# stl_queue.h

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    00001 // Queue implementation -*- C++ -*-
    00002
    00003 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
    00004 // Free Software Foundation, Inc.
    00005 //
    00006 // This file is part of the GNU ISO C++ Library.  This library is free
    00007 // software; you can redistribute it and/or modify it under the
    00008 // terms of the GNU General Public License as published by the
    00009 // Free Software Foundation; either version 3, or (at your option)
    00010 // any later version.
    00011
    00012 // This library is distributed in the hope that it will be useful,
    00013 // but WITHOUT ANY WARRANTY; without even the implied warranty of
    00014 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    00015 // GNU General Public License for more details.
    00016
    00017 // Under Section 7 of GPL version 3, you are granted additional
    00018 // permissions described in the GCC Runtime Library Exception, version
    00019 // 3.1, as published by the Free Software Foundation.
    00020
    00021 // You should have received a copy of the GNU General Public License and
    00022 // a copy of the GCC Runtime Library Exception along with this program;
    00023 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
    00024 // <http://www.gnu.org/licenses/>.
    00025
    00026 /*
    00027  *
    00028  * Copyright (c) 1994
    00029  * Hewlett-Packard Company
    00030  *
    00031  * Permission to use, copy, modify, distribute and sell this software
    00032  * and its documentation for any purpose is hereby granted without fee,
    00033  * provided that the above copyright notice appear in all copies and
    00034  * that both that copyright notice and this permission notice appear
    00035  * in supporting documentation.  Hewlett-Packard Company makes no
    00036  * representations about the suitability of this software for any
    00037  * purpose.  It is provided "as is" without express or implied warranty.
    00038  *
    00039  *
    00040  * Copyright (c) 1996,1997
    00041  * Silicon Graphics Computer Systems, Inc.
    00042  *
    00043  * Permission to use, copy, modify, distribute and sell this software
    00044  * and its documentation for any purpose is hereby granted without fee,
    00045  * provided that the above copyright notice appear in all copies and
    00046  * that both that copyright notice and this permission notice appear
    00047  * in supporting documentation.  Silicon Graphics makes no
    00048  * representations about the suitability of this software for any
    00049  * purpose.  It is provided "as is" without express or implied warranty.
    00050  */
    00051
    00052 /** @file stl_queue.h
    00053  *  This is an internal header file, included by other library headers.
    00054  *  You should not attempt to use it directly.
    00055  */
    00056
    00057 #ifndef _STL_QUEUE_H
    00058 #define _STL_QUEUE_H 1
    00059
    00060 #include <bits/concept_check.h>
    00061 #include <debug/debug.h>
    00062
    00063 _GLIBCXX_BEGIN_NAMESPACE(std)
    00064
    00065   /**
    00066    *  @brief  A standard container giving FIFO behavior.
    00067    *
    00068    *  @ingroup sequences
    00069    *
    00070    *  Meets many of the requirements of a
    00071    *  <a href="tables.html#65">container</a>,
    00072    *  but does not define anything to do with iterators.  Very few of the
    00073    *  other standard container interfaces are defined.
    00074    *
    00075    *  This is not a true container, but an @e adaptor.  It holds another
    00076    *  container, and provides a wrapper interface to that container.  The
    00077    *  wrapper is what enforces strict first-in-first-out %queue behavior.
    00078    *
    00079    *  The second template parameter defines the type of the underlying
    00080    *  sequence/container.  It defaults to std::deque, but it can be any type
    00081    *  that supports @c front, @c back, @c push_back, and @c pop_front,
    00082    *  such as std::list or an appropriate user-defined type.
    00083    *
    00084    *  Members not found in @a normal containers are @c container_type,
    00085    *  which is a typedef for the second Sequence parameter, and @c push and
    00086    *  @c pop, which are standard %queue/FIFO operations.
