1 // Map implementation -*- C++ -*-
3 // Copyright (C) 2001, 2002 Free Software Foundation, Inc.
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 2, or (at your option)
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.
16 // You should have received a copy of the GNU General Public License along
17 // with this library; see the file COPYING. If not, write to the Free
18 // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
21 // As a special exception, you may use this file as part of a free software
22 // library without restriction. Specifically, if other files instantiate
23 // templates or use macros or inline functions from this file, or you compile
24 // this file and link it with other files to produce an executable, this
25 // file does not by itself cause the resulting executable to be covered by
26 // the GNU General Public License. This exception does not however
27 // invalidate any other reasons why the executable file might be covered by
28 // the GNU General Public License.
33 * Hewlett-Packard Company
35 * Permission to use, copy, modify, distribute and sell this software
36 * and its documentation for any purpose is hereby granted without fee,
37 * provided that the above copyright notice appear in all copies and
38 * that both that copyright notice and this permission notice appear
39 * in supporting documentation. Hewlett-Packard Company makes no
40 * representations about the suitability of this software for any
41 * purpose. It is provided "as is" without express or implied warranty.
44 * Copyright (c) 1996,1997
45 * Silicon Graphics Computer Systems, Inc.
47 * Permission to use, copy, modify, distribute and sell this software
48 * and its documentation for any purpose is hereby granted without fee,
49 * provided that the above copyright notice appear in all copies and
50 * that both that copyright notice and this permission notice appear
51 * in supporting documentation. Silicon Graphics makes no
52 * representations about the suitability of this software for any
53 * purpose. It is provided "as is" without express or implied warranty.
57 * This is an internal header file, included by other library headers.
58 * You should not attempt to use it directly.
64 #include <bits/concept_check.h>
69 * @brief A standard container made up of (key,value) pairs, which can be
70 * retrieved based on a key, in logarithmic time.
73 * @ingroup Assoc_containers
75 * Meets the requirements of a <a href="tables.html#65">container</a>, a
76 * <a href="tables.html#66">reversible container</a>, and an
77 * <a href="tables.html#69">associative container</a> (using unique keys).
78 * For a @c map<Key,T> the key_type is Key, the mapped_type is T, and the
79 * value_type is std::pair<const Key,T>.
81 * Maps support bidirectional iterators.
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).
89 template <typename _Key
, typename _Tp
, typename _Compare
= less
<_Key
>,
90 typename _Alloc
= allocator
<pair
<const _Key
, _Tp
> > >
93 // concept requirements
94 __glibcxx_class_requires(_Tp
, _SGIAssignableConcept
)
95 __glibcxx_class_requires4(_Compare
, bool, _Key
, _Key
, _BinaryFunctionConcept
)
98 typedef _Key key_type
;
99 typedef _Tp mapped_type
;
100 typedef pair
<const _Key
, _Tp
> value_type
;
101 typedef _Compare key_compare
;
104 : public binary_function
<value_type
, value_type
, bool>
106 friend class map
<_Key
,_Tp
,_Compare
,_Alloc
>;
109 value_compare(_Compare __c
) : comp(__c
) {}
111 bool operator()(const value_type
& __x
, const value_type
& __y
) const
112 { return comp(__x
.first
, __y
.first
); }
116 /// @if maint This turns a red-black tree into a [multi]map. @endif
117 typedef _Rb_tree
<key_type
, value_type
,
118 _Select1st
<value_type
>, key_compare
, _Alloc
> _Rep_type
;
119 /// @if maint The actual tree structure. @endif
123 // many of these are specified differently in ISO, but the following are
124 // "functionally equivalent"
125 typedef typename
_Rep_type::allocator_type allocator_type
;
126 typedef typename
_Rep_type::reference reference
;
127 typedef typename
_Rep_type::const_reference const_reference
;
128 typedef typename
_Rep_type::iterator iterator
;
129 typedef typename
_Rep_type::const_iterator const_iterator
;
130 typedef typename
_Rep_type::size_type size_type
;
131 typedef typename
_Rep_type::difference_type difference_type
;
132 typedef typename
_Rep_type::pointer pointer
;
133 typedef typename
_Rep_type::const_pointer const_pointer
;
134 typedef typename
_Rep_type::reverse_iterator reverse_iterator
;
135 typedef typename
_Rep_type::const_reverse_iterator const_reverse_iterator
;
138 // [23.3.1.1] construct/copy/destroy
139 // (get_allocator() is normally listed in this section, but seems to have
140 // been accidentally omitted in the printed standard)
142 * @brief Default constructor creates no elements.
