1// Map implementation -*- C++ -*-
2
3// Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
4// 2011, 2012 Free Software Foundation, Inc.
5//
6// This file is part of the GNU ISO C++ Library. This library is free
7// software; you can redistribute it and/or modify it under the
8// terms of the GNU General Public License as published by the
9// Free Software Foundation; either version 3, or (at your option)
10// any later version.
11
12// This library is distributed in the hope that it will be useful,
13// but WITHOUT ANY WARRANTY; without even the implied warranty of
14// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15// GNU General Public License for more details.
16
17// Under Section 7 of GPL version 3, you are granted additional
18// permissions described in the GCC Runtime Library Exception, version
19// 3.1, as published by the Free Software Foundation.
20
21// You should have received a copy of the GNU General Public License and
22// a copy of the GCC Runtime Library Exception along with this program;
23// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
24// <http://www.gnu.org/licenses/>.
25
26/*
27 *
28 * Copyright (c) 1994
29 * Hewlett-Packard Company
30 *
31 * Permission to use, copy, modify, distribute and sell this software
32 * and its documentation for any purpose is hereby granted without fee,
33 * provided that the above copyright notice appear in all copies and
34 * that both that copyright notice and this permission notice appear
35 * in supporting documentation. Hewlett-Packard Company makes no
36 * representations about the suitability of this software for any
37 * purpose. It is provided "as is" without express or implied warranty.
38 *
39 *
40 * Copyright (c) 1996,1997
41 * Silicon Graphics Computer Systems, Inc.
42 *
43 * Permission to use, copy, modify, distribute and sell this software
44 * and its documentation for any purpose is hereby granted without fee,
45 * provided that the above copyright notice appear in all copies and
46 * that both that copyright notice and this permission notice appear
47 * in supporting documentation. Silicon Graphics makes no
48 * representations about the suitability of this software for any
49 * purpose. It is provided "as is" without express or implied warranty.
50 */
51
52/** @file bits/stl_map.h
53 * This is an internal header file, included by other library headers.
54 * Do not attempt to use it directly. @headername{map}
55 */
56
57#ifndef _STL_MAP_H
58#define _STL_MAP_H 1
59
60#include <bits/functexcept.h>
61#include <bits/concept_check.h>
62#ifdef __GXX_EXPERIMENTAL_CXX0X__
63#include <initializer_list>
64#endif
65
66namespace std _GLIBCXX_VISIBILITY(default)
67{
68_GLIBCXX_BEGIN_NAMESPACE_CONTAINER
69
70 /**
71 * @brief A standard container made up of (key,value) pairs, which can be
72 * retrieved based on a key, in logarithmic time.
73 *
74 * @ingroup associative_containers
75 *
76 * Meets the requirements of a <a href="tables.html#65">container</a>, a
77 * <a href="tables.html#66">reversible container</a>, and an
78 * <a href="tables.html#69">associative container</a> (using unique keys).
79 * For a @c map<Key,T> the key_type is Key, the mapped_type is T, and the
80 * value_type is std::pair<const Key,T>.
81 *
82 * Maps support bidirectional iterators.
83 *
84 * The private tree data is declared exactly the same way for map and
85 * multimap; the distinction is made entirely in how the tree functions are
86 * called (*_unique versus *_equal, same as the standard).
87 */
88 template <typename _Key, typename _Tp, typename _Compare = std::less<_Key>,
89 typename _Alloc = std::allocator<std::pair<const _Key, _Tp> > >
90 class map
91 {
92 public:
93 typedef _Key key_type;
94 typedef _Tp mapped_type;
95 typedef std::pair<const _Key, _Tp> value_type;
96 typedef _Compare key_compare;
97 typedef _Alloc allocator_type;
98
99 private:
100 // concept requirements
101 typedef typename _Alloc::value_type _Alloc_value_type;
102 __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
103 __glibcxx_class_requires4(_Compare, bool, _Key, _Key,
104 _BinaryFunctionConcept)
105 __glibcxx_class_requires2(value_type, _Alloc_value_type, _SameTypeConcept)
106
107 public:
108 class value_compare
109 : public std::binary_function<value_type, value_type, bool>
110 {
111 friend class map<_Key, _Tp, _Compare, _Alloc>;
112 protected:
113 _Compare comp;
114
115 value_compare(_Compare __c)
116 : comp(__c) { }
117
118 public:
119 bool operator()(const value_type& __x, const value_type& __y) const
120 { return comp(__x.first, __y.first); }
121 };
122
123 private:
124 /// This turns a red-black tree into a [multi]map.
