re PR libstdc++/20577 (iter_swap doesn't work anymore with vector<bool>)
[gcc.git] / libstdc++-v3 / include / bits / stl_algobase.h
1 // Bits and pieces used in algorithms -*- C++ -*-
2
3 // Copyright (C) 2001, 2002, 2003, 2004, 2005 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 2, 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 // You should have received a copy of the GNU General Public License along
17 // with this library; see the file COPYING. If not, write to the Free
18 // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
19 // USA.
20
21 // As a special exception, you may use this file as part of a free software
22 // library without restriction. Specifically, if other files instantiate
23 // templates or use macros or inline functions from this file, or you compile
24 // this file and link it with other files to produce an executable, this
25 // file does not by itself cause the resulting executable to be covered by
26 // the GNU General Public License. This exception does not however
27 // invalidate any other reasons why the executable file might be covered by
28 // the GNU General Public License.
29
30 /*
31 *
32 * Copyright (c) 1994
33 * Hewlett-Packard Company
34 *
35 * Permission to use, copy, modify, distribute and sell this software
36 * and its documentation for any purpose is hereby granted without fee,
37 * provided that the above copyright notice appear in all copies and
38 * that both that copyright notice and this permission notice appear
39 * in supporting documentation. Hewlett-Packard Company makes no
40 * representations about the suitability of this software for any
41 * purpose. It is provided "as is" without express or implied warranty.
42 *
43 *
44 * Copyright (c) 1996-1998
45 * Silicon Graphics Computer Systems, Inc.
46 *
47 * Permission to use, copy, modify, distribute and sell this software
48 * and its documentation for any purpose is hereby granted without fee,
49 * provided that the above copyright notice appear in all copies and
50 * that both that copyright notice and this permission notice appear
51 * in supporting documentation. Silicon Graphics makes no
52 * representations about the suitability of this software for any
53 * purpose. It is provided "as is" without express or implied warranty.
54 */
55
56 /** @file stl_algobase.h
57 * This is an internal header file, included by other library headers.
58 * You should not attempt to use it directly.
59 */
60
61 #ifndef _ALGOBASE_H
62 #define _ALGOBASE_H 1
63
64 #include <bits/c++config.h>
65 #include <cstring>
66 #include <climits>
67 #include <cstdlib>
68 #include <cstddef>
69 #include <iosfwd>
70 #include <bits/stl_pair.h>
71 #include <bits/cpp_type_traits.h>
72 #include <bits/stl_iterator_base_types.h>
73 #include <bits/stl_iterator_base_funcs.h>
74 #include <bits/stl_iterator.h>
75 #include <bits/concept_check.h>
76 #include <debug/debug.h>
77
78 namespace std
79 {
80
81 /**
82 * @brief Swaps two values.
83 * @param a A thing of arbitrary type.
84 * @param b Another thing of arbitrary type.
85 * @return Nothing.
86 *
87 * This is the simple classic generic implementation. It will work on
88 * any type which has a copy constructor and an assignment operator.
89 */
90 template<typename _Tp>
91 inline void
92 swap(_Tp& __a, _Tp& __b)
93 {
94 // concept requirements
95 __glibcxx_function_requires(_SGIAssignableConcept<_Tp>)
96
97 const _Tp __tmp = __a;
98 __a = __b;
99 __b = __tmp;
100 }
101
102 // See http://gcc.gnu.org/ml/libstdc++/2004-08/msg00167.html: in a
103 // nutshell, we are partially implementing the resolution of DR 187,
104 // when it's safe, i.e., the value_types are equal.
