _M_get_Tp_allocator() _GLIBCXX_NOEXCEPT
526 { return this->_M_impl; }
527
528 const _Tp_alloc_type&
529 _M_get_Tp_allocator() const _GLIBCXX_NOEXCEPT
530 { return this->_M_impl; }
531
532 _Map_alloc_type
533 _M_get_map_allocator() const _GLIBCXX_NOEXCEPT
534 { return _Map_alloc_type(_M_get_Tp_allocator()); }
535
536 _Ptr
537 _M_allocate_node()
538 {
540 return _Traits::allocate(_M_impl, __deque_buf_size(sizeof(_Tp)));
541 }
542
543 void
544 _M_deallocate_node(_Ptr __p) _GLIBCXX_NOEXCEPT
545 {
547 _Traits::deallocate(_M_impl, __p, __deque_buf_size(sizeof(_Tp)));
548 }
549
550 _Map_pointer
551 _M_allocate_map(size_t __n)
552 {
553 _Map_alloc_type __map_alloc = _M_get_map_allocator();
554 return _Map_alloc_traits::allocate(__map_alloc, __n);
555 }
556
557 void
558 _M_deallocate_map(_Map_pointer __p, size_t __n) _GLIBCXX_NOEXCEPT
559 {
560 _Map_alloc_type __map_alloc = _M_get_map_allocator();
561 _Map_alloc_traits::deallocate(__map_alloc, __p, __n);
562 }
563
564 void _M_initialize_map(size_t);
565 void _M_create_nodes(_Map_pointer __nstart, _Map_pointer __nfinish);
566 void _M_destroy_nodes(_Map_pointer __nstart,
567 _Map_pointer __nfinish) _GLIBCXX_NOEXCEPT;
568 enum { _S_initial_map_size = 8 };
569
570 _Deque_impl _M_impl;
571 };
572
573 template<typename _Tp, typename _Alloc>
574 _Deque_base<_Tp, _Alloc>::
575 ~_Deque_base() _GLIBCXX_NOEXCEPT
576 {
577 if (this->_M_impl._M_map)
578 {
579 _M_destroy_nodes(this->_M_impl._M_start._M_node,
580 this->_M_impl._M_finish._M_node + 1);
581 _M_deallocate_map(this->_M_impl._M_map, this->_M_impl._M_map_size);
582 }
583 }
584
585 /**
586 * @brief Layout storage.
587 * @param __num_elements The count of T's for which to allocate space
588 * at first.
589 * @return Nothing.
590 *
591 * The initial underlying memory layout is a bit complicated...
592 */
593 template<typename _Tp, typename _Alloc>
594 void
596 _M_initialize_map(size_t __num_elements)
597 {
598 const size_t __num_nodes = (__num_elements / __deque_buf_size(sizeof(_Tp))
599 + 1);
600
601 this->_M_impl._M_map_size = std::max((size_t) _S_initial_map_size,
602 size_t(__num_nodes + 2));
603 this->_M_impl._M_map = _M_allocate_map(this->_M_impl._M_map_size);
604
605 // For "small" maps (needing less than _M_map_size nodes), allocation
606 // starts in the middle elements and grows outwards. So nstart may be
607 // the beginning of _M_map, but for small maps it may be as far in as
608 // _M_map+3.
609
610 _Map_pointer __nstart = (this->_M_impl._M_map
611 + (this->_M_impl._M_map_size - __num_nodes) / 2);
612 _Map_pointer __nfinish = __nstart + __num_nodes;
613
614 __try
615 { _M_create_nodes(__nstart, __nfinish); }
616 __catch(...)
617 {
618 _M_deallocate_map(this->_M_impl._M_map, this->_M_impl._M_map_size);
619 this->_M_impl._M_map = _Map_pointer();
620 this->_M_impl._M_map_size = 0;
621 __throw_exception_again;
622 }
623
624 this->_M_impl._M_start._M_set_node(__nstart);
625 this->_M_impl._M_finish._M_set_node(__nfinish - 1);
626 this->_M_impl._M_start._M_cur = _M_impl._M_start._M_first;
627 this->_M_impl._M_finish._M_cur = (this->_M_impl._M_finish._M_first
628 + __num_elements
629 % __deque_buf_size(sizeof(_Tp)));
630 }
631
632 template<typename _Tp, typename _Alloc>
633 void
635 _M_create_nodes(_Map_pointer __nstart, _Map_pointer __nfinish)
636 {
637 _Map_pointer __cur;
638 __try
639 {
640 for (__cur = __nstart; __cur < __nfinish; ++__cur)
641 *__cur = this->_M_allocate_node();
642 }
643 __catch(...)
644 {
645 _M_destroy_nodes(__nstart, __cur);
646 __throw_exception_again;
647 }
648 }
649
650 template<typename _Tp, typename _Alloc>
651 void
652 _Deque_base<_Tp, _Alloc>::
653 _M_destroy_nodes(_Map_pointer __nstart,
654 _Map_pointer __nfinish) _GLIBCXX_NOEXCEPT
655 {
656 for (_Map_pointer __n = __nstart; __n < __nfinish; ++__n)
657 _M_deallocate_node(*__n);
658 }
659
660 /**
661 * @brief A standard container using fixed-size memory allocation and
662 * constant-time manipulation of elements at either end.
663 *
664 * @ingroup sequences
665 *
666 * @tparam _Tp Type of element.
667 * @tparam _Alloc Allocator type, defaults to allocator<_Tp>.
668 *
669 * Meets the requirements of a <a href="tables.html#65">container</a>, a
670 * <a href="tables.html#66">reversible container</a>, and a
671 * <a href="tables.html#67">sequence</a>, including the
672 * <a href="tables.html#68">optional sequence requirements</a>.
673 *
674 * In previous HP/SGI versions of deque, there was an extra template
675 * parameter so users could control the node size. This extension turned
676 * out to violate the C++ standard (it can be detected using template
677 * template parameters), and it was removed.
678 *
679 * Here's how a deque<Tp> manages memory. Each deque has 4 members:
680 *
681 * - Tp** _M_map
682 * - size_t _M_map_size
683 * - iterator _M_start, _M_finish
684 *
685 * map_size is at least 8. %map is an array of map_size
686 * pointers-to-@a nodes. (The name %map has nothing to do with the
687 * std::map class, and @b nodes should not be confused with
688 * std::list's usage of @a node.)
689 *
690 * A @a node has no specific type name as such, but it is referred
691 * to as @a node in this file. It is a simple array-of-Tp. If Tp
692 * is very large, there will be one Tp element per node (i.e., an
693 * @a array of one). For non-huge Tp's, node size is inversely
694 * related to Tp size: the larger the Tp, the fewer Tp's will fit
695 * in a node. The goal here is to keep the total size of a node
696 * relatively small and constant over different Tp's, to improve
697 * allocator efficiency.
698 *
699 * Not every pointer in the %map array will point to a node. If
700 * the initial number of elements in the deque is small, the
701 * /middle/ %map pointers will be valid, and the ones at the edges
702 * will be unused. This same situation will arise as the %map
703 * grows: available %map pointers, if any, will be on the ends. As
704 * new nodes are created, only a subset of the %map's pointers need
705 * to be copied @a outward.
706 *
707 * Class invariants:
708 * - For any nonsingular iterator i:
709 * - i.node points to a member of the %map array. (Yes, you read that
710 * correctly: i.node does not actually point to a node.) The member of
711 * the %map array is what actually points to the node.
712 * - i.first == *(i.node) (This points to the node (first Tp element).)
713 * - i.last == i.first + node_size
714 * - i.cur is a pointer in the range [i.first, i.last). NOTE:
715 * the implication of this is that i.cur is always a dereferenceable
716 * pointer, even if i is a past-the-end iterator.
717 * - Start and Finish are always nonsingular iterators. NOTE: this
718 * means that an empty deque must have one node, a deque with <N
719 * elements (where N is the node buffer size) must have one node, a
720 * deque with N through (2N-1) elements must have two nodes, etc.
721 * - For every node other than start.node and finish.node, every
722 * element in the node is an initialized object. If start.node ==
723 * finish.node, then [start.cur, finish.cur) are initialized
724 * objects, and the elements outside that range are uninitialized
725 * storage. Otherwise, [start.cur, start.last) and [finish.first,
726 * finish.cur) are initialized objects, and [start.first, start.cur)
727 * and [finish.cur, finish.last) are uninitialized storage.
728 * - [%map, %map + map_size) is a valid, non-empty range.
729 * - [start.node, finish.node] is a valid range contained within
730 * [%map, %map + map_size).
731 * - A pointer in the range [%map, %map + map_size) points to an allocated
732 * node if and only if the pointer is in the range
733 * [start.node, finish.node].
734 *
735 * Here's the magic: nothing in deque is @b aware of the discontiguous
736 * storage!
737 *
738 * The memory setup and layout occurs in the parent, _Base, and the iterator
739 * class is entirely responsible for @a leaping from one node to the next.
740 * All the implementation routines for deque itself work only through the
741 * start and finish iterators. This keeps the routines simple and sane,
742 * and we can use other standard algorithms as well.