125 typedef typename _Alloc::template rebind<value_type>::other
126 _Pair_alloc_type;
127
128 typedef _Rb_tree<key_type, value_type, _Select1st<value_type>,
129 key_compare, _Pair_alloc_type> _Rep_type;
130
131 /// The actual tree structure.
132 _Rep_type _M_t;
133
134 public:
135 // many of these are specified differently in ISO, but the following are
136 // "functionally equivalent"
137 typedef typename _Pair_alloc_type::pointer pointer;
138 typedef typename _Pair_alloc_type::const_pointer const_pointer;
139 typedef typename _Pair_alloc_type::reference reference;
140 typedef typename _Pair_alloc_type::const_reference const_reference;
141 typedef typename _Rep_type::iterator iterator;
142 typedef typename _Rep_type::const_iterator const_iterator;
143 typedef typename _Rep_type::size_type size_type;
144 typedef typename _Rep_type::difference_type difference_type;
145 typedef typename _Rep_type::reverse_iterator reverse_iterator;
146 typedef typename _Rep_type::const_reverse_iterator const_reverse_iterator;
147
148 // [23.3.1.1] construct/copy/destroy
149 // (get_allocator() is normally listed in this section, but seems to have
150 // been accidentally omitted in the printed standard)
151 /**
152 * @brief Default constructor creates no elements.
153 */
154 map()
155 : _M_t() { }
156
157 /**
158 * @brief Creates a %map with no elements.
159 * @param __comp A comparison object.
160 * @param __a An allocator object.
161 */
162 explicit
163 map(const _Compare& __comp,
164 const allocator_type& __a = allocator_type())
165 : _M_t(__comp, _Pair_alloc_type(__a)) { }
166
167 /**
168 * @brief %Map copy constructor.
169 * @param __x A %map of identical element and allocator types.
170 *
171 * The newly-created %map uses a copy of the allocation object
172 * used by @a __x.
173 */
174 map(const map& __x)
175 : _M_t(__x._M_t) { }
176
177#ifdef __GXX_EXPERIMENTAL_CXX0X__
178 /**
179 * @brief %Map move constructor.
180 * @param __x A %map of identical element and allocator types.
181 *
182 * The newly-created %map contains the exact contents of @a __x.
183 * The contents of @a __x are a valid, but unspecified %map.
184 */
185 map(map&& __x)
186 noexcept(is_nothrow_copy_constructible<_Compare>::value)
187 : _M_t(std::move(__x._M_t)) { }
188
189 /**
190 * @brief Builds a %map from an initializer_list.
191 * @param __l An initializer_list.
192 * @param __comp A comparison object.
193 * @param __a An allocator object.
194 *
195 * Create a %map consisting of copies of the elements in the
196 * initializer_list @a __l.
197 * This is linear in N if the range is already sorted, and NlogN
198 * otherwise (where N is @a __l.size()).
199 */
200 map(initializer_list<value_type> __l,
201 const _Compare& __comp = _Compare(),
202 const allocator_type& __a = allocator_type())
203 : _M_t(__comp, _Pair_alloc_type(__a))
204 { _M_t._M_insert_unique(__l.begin(), __l.end()); }
205#endif
206
207 /**
208 * @brief Builds a %map from a range.
209 * @param __first An input iterator.
210 * @param __last An input iterator.
211 *
212 * Create a %map consisting of copies of the elements from
213 * [__first,__last). This is linear in N if the range is
214 * already sorted, and NlogN otherwise (where N is
215 * distance(__first,__last)).
216 */
217 template<typename _InputIterator>
218 map(_InputIterator __first, _InputIterator __last)
219 : _M_t()
220 { _M_t._M_insert_unique(__first, __last); }
221
222 /**
223 * @brief Builds a %map from a range.
224 * @param __first An input iterator.
