1 // Multiset implementation -*- C++ -*-
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52 /** @file stl_multiset.h
53 * This is an internal header file, included by other library headers.
54 * You should not attempt to use it directly.
57 #ifndef _STL_MULTISET_H
58 #define _STL_MULTISET_H 1
60 #include <bits/concept_check.h>
61 #include <initializer_list>
63 _GLIBCXX_BEGIN_NESTED_NAMESPACE(std, _GLIBCXX_STD_D)
66 * @brief A standard container made up of elements, which can be retrieved
67 * in logarithmic time.
69 * @ingroup associative_containers
71 * Meets the requirements of a <a href="tables.html#65">container</a>, a
72 * <a href="tables.html#66">reversible container</a>, and an
73 * <a href="tables.html#69">associative container</a> (using equivalent
74 * keys). For a @c multiset<Key> the key_type and value_type are Key.
76 * Multisets support bidirectional iterators.
78 * The private tree data is declared exactly the same way for set and
79 * multiset; the distinction is made entirely in how the tree functions are
80 * called (*_unique versus *_equal, same as the standard).
82 template <typename _Key, typename _Compare = std::less<_Key>,
83 typename _Alloc = std::allocator<_Key> >
86 // concept requirements
87 typedef typename _Alloc::value_type _Alloc_value_type;
88 __glibcxx_class_requires(_Key, _SGIAssignableConcept)
89 __glibcxx_class_requires4(_Compare, bool, _Key, _Key,
90 _BinaryFunctionConcept)
91 __glibcxx_class_requires2(_Key, _Alloc_value_type, _SameTypeConcept)
95 typedef _Key key_type;
96 typedef _Key value_type;
97 typedef _Compare key_compare;
98 typedef _Compare value_compare;
99 typedef _Alloc allocator_type;
102 /// This turns a red-black tree into a [multi]set.
103 typedef typename _Alloc::template rebind<_Key>::other _Key_alloc_type;
105 typedef _Rb_tree<key_type, value_type, _Identity<value_type>,
106 key_compare, _Key_alloc_type> _Rep_type;
107 /// The actual tree structure.
111 typedef typename _Key_alloc_type::pointer pointer;
112 typedef typename _Key_alloc_type::const_pointer const_pointer;
113 typedef typename _Key_alloc_type::reference reference;
114 typedef typename _Key_alloc_type::const_reference const_reference;
115 // _GLIBCXX_RESOLVE_LIB_DEFECTS
116 // DR 103. set::iterator is required to be modifiable,
117 // but this allows modification of keys.
118 typedef typename _Rep_type::const_iterator iterator;
119 typedef typename _Rep_type::const_iterator const_iterator;
120 typedef typename _Rep_type::const_reverse_iterator reverse_iterator;
121 typedef typename _Rep_type::const_reverse_iterator const_reverse_iterator;
122 typedef typename _Rep_type::size_type size_type;
123 typedef typename _Rep_type::difference_type difference_type;
125 // allocation/deallocation
127 * @brief Default constructor creates no elements.
133 * @brief Creates a %multiset with no elements.
134 * @param comp Comparator to use.
135 * @param a An allocator object.
138 multiset(const _Compare& __comp,
139 const allocator_type& __a = allocator_type())
140 : _M_t(__comp, __a) { }
143 * @brief Builds a %multiset from a range.
144 * @param first An input iterator.
145 * @param last An input iterator.
147 * Create a %multiset consisting of copies of the elements from
148 * [first,last). This is linear in N if the range is already sorted,
149 * and NlogN otherwise (where N is distance(first,last)).
151 template<typename _InputIterator>
152 multiset(_InputIterator __first, _InputIterator __last)
154 { _M_t._M_insert_equal(__first, __last); }
157 * @brief Builds a %multiset from a range.
158 * @param first An input iterator.
159 * @param last An input iterator.
160 * @param comp A comparison functor.
161 * @param a An allocator object.
163 * Create a %multiset consisting of copies of the elements from
164 * [first,last). This is linear in N if the range is already sorted,
165 * and NlogN otherwise (where N is distance(first,last)).
167 template<typename _InputIterator>
168 multiset(_InputIterator __first, _InputIterator __last,
169 const _Compare& __comp,
170 const allocator_type& __a = allocator_type())
172 { _M_t._M_insert_equal(__first, __last); }
175 * @brief %Multiset copy constructor.
176 * @param x A %multiset of identical element and allocator types.