743 */
744 template<typename _Tp, typename _Alloc = std::allocator<_Tp> >
745 class deque : protected _Deque_base<_Tp, _Alloc>
746 {
747#ifdef _GLIBCXX_CONCEPT_CHECKS
748 // concept requirements
749 typedef typename _Alloc::value_type _Alloc_value_type;
750# if __cplusplus < 201103L
751 __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
752# endif
753 __glibcxx_class_requires2(_Tp, _Alloc_value_type, _SameTypeConcept)
754#endif
755
756#if __cplusplus >= 201103L
757 static_assert(is_same<typename remove_cv<_Tp>::type, _Tp>::value,
758 "std::deque must have a non-const, non-volatile value_type");
759# if __cplusplus > 201703L || defined __STRICT_ANSI__
761 "std::deque must have the same value_type as its allocator");
762# endif
763#endif
764
766 typedef typename _Base::_Tp_alloc_type _Tp_alloc_type;
767 typedef typename _Base::_Alloc_traits _Alloc_traits;
768 typedef typename _Base::_Map_pointer _Map_pointer;
769
770 public:
771 typedef _Tp value_type;
772 typedef typename _Alloc_traits::pointer pointer;
773 typedef typename _Alloc_traits::const_pointer const_pointer;
774 typedef typename _Alloc_traits::reference reference;
775 typedef typename _Alloc_traits::const_reference const_reference;
776 typedef typename _Base::iterator iterator;
777 typedef typename _Base::const_iterator const_iterator;
780 typedef size_t size_type;
781 typedef ptrdiff_t difference_type;
782 typedef _Alloc allocator_type;
783
784 private:
785 static size_t _S_buffer_size() _GLIBCXX_NOEXCEPT
786 { return __deque_buf_size(sizeof(_Tp)); }
787
788 // Functions controlling memory layout, and nothing else.
790 using _Base::_M_create_nodes;
791 using _Base::_M_destroy_nodes;
792 using _Base::_M_allocate_node;
793 using _Base::_M_deallocate_node;
794 using _Base::_M_allocate_map;
795 using _Base::_M_deallocate_map;
796 using _Base::_M_get_Tp_allocator;
797
798 /**
799 * A total of four data members accumulated down the hierarchy.
800 * May be accessed via _M_impl.*
801 */
802 using _Base::_M_impl;
803
804 public:
805 // [23.2.1.1] construct/copy/destroy
806 // (assign() and get_allocator() are also listed in this section)
807
808 /**
809 * @brief Creates a %deque with no elements.
810 */
811#if __cplusplus >= 201103L
812 deque() = default;
813#else
814 deque() { }
815#endif
816
817 /**
818 * @brief Creates a %deque with no elements.
819 * @param __a An allocator object.
820 */
821 explicit
822 deque(const allocator_type& __a)
823 : _Base(__a, 0) { }
824
825#if __cplusplus >= 201103L
826 /**
827 * @brief Creates a %deque with default constructed elements.
828 * @param __n The number of elements to initially create.
829 * @param __a An allocator.
830 *
831 * This constructor fills the %deque with @a n default
832 * constructed elements.
833 */
834 explicit
835 deque(size_type __n, const allocator_type& __a = allocator_type())
836 : _Base(__a, _S_check_init_len(__n, __a))
837 { _M_default_initialize(); }
838
839 /**
840 * @brief Creates a %deque with copies of an exemplar element.
841 * @param __n The number of elements to initially create.
842 * @param __value An element to copy.
843 * @param __a An allocator.
844 *
845 * This constructor fills the %deque with @a __n copies of @a __value.
846 */
847 deque(size_type __n, const value_type& __value,
848 const allocator_type& __a = allocator_type())
849 : _Base(__a, _S_check_init_len(__n, __a))
850 { _M_fill_initialize(__value); }
851#else
852 /**
853 * @brief Creates a %deque with copies of an exemplar element.
854 * @param __n The number of elements to initially create.
855 * @param __value An element to copy.
856 * @param __a An allocator.
857 *
858 * This constructor fills the %deque with @a __n copies of @a __value.
859 */
860 explicit
861 deque(size_type __n, const value_type& __value = value_type(),
862 const allocator_type& __a = allocator_type())
863 : _Base(__a, _S_check_init_len(__n, __a))
864 { _M_fill_initialize(__value); }
865#endif
866
867 /**
868 * @brief %Deque copy constructor.
869 * @param __x A %deque of identical element and allocator types.
870 *
871 * The newly-created %deque uses a copy of the allocator object used
872 * by @a __x (unless the allocator traits dictate a different object).
873 */
874 deque(const deque& __x)
875 : _Base(_Alloc_traits::_S_select_on_copy(__x._M_get_Tp_allocator()),
876 __x.size())
877 { std::__uninitialized_copy_a(__x.begin(), __x.end(),
878 this->_M_impl._M_start,
879 _M_get_Tp_allocator()); }
880
881#if __cplusplus >= 201103L
882 /**
883 * @brief %Deque move constructor.
884 *
885 * The newly-created %deque contains the exact contents of the
886 * moved instance.
887 * The contents of the moved instance are a valid, but unspecified
888 * %deque.
889 */
890 deque(deque&&) = default;
891
892 /// Copy constructor with alternative allocator
893 deque(const deque& __x, const allocator_type& __a)
894 : _Base(__a, __x.size())
895 { std::__uninitialized_copy_a(__x.begin(), __x.end(),
896 this->_M_impl._M_start,
897 _M_get_Tp_allocator()); }
898
899 /// Move constructor with alternative allocator
900 deque(deque&& __x, const allocator_type& __a)
901 : deque(std::move(__x), __a, typename _Alloc_traits::is_always_equal{})
902 { }
903
904 private:
905 deque(deque&& __x, const allocator_type& __a, true_type)
906 : _Base(std::move(__x), __a)
907 { }
908
909 deque(deque&& __x, const allocator_type& __a, false_type)
910 : _Base(std::move(__x), __a, __x.size())
911 {
912 if (__x.get_allocator() != __a && !__x.empty())
913 {
914 std::__uninitialized_move_a(__x.begin(), __x.end(),
915 this->_M_impl._M_start,
916 _M_get_Tp_allocator());
917 __x.clear();
918 }
919 }
920
921 public:
922 /**
923 * @brief Builds a %deque from an initializer list.
924 * @param __l An initializer_list.
925 * @param __a An allocator object.
926 *
927 * Create a %deque consisting of copies of the elements in the
928 * initializer_list @a __l.
929 *
930 * This will call the element type's copy constructor N times
931 * (where N is __l.size()) and do no memory reallocation.
932 */
934 const allocator_type& __a = allocator_type())
935 : _Base(__a)
936 {
937 _M_range_initialize(__l.begin(), __l.end(),
939 }
940#endif
941
942 /**
943 * @brief Builds a %deque from a range.
944 * @param __first An input iterator.
945 * @param __last An input iterator.
946 * @param __a An allocator object.
947 *
948 * Create a %deque consisting of copies of the elements from [__first,
949 * __last).
950 *
951 * If the iterators are forward, bidirectional, or random-access, then
952 * this will call the elements' copy constructor N times (where N is
953 * distance(__first,__last)) and do no memory reallocation. But if only
954 * input iterators are used, then this will do at most 2N calls to the
955 * copy constructor, and logN memory reallocations.
956 */
957#if __cplusplus >= 201103L
958 template<typename _InputIterator,
959 typename = std::_RequireInputIter<_InputIterator>>
960 deque(_InputIterator __first, _InputIterator __last,
961 const allocator_type& __a = allocator_type())
962 : _Base(__a)
963 {
964 _M_range_initialize(__first, __last,
965 std::__iterator_category(__first));
966 }
967#else
968 template<typename _InputIterator>
969 deque(_InputIterator __first, _InputIterator __last,
970 const allocator_type& __a = allocator_type())
971 : _Base(__a)
972 {
973 // Check whether it's an integral type. If so, it's not an iterator.
974 typedef typename std::__is_integer<_InputIterator>::__type _Integral;
975 _M_initialize_dispatch(__first, __last, _Integral());
976 }
977#endif
978
979 /**
980 * The dtor only erases the elements, and note that if the elements
981 * themselves are pointers, the pointed-to memory is not touched in any
982 * way. Managing the pointer is the user's responsibility.
983 */
985 { _M_destroy_data(begin(), end(), _M_get_Tp_allocator()); }
986
987 /**
988 * @brief %Deque assignment operator.
989 * @param __x A %deque of identical element and allocator types.
990 *
991 * All the elements of @a x are copied.
992 *
993 * The newly-created %deque uses a copy of the allocator object used
994 * by @a __x (unless the allocator traits dictate a different object).
995 */
996 deque&
997 operator=(const deque& __x);
998
999#if __cplusplus >= 201103L
1000 /**
1001 * @brief %Deque move assignment operator.
1002 * @param __x A %deque of identical element and allocator types.
1003 *
1004 * The contents of @a __x are moved into this deque (without copying,
1005 * if the allocators permit it).
1006 * @a __x is a valid, but unspecified %deque.
