libstdc++
stl_algobase.h
Go to the documentation of this file.
1 // Core algorithmic facilities -*- C++ -*-
2 
3 // Copyright (C) 2001-2020 Free Software Foundation, Inc.
4 //
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
9 // any later version.
10 
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
15 
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
19 
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 // <http://www.gnu.org/licenses/>.
24 
25 /*
26  *
27  * Copyright (c) 1994
28  * Hewlett-Packard Company
29  *
30  * Permission to use, copy, modify, distribute and sell this software
31  * and its documentation for any purpose is hereby granted without fee,
32  * provided that the above copyright notice appear in all copies and
33  * that both that copyright notice and this permission notice appear
34  * in supporting documentation. Hewlett-Packard Company makes no
35  * representations about the suitability of this software for any
36  * purpose. It is provided "as is" without express or implied warranty.
37  *
38  *
39  * Copyright (c) 1996-1998
40  * Silicon Graphics Computer Systems, Inc.
41  *
42  * Permission to use, copy, modify, distribute and sell this software
43  * and its documentation for any purpose is hereby granted without fee,
44  * provided that the above copyright notice appear in all copies and
45  * that both that copyright notice and this permission notice appear
46  * in supporting documentation. Silicon Graphics makes no
47  * representations about the suitability of this software for any
48  * purpose. It is provided "as is" without express or implied warranty.
49  */
50 
51 /** @file bits/stl_algobase.h
52  * This is an internal header file, included by other library headers.
53  * Do not attempt to use it directly. @headername{algorithm}
54  */
55 
56 #ifndef _STL_ALGOBASE_H
57 #define _STL_ALGOBASE_H 1
58 
59 #include <bits/c++config.h>
60 #include <bits/functexcept.h>
61 #include <bits/cpp_type_traits.h>
62 #include <ext/type_traits.h>
63 #include <ext/numeric_traits.h>
64 #include <bits/stl_pair.h>
67 #include <bits/stl_iterator.h>
68 #include <bits/concept_check.h>
69 #include <debug/debug.h>
70 #include <bits/move.h> // For std::swap
71 #include <bits/predefined_ops.h>
72 #if __cplusplus >= 201103L
73 # include <type_traits>
74 #endif
75 #if __cplusplus > 201703L
76 # include <compare>
77 #endif
78 
79 namespace std _GLIBCXX_VISIBILITY(default)
80 {
81 _GLIBCXX_BEGIN_NAMESPACE_VERSION
82 
83  /*
84  * A constexpr wrapper for __builtin_memcmp.
85  * @param __num The number of elements of type _Tp (not bytes).
86  */
87  template<typename _Tp>
88  _GLIBCXX14_CONSTEXPR
89  inline int
90  __memcmp(const _Tp* __first1, const _Tp* __first2, size_t __num)
91  {
92 #ifdef __cpp_lib_is_constant_evaluated
93  if (std::is_constant_evaluated())
94  {
95  for(; __num > 0; ++__first1, ++__first2, --__num)
96  if (*__first1 != *__first2)
97  return *__first1 < *__first2 ? -1 : 1;
98  return 0;
99  }
100  else
101 #endif
102  return __builtin_memcmp(__first1, __first2, sizeof(_Tp) * __num);
103  }
104 
105 #if __cplusplus < 201103L
106  // See http://gcc.gnu.org/ml/libstdc++/2004-08/msg00167.html: in a
107  // nutshell, we are partially implementing the resolution of DR 187,
108  // when it's safe, i.e., the value_types are equal.
109  template<bool _BoolType>
110  struct __iter_swap
111  {
112  template<typename _ForwardIterator1, typename _ForwardIterator2>
113  static void
114  iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
115  {
116  typedef typename iterator_traits<_ForwardIterator1>::value_type
117  _ValueType1;
118  _ValueType1 __tmp = *__a;
119  *__a = *__b;
120  *__b = __tmp;
121  }
122  };
123 
124  template<>
125  struct __iter_swap<true>
126  {
127  template<typename _ForwardIterator1, typename _ForwardIterator2>
128  static void
129  iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
130  {
131  swap(*__a, *__b);
132  }
133  };
134 #endif // C++03
135 
136  /**
137  * @brief Swaps the contents of two iterators.
138  * @ingroup mutating_algorithms
139  * @param __a An iterator.
140  * @param __b Another iterator.
141  * @return Nothing.
142  *
143  * This function swaps the values pointed to by two iterators, not the
144  * iterators themselves.
145  */
146  template<typename _ForwardIterator1, typename _ForwardIterator2>
147  _GLIBCXX20_CONSTEXPR
148  inline void
149  iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
150  {
151  // concept requirements
152  __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
153  _ForwardIterator1>)
154  __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
155  _ForwardIterator2>)
156 
157 #if __cplusplus < 201103L
159  _ValueType1;
161  _ValueType2;
162 
163  __glibcxx_function_requires(_ConvertibleConcept<_ValueType1,
164  _ValueType2>)
165  __glibcxx_function_requires(_ConvertibleConcept<_ValueType2,
166  _ValueType1>)
167 
169  _ReferenceType1;
171  _ReferenceType2;
172  std::__iter_swap<__are_same<_ValueType1, _ValueType2>::__value
173  && __are_same<_ValueType1&, _ReferenceType1>::__value
174  && __are_same<_ValueType2&, _ReferenceType2>::__value>::
175  iter_swap(__a, __b);
176 #else
177  // _GLIBCXX_RESOLVE_LIB_DEFECTS
178  // 187. iter_swap underspecified
179  swap(*__a, *__b);
180 #endif
181  }
182 
183  /**
184  * @brief Swap the elements of two sequences.
185  * @ingroup mutating_algorithms
186  * @param __first1 A forward iterator.
187  * @param __last1 A forward iterator.
188  * @param __first2 A forward iterator.
189  * @return An iterator equal to @p first2+(last1-first1).
190  *
191  * Swaps each element in the range @p [first1,last1) with the
192  * corresponding element in the range @p [first2,(last1-first1)).
193  * The ranges must not overlap.
194  */
195  template<typename _ForwardIterator1, typename _ForwardIterator2>
196  _GLIBCXX20_CONSTEXPR
197  _ForwardIterator2
198  swap_ranges(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
199  _ForwardIterator2 __first2)
200  {
201  // concept requirements
202  __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
203  _ForwardIterator1>)
204  __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
205  _ForwardIterator2>)
206  __glibcxx_requires_valid_range(__first1, __last1);
207 
208  for (; __first1 != __last1; ++__first1, (void)++__first2)
209  std::iter_swap(__first1, __first2);
210  return __first2;
211  }
212 
213  /**
214  * @brief This does what you think it does.
215  * @ingroup sorting_algorithms
216  * @param __a A thing of arbitrary type.
217  * @param __b Another thing of arbitrary type.
218  * @return The lesser of the parameters.
219  *
220  * This is the simple classic generic implementation. It will work on
221  * temporary expressions, since they are only evaluated once, unlike a
222  * preprocessor macro.
223  */
224  template<typename _Tp>
225  _GLIBCXX14_CONSTEXPR
226  inline const _Tp&
227  min(const _Tp& __a, const _Tp& __b)
228  {
229  // concept requirements
230  __glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
231  //return __b < __a ? __b : __a;
232  if (__b < __a)
233  return __b;
234  return __a;
235  }
236 
237  /**
238  * @brief This does what you think it does.
239  * @ingroup sorting_algorithms
240  * @param __a A thing of arbitrary type.
241  * @param __b Another thing of arbitrary type.
242  * @return The greater of the parameters.
243  *
244  * This is the simple classic generic implementation. It will work on
245  * temporary expressions, since they are only evaluated once, unlike a
246  * preprocessor macro.
247  */
248  template<typename _Tp>
249  _GLIBCXX14_CONSTEXPR
250  inline const _Tp&
251  max(const _Tp& __a, const _Tp& __b)
252  {
253  // concept requirements
254  __glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
255  //return __a < __b ? __b : __a;
256  if (__a < __b)
257  return __b;
258  return __a;
259  }
260 
261  /**
262  * @brief This does what you think it does.
263  * @ingroup sorting_algorithms
264  * @param __a A thing of arbitrary type.
265  * @param __b Another thing of arbitrary type.
266  * @param __comp A @link comparison_functors comparison functor@endlink.
267  * @return The lesser of the parameters.
268  *
269  * This will work on temporary expressions, since they are only evaluated
270  * once, unlike a preprocessor macro.
271  */
272  template<typename _Tp, typename _Compare>
273  _GLIBCXX14_CONSTEXPR
274  inline const _Tp&
275  min(const _Tp& __a, const _Tp& __b, _Compare __comp)
276  {
277  //return __comp(__b, __a) ? __b : __a;
278  if (__comp(__b, __a))
279  return __b;
280  return __a;
281  }
282 
283  /**
284  * @brief This does what you think it does.
285  * @ingroup sorting_algorithms
286  * @param __a A thing of arbitrary type.
287  * @param __b Another thing of arbitrary type.
288  * @param __comp A @link comparison_functors comparison functor@endlink.
289  * @return The greater of the parameters.
290  *
291  * This will work on temporary expressions, since they are only evaluated
292  * once, unlike a preprocessor macro.
293  */
294  template<typename _Tp, typename _Compare>
295  _GLIBCXX14_CONSTEXPR
296  inline const _Tp&
297  max(const _Tp& __a, const _Tp& __b, _Compare __comp)
298  {
299  //return __comp(__a, __b) ? __b : __a;
300  if (__comp(__a, __b))
301  return __b;
302  return __a;
303  }
304 
305  // Fallback implementation of the function in bits/stl_iterator.h used to
306  // remove the __normal_iterator wrapper. See copy, fill, ...
