1 // Deque implementation -*- C++ -*-
3 // Copyright (C) 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
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
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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.
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18 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
21 // As a special exception, you may use this file as part of a free software
22 // library without restriction. Specifically, if other files instantiate
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25 // file does not by itself cause the resulting executable to be covered by
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45 * Silicon Graphics Computer Systems, Inc.
47 * Permission to use, copy, modify, distribute and sell this software
48 * and its documentation for any purpose is hereby granted without fee,
49 * provided that the above copyright notice appear in all copies and
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57 * This is an internal header file, included by other library headers.
58 * You should not attempt to use it directly.
64 #include <bits/concept_check.h>
65 #include <bits/stl_iterator_base_types.h>
66 #include <bits/stl_iterator_base_funcs.h>
68 namespace _GLIBCXX_STD
72 * @brief This function controls the size of memory nodes.
73 * @param size The size of an element.
74 * @return The number (not byte size) of elements per node.
76 * This function started off as a compiler kludge from SGI, but seems to
77 * be a useful wrapper around a repeated constant expression. The '512' is
78 * tuneable (and no other code needs to change), but no investigation has
79 * been done since inheriting the SGI code.
83 __deque_buf_size(size_t __size)
84 { return __size < 512 ? size_t(512 / __size) : size_t(1); }
88 * @brief A deque::iterator.
90 * Quite a bit of intelligence here. Much of the functionality of
91 * deque is actually passed off to this class. A deque holds two
92 * of these internally, marking its valid range. Access to
93 * elements is done as offsets of either of those two, relying on
94 * operator overloading in this class.
97 * All the functions are op overloads except for _M_set_node.
100 template<typename _Tp, typename _Ref, typename _Ptr>
101 struct _Deque_iterator
103 typedef _Deque_iterator<_Tp, _Tp&, _Tp*> iterator;
104 typedef _Deque_iterator<_Tp, const _Tp&, const _Tp*> const_iterator;
106 static size_t _S_buffer_size()
107 { return __deque_buf_size(sizeof(_Tp)); }
109 typedef std::random_access_iterator_tag iterator_category;
110 typedef _Tp value_type;
111 typedef _Ptr pointer;
112 typedef _Ref reference;
113 typedef size_t size_type;
114 typedef ptrdiff_t difference_type;
115 typedef _Tp** _Map_pointer;
116 typedef _Deque_iterator _Self;
121 _Map_pointer _M_node;
123 _Deque_iterator(_Tp* __x, _Map_pointer __y)
124 : _M_cur(__x), _M_first(*__y),
125 _M_last(*__y + _S_buffer_size()), _M_node(__y) {}
127 _Deque_iterator() : _M_cur(0), _M_first(0), _M_last(0), _M_node(0) {}
129 _Deque_iterator(const iterator& __x)
130 : _M_cur(__x._M_cur), _M_first(__x._M_first),
131 _M_last(__x._M_last), _M_node(__x._M_node) {}
145 if (_M_cur == _M_last)
147 _M_set_node(_M_node + 1);
164 if (_M_cur == _M_first)
166 _M_set_node(_M_node - 1);
182 operator+=(difference_type __n)
184 const difference_type __offset = __n + (_M_cur - _M_first);
185 if (__offset >= 0 && __offset < difference_type(_S_buffer_size()))
189 const difference_type __node_offset =
190 __offset > 0 ? __offset / difference_type(_S_buffer_size())
191 : -difference_type((-__offset - 1)
192 / _S_buffer_size()) - 1;
193 _M_set_node(_M_node + __node_offset);
194 _M_cur = _M_first + (__offset - __node_offset
195 * difference_type(_S_buffer_size()));
201 operator+(difference_type __n) const
208 operator-=(difference_type __n)
209 { return *this += -__n; }
212 operator-(difference_type __n) const
219 operator[](difference_type __n) const
220 { return *(*this + __n); }
223 * Prepares to traverse new_node. Sets everything except
224 * _M_cur, which should therefore be set by the caller
225 * immediately afterwards, based on _M_first and _M_last.
