1// Algorithm implementation -*- C++ -*-
2
3// Copyright (C) 2001-2019 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
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_algo.h
52 * This is an internal header file, included by other library headers.
53 * Do not attempt to use it directly. @headername{algorithm}
54 */
55
56#ifndef _STL_ALGO_H
57#define _STL_ALGO_H 1
58
59#include <cstdlib> // for rand
60#include <bits/algorithmfwd.h>
61#include <bits/stl_heap.h>
62#include <bits/stl_tempbuf.h> // for _Temporary_buffer
63#include <bits/predefined_ops.h>
64
65#if __cplusplus >= 201103L
66#include <bits/uniform_int_dist.h>
67#endif
68
69// See concept_check.h for the __glibcxx_*_requires macros.
70
71namespace std _GLIBCXX_VISIBILITY(default)
72{
73_GLIBCXX_BEGIN_NAMESPACE_VERSION
74
75 /// Swaps the median value of *__a, *__b and *__c under __comp to *__result
76 template<typename _Iterator, typename _Compare>
77 void
78 __move_median_to_first(_Iterator __result,_Iterator __a, _Iterator __b,
79 _Iterator __c, _Compare __comp)
80 {
81 if (__comp(__a, __b))
82 {
83 if (__comp(__b, __c))
84 std::iter_swap(__result, __b);
85 else if (__comp(__a, __c))
86 std::iter_swap(__result, __c);
87 else
88 std::iter_swap(__result, __a);
89 }
90 else if (__comp(__a, __c))
91 std::iter_swap(__result, __a);
92 else if (__comp(__b, __c))
93 std::iter_swap(__result, __c);
94 else
95 std::iter_swap(__result, __b);
96 }
97
98 /// This is an overload used by find algos for the Input Iterator case.
99 template<typename _InputIterator, typename _Predicate>
100 inline _InputIterator
101 __find_if(_InputIterator __first, _InputIterator __last,
102 _Predicate __pred, input_iterator_tag)
103 {
104 while (__first != __last && !__pred(__first))
105 ++__first;
106 return __first;
107 }
108
109 /// This is an overload used by find algos for the RAI case.
110 template<typename _RandomAccessIterator, typename _Predicate>
111 _RandomAccessIterator
112 __find_if(_RandomAccessIterator __first, _RandomAccessIterator __last,
113 _Predicate __pred, random_access_iterator_tag)
114 {
115 typename iterator_traits<_RandomAccessIterator>::difference_type
116 __trip_count = (__last - __first) >> 2;
117
118 for (; __trip_count > 0; --__trip_count)
119 {
120 if (__pred(__first))
121 return __first;
122 ++__first;
123
124 if (__pred(__first))
125 return __first;
126 ++__first;
127
128 if (__pred(__first))
129 return __first;
130 ++__first;
131
132 if (__pred(__first))
133 return __first;
134 ++__first;
135 }
136
137 switch (__last - __first)
138 {
139 case 3:
140 if (__pred(__first))
141 return __first;
142 ++__first;
143 case 2:
144 if (__pred(__first))
145 return __first;
146 ++__first;
147 case 1:
148 if (__pred(__first))
149 return __first;
150 ++__first;
151 case 0:
152 default:
153 return __last;
154 }
155 }
156
157 template<typename _Iterator, typename _Predicate>
158 inline _Iterator
159 __find_if(_Iterator __first, _Iterator __last, _Predicate __pred)
160 {
161 return __find_if(__first, __last, __pred,
162 std::__iterator_category(__first));
163 }
164
165 /// Provided for stable_partition to use.
166 template<typename _InputIterator, typename _Predicate>
167 inline _InputIterator
168 __find_if_not(_InputIterator __first, _InputIterator __last,
169 _Predicate __pred)
170 {
171 return std::__find_if(__first, __last,
172 __gnu_cxx::__ops::__negate(__pred),
173 std::__iterator_category(__first));
174 }
175
176 /// Like find_if_not(), but uses and updates a count of the
177 /// remaining range length instead of comparing against an end
178 /// iterator.
179 template<typename _InputIterator, typename _Predicate, typename _Distance>
180 _InputIterator
181 __find_if_not_n(_InputIterator __first, _Distance& __len, _Predicate __pred)
182 {
183 for (; __len; --__len, (void) ++__first)
184 if (!__pred(__first))
185 break;
186 return __first;
187 }
188
189 // set_difference
190 // set_intersection
191 // set_symmetric_difference
192 // set_union
193 // for_each
194 // find
195 // find_if
196 // find_first_of
197 // adjacent_find
198 // count
199 // count_if
200 // search
201
202 template<typename _ForwardIterator1, typename _ForwardIterator2,
203 typename _BinaryPredicate>
204 _ForwardIterator1
205 __search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
206 _ForwardIterator2 __first2, _ForwardIterator2 __last2,
207 _BinaryPredicate __predicate)
208 {
209 // Test for empty ranges
210 if (__first1 == __last1 || __first2 == __last2)
211 return __first1;
212
213 // Test for a pattern of length 1.
214 _ForwardIterator2 __p1(__first2);
215 if (++__p1 == __last2)
216 return std::__find_if(__first1, __last1,
217 __gnu_cxx::__ops::__iter_comp_iter(__predicate, __first2));
218
219 // General case.
220 _ForwardIterator2 __p;
221 _ForwardIterator1 __current = __first1;
222
223 for (;;)
224 {
225 __first1 =
226 std::__find_if(__first1, __last1,
227 __gnu_cxx::__ops::__iter_comp_iter(__predicate, __first2));
228
229 if (__first1 == __last1)
230 return __last1;
231
232 __p = __p1;
233 __current = __first1;
234 if (++__current == __last1)
235 return __last1;
236
237 while (__predicate(__current, __p))
238 {
239 if (++__p == __last2)
240 return __first1;
241 if (++__current == __last1)
242 return __last1;
243 }
244 ++__first1;
245 }
246 return __first1;
247 }
248
249 // search_n
250
251 /**
252 * This is an helper function for search_n overloaded for forward iterators.
253 */
254 template<typename _ForwardIterator, typename _Integer,
255 typename _UnaryPredicate>
256 _ForwardIterator
257 __search_n_aux(_ForwardIterator __first, _ForwardIterator __last,
258 _Integer __count, _UnaryPredicate __unary_pred,
259 std::forward_iterator_tag)
260 {
261 __first = std::__find_if(__first, __last, __unary_pred);
262 while (__first != __last)
263 {
264 typename iterator_traits<_ForwardIterator>::difference_type
265 __n = __count;
266 _ForwardIterator __i = __first;
267 ++__i;
268 while (__i != __last && __n != 1 && __unary_pred(__i))
269 {
270 ++__i;
271 --__n;
272 }
273 if (__n == 1)
274 return __first;
275 if (__i == __last)
276 return __last;
277 __first = std::__find_if(++__i, __last, __unary_pred);
278 }
279 return __last;
280 }
281
282 /**
283 * This is an helper function for search_n overloaded for random access
284 * iterators.
285 */
286 template<typename _RandomAccessIter, typename _Integer,
287 typename _UnaryPredicate>
288 _RandomAccessIter
289 __search_n_aux(_RandomAccessIter __first, _RandomAccessIter __last,
290 _Integer __count, _UnaryPredicate __unary_pred,
291 std::random_access_iterator_tag)
292 {
293 typedef typename std::iterator_traits<_RandomAccessIter>::difference_type
294 _DistanceType;
295
296 _DistanceType __tailSize = __last - __first;
297 _DistanceType __remainder = __count;
298
299 while (__remainder <= __tailSize) // the main loop...
300 {
301 __first += __remainder;
302 __tailSize -= __remainder;
303 // __first here is always pointing to one past the last element of
304 // next possible match.
305 _RandomAccessIter __backTrack = __first;
306 while (__unary_pred(--__backTrack))
307 {
308 if (--__remainder == 0)
309 return (__first - __count); // Success
310 }
311 __remainder = __count + 1 - (__first - __backTrack);
312 }
313 return __last; // Failure
314 }
315
316 template<typename _ForwardIterator, typename _Integer,
317 typename _UnaryPredicate>
318 _ForwardIterator
319 __search_n(_ForwardIterator __first, _ForwardIterator __last,
320 _Integer __count,
321 _UnaryPredicate __unary_pred)
322 {
323 if (__count <= 0)
324 return __first;
325
326 if (__count == 1)
327 return std::__find_if(__first, __last, __unary_pred);
328
329 return std::__search_n_aux(__first, __last, __count, __unary_pred,
330 std::__iterator_category(__first));
331 }
332
333 // find_end for forward iterators.
334 template<typename _ForwardIterator1, typename _ForwardIterator2,
335 typename _BinaryPredicate>
336 _ForwardIterator1
337 __find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
338 _ForwardIterator2 __first2, _ForwardIterator2 __last2,
339 forward_iterator_tag, forward_iterator_tag,
340 _BinaryPredicate __comp)
341 {
342 if (__first2 == __last2)
343 return __last1;
344
345 _ForwardIterator1 __result = __last1;
346 while (1)
347 {
348 _ForwardIterator1 __new_result
349 = std::__search(__first1, __last1, __first2, __last2, __comp);
350 if (__new_result == __last1)
351 return __result;
352 else
353 {
354 __result = __new_result;
355 __first1 = __new_result;
356 ++__first1;
357 }
358 }
359 }
360
361 // find_end for bidirectional iterators (much faster).
362 template<typename _BidirectionalIterator1, typename _BidirectionalIterator2,
363 typename _BinaryPredicate>
364 _BidirectionalIterator1
365 __find_end(_BidirectionalIterator1 __first1,
366 _BidirectionalIterator1 __last1,
367 _BidirectionalIterator2 __first2,
368 _BidirectionalIterator2 __last2,
369 bidirectional_iterator_tag, bidirectional_iterator_tag,
370 _BinaryPredicate __comp)
371 {
372 // concept requirements
373 __glibcxx_function_requires(_BidirectionalIteratorConcept<
374 _BidirectionalIterator1>)
375 __glibcxx_function_requires(_BidirectionalIteratorConcept<
376 _BidirectionalIterator2>)
377
378 typedef reverse_iterator<_BidirectionalIterator1> _RevIterator1;
379 typedef reverse_iterator<_BidirectionalIterator2> _RevIterator2;
380
381 _RevIterator1 __rlast1(__first1);
382 _RevIterator2 __rlast2(__first2);
383 _RevIterator1 __rresult = std::__search(_RevIterator1(__last1), __rlast1,
384 _RevIterator2(__last2), __rlast2,
385 __comp);
386
387 if (__rresult == __rlast1)
388 return __last1;
389 else
390 {
391 _BidirectionalIterator1 __result = __rresult.base();
392 std::advance(__result, -std::distance(__first2, __last2));
393 return __result;
394 }
395 }
396
397 /**
398 * @brief Find last matching subsequence in a sequence.
399 * @ingroup non_mutating_algorithms
400 * @param __first1 Start of range to search.
401 * @param __last1 End of range to search.
402 * @param __first2 Start of sequence to match.
403 * @param __last2 End of sequence to match.
404 * @return The last iterator @c i in the range
405 * @p [__first1,__last1-(__last2-__first2)) such that @c *(i+N) ==
406 * @p *(__first2+N) for each @c N in the range @p
407 * [0,__last2-__first2), or @p __last1 if no such iterator exists.
408 *
409 * Searches the range @p [__first1,__last1) for a sub-sequence that
410 * compares equal value-by-value with the sequence given by @p
411 * [__first2,__last2) and returns an iterator to the __first
412 * element of the sub-sequence, or @p __last1 if the sub-sequence
413 * is not found. The sub-sequence will be the last such
414 * subsequence contained in [__first1,__last1).
415 *
416 * Because the sub-sequence must lie completely within the range @p
417 * [__first1,__last1) it must start at a position less than @p
418 * __last1-(__last2-__first2) where @p __last2-__first2 is the
419 * length of the sub-sequence. This means that the returned
420 * iterator @c i will be in the range @p
421 * [__first1,__last1-(__last2-__first2))
422 */
423 template<typename _ForwardIterator1, typename _ForwardIterator2>
424 inline _ForwardIterator1
425 find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
426 _ForwardIterator2 __first2, _ForwardIterator2 __last2)
427 {
428 // concept requirements
429 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
430 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
431 __glibcxx_function_requires(_EqualOpConcept<
432 typename iterator_traits<_ForwardIterator1>::value_type,
433 typename iterator_traits<_ForwardIterator2>::value_type>)
434 __glibcxx_requires_valid_range(__first1, __last1);
435 __glibcxx_requires_valid_range(__first2, __last2);
436
437 return std::__find_end(__first1, __last1, __first2, __last2,
438 std::__iterator_category(__first1),
439 std::__iterator_category(__first2),
440 __gnu_cxx::__ops::__iter_equal_to_iter());
441 }
442
443 /**
444 * @brief Find last matching subsequence in a sequence using a predicate.
445 * @ingroup non_mutating_algorithms
446 * @param __first1 Start of range to search.
447 * @param __last1 End of range to search.
448 * @param __first2 Start of sequence to match.
449 * @param __last2 End of sequence to match.
450 * @param __comp The predicate to use.
451 * @return The last iterator @c i in the range @p
452 * [__first1,__last1-(__last2-__first2)) such that @c
453 * predicate(*(i+N), @p (__first2+N)) is true for each @c N in the
454 * range @p [0,__last2-__first2), or @p __last1 if no such iterator
455 * exists.
456 *
457 * Searches the range @p [__first1,__last1) for a sub-sequence that
458 * compares equal value-by-value with the sequence given by @p
459 * [__first2,__last2) using comp as a predicate and returns an
460 * iterator to the first element of the sub-sequence, or @p __last1
461 * if the sub-sequence is not found. The sub-sequence will be the
462 * last such subsequence contained in [__first,__last1).
463 *
464 * Because the sub-sequence must lie completely within the range @p
465 * [__first1,__last1) it must start at a position less than @p
466 * __last1-(__last2-__first2) where @p __last2-__first2 is the
467 * length of the sub-sequence. This means that the returned
468 * iterator @c i will be in the range @p
469 * [__first1,__last1-(__last2-__first2))
470 */
471 template<typename _ForwardIterator1, typename _ForwardIterator2,
472 typename _BinaryPredicate>
473 inline _ForwardIterator1
474 find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
475 _ForwardIterator2 __first2, _ForwardIterator2 __last2,
476 _BinaryPredicate __comp)
477 {
478 // concept requirements
479 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
480 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
481 __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
482 typename iterator_traits<_ForwardIterator1>::value_type,
483 typename iterator_traits<_ForwardIterator2>::value_type>)
484 __glibcxx_requires_valid_range(__first1, __last1);
485 __glibcxx_requires_valid_range(__first2, __last2);
486
487 return std::__find_end(__first1, __last1, __first2, __last2,
488 std::__iterator_category(__first1),
489 std::__iterator_category(__first2),
490 __gnu_cxx::__ops::__iter_comp_iter(__comp));
491 }
492
493#if __cplusplus >= 201103L
494 /**
495 * @brief Checks that a predicate is true for all the elements
496 * of a sequence.
497 * @ingroup non_mutating_algorithms
498 * @param __first An input iterator.
499 * @param __last An input iterator.
500 * @param __pred A predicate.
501 * @return True if the check is true, false otherwise.
502 *
503 * Returns true if @p __pred is true for each element in the range
504 * @p [__first,__last), and false otherwise.
505 */
506 template<typename _InputIterator, typename _Predicate>
507 inline bool
508 all_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)
509 { return __last == std::find_if_not(__first, __last, __pred); }
510
511 /**
512 * @brief Checks that a predicate is false for all the elements
513 * of a sequence.
514 * @ingroup non_mutating_algorithms
515 * @param __first An input iterator.
516 * @param __last An input iterator.
517 * @param __pred A predicate.
518 * @return True if the check is true, false otherwise.
519 *
520 * Returns true if @p __pred is false for each element in the range
521 * @p [__first,__last), and false otherwise.
522 */
523 template<typename _InputIterator, typename _Predicate>
524 inline bool
525 none_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)
526 { return __last == _GLIBCXX_STD_A::find_if(__first, __last, __pred); }
527
528 /**
529 * @brief Checks that a predicate is true for at least one element
530 * of a sequence.
531 * @ingroup non_mutating_algorithms
532 * @param __first An input iterator.
533 * @param __last An input iterator.
534 * @param __pred A predicate.
535 * @return True if the check is true, false otherwise.
536 *
537 * Returns true if an element exists in the range @p
538 * [__first,__last) such that @p __pred is true, and false
539 * otherwise.
540 */
541 template<typename _InputIterator, typename _Predicate>
542 inline bool
543 any_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)
544 { return !std::none_of(__first, __last, __pred); }
545
546 /**
547 * @brief Find the first element in a sequence for which a
548 * predicate is false.
549 * @ingroup non_mutating_algorithms
550 * @param __first An input iterator.
551 * @param __last An input iterator.
552 * @param __pred A predicate.
553 * @return The first iterator @c i in the range @p [__first,__last)
554 * such that @p __pred(*i) is false, or @p __last if no such iterator exists.
555 */
556 template<typename _InputIterator, typename _Predicate>
557 inline _InputIterator
558 find_if_not(_InputIterator __first, _InputIterator __last,
559 _Predicate __pred)
560 {
561 // concept requirements
562 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
563 __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
564 typename iterator_traits<_InputIterator>::value_type>)
565 __glibcxx_requires_valid_range(__first, __last);
566 return std::__find_if_not(__first, __last,
567 __gnu_cxx::__ops::__pred_iter(__pred));
568 }
569
570 /**
571 * @brief Checks whether the sequence is partitioned.
572 * @ingroup mutating_algorithms
573 * @param __first An input iterator.
574 * @param __last An input iterator.
575 * @param __pred A predicate.
576 * @return True if the range @p [__first,__last) is partioned by @p __pred,
577 * i.e. if all elements that satisfy @p __pred appear before those that
578 * do not.
579 */
580 template<typename _InputIterator, typename _Predicate>
581 inline bool
582 is_partitioned(_InputIterator __first, _InputIterator __last,
583 _Predicate __pred)
584 {
585 __first = std::find_if_not(__first, __last, __pred);
586 if (__first == __last)
587 return true;
588 ++__first;
589 return std::none_of(__first, __last, __pred);
590 }
591
592 /**
593 * @brief Find the partition point of a partitioned range.
594 * @ingroup mutating_algorithms
595 * @param __first An iterator.
596 * @param __last Another iterator.
597 * @param __pred A predicate.
598 * @return An iterator @p mid such that @p all_of(__first, mid, __pred)
599 * and @p none_of(mid, __last, __pred) are both true.
600 */
601 template<typename _ForwardIterator, typename _Predicate>
602 _ForwardIterator
603 partition_point(_ForwardIterator __first, _ForwardIterator __last,
604 _Predicate __pred)
605 {
606 // concept requirements
607 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
608 __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
609 typename iterator_traits<_ForwardIterator>::value_type>)
610
611 // A specific debug-mode test will be necessary...
612 __glibcxx_requires_valid_range(__first, __last);
613
614 typedef typename iterator_traits<_ForwardIterator>::difference_type
615 _DistanceType;
616
617 _DistanceType __len = std::distance(__first, __last);
618 _DistanceType __half;
619 _ForwardIterator __middle;
620
621 while (__len > 0)
622 {
623 __half = __len >> 1;
624 __middle = __first;
625 std::advance(__middle, __half);
626 if (__pred(*__middle))
627 {
628 __first = __middle;
629 ++__first;
630 __len = __len - __half - 1;
631 }
632 else
633 __len = __half;
634 }
635 return __first;
636 }
637#endif
638
639 template<typename _InputIterator, typename _OutputIterator,
640 typename _Predicate>
641 _OutputIterator
642 __remove_copy_if(_InputIterator __first, _InputIterator __last,
643 _OutputIterator __result, _Predicate __pred)
644 {
645 for (; __first != __last; ++__first)
646 if (!__pred(__first))
647 {
648 *__result = *__first;
649 ++__result;
650 }
651 return __result;
652 }
653
654 /**
655 * @brief Copy a sequence, removing elements of a given value.
656 * @ingroup mutating_algorithms
657 * @param __first An input iterator.
658 * @param __last An input iterator.
659 * @param __result An output iterator.
660 * @param __value The value to be removed.
661 * @return An iterator designating the end of the resulting sequence.
662 *
663 * Copies each element in the range @p [__first,__last) not equal
664 * to @p __value to the range beginning at @p __result.
665 * remove_copy() is stable, so the relative order of elements that
666 * are copied is unchanged.
667 */
668 template<typename _InputIterator, typename _OutputIterator, typename _Tp>
669 inline _OutputIterator
670 remove_copy(_InputIterator __first, _InputIterator __last,
671 _OutputIterator __result, const _Tp& __value)
672 {
673 // concept requirements
674 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
675 __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
676 typename iterator_traits<_InputIterator>::value_type>)
677 __glibcxx_function_requires(_EqualOpConcept<
678 typename iterator_traits<_InputIterator>::value_type, _Tp>)
679 __glibcxx_requires_valid_range(__first, __last);
680
681 return std::__remove_copy_if(__first, __last, __result,
682 __gnu_cxx::__ops::__iter_equals_val(__value));
683 }
684
685 /**
686 * @brief Copy a sequence, removing elements for which a predicate is true.
687 * @ingroup mutating_algorithms
688 * @param __first An input iterator.
689 * @param __last An input iterator.
690 * @param __result An output iterator.
691 * @param __pred A predicate.
692 * @return An iterator designating the end of the resulting sequence.
693 *
694 * Copies each element in the range @p [__first,__last) for which
695 * @p __pred returns false to the range beginning at @p __result.
696 *
697 * remove_copy_if() is stable, so the relative order of elements that are
698 * copied is unchanged.
699 */
700 template<typename _InputIterator, typename _OutputIterator,
701 typename _Predicate>
702 inline _OutputIterator
703 remove_copy_if(_InputIterator __first, _InputIterator __last,
704 _OutputIterator __result, _Predicate __pred)
705 {
706 // concept requirements
707 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
708 __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
709 typename iterator_traits<_InputIterator>::value_type>)
710 __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
711 typename iterator_traits<_InputIterator>::value_type>)
712 __glibcxx_requires_valid_range(__first, __last);
713
714 return std::__remove_copy_if(__first, __last, __result,
715 __gnu_cxx::__ops::__pred_iter(__pred));
716 }
717
718#if __cplusplus >= 201103L
719 /**
720 * @brief Copy the elements of a sequence for which a predicate is true.
721 * @ingroup mutating_algorithms
722 * @param __first An input iterator.
723 * @param __last An input iterator.
724 * @param __result An output iterator.
725 * @param __pred A predicate.
726 * @return An iterator designating the end of the resulting sequence.
727 *
728 * Copies each element in the range @p [__first,__last) for which
729 * @p __pred returns true to the range beginning at @p __result.
730 *
731 * copy_if() is stable, so the relative order of elements that are
732 * copied is unchanged.
733 */
734 template<typename _InputIterator, typename _OutputIterator,
735 typename _Predicate>
736 _OutputIterator
737 copy_if(_InputIterator __first, _InputIterator __last,
738 _OutputIterator __result, _Predicate __pred)
739 {
740 // concept requirements
741 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
742 __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
743 typename iterator_traits<_InputIterator>::value_type>)
744 __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
745 typename iterator_traits<_InputIterator>::value_type>)
746 __glibcxx_requires_valid_range(__first, __last);
747
748 for (; __first != __last; ++__first)
749 if (__pred(*__first))
750 {
751 *__result = *__first;
752 ++__result;
753 }
754 return __result;
755 }
756
757 template<typename _InputIterator, typename _Size, typename _OutputIterator>
758 _OutputIterator
759 __copy_n(_InputIterator __first, _Size __n,
760 _OutputIterator __result, input_iterator_tag)
761 {
762 if (__n > 0)
763 {
764 while (true)
765 {
766 *__result = *__first;
767 ++__result;
768 if (--__n > 0)
769 ++__first;
770 else
771 break;
772 }
773 }
774 return __result;
775 }
776
777 template<typename _RandomAccessIterator, typename _Size,
778 typename _OutputIterator>
779 inline _OutputIterator
780 __copy_n(_RandomAccessIterator __first, _Size __n,
781 _OutputIterator __result, random_access_iterator_tag)
782 { return std::copy(__first, __first + __n, __result); }
783
784 /**
785 * @brief Copies the range [first,first+n) into [result,result+n).
786 * @ingroup mutating_algorithms
787 * @param __first An input iterator.
788 * @param __n The number of elements to copy.
789 * @param __result An output iterator.
790 * @return result+n.
791 *
792 * This inline function will boil down to a call to @c memmove whenever
793 * possible. Failing that, if random access iterators are passed, then the
794 * loop count will be known (and therefore a candidate for compiler
795 * optimizations such as unrolling).
796 */
797 template<typename _InputIterator, typename _Size, typename _OutputIterator>
798 inline _OutputIterator
799 copy_n(_InputIterator __first, _Size __n, _OutputIterator __result)
800 {
801 // concept requirements
802 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
803 __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
804 typename iterator_traits<_InputIterator>::value_type>)
805
806 if (__n <= 0)
807 return __result;
808
809 __glibcxx_requires_can_increment(__first, __n);
810 __glibcxx_requires_can_increment(__result, __n);
811
812 return std::__copy_n(__first, __n, __result,
813 std::__iterator_category(__first));
814 }
815
816 /**
817 * @brief Copy the elements of a sequence to separate output sequences
818 * depending on the truth value of a predicate.
819 * @ingroup mutating_algorithms
820 * @param __first An input iterator.
821 * @param __last An input iterator.
822 * @param __out_true An output iterator.
823 * @param __out_false An output iterator.
824 * @param __pred A predicate.
825 * @return A pair designating the ends of the resulting sequences.
826 *
827 * Copies each element in the range @p [__first,__last) for which
828 * @p __pred returns true to the range beginning at @p out_true
829 * and each element for which @p __pred returns false to @p __out_false.
830 */
831 template<typename _InputIterator, typename _OutputIterator1,
832 typename _OutputIterator2, typename _Predicate>
833 pair<_OutputIterator1, _OutputIterator2>
834 partition_copy(_InputIterator __first, _InputIterator __last,
835 _OutputIterator1 __out_true, _OutputIterator2 __out_false,
836 _Predicate __pred)
837 {
838 // concept requirements
839 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
840 __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator1,
841 typename iterator_traits<_InputIterator>::value_type>)
842 __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator2,
843 typename iterator_traits<_InputIterator>::value_type>)
844 __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
845 typename iterator_traits<_InputIterator>::value_type>)
846 __glibcxx_requires_valid_range(__first, __last);
847
848 for (; __first != __last; ++__first)
849 if (__pred(*__first))
850 {
851 *__out_true = *__first;
852 ++__out_true;
853 }
854 else
855 {
856 *__out_false = *__first;
857 ++__out_false;
858 }
859
860 return pair<_OutputIterator1, _OutputIterator2>(__out_true, __out_false);
861 }
862#endif
863
864 template<typename _ForwardIterator, typename _Predicate>
865 _ForwardIterator
866 __remove_if(_ForwardIterator __first, _ForwardIterator __last,
867 _Predicate __pred)
868 {
869 __first = std::__find_if(__first, __last, __pred);
870 if (__first == __last)
871 return __first;
872 _ForwardIterator __result = __first;
873 ++__first;
874 for (; __first != __last; ++__first)
875 if (!__pred(__first))
876 {
877 *__result = _GLIBCXX_MOVE(*__first);
878 ++__result;
879 }
880 return __result;
881 }
882
883 /**
884 * @brief Remove elements from a sequence.
