libstdc++
unordered_map.h
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1 // unordered_map implementation -*- C++ -*-
2 
3 // Copyright (C) 2010-2013 Free Software Foundation, Inc.
4 //
5 // This file is part of the GNU ISO C++ Library. This library is free
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7 // terms of the GNU General Public License as published by the
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10 
11 // This library is distributed in the hope that it will be useful,
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15 
16 // Under Section 7 of GPL version 3, you are granted additional
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24 
25 /** @file bits/unordered_map.h
26  * This is an internal header file, included by other library headers.
27  * Do not attempt to use it directly. @headername{unordered_map}
28  */
29 
30 #ifndef _UNORDERED_MAP_H
31 #define _UNORDERED_MAP_H
32 
33 namespace std _GLIBCXX_VISIBILITY(default)
34 {
35 _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
36 
37  /// Base types for unordered_map.
38  template<bool _Cache>
40 
41  template<typename _Key,
42  typename _Tp,
43  typename _Hash = hash<_Key>,
44  typename _Pred = std::equal_to<_Key>,
48  _Alloc, __detail::_Select1st,
49  _Pred, _Hash,
53 
54  /// Base types for unordered_multimap.
55  template<bool _Cache>
57 
58  template<typename _Key,
59  typename _Tp,
60  typename _Hash = hash<_Key>,
61  typename _Pred = std::equal_to<_Key>,
65  _Alloc, __detail::_Select1st,
66  _Pred, _Hash,
67  __detail::_Mod_range_hashing,
68  __detail::_Default_ranged_hash,
69  __detail::_Prime_rehash_policy, _Tr>;
70 
71  /**
72  * @brief A standard container composed of unique keys (containing
73  * at most one of each key value) that associates values of another type
74  * with the keys.
75  *
76  * @ingroup unordered_associative_containers
77  *
78  * @tparam _Key Type of key objects.
79  * @tparam _Tp Type of mapped objects.
80  * @tparam _Hash Hashing function object type, defaults to hash<_Value>.
81  * @tparam _Pred Predicate function object type, defaults
82  * to equal_to<_Value>.
83  * @tparam _Alloc Allocator type, defaults to allocator<_Key>.
84  *
85  * Meets the requirements of a <a href="tables.html#65">container</a>, and
86  * <a href="tables.html#xx">unordered associative container</a>
87  *
88  * The resulting value type of the container is std::pair<const _Key, _Tp>.
89  *
90  * Base is _Hashtable, dispatched at compile time via template
91  * alias __umap_hashtable.
92  */
93  template<class _Key, class _Tp,
94  class _Hash = hash<_Key>,
95  class _Pred = std::equal_to<_Key>,
97  class unordered_map : __check_copy_constructible<_Alloc>
98  {
100  _Hashtable _M_h;
101 
102  public:
103  // typedefs:
104  //@{
105  /// Public typedefs.
106  typedef typename _Hashtable::key_type key_type;
107  typedef typename _Hashtable::value_type value_type;
108  typedef typename _Hashtable::mapped_type mapped_type;
109  typedef typename _Hashtable::hasher hasher;
110  typedef typename _Hashtable::key_equal key_equal;
111  typedef typename _Hashtable::allocator_type allocator_type;
112  //@}
113 
114  //@{
115  /// Iterator-related typedefs.
116  typedef typename allocator_type::pointer pointer;
117  typedef typename allocator_type::const_pointer const_pointer;
118  typedef typename allocator_type::reference reference;
119  typedef typename allocator_type::const_reference const_reference;
120  typedef typename _Hashtable::iterator iterator;
121  typedef typename _Hashtable::const_iterator const_iterator;
122  typedef typename _Hashtable::local_iterator local_iterator;
123  typedef typename _Hashtable::const_local_iterator const_local_iterator;
124  typedef typename _Hashtable::size_type size_type;
125  typedef typename _Hashtable::difference_type difference_type;
126  //@}
127 
128  //construct/destroy/copy
129 
130  /**
131  * @brief Default constructor creates no elements.
132  * @param __n Initial number of buckets.
133  * @param __hf A hash functor.
134  * @param __eql A key equality functor.
135  * @param __a An allocator object.
136  */
137  explicit
138  unordered_map(size_type __n = 10,
139  const hasher& __hf = hasher(),
140  const key_equal& __eql = key_equal(),
141  const allocator_type& __a = allocator_type())
142  : _M_h(__n, __hf, __eql, __a)
143  { }
144 
145  /**
146  * @brief Builds an %unordered_map from a range.
147  * @param __first An input iterator.
148  * @param __last An input iterator.
149  * @param __n Minimal initial number of buckets.
150  * @param __hf A hash functor.
151  * @param __eql A key equality functor.
152  * @param __a An allocator object.
153  *
154  * Create an %unordered_map consisting of copies of the elements from
155  * [__first,__last). This is linear in N (where N is
156  * distance(__first,__last)).
157  */
158  template<typename _InputIterator>
159  unordered_map(_InputIterator __f, _InputIterator __l,
160  size_type __n = 0,
161  const hasher& __hf = hasher(),
162  const key_equal& __eql = key_equal(),
163  const allocator_type& __a = allocator_type())
164  : _M_h(__f, __l, __n, __hf, __eql, __a)
165  { }
166 
167  /// Copy constructor.
168  unordered_map(const unordered_map&) = default;
169 
170  /// Move constructor.
171  unordered_map(unordered_map&&) = default;
172 
173  /**
174  * @brief Builds an %unordered_map from an initializer_list.
175  * @param __l An initializer_list.
176  * @param __n Minimal initial number of buckets.
177  * @param __hf A hash functor.
178  * @param __eql A key equality functor.
179  * @param __a An allocator object.
180  *
181  * Create an %unordered_map consisting of copies of the elements in the
182  * list. This is linear in N (where N is @a __l.size()).
183  */
184  unordered_map(initializer_list<value_type> __l,
185  size_type __n = 0,
186  const hasher& __hf = hasher(),
187  const key_equal& __eql = key_equal(),
188  const allocator_type& __a = allocator_type())
189  : _M_h(__l, __n, __hf, __eql, __a)
190  { }
191 
192  /// Copy assignment operator.
194  operator=(const unordered_map&) = default;
195 
196  /// Move assignment operator.
198  operator=(unordered_map&&) = default;
199 
200  /**
201  * @brief %Unordered_map list assignment operator.
202  * @param __l An initializer_list.
203  *
204  * This function fills an %unordered_map with copies of the elements in
205  * the initializer list @a __l.
206  *
207  * Note that the assignment completely changes the %unordered_map and
208  * that the resulting %unordered_map's size is the same as the number
209  * of elements assigned. Old data may be lost.
210  */
212  operator=(initializer_list<value_type> __l)
213  {
214  _M_h = __l;
215  return *this;
216  }
217 
218  /// Returns the allocator object with which the %unordered_map was
219  /// constructed.
220  allocator_type
221  get_allocator() const noexcept
222  { return _M_h.get_allocator(); }
223 
224  // size and capacity:
225 
226  /// Returns true if the %unordered_map is empty.
