libstdc++
stl_algobase.h
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1// Core algorithmic facilities -*- C++ -*-
2
3// Copyright (C) 2001-2025 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>
62#include <ext/type_traits.h>
63#include <ext/numeric_traits.h>
64#include <bits/stl_pair.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 >= 201402L
76# include <bit> // std::__bit_width
77#endif
78#if __cplusplus >= 202002L
79# include <compare>
80# include <bits/ptr_traits.h> // std::to_address
81#endif
82
83namespace std _GLIBCXX_VISIBILITY(default)
84{
85_GLIBCXX_BEGIN_NAMESPACE_VERSION
86
87 /*
88 * A constexpr wrapper for __builtin_memcmp.
89 * @param __num The number of elements of type _Tp (not bytes).
90 */
91 template<typename _Tp, typename _Up>
92 _GLIBCXX14_CONSTEXPR
93 inline int
94 __memcmp(const _Tp* __first1, const _Up* __first2, size_t __num)
95 {
96#if __cplusplus >= 201103L
97 static_assert(sizeof(_Tp) == sizeof(_Up), "can be compared with memcmp");
98#endif
99#ifdef __cpp_lib_is_constant_evaluated
101 {
102 for(; __num > 0; ++__first1, ++__first2, --__num)
103 if (*__first1 != *__first2)
104 return *__first1 < *__first2 ? -1 : 1;
105 return 0;
106 }
107 else
108#endif
109 return __builtin_memcmp(__first1, __first2, sizeof(_Tp) * __num);
110 }
111
112#if __cplusplus < 201103L
113 // See http://gcc.gnu.org/ml/libstdc++/2004-08/msg00167.html: in a
114 // nutshell, we are partially implementing the resolution of DR 187,
115 // when it's safe, i.e., the value_types are equal.
116 template<bool _BoolType>
117 struct __iter_swap
118 {
119 template<typename _ForwardIterator1, typename _ForwardIterator2>
120 static void
121 iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
122 {
123 typedef typename iterator_traits<_ForwardIterator1>::value_type
124 _ValueType1;
125 _ValueType1 __tmp = *__a;
126 *__a = *__b;
127 *__b = __tmp;
128 }
129 };
130
131 template<>
132 struct __iter_swap<true>
133 {
134 template<typename _ForwardIterator1, typename _ForwardIterator2>
135 static void
136 iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
137 {
138 swap(*__a, *__b);
139 }
140 };
141#endif // C++03
142
143 /**
144 * @brief Swaps the contents of two iterators.
145 * @ingroup mutating_algorithms
146 * @param __a An iterator.
147 * @param __b Another iterator.
148 * @return Nothing.
149 *
150 * This function swaps the values pointed to by two iterators, not the
151 * iterators themselves.
152 */
153 template<typename _ForwardIterator1, typename _ForwardIterator2>
154 _GLIBCXX20_CONSTEXPR
155 inline void
157 {
158 // concept requirements
159 __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
161 __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
163
164#if __cplusplus < 201103L
169
170 __glibcxx_function_requires(_ConvertibleConcept<_ValueType1,
172 __glibcxx_function_requires(_ConvertibleConcept<_ValueType2,
174
180 && __are_same<_ValueType1&, _ReferenceType1>::__value
181 && __are_same<_ValueType2&, _ReferenceType2>::__value>::
182 iter_swap(__a, __b);
183#else
184 // _GLIBCXX_RESOLVE_LIB_DEFECTS
185 // 187. iter_swap underspecified
186 swap(*__a, *__b);
187#endif
188 }
189
190 /**
191 * @brief Swap the elements of two sequences.
192 * @ingroup mutating_algorithms
193 * @param __first1 A forward iterator.
194 * @param __last1 A forward iterator.
195 * @param __first2 A forward iterator.
196 * @return An iterator equal to @p first2+(last1-first1).
197 *
198 * Swaps each element in the range @p [first1,last1) with the
199 * corresponding element in the range @p [first2,(last1-first1)).
200 * The ranges must not overlap.
201 */
202 template<typename _ForwardIterator1, typename _ForwardIterator2>
203 _GLIBCXX20_CONSTEXPR
204 _ForwardIterator2
207 {
208 // concept requirements
209 __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
211 __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
213 __glibcxx_requires_valid_range(__first1, __last1);
214
215 for (; __first1 != __last1; ++__first1, (void)++__first2)
216 std::iter_swap(__first1, __first2);
217 return __first2;
218 }
219
220 /**
221 * @brief This does what you think it does.
222 * @ingroup sorting_algorithms
223 * @param __a A thing of arbitrary type.
224 * @param __b Another thing of arbitrary type.
225 * @return The lesser of the parameters.
226 *
227 * This is the simple classic generic implementation. It will work on
228 * temporary expressions, since they are only evaluated once, unlike a
229 * preprocessor macro.
230 */
231 template<typename _Tp>
232 _GLIBCXX_NODISCARD _GLIBCXX14_CONSTEXPR
233 inline const _Tp&
234 min(const _Tp& __a, const _Tp& __b)
235 {
236 // concept requirements
237 __glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
238 //return __b < __a ? __b : __a;
239 if (__b < __a)
240 return __b;
241 return __a;
242 }
243
244 /**
245 * @brief This does what you think it does.
246 * @ingroup sorting_algorithms
247 * @param __a A thing of arbitrary type.
248 * @param __b Another thing of arbitrary type.
249 * @return The greater of the parameters.
250 *
251 * This is the simple classic generic implementation. It will work on
252 * temporary expressions, since they are only evaluated once, unlike a
253 * preprocessor macro.
254 */
255 template<typename _Tp>
256 _GLIBCXX_NODISCARD _GLIBCXX14_CONSTEXPR
257 inline const _Tp&
258 max(const _Tp& __a, const _Tp& __b)
259 {
260 // concept requirements
261 __glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
262 //return __a < __b ? __b : __a;
263 if (__a < __b)
264 return __b;
265 return __a;
266 }
267
268 /**
269 * @brief This does what you think it does.
270 * @ingroup sorting_algorithms
271 * @param __a A thing of arbitrary type.
272 * @param __b Another thing of arbitrary type.
273 * @param __comp A @link comparison_functors comparison functor@endlink.
274 * @return The lesser of the parameters.
275 *
276 * This will work on temporary expressions, since they are only evaluated
277 * once, unlike a preprocessor macro.
278 */
279 template<typename _Tp, typename _Compare>
280 _GLIBCXX_NODISCARD _GLIBCXX14_CONSTEXPR
281 inline const _Tp&
282 min(const _Tp& __a, const _Tp& __b, _Compare __comp)
283 {
284 //return __comp(__b, __a) ? __b : __a;
285 if (__comp(__b, __a))
286 return __b;
287 return __a;
288 }
289
290 /**
291 * @brief This does what you think it does.
292 * @ingroup sorting_algorithms
293 * @param __a A thing of arbitrary type.
294 * @param __b Another thing of arbitrary type.
295 * @param __comp A @link comparison_functors comparison functor@endlink.
296 * @return The greater of the parameters.
297 *
298 * This will work on temporary expressions, since they are only evaluated
299 * once, unlike a preprocessor macro.
300 */
301 template<typename _Tp, typename _Compare>
302 _GLIBCXX_NODISCARD _GLIBCXX14_CONSTEXPR
303 inline const _Tp&
304 max(const _Tp& __a, const _Tp& __b, _Compare __comp)
305 {
306 //return __comp(__a, __b) ? __b : __a;
307 if (__comp(__a, __b))
308 return __b;
309 return __a;
310 }
311
312_GLIBCXX_BEGIN_NAMESPACE_CONTAINER
313
314 template<typename _Tp, typename _Ref, typename _Ptr>
315 struct _Deque_iterator;
316
317 struct _Bit_iterator;
318
319_GLIBCXX_END_NAMESPACE_CONTAINER
320
321#if _GLIBCXX_HOSTED
322 // Helpers for streambuf iterators (either istream or ostream).
323 // NB: avoid including <iosfwd>, relatively large.
324 template<typename _CharT>
325 struct char_traits;
326
327 template<typename _CharT, typename _Traits>
328 class istreambuf_iterator;
329
330 template<typename _CharT, typename _Traits>
331 class ostreambuf_iterator;
332
333 template<bool _IsMove, typename _CharT>
334 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
335 ostreambuf_iterator<_CharT, char_traits<_CharT> > >::__type
336 __copy_move_a2(_CharT*, _CharT*,
337 ostreambuf_iterator<_CharT, char_traits<_CharT> >);
338
339 template<bool _IsMove, typename _CharT>
340 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
341 ostreambuf_iterator<_CharT, char_traits<_CharT> > >::__type
342 __copy_move_a2(const _CharT*, const _CharT*,
343 ostreambuf_iterator<_CharT, char_traits<_CharT> >);
344
345 template<bool _IsMove, typename _CharT>
346 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
347 _CharT*>::__type
348 __copy_move_a2(istreambuf_iterator<_CharT, char_traits<_CharT> >,
349 istreambuf_iterator<_CharT, char_traits<_CharT> >, _CharT*);
350
351 template<bool _IsMove, typename _CharT>
352 typename __gnu_cxx::__enable_if<
353 __is_char<_CharT>::__value,
354 _GLIBCXX_STD_C::_Deque_iterator<_CharT, _CharT&, _CharT*> >::__type
355 __copy_move_a2(
356 istreambuf_iterator<_CharT, char_traits<_CharT> >,
357 istreambuf_iterator<_CharT, char_traits<_CharT> >,
358 _GLIBCXX_STD_C::_Deque_iterator<_CharT, _CharT&, _CharT*>);
359#endif // HOSTED
360
361#if __cpp_lib_concepts
362 template<typename _OutIter, typename _InIter, typename _Sent = _InIter>
363 concept __memcpyable_iterators
364 = contiguous_iterator<_OutIter> && contiguous_iterator<_InIter>
365 && sized_sentinel_for<_Sent, _InIter>
366 && requires (_OutIter __o, _InIter __i) {
367 requires !!__memcpyable<decltype(std::to_address(__o)),
368 decltype(std::to_address(__i))>::__value;
369 };
370#endif
371
372#if __cplusplus < 201103L
373 // Used by __copy_move_a2, __copy_n_a and __copy_move_backward_a2 to
374 // get raw pointers so that calls to __builtin_memmove will compile,
375 // because C++98 can't use 'if constexpr' so statements that use memmove
376 // with pointer arguments need to also compile for arbitrary iterator types.
377 template<typename _Iter> __attribute__((__always_inline__))
378 inline void* __ptr_or_null(_Iter) { return 0; }
379 template<typename _Tp> __attribute__((__always_inline__))
380 inline void* __ptr_or_null(_Tp* __p) { return (void*)__p; }
381# define _GLIBCXX_TO_ADDR(P) std::__ptr_or_null(P)
382 // Used to advance output iterators (std::advance requires InputIterator).
