libstdc++
stl_algobase.h
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1 // Core algorithmic facilities -*- C++ -*-
2 
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25 /*
26  *
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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 and _GLIBCXX_MOVE
71 #include <bits/predefined_ops.h>
72 
73 namespace std _GLIBCXX_VISIBILITY(default)
74 {
75 _GLIBCXX_BEGIN_NAMESPACE_VERSION
76 
77 #if __cplusplus < 201103L
78  // See http://gcc.gnu.org/ml/libstdc++/2004-08/msg00167.html: in a
79  // nutshell, we are partially implementing the resolution of DR 187,
80  // when it's safe, i.e., the value_types are equal.
81  template<bool _BoolType>
82  struct __iter_swap
83  {
84  template<typename _ForwardIterator1, typename _ForwardIterator2>
85  static void
86  iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
87  {
88  typedef typename iterator_traits<_ForwardIterator1>::value_type
89  _ValueType1;
90  _ValueType1 __tmp = _GLIBCXX_MOVE(*__a);
91  *__a = _GLIBCXX_MOVE(*__b);
92  *__b = _GLIBCXX_MOVE(__tmp);
93  }
94  };
95 
96  template<>
97  struct __iter_swap<true>
98  {
99  template<typename _ForwardIterator1, typename _ForwardIterator2>
100  static void
101  iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
102  {
103  swap(*__a, *__b);
104  }
105  };
106 #endif
107 
108  /**
109  * @brief Swaps the contents of two iterators.
110  * @ingroup mutating_algorithms
111  * @param __a An iterator.
112  * @param __b Another iterator.
113  * @return Nothing.
114  *
115  * This function swaps the values pointed to by two iterators, not the
116  * iterators themselves.
117  */
118  template<typename _ForwardIterator1, typename _ForwardIterator2>
119  inline void
120  iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
121  {
122  // concept requirements
123  __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
124  _ForwardIterator1>)
125  __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
126  _ForwardIterator2>)
127 
128 #if __cplusplus < 201103L
129  typedef typename iterator_traits<_ForwardIterator1>::value_type
130  _ValueType1;
131  typedef typename iterator_traits<_ForwardIterator2>::value_type
132  _ValueType2;
133 
134  __glibcxx_function_requires(_ConvertibleConcept<_ValueType1,
135  _ValueType2>)
136  __glibcxx_function_requires(_ConvertibleConcept<_ValueType2,
137  _ValueType1>)
138 
139  typedef typename iterator_traits<_ForwardIterator1>::reference
140  _ReferenceType1;
141  typedef typename iterator_traits<_ForwardIterator2>::reference
142  _ReferenceType2;
143  std::__iter_swap<__are_same<_ValueType1, _ValueType2>::__value
144  && __are_same<_ValueType1&, _ReferenceType1>::__value
145  && __are_same<_ValueType2&, _ReferenceType2>::__value>::
146  iter_swap(__a, __b);
147 #else
148  swap(*__a, *__b);
149 #endif
150  }
151 
152  /**
153  * @brief Swap the elements of two sequences.
154  * @ingroup mutating_algorithms
155  * @param __first1 A forward iterator.
156  * @param __last1 A forward iterator.
157  * @param __first2 A forward iterator.
158  * @return An iterator equal to @p first2+(last1-first1).
159  *
160  * Swaps each element in the range @p [first1,last1) with the
161  * corresponding element in the range @p [first2,(last1-first1)).
162  * The ranges must not overlap.
163  */
164  template<typename _ForwardIterator1, typename _ForwardIterator2>
165  _ForwardIterator2
166  swap_ranges(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
167  _ForwardIterator2 __first2)
168  {
169  // concept requirements
170  __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
171  _ForwardIterator1>)
172  __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
173  _ForwardIterator2>)
174  __glibcxx_requires_valid_range(__first1, __last1);
175 
176  for (; __first1 != __last1; ++__first1, (void)++__first2)
177  std::iter_swap(__first1, __first2);
178  return __first2;
179  }
180 
181  /**
182  * @brief This does what you think it does.
183  * @ingroup sorting_algorithms
184  * @param __a A thing of arbitrary type.
185  * @param __b Another thing of arbitrary type.
186  * @return The lesser of the parameters.
187  *
188  * This is the simple classic generic implementation. It will work on
189  * temporary expressions, since they are only evaluated once, unlike a
190  * preprocessor macro.
191  */
192  template<typename _Tp>
193  _GLIBCXX14_CONSTEXPR
194  inline const _Tp&
195  min(const _Tp& __a, const _Tp& __b)
196  {
197  // concept requirements
198  __glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
199  //return __b < __a ? __b : __a;
200  if (__b < __a)
201  return __b;
202  return __a;
203  }
204 
205  /**
206  * @brief This does what you think it does.
207  * @ingroup sorting_algorithms
208  * @param __a A thing of arbitrary type.
209  * @param __b Another thing of arbitrary type.
210  * @return The greater of the parameters.