885 * @ingroup mutating_algorithms
886 * @param __first An input iterator.
887 * @param __last An input iterator.
888 * @param __value The value to be removed.
889 * @return An iterator designating the end of the resulting sequence.
890 *
891 * All elements equal to @p __value are removed from the range
892 * @p [__first,__last).
893 *
894 * remove() is stable, so the relative order of elements that are
895 * not removed is unchanged.
896 *
897 * Elements between the end of the resulting sequence and @p __last
898 * are still present, but their value is unspecified.
899 */
900 template<typename _ForwardIterator, typename _Tp>
901 inline _ForwardIterator
902 remove(_ForwardIterator __first, _ForwardIterator __last,
903 const _Tp& __value)
904 {
905 // concept requirements
906 __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
907 _ForwardIterator>)
908 __glibcxx_function_requires(_EqualOpConcept<
909 typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
910 __glibcxx_requires_valid_range(__first, __last);
911
912 return std::__remove_if(__first, __last,
913 __gnu_cxx::__ops::__iter_equals_val(__value));
914 }
915
916 /**
917 * @brief Remove elements from a sequence using a predicate.
918 * @ingroup mutating_algorithms
919 * @param __first A forward iterator.
920 * @param __last A forward iterator.
921 * @param __pred A predicate.
922 * @return An iterator designating the end of the resulting sequence.
923 *
924 * All elements for which @p __pred returns true are removed from the range
925 * @p [__first,__last).
926 *
927 * remove_if() is stable, so the relative order of elements that are
928 * not removed is unchanged.
929 *
930 * Elements between the end of the resulting sequence and @p __last
931 * are still present, but their value is unspecified.
932 */
933 template<typename _ForwardIterator, typename _Predicate>
934 inline _ForwardIterator
935 remove_if(_ForwardIterator __first, _ForwardIterator __last,
936 _Predicate __pred)
937 {
938 // concept requirements
939 __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
940 _ForwardIterator>)
941 __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
942 typename iterator_traits<_ForwardIterator>::value_type>)
943 __glibcxx_requires_valid_range(__first, __last);
944
945 return std::__remove_if(__first, __last,
946 __gnu_cxx::__ops::__pred_iter(__pred));
947 }
948
949 template<typename _ForwardIterator, typename _BinaryPredicate>
950 _ForwardIterator
951 __adjacent_find(_ForwardIterator __first, _ForwardIterator __last,
952 _BinaryPredicate __binary_pred)
953 {
954 if (__first == __last)
955 return __last;
956 _ForwardIterator __next = __first;
957 while (++__next != __last)
958 {
959 if (__binary_pred(__first, __next))
960 return __first;
961 __first = __next;
962 }
963 return __last;
964 }
965
966 template<typename _ForwardIterator, typename _BinaryPredicate>
967 _ForwardIterator
968 __unique(_ForwardIterator __first, _ForwardIterator __last,
969 _BinaryPredicate __binary_pred)
970 {
971 // Skip the beginning, if already unique.
972 __first = std::__adjacent_find(__first, __last, __binary_pred);
973 if (__first == __last)
974 return __last;
975
976 // Do the real copy work.
977 _ForwardIterator __dest = __first;
978 ++__first;
979 while (++__first != __last)
980 if (!__binary_pred(__dest, __first))
981 *++__dest = _GLIBCXX_MOVE(*__first);
982 return ++__dest;
983 }
984
985 /**
986 * @brief Remove consecutive duplicate values from a sequence.
987 * @ingroup mutating_algorithms
988 * @param __first A forward iterator.
989 * @param __last A forward iterator.
990 * @return An iterator designating the end of the resulting sequence.
991 *
992 * Removes all but the first element from each group of consecutive
993 * values that compare equal.
994 * unique() is stable, so the relative order of elements that are
995 * not removed is unchanged.
996 * Elements between the end of the resulting sequence and @p __last
997 * are still present, but their value is unspecified.
998 */
999 template<typename _ForwardIterator>
1000 inline _ForwardIterator
1001 unique(_ForwardIterator __first, _ForwardIterator __last)
1002 {
1003 // concept requirements
1004 __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
1005 _ForwardIterator>)
1006 __glibcxx_function_requires(_EqualityComparableConcept<
1007 typename iterator_traits<_ForwardIterator>::value_type>)
1008 __glibcxx_requires_valid_range(__first, __last);
1009
1010 return std::__unique(__first, __last,
1011 __gnu_cxx::__ops::__iter_equal_to_iter());
1012 }
1013
1014 /**
1015 * @brief Remove consecutive values from a sequence using a predicate.
1016 * @ingroup mutating_algorithms
1017 * @param __first A forward iterator.
1018 * @param __last A forward iterator.
1019 * @param __binary_pred A binary predicate.
1020 * @return An iterator designating the end of the resulting sequence.
1021 *
1022 * Removes all but the first element from each group of consecutive
1023 * values for which @p __binary_pred returns true.
1024 * unique() is stable, so the relative order of elements that are
1025 * not removed is unchanged.
1026 * Elements between the end of the resulting sequence and @p __last
1027 * are still present, but their value is unspecified.
1028 */
1029 template<typename _ForwardIterator, typename _BinaryPredicate>
1030 inline _ForwardIterator
1031 unique(_ForwardIterator __first, _ForwardIterator __last,
1032 _BinaryPredicate __binary_pred)
1033 {
1034 // concept requirements
1035 __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
1036 _ForwardIterator>)
1037 __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
1038 typename iterator_traits<_ForwardIterator>::value_type,
1039 typename iterator_traits<_ForwardIterator>::value_type>)
1040 __glibcxx_requires_valid_range(__first, __last);
1041
1042 return std::__unique(__first, __last,
1043 __gnu_cxx::__ops::__iter_comp_iter(__binary_pred));
1044 }
1045
1046 /**
1047 * This is an uglified
1048 * unique_copy(_InputIterator, _InputIterator, _OutputIterator,
1049 * _BinaryPredicate)
1050 * overloaded for forward iterators and output iterator as result.
1051 */
1052 template<typename _ForwardIterator, typename _OutputIterator,
1053 typename _BinaryPredicate>
1054 _OutputIterator
1055 __unique_copy(_ForwardIterator __first, _ForwardIterator __last,
1056 _OutputIterator __result, _BinaryPredicate __binary_pred,
1057 forward_iterator_tag, output_iterator_tag)
1058 {
1059 // concept requirements -- iterators already checked
1060 __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
1061 typename iterator_traits<_ForwardIterator>::value_type,
1062 typename iterator_traits<_ForwardIterator>::value_type>)
1063
1064 _ForwardIterator __next = __first;
1065 *__result = *__first;
1066 while (++__next != __last)
1067 if (!__binary_pred(__first, __next))
1068 {
1069 __first = __next;
1070 *++__result = *__first;
1071 }
1072 return ++__result;
1073 }
1074
1075 /**
1076 * This is an uglified
1077 * unique_copy(_InputIterator, _InputIterator, _OutputIterator,
1078 * _BinaryPredicate)
1079 * overloaded for input iterators and output iterator as result.
1080 */
1081 template<typename _InputIterator, typename _OutputIterator,
1082 typename _BinaryPredicate>
1083 _OutputIterator
1084 __unique_copy(_InputIterator __first, _InputIterator __last,
1085 _OutputIterator __result, _BinaryPredicate __binary_pred,
1086 input_iterator_tag, output_iterator_tag)
1087 {
1088 // concept requirements -- iterators already checked
1089 __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
1090 typename iterator_traits<_InputIterator>::value_type,
1091 typename iterator_traits<_InputIterator>::value_type>)
1092
1093 typename iterator_traits<_InputIterator>::value_type __value = *__first;
1094 __decltype(__gnu_cxx::__ops::__iter_comp_val(__binary_pred))
1095 __rebound_pred
1096 = __gnu_cxx::__ops::__iter_comp_val(__binary_pred);
1097 *__result = __value;
1098 while (++__first != __last)
1099 if (!__rebound_pred(__first, __value))
1100 {
1101 __value = *__first;
1102 *++__result = __value;
1103 }
1104 return ++__result;
1105 }
1106
1107 /**
1108 * This is an uglified
1109 * unique_copy(_InputIterator, _InputIterator, _OutputIterator,
1110 * _BinaryPredicate)
1111 * overloaded for input iterators and forward iterator as result.
1112 */
1113 template<typename _InputIterator, typename _ForwardIterator,
1114 typename _BinaryPredicate>
1115 _ForwardIterator
1116 __unique_copy(_InputIterator __first, _InputIterator __last,
1117 _ForwardIterator __result, _BinaryPredicate __binary_pred,
1118 input_iterator_tag, forward_iterator_tag)
1119 {
1120 // concept requirements -- iterators already checked
1121 __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
1122 typename iterator_traits<_ForwardIterator>::value_type,
1123 typename iterator_traits<_InputIterator>::value_type>)
1124 *__result = *__first;
1125 while (++__first != __last)
1126 if (!__binary_pred(__result, __first))
1127 *++__result = *__first;
1128 return ++__result;
1129 }
1130
1131 /**
1132 * This is an uglified reverse(_BidirectionalIterator,
1133 * _BidirectionalIterator)
1134 * overloaded for bidirectional iterators.
1135 */
1136 template<typename _BidirectionalIterator>
1137 void
1138 __reverse(_BidirectionalIterator __first, _BidirectionalIterator __last,
1139 bidirectional_iterator_tag)
1140 {
1141 while (true)
1142 if (__first == __last || __first == --__last)
1143 return;
1144 else
1145 {
1146 std::iter_swap(__first, __last);
1147 ++__first;
1148 }
1149 }
1150
1151 /**
1152 * This is an uglified reverse(_BidirectionalIterator,
1153 * _BidirectionalIterator)
1154 * overloaded for random access iterators.
1155 */
1156 template<typename _RandomAccessIterator>
1157 void
1158 __reverse(_RandomAccessIterator __first, _RandomAccessIterator __last,
1159 random_access_iterator_tag)
1160 {
1161 if (__first == __last)
1162 return;
1163 --__last;
1164 while (__first < __last)
1165 {
1166 std::iter_swap(__first, __last);
1167 ++__first;
1168 --__last;
1169 }
1170 }
1171
1172 /**
1173 * @brief Reverse a sequence.
1174 * @ingroup mutating_algorithms
1175 * @param __first A bidirectional iterator.
1176 * @param __last A bidirectional iterator.
1177 * @return reverse() returns no value.
1178 *
1179 * Reverses the order of the elements in the range @p [__first,__last),
1180 * so that the first element becomes the last etc.
1181 * For every @c i such that @p 0<=i<=(__last-__first)/2), @p reverse()
1182 * swaps @p *(__first+i) and @p *(__last-(i+1))
1183 */
1184 template<typename _BidirectionalIterator>
1185 inline void
1186 reverse(_BidirectionalIterator __first, _BidirectionalIterator __last)
1187 {
1188 // concept requirements
1189 __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<
1190 _BidirectionalIterator>)
1191 __glibcxx_requires_valid_range(__first, __last);
1192 std::__reverse(__first, __last, std::__iterator_category(__first));
1193 }
1194
1195 /**
1196 * @brief Copy a sequence, reversing its elements.
1197 * @ingroup mutating_algorithms
1198 * @param __first A bidirectional iterator.
1199 * @param __last A bidirectional iterator.
1200 * @param __result An output iterator.
1201 * @return An iterator designating the end of the resulting sequence.
1202 *
1203 * Copies the elements in the range @p [__first,__last) to the
1204 * range @p [__result,__result+(__last-__first)) such that the
1205 * order of the elements is reversed. For every @c i such that @p
1206 * 0<=i<=(__last-__first), @p reverse_copy() performs the
1207 * assignment @p *(__result+(__last-__first)-1-i) = *(__first+i).
1208 * The ranges @p [__first,__last) and @p
1209 * [__result,__result+(__last-__first)) must not overlap.
1210 */
1211 template<typename _BidirectionalIterator, typename _OutputIterator>
1212 _OutputIterator
1213 reverse_copy(_BidirectionalIterator __first, _BidirectionalIterator __last,
1214 _OutputIterator __result)
1215 {
1216 // concept requirements
1217 __glibcxx_function_requires(_BidirectionalIteratorConcept<
1218 _BidirectionalIterator>)
1219 __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
1220 typename iterator_traits<_BidirectionalIterator>::value_type>)
1221 __glibcxx_requires_valid_range(__first, __last);
1222
1223 while (__first != __last)
1224 {
1225 --__last;
1226 *__result = *__last;
1227 ++__result;
1228 }
1229 return __result;
1230 }
1231
1232 /**
1233 * This is a helper function for the rotate algorithm specialized on RAIs.
1234 * It returns the greatest common divisor of two integer values.
1235 */
1236 template<typename _EuclideanRingElement>
1237 _EuclideanRingElement
1238 __gcd(_EuclideanRingElement __m, _EuclideanRingElement __n)
1239 {
1240 while (__n != 0)
1241 {
1242 _EuclideanRingElement __t = __m % __n;
1243 __m = __n;
1244 __n = __t;
1245 }
1246 return __m;
1247 }
1248
1249 inline namespace _V2
1250 {
1251
1252 /// This is a helper function for the rotate algorithm.
1253 template<typename _ForwardIterator>
1254 _ForwardIterator
1255 __rotate(_ForwardIterator __first,
1256 _ForwardIterator __middle,
1257 _ForwardIterator __last,
1258 forward_iterator_tag)
1259 {
1260 if (__first == __middle)
1261 return __last;
1262 else if (__last == __middle)
1263 return __first;
1264
1265 _ForwardIterator __first2 = __middle;
1266 do
1267 {
1268 std::iter_swap(__first, __first2);
1269 ++__first;
1270 ++__first2;
1271 if (__first == __middle)
1272 __middle = __first2;
1273 }
1274 while (__first2 != __last);
1275
1276 _ForwardIterator __ret = __first;
1277
1278 __first2 = __middle;
1279
1280 while (__first2 != __last)
1281 {
1282 std::iter_swap(__first, __first2);
1283 ++__first;
1284 ++__first2;
1285 if (__first == __middle)
1286 __middle = __first2;
1287 else if (__first2 == __last)
1288 __first2 = __middle;
1289 }
1290 return __ret;
1291 }
1292
1293 /// This is a helper function for the rotate algorithm.
1294 template<typename _BidirectionalIterator>
1295 _BidirectionalIterator
1296 __rotate(_BidirectionalIterator __first,
1297 _BidirectionalIterator __middle,
1298 _BidirectionalIterator __last,
1299 bidirectional_iterator_tag)
1300 {
1301 // concept requirements
1302 __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<
1303 _BidirectionalIterator>)
1304
1305 if (__first == __middle)
1306 return __last;
1307 else if (__last == __middle)
1308 return __first;
1309
1310 std::__reverse(__first, __middle, bidirectional_iterator_tag());
1311 std::__reverse(__middle, __last, bidirectional_iterator_tag());
1312
1313 while (__first != __middle && __middle != __last)
1314 {
1315 std::iter_swap(__first, --__last);
1316 ++__first;
1317 }
1318
1319 if (__first == __middle)
1320 {
1321 std::__reverse(__middle, __last, bidirectional_iterator_tag());
1322 return __last;
1323 }
1324 else
1325 {
1326 std::__reverse(__first, __middle, bidirectional_iterator_tag());
1327 return __first;
1328 }
1329 }
1330
1331 /// This is a helper function for the rotate algorithm.
1332 template<typename _RandomAccessIterator>
1333 _RandomAccessIterator
1334 __rotate(_RandomAccessIterator __first,
1335 _RandomAccessIterator __middle,
1336 _RandomAccessIterator __last,
1337 random_access_iterator_tag)
1338 {
1339 // concept requirements
1340 __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
1341 _RandomAccessIterator>)
1342
1343 if (__first == __middle)
1344 return __last;
1345 else if (__last == __middle)
1346 return __first;
1347
1348 typedef typename iterator_traits<_RandomAccessIterator>::difference_type
1349 _Distance;
1350 typedef typename iterator_traits<_RandomAccessIterator>::value_type
1351 _ValueType;
1352
1353 _Distance __n = __last - __first;
1354 _Distance __k = __middle - __first;
1355
1356 if (__k == __n - __k)
1357 {
1358 std::swap_ranges(__first, __middle, __middle);
1359 return __middle;
1360 }
1361
1362 _RandomAccessIterator __p = __first;
1363 _RandomAccessIterator __ret = __first + (__last - __middle);
1364
1365 for (;;)
1366 {
1367 if (__k < __n - __k)
1368 {
1369 if (__is_pod(_ValueType) && __k == 1)
1370 {
1371 _ValueType __t = _GLIBCXX_MOVE(*__p);
1372 _GLIBCXX_MOVE3(__p + 1, __p + __n, __p);
1373 *(__p + __n - 1) = _GLIBCXX_MOVE(__t);
1374 return __ret;
1375 }
1376 _RandomAccessIterator __q = __p + __k;
1377 for (_Distance __i = 0; __i < __n - __k; ++ __i)
1378 {
1379 std::iter_swap(__p, __q);
1380 ++__p;
1381 ++__q;
1382 }
1383 __n %= __k;
1384 if (__n == 0)
1385 return __ret;
1386 std::swap(__n, __k);
1387 __k = __n - __k;
1388 }
1389 else
1390 {
1391 __k = __n - __k;
1392 if (__is_pod(_ValueType) && __k == 1)
1393 {
1394 _ValueType __t = _GLIBCXX_MOVE(*(__p + __n - 1));
1395 _GLIBCXX_MOVE_BACKWARD3(__p, __p + __n - 1, __p + __n);
1396 *__p = _GLIBCXX_MOVE(__t);
1397 return __ret;
1398 }
1399 _RandomAccessIterator __q = __p + __n;
1400 __p = __q - __k;
1401 for (_Distance __i = 0; __i < __n - __k; ++ __i)
1402 {
1403 --__p;
1404 --__q;
1405 std::iter_swap(__p, __q);
1406 }
1407 __n %= __k;
1408 if (__n == 0)
1409 return __ret;
1410 std::swap(__n, __k);
1411 }
1412 }
1413 }
1414
1415 // _GLIBCXX_RESOLVE_LIB_DEFECTS
1416 // DR 488. rotate throws away useful information
1417 /**
1418 * @brief Rotate the elements of a sequence.
1419 * @ingroup mutating_algorithms
1420 * @param __first A forward iterator.
1421 * @param __middle A forward iterator.
1422 * @param __last A forward iterator.
1423 * @return first + (last - middle).
1424 *
1425 * Rotates the elements of the range @p [__first,__last) by
1426 * @p (__middle - __first) positions so that the element at @p __middle
1427 * is moved to @p __first, the element at @p __middle+1 is moved to
1428 * @p __first+1 and so on for each element in the range
1429 * @p [__first,__last).
1430 *
1431 * This effectively swaps the ranges @p [__first,__middle) and
1432 * @p [__middle,__last).
1433 *
1434 * Performs
1435 * @p *(__first+(n+(__last-__middle))%(__last-__first))=*(__first+n)
1436 * for each @p n in the range @p [0,__last-__first).
1437 */
1438 template<typename _ForwardIterator>
1439 inline _ForwardIterator
1440 rotate(_ForwardIterator __first, _ForwardIterator __middle,
1441 _ForwardIterator __last)
1442 {
1443 // concept requirements
1444 __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
1445 _ForwardIterator>)
1446 __glibcxx_requires_valid_range(__first, __middle);
1447 __glibcxx_requires_valid_range(__middle, __last);
1448
1449 return std::__rotate(__first, __middle, __last,
1450 std::__iterator_category(__first));
1451 }
1452
1453 } // namespace _V2
1454
1455 /**
1456 * @brief Copy a sequence, rotating its elements.
1457 * @ingroup mutating_algorithms
1458 * @param __first A forward iterator.
1459 * @param __middle A forward iterator.
1460 * @param __last A forward iterator.
1461 * @param __result An output iterator.
1462 * @return An iterator designating the end of the resulting sequence.
1463 *
1464 * Copies the elements of the range @p [__first,__last) to the
1465 * range beginning at @result, rotating the copied elements by
1466 * @p (__middle-__first) positions so that the element at @p __middle
1467 * is moved to @p __result, the element at @p __middle+1 is moved
1468 * to @p __result+1 and so on for each element in the range @p
1469 * [__first,__last).
1470 *
1471 * Performs
1472 * @p *(__result+(n+(__last-__middle))%(__last-__first))=*(__first+n)
1473 * for each @p n in the range @p [0,__last-__first).
1474 */
1475 template<typename _ForwardIterator, typename _OutputIterator>
1476 inline _OutputIterator
1477 rotate_copy(_ForwardIterator __first, _ForwardIterator __middle,
1478 _ForwardIterator __last, _OutputIterator __result)
1479 {
1480 // concept requirements
1481 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
1482 __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
1483 typename iterator_traits<_ForwardIterator>::value_type>)
1484 __glibcxx_requires_valid_range(__first, __middle);
1485 __glibcxx_requires_valid_range(__middle, __last);
1486
1487 return std::copy(__first, __middle,
1488 std::copy(__middle, __last, __result));
1489 }
1490
1491 /// This is a helper function...
1492 template<typename _ForwardIterator, typename _Predicate>
1493 _ForwardIterator
1494 __partition(_ForwardIterator __first, _ForwardIterator __last,
1495 _Predicate __pred, forward_iterator_tag)
1496 {
1497 if (__first == __last)
1498 return __first;
1499
1500 while (__pred(*__first))
1501 if (++__first == __last)
1502 return __first;
1503
1504 _ForwardIterator __next = __first;
1505
1506 while (++__next != __last)
1507 if (__pred(*__next))
1508 {
1509 std::iter_swap(__first, __next);
1510 ++__first;
1511 }
1512
1513 return __first;
1514 }
1515
1516 /// This is a helper function...
1517 template<typename _BidirectionalIterator, typename _Predicate>
1518 _BidirectionalIterator
1519 __partition(_BidirectionalIterator __first, _BidirectionalIterator __last,
1520 _Predicate __pred, bidirectional_iterator_tag)
1521 {
1522 while (true)
1523 {
1524 while (true)
1525 if (__first == __last)
1526 return __first;
1527 else if (__pred(*__first))
1528 ++__first;
1529 else
1530 break;
1531 --__last;
1532 while (true)
1533 if (__first == __last)
1534 return __first;
1535 else if (!bool(__pred(*__last)))
1536 --__last;
1537 else
1538 break;
1539 std::iter_swap(__first, __last);
1540 ++__first;
1541 }
1542 }
1543
1544 // partition
1545
1546 /// This is a helper function...
1547 /// Requires __first != __last and !__pred(__first)
1548 /// and __len == distance(__first, __last).
1549 ///
1550 /// !__pred(__first) allows us to guarantee that we don't
1551 /// move-assign an element onto itself.
1552 template<typename _ForwardIterator, typename _Pointer, typename _Predicate,
1553 typename _Distance>
1554 _ForwardIterator
1555 __stable_partition_adaptive(_ForwardIterator __first,
1556 _ForwardIterator __last,
1557 _Predicate __pred, _Distance __len,
1558 _Pointer __buffer,
1559 _Distance __buffer_size)
1560 {
1561 if (__len == 1)
1562 return __first;
1563
1564 if (__len <= __buffer_size)
1565 {
1566 _ForwardIterator __result1 = __first;
1567 _Pointer __result2 = __buffer;
1568
1569 // The precondition guarantees that !__pred(__first), so
1570 // move that element to the buffer before starting the loop.
1571 // This ensures that we only call __pred once per element.
1572 *__result2 = _GLIBCXX_MOVE(*__first);
1573 ++__result2;
1574 ++__first;
1575 for (; __first != __last; ++__first)
1576 if (__pred(__first))
1577 {
1578 *__result1 = _GLIBCXX_MOVE(*__first);
1579 ++__result1;
1580 }
1581 else
1582 {
1583 *__result2 = _GLIBCXX_MOVE(*__first);
1584 ++__result2;
1585 }
1586
1587 _GLIBCXX_MOVE3(__buffer, __result2, __result1);
1588 return __result1;
1589 }
1590
1591 _ForwardIterator __middle = __first;
1592 std::advance(__middle, __len / 2);
1593 _ForwardIterator __left_split =
1594 std::__stable_partition_adaptive(__first, __middle, __pred,
1595 __len / 2, __buffer,
1596 __buffer_size);
1597
1598 // Advance past true-predicate values to satisfy this
1599 // function's preconditions.
1600 _Distance __right_len = __len - __len / 2;
1601 _ForwardIterator __right_split =
1602 std::__find_if_not_n(__middle, __right_len, __pred);
1603
1604 if (__right_len)
1605 __right_split =
1606 std::__stable_partition_adaptive(__right_split, __last, __pred,
1607 __right_len,
1608 __buffer, __buffer_size);
1609
1610 return std::rotate(__left_split, __middle, __right_split);
1611 }
1612
1613 template<typename _ForwardIterator, typename _Predicate>
1614 _ForwardIterator
1615 __stable_partition(_ForwardIterator __first, _ForwardIterator __last,
1616 _Predicate __pred)
1617 {
1618 __first = std::__find_if_not(__first, __last, __pred);
1619
1620 if (__first == __last)
1621 return __first;
1622
1623 typedef typename iterator_traits<_ForwardIterator>::value_type
1624 _ValueType;
1625 typedef typename iterator_traits<_ForwardIterator>::difference_type
1626 _DistanceType;
1627
1628 _Temporary_buffer<_ForwardIterator, _ValueType>
1629 __buf(__first, std::distance(__first, __last));
1630 return
1631 std::__stable_partition_adaptive(__first, __last, __pred,
1632 _DistanceType(__buf.requested_size()),
1633 __buf.begin(),
1634 _DistanceType(__buf.size()));
1635 }
1636
1637 /**
1638 * @brief Move elements for which a predicate is true to the beginning
1639 * of a sequence, preserving relative ordering.
1640 * @ingroup mutating_algorithms
1641 * @param __first A forward iterator.
1642 * @param __last A forward iterator.
1643 * @param __pred A predicate functor.
1644 * @return An iterator @p middle such that @p __pred(i) is true for each
1645 * iterator @p i in the range @p [first,middle) and false for each @p i
1646 * in the range @p [middle,last).
1647 *
1648 * Performs the same function as @p partition() with the additional
1649 * guarantee that the relative ordering of elements in each group is
1650 * preserved, so any two elements @p x and @p y in the range
1651 * @p [__first,__last) such that @p __pred(x)==__pred(y) will have the same
1652 * relative ordering after calling @p stable_partition().
1653 */
1654 template<typename _ForwardIterator, typename _Predicate>
1655 inline _ForwardIterator
1656 stable_partition(_ForwardIterator __first, _ForwardIterator __last,
1657 _Predicate __pred)
1658 {
1659 // concept requirements
1660 __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
1661 _ForwardIterator>)
1662 __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
1663 typename iterator_traits<_ForwardIterator>::value_type>)
1664 __glibcxx_requires_valid_range(__first, __last);
1665
1666 return std::__stable_partition(__first, __last,
1667 __gnu_cxx::__ops::__pred_iter(__pred));
1668 }
1669
1670 /// This is a helper function for the sort routines.