307  template<typename _Iterator>
308  _GLIBCXX20_CONSTEXPR
309  inline _Iterator
310  __niter_base(_Iterator __it)
312  { return __it; }
313 
314  // Reverse the __niter_base transformation to get a
315  // __normal_iterator back again (this assumes that __normal_iterator
316  // is only used to wrap random access iterators, like pointers).
317  template<typename _From, typename _To>
318  _GLIBCXX20_CONSTEXPR
319  inline _From
320  __niter_wrap(_From __from, _To __res)
321  { return __from + (__res - std::__niter_base(__from)); }
322 
323  // No need to wrap, iterator already has the right type.
324  template<typename _Iterator>
325  _GLIBCXX20_CONSTEXPR
326  inline _Iterator
327  __niter_wrap(const _Iterator&, _Iterator __res)
328  { return __res; }
329 
330  // All of these auxiliary structs serve two purposes. (1) Replace
331  // calls to copy with memmove whenever possible. (Memmove, not memcpy,
332  // because the input and output ranges are permitted to overlap.)
333  // (2) If we're using random access iterators, then write the loop as
334  // a for loop with an explicit count.
335 
336  template<bool _IsMove, bool _IsSimple, typename _Category>
337  struct __copy_move
338  {
339  template<typename _II, typename _OI>
340  _GLIBCXX20_CONSTEXPR
341  static _OI
342  __copy_m(_II __first, _II __last, _OI __result)
343  {
344  for (; __first != __last; ++__result, (void)++__first)
345  *__result = *__first;
346  return __result;
347  }
348  };
349 
350 #if __cplusplus >= 201103L
351  template<typename _Category>
352  struct __copy_move<true, false, _Category>
353  {
354  template<typename _II, typename _OI>
355  _GLIBCXX20_CONSTEXPR
356  static _OI
357  __copy_m(_II __first, _II __last, _OI __result)
358  {
359  for (; __first != __last; ++__result, (void)++__first)
360  *__result = std::move(*__first);
361  return __result;
362  }
363  };
364 #endif
365 
366  template<>
367  struct __copy_move<false, false, random_access_iterator_tag>
368  {
369  template<typename _II, typename _OI>
370  _GLIBCXX20_CONSTEXPR
371  static _OI
372  __copy_m(_II __first, _II __last, _OI __result)
373  {
374  typedef typename iterator_traits<_II>::difference_type _Distance;
375  for(_Distance __n = __last - __first; __n > 0; --__n)
376  {
377  *__result = *__first;
378  ++__first;
379  ++__result;
380  }
381  return __result;
382  }
383  };
384 
385 #if __cplusplus >= 201103L
386  template<>
387  struct __copy_move<true, false, random_access_iterator_tag>
388  {
389  template<typename _II, typename _OI>
390  _GLIBCXX20_CONSTEXPR
391  static _OI
392  __copy_m(_II __first, _II __last, _OI __result)
393  {
394  typedef typename iterator_traits<_II>::difference_type _Distance;
395  for(_Distance __n = __last - __first; __n > 0; --__n)
396  {
397  *__result = std::move(*__first);
398  ++__first;
399  ++__result;
400  }
401  return __result;
402  }
403  };
404 #endif
405 
406  template<bool _IsMove>
407  struct __copy_move<_IsMove, true, random_access_iterator_tag>
408  {
409  template<typename _Tp>
410  _GLIBCXX20_CONSTEXPR
411  static _Tp*
412  __copy_m(const _Tp* __first, const _Tp* __last, _Tp* __result)
413  {
414 #if __cplusplus >= 201103L
415  using __assignable = conditional<_IsMove,
416  is_move_assignable<_Tp>,
417  is_copy_assignable<_Tp>>;
418  // trivial types can have deleted assignment
419  static_assert( __assignable::type::value, "type is not assignable" );
420 #endif
421  const ptrdiff_t _Num = __last - __first;
422  if (_Num)
423  __builtin_memmove(__result, __first, sizeof(_Tp) * _Num);
424  return __result + _Num;
425  }
426  };
427 
428  // Helpers for streambuf iterators (either istream or ostream).
429  // NB: avoid including <iosfwd>, relatively large.
430  template<typename _CharT>
431  struct char_traits;
432 
433  template<typename _CharT, typename _Traits>
434  class istreambuf_iterator;
435 
436  template<typename _CharT, typename _Traits>
437  class ostreambuf_iterator;
438 
439  template<bool _IsMove, typename _CharT>
440  typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
441  ostreambuf_iterator<_CharT, char_traits<_CharT> > >::__type
442  __copy_move_a2(_CharT*, _CharT*,
443  ostreambuf_iterator<_CharT, char_traits<_CharT> >);
444 
445  template<bool _IsMove, typename _CharT>
446  typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
447  ostreambuf_iterator<_CharT, char_traits<_CharT> > >::__type
448  __copy_move_a2(const _CharT*, const _CharT*,
449  ostreambuf_iterator<_CharT, char_traits<_CharT> >);
450 
451  template<bool _IsMove, typename _CharT>
452  typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
453  _CharT*>::__type
454  __copy_move_a2(istreambuf_iterator<_CharT, char_traits<_CharT> >,
455  istreambuf_iterator<_CharT, char_traits<_CharT> >, _CharT*);
456 
457  template<bool _IsMove, typename _II, typename _OI>
458  _GLIBCXX20_CONSTEXPR
459  inline _OI
460  __copy_move_a2(_II __first, _II __last, _OI __result)
461  {
462  typedef typename iterator_traits<_II>::iterator_category _Category;
463 #ifdef __cpp_lib_is_constant_evaluated
464  if (std::is_constant_evaluated())
465  return std::__copy_move<_IsMove, false, _Category>::
466  __copy_m(__first, __last, __result);
467 #endif
468  typedef typename iterator_traits<_II>::value_type _ValueTypeI;
469  typedef typename iterator_traits<_OI>::value_type _ValueTypeO;
470  const bool __simple = (__is_trivially_copyable(_ValueTypeI)
471  && __is_pointer<_II>::__value
472  && __is_pointer<_OI>::__value
473  && __are_same<_ValueTypeI, _ValueTypeO>::__value);
474  return std::__copy_move<_IsMove, __simple,
475  _Category>::__copy_m(__first, __last, __result);
476  }
477 
478 _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
479 
480  template<typename _Tp, typename _Ref, typename _Ptr>
482 
483 _GLIBCXX_END_NAMESPACE_CONTAINER
484 
485  template<bool _IsMove,
486  typename _Tp, typename _Ref, typename _Ptr, typename _OI>
487  _OI
488  __copy_move_a1(_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
489  _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
490  _OI);
491 
492  template<bool _IsMove,
493  typename _ITp, typename _IRef, typename _IPtr, typename _OTp>
494  _GLIBCXX_STD_C::_Deque_iterator<_OTp, _OTp&, _OTp*>
495  __copy_move_a1(_GLIBCXX_STD_C::_Deque_iterator<_ITp, _IRef, _IPtr>,
496  _GLIBCXX_STD_C::_Deque_iterator<_ITp, _IRef, _IPtr>,
497  _GLIBCXX_STD_C::_Deque_iterator<_OTp, _OTp&, _OTp*>);
498 
499  template<bool _IsMove, typename _II, typename _Tp>
500  typename __gnu_cxx::__enable_if<
501  __is_random_access_iter<_II>::__value,
502  _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*> >::__type
503  __copy_move_a1(_II, _II, _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*>);
504 
505  template<bool _IsMove, typename _II, typename _OI>
506  _GLIBCXX20_CONSTEXPR
507  inline _OI
508  __copy_move_a1(_II __first, _II __last, _OI __result)
509  { return std::__copy_move_a2<_IsMove>(__first, __last, __result); }
510 
511  template<bool _IsMove, typename _II, typename _OI>
512  _GLIBCXX20_CONSTEXPR
513  inline _OI
514  __copy_move_a(_II __first, _II __last, _OI __result)
515  {
516  return std::__niter_wrap(__result,
517  std::__copy_move_a1<_IsMove>(std::__niter_base(__first),
518  std::__niter_base(__last),
519  std::__niter_base(__result)));
520  }
521 
522  template<bool _IsMove,
523  typename _Ite, typename _Seq, typename _Cat, typename _OI>
524  _OI
525  __copy_move_a(const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
526  const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
527  _OI);
528 
529  template<bool _IsMove,
530  typename _II, typename _Ite, typename _Seq, typename _Cat>
532  __copy_move_a(_II, _II,
533  const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&);
534 
535  template<bool _IsMove,
536  typename _IIte, typename _ISeq, typename _ICat,
537  typename _OIte, typename _OSeq, typename _OCat>
539  __copy_move_a(const ::__gnu_debug::_Safe_iterator<_IIte, _ISeq, _ICat>&,
540  const ::__gnu_debug::_Safe_iterator<_IIte, _ISeq, _ICat>&,
541  const ::__gnu_debug::_Safe_iterator<_OIte, _OSeq, _OCat>&);
542 
543  /**
544  * @brief Copies the range [first,last) into result.
545  * @ingroup mutating_algorithms
546  * @param __first An input iterator.
547  * @param __last An input iterator.
548  * @param __result An output iterator.
549  * @return result + (first - last)
550  *
551  * This inline function will boil down to a call to @c memmove whenever
552  * possible. Failing that, if random access iterators are passed, then the
553  * loop count will be known (and therefore a candidate for compiler
554  * optimizations such as unrolling). Result may not be contained within
555  * [first,last); the copy_backward function should be used instead.
556  *
557  * Note that the end of the output range is permitted to be contained
558  * within [first,last).