178 * The newly-created %multiset uses a copy of the allocation object used
181 multiset(const multiset& __x)
184 #ifdef __GXX_EXPERIMENTAL_CXX0X__
186 * @brief %Multiset move constructor.
187 * @param x A %multiset of identical element and allocator types.
189 * The newly-created %multiset contains the exact contents of @a x.
190 * The contents of @a x are a valid, but unspecified %multiset.
192 multiset(multiset&& __x)
193 : _M_t(std::forward<_Rep_type>(__x._M_t)) { }
196 * @brief Builds a %multiset from an initializer_list.
197 * @param l An initializer_list.
198 * @param comp A comparison functor.
199 * @param a An allocator object.
201 * Create a %multiset consisting of copies of the elements from
202 * the list. This is linear in N if the list is already sorted,
203 * and NlogN otherwise (where N is @a l.size()).
205 multiset(initializer_list<value_type> __l,
206 const _Compare& __comp = _Compare(),
207 const allocator_type& __a = allocator_type())
209 { _M_t._M_insert_equal(__l.begin(), __l.end()); }
213 * @brief %Multiset assignment operator.
214 * @param x A %multiset of identical element and allocator types.
216 * All the elements of @a x are copied, but unlike the copy constructor,
217 * the allocator object is not copied.
220 operator=(const multiset& __x)
226 #ifdef __GXX_EXPERIMENTAL_CXX0X__
228 * @brief %Multiset move assignment operator.
229 * @param x A %multiset of identical element and allocator types.
231 * The contents of @a x are moved into this %multiset (without copying).
232 * @a x is a valid, but unspecified %multiset.
235 operator=(multiset&& __x)
244 * @brief %Multiset list assignment operator.
245 * @param l An initializer_list.
247 * This function fills a %multiset with copies of the elements in the
248 * initializer list @a l.
250 * Note that the assignment completely changes the %multiset and
251 * that the resulting %multiset's size is the same as the number
252 * of elements assigned. Old data may be lost.
255 operator=(initializer_list<value_type> __l)
258 this->insert(__l.begin(), __l.end());
265 /// Returns the comparison object.
268 { return _M_t.key_comp(); }
269 /// Returns the comparison object.
272 { return _M_t.key_comp(); }
273 /// Returns the memory allocation object.
275 get_allocator() const
276 { return _M_t.get_allocator(); }
279 * Returns a read-only (constant) iterator that points to the first
280 * element in the %multiset. Iteration is done in ascending order
281 * according to the keys.
285 { return _M_t.begin(); }
288 * Returns a read-only (constant) iterator that points one past the last
289 * element in the %multiset. Iteration is done in ascending order
290 * according to the keys.
294 { return _M_t.end(); }
297 * Returns a read-only (constant) reverse iterator that points to the
298 * last element in the %multiset. Iteration is done in descending order
299 * according to the keys.
303 { return _M_t.rbegin(); }
306 * Returns a read-only (constant) reverse iterator that points to the
307 * last element in the %multiset. Iteration is done in descending order
308 * according to the keys.
312 { return _M_t.rend(); }
314 #ifdef __GXX_EXPERIMENTAL_CXX0X__
316 * Returns a read-only (constant) iterator that points to the first
317 * element in the %multiset. Iteration is done in ascending order
318 * according to the keys.
322 { return _M_t.begin(); }
325 * Returns a read-only (constant) iterator that points one past the last
326 * element in the %multiset. Iteration is done in ascending order
327 * according to the keys.
331 { return _M_t.end(); }
334 * Returns a read-only (constant) reverse iterator that points to the
335 * last element in the %multiset. Iteration is done in descending order
336 * according to the keys.
340 { return _M_t.rbegin(); }
343 * Returns a read-only (constant) reverse iterator that points to the
344 * last element in the %multiset. Iteration is done in descending order
345 * according to the keys.
349 { return _M_t.rend(); }
352 /// Returns true if the %set is empty.
355 { return _M_t.empty(); }
357 /// Returns the size of the %set.
360 { return _M_t.size(); }
362 /// Returns the maximum size of the %set.
365 { return _M_t.max_size(); }
368 * @brief Swaps data with another %multiset.
369 * @param x A %multiset of the same element and allocator types.
371 * This exchanges the elements between two multisets in constant time.
372 * (It is only swapping a pointer, an integer, and an instance of the @c
373 * Compare type (which itself is often stateless and empty), so it should
375 * Note that the global std::swap() function is specialized such that
376 * std::swap(s1,s2) will feed to this function.
