1 // Deque implementation -*- C++ -*-
3 // Copyright (C) 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
5 // This file is part of the GNU ISO C++ Library. This library is free
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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
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14 // GNU General Public License for more details.
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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
23 // templates or use macros or inline functions from this file, or you compile
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33 * Hewlett-Packard Company
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36 * and its documentation for any purpose is hereby granted without fee,
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45 * Silicon Graphics Computer Systems, Inc.
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53 * purpose. It is provided "as is" without express or implied warranty.
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>
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 deque is
91 * actually passed off to this class. A deque holds two of these internally,
92 * marking its valid range. Access to elements is done as offsets of either
93 * of those two, relying on operator overloading in this class.
96 * All the functions are op overloads except for _M_set_node.
99 template<typename _Tp, typename _Ref, typename _Ptr>
100 struct _Deque_iterator
102 typedef _Deque_iterator<_Tp, _Tp&, _Tp*> iterator;
103 typedef _Deque_iterator<_Tp, const _Tp&, const _Tp*> const_iterator;
105 static size_t _S_buffer_size()
106 { return __deque_buf_size(sizeof(_Tp)); }
108 typedef random_access_iterator_tag iterator_category;
109 typedef _Tp value_type;
110 typedef _Ptr pointer;
111 typedef _Ref reference;
112 typedef size_t size_type;
113 typedef ptrdiff_t difference_type;
114 typedef _Tp** _Map_pointer;
115 typedef _Deque_iterator _Self;
120 _Map_pointer _M_node;
122 _Deque_iterator(_Tp* __x, _Map_pointer __y)
123 : _M_cur(__x), _M_first(*__y),
124 _M_last(*__y + _S_buffer_size()), _M_node(__y) {}
126 _Deque_iterator() : _M_cur(0), _M_first(0), _M_last(0), _M_node(0) {}
128 _Deque_iterator(const iterator& __x)
129 : _M_cur(__x._M_cur), _M_first(__x._M_first),
130 _M_last(__x._M_last), _M_node(__x._M_node) {}
144 if (_M_cur == _M_last)
146 _M_set_node(_M_node + 1);
163 if (_M_cur == _M_first)
165 _M_set_node(_M_node - 1);
181 operator+=(difference_type __n)
183 const difference_type __offset = __n + (_M_cur - _M_first);
184 if (__offset >= 0 && __offset < difference_type(_S_buffer_size()))
188 const difference_type __node_offset =
189 __offset > 0 ? __offset / difference_type(_S_buffer_size())
190 : -difference_type((-__offset - 1)
191 / _S_buffer_size()) - 1;
192 _M_set_node(_M_node + __node_offset);
193 _M_cur = _M_first + (__offset - __node_offset
194 * difference_type(_S_buffer_size()));
200 operator+(difference_type __n) const
207 operator-=(difference_type __n)
208 { return *this += -__n; }
211 operator-(difference_type __n) const
218 operator[](difference_type __n) const
219 { return *(*this + __n); }
222 * Prepares to traverse new_node. Sets everything except _M_cur, which
223 * should therefore be set by the caller immediately afterwards, based on
224 * _M_first and _M_last.
228 _M_set_node(_Map_pointer __new_node)
230 _M_node = __new_node;
231 _M_first = *__new_node;
232 _M_last = _M_first + difference_type(_S_buffer_size());
236 // Note: we also provide overloads whose operands are of the same type in
237 // order to avoid ambiguous overload resolution when std::rel_ops operators
238 // are in scope (for additional details, see libstdc++/3628)
239 template<typename _Tp, typename _Ref, typename _Ptr>
241 operator==(const _Deque_iterator<_Tp, _Ref, _Ptr>& __x,
242 const _Deque_iterator<_Tp, _Ref, _Ptr>& __y)
243 { return __x._M_cur == __y._M_cur; }
245 template<typename _Tp, typename _RefL, typename _PtrL,
246 typename _RefR, typename _PtrR>
248 operator==(const _Deque_iterator<_Tp, _RefL, _PtrL>& __x,
249 const _Deque_iterator<_Tp, _RefR, _PtrR>& __y)
250 { return __x._M_cur == __y._M_cur; }
252 template<typename _Tp, typename _Ref, typename _Ptr>
254 operator!=(const _Deque_iterator<_Tp, _Ref, _Ptr>& __x,
255 const _Deque_iterator<_Tp, _Ref, _Ptr>& __y)
256 { return !(__x == __y); }
258 template<typename _Tp, typename _RefL, typename _PtrL,
259 typename _RefR, typename _PtrR>
261 operator!=(const _Deque_iterator<_Tp, _RefL, _PtrL>& __x,