559  */
560  template<typename _II, typename _OI>
561  _GLIBCXX20_CONSTEXPR
562  inline _OI
563  copy(_II __first, _II __last, _OI __result)
564  {
565  // concept requirements
566  __glibcxx_function_requires(_InputIteratorConcept<_II>)
567  __glibcxx_function_requires(_OutputIteratorConcept<_OI,
569  __glibcxx_requires_can_increment_range(__first, __last, __result);
570 
571  return std::__copy_move_a<__is_move_iterator<_II>::__value>
572  (std::__miter_base(__first), std::__miter_base(__last), __result);
573  }
574 
575 #if __cplusplus >= 201103L
576  /**
577  * @brief Moves the range [first,last) into result.
578  * @ingroup mutating_algorithms
579  * @param __first An input iterator.
580  * @param __last An input iterator.
581  * @param __result An output iterator.
582  * @return result + (first - last)
583  *
584  * This inline function will boil down to a call to @c memmove whenever
585  * possible. Failing that, if random access iterators are passed, then the
586  * loop count will be known (and therefore a candidate for compiler
587  * optimizations such as unrolling). Result may not be contained within
588  * [first,last); the move_backward function should be used instead.
589  *
590  * Note that the end of the output range is permitted to be contained
591  * within [first,last).
592  */
593  template<typename _II, typename _OI>
594  _GLIBCXX20_CONSTEXPR
595  inline _OI
596  move(_II __first, _II __last, _OI __result)
597  {
598  // concept requirements
599  __glibcxx_function_requires(_InputIteratorConcept<_II>)
600  __glibcxx_function_requires(_OutputIteratorConcept<_OI,
602  __glibcxx_requires_can_increment_range(__first, __last, __result);
603 
604  return std::__copy_move_a<true>(std::__miter_base(__first),
605  std::__miter_base(__last), __result);
606  }
607 
608 #define _GLIBCXX_MOVE3(_Tp, _Up, _Vp) std::move(_Tp, _Up, _Vp)
609 #else
610 #define _GLIBCXX_MOVE3(_Tp, _Up, _Vp) std::copy(_Tp, _Up, _Vp)
611 #endif
612 
613  template<bool _IsMove, bool _IsSimple, typename _Category>
614  struct __copy_move_backward
615  {
616  template<typename _BI1, typename _BI2>
617  _GLIBCXX20_CONSTEXPR
618  static _BI2
619  __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
620  {
621  while (__first != __last)
622  *--__result = *--__last;
623  return __result;
624  }
625  };
626 
627 #if __cplusplus >= 201103L
628  template<typename _Category>
629  struct __copy_move_backward<true, false, _Category>
630  {
631  template<typename _BI1, typename _BI2>
632  _GLIBCXX20_CONSTEXPR
633  static _BI2
634  __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
635  {
636  while (__first != __last)
637  *--__result = std::move(*--__last);
638  return __result;
639  }
640  };
641 #endif
642 
643  template<>
644  struct __copy_move_backward<false, false, random_access_iterator_tag>
645  {
646  template<typename _BI1, typename _BI2>
647  _GLIBCXX20_CONSTEXPR
648  static _BI2
649  __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
650  {
651  typename iterator_traits<_BI1>::difference_type
652  __n = __last - __first;
653  for (; __n > 0; --__n)
654  *--__result = *--__last;
655  return __result;
656  }
657  };
658 
659 #if __cplusplus >= 201103L
660  template<>
661  struct __copy_move_backward<true, false, random_access_iterator_tag>
662  {
663  template<typename _BI1, typename _BI2>
664  _GLIBCXX20_CONSTEXPR
665  static _BI2
666  __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
667  {
668  typename iterator_traits<_BI1>::difference_type
669  __n = __last - __first;
670  for (; __n > 0; --__n)
671  *--__result = std::move(*--__last);
672  return __result;
673  }
674  };
675 #endif
676 
677  template<bool _IsMove>
678  struct __copy_move_backward<_IsMove, true, random_access_iterator_tag>
679  {
680  template<typename _Tp>
681  _GLIBCXX20_CONSTEXPR
682  static _Tp*
683  __copy_move_b(const _Tp* __first, const _Tp* __last, _Tp* __result)
684  {
685 #if __cplusplus >= 201103L
686  using __assignable = conditional<_IsMove,
687  is_move_assignable<_Tp>,
688  is_copy_assignable<_Tp>>;
689  // trivial types can have deleted assignment
690  static_assert( __assignable::type::value, "type is not assignable" );
691 #endif
692  const ptrdiff_t _Num = __last - __first;
693  if (_Num)
694  __builtin_memmove(__result - _Num, __first, sizeof(_Tp) * _Num);
695  return __result - _Num;
696  }
697  };
698 
699  template<bool _IsMove, typename _BI1, typename _BI2>
700  _GLIBCXX20_CONSTEXPR
701  inline _BI2
702  __copy_move_backward_a2(_BI1 __first, _BI1 __last, _BI2 __result)
703  {
704  typedef typename iterator_traits<_BI1>::iterator_category _Category;
705 #ifdef __cpp_lib_is_constant_evaluated
706  if (std::is_constant_evaluated())
707  return std::__copy_move_backward<_IsMove, false, _Category>::
708  __copy_move_b(__first, __last, __result);
709 #endif
710  typedef typename iterator_traits<_BI1>::value_type _ValueType1;
711  typedef typename iterator_traits<_BI2>::value_type _ValueType2;
712  const bool __simple = (__is_trivially_copyable(_ValueType1)
713  && __is_pointer<_BI1>::__value
714  && __is_pointer<_BI2>::__value
715  && __are_same<_ValueType1, _ValueType2>::__value);
716 
717  return std::__copy_move_backward<_IsMove, __simple,
718  _Category>::__copy_move_b(__first,
719  __last,
720  __result);
721  }
722 
723  template<bool _IsMove, typename _BI1, typename _BI2>
724  _GLIBCXX20_CONSTEXPR
725  inline _BI2
726  __copy_move_backward_a1(_BI1 __first, _BI1 __last, _BI2 __result)
727  { return std::__copy_move_backward_a2<_IsMove>(__first, __last, __result); }
728 
729  template<bool _IsMove,
730  typename _Tp, typename _Ref, typename _Ptr, typename _OI>
731  _OI
732  __copy_move_backward_a1(_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
733  _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
734  _OI);
735 
736  template<bool _IsMove,
737  typename _ITp, typename _IRef, typename _IPtr, typename _OTp>
738  _GLIBCXX_STD_C::_Deque_iterator<_OTp, _OTp&, _OTp*>
739  __copy_move_backward_a1(
740  _GLIBCXX_STD_C::_Deque_iterator<_ITp, _IRef, _IPtr>,
741  _GLIBCXX_STD_C::_Deque_iterator<_ITp, _IRef, _IPtr>,
742  _GLIBCXX_STD_C::_Deque_iterator<_OTp, _OTp&, _OTp*>);
743 
744  template<bool _IsMove, typename _II, typename _Tp>
745  typename __gnu_cxx::__enable_if<
746  __is_random_access_iter<_II>::__value,
747  _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*> >::__type
748  __copy_move_backward_a1(_II, _II,
749  _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*>);
750 
751  template<bool _IsMove, typename _II, typename _OI>
752  _GLIBCXX20_CONSTEXPR
753  inline _OI
754  __copy_move_backward_a(_II __first, _II __last, _OI __result)
755  {
756  return std::__niter_wrap(__result,
757  std::__copy_move_backward_a1<_IsMove>
758  (std::__niter_base(__first), std::__niter_base(__last),
759  std::__niter_base(__result)));
760  }
761 
762  template<bool _IsMove,
763  typename _Ite, typename _Seq, typename _Cat, typename _OI>
764  _OI
765  __copy_move_backward_a(
766  const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
767  const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
768  _OI);
769 
770  template<bool _IsMove,
771  typename _II, typename _Ite, typename _Seq, typename _Cat>
773  __copy_move_backward_a(_II, _II,
774  const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&);
775 
776  template<bool _IsMove,
777  typename _IIte, typename _ISeq, typename _ICat,
778  typename _OIte, typename _OSeq, typename _OCat>
780  __copy_move_backward_a(
781  const ::__gnu_debug::_Safe_iterator<_IIte, _ISeq, _ICat>&,
782  const ::__gnu_debug::_Safe_iterator<_IIte, _ISeq, _ICat>&,
783  const ::__gnu_debug::_Safe_iterator<_OIte, _OSeq, _OCat>&);
784 
785  /**
786  * @brief Copies the range [first,last) into result.
787  * @ingroup mutating_algorithms
788  * @param __first A bidirectional iterator.
789  * @param __last A bidirectional iterator.
790  * @param __result A bidirectional iterator.
791  * @return result - (first - last)
792  *
793  * The function has the same effect as copy, but starts at the end of the
794  * range and works its way to the start, returning the start of the result.
795  * This inline function will boil down to a call to @c memmove whenever
796  * possible. Failing that, if random access iterators are passed, then the
797  * loop count will be known (and therefore a candidate for compiler
798  * optimizations such as unrolling).
799  *
800  * Result may not be in the range (first,last]. Use copy instead. Note
801  * that the start of the output range may overlap [first,last).
802  */
803  template<typename _BI1, typename _BI2>
804  _GLIBCXX20_CONSTEXPR
805  inline _BI2
806  copy_backward(_BI1 __first, _BI1 __last, _BI2 __result)
807  {
808  // concept requirements
809  __glibcxx_function_requires(_BidirectionalIteratorConcept<_BI1>)
810  __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<_BI2>)
811  __glibcxx_function_requires(_ConvertibleConcept<
814  __glibcxx_requires_can_decrement_range(__first, __last, __result);
815 
816  return std::__copy_move_backward_a<__is_move_iterator<_BI1>::__value>
817  (std::__miter_base(__first), std::__miter_base(__last), __result);
818  }
819 
820 #if __cplusplus >= 201103L
821  /**
822  * @brief Moves the range [first,last) into result.
