libstdc++
stl_algobase.h
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1// Core algorithmic facilities -*- C++ -*-
2
3// Copyright (C) 2001-2022 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
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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
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18// 3.1, as published by the Free Software Foundation.
19
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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
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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) 1996-1998
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_algobase.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_ALGOBASE_H
57#define _STL_ALGOBASE_H 1
58
59#include <bits/c++config.h>
60#include <bits/functexcept.h>
61#include <bits/cpp_type_traits.h>
62#include <ext/type_traits.h>
63#include <ext/numeric_traits.h>
64#include <bits/stl_pair.h>
65#include <bits/stl_iterator_base_types.h>
66#include <bits/stl_iterator_base_funcs.h>
67#include <bits/stl_iterator.h>
68#include <bits/concept_check.h>
69#include <debug/debug.h>
70#include <bits/move.h> // For std::swap
71#include <bits/predefined_ops.h>
72#if __cplusplus >= 201103L
73# include <type_traits>
74#endif
75#if __cplusplus > 201703L
76# include <compare>
77#endif
78
79namespace std _GLIBCXX_VISIBILITY(default)
80{
81_GLIBCXX_BEGIN_NAMESPACE_VERSION
82
83 /*
84 * A constexpr wrapper for __builtin_memcmp.
85 * @param __num The number of elements of type _Tp (not bytes).
86 */
87 template<typename _Tp, typename _Up>
88 _GLIBCXX14_CONSTEXPR
89 inline int
90 __memcmp(const _Tp* __first1, const _Up* __first2, size_t __num)
91 {
92#if __cplusplus >= 201103L
93 static_assert(sizeof(_Tp) == sizeof(_Up), "can be compared with memcmp");
94#endif
95#ifdef __cpp_lib_is_constant_evaluated
96 if (std::is_constant_evaluated())
97 {
98 for(; __num > 0; ++__first1, ++__first2, --__num)
99 if (*__first1 != *__first2)
100 return *__first1 < *__first2 ? -1 : 1;
101 return 0;
102 }
103 else
104#endif
105 return __builtin_memcmp(__first1, __first2, sizeof(_Tp) * __num);
106 }
107
108#if __cplusplus < 201103L
109 // See http://gcc.gnu.org/ml/libstdc++/2004-08/msg00167.html: in a
110 // nutshell, we are partially implementing the resolution of DR 187,
111 // when it's safe, i.e., the value_types are equal.
112 template<bool _BoolType>
113 struct __iter_swap
114 {
115 template<typename _ForwardIterator1, typename _ForwardIterator2>
116 static void
117 iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
118 {
119 typedef typename iterator_traits<_ForwardIterator1>::value_type
120 _ValueType1;
121 _ValueType1 __tmp = *__a;
122 *__a = *__b;
123 *__b = __tmp;
124 }
125 };
126
127 template<>
128 struct __iter_swap<true>
129 {
130 template<typename _ForwardIterator1, typename _ForwardIterator2>
131 static void
132 iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
133 {
134 swap(*__a, *__b);
135 }
136 };
137#endif // C++03
138
139 /**
140 * @brief Swaps the contents of two iterators.
141 * @ingroup mutating_algorithms
142 * @param __a An iterator.
143 * @param __b Another iterator.
144 * @return Nothing.
145 *
146 * This function swaps the values pointed to by two iterators, not the
147 * iterators themselves.
148 */
149 template<typename _ForwardIterator1, typename _ForwardIterator2>
150 _GLIBCXX20_CONSTEXPR
151 inline void
152 iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
153 {
154 // concept requirements
155 __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
156 _ForwardIterator1>)
157 __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
158 _ForwardIterator2>)
159
160#if __cplusplus < 201103L
161 typedef typename iterator_traits<_ForwardIterator1>::value_type
162 _ValueType1;
163 typedef typename iterator_traits<_ForwardIterator2>::value_type
164 _ValueType2;
165
166 __glibcxx_function_requires(_ConvertibleConcept<_ValueType1,
167 _ValueType2>)
168 __glibcxx_function_requires(_ConvertibleConcept<_ValueType2,
169 _ValueType1>)
170
171 typedef typename iterator_traits<_ForwardIterator1>::reference
172 _ReferenceType1;
173 typedef typename iterator_traits<_ForwardIterator2>::reference
174 _ReferenceType2;
175 std::__iter_swap<__are_same<_ValueType1, _ValueType2>::__value
176 && __are_same<_ValueType1&, _ReferenceType1>::__value
177 && __are_same<_ValueType2&, _ReferenceType2>::__value>::
178 iter_swap(__a, __b);
179#else
180 // _GLIBCXX_RESOLVE_LIB_DEFECTS
181 // 187. iter_swap underspecified
182 swap(*__a, *__b);
183#endif
184 }
185
186 /**
187 * @brief Swap the elements of two sequences.
188 * @ingroup mutating_algorithms
189 * @param __first1 A forward iterator.
190 * @param __last1 A forward iterator.
191 * @param __first2 A forward iterator.
192 * @return An iterator equal to @p first2+(last1-first1).
193 *
194 * Swaps each element in the range @p [first1,last1) with the
195 * corresponding element in the range @p [first2,(last1-first1)).
196 * The ranges must not overlap.
197 */
198 template<typename _ForwardIterator1, typename _ForwardIterator2>
199 _GLIBCXX20_CONSTEXPR
200 _ForwardIterator2
201 swap_ranges(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
202 _ForwardIterator2 __first2)
203 {
204 // concept requirements
205 __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
206 _ForwardIterator1>)
207 __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
208 _ForwardIterator2>)
209 __glibcxx_requires_valid_range(__first1, __last1);
210
211 for (; __first1 != __last1; ++__first1, (void)++__first2)
212 std::iter_swap(__first1, __first2);
213 return __first2;
214 }
215
216 /**
217 * @brief This does what you think it does.
218 * @ingroup sorting_algorithms
219 * @param __a A thing of arbitrary type.
220 * @param __b Another thing of arbitrary type.
221 * @return The lesser of the parameters.
222 *
223 * This is the simple classic generic implementation. It will work on
224 * temporary expressions, since they are only evaluated once, unlike a
225 * preprocessor macro.
226 */
227 template<typename _Tp>
228 _GLIBCXX14_CONSTEXPR
229 inline const _Tp&
230 min(const _Tp& __a, const _Tp& __b)
231 {
232 // concept requirements
233 __glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
234 //return __b < __a ? __b : __a;
235 if (__b < __a)
236 return __b;
237 return __a;
238 }
239
240 /**
241 * @brief This does what you think it does.
242 * @ingroup sorting_algorithms
243 * @param __a A thing of arbitrary type.
244 * @param __b Another thing of arbitrary type.
245 * @return The greater of the parameters.
246 *
247 * This is the simple classic generic implementation. It will work on
248 * temporary expressions, since they are only evaluated once, unlike a
249 * preprocessor macro.
250 */
251 template<typename _Tp>
252 _GLIBCXX14_CONSTEXPR
253 inline const _Tp&
254 max(const _Tp& __a, const _Tp& __b)
255 {
256 // concept requirements
257 __glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
258 //return __a < __b ? __b : __a;
259 if (__a < __b)
260 return __b;
261 return __a;
262 }
263
264 /**
265 * @brief This does what you think it does.
266 * @ingroup sorting_algorithms
267 * @param __a A thing of arbitrary type.
268 * @param __b Another thing of arbitrary type.
269 * @param __comp A @link comparison_functors comparison functor@endlink.
270 * @return The lesser of the parameters.
271 *
272 * This will work on temporary expressions, since they are only evaluated
273 * once, unlike a preprocessor macro.
274 */
275 template<typename _Tp, typename _Compare>
276 _GLIBCXX14_CONSTEXPR
277 inline const _Tp&
278 min(const _Tp& __a, const _Tp& __b, _Compare __comp)
279 {
280 //return __comp(__b, __a) ? __b : __a;
281 if (__comp(__b, __a))
282 return __b;
283 return __a;
284 }
285
286 /**
287 * @brief This does what you think it does.
288 * @ingroup sorting_algorithms
289 * @param __a A thing of arbitrary type.
290 * @param __b Another thing of arbitrary type.
291 * @param __comp A @link comparison_functors comparison functor@endlink.
292 * @return The greater of the parameters.
293 *
294 * This will work on temporary expressions, since they are only evaluated
295 * once, unlike a preprocessor macro.
296 */
297 template<typename _Tp, typename _Compare>
298 _GLIBCXX14_CONSTEXPR
299 inline const _Tp&
300 max(const _Tp& __a, const _Tp& __b, _Compare __comp)
301 {
302 //return __comp(__a, __b) ? __b : __a;
303 if (__comp(__a, __b))
304 return __b;
305 return __a;
306 }
307
308 // Fallback implementation of the function in bits/stl_iterator.h used to
309 // remove the __normal_iterator wrapper. See copy, fill, ...
310 template<typename _Iterator>
311 _GLIBCXX20_CONSTEXPR
312 inline _Iterator
313 __niter_base(_Iterator __it)
314 _GLIBCXX_NOEXCEPT_IF(std::is_nothrow_copy_constructible<_Iterator>::value)
315 { return __it; }
316
317 template<typename _Ite, typename _Seq>
318 _Ite
319 __niter_base(const ::__gnu_debug::_Safe_iterator<_Ite, _Seq,
320 std::random_access_iterator_tag>&);
321
322 // Reverse the __niter_base transformation to get a
323 // __normal_iterator back again (this assumes that __normal_iterator
324 // is only used to wrap random access iterators, like pointers).
325 template<typename _From, typename _To>
326 _GLIBCXX20_CONSTEXPR
327 inline _From
328 __niter_wrap(_From __from, _To __res)
329 { return __from + (__res - std::__niter_base(__from)); }
330
331 // No need to wrap, iterator already has the right type.
332 template<typename _Iterator>
333 _GLIBCXX20_CONSTEXPR
334 inline _Iterator
335 __niter_wrap(const _Iterator&, _Iterator __res)
336 { return __res; }
337
338 // All of these auxiliary structs serve two purposes. (1) Replace
339 // calls to copy with memmove whenever possible. (Memmove, not memcpy,
340 // because the input and output ranges are permitted to overlap.)
341 // (2) If we're using random access iterators, then write the loop as
342 // a for loop with an explicit count.