229 _M_set_node(_Map_pointer __new_node)
231 _M_node = __new_node;
232 _M_first = *__new_node;
233 _M_last = _M_first + difference_type(_S_buffer_size());
237 // Note: we also provide overloads whose operands are of the same type in
238 // order to avoid ambiguous overload resolution when std::rel_ops operators
239 // are in scope (for additional details, see libstdc++/3628)
240 template<typename _Tp, typename _Ref, typename _Ptr>
242 operator==(const _Deque_iterator<_Tp, _Ref, _Ptr>& __x,
243 const _Deque_iterator<_Tp, _Ref, _Ptr>& __y)
244 { return __x._M_cur == __y._M_cur; }
246 template<typename _Tp, typename _RefL, typename _PtrL,
247 typename _RefR, typename _PtrR>
249 operator==(const _Deque_iterator<_Tp, _RefL, _PtrL>& __x,
250 const _Deque_iterator<_Tp, _RefR, _PtrR>& __y)
251 { return __x._M_cur == __y._M_cur; }
253 template<typename _Tp, typename _Ref, typename _Ptr>
255 operator!=(const _Deque_iterator<_Tp, _Ref, _Ptr>& __x,
256 const _Deque_iterator<_Tp, _Ref, _Ptr>& __y)
257 { return !(__x == __y); }
259 template<typename _Tp, typename _RefL, typename _PtrL,
260 typename _RefR, typename _PtrR>
262 operator!=(const _Deque_iterator<_Tp, _RefL, _PtrL>& __x,
263 const _Deque_iterator<_Tp, _RefR, _PtrR>& __y)
264 { return !(__x == __y); }
266 template<typename _Tp, typename _Ref, typename _Ptr>
268 operator<(const _Deque_iterator<_Tp, _Ref, _Ptr>& __x,
269 const _Deque_iterator<_Tp, _Ref, _Ptr>& __y)
270 { return (__x._M_node == __y._M_node) ? (__x._M_cur < __y._M_cur)
271 : (__x._M_node < __y._M_node); }
273 template<typename _Tp, typename _RefL, typename _PtrL,
274 typename _RefR, typename _PtrR>
276 operator<(const _Deque_iterator<_Tp, _RefL, _PtrL>& __x,
277 const _Deque_iterator<_Tp, _RefR, _PtrR>& __y)
278 { return (__x._M_node == __y._M_node) ? (__x._M_cur < __y._M_cur)
279 : (__x._M_node < __y._M_node); }
281 template<typename _Tp, typename _Ref, typename _Ptr>
283 operator>(const _Deque_iterator<_Tp, _Ref, _Ptr>& __x,
284 const _Deque_iterator<_Tp, _Ref, _Ptr>& __y)
285 { return __y < __x; }
287 template<typename _Tp, typename _RefL, typename _PtrL,
288 typename _RefR, typename _PtrR>
290 operator>(const _Deque_iterator<_Tp, _RefL, _PtrL>& __x,
291 const _Deque_iterator<_Tp, _RefR, _PtrR>& __y)
292 { return __y < __x; }
294 template<typename _Tp, typename _Ref, typename _Ptr>
296 operator<=(const _Deque_iterator<_Tp, _Ref, _Ptr>& __x,
297 const _Deque_iterator<_Tp, _Ref, _Ptr>& __y)
298 { return !(__y < __x); }
300 template<typename _Tp, typename _RefL, typename _PtrL,
301 typename _RefR, typename _PtrR>
303 operator<=(const _Deque_iterator<_Tp, _RefL, _PtrL>& __x,
304 const _Deque_iterator<_Tp, _RefR, _PtrR>& __y)
305 { return !(__y < __x); }
307 template<typename _Tp, typename _Ref, typename _Ptr>
309 operator>=(const _Deque_iterator<_Tp, _Ref, _Ptr>& __x,
310 const _Deque_iterator<_Tp, _Ref, _Ptr>& __y)
311 { return !(__x < __y); }
313 template<typename _Tp, typename _RefL, typename _PtrL,
314 typename _RefR, typename _PtrR>
316 operator>=(const _Deque_iterator<_Tp, _RefL, _PtrL>& __x,
317 const _Deque_iterator<_Tp, _RefR, _PtrR>& __y)
318 { return !(__x < __y); }
320 // _GLIBCXX_RESOLVE_LIB_DEFECTS
321 // According to the resolution of DR179 not only the various comparison
322 // operators but also operator- must accept mixed iterator/const_iterator
324 template<typename _Tp, typename _RefL, typename _PtrL,
325 typename _RefR, typename _PtrR>
326 inline typename _Deque_iterator<_Tp, _RefL, _PtrL>::difference_type
327 operator-(const _Deque_iterator<_Tp, _RefL, _PtrL>& __x,
328 const _Deque_iterator<_Tp, _RefR, _PtrR>& __y)
330 return typename _Deque_iterator<_Tp, _RefL, _PtrL>::difference_type
331 (_Deque_iterator<_Tp, _RefL, _PtrL>::_S_buffer_size())
332 * (__x._M_node - __y._M_node - 1) + (__x._M_cur - __x._M_first)
333 + (__y._M_last - __y._M_cur);
336 template<typename _Tp, typename _Ref, typename _Ptr>
337 inline _Deque_iterator<_Tp, _Ref, _Ptr>
338 operator+(ptrdiff_t __n, const _Deque_iterator<_Tp, _Ref, _Ptr>& __x)
339 { return __x + __n; }
343 * Deque base class. This class provides the unified face for %deque's
344 * allocation. This class's constructor and destructor allocate and
345 * deallocate (but do not initialize) storage. This makes %exception
348 * Nothing in this class ever constructs or destroys an actual Tp element.
349 * (Deque handles that itself.) Only/All memory management is performed
353 template<typename _Tp, typename _Alloc>
357 typedef _Alloc allocator_type;
360 get_allocator() const
361 { return _M_get_Tp_allocator(); }
363 typedef _Deque_iterator<_Tp, _Tp&, _Tp*> iterator;
364 typedef _Deque_iterator<_Tp, const _Tp&, const _Tp*> const_iterator;
366 _Deque_base(const allocator_type& __a, size_t __num_elements)
368 { _M_initialize_map(__num_elements); }
370 _Deque_base(const allocator_type& __a)
377 //This struct encapsulates the implementation of the std::deque
378 //standard container and at the same time makes use of the EBO
379 //for empty allocators.