1671 template<typename _RandomAccessIterator, typename _Compare>
1672 void
1673 __heap_select(_RandomAccessIterator __first,
1674 _RandomAccessIterator __middle,
1675 _RandomAccessIterator __last, _Compare __comp)
1676 {
1677 std::__make_heap(__first, __middle, __comp);
1678 for (_RandomAccessIterator __i = __middle; __i < __last; ++__i)
1679 if (__comp(__i, __first))
1680 std::__pop_heap(__first, __middle, __i, __comp);
1681 }
1682
1683 // partial_sort
1684
1685 template<typename _InputIterator, typename _RandomAccessIterator,
1686 typename _Compare>
1687 _RandomAccessIterator
1688 __partial_sort_copy(_InputIterator __first, _InputIterator __last,
1689 _RandomAccessIterator __result_first,
1690 _RandomAccessIterator __result_last,
1691 _Compare __comp)
1692 {
1693 typedef typename iterator_traits<_InputIterator>::value_type
1694 _InputValueType;
1695 typedef iterator_traits<_RandomAccessIterator> _RItTraits;
1696 typedef typename _RItTraits::difference_type _DistanceType;
1697
1698 if (__result_first == __result_last)
1699 return __result_last;
1700 _RandomAccessIterator __result_real_last = __result_first;
1701 while (__first != __last && __result_real_last != __result_last)
1702 {
1703 *__result_real_last = *__first;
1704 ++__result_real_last;
1705 ++__first;
1706 }
1707
1708 std::__make_heap(__result_first, __result_real_last, __comp);
1709 while (__first != __last)
1710 {
1711 if (__comp(__first, __result_first))
1712 std::__adjust_heap(__result_first, _DistanceType(0),
1713 _DistanceType(__result_real_last
1714 - __result_first),
1715 _InputValueType(*__first), __comp);
1716 ++__first;
1717 }
1718 std::__sort_heap(__result_first, __result_real_last, __comp);
1719 return __result_real_last;
1720 }
1721
1722 /**
1723 * @brief Copy the smallest elements of a sequence.
1724 * @ingroup sorting_algorithms
1725 * @param __first An iterator.
1726 * @param __last Another iterator.
1727 * @param __result_first A random-access iterator.
1728 * @param __result_last Another random-access iterator.
1729 * @return An iterator indicating the end of the resulting sequence.
1730 *
1731 * Copies and sorts the smallest N values from the range @p [__first,__last)
1732 * to the range beginning at @p __result_first, where the number of
1733 * elements to be copied, @p N, is the smaller of @p (__last-__first) and
1734 * @p (__result_last-__result_first).
1735 * After the sort if @e i and @e j are iterators in the range
1736 * @p [__result_first,__result_first+N) such that i precedes j then
1737 * *j<*i is false.
1738 * The value returned is @p __result_first+N.
1739 */
1740 template<typename _InputIterator, typename _RandomAccessIterator>
1741 inline _RandomAccessIterator
1742 partial_sort_copy(_InputIterator __first, _InputIterator __last,
1743 _RandomAccessIterator __result_first,
1744 _RandomAccessIterator __result_last)
1745 {
1746#ifdef _GLIBCXX_CONCEPT_CHECKS
1747 typedef typename iterator_traits<_InputIterator>::value_type
1748 _InputValueType;
1749 typedef typename iterator_traits<_RandomAccessIterator>::value_type
1750 _OutputValueType;
1751#endif
1752
1753 // concept requirements
1754 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
1755 __glibcxx_function_requires(_ConvertibleConcept<_InputValueType,
1756 _OutputValueType>)
1757 __glibcxx_function_requires(_LessThanOpConcept<_InputValueType,
1758 _OutputValueType>)
1759 __glibcxx_function_requires(_LessThanComparableConcept<_OutputValueType>)
1760 __glibcxx_requires_valid_range(__first, __last);
1761 __glibcxx_requires_irreflexive(__first, __last);
1762 __glibcxx_requires_valid_range(__result_first, __result_last);
1763
1764 return std::__partial_sort_copy(__first, __last,
1765 __result_first, __result_last,
1766 __gnu_cxx::__ops::__iter_less_iter());
1767 }
1768
1769 /**
1770 * @brief Copy the smallest elements of a sequence using a predicate for
1771 * comparison.
1772 * @ingroup sorting_algorithms
1773 * @param __first An input iterator.
1774 * @param __last Another input iterator.
1775 * @param __result_first A random-access iterator.
1776 * @param __result_last Another random-access iterator.
1777 * @param __comp A comparison functor.
1778 * @return An iterator indicating the end of the resulting sequence.
1779 *
1780 * Copies and sorts the smallest N values from the range @p [__first,__last)
1781 * to the range beginning at @p result_first, where the number of
1782 * elements to be copied, @p N, is the smaller of @p (__last-__first) and
1783 * @p (__result_last-__result_first).
1784 * After the sort if @e i and @e j are iterators in the range
1785 * @p [__result_first,__result_first+N) such that i precedes j then
1786 * @p __comp(*j,*i) is false.
1787 * The value returned is @p __result_first+N.
1788 */
1789 template<typename _InputIterator, typename _RandomAccessIterator,
1790 typename _Compare>
1791 inline _RandomAccessIterator
1792 partial_sort_copy(_InputIterator __first, _InputIterator __last,
1793 _RandomAccessIterator __result_first,
1794 _RandomAccessIterator __result_last,
1795 _Compare __comp)
1796 {
1797#ifdef _GLIBCXX_CONCEPT_CHECKS
1798 typedef typename iterator_traits<_InputIterator>::value_type
1799 _InputValueType;
1800 typedef typename iterator_traits<_RandomAccessIterator>::value_type
1801 _OutputValueType;
1802#endif
1803
1804 // concept requirements
1805 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
1806 __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
1807 _RandomAccessIterator>)
1808 __glibcxx_function_requires(_ConvertibleConcept<_InputValueType,
1809 _OutputValueType>)
1810 __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
1811 _InputValueType, _OutputValueType>)
1812 __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
1813 _OutputValueType, _OutputValueType>)
1814 __glibcxx_requires_valid_range(__first, __last);
1815 __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
1816 __glibcxx_requires_valid_range(__result_first, __result_last);
1817
1818 return std::__partial_sort_copy(__first, __last,
1819 __result_first, __result_last,
1820 __gnu_cxx::__ops::__iter_comp_iter(__comp));
1821 }
1822
1823 /// This is a helper function for the sort routine.
1824 template<typename _RandomAccessIterator, typename _Compare>
1825 void
1826 __unguarded_linear_insert(_RandomAccessIterator __last,
1827 _Compare __comp)
1828 {
1829 typename iterator_traits<_RandomAccessIterator>::value_type
1830 __val = _GLIBCXX_MOVE(*__last);
1831 _RandomAccessIterator __next = __last;
1832 --__next;
1833 while (__comp(__val, __next))
1834 {
1835 *__last = _GLIBCXX_MOVE(*__next);
1836 __last = __next;
1837 --__next;
1838 }
1839 *__last = _GLIBCXX_MOVE(__val);
1840 }
1841
1842 /// This is a helper function for the sort routine.
1843 template<typename _RandomAccessIterator, typename _Compare>
1844 void
1845 __insertion_sort(_RandomAccessIterator __first,
1846 _RandomAccessIterator __last, _Compare __comp)
1847 {
1848 if (__first == __last) return;
1849
1850 for (_RandomAccessIterator __i = __first + 1; __i != __last; ++__i)
1851 {
1852 if (__comp(__i, __first))
1853 {
1854 typename iterator_traits<_RandomAccessIterator>::value_type
1855 __val = _GLIBCXX_MOVE(*__i);
1856 _GLIBCXX_MOVE_BACKWARD3(__first, __i, __i + 1);
1857 *__first = _GLIBCXX_MOVE(__val);
1858 }
1859 else
1860 std::__unguarded_linear_insert(__i,
1861 __gnu_cxx::__ops::__val_comp_iter(__comp));
1862 }
1863 }
1864
1865 /// This is a helper function for the sort routine.
1866 template<typename _RandomAccessIterator, typename _Compare>
1867 inline void
1868 __unguarded_insertion_sort(_RandomAccessIterator __first,
1869 _RandomAccessIterator __last, _Compare __comp)
1870 {
1871 for (_RandomAccessIterator __i = __first; __i != __last; ++__i)
1872 std::__unguarded_linear_insert(__i,
1873 __gnu_cxx::__ops::__val_comp_iter(__comp));
1874 }
1875
1876 /**
1877 * @doctodo
1878 * This controls some aspect of the sort routines.
1879 */
1880 enum { _S_threshold = 16 };
1881
1882 /// This is a helper function for the sort routine.
1883 template<typename _RandomAccessIterator, typename _Compare>
1884 void
1885 __final_insertion_sort(_RandomAccessIterator __first,
1886 _RandomAccessIterator __last, _Compare __comp)
1887 {
1888 if (__last - __first > int(_S_threshold))
1889 {
1890 std::__insertion_sort(__first, __first + int(_S_threshold), __comp);
1891 std::__unguarded_insertion_sort(__first + int(_S_threshold), __last,
1892 __comp);
1893 }
1894 else
1895 std::__insertion_sort(__first, __last, __comp);
1896 }
1897
1898 /// This is a helper function...
1899 template<typename _RandomAccessIterator, typename _Compare>
1900 _RandomAccessIterator
1901 __unguarded_partition(_RandomAccessIterator __first,
1902 _RandomAccessIterator __last,
1903 _RandomAccessIterator __pivot, _Compare __comp)
1904 {
1905 while (true)
1906 {
1907 while (__comp(__first, __pivot))
1908 ++__first;
1909 --__last;
1910 while (__comp(__pivot, __last))
1911 --__last;
1912 if (!(__first < __last))
1913 return __first;
1914 std::iter_swap(__first, __last);
1915 ++__first;
1916 }
1917 }
1918
1919 /// This is a helper function...
1920 template<typename _RandomAccessIterator, typename _Compare>
1921 inline _RandomAccessIterator
1922 __unguarded_partition_pivot(_RandomAccessIterator __first,
1923 _RandomAccessIterator __last, _Compare __comp)
1924 {
1925 _RandomAccessIterator __mid = __first + (__last - __first) / 2;
1926 std::__move_median_to_first(__first, __first + 1, __mid, __last - 1,
1927 __comp);
1928 return std::__unguarded_partition(__first + 1, __last, __first, __comp);
1929 }
1930
1931 template<typename _RandomAccessIterator, typename _Compare>
1932 inline void
1933 __partial_sort(_RandomAccessIterator __first,
1934 _RandomAccessIterator __middle,
1935 _RandomAccessIterator __last,
1936 _Compare __comp)
1937 {
1938 std::__heap_select(__first, __middle, __last, __comp);
1939 std::__sort_heap(__first, __middle, __comp);
1940 }
1941
1942 /// This is a helper function for the sort routine.
1943 template<typename _RandomAccessIterator, typename _Size, typename _Compare>
1944 void
1945 __introsort_loop(_RandomAccessIterator __first,
1946 _RandomAccessIterator __last,
1947 _Size __depth_limit, _Compare __comp)
1948 {
1949 while (__last - __first > int(_S_threshold))
1950 {
1951 if (__depth_limit == 0)
1952 {
1953 std::__partial_sort(__first, __last, __last, __comp);
1954 return;
1955 }
1956 --__depth_limit;
1957 _RandomAccessIterator __cut =
1958 std::__unguarded_partition_pivot(__first, __last, __comp);
1959 std::__introsort_loop(__cut, __last, __depth_limit, __comp);
1960 __last = __cut;
1961 }
1962 }
1963
1964 // sort
1965
1966 template<typename _RandomAccessIterator, typename _Compare>
1967 inline void
1968 __sort(_RandomAccessIterator __first, _RandomAccessIterator __last,
1969 _Compare __comp)
1970 {
1971 if (__first != __last)
1972 {
1973 std::__introsort_loop(__first, __last,
1974 std::__lg(__last - __first) * 2,
1975 __comp);
1976 std::__final_insertion_sort(__first, __last, __comp);
1977 }
1978 }
1979
1980 template<typename _RandomAccessIterator, typename _Size, typename _Compare>
1981 void
1982 __introselect(_RandomAccessIterator __first, _RandomAccessIterator __nth,
1983 _RandomAccessIterator __last, _Size __depth_limit,
1984 _Compare __comp)
1985 {
1986 while (__last - __first > 3)
1987 {
1988 if (__depth_limit == 0)
1989 {
1990 std::__heap_select(__first, __nth + 1, __last, __comp);
1991 // Place the nth largest element in its final position.
1992 std::iter_swap(__first, __nth);
1993 return;
1994 }
1995 --__depth_limit;
1996 _RandomAccessIterator __cut =
1997 std::__unguarded_partition_pivot(__first, __last, __comp);
1998 if (__cut <= __nth)
1999 __first = __cut;
2000 else
2001 __last = __cut;
2002 }
2003 std::__insertion_sort(__first, __last, __comp);
2004 }
2005
2006 // nth_element
2007
2008 // lower_bound moved to stl_algobase.h
2009
2010 /**
2011 * @brief Finds the first position in which @p __val could be inserted
2012 * without changing the ordering.
2013 * @ingroup binary_search_algorithms
2014 * @param __first An iterator.
2015 * @param __last Another iterator.
2016 * @param __val The search term.
2017 * @param __comp A functor to use for comparisons.
2018 * @return An iterator pointing to the first element <em>not less
2019 * than</em> @p __val, or end() if every element is less
2020 * than @p __val.
2021 * @ingroup binary_search_algorithms
2022 *
2023 * The comparison function should have the same effects on ordering as
2024 * the function used for the initial sort.
2025 */
2026 template<typename _ForwardIterator, typename _Tp, typename _Compare>
2027 inline _ForwardIterator
2028 lower_bound(_ForwardIterator __first, _ForwardIterator __last,
2029 const _Tp& __val, _Compare __comp)
2030 {
2031 // concept requirements
2032 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
2033 __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
2034 typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
2035 __glibcxx_requires_partitioned_lower_pred(__first, __last,
2036 __val, __comp);
2037
2038 return std::__lower_bound(__first, __last, __val,
2039 __gnu_cxx::__ops::__iter_comp_val(__comp));
2040 }
2041
2042 template<typename _ForwardIterator, typename _Tp, typename _Compare>
2043 _ForwardIterator
2044 __upper_bound(_ForwardIterator __first, _ForwardIterator __last,
2045 const _Tp& __val, _Compare __comp)
2046 {
2047 typedef typename iterator_traits<_ForwardIterator>::difference_type
2048 _DistanceType;
2049
2050 _DistanceType __len = std::distance(__first, __last);
2051
2052 while (__len > 0)
2053 {
2054 _DistanceType __half = __len >> 1;
2055 _ForwardIterator __middle = __first;
2056 std::advance(__middle, __half);
2057 if (__comp(__val, __middle))
2058 __len = __half;
2059 else
2060 {
2061 __first = __middle;
2062 ++__first;
2063 __len = __len - __half - 1;
2064 }
2065 }
2066 return __first;
2067 }
2068
2069 /**
2070 * @brief Finds the last position in which @p __val could be inserted
2071 * without changing the ordering.
2072 * @ingroup binary_search_algorithms
2073 * @param __first An iterator.
2074 * @param __last Another iterator.
2075 * @param __val The search term.
2076 * @return An iterator pointing to the first element greater than @p __val,
2077 * or end() if no elements are greater than @p __val.
2078 * @ingroup binary_search_algorithms
2079 */
2080 template<typename _ForwardIterator, typename _Tp>
2081 inline _ForwardIterator
2082 upper_bound(_ForwardIterator __first, _ForwardIterator __last,
2083 const _Tp& __val)
2084 {
2085 // concept requirements
2086 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
2087 __glibcxx_function_requires(_LessThanOpConcept<
2088 _Tp, typename iterator_traits<_ForwardIterator>::value_type>)
2089 __glibcxx_requires_partitioned_upper(__first, __last, __val);
2090
2091 return std::__upper_bound(__first, __last, __val,
2092 __gnu_cxx::__ops::__val_less_iter());
2093 }
2094
2095 /**
2096 * @brief Finds the last position in which @p __val could be inserted
2097 * without changing the ordering.
2098 * @ingroup binary_search_algorithms
2099 * @param __first An iterator.
2100 * @param __last Another iterator.
2101 * @param __val The search term.
2102 * @param __comp A functor to use for comparisons.
2103 * @return An iterator pointing to the first element greater than @p __val,
2104 * or end() if no elements are greater than @p __val.
2105 * @ingroup binary_search_algorithms
2106 *
2107 * The comparison function should have the same effects on ordering as
2108 * the function used for the initial sort.
2109 */
2110 template<typename _ForwardIterator, typename _Tp, typename _Compare>
2111 inline _ForwardIterator
2112 upper_bound(_ForwardIterator __first, _ForwardIterator __last,
2113 const _Tp& __val, _Compare __comp)
2114 {
2115 // concept requirements
2116 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
2117 __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
2118 _Tp, typename iterator_traits<_ForwardIterator>::value_type>)
2119 __glibcxx_requires_partitioned_upper_pred(__first, __last,
2120 __val, __comp);
2121
2122 return std::__upper_bound(__first, __last, __val,
2123 __gnu_cxx::__ops::__val_comp_iter(__comp));
2124 }
2125
2126 template<typename _ForwardIterator, typename _Tp,
2127 typename _CompareItTp, typename _CompareTpIt>
2128 pair<_ForwardIterator, _ForwardIterator>
2129 __equal_range(_ForwardIterator __first, _ForwardIterator __last,
2130 const _Tp& __val,
2131 _CompareItTp __comp_it_val, _CompareTpIt __comp_val_it)
2132 {
2133 typedef typename iterator_traits<_ForwardIterator>::difference_type
2134 _DistanceType;
2135
2136 _DistanceType __len = std::distance(__first, __last);
2137
2138 while (__len > 0)
2139 {
2140 _DistanceType __half = __len >> 1;
2141 _ForwardIterator __middle = __first;
2142 std::advance(__middle, __half);
2143 if (__comp_it_val(__middle, __val))
2144 {
2145 __first = __middle;
2146 ++__first;
2147 __len = __len - __half - 1;
2148 }
2149 else if (__comp_val_it(__val, __middle))
2150 __len = __half;
2151 else
2152 {
2153 _ForwardIterator __left
2154 = std::__lower_bound(__first, __middle, __val, __comp_it_val);
2155 std::advance(__first, __len);
2156 _ForwardIterator __right
2157 = std::__upper_bound(++__middle, __first, __val, __comp_val_it);
2158 return pair<_ForwardIterator, _ForwardIterator>(__left, __right);
2159 }
2160 }
2161 return pair<_ForwardIterator, _ForwardIterator>(__first, __first);
2162 }
2163
2164 /**
2165 * @brief Finds the largest subrange in which @p __val could be inserted
2166 * at any place in it without changing the ordering.
2167 * @ingroup binary_search_algorithms
2168 * @param __first An iterator.
2169 * @param __last Another iterator.
2170 * @param __val The search term.
2171 * @return An pair of iterators defining the subrange.
2172 * @ingroup binary_search_algorithms
2173 *
2174 * This is equivalent to
2175 * @code
2176 * std::make_pair(lower_bound(__first, __last, __val),
2177 * upper_bound(__first, __last, __val))
2178 * @endcode
2179 * but does not actually call those functions.
2180 */
2181 template<typename _ForwardIterator, typename _Tp>
2182 inline pair<_ForwardIterator, _ForwardIterator>
2183 equal_range(_ForwardIterator __first, _ForwardIterator __last,
2184 const _Tp& __val)
2185 {
2186 // concept requirements
2187 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
2188 __glibcxx_function_requires(_LessThanOpConcept<
2189 typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
2190 __glibcxx_function_requires(_LessThanOpConcept<
2191 _Tp, typename iterator_traits<_ForwardIterator>::value_type>)
2192 __glibcxx_requires_partitioned_lower(__first, __last, __val);
2193 __glibcxx_requires_partitioned_upper(__first, __last, __val);
2194
2195 return std::__equal_range(__first, __last, __val,
2196 __gnu_cxx::__ops::__iter_less_val(),
2197 __gnu_cxx::__ops::__val_less_iter());
2198 }
2199
2200 /**
2201 * @brief Finds the largest subrange in which @p __val could be inserted
2202 * at any place in it without changing the ordering.
2203 * @param __first An iterator.
2204 * @param __last Another iterator.
2205 * @param __val The search term.
2206 * @param __comp A functor to use for comparisons.
2207 * @return An pair of iterators defining the subrange.
2208 * @ingroup binary_search_algorithms
2209 *
2210 * This is equivalent to
2211 * @code
2212 * std::make_pair(lower_bound(__first, __last, __val, __comp),
2213 * upper_bound(__first, __last, __val, __comp))
2214 * @endcode
2215 * but does not actually call those functions.
2216 */
2217 template<typename _ForwardIterator, typename _Tp, typename _Compare>
2218 inline pair<_ForwardIterator, _ForwardIterator>
2219 equal_range(_ForwardIterator __first, _ForwardIterator __last,
2220 const _Tp& __val, _Compare __comp)
2221 {
2222 // concept requirements
2223 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
2224 __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
2225 typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
2226 __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
2227 _Tp, typename iterator_traits<_ForwardIterator>::value_type>)
2228 __glibcxx_requires_partitioned_lower_pred(__first, __last,
2229 __val, __comp);
2230 __glibcxx_requires_partitioned_upper_pred(__first, __last,
2231 __val, __comp);
2232
2233 return std::__equal_range(__first, __last, __val,
2234 __gnu_cxx::__ops::__iter_comp_val(__comp),
2235 __gnu_cxx::__ops::__val_comp_iter(__comp));
2236 }
2237
2238 /**
2239 * @brief Determines whether an element exists in a range.
2240 * @ingroup binary_search_algorithms
2241 * @param __first An iterator.
2242 * @param __last Another iterator.
2243 * @param __val The search term.
2244 * @return True if @p __val (or its equivalent) is in [@p
2245 * __first,@p __last ].
2246 *
2247 * Note that this does not actually return an iterator to @p __val. For
2248 * that, use std::find or a container's specialized find member functions.
2249 */
2250 template<typename _ForwardIterator, typename _Tp>
2251 bool
2252 binary_search(_ForwardIterator __first, _ForwardIterator __last,
2253 const _Tp& __val)
2254 {
2255 // concept requirements
2256 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
2257 __glibcxx_function_requires(_LessThanOpConcept<
2258 _Tp, typename iterator_traits<_ForwardIterator>::value_type>)
2259 __glibcxx_requires_partitioned_lower(__first, __last, __val);
2260 __glibcxx_requires_partitioned_upper(__first, __last, __val);
2261
2262 _ForwardIterator __i
2263 = std::__lower_bound(__first, __last, __val,
2264 __gnu_cxx::__ops::__iter_less_val());
2265 return __i != __last && !(__val < *__i);
2266 }
2267
2268 /**
2269 * @brief Determines whether an element exists in a range.
2270 * @ingroup binary_search_algorithms
2271 * @param __first An iterator.
2272 * @param __last Another iterator.
2273 * @param __val The search term.
2274 * @param __comp A functor to use for comparisons.
2275 * @return True if @p __val (or its equivalent) is in @p [__first,__last].
2276 *
2277 * Note that this does not actually return an iterator to @p __val. For
2278 * that, use std::find or a container's specialized find member functions.
2279 *
2280 * The comparison function should have the same effects on ordering as
2281 * the function used for the initial sort.
2282 */
2283 template<typename _ForwardIterator, typename _Tp, typename _Compare>
2284 bool
2285 binary_search(_ForwardIterator __first, _ForwardIterator __last,
2286 const _Tp& __val, _Compare __comp)
2287 {
2288 // concept requirements
2289 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
2290 __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
2291 _Tp, typename iterator_traits<_ForwardIterator>::value_type>)
2292 __glibcxx_requires_partitioned_lower_pred(__first, __last,
2293 __val, __comp);
2294 __glibcxx_requires_partitioned_upper_pred(__first, __last,
2295 __val, __comp);
2296
2297 _ForwardIterator __i
2298 = std::__lower_bound(__first, __last, __val,
2299 __gnu_cxx::__ops::__iter_comp_val(__comp));
2300 return __i != __last && !bool(__comp(__val, *__i));
2301 }
2302
2303 // merge
2304
2305 /// This is a helper function for the __merge_adaptive routines.
2306 template<typename _InputIterator1, typename _InputIterator2,
2307 typename _OutputIterator, typename _Compare>
2308 void
2309 __move_merge_adaptive(_InputIterator1 __first1, _InputIterator1 __last1,
2310 _InputIterator2 __first2, _InputIterator2 __last2,
2311 _OutputIterator __result, _Compare __comp)
2312 {
2313 while (__first1 != __last1 && __first2 != __last2)
2314 {
2315 if (__comp(__first2, __first1))
2316 {
2317 *__result = _GLIBCXX_MOVE(*__first2);
2318 ++__first2;
2319 }
2320 else
2321 {
2322 *__result = _GLIBCXX_MOVE(*__first1);
2323 ++__first1;
2324 }
2325 ++__result;
2326 }
2327 if (__first1 != __last1)
2328 _GLIBCXX_MOVE3(__first1, __last1, __result);
2329 }
2330
2331 /// This is a helper function for the __merge_adaptive routines.
2332 template<typename _BidirectionalIterator1, typename _BidirectionalIterator2,
2333 typename _BidirectionalIterator3, typename _Compare>
2334 void
2335 __move_merge_adaptive_backward(_BidirectionalIterator1 __first1,
2336 _BidirectionalIterator1 __last1,
2337 _BidirectionalIterator2 __first2,
2338 _BidirectionalIterator2 __last2,
2339 _BidirectionalIterator3 __result,
2340 _Compare __comp)
2341 {
2342 if (__first1 == __last1)
2343 {
2344 _GLIBCXX_MOVE_BACKWARD3(__first2, __last2, __result);
2345 return;
2346 }
2347 else if (__first2 == __last2)
2348 return;
2349
2350 --__last1;
2351 --__last2;
2352 while (true)
2353 {
2354 if (__comp(__last2, __last1))
2355 {
2356 *--__result = _GLIBCXX_MOVE(*__last1);
2357 if (__first1 == __last1)
2358 {
2359 _GLIBCXX_MOVE_BACKWARD3(__first2, ++__last2, __result);
2360 return;
2361 }
2362 --__last1;
2363 }
2364 else
2365 {
2366 *--__result = _GLIBCXX_MOVE(*__last2);
2367 if (__first2 == __last2)
2368 return;
2369 --__last2;
2370 }
2371 }
2372 }
2373
2374 /// This is a helper function for the merge routines.
