1// Core algorithmic facilities -*- C++ -*-
2
3// Copyright (C) 2001-2021 Free Software Foundation, Inc.
4//
5// This file is part of the GNU ISO C++ Library. This library is free
6// software; you can redistribute it and/or modify it under the
7// terms of the GNU General Public License as published by the
8// Free Software Foundation; either version 3, or (at your option)
9// any later version.
10
11// This library is distributed in the hope that it will be useful,
12// but WITHOUT ANY WARRANTY; without even the implied warranty of
13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14// GNU General Public License for more details.
15
16// Under Section 7 of GPL version 3, you are granted additional
17// permissions described in the GCC Runtime Library Exception, version
18// 3.1, as published by the Free Software Foundation.
19
20// You should have received a copy of the GNU General Public License and
21// a copy of the GCC Runtime Library Exception along with this program;
22// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23// <http://www.gnu.org/licenses/>.
24
25/*
26 *
27 * Copyright (c) 1994
28 * Hewlett-Packard Company
29 *
30 * Permission to use, copy, modify, distribute and sell this software
31 * and its documentation for any purpose is hereby granted without fee,
32 * provided that the above copyright notice appear in all copies and
33 * that both that copyright notice and this permission notice appear
34 * in supporting documentation. Hewlett-Packard Company makes no
35 * representations about the suitability of this software for any
36 * purpose. It is provided "as is" without express or implied warranty.
37 *
38 *
39 * Copyright (c) 1996-1998
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<_IsMove,
424 is_move_assignable<_Tp>,
425 is_copy_assignable<_Tp>>;
426 // trivial types can have deleted assignment
427 static_assert( __assignable::type::value, "type is not 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>::value_type>)
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<_IsMove,
735 is_move_assignable<_Tp>,
736 is_copy_assignable<_Tp>>;
737 // trivial types can have deleted assignment
738 static_assert( __assignable::type::value, "type is not 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(_ConvertibleConcept<
854 typename iterator_traits<_BI1>::value_type,
855 typename iterator_traits<_BI2>::value_type>)
856 __glibcxx_requires_can_decrement_range(__first, __last, __result);
857
858 return std::__copy_move_backward_a<__is_move_iterator<_BI1>::__value>
859 (std::__miter_base(__first), std::__miter_base(__last), __result);
860 }
861
862#if __cplusplus >= 201103L
863 /**
864 * @brief Moves the range [first,last) into result.
865 * @ingroup mutating_algorithms
866 * @param __first A bidirectional iterator.
867 * @param __last A bidirectional iterator.
868 * @param __result A bidirectional iterator.
869 * @return result - (last - first)
870 *
871 * The function has the same effect as move, but starts at the end of the
872 * range and works its way to the start, returning the start of the result.
873 * This inline function will boil down to a call to @c memmove whenever
874 * possible. Failing that, if random access iterators are passed, then the
875 * loop count will be known (and therefore a candidate for compiler
876 * optimizations such as unrolling).
877 *
878 * Result may not be in the range (first,last]. Use move instead. Note
879 * that the start of the output range may overlap [first,last).
880 */
881 template<typename _BI1, typename _BI2>
882 _GLIBCXX20_CONSTEXPR
883 inline _BI2
884 move_backward(_BI1 __first, _BI1 __last, _BI2 __result)
885 {
886 // concept requirements
887 __glibcxx_function_requires(_BidirectionalIteratorConcept<_BI1>)
888 __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<_BI2>)
889 __glibcxx_function_requires(_ConvertibleConcept<
890 typename iterator_traits<_BI1>::value_type,
891 typename iterator_traits<_BI2>::value_type>)
892 __glibcxx_requires_can_decrement_range(__first, __last, __result);
893
894 return std::__copy_move_backward_a<true>(std::__miter_base(__first),
895 std::__miter_base(__last),
896 __result);
897 }
898
899#define _GLIBCXX_MOVE_BACKWARD3(_Tp, _Up, _Vp) std::move_backward(_Tp, _Up, _Vp)
900#else
901#define _GLIBCXX_MOVE_BACKWARD3(_Tp, _Up, _Vp) std::copy_backward(_Tp, _Up, _Vp)
902#endif
903
904 template<typename _ForwardIterator, typename _Tp>
905 _GLIBCXX20_CONSTEXPR
906 inline typename
907 __gnu_cxx::__enable_if<!__is_scalar<_Tp>::__value, void>::__type
908 __fill_a1(_ForwardIterator __first, _ForwardIterator __last,
909 const _Tp& __value)
910 {
911 for (; __first != __last; ++__first)
912 *__first = __value;
913 }
914
915 template<typename _ForwardIterator, typename _Tp>
916 _GLIBCXX20_CONSTEXPR
917 inline typename
918 __gnu_cxx::__enable_if<__is_scalar<_Tp>::__value, void>::__type
919 __fill_a1(_ForwardIterator __first, _ForwardIterator __last,
920 const _Tp& __value)
921 {
922 const _Tp __tmp = __value;
923 for (; __first != __last; ++__first)
924 *__first = __tmp;
925 }
926
927 // Specialization: for char types we can use memset.
928 template<typename _Tp>
929 _GLIBCXX20_CONSTEXPR
930 inline typename
931 __gnu_cxx::__enable_if<__is_byte<_Tp>::__value, void>::__type
932 __fill_a1(_Tp* __first, _Tp* __last, const _Tp& __c)
933 {
934 const _Tp __tmp = __c;
935#if __cpp_lib_is_constant_evaluated
936 if (std::is_constant_evaluated())
937 {
938 for (; __first != __last; ++__first)
939 *__first = __tmp;
940 return;
941 }
942#endif
943 if (const size_t __len = __last - __first)
944 __builtin_memset(__first, static_cast<unsigned char>(__tmp), __len);
945 }
946
947 template<typename _Ite, typename _Cont, typename _Tp>
948 _GLIBCXX20_CONSTEXPR
949 inline void
950 __fill_a1(::__gnu_cxx::__normal_iterator<_Ite, _Cont> __first,
951 ::__gnu_cxx::__normal_iterator<_Ite, _Cont> __last,
952 const _Tp& __value)
953 { std::__fill_a1(__first.base(), __last.base(), __value); }
954
955 template<typename _Tp, typename _VTp>
956 void
957 __fill_a1(const _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*>&,
958 const _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*>&,
959 const _VTp&);
960
961 void
962 __fill_a1(_GLIBCXX_STD_C::_Bit_iterator, _GLIBCXX_STD_C::_Bit_iterator,
963 const bool&);
964
965 template<typename _FIte, typename _Tp>
966 _GLIBCXX20_CONSTEXPR
967 inline void
968 __fill_a(_FIte __first, _FIte __last, const _Tp& __value)
969 { std::__fill_a1(__first, __last, __value); }
970
971 template<typename _Ite, typename _Seq, typename _Cat, typename _Tp>
972 void
973 __fill_a(const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
974 const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
975 const _Tp&);
976
977 /**
978 * @brief Fills the range [first,last) with copies of value.
979 * @ingroup mutating_algorithms
980 * @param __first A forward iterator.
981 * @param __last A forward iterator.
982 * @param __value A reference-to-const of arbitrary type.
983 * @return Nothing.
