1// Map implementation -*- C++ -*-
2
3// Copyright (C) 2001-2014 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 3, 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// Under Section 7 of GPL version 3, you are granted additional
17// permissions described in the GCC Runtime Library Exception, version
18// 3.1, as published by the Free Software Foundation.
19
20// You should have received a copy of the GNU General Public License and
21// a copy of the GCC Runtime Library Exception along with this program;
22// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23// <http://www.gnu.org/licenses/>.
24
25/*
26 *
27 * Copyright (c) 1994
28 * Hewlett-Packard Company
29 *
30 * Permission to use, copy, modify, distribute and sell this software
31 * and its documentation for any purpose is hereby granted without fee,
32 * provided that the above copyright notice appear in all copies and
33 * that both that copyright notice and this permission notice appear
34 * in supporting documentation. Hewlett-Packard Company makes no
35 * representations about the suitability of this software for any
36 * purpose. It is provided "as is" without express or implied warranty.
37 *
38 *
39 * Copyright (c) 1996,1997
40 * Silicon Graphics Computer Systems, Inc.
41 *
42 * Permission to use, copy, modify, distribute and sell this software
43 * and its documentation for any purpose is hereby granted without fee,
44 * provided that the above copyright notice appear in all copies and
45 * that both that copyright notice and this permission notice appear
46 * in supporting documentation. Silicon Graphics makes no
47 * representations about the suitability of this software for any
48 * purpose. It is provided "as is" without express or implied warranty.
49 */
50
51/** @file bits/stl_map.h
52 * This is an internal header file, included by other library headers.
53 * Do not attempt to use it directly. @headername{map}
54 */
55
56#ifndef _STL_MAP_H
57#define _STL_MAP_H 1
58
59#include <bits/functexcept.h>
60#include <bits/concept_check.h>
61#if __cplusplus >= 201103L
62#include <initializer_list>
63#include <tuple>
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 * @tparam _Key Type of key objects.
77 * @tparam _Tp Type of mapped objects.
78 * @tparam _Compare Comparison function object type, defaults to less<_Key>.
79 * @tparam _Alloc Allocator type, defaults to
80 * allocator<pair<const _Key, _Tp>.
81 *
82 * Meets the requirements of a <a href="tables.html#65">container</a>, a
83 * <a href="tables.html#66">reversible container</a>, and an
84 * <a href="tables.html#69">associative container</a> (using unique keys).
85 * For a @c map<Key,T> the key_type is Key, the mapped_type is T, and the
86 * value_type is std::pair<const Key,T>.
87 *
88 * Maps support bidirectional iterators.
89 *
90 * The private tree data is declared exactly the same way for map and
91 * multimap; the distinction is made entirely in how the tree functions are
92 * called (*_unique versus *_equal, same as the standard).
93 */
94 template <typename _Key, typename _Tp, typename _Compare = std::less<_Key>,
95 typename _Alloc = std::allocator<std::pair<const _Key, _Tp> > >
96 class map
97 {
98 public:
99 typedef _Key key_type;
100 typedef _Tp mapped_type;
101 typedef std::pair<const _Key, _Tp> value_type;
102 typedef _Compare key_compare;
103 typedef _Alloc allocator_type;
104
105 private:
106 // concept requirements
107 typedef typename _Alloc::value_type _Alloc_value_type;
108 __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
109 __glibcxx_class_requires4(_Compare, bool, _Key, _Key,
110 _BinaryFunctionConcept)
111 __glibcxx_class_requires2(value_type, _Alloc_value_type, _SameTypeConcept)
112
113 public:
114 class value_compare
115 : public std::binary_function<value_type, value_type, bool>
116 {
117 friend class map<_Key, _Tp, _Compare, _Alloc>;
118 protected:
119 _Compare comp;
120
121 value_compare(_Compare __c)
122 : comp(__c) { }
123
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 /// This turns a red-black tree into a [multi]map.
131 typedef typename __gnu_cxx::__alloc_traits<_Alloc>::template
132 rebind<value_type>::other _Pair_alloc_type;
133
134 typedef _Rb_tree<key_type, value_type, _Select1st<value_type>,
135 key_compare, _Pair_alloc_type> _Rep_type;
136
137 /// The actual tree structure.