380 typedef typename _Alloc::template rebind<_Tp*>::other _Map_alloc_type;
382 typedef typename _Alloc::template rebind<_Tp>::other _Tp_alloc_type;
385 : public _Tp_alloc_type
392 _Deque_impl(const _Tp_alloc_type& __a)
393 : _Tp_alloc_type(__a), _M_map(0), _M_map_size(0),
394 _M_start(), _M_finish()
399 _M_get_Tp_allocator() const
400 { return *static_cast<const _Tp_alloc_type*>(&this->_M_impl); }
403 _M_get_map_allocator() const
404 { return _M_get_Tp_allocator(); }
409 return _M_impl._Tp_alloc_type::allocate(__deque_buf_size(sizeof(_Tp)));
413 _M_deallocate_node(_Tp* __p)
415 _M_impl._Tp_alloc_type::deallocate(__p, __deque_buf_size(sizeof(_Tp)));
419 _M_allocate_map(size_t __n)
420 { return _M_get_map_allocator().allocate(__n); }
423 _M_deallocate_map(_Tp** __p, size_t __n)
424 { _M_get_map_allocator().deallocate(__p, __n); }
427 void _M_initialize_map(size_t);
428 void _M_create_nodes(_Tp** __nstart, _Tp** __nfinish);
429 void _M_destroy_nodes(_Tp** __nstart, _Tp** __nfinish);
430 enum { _S_initial_map_size = 8 };
435 template<typename _Tp, typename _Alloc>
436 _Deque_base<_Tp, _Alloc>::
439 if (this->_M_impl._M_map)
441 _M_destroy_nodes(this->_M_impl._M_start._M_node,
442 this->_M_impl._M_finish._M_node + 1);
443 _M_deallocate_map(this->_M_impl._M_map, this->_M_impl._M_map_size);
449 * @brief Layout storage.
450 * @param num_elements The count of T's for which to allocate space
454 * The initial underlying memory layout is a bit complicated...
457 template<typename _Tp, typename _Alloc>
459 _Deque_base<_Tp, _Alloc>::
460 _M_initialize_map(size_t __num_elements)
462 const size_t __num_nodes = (__num_elements/ __deque_buf_size(sizeof(_Tp))
465 this->_M_impl._M_map_size = std::max((size_t) _S_initial_map_size,
466 size_t(__num_nodes + 2));
467 this->_M_impl._M_map = _M_allocate_map(this->_M_impl._M_map_size);
469 // For "small" maps (needing less than _M_map_size nodes), allocation
470 // starts in the middle elements and grows outwards. So nstart may be
471 // the beginning of _M_map, but for small maps it may be as far in as
474 _Tp** __nstart = (this->_M_impl._M_map
475 + (this->_M_impl._M_map_size - __num_nodes) / 2);
476 _Tp** __nfinish = __nstart + __num_nodes;
479 { _M_create_nodes(__nstart, __nfinish); }
482 _M_deallocate_map(this->_M_impl._M_map, this->_M_impl._M_map_size);
483 this->_M_impl._M_map = 0;
484 this->_M_impl._M_map_size = 0;
485 __throw_exception_again;
488 this->_M_impl._M_start._M_set_node(__nstart);
489 this->_M_impl._M_finish._M_set_node(__nfinish - 1);
490 this->_M_impl._M_start._M_cur = _M_impl._M_start._M_first;
491 this->_M_impl._M_finish._M_cur = (this->_M_impl._M_finish._M_first
493 % __deque_buf_size(sizeof(_Tp)));
496 template<typename _Tp, typename _Alloc>
498 _Deque_base<_Tp, _Alloc>::
499 _M_create_nodes(_Tp** __nstart, _Tp** __nfinish)
504 for (__cur = __nstart; __cur < __nfinish; ++__cur)
505 *__cur = this->_M_allocate_node();
509 _M_destroy_nodes(__nstart, __cur);
510 __throw_exception_again;
514 template<typename _Tp, typename _Alloc>
516 _Deque_base<_Tp, _Alloc>::
517 _M_destroy_nodes(_Tp** __nstart, _Tp** __nfinish)
519 for (_Tp** __n = __nstart; __n < __nfinish; ++__n)
520 _M_deallocate_node(*__n);
524 * @brief A standard container using fixed-size memory allocation and
525 * constant-time manipulation of elements at either end.
527 * @ingroup Containers
530 * Meets the requirements of a <a href="tables.html#65">container</a>, a
531 * <a href="tables.html#66">reversible container</a>, and a
532 * <a href="tables.html#67">sequence</a>, including the
533 * <a href="tables.html#68">optional sequence requirements</a>.
535 * In previous HP/SGI versions of deque, there was an extra template
536 * parameter so users could control the node size. This extension turned
537 * out to violate the C++ standard (it can be detected using template
538 * template parameters), and it was removed.
541 * Here's how a deque<Tp> manages memory. Each deque has 4 members:
544 * - size_t _M_map_size
545 * - iterator _M_start, _M_finish
547 * map_size is at least 8. %map is an array of map_size
548 * pointers-to-"nodes". (The name %map has nothing to do with the
549 * std::map class, and "nodes" should not be confused with
550 * std::list's usage of "node".)
552 * A "node" has no specific type name as such, but it is referred
553 * to as "node" in this file. It is a simple array-of-Tp. If Tp
554 * is very large, there will be one Tp element per node (i.e., an
555 * "array" of one). For non-huge Tp's, node size is inversely
556 * related to Tp size: the larger the Tp, the fewer Tp's will fit
557 * in a node. The goal here is to keep the total size of a node
558 * relatively small and constant over different Tp's, to improve
559 * allocator efficiency.
561 * Not every pointer in the %map array will point to a node. If
562 * the initial number of elements in the deque is small, the
563 * /middle/ %map pointers will be valid, and the ones at the edges
564 * will be unused. This same situation will arise as the %map
565 * grows: available %map pointers, if any, will be on the ends. As
566 * new nodes are created, only a subset of the %map's pointers need
567 * to be copied "outward".
