libstdc++
stl_algobase.h
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1// Core algorithmic facilities -*- C++ -*-
2
3// Copyright (C) 2001-2026 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/cpp_type_traits.h>
61#include <ext/type_traits.h>
62#include <ext/numeric_traits.h>
63#include <bits/stl_pair.h>
64#include <bits/stl_iterator_base_types.h>
65#include <bits/stl_iterator_base_funcs.h>
66#include <bits/stl_iterator.h>
67#include <bits/concept_check.h>
68#include <debug/debug.h>
69#include <bits/move.h> // For std::swap
70#include <bits/predefined_ops.h>
71#if __cplusplus >= 201103L
72# include <type_traits>
73#endif
74#if __cplusplus >= 201402L
75# include <bit> // std::__bit_width
76#endif
77#if __cplusplus >= 202002L
78# include <compare>
79# include <bits/ptr_traits.h> // std::to_address
80#endif
81
82namespace std _GLIBCXX_VISIBILITY(default)
83{
84_GLIBCXX_BEGIN_NAMESPACE_VERSION
85
86 /*
87 * A constexpr wrapper for __builtin_memcmp.
88 * @param __num The number of elements of type _Tp (not bytes).
89 */
90 template<typename _Tp, typename _Up>
91 _GLIBCXX14_CONSTEXPR
92 inline int
93 __memcmp(const _Tp* __first1, const _Up* __first2, size_t __num)
94 {
95#if __cplusplus >= 201103L
96 static_assert(sizeof(_Tp) == sizeof(_Up), "can be compared with memcmp");
97#endif
98#ifdef __cpp_lib_is_constant_evaluated
99 if (std::is_constant_evaluated())
100 {
101 for(; __num > 0; ++__first1, ++__first2, --__num)
102 if (*__first1 != *__first2)
103 return *__first1 < *__first2 ? -1 : 1;
104 return 0;
105 }
106 else
107#endif
108 return __builtin_memcmp(__first1, __first2, sizeof(_Tp) * __num);
109 }
110
111#if __cplusplus < 201103L
112 // See http://gcc.gnu.org/ml/libstdc++/2004-08/msg00167.html: in a
113 // nutshell, we are partially implementing the resolution of DR 187,
114 // when it's safe, i.e., the value_types are equal.
115 template<bool _BoolType>
116 struct __iter_swap
117 {
118 template<typename _ForwardIterator1, typename _ForwardIterator2>
119 static void
120 iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
121 {
122 typedef typename iterator_traits<_ForwardIterator1>::value_type
123 _ValueType1;
124 _ValueType1 __tmp = *__a;
125 *__a = *__b;
126 *__b = __tmp;
127 }
128 };
129
130 template<>
131 struct __iter_swap<true>
132 {
133 template<typename _ForwardIterator1, typename _ForwardIterator2>
134 static void
135 iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
136 {
137 swap(*__a, *__b);
138 }
139 };
140#endif // C++03
141
142 /**
143 * @brief Swaps the contents of two iterators.
144 * @ingroup mutating_algorithms
145 * @param __a An iterator.
146 * @param __b Another iterator.
147 *
148 * This function swaps the values pointed to by two iterators, not the
149 * iterators themselves.
150 */
151 template<typename _ForwardIterator1, typename _ForwardIterator2>
152 _GLIBCXX20_CONSTEXPR
153 inline void
154 iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
155 {
156 // concept requirements
157 __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
158 _ForwardIterator1>)
159 __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
160 _ForwardIterator2>)
161
162#if __cplusplus < 201103L
163 typedef typename iterator_traits<_ForwardIterator1>::value_type
164 _ValueType1;
165 typedef typename iterator_traits<_ForwardIterator2>::value_type
166 _ValueType2;
167
168 __glibcxx_function_requires(_ConvertibleConcept<_ValueType1,
169 _ValueType2>)
170 __glibcxx_function_requires(_ConvertibleConcept<_ValueType2,
171 _ValueType1>)
172
173 typedef typename iterator_traits<_ForwardIterator1>::reference
174 _ReferenceType1;
175 typedef typename iterator_traits<_ForwardIterator2>::reference
176 _ReferenceType2;
177 std::__iter_swap<__are_same<_ValueType1, _ValueType2>::__value
178 && __are_same<_ValueType1&, _ReferenceType1>::__value
179 && __are_same<_ValueType2&, _ReferenceType2>::__value>::
180 iter_swap(__a, __b);
181#else
182 // _GLIBCXX_RESOLVE_LIB_DEFECTS
183 // 187. iter_swap underspecified
184 swap(*__a, *__b);
185#endif
186 }
187
188 /**
189 * @brief Swap the elements of two sequences.
190 * @ingroup mutating_algorithms
191 * @param __first1 A forward iterator.
192 * @param __last1 A forward iterator.
193 * @param __first2 A forward iterator.
194 * @return An iterator equal to @p first2+(last1-first1).
195 *
196 * Swaps each element in the range @p [first1,last1) with the
197 * corresponding element in the range @p [first2,(last1-first1)).
198 * The ranges must not overlap.
199 */
200 template<typename _ForwardIterator1, typename _ForwardIterator2>
201 _GLIBCXX20_CONSTEXPR
202 _ForwardIterator2
203 swap_ranges(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
204 _ForwardIterator2 __first2)
205 {
206 // concept requirements
207 __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
208 _ForwardIterator1>)
209 __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
210 _ForwardIterator2>)
211 __glibcxx_requires_valid_range(__first1, __last1);
212
213 for (; __first1 != __last1; ++__first1, (void)++__first2)
214 std::iter_swap(__first1, __first2);
215 return __first2;
216 }
217
218 /**
219 * @brief This does what you think it does.
220 * @ingroup sorting_algorithms
221 * @param __a A thing of arbitrary type.
222 * @param __b Another thing of arbitrary type.
223 * @return The lesser of the parameters.
224 *
225 * This is the simple classic generic implementation. It will work on
226 * temporary expressions, since they are only evaluated once, unlike a
227 * preprocessor macro.
228 */
229 template<typename _Tp>
230 _GLIBCXX_NODISCARD _GLIBCXX14_CONSTEXPR
231 inline const _Tp&
232 min(const _Tp& __a, const _Tp& __b)
233 {
234 // concept requirements
235 __glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
236 //return __b < __a ? __b : __a;
237 if (__b < __a)
238 return __b;
239 return __a;
240 }
241
242 /**
243 * @brief This does what you think it does.
244 * @ingroup sorting_algorithms
245 * @param __a A thing of arbitrary type.
246 * @param __b Another thing of arbitrary type.
247 * @return The greater of the parameters.
248 *
249 * This is the simple classic generic implementation. It will work on
250 * temporary expressions, since they are only evaluated once, unlike a
251 * preprocessor macro.
252 */
253 template<typename _Tp>
254 _GLIBCXX_NODISCARD _GLIBCXX14_CONSTEXPR
255 inline const _Tp&
256 max(const _Tp& __a, const _Tp& __b)
257 {
258 // concept requirements
259 __glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
260 //return __a < __b ? __b : __a;
261 if (__a < __b)
262 return __b;
263 return __a;
264 }
265
266 /**
267 * @brief This does what you think it does.
268 * @ingroup sorting_algorithms
269 * @param __a A thing of arbitrary type.
270 * @param __b Another thing of arbitrary type.
271 * @param __comp A @link comparison_functors comparison functor@endlink.
272 * @return The lesser of the parameters.
273 *
274 * This will work on temporary expressions, since they are only evaluated
275 * once, unlike a preprocessor macro.
276 */
277 template<typename _Tp, typename _Compare>
278 _GLIBCXX_NODISCARD _GLIBCXX14_CONSTEXPR
279 inline const _Tp&
280 min(const _Tp& __a, const _Tp& __b, _Compare __comp)
281 {
282 //return __comp(__b, __a) ? __b : __a;
283 if (__comp(__b, __a))
284 return __b;
285 return __a;
286 }
287
288 /**
289 * @brief This does what you think it does.
290 * @ingroup sorting_algorithms
291 * @param __a A thing of arbitrary type.
292 * @param __b Another thing of arbitrary type.
293 * @param __comp A @link comparison_functors comparison functor@endlink.
294 * @return The greater of the parameters.
295 *
296 * This will work on temporary expressions, since they are only evaluated
297 * once, unlike a preprocessor macro.
298 */
299 template<typename _Tp, typename _Compare>
300 _GLIBCXX_NODISCARD _GLIBCXX14_CONSTEXPR
301 inline const _Tp&
302 max(const _Tp& __a, const _Tp& __b, _Compare __comp)
303 {
304 //return __comp(__a, __b) ? __b : __a;
305 if (__comp(__a, __b))
306 return __b;
307 return __a;
308 }
309
310_GLIBCXX_BEGIN_NAMESPACE_CONTAINER
311
312 template<typename _Tp, typename _Ref, typename _Ptr>
313 struct _Deque_iterator;
314
315 struct _Bit_iterator;
316
317_GLIBCXX_END_NAMESPACE_CONTAINER
318
319#if _GLIBCXX_HOSTED
320 // Helpers for streambuf iterators (either istream or ostream).
321 // NB: avoid including <iosfwd>, relatively large.
322 template<typename _CharT>
323 struct char_traits;
324
325 template<typename _CharT, typename _Traits>
326 class istreambuf_iterator;
327
328 template<typename _CharT, typename _Traits>
329 class ostreambuf_iterator;
330
331 template<bool _IsMove, typename _CharT>
332 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
333 ostreambuf_iterator<_CharT, char_traits<_CharT> > >::__type
334 __copy_move_a2(_CharT*, _CharT*,
335 ostreambuf_iterator<_CharT, char_traits<_CharT> >);
336
337 template<bool _IsMove, typename _CharT>
338 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
339 ostreambuf_iterator<_CharT, char_traits<_CharT> > >::__type
340 __copy_move_a2(const _CharT*, const _CharT*,
341 ostreambuf_iterator<_CharT, char_traits<_CharT> >);
342
343 template<bool _IsMove, typename _CharT>
344 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
345 _CharT*>::__type
346 __copy_move_a2(istreambuf_iterator<_CharT, char_traits<_CharT> >,
347 istreambuf_iterator<_CharT, char_traits<_CharT> >, _CharT*);
348
349 template<bool _IsMove, typename _CharT>
350 typename __gnu_cxx::__enable_if<
351 __is_char<_CharT>::__value,
352 _GLIBCXX_STD_C::_Deque_iterator<_CharT, _CharT&, _CharT*> >::__type
353 __copy_move_a2(
354 istreambuf_iterator<_CharT, char_traits<_CharT> >,
355 istreambuf_iterator<_CharT, char_traits<_CharT> >,
356 _GLIBCXX_STD_C::_Deque_iterator<_CharT, _CharT&, _CharT*>);
357#endif // HOSTED
358
359#if __cpp_lib_concepts
360 template<typename _OutIter, typename _InIter, typename _Sent = _InIter>
361 concept __memcpyable_iterators
362 = contiguous_iterator<_OutIter> && contiguous_iterator<_InIter>
363 && sized_sentinel_for<_Sent, _InIter>
364 && requires (_OutIter __o, _InIter __i) {
365 requires !!__memcpyable<decltype(std::to_address(__o)),
366 decltype(std::to_address(__i))>::__value;
367 };
368#endif
369
370#if __cplusplus < 201103L
371 // Used by __copy_move_a2, __copy_n_a and __copy_move_backward_a2 to
372 // get raw pointers so that calls to __builtin_memmove will compile,
373 // because C++98 can't use 'if constexpr' so statements that use memmove
374 // with pointer arguments need to also compile for arbitrary iterator types.