211  *
212  * This is the simple classic generic implementation. It will work on
213  * temporary expressions, since they are only evaluated once, unlike a
214  * preprocessor macro.
215  */
216  template<typename _Tp>
217  _GLIBCXX14_CONSTEXPR
218  inline const _Tp&
219  max(const _Tp& __a, const _Tp& __b)
220  {
221  // concept requirements
222  __glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
223  //return __a < __b ? __b : __a;
224  if (__a < __b)
225  return __b;
226  return __a;
227  }
228 
229  /**
230  * @brief This does what you think it does.
231  * @ingroup sorting_algorithms
232  * @param __a A thing of arbitrary type.
233  * @param __b Another thing of arbitrary type.
234  * @param __comp A @link comparison_functors comparison functor@endlink.
235  * @return The lesser of the parameters.
236  *
237  * This will work on temporary expressions, since they are only evaluated
238  * once, unlike a preprocessor macro.
239  */
240  template<typename _Tp, typename _Compare>
241  _GLIBCXX14_CONSTEXPR
242  inline const _Tp&
243  min(const _Tp& __a, const _Tp& __b, _Compare __comp)
244  {
245  //return __comp(__b, __a) ? __b : __a;
246  if (__comp(__b, __a))
247  return __b;
248  return __a;
249  }
250 
251  /**
252  * @brief This does what you think it does.
253  * @ingroup sorting_algorithms
254  * @param __a A thing of arbitrary type.
255  * @param __b Another thing of arbitrary type.
256  * @param __comp A @link comparison_functors comparison functor@endlink.
257  * @return The greater of the parameters.
258  *
259  * This will work on temporary expressions, since they are only evaluated
260  * once, unlike a preprocessor macro.
261  */
262  template<typename _Tp, typename _Compare>
263  _GLIBCXX14_CONSTEXPR
264  inline const _Tp&
265  max(const _Tp& __a, const _Tp& __b, _Compare __comp)
266  {
267  //return __comp(__a, __b) ? __b : __a;
268  if (__comp(__a, __b))
269  return __b;
270  return __a;
271  }
272 
273  // Fallback implementation of the function in bits/stl_iterator.h used to
274  // remove the __normal_iterator wrapper. See copy, fill, ...
275  template<typename _Iterator>
276  inline _Iterator
277  __niter_base(_Iterator __it)
278  { return __it; }
279 
280  // All of these auxiliary structs serve two purposes. (1) Replace
281  // calls to copy with memmove whenever possible. (Memmove, not memcpy,
282  // because the input and output ranges are permitted to overlap.)
283  // (2) If we're using random access iterators, then write the loop as
284  // a for loop with an explicit count.
285 
286  template<bool, bool, typename>
287  struct __copy_move
288  {
289  template<typename _II, typename _OI>
290  static _OI
291  __copy_m(_II __first, _II __last, _OI __result)
292  {
293  for (; __first != __last; ++__result, (void)++__first)
294  *__result = *__first;
295  return __result;
296  }
297  };
298 
299 #if __cplusplus >= 201103L
300  template<typename _Category>
301  struct __copy_move<true, false, _Category>
302  {
303  template<typename _II, typename _OI>
304  static _OI
305  __copy_m(_II __first, _II __last, _OI __result)
306  {
307  for (; __first != __last; ++__result, (void)++__first)
308  *__result = std::move(*__first);
309  return __result;
310  }
311  };
312 #endif
313 
314  template<>
315  struct __copy_move<false, false, random_access_iterator_tag>
316  {
317  template<typename _II, typename _OI>
318  static _OI
319  __copy_m(_II __first, _II __last, _OI __result)
320  {
321  typedef typename iterator_traits<_II>::difference_type _Distance;
322  for(_Distance __n = __last - __first; __n > 0; --__n)
323  {
324  *__result = *__first;
325  ++__first;
326  ++__result;
327  }
328  return __result;
329  }
330  };
331 
332 #if __cplusplus >= 201103L
333  template<>
334  struct __copy_move<true, false, random_access_iterator_tag>
335  {
336  template<typename _II, typename _OI>
337  static _OI
338  __copy_m(_II __first, _II __last, _OI __result)
339  {
340  typedef typename iterator_traits<_II>::difference_type _Distance;
341  for(_Distance __n = __last - __first; __n > 0; --__n)
342  {
343  *__result = std::move(*__first);
344  ++__first;
345  ++__result;
346  }
347  return __result;
348  }
349  };
350 #endif
351 
352  template<bool _IsMove>
353  struct __copy_move<_IsMove, true, random_access_iterator_tag>
354  {
355  template<typename _Tp>
356  static _Tp*
357  __copy_m(const _Tp* __first, const _Tp* __last, _Tp* __result)
358  {
359 #if __cplusplus >= 201103L
360  using __assignable = conditional<_IsMove,
361  is_move_assignable<_Tp>,
362  is_copy_assignable<_Tp>>;
363  // trivial types can have deleted assignment
364  static_assert( __assignable::type::value, "type is not assignable" );
365 #endif
366  const ptrdiff_t _Num = __last - __first;
367  if (_Num)
368  __builtin_memmove(__result, __first, sizeof(_Tp) * _Num);
369  return __result + _Num;
370  }
371  };
372 
373  template<bool _IsMove, typename _II, typename _OI>
374  inline _OI
375  __copy_move_a(_II __first, _II __last, _OI __result)
376  {
377  typedef typename iterator_traits<_II>::value_type _ValueTypeI;
378  typedef typename iterator_traits<_OI>::value_type _ValueTypeO;
379  typedef typename iterator_traits<_II>::iterator_category _Category;
380  const bool __simple = (__is_trivial(_ValueTypeI)
381  && __is_pointer<_II>::__value
382  && __is_pointer<_OI>::__value
383  && __are_same<_ValueTypeI, _ValueTypeO>::__value);
384 
385  return std::__copy_move<_IsMove, __simple,
386  _Category>::__copy_m(__first, __last, __result);
387  }
388 
389  // Helpers for streambuf iterators (either istream or ostream).