383 template<typename _Iter> __attribute__((__always_inline__))
384 inline void __ptr_advance(_Iter&, ptrdiff_t) { }
385 template<typename _Tp> __attribute__((__always_inline__))
386 inline void __ptr_advance(_Tp*& __p, ptrdiff_t __n) { __p += __n; }
387# define _GLIBCXX_ADVANCE(P, N) std::__ptr_advance(P, N)
388#else
389 // For C++11 mode the __builtin_memmove calls are guarded by 'if constexpr'
390 // so we know the iterators used with memmove are guaranteed to be pointers.
391# define _GLIBCXX_TO_ADDR(P) P
392# define _GLIBCXX_ADVANCE(P, N) P += N
393#endif
394
395#pragma GCC diagnostic push
396#pragma GCC diagnostic ignored "-Wc++17-extensions"
397 template<bool _IsMove, typename _OutIter, typename _InIter>
398 __attribute__((__always_inline__)) _GLIBCXX20_CONSTEXPR
399 inline void
400 __assign_one(_OutIter& __out, _InIter& __in)
401 {
402#if __cplusplus >= 201103L
403 if constexpr (_IsMove)
404 *__out = std::move(*__in);
405 else
406#endif
407 *__out = *__in;
408 }
409
410 template<bool _IsMove, typename _InIter, typename _Sent, typename _OutIter>
411 _GLIBCXX20_CONSTEXPR
412 inline _OutIter
413 __copy_move_a2(_InIter __first, _Sent __last, _OutIter __result)
414 {
415 typedef __decltype(*__first) _InRef;
416 typedef __decltype(*__result) _OutRef;
417 if _GLIBCXX_CONSTEXPR (!__is_trivially_assignable(_OutRef, _InRef))
418 { } /* Skip the optimizations and use the loop at the end. */
419 else if (std::__is_constant_evaluated())
420 { } /* Skip the optimizations and use the loop at the end. */
421 else if _GLIBCXX_CONSTEXPR (__memcpyable<_OutIter, _InIter>::__value)
422 {
423 ptrdiff_t __n = std::distance(__first, __last);
424 if (__builtin_expect(__n > 1, true))
425 {
426 __builtin_memmove(_GLIBCXX_TO_ADDR(__result),
427 _GLIBCXX_TO_ADDR(__first),
428 __n * sizeof(*__first));
429 _GLIBCXX_ADVANCE(__result, __n);
430 }
431 else if (__n == 1)
432 {
433 std::__assign_one<_IsMove>(__result, __first);
434 ++__result;
435 }
436 return __result;
437 }
438#if __cpp_lib_concepts
439 else if constexpr (__memcpyable_iterators<_OutIter, _InIter, _Sent>)
440 {
441 if (auto __n = __last - __first; __n > 1) [[likely]]
442 {
443 void* __dest = std::to_address(__result);
444 const void* __src = std::to_address(__first);
445 size_t __nbytes = __n * sizeof(iter_value_t<_InIter>);
446 // Advance the iterators and convert to pointers first.
447 // This gives the iterators a chance to do bounds checking.
448 (void) std::to_address(__result += __n);
449 (void) std::to_address(__first += __n);
450 __builtin_memmove(__dest, __src, __nbytes);
451 }
452 else if (__n == 1)
453 {
454 std::__assign_one<_IsMove>(__result, __first);
455 ++__result;
456 }
457 return __result;
458 }
459#endif
460
461 for (; __first != __last; ++__result, (void)++__first)
462 std::__assign_one<_IsMove>(__result, __first);
463 return __result;
464 }
465#pragma GCC diagnostic pop
466
467 template<bool _IsMove,
468 typename _Tp, typename _Ref, typename _Ptr, typename _OI>
469 _OI
470 __copy_move_a1(_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
471 _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
472 _OI);
473
474 template<bool _IsMove,
475 typename _ITp, typename _IRef, typename _IPtr, typename _OTp>
476 _GLIBCXX_STD_C::_Deque_iterator<_OTp, _OTp&, _OTp*>
477 __copy_move_a1(_GLIBCXX_STD_C::_Deque_iterator<_ITp, _IRef, _IPtr>,
478 _GLIBCXX_STD_C::_Deque_iterator<_ITp, _IRef, _IPtr>,
479 _GLIBCXX_STD_C::_Deque_iterator<_OTp, _OTp&, _OTp*>);
480
481 template<bool _IsMove, typename _II, typename _Tp>
482 typename __gnu_cxx::__enable_if<
483 __is_random_access_iter<_II>::__value,
484 _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*> >::__type
485 __copy_move_a1(_II, _II, _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*>);
486
487 template<bool _IsMove, typename _II, typename _OI>
488 __attribute__((__always_inline__))
489 _GLIBCXX20_CONSTEXPR
490 inline _OI
491 __copy_move_a1(_II __first, _II __last, _OI __result)
492 { return std::__copy_move_a2<_IsMove>(__first, __last, __result); }
493
494 template<bool _IsMove, typename _II, typename _OI>
495 __attribute__((__always_inline__))
496 _GLIBCXX20_CONSTEXPR
497 inline _OI
498 __copy_move_a(_II __first, _II __last, _OI __result)
499 {
500 return std::__niter_wrap(__result,
501 std::__copy_move_a1<_IsMove>(std::__niter_base(__first),
502 std::__niter_base(__last),
503 std::__niter_base(__result)));
504 }
505
506 template<bool _IsMove,
507 typename _Ite, typename _Seq, typename _Cat, typename _OI>
508 _GLIBCXX20_CONSTEXPR
509 _OI
510 __copy_move_a(const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
511 const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
512 _OI);
513
514 template<bool _IsMove,
515 typename _II, typename _Ite, typename _Seq, typename _Cat>
516 _GLIBCXX20_CONSTEXPR
518 __copy_move_a(_II, _II,
519 const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&);
520
521 template<bool _IsMove,
522 typename _IIte, typename _ISeq, typename _ICat,
523 typename _OIte, typename _OSeq, typename _OCat>
524 _GLIBCXX20_CONSTEXPR
525 ::__gnu_debug::_Safe_iterator<_OIte, _OSeq, _OCat>
526 __copy_move_a(const ::__gnu_debug::_Safe_iterator<_IIte, _ISeq, _ICat>&,
527 const ::__gnu_debug::_Safe_iterator<_IIte, _ISeq, _ICat>&,
528 const ::__gnu_debug::_Safe_iterator<_OIte, _OSeq, _OCat>&);
529
530#pragma GCC diagnostic push
531#pragma GCC diagnostic ignored "-Wc++17-extensions" // for if-constexpr
532 template<typename _InputIterator, typename _Size, typename _OutputIterator>
533 _GLIBCXX20_CONSTEXPR
534 _OutputIterator
535 __copy_n_a(_InputIterator __first, _Size __n, _OutputIterator __result,
536 bool)
537 {
538 typedef __decltype(*__first) _InRef;
539 typedef __decltype(*__result) _OutRef;
540 if _GLIBCXX_CONSTEXPR (!__is_trivially_assignable(_OutRef, _InRef))
541 { } /* Skip the optimizations and use the loop at the end. */
542#ifdef __cpp_lib_is_constant_evaluated
544 { } /* Skip the optimizations and use the loop at the end. */
545#endif
546 else if _GLIBCXX_CONSTEXPR (__memcpyable<_OutputIterator,
547 _InputIterator>::__value)
548 {
549 if (__builtin_expect(__n > 1, true))
550 {
551 __builtin_memmove(_GLIBCXX_TO_ADDR(__result),
552 _GLIBCXX_TO_ADDR(__first),
553 __n * sizeof(*__first));
554 _GLIBCXX_ADVANCE(__result, __n);
555 }
556 else if (__n == 1)
557 *__result++ = *__first;
558 return __result;
559 }
560#if __cpp_lib_concepts
561 else if constexpr (__memcpyable_iterators<_OutputIterator,
562 _InputIterator>)
563 {
564 if (__n > 1) [[likely]]
565 {
566 void* __dest = std::to_address(__result);
567 const void* __src = std::to_address(__first);
568 size_t __nbytes = __n * sizeof(iter_value_t<_InputIterator>);
569 // Advance the iterators and convert to pointers first.
570 // This gives the iterators a chance to do bounds checking.
571 (void) std::to_address(__result += __n);
572 (void) std::to_address(__first += __n);
573 __builtin_memmove(__dest, __src, __nbytes);
574 }
575 else if (__n == 1)
576 *__result++ = *__first;
577 return __result;
578 }
579#endif
580
581 if (__n > 0)
582 {
583 while (true)
584 {
585 *__result = *__first;
586 ++__result;
587 if (--__n > 0)
588 ++__first;
589 else
590 break;
591 }
592 }
593 return __result;
594 }
595#pragma GCC diagnostic pop
596
597#if _GLIBCXX_HOSTED
598 template<typename _CharT, typename _Size>
599 typename __gnu_cxx::__enable_if<
600 __is_char<_CharT>::__value, _CharT*>::__type
601 __copy_n_a(istreambuf_iterator<_CharT, char_traits<_CharT> >,
602 _Size, _CharT*, bool);
603
604 template<typename _CharT, typename _Size>
605 typename __gnu_cxx::__enable_if<
606 __is_char<_CharT>::__value,
607 _GLIBCXX_STD_C::_Deque_iterator<_CharT, _CharT&, _CharT*> >::__type
608 __copy_n_a(istreambuf_iterator<_CharT, char_traits<_CharT> >, _Size,
609 _GLIBCXX_STD_C::_Deque_iterator<_CharT, _CharT&, _CharT*>,
610 bool);
611#endif
612
613 /**
614 * @brief Copies the range [first,last) into result.
615 * @ingroup mutating_algorithms
616 * @param __first An input iterator.
617 * @param __last An input iterator.
618 * @param __result An output iterator.
619 * @return result + (last - first)
620 *
621 * This inline function will boil down to a call to @c memmove whenever
622 * possible. Failing that, if random access iterators are passed, then the
623 * loop count will be known (and therefore a candidate for compiler
624 * optimizations such as unrolling). Result may not be contained within
625 * [first,last); the copy_backward function should be used instead.
626 *
627 * Note that the end of the output range is permitted to be contained
628 * within [first,last).
629 */
630 template<typename _II, typename _OI>
631 _GLIBCXX20_CONSTEXPR
632 inline _OI
633 copy(_II __first, _II __last, _OI __result)
634 {
635 // concept requirements
636 __glibcxx_function_requires(_InputIteratorConcept<_II>)
637 __glibcxx_function_requires(_OutputIteratorConcept<_OI,
639 __glibcxx_requires_can_increment_range(__first, __last, __result);
640
642 (std::__miter_base(__first), std::__miter_base(__last), __result);
643 }
644
645#if __cplusplus >= 201103L
646 /**
647 * @brief Moves the range [first,last) into result.
648 * @ingroup mutating_algorithms
649 * @param __first An input iterator.
650 * @param __last An input iterator.
651 * @param __result An output iterator.
652 * @return result + (last - first)
653 *
654 * This inline function will boil down to a call to @c memmove whenever
655 * possible. Failing that, if random access iterators are passed, then the
656 * loop count will be known (and therefore a candidate for compiler
657 * optimizations such as unrolling). Result may not be contained within
658 * [first,last); the move_backward function should be used instead.