375 template<typename _Iter> __attribute__((__always_inline__))
376 inline void* __ptr_or_null(_Iter) { return 0; }
377 template<typename _Tp> __attribute__((__always_inline__))
378 inline void* __ptr_or_null(_Tp* __p) { return (void*)__p; }
379# define _GLIBCXX_TO_ADDR(P) std::__ptr_or_null(P)
380 // Used to advance output iterators (std::advance requires InputIterator).
381 template<typename _Iter> __attribute__((__always_inline__))
382 inline void __ptr_advance(_Iter&, ptrdiff_t) { }
383 template<typename _Tp> __attribute__((__always_inline__))
384 inline void __ptr_advance(_Tp*& __p, ptrdiff_t __n) { __p += __n; }
385# define _GLIBCXX_ADVANCE(P, N) std::__ptr_advance(P, N)
386#else
387 // For C++11 mode the __builtin_memmove calls are guarded by 'if constexpr'
388 // so we know the iterators used with memmove are guaranteed to be pointers.
389# define _GLIBCXX_TO_ADDR(P) P
390# define _GLIBCXX_ADVANCE(P, N) P += N
391#endif
392
393#pragma GCC diagnostic push
394#pragma GCC diagnostic ignored "-Wc++17-extensions"
395 template<bool _IsMove, typename _OutIter, typename _InIter>
396 __attribute__((__always_inline__)) _GLIBCXX20_CONSTEXPR
397 inline void
398 __assign_one(_OutIter& __out, _InIter& __in)
399 {
400#if __cplusplus >= 201103L
401 if constexpr (_IsMove)
402 *__out = std::move(*__in);
403 else
404#endif
405 *__out = *__in;
406 }
407
408 template<bool _IsMove, typename _InIter, typename _Sent, typename _OutIter>
409 _GLIBCXX20_CONSTEXPR
410 inline _OutIter
411 __copy_move_a2(_InIter __first, _Sent __last, _OutIter __result)
412 {
413 typedef __decltype(*__first) _InRef;
414 typedef __decltype(*__result) _OutRef;
415 if _GLIBCXX_CONSTEXPR (!__is_trivially_assignable(_OutRef, _InRef))
416 { } /* Skip the optimizations and use the loop at the end. */
417 else if (std::__is_constant_evaluated())
418 { } /* Skip the optimizations and use the loop at the end. */
419 else if _GLIBCXX_CONSTEXPR (__memcpyable<_OutIter, _InIter>::__value)
420 {
421 ptrdiff_t __n = std::distance(__first, __last);
422 if (__builtin_expect(__n > 1, true))
423 {
424 __builtin_memmove(_GLIBCXX_TO_ADDR(__result),
425 _GLIBCXX_TO_ADDR(__first),
426 __n * sizeof(*__first));
427 _GLIBCXX_ADVANCE(__result, __n);
428 }
429 else if (__n == 1)
430 {
431 std::__assign_one<_IsMove>(__result, __first);
432 ++__result;
433 }
434 return __result;
435 }
436#if __cpp_lib_concepts
437 else if constexpr (__memcpyable_iterators<_OutIter, _InIter, _Sent>)
438 {
439 if (auto __n = __last - __first; __n > 1) [[likely]]
440 {
441 void* __dest = std::to_address(__result);
442 const void* __src = std::to_address(__first);
443 size_t __nbytes = __n * sizeof(iter_value_t<_InIter>);
444 // Advance the iterators and convert to pointers first.
445 // This gives the iterators a chance to do bounds checking.
446 (void) std::to_address(__result += __n);
447 (void) std::to_address(__first += __n);
448 __builtin_memmove(__dest, __src, __nbytes);
449 }
450 else if (__n == 1)
451 {
452 std::__assign_one<_IsMove>(__result, __first);
453 ++__result;
454 }
455 return __result;
456 }
457#endif
458
459 for (; __first != __last; ++__result, (void)++__first)
460 std::__assign_one<_IsMove>(__result, __first);
461 return __result;
462 }
463#pragma GCC diagnostic pop
464
465 template<bool _IsMove,
466 typename _Tp, typename _Ref, typename _Ptr, typename _OI>
467 _OI
468 __copy_move_a1(_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
469 _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
470 _OI);
471
472 template<bool _IsMove,
473 typename _ITp, typename _IRef, typename _IPtr, typename _OTp>
474 _GLIBCXX_STD_C::_Deque_iterator<_OTp, _OTp&, _OTp*>
475 __copy_move_a1(_GLIBCXX_STD_C::_Deque_iterator<_ITp, _IRef, _IPtr>,
476 _GLIBCXX_STD_C::_Deque_iterator<_ITp, _IRef, _IPtr>,
477 _GLIBCXX_STD_C::_Deque_iterator<_OTp, _OTp&, _OTp*>);
478
479 template<bool _IsMove, typename _II, typename _Tp>
480 typename __gnu_cxx::__enable_if<
481 __is_any_random_access_iter<_II>::__value,
482 _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*> >::__type
483 __copy_move_a1(_II, _II, _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*>);
484
485 template<bool _IsMove, typename _II, typename _OI>
486 __attribute__((__always_inline__))
487 _GLIBCXX20_CONSTEXPR
488 inline _OI
489 __copy_move_a1(_II __first, _II __last, _OI __result)
490 { return std::__copy_move_a2<_IsMove>(__first, __last, __result); }
491
492 template<bool _IsMove, typename _II, typename _OI>
493 __attribute__((__always_inline__))
494 _GLIBCXX20_CONSTEXPR
495 inline _OI
496 __copy_move_a(_II __first, _II __last, _OI __result)
497 {
498 return std::__niter_wrap(__result,
499 std::__copy_move_a1<_IsMove>(std::__niter_base(__first),
500 std::__niter_base(__last),
501 std::__niter_base(__result)));
502 }
503
504 template<bool _IsMove,
505 typename _Ite, typename _Seq, typename _Cat, typename _OI>
506 _GLIBCXX20_CONSTEXPR
507 _OI
508 __copy_move_a(const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
509 const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
510 _OI);
511
512 template<bool _IsMove,
513 typename _II, typename _Ite, typename _Seq, typename _Cat>
514 _GLIBCXX20_CONSTEXPR
515 __gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>
516 __copy_move_a(_II, _II,
517 const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&);
518
519 template<bool _IsMove,
520 typename _IIte, typename _ISeq, typename _ICat,
521 typename _OIte, typename _OSeq, typename _OCat>
522 _GLIBCXX20_CONSTEXPR
523 ::__gnu_debug::_Safe_iterator<_OIte, _OSeq, _OCat>
524 __copy_move_a(const ::__gnu_debug::_Safe_iterator<_IIte, _ISeq, _ICat>&,
525 const ::__gnu_debug::_Safe_iterator<_IIte, _ISeq, _ICat>&,
526 const ::__gnu_debug::_Safe_iterator<_OIte, _OSeq, _OCat>&);
527
528#pragma GCC diagnostic push
529#pragma GCC diagnostic ignored "-Wc++17-extensions" // for if-constexpr
530 template<typename _InputIterator, typename _Size, typename _OutputIterator>
531 _GLIBCXX20_CONSTEXPR
532 _OutputIterator
533 __copy_n_a(_InputIterator __first, _Size __n, _OutputIterator __result,
534 bool)
535 {
536 typedef __decltype(*__first) _InRef;
537 typedef __decltype(*__result) _OutRef;
538 if _GLIBCXX_CONSTEXPR (!__is_trivially_assignable(_OutRef, _InRef))
539 { } /* Skip the optimizations and use the loop at the end. */
540#ifdef __cpp_lib_is_constant_evaluated
541 else if (std::is_constant_evaluated())
542 { } /* Skip the optimizations and use the loop at the end. */
543#endif
544 else if _GLIBCXX_CONSTEXPR (__memcpyable<_OutputIterator,
545 _InputIterator>::__value)
546 {
547 if (__builtin_expect(__n > 1, true))
548 {
549 __builtin_memmove(_GLIBCXX_TO_ADDR(__result),
550 _GLIBCXX_TO_ADDR(__first),
551 __n * sizeof(*__first));
552 _GLIBCXX_ADVANCE(__result, __n);
553 }
554 else if (__n == 1)
555 *__result++ = *__first;
556 return __result;
557 }
558#if __cpp_lib_concepts
559 else if constexpr (__memcpyable_iterators<_OutputIterator,
560 _InputIterator>)
561 {
562 if (__n > 1) [[likely]]
563 {
564 void* __dest = std::to_address(__result);
565 const void* __src = std::to_address(__first);
566 size_t __nbytes = __n * sizeof(iter_value_t<_InputIterator>);
567 // Advance the iterators and convert to pointers first.
568 // This gives the iterators a chance to do bounds checking.
569 (void) std::to_address(__result += __n);
570 (void) std::to_address(__first += __n);
571 __builtin_memmove(__dest, __src, __nbytes);
572 }
573 else if (__n == 1)
574 *__result++ = *__first;
575 return __result;
576 }
577#endif
578
579 if (__n > 0)
580 {
581 while (true)
582 {
583 *__result = *__first;
584 ++__result;
585 if (--__n > 0)
586 ++__first;
587 else
588 break;
589 }
590 }
591 return __result;
592 }
593#pragma GCC diagnostic pop
594
595#if _GLIBCXX_HOSTED
596 template<typename _CharT, typename _Size>
597 typename __gnu_cxx::__enable_if<
598 __is_char<_CharT>::__value, _CharT*>::__type
599 __copy_n_a(istreambuf_iterator<_CharT, char_traits<_CharT> >,
600 _Size, _CharT*, bool);
601
602 template<typename _CharT, typename _Size>
603 typename __gnu_cxx::__enable_if<
604 __is_char<_CharT>::__value,
605 _GLIBCXX_STD_C::_Deque_iterator<_CharT, _CharT&, _CharT*> >::__type
606 __copy_n_a(istreambuf_iterator<_CharT, char_traits<_CharT> >, _Size,
607 _GLIBCXX_STD_C::_Deque_iterator<_CharT, _CharT&, _CharT*>,
608 bool);
609#endif
610
611 /**
612 * @brief Copies the range [first,last) into result.
613 * @ingroup mutating_algorithms
614 * @param __first An input iterator.
615 * @param __last An input iterator.
616 * @param __result An output iterator.
617 * @return result + (last - first)
618 *
619 * This inline function will boil down to a call to @c memmove whenever
620 * possible. Failing that, if random access iterators are passed, then the
621 * loop count will be known (and therefore a candidate for compiler
622 * optimizations such as unrolling). Result may not be contained within
623 * [first,last); the copy_backward function should be used instead.
624 *
625 * Note that the end of the output range is permitted to be contained
626 * within [first,last).
627 */
628 template<typename _II, typename _OI>
629 _GLIBCXX20_CONSTEXPR
630 inline _OI
631 copy(_II __first, _II __last, _OI __result)
632 {
633 // concept requirements
634 __glibcxx_function_requires(_InputIteratorConcept<_II>)
635 __glibcxx_function_requires(_OutputIteratorConcept<_OI,
636 typename iterator_traits<_II>::reference>)
637 __glibcxx_requires_can_increment_range(__first, __last, __result);
638
639 return std::__copy_move_a<__is_move_iterator<_II>::__value>
640 (std::__miter_base(__first), std::__miter_base(__last), __result);
641 }
642
643#if __cplusplus >= 201103L
644 /**
645 * @brief Moves the range [first,last) into result.
646 * @ingroup mutating_algorithms
647 * @param __first An input iterator.
648 * @param __last An input iterator.
649 * @param __result An output iterator.
650 * @return result + (last - first)
651 *
652 * This inline function will boil down to a call to @c memmove whenever
653 * possible. Failing that, if random access iterators are passed, then the
654 * loop count will be known (and therefore a candidate for compiler
655 * optimizations such as unrolling). Result may not be contained within
656 * [first,last); the move_backward function should be used instead.