    00087   */
    00088   template<typename _Tp, typename _Sequence = deque<_Tp> >
    00089     class queue
    00090     {
    00091       // concept requirements
    00092       typedef typename _Sequence::value_type _Sequence_value_type;
    00093       __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
    00094       __glibcxx_class_requires(_Sequence, _FrontInsertionSequenceConcept)
    00095       __glibcxx_class_requires(_Sequence, _BackInsertionSequenceConcept)
    00096       __glibcxx_class_requires2(_Tp, _Sequence_value_type, _SameTypeConcept)
    00097
    00098       template<typename _Tp1, typename _Seq1>
    00099         friend bool
    00100         operator==(const queue<_Tp1, _Seq1>&, const queue<_Tp1, _Seq1>&);
    00101
    00102       template<typename _Tp1, typename _Seq1>
    00103         friend bool
    00104         operator<(const queue<_Tp1, _Seq1>&, const queue<_Tp1, _Seq1>&);
    00105
    00106     public:
    00107       typedef typename _Sequence::value_type                value_type;
    00108       typedef typename _Sequence::reference                 reference;
    00109       typedef typename _Sequence::const_reference           const_reference;
    00110       typedef typename _Sequence::size_type                 size_type;
    00111       typedef          _Sequence                            container_type;
    00112
    00113     protected:
    00114       /**
    00115        *  'c' is the underlying container.  Maintainers wondering why
    00116        *  this isn't uglified as per style guidelines should note that
    00117        *  this name is specified in the standard, [23.2.3.1].  (Why?
    00118        *  Presumably for the same reason that it's protected instead
    00119        *  of private: to allow derivation.  But none of the other
    00120        *  containers allow for derivation.  Odd.)
    00121        */
    00122       _Sequence c;
    00123
    00124     public:
    00125       /**
    00126        *  @brief  Default constructor creates no elements.
    00127        */
    00128 #ifndef __GXX_EXPERIMENTAL_CXX0X__
    00129       explicit
    00130       queue(const _Sequence& __c = _Sequence())
    00131       : c(__c) { }
    00132 #else
    00133       explicit
    00134       queue(const _Sequence& __c)
    00135       : c(__c) { }
    00136
    00137       explicit
    00138       queue(_Sequence&& __c = _Sequence())
    00139       : c(std::move(__c)) { }
    00140
    00141       queue(queue&& __q)
    00142       : c(std::move(__q.c)) { }
    00143
    00144       queue&
    00145       operator=(queue&& __q)
    00146       {
    00147     c = std::move(__q.c);
    00148     return *this;
    00149       }
    00150 #endif
    00151
    00152       /**
    00153        *  Returns true if the %queue is empty.
    00154        */
    00155       bool
    00156       empty() const
    00157       { return c.empty(); }
    00158
    00159       /**  Returns the number of elements in the %queue.  */
    00160       size_type
    00161       size() const
    00162       { return c.size(); }
    00163
    00164       /**
    00165        *  Returns a read/write reference to the data at the first
    00166        *  element of the %queue.
    00167        */
    00168       reference
    00169       front()
    00170       {
    00171     __glibcxx_requires_nonempty();
    00172     return c.front();
    00173       }
    00174
    00175       /**
    00176        *  Returns a read-only (constant) reference to the data at the first
    00177        *  element of the %queue.
    00178        */
    00179       const_reference
    00180       front() const
    00181       {
    00182     __glibcxx_requires_nonempty();
    00183     return c.front();
    00184       }
    00185
    00186       /**
    00187        *  Returns a read/write reference to the data at the last
    00188        *  element of the %queue.
    00189        */
    00190       reference
    00191       back()
    00192       {
    00193     __glibcxx_requires_nonempty();
    00194     return c.back();
    00195       }
    00196
    00197       /**
    00198        *  Returns a read-only (constant) reference to the data at the last
    00199        *  element of the %queue.
    00200        */
    00201       const_reference
    00202       back() const
    00203       {
    00204     __glibcxx_requires_nonempty();
    00205     return c.back();
    00206       }
    00207
    00208       /**
    00209        *  @brief  Add data to the end of the %queue.
    00210        *  @param  x  Data to be added.
    00211        *
    00212        *  This is a typical %queue operation.  The function creates an
    00213        *  element at the end of the %queue and assigns the given data
    00214        *  to it.  The time complexity of the operation depends on the
    00215        *  underlying sequence.
    00216        */
    00217       void
    00218       push(const value_type& __x)
    00219       { c.push_back(__x); }
    00220
    00221 #ifdef __GXX_EXPERIMENTAL_CXX0X__
    00222       void
    00223       push(value_type&& __x)
    00224       { c.push_back(std::move(__x)); }
    00225
    00226       template<typename... _Args>
    00227         void
    00228         emplace(_Args&&... __args)
    00229     { c.emplace_back(std::forward<_Args>(__args)...); }
    00230 #endif
    00231
    00232       /**
    00233        *  @brief  Removes first element.
