1// Map implementation -*- C++ -*-
2
3// Copyright (C) 2001-2021 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_VERSION
69_GLIBCXX_BEGIN_NAMESPACE_CONTAINER
70
71 template <typename _Key, typename _Tp, typename _Compare, typename _Alloc>
72 class multimap;
73
74 /**
75 * @brief A standard container made up of (key,value) pairs, which can be
76 * retrieved based on a key, in logarithmic time.
77 *
78 * @ingroup associative_containers
79 *
80 * @tparam _Key Type of key objects.
81 * @tparam _Tp Type of mapped objects.
82 * @tparam _Compare Comparison function object type, defaults to less<_Key>.
83 * @tparam _Alloc Allocator type, defaults to
84 * allocator<pair<const _Key, _Tp>.
85 *
86 * Meets the requirements of a <a href="tables.html#65">container</a>, a
87 * <a href="tables.html#66">reversible container</a>, and an
88 * <a href="tables.html#69">associative container</a> (using unique keys).
89 * For a @c map<Key,T> the key_type is Key, the mapped_type is T, and the
90 * value_type is std::pair<const Key,T>.
91 *
92 * Maps support bidirectional iterators.
93 *
94 * The private tree data is declared exactly the same way for map and
95 * multimap; the distinction is made entirely in how the tree functions are
96 * called (*_unique versus *_equal, same as the standard).
97 */
98 template <typename _Key, typename _Tp, typename _Compare = std::less<_Key>,
99 typename _Alloc = std::allocator<std::pair<const _Key, _Tp> > >
100 class map
101 {
102 public:
103 typedef _Key key_type;
104 typedef _Tp mapped_type;
105 typedef std::pair<const _Key, _Tp> value_type;
106 typedef _Compare key_compare;
107 typedef _Alloc allocator_type;
108
109 private:
110#ifdef _GLIBCXX_CONCEPT_CHECKS
111 // concept requirements
112 typedef typename _Alloc::value_type _Alloc_value_type;
113# if __cplusplus < 201103L
114 __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
115# endif
116 __glibcxx_class_requires4(_Compare, bool, _Key, _Key,
117 _BinaryFunctionConcept)
118 __glibcxx_class_requires2(value_type, _Alloc_value_type, _SameTypeConcept)
119#endif
120
121#if __cplusplus >= 201103L
122#if __cplusplus > 201703L || defined __STRICT_ANSI__
123 static_assert(is_same<typename _Alloc::value_type, value_type>::value,
124 "std::map must have the same value_type as its allocator");
125#endif
126#endif
127
128 public:
129 class value_compare
130 : public std::binary_function<value_type, value_type, bool>
131 {
132 friend class map<_Key, _Tp, _Compare, _Alloc>;
133 protected:
134 _Compare comp;
135
136 value_compare(_Compare __c)
137 : comp(__c) { }
138
139 public:
140 bool operator()(const value_type& __x, const value_type& __y) const
141 { return comp(__x.first, __y.first); }
142 };
143
144 private:
145 /// This turns a red-black tree into a [multi]map.
146 typedef typename __gnu_cxx::__alloc_traits<_Alloc>::template
147 rebind<value_type>::other _Pair_alloc_type;
148
149 typedef _Rb_tree<key_type, value_type, _Select1st<value_type>,
150 key_compare, _Pair_alloc_type> _Rep_type;
151
152 /// The actual tree structure.
153 _Rep_type _M_t;
154
155 typedef __gnu_cxx::__alloc_traits<_Pair_alloc_type> _Alloc_traits;
156
157 public:
158 // many of these are specified differently in ISO, but the following are
159 // "functionally equivalent"
160 typedef typename _Alloc_traits::pointer pointer;
161 typedef typename _Alloc_traits::const_pointer const_pointer;
162 typedef typename _Alloc_traits::reference reference;
163 typedef typename _Alloc_traits::const_reference const_reference;
164 typedef typename _Rep_type::iterator iterator;
165 typedef typename _Rep_type::const_iterator const_iterator;
166 typedef typename _Rep_type::size_type size_type;
167 typedef typename _Rep_type::difference_type difference_type;
168 typedef typename _Rep_type::reverse_iterator reverse_iterator;
169 typedef typename _Rep_type::const_reverse_iterator const_reverse_iterator;
170
171#if __cplusplus > 201402L
172 using node_type = typename _Rep_type::node_type;
173 using insert_return_type = typename _Rep_type::insert_return_type;
174#endif
175
176 // [23.3.1.1] construct/copy/destroy
177 // (get_allocator() is also listed in this section)
178
179 /**
180 * @brief Default constructor creates no elements.
181 */
182#if __cplusplus < 201103L
183 map() : _M_t() { }
184#else
185 map() = default;
186#endif
187
188 /**
189 * @brief Creates a %map with no elements.
190 * @param __comp A comparison object.
191 * @param __a An allocator object.
192 */
193 explicit
194 map(const _Compare& __comp,
195 const allocator_type& __a = allocator_type())
196 : _M_t(__comp, _Pair_alloc_type(__a)) { }
197
198 /**
199 * @brief %Map copy constructor.
200 *
201 * Whether the allocator is copied depends on the allocator traits.
202 */
203#if __cplusplus < 201103L
204 map(const map& __x)
205 : _M_t(__x._M_t) { }
206#else
207 map(const map&) = default;
208
209 /**
210 * @brief %Map move constructor.
211 *
212 * The newly-created %map contains the exact contents of the moved
213 * instance. The moved instance is a valid, but unspecified, %map.
214 */
215 map(map&&) = default;
216
217 /**
218 * @brief Builds a %map from an initializer_list.
219 * @param __l An initializer_list.
220 * @param __comp A comparison object.
221 * @param __a An allocator object.
222 *
223 * Create a %map consisting of copies of the elements in the
224 * initializer_list @a __l.
225 * This is linear in N if the range is already sorted, and NlogN
226 * otherwise (where N is @a __l.size()).
227 */
228 map(initializer_list<value_type> __l,
229 const _Compare& __comp = _Compare(),
230 const allocator_type& __a = allocator_type())
231 : _M_t(__comp, _Pair_alloc_type(__a))
232 { _M_t._M_insert_range_unique(__l.begin(), __l.end()); }
233
234 /// Allocator-extended default constructor.
235 explicit
236 map(const allocator_type& __a)
237 : _M_t(_Pair_alloc_type(__a)) { }
238
239 /// Allocator-extended copy constructor.
240 map(const map& __m, const allocator_type& __a)
241 : _M_t(__m._M_t, _Pair_alloc_type(__a)) { }
242
243 /// Allocator-extended move constructor.
244 map(map&& __m, const allocator_type& __a)
245 noexcept(is_nothrow_copy_constructible<_Compare>::value
246 && _Alloc_traits::_S_always_equal())
247 : _M_t(std::move(__m._M_t), _Pair_alloc_type(__a)) { }
248
249 /// Allocator-extended initialier-list constructor.