105 template<bool _BoolType>
106 struct __iter_swap
107 {
108 template<typename _ForwardIterator1, typename _ForwardIterator2>
109 static void
110 iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
111 {
112 typedef typename iterator_traits<_ForwardIterator1>::value_type
113 _ValueType1;
114 const _ValueType1 __tmp = *__a;
115 *__a = *__b;
116 *__b = __tmp;
117 }
118 };
119
120 template<>
121 struct __iter_swap<true>
122 {
123 template<typename _ForwardIterator1, typename _ForwardIterator2>
124 static void
125 iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
126 {
127 swap(*__a, *__b);
128 }
129 };
130
131 /**
132 * @brief Swaps the contents of two iterators.
133 * @param a An iterator.
134 * @param b Another iterator.
135 * @return Nothing.
136 *
137 * This function swaps the values pointed to by two iterators, not the
138 * iterators themselves.
139 */
140 template<typename _ForwardIterator1, typename _ForwardIterator2>
141 inline void
142 iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
143 {
144 typedef typename iterator_traits<_ForwardIterator1>::value_type
145 _ValueType1;
146 typedef typename iterator_traits<_ForwardIterator2>::value_type
147 _ValueType2;
148
149 // concept requirements
150 __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
151 _ForwardIterator1>)
152 __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
153 _ForwardIterator2>)
154 __glibcxx_function_requires(_ConvertibleConcept<_ValueType1,
155 _ValueType2>)
156 __glibcxx_function_requires(_ConvertibleConcept<_ValueType2,
157 _ValueType1>)
158
159 typedef typename iterator_traits<_ForwardIterator1>::reference
160 _ReferenceType1;
161 typedef typename iterator_traits<_ForwardIterator2>::reference
162 _ReferenceType2;
163 std::__iter_swap<__are_same<_ValueType1, _ValueType2>::__value &&
164 __are_same<_ValueType1 &, _ReferenceType1>::__value &&
165 __are_same<_ValueType2 &, _ReferenceType2>::__value>::
166 iter_swap(__a, __b);
167 }
168
169 #undef min
170 #undef max
171
172 /**
173 * @brief This does what you think it does.
174 * @param a A thing of arbitrary type.
175 * @param b Another thing of arbitrary type.
176 * @return The lesser of the parameters.
177 *
178 * This is the simple classic generic implementation. It will work on
179 * temporary expressions, since they are only evaluated once, unlike a
180 * preprocessor macro.
181 */
182 template<typename _Tp>
183 inline const _Tp&
184 min(const _Tp& __a, const _Tp& __b)
185 {
186 // concept requirements
187 __glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
188 //return __b < __a ? __b : __a;
189 if (__b < __a)
190 return __b;
191 return __a;
192 }
193
194 /**
195 * @brief This does what you think it does.
196 * @param a A thing of arbitrary type.
197 * @param b Another thing of arbitrary type.
198 * @return The greater of the parameters.
199 *
200 * This is the simple classic generic implementation. It will work on
201 * temporary expressions, since they are only evaluated once, unlike a
202 * preprocessor macro.
203 */
204 template<typename _Tp>
205 inline const _Tp&
206 max(const _Tp& __a, const _Tp& __b)
207 {
208 // concept requirements
209 __glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
210 //return __a < __b ? __b : __a;
211 if (__a < __b)
212 return __b;
213 return __a;
214 }
215
216 /**
217 * @brief This does what you think it does.
218 * @param a A thing of arbitrary type.
219 * @param b Another thing of arbitrary type.
220 * @param comp A @link s20_3_3_comparisons comparison functor@endlink.
221 * @return The lesser of the parameters.
222 *
223 * This will work on temporary expressions, since they are only evaluated
224 * once, unlike a preprocessor macro.
225 */
226 template<typename _Tp, typename _Compare>
227 inline const _Tp&
228 min(const _Tp& __a, const _Tp& __b, _Compare __comp)
229 {
230 //return __comp(__b, __a) ? __b : __a;
231 if (__comp(__b, __a))
232 return __b;
233 return __a;
234 }
235
236 /**
237 * @brief This does what you think it does.
238 * @param a A thing of arbitrary type.
239 * @param b Another thing of arbitrary type.