659 *
660 * Note that the end of the output range is permitted to be contained
661 * within [first,last).
662 */
663 template<typename _II, typename _OI>
664 _GLIBCXX20_CONSTEXPR
665 inline _OI
666 move(_II __first, _II __last, _OI __result)
667 {
668 // concept requirements
669 __glibcxx_function_requires(_InputIteratorConcept<_II>)
670 __glibcxx_function_requires(_OutputIteratorConcept<_OI,
672 __glibcxx_requires_can_increment_range(__first, __last, __result);
673
674 return std::__copy_move_a<true>(std::__miter_base(__first),
675 std::__miter_base(__last), __result);
676 }
677
678#define _GLIBCXX_MOVE3(_Tp, _Up, _Vp) std::move(_Tp, _Up, _Vp)
679#else
680#define _GLIBCXX_MOVE3(_Tp, _Up, _Vp) std::copy(_Tp, _Up, _Vp)
681#endif
682
683#pragma GCC diagnostic push
684#pragma GCC diagnostic ignored "-Wc++17-extensions"
685 template<bool _IsMove, typename _BI1, typename _BI2>
686 _GLIBCXX20_CONSTEXPR
687 inline _BI2
688 __copy_move_backward_a2(_BI1 __first, _BI1 __last, _BI2 __result)
689 {
690 typedef __decltype(*__first) _InRef;
691 typedef __decltype(*__result) _OutRef;
692 if _GLIBCXX_CONSTEXPR (!__is_trivially_assignable(_OutRef, _InRef))
693 { } /* Skip the optimizations and use the loop at the end. */
694#ifdef __cpp_lib_is_constant_evaluated
696 { } /* Skip the optimizations and use the loop at the end. */
697#endif
698 else if _GLIBCXX_CONSTEXPR (__memcpyable<_BI2, _BI1>::__value)
699 {
700 ptrdiff_t __n = std::distance(__first, __last);
701 std::advance(__result, -__n);
702 if (__builtin_expect(__n > 1, true))
703 {
704 __builtin_memmove(_GLIBCXX_TO_ADDR(__result),
705 _GLIBCXX_TO_ADDR(__first),
706 __n * sizeof(*__first));
707 }
708 else if (__n == 1)
709 std::__assign_one<_IsMove>(__result, __first);
710 return __result;
711 }
712#if __cpp_lib_concepts
713 else if constexpr (__memcpyable_iterators<_BI2, _BI1>)
714 {
715 if (auto __n = __last - __first; __n > 1) [[likely]]
716 {
717 const void* __src = std::to_address(__first);
718 // Advance the iterators and convert to pointers first.
719 // This gives the iterators a chance to do bounds checking.
720 (void) std::to_address(__result -= __n);
721 (void) std::to_address(__first += __n);
722 void* __dest = std::to_address(__result);
723 size_t __nbytes = __n * sizeof(iter_value_t<_BI1>);
724 __builtin_memmove(__dest, __src, __nbytes);
725 }
726 else if (__n == 1)
727 {
728 --__result;
729 std::__assign_one<_IsMove>(__result, __first);
730 }
731 return __result;
732 }
733#endif
734
735 while (__first != __last)
736 {
737 --__last;
738 --__result;
739 std::__assign_one<_IsMove>(__result, __last);
740 }
741 return __result;
742 }
743#pragma GCC diagnostic pop
744
745#undef _GLIBCXX_TO_ADDR
746#undef _GLIBCXX_ADVANCE
747
748 template<bool _IsMove, typename _BI1, typename _BI2>
749 __attribute__((__always_inline__))
750 _GLIBCXX20_CONSTEXPR
751 inline _BI2
752 __copy_move_backward_a1(_BI1 __first, _BI1 __last, _BI2 __result)
753 { return std::__copy_move_backward_a2<_IsMove>(__first, __last, __result); }
754
755 template<bool _IsMove,
756 typename _Tp, typename _Ref, typename _Ptr, typename _OI>
757 _OI
758 __copy_move_backward_a1(_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
759 _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
760 _OI);
761
762 template<bool _IsMove,
763 typename _ITp, typename _IRef, typename _IPtr, typename _OTp>
764 _GLIBCXX_STD_C::_Deque_iterator<_OTp, _OTp&, _OTp*>
765 __copy_move_backward_a1(
766 _GLIBCXX_STD_C::_Deque_iterator<_ITp, _IRef, _IPtr>,
767 _GLIBCXX_STD_C::_Deque_iterator<_ITp, _IRef, _IPtr>,
768 _GLIBCXX_STD_C::_Deque_iterator<_OTp, _OTp&, _OTp*>);
769
770 template<bool _IsMove, typename _II, typename _Tp>
771 typename __gnu_cxx::__enable_if<
772 __is_random_access_iter<_II>::__value,
773 _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*> >::__type
774 __copy_move_backward_a1(_II, _II,
775 _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*>);
776
777 template<bool _IsMove, typename _II, typename _OI>
778 __attribute__((__always_inline__))
779 _GLIBCXX20_CONSTEXPR
780 inline _OI
781 __copy_move_backward_a(_II __first, _II __last, _OI __result)
782 {
783 return std::__niter_wrap(__result,
785 (std::__niter_base(__first), std::__niter_base(__last),
786 std::__niter_base(__result)));
787 }
788
789 template<bool _IsMove,
790 typename _Ite, typename _Seq, typename _Cat, typename _OI>
791 _GLIBCXX20_CONSTEXPR
792 _OI
793 __copy_move_backward_a(
794 const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
795 const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
796 _OI);
797
798 template<bool _IsMove,
799 typename _II, typename _Ite, typename _Seq, typename _Cat>
800 _GLIBCXX20_CONSTEXPR
802 __copy_move_backward_a(_II, _II,
803 const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&);
804
805 template<bool _IsMove,
806 typename _IIte, typename _ISeq, typename _ICat,
807 typename _OIte, typename _OSeq, typename _OCat>
808 _GLIBCXX20_CONSTEXPR
809 ::__gnu_debug::_Safe_iterator<_OIte, _OSeq, _OCat>
810 __copy_move_backward_a(
811 const ::__gnu_debug::_Safe_iterator<_IIte, _ISeq, _ICat>&,
812 const ::__gnu_debug::_Safe_iterator<_IIte, _ISeq, _ICat>&,
813 const ::__gnu_debug::_Safe_iterator<_OIte, _OSeq, _OCat>&);
814
815 /**
816 * @brief Copies the range [first,last) into result.
817 * @ingroup mutating_algorithms
818 * @param __first A bidirectional iterator.
819 * @param __last A bidirectional iterator.
820 * @param __result A bidirectional iterator.
821 * @return result - (last - first)
822 *
823 * The function has the same effect as copy, but starts at the end of the
824 * range and works its way to the start, returning the start of the result.
825 * This inline function will boil down to a call to @c memmove whenever
826 * possible. Failing that, if random access iterators are passed, then the
827 * loop count will be known (and therefore a candidate for compiler
828 * optimizations such as unrolling).
829 *
830 * Result may not be in the range (first,last]. Use copy instead. Note
831 * that the start of the output range may overlap [first,last).
832 */
833 template<typename _BI1, typename _BI2>
834 __attribute__((__always_inline__))
835 _GLIBCXX20_CONSTEXPR
836 inline _BI2
837 copy_backward(_BI1 __first, _BI1 __last, _BI2 __result)
838 {
839 // concept requirements
840 __glibcxx_function_requires(_BidirectionalIteratorConcept<_BI1>)
841 __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<_BI2>)
842 __glibcxx_function_requires(_OutputIteratorConcept<_BI2,
844 __glibcxx_requires_can_decrement_range(__first, __last, __result);
845
847 (std::__miter_base(__first), std::__miter_base(__last), __result);
848 }
849
850#if __cplusplus >= 201103L
851 /**
852 * @brief Moves the range [first,last) into result.
853 * @ingroup mutating_algorithms
854 * @param __first A bidirectional iterator.
855 * @param __last A bidirectional iterator.
856 * @param __result A bidirectional iterator.
857 * @return result - (last - first)
858 *
859 * The function has the same effect as move, but starts at the end of the
860 * range and works its way to the start, returning the start of the result.
861 * This inline function will boil down to a call to @c memmove whenever
862 * possible. Failing that, if random access iterators are passed, then the
863 * loop count will be known (and therefore a candidate for compiler
864 * optimizations such as unrolling).
865 *
866 * Result may not be in the range (first,last]. Use move instead. Note
867 * that the start of the output range may overlap [first,last).
868 */
869 template<typename _BI1, typename _BI2>
870 __attribute__((__always_inline__))
871 _GLIBCXX20_CONSTEXPR
872 inline _BI2
873 move_backward(_BI1 __first, _BI1 __last, _BI2 __result)
874 {
875 // concept requirements
876 __glibcxx_function_requires(_BidirectionalIteratorConcept<_BI1>)
877 __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<_BI2>)
878 __glibcxx_function_requires(_OutputIteratorConcept<_BI2,
880 __glibcxx_requires_can_decrement_range(__first, __last, __result);
881
882 return std::__copy_move_backward_a<true>(std::__miter_base(__first),
883 std::__miter_base(__last),
884 __result);
885 }
886
887#define _GLIBCXX_MOVE_BACKWARD3(_Tp, _Up, _Vp) std::move_backward(_Tp, _Up, _Vp)
888#else
889#define _GLIBCXX_MOVE_BACKWARD3(_Tp, _Up, _Vp) std::copy_backward(_Tp, _Up, _Vp)
890#endif
891
892#pragma GCC diagnostic push
893#pragma GCC diagnostic ignored "-Wc++17-extensions"
894 template<typename _ForwardIterator, typename _Tp>
895 _GLIBCXX20_CONSTEXPR
896 inline void
897 __fill_a1(_ForwardIterator __first, _ForwardIterator __last,
898 const _Tp& __value)
899 {
900#pragma GCC diagnostic push
901#pragma GCC diagnostic ignored "-Wlong-long"
902 // We can optimize this loop by moving the load from __value outside
903 // the loop, but only if we know that making that copy is trivial,
904 // and the assignment in the loop is also trivial (so that the identity
905 // of the operand doesn't matter).
906 const bool __load_outside_loop =
907#if __has_builtin(__is_trivially_constructible) \
908 && __has_builtin(__is_trivially_assignable)
909 __is_trivially_constructible(_Tp, const _Tp&)
910 && __is_trivially_assignable(__decltype(*__first), const _Tp&)
911#else
912 __is_trivially_copyable(_Tp)
913 && __is_same(_Tp, __typeof__(*__first))
914#endif
915 && sizeof(_Tp) <= sizeof(long long);
916#pragma GCC diagnostic pop
917
918 // When the condition is true, we use a copy of __value,
919 // otherwise we just use another reference.
920 typedef typename __gnu_cxx::__conditional_type<__load_outside_loop,
921 const _Tp,
922 const _Tp&>::__type _Up;
923 _Up __val(__value);
924 for (; __first != __last; ++__first)
925 *__first = __val;
926 }
927#pragma GCC diagnostic pop
928
929 // Specialization: for char types we can use memset.
