libstdc++
stl_multiset.h
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1 // Multiset implementation -*- C++ -*-
2 
3 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
4 // 2011 Free Software Foundation, Inc.
5 //
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25 
26 /*
27  *
28  * Copyright (c) 1994
29  * Hewlett-Packard Company
30  *
31  * Permission to use, copy, modify, distribute and sell this software
32  * and its documentation for any purpose is hereby granted without fee,
33  * provided that the above copyright notice appear in all copies and
34  * that both that copyright notice and this permission notice appear
35  * in supporting documentation. Hewlett-Packard Company makes no
36  * representations about the suitability of this software for any
37  * purpose. It is provided "as is" without express or implied warranty.
38  *
39  *
40  * Copyright (c) 1996
41  * Silicon Graphics Computer Systems, Inc.
42  *
43  * Permission to use, copy, modify, distribute and sell this software
44  * and its documentation for any purpose is hereby granted without fee,
45  * provided that the above copyright notice appear in all copies and
46  * that both that copyright notice and this permission notice appear
47  * in supporting documentation. Silicon Graphics makes no
48  * representations about the suitability of this software for any
49  * purpose. It is provided "as is" without express or implied warranty.
50  */
51 
52 /** @file bits/stl_multiset.h
53  * This is an internal header file, included by other library headers.
54  * Do not attempt to use it directly. @headername{set}
55  */
56 
57 #ifndef _STL_MULTISET_H
58 #define _STL_MULTISET_H 1
59 
60 #include <bits/concept_check.h>
61 #ifdef __GXX_EXPERIMENTAL_CXX0X__
62 #include <initializer_list>
63 #endif
64 
65 namespace std _GLIBCXX_VISIBILITY(default)
66 {
67 _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
68 
69  /**
70  * @brief A standard container made up of elements, which can be retrieved
71  * in logarithmic time.
72  *
73  * @ingroup associative_containers
74  *
75  * Meets the requirements of a <a href="tables.html#65">container</a>, a
76  * <a href="tables.html#66">reversible container</a>, and an
77  * <a href="tables.html#69">associative container</a> (using equivalent
78  * keys). For a @c multiset<Key> the key_type and value_type are Key.
79  *
80  * Multisets support bidirectional iterators.
81  *
82  * The private tree data is declared exactly the same way for set and
83  * multiset; the distinction is made entirely in how the tree functions are
84  * called (*_unique versus *_equal, same as the standard).
85  */
86  template <typename _Key, typename _Compare = std::less<_Key>,
87  typename _Alloc = std::allocator<_Key> >
88  class multiset
89  {
90  // concept requirements
91  typedef typename _Alloc::value_type _Alloc_value_type;
92  __glibcxx_class_requires(_Key, _SGIAssignableConcept)
93  __glibcxx_class_requires4(_Compare, bool, _Key, _Key,
94  _BinaryFunctionConcept)
95  __glibcxx_class_requires2(_Key, _Alloc_value_type, _SameTypeConcept)
96 
97  public:
98  // typedefs:
99  typedef _Key key_type;
100  typedef _Key value_type;
101  typedef _Compare key_compare;
102  typedef _Compare value_compare;
103  typedef _Alloc allocator_type;
104 
105  private:
106  /// This turns a red-black tree into a [multi]set.
107  typedef typename _Alloc::template rebind<_Key>::other _Key_alloc_type;
108 
109  typedef _Rb_tree<key_type, value_type, _Identity<value_type>,
110  key_compare, _Key_alloc_type> _Rep_type;
111  /// The actual tree structure.
112  _Rep_type _M_t;
113 
114  public:
115  typedef typename _Key_alloc_type::pointer pointer;
116  typedef typename _Key_alloc_type::const_pointer const_pointer;
117  typedef typename _Key_alloc_type::reference reference;
118  typedef typename _Key_alloc_type::const_reference const_reference;
119  // _GLIBCXX_RESOLVE_LIB_DEFECTS
120  // DR 103. set::iterator is required to be modifiable,
121  // but this allows modification of keys.