250 map(initializer_list<value_type> __l, const allocator_type& __a)
251 : _M_t(_Pair_alloc_type(__a))
252 { _M_t._M_insert_range_unique(__l.begin(), __l.end()); }
253
254 /// Allocator-extended range constructor.
255 template<typename _InputIterator>
256 map(_InputIterator __first, _InputIterator __last,
257 const allocator_type& __a)
258 : _M_t(_Pair_alloc_type(__a))
259 { _M_t._M_insert_range_unique(__first, __last); }
260#endif
261
262 /**
263 * @brief Builds a %map from a range.
264 * @param __first An input iterator.
265 * @param __last An input iterator.
266 *
267 * Create a %map consisting of copies of the elements from
268 * [__first,__last). This is linear in N if the range is
269 * already sorted, and NlogN otherwise (where N is
270 * distance(__first,__last)).
271 */
272 template<typename _InputIterator>
273 map(_InputIterator __first, _InputIterator __last)
274 : _M_t()
275 { _M_t._M_insert_range_unique(__first, __last); }
276
277 /**
278 * @brief Builds a %map from a range.
279 * @param __first An input iterator.
280 * @param __last An input iterator.
281 * @param __comp A comparison functor.
282 * @param __a An allocator object.
283 *
284 * Create a %map consisting of copies of the elements from
285 * [__first,__last). This is linear in N if the range is
286 * already sorted, and NlogN otherwise (where N is
287 * distance(__first,__last)).
288 */
289 template<typename _InputIterator>
290 map(_InputIterator __first, _InputIterator __last,
291 const _Compare& __comp,
292 const allocator_type& __a = allocator_type())
293 : _M_t(__comp, _Pair_alloc_type(__a))
294 { _M_t._M_insert_range_unique(__first, __last); }
295
296#if __cplusplus >= 201103L
297 /**
298 * The dtor only erases the elements, and note that if the elements
299 * themselves are pointers, the pointed-to memory is not touched in any
300 * way. Managing the pointer is the user's responsibility.
301 */
302 ~map() = default;
303#endif
304
305 /**
306 * @brief %Map assignment operator.
307 *
308 * Whether the allocator is copied depends on the allocator traits.
309 */
310#if __cplusplus < 201103L
311 map&
312 operator=(const map& __x)
313 {
314 _M_t = __x._M_t;
315 return *this;
316 }
317#else
318 map&
319 operator=(const map&) = default;
320
321 /// Move assignment operator.
322 map&
323 operator=(map&&) = default;
324
325 /**
326 * @brief %Map list assignment operator.
327 * @param __l An initializer_list.
328 *
329 * This function fills a %map with copies of the elements in the
330 * initializer list @a __l.
331 *
332 * Note that the assignment completely changes the %map and
333 * that the resulting %map's size is the same as the number
334 * of elements assigned.
335 */
336 map&
337 operator=(initializer_list<value_type> __l)
338 {
339 _M_t._M_assign_unique(__l.begin(), __l.end());
340 return *this;
341 }
342#endif
343
344 /// Get a copy of the memory allocation object.
345 allocator_type
346 get_allocator() const _GLIBCXX_NOEXCEPT
347 { return allocator_type(_M_t.get_allocator()); }
348
349 // iterators
350 /**
351 * Returns a read/write iterator that points to the first pair in the
352 * %map.
353 * Iteration is done in ascending order according to the keys.
354 */
355 iterator
356 begin() _GLIBCXX_NOEXCEPT
357 { return _M_t.begin(); }
358
359 /**
360 * Returns a read-only (constant) iterator that points to the first pair
361 * in the %map. Iteration is done in ascending order according to the
362 * keys.
363 */
364 const_iterator
365 begin() const _GLIBCXX_NOEXCEPT
366 { return _M_t.begin(); }
367
368 /**
369 * Returns a read/write iterator that points one past the last
370 * pair in the %map. Iteration is done in ascending order
371 * according to the keys.
372 */
373 iterator
374 end() _GLIBCXX_NOEXCEPT
375 { return _M_t.end(); }
376
377 /**
378 * Returns a read-only (constant) iterator that points one past the last
379 * pair in the %map. Iteration is done in ascending order according to
380 * the keys.
381 */
382 const_iterator
383 end() const _GLIBCXX_NOEXCEPT
384 { return _M_t.end(); }
385
386 /**
387 * Returns a read/write reverse iterator that points to the last pair in
388 * the %map. Iteration is done in descending order according to the
389 * keys.
390 */
391 reverse_iterator
392 rbegin() _GLIBCXX_NOEXCEPT
393 { return _M_t.rbegin(); }
394
395 /**
396 * Returns a read-only (constant) reverse iterator that points to the
397 * last pair in the %map. Iteration is done in descending order
398 * according to the keys.
399 */
400 const_reverse_iterator
401 rbegin() const _GLIBCXX_NOEXCEPT
402 { return _M_t.rbegin(); }
403
404 /**
405 * Returns a read/write reverse iterator that points to one before the
406 * first pair in the %map. Iteration is done in descending order
407 * according to the keys.
408 */
409 reverse_iterator
410 rend() _GLIBCXX_NOEXCEPT
411 { return _M_t.rend(); }
412
413 /**
414 * Returns a read-only (constant) reverse iterator that points to one
415 * before the first pair in the %map. Iteration is done in descending
416 * order according to the keys.
417 */
418 const_reverse_iterator
419 rend() const _GLIBCXX_NOEXCEPT
420 { return _M_t.rend(); }
421
422#if __cplusplus >= 201103L
423 /**
424 * Returns a read-only (constant) iterator that points to the first pair
425 * in the %map. Iteration is done in ascending order according to the
426 * keys.
427 */
428 const_iterator
429 cbegin() const noexcept
430 { return _M_t.begin(); }
431
432 /**
433 * Returns a read-only (constant) iterator that points one past the last
434 * pair in the %map. Iteration is done in ascending order according to
435 * the keys.
436 */
437 const_iterator
438 cend() const noexcept
439 { return _M_t.end(); }
440
441 /**
442 * Returns a read-only (constant) reverse iterator that points to the
443 * last pair in the %map. Iteration is done in descending order
444 * according to the keys.
445 */
446 const_reverse_iterator
447 crbegin() const noexcept
448 { return _M_t.rbegin(); }
449
450 /**
451 * Returns a read-only (constant) reverse iterator that points to one
452 * before the first pair in the %map. Iteration is done in descending
453 * order according to the keys.
454 */
455 const_reverse_iterator
456 crend() const noexcept
457 { return _M_t.rend(); }
458#endif
459
460 // capacity
461 /** Returns true if the %map is empty. (Thus begin() would equal
462 * end().)