930 template<typename _Up, typename _Tp>
931 _GLIBCXX20_CONSTEXPR
932 inline typename
933 __gnu_cxx::__enable_if<__is_byte<_Up>::__value
934 && (__are_same<_Up, _Tp>::__value // for std::byte
935 || __memcpyable_integer<_Tp>::__width),
936 void>::__type
937 __fill_a1(_Up* __first, _Up* __last, const _Tp& __x)
938 {
939 // This hoists the load out of the loop and also ensures that we don't
940 // use memset for cases where the assignment would be ill-formed.
941 const _Up __val = __x;
942#if __cpp_lib_is_constant_evaluated
944 {
945 for (; __first != __last; ++__first)
946 *__first = __val;
947 return;
948 }
949#endif
950 if (const size_t __len = __last - __first)
951 __builtin_memset(__first, static_cast<unsigned char>(__val), __len);
952 }
953
954 template<typename _Ite, typename _Cont, typename _Tp>
955 __attribute__((__always_inline__))
956 _GLIBCXX20_CONSTEXPR
957 inline void
958 __fill_a1(::__gnu_cxx::__normal_iterator<_Ite, _Cont> __first,
959 ::__gnu_cxx::__normal_iterator<_Ite, _Cont> __last,
960 const _Tp& __value)
961 { std::__fill_a1(__first.base(), __last.base(), __value); }
962
963 template<typename _Tp, typename _VTp>
964 void
965 __fill_a1(const _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*>&,
966 const _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*>&,
967 const _VTp&);
968
969 _GLIBCXX20_CONSTEXPR
970 void
971 __fill_a1(_GLIBCXX_STD_C::_Bit_iterator, _GLIBCXX_STD_C::_Bit_iterator,
972 const bool&);
973
974 template<typename _FIte, typename _Tp>
975 __attribute__((__always_inline__))
976 _GLIBCXX20_CONSTEXPR
977 inline void
978 __fill_a(_FIte __first, _FIte __last, const _Tp& __value)
979 { std::__fill_a1(__first, __last, __value); }
980
981 template<typename _Ite, typename _Seq, typename _Cat, typename _Tp>
982 _GLIBCXX20_CONSTEXPR
983 void
984 __fill_a(const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
985 const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
986 const _Tp&);
987
988 /**
989 * @brief Fills the range [first,last) with copies of value.
990 * @ingroup mutating_algorithms
991 * @param __first A forward iterator.
992 * @param __last A forward iterator.
993 * @param __value A reference-to-const of arbitrary type.
994 * @return Nothing.
995 *
996 * This function fills a range with copies of the same value. For char
997 * types filling contiguous areas of memory, this becomes an inline call
998 * to @c memset or @c wmemset.
999 */
1000 template<typename _ForwardIterator, typename _Tp>
1001 __attribute__((__always_inline__))
1002 _GLIBCXX20_CONSTEXPR
1003 inline void
1004 fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value)
1005 {
1006 // concept requirements
1007 __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
1009 __glibcxx_requires_valid_range(__first, __last);
1010
1011 std::__fill_a(__first, __last, __value);
1012 }
1013
1014#pragma GCC diagnostic push
1015#pragma GCC diagnostic ignored "-Wlong-long"
1016 // Used by fill_n, generate_n, etc. to convert _Size to an integral type:
1017 inline _GLIBCXX_CONSTEXPR int
1018 __size_to_integer(int __n) { return __n; }
1019 inline _GLIBCXX_CONSTEXPR unsigned
1020 __size_to_integer(unsigned __n) { return __n; }
1021 inline _GLIBCXX_CONSTEXPR long
1022 __size_to_integer(long __n) { return __n; }
1023 inline _GLIBCXX_CONSTEXPR unsigned long
1024 __size_to_integer(unsigned long __n) { return __n; }
1025 inline _GLIBCXX_CONSTEXPR long long
1026 __size_to_integer(long long __n) { return __n; }
1027 inline _GLIBCXX_CONSTEXPR unsigned long long
1028 __size_to_integer(unsigned long long __n) { return __n; }
1029
1030#if defined(__GLIBCXX_TYPE_INT_N_0)
1031 __extension__ inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_0
1032 __size_to_integer(__GLIBCXX_TYPE_INT_N_0 __n) { return __n; }
1033 __extension__ inline _GLIBCXX_CONSTEXPR unsigned __GLIBCXX_TYPE_INT_N_0
1034 __size_to_integer(unsigned __GLIBCXX_TYPE_INT_N_0 __n) { return __n; }
1035#endif
1036#if defined(__GLIBCXX_TYPE_INT_N_1)
1037 __extension__ inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_1
1038 __size_to_integer(__GLIBCXX_TYPE_INT_N_1 __n) { return __n; }
1039 __extension__ inline _GLIBCXX_CONSTEXPR unsigned __GLIBCXX_TYPE_INT_N_1
1040 __size_to_integer(unsigned __GLIBCXX_TYPE_INT_N_1 __n) { return __n; }
1041#endif
1042#if defined(__GLIBCXX_TYPE_INT_N_2)
1043 __extension__ inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_2
1044 __size_to_integer(__GLIBCXX_TYPE_INT_N_2 __n) { return __n; }
1045 __extension__ inline _GLIBCXX_CONSTEXPR unsigned __GLIBCXX_TYPE_INT_N_2
1046 __size_to_integer(unsigned __GLIBCXX_TYPE_INT_N_2 __n) { return __n; }
1047#endif
1048#if defined(__GLIBCXX_TYPE_INT_N_3)
1049 __extension__ inline _GLIBCXX_CONSTEXPR unsigned __GLIBCXX_TYPE_INT_N_3
1050 __size_to_integer(__GLIBCXX_TYPE_INT_N_3 __n) { return __n; }
1051 __extension__ inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_3
1052 __size_to_integer(unsigned __GLIBCXX_TYPE_INT_N_3 __n) { return __n; }
1053#endif
1054
1055 inline _GLIBCXX_CONSTEXPR long long
1056 __size_to_integer(float __n) { return (long long)__n; }
1057 inline _GLIBCXX_CONSTEXPR long long
1058 __size_to_integer(double __n) { return (long long)__n; }
1059 inline _GLIBCXX_CONSTEXPR long long
1060 __size_to_integer(long double __n) { return (long long)__n; }
1061#if !defined(__STRICT_ANSI__) && defined(_GLIBCXX_USE_FLOAT128) && !defined(__CUDACC__)
1062 __extension__ inline _GLIBCXX_CONSTEXPR long long
1063 __size_to_integer(__float128 __n) { return (long long)__n; }
1064#endif
1065#pragma GCC diagnostic pop
1066
1067#pragma GCC diagnostic push
1068#pragma GCC diagnostic ignored "-Wc++17-extensions"
1069#pragma GCC diagnostic ignored "-Wlong-long"
1070 template<typename _OutputIterator, typename _Size, typename _Tp>
1071 _GLIBCXX20_CONSTEXPR
1072 inline _OutputIterator
1073 __fill_n_a1(_OutputIterator __first, _Size __n, const _Tp& __value)
1074 {
1075 // See std::__fill_a1 for explanation of this condition.
1076 const bool __load_outside_loop =
1077#if __has_builtin(__is_trivially_constructible) \
1078 && __has_builtin(__is_trivially_assignable)
1079 __is_trivially_constructible(_Tp, const _Tp&)
1080 && __is_trivially_assignable(__decltype(*__first), const _Tp&)
1081#else
1082 __is_trivially_copyable(_Tp)
1083 && __is_same(_Tp, __typeof__(*__first))
1084#endif
1085 && sizeof(_Tp) <= sizeof(long long);
1086
1087 // When the condition is true, we use a copy of __value,
1088 // otherwise we just use another reference.
1089 typedef typename __gnu_cxx::__conditional_type<__load_outside_loop,
1090 const _Tp,
1091 const _Tp&>::__type _Up;
1092 _Up __val(__value);
1093 for (; __n > 0; --__n, (void) ++__first)
1094 *__first = __val;
1095 return __first;
1096 }
1097#pragma GCC diagnostic pop
1098
1099 template<typename _Ite, typename _Seq, typename _Cat, typename _Size,
1100 typename _Tp>
1101 _GLIBCXX20_CONSTEXPR
1102 ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>
1103 __fill_n_a(const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>& __first,
1104 _Size __n, const _Tp& __value,
1106
1107 template<typename _OutputIterator, typename _Size, typename _Tp>
1108 __attribute__((__always_inline__))
1109 _GLIBCXX20_CONSTEXPR
1110 inline _OutputIterator
1111 __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value,
1113 {
1114#if __cplusplus >= 201103L
1115 static_assert(is_integral<_Size>{}, "fill_n must pass integral size");
1116#endif
1117 return __fill_n_a1(__first, __n, __value);
1118 }
1119
1120 template<typename _OutputIterator, typename _Size, typename _Tp>
1121 __attribute__((__always_inline__))
1122 _GLIBCXX20_CONSTEXPR
1123 inline _OutputIterator
1124 __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value,
1126 {
1127#if __cplusplus >= 201103L
1128 static_assert(is_integral<_Size>{}, "fill_n must pass integral size");
1129#endif
1130 return __fill_n_a1(__first, __n, __value);
1131 }
1132
1133 template<typename _OutputIterator, typename _Size, typename _Tp>
1134 __attribute__((__always_inline__))
1135 _GLIBCXX20_CONSTEXPR
1136 inline _OutputIterator
1137 __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value,
1139 {
1140#if __cplusplus >= 201103L
1141 static_assert(is_integral<_Size>{}, "fill_n must pass integral size");
1142#endif
1143 if (__n <= 0)
1144 return __first;
1145
1146 __glibcxx_requires_can_increment(__first, __n);
1147
1148 std::__fill_a(__first, __first + __n, __value);
1149 return __first + __n;
1150 }
1151
1152 /**
1153 * @brief Fills the range [first,first+n) with copies of value.
1154 * @ingroup mutating_algorithms
1155 * @param __first An output iterator.
1156 * @param __n The count of copies to perform.
1157 * @param __value A reference-to-const of arbitrary type.
1158 * @return The iterator at first+n.
1159 *
1160 * This function fills a range with copies of the same value. For char
1161 * types filling contiguous areas of memory, this becomes an inline call
1162 * to @c memset or @c wmemset.
1163 *
1164 * If @p __n is negative, the function does nothing.