122  typedef typename _Rep_type::const_iterator iterator;
123  typedef typename _Rep_type::const_iterator const_iterator;
126  typedef typename _Rep_type::size_type size_type;
127  typedef typename _Rep_type::difference_type difference_type;
128 
129  // allocation/deallocation
130  /**
131  * @brief Default constructor creates no elements.
132  */
134  : _M_t() { }
135 
136  /**
137  * @brief Creates a %multiset with no elements.
138  * @param __comp Comparator to use.
139  * @param __a An allocator object.
140  */
141  explicit
142  multiset(const _Compare& __comp,
143  const allocator_type& __a = allocator_type())
144  : _M_t(__comp, _Key_alloc_type(__a)) { }
145 
146  /**
147  * @brief Builds a %multiset from a range.
148  * @param __first An input iterator.
149  * @param __last An input iterator.
150  *
151  * Create a %multiset consisting of copies of the elements from
152  * [first,last). This is linear in N if the range is already sorted,
153  * and NlogN otherwise (where N is distance(__first,__last)).
154  */
155  template<typename _InputIterator>
156  multiset(_InputIterator __first, _InputIterator __last)
157  : _M_t()
158  { _M_t._M_insert_equal(__first, __last); }
159 
160  /**
161  * @brief Builds a %multiset from a range.
162  * @param __first An input iterator.
163  * @param __last An input iterator.
164  * @param __comp A comparison functor.
165  * @param __a An allocator object.
166  *
167  * Create a %multiset consisting of copies of the elements from
168  * [__first,__last). This is linear in N if the range is already sorted,
169  * and NlogN otherwise (where N is distance(__first,__last)).
170  */
171  template<typename _InputIterator>
172  multiset(_InputIterator __first, _InputIterator __last,
173  const _Compare& __comp,
174  const allocator_type& __a = allocator_type())
175  : _M_t(__comp, _Key_alloc_type(__a))
176  { _M_t._M_insert_equal(__first, __last); }
177 
178  /**
179  * @brief %Multiset copy constructor.
180  * @param __x A %multiset of identical element and allocator types.
181  *
182  * The newly-created %multiset uses a copy of the allocation object used
183  * by @a __x.
184  */
185  multiset(const multiset& __x)
186  : _M_t(__x._M_t) { }
187 
188 #ifdef __GXX_EXPERIMENTAL_CXX0X__
189  /**
190  * @brief %Multiset move constructor.
191  * @param __x A %multiset of identical element and allocator types.
192  *
193  * The newly-created %multiset contains the exact contents of @a __x.
194  * The contents of @a __x are a valid, but unspecified %multiset.
195  */
197  noexcept(is_nothrow_copy_constructible<_Compare>::value)
198  : _M_t(std::move(__x._M_t)) { }
199 
200  /**
201  * @brief Builds a %multiset from an initializer_list.
202  * @param __l An initializer_list.
203  * @param __comp A comparison functor.
204  * @param __a An allocator object.
205  *
206  * Create a %multiset consisting of copies of the elements from
207  * the list. This is linear in N if the list is already sorted,
208  * and NlogN otherwise (where N is @a __l.size()).
209  */
211  const _Compare& __comp = _Compare(),
212  const allocator_type& __a = allocator_type())
213  : _M_t(__comp, _Key_alloc_type(__a))
214  { _M_t._M_insert_equal(__l.begin(), __l.end()); }
215 #endif
216 
217  /**
218  * @brief %Multiset assignment operator.
219  * @param __x A %multiset of identical element and allocator types.
220  *
221  * All the elements of @a __x are copied, but unlike the copy
222  * constructor, the allocator object is not copied.
223  */
224  multiset&
225  operator=(const multiset& __x)
226  {
227  _M_t = __x._M_t;
228  return *this;
229  }
230 
231 #ifdef __GXX_EXPERIMENTAL_CXX0X__
232  /**
233  * @brief %Multiset move assignment operator.
234  * @param __x A %multiset of identical element and allocator types.
235  *
236  * The contents of @a __x are moved into this %multiset
237  * (without copying). @a __x is a valid, but unspecified
238  * %multiset.
239  */
240  multiset&
242  {
243  // NB: DR 1204.