823  * @ingroup mutating_algorithms
824  * @param __first A bidirectional iterator.
825  * @param __last A bidirectional iterator.
826  * @param __result A bidirectional iterator.
827  * @return result - (first - last)
828  *
829  * The function has the same effect as move, but starts at the end of the
830  * range and works its way to the start, returning the start of the result.
831  * This inline function will boil down to a call to @c memmove whenever
832  * possible. Failing that, if random access iterators are passed, then the
833  * loop count will be known (and therefore a candidate for compiler
834  * optimizations such as unrolling).
835  *
836  * Result may not be in the range (first,last]. Use move instead. Note
837  * that the start of the output range may overlap [first,last).
838  */
839  template<typename _BI1, typename _BI2>
840  _GLIBCXX20_CONSTEXPR
841  inline _BI2
842  move_backward(_BI1 __first, _BI1 __last, _BI2 __result)
843  {
844  // concept requirements
845  __glibcxx_function_requires(_BidirectionalIteratorConcept<_BI1>)
846  __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<_BI2>)
847  __glibcxx_function_requires(_ConvertibleConcept<
850  __glibcxx_requires_can_decrement_range(__first, __last, __result);
851 
852  return std::__copy_move_backward_a<true>(std::__miter_base(__first),
853  std::__miter_base(__last),
854  __result);
855  }
856 
857 #define _GLIBCXX_MOVE_BACKWARD3(_Tp, _Up, _Vp) std::move_backward(_Tp, _Up, _Vp)
858 #else
859 #define _GLIBCXX_MOVE_BACKWARD3(_Tp, _Up, _Vp) std::copy_backward(_Tp, _Up, _Vp)
860 #endif
861 
862  template<typename _ForwardIterator, typename _Tp>
863  _GLIBCXX20_CONSTEXPR
864  inline typename
865  __gnu_cxx::__enable_if<!__is_scalar<_Tp>::__value, void>::__type
866  __fill_a1(_ForwardIterator __first, _ForwardIterator __last,
867  const _Tp& __value)
868  {
869  for (; __first != __last; ++__first)
870  *__first = __value;
871  }
872 
873  template<typename _ForwardIterator, typename _Tp>
874  _GLIBCXX20_CONSTEXPR
875  inline typename
876  __gnu_cxx::__enable_if<__is_scalar<_Tp>::__value, void>::__type
877  __fill_a1(_ForwardIterator __first, _ForwardIterator __last,
878  const _Tp& __value)
879  {
880  const _Tp __tmp = __value;
881  for (; __first != __last; ++__first)
882  *__first = __tmp;
883  }
884 
885  // Specialization: for char types we can use memset.
886  template<typename _Tp>
887  inline typename
888  __gnu_cxx::__enable_if<__is_byte<_Tp>::__value, void>::__type
889  __fill_a1(_Tp* __first, _Tp* __last, const _Tp& __c)
890  {
891  const _Tp __tmp = __c;
892  if (const size_t __len = __last - __first)
893  __builtin_memset(__first, static_cast<unsigned char>(__tmp), __len);
894  }
895 
896  template<typename _Ite, typename _Cont, typename _Tp>
897  _GLIBCXX20_CONSTEXPR
898  inline void
899  __fill_a1(::__gnu_cxx::__normal_iterator<_Ite, _Cont> __first,
900  ::__gnu_cxx::__normal_iterator<_Ite, _Cont> __last,
901  const _Tp& __value)
902  { std::__fill_a1(__first.base(), __last.base(), __value); }
903 
904  template<typename _Tp, typename _VTp>
905  void
906  __fill_a1(const _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*>&,
907  const _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*>&,
908  const _VTp&);
909 
910  template<typename _FIte, typename _Tp>
911  _GLIBCXX20_CONSTEXPR
912  inline void
913  __fill_a(_FIte __first, _FIte __last, const _Tp& __value)
914  { std::__fill_a1(__first, __last, __value); }
915 
916  template<typename _Ite, typename _Seq, typename _Cat, typename _Tp>
917  void
918  __fill_a(const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
919  const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
920  const _Tp&);
921 
922  /**
923  * @brief Fills the range [first,last) with copies of value.
924  * @ingroup mutating_algorithms
925  * @param __first A forward iterator.
926  * @param __last A forward iterator.
927  * @param __value A reference-to-const of arbitrary type.
928  * @return Nothing.
929  *
930  * This function fills a range with copies of the same value. For char
931  * types filling contiguous areas of memory, this becomes an inline call
932  * to @c memset or @c wmemset.
933  */
934  template<typename _ForwardIterator, typename _Tp>
935  _GLIBCXX20_CONSTEXPR
936  inline void
937  fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value)
938  {
939  // concept requirements
940  __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
941  _ForwardIterator>)
942  __glibcxx_requires_valid_range(__first, __last);
943 
944  std::__fill_a(__first, __last, __value);
945  }
946 
947  // Used by fill_n, generate_n, etc. to convert _Size to an integral type:
948  inline _GLIBCXX_CONSTEXPR int
949  __size_to_integer(int __n) { return __n; }
950  inline _GLIBCXX_CONSTEXPR unsigned
951  __size_to_integer(unsigned __n) { return __n; }
952  inline _GLIBCXX_CONSTEXPR long
953  __size_to_integer(long __n) { return __n; }
954  inline _GLIBCXX_CONSTEXPR unsigned long
955  __size_to_integer(unsigned long __n) { return __n; }
956  inline _GLIBCXX_CONSTEXPR long long
957  __size_to_integer(long long __n) { return __n; }
958  inline _GLIBCXX_CONSTEXPR unsigned long long
959  __size_to_integer(unsigned long long __n) { return __n; }
960 
961 #if defined(__GLIBCXX_TYPE_INT_N_0)
962  inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_0
963  __size_to_integer(__GLIBCXX_TYPE_INT_N_0 __n) { return __n; }
964  inline _GLIBCXX_CONSTEXPR unsigned __GLIBCXX_TYPE_INT_N_0
965  __size_to_integer(unsigned __GLIBCXX_TYPE_INT_N_0 __n) { return __n; }
966 #endif
967 #if defined(__GLIBCXX_TYPE_INT_N_1)
968  inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_1
969  __size_to_integer(__GLIBCXX_TYPE_INT_N_1 __n) { return __n; }
970  inline _GLIBCXX_CONSTEXPR unsigned __GLIBCXX_TYPE_INT_N_1
971  __size_to_integer(unsigned __GLIBCXX_TYPE_INT_N_1 __n) { return __n; }
972 #endif
973 #if defined(__GLIBCXX_TYPE_INT_N_2)
974  inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_2
975  __size_to_integer(__GLIBCXX_TYPE_INT_N_2 __n) { return __n; }
976  inline _GLIBCXX_CONSTEXPR unsigned __GLIBCXX_TYPE_INT_N_2
977  __size_to_integer(unsigned __GLIBCXX_TYPE_INT_N_2 __n) { return __n; }
978 #endif
979 #if defined(__GLIBCXX_TYPE_INT_N_3)
980  inline _GLIBCXX_CONSTEXPR unsigned __GLIBCXX_TYPE_INT_N_3
981  __size_to_integer(__GLIBCXX_TYPE_INT_N_3 __n) { return __n; }
982  inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_3
983  __size_to_integer(unsigned __GLIBCXX_TYPE_INT_N_3 __n) { return __n; }
984 #endif
985 
986  inline _GLIBCXX_CONSTEXPR long long
987  __size_to_integer(float __n) { return __n; }
988  inline _GLIBCXX_CONSTEXPR long long
989  __size_to_integer(double __n) { return __n; }
990  inline _GLIBCXX_CONSTEXPR long long
991  __size_to_integer(long double __n) { return __n; }
992 #if !defined(__STRICT_ANSI__) && defined(_GLIBCXX_USE_FLOAT128)
993  inline _GLIBCXX_CONSTEXPR long long
994  __size_to_integer(__float128 __n) { return __n; }
995 #endif
996 
997  template<typename _OutputIterator, typename _Size, typename _Tp>
998  _GLIBCXX20_CONSTEXPR
999  inline typename
1000  __gnu_cxx::__enable_if<!__is_scalar<_Tp>::__value, _OutputIterator>::__type
1001  __fill_n_a1(_OutputIterator __first, _Size __n, const _Tp& __value)
1002  {
1003  for (; __n > 0; --__n, (void) ++__first)
1004  *__first = __value;
1005  return __first;
1006  }
1007 
1008  template<typename _OutputIterator, typename _Size, typename _Tp>
1009  _GLIBCXX20_CONSTEXPR
1010  inline typename
1011  __gnu_cxx::__enable_if<__is_scalar<_Tp>::__value, _OutputIterator>::__type
1012  __fill_n_a1(_OutputIterator __first, _Size __n, const _Tp& __value)
1013  {
1014  const _Tp __tmp = __value;
1015  for (; __n > 0; --__n, (void) ++__first)
1016  *__first = __tmp;
1017  return __first;
1018  }
1019 
1020  template<typename _Ite, typename _Seq, typename _Cat, typename _Size,
1021  typename _Tp>
1023  __fill_n_a(const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>& __first,
1024  _Size __n, const _Tp& __value,
1026 
1027  template<typename _OutputIterator, typename _Size, typename _Tp>
1028  _GLIBCXX20_CONSTEXPR
1029  inline _OutputIterator
1030  __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value,
1032  {
1033 #if __cplusplus >= 201103L
1034  static_assert(is_integral<_Size>{}, "fill_n must pass integral size");
1035 #endif
1036  return __fill_n_a1(__first, __n, __value);
1037  }
1038 
1039  template<typename _OutputIterator, typename _Size, typename _Tp>
1040  _GLIBCXX20_CONSTEXPR
1041  inline _OutputIterator
1042  __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value,
1044  {
1045 #if __cplusplus >= 201103L
1046  static_assert(is_integral<_Size>{}, "fill_n must pass integral size");
1047 #endif
1048  return __fill_n_a1(__first, __n, __value);
1049  }
1050 
1051  template<typename _OutputIterator, typename _Size, typename _Tp>
1052  _GLIBCXX20_CONSTEXPR
1053  inline _OutputIterator
1054  __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value,
1056  {
1057 #if __cplusplus >= 201103L
1058  static_assert(is_integral<_Size>{}, "fill_n must pass integral size");
1059 #endif
1060  if (__n <= 0)
1061  return __first;
1062 
1063  __glibcxx_requires_can_increment(__first, __n);
1064 
1065  std::__fill_a(__first, __first + __n, __value);
1066  return __first + __n;
1067  }
1068 
1069  /**
1070  * @brief Fills the range [first,first+n) with copies of value.