    00234        *
    00235        *  This is a typical %queue operation.  It shrinks the %queue by one.
    00236        *  The time complexity of the operation depends on the underlying
    00237        *  sequence.
    00238        *
    00239        *  Note that no data is returned, and if the first element's
    00240        *  data is needed, it should be retrieved before pop() is
    00241        *  called.
    00242        */
    00243       void
    00244       pop()
    00245       {
    00246     __glibcxx_requires_nonempty();
    00247     c.pop_front();
    00248       }
    00249
    00250 #ifdef __GXX_EXPERIMENTAL_CXX0X__
    00251       void
    00252       swap(queue& __q)
    00253       { c.swap(__q.c); }
    00254 #endif
    00255     };
    00256
    00257   /**
    00258    *  @brief  Queue equality comparison.
    00259    *  @param  x  A %queue.
    00260    *  @param  y  A %queue of the same type as @a x.
    00261    *  @return  True iff the size and elements of the queues are equal.
    00262    *
    00263    *  This is an equivalence relation.  Complexity and semantics depend on the
    00264    *  underlying sequence type, but the expected rules are:  this relation is
    00265    *  linear in the size of the sequences, and queues are considered equivalent
    00266    *  if their sequences compare equal.
    00267   */
    00268   template<typename _Tp, typename _Seq>
    00269     inline bool
    00270     operator==(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
    00271     { return __x.c == __y.c; }
    00272
    00273   /**
    00274    *  @brief  Queue ordering relation.
    00275    *  @param  x  A %queue.
    00276    *  @param  y  A %queue of the same type as @a x.
    00277    *  @return  True iff @a x is lexicographically less than @a y.
    00278    *
    00279    *  This is an total ordering relation.  Complexity and semantics
    00280    *  depend on the underlying sequence type, but the expected rules
    00281    *  are: this relation is linear in the size of the sequences, the
    00282    *  elements must be comparable with @c <, and
    00283    *  std::lexicographical_compare() is usually used to make the
    00284    *  determination.
    00285   */
    00286   template<typename _Tp, typename _Seq>
    00287     inline bool
    00288     operator<(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
    00289     { return __x.c < __y.c; }
    00290
    00291   /// Based on operator==
    00292   template<typename _Tp, typename _Seq>
    00293     inline bool
    00294     operator!=(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
    00295     { return !(__x == __y); }
    00296
    00297   /// Based on operator<
    00298   template<typename _Tp, typename _Seq>
    00299     inline bool
    00300     operator>(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
    00301     { return __y < __x; }
    00302
    00303   /// Based on operator<
    00304   template<typename _Tp, typename _Seq>
    00305     inline bool
    00306     operator<=(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
    00307     { return !(__y < __x); }
    00308
    00309   /// Based on operator<
    00310   template<typename _Tp, typename _Seq>
    00311     inline bool
    00312     operator>=(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
    00313     { return !(__x < __y); }
    00314
    00315 #ifdef __GXX_EXPERIMENTAL_CXX0X__
    00316   template<typename _Tp, typename _Seq>
    00317     inline void
    00318     swap(queue<_Tp, _Seq>& __x, queue<_Tp, _Seq>& __y)
    00319     { __x.swap(__y); }
    00320 #endif
    00321
    00322   /**
    00323    *  @brief  A standard container automatically sorting its contents.
    00324    *
    00325    *  @ingroup sequences
    00326    *
    00327    *  This is not a true container, but an @e adaptor.  It holds
    00328    *  another container, and provides a wrapper interface to that
    00329    *  container.  The wrapper is what enforces priority-based sorting
    00330    *  and %queue behavior.  Very few of the standard container/sequence
    00331    *  interface requirements are met (e.g., iterators).
    00332    *
    00333    *  The second template parameter defines the type of the underlying
    00334    *  sequence/container.  It defaults to std::vector, but it can be
    00335    *  any type that supports @c front(), @c push_back, @c pop_back,
    00336    *  and random-access iterators, such as std::deque or an
    00337    *  appropriate user-defined type.
    00338    *
    00339    *  The third template parameter supplies the means of making
    00340    *  priority comparisons.  It defaults to @c less<value_type> but
    00341    *  can be anything defining a strict weak ordering.