984 *
985 * This function fills a range with copies of the same value. For char
986 * types filling contiguous areas of memory, this becomes an inline call
987 * to @c memset or @c wmemset.
988 */
989 template<typename _ForwardIterator, typename _Tp>
990 _GLIBCXX20_CONSTEXPR
991 inline void
992 fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value)
993 {
994 // concept requirements
995 __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
996 _ForwardIterator>)
997 __glibcxx_requires_valid_range(__first, __last);
998
999 std::__fill_a(__first, __last, __value);
1000 }
1001
1002 // Used by fill_n, generate_n, etc. to convert _Size to an integral type:
1003 inline _GLIBCXX_CONSTEXPR int
1004 __size_to_integer(int __n) { return __n; }
1005 inline _GLIBCXX_CONSTEXPR unsigned
1006 __size_to_integer(unsigned __n) { return __n; }
1007 inline _GLIBCXX_CONSTEXPR long
1008 __size_to_integer(long __n) { return __n; }
1009 inline _GLIBCXX_CONSTEXPR unsigned long
1010 __size_to_integer(unsigned long __n) { return __n; }
1011 inline _GLIBCXX_CONSTEXPR long long
1012 __size_to_integer(long long __n) { return __n; }
1013 inline _GLIBCXX_CONSTEXPR unsigned long long
1014 __size_to_integer(unsigned long long __n) { return __n; }
1015
1016#if defined(__GLIBCXX_TYPE_INT_N_0)
1017 inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_0
1018 __size_to_integer(__GLIBCXX_TYPE_INT_N_0 __n) { return __n; }
1019 inline _GLIBCXX_CONSTEXPR unsigned __GLIBCXX_TYPE_INT_N_0
1020 __size_to_integer(unsigned __GLIBCXX_TYPE_INT_N_0 __n) { return __n; }
1021#endif
1022#if defined(__GLIBCXX_TYPE_INT_N_1)
1023 inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_1
1024 __size_to_integer(__GLIBCXX_TYPE_INT_N_1 __n) { return __n; }
1025 inline _GLIBCXX_CONSTEXPR unsigned __GLIBCXX_TYPE_INT_N_1
1026 __size_to_integer(unsigned __GLIBCXX_TYPE_INT_N_1 __n) { return __n; }
1027#endif
1028#if defined(__GLIBCXX_TYPE_INT_N_2)
1029 inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_2
1030 __size_to_integer(__GLIBCXX_TYPE_INT_N_2 __n) { return __n; }
1031 inline _GLIBCXX_CONSTEXPR unsigned __GLIBCXX_TYPE_INT_N_2
1032 __size_to_integer(unsigned __GLIBCXX_TYPE_INT_N_2 __n) { return __n; }
1033#endif
1034#if defined(__GLIBCXX_TYPE_INT_N_3)
1035 inline _GLIBCXX_CONSTEXPR unsigned __GLIBCXX_TYPE_INT_N_3
1036 __size_to_integer(__GLIBCXX_TYPE_INT_N_3 __n) { return __n; }
1037 inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_3
1038 __size_to_integer(unsigned __GLIBCXX_TYPE_INT_N_3 __n) { return __n; }
1039#endif
1040
1041 inline _GLIBCXX_CONSTEXPR long long
1042 __size_to_integer(float __n) { return (long long)__n; }
1043 inline _GLIBCXX_CONSTEXPR long long
1044 __size_to_integer(double __n) { return (long long)__n; }
1045 inline _GLIBCXX_CONSTEXPR long long
1046 __size_to_integer(long double __n) { return (long long)__n; }
1047#if !defined(__STRICT_ANSI__) && defined(_GLIBCXX_USE_FLOAT128) && !defined(__CUDACC__)
1048 inline _GLIBCXX_CONSTEXPR long long
1049 __size_to_integer(__float128 __n) { return (long long)__n; }
1050#endif
1051
1052 template<typename _OutputIterator, typename _Size, typename _Tp>
1053 _GLIBCXX20_CONSTEXPR
1054 inline typename
1055 __gnu_cxx::__enable_if<!__is_scalar<_Tp>::__value, _OutputIterator>::__type
1056 __fill_n_a1(_OutputIterator __first, _Size __n, const _Tp& __value)
1057 {
1058 for (; __n > 0; --__n, (void) ++__first)
1059 *__first = __value;
1060 return __first;
1061 }
1062
1063 template<typename _OutputIterator, typename _Size, typename _Tp>
1064 _GLIBCXX20_CONSTEXPR
1065 inline typename
1066 __gnu_cxx::__enable_if<__is_scalar<_Tp>::__value, _OutputIterator>::__type
1067 __fill_n_a1(_OutputIterator __first, _Size __n, const _Tp& __value)
1068 {
1069 const _Tp __tmp = __value;
1070 for (; __n > 0; --__n, (void) ++__first)
1071 *__first = __tmp;
1072 return __first;
1073 }
1074
1075 template<typename _Ite, typename _Seq, typename _Cat, typename _Size,
1076 typename _Tp>
1077 ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>
1078 __fill_n_a(const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>& __first,
1079 _Size __n, const _Tp& __value,
1080 std::input_iterator_tag);
1081
1082 template<typename _OutputIterator, typename _Size, typename _Tp>
1083 _GLIBCXX20_CONSTEXPR
1084 inline _OutputIterator
1085 __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value,
1086 std::output_iterator_tag)
1087 {
1088#if __cplusplus >= 201103L
1089 static_assert(is_integral<_Size>{}, "fill_n must pass integral size");
1090#endif
1091 return __fill_n_a1(__first, __n, __value);
1092 }
1093
1094 template<typename _OutputIterator, typename _Size, typename _Tp>
1095 _GLIBCXX20_CONSTEXPR
1096 inline _OutputIterator
1097 __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value,
1098 std::input_iterator_tag)
1099 {
1100#if __cplusplus >= 201103L
1101 static_assert(is_integral<_Size>{}, "fill_n must pass integral size");
1102#endif
1103 return __fill_n_a1(__first, __n, __value);
1104 }
1105
1106 template<typename _OutputIterator, typename _Size, typename _Tp>
1107 _GLIBCXX20_CONSTEXPR
1108 inline _OutputIterator
1109 __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value,
1110 std::random_access_iterator_tag)
1111 {
1112#if __cplusplus >= 201103L
1113 static_assert(is_integral<_Size>{}, "fill_n must pass integral size");
1114#endif
1115 if (__n <= 0)
1116 return __first;
1117
1118 __glibcxx_requires_can_increment(__first, __n);
1119
1120 std::__fill_a(__first, __first + __n, __value);
1121 return __first + __n;
1122 }
1123
1124 /**
1125 * @brief Fills the range [first,first+n) with copies of value.
1126 * @ingroup mutating_algorithms
1127 * @param __first An output iterator.
1128 * @param __n The count of copies to perform.
1129 * @param __value A reference-to-const of arbitrary type.
1130 * @return The iterator at first+n.
1131 *
1132 * This function fills a range with copies of the same value. For char
1133 * types filling contiguous areas of memory, this becomes an inline call
1134 * to @c memset or @c wmemset.
1135 *
1136 * If @p __n is negative, the function does nothing.