240 * @param comp A @link s20_3_3_comparisons comparison functor@endlink.
241 * @return The greater of the parameters.
242 *
243 * This will work on temporary expressions, since they are only evaluated
244 * once, unlike a preprocessor macro.
245 */
246 template<typename _Tp, typename _Compare>
247 inline const _Tp&
248 max(const _Tp& __a, const _Tp& __b, _Compare __comp)
249 {
250 //return __comp(__a, __b) ? __b : __a;
251 if (__comp(__a, __b))
252 return __b;
253 return __a;
254 }
255
256 // All of these auxiliary structs serve two purposes. (1) Replace
257 // calls to copy with memmove whenever possible. (Memmove, not memcpy,
258 // because the input and output ranges are permitted to overlap.)
259 // (2) If we're using random access iterators, then write the loop as
260 // a for loop with an explicit count.
261
262 template<bool, typename>
263 struct __copy
264 {
265 template<typename _II, typename _OI>
266 static _OI
267 copy(_II __first, _II __last, _OI __result)
268 {
269 for (; __first != __last; ++__result, ++__first)
270 *__result = *__first;
271 return __result;
272 }
273 };
274
275 template<bool _BoolType>
276 struct __copy<_BoolType, random_access_iterator_tag>
277 {
278 template<typename _II, typename _OI>
279 static _OI
280 copy(_II __first, _II __last, _OI __result)
281 {
282 typedef typename iterator_traits<_II>::difference_type _Distance;
283 for(_Distance __n = __last - __first; __n > 0; --__n)
284 {
285 *__result = *__first;
286 ++__first;
287 ++__result;
288 }
289 return __result;
290 }
291 };
292
293 template<>
294 struct __copy<true, random_access_iterator_tag>
295 {
296 template<typename _Tp>
297 static _Tp*
298 copy(const _Tp* __first, const _Tp* __last, _Tp* __result)
299 {
300 std::memmove(__result, __first, sizeof(_Tp) * (__last - __first));
301 return __result + (__last - __first);
302 }
303 };
304
305 template<typename _II, typename _OI>
306 inline _OI
307 __copy_aux(_II __first, _II __last, _OI __result)
308 {
309 typedef typename iterator_traits<_II>::value_type _ValueTypeI;
310 typedef typename iterator_traits<_OI>::value_type _ValueTypeO;
311 typedef typename iterator_traits<_II>::iterator_category _Category;
312 const bool __simple = (__is_scalar<_ValueTypeI>::__value
313 && __is_pointer<_II>::__value
314 && __is_pointer<_OI>::__value
315 && __are_same<_ValueTypeI, _ValueTypeO>::__value);
316
317 return std::__copy<__simple, _Category>::copy(__first, __last, __result);
318 }
319
320 template<bool, bool>
321 struct __copy_normal
322 {
323 template<typename _II, typename _OI>
324 static _OI
325 copy_n(_II __first, _II __last, _OI __result)
326 { return std::__copy_aux(__first, __last, __result); }
327 };
328
329 template<>
330 struct __copy_normal<true, false>
331 {
332 template<typename _II, typename _OI>
333 static _OI
334 copy_n(_II __first, _II __last, _OI __result)
335 { return std::__copy_aux(__first.base(), __last.base(), __result); }
336 };
337
338 template<>
339 struct __copy_normal<false, true>
340 {
341 template<typename _II, typename _OI>
342 static _OI
343 copy_n(_II __first, _II __last, _OI __result)
344 { return _OI(std::__copy_aux(__first, __last, __result.base())); }
345 };
346
347 template<>
348 struct __copy_normal<true, true>
349 {
350 template<typename _II, typename _OI>
351 static _OI
352 copy_n(_II __first, _II __last, _OI __result)
353 { return _OI(std::__copy_aux(__first.base(), __last.base(),
354 __result.base())); }
355 };
356
357 /**
358 * @brief Copies the range [first,last) into result.
