1 // Multimap implementation -*- C++ -*-
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52 /** @file stl_multimap.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_MULTIMAP_H
58 #define _STL_MULTIMAP_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 (key,value) pairs, which can be
67 * retrieved based on a key, 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 multimap<Key,T> the key_type is Key, the mapped_type
75 * is T, and the value_type is std::pair<const Key,T>.
77 * Multimaps support bidirectional iterators.
79 * The private tree data is declared exactly the same way for map and
80 * multimap; the distinction is made entirely in how the tree functions are
81 * called (*_unique versus *_equal, same as the standard).
83 template <typename _Key, typename _Tp,
84 typename _Compare = std::less<_Key>,
85 typename _Alloc = std::allocator<std::pair<const _Key, _Tp> > >
89 typedef _Key key_type;
90 typedef _Tp mapped_type;
91 typedef std::pair<const _Key, _Tp> value_type;
92 typedef _Compare key_compare;
93 typedef _Alloc allocator_type;
96 // concept requirements
97 typedef typename _Alloc::value_type _Alloc_value_type;
98 __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
99 __glibcxx_class_requires4(_Compare, bool, _Key, _Key,
100 _BinaryFunctionConcept)
101 __glibcxx_class_requires2(value_type, _Alloc_value_type, _SameTypeConcept)
105 : public std::binary_function<value_type, value_type, bool>
107 friend class multimap<_Key, _Tp, _Compare, _Alloc>;
111 value_compare(_Compare __c)
115 bool operator()(const value_type& __x, const value_type& __y) const
116 { return comp(__x.first, __y.first); }
120 /// This turns a red-black tree into a [multi]map.
121 typedef typename _Alloc::template rebind<value_type>::other
124 typedef _Rb_tree<key_type, value_type, _Select1st<value_type>,
125 key_compare, _Pair_alloc_type> _Rep_type;
126 /// The actual tree structure.
130 // many of these are specified differently in ISO, but the following are
131 // "functionally equivalent"
132 typedef typename _Pair_alloc_type::pointer pointer;
133 typedef typename _Pair_alloc_type::const_pointer const_pointer;
134 typedef typename _Pair_alloc_type::reference reference;
135 typedef typename _Pair_alloc_type::const_reference const_reference;
136 typedef typename _Rep_type::iterator iterator;
137 typedef typename _Rep_type::const_iterator const_iterator;
138 typedef typename _Rep_type::size_type size_type;
139 typedef typename _Rep_type::difference_type difference_type;
140 typedef typename _Rep_type::reverse_iterator reverse_iterator;
141 typedef typename _Rep_type::const_reverse_iterator const_reverse_iterator;
143 // [23.3.2] construct/copy/destroy
144 // (get_allocator() is also listed in this section)
146 * @brief Default constructor creates no elements.
152 * @brief Creates a %multimap with no elements.
153 * @param comp A comparison object.
154 * @param a An allocator object.
157 multimap(const _Compare& __comp,
158 const allocator_type& __a = allocator_type())
159 : _M_t(__comp, __a) { }
162 * @brief %Multimap copy constructor.
163 * @param x A %multimap of identical element and allocator types.
165 * The newly-created %multimap uses a copy of the allocation object
168 multimap(const multimap& __x)
171 #ifdef __GXX_EXPERIMENTAL_CXX0X__
173 * @brief %Multimap move constructor.
174 * @param x A %multimap of identical element and allocator types.
176 * The newly-created %multimap contains the exact contents of @a x.
177 * The contents of @a x are a valid, but unspecified %multimap.
179 multimap(multimap&& __x)
180 : _M_t(std::forward<_Rep_type>(__x._M_t)) { }
183 * @brief Builds a %multimap from an initializer_list.
184 * @param l An initializer_list.
185 * @param comp A comparison functor.
186 * @param a An allocator object.
188 * Create a %multimap consisting of copies of the elements from
189 * the initializer_list. This is linear in N if the list is already
190 * sorted, and NlogN otherwise (where N is @a __l.size()).