2375 template<typename _BidirectionalIterator1, typename _BidirectionalIterator2,
2376 typename _Distance>
2377 _BidirectionalIterator1
2378 __rotate_adaptive(_BidirectionalIterator1 __first,
2379 _BidirectionalIterator1 __middle,
2380 _BidirectionalIterator1 __last,
2381 _Distance __len1, _Distance __len2,
2382 _BidirectionalIterator2 __buffer,
2383 _Distance __buffer_size)
2384 {
2385 _BidirectionalIterator2 __buffer_end;
2386 if (__len1 > __len2 && __len2 <= __buffer_size)
2387 {
2388 if (__len2)
2389 {
2390 __buffer_end = _GLIBCXX_MOVE3(__middle, __last, __buffer);
2391 _GLIBCXX_MOVE_BACKWARD3(__first, __middle, __last);
2392 return _GLIBCXX_MOVE3(__buffer, __buffer_end, __first);
2393 }
2394 else
2395 return __first;
2396 }
2397 else if (__len1 <= __buffer_size)
2398 {
2399 if (__len1)
2400 {
2401 __buffer_end = _GLIBCXX_MOVE3(__first, __middle, __buffer);
2402 _GLIBCXX_MOVE3(__middle, __last, __first);
2403 return _GLIBCXX_MOVE_BACKWARD3(__buffer, __buffer_end, __last);
2404 }
2405 else
2406 return __last;
2407 }
2408 else
2409 return std::rotate(__first, __middle, __last);
2410 }
2411
2412 /// This is a helper function for the merge routines.
2413 template<typename _BidirectionalIterator, typename _Distance,
2414 typename _Pointer, typename _Compare>
2415 void
2416 __merge_adaptive(_BidirectionalIterator __first,
2417 _BidirectionalIterator __middle,
2418 _BidirectionalIterator __last,
2419 _Distance __len1, _Distance __len2,
2420 _Pointer __buffer, _Distance __buffer_size,
2421 _Compare __comp)
2422 {
2423 if (__len1 <= __len2 && __len1 <= __buffer_size)
2424 {
2425 _Pointer __buffer_end = _GLIBCXX_MOVE3(__first, __middle, __buffer);
2426 std::__move_merge_adaptive(__buffer, __buffer_end, __middle, __last,
2427 __first, __comp);
2428 }
2429 else if (__len2 <= __buffer_size)
2430 {
2431 _Pointer __buffer_end = _GLIBCXX_MOVE3(__middle, __last, __buffer);
2432 std::__move_merge_adaptive_backward(__first, __middle, __buffer,
2433 __buffer_end, __last, __comp);
2434 }
2435 else
2436 {
2437 _BidirectionalIterator __first_cut = __first;
2438 _BidirectionalIterator __second_cut = __middle;
2439 _Distance __len11 = 0;
2440 _Distance __len22 = 0;
2441 if (__len1 > __len2)
2442 {
2443 __len11 = __len1 / 2;
2444 std::advance(__first_cut, __len11);
2445 __second_cut
2446 = std::__lower_bound(__middle, __last, *__first_cut,
2447 __gnu_cxx::__ops::__iter_comp_val(__comp));
2448 __len22 = std::distance(__middle, __second_cut);
2449 }
2450 else
2451 {
2452 __len22 = __len2 / 2;
2453 std::advance(__second_cut, __len22);
2454 __first_cut
2455 = std::__upper_bound(__first, __middle, *__second_cut,
2456 __gnu_cxx::__ops::__val_comp_iter(__comp));
2457 __len11 = std::distance(__first, __first_cut);
2458 }
2459
2460 _BidirectionalIterator __new_middle
2461 = std::__rotate_adaptive(__first_cut, __middle, __second_cut,
2462 __len1 - __len11, __len22, __buffer,
2463 __buffer_size);
2464 std::__merge_adaptive(__first, __first_cut, __new_middle, __len11,
2465 __len22, __buffer, __buffer_size, __comp);
2466 std::__merge_adaptive(__new_middle, __second_cut, __last,
2467 __len1 - __len11,
2468 __len2 - __len22, __buffer,
2469 __buffer_size, __comp);
2470 }
2471 }
2472
2473 /// This is a helper function for the merge routines.
2474 template<typename _BidirectionalIterator, typename _Distance,
2475 typename _Compare>
2476 void
2477 __merge_without_buffer(_BidirectionalIterator __first,
2478 _BidirectionalIterator __middle,
2479 _BidirectionalIterator __last,
2480 _Distance __len1, _Distance __len2,
2481 _Compare __comp)
2482 {
2483 if (__len1 == 0 || __len2 == 0)
2484 return;
2485
2486 if (__len1 + __len2 == 2)
2487 {
2488 if (__comp(__middle, __first))
2489 std::iter_swap(__first, __middle);
2490 return;
2491 }
2492
2493 _BidirectionalIterator __first_cut = __first;
2494 _BidirectionalIterator __second_cut = __middle;
2495 _Distance __len11 = 0;
2496 _Distance __len22 = 0;
2497 if (__len1 > __len2)
2498 {
2499 __len11 = __len1 / 2;
2500 std::advance(__first_cut, __len11);
2501 __second_cut
2502 = std::__lower_bound(__middle, __last, *__first_cut,
2503 __gnu_cxx::__ops::__iter_comp_val(__comp));
2504 __len22 = std::distance(__middle, __second_cut);
2505 }
2506 else
2507 {
2508 __len22 = __len2 / 2;
2509 std::advance(__second_cut, __len22);
2510 __first_cut
2511 = std::__upper_bound(__first, __middle, *__second_cut,
2512 __gnu_cxx::__ops::__val_comp_iter(__comp));
2513 __len11 = std::distance(__first, __first_cut);
2514 }
2515
2516 _BidirectionalIterator __new_middle
2517 = std::rotate(__first_cut, __middle, __second_cut);
2518 std::__merge_without_buffer(__first, __first_cut, __new_middle,
2519 __len11, __len22, __comp);
2520 std::__merge_without_buffer(__new_middle, __second_cut, __last,
2521 __len1 - __len11, __len2 - __len22, __comp);
2522 }
2523
2524 template<typename _BidirectionalIterator, typename _Compare>
2525 void
2526 __inplace_merge(_BidirectionalIterator __first,
2527 _BidirectionalIterator __middle,
2528 _BidirectionalIterator __last,
2529 _Compare __comp)
2530 {
2531 typedef typename iterator_traits<_BidirectionalIterator>::value_type
2532 _ValueType;
2533 typedef typename iterator_traits<_BidirectionalIterator>::difference_type
2534 _DistanceType;
2535
2536 if (__first == __middle || __middle == __last)
2537 return;
2538
2539 const _DistanceType __len1 = std::distance(__first, __middle);
2540 const _DistanceType __len2 = std::distance(__middle, __last);
2541
2542 typedef _Temporary_buffer<_BidirectionalIterator, _ValueType> _TmpBuf;
2543 _TmpBuf __buf(__first, __len1 + __len2);
2544
2545 if (__buf.begin() == 0)
2546 std::__merge_without_buffer
2547 (__first, __middle, __last, __len1, __len2, __comp);
2548 else
2549 std::__merge_adaptive
2550 (__first, __middle, __last, __len1, __len2, __buf.begin(),
2551 _DistanceType(__buf.size()), __comp);
2552 }
2553
2554 /**
2555 * @brief Merges two sorted ranges in place.
2556 * @ingroup sorting_algorithms
2557 * @param __first An iterator.
2558 * @param __middle Another iterator.
2559 * @param __last Another iterator.
2560 * @return Nothing.
2561 *
2562 * Merges two sorted and consecutive ranges, [__first,__middle) and
2563 * [__middle,__last), and puts the result in [__first,__last). The
2564 * output will be sorted. The sort is @e stable, that is, for
2565 * equivalent elements in the two ranges, elements from the first
2566 * range will always come before elements from the second.
2567 *
2568 * If enough additional memory is available, this takes (__last-__first)-1
2569 * comparisons. Otherwise an NlogN algorithm is used, where N is
2570 * distance(__first,__last).
2571 */
2572 template<typename _BidirectionalIterator>
2573 inline void
2574 inplace_merge(_BidirectionalIterator __first,
2575 _BidirectionalIterator __middle,
2576 _BidirectionalIterator __last)
2577 {
2578 // concept requirements
2579 __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<
2580 _BidirectionalIterator>)
2581 __glibcxx_function_requires(_LessThanComparableConcept<
2582 typename iterator_traits<_BidirectionalIterator>::value_type>)
2583 __glibcxx_requires_sorted(__first, __middle);
2584 __glibcxx_requires_sorted(__middle, __last);
2585 __glibcxx_requires_irreflexive(__first, __last);
2586
2587 std::__inplace_merge(__first, __middle, __last,
2588 __gnu_cxx::__ops::__iter_less_iter());
2589 }
2590
2591 /**
2592 * @brief Merges two sorted ranges in place.
2593 * @ingroup sorting_algorithms
2594 * @param __first An iterator.
2595 * @param __middle Another iterator.
2596 * @param __last Another iterator.
2597 * @param __comp A functor to use for comparisons.
2598 * @return Nothing.
2599 *
2600 * Merges two sorted and consecutive ranges, [__first,__middle) and
2601 * [middle,last), and puts the result in [__first,__last). The output will
2602 * be sorted. The sort is @e stable, that is, for equivalent
2603 * elements in the two ranges, elements from the first range will always
2604 * come before elements from the second.
2605 *
2606 * If enough additional memory is available, this takes (__last-__first)-1
2607 * comparisons. Otherwise an NlogN algorithm is used, where N is
2608 * distance(__first,__last).
2609 *
2610 * The comparison function should have the same effects on ordering as
2611 * the function used for the initial sort.
2612 */
2613 template<typename _BidirectionalIterator, typename _Compare>
2614 inline void
2615 inplace_merge(_BidirectionalIterator __first,
2616 _BidirectionalIterator __middle,
2617 _BidirectionalIterator __last,
2618 _Compare __comp)
2619 {
2620 // concept requirements
2621 __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<
2622 _BidirectionalIterator>)
2623 __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
2624 typename iterator_traits<_BidirectionalIterator>::value_type,
2625 typename iterator_traits<_BidirectionalIterator>::value_type>)
2626 __glibcxx_requires_sorted_pred(__first, __middle, __comp);
2627 __glibcxx_requires_sorted_pred(__middle, __last, __comp);
2628 __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
2629
2630 std::__inplace_merge(__first, __middle, __last,
2631 __gnu_cxx::__ops::__iter_comp_iter(__comp));
2632 }
2633
2634
2635 /// This is a helper function for the __merge_sort_loop routines.
2636 template<typename _InputIterator, typename _OutputIterator,
2637 typename _Compare>
2638 _OutputIterator
2639 __move_merge(_InputIterator __first1, _InputIterator __last1,
2640 _InputIterator __first2, _InputIterator __last2,
2641 _OutputIterator __result, _Compare __comp)
2642 {
2643 while (__first1 != __last1 && __first2 != __last2)
2644 {
2645 if (__comp(__first2, __first1))
2646 {
2647 *__result = _GLIBCXX_MOVE(*__first2);
2648 ++__first2;
2649 }
2650 else
2651 {
2652 *__result = _GLIBCXX_MOVE(*__first1);
2653 ++__first1;
2654 }
2655 ++__result;
2656 }
2657 return _GLIBCXX_MOVE3(__first2, __last2,
2658 _GLIBCXX_MOVE3(__first1, __last1,
2659 __result));
2660 }
2661
2662 template<typename _RandomAccessIterator1, typename _RandomAccessIterator2,
2663 typename _Distance, typename _Compare>
2664 void
2665 __merge_sort_loop(_RandomAccessIterator1 __first,
2666 _RandomAccessIterator1 __last,
2667 _RandomAccessIterator2 __result, _Distance __step_size,
2668 _Compare __comp)
2669 {
2670 const _Distance __two_step = 2 * __step_size;
2671
2672 while (__last - __first >= __two_step)
2673 {
2674 __result = std::__move_merge(__first, __first + __step_size,
2675 __first + __step_size,
2676 __first + __two_step,
2677 __result, __comp);
2678 __first += __two_step;
2679 }
2680 __step_size = std::min(_Distance(__last - __first), __step_size);
2681
2682 std::__move_merge(__first, __first + __step_size,
2683 __first + __step_size, __last, __result, __comp);
2684 }
2685
2686 template<typename _RandomAccessIterator, typename _Distance,
2687 typename _Compare>
2688 void
2689 __chunk_insertion_sort(_RandomAccessIterator __first,
2690 _RandomAccessIterator __last,
2691 _Distance __chunk_size, _Compare __comp)
2692 {
2693 while (__last - __first >= __chunk_size)
2694 {
2695 std::__insertion_sort(__first, __first + __chunk_size, __comp);
2696 __first += __chunk_size;
2697 }
2698 std::__insertion_sort(__first, __last, __comp);
2699 }
2700
2701 enum { _S_chunk_size = 7 };
2702
2703 template<typename _RandomAccessIterator, typename _Pointer, typename _Compare>
2704 void
2705 __merge_sort_with_buffer(_RandomAccessIterator __first,
2706 _RandomAccessIterator __last,
2707 _Pointer __buffer, _Compare __comp)
2708 {
2709 typedef typename iterator_traits<_RandomAccessIterator>::difference_type
2710 _Distance;
2711
2712 const _Distance __len = __last - __first;
2713 const _Pointer __buffer_last = __buffer + __len;
2714
2715 _Distance __step_size = _S_chunk_size;
2716 std::__chunk_insertion_sort(__first, __last, __step_size, __comp);
2717
2718 while (__step_size < __len)
2719 {
2720 std::__merge_sort_loop(__first, __last, __buffer,
2721 __step_size, __comp);
2722 __step_size *= 2;
2723 std::__merge_sort_loop(__buffer, __buffer_last, __first,
2724 __step_size, __comp);
2725 __step_size *= 2;
2726 }
2727 }
2728
2729 template<typename _RandomAccessIterator, typename _Pointer,
2730 typename _Distance, typename _Compare>
2731 void
2732 __stable_sort_adaptive(_RandomAccessIterator __first,
2733 _RandomAccessIterator __last,
2734 _Pointer __buffer, _Distance __buffer_size,
2735 _Compare __comp)
2736 {
2737 const _Distance __len = (__last - __first + 1) / 2;
2738 const _RandomAccessIterator __middle = __first + __len;
2739 if (__len > __buffer_size)
2740 {
2741 std::__stable_sort_adaptive(__first, __middle, __buffer,
2742 __buffer_size, __comp);
2743 std::__stable_sort_adaptive(__middle, __last, __buffer,
2744 __buffer_size, __comp);
2745 }
2746 else
2747 {
2748 std::__merge_sort_with_buffer(__first, __middle, __buffer, __comp);
2749 std::__merge_sort_with_buffer(__middle, __last, __buffer, __comp);
2750 }
2751 std::__merge_adaptive(__first, __middle, __last,
2752 _Distance(__middle - __first),
2753 _Distance(__last - __middle),
2754 __buffer, __buffer_size,
2755 __comp);
2756 }
2757
2758 /// This is a helper function for the stable sorting routines.
2759 template<typename _RandomAccessIterator, typename _Compare>
2760 void
2761 __inplace_stable_sort(_RandomAccessIterator __first,
2762 _RandomAccessIterator __last, _Compare __comp)
2763 {
2764 if (__last - __first < 15)
2765 {
2766 std::__insertion_sort(__first, __last, __comp);
2767 return;
2768 }
2769 _RandomAccessIterator __middle = __first + (__last - __first) / 2;
2770 std::__inplace_stable_sort(__first, __middle, __comp);
2771 std::__inplace_stable_sort(__middle, __last, __comp);
2772 std::__merge_without_buffer(__first, __middle, __last,
2773 __middle - __first,
2774 __last - __middle,
2775 __comp);
2776 }
2777
2778 // stable_sort
2779
2780 // Set algorithms: includes, set_union, set_intersection, set_difference,
2781 // set_symmetric_difference. All of these algorithms have the precondition
2782 // that their input ranges are sorted and the postcondition that their output
2783 // ranges are sorted.
2784
2785 template<typename _InputIterator1, typename _InputIterator2,
2786 typename _Compare>
2787 bool
2788 __includes(_InputIterator1 __first1, _InputIterator1 __last1,
2789 _InputIterator2 __first2, _InputIterator2 __last2,
2790 _Compare __comp)
2791 {
2792 while (__first1 != __last1 && __first2 != __last2)
2793 if (__comp(__first2, __first1))
2794 return false;
2795 else if (__comp(__first1, __first2))
2796 ++__first1;
2797 else
2798 {
2799 ++__first1;
2800 ++__first2;
2801 }
2802
2803 return __first2 == __last2;
2804 }
2805
2806 /**
2807 * @brief Determines whether all elements of a sequence exists in a range.
2808 * @param __first1 Start of search range.
2809 * @param __last1 End of search range.
2810 * @param __first2 Start of sequence
2811 * @param __last2 End of sequence.
2812 * @return True if each element in [__first2,__last2) is contained in order
2813 * within [__first1,__last1). False otherwise.
2814 * @ingroup set_algorithms
2815 *
2816 * This operation expects both [__first1,__last1) and
2817 * [__first2,__last2) to be sorted. Searches for the presence of
2818 * each element in [__first2,__last2) within [__first1,__last1).
2819 * The iterators over each range only move forward, so this is a
2820 * linear algorithm. If an element in [__first2,__last2) is not
2821 * found before the search iterator reaches @p __last2, false is
2822 * returned.
2823 */
2824 template<typename _InputIterator1, typename _InputIterator2>
2825 inline bool
2826 includes(_InputIterator1 __first1, _InputIterator1 __last1,
2827 _InputIterator2 __first2, _InputIterator2 __last2)
2828 {
2829 // concept requirements
2830 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
2831 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
2832 __glibcxx_function_requires(_LessThanOpConcept<
2833 typename iterator_traits<_InputIterator1>::value_type,
2834 typename iterator_traits<_InputIterator2>::value_type>)
2835 __glibcxx_function_requires(_LessThanOpConcept<
2836 typename iterator_traits<_InputIterator2>::value_type,
2837 typename iterator_traits<_InputIterator1>::value_type>)
2838 __glibcxx_requires_sorted_set(__first1, __last1, __first2);
2839 __glibcxx_requires_sorted_set(__first2, __last2, __first1);
2840 __glibcxx_requires_irreflexive2(__first1, __last1);
2841 __glibcxx_requires_irreflexive2(__first2, __last2);
2842
2843 return std::__includes(__first1, __last1, __first2, __last2,
2844 __gnu_cxx::__ops::__iter_less_iter());
2845 }
2846
2847 /**
2848 * @brief Determines whether all elements of a sequence exists in a range
2849 * using comparison.
2850 * @ingroup set_algorithms
2851 * @param __first1 Start of search range.
2852 * @param __last1 End of search range.
2853 * @param __first2 Start of sequence
2854 * @param __last2 End of sequence.
2855 * @param __comp Comparison function to use.
2856 * @return True if each element in [__first2,__last2) is contained
2857 * in order within [__first1,__last1) according to comp. False
2858 * otherwise. @ingroup set_algorithms
2859 *
2860 * This operation expects both [__first1,__last1) and
2861 * [__first2,__last2) to be sorted. Searches for the presence of
2862 * each element in [__first2,__last2) within [__first1,__last1),
2863 * using comp to decide. The iterators over each range only move
2864 * forward, so this is a linear algorithm. If an element in
2865 * [__first2,__last2) is not found before the search iterator
2866 * reaches @p __last2, false is returned.
2867 */
2868 template<typename _InputIterator1, typename _InputIterator2,
2869 typename _Compare>
2870 inline bool
2871 includes(_InputIterator1 __first1, _InputIterator1 __last1,
2872 _InputIterator2 __first2, _InputIterator2 __last2,
2873 _Compare __comp)
2874 {
2875 // concept requirements
2876 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
2877 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
2878 __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
2879 typename iterator_traits<_InputIterator1>::value_type,
2880 typename iterator_traits<_InputIterator2>::value_type>)
2881 __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
2882 typename iterator_traits<_InputIterator2>::value_type,
2883 typename iterator_traits<_InputIterator1>::value_type>)
2884 __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp);
2885 __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp);
2886 __glibcxx_requires_irreflexive_pred2(__first1, __last1, __comp);
2887 __glibcxx_requires_irreflexive_pred2(__first2, __last2, __comp);
2888
2889 return std::__includes(__first1, __last1, __first2, __last2,
2890 __gnu_cxx::__ops::__iter_comp_iter(__comp));
2891 }
2892
2893 // nth_element
2894 // merge
2895 // set_difference
2896 // set_intersection
2897 // set_union
2898 // stable_sort
2899 // set_symmetric_difference
2900 // min_element
2901 // max_element
2902
2903 template<typename _BidirectionalIterator, typename _Compare>
2904 bool
2905 __next_permutation(_BidirectionalIterator __first,
2906 _BidirectionalIterator __last, _Compare __comp)
2907 {
2908 if (__first == __last)
2909 return false;
2910 _BidirectionalIterator __i = __first;
2911 ++__i;
2912 if (__i == __last)
2913 return false;
2914 __i = __last;
2915 --__i;
2916
2917 for(;;)
2918 {
2919 _BidirectionalIterator __ii = __i;
2920 --__i;
2921 if (__comp(__i, __ii))
2922 {
2923 _BidirectionalIterator __j = __last;
2924 while (!__comp(__i, --__j))
2925 {}
2926 std::iter_swap(__i, __j);
2927 std::__reverse(__ii, __last,
2928 std::__iterator_category(__first));
2929 return true;
2930 }
2931 if (__i == __first)
2932 {
2933 std::__reverse(__first, __last,
2934 std::__iterator_category(__first));
2935 return false;
2936 }
2937 }
2938 }
2939
2940 /**
2941 * @brief Permute range into the next @e dictionary ordering.
2942 * @ingroup sorting_algorithms
2943 * @param __first Start of range.
2944 * @param __last End of range.
2945 * @return False if wrapped to first permutation, true otherwise.
2946 *
2947 * Treats all permutations of the range as a set of @e dictionary sorted
2948 * sequences. Permutes the current sequence into the next one of this set.
2949 * Returns true if there are more sequences to generate. If the sequence
2950 * is the largest of the set, the smallest is generated and false returned.
2951 */
2952 template<typename _BidirectionalIterator>
2953 inline bool
2954 next_permutation(_BidirectionalIterator __first,
2955 _BidirectionalIterator __last)
2956 {
2957 // concept requirements
2958 __glibcxx_function_requires(_BidirectionalIteratorConcept<
2959 _BidirectionalIterator>)
2960 __glibcxx_function_requires(_LessThanComparableConcept<
2961 typename iterator_traits<_BidirectionalIterator>::value_type>)
2962 __glibcxx_requires_valid_range(__first, __last);
2963 __glibcxx_requires_irreflexive(__first, __last);
2964
2965 return std::__next_permutation
2966 (__first, __last, __gnu_cxx::__ops::__iter_less_iter());
2967 }
2968
2969 /**
2970 * @brief Permute range into the next @e dictionary ordering using
2971 * comparison functor.
2972 * @ingroup sorting_algorithms
2973 * @param __first Start of range.
2974 * @param __last End of range.
2975 * @param __comp A comparison functor.
2976 * @return False if wrapped to first permutation, true otherwise.
2977 *
2978 * Treats all permutations of the range [__first,__last) as a set of
2979 * @e dictionary sorted sequences ordered by @p __comp. Permutes the current
2980 * sequence into the next one of this set. Returns true if there are more
2981 * sequences to generate. If the sequence is the largest of the set, the
2982 * smallest is generated and false returned.
2983 */
2984 template<typename _BidirectionalIterator, typename _Compare>
2985 inline bool
2986 next_permutation(_BidirectionalIterator __first,
2987 _BidirectionalIterator __last, _Compare __comp)
2988 {
2989 // concept requirements
2990 __glibcxx_function_requires(_BidirectionalIteratorConcept<
2991 _BidirectionalIterator>)
2992 __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
2993 typename iterator_traits<_BidirectionalIterator>::value_type,
2994 typename iterator_traits<_BidirectionalIterator>::value_type>)
2995 __glibcxx_requires_valid_range(__first, __last);
2996 __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
2997
2998 return std::__next_permutation
2999 (__first, __last, __gnu_cxx::__ops::__iter_comp_iter(__comp));
3000 }
3001
3002 template<typename _BidirectionalIterator, typename _Compare>
3003 bool
3004 __prev_permutation(_BidirectionalIterator __first,
3005 _BidirectionalIterator __last, _Compare __comp)
3006 {
3007 if (__first == __last)
3008 return false;
3009 _BidirectionalIterator __i = __first;
3010 ++__i;
3011 if (__i == __last)
3012 return false;
3013 __i = __last;
3014 --__i;
3015
3016 for(;;)
3017 {
3018 _BidirectionalIterator __ii = __i;
3019 --__i;
3020 if (__comp(__ii, __i))
3021 {
3022 _BidirectionalIterator __j = __last;
3023 while (!__comp(--__j, __i))
3024 {}
3025 std::iter_swap(__i, __j);
3026 std::__reverse(__ii, __last,
3027 std::__iterator_category(__first));
3028 return true;
3029 }
3030 if (__i == __first)
3031 {
3032 std::__reverse(__first, __last,
3033 std::__iterator_category(__first));
3034 return false;
3035 }
3036 }
3037 }
3038
3039 /**
3040 * @brief Permute range into the previous @e dictionary ordering.
3041 * @ingroup sorting_algorithms
3042 * @param __first Start of range.
3043 * @param __last End of range.
3044 * @return False if wrapped to last permutation, true otherwise.
3045 *
3046 * Treats all permutations of the range as a set of @e dictionary sorted
3047 * sequences. Permutes the current sequence into the previous one of this
3048 * set. Returns true if there are more sequences to generate. If the
3049 * sequence is the smallest of the set, the largest is generated and false
3050 * returned.
3051 */
3052 template<typename _BidirectionalIterator>
3053 inline bool
3054 prev_permutation(_BidirectionalIterator __first,
3055 _BidirectionalIterator __last)
3056 {
3057 // concept requirements
3058 __glibcxx_function_requires(_BidirectionalIteratorConcept<
3059 _BidirectionalIterator>)
3060 __glibcxx_function_requires(_LessThanComparableConcept<
3061 typename iterator_traits<_BidirectionalIterator>::value_type>)
3062 __glibcxx_requires_valid_range(__first, __last);
3063 __glibcxx_requires_irreflexive(__first, __last);
3064
3065 return std::__prev_permutation(__first, __last,
3066 __gnu_cxx::__ops::__iter_less_iter());
3067 }
3068
3069 /**
3070 * @brief Permute range into the previous @e dictionary ordering using
3071 * comparison functor.
3072 * @ingroup sorting_algorithms
3073 * @param __first Start of range.
3074 * @param __last End of range.
3075 * @param __comp A comparison functor.
3076 * @return False if wrapped to last permutation, true otherwise.
3077 *
3078 * Treats all permutations of the range [__first,__last) as a set of
3079 * @e dictionary sorted sequences ordered by @p __comp. Permutes the current
3080 * sequence into the previous one of this set. Returns true if there are
3081 * more sequences to generate. If the sequence is the smallest of the set,
3082 * the largest is generated and false returned.
3083 */
3084 template<typename _BidirectionalIterator, typename _Compare>
3085 inline bool
3086 prev_permutation(_BidirectionalIterator __first,
3087 _BidirectionalIterator __last, _Compare __comp)
3088 {
3089 // concept requirements
3090 __glibcxx_function_requires(_BidirectionalIteratorConcept<
3091 _BidirectionalIterator>)
3092 __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
3093 typename iterator_traits<_BidirectionalIterator>::value_type,
3094 typename iterator_traits<_BidirectionalIterator>::value_type>)
3095 __glibcxx_requires_valid_range(__first, __last);
3096 __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
3097
3098 return std::__prev_permutation(__first, __last,
3099 __gnu_cxx::__ops::__iter_comp_iter(__comp));
3100 }
3101
3102 // replace
3103 // replace_if
3104
3105 template<typename _InputIterator, typename _OutputIterator,
3106 typename _Predicate, typename _Tp>
3107 _OutputIterator
3108 __replace_copy_if(_InputIterator __first, _InputIterator __last,
3109 _OutputIterator __result,
3110 _Predicate __pred, const _Tp& __new_value)
3111 {
3112 for (; __first != __last; ++__first, (void)++__result)
3113 if (__pred(__first))
3114 *__result = __new_value;
3115 else
3116 *__result = *__first;
3117 return __result;
3118 }
3119
3120 /**
3121 * @brief Copy a sequence, replacing each element of one value with another
3122 * value.