359 * @param first An input iterator.
360 * @param last An input iterator.
361 * @param result An output iterator.
362 * @return result + (first - last)
363 *
364 * This inline function will boil down to a call to @c memmove whenever
365 * possible. Failing that, if random access iterators are passed, then the
366 * loop count will be known (and therefore a candidate for compiler
367 * optimizations such as unrolling). Result may not be contained within
368 * [first,last); the copy_backward function should be used instead.
369 *
370 * Note that the end of the output range is permitted to be contained
371 * within [first,last).
372 */
373 template<typename _InputIterator, typename _OutputIterator>
374 inline _OutputIterator
375 copy(_InputIterator __first, _InputIterator __last,
376 _OutputIterator __result)
377 {
378 // concept requirements
379 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
380 __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
381 typename iterator_traits<_InputIterator>::value_type>)
382 __glibcxx_requires_valid_range(__first, __last);
383
384 const bool __in = __is_normal_iterator<_InputIterator>::__value;
385 const bool __out = __is_normal_iterator<_OutputIterator>::__value;
386 return std::__copy_normal<__in, __out>::copy_n(__first, __last,
387 __result);
388 }
389
390 template<bool, typename>
391 struct __copy_backward
392 {
393 template<typename _BI1, typename _BI2>
394 static _BI2
395 copy_b(_BI1 __first, _BI1 __last, _BI2 __result)
396 {
397 while (__first != __last)
398 *--__result = *--__last;
399 return __result;
400 }
401 };
402
403 template<bool _BoolType>
404 struct __copy_backward<_BoolType, random_access_iterator_tag>
405 {
406 template<typename _BI1, typename _BI2>
407 static _BI2
408 copy_b(_BI1 __first, _BI1 __last, _BI2 __result)
409 {
410 typename iterator_traits<_BI1>::difference_type __n;
411 for (__n = __last - __first; __n > 0; --__n)
412 *--__result = *--__last;
413 return __result;
414 }
415 };
416
417 template<>
418 struct __copy_backward<true, random_access_iterator_tag>
419 {
420 template<typename _Tp>
421 static _Tp*
422 copy_b(const _Tp* __first, const _Tp* __last, _Tp* __result)
423 {
424 const ptrdiff_t _Num = __last - __first;
425 std::memmove(__result - _Num, __first, sizeof(_Tp) * _Num);
426 return __result - _Num;
427 }
428 };
429
430 template<typename _BI1, typename _BI2>
431 inline _BI2
432 __copy_backward_aux(_BI1 __first, _BI1 __last, _BI2 __result)
433 {
434 typedef typename iterator_traits<_BI1>::value_type _ValueType1;
435 typedef typename iterator_traits<_BI2>::value_type _ValueType2;
436 typedef typename iterator_traits<_BI1>::iterator_category _Category;
437 const bool __simple = (__is_scalar<_ValueType1>::__value
438 && __is_pointer<_BI1>::__value
439 && __is_pointer<_BI2>::__value
440 && __are_same<_ValueType1, _ValueType2>::__value);
441
442 return std::__copy_backward<__simple, _Category>::copy_b(__first, __last,
443 __result);
444 }
445
446 template<bool, bool>
447 struct __copy_backward_normal
448 {
449 template<typename _BI1, typename _BI2>
450 static _BI2
451 copy_b_n(_BI1 __first, _BI1 __last, _BI2 __result)
452 { return std::__copy_backward_aux(__first, __last, __result); }
453 };
454
455 template<>
456 struct __copy_backward_normal<true, false>
457 {
458 template<typename _BI1, typename _BI2>
459 static _BI2
460 copy_b_n(_BI1 __first, _BI1 __last, _BI2 __result)
461 { return std::__copy_backward_aux(__first.base(), __last.base(),
462 __result); }
463 };
464
465 template<>
466 struct __copy_backward_normal<false, true>
467 {
468 template<typename _BI1, typename _BI2>
469 static _BI2
470 copy_b_n(_BI1 __first, _BI1 __last, _BI2 __result)
471 { return _BI2(std::__copy_backward_aux(__first, __last,
472 __result.base())); }
473 };
474
475 template<>
476 struct __copy_backward_normal<true, true>
477 {
478 template<typename _BI1, typename _BI2>
479 static _BI2
480 copy_b_n(_BI1 __first, _BI1 __last, _BI2 __result)
481 { return _BI2(std::__copy_backward_aux(__first.base(), __last.base(),
482 __result.base())); }
483 };
484
485 /**
486 * @brief Copies the range [first,last) into result.
