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1 : // Queue implementation -*- C++ -*-
2 :
3 : // Copyright (C) 2001-2013 Free Software Foundation, Inc.
4 : //
5 : // This file is part of the GNU ISO C++ Library. This library is free
6 : // software; you can redistribute it and/or modify it under the
7 : // terms of the GNU General Public License as published by the
8 : // Free Software Foundation; either version 3, or (at your option)
9 : // any later version.
10 :
11 : // This library is distributed in the hope that it will be useful,
12 : // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 : // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 : // GNU General Public License for more details.
15 :
16 : // Under Section 7 of GPL version 3, you are granted additional
17 : // permissions described in the GCC Runtime Library Exception, version
18 : // 3.1, as published by the Free Software Foundation.
19 :
20 : // You should have received a copy of the GNU General Public License and
21 : // a copy of the GCC Runtime Library Exception along with this program;
22 : // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 : // <http://www.gnu.org/licenses/>.
24 :
25 : /*
26 : *
27 : * Copyright (c) 1994
28 : * Hewlett-Packard Company
29 : *
30 : * Permission to use, copy, modify, distribute and sell this software
31 : * and its documentation for any purpose is hereby granted without fee,
32 : * provided that the above copyright notice appear in all copies and
33 : * that both that copyright notice and this permission notice appear
34 : * in supporting documentation. Hewlett-Packard Company makes no
35 : * representations about the suitability of this software for any
36 : * purpose. It is provided "as is" without express or implied warranty.
37 : *
38 : *
39 : * Copyright (c) 1996,1997
40 : * Silicon Graphics Computer Systems, Inc.
41 : *
42 : * Permission to use, copy, modify, distribute and sell this software
43 : * and its documentation for any purpose is hereby granted without fee,
44 : * provided that the above copyright notice appear in all copies and
45 : * that both that copyright notice and this permission notice appear
46 : * in supporting documentation. Silicon Graphics makes no
47 : * representations about the suitability of this software for any
48 : * purpose. It is provided "as is" without express or implied warranty.
49 : */
50 :
51 : /** @file bits/stl_queue.h
52 : * This is an internal header file, included by other library headers.
53 : * Do not attempt to use it directly. @headername{queue}
54 : */
55 :
56 : #ifndef _STL_QUEUE_H
57 : #define _STL_QUEUE_H 1
58 :
59 : #include <bits/concept_check.h>
60 : #include <debug/debug.h>
61 :
62 : namespace std _GLIBCXX_VISIBILITY(default)
63 : {
64 : _GLIBCXX_BEGIN_NAMESPACE_VERSION
65 :
66 : /**
67 : * @brief A standard container giving FIFO behavior.
68 : *
69 : * @ingroup sequences
70 : *
71 : * @tparam _Tp Type of element.
72 : * @tparam _Sequence Type of underlying sequence, defaults to deque<_Tp>.
73 : *
74 : * Meets many of the requirements of a
75 : * <a href="tables.html#65">container</a>,
76 : * but does not define anything to do with iterators. Very few of the
77 : * other standard container interfaces are defined.
78 : *
79 : * This is not a true container, but an @e adaptor. It holds another
80 : * container, and provides a wrapper interface to that container. The
81 : * wrapper is what enforces strict first-in-first-out %queue behavior.
82 : *
83 : * The second template parameter defines the type of the underlying
84 : * sequence/container. It defaults to std::deque, but it can be any type
85 : * that supports @c front, @c back, @c push_back, and @c pop_front,
86 : * such as std::list or an appropriate user-defined type.
87 : *
88 : * Members not found in @a normal containers are @c container_type,
89 : * which is a typedef for the second Sequence parameter, and @c push and
90 : * @c pop, which are standard %queue/FIFO operations.