3123 * @param __first An input iterator.
3124 * @param __last An input iterator.
3125 * @param __result An output iterator.
3126 * @param __old_value The value to be replaced.
3127 * @param __new_value The replacement value.
3128 * @return The end of the output sequence, @p result+(last-first).
3129 *
3130 * Copies each element in the input range @p [__first,__last) to the
3131 * output range @p [__result,__result+(__last-__first)) replacing elements
3132 * equal to @p __old_value with @p __new_value.
3133 */
3134 template<typename _InputIterator, typename _OutputIterator, typename _Tp>
3135 inline _OutputIterator
3136 replace_copy(_InputIterator __first, _InputIterator __last,
3137 _OutputIterator __result,
3138 const _Tp& __old_value, const _Tp& __new_value)
3139 {
3140 // concept requirements
3141 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
3142 __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
3143 typename iterator_traits<_InputIterator>::value_type>)
3144 __glibcxx_function_requires(_EqualOpConcept<
3145 typename iterator_traits<_InputIterator>::value_type, _Tp>)
3146 __glibcxx_requires_valid_range(__first, __last);
3147
3148 return std::__replace_copy_if(__first, __last, __result,
3149 __gnu_cxx::__ops::__iter_equals_val(__old_value),
3150 __new_value);
3151 }
3152
3153 /**
3154 * @brief Copy a sequence, replacing each value for which a predicate
3155 * returns true with another value.
3156 * @ingroup mutating_algorithms
3157 * @param __first An input iterator.
3158 * @param __last An input iterator.
3159 * @param __result An output iterator.
3160 * @param __pred A predicate.
3161 * @param __new_value The replacement value.
3162 * @return The end of the output sequence, @p __result+(__last-__first).
3163 *
3164 * Copies each element in the range @p [__first,__last) to the range
3165 * @p [__result,__result+(__last-__first)) replacing elements for which
3166 * @p __pred returns true with @p __new_value.
3167 */
3168 template<typename _InputIterator, typename _OutputIterator,
3169 typename _Predicate, typename _Tp>
3170 inline _OutputIterator
3171 replace_copy_if(_InputIterator __first, _InputIterator __last,
3172 _OutputIterator __result,
3173 _Predicate __pred, const _Tp& __new_value)
3174 {
3175 // concept requirements
3176 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
3177 __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
3178 typename iterator_traits<_InputIterator>::value_type>)
3179 __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
3180 typename iterator_traits<_InputIterator>::value_type>)
3181 __glibcxx_requires_valid_range(__first, __last);
3182
3183 return std::__replace_copy_if(__first, __last, __result,
3184 __gnu_cxx::__ops::__pred_iter(__pred),
3185 __new_value);
3186 }
3187
3188 template<typename _InputIterator, typename _Predicate>
3189 typename iterator_traits<_InputIterator>::difference_type
3190 __count_if(_InputIterator __first, _InputIterator __last, _Predicate __pred)
3191 {
3192 typename iterator_traits<_InputIterator>::difference_type __n = 0;
3193 for (; __first != __last; ++__first)
3194 if (__pred(__first))
3195 ++__n;
3196 return __n;
3197 }
3198
3199#if __cplusplus >= 201103L
3200 /**
3201 * @brief Determines whether the elements of a sequence are sorted.
3202 * @ingroup sorting_algorithms
3203 * @param __first An iterator.
3204 * @param __last Another iterator.
3205 * @return True if the elements are sorted, false otherwise.
3206 */
3207 template<typename _ForwardIterator>
3208 inline bool
3209 is_sorted(_ForwardIterator __first, _ForwardIterator __last)
3210 { return std::is_sorted_until(__first, __last) == __last; }
3211
3212 /**
3213 * @brief Determines whether the elements of a sequence are sorted
3214 * according to a comparison functor.
3215 * @ingroup sorting_algorithms
3216 * @param __first An iterator.
3217 * @param __last Another iterator.
3218 * @param __comp A comparison functor.
3219 * @return True if the elements are sorted, false otherwise.
3220 */
3221 template<typename _ForwardIterator, typename _Compare>
3222 inline bool
3223 is_sorted(_ForwardIterator __first, _ForwardIterator __last,
3224 _Compare __comp)
3225 { return std::is_sorted_until(__first, __last, __comp) == __last; }
3226
3227 template<typename _ForwardIterator, typename _Compare>
3228 _ForwardIterator
3229 __is_sorted_until(_ForwardIterator __first, _ForwardIterator __last,
3230 _Compare __comp)
3231 {
3232 if (__first == __last)
3233 return __last;
3234
3235 _ForwardIterator __next = __first;
3236 for (++__next; __next != __last; __first = __next, (void)++__next)
3237 if (__comp(__next, __first))
3238 return __next;
3239 return __next;
3240 }
3241
3242 /**
3243 * @brief Determines the end of a sorted sequence.
3244 * @ingroup sorting_algorithms
3245 * @param __first An iterator.
3246 * @param __last Another iterator.
3247 * @return An iterator pointing to the last iterator i in [__first, __last)
3248 * for which the range [__first, i) is sorted.
3249 */
3250 template<typename _ForwardIterator>
3251 inline _ForwardIterator
3252 is_sorted_until(_ForwardIterator __first, _ForwardIterator __last)
3253 {
3254 // concept requirements
3255 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
3256 __glibcxx_function_requires(_LessThanComparableConcept<
3257 typename iterator_traits<_ForwardIterator>::value_type>)
3258 __glibcxx_requires_valid_range(__first, __last);
3259 __glibcxx_requires_irreflexive(__first, __last);
3260
3261 return std::__is_sorted_until(__first, __last,
3262 __gnu_cxx::__ops::__iter_less_iter());
3263 }
3264
3265 /**
3266 * @brief Determines the end of a sorted sequence using comparison functor.
3267 * @ingroup sorting_algorithms
3268 * @param __first An iterator.
3269 * @param __last Another iterator.
3270 * @param __comp A comparison functor.
3271 * @return An iterator pointing to the last iterator i in [__first, __last)
3272 * for which the range [__first, i) is sorted.
3273 */
3274 template<typename _ForwardIterator, typename _Compare>
3275 inline _ForwardIterator
3276 is_sorted_until(_ForwardIterator __first, _ForwardIterator __last,
3277 _Compare __comp)
3278 {
3279 // concept requirements
3280 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
3281 __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
3282 typename iterator_traits<_ForwardIterator>::value_type,
3283 typename iterator_traits<_ForwardIterator>::value_type>)
3284 __glibcxx_requires_valid_range(__first, __last);
3285 __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
3286
3287 return std::__is_sorted_until(__first, __last,
3288 __gnu_cxx::__ops::__iter_comp_iter(__comp));
3289 }
3290
3291 /**
3292 * @brief Determines min and max at once as an ordered pair.
3293 * @ingroup sorting_algorithms
3294 * @param __a A thing of arbitrary type.
3295 * @param __b Another thing of arbitrary type.
3296 * @return A pair(__b, __a) if __b is smaller than __a, pair(__a,
3297 * __b) otherwise.
3298 */
3299 template<typename _Tp>
3300 _GLIBCXX14_CONSTEXPR
3301 inline pair<const _Tp&, const _Tp&>
3302 minmax(const _Tp& __a, const _Tp& __b)
3303 {
3304 // concept requirements
3305 __glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
3306
3307 return __b < __a ? pair<const _Tp&, const _Tp&>(__b, __a)
3308 : pair<const _Tp&, const _Tp&>(__a, __b);
3309 }
3310
3311 /**
3312 * @brief Determines min and max at once as an ordered pair.
3313 * @ingroup sorting_algorithms
3314 * @param __a A thing of arbitrary type.
3315 * @param __b Another thing of arbitrary type.
3316 * @param __comp A @link comparison_functors comparison functor @endlink.
3317 * @return A pair(__b, __a) if __b is smaller than __a, pair(__a,
3318 * __b) otherwise.
3319 */
3320 template<typename _Tp, typename _Compare>
3321 _GLIBCXX14_CONSTEXPR
3322 inline pair<const _Tp&, const _Tp&>
3323 minmax(const _Tp& __a, const _Tp& __b, _Compare __comp)
3324 {
3325 return __comp(__b, __a) ? pair<const _Tp&, const _Tp&>(__b, __a)
3326 : pair<const _Tp&, const _Tp&>(__a, __b);
3327 }
3328
3329 template<typename _ForwardIterator, typename _Compare>
3330 _GLIBCXX14_CONSTEXPR
3331 pair<_ForwardIterator, _ForwardIterator>
3332 __minmax_element(_ForwardIterator __first, _ForwardIterator __last,
3333 _Compare __comp)
3334 {
3335 _ForwardIterator __next = __first;
3336 if (__first == __last
3337 || ++__next == __last)
3338 return std::make_pair(__first, __first);
3339
3340 _ForwardIterator __min{}, __max{};
3341 if (__comp(__next, __first))
3342 {
3343 __min = __next;
3344 __max = __first;
3345 }
3346 else
3347 {
3348 __min = __first;
3349 __max = __next;
3350 }
3351
3352 __first = __next;
3353 ++__first;
3354
3355 while (__first != __last)
3356 {
3357 __next = __first;
3358 if (++__next == __last)
3359 {
3360 if (__comp(__first, __min))
3361 __min = __first;
3362 else if (!__comp(__first, __max))
3363 __max = __first;
3364 break;
3365 }
3366
3367 if (__comp(__next, __first))
3368 {
3369 if (__comp(__next, __min))
3370 __min = __next;
3371 if (!__comp(__first, __max))
3372 __max = __first;
3373 }
3374 else
3375 {
3376 if (__comp(__first, __min))
3377 __min = __first;
3378 if (!__comp(__next, __max))
3379 __max = __next;
3380 }
3381
3382 __first = __next;
3383 ++__first;
3384 }
3385
3386 return std::make_pair(__min, __max);
3387 }
3388
3389 /**
3390 * @brief Return a pair of iterators pointing to the minimum and maximum
3391 * elements in a range.
3392 * @ingroup sorting_algorithms
3393 * @param __first Start of range.
3394 * @param __last End of range.
3395 * @return make_pair(m, M), where m is the first iterator i in
3396 * [__first, __last) such that no other element in the range is
3397 * smaller, and where M is the last iterator i in [__first, __last)
3398 * such that no other element in the range is larger.
3399 */
3400 template<typename _ForwardIterator>
3401 _GLIBCXX14_CONSTEXPR
3402 inline pair<_ForwardIterator, _ForwardIterator>
3403 minmax_element(_ForwardIterator __first, _ForwardIterator __last)
3404 {
3405 // concept requirements
3406 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
3407 __glibcxx_function_requires(_LessThanComparableConcept<
3408 typename iterator_traits<_ForwardIterator>::value_type>)
3409 __glibcxx_requires_valid_range(__first, __last);
3410 __glibcxx_requires_irreflexive(__first, __last);
3411
3412 return std::__minmax_element(__first, __last,
3413 __gnu_cxx::__ops::__iter_less_iter());
3414 }
3415
3416 /**
3417 * @brief Return a pair of iterators pointing to the minimum and maximum
3418 * elements in a range.
3419 * @ingroup sorting_algorithms
3420 * @param __first Start of range.
3421 * @param __last End of range.
3422 * @param __comp Comparison functor.
3423 * @return make_pair(m, M), where m is the first iterator i in
3424 * [__first, __last) such that no other element in the range is
3425 * smaller, and where M is the last iterator i in [__first, __last)
3426 * such that no other element in the range is larger.
3427 */
3428 template<typename _ForwardIterator, typename _Compare>
3429 _GLIBCXX14_CONSTEXPR
3430 inline pair<_ForwardIterator, _ForwardIterator>
3431 minmax_element(_ForwardIterator __first, _ForwardIterator __last,
3432 _Compare __comp)
3433 {
3434 // concept requirements
3435 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
3436 __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
3437 typename iterator_traits<_ForwardIterator>::value_type,
3438 typename iterator_traits<_ForwardIterator>::value_type>)
3439 __glibcxx_requires_valid_range(__first, __last);
3440 __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
3441
3442 return std::__minmax_element(__first, __last,
3443 __gnu_cxx::__ops::__iter_comp_iter(__comp));
3444 }
3445
3446 // N2722 + DR 915.
3447 template<typename _Tp>
3448 _GLIBCXX14_CONSTEXPR
3449 inline _Tp
3450 min(initializer_list<_Tp> __l)
3451 { return *std::min_element(__l.begin(), __l.end()); }
3452
3453 template<typename _Tp, typename _Compare>
3454 _GLIBCXX14_CONSTEXPR
3455 inline _Tp
3456 min(initializer_list<_Tp> __l, _Compare __comp)
3457 { return *std::min_element(__l.begin(), __l.end(), __comp); }
3458
3459 template<typename _Tp>
3460 _GLIBCXX14_CONSTEXPR
3461 inline _Tp
3462 max(initializer_list<_Tp> __l)
3463 { return *std::max_element(__l.begin(), __l.end()); }
3464
3465 template<typename _Tp, typename _Compare>
3466 _GLIBCXX14_CONSTEXPR
3467 inline _Tp
3468 max(initializer_list<_Tp> __l, _Compare __comp)
3469 { return *std::max_element(__l.begin(), __l.end(), __comp); }
3470
3471 template<typename _Tp>
3472 _GLIBCXX14_CONSTEXPR
3473 inline pair<_Tp, _Tp>
3474 minmax(initializer_list<_Tp> __l)
3475 {
3476 pair<const _Tp*, const _Tp*> __p =
3477 std::minmax_element(__l.begin(), __l.end());
3478 return std::make_pair(*__p.first, *__p.second);
3479 }
3480
3481 template<typename _Tp, typename _Compare>
3482 _GLIBCXX14_CONSTEXPR
3483 inline pair<_Tp, _Tp>
3484 minmax(initializer_list<_Tp> __l, _Compare __comp)
3485 {
3486 pair<const _Tp*, const _Tp*> __p =
3487 std::minmax_element(__l.begin(), __l.end(), __comp);
3488 return std::make_pair(*__p.first, *__p.second);
3489 }
3490
3491 template<typename _ForwardIterator1, typename _ForwardIterator2,
3492 typename _BinaryPredicate>
3493 bool
3494 __is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
3495 _ForwardIterator2 __first2, _BinaryPredicate __pred)
3496 {
3497 // Efficiently compare identical prefixes: O(N) if sequences
3498 // have the same elements in the same order.
3499 for (; __first1 != __last1; ++__first1, (void)++__first2)
3500 if (!__pred(__first1, __first2))
3501 break;
3502
3503 if (__first1 == __last1)
3504 return true;
3505
3506 // Establish __last2 assuming equal ranges by iterating over the
3507 // rest of the list.
3508 _ForwardIterator2 __last2 = __first2;
3509 std::advance(__last2, std::distance(__first1, __last1));
3510 for (_ForwardIterator1 __scan = __first1; __scan != __last1; ++__scan)
3511 {
3512 if (__scan != std::__find_if(__first1, __scan,
3513 __gnu_cxx::__ops::__iter_comp_iter(__pred, __scan)))
3514 continue; // We've seen this one before.
3515
3516 auto __matches
3517 = std::__count_if(__first2, __last2,
3518 __gnu_cxx::__ops::__iter_comp_iter(__pred, __scan));
3519 if (0 == __matches ||
3520 std::__count_if(__scan, __last1,
3521 __gnu_cxx::__ops::__iter_comp_iter(__pred, __scan))
3522 != __matches)
3523 return false;
3524 }
3525 return true;
3526 }
3527
3528 /**
3529 * @brief Checks whether a permutation of the second sequence is equal
3530 * to the first sequence.
3531 * @ingroup non_mutating_algorithms
3532 * @param __first1 Start of first range.
3533 * @param __last1 End of first range.
3534 * @param __first2 Start of second range.
3535 * @return true if there exists a permutation of the elements in the range
3536 * [__first2, __first2 + (__last1 - __first1)), beginning with
3537 * ForwardIterator2 begin, such that equal(__first1, __last1, begin)
3538 * returns true; otherwise, returns false.
3539 */
3540 template<typename _ForwardIterator1, typename _ForwardIterator2>
3541 inline bool
3542 is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
3543 _ForwardIterator2 __first2)
3544 {
3545 // concept requirements
3546 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
3547 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
3548 __glibcxx_function_requires(_EqualOpConcept<
3549 typename iterator_traits<_ForwardIterator1>::value_type,
3550 typename iterator_traits<_ForwardIterator2>::value_type>)
3551 __glibcxx_requires_valid_range(__first1, __last1);
3552
3553 return std::__is_permutation(__first1, __last1, __first2,
3554 __gnu_cxx::__ops::__iter_equal_to_iter());
3555 }
3556
3557 /**
3558 * @brief Checks whether a permutation of the second sequence is equal
3559 * to the first sequence.
3560 * @ingroup non_mutating_algorithms
3561 * @param __first1 Start of first range.
3562 * @param __last1 End of first range.
3563 * @param __first2 Start of second range.
3564 * @param __pred A binary predicate.
3565 * @return true if there exists a permutation of the elements in
3566 * the range [__first2, __first2 + (__last1 - __first1)),
3567 * beginning with ForwardIterator2 begin, such that
3568 * equal(__first1, __last1, __begin, __pred) returns true;
3569 * otherwise, returns false.
3570 */
3571 template<typename _ForwardIterator1, typename _ForwardIterator2,
3572 typename _BinaryPredicate>
3573 inline bool
3574 is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
3575 _ForwardIterator2 __first2, _BinaryPredicate __pred)
3576 {
3577 // concept requirements
3578 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
3579 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
3580 __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
3581 typename iterator_traits<_ForwardIterator1>::value_type,
3582 typename iterator_traits<_ForwardIterator2>::value_type>)
3583 __glibcxx_requires_valid_range(__first1, __last1);
3584
3585 return std::__is_permutation(__first1, __last1, __first2,
3586 __gnu_cxx::__ops::__iter_comp_iter(__pred));
3587 }
3588
3589#if __cplusplus > 201103L
3590 template<typename _ForwardIterator1, typename _ForwardIterator2,
3591 typename _BinaryPredicate>
3592 bool
3593 __is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
3594 _ForwardIterator2 __first2, _ForwardIterator2 __last2,
3595 _BinaryPredicate __pred)
3596 {
3597 using _Cat1
3598 = typename iterator_traits<_ForwardIterator1>::iterator_category;
3599 using _Cat2
3600 = typename iterator_traits<_ForwardIterator2>::iterator_category;
3601 using _It1_is_RA = is_same<_Cat1, random_access_iterator_tag>;
3602 using _It2_is_RA = is_same<_Cat2, random_access_iterator_tag>;
3603 constexpr bool __ra_iters = _It1_is_RA() && _It2_is_RA();
3604 if (__ra_iters)
3605 {
3606 auto __d1 = std::distance(__first1, __last1);
3607 auto __d2 = std::distance(__first2, __last2);
3608 if (__d1 != __d2)
3609 return false;
3610 }
3611
3612 // Efficiently compare identical prefixes: O(N) if sequences
3613 // have the same elements in the same order.
3614 for (; __first1 != __last1 && __first2 != __last2;
3615 ++__first1, (void)++__first2)
3616 if (!__pred(__first1, __first2))
3617 break;
3618
3619 if (__ra_iters)
3620 {
3621 if (__first1 == __last1)
3622 return true;
3623 }
3624 else
3625 {
3626 auto __d1 = std::distance(__first1, __last1);
3627 auto __d2 = std::distance(__first2, __last2);
3628 if (__d1 == 0 && __d2 == 0)
3629 return true;
3630 if (__d1 != __d2)
3631 return false;
3632 }
3633
3634 for (_ForwardIterator1 __scan = __first1; __scan != __last1; ++__scan)
3635 {
3636 if (__scan != std::__find_if(__first1, __scan,
3637 __gnu_cxx::__ops::__iter_comp_iter(__pred, __scan)))
3638 continue; // We've seen this one before.
3639
3640 auto __matches = std::__count_if(__first2, __last2,
3641 __gnu_cxx::__ops::__iter_comp_iter(__pred, __scan));
3642 if (0 == __matches
3643 || std::__count_if(__scan, __last1,
3644 __gnu_cxx::__ops::__iter_comp_iter(__pred, __scan))
3645 != __matches)
3646 return false;
3647 }
3648 return true;
3649 }
3650
3651 /**
3652 * @brief Checks whether a permutaion of the second sequence is equal
3653 * to the first sequence.
3654 * @ingroup non_mutating_algorithms
3655 * @param __first1 Start of first range.
3656 * @param __last1 End of first range.
3657 * @param __first2 Start of second range.
3658 * @param __last2 End of first range.
3659 * @return true if there exists a permutation of the elements in the range
3660 * [__first2, __last2), beginning with ForwardIterator2 begin,
3661 * such that equal(__first1, __last1, begin) returns true;
3662 * otherwise, returns false.
3663 */
3664 template<typename _ForwardIterator1, typename _ForwardIterator2>
3665 inline bool
3666 is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
3667 _ForwardIterator2 __first2, _ForwardIterator2 __last2)
3668 {
3669 __glibcxx_requires_valid_range(__first1, __last1);
3670 __glibcxx_requires_valid_range(__first2, __last2);
3671
3672 return
3673 std::__is_permutation(__first1, __last1, __first2, __last2,
3674 __gnu_cxx::__ops::__iter_equal_to_iter());
3675 }
3676
3677 /**
3678 * @brief Checks whether a permutation of the second sequence is equal
3679 * to the first sequence.
3680 * @ingroup non_mutating_algorithms
3681 * @param __first1 Start of first range.
3682 * @param __last1 End of first range.
3683 * @param __first2 Start of second range.
3684 * @param __last2 End of first range.
3685 * @param __pred A binary predicate.
3686 * @return true if there exists a permutation of the elements in the range
3687 * [__first2, __last2), beginning with ForwardIterator2 begin,
3688 * such that equal(__first1, __last1, __begin, __pred) returns true;
3689 * otherwise, returns false.
3690 */
3691 template<typename _ForwardIterator1, typename _ForwardIterator2,
3692 typename _BinaryPredicate>
3693 inline bool
3694 is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
3695 _ForwardIterator2 __first2, _ForwardIterator2 __last2,
3696 _BinaryPredicate __pred)
3697 {
3698 __glibcxx_requires_valid_range(__first1, __last1);
3699 __glibcxx_requires_valid_range(__first2, __last2);
3700
3701 return std::__is_permutation(__first1, __last1, __first2, __last2,
3702 __gnu_cxx::__ops::__iter_comp_iter(__pred));
3703 }
3704
3705#if __cplusplus > 201402L
3706
3707#define __cpp_lib_clamp 201603
3708
3709 /**
3710 * @brief Returns the value clamped between lo and hi.
3711 * @ingroup sorting_algorithms
3712 * @param __val A value of arbitrary type.
3713 * @param __lo A lower limit of arbitrary type.
3714 * @param __hi An upper limit of arbitrary type.
3715 * @return max(__val, __lo) if __val < __hi or min(__val, __hi) otherwise.
3716 */
3717 template<typename _Tp>
3718 constexpr const _Tp&
3719 clamp(const _Tp& __val, const _Tp& __lo, const _Tp& __hi)
3720 {
3721 __glibcxx_assert(!(__hi < __lo));
3722 return (__val < __lo) ? __lo : (__hi < __val) ? __hi : __val;
3723 }
3724
3725 /**
3726 * @brief Returns the value clamped between lo and hi.
3727 * @ingroup sorting_algorithms
3728 * @param __val A value of arbitrary type.
3729 * @param __lo A lower limit of arbitrary type.
3730 * @param __hi An upper limit of arbitrary type.
3731 * @param __comp A comparison functor.
3732 * @return max(__val, __lo, __comp) if __comp(__val, __hi)
3733 * or min(__val, __hi, __comp) otherwise.
3734 */
3735 template<typename _Tp, typename _Compare>
3736 constexpr const _Tp&
3737 clamp(const _Tp& __val, const _Tp& __lo, const _Tp& __hi, _Compare __comp)
3738 {
3739 __glibcxx_assert(!__comp(__hi, __lo));
3740 return __comp(__val, __lo) ? __lo : __comp(__hi, __val) ? __hi : __val;
3741 }
3742#endif // C++17
3743#endif // C++14
3744
3745#ifdef _GLIBCXX_USE_C99_STDINT_TR1
3746 /**
3747 * @brief Generate two uniformly distributed integers using a
3748 * single distribution invocation.
3749 * @param __b0 The upper bound for the first integer.
3750 * @param __b1 The upper bound for the second integer.
3751 * @param __g A UniformRandomBitGenerator.
3752 * @return A pair (i, j) with i and j uniformly distributed
3753 * over [0, __b0) and [0, __b1), respectively.
3754 *
3755 * Requires: __b0 * __b1 <= __g.max() - __g.min().
3756 *
3757 * Using uniform_int_distribution with a range that is very
3758 * small relative to the range of the generator ends up wasting
3759 * potentially expensively generated randomness, since
3760 * uniform_int_distribution does not store leftover randomness
3761 * between invocations.
3762 *
3763 * If we know we want two integers in ranges that are sufficiently
3764 * small, we can compose the ranges, use a single distribution
3765 * invocation, and significantly reduce the waste.
3766 */
3767 template<typename _IntType, typename _UniformRandomBitGenerator>
3768 pair<_IntType, _IntType>
3769 __gen_two_uniform_ints(_IntType __b0, _IntType __b1,
3770 _UniformRandomBitGenerator&& __g)
3771 {
3772 _IntType __x
3773 = uniform_int_distribution<_IntType>{0, (__b0 * __b1) - 1}(__g);
3774 return std::make_pair(__x / __b1, __x % __b1);
3775 }
3776
3777 /**
3778 * @brief Shuffle the elements of a sequence using a uniform random
3779 * number generator.
3780 * @ingroup mutating_algorithms
3781 * @param __first A forward iterator.
3782 * @param __last A forward iterator.
3783 * @param __g A UniformRandomNumberGenerator (26.5.1.3).
3784 * @return Nothing.
3785 *
3786 * Reorders the elements in the range @p [__first,__last) using @p __g to
3787 * provide random numbers.
3788 */
3789 template<typename _RandomAccessIterator,
3790 typename _UniformRandomNumberGenerator>
3791 void
3792 shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last,
3793 _UniformRandomNumberGenerator&& __g)
3794 {
3795 // concept requirements
3796 __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
3797 _RandomAccessIterator>)
3798 __glibcxx_requires_valid_range(__first, __last);
3799
3800 if (__first == __last)
3801 return;
3802
3803 typedef typename iterator_traits<_RandomAccessIterator>::difference_type
3804 _DistanceType;
3805
3806 typedef typename std::make_unsigned<_DistanceType>::type __ud_type;
3807 typedef typename std::uniform_int_distribution<__ud_type> __distr_type;
3808 typedef typename __distr_type::param_type __p_type;
3809
3810 typedef typename remove_reference<_UniformRandomNumberGenerator>::type
3811 _Gen;
3812 typedef typename common_type<typename _Gen::result_type, __ud_type>::type
3813 __uc_type;
3814
3815 const __uc_type __urngrange = __g.max() - __g.min();
3816 const __uc_type __urange = __uc_type(__last - __first);
3817
3818 if (__urngrange / __urange >= __urange)
3819 // I.e. (__urngrange >= __urange * __urange) but without wrap issues.