487 * @param first A bidirectional iterator.
488 * @param last A bidirectional iterator.
489 * @param result A bidirectional iterator.
490 * @return result - (first - last)
491 *
492 * The function has the same effect as copy, but starts at the end of the
493 * range and works its way to the start, returning the start of the result.
494 * This inline function will boil down to a call to @c memmove whenever
495 * possible. Failing that, if random access iterators are passed, then the
496 * loop count will be known (and therefore a candidate for compiler
497 * optimizations such as unrolling).
498 *
499 * Result may not be in the range [first,last). Use copy instead. Note
500 * that the start of the output range may overlap [first,last).
501 */
502 template <typename _BI1, typename _BI2>
503 inline _BI2
504 copy_backward(_BI1 __first, _BI1 __last, _BI2 __result)
505 {
506 // concept requirements
507 __glibcxx_function_requires(_BidirectionalIteratorConcept<_BI1>)
508 __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<_BI2>)
509 __glibcxx_function_requires(_ConvertibleConcept<
510 typename iterator_traits<_BI1>::value_type,
511 typename iterator_traits<_BI2>::value_type>)
512 __glibcxx_requires_valid_range(__first, __last);
513
514 const bool __bi1 = __is_normal_iterator<_BI1>::__value;
515 const bool __bi2 = __is_normal_iterator<_BI2>::__value;
516 return std::__copy_backward_normal<__bi1, __bi2>::copy_b_n(__first, __last,
517 __result);
518 }
519
520 template<bool>
521 struct __fill
522 {
523 template<typename _ForwardIterator, typename _Tp>
524 static void
525 fill(_ForwardIterator __first, _ForwardIterator __last,
526 const _Tp& __value)
527 {
528 for (; __first != __last; ++__first)
529 *__first = __value;
530 }
531 };
532
533 template<>
534 struct __fill<true>
535 {
536 template<typename _ForwardIterator, typename _Tp>
537 static void
538 fill(_ForwardIterator __first, _ForwardIterator __last,
539 const _Tp& __value)
540 {
541 const _Tp __tmp = __value;
542 for (; __first != __last; ++__first)
543 *__first = __tmp;
544 }
545 };
546
547 /**
548 * @brief Fills the range [first,last) with copies of value.
549 * @param first A forward iterator.
550 * @param last A forward iterator.
551 * @param value A reference-to-const of arbitrary type.
552 * @return Nothing.
553 *
554 * This function fills a range with copies of the same value. For one-byte
555 * types filling contiguous areas of memory, this becomes an inline call to
556 * @c memset.
557 */
558 template<typename _ForwardIterator, typename _Tp>
559 void
560 fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value)
561 {
562 // concept requirements
563 __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
564 _ForwardIterator>)
565 __glibcxx_requires_valid_range(__first, __last);
566
567 const bool __scalar = __is_scalar<_Tp>::__value;
568 std::__fill<__scalar>::fill(__first, __last, __value);
569 }
570
571 // Specialization: for one-byte types we can use memset.
