1 // unordered_set implementation -*- C++ -*-
3 // Copyright (C) 2010-2024 Free Software Foundation, Inc.
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 // <http://www.gnu.org/licenses/>.
25 /** @file bits/unordered_set.h
26 * This is an internal header file, included by other library headers.
27 * Do not attempt to use it directly. @headername{unordered_set}
30 #ifndef _UNORDERED_SET_H
31 #define _UNORDERED_SET_H
33 #include <bits/hashtable.h>
34 #include <bits/allocator.h>
35 #include <bits/functional_hash.h> // hash
36 #include <bits/stl_function.h> // equal_to
38 namespace std
_GLIBCXX_VISIBILITY(default)
40 _GLIBCXX_BEGIN_NAMESPACE_VERSION
41 _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
43 /// Base types for unordered_set.
45 using __uset_traits
= __detail::_Hashtable_traits
<_Cache
, true, true>;
47 template<typename _Value
,
48 typename _Hash
= hash
<_Value
>,
49 typename _Pred
= std::equal_to
<_Value
>,
50 typename _Alloc
= std::allocator
<_Value
>,
51 typename _Tr
= __uset_traits
<__cache_default
<_Value
, _Hash
>::value
>>
52 using __uset_hashtable
= _Hashtable
<_Value
, _Value
, _Alloc
,
53 __detail::_Identity
, _Pred
, _Hash
,
54 __detail::_Mod_range_hashing
,
55 __detail::_Default_ranged_hash
,
56 __detail::_Prime_rehash_policy
, _Tr
>;
58 /// Base types for unordered_multiset.
60 using __umset_traits
= __detail::_Hashtable_traits
<_Cache
, true, false>;
62 template<typename _Value
,
63 typename _Hash
= hash
<_Value
>,
64 typename _Pred
= std::equal_to
<_Value
>,
65 typename _Alloc
= std::allocator
<_Value
>,
66 typename _Tr
= __umset_traits
<__cache_default
<_Value
, _Hash
>::value
>>
67 using __umset_hashtable
= _Hashtable
<_Value
, _Value
, _Alloc
,
70 __detail::_Mod_range_hashing
,
71 __detail::_Default_ranged_hash
,
72 __detail::_Prime_rehash_policy
, _Tr
>;
74 template<class _Value
, class _Hash
, class _Pred
, class _Alloc
>
75 class unordered_multiset
;
78 * @brief A standard container composed of unique keys (containing
79 * at most one of each key value) in which the elements' keys are
80 * the elements themselves.
82 * @ingroup unordered_associative_containers
83 * @headerfile unordered_set
86 * @tparam _Value Type of key objects.
87 * @tparam _Hash Hashing function object type, defaults to hash<_Value>.
89 * @tparam _Pred Predicate function object type, defaults to
92 * @tparam _Alloc Allocator type, defaults to allocator<_Key>.
94 * Meets the requirements of a <a href="tables.html#65">container</a>, and
95 * <a href="tables.html#xx">unordered associative container</a>
97 * Base is _Hashtable, dispatched at compile time via template
98 * alias __uset_hashtable.
100 template<typename _Value
,
101 typename _Hash
= hash
<_Value
>,
102 typename _Pred
= equal_to
<_Value
>,
103 typename _Alloc
= allocator
<_Value
>>
106 typedef __uset_hashtable
<_Value
, _Hash
, _Pred
, _Alloc
> _Hashtable
;
113 typedef typename
_Hashtable::key_type key_type
;
114 typedef typename
_Hashtable::value_type value_type
;
115 typedef typename
_Hashtable::hasher hasher
;
116 typedef typename
_Hashtable::key_equal key_equal
;
117 typedef typename
_Hashtable::allocator_type allocator_type
;
121 /// Iterator-related typedefs.
122 typedef typename
_Hashtable::pointer pointer
;
123 typedef typename
_Hashtable::const_pointer const_pointer
;
124 typedef typename
_Hashtable::reference reference
;
125 typedef typename
_Hashtable::const_reference const_reference
;
126 typedef typename
_Hashtable::iterator iterator
;
127 typedef typename
_Hashtable::const_iterator const_iterator
;
128 typedef typename
_Hashtable::local_iterator local_iterator
;
129 typedef typename
_Hashtable::const_local_iterator const_local_iterator
;
130 typedef typename
_Hashtable::size_type size_type
;
131 typedef typename
_Hashtable::difference_type difference_type
;
134 #if __cplusplus > 201402L
135 using node_type
= typename
_Hashtable::node_type
;
136 using insert_return_type
= typename
_Hashtable::insert_return_type
;
139 // construct/destroy/copy
141 /// Default constructor.
142 unordered_set() = default;
145 * @brief Default constructor creates no elements.
146 * @param __n Minimal initial number of buckets.
147 * @param __hf A hash functor.
148 * @param __eql A key equality functor.
149 * @param __a An allocator object.
152 unordered_set(size_type __n
,
153 const hasher
& __hf
= hasher(),
154 const key_equal
& __eql
= key_equal(),
155 const allocator_type
& __a
= allocator_type())
156 : _M_h(__n
, __hf
, __eql
, __a
)
160 * @brief Builds an %unordered_set from a range.
161 * @param __first An input iterator.
162 * @param __last An input iterator.
163 * @param __n Minimal initial number of buckets.
164 * @param __hf A hash functor.
165 * @param __eql A key equality functor.
166 * @param __a An allocator object.
168 * Create an %unordered_set consisting of copies of the elements from
169 * [__first,__last). This is linear in N (where N is
170 * distance(__first,__last)).
172 template<typename _InputIterator
>
173 unordered_set(_InputIterator __first
, _InputIterator __last
,
175 const hasher
& __hf
= hasher(),
176 const key_equal
& __eql
= key_equal(),
177 const allocator_type
& __a
= allocator_type())
178 : _M_h(__first
, __last
, __n
, __hf
, __eql
, __a
)
181 /// Copy constructor.
182 unordered_set(const unordered_set
&) = default;
184 /// Move constructor.
185 unordered_set(unordered_set
&&) = default;
188 * @brief Creates an %unordered_set with no elements.
189 * @param __a An allocator object.
192 unordered_set(const allocator_type
& __a
)
197 * @brief Copy constructor with allocator argument.
198 * @param __uset Input %unordered_set to copy.
199 * @param __a An allocator object.
201 unordered_set(const unordered_set
& __uset
,
202 const allocator_type
& __a
)
203 : _M_h(__uset
._M_h
, __a
)
207 * @brief Move constructor with allocator argument.
208 * @param __uset Input %unordered_set to move.
209 * @param __a An allocator object.
211 unordered_set(unordered_set
&& __uset
,
212 const allocator_type
& __a
)
213 noexcept( noexcept(_Hashtable(std::move(__uset
._M_h
), __a
)) )
214 : _M_h(std::move(__uset
._M_h
), __a
)
218 * @brief Builds an %unordered_set from an initializer_list.
219 * @param __l An initializer_list.
220 * @param __n Minimal initial number of buckets.
221 * @param __hf A hash functor.
222 * @param __eql A key equality functor.
223 * @param __a An allocator object.
225 * Create an %unordered_set consisting of copies of the elements in the
226 * list. This is linear in N (where N is @a __l.size()).