244  // NB: DR 675.
245  this->clear();
246  this->swap(__x);
247  return *this;
248  }
249 
250  /**
251  * @brief %Multiset list assignment operator.
252  * @param __l An initializer_list.
253  *
254  * This function fills a %multiset with copies of the elements in the
255  * initializer list @a __l.
256  *
257  * Note that the assignment completely changes the %multiset and
258  * that the resulting %multiset's size is the same as the number
259  * of elements assigned. Old data may be lost.
260  */
261  multiset&
263  {
264  this->clear();
265  this->insert(__l.begin(), __l.end());
266  return *this;
267  }
268 #endif
269 
270  // accessors:
271 
272  /// Returns the comparison object.
273  key_compare
274  key_comp() const
275  { return _M_t.key_comp(); }
276  /// Returns the comparison object.
277  value_compare
278  value_comp() const
279  { return _M_t.key_comp(); }
280  /// Returns the memory allocation object.
281  allocator_type
282  get_allocator() const _GLIBCXX_NOEXCEPT
283  { return allocator_type(_M_t.get_allocator()); }
284 
285  /**
286  * Returns a read-only (constant) iterator that points to the first
287  * element in the %multiset. Iteration is done in ascending order
288  * according to the keys.
289  */
290  iterator
291  begin() const _GLIBCXX_NOEXCEPT
292  { return _M_t.begin(); }
293 
294  /**
295  * Returns a read-only (constant) iterator that points one past the last
296  * element in the %multiset. Iteration is done in ascending order
297  * according to the keys.
298  */
299  iterator
300  end() const _GLIBCXX_NOEXCEPT
301  { return _M_t.end(); }
302 
303  /**
304  * Returns a read-only (constant) reverse iterator that points to the
305  * last element in the %multiset. Iteration is done in descending order
306  * according to the keys.
307  */
309  rbegin() const _GLIBCXX_NOEXCEPT
310  { return _M_t.rbegin(); }
311 
312  /**
313  * Returns a read-only (constant) reverse iterator that points to the
314  * last element in the %multiset. Iteration is done in descending order
315  * according to the keys.
316  */
318  rend() const _GLIBCXX_NOEXCEPT
319  { return _M_t.rend(); }
320 
321 #ifdef __GXX_EXPERIMENTAL_CXX0X__
322  /**
323  * Returns a read-only (constant) iterator that points to the first
324  * element in the %multiset. Iteration is done in ascending order
325  * according to the keys.
326  */
327  iterator
328  cbegin() const noexcept
329  { return _M_t.begin(); }
330 
331  /**
332  * Returns a read-only (constant) iterator that points one past the last
333  * element in the %multiset. Iteration is done in ascending order
334  * according to the keys.
335  */
336  iterator
337  cend() const noexcept
338  { return _M_t.end(); }
339 
340  /**
341  * Returns a read-only (constant) reverse iterator that points to the
342  * last element in the %multiset. Iteration is done in descending order
343  * according to the keys.
344  */
346  crbegin() const noexcept
347  { return _M_t.rbegin(); }
348 
349  /**
350  * Returns a read-only (constant) reverse iterator that points to the
351  * last element in the %multiset. Iteration is done in descending order
352  * according to the keys.
353  */
355  crend() const noexcept
356  { return _M_t.rend(); }
357 #endif
358 
359  /// Returns true if the %set is empty.
360  bool
361  empty() const _GLIBCXX_NOEXCEPT
362  { return _M_t.empty(); }
363 
364  /// Returns the size of the %set.
365  size_type
366  size() const _GLIBCXX_NOEXCEPT
367  { return _M_t.size(); }
368 
369  /// Returns the maximum size of the %set.
370  size_type
371  max_size() const _GLIBCXX_NOEXCEPT
372  { return _M_t.max_size(); }
373 
374  /**
375  * @brief Swaps data with another %multiset.
376  * @param __x A %multiset of the same element and allocator types.
377  *
378  * This exchanges the elements between two multisets in constant time.
379  * (It is only swapping a pointer, an integer, and an instance of the @c
380  * Compare type (which itself is often stateless and empty), so it should
381  * be quite fast.)