1007 */
1008 deque&
1009 operator=(deque&& __x) noexcept(_Alloc_traits::_S_always_equal())
1010 {
1011 using __always_equal = typename _Alloc_traits::is_always_equal;
1012 _M_move_assign1(std::move(__x), __always_equal{});
1013 return *this;
1014 }
1015
1016 /**
1017 * @brief Assigns an initializer list to a %deque.
1018 * @param __l An initializer_list.
1019 *
1020 * This function fills a %deque with copies of the elements in the
1021 * initializer_list @a __l.
1022 *
1023 * Note that the assignment completely changes the %deque and that the
1024 * resulting %deque's size is the same as the number of elements
1025 * assigned.
1026 */
1027 deque&
1029 {
1030 _M_assign_aux(__l.begin(), __l.end(),
1032 return *this;
1033 }
1034#endif
1035
1036 /**
1037 * @brief Assigns a given value to a %deque.
1038 * @param __n Number of elements to be assigned.
1039 * @param __val Value to be assigned.
1040 *
1041 * This function fills a %deque with @a n copies of the given
1042 * value. Note that the assignment completely changes the
1043 * %deque and that the resulting %deque's size is the same as
1044 * the number of elements assigned.
1045 */
1046 void
1047 assign(size_type __n, const value_type& __val)
1048 { _M_fill_assign(__n, __val); }
1049
1050 /**
1051 * @brief Assigns a range to a %deque.
1052 * @param __first An input iterator.
1053 * @param __last An input iterator.
1054 *
1055 * This function fills a %deque with copies of the elements in the
1056 * range [__first,__last).
1057 *
1058 * Note that the assignment completely changes the %deque and that the
1059 * resulting %deque's size is the same as the number of elements
1060 * assigned.
1061 */
1062#if __cplusplus >= 201103L
1063 template<typename _InputIterator,
1064 typename = std::_RequireInputIter<_InputIterator>>
1065 void
1066 assign(_InputIterator __first, _InputIterator __last)
1067 { _M_assign_aux(__first, __last, std::__iterator_category(__first)); }
1068#else
1069 template<typename _InputIterator>
1070 void
1071 assign(_InputIterator __first, _InputIterator __last)
1072 {
1073 typedef typename std::__is_integer<_InputIterator>::__type _Integral;
1074 _M_assign_dispatch(__first, __last, _Integral());
1075 }
1076#endif
1077
1078#if __cplusplus >= 201103L
1079 /**
1080 * @brief Assigns an initializer list to a %deque.
1081 * @param __l An initializer_list.
1082 *
1083 * This function fills a %deque with copies of the elements in the
1084 * initializer_list @a __l.
1085 *
1086 * Note that the assignment completely changes the %deque and that the
1087 * resulting %deque's size is the same as the number of elements
1088 * assigned.
1089 */
1090 void
1092 { _M_assign_aux(__l.begin(), __l.end(), random_access_iterator_tag()); }
1093#endif
1094
1095 /// Get a copy of the memory allocation object.
1096 allocator_type
1097 get_allocator() const _GLIBCXX_NOEXCEPT
1098 { return _Base::get_allocator(); }
1099
1100 // iterators
1101 /**
1102 * Returns a read/write iterator that points to the first element in the
1103 * %deque. Iteration is done in ordinary element order.
1104 */
1105 iterator
1106 begin() _GLIBCXX_NOEXCEPT
1107 { return this->_M_impl._M_start; }
1108
1109 /**
1110 * Returns a read-only (constant) iterator that points to the first
1111 * element in the %deque. Iteration is done in ordinary element order.
1112 */
1113 const_iterator
1114 begin() const _GLIBCXX_NOEXCEPT
1115 { return this->_M_impl._M_start; }
1116
1117 /**
1118 * Returns a read/write iterator that points one past the last
1119 * element in the %deque. Iteration is done in ordinary
1120 * element order.
1121 */
1122 iterator
1123 end() _GLIBCXX_NOEXCEPT
1124 { return this->_M_impl._M_finish; }
1125
1126 /**
1127 * Returns a read-only (constant) iterator that points one past
1128 * the last element in the %deque. Iteration is done in
1129 * ordinary element order.
1130 */
1131 const_iterator
1132 end() const _GLIBCXX_NOEXCEPT
1133 { return this->_M_impl._M_finish; }
1134
1135 /**
1136 * Returns a read/write reverse iterator that points to the
1137 * last element in the %deque. Iteration is done in reverse
1138 * element order.
1139 */
1141 rbegin() _GLIBCXX_NOEXCEPT
1142 { return reverse_iterator(this->_M_impl._M_finish); }
1143
1144 /**
1145 * Returns a read-only (constant) reverse iterator that points
1146 * to the last element in the %deque. Iteration is done in
1147 * reverse element order.
1148 */
1149 const_reverse_iterator
1150 rbegin() const _GLIBCXX_NOEXCEPT
1151 { return const_reverse_iterator(this->_M_impl._M_finish); }
1152
1153 /**
1154 * Returns a read/write reverse iterator that points to one
1155 * before the first element in the %deque. Iteration is done
1156 * in reverse element order.
1157 */
1159 rend() _GLIBCXX_NOEXCEPT
1160 { return reverse_iterator(this->_M_impl._M_start); }
1161
1162 /**
1163 * Returns a read-only (constant) reverse iterator that points
1164 * to one before the first element in the %deque. Iteration is
1165 * done in reverse element order.
1166 */
1167 const_reverse_iterator
1168 rend() const _GLIBCXX_NOEXCEPT
1169 { return const_reverse_iterator(this->_M_impl._M_start); }
1170
1171#if __cplusplus >= 201103L
1172 /**
1173 * Returns a read-only (constant) iterator that points to the first
1174 * element in the %deque. Iteration is done in ordinary element order.
1175 */
1176 const_iterator
1177 cbegin() const noexcept
1178 { return this->_M_impl._M_start; }
1179
1180 /**
1181 * Returns a read-only (constant) iterator that points one past
1182 * the last element in the %deque. Iteration is done in
1183 * ordinary element order.
1184 */
1185 const_iterator
1186 cend() const noexcept
1187 { return this->_M_impl._M_finish; }
1188
1189 /**
1190 * Returns a read-only (constant) reverse iterator that points
1191 * to the last element in the %deque. Iteration is done in
1192 * reverse element order.
1193 */
1194 const_reverse_iterator
1195 crbegin() const noexcept
1196 { return const_reverse_iterator(this->_M_impl._M_finish); }
1197
1198 /**
1199 * Returns a read-only (constant) reverse iterator that points
1200 * to one before the first element in the %deque. Iteration is
1201 * done in reverse element order.
1202 */
1203 const_reverse_iterator
1204 crend() const noexcept
1205 { return const_reverse_iterator(this->_M_impl._M_start); }
1206#endif
1207
1208 // [23.2.1.2] capacity
1209 /** Returns the number of elements in the %deque. */
1210 size_type
1211 size() const _GLIBCXX_NOEXCEPT
1212 { return this->_M_impl._M_finish - this->_M_impl._M_start; }
1213
1214 /** Returns the size() of the largest possible %deque. */
1215 size_type
1216 max_size() const _GLIBCXX_NOEXCEPT
1217 { return _S_max_size(_M_get_Tp_allocator()); }
1218
1219#if __cplusplus >= 201103L
1220 /**
1221 * @brief Resizes the %deque to the specified number of elements.
1222 * @param __new_size Number of elements the %deque should contain.
1223 *
1224 * This function will %resize the %deque to the specified
1225 * number of elements. If the number is smaller than the
1226 * %deque's current size the %deque is truncated, otherwise
1227 * default constructed elements are appended.
1228 */
1229 void
1230 resize(size_type __new_size)
1231 {
1232 const size_type __len = size();
1233 if (__new_size > __len)
1234 _M_default_append(__new_size - __len);
1235 else if (__new_size < __len)
1236 _M_erase_at_end(this->_M_impl._M_start
1237 + difference_type(__new_size));
1238 }
1239
1240 /**
1241 * @brief Resizes the %deque to the specified number of elements.
1242 * @param __new_size Number of elements the %deque should contain.
1243 * @param __x Data with which new elements should be populated.
1244 *
1245 * This function will %resize the %deque to the specified
1246 * number of elements. If the number is smaller than the
1247 * %deque's current size the %deque is truncated, otherwise the
1248 * %deque is extended and new elements are populated with given
1249 * data.
1250 */
1251 void
1252 resize(size_type __new_size, const value_type& __x)
1253#else
1254 /**
1255 * @brief Resizes the %deque to the specified number of elements.
1256 * @param __new_size Number of elements the %deque should contain.
1257 * @param __x Data with which new elements should be populated.
1258 *
1259 * This function will %resize the %deque to the specified
1260 * number of elements. If the number is smaller than the
1261 * %deque's current size the %deque is truncated, otherwise the
1262 * %deque is extended and new elements are populated with given
1263 * data.