1137 */
1138 // _GLIBCXX_RESOLVE_LIB_DEFECTS
1139 // DR 865. More algorithms that throw away information
1140 // DR 426. search_n(), fill_n(), and generate_n() with negative n
1141 template<typename _OI, typename _Size, typename _Tp>
1142 _GLIBCXX20_CONSTEXPR
1143 inline _OI
1144 fill_n(_OI __first, _Size __n, const _Tp& __value)
1145 {
1146 // concept requirements
1147 __glibcxx_function_requires(_OutputIteratorConcept<_OI, _Tp>)
1148
1149 return std::__fill_n_a(__first, std::__size_to_integer(__n), __value,
1150 std::__iterator_category(__first));
1151 }
1152
1153 template<bool _BoolType>
1154 struct __equal
1155 {
1156 template<typename _II1, typename _II2>
1157 _GLIBCXX20_CONSTEXPR
1158 static bool
1159 equal(_II1 __first1, _II1 __last1, _II2 __first2)
1160 {
1161 for (; __first1 != __last1; ++__first1, (void) ++__first2)
1162 if (!(*__first1 == *__first2))
1163 return false;
1164 return true;
1165 }
1166 };
1167
1168 template<>
1169 struct __equal<true>
1170 {
1171 template<typename _Tp>
1172 _GLIBCXX20_CONSTEXPR
1173 static bool
1174 equal(const _Tp* __first1, const _Tp* __last1, const _Tp* __first2)
1175 {
1176 if (const size_t __len = (__last1 - __first1))
1177 return !std::__memcmp(__first1, __first2, __len);
1178 return true;
1179 }
1180 };
1181
1182 template<typename _Tp, typename _Ref, typename _Ptr, typename _II>
1183 typename __gnu_cxx::__enable_if<
1184 __is_random_access_iter<_II>::__value, bool>::__type
1185 __equal_aux1(_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
1186 _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
1187 _II);
1188
1189 template<typename _Tp1, typename _Ref1, typename _Ptr1,
1190 typename _Tp2, typename _Ref2, typename _Ptr2>
1191 bool
1192 __equal_aux1(_GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
1193 _GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
1194 _GLIBCXX_STD_C::_Deque_iterator<_Tp2, _Ref2, _Ptr2>);
1195
1196 template<typename _II, typename _Tp, typename _Ref, typename _Ptr>
1197 typename __gnu_cxx::__enable_if<
1198 __is_random_access_iter<_II>::__value, bool>::__type
1199 __equal_aux1(_II, _II,
1200 _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>);
1201
1202 template<typename _II1, typename _II2>
1203 _GLIBCXX20_CONSTEXPR
1204 inline bool
1205 __equal_aux1(_II1 __first1, _II1 __last1, _II2 __first2)
1206 {
1207 typedef typename iterator_traits<_II1>::value_type _ValueType1;
1208 const bool __simple = ((__is_integer<_ValueType1>::__value
1209 || __is_pointer<_ValueType1>::__value)
1210 && __memcmpable<_II1, _II2>::__value);
1211 return std::__equal<__simple>::equal(__first1, __last1, __first2);
1212 }
1213
1214 template<typename _II1, typename _II2>
1215 _GLIBCXX20_CONSTEXPR
1216 inline bool
1217 __equal_aux(_II1 __first1, _II1 __last1, _II2 __first2)
1218 {
1219 return std::__equal_aux1(std::__niter_base(__first1),
1220 std::__niter_base(__last1),
1221 std::__niter_base(__first2));
1222 }
1223
1224 template<typename _II1, typename _Seq1, typename _Cat1, typename _II2>
1225 bool
1226 __equal_aux(const ::__gnu_debug::_Safe_iterator<_II1, _Seq1, _Cat1>&,
1227 const ::__gnu_debug::_Safe_iterator<_II1, _Seq1, _Cat1>&,
1228 _II2);
1229
1230 template<typename _II1, typename _II2, typename _Seq2, typename _Cat2>
1231 bool
1232 __equal_aux(_II1, _II1,
1233 const ::__gnu_debug::_Safe_iterator<_II2, _Seq2, _Cat2>&);
1234
1235 template<typename _II1, typename _Seq1, typename _Cat1,
1236 typename _II2, typename _Seq2, typename _Cat2>
1237 bool
1238 __equal_aux(const ::__gnu_debug::_Safe_iterator<_II1, _Seq1, _Cat1>&,
1239 const ::__gnu_debug::_Safe_iterator<_II1, _Seq1, _Cat1>&,
1240 const ::__gnu_debug::_Safe_iterator<_II2, _Seq2, _Cat2>&);
1241
1242 template<typename, typename>
1243 struct __lc_rai
1244 {
1245 template<typename _II1, typename _II2>
1246 _GLIBCXX20_CONSTEXPR
1247 static _II1
1248 __newlast1(_II1, _II1 __last1, _II2, _II2)
1249 { return __last1; }
1250
1251 template<typename _II>
1252 _GLIBCXX20_CONSTEXPR
1253 static bool
1254 __cnd2(_II __first, _II __last)
1255 { return __first != __last; }
1256 };
1257
1258 template<>
1259 struct __lc_rai<random_access_iterator_tag, random_access_iterator_tag>
1260 {
1261 template<typename _RAI1, typename _RAI2>
1262 _GLIBCXX20_CONSTEXPR
1263 static _RAI1
1264 __newlast1(_RAI1 __first1, _RAI1 __last1,
1265 _RAI2 __first2, _RAI2 __last2)
1266 {
1267 const typename iterator_traits<_RAI1>::difference_type
1268 __diff1 = __last1 - __first1;
1269 const typename iterator_traits<_RAI2>::difference_type
1270 __diff2 = __last2 - __first2;
1271 return __diff2 < __diff1 ? __first1 + __diff2 : __last1;
1272 }
1273
1274 template<typename _RAI>
1275 static _GLIBCXX20_CONSTEXPR bool
1276 __cnd2(_RAI, _RAI)
1277 { return true; }
1278 };
1279
1280 template<typename _II1, typename _II2, typename _Compare>
1281 _GLIBCXX20_CONSTEXPR
1282 bool
1283 __lexicographical_compare_impl(_II1 __first1, _II1 __last1,
1284 _II2 __first2, _II2 __last2,
1285 _Compare __comp)
1286 {
1287 typedef typename iterator_traits<_II1>::iterator_category _Category1;
1288 typedef typename iterator_traits<_II2>::iterator_category _Category2;
1289 typedef std::__lc_rai<_Category1, _Category2> __rai_type;
1290
1291 __last1 = __rai_type::__newlast1(__first1, __last1, __first2, __last2);
1292 for (; __first1 != __last1 && __rai_type::__cnd2(__first2, __last2);
1293 ++__first1, (void)++__first2)
1294 {
1295 if (__comp(__first1, __first2))
1296 return true;
1297 if (__comp(__first2, __first1))
1298 return false;
1299 }
1300 return __first1 == __last1 && __first2 != __last2;
1301 }
1302
1303 template<bool _BoolType>
1304 struct __lexicographical_compare
1305 {
1306 template<typename _II1, typename _II2>
1307 _GLIBCXX20_CONSTEXPR
1308 static bool
1309 __lc(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
1310 {
1311 using __gnu_cxx::__ops::__iter_less_iter;