225 * @param __last An input iterator.
226 * @param __comp A comparison functor.
227 * @param __a An allocator object.
228 *
229 * Create a %map consisting of copies of the elements from
230 * [__first,__last). This is linear in N if the range is
231 * already sorted, and NlogN otherwise (where N is
232 * distance(__first,__last)).
233 */
234 template<typename _InputIterator>
235 map(_InputIterator __first, _InputIterator __last,
236 const _Compare& __comp,
237 const allocator_type& __a = allocator_type())
238 : _M_t(__comp, _Pair_alloc_type(__a))
239 { _M_t._M_insert_unique(__first, __last); }
240
241 // FIXME There is no dtor declared, but we should have something
242 // generated by Doxygen. I don't know what tags to add to this
243 // paragraph to make that happen:
244 /**
245 * The dtor only erases the elements, and note that if the elements
246 * themselves are pointers, the pointed-to memory is not touched in any
247 * way. Managing the pointer is the user's responsibility.
248 */
249
250 /**
251 * @brief %Map assignment operator.
252 * @param __x A %map of identical element and allocator types.
253 *
254 * All the elements of @a __x are copied, but unlike the copy
255 * constructor, the allocator object is not copied.
256 */
257 map&
258 operator=(const map& __x)
259 {
260 _M_t = __x._M_t;
261 return *this;
262 }
263
264#ifdef __GXX_EXPERIMENTAL_CXX0X__
265 /**
266 * @brief %Map move assignment operator.
267 * @param __x A %map of identical element and allocator types.
268 *
269 * The contents of @a __x are moved into this map (without copying).
270 * @a __x is a valid, but unspecified %map.
271 */
272 map&
273 operator=(map&& __x)
274 {
275 // NB: DR 1204.
276 // NB: DR 675.
277 this->clear();
278 this->swap(__x);
279 return *this;
280 }
281
282 /**
283 * @brief %Map list assignment operator.
284 * @param __l An initializer_list.
285 *
286 * This function fills a %map with copies of the elements in the
287 * initializer list @a __l.
288 *
289 * Note that the assignment completely changes the %map and
290 * that the resulting %map's size is the same as the number
291 * of elements assigned. Old data may be lost.
292 */
293 map&
294 operator=(initializer_list<value_type> __l)
295 {
296 this->clear();
297 this->insert(__l.begin(), __l.end());
298 return *this;
299 }
300#endif
301
302 /// Get a copy of the memory allocation object.
303 allocator_type
304 get_allocator() const _GLIBCXX_NOEXCEPT
305 { return allocator_type(_M_t.get_allocator()); }
306
307 // iterators
308 /**
309 * Returns a read/write iterator that points to the first pair in the
310 * %map.
311 * Iteration is done in ascending order according to the keys.
312 */
313 iterator
314 begin() _GLIBCXX_NOEXCEPT
315 { return _M_t.begin(); }
316
317 /**
318 * Returns a read-only (constant) iterator that points to the first pair
319 * in the %map. Iteration is done in ascending order according to the
320 * keys.
321 */
322 const_iterator
323 begin() const _GLIBCXX_NOEXCEPT
324 { return _M_t.begin(); }
325
326 /**
327 * Returns a read/write iterator that points one past the last
328 * pair in the %map. Iteration is done in ascending order
329 * according to the keys.
330 */
331 iterator
332 end() _GLIBCXX_NOEXCEPT
333 { return _M_t.end(); }
334
335 /**
336 * Returns a read-only (constant) iterator that points one past the last
337 * pair in the %map. Iteration is done in ascending order according to
338 * the keys.
339 */
340 const_iterator
341 end() const _GLIBCXX_NOEXCEPT
342 { return _M_t.end(); }
343
344 /**
345 * Returns a read/write reverse iterator that points to the last pair in
346 * the %map. Iteration is done in descending order according to the
347 * keys.
348 */
349 reverse_iterator
350 rbegin() _GLIBCXX_NOEXCEPT
351 { return _M_t.rbegin(); }
352
353 /**
354 * Returns a read-only (constant) reverse iterator that points to the
355 * last pair in the %map. Iteration is done in descending order
356 * according to the keys.