228 unordered_set(initializer_list
<value_type
> __l
,
230 const hasher
& __hf
= hasher(),
231 const key_equal
& __eql
= key_equal(),
232 const allocator_type
& __a
= allocator_type())
233 : _M_h(__l
, __n
, __hf
, __eql
, __a
)
236 unordered_set(size_type __n
, const allocator_type
& __a
)
237 : unordered_set(__n
, hasher(), key_equal(), __a
)
240 unordered_set(size_type __n
, const hasher
& __hf
,
241 const allocator_type
& __a
)
242 : unordered_set(__n
, __hf
, key_equal(), __a
)
245 template<typename _InputIterator
>
246 unordered_set(_InputIterator __first
, _InputIterator __last
,
248 const allocator_type
& __a
)
249 : unordered_set(__first
, __last
, __n
, hasher(), key_equal(), __a
)
252 template<typename _InputIterator
>
253 unordered_set(_InputIterator __first
, _InputIterator __last
,
254 size_type __n
, const hasher
& __hf
,
255 const allocator_type
& __a
)
256 : unordered_set(__first
, __last
, __n
, __hf
, key_equal(), __a
)
259 unordered_set(initializer_list
<value_type
> __l
,
261 const allocator_type
& __a
)
262 : unordered_set(__l
, __n
, hasher(), key_equal(), __a
)
265 unordered_set(initializer_list
<value_type
> __l
,
266 size_type __n
, const hasher
& __hf
,
267 const allocator_type
& __a
)
268 : unordered_set(__l
, __n
, __hf
, key_equal(), __a
)
271 /// Copy assignment operator.
273 operator=(const unordered_set
&) = default;
275 /// Move assignment operator.
277 operator=(unordered_set
&&) = default;
280 * @brief %Unordered_set list assignment operator.
281 * @param __l An initializer_list.
283 * This function fills an %unordered_set with copies of the elements in
284 * the initializer list @a __l.
286 * Note that the assignment completely changes the %unordered_set and
287 * that the resulting %unordered_set's size is the same as the number
288 * of elements assigned.
291 operator=(initializer_list
<value_type
> __l
)
297 /// Returns the allocator object used by the %unordered_set.
299 get_allocator() const noexcept
300 { return _M_h
.get_allocator(); }
302 // size and capacity:
304 /// Returns true if the %unordered_set is empty.
305 _GLIBCXX_NODISCARD
bool
306 empty() const noexcept
307 { return _M_h
.empty(); }
309 /// Returns the size of the %unordered_set.
311 size() const noexcept
312 { return _M_h
.size(); }
314 /// Returns the maximum size of the %unordered_set.
316 max_size() const noexcept
317 { return _M_h
.max_size(); }
323 * Returns a read-only (constant) iterator that points to the first
324 * element in the %unordered_set.
328 { return _M_h
.begin(); }
331 begin() const noexcept
332 { return _M_h
.begin(); }
337 * Returns a read-only (constant) iterator that points one past the last
338 * element in the %unordered_set.
342 { return _M_h
.end(); }
346 { return _M_h
.end(); }
350 * Returns a read-only (constant) iterator that points to the first
351 * element in the %unordered_set.
354 cbegin() const noexcept
355 { return _M_h
.begin(); }
358 * Returns a read-only (constant) iterator that points one past the last
359 * element in the %unordered_set.
362 cend() const noexcept
363 { return _M_h
.end(); }
368 * @brief Attempts to build and insert an element into the
370 * @param __args Arguments used to generate an element.
371 * @return A pair, of which the first element is an iterator that points
372 * to the possibly inserted element, and the second is a bool
373 * that is true if the element was actually inserted.
375 * This function attempts to build and insert an element into the
376 * %unordered_set. An %unordered_set relies on unique keys and thus an
377 * element is only inserted if it is not already present in the
380 * Insertion requires amortized constant time.
382 template<typename
... _Args
>
383 std::pair
<iterator
, bool>
384 emplace(_Args
&&... __args
)
385 { return _M_h
.emplace(std::forward
<_Args
>(__args
)...); }
388 * @brief Attempts to insert an element into the %unordered_set.
389 * @param __pos An iterator that serves as a hint as to where the
390 * element should be inserted.
391 * @param __args Arguments used to generate the element to be
393 * @return An iterator that points to the element with key equivalent to
394 * the one generated from @a __args (may or may not be the
397 * This function is not concerned about whether the insertion took place,
398 * and thus does not return a boolean like the single-argument emplace()
399 * does. Note that the first parameter is only a hint and can
400 * potentially improve the performance of the insertion process. A bad
401 * hint would cause no gains in efficiency.
403 * For more on @a hinting, see:
404 * https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints
406 * Insertion requires amortized constant time.
408 template<typename
... _Args
>
410 emplace_hint(const_iterator __pos
, _Args
&&... __args
)
411 { return _M_h
.emplace_hint(__pos
, std::forward
<_Args
>(__args
)...); }
415 * @brief Attempts to insert an element into the %unordered_set.
416 * @param __x Element to be inserted.
417 * @return A pair, of which the first element is an iterator that points
418 * to the possibly inserted element, and the second is a bool
419 * that is true if the element was actually inserted.
421 * This function attempts to insert an element into the %unordered_set.
422 * An %unordered_set relies on unique keys and thus an element is only
423 * inserted if it is not already present in the %unordered_set.
425 * Insertion requires amortized constant time.
427 std::pair
<iterator
, bool>
428 insert(const value_type
& __x
)
429 { return _M_h
.insert(__x
); }
431 std::pair
<iterator
, bool>
432 insert(value_type
&& __x
)
433 { return _M_h
.insert(std::move(__x
)); }
438 * @brief Attempts to insert an element into the %unordered_set.
439 * @param __hint An iterator that serves as a hint as to where the
440 * element should be inserted.
441 * @param __x Element to be inserted.
442 * @return An iterator that points to the element with key of
443 * @a __x (may or may not be the element passed in).
445 * This function is not concerned about whether the insertion took place,
446 * and thus does not return a boolean like the single-argument insert()
447 * does. Note that the first parameter is only a hint and can
448 * potentially improve the performance of the insertion process. A bad
449 * hint would cause no gains in efficiency.
451 * For more on @a hinting, see:
452 * https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints
454 * Insertion requires amortized constant.
457 insert(const_iterator __hint
, const value_type
& __x
)
458 { return _M_h
.insert(__hint
, __x
); }
461 insert(const_iterator __hint
, value_type
&& __x
)
462 { return _M_h
.insert(__hint
, std::move(__x
)); }
466 * @brief A template function that attempts to insert a range of
468 * @param __first Iterator pointing to the start of the range to be
470 * @param __last Iterator pointing to the end of the range.
472 * Complexity similar to that of the range constructor.
474 template<typename _InputIterator
>
476 insert(_InputIterator __first
, _InputIterator __last
)
477 { _M_h
.insert(__first
, __last
); }
480 * @brief Attempts to insert a list of elements into the %unordered_set.
481 * @param __l A std::initializer_list<value_type> of elements
484 * Complexity similar to that of the range constructor.
487 insert(initializer_list
<value_type
> __l
)
488 { _M_h
.insert(__l
); }
490 #if __cplusplus > 201402L
493 extract(const_iterator __pos
)
495 __glibcxx_assert(__pos
!= end());
496 return _M_h
.extract(__pos
);
501 extract(const key_type
& __key
)
502 { return _M_h
.extract(__key
); }
504 /// Re-insert an extracted node.
506 insert(node_type
&& __nh
)
507 { return _M_h
._M_reinsert_node(std::move(__nh
)); }
509 /// Re-insert an extracted node.