144 map() : _M_t(_Compare(), allocator_type()) { }
146 // for some reason this was made a separate function
148 * @brief Default constructor creates no elements.
151 map(const _Compare
& __comp
, const allocator_type
& __a
= allocator_type())
152 : _M_t(__comp
, __a
) { }
155 * @brief Map copy constructor.
156 * @param x A %map of identical element and allocator types.
158 * The newly-created %map uses a copy of the allocation object used
165 * @brief Builds a %map from a range.
166 * @param first An input iterator.
167 * @param last An input iterator.
169 * Create a %map consisting of copies of the elements from [first,last).
170 * This is linear in N if the range is already sorted, and NlogN
171 * otherwise (where N is distance(first,last)).
173 template <typename _InputIterator
>
174 map(_InputIterator __first
, _InputIterator __last
)
175 : _M_t(_Compare(), allocator_type())
176 { _M_t
.insert_unique(__first
, __last
); }
179 * @brief Builds a %map from a range.
180 * @param first An input iterator.
181 * @param last An input iterator.
182 * @param comp A comparison functor.
183 * @param a An allocator object.
185 * Create a %map consisting of copies of the elements from [first,last).
186 * This is linear in N if the range is already sorted, and NlogN
187 * otherwise (where N is distance(first,last)).
189 template <typename _InputIterator
>
190 map(_InputIterator __first
, _InputIterator __last
,
191 const _Compare
& __comp
, const allocator_type
& __a
= allocator_type())
193 { _M_t
.insert_unique(__first
, __last
); }
195 // FIXME There is no dtor declared, but we should have something generated
196 // by Doxygen. I don't know what tags to add to this paragraph to make
199 * The dtor only erases the elements, and note that if the elements
200 * themselves are pointers, the pointed-to memory is not touched in any
201 * way. Managing the pointer is the user's responsibilty.
205 * @brief Map assignment operator.
206 * @param x A %map of identical element and allocator types.
208 * All the elements of @a x are copied, but unlike the copy constructor,
209 * the allocator object is not copied.
212 operator=(const map
& __x
)
218 /// Get a copy of the memory allocation object.
220 get_allocator() const { return _M_t
.get_allocator(); }
224 * Returns a read/write iterator that points to the first pair in the %map.
225 * Iteration is done in ascending order according to the keys.
228 begin() { return _M_t
.begin(); }
231 * Returns a read-only (constant) iterator that points to the first pair
232 * in the %map. Iteration is done in ascending order according to the
236 begin() const { return _M_t
.begin(); }
239 * Returns a read/write iterator that points one past the last pair in the
240 * %map. Iteration is done in ascending order according to the keys.
243 end() { return _M_t
.end(); }
246 * Returns a read-only (constant) iterator that points one past the last
247 * pair in the %map. Iteration is done in ascending order according to the
251 end() const { return _M_t
.end(); }
254 * Returns a read/write reverse iterator that points to the last pair in
255 * the %map. Iteration is done in descending order according to the keys.
258 rbegin() { return _M_t
.rbegin(); }
261 * Returns a read-only (constant) reverse iterator that points to the last
262 * pair in the %map. Iteration is done in descending order according to
265 const_reverse_iterator
266 rbegin() const { return _M_t
.rbegin(); }
269 * Returns a read/write reverse iterator that points to one before the
270 * first pair in the %map. Iteration is done in descending order according
274 rend() { return _M_t
.rend(); }
277 * Returns a read-only (constant) reverse iterator that points to one
278 * before the first pair in the %map. Iteration is done in descending
279 * order according to the keys.
281 const_reverse_iterator
282 rend() const { return _M_t
.rend(); }
285 /** Returns true if the %map is empty. (Thus begin() would equal end().) */
287 empty() const { return _M_t
.empty(); }
289 /** Returns the size of the %map. */
291 size() const { return _M_t
.size(); }
293 /** Returns the maximum size of the %map. */
295 max_size() const { return _M_t
.max_size(); }
297 // [23.3.1.2] element access
299 * @brief Subscript ( @c [] ) access to %map data.