382  * Note that the global std::swap() function is specialized such that
383  * std::swap(s1,s2) will feed to this function.
384  */
385  void
387  { _M_t.swap(__x._M_t); }
388 
389  // insert/erase
390  /**
391  * @brief Inserts an element into the %multiset.
392  * @param __x Element to be inserted.
393  * @return An iterator that points to the inserted element.
394  *
395  * This function inserts an element into the %multiset. Contrary
396  * to a std::set the %multiset does not rely on unique keys and thus
397  * multiple copies of the same element can be inserted.
398  *
399  * Insertion requires logarithmic time.
400  */
401  iterator
402  insert(const value_type& __x)
403  { return _M_t._M_insert_equal(__x); }
404 
405 #ifdef __GXX_EXPERIMENTAL_CXX0X__
406  iterator
407  insert(value_type&& __x)
408  { return _M_t._M_insert_equal(std::move(__x)); }
409 #endif
410 
411  /**
412  * @brief Inserts an element into the %multiset.
413  * @param __position An iterator that serves as a hint as to where the
414  * element should be inserted.
415  * @param __x Element to be inserted.
416  * @return An iterator that points to the inserted element.
417  *
418  * This function inserts an element into the %multiset. Contrary
419  * to a std::set the %multiset does not rely on unique keys and thus
420  * multiple copies of the same element can be inserted.
421  *
422  * Note that the first parameter is only a hint and can potentially
423  * improve the performance of the insertion process. A bad hint would
424  * cause no gains in efficiency.
425  *
426  * See http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt07ch17.html
427  * for more on @a hinting.
428  *
429  * Insertion requires logarithmic time (if the hint is not taken).
430  */
431  iterator
432  insert(const_iterator __position, const value_type& __x)
433  { return _M_t._M_insert_equal_(__position, __x); }
434 
435 #ifdef __GXX_EXPERIMENTAL_CXX0X__
436  iterator
437  insert(const_iterator __position, value_type&& __x)
438  { return _M_t._M_insert_equal_(__position, std::move(__x)); }
439 #endif
440 
441  /**
442  * @brief A template function that tries to insert a range of elements.
443  * @param __first Iterator pointing to the start of the range to be
444  * inserted.
445  * @param __last Iterator pointing to the end of the range.
446  *
447  * Complexity similar to that of the range constructor.
448  */
449  template<typename _InputIterator>
450  void
451  insert(_InputIterator __first, _InputIterator __last)
452  { _M_t._M_insert_equal(__first, __last); }
453 
454 #ifdef __GXX_EXPERIMENTAL_CXX0X__
455  /**
456  * @brief Attempts to insert a list of elements into the %multiset.
457  * @param __l A std::initializer_list<value_type> of elements
458  * to be inserted.
459  *
460  * Complexity similar to that of the range constructor.
461  */
462  void
464  { this->insert(__l.begin(), __l.end()); }
465 #endif
466 
467 #ifdef __GXX_EXPERIMENTAL_CXX0X__
468  // _GLIBCXX_RESOLVE_LIB_DEFECTS
469  // DR 130. Associative erase should return an iterator.
470  /**
471  * @brief Erases an element from a %multiset.
472  * @param __position An iterator pointing to the element to be erased.
473  * @return An iterator pointing to the element immediately following
474  * @a position prior to the element being erased. If no such
475  * element exists, end() is returned.
476  *
477  * This function erases an element, pointed to by the given iterator,
478  * from a %multiset. Note that this function only erases the element,
479  * and that if the element is itself a pointer, the pointed-to memory is
480  * not touched in any way. Managing the pointer is the user's
481  * responsibility.
482  */
483  iterator
484  erase(const_iterator __position)
485  { return _M_t.erase(__position); }
486 #else
487  /**
488  * @brief Erases an element from a %multiset.
489  * @param __position An iterator pointing to the element to be erased.
490  *
491  * This function erases an element, pointed to by the given iterator,
492  * from a %multiset. Note that this function only erases the element,
493  * and that if the element is itself a pointer, the pointed-to memory is
494  * not touched in any way. Managing the pointer is the user's
495  * responsibility.