3820 {
3821 _RandomAccessIterator __i = __first + 1;
3822
3823 // Since we know the range isn't empty, an even number of elements
3824 // means an uneven number of elements /to swap/, in which case we
3825 // do the first one up front:
3826
3827 if ((__urange % 2) == 0)
3828 {
3829 __distr_type __d{0, 1};
3830 std::iter_swap(__i++, __first + __d(__g));
3831 }
3832
3833 // Now we know that __last - __i is even, so we do the rest in pairs,
3834 // using a single distribution invocation to produce swap positions
3835 // for two successive elements at a time:
3836
3837 while (__i != __last)
3838 {
3839 const __uc_type __swap_range = __uc_type(__i - __first) + 1;
3840
3841 const pair<__uc_type, __uc_type> __pospos =
3842 __gen_two_uniform_ints(__swap_range, __swap_range + 1, __g);
3843
3844 std::iter_swap(__i++, __first + __pospos.first);
3845 std::iter_swap(__i++, __first + __pospos.second);
3846 }
3847
3848 return;
3849 }
3850
3851 __distr_type __d;
3852
3853 for (_RandomAccessIterator __i = __first + 1; __i != __last; ++__i)
3854 std::iter_swap(__i, __first + __d(__g, __p_type(0, __i - __first)));
3855 }
3856#endif
3857
3858#endif // C++11
3859
3860_GLIBCXX_BEGIN_NAMESPACE_ALGO
3861
3862 /**
3863 * @brief Apply a function to every element of a sequence.
3864 * @ingroup non_mutating_algorithms
3865 * @param __first An input iterator.
3866 * @param __last An input iterator.
3867 * @param __f A unary function object.
3868 * @return @p __f
3869 *
3870 * Applies the function object @p __f to each element in the range
3871 * @p [first,last). @p __f must not modify the order of the sequence.
3872 * If @p __f has a return value it is ignored.
3873 */
3874 template<typename _InputIterator, typename _Function>
3875 _Function
3876 for_each(_InputIterator __first, _InputIterator __last, _Function __f)
3877 {
3878 // concept requirements
3879 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
3880 __glibcxx_requires_valid_range(__first, __last);
3881 for (; __first != __last; ++__first)
3882 __f(*__first);
3883 return __f; // N.B. [alg.foreach] says std::move(f) but it's redundant.
3884 }
3885
3886#if __cplusplus >= 201703L
3887 /**
3888 * @brief Apply a function to every element of a sequence.
3889 * @ingroup non_mutating_algorithms
3890 * @param __first An input iterator.
3891 * @param __n A value convertible to an integer.
3892 * @param __f A unary function object.
3893 * @return `__first+__n`
3894 *
3895 * Applies the function object `__f` to each element in the range
3896 * `[first, first+n)`. `__f` must not modify the order of the sequence.
3897 * If `__f` has a return value it is ignored.
3898 */
3899 template<typename _InputIterator, typename _Size, typename _Function>
3900 _InputIterator
3901 for_each_n(_InputIterator __first, _Size __n, _Function __f)
3902 {
3903 typename iterator_traits<_InputIterator>::difference_type __n2 = __n;
3904 using _Cat = typename iterator_traits<_InputIterator>::iterator_category;
3905 if constexpr (is_base_of_v<random_access_iterator_tag, _Cat>)
3906 {
3907 if (__n2 <= 0)
3908 return __first;
3909 auto __last = __first + __n2;
3910 std::for_each(__first, __last, std::move(__f));
3911 return __last;
3912 }
3913 else
3914 {
3915 while (__n2-->0)
3916 {
3917 __f(*__first);
3918 ++__first;
3919 }
3920 return __first;
3921 }
3922 }
3923#endif // C++17
3924
3925 /**
3926 * @brief Find the first occurrence of a value in a sequence.
3927 * @ingroup non_mutating_algorithms
3928 * @param __first An input iterator.
3929 * @param __last An input iterator.
3930 * @param __val The value to find.
3931 * @return The first iterator @c i in the range @p [__first,__last)
3932 * such that @c *i == @p __val, or @p __last if no such iterator exists.
3933 */
3934 template<typename _InputIterator, typename _Tp>
3935 inline _InputIterator
3936 find(_InputIterator __first, _InputIterator __last,
3937 const _Tp& __val)
3938 {
3939 // concept requirements
3940 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
3941 __glibcxx_function_requires(_EqualOpConcept<
3942 typename iterator_traits<_InputIterator>::value_type, _Tp>)
3943 __glibcxx_requires_valid_range(__first, __last);
3944 return std::__find_if(__first, __last,
3945 __gnu_cxx::__ops::__iter_equals_val(__val));
3946 }
3947
3948 /**
3949 * @brief Find the first element in a sequence for which a
3950 * predicate is true.
3951 * @ingroup non_mutating_algorithms
3952 * @param __first An input iterator.
3953 * @param __last An input iterator.
3954 * @param __pred A predicate.
3955 * @return The first iterator @c i in the range @p [__first,__last)
3956 * such that @p __pred(*i) is true, or @p __last if no such iterator exists.
3957 */
3958 template<typename _InputIterator, typename _Predicate>
3959 inline _InputIterator
3960 find_if(_InputIterator __first, _InputIterator __last,
3961 _Predicate __pred)
3962 {
3963 // concept requirements
3964 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
3965 __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
3966 typename iterator_traits<_InputIterator>::value_type>)
3967 __glibcxx_requires_valid_range(__first, __last);
3968
3969 return std::__find_if(__first, __last,
3970 __gnu_cxx::__ops::__pred_iter(__pred));
3971 }
3972
3973 /**
3974 * @brief Find element from a set in a sequence.
3975 * @ingroup non_mutating_algorithms
3976 * @param __first1 Start of range to search.
3977 * @param __last1 End of range to search.
3978 * @param __first2 Start of match candidates.
3979 * @param __last2 End of match candidates.
3980 * @return The first iterator @c i in the range
3981 * @p [__first1,__last1) such that @c *i == @p *(i2) such that i2 is an
3982 * iterator in [__first2,__last2), or @p __last1 if no such iterator exists.
3983 *
3984 * Searches the range @p [__first1,__last1) for an element that is
3985 * equal to some element in the range [__first2,__last2). If
3986 * found, returns an iterator in the range [__first1,__last1),
3987 * otherwise returns @p __last1.
3988 */
3989 template<typename _InputIterator, typename _ForwardIterator>
3990 _InputIterator
3991 find_first_of(_InputIterator __first1, _InputIterator __last1,
3992 _ForwardIterator __first2, _ForwardIterator __last2)
3993 {
3994 // concept requirements
3995 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
3996 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
3997 __glibcxx_function_requires(_EqualOpConcept<
3998 typename iterator_traits<_InputIterator>::value_type,
3999 typename iterator_traits<_ForwardIterator>::value_type>)
4000 __glibcxx_requires_valid_range(__first1, __last1);
4001 __glibcxx_requires_valid_range(__first2, __last2);
4002
4003 for (; __first1 != __last1; ++__first1)
4004 for (_ForwardIterator __iter = __first2; __iter != __last2; ++__iter)
4005 if (*__first1 == *__iter)
4006 return __first1;
4007 return __last1;
4008 }
4009
4010 /**
4011 * @brief Find element from a set in a sequence using a predicate.
4012 * @ingroup non_mutating_algorithms
4013 * @param __first1 Start of range to search.
4014 * @param __last1 End of range to search.
4015 * @param __first2 Start of match candidates.
4016 * @param __last2 End of match candidates.
4017 * @param __comp Predicate to use.
4018 * @return The first iterator @c i in the range
4019 * @p [__first1,__last1) such that @c comp(*i, @p *(i2)) is true
4020 * and i2 is an iterator in [__first2,__last2), or @p __last1 if no
4021 * such iterator exists.
4022 *
4023
4024 * Searches the range @p [__first1,__last1) for an element that is
4025 * equal to some element in the range [__first2,__last2). If
4026 * found, returns an iterator in the range [__first1,__last1),
4027 * otherwise returns @p __last1.
4028 */
4029 template<typename _InputIterator, typename _ForwardIterator,
4030 typename _BinaryPredicate>
4031 _InputIterator
4032 find_first_of(_InputIterator __first1, _InputIterator __last1,
4033 _ForwardIterator __first2, _ForwardIterator __last2,
4034 _BinaryPredicate __comp)
4035 {
4036 // concept requirements
4037 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
4038 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
4039 __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
4040 typename iterator_traits<_InputIterator>::value_type,
4041 typename iterator_traits<_ForwardIterator>::value_type>)
4042 __glibcxx_requires_valid_range(__first1, __last1);
4043 __glibcxx_requires_valid_range(__first2, __last2);
4044
4045 for (; __first1 != __last1; ++__first1)
4046 for (_ForwardIterator __iter = __first2; __iter != __last2; ++__iter)
4047 if (__comp(*__first1, *__iter))
4048 return __first1;
4049 return __last1;
4050 }
4051
4052 /**
4053 * @brief Find two adjacent values in a sequence that are equal.
4054 * @ingroup non_mutating_algorithms
4055 * @param __first A forward iterator.
4056 * @param __last A forward iterator.
4057 * @return The first iterator @c i such that @c i and @c i+1 are both
4058 * valid iterators in @p [__first,__last) and such that @c *i == @c *(i+1),
4059 * or @p __last if no such iterator exists.
4060 */
4061 template<typename _ForwardIterator>
4062 inline _ForwardIterator
4063 adjacent_find(_ForwardIterator __first, _ForwardIterator __last)
4064 {
4065 // concept requirements
4066 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
4067 __glibcxx_function_requires(_EqualityComparableConcept<
4068 typename iterator_traits<_ForwardIterator>::value_type>)
4069 __glibcxx_requires_valid_range(__first, __last);
4070
4071 return std::__adjacent_find(__first, __last,
4072 __gnu_cxx::__ops::__iter_equal_to_iter());
4073 }
4074
4075 /**
4076 * @brief Find two adjacent values in a sequence using a predicate.
4077 * @ingroup non_mutating_algorithms
4078 * @param __first A forward iterator.
4079 * @param __last A forward iterator.
4080 * @param __binary_pred A binary predicate.
4081 * @return The first iterator @c i such that @c i and @c i+1 are both
4082 * valid iterators in @p [__first,__last) and such that
4083 * @p __binary_pred(*i,*(i+1)) is true, or @p __last if no such iterator
4084 * exists.
4085 */
4086 template<typename _ForwardIterator, typename _BinaryPredicate>
4087 inline _ForwardIterator
4088 adjacent_find(_ForwardIterator __first, _ForwardIterator __last,
4089 _BinaryPredicate __binary_pred)
4090 {
4091 // concept requirements
4092 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
4093 __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
4094 typename iterator_traits<_ForwardIterator>::value_type,
4095 typename iterator_traits<_ForwardIterator>::value_type>)
4096 __glibcxx_requires_valid_range(__first, __last);
4097
4098 return std::__adjacent_find(__first, __last,
4099 __gnu_cxx::__ops::__iter_comp_iter(__binary_pred));
4100 }
4101
4102 /**
4103 * @brief Count the number of copies of a value in a sequence.
4104 * @ingroup non_mutating_algorithms
4105 * @param __first An input iterator.
4106 * @param __last An input iterator.
4107 * @param __value The value to be counted.
4108 * @return The number of iterators @c i in the range @p [__first,__last)
4109 * for which @c *i == @p __value
4110 */
4111 template<typename _InputIterator, typename _Tp>
4112 inline typename iterator_traits<_InputIterator>::difference_type
4113 count(_InputIterator __first, _InputIterator __last, const _Tp& __value)
4114 {
4115 // concept requirements
4116 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
4117 __glibcxx_function_requires(_EqualOpConcept<
4118 typename iterator_traits<_InputIterator>::value_type, _Tp>)
4119 __glibcxx_requires_valid_range(__first, __last);
4120
4121 return std::__count_if(__first, __last,
4122 __gnu_cxx::__ops::__iter_equals_val(__value));
4123 }
4124
4125 /**
4126 * @brief Count the elements of a sequence for which a predicate is true.
4127 * @ingroup non_mutating_algorithms
4128 * @param __first An input iterator.
4129 * @param __last An input iterator.
4130 * @param __pred A predicate.
4131 * @return The number of iterators @c i in the range @p [__first,__last)
4132 * for which @p __pred(*i) is true.
4133 */
4134 template<typename _InputIterator, typename _Predicate>
4135 inline typename iterator_traits<_InputIterator>::difference_type
4136 count_if(_InputIterator __first, _InputIterator __last, _Predicate __pred)
4137 {
4138 // concept requirements
4139 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
4140 __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
4141 typename iterator_traits<_InputIterator>::value_type>)
4142 __glibcxx_requires_valid_range(__first, __last);
4143
4144 return std::__count_if(__first, __last,
4145 __gnu_cxx::__ops::__pred_iter(__pred));
4146 }
4147
4148 /**
4149 * @brief Search a sequence for a matching sub-sequence.
4150 * @ingroup non_mutating_algorithms
4151 * @param __first1 A forward iterator.
4152 * @param __last1 A forward iterator.
4153 * @param __first2 A forward iterator.
4154 * @param __last2 A forward iterator.
4155 * @return The first iterator @c i in the range @p
4156 * [__first1,__last1-(__last2-__first2)) such that @c *(i+N) == @p
4157 * *(__first2+N) for each @c N in the range @p
4158 * [0,__last2-__first2), or @p __last1 if no such iterator exists.
4159 *
4160 * Searches the range @p [__first1,__last1) for a sub-sequence that
4161 * compares equal value-by-value with the sequence given by @p
4162 * [__first2,__last2) and returns an iterator to the first element
4163 * of the sub-sequence, or @p __last1 if the sub-sequence is not
4164 * found.
4165 *
4166 * Because the sub-sequence must lie completely within the range @p
4167 * [__first1,__last1) it must start at a position less than @p
4168 * __last1-(__last2-__first2) where @p __last2-__first2 is the
4169 * length of the sub-sequence.
4170 *
4171 * This means that the returned iterator @c i will be in the range
4172 * @p [__first1,__last1-(__last2-__first2))
4173 */
4174 template<typename _ForwardIterator1, typename _ForwardIterator2>
4175 inline _ForwardIterator1
4176 search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
4177 _ForwardIterator2 __first2, _ForwardIterator2 __last2)
4178 {
4179 // concept requirements
4180 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
4181 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
4182 __glibcxx_function_requires(_EqualOpConcept<
4183 typename iterator_traits<_ForwardIterator1>::value_type,
4184 typename iterator_traits<_ForwardIterator2>::value_type>)
4185 __glibcxx_requires_valid_range(__first1, __last1);
4186 __glibcxx_requires_valid_range(__first2, __last2);
4187
4188 return std::__search(__first1, __last1, __first2, __last2,
4189 __gnu_cxx::__ops::__iter_equal_to_iter());
4190 }
4191
4192 /**
4193 * @brief Search a sequence for a matching sub-sequence using a predicate.
4194 * @ingroup non_mutating_algorithms
4195 * @param __first1 A forward iterator.
4196 * @param __last1 A forward iterator.
4197 * @param __first2 A forward iterator.
4198 * @param __last2 A forward iterator.
4199 * @param __predicate A binary predicate.
4200 * @return The first iterator @c i in the range
4201 * @p [__first1,__last1-(__last2-__first2)) such that
4202 * @p __predicate(*(i+N),*(__first2+N)) is true for each @c N in the range
4203 * @p [0,__last2-__first2), or @p __last1 if no such iterator exists.
4204 *
4205 * Searches the range @p [__first1,__last1) for a sub-sequence that
4206 * compares equal value-by-value with the sequence given by @p
4207 * [__first2,__last2), using @p __predicate to determine equality,
4208 * and returns an iterator to the first element of the
4209 * sub-sequence, or @p __last1 if no such iterator exists.
4210 *
4211 * @see search(_ForwardIter1, _ForwardIter1, _ForwardIter2, _ForwardIter2)
4212 */
4213 template<typename _ForwardIterator1, typename _ForwardIterator2,
4214 typename _BinaryPredicate>
4215 inline _ForwardIterator1
4216 search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
4217 _ForwardIterator2 __first2, _ForwardIterator2 __last2,
4218 _BinaryPredicate __predicate)
4219 {
4220 // concept requirements
4221 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
4222 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
4223 __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
4224 typename iterator_traits<_ForwardIterator1>::value_type,
4225 typename iterator_traits<_ForwardIterator2>::value_type>)
4226 __glibcxx_requires_valid_range(__first1, __last1);
4227 __glibcxx_requires_valid_range(__first2, __last2);
4228
4229 return std::__search(__first1, __last1, __first2, __last2,
4230 __gnu_cxx::__ops::__iter_comp_iter(__predicate));
4231 }
4232
4233 /**
4234 * @brief Search a sequence for a number of consecutive values.
4235 * @ingroup non_mutating_algorithms
4236 * @param __first A forward iterator.
4237 * @param __last A forward iterator.
4238 * @param __count The number of consecutive values.
4239 * @param __val The value to find.
4240 * @return The first iterator @c i in the range @p
4241 * [__first,__last-__count) such that @c *(i+N) == @p __val for
4242 * each @c N in the range @p [0,__count), or @p __last if no such
4243 * iterator exists.
4244 *
4245 * Searches the range @p [__first,__last) for @p count consecutive elements
4246 * equal to @p __val.
4247 */
4248 template<typename _ForwardIterator, typename _Integer, typename _Tp>
4249 inline _ForwardIterator
4250 search_n(_ForwardIterator __first, _ForwardIterator __last,
4251 _Integer __count, const _Tp& __val)
4252 {
4253 // concept requirements
4254 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
4255 __glibcxx_function_requires(_EqualOpConcept<
4256 typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
4257 __glibcxx_requires_valid_range(__first, __last);
4258
4259 return std::__search_n(__first, __last, __count,
4260 __gnu_cxx::__ops::__iter_equals_val(__val));
4261 }
4262
4263
4264 /**
4265 * @brief Search a sequence for a number of consecutive values using a
4266 * predicate.
4267 * @ingroup non_mutating_algorithms
4268 * @param __first A forward iterator.
4269 * @param __last A forward iterator.
4270 * @param __count The number of consecutive values.
4271 * @param __val The value to find.
4272 * @param __binary_pred A binary predicate.
4273 * @return The first iterator @c i in the range @p
4274 * [__first,__last-__count) such that @p
4275 * __binary_pred(*(i+N),__val) is true for each @c N in the range
4276 * @p [0,__count), or @p __last if no such iterator exists.
4277 *
4278 * Searches the range @p [__first,__last) for @p __count
4279 * consecutive elements for which the predicate returns true.
4280 */
4281 template<typename _ForwardIterator, typename _Integer, typename _Tp,
4282 typename _BinaryPredicate>
4283 inline _ForwardIterator
4284 search_n(_ForwardIterator __first, _ForwardIterator __last,
4285 _Integer __count, const _Tp& __val,
4286 _BinaryPredicate __binary_pred)
4287 {
4288 // concept requirements
4289 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
4290 __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
4291 typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
4292 __glibcxx_requires_valid_range(__first, __last);
4293
4294 return std::__search_n(__first, __last, __count,
4295 __gnu_cxx::__ops::__iter_comp_val(__binary_pred, __val));
4296 }
4297
4298#if __cplusplus > 201402L
4299 /** @brief Search a sequence using a Searcher object.
4300 *
4301 * @param __first A forward iterator.
4302 * @param __last A forward iterator.
4303 * @param __searcher A callable object.
4304 * @return @p __searcher(__first,__last).first
4305 */
4306 template<typename _ForwardIterator, typename _Searcher>
4307 inline _ForwardIterator
4308 search(_ForwardIterator __first, _ForwardIterator __last,
4309 const _Searcher& __searcher)
4310 { return __searcher(__first, __last).first; }
4311#endif
4312
4313 /**
4314 * @brief Perform an operation on a sequence.
4315 * @ingroup mutating_algorithms
4316 * @param __first An input iterator.
4317 * @param __last An input iterator.
4318 * @param __result An output iterator.
4319 * @param __unary_op A unary operator.
4320 * @return An output iterator equal to @p __result+(__last-__first).
4321 *
4322 * Applies the operator to each element in the input range and assigns
4323 * the results to successive elements of the output sequence.
4324 * Evaluates @p *(__result+N)=unary_op(*(__first+N)) for each @c N in the
4325 * range @p [0,__last-__first).
4326 *
4327 * @p unary_op must not alter its argument.
4328 */
4329 template<typename _InputIterator, typename _OutputIterator,
4330 typename _UnaryOperation>
4331 _OutputIterator
4332 transform(_InputIterator __first, _InputIterator __last,
4333 _OutputIterator __result, _UnaryOperation __unary_op)
4334 {
4335 // concept requirements
4336 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
4337 __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
4338 // "the type returned by a _UnaryOperation"
4339 __typeof__(__unary_op(*__first))>)
4340 __glibcxx_requires_valid_range(__first, __last);
4341
4342 for (; __first != __last; ++__first, (void)++__result)
4343 *__result = __unary_op(*__first);
4344 return __result;
4345 }
4346
4347 /**
4348 * @brief Perform an operation on corresponding elements of two sequences.
4349 * @ingroup mutating_algorithms
4350 * @param __first1 An input iterator.
4351 * @param __last1 An input iterator.
4352 * @param __first2 An input iterator.
4353 * @param __result An output iterator.
4354 * @param __binary_op A binary operator.
4355 * @return An output iterator equal to @p result+(last-first).
4356 *
4357 * Applies the operator to the corresponding elements in the two
4358 * input ranges and assigns the results to successive elements of the
4359 * output sequence.
4360 * Evaluates @p
4361 * *(__result+N)=__binary_op(*(__first1+N),*(__first2+N)) for each
4362 * @c N in the range @p [0,__last1-__first1).
4363 *
4364 * @p binary_op must not alter either of its arguments.
4365 */
4366 template<typename _InputIterator1, typename _InputIterator2,
4367 typename _OutputIterator, typename _BinaryOperation>
4368 _OutputIterator
4369 transform(_InputIterator1 __first1, _InputIterator1 __last1,
4370 _InputIterator2 __first2, _OutputIterator __result,
4371 _BinaryOperation __binary_op)
4372 {
4373 // concept requirements
4374 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
4375 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
4376 __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
4377 // "the type returned by a _BinaryOperation"
4378 __typeof__(__binary_op(*__first1,*__first2))>)
4379 __glibcxx_requires_valid_range(__first1, __last1);
4380
4381 for (; __first1 != __last1; ++__first1, (void)++__first2, ++__result)
4382 *__result = __binary_op(*__first1, *__first2);
4383 return __result;
4384 }
4385
4386 /**
4387 * @brief Replace each occurrence of one value in a sequence with another
4388 * value.
4389 * @ingroup mutating_algorithms
4390 * @param __first A forward iterator.
4391 * @param __last A forward iterator.
4392 * @param __old_value The value to be replaced.
4393 * @param __new_value The replacement value.
4394 * @return replace() returns no value.
4395 *
4396 * For each iterator @c i in the range @p [__first,__last) if @c *i ==
4397 * @p __old_value then the assignment @c *i = @p __new_value is performed.
4398 */
4399 template<typename _ForwardIterator, typename _Tp>
4400 void
4401 replace(_ForwardIterator __first, _ForwardIterator __last,
4402 const _Tp& __old_value, const _Tp& __new_value)
4403 {
4404 // concept requirements
4405 __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
4406 _ForwardIterator>)
4407 __glibcxx_function_requires(_EqualOpConcept<
4408 typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
4409 __glibcxx_function_requires(_ConvertibleConcept<_Tp,
4410 typename iterator_traits<_ForwardIterator>::value_type>)
4411 __glibcxx_requires_valid_range(__first, __last);
4412
4413 for (; __first != __last; ++__first)
4414 if (*__first == __old_value)
4415 *__first = __new_value;
4416 }
4417
4418 /**
4419 * @brief Replace each value in a sequence for which a predicate returns
4420 * true with another value.
4421 * @ingroup mutating_algorithms
4422 * @param __first A forward iterator.
4423 * @param __last A forward iterator.
4424 * @param __pred A predicate.
4425 * @param __new_value The replacement value.
4426 * @return replace_if() returns no value.
4427 *
4428 * For each iterator @c i in the range @p [__first,__last) if @p __pred(*i)
4429 * is true then the assignment @c *i = @p __new_value is performed.
4430 */
4431 template<typename _ForwardIterator, typename _Predicate, typename _Tp>
4432 void
4433 replace_if(_ForwardIterator __first, _ForwardIterator __last,
4434 _Predicate __pred, const _Tp& __new_value)
4435 {
4436 // concept requirements
4437 __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
4438 _ForwardIterator>)
4439 __glibcxx_function_requires(_ConvertibleConcept<_Tp,
4440 typename iterator_traits<_ForwardIterator>::value_type>)
4441 __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
4442 typename iterator_traits<_ForwardIterator>::value_type>)
4443 __glibcxx_requires_valid_range(__first, __last);
4444
4445 for (; __first != __last; ++__first)
4446 if (__pred(*__first))
4447 *__first = __new_value;
4448 }
4449
4450 /**
4451 * @brief Assign the result of a function object to each value in a
4452 * sequence.
4453 * @ingroup mutating_algorithms
4454 * @param __first A forward iterator.
4455 * @param __last A forward iterator.
4456 * @param __gen A function object taking no arguments and returning
4457 * std::iterator_traits<_ForwardIterator>::value_type
4458 * @return generate() returns no value.
4459 *
4460 * Performs the assignment @c *i = @p __gen() for each @c i in the range
4461 * @p [__first,__last).
4462 */
4463 template<typename _ForwardIterator, typename _Generator>
4464 void
4465 generate(_ForwardIterator __first, _ForwardIterator __last,
4466 _Generator __gen)
4467 {
4468 // concept requirements
4469 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
4470 __glibcxx_function_requires(_GeneratorConcept<_Generator,
4471 typename iterator_traits<_ForwardIterator>::value_type>)
4472 __glibcxx_requires_valid_range(__first, __last);
4473
4474 for (; __first != __last; ++__first)
4475 *__first = __gen();
4476 }
4477
4478 /**
4479 * @brief Assign the result of a function object to each value in a
4480 * sequence.
4481 * @ingroup mutating_algorithms
4482 * @param __first A forward iterator.
4483 * @param __n The length of the sequence.
4484 * @param __gen A function object taking no arguments and returning
4485 * std::iterator_traits<_ForwardIterator>::value_type
4486 * @return The end of the sequence, @p __first+__n
4487 *
4488 * Performs the assignment @c *i = @p __gen() for each @c i in the range
4489 * @p [__first,__first+__n).