380 { _M_t.swap(__x._M_t); }
384 * @brief Inserts an element into the %multiset.
385 * @param x Element to be inserted.
386 * @return An iterator that points to the inserted element.
388 * This function inserts an element into the %multiset. Contrary
389 * to a std::set the %multiset does not rely on unique keys and thus
390 * multiple copies of the same element can be inserted.
392 * Insertion requires logarithmic time.
395 insert(const value_type& __x)
396 { return _M_t._M_insert_equal(__x); }
399 * @brief Inserts an element into the %multiset.
400 * @param position An iterator that serves as a hint as to where the
401 * element should be inserted.
402 * @param x Element to be inserted.
403 * @return An iterator that points to the inserted element.
405 * This function inserts an element into the %multiset. Contrary
406 * to a std::set the %multiset does not rely on unique keys and thus
407 * multiple copies of the same element can be inserted.
409 * Note that the first parameter is only a hint and can potentially
410 * improve the performance of the insertion process. A bad hint would
411 * cause no gains in efficiency.
413 * See http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt07ch17.html
414 * for more on "hinting".
416 * Insertion requires logarithmic time (if the hint is not taken).
419 insert(iterator __position, const value_type& __x)
420 { return _M_t._M_insert_equal_(__position, __x); }
423 * @brief A template function that attempts to insert a range of elements.
424 * @param first Iterator pointing to the start of the range to be
426 * @param last Iterator pointing to the end of the range.
428 * Complexity similar to that of the range constructor.
430 template<typename _InputIterator>
432 insert(_InputIterator __first, _InputIterator __last)
433 { _M_t._M_insert_equal(__first, __last); }
435 #ifdef __GXX_EXPERIMENTAL_CXX0X__
437 * @brief Attempts to insert a list of elements into the %multiset.
438 * @param list A std::initializer_list<value_type> of elements
441 * Complexity similar to that of the range constructor.
444 insert(initializer_list<value_type> __l)
445 { this->insert(__l.begin(), __l.end()); }
449 * @brief Erases an element from a %multiset.
450 * @param position An iterator pointing to the element to be erased.
452 * This function erases an element, pointed to by the given iterator,
453 * from a %multiset. Note that this function only erases the element,
454 * and that if the element is itself a pointer, the pointed-to memory is
455 * not touched in any way. Managing the pointer is the user's
459 erase(iterator __position)
460 { _M_t.erase(__position); }
463 * @brief Erases elements according to the provided key.
464 * @param x Key of element to be erased.
465 * @return The number of elements erased.
467 * This function erases all elements located by the given key from a
469 * Note that this function only erases the element, and that if
470 * the element is itself a pointer, the pointed-to memory is not touched
471 * in any way. Managing the pointer is the user's responsibility.
474 erase(const key_type& __x)
475 { return _M_t.erase(__x); }
478 * @brief Erases a [first,last) range of elements from a %multiset.
479 * @param first Iterator pointing to the start of the range to be
481 * @param last Iterator pointing to the end of the range to be erased.
483 * This function erases a sequence of elements from a %multiset.
484 * Note that this function only erases the elements, and that if
485 * the elements themselves are pointers, the pointed-to memory is not
486 * touched in any way. Managing the pointer is the user's responsibility.
489 erase(iterator __first, iterator __last)
490 { _M_t.erase(__first, __last); }
493 * Erases all elements in a %multiset. Note that this function only
494 * erases the elements, and that if the elements themselves are pointers,
495 * the pointed-to memory is not touched in any way. Managing the pointer
496 * is the user's responsibility.
502 // multiset operations:
505 * @brief Finds the number of elements with given key.
506 * @param x Key of elements to be located.
507 * @return Number of elements with specified key.
510 count(const key_type& __x) const
511 { return _M_t.count(__x); }
513 // _GLIBCXX_RESOLVE_LIB_DEFECTS
514 // 214. set::find() missing const overload
517 * @brief Tries to locate an element in a %set.
518 * @param x Element to be located.
519 * @return Iterator pointing to sought-after element, or end() if not
522 * This function takes a key and tries to locate the element with which
523 * the key matches. If successful the function returns an iterator
524 * pointing to the sought after element. If unsuccessful it returns the
525 * past-the-end ( @c end() ) iterator.
528 find(const key_type& __x)
529 { return _M_t.find(__x); }
532 find(const key_type& __x) const
533 { return _M_t.find(__x); }
538 * @brief Finds the beginning of a subsequence matching given key.