    00342    *
    00343    *  Members not found in @a normal containers are @c container_type,
    00344    *  which is a typedef for the second Sequence parameter, and @c
    00345    *  push, @c pop, and @c top, which are standard %queue operations.
    00346    *
    00347    *  @note No equality/comparison operators are provided for
    00348    *  %priority_queue.
    00349    *
    00350    *  @note Sorting of the elements takes place as they are added to,
    00351    *  and removed from, the %priority_queue using the
    00352    *  %priority_queue's member functions.  If you access the elements
    00353    *  by other means, and change their data such that the sorting
    00354    *  order would be different, the %priority_queue will not re-sort
    00355    *  the elements for you.  (How could it know to do so?)
    00356   */
    00357   template<typename _Tp, typename _Sequence = vector<_Tp>,
    00358        typename _Compare  = less<typename _Sequence::value_type> >
    00359     class priority_queue
    00360     {
    00361       // concept requirements
    00362       typedef typename _Sequence::value_type _Sequence_value_type;
    00363       __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
    00364       __glibcxx_class_requires(_Sequence, _SequenceConcept)
    00365       __glibcxx_class_requires(_Sequence, _RandomAccessContainerConcept)
    00366       __glibcxx_class_requires2(_Tp, _Sequence_value_type, _SameTypeConcept)
    00367       __glibcxx_class_requires4(_Compare, bool, _Tp, _Tp,
    00368                 _BinaryFunctionConcept)
    00369
    00370     public:
    00371       typedef typename _Sequence::value_type                value_type;
    00372       typedef typename _Sequence::reference                 reference;
    00373       typedef typename _Sequence::const_reference           const_reference;
    00374       typedef typename _Sequence::size_type                 size_type;
    00375       typedef          _Sequence                            container_type;
    00376
    00377     protected:
    00378       //  See queue::c for notes on these names.
    00379       _Sequence  c;
    00380       _Compare   comp;
    00381
    00382     public:
    00383       /**
    00384        *  @brief  Default constructor creates no elements.
    00385        */
    00386 #ifndef __GXX_EXPERIMENTAL_CXX0X__
    00387       explicit
    00388       priority_queue(const _Compare& __x = _Compare(),
    00389              const _Sequence& __s = _Sequence())
    00390       : c(__s), comp(__x)
    00391       { std::make_heap(c.begin(), c.end(), comp); }
    00392 #else
    00393       explicit
    00394       priority_queue(const _Compare& __x,
    00395              const _Sequence& __s)
    00396       : c(__s), comp(__x)
    00397       { std::make_heap(c.begin(), c.end(), comp); }
    00398
    00399       explicit
    00400       priority_queue(const _Compare& __x = _Compare(),
    00401              _Sequence&& __s = _Sequence())
    00402       : c(std::move(__s)), comp(__x)
    00403       { std::make_heap(c.begin(), c.end(), comp); }
    00404 #endif
    00405
    00406       /**
    00407        *  @brief  Builds a %queue from a range.
    00408        *  @param  first  An input iterator.
    00409        *  @param  last  An input iterator.
    00410        *  @param  x  A comparison functor describing a strict weak ordering.
    00411        *  @param  s  An initial sequence with which to start.
    00412        *
    00413        *  Begins by copying @a s, inserting a copy of the elements
    00414        *  from @a [first,last) into the copy of @a s, then ordering
    00415        *  the copy according to @a x.
    00416        *
    00417        *  For more information on function objects, see the
    00418        *  documentation on @link functors functor base
    00419        *  classes@endlink.