262 const _Deque_iterator<_Tp, _RefR, _PtrR>& __y)
263 { return !(__x == __y); }
265 template<typename _Tp, typename _Ref, typename _Ptr>
267 operator<(const _Deque_iterator<_Tp, _Ref, _Ptr>& __x,
268 const _Deque_iterator<_Tp, _Ref, _Ptr>& __y)
269 { return (__x._M_node == __y._M_node) ? (__x._M_cur < __y._M_cur)
270 : (__x._M_node < __y._M_node); }
272 template<typename _Tp, typename _RefL, typename _PtrL,
273 typename _RefR, typename _PtrR>
275 operator<(const _Deque_iterator<_Tp, _RefL, _PtrL>& __x,
276 const _Deque_iterator<_Tp, _RefR, _PtrR>& __y)
277 { return (__x._M_node == __y._M_node) ? (__x._M_cur < __y._M_cur)
278 : (__x._M_node < __y._M_node); }
280 template<typename _Tp, typename _Ref, typename _Ptr>
282 operator>(const _Deque_iterator<_Tp, _Ref, _Ptr>& __x,
283 const _Deque_iterator<_Tp, _Ref, _Ptr>& __y)
284 { return __y < __x; }
286 template<typename _Tp, typename _RefL, typename _PtrL,
287 typename _RefR, typename _PtrR>
289 operator>(const _Deque_iterator<_Tp, _RefL, _PtrL>& __x,
290 const _Deque_iterator<_Tp, _RefR, _PtrR>& __y)
291 { return __y < __x; }
293 template<typename _Tp, typename _Ref, typename _Ptr>
295 operator<=(const _Deque_iterator<_Tp, _Ref, _Ptr>& __x,
296 const _Deque_iterator<_Tp, _Ref, _Ptr>& __y)
297 { return !(__y < __x); }
299 template<typename _Tp, typename _RefL, typename _PtrL,
300 typename _RefR, typename _PtrR>
302 operator<=(const _Deque_iterator<_Tp, _RefL, _PtrL>& __x,
303 const _Deque_iterator<_Tp, _RefR, _PtrR>& __y)
304 { return !(__y < __x); }
306 template<typename _Tp, typename _Ref, typename _Ptr>
308 operator>=(const _Deque_iterator<_Tp, _Ref, _Ptr>& __x,
309 const _Deque_iterator<_Tp, _Ref, _Ptr>& __y)
310 { return !(__x < __y); }
312 template<typename _Tp, typename _RefL, typename _PtrL,
313 typename _RefR, typename _PtrR>
315 operator>=(const _Deque_iterator<_Tp, _RefL, _PtrL>& __x,
316 const _Deque_iterator<_Tp, _RefR, _PtrR>& __y)
317 { return !(__x < __y); }
319 // _GLIBCXX_RESOLVE_LIB_DEFECTS
320 // According to the resolution of DR179 not only the various comparison
321 // operators but also operator- must accept mixed iterator/const_iterator
323 template<typename _Tp, typename _RefL, typename _PtrL,
324 typename _RefR, typename _PtrR>
325 inline typename _Deque_iterator<_Tp, _RefL, _PtrL>::difference_type
326 operator-(const _Deque_iterator<_Tp, _RefL, _PtrL>& __x,
327 const _Deque_iterator<_Tp, _RefR, _PtrR>& __y)
329 return typename _Deque_iterator<_Tp, _RefL, _PtrL>::difference_type
330 (_Deque_iterator<_Tp, _RefL, _PtrL>::_S_buffer_size())
331 * (__x._M_node - __y._M_node - 1) + (__x._M_cur - __x._M_first)
332 + (__y._M_last - __y._M_cur);
335 template<typename _Tp, typename _Ref, typename _Ptr>
336 inline _Deque_iterator<_Tp, _Ref, _Ptr>
337 operator+(ptrdiff_t __n, const _Deque_iterator<_Tp, _Ref, _Ptr>& __x)
338 { return __x + __n; }
342 * Deque base class. This class provides the unified face for %deque's
343 * allocation. This class's constructor and destructor allocate and
344 * deallocate (but do not initialize) storage. This makes %exception
347 * Nothing in this class ever constructs or destroys an actual Tp element.
348 * (Deque handles that itself.) Only/All memory management is performed
352 template<typename _Tp, typename _Alloc>
357 typedef _Alloc allocator_type;
360 get_allocator() const
361 { return *static_cast<const _Alloc*>(this); }
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)
367 : _Alloc(__a), _M_start(), _M_finish()
368 { _M_initialize_map(__num_elements); }
370 _Deque_base(const allocator_type& __a)
371 : _Alloc(__a), _M_start(), _M_finish() { }
376 typedef typename _Alloc::template rebind<_Tp*>::other _Map_alloc_type;
377 _Map_alloc_type _M_get_map_allocator() const
378 { return _Map_alloc_type(this->get_allocator()); }
382 { return _Alloc::allocate(__deque_buf_size(sizeof(_Tp))); }
385 _M_deallocate_node(_Tp* __p)
386 { _Alloc::deallocate(__p, __deque_buf_size(sizeof(_Tp))); }
389 _M_allocate_map(size_t __n)
390 { return _M_get_map_allocator().allocate(__n); }
393 _M_deallocate_map(_Tp** __p, size_t __n)
394 { _M_get_map_allocator().deallocate(__p, __n); }
397 void _M_initialize_map(size_t);
398 void _M_create_nodes(_Tp** __nstart, _Tp** __nfinish);
399 void _M_destroy_nodes(_Tp** __nstart, _Tp** __nfinish);
400 enum { _S_initial_map_size = 8 };
408 template<typename _Tp, typename _Alloc>
409 _Deque_base<_Tp,_Alloc>::~_Deque_base()
413 _M_destroy_nodes(_M_start._M_node, _M_finish._M_node + 1);
414 _M_deallocate_map(this->_M_map, this->_M_map_size);
420 * @brief Layout storage.
