1 // Queue implementation -*- C++ -*-
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58 * This is an internal header file, included by other library headers.
59 * You should not attempt to use it directly.
63 #define _STL_QUEUE_H 1
65 #include <bits/concept_check.h>
66 #include <debug/debug.h>
68 _GLIBCXX_BEGIN_NAMESPACE(std)
71 * @brief A standard container giving FIFO behavior.
76 * Meets many of the requirements of a
77 * <a href="tables.html#65">container</a>,
78 * but does not define anything to do with iterators. Very few of the
79 * other standard container interfaces are defined.
81 * This is not a true container, but an @e adaptor. It holds another
82 * container, and provides a wrapper interface to that container. The
83 * wrapper is what enforces strict first-in-first-out %queue behavior.
85 * The second template parameter defines the type of the underlying
86 * sequence/container. It defaults to std::deque, but it can be any type
87 * that supports @c front, @c back, @c push_back, and @c pop_front,
88 * such as std::list or an appropriate user-defined type.
90 * Members not found in "normal" containers are @c container_type,
91 * which is a typedef for the second Sequence parameter, and @c push and
92 * @c pop, which are standard %queue/FIFO operations.
94 template<typename _Tp, typename _Sequence = deque<_Tp> >
97 // concept requirements
98 typedef typename _Sequence::value_type _Sequence_value_type;
99 __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
100 __glibcxx_class_requires(_Sequence, _FrontInsertionSequenceConcept)
101 __glibcxx_class_requires(_Sequence, _BackInsertionSequenceConcept)
102 __glibcxx_class_requires2(_Tp, _Sequence_value_type, _SameTypeConcept)
104 template<typename _Tp1, typename _Seq1>
106 operator==(const queue<_Tp1, _Seq1>&, const queue<_Tp1, _Seq1>&);
108 template<typename _Tp1, typename _Seq1>
110 operator<(const queue<_Tp1, _Seq1>&, const queue<_Tp1, _Seq1>&);
113 typedef typename _Sequence::value_type value_type;
114 typedef typename _Sequence::reference reference;
115 typedef typename _Sequence::const_reference const_reference;
116 typedef typename _Sequence::size_type size_type;
117 typedef _Sequence container_type;
121 * 'c' is the underlying container. Maintainers wondering why
122 * this isn't uglified as per style guidelines should note that
123 * this name is specified in the standard, [23.2.3.1]. (Why?
124 * Presumably for the same reason that it's protected instead
125 * of private: to allow derivation. But none of the other
126 * containers allow for derivation. Odd.)
132 * @brief Default constructor creates no elements.
134 #ifndef __GXX_EXPERIMENTAL_CXX0X__
136 queue(const _Sequence& __c = _Sequence())
140 queue(const _Sequence& __c)
144 queue(_Sequence&& __c = _Sequence())
145 : c(std::move(__c)) { }
148 : c(std::move(__q.c)) { }
151 operator=(queue&& __q)
153 c = std::move(__q.c);
159 * Returns true if the %queue is empty.
163 { return c.empty(); }
165 /** Returns the number of elements in the %queue. */
171 * Returns a read/write reference to the data at the first
172 * element of the %queue.
177 __glibcxx_requires_nonempty();
182 * Returns a read-only (constant) reference to the data at the first
183 * element of the %queue.
188 __glibcxx_requires_nonempty();
193 * Returns a read/write reference to the data at the last
194 * element of the %queue.
199 __glibcxx_requires_nonempty();
204 * Returns a read-only (constant) reference to the data at the last
205 * element of the %queue.
210 __glibcxx_requires_nonempty();
215 * @brief Add data to the end of the %queue.
216 * @param x Data to be added.
218 * This is a typical %queue operation. The function creates an
219 * element at the end of the %queue and assigns the given data
220 * to it. The time complexity of the operation depends on the
221 * underlying sequence.
223 #ifndef __GXX_EXPERIMENTAL_CXX0X__
225 push(const value_type& __x)
226 { c.push_back(__x); }
229 template<typename... _Args>
231 push(_Args&&... __args)
232 { c.push_back(std::forward<_Args>(__args)...); }
236 * @brief Removes first element.
238 * This is a typical %queue operation. It shrinks the %queue by one.
239 * The time complexity of the operation depends on the underlying
242 * Note that no data is returned, and if the first element's
243 * data is needed, it should be retrieved before pop() is
249 __glibcxx_requires_nonempty();
253 #ifdef __GXX_EXPERIMENTAL_CXX0X__
261 * @brief Queue equality comparison.