1264 */
1265 void
1266 resize(size_type __new_size, value_type __x = value_type())
1267#endif
1268 {
1269 const size_type __len = size();
1270 if (__new_size > __len)
1271 _M_fill_insert(this->_M_impl._M_finish, __new_size - __len, __x);
1272 else if (__new_size < __len)
1273 _M_erase_at_end(this->_M_impl._M_start
1274 + difference_type(__new_size));
1275 }
1276
1277#if __cplusplus >= 201103L
1278 /** A non-binding request to reduce memory use. */
1279 void
1280 shrink_to_fit() noexcept
1281 { _M_shrink_to_fit(); }
1282#endif
1283
1284 /**
1285 * Returns true if the %deque is empty. (Thus begin() would
1286 * equal end().)
1287 */
1288 _GLIBCXX_NODISCARD bool
1289 empty() const _GLIBCXX_NOEXCEPT
1290 { return this->_M_impl._M_finish == this->_M_impl._M_start; }
1291
1292 // element access
1293 /**
1294 * @brief Subscript access to the data contained in the %deque.
1295 * @param __n The index of the element for which data should be
1296 * accessed.
1297 * @return Read/write reference to data.
1298 *
1299 * This operator allows for easy, array-style, data access.
1300 * Note that data access with this operator is unchecked and
1301 * out_of_range lookups are not defined. (For checked lookups
1302 * see at().)
1303 */
1304 reference
1305 operator[](size_type __n) _GLIBCXX_NOEXCEPT
1306 {
1307 __glibcxx_requires_subscript(__n);
1308 return this->_M_impl._M_start[difference_type(__n)];
1309 }
1310
1311 /**
1312 * @brief Subscript access to the data contained in the %deque.
1313 * @param __n The index of the element for which data should be
1314 * accessed.
1315 * @return Read-only (constant) reference to data.
1316 *
1317 * This operator allows for easy, array-style, data access.
1318 * Note that data access with this operator is unchecked and
1319 * out_of_range lookups are not defined. (For checked lookups
1320 * see at().)
1321 */
1322 const_reference
1323 operator[](size_type __n) const _GLIBCXX_NOEXCEPT
1324 {
1325 __glibcxx_requires_subscript(__n);
1326 return this->_M_impl._M_start[difference_type(__n)];
1327 }
1328
1329 protected:
1330 /// Safety check used only from at().
1331 void
1332 _M_range_check(size_type __n) const
1333 {
1334 if (__n >= this->size())
1335 __throw_out_of_range_fmt(__N("deque::_M_range_check: __n "
1336 "(which is %zu)>= this->size() "
1337 "(which is %zu)"),
1338 __n, this->size());
1339 }
1340
1341 public:
1342 /**
1343 * @brief Provides access to the data contained in the %deque.
1344 * @param __n The index of the element for which data should be
1345 * accessed.
1346 * @return Read/write reference to data.
1347 * @throw std::out_of_range If @a __n is an invalid index.
1348 *
1349 * This function provides for safer data access. The parameter
1350 * is first checked that it is in the range of the deque. The
1351 * function throws out_of_range if the check fails.
1352 */
1353 reference
1354 at(size_type __n)
1355 {
1356 _M_range_check(__n);
1357 return (*this)[__n];
1358 }
1359
1360 /**
1361 * @brief Provides access to the data contained in the %deque.
1362 * @param __n The index of the element for which data should be
1363 * accessed.
1364 * @return Read-only (constant) reference to data.
1365 * @throw std::out_of_range If @a __n is an invalid index.
1366 *
1367 * This function provides for safer data access. The parameter is first
1368 * checked that it is in the range of the deque. The function throws
1369 * out_of_range if the check fails.
1370 */
1371 const_reference
1372 at(size_type __n) const
1373 {
1374 _M_range_check(__n);
1375 return (*this)[__n];
1376 }
1377
1378 /**
1379 * Returns a read/write reference to the data at the first
1380 * element of the %deque.
1381 */
1382 reference
1383 front() _GLIBCXX_NOEXCEPT
1384 {
1385 __glibcxx_requires_nonempty();
1386 return *begin();
1387 }
1388
1389 /**
1390 * Returns a read-only (constant) reference to the data at the first
1391 * element of the %deque.
1392 */
1393 const_reference
1394 front() const _GLIBCXX_NOEXCEPT
1395 {
1396 __glibcxx_requires_nonempty();
1397 return *begin();
1398 }
1399
1400 /**
1401 * Returns a read/write reference to the data at the last element of the
1402 * %deque.
1403 */
1404 reference
1405 back() _GLIBCXX_NOEXCEPT
1406 {
1407 __glibcxx_requires_nonempty();
1408 iterator __tmp = end();
1409 --__tmp;
1410 return *__tmp;
1411 }
1412
1413 /**
1414 * Returns a read-only (constant) reference to the data at the last
1415 * element of the %deque.
1416 */
1417 const_reference
1418 back() const _GLIBCXX_NOEXCEPT
1419 {
1420 __glibcxx_requires_nonempty();
1421 const_iterator __tmp = end();
1422 --__tmp;
1423 return *__tmp;
1424 }
1425
1426 // [23.2.1.2] modifiers
1427 /**
1428 * @brief Add data to the front of the %deque.
1429 * @param __x Data to be added.
1430 *
1431 * This is a typical stack operation. The function creates an
1432 * element at the front of the %deque and assigns the given
1433 * data to it. Due to the nature of a %deque this operation
1434 * can be done in constant time.
1435 */
1436 void
1437 push_front(const value_type& __x)
1438 {
1439 if (this->_M_impl._M_start._M_cur != this->_M_impl._M_start._M_first)
1440 {
1441 _Alloc_traits::construct(this->_M_impl,
1442 this->_M_impl._M_start._M_cur - 1,
1443 __x);
1444 --this->_M_impl._M_start._M_cur;
1445 }
1446 else
1447 _M_push_front_aux(__x);
1448 }
1449
1450#if __cplusplus >= 201103L
1451 void
1452 push_front(value_type&& __x)
1453 { emplace_front(std::move(__x)); }
1454
1455 template<typename... _Args>
1456#if __cplusplus > 201402L
1457 reference
1458#else
1459 void
1460#endif
1461 emplace_front(_Args&&... __args);
1462#endif
1463
1464 /**
1465 * @brief Add data to the end of the %deque.
1466 * @param __x Data to be added.
1467 *
1468 * This is a typical stack operation. The function creates an
1469 * element at the end of the %deque and assigns the given data
1470 * to it. Due to the nature of a %deque this operation can be
1471 * done in constant time.
1472 */
1473 void
1474 push_back(const value_type& __x)
1475 {
1476 if (this->_M_impl._M_finish._M_cur
1477 != this->_M_impl._M_finish._M_last - 1)
1478 {
1479 _Alloc_traits::construct(this->_M_impl,
1480 this->_M_impl._M_finish._M_cur, __x);
1481 ++this->_M_impl._M_finish._M_cur;
1482 }
1483 else
1484 _M_push_back_aux(__x);
1485 }
1486
1487#if __cplusplus >= 201103L
1488 void
1489 push_back(value_type&& __x)
1490 { emplace_back(std::move(__x)); }
1491
1492 template<typename... _Args>
1493#if __cplusplus > 201402L
1494 reference
1495#else
1496 void
1497#endif
1498 emplace_back(_Args&&... __args);
1499#endif
1500
1501 /**
1502 * @brief Removes first element.
1503 *
1504 * This is a typical stack operation. It shrinks the %deque by one.
1505 *
1506 * Note that no data is returned, and if the first element's data is
1507 * needed, it should be retrieved before pop_front() is called.
1508 */
1509 void
1510 pop_front() _GLIBCXX_NOEXCEPT
1511 {
1512 __glibcxx_requires_nonempty();
1513 if (this->_M_impl._M_start._M_cur
1514 != this->_M_impl._M_start._M_last - 1)
1515 {
1516 _Alloc_traits::destroy(_M_get_Tp_allocator(),
1517 this->_M_impl._M_start._M_cur);
1518 ++this->_M_impl._M_start._M_cur;
1519 }
1520 else
1521 _M_pop_front_aux();
1522 }
1523
1524 /**
1525 * @brief Removes last element.
1526 *
1527 * This is a typical stack operation. It shrinks the %deque by one.
1528 *
1529 * Note that no data is returned, and if the last element's data is
1530 * needed, it should be retrieved before pop_back() is called.
1531 */
1532 void
1533 pop_back() _GLIBCXX_NOEXCEPT
1534 {
1535 __glibcxx_requires_nonempty();
1536 if (this->_M_impl._M_finish._M_cur
1537 != this->_M_impl._M_finish._M_first)
1538 {
1539 --this->_M_impl._M_finish._M_cur;
1540 _Alloc_traits::destroy(_M_get_Tp_allocator(),
1541 this->_M_impl._M_finish._M_cur);
1542 }
1543 else
1544 _M_pop_back_aux();
1545 }
1546
1547#if __cplusplus >= 201103L
1548 /**
1549 * @brief Inserts an object in %deque before specified iterator.
1550 * @param __position A const_iterator into the %deque.
1551 * @param __args Arguments.
1552 * @return An iterator that points to the inserted data.