657 *
658 * Note that the end of the output range is permitted to be contained
659 * within [first,last).
660 */
661 template<typename _II, typename _OI>
662 _GLIBCXX20_CONSTEXPR
663 inline _OI
664 move(_II __first, _II __last, _OI __result)
665 {
666 // concept requirements
667 __glibcxx_function_requires(_InputIteratorConcept<_II>)
668 __glibcxx_function_requires(_OutputIteratorConcept<_OI,
669 typename iterator_traits<_II>::value_type&&>)
670 __glibcxx_requires_can_increment_range(__first, __last, __result);
671
672 return std::__copy_move_a<true>(std::__miter_base(__first),
673 std::__miter_base(__last), __result);
674 }
675
676#define _GLIBCXX_MOVE3(_Tp, _Up, _Vp) std::move(_Tp, _Up, _Vp)
677#else
678#define _GLIBCXX_MOVE3(_Tp, _Up, _Vp) std::copy(_Tp, _Up, _Vp)
679#endif
680
681#pragma GCC diagnostic push
682#pragma GCC diagnostic ignored "-Wc++17-extensions"
683 template<bool _IsMove, typename _BI1, typename _BI2>
684 _GLIBCXX20_CONSTEXPR
685 inline _BI2
686 __copy_move_backward_a2(_BI1 __first, _BI1 __last, _BI2 __result)
687 {
688 typedef __decltype(*__first) _InRef;
689 typedef __decltype(*__result) _OutRef;
690 if _GLIBCXX_CONSTEXPR (!__is_trivially_assignable(_OutRef, _InRef))
691 { } /* Skip the optimizations and use the loop at the end. */
692#ifdef __cpp_lib_is_constant_evaluated
693 else if (std::is_constant_evaluated())
694 { } /* Skip the optimizations and use the loop at the end. */
695#endif
696 else if _GLIBCXX_CONSTEXPR (__memcpyable<_BI2, _BI1>::__value)
697 {
698 ptrdiff_t __n = std::distance(__first, __last);
699 std::advance(__result, -__n);
700 if (__builtin_expect(__n > 1, true))
701 {
702 __builtin_memmove(_GLIBCXX_TO_ADDR(__result),
703 _GLIBCXX_TO_ADDR(__first),
704 __n * sizeof(*__first));
705 }
706 else if (__n == 1)
707 std::__assign_one<_IsMove>(__result, __first);
708 return __result;
709 }
710#if __cpp_lib_concepts
711 else if constexpr (__memcpyable_iterators<_BI2, _BI1>)
712 {
713 if (auto __n = __last - __first; __n > 1) [[likely]]
714 {
715 const void* __src = std::to_address(__first);
716 // Advance the iterators and convert to pointers first.
717 // This gives the iterators a chance to do bounds checking.
718 (void) std::to_address(__result -= __n);
719 (void) std::to_address(__first += __n);
720 void* __dest = std::to_address(__result);
721 size_t __nbytes = __n * sizeof(iter_value_t<_BI1>);
722 __builtin_memmove(__dest, __src, __nbytes);
723 }
724 else if (__n == 1)
725 {
726 --__result;
727 std::__assign_one<_IsMove>(__result, __first);
728 }
729 return __result;
730 }
731#endif
732
733 while (__first != __last)
734 {
735 --__last;
736 --__result;
737 std::__assign_one<_IsMove>(__result, __last);
738 }
739 return __result;
740 }
741#pragma GCC diagnostic pop
742
743#undef _GLIBCXX_TO_ADDR
744#undef _GLIBCXX_ADVANCE
745
746 template<bool _IsMove, typename _BI1, typename _BI2>
747 __attribute__((__always_inline__))
748 _GLIBCXX20_CONSTEXPR
749 inline _BI2
750 __copy_move_backward_a1(_BI1 __first, _BI1 __last, _BI2 __result)
751 { return std::__copy_move_backward_a2<_IsMove>(__first, __last, __result); }
752
753 template<bool _IsMove,
754 typename _Tp, typename _Ref, typename _Ptr, typename _OI>
755 _OI
756 __copy_move_backward_a1(_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
757 _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
758 _OI);
759
760 template<bool _IsMove,
761 typename _ITp, typename _IRef, typename _IPtr, typename _OTp>
762 _GLIBCXX_STD_C::_Deque_iterator<_OTp, _OTp&, _OTp*>
763 __copy_move_backward_a1(
764 _GLIBCXX_STD_C::_Deque_iterator<_ITp, _IRef, _IPtr>,
765 _GLIBCXX_STD_C::_Deque_iterator<_ITp, _IRef, _IPtr>,
766 _GLIBCXX_STD_C::_Deque_iterator<_OTp, _OTp&, _OTp*>);
767
768 template<bool _IsMove, typename _II, typename _Tp>
769 typename __gnu_cxx::__enable_if<
770 __is_any_random_access_iter<_II>::__value,
771 _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*> >::__type
772 __copy_move_backward_a1(_II, _II,
773 _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*>);
774
775 template<bool _IsMove, typename _II, typename _OI>
776 __attribute__((__always_inline__))
777 _GLIBCXX20_CONSTEXPR
778 inline _OI
779 __copy_move_backward_a(_II __first, _II __last, _OI __result)
780 {
781 return std::__niter_wrap(__result,
782 std::__copy_move_backward_a1<_IsMove>
783 (std::__niter_base(__first), std::__niter_base(__last),
784 std::__niter_base(__result)));
785 }
786
787 template<bool _IsMove,
788 typename _Ite, typename _Seq, typename _Cat, typename _OI>
789 _GLIBCXX20_CONSTEXPR
790 _OI
791 __copy_move_backward_a(
792 const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
793 const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
794 _OI);
795
796 template<bool _IsMove,
797 typename _II, typename _Ite, typename _Seq, typename _Cat>
798 _GLIBCXX20_CONSTEXPR
799 __gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>
800 __copy_move_backward_a(_II, _II,
801 const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&);
802
803 template<bool _IsMove,
804 typename _IIte, typename _ISeq, typename _ICat,
805 typename _OIte, typename _OSeq, typename _OCat>
806 _GLIBCXX20_CONSTEXPR
807 ::__gnu_debug::_Safe_iterator<_OIte, _OSeq, _OCat>
808 __copy_move_backward_a(
809 const ::__gnu_debug::_Safe_iterator<_IIte, _ISeq, _ICat>&,
810 const ::__gnu_debug::_Safe_iterator<_IIte, _ISeq, _ICat>&,
811 const ::__gnu_debug::_Safe_iterator<_OIte, _OSeq, _OCat>&);
812
813 /**
814 * @brief Copies the range [first,last) into result.
815 * @ingroup mutating_algorithms
816 * @param __first A bidirectional iterator.
817 * @param __last A bidirectional iterator.
818 * @param __result A bidirectional iterator.
819 * @return result - (last - first)
820 *
821 * The function has the same effect as copy, but starts at the end of the
822 * range and works its way to the start, returning the start of the result.
823 * This inline function will boil down to a call to @c memmove whenever
824 * possible. Failing that, if random access iterators are passed, then the
825 * loop count will be known (and therefore a candidate for compiler
826 * optimizations such as unrolling).
827 *
828 * Result may not be in the range (first,last]. Use copy instead. Note
829 * that the start of the output range may overlap [first,last).
830 */
831 template<typename _BI1, typename _BI2>
832 __attribute__((__always_inline__))
833 _GLIBCXX20_CONSTEXPR
834 inline _BI2
835 copy_backward(_BI1 __first, _BI1 __last, _BI2 __result)
836 {
837 // concept requirements
838 __glibcxx_function_requires(_BidirectionalIteratorConcept<_BI1>)
839 __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<_BI2>)
840 __glibcxx_function_requires(_OutputIteratorConcept<_BI2,
841 typename iterator_traits<_BI1>::reference>)
842 __glibcxx_requires_can_decrement_range(__first, __last, __result);
843
844 return std::__copy_move_backward_a<__is_move_iterator<_BI1>::__value>
845 (std::__miter_base(__first), std::__miter_base(__last), __result);
846 }
847
848#if __cplusplus >= 201103L
849 /**
850 * @brief Moves the range [first,last) into result.
851 * @ingroup mutating_algorithms
852 * @param __first A bidirectional iterator.
853 * @param __last A bidirectional iterator.
854 * @param __result A bidirectional iterator.
855 * @return result - (last - first)
856 *
857 * The function has the same effect as move, but starts at the end of the
858 * range and works its way to the start, returning the start of the result.
859 * This inline function will boil down to a call to @c memmove whenever
860 * possible. Failing that, if random access iterators are passed, then the
861 * loop count will be known (and therefore a candidate for compiler
862 * optimizations such as unrolling).
863 *
864 * Result may not be in the range (first,last]. Use move instead. Note
865 * that the start of the output range may overlap [first,last).
866 */
867 template<typename _BI1, typename _BI2>
868 __attribute__((__always_inline__))
869 _GLIBCXX20_CONSTEXPR
870 inline _BI2
871 move_backward(_BI1 __first, _BI1 __last, _BI2 __result)
872 {
873 // concept requirements
874 __glibcxx_function_requires(_BidirectionalIteratorConcept<_BI1>)
875 __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<_BI2>)
876 __glibcxx_function_requires(_OutputIteratorConcept<_BI2,
877 typename iterator_traits<_BI1>::value_type&&>)
878 __glibcxx_requires_can_decrement_range(__first, __last, __result);
879
880 return std::__copy_move_backward_a<true>(std::__miter_base(__first),
881 std::__miter_base(__last),
882 __result);
883 }
884
885#define _GLIBCXX_MOVE_BACKWARD3(_Tp, _Up, _Vp) std::move_backward(_Tp, _Up, _Vp)
886#else
887#define _GLIBCXX_MOVE_BACKWARD3(_Tp, _Up, _Vp) std::copy_backward(_Tp, _Up, _Vp)
888#endif
889
890#pragma GCC diagnostic push
891#pragma GCC diagnostic ignored "-Wc++17-extensions"
892 template<typename _ForwardIterator, typename _Tp>
893 _GLIBCXX20_CONSTEXPR
894 inline void
895 __fill_a1(_ForwardIterator __first, _ForwardIterator __last,
896 const _Tp& __value)
897 {
898#pragma GCC diagnostic push
899#pragma GCC diagnostic ignored "-Wlong-long"
900 // We can optimize this loop by moving the load from __value outside
901 // the loop, but only if we know that making that copy is trivial,
902 // and the assignment in the loop is also trivial (so that the identity
903 // of the operand doesn't matter).
904 const bool __load_outside_loop =
905#if __has_builtin(__is_trivially_constructible) \
906 && __has_builtin(__is_trivially_assignable)
907 __is_trivially_constructible(_Tp, const _Tp&)
908 && __is_trivially_assignable(__decltype(*__first), const _Tp&)
909#else
910 __is_trivially_copyable(_Tp)
911 && __is_same(_Tp, __typeof__(*__first))
912#endif
913 && sizeof(_Tp) <= sizeof(long long);
914#pragma GCC diagnostic pop
915
916 // When the condition is true, we use a copy of __value,
917 // otherwise we just use another reference.
918 typedef typename __gnu_cxx::__conditional_type<__load_outside_loop,
919 const _Tp,
920 const _Tp&>::__type _Up;
921 _Up __val(__value);
922 for (; __first != __last; ++__first)
923 *__first = __val;
924 }
925#pragma GCC diagnostic pop
926
927 // Specialization: for char types we can use memset.