421 * @param num_elements The count of T's for which to allocate space
425 * The initial underlying memory layout is a bit complicated...
428 template<typename _Tp, typename _Alloc>
430 _Deque_base<_Tp,_Alloc>::_M_initialize_map(size_t __num_elements)
432 size_t __num_nodes = __num_elements / __deque_buf_size(sizeof(_Tp)) + 1;
434 this->_M_map_size = std::max((size_t) _S_initial_map_size,
436 this->_M_map = _M_allocate_map(this->_M_map_size);
438 // For "small" maps (needing less than _M_map_size nodes), allocation
439 // starts in the middle elements and grows outwards. So nstart may be
440 // the beginning of _M_map, but for small maps it may be as far in as
443 _Tp** __nstart = this->_M_map + (this->_M_map_size - __num_nodes) / 2;
444 _Tp** __nfinish = __nstart + __num_nodes;
447 { _M_create_nodes(__nstart, __nfinish); }
450 _M_deallocate_map(this->_M_map, this->_M_map_size);
452 this->_M_map_size = 0;
453 __throw_exception_again;
456 _M_start._M_set_node(__nstart);
457 _M_finish._M_set_node(__nfinish - 1);
458 _M_start._M_cur = _M_start._M_first;
459 _M_finish._M_cur = _M_finish._M_first + __num_elements
460 % __deque_buf_size(sizeof(_Tp));
463 template<typename _Tp, typename _Alloc>
465 _Deque_base<_Tp,_Alloc>::_M_create_nodes(_Tp** __nstart, _Tp** __nfinish)
470 for (__cur = __nstart; __cur < __nfinish; ++__cur)
471 *__cur = this->_M_allocate_node();
475 _M_destroy_nodes(__nstart, __cur);
476 __throw_exception_again;
480 template<typename _Tp, typename _Alloc>
482 _Deque_base<_Tp,_Alloc>::_M_destroy_nodes(_Tp** __nstart, _Tp** __nfinish)
484 for (_Tp** __n = __nstart; __n < __nfinish; ++__n)
485 _M_deallocate_node(*__n);
489 * @brief A standard container using fixed-size memory allocation and
490 * constant-time manipulation of elements at either end.
492 * @ingroup Containers
495 * Meets the requirements of a <a href="tables.html#65">container</a>, a
496 * <a href="tables.html#66">reversible container</a>, and a
497 * <a href="tables.html#67">sequence</a>, including the
498 * <a href="tables.html#68">optional sequence requirements</a>.
500 * In previous HP/SGI versions of deque, there was an extra template
501 * parameter so users could control the node size. This extension turned
502 * out to violate the C++ standard (it can be detected using template
503 * template parameters), and it was removed.
506 * Here's how a deque<Tp> manages memory. Each deque has 4 members:
509 * - size_t _M_map_size
510 * - iterator _M_start, _M_finish
512 * map_size is at least 8. %map is an array of map_size pointers-to-"nodes".
513 * (The name %map has nothing to do with the std::map class, and "nodes"
514 * should not be confused with std::list's usage of "node".)
516 * A "node" has no specific type name as such, but it is referred to as
517 * "node" in this file. It is a simple array-of-Tp. If Tp is very large,
518 * there will be one Tp element per node (i.e., an "array" of one).
519 * For non-huge Tp's, node size is inversely related to Tp size: the
520 * larger the Tp, the fewer Tp's will fit in a node. The goal here is to
521 * keep the total size of a node relatively small and constant over different
522 * Tp's, to improve allocator efficiency.
524 * **** As I write this, the nodes are /not/ allocated using the high-speed
525 * memory pool. There are 20 hours left in the year; perhaps I can fix
528 * Not every pointer in the %map array will point to a node. If the initial
529 * number of elements in the deque is small, the /middle/ %map pointers will
530 * be valid, and the ones at the edges will be unused. This same situation
531 * will arise as the %map grows: available %map pointers, if any, will be on
532 * the ends. As new nodes are created, only a subset of the %map's pointers
533 * need to be copied "outward".
536 * - For any nonsingular iterator i:
537 * - i.node points to a member of the %map array. (Yes, you read that
538 * correctly: i.node does not actually point to a node.) The member of
539 * the %map array is what actually points to the node.
540 * - i.first == *(i.node) (This points to the node (first Tp element).)
541 * - i.last == i.first + node_size
542 * - i.cur is a pointer in the range [i.first, i.last). NOTE:
543 * the implication of this is that i.cur is always a dereferenceable
544 * pointer, even if i is a past-the-end iterator.
545 * - Start and Finish are always nonsingular iterators. NOTE: this means that
546 * an empty deque must have one node, a deque with <N elements (where N is
547 * the node buffer size) must have one node, a deque with N through (2N-1)
548 * elements must have two nodes, etc.