138 _Rep_type _M_t;
139
140 typedef __gnu_cxx::__alloc_traits<_Pair_alloc_type> _Alloc_traits;
141
142 public:
143 // many of these are specified differently in ISO, but the following are
144 // "functionally equivalent"
145 typedef typename _Alloc_traits::pointer pointer;
146 typedef typename _Alloc_traits::const_pointer const_pointer;
147 typedef typename _Alloc_traits::reference reference;
148 typedef typename _Alloc_traits::const_reference const_reference;
149 typedef typename _Rep_type::iterator iterator;
150 typedef typename _Rep_type::const_iterator const_iterator;
151 typedef typename _Rep_type::size_type size_type;
152 typedef typename _Rep_type::difference_type difference_type;
153 typedef typename _Rep_type::reverse_iterator reverse_iterator;
154 typedef typename _Rep_type::const_reverse_iterator const_reverse_iterator;
155
156 // [23.3.1.1] construct/copy/destroy
157 // (get_allocator() is also listed in this section)
158
159 /**
160 * @brief Default constructor creates no elements.
161 */
162 map()
163 : _M_t() { }
164
165 /**
166 * @brief Creates a %map with no elements.
167 * @param __comp A comparison object.
168 * @param __a An allocator object.
169 */
170 explicit
171 map(const _Compare& __comp,
172 const allocator_type& __a = allocator_type())
173 : _M_t(__comp, _Pair_alloc_type(__a)) { }
174
175 /**
176 * @brief %Map copy constructor.
177 * @param __x A %map of identical element and allocator types.
178 *
179 * The newly-created %map uses a copy of the allocation object
180 * used by @a __x.
181 */
182 map(const map& __x)
183 : _M_t(__x._M_t) { }
184
185#if __cplusplus >= 201103L
186 /**
187 * @brief %Map move constructor.
188 * @param __x A %map of identical element and allocator types.
189 *
190 * The newly-created %map contains the exact contents of @a __x.
191 * The contents of @a __x are a valid, but unspecified %map.
192 */
193 map(map&& __x)
194 noexcept(is_nothrow_copy_constructible<_Compare>::value)
195 : _M_t(std::move(__x._M_t)) { }
196
197 /**
198 * @brief Builds a %map from an initializer_list.
199 * @param __l An initializer_list.
200 * @param __comp A comparison object.
201 * @param __a An allocator object.
202 *
203 * Create a %map consisting of copies of the elements in the
204 * initializer_list @a __l.
205 * This is linear in N if the range is already sorted, and NlogN
206 * otherwise (where N is @a __l.size()).
207 */
208 map(initializer_list<value_type> __l,
209 const _Compare& __comp = _Compare(),
210 const allocator_type& __a = allocator_type())
211 : _M_t(__comp, _Pair_alloc_type(__a))
212 { _M_t._M_insert_unique(__l.begin(), __l.end()); }
213
214 /// Allocator-extended default constructor.
215 explicit
216 map(const allocator_type& __a)
217 : _M_t(_Compare(), _Pair_alloc_type(__a)) { }
218
219 /// Allocator-extended copy constructor.
220 map(const map& __m, const allocator_type& __a)
221 : _M_t(__m._M_t, _Pair_alloc_type(__a)) { }
222
223 /// Allocator-extended move constructor.
224 map(map&& __m, const allocator_type& __a)
225 noexcept(is_nothrow_copy_constructible<_Compare>::value
226 && _Alloc_traits::_S_always_equal())
227 : _M_t(std::move(__m._M_t), _Pair_alloc_type(__a)) { }
228
229 /// Allocator-extended initialier-list constructor.
230 map(initializer_list<value_type> __l, const allocator_type& __a)
231 : _M_t(_Compare(), _Pair_alloc_type(__a))
232 { _M_t._M_insert_unique(__l.begin(), __l.end()); }
233
234 /// Allocator-extended range constructor.
235 template<typename _InputIterator>
236 map(_InputIterator __first, _InputIterator __last,
237 const allocator_type& __a)
238 : _M_t(_Compare(), _Pair_alloc_type(__a))
239 { _M_t._M_insert_unique(__first, __last); }
240#endif
241
242 /**
243 * @brief Builds a %map from a range.
244 * @param __first An input iterator.
245 * @param __last An input iterator.
246 *
247 * Create a %map consisting of copies of the elements from
248 * [__first,__last). This is linear in N if the range is
249 * already sorted, and NlogN otherwise (where N is
250 * distance(__first,__last)).
251 */
252 template<typename _InputIterator>
253 map(_InputIterator __first, _InputIterator __last)
254 : _M_t()
255 { _M_t._M_insert_unique(__first, __last); }
256
257 /**
258 * @brief Builds a %map from a range.
259 * @param __first An input iterator.
260 * @param __last An input iterator.
261 * @param __comp A comparison functor.
262 * @param __a An allocator object.