928 template<typename _Up, typename _Tp>
929 _GLIBCXX20_CONSTEXPR
930 inline typename
931 __gnu_cxx::__enable_if<__is_byte<_Up>::__value
932 && (__are_same<_Up, _Tp>::__value // for std::byte
933 || __memcpyable_integer<_Tp>::__width),
934 void>::__type
935 __fill_a1(_Up* __first, _Up* __last, const _Tp& __x)
936 {
937 // This hoists the load out of the loop and also ensures that we don't
938 // use memset for cases where the assignment would be ill-formed.
939 const _Up __val = __x;
940#if __cpp_lib_is_constant_evaluated
941 if (std::is_constant_evaluated())
942 {
943 for (; __first != __last; ++__first)
944 *__first = __val;
945 return;
946 }
947#endif
948 if (const size_t __len = __last - __first)
949 __builtin_memset(__first, static_cast<unsigned char>(__val), __len);
950 }
951
952 template<typename _Ite, typename _Cont, typename _Tp>
953 __attribute__((__always_inline__))
954 _GLIBCXX20_CONSTEXPR
955 inline void
956 __fill_a1(::__gnu_cxx::__normal_iterator<_Ite, _Cont> __first,
957 ::__gnu_cxx::__normal_iterator<_Ite, _Cont> __last,
958 const _Tp& __value)
959 { std::__fill_a1(__first.base(), __last.base(), __value); }
960
961 template<typename _Tp, typename _VTp>
962 void
963 __fill_a1(const _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*>&,
964 const _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*>&,
965 const _VTp&);
966
967 _GLIBCXX20_CONSTEXPR
968 void
969 __fill_a1(_GLIBCXX_STD_C::_Bit_iterator, _GLIBCXX_STD_C::_Bit_iterator,
970 const bool&);
971
972 template<typename _FIte, typename _Tp>
973 __attribute__((__always_inline__))
974 _GLIBCXX20_CONSTEXPR
975 inline void
976 __fill_a(_FIte __first, _FIte __last, const _Tp& __value)
977 { std::__fill_a1(__first, __last, __value); }
978
979 template<typename _Ite, typename _Seq, typename _Cat, typename _Tp>
980 _GLIBCXX20_CONSTEXPR
981 void
982 __fill_a(const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
983 const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
984 const _Tp&);
985
986 /**
987 * @brief Fills the range [first,last) with copies of value.
988 * @ingroup mutating_algorithms
989 * @param __first A forward iterator.
990 * @param __last A forward iterator.
991 * @param __value A reference-to-const of arbitrary type.
992 *
993 * This function fills a range with copies of the same value. For char
994 * types filling contiguous areas of memory, this becomes an inline call
995 * to @c memset or @c wmemset.
996 */
997 template<typename _ForwardIterator, typename _Tp>
998 __attribute__((__always_inline__))
999 _GLIBCXX20_CONSTEXPR
1000 inline void
1001 fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value)
1002 {
1003 // concept requirements
1004 __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
1005 _ForwardIterator>)
1006 __glibcxx_requires_valid_range(__first, __last);
1007
1008 std::__fill_a(__first, __last, __value);
1009 }
1010
1011#pragma GCC diagnostic push
1012#pragma GCC diagnostic ignored "-Wlong-long"
1013 // Used by fill_n, generate_n, etc. to convert _Size to an integral type:
1014 inline _GLIBCXX_CONSTEXPR int
1015 __size_to_integer(int __n) { return __n; }
1016 inline _GLIBCXX_CONSTEXPR unsigned
1017 __size_to_integer(unsigned __n) { return __n; }
1018 inline _GLIBCXX_CONSTEXPR long
1019 __size_to_integer(long __n) { return __n; }
1020 inline _GLIBCXX_CONSTEXPR unsigned long
1021 __size_to_integer(unsigned long __n) { return __n; }
1022 inline _GLIBCXX_CONSTEXPR long long
1023 __size_to_integer(long long __n) { return __n; }
1024 inline _GLIBCXX_CONSTEXPR unsigned long long
1025 __size_to_integer(unsigned long long __n) { return __n; }
1026
1027#if defined(__GLIBCXX_TYPE_INT_N_0)
1028 __extension__ inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_0
1029 __size_to_integer(__GLIBCXX_TYPE_INT_N_0 __n) { return __n; }
1030 __extension__ inline _GLIBCXX_CONSTEXPR unsigned __GLIBCXX_TYPE_INT_N_0
1031 __size_to_integer(unsigned __GLIBCXX_TYPE_INT_N_0 __n) { return __n; }
1032#endif
1033#if defined(__GLIBCXX_TYPE_INT_N_1)
1034 __extension__ inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_1
1035 __size_to_integer(__GLIBCXX_TYPE_INT_N_1 __n) { return __n; }
1036 __extension__ inline _GLIBCXX_CONSTEXPR unsigned __GLIBCXX_TYPE_INT_N_1
1037 __size_to_integer(unsigned __GLIBCXX_TYPE_INT_N_1 __n) { return __n; }
1038#endif
1039#if defined(__GLIBCXX_TYPE_INT_N_2)
1040 __extension__ inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_2
1041 __size_to_integer(__GLIBCXX_TYPE_INT_N_2 __n) { return __n; }
1042 __extension__ inline _GLIBCXX_CONSTEXPR unsigned __GLIBCXX_TYPE_INT_N_2
1043 __size_to_integer(unsigned __GLIBCXX_TYPE_INT_N_2 __n) { return __n; }
1044#endif
1045#if defined(__GLIBCXX_TYPE_INT_N_3)
1046 __extension__ inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_3
1047 __size_to_integer(__GLIBCXX_TYPE_INT_N_3 __n) { return __n; }
1048 __extension__ inline _GLIBCXX_CONSTEXPR unsigned __GLIBCXX_TYPE_INT_N_3
1049 __size_to_integer(unsigned __GLIBCXX_TYPE_INT_N_3 __n) { return __n; }
1050#endif
1051
1052#if defined(__STRICT_ANSI__) && defined(__SIZEOF_INT128__)
1053 __extension__ inline _GLIBCXX_CONSTEXPR __int128
1054 __size_to_integer(__int128 __n) { return __n; }
1055 __extension__ inline _GLIBCXX_CONSTEXPR unsigned __int128
1056 __size_to_integer(unsigned __int128 __n) { return __n; }
1057#endif
1058
1059 inline _GLIBCXX_CONSTEXPR long long
1060 __size_to_integer(float __n) { return (long long)__n; }
1061 inline _GLIBCXX_CONSTEXPR long long
1062 __size_to_integer(double __n) { return (long long)__n; }
1063 inline _GLIBCXX_CONSTEXPR long long
1064 __size_to_integer(long double __n) { return (long long)__n; }
1065#ifdef _GLIBCXX_USE_FLOAT128
1066 __extension__ inline _GLIBCXX_CONSTEXPR long long
1067 __size_to_integer(__float128 __n) { return (long long)__n; }
1068#endif
1069#pragma GCC diagnostic pop
1070
1071#pragma GCC diagnostic push
1072#pragma GCC diagnostic ignored "-Wc++17-extensions"
1073#pragma GCC diagnostic ignored "-Wlong-long"
1074 template<typename _OutputIterator, typename _Size, typename _Tp>
1075 _GLIBCXX20_CONSTEXPR
1076 inline _OutputIterator
1077 __fill_n_a1(_OutputIterator __first, _Size __n, const _Tp& __value)
1078 {
1079 // See std::__fill_a1 for explanation of this condition.
1080 const bool __load_outside_loop =
1081#if __has_builtin(__is_trivially_constructible) \
1082 && __has_builtin(__is_trivially_assignable)
1083 __is_trivially_constructible(_Tp, const _Tp&)
1084 && __is_trivially_assignable(__decltype(*__first), const _Tp&)
1085#else
1086 __is_trivially_copyable(_Tp)
1087 && __is_same(_Tp, __typeof__(*__first))
1088#endif
1089 && sizeof(_Tp) <= sizeof(long long);
1090
1091 // When the condition is true, we use a copy of __value,
1092 // otherwise we just use another reference.
1093 typedef typename __gnu_cxx::__conditional_type<__load_outside_loop,
1094 const _Tp,
1095 const _Tp&>::__type _Up;
1096 _Up __val(__value);
1097 for (; __n > 0; --__n, (void) ++__first)
1098 *__first = __val;
1099 return __first;
1100 }
1101#pragma GCC diagnostic pop
1102
1103 template<typename _Ite, typename _Seq, typename _Cat, typename _Size,
1104 typename _Tp>
1105 _GLIBCXX20_CONSTEXPR
1106 ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>
1107 __fill_n_a(const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>& __first,
1108 _Size __n, const _Tp& __value,
1109 std::input_iterator_tag);
1110
1111 template<typename _OutputIterator, typename _Size, typename _Tp>
1112 __attribute__((__always_inline__))
1113 _GLIBCXX20_CONSTEXPR
1114 inline _OutputIterator
1115 __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value,
1116 std::output_iterator_tag)
1117 {
1118#if __cplusplus >= 201103L
1119 static_assert(is_integral<_Size>{}, "fill_n must pass integral size");
1120#endif
1121 return __fill_n_a1(__first, __n, __value);
1122 }
1123
1124 template<typename _OutputIterator, typename _Size, typename _Tp>
1125 __attribute__((__always_inline__))
1126 _GLIBCXX20_CONSTEXPR
1127 inline _OutputIterator
1128 __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value,
1129 std::input_iterator_tag)
1130 {
1131#if __cplusplus >= 201103L
1132 static_assert(is_integral<_Size>{}, "fill_n must pass integral size");
1133#endif
1134 return __fill_n_a1(__first, __n, __value);
1135 }
1136
1137 template<typename _OutputIterator, typename _Size, typename _Tp>
1138 __attribute__((__always_inline__))
1139 _GLIBCXX20_CONSTEXPR
1140 inline _OutputIterator
1141 __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value,
1142 std::random_access_iterator_tag)
1143 {
1144#if __cplusplus >= 201103L
1145 static_assert(is_integral<_Size>{}, "fill_n must pass integral size");
1146#endif
1147 if (__n <= 0)
1148 return __first;
1149
1150 typename iterator_traits<_OutputIterator>::difference_type __d = __n;
1151 __glibcxx_requires_can_increment(__first, __d);
1152
1153 _OutputIterator __last = __first + __d;
1154 std::__fill_a(__first, __last, __value);
1155 return __last;
1156 }
1157
1158 /**
1159 * @brief Fills the range [first,first+n) with copies of value.
1160 * @ingroup mutating_algorithms
1161 * @param __first An output iterator.
1162 * @param __n The count of copies to perform.
1163 * @param __value A reference-to-const of arbitrary type.
1164 * @return The iterator at first+n.
1165 *
1166 * This function fills a range with copies of the same value. For char
1167 * types filling contiguous areas of memory, this becomes an inline call
1168 * to @c memset or @c wmemset.
1169 *
1170 * If @p __n is negative, the function does nothing.