496  */
497  void
498  erase(iterator __position)
499  { _M_t.erase(__position); }
500 #endif
501 
502  /**
503  * @brief Erases elements according to the provided key.
504  * @param __x Key of element to be erased.
505  * @return The number of elements erased.
506  *
507  * This function erases all elements located by the given key from a
508  * %multiset.
509  * Note that this function only erases the element, and that if
510  * the element is itself a pointer, the pointed-to memory is not touched
511  * in any way. Managing the pointer is the user's responsibility.
512  */
513  size_type
514  erase(const key_type& __x)
515  { return _M_t.erase(__x); }
516 
517 #ifdef __GXX_EXPERIMENTAL_CXX0X__
518  // _GLIBCXX_RESOLVE_LIB_DEFECTS
519  // DR 130. Associative erase should return an iterator.
520  /**
521  * @brief Erases a [first,last) range of elements from a %multiset.
522  * @param __first Iterator pointing to the start of the range to be
523  * erased.
524  * @param __last Iterator pointing to the end of the range to
525  * be erased.
526  * @return The iterator @a last.
527  *
528  * This function erases a sequence of elements from a %multiset.
529  * Note that this function only erases the elements, and that if
530  * the elements themselves are pointers, the pointed-to memory is not
531  * touched in any way. Managing the pointer is the user's
532  * responsibility.
533  */
534  iterator
535  erase(const_iterator __first, const_iterator __last)
536  { return _M_t.erase(__first, __last); }
537 #else
538  /**
539  * @brief Erases a [first,last) range of elements from a %multiset.
540  * @param first Iterator pointing to the start of the range to be
541  * erased.
542  * @param last Iterator pointing to the end of the range to be erased.
543  *
544  * This function erases a sequence of elements from a %multiset.
545  * Note that this function only erases the elements, and that if
546  * the elements themselves are pointers, the pointed-to memory is not
547  * touched in any way. Managing the pointer is the user's
548  * responsibility.
549  */
550  void
551  erase(iterator __first, iterator __last)
552  { _M_t.erase(__first, __last); }
553 #endif
554 
555  /**
556  * Erases all elements in a %multiset. Note that this function only
557  * erases the elements, and that if the elements themselves are pointers,
558  * the pointed-to memory is not touched in any way. Managing the pointer
559  * is the user's responsibility.
560  */
561  void
562  clear() _GLIBCXX_NOEXCEPT
563  { _M_t.clear(); }
564 
565  // multiset operations:
566 
567  /**
568  * @brief Finds the number of elements with given key.
569  * @param __x Key of elements to be located.
570  * @return Number of elements with specified key.
571  */
572  size_type
573  count(const key_type& __x) const
574  { return _M_t.count(__x); }
575 
576  // _GLIBCXX_RESOLVE_LIB_DEFECTS
577  // 214. set::find() missing const overload
578  //@{
579  /**
580  * @brief Tries to locate an element in a %set.
581  * @param __x Element to be located.
582  * @return Iterator pointing to sought-after element, or end() if not
583  * found.
584  *
585  * This function takes a key and tries to locate the element with which
586  * the key matches. If successful the function returns an iterator
587  * pointing to the sought after element. If unsuccessful it returns the
588  * past-the-end ( @c end() ) iterator.
589  */
590  iterator
591  find(const key_type& __x)
592  { return _M_t.find(__x); }
593 
594  const_iterator
595  find(const key_type& __x) const
596  { return _M_t.find(__x); }
597  //@}
598 
599  //@{
600  /**
601  * @brief Finds the beginning of a subsequence matching given key.
602  * @param __x Key to be located.
603  * @return Iterator pointing to first element equal to or greater
604  * than key, or end().
605  *
606  * This function returns the first element of a subsequence of elements
607  * that matches the given key. If unsuccessful it returns an iterator
608  * pointing to the first element that has a greater value than given key
609  * or end() if no such element exists.
610  */
611  iterator
612  lower_bound(const key_type& __x)
613  { return _M_t.lower_bound(__x); }
614 
615  const_iterator
616  lower_bound(const key_type& __x) const
617  { return _M_t.lower_bound(__x); }
618  //@}
619 
620  //@{
621  /**
622  * @brief Finds the end of a subsequence matching given key.