357 */
358 const_reverse_iterator
359 rbegin() const _GLIBCXX_NOEXCEPT
360 { return _M_t.rbegin(); }
361
362 /**
363 * Returns a read/write reverse iterator that points to one before the
364 * first pair in the %map. Iteration is done in descending order
365 * according to the keys.
366 */
367 reverse_iterator
368 rend() _GLIBCXX_NOEXCEPT
369 { return _M_t.rend(); }
370
371 /**
372 * Returns a read-only (constant) reverse iterator that points to one
373 * before the first pair in the %map. Iteration is done in descending
374 * order according to the keys.
375 */
376 const_reverse_iterator
377 rend() const _GLIBCXX_NOEXCEPT
378 { return _M_t.rend(); }
379
380#ifdef __GXX_EXPERIMENTAL_CXX0X__
381 /**
382 * Returns a read-only (constant) iterator that points to the first pair
383 * in the %map. Iteration is done in ascending order according to the
384 * keys.
385 */
386 const_iterator
387 cbegin() const noexcept
388 { return _M_t.begin(); }
389
390 /**
391 * Returns a read-only (constant) iterator that points one past the last
392 * pair in the %map. Iteration is done in ascending order according to
393 * the keys.
394 */
395 const_iterator
396 cend() const noexcept
397 { return _M_t.end(); }
398
399 /**
400 * Returns a read-only (constant) reverse iterator that points to the
401 * last pair in the %map. Iteration is done in descending order
402 * according to the keys.
403 */
404 const_reverse_iterator
405 crbegin() const noexcept
406 { return _M_t.rbegin(); }
407
408 /**
409 * Returns a read-only (constant) reverse iterator that points to one
410 * before the first pair in the %map. Iteration is done in descending
411 * order according to the keys.
412 */
413 const_reverse_iterator
414 crend() const noexcept
415 { return _M_t.rend(); }
416#endif
417
418 // capacity
419 /** Returns true if the %map is empty. (Thus begin() would equal
420 * end().)
421 */
422 bool
423 empty() const _GLIBCXX_NOEXCEPT
424 { return _M_t.empty(); }
425
426 /** Returns the size of the %map. */
427 size_type
428 size() const _GLIBCXX_NOEXCEPT
429 { return _M_t.size(); }
430
431 /** Returns the maximum size of the %map. */
432 size_type
433 max_size() const _GLIBCXX_NOEXCEPT
434 { return _M_t.max_size(); }
435
436 // [23.3.1.2] element access
437 /**
438 * @brief Subscript ( @c [] ) access to %map data.
439 * @param __k The key for which data should be retrieved.
440 * @return A reference to the data of the (key,data) %pair.
441 *
442 * Allows for easy lookup with the subscript ( @c [] )
443 * operator. Returns data associated with the key specified in
444 * subscript. If the key does not exist, a pair with that key
445 * is created using default values, which is then returned.
446 *
447 * Lookup requires logarithmic time.
448 */
449 mapped_type&
450 operator[](const key_type& __k)
451 {
452 // concept requirements
453 __glibcxx_function_requires(_DefaultConstructibleConcept<mapped_type>)
454
455 iterator __i = lower_bound(__k);
456 // __i->first is greater than or equivalent to __k.
457 if (__i == end() || key_comp()(__k, (*__i).first))
458 __i = insert(__i, value_type(__k, mapped_type()));
459 return (*__i).second;
460 }
461
462#ifdef __GXX_EXPERIMENTAL_CXX0X__
463 mapped_type&
464 operator[](key_type&& __k)
465 {
466 // concept requirements
467 __glibcxx_function_requires(_DefaultConstructibleConcept<mapped_type>)
468
469 iterator __i = lower_bound(__k);
470 // __i->first is greater than or equivalent to __k.
471 if (__i == end() || key_comp()(__k, (*__i).first))
472 __i = insert(__i, std::make_pair(std::move(__k), mapped_type()));
473 return (*__i).second;
474 }
475#endif
476
477 // _GLIBCXX_RESOLVE_LIB_DEFECTS
478 // DR 464. Suggestion for new member functions in standard containers.
479 /**
480 * @brief Access to %map data.