463 */
464 _GLIBCXX_NODISCARD bool
465 empty() const _GLIBCXX_NOEXCEPT
466 { return _M_t.empty(); }
467
468 /** Returns the size of the %map. */
469 size_type
470 size() const _GLIBCXX_NOEXCEPT
471 { return _M_t.size(); }
472
473 /** Returns the maximum size of the %map. */
474 size_type
475 max_size() const _GLIBCXX_NOEXCEPT
476 { return _M_t.max_size(); }
477
478 // [23.3.1.2] element access
479 /**
480 * @brief Subscript ( @c [] ) access to %map data.
481 * @param __k The key for which data should be retrieved.
482 * @return A reference to the data of the (key,data) %pair.
483 *
484 * Allows for easy lookup with the subscript ( @c [] )
485 * operator. Returns data associated with the key specified in
486 * subscript. If the key does not exist, a pair with that key
487 * is created using default values, which is then returned.
488 *
489 * Lookup requires logarithmic time.
490 */
491 mapped_type&
492 operator[](const key_type& __k)
493 {
494 // concept requirements
495 __glibcxx_function_requires(_DefaultConstructibleConcept<mapped_type>)
496
497 iterator __i = lower_bound(__k);
498 // __i->first is greater than or equivalent to __k.
499 if (__i == end() || key_comp()(__k, (*__i).first))
500#if __cplusplus >= 201103L
501 __i = _M_t._M_emplace_hint_unique(__i, std::piecewise_construct,
502 std::tuple<const key_type&>(__k),
503 std::tuple<>());
504#else
505 __i = insert(__i, value_type(__k, mapped_type()));
506#endif
507 return (*__i).second;
508 }
509
510#if __cplusplus >= 201103L
511 mapped_type&
512 operator[](key_type&& __k)
513 {
514 // concept requirements
515 __glibcxx_function_requires(_DefaultConstructibleConcept<mapped_type>)
516
517 iterator __i = lower_bound(__k);
518 // __i->first is greater than or equivalent to __k.
519 if (__i == end() || key_comp()(__k, (*__i).first))
520 __i = _M_t._M_emplace_hint_unique(__i, std::piecewise_construct,
521 std::forward_as_tuple(std::move(__k)),
522 std::tuple<>());
523 return (*__i).second;
524 }
525#endif
526
527 // _GLIBCXX_RESOLVE_LIB_DEFECTS
528 // DR 464. Suggestion for new member functions in standard containers.
529 /**
530 * @brief Access to %map data.
531 * @param __k The key for which data should be retrieved.
532 * @return A reference to the data whose key is equivalent to @a __k, if
533 * such a data is present in the %map.
534 * @throw std::out_of_range If no such data is present.
535 */
536 mapped_type&
537 at(const key_type& __k)
538 {
539 iterator __i = lower_bound(__k);
540 if (__i == end() || key_comp()(__k, (*__i).first))
541 __throw_out_of_range(__N("map::at"));
542 return (*__i).second;
543 }
544
545 const mapped_type&
546 at(const key_type& __k) const
547 {
548 const_iterator __i = lower_bound(__k);
549 if (__i == end() || key_comp()(__k, (*__i).first))
550 __throw_out_of_range(__N("map::at"));
551 return (*__i).second;
552 }
553
554 // modifiers
555#if __cplusplus >= 201103L
556 /**
557 * @brief Attempts to build and insert a std::pair into the %map.
558 *
559 * @param __args Arguments used to generate a new pair instance (see
560 * std::piecewise_contruct for passing arguments to each
561 * part of the pair constructor).
562 *
563 * @return A pair, of which the first element is an iterator that points
564 * to the possibly inserted pair, and the second is a bool that
565 * is true if the pair was actually inserted.
566 *
567 * This function attempts to build and insert a (key, value) %pair into
568 * the %map.
569 * A %map relies on unique keys and thus a %pair is only inserted if its
570 * first element (the key) is not already present in the %map.
571 *
572 * Insertion requires logarithmic time.
573 */
574 template<typename... _Args>
575 std::pair<iterator, bool>
576 emplace(_Args&&... __args)
577 { return _M_t._M_emplace_unique(std::forward<_Args>(__args)...); }
578
579 /**
580 * @brief Attempts to build and insert a std::pair into the %map.
581 *
582 * @param __pos An iterator that serves as a hint as to where the pair
583 * should be inserted.
584 * @param __args Arguments used to generate a new pair instance (see
585 * std::piecewise_contruct for passing arguments to each
586 * part of the pair constructor).
587 * @return An iterator that points to the element with key of the
588 * std::pair built from @a __args (may or may not be that
589 * std::pair).
590 *
591 * This function is not concerned about whether the insertion took place,
592 * and thus does not return a boolean like the single-argument emplace()
593 * does.
594 * Note that the first parameter is only a hint and can potentially
595 * improve the performance of the insertion process. A bad hint would
596 * cause no gains in efficiency.
597 *
598 * See
599 * https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints
600 * for more on @a hinting.
601 *
602 * Insertion requires logarithmic time (if the hint is not taken).
603 */
604 template<typename... _Args>
605 iterator
606 emplace_hint(const_iterator __pos, _Args&&... __args)
607 {
608 return _M_t._M_emplace_hint_unique(__pos,
609 std::forward<_Args>(__args)...);
610 }
611#endif
612
613#if __cplusplus > 201402L
614 /// Extract a node.
615 node_type
616 extract(const_iterator __pos)
617 {
618 __glibcxx_assert(__pos != end());
619 return _M_t.extract(__pos);
620 }
621
622 /// Extract a node.
623 node_type
624 extract(const key_type& __x)
625 { return _M_t.extract(__x); }
626
627 /// Re-insert an extracted node.
628 insert_return_type
629 insert(node_type&& __nh)
630 { return _M_t._M_reinsert_node_unique(std::move(__nh)); }
631
632 /// Re-insert an extracted node.
633 iterator
634 insert(const_iterator __hint, node_type&& __nh)
635 { return _M_t._M_reinsert_node_hint_unique(__hint, std::move(__nh)); }
636
637 template<typename, typename>
638 friend struct std::_Rb_tree_merge_helper;
639
640 template<typename _Cmp2>
641 void
642 merge(map<_Key, _Tp, _Cmp2, _Alloc>& __source)
643 {
644 using _Merge_helper = _Rb_tree_merge_helper<map, _Cmp2>;
645 _M_t._M_merge_unique(_Merge_helper::_S_get_tree(__source));
646 }
647
648 template<typename _Cmp2>
649 void
650 merge(map<_Key, _Tp, _Cmp2, _Alloc>&& __source)
651 { merge(__source); }
652
653 template<typename _Cmp2>
654 void
655 merge(multimap<_Key, _Tp, _Cmp2, _Alloc>& __source)
656 {
657 using _Merge_helper = _Rb_tree_merge_helper<map, _Cmp2>;
658 _M_t._M_merge_unique(_Merge_helper::_S_get_tree(__source));
659 }
660
661 template<typename _Cmp2>
662 void
663 merge(multimap<_Key, _Tp, _Cmp2, _Alloc>&& __source)
664 { merge(__source); }
665#endif // C++17
666
667#if __cplusplus > 201402L
668#define __cpp_lib_map_try_emplace 201411
669 /**
670 * @brief Attempts to build and insert a std::pair into the %map.
