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
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10 
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15 
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18 // 3.1, as published by the Free Software Foundation.
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24 
25 /*
26  *
27  * Copyright (c) 1994
28  * Hewlett-Packard Company
29  *
30  * Permission to use, copy, modify, distribute and sell this software
31  * and its documentation for any purpose is hereby granted without fee,
32  * provided that the above copyright notice appear in all copies and
33  * that both that copyright notice and this permission notice appear
34  * in supporting documentation. Hewlett-Packard Company makes no
35  * representations about the suitability of this software for any
36  * purpose. It is provided "as is" without express or implied warranty.
37  *
38  *
39  * Copyright (c) 1996-1998
40  * Silicon Graphics Computer Systems, Inc.
41  *
42  * Permission to use, copy, modify, distribute and sell this software
43  * and its documentation for any purpose is hereby granted without fee,
44  * provided that the above copyright notice appear in all copies and
45  * that both that copyright notice and this permission notice appear
46  * in supporting documentation. Silicon Graphics makes no
47  * representations about the suitability of this software for any
48  * purpose. It is provided "as is" without express or implied warranty.
49  */
50 
51 /** @file bits/stl_algobase.h
52  * This is an internal header file, included by other library headers.
53  * Do not attempt to use it directly. @headername{algorithm}
54  */
55 
56 #ifndef _STL_ALGOBASE_H
57 #define _STL_ALGOBASE_H 1
58 
59 #include <bits/c++config.h>
60 #include <bits/functexcept.h>
61 #include <bits/cpp_type_traits.h>
62 #include <ext/type_traits.h>
63 #include <ext/numeric_traits.h>
64 #include <bits/stl_pair.h>
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 
83 namespace 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
100  if (std::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
156  iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
157  {
158  // concept requirements
159  __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
160  _ForwardIterator1>)
161  __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
162  _ForwardIterator2>)
163 
164 #if __cplusplus < 201103L
166  _ValueType1;
168  _ValueType2;
169 
170  __glibcxx_function_requires(_ConvertibleConcept<_ValueType1,
171  _ValueType2>)
172  __glibcxx_function_requires(_ConvertibleConcept<_ValueType2,
173  _ValueType1>)
174 
176  _ReferenceType1;
178  _ReferenceType2;
179  std::__iter_swap<__are_same<_ValueType1, _ValueType2>::__value
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
205  swap_ranges(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
206  _ForwardIterator2 __first2)
207  {
208  // concept requirements
209  __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
210  _ForwardIterator1>)
211  __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
212  _ForwardIterator2>)
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
543  else if (std::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 
641  return std::__copy_move_a<__is_move_iterator<_II>::__value>
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
695  else if (std::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,
784  std::__copy_move_backward_a1<_IsMove>
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 
846  return std::__copy_move_backward_a<__is_move_iterator<_BI1>::__value>
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
943  if (std::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<
1008  _ForwardIterator>)
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)
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
1587  equal(_II1 __first1, _II1 __last1, _II2 __first2)
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
1618  equal(_IIter1 __first1, _IIter1 __last1,
1619  _IIter2 __first2, _BinaryPredicate __binary_pred)
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
1709  equal(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
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
1742  equal(_IIter1 __first1, _IIter1 __last1,
1743  _IIter2 __first2, _IIter2 __last2, _BinaryPredicate __binary_pred)
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,
1752  __binary_pred);
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,
1775  _II2 __first2, _II2 __last2)
1776  {
1777 #ifdef _GLIBCXX_CONCEPT_CHECKS
1778  // concept requirements
1779  typedef typename iterator_traits<_II1>::value_type _ValueType1;
1780  typedef typename iterator_traits<_II2>::value_type _ValueType2;
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
1819  (__first1, __last1, __first2, __last2,
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
1863  _InputIter1 __last1,
1864  _InputIter2 __first2,
1865  _InputIter2 __last2,
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));
1876  static_assert(same_as<common_comparison_category_t<_Cat>, _Cat>);
1877 
1878  if (!std::__is_constant_evaluated())
1879  if constexpr (same_as<_Comp, __detail::_Synth3way>
1880  || same_as<_Comp, compare_three_way>)
1881  if constexpr (__memcmp_ordered_with<_InputIter1, _InputIter2>)
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
1889  = __builtin_memcmp(&*__first1, &*__first2, __blen) <=> 0;
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>
1952  mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1953  _InputIterator2 __first2)
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>
1987  mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1988  _InputIterator2 __first2, _BinaryPredicate __binary_pred)
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>
2034  mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
2035  _InputIterator2 __first2, _InputIterator2 __last2)
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>
2071  mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
2072  _InputIterator2 __first2, _InputIterator2 __last2,
2073  _BinaryPredicate __binary_pred)
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
2233  is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
2234  _ForwardIterator2 __first2)
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
2276  search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
2277  _ForwardIterator2 __first2, _ForwardIterator2 __last2,
2278  _BinaryPredicate __predicate)
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
typename make_unsigned< _Tp >::type make_unsigned_t
Alias template for make_unsigned.
Definition: type_traits:2143
constexpr std::remove_reference< _Tp >::type && move(_Tp &&__t) noexcept
Convert a value to an rvalue.
Definition: move.h:138
constexpr void fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp &__value)
Fills the range [first,last) with copies of value.
constexpr _OI copy(_II __first, _II __last, _OI __result)
Copies the range [first,last) into result.
Definition: stl_algobase.h:633
constexpr _BI2 copy_backward(_BI1 __first, _BI1 __last, _BI2 __result)
Copies the range [first,last) into result.
Definition: stl_algobase.h:837
constexpr _BI2 move_backward(_BI1 __first, _BI1 __last, _BI2 __result)
Moves the range [first,last) into result.
Definition: stl_algobase.h:873
constexpr _OI fill_n(_OI __first, _Size __n, const _Tp &__value)
Fills the range [first,first+n) with copies of value.
constexpr bool equal(_IIter1 __first1, _IIter1 __last1, _IIter2 __first2, _IIter2 __last2, _BinaryPredicate __binary_pred)
Tests a range for element-wise equality.
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.
Definition: stl_algobase.h:258
constexpr const _Tp & min(const _Tp &, const _Tp &)
This does what you think it does.
Definition: stl_algobase.h:234
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.