1312 return std::__lexicographical_compare_impl(__first1, __last1,
1313 __first2, __last2,
1314 __iter_less_iter());
1315 }
1316
1317 template<typename _II1, typename _II2>
1318 _GLIBCXX20_CONSTEXPR
1319 static int
1320 __3way(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
1321 {
1322 while (__first1 != __last1)
1323 {
1324 if (__first2 == __last2)
1325 return +1;
1326 if (*__first1 < *__first2)
1327 return -1;
1328 if (*__first2 < *__first1)
1329 return +1;
1330 ++__first1;
1331 ++__first2;
1332 }
1333 return int(__first2 == __last2) - 1;
1334 }
1335 };
1336
1337 template<>
1338 struct __lexicographical_compare<true>
1339 {
1340 template<typename _Tp, typename _Up>
1341 _GLIBCXX20_CONSTEXPR
1342 static bool
1343 __lc(const _Tp* __first1, const _Tp* __last1,
1344 const _Up* __first2, const _Up* __last2)
1345 { return __3way(__first1, __last1, __first2, __last2) < 0; }
1346
1347 template<typename _Tp, typename _Up>
1348 _GLIBCXX20_CONSTEXPR
1349 static ptrdiff_t
1350 __3way(const _Tp* __first1, const _Tp* __last1,
1351 const _Up* __first2, const _Up* __last2)
1352 {
1353 const size_t __len1 = __last1 - __first1;
1354 const size_t __len2 = __last2 - __first2;
1355 if (const size_t __len = std::min(__len1, __len2))
1356 if (int __result = std::__memcmp(__first1, __first2, __len))
1357 return __result;
1358 return ptrdiff_t(__len1 - __len2);
1359 }
1360 };
1361
1362 template<typename _II1, typename _II2>
1363 _GLIBCXX20_CONSTEXPR
1364 inline bool
1365 __lexicographical_compare_aux1(_II1 __first1, _II1 __last1,
1366 _II2 __first2, _II2 __last2)
1367 {
1368 typedef typename iterator_traits<_II1>::value_type _ValueType1;
1369 typedef typename iterator_traits<_II2>::value_type _ValueType2;
1370 const bool __simple =
1371 (__is_memcmp_ordered_with<_ValueType1, _ValueType2>::__value
1372 && __is_pointer<_II1>::__value
1373 && __is_pointer<_II2>::__value
1374#if __cplusplus > 201703L && __cpp_lib_concepts
1375 // For C++20 iterator_traits<volatile T*>::value_type is non-volatile
1376 // so __is_byte<T> could be true, but we can't use memcmp with
1377 // volatile data.
1378 && !is_volatile_v<remove_reference_t<iter_reference_t<_II1>>>
1379 && !is_volatile_v<remove_reference_t<iter_reference_t<_II2>>>
1380#endif
1381 );
1382
1383 return std::__lexicographical_compare<__simple>::__lc(__first1, __last1,
1384 __first2, __last2);
1385 }
1386
1387 template<typename _Tp1, typename _Ref1, typename _Ptr1,
1388 typename _Tp2>
1389 bool
1390 __lexicographical_compare_aux1(
1391 _GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
1392 _GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
1393 _Tp2*, _Tp2*);
1394
1395 template<typename _Tp1,
1396 typename _Tp2, typename _Ref2, typename _Ptr2>
1397 bool
1398 __lexicographical_compare_aux1(_Tp1*, _Tp1*,
1399 _GLIBCXX_STD_C::_Deque_iterator<_Tp2, _Ref2, _Ptr2>,
1400 _GLIBCXX_STD_C::_Deque_iterator<_Tp2, _Ref2, _Ptr2>);
1401
1402 template<typename _Tp1, typename _Ref1, typename _Ptr1,
1403 typename _Tp2, typename _Ref2, typename _Ptr2>
1404 bool
1405 __lexicographical_compare_aux1(
1406 _GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
1407 _GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
1408 _GLIBCXX_STD_C::_Deque_iterator<_Tp2, _Ref2, _Ptr2>,
1409 _GLIBCXX_STD_C::_Deque_iterator<_Tp2, _Ref2, _Ptr2>);
1410
1411 template<typename _II1, typename _II2>
1412 _GLIBCXX20_CONSTEXPR
1413 inline bool
1414 __lexicographical_compare_aux(_II1 __first1, _II1 __last1,
1415 _II2 __first2, _II2 __last2)
1416 {
1417 return std::__lexicographical_compare_aux1(std::__niter_base(__first1),
1418 std::__niter_base(__last1),
1419 std::__niter_base(__first2),
1420 std::__niter_base(__last2));
1421 }
1422
1423 template<typename _Iter1, typename _Seq1, typename _Cat1,
1424 typename _II2>
1425 bool
1426 __lexicographical_compare_aux(
1427 const ::__gnu_debug::_Safe_iterator<_Iter1, _Seq1, _Cat1>&,
1428 const ::__gnu_debug::_Safe_iterator<_Iter1, _Seq1, _Cat1>&,
1429 _II2, _II2);
1430
1431 template<typename _II1,
1432 typename _Iter2, typename _Seq2, typename _Cat2>
1433 bool
1434 __lexicographical_compare_aux(
1435 _II1, _II1,
1436 const ::__gnu_debug::_Safe_iterator<_Iter2, _Seq2, _Cat2>&,
1437 const ::__gnu_debug::_Safe_iterator<_Iter2, _Seq2, _Cat2>&);
1438
1439 template<typename _Iter1, typename _Seq1, typename _Cat1,
1440 typename _Iter2, typename _Seq2, typename _Cat2>
1441 bool
1442 __lexicographical_compare_aux(
1443 const ::__gnu_debug::_Safe_iterator<_Iter1, _Seq1, _Cat1>&,
1444 const ::__gnu_debug::_Safe_iterator<_Iter1, _Seq1, _Cat1>&,
1445 const ::__gnu_debug::_Safe_iterator<_Iter2, _Seq2, _Cat2>&,
1446 const ::__gnu_debug::_Safe_iterator<_Iter2, _Seq2, _Cat2>&);
1447
1448 template<typename _ForwardIterator, typename _Tp, typename _Compare>
1449 _GLIBCXX20_CONSTEXPR
1450 _ForwardIterator
1451 __lower_bound(_ForwardIterator __first, _ForwardIterator __last,
1452 const _Tp& __val, _Compare __comp)
1453 {
1454 typedef typename iterator_traits<_ForwardIterator>::difference_type
1455 _DistanceType;
1456
1457 _DistanceType __len = std::distance(__first, __last);
1458
1459 while (__len > 0)
1460 {
1461 _DistanceType __half = __len >> 1;
1462 _ForwardIterator __middle = __first;
1463 std::advance(__middle, __half);
1464 if (__comp(__middle, __val))
1465 {
1466 __first = __middle;
1467 ++__first;
1468 __len = __len - __half - 1;
1469 }
1470 else
1471 __len = __half;
1472 }
1473 return __first;
1474 }
1475
1476 /**
1477 * @brief Finds the first position in which @a val could be inserted
1478 * without changing the ordering.
1479 * @param __first An iterator.
1480 * @param __last Another iterator.
1481 * @param __val The search term.
1482 * @return An iterator pointing to the first element <em>not less
1483 * than</em> @a val, or end() if every element is less than
1484 * @a val.