343
344 template<bool _IsMove, bool _IsSimple, typename _Category>
345 struct __copy_move
346 {
347 template<typename _II, typename _OI>
348 _GLIBCXX20_CONSTEXPR
349 static _OI
350 __copy_m(_II __first, _II __last, _OI __result)
351 {
352 for (; __first != __last; ++__result, (void)++__first)
353 *__result = *__first;
354 return __result;
355 }
356 };
357
358#if __cplusplus >= 201103L
359 template<typename _Category>
360 struct __copy_move<true, false, _Category>
361 {
362 template<typename _II, typename _OI>
363 _GLIBCXX20_CONSTEXPR
364 static _OI
365 __copy_m(_II __first, _II __last, _OI __result)
366 {
367 for (; __first != __last; ++__result, (void)++__first)
368 *__result = std::move(*__first);
369 return __result;
370 }
371 };
372#endif
373
374 template<>
375 struct __copy_move<false, false, random_access_iterator_tag>
376 {
377 template<typename _II, typename _OI>
378 _GLIBCXX20_CONSTEXPR
379 static _OI
380 __copy_m(_II __first, _II __last, _OI __result)
381 {
382 typedef typename iterator_traits<_II>::difference_type _Distance;
383 for(_Distance __n = __last - __first; __n > 0; --__n)
384 {
385 *__result = *__first;
386 ++__first;
387 ++__result;
388 }
389 return __result;
390 }
391 };
392
393#if __cplusplus >= 201103L
394 template<>
395 struct __copy_move<true, false, random_access_iterator_tag>
396 {
397 template<typename _II, typename _OI>
398 _GLIBCXX20_CONSTEXPR
399 static _OI
400 __copy_m(_II __first, _II __last, _OI __result)
401 {
402 typedef typename iterator_traits<_II>::difference_type _Distance;
403 for(_Distance __n = __last - __first; __n > 0; --__n)
404 {
405 *__result = std::move(*__first);
406 ++__first;
407 ++__result;
408 }
409 return __result;
410 }
411 };
412#endif
413
414 template<bool _IsMove>
415 struct __copy_move<_IsMove, true, random_access_iterator_tag>
416 {
417 template<typename _Tp>
418 _GLIBCXX20_CONSTEXPR
419 static _Tp*
420 __copy_m(const _Tp* __first, const _Tp* __last, _Tp* __result)
421 {
422#if __cplusplus >= 201103L
423 using __assignable = __conditional_t<_IsMove,
424 is_move_assignable<_Tp>,
425 is_copy_assignable<_Tp>>;
426 // trivial types can have deleted assignment
427 static_assert( __assignable::value, "type must be assignable" );
428#endif
429 const ptrdiff_t _Num = __last - __first;
430 if (_Num)
431 __builtin_memmove(__result, __first, sizeof(_Tp) * _Num);
432 return __result + _Num;
433 }
434 };
435
436_GLIBCXX_BEGIN_NAMESPACE_CONTAINER
437
438 template<typename _Tp, typename _Ref, typename _Ptr>
439 struct _Deque_iterator;
440
441 struct _Bit_iterator;
442
443_GLIBCXX_END_NAMESPACE_CONTAINER
444
445 // Helpers for streambuf iterators (either istream or ostream).
446 // NB: avoid including <iosfwd>, relatively large.
447 template<typename _CharT>
448 struct char_traits;
449
450 template<typename _CharT, typename _Traits>
451 class istreambuf_iterator;
452
453 template<typename _CharT, typename _Traits>
454 class ostreambuf_iterator;
455
456 template<bool _IsMove, typename _CharT>
457 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
458 ostreambuf_iterator<_CharT, char_traits<_CharT> > >::__type
459 __copy_move_a2(_CharT*, _CharT*,
460 ostreambuf_iterator<_CharT, char_traits<_CharT> >);
461
462 template<bool _IsMove, typename _CharT>
463 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
464 ostreambuf_iterator<_CharT, char_traits<_CharT> > >::__type
465 __copy_move_a2(const _CharT*, const _CharT*,
466 ostreambuf_iterator<_CharT, char_traits<_CharT> >);
467
468 template<bool _IsMove, typename _CharT>
469 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
470 _CharT*>::__type
471 __copy_move_a2(istreambuf_iterator<_CharT, char_traits<_CharT> >,
472 istreambuf_iterator<_CharT, char_traits<_CharT> >, _CharT*);
473
474 template<bool _IsMove, typename _CharT>
475 typename __gnu_cxx::__enable_if<
476 __is_char<_CharT>::__value,
477 _GLIBCXX_STD_C::_Deque_iterator<_CharT, _CharT&, _CharT*> >::__type
478 __copy_move_a2(
479 istreambuf_iterator<_CharT, char_traits<_CharT> >,
480 istreambuf_iterator<_CharT, char_traits<_CharT> >,
481 _GLIBCXX_STD_C::_Deque_iterator<_CharT, _CharT&, _CharT*>);
482
483 template<bool _IsMove, typename _II, typename _OI>
484 _GLIBCXX20_CONSTEXPR
485 inline _OI
486 __copy_move_a2(_II __first, _II __last, _OI __result)
487 {
488 typedef typename iterator_traits<_II>::iterator_category _Category;
489#ifdef __cpp_lib_is_constant_evaluated
490 if (std::is_constant_evaluated())
491 return std::__copy_move<_IsMove, false, _Category>::
492 __copy_m(__first, __last, __result);
493#endif
494 return std::__copy_move<_IsMove, __memcpyable<_OI, _II>::__value,
495 _Category>::__copy_m(__first, __last, __result);
496 }
497
498 template<bool _IsMove,
499 typename _Tp, typename _Ref, typename _Ptr, typename _OI>
500 _OI
501 __copy_move_a1(_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
502 _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
503 _OI);
504
505 template<bool _IsMove,
506 typename _ITp, typename _IRef, typename _IPtr, typename _OTp>
507 _GLIBCXX_STD_C::_Deque_iterator<_OTp, _OTp&, _OTp*>
508 __copy_move_a1(_GLIBCXX_STD_C::_Deque_iterator<_ITp, _IRef, _IPtr>,
509 _GLIBCXX_STD_C::_Deque_iterator<_ITp, _IRef, _IPtr>,
510 _GLIBCXX_STD_C::_Deque_iterator<_OTp, _OTp&, _OTp*>);
511
512 template<bool _IsMove, typename _II, typename _Tp>
513 typename __gnu_cxx::__enable_if<
514 __is_random_access_iter<_II>::__value,
515 _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*> >::__type
516 __copy_move_a1(_II, _II, _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*>);
517
518 template<bool _IsMove, typename _II, typename _OI>
519 _GLIBCXX20_CONSTEXPR
520 inline _OI
521 __copy_move_a1(_II __first, _II __last, _OI __result)
522 { return std::__copy_move_a2<_IsMove>(__first, __last, __result); }
523
524 template<bool _IsMove, typename _II, typename _OI>
525 _GLIBCXX20_CONSTEXPR
526 inline _OI
527 __copy_move_a(_II __first, _II __last, _OI __result)
528 {
529 return std::__niter_wrap(__result,
530 std::__copy_move_a1<_IsMove>(std::__niter_base(__first),
531 std::__niter_base(__last),
532 std::__niter_base(__result)));
533 }
534
535 template<bool _IsMove,
536 typename _Ite, typename _Seq, typename _Cat, typename _OI>
537 _OI
538 __copy_move_a(const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
539 const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
540 _OI);
541
542 template<bool _IsMove,
543 typename _II, typename _Ite, typename _Seq, typename _Cat>
544 __gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>
545 __copy_move_a(_II, _II,
546 const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&);
547
548 template<bool _IsMove,
549 typename _IIte, typename _ISeq, typename _ICat,
550 typename _OIte, typename _OSeq, typename _OCat>
551 ::__gnu_debug::_Safe_iterator<_OIte, _OSeq, _OCat>
552 __copy_move_a(const ::__gnu_debug::_Safe_iterator<_IIte, _ISeq, _ICat>&,
553 const ::__gnu_debug::_Safe_iterator<_IIte, _ISeq, _ICat>&,
554 const ::__gnu_debug::_Safe_iterator<_OIte, _OSeq, _OCat>&);
555
556 template<typename _InputIterator, typename _Size, typename _OutputIterator>
557 _GLIBCXX20_CONSTEXPR
558 _OutputIterator
559 __copy_n_a(_InputIterator __first, _Size __n, _OutputIterator __result,
560 bool)
561 {
562 if (__n > 0)
563 {
564 while (true)
565 {
566 *__result = *__first;
567 ++__result;
568 if (--__n > 0)
569 ++__first;
570 else
571 break;
572 }
573 }
574 return __result;
575 }
576
577 template<typename _CharT, typename _Size>
578 typename __gnu_cxx::__enable_if<
579 __is_char<_CharT>::__value, _CharT*>::__type
580 __copy_n_a(istreambuf_iterator<_CharT, char_traits<_CharT> >,
581 _Size, _CharT*, bool);
582
583 template<typename _CharT, typename _Size>
584 typename __gnu_cxx::__enable_if<
585 __is_char<_CharT>::__value,
586 _GLIBCXX_STD_C::_Deque_iterator<_CharT, _CharT&, _CharT*> >::__type
587 __copy_n_a(istreambuf_iterator<_CharT, char_traits<_CharT> >, _Size,
588 _GLIBCXX_STD_C::_Deque_iterator<_CharT, _CharT&, _CharT*>,
589 bool);
590
591 /**
592 * @brief Copies the range [first,last) into result.
593 * @ingroup mutating_algorithms
594 * @param __first An input iterator.
595 * @param __last An input iterator.
596 * @param __result An output iterator.
597 * @return result + (last - first)
598 *
599 * This inline function will boil down to a call to @c memmove whenever
600 * possible. Failing that, if random access iterators are passed, then the
601 * loop count will be known (and therefore a candidate for compiler
602 * optimizations such as unrolling). Result may not be contained within
603 * [first,last); the copy_backward function should be used instead.
604 *
605 * Note that the end of the output range is permitted to be contained
606 * within [first,last).
607 */
608 template<typename _II, typename _OI>
609 _GLIBCXX20_CONSTEXPR
610 inline _OI
611 copy(_II __first, _II __last, _OI __result)
612 {
613 // concept requirements
614 __glibcxx_function_requires(_InputIteratorConcept<_II>)
615 __glibcxx_function_requires(_OutputIteratorConcept<_OI,
616 typename iterator_traits<_II>::reference>)
617 __glibcxx_requires_can_increment_range(__first, __last, __result);
618
619 return std::__copy_move_a<__is_move_iterator<_II>::__value>
620 (std::__miter_base(__first), std::__miter_base(__last), __result);
621 }
622
623#if __cplusplus >= 201103L
624 /**
625 * @brief Moves the range [first,last) into result.
626 * @ingroup mutating_algorithms
627 * @param __first An input iterator.
628 * @param __last An input iterator.
629 * @param __result An output iterator.
630 * @return result + (last - first)
631 *
632 * This inline function will boil down to a call to @c memmove whenever
633 * possible. Failing that, if random access iterators are passed, then the
634 * loop count will be known (and therefore a candidate for compiler
635 * optimizations such as unrolling). Result may not be contained within
636 * [first,last); the move_backward function should be used instead.
637 *
638 * Note that the end of the output range is permitted to be contained
639 * within [first,last).