539 * @param x Key to be located.
540 * @return Iterator pointing to first element equal to or greater
541 * than key, or end().
543 * This function returns the first element of a subsequence of elements
544 * that matches the given key. If unsuccessful it returns an iterator
545 * pointing to the first element that has a greater value than given key
546 * or end() if no such element exists.
549 lower_bound(const key_type& __x)
550 { return _M_t.lower_bound(__x); }
553 lower_bound(const key_type& __x) const
554 { return _M_t.lower_bound(__x); }
559 * @brief Finds the end of a subsequence matching given key.
560 * @param x Key to be located.
561 * @return Iterator pointing to the first element
562 * greater than key, or end().
565 upper_bound(const key_type& __x)
566 { return _M_t.upper_bound(__x); }
569 upper_bound(const key_type& __x) const
570 { return _M_t.upper_bound(__x); }
575 * @brief Finds a subsequence matching given key.
576 * @param x Key to be located.
577 * @return Pair of iterators that possibly points to the subsequence
578 * matching given key.
580 * This function is equivalent to
582 * std::make_pair(c.lower_bound(val),
583 * c.upper_bound(val))
585 * (but is faster than making the calls separately).
587 * This function probably only makes sense for multisets.
589 std::pair<iterator, iterator>
590 equal_range(const key_type& __x)
591 { return _M_t.equal_range(__x); }
593 std::pair<const_iterator, const_iterator>
594 equal_range(const key_type& __x) const
595 { return _M_t.equal_range(__x); }
597 template<typename _K1, typename _C1, typename _A1>
599 operator==(const multiset<_K1, _C1, _A1>&,
600 const multiset<_K1, _C1, _A1>&);
602 template<typename _K1, typename _C1, typename _A1>
604 operator< (const multiset<_K1, _C1, _A1>&,
605 const multiset<_K1, _C1, _A1>&);
609 * @brief Multiset equality comparison.
610 * @param x A %multiset.
611 * @param y A %multiset of the same type as @a x.
612 * @return True iff the size and elements of the multisets are equal.
614 * This is an equivalence relation. It is linear in the size of the
616 * Multisets are considered equivalent if their sizes are equal, and if
617 * corresponding elements compare equal.
619 template<typename _Key, typename _Compare, typename _Alloc>
621 operator==(const multiset<_Key, _Compare, _Alloc>& __x,
622 const multiset<_Key, _Compare, _Alloc>& __y)
623 { return __x._M_t == __y._M_t; }
626 * @brief Multiset ordering relation.
627 * @param x A %multiset.
628 * @param y A %multiset of the same type as @a x.
629 * @return True iff @a x is lexicographically less than @a y.
631 * This is a total ordering relation. It is linear in the size of the
632 * maps. The elements must be comparable with @c <.
634 * See std::lexicographical_compare() for how the determination is made.
636 template<typename _Key, typename _Compare, typename _Alloc>
638 operator<(const multiset<_Key, _Compare, _Alloc>& __x,
639 const multiset<_Key, _Compare, _Alloc>& __y)
640 { return __x._M_t < __y._M_t; }
642 /// Returns !(x == y).
643 template<typename _Key, typename _Compare, typename _Alloc>
645 operator!=(const multiset<_Key, _Compare, _Alloc>& __x,
646 const multiset<_Key, _Compare, _Alloc>& __y)
647 { return !(__x == __y); }
650 template<typename _Key, typename _Compare, typename _Alloc>
652 operator>(const multiset<_Key,_Compare,_Alloc>& __x,
653 const multiset<_Key,_Compare,_Alloc>& __y)
654 { return __y < __x; }
657 template<typename _Key, typename _Compare, typename _Alloc>
659 operator<=(const multiset<_Key, _Compare, _Alloc>& __x,
660 const multiset<_Key, _Compare, _Alloc>& __y)
661 { return !(__y < __x); }
664 template<typename _Key, typename _Compare, typename _Alloc>
666 operator>=(const multiset<_Key, _Compare, _Alloc>& __x,
667 const multiset<_Key, _Compare, _Alloc>& __y)
668 { return !(__x < __y); }
670 /// See std::multiset::swap().
671 template<typename _Key, typename _Compare, typename _Alloc>
673 swap(multiset<_Key, _Compare, _Alloc>& __x,
674 multiset<_Key, _Compare, _Alloc>& __y)
677 _GLIBCXX_END_NESTED_NAMESPACE
679 #endif /* _STL_MULTISET_H */