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1 // Multimap implementation -*- C++ -*-
2
3 // Copyright (C) 2001, 2002 Free Software Foundation, Inc.
4 //
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 2, or (at your option)
9 // any later version.
10
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.
15
16 // You should have received a copy of the GNU General Public License along
17 // with this library; see the file COPYING. If not, write to the Free
18 // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
19 // USA.
20
21 // As a special exception, you may use this file as part of a free software
22 // library without restriction. Specifically, if other files instantiate
23 // templates or use macros or inline functions from this file, or you compile
24 // this file and link it with other files to produce an executable, this
25 // file does not by itself cause the resulting executable to be covered by
26 // the GNU General Public License. This exception does not however
27 // invalidate any other reasons why the executable file might be covered by
28 // the GNU General Public License.
29
30 /*
31 *
32 * Copyright (c) 1994
33 * Hewlett-Packard Company
34 *
35 * Permission to use, copy, modify, distribute and sell this software
36 * and its documentation for any purpose is hereby granted without fee,
37 * provided that the above copyright notice appear in all copies and
38 * that both that copyright notice and this permission notice appear
39 * in supporting documentation. Hewlett-Packard Company makes no
40 * representations about the suitability of this software for any
41 * purpose. It is provided "as is" without express or implied warranty.
42 *
43 *
44 * Copyright (c) 1996,1997
45 * Silicon Graphics Computer Systems, Inc.
46 *
47 * Permission to use, copy, modify, distribute and sell this software
48 * and its documentation for any purpose is hereby granted without fee,
49 * provided that the above copyright notice appear in all copies and
50 * that both that copyright notice and this permission notice appear
51 * in supporting documentation. Silicon Graphics makes no
52 * representations about the suitability of this software for any
53 * purpose. It is provided "as is" without express or implied warranty.
54 */
55
56 /** @file stl_multimap.h
57 * This is an internal header file, included by other library headers.
58 * You should not attempt to use it directly.
59 */
60
61 #ifndef _MULTIMAP_H
62 #define _MULTIMAP_H 1
63
64 #include <bits/concept_check.h>
65
66 namespace std
67 {
68 // Forward declaration of operators < and ==, needed for friend declaration.
69
70 template <typename _Key, typename _Tp,
71 typename _Compare = less<_Key>,
72 typename _Alloc = allocator<pair<const _Key, _Tp> > >
73 class multimap;
74
75 template <typename _Key, typename _Tp, typename _Compare, typename _Alloc>
76 inline bool operator==(const multimap<_Key,_Tp,_Compare,_Alloc>& __x,
77 const multimap<_Key,_Tp,_Compare,_Alloc>& __y);
78
79 template <typename _Key, typename _Tp, typename _Compare, typename _Alloc>
80 inline bool operator<(const multimap<_Key,_Tp,_Compare,_Alloc>& __x,
81 const multimap<_Key,_Tp,_Compare,_Alloc>& __y);
82
83 /**
84 * @brief A standard container made up of (key,value) pairs, which can be
85 * retrieved based on a key, in logarithmic time.
86 *
87 * @ingroup Containers
88 * @ingroup Assoc_containers
89 *
90 * Meets the requirements of a <a href="tables.html#65">container</a>, a
91 * <a href="tables.html#66">reversible container</a>, and an
92 * <a href="tables.html#69">associative container</a> (using equivalent
93 * keys). For a @c multimap<Key,T> the key_type is Key, the mapped_type
94 * is T, and the value_type is std::pair<const Key,T>.
95 *
96 * Multimaps support bidirectional iterators.
97 *
98 * @if maint
99 * The private tree data is declared exactly the same way for map and
100 * multimap; the distinction is made entirely in how the tree functions are
101 * called (*_unique versus *_equal, same as the standard).