481 * @param __k The key for which data should be retrieved.
482 * @return A reference to the data whose key is equivalent to @a __k, if
483 * such a data is present in the %map.
484 * @throw std::out_of_range If no such data is present.
485 */
486 mapped_type&
487 at(const key_type& __k)
488 {
489 iterator __i = lower_bound(__k);
490 if (__i == end() || key_comp()(__k, (*__i).first))
491 __throw_out_of_range(__N("map::at"));
492 return (*__i).second;
493 }
494
495 const mapped_type&
496 at(const key_type& __k) const
497 {
498 const_iterator __i = lower_bound(__k);
499 if (__i == end() || key_comp()(__k, (*__i).first))
500 __throw_out_of_range(__N("map::at"));
501 return (*__i).second;
502 }
503
504 // modifiers
505 /**
506 * @brief Attempts to insert a std::pair into the %map.
507
508 * @param __x Pair to be inserted (see std::make_pair for easy
509 * creation of pairs).
510 *
511 * @return A pair, of which the first element is an iterator that
512 * points to the possibly inserted pair, and the second is
513 * a bool that is true if the pair was actually inserted.
514 *
515 * This function attempts to insert a (key, value) %pair into the %map.
516 * A %map relies on unique keys and thus a %pair is only inserted if its
517 * first element (the key) is not already present in the %map.
518 *
519 * Insertion requires logarithmic time.
520 */
521 std::pair<iterator, bool>
522 insert(const value_type& __x)
523 { return _M_t._M_insert_unique(__x); }
524
525#ifdef __GXX_EXPERIMENTAL_CXX0X__
526 template<typename _Pair, typename = typename
527 std::enable_if<std::is_constructible<value_type,
528 _Pair&&>::value>::type>
529 std::pair<iterator, bool>
530 insert(_Pair&& __x)
531 { return _M_t._M_insert_unique(std::forward<_Pair>(__x)); }
532#endif
533
534#ifdef __GXX_EXPERIMENTAL_CXX0X__
535 /**
536 * @brief Attempts to insert a list of std::pairs into the %map.
537 * @param __list A std::initializer_list<value_type> of pairs to be
538 * inserted.
539 *
540 * Complexity similar to that of the range constructor.
541 */
542 void
543 insert(std::initializer_list<value_type> __list)
544 { insert(__list.begin(), __list.end()); }
545#endif
546
547 /**
548 * @brief Attempts to insert a std::pair into the %map.
549 * @param __position An iterator that serves as a hint as to where the
550 * pair should be inserted.
551 * @param __x Pair to be inserted (see std::make_pair for easy creation
552 * of pairs).
553 * @return An iterator that points to the element with key of
554 * @a __x (may or may not be the %pair passed in).
555 *
556
557 * This function is not concerned about whether the insertion
558 * took place, and thus does not return a boolean like the
559 * single-argument insert() does. Note that the first
560 * parameter is only a hint and can potentially improve the
561 * performance of the insertion process. A bad hint would
562 * cause no gains in efficiency.
563 *
564 * See
565 * http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt07ch17.html
566 * for more on @a hinting.
567 *
568 * Insertion requires logarithmic time (if the hint is not taken).
569 */
570 iterator
571#ifdef __GXX_EXPERIMENTAL_CXX0X__
572 insert(const_iterator __position, const value_type& __x)
573#else
574 insert(iterator __position, const value_type& __x)
575#endif
576 { return _M_t._M_insert_unique_(__position, __x); }
577
578#ifdef __GXX_EXPERIMENTAL_CXX0X__
579 template<typename _Pair, typename = typename
580 std::enable_if<std::is_constructible<value_type,
581 _Pair&&>::value>::type>
582 iterator
583 insert(const_iterator __position, _Pair&& __x)
584 { return _M_t._M_insert_unique_(__position,
585 std::forward<_Pair>(__x)); }
586#endif
587
588 /**
589 * @brief Template function that attempts to insert a range of elements.
590 * @param __first Iterator pointing to the start of the range to be
591 * inserted.
592 * @param __last Iterator pointing to the end of the range.
593 *
594 * Complexity similar to that of the range constructor.