640 */
641 template<typename _II, typename _OI>
642 _GLIBCXX20_CONSTEXPR
643 inline _OI
644 move(_II __first, _II __last, _OI __result)
645 {
646 // concept requirements
647 __glibcxx_function_requires(_InputIteratorConcept<_II>)
648 __glibcxx_function_requires(_OutputIteratorConcept<_OI,
649 typename iterator_traits<_II>::value_type&&>)
650 __glibcxx_requires_can_increment_range(__first, __last, __result);
651
652 return std::__copy_move_a<true>(std::__miter_base(__first),
653 std::__miter_base(__last), __result);
654 }
655
656#define _GLIBCXX_MOVE3(_Tp, _Up, _Vp) std::move(_Tp, _Up, _Vp)
657#else
658#define _GLIBCXX_MOVE3(_Tp, _Up, _Vp) std::copy(_Tp, _Up, _Vp)
659#endif
660
661 template<bool _IsMove, bool _IsSimple, typename _Category>
662 struct __copy_move_backward
663 {
664 template<typename _BI1, typename _BI2>
665 _GLIBCXX20_CONSTEXPR
666 static _BI2
667 __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
668 {
669 while (__first != __last)
670 *--__result = *--__last;
671 return __result;
672 }
673 };
674
675#if __cplusplus >= 201103L
676 template<typename _Category>
677 struct __copy_move_backward<true, false, _Category>
678 {
679 template<typename _BI1, typename _BI2>
680 _GLIBCXX20_CONSTEXPR
681 static _BI2
682 __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
683 {
684 while (__first != __last)
685 *--__result = std::move(*--__last);
686 return __result;
687 }
688 };
689#endif
690
691 template<>
692 struct __copy_move_backward<false, false, random_access_iterator_tag>
693 {
694 template<typename _BI1, typename _BI2>
695 _GLIBCXX20_CONSTEXPR
696 static _BI2
697 __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
698 {
699 typename iterator_traits<_BI1>::difference_type
700 __n = __last - __first;
701 for (; __n > 0; --__n)
702 *--__result = *--__last;
703 return __result;
704 }
705 };
706
707#if __cplusplus >= 201103L
708 template<>
709 struct __copy_move_backward<true, false, random_access_iterator_tag>
710 {
711 template<typename _BI1, typename _BI2>
712 _GLIBCXX20_CONSTEXPR
713 static _BI2
714 __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
715 {
716 typename iterator_traits<_BI1>::difference_type
717 __n = __last - __first;
718 for (; __n > 0; --__n)
719 *--__result = std::move(*--__last);
720 return __result;
721 }
722 };
723#endif
724
725 template<bool _IsMove>
726 struct __copy_move_backward<_IsMove, true, random_access_iterator_tag>
727 {
728 template<typename _Tp>
729 _GLIBCXX20_CONSTEXPR
730 static _Tp*
731 __copy_move_b(const _Tp* __first, const _Tp* __last, _Tp* __result)
732 {
733#if __cplusplus >= 201103L
734 using __assignable = __conditional_t<_IsMove,
735 is_move_assignable<_Tp>,
736 is_copy_assignable<_Tp>>;
737 // trivial types can have deleted assignment
738 static_assert( __assignable::value, "type must be assignable" );
739#endif
740 const ptrdiff_t _Num = __last - __first;
741 if (_Num)
742 __builtin_memmove(__result - _Num, __first, sizeof(_Tp) * _Num);
743 return __result - _Num;
744 }
745 };
746
747 template<bool _IsMove, typename _BI1, typename _BI2>
748 _GLIBCXX20_CONSTEXPR
749 inline _BI2
750 __copy_move_backward_a2(_BI1 __first, _BI1 __last, _BI2 __result)
751 {
752 typedef typename iterator_traits<_BI1>::iterator_category _Category;
753#ifdef __cpp_lib_is_constant_evaluated
754 if (std::is_constant_evaluated())
755 return std::__copy_move_backward<_IsMove, false, _Category>::
756 __copy_move_b(__first, __last, __result);
757#endif
758 return std::__copy_move_backward<_IsMove,
759 __memcpyable<_BI2, _BI1>::__value,
760 _Category>::__copy_move_b(__first,
761 __last,
762 __result);
763 }
764
765 template<bool _IsMove, typename _BI1, typename _BI2>
766 _GLIBCXX20_CONSTEXPR
767 inline _BI2
768 __copy_move_backward_a1(_BI1 __first, _BI1 __last, _BI2 __result)
769 { return std::__copy_move_backward_a2<_IsMove>(__first, __last, __result); }
770
771 template<bool _IsMove,
772 typename _Tp, typename _Ref, typename _Ptr, typename _OI>
773 _OI
774 __copy_move_backward_a1(_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
775 _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
776 _OI);
777
778 template<bool _IsMove,
779 typename _ITp, typename _IRef, typename _IPtr, typename _OTp>
780 _GLIBCXX_STD_C::_Deque_iterator<_OTp, _OTp&, _OTp*>
781 __copy_move_backward_a1(
782 _GLIBCXX_STD_C::_Deque_iterator<_ITp, _IRef, _IPtr>,
783 _GLIBCXX_STD_C::_Deque_iterator<_ITp, _IRef, _IPtr>,
784 _GLIBCXX_STD_C::_Deque_iterator<_OTp, _OTp&, _OTp*>);
785
786 template<bool _IsMove, typename _II, typename _Tp>
787 typename __gnu_cxx::__enable_if<
788 __is_random_access_iter<_II>::__value,
789 _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*> >::__type
790 __copy_move_backward_a1(_II, _II,
791 _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*>);
792
793 template<bool _IsMove, typename _II, typename _OI>
794 _GLIBCXX20_CONSTEXPR
795 inline _OI
796 __copy_move_backward_a(_II __first, _II __last, _OI __result)
797 {
798 return std::__niter_wrap(__result,
799 std::__copy_move_backward_a1<_IsMove>
800 (std::__niter_base(__first), std::__niter_base(__last),
801 std::__niter_base(__result)));
802 }
803
804 template<bool _IsMove,
805 typename _Ite, typename _Seq, typename _Cat, typename _OI>
806 _OI
807 __copy_move_backward_a(
808 const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
809 const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
810 _OI);
811
812 template<bool _IsMove,
813 typename _II, typename _Ite, typename _Seq, typename _Cat>
814 __gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>
815 __copy_move_backward_a(_II, _II,
816 const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&);
817
818 template<bool _IsMove,
819 typename _IIte, typename _ISeq, typename _ICat,
820 typename _OIte, typename _OSeq, typename _OCat>
821 ::__gnu_debug::_Safe_iterator<_OIte, _OSeq, _OCat>
822 __copy_move_backward_a(
823 const ::__gnu_debug::_Safe_iterator<_IIte, _ISeq, _ICat>&,
824 const ::__gnu_debug::_Safe_iterator<_IIte, _ISeq, _ICat>&,
825 const ::__gnu_debug::_Safe_iterator<_OIte, _OSeq, _OCat>&);
826
827 /**
828 * @brief Copies the range [first,last) into result.
829 * @ingroup mutating_algorithms
830 * @param __first A bidirectional iterator.
831 * @param __last A bidirectional iterator.
832 * @param __result A bidirectional iterator.
833 * @return result - (last - first)
834 *
835 * The function has the same effect as copy, but starts at the end of the
836 * range and works its way to the start, returning the start of the result.
837 * This inline function will boil down to a call to @c memmove whenever
838 * possible. Failing that, if random access iterators are passed, then the
839 * loop count will be known (and therefore a candidate for compiler
840 * optimizations such as unrolling).
841 *
842 * Result may not be in the range (first,last]. Use copy instead. Note
843 * that the start of the output range may overlap [first,last).
844 */
845 template<typename _BI1, typename _BI2>
846 _GLIBCXX20_CONSTEXPR
847 inline _BI2
848 copy_backward(_BI1 __first, _BI1 __last, _BI2 __result)
849 {
850 // concept requirements
851 __glibcxx_function_requires(_BidirectionalIteratorConcept<_BI1>)
852 __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<_BI2>)
853 __glibcxx_function_requires(_OutputIteratorConcept<_BI2,
854 typename iterator_traits<_BI1>::reference>)
855 __glibcxx_requires_can_decrement_range(__first, __last, __result);
856
857 return std::__copy_move_backward_a<__is_move_iterator<_BI1>::__value>
858 (std::__miter_base(__first), std::__miter_base(__last), __result);
859 }
860
861#if __cplusplus >= 201103L
862 /**
863 * @brief Moves the range [first,last) into result.
864 * @ingroup mutating_algorithms
865 * @param __first A bidirectional iterator.
866 * @param __last A bidirectional iterator.
867 * @param __result A bidirectional iterator.
868 * @return result - (last - first)
869 *
870 * The function has the same effect as move, but starts at the end of the
871 * range and works its way to the start, returning the start of the result.
872 * This inline function will boil down to a call to @c memmove whenever
873 * possible. Failing that, if random access iterators are passed, then the
874 * loop count will be known (and therefore a candidate for compiler
875 * optimizations such as unrolling).
876 *
877 * Result may not be in the range (first,last]. Use move instead. Note
878 * that the start of the output range may overlap [first,last).
879 */
880 template<typename _BI1, typename _BI2>
881 _GLIBCXX20_CONSTEXPR
882 inline _BI2
883 move_backward(_BI1 __first, _BI1 __last, _BI2 __result)
884 {
885 // concept requirements
886 __glibcxx_function_requires(_BidirectionalIteratorConcept<_BI1>)
887 __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<_BI2>)
888 __glibcxx_function_requires(_OutputIteratorConcept<_BI2,
889 typename iterator_traits<_BI1>::value_type&&>)
890 __glibcxx_requires_can_decrement_range(__first, __last, __result);
891
892 return std::__copy_move_backward_a<true>(std::__miter_base(__first),
893 std::__miter_base(__last),
894 __result);
895 }
896
897#define _GLIBCXX_MOVE_BACKWARD3(_Tp, _Up, _Vp) std::move_backward(_Tp, _Up, _Vp)
898#else
899#define _GLIBCXX_MOVE_BACKWARD3(_Tp, _Up, _Vp) std::copy_backward(_Tp, _Up, _Vp)
900#endif
901
902 template<typename _ForwardIterator, typename _Tp>
903 _GLIBCXX20_CONSTEXPR
904 inline typename
905 __gnu_cxx::__enable_if<!__is_scalar<_Tp>::__value, void>::__type
906 __fill_a1(_ForwardIterator __first, _ForwardIterator __last,
907 const _Tp& __value)
908 {
909 for (; __first != __last; ++__first)
910 *__first = __value;
911 }
912
913 template<typename _ForwardIterator, typename _Tp>
914 _GLIBCXX20_CONSTEXPR
915 inline typename
916 __gnu_cxx::__enable_if<__is_scalar<_Tp>::__value, void>::__type
917 __fill_a1(_ForwardIterator __first, _ForwardIterator __last,
918 const _Tp& __value)
919 {
920 const _Tp __tmp = __value;
921 for (; __first != __last; ++__first)
922 *__first = __tmp;
923 }
924
925 // Specialization: for char types we can use memset.