102 * @endif
103 */
104 template <typename _Key, typename _Tp, typename _Compare, typename _Alloc>
105 class multimap
106 {
107 // concept requirements
108 __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
109 __glibcxx_class_requires4(_Compare, bool, _Key, _Key, _BinaryFunctionConcept)
110
111 public:
112 typedef _Key key_type;
113 typedef _Tp mapped_type;
114 typedef pair<const _Key, _Tp> value_type;
115 typedef _Compare key_compare;
116
117 class value_compare
118 : public binary_function<value_type, value_type, bool>
119 {
120 friend class multimap<_Key,_Tp,_Compare,_Alloc>;
121 protected:
122 _Compare comp;
123 value_compare(_Compare __c) : comp(__c) {}
124 public:
125 bool operator()(const value_type& __x, const value_type& __y) const
126 { return comp(__x.first, __y.first); }
127 };
128
129 private:
130 /// @if maint This turns a red-black tree into a [multi]map. @endif
131 typedef _Rb_tree<key_type, value_type,
132 _Select1st<value_type>, key_compare, _Alloc> _Rep_type;
133 /// @if maint The actual tree structure. @endif
134 _Rep_type _M_t;
135
136 public:
137 // many of these are specified differently in ISO, but the following are
138 // "functionally equivalent"
139 typedef typename _Rep_type::allocator_type allocator_type;
140 typedef typename _Rep_type::reference reference;
141 typedef typename _Rep_type::const_reference const_reference;
142 typedef typename _Rep_type::iterator iterator;
143 typedef typename _Rep_type::const_iterator const_iterator;
144 typedef typename _Rep_type::size_type size_type;
145 typedef typename _Rep_type::difference_type difference_type;
146 typedef typename _Rep_type::pointer pointer;
147 typedef typename _Rep_type::const_pointer const_pointer;
148 typedef typename _Rep_type::reverse_iterator reverse_iterator;
149 typedef typename _Rep_type::const_reverse_iterator const_reverse_iterator;
150
151
152 // [23.3.2] construct/copy/destroy
153 // (get_allocator() is also listed in this section)
154 /**
155 * @brief Default constructor creates no elements.
156 */
157 multimap() : _M_t(_Compare(), allocator_type()) { }
158
159 // for some reason this was made a separate function
160 /**
161 * @brief Default constructor creates no elements.
162 */
163 explicit
164 multimap(const _Compare& __comp, const allocator_type& __a = allocator_type())
165 : _M_t(__comp, __a) { }
166
167 /**
168 * @brief %Multimap copy constructor.
169 * @param x A %multimap of identical element and allocator types.
170 *
171 * The newly-created %multimap uses a copy of the allocation object used
172 * by @a x.
173 */
174 multimap(const multimap& __x)
175 : _M_t(__x._M_t) { }
176
177 /**
178 * @brief Builds a %multimap from a range.
179 * @param first An input iterator.
180 * @param last An input iterator.
181 *
182 * Create a %multimap consisting of copies of the elements from
183 * [first,last). This is linear in N if the range is already sorted,
184 * and NlogN otherwise (where N is distance(first,last)).
185 */
186 template <typename _InputIterator>
187 multimap(_InputIterator __first, _InputIterator __last)
188 : _M_t(_Compare(), allocator_type())
189 { _M_t.insert_equal(__first, __last); }
190
191 /**
192 * @brief Builds a %multimap from a range.
193 * @param first An input iterator.
194 * @param last An input iterator.
195 * @param comp A comparison functor.
196 * @param a An allocator object.
197 *
198 * Create a %multimap consisting of copies of the elements from
199 * [first,last). This is linear in N if the range is already sorted,
200 * and NlogN otherwise (where N is distance(first,last)).
201 */
202 template <typename _InputIterator>
203 multimap(_InputIterator __first, _InputIterator __last,
204 const _Compare& __comp,
205 const allocator_type& __a = allocator_type())
206 : _M_t(__comp, __a)
207 { _M_t.insert_equal(__first, __last); }
208
209 // FIXME There is no dtor declared, but we should have something generated
210 // by Doxygen. I don't know what tags to add to this paragraph to make
211 // that happen:
212 /**
213 * The dtor only erases the elements, and note that if the elements
214 * themselves are pointers, the pointed-to memory is not touched in any
215 * way. Managing the pointer is the user's responsibilty.