227  bool
228  empty() const noexcept
229  { return _M_h.empty(); }
230 
231  /// Returns the size of the %unordered_map.
232  size_type
233  size() const noexcept
234  { return _M_h.size(); }
235 
236  /// Returns the maximum size of the %unordered_map.
237  size_type
238  max_size() const noexcept
239  { return _M_h.max_size(); }
240 
241  // iterators.
242 
243  /**
244  * Returns a read/write iterator that points to the first element in the
245  * %unordered_map.
246  */
247  iterator
248  begin() noexcept
249  { return _M_h.begin(); }
250 
251  //@{
252  /**
253  * Returns a read-only (constant) iterator that points to the first
254  * element in the %unordered_map.
255  */
256  const_iterator
257  begin() const noexcept
258  { return _M_h.begin(); }
259 
260  const_iterator
261  cbegin() const noexcept
262  { return _M_h.begin(); }
263  //@}
264 
265  /**
266  * Returns a read/write iterator that points one past the last element in
267  * the %unordered_map.
268  */
269  iterator
270  end() noexcept
271  { return _M_h.end(); }
272 
273  //@{
274  /**
275  * Returns a read-only (constant) iterator that points one past the last
276  * element in the %unordered_map.
277  */
278  const_iterator
279  end() const noexcept
280  { return _M_h.end(); }
281 
282  const_iterator
283  cend() const noexcept
284  { return _M_h.end(); }
285  //@}
286 
287  // modifiers.
288 
289  /**
290  * @brief Attempts to build and insert a std::pair into the %unordered_map.
291  *
292  * @param __args Arguments used to generate a new pair instance (see
293  * std::piecewise_contruct for passing arguments to each
294  * part of the pair constructor).
295  *
296  * @return A pair, of which the first element is an iterator that points
297  * to the possibly inserted pair, and the second is a bool that
298  * is true if the pair was actually inserted.
299  *
300  * This function attempts to build and insert a (key, value) %pair into
301  * the %unordered_map.
302  * An %unordered_map relies on unique keys and thus a %pair is only
303  * inserted if its first element (the key) is not already present in the
304  * %unordered_map.
305  *
306  * Insertion requires amortized constant time.
307  */
308  template<typename... _Args>
310  emplace(_Args&&... __args)
311  { return _M_h.emplace(std::forward<_Args>(__args)...); }
312 
313  /**
314  * @brief Attempts to build and insert a std::pair into the %unordered_map.
315  *
316  * @param __pos An iterator that serves as a hint as to where the pair
317  * should be inserted.
318  * @param __args Arguments used to generate a new pair instance (see
319  * std::piecewise_contruct for passing arguments to each
320  * part of the pair constructor).
321  * @return An iterator that points to the element with key of the
322  * std::pair built from @a __args (may or may not be that
323  * std::pair).
324  *
325  * This function is not concerned about whether the insertion took place,
326  * and thus does not return a boolean like the single-argument emplace()
327  * does.
328  * Note that the first parameter is only a hint and can potentially
329  * improve the performance of the insertion process. A bad hint would
330  * cause no gains in efficiency.
331  *
332  * See
333  * http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt07ch17.html
334  * for more on @a hinting.
335  *
336  * Insertion requires amortized constant time.
337  */
338  template<typename... _Args>
339  iterator
340  emplace_hint(const_iterator __pos, _Args&&... __args)
341  { return _M_h.emplace_hint(__pos, std::forward<_Args>(__args)...); }
342 
343  //@{
344  /**
345  * @brief Attempts to insert a std::pair into the %unordered_map.
346 
347  * @param __x Pair to be inserted (see std::make_pair for easy
348  * creation of pairs).
349  *
350  * @return A pair, of which the first element is an iterator that
351  * points to the possibly inserted pair, and the second is
352  * a bool that is true if the pair was actually inserted.
353  *
354  * This function attempts to insert a (key, value) %pair into the
355  * %unordered_map. An %unordered_map relies on unique keys and thus a
356  * %pair is only inserted if its first element (the key) is not already
357  * present in the %unordered_map.
358  *
359  * Insertion requires amortized constant time.
360  */
362  insert(const value_type& __x)
363  { return _M_h.insert(__x); }
364 
365  template<typename _Pair, typename = typename
366  std::enable_if<std::is_constructible<value_type,
367  _Pair&&>::value>::type>
369  insert(_Pair&& __x)
370  { return _M_h.insert(std::forward<_Pair>(__x)); }
371  //@}
372 
373  //@{
374  /**
375  * @brief Attempts to insert a std::pair into the %unordered_map.
376  * @param __hint An iterator that serves as a hint as to where the
377  * pair should be inserted.
378  * @param __x Pair to be inserted (see std::make_pair for easy creation
379  * of pairs).
380  * @return An iterator that points to the element with key of
381  * @a __x (may or may not be the %pair passed in).
382  *
383  * This function is not concerned about whether the insertion took place,
384  * and thus does not return a boolean like the single-argument insert()
385  * does. Note that the first parameter is only a hint and can
386  * potentially improve the performance of the insertion process. A bad
387  * hint would cause no gains in efficiency.
388  *
389  * See
390  * http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt07ch17.html
391  * for more on @a hinting.
392  *
393  * Insertion requires amortized constant time.
394  */
395  iterator
396  insert(const_iterator __hint, const value_type& __x)
397  { return _M_h.insert(__hint, __x); }
398 
399  template<typename _Pair, typename = typename
400  std::enable_if<std::is_constructible<value_type,
401  _Pair&&>::value>::type>
402  iterator
403  insert(const_iterator __hint, _Pair&& __x)
404  { return _M_h.insert(__hint, std::forward<_Pair>(__x)); }
405  //@}
406 
407  /**
408  * @brief A template function that attempts to insert a range of
409  * elements.
410  * @param __first Iterator pointing to the start of the range to be
411  * inserted.
412  * @param __last Iterator pointing to the end of the range.
413  *
414  * Complexity similar to that of the range constructor.
415  */
416  template<typename _InputIterator>
417  void
418  insert(_InputIterator __first, _InputIterator __last)
419  { _M_h.insert(__first, __last); }
420 
421  /**
422  * @brief Attempts to insert a list of elements into the %unordered_map.
423  * @param __l A std::initializer_list<value_type> of elements
424  * to be inserted.
425  *
426  * Complexity similar to that of the range constructor.
427  */
428  void
429  insert(initializer_list<value_type> __l)
430  { _M_h.insert(__l); }
431 
432  //@{
433  /**
434  * @brief Erases an element from an %unordered_map.
435  * @param __position An iterator pointing to the element to be erased.
436  * @return An iterator pointing to the element immediately following
437  * @a __position prior to the element being erased. If no such
438  * element exists, end() is returned.
439  *
440  * This function erases an element, pointed to by the given iterator,
441  * from an %unordered_map.
442  * Note that this function only erases the element, and that if the
443  * element is itself a pointer, the pointed-to memory is not touched in
444  * any way. Managing the pointer is the user's responsibility.