549 * - For every node other than start.node and finish.node, every element in
550 * the node is an initialized object. If start.node == finish.node, then
551 * [start.cur, finish.cur) are initialized objects, and the elements outside
552 * that range are uninitialized storage. Otherwise, [start.cur, start.last)
553 * and [finish.first, finish.cur) are initialized objects, and [start.first,
554 * start.cur) and [finish.cur, finish.last) are uninitialized storage.
555 * - [%map, %map + map_size) is a valid, non-empty range.
556 * - [start.node, finish.node] is a valid range contained within
557 * [%map, %map + map_size).
558 * - A pointer in the range [%map, %map + map_size) points to an allocated
559 * node if and only if the pointer is in the range
560 * [start.node, finish.node].
562 * Here's the magic: nothing in deque is "aware" of the discontiguous
565 * The memory setup and layout occurs in the parent, _Base, and the iterator
566 * class is entirely responsible for "leaping" from one node to the next.
567 * All the implementation routines for deque itself work only through the
568 * start and finish iterators. This keeps the routines simple and sane,
569 * and we can use other standard algorithms as well.
572 template<typename _Tp, typename _Alloc = allocator<_Tp> >
573 class deque : protected _Deque_base<_Tp, _Alloc>
575 // concept requirements
576 __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
578 typedef _Deque_base<_Tp, _Alloc> _Base;
581 typedef _Tp value_type;
582 typedef value_type* pointer;
583 typedef const value_type* const_pointer;
584 typedef typename _Base::iterator iterator;
585 typedef typename _Base::const_iterator const_iterator;
586 typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
587 typedef std::reverse_iterator<iterator> reverse_iterator;
588 typedef value_type& reference;
589 typedef const value_type& const_reference;
590 typedef size_t size_type;
591 typedef ptrdiff_t difference_type;
592 typedef typename _Base::allocator_type allocator_type;
595 typedef pointer* _Map_pointer;
597 static size_t _S_buffer_size()
598 { return __deque_buf_size(sizeof(_Tp)); }
600 // Functions controlling memory layout, and nothing else.
601 using _Base::_M_initialize_map;
602 using _Base::_M_create_nodes;
603 using _Base::_M_destroy_nodes;
604 using _Base::_M_allocate_node;
605 using _Base::_M_deallocate_node;
606 using _Base::_M_allocate_map;
607 using _Base::_M_deallocate_map;
610 * A total of four data members accumulated down the heirarchy.
614 using _Base::_M_map_size;
615 using _Base::_M_start;
616 using _Base::_M_finish;
619 // [23.2.1.1] construct/copy/destroy
620 // (assign() and get_allocator() are also listed in this section)
622 * @brief Default constructor creates no elements.
625 deque(const allocator_type& __a = allocator_type())
629 * @brief Create a %deque with copies of an exemplar element.
630 * @param n The number of elements to initially create.
631 * @param value An element to copy.
633 * This constructor fills the %deque with @a n copies of @a value.
635 deque(size_type __n, const value_type& __value,
636 const allocator_type& __a = allocator_type())
638 { _M_fill_initialize(__value); }
641 * @brief Create a %deque with default elements.
642 * @param n The number of elements to initially create.
644 * This constructor fills the %deque with @a n copies of a
645 * default-constructed element.
649 : _Base(allocator_type(), __n)
650 { _M_fill_initialize(value_type()); }
653 * @brief %Deque copy constructor.
654 * @param x A %deque of identical element and allocator types.
656 * The newly-created %deque uses a copy of the allocation object used
659 deque(const deque& __x)
660 : _Base(__x.get_allocator(), __x.size())
661 { std::uninitialized_copy(__x.begin(), __x.end(), this->_M_start); }
664 * @brief Builds a %deque from a range.
665 * @param first An input iterator.
666 * @param last An input iterator.
668 * Create a %deque consisting of copies of the elements from [first,
671 * If the iterators are forward, bidirectional, or random-access, then
672 * this will call the elements' copy constructor N times (where N is
673 * distance(first,last)) and do no memory reallocation. But if only
674 * input iterators are used, then this will do at most 2N calls to the
675 * copy constructor, and logN memory reallocations.
677 template<typename _InputIterator>
678 deque(_InputIterator __first, _InputIterator __last,
679 const allocator_type& __a = allocator_type())
682 // Check whether it's an integral type. If so, it's not an iterator.
683 typedef typename _Is_integer<_InputIterator>::_Integral _Integral;
684 _M_initialize_dispatch(__first, __last, _Integral());
688 * The dtor only erases the elements, and note that if the elements
689 * themselves are pointers, the pointed-to memory is not touched in any
690 * way. Managing the pointer is the user's responsibilty.
693 { std::_Destroy(this->_M_start, this->_M_finish); }
696 * @brief %Deque assignment operator.
697 * @param x A %deque of identical element and allocator types.
699 * All the elements of @a x are copied, but unlike the copy constructor,
700 * the allocator object is not copied.
703 operator=(const deque& __x);
706 * @brief Assigns a given value to a %deque.
707 * @param n Number of elements to be assigned.
708 * @param val Value to be assigned.
710 * This function fills a %deque with @a n copies of the given value.
711 * Note that the assignment completely changes the %deque and that the
712 * resulting %deque's size is the same as the number of elements assigned.
713 * Old data may be lost.