216 */
217
218 /**
219 * @brief %Multimap assignment operator.
220 * @param x A %multimap of identical element and allocator types.
221 *
222 * All the elements of @a x are copied, but unlike the copy constructor,
223 * the allocator object is not copied.
224 */
225 multimap&
226 operator=(const multimap& __x)
227 {
228 _M_t = __x._M_t;
229 return *this;
230 }
231
232 /// Get a copy of the memory allocation object.
233 allocator_type
234 get_allocator() const { return _M_t.get_allocator(); }
235
236 // iterators
237 /**
238 * Returns a read/write iterator that points to the first pair in the
239 * %multimap. Iteration is done in ascending order according to the keys.
240 */
241 iterator
242 begin() { return _M_t.begin(); }
243
244 /**
245 * Returns a read-only (constant) iterator that points to the first pair
246 * in the %multimap. Iteration is done in ascending order according to the
247 * keys.
248 */
249 const_iterator
250 begin() const { return _M_t.begin(); }
251
252 /**
253 * Returns a read/write iterator that points one past the last pair in the
254 * %multimap. Iteration is done in ascending order according to the keys.
255 */
256 iterator
257 end() { return _M_t.end(); }
258
259 /**
260 * Returns a read-only (constant) iterator that points one past the last
261 * pair in the %multimap. Iteration is done in ascending order according
262 * to the keys.
263 */
264 const_iterator
265 end() const { return _M_t.end(); }
266
267 /**
268 * Returns a read/write reverse iterator that points to the last pair in
269 * the %multimap. Iteration is done in descending order according to the
270 * keys.
271 */
272 reverse_iterator
273 rbegin() { return _M_t.rbegin(); }
274
275 /**
276 * Returns a read-only (constant) reverse iterator that points to the last
277 * pair in the %multimap. Iteration is done in descending order according
278 * to the keys.
279 */
280 const_reverse_iterator
281 rbegin() const { return _M_t.rbegin(); }
282
283 /**
284 * Returns a read/write reverse iterator that points to one before the
285 * first pair in the %multimap. Iteration is done in descending order
286 * according to the keys.
287 */
288 reverse_iterator
289 rend() { return _M_t.rend(); }
290
291 /**
292 * Returns a read-only (constant) reverse iterator that points to one
293 * before the first pair in the %multimap. Iteration is done in descending
294 * order according to the keys.
295 */
296 const_reverse_iterator
297 rend() const { return _M_t.rend(); }
298
299 // capacity
300 /** Returns true if the %multimap is empty. */
301 bool
302 empty() const { return _M_t.empty(); }
303
304 /** Returns the size of the %multimap. */
305 size_type
306 size() const { return _M_t.size(); }
307
308 /** Returns the maximum size of the %multimap. */
309 size_type
310 max_size() const { return _M_t.max_size(); }
311
312 // modifiers
313 /**
314 * @brief Inserts a std::pair into the %multimap.
315 * @param x Pair to be inserted (see std::make_pair for easy creation of
316 * pairs).
317 * @return An iterator that points to the inserted (key,value) pair.
318 *
319 * This function inserts a (key, value) pair into the %multimap. Contrary
320 * to a std::map the %multimap does not rely on unique keys and thus
321 * multiple pairs with the same key can be inserted.
322 *
323 * Insertion requires logarithmic time.
324 */
325 iterator
326 insert(const value_type& __x) { return _M_t.insert_equal(__x); }
327
328 /**
329 * @brief Inserts a std::pair into the %multimap.
330 * @param position An iterator that serves as a hint as to where the
331 * pair should be inserted.
332 * @param x Pair to be inserted (see std::make_pair for easy creation of
333 * pairs).
334 * @return An iterator that points to the inserted (key,value) pair.