1165 */
1166 // _GLIBCXX_RESOLVE_LIB_DEFECTS
1167 // DR 865. More algorithms that throw away information
1168 // DR 426. search_n(), fill_n(), and generate_n() with negative n
1169 template<typename _OI, typename _Size, typename _Tp>
1170 __attribute__((__always_inline__))
1171 _GLIBCXX20_CONSTEXPR
1172 inline _OI
1173 fill_n(_OI __first, _Size __n, const _Tp& __value)
1174 {
1175 // concept requirements
1176 __glibcxx_function_requires(_OutputIteratorConcept<_OI, const _Tp&>)
1177
1178 return std::__fill_n_a(__first, std::__size_to_integer(__n), __value,
1179 std::__iterator_category(__first));
1180 }
1181
1182 template<bool _BoolType>
1183 struct __equal
1184 {
1185 template<typename _II1, typename _II2>
1186 _GLIBCXX20_CONSTEXPR
1187 static bool
1188 equal(_II1 __first1, _II1 __last1, _II2 __first2)
1189 {
1190 for (; __first1 != __last1; ++__first1, (void) ++__first2)
1191 if (!(*__first1 == *__first2))
1192 return false;
1193 return true;
1194 }
1195 };
1196
1197 template<>
1198 struct __equal<true>
1199 {
1200 template<typename _Tp>
1201 _GLIBCXX20_CONSTEXPR
1202 static bool
1203 equal(const _Tp* __first1, const _Tp* __last1, const _Tp* __first2)
1204 {
1205 if (const size_t __len = (__last1 - __first1))
1206 return !std::__memcmp(__first1, __first2, __len);
1207 return true;
1208 }
1209 };
1210
1211 template<typename _Tp, typename _Ref, typename _Ptr, typename _II>
1212 typename __gnu_cxx::__enable_if<
1213 __is_random_access_iter<_II>::__value, bool>::__type
1214 __equal_aux1(_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
1215 _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
1216 _II);
1217
1218 template<typename _Tp1, typename _Ref1, typename _Ptr1,
1219 typename _Tp2, typename _Ref2, typename _Ptr2>
1220 bool
1221 __equal_aux1(_GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
1222 _GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
1223 _GLIBCXX_STD_C::_Deque_iterator<_Tp2, _Ref2, _Ptr2>);
1224
1225 template<typename _II, typename _Tp, typename _Ref, typename _Ptr>
1226 typename __gnu_cxx::__enable_if<
1227 __is_random_access_iter<_II>::__value, bool>::__type
1228 __equal_aux1(_II, _II,
1229 _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>);
1230
1231 template<typename _II1, typename _II2>
1232 _GLIBCXX20_CONSTEXPR
1233 inline bool
1234 __equal_aux1(_II1 __first1, _II1 __last1, _II2 __first2)
1235 {
1236 typedef typename iterator_traits<_II1>::value_type _ValueType1;
1237 const bool __simple = ((__is_integer<_ValueType1>::__value
1238#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_pointer)
1239 || __is_pointer(_ValueType1)
1240#endif
1241#if __glibcxx_byte && __glibcxx_type_trait_variable_templates
1242 // bits/cpp_type_traits.h declares std::byte
1243 || is_same_v<_ValueType1, byte>
1244#endif
1245 ) && __memcmpable<_II1, _II2>::__value);
1246 return std::__equal<__simple>::equal(__first1, __last1, __first2);
1247 }
1248
1249 template<typename _II1, typename _II2>
1250 __attribute__((__always_inline__))
1251 _GLIBCXX20_CONSTEXPR
1252 inline bool
1253 __equal_aux(_II1 __first1, _II1 __last1, _II2 __first2)
1254 {
1255 return std::__equal_aux1(std::__niter_base(__first1),
1256 std::__niter_base(__last1),
1257 std::__niter_base(__first2));
1258 }
1259
1260 template<typename _II1, typename _Seq1, typename _Cat1, typename _II2>
1261 _GLIBCXX20_CONSTEXPR
1262 bool
1263 __equal_aux(const ::__gnu_debug::_Safe_iterator<_II1, _Seq1, _Cat1>&,
1264 const ::__gnu_debug::_Safe_iterator<_II1, _Seq1, _Cat1>&,
1265 _II2);
1266
1267 template<typename _II1, typename _II2, typename _Seq2, typename _Cat2>
1268 _GLIBCXX20_CONSTEXPR
1269 bool
1270 __equal_aux(_II1, _II1,
1271 const ::__gnu_debug::_Safe_iterator<_II2, _Seq2, _Cat2>&);
1272
1273 template<typename _II1, typename _Seq1, typename _Cat1,
1274 typename _II2, typename _Seq2, typename _Cat2>
1275 _GLIBCXX20_CONSTEXPR
1276 bool
1277 __equal_aux(const ::__gnu_debug::_Safe_iterator<_II1, _Seq1, _Cat1>&,
1278 const ::__gnu_debug::_Safe_iterator<_II1, _Seq1, _Cat1>&,
1279 const ::__gnu_debug::_Safe_iterator<_II2, _Seq2, _Cat2>&);
1280
1281 template<typename, typename>
1282 struct __lc_rai
1283 {
1284 template<typename _II1, typename _II2>
1285 _GLIBCXX20_CONSTEXPR
1286 static _II1
1287 __newlast1(_II1, _II1 __last1, _II2, _II2)
1288 { return __last1; }
1289
1290 template<typename _II>
1291 _GLIBCXX20_CONSTEXPR
1292 static bool
1293 __cnd2(_II __first, _II __last)
1294 { return __first != __last; }
1295 };
1296
1297 template<>
1298 struct __lc_rai<random_access_iterator_tag, random_access_iterator_tag>
1299 {
1300 template<typename _RAI1, typename _RAI2>
1301 _GLIBCXX20_CONSTEXPR
1302 static _RAI1
1303 __newlast1(_RAI1 __first1, _RAI1 __last1,
1304 _RAI2 __first2, _RAI2 __last2)
1305 {
1306 const typename iterator_traits<_RAI1>::difference_type
1307 __diff1 = __last1 - __first1;
1308 const typename iterator_traits<_RAI2>::difference_type
1309 __diff2 = __last2 - __first2;
1310 return __diff2 < __diff1 ? __first1 + __diff2 : __last1;
1311 }
1312
1313 template<typename _RAI>
1314 static _GLIBCXX20_CONSTEXPR bool
1315 __cnd2(_RAI, _RAI)
1316 { return true; }
1317 };
1318
1319 template<typename _II1, typename _II2, typename _Compare>
1320 _GLIBCXX20_CONSTEXPR
1321 bool
1322 __lexicographical_compare_impl(_II1 __first1, _II1 __last1,
1323 _II2 __first2, _II2 __last2,
1324 _Compare __comp)
1325 {
1326 typedef typename iterator_traits<_II1>::iterator_category _Category1;
1327 typedef typename iterator_traits<_II2>::iterator_category _Category2;
1328 typedef std::__lc_rai<_Category1, _Category2> __rai_type;
1329
1330 __last1 = __rai_type::__newlast1(__first1, __last1, __first2, __last2);
1331 for (; __first1 != __last1 && __rai_type::__cnd2(__first2, __last2);
1332 ++__first1, (void)++__first2)
1333 {
1334 if (__comp(__first1, __first2))
1335 return true;
1336 if (__comp(__first2, __first1))
1337 return false;
1338 }
1339 return __first1 == __last1 && __first2 != __last2;
1340 }
1341
1342 template<bool _BoolType>
1343 struct __lexicographical_compare
1344 {
1345 template<typename _II1, typename _II2>
1346 _GLIBCXX20_CONSTEXPR
1347 static bool
1348 __lc(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
1349 {
1350 using __gnu_cxx::__ops::__iter_less_iter;
1351 return std::__lexicographical_compare_impl(__first1, __last1,
1352 __first2, __last2,
1353 __iter_less_iter());
1354 }
1355
1356 template<typename _II1, typename _II2>
1357 _GLIBCXX20_CONSTEXPR
1358 static int
1359 __3way(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
1360 {
1361 while (__first1 != __last1)
1362 {
1363 if (__first2 == __last2)
1364 return +1;
1365 if (*__first1 < *__first2)
1366 return -1;
1367 if (*__first2 < *__first1)
1368 return +1;
1369 ++__first1;
1370 ++__first2;
1371 }
1372 return int(__first2 == __last2) - 1;
1373 }
1374 };
1375
1376 template<>
1377 struct __lexicographical_compare<true>
1378 {
1379 template<typename _Tp, typename _Up>
1380 _GLIBCXX20_CONSTEXPR
1381 static bool
1382 __lc(const _Tp* __first1, const _Tp* __last1,
1383 const _Up* __first2, const _Up* __last2)
1384 { return __3way(__first1, __last1, __first2, __last2) < 0; }
1385
1386 template<typename _Tp, typename _Up>
1387 _GLIBCXX20_CONSTEXPR
1388 static ptrdiff_t
1389 __3way(const _Tp* __first1, const _Tp* __last1,
1390 const _Up* __first2, const _Up* __last2)
1391 {
1392 const size_t __len1 = __last1 - __first1;
1393 const size_t __len2 = __last2 - __first2;
1394 if (const size_t __len = std::min(__len1, __len2))
1395 if (int __result = std::__memcmp(__first1, __first2, __len))
1396 return __result;
1397 return ptrdiff_t(__len1 - __len2);
1398 }
1399 };
1400
1401 template<typename _II1, typename _II2>
1402 _GLIBCXX20_CONSTEXPR
1403 inline bool
1404 __lexicographical_compare_aux1(_II1 __first1, _II1 __last1,
1405 _II2 __first2, _II2 __last2)
1406 {
1407 typedef typename iterator_traits<_II1>::value_type _ValueType1;
1408 typedef typename iterator_traits<_II2>::value_type _ValueType2;
1409#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_pointer)
1410 const bool __simple =
1411 (__is_memcmp_ordered_with<_ValueType1, _ValueType2>::__value
1412 && __is_pointer(_II1) && __is_pointer(_II2)
1413#if __cplusplus > 201703L && __glibcxx_concepts
1414 // For C++20 iterator_traits<volatile T*>::value_type is non-volatile
1415 // so __is_byte<T> could be true, but we can't use memcmp with
1416 // volatile data.