671 *
672 * @param __k Key to use for finding a possibly existing pair in
673 * the map.
674 * @param __args Arguments used to generate the .second for a new pair
675 * instance.
676 *
677 * @return A pair, of which the first element is an iterator that points
678 * to the possibly inserted pair, and the second is a bool that
679 * is true if the pair was actually inserted.
680 *
681 * This function attempts to build and insert a (key, value) %pair into
682 * the %map.
683 * A %map relies on unique keys and thus a %pair is only inserted if its
684 * first element (the key) is not already present in the %map.
685 * If a %pair is not inserted, this function has no effect.
686 *
687 * Insertion requires logarithmic time.
688 */
689 template <typename... _Args>
690 pair<iterator, bool>
691 try_emplace(const key_type& __k, _Args&&... __args)
692 {
693 iterator __i = lower_bound(__k);
694 if (__i == end() || key_comp()(__k, (*__i).first))
695 {
696 __i = emplace_hint(__i, std::piecewise_construct,
697 std::forward_as_tuple(__k),
698 std::forward_as_tuple(
699 std::forward<_Args>(__args)...));
700 return {__i, true};
701 }
702 return {__i, false};
703 }
704
705 // move-capable overload
706 template <typename... _Args>
707 pair<iterator, bool>
708 try_emplace(key_type&& __k, _Args&&... __args)
709 {
710 iterator __i = lower_bound(__k);
711 if (__i == end() || key_comp()(__k, (*__i).first))
712 {
713 __i = emplace_hint(__i, std::piecewise_construct,
714 std::forward_as_tuple(std::move(__k)),
715 std::forward_as_tuple(
716 std::forward<_Args>(__args)...));
717 return {__i, true};
718 }
719 return {__i, false};
720 }
721
722 /**
723 * @brief Attempts to build and insert a std::pair into the %map.
724 *
725 * @param __hint An iterator that serves as a hint as to where the
726 * pair should be inserted.
727 * @param __k Key to use for finding a possibly existing pair in
728 * the map.
729 * @param __args Arguments used to generate the .second for a new pair
730 * instance.
731 * @return An iterator that points to the element with key of the
732 * std::pair built from @a __args (may or may not be that
733 * std::pair).
734 *
735 * This function is not concerned about whether the insertion took place,
736 * and thus does not return a boolean like the single-argument
737 * try_emplace() does. However, if insertion did not take place,
738 * this function has no effect.
739 * Note that the first parameter is only a hint and can potentially
740 * improve the performance of the insertion process. A bad hint would
741 * cause no gains in efficiency.
742 *
743 * See
744 * https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints
745 * for more on @a hinting.
746 *
747 * Insertion requires logarithmic time (if the hint is not taken).
748 */
749 template <typename... _Args>
750 iterator
751 try_emplace(const_iterator __hint, const key_type& __k,
752 _Args&&... __args)
753 {
754 iterator __i;
755 auto __true_hint = _M_t._M_get_insert_hint_unique_pos(__hint, __k);
756 if (__true_hint.second)
757 __i = emplace_hint(iterator(__true_hint.second),
758 std::piecewise_construct,
759 std::forward_as_tuple(__k),
760 std::forward_as_tuple(
761 std::forward<_Args>(__args)...));
762 else
763 __i = iterator(__true_hint.first);
764 return __i;
765 }
766
767 // move-capable overload
768 template <typename... _Args>
769 iterator
770 try_emplace(const_iterator __hint, key_type&& __k, _Args&&... __args)
771 {
772 iterator __i;
773 auto __true_hint = _M_t._M_get_insert_hint_unique_pos(__hint, __k);
774 if (__true_hint.second)
775 __i = emplace_hint(iterator(__true_hint.second),
776 std::piecewise_construct,
777 std::forward_as_tuple(std::move(__k)),
778 std::forward_as_tuple(
779 std::forward<_Args>(__args)...));
780 else
781 __i = iterator(__true_hint.first);
782 return __i;
783 }
784#endif
785
786 /**
787 * @brief Attempts to insert a std::pair into the %map.
788 * @param __x Pair to be inserted (see std::make_pair for easy
789 * creation of pairs).
790 *
791 * @return A pair, of which the first element is an iterator that
792 * points to the possibly inserted pair, and the second is
793 * a bool that is true if the pair was actually inserted.
794 *
795 * This function attempts to insert a (key, value) %pair into the %map.
796 * A %map relies on unique keys and thus a %pair is only inserted if its
797 * first element (the key) is not already present in the %map.
798 *
799 * Insertion requires logarithmic time.
800 * @{
801 */
802 std::pair<iterator, bool>
803 insert(const value_type& __x)
804 { return _M_t._M_insert_unique(__x); }
805
806#if __cplusplus >= 201103L
807 // _GLIBCXX_RESOLVE_LIB_DEFECTS
808 // 2354. Unnecessary copying when inserting into maps with braced-init
809 std::pair<iterator, bool>
810 insert(value_type&& __x)
811 { return _M_t._M_insert_unique(std::move(__x)); }
812
813 template<typename _Pair>
814 __enable_if_t<is_constructible<value_type, _Pair>::value,
815 pair<iterator, bool>>
816 insert(_Pair&& __x)
817 { return _M_t._M_emplace_unique(std::forward<_Pair>(__x)); }
818#endif
819 /// @}
820
821#if __cplusplus >= 201103L
822 /**
823 * @brief Attempts to insert a list of std::pairs into the %map.
824 * @param __list A std::initializer_list<value_type> of pairs to be
825 * inserted.
826 *
827 * Complexity similar to that of the range constructor.
828 */
829 void
830 insert(std::initializer_list<value_type> __list)
831 { insert(__list.begin(), __list.end()); }
832#endif
833
834 /**
835 * @brief Attempts to insert a std::pair into the %map.
836 * @param __position An iterator that serves as a hint as to where the
837 * pair should be inserted.
838 * @param __x Pair to be inserted (see std::make_pair for easy creation
839 * of pairs).
840 * @return An iterator that points to the element with key of
841 * @a __x (may or may not be the %pair passed in).
842 *
843
844 * This function is not concerned about whether the insertion
845 * took place, and thus does not return a boolean like the
846 * single-argument insert() does. Note that the first
847 * parameter is only a hint and can potentially improve the
848 * performance of the insertion process. A bad hint would
849 * cause no gains in efficiency.
850 *
851 * See
852 * https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints
853 * for more on @a hinting.