390  // NB: avoid including <iosfwd>, relatively large.
391  template<typename _CharT>
392  struct char_traits;
393 
394  template<typename _CharT, typename _Traits>
395  class istreambuf_iterator;
396 
397  template<typename _CharT, typename _Traits>
398  class ostreambuf_iterator;
399 
400  template<bool _IsMove, typename _CharT>
401  typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
403  __copy_move_a2(_CharT*, _CharT*,
405 
406  template<bool _IsMove, typename _CharT>
407  typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
409  __copy_move_a2(const _CharT*, const _CharT*,
411 
412  template<bool _IsMove, typename _CharT>
413  typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
414  _CharT*>::__type
415  __copy_move_a2(istreambuf_iterator<_CharT, char_traits<_CharT> >,
416  istreambuf_iterator<_CharT, char_traits<_CharT> >, _CharT*);
417 
418  template<bool _IsMove, typename _II, typename _OI>
419  inline _OI
420  __copy_move_a2(_II __first, _II __last, _OI __result)
421  {
422  return _OI(std::__copy_move_a<_IsMove>(std::__niter_base(__first),
423  std::__niter_base(__last),
424  std::__niter_base(__result)));
425  }
426 
427  /**
428  * @brief Copies the range [first,last) into result.
429  * @ingroup mutating_algorithms
430  * @param __first An input iterator.
431  * @param __last An input iterator.
432  * @param __result An output iterator.
433  * @return result + (first - last)
434  *
435  * This inline function will boil down to a call to @c memmove whenever
436  * possible. Failing that, if random access iterators are passed, then the
437  * loop count will be known (and therefore a candidate for compiler
438  * optimizations such as unrolling). Result may not be contained within
439  * [first,last); the copy_backward function should be used instead.
440  *
441  * Note that the end of the output range is permitted to be contained
442  * within [first,last).
443  */
444  template<typename _II, typename _OI>
445  inline _OI
446  copy(_II __first, _II __last, _OI __result)
447  {
448  // concept requirements
449  __glibcxx_function_requires(_InputIteratorConcept<_II>)
450  __glibcxx_function_requires(_OutputIteratorConcept<_OI,
451  typename iterator_traits<_II>::value_type>)
452  __glibcxx_requires_valid_range(__first, __last);
453 
454  return (std::__copy_move_a2<__is_move_iterator<_II>::__value>
455  (std::__miter_base(__first), std::__miter_base(__last),
456  __result));
457  }
458 
459 #if __cplusplus >= 201103L
460  /**
461  * @brief Moves the range [first,last) into result.
462  * @ingroup mutating_algorithms
463  * @param __first An input iterator.
464  * @param __last An input iterator.
465  * @param __result An output iterator.
466  * @return result + (first - last)
467  *
468  * This inline function will boil down to a call to @c memmove whenever
469  * possible. Failing that, if random access iterators are passed, then the
470  * loop count will be known (and therefore a candidate for compiler
471  * optimizations such as unrolling). Result may not be contained within
472  * [first,last); the move_backward function should be used instead.
473  *
474  * Note that the end of the output range is permitted to be contained
475  * within [first,last).