263 * @param y A %queue of the same type as @a x.
264 * @return True iff the size and elements of the queues are equal.
266 * This is an equivalence relation. Complexity and semantics depend on the
267 * underlying sequence type, but the expected rules are: this relation is
268 * linear in the size of the sequences, and queues are considered equivalent
269 * if their sequences compare equal.
271 template<typename _Tp, typename _Seq>
273 operator==(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
274 { return __x.c == __y.c; }
277 * @brief Queue ordering relation.
279 * @param y A %queue of the same type as @a x.
280 * @return True iff @a x is lexicographically less than @a y.
282 * This is an total ordering relation. Complexity and semantics
283 * depend on the underlying sequence type, but the expected rules
284 * are: this relation is linear in the size of the sequences, the
285 * elements must be comparable with @c <, and
286 * std::lexicographical_compare() is usually used to make the
289 template<typename _Tp, typename _Seq>
291 operator<(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
292 { return __x.c < __y.c; }
294 /// Based on operator==
295 template<typename _Tp, typename _Seq>
297 operator!=(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
298 { return !(__x == __y); }
300 /// Based on operator<
301 template<typename _Tp, typename _Seq>
303 operator>(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
304 { return __y < __x; }
306 /// Based on operator<
307 template<typename _Tp, typename _Seq>
309 operator<=(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
310 { return !(__y < __x); }
312 /// Based on operator<
313 template<typename _Tp, typename _Seq>
315 operator>=(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
316 { return !(__x < __y); }
318 #ifdef __GXX_EXPERIMENTAL_CXX0X__
319 template<typename _Tp, typename _Seq>
321 swap(queue<_Tp, _Seq>& __x, queue<_Tp, _Seq>& __y)
324 template<typename _Tp, typename _Seq>
326 swap(queue<_Tp, _Seq>&& __x, queue<_Tp, _Seq>& __y)
329 template<typename _Tp, typename _Seq>
331 swap(queue<_Tp, _Seq>& __x, queue<_Tp, _Seq>&& __y)
336 * @brief A standard container automatically sorting its contents.
338 * @ingroup Containers
341 * This is not a true container, but an @e adaptor. It holds
342 * another container, and provides a wrapper interface to that
343 * container. The wrapper is what enforces priority-based sorting
344 * and %queue behavior. Very few of the standard container/sequence
345 * interface requirements are met (e.g., iterators).
347 * The second template parameter defines the type of the underlying
348 * sequence/container. It defaults to std::vector, but it can be
349 * any type that supports @c front(), @c push_back, @c pop_back,
350 * and random-access iterators, such as std::deque or an
351 * appropriate user-defined type.
353 * The third template parameter supplies the means of making
354 * priority comparisons. It defaults to @c less<value_type> but
355 * can be anything defining a strict weak ordering.
357 * Members not found in "normal" containers are @c container_type,
358 * which is a typedef for the second Sequence parameter, and @c
359 * push, @c pop, and @c top, which are standard %queue operations.
361 * @note No equality/comparison operators are provided for
364 * @note Sorting of the elements takes place as they are added to,
365 * and removed from, the %priority_queue using the
366 * %priority_queue's member functions. If you access the elements
367 * by other means, and change their data such that the sorting
368 * order would be different, the %priority_queue will not re-sort
369 * the elements for you. (How could it know to do so?)
371 template<typename _Tp, typename _Sequence = vector<_Tp>,
372 typename _Compare = less<typename _Sequence::value_type> >
375 // concept requirements
376 typedef typename _Sequence::value_type _Sequence_value_type;
377 __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
378 __glibcxx_class_requires(_Sequence, _SequenceConcept)
379 __glibcxx_class_requires(_Sequence, _RandomAccessContainerConcept)
380 __glibcxx_class_requires2(_Tp, _Sequence_value_type, _SameTypeConcept)
381 __glibcxx_class_requires4(_Compare, bool, _Tp, _Tp,
382 _BinaryFunctionConcept)
385 typedef typename _Sequence::value_type value_type;
386 typedef typename _Sequence::reference reference;
387 typedef typename _Sequence::const_reference const_reference;
388 typedef typename _Sequence::size_type size_type;
389 typedef _Sequence container_type;
392 // See queue::c for notes on these names.
398 * @brief Default constructor creates no elements.
