1 // Queue implementation -*- C++ -*-
3 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006
4 // Free Software Foundation, Inc.
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45 * Copyright (c) 1996,1997
46 * Silicon Graphics Computer Systems, Inc.
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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.
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.
135 queue(const _Sequence& __c = _Sequence()) : c(__c) {}
138 * Returns true if the %queue is empty.
142 { return c.empty(); }
144 /** Returns the number of elements in the %queue. */
150 * Returns a read/write reference to the data at the first
151 * element of the %queue.
156 __glibcxx_requires_nonempty();
161 * Returns a read-only (constant) reference to the data at the first
162 * element of the %queue.
167 __glibcxx_requires_nonempty();
172 * Returns a read/write reference to the data at the last
173 * element of the %queue.
178 __glibcxx_requires_nonempty();
183 * Returns a read-only (constant) reference to the data at the last
184 * element of the %queue.
189 __glibcxx_requires_nonempty();
194 * @brief Add data to the end of the %queue.
195 * @param x Data to be added.
197 * This is a typical %queue operation. The function creates an
198 * element at the end of the %queue and assigns the given data
199 * to it. The time complexity of the operation depends on the
200 * underlying sequence.
203 push(const value_type& __x)
204 { c.push_back(__x); }
207 * @brief Removes first element.
209 * This is a typical %queue operation. It shrinks the %queue by one.
210 * The time complexity of the operation depends on the underlying
213 * Note that no data is returned, and if the first element's
214 * data is needed, it should be retrieved before pop() is
220 __glibcxx_requires_nonempty();
227 * @brief Queue equality comparison.
229 * @param y A %queue of the same type as @a x.
230 * @return True iff the size and elements of the queues are equal.
232 * This is an equivalence relation. Complexity and semantics depend on the
233 * underlying sequence type, but the expected rules are: this relation is
234 * linear in the size of the sequences, and queues are considered equivalent
235 * if their sequences compare equal.
237 template<typename _Tp, typename _Seq>
239 operator==(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
240 { return __x.c == __y.c; }
243 * @brief Queue ordering relation.
245 * @param y A %queue of the same type as @a x.
246 * @return True iff @a x is lexicographically less than @a y.
248 * This is an total ordering relation. Complexity and semantics
249 * depend on the underlying sequence type, but the expected rules
250 * are: this relation is linear in the size of the sequences, the
251 * elements must be comparable with @c <, and
252 * std::lexicographical_compare() is usually used to make the
255 template<typename _Tp, typename _Seq>
257 operator<(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
258 { return __x.c < __y.c; }
260 /// Based on operator==
261 template<typename _Tp, typename _Seq>
263 operator!=(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
264 { return !(__x == __y); }
266 /// Based on operator<
267 template<typename _Tp, typename _Seq>
269 operator>(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
270 { return __y < __x; }
272 /// Based on operator<
273 template<typename _Tp, typename _Seq>
275 operator<=(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
276 { return !(__y < __x); }
278 /// Based on operator<
279 template<typename _Tp, typename _Seq>
281 operator>=(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
282 { return !(__x < __y); }
285 * @brief A standard container automatically sorting its contents.
287 * @ingroup Containers
290 * This is not a true container, but an @e adaptor. It holds
291 * another container, and provides a wrapper interface to that
292 * container. The wrapper is what enforces priority-based sorting
293 * and %queue behavior. Very few of the standard container/sequence
294 * interface requirements are met (e.g., iterators).
296 * The second template parameter defines the type of the underlying
297 * sequence/container. It defaults to std::vector, but it can be
298 * any type that supports @c front(), @c push_back, @c pop_back,
299 * and random-access iterators, such as std::deque or an
300 * appropriate user-defined type.
302 * The third template parameter supplies the means of making
303 * priority comparisons. It defaults to @c less<value_type> but
304 * can be anything defining a strict weak ordering.
306 * Members not found in "normal" containers are @c container_type,
307 * which is a typedef for the second Sequence parameter, and @c
308 * push, @c pop, and @c top, which are standard %queue operations.
310 * @note No equality/comparison operators are provided for
313 * @note Sorting of the elements takes place as they are added to,
314 * and removed from, the %priority_queue using the
315 * %priority_queue's member functions. If you access the elements
316 * by other means, and change their data such that the sorting
317 * order would be different, the %priority_queue will not re-sort
318 * the elements for you. (How could it know to do so?)
320 template<typename _Tp, typename _Sequence = vector<_Tp>,
321 typename _Compare = less<typename _Sequence::value_type> >
324 // concept requirements
325 typedef typename _Sequence::value_type _Sequence_value_type;
326 __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
327 __glibcxx_class_requires(_Sequence, _SequenceConcept)
328 __glibcxx_class_requires(_Sequence, _RandomAccessContainerConcept)
329 __glibcxx_class_requires2(_Tp, _Sequence_value_type, _SameTypeConcept)
330 __glibcxx_class_requires4(_Compare, bool, _Tp, _Tp,
331 _BinaryFunctionConcept)
334 typedef typename _Sequence::value_type value_type;
335 typedef typename _Sequence::reference reference;
336 typedef typename _Sequence::const_reference const_reference;
337 typedef typename _Sequence::size_type size_type;
338 typedef _Sequence container_type;
341 // See queue::c for notes on these names.
347 * @brief Default constructor creates no elements.
350 priority_queue(const _Compare& __x = _Compare(),
351 const _Sequence& __s = _Sequence())
353 { std::make_heap(c.begin(), c.end(), comp); }
356 * @brief Builds a %queue from a range.
357 * @param first An input iterator.
358 * @param last An input iterator.
359 * @param x A comparison functor describing a strict weak ordering.
360 * @param s An initial sequence with which to start.
362 * Begins by copying @a s, inserting a copy of the elements
363 * from @a [first,last) into the copy of @a s, then ordering
364 * the copy according to @a x.
366 * For more information on function objects, see the
367 * documentation on @link s20_3_1_base functor base
370 template<typename _InputIterator>
371 priority_queue(_InputIterator __first, _InputIterator __last,
372 const _Compare& __x = _Compare(),
373 const _Sequence& __s = _Sequence())
376 __glibcxx_requires_valid_range(__first, __last);
377 c.insert(c.end(), __first, __last);
378 std::make_heap(c.begin(), c.end(), comp);
382 * Returns true if the %queue is empty.
386 { return c.empty(); }
388 /** Returns the number of elements in the %queue. */
394 * Returns a read-only (constant) reference to the data at the first
395 * element of the %queue.
400 __glibcxx_requires_nonempty();
405 * @brief Add data to the %queue.
406 * @param x Data to be added.
408 * This is a typical %queue operation.
409 * The time complexity of the operation depends on the underlying
413 push(const value_type& __x)
416 std::push_heap(c.begin(), c.end(), comp);
420 * @brief Removes first element.
422 * This is a typical %queue operation. It shrinks the %queue
423 * by one. The time complexity of the operation depends on the
424 * underlying sequence.
426 * Note that no data is returned, and if the first element's
427 * data is needed, it should be retrieved before pop() is
433 __glibcxx_requires_nonempty();
434 std::pop_heap(c.begin(), c.end(), comp);
439 // No equality/comparison operators are provided for priority_queue.
441 _GLIBCXX_END_NAMESPACE
443 #endif /* _QUEUE_H */