570 * - For any nonsingular iterator i:
571 * - i.node points to a member of the %map array. (Yes, you read that
572 * correctly: i.node does not actually point to a node.) The member of
573 * the %map array is what actually points to the node.
574 * - i.first == *(i.node) (This points to the node (first Tp element).)
575 * - i.last == i.first + node_size
576 * - i.cur is a pointer in the range [i.first, i.last). NOTE:
577 * the implication of this is that i.cur is always a dereferenceable
578 * pointer, even if i is a past-the-end iterator.
579 * - Start and Finish are always nonsingular iterators. NOTE: this
580 * means that an empty deque must have one node, a deque with <N
581 * elements (where N is the node buffer size) must have one node, a
582 * deque with N through (2N-1) elements must have two nodes, etc.
583 * - For every node other than start.node and finish.node, every
584 * element in the node is an initialized object. If start.node ==
585 * finish.node, then [start.cur, finish.cur) are initialized
586 * objects, and the elements outside that range are uninitialized
587 * storage. Otherwise, [start.cur, start.last) and [finish.first,
588 * finish.cur) are initialized objects, and [start.first, start.cur)
589 * and [finish.cur, finish.last) are uninitialized storage.
590 * - [%map, %map + map_size) is a valid, non-empty range.
591 * - [start.node, finish.node] is a valid range contained within
592 * [%map, %map + map_size).
593 * - A pointer in the range [%map, %map + map_size) points to an allocated
594 * node if and only if the pointer is in the range
595 * [start.node, finish.node].
597 * Here's the magic: nothing in deque is "aware" of the discontiguous
600 * The memory setup and layout occurs in the parent, _Base, and the iterator
601 * class is entirely responsible for "leaping" from one node to the next.
602 * All the implementation routines for deque itself work only through the
603 * start and finish iterators. This keeps the routines simple and sane,
604 * and we can use other standard algorithms as well.
607 template<typename _Tp, typename _Alloc = std::allocator<_Tp> >
608 class deque : protected _Deque_base<_Tp, _Alloc>
610 // concept requirements
611 typedef typename _Alloc::value_type _Alloc_value_type;
612 __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
613 __glibcxx_class_requires2(_Tp, _Alloc_value_type, _SameTypeConcept)
615 typedef _Deque_base<_Tp, _Alloc> _Base;
616 typedef typename _Base::_Tp_alloc_type _Tp_alloc_type;
619 typedef _Tp value_type;
620 typedef typename _Tp_alloc_type::pointer pointer;
621 typedef typename _Tp_alloc_type::const_pointer const_pointer;
622 typedef typename _Tp_alloc_type::reference reference;
623 typedef typename _Tp_alloc_type::const_reference const_reference;
624 typedef typename _Base::iterator iterator;
625 typedef typename _Base::const_iterator const_iterator;
626 typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
627 typedef std::reverse_iterator<iterator> reverse_iterator;
628 typedef size_t size_type;
629 typedef ptrdiff_t difference_type;
630 typedef _Alloc allocator_type;
633 typedef pointer* _Map_pointer;
635 static size_t _S_buffer_size()
636 { return __deque_buf_size(sizeof(_Tp)); }
638 // Functions controlling memory layout, and nothing else.
639 using _Base::_M_initialize_map;
640 using _Base::_M_create_nodes;
641 using _Base::_M_destroy_nodes;
642 using _Base::_M_allocate_node;
643 using _Base::_M_deallocate_node;
644 using _Base::_M_allocate_map;
645 using _Base::_M_deallocate_map;
646 using _Base::_M_get_Tp_allocator;
649 * A total of four data members accumulated down the heirarchy.
650 * May be accessed via _M_impl.*
653 using _Base::_M_impl;
656 // [23.2.1.1] construct/copy/destroy
657 // (assign() and get_allocator() are also listed in this section)
659 * @brief Default constructor creates no elements.
662 deque(const allocator_type& __a = allocator_type())
666 * @brief Create a %deque with copies of an exemplar element.
667 * @param n The number of elements to initially create.
668 * @param value An element to copy.
670 * This constructor fills the %deque with @a n copies of @a value.
673 deque(size_type __n, const value_type& __value = value_type(),
674 const allocator_type& __a = allocator_type())
676 { _M_fill_initialize(__value); }
679 * @brief %Deque copy constructor.
680 * @param x A %deque of identical element and allocator types.
682 * The newly-created %deque uses a copy of the allocation object used
685 deque(const deque& __x)
686 : _Base(__x.get_allocator(), __x.size())
687 { std::__uninitialized_copy_a(__x.begin(), __x.end(),
688 this->_M_impl._M_start,
689 _M_get_Tp_allocator()); }
692 * @brief Builds a %deque from a range.
693 * @param first An input iterator.
694 * @param last An input iterator.
696 * Create a %deque consisting of copies of the elements from [first,
699 * If the iterators are forward, bidirectional, or random-access, then
700 * this will call the elements' copy constructor N times (where N is
701 * distance(first,last)) and do no memory reallocation. But if only
702 * input iterators are used, then this will do at most 2N calls to the
703 * copy constructor, and logN memory reallocations.
705 template<typename _InputIterator>
706 deque(_InputIterator __first, _InputIterator __last,
707 const allocator_type& __a = allocator_type())
710 // Check whether it's an integral type. If so, it's not an iterator.
711 typedef typename std::__is_integer<_InputIterator>::__type _Integral;
712 _M_initialize_dispatch(__first, __last, _Integral());
716 * The dtor only erases the elements, and note that if the elements
717 * themselves are pointers, the pointed-to memory is not touched in any
718 * way. Managing the pointer is the user's responsibilty.