445  */
446  iterator
447  erase(const_iterator __position)
448  { return _M_h.erase(__position); }
449 
450  // LWG 2059.
451  iterator
452  erase(iterator __it)
453  { return _M_h.erase(__it); }
454  //@}
455 
456  /**
457  * @brief Erases elements according to the provided key.
458  * @param __x Key of element to be erased.
459  * @return The number of elements erased.
460  *
461  * This function erases all the elements located by the given key from
462  * an %unordered_map. For an %unordered_map the result of this function
463  * can only be 0 (not present) or 1 (present).
464  * Note that this function only erases the element, and that if the
465  * element is itself a pointer, the pointed-to memory is not touched in
466  * any way. Managing the pointer is the user's responsibility.
467  */
468  size_type
469  erase(const key_type& __x)
470  { return _M_h.erase(__x); }
471 
472  /**
473  * @brief Erases a [__first,__last) range of elements from an
474  * %unordered_map.
475  * @param __first Iterator pointing to the start of the range to be
476  * erased.
477  * @param __last Iterator pointing to the end of the range to
478  * be erased.
479  * @return The iterator @a __last.
480  *
481  * This function erases a sequence of elements from an %unordered_map.
482  * Note that this function only erases the elements, and that if
483  * the element is itself a pointer, the pointed-to memory is not touched
484  * in any way. Managing the pointer is the user's responsibility.
485  */
486  iterator
487  erase(const_iterator __first, const_iterator __last)
488  { return _M_h.erase(__first, __last); }
489 
490  /**
491  * Erases all elements in an %unordered_map.
492  * Note that this function only erases the elements, and that if the
493  * elements themselves are pointers, the pointed-to memory is not touched
494  * in any way. Managing the pointer is the user's responsibility.
495  */
496  void
497  clear() noexcept
498  { _M_h.clear(); }
499 
500  /**
501  * @brief Swaps data with another %unordered_map.
502  * @param __x An %unordered_map of the same element and allocator
503  * types.
504  *
505  * This exchanges the elements between two %unordered_map in constant time.
506  * Note that the global std::swap() function is specialized such that
507  * std::swap(m1,m2) will feed to this function.
508  */
509  void
511  { _M_h.swap(__x._M_h); }
512 
513  // observers.
514 
515  /// Returns the hash functor object with which the %unordered_map was
516  /// constructed.
517  hasher
519  { return _M_h.hash_function(); }
520 
521  /// Returns the key comparison object with which the %unordered_map was
522  /// constructed.
523  key_equal
524  key_eq() const
525  { return _M_h.key_eq(); }
526 
527  // lookup.
528 
529  //@{
530  /**
531  * @brief Tries to locate an element in an %unordered_map.
532  * @param __x Key to be located.
533  * @return Iterator pointing to sought-after element, or end() if not
534  * found.
535  *
536  * This function takes a key and tries to locate the element with which
537  * the key matches. If successful the function returns an iterator
538  * pointing to the sought after element. If unsuccessful it returns the
539  * past-the-end ( @c end() ) iterator.
540  */
541  iterator
542  find(const key_type& __x)
543  { return _M_h.find(__x); }
544 
545  const_iterator
546  find(const key_type& __x) const
547  { return _M_h.find(__x); }
548  //@}
549 
550  /**
551  * @brief Finds the number of elements.
552  * @param __x Key to count.
553  * @return Number of elements with specified key.
554  *
555  * This function only makes sense for %unordered_multimap; for
556  * %unordered_map the result will either be 0 (not present) or 1
557  * (present).
558  */
559  size_type
560  count(const key_type& __x) const
561  { return _M_h.count(__x); }
562 
563  //@{
564  /**
565  * @brief Finds a subsequence matching given key.
566  * @param __x Key to be located.
567  * @return Pair of iterators that possibly points to the subsequence
568  * matching given key.
569  *
570  * This function probably only makes sense for %unordered_multimap.
571  */
573  equal_range(const key_type& __x)
574  { return _M_h.equal_range(__x); }
575 
577  equal_range(const key_type& __x) const
578  { return _M_h.equal_range(__x); }
579  //@}
580 
581  //@{
582  /**
583  * @brief Subscript ( @c [] ) access to %unordered_map data.
584  * @param __k The key for which data should be retrieved.
585  * @return A reference to the data of the (key,data) %pair.
586  *
587  * Allows for easy lookup with the subscript ( @c [] )operator. Returns
588  * data associated with the key specified in subscript. If the key does
589  * not exist, a pair with that key is created using default values, which
590  * is then returned.
591  *
592  * Lookup requires constant time.
593  */
594  mapped_type&
595  operator[](const key_type& __k)
596  { return _M_h[__k]; }
597 
598  mapped_type&
599  operator[](key_type&& __k)
600  { return _M_h[std::move(__k)]; }
601  //@}
602 
603  //@{
604  /**
605  * @brief Access to %unordered_map data.
606  * @param __k The key for which data should be retrieved.
607  * @return A reference to the data whose key is equal to @a __k, if
608  * such a data is present in the %unordered_map.
609  * @throw std::out_of_range If no such data is present.
610  */
611  mapped_type&
612  at(const key_type& __k)
613  { return _M_h.at(__k); }
614 
615  const mapped_type&
616  at(const key_type& __k) const
617  { return _M_h.at(__k); }
618  //@}
619 
620  // bucket interface.
621 
622  /// Returns the number of buckets of the %unordered_map.
623  size_type
624  bucket_count() const noexcept
625  { return _M_h.bucket_count(); }
626 
627  /// Returns the maximum number of buckets of the %unordered_map.
628  size_type
629  max_bucket_count() const noexcept
630  { return _M_h.max_bucket_count(); }
631 
632  /*
633  * @brief Returns the number of elements in a given bucket.
634  * @param __n A bucket index.
635  * @return The number of elements in the bucket.
636  */
637  size_type
638  bucket_size(size_type __n) const
639  { return _M_h.bucket_size(__n); }
640 
641  /*
642  * @brief Returns the bucket index of a given element.
643  * @param __key A key instance.
644  * @return The key bucket index.
645  */
646  size_type
647  bucket(const key_type& __key) const
648  { return _M_h.bucket(__key); }
649 
650  /**
651  * @brief Returns a read/write iterator pointing to the first bucket
652  * element.
653  * @param __n The bucket index.
654  * @return A read/write local iterator.
655  */
656  local_iterator
657  begin(size_type __n)
658  { return _M_h.begin(__n); }
659 
660  //@{
661  /**
662  * @brief Returns a read-only (constant) iterator pointing to the first
663  * bucket element.
664  * @param __n The bucket index.
665  * @return A read-only local iterator.
666  */
667  const_local_iterator
668  begin(size_type __n) const
669  { return _M_h.begin(__n); }
670 
671  const_local_iterator
672  cbegin(size_type __n) const
673  { return _M_h.cbegin(__n); }
674  //@}
675 
676  /**
677  * @brief Returns a read/write iterator pointing to one past the last
678  * bucket elements.
679  * @param __n The bucket index.
680  * @return A read/write local iterator.
