1 // Multiset implementation -*- C++ -*-
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56 /** @file stl_multiset.h
57 * This is an internal header file, included by other library headers.
58 * You should not attempt to use it directly.
64 #include <bits/concept_check.h>
66 _GLIBCXX_BEGIN_NESTED_NAMESPACE(std, _GLIBCXX_STD)
69 * @brief A standard container made up of elements, which can be retrieved
70 * in logarithmic time.
73 * @ingroup Assoc_containers
75 * Meets the requirements of a <a href="tables.html#65">container</a>, a
76 * <a href="tables.html#66">reversible container</a>, and an
77 * <a href="tables.html#69">associative container</a> (using equivalent
78 * keys). For a @c multiset<Key> the key_type and value_type are Key.
80 * Multisets support bidirectional iterators.
83 * The private tree data is declared exactly the same way for set and
84 * multiset; the distinction is made entirely in how the tree functions are
85 * called (*_unique versus *_equal, same as the standard).
88 template <class _Key, class _Compare = std::less<_Key>,
89 class _Alloc = std::allocator<_Key> >
92 // concept requirements
93 typedef typename _Alloc::value_type _Alloc_value_type;
94 __glibcxx_class_requires(_Key, _SGIAssignableConcept)
95 __glibcxx_class_requires4(_Compare, bool, _Key, _Key,
96 _BinaryFunctionConcept)
97 __glibcxx_class_requires2(_Key, _Alloc_value_type, _SameTypeConcept)
101 typedef _Key key_type;
102 typedef _Key value_type;
103 typedef _Compare key_compare;
104 typedef _Compare value_compare;
105 typedef _Alloc allocator_type;
108 /// @if maint This turns a red-black tree into a [multi]set. @endif
109 typedef typename _Alloc::template rebind<_Key>::other _Key_alloc_type;
111 typedef _Rb_tree<key_type, value_type, _Identity<value_type>,
112 key_compare, _Key_alloc_type> _Rep_type;
113 /// @if maint The actual tree structure. @endif
117 typedef typename _Key_alloc_type::pointer pointer;
118 typedef typename _Key_alloc_type::const_pointer const_pointer;
119 typedef typename _Key_alloc_type::reference reference;
120 typedef typename _Key_alloc_type::const_reference const_reference;
121 // _GLIBCXX_RESOLVE_LIB_DEFECTS
122 // DR 103. set::iterator is required to be modifiable,
123 // but this allows modification of keys.
124 typedef typename _Rep_type::const_iterator iterator;
125 typedef typename _Rep_type::const_iterator const_iterator;
126 typedef typename _Rep_type::const_reverse_iterator reverse_iterator;
127 typedef typename _Rep_type::const_reverse_iterator const_reverse_iterator;
128 typedef typename _Rep_type::size_type size_type;
129 typedef typename _Rep_type::difference_type difference_type;
131 // allocation/deallocation
134 * @brief Default constructor creates no elements.
140 multiset(const _Compare& __comp,
141 const allocator_type& __a = allocator_type())
142 : _M_t(__comp, __a) { }
145 * @brief Builds a %multiset from a range.
146 * @param first An input iterator.
147 * @param last An input iterator.
149 * Create a %multiset consisting of copies of the elements from
150 * [first,last). This is linear in N if the range is already sorted,
151 * and NlogN otherwise (where N is distance(first,last)).
153 template <class _InputIterator>
154 multiset(_InputIterator __first, _InputIterator __last)
156 { _M_t._M_insert_equal(__first, __last); }
159 * @brief Builds a %multiset from a range.
160 * @param first An input iterator.
161 * @param last An input iterator.
162 * @param comp A comparison functor.
163 * @param a An allocator object.
165 * Create a %multiset consisting of copies of the elements from
166 * [first,last). This is linear in N if the range is already sorted,
167 * and NlogN otherwise (where N is distance(first,last)).
169 template <class _InputIterator>
170 multiset(_InputIterator __first, _InputIterator __last,
171 const _Compare& __comp,
172 const allocator_type& __a = allocator_type())
174 { _M_t._M_insert_equal(__first, __last); }
177 * @brief %Multiset copy constructor.
178 * @param x A %multiset of identical element and allocator types.
180 * The newly-created %multiset uses a copy of the allocation object used
183 multiset(const multiset& __x)
187 * @brief %Multiset assignment operator.
188 * @param x A %multiset of identical element and allocator types.
190 * All the elements of @a x are copied, but unlike the copy constructor,
191 * the allocator object is not copied.
194 operator=(const multiset& __x)
202 /// Returns the comparison object.
205 { return _M_t.key_comp(); }
206 /// Returns the comparison object.
209 { return _M_t.key_comp(); }
210 /// Returns the memory allocation object.