300 * @param k The key for which data should be retrieved.
301 * @return A reference to the data of the (key,data) %pair.
303 * Allows for easy lookup with the subscript ( @c [] ) operator. Returns
304 * data associated with the key specified in subscript. If the key does
305 * not exist, a pair with that key is created using default values, which
308 * Lookup requires logarithmic time.
311 operator[](const key_type
& __k
)
313 // concept requirements
314 __glibcxx_function_requires(_DefaultConstructibleConcept
<mapped_type
>)
316 iterator __i
= lower_bound(__k
);
317 // __i->first is greater than or equivalent to __k.
318 if (__i
== end() || key_comp()(__k
, (*__i
).first
))
319 __i
= insert(__i
, value_type(__k
, mapped_type()));
320 return (*__i
).second
;
325 * @brief Attempts to insert a std::pair into the %map.
326 * @param x Pair to be inserted (see std::make_pair for easy creation of
328 * @return A pair, of which the first element is an iterator that points
329 * to the possibly inserted pair, and the second is a bool that
330 * is true if the pair was actually inserted.
332 * This function attempts to insert a (key, value) %pair into the %map.
333 * A %map relies on unique keys and thus a %pair is only inserted if its
334 * first element (the key) is not already present in the %map.
336 * Insertion requires logarithmic time.
339 insert(const value_type
& __x
)
340 { return _M_t
.insert_unique(__x
); }
343 * @brief Attempts to insert a std::pair into the %map.
344 * @param position An iterator that serves as a hint as to where the
345 * pair should be inserted.
346 * @param x Pair to be inserted (see std::make_pair for easy creation of
348 * @return An iterator that points to the element with key of @a x (may
349 * or may not be the %pair passed in).
351 * This function is not concerned about whether the insertion took place,
352 * and thus does not return a boolean like the single-argument
353 * insert() does. Note that the first parameter is only a hint and can
354 * potentially improve the performance of the insertion process. A bad
355 * hint would cause no gains in efficiency.
357 * See http://gcc.gnu.org/onlinedocs/libstdc++/23_containers/howto.html#4
358 * for more on "hinting".
360 * Insertion requires logarithmic time (if the hint is not taken).
363 insert(iterator position
, const value_type
& __x
)
364 { return _M_t
.insert_unique(position
, __x
); }
367 * @brief A template function that attemps to insert a range of elements.
368 * @param first Iterator pointing to the start of the range to be
370 * @param last Iterator pointing to the end of the range.
372 * Complexity similar to that of the range constructor.
374 template <typename _InputIterator
>
376 insert(_InputIterator __first
, _InputIterator __last
)
377 { _M_t
.insert_unique(__first
, __last
); }
380 * @brief Erases an element from a %map.
381 * @param position An iterator pointing to the element to be erased.
383 * This function erases an element, pointed to by the given iterator, from
384 * a %map. Note that this function only erases the element, and that if
385 * the element is itself a pointer, the pointed-to memory is not touched
386 * in any way. Managing the pointer is the user's responsibilty.
389 erase(iterator __position
) { _M_t
.erase(__position
); }
392 * @brief Erases elements according to the provided key.
393 * @param x Key of element to be erased.
394 * @return The number of elements erased.
396 * This function erases all the elements located by the given key from
398 * Note that this function only erases the element, and that if
399 * the element is itself a pointer, the pointed-to memory is not touched
400 * in any way. Managing the pointer is the user's responsibilty.
403 erase(const key_type
& __x
) { return _M_t
.erase(__x
); }
406 * @brief Erases a [first,last) range of elements from a %map.
407 * @param first Iterator pointing to the start of the range to be erased.
408 * @param last Iterator pointing to the end of the range to be erased.
410 * This function erases a sequence of elements from a %map.
411 * Note that this function only erases the element, and that if
412 * the element is itself a pointer, the pointed-to memory is not touched
413 * in any way. Managing the pointer is the user's responsibilty.
416 erase(iterator __first
, iterator __last
) { _M_t
.erase(__first
, __last
); }
419 * @brief Swaps data with another %map.
420 * @param x A %map of the same element and allocator types.
422 * This exchanges the elements between two maps in constant time.