721 { std::_Destroy(this->_M_impl._M_start, this->_M_impl._M_finish,
722 _M_get_Tp_allocator()); }
725 * @brief %Deque assignment operator.
726 * @param x A %deque of identical element and allocator types.
728 * All the elements of @a x are copied, but unlike the copy constructor,
729 * the allocator object is not copied.
732 operator=(const deque& __x);
735 * @brief Assigns a given value to a %deque.
736 * @param n Number of elements to be assigned.
737 * @param val Value to be assigned.
739 * This function fills a %deque with @a n copies of the given
740 * value. Note that the assignment completely changes the
741 * %deque and that the resulting %deque's size is the same as
742 * the number of elements assigned. Old data may be lost.
745 assign(size_type __n, const value_type& __val)
746 { _M_fill_assign(__n, __val); }
749 * @brief Assigns a range to a %deque.
750 * @param first An input iterator.
751 * @param last An input iterator.
753 * This function fills a %deque with copies of the elements in the
754 * range [first,last).
756 * Note that the assignment completely changes the %deque and that the
757 * resulting %deque's size is the same as the number of elements
758 * assigned. Old data may be lost.
760 template<typename _InputIterator>
762 assign(_InputIterator __first, _InputIterator __last)
764 typedef typename std::__is_integer<_InputIterator>::__type _Integral;
765 _M_assign_dispatch(__first, __last, _Integral());
768 /// Get a copy of the memory allocation object.
770 get_allocator() const
771 { return _Base::get_allocator(); }
775 * Returns a read/write iterator that points to the first element in the
776 * %deque. Iteration is done in ordinary element order.
780 { return this->_M_impl._M_start; }
783 * Returns a read-only (constant) iterator that points to the first
784 * element in the %deque. Iteration is done in ordinary element order.
788 { return this->_M_impl._M_start; }
791 * Returns a read/write iterator that points one past the last
792 * element in the %deque. Iteration is done in ordinary
797 { return this->_M_impl._M_finish; }
800 * Returns a read-only (constant) iterator that points one past
801 * the last element in the %deque. Iteration is done in
802 * ordinary element order.
806 { return this->_M_impl._M_finish; }
809 * Returns a read/write reverse iterator that points to the
810 * last element in the %deque. Iteration is done in reverse
815 { return reverse_iterator(this->_M_impl._M_finish); }
818 * Returns a read-only (constant) reverse iterator that points
819 * to the last element in the %deque. Iteration is done in
820 * reverse element order.
822 const_reverse_iterator
824 { return const_reverse_iterator(this->_M_impl._M_finish); }
827 * Returns a read/write reverse iterator that points to one
828 * before the first element in the %deque. Iteration is done
829 * in reverse element order.
832 rend() { return reverse_iterator(this->_M_impl._M_start); }
835 * Returns a read-only (constant) reverse iterator that points
836 * to one before the first element in the %deque. Iteration is
837 * done in reverse element order.
839 const_reverse_iterator
841 { return const_reverse_iterator(this->_M_impl._M_start); }
843 // [23.2.1.2] capacity
844 /** Returns the number of elements in the %deque. */
847 { return this->_M_impl._M_finish - this->_M_impl._M_start; }
849 /** Returns the size() of the largest possible %deque. */
852 { return size_type(-1); }
855 * @brief Resizes the %deque to the specified number of elements.
856 * @param new_size Number of elements the %deque should contain.
857 * @param x Data with which new elements should be populated.
859 * This function will %resize the %deque to the specified
860 * number of elements. If the number is smaller than the
861 * %deque's current size the %deque is truncated, otherwise the
862 * %deque is extended and new elements are populated with given
866 resize(size_type __new_size, value_type __x = value_type())
868 const size_type __len = size();
869 if (__new_size < __len)
870 erase(this->_M_impl._M_start + __new_size, this->_M_impl._M_finish);
872 insert(this->_M_impl._M_finish, __new_size - __len, __x);
876 * Returns true if the %deque is empty. (Thus begin() would
881 { return this->_M_impl._M_finish == this->_M_impl._M_start; }
885 * @brief Subscript access to the data contained in the %deque.
886 * @param n The index of the element for which data should be
888 * @return Read/write reference to data.
890 * This operator allows for easy, array-style, data access.
891 * Note that data access with this operator is unchecked and
892 * out_of_range lookups are not defined. (For checked lookups
896 operator[](size_type __n)
897 { return this->_M_impl._M_start[difference_type(__n)]; }
900 * @brief Subscript access to the data contained in the %deque.
901 * @param n The index of the element for which data should be
903 * @return Read-only (constant) reference to data.
905 * This operator allows for easy, array-style, data access.
906 * Note that data access with this operator is unchecked and
907 * out_of_range lookups are not defined. (For checked lookups
911 operator[](size_type __n) const
912 { return this->_M_impl._M_start[difference_type(__n)]; }
915 /// @if maint Safety check used only from at(). @endif
917 _M_range_check(size_type __n) const
919 if (__n >= this->size())
920 __throw_out_of_range(__N("deque::_M_range_check"));
925 * @brief Provides access to the data contained in the %deque.
926 * @param n The index of the element for which data should be
928 * @return Read/write reference to data.
929 * @throw std::out_of_range If @a n is an invalid index.
931 * This function provides for safer data access. The parameter
932 * is first checked that it is in the range of the deque. The
933 * function throws out_of_range if the check fails.