511 insert(const_iterator
, node_type
&& __nh
)
512 { return _M_h
._M_reinsert_node(std::move(__nh
)).position
; }
517 * @brief Erases an element from an %unordered_set.
518 * @param __position An iterator pointing to the element to be erased.
519 * @return An iterator pointing to the element immediately following
520 * @a __position prior to the element being erased. If no such
521 * element exists, end() is returned.
523 * This function erases an element, pointed to by the given iterator,
524 * from an %unordered_set. Note that this function only erases the
525 * element, and that if the element is itself a pointer, the pointed-to
526 * memory is not touched in any way. Managing the pointer is the user's
530 erase(const_iterator __position
)
531 { return _M_h
.erase(__position
); }
535 erase(iterator __position
)
536 { return _M_h
.erase(__position
); }
540 * @brief Erases elements according to the provided key.
541 * @param __x Key of element to be erased.
542 * @return The number of elements erased.
544 * This function erases all the elements located by the given key from
545 * an %unordered_set. For an %unordered_set the result of this function
546 * can only be 0 (not present) or 1 (present).
547 * Note that this function only erases the element, and that if
548 * the element is itself a pointer, the pointed-to memory is not touched
549 * in any way. Managing the pointer is the user's responsibility.
552 erase(const key_type
& __x
)
553 { return _M_h
.erase(__x
); }
556 * @brief Erases a [__first,__last) range of elements from an
558 * @param __first Iterator pointing to the start of the range to be
560 * @param __last Iterator pointing to the end of the range to
562 * @return The iterator @a __last.
564 * This function erases a sequence of elements from an %unordered_set.
565 * Note that this function only erases the element, and that if
566 * the element is itself a pointer, the pointed-to memory is not touched
567 * in any way. Managing the pointer is the user's responsibility.
570 erase(const_iterator __first
, const_iterator __last
)
571 { return _M_h
.erase(__first
, __last
); }
574 * Erases all elements in an %unordered_set. Note that this function only
575 * erases the elements, and that if the elements themselves are pointers,
576 * the pointed-to memory is not touched in any way. Managing the pointer
577 * is the user's responsibility.
584 * @brief Swaps data with another %unordered_set.
585 * @param __x An %unordered_set of the same element and allocator
588 * This exchanges the elements between two sets in constant time.
589 * Note that the global std::swap() function is specialized such that
590 * std::swap(s1,s2) will feed to this function.
593 swap(unordered_set
& __x
)
594 noexcept( noexcept(_M_h
.swap(__x
._M_h
)) )
595 { _M_h
.swap(__x
._M_h
); }
597 #if __cplusplus > 201402L
598 template<typename
, typename
, typename
>
599 friend class std::_Hash_merge_helper
;
601 template<typename _H2
, typename _P2
>
603 merge(unordered_set
<_Value
, _H2
, _P2
, _Alloc
>& __source
)
605 using _Merge_helper
= _Hash_merge_helper
<unordered_set
, _H2
, _P2
>;
606 _M_h
._M_merge_unique(_Merge_helper::_S_get_table(__source
));
609 template<typename _H2
, typename _P2
>
611 merge(unordered_set
<_Value
, _H2
, _P2
, _Alloc
>&& __source
)
614 template<typename _H2
, typename _P2
>
616 merge(unordered_multiset
<_Value
, _H2
, _P2
, _Alloc
>& __source
)
618 using _Merge_helper
= _Hash_merge_helper
<unordered_set
, _H2
, _P2
>;
619 _M_h
._M_merge_unique(_Merge_helper::_S_get_table(__source
));
622 template<typename _H2
, typename _P2
>
624 merge(unordered_multiset
<_Value
, _H2
, _P2
, _Alloc
>&& __source
)
630 /// Returns the hash functor object with which the %unordered_set was
633 hash_function() const
634 { return _M_h
.hash_function(); }
636 /// Returns the key comparison object with which the %unordered_set was
640 { return _M_h
.key_eq(); }
646 * @brief Tries to locate an element in an %unordered_set.
647 * @param __x Element to be located.
648 * @return Iterator pointing to sought-after element, or end() if not
651 * This function takes a key and tries to locate the element with which
652 * the key matches. If successful the function returns an iterator
653 * pointing to the sought after element. If unsuccessful it returns the
654 * past-the-end ( @c end() ) iterator.
657 find(const key_type
& __x
)
658 { return _M_h
.find(__x
); }
660 #if __cplusplus > 201703L
661 template<typename _Kt
>
664 -> decltype(_M_h
._M_find_tr(__k
))
665 { return _M_h
._M_find_tr(__k
); }
669 find(const key_type
& __x
) const
670 { return _M_h
.find(__x
); }
672 #if __cplusplus > 201703L
673 template<typename _Kt
>
675 find(const _Kt
& __k
) const
676 -> decltype(_M_h
._M_find_tr(__k
))
677 { return _M_h
._M_find_tr(__k
); }
683 * @brief Finds the number of elements.
684 * @param __x Element to located.
685 * @return Number of elements with specified key.
687 * This function only makes sense for unordered_multisets; for
688 * unordered_set the result will either be 0 (not present) or 1
692 count(const key_type
& __x
) const
693 { return _M_h
.count(__x
); }
695 #if __cplusplus > 201703L
696 template<typename _Kt
>
698 count(const _Kt
& __k
) const
699 -> decltype(_M_h
._M_count_tr(__k
))
700 { return _M_h
._M_count_tr(__k
); }
704 #if __cplusplus > 201703L
707 * @brief Finds whether an element with the given key exists.
708 * @param __x Key of elements to be located.
709 * @return True if there is any element with the specified key.
712 contains(const key_type
& __x
) const
713 { return _M_h
.find(__x
) != _M_h
.end(); }
715 template<typename _Kt
>
717 contains(const _Kt
& __k
) const
718 -> decltype(_M_h
._M_find_tr(__k
), void(), true)
719 { return _M_h
._M_find_tr(__k
) != _M_h
.end(); }
725 * @brief Finds a subsequence matching given key.
726 * @param __x Key to be located.
727 * @return Pair of iterators that possibly points to the subsequence
728 * matching given key.
730 * This function probably only makes sense for multisets.
732 std::pair
<iterator
, iterator
>
733 equal_range(const key_type
& __x
)
734 { return _M_h
.equal_range(__x
); }
736 #if __cplusplus > 201703L
737 template<typename _Kt
>
739 equal_range(const _Kt
& __k
)
740 -> decltype(_M_h
._M_equal_range_tr(__k
))
741 { return _M_h
._M_equal_range_tr(__k
); }
744 std::pair
<const_iterator
, const_iterator
>
745 equal_range(const key_type
& __x
) const
746 { return _M_h
.equal_range(__x
); }
748 #if __cplusplus > 201703L
749 template<typename _Kt
>
751 equal_range(const _Kt
& __k
) const
752 -> decltype(_M_h
._M_equal_range_tr(__k
))
753 { return _M_h
._M_equal_range_tr(__k
); }
759 /// Returns the number of buckets of the %unordered_set.
761 bucket_count() const noexcept
762 { return _M_h
.bucket_count(); }
764 /// Returns the maximum number of buckets of the %unordered_set.
766 max_bucket_count() const noexcept
767 { return _M_h
.max_bucket_count(); }
770 * @brief Returns the number of elements in a given bucket.
771 * @param __n A bucket index.
772 * @return The number of elements in the bucket.
775 bucket_size(size_type __n
) const
776 { return _M_h
.bucket_size(__n
); }
779 * @brief Returns the bucket index of a given element.