192 multimap(initializer_list<value_type> __l,
193 const _Compare& __comp = _Compare(),
194 const allocator_type& __a = allocator_type())
196 { _M_t._M_insert_equal(__l.begin(), __l.end()); }
200 * @brief Builds a %multimap from a range.
201 * @param first An input iterator.
202 * @param last An input iterator.
204 * Create a %multimap consisting of copies of the elements from
205 * [first,last). This is linear in N if the range is already sorted,
206 * and NlogN otherwise (where N is distance(first,last)).
208 template<typename _InputIterator>
209 multimap(_InputIterator __first, _InputIterator __last)
211 { _M_t._M_insert_equal(__first, __last); }
214 * @brief Builds a %multimap from a range.
215 * @param first An input iterator.
216 * @param last An input iterator.
217 * @param comp A comparison functor.
218 * @param a An allocator object.
220 * Create a %multimap consisting of copies of the elements from
221 * [first,last). This is linear in N if the range is already sorted,
222 * and NlogN otherwise (where N is distance(first,last)).
224 template<typename _InputIterator>
225 multimap(_InputIterator __first, _InputIterator __last,
226 const _Compare& __comp,
227 const allocator_type& __a = allocator_type())
229 { _M_t._M_insert_equal(__first, __last); }
231 // FIXME There is no dtor declared, but we should have something generated
232 // by Doxygen. I don't know what tags to add to this paragraph to make
235 * The dtor only erases the elements, and note that if the elements
236 * themselves are pointers, the pointed-to memory is not touched in any
237 * way. Managing the pointer is the user's responsibility.
241 * @brief %Multimap assignment operator.
242 * @param x A %multimap of identical element and allocator types.
244 * All the elements of @a x are copied, but unlike the copy constructor,
245 * the allocator object is not copied.
248 operator=(const multimap& __x)
254 #ifdef __GXX_EXPERIMENTAL_CXX0X__
256 * @brief %Multimap move assignment operator.
257 * @param x A %multimap of identical element and allocator types.
259 * The contents of @a x are moved into this multimap (without copying).
260 * @a x is a valid, but unspecified multimap.
263 operator=(multimap&& __x)
272 * @brief %Multimap list assignment operator.
273 * @param l An initializer_list.
275 * This function fills a %multimap with copies of the elements
276 * in the initializer list @a l.
278 * Note that the assignment completely changes the %multimap and
279 * that the resulting %multimap's size is the same as the number
280 * of elements assigned. Old data may be lost.
283 operator=(initializer_list<value_type> __l)
286 this->insert(__l.begin(), __l.end());
291 /// Get a copy of the memory allocation object.
293 get_allocator() const
294 { return _M_t.get_allocator(); }
298 * Returns a read/write iterator that points to the first pair in the
299 * %multimap. Iteration is done in ascending order according to the
304 { return _M_t.begin(); }
307 * Returns a read-only (constant) iterator that points to the first pair
308 * in the %multimap. Iteration is done in ascending order according to
313 { return _M_t.begin(); }
316 * Returns a read/write iterator that points one past the last pair in
317 * the %multimap. Iteration is done in ascending order according to the
322 { return _M_t.end(); }
325 * Returns a read-only (constant) iterator that points one past the last
326 * pair in the %multimap. Iteration is done in ascending order according
331 { return _M_t.end(); }
334 * Returns a read/write reverse iterator that points to the last pair in
335 * the %multimap. Iteration is done in descending order according to the
340 { return _M_t.rbegin(); }
343 * Returns a read-only (constant) reverse iterator that points to the
344 * last pair in the %multimap. Iteration is done in descending order
345 * according to the keys.
347 const_reverse_iterator
349 { return _M_t.rbegin(); }
352 * Returns a read/write reverse iterator that points to one before the
353 * first pair in the %multimap. Iteration is done in descending order
354 * according to the keys.