1417 && !is_volatile_v<remove_reference_t<iter_reference_t<_II1>>>
1418 && !is_volatile_v<remove_reference_t<iter_reference_t<_II2>>>
1419#endif
1420 );
1421#else
1422 const bool __simple = false;
1423#endif
1424
1425 return std::__lexicographical_compare<__simple>::__lc(__first1, __last1,
1426 __first2, __last2);
1427 }
1428
1429 template<typename _Tp1, typename _Ref1, typename _Ptr1,
1430 typename _Tp2>
1431 bool
1432 __lexicographical_compare_aux1(
1433 _GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
1434 _GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
1435 _Tp2*, _Tp2*);
1436
1437 template<typename _Tp1,
1438 typename _Tp2, typename _Ref2, typename _Ptr2>
1439 bool
1440 __lexicographical_compare_aux1(_Tp1*, _Tp1*,
1441 _GLIBCXX_STD_C::_Deque_iterator<_Tp2, _Ref2, _Ptr2>,
1442 _GLIBCXX_STD_C::_Deque_iterator<_Tp2, _Ref2, _Ptr2>);
1443
1444 template<typename _Tp1, typename _Ref1, typename _Ptr1,
1445 typename _Tp2, typename _Ref2, typename _Ptr2>
1446 bool
1447 __lexicographical_compare_aux1(
1448 _GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
1449 _GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
1450 _GLIBCXX_STD_C::_Deque_iterator<_Tp2, _Ref2, _Ptr2>,
1451 _GLIBCXX_STD_C::_Deque_iterator<_Tp2, _Ref2, _Ptr2>);
1452
1453 template<typename _II1, typename _II2>
1454 _GLIBCXX20_CONSTEXPR
1455 inline bool
1456 __lexicographical_compare_aux(_II1 __first1, _II1 __last1,
1457 _II2 __first2, _II2 __last2)
1458 {
1459 return std::__lexicographical_compare_aux1(std::__niter_base(__first1),
1460 std::__niter_base(__last1),
1461 std::__niter_base(__first2),
1462 std::__niter_base(__last2));
1463 }
1464
1465 template<typename _Iter1, typename _Seq1, typename _Cat1,
1466 typename _II2>
1467 _GLIBCXX20_CONSTEXPR
1468 bool
1469 __lexicographical_compare_aux(
1470 const ::__gnu_debug::_Safe_iterator<_Iter1, _Seq1, _Cat1>&,
1471 const ::__gnu_debug::_Safe_iterator<_Iter1, _Seq1, _Cat1>&,
1472 _II2, _II2);
1473
1474 template<typename _II1,
1475 typename _Iter2, typename _Seq2, typename _Cat2>
1476 _GLIBCXX20_CONSTEXPR
1477 bool
1478 __lexicographical_compare_aux(
1479 _II1, _II1,
1480 const ::__gnu_debug::_Safe_iterator<_Iter2, _Seq2, _Cat2>&,
1481 const ::__gnu_debug::_Safe_iterator<_Iter2, _Seq2, _Cat2>&);
1482
1483 template<typename _Iter1, typename _Seq1, typename _Cat1,
1484 typename _Iter2, typename _Seq2, typename _Cat2>
1485 _GLIBCXX20_CONSTEXPR
1486 bool
1487 __lexicographical_compare_aux(
1488 const ::__gnu_debug::_Safe_iterator<_Iter1, _Seq1, _Cat1>&,
1489 const ::__gnu_debug::_Safe_iterator<_Iter1, _Seq1, _Cat1>&,
1490 const ::__gnu_debug::_Safe_iterator<_Iter2, _Seq2, _Cat2>&,
1491 const ::__gnu_debug::_Safe_iterator<_Iter2, _Seq2, _Cat2>&);
1492
1493 template<typename _ForwardIterator, typename _Tp, typename _Compare>
1494 _GLIBCXX20_CONSTEXPR
1495 _ForwardIterator
1496 __lower_bound(_ForwardIterator __first, _ForwardIterator __last,
1497 const _Tp& __val, _Compare __comp)
1498 {
1499 typedef typename iterator_traits<_ForwardIterator>::difference_type
1500 _DistanceType;
1501
1502 _DistanceType __len = std::distance(__first, __last);
1503
1504 while (__len > 0)
1505 {
1506 _DistanceType __half = __len >> 1;
1507 _ForwardIterator __middle = __first;
1508 std::advance(__middle, __half);
1509 if (__comp(__middle, __val))
1510 {
1511 __first = __middle;
1512 ++__first;
1513 __len = __len - __half - 1;
1514 }
1515 else
1516 __len = __half;
1517 }
1518 return __first;
1519 }
1520
1521 /**
1522 * @brief Finds the first position in which @a val could be inserted
1523 * without changing the ordering.
1524 * @param __first An iterator.
1525 * @param __last Another iterator.
1526 * @param __val The search term.
1527 * @return An iterator pointing to the first element <em>not less
1528 * than</em> @a val, or end() if every element is less than
1529 * @a val.
1530 * @ingroup binary_search_algorithms
1531 */
1532 template<typename _ForwardIterator, typename _Tp>
1533 _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
1534 inline _ForwardIterator
1535 lower_bound(_ForwardIterator __first, _ForwardIterator __last,
1536 const _Tp& __val)
1537 {
1538 // concept requirements
1539 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
1540 __glibcxx_function_requires(_LessThanOpConcept<
1542 __glibcxx_requires_partitioned_lower(__first, __last, __val);
1543
1544 return std::__lower_bound(__first, __last, __val,
1545 __gnu_cxx::__ops::__iter_less_val());
1546 }
1547
1548 /// This is a helper function for the sort routines and for random.tcc.
1549 // Precondition: __n > 0.
1550 template<typename _Tp>
1551 inline _GLIBCXX_CONSTEXPR _Tp
1552 __lg(_Tp __n)
1553 {
1554#if __cplusplus >= 201402L
1555 return std::__bit_width(make_unsigned_t<_Tp>(__n)) - 1;
1556#else
1557#pragma GCC diagnostic push
1558#pragma GCC diagnostic ignored "-Wlong-long"
1559 // Use +__n so it promotes to at least int.
1560 return (sizeof(+__n) * __CHAR_BIT__ - 1)
1561 - (sizeof(+__n) == sizeof(long long)
1562 ? __builtin_clzll(+__n)
1563 : (sizeof(+__n) == sizeof(long)
1564 ? __builtin_clzl(+__n)
1565 : __builtin_clz(+__n)));
1566#pragma GCC diagnostic pop
1567#endif
1568 }
1569
1570_GLIBCXX_BEGIN_NAMESPACE_ALGO
1571
1572 /**
1573 * @brief Tests a range for element-wise equality.
1574 * @ingroup non_mutating_algorithms
1575 * @param __first1 An input iterator.
1576 * @param __last1 An input iterator.
1577 * @param __first2 An input iterator.
1578 * @return A boolean true or false.
1579 *
1580 * This compares the elements of two ranges using @c == and returns true or
1581 * false depending on whether all of the corresponding elements of the
1582 * ranges are equal.
1583 */
1584 template<typename _II1, typename _II2>
1585 _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
1586 inline bool
1588 {
1589 // concept requirements
1590 __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1591 __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1592 __glibcxx_function_requires(_EqualOpConcept<
1595 __glibcxx_requires_can_increment_range(__first1, __last1, __first2);
1596
1597 return std::__equal_aux(__first1, __last1, __first2);
1598 }
1599
1600 /**
1601 * @brief Tests a range for element-wise equality.
1602 * @ingroup non_mutating_algorithms
1603 * @param __first1 An input iterator.
1604 * @param __last1 An input iterator.
1605 * @param __first2 An input iterator.
1606 * @param __binary_pred A binary predicate @link functors
1607 * functor@endlink.
1608 * @return A boolean true or false.
1609 *
1610 * This compares the elements of two ranges using the binary_pred
1611 * parameter, and returns true or
1612 * false depending on whether all of the corresponding elements of the
1613 * ranges are equal.
1614 */
1615 template<typename _IIter1, typename _IIter2, typename _BinaryPredicate>
1616 _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
1617 inline bool
1620 {
1621 // concept requirements
1622 __glibcxx_function_requires(_InputIteratorConcept<_IIter1>)
1623 __glibcxx_function_requires(_InputIteratorConcept<_IIter2>)
1624 __glibcxx_requires_valid_range(__first1, __last1);
1625
1626 for (; __first1 != __last1; ++__first1, (void)++__first2)
1627 if (!bool(__binary_pred(*__first1, *__first2)))
1628 return false;
1629 return true;
1630 }
1631
1632#if __cplusplus >= 201103L
1633#pragma GCC diagnostic push
1634#pragma GCC diagnostic ignored "-Wc++17-extensions" // if constexpr
1635
1636 // 4-iterator version of std::equal<It1, It2> for use in C++11.
1637 template<typename _II1, typename _II2>
1638 _GLIBCXX20_CONSTEXPR
1639 inline bool
1640 __equal4(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
1641 {
1642 using _RATag = random_access_iterator_tag;
1643 using _Cat1 = typename iterator_traits<_II1>::iterator_category;
1644 using _Cat2 = typename iterator_traits<_II2>::iterator_category;
1645 using _RAIters = __and_<is_same<_Cat1, _RATag>, is_same<_Cat2, _RATag>>;
1646 if constexpr (_RAIters::value)
1647 {
1648 if ((__last1 - __first1) != (__last2 - __first2))
1649 return false;
1650 return _GLIBCXX_STD_A::equal(__first1, __last1, __first2);
1651 }
1652 else
1653 {
1654 for (; __first1 != __last1 && __first2 != __last2;
1655 ++__first1, (void)++__first2)
1656 if (!(*__first1 == *__first2))
1657 return false;
1658 return __first1 == __last1 && __first2 == __last2;
1659 }
1660 }
1661
1662 // 4-iterator version of std::equal<It1, It2, BinaryPred> for use in C++11.
1663 template<typename _II1, typename _II2, typename _BinaryPredicate>
1664 _GLIBCXX20_CONSTEXPR
1665 inline bool
1666 __equal4(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2,
1667 _BinaryPredicate __binary_pred)
1668 {
1669 using _RATag = random_access_iterator_tag;
1670 using _Cat1 = typename iterator_traits<_II1>::iterator_category;
1671 using _Cat2 = typename iterator_traits<_II2>::iterator_category;
1672 using _RAIters = __and_<is_same<_Cat1, _RATag>, is_same<_Cat2, _RATag>>;
1673 if constexpr (_RAIters::value)
1674 {
1675 if ((__last1 - __first1) != (__last2 - __first2))
1676 return false;
1677 return _GLIBCXX_STD_A::equal(__first1, __last1, __first2,
1678 __binary_pred);
1679 }
1680 else
1681 {
1682 for (; __first1 != __last1 && __first2 != __last2;
1683 ++__first1, (void)++__first2)
1684 if (!bool(__binary_pred(*__first1, *__first2)))
1685 return false;
1686 return __first1 == __last1 && __first2 == __last2;
1687 }
1688 }
1689#pragma GCC diagnostic pop
1690#endif // C++11
1691
1692#ifdef __glibcxx_robust_nonmodifying_seq_ops // C++ >= 14
1693 /**
1694 * @brief Tests a range for element-wise equality.
1695 * @ingroup non_mutating_algorithms
1696 * @param __first1 An input iterator.
1697 * @param __last1 An input iterator.
1698 * @param __first2 An input iterator.
1699 * @param __last2 An input iterator.
1700 * @return A boolean true or false.
1701 *
1702 * This compares the elements of two ranges using @c == and returns true or
1703 * false depending on whether all of the corresponding elements of the
1704 * ranges are equal.
1705 */
1706 template<typename _II1, typename _II2>
1707 _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
1708 inline bool
1710 {
1711 // concept requirements
1712 __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1713 __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1714 __glibcxx_function_requires(_EqualOpConcept<
1717 __glibcxx_requires_valid_range(__first1, __last1);
1718 __glibcxx_requires_valid_range(__first2, __last2);
1719
1720 return _GLIBCXX_STD_A::__equal4(__first1, __last1, __first2, __last2);
1721 }
1722
1723 /**
1724 * @brief Tests a range for element-wise equality.
1725 * @ingroup non_mutating_algorithms
1726 * @param __first1 An input iterator.
1727 * @param __last1 An input iterator.
1728 * @param __first2 An input iterator.