1171 */
1172 // _GLIBCXX_RESOLVE_LIB_DEFECTS
1173 // DR 865. More algorithms that throw away information
1174 // DR 426. search_n(), fill_n(), and generate_n() with negative n
1175 template<typename _OI, typename _Size, typename _Tp>
1176 __attribute__((__always_inline__))
1177 _GLIBCXX20_CONSTEXPR
1178 inline _OI
1179 fill_n(_OI __first, _Size __n, const _Tp& __value)
1180 {
1181 // concept requirements
1182 __glibcxx_function_requires(_OutputIteratorConcept<_OI, const _Tp&>)
1183
1184 return std::__fill_n_a(__first, std::__size_to_integer(__n), __value,
1185 std::__iterator_category(__first));
1186 }
1187
1188 template<bool _BoolType>
1189 struct __equal
1190 {
1191 template<typename _II1, typename _II2>
1192 _GLIBCXX20_CONSTEXPR
1193 static bool
1194 equal(_II1 __first1, _II1 __last1, _II2 __first2)
1195 {
1196 for (; __first1 != __last1; ++__first1, (void) ++__first2)
1197 if (!(*__first1 == *__first2))
1198 return false;
1199 return true;
1200 }
1201 };
1202
1203 template<>
1204 struct __equal<true>
1205 {
1206 template<typename _Tp>
1207 _GLIBCXX20_CONSTEXPR
1208 static bool
1209 equal(const _Tp* __first1, const _Tp* __last1, const _Tp* __first2)
1210 {
1211 if (const size_t __len = (__last1 - __first1))
1212 return !std::__memcmp(__first1, __first2, __len);
1213 return true;
1214 }
1215 };
1216
1217 template<typename _Tp, typename _Ref, typename _Ptr, typename _II>
1218 typename __gnu_cxx::__enable_if<
1219 __is_any_random_access_iter<_II>::__value, bool>::__type
1220 __equal_aux1(_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
1221 _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
1222 _II);
1223
1224 template<typename _Tp1, typename _Ref1, typename _Ptr1,
1225 typename _Tp2, typename _Ref2, typename _Ptr2>
1226 bool
1227 __equal_aux1(_GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
1228 _GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
1229 _GLIBCXX_STD_C::_Deque_iterator<_Tp2, _Ref2, _Ptr2>);
1230
1231 template<typename _II, typename _Tp, typename _Ref, typename _Ptr>
1232 typename __gnu_cxx::__enable_if<
1233 __is_any_random_access_iter<_II>::__value, bool>::__type
1234 __equal_aux1(_II, _II,
1235 _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>);
1236
1237 template<typename _II1, typename _II2>
1238 _GLIBCXX20_CONSTEXPR
1239 inline bool
1240 __equal_aux1(_II1 __first1, _II1 __last1, _II2 __first2)
1241 {
1242 typedef typename iterator_traits<_II1>::value_type _ValueType1;
1243 const bool __simple = ((__is_integer<_ValueType1>::__value
1244#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_pointer)
1245 || __is_pointer(_ValueType1)
1246#endif
1247#if __glibcxx_byte && __glibcxx_type_trait_variable_templates
1248 // bits/cpp_type_traits.h declares std::byte
1249 || is_same_v<_ValueType1, byte>
1250#endif
1251 ) && __memcmpable<_II1, _II2>::__value);
1252 return std::__equal<__simple>::equal(__first1, __last1, __first2);
1253 }
1254
1255 template<typename _II1, typename _II2>
1256 __attribute__((__always_inline__))
1257 _GLIBCXX20_CONSTEXPR
1258 inline bool
1259 __equal_aux(_II1 __first1, _II1 __last1, _II2 __first2)
1260 {
1261 return std::__equal_aux1(std::__niter_base(__first1),
1262 std::__niter_base(__last1),
1263 std::__niter_base(__first2));
1264 }
1265
1266 template<typename _II1, typename _Seq1, typename _Cat1, typename _II2>
1267 _GLIBCXX20_CONSTEXPR
1268 bool
1269 __equal_aux(const ::__gnu_debug::_Safe_iterator<_II1, _Seq1, _Cat1>&,
1270 const ::__gnu_debug::_Safe_iterator<_II1, _Seq1, _Cat1>&,
1271 _II2);
1272
1273 template<typename _II1, typename _II2, typename _Seq2, typename _Cat2>
1274 _GLIBCXX20_CONSTEXPR
1275 bool
1276 __equal_aux(_II1, _II1,
1277 const ::__gnu_debug::_Safe_iterator<_II2, _Seq2, _Cat2>&);
1278
1279 template<typename _II1, typename _Seq1, typename _Cat1,
1280 typename _II2, typename _Seq2, typename _Cat2>
1281 _GLIBCXX20_CONSTEXPR
1282 bool
1283 __equal_aux(const ::__gnu_debug::_Safe_iterator<_II1, _Seq1, _Cat1>&,
1284 const ::__gnu_debug::_Safe_iterator<_II1, _Seq1, _Cat1>&,
1285 const ::__gnu_debug::_Safe_iterator<_II2, _Seq2, _Cat2>&);
1286
1287 template<typename, typename>
1288 struct __lc_rai
1289 {
1290 template<typename _II1, typename _II2>
1291 _GLIBCXX20_CONSTEXPR
1292 static _II1
1293 __newlast1(_II1, _II1 __last1, _II2, _II2)
1294 { return __last1; }
1295
1296 template<typename _II>
1297 _GLIBCXX20_CONSTEXPR
1298 static bool
1299 __cnd2(_II __first, _II __last)
1300 { return __first != __last; }
1301 };
1302
1303 template<>
1304 struct __lc_rai<random_access_iterator_tag, random_access_iterator_tag>
1305 {
1306 template<typename _RAI1, typename _RAI2>
1307 _GLIBCXX20_CONSTEXPR
1308 static _RAI1
1309 __newlast1(_RAI1 __first1, _RAI1 __last1,
1310 _RAI2 __first2, _RAI2 __last2)
1311 {
1312 typedef typename iterator_traits<_RAI1>::difference_type _Diff1;
1313 typedef typename iterator_traits<_RAI2>::difference_type _Diff2;
1314 const _Diff1 __diff1 = __last1 - __first1;
1315 const _Diff2 __diff2 = __last2 - __first2;
1316 return __diff2 < __diff1 ? __first1 + _Diff1(__diff2) : __last1;
1317 }
1318
1319 template<typename _RAI>
1320 static _GLIBCXX20_CONSTEXPR bool
1321 __cnd2(_RAI, _RAI)
1322 { return true; }
1323 };
1324
1325 template<typename _II1, typename _II2, typename _Compare>
1326 _GLIBCXX20_CONSTEXPR
1327 bool
1328 __lexicographical_compare_impl(_II1 __first1, _II1 __last1,
1329 _II2 __first2, _II2 __last2,
1330 _Compare __comp)
1331 {
1332 typedef __decltype(std::__iter_concept_or_category<_II1>()) _Category1;
1333 typedef __decltype(std::__iter_concept_or_category<_II2>()) _Category2;
1334 typedef std::__lc_rai<_Category1, _Category2> __rai_type;
1335
1336 __last1 = __rai_type::__newlast1(__first1, __last1, __first2, __last2);
1337 for (; __first1 != __last1 && __rai_type::__cnd2(__first2, __last2);
1338 ++__first1, (void)++__first2)
1339 {
1340 if (__comp(*__first1, *__first2))
1341 return true;
1342 if (__comp(*__first2, *__first1))
1343 return false;
1344 }
1345 return __first1 == __last1 && __first2 != __last2;
1346 }
1347
1348 template<bool _BoolType>
1349 struct __lexicographical_compare
1350 {
1351 template<typename _II1, typename _II2>
1352 _GLIBCXX20_CONSTEXPR
1353 static bool
1354 __lc(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
1355 {
1356 using __gnu_cxx::__ops::less;
1357 return std::__lexicographical_compare_impl(__first1, __last1,
1358 __first2, __last2,
1359 less());
1360 }
1361
1362 template<typename _II1, typename _II2>
1363 _GLIBCXX20_CONSTEXPR
1364 static int
1365 __3way(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
1366 {
1367 while (__first1 != __last1)
1368 {
1369 if (__first2 == __last2)
1370 return +1;
1371 if (*__first1 < *__first2)
1372 return -1;
1373 if (*__first2 < *__first1)
1374 return +1;
1375 ++__first1;
1376 ++__first2;
1377 }
1378 return int(__first2 == __last2) - 1;
1379 }
1380 };
1381
1382 template<>
1383 struct __lexicographical_compare<true>
1384 {
1385 template<typename _Tp, typename _Up>
1386 _GLIBCXX20_CONSTEXPR
1387 static bool
1388 __lc(const _Tp* __first1, const _Tp* __last1,
1389 const _Up* __first2, const _Up* __last2)
1390 { return __3way(__first1, __last1, __first2, __last2) < 0; }
1391
1392 template<typename _Tp, typename _Up>
1393 _GLIBCXX20_CONSTEXPR
1394 static ptrdiff_t
1395 __3way(const _Tp* __first1, const _Tp* __last1,
1396 const _Up* __first2, const _Up* __last2)
1397 {
1398 const size_t __len1 = __last1 - __first1;
1399 const size_t __len2 = __last2 - __first2;
1400 if (const size_t __len = std::min(__len1, __len2))
1401 if (int __result = std::__memcmp(__first1, __first2, __len))
1402 return __result;
1403 return ptrdiff_t(__len1 - __len2);
1404 }
1405 };
1406
1407 template<typename _II1, typename _II2>
1408 _GLIBCXX20_CONSTEXPR
1409 inline bool
1410 __lexicographical_compare_aux1(_II1 __first1, _II1 __last1,
1411 _II2 __first2, _II2 __last2)
1412 {
1413 typedef typename iterator_traits<_II1>::value_type _ValueType1;
1414 typedef typename iterator_traits<_II2>::value_type _ValueType2;
1415#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_pointer)
1416 const bool __simple =
1417 (__is_memcmp_ordered_with<_ValueType1, _ValueType2>::__value
1418 && __is_pointer(_II1) && __is_pointer(_II2)
1419#if __cplusplus > 201703L && __glibcxx_concepts
1420 // For C++20 iterator_traits<volatile T*>::value_type is non-volatile
1421 // so __is_byte<T> could be true, but we can't use memcmp with
1422 // volatile data.
1423 && !is_volatile_v<remove_reference_t<iter_reference_t<_II1>>>
1424 && !is_volatile_v<remove_reference_t<iter_reference_t<_II2>>>
1425#endif
1426 );
1427#else
1428 const bool __simple = false;
1429#endif
1430
1431 return std::__lexicographical_compare<__simple>::__lc(__first1, __last1,
1432 __first2, __last2);
1433 }
1434
1435 template<typename _Tp1, typename _Ref1, typename _Ptr1,
1436 typename _Tp2>
1437 bool
1438 __lexicographical_compare_aux1(
1439 _GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
1440 _GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
1441 _Tp2*, _Tp2*);
1442
1443 template<typename _Tp1,
1444 typename _Tp2, typename _Ref2, typename _Ptr2>
1445 bool
1446 __lexicographical_compare_aux1(_Tp1*, _Tp1*,
1447 _GLIBCXX_STD_C::_Deque_iterator<_Tp2, _Ref2, _Ptr2>,
1448 _GLIBCXX_STD_C::_Deque_iterator<_Tp2, _Ref2, _Ptr2>);
1449
1450 template<typename _Tp1, typename _Ref1, typename _Ptr1,
1451 typename _Tp2, typename _Ref2, typename _Ptr2>
1452 bool
1453 __lexicographical_compare_aux1(
1454 _GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
1455 _GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
1456 _GLIBCXX_STD_C::_Deque_iterator<_Tp2, _Ref2, _Ptr2>,
1457 _GLIBCXX_STD_C::_Deque_iterator<_Tp2, _Ref2, _Ptr2>);
1458
1459 template<typename _II1, typename _II2>
1460 _GLIBCXX20_CONSTEXPR
1461 inline bool
1462 __lexicographical_compare_aux(_II1 __first1, _II1 __last1,
1463 _II2 __first2, _II2 __last2)
1464 {
1465 return std::__lexicographical_compare_aux1(std::__niter_base(__first1),
1466 std::__niter_base(__last1),
1467 std::__niter_base(__first2),
1468 std::__niter_base(__last2));
1469 }
1470
1471 template<typename _Iter1, typename _Seq1, typename _Cat1,
1472 typename _II2>
1473 _GLIBCXX20_CONSTEXPR
1474 bool
1475 __lexicographical_compare_aux(
1476 const ::__gnu_debug::_Safe_iterator<_Iter1, _Seq1, _Cat1>&,
1477 const ::__gnu_debug::_Safe_iterator<_Iter1, _Seq1, _Cat1>&,
1478 _II2, _II2);
1479
1480 template<typename _II1,
1481 typename _Iter2, typename _Seq2, typename _Cat2>
1482 _GLIBCXX20_CONSTEXPR
1483 bool
1484 __lexicographical_compare_aux(
1485 _II1, _II1,
1486 const ::__gnu_debug::_Safe_iterator<_Iter2, _Seq2, _Cat2>&,
1487 const ::__gnu_debug::_Safe_iterator<_Iter2, _Seq2, _Cat2>&);
1488
1489 template<typename _Iter1, typename _Seq1, typename _Cat1,
1490 typename _Iter2, typename _Seq2, typename _Cat2>
1491 _GLIBCXX20_CONSTEXPR
1492 bool
1493 __lexicographical_compare_aux(
1494 const ::__gnu_debug::_Safe_iterator<_Iter1, _Seq1, _Cat1>&,
1495 const ::__gnu_debug::_Safe_iterator<_Iter1, _Seq1, _Cat1>&,
1496 const ::__gnu_debug::_Safe_iterator<_Iter2, _Seq2, _Cat2>&,
1497 const ::__gnu_debug::_Safe_iterator<_Iter2, _Seq2, _Cat2>&);
1498
1499 template<typename _ForwardIterator, typename _Tp, typename _Compare>
1500 _GLIBCXX20_CONSTEXPR
1501 _ForwardIterator
1502 __lower_bound(_ForwardIterator __first, _ForwardIterator __last,
1503 const _Tp& __val, _Compare __comp)
1504 {
1505 typedef typename iterator_traits<_ForwardIterator>::difference_type
1506 _DistanceType;
1507
1508 _DistanceType __len = std::distance(__first, __last);
1509
1510 while (__len > 0)
1511 {
1512 _DistanceType __half = __len >> 1;
1513 _ForwardIterator __middle = __first;
1514 std::advance(__middle, __half);
1515 if (__comp(*__middle, __val))
1516 {
1517 __first = __middle;
1518 ++__first;
1519 __len = __len - __half - 1;
1520 }
1521 else
1522 __len = __half;
1523 }
1524 return __first;
1525 }
1526
1527 /**
1528 * @brief Finds the first position in which @a val could be inserted
1529 * without changing the ordering.