400 #ifndef __GXX_EXPERIMENTAL_CXX0X__
402 priority_queue(const _Compare& __x = _Compare(),
403 const _Sequence& __s = _Sequence())
405 { std::make_heap(c.begin(), c.end(), comp); }
408 priority_queue(const _Compare& __x,
409 const _Sequence& __s)
411 { std::make_heap(c.begin(), c.end(), comp); }
414 priority_queue(const _Compare& __x = _Compare(),
415 _Sequence&& __s = _Sequence())
416 : c(std::move(__s)), comp(__x)
417 { std::make_heap(c.begin(), c.end(), comp); }
421 * @brief Builds a %queue from a range.
422 * @param first An input iterator.
423 * @param last An input iterator.
424 * @param x A comparison functor describing a strict weak ordering.
425 * @param s An initial sequence with which to start.
427 * Begins by copying @a s, inserting a copy of the elements
428 * from @a [first,last) into the copy of @a s, then ordering
429 * the copy according to @a x.
431 * For more information on function objects, see the
432 * documentation on @link s20_3_1_base functor base
435 #ifndef __GXX_EXPERIMENTAL_CXX0X__
436 template<typename _InputIterator>
437 priority_queue(_InputIterator __first, _InputIterator __last,
438 const _Compare& __x = _Compare(),
439 const _Sequence& __s = _Sequence())
442 __glibcxx_requires_valid_range(__first, __last);
443 c.insert(c.end(), __first, __last);
444 std::make_heap(c.begin(), c.end(), comp);
447 template<typename _InputIterator>
448 priority_queue(_InputIterator __first, _InputIterator __last,
450 const _Sequence& __s)
453 __glibcxx_requires_valid_range(__first, __last);
454 c.insert(c.end(), __first, __last);
455 std::make_heap(c.begin(), c.end(), comp);
458 template<typename _InputIterator>
459 priority_queue(_InputIterator __first, _InputIterator __last,
460 const _Compare& __x = _Compare(),
461 _Sequence&& __s = _Sequence())
462 : c(std::move(__s)), comp(__x)
464 __glibcxx_requires_valid_range(__first, __last);
465 c.insert(c.end(), __first, __last);
466 std::make_heap(c.begin(), c.end(), comp);
469 priority_queue(priority_queue&& __pq)
470 : c(std::move(__pq.c)), comp(std::move(__pq.comp)) { }
473 operator=(priority_queue&& __pq)
475 c = std::move(__pq.c);
476 comp = std::move(__pq.comp);
482 * Returns true if the %queue is empty.
486 { return c.empty(); }
488 /** Returns the number of elements in the %queue. */
494 * Returns a read-only (constant) reference to the data at the first
495 * element of the %queue.
500 __glibcxx_requires_nonempty();
505 * @brief Add data to the %queue.
506 * @param x Data to be added.
508 * This is a typical %queue operation.
509 * The time complexity of the operation depends on the underlying
512 #ifndef __GXX_EXPERIMENTAL_CXX0X__
514 push(const value_type& __x)
517 std::push_heap(c.begin(), c.end(), comp);
521 template<typename... _Args>
523 push(_Args&&... __args)
525 c.push_back(std::forward<_Args>(__args)...);
526 std::push_heap(c.begin(), c.end(), comp);
531 * @brief Removes first element.
533 * This is a typical %queue operation. It shrinks the %queue
534 * by one. The time complexity of the operation depends on the
535 * underlying sequence.
537 * Note that no data is returned, and if the first element's
538 * data is needed, it should be retrieved before pop() is
544 __glibcxx_requires_nonempty();
545 std::pop_heap(c.begin(), c.end(), comp);
549 #ifdef __GXX_EXPERIMENTAL_CXX0X__
551 swap(priority_queue&& __pq)
555 swap(comp, __pq.comp);
560 // No equality/comparison operators are provided for priority_queue.
562 #ifdef __GXX_EXPERIMENTAL_CXX0X__
563 template<typename _Tp, typename _Sequence, typename _Compare>
565 swap(priority_queue<_Tp, _Sequence, _Compare>& __x,
566 priority_queue<_Tp, _Sequence, _Compare>& __y)
569 template<typename _Tp, typename _Sequence, typename _Compare>
571 swap(priority_queue<_Tp, _Sequence, _Compare>&& __x,
572 priority_queue<_Tp, _Sequence, _Compare>& __y)
575 template<typename _Tp, typename _Sequence, typename _Compare>
577 swap(priority_queue<_Tp, _Sequence, _Compare>& __x,
578 priority_queue<_Tp, _Sequence, _Compare>&& __y)
582 _GLIBCXX_END_NAMESPACE
584 #endif /* _STL_QUEUE_H */