681  */
682  local_iterator
683  end(size_type __n)
684  { return _M_h.end(__n); }
685 
686  //@{
687  /**
688  * @brief Returns a read-only (constant) iterator pointing to one past
689  * the last bucket elements.
690  * @param __n The bucket index.
691  * @return A read-only local iterator.
692  */
693  const_local_iterator
694  end(size_type __n) const
695  { return _M_h.end(__n); }
696 
697  const_local_iterator
698  cend(size_type __n) const
699  { return _M_h.cend(__n); }
700  //@}
701 
702  // hash policy.
703 
704  /// Returns the average number of elements per bucket.
705  float
706  load_factor() const noexcept
707  { return _M_h.load_factor(); }
708 
709  /// Returns a positive number that the %unordered_map tries to keep the
710  /// load factor less than or equal to.
711  float
712  max_load_factor() const noexcept
713  { return _M_h.max_load_factor(); }
714 
715  /**
716  * @brief Change the %unordered_map maximum load factor.
717  * @param __z The new maximum load factor.
718  */
719  void
720  max_load_factor(float __z)
721  { _M_h.max_load_factor(__z); }
722 
723  /**
724  * @brief May rehash the %unordered_map.
725  * @param __n The new number of buckets.
726  *
727  * Rehash will occur only if the new number of buckets respect the
728  * %unordered_map maximum load factor.
729  */
730  void
731  rehash(size_type __n)
732  { _M_h.rehash(__n); }
733 
734  /**
735  * @brief Prepare the %unordered_map for a specified number of
736  * elements.
737  * @param __n Number of elements required.
738  *
739  * Same as rehash(ceil(n / max_load_factor())).
740  */
741  void
742  reserve(size_type __n)
743  { _M_h.reserve(__n); }
744 
745  template<typename _Key1, typename _Tp1, typename _Hash1, typename _Pred1,
746  typename _Alloc1>
747  friend bool
750  };
751 
752  /**
753  * @brief A standard container composed of equivalent keys
754  * (possibly containing multiple of each key value) that associates
755  * values of another type with the keys.
756  *
757  * @ingroup unordered_associative_containers
758  *
759  * @tparam _Key Type of key objects.
760  * @tparam _Tp Type of mapped objects.
761  * @tparam _Hash Hashing function object type, defaults to hash<_Value>.
762  * @tparam _Pred Predicate function object type, defaults
763  * to equal_to<_Value>.
764  * @tparam _Alloc Allocator type, defaults to allocator<_Key>.
765  *
766  * Meets the requirements of a <a href="tables.html#65">container</a>, and
767  * <a href="tables.html#xx">unordered associative container</a>
768  *
769  * The resulting value type of the container is std::pair<const _Key, _Tp>.
770  *
771  * Base is _Hashtable, dispatched at compile time via template
772  * alias __ummap_hashtable.
773  */
774  template<class _Key, class _Tp,
775  class _Hash = hash<_Key>,
776  class _Pred = std::equal_to<_Key>,
778  class unordered_multimap : __check_copy_constructible<_Alloc>
779  {
781  _Hashtable _M_h;
782 
783  public:
784  // typedefs:
785  //@{
786  /// Public typedefs.
787  typedef typename _Hashtable::key_type key_type;
788  typedef typename _Hashtable::value_type value_type;
789  typedef typename _Hashtable::mapped_type mapped_type;
790  typedef typename _Hashtable::hasher hasher;
791  typedef typename _Hashtable::key_equal key_equal;
792  typedef typename _Hashtable::allocator_type allocator_type;
793  //@}
794 
795  //@{
796  /// Iterator-related typedefs.
797  typedef typename allocator_type::pointer pointer;
798  typedef typename allocator_type::const_pointer const_pointer;
799  typedef typename allocator_type::reference reference;
800  typedef typename allocator_type::const_reference const_reference;
801  typedef typename _Hashtable::iterator iterator;
802  typedef typename _Hashtable::const_iterator const_iterator;
803  typedef typename _Hashtable::local_iterator local_iterator;
804  typedef typename _Hashtable::const_local_iterator const_local_iterator;
805  typedef typename _Hashtable::size_type size_type;
806  typedef typename _Hashtable::difference_type difference_type;
807  //@}
808 
809  //construct/destroy/copy
810 
811  /**
812  * @brief Default constructor creates no elements.
813  * @param __n Initial number of buckets.
814  * @param __hf A hash functor.
815  * @param __eql A key equality functor.
816  * @param __a An allocator object.
817  */
818  explicit
819  unordered_multimap(size_type __n = 10,
820  const hasher& __hf = hasher(),
821  const key_equal& __eql = key_equal(),
822  const allocator_type& __a = allocator_type())
823  : _M_h(__n, __hf, __eql, __a)
824  { }
825 
826  /**
827  * @brief Builds an %unordered_multimap from a range.
828  * @param __first An input iterator.
829  * @param __last An input iterator.
830  * @param __n Minimal initial number of buckets.
831  * @param __hf A hash functor.
832  * @param __eql A key equality functor.
833  * @param __a An allocator object.
834  *
835  * Create an %unordered_multimap consisting of copies of the elements
836  * from [__first,__last). This is linear in N (where N is
837  * distance(__first,__last)).
838  */
839  template<typename _InputIterator>
840  unordered_multimap(_InputIterator __f, _InputIterator __l,
841  size_type __n = 0,
842  const hasher& __hf = hasher(),
843  const key_equal& __eql = key_equal(),
844  const allocator_type& __a = allocator_type())
845  : _M_h(__f, __l, __n, __hf, __eql, __a)
846  { }
847 
848  /// Copy constructor.
849  unordered_multimap(const unordered_multimap&) = default;
850 
851  /// Move constructor.
853 
854  /**
855  * @brief Builds an %unordered_multimap from an initializer_list.
856  * @param __l An initializer_list.
857  * @param __n Minimal initial number of buckets.
858  * @param __hf A hash functor.
859  * @param __eql A key equality functor.
860  * @param __a An allocator object.
861  *
862  * Create an %unordered_multimap consisting of copies of the elements in
863  * the list. This is linear in N (where N is @a __l.size()).
864  */
865  unordered_multimap(initializer_list<value_type> __l,
866  size_type __n = 0,
867  const hasher& __hf = hasher(),
868  const key_equal& __eql = key_equal(),
869  const allocator_type& __a = allocator_type())
870  : _M_h(__l, __n, __hf, __eql, __a)
871  { }
872 
873  /// Copy assignment operator.
875  operator=(const unordered_multimap&) = default;
876 
877  /// Move assignment operator.
879  operator=(unordered_multimap&&) = default;
880 
881  /**
882  * @brief %Unordered_multimap list assignment operator.
883  * @param __l An initializer_list.
884  *
885  * This function fills an %unordered_multimap with copies of the elements
886  * in the initializer list @a __l.
887  *
888  * Note that the assignment completely changes the %unordered_multimap
889  * and that the resulting %unordered_multimap's size is the same as the
890  * number of elements assigned. Old data may be lost.