358 { return _M_t.rend(); }
361 * Returns a read-only (constant) reverse iterator that points to one
362 * before the first pair in the %multimap. Iteration is done in
363 * descending order according to the keys.
365 const_reverse_iterator
367 { return _M_t.rend(); }
369 #ifdef __GXX_EXPERIMENTAL_CXX0X__
371 * Returns a read-only (constant) iterator that points to the first pair
372 * in the %multimap. Iteration is done in ascending order according to
377 { return _M_t.begin(); }
380 * Returns a read-only (constant) iterator that points one past the last
381 * pair in the %multimap. Iteration is done in ascending order according
386 { return _M_t.end(); }
389 * Returns a read-only (constant) reverse iterator that points to the
390 * last pair in the %multimap. Iteration is done in descending order
391 * according to the keys.
393 const_reverse_iterator
395 { return _M_t.rbegin(); }
398 * Returns a read-only (constant) reverse iterator that points to one
399 * before the first pair in the %multimap. Iteration is done in
400 * descending order according to the keys.
402 const_reverse_iterator
404 { return _M_t.rend(); }
408 /** Returns true if the %multimap is empty. */
411 { return _M_t.empty(); }
413 /** Returns the size of the %multimap. */
416 { return _M_t.size(); }
418 /** Returns the maximum size of the %multimap. */
421 { return _M_t.max_size(); }
425 * @brief Inserts a std::pair into the %multimap.
426 * @param x Pair to be inserted (see std::make_pair for easy creation
428 * @return An iterator that points to the inserted (key,value) pair.
430 * This function inserts a (key, value) pair into the %multimap.
431 * Contrary to a std::map the %multimap does not rely on unique keys and
432 * thus multiple pairs with the same key can be inserted.
434 * Insertion requires logarithmic time.
437 insert(const value_type& __x)
438 { return _M_t._M_insert_equal(__x); }
441 * @brief Inserts a std::pair into the %multimap.
442 * @param position An iterator that serves as a hint as to where the
443 * pair should be inserted.
444 * @param x Pair to be inserted (see std::make_pair for easy creation
446 * @return An iterator that points to the inserted (key,value) pair.
448 * This function inserts a (key, value) pair into the %multimap.
449 * Contrary to a std::map the %multimap does not rely on unique keys and
450 * thus multiple pairs with the same key can be inserted.
451 * Note that the first parameter is only a hint and can potentially
452 * improve the performance of the insertion process. A bad hint would
453 * cause no gains in efficiency.
455 * For more on "hinting," see:
456 * http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt07ch17.html
458 * Insertion requires logarithmic time (if the hint is not taken).
461 insert(iterator __position, const value_type& __x)
462 { return _M_t._M_insert_equal_(__position, __x); }
465 * @brief A template function that attempts to insert a range
467 * @param first Iterator pointing to the start of the range to be
469 * @param last Iterator pointing to the end of the range.
471 * Complexity similar to that of the range constructor.
473 template<typename _InputIterator>
475 insert(_InputIterator __first, _InputIterator __last)
476 { _M_t._M_insert_equal(__first, __last); }
478 #ifdef __GXX_EXPERIMENTAL_CXX0X__
480 * @brief Attempts to insert a list of std::pairs into the %multimap.
481 * @param list A std::initializer_list<value_type> of pairs to be
484 * Complexity similar to that of the range constructor.
487 insert(initializer_list<value_type> __l)
488 { this->insert(__l.begin(), __l.end()); }
492 * @brief Erases an element from a %multimap.
493 * @param position An iterator pointing to the element to be erased.
495 * This function erases an element, pointed to by the given iterator,
496 * from a %multimap. Note that this function only erases the element,
497 * and that if the element is itself a pointer, the pointed-to memory is
498 * not touched in any way. Managing the pointer is the user's
502 erase(iterator __position)
503 { _M_t.erase(__position); }
506 * @brief Erases elements according to the provided key.
507 * @param x Key of element to be erased.
508 * @return The number of elements erased.