854 *
855 * Insertion requires logarithmic time (if the hint is not taken).
856 * @{
857 */
858 iterator
859#if __cplusplus >= 201103L
860 insert(const_iterator __position, const value_type& __x)
861#else
862 insert(iterator __position, const value_type& __x)
863#endif
864 { return _M_t._M_insert_unique_(__position, __x); }
865
866#if __cplusplus >= 201103L
867 // _GLIBCXX_RESOLVE_LIB_DEFECTS
868 // 2354. Unnecessary copying when inserting into maps with braced-init
869 iterator
870 insert(const_iterator __position, value_type&& __x)
871 { return _M_t._M_insert_unique_(__position, std::move(__x)); }
872
873 template<typename _Pair>
874 __enable_if_t<is_constructible<value_type, _Pair>::value, iterator>
875 insert(const_iterator __position, _Pair&& __x)
876 {
877 return _M_t._M_emplace_hint_unique(__position,
878 std::forward<_Pair>(__x));
879 }
880#endif
881 /// @}
882
883 /**
884 * @brief Template function that attempts to insert a range of elements.
885 * @param __first Iterator pointing to the start of the range to be
886 * inserted.
887 * @param __last Iterator pointing to the end of the range.
888 *
889 * Complexity similar to that of the range constructor.
890 */
891 template<typename _InputIterator>
892 void
893 insert(_InputIterator __first, _InputIterator __last)
894 { _M_t._M_insert_range_unique(__first, __last); }
895
896#if __cplusplus > 201402L
897 /**
898 * @brief Attempts to insert or assign a std::pair into the %map.
899 * @param __k Key to use for finding a possibly existing pair in
900 * the map.
901 * @param __obj Argument used to generate the .second for a pair
902 * instance.
903 *
904 * @return A pair, of which the first element is an iterator that
905 * points to the possibly inserted pair, and the second is
906 * a bool that is true if the pair was actually inserted.
907 *
908 * This function attempts to insert a (key, value) %pair into the %map.
909 * A %map relies on unique keys and thus a %pair is only inserted if its
910 * first element (the key) is not already present in the %map.
911 * If the %pair was already in the %map, the .second of the %pair
912 * is assigned from __obj.
913 *
914 * Insertion requires logarithmic time.
915 */
916 template <typename _Obj>
917 pair<iterator, bool>
918 insert_or_assign(const key_type& __k, _Obj&& __obj)
919 {
920 iterator __i = lower_bound(__k);
921 if (__i == end() || key_comp()(__k, (*__i).first))
922 {
923 __i = emplace_hint(__i, std::piecewise_construct,
924 std::forward_as_tuple(__k),
925 std::forward_as_tuple(
926 std::forward<_Obj>(__obj)));
927 return {__i, true};
928 }
929 (*__i).second = std::forward<_Obj>(__obj);
930 return {__i, false};
931 }
932
933 // move-capable overload
934 template <typename _Obj>
935 pair<iterator, bool>
936 insert_or_assign(key_type&& __k, _Obj&& __obj)
937 {
938 iterator __i = lower_bound(__k);
939 if (__i == end() || key_comp()(__k, (*__i).first))
940 {
941 __i = emplace_hint(__i, std::piecewise_construct,
942 std::forward_as_tuple(std::move(__k)),
943 std::forward_as_tuple(
944 std::forward<_Obj>(__obj)));
945 return {__i, true};
946 }
947 (*__i).second = std::forward<_Obj>(__obj);
948 return {__i, false};
949 }
950
951 /**
952 * @brief Attempts to insert or assign a std::pair into the %map.
953 * @param __hint An iterator that serves as a hint as to where the
954 * pair should be inserted.
955 * @param __k Key to use for finding a possibly existing pair in
956 * the map.
957 * @param __obj Argument used to generate the .second for a pair
958 * instance.
959 *
960 * @return An iterator that points to the element with key of
961 * @a __x (may or may not be the %pair passed in).
962 *
963 * This function attempts to insert a (key, value) %pair into the %map.
964 * A %map relies on unique keys and thus a %pair is only inserted if its
965 * first element (the key) is not already present in the %map.
966 * If the %pair was already in the %map, the .second of the %pair
967 * is assigned from __obj.
968 *
969 * Insertion requires logarithmic time.
970 */
971 template <typename _Obj>
972 iterator
973 insert_or_assign(const_iterator __hint,
974 const key_type& __k, _Obj&& __obj)
975 {
976 iterator __i;
977 auto __true_hint = _M_t._M_get_insert_hint_unique_pos(__hint, __k);
978 if (__true_hint.second)
979 {
980 return emplace_hint(iterator(__true_hint.second),
981 std::piecewise_construct,
982 std::forward_as_tuple(__k),
983 std::forward_as_tuple(
984 std::forward<_Obj>(__obj)));
985 }
986 __i = iterator(__true_hint.first);
987 (*__i).second = std::forward<_Obj>(__obj);
988 return __i;
989 }
990
991 // move-capable overload
992 template <typename _Obj>
993 iterator
994 insert_or_assign(const_iterator __hint, key_type&& __k, _Obj&& __obj)
995 {
996 iterator __i;
997 auto __true_hint = _M_t._M_get_insert_hint_unique_pos(__hint, __k);
998 if (__true_hint.second)
999 {
1000 return emplace_hint(iterator(__true_hint.second),
1001 std::piecewise_construct,
1002 std::forward_as_tuple(std::move(__k)),
1003 std::forward_as_tuple(
1004 std::forward<_Obj>(__obj)));
1005 }
1006 __i = iterator(__true_hint.first);
1007 (*__i).second = std::forward<_Obj>(__obj);
1008 return __i;
1009 }
1010#endif
1011
1012#if __cplusplus >= 201103L
1013 // _GLIBCXX_RESOLVE_LIB_DEFECTS
1014 // DR 130. Associative erase should return an iterator.
1015 /**
1016 * @brief Erases an element from a %map.
1017 * @param __position An iterator pointing to the element to be erased.
1018 * @return An iterator pointing to the element immediately following
1019 * @a position prior to the element being erased. If no such
1020 * element exists, end() is returned.
1021 *
1022 * This function erases an element, pointed to by the given
1023 * iterator, from a %map. Note that this function only erases
1024 * the element, and that if the element is itself a pointer,
1025 * the pointed-to memory is not touched in any way. Managing
1026 * the pointer is the user's responsibility.
1027 *
1028 * @{
1029 */
1030 iterator
1031 erase(const_iterator __position)
1032 { return _M_t.erase(__position); }
1033
1034 // LWG 2059
1035 _GLIBCXX_ABI_TAG_CXX11
1036 iterator
1037 erase(iterator __position)
1038 { return _M_t.erase(__position); }
1039 /// @}
1040#else
1041 /**
1042 * @brief Erases an element from a %map.