4490 *
4491 * _GLIBCXX_RESOLVE_LIB_DEFECTS
4492 * DR 865. More algorithms that throw away information
4493 */
4494 template<typename _OutputIterator, typename _Size, typename _Generator>
4495 _OutputIterator
4496 generate_n(_OutputIterator __first, _Size __n, _Generator __gen)
4497 {
4498 // concept requirements
4499 __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
4500 // "the type returned by a _Generator"
4501 __typeof__(__gen())>)
4502
4503 for (__decltype(__n + 0) __niter = __n;
4504 __niter > 0; --__niter, (void) ++__first)
4505 *__first = __gen();
4506 return __first;
4507 }
4508
4509 /**
4510 * @brief Copy a sequence, removing consecutive duplicate values.
4511 * @ingroup mutating_algorithms
4512 * @param __first An input iterator.
4513 * @param __last An input iterator.
4514 * @param __result An output iterator.
4515 * @return An iterator designating the end of the resulting sequence.
4516 *
4517 * Copies each element in the range @p [__first,__last) to the range
4518 * beginning at @p __result, except that only the first element is copied
4519 * from groups of consecutive elements that compare equal.
4520 * unique_copy() is stable, so the relative order of elements that are
4521 * copied is unchanged.
4522 *
4523 * _GLIBCXX_RESOLVE_LIB_DEFECTS
4524 * DR 241. Does unique_copy() require CopyConstructible and Assignable?
4525 *
4526 * _GLIBCXX_RESOLVE_LIB_DEFECTS
4527 * DR 538. 241 again: Does unique_copy() require CopyConstructible and
4528 * Assignable?
4529 */
4530 template<typename _InputIterator, typename _OutputIterator>
4531 inline _OutputIterator
4532 unique_copy(_InputIterator __first, _InputIterator __last,
4533 _OutputIterator __result)
4534 {
4535 // concept requirements
4536 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
4537 __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
4538 typename iterator_traits<_InputIterator>::value_type>)
4539 __glibcxx_function_requires(_EqualityComparableConcept<
4540 typename iterator_traits<_InputIterator>::value_type>)
4541 __glibcxx_requires_valid_range(__first, __last);
4542
4543 if (__first == __last)
4544 return __result;
4545 return std::__unique_copy(__first, __last, __result,
4546 __gnu_cxx::__ops::__iter_equal_to_iter(),
4547 std::__iterator_category(__first),
4548 std::__iterator_category(__result));
4549 }
4550
4551 /**
4552 * @brief Copy a sequence, removing consecutive values using a predicate.
4553 * @ingroup mutating_algorithms
4554 * @param __first An input iterator.
4555 * @param __last An input iterator.
4556 * @param __result An output iterator.
4557 * @param __binary_pred A binary predicate.
4558 * @return An iterator designating the end of the resulting sequence.
4559 *
4560 * Copies each element in the range @p [__first,__last) to the range
4561 * beginning at @p __result, except that only the first element is copied
4562 * from groups of consecutive elements for which @p __binary_pred returns
4563 * true.
4564 * unique_copy() is stable, so the relative order of elements that are
4565 * copied is unchanged.
4566 *
4567 * _GLIBCXX_RESOLVE_LIB_DEFECTS
4568 * DR 241. Does unique_copy() require CopyConstructible and Assignable?
4569 */
4570 template<typename _InputIterator, typename _OutputIterator,
4571 typename _BinaryPredicate>
4572 inline _OutputIterator
4573 unique_copy(_InputIterator __first, _InputIterator __last,
4574 _OutputIterator __result,
4575 _BinaryPredicate __binary_pred)
4576 {
4577 // concept requirements -- predicates checked later
4578 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
4579 __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
4580 typename iterator_traits<_InputIterator>::value_type>)
4581 __glibcxx_requires_valid_range(__first, __last);
4582
4583 if (__first == __last)
4584 return __result;
4585 return std::__unique_copy(__first, __last, __result,
4586 __gnu_cxx::__ops::__iter_comp_iter(__binary_pred),
4587 std::__iterator_category(__first),
4588 std::__iterator_category(__result));
4589 }
4590
4591#if _GLIBCXX_HOSTED
4592 /**
4593 * @brief Randomly shuffle the elements of a sequence.
4594 * @ingroup mutating_algorithms
4595 * @param __first A forward iterator.
4596 * @param __last A forward iterator.
4597 * @return Nothing.
4598 *
4599 * Reorder the elements in the range @p [__first,__last) using a random
4600 * distribution, so that every possible ordering of the sequence is
4601 * equally likely.
4602 */
4603 template<typename _RandomAccessIterator>
4604 inline void
4605 random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last)
4606 {
4607 // concept requirements
4608 __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
4609 _RandomAccessIterator>)
4610 __glibcxx_requires_valid_range(__first, __last);
4611
4612 if (__first != __last)
4613 for (_RandomAccessIterator __i = __first + 1; __i != __last; ++__i)
4614 {
4615 // XXX rand() % N is not uniformly distributed
4616 _RandomAccessIterator __j = __first
4617 + std::rand() % ((__i - __first) + 1);
4618 if (__i != __j)
4619 std::iter_swap(__i, __j);
4620 }
4621 }
4622#endif
4623
4624 /**
4625 * @brief Shuffle the elements of a sequence using a random number
4626 * generator.
4627 * @ingroup mutating_algorithms
4628 * @param __first A forward iterator.
4629 * @param __last A forward iterator.
4630 * @param __rand The RNG functor or function.
4631 * @return Nothing.
4632 *
4633 * Reorders the elements in the range @p [__first,__last) using @p __rand to
4634 * provide a random distribution. Calling @p __rand(N) for a positive
4635 * integer @p N should return a randomly chosen integer from the
4636 * range [0,N).
4637 */
4638 template<typename _RandomAccessIterator, typename _RandomNumberGenerator>
4639 void
4640 random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last,
4641#if __cplusplus >= 201103L
4642 _RandomNumberGenerator&& __rand)
4643#else
4644 _RandomNumberGenerator& __rand)
4645#endif
4646 {
4647 // concept requirements
4648 __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
4649 _RandomAccessIterator>)
4650 __glibcxx_requires_valid_range(__first, __last);
4651
4652 if (__first == __last)
4653 return;
4654 for (_RandomAccessIterator __i = __first + 1; __i != __last; ++__i)
4655 {
4656 _RandomAccessIterator __j = __first + __rand((__i - __first) + 1);
4657 if (__i != __j)
4658 std::iter_swap(__i, __j);
4659 }
4660 }
4661
4662
4663 /**
4664 * @brief Move elements for which a predicate is true to the beginning
4665 * of a sequence.
4666 * @ingroup mutating_algorithms
4667 * @param __first A forward iterator.
4668 * @param __last A forward iterator.
4669 * @param __pred A predicate functor.
4670 * @return An iterator @p middle such that @p __pred(i) is true for each
4671 * iterator @p i in the range @p [__first,middle) and false for each @p i
4672 * in the range @p [middle,__last).
4673 *
4674 * @p __pred must not modify its operand. @p partition() does not preserve
4675 * the relative ordering of elements in each group, use
4676 * @p stable_partition() if this is needed.
4677 */
4678 template<typename _ForwardIterator, typename _Predicate>
4679 inline _ForwardIterator
4680 partition(_ForwardIterator __first, _ForwardIterator __last,
4681 _Predicate __pred)
4682 {
4683 // concept requirements
4684 __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
4685 _ForwardIterator>)
4686 __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
4687 typename iterator_traits<_ForwardIterator>::value_type>)
4688 __glibcxx_requires_valid_range(__first, __last);
4689
4690 return std::__partition(__first, __last, __pred,
4691 std::__iterator_category(__first));
4692 }
4693
4694
4695 /**
4696 * @brief Sort the smallest elements of a sequence.
4697 * @ingroup sorting_algorithms
4698 * @param __first An iterator.
4699 * @param __middle Another iterator.
4700 * @param __last Another iterator.
4701 * @return Nothing.
4702 *
4703 * Sorts the smallest @p (__middle-__first) elements in the range
4704 * @p [first,last) and moves them to the range @p [__first,__middle). The
4705 * order of the remaining elements in the range @p [__middle,__last) is
4706 * undefined.
4707 * After the sort if @e i and @e j are iterators in the range
4708 * @p [__first,__middle) such that i precedes j and @e k is an iterator in
4709 * the range @p [__middle,__last) then *j<*i and *k<*i are both false.
4710 */
4711 template<typename _RandomAccessIterator>
4712 inline void
4713 partial_sort(_RandomAccessIterator __first,
4714 _RandomAccessIterator __middle,
4715 _RandomAccessIterator __last)
4716 {
4717 // concept requirements
4718 __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
4719 _RandomAccessIterator>)
4720 __glibcxx_function_requires(_LessThanComparableConcept<
4721 typename iterator_traits<_RandomAccessIterator>::value_type>)
4722 __glibcxx_requires_valid_range(__first, __middle);
4723 __glibcxx_requires_valid_range(__middle, __last);
4724 __glibcxx_requires_irreflexive(__first, __last);
4725
4726 std::__partial_sort(__first, __middle, __last,
4727 __gnu_cxx::__ops::__iter_less_iter());
4728 }
4729
4730 /**
4731 * @brief Sort the smallest elements of a sequence using a predicate
4732 * for comparison.
4733 * @ingroup sorting_algorithms
4734 * @param __first An iterator.
4735 * @param __middle Another iterator.
4736 * @param __last Another iterator.
4737 * @param __comp A comparison functor.
4738 * @return Nothing.
4739 *
4740 * Sorts the smallest @p (__middle-__first) elements in the range
4741 * @p [__first,__last) and moves them to the range @p [__first,__middle). The
4742 * order of the remaining elements in the range @p [__middle,__last) is
4743 * undefined.
4744 * After the sort if @e i and @e j are iterators in the range
4745 * @p [__first,__middle) such that i precedes j and @e k is an iterator in
4746 * the range @p [__middle,__last) then @p *__comp(j,*i) and @p __comp(*k,*i)
4747 * are both false.
4748 */
4749 template<typename _RandomAccessIterator, typename _Compare>
4750 inline void
4751 partial_sort(_RandomAccessIterator __first,
4752 _RandomAccessIterator __middle,
4753 _RandomAccessIterator __last,
4754 _Compare __comp)
4755 {
4756 // concept requirements
4757 __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
4758 _RandomAccessIterator>)
4759 __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
4760 typename iterator_traits<_RandomAccessIterator>::value_type,
4761 typename iterator_traits<_RandomAccessIterator>::value_type>)
4762 __glibcxx_requires_valid_range(__first, __middle);
4763 __glibcxx_requires_valid_range(__middle, __last);
4764 __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
4765
4766 std::__partial_sort(__first, __middle, __last,
4767 __gnu_cxx::__ops::__iter_comp_iter(__comp));
4768 }
4769
4770 /**
4771 * @brief Sort a sequence just enough to find a particular position.
4772 * @ingroup sorting_algorithms
4773 * @param __first An iterator.
4774 * @param __nth Another iterator.
4775 * @param __last Another iterator.
4776 * @return Nothing.
4777 *
4778 * Rearranges the elements in the range @p [__first,__last) so that @p *__nth
4779 * is the same element that would have been in that position had the
4780 * whole sequence been sorted. The elements either side of @p *__nth are
4781 * not completely sorted, but for any iterator @e i in the range
4782 * @p [__first,__nth) and any iterator @e j in the range @p [__nth,__last) it
4783 * holds that *j < *i is false.
4784 */
4785 template<typename _RandomAccessIterator>
4786 inline void
4787 nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth,
4788 _RandomAccessIterator __last)
4789 {
4790 // concept requirements
4791 __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
4792 _RandomAccessIterator>)
4793 __glibcxx_function_requires(_LessThanComparableConcept<
4794 typename iterator_traits<_RandomAccessIterator>::value_type>)
4795 __glibcxx_requires_valid_range(__first, __nth);
4796 __glibcxx_requires_valid_range(__nth, __last);
4797 __glibcxx_requires_irreflexive(__first, __last);
4798
4799 if (__first == __last || __nth == __last)
4800 return;
4801
4802 std::__introselect(__first, __nth, __last,
4803 std::__lg(__last - __first) * 2,
4804 __gnu_cxx::__ops::__iter_less_iter());
4805 }
4806
4807 /**
4808 * @brief Sort a sequence just enough to find a particular position
4809 * using a predicate for comparison.
4810 * @ingroup sorting_algorithms
4811 * @param __first An iterator.
4812 * @param __nth Another iterator.
4813 * @param __last Another iterator.
4814 * @param __comp A comparison functor.
4815 * @return Nothing.
4816 *
4817 * Rearranges the elements in the range @p [__first,__last) so that @p *__nth
4818 * is the same element that would have been in that position had the
4819 * whole sequence been sorted. The elements either side of @p *__nth are
4820 * not completely sorted, but for any iterator @e i in the range
4821 * @p [__first,__nth) and any iterator @e j in the range @p [__nth,__last) it
4822 * holds that @p __comp(*j,*i) is false.
4823 */
4824 template<typename _RandomAccessIterator, typename _Compare>
4825 inline void
4826 nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth,
4827 _RandomAccessIterator __last, _Compare __comp)
4828 {
4829 // concept requirements
4830 __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
4831 _RandomAccessIterator>)
4832 __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
4833 typename iterator_traits<_RandomAccessIterator>::value_type,
4834 typename iterator_traits<_RandomAccessIterator>::value_type>)
4835 __glibcxx_requires_valid_range(__first, __nth);
4836 __glibcxx_requires_valid_range(__nth, __last);
4837 __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
4838
4839 if (__first == __last || __nth == __last)
4840 return;
4841
4842 std::__introselect(__first, __nth, __last,
4843 std::__lg(__last - __first) * 2,
4844 __gnu_cxx::__ops::__iter_comp_iter(__comp));
4845 }
4846
4847 /**
4848 * @brief Sort the elements of a sequence.
4849 * @ingroup sorting_algorithms
4850 * @param __first An iterator.
4851 * @param __last Another iterator.
4852 * @return Nothing.
4853 *
4854 * Sorts the elements in the range @p [__first,__last) in ascending order,
4855 * such that for each iterator @e i in the range @p [__first,__last-1),
4856 * *(i+1)<*i is false.
4857 *
4858 * The relative ordering of equivalent elements is not preserved, use
4859 * @p stable_sort() if this is needed.
4860 */
4861 template<typename _RandomAccessIterator>
4862 inline void
4863 sort(_RandomAccessIterator __first, _RandomAccessIterator __last)
4864 {
4865 // concept requirements
4866 __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
4867 _RandomAccessIterator>)
4868 __glibcxx_function_requires(_LessThanComparableConcept<
4869 typename iterator_traits<_RandomAccessIterator>::value_type>)
4870 __glibcxx_requires_valid_range(__first, __last);
4871 __glibcxx_requires_irreflexive(__first, __last);
4872
4873 std::__sort(__first, __last, __gnu_cxx::__ops::__iter_less_iter());
4874 }
4875
4876 /**
4877 * @brief Sort the elements of a sequence using a predicate for comparison.
4878 * @ingroup sorting_algorithms
4879 * @param __first An iterator.
4880 * @param __last Another iterator.
4881 * @param __comp A comparison functor.
4882 * @return Nothing.
4883 *
4884 * Sorts the elements in the range @p [__first,__last) in ascending order,
4885 * such that @p __comp(*(i+1),*i) is false for every iterator @e i in the
4886 * range @p [__first,__last-1).
4887 *
4888 * The relative ordering of equivalent elements is not preserved, use
4889 * @p stable_sort() if this is needed.
4890 */
4891 template<typename _RandomAccessIterator, typename _Compare>
4892 inline void
4893 sort(_RandomAccessIterator __first, _RandomAccessIterator __last,
4894 _Compare __comp)
4895 {
4896 // concept requirements
4897 __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
4898 _RandomAccessIterator>)
4899 __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
4900 typename iterator_traits<_RandomAccessIterator>::value_type,
4901 typename iterator_traits<_RandomAccessIterator>::value_type>)
4902 __glibcxx_requires_valid_range(__first, __last);
4903 __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
4904
4905 std::__sort(__first, __last, __gnu_cxx::__ops::__iter_comp_iter(__comp));
4906 }
4907
4908 template<typename _InputIterator1, typename _InputIterator2,
4909 typename _OutputIterator, typename _Compare>
4910 _OutputIterator
4911 __merge(_InputIterator1 __first1, _InputIterator1 __last1,
4912 _InputIterator2 __first2, _InputIterator2 __last2,
4913 _OutputIterator __result, _Compare __comp)
4914 {
4915 while (__first1 != __last1 && __first2 != __last2)
4916 {
4917 if (__comp(__first2, __first1))
4918 {
4919 *__result = *__first2;
4920 ++__first2;
4921 }
4922 else
4923 {
4924 *__result = *__first1;
4925 ++__first1;
4926 }
4927 ++__result;
4928 }
4929 return std::copy(__first2, __last2,
4930 std::copy(__first1, __last1, __result));
4931 }
4932
4933 /**
4934 * @brief Merges two sorted ranges.
4935 * @ingroup sorting_algorithms
4936 * @param __first1 An iterator.
4937 * @param __first2 Another iterator.
4938 * @param __last1 Another iterator.
4939 * @param __last2 Another iterator.
4940 * @param __result An iterator pointing to the end of the merged range.
4941 * @return An iterator pointing to the first element <em>not less
4942 * than</em> @e val.
4943 *
4944 * Merges the ranges @p [__first1,__last1) and @p [__first2,__last2) into
4945 * the sorted range @p [__result, __result + (__last1-__first1) +
4946 * (__last2-__first2)). Both input ranges must be sorted, and the
4947 * output range must not overlap with either of the input ranges.
4948 * The sort is @e stable, that is, for equivalent elements in the
4949 * two ranges, elements from the first range will always come
4950 * before elements from the second.
4951 */
4952 template<typename _InputIterator1, typename _InputIterator2,
4953 typename _OutputIterator>
4954 inline _OutputIterator
4955 merge(_InputIterator1 __first1, _InputIterator1 __last1,
4956 _InputIterator2 __first2, _InputIterator2 __last2,
4957 _OutputIterator __result)
4958 {
4959 // concept requirements
4960 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
4961 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
4962 __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
4963 typename iterator_traits<_InputIterator1>::value_type>)
4964 __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
4965 typename iterator_traits<_InputIterator2>::value_type>)
4966 __glibcxx_function_requires(_LessThanOpConcept<
4967 typename iterator_traits<_InputIterator2>::value_type,
4968 typename iterator_traits<_InputIterator1>::value_type>)
4969 __glibcxx_requires_sorted_set(__first1, __last1, __first2);
4970 __glibcxx_requires_sorted_set(__first2, __last2, __first1);
4971 __glibcxx_requires_irreflexive2(__first1, __last1);
4972 __glibcxx_requires_irreflexive2(__first2, __last2);
4973
4974 return _GLIBCXX_STD_A::__merge(__first1, __last1,
4975 __first2, __last2, __result,
4976 __gnu_cxx::__ops::__iter_less_iter());
4977 }
4978
4979 /**
4980 * @brief Merges two sorted ranges.
4981 * @ingroup sorting_algorithms
4982 * @param __first1 An iterator.
4983 * @param __first2 Another iterator.
4984 * @param __last1 Another iterator.
4985 * @param __last2 Another iterator.
4986 * @param __result An iterator pointing to the end of the merged range.
4987 * @param __comp A functor to use for comparisons.
4988 * @return An iterator pointing to the first element "not less
4989 * than" @e val.
4990 *
4991 * Merges the ranges @p [__first1,__last1) and @p [__first2,__last2) into
4992 * the sorted range @p [__result, __result + (__last1-__first1) +
4993 * (__last2-__first2)). Both input ranges must be sorted, and the
4994 * output range must not overlap with either of the input ranges.
4995 * The sort is @e stable, that is, for equivalent elements in the
4996 * two ranges, elements from the first range will always come
4997 * before elements from the second.
4998 *
4999 * The comparison function should have the same effects on ordering as
5000 * the function used for the initial sort.
5001 */
5002 template<typename _InputIterator1, typename _InputIterator2,
5003 typename _OutputIterator, typename _Compare>
5004 inline _OutputIterator
5005 merge(_InputIterator1 __first1, _InputIterator1 __last1,
5006 _InputIterator2 __first2, _InputIterator2 __last2,
5007 _OutputIterator __result, _Compare __comp)
5008 {
5009 // concept requirements
5010 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
5011 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
5012 __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
5013 typename iterator_traits<_InputIterator1>::value_type>)
5014 __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
5015 typename iterator_traits<_InputIterator2>::value_type>)
5016 __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
5017 typename iterator_traits<_InputIterator2>::value_type,
5018 typename iterator_traits<_InputIterator1>::value_type>)
5019 __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp);
5020 __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp);
5021 __glibcxx_requires_irreflexive_pred2(__first1, __last1, __comp);
5022 __glibcxx_requires_irreflexive_pred2(__first2, __last2, __comp);
5023
5024 return _GLIBCXX_STD_A::__merge(__first1, __last1,
5025 __first2, __last2, __result,
5026 __gnu_cxx::__ops::__iter_comp_iter(__comp));
5027 }
5028
5029 template<typename _RandomAccessIterator, typename _Compare>
5030 inline void
5031 __stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last,
5032 _Compare __comp)
5033 {
5034 typedef typename iterator_traits<_RandomAccessIterator>::value_type
5035 _ValueType;
5036 typedef typename iterator_traits<_RandomAccessIterator>::difference_type
5037 _DistanceType;
5038
5039 typedef _Temporary_buffer<_RandomAccessIterator, _ValueType> _TmpBuf;
5040 _TmpBuf __buf(__first, std::distance(__first, __last));
5041
5042 if (__buf.begin() == 0)
5043 std::__inplace_stable_sort(__first, __last, __comp);
5044 else
5045 std::__stable_sort_adaptive(__first, __last, __buf.begin(),
5046 _DistanceType(__buf.size()), __comp);
5047 }
5048
5049 /**
5050 * @brief Sort the elements of a sequence, preserving the relative order
5051 * of equivalent elements.
5052 * @ingroup sorting_algorithms
5053 * @param __first An iterator.
5054 * @param __last Another iterator.
5055 * @return Nothing.
5056 *
5057 * Sorts the elements in the range @p [__first,__last) in ascending order,
5058 * such that for each iterator @p i in the range @p [__first,__last-1),
5059 * @p *(i+1)<*i is false.
5060 *
5061 * The relative ordering of equivalent elements is preserved, so any two
5062 * elements @p x and @p y in the range @p [__first,__last) such that
5063 * @p x<y is false and @p y<x is false will have the same relative
5064 * ordering after calling @p stable_sort().
5065 */
5066 template<typename _RandomAccessIterator>
5067 inline void
5068 stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last)
5069 {
5070 // concept requirements
5071 __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
5072 _RandomAccessIterator>)
5073 __glibcxx_function_requires(_LessThanComparableConcept<
5074 typename iterator_traits<_RandomAccessIterator>::value_type>)
5075 __glibcxx_requires_valid_range(__first, __last);
5076 __glibcxx_requires_irreflexive(__first, __last);
5077
5078 _GLIBCXX_STD_A::__stable_sort(__first, __last,
5079 __gnu_cxx::__ops::__iter_less_iter());
5080 }
5081
5082 /**
5083 * @brief Sort the elements of a sequence using a predicate for comparison,
5084 * preserving the relative order of equivalent elements.
5085 * @ingroup sorting_algorithms
5086 * @param __first An iterator.
5087 * @param __last Another iterator.
5088 * @param __comp A comparison functor.
5089 * @return Nothing.
5090 *
5091 * Sorts the elements in the range @p [__first,__last) in ascending order,
5092 * such that for each iterator @p i in the range @p [__first,__last-1),
5093 * @p __comp(*(i+1),*i) is false.
5094 *
5095 * The relative ordering of equivalent elements is preserved, so any two
5096 * elements @p x and @p y in the range @p [__first,__last) such that
5097 * @p __comp(x,y) is false and @p __comp(y,x) is false will have the same
5098 * relative ordering after calling @p stable_sort().
5099 */
5100 template<typename _RandomAccessIterator, typename _Compare>
5101 inline void
5102 stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last,
5103 _Compare __comp)
5104 {
5105 // concept requirements
5106 __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
5107 _RandomAccessIterator>)
5108 __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
5109 typename iterator_traits<_RandomAccessIterator>::value_type,
5110 typename iterator_traits<_RandomAccessIterator>::value_type>)
5111 __glibcxx_requires_valid_range(__first, __last);
5112 __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
5113
5114 _GLIBCXX_STD_A::__stable_sort(__first, __last,
5115 __gnu_cxx::__ops::__iter_comp_iter(__comp));
5116 }
5117
5118 template<typename _InputIterator1, typename _InputIterator2,
5119 typename _OutputIterator,
5120 typename _Compare>
5121 _OutputIterator
5122 __set_union(_InputIterator1 __first1, _InputIterator1 __last1,
5123 _InputIterator2 __first2, _InputIterator2 __last2,
5124 _OutputIterator __result, _Compare __comp)
5125 {
5126 while (__first1 != __last1 && __first2 != __last2)
5127 {
5128 if (__comp(__first1, __first2))
5129 {
5130 *__result = *__first1;
5131 ++__first1;
5132 }
5133 else if (__comp(__first2, __first1))
5134 {
5135 *__result = *__first2;
5136 ++__first2;
5137 }
5138 else
5139 {
5140 *__result = *__first1;
5141 ++__first1;
5142 ++__first2;
5143 }
5144 ++__result;
5145 }
5146 return std::copy(__first2, __last2,
5147 std::copy(__first1, __last1, __result));
5148 }
5149
5150 /**
5151 * @brief Return the union of two sorted ranges.
5152 * @ingroup set_algorithms
5153 * @param __first1 Start of first range.
5154 * @param __last1 End of first range.
5155 * @param __first2 Start of second range.
5156 * @param __last2 End of second range.
5157 * @param __result Start of output range.
5158 * @return End of the output range.
5159 * @ingroup set_algorithms
5160 *
5161 * This operation iterates over both ranges, copying elements present in
5162 * each range in order to the output range. Iterators increment for each
5163 * range. When the current element of one range is less than the other,
5164 * that element is copied and the iterator advanced. If an element is
5165 * contained in both ranges, the element from the first range is copied and
5166 * both ranges advance. The output range may not overlap either input
5167 * range.
5168 */
5169 template<typename _InputIterator1, typename _InputIterator2,
5170 typename _OutputIterator>
5171 inline _OutputIterator
5172 set_union(_InputIterator1 __first1, _InputIterator1 __last1,
5173 _InputIterator2 __first2, _InputIterator2 __last2,
5174 _OutputIterator __result)
5175 {
5176 // concept requirements
5177 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
5178 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
5179 __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
5180 typename iterator_traits<_InputIterator1>::value_type>)
5181 __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
5182 typename iterator_traits<_InputIterator2>::value_type>)
5183 __glibcxx_function_requires(_LessThanOpConcept<
5184 typename iterator_traits<_InputIterator1>::value_type,
5185 typename iterator_traits<_InputIterator2>::value_type>)
5186 __glibcxx_function_requires(_LessThanOpConcept<
5187 typename iterator_traits<_InputIterator2>::value_type,
5188 typename iterator_traits<_InputIterator1>::value_type>)
5189 __glibcxx_requires_sorted_set(__first1, __last1, __first2);
5190 __glibcxx_requires_sorted_set(__first2, __last2, __first1);
5191 __glibcxx_requires_irreflexive2(__first1, __last1);
5192 __glibcxx_requires_irreflexive2(__first2, __last2);
5193
5194 return _GLIBCXX_STD_A::__set_union(__first1, __last1,
5195 __first2, __last2, __result,
5196 __gnu_cxx::__ops::__iter_less_iter());
5197 }
5198
5199 /**
5200 * @brief Return the union of two sorted ranges using a comparison functor.