572 inline void
573 fill(unsigned char* __first, unsigned char* __last, const unsigned char& __c)
574 {
575 __glibcxx_requires_valid_range(__first, __last);
576 const unsigned char __tmp = __c;
577 std::memset(__first, __tmp, __last - __first);
578 }
579
580 inline void
581 fill(signed char* __first, signed char* __last, const signed char& __c)
582 {
583 __glibcxx_requires_valid_range(__first, __last);
584 const signed char __tmp = __c;
585 std::memset(__first, static_cast<unsigned char>(__tmp), __last - __first);
586 }
587
588 inline void
589 fill(char* __first, char* __last, const char& __c)
590 {
591 __glibcxx_requires_valid_range(__first, __last);
592 const char __tmp = __c;
593 std::memset(__first, static_cast<unsigned char>(__tmp), __last - __first);
594 }
595
596 template<bool>
597 struct __fill_n
598 {
599 template<typename _OutputIterator, typename _Size, typename _Tp>
600 static _OutputIterator
601 fill_n(_OutputIterator __first, _Size __n, const _Tp& __value)
602 {
603 for (; __n > 0; --__n, ++__first)
604 *__first = __value;
605 return __first;
606 }
607 };
608
609 template<>
610 struct __fill_n<true>
611 {
612 template<typename _OutputIterator, typename _Size, typename _Tp>
613 static _OutputIterator
614 fill_n(_OutputIterator __first, _Size __n, const _Tp& __value)
615 {
616 const _Tp __tmp = __value;
617 for (; __n > 0; --__n, ++__first)
618 *__first = __tmp;
619 return __first;
620 }
621 };
622
623 /**
624 * @brief Fills the range [first,first+n) with copies of value.
625 * @param first An output iterator.
626 * @param n The count of copies to perform.
627 * @param value A reference-to-const of arbitrary type.
628 * @return The iterator at first+n.
629 *
630 * This function fills a range with copies of the same value. For one-byte
631 * types filling contiguous areas of memory, this becomes an inline call to
632 * @c memset.
633 */
634 template<typename _OutputIterator, typename _Size, typename _Tp>
635 _OutputIterator
636 fill_n(_OutputIterator __first, _Size __n, const _Tp& __value)
637 {
638 // concept requirements
639 __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, _Tp>)
640
641 const bool __scalar = __is_scalar<_Tp>::__value;
642 return std::__fill_n<__scalar>::fill_n(__first, __n, __value);
643 }
644
645 template<typename _Size>
646 inline unsigned char*
647 fill_n(unsigned char* __first, _Size __n, const unsigned char& __c)
648 {
649 std::fill(__first, __first + __n, __c);
650 return __first + __n;
651 }
652
653 template<typename _Size>
654 inline signed char*
655 fill_n(char* __first, _Size __n, const signed char& __c)
656 {
657 std::fill(__first, __first + __n, __c);
658 return __first + __n;
659 }
660
661 template<typename _Size>
662 inline char*
663 fill_n(char* __first, _Size __n, const char& __c)
664 {
665 std::fill(__first, __first + __n, __c);
666 return __first + __n;
667 }
668
669 /**
670 * @brief Finds the places in ranges which don't match.
671 * @param first1 An input iterator.
672 * @param last1 An input iterator.
673 * @param first2 An input iterator.
674 * @return A pair of iterators pointing to the first mismatch.
675 *
676 * This compares the elements of two ranges using @c == and returns a pair
677 * of iterators. The first iterator points into the first range, the
678 * second iterator points into the second range, and the elements pointed
679 * to by the iterators are not equal.
680 */
681 template<typename _InputIterator1, typename _InputIterator2>
682 pair<_InputIterator1, _InputIterator2>
683 mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
684 _InputIterator2 __first2)
685 {
686 // concept requirements
687 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
688 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
689 __glibcxx_function_requires(_EqualOpConcept<
690 typename iterator_traits<_InputIterator1>::value_type,
691 typename iterator_traits<_InputIterator2>::value_type>)
692 __glibcxx_requires_valid_range(__first1, __last1);
693
694 while (__first1 != __last1 && *__first1 == *__first2)
695 {
696 ++__first1;
697 ++__first2;
698 }
699 return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
700 }
701
702 /**
703 * @brief Finds the places in ranges which don't match.