943 * @brief Provides access to the data contained in the %deque.
944 * @param n The index of the element for which data should be
946 * @return Read-only (constant) reference to data.
947 * @throw std::out_of_range If @a n is an invalid index.
949 * This function provides for safer data access. The parameter is first
950 * checked that it is in the range of the deque. The function throws
951 * out_of_range if the check fails.
954 at(size_type __n) const
961 * Returns a read/write reference to the data at the first
962 * element of the %deque.
969 * Returns a read-only (constant) reference to the data at the first
970 * element of the %deque.
977 * Returns a read/write reference to the data at the last element of the
983 iterator __tmp = end();
989 * Returns a read-only (constant) reference to the data at the last
990 * element of the %deque.
995 const_iterator __tmp = end();
1000 // [23.2.1.2] modifiers
1002 * @brief Add data to the front of the %deque.
1003 * @param x Data to be added.
1005 * This is a typical stack operation. The function creates an
1006 * element at the front of the %deque and assigns the given
1007 * data to it. Due to the nature of a %deque this operation
1008 * can be done in constant time.
1011 push_front(const value_type& __x)
1013 if (this->_M_impl._M_start._M_cur != this->_M_impl._M_start._M_first)
1015 this->_M_impl.construct(this->_M_impl._M_start._M_cur - 1, __x);
1016 --this->_M_impl._M_start._M_cur;
1019 _M_push_front_aux(__x);
1023 * @brief Add data to the end of the %deque.
1024 * @param x Data to be added.
1026 * This is a typical stack operation. The function creates an
1027 * element at the end of the %deque and assigns the given data
1028 * to it. Due to the nature of a %deque this operation can be
1029 * done in constant time.
1032 push_back(const value_type& __x)
1034 if (this->_M_impl._M_finish._M_cur
1035 != this->_M_impl._M_finish._M_last - 1)
1037 this->_M_impl.construct(this->_M_impl._M_finish._M_cur, __x);
1038 ++this->_M_impl._M_finish._M_cur;
1041 _M_push_back_aux(__x);
1045 * @brief Removes first element.
1047 * This is a typical stack operation. It shrinks the %deque by one.
1049 * Note that no data is returned, and if the first element's data is
1050 * needed, it should be retrieved before pop_front() is called.
1055 if (this->_M_impl._M_start._M_cur
1056 != this->_M_impl._M_start._M_last - 1)
1058 this->_M_impl.destroy(this->_M_impl._M_start._M_cur);
1059 ++this->_M_impl._M_start._M_cur;
1066 * @brief Removes last element.
1068 * This is a typical stack operation. It shrinks the %deque by one.
1070 * Note that no data is returned, and if the last element's data is
1071 * needed, it should be retrieved before pop_back() is called.
1076 if (this->_M_impl._M_finish._M_cur
1077 != this->_M_impl._M_finish._M_first)
1079 --this->_M_impl._M_finish._M_cur;
1080 this->_M_impl.destroy(this->_M_impl._M_finish._M_cur);
1087 * @brief Inserts given value into %deque before specified iterator.
1088 * @param position An iterator into the %deque.
1089 * @param x Data to be inserted.
1090 * @return An iterator that points to the inserted data.
1092 * This function will insert a copy of the given value before the
1093 * specified location.
1096 insert(iterator position, const value_type& __x);
1099 * @brief Inserts a number of copies of given data into the %deque.
1100 * @param position An iterator into the %deque.
1101 * @param n Number of elements to be inserted.
1102 * @param x Data to be inserted.
1104 * This function will insert a specified number of copies of the given
1105 * data before the location specified by @a position.
1108 insert(iterator __position, size_type __n, const value_type& __x)
1109 { _M_fill_insert(__position, __n, __x); }
1112 * @brief Inserts a range into the %deque.
1113 * @param position An iterator into the %deque.
1114 * @param first An input iterator.
1115 * @param last An input iterator.
1117 * This function will insert copies of the data in the range
1118 * [first,last) into the %deque before the location specified
1119 * by @a pos. This is known as "range insert."
1121 template<typename _InputIterator>
1123 insert(iterator __position, _InputIterator __first,
1124 _InputIterator __last)
1126 // Check whether it's an integral type. If so, it's not an iterator.
1127 typedef typename std::__is_integer<_InputIterator>::__type _Integral;
1128 _M_insert_dispatch(__position, __first, __last, _Integral());
1132 * @brief Remove element at given position.
1133 * @param position Iterator pointing to element to be erased.
1134 * @return An iterator pointing to the next element (or end()).
1136 * This function will erase the element at the given position and thus
1137 * shorten the %deque by one.
1139 * The user is cautioned that
1140 * this function only erases the element, and that if the element is
1141 * itself a pointer, the pointed-to memory is not touched in any way.
1142 * Managing the pointer is the user's responsibilty.
1145 erase(iterator __position);
1148 * @brief Remove a range of elements.
1149 * @param first Iterator pointing to the first element to be erased.
1150 * @param last Iterator pointing to one past the last element to be
1152 * @return An iterator pointing to the element pointed to by @a last
1153 * prior to erasing (or end()).
1155 * This function will erase the elements in the range [first,last) and
1156 * shorten the %deque accordingly.
1158 * The user is cautioned that
1159 * this function only erases the elements, and that if the elements
1160 * themselves are pointers, the pointed-to memory is not touched in any
1161 * way. Managing the pointer is the user's responsibilty.