1043 * @param __position An iterator pointing to the element to be erased.
1044 *
1045 * This function erases an element, pointed to by the given
1046 * iterator, from a %map. Note that this function only erases
1047 * the element, and that if the element is itself a pointer,
1048 * the pointed-to memory is not touched in any way. Managing
1049 * the pointer is the user's responsibility.
1050 */
1051 void
1052 erase(iterator __position)
1053 { _M_t.erase(__position); }
1054#endif
1055
1056 /**
1057 * @brief Erases elements according to the provided key.
1058 * @param __x Key of element to be erased.
1059 * @return The number of elements erased.
1060 *
1061 * This function erases all the elements located by the given key from
1062 * a %map.
1063 * Note that this function only erases the element, and that if
1064 * the element is itself a pointer, the pointed-to memory is not touched
1065 * in any way. Managing the pointer is the user's responsibility.
1066 */
1067 size_type
1068 erase(const key_type& __x)
1069 { return _M_t.erase(__x); }
1070
1071#if __cplusplus >= 201103L
1072 // _GLIBCXX_RESOLVE_LIB_DEFECTS
1073 // DR 130. Associative erase should return an iterator.
1074 /**
1075 * @brief Erases a [first,last) range of elements from a %map.
1076 * @param __first Iterator pointing to the start of the range to be
1077 * erased.
1078 * @param __last Iterator pointing to the end of the range to
1079 * be erased.
1080 * @return The iterator @a __last.
1081 *
1082 * This function erases a sequence of elements from a %map.
1083 * Note that this function only erases the element, and that if
1084 * the element is itself a pointer, the pointed-to memory is not touched
1085 * in any way. Managing the pointer is the user's responsibility.
1086 */
1087 iterator
1088 erase(const_iterator __first, const_iterator __last)
1089 { return _M_t.erase(__first, __last); }
1090#else
1091 /**
1092 * @brief Erases a [__first,__last) range of elements from a %map.
1093 * @param __first Iterator pointing to the start of the range to be
1094 * erased.
1095 * @param __last Iterator pointing to the end of the range to
1096 * be erased.
1097 *
1098 * This function erases a sequence of elements from a %map.
1099 * Note that this function only erases the element, and that if
1100 * the element is itself a pointer, the pointed-to memory is not touched
1101 * in any way. Managing the pointer is the user's responsibility.
1102 */
1103 void
1104 erase(iterator __first, iterator __last)
1105 { _M_t.erase(__first, __last); }
1106#endif
1107
1108 /**
1109 * @brief Swaps data with another %map.
1110 * @param __x A %map of the same element and allocator types.
1111 *
1112 * This exchanges the elements between two maps in constant
1113 * time. (It is only swapping a pointer, an integer, and an
1114 * instance of the @c Compare type (which itself is often
1115 * stateless and empty), so it should be quite fast.) Note
1116 * that the global std::swap() function is specialized such
1117 * that std::swap(m1,m2) will feed to this function.
1118 *
1119 * Whether the allocators are swapped depends on the allocator traits.
1120 */
1121 void
1122 swap(map& __x)
1123 _GLIBCXX_NOEXCEPT_IF(__is_nothrow_swappable<_Compare>::value)
1124 { _M_t.swap(__x._M_t); }
1125
1126 /**
1127 * Erases all elements in a %map. Note that this function only
1128 * erases the elements, and that if the elements themselves are
1129 * pointers, the pointed-to memory is not touched in any way.
1130 * Managing the pointer is the user's responsibility.
1131 */
1132 void
1133 clear() _GLIBCXX_NOEXCEPT
1134 { _M_t.clear(); }
1135
1136 // observers
1137 /**
1138 * Returns the key comparison object out of which the %map was
1139 * constructed.
1140 */
1141 key_compare
1142 key_comp() const
1143 { return _M_t.key_comp(); }
1144
1145 /**
1146 * Returns a value comparison object, built from the key comparison
1147 * object out of which the %map was constructed.
1148 */
1149 value_compare
1150 value_comp() const
1151 { return value_compare(_M_t.key_comp()); }
1152
1153 // [23.3.1.3] map operations
1154
1155 ///@{
1156 /**
1157 * @brief Tries to locate an element in a %map.
1158 * @param __x Key of (key, value) %pair to be located.
1159 * @return Iterator pointing to sought-after element, or end() if not
1160 * found.
1161 *
1162 * This function takes a key and tries to locate the element with which
1163 * the key matches. If successful the function returns an iterator
1164 * pointing to the sought after %pair. If unsuccessful it returns the
1165 * past-the-end ( @c end() ) iterator.
1166 */
1167
1168 iterator
1169 find(const key_type& __x)
1170 { return _M_t.find(__x); }
1171
1172#if __cplusplus > 201103L
1173 template<typename _Kt>
1174 auto
1175 find(const _Kt& __x) -> decltype(_M_t._M_find_tr(__x))
1176 { return _M_t._M_find_tr(__x); }
1177#endif
1178 ///@}
1179
1180 ///@{
1181 /**
1182 * @brief Tries to locate an element in a %map.
1183 * @param __x Key of (key, value) %pair to be located.
1184 * @return Read-only (constant) iterator pointing to sought-after
1185 * element, or end() if not found.
1186 *
1187 * This function takes a key and tries to locate the element with which
1188 * the key matches. If successful the function returns a constant
1189 * iterator pointing to the sought after %pair. If unsuccessful it
1190 * returns the past-the-end ( @c end() ) iterator.
1191 */
1192
1193 const_iterator
1194 find(const key_type& __x) const
1195 { return _M_t.find(__x); }
1196
1197#if __cplusplus > 201103L
1198 template<typename _Kt>
1199 auto
1200 find(const _Kt& __x) const -> decltype(_M_t._M_find_tr(__x))
1201 { return _M_t._M_find_tr(__x); }
1202#endif
1203 ///@}
1204
1205 ///@{
1206 /**
1207 * @brief Finds the number of elements with given key.
1208 * @param __x Key of (key, value) pairs to be located.
1209 * @return Number of elements with specified key.
1210 *
1211 * This function only makes sense for multimaps; for map the result will
1212 * either be 0 (not present) or 1 (present).
1213 */
1214 size_type
1215 count(const key_type& __x) const
1216 { return _M_t.find(__x) == _M_t.end() ? 0 : 1; }
1217
1218#if __cplusplus > 201103L
1219 template<typename _Kt>
1220 auto
1221 count(const _Kt& __x) const -> decltype(_M_t._M_count_tr(__x))
1222 { return _M_t._M_count_tr(__x); }
1223#endif
1224 ///@}
1225
1226#if __cplusplus > 201703L
1227 ///@{
1228 /**
1229 * @brief Finds whether an element with the given key exists.
1230 * @param __x Key of (key, value) pairs to be located.
1231 * @return True if there is an element with the specified key.