91 : */
92 : template<typename _Tp, typename _Sequence = deque<_Tp> >
93 178 : class queue
94 : {
95 : // concept requirements
96 : typedef typename _Sequence::value_type _Sequence_value_type;
97 : __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
98 : __glibcxx_class_requires(_Sequence, _FrontInsertionSequenceConcept)
99 : __glibcxx_class_requires(_Sequence, _BackInsertionSequenceConcept)
100 : __glibcxx_class_requires2(_Tp, _Sequence_value_type, _SameTypeConcept)
101 :
102 : template<typename _Tp1, typename _Seq1>
103 : friend bool
104 : operator==(const queue<_Tp1, _Seq1>&, const queue<_Tp1, _Seq1>&);
105 :
106 : template<typename _Tp1, typename _Seq1>
107 : friend bool
108 : operator<(const queue<_Tp1, _Seq1>&, const queue<_Tp1, _Seq1>&);
109 :
110 : public:
111 : typedef typename _Sequence::value_type value_type;
112 : typedef typename _Sequence::reference reference;
113 : typedef typename _Sequence::const_reference const_reference;
114 : typedef typename _Sequence::size_type size_type;
115 : typedef _Sequence container_type;
116 :
117 : protected:
118 : /**
119 : * 'c' is the underlying container. Maintainers wondering why
120 : * this isn't uglified as per style guidelines should note that
121 : * this name is specified in the standard, [23.2.3.1]. (Why?
122 : * Presumably for the same reason that it's protected instead
123 : * of private: to allow derivation. But none of the other
124 : * containers allow for derivation. Odd.)
125 : */
126 : _Sequence c;
127 :
128 : public:
129 : /**
130 : * @brief Default constructor creates no elements.
131 : */
132 : #if __cplusplus < 201103L
133 : explicit
134 : queue(const _Sequence& __c = _Sequence())
135 : : c(__c) { }
136 : #else
137 : explicit
138 : queue(const _Sequence& __c)
139 : : c(__c) { }
140 :
141 : explicit
142 178 : queue(_Sequence&& __c = _Sequence())
143 178 : : c(std::move(__c)) { }
144 : #endif
145 :
146 : /**
147 : * Returns true if the %queue is empty.
148 : */
149 : bool
150 350926 : empty() const
151 350926 : { return c.empty(); }
152 :
153 : /** Returns the number of elements in the %queue. */
154 : size_type
155 : size() const
156 : { return c.size(); }
157 :
158 : /**
159 : * Returns a read/write reference to the data at the first
160 : * element of the %queue.
161 : */
162 : reference
163 159756 : front()
164 : {
165 : __glibcxx_requires_nonempty();
166 159756 : return c.front();
167 : }
168 :
169 : /**
170 : * Returns a read-only (constant) reference to the data at the first
171 : * element of the %queue.
172 : */
173 : const_reference
174 : front() const
175 : {
176 : __glibcxx_requires_nonempty();
177 : return c.front();
178 : }
179 :
180 : /**
181 : * Returns a read/write reference to the data at the last
182 : * element of the %queue.
183 : */
184 : reference
185 : back()
186 : {
187 : __glibcxx_requires_nonempty();
188 : return c.back();
189 : }
190 :
191 : /**
192 : * Returns a read-only (constant) reference to the data at the last
193 : * element of the %queue.
194 : */
195 : const_reference
196 : back() const
197 : {
198 : __glibcxx_requires_nonempty();
199 : return c.back();
200 : }
201 :
202 : /**
203 : * @brief Add data to the end of the %queue.
204 : * @param __x Data to be added.
205 : *
206 : * This is a typical %queue operation. The function creates an
207 : * element at the end of the %queue and assigns the given data
208 : * to it. The time complexity of the operation depends on the
209 : * underlying sequence.
210 : */
211 : void
212 159756 : push(const value_type& __x)
213 159756 : { c.push_back(__x); }
214 :
215 : #if __cplusplus >= 201103L
216 : void
217 : push(value_type&& __x)
218 : { c.push_back(std::move(__x)); }
219 :
220 : template<typename... _Args>
221 : void
222 : emplace(_Args&&... __args)
223 : { c.emplace_back(std::forward<_Args>(__args)...); }
224 : #endif
225 :
226 : /**
227 : * @brief Removes first element.
228 : *
229 : * This is a typical %queue operation. It shrinks the %queue by one.
230 : * The time complexity of the operation depends on the underlying
231 : * sequence.