1485 * @ingroup binary_search_algorithms
1486 */
1487 template<typename _ForwardIterator, typename _Tp>
1488 _GLIBCXX20_CONSTEXPR
1489 inline _ForwardIterator
1490 lower_bound(_ForwardIterator __first, _ForwardIterator __last,
1491 const _Tp& __val)
1492 {
1493 // concept requirements
1494 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
1495 __glibcxx_function_requires(_LessThanOpConcept<
1496 typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
1497 __glibcxx_requires_partitioned_lower(__first, __last, __val);
1498
1499 return std::__lower_bound(__first, __last, __val,
1500 __gnu_cxx::__ops::__iter_less_val());
1501 }
1502
1503 /// This is a helper function for the sort routines and for random.tcc.
1504 // Precondition: __n > 0.
1505 inline _GLIBCXX_CONSTEXPR int
1506 __lg(int __n)
1507 { return (int)sizeof(int) * __CHAR_BIT__ - 1 - __builtin_clz(__n); }
1508
1509 inline _GLIBCXX_CONSTEXPR unsigned
1510 __lg(unsigned __n)
1511 { return (int)sizeof(int) * __CHAR_BIT__ - 1 - __builtin_clz(__n); }
1512
1513 inline _GLIBCXX_CONSTEXPR long
1514 __lg(long __n)
1515 { return (int)sizeof(long) * __CHAR_BIT__ - 1 - __builtin_clzl(__n); }
1516
1517 inline _GLIBCXX_CONSTEXPR unsigned long
1518 __lg(unsigned long __n)
1519 { return (int)sizeof(long) * __CHAR_BIT__ - 1 - __builtin_clzl(__n); }
1520
1521 inline _GLIBCXX_CONSTEXPR long long
1522 __lg(long long __n)
1523 { return (int)sizeof(long long) * __CHAR_BIT__ - 1 - __builtin_clzll(__n); }
1524
1525 inline _GLIBCXX_CONSTEXPR unsigned long long
1526 __lg(unsigned long long __n)
1527 { return (int)sizeof(long long) * __CHAR_BIT__ - 1 - __builtin_clzll(__n); }
1528
1529_GLIBCXX_BEGIN_NAMESPACE_ALGO
1530
1531 /**
1532 * @brief Tests a range for element-wise equality.
1533 * @ingroup non_mutating_algorithms
1534 * @param __first1 An input iterator.
1535 * @param __last1 An input iterator.
1536 * @param __first2 An input iterator.
1537 * @return A boolean true or false.
1538 *
1539 * This compares the elements of two ranges using @c == and returns true or
1540 * false depending on whether all of the corresponding elements of the
1541 * ranges are equal.
1542 */
1543 template<typename _II1, typename _II2>
1544 _GLIBCXX20_CONSTEXPR
1545 inline bool
1546 equal(_II1 __first1, _II1 __last1, _II2 __first2)
1547 {
1548 // concept requirements
1549 __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1550 __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1551 __glibcxx_function_requires(_EqualOpConcept<
1552 typename iterator_traits<_II1>::value_type,
1553 typename iterator_traits<_II2>::value_type>)
1554 __glibcxx_requires_can_increment_range(__first1, __last1, __first2);
1555
1556 return std::__equal_aux(__first1, __last1, __first2);
1557 }
1558
1559 /**
1560 * @brief Tests a range for element-wise equality.
1561 * @ingroup non_mutating_algorithms
1562 * @param __first1 An input iterator.
1563 * @param __last1 An input iterator.
1564 * @param __first2 An input iterator.
1565 * @param __binary_pred A binary predicate @link functors
1566 * functor@endlink.
1567 * @return A boolean true or false.
1568 *
1569 * This compares the elements of two ranges using the binary_pred
1570 * parameter, and returns true or
1571 * false depending on whether all of the corresponding elements of the
1572 * ranges are equal.
1573 */
1574 template<typename _IIter1, typename _IIter2, typename _BinaryPredicate>
1575 _GLIBCXX20_CONSTEXPR
1576 inline bool
1577 equal(_IIter1 __first1, _IIter1 __last1,
1578 _IIter2 __first2, _BinaryPredicate __binary_pred)
1579 {
1580 // concept requirements
1581 __glibcxx_function_requires(_InputIteratorConcept<_IIter1>)
1582 __glibcxx_function_requires(_InputIteratorConcept<_IIter2>)
1583 __glibcxx_requires_valid_range(__first1, __last1);
1584
1585 for (; __first1 != __last1; ++__first1, (void)++__first2)
1586 if (!bool(__binary_pred(*__first1, *__first2)))
1587 return false;
1588 return true;
1589 }
1590
1591#if __cplusplus >= 201103L
1592 // 4-iterator version of std::equal<It1, It2> for use in C++11.
1593 template<typename _II1, typename _II2>
1594 _GLIBCXX20_CONSTEXPR
1595 inline bool
1596 __equal4(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
1597 {
1598 using _RATag = random_access_iterator_tag;
1599 using _Cat1 = typename iterator_traits<_II1>::iterator_category;
1600 using _Cat2 = typename iterator_traits<_II2>::iterator_category;
1601 using _RAIters = __and_<is_same<_Cat1, _RATag>, is_same<_Cat2, _RATag>>;
1602 if (_RAIters())
1603 {
1604 auto __d1 = std::distance(__first1, __last1);
1605 auto __d2 = std::distance(__first2, __last2);
1606 if (__d1 != __d2)
1607 return false;
1608 return _GLIBCXX_STD_A::equal(__first1, __last1, __first2);
1609 }
1610
1611 for (; __first1 != __last1 && __first2 != __last2;
1612 ++__first1, (void)++__first2)
1613 if (!(*__first1 == *__first2))
1614 return false;
1615 return __first1 == __last1 && __first2 == __last2;
1616 }
1617
1618 // 4-iterator version of std::equal<It1, It2, BinaryPred> for use in C++11.
1619 template<typename _II1, typename _II2, typename _BinaryPredicate>
1620 _GLIBCXX20_CONSTEXPR
1621 inline bool
1622 __equal4(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2,
1623 _BinaryPredicate __binary_pred)
1624 {
1625 using _RATag = random_access_iterator_tag;
1626 using _Cat1 = typename iterator_traits<_II1>::iterator_category;
1627 using _Cat2 = typename iterator_traits<_II2>::iterator_category;
1628 using _RAIters = __and_<is_same<_Cat1, _RATag>, is_same<_Cat2, _RATag>>;
1629 if (_RAIters())
1630 {
1631 auto __d1 = std::distance(__first1, __last1);
1632 auto __d2 = std::distance(__first2, __last2);
1633 if (__d1 != __d2)
1634 return false;
1635 return _GLIBCXX_STD_A::equal(__first1, __last1, __first2,
1636 __binary_pred);
1637 }
1638
1639 for (; __first1 != __last1 && __first2 != __last2;
1640 ++__first1, (void)++__first2)
1641 if (!bool(__binary_pred(*__first1, *__first2)))
1642 return false;
1643 return __first1 == __last1 && __first2 == __last2;
1644 }
1645#endif // C++11
1646
1647#if __cplusplus > 201103L
1648
1649#define __cpp_lib_robust_nonmodifying_seq_ops 201304
1650
1651 /**
1652 * @brief Tests a range for element-wise equality.