704 * @param first1 An input iterator.
705 * @param last1 An input iterator.
706 * @param first2 An input iterator.
707 * @param binary_pred A binary predicate @link s20_3_1_base functor@endlink.
708 * @return A pair of iterators pointing to the first mismatch.
709 *
710 * This compares the elements of two ranges using the binary_pred
711 * parameter, and returns a pair
712 * of iterators. The first iterator points into the first range, the
713 * second iterator points into the second range, and the elements pointed
714 * to by the iterators are not equal.
715 */
716 template<typename _InputIterator1, typename _InputIterator2,
717 typename _BinaryPredicate>
718 pair<_InputIterator1, _InputIterator2>
719 mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
720 _InputIterator2 __first2, _BinaryPredicate __binary_pred)
721 {
722 // concept requirements
723 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
724 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
725 __glibcxx_requires_valid_range(__first1, __last1);
726
727 while (__first1 != __last1 && __binary_pred(*__first1, *__first2))
728 {
729 ++__first1;
730 ++__first2;
731 }
732 return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
733 }
734
735 /**
736 * @brief Tests a range for element-wise equality.
737 * @param first1 An input iterator.
738 * @param last1 An input iterator.
739 * @param first2 An input iterator.
740 * @return A boolean true or false.
741 *
742 * This compares the elements of two ranges using @c == and returns true or
743 * false depending on whether all of the corresponding elements of the
744 * ranges are equal.
745 */
746 template<typename _InputIterator1, typename _InputIterator2>
747 inline bool
748 equal(_InputIterator1 __first1, _InputIterator1 __last1,
749 _InputIterator2 __first2)
750 {
751 // concept requirements
752 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
753 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
754 __glibcxx_function_requires(_EqualOpConcept<
755 typename iterator_traits<_InputIterator1>::value_type,
756 typename iterator_traits<_InputIterator2>::value_type>)
757 __glibcxx_requires_valid_range(__first1, __last1);
758
759 for (; __first1 != __last1; ++__first1, ++__first2)
760 if (!(*__first1 == *__first2))
761 return false;
762 return true;
763 }
764
765 /**
766 * @brief Tests a range for element-wise equality.
767 * @param first1 An input iterator.
768 * @param last1 An input iterator.
769 * @param first2 An input iterator.
770 * @param binary_pred A binary predicate @link s20_3_1_base functor@endlink.
771 * @return A boolean true or false.
772 *
773 * This compares the elements of two ranges using the binary_pred
774 * parameter, and returns true or
775 * false depending on whether all of the corresponding elements of the
776 * ranges are equal.
777 */
778 template<typename _InputIterator1, typename _InputIterator2,
779 typename _BinaryPredicate>
780 inline bool
781 equal(_InputIterator1 __first1, _InputIterator1 __last1,
782 _InputIterator2 __first2,
783 _BinaryPredicate __binary_pred)
784 {
785 // concept requirements
786 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
787 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
788 __glibcxx_requires_valid_range(__first1, __last1);
789
790 for (; __first1 != __last1; ++__first1, ++__first2)
791 if (!__binary_pred(*__first1, *__first2))
792 return false;
793 return true;
794 }
795
796 /**
797 * @brief Performs "dictionary" comparison on ranges.
798 * @param first1 An input iterator.
799 * @param last1 An input iterator.
800 * @param first2 An input iterator.
801 * @param last2 An input iterator.
802 * @return A boolean true or false.
803 *
804 * "Returns true if the sequence of elements defined by the range
805 * [first1,last1) is lexicographically less than the sequence of elements
806 * defined by the range [first2,last2). Returns false otherwise."
807 * (Quoted from [25.3.8]/1.) If the iterators are all character pointers,
808 * then this is an inline call to @c memcmp.