595 */
596 template<typename _InputIterator>
597 void
598 insert(_InputIterator __first, _InputIterator __last)
599 { _M_t._M_insert_unique(__first, __last); }
600
601#ifdef __GXX_EXPERIMENTAL_CXX0X__
602 // _GLIBCXX_RESOLVE_LIB_DEFECTS
603 // DR 130. Associative erase should return an iterator.
604 /**
605 * @brief Erases an element from a %map.
606 * @param __position An iterator pointing to the element to be erased.
607 * @return An iterator pointing to the element immediately following
608 * @a position prior to the element being erased. If no such
609 * element exists, end() is returned.
610 *
611 * This function erases an element, pointed to by the given
612 * iterator, from a %map. Note that this function only erases
613 * the element, and that if the element is itself a pointer,
614 * the pointed-to memory is not touched in any way. Managing
615 * the pointer is the user's responsibility.
616 */
617 iterator
618 erase(const_iterator __position)
619 { return _M_t.erase(__position); }
620
621 // LWG 2059.
622 iterator
623 erase(iterator __position)
624 { return _M_t.erase(__position); }
625#else
626 /**
627 * @brief Erases an element from a %map.
628 * @param __position An iterator pointing to the element to be erased.
629 *
630 * This function erases an element, pointed to by the given
631 * iterator, from a %map. Note that this function only erases
632 * the element, and that if the element is itself a pointer,
633 * the pointed-to memory is not touched in any way. Managing
634 * the pointer is the user's responsibility.
635 */
636 void
637 erase(iterator __position)
638 { _M_t.erase(__position); }
639#endif
640
641 /**
642 * @brief Erases elements according to the provided key.
643 * @param __x Key of element to be erased.
644 * @return The number of elements erased.
645 *
646 * This function erases all the elements located by the given key from
647 * a %map.
648 * Note that this function only erases the element, and that if
649 * the element is itself a pointer, the pointed-to memory is not touched
650 * in any way. Managing the pointer is the user's responsibility.
651 */
652 size_type
653 erase(const key_type& __x)
654 { return _M_t.erase(__x); }
655
656#ifdef __GXX_EXPERIMENTAL_CXX0X__
657 // _GLIBCXX_RESOLVE_LIB_DEFECTS
658 // DR 130. Associative erase should return an iterator.
659 /**
660 * @brief Erases a [first,last) range of elements from a %map.
661 * @param __first Iterator pointing to the start of the range to be
662 * erased.
663 * @param __last Iterator pointing to the end of the range to
664 * be erased.
665 * @return The iterator @a __last.
666 *
667 * This function erases a sequence of elements from a %map.
668 * Note that this function only erases the element, and that if
669 * the element is itself a pointer, the pointed-to memory is not touched
670 * in any way. Managing the pointer is the user's responsibility.
671 */
672 iterator
673 erase(const_iterator __first, const_iterator __last)
674 { return _M_t.erase(__first, __last); }
675#else
676 /**
677 * @brief Erases a [__first,__last) range of elements from a %map.
678 * @param __first Iterator pointing to the start of the range to be
679 * erased.
680 * @param __last Iterator pointing to the end of the range to
681 * be erased.
682 *
683 * This function erases a sequence of elements from a %map.
684 * Note that this function only erases the element, and that if
685 * the element is itself a pointer, the pointed-to memory is not touched
686 * in any way. Managing the pointer is the user's responsibility.
687 */
688 void
689 erase(iterator __first, iterator __last)
690 { _M_t.erase(__first, __last); }
691#endif
692
693 /**
694 * @brief Swaps data with another %map.
695 * @param __x A %map of the same element and allocator types.
696 *
697 * This exchanges the elements between two maps in constant
698 * time. (It is only swapping a pointer, an integer, and an
699 * instance of the @c Compare type (which itself is often
700 * stateless and empty), so it should be quite fast.) Note
701 * that the global std::swap() function is specialized such
702 * that std::swap(m1,m2) will feed to this function.
703 */
704 void
705 swap(map& __x)
706 { _M_t.swap(__x._M_t); }
707
708 /**
709 * Erases all elements in a %map. Note that this function only
710 * erases the elements, and that if the elements themselves are
711 * pointers, the pointed-to memory is not touched in any way.