716 assign(size_type __n, const value_type& __val)
717 { _M_fill_assign(__n, __val); }
720 * @brief Assigns a range to a %deque.
721 * @param first An input iterator.
722 * @param last An input iterator.
724 * This function fills a %deque with copies of the elements in the
725 * range [first,last).
727 * Note that the assignment completely changes the %deque and that the
728 * resulting %deque's size is the same as the number of elements
729 * assigned. Old data may be lost.
731 template<typename _InputIterator>
733 assign(_InputIterator __first, _InputIterator __last)
735 typedef typename _Is_integer<_InputIterator>::_Integral _Integral;
736 _M_assign_dispatch(__first, __last, _Integral());
739 /// Get a copy of the memory allocation object.
741 get_allocator() const
742 { return _Base::get_allocator(); }
746 * Returns a read/write iterator that points to the first element in the
747 * %deque. Iteration is done in ordinary element order.
751 { return this->_M_start; }
754 * Returns a read-only (constant) iterator that points to the first
755 * element in the %deque. Iteration is done in ordinary element order.
759 { return this->_M_start; }
762 * Returns a read/write iterator that points one past the last element in
763 * the %deque. Iteration is done in ordinary element order.
767 { return this->_M_finish; }
770 * Returns a read-only (constant) iterator that points one past the last
771 * element in the %deque. Iteration is done in ordinary element order.
775 { return this->_M_finish; }
778 * Returns a read/write reverse iterator that points to the last element
779 * in the %deque. Iteration is done in reverse element order.
783 { return reverse_iterator(this->_M_finish); }
786 * Returns a read-only (constant) reverse iterator that points to the
787 * last element in the %deque. Iteration is done in reverse element
790 const_reverse_iterator
792 { return const_reverse_iterator(this->_M_finish); }
795 * Returns a read/write reverse iterator that points to one before the
796 * first element in the %deque. Iteration is done in reverse element
800 rend() { return reverse_iterator(this->_M_start); }
803 * Returns a read-only (constant) reverse iterator that points to one
804 * before the first element in the %deque. Iteration is done in reverse
807 const_reverse_iterator
809 { return const_reverse_iterator(this->_M_start); }
811 // [23.2.1.2] capacity
812 /** Returns the number of elements in the %deque. */
815 { return this->_M_finish - this->_M_start; }
817 /** Returns the size() of the largest possible %deque. */
820 { return size_type(-1); }
823 * @brief Resizes the %deque to the specified number of elements.
824 * @param new_size Number of elements the %deque should contain.
825 * @param x Data with which new elements should be populated.
827 * This function will %resize the %deque to the specified number of
828 * elements. If the number is smaller than the %deque's current size the
829 * %deque is truncated, otherwise the %deque is extended and new elements
830 * are populated with given data.
833 resize(size_type __new_size, const value_type& __x)
835 const size_type __len = size();
836 if (__new_size < __len)
837 erase(this->_M_start + __new_size, this->_M_finish);
839 insert(this->_M_finish, __new_size - __len, __x);
843 * @brief Resizes the %deque to the specified number of elements.
844 * @param new_size Number of elements the %deque should contain.
846 * This function will resize the %deque to the specified number of
847 * elements. If the number is smaller than the %deque's current size the
848 * %deque is truncated, otherwise the %deque is extended and new elements
849 * are default-constructed.
852 resize(size_type new_size)
853 { resize(new_size, value_type()); }
856 * Returns true if the %deque is empty. (Thus begin() would equal end().)
860 { return this->_M_finish == this->_M_start; }
864 * @brief Subscript access to the data contained in the %deque.
865 * @param n The index of the element for which data should be accessed.
866 * @return Read/write reference to data.
868 * This operator allows for easy, array-style, data access.
869 * Note that data access with this operator is unchecked and out_of_range
870 * lookups are not defined. (For checked lookups see at().)
873 operator[](size_type __n)
874 { return this->_M_start[difference_type(__n)]; }
877 * @brief Subscript access to the data contained in the %deque.
878 * @param n The index of the element for which data should be accessed.
879 * @return Read-only (constant) reference to data.
881 * This operator allows for easy, array-style, data access.
882 * Note that data access with this operator is unchecked and out_of_range
883 * lookups are not defined. (For checked lookups see at().)
886 operator[](size_type __n) const
887 { return this->_M_start[difference_type(__n)]; }
890 /// @if maint Safety check used only from at(). @endif
892 _M_range_check(size_type __n) const
894 if (__n >= this->size())
895 __throw_out_of_range(__N("deque::_M_range_check"));
900 * @brief Provides access to the data contained in the %deque.
901 * @param n The index of the element for which data should be accessed.
902 * @return Read/write reference to data.
903 * @throw std::out_of_range If @a n is an invalid index.
905 * This function provides for safer data access. The parameter is first
906 * checked that it is in the range of the deque. The function throws
907 * out_of_range if the check fails.
911 { _M_range_check(__n); return (*this)[__n]; }
914 * @brief Provides access to the data contained in the %deque.
915 * @param n The index of the element for which data should be accessed.
916 * @return Read-only (constant) reference to data.
917 * @throw std::out_of_range If @a n is an invalid index.