476  */
477  template<typename _II, typename _OI>
478  inline _OI
479  move(_II __first, _II __last, _OI __result)
480  {
481  // concept requirements
482  __glibcxx_function_requires(_InputIteratorConcept<_II>)
483  __glibcxx_function_requires(_OutputIteratorConcept<_OI,
484  typename iterator_traits<_II>::value_type>)
485  __glibcxx_requires_valid_range(__first, __last);
486 
487  return std::__copy_move_a2<true>(std::__miter_base(__first),
488  std::__miter_base(__last), __result);
489  }
490 
491 #define _GLIBCXX_MOVE3(_Tp, _Up, _Vp) std::move(_Tp, _Up, _Vp)
492 #else
493 #define _GLIBCXX_MOVE3(_Tp, _Up, _Vp) std::copy(_Tp, _Up, _Vp)
494 #endif
495 
496  template<bool, bool, typename>
497  struct __copy_move_backward
498  {
499  template<typename _BI1, typename _BI2>
500  static _BI2
501  __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
502  {
503  while (__first != __last)
504  *--__result = *--__last;
505  return __result;
506  }
507  };
508 
509 #if __cplusplus >= 201103L
510  template<typename _Category>
511  struct __copy_move_backward<true, false, _Category>
512  {
513  template<typename _BI1, typename _BI2>
514  static _BI2
515  __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
516  {
517  while (__first != __last)
518  *--__result = std::move(*--__last);
519  return __result;
520  }
521  };
522 #endif
523 
524  template<>
525  struct __copy_move_backward<false, false, random_access_iterator_tag>
526  {
527  template<typename _BI1, typename _BI2>
528  static _BI2
529  __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
530  {
531  typename iterator_traits<_BI1>::difference_type __n;
532  for (__n = __last - __first; __n > 0; --__n)
533  *--__result = *--__last;
534  return __result;
535  }
536  };
537 
538 #if __cplusplus >= 201103L
539  template<>
540  struct __copy_move_backward<true, false, random_access_iterator_tag>
541  {
542  template<typename _BI1, typename _BI2>
543  static _BI2
544  __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
545  {
546  typename iterator_traits<_BI1>::difference_type __n;
547  for (__n = __last - __first; __n > 0; --__n)
548  *--__result = std::move(*--__last);
549  return __result;
550  }
551  };
552 #endif
553 
554  template<bool _IsMove>
555  struct __copy_move_backward<_IsMove, true, random_access_iterator_tag>
556  {
557  template<typename _Tp>
558  static _Tp*
559  __copy_move_b(const _Tp* __first, const _Tp* __last, _Tp* __result)
560  {
561 #if __cplusplus >= 201103L
562  using __assignable = conditional<_IsMove,
563  is_move_assignable<_Tp>,
564  is_copy_assignable<_Tp>>;
565  // trivial types can have deleted assignment
566  static_assert( __assignable::type::value, "type is not assignable" );
567 #endif
568  const ptrdiff_t _Num = __last - __first;
569  if (_Num)
570  __builtin_memmove(__result - _Num, __first, sizeof(_Tp) * _Num);
571  return __result - _Num;
572  }
573  };
574 
575  template<bool _IsMove, typename _BI1, typename _BI2>
576  inline _BI2
577  __copy_move_backward_a(_BI1 __first, _BI1 __last, _BI2 __result)
578  {
579  typedef typename iterator_traits<_BI1>::value_type _ValueType1;
580  typedef typename iterator_traits<_BI2>::value_type _ValueType2;
581  typedef typename iterator_traits<_BI1>::iterator_category _Category;
582  const bool __simple = (__is_trivial(_ValueType1)
583  && __is_pointer<_BI1>::__value
584  && __is_pointer<_BI2>::__value
585  && __are_same<_ValueType1, _ValueType2>::__value);
586 
587  return std::__copy_move_backward<_IsMove, __simple,
588  _Category>::__copy_move_b(__first,
589  __last,
590  __result);
591  }
592 
593  template<bool _IsMove, typename _BI1, typename _BI2>
594  inline _BI2
595  __copy_move_backward_a2(_BI1 __first, _BI1 __last, _BI2 __result)
596  {
597  return _BI2(std::__copy_move_backward_a<_IsMove>
598  (std::__niter_base(__first), std::__niter_base(__last),
599  std::__niter_base(__result)));
600  }
601 
602  /**
603  * @brief Copies the range [first,last) into result.
604  * @ingroup mutating_algorithms
605  * @param __first A bidirectional iterator.
606  * @param __last A bidirectional iterator.
607  * @param __result A bidirectional iterator.
608  * @return result - (first - last)
609  *
610  * The function has the same effect as copy, but starts at the end of the
611  * range and works its way to the start, returning the start of the result.
612  * This inline function will boil down to a call to @c memmove whenever
613  * possible. Failing that, if random access iterators are passed, then the
614  * loop count will be known (and therefore a candidate for compiler
615  * optimizations such as unrolling).
616  *
617  * Result may not be in the range (first,last]. Use copy instead. Note
618  * that the start of the output range may overlap [first,last).
619  */
620  template<typename _BI1, typename _BI2>
621  inline _BI2
622  copy_backward(_BI1 __first, _BI1 __last, _BI2 __result)
623  {
624  // concept requirements
625  __glibcxx_function_requires(_BidirectionalIteratorConcept<_BI1>)
626  __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<_BI2>)
627  __glibcxx_function_requires(_ConvertibleConcept<
628  typename iterator_traits<_BI1>::value_type,
629  typename iterator_traits<_BI2>::value_type>)
630  __glibcxx_requires_valid_range(__first, __last);
631 
632  return (std::__copy_move_backward_a2<__is_move_iterator<_BI1>::__value>
633  (std::__miter_base(__first), std::__miter_base(__last),
634  __result));
635  }
636 
637 #if __cplusplus >= 201103L
638  /**
639  * @brief Moves the range [first,last) into result.