1071  * @ingroup mutating_algorithms
1072  * @param __first An output iterator.
1073  * @param __n The count of copies to perform.
1074  * @param __value A reference-to-const of arbitrary type.
1075  * @return The iterator at first+n.
1076  *
1077  * This function fills a range with copies of the same value. For char
1078  * types filling contiguous areas of memory, this becomes an inline call
1079  * to @c memset or @c wmemset.
1080  *
1081  * If @p __n is negative, the function does nothing.
1082  */
1083  // _GLIBCXX_RESOLVE_LIB_DEFECTS
1084  // DR 865. More algorithms that throw away information
1085  // DR 426. search_n(), fill_n(), and generate_n() with negative n
1086  template<typename _OI, typename _Size, typename _Tp>
1087  _GLIBCXX20_CONSTEXPR
1088  inline _OI
1089  fill_n(_OI __first, _Size __n, const _Tp& __value)
1090  {
1091  // concept requirements
1092  __glibcxx_function_requires(_OutputIteratorConcept<_OI, _Tp>)
1093 
1094  return std::__fill_n_a(__first, std::__size_to_integer(__n), __value,
1095  std::__iterator_category(__first));
1096  }
1097 
1098  template<bool _BoolType>
1099  struct __equal
1100  {
1101  template<typename _II1, typename _II2>
1102  _GLIBCXX20_CONSTEXPR
1103  static bool
1104  equal(_II1 __first1, _II1 __last1, _II2 __first2)
1105  {
1106  for (; __first1 != __last1; ++__first1, (void) ++__first2)
1107  if (!(*__first1 == *__first2))
1108  return false;
1109  return true;
1110  }
1111  };
1112 
1113  template<>
1114  struct __equal<true>
1115  {
1116  template<typename _Tp>
1117  _GLIBCXX20_CONSTEXPR
1118  static bool
1119  equal(const _Tp* __first1, const _Tp* __last1, const _Tp* __first2)
1120  {
1121  if (const size_t __len = (__last1 - __first1))
1122  return !std::__memcmp(__first1, __first2, __len);
1123  return true;
1124  }
1125  };
1126 
1127  template<typename _Tp, typename _Ref, typename _Ptr, typename _II>
1128  typename __gnu_cxx::__enable_if<
1129  __is_random_access_iter<_II>::__value, bool>::__type
1130  __equal_aux1(_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
1131  _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
1132  _II);
1133 
1134  template<typename _Tp1, typename _Ref1, typename _Ptr1,
1135  typename _Tp2, typename _Ref2, typename _Ptr2>
1136  bool
1137  __equal_aux1(_GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
1138  _GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
1139  _GLIBCXX_STD_C::_Deque_iterator<_Tp2, _Ref2, _Ptr2>);
1140 
1141  template<typename _II, typename _Tp, typename _Ref, typename _Ptr>
1142  typename __gnu_cxx::__enable_if<
1143  __is_random_access_iter<_II>::__value, bool>::__type
1144  __equal_aux1(_II, _II,
1145  _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>);
1146 
1147  template<typename _II1, typename _II2>
1148  _GLIBCXX20_CONSTEXPR
1149  inline bool
1150  __equal_aux1(_II1 __first1, _II1 __last1, _II2 __first2)
1151  {
1152  typedef typename iterator_traits<_II1>::value_type _ValueType1;
1153  typedef typename iterator_traits<_II2>::value_type _ValueType2;
1154  const bool __simple = ((__is_integer<_ValueType1>::__value
1155  || __is_pointer<_ValueType1>::__value)
1156  && __is_pointer<_II1>::__value
1157  && __is_pointer<_II2>::__value
1158  && __are_same<_ValueType1, _ValueType2>::__value);
1159 
1160  return std::__equal<__simple>::equal(__first1, __last1, __first2);
1161  }
1162 
1163  template<typename _II1, typename _II2>
1164  _GLIBCXX20_CONSTEXPR
1165  inline bool
1166  __equal_aux(_II1 __first1, _II1 __last1, _II2 __first2)
1167  {
1168  return std::__equal_aux1(std::__niter_base(__first1),
1169  std::__niter_base(__last1),
1170  std::__niter_base(__first2));
1171  }
1172 
1173  template<typename _II1, typename _Seq1, typename _Cat1, typename _II2>
1174  bool
1175  __equal_aux(const ::__gnu_debug::_Safe_iterator<_II1, _Seq1, _Cat1>&,
1176  const ::__gnu_debug::_Safe_iterator<_II1, _Seq1, _Cat1>&,
1177  _II2);
1178 
1179  template<typename _II1, typename _II2, typename _Seq2, typename _Cat2>
1180  bool
1181  __equal_aux(_II1, _II1,
1182  const ::__gnu_debug::_Safe_iterator<_II2, _Seq2, _Cat2>&);
1183 
1184  template<typename _II1, typename _Seq1, typename _Cat1,
1185  typename _II2, typename _Seq2, typename _Cat2>
1186  bool
1187  __equal_aux(const ::__gnu_debug::_Safe_iterator<_II1, _Seq1, _Cat1>&,
1188  const ::__gnu_debug::_Safe_iterator<_II1, _Seq1, _Cat1>&,
1189  const ::__gnu_debug::_Safe_iterator<_II2, _Seq2, _Cat2>&);
1190 
1191  template<typename, typename>
1192  struct __lc_rai
1193  {
1194  template<typename _II1, typename _II2>
1195  _GLIBCXX20_CONSTEXPR
1196  static _II1
1197  __newlast1(_II1, _II1 __last1, _II2, _II2)
1198  { return __last1; }
1199 
1200  template<typename _II>
1201  _GLIBCXX20_CONSTEXPR
1202  static bool
1203  __cnd2(_II __first, _II __last)
1204  { return __first != __last; }
1205  };
1206 
1207  template<>
1208  struct __lc_rai<random_access_iterator_tag, random_access_iterator_tag>
1209  {
1210  template<typename _RAI1, typename _RAI2>
1211  _GLIBCXX20_CONSTEXPR
1212  static _RAI1
1213  __newlast1(_RAI1 __first1, _RAI1 __last1,
1214  _RAI2 __first2, _RAI2 __last2)
1215  {
1216  const typename iterator_traits<_RAI1>::difference_type
1217  __diff1 = __last1 - __first1;
1218  const typename iterator_traits<_RAI2>::difference_type
1219  __diff2 = __last2 - __first2;
1220  return __diff2 < __diff1 ? __first1 + __diff2 : __last1;
1221  }
1222 
1223  template<typename _RAI>
1224  static _GLIBCXX20_CONSTEXPR bool
1225  __cnd2(_RAI, _RAI)
1226  { return true; }
1227  };
1228 
1229  template<typename _II1, typename _II2, typename _Compare>
1230  _GLIBCXX20_CONSTEXPR
1231  bool
1232  __lexicographical_compare_impl(_II1 __first1, _II1 __last1,
1233  _II2 __first2, _II2 __last2,
1234  _Compare __comp)
1235  {
1236  typedef typename iterator_traits<_II1>::iterator_category _Category1;
1237  typedef typename iterator_traits<_II2>::iterator_category _Category2;
1238  typedef std::__lc_rai<_Category1, _Category2> __rai_type;
1239 
1240  __last1 = __rai_type::__newlast1(__first1, __last1, __first2, __last2);
1241  for (; __first1 != __last1 && __rai_type::__cnd2(__first2, __last2);
1242  ++__first1, (void)++__first2)
1243  {
1244  if (__comp(__first1, __first2))
1245  return true;
1246  if (__comp(__first2, __first1))
1247  return false;
1248  }
1249  return __first1 == __last1 && __first2 != __last2;
1250  }
1251 
1252  template<bool _BoolType>
1253  struct __lexicographical_compare
1254  {
1255  template<typename _II1, typename _II2>
1256  _GLIBCXX20_CONSTEXPR
1257  static bool
1258  __lc(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
1259  {
1260  using __gnu_cxx::__ops::__iter_less_iter;
1261  return std::__lexicographical_compare_impl(__first1, __last1,
1262  __first2, __last2,
1263  __iter_less_iter());
1264  }
1265  };
1266 
1267  template<>
1268  struct __lexicographical_compare<true>
1269  {
1270  template<typename _Tp, typename _Up>
1271  _GLIBCXX20_CONSTEXPR
1272  static bool
1273  __lc(const _Tp* __first1, const _Tp* __last1,
1274  const _Up* __first2, const _Up* __last2)
1275  {
1276  const size_t __len1 = __last1 - __first1;
1277  const size_t __len2 = __last2 - __first2;
1278  if (const size_t __len = std::min(__len1, __len2))
1279  if (int __result = std::__memcmp(__first1, __first2, __len))
1280  return __result < 0;
1281  return __len1 < __len2;
1282  }
1283  };
1284 
1285  template<typename _II1, typename _II2>
1286  _GLIBCXX20_CONSTEXPR
1287  inline bool
1288  __lexicographical_compare_aux(_II1 __first1, _II1 __last1,
1289  _II2 __first2, _II2 __last2)
1290  {
1291  typedef typename iterator_traits<_II1>::value_type _ValueType1;
1292  typedef typename iterator_traits<_II2>::value_type _ValueType2;
1293  const bool __simple =
1294  (__is_byte<_ValueType1>::__value && __is_byte<_ValueType2>::__value
1295  && !__gnu_cxx::__numeric_traits<_ValueType1>::__is_signed
1296  && !__gnu_cxx::__numeric_traits<_ValueType2>::__is_signed
1297  && __is_pointer<_II1>::__value
1298  && __is_pointer<_II2>::__value);
1299 
1300  return std::__lexicographical_compare<__simple>::__lc(__first1, __last1,
1301  __first2, __last2);
1302  }
1303 
1304  template<typename _ForwardIterator, typename _Tp, typename _Compare>
1305  _GLIBCXX20_CONSTEXPR
1306  _ForwardIterator
1307  __lower_bound(_ForwardIterator __first, _ForwardIterator __last,
1308  const _Tp& __val, _Compare __comp)
1309  {
1310  typedef typename iterator_traits<_ForwardIterator>::difference_type
1311  _DistanceType;
1312 
1313  _DistanceType __len = std::distance(__first, __last);
1314 
1315  while (__len > 0)
1316  {
1317  _DistanceType __half = __len >> 1;
1318  _ForwardIterator __middle = __first;
1319  std::advance(__middle, __half);
1320  if (__comp(__middle, __val))
1321  {
1322  __first = __middle;
1323  ++__first;
1324  __len = __len - __half - 1;
1325  }
1326  else
1327  __len = __half;
1328  }
1329  return __first;
1330  }
1331 
1332  /**
1333  * @brief Finds the first position in which @a val could be inserted
1334  * without changing the ordering.