919 * This function provides for safer data access. The parameter is first
920 * checked that it is in the range of the deque. The function throws
921 * out_of_range if the check fails.
924 at(size_type __n) const
931 * Returns a read/write reference to the data at the first element of the
936 { return *this->_M_start; }
939 * Returns a read-only (constant) reference to the data at the first
940 * element of the %deque.
944 { return *this->_M_start; }
947 * Returns a read/write reference to the data at the last element of the
953 iterator __tmp = this->_M_finish;
959 * Returns a read-only (constant) reference to the data at the last
960 * element of the %deque.
965 const_iterator __tmp = this->_M_finish;
970 // [23.2.1.2] modifiers
972 * @brief Add data to the front of the %deque.
973 * @param x Data to be added.
975 * This is a typical stack operation. The function creates an element at
976 * the front of the %deque and assigns the given data to it. Due to the
977 * nature of a %deque this operation can be done in constant time.
980 push_front(const value_type& __x)
982 if (this->_M_start._M_cur != this->_M_start._M_first)
984 std::_Construct(this->_M_start._M_cur - 1, __x);
985 --this->_M_start._M_cur;
988 _M_push_front_aux(__x);
992 * @brief Add data to the end of the %deque.
993 * @param x Data to be added.
995 * This is a typical stack operation. The function creates an element at
996 * the end of the %deque and assigns the given data to it. Due to the
997 * nature of a %deque this operation can be done in constant time.
1000 push_back(const value_type& __x)
1002 if (this->_M_finish._M_cur != this->_M_finish._M_last - 1)
1004 std::_Construct(this->_M_finish._M_cur, __x);
1005 ++this->_M_finish._M_cur;
1008 _M_push_back_aux(__x);
1012 * @brief Removes first element.
1014 * This is a typical stack operation. It shrinks the %deque by one.
1016 * Note that no data is returned, and if the first element's data is
1017 * needed, it should be retrieved before pop_front() is called.
1022 if (this->_M_start._M_cur != this->_M_start._M_last - 1)
1024 std::_Destroy(this->_M_start._M_cur);
1025 ++this->_M_start._M_cur;
1032 * @brief Removes last element.
1034 * This is a typical stack operation. It shrinks the %deque by one.
1036 * Note that no data is returned, and if the last element's data is
1037 * needed, it should be retrieved before pop_back() is called.
1042 if (this->_M_finish._M_cur != this->_M_finish._M_first)
1044 --this->_M_finish._M_cur;
1045 std::_Destroy(this->_M_finish._M_cur);
1052 * @brief Inserts given value into %deque before specified iterator.
1053 * @param position An iterator into the %deque.
1054 * @param x Data to be inserted.
1055 * @return An iterator that points to the inserted data.
1057 * This function will insert a copy of the given value before the
1058 * specified location.
1061 insert(iterator position, const value_type& __x);
1064 * @brief Inserts a number of copies of given data into the %deque.
1065 * @param position An iterator into the %deque.
1066 * @param n Number of elements to be inserted.
1067 * @param x Data to be inserted.
1069 * This function will insert a specified number of copies of the given
1070 * data before the location specified by @a position.
1073 insert(iterator __position, size_type __n, const value_type& __x)
1074 { _M_fill_insert(__position, __n, __x); }
1077 * @brief Inserts a range into the %deque.
1078 * @param position An iterator into the %deque.
1079 * @param first An input iterator.
1080 * @param last An input iterator.
1082 * This function will insert copies of the data in the range [first,last)
1083 * into the %deque before the location specified by @a pos. This is
1084 * known as "range insert."
1086 template<typename _InputIterator>
1088 insert(iterator __position, _InputIterator __first,
1089 _InputIterator __last)
1091 // Check whether it's an integral type. If so, it's not an iterator.
1092 typedef typename _Is_integer<_InputIterator>::_Integral _Integral;
1093 _M_insert_dispatch(__position, __first, __last, _Integral());
1097 * @brief Remove element at given position.
1098 * @param position Iterator pointing to element to be erased.
1099 * @return An iterator pointing to the next element (or end()).
1101 * This function will erase the element at the given position and thus
1102 * shorten the %deque by one.
1104 * The user is cautioned that
1105 * this function only erases the element, and that if the element is
1106 * itself a pointer, the pointed-to memory is not touched in any way.
1107 * Managing the pointer is the user's responsibilty.
1110 erase(iterator __position);
1113 * @brief Remove a range of elements.
1114 * @param first Iterator pointing to the first element to be erased.
1115 * @param last Iterator pointing to one past the last element to be
1117 * @return An iterator pointing to the element pointed to by @a last
1118 * prior to erasing (or end()).
1120 * This function will erase the elements in the range [first,last) and
1121 * shorten the %deque accordingly.
1123 * The user is cautioned that
1124 * this function only erases the elements, and that if the elements
1125 * themselves are pointers, the pointed-to memory is not touched in any
1126 * way. Managing the pointer is the user's responsibilty.
1129 erase(iterator __first, iterator __last);
1132 * @brief Swaps data with another %deque.
1133 * @param x A %deque of the same element and allocator types.
1135 * This exchanges the elements between two deques in constant time.
1136 * (Four pointers, so it should be quite fast.)