232 : *
233 : * Note that no data is returned, and if the first element's
234 : * data is needed, it should be retrieved before pop() is
235 : * called.
236 : */
237 : void
238 159756 : pop()
239 : {
240 : __glibcxx_requires_nonempty();
241 159756 : c.pop_front();
242 159756 : }
243 :
244 : #if __cplusplus >= 201103L
245 : void
246 : swap(queue& __q)
247 : noexcept(noexcept(swap(c, __q.c)))
248 : {
249 : using std::swap;
250 : swap(c, __q.c);
251 : }
252 : #endif
253 : };
254 :
255 : /**
256 : * @brief Queue equality comparison.
257 : * @param __x A %queue.
258 : * @param __y A %queue of the same type as @a __x.
259 : * @return True iff the size and elements of the queues are equal.
260 : *
261 : * This is an equivalence relation. Complexity and semantics depend on the
262 : * underlying sequence type, but the expected rules are: this relation is
263 : * linear in the size of the sequences, and queues are considered equivalent
264 : * if their sequences compare equal.
265 : */
266 : template<typename _Tp, typename _Seq>
267 : inline bool
268 : operator==(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
269 : { return __x.c == __y.c; }
270 :
271 : /**
272 : * @brief Queue ordering relation.
273 : * @param __x A %queue.
274 : * @param __y A %queue of the same type as @a x.
275 : * @return True iff @a __x is lexicographically less than @a __y.
276 : *
277 : * This is an total ordering relation. Complexity and semantics
278 : * depend on the underlying sequence type, but the expected rules
279 : * are: this relation is linear in the size of the sequences, the
280 : * elements must be comparable with @c <, and
281 : * std::lexicographical_compare() is usually used to make the
282 : * determination.
283 : */
284 : template<typename _Tp, typename _Seq>
285 : inline bool
286 : operator<(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
287 : { return __x.c < __y.c; }
288 :
289 : /// Based on operator==
290 : template<typename _Tp, typename _Seq>
291 : inline bool
292 : operator!=(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
293 : { return !(__x == __y); }
294 :
295 : /// Based on operator<
296 : template<typename _Tp, typename _Seq>
297 : inline bool
298 : operator>(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
299 : { return __y < __x; }
300 :
301 : /// Based on operator<
302 : template<typename _Tp, typename _Seq>
303 : inline bool
304 : operator<=(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
305 : { return !(__y < __x); }
306 :
307 : /// Based on operator<
308 : template<typename _Tp, typename _Seq>
309 : inline bool
310 : operator>=(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
311 : { return !(__x < __y); }
312 :
313 : #if __cplusplus >= 201103L
314 : template<typename _Tp, typename _Seq>
315 : inline void
316 : swap(queue<_Tp, _Seq>& __x, queue<_Tp, _Seq>& __y)
317 : noexcept(noexcept(__x.swap(__y)))
318 : { __x.swap(__y); }
319 :
320 : template<typename _Tp, typename _Seq, typename _Alloc>
321 : struct uses_allocator<queue<_Tp, _Seq>, _Alloc>
322 : : public uses_allocator<_Seq, _Alloc>::type { };
323 : #endif
324 :
325 : /**
326 : * @brief A standard container automatically sorting its contents.
327 : *
328 : * @ingroup sequences
329 : *
330 : * @tparam _Tp Type of element.
331 : * @tparam _Sequence Type of underlying sequence, defaults to vector<_Tp>.
332 : * @tparam _Compare Comparison function object type, defaults to
333 : * less<_Sequence::value_type>.
334 : *
335 : * This is not a true container, but an @e adaptor. It holds
336 : * another container, and provides a wrapper interface to that
337 : * container. The wrapper is what enforces priority-based sorting
338 : * and %queue behavior. Very few of the standard container/sequence
339 : * interface requirements are met (e.g., iterators).
340 : *
341 : * The second template parameter defines the type of the underlying
342 : * sequence/container. It defaults to std::vector, but it can be
343 : * any type that supports @c front(), @c push_back, @c pop_back,
344 : * and random-access iterators, such as std::deque or an
345 : * appropriate user-defined type.