1530 * @param __first An iterator.
1531 * @param __last Another iterator.
1532 * @param __val The search term.
1533 * @return An iterator pointing to the first element <em>not less
1534 * than</em> @a val, or end() if every element is less than
1535 * @a val.
1536 * @ingroup binary_search_algorithms
1537 */
1538 template<typename _ForwardIterator, typename _Tp>
1539 _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
1540 inline _ForwardIterator
1541 lower_bound(_ForwardIterator __first, _ForwardIterator __last,
1542 const _Tp& __val)
1543 {
1544 // concept requirements
1545 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
1546 __glibcxx_function_requires(_LessThanOpConcept<
1547 typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
1548 __glibcxx_requires_partitioned_lower(__first, __last, __val);
1549
1550 return std::__lower_bound(__first, __last, __val,
1551 __gnu_cxx::__ops::less());
1552 }
1553
1554 /// This is a helper function for the sort routines and for random.tcc.
1555 // Precondition: __n > 0.
1556 template<typename _Tp>
1557 inline _GLIBCXX_CONSTEXPR _Tp
1558 __lg(_Tp __n)
1559 {
1560#if __cplusplus >= 201402L
1561 return std::__bit_width(make_unsigned_t<_Tp>(__n)) - 1;
1562#else
1563#pragma GCC diagnostic push
1564#pragma GCC diagnostic ignored "-Wlong-long"
1565 // Use +__n so it promotes to at least int.
1566 return (sizeof(+__n) * __CHAR_BIT__ - 1)
1567 - (sizeof(+__n) == sizeof(long long)
1568 ? __builtin_clzll(+__n)
1569 : (sizeof(+__n) == sizeof(long)
1570 ? __builtin_clzl(+__n)
1571 : __builtin_clz(+__n)));
1572#pragma GCC diagnostic pop
1573#endif
1574 }
1575
1576_GLIBCXX_BEGIN_NAMESPACE_ALGO
1577
1578 /**
1579 * @brief Tests a range for element-wise equality.
1580 * @ingroup non_mutating_algorithms
1581 * @param __first1 An input iterator.
1582 * @param __last1 An input iterator.
1583 * @param __first2 An input iterator.
1584 * @return A boolean true or false.
1585 *
1586 * This compares the elements of two ranges using @c == and returns true or
1587 * false depending on whether all of the corresponding elements of the
1588 * ranges are equal.
1589 */
1590 template<typename _II1, typename _II2>
1591 _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
1592 inline bool
1593 equal(_II1 __first1, _II1 __last1, _II2 __first2)
1594 {
1595 // concept requirements
1596 __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1597 __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1598 __glibcxx_function_requires(_EqualOpConcept<
1599 typename iterator_traits<_II1>::value_type,
1600 typename iterator_traits<_II2>::value_type>)
1601 __glibcxx_requires_can_increment_range(__first1, __last1, __first2);
1602
1603 return std::__equal_aux(__first1, __last1, __first2);
1604 }
1605
1606 /**
1607 * @brief Tests a range for element-wise equality.
1608 * @ingroup non_mutating_algorithms
1609 * @param __first1 An input iterator.
1610 * @param __last1 An input iterator.
1611 * @param __first2 An input iterator.
1612 * @param __binary_pred A binary predicate @link functors
1613 * functor@endlink.
1614 * @return A boolean true or false.
1615 *
1616 * This compares the elements of two ranges using the binary_pred
1617 * parameter, and returns true or
1618 * false depending on whether all of the corresponding elements of the
1619 * ranges are equal.
1620 */
1621 template<typename _IIter1, typename _IIter2, typename _BinaryPredicate>
1622 _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
1623 inline bool
1624 equal(_IIter1 __first1, _IIter1 __last1,
1625 _IIter2 __first2, _BinaryPredicate __binary_pred)
1626 {
1627 // concept requirements
1628 __glibcxx_function_requires(_InputIteratorConcept<_IIter1>)
1629 __glibcxx_function_requires(_InputIteratorConcept<_IIter2>)
1630 __glibcxx_requires_valid_range(__first1, __last1);
1631
1632 for (; __first1 != __last1; ++__first1, (void)++__first2)
1633 if (!bool(__binary_pred(*__first1, *__first2)))
1634 return false;
1635 return true;
1636 }
1637
1638#if __cplusplus >= 201103L
1639#pragma GCC diagnostic push
1640#pragma GCC diagnostic ignored "-Wc++17-extensions" // if constexpr
1641
1642 // 4-iterator version of std::equal<It1, It2> for use in C++11.
1643 template<typename _II1, typename _II2>
1644 _GLIBCXX20_CONSTEXPR
1645 inline bool
1646 __equal4(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
1647 {
1648 using _RATag = random_access_iterator_tag;
1649 using _Cat1 = decltype(std::__iter_concept_or_category<_II1>());
1650 using _Cat2 = decltype(std::__iter_concept_or_category<_II2>());
1651 using _RAIters = __and_<is_same<_Cat1, _RATag>, is_same<_Cat2, _RATag>>;
1652 if constexpr (_RAIters::value)
1653 {
1654 if ((__last1 - __first1) != (__last2 - __first2))
1655 return false;
1656 return _GLIBCXX_STD_A::equal(__first1, __last1, __first2);
1657 }
1658 else
1659 {
1660 for (; __first1 != __last1 && __first2 != __last2;
1661 ++__first1, (void)++__first2)
1662 if (!(*__first1 == *__first2))
1663 return false;
1664 return __first1 == __last1 && __first2 == __last2;
1665 }
1666 }
1667
1668 // 4-iterator version of std::equal<It1, It2, BinaryPred> for use in C++11.
1669 template<typename _II1, typename _II2, typename _BinaryPredicate>
1670 _GLIBCXX20_CONSTEXPR
1671 inline bool
1672 __equal4(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2,
1673 _BinaryPredicate __binary_pred)
1674 {
1675 using _RATag = random_access_iterator_tag;
1676 using _Cat1 = decltype(std::__iter_concept_or_category<_II1>());
1677 using _Cat2 = decltype(std::__iter_concept_or_category<_II2>());
1678 using _RAIters = __and_<is_same<_Cat1, _RATag>, is_same<_Cat2, _RATag>>;
1679 if constexpr (_RAIters::value)
1680 {
1681 if ((__last1 - __first1) != (__last2 - __first2))
1682 return false;
1683 return _GLIBCXX_STD_A::equal(__first1, __last1, __first2,
1684 __binary_pred);
1685 }
1686 else
1687 {
1688 for (; __first1 != __last1 && __first2 != __last2;
1689 ++__first1, (void)++__first2)
1690 if (!bool(__binary_pred(*__first1, *__first2)))
1691 return false;
1692 return __first1 == __last1 && __first2 == __last2;
1693 }
1694 }
1695#pragma GCC diagnostic pop
1696#endif // C++11
1697
1698#ifdef __glibcxx_robust_nonmodifying_seq_ops // C++ >= 14
1699 /**
1700 * @brief Tests a range for element-wise equality.
1701 * @ingroup non_mutating_algorithms
1702 * @param __first1 An input iterator.
1703 * @param __last1 An input iterator.
1704 * @param __first2 An input iterator.
1705 * @param __last2 An input iterator.
1706 * @return A boolean true or false.
1707 *
1708 * This compares the elements of two ranges using @c == and returns true or
1709 * false depending on whether all of the corresponding elements of the
1710 * ranges are equal.
1711 */
1712 template<typename _II1, typename _II2>
1713 _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
1714 inline bool
1715 equal(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
1716 {
1717 // concept requirements
1718 __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1719 __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1720 __glibcxx_function_requires(_EqualOpConcept<
1721 typename iterator_traits<_II1>::value_type,
1722 typename iterator_traits<_II2>::value_type>)
1723 __glibcxx_requires_valid_range(__first1, __last1);
1724 __glibcxx_requires_valid_range(__first2, __last2);
1725
1726 return _GLIBCXX_STD_A::__equal4(__first1, __last1, __first2, __last2);
1727 }
1728
1729 /**
1730 * @brief Tests a range for element-wise equality.
1731 * @ingroup non_mutating_algorithms
1732 * @param __first1 An input iterator.
1733 * @param __last1 An input iterator.
1734 * @param __first2 An input iterator.
1735 * @param __last2 An input iterator.
1736 * @param __binary_pred A binary predicate @link functors
1737 * functor@endlink.
1738 * @return A boolean true or false.
1739 *
1740 * This compares the elements of two ranges using the binary_pred
1741 * parameter, and returns true or
1742 * false depending on whether all of the corresponding elements of the
1743 * ranges are equal.
1744 */
1745 template<typename _IIter1, typename _IIter2, typename _BinaryPredicate>
1746 _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
1747 inline bool
1748 equal(_IIter1 __first1, _IIter1 __last1,
1749 _IIter2 __first2, _IIter2 __last2, _BinaryPredicate __binary_pred)
1750 {
1751 // concept requirements
1752 __glibcxx_function_requires(_InputIteratorConcept<_IIter1>)
1753 __glibcxx_function_requires(_InputIteratorConcept<_IIter2>)
1754 __glibcxx_requires_valid_range(__first1, __last1);
1755 __glibcxx_requires_valid_range(__first2, __last2);
1756
1757 return _GLIBCXX_STD_A::__equal4(__first1, __last1, __first2, __last2,
1758 __binary_pred);
1759 }
1760#endif // __glibcxx_robust_nonmodifying_seq_ops
1761
1762 /**
1763 * @brief Performs @b dictionary comparison on ranges.