640  * @ingroup mutating_algorithms
641  * @param __first A bidirectional iterator.
642  * @param __last A bidirectional iterator.
643  * @param __result A bidirectional iterator.
644  * @return result - (first - last)
645  *
646  * The function has the same effect as move, but starts at the end of the
647  * range and works its way to the start, returning the start of the result.
648  * This inline function will boil down to a call to @c memmove whenever
649  * possible. Failing that, if random access iterators are passed, then the
650  * loop count will be known (and therefore a candidate for compiler
651  * optimizations such as unrolling).
652  *
653  * Result may not be in the range (first,last]. Use move instead. Note
654  * that the start of the output range may overlap [first,last).
655  */
656  template<typename _BI1, typename _BI2>
657  inline _BI2
658  move_backward(_BI1 __first, _BI1 __last, _BI2 __result)
659  {
660  // concept requirements
661  __glibcxx_function_requires(_BidirectionalIteratorConcept<_BI1>)
662  __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<_BI2>)
663  __glibcxx_function_requires(_ConvertibleConcept<
664  typename iterator_traits<_BI1>::value_type,
665  typename iterator_traits<_BI2>::value_type>)
666  __glibcxx_requires_valid_range(__first, __last);
667 
668  return std::__copy_move_backward_a2<true>(std::__miter_base(__first),
669  std::__miter_base(__last),
670  __result);
671  }
672 
673 #define _GLIBCXX_MOVE_BACKWARD3(_Tp, _Up, _Vp) std::move_backward(_Tp, _Up, _Vp)
674 #else
675 #define _GLIBCXX_MOVE_BACKWARD3(_Tp, _Up, _Vp) std::copy_backward(_Tp, _Up, _Vp)
676 #endif
677 
678  template<typename _ForwardIterator, typename _Tp>
679  inline typename
680  __gnu_cxx::__enable_if<!__is_scalar<_Tp>::__value, void>::__type
681  __fill_a(_ForwardIterator __first, _ForwardIterator __last,
682  const _Tp& __value)
683  {
684  for (; __first != __last; ++__first)
685  *__first = __value;
686  }
687 
688  template<typename _ForwardIterator, typename _Tp>
689  inline typename
690  __gnu_cxx::__enable_if<__is_scalar<_Tp>::__value, void>::__type
691  __fill_a(_ForwardIterator __first, _ForwardIterator __last,
692  const _Tp& __value)
693  {
694  const _Tp __tmp = __value;
695  for (; __first != __last; ++__first)
696  *__first = __tmp;
697  }
698 
699  // Specialization: for char types we can use memset.
700  template<typename _Tp>
701  inline typename
702  __gnu_cxx::__enable_if<__is_byte<_Tp>::__value, void>::__type
703  __fill_a(_Tp* __first, _Tp* __last, const _Tp& __c)
704  {
705  const _Tp __tmp = __c;
706  if (const size_t __len = __last - __first)
707  __builtin_memset(__first, static_cast<unsigned char>(__tmp), __len);
708  }
709 
710  /**
711  * @brief Fills the range [first,last) with copies of value.
712  * @ingroup mutating_algorithms
713  * @param __first A forward iterator.
714  * @param __last A forward iterator.
715  * @param __value A reference-to-const of arbitrary type.
716  * @return Nothing.
717  *
718  * This function fills a range with copies of the same value. For char
719  * types filling contiguous areas of memory, this becomes an inline call
720  * to @c memset or @c wmemset.
721  */
722  template<typename _ForwardIterator, typename _Tp>
723  inline void
724  fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value)
725  {
726  // concept requirements
727  __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
728  _ForwardIterator>)
729  __glibcxx_requires_valid_range(__first, __last);
730 
731  std::__fill_a(std::__niter_base(__first), std::__niter_base(__last),
732  __value);
733  }
734 
735  template<typename _OutputIterator, typename _Size, typename _Tp>
736  inline typename
737  __gnu_cxx::__enable_if<!__is_scalar<_Tp>::__value, _OutputIterator>::__type
738  __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value)
739  {
740  for (__decltype(__n + 0) __niter = __n;
741  __niter > 0; --__niter, ++__first)
742  *__first = __value;
743  return __first;
744  }
745 
746  template<typename _OutputIterator, typename _Size, typename _Tp>
747  inline typename
748  __gnu_cxx::__enable_if<__is_scalar<_Tp>::__value, _OutputIterator>::__type
749  __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value)
750  {
751  const _Tp __tmp = __value;
752  for (__decltype(__n + 0) __niter = __n;
753  __niter > 0; --__niter, ++__first)
754  *__first = __tmp;
755  return __first;
756  }
757 
758  template<typename _Size, typename _Tp>
759  inline typename
760  __gnu_cxx::__enable_if<__is_byte<_Tp>::__value, _Tp*>::__type
761  __fill_n_a(_Tp* __first, _Size __n, const _Tp& __c)
762  {
763  std::__fill_a(__first, __first + __n, __c);
764  return __first + __n;
765  }
766 
767  /**
768  * @brief Fills the range [first,first+n) with copies of value.