1553 *
1554 * This function will insert an object of type T constructed
1555 * with T(std::forward<Args>(args)...) before the specified location.
1556 */
1557 template<typename... _Args>
1558 iterator
1559 emplace(const_iterator __position, _Args&&... __args);
1560
1561 /**
1562 * @brief Inserts given value into %deque before specified iterator.
1563 * @param __position A const_iterator into the %deque.
1564 * @param __x Data to be inserted.
1565 * @return An iterator that points to the inserted data.
1566 *
1567 * This function will insert a copy of the given value before the
1568 * specified location.
1569 */
1570 iterator
1571 insert(const_iterator __position, const value_type& __x);
1572#else
1573 /**
1574 * @brief Inserts given value into %deque before specified iterator.
1575 * @param __position An iterator into the %deque.
1576 * @param __x Data to be inserted.
1577 * @return An iterator that points to the inserted data.
1578 *
1579 * This function will insert a copy of the given value before the
1580 * specified location.
1581 */
1582 iterator
1583 insert(iterator __position, const value_type& __x);
1584#endif
1585
1586#if __cplusplus >= 201103L
1587 /**
1588 * @brief Inserts given rvalue into %deque before specified iterator.
1589 * @param __position A const_iterator into the %deque.
1590 * @param __x Data to be inserted.
1591 * @return An iterator that points to the inserted data.
1592 *
1593 * This function will insert a copy of the given rvalue before the
1594 * specified location.
1595 */
1596 iterator
1597 insert(const_iterator __position, value_type&& __x)
1598 { return emplace(__position, std::move(__x)); }
1599
1600 /**
1601 * @brief Inserts an initializer list into the %deque.
1602 * @param __p An iterator into the %deque.
1603 * @param __l An initializer_list.
1604 * @return An iterator that points to the inserted data.
1605 *
1606 * This function will insert copies of the data in the
1607 * initializer_list @a __l into the %deque before the location
1608 * specified by @a __p. This is known as <em>list insert</em>.
1609 */
1610 iterator
1612 {
1613 auto __offset = __p - cbegin();
1614 _M_range_insert_aux(__p._M_const_cast(), __l.begin(), __l.end(),
1616 return begin() + __offset;
1617 }
1618
1619 /**
1620 * @brief Inserts a number of copies of given data into the %deque.
1621 * @param __position A const_iterator into the %deque.
1622 * @param __n Number of elements to be inserted.
1623 * @param __x Data to be inserted.
1624 * @return An iterator that points to the inserted data.
1625 *
1626 * This function will insert a specified number of copies of the given
1627 * data before the location specified by @a __position.
1628 */
1629 iterator
1630 insert(const_iterator __position, size_type __n, const value_type& __x)
1631 {
1632 difference_type __offset = __position - cbegin();
1633 _M_fill_insert(__position._M_const_cast(), __n, __x);
1634 return begin() + __offset;
1635 }
1636#else
1637 /**
1638 * @brief Inserts a number of copies of given data into the %deque.
1639 * @param __position An iterator into the %deque.
1640 * @param __n Number of elements to be inserted.
1641 * @param __x Data to be inserted.
1642 *
1643 * This function will insert a specified number of copies of the given
1644 * data before the location specified by @a __position.
1645 */
1646 void
1647 insert(iterator __position, size_type __n, const value_type& __x)
1648 { _M_fill_insert(__position, __n, __x); }
1649#endif
1650
1651#if __cplusplus >= 201103L
1652 /**
1653 * @brief Inserts a range into the %deque.
1654 * @param __position A const_iterator into the %deque.
1655 * @param __first An input iterator.
1656 * @param __last An input iterator.
1657 * @return An iterator that points to the inserted data.
1658 *
1659 * This function will insert copies of the data in the range
1660 * [__first,__last) into the %deque before the location specified
1661 * by @a __position. This is known as <em>range insert</em>.
1662 */
1663 template<typename _InputIterator,
1664 typename = std::_RequireInputIter<_InputIterator>>
1665 iterator
1666 insert(const_iterator __position, _InputIterator __first,
1667 _InputIterator __last)
1668 {
1669 difference_type __offset = __position - cbegin();
1670 _M_range_insert_aux(__position._M_const_cast(), __first, __last,
1671 std::__iterator_category(__first));
1672 return begin() + __offset;
1673 }
1674#else
1675 /**
1676 * @brief Inserts a range into the %deque.
1677 * @param __position An iterator into the %deque.
1678 * @param __first An input iterator.
1679 * @param __last An input iterator.
1680 *
1681 * This function will insert copies of the data in the range
1682 * [__first,__last) into the %deque before the location specified
1683 * by @a __position. This is known as <em>range insert</em>.
1684 */
1685 template<typename _InputIterator>
1686 void
1687 insert(iterator __position, _InputIterator __first,
1688 _InputIterator __last)
1689 {
1690 // Check whether it's an integral type. If so, it's not an iterator.
1691 typedef typename std::__is_integer<_InputIterator>::__type _Integral;
1692 _M_insert_dispatch(__position, __first, __last, _Integral());
1693 }
1694#endif
1695
1696 /**
1697 * @brief Remove element at given position.
1698 * @param __position Iterator pointing to element to be erased.
1699 * @return An iterator pointing to the next element (or end()).
1700 *
1701 * This function will erase the element at the given position and thus
1702 * shorten the %deque by one.
1703 *
1704 * The user is cautioned that
1705 * this function only erases the element, and that if the element is
1706 * itself a pointer, the pointed-to memory is not touched in any way.
1707 * Managing the pointer is the user's responsibility.
1708 */
1709 iterator
1710#if __cplusplus >= 201103L
1712#else
1713 erase(iterator __position)
1714#endif
1715 { return _M_erase(__position._M_const_cast()); }
1716
1717 /**
1718 * @brief Remove a range of elements.
1719 * @param __first Iterator pointing to the first element to be erased.
1720 * @param __last Iterator pointing to one past the last element to be
1721 * erased.
1722 * @return An iterator pointing to the element pointed to by @a last
1723 * prior to erasing (or end()).
1724 *
1725 * This function will erase the elements in the range
1726 * [__first,__last) and shorten the %deque accordingly.
1727 *
1728 * The user is cautioned that
1729 * this function only erases the elements, and that if the elements
1730 * themselves are pointers, the pointed-to memory is not touched in any
1731 * way. Managing the pointer is the user's responsibility.
1732 */
1733 iterator
1734#if __cplusplus >= 201103L
1736#else
1737 erase(iterator __first, iterator __last)
1738#endif
1739 { return _M_erase(__first._M_const_cast(), __last._M_const_cast()); }
1740
1741 /**
1742 * @brief Swaps data with another %deque.
1743 * @param __x A %deque of the same element and allocator types.
1744 *
1745 * This exchanges the elements between two deques in constant time.
1746 * (Four pointers, so it should be quite fast.)
1747 * Note that the global std::swap() function is specialized such that
1748 * std::swap(d1,d2) will feed to this function.
1749 *
1750 * Whether the allocators are swapped depends on the allocator traits.
1751 */
1752 void
1753 swap(deque& __x) _GLIBCXX_NOEXCEPT
1754 {
1755#if __cplusplus >= 201103L
1756 __glibcxx_assert(_Alloc_traits::propagate_on_container_swap::value
1757 || _M_get_Tp_allocator() == __x._M_get_Tp_allocator());
1758#endif
1759 _M_impl._M_swap_data(__x._M_impl);
1760 _Alloc_traits::_S_on_swap(_M_get_Tp_allocator(),
1761 __x._M_get_Tp_allocator());
1762 }
1763
1764 /**
1765 * Erases all the elements. Note that this function only erases the
1766 * elements, and that if the elements themselves are pointers, the
1767 * pointed-to memory is not touched in any way. Managing the pointer is
1768 * the user's responsibility.
1769 */
1770 void
1771 clear() _GLIBCXX_NOEXCEPT
1772 { _M_erase_at_end(begin()); }
1773
1774 protected:
1775 // Internal constructor functions follow.
1776
1777#if __cplusplus < 201103L
1778 // called by the range constructor to implement [23.1.1]/9
1779
1780 // _GLIBCXX_RESOLVE_LIB_DEFECTS
1781 // 438. Ambiguity in the "do the right thing" clause
1782 template<typename _Integer>
1783 void
1784 _M_initialize_dispatch(_Integer __n, _Integer __x, __true_type)
1785 {
1786 _M_initialize_map(_S_check_init_len(static_cast<size_type>(__n),
1787 _M_get_Tp_allocator()));
1788 _M_fill_initialize(__x);
1789 }
1790
1791 // called by the range constructor to implement [23.1.1]/9
1792 template<typename _InputIterator>
1793 void
1794 _M_initialize_dispatch(_InputIterator __first, _InputIterator __last,
1795 __false_type)
1796 {
1797 _M_range_initialize(__first, __last,
1798 std::__iterator_category(__first));
1799 }
1800#endif
1801
1802 static size_t
1803 _S_check_init_len(size_t __n, const allocator_type& __a)
1804 {
1805 if (__n > _S_max_size(__a))
1806 __throw_length_error(
1807 __N("cannot create std::deque larger than max_size()"));
1808 return __n;
1809 }
1810
1811 static size_type
1812 _S_max_size(const _Tp_alloc_type& __a) _GLIBCXX_NOEXCEPT
1813 {
1814 const size_t __diffmax = __gnu_cxx::__numeric_traits<ptrdiff_t>::__max;
1815 const size_t __allocmax = _Alloc_traits::max_size(__a);
1816 return (std::min)(__diffmax, __allocmax);
1817 }
1818
1819 // called by the second initialize_dispatch above
1820 //@{
1821 /**
1822 * @brief Fills the deque with whatever is in [first,last).