510 * This function erases all elements located by the given key from a
512 * Note that this function only erases the element, and that if
513 * the element is itself a pointer, the pointed-to memory is not touched
514 * in any way. Managing the pointer is the user's responsibility.
517 erase(const key_type& __x)
518 { return _M_t.erase(__x); }
521 * @brief Erases a [first,last) range of elements from a %multimap.
522 * @param first Iterator pointing to the start of the range to be
524 * @param last Iterator pointing to the end of the range to be erased.
526 * This function erases a sequence of elements from a %multimap.
527 * Note that this function only erases the elements, and that if
528 * the elements themselves are pointers, the pointed-to memory is not
529 * touched in any way. Managing the pointer is the user's responsibility.
532 erase(iterator __first, iterator __last)
533 { _M_t.erase(__first, __last); }
536 * @brief Swaps data with another %multimap.
537 * @param x A %multimap of the same element and allocator types.
539 * This exchanges the elements between two multimaps in constant time.
540 * (It is only swapping a pointer, an integer, and an instance of
541 * the @c Compare type (which itself is often stateless and empty), so it
542 * should be quite fast.)
543 * Note that the global std::swap() function is specialized such that
544 * std::swap(m1,m2) will feed to this function.
548 { _M_t.swap(__x._M_t); }
551 * Erases all elements in a %multimap. Note that this function only
552 * erases the elements, and that if the elements themselves are pointers,
553 * the pointed-to memory is not touched in any way. Managing the pointer
554 * is the user's responsibility.
562 * Returns the key comparison object out of which the %multimap
567 { return _M_t.key_comp(); }
570 * Returns a value comparison object, built from the key comparison
571 * object out of which the %multimap was constructed.
575 { return value_compare(_M_t.key_comp()); }
577 // multimap operations
579 * @brief Tries to locate an element in a %multimap.
580 * @param x Key of (key, value) pair to be located.
581 * @return Iterator pointing to sought-after element,
582 * or end() if not found.
584 * This function takes a key and tries to locate the element with which
585 * the key matches. If successful the function returns an iterator
586 * pointing to the sought after %pair. If unsuccessful it returns the
587 * past-the-end ( @c end() ) iterator.
590 find(const key_type& __x)
591 { return _M_t.find(__x); }
594 * @brief Tries to locate an element in a %multimap.
595 * @param x Key of (key, value) pair to be located.
596 * @return Read-only (constant) iterator pointing to sought-after
597 * element, or end() if not found.
599 * This function takes a key and tries to locate the element with which
600 * the key matches. If successful the function returns a constant
601 * iterator pointing to the sought after %pair. If unsuccessful it
602 * returns the past-the-end ( @c end() ) iterator.
605 find(const key_type& __x) const
606 { return _M_t.find(__x); }
609 * @brief Finds the number of elements with given key.
610 * @param x Key of (key, value) pairs to be located.
611 * @return Number of elements with specified key.
614 count(const key_type& __x) const
615 { return _M_t.count(__x); }
618 * @brief Finds the beginning of a subsequence matching given key.
619 * @param x Key of (key, value) pair to be located.
620 * @return Iterator pointing to first element equal to or greater
621 * than key, or end().
623 * This function returns the first element of a subsequence of elements
624 * that matches the given key. If unsuccessful it returns an iterator
625 * pointing to the first element that has a greater value than given key
626 * or end() if no such element exists.
629 lower_bound(const key_type& __x)
630 { return _M_t.lower_bound(__x); }
633 * @brief Finds the beginning of a subsequence matching given key.
634 * @param x Key of (key, value) pair to be located.
635 * @return Read-only (constant) iterator pointing to first element
636 * equal to or greater than key, or end().
638 * This function returns the first element of a subsequence of elements
639 * that matches the given key. If unsuccessful the iterator will point
640 * to the next greatest element or, if no such greater element exists, to
644 lower_bound(const key_type& __x) const
645 { return _M_t.lower_bound(__x); }
648 * @brief Finds the end of a subsequence matching given key.
649 * @param x Key of (key, value) pair to be located.