769  * @ingroup mutating_algorithms
770  * @param __first An output iterator.
771  * @param __n The count of copies to perform.
772  * @param __value A reference-to-const of arbitrary type.
773  * @return The iterator at first+n.
774  *
775  * This function fills a range with copies of the same value. For char
776  * types filling contiguous areas of memory, this becomes an inline call
777  * to @c memset or @ wmemset.
778  *
779  * _GLIBCXX_RESOLVE_LIB_DEFECTS
780  * DR 865. More algorithms that throw away information
781  */
782  template<typename _OI, typename _Size, typename _Tp>
783  inline _OI
784  fill_n(_OI __first, _Size __n, const _Tp& __value)
785  {
786  // concept requirements
787  __glibcxx_function_requires(_OutputIteratorConcept<_OI, _Tp>)
788 
789  return _OI(std::__fill_n_a(std::__niter_base(__first), __n, __value));
790  }
791 
792  template<bool _BoolType>
793  struct __equal
794  {
795  template<typename _II1, typename _II2>
796  static bool
797  equal(_II1 __first1, _II1 __last1, _II2 __first2)
798  {
799  for (; __first1 != __last1; ++__first1, (void)++__first2)
800  if (!(*__first1 == *__first2))
801  return false;
802  return true;
803  }
804  };
805 
806  template<>
807  struct __equal<true>
808  {
809  template<typename _Tp>
810  static bool
811  equal(const _Tp* __first1, const _Tp* __last1, const _Tp* __first2)
812  {
813  if (const size_t __len = (__last1 - __first1))
814  return !__builtin_memcmp(__first1, __first2, sizeof(_Tp) * __len);
815  return true;
816  }
817  };
818 
819  template<typename _II1, typename _II2>
820  inline bool
821  __equal_aux(_II1 __first1, _II1 __last1, _II2 __first2)
822  {
823  typedef typename iterator_traits<_II1>::value_type _ValueType1;
824  typedef typename iterator_traits<_II2>::value_type _ValueType2;
825  const bool __simple = ((__is_integer<_ValueType1>::__value
826  || __is_pointer<_ValueType1>::__value)
827  && __is_pointer<_II1>::__value
828  && __is_pointer<_II2>::__value
829  && __are_same<_ValueType1, _ValueType2>::__value);
830 
831  return std::__equal<__simple>::equal(__first1, __last1, __first2);
832  }
833 
834  template<typename, typename>
835  struct __lc_rai
836  {
837  template<typename _II1, typename _II2>
838  static _II1
839  __newlast1(_II1, _II1 __last1, _II2, _II2)
840  { return __last1; }
841 
842  template<typename _II>
843  static bool
844  __cnd2(_II __first, _II __last)
845  { return __first != __last; }
846  };
847 
848  template<>
849  struct __lc_rai<random_access_iterator_tag, random_access_iterator_tag>
850  {
851  template<typename _RAI1, typename _RAI2>
852  static _RAI1
853  __newlast1(_RAI1 __first1, _RAI1 __last1,
854  _RAI2 __first2, _RAI2 __last2)
855  {
856  const typename iterator_traits<_RAI1>::difference_type
857  __diff1 = __last1 - __first1;
858  const typename iterator_traits<_RAI2>::difference_type
859  __diff2 = __last2 - __first2;
860  return __diff2 < __diff1 ? __first1 + __diff2 : __last1;
861  }
862 
863  template<typename _RAI>
864  static bool
865  __cnd2(_RAI, _RAI)
866  { return true; }
867  };
868 
869  template<typename _II1, typename _II2, typename _Compare>
870  bool
871  __lexicographical_compare_impl(_II1 __first1, _II1 __last1,
872  _II2 __first2, _II2 __last2,
873  _Compare __comp)
874  {
875  typedef typename iterator_traits<_II1>::iterator_category _Category1;
876  typedef typename iterator_traits<_II2>::iterator_category _Category2;
877  typedef std::__lc_rai<_Category1, _Category2> __rai_type;
878 
879  __last1 = __rai_type::__newlast1(__first1, __last1, __first2, __last2);
880  for (; __first1 != __last1 && __rai_type::__cnd2(__first2, __last2);
881  ++__first1, (void)++__first2)
882  {
883  if (__comp(__first1, __first2))
884  return true;
885  if (__comp(__first2, __first1))
886  return false;
887  }
888  return __first1 == __last1 && __first2 != __last2;
889  }
890 
891  template<bool _BoolType>
892  struct __lexicographical_compare
893  {
894  template<typename _II1, typename _II2>
895  static bool __lc(_II1, _II1, _II2, _II2);
896  };
897 
898  template<bool _BoolType>
899  template<typename _II1, typename _II2>
900  bool
901  __lexicographical_compare<_BoolType>::
902  __lc(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
903  {