712 * Managing the pointer is the user's responsibility.
713 */
714 void
715 clear() _GLIBCXX_NOEXCEPT
716 { _M_t.clear(); }
717
718 // observers
719 /**
720 * Returns the key comparison object out of which the %map was
721 * constructed.
722 */
723 key_compare
724 key_comp() const
725 { return _M_t.key_comp(); }
726
727 /**
728 * Returns a value comparison object, built from the key comparison
729 * object out of which the %map was constructed.
730 */
731 value_compare
732 value_comp() const
733 { return value_compare(_M_t.key_comp()); }
734
735 // [23.3.1.3] map operations
736 /**
737 * @brief Tries to locate an element in a %map.
738 * @param __x Key of (key, value) %pair to be located.
739 * @return Iterator pointing to sought-after element, or end() if not
740 * found.
741 *
742 * This function takes a key and tries to locate the element with which
743 * the key matches. If successful the function returns an iterator
744 * pointing to the sought after %pair. If unsuccessful it returns the
745 * past-the-end ( @c end() ) iterator.
746 */
747 iterator
748 find(const key_type& __x)
749 { return _M_t.find(__x); }
750
751 /**
752 * @brief Tries to locate an element in a %map.
753 * @param __x Key of (key, value) %pair to be located.
754 * @return Read-only (constant) iterator pointing to sought-after
755 * element, or end() if not found.
756 *
757 * This function takes a key and tries to locate the element with which
758 * the key matches. If successful the function returns a constant
759 * iterator pointing to the sought after %pair. If unsuccessful it
760 * returns the past-the-end ( @c end() ) iterator.
761 */
762 const_iterator
763 find(const key_type& __x) const
764 { return _M_t.find(__x); }
765
766 /**
767 * @brief Finds the number of elements with given key.
768 * @param __x Key of (key, value) pairs to be located.
769 * @return Number of elements with specified key.
770 *
771 * This function only makes sense for multimaps; for map the result will
772 * either be 0 (not present) or 1 (present).
773 */
774 size_type
775 count(const key_type& __x) const
776 { return _M_t.find(__x) == _M_t.end() ? 0 : 1; }
777
778 /**
779 * @brief Finds the beginning of a subsequence matching given key.
780 * @param __x Key of (key, value) pair to be located.
781 * @return Iterator pointing to first element equal to or greater
782 * than key, or end().
783 *
784 * This function returns the first element of a subsequence of elements
785 * that matches the given key. If unsuccessful it returns an iterator
786 * pointing to the first element that has a greater value than given key
787 * or end() if no such element exists.
788 */
789 iterator
790 lower_bound(const key_type& __x)
791 { return _M_t.lower_bound(__x); }
792
793 /**
794 * @brief Finds the beginning of a subsequence matching given key.
795 * @param __x Key of (key, value) pair to be located.
796 * @return Read-only (constant) iterator pointing to first element
797 * equal to or greater than key, or end().
798 *
799 * This function returns the first element of a subsequence of elements
800 * that matches the given key. If unsuccessful it returns an iterator
801 * pointing to the first element that has a greater value than given key
802 * or end() if no such element exists.
803 */
804 const_iterator
805 lower_bound(const key_type& __x) const
806 { return _M_t.lower_bound(__x); }
807
808 /**
809 * @brief Finds the end of a subsequence matching given key.
810 * @param __x Key of (key, value) pair to be located.
811 * @return Iterator pointing to the first element
812 * greater than key, or end().
813 */
814 iterator
815 upper_bound(const key_type& __x)
816 { return _M_t.upper_bound(__x); }
817
818 /**
819 * @brief Finds the end of a subsequence matching given key.
820 * @param __x Key of (key, value) pair to be located.
821 * @return Read-only (constant) iterator pointing to first iterator
822 * greater than key, or end().
823 */
824 const_iterator
825 upper_bound(const key_type& __x) const
826 { return _M_t.upper_bound(__x); }
827
828 /**
829 * @brief Finds a subsequence matching given key.
830 * @param __x Key of (key, value) pairs to be located.
831 * @return Pair of iterators that possibly points to the subsequence
832 * matching given key.