263 *
264 * Create a %map consisting of copies of the elements from
265 * [__first,__last). This is linear in N if the range is
266 * already sorted, and NlogN otherwise (where N is
267 * distance(__first,__last)).
268 */
269 template<typename _InputIterator>
270 map(_InputIterator __first, _InputIterator __last,
271 const _Compare& __comp,
272 const allocator_type& __a = allocator_type())
273 : _M_t(__comp, _Pair_alloc_type(__a))
274 { _M_t._M_insert_unique(__first, __last); }
275
276 // FIXME There is no dtor declared, but we should have something
277 // generated by Doxygen. I don't know what tags to add to this
278 // paragraph to make that happen:
279 /**
280 * The dtor only erases the elements, and note that if the elements
281 * themselves are pointers, the pointed-to memory is not touched in any
282 * way. Managing the pointer is the user's responsibility.
283 */
284
285 /**
286 * @brief %Map assignment operator.
287 * @param __x A %map of identical element and allocator types.
288 *
289 * All the elements of @a __x are copied, but unlike the copy
290 * constructor, the allocator object is not copied.
291 */
292 map&
293 operator=(const map& __x)
294 {
295 _M_t = __x._M_t;
296 return *this;
297 }
298
299#if __cplusplus >= 201103L
300 /**
301 * @brief %Map move assignment operator.
302 * @param __x A %map of identical element and allocator types.
303 *
304 * The contents of @a __x are moved into this map (without copying
305 * if the allocators compare equal or get moved on assignment).
306 * Afterwards @a __x is in a valid, but unspecified state.
307 */
308 map&
309 operator=(map&& __x) noexcept(_Alloc_traits::_S_nothrow_move())
310 {
311 if (!_M_t._M_move_assign(__x._M_t))
312 {
313 // The rvalue's allocator cannot be moved and is not equal,
314 // so we need to individually move each element.
315 clear();
316 insert(std::__make_move_if_noexcept_iterator(__x.begin()),
317 std::__make_move_if_noexcept_iterator(__x.end()));
318 __x.clear();
319 }
320 return *this;
321 }
322
323 /**
324 * @brief %Map list assignment operator.
325 * @param __l An initializer_list.
326 *
327 * This function fills a %map with copies of the elements in the
328 * initializer list @a __l.
329 *
330 * Note that the assignment completely changes the %map and
331 * that the resulting %map's size is the same as the number
332 * of elements assigned. Old data may be lost.
333 */
334 map&
335 operator=(initializer_list<value_type> __l)
336 {
337 this->clear();
338 this->insert(__l.begin(), __l.end());
339 return *this;
340 }
341#endif
342
343 /// Get a copy of the memory allocation object.
344 allocator_type
345 get_allocator() const _GLIBCXX_NOEXCEPT
346 { return allocator_type(_M_t.get_allocator()); }
347
348 // iterators
349 /**
350 * Returns a read/write iterator that points to the first pair in the
351 * %map.
352 * Iteration is done in ascending order according to the keys.
353 */
354 iterator
355 begin() _GLIBCXX_NOEXCEPT
356 { return _M_t.begin(); }
357
358 /**
359 * Returns a read-only (constant) iterator that points to the first pair
360 * in the %map. Iteration is done in ascending order according to the
361 * keys.
362 */
363 const_iterator
364 begin() const _GLIBCXX_NOEXCEPT
365 { return _M_t.begin(); }
366
367 /**
368 * Returns a read/write iterator that points one past the last
369 * pair in the %map. Iteration is done in ascending order
370 * according to the keys.
371 */
372 iterator
373 end() _GLIBCXX_NOEXCEPT
374 { return _M_t.end(); }
375
376 /**
377 * Returns a read-only (constant) iterator that points one past the last
378 * pair in the %map. Iteration is done in ascending order according to
379 * the keys.
380 */
381 const_iterator
382 end() const _GLIBCXX_NOEXCEPT
383 { return _M_t.end(); }
384
385 /**
386 * Returns a read/write reverse iterator that points to the last pair in
387 * the %map. Iteration is done in descending order according to the
388 * keys.
389 */
390 reverse_iterator
391 rbegin() _GLIBCXX_NOEXCEPT
392 { return _M_t.rbegin(); }
393
394 /**
395 * Returns a read-only (constant) reverse iterator that points to the
396 * last pair in the %map. Iteration is done in descending order
397 * according to the keys.
398 */
399 const_reverse_iterator
400 rbegin() const _GLIBCXX_NOEXCEPT
401 { return _M_t.rbegin(); }
402
403 /**
404 * Returns a read/write reverse iterator that points to one before the
405 * first pair in the %map. Iteration is done in descending order
406 * according to the keys.