1232 */
1233 bool
1234 contains(const key_type& __x) const
1235 { return _M_t.find(__x) != _M_t.end(); }
1236
1237 template<typename _Kt>
1238 auto
1239 contains(const _Kt& __x) const
1240 -> decltype(_M_t._M_find_tr(__x), void(), true)
1241 { return _M_t._M_find_tr(__x) != _M_t.end(); }
1242 ///@}
1243#endif
1244
1245 ///@{
1246 /**
1247 * @brief Finds the beginning of a subsequence matching given key.
1248 * @param __x Key of (key, value) pair to be located.
1249 * @return Iterator pointing to first element equal to or greater
1250 * than key, or end().
1251 *
1252 * This function returns the first element of a subsequence of elements
1253 * that matches the given key. If unsuccessful it returns an iterator
1254 * pointing to the first element that has a greater value than given key
1255 * or end() if no such element exists.
1256 */
1257 iterator
1258 lower_bound(const key_type& __x)
1259 { return _M_t.lower_bound(__x); }
1260
1261#if __cplusplus > 201103L
1262 template<typename _Kt>
1263 auto
1264 lower_bound(const _Kt& __x)
1265 -> decltype(iterator(_M_t._M_lower_bound_tr(__x)))
1266 { return iterator(_M_t._M_lower_bound_tr(__x)); }
1267#endif
1268 ///@}
1269
1270 ///@{
1271 /**
1272 * @brief Finds the beginning of a subsequence matching given key.
1273 * @param __x Key of (key, value) pair to be located.
1274 * @return Read-only (constant) iterator pointing to first element
1275 * equal to or greater than key, or end().
1276 *
1277 * This function returns the first element of a subsequence of elements
1278 * that matches the given key. If unsuccessful it returns an iterator
1279 * pointing to the first element that has a greater value than given key
1280 * or end() if no such element exists.
1281 */
1282 const_iterator
1283 lower_bound(const key_type& __x) const
1284 { return _M_t.lower_bound(__x); }
1285
1286#if __cplusplus > 201103L
1287 template<typename _Kt>
1288 auto
1289 lower_bound(const _Kt& __x) const
1290 -> decltype(const_iterator(_M_t._M_lower_bound_tr(__x)))
1291 { return const_iterator(_M_t._M_lower_bound_tr(__x)); }
1292#endif
1293 ///@}
1294
1295 ///@{
1296 /**
1297 * @brief Finds the end of a subsequence matching given key.
1298 * @param __x Key of (key, value) pair to be located.
1299 * @return Iterator pointing to the first element
1300 * greater than key, or end().
1301 */
1302 iterator
1303 upper_bound(const key_type& __x)
1304 { return _M_t.upper_bound(__x); }
1305
1306#if __cplusplus > 201103L
1307 template<typename _Kt>
1308 auto
1309 upper_bound(const _Kt& __x)
1310 -> decltype(iterator(_M_t._M_upper_bound_tr(__x)))
1311 { return iterator(_M_t._M_upper_bound_tr(__x)); }
1312#endif
1313 ///@}
1314
1315 ///@{
1316 /**
1317 * @brief Finds the end of a subsequence matching given key.
1318 * @param __x Key of (key, value) pair to be located.
1319 * @return Read-only (constant) iterator pointing to first iterator
1320 * greater than key, or end().
1321 */
1322 const_iterator
1323 upper_bound(const key_type& __x) const
1324 { return _M_t.upper_bound(__x); }
1325
1326#if __cplusplus > 201103L
1327 template<typename _Kt>
1328 auto
1329 upper_bound(const _Kt& __x) const
1330 -> decltype(const_iterator(_M_t._M_upper_bound_tr(__x)))
1331 { return const_iterator(_M_t._M_upper_bound_tr(__x)); }
1332#endif
1333 ///@}
1334
1335 ///@{
1336 /**
1337 * @brief Finds a subsequence matching given key.
1338 * @param __x Key of (key, value) pairs to be located.
1339 * @return Pair of iterators that possibly points to the subsequence
1340 * matching given key.
1341 *
1342 * This function is equivalent to
1343 * @code
1344 * std::make_pair(c.lower_bound(val),
1345 * c.upper_bound(val))
1346 * @endcode
1347 * (but is faster than making the calls separately).
1348 *
1349 * This function probably only makes sense for multimaps.
1350 */
1351 std::pair<iterator, iterator>
1352 equal_range(const key_type& __x)
1353 { return _M_t.equal_range(__x); }
1354
1355#if __cplusplus > 201103L
1356 template<typename _Kt>
1357 auto
1358 equal_range(const _Kt& __x)
1359 -> decltype(pair<iterator, iterator>(_M_t._M_equal_range_tr(__x)))
1360 { return pair<iterator, iterator>(_M_t._M_equal_range_tr(__x)); }
1361#endif
1362 ///@}
1363
1364 ///@{
1365 /**
1366 * @brief Finds a subsequence matching given key.
1367 * @param __x Key of (key, value) pairs to be located.
1368 * @return Pair of read-only (constant) iterators that possibly points
1369 * to the subsequence matching given key.
1370 *
1371 * This function is equivalent to
1372 * @code
1373 * std::make_pair(c.lower_bound(val),
1374 * c.upper_bound(val))
1375 * @endcode
1376 * (but is faster than making the calls separately).
1377 *
1378 * This function probably only makes sense for multimaps.