833 *
834 * This function is equivalent to
835 * @code
836 * std::make_pair(c.lower_bound(val),
837 * c.upper_bound(val))
838 * @endcode
839 * (but is faster than making the calls separately).
840 *
841 * This function probably only makes sense for multimaps.
842 */
843 std::pair<iterator, iterator>
844 equal_range(const key_type& __x)
845 { return _M_t.equal_range(__x); }
846
847 /**
848 * @brief Finds a subsequence matching given key.
849 * @param __x Key of (key, value) pairs to be located.
850 * @return Pair of read-only (constant) iterators that possibly points
851 * to the subsequence matching given key.
852 *
853 * This function is equivalent to
854 * @code
855 * std::make_pair(c.lower_bound(val),
856 * c.upper_bound(val))
857 * @endcode
858 * (but is faster than making the calls separately).
859 *
860 * This function probably only makes sense for multimaps.
861 */
862 std::pair<const_iterator, const_iterator>
863 equal_range(const key_type& __x) const
864 { return _M_t.equal_range(__x); }
865
866 template<typename _K1, typename _T1, typename _C1, typename _A1>
867 friend bool
868 operator==(const map<_K1, _T1, _C1, _A1>&,
869 const map<_K1, _T1, _C1, _A1>&);
870
871 template<typename _K1, typename _T1, typename _C1, typename _A1>
872 friend bool
873 operator<(const map<_K1, _T1, _C1, _A1>&,
874 const map<_K1, _T1, _C1, _A1>&);
875 };
876
877 /**
878 * @brief Map equality comparison.
879 * @param __x A %map.
880 * @param __y A %map of the same type as @a x.
881 * @return True iff the size and elements of the maps are equal.
882 *
883 * This is an equivalence relation. It is linear in the size of the
884 * maps. Maps are considered equivalent if their sizes are equal,
885 * and if corresponding elements compare equal.
886 */
887 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
888 inline bool
889 operator==(const map<_Key, _Tp, _Compare, _Alloc>& __x,
890 const map<_Key, _Tp, _Compare, _Alloc>& __y)
891 { return __x._M_t == __y._M_t; }
892
893 /**
894 * @brief Map ordering relation.
895 * @param __x A %map.
896 * @param __y A %map of the same type as @a x.
897 * @return True iff @a x is lexicographically less than @a y.
898 *
899 * This is a total ordering relation. It is linear in the size of the
900 * maps. The elements must be comparable with @c <.
901 *
902 * See std::lexicographical_compare() for how the determination is made.
903 */
904 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
905 inline bool
906 operator<(const map<_Key, _Tp, _Compare, _Alloc>& __x,
907 const map<_Key, _Tp, _Compare, _Alloc>& __y)
908 { return __x._M_t < __y._M_t; }
909
910 /// Based on operator==
911 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
912 inline bool
913 operator!=(const map<_Key, _Tp, _Compare, _Alloc>& __x,
914 const map<_Key, _Tp, _Compare, _Alloc>& __y)
915 { return !(__x == __y); }
916
917 /// Based on operator<
918 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
919 inline bool
920 operator>(const map<_Key, _Tp, _Compare, _Alloc>& __x,
921 const map<_Key, _Tp, _Compare, _Alloc>& __y)
922 { return __y < __x; }
923
924 /// Based on operator<
925 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
926 inline bool
927 operator<=(const map<_Key, _Tp, _Compare, _Alloc>& __x,
928 const map<_Key, _Tp, _Compare, _Alloc>& __y)
929 { return !(__y < __x); }
930
931 /// Based on operator<
932 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
933 inline bool
934 operator>=(const map<_Key, _Tp, _Compare, _Alloc>& __x,
935 const map<_Key, _Tp, _Compare, _Alloc>& __y)
936 { return !(__x < __y); }
937
938 /// See std::map::swap().
939 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
940 inline void
941 swap(map<_Key, _Tp, _Compare, _Alloc>& __x,
942 map<_Key, _Tp, _Compare, _Alloc>& __y)
943 { __x.swap(__y); }
944
945_GLIBCXX_END_NAMESPACE_CONTAINER
946} // namespace std
947
948#endif /* _STL_MAP_H */
949