407 */
408 reverse_iterator
409 rend() _GLIBCXX_NOEXCEPT
410 { return _M_t.rend(); }
411
412 /**
413 * Returns a read-only (constant) reverse iterator that points to one
414 * before the first pair in the %map. Iteration is done in descending
415 * order according to the keys.
416 */
417 const_reverse_iterator
418 rend() const _GLIBCXX_NOEXCEPT
419 { return _M_t.rend(); }
420
421#if __cplusplus >= 201103L
422 /**
423 * Returns a read-only (constant) iterator that points to the first pair
424 * in the %map. Iteration is done in ascending order according to the
425 * keys.
426 */
427 const_iterator
428 cbegin() const noexcept
429 { return _M_t.begin(); }
430
431 /**
432 * Returns a read-only (constant) iterator that points one past the last
433 * pair in the %map. Iteration is done in ascending order according to
434 * the keys.
435 */
436 const_iterator
437 cend() const noexcept
438 { return _M_t.end(); }
439
440 /**
441 * Returns a read-only (constant) reverse iterator that points to the
442 * last pair in the %map. Iteration is done in descending order
443 * according to the keys.
444 */
445 const_reverse_iterator
446 crbegin() const noexcept
447 { return _M_t.rbegin(); }
448
449 /**
450 * Returns a read-only (constant) reverse iterator that points to one
451 * before the first pair in the %map. Iteration is done in descending
452 * order according to the keys.
453 */
454 const_reverse_iterator
455 crend() const noexcept
456 { return _M_t.rend(); }
457#endif
458
459 // capacity
460 /** Returns true if the %map is empty. (Thus begin() would equal
461 * end().)
462 */
463 bool
464 empty() const _GLIBCXX_NOEXCEPT
465 { return _M_t.empty(); }
466
467 /** Returns the size of the %map. */
468 size_type
469 size() const _GLIBCXX_NOEXCEPT
470 { return _M_t.size(); }
471
472 /** Returns the maximum size of the %map. */
473 size_type
474 max_size() const _GLIBCXX_NOEXCEPT
475 { return _M_t.max_size(); }
476
477 // [23.3.1.2] element access
478 /**
479 * @brief Subscript ( @c [] ) access to %map data.
480 * @param __k The key for which data should be retrieved.
481 * @return A reference to the data of the (key,data) %pair.
482 *
483 * Allows for easy lookup with the subscript ( @c [] )
484 * operator. Returns data associated with the key specified in
485 * subscript. If the key does not exist, a pair with that key
486 * is created using default values, which is then returned.
487 *
488 * Lookup requires logarithmic time.
489 */
490 mapped_type&
491 operator[](const key_type& __k)
492 {
493 // concept requirements
494 __glibcxx_function_requires(_DefaultConstructibleConcept<mapped_type>)
495
496 iterator __i = lower_bound(__k);
497 // __i->first is greater than or equivalent to __k.
498 if (__i == end() || key_comp()(__k, (*__i).first))
499#if __cplusplus >= 201103L
500 __i = _M_t._M_emplace_hint_unique(__i, std::piecewise_construct,
501 std::tuple<const key_type&>(__k),
502 std::tuple<>());
503#else
504 __i = insert(__i, value_type(__k, mapped_type()));
505#endif
506 return (*__i).second;
507 }
508
509#if __cplusplus >= 201103L
510 mapped_type&
511 operator[](key_type&& __k)
512 {
513 // concept requirements
514 __glibcxx_function_requires(_DefaultConstructibleConcept<mapped_type>)
515
516 iterator __i = lower_bound(__k);
517 // __i->first is greater than or equivalent to __k.
518 if (__i == end() || key_comp()(__k, (*__i).first))
519 __i = _M_t._M_emplace_hint_unique(__i, std::piecewise_construct,
520 std::forward_as_tuple(std::move(__k)),
521 std::tuple<>());
522 return (*__i).second;
523 }
524#endif
525
526 // _GLIBCXX_RESOLVE_LIB_DEFECTS
527 // DR 464. Suggestion for new member functions in standard containers.
528 /**
529 * @brief Access to %map data.
530 * @param __k The key for which data should be retrieved.
531 * @return A reference to the data whose key is equivalent to @a __k, if
532 * such a data is present in the %map.
533 * @throw std::out_of_range If no such data is present.