346 : *
347 : * The third template parameter supplies the means of making
348 : * priority comparisons. It defaults to @c less<value_type> but
349 : * can be anything defining a strict weak ordering.
350 : *
351 : * Members not found in @a normal containers are @c container_type,
352 : * which is a typedef for the second Sequence parameter, and @c
353 : * push, @c pop, and @c top, which are standard %queue operations.
354 : *
355 : * @note No equality/comparison operators are provided for
356 : * %priority_queue.
357 : *
358 : * @note Sorting of the elements takes place as they are added to,
359 : * and removed from, the %priority_queue using the
360 : * %priority_queue's member functions. If you access the elements
361 : * by other means, and change their data such that the sorting
362 : * order would be different, the %priority_queue will not re-sort
363 : * the elements for you. (How could it know to do so?)
364 : */
365 : template<typename _Tp, typename _Sequence = vector<_Tp>,
366 : typename _Compare = less<typename _Sequence::value_type> >
367 : class priority_queue
368 : {
369 : // concept requirements
370 : typedef typename _Sequence::value_type _Sequence_value_type;
371 : __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
372 : __glibcxx_class_requires(_Sequence, _SequenceConcept)
373 : __glibcxx_class_requires(_Sequence, _RandomAccessContainerConcept)
374 : __glibcxx_class_requires2(_Tp, _Sequence_value_type, _SameTypeConcept)
375 : __glibcxx_class_requires4(_Compare, bool, _Tp, _Tp,
376 : _BinaryFunctionConcept)
377 :
378 : public:
379 : typedef typename _Sequence::value_type value_type;
380 : typedef typename _Sequence::reference reference;
381 : typedef typename _Sequence::const_reference const_reference;
382 : typedef typename _Sequence::size_type size_type;
383 : typedef _Sequence container_type;
384 :
385 : protected:
386 : // See queue::c for notes on these names.
387 : _Sequence c;
388 : _Compare comp;
389 :
390 : public:
391 : /**
392 : * @brief Default constructor creates no elements.
393 : */
394 : #if __cplusplus < 201103L
395 : explicit
396 : priority_queue(const _Compare& __x = _Compare(),
397 : const _Sequence& __s = _Sequence())
398 : : c(__s), comp(__x)
399 : { std::make_heap(c.begin(), c.end(), comp); }
400 : #else
401 : explicit
402 : priority_queue(const _Compare& __x,
403 : const _Sequence& __s)
404 : : c(__s), comp(__x)
405 : { std::make_heap(c.begin(), c.end(), comp); }
406 :
407 : explicit
408 : priority_queue(const _Compare& __x = _Compare(),
409 : _Sequence&& __s = _Sequence())
410 : : c(std::move(__s)), comp(__x)
411 : { std::make_heap(c.begin(), c.end(), comp); }
412 : #endif
413 :
414 : /**
415 : * @brief Builds a %queue from a range.
416 : * @param __first An input iterator.
417 : * @param __last An input iterator.
418 : * @param __x A comparison functor describing a strict weak ordering.
419 : * @param __s An initial sequence with which to start.
420 : *
421 : * Begins by copying @a __s, inserting a copy of the elements
422 : * from @a [first,last) into the copy of @a __s, then ordering
423 : * the copy according to @a __x.
424 : *
425 : * For more information on function objects, see the
426 : * documentation on @link functors functor base
427 : * classes@endlink.