891  */
893  operator=(initializer_list<value_type> __l)
894  {
895  _M_h = __l;
896  return *this;
897  }
898 
899  /// Returns the allocator object with which the %unordered_multimap was
900  /// constructed.
901  allocator_type
902  get_allocator() const noexcept
903  { return _M_h.get_allocator(); }
904 
905  // size and capacity:
906 
907  /// Returns true if the %unordered_multimap is empty.
908  bool
909  empty() const noexcept
910  { return _M_h.empty(); }
911 
912  /// Returns the size of the %unordered_multimap.
913  size_type
914  size() const noexcept
915  { return _M_h.size(); }
916 
917  /// Returns the maximum size of the %unordered_multimap.
918  size_type
919  max_size() const noexcept
920  { return _M_h.max_size(); }
921 
922  // iterators.
923 
924  /**
925  * Returns a read/write iterator that points to the first element in the
926  * %unordered_multimap.
927  */
928  iterator
929  begin() noexcept
930  { return _M_h.begin(); }
931 
932  //@{
933  /**
934  * Returns a read-only (constant) iterator that points to the first
935  * element in the %unordered_multimap.
936  */
937  const_iterator
938  begin() const noexcept
939  { return _M_h.begin(); }
940 
941  const_iterator
942  cbegin() const noexcept
943  { return _M_h.begin(); }
944  //@}
945 
946  /**
947  * Returns a read/write iterator that points one past the last element in
948  * the %unordered_multimap.
949  */
950  iterator
951  end() noexcept
952  { return _M_h.end(); }
953 
954  //@{
955  /**
956  * Returns a read-only (constant) iterator that points one past the last
957  * element in the %unordered_multimap.
958  */
959  const_iterator
960  end() const noexcept
961  { return _M_h.end(); }
962 
963  const_iterator
964  cend() const noexcept
965  { return _M_h.end(); }
966  //@}
967 
968  // modifiers.
969 
970  /**
971  * @brief Attempts to build and insert a std::pair into the
972  * %unordered_multimap.
973  *
974  * @param __args Arguments used to generate a new pair instance (see
975  * std::piecewise_contruct for passing arguments to each
976  * part of the pair constructor).
977  *
978  * @return An iterator that points to the inserted pair.
979  *
980  * This function attempts to build and insert a (key, value) %pair into
981  * the %unordered_multimap.
982  *
983  * Insertion requires amortized constant time.
984  */
985  template<typename... _Args>
986  iterator
987  emplace(_Args&&... __args)
988  { return _M_h.emplace(std::forward<_Args>(__args)...); }
989 
990  /**
991  * @brief Attempts to build and insert a std::pair into the %unordered_multimap.
992  *
993  * @param __pos An iterator that serves as a hint as to where the pair
994  * should be inserted.
995  * @param __args Arguments used to generate a new pair instance (see
996  * std::piecewise_contruct for passing arguments to each
997  * part of the pair constructor).
998  * @return An iterator that points to the element with key of the
999  * std::pair built from @a __args.
1000  *
1001  * Note that the first parameter is only a hint and can potentially
1002  * improve the performance of the insertion process. A bad hint would
1003  * cause no gains in efficiency.
1004  *
1005  * See
1006  * http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt07ch17.html
1007  * for more on @a hinting.
1008  *
1009  * Insertion requires amortized constant time.
1010  */
1011  template<typename... _Args>
1012  iterator
1013  emplace_hint(const_iterator __pos, _Args&&... __args)
1014  { return _M_h.emplace_hint(__pos, std::forward<_Args>(__args)...); }
1015 
1016  //@{
1017  /**
1018  * @brief Inserts a std::pair into the %unordered_multimap.
1019  * @param __x Pair to be inserted (see std::make_pair for easy
1020  * creation of pairs).
1021  *
1022  * @return An iterator that points to the inserted pair.
1023  *
1024  * Insertion requires amortized constant time.
1025  */
1026  iterator
1027  insert(const value_type& __x)
1028  { return _M_h.insert(__x); }
1029 
1030  template<typename _Pair, typename = typename
1031  std::enable_if<std::is_constructible<value_type,
1032  _Pair&&>::value>::type>
1033  iterator
1034  insert(_Pair&& __x)
1035  { return _M_h.insert(std::forward<_Pair>(__x)); }
1036  //@}
1037 
1038  //@{
1039  /**
1040  * @brief Inserts a std::pair into the %unordered_multimap.
1041  * @param __hint An iterator that serves as a hint as to where the
1042  * pair should be inserted.
1043  * @param __x Pair to be inserted (see std::make_pair for easy creation
1044  * of pairs).
1045  * @return An iterator that points to the element with key of
1046  * @a __x (may or may not be the %pair passed in).
1047  *
1048  * Note that the first parameter is only a hint and can potentially
1049  * improve the performance of the insertion process. A bad hint would
1050  * cause no gains in efficiency.
1051  *
1052  * See
1053  * http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt07ch17.html
1054  * for more on @a hinting.
1055  *
1056  * Insertion requires amortized constant time.
1057  */
1058  iterator
1059  insert(const_iterator __hint, const value_type& __x)
1060  { return _M_h.insert(__hint, __x); }
1061 
1062  template<typename _Pair, typename = typename
1063  std::enable_if<std::is_constructible<value_type,
1064  _Pair&&>::value>::type>
1065  iterator
1066  insert(const_iterator __hint, _Pair&& __x)
1067  { return _M_h.insert(__hint, std::forward<_Pair>(__x)); }
1068  //@}
1069 
1070  /**
1071  * @brief A template function that attempts to insert a range of
1072  * elements.
1073  * @param __first Iterator pointing to the start of the range to be
1074  * inserted.
1075  * @param __last Iterator pointing to the end of the range.
1076  *
1077  * Complexity similar to that of the range constructor.
1078  */
1079  template<typename _InputIterator>
1080  void
1081  insert(_InputIterator __first, _InputIterator __last)
1082  { _M_h.insert(__first, __last); }
1083 
1084  /**
1085  * @brief Attempts to insert a list of elements into the
1086  * %unordered_multimap.
1087  * @param __l A std::initializer_list<value_type> of elements
1088  * to be inserted.
1089  *
1090  * Complexity similar to that of the range constructor.
1091  */
1092  void
1093  insert(initializer_list<value_type> __l)
1094  { _M_h.insert(__l); }
1095 
1096  //@{
1097  /**
1098  * @brief Erases an element from an %unordered_multimap.
1099  * @param __position An iterator pointing to the element to be erased.
1100  * @return An iterator pointing to the element immediately following
1101  * @a __position prior to the element being erased. If no such
1102  * element exists, end() is returned.
1103  *
1104  * This function erases an element, pointed to by the given iterator,
1105  * from an %unordered_multimap.
1106  * Note that this function only erases the element, and that if the
1107  * element is itself a pointer, the pointed-to memory is not touched in
1108  * any way. Managing the pointer is the user's responsibility.
1109  */
1110  iterator
1111  erase(const_iterator __position)
1112  { return _M_h.erase(__position); }
1113 
1114  // LWG 2059.