1653 * @ingroup non_mutating_algorithms
1654 * @param __first1 An input iterator.
1655 * @param __last1 An input iterator.
1656 * @param __first2 An input iterator.
1657 * @param __last2 An input iterator.
1658 * @return A boolean true or false.
1659 *
1660 * This compares the elements of two ranges using @c == and returns true or
1661 * false depending on whether all of the corresponding elements of the
1662 * ranges are equal.
1663 */
1664 template<typename _II1, typename _II2>
1665 _GLIBCXX20_CONSTEXPR
1666 inline bool
1667 equal(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
1668 {
1669 // concept requirements
1670 __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1671 __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1672 __glibcxx_function_requires(_EqualOpConcept<
1673 typename iterator_traits<_II1>::value_type,
1674 typename iterator_traits<_II2>::value_type>)
1675 __glibcxx_requires_valid_range(__first1, __last1);
1676 __glibcxx_requires_valid_range(__first2, __last2);
1677
1678 return _GLIBCXX_STD_A::__equal4(__first1, __last1, __first2, __last2);
1679 }
1680
1681 /**
1682 * @brief Tests a range for element-wise equality.
1683 * @ingroup non_mutating_algorithms
1684 * @param __first1 An input iterator.
1685 * @param __last1 An input iterator.
1686 * @param __first2 An input iterator.
1687 * @param __last2 An input iterator.
1688 * @param __binary_pred A binary predicate @link functors
1689 * functor@endlink.
1690 * @return A boolean true or false.
1691 *
1692 * This compares the elements of two ranges using the binary_pred
1693 * parameter, and returns true or
1694 * false depending on whether all of the corresponding elements of the
1695 * ranges are equal.
1696 */
1697 template<typename _IIter1, typename _IIter2, typename _BinaryPredicate>
1698 _GLIBCXX20_CONSTEXPR
1699 inline bool
1700 equal(_IIter1 __first1, _IIter1 __last1,
1701 _IIter2 __first2, _IIter2 __last2, _BinaryPredicate __binary_pred)
1702 {
1703 // concept requirements
1704 __glibcxx_function_requires(_InputIteratorConcept<_IIter1>)
1705 __glibcxx_function_requires(_InputIteratorConcept<_IIter2>)
1706 __glibcxx_requires_valid_range(__first1, __last1);
1707 __glibcxx_requires_valid_range(__first2, __last2);
1708
1709 return _GLIBCXX_STD_A::__equal4(__first1, __last1, __first2, __last2,
1710 __binary_pred);
1711 }
1712#endif // C++14
1713
1714 /**
1715 * @brief Performs @b dictionary comparison on ranges.
1716 * @ingroup sorting_algorithms
1717 * @param __first1 An input iterator.
1718 * @param __last1 An input iterator.
1719 * @param __first2 An input iterator.
1720 * @param __last2 An input iterator.
1721 * @return A boolean true or false.
1722 *
1723 * <em>Returns true if the sequence of elements defined by the range
1724 * [first1,last1) is lexicographically less than the sequence of elements
1725 * defined by the range [first2,last2). Returns false otherwise.</em>
1726 * (Quoted from [25.3.8]/1.) If the iterators are all character pointers,
1727 * then this is an inline call to @c memcmp.
1728 */
1729 template<typename _II1, typename _II2>
1730 _GLIBCXX20_CONSTEXPR
1731 inline bool
1732 lexicographical_compare(_II1 __first1, _II1 __last1,
1733 _II2 __first2, _II2 __last2)
1734 {
1735#ifdef _GLIBCXX_CONCEPT_CHECKS
1736 // concept requirements
1737 typedef typename iterator_traits<_II1>::value_type _ValueType1;
1738 typedef typename iterator_traits<_II2>::value_type _ValueType2;
1739#endif
1740 __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1741 __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1742 __glibcxx_function_requires(_LessThanOpConcept<_ValueType1, _ValueType2>)
1743 __glibcxx_function_requires(_LessThanOpConcept<_ValueType2, _ValueType1>)
1744 __glibcxx_requires_valid_range(__first1, __last1);
1745 __glibcxx_requires_valid_range(__first2, __last2);
1746
1747 return std::__lexicographical_compare_aux(__first1, __last1,
1748 __first2, __last2);
1749 }
1750
1751 /**
1752 * @brief Performs @b dictionary comparison on ranges.
1753 * @ingroup sorting_algorithms
1754 * @param __first1 An input iterator.
1755 * @param __last1 An input iterator.
1756 * @param __first2 An input iterator.
1757 * @param __last2 An input iterator.
1758 * @param __comp A @link comparison_functors comparison functor@endlink.
1759 * @return A boolean true or false.
1760 *
1761 * The same as the four-parameter @c lexicographical_compare, but uses the
1762 * comp parameter instead of @c <.
1763 */
1764 template<typename _II1, typename _II2, typename _Compare>
1765 _GLIBCXX20_CONSTEXPR
1766 inline bool
1767 lexicographical_compare(_II1 __first1, _II1 __last1,
1768 _II2 __first2, _II2 __last2, _Compare __comp)
1769 {
1770 // concept requirements
1771 __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1772 __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1773 __glibcxx_requires_valid_range(__first1, __last1);
1774 __glibcxx_requires_valid_range(__first2, __last2);
1775
1776 return std::__lexicographical_compare_impl
1777 (__first1, __last1, __first2, __last2,
1778 __gnu_cxx::__ops::__iter_comp_iter(__comp));
1779 }
1780
1781#if __cpp_lib_three_way_comparison
1782 // Iter points to a contiguous range of unsigned narrow character type
1783 // or std::byte, suitable for comparison by memcmp.
1784 template<typename _Iter>
1785 concept __is_byte_iter = contiguous_iterator<_Iter>
1786 && __is_memcmp_ordered<iter_value_t<_Iter>>::__value;
1787
1788 // Return a struct with two members, initialized to the smaller of x and y
1789 // (or x if they compare equal) and the result of the comparison x <=> y.
1790 template<typename _Tp>
1791 constexpr auto
1792 __min_cmp(_Tp __x, _Tp __y)
1793 {
1794 struct _Res {
1795 _Tp _M_min;
1796 decltype(__x <=> __y) _M_cmp;
1797 };
1798 auto __c = __x <=> __y;
1799 if (__c > 0)
1800 return _Res{__y, __c};
1801 return _Res{__x, __c};
1802 }
1803
1804 /**
1805 * @brief Performs dictionary comparison on ranges.
1806 * @ingroup sorting_algorithms
1807 * @param __first1 An input iterator.
1808 * @param __last1 An input iterator.
1809 * @param __first2 An input iterator.
1810 * @param __last2 An input iterator.
1811 * @param __comp A @link comparison_functors comparison functor@endlink.
1812 * @return The comparison category that `__comp(*__first1, *__first2)`
1813 * returns.