623  * @param __x Key to be located.
624  * @return Iterator pointing to the first element
625  * greater than key, or end().
626  */
627  iterator
628  upper_bound(const key_type& __x)
629  { return _M_t.upper_bound(__x); }
630 
631  const_iterator
632  upper_bound(const key_type& __x) const
633  { return _M_t.upper_bound(__x); }
634  //@}
635 
636  //@{
637  /**
638  * @brief Finds a subsequence matching given key.
639  * @param __x Key to be located.
640  * @return Pair of iterators that possibly points to the subsequence
641  * matching given key.
642  *
643  * This function is equivalent to
644  * @code
645  * std::make_pair(c.lower_bound(val),
646  * c.upper_bound(val))
647  * @endcode
648  * (but is faster than making the calls separately).
649  *
650  * This function probably only makes sense for multisets.
651  */
653  equal_range(const key_type& __x)
654  { return _M_t.equal_range(__x); }
655 
657  equal_range(const key_type& __x) const
658  { return _M_t.equal_range(__x); }
659  //@}
660 
661  template<typename _K1, typename _C1, typename _A1>
662  friend bool
663  operator==(const multiset<_K1, _C1, _A1>&,
664  const multiset<_K1, _C1, _A1>&);
665 
666  template<typename _K1, typename _C1, typename _A1>
667  friend bool
668  operator< (const multiset<_K1, _C1, _A1>&,
669  const multiset<_K1, _C1, _A1>&);
670  };
671 
672  /**
673  * @brief Multiset equality comparison.
674  * @param __x A %multiset.
675  * @param __y A %multiset of the same type as @a __x.
676  * @return True iff the size and elements of the multisets are equal.
677  *
678  * This is an equivalence relation. It is linear in the size of the
679  * multisets.
680  * Multisets are considered equivalent if their sizes are equal, and if
681  * corresponding elements compare equal.
682  */
683  template<typename _Key, typename _Compare, typename _Alloc>
684  inline bool
685  operator==(const multiset<_Key, _Compare, _Alloc>& __x,
687  { return __x._M_t == __y._M_t; }
688 
689  /**
690  * @brief Multiset ordering relation.
691  * @param __x A %multiset.
692  * @param __y A %multiset of the same type as @a __x.
693  * @return True iff @a __x is lexicographically less than @a __y.
694  *
695  * This is a total ordering relation. It is linear in the size of the
696  * maps. The elements must be comparable with @c <.
697  *
698  * See std::lexicographical_compare() for how the determination is made.
699  */
700  template<typename _Key, typename _Compare, typename _Alloc>
701  inline bool
702  operator<(const multiset<_Key, _Compare, _Alloc>& __x,
704  { return __x._M_t < __y._M_t; }
705 
706  /// Returns !(x == y).
707  template<typename _Key, typename _Compare, typename _Alloc>
708  inline bool
709  operator!=(const multiset<_Key, _Compare, _Alloc>& __x,
711  { return !(__x == __y); }
712 
713  /// Returns y < x.
714  template<typename _Key, typename _Compare, typename _Alloc>
715  inline bool
716  operator>(const multiset<_Key,_Compare,_Alloc>& __x,
718  { return __y < __x; }
719 
720  /// Returns !(y < x)
721  template<typename _Key, typename _Compare, typename _Alloc>
722  inline bool
723  operator<=(const multiset<_Key, _Compare, _Alloc>& __x,
725  { return !(__y < __x); }
726 
727  /// Returns !(x < y)
728  template<typename _Key, typename _Compare, typename _Alloc>
729  inline bool
730  operator>=(const multiset<_Key, _Compare, _Alloc>& __x,
732  { return !(__x < __y); }
733 
734  /// See std::multiset::swap().
735  template<typename _Key, typename _Compare, typename _Alloc>
736  inline void
739  { __x.swap(__y); }
740 
741 _GLIBCXX_END_NAMESPACE_CONTAINER
742 } // namespace std
743 
744 #endif /* _STL_MULTISET_H */