926 template<typename _Tp>
927 _GLIBCXX20_CONSTEXPR
928 inline typename
929 __gnu_cxx::__enable_if<__is_byte<_Tp>::__value, void>::__type
930 __fill_a1(_Tp* __first, _Tp* __last, const _Tp& __c)
931 {
932 const _Tp __tmp = __c;
933#if __cpp_lib_is_constant_evaluated
934 if (std::is_constant_evaluated())
935 {
936 for (; __first != __last; ++__first)
937 *__first = __tmp;
938 return;
939 }
940#endif
941 if (const size_t __len = __last - __first)
942 __builtin_memset(__first, static_cast<unsigned char>(__tmp), __len);
943 }
944
945 template<typename _Ite, typename _Cont, typename _Tp>
946 _GLIBCXX20_CONSTEXPR
947 inline void
948 __fill_a1(::__gnu_cxx::__normal_iterator<_Ite, _Cont> __first,
949 ::__gnu_cxx::__normal_iterator<_Ite, _Cont> __last,
950 const _Tp& __value)
951 { std::__fill_a1(__first.base(), __last.base(), __value); }
952
953 template<typename _Tp, typename _VTp>
954 void
955 __fill_a1(const _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*>&,
956 const _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*>&,
957 const _VTp&);
958
959 _GLIBCXX20_CONSTEXPR
960 void
961 __fill_a1(_GLIBCXX_STD_C::_Bit_iterator, _GLIBCXX_STD_C::_Bit_iterator,
962 const bool&);
963
964 template<typename _FIte, typename _Tp>
965 _GLIBCXX20_CONSTEXPR
966 inline void
967 __fill_a(_FIte __first, _FIte __last, const _Tp& __value)
968 { std::__fill_a1(__first, __last, __value); }
969
970 template<typename _Ite, typename _Seq, typename _Cat, typename _Tp>
971 void
972 __fill_a(const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
973 const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
974 const _Tp&);
975
976 /**
977 * @brief Fills the range [first,last) with copies of value.
978 * @ingroup mutating_algorithms
979 * @param __first A forward iterator.
980 * @param __last A forward iterator.
981 * @param __value A reference-to-const of arbitrary type.
982 * @return Nothing.
983 *
984 * This function fills a range with copies of the same value. For char
985 * types filling contiguous areas of memory, this becomes an inline call
986 * to @c memset or @c wmemset.
987 */
988 template<typename _ForwardIterator, typename _Tp>
989 _GLIBCXX20_CONSTEXPR
990 inline void
991 fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value)
992 {
993 // concept requirements
994 __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
995 _ForwardIterator>)
996 __glibcxx_requires_valid_range(__first, __last);
997
998 std::__fill_a(__first, __last, __value);
999 }
1000
1001 // Used by fill_n, generate_n, etc. to convert _Size to an integral type:
1002 inline _GLIBCXX_CONSTEXPR int
1003 __size_to_integer(int __n) { return __n; }
1004 inline _GLIBCXX_CONSTEXPR unsigned
1005 __size_to_integer(unsigned __n) { return __n; }
1006 inline _GLIBCXX_CONSTEXPR long
1007 __size_to_integer(long __n) { return __n; }
1008 inline _GLIBCXX_CONSTEXPR unsigned long
1009 __size_to_integer(unsigned long __n) { return __n; }
1010 inline _GLIBCXX_CONSTEXPR long long
1011 __size_to_integer(long long __n) { return __n; }
1012 inline _GLIBCXX_CONSTEXPR unsigned long long
1013 __size_to_integer(unsigned long long __n) { return __n; }
1014
1015#if defined(__GLIBCXX_TYPE_INT_N_0)
1016 __extension__ inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_0
1017 __size_to_integer(__GLIBCXX_TYPE_INT_N_0 __n) { return __n; }
1018 __extension__ inline _GLIBCXX_CONSTEXPR unsigned __GLIBCXX_TYPE_INT_N_0
1019 __size_to_integer(unsigned __GLIBCXX_TYPE_INT_N_0 __n) { return __n; }
1020#endif
1021#if defined(__GLIBCXX_TYPE_INT_N_1)
1022 __extension__ inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_1
1023 __size_to_integer(__GLIBCXX_TYPE_INT_N_1 __n) { return __n; }
1024 __extension__ inline _GLIBCXX_CONSTEXPR unsigned __GLIBCXX_TYPE_INT_N_1
1025 __size_to_integer(unsigned __GLIBCXX_TYPE_INT_N_1 __n) { return __n; }
1026#endif
1027#if defined(__GLIBCXX_TYPE_INT_N_2)
1028 __extension__ inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_2
1029 __size_to_integer(__GLIBCXX_TYPE_INT_N_2 __n) { return __n; }
1030 __extension__ inline _GLIBCXX_CONSTEXPR unsigned __GLIBCXX_TYPE_INT_N_2
1031 __size_to_integer(unsigned __GLIBCXX_TYPE_INT_N_2 __n) { return __n; }
1032#endif
1033#if defined(__GLIBCXX_TYPE_INT_N_3)
1034 __extension__ inline _GLIBCXX_CONSTEXPR unsigned __GLIBCXX_TYPE_INT_N_3
1035 __size_to_integer(__GLIBCXX_TYPE_INT_N_3 __n) { return __n; }
1036 __extension__ inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_3
1037 __size_to_integer(unsigned __GLIBCXX_TYPE_INT_N_3 __n) { return __n; }
1038#endif
1039
1040 inline _GLIBCXX_CONSTEXPR long long
1041 __size_to_integer(float __n) { return (long long)__n; }
1042 inline _GLIBCXX_CONSTEXPR long long
1043 __size_to_integer(double __n) { return (long long)__n; }
1044 inline _GLIBCXX_CONSTEXPR long long
1045 __size_to_integer(long double __n) { return (long long)__n; }
1046#if !defined(__STRICT_ANSI__) && defined(_GLIBCXX_USE_FLOAT128)
1047 __extension__ inline _GLIBCXX_CONSTEXPR long long
1048 __size_to_integer(__float128 __n) { return (long long)__n; }
1049#endif
1050
1051 template<typename _OutputIterator, typename _Size, typename _Tp>
1052 _GLIBCXX20_CONSTEXPR
1053 inline typename
1054 __gnu_cxx::__enable_if<!__is_scalar<_Tp>::__value, _OutputIterator>::__type
1055 __fill_n_a1(_OutputIterator __first, _Size __n, const _Tp& __value)
1056 {
1057 for (; __n > 0; --__n, (void) ++__first)
1058 *__first = __value;
1059 return __first;
1060 }
1061
1062 template<typename _OutputIterator, typename _Size, typename _Tp>
1063 _GLIBCXX20_CONSTEXPR
1064 inline typename
1065 __gnu_cxx::__enable_if<__is_scalar<_Tp>::__value, _OutputIterator>::__type
1066 __fill_n_a1(_OutputIterator __first, _Size __n, const _Tp& __value)
1067 {
1068 const _Tp __tmp = __value;
1069 for (; __n > 0; --__n, (void) ++__first)
1070 *__first = __tmp;
1071 return __first;
1072 }
1073
1074 template<typename _Ite, typename _Seq, typename _Cat, typename _Size,
1075 typename _Tp>
1076 ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>
1077 __fill_n_a(const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>& __first,
1078 _Size __n, const _Tp& __value,
1079 std::input_iterator_tag);
1080
1081 template<typename _OutputIterator, typename _Size, typename _Tp>
1082 _GLIBCXX20_CONSTEXPR
1083 inline _OutputIterator
1084 __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value,
1085 std::output_iterator_tag)
1086 {
1087#if __cplusplus >= 201103L
1088 static_assert(is_integral<_Size>{}, "fill_n must pass integral size");
1089#endif
1090 return __fill_n_a1(__first, __n, __value);
1091 }
1092
1093 template<typename _OutputIterator, typename _Size, typename _Tp>
1094 _GLIBCXX20_CONSTEXPR
1095 inline _OutputIterator
1096 __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value,
1097 std::input_iterator_tag)
1098 {
1099#if __cplusplus >= 201103L
1100 static_assert(is_integral<_Size>{}, "fill_n must pass integral size");
1101#endif
1102 return __fill_n_a1(__first, __n, __value);
1103 }
1104
1105 template<typename _OutputIterator, typename _Size, typename _Tp>
1106 _GLIBCXX20_CONSTEXPR
1107 inline _OutputIterator
1108 __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value,
1109 std::random_access_iterator_tag)
1110 {
1111#if __cplusplus >= 201103L
1112 static_assert(is_integral<_Size>{}, "fill_n must pass integral size");
1113#endif
1114 if (__n <= 0)
1115 return __first;
1116
1117 __glibcxx_requires_can_increment(__first, __n);
1118
1119 std::__fill_a(__first, __first + __n, __value);
1120 return __first + __n;
1121 }
1122
1123 /**
1124 * @brief Fills the range [first,first+n) with copies of value.
1125 * @ingroup mutating_algorithms
1126 * @param __first An output iterator.
1127 * @param __n The count of copies to perform.
1128 * @param __value A reference-to-const of arbitrary type.
1129 * @return The iterator at first+n.
1130 *
1131 * This function fills a range with copies of the same value. For char
1132 * types filling contiguous areas of memory, this becomes an inline call
1133 * to @c memset or @c wmemset.
1134 *
1135 * If @p __n is negative, the function does nothing.