423 * (It is only swapping a pointer, an integer, and an instance of
424 * the @c Compare type (which itself is often stateless and empty), so it
425 * should be quite fast.)
426 * Note that the global std::swap() function is specialized such that
427 * std::swap(m1,m2) will feed to this function.
430 swap(map
& __x
) { _M_t
.swap(__x
._M_t
); }
433 * Erases all elements in a %map. Note that this function only erases
434 * the elements, and that if the elements themselves are pointers, the
435 * pointed-to memory is not touched in any way. Managing the pointer is
436 * the user's responsibilty.
439 clear() { _M_t
.clear(); }
443 * Returns the key comparison object out of which the %map was constructed.
446 key_comp() const { return _M_t
.key_comp(); }
449 * Returns a value comparison object, built from the key comparison
450 * object out of which the %map was constructed.
453 value_comp() const { return value_compare(_M_t
.key_comp()); }
455 // [23.3.1.3] map operations
457 * @brief Tries to locate an element in a %map.
458 * @param x Key of (key, value) %pair to be located.
459 * @return Iterator pointing to sought-after element, or end() if not
462 * This function takes a key and tries to locate the element with which
463 * the key matches. If successful the function returns an iterator
464 * pointing to the sought after %pair. If unsuccessful it returns the
465 * past-the-end ( @c end() ) iterator.
468 find(const key_type
& __x
) { return _M_t
.find(__x
); }
471 * @brief Tries to locate an element in a %map.
472 * @param x Key of (key, value) %pair to be located.
473 * @return Read-only (constant) iterator pointing to sought-after
474 * element, or end() if not found.
476 * This function takes a key and tries to locate the element with which
477 * the key matches. If successful the function returns a constant iterator
478 * pointing to the sought after %pair. If unsuccessful it returns the
479 * past-the-end ( @c end() ) iterator.
482 find(const key_type
& __x
) const { return _M_t
.find(__x
); }
485 * @brief Finds the number of elements with given key.
486 * @param x Key of (key, value) pairs to be located.
487 * @return Number of elements with specified key.
489 * This function only makes sense for multimaps; for map the result will
490 * either be 0 (not present) or 1 (present).
493 count(const key_type
& __x
) const
494 { return _M_t
.find(__x
) == _M_t
.end() ? 0 : 1; }
497 * @brief Finds the beginning of a subsequence matching given key.
498 * @param x Key of (key, value) pair to be located.
499 * @return Iterator pointing to first element equal to or greater
500 * than key, or end().
502 * This function returns the first element of a subsequence of elements
503 * that matches the given key. If unsuccessful it returns an iterator
504 * pointing to the first element that has a greater value than given key
505 * or end() if no such element exists.
508 lower_bound(const key_type
& __x
) { return _M_t
.lower_bound(__x
); }
511 * @brief Finds the beginning of a subsequence matching given key.
512 * @param x Key of (key, value) pair to be located.
513 * @return Read-only (constant) iterator pointing to first element
514 * equal to or greater than key, or end().
516 * This function returns the first element of a subsequence of elements
517 * that matches the given key. If unsuccessful it returns an iterator
518 * pointing to the first element that has a greater value than given key
519 * or end() if no such element exists.
522 lower_bound(const key_type
& __x
) const { return _M_t
.lower_bound(__x
); }
525 * @brief Finds the end of a subsequence matching given key.
526 * @param x Key of (key, value) pair to be located.
527 * @return Iterator pointing to the first element
528 * greater than key, or end().
531 upper_bound(const key_type
& __x
) { return _M_t
.upper_bound(__x
); }
534 * @brief Finds the end of a subsequence matching given key.
535 * @param x Key of (key, value) pair to be located.
536 * @return Read-only (constant) iterator pointing to first iterator
537 * greater than key, or end().
540 upper_bound(const key_type
& __x
) const
541 { return _M_t
.upper_bound(__x
); }
544 * @brief Finds a subsequence matching given key.
545 * @param x Key of (key, value) pairs to be located.
546 * @return Pair of iterators that possibly points to the subsequence
547 * matching given key.
549 * This function is equivalent to
551 * std::make_pair(c.lower_bound(val),
552 * c.upper_bound(val))
554 * (but is faster than making the calls separately).