1814 */
1815 template<typename _InputIter1, typename _InputIter2, typename _Comp>
1816 constexpr auto
1817 lexicographical_compare_three_way(_InputIter1 __first1,
1818 _InputIter1 __last1,
1819 _InputIter2 __first2,
1820 _InputIter2 __last2,
1821 _Comp __comp)
1822 -> decltype(__comp(*__first1, *__first2))
1823 {
1824 // concept requirements
1825 __glibcxx_function_requires(_InputIteratorConcept<_InputIter1>)
1826 __glibcxx_function_requires(_InputIteratorConcept<_InputIter2>)
1827 __glibcxx_requires_valid_range(__first1, __last1);
1828 __glibcxx_requires_valid_range(__first2, __last2);
1829
1830#if __cpp_lib_is_constant_evaluated
1831 using _Cat = decltype(__comp(*__first1, *__first2));
1832 static_assert(same_as<common_comparison_category_t<_Cat>, _Cat>);
1833
1834 if (!std::is_constant_evaluated())
1835 if constexpr (same_as<_Comp, __detail::_Synth3way>
1836 || same_as<_Comp, compare_three_way>)
1837 if constexpr (__is_byte_iter<_InputIter1>)
1838 if constexpr (__is_byte_iter<_InputIter2>)
1839 {
1840 const auto [__len, __lencmp] = _GLIBCXX_STD_A::
1841 __min_cmp(__last1 - __first1, __last2 - __first2);
1842 if (__len)
1843 {
1844 const auto __c
1845 = __builtin_memcmp(&*__first1, &*__first2, __len) <=> 0;
1846 if (__c != 0)
1847 return __c;
1848 }
1849 return __lencmp;
1850 }
1851#endif // is_constant_evaluated
1852 while (__first1 != __last1)
1853 {
1854 if (__first2 == __last2)
1855 return strong_ordering::greater;
1856 if (auto __cmp = __comp(*__first1, *__first2); __cmp != 0)
1857 return __cmp;
1858 ++__first1;
1859 ++__first2;
1860 }
1861 return (__first2 == __last2) <=> true; // See PR 94006
1862 }
1863
1864 template<typename _InputIter1, typename _InputIter2>
1865 constexpr auto
1866 lexicographical_compare_three_way(_InputIter1 __first1,
1867 _InputIter1 __last1,
1868 _InputIter2 __first2,
1869 _InputIter2 __last2)
1870 {
1871 return _GLIBCXX_STD_A::
1872 lexicographical_compare_three_way(__first1, __last1, __first2, __last2,
1873 compare_three_way{});
1874 }
1875#endif // three_way_comparison
1876
1877 template<typename _InputIterator1, typename _InputIterator2,
1878 typename _BinaryPredicate>
1879 _GLIBCXX20_CONSTEXPR
1880 pair<_InputIterator1, _InputIterator2>
1881 __mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1882 _InputIterator2 __first2, _BinaryPredicate __binary_pred)
1883 {
1884 while (__first1 != __last1 && __binary_pred(__first1, __first2))
1885 {
1886 ++__first1;
1887 ++__first2;
1888 }
1889 return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
1890 }
1891
1892 /**
1893 * @brief Finds the places in ranges which don't match.
1894 * @ingroup non_mutating_algorithms
1895 * @param __first1 An input iterator.
1896 * @param __last1 An input iterator.
1897 * @param __first2 An input iterator.
1898 * @return A pair of iterators pointing to the first mismatch.
1899 *
1900 * This compares the elements of two ranges using @c == and returns a pair
1901 * of iterators. The first iterator points into the first range, the
1902 * second iterator points into the second range, and the elements pointed
1903 * to by the iterators are not equal.
1904 */
1905 template<typename _InputIterator1, typename _InputIterator2>
1906 _GLIBCXX20_CONSTEXPR
1907 inline pair<_InputIterator1, _InputIterator2>
1908 mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1909 _InputIterator2 __first2)
1910 {
1911 // concept requirements
1912 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
1913 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
1914 __glibcxx_function_requires(_EqualOpConcept<
1915 typename iterator_traits<_InputIterator1>::value_type,
1916 typename iterator_traits<_InputIterator2>::value_type>)
1917 __glibcxx_requires_valid_range(__first1, __last1);
1918
1919 return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2,
1920 __gnu_cxx::__ops::__iter_equal_to_iter());
1921 }
1922
1923 /**
1924 * @brief Finds the places in ranges which don't match.
1925 * @ingroup non_mutating_algorithms
1926 * @param __first1 An input iterator.
1927 * @param __last1 An input iterator.
1928 * @param __first2 An input iterator.
1929 * @param __binary_pred A binary predicate @link functors
1930 * functor@endlink.
1931 * @return A pair of iterators pointing to the first mismatch.
1932 *
1933 * This compares the elements of two ranges using the binary_pred
1934 * parameter, and returns a pair
1935 * of iterators. The first iterator points into the first range, the
1936 * second iterator points into the second range, and the elements pointed
1937 * to by the iterators are not equal.
1938 */
1939 template<typename _InputIterator1, typename _InputIterator2,
1940 typename _BinaryPredicate>
1941 _GLIBCXX20_CONSTEXPR
1942 inline pair<_InputIterator1, _InputIterator2>
1943 mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1944 _InputIterator2 __first2, _BinaryPredicate __binary_pred)
1945 {
1946 // concept requirements
1947 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
1948 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
1949 __glibcxx_requires_valid_range(__first1, __last1);
1950
1951 return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2,
1952 __gnu_cxx::__ops::__iter_comp_iter(__binary_pred));
1953 }
1954
1955#if __cplusplus > 201103L
1956
1957 template<typename _InputIterator1, typename _InputIterator2,
1958 typename _BinaryPredicate>
1959 _GLIBCXX20_CONSTEXPR
1960 pair<_InputIterator1, _InputIterator2>
1961 __mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1962 _InputIterator2 __first2, _InputIterator2 __last2,
1963 _BinaryPredicate __binary_pred)
1964 {
1965 while (__first1 != __last1 && __first2 != __last2
1966 && __binary_pred(__first1, __first2))
1967 {
1968 ++__first1;
1969 ++__first2;
1970 }
1971 return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
1972 }
1973
1974 /**
1975 * @brief Finds the places in ranges which don't match.
1976 * @ingroup non_mutating_algorithms
1977 * @param __first1 An input iterator.
1978 * @param __last1 An input iterator.
1979 * @param __first2 An input iterator.
1980 * @param __last2 An input iterator.
1981 * @return A pair of iterators pointing to the first mismatch.
1982 *
1983 * This compares the elements of two ranges using @c == and returns a pair
1984 * of iterators. The first iterator points into the first range, the
1985 * second iterator points into the second range, and the elements pointed
1986 * to by the iterators are not equal.
1987 */
1988 template<typename _InputIterator1, typename _InputIterator2>
1989 _GLIBCXX20_CONSTEXPR
1990 inline pair<_InputIterator1, _InputIterator2>
1991 mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1992 _InputIterator2 __first2, _InputIterator2 __last2)
1993 {
1994 // concept requirements
1995 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
1996 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
1997 __glibcxx_function_requires(_EqualOpConcept<
1998 typename iterator_traits<_InputIterator1>::value_type,
1999 typename iterator_traits<_InputIterator2>::value_type>)
2000 __glibcxx_requires_valid_range(__first1, __last1);
2001 __glibcxx_requires_valid_range(__first2, __last2);
2002
2003 return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2, __last2,
2004 __gnu_cxx::__ops::__iter_equal_to_iter());
2005 }
2006
2007 /**
2008 * @brief Finds the places in ranges which don't match.
2009 * @ingroup non_mutating_algorithms
2010 * @param __first1 An input iterator.