5201 * @ingroup set_algorithms
5202 * @param __first1 Start of first range.
5203 * @param __last1 End of first range.
5204 * @param __first2 Start of second range.
5205 * @param __last2 End of second range.
5206 * @param __result Start of output range.
5207 * @param __comp The comparison functor.
5208 * @return End of the output range.
5209 * @ingroup set_algorithms
5210 *
5211 * This operation iterates over both ranges, copying elements present in
5212 * each range in order to the output range. Iterators increment for each
5213 * range. When the current element of one range is less than the other
5214 * according to @p __comp, that element is copied and the iterator advanced.
5215 * If an equivalent element according to @p __comp is contained in both
5216 * ranges, the element from the first range is copied and both ranges
5217 * advance. The output range may not overlap either input range.
5218 */
5219 template<typename _InputIterator1, typename _InputIterator2,
5220 typename _OutputIterator, typename _Compare>
5221 inline _OutputIterator
5222 set_union(_InputIterator1 __first1, _InputIterator1 __last1,
5223 _InputIterator2 __first2, _InputIterator2 __last2,
5224 _OutputIterator __result, _Compare __comp)
5225 {
5226 // concept requirements
5227 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
5228 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
5229 __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
5230 typename iterator_traits<_InputIterator1>::value_type>)
5231 __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
5232 typename iterator_traits<_InputIterator2>::value_type>)
5233 __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
5234 typename iterator_traits<_InputIterator1>::value_type,
5235 typename iterator_traits<_InputIterator2>::value_type>)
5236 __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
5237 typename iterator_traits<_InputIterator2>::value_type,
5238 typename iterator_traits<_InputIterator1>::value_type>)
5239 __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp);
5240 __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp);
5241 __glibcxx_requires_irreflexive_pred2(__first1, __last1, __comp);
5242 __glibcxx_requires_irreflexive_pred2(__first2, __last2, __comp);
5243
5244 return _GLIBCXX_STD_A::__set_union(__first1, __last1,
5245 __first2, __last2, __result,
5246 __gnu_cxx::__ops::__iter_comp_iter(__comp));
5247 }
5248
5249 template<typename _InputIterator1, typename _InputIterator2,
5250 typename _OutputIterator,
5251 typename _Compare>
5252 _OutputIterator
5253 __set_intersection(_InputIterator1 __first1, _InputIterator1 __last1,
5254 _InputIterator2 __first2, _InputIterator2 __last2,
5255 _OutputIterator __result, _Compare __comp)
5256 {
5257 while (__first1 != __last1 && __first2 != __last2)
5258 if (__comp(__first1, __first2))
5259 ++__first1;
5260 else if (__comp(__first2, __first1))
5261 ++__first2;
5262 else
5263 {
5264 *__result = *__first1;
5265 ++__first1;
5266 ++__first2;
5267 ++__result;
5268 }
5269 return __result;
5270 }
5271
5272 /**
5273 * @brief Return the intersection of two sorted ranges.
5274 * @ingroup set_algorithms
5275 * @param __first1 Start of first range.
5276 * @param __last1 End of first range.
5277 * @param __first2 Start of second range.
5278 * @param __last2 End of second range.
5279 * @param __result Start of output range.
5280 * @return End of the output range.
5281 * @ingroup set_algorithms
5282 *
5283 * This operation iterates over both ranges, copying elements present in
5284 * both ranges in order to the output range. Iterators increment for each
5285 * range. When the current element of one range is less than the other,
5286 * that iterator advances. If an element is contained in both ranges, the
5287 * element from the first range is copied and both ranges advance. The
5288 * output range may not overlap either input range.
5289 */
5290 template<typename _InputIterator1, typename _InputIterator2,
5291 typename _OutputIterator>
5292 inline _OutputIterator
5293 set_intersection(_InputIterator1 __first1, _InputIterator1 __last1,
5294 _InputIterator2 __first2, _InputIterator2 __last2,
5295 _OutputIterator __result)
5296 {
5297 // concept requirements
5298 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
5299 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
5300 __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
5301 typename iterator_traits<_InputIterator1>::value_type>)
5302 __glibcxx_function_requires(_LessThanOpConcept<
5303 typename iterator_traits<_InputIterator1>::value_type,
5304 typename iterator_traits<_InputIterator2>::value_type>)
5305 __glibcxx_function_requires(_LessThanOpConcept<
5306 typename iterator_traits<_InputIterator2>::value_type,
5307 typename iterator_traits<_InputIterator1>::value_type>)
5308 __glibcxx_requires_sorted_set(__first1, __last1, __first2);
5309 __glibcxx_requires_sorted_set(__first2, __last2, __first1);
5310 __glibcxx_requires_irreflexive2(__first1, __last1);
5311 __glibcxx_requires_irreflexive2(__first2, __last2);
5312
5313 return _GLIBCXX_STD_A::__set_intersection(__first1, __last1,
5314 __first2, __last2, __result,
5315 __gnu_cxx::__ops::__iter_less_iter());
5316 }
5317
5318 /**
5319 * @brief Return the intersection of two sorted ranges using comparison
5320 * functor.
5321 * @ingroup set_algorithms
5322 * @param __first1 Start of first range.
5323 * @param __last1 End of first range.
5324 * @param __first2 Start of second range.
5325 * @param __last2 End of second range.
5326 * @param __result Start of output range.
5327 * @param __comp The comparison functor.
5328 * @return End of the output range.
5329 * @ingroup set_algorithms
5330 *
5331 * This operation iterates over both ranges, copying elements present in
5332 * both ranges in order to the output range. Iterators increment for each
5333 * range. When the current element of one range is less than the other
5334 * according to @p __comp, that iterator advances. If an element is
5335 * contained in both ranges according to @p __comp, the element from the
5336 * first range is copied and both ranges advance. The output range may not
5337 * overlap either input range.
5338 */
5339 template<typename _InputIterator1, typename _InputIterator2,
5340 typename _OutputIterator, typename _Compare>
5341 inline _OutputIterator
5342 set_intersection(_InputIterator1 __first1, _InputIterator1 __last1,
5343 _InputIterator2 __first2, _InputIterator2 __last2,
5344 _OutputIterator __result, _Compare __comp)
5345 {
5346 // concept requirements
5347 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
5348 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
5349 __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
5350 typename iterator_traits<_InputIterator1>::value_type>)
5351 __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
5352 typename iterator_traits<_InputIterator1>::value_type,
5353 typename iterator_traits<_InputIterator2>::value_type>)
5354 __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
5355 typename iterator_traits<_InputIterator2>::value_type,
5356 typename iterator_traits<_InputIterator1>::value_type>)
5357 __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp);
5358 __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp);
5359 __glibcxx_requires_irreflexive_pred2(__first1, __last1, __comp);
5360 __glibcxx_requires_irreflexive_pred2(__first2, __last2, __comp);
5361
5362 return _GLIBCXX_STD_A::__set_intersection(__first1, __last1,
5363 __first2, __last2, __result,
5364 __gnu_cxx::__ops::__iter_comp_iter(__comp));
5365 }
5366
5367 template<typename _InputIterator1, typename _InputIterator2,
5368 typename _OutputIterator,
5369 typename _Compare>
5370 _OutputIterator
5371 __set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5372 _InputIterator2 __first2, _InputIterator2 __last2,
5373 _OutputIterator __result, _Compare __comp)
5374 {
5375 while (__first1 != __last1 && __first2 != __last2)
5376 if (__comp(__first1, __first2))
5377 {
5378 *__result = *__first1;
5379 ++__first1;
5380 ++__result;
5381 }
5382 else if (__comp(__first2, __first1))
5383 ++__first2;
5384 else
5385 {
5386 ++__first1;
5387 ++__first2;
5388 }
5389 return std::copy(__first1, __last1, __result);
5390 }
5391
5392 /**
5393 * @brief Return the difference of two sorted ranges.
5394 * @ingroup set_algorithms
5395 * @param __first1 Start of first range.
5396 * @param __last1 End of first range.
5397 * @param __first2 Start of second range.
5398 * @param __last2 End of second range.
5399 * @param __result Start of output range.
5400 * @return End of the output range.
5401 * @ingroup set_algorithms
5402 *
5403 * This operation iterates over both ranges, copying elements present in
5404 * the first range but not the second in order to the output range.
5405 * Iterators increment for each range. When the current element of the
5406 * first range is less than the second, that element is copied and the
5407 * iterator advances. If the current element of the second range is less,
5408 * the iterator advances, but no element is copied. If an element is
5409 * contained in both ranges, no elements are copied and both ranges
5410 * advance. The output range may not overlap either input range.
5411 */
5412 template<typename _InputIterator1, typename _InputIterator2,
5413 typename _OutputIterator>
5414 inline _OutputIterator
5415 set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5416 _InputIterator2 __first2, _InputIterator2 __last2,
5417 _OutputIterator __result)
5418 {
5419 // concept requirements
5420 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
5421 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
5422 __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
5423 typename iterator_traits<_InputIterator1>::value_type>)
5424 __glibcxx_function_requires(_LessThanOpConcept<
5425 typename iterator_traits<_InputIterator1>::value_type,
5426 typename iterator_traits<_InputIterator2>::value_type>)
5427 __glibcxx_function_requires(_LessThanOpConcept<
5428 typename iterator_traits<_InputIterator2>::value_type,
5429 typename iterator_traits<_InputIterator1>::value_type>)
5430 __glibcxx_requires_sorted_set(__first1, __last1, __first2);
5431 __glibcxx_requires_sorted_set(__first2, __last2, __first1);
5432 __glibcxx_requires_irreflexive2(__first1, __last1);
5433 __glibcxx_requires_irreflexive2(__first2, __last2);
5434
5435 return _GLIBCXX_STD_A::__set_difference(__first1, __last1,
5436 __first2, __last2, __result,
5437 __gnu_cxx::__ops::__iter_less_iter());
5438 }
5439
5440 /**
5441 * @brief Return the difference of two sorted ranges using comparison
5442 * functor.
5443 * @ingroup set_algorithms
5444 * @param __first1 Start of first range.
5445 * @param __last1 End of first range.
5446 * @param __first2 Start of second range.
5447 * @param __last2 End of second range.
5448 * @param __result Start of output range.
5449 * @param __comp The comparison functor.
5450 * @return End of the output range.
5451 * @ingroup set_algorithms
5452 *
5453 * This operation iterates over both ranges, copying elements present in
5454 * the first range but not the second in order to the output range.
5455 * Iterators increment for each range. When the current element of the
5456 * first range is less than the second according to @p __comp, that element
5457 * is copied and the iterator advances. If the current element of the
5458 * second range is less, no element is copied and the iterator advances.
5459 * If an element is contained in both ranges according to @p __comp, no
5460 * elements are copied and both ranges advance. The output range may not
5461 * overlap either input range.
5462 */
5463 template<typename _InputIterator1, typename _InputIterator2,
5464 typename _OutputIterator, typename _Compare>
5465 inline _OutputIterator
5466 set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5467 _InputIterator2 __first2, _InputIterator2 __last2,
5468 _OutputIterator __result, _Compare __comp)
5469 {
5470 // concept requirements
5471 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
5472 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
5473 __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
5474 typename iterator_traits<_InputIterator1>::value_type>)
5475 __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
5476 typename iterator_traits<_InputIterator1>::value_type,
5477 typename iterator_traits<_InputIterator2>::value_type>)
5478 __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
5479 typename iterator_traits<_InputIterator2>::value_type,
5480 typename iterator_traits<_InputIterator1>::value_type>)
5481 __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp);
5482 __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp);
5483 __glibcxx_requires_irreflexive_pred2(__first1, __last1, __comp);
5484 __glibcxx_requires_irreflexive_pred2(__first2, __last2, __comp);
5485
5486 return _GLIBCXX_STD_A::__set_difference(__first1, __last1,
5487 __first2, __last2, __result,
5488 __gnu_cxx::__ops::__iter_comp_iter(__comp));
5489 }
5490
5491 template<typename _InputIterator1, typename _InputIterator2,
5492 typename _OutputIterator,
5493 typename _Compare>
5494 _OutputIterator
5495 __set_symmetric_difference(_InputIterator1 __first1,
5496 _InputIterator1 __last1,
5497 _InputIterator2 __first2,
5498 _InputIterator2 __last2,
5499 _OutputIterator __result,
5500 _Compare __comp)
5501 {
5502 while (__first1 != __last1 && __first2 != __last2)
5503 if (__comp(__first1, __first2))
5504 {
5505 *__result = *__first1;
5506 ++__first1;
5507 ++__result;
5508 }
5509 else if (__comp(__first2, __first1))
5510 {
5511 *__result = *__first2;
5512 ++__first2;
5513 ++__result;
5514 }
5515 else
5516 {
5517 ++__first1;
5518 ++__first2;
5519 }
5520 return std::copy(__first2, __last2,
5521 std::copy(__first1, __last1, __result));
5522 }
5523
5524 /**
5525 * @brief Return the symmetric difference of two sorted ranges.
5526 * @ingroup set_algorithms
5527 * @param __first1 Start of first range.
5528 * @param __last1 End of first range.
5529 * @param __first2 Start of second range.
5530 * @param __last2 End of second range.
5531 * @param __result Start of output range.
5532 * @return End of the output range.
5533 * @ingroup set_algorithms
5534 *
5535 * This operation iterates over both ranges, copying elements present in
5536 * one range but not the other in order to the output range. Iterators
5537 * increment for each range. When the current element of one range is less
5538 * than the other, that element is copied and the iterator advances. If an
5539 * element is contained in both ranges, no elements are copied and both
5540 * ranges advance. The output range may not overlap either input range.
5541 */
5542 template<typename _InputIterator1, typename _InputIterator2,
5543 typename _OutputIterator>
5544 inline _OutputIterator
5545 set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5546 _InputIterator2 __first2, _InputIterator2 __last2,
5547 _OutputIterator __result)
5548 {
5549 // concept requirements
5550 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
5551 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
5552 __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
5553 typename iterator_traits<_InputIterator1>::value_type>)
5554 __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
5555 typename iterator_traits<_InputIterator2>::value_type>)
5556 __glibcxx_function_requires(_LessThanOpConcept<
5557 typename iterator_traits<_InputIterator1>::value_type,
5558 typename iterator_traits<_InputIterator2>::value_type>)
5559 __glibcxx_function_requires(_LessThanOpConcept<
5560 typename iterator_traits<_InputIterator2>::value_type,
5561 typename iterator_traits<_InputIterator1>::value_type>)
5562 __glibcxx_requires_sorted_set(__first1, __last1, __first2);
5563 __glibcxx_requires_sorted_set(__first2, __last2, __first1);
5564 __glibcxx_requires_irreflexive2(__first1, __last1);
5565 __glibcxx_requires_irreflexive2(__first2, __last2);
5566
5567 return _GLIBCXX_STD_A::__set_symmetric_difference(__first1, __last1,
5568 __first2, __last2, __result,
5569 __gnu_cxx::__ops::__iter_less_iter());
5570 }
5571
5572 /**
5573 * @brief Return the symmetric difference of two sorted ranges using
5574 * comparison functor.
5575 * @ingroup set_algorithms
5576 * @param __first1 Start of first range.
5577 * @param __last1 End of first range.
5578 * @param __first2 Start of second range.
5579 * @param __last2 End of second range.
5580 * @param __result Start of output range.
5581 * @param __comp The comparison functor.
5582 * @return End of the output range.
5583 * @ingroup set_algorithms
5584 *
5585 * This operation iterates over both ranges, copying elements present in
5586 * one range but not the other in order to the output range. Iterators
5587 * increment for each range. When the current element of one range is less
5588 * than the other according to @p comp, that element is copied and the
5589 * iterator advances. If an element is contained in both ranges according
5590 * to @p __comp, no elements are copied and both ranges advance. The output
5591 * range may not overlap either input range.
5592 */
5593 template<typename _InputIterator1, typename _InputIterator2,
5594 typename _OutputIterator, typename _Compare>
5595 inline _OutputIterator
5596 set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5597 _InputIterator2 __first2, _InputIterator2 __last2,
5598 _OutputIterator __result,
5599 _Compare __comp)
5600 {
5601 // concept requirements
5602 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
5603 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
5604 __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
5605 typename iterator_traits<_InputIterator1>::value_type>)
5606 __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
5607 typename iterator_traits<_InputIterator2>::value_type>)
5608 __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
5609 typename iterator_traits<_InputIterator1>::value_type,
5610 typename iterator_traits<_InputIterator2>::value_type>)
5611 __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
5612 typename iterator_traits<_InputIterator2>::value_type,
5613 typename iterator_traits<_InputIterator1>::value_type>)
5614 __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp);
5615 __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp);
5616 __glibcxx_requires_irreflexive_pred2(__first1, __last1, __comp);
5617 __glibcxx_requires_irreflexive_pred2(__first2, __last2, __comp);
5618
5619 return _GLIBCXX_STD_A::__set_symmetric_difference(__first1, __last1,
5620 __first2, __last2, __result,
5621 __gnu_cxx::__ops::__iter_comp_iter(__comp));
5622 }
5623
5624 template<typename _ForwardIterator, typename _Compare>
5625 _GLIBCXX14_CONSTEXPR
5626 _ForwardIterator
5627 __min_element(_ForwardIterator __first, _ForwardIterator __last,
5628 _Compare __comp)
5629 {
5630 if (__first == __last)
5631 return __first;
5632 _ForwardIterator __result = __first;
5633 while (++__first != __last)
5634 if (__comp(__first, __result))
5635 __result = __first;
5636 return __result;
5637 }
5638
5639 /**
5640 * @brief Return the minimum element in a range.
5641 * @ingroup sorting_algorithms
5642 * @param __first Start of range.
5643 * @param __last End of range.
5644 * @return Iterator referencing the first instance of the smallest value.
5645 */
5646 template<typename _ForwardIterator>
5647 _GLIBCXX14_CONSTEXPR
5648 _ForwardIterator
5649 inline min_element(_ForwardIterator __first, _ForwardIterator __last)
5650 {
5651 // concept requirements
5652 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
5653 __glibcxx_function_requires(_LessThanComparableConcept<
5654 typename iterator_traits<_ForwardIterator>::value_type>)
5655 __glibcxx_requires_valid_range(__first, __last);
5656 __glibcxx_requires_irreflexive(__first, __last);
5657
5658 return _GLIBCXX_STD_A::__min_element(__first, __last,
5659 __gnu_cxx::__ops::__iter_less_iter());
5660 }
5661
5662 /**
5663 * @brief Return the minimum element in a range using comparison functor.
5664 * @ingroup sorting_algorithms
5665 * @param __first Start of range.
5666 * @param __last End of range.
5667 * @param __comp Comparison functor.
5668 * @return Iterator referencing the first instance of the smallest value
5669 * according to __comp.
5670 */
5671 template<typename _ForwardIterator, typename _Compare>
5672 _GLIBCXX14_CONSTEXPR
5673 inline _ForwardIterator
5674 min_element(_ForwardIterator __first, _ForwardIterator __last,
5675 _Compare __comp)
5676 {
5677 // concept requirements
5678 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
5679 __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
5680 typename iterator_traits<_ForwardIterator>::value_type,
5681 typename iterator_traits<_ForwardIterator>::value_type>)
5682 __glibcxx_requires_valid_range(__first, __last);
5683 __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
5684
5685 return _GLIBCXX_STD_A::__min_element(__first, __last,
5686 __gnu_cxx::__ops::__iter_comp_iter(__comp));
5687 }
5688
5689 template<typename _ForwardIterator, typename _Compare>
5690 _GLIBCXX14_CONSTEXPR
5691 _ForwardIterator
5692 __max_element(_ForwardIterator __first, _ForwardIterator __last,
5693 _Compare __comp)
5694 {
5695 if (__first == __last) return __first;
5696 _ForwardIterator __result = __first;
5697 while (++__first != __last)
5698 if (__comp(__result, __first))
5699 __result = __first;
5700 return __result;
5701 }
5702
5703 /**
5704 * @brief Return the maximum element in a range.
5705 * @ingroup sorting_algorithms
5706 * @param __first Start of range.
5707 * @param __last End of range.
5708 * @return Iterator referencing the first instance of the largest value.
5709 */
5710 template<typename _ForwardIterator>
5711 _GLIBCXX14_CONSTEXPR
5712 inline _ForwardIterator
5713 max_element(_ForwardIterator __first, _ForwardIterator __last)
5714 {
5715 // concept requirements
5716 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
5717 __glibcxx_function_requires(_LessThanComparableConcept<
5718 typename iterator_traits<_ForwardIterator>::value_type>)
5719 __glibcxx_requires_valid_range(__first, __last);
5720 __glibcxx_requires_irreflexive(__first, __last);
5721
5722 return _GLIBCXX_STD_A::__max_element(__first, __last,
5723 __gnu_cxx::__ops::__iter_less_iter());
5724 }
5725
5726 /**
5727 * @brief Return the maximum element in a range using comparison functor.
5728 * @ingroup sorting_algorithms
5729 * @param __first Start of range.
5730 * @param __last End of range.
5731 * @param __comp Comparison functor.
5732 * @return Iterator referencing the first instance of the largest value
5733 * according to __comp.
5734 */
5735 template<typename _ForwardIterator, typename _Compare>
5736 _GLIBCXX14_CONSTEXPR
5737 inline _ForwardIterator
5738 max_element(_ForwardIterator __first, _ForwardIterator __last,
5739 _Compare __comp)
5740 {
5741 // concept requirements
5742 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
5743 __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
5744 typename iterator_traits<_ForwardIterator>::value_type,
5745 typename iterator_traits<_ForwardIterator>::value_type>)
5746 __glibcxx_requires_valid_range(__first, __last);
5747 __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
5748
5749 return _GLIBCXX_STD_A::__max_element(__first, __last,
5750 __gnu_cxx::__ops::__iter_comp_iter(__comp));
5751 }
5752
5753#if __cplusplus >= 201402L
5754 /// Reservoir sampling algorithm.
5755 template<typename _InputIterator, typename _RandomAccessIterator,
5756 typename _Size, typename _UniformRandomBitGenerator>
5757 _RandomAccessIterator
5758 __sample(_InputIterator __first, _InputIterator __last, input_iterator_tag,
5759 _RandomAccessIterator __out, random_access_iterator_tag,
5760 _Size __n, _UniformRandomBitGenerator&& __g)
5761 {
5762 using __distrib_type = uniform_int_distribution<_Size>;
5763 using __param_type = typename __distrib_type::param_type;
5764 __distrib_type __d{};
5765 _Size __sample_sz = 0;
5766 while (__first != __last && __sample_sz != __n)
5767 {
5768 __out[__sample_sz++] = *__first;
5769 ++__first;
5770 }
5771 for (auto __pop_sz = __sample_sz; __first != __last;
5772 ++__first, (void) ++__pop_sz)
5773 {
5774 const auto __k = __d(__g, __param_type{0, __pop_sz});
5775 if (__k < __n)
5776 __out[__k] = *__first;
5777 }
5778 return __out + __sample_sz;
5779 }
5780
5781 /// Selection sampling algorithm.
5782 template<typename _ForwardIterator, typename _OutputIterator, typename _Cat,
5783 typename _Size, typename _UniformRandomBitGenerator>
5784 _OutputIterator
5785 __sample(_ForwardIterator __first, _ForwardIterator __last,
5786 forward_iterator_tag,
5787 _OutputIterator __out, _Cat,
5788 _Size __n, _UniformRandomBitGenerator&& __g)
5789 {
5790 using __distrib_type = uniform_int_distribution<_Size>;
5791 using __param_type = typename __distrib_type::param_type;
5792 using _USize = make_unsigned_t<_Size>;
5793 using _Gen = remove_reference_t<_UniformRandomBitGenerator>;
5794 using __uc_type = common_type_t<typename _Gen::result_type, _USize>;
5795
5796 if (__first == __last)
5797 return __out;
5798
5799 __distrib_type __d{};
5800 _Size __unsampled_sz = std::distance(__first, __last);
5801 __n = std::min(__n, __unsampled_sz);
5802
5803 // If possible, we use __gen_two_uniform_ints to efficiently produce
5804 // two random numbers using a single distribution invocation:
5805
5806 const __uc_type __urngrange = __g.max() - __g.min();
5807 if (__urngrange / __uc_type(__unsampled_sz) >= __uc_type(__unsampled_sz))
5808 // I.e. (__urngrange >= __unsampled_sz * __unsampled_sz) but without
5809 // wrapping issues.
5810 {
5811 while (__n != 0 && __unsampled_sz >= 2)
5812 {
5813 const pair<_Size, _Size> __p =
5814 __gen_two_uniform_ints(__unsampled_sz, __unsampled_sz - 1, __g);
5815
5816 --__unsampled_sz;
5817 if (__p.first < __n)
5818 {
5819 *__out++ = *__first;
5820 --__n;
5821 }
5822
5823 ++__first;
5824
5825 if (__n == 0) break;
5826
5827 --__unsampled_sz;
5828 if (__p.second < __n)
5829 {
5830 *__out++ = *__first;
5831 --__n;
5832 }
5833
5834 ++__first;
5835 }
5836 }
5837
5838 // The loop above is otherwise equivalent to this one-at-a-time version:
5839
5840 for (; __n != 0; ++__first)
5841 if (__d(__g, __param_type{0, --__unsampled_sz}) < __n)
5842 {
5843 *__out++ = *__first;
5844 --__n;
5845 }
5846 return __out;
5847 }
5848
5849#if __cplusplus > 201402L
5850#define __cpp_lib_sample 201603
5851 /// Take a random sample from a population.
5852 template<typename _PopulationIterator, typename _SampleIterator,
5853 typename _Distance, typename _UniformRandomBitGenerator>
5854 _SampleIterator
5855 sample(_PopulationIterator __first, _PopulationIterator __last,
5856 _SampleIterator __out, _Distance __n,
5857 _UniformRandomBitGenerator&& __g)
5858 {
5859 using __pop_cat = typename
5860 std::iterator_traits<_PopulationIterator>::iterator_category;
5861 using __samp_cat = typename
5862 std::iterator_traits<_SampleIterator>::iterator_category;
5863
5864 static_assert(
5865 __or_<is_convertible<__pop_cat, forward_iterator_tag>,
5866 is_convertible<__samp_cat, random_access_iterator_tag>>::value,
5867 "output range must use a RandomAccessIterator when input range"
5868 " does not meet the ForwardIterator requirements");
5869
5870 static_assert(is_integral<_Distance>::value,
5871 "sample size must be an integer type");
5872
5873 typename iterator_traits<_PopulationIterator>::difference_type __d = __n;
5874 return _GLIBCXX_STD_A::
5875 __sample(__first, __last, __pop_cat{}, __out, __samp_cat{}, __d,
5876 std::forward<_UniformRandomBitGenerator>(__g));
5877 }
5878#endif // C++17
5879#endif // C++14
5880
5881_GLIBCXX_END_NAMESPACE_ALGO
5882_GLIBCXX_END_NAMESPACE_VERSION
5883} // namespace std
5884
5885#endif /* _STL_ALGO_H */
5886