1115  iterator
1116  erase(iterator __it)
1117  { return _M_h.erase(__it); }
1118  //@}
1119 
1120  /**
1121  * @brief Erases elements according to the provided key.
1122  * @param __x Key of elements to be erased.
1123  * @return The number of elements erased.
1124  *
1125  * This function erases all the elements located by the given key from
1126  * an %unordered_multimap.
1127  * Note that this function only erases the element, and that if the
1128  * element is itself a pointer, the pointed-to memory is not touched in
1129  * any way. Managing the pointer is the user's responsibility.
1130  */
1131  size_type
1132  erase(const key_type& __x)
1133  { return _M_h.erase(__x); }
1134 
1135  /**
1136  * @brief Erases a [__first,__last) range of elements from an
1137  * %unordered_multimap.
1138  * @param __first Iterator pointing to the start of the range to be
1139  * erased.
1140  * @param __last Iterator pointing to the end of the range to
1141  * be erased.
1142  * @return The iterator @a __last.
1143  *
1144  * This function erases a sequence of elements from an
1145  * %unordered_multimap.
1146  * Note that this function only erases the elements, and that if
1147  * the element is itself a pointer, the pointed-to memory is not touched
1148  * in any way. Managing the pointer is the user's responsibility.
1149  */
1150  iterator
1151  erase(const_iterator __first, const_iterator __last)
1152  { return _M_h.erase(__first, __last); }
1153 
1154  /**
1155  * Erases all elements in an %unordered_multimap.
1156  * Note that this function only erases the elements, and that if the
1157  * elements themselves are pointers, the pointed-to memory is not touched
1158  * in any way. Managing the pointer is the user's responsibility.
1159  */
1160  void
1161  clear() noexcept
1162  { _M_h.clear(); }
1163 
1164  /**
1165  * @brief Swaps data with another %unordered_multimap.
1166  * @param __x An %unordered_multimap of the same element and allocator
1167  * types.
1168  *
1169  * This exchanges the elements between two %unordered_multimap in
1170  * constant time.
1171  * Note that the global std::swap() function is specialized such that
1172  * std::swap(m1,m2) will feed to this function.
1173  */
1174  void
1176  { _M_h.swap(__x._M_h); }
1177 
1178  // observers.
1179 
1180  /// Returns the hash functor object with which the %unordered_multimap
1181  /// was constructed.
1182  hasher
1184  { return _M_h.hash_function(); }
1185 
1186  /// Returns the key comparison object with which the %unordered_multimap
1187  /// was constructed.
1188  key_equal
1189  key_eq() const
1190  { return _M_h.key_eq(); }
1191 
1192  // lookup.
1193 
1194  //@{
1195  /**
1196  * @brief Tries to locate an element in an %unordered_multimap.
1197  * @param __x Key to be located.
1198  * @return Iterator pointing to sought-after element, or end() if not
1199  * found.
1200  *
1201  * This function takes a key and tries to locate the element with which
1202  * the key matches. If successful the function returns an iterator
1203  * pointing to the sought after element. If unsuccessful it returns the
1204  * past-the-end ( @c end() ) iterator.
1205  */
1206  iterator
1207  find(const key_type& __x)
1208  { return _M_h.find(__x); }
1209 
1210  const_iterator
1211  find(const key_type& __x) const
1212  { return _M_h.find(__x); }
1213  //@}
1214 
1215  /**
1216  * @brief Finds the number of elements.
1217  * @param __x Key to count.
1218  * @return Number of elements with specified key.
1219  */
1220  size_type
1221  count(const key_type& __x) const
1222  { return _M_h.count(__x); }
1223 
1224  //@{
1225  /**
1226  * @brief Finds a subsequence matching given key.
1227  * @param __x Key to be located.
1228  * @return Pair of iterators that possibly points to the subsequence
1229  * matching given key.
1230  */
1232  equal_range(const key_type& __x)
1233  { return _M_h.equal_range(__x); }
1234 
1236  equal_range(const key_type& __x) const
1237  { return _M_h.equal_range(__x); }
1238  //@}
1239 
1240  // bucket interface.
1241 
1242  /// Returns the number of buckets of the %unordered_multimap.
1243  size_type
1244  bucket_count() const noexcept
1245  { return _M_h.bucket_count(); }
1246 
1247  /// Returns the maximum number of buckets of the %unordered_multimap.
1248  size_type
1249  max_bucket_count() const noexcept
1250  { return _M_h.max_bucket_count(); }
1251 
1252  /*
1253  * @brief Returns the number of elements in a given bucket.
1254  * @param __n A bucket index.
1255  * @return The number of elements in the bucket.
1256  */
1257  size_type
1258  bucket_size(size_type __n) const
1259  { return _M_h.bucket_size(__n); }
1260 
1261  /*
1262  * @brief Returns the bucket index of a given element.
1263  * @param __key A key instance.
1264  * @return The key bucket index.
1265  */
1266  size_type
1267  bucket(const key_type& __key) const
1268  { return _M_h.bucket(__key); }
1269 
1270  /**
1271  * @brief Returns a read/write iterator pointing to the first bucket
1272  * element.
1273  * @param __n The bucket index.
1274  * @return A read/write local iterator.
1275  */
1276  local_iterator
1277  begin(size_type __n)
1278  { return _M_h.begin(__n); }
1279 
1280  //@{
1281  /**
1282  * @brief Returns a read-only (constant) iterator pointing to the first
1283  * bucket element.
1284  * @param __n The bucket index.
1285  * @return A read-only local iterator.
1286  */
1287  const_local_iterator
1288  begin(size_type __n) const
1289  { return _M_h.begin(__n); }
1290 
1291  const_local_iterator
1292  cbegin(size_type __n) const
1293  { return _M_h.cbegin(__n); }
1294  //@}
1295 
1296  /**
1297  * @brief Returns a read/write iterator pointing to one past the last
1298  * bucket elements.
1299  * @param __n The bucket index.
1300  * @return A read/write local iterator.
1301  */
1302  local_iterator
1303  end(size_type __n)
1304  { return _M_h.end(__n); }
1305 
1306  //@{
1307  /**
1308  * @brief Returns a read-only (constant) iterator pointing to one past
1309  * the last bucket elements.
1310  * @param __n The bucket index.
1311  * @return A read-only local iterator.
1312  */
1313  const_local_iterator
1314  end(size_type __n) const
1315  { return _M_h.end(__n); }
1316 
1317  const_local_iterator
1318  cend(size_type __n) const
1319  { return _M_h.cend(__n); }
1320  //@}
1321 
1322  // hash policy.
1323 
1324  /// Returns the average number of elements per bucket.
1325  float
1326  load_factor() const noexcept
1327  { return _M_h.load_factor(); }
1328 
1329  /// Returns a positive number that the %unordered_multimap tries to keep
1330  /// the load factor less than or equal to.
1331  float
1332  max_load_factor() const noexcept
1333  { return _M_h.max_load_factor(); }
1334 
1335  /**
1336  * @brief Change the %unordered_multimap maximum load factor.
1337  * @param __z The new maximum load factor.