780 * @param __key A key instance.
781 * @return The key bucket index.
784 bucket(const key_type
& __key
) const
785 { return _M_h
.bucket(__key
); }
789 * @brief Returns a read-only (constant) iterator pointing to the first
791 * @param __n The bucket index.
792 * @return A read-only local iterator.
796 { return _M_h
.begin(__n
); }
799 begin(size_type __n
) const
800 { return _M_h
.begin(__n
); }
803 cbegin(size_type __n
) const
804 { return _M_h
.cbegin(__n
); }
809 * @brief Returns a read-only (constant) iterator pointing to one past
810 * the last bucket elements.
811 * @param __n The bucket index.
812 * @return A read-only local iterator.
816 { return _M_h
.end(__n
); }
819 end(size_type __n
) const
820 { return _M_h
.end(__n
); }
823 cend(size_type __n
) const
824 { return _M_h
.cend(__n
); }
829 /// Returns the average number of elements per bucket.
831 load_factor() const noexcept
832 { return _M_h
.load_factor(); }
834 /// Returns a positive number that the %unordered_set tries to keep the
835 /// load factor less than or equal to.
837 max_load_factor() const noexcept
838 { return _M_h
.max_load_factor(); }
841 * @brief Change the %unordered_set maximum load factor.
842 * @param __z The new maximum load factor.
845 max_load_factor(float __z
)
846 { _M_h
.max_load_factor(__z
); }
849 * @brief May rehash the %unordered_set.
850 * @param __n The new number of buckets.
852 * Rehash will occur only if the new number of buckets respect the
853 * %unordered_set maximum load factor.
856 rehash(size_type __n
)
857 { _M_h
.rehash(__n
); }
860 * @brief Prepare the %unordered_set for a specified number of
862 * @param __n Number of elements required.
864 * Same as rehash(ceil(n / max_load_factor())).
867 reserve(size_type __n
)
868 { _M_h
.reserve(__n
); }
870 template<typename _Value1
, typename _Hash1
, typename _Pred1
,
873 operator==(const unordered_set
<_Value1
, _Hash1
, _Pred1
, _Alloc1
>&,
874 const unordered_set
<_Value1
, _Hash1
, _Pred1
, _Alloc1
>&);
877 #if __cpp_deduction_guides >= 201606
879 template<typename _InputIterator
,
881 hash
<typename iterator_traits
<_InputIterator
>::value_type
>,
883 equal_to
<typename iterator_traits
<_InputIterator
>::value_type
>,
884 typename _Allocator
=
885 allocator
<typename iterator_traits
<_InputIterator
>::value_type
>,
886 typename
= _RequireInputIter
<_InputIterator
>,
887 typename
= _RequireNotAllocatorOrIntegral
<_Hash
>,
888 typename
= _RequireNotAllocator
<_Pred
>,
889 typename
= _RequireAllocator
<_Allocator
>>
890 unordered_set(_InputIterator
, _InputIterator
,
891 unordered_set
<int>::size_type
= {},
892 _Hash
= _Hash(), _Pred
= _Pred(), _Allocator
= _Allocator())
893 -> unordered_set
<typename iterator_traits
<_InputIterator
>::value_type
,
894 _Hash
, _Pred
, _Allocator
>;
896 template<typename _Tp
, typename _Hash
= hash
<_Tp
>,
897 typename _Pred
= equal_to
<_Tp
>,
898 typename _Allocator
= allocator
<_Tp
>,
899 typename
= _RequireNotAllocatorOrIntegral
<_Hash
>,
900 typename
= _RequireNotAllocator
<_Pred
>,
901 typename
= _RequireAllocator
<_Allocator
>>
902 unordered_set(initializer_list
<_Tp
>,
903 unordered_set
<int>::size_type
= {},
904 _Hash
= _Hash(), _Pred
= _Pred(), _Allocator
= _Allocator())
905 -> unordered_set
<_Tp
, _Hash
, _Pred
, _Allocator
>;
907 template<typename _InputIterator
, typename _Allocator
,
908 typename
= _RequireInputIter
<_InputIterator
>,
909 typename
= _RequireAllocator
<_Allocator
>>
910 unordered_set(_InputIterator
, _InputIterator
,
911 unordered_set
<int>::size_type
, _Allocator
)
912 -> unordered_set
<typename iterator_traits
<_InputIterator
>::value_type
,
914 typename iterator_traits
<_InputIterator
>::value_type
>,
916 typename iterator_traits
<_InputIterator
>::value_type
>,
919 template<typename _InputIterator
, typename _Hash
, typename _Allocator
,
920 typename
= _RequireInputIter
<_InputIterator
>,
921 typename
= _RequireNotAllocatorOrIntegral
<_Hash
>,
922 typename
= _RequireAllocator
<_Allocator
>>
923 unordered_set(_InputIterator
, _InputIterator
,
924 unordered_set
<int>::size_type
,
926 -> unordered_set
<typename iterator_traits
<_InputIterator
>::value_type
,
929 typename iterator_traits
<_InputIterator
>::value_type
>,
932 template<typename _Tp
, typename _Allocator
,
933 typename
= _RequireAllocator
<_Allocator
>>
934 unordered_set(initializer_list
<_Tp
>,
935 unordered_set
<int>::size_type
, _Allocator
)
936 -> unordered_set
<_Tp
, hash
<_Tp
>, equal_to
<_Tp
>, _Allocator
>;
938 template<typename _Tp
, typename _Hash
, typename _Allocator
,
939 typename
= _RequireNotAllocatorOrIntegral
<_Hash
>,
940 typename
= _RequireAllocator
<_Allocator
>>
941 unordered_set(initializer_list
<_Tp
>,
942 unordered_set
<int>::size_type
, _Hash
, _Allocator
)
943 -> unordered_set
<_Tp
, _Hash
, equal_to
<_Tp
>, _Allocator
>;
948 * @brief A standard container composed of equivalent keys
949 * (possibly containing multiple of each key value) in which the
950 * elements' keys are the elements themselves.
952 * @ingroup unordered_associative_containers
953 * @headerfile unordered_set
956 * @tparam _Value Type of key objects.
957 * @tparam _Hash Hashing function object type, defaults to hash<_Value>.
958 * @tparam _Pred Predicate function object type, defaults
959 * to equal_to<_Value>.
960 * @tparam _Alloc Allocator type, defaults to allocator<_Key>.
962 * Meets the requirements of a <a href="tables.html#65">container</a>, and
963 * <a href="tables.html#xx">unordered associative container</a>
965 * Base is _Hashtable, dispatched at compile time via template
966 * alias __umset_hashtable.
968 template<typename _Value
,
969 typename _Hash
= hash
<_Value
>,
970 typename _Pred
= equal_to
<_Value
>,
971 typename _Alloc
= allocator
<_Value
>>
972 class unordered_multiset
974 typedef __umset_hashtable
<_Value
, _Hash
, _Pred
, _Alloc
> _Hashtable
;
981 typedef typename
_Hashtable::key_type key_type
;
982 typedef typename
_Hashtable::value_type value_type
;
983 typedef typename
_Hashtable::hasher hasher
;
984 typedef typename
_Hashtable::key_equal key_equal
;
985 typedef typename
_Hashtable::allocator_type allocator_type
;
989 /// Iterator-related typedefs.