335 *
336 * This function inserts a (key, value) pair into the %multimap. Contrary
337 * to a std::map the %multimap does not rely on unique keys and thus
338 * multiple pairs with the same key can be inserted.
339 * Note that the first parameter is only a hint and can potentially
340 * improve the performance of the insertion process. A bad hint would
341 * cause no gains in efficiency.
342 *
343 * See http://gcc.gnu.org/onlinedocs/libstdc++/23_containers/howto.html#4
344 * for more on "hinting".
345 *
346 * Insertion requires logarithmic time (if the hint is not taken).
347 */
348 iterator
349 insert(iterator __position, const value_type& __x)
350 { return _M_t.insert_equal(__position, __x); }
351
352 /**
353 * @brief A template function that attemps to insert a range of elements.
354 * @param first Iterator pointing to the start of the range to be
355 * inserted.
356 * @param last Iterator pointing to the end of the range.
357 *
358 * Complexity similar to that of the range constructor.
359 */
360 template <typename _InputIterator>
361 void
362 insert(_InputIterator __first, _InputIterator __last)
363 { _M_t.insert_equal(__first, __last); }
364
365 /**
366 * @brief Erases an element from a %multimap.
367 * @param position An iterator pointing to the element to be erased.
368 *
369 * This function erases an element, pointed to by the given iterator, from
370 * a %multimap. Note that this function only erases the element, and that
371 * if the element is itself a pointer, the pointed-to memory is not
372 * touched in any way. Managing the pointer is the user's responsibilty.
373 */
374 void
375 erase(iterator __position) { _M_t.erase(__position); }
376
377 /**
378 * @brief Erases elements according to the provided key.
379 * @param x Key of element to be erased.
380 * @return The number of elements erased.
381 *
382 * This function erases all elements located by the given key from a
383 * %multimap.
384 * Note that this function only erases the element, and that if
385 * the element is itself a pointer, the pointed-to memory is not touched
386 * in any way. Managing the pointer is the user's responsibilty.
387 */
388 size_type
389 erase(const key_type& __x) { return _M_t.erase(__x); }
390
391 /**
392 * @brief Erases a [first,last) range of elements from a %multimap.
393 * @param first Iterator pointing to the start of the range to be erased.
394 * @param last Iterator pointing to the end of the range to be erased.
395 *
396 * This function erases a sequence of elements from a %multimap.
397 * Note that this function only erases the elements, and that if
398 * the elements themselves are pointers, the pointed-to memory is not
399 * touched in any way. Managing the pointer is the user's responsibilty.
400 */
401 void
402 erase(iterator __first, iterator __last) { _M_t.erase(__first, __last); }
403
404 /**
405 * @brief Swaps data with another %multimap.
406 * @param x A %multimap of the same element and allocator types.
407 *
408 * This exchanges the elements between two multimaps in constant time.
409 * (It is only swapping a pointer, an integer, and an instance of
410 * the @c Compare type (which itself is often stateless and empty), so it
411 * should be quite fast.)
412 * Note that the global std::swap() function is specialized such that
413 * std::swap(m1,m2) will feed to this function.
414 */
415 void
416 swap(multimap& __x) { _M_t.swap(__x._M_t); }
417
418 /**
419 * Erases all elements in a %multimap. Note that this function only erases
420 * the elements, and that if the elements themselves are pointers, the
421 * pointed-to memory is not touched in any way. Managing the pointer is
422 * the user's responsibilty.
423 */
424 void
425 clear() { _M_t.clear(); }
426
427 // observers
428 /**
429 * Returns the key comparison object out of which the %multimap
430 * was constructed.
431 */
432 key_compare
433 key_comp() const { return _M_t.key_comp(); }
434
435 /**
436 * Returns a value comparison object, built from the key comparison
437 * object out of which the %multimap was constructed.
438 */
439 value_compare
440 value_comp() const { return value_compare(_M_t.key_comp()); }
441
442 // multimap operations
443 /**
444 * @brief Tries to locate an element in a %multimap.