    00420        */
    00421 #ifndef __GXX_EXPERIMENTAL_CXX0X__
    00422       template<typename _InputIterator>
    00423         priority_queue(_InputIterator __first, _InputIterator __last,
    00424                const _Compare& __x = _Compare(),
    00425                const _Sequence& __s = _Sequence())
    00426     : c(__s), comp(__x)
    00427         {
    00428       __glibcxx_requires_valid_range(__first, __last);
    00429       c.insert(c.end(), __first, __last);
    00430       std::make_heap(c.begin(), c.end(), comp);
    00431     }
    00432 #else
    00433       template<typename _InputIterator>
    00434         priority_queue(_InputIterator __first, _InputIterator __last,
    00435                const _Compare& __x,
    00436                const _Sequence& __s)
    00437     : c(__s), comp(__x)
    00438         {
    00439       __glibcxx_requires_valid_range(__first, __last);
    00440       c.insert(c.end(), __first, __last);
    00441       std::make_heap(c.begin(), c.end(), comp);
    00442     }
    00443
    00444       template<typename _InputIterator>
    00445         priority_queue(_InputIterator __first, _InputIterator __last,
    00446                const _Compare& __x = _Compare(),
    00447                _Sequence&& __s = _Sequence())
    00448     : c(std::move(__s)), comp(__x)
    00449         {
    00450       __glibcxx_requires_valid_range(__first, __last);
    00451       c.insert(c.end(), __first, __last);
    00452       std::make_heap(c.begin(), c.end(), comp);
    00453     }
    00454
    00455       priority_queue(priority_queue&& __pq)
    00456       : c(std::move(__pq.c)), comp(std::move(__pq.comp)) { }
    00457
    00458       priority_queue&
    00459       operator=(priority_queue&& __pq)
    00460       {
    00461     c = std::move(__pq.c);
    00462     comp = std::move(__pq.comp);
    00463     return *this;
    00464       }
    00465 #endif
    00466
    00467       /**
    00468        *  Returns true if the %queue is empty.
    00469        */
    00470       bool
    00471       empty() const
    00472       { return c.empty(); }
    00473
    00474       /**  Returns the number of elements in the %queue.  */
    00475       size_type
    00476       size() const
    00477       { return c.size(); }
    00478
    00479       /**
    00480        *  Returns a read-only (constant) reference to the data at the first
    00481        *  element of the %queue.
    00482        */
    00483       const_reference
    00484       top() const
    00485       {
    00486     __glibcxx_requires_nonempty();
    00487     return c.front();
    00488       }
    00489
    00490       /**
    00491        *  @brief  Add data to the %queue.
    00492        *  @param  x  Data to be added.
    00493        *
    00494        *  This is a typical %queue operation.
    00495        *  The time complexity of the operation depends on the underlying
    00496        *  sequence.
    00497        */
    00498       void
    00499       push(const value_type& __x)
    00500       {
    00501     c.push_back(__x);
    00502     std::push_heap(c.begin(), c.end(), comp);
    00503       }
    00504
    00505 #ifdef __GXX_EXPERIMENTAL_CXX0X__
    00506       void
    00507       push(value_type&& __x)
    00508       {
    00509     c.push_back(std::move(__x));
    00510     std::push_heap(c.begin(), c.end(), comp);
    00511       }
    00512
    00513       template<typename... _Args>
    00514         void
    00515         emplace(_Args&&... __args)
    00516     {
    00517       c.emplace_back(std::forward<_Args>(__args)...);
    00518       std::push_heap(c.begin(), c.end(), comp);
    00519     }
    00520 #endif
    00521
    00522       /**
    00523        *  @brief  Removes first element.
    00524        *
    00525        *  This is a typical %queue operation.  It shrinks the %queue
    00526        *  by one.  The time complexity of the operation depends on the
    00527        *  underlying sequence.
    00528        *
    00529        *  Note that no data is returned, and if the first element's
    00530        *  data is needed, it should be retrieved before pop() is
    00531        *  called.
    00532        */
    00533       void
    00534       pop()
    00535       {
    00536     __glibcxx_requires_nonempty();
    00537     std::pop_heap(c.begin(), c.end(), comp);
    00538     c.pop_back();
    00539       }
    00540
    00541 #ifdef __GXX_EXPERIMENTAL_CXX0X__
    00542       void
    00543       swap(priority_queue& __pq)
    00544       {
    00545     using std::swap;
    00546     c.swap(__pq.c);
    00547     swap(comp, __pq.comp);
    00548       }
    00549 #endif
    00550     };
    00551
    00552   // No equality/comparison operators are provided for priority_queue.
    00553
    00554 #ifdef __GXX_EXPERIMENTAL_CXX0X__
    00555   template<typename _Tp, typename _Sequence, typename _Compare>
    00556     inline void
    00557     swap(priority_queue<_Tp, _Sequence, _Compare>& __x,
    00558      priority_queue<_Tp, _Sequence, _Compare>& __y)
    00559     { __x.swap(__y); }
    00560 #endif
    00561
    00562 _GLIBCXX_END_NAMESPACE
    00563
    00564 #endif /* _STL_QUEUE_H */