990 typedef typename
_Hashtable::pointer pointer
;
991 typedef typename
_Hashtable::const_pointer const_pointer
;
992 typedef typename
_Hashtable::reference reference
;
993 typedef typename
_Hashtable::const_reference const_reference
;
994 typedef typename
_Hashtable::iterator iterator
;
995 typedef typename
_Hashtable::const_iterator const_iterator
;
996 typedef typename
_Hashtable::local_iterator local_iterator
;
997 typedef typename
_Hashtable::const_local_iterator const_local_iterator
;
998 typedef typename
_Hashtable::size_type size_type
;
999 typedef typename
_Hashtable::difference_type difference_type
;
1002 #if __cplusplus > 201402L
1003 using node_type
= typename
_Hashtable::node_type
;
1006 // construct/destroy/copy
1008 /// Default constructor.
1009 unordered_multiset() = default;
1012 * @brief Default constructor creates no elements.
1013 * @param __n Minimal initial number of buckets.
1014 * @param __hf A hash functor.
1015 * @param __eql A key equality functor.
1016 * @param __a An allocator object.
1019 unordered_multiset(size_type __n
,
1020 const hasher
& __hf
= hasher(),
1021 const key_equal
& __eql
= key_equal(),
1022 const allocator_type
& __a
= allocator_type())
1023 : _M_h(__n
, __hf
, __eql
, __a
)
1027 * @brief Builds an %unordered_multiset from a range.
1028 * @param __first An input iterator.
1029 * @param __last An input iterator.
1030 * @param __n Minimal initial number of buckets.
1031 * @param __hf A hash functor.
1032 * @param __eql A key equality functor.
1033 * @param __a An allocator object.
1035 * Create an %unordered_multiset consisting of copies of the elements
1036 * from [__first,__last). This is linear in N (where N is
1037 * distance(__first,__last)).
1039 template<typename _InputIterator
>
1040 unordered_multiset(_InputIterator __first
, _InputIterator __last
,
1042 const hasher
& __hf
= hasher(),
1043 const key_equal
& __eql
= key_equal(),
1044 const allocator_type
& __a
= allocator_type())
1045 : _M_h(__first
, __last
, __n
, __hf
, __eql
, __a
)
1048 /// Copy constructor.
1049 unordered_multiset(const unordered_multiset
&) = default;
1051 /// Move constructor.
1052 unordered_multiset(unordered_multiset
&&) = default;
1055 * @brief Builds an %unordered_multiset from an initializer_list.
1056 * @param __l An initializer_list.
1057 * @param __n Minimal initial number of buckets.
1058 * @param __hf A hash functor.
1059 * @param __eql A key equality functor.
1060 * @param __a An allocator object.
1062 * Create an %unordered_multiset consisting of copies of the elements in
1063 * the list. This is linear in N (where N is @a __l.size()).
1065 unordered_multiset(initializer_list
<value_type
> __l
,
1067 const hasher
& __hf
= hasher(),
1068 const key_equal
& __eql
= key_equal(),
1069 const allocator_type
& __a
= allocator_type())
1070 : _M_h(__l
, __n
, __hf
, __eql
, __a
)
1073 /// Copy assignment operator.
1075 operator=(const unordered_multiset
&) = default;
1077 /// Move assignment operator.
1079 operator=(unordered_multiset
&&) = default;
1082 * @brief Creates an %unordered_multiset with no elements.
1083 * @param __a An allocator object.
1086 unordered_multiset(const allocator_type
& __a
)
1091 * @brief Copy constructor with allocator argument.
1092 * @param __uset Input %unordered_multiset to copy.
1093 * @param __a An allocator object.
1095 unordered_multiset(const unordered_multiset
& __umset
,
1096 const allocator_type
& __a
)
1097 : _M_h(__umset
._M_h
, __a
)
1101 * @brief Move constructor with allocator argument.
1102 * @param __umset Input %unordered_multiset to move.
1103 * @param __a An allocator object.
1105 unordered_multiset(unordered_multiset
&& __umset
,
1106 const allocator_type
& __a
)
1107 noexcept( noexcept(_Hashtable(std::move(__umset
._M_h
), __a
)) )
1108 : _M_h(std::move(__umset
._M_h
), __a
)
1111 unordered_multiset(size_type __n
, const allocator_type
& __a
)
1112 : unordered_multiset(__n
, hasher(), key_equal(), __a
)
1115 unordered_multiset(size_type __n
, const hasher
& __hf
,
1116 const allocator_type
& __a
)
1117 : unordered_multiset(__n
, __hf
, key_equal(), __a
)
1120 template<typename _InputIterator
>
1121 unordered_multiset(_InputIterator __first
, _InputIterator __last
,
1123 const allocator_type
& __a
)
1124 : unordered_multiset(__first
, __last
, __n
, hasher(), key_equal(), __a
)
1127 template<typename _InputIterator
>
1128 unordered_multiset(_InputIterator __first
, _InputIterator __last
,
1129 size_type __n
, const hasher
& __hf
,
1130 const allocator_type
& __a
)
1131 : unordered_multiset(__first
, __last
, __n
, __hf
, key_equal(), __a
)
1134 unordered_multiset(initializer_list
<value_type
> __l
,
1136 const allocator_type
& __a
)
1137 : unordered_multiset(__l
, __n
, hasher(), key_equal(), __a
)
1140 unordered_multiset(initializer_list
<value_type
> __l
,
1141 size_type __n
, const hasher
& __hf
,
1142 const allocator_type
& __a
)
1143 : unordered_multiset(__l
, __n
, __hf
, key_equal(), __a
)
1147 * @brief %Unordered_multiset list assignment operator.
1148 * @param __l An initializer_list.
1150 * This function fills an %unordered_multiset with copies of the elements
1151 * in the initializer list @a __l.
1153 * Note that the assignment completely changes the %unordered_multiset
1154 * and that the resulting %unordered_multiset's size is the same as the
1155 * number of elements assigned.
1158 operator=(initializer_list
<value_type
> __l
)
1164 /// Returns the allocator object used by the %unordered_multiset.
1166 get_allocator() const noexcept
1167 { return _M_h
.get_allocator(); }
1169 // size and capacity:
1171 /// Returns true if the %unordered_multiset is empty.
1172 _GLIBCXX_NODISCARD
bool
1173 empty() const noexcept
1174 { return _M_h
.empty(); }
1176 /// Returns the size of the %unordered_multiset.
1178 size() const noexcept
1179 { return _M_h
.size(); }
1181 /// Returns the maximum size of the %unordered_multiset.
1183 max_size() const noexcept
1184 { return _M_h
.max_size(); }
1190 * Returns a read-only (constant) iterator that points to the first
1191 * element in the %unordered_multiset.
1195 { return _M_h
.begin(); }
1198 begin() const noexcept
1199 { return _M_h
.begin(); }
1204 * Returns a read-only (constant) iterator that points one past the last
1205 * element in the %unordered_multiset.
1209 { return _M_h
.end(); }
1212 end() const noexcept
1213 { return _M_h
.end(); }
1217 * Returns a read-only (constant) iterator that points to the first
1218 * element in the %unordered_multiset.
1221 cbegin() const noexcept
1222 { return _M_h
.begin(); }
1225 * Returns a read-only (constant) iterator that points one past the last
1226 * element in the %unordered_multiset.
1229 cend() const noexcept
1230 { return _M_h
.end(); }
1235 * @brief Builds and insert an element into the %unordered_multiset.
1236 * @param __args Arguments used to generate an element.
1237 * @return An iterator that points to the inserted element.
1239 * Insertion requires amortized constant time.