212 get_allocator() const
213 { return _M_t.get_allocator(); }
216 * Returns a read/write iterator that points to the first element in the
217 * %multiset. Iteration is done in ascending order according to the
222 { return _M_t.begin(); }
225 * Returns a read/write iterator that points one past the last element in
226 * the %multiset. Iteration is done in ascending order according to the
231 { return _M_t.end(); }
234 * Returns a read/write reverse iterator that points to the last element
235 * in the %multiset. Iteration is done in descending order according to
240 { return _M_t.rbegin(); }
243 * Returns a read/write reverse iterator that points to the last element
244 * in the %multiset. Iteration is done in descending order according to
249 { return _M_t.rend(); }
251 /// Returns true if the %set is empty.
254 { return _M_t.empty(); }
256 /// Returns the size of the %set.
259 { return _M_t.size(); }
261 /// Returns the maximum size of the %set.
264 { return _M_t.max_size(); }
267 * @brief Swaps data with another %multiset.
268 * @param x A %multiset of the same element and allocator types.
270 * This exchanges the elements between two multisets in constant time.
271 * (It is only swapping a pointer, an integer, and an instance of the @c
272 * Compare type (which itself is often stateless and empty), so it should
274 * Note that the global std::swap() function is specialized such that
275 * std::swap(s1,s2) will feed to this function.
279 { _M_t.swap(__x._M_t); }
283 * @brief Inserts an element into the %multiset.
284 * @param x Element to be inserted.
285 * @return An iterator that points to the inserted element.
287 * This function inserts an element into the %multiset. Contrary
288 * to a std::set the %multiset does not rely on unique keys and thus
289 * multiple copies of the same element can be inserted.
291 * Insertion requires logarithmic time.
294 insert(const value_type& __x)
295 { return _M_t._M_insert_equal(__x); }
298 * @brief Inserts an element into the %multiset.
299 * @param position An iterator that serves as a hint as to where the
300 * element should be inserted.
301 * @param x Element to be inserted.
302 * @return An iterator that points to the inserted element.
304 * This function inserts an element into the %multiset. Contrary
305 * to a std::set the %multiset does not rely on unique keys and thus
306 * multiple copies of the same element can be inserted.
308 * Note that the first parameter is only a hint and can potentially
309 * improve the performance of the insertion process. A bad hint would
310 * cause no gains in efficiency.
312 * See http://gcc.gnu.org/onlinedocs/libstdc++/23_containers/howto.html#4
313 * for more on "hinting".
315 * Insertion requires logarithmic time (if the hint is not taken).
318 insert(iterator __position, const value_type& __x)
319 { return _M_t._M_insert_equal(__position, __x); }
322 * @brief A template function that attemps to insert a range of elements.
323 * @param first Iterator pointing to the start of the range to be
325 * @param last Iterator pointing to the end of the range.
327 * Complexity similar to that of the range constructor.
329 template <class _InputIterator>
331 insert(_InputIterator __first, _InputIterator __last)
332 { _M_t._M_insert_equal(__first, __last); }
335 * @brief Erases an element from a %multiset.
336 * @param position An iterator pointing to the element to be erased.
338 * This function erases an element, pointed to by the given iterator,
339 * from a %multiset. Note that this function only erases the element,
340 * and that if the element is itself a pointer, the pointed-to memory is
341 * not touched in any way. Managing the pointer is the user's
345 erase(iterator __position)
346 { _M_t.erase(__position); }
349 * @brief Erases elements according to the provided key.
350 * @param x Key of element to be erased.
351 * @return The number of elements erased.
353 * This function erases all elements located by the given key from a
355 * Note that this function only erases the element, and that if
356 * the element is itself a pointer, the pointed-to memory is not touched
357 * in any way. Managing the pointer is the user's responsibilty.
360 erase(const key_type& __x)
361 { return _M_t.erase(__x); }
364 * @brief Erases a [first,last) range of elements from a %multiset.
365 * @param first Iterator pointing to the start of the range to be
367 * @param last Iterator pointing to the end of the range to be erased.
369 * This function erases a sequence of elements from a %multiset.
370 * Note that this function only erases the elements, and that if
371 * the elements themselves are pointers, the pointed-to memory is not
372 * touched in any way. Managing the pointer is the user's responsibilty.
375 erase(iterator __first, iterator __last)
376 { _M_t.erase(__first, __last); }
379 * Erases all elements in a %multiset. Note that this function only
380 * erases the elements, and that if the elements themselves are pointers,
381 * the pointed-to memory is not touched in any way. Managing the pointer
382 * is the user's responsibilty.
388 // multiset operations:
391 * @brief Finds the number of elements with given key.
392 * @param x Key of elements to be located.
393 * @return Number of elements with specified key.
396 count(const key_type& __x) const
397 { return _M_t.count(__x); }
399 // _GLIBCXX_RESOLVE_LIB_DEFECTS
400 // 214. set::find() missing const overload
403 * @brief Tries to locate an element in a %set.
404 * @param x Element to be located.