1338  */
1339  void
1340  max_load_factor(float __z)
1341  { _M_h.max_load_factor(__z); }
1342 
1343  /**
1344  * @brief May rehash the %unordered_multimap.
1345  * @param __n The new number of buckets.
1346  *
1347  * Rehash will occur only if the new number of buckets respect the
1348  * %unordered_multimap maximum load factor.
1349  */
1350  void
1351  rehash(size_type __n)
1352  { _M_h.rehash(__n); }
1353 
1354  /**
1355  * @brief Prepare the %unordered_multimap for a specified number of
1356  * elements.
1357  * @param __n Number of elements required.
1358  *
1359  * Same as rehash(ceil(n / max_load_factor())).
1360  */
1361  void
1362  reserve(size_type __n)
1363  { _M_h.reserve(__n); }
1364 
1365  template<typename _Key1, typename _Tp1, typename _Hash1, typename _Pred1,
1366  typename _Alloc1>
1367  friend bool
1368  operator==(const unordered_multimap<_Key1, _Tp1,
1369  _Hash1, _Pred1, _Alloc1>&,
1370  const unordered_multimap<_Key1, _Tp1,
1371  _Hash1, _Pred1, _Alloc1>&);
1372  };
1373 
1374  template<class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
1375  inline void
1378  { __x.swap(__y); }
1379 
1380  template<class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
1381  inline void
1384  { __x.swap(__y); }
1385 
1386  template<class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
1387  inline bool
1388  operator==(const unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __x,
1390  { return __x._M_h._M_equal(__y._M_h); }
1391 
1392  template<class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
1393  inline bool
1394  operator!=(const unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __x,
1396  { return !(__x == __y); }
1397 
1398  template<class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
1399  inline bool
1402  { return __x._M_h._M_equal(__y._M_h); }
1403 
1404  template<class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
1405  inline bool
1408  { return !(__x == __y); }
1409 
1410 _GLIBCXX_END_NAMESPACE_CONTAINER
1411 } // namespace std
1412 
1413 #endif /* _UNORDERED_MAP_H */
size_type count(const key_type &__x) const
Finds the number of elements.
size_type max_bucket_count() const noexcept
Returns the maximum number of buckets of the unordered_map.
allocator_type::const_pointer const_pointer
Iterator-related typedefs.
mapped_type & at(const key_type &__k)
Access to unordered_map data.
const_local_iterator begin(size_type __n) const
Returns a read-only (constant) iterator pointing to the first bucket element.
iterator erase(iterator __it)
Erases an element from an unordered_map.
_Hashtable::local_iterator local_iterator
Iterator-related typedefs.
_Hashtable::size_type size_type
Iterator-related typedefs.
const mapped_type & at(const key_type &__k) const
Access to unordered_map data.
void clear() noexcept
key_equal key_eq() const
Returns the key comparison object with which the unordered_multimap was constructed.
_Hashtable::size_type size_type
Iterator-related typedefs.
void swap(unordered_multimap &__x)
Swaps data with another unordered_multimap.
iterator insert(const_iterator __hint, const value_type &__x)
Inserts a std::pair into the unordered_multimap.
allocator_type::pointer pointer
Iterator-related typedefs.
iterator begin() noexcept
_Hashtable::const_local_iterator const_local_iterator
Iterator-related typedefs.
key_equal key_eq() const
Returns the key comparison object with which the unordered_map was constructed.
void insert(initializer_list< value_type > __l)
Attempts to insert a list of elements into the unordered_map.
Default range hashing function: use division to fold a large number into the range [0...
void rehash(size_type __n)
May rehash the unordered_map.
const_local_iterator cbegin(size_type __n) const
Returns a read-only (constant) iterator pointing to the first bucket element.
size_type bucket_count() const noexcept
Returns the number of buckets of the unordered_map.
iterator find(const key_type &__x)
Tries to locate an element in an unordered_multimap.
_Hashtable::iterator iterator
Iterator-related typedefs.
unordered_map(initializer_list< value_type > __l, size_type __n=0, const hasher &__hf=hasher(), const key_equal &__eql=key_equal(), const allocator_type &__a=allocator_type())
Builds an unordered_map from an initializer_list.
ISO C++ entities toplevel namespace is std.
iterator erase(iterator __it)
Erases an element from an unordered_multimap.
const_local_iterator end(size_type __n) const
Returns a read-only (constant) iterator pointing to one past the last bucket elements.
void reserve(size_type __n)
Prepare the unordered_multimap for a specified number of elements.
size_type size() const noexcept
Returns the size of the unordered_map.
const_iterator cend() const noexcept
unordered_map & operator=(initializer_list< value_type > __l)
Unordered_map list assignment operator.
iterator erase(const_iterator __position)
Erases an element from an unordered_multimap.
allocator_type::reference reference
Iterator-related typedefs.
allocator_type::reference reference
Iterator-related typedefs.
_Hashtable::value_type value_type
Public typedefs.
_Hashtable::value_type value_type
Public typedefs.
_Hashtable::mapped_type mapped_type
Public typedefs.
size_type erase(const key_type &__x)
Erases elements according to the provided key.
_Hashtable::key_equal key_equal
Public typedefs.
float max_load_factor() const noexcept
Returns a positive number that the unordered_map tries to keep the load factor less than or equal to...
allocator_type get_allocator() const noexcept
Returns the allocator object with which the unordered_map was constructed.
iterator insert(const_iterator __hint, _Pair &&__x)
Attempts to insert a std::pair into the unordered_map.
const_iterator begin() const noexcept
iterator erase(const_iterator __position)
Erases an element from an unordered_map.
allocator_type::const_reference const_reference
Iterator-related typedefs.
float load_factor() const noexcept
Returns the average number of elements per bucket.
_Hashtable::const_iterator const_iterator
Iterator-related typedefs.
const_local_iterator cend(size_type __n) const
Returns a read-only (constant) iterator pointing to one past the last bucket elements.
void insert(_InputIterator __first, _InputIterator __last)
A template function that attempts to insert a range of elements.
unordered_multimap(initializer_list< value_type > __l, size_type __n=0, const hasher &__hf=hasher(), const key_equal &__eql=key_equal(), const allocator_type &__a=allocator_type())
Builds an unordered_multimap from an initializer_list.
unordered_multimap(_InputIterator __f, _InputIterator __l, size_type __n=0, const hasher &__hf=hasher(), const key_equal &__eql=key_equal(), const allocator_type &__a=allocator_type())
Builds an unordered_multimap from a range.
_Hashtable::difference_type difference_type
Iterator-related typedefs.
_Hashtable::iterator iterator
Iterator-related typedefs.
iterator emplace_hint(const_iterator __pos, _Args &&...__args)
Attempts to build and insert a std::pair into the unordered_multimap.
unordered_multimap & operator=(initializer_list< value_type > __l)
Unordered_multimap list assignment operator.
const_local_iterator end(size_type __n) const
Returns a read-only (constant) iterator pointing to one past the last bucket elements.