1136 */
1137 // _GLIBCXX_RESOLVE_LIB_DEFECTS
1138 // DR 865. More algorithms that throw away information
1139 // DR 426. search_n(), fill_n(), and generate_n() with negative n
1140 template<typename _OI, typename _Size, typename _Tp>
1141 _GLIBCXX20_CONSTEXPR
1142 inline _OI
1143 fill_n(_OI __first, _Size __n, const _Tp& __value)
1144 {
1145 // concept requirements
1146 __glibcxx_function_requires(_OutputIteratorConcept<_OI, const _Tp&>)
1147
1148 return std::__fill_n_a(__first, std::__size_to_integer(__n), __value,
1149 std::__iterator_category(__first));
1150 }
1151
1152 template<bool _BoolType>
1153 struct __equal
1154 {
1155 template<typename _II1, typename _II2>
1156 _GLIBCXX20_CONSTEXPR
1157 static bool
1158 equal(_II1 __first1, _II1 __last1, _II2 __first2)
1159 {
1160 for (; __first1 != __last1; ++__first1, (void) ++__first2)
1161 if (!(*__first1 == *__first2))
1162 return false;
1163 return true;
1164 }
1165 };
1166
1167 template<>
1168 struct __equal<true>
1169 {
1170 template<typename _Tp>
1171 _GLIBCXX20_CONSTEXPR
1172 static bool
1173 equal(const _Tp* __first1, const _Tp* __last1, const _Tp* __first2)
1174 {
1175 if (const size_t __len = (__last1 - __first1))
1176 return !std::__memcmp(__first1, __first2, __len);
1177 return true;
1178 }
1179 };
1180
1181 template<typename _Tp, typename _Ref, typename _Ptr, typename _II>
1182 typename __gnu_cxx::__enable_if<
1183 __is_random_access_iter<_II>::__value, bool>::__type
1184 __equal_aux1(_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
1185 _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
1186 _II);
1187
1188 template<typename _Tp1, typename _Ref1, typename _Ptr1,
1189 typename _Tp2, typename _Ref2, typename _Ptr2>
1190 bool
1191 __equal_aux1(_GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
1192 _GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
1193 _GLIBCXX_STD_C::_Deque_iterator<_Tp2, _Ref2, _Ptr2>);
1194
1195 template<typename _II, typename _Tp, typename _Ref, typename _Ptr>
1196 typename __gnu_cxx::__enable_if<
1197 __is_random_access_iter<_II>::__value, bool>::__type
1198 __equal_aux1(_II, _II,
1199 _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>);
1200
1201 template<typename _II1, typename _II2>
1202 _GLIBCXX20_CONSTEXPR
1203 inline bool
1204 __equal_aux1(_II1 __first1, _II1 __last1, _II2 __first2)
1205 {
1206 typedef typename iterator_traits<_II1>::value_type _ValueType1;
1207 const bool __simple = ((__is_integer<_ValueType1>::__value
1208 || __is_pointer<_ValueType1>::__value)
1209 && __memcmpable<_II1, _II2>::__value);
1210 return std::__equal<__simple>::equal(__first1, __last1, __first2);
1211 }
1212
1213 template<typename _II1, typename _II2>
1214 _GLIBCXX20_CONSTEXPR
1215 inline bool
1216 __equal_aux(_II1 __first1, _II1 __last1, _II2 __first2)
1217 {
1218 return std::__equal_aux1(std::__niter_base(__first1),
1219 std::__niter_base(__last1),
1220 std::__niter_base(__first2));
1221 }
1222
1223 template<typename _II1, typename _Seq1, typename _Cat1, typename _II2>
1224 bool
1225 __equal_aux(const ::__gnu_debug::_Safe_iterator<_II1, _Seq1, _Cat1>&,
1226 const ::__gnu_debug::_Safe_iterator<_II1, _Seq1, _Cat1>&,
1227 _II2);
1228
1229 template<typename _II1, typename _II2, typename _Seq2, typename _Cat2>
1230 bool
1231 __equal_aux(_II1, _II1,
1232 const ::__gnu_debug::_Safe_iterator<_II2, _Seq2, _Cat2>&);
1233
1234 template<typename _II1, typename _Seq1, typename _Cat1,
1235 typename _II2, typename _Seq2, typename _Cat2>
1236 bool
1237 __equal_aux(const ::__gnu_debug::_Safe_iterator<_II1, _Seq1, _Cat1>&,
1238 const ::__gnu_debug::_Safe_iterator<_II1, _Seq1, _Cat1>&,
1239 const ::__gnu_debug::_Safe_iterator<_II2, _Seq2, _Cat2>&);
1240
1241 template<typename, typename>
1242 struct __lc_rai
1243 {
1244 template<typename _II1, typename _II2>
1245 _GLIBCXX20_CONSTEXPR
1246 static _II1
1247 __newlast1(_II1, _II1 __last1, _II2, _II2)
1248 { return __last1; }
1249
1250 template<typename _II>
1251 _GLIBCXX20_CONSTEXPR
1252 static bool
1253 __cnd2(_II __first, _II __last)
1254 { return __first != __last; }
1255 };
1256
1257 template<>
1258 struct __lc_rai<random_access_iterator_tag, random_access_iterator_tag>
1259 {
1260 template<typename _RAI1, typename _RAI2>
1261 _GLIBCXX20_CONSTEXPR
1262 static _RAI1
1263 __newlast1(_RAI1 __first1, _RAI1 __last1,
1264 _RAI2 __first2, _RAI2 __last2)
1265 {
1266 const typename iterator_traits<_RAI1>::difference_type
1267 __diff1 = __last1 - __first1;
1268 const typename iterator_traits<_RAI2>::difference_type
1269 __diff2 = __last2 - __first2;
1270 return __diff2 < __diff1 ? __first1 + __diff2 : __last1;
1271 }
1272
1273 template<typename _RAI>
1274 static _GLIBCXX20_CONSTEXPR bool
1275 __cnd2(_RAI, _RAI)
1276 { return true; }
1277 };
1278
1279 template<typename _II1, typename _II2, typename _Compare>
1280 _GLIBCXX20_CONSTEXPR
1281 bool
1282 __lexicographical_compare_impl(_II1 __first1, _II1 __last1,
1283 _II2 __first2, _II2 __last2,
1284 _Compare __comp)
1285 {
1286 typedef typename iterator_traits<_II1>::iterator_category _Category1;
1287 typedef typename iterator_traits<_II2>::iterator_category _Category2;
1288 typedef std::__lc_rai<_Category1, _Category2> __rai_type;
1289
1290 __last1 = __rai_type::__newlast1(__first1, __last1, __first2, __last2);
1291 for (; __first1 != __last1 && __rai_type::__cnd2(__first2, __last2);
1292 ++__first1, (void)++__first2)
1293 {
1294 if (__comp(__first1, __first2))
1295 return true;
1296 if (__comp(__first2, __first1))
1297 return false;
1298 }
1299 return __first1 == __last1 && __first2 != __last2;
1300 }
1301
1302 template<bool _BoolType>
1303 struct __lexicographical_compare
1304 {
1305 template<typename _II1, typename _II2>
1306 _GLIBCXX20_CONSTEXPR
1307 static bool
1308 __lc(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
1309 {
1310 using __gnu_cxx::__ops::__iter_less_iter;
1311 return std::__lexicographical_compare_impl(__first1, __last1,
1312 __first2, __last2,
1313 __iter_less_iter());
1314 }
1315
1316 template<typename _II1, typename _II2>
1317 _GLIBCXX20_CONSTEXPR
1318 static int
1319 __3way(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
1320 {
1321 while (__first1 != __last1)
1322 {
1323 if (__first2 == __last2)
1324 return +1;
1325 if (*__first1 < *__first2)
1326 return -1;
1327 if (*__first2 < *__first1)
1328 return +1;
1329 ++__first1;
1330 ++__first2;
1331 }
1332 return int(__first2 == __last2) - 1;
1333 }
1334 };
1335
1336 template<>
1337 struct __lexicographical_compare<true>
1338 {
1339 template<typename _Tp, typename _Up>
1340 _GLIBCXX20_CONSTEXPR
1341 static bool
1342 __lc(const _Tp* __first1, const _Tp* __last1,
1343 const _Up* __first2, const _Up* __last2)
1344 { return __3way(__first1, __last1, __first2, __last2) < 0; }
1345
1346 template<typename _Tp, typename _Up>
1347 _GLIBCXX20_CONSTEXPR
1348 static ptrdiff_t
1349 __3way(const _Tp* __first1, const _Tp* __last1,
1350 const _Up* __first2, const _Up* __last2)
1351 {
1352 const size_t __len1 = __last1 - __first1;
1353 const size_t __len2 = __last2 - __first2;
1354 if (const size_t __len = std::min(__len1, __len2))
1355 if (int __result = std::__memcmp(__first1, __first2, __len))
1356 return __result;
1357 return ptrdiff_t(__len1 - __len2);
1358 }
1359 };
1360
1361 template<typename _II1, typename _II2>
1362 _GLIBCXX20_CONSTEXPR
1363 inline bool
1364 __lexicographical_compare_aux1(_II1 __first1, _II1 __last1,
1365 _II2 __first2, _II2 __last2)
1366 {
1367 typedef typename iterator_traits<_II1>::value_type _ValueType1;
1368 typedef typename iterator_traits<_II2>::value_type _ValueType2;
1369 const bool __simple =
1370 (__is_memcmp_ordered_with<_ValueType1, _ValueType2>::__value
1371 && __is_pointer<_II1>::__value
1372 && __is_pointer<_II2>::__value
1373#if __cplusplus > 201703L && __cpp_lib_concepts
1374 // For C++20 iterator_traits<volatile T*>::value_type is non-volatile
1375 // so __is_byte<T> could be true, but we can't use memcmp with
1376 // volatile data.
1377 && !is_volatile_v<remove_reference_t<iter_reference_t<_II1>>>
1378 && !is_volatile_v<remove_reference_t<iter_reference_t<_II2>>>
1379#endif
1380 );
1381
1382 return std::__lexicographical_compare<__simple>::__lc(__first1, __last1,
1383 __first2, __last2);
1384 }
1385
1386 template<typename _Tp1, typename _Ref1, typename _Ptr1,
1387 typename _Tp2>
1388 bool
1389 __lexicographical_compare_aux1(
1390 _GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
1391 _GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
1392 _Tp2*, _Tp2*);
1393
1394 template<typename _Tp1,
1395 typename _Tp2, typename _Ref2, typename _Ptr2>
1396 bool
1397 __lexicographical_compare_aux1(_Tp1*, _Tp1*,
1398 _GLIBCXX_STD_C::_Deque_iterator<_Tp2, _Ref2, _Ptr2>,
1399 _GLIBCXX_STD_C::_Deque_iterator<_Tp2, _Ref2, _Ptr2>);
1400
1401 template<typename _Tp1, typename _Ref1, typename _Ptr1,
1402 typename _Tp2, typename _Ref2, typename _Ptr2>
1403 bool
1404 __lexicographical_compare_aux1(
1405 _GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
1406 _GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
1407 _GLIBCXX_STD_C::_Deque_iterator<_Tp2, _Ref2, _Ptr2>,
1408 _GLIBCXX_STD_C::_Deque_iterator<_Tp2, _Ref2, _Ptr2>);
1409
1410 template<typename _II1, typename _II2>
1411 _GLIBCXX20_CONSTEXPR
1412 inline bool
1413 __lexicographical_compare_aux(_II1 __first1, _II1 __last1,
1414 _II2 __first2, _II2 __last2)
1415 {
1416 return std::__lexicographical_compare_aux1(std::__niter_base(__first1),
1417 std::__niter_base(__last1),
1418 std::__niter_base(__first2),
1419 std::__niter_base(__last2));
1420 }
1421
1422 template<typename _Iter1, typename _Seq1, typename _Cat1,
1423 typename _II2>
1424 bool
1425 __lexicographical_compare_aux(
1426 const ::__gnu_debug::_Safe_iterator<_Iter1, _Seq1, _Cat1>&,
1427 const ::__gnu_debug::_Safe_iterator<_Iter1, _Seq1, _Cat1>&,
1428 _II2, _II2);
1429
1430 template<typename _II1,
1431 typename _Iter2, typename _Seq2, typename _Cat2>
1432 bool
1433 __lexicographical_compare_aux(
1434 _II1, _II1,
1435 const ::__gnu_debug::_Safe_iterator<_Iter2, _Seq2, _Cat2>&,
1436 const ::__gnu_debug::_Safe_iterator<_Iter2, _Seq2, _Cat2>&);
1437
1438 template<typename _Iter1, typename _Seq1, typename _Cat1,
1439 typename _Iter2, typename _Seq2, typename _Cat2>
1440 bool
1441 __lexicographical_compare_aux(
1442 const ::__gnu_debug::_Safe_iterator<_Iter1, _Seq1, _Cat1>&,
1443 const ::__gnu_debug::_Safe_iterator<_Iter1, _Seq1, _Cat1>&,
1444 const ::__gnu_debug::_Safe_iterator<_Iter2, _Seq2, _Cat2>&,
1445 const ::__gnu_debug::_Safe_iterator<_Iter2, _Seq2, _Cat2>&);
1446
1447 template<typename _ForwardIterator, typename _Tp, typename _Compare>
1448 _GLIBCXX20_CONSTEXPR
1449 _ForwardIterator
1450 __lower_bound(_ForwardIterator __first, _ForwardIterator __last,
1451 const _Tp& __val, _Compare __comp)
1452 {
1453 typedef typename iterator_traits<_ForwardIterator>::difference_type
1454 _DistanceType;
1455
1456 _DistanceType __len = std::distance(__first, __last);
1457
1458 while (__len > 0)
1459 {
1460 _DistanceType __half = __len >> 1;
1461 _ForwardIterator __middle = __first;
1462 std::advance(__middle, __half);
1463 if (__comp(__middle, __val))
1464 {
1465 __first = __middle;
1466 ++__first;
1467 __len = __len - __half - 1;
1468 }
1469 else
1470 __len = __half;
1471 }
1472 return __first;
1473 }
1474
1475 /**
1476 * @brief Finds the first position in which @a val could be inserted
1477 * without changing the ordering.
