1 // Queue implementation -*- C++ -*-
3 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009,
5 // Free Software Foundation, Inc.
7 // This file is part of the GNU ISO C++ Library. This library is free
8 // software; you can redistribute it and/or modify it under the
9 // terms of the GNU General Public License as published by the
10 // Free Software Foundation; either version 3, or (at your option)
13 // This library is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
18 // Under Section 7 of GPL version 3, you are granted additional
19 // permissions described in the GCC Runtime Library Exception, version
20 // 3.1, as published by the Free Software Foundation.
22 // You should have received a copy of the GNU General Public License and
23 // a copy of the GCC Runtime Library Exception along with this program;
24 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
25 // <http://www.gnu.org/licenses/>.
30 * Hewlett-Packard Company
32 * Permission to use, copy, modify, distribute and sell this software
33 * and its documentation for any purpose is hereby granted without fee,
34 * provided that the above copyright notice appear in all copies and
35 * that both that copyright notice and this permission notice appear
36 * in supporting documentation. Hewlett-Packard Company makes no
37 * representations about the suitability of this software for any
38 * purpose. It is provided "as is" without express or implied warranty.
41 * Copyright (c) 1996,1997
42 * Silicon Graphics Computer Systems, Inc.
44 * Permission to use, copy, modify, distribute and sell this software
45 * and its documentation for any purpose is hereby granted without fee,
46 * provided that the above copyright notice appear in all copies and
47 * that both that copyright notice and this permission notice appear
48 * in supporting documentation. Silicon Graphics makes no
49 * representations about the suitability of this software for any
50 * purpose. It is provided "as is" without express or implied warranty.
53 /** @file bits/stl_queue.h
54 * This is an internal header file, included by other library headers.
55 * Do not attempt to use it directly. @headername{queue}
59 #define _STL_QUEUE_H 1
61 #include <bits/concept_check.h>
62 #include <debug/debug.h>
64 namespace std _GLIBCXX_VISIBILITY(default)
66 _GLIBCXX_BEGIN_NAMESPACE_VERSION
69 * @brief A standard container giving FIFO behavior.
73 * Meets many of the requirements of a
74 * <a href="tables.html#65">container</a>,
75 * but does not define anything to do with iterators. Very few of the
76 * other standard container interfaces are defined.
78 * This is not a true container, but an @e adaptor. It holds another
79 * container, and provides a wrapper interface to that container. The
80 * wrapper is what enforces strict first-in-first-out %queue behavior.
82 * The second template parameter defines the type of the underlying
83 * sequence/container. It defaults to std::deque, but it can be any type
84 * that supports @c front, @c back, @c push_back, and @c pop_front,
85 * such as std::list or an appropriate user-defined type.
87 * Members not found in @a normal containers are @c container_type,
88 * which is a typedef for the second Sequence parameter, and @c push and
89 * @c pop, which are standard %queue/FIFO operations.
91 template<typename _Tp, typename _Sequence = deque<_Tp> >
94 // concept requirements
95 typedef typename _Sequence::value_type _Sequence_value_type;
96 __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
97 __glibcxx_class_requires(_Sequence, _FrontInsertionSequenceConcept)
98 __glibcxx_class_requires(_Sequence, _BackInsertionSequenceConcept)
99 __glibcxx_class_requires2(_Tp, _Sequence_value_type, _SameTypeConcept)
101 template<typename _Tp1, typename _Seq1>
103 operator==(const queue<_Tp1, _Seq1>&, const queue<_Tp1, _Seq1>&);
105 template<typename _Tp1, typename _Seq1>
107 operator<(const queue<_Tp1, _Seq1>&, const queue<_Tp1, _Seq1>&);
110 typedef typename _Sequence::value_type value_type;
111 typedef typename _Sequence::reference reference;
112 typedef typename _Sequence::const_reference const_reference;
113 typedef typename _Sequence::size_type size_type;
114 typedef _Sequence container_type;
118 * 'c' is the underlying container. Maintainers wondering why
119 * this isn't uglified as per style guidelines should note that
120 * this name is specified in the standard, [23.2.3.1]. (Why?
121 * Presumably for the same reason that it's protected instead
122 * of private: to allow derivation. But none of the other
123 * containers allow for derivation. Odd.)
129 * @brief Default constructor creates no elements.
131 #ifndef __GXX_EXPERIMENTAL_CXX0X__
133 queue(const _Sequence& __c = _Sequence())
137 queue(const _Sequence& __c)
141 queue(_Sequence&& __c = _Sequence())
142 : c(std::move(__c)) { }
146 * Returns true if the %queue is empty.
150 { return c.empty(); }
152 /** Returns the number of elements in the %queue. */
158 * Returns a read/write reference to the data at the first
159 * element of the %queue.
164 __glibcxx_requires_nonempty();
169 * Returns a read-only (constant) reference to the data at the first
170 * element of the %queue.