2011 * @param __last1 An input iterator.
2012 * @param __first2 An input iterator.
2013 * @param __last2 An input iterator.
2014 * @param __binary_pred A binary predicate @link functors
2015 * functor@endlink.
2016 * @return A pair of iterators pointing to the first mismatch.
2017 *
2018 * This compares the elements of two ranges using the binary_pred
2019 * parameter, and returns a pair
2020 * of iterators. The first iterator points into the first range, the
2021 * second iterator points into the second range, and the elements pointed
2022 * to by the iterators are not equal.
2023 */
2024 template<typename _InputIterator1, typename _InputIterator2,
2025 typename _BinaryPredicate>
2026 _GLIBCXX20_CONSTEXPR
2027 inline pair<_InputIterator1, _InputIterator2>
2028 mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
2029 _InputIterator2 __first2, _InputIterator2 __last2,
2030 _BinaryPredicate __binary_pred)
2031 {
2032 // concept requirements
2033 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
2034 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
2035 __glibcxx_requires_valid_range(__first1, __last1);
2036 __glibcxx_requires_valid_range(__first2, __last2);
2037
2038 return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2, __last2,
2039 __gnu_cxx::__ops::__iter_comp_iter(__binary_pred));
2040 }
2041#endif
2042
2043_GLIBCXX_END_NAMESPACE_ALGO
2044
2045 /// This is an overload used by find algos for the Input Iterator case.
2046 template<typename _InputIterator, typename _Predicate>
2047 _GLIBCXX20_CONSTEXPR
2048 inline _InputIterator
2049 __find_if(_InputIterator __first, _InputIterator __last,
2050 _Predicate __pred, input_iterator_tag)
2051 {
2052 while (__first != __last && !__pred(__first))
2053 ++__first;
2054 return __first;
2055 }
2056
2057 /// This is an overload used by find algos for the RAI case.
2058 template<typename _RandomAccessIterator, typename _Predicate>
2059 _GLIBCXX20_CONSTEXPR
2060 _RandomAccessIterator
2061 __find_if(_RandomAccessIterator __first, _RandomAccessIterator __last,
2062 _Predicate __pred, random_access_iterator_tag)
2063 {
2064 typename iterator_traits<_RandomAccessIterator>::difference_type
2065 __trip_count = (__last - __first) >> 2;
2066
2067 for (; __trip_count > 0; --__trip_count)
2068 {
2069 if (__pred(__first))
2070 return __first;
2071 ++__first;
2072
2073 if (__pred(__first))
2074 return __first;
2075 ++__first;
2076
2077 if (__pred(__first))
2078 return __first;
2079 ++__first;
2080
2081 if (__pred(__first))
2082 return __first;
2083 ++__first;
2084 }
2085
2086 switch (__last - __first)
2087 {
2088 case 3:
2089 if (__pred(__first))
2090 return __first;
2091 ++__first;
2092 // FALLTHRU
2093 case 2:
2094 if (__pred(__first))
2095 return __first;
2096 ++__first;
2097 // FALLTHRU
2098 case 1:
2099 if (__pred(__first))
2100 return __first;
2101 ++__first;
2102 // FALLTHRU
2103 case 0:
2104 default:
2105 return __last;
2106 }
2107 }
2108
2109 template<typename _Iterator, typename _Predicate>
2110 _GLIBCXX20_CONSTEXPR
2111 inline _Iterator
2112 __find_if(_Iterator __first, _Iterator __last, _Predicate __pred)
2113 {
2114 return __find_if(__first, __last, __pred,
2115 std::__iterator_category(__first));
2116 }
2117
2118 template<typename _InputIterator, typename _Predicate>
2119 _GLIBCXX20_CONSTEXPR
2120 typename iterator_traits<_InputIterator>::difference_type
2121 __count_if(_InputIterator __first, _InputIterator __last, _Predicate __pred)
2122 {
2123 typename iterator_traits<_InputIterator>::difference_type __n = 0;
2124 for (; __first != __last; ++__first)
2125 if (__pred(__first))
2126 ++__n;
2127 return __n;
2128 }
2129
2130#if __cplusplus >= 201103L
2131 template<typename _ForwardIterator1, typename _ForwardIterator2,
2132 typename _BinaryPredicate>
2133 _GLIBCXX20_CONSTEXPR
2134 bool
2135 __is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
2136 _ForwardIterator2 __first2, _BinaryPredicate __pred)
2137 {
2138 // Efficiently compare identical prefixes: O(N) if sequences
2139 // have the same elements in the same order.
2140 for (; __first1 != __last1; ++__first1, (void)++__first2)
2141 if (!__pred(__first1, __first2))
2142 break;
2143
2144 if (__first1 == __last1)
2145 return true;
2146
2147 // Establish __last2 assuming equal ranges by iterating over the
2148 // rest of the list.
2149 _ForwardIterator2 __last2 = __first2;
2150 std::advance(__last2, std::distance(__first1, __last1));
2151 for (_ForwardIterator1 __scan = __first1; __scan != __last1; ++__scan)
2152 {
2153 if (__scan != std::__find_if(__first1, __scan,
2154 __gnu_cxx::__ops::__iter_comp_iter(__pred, __scan)))
2155 continue; // We've seen this one before.
2156
2157 auto __matches
2158 = std::__count_if(__first2, __last2,
2159 __gnu_cxx::__ops::__iter_comp_iter(__pred, __scan));
2160 if (0 == __matches ||
2161 std::__count_if(__scan, __last1,
2162 __gnu_cxx::__ops::__iter_comp_iter(__pred, __scan))
2163 != __matches)
2164 return false;
2165 }
2166 return true;
2167 }
2168
2169 /**
2170 * @brief Checks whether a permutation of the second sequence is equal
2171 * to the first sequence.
2172 * @ingroup non_mutating_algorithms
2173 * @param __first1 Start of first range.
2174 * @param __last1 End of first range.
2175 * @param __first2 Start of second range.
2176 * @return true if there exists a permutation of the elements in the range
2177 * [__first2, __first2 + (__last1 - __first1)), beginning with
2178 * ForwardIterator2 begin, such that equal(__first1, __last1, begin)
2179 * returns true; otherwise, returns false.
2180 */
2181 template<typename _ForwardIterator1, typename _ForwardIterator2>
2182 _GLIBCXX20_CONSTEXPR
2183 inline bool
2184 is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
2185 _ForwardIterator2 __first2)
2186 {
2187 // concept requirements
2188 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
2189 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
2190 __glibcxx_function_requires(_EqualOpConcept<
2191 typename iterator_traits<_ForwardIterator1>::value_type,
2192 typename iterator_traits<_ForwardIterator2>::value_type>)
2193 __glibcxx_requires_valid_range(__first1, __last1);
2194
2195 return std::__is_permutation(__first1, __last1, __first2,
2196 __gnu_cxx::__ops::__iter_equal_to_iter());
2197 }
2198#endif // C++11
2199
2200_GLIBCXX_END_NAMESPACE_VERSION
2201} // namespace std
2202
2203// NB: This file is included within many other C++ includes, as a way
2204// of getting the base algorithms. So, make sure that parallel bits
2205// come in too if requested.
2206#ifdef _GLIBCXX_PARALLEL
2207# include <parallel/algobase.h>
2208#endif
2209
2210#endif
2211