1335  * @param __first An iterator.
1336  * @param __last Another iterator.
1337  * @param __val The search term.
1338  * @return An iterator pointing to the first element <em>not less
1339  * than</em> @a val, or end() if every element is less than
1340  * @a val.
1341  * @ingroup binary_search_algorithms
1342  */
1343  template<typename _ForwardIterator, typename _Tp>
1344  _GLIBCXX20_CONSTEXPR
1345  inline _ForwardIterator
1346  lower_bound(_ForwardIterator __first, _ForwardIterator __last,
1347  const _Tp& __val)
1348  {
1349  // concept requirements
1350  __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
1351  __glibcxx_function_requires(_LessThanOpConcept<
1353  __glibcxx_requires_partitioned_lower(__first, __last, __val);
1354 
1355  return std::__lower_bound(__first, __last, __val,
1356  __gnu_cxx::__ops::__iter_less_val());
1357  }
1358 
1359  /// This is a helper function for the sort routines and for random.tcc.
1360  // Precondition: __n > 0.
1361  inline _GLIBCXX_CONSTEXPR int
1362  __lg(int __n)
1363  { return (int)sizeof(int) * __CHAR_BIT__ - 1 - __builtin_clz(__n); }
1364 
1365  inline _GLIBCXX_CONSTEXPR unsigned
1366  __lg(unsigned __n)
1367  { return (int)sizeof(int) * __CHAR_BIT__ - 1 - __builtin_clz(__n); }
1368 
1369  inline _GLIBCXX_CONSTEXPR long
1370  __lg(long __n)
1371  { return (int)sizeof(long) * __CHAR_BIT__ - 1 - __builtin_clzl(__n); }
1372 
1373  inline _GLIBCXX_CONSTEXPR unsigned long
1374  __lg(unsigned long __n)
1375  { return (int)sizeof(long) * __CHAR_BIT__ - 1 - __builtin_clzl(__n); }
1376 
1377  inline _GLIBCXX_CONSTEXPR long long
1378  __lg(long long __n)
1379  { return (int)sizeof(long long) * __CHAR_BIT__ - 1 - __builtin_clzll(__n); }
1380 
1381  inline _GLIBCXX_CONSTEXPR unsigned long long
1382  __lg(unsigned long long __n)
1383  { return (int)sizeof(long long) * __CHAR_BIT__ - 1 - __builtin_clzll(__n); }
1384 
1385 _GLIBCXX_BEGIN_NAMESPACE_ALGO
1386 
1387  /**
1388  * @brief Tests a range for element-wise equality.
1389  * @ingroup non_mutating_algorithms
1390  * @param __first1 An input iterator.
1391  * @param __last1 An input iterator.
1392  * @param __first2 An input iterator.
1393  * @return A boolean true or false.
1394  *
1395  * This compares the elements of two ranges using @c == and returns true or
1396  * false depending on whether all of the corresponding elements of the
1397  * ranges are equal.
1398  */
1399  template<typename _II1, typename _II2>
1400  _GLIBCXX20_CONSTEXPR
1401  inline bool
1402  equal(_II1 __first1, _II1 __last1, _II2 __first2)
1403  {
1404  // concept requirements
1405  __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1406  __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1407  __glibcxx_function_requires(_EqualOpConcept<
1410  __glibcxx_requires_can_increment_range(__first1, __last1, __first2);
1411 
1412  return std::__equal_aux(__first1, __last1, __first2);
1413  }
1414 
1415  /**
1416  * @brief Tests a range for element-wise equality.
1417  * @ingroup non_mutating_algorithms
1418  * @param __first1 An input iterator.
1419  * @param __last1 An input iterator.
1420  * @param __first2 An input iterator.
1421  * @param __binary_pred A binary predicate @link functors
1422  * functor@endlink.
1423  * @return A boolean true or false.
1424  *
1425  * This compares the elements of two ranges using the binary_pred
1426  * parameter, and returns true or
1427  * false depending on whether all of the corresponding elements of the
1428  * ranges are equal.
1429  */
1430  template<typename _IIter1, typename _IIter2, typename _BinaryPredicate>
1431  _GLIBCXX20_CONSTEXPR
1432  inline bool
1433  equal(_IIter1 __first1, _IIter1 __last1,
1434  _IIter2 __first2, _BinaryPredicate __binary_pred)
1435  {
1436  // concept requirements
1437  __glibcxx_function_requires(_InputIteratorConcept<_IIter1>)
1438  __glibcxx_function_requires(_InputIteratorConcept<_IIter2>)
1439  __glibcxx_requires_valid_range(__first1, __last1);
1440 
1441  for (; __first1 != __last1; ++__first1, (void)++__first2)
1442  if (!bool(__binary_pred(*__first1, *__first2)))
1443  return false;
1444  return true;
1445  }
1446 
1447 #if __cplusplus >= 201103L
1448  // 4-iterator version of std::equal<It1, It2> for use in C++11.
1449  template<typename _II1, typename _II2>
1450  _GLIBCXX20_CONSTEXPR
1451  inline bool
1452  __equal4(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
1453  {
1454  using _RATag = random_access_iterator_tag;
1455  using _Cat1 = typename iterator_traits<_II1>::iterator_category;
1456  using _Cat2 = typename iterator_traits<_II2>::iterator_category;
1457  using _RAIters = __and_<is_same<_Cat1, _RATag>, is_same<_Cat2, _RATag>>;
1458  if (_RAIters())
1459  {
1460  auto __d1 = std::distance(__first1, __last1);
1461  auto __d2 = std::distance(__first2, __last2);
1462  if (__d1 != __d2)
1463  return false;
1464  return _GLIBCXX_STD_A::equal(__first1, __last1, __first2);
1465  }
1466 
1467  for (; __first1 != __last1 && __first2 != __last2;
1468  ++__first1, (void)++__first2)
1469  if (!(*__first1 == *__first2))
1470  return false;
1471  return __first1 == __last1 && __first2 == __last2;
1472  }
1473 
1474  // 4-iterator version of std::equal<It1, It2, BinaryPred> for use in C++11.
1475  template<typename _II1, typename _II2, typename _BinaryPredicate>
1476  _GLIBCXX20_CONSTEXPR
1477  inline bool
1478  __equal4(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2,
1479  _BinaryPredicate __binary_pred)
1480  {
1481  using _RATag = random_access_iterator_tag;
1482  using _Cat1 = typename iterator_traits<_II1>::iterator_category;
1483  using _Cat2 = typename iterator_traits<_II2>::iterator_category;
1484  using _RAIters = __and_<is_same<_Cat1, _RATag>, is_same<_Cat2, _RATag>>;
1485  if (_RAIters())
1486  {
1487  auto __d1 = std::distance(__first1, __last1);
1488  auto __d2 = std::distance(__first2, __last2);
1489  if (__d1 != __d2)
1490  return false;
1491  return _GLIBCXX_STD_A::equal(__first1, __last1, __first2,
1492  __binary_pred);
1493  }
1494 
1495  for (; __first1 != __last1 && __first2 != __last2;
1496  ++__first1, (void)++__first2)
1497  if (!bool(__binary_pred(*__first1, *__first2)))
1498  return false;
1499  return __first1 == __last1 && __first2 == __last2;
1500  }
1501 #endif // C++11
1502 
1503 #if __cplusplus > 201103L
1504 
1505 #define __cpp_lib_robust_nonmodifying_seq_ops 201304
1506 
1507  /**
1508  * @brief Tests a range for element-wise equality.