175 __glibcxx_requires_nonempty();
180 * Returns a read/write reference to the data at the last
181 * element of the %queue.
186 __glibcxx_requires_nonempty();
191 * Returns a read-only (constant) reference to the data at the last
192 * element of the %queue.
197 __glibcxx_requires_nonempty();
202 * @brief Add data to the end of the %queue.
203 * @param x Data to be added.
205 * This is a typical %queue operation. The function creates an
206 * element at the end of the %queue and assigns the given data
207 * to it. The time complexity of the operation depends on the
208 * underlying sequence.
211 push(const value_type& __x)
212 { c.push_back(__x); }
214 #ifdef __GXX_EXPERIMENTAL_CXX0X__
216 push(value_type&& __x)
217 { c.push_back(std::move(__x)); }
219 template<typename... _Args>
221 emplace(_Args&&... __args)
222 { c.emplace_back(std::forward<_Args>(__args)...); }
226 * @brief Removes first element.
228 * This is a typical %queue operation. It shrinks the %queue by one.
229 * The time complexity of the operation depends on the underlying
232 * Note that no data is returned, and if the first element's
233 * data is needed, it should be retrieved before pop() is
239 __glibcxx_requires_nonempty();
243 #ifdef __GXX_EXPERIMENTAL_CXX0X__
254 * @brief Queue equality comparison.
256 * @param y A %queue of the same type as @a x.
257 * @return True iff the size and elements of the queues are equal.
259 * This is an equivalence relation. Complexity and semantics depend on the
260 * underlying sequence type, but the expected rules are: this relation is
261 * linear in the size of the sequences, and queues are considered equivalent
262 * if their sequences compare equal.
264 template<typename _Tp, typename _Seq>
266 operator==(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
267 { return __x.c == __y.c; }
270 * @brief Queue ordering relation.
272 * @param y A %queue of the same type as @a x.
273 * @return True iff @a x is lexicographically less than @a y.
275 * This is an total ordering relation. Complexity and semantics
276 * depend on the underlying sequence type, but the expected rules
277 * are: this relation is linear in the size of the sequences, the
278 * elements must be comparable with @c <, and
279 * std::lexicographical_compare() is usually used to make the
282 template<typename _Tp, typename _Seq>
284 operator<(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
285 { return __x.c < __y.c; }
287 /// Based on operator==
288 template<typename _Tp, typename _Seq>
290 operator!=(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
291 { return !(__x == __y); }
293 /// Based on operator<
294 template<typename _Tp, typename _Seq>
296 operator>(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
297 { return __y < __x; }
299 /// Based on operator<
300 template<typename _Tp, typename _Seq>
302 operator<=(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
303 { return !(__y < __x); }
305 /// Based on operator<
306 template<typename _Tp, typename _Seq>
308 operator>=(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
309 { return !(__x < __y); }
311 #ifdef __GXX_EXPERIMENTAL_CXX0X__
312 template<typename _Tp, typename _Seq>
314 swap(queue<_Tp, _Seq>& __x, queue<_Tp, _Seq>& __y)
317 template<typename _Tp, typename _Seq, typename _Alloc>
318 struct uses_allocator<queue<_Tp, _Seq>, _Alloc>
319 : public uses_allocator<_Seq, _Alloc>::type { };
323 * @brief A standard container automatically sorting its contents.
327 * This is not a true container, but an @e adaptor. It holds
328 * another container, and provides a wrapper interface to that
329 * container. The wrapper is what enforces priority-based sorting
330 * and %queue behavior. Very few of the standard container/sequence
331 * interface requirements are met (e.g., iterators).
333 * The second template parameter defines the type of the underlying
334 * sequence/container. It defaults to std::vector, but it can be
335 * any type that supports @c front(), @c push_back, @c pop_back,
336 * and random-access iterators, such as std::deque or an
337 * appropriate user-defined type.
339 * The third template parameter supplies the means of making
340 * priority comparisons. It defaults to @c less<value_type> but
341 * can be anything defining a strict weak ordering.
343 * Members not found in @a normal containers are @c container_type,
344 * which is a typedef for the second Sequence parameter, and @c
345 * push, @c pop, and @c top, which are standard %queue operations.
347 * @note No equality/comparison operators are provided for
350 * @note Sorting of the elements takes place as they are added to,
351 * and removed from, the %priority_queue using the
352 * %priority_queue's member functions. If you access the elements
353 * by other means, and change their data such that the sorting
354 * order would be different, the %priority_queue will not re-sort
355 * the elements for you. (How could it know to do so?)