405 * @return Iterator pointing to sought-after element, or end() if not
408 * This function takes a key and tries to locate the element with which
409 * the key matches. If successful the function returns an iterator
410 * pointing to the sought after element. If unsuccessful it returns the
411 * past-the-end ( @c end() ) iterator.
414 find(const key_type& __x)
415 { return _M_t.find(__x); }
418 find(const key_type& __x) const
419 { return _M_t.find(__x); }
424 * @brief Finds the beginning of a subsequence matching given key.
425 * @param x Key to be located.
426 * @return Iterator pointing to first element equal to or greater
427 * than key, or end().
429 * This function returns the first element of a subsequence of elements
430 * that matches the given key. If unsuccessful it returns an iterator
431 * pointing to the first element that has a greater value than given key
432 * or end() if no such element exists.
435 lower_bound(const key_type& __x)
436 { return _M_t.lower_bound(__x); }
439 lower_bound(const key_type& __x) const
440 { return _M_t.lower_bound(__x); }
445 * @brief Finds the end of a subsequence matching given key.
446 * @param x Key to be located.
447 * @return Iterator pointing to the first element
448 * greater than key, or end().
451 upper_bound(const key_type& __x)
452 { return _M_t.upper_bound(__x); }
455 upper_bound(const key_type& __x) const
456 { return _M_t.upper_bound(__x); }
461 * @brief Finds a subsequence matching given key.
462 * @param x Key to be located.
463 * @return Pair of iterators that possibly points to the subsequence
464 * matching given key.
466 * This function is equivalent to
468 * std::make_pair(c.lower_bound(val),
469 * c.upper_bound(val))
471 * (but is faster than making the calls separately).
473 * This function probably only makes sense for multisets.
475 std::pair<iterator, iterator>
476 equal_range(const key_type& __x)
477 { return _M_t.equal_range(__x); }
479 std::pair<const_iterator, const_iterator>
480 equal_range(const key_type& __x) const
481 { return _M_t.equal_range(__x); }
483 template <class _K1, class _C1, class _A1>
485 operator== (const multiset<_K1, _C1, _A1>&,
486 const multiset<_K1, _C1, _A1>&);
488 template <class _K1, class _C1, class _A1>
490 operator< (const multiset<_K1, _C1, _A1>&,
491 const multiset<_K1, _C1, _A1>&);
495 * @brief Multiset equality comparison.
496 * @param x A %multiset.
497 * @param y A %multiset of the same type as @a x.
498 * @return True iff the size and elements of the multisets are equal.
500 * This is an equivalence relation. It is linear in the size of the
502 * Multisets are considered equivalent if their sizes are equal, and if
503 * corresponding elements compare equal.
505 template <class _Key, class _Compare, class _Alloc>
507 operator==(const multiset<_Key, _Compare, _Alloc>& __x,
508 const multiset<_Key, _Compare, _Alloc>& __y)
509 { return __x._M_t == __y._M_t; }
512 * @brief Multiset ordering relation.
513 * @param x A %multiset.
514 * @param y A %multiset of the same type as @a x.
515 * @return True iff @a x is lexicographically less than @a y.
517 * This is a total ordering relation. It is linear in the size of the
518 * maps. The elements must be comparable with @c <.
520 * See std::lexicographical_compare() for how the determination is made.
522 template <class _Key, class _Compare, class _Alloc>
524 operator<(const multiset<_Key, _Compare, _Alloc>& __x,
525 const multiset<_Key, _Compare, _Alloc>& __y)
526 { return __x._M_t < __y._M_t; }
528 /// Returns !(x == y).
529 template <class _Key, class _Compare, class _Alloc>
531 operator!=(const multiset<_Key, _Compare, _Alloc>& __x,
532 const multiset<_Key, _Compare, _Alloc>& __y)
533 { return !(__x == __y); }
536 template <class _Key, class _Compare, class _Alloc>
538 operator>(const multiset<_Key,_Compare,_Alloc>& __x,
539 const multiset<_Key,_Compare,_Alloc>& __y)
540 { return __y < __x; }
543 template <class _Key, class _Compare, class _Alloc>
545 operator<=(const multiset<_Key, _Compare, _Alloc>& __x,
546 const multiset<_Key, _Compare, _Alloc>& __y)
547 { return !(__y < __x); }
550 template <class _Key, class _Compare, class _Alloc>
552 operator>=(const multiset<_Key, _Compare, _Alloc>& __x,
553 const multiset<_Key, _Compare, _Alloc>& __y)
554 { return !(__x < __y); }
556 /// See std::multiset::swap().
557 template <class _Key, class _Compare, class _Alloc>
559 swap(multiset<_Key, _Compare, _Alloc>& __x,
560 multiset<_Key, _Compare, _Alloc>& __y)
563 _GLIBCXX_END_NESTED_NAMESPACE
565 #endif /* _MULTISET_H */