534 */
535 mapped_type&
536 at(const key_type& __k)
537 {
538 iterator __i = lower_bound(__k);
539 if (__i == end() || key_comp()(__k, (*__i).first))
540 __throw_out_of_range(__N("map::at"));
541 return (*__i).second;
542 }
543
544 const mapped_type&
545 at(const key_type& __k) const
546 {
547 const_iterator __i = lower_bound(__k);
548 if (__i == end() || key_comp()(__k, (*__i).first))
549 __throw_out_of_range(__N("map::at"));
550 return (*__i).second;
551 }
552
553 // modifiers
554#if __cplusplus >= 201103L
555 /**
556 * @brief Attempts to build and insert a std::pair into the %map.
557 *
558 * @param __args Arguments used to generate a new pair instance (see
559 * std::piecewise_contruct for passing arguments to each
560 * part of the pair constructor).
561 *
562 * @return A pair, of which the first element is an iterator that points
563 * to the possibly inserted pair, and the second is a bool that
564 * is true if the pair was actually inserted.
565 *
566 * This function attempts to build and insert a (key, value) %pair into
567 * the %map.
568 * A %map relies on unique keys and thus a %pair is only inserted if its
569 * first element (the key) is not already present in the %map.
570 *
571 * Insertion requires logarithmic time.
572 */
573 template<typename... _Args>
574 std::pair<iterator, bool>
575 emplace(_Args&&... __args)
576 { return _M_t._M_emplace_unique(std::forward<_Args>(__args)...); }
577
578 /**
579 * @brief Attempts to build and insert a std::pair into the %map.
580 *
581 * @param __pos An iterator that serves as a hint as to where the pair
582 * should be inserted.
583 * @param __args Arguments used to generate a new pair instance (see
584 * std::piecewise_contruct for passing arguments to each
585 * part of the pair constructor).
586 * @return An iterator that points to the element with key of the
587 * std::pair built from @a __args (may or may not be that
588 * std::pair).
589 *
590 * This function is not concerned about whether the insertion took place,
591 * and thus does not return a boolean like the single-argument emplace()
592 * does.
593 * Note that the first parameter is only a hint and can potentially
594 * improve the performance of the insertion process. A bad hint would
595 * cause no gains in efficiency.
596 *
597 * See
598 * http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt07ch17.html
599 * for more on @a hinting.
600 *
601 * Insertion requires logarithmic time (if the hint is not taken).
602 */
603 template<typename... _Args>
604 iterator
605 emplace_hint(const_iterator __pos, _Args&&... __args)
606 {
607 return _M_t._M_emplace_hint_unique(__pos,
608 std::forward<_Args>(__args)...);
609 }
610#endif
611
612 /**
613 * @brief Attempts to insert a std::pair into the %map.
614
615 * @param __x Pair to be inserted (see std::make_pair for easy
616 * creation of pairs).
617 *
618 * @return A pair, of which the first element is an iterator that
619 * points to the possibly inserted pair, and the second is
620 * a bool that is true if the pair was actually inserted.
621 *
622 * This function attempts to insert a (key, value) %pair into the %map.
623 * A %map relies on unique keys and thus a %pair is only inserted if its
624 * first element (the key) is not already present in the %map.
625 *
626 * Insertion requires logarithmic time.
627 */
628 std::pair<iterator, bool>
629 insert(const value_type& __x)
630 { return _M_t._M_insert_unique(__x); }
631
632#if __cplusplus >= 201103L
633 template<typename _Pair, typename = typename
634 std::enable_if<std::is_constructible<value_type,
635 _Pair&&>::value>::type>
636 std::pair<iterator, bool>
637 insert(_Pair&& __x)
638 { return _M_t._M_insert_unique(std::forward<_Pair>(__x)); }
639#endif
640
641#if __cplusplus >= 201103L
642 /**
643 * @brief Attempts to insert a list of std::pairs into the %map.
644 * @param __list A std::initializer_list<value_type> of pairs to be
645 * inserted.
646 *
647 * Complexity similar to that of the range constructor.
648 */
649 void
650 insert(std::initializer_list<value_type> __list)
651 { insert(__list.begin(), __list.end()); }
652#endif
653
654 /**
655 * @brief Attempts to insert a std::pair into the %map.
656 * @param __position An iterator that serves as a hint as to where the
657 * pair should be inserted.
658 * @param __x Pair to be inserted (see std::make_pair for easy creation
659 * of pairs).
660 * @return An iterator that points to the element with key of
661 * @a __x (may or may not be the %pair passed in).
662 *
663
664 * This function is not concerned about whether the insertion
665 * took place, and thus does not return a boolean like the
666 * single-argument insert() does. Note that the first
667 * parameter is only a hint and can potentially improve the
668 * performance of the insertion process. A bad hint would
669 * cause no gains in efficiency.
670 *
671 * See
672 * http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt07ch17.html
673 * for more on @a hinting.