1764 * @ingroup sorting_algorithms
1765 * @param __first1 An input iterator.
1766 * @param __last1 An input iterator.
1767 * @param __first2 An input iterator.
1768 * @param __last2 An input iterator.
1769 * @return A boolean true or false.
1770 *
1771 * <em>Returns true if the sequence of elements defined by the range
1772 * [first1,last1) is lexicographically less than the sequence of elements
1773 * defined by the range [first2,last2). Returns false otherwise.</em>
1774 * (Quoted from [25.3.8]/1.) If the iterators are all character pointers,
1775 * then this is an inline call to @c memcmp.
1776 */
1777 template<typename _II1, typename _II2>
1778 _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
1779 inline bool
1780 lexicographical_compare(_II1 __first1, _II1 __last1,
1781 _II2 __first2, _II2 __last2)
1782 {
1783#ifdef _GLIBCXX_CONCEPT_CHECKS
1784 // concept requirements
1785 typedef typename iterator_traits<_II1>::value_type _ValueType1;
1786 typedef typename iterator_traits<_II2>::value_type _ValueType2;
1787#endif
1788 __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1789 __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1790 __glibcxx_function_requires(_LessThanOpConcept<_ValueType1, _ValueType2>)
1791 __glibcxx_function_requires(_LessThanOpConcept<_ValueType2, _ValueType1>)
1792 __glibcxx_requires_valid_range(__first1, __last1);
1793 __glibcxx_requires_valid_range(__first2, __last2);
1794
1795 return std::__lexicographical_compare_aux(__first1, __last1,
1796 __first2, __last2);
1797 }
1798
1799 /**
1800 * @brief Performs @b dictionary comparison on ranges.
1801 * @ingroup sorting_algorithms
1802 * @param __first1 An input iterator.
1803 * @param __last1 An input iterator.
1804 * @param __first2 An input iterator.
1805 * @param __last2 An input iterator.
1806 * @param __comp A @link comparison_functors comparison functor@endlink.
1807 * @return A boolean true or false.
1808 *
1809 * The same as the four-parameter @c lexicographical_compare, but uses the
1810 * comp parameter instead of @c <.
1811 */
1812 template<typename _II1, typename _II2, typename _Compare>
1813 _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
1814 inline bool
1815 lexicographical_compare(_II1 __first1, _II1 __last1,
1816 _II2 __first2, _II2 __last2, _Compare __comp)
1817 {
1818 // concept requirements
1819 __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1820 __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1821 __glibcxx_requires_valid_range(__first1, __last1);
1822 __glibcxx_requires_valid_range(__first2, __last2);
1823
1824 return std::__lexicographical_compare_impl
1825 (__first1, __last1, __first2, __last2, __comp);
1826 }
1827
1828#if __cpp_lib_three_way_comparison
1829 // Both iterators refer to contiguous ranges of unsigned narrow characters,
1830 // or std::byte, or big-endian unsigned integers, suitable for comparison
1831 // using memcmp.
1832 template<typename _Iter1, typename _Iter2>
1833 concept __memcmp_ordered_with
1834 = (__is_memcmp_ordered_with<iter_value_t<_Iter1>,
1835 iter_value_t<_Iter2>>::__value)
1836 && contiguous_iterator<_Iter1> && contiguous_iterator<_Iter2>;
1837
1838 // Return a struct with two members, initialized to the smaller of x and y
1839 // (or x if they compare equal) and the result of the comparison x <=> y.
1840 template<typename _Tp>
1841 constexpr auto
1842 __min_cmp(_Tp __x, _Tp __y)
1843 {
1844 struct _Res {
1845 _Tp _M_min;
1846 decltype(__x <=> __y) _M_cmp;
1847 };
1848 auto __c = __x <=> __y;
1849 if (__c > 0)
1850 return _Res{__y, __c};
1851 return _Res{__x, __c};
1852 }
1853
1854 /**
1855 * @brief Performs dictionary comparison on ranges.
1856 * @ingroup sorting_algorithms
1857 * @param __first1 An input iterator.
1858 * @param __last1 An input iterator.
1859 * @param __first2 An input iterator.
1860 * @param __last2 An input iterator.
1861 * @param __comp A @link comparison_functors comparison functor@endlink.
1862 * @return The comparison category that `__comp(*__first1, *__first2)`
1863 * returns.
1864 */
1865 template<typename _InputIter1, typename _InputIter2, typename _Comp>
1866 [[nodiscard]] constexpr auto
1867 lexicographical_compare_three_way(_InputIter1 __first1,
1868 _InputIter1 __last1,
1869 _InputIter2 __first2,
1870 _InputIter2 __last2,
1871 _Comp __comp)
1872 -> decltype(__comp(*__first1, *__first2))
1873 {
1874 // concept requirements
1875 __glibcxx_function_requires(_InputIteratorConcept<_InputIter1>)
1876 __glibcxx_function_requires(_InputIteratorConcept<_InputIter2>)
1877 __glibcxx_requires_valid_range(__first1, __last1);
1878 __glibcxx_requires_valid_range(__first2, __last2);
1879
1880 using _Cat = decltype(__comp(*__first1, *__first2));
1881 static_assert(same_as<common_comparison_category_t<_Cat>, _Cat>);
1882
1883 if (!std::__is_constant_evaluated())
1884 if constexpr (same_as<_Comp, __detail::_Synth3way>
1885 || same_as<_Comp, compare_three_way>)
1886 if constexpr (__memcmp_ordered_with<_InputIter1, _InputIter2>)
1887 {
1888 const auto [__len, __lencmp] = _GLIBCXX_STD_A::
1889 __min_cmp(__last1 - __first1, __last2 - __first2);
1890 if (__len)
1891 {
1892 const auto __blen = __len * sizeof(*__first1);
1893 const auto __c
1894 = __builtin_memcmp(&*__first1, &*__first2, __blen) <=> 0;
1895 if (__c != 0)
1896 return __c;
1897 }
1898 return __lencmp;
1899 }
1900
1901 while (__first1 != __last1)
1902 {
1903 if (__first2 == __last2)
1904 return strong_ordering::greater;
1905 if (auto __cmp = __comp(*__first1, *__first2); __cmp != 0)
1906 return __cmp;
1907 ++__first1;
1908 ++__first2;
1909 }
1910 return (__first2 == __last2) <=> true; // See PR 94006
1911 }
1912
1913 template<typename _InputIter1, typename _InputIter2>
1914 constexpr auto
1915 lexicographical_compare_three_way(_InputIter1 __first1,
1916 _InputIter1 __last1,
1917 _InputIter2 __first2,
1918 _InputIter2 __last2)
1919 {
1920 return _GLIBCXX_STD_A::
1921 lexicographical_compare_three_way(__first1, __last1, __first2, __last2,
1922 compare_three_way{});
1923 }
1924#endif // three_way_comparison
1925
1926 template<typename _InputIterator1, typename _InputIterator2,
1927 typename _BinaryPredicate>
1928 _GLIBCXX20_CONSTEXPR
1929 pair<_InputIterator1, _InputIterator2>
1930 __mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1931 _InputIterator2 __first2, _BinaryPredicate __binary_pred)
1932 {
1933 while (__first1 != __last1 && __binary_pred(*__first1, *__first2))
1934 {
1935 ++__first1;
1936 ++__first2;
1937 }
1938 return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
1939 }
1940
1941 /**
1942 * @brief Finds the places in ranges which don't match.
1943 * @ingroup non_mutating_algorithms
1944 * @param __first1 An input iterator.
1945 * @param __last1 An input iterator.
1946 * @param __first2 An input iterator.
1947 * @return A pair of iterators pointing to the first mismatch.
1948 *
1949 * This compares the elements of two ranges using @c == and returns a pair
1950 * of iterators. The first iterator points into the first range, the
1951 * second iterator points into the second range, and the elements pointed
1952 * to by the iterators are not equal.
1953 */
1954 template<typename _InputIterator1, typename _InputIterator2>
1955 _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
1956 inline pair<_InputIterator1, _InputIterator2>
1957 mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1958 _InputIterator2 __first2)
1959 {
1960 // concept requirements
1961 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
1962 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
1963 __glibcxx_function_requires(_EqualOpConcept<
1964 typename iterator_traits<_InputIterator1>::value_type,
1965 typename iterator_traits<_InputIterator2>::value_type>)
1966 __glibcxx_requires_valid_range(__first1, __last1);
1967
1968 return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2,
1969 __gnu_cxx::__ops::equal_to());
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 __binary_pred A binary predicate @link functors
1979 * functor@endlink.
1980 * @return A pair of iterators pointing to the first mismatch.
1981 *
1982 * This compares the elements of two ranges using the binary_pred
1983 * parameter, 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 typename _BinaryPredicate>
1990 _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
1991 inline pair<_InputIterator1, _InputIterator2>
1992 mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1993 _InputIterator2 __first2, _BinaryPredicate __binary_pred)
1994 {
1995 // concept requirements
1996 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
1997 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
1998 __glibcxx_requires_valid_range(__first1, __last1);
1999
2000 return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2,
2001 __binary_pred);
2002 }
2003
2004#if __glibcxx_robust_nonmodifying_seq_ops // C++ >= 14
2005 template<typename _InputIterator1, typename _InputIterator2,
2006 typename _BinaryPredicate>
2007 _GLIBCXX20_CONSTEXPR
2008 pair<_InputIterator1, _InputIterator2>
2009 __mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
2010 _InputIterator2 __first2, _InputIterator2 __last2,
2011 _BinaryPredicate __binary_pred)
2012 {
2013 while (__first1 != __last1 && __first2 != __last2
2014 && __binary_pred(*__first1, *__first2))
2015 {
2016 ++__first1;
2017 ++__first2;
2018 }
2019 return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
2020 }
2021
2022 /**
2023 * @brief Finds the places in ranges which don't match.
2024 * @ingroup non_mutating_algorithms
2025 * @param __first1 An input iterator.
2026 * @param __last1 An input iterator.
2027 * @param __first2 An input iterator.
2028 * @param __last2 An input iterator.
2029 * @return A pair of iterators pointing to the first mismatch.
2030 *
2031 * This compares the elements of two ranges using @c == and returns a pair
2032 * of iterators. The first iterator points into the first range, the
2033 * second iterator points into the second range, and the elements pointed
2034 * to by the iterators are not equal.
2035 */
2036 template<typename _InputIterator1, typename _InputIterator2>
2037 _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
2038 inline pair<_InputIterator1, _InputIterator2>
2039 mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
2040 _InputIterator2 __first2, _InputIterator2 __last2)
2041 {
2042 // concept requirements
2043 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
2044 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
2045 __glibcxx_function_requires(_EqualOpConcept<
2046 typename iterator_traits<_InputIterator1>::value_type,
2047 typename iterator_traits<_InputIterator2>::value_type>)
2048 __glibcxx_requires_valid_range(__first1, __last1);
2049 __glibcxx_requires_valid_range(__first2, __last2);
2050
2051 return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2, __last2,
2052 __gnu_cxx::__ops::equal_to());
2053 }
2054
2055 /**
2056 * @brief Finds the places in ranges which don't match.
2057 * @ingroup non_mutating_algorithms
2058 * @param __first1 An input iterator.
2059 * @param __last1 An input iterator.
2060 * @param __first2 An input iterator.
2061 * @param __last2 An input iterator.
2062 * @param __binary_pred A binary predicate @link functors
2063 * functor@endlink.
2064 * @return A pair of iterators pointing to the first mismatch.
2065 *
2066 * This compares the elements of two ranges using the binary_pred
2067 * parameter, and returns a pair
2068 * of iterators. The first iterator points into the first range, the
2069 * second iterator points into the second range, and the elements pointed
2070 * to by the iterators are not equal.