357 template<typename _Tp, typename _Sequence = vector<_Tp>,
358 typename _Compare = less<typename _Sequence::value_type> >
361 // concept requirements
362 typedef typename _Sequence::value_type _Sequence_value_type;
363 __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
364 __glibcxx_class_requires(_Sequence, _SequenceConcept)
365 __glibcxx_class_requires(_Sequence, _RandomAccessContainerConcept)
366 __glibcxx_class_requires2(_Tp, _Sequence_value_type, _SameTypeConcept)
367 __glibcxx_class_requires4(_Compare, bool, _Tp, _Tp,
368 _BinaryFunctionConcept)
371 typedef typename _Sequence::value_type value_type;
372 typedef typename _Sequence::reference reference;
373 typedef typename _Sequence::const_reference const_reference;
374 typedef typename _Sequence::size_type size_type;
375 typedef _Sequence container_type;
378 // See queue::c for notes on these names.
384 * @brief Default constructor creates no elements.
386 #ifndef __GXX_EXPERIMENTAL_CXX0X__
388 priority_queue(const _Compare& __x = _Compare(),
389 const _Sequence& __s = _Sequence())
391 { std::make_heap(c.begin(), c.end(), comp); }
394 priority_queue(const _Compare& __x,
395 const _Sequence& __s)
397 { std::make_heap(c.begin(), c.end(), comp); }
400 priority_queue(const _Compare& __x = _Compare(),
401 _Sequence&& __s = _Sequence())
402 : c(std::move(__s)), comp(__x)
403 { std::make_heap(c.begin(), c.end(), comp); }
407 * @brief Builds a %queue from a range.
408 * @param first An input iterator.
409 * @param last An input iterator.
410 * @param x A comparison functor describing a strict weak ordering.
411 * @param s An initial sequence with which to start.
413 * Begins by copying @a s, inserting a copy of the elements
414 * from @a [first,last) into the copy of @a s, then ordering
415 * the copy according to @a x.
417 * For more information on function objects, see the
418 * documentation on @link functors functor base
421 #ifndef __GXX_EXPERIMENTAL_CXX0X__
422 template<typename _InputIterator>
423 priority_queue(_InputIterator __first, _InputIterator __last,
424 const _Compare& __x = _Compare(),
425 const _Sequence& __s = _Sequence())
428 __glibcxx_requires_valid_range(__first, __last);
429 c.insert(c.end(), __first, __last);
430 std::make_heap(c.begin(), c.end(), comp);
433 template<typename _InputIterator>
434 priority_queue(_InputIterator __first, _InputIterator __last,
436 const _Sequence& __s)
439 __glibcxx_requires_valid_range(__first, __last);
440 c.insert(c.end(), __first, __last);
441 std::make_heap(c.begin(), c.end(), comp);
444 template<typename _InputIterator>
445 priority_queue(_InputIterator __first, _InputIterator __last,
446 const _Compare& __x = _Compare(),
447 _Sequence&& __s = _Sequence())
448 : c(std::move(__s)), comp(__x)
450 __glibcxx_requires_valid_range(__first, __last);
451 c.insert(c.end(), __first, __last);
452 std::make_heap(c.begin(), c.end(), comp);
457 * Returns true if the %queue is empty.
461 { return c.empty(); }
463 /** Returns the number of elements in the %queue. */
469 * Returns a read-only (constant) reference to the data at the first
470 * element of the %queue.
475 __glibcxx_requires_nonempty();
480 * @brief Add data to the %queue.
481 * @param x Data to be added.
483 * This is a typical %queue operation.
484 * The time complexity of the operation depends on the underlying
488 push(const value_type& __x)
491 std::push_heap(c.begin(), c.end(), comp);
494 #ifdef __GXX_EXPERIMENTAL_CXX0X__
496 push(value_type&& __x)
498 c.push_back(std::move(__x));
499 std::push_heap(c.begin(), c.end(), comp);
502 template<typename... _Args>
504 emplace(_Args&&... __args)
506 c.emplace_back(std::forward<_Args>(__args)...);
507 std::push_heap(c.begin(), c.end(), comp);
512 * @brief Removes first element.
514 * This is a typical %queue operation. It shrinks the %queue
515 * by one. The time complexity of the operation depends on the
516 * underlying sequence.
518 * Note that no data is returned, and if the first element's
519 * data is needed, it should be retrieved before pop() is
525 __glibcxx_requires_nonempty();
526 std::pop_heap(c.begin(), c.end(), comp);
530 #ifdef __GXX_EXPERIMENTAL_CXX0X__
532 swap(priority_queue& __pq)
536 swap(comp, __pq.comp);
541 // No equality/comparison operators are provided for priority_queue.
543 #ifdef __GXX_EXPERIMENTAL_CXX0X__
544 template<typename _Tp, typename _Sequence, typename _Compare>
546 swap(priority_queue<_Tp, _Sequence, _Compare>& __x,
547 priority_queue<_Tp, _Sequence, _Compare>& __y)
550 template<typename _Tp, typename _Sequence, typename _Compare,
552 struct uses_allocator<priority_queue<_Tp, _Sequence, _Compare>, _Alloc>
553 : public uses_allocator<_Sequence, _Alloc>::type { };
556 _GLIBCXX_END_NAMESPACE_VERSION
559 #endif /* _STL_QUEUE_H */