674 *
675 * Insertion requires logarithmic time (if the hint is not taken).
676 */
677 iterator
678#if __cplusplus >= 201103L
679 insert(const_iterator __position, const value_type& __x)
680#else
681 insert(iterator __position, const value_type& __x)
682#endif
683 { return _M_t._M_insert_unique_(__position, __x); }
684
685#if __cplusplus >= 201103L
686 template<typename _Pair, typename = typename
687 std::enable_if<std::is_constructible<value_type,
688 _Pair&&>::value>::type>
689 iterator
690 insert(const_iterator __position, _Pair&& __x)
691 { return _M_t._M_insert_unique_(__position,
692 std::forward<_Pair>(__x)); }
693#endif
694
695 /**
696 * @brief Template function that attempts to insert a range of elements.
697 * @param __first Iterator pointing to the start of the range to be
698 * inserted.
699 * @param __last Iterator pointing to the end of the range.
700 *
701 * Complexity similar to that of the range constructor.
702 */
703 template<typename _InputIterator>
704 void
705 insert(_InputIterator __first, _InputIterator __last)
706 { _M_t._M_insert_unique(__first, __last); }
707
708#if __cplusplus >= 201103L
709 // _GLIBCXX_RESOLVE_LIB_DEFECTS
710 // DR 130. Associative erase should return an iterator.
711 /**
712 * @brief Erases an element from a %map.
713 * @param __position An iterator pointing to the element to be erased.
714 * @return An iterator pointing to the element immediately following
715 * @a position prior to the element being erased. If no such
716 * element exists, end() is returned.
717 *
718 * This function erases an element, pointed to by the given
719 * iterator, from a %map. Note that this function only erases
720 * the element, and that if the element is itself a pointer,
721 * the pointed-to memory is not touched in any way. Managing
722 * the pointer is the user's responsibility.
723 */
724 iterator
725 erase(const_iterator __position)
726 { return _M_t.erase(__position); }
727
728 // LWG 2059
729 _GLIBCXX_ABI_TAG_CXX11
730 iterator
731 erase(iterator __position)
732 { return _M_t.erase(__position); }
733#else
734 /**
735 * @brief Erases an element from a %map.
736 * @param __position An iterator pointing to the element to be erased.
737 *
738 * This function erases an element, pointed to by the given
739 * iterator, from a %map. Note that this function only erases
740 * the element, and that if the element is itself a pointer,
741 * the pointed-to memory is not touched in any way. Managing
742 * the pointer is the user's responsibility.
743 */
744 void
745 erase(iterator __position)
746 { _M_t.erase(__position); }
747#endif
748
749 /**
750 * @brief Erases elements according to the provided key.
751 * @param __x Key of element to be erased.
752 * @return The number of elements erased.
753 *
754 * This function erases all the elements located by the given key from
755 * a %map.
756 * Note that this function only erases the element, and that if
757 * the element is itself a pointer, the pointed-to memory is not touched
758 * in any way. Managing the pointer is the user's responsibility.
759 */
760 size_type
761 erase(const key_type& __x)
762 { return _M_t.erase(__x); }
763
764#if __cplusplus >= 201103L
765 // _GLIBCXX_RESOLVE_LIB_DEFECTS
766 // DR 130. Associative erase should return an iterator.
767 /**
768 * @brief Erases a [first,last) range of elements from a %map.
769 * @param __first Iterator pointing to the start of the range to be
770 * erased.
771 * @param __last Iterator pointing to the end of the range to
772 * be erased.
773 * @return The iterator @a __last.
774 *
775 * This function erases a sequence of elements from a %map.
776 * Note that this function only erases the element, and that if
777 * the element is itself a pointer, the pointed-to memory is not touched
778 * in any way. Managing the pointer is the user's responsibility.
779 */
780 iterator
781 erase(const_iterator __first, const_iterator __last)
782 { return _M_t.erase(__first, __last); }
783#else
784 /**
785 * @brief Erases a [__first,__last) range of elements from a %map.
786 * @param __first Iterator pointing to the start of the range to be
787 * erased.
788 * @param __last Iterator pointing to the end of the range to
789 * be erased.
790 *
791 * This function erases a sequence of elements from a %map.
792 * Note that this function only erases the element, and that if
793 * the element is itself a pointer, the pointed-to memory is not touched
794 * in any way. Managing the pointer is the user's responsibility.
795 */
796 void
797 erase(iterator __first, iterator __last)
798 { _M_t.erase(__first, __last); }
799#endif
800
801 /**
802 * @brief Swaps data with another %map.
803 * @param __x A %map of the same element and allocator types.