1729 * @param __last2 An input iterator.
1730 * @param __binary_pred A binary predicate @link functors
1731 * functor@endlink.
1732 * @return A boolean true or false.
1733 *
1734 * This compares the elements of two ranges using the binary_pred
1735 * parameter, and returns true or
1736 * false depending on whether all of the corresponding elements of the
1737 * ranges are equal.
1738 */
1739 template<typename _IIter1, typename _IIter2, typename _BinaryPredicate>
1740 _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
1741 inline bool
1744 {
1745 // concept requirements
1746 __glibcxx_function_requires(_InputIteratorConcept<_IIter1>)
1747 __glibcxx_function_requires(_InputIteratorConcept<_IIter2>)
1748 __glibcxx_requires_valid_range(__first1, __last1);
1749 __glibcxx_requires_valid_range(__first2, __last2);
1750
1751 return _GLIBCXX_STD_A::__equal4(__first1, __last1, __first2, __last2,
1753 }
1754#endif // __glibcxx_robust_nonmodifying_seq_ops
1755
1756 /**
1757 * @brief Performs @b dictionary comparison on ranges.
1758 * @ingroup sorting_algorithms
1759 * @param __first1 An input iterator.
1760 * @param __last1 An input iterator.
1761 * @param __first2 An input iterator.
1762 * @param __last2 An input iterator.
1763 * @return A boolean true or false.
1764 *
1765 * <em>Returns true if the sequence of elements defined by the range
1766 * [first1,last1) is lexicographically less than the sequence of elements
1767 * defined by the range [first2,last2). Returns false otherwise.</em>
1768 * (Quoted from [25.3.8]/1.) If the iterators are all character pointers,
1769 * then this is an inline call to @c memcmp.
1770 */
1771 template<typename _II1, typename _II2>
1772 _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
1773 inline bool
1774 lexicographical_compare(_II1 __first1, _II1 __last1,
1776 {
1777#ifdef _GLIBCXX_CONCEPT_CHECKS
1778 // concept requirements
1781#endif
1782 __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1783 __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1784 __glibcxx_function_requires(_LessThanOpConcept<_ValueType1, _ValueType2>)
1785 __glibcxx_function_requires(_LessThanOpConcept<_ValueType2, _ValueType1>)
1786 __glibcxx_requires_valid_range(__first1, __last1);
1787 __glibcxx_requires_valid_range(__first2, __last2);
1788
1789 return std::__lexicographical_compare_aux(__first1, __last1,
1790 __first2, __last2);
1791 }
1792
1793 /**
1794 * @brief Performs @b dictionary comparison on ranges.
1795 * @ingroup sorting_algorithms
1796 * @param __first1 An input iterator.
1797 * @param __last1 An input iterator.
1798 * @param __first2 An input iterator.
1799 * @param __last2 An input iterator.
1800 * @param __comp A @link comparison_functors comparison functor@endlink.
1801 * @return A boolean true or false.
1802 *
1803 * The same as the four-parameter @c lexicographical_compare, but uses the
1804 * comp parameter instead of @c <.
1805 */
1806 template<typename _II1, typename _II2, typename _Compare>
1807 _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
1808 inline bool
1809 lexicographical_compare(_II1 __first1, _II1 __last1,
1810 _II2 __first2, _II2 __last2, _Compare __comp)
1811 {
1812 // concept requirements
1813 __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1814 __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1815 __glibcxx_requires_valid_range(__first1, __last1);
1816 __glibcxx_requires_valid_range(__first2, __last2);
1817
1818 return std::__lexicographical_compare_impl
1820 __gnu_cxx::__ops::__iter_comp_iter(__comp));
1821 }
1822
1823#if __cpp_lib_three_way_comparison
1824 // Both iterators refer to contiguous ranges of unsigned narrow characters,
1825 // or std::byte, or big-endian unsigned integers, suitable for comparison
1826 // using memcmp.
1827 template<typename _Iter1, typename _Iter2>
1828 concept __memcmp_ordered_with
1829 = (__is_memcmp_ordered_with<iter_value_t<_Iter1>,
1830 iter_value_t<_Iter2>>::__value)
1831 && contiguous_iterator<_Iter1> && contiguous_iterator<_Iter2>;
1832
1833 // Return a struct with two members, initialized to the smaller of x and y
1834 // (or x if they compare equal) and the result of the comparison x <=> y.
1835 template<typename _Tp>
1836 constexpr auto
1837 __min_cmp(_Tp __x, _Tp __y)
1838 {
1839 struct _Res {
1840 _Tp _M_min;
1841 decltype(__x <=> __y) _M_cmp;
1842 };
1843 auto __c = __x <=> __y;
1844 if (__c > 0)
1845 return _Res{__y, __c};
1846 return _Res{__x, __c};
1847 }
1848
1849 /**
1850 * @brief Performs dictionary comparison on ranges.
1851 * @ingroup sorting_algorithms
1852 * @param __first1 An input iterator.
1853 * @param __last1 An input iterator.
1854 * @param __first2 An input iterator.
1855 * @param __last2 An input iterator.
1856 * @param __comp A @link comparison_functors comparison functor@endlink.
1857 * @return The comparison category that `__comp(*__first1, *__first2)`
1858 * returns.
1859 */
1860 template<typename _InputIter1, typename _InputIter2, typename _Comp>
1861 [[nodiscard]] constexpr auto
1866 _Comp __comp)
1867 -> decltype(__comp(*__first1, *__first2))
1868 {
1869 // concept requirements
1870 __glibcxx_function_requires(_InputIteratorConcept<_InputIter1>)
1871 __glibcxx_function_requires(_InputIteratorConcept<_InputIter2>)
1872 __glibcxx_requires_valid_range(__first1, __last1);
1873 __glibcxx_requires_valid_range(__first2, __last2);
1874
1875 using _Cat = decltype(__comp(*__first1, *__first2));
1877
1878 if (!std::__is_constant_evaluated())
1882 {
1883 const auto [__len, __lencmp] = _GLIBCXX_STD_A::
1884 __min_cmp(__last1 - __first1, __last2 - __first2);
1885 if (__len)
1886 {
1887 const auto __blen = __len * sizeof(*__first1);
1888 const auto __c
1890 if (__c != 0)
1891 return __c;
1892 }
1893 return __lencmp;
1894 }
1895
1896 while (__first1 != __last1)
1897 {
1898 if (__first2 == __last2)
1899 return strong_ordering::greater;
1900 if (auto __cmp = __comp(*__first1, *__first2); __cmp != 0)
1901 return __cmp;
1902 ++__first1;
1903 ++__first2;
1904 }
1905 return (__first2 == __last2) <=> true; // See PR 94006
1906 }
1907
1908 template<typename _InputIter1, typename _InputIter2>
1909 constexpr auto
1910 lexicographical_compare_three_way(_InputIter1 __first1,
1911 _InputIter1 __last1,
1912 _InputIter2 __first2,
1913 _InputIter2 __last2)
1914 {
1915 return _GLIBCXX_STD_A::
1916 lexicographical_compare_three_way(__first1, __last1, __first2, __last2,
1917 compare_three_way{});
1918 }
1919#endif // three_way_comparison
1920
1921 template<typename _InputIterator1, typename _InputIterator2,
1922 typename _BinaryPredicate>
1923 _GLIBCXX20_CONSTEXPR
1924 pair<_InputIterator1, _InputIterator2>
1925 __mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1926 _InputIterator2 __first2, _BinaryPredicate __binary_pred)
1927 {
1928 while (__first1 != __last1 && __binary_pred(__first1, __first2))
1929 {
1930 ++__first1;
1931 ++__first2;
1932 }
1933 return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
1934 }
1935
1936 /**
1937 * @brief Finds the places in ranges which don't match.
1938 * @ingroup non_mutating_algorithms
1939 * @param __first1 An input iterator.
1940 * @param __last1 An input iterator.
1941 * @param __first2 An input iterator.
1942 * @return A pair of iterators pointing to the first mismatch.
1943 *
1944 * This compares the elements of two ranges using @c == and returns a pair
1945 * of iterators. The first iterator points into the first range, the
1946 * second iterator points into the second range, and the elements pointed
1947 * to by the iterators are not equal.
1948 */
1949 template<typename _InputIterator1, typename _InputIterator2>
1950 _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
1951 inline pair<_InputIterator1, _InputIterator2>
1954 {
1955 // concept requirements
1956 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
1957 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
1958 __glibcxx_function_requires(_EqualOpConcept<
1961 __glibcxx_requires_valid_range(__first1, __last1);
1962
1963 return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2,
1964 __gnu_cxx::__ops::__iter_equal_to_iter());
1965 }
1966
1967 /**
1968 * @brief Finds the places in ranges which don't match.
1969 * @ingroup non_mutating_algorithms
1970 * @param __first1 An input iterator.
1971 * @param __last1 An input iterator.
1972 * @param __first2 An input iterator.
1973 * @param __binary_pred A binary predicate @link functors
1974 * functor@endlink.
1975 * @return A pair of iterators pointing to the first mismatch.
1976 *
1977 * This compares the elements of two ranges using the binary_pred
1978 * parameter, and returns a pair
1979 * of iterators. The first iterator points into the first range, the
1980 * second iterator points into the second range, and the elements pointed
1981 * to by the iterators are not equal.
1982 */
1983 template<typename _InputIterator1, typename _InputIterator2,
1984 typename _BinaryPredicate>
1985 _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
1986 inline pair<_InputIterator1, _InputIterator2>
1989 {
1990 // concept requirements
1991 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
1992 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
1993 __glibcxx_requires_valid_range(__first1, __last1);
1994
1995 return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2,
1996 __gnu_cxx::__ops::__iter_comp_iter(__binary_pred));
1997 }
1998
1999#if __glibcxx_robust_nonmodifying_seq_ops // C++ >= 14
2000 template<typename _InputIterator1, typename _InputIterator2,
2001 typename _BinaryPredicate>
2002 _GLIBCXX20_CONSTEXPR
2003 pair<_InputIterator1, _InputIterator2>
2004 __mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
2005 _InputIterator2 __first2, _InputIterator2 __last2,
2006 _BinaryPredicate __binary_pred)
2007 {
2008 while (__first1 != __last1 && __first2 != __last2
2009 && __binary_pred(__first1, __first2))
2010 {
2011 ++__first1;
2012 ++__first2;
2013 }
2014 return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
2015 }
2016
2017 /**
2018 * @brief Finds the places in ranges which don't match.
2019 * @ingroup non_mutating_algorithms
2020 * @param __first1 An input iterator.
2021 * @param __last1 An input iterator.
2022 * @param __first2 An input iterator.
2023 * @param __last2 An input iterator.
2024 * @return A pair of iterators pointing to the first mismatch.
2025 *
2026 * This compares the elements of two ranges using @c == and returns a pair
2027 * of iterators. The first iterator points into the first range, the
2028 * second iterator points into the second range, and the elements pointed
2029 * to by the iterators are not equal.