1137 * Note that the global std::swap() function is specialized such that
1138 * std::swap(d1,d2) will feed to this function.
1143 std::swap(this->_M_start, __x._M_start);
1144 std::swap(this->_M_finish, __x._M_finish);
1145 std::swap(this->_M_map, __x._M_map);
1146 std::swap(this->_M_map_size, __x._M_map_size);
1150 * Erases all the elements. Note that this function only erases the
1151 * elements, and that if the elements themselves are pointers, the
1152 * pointed-to memory is not touched in any way. Managing the pointer is
1153 * the user's responsibilty.
1158 // Internal constructor functions follow.
1160 // called by the range constructor to implement [23.1.1]/9
1161 template<typename _Integer>
1163 _M_initialize_dispatch(_Integer __n, _Integer __x, __true_type)
1165 _M_initialize_map(__n);
1166 _M_fill_initialize(__x);
1169 // called by the range constructor to implement [23.1.1]/9
1170 template<typename _InputIterator>
1172 _M_initialize_dispatch(_InputIterator __first, _InputIterator __last,
1175 typedef typename iterator_traits<_InputIterator>::iterator_category
1177 _M_range_initialize(__first, __last, _IterCategory());
1180 // called by the second initialize_dispatch above
1184 * @brief Fills the deque with whatever is in [first,last).
1185 * @param first An input iterator.
1186 * @param last An input iterator.
1189 * If the iterators are actually forward iterators (or better), then the
1190 * memory layout can be done all at once. Else we move forward using
1191 * push_back on each value from the iterator.
1194 template<typename _InputIterator>
1196 _M_range_initialize(_InputIterator __first, _InputIterator __last,
1197 input_iterator_tag);
1199 // called by the second initialize_dispatch above
1200 template<typename _ForwardIterator>
1202 _M_range_initialize(_ForwardIterator __first, _ForwardIterator __last,
1203 forward_iterator_tag);
1208 * @brief Fills the %deque with copies of value.
1209 * @param value Initial value.
1211 * @pre _M_start and _M_finish have already been initialized, but none of
1212 * the %deque's elements have yet been constructed.
1214 * This function is called only when the user provides an explicit size
1215 * (with or without an explicit exemplar value).
1219 _M_fill_initialize(const value_type& __value);
1221 // Internal assign functions follow. The *_aux functions do the actual
1222 // assignment work for the range versions.
1224 // called by the range assign to implement [23.1.1]/9
1225 template<typename _Integer>
1227 _M_assign_dispatch(_Integer __n, _Integer __val, __true_type)
1229 _M_fill_assign(static_cast<size_type>(__n),
1230 static_cast<value_type>(__val));
1233 // called by the range assign to implement [23.1.1]/9
1234 template<typename _InputIterator>
1236 _M_assign_dispatch(_InputIterator __first, _InputIterator __last,
1239 typedef typename iterator_traits<_InputIterator>::iterator_category
1241 _M_assign_aux(__first, __last, _IterCategory());
1244 // called by the second assign_dispatch above
1245 template<typename _InputIterator>
1247 _M_assign_aux(_InputIterator __first, _InputIterator __last,
1248 input_iterator_tag);
1250 // called by the second assign_dispatch above
1251 template<typename _ForwardIterator>
1253 _M_assign_aux(_ForwardIterator __first, _ForwardIterator __last,
1254 forward_iterator_tag)
1256 const size_type __len = std::distance(__first, __last);
1259 _ForwardIterator __mid = __first;
1260 std::advance(__mid, size());
1261 std::copy(__first, __mid, begin());
1262 insert(end(), __mid, __last);
1265 erase(std::copy(__first, __last, begin()), end());
1268 // Called by assign(n,t), and the range assign when it turns out to be the
1271 _M_fill_assign(size_type __n, const value_type& __val)
1275 std::fill(begin(), end(), __val);
1276 insert(end(), __n - size(), __val);
1280 erase(begin() + __n, end());
1281 std::fill(begin(), end(), __val);
1288 * @brief Helper functions for push_* and pop_*.
1291 void _M_push_back_aux(const value_type&);
1292 void _M_push_front_aux(const value_type&);
1293 void _M_pop_back_aux();
1294 void _M_pop_front_aux();
1297 // Internal insert functions follow. The *_aux functions do the actual
1298 // insertion work when all shortcuts fail.
1300 // called by the range insert to implement [23.1.1]/9
1301 template<typename _Integer>
1303 _M_insert_dispatch(iterator __pos,
1304 _Integer __n, _Integer __x, __true_type)
1306 _M_fill_insert(__pos, static_cast<size_type>(__n),
1307 static_cast<value_type>(__x));
1310 // called by the range insert to implement [23.1.1]/9
1311 template<typename _InputIterator>
1313 _M_insert_dispatch(iterator __pos,
1314 _InputIterator __first, _InputIterator __last,
1317 typedef typename iterator_traits<_InputIterator>::iterator_category
1319 _M_range_insert_aux(__pos, __first, __last, _IterCategory());
1322 // called by the second insert_dispatch above
1323 template<typename _InputIterator>
1325 _M_range_insert_aux(iterator __pos, _InputIterator __first,
1326 _InputIterator __last, input_iterator_tag);
1328 // called by the second insert_dispatch above
1329 template<typename _ForwardIterator>
1331 _M_range_insert_aux(iterator __pos, _ForwardIterator __first,
1332 _ForwardIterator __last, forward_iterator_tag);
1334 // Called by insert(p,n,x), and the range insert when it turns out to be
1335 // the same thing. Can use fill functions in optimal situations,
1336 // otherwise passes off to insert_aux(p,n,x).