804 *
805 * This exchanges the elements between two maps in constant
806 * time. (It is only swapping a pointer, an integer, and an
807 * instance of the @c Compare type (which itself is often
808 * stateless and empty), so it should be quite fast.) Note
809 * that the global std::swap() function is specialized such
810 * that std::swap(m1,m2) will feed to this function.
811 */
812 void
813 swap(map& __x)
814#if __cplusplus >= 201103L
815 noexcept(_Alloc_traits::_S_nothrow_swap())
816#endif
817 { _M_t.swap(__x._M_t); }
818
819 /**
820 * Erases all elements in a %map. Note that this function only
821 * erases the elements, and that if the elements themselves are
822 * pointers, the pointed-to memory is not touched in any way.
823 * Managing the pointer is the user's responsibility.
824 */
825 void
826 clear() _GLIBCXX_NOEXCEPT
827 { _M_t.clear(); }
828
829 // observers
830 /**
831 * Returns the key comparison object out of which the %map was
832 * constructed.
833 */
834 key_compare
835 key_comp() const
836 { return _M_t.key_comp(); }
837
838 /**
839 * Returns a value comparison object, built from the key comparison
840 * object out of which the %map was constructed.
841 */
842 value_compare
843 value_comp() const
844 { return value_compare(_M_t.key_comp()); }
845
846 // [23.3.1.3] map operations
847 /**
848 * @brief Tries to locate an element in a %map.
849 * @param __x Key of (key, value) %pair to be located.
850 * @return Iterator pointing to sought-after element, or end() if not
851 * found.
852 *
853 * This function takes a key and tries to locate the element with which
854 * the key matches. If successful the function returns an iterator
855 * pointing to the sought after %pair. If unsuccessful it returns the
856 * past-the-end ( @c end() ) iterator.
857 */
858 iterator
859 find(const key_type& __x)
860 { return _M_t.find(__x); }
861
862 /**
863 * @brief Tries to locate an element in a %map.
864 * @param __x Key of (key, value) %pair to be located.
865 * @return Read-only (constant) iterator pointing to sought-after
866 * element, or end() if not found.
867 *
868 * This function takes a key and tries to locate the element with which
869 * the key matches. If successful the function returns a constant
870 * iterator pointing to the sought after %pair. If unsuccessful it
871 * returns the past-the-end ( @c end() ) iterator.
872 */
873 const_iterator
874 find(const key_type& __x) const
875 { return _M_t.find(__x); }
876
877 /**
878 * @brief Finds the number of elements with given key.
879 * @param __x Key of (key, value) pairs to be located.
880 * @return Number of elements with specified key.
881 *
882 * This function only makes sense for multimaps; for map the result will
883 * either be 0 (not present) or 1 (present).
884 */
885 size_type
886 count(const key_type& __x) const
887 { return _M_t.find(__x) == _M_t.end() ? 0 : 1; }
888
889 /**
890 * @brief Finds the beginning of a subsequence matching given key.
891 * @param __x Key of (key, value) pair to be located.
892 * @return Iterator pointing to first element equal to or greater
893 * than key, or end().
894 *
895 * This function returns the first element of a subsequence of elements
896 * that matches the given key. If unsuccessful it returns an iterator
897 * pointing to the first element that has a greater value than given key
898 * or end() if no such element exists.
899 */
900 iterator
901 lower_bound(const key_type& __x)
902 { return _M_t.lower_bound(__x); }
903
904 /**
905 * @brief Finds the beginning of a subsequence matching given key.
906 * @param __x Key of (key, value) pair to be located.
907 * @return Read-only (constant) iterator pointing to first element
908 * equal to or greater than key, or end().
909 *
910 * This function returns the first element of a subsequence of elements
911 * that matches the given key. If unsuccessful it returns an iterator
912 * pointing to the first element that has a greater value than given key
913 * or end() if no such element exists.
914 */
915 const_iterator
916 lower_bound(const key_type& __x) const
917 { return _M_t.lower_bound(__x); }
918
919 /**
920 * @brief Finds the end of a subsequence matching given key.
921 * @param __x Key of (key, value) pair to be located.
922 * @return Iterator pointing to the first element
923 * greater than key, or end().
924 */
925 iterator
926 upper_bound(const key_type& __x)
927 { return _M_t.upper_bound(__x); }
928
929 /**
930 * @brief Finds the end of a subsequence matching given key.
931 * @param __x Key of (key, value) pair to be located.
932 * @return Read-only (constant) iterator pointing to first iterator
933 * greater than key, or end().