2071 */
2072 template<typename _InputIterator1, typename _InputIterator2,
2073 typename _BinaryPredicate>
2074 _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
2075 inline pair<_InputIterator1, _InputIterator2>
2076 mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
2077 _InputIterator2 __first2, _InputIterator2 __last2,
2078 _BinaryPredicate __binary_pred)
2079 {
2080 // concept requirements
2081 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
2082 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
2083 __glibcxx_requires_valid_range(__first1, __last1);
2084 __glibcxx_requires_valid_range(__first2, __last2);
2085
2086 return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2, __last2,
2087 __binary_pred);
2088 }
2089#endif // __glibcxx_robust_nonmodifying_seq_ops
2090
2091_GLIBCXX_END_NAMESPACE_ALGO
2092
2093 // Implementation of std::find_if, also used in std::remove_if and others.
2094 template<typename _Iterator, typename _Predicate>
2095 _GLIBCXX20_CONSTEXPR
2096 inline _Iterator
2097 __find_if(_Iterator __first, _Iterator __last, _Predicate __pred)
2098 {
2099#pragma GCC unroll 4
2100 while (__first != __last && !__pred(*__first))
2101 ++__first;
2102 return __first;
2103 }
2104
2105 template<typename _InputIterator, typename _Predicate>
2106 _GLIBCXX20_CONSTEXPR
2107 typename iterator_traits<_InputIterator>::difference_type
2108 __count_if(_InputIterator __first, _InputIterator __last, _Predicate __pred)
2109 {
2110 typename iterator_traits<_InputIterator>::difference_type __n = 0;
2111 for (; __first != __last; ++__first)
2112 if (__pred(*__first))
2113 ++__n;
2114 return __n;
2115 }
2116
2117 template<typename _ForwardIterator, typename _Predicate>
2118 _GLIBCXX20_CONSTEXPR
2119 _ForwardIterator
2120 __remove_if(_ForwardIterator __first, _ForwardIterator __last,
2121 _Predicate __pred)
2122 {
2123 __first = std::__find_if(__first, __last, __pred);
2124 if (__first == __last)
2125 return __first;
2126 _ForwardIterator __result = __first;
2127 ++__first;
2128 for (; __first != __last; ++__first)
2129 if (!__pred(*__first))
2130 {
2131 *__result = _GLIBCXX_MOVE(*__first);
2132 ++__result;
2133 }
2134 return __result;
2135 }
2136
2137 template<typename _ForwardIterator1, typename _ForwardIterator2,
2138 typename _BinaryPredicate>
2139 _GLIBCXX20_CONSTEXPR
2140 _ForwardIterator1
2141 __search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
2142 _ForwardIterator2 __first2, _ForwardIterator2 __last2,
2143 _BinaryPredicate __predicate)
2144 {
2145 // Test for empty ranges
2146 if (__first1 == __last1 || __first2 == __last2)
2147 return __first1;
2148
2149 __decltype(*__first2) __first2_val(*__first2);
2150 __decltype(__gnu_cxx::__ops::bind2nd(__predicate, __first2_val))
2151 __match_first = __gnu_cxx::__ops::bind2nd(__predicate, __first2_val);
2152
2153 // Test for a pattern of length 1.
2154 _ForwardIterator2 __p1(__first2);
2155 if (++__p1 == __last2)
2156 return std::__find_if(__first1, __last1, __match_first);
2157
2158 // General case.
2159 _ForwardIterator1 __current = __first1;
2160
2161 for (;;)
2162 {
2163 __first1 = std::__find_if(__first1, __last1, __match_first);
2164
2165 if (__first1 == __last1)
2166 return __last1;
2167
2168 _ForwardIterator2 __p = __p1;
2169 __current = __first1;
2170 if (++__current == __last1)
2171 return __last1;
2172
2173 while (__predicate(*__current, *__p))
2174 {
2175 if (++__p == __last2)
2176 return __first1;
2177 if (++__current == __last1)
2178 return __last1;
2179 }
2180 ++__first1;
2181 }
2182 return __first1;
2183 }
2184#undef __match_first
2185
2186#if __cplusplus >= 201103L
2187 template<typename _ForwardIterator1, typename _ForwardIterator2,
2188 typename _BinaryPredicate>
2189 _GLIBCXX20_CONSTEXPR
2190 bool
2191 __is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
2192 _ForwardIterator2 __first2, _BinaryPredicate __pred)
2193 {
2194 // Efficiently compare identical prefixes: O(N) if sequences
2195 // have the same elements in the same order.
2196 for (; __first1 != __last1; ++__first1, (void)++__first2)
2197 if (!__pred(*__first1, *__first2))
2198 break;
2199
2200 if (__first1 == __last1)
2201 return true;
2202
2203 // Establish __last2 assuming equal ranges by iterating over the
2204 // rest of the list.
2205 _ForwardIterator2 __last2 = __first2;
2206 std::advance(__last2, std::distance(__first1, __last1));
2207 for (_ForwardIterator1 __scan = __first1; __scan != __last1; ++__scan)
2208 {
2209 auto&& __scan_val = *__scan;
2210 auto __scaneq = __gnu_cxx::__ops::bind1st(__pred, __scan_val);
2211 if (__scan != std::__find_if(__first1, __scan, __scaneq))
2212 continue; // We've seen this one before.
2213
2214 auto __matches = std::__count_if(__first2, __last2, __scaneq);
2215 if (0 == __matches
2216 || std::__count_if(__scan, __last1, __scaneq) != __matches)
2217 return false;
2218 }
2219 return true;
2220 }
2221
2222 /**
2223 * @brief Checks whether a permutation of the second sequence is equal
2224 * to the first sequence.
2225 * @ingroup non_mutating_algorithms
2226 * @param __first1 Start of first range.
2227 * @param __last1 End of first range.
2228 * @param __first2 Start of second range.
2229 * @return true if there exists a permutation of the elements in the range
2230 * [__first2, __first2 + (__last1 - __first1)), beginning with
2231 * ForwardIterator2 begin, such that equal(__first1, __last1, begin)
2232 * returns true; otherwise, returns false.
2233 */
2234 template<typename _ForwardIterator1, typename _ForwardIterator2>
2235 _GLIBCXX20_CONSTEXPR
2236 inline bool
2237 is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
2238 _ForwardIterator2 __first2)
2239 {
2240 // concept requirements
2241 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
2242 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
2243 __glibcxx_function_requires(_EqualOpConcept<
2244 typename iterator_traits<_ForwardIterator1>::value_type,
2245 typename iterator_traits<_ForwardIterator2>::value_type>)
2246 __glibcxx_requires_valid_range(__first1, __last1);
2247
2248 return std::__is_permutation(__first1, __last1, __first2,
2249 __gnu_cxx::__ops::equal_to());
2250 }
2251#endif // C++11
2252
2253_GLIBCXX_BEGIN_NAMESPACE_ALGO
2254
2255 /**
2256 * @brief Search a sequence for a matching sub-sequence using a predicate.
2257 * @ingroup non_mutating_algorithms
2258 * @param __first1 A forward iterator.
2259 * @param __last1 A forward iterator.
2260 * @param __first2 A forward iterator.
2261 * @param __last2 A forward iterator.
2262 * @param __predicate A binary predicate.
2263 * @return The first iterator @c i in the range
2264 * @p [__first1,__last1-(__last2-__first2)) such that
2265 * @p __predicate(*(i+N),*(__first2+N)) is true for each @c N in the range
2266 * @p [0,__last2-__first2), or @p __last1 if no such iterator exists.
2267 *
2268 * Searches the range @p [__first1,__last1) for a sub-sequence that
2269 * compares equal value-by-value with the sequence given by @p
2270 * [__first2,__last2), using @p __predicate to determine equality,
2271 * and returns an iterator to the first element of the
2272 * sub-sequence, or @p __last1 if no such iterator exists.
2273 *
2274 * @see search(_ForwardIter1, _ForwardIter1, _ForwardIter2, _ForwardIter2)
2275 */
2276 template<typename _ForwardIterator1, typename _ForwardIterator2,
2277 typename _BinaryPredicate>
2278 _GLIBCXX20_CONSTEXPR
2279 inline _ForwardIterator1
2280 search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
2281 _ForwardIterator2 __first2, _ForwardIterator2 __last2,
2282 _BinaryPredicate __predicate)
2283 {
2284 // concept requirements
2285 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
2286 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
2287 __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
2288 typename iterator_traits<_ForwardIterator1>::value_type,
2289 typename iterator_traits<_ForwardIterator2>::value_type>)
2290 __glibcxx_requires_valid_range(__first1, __last1);
2291 __glibcxx_requires_valid_range(__first2, __last2);
2292
2293 return std::__search(__first1, __last1, __first2, __last2, __predicate);
2294 }
2295
2296_GLIBCXX_END_NAMESPACE_ALGO
2297_GLIBCXX_END_NAMESPACE_VERSION
2298} // namespace std
2299
2300// NB: This file is included within many other C++ includes, as a way
2301// of getting the base algorithms. So, make sure that parallel bits
2302// come in too if requested.
2303#ifdef _GLIBCXX_PARALLEL
2304# include <parallel/algobase.h>
2305#endif
2306
2307#endif
algobase.h
Parallel STL function calls corresponding to the stl_algobase.h header. The functions defined here ma...
std::to_address
constexpr _Tp * to_address(_Tp *__ptr) noexcept
Obtain address referenced by a pointer to an object.
Definition ptr_traits.h:232
std::make_unsigned_t
typename make_unsigned< _Tp >::type make_unsigned_t
Alias template for make_unsigned.
Definition type_traits:2246
std::pair::pair
pair(_T1, _T2) -> pair< _T1, _T2 >
Two pairs are equal iff their members are equal.
std::move
constexpr std::remove_reference< _Tp >::type && move(_Tp &&__t) noexcept
Convert a value to an rvalue.
Definition move.h:138
std::move_backward
constexpr _BI2 move_backward(_BI1 __first, _BI1 __last, _BI2 __result)
Moves the range [first,last) into result.
Definition stl_algobase.h:871
std::lexicographical_compare_three_way
constexpr auto lexicographical_compare_three_way(_InputIter1 __first1, _InputIter1 __last1, _InputIter2 __first2, _InputIter2 __last2, _Comp __comp) -> decltype(__comp(*__first1, *__first2))
Performs dictionary comparison on ranges.
Definition stl_algobase.h:1867
std::max
constexpr const _Tp & max(const _Tp &, const _Tp &)
This does what you think it does.
Definition stl_algobase.h:256
std::min
constexpr const _Tp & min(const _Tp &, const _Tp &)
This does what you think it does.
Definition stl_algobase.h:232
std::__iterator_category
constexpr iterator_traits< _Iter >::iterator_category __iterator_category(const _Iter &)
Definition stl_iterator_base_types.h:241
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:172
std::__lg
constexpr _Tp __lg(_Tp __n)
This is a helper function for the sort routines and for random.tcc.
Definition stl_algobase.h:1558
std::advance
constexpr void advance(_InputIterator &__i, _Distance __n)
A generalization of pointer arithmetic.
Definition stl_iterator_base_funcs.h:261
std::istreambuf_iterator
Provides input iterator semantics for streambufs.
Definition streambuf_iterator.h:59
std::is_integral
is_integral
Definition type_traits:541
std::char_traits
Basis for explicit traits specializations.
Definition char_traits.h:329
std::iterator_traits
Traits class for iterators.
Definition stl_iterator_base_types.h:180
std::pair
Struct holding two objects (or references) of arbitrary type.
Definition stl_pair.h:307
std::random_access_iterator_tag
Random-access iterators support a superset of bidirectional iterator operations.
Definition stl_iterator_base_types.h:109
std::same_as
[concept.same], concept same_as
Definition concepts:65