445 * @param x Key of (key, value) pair to be located.
446 * @return Iterator pointing to sought-after element,
447 * or end() if not found.
448 *
449 * This function takes a key and tries to locate the element with which
450 * the key matches. If successful the function returns an iterator
451 * pointing to the sought after %pair. If unsuccessful it returns the
452 * past-the-end ( @c end() ) iterator.
453 */
454 iterator
455 find(const key_type& __x) { return _M_t.find(__x); }
456
457 /**
458 * @brief Tries to locate an element in a %multimap.
459 * @param x Key of (key, value) pair to be located.
460 * @return Read-only (constant) iterator pointing to sought-after
461 * element, or end() if not found.
462 *
463 * This function takes a key and tries to locate the element with which
464 * the key matches. If successful the function returns a constant iterator
465 * pointing to the sought after %pair. If unsuccessful it returns the
466 * past-the-end ( @c end() ) iterator.
467 */
468 const_iterator
469 find(const key_type& __x) const { return _M_t.find(__x); }
470
471 /**
472 * @brief Finds the number of elements with given key.
473 * @param x Key of (key, value) pairs to be located.
474 * @return Number of elements with specified key.
475 */
476 size_type
477 count(const key_type& __x) const { return _M_t.count(__x); }
478
479 /**
480 * @brief Finds the beginning of a subsequence matching given key.
481 * @param x Key of (key, value) pair to be located.
482 * @return Iterator pointing to first element equal to or greater
483 * than key, or end().
484 *
485 * This function returns the first element of a subsequence of elements
486 * that matches the given key. If unsuccessful it returns an iterator
487 * pointing to the first element that has a greater value than given key
488 * or end() if no such element exists.
489 */
490 iterator
491 lower_bound(const key_type& __x) { return _M_t.lower_bound(__x); }
492
493 /**
494 * @brief Finds the beginning of a subsequence matching given key.
495 * @param x Key of (key, value) pair to be located.
496 * @return Read-only (constant) iterator pointing to first element
497 * equal to or greater than key, or end().
498 *
499 * This function returns the first element of a subsequence of elements
500 * that matches the given key. If unsuccessful the iterator will point
501 * to the next greatest element or, if no such greater element exists, to
502 * end().
503 */
504 const_iterator
505 lower_bound(const key_type& __x) const { return _M_t.lower_bound(__x); }
506
507 /**
508 * @brief Finds the end of a subsequence matching given key.
509 * @param x Key of (key, value) pair to be located.
510 * @return Iterator pointing to the first element
511 * greater than key, or end().
512 */
513 iterator
514 upper_bound(const key_type& __x) { return _M_t.upper_bound(__x); }
515
516 /**
517 * @brief Finds the end of a subsequence matching given key.
518 * @param x Key of (key, value) pair to be located.
519 * @return Read-only (constant) iterator pointing to first iterator
520 * greater than key, or end().
521 */
522 const_iterator
523 upper_bound(const key_type& __x) const { return _M_t.upper_bound(__x); }
524
525 /**
526 * @brief Finds a subsequence matching given key.
527 * @param x Key of (key, value) pairs to be located.
528 * @return Pair of iterators that possibly points to the subsequence
529 * matching given key.
530 *
531 * This function is equivalent to
532 * @code
533 * std::make_pair(c.lower_bound(val),
534 * c.upper_bound(val))
535 * @endcode
536 * (but is faster than making the calls separately).
537 */
538 pair<iterator,iterator>
539 equal_range(const key_type& __x) { return _M_t.equal_range(__x); }
540
541 /**
542 * @brief Finds a subsequence matching given key.
543 * @param x Key of (key, value) pairs to be located.
544 * @return Pair of read-only (constant) iterators that possibly points to
545 * the subsequence matching given key.
546 *
547 * This function is equivalent to
548 * @code
549 * std::make_pair(c.lower_bound(val),
550 * c.upper_bound(val))
551 * @endcode
552 * (but is faster than making the calls separately).