1241 template<typename
... _Args
>
1243 emplace(_Args
&&... __args
)
1244 { return _M_h
.emplace(std::forward
<_Args
>(__args
)...); }
1247 * @brief Inserts an element into the %unordered_multiset.
1248 * @param __pos An iterator that serves as a hint as to where the
1249 * element should be inserted.
1250 * @param __args Arguments used to generate the element to be
1252 * @return An iterator that points to the inserted element.
1254 * Note that the first parameter is only a hint and can potentially
1255 * improve the performance of the insertion process. A bad hint would
1256 * cause no gains in efficiency.
1258 * For more on @a hinting, see:
1259 * https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints
1261 * Insertion requires amortized constant time.
1263 template<typename
... _Args
>
1265 emplace_hint(const_iterator __pos
, _Args
&&... __args
)
1266 { return _M_h
.emplace_hint(__pos
, std::forward
<_Args
>(__args
)...); }
1270 * @brief Inserts an element into the %unordered_multiset.
1271 * @param __x Element to be inserted.
1272 * @return An iterator that points to the inserted element.
1274 * Insertion requires amortized constant time.
1277 insert(const value_type
& __x
)
1278 { return _M_h
.insert(__x
); }
1281 insert(value_type
&& __x
)
1282 { return _M_h
.insert(std::move(__x
)); }
1287 * @brief Inserts an element into the %unordered_multiset.
1288 * @param __hint An iterator that serves as a hint as to where the
1289 * element should be inserted.
1290 * @param __x Element to be inserted.
1291 * @return An iterator that points to the inserted element.
1293 * Note that the first parameter is only a hint and can potentially
1294 * improve the performance of the insertion process. A bad hint would
1295 * cause no gains in efficiency.
1297 * For more on @a hinting, see:
1298 * https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints
1300 * Insertion requires amortized constant.
1303 insert(const_iterator __hint
, const value_type
& __x
)
1304 { return _M_h
.insert(__hint
, __x
); }
1307 insert(const_iterator __hint
, value_type
&& __x
)
1308 { return _M_h
.insert(__hint
, std::move(__x
)); }
1312 * @brief A template function that inserts a range of elements.
1313 * @param __first Iterator pointing to the start of the range to be
1315 * @param __last Iterator pointing to the end of the range.
1317 * Complexity similar to that of the range constructor.
1319 template<typename _InputIterator
>
1321 insert(_InputIterator __first
, _InputIterator __last
)
1322 { _M_h
.insert(__first
, __last
); }
1325 * @brief Inserts a list of elements into the %unordered_multiset.
1326 * @param __l A std::initializer_list<value_type> of elements to be
1329 * Complexity similar to that of the range constructor.
1332 insert(initializer_list
<value_type
> __l
)
1333 { _M_h
.insert(__l
); }
1335 #if __cplusplus > 201402L
1338 extract(const_iterator __pos
)
1340 __glibcxx_assert(__pos
!= end());
1341 return _M_h
.extract(__pos
);
1346 extract(const key_type
& __key
)
1347 { return _M_h
.extract(__key
); }
1349 /// Re-insert an extracted node.
1351 insert(node_type
&& __nh
)
1352 { return _M_h
._M_reinsert_node_multi(cend(), std::move(__nh
)); }
1354 /// Re-insert an extracted node.
1356 insert(const_iterator __hint
, node_type
&& __nh
)
1357 { return _M_h
._M_reinsert_node_multi(__hint
, std::move(__nh
)); }
1362 * @brief Erases an element from an %unordered_multiset.
1363 * @param __position An iterator pointing to the element to be erased.
1364 * @return An iterator pointing to the element immediately following
1365 * @a __position prior to the element being erased. If no such
1366 * element exists, end() is returned.
1368 * This function erases an element, pointed to by the given iterator,
1369 * from an %unordered_multiset.
1371 * Note that this function only erases the element, and that if the
1372 * element is itself a pointer, the pointed-to memory is not touched in
1373 * any way. Managing the pointer is the user's responsibility.
1376 erase(const_iterator __position
)
1377 { return _M_h
.erase(__position
); }
1381 erase(iterator __position
)
1382 { return _M_h
.erase(__position
); }
1387 * @brief Erases elements according to the provided key.
1388 * @param __x Key of element to be erased.
1389 * @return The number of elements erased.
1391 * This function erases all the elements located by the given key from
1392 * an %unordered_multiset.
1394 * Note that this function only erases the element, and that if the
1395 * element is itself a pointer, the pointed-to memory is not touched in
1396 * any way. Managing the pointer is the user's responsibility.
1399 erase(const key_type
& __x
)
1400 { return _M_h
.erase(__x
); }
1403 * @brief Erases a [__first,__last) range of elements from an
1404 * %unordered_multiset.
1405 * @param __first Iterator pointing to the start of the range to be
1407 * @param __last Iterator pointing to the end of the range to
1409 * @return The iterator @a __last.
1411 * This function erases a sequence of elements from an
1412 * %unordered_multiset.
1414 * Note that this function only erases the element, and that if
1415 * the element is itself a pointer, the pointed-to memory is not touched
1416 * in any way. Managing the pointer is the user's responsibility.
1419 erase(const_iterator __first
, const_iterator __last
)
1420 { return _M_h
.erase(__first
, __last
); }
1423 * Erases all elements in an %unordered_multiset.
1425 * Note that this function only erases the elements, and that if the
1426 * elements themselves are pointers, the pointed-to memory is not touched
1427 * in any way. Managing the pointer is the user's responsibility.
1434 * @brief Swaps data with another %unordered_multiset.
1435 * @param __x An %unordered_multiset of the same element and allocator
1438 * This exchanges the elements between two sets in constant time.
1439 * Note that the global std::swap() function is specialized such that
1440 * std::swap(s1,s2) will feed to this function.
1443 swap(unordered_multiset
& __x
)
1444 noexcept( noexcept(_M_h
.swap(__x
._M_h
)) )
1445 { _M_h
.swap(__x
._M_h
); }
1447 #if __cplusplus > 201402L
1448 template<typename
, typename
, typename
>
1449 friend class std::_Hash_merge_helper
;
1451 template<typename _H2
, typename _P2
>
1453 merge(unordered_multiset
<_Value
, _H2
, _P2
, _Alloc
>& __source
)
1456 = _Hash_merge_helper
<unordered_multiset
, _H2
, _P2
>;
1457 _M_h
._M_merge_multi(_Merge_helper::_S_get_table(__source
));
1460 template<typename _H2
, typename _P2
>
1462 merge(unordered_multiset
<_Value
, _H2
, _P2
, _Alloc
>&& __source
)
1463 { merge(__source
); }
1465 template<typename _H2
, typename _P2
>
1467 merge(unordered_set
<_Value
, _H2
, _P2
, _Alloc
>& __source
)
1470 = _Hash_merge_helper
<unordered_multiset
, _H2
, _P2
>;
1471 _M_h
._M_merge_multi(_Merge_helper::_S_get_table(__source
));
1474 template<typename _H2
, typename _P2
>
1476 merge(unordered_set
<_Value
, _H2
, _P2
, _Alloc
>&& __source
)
1477 { merge(__source
); }
1482 /// Returns the hash functor object with which the %unordered_multiset
1483 /// was constructed.
1485 hash_function() const
1486 { return _M_h
.hash_function(); }
1488 /// Returns the key comparison object with which the %unordered_multiset
1489 /// was constructed.