1509  * @ingroup non_mutating_algorithms
1510  * @param __first1 An input iterator.
1511  * @param __last1 An input iterator.
1512  * @param __first2 An input iterator.
1513  * @param __last2 An input iterator.
1514  * @return A boolean true or false.
1515  *
1516  * This compares the elements of two ranges using @c == and returns true or
1517  * false depending on whether all of the corresponding elements of the
1518  * ranges are equal.
1519  */
1520  template<typename _II1, typename _II2>
1521  _GLIBCXX20_CONSTEXPR
1522  inline bool
1523  equal(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
1524  {
1525  // concept requirements
1526  __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1527  __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1528  __glibcxx_function_requires(_EqualOpConcept<
1531  __glibcxx_requires_valid_range(__first1, __last1);
1532  __glibcxx_requires_valid_range(__first2, __last2);
1533 
1534  return _GLIBCXX_STD_A::__equal4(__first1, __last1, __first2, __last2);
1535  }
1536 
1537  /**
1538  * @brief Tests a range for element-wise equality.
1539  * @ingroup non_mutating_algorithms
1540  * @param __first1 An input iterator.
1541  * @param __last1 An input iterator.
1542  * @param __first2 An input iterator.
1543  * @param __last2 An input iterator.
1544  * @param __binary_pred A binary predicate @link functors
1545  * functor@endlink.
1546  * @return A boolean true or false.
1547  *
1548  * This compares the elements of two ranges using the binary_pred
1549  * parameter, and returns true or
1550  * false depending on whether all of the corresponding elements of the
1551  * ranges are equal.
1552  */
1553  template<typename _IIter1, typename _IIter2, typename _BinaryPredicate>
1554  _GLIBCXX20_CONSTEXPR
1555  inline bool
1556  equal(_IIter1 __first1, _IIter1 __last1,
1557  _IIter2 __first2, _IIter2 __last2, _BinaryPredicate __binary_pred)
1558  {
1559  // concept requirements
1560  __glibcxx_function_requires(_InputIteratorConcept<_IIter1>)
1561  __glibcxx_function_requires(_InputIteratorConcept<_IIter2>)
1562  __glibcxx_requires_valid_range(__first1, __last1);
1563  __glibcxx_requires_valid_range(__first2, __last2);
1564 
1565  return _GLIBCXX_STD_A::__equal4(__first1, __last1, __first2, __last2,
1566  __binary_pred);
1567  }
1568 #endif // C++14
1569 
1570  /**
1571  * @brief Performs @b dictionary comparison on ranges.
1572  * @ingroup sorting_algorithms
1573  * @param __first1 An input iterator.
1574  * @param __last1 An input iterator.
1575  * @param __first2 An input iterator.
1576  * @param __last2 An input iterator.
1577  * @return A boolean true or false.
1578  *
1579  * <em>Returns true if the sequence of elements defined by the range
1580  * [first1,last1) is lexicographically less than the sequence of elements
1581  * defined by the range [first2,last2). Returns false otherwise.</em>
1582  * (Quoted from [25.3.8]/1.) If the iterators are all character pointers,
1583  * then this is an inline call to @c memcmp.
1584  */
1585  template<typename _II1, typename _II2>
1586  _GLIBCXX20_CONSTEXPR
1587  inline bool
1588  lexicographical_compare(_II1 __first1, _II1 __last1,
1589  _II2 __first2, _II2 __last2)
1590  {
1591 #ifdef _GLIBCXX_CONCEPT_CHECKS
1592  // concept requirements
1593  typedef typename iterator_traits<_II1>::value_type _ValueType1;
1594  typedef typename iterator_traits<_II2>::value_type _ValueType2;
1595 #endif
1596  __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1597  __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1598  __glibcxx_function_requires(_LessThanOpConcept<_ValueType1, _ValueType2>)
1599  __glibcxx_function_requires(_LessThanOpConcept<_ValueType2, _ValueType1>)
1600  __glibcxx_requires_valid_range(__first1, __last1);
1601  __glibcxx_requires_valid_range(__first2, __last2);
1602 
1603  return std::__lexicographical_compare_aux(std::__niter_base(__first1),
1604  std::__niter_base(__last1),
1605  std::__niter_base(__first2),
1606  std::__niter_base(__last2));
1607  }
1608 
1609  /**
1610  * @brief Performs @b dictionary comparison on ranges.
1611  * @ingroup sorting_algorithms
1612  * @param __first1 An input iterator.
1613  * @param __last1 An input iterator.
1614  * @param __first2 An input iterator.
1615  * @param __last2 An input iterator.
1616  * @param __comp A @link comparison_functors comparison functor@endlink.
1617  * @return A boolean true or false.
1618  *
1619  * The same as the four-parameter @c lexicographical_compare, but uses the
1620  * comp parameter instead of @c <.
1621  */
1622  template<typename _II1, typename _II2, typename _Compare>
1623  _GLIBCXX20_CONSTEXPR
1624  inline bool
1625  lexicographical_compare(_II1 __first1, _II1 __last1,
1626  _II2 __first2, _II2 __last2, _Compare __comp)
1627  {
1628  // concept requirements
1629  __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1630  __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1631  __glibcxx_requires_valid_range(__first1, __last1);
1632  __glibcxx_requires_valid_range(__first2, __last2);
1633 
1634  return std::__lexicographical_compare_impl
1635  (__first1, __last1, __first2, __last2,
1636  __gnu_cxx::__ops::__iter_comp_iter(__comp));
1637  }
1638 
1639 #if __cpp_lib_three_way_comparison
1640  // Iter points to a contiguous range of unsigned narrow character type
1641  // or std::byte, suitable for comparison by memcmp.
1642  template<typename _Iter>
1643  concept __is_byte_iter = contiguous_iterator<_Iter>
1644  && __is_byte<iter_value_t<_Iter>>::__value != 0
1645  && !__gnu_cxx::__numeric_traits<iter_value_t<_Iter>>::__is_signed;
1646 
1647  // Return a struct with two members, initialized to the smaller of x and y
1648  // (or x if they compare equal) and the result of the comparison x <=> y.
1649  template<typename _Tp>
1650  constexpr auto
1651  __min_cmp(_Tp __x, _Tp __y)
1652  {
1653  struct _Res {
1654  _Tp _M_min;
1655  decltype(__x <=> __y) _M_cmp;
1656  };
1657  auto __c = __x <=> __y;
1658  if (__c > 0)
1659  return _Res{__y, __c};
1660  return _Res{__x, __c};
1661  }
1662 
1663  /**
1664  * @brief Performs dictionary comparison on ranges.
1665  * @ingroup sorting_algorithms
1666  * @param __first1 An input iterator.
1667  * @param __last1 An input iterator.
1668  * @param __first2 An input iterator.
1669  * @param __last2 An input iterator.
1670  * @param __comp A @link comparison_functors comparison functor@endlink.
1671  * @return The comparison category that `__comp(*__first1, *__first2)`
1672  * returns.
1673  */
1674  template<typename _InputIter1, typename _InputIter2, typename _Comp>
1675  constexpr auto
1676  lexicographical_compare_three_way(_InputIter1 __first1,
1677  _InputIter1 __last1,
1678  _InputIter2 __first2,
1679  _InputIter2 __last2,
1680  _Comp __comp)
1681  -> decltype(__comp(*__first1, *__first2))
1682  {
1683  // concept requirements
1684  __glibcxx_function_requires(_InputIteratorConcept<_InputIter1>)
1685  __glibcxx_function_requires(_InputIteratorConcept<_InputIter2>)
1686  __glibcxx_requires_valid_range(__first1, __last1);
1687  __glibcxx_requires_valid_range(__first2, __last2);
1688 
1689 #if __cpp_lib_is_constant_evaluated
1690  using _Cat = decltype(__comp(*__first1, *__first2));
1691  static_assert(same_as<common_comparison_category_t<_Cat>, _Cat>);
1692 
1693  if (!std::is_constant_evaluated())
1694  if constexpr (same_as<_Comp, __detail::_Synth3way>
1695  || same_as<_Comp, compare_three_way>)
1696  if constexpr (__is_byte_iter<_InputIter1>)
1697  if constexpr (__is_byte_iter<_InputIter2>)
1698  {
1699  const auto [__len, __lencmp]
1700  = std::__min_cmp(__last1 - __first1, __last2 - __first2);
1701  if (__len)
1702  {
1703  const auto __c
1704  = __builtin_memcmp(&*__first1, &*__first2, __len) <=> 0;
1705  if (__c != 0)
1706  return __c;
1707  }
1708  return __lencmp;
1709  }
1710 #endif // is_constant_evaluated
1711  while (__first1 != __last1 && __first2 != __last2)
1712  {
1713  if (auto __cmp = __comp(*__first1, *__first2); __cmp != 0)
1714  return __cmp;
1715  ++__first1;
1716  ++__first2;
1717  }
1718  return __first1 != __last1 ? strong_ordering::greater
1719  : __first2 != __last2 ? strong_ordering::less : strong_ordering::equal;
1720  }
1721 
1722  template<typename _InputIter1, typename _InputIter2>
1723  constexpr auto
1724  lexicographical_compare_three_way(_InputIter1 __first1,
1725  _InputIter1 __last1,
1726  _InputIter2 __first2,
1727  _InputIter2 __last2)
1728  {
1729  return std::lexicographical_compare_three_way(__first1, __last1,
1730  __first2, __last2,
1731  compare_three_way{});
1732  }
1733 #endif // three_way_comparison
1734 
1735  template<typename _InputIterator1, typename _InputIterator2,
1736  typename _BinaryPredicate>
1737  _GLIBCXX20_CONSTEXPR
1738  pair<_InputIterator1, _InputIterator2>
1739  __mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1740  _InputIterator2 __first2, _BinaryPredicate __binary_pred)
1741  {
1742  while (__first1 != __last1 && __binary_pred(__first1, __first2))
1743  {
1744  ++__first1;
1745  ++__first2;
1746  }
1747  return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
1748  }
1749 
1750  /**
1751  * @brief Finds the places in ranges which don't match.