1823 * @param __first An input iterator.
1824 * @param __last An input iterator.
1825 * @return Nothing.
1826 *
1827 * If the iterators are actually forward iterators (or better), then the
1828 * memory layout can be done all at once. Else we move forward using
1829 * push_back on each value from the iterator.
1830 */
1831 template<typename _InputIterator>
1832 void
1833 _M_range_initialize(_InputIterator __first, _InputIterator __last,
1835
1836 // called by the second initialize_dispatch above
1837 template<typename _ForwardIterator>
1838 void
1839 _M_range_initialize(_ForwardIterator __first, _ForwardIterator __last,
1841 //@}
1842
1843 /**
1844 * @brief Fills the %deque with copies of value.
1845 * @param __value Initial value.
1846 * @return Nothing.
1847 * @pre _M_start and _M_finish have already been initialized,
1848 * but none of the %deque's elements have yet been constructed.
1849 *
1850 * This function is called only when the user provides an explicit size
1851 * (with or without an explicit exemplar value).
1852 */
1853 void
1854 _M_fill_initialize(const value_type& __value);
1855
1856#if __cplusplus >= 201103L
1857 // called by deque(n).
1858 void
1859 _M_default_initialize();
1860#endif
1861
1862 // Internal assign functions follow. The *_aux functions do the actual
1863 // assignment work for the range versions.
1864
1865#if __cplusplus < 201103L
1866 // called by the range assign to implement [23.1.1]/9
1867
1868 // _GLIBCXX_RESOLVE_LIB_DEFECTS
1869 // 438. Ambiguity in the "do the right thing" clause
1870 template<typename _Integer>
1871 void
1872 _M_assign_dispatch(_Integer __n, _Integer __val, __true_type)
1873 { _M_fill_assign(__n, __val); }
1874
1875 // called by the range assign to implement [23.1.1]/9
1876 template<typename _InputIterator>
1877 void
1878 _M_assign_dispatch(_InputIterator __first, _InputIterator __last,
1879 __false_type)
1880 { _M_assign_aux(__first, __last, std::__iterator_category(__first)); }
1881#endif
1882
1883 // called by the second assign_dispatch above
1884 template<typename _InputIterator>
1885 void
1886 _M_assign_aux(_InputIterator __first, _InputIterator __last,
1888
1889 // called by the second assign_dispatch above
1890 template<typename _ForwardIterator>
1891 void
1892 _M_assign_aux(_ForwardIterator __first, _ForwardIterator __last,
1894 {
1895 const size_type __len = std::distance(__first, __last);
1896 if (__len > size())
1897 {
1898 _ForwardIterator __mid = __first;
1899 std::advance(__mid, size());
1900 std::copy(__first, __mid, begin());
1901 _M_range_insert_aux(end(), __mid, __last,
1902 std::__iterator_category(__first));
1903 }
1904 else
1905 _M_erase_at_end(std::copy(__first, __last, begin()));
1906 }
1907
1908 // Called by assign(n,t), and the range assign when it turns out
1909 // to be the same thing.
1910 void
1911 _M_fill_assign(size_type __n, const value_type& __val)
1912 {
1913 if (__n > size())
1914 {
1915 std::fill(begin(), end(), __val);
1916 _M_fill_insert(end(), __n - size(), __val);
1917 }
1918 else
1919 {
1920 _M_erase_at_end(begin() + difference_type(__n));
1921 std::fill(begin(), end(), __val);
1922 }
1923 }
1924
1925 //@{
1926 /// Helper functions for push_* and pop_*.
1927#if __cplusplus < 201103L
1928 void _M_push_back_aux(const value_type&);
1929
1930 void _M_push_front_aux(const value_type&);
1931#else
1932 template<typename... _Args>
1933 void _M_push_back_aux(_Args&&... __args);
1934
1935 template<typename... _Args>
1936 void _M_push_front_aux(_Args&&... __args);
1937#endif
1938
1939 void _M_pop_back_aux();
1940
1941 void _M_pop_front_aux();
1942 //@}
1943
1944 // Internal insert functions follow. The *_aux functions do the actual
1945 // insertion work when all shortcuts fail.
1946
1947#if __cplusplus < 201103L
1948 // called by the range insert to implement [23.1.1]/9
1949
1950 // _GLIBCXX_RESOLVE_LIB_DEFECTS
1951 // 438. Ambiguity in the "do the right thing" clause
1952 template<typename _Integer>
1953 void
1954 _M_insert_dispatch(iterator __pos,
1955 _Integer __n, _Integer __x, __true_type)
1956 { _M_fill_insert(__pos, __n, __x); }
1957
1958 // called by the range insert to implement [23.1.1]/9
1959 template<typename _InputIterator>
1960 void
1961 _M_insert_dispatch(iterator __pos,
1962 _InputIterator __first, _InputIterator __last,
1963 __false_type)
1964 {
1965 _M_range_insert_aux(__pos, __first, __last,
1966 std::__iterator_category(__first));
1967 }
1968#endif
1969
1970 // called by the second insert_dispatch above
1971 template<typename _InputIterator>
1972 void
1973 _M_range_insert_aux(iterator __pos, _InputIterator __first,
1974 _InputIterator __last, std::input_iterator_tag);
1975
1976 // called by the second insert_dispatch above
1977 template<typename _ForwardIterator>
1978 void
1979 _M_range_insert_aux(iterator __pos, _ForwardIterator __first,
1980 _ForwardIterator __last, std::forward_iterator_tag);
1981
1982 // Called by insert(p,n,x), and the range insert when it turns out to be
1983 // the same thing. Can use fill functions in optimal situations,
1984 // otherwise passes off to insert_aux(p,n,x).
1985 void
1986 _M_fill_insert(iterator __pos, size_type __n, const value_type& __x);
1987
1988 // called by insert(p,x)
1989#if __cplusplus < 201103L
1990 iterator
1991 _M_insert_aux(iterator __pos, const value_type& __x);
1992#else
1993 template<typename... _Args>
1994 iterator
1995 _M_insert_aux(iterator __pos, _Args&&... __args);
1996#endif
1997
1998 // called by insert(p,n,x) via fill_insert
1999 void
2000 _M_insert_aux(iterator __pos, size_type __n, const value_type& __x);
2001
2002 // called by range_insert_aux for forward iterators
2003 template<typename _ForwardIterator>
2004 void
2005 _M_insert_aux(iterator __pos,
2006 _ForwardIterator __first, _ForwardIterator __last,
2007 size_type __n);
2008
2009
2010 // Internal erase functions follow.
2011
2012 void
2013 _M_destroy_data_aux(iterator __first, iterator __last);
2014
2015 // Called by ~deque().
2016 // NB: Doesn't deallocate the nodes.
2017 template<typename _Alloc1>
2018 void
2019 _M_destroy_data(iterator __first, iterator __last, const _Alloc1&)
2020 { _M_destroy_data_aux(__first, __last); }
2021
2022 void
2023 _M_destroy_data(iterator __first, iterator __last,
2024 const std::allocator<_Tp>&)
2025 {
2026 if (!__has_trivial_destructor(value_type))
2027 _M_destroy_data_aux(__first, __last);
2028 }
2029
2030 // Called by erase(q1, q2).
2031 void
2032 _M_erase_at_begin(iterator __pos)
2033 {
2034 _M_destroy_data(begin(), __pos, _M_get_Tp_allocator());
2035 _M_destroy_nodes(this->_M_impl._M_start._M_node, __pos._M_node);
2036 this->_M_impl._M_start = __pos;
2037 }
2038
2039 // Called by erase(q1, q2), resize(), clear(), _M_assign_aux,
2040 // _M_fill_assign, operator=.
2041 void
2042 _M_erase_at_end(iterator __pos)
2043 {
2044 _M_destroy_data(__pos, end(), _M_get_Tp_allocator());
2045 _M_destroy_nodes(__pos._M_node + 1,
2046 this->_M_impl._M_finish._M_node + 1);
2047 this->_M_impl._M_finish = __pos;
2048 }
2049
2050 iterator
2051 _M_erase(iterator __pos);
2052
2053 iterator
2054 _M_erase(iterator __first, iterator __last);
2055
2056#if __cplusplus >= 201103L
2057 // Called by resize(sz).
2058 void
2059 _M_default_append(size_type __n);
2060
2061 bool
2062 _M_shrink_to_fit();
2063#endif
2064
2065 //@{
2066 /// Memory-handling helpers for the previous internal insert functions.