1478 * @param __first An iterator.
1479 * @param __last Another iterator.
1480 * @param __val The search term.
1481 * @return An iterator pointing to the first element <em>not less
1482 * than</em> @a val, or end() if every element is less than
1483 * @a val.
1484 * @ingroup binary_search_algorithms
1485 */
1486 template<typename _ForwardIterator, typename _Tp>
1487 _GLIBCXX20_CONSTEXPR
1488 inline _ForwardIterator
1489 lower_bound(_ForwardIterator __first, _ForwardIterator __last,
1490 const _Tp& __val)
1491 {
1492 // concept requirements
1493 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
1494 __glibcxx_function_requires(_LessThanOpConcept<
1495 typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
1496 __glibcxx_requires_partitioned_lower(__first, __last, __val);
1497
1498 return std::__lower_bound(__first, __last, __val,
1499 __gnu_cxx::__ops::__iter_less_val());
1500 }
1501
1502 /// This is a helper function for the sort routines and for random.tcc.
1503 // Precondition: __n > 0.
1504 inline _GLIBCXX_CONSTEXPR int
1505 __lg(int __n)
1506 { return (int)sizeof(int) * __CHAR_BIT__ - 1 - __builtin_clz(__n); }
1507
1508 inline _GLIBCXX_CONSTEXPR unsigned
1509 __lg(unsigned __n)
1510 { return (int)sizeof(int) * __CHAR_BIT__ - 1 - __builtin_clz(__n); }
1511
1512 inline _GLIBCXX_CONSTEXPR long
1513 __lg(long __n)
1514 { return (int)sizeof(long) * __CHAR_BIT__ - 1 - __builtin_clzl(__n); }
1515
1516 inline _GLIBCXX_CONSTEXPR unsigned long
1517 __lg(unsigned long __n)
1518 { return (int)sizeof(long) * __CHAR_BIT__ - 1 - __builtin_clzl(__n); }
1519
1520 inline _GLIBCXX_CONSTEXPR long long
1521 __lg(long long __n)
1522 { return (int)sizeof(long long) * __CHAR_BIT__ - 1 - __builtin_clzll(__n); }
1523
1524 inline _GLIBCXX_CONSTEXPR unsigned long long
1525 __lg(unsigned long long __n)
1526 { return (int)sizeof(long long) * __CHAR_BIT__ - 1 - __builtin_clzll(__n); }
1527
1528_GLIBCXX_BEGIN_NAMESPACE_ALGO
1529
1530 /**
1531 * @brief Tests a range for element-wise equality.
1532 * @ingroup non_mutating_algorithms
1533 * @param __first1 An input iterator.
1534 * @param __last1 An input iterator.
1535 * @param __first2 An input iterator.
1536 * @return A boolean true or false.
1537 *
1538 * This compares the elements of two ranges using @c == and returns true or
1539 * false depending on whether all of the corresponding elements of the
1540 * ranges are equal.
1541 */
1542 template<typename _II1, typename _II2>
1543 _GLIBCXX20_CONSTEXPR
1544 inline bool
1545 equal(_II1 __first1, _II1 __last1, _II2 __first2)
1546 {
1547 // concept requirements
1548 __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1549 __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1550 __glibcxx_function_requires(_EqualOpConcept<
1551 typename iterator_traits<_II1>::value_type,
1552 typename iterator_traits<_II2>::value_type>)
1553 __glibcxx_requires_can_increment_range(__first1, __last1, __first2);
1554
1555 return std::__equal_aux(__first1, __last1, __first2);
1556 }
1557
1558 /**
1559 * @brief Tests a range for element-wise equality.
1560 * @ingroup non_mutating_algorithms
1561 * @param __first1 An input iterator.
1562 * @param __last1 An input iterator.
1563 * @param __first2 An input iterator.
1564 * @param __binary_pred A binary predicate @link functors
1565 * functor@endlink.
1566 * @return A boolean true or false.
1567 *
1568 * This compares the elements of two ranges using the binary_pred
1569 * parameter, and returns true or
1570 * false depending on whether all of the corresponding elements of the
1571 * ranges are equal.
1572 */
1573 template<typename _IIter1, typename _IIter2, typename _BinaryPredicate>
1574 _GLIBCXX20_CONSTEXPR
1575 inline bool
1576 equal(_IIter1 __first1, _IIter1 __last1,
1577 _IIter2 __first2, _BinaryPredicate __binary_pred)
1578 {
1579 // concept requirements
1580 __glibcxx_function_requires(_InputIteratorConcept<_IIter1>)
1581 __glibcxx_function_requires(_InputIteratorConcept<_IIter2>)
1582 __glibcxx_requires_valid_range(__first1, __last1);
1583
1584 for (; __first1 != __last1; ++__first1, (void)++__first2)
1585 if (!bool(__binary_pred(*__first1, *__first2)))
1586 return false;
1587 return true;
1588 }
1589
1590#if __cplusplus >= 201103L
1591 // 4-iterator version of std::equal<It1, It2> for use in C++11.
1592 template<typename _II1, typename _II2>
1593 _GLIBCXX20_CONSTEXPR
1594 inline bool
1595 __equal4(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
1596 {
1597 using _RATag = random_access_iterator_tag;
1598 using _Cat1 = typename iterator_traits<_II1>::iterator_category;
1599 using _Cat2 = typename iterator_traits<_II2>::iterator_category;
1600 using _RAIters = __and_<is_same<_Cat1, _RATag>, is_same<_Cat2, _RATag>>;
1601 if (_RAIters())
1602 {
1603 auto __d1 = std::distance(__first1, __last1);
1604 auto __d2 = std::distance(__first2, __last2);
1605 if (__d1 != __d2)
1606 return false;
1607 return _GLIBCXX_STD_A::equal(__first1, __last1, __first2);
1608 }
1609
1610 for (; __first1 != __last1 && __first2 != __last2;
1611 ++__first1, (void)++__first2)
1612 if (!(*__first1 == *__first2))
1613 return false;
1614 return __first1 == __last1 && __first2 == __last2;
1615 }
1616
1617 // 4-iterator version of std::equal<It1, It2, BinaryPred> for use in C++11.
1618 template<typename _II1, typename _II2, typename _BinaryPredicate>
1619 _GLIBCXX20_CONSTEXPR
1620 inline bool
1621 __equal4(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2,
1622 _BinaryPredicate __binary_pred)
1623 {
1624 using _RATag = random_access_iterator_tag;
1625 using _Cat1 = typename iterator_traits<_II1>::iterator_category;
1626 using _Cat2 = typename iterator_traits<_II2>::iterator_category;
1627 using _RAIters = __and_<is_same<_Cat1, _RATag>, is_same<_Cat2, _RATag>>;
1628 if (_RAIters())
1629 {
1630 auto __d1 = std::distance(__first1, __last1);
1631 auto __d2 = std::distance(__first2, __last2);
1632 if (__d1 != __d2)
1633 return false;
1634 return _GLIBCXX_STD_A::equal(__first1, __last1, __first2,
1635 __binary_pred);
1636 }
1637
1638 for (; __first1 != __last1 && __first2 != __last2;
1639 ++__first1, (void)++__first2)
1640 if (!bool(__binary_pred(*__first1, *__first2)))
1641 return false;
1642 return __first1 == __last1 && __first2 == __last2;
1643 }
1644#endif // C++11
1645
1646#if __cplusplus > 201103L
1647
1648#define __cpp_lib_robust_nonmodifying_seq_ops 201304L
1649
1650 /**
1651 * @brief Tests a range for element-wise equality.
1652 * @ingroup non_mutating_algorithms
1653 * @param __first1 An input iterator.
1654 * @param __last1 An input iterator.
1655 * @param __first2 An input iterator.
1656 * @param __last2 An input iterator.
1657 * @return A boolean true or false.
1658 *
1659 * This compares the elements of two ranges using @c == and returns true or
1660 * false depending on whether all of the corresponding elements of the
1661 * ranges are equal.
1662 */
1663 template<typename _II1, typename _II2>
1664 _GLIBCXX20_CONSTEXPR
1665 inline bool
1666 equal(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
1667 {
1668 // concept requirements
1669 __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1670 __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1671 __glibcxx_function_requires(_EqualOpConcept<
1672 typename iterator_traits<_II1>::value_type,
1673 typename iterator_traits<_II2>::value_type>)
1674 __glibcxx_requires_valid_range(__first1, __last1);
1675 __glibcxx_requires_valid_range(__first2, __last2);
1676
1677 return _GLIBCXX_STD_A::__equal4(__first1, __last1, __first2, __last2);
1678 }
1679
1680 /**
1681 * @brief Tests a range for element-wise equality.
1682 * @ingroup non_mutating_algorithms
1683 * @param __first1 An input iterator.
1684 * @param __last1 An input iterator.
1685 * @param __first2 An input iterator.
1686 * @param __last2 An input iterator.
1687 * @param __binary_pred A binary predicate @link functors
1688 * functor@endlink.
1689 * @return A boolean true or false.
1690 *
1691 * This compares the elements of two ranges using the binary_pred
1692 * parameter, and returns true or
1693 * false depending on whether all of the corresponding elements of the
1694 * ranges are equal.
1695 */
1696 template<typename _IIter1, typename _IIter2, typename _BinaryPredicate>
1697 _GLIBCXX20_CONSTEXPR
1698 inline bool
1699 equal(_IIter1 __first1, _IIter1 __last1,
1700 _IIter2 __first2, _IIter2 __last2, _BinaryPredicate __binary_pred)
1701 {
1702 // concept requirements
1703 __glibcxx_function_requires(_InputIteratorConcept<_IIter1>)
1704 __glibcxx_function_requires(_InputIteratorConcept<_IIter2>)
1705 __glibcxx_requires_valid_range(__first1, __last1);
1706 __glibcxx_requires_valid_range(__first2, __last2);
1707
1708 return _GLIBCXX_STD_A::__equal4(__first1, __last1, __first2, __last2,
1709 __binary_pred);
1710 }
1711#endif // C++14
1712
1713 /**
1714 * @brief Performs @b dictionary comparison on ranges.
1715 * @ingroup sorting_algorithms
1716 * @param __first1 An input iterator.