809 */
810 template<typename _InputIterator1, typename _InputIterator2>
811 bool
812 lexicographical_compare(_InputIterator1 __first1, _InputIterator1 __last1,
813 _InputIterator2 __first2, _InputIterator2 __last2)
814 {
815 // concept requirements
816 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
817 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
818 __glibcxx_function_requires(_LessThanOpConcept<
819 typename iterator_traits<_InputIterator1>::value_type,
820 typename iterator_traits<_InputIterator2>::value_type>)
821 __glibcxx_function_requires(_LessThanOpConcept<
822 typename iterator_traits<_InputIterator2>::value_type,
823 typename iterator_traits<_InputIterator1>::value_type>)
824 __glibcxx_requires_valid_range(__first1, __last1);
825 __glibcxx_requires_valid_range(__first2, __last2);
826
827 for (; __first1 != __last1 && __first2 != __last2;
828 ++__first1, ++__first2)
829 {
830 if (*__first1 < *__first2)
831 return true;
832 if (*__first2 < *__first1)
833 return false;
834 }
835 return __first1 == __last1 && __first2 != __last2;
836 }
837
838 /**
839 * @brief Performs "dictionary" comparison on ranges.
840 * @param first1 An input iterator.
841 * @param last1 An input iterator.
842 * @param first2 An input iterator.
843 * @param last2 An input iterator.
844 * @param comp A @link s20_3_3_comparisons comparison functor@endlink.
845 * @return A boolean true or false.
846 *
847 * The same as the four-parameter @c lexigraphical_compare, but uses the
848 * comp parameter instead of @c <.
849 */
850 template<typename _InputIterator1, typename _InputIterator2,
851 typename _Compare>
852 bool
853 lexicographical_compare(_InputIterator1 __first1, _InputIterator1 __last1,
854 _InputIterator2 __first2, _InputIterator2 __last2,
855 _Compare __comp)
856 {
857 // concept requirements
858 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
859 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
860 __glibcxx_requires_valid_range(__first1, __last1);
861 __glibcxx_requires_valid_range(__first2, __last2);
862
863 for (; __first1 != __last1 && __first2 != __last2;
864 ++__first1, ++__first2)
865 {
866 if (__comp(*__first1, *__first2))
867 return true;
868 if (__comp(*__first2, *__first1))
869 return false;
870 }
871 return __first1 == __last1 && __first2 != __last2;
872 }
873
874 inline bool
875 lexicographical_compare(const unsigned char* __first1,
876 const unsigned char* __last1,
877 const unsigned char* __first2,
878 const unsigned char* __last2)
879 {
880 __glibcxx_requires_valid_range(__first1, __last1);
881 __glibcxx_requires_valid_range(__first2, __last2);
882
883 const size_t __len1 = __last1 - __first1;
884 const size_t __len2 = __last2 - __first2;
885 const int __result = std::memcmp(__first1, __first2,
886 std::min(__len1, __len2));
887 return __result != 0 ? __result < 0 : __len1 < __len2;
888 }
889
890 inline bool
891 lexicographical_compare(const char* __first1, const char* __last1,
892 const char* __first2, const char* __last2)
893 {
894 __glibcxx_requires_valid_range(__first1, __last1);
895 __glibcxx_requires_valid_range(__first2, __last2);
896
897 #if CHAR_MAX == SCHAR_MAX
898 return std::lexicographical_compare((const signed char*) __first1,
899 (const signed char*) __last1,
900 (const signed char*) __first2,
901 (const signed char*) __last2);
902 #else /* CHAR_MAX == SCHAR_MAX */
903 return std::lexicographical_compare((const unsigned char*) __first1,
904 (const unsigned char*) __last1,
905 (const unsigned char*) __first2,
906 (const unsigned char*) __last2);
907 #endif /* CHAR_MAX == SCHAR_MAX */
908 }
909
910 } // namespace std
911
912 #endif