650 * @return Iterator pointing to the first element
651 * greater than key, or end().
654 upper_bound(const key_type& __x)
655 { return _M_t.upper_bound(__x); }
658 * @brief Finds the end of a subsequence matching given key.
659 * @param x Key of (key, value) pair to be located.
660 * @return Read-only (constant) iterator pointing to first iterator
661 * greater than key, or end().
664 upper_bound(const key_type& __x) const
665 { return _M_t.upper_bound(__x); }
668 * @brief Finds a subsequence matching given key.
669 * @param x Key of (key, value) pairs to be located.
670 * @return Pair of iterators that possibly points to the subsequence
671 * matching given key.
673 * This function is equivalent to
675 * std::make_pair(c.lower_bound(val),
676 * c.upper_bound(val))
678 * (but is faster than making the calls separately).
680 std::pair<iterator, iterator>
681 equal_range(const key_type& __x)
682 { return _M_t.equal_range(__x); }
685 * @brief Finds a subsequence matching given key.
686 * @param x Key of (key, value) pairs to be located.
687 * @return Pair of read-only (constant) iterators that possibly points
688 * to the subsequence matching given key.
690 * This function is equivalent to
692 * std::make_pair(c.lower_bound(val),
693 * c.upper_bound(val))
695 * (but is faster than making the calls separately).
697 std::pair<const_iterator, const_iterator>
698 equal_range(const key_type& __x) const
699 { return _M_t.equal_range(__x); }
701 template<typename _K1, typename _T1, typename _C1, typename _A1>
703 operator==(const multimap<_K1, _T1, _C1, _A1>&,
704 const multimap<_K1, _T1, _C1, _A1>&);
706 template<typename _K1, typename _T1, typename _C1, typename _A1>
708 operator<(const multimap<_K1, _T1, _C1, _A1>&,
709 const multimap<_K1, _T1, _C1, _A1>&);
713 * @brief Multimap equality comparison.
714 * @param x A %multimap.
715 * @param y A %multimap of the same type as @a x.
716 * @return True iff the size and elements of the maps are equal.
718 * This is an equivalence relation. It is linear in the size of the
719 * multimaps. Multimaps are considered equivalent if their sizes are equal,
720 * and if corresponding elements compare equal.
722 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
724 operator==(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
725 const multimap<_Key, _Tp, _Compare, _Alloc>& __y)
726 { return __x._M_t == __y._M_t; }
729 * @brief Multimap ordering relation.
730 * @param x A %multimap.
731 * @param y A %multimap of the same type as @a x.
732 * @return True iff @a x is lexicographically less than @a y.
734 * This is a total ordering relation. It is linear in the size of the
735 * multimaps. The elements must be comparable with @c <.
737 * See std::lexicographical_compare() for how the determination is made.
739 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
741 operator<(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
742 const multimap<_Key, _Tp, _Compare, _Alloc>& __y)
743 { return __x._M_t < __y._M_t; }
745 /// Based on operator==
746 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
748 operator!=(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
749 const multimap<_Key, _Tp, _Compare, _Alloc>& __y)
750 { return !(__x == __y); }
752 /// Based on operator<
753 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
755 operator>(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
756 const multimap<_Key, _Tp, _Compare, _Alloc>& __y)
757 { return __y < __x; }
759 /// Based on operator<
760 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
762 operator<=(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
763 const multimap<_Key, _Tp, _Compare, _Alloc>& __y)
764 { return !(__y < __x); }
766 /// Based on operator<
767 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
769 operator>=(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
770 const multimap<_Key, _Tp, _Compare, _Alloc>& __y)
771 { return !(__x < __y); }
773 /// See std::multimap::swap().
774 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
776 swap(multimap<_Key, _Tp, _Compare, _Alloc>& __x,
777 multimap<_Key, _Tp, _Compare, _Alloc>& __y)
780 _GLIBCXX_END_NESTED_NAMESPACE
782 #endif /* _STL_MULTIMAP_H */