1717 * @param __last1 An input iterator.
1718 * @param __first2 An input iterator.
1719 * @param __last2 An input iterator.
1720 * @return A boolean true or false.
1721 *
1722 * <em>Returns true if the sequence of elements defined by the range
1723 * [first1,last1) is lexicographically less than the sequence of elements
1724 * defined by the range [first2,last2). Returns false otherwise.</em>
1725 * (Quoted from [25.3.8]/1.) If the iterators are all character pointers,
1726 * then this is an inline call to @c memcmp.
1727 */
1728 template<typename _II1, typename _II2>
1729 _GLIBCXX20_CONSTEXPR
1730 inline bool
1731 lexicographical_compare(_II1 __first1, _II1 __last1,
1732 _II2 __first2, _II2 __last2)
1733 {
1734#ifdef _GLIBCXX_CONCEPT_CHECKS
1735 // concept requirements
1736 typedef typename iterator_traits<_II1>::value_type _ValueType1;
1737 typedef typename iterator_traits<_II2>::value_type _ValueType2;
1738#endif
1739 __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1740 __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1741 __glibcxx_function_requires(_LessThanOpConcept<_ValueType1, _ValueType2>)
1742 __glibcxx_function_requires(_LessThanOpConcept<_ValueType2, _ValueType1>)
1743 __glibcxx_requires_valid_range(__first1, __last1);
1744 __glibcxx_requires_valid_range(__first2, __last2);
1745
1746 return std::__lexicographical_compare_aux(__first1, __last1,
1747 __first2, __last2);
1748 }
1749
1750 /**
1751 * @brief Performs @b dictionary comparison on ranges.
1752 * @ingroup sorting_algorithms
1753 * @param __first1 An input iterator.
1754 * @param __last1 An input iterator.
1755 * @param __first2 An input iterator.
1756 * @param __last2 An input iterator.
1757 * @param __comp A @link comparison_functors comparison functor@endlink.
1758 * @return A boolean true or false.
1759 *
1760 * The same as the four-parameter @c lexicographical_compare, but uses the
1761 * comp parameter instead of @c <.
1762 */
1763 template<typename _II1, typename _II2, typename _Compare>
1764 _GLIBCXX20_CONSTEXPR
1765 inline bool
1766 lexicographical_compare(_II1 __first1, _II1 __last1,
1767 _II2 __first2, _II2 __last2, _Compare __comp)
1768 {
1769 // concept requirements
1770 __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1771 __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1772 __glibcxx_requires_valid_range(__first1, __last1);
1773 __glibcxx_requires_valid_range(__first2, __last2);
1774
1775 return std::__lexicographical_compare_impl
1776 (__first1, __last1, __first2, __last2,
1777 __gnu_cxx::__ops::__iter_comp_iter(__comp));
1778 }
1779
1780#if __cpp_lib_three_way_comparison
1781 // Iter points to a contiguous range of unsigned narrow character type
1782 // or std::byte, suitable for comparison by memcmp.
1783 template<typename _Iter>
1784 concept __is_byte_iter = contiguous_iterator<_Iter>
1785 && __is_memcmp_ordered<iter_value_t<_Iter>>::__value;
1786
1787 // Return a struct with two members, initialized to the smaller of x and y
1788 // (or x if they compare equal) and the result of the comparison x <=> y.
1789 template<typename _Tp>
1790 constexpr auto
1791 __min_cmp(_Tp __x, _Tp __y)
1792 {
1793 struct _Res {
1794 _Tp _M_min;
1795 decltype(__x <=> __y) _M_cmp;
1796 };
1797 auto __c = __x <=> __y;
1798 if (__c > 0)
1799 return _Res{__y, __c};
1800 return _Res{__x, __c};
1801 }
1802
1803 /**
1804 * @brief Performs dictionary comparison on ranges.
1805 * @ingroup sorting_algorithms
1806 * @param __first1 An input iterator.
1807 * @param __last1 An input iterator.
1808 * @param __first2 An input iterator.
1809 * @param __last2 An input iterator.
1810 * @param __comp A @link comparison_functors comparison functor@endlink.
1811 * @return The comparison category that `__comp(*__first1, *__first2)`
1812 * returns.
1813 */
1814 template<typename _InputIter1, typename _InputIter2, typename _Comp>
1815 constexpr auto
1816 lexicographical_compare_three_way(_InputIter1 __first1,
1817 _InputIter1 __last1,
1818 _InputIter2 __first2,
1819 _InputIter2 __last2,
1820 _Comp __comp)
1821 -> decltype(__comp(*__first1, *__first2))
1822 {
1823 // concept requirements
1824 __glibcxx_function_requires(_InputIteratorConcept<_InputIter1>)
1825 __glibcxx_function_requires(_InputIteratorConcept<_InputIter2>)
1826 __glibcxx_requires_valid_range(__first1, __last1);
1827 __glibcxx_requires_valid_range(__first2, __last2);
1828
1829 using _Cat = decltype(__comp(*__first1, *__first2));
1830 static_assert(same_as<common_comparison_category_t<_Cat>, _Cat>);
1831
1832 if (!std::__is_constant_evaluated())
1833 if constexpr (same_as<_Comp, __detail::_Synth3way>
1834 || same_as<_Comp, compare_three_way>)
1835 if constexpr (__is_byte_iter<_InputIter1>)
1836 if constexpr (__is_byte_iter<_InputIter2>)
1837 {
1838 const auto [__len, __lencmp] = _GLIBCXX_STD_A::
1839 __min_cmp(__last1 - __first1, __last2 - __first2);
1840 if (__len)
1841 {
1842 const auto __c
1843 = __builtin_memcmp(&*__first1, &*__first2, __len) <=> 0;
1844 if (__c != 0)
1845 return __c;
1846 }
1847 return __lencmp;
1848 }
1849
1850 while (__first1 != __last1)
1851 {
1852 if (__first2 == __last2)
1853 return strong_ordering::greater;
1854 if (auto __cmp = __comp(*__first1, *__first2); __cmp != 0)
1855 return __cmp;
1856 ++__first1;
1857 ++__first2;
1858 }
1859 return (__first2 == __last2) <=> true; // See PR 94006
1860 }
1861
1862 template<typename _InputIter1, typename _InputIter2>
1863 constexpr auto
1864 lexicographical_compare_three_way(_InputIter1 __first1,
1865 _InputIter1 __last1,
1866 _InputIter2 __first2,
1867 _InputIter2 __last2)
1868 {
1869 return _GLIBCXX_STD_A::
1870 lexicographical_compare_three_way(__first1, __last1, __first2, __last2,
1871 compare_three_way{});
1872 }
1873#endif // three_way_comparison
1874
1875 template<typename _InputIterator1, typename _InputIterator2,
1876 typename _BinaryPredicate>
1877 _GLIBCXX20_CONSTEXPR
1878 pair<_InputIterator1, _InputIterator2>
1879 __mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1880 _InputIterator2 __first2, _BinaryPredicate __binary_pred)
1881 {
1882 while (__first1 != __last1 && __binary_pred(__first1, __first2))
1883 {
1884 ++__first1;
1885 ++__first2;
1886 }
1887 return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
1888 }
1889
1890 /**
1891 * @brief Finds the places in ranges which don't match.
1892 * @ingroup non_mutating_algorithms
1893 * @param __first1 An input iterator.
1894 * @param __last1 An input iterator.
1895 * @param __first2 An input iterator.
1896 * @return A pair of iterators pointing to the first mismatch.
1897 *
1898 * This compares the elements of two ranges using @c == and returns a pair
1899 * of iterators. The first iterator points into the first range, the
1900 * second iterator points into the second range, and the elements pointed
1901 * to by the iterators are not equal.
1902 */
1903 template<typename _InputIterator1, typename _InputIterator2>
1904 _GLIBCXX20_CONSTEXPR
1905 inline pair<_InputIterator1, _InputIterator2>
1906 mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1907 _InputIterator2 __first2)
1908 {
1909 // concept requirements
1910 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
1911 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
1912 __glibcxx_function_requires(_EqualOpConcept<
1913 typename iterator_traits<_InputIterator1>::value_type,
1914 typename iterator_traits<_InputIterator2>::value_type>)
1915 __glibcxx_requires_valid_range(__first1, __last1);
1916
1917 return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2,
1918 __gnu_cxx::__ops::__iter_equal_to_iter());
1919 }
1920
1921 /**
1922 * @brief Finds the places in ranges which don't match.
1923 * @ingroup non_mutating_algorithms
1924 * @param __first1 An input iterator.
1925 * @param __last1 An input iterator.
1926 * @param __first2 An input iterator.
1927 * @param __binary_pred A binary predicate @link functors
1928 * functor@endlink.
1929 * @return A pair of iterators pointing to the first mismatch.
1930 *
1931 * This compares the elements of two ranges using the binary_pred
1932 * parameter, and returns a pair
1933 * of iterators. The first iterator points into the first range, the
1934 * second iterator points into the second range, and the elements pointed
1935 * to by the iterators are not equal.
1936 */
1937 template<typename _InputIterator1, typename _InputIterator2,
1938 typename _BinaryPredicate>
1939 _GLIBCXX20_CONSTEXPR
1940 inline pair<_InputIterator1, _InputIterator2>
1941 mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1942 _InputIterator2 __first2, _BinaryPredicate __binary_pred)
1943 {
1944 // concept requirements
1945 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
1946 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
1947 __glibcxx_requires_valid_range(__first1, __last1);
1948
1949 return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2,
1950 __gnu_cxx::__ops::__iter_comp_iter(__binary_pred));
1951 }
1952
1953#if __cplusplus > 201103L
1954
1955 template<typename _InputIterator1, typename _InputIterator2,
1956 typename _BinaryPredicate>
1957 _GLIBCXX20_CONSTEXPR
1958 pair<_InputIterator1, _InputIterator2>
1959 __mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1960 _InputIterator2 __first2, _InputIterator2 __last2,
1961 _BinaryPredicate __binary_pred)
1962 {
1963 while (__first1 != __last1 && __first2 != __last2
1964 && __binary_pred(__first1, __first2))
1965 {
1966 ++__first1;
1967 ++__first2;
1968 }
1969 return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
1970 }
1971
1972 /**
1973 * @brief Finds the places in ranges which don't match.
1974 * @ingroup non_mutating_algorithms
1975 * @param __first1 An input iterator.
1976 * @param __last1 An input iterator.
1977 * @param __first2 An input iterator.
1978 * @param __last2 An input iterator.
1979 * @return A pair of iterators pointing to the first mismatch.
1980 *
1981 * This compares the elements of two ranges using @c == and returns a pair
1982 * of iterators. The first iterator points into the first range, the
1983 * second iterator points into the second range, and the elements pointed
1984 * to by the iterators are not equal.