2067 iterator
2069 {
2070 const size_type __vacancies = this->_M_impl._M_start._M_cur
2071 - this->_M_impl._M_start._M_first;
2072 if (__n > __vacancies)
2073 _M_new_elements_at_front(__n - __vacancies);
2074 return this->_M_impl._M_start - difference_type(__n);
2075 }
2076
2077 iterator
2078 _M_reserve_elements_at_back(size_type __n)
2079 {
2080 const size_type __vacancies = (this->_M_impl._M_finish._M_last
2081 - this->_M_impl._M_finish._M_cur) - 1;
2082 if (__n > __vacancies)
2083 _M_new_elements_at_back(__n - __vacancies);
2084 return this->_M_impl._M_finish + difference_type(__n);
2085 }
2086
2087 void
2088 _M_new_elements_at_front(size_type __new_elements);
2089
2090 void
2091 _M_new_elements_at_back(size_type __new_elements);
2092 //@}
2093
2094
2095 //@{
2096 /**
2097 * @brief Memory-handling helpers for the major %map.
2098 *
2099 * Makes sure the _M_map has space for new nodes. Does not
2100 * actually add the nodes. Can invalidate _M_map pointers.
2101 * (And consequently, %deque iterators.)
2102 */
2103 void
2104 _M_reserve_map_at_back(size_type __nodes_to_add = 1)
2105 {
2106 if (__nodes_to_add + 1 > this->_M_impl._M_map_size
2107 - (this->_M_impl._M_finish._M_node - this->_M_impl._M_map))
2108 _M_reallocate_map(__nodes_to_add, false);
2109 }
2110
2111 void
2112 _M_reserve_map_at_front(size_type __nodes_to_add = 1)
2113 {
2114 if (__nodes_to_add > size_type(this->_M_impl._M_start._M_node
2115 - this->_M_impl._M_map))
2116 _M_reallocate_map(__nodes_to_add, true);
2117 }
2118
2119 void
2120 _M_reallocate_map(size_type __nodes_to_add, bool __add_at_front);
2121 //@}
2122
2123#if __cplusplus >= 201103L
2124 // Constant-time, nothrow move assignment when source object's memory
2125 // can be moved because the allocators are equal.
2126 void
2127 _M_move_assign1(deque&& __x, /* always equal: */ true_type) noexcept
2128 {
2129 this->_M_impl._M_swap_data(__x._M_impl);
2130 __x.clear();
2131 std::__alloc_on_move(_M_get_Tp_allocator(), __x._M_get_Tp_allocator());
2132 }
2133
2134 // When the allocators are not equal the operation could throw, because
2135 // we might need to allocate a new map for __x after moving from it
2136 // or we might need to allocate new elements for *this.
2137 void
2138 _M_move_assign1(deque&& __x, /* always equal: */ false_type)
2139 {
2140 constexpr bool __move_storage =
2141 _Alloc_traits::_S_propagate_on_move_assign();
2142 _M_move_assign2(std::move(__x), __bool_constant<__move_storage>());
2143 }
2144
2145 // Destroy all elements and deallocate all memory, then replace
2146 // with elements created from __args.
2147 template<typename... _Args>
2148 void
2149 _M_replace_map(_Args&&... __args)
2150 {
2151 // Create new data first, so if allocation fails there are no effects.
2152 deque __newobj(std::forward<_Args>(__args)...);
2153 // Free existing storage using existing allocator.
2154 clear();
2155 _M_deallocate_node(*begin()._M_node); // one node left after clear()
2156 _M_deallocate_map(this->_M_impl._M_map, this->_M_impl._M_map_size);
2157 this->_M_impl._M_map = nullptr;
2158 this->_M_impl._M_map_size = 0;
2159 // Take ownership of replacement memory.
2160 this->_M_impl._M_swap_data(__newobj._M_impl);
2161 }
2162
2163 // Do move assignment when the allocator propagates.
2164 void
2165 _M_move_assign2(deque&& __x, /* propagate: */ true_type)
2166 {
2167 // Make a copy of the original allocator state.
2168 auto __alloc = __x._M_get_Tp_allocator();
2169 // The allocator propagates so storage can be moved from __x,
2170 // leaving __x in a valid empty state with a moved-from allocator.
2171 _M_replace_map(std::move(__x));
2172 // Move the corresponding allocator state too.
2173 _M_get_Tp_allocator() = std::move(__alloc);
2174 }
2175
2176 // Do move assignment when it may not be possible to move source
2177 // object's memory, resulting in a linear-time operation.
2178 void
2179 _M_move_assign2(deque&& __x, /* propagate: */ false_type)
2180 {
2181 if (__x._M_get_Tp_allocator() == this->_M_get_Tp_allocator())
2182 {
2183 // The allocators are equal so storage can be moved from __x,
2184 // leaving __x in a valid empty state with its current allocator.
2185 _M_replace_map(std::move(__x), __x.get_allocator());
2186 }
2187 else
2188 {
2189 // The rvalue's allocator cannot be moved and is not equal,
2190 // so we need to individually move each element.
2191 _M_assign_aux(std::make_move_iterator(__x.begin()),
2192 std::make_move_iterator(__x.end()),
2194 __x.clear();
2195 }
2196 }
2197#endif
2198 };
2199
2200#if __cpp_deduction_guides >= 201606
2201 template<typename _InputIterator, typename _ValT
2202 = typename iterator_traits<_InputIterator>::value_type,
2203 typename _Allocator = allocator<_ValT>,
2204 typename = _RequireInputIter<_InputIterator>,
2205 typename = _RequireAllocator<_Allocator>>
2206 deque(_InputIterator, _InputIterator, _Allocator = _Allocator())
2207 -> deque<_ValT, _Allocator>;
2208#endif
2209
2210 /**
2211 * @brief Deque equality comparison.
2212 * @param __x A %deque.
2213 * @param __y A %deque of the same type as @a __x.
2214 * @return True iff the size and elements of the deques are equal.
2215 *
2216 * This is an equivalence relation. It is linear in the size of the
2217 * deques. Deques are considered equivalent if their sizes are equal,
2218 * and if corresponding elements compare equal.
2219 */
2220 template<typename _Tp, typename _Alloc>
2221 inline bool
2222 operator==(const deque<_Tp, _Alloc>& __x, const deque<_Tp, _Alloc>& __y)
2223 { return __x.size() == __y.size()
2224 && std::equal(__x.begin(), __x.end(), __y.begin()); }
2225
2226 /**
2227 * @brief Deque ordering relation.
2228 * @param __x A %deque.
2229 * @param __y A %deque of the same type as @a __x.
2230 * @return True iff @a x is lexicographically less than @a __y.
2231 *
2232 * This is a total ordering relation. It is linear in the size of the
2233 * deques. The elements must be comparable with @c <.
2234 *
2235 * See std::lexicographical_compare() for how the determination is made.
2236 */
2237 template<typename _Tp, typename _Alloc>
2238 inline bool
2239 operator<(const deque<_Tp, _Alloc>& __x, const deque<_Tp, _Alloc>& __y)
2240 { return std::lexicographical_compare(__x.begin(), __x.end(),
2241 __y.begin(), __y.end()); }
2242
2243 /// Based on operator==
2244 template<typename _Tp, typename _Alloc>
2245 inline bool
2246 operator!=(const deque<_Tp, _Alloc>& __x, const deque<_Tp, _Alloc>& __y)
2247 { return !(__x == __y); }
2248
2249 /// Based on operator<
2250 template<typename _Tp, typename _Alloc>
2251 inline bool
2252 operator>(const deque<_Tp, _Alloc>& __x, const deque<_Tp, _Alloc>& __y)
2253 { return __y < __x; }
2254
2255 /// Based on operator<
2256 template<typename _Tp, typename _Alloc>
2257 inline bool
2258 operator<=(const deque<_Tp, _Alloc>& __x, const deque<_Tp, _Alloc>& __y)
2259 { return !(__y < __x); }
2260
2261 /// Based on operator<
2262 template<typename _Tp, typename _Alloc>
2263 inline bool
2264 operator>=(const deque<_Tp, _Alloc>& __x, const deque<_Tp, _Alloc>& __y)
2265 { return !(__x < __y); }
2266
2267 /// See std::deque::swap().
2268 template<typename _Tp, typename _Alloc>
2269 inline void
2271 _GLIBCXX_NOEXCEPT_IF(noexcept(__x.swap(__y)))
2272 { __x.swap(__y); }
2273
2274#undef _GLIBCXX_DEQUE_BUF_SIZE
2275
2276_GLIBCXX_END_NAMESPACE_CONTAINER
2277
2278#if __cplusplus >= 201103L
2279 // std::allocator is safe, but it is not the only allocator
2280 // for which this is valid.
2281 template<class _Tp>
2282 struct __is_bitwise_relocatable<_GLIBCXX_STD_C::deque<_Tp>>
2283 : true_type { };
2284#endif
2285
2286_GLIBCXX_END_NAMESPACE_VERSION
2287} // namespace std
2288
2289#endif /* _STL_DEQUE_H */
#define _GLIBCXX_DEQUE_BUF_SIZE
This function controls the size of memory nodes.