556 * This function probably only makes sense for multimaps.
558 pair
<iterator
,iterator
>
559 equal_range(const key_type
& __x
)
560 { return _M_t
.equal_range(__x
); }
563 * @brief Finds a subsequence matching given key.
564 * @param x Key of (key, value) pairs to be located.
565 * @return Pair of read-only (constant) iterators that possibly points to
566 * the subsequence matching given key.
568 * This function is equivalent to
570 * std::make_pair(c.lower_bound(val),
571 * c.upper_bound(val))
573 * (but is faster than making the calls separately).
575 * This function probably only makes sense for multimaps.
577 pair
<const_iterator
,const_iterator
>
578 equal_range(const key_type
& __x
) const
579 { return _M_t
.equal_range(__x
); }
581 template <typename _K1
, typename _T1
, typename _C1
, typename _A1
>
582 friend bool operator== (const map
<_K1
,_T1
,_C1
,_A1
>&,
583 const map
<_K1
,_T1
,_C1
,_A1
>&);
584 template <typename _K1
, typename _T1
, typename _C1
, typename _A1
>
585 friend bool operator< (const map
<_K1
,_T1
,_C1
,_A1
>&,
586 const map
<_K1
,_T1
,_C1
,_A1
>&);
591 * @brief Map equality comparison.
593 * @param y A %map of the same type as @a x.
594 * @return True iff the size and elements of the maps are equal.
596 * This is an equivalence relation. It is linear in the size of the
597 * maps. Maps are considered equivalent if their sizes are equal,
598 * and if corresponding elements compare equal.
600 template <typename _Key
, typename _Tp
, typename _Compare
, typename _Alloc
>
602 operator==(const map
<_Key
,_Tp
,_Compare
,_Alloc
>& __x
,
603 const map
<_Key
,_Tp
,_Compare
,_Alloc
>& __y
)
604 { return __x
._M_t
== __y
._M_t
; }
607 * @brief Map ordering relation.
609 * @param y A %map of the same type as @a x.
610 * @return True iff @a x is lexicographically less than @a y.
612 * This is a total ordering relation. It is linear in the size of the
613 * maps. The elements must be comparable with @c <.
615 * See std::lexicographical_compare() for how the determination is made.
617 template <typename _Key
, typename _Tp
, typename _Compare
, typename _Alloc
>
619 operator<(const map
<_Key
,_Tp
,_Compare
,_Alloc
>& __x
,
620 const map
<_Key
,_Tp
,_Compare
,_Alloc
>& __y
)
621 { return __x
._M_t
< __y
._M_t
; }
623 /// Based on operator==
624 template <typename _Key
, typename _Tp
, typename _Compare
, typename _Alloc
>
626 operator!=(const map
<_Key
,_Tp
,_Compare
,_Alloc
>& __x
,
627 const map
<_Key
,_Tp
,_Compare
,_Alloc
>& __y
)
628 { return !(__x
== __y
); }
630 /// Based on operator<
631 template <typename _Key
, typename _Tp
, typename _Compare
, typename _Alloc
>
633 operator>(const map
<_Key
,_Tp
,_Compare
,_Alloc
>& __x
,
634 const map
<_Key
,_Tp
,_Compare
,_Alloc
>& __y
)
635 { return __y
< __x
; }
637 /// Based on operator<
638 template <typename _Key
, typename _Tp
, typename _Compare
, typename _Alloc
>
640 operator<=(const map
<_Key
,_Tp
,_Compare
,_Alloc
>& __x
,
641 const map
<_Key
,_Tp
,_Compare
,_Alloc
>& __y
)
642 { return !(__y
< __x
); }
644 /// Based on operator<
645 template <typename _Key
, typename _Tp
, typename _Compare
, typename _Alloc
>
647 operator>=(const map
<_Key
,_Tp
,_Compare
,_Alloc
>& __x
,
648 const map
<_Key
,_Tp
,_Compare
,_Alloc
>& __y
)
649 { return !(__x
< __y
); }
651 /// See std::map::swap().
652 template <typename _Key
, typename _Tp
, typename _Compare
, typename _Alloc
>
654 swap(map
<_Key
,_Tp
,_Compare
,_Alloc
>& __x
, map
<_Key
,_Tp
,_Compare
,_Alloc
>& __y
)