1492 { return _M_h
.key_eq(); }
1498 * @brief Tries to locate an element in an %unordered_multiset.
1499 * @param __x Element to be located.
1500 * @return Iterator pointing to sought-after element, or end() if not
1503 * This function takes a key and tries to locate the element with which
1504 * the key matches. If successful the function returns an iterator
1505 * pointing to the sought after element. If unsuccessful it returns the
1506 * past-the-end ( @c end() ) iterator.
1509 find(const key_type
& __x
)
1510 { return _M_h
.find(__x
); }
1512 #if __cplusplus > 201703L
1513 template<typename _Kt
>
1515 find(const _Kt
& __x
)
1516 -> decltype(_M_h
._M_find_tr(__x
))
1517 { return _M_h
._M_find_tr(__x
); }
1521 find(const key_type
& __x
) const
1522 { return _M_h
.find(__x
); }
1524 #if __cplusplus > 201703L
1525 template<typename _Kt
>
1527 find(const _Kt
& __x
) const
1528 -> decltype(_M_h
._M_find_tr(__x
))
1529 { return _M_h
._M_find_tr(__x
); }
1535 * @brief Finds the number of elements.
1536 * @param __x Element to located.
1537 * @return Number of elements with specified key.
1540 count(const key_type
& __x
) const
1541 { return _M_h
.count(__x
); }
1543 #if __cplusplus > 201703L
1544 template<typename _Kt
>
1546 count(const _Kt
& __x
) const -> decltype(_M_h
._M_count_tr(__x
))
1547 { return _M_h
._M_count_tr(__x
); }
1551 #if __cplusplus > 201703L
1554 * @brief Finds whether an element with the given key exists.
1555 * @param __x Key of elements to be located.
1556 * @return True if there is any element with the specified key.
1559 contains(const key_type
& __x
) const
1560 { return _M_h
.find(__x
) != _M_h
.end(); }
1562 template<typename _Kt
>
1564 contains(const _Kt
& __x
) const
1565 -> decltype(_M_h
._M_find_tr(__x
), void(), true)
1566 { return _M_h
._M_find_tr(__x
) != _M_h
.end(); }
1572 * @brief Finds a subsequence matching given key.
1573 * @param __x Key to be located.
1574 * @return Pair of iterators that possibly points to the subsequence
1575 * matching given key.
1577 std::pair
<iterator
, iterator
>
1578 equal_range(const key_type
& __x
)
1579 { return _M_h
.equal_range(__x
); }
1581 #if __cplusplus > 201703L
1582 template<typename _Kt
>
1584 equal_range(const _Kt
& __x
)
1585 -> decltype(_M_h
._M_equal_range_tr(__x
))
1586 { return _M_h
._M_equal_range_tr(__x
); }
1589 std::pair
<const_iterator
, const_iterator
>
1590 equal_range(const key_type
& __x
) const
1591 { return _M_h
.equal_range(__x
); }
1593 #if __cplusplus > 201703L
1594 template<typename _Kt
>
1596 equal_range(const _Kt
& __x
) const
1597 -> decltype(_M_h
._M_equal_range_tr(__x
))
1598 { return _M_h
._M_equal_range_tr(__x
); }
1602 // bucket interface.
1604 /// Returns the number of buckets of the %unordered_multiset.
1606 bucket_count() const noexcept
1607 { return _M_h
.bucket_count(); }
1609 /// Returns the maximum number of buckets of the %unordered_multiset.
1611 max_bucket_count() const noexcept
1612 { return _M_h
.max_bucket_count(); }
1615 * @brief Returns the number of elements in a given bucket.
1616 * @param __n A bucket index.
1617 * @return The number of elements in the bucket.
1620 bucket_size(size_type __n
) const
1621 { return _M_h
.bucket_size(__n
); }
1624 * @brief Returns the bucket index of a given element.
1625 * @param __key A key instance.
1626 * @return The key bucket index.
1629 bucket(const key_type
& __key
) const
1630 { return _M_h
.bucket(__key
); }
1634 * @brief Returns a read-only (constant) iterator pointing to the first
1636 * @param __n The bucket index.
1637 * @return A read-only local iterator.
1640 begin(size_type __n
)
1641 { return _M_h
.begin(__n
); }
1643 const_local_iterator
1644 begin(size_type __n
) const
1645 { return _M_h
.begin(__n
); }
1647 const_local_iterator
1648 cbegin(size_type __n
) const
1649 { return _M_h
.cbegin(__n
); }
1654 * @brief Returns a read-only (constant) iterator pointing to one past
1655 * the last bucket elements.
1656 * @param __n The bucket index.
1657 * @return A read-only local iterator.
1661 { return _M_h
.end(__n
); }
1663 const_local_iterator
1664 end(size_type __n
) const
1665 { return _M_h
.end(__n
); }
1667 const_local_iterator
1668 cend(size_type __n
) const
1669 { return _M_h
.cend(__n
); }
1674 /// Returns the average number of elements per bucket.
1676 load_factor() const noexcept
1677 { return _M_h
.load_factor(); }
1679 /// Returns a positive number that the %unordered_multiset tries to keep the
1680 /// load factor less than or equal to.
1682 max_load_factor() const noexcept
1683 { return _M_h
.max_load_factor(); }
1686 * @brief Change the %unordered_multiset maximum load factor.
1687 * @param __z The new maximum load factor.
1690 max_load_factor(float __z
)
1691 { _M_h
.max_load_factor(__z
); }
1694 * @brief May rehash the %unordered_multiset.
1695 * @param __n The new number of buckets.
1697 * Rehash will occur only if the new number of buckets respect the
1698 * %unordered_multiset maximum load factor.
1701 rehash(size_type __n
)
1702 { _M_h
.rehash(__n
); }
1705 * @brief Prepare the %unordered_multiset for a specified number of
1707 * @param __n Number of elements required.
1709 * Same as rehash(ceil(n / max_load_factor())).