1752  * @ingroup non_mutating_algorithms
1753  * @param __first1 An input iterator.
1754  * @param __last1 An input iterator.
1755  * @param __first2 An input iterator.
1756  * @return A pair of iterators pointing to the first mismatch.
1757  *
1758  * This compares the elements of two ranges using @c == and returns a pair
1759  * of iterators. The first iterator points into the first range, the
1760  * second iterator points into the second range, and the elements pointed
1761  * to by the iterators are not equal.
1762  */
1763  template<typename _InputIterator1, typename _InputIterator2>
1764  _GLIBCXX20_CONSTEXPR
1765  inline pair<_InputIterator1, _InputIterator2>
1766  mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1767  _InputIterator2 __first2)
1768  {
1769  // concept requirements
1770  __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
1771  __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
1772  __glibcxx_function_requires(_EqualOpConcept<
1775  __glibcxx_requires_valid_range(__first1, __last1);
1776 
1777  return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2,
1778  __gnu_cxx::__ops::__iter_equal_to_iter());
1779  }
1780 
1781  /**
1782  * @brief Finds the places in ranges which don't match.
1783  * @ingroup non_mutating_algorithms
1784  * @param __first1 An input iterator.
1785  * @param __last1 An input iterator.
1786  * @param __first2 An input iterator.
1787  * @param __binary_pred A binary predicate @link functors
1788  * functor@endlink.
1789  * @return A pair of iterators pointing to the first mismatch.
1790  *
1791  * This compares the elements of two ranges using the binary_pred
1792  * parameter, and returns a pair
1793  * of iterators. The first iterator points into the first range, the
1794  * second iterator points into the second range, and the elements pointed
1795  * to by the iterators are not equal.
1796  */
1797  template<typename _InputIterator1, typename _InputIterator2,
1798  typename _BinaryPredicate>
1799  _GLIBCXX20_CONSTEXPR
1800  inline pair<_InputIterator1, _InputIterator2>
1801  mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1802  _InputIterator2 __first2, _BinaryPredicate __binary_pred)
1803  {
1804  // concept requirements
1805  __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
1806  __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
1807  __glibcxx_requires_valid_range(__first1, __last1);
1808 
1809  return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2,
1810  __gnu_cxx::__ops::__iter_comp_iter(__binary_pred));
1811  }
1812 
1813 #if __cplusplus > 201103L
1814 
1815  template<typename _InputIterator1, typename _InputIterator2,
1816  typename _BinaryPredicate>
1817  _GLIBCXX20_CONSTEXPR
1818  pair<_InputIterator1, _InputIterator2>
1819  __mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1820  _InputIterator2 __first2, _InputIterator2 __last2,
1821  _BinaryPredicate __binary_pred)
1822  {
1823  while (__first1 != __last1 && __first2 != __last2
1824  && __binary_pred(__first1, __first2))
1825  {
1826  ++__first1;
1827  ++__first2;
1828  }
1829  return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
1830  }
1831 
1832  /**
1833  * @brief Finds the places in ranges which don't match.
1834  * @ingroup non_mutating_algorithms
1835  * @param __first1 An input iterator.
1836  * @param __last1 An input iterator.
1837  * @param __first2 An input iterator.
1838  * @param __last2 An input iterator.
1839  * @return A pair of iterators pointing to the first mismatch.
1840  *
1841  * This compares the elements of two ranges using @c == and returns a pair
1842  * of iterators. The first iterator points into the first range, the
1843  * second iterator points into the second range, and the elements pointed
1844  * to by the iterators are not equal.
1845  */
1846  template<typename _InputIterator1, typename _InputIterator2>
1847  _GLIBCXX20_CONSTEXPR
1848  inline pair<_InputIterator1, _InputIterator2>
1849  mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1850  _InputIterator2 __first2, _InputIterator2 __last2)
1851  {
1852  // concept requirements
1853  __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
1854  __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
1855  __glibcxx_function_requires(_EqualOpConcept<
1858  __glibcxx_requires_valid_range(__first1, __last1);
1859  __glibcxx_requires_valid_range(__first2, __last2);
1860 
1861  return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2, __last2,
1862  __gnu_cxx::__ops::__iter_equal_to_iter());
1863  }
1864 
1865  /**
1866  * @brief Finds the places in ranges which don't match.
1867  * @ingroup non_mutating_algorithms
1868  * @param __first1 An input iterator.
1869  * @param __last1 An input iterator.
1870  * @param __first2 An input iterator.
1871  * @param __last2 An input iterator.
1872  * @param __binary_pred A binary predicate @link functors
1873  * functor@endlink.
1874  * @return A pair of iterators pointing to the first mismatch.
1875  *
1876  * This compares the elements of two ranges using the binary_pred
1877  * parameter, and returns a pair
1878  * of iterators. The first iterator points into the first range, the
1879  * second iterator points into the second range, and the elements pointed
1880  * to by the iterators are not equal.
1881  */
1882  template<typename _InputIterator1, typename _InputIterator2,
1883  typename _BinaryPredicate>
1884  _GLIBCXX20_CONSTEXPR
1885  inline pair<_InputIterator1, _InputIterator2>
1886  mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1887  _InputIterator2 __first2, _InputIterator2 __last2,
1888  _BinaryPredicate __binary_pred)
1889  {
1890  // concept requirements
1891  __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
1892  __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
1893  __glibcxx_requires_valid_range(__first1, __last1);
1894  __glibcxx_requires_valid_range(__first2, __last2);
1895 
1896  return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2, __last2,
1897  __gnu_cxx::__ops::__iter_comp_iter(__binary_pred));
1898  }
1899 #endif
1900 
1901 _GLIBCXX_END_NAMESPACE_ALGO
1902 _GLIBCXX_END_NAMESPACE_VERSION
1903 } // namespace std
1904 
1905 // NB: This file is included within many other C++ includes, as a way
1906 // of getting the base algorithms. So, make sure that parallel bits
1907 // come in too if requested.
1908 #ifdef _GLIBCXX_PARALLEL
1909 # include <parallel/algobase.h>
1910 #endif
1911 
1912 #endif
std::iter_swap
constexpr void iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
Swaps the contents of two iterators.
Definition: stl_algobase.h:149
std::output_iterator_tag
Marking output iterators.
Definition: stl_iterator_base_types.h:96
std::equal
constexpr bool equal(_IIter1 __first1, _IIter1 __last1, _IIter2 __first2, _IIter2 __last2, _BinaryPredicate __binary_pred)
Tests a range for element-wise equality.
Definition: stl_algobase.h:1556
std::__iterator_category
constexpr iterator_traits< _Iter >::iterator_category __iterator_category(const _Iter &)
Definition: stl_iterator_base_types.h:238
std::distance
constexpr iterator_traits< _InputIterator >::difference_type distance(_InputIterator __first, _InputIterator __last)
A generalization of pointer arithmetic.
Definition: stl_iterator_base_funcs.h:138
type_traits.h
std::min
constexpr const _Tp & min(const _Tp &, const _Tp &)
This does what you think it does.
Definition: stl_algobase.h:227
std::move_backward
constexpr _BI2 move_backward(_BI1 __first, _BI1 __last, _BI2 __result)
Moves the range [first,last) into result.
Definition: stl_algobase.h:842
stl_iterator.h
functexcept.h
stl_iterator_base_funcs.h
std
ISO C++ entities toplevel namespace is std.
algobase.h
Parallel STL function calls corresponding to the stl_algobase.h header. The functions defined here ma...
std::_Deque_iterator
A deque::iterator.
Definition: stl_algobase.h:481
std::__lg
constexpr int __lg(int __n)
This is a helper function for the sort routines and for random.tcc.
Definition: stl_algobase.h:1362
std::random_access_iterator_tag
Random-access iterators support a superset of bidirectional iterator operations.
Definition: stl_iterator_base_types.h:107
c++config.h
stl_pair.h
std::advance
constexpr void advance(_InputIterator &__i, _Distance __n)
A generalization of pointer arithmetic.
Definition: stl_iterator_base_funcs.h:202
std::max
constexpr const _Tp & max(const _Tp &, const _Tp &)
This does what you think it does.
Definition: stl_algobase.h:251
std::copy
constexpr _OI copy(_II __first, _II __last, _OI __result)
Copies the range [first,last) into result.
Definition: stl_algobase.h:563
move.h
__gnu_debug::_Safe_iterator
Safe iterator wrapper.
Definition: debug.h:61
cpp_type_traits.h
std::input_iterator_tag
Marking input iterators.
Definition: stl_iterator_base_types.h:93
predefined_ops.h
std::is_nothrow_copy_constructible
is_nothrow_copy_constructible
Definition: type_traits:1043
numeric_traits.h
type_traits
stl_iterator_base_types.h
debug.h
compare
std::iterator_traits
Traits class for iterators.
Definition: stl_iterator_base_types.h:150
concept_check.h
std::move
constexpr std::remove_reference< _Tp >::type && move(_Tp &&__t) noexcept
Convert a value to an rvalue.
Definition: move.h:101