428 : */
429 : #if __cplusplus < 201103L
430 : template<typename _InputIterator>
431 : priority_queue(_InputIterator __first, _InputIterator __last,
432 : const _Compare& __x = _Compare(),
433 : const _Sequence& __s = _Sequence())
434 : : c(__s), comp(__x)
435 : {
436 : __glibcxx_requires_valid_range(__first, __last);
437 : c.insert(c.end(), __first, __last);
438 : std::make_heap(c.begin(), c.end(), comp);
439 : }
440 : #else
441 : template<typename _InputIterator>
442 : priority_queue(_InputIterator __first, _InputIterator __last,
443 : const _Compare& __x,
444 : const _Sequence& __s)
445 : : c(__s), comp(__x)
446 : {
447 : __glibcxx_requires_valid_range(__first, __last);
448 : c.insert(c.end(), __first, __last);
449 : std::make_heap(c.begin(), c.end(), comp);
450 : }
451 :
452 : template<typename _InputIterator>
453 : priority_queue(_InputIterator __first, _InputIterator __last,
454 : const _Compare& __x = _Compare(),
455 : _Sequence&& __s = _Sequence())
456 : : c(std::move(__s)), comp(__x)
457 : {
458 : __glibcxx_requires_valid_range(__first, __last);
459 : c.insert(c.end(), __first, __last);
460 : std::make_heap(c.begin(), c.end(), comp);
461 : }
462 : #endif
463 :
464 : /**
465 : * Returns true if the %queue is empty.
466 : */
467 : bool
468 : empty() const
469 : { return c.empty(); }
470 :
471 : /** Returns the number of elements in the %queue. */
472 : size_type
473 : size() const
474 : { return c.size(); }
475 :
476 : /**
477 : * Returns a read-only (constant) reference to the data at the first
478 : * element of the %queue.
479 : */
480 : const_reference
481 : top() const
482 : {
483 : __glibcxx_requires_nonempty();
484 : return c.front();
485 : }
486 :
487 : /**
488 : * @brief Add data to the %queue.
489 : * @param __x Data to be added.
490 : *
491 : * This is a typical %queue operation.
492 : * The time complexity of the operation depends on the underlying
493 : * sequence.
494 : */
495 : void
496 : push(const value_type& __x)
497 : {
498 : c.push_back(__x);
499 : std::push_heap(c.begin(), c.end(), comp);
500 : }
501 :
502 : #if __cplusplus >= 201103L
503 : void
504 : push(value_type&& __x)
505 : {
506 : c.push_back(std::move(__x));
507 : std::push_heap(c.begin(), c.end(), comp);
508 : }
509 :
510 : template<typename... _Args>
511 : void
512 : emplace(_Args&&... __args)
513 : {
514 : c.emplace_back(std::forward<_Args>(__args)...);
515 : std::push_heap(c.begin(), c.end(), comp);
516 : }
517 : #endif
518 :
519 : /**
520 : * @brief Removes first element.
521 : *
522 : * This is a typical %queue operation. It shrinks the %queue
523 : * by one. The time complexity of the operation depends on the
524 : * underlying sequence.
525 : *
526 : * Note that no data is returned, and if the first element's
527 : * data is needed, it should be retrieved before pop() is
528 : * called.
529 : */
530 : void
531 : pop()
532 : {
533 : __glibcxx_requires_nonempty();
534 : std::pop_heap(c.begin(), c.end(), comp);
535 : c.pop_back();
536 : }
537 :
538 : #if __cplusplus >= 201103L
539 : void
540 : swap(priority_queue& __pq)
541 : noexcept(noexcept(swap(c, __pq.c)) && noexcept(swap(comp, __pq.comp)))
542 : {
543 : using std::swap;
544 : swap(c, __pq.c);
545 : swap(comp, __pq.comp);
546 : }
547 : #endif
548 : };
549 :
550 : // No equality/comparison operators are provided for priority_queue.
551 :
552 : #if __cplusplus >= 201103L
553 : template<typename _Tp, typename _Sequence, typename _Compare>
554 : inline void
555 : swap(priority_queue<_Tp, _Sequence, _Compare>& __x,
556 : priority_queue<_Tp, _Sequence, _Compare>& __y)
557 : noexcept(noexcept(__x.swap(__y)))
558 : { __x.swap(__y); }
559 :
560 : template<typename _Tp, typename _Sequence, typename _Compare,
561 : typename _Alloc>
562 : struct uses_allocator<priority_queue<_Tp, _Sequence, _Compare>, _Alloc>
563 : : public uses_allocator<_Sequence, _Alloc>::type { };
564 : #endif
565 :
566 : _GLIBCXX_END_NAMESPACE_VERSION
567 : } // namespace
568 :
569 : #endif /* _STL_QUEUE_H */
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