1164 erase(iterator __first, iterator __last);
1167 * @brief Swaps data with another %deque.
1168 * @param x A %deque of the same element and allocator types.
1170 * This exchanges the elements between two deques in constant time.
1171 * (Four pointers, so it should be quite fast.)
1172 * Note that the global std::swap() function is specialized such that
1173 * std::swap(d1,d2) will feed to this function.
1178 std::swap(this->_M_impl._M_start, __x._M_impl._M_start);
1179 std::swap(this->_M_impl._M_finish, __x._M_impl._M_finish);
1180 std::swap(this->_M_impl._M_map, __x._M_impl._M_map);
1181 std::swap(this->_M_impl._M_map_size, __x._M_impl._M_map_size);
1185 * Erases all the elements. Note that this function only erases the
1186 * elements, and that if the elements themselves are pointers, the
1187 * pointed-to memory is not touched in any way. Managing the pointer is
1188 * the user's responsibilty.
1193 // Internal constructor functions follow.
1195 // called by the range constructor to implement [23.1.1]/9
1196 template<typename _Integer>
1198 _M_initialize_dispatch(_Integer __n, _Integer __x, __true_type)
1200 _M_initialize_map(__n);
1201 _M_fill_initialize(__x);
1204 // called by the range constructor to implement [23.1.1]/9
1205 template<typename _InputIterator>
1207 _M_initialize_dispatch(_InputIterator __first, _InputIterator __last,
1210 typedef typename std::iterator_traits<_InputIterator>::
1211 iterator_category _IterCategory;
1212 _M_range_initialize(__first, __last, _IterCategory());
1215 // called by the second initialize_dispatch above
1219 * @brief Fills the deque with whatever is in [first,last).
1220 * @param first An input iterator.
1221 * @param last An input iterator.
1224 * If the iterators are actually forward iterators (or better), then the
1225 * memory layout can be done all at once. Else we move forward using
1226 * push_back on each value from the iterator.
1229 template<typename _InputIterator>
1231 _M_range_initialize(_InputIterator __first, _InputIterator __last,
1232 std::input_iterator_tag);
1234 // called by the second initialize_dispatch above
1235 template<typename _ForwardIterator>
1237 _M_range_initialize(_ForwardIterator __first, _ForwardIterator __last,
1238 std::forward_iterator_tag);
1243 * @brief Fills the %deque with copies of value.
1244 * @param value Initial value.
1246 * @pre _M_start and _M_finish have already been initialized,
1247 * but none of the %deque's elements have yet been constructed.
1249 * This function is called only when the user provides an explicit size
1250 * (with or without an explicit exemplar value).
1254 _M_fill_initialize(const value_type& __value);
1256 // Internal assign functions follow. The *_aux functions do the actual
1257 // assignment work for the range versions.
1259 // called by the range assign to implement [23.1.1]/9
1260 template<typename _Integer>
1262 _M_assign_dispatch(_Integer __n, _Integer __val, __true_type)
1264 _M_fill_assign(static_cast<size_type>(__n),
1265 static_cast<value_type>(__val));
1268 // called by the range assign to implement [23.1.1]/9
1269 template<typename _InputIterator>
1271 _M_assign_dispatch(_InputIterator __first, _InputIterator __last,
1274 typedef typename std::iterator_traits<_InputIterator>::
1275 iterator_category _IterCategory;
1276 _M_assign_aux(__first, __last, _IterCategory());
1279 // called by the second assign_dispatch above
1280 template<typename _InputIterator>
1282 _M_assign_aux(_InputIterator __first, _InputIterator __last,
1283 std::input_iterator_tag);
1285 // called by the second assign_dispatch above
1286 template<typename _ForwardIterator>
1288 _M_assign_aux(_ForwardIterator __first, _ForwardIterator __last,
1289 std::forward_iterator_tag)
1291 const size_type __len = std::distance(__first, __last);
1294 _ForwardIterator __mid = __first;
1295 std::advance(__mid, size());
1296 std::copy(__first, __mid, begin());
1297 insert(end(), __mid, __last);
1300 erase(std::copy(__first, __last, begin()), end());
1303 // Called by assign(n,t), and the range assign when it turns out
1304 // to be the same thing.
1306 _M_fill_assign(size_type __n, const value_type& __val)
1310 std::fill(begin(), end(), __val);
1311 insert(end(), __n - size(), __val);
1315 erase(begin() + __n, end());
1316 std::fill(begin(), end(), __val);
1323 * @brief Helper functions for push_* and pop_*.
1326 void _M_push_back_aux(const value_type&);
1327 void _M_push_front_aux(const value_type&);
1328 void _M_pop_back_aux();
1329 void _M_pop_front_aux();
1332 // Internal insert functions follow. The *_aux functions do the actual
1333 // insertion work when all shortcuts fail.
1335 // called by the range insert to implement [23.1.1]/9
1336 template<typename _Integer>
1338 _M_insert_dispatch(iterator __pos,
1339 _Integer __n, _Integer __x, __true_type)
1341 _M_fill_insert(__pos, static_cast<size_type>(__n),
1342 static_cast<value_type>(__x));
1345 // called by the range insert to implement [23.1.1]/9
1346 template<typename _InputIterator>
1348 _M_insert_dispatch(iterator __pos,
1349 _InputIterator __first, _InputIterator __last,
1352 typedef typename std::iterator_traits<_InputIterator>::
1353 iterator_category _IterCategory;
1354 _M_range_insert_aux(__pos, __first, __last, _IterCategory());
1357 // called by the second insert_dispatch above
1358 template<typename _InputIterator>
1360 _M_range_insert_aux(iterator __pos, _InputIterator __first,
1361 _InputIterator __last, std::input_iterator_tag);
1363 // called by the second insert_dispatch above
1364 template<typename _ForwardIterator>
1366 _M_range_insert_aux(iterator __pos, _ForwardIterator __first,
1367 _ForwardIterator __last, std::forward_iterator_tag);
1369 // Called by insert(p,n,x), and the range insert when it turns out to be
1370 // the same thing. Can use fill functions in optimal situations,
1371 // otherwise passes off to insert_aux(p,n,x).