1338 _M_fill_insert(iterator __pos, size_type __n, const value_type& __x);
1340 // called by insert(p,x)
1342 _M_insert_aux(iterator __pos, const value_type& __x);
1344 // called by insert(p,n,x) via fill_insert
1346 _M_insert_aux(iterator __pos, size_type __n, const value_type& __x);
1348 // called by range_insert_aux for forward iterators
1349 template<typename _ForwardIterator>
1351 _M_insert_aux(iterator __pos,
1352 _ForwardIterator __first, _ForwardIterator __last,
1358 * @brief Memory-handling helpers for the previous internal insert
1363 _M_reserve_elements_at_front(size_type __n)
1365 const size_type __vacancies = this->_M_start._M_cur
1366 - this->_M_start._M_first;
1367 if (__n > __vacancies)
1368 _M_new_elements_at_front(__n - __vacancies);
1369 return this->_M_start - difference_type(__n);
1373 _M_reserve_elements_at_back(size_type __n)
1375 const size_type __vacancies = (this->_M_finish._M_last
1376 - this->_M_finish._M_cur) - 1;
1377 if (__n > __vacancies)
1378 _M_new_elements_at_back(__n - __vacancies);
1379 return this->_M_finish + difference_type(__n);
1383 _M_new_elements_at_front(size_type __new_elements);
1386 _M_new_elements_at_back(size_type __new_elements);
1393 * @brief Memory-handling helpers for the major %map.
1395 * Makes sure the _M_map has space for new nodes. Does not actually add
1396 * the nodes. Can invalidate _M_map pointers. (And consequently, %deque
1401 _M_reserve_map_at_back (size_type __nodes_to_add = 1)
1403 if (__nodes_to_add + 1 > this->_M_map_size
1404 - (this->_M_finish._M_node - this->_M_map))
1405 _M_reallocate_map(__nodes_to_add, false);
1409 _M_reserve_map_at_front (size_type __nodes_to_add = 1)
1411 if (__nodes_to_add > size_type(this->_M_start._M_node - this->_M_map))
1412 _M_reallocate_map(__nodes_to_add, true);
1416 _M_reallocate_map(size_type __nodes_to_add, bool __add_at_front);
1422 * @brief Deque equality comparison.
1423 * @param x A %deque.
1424 * @param y A %deque of the same type as @a x.
1425 * @return True iff the size and elements of the deques are equal.
1427 * This is an equivalence relation. It is linear in the size of the
1428 * deques. Deques are considered equivalent if their sizes are equal,
1429 * and if corresponding elements compare equal.
1431 template<typename _Tp, typename _Alloc>
1433 operator==(const deque<_Tp, _Alloc>& __x,
1434 const deque<_Tp, _Alloc>& __y)
1435 { return __x.size() == __y.size()
1436 && std::equal(__x.begin(), __x.end(), __y.begin()); }
1439 * @brief Deque ordering relation.
1440 * @param x A %deque.
1441 * @param y A %deque of the same type as @a x.
1442 * @return True iff @a x is lexicographically less than @a y.
1444 * This is a total ordering relation. It is linear in the size of the
1445 * deques. The elements must be comparable with @c <.
1447 * See std::lexicographical_compare() for how the determination is made.
1449 template<typename _Tp, typename _Alloc>
1451 operator<(const deque<_Tp, _Alloc>& __x,
1452 const deque<_Tp, _Alloc>& __y)
1453 { return lexicographical_compare(__x.begin(), __x.end(),
1454 __y.begin(), __y.end()); }
1456 /// Based on operator==
1457 template<typename _Tp, typename _Alloc>
1459 operator!=(const deque<_Tp, _Alloc>& __x,
1460 const deque<_Tp, _Alloc>& __y)
1461 { return !(__x == __y); }
1463 /// Based on operator<
1464 template<typename _Tp, typename _Alloc>
1466 operator>(const deque<_Tp, _Alloc>& __x,
1467 const deque<_Tp, _Alloc>& __y)
1468 { return __y < __x; }
1470 /// Based on operator<
1471 template<typename _Tp, typename _Alloc>
1473 operator<=(const deque<_Tp, _Alloc>& __x,
1474 const deque<_Tp, _Alloc>& __y)
1475 { return !(__y < __x); }
1477 /// Based on operator<
1478 template<typename _Tp, typename _Alloc>
1480 operator>=(const deque<_Tp, _Alloc>& __x,
1481 const deque<_Tp, _Alloc>& __y)
1482 { return !(__x < __y); }
1484 /// See std::deque::swap().
1485 template<typename _Tp, typename _Alloc>
1487 swap(deque<_Tp,_Alloc>& __x, deque<_Tp,_Alloc>& __y)
1489 } // namespace __gnu_norm
1491 #endif /* _DEQUE_H */