Definition: stl_deque.h:89
integral_constant< bool, true > true_type
The type used as a compile-time boolean with true value.
Definition: type_traits:75
integral_constant< bool, false > false_type
The type used as a compile-time boolean with false value.
Definition: type_traits:78
constexpr std::remove_reference< _Tp >::type && move(_Tp &&__t) noexcept
Convert a value to an rvalue.
Definition: move.h:101
constexpr const _Tp & max(const _Tp &, const _Tp &)
This does what you think it does.
Definition: stl_algobase.h:254
constexpr const _Tp & min(const _Tp &, const _Tp &)
This does what you think it does.
Definition: stl_algobase.h:230
ISO C++ entities toplevel namespace is std.
typename pointer_traits< _Ptr >::template rebind< _Tp > __ptr_rebind
Convenience alias for rebinding pointers.
Definition: ptr_traits.h:151
constexpr iterator_traits< _Iter >::iterator_category __iterator_category(const _Iter &)
constexpr iterator_traits< _InputIterator >::difference_type distance(_InputIterator __first, _InputIterator __last)
A generalization of pointer arithmetic.
constexpr void advance(_InputIterator &__i, _Distance __n)
A generalization of pointer arithmetic.
initializer_list
integral_constant
Definition: type_traits:58
is_same
Definition: type_traits:1388
is_nothrow_default_constructible
Definition: type_traits:1007
__detected_or_t< typename is_empty< _Tp_alloc_type >::type, __equal, _Tp_alloc_type > is_always_equal
Whether all instances of the allocator type compare equal.
The standard allocator, as per [20.4].
Definition: allocator.h:121
A deque::iterator.
Definition: stl_deque.h:111
void _M_set_node(_Map_pointer __new_node) noexcept
Definition: stl_deque.h:257
void _M_initialize_map(size_t)
Layout storage.
Definition: stl_deque.h:596
A standard container using fixed-size memory allocation and constant-time manipulation of elements at...
Definition: stl_deque.h:746
reverse_iterator rbegin() noexcept
Definition: stl_deque.h:1141
deque(const deque &__x)
Deque copy constructor.
Definition: stl_deque.h:874
const_reference at(size_type __n) const
Provides access to the data contained in the deque.
Definition: stl_deque.h:1372
deque(const deque &__x, const allocator_type &__a)
Copy constructor with alternative allocator.
Definition: stl_deque.h:893
deque(deque &&__x, const allocator_type &__a)
Move constructor with alternative allocator.
Definition: stl_deque.h:900
reverse_iterator rend() noexcept
Definition: stl_deque.h:1159
iterator erase(const_iterator __position)
Remove element at given position.
Definition: stl_deque.h:1711
const_reference back() const noexcept
Definition: stl_deque.h:1418
const_reverse_iterator crend() const noexcept
Definition: stl_deque.h:1204
void clear() noexcept
Definition: stl_deque.h:1771
void pop_back() noexcept
Removes last element.
Definition: stl_deque.h:1533
size_type size() const noexcept
Definition: stl_deque.h:1211
const_iterator cbegin() const noexcept
Definition: stl_deque.h:1177
void resize(size_type __new_size)
Resizes the deque to the specified number of elements.
Definition: stl_deque.h:1230
const_reverse_iterator rend() const noexcept
Definition: stl_deque.h:1168
iterator _M_reserve_elements_at_front(size_type __n)
Memory-handling helpers for the previous internal insert functions.
Definition: stl_deque.h:2068
iterator emplace(const_iterator __position, _Args &&... __args)
Inserts an object in deque before specified iterator.
Definition: deque.tcc:188
void pop_front() noexcept
Removes first element.
Definition: stl_deque.h:1510
allocator_type get_allocator() const noexcept
Get a copy of the memory allocation object.
Definition: stl_deque.h:1097
void swap(deque &__x) noexcept
Swaps data with another deque.
Definition: stl_deque.h:1753
reference operator[](size_type __n) noexcept
Subscript access to the data contained in the deque.
Definition: stl_deque.h:1305
reference at(size_type __n)
Provides access to the data contained in the deque.
Definition: stl_deque.h:1354
deque(size_type __n, const allocator_type &__a=allocator_type())
Creates a deque with default constructed elements.
Definition: stl_deque.h:835
bool empty() const noexcept
Definition: stl_deque.h:1289
const_reference operator[](size_type __n) const noexcept
Subscript access to the data contained in the deque.
Definition: stl_deque.h:1323
size_type max_size() const noexcept
Definition: stl_deque.h:1216
void push_front(const value_type &__x)
Add data to the front of the deque.
Definition: stl_deque.h:1437
void resize(size_type __new_size, const value_type &__x)
Resizes the deque to the specified number of elements.
Definition: stl_deque.h:1252
const_reference front() const noexcept
Definition: stl_deque.h:1394
void assign(size_type __n, const value_type &__val)
Assigns a given value to a deque.
Definition: stl_deque.h:1047
deque & operator=(initializer_list< value_type > __l)
Assigns an initializer list to a deque.
Definition: stl_deque.h:1028
void _M_fill_initialize(const value_type &__value)
Fills the deque with copies of value.
Definition: deque.tcc:394
iterator insert(const_iterator __position, const value_type &__x)
Inserts given value into deque before specified iterator.
Definition: deque.tcc:212
iterator insert(const_iterator __p, initializer_list< value_type > __l)
Inserts an initializer list into the deque.
Definition: stl_deque.h:1611
iterator end() noexcept
Definition: stl_deque.h:1123
deque(size_type __n, const value_type &__value, const allocator_type &__a=allocator_type())
Creates a deque with copies of an exemplar element.
Definition: stl_deque.h:847
const_reverse_iterator crbegin() const noexcept
Definition: stl_deque.h:1195
void _M_reserve_map_at_back(size_type __nodes_to_add=1)
Memory-handling helpers for the major map.
Definition: stl_deque.h:2104
reference back() noexcept
Definition: stl_deque.h:1405
deque()=default
Creates a deque with no elements.
void _M_push_back_aux(_Args &&... __args)
Helper functions for push_* and pop_*.
Definition: deque.tcc:482
deque & operator=(deque &&__x) noexcept(_Alloc_traits::_S_always_equal())
Deque move assignment operator.
Definition: stl_deque.h:1009
void push_back(const value_type &__x)
Add data to the end of the deque.
Definition: stl_deque.h:1474
deque(const allocator_type &__a)
Creates a deque with no elements.
Definition: stl_deque.h:822
void _M_range_check(size_type __n) const
Safety check used only from at().
Definition: stl_deque.h:1332
void assign(initializer_list< value_type > __l)
Assigns an initializer list to a deque.
Definition: stl_deque.h:1091
deque(initializer_list< value_type > __l, const allocator_type &__a=allocator_type())
Builds a deque from an initializer list.
Definition: stl_deque.h:933
void shrink_to_fit() noexcept
Definition: stl_deque.h:1280
void assign(_InputIterator __first, _InputIterator __last)
Assigns a range to a deque.
Definition: stl_deque.h:1066
deque(_InputIterator __first, _InputIterator __last, const allocator_type &__a=allocator_type())
Builds a deque from a range.
Definition: stl_deque.h:960
const_iterator begin() const noexcept
Definition: stl_deque.h:1114
deque & operator=(const deque &__x)
Deque assignment operator.
Definition: deque.tcc:96
const_iterator end() const noexcept
Definition: stl_deque.h:1132
iterator insert(const_iterator __position, size_type __n, const value_type &__x)
Inserts a number of copies of given data into the deque.
Definition: stl_deque.h:1630
iterator insert(const_iterator __position, value_type &&__x)
Inserts given rvalue into deque before specified iterator.
Definition: stl_deque.h:1597
void _M_range_initialize(_InputIterator __first, _InputIterator __last, std::input_iterator_tag)
Fills the deque with whatever is in [first,last).
Definition: deque.tcc:420
reference front() noexcept
Definition: stl_deque.h:1383
const_iterator cend() const noexcept
Definition: stl_deque.h:1186
iterator insert(const_iterator __position, _InputIterator __first, _InputIterator __last)
Inserts a range into the deque.
Definition: stl_deque.h:1666
const_reverse_iterator rbegin() const noexcept
Definition: stl_deque.h:1150
iterator begin() noexcept
Definition: stl_deque.h:1106
iterator erase(const_iterator __first, const_iterator __last)
Remove a range of elements.
Definition: stl_deque.h:1735
deque(deque &&)=default
Deque move constructor.
Marking input iterators.
Forward iterators support a superset of input iterator operations.
Random-access iterators support a superset of bidirectional iterator operations.
Common iterator class.
Uniform interface to C++98 and C++11 allocators.
static constexpr pointer allocate(_Alloc &__a, size_type __n)
Allocate memory.
static constexpr void deallocate(_Alloc &__a, pointer __p, size_type __n)
Deallocate memory.
static constexpr size_type max_size(const _Tp_alloc_type &__a) noexcept
The maximum supported allocation size.