1379 */
1380 std::pair<const_iterator, const_iterator>
1381 equal_range(const key_type& __x) const
1382 { return _M_t.equal_range(__x); }
1383
1384#if __cplusplus > 201103L
1385 template<typename _Kt>
1386 auto
1387 equal_range(const _Kt& __x) const
1388 -> decltype(pair<const_iterator, const_iterator>(
1389 _M_t._M_equal_range_tr(__x)))
1390 {
1391 return pair<const_iterator, const_iterator>(
1392 _M_t._M_equal_range_tr(__x));
1393 }
1394#endif
1395 ///@}
1396
1397 template<typename _K1, typename _T1, typename _C1, typename _A1>
1398 friend bool
1399 operator==(const map<_K1, _T1, _C1, _A1>&,
1400 const map<_K1, _T1, _C1, _A1>&);
1401
1402#if __cpp_lib_three_way_comparison
1403 template<typename _K1, typename _T1, typename _C1, typename _A1>
1404 friend __detail::__synth3way_t<pair<const _K1, _T1>>
1405 operator<=>(const map<_K1, _T1, _C1, _A1>&,
1406 const map<_K1, _T1, _C1, _A1>&);
1407#else
1408 template<typename _K1, typename _T1, typename _C1, typename _A1>
1409 friend bool
1410 operator<(const map<_K1, _T1, _C1, _A1>&,
1411 const map<_K1, _T1, _C1, _A1>&);
1412#endif
1413 };
1414
1415
1416#if __cpp_deduction_guides >= 201606
1417
1418 template<typename _InputIterator,
1419 typename _Compare = less<__iter_key_t<_InputIterator>>,
1420 typename _Allocator = allocator<__iter_to_alloc_t<_InputIterator>>,
1421 typename = _RequireInputIter<_InputIterator>,
1422 typename = _RequireNotAllocator<_Compare>,
1423 typename = _RequireAllocator<_Allocator>>
1424 map(_InputIterator, _InputIterator,
1425 _Compare = _Compare(), _Allocator = _Allocator())
1426 -> map<__iter_key_t<_InputIterator>, __iter_val_t<_InputIterator>,
1427 _Compare, _Allocator>;
1428
1429 template<typename _Key, typename _Tp, typename _Compare = less<_Key>,
1430 typename _Allocator = allocator<pair<const _Key, _Tp>>,
1431 typename = _RequireNotAllocator<_Compare>,
1432 typename = _RequireAllocator<_Allocator>>
1433 map(initializer_list<pair<_Key, _Tp>>,
1434 _Compare = _Compare(), _Allocator = _Allocator())
1435 -> map<_Key, _Tp, _Compare, _Allocator>;
1436
1437 template <typename _InputIterator, typename _Allocator,
1438 typename = _RequireInputIter<_InputIterator>,
1439 typename = _RequireAllocator<_Allocator>>
1440 map(_InputIterator, _InputIterator, _Allocator)
1441 -> map<__iter_key_t<_InputIterator>, __iter_val_t<_InputIterator>,
1442 less<__iter_key_t<_InputIterator>>, _Allocator>;
1443
1444 template<typename _Key, typename _Tp, typename _Allocator,
1445 typename = _RequireAllocator<_Allocator>>
1446 map(initializer_list<pair<_Key, _Tp>>, _Allocator)
1447 -> map<_Key, _Tp, less<_Key>, _Allocator>;
1448
1449#endif // deduction guides
1450
1451 /**
1452 * @brief Map equality comparison.
1453 * @param __x A %map.
1454 * @param __y A %map of the same type as @a x.
1455 * @return True iff the size and elements of the maps are equal.
1456 *
1457 * This is an equivalence relation. It is linear in the size of the
1458 * maps. Maps are considered equivalent if their sizes are equal,
1459 * and if corresponding elements compare equal.
1460 */
1461 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
1462 inline bool
1463 operator==(const map<_Key, _Tp, _Compare, _Alloc>& __x,
1464 const map<_Key, _Tp, _Compare, _Alloc>& __y)
1465 { return __x._M_t == __y._M_t; }
1466
1467#if __cpp_lib_three_way_comparison
1468 /**
1469 * @brief Map ordering relation.
1470 * @param __x A `map`.
1471 * @param __y A `map` of the same type as `x`.
1472 * @return A value indicating whether `__x` is less than, equal to,
1473 * greater than, or incomparable with `__y`.
1474 *
1475 * This is a total ordering relation. It is linear in the size of the
1476 * maps. The elements must be comparable with @c <.
1477 *
1478 * See `std::lexicographical_compare_three_way()` for how the determination
1479 * is made. This operator is used to synthesize relational operators like
1480 * `<` and `>=` etc.
1481 */
1482 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
1483 inline __detail::__synth3way_t<pair<const _Key, _Tp>>
1484 operator<=>(const map<_Key, _Tp, _Compare, _Alloc>& __x,
1485 const map<_Key, _Tp, _Compare, _Alloc>& __y)
1486 { return __x._M_t <=> __y._M_t; }
1487#else
1488 /**
1489 * @brief Map ordering relation.
1490 * @param __x A %map.
1491 * @param __y A %map of the same type as @a x.
1492 * @return True iff @a x is lexicographically less than @a y.
1493 *
1494 * This is a total ordering relation. It is linear in the size of the
1495 * maps. The elements must be comparable with @c <.
1496 *
1497 * See std::lexicographical_compare() for how the determination is made.
1498 */
1499 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
1500 inline bool
1501 operator<(const map<_Key, _Tp, _Compare, _Alloc>& __x,
1502 const map<_Key, _Tp, _Compare, _Alloc>& __y)
1503 { return __x._M_t < __y._M_t; }
1504
1505 /// Based on operator==
1506 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
1507 inline bool
1508 operator!=(const map<_Key, _Tp, _Compare, _Alloc>& __x,
1509 const map<_Key, _Tp, _Compare, _Alloc>& __y)
1510 { return !(__x == __y); }
1511
1512 /// Based on operator<
1513 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
1514 inline bool
1515 operator>(const map<_Key, _Tp, _Compare, _Alloc>& __x,
1516 const map<_Key, _Tp, _Compare, _Alloc>& __y)
1517 { return __y < __x; }
1518
1519 /// Based on operator<
1520 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
1521 inline bool
1522 operator<=(const map<_Key, _Tp, _Compare, _Alloc>& __x,
1523 const map<_Key, _Tp, _Compare, _Alloc>& __y)
1524 { return !(__y < __x); }
1525
1526 /// Based on operator<
1527 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
1528 inline bool
1529 operator>=(const map<_Key, _Tp, _Compare, _Alloc>& __x,
1530 const map<_Key, _Tp, _Compare, _Alloc>& __y)
1531 { return !(__x < __y); }
1532#endif // three-way comparison
1533
1534 /// See std::map::swap().
1535 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
1536 inline void
1537 swap(map<_Key, _Tp, _Compare, _Alloc>& __x,
1538 map<_Key, _Tp, _Compare, _Alloc>& __y)
1539 _GLIBCXX_NOEXCEPT_IF(noexcept(__x.swap(__y)))
1540 { __x.swap(__y); }
1541
1542_GLIBCXX_END_NAMESPACE_CONTAINER
1543
1544#if __cplusplus > 201402L
1545 // Allow std::map access to internals of compatible maps.
1546 template<typename _Key, typename _Val, typename _Cmp1, typename _Alloc,
1547 typename _Cmp2>
1548 struct
1549 _Rb_tree_merge_helper<_GLIBCXX_STD_C::map<_Key, _Val, _Cmp1, _Alloc>,
1550 _Cmp2>
1551 {
1552 private:
1553 friend class _GLIBCXX_STD_C::map<_Key, _Val, _Cmp1, _Alloc>;
1554
1555 static auto&
1556 _S_get_tree(_GLIBCXX_STD_C::map<_Key, _Val, _Cmp2, _Alloc>& __map)
1557 { return __map._M_t; }
1558
1559 static auto&
1560 _S_get_tree(_GLIBCXX_STD_C::multimap<_Key, _Val, _Cmp2, _Alloc>& __map)
1561 { return __map._M_t; }
1562 };
1563#endif // C++17
1564
1565_GLIBCXX_END_NAMESPACE_VERSION
1566} // namespace std
1567
1568#endif /* _STL_MAP_H */
1569