1985 */
1986 template<typename _InputIterator1, typename _InputIterator2>
1987 _GLIBCXX20_CONSTEXPR
1988 inline pair<_InputIterator1, _InputIterator2>
1989 mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1990 _InputIterator2 __first2, _InputIterator2 __last2)
1991 {
1992 // concept requirements
1993 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
1994 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
1995 __glibcxx_function_requires(_EqualOpConcept<
1996 typename iterator_traits<_InputIterator1>::value_type,
1997 typename iterator_traits<_InputIterator2>::value_type>)
1998 __glibcxx_requires_valid_range(__first1, __last1);
1999 __glibcxx_requires_valid_range(__first2, __last2);
2000
2001 return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2, __last2,
2002 __gnu_cxx::__ops::__iter_equal_to_iter());
2003 }
2004
2005 /**
2006 * @brief Finds the places in ranges which don't match.
2007 * @ingroup non_mutating_algorithms
2008 * @param __first1 An input iterator.
2009 * @param __last1 An input iterator.
2010 * @param __first2 An input iterator.
2011 * @param __last2 An input iterator.
2012 * @param __binary_pred A binary predicate @link functors
2013 * functor@endlink.
2014 * @return A pair of iterators pointing to the first mismatch.
2015 *
2016 * This compares the elements of two ranges using the binary_pred
2017 * parameter, and returns a pair
2018 * of iterators. The first iterator points into the first range, the
2019 * second iterator points into the second range, and the elements pointed
2020 * to by the iterators are not equal.
2021 */
2022 template<typename _InputIterator1, typename _InputIterator2,
2023 typename _BinaryPredicate>
2024 _GLIBCXX20_CONSTEXPR
2025 inline pair<_InputIterator1, _InputIterator2>
2026 mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
2027 _InputIterator2 __first2, _InputIterator2 __last2,
2028 _BinaryPredicate __binary_pred)
2029 {
2030 // concept requirements
2031 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
2032 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
2033 __glibcxx_requires_valid_range(__first1, __last1);
2034 __glibcxx_requires_valid_range(__first2, __last2);
2035
2036 return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2, __last2,
2037 __gnu_cxx::__ops::__iter_comp_iter(__binary_pred));
2038 }
2039#endif
2040
2041_GLIBCXX_END_NAMESPACE_ALGO
2042
2043 /// This is an overload used by find algos for the Input Iterator case.
2044 template<typename _InputIterator, typename _Predicate>
2045 _GLIBCXX20_CONSTEXPR
2046 inline _InputIterator
2047 __find_if(_InputIterator __first, _InputIterator __last,
2048 _Predicate __pred, input_iterator_tag)
2049 {
2050 while (__first != __last && !__pred(__first))
2051 ++__first;
2052 return __first;
2053 }
2054
2055 /// This is an overload used by find algos for the RAI case.
2056 template<typename _RandomAccessIterator, typename _Predicate>
2057 _GLIBCXX20_CONSTEXPR
2058 _RandomAccessIterator
2059 __find_if(_RandomAccessIterator __first, _RandomAccessIterator __last,
2060 _Predicate __pred, random_access_iterator_tag)
2061 {
2062 typename iterator_traits<_RandomAccessIterator>::difference_type
2063 __trip_count = (__last - __first) >> 2;
2064
2065 for (; __trip_count > 0; --__trip_count)
2066 {
2067 if (__pred(__first))
2068 return __first;
2069 ++__first;
2070
2071 if (__pred(__first))
2072 return __first;
2073 ++__first;
2074
2075 if (__pred(__first))
2076 return __first;
2077 ++__first;
2078
2079 if (__pred(__first))
2080 return __first;
2081 ++__first;
2082 }
2083
2084 switch (__last - __first)
2085 {
2086 case 3:
2087 if (__pred(__first))
2088 return __first;
2089 ++__first;
2090 // FALLTHRU
2091 case 2:
2092 if (__pred(__first))
2093 return __first;
2094 ++__first;
2095 // FALLTHRU
2096 case 1:
2097 if (__pred(__first))
2098 return __first;
2099 ++__first;
2100 // FALLTHRU
2101 case 0:
2102 default:
2103 return __last;
2104 }
2105 }
2106
2107 template<typename _Iterator, typename _Predicate>
2108 _GLIBCXX20_CONSTEXPR
2109 inline _Iterator
2110 __find_if(_Iterator __first, _Iterator __last, _Predicate __pred)
2111 {
2112 return __find_if(__first, __last, __pred,
2113 std::__iterator_category(__first));
2114 }
2115
2116 template<typename _InputIterator, typename _Predicate>
2117 _GLIBCXX20_CONSTEXPR
2118 typename iterator_traits<_InputIterator>::difference_type
2119 __count_if(_InputIterator __first, _InputIterator __last, _Predicate __pred)
2120 {
2121 typename iterator_traits<_InputIterator>::difference_type __n = 0;
2122 for (; __first != __last; ++__first)
2123 if (__pred(__first))
2124 ++__n;
2125 return __n;
2126 }
2127
2128 template<typename _ForwardIterator, typename _Predicate>
2129 _GLIBCXX20_CONSTEXPR
2130 _ForwardIterator
2131 __remove_if(_ForwardIterator __first, _ForwardIterator __last,
2132 _Predicate __pred)
2133 {
2134 __first = std::__find_if(__first, __last, __pred);
2135 if (__first == __last)
2136 return __first;
2137 _ForwardIterator __result = __first;
2138 ++__first;
2139 for (; __first != __last; ++__first)
2140 if (!__pred(__first))
2141 {
2142 *__result = _GLIBCXX_MOVE(*__first);
2143 ++__result;
2144 }
2145 return __result;
2146 }
2147
2148#if __cplusplus >= 201103L
2149 template<typename _ForwardIterator1, typename _ForwardIterator2,
2150 typename _BinaryPredicate>
2151 _GLIBCXX20_CONSTEXPR
2152 bool
2153 __is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
2154 _ForwardIterator2 __first2, _BinaryPredicate __pred)
2155 {
2156 // Efficiently compare identical prefixes: O(N) if sequences
2157 // have the same elements in the same order.
2158 for (; __first1 != __last1; ++__first1, (void)++__first2)
2159 if (!__pred(__first1, __first2))
2160 break;
2161
2162 if (__first1 == __last1)
2163 return true;
2164
2165 // Establish __last2 assuming equal ranges by iterating over the
2166 // rest of the list.
2167 _ForwardIterator2 __last2 = __first2;
2168 std::advance(__last2, std::distance(__first1, __last1));
2169 for (_ForwardIterator1 __scan = __first1; __scan != __last1; ++__scan)
2170 {
2171 if (__scan != std::__find_if(__first1, __scan,
2172 __gnu_cxx::__ops::__iter_comp_iter(__pred, __scan)))
2173 continue; // We've seen this one before.
2174
2175 auto __matches
2176 = std::__count_if(__first2, __last2,
2177 __gnu_cxx::__ops::__iter_comp_iter(__pred, __scan));
2178 if (0 == __matches ||
2179 std::__count_if(__scan, __last1,
2180 __gnu_cxx::__ops::__iter_comp_iter(__pred, __scan))
2181 != __matches)
2182 return false;
2183 }
2184 return true;
2185 }
2186
2187 /**
2188 * @brief Checks whether a permutation of the second sequence is equal
2189 * to the first sequence.
2190 * @ingroup non_mutating_algorithms
2191 * @param __first1 Start of first range.
2192 * @param __last1 End of first range.
2193 * @param __first2 Start of second range.
2194 * @return true if there exists a permutation of the elements in the range
2195 * [__first2, __first2 + (__last1 - __first1)), beginning with
2196 * ForwardIterator2 begin, such that equal(__first1, __last1, begin)
2197 * returns true; otherwise, returns false.
2198 */
2199 template<typename _ForwardIterator1, typename _ForwardIterator2>
2200 _GLIBCXX20_CONSTEXPR
2201 inline bool
2202 is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
2203 _ForwardIterator2 __first2)
2204 {
2205 // concept requirements
2206 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
2207 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
2208 __glibcxx_function_requires(_EqualOpConcept<
2209 typename iterator_traits<_ForwardIterator1>::value_type,
2210 typename iterator_traits<_ForwardIterator2>::value_type>)
2211 __glibcxx_requires_valid_range(__first1, __last1);
2212
2213 return std::__is_permutation(__first1, __last1, __first2,
2214 __gnu_cxx::__ops::__iter_equal_to_iter());
2215 }
2216#endif // C++11
2217
2218_GLIBCXX_END_NAMESPACE_VERSION
2219} // namespace std
2220
2221// NB: This file is included within many other C++ includes, as a way
2222// of getting the base algorithms. So, make sure that parallel bits
2223// come in too if requested.
2224#ifdef _GLIBCXX_PARALLEL
2225# include <parallel/algobase.h>
2226#endif
2227
2228#endif
algobase.h
Parallel STL function calls corresponding to the stl_algobase.h header. The functions defined here ma...
std::is_constant_evaluated
constexpr bool is_constant_evaluated() noexcept
Returns true only when called during constant evaluation.
Definition: type_traits:3520
std::move
constexpr std::remove_reference< _Tp >::type && move(_Tp &&__t) noexcept
Convert a value to an rvalue.
Definition: move.h:104
std::swap
void swap(any &__x, any &__y) noexcept
Exchange the states of two any objects.
Definition: any:429
std::move_backward
constexpr _BI2 move_backward(_BI1 __first, _BI1 __last, _BI2 __result)
Moves the range [first,last) into result.
Definition: stl_algobase.h:883
std::max
constexpr const _Tp & max(const _Tp &, const _Tp &)
This does what you think it does.
Definition: stl_algobase.h:254
std::min
constexpr const _Tp & min(const _Tp &, const _Tp &)
This does what you think it does.
Definition: stl_algobase.h:230
std::__iterator_category
constexpr iterator_traits< _Iter >::iterator_category __iterator_category(const _Iter &)
Definition: stl_iterator_base_types.h:238
std
ISO C++ entities toplevel namespace is std.
std::distance
constexpr iterator_traits< _InputIterator >::difference_type distance(_InputIterator __first, _InputIterator __last)
A generalization of pointer arithmetic.
Definition: stl_iterator_base_funcs.h:147
std::__find_if
constexpr _InputIterator __find_if(_InputIterator __first, _InputIterator __last, _Predicate __pred, input_iterator_tag)
This is an overload used by find algos for the Input Iterator case.
Definition: stl_algobase.h:2047
std::__lg
constexpr int __lg(int __n)
This is a helper function for the sort routines and for random.tcc.
Definition: stl_algobase.h:1505
std::advance
constexpr void advance(_InputIterator &__i, _Distance __n)
A generalization of pointer arithmetic.
Definition: stl_iterator_base_funcs.h:218
std::is_nothrow_copy_constructible
is_nothrow_copy_constructible
Definition: type_traits:1081
__gnu_debug::_Safe_iterator
Safe iterator wrapper.
Definition: safe_iterator.h:117
std::iterator_traits
Traits class for iterators.
Definition: stl_iterator_base_types.h:178
std::input_iterator_tag
Marking input iterators.
Definition: stl_iterator_base_types.h:93
std::output_iterator_tag
Marking output iterators.
Definition: stl_iterator_base_types.h:96
std::random_access_iterator_tag
Random-access iterators support a superset of bidirectional iterator operations.
Definition: stl_iterator_base_types.h:107