A standard container composed of equivalent keys (possibly containing multiple of each key value) tha...
size_type count(const key_type &__x) const
Finds the number of elements.
allocator_type get_allocator() const noexcept
Returns the allocator object with which the unordered_multimap was constructed.
std::pair< iterator, bool > emplace(_Args &&...__args)
Attempts to build and insert a std::pair into the unordered_map.
_Hashtable::allocator_type allocator_type
Public typedefs.
_Hashtable::key_equal key_equal
Public typedefs.
Struct holding two objects of arbitrary type.
Definition: stl_pair.h:96
const_iterator cbegin() const noexcept
local_iterator begin(size_type __n)
Returns a read/write iterator pointing to the first bucket element.
const_local_iterator cend(size_type __n) const
Returns a read-only (constant) iterator pointing to one past the last bucket elements.
local_iterator end(size_type __n)
Returns a read/write iterator pointing to one past the last bucket elements.
Default value for rehash policy. Bucket size is (usually) the smallest prime that keeps the load fact...
The standard allocator, as per [20.4].
Definition: allocator.h:92
bool empty() const noexcept
Returns true if the unordered_multimap is empty.
iterator end() noexcept
unordered_map(_InputIterator __f, _InputIterator __l, size_type __n=0, const hasher &__hf=hasher(), const key_equal &__eql=key_equal(), const allocator_type &__a=allocator_type())
Builds an unordered_map from a range.
constexpr std::remove_reference< _Tp >::type && move(_Tp &&__t) noexcept
Convert a value to an rvalue.
Definition: move.h:101
_Hashtable::key_type key_type
Public typedefs.
std::pair< const_iterator, const_iterator > equal_range(const key_type &__x) const
Finds a subsequence matching given key.
mapped_type & operator[](key_type &&__k)
Subscript ( [] ) access to unordered_map data.
_Hashtable::key_type key_type
Public typedefs.
_Hashtable::local_iterator local_iterator
Iterator-related typedefs.
iterator insert(const_iterator __hint, _Pair &&__x)
Inserts a std::pair into the unordered_multimap.
void insert(_InputIterator __first, _InputIterator __last)
A template function that attempts to insert a range of elements.
unordered_map & operator=(const unordered_map &)=default
Copy assignment operator.
size_type max_size() const noexcept
Returns the maximum size of the unordered_multimap.
local_iterator end(size_type __n)
Returns a read/write iterator pointing to one past the last bucket elements.
hasher hash_function() const
Returns the hash functor object with which the unordered_multimap was constructed.
Primary class template hash.
iterator emplace(_Args &&...__args)
Attempts to build and insert a std::pair into the unordered_multimap.
iterator insert(const_iterator __hint, const value_type &__x)
Attempts to insert a std::pair into the unordered_map.
std::pair< iterator, iterator > equal_range(const key_type &__x)
Finds a subsequence matching given key.
_Hashtable::difference_type difference_type
Iterator-related typedefs.
const_local_iterator begin(size_type __n) const
Returns a read-only (constant) iterator pointing to the first bucket element.
size_type erase(const key_type &__x)
Erases elements according to the provided key.
float load_factor() const noexcept
Returns the average number of elements per bucket.
size_type max_bucket_count() const noexcept
Returns the maximum number of buckets of the unordered_multimap.
unordered_multimap(size_type __n=10, const hasher &__hf=hasher(), const key_equal &__eql=key_equal(), const allocator_type &__a=allocator_type())
Default constructor creates no elements.
void swap(unordered_map &__x)
Swaps data with another unordered_map.
size_type bucket_count() const noexcept
Returns the number of buckets of the unordered_multimap.
A standard container composed of unique keys (containing at most one of each key value) that associat...
Definition: unordered_map.h:97
void reserve(size_type __n)
Prepare the unordered_map for a specified number of elements.
mapped_type & operator[](const key_type &__k)
Subscript ( [] ) access to unordered_map data.
const_iterator begin() const noexcept
_Hashtable::hasher hasher
Public typedefs.
void rehash(size_type __n)
May rehash the unordered_multimap.
allocator_type::const_pointer const_pointer
Iterator-related typedefs.
std::pair< iterator, bool > insert(const value_type &__x)
Attempts to insert a std::pair into the unordered_map.
Default ranged hash function H. In principle it should be a function object composed from objects of ...
const_local_iterator cbegin(size_type __n) const
Returns a read-only (constant) iterator pointing to the first bucket element.
iterator insert(const value_type &__x)
Inserts a std::pair into the unordered_multimap.
hasher hash_function() const
Returns the hash functor object with which the unordered_map was constructed.
const_iterator end() const noexcept
_Hashtable::mapped_type mapped_type
Public typedefs.
iterator erase(const_iterator __first, const_iterator __last)
Erases a [__first,__last) range of elements from an unordered_map.
std::pair< iterator, bool > insert(_Pair &&__x)
Attempts to insert a std::pair into the unordered_map.
One of the comparison functors.
Definition: stl_function.h:204
void max_load_factor(float __z)
Change the unordered_map maximum load factor.
const_iterator end() const noexcept
iterator emplace_hint(const_iterator __pos, _Args &&...__args)
Attempts to build and insert a std::pair into the unordered_map.
float max_load_factor() const noexcept
Returns a positive number that the unordered_multimap tries to keep the load factor less than or equa...
std::pair< iterator, iterator > equal_range(const key_type &__x)
Finds a subsequence matching given key.
iterator end() noexcept
const_iterator cbegin() const noexcept
iterator erase(const_iterator __first, const_iterator __last)
Erases a [__first,__last) range of elements from an unordered_multimap.
size_type size() const noexcept
Returns the size of the unordered_multimap.
std::pair< const_iterator, const_iterator > equal_range(const key_type &__x) const
Finds a subsequence matching given key.
void max_load_factor(float __z)
Change the unordered_multimap maximum load factor.
local_iterator begin(size_type __n)
Returns a read/write iterator pointing to the first bucket element.
allocator_type::pointer pointer
Iterator-related typedefs.
iterator find(const key_type &__x)
Tries to locate an element in an unordered_map.
_Hashtable::hasher hasher
Public typedefs.
const_iterator find(const key_type &__x) const
Tries to locate an element in an unordered_multimap.
_Hashtable::const_iterator const_iterator
Iterator-related typedefs.
iterator insert(_Pair &&__x)
Inserts a std::pair into the unordered_multimap.
const_iterator find(const key_type &__x) const
Tries to locate an element in an unordered_map.
unordered_map(size_type __n=10, const hasher &__hf=hasher(), const key_equal &__eql=key_equal(), const allocator_type &__a=allocator_type())
Default constructor creates no elements.
iterator begin() noexcept
_Hashtable::const_local_iterator const_local_iterator
Iterator-related typedefs.
size_type max_size() const noexcept
Returns the maximum size of the unordered_map.
bool empty() const noexcept
Returns true if the unordered_map is empty.
_Hashtable::allocator_type allocator_type
Public typedefs.
const_iterator cend() const noexcept
void insert(initializer_list< value_type > __l)
Attempts to insert a list of elements into the unordered_multimap.
allocator_type::const_reference const_reference
Iterator-related typedefs.