1712 reserve(size_type __n
)
1713 { _M_h
.reserve(__n
); }
1715 template<typename _Value1
, typename _Hash1
, typename _Pred1
,
1718 operator==(const unordered_multiset
<_Value1
, _Hash1
, _Pred1
, _Alloc1
>&,
1719 const unordered_multiset
<_Value1
, _Hash1
, _Pred1
, _Alloc1
>&);
1723 #if __cpp_deduction_guides >= 201606
1725 template<typename _InputIterator
,
1727 hash
<typename iterator_traits
<_InputIterator
>::value_type
>,
1729 equal_to
<typename iterator_traits
<_InputIterator
>::value_type
>,
1730 typename _Allocator
=
1731 allocator
<typename iterator_traits
<_InputIterator
>::value_type
>,
1732 typename
= _RequireInputIter
<_InputIterator
>,
1733 typename
= _RequireNotAllocatorOrIntegral
<_Hash
>,
1734 typename
= _RequireNotAllocator
<_Pred
>,
1735 typename
= _RequireAllocator
<_Allocator
>>
1736 unordered_multiset(_InputIterator
, _InputIterator
,
1737 unordered_multiset
<int>::size_type
= {},
1738 _Hash
= _Hash(), _Pred
= _Pred(),
1739 _Allocator
= _Allocator())
1740 -> unordered_multiset
<typename iterator_traits
<_InputIterator
>::value_type
,
1741 _Hash
, _Pred
, _Allocator
>;
1743 template<typename _Tp
, typename _Hash
= hash
<_Tp
>,
1744 typename _Pred
= equal_to
<_Tp
>,
1745 typename _Allocator
= allocator
<_Tp
>,
1746 typename
= _RequireNotAllocatorOrIntegral
<_Hash
>,
1747 typename
= _RequireNotAllocator
<_Pred
>,
1748 typename
= _RequireAllocator
<_Allocator
>>
1749 unordered_multiset(initializer_list
<_Tp
>,
1750 unordered_multiset
<int>::size_type
= {},
1751 _Hash
= _Hash(), _Pred
= _Pred(),
1752 _Allocator
= _Allocator())
1753 -> unordered_multiset
<_Tp
, _Hash
, _Pred
, _Allocator
>;
1755 template<typename _InputIterator
, typename _Allocator
,
1756 typename
= _RequireInputIter
<_InputIterator
>,
1757 typename
= _RequireAllocator
<_Allocator
>>
1758 unordered_multiset(_InputIterator
, _InputIterator
,
1759 unordered_multiset
<int>::size_type
, _Allocator
)
1760 -> unordered_multiset
<typename iterator_traits
<_InputIterator
>::value_type
,
1762 iterator_traits
<_InputIterator
>::value_type
>,
1764 iterator_traits
<_InputIterator
>::value_type
>,
1767 template<typename _InputIterator
, typename _Hash
, typename _Allocator
,
1768 typename
= _RequireInputIter
<_InputIterator
>,
1769 typename
= _RequireNotAllocatorOrIntegral
<_Hash
>,
1770 typename
= _RequireAllocator
<_Allocator
>>
1771 unordered_multiset(_InputIterator
, _InputIterator
,
1772 unordered_multiset
<int>::size_type
,
1774 -> unordered_multiset
<typename
1775 iterator_traits
<_InputIterator
>::value_type
,
1779 iterator_traits
<_InputIterator
>::value_type
>,
1782 template<typename _Tp
, typename _Allocator
,
1783 typename
= _RequireAllocator
<_Allocator
>>
1784 unordered_multiset(initializer_list
<_Tp
>,
1785 unordered_multiset
<int>::size_type
, _Allocator
)
1786 -> unordered_multiset
<_Tp
, hash
<_Tp
>, equal_to
<_Tp
>, _Allocator
>;
1788 template<typename _Tp
, typename _Hash
, typename _Allocator
,
1789 typename
= _RequireNotAllocatorOrIntegral
<_Hash
>,
1790 typename
= _RequireAllocator
<_Allocator
>>
1791 unordered_multiset(initializer_list
<_Tp
>,
1792 unordered_multiset
<int>::size_type
, _Hash
, _Allocator
)
1793 -> unordered_multiset
<_Tp
, _Hash
, equal_to
<_Tp
>, _Allocator
>;
1797 template<class _Value
, class _Hash
, class _Pred
, class _Alloc
>
1799 swap(unordered_set
<_Value
, _Hash
, _Pred
, _Alloc
>& __x
,
1800 unordered_set
<_Value
, _Hash
, _Pred
, _Alloc
>& __y
)
1801 noexcept(noexcept(__x
.swap(__y
)))
1804 template<class _Value
, class _Hash
, class _Pred
, class _Alloc
>
1806 swap(unordered_multiset
<_Value
, _Hash
, _Pred
, _Alloc
>& __x
,
1807 unordered_multiset
<_Value
, _Hash
, _Pred
, _Alloc
>& __y
)
1808 noexcept(noexcept(__x
.swap(__y
)))
1811 template<class _Value
, class _Hash
, class _Pred
, class _Alloc
>
1813 operator==(const unordered_set
<_Value
, _Hash
, _Pred
, _Alloc
>& __x
,
1814 const unordered_set
<_Value
, _Hash
, _Pred
, _Alloc
>& __y
)
1815 { return __x
._M_h
._M_equal(__y
._M_h
); }
1817 #if __cpp_impl_three_way_comparison < 201907L
1818 template<class _Value
, class _Hash
, class _Pred
, class _Alloc
>
1820 operator!=(const unordered_set
<_Value
, _Hash
, _Pred
, _Alloc
>& __x
,
1821 const unordered_set
<_Value
, _Hash
, _Pred
, _Alloc
>& __y
)
1822 { return !(__x
== __y
); }
1825 template<class _Value
, class _Hash
, class _Pred
, class _Alloc
>
1827 operator==(const unordered_multiset
<_Value
, _Hash
, _Pred
, _Alloc
>& __x
,
1828 const unordered_multiset
<_Value
, _Hash
, _Pred
, _Alloc
>& __y
)
1829 { return __x
._M_h
._M_equal(__y
._M_h
); }
1831 #if __cpp_impl_three_way_comparison < 201907L
1832 template<class _Value
, class _Hash
, class _Pred
, class _Alloc
>
1834 operator!=(const unordered_multiset
<_Value
, _Hash
, _Pred
, _Alloc
>& __x
,
1835 const unordered_multiset
<_Value
, _Hash
, _Pred
, _Alloc
>& __y
)
1836 { return !(__x
== __y
); }
1839 _GLIBCXX_END_NAMESPACE_CONTAINER
1841 #if __cplusplus > 201402L
1842 // Allow std::unordered_set access to internals of compatible sets.
1843 template<typename _Val
, typename _Hash1
, typename _Eq1
, typename _Alloc
,
1844 typename _Hash2
, typename _Eq2
>
1845 struct _Hash_merge_helper
<
1846 _GLIBCXX_STD_C::unordered_set
<_Val
, _Hash1
, _Eq1
, _Alloc
>, _Hash2
, _Eq2
>
1849 template<typename
... _Tp
>
1850 using unordered_set
= _GLIBCXX_STD_C::unordered_set
<_Tp
...>;
1851 template<typename
... _Tp
>
1852 using unordered_multiset
= _GLIBCXX_STD_C::unordered_multiset
<_Tp
...>;
1854 friend unordered_set
<_Val
, _Hash1
, _Eq1
, _Alloc
>;
1857 _S_get_table(unordered_set
<_Val
, _Hash2
, _Eq2
, _Alloc
>& __set
)
1858 { return __set
._M_h
; }
1861 _S_get_table(unordered_multiset
<_Val
, _Hash2
, _Eq2
, _Alloc
>& __set
)
1862 { return __set
._M_h
; }
1865 // Allow std::unordered_multiset access to internals of compatible sets.
1866 template<typename _Val
, typename _Hash1
, typename _Eq1
, typename _Alloc
,
1867 typename _Hash2
, typename _Eq2
>
1868 struct _Hash_merge_helper
<
1869 _GLIBCXX_STD_C::unordered_multiset
<_Val
, _Hash1
, _Eq1
, _Alloc
>,
1873 template<typename
... _Tp
>
1874 using unordered_set
= _GLIBCXX_STD_C::unordered_set
<_Tp
...>;
1875 template<typename
... _Tp
>
1876 using unordered_multiset
= _GLIBCXX_STD_C::unordered_multiset
<_Tp
...>;
1878 friend unordered_multiset
<_Val
, _Hash1
, _Eq1
, _Alloc
>;
1881 _S_get_table(unordered_set
<_Val
, _Hash2
, _Eq2
, _Alloc
>& __set
)
1882 { return __set
._M_h
; }
1885 _S_get_table(unordered_multiset
<_Val
, _Hash2
, _Eq2
, _Alloc
>& __set
)
1886 { return __set
._M_h
; }
1890 _GLIBCXX_END_NAMESPACE_VERSION
1893 #endif /* _UNORDERED_SET_H */