1373 _M_fill_insert(iterator __pos, size_type __n, const value_type& __x);
1375 // called by insert(p,x)
1377 _M_insert_aux(iterator __pos, const value_type& __x);
1379 // called by insert(p,n,x) via fill_insert
1381 _M_insert_aux(iterator __pos, size_type __n, const value_type& __x);
1383 // called by range_insert_aux for forward iterators
1384 template<typename _ForwardIterator>
1386 _M_insert_aux(iterator __pos,
1387 _ForwardIterator __first, _ForwardIterator __last,
1393 * @brief Memory-handling helpers for the previous internal insert
1398 _M_reserve_elements_at_front(size_type __n)
1400 const size_type __vacancies = this->_M_impl._M_start._M_cur
1401 - this->_M_impl._M_start._M_first;
1402 if (__n > __vacancies)
1403 _M_new_elements_at_front(__n - __vacancies);
1404 return this->_M_impl._M_start - difference_type(__n);
1408 _M_reserve_elements_at_back(size_type __n)
1410 const size_type __vacancies = (this->_M_impl._M_finish._M_last
1411 - this->_M_impl._M_finish._M_cur) - 1;
1412 if (__n > __vacancies)
1413 _M_new_elements_at_back(__n - __vacancies);
1414 return this->_M_impl._M_finish + difference_type(__n);
1418 _M_new_elements_at_front(size_type __new_elements);
1421 _M_new_elements_at_back(size_type __new_elements);
1428 * @brief Memory-handling helpers for the major %map.
1430 * Makes sure the _M_map has space for new nodes. Does not
1431 * actually add the nodes. Can invalidate _M_map pointers.
1432 * (And consequently, %deque iterators.)
1436 _M_reserve_map_at_back (size_type __nodes_to_add = 1)
1438 if (__nodes_to_add + 1 > this->_M_impl._M_map_size
1439 - (this->_M_impl._M_finish._M_node - this->_M_impl._M_map))
1440 _M_reallocate_map(__nodes_to_add, false);
1444 _M_reserve_map_at_front (size_type __nodes_to_add = 1)
1446 if (__nodes_to_add > size_type(this->_M_impl._M_start._M_node
1447 - this->_M_impl._M_map))
1448 _M_reallocate_map(__nodes_to_add, true);
1452 _M_reallocate_map(size_type __nodes_to_add, bool __add_at_front);
1458 * @brief Deque equality comparison.
1459 * @param x A %deque.
1460 * @param y A %deque of the same type as @a x.
1461 * @return True iff the size and elements of the deques are equal.
1463 * This is an equivalence relation. It is linear in the size of the
1464 * deques. Deques are considered equivalent if their sizes are equal,
1465 * and if corresponding elements compare equal.
1467 template<typename _Tp, typename _Alloc>
1469 operator==(const deque<_Tp, _Alloc>& __x,
1470 const deque<_Tp, _Alloc>& __y)
1471 { return __x.size() == __y.size()
1472 && std::equal(__x.begin(), __x.end(), __y.begin()); }
1475 * @brief Deque ordering relation.
1476 * @param x A %deque.
1477 * @param y A %deque of the same type as @a x.
1478 * @return True iff @a x is lexicographically less than @a y.
1480 * This is a total ordering relation. It is linear in the size of the
1481 * deques. The elements must be comparable with @c <.
1483 * See std::lexicographical_compare() for how the determination is made.
1485 template<typename _Tp, typename _Alloc>
1487 operator<(const deque<_Tp, _Alloc>& __x,
1488 const deque<_Tp, _Alloc>& __y)
1489 { return lexicographical_compare(__x.begin(), __x.end(),
1490 __y.begin(), __y.end()); }
1492 /// Based on operator==
1493 template<typename _Tp, typename _Alloc>
1495 operator!=(const deque<_Tp, _Alloc>& __x,
1496 const deque<_Tp, _Alloc>& __y)
1497 { return !(__x == __y); }
1499 /// Based on operator<
1500 template<typename _Tp, typename _Alloc>
1502 operator>(const deque<_Tp, _Alloc>& __x,
1503 const deque<_Tp, _Alloc>& __y)
1504 { return __y < __x; }
1506 /// Based on operator<
1507 template<typename _Tp, typename _Alloc>
1509 operator<=(const deque<_Tp, _Alloc>& __x,
1510 const deque<_Tp, _Alloc>& __y)
1511 { return !(__y < __x); }
1513 /// Based on operator<
1514 template<typename _Tp, typename _Alloc>
1516 operator>=(const deque<_Tp, _Alloc>& __x,
1517 const deque<_Tp, _Alloc>& __y)
1518 { return !(__x < __y); }
1520 /// See std::deque::swap().
1521 template<typename _Tp, typename _Alloc>
1523 swap(deque<_Tp,_Alloc>& __x, deque<_Tp,_Alloc>& __y)
1527 #endif /* _DEQUE_H */