904  return std::__lexicographical_compare_impl(__first1, __last1,
905  __first2, __last2,
906  __gnu_cxx::__ops::__iter_less_iter());
907  }
908 
909  template<>
910  struct __lexicographical_compare<true>
911  {
912  template<typename _Tp, typename _Up>
913  static bool
914  __lc(const _Tp* __first1, const _Tp* __last1,
915  const _Up* __first2, const _Up* __last2)
916  {
917  const size_t __len1 = __last1 - __first1;
918  const size_t __len2 = __last2 - __first2;
919  if (const size_t __len = std::min(__len1, __len2))
920  if (int __result = __builtin_memcmp(__first1, __first2, __len))
921  return __result < 0;
922  return __len1 < __len2;
923  }
924  };
925 
926  template<typename _II1, typename _II2>
927  inline bool
928  __lexicographical_compare_aux(_II1 __first1, _II1 __last1,
929  _II2 __first2, _II2 __last2)
930  {
931  typedef typename iterator_traits<_II1>::value_type _ValueType1;
932  typedef typename iterator_traits<_II2>::value_type _ValueType2;
933  const bool __simple =
934  (__is_byte<_ValueType1>::__value && __is_byte<_ValueType2>::__value
935  && !__gnu_cxx::__numeric_traits<_ValueType1>::__is_signed
936  && !__gnu_cxx::__numeric_traits<_ValueType2>::__is_signed
937  && __is_pointer<_II1>::__value
938  && __is_pointer<_II2>::__value);
939 
940  return std::__lexicographical_compare<__simple>::__lc(__first1, __last1,
941  __first2, __last2);
942  }
943 
944  template<typename _ForwardIterator, typename _Tp, typename _Compare>
945  _ForwardIterator
946  __lower_bound(_ForwardIterator __first, _ForwardIterator __last,
947  const _Tp& __val, _Compare __comp)
948  {
949  typedef typename iterator_traits<_ForwardIterator>::difference_type
950  _DistanceType;
951 
952  _DistanceType __len = std::distance(__first, __last);
953 
954  while (__len > 0)
955  {
956  _DistanceType __half = __len >> 1;
957  _ForwardIterator __middle = __first;
958  std::advance(__middle, __half);
959  if (__comp(__middle, __val))
960  {
961  __first = __middle;
962  ++__first;
963  __len = __len - __half - 1;
964  }
965  else
966  __len = __half;
967  }
968  return __first;
969  }
970 
971  /**
972  * @brief Finds the first position in which @a val could be inserted
973  * without changing the ordering.
974  * @param __first An iterator.
975  * @param __last Another iterator.
976  * @param __val The search term.
977  * @return An iterator pointing to the first element <em>not less
978  * than</em> @a val, or end() if every element is less than
979  * @a val.
980  * @ingroup binary_search_algorithms
981  */
982  template<typename _ForwardIterator, typename _Tp>
983  inline _ForwardIterator
984  lower_bound(_ForwardIterator __first, _ForwardIterator __last,
985  const _Tp& __val)
986  {
987  // concept requirements
988  __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
989  __glibcxx_function_requires(_LessThanOpConcept<
990  typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
991  __glibcxx_requires_partitioned_lower(__first, __last, __val);
992 
993  return std::__lower_bound(__first, __last, __val,
994  __gnu_cxx::__ops::__iter_less_val());
995  }
996 
997  /// This is a helper function for the sort routines and for random.tcc.
998  // Precondition: __n > 0.
999  inline _GLIBCXX_CONSTEXPR int
1000  __lg(int __n)
1001  { return sizeof(int) * __CHAR_BIT__ - 1 - __builtin_clz(__n); }
1002 
1003  inline _GLIBCXX_CONSTEXPR unsigned
1004  __lg(unsigned __n)
1005  { return sizeof(int) * __CHAR_BIT__ - 1 - __builtin_clz(__n); }
1006 
1007  inline _GLIBCXX_CONSTEXPR long
1008  __lg(long __n)
1009  { return sizeof(long) * __CHAR_BIT__ - 1 - __builtin_clzl(__n); }
1010 
1011  inline _GLIBCXX_CONSTEXPR unsigned long
1012  __lg(unsigned long __n)
1013  { return sizeof(long) * __CHAR_BIT__ - 1 - __builtin_clzl(__n); }
1014 
1015  inline _GLIBCXX_CONSTEXPR long long
1016  __lg(long long __n)
1017  { return sizeof(long long) * __CHAR_BIT__ - 1 - __builtin_clzll(__n); }
1018 
1019  inline _GLIBCXX_CONSTEXPR unsigned long long
1020  __lg(unsigned long long __n)
1021  { return sizeof(long long) * __CHAR_BIT__ - 1 - __builtin_clzll(__n); }
1022 
1023 _GLIBCXX_END_NAMESPACE_VERSION
1024 
1025 _GLIBCXX_BEGIN_NAMESPACE_ALGO
1026 
1027  /**
1028  * @brief Tests a range for element-wise equality.