2030 */
2031 template<typename _InputIterator1, typename _InputIterator2>
2032 _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
2033 inline pair<_InputIterator1, _InputIterator2>
2036 {
2037 // concept requirements
2038 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
2039 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
2040 __glibcxx_function_requires(_EqualOpConcept<
2043 __glibcxx_requires_valid_range(__first1, __last1);
2044 __glibcxx_requires_valid_range(__first2, __last2);
2045
2046 return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2, __last2,
2047 __gnu_cxx::__ops::__iter_equal_to_iter());
2048 }
2049
2050 /**
2051 * @brief Finds the places in ranges which don't match.
2052 * @ingroup non_mutating_algorithms
2053 * @param __first1 An input iterator.
2054 * @param __last1 An input iterator.
2055 * @param __first2 An input iterator.
2056 * @param __last2 An input iterator.
2057 * @param __binary_pred A binary predicate @link functors
2058 * functor@endlink.
2059 * @return A pair of iterators pointing to the first mismatch.
2060 *
2061 * This compares the elements of two ranges using the binary_pred
2062 * parameter, and returns a pair
2063 * of iterators. The first iterator points into the first range, the
2064 * second iterator points into the second range, and the elements pointed
2065 * to by the iterators are not equal.
2066 */
2067 template<typename _InputIterator1, typename _InputIterator2,
2068 typename _BinaryPredicate>
2069 _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
2070 inline pair<_InputIterator1, _InputIterator2>
2074 {
2075 // concept requirements
2076 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
2077 __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
2078 __glibcxx_requires_valid_range(__first1, __last1);
2079 __glibcxx_requires_valid_range(__first2, __last2);
2080
2081 return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2, __last2,
2082 __gnu_cxx::__ops::__iter_comp_iter(__binary_pred));
2083 }
2084#endif
2085
2086_GLIBCXX_END_NAMESPACE_ALGO
2087
2088 // Implementation of std::find_if, also used in std::remove_if and others.
2089 template<typename _Iterator, typename _Predicate>
2090 _GLIBCXX20_CONSTEXPR
2091 inline _Iterator
2092 __find_if(_Iterator __first, _Iterator __last, _Predicate __pred)
2093 {
2094#pragma GCC unroll 4
2095 while (__first != __last && !__pred(__first))
2096 ++__first;
2097 return __first;
2098 }
2099
2100 template<typename _InputIterator, typename _Predicate>
2101 _GLIBCXX20_CONSTEXPR
2102 typename iterator_traits<_InputIterator>::difference_type
2103 __count_if(_InputIterator __first, _InputIterator __last, _Predicate __pred)
2104 {
2105 typename iterator_traits<_InputIterator>::difference_type __n = 0;
2106 for (; __first != __last; ++__first)
2107 if (__pred(__first))
2108 ++__n;
2109 return __n;
2110 }
2111
2112 template<typename _ForwardIterator, typename _Predicate>
2113 _GLIBCXX20_CONSTEXPR
2114 _ForwardIterator
2115 __remove_if(_ForwardIterator __first, _ForwardIterator __last,
2116 _Predicate __pred)
2117 {
2118 __first = std::__find_if(__first, __last, __pred);
2119 if (__first == __last)
2120 return __first;
2121 _ForwardIterator __result = __first;
2122 ++__first;
2123 for (; __first != __last; ++__first)
2124 if (!__pred(__first))
2125 {
2126 *__result = _GLIBCXX_MOVE(*__first);
2127 ++__result;
2128 }
2129 return __result;
2130 }
2131
2132 template<typename _ForwardIterator1, typename _ForwardIterator2,
2133 typename _BinaryPredicate>
2134 _GLIBCXX20_CONSTEXPR
2135 _ForwardIterator1
2136 __search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
2137 _ForwardIterator2 __first2, _ForwardIterator2 __last2,
2138 _BinaryPredicate __predicate)
2139 {
2140 // Test for empty ranges
2141 if (__first1 == __last1 || __first2 == __last2)
2142 return __first1;
2143
2144 // Test for a pattern of length 1.
2145 _ForwardIterator2 __p1(__first2);
2146 if (++__p1 == __last2)
2147 return std::__find_if(__first1, __last1,
2148 __gnu_cxx::__ops::__iter_comp_iter(__predicate, __first2));
2149
2150 // General case.
2151 _ForwardIterator1 __current = __first1;
2152
2153 for (;;)
2154 {
2155 __first1 =
2156 std::__find_if(__first1, __last1,
2157 __gnu_cxx::__ops::__iter_comp_iter(__predicate, __first2));
2158
2159 if (__first1 == __last1)
2160 return __last1;
2161
2162 _ForwardIterator2 __p = __p1;
2163 __current = __first1;
2164 if (++__current == __last1)
2165 return __last1;
2166
2167 while (__predicate(__current, __p))
2168 {
2169 if (++__p == __last2)
2170 return __first1;
2171 if (++__current == __last1)
2172 return __last1;
2173 }
2174 ++__first1;
2175 }
2176 return __first1;
2177 }
2178
2179#if __cplusplus >= 201103L
2180 template<typename _ForwardIterator1, typename _ForwardIterator2,
2181 typename _BinaryPredicate>
2182 _GLIBCXX20_CONSTEXPR
2183 bool
2184 __is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
2185 _ForwardIterator2 __first2, _BinaryPredicate __pred)
2186 {
2187 // Efficiently compare identical prefixes: O(N) if sequences
2188 // have the same elements in the same order.
2189 for (; __first1 != __last1; ++__first1, (void)++__first2)
2190 if (!__pred(__first1, __first2))
2191 break;
2192
2193 if (__first1 == __last1)
2194 return true;
2195
2196 // Establish __last2 assuming equal ranges by iterating over the
2197 // rest of the list.
2198 _ForwardIterator2 __last2 = __first2;
2199 std::advance(__last2, std::distance(__first1, __last1));
2200 for (_ForwardIterator1 __scan = __first1; __scan != __last1; ++__scan)
2201 {
2202 if (__scan != std::__find_if(__first1, __scan,
2203 __gnu_cxx::__ops::__iter_comp_iter(__pred, __scan)))
2204 continue; // We've seen this one before.
2205
2206 auto __matches
2207 = std::__count_if(__first2, __last2,
2208 __gnu_cxx::__ops::__iter_comp_iter(__pred, __scan));
2209 if (0 == __matches ||
2210 std::__count_if(__scan, __last1,
2211 __gnu_cxx::__ops::__iter_comp_iter(__pred, __scan))
2212 != __matches)
2213 return false;
2214 }
2215 return true;
2216 }
2217
2218 /**
2219 * @brief Checks whether a permutation of the second sequence is equal
2220 * to the first sequence.
2221 * @ingroup non_mutating_algorithms
2222 * @param __first1 Start of first range.
2223 * @param __last1 End of first range.
2224 * @param __first2 Start of second range.
2225 * @return true if there exists a permutation of the elements in the range
2226 * [__first2, __first2 + (__last1 - __first1)), beginning with
2227 * ForwardIterator2 begin, such that equal(__first1, __last1, begin)
2228 * returns true; otherwise, returns false.
2229 */
2230 template<typename _ForwardIterator1, typename _ForwardIterator2>
2231 _GLIBCXX20_CONSTEXPR
2232 inline bool
2235 {
2236 // concept requirements
2237 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
2238 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
2239 __glibcxx_function_requires(_EqualOpConcept<
2242 __glibcxx_requires_valid_range(__first1, __last1);
2243
2244 return std::__is_permutation(__first1, __last1, __first2,
2245 __gnu_cxx::__ops::__iter_equal_to_iter());
2246 }
2247#endif // C++11
2248
2249_GLIBCXX_BEGIN_NAMESPACE_ALGO
2250
2251 /**
2252 * @brief Search a sequence for a matching sub-sequence using a predicate.
2253 * @ingroup non_mutating_algorithms
2254 * @param __first1 A forward iterator.
2255 * @param __last1 A forward iterator.
2256 * @param __first2 A forward iterator.
2257 * @param __last2 A forward iterator.
2258 * @param __predicate A binary predicate.
2259 * @return The first iterator @c i in the range
2260 * @p [__first1,__last1-(__last2-__first2)) such that
2261 * @p __predicate(*(i+N),*(__first2+N)) is true for each @c N in the range
2262 * @p [0,__last2-__first2), or @p __last1 if no such iterator exists.
2263 *
2264 * Searches the range @p [__first1,__last1) for a sub-sequence that
2265 * compares equal value-by-value with the sequence given by @p
2266 * [__first2,__last2), using @p __predicate to determine equality,
2267 * and returns an iterator to the first element of the
2268 * sub-sequence, or @p __last1 if no such iterator exists.
2269 *
2270 * @see search(_ForwardIter1, _ForwardIter1, _ForwardIter2, _ForwardIter2)
2271 */
2272 template<typename _ForwardIterator1, typename _ForwardIterator2,
2273 typename _BinaryPredicate>
2274 _GLIBCXX20_CONSTEXPR
2275 inline _ForwardIterator1
2279 {
2280 // concept requirements
2281 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
2282 __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
2283 __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
2286 __glibcxx_requires_valid_range(__first1, __last1);
2287 __glibcxx_requires_valid_range(__first2, __last2);
2288
2289 return std::__search(__first1, __last1, __first2, __last2,
2290 __gnu_cxx::__ops::__iter_comp_iter(__predicate));
2291 }
2292
2293_GLIBCXX_END_NAMESPACE_ALGO
2294_GLIBCXX_END_NAMESPACE_VERSION
2295} // namespace std
2296
2297// NB: This file is included within many other C++ includes, as a way
2298// of getting the base algorithms. So, make sure that parallel bits
2299// come in too if requested.
2300#ifdef _GLIBCXX_PARALLEL
2301# include <parallel/algobase.h>
2302#endif
2303
2304#endif
Parallel STL function calls corresponding to the stl_algobase.h header. The functions defined here ma...
constexpr _Tp * to_address(_Tp *__ptr) noexcept
Obtain address referenced by a pointer to an object.
Definition ptr_traits.h:232
constexpr std::remove_reference< _Tp >::type && move(_Tp &&__t) noexcept
Convert a value to an rvalue.
Definition move.h:138
constexpr _BI2 move_backward(_BI1 __first, _BI1 __last, _BI2 __result)
Moves the range [first,last) into result.
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.
constexpr const _Tp & max(const _Tp &, const _Tp &)
This does what you think it does.
constexpr const _Tp & min(const _Tp &, const _Tp &)
This does what you think it does.
constexpr iterator_traits< _Iter >::iterator_category __iterator_category(const _Iter &)
ISO C++ entities toplevel namespace is std.
constexpr iterator_traits< _InputIterator >::difference_type distance(_InputIterator __first, _InputIterator __last)
A generalization of pointer arithmetic.
constexpr _Tp __lg(_Tp __n)
This is a helper function for the sort routines and for random.tcc.
constexpr void advance(_InputIterator &__i, _Distance __n)
A generalization of pointer arithmetic.
Safe iterator wrapper.
Marking input iterators.
Marking output iterators.
Random-access iterators support a superset of bidirectional iterator operations.
Traits class for iterators.