934 */
935 const_iterator
936 upper_bound(const key_type& __x) const
937 { return _M_t.upper_bound(__x); }
938
939 /**
940 * @brief Finds a subsequence matching given key.
941 * @param __x Key of (key, value) pairs to be located.
942 * @return Pair of iterators that possibly points to the subsequence
943 * matching given key.
944 *
945 * This function is equivalent to
946 * @code
947 * std::make_pair(c.lower_bound(val),
948 * c.upper_bound(val))
949 * @endcode
950 * (but is faster than making the calls separately).
951 *
952 * This function probably only makes sense for multimaps.
953 */
954 std::pair<iterator, iterator>
955 equal_range(const key_type& __x)
956 { return _M_t.equal_range(__x); }
957
958 /**
959 * @brief Finds a subsequence matching given key.
960 * @param __x Key of (key, value) pairs to be located.
961 * @return Pair of read-only (constant) iterators that possibly points
962 * to the subsequence matching given key.
963 *
964 * This function is equivalent to
965 * @code
966 * std::make_pair(c.lower_bound(val),
967 * c.upper_bound(val))
968 * @endcode
969 * (but is faster than making the calls separately).
970 *
971 * This function probably only makes sense for multimaps.
972 */
973 std::pair<const_iterator, const_iterator>
974 equal_range(const key_type& __x) const
975 { return _M_t.equal_range(__x); }
976
977 template<typename _K1, typename _T1, typename _C1, typename _A1>
978 friend bool
979 operator==(const map<_K1, _T1, _C1, _A1>&,
980 const map<_K1, _T1, _C1, _A1>&);
981
982 template<typename _K1, typename _T1, typename _C1, typename _A1>
983 friend bool
984 operator<(const map<_K1, _T1, _C1, _A1>&,
985 const map<_K1, _T1, _C1, _A1>&);
986 };
987
988 /**
989 * @brief Map equality comparison.
990 * @param __x A %map.
991 * @param __y A %map of the same type as @a x.
992 * @return True iff the size and elements of the maps are equal.
993 *
994 * This is an equivalence relation. It is linear in the size of the
995 * maps. Maps are considered equivalent if their sizes are equal,
996 * and if corresponding elements compare equal.
997 */
998 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
999 inline bool
1000 operator==(const map<_Key, _Tp, _Compare, _Alloc>& __x,
1001 const map<_Key, _Tp, _Compare, _Alloc>& __y)
1002 { return __x._M_t == __y._M_t; }
1003
1004 /**
1005 * @brief Map ordering relation.
1006 * @param __x A %map.
1007 * @param __y A %map of the same type as @a x.
1008 * @return True iff @a x is lexicographically less than @a y.
1009 *
1010 * This is a total ordering relation. It is linear in the size of the
1011 * maps. The elements must be comparable with @c <.
1012 *
1013 * See std::lexicographical_compare() for how the determination is made.
1014 */
1015 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
1016 inline bool
1017 operator<(const map<_Key, _Tp, _Compare, _Alloc>& __x,
1018 const map<_Key, _Tp, _Compare, _Alloc>& __y)
1019 { return __x._M_t < __y._M_t; }
1020
1021 /// Based on operator==
1022 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
1023 inline bool
1024 operator!=(const map<_Key, _Tp, _Compare, _Alloc>& __x,
1025 const map<_Key, _Tp, _Compare, _Alloc>& __y)
1026 { return !(__x == __y); }
1027
1028 /// Based on operator<
1029 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
1030 inline bool
1031 operator>(const map<_Key, _Tp, _Compare, _Alloc>& __x,
1032 const map<_Key, _Tp, _Compare, _Alloc>& __y)
1033 { return __y < __x; }
1034
1035 /// Based on operator<
1036 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
1037 inline bool
1038 operator<=(const map<_Key, _Tp, _Compare, _Alloc>& __x,
1039 const map<_Key, _Tp, _Compare, _Alloc>& __y)
1040 { return !(__y < __x); }
1041
1042 /// Based on operator<
1043 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
1044 inline bool
1045 operator>=(const map<_Key, _Tp, _Compare, _Alloc>& __x,
1046 const map<_Key, _Tp, _Compare, _Alloc>& __y)
1047 { return !(__x < __y); }
1048
1049 /// See std::map::swap().
1050 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
1051 inline void
1052 swap(map<_Key, _Tp, _Compare, _Alloc>& __x,
1053 map<_Key, _Tp, _Compare, _Alloc>& __y)
1054 { __x.swap(__y); }
1055
1056_GLIBCXX_END_NAMESPACE_CONTAINER
1057} // namespace std
1058
1059#endif /* _STL_MAP_H */
1060