553 */
554 pair<const_iterator,const_iterator>
555 equal_range(const key_type& __x) const { return _M_t.equal_range(__x); }
556
557 template <typename _K1, typename _T1, typename _C1, typename _A1>
558 friend bool operator== (const multimap<_K1,_T1,_C1,_A1>&,
559 const multimap<_K1,_T1,_C1,_A1>&);
560 template <typename _K1, typename _T1, typename _C1, typename _A1>
561 friend bool operator< (const multimap<_K1,_T1,_C1,_A1>&,
562 const multimap<_K1,_T1,_C1,_A1>&);
563 };
564
565
566 /**
567 * @brief Multimap equality comparison.
568 * @param x A %multimap.
569 * @param y A %multimap of the same type as @a x.
570 * @return True iff the size and elements of the maps are equal.
571 *
572 * This is an equivalence relation. It is linear in the size of the
573 * multimaps. Multimaps are considered equivalent if their sizes are equal,
574 * and if corresponding elements compare equal.
575 */
576 template <typename _Key, typename _Tp, typename _Compare, typename _Alloc>
577 inline bool
578 operator==(const multimap<_Key,_Tp,_Compare,_Alloc>& __x,
579 const multimap<_Key,_Tp,_Compare,_Alloc>& __y)
580 {
581 return __x._M_t == __y._M_t;
582 }
583
584 /**
585 * @brief Multimap ordering relation.
586 * @param x A %multimap.
587 * @param y A %multimap of the same type as @a x.
588 * @return True iff @a x is lexicographically less than @a y.
589 *
590 * This is a total ordering relation. It is linear in the size of the
591 * multimaps. The elements must be comparable with @c <.
592 *
593 * See std::lexicographical_compare() for how the determination is made.
594 */
595 template <typename _Key, typename _Tp, typename _Compare, typename _Alloc>
596 inline bool
597 operator<(const multimap<_Key,_Tp,_Compare,_Alloc>& __x,
598 const multimap<_Key,_Tp,_Compare,_Alloc>& __y)
599 { return __x._M_t < __y._M_t; }
600
601 /// Based on operator==
602 template <typename _Key, typename _Tp, typename _Compare, typename _Alloc>
603 inline bool
604 operator!=(const multimap<_Key,_Tp,_Compare,_Alloc>& __x,
605 const multimap<_Key,_Tp,_Compare,_Alloc>& __y)
606 { return !(__x == __y); }
607
608 /// Based on operator<
609 template <typename _Key, typename _Tp, typename _Compare, typename _Alloc>
610 inline bool
611 operator>(const multimap<_Key,_Tp,_Compare,_Alloc>& __x,
612 const multimap<_Key,_Tp,_Compare,_Alloc>& __y)
613 { return __y < __x; }
614
615 /// Based on operator<
616 template <typename _Key, typename _Tp, typename _Compare, typename _Alloc>
617 inline bool
618 operator<=(const multimap<_Key,_Tp,_Compare,_Alloc>& __x,
619 const multimap<_Key,_Tp,_Compare,_Alloc>& __y)
620 { return !(__y < __x); }
621
622 /// Based on operator<
623 template <typename _Key, typename _Tp, typename _Compare, typename _Alloc>
624 inline bool
625 operator>=(const multimap<_Key,_Tp,_Compare,_Alloc>& __x,
626 const multimap<_Key,_Tp,_Compare,_Alloc>& __y)
627 { return !(__x < __y); }
628
629 /// See std::multimap::swap().
630 template <typename _Key, typename _Tp, typename _Compare, typename _Alloc>
631 inline void
632 swap(multimap<_Key,_Tp,_Compare,_Alloc>& __x,
633 multimap<_Key,_Tp,_Compare,_Alloc>& __y)
634 { __x.swap(__y); }
635 } // namespace std
636
637 #endif /* _MULTIMAP_H */