1029  * @ingroup non_mutating_algorithms
1030  * @param __first1 An input iterator.
1031  * @param __last1 An input iterator.
1032  * @param __first2 An input iterator.
1033  * @return A boolean true or false.
1034  *
1035  * This compares the elements of two ranges using @c == and returns true or
1036  * false depending on whether all of the corresponding elements of the
1037  * ranges are equal.
1038  */
1039  template<typename _II1, typename _II2>
1040  inline bool
1041  equal(_II1 __first1, _II1 __last1, _II2 __first2)
1042  {
1043  // concept requirements
1044  __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1045  __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1046  __glibcxx_function_requires(_EqualOpConcept<
1047  typename iterator_traits<_II1>::value_type,
1048  typename iterator_traits<_II2>::value_type>)
1049  __glibcxx_requires_valid_range(__first1, __last1);
1050 
1051  return std::__equal_aux(std::__niter_base(__first1),
1052  std::__niter_base(__last1),
1053  std::__niter_base(__first2));
1054  }
1055 
1056  /**
1057  * @brief Tests a range for element-wise equality.
1058  * @ingroup non_mutating_algorithms
1059  * @param __first1 An input iterator.
1060  * @param __last1 An input iterator.
1061  * @param __first2 An input iterator.
1062  * @param __binary_pred A binary predicate @link functors
1063  * functor@endlink.
1064  * @return A boolean true or false.
1065  *
1066  * This compares the elements of two ranges using the binary_pred
1067  * parameter, and returns true or
1068  * false depending on whether all of the corresponding elements of the
1069  * ranges are equal.
1070  */
1071  template<typename _IIter1, typename _IIter2, typename _BinaryPredicate>
1072  inline bool
1073  equal(_IIter1 __first1, _IIter1 __last1,
1074  _IIter2 __first2, _BinaryPredicate __binary_pred)
1075  {
1076  // concept requirements
1077  __glibcxx_function_requires(_InputIteratorConcept<_IIter1>)
1078  __glibcxx_function_requires(_InputIteratorConcept<_IIter2>)
1079  __glibcxx_requires_valid_range(__first1, __last1);
1080 
1081  for (; __first1 != __last1; ++__first1, (void)++__first2)
1082  if (!bool(__binary_pred(*__first1, *__first2)))
1083  return false;
1084  return true;
1085  }
1086 
1087 #if __cplusplus > 201103L
1088 
1089 #define __cpp_lib_robust_nonmodifying_seq_ops 201304
1090 
1091  /**
1092  * @brief Tests a range for element-wise equality.
1093  * @ingroup non_mutating_algorithms
1094  * @param __first1 An input iterator.
1095  * @param __last1 An input iterator.
1096  * @param __first2 An input iterator.
1097  * @param __last2 An input iterator.
1098  * @return A boolean true or false.
1099  *
1100  * This compares the elements of two ranges using @c == and returns true or
1101  * false depending on whether all of the corresponding elements of the
1102  * ranges are equal.
1103  */
1104  template<typename _II1, typename _II2>
1105  inline bool
1106  equal(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
1107  {
1108  // concept requirements
1109  __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1110  __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1111  __glibcxx_function_requires(_EqualOpConcept<
1112  typename iterator_traits<_II1>::value_type,
1113  typename iterator_traits<_II2>::value_type>)
1114  __glibcxx_requires_valid_range(__first1, __last1);
1115  __glibcxx_requires_valid_range(__first2, __last2);
1116 
1117  using _RATag = random_access_iterator_tag;
1118  using _Cat1 = typename iterator_traits<_II1>::iterator_category;
1119  using _Cat2 = typename iterator_traits<_II2>::iterator_category;
1120  using _RAIters = __and_<is_same<_Cat1, _RATag>, is_same<_Cat2, _RATag>>;
1121  if (_RAIters())
1122  {
1123  auto __d1 = std::distance(__first1, __last1);
1124  auto __d2 = std::distance(__first2, __last2);
1125  if (__d1 != __d2)
1126  return false;
1127  return _GLIBCXX_STD_A::equal(__first1, __last1, __first2);
1128  }
1129 
1130  for (; __first1 != __last1 && __first2 != __last2;
1131  ++__first1, (void)++__first2)
1132  if (!(*__first1 == *__first2))
1133  return false;
1134  return __first1 == __last1 && __first2 == __last2;
1135  }
1136 
1137  /**
1138  * @brief Tests a range for element-wise equality.
1139  * @ingroup non_mutating_algorithms
1140  * @param __first1 An input iterator.
1141  * @param __last1 An input iterator.
1142  * @param __first2 An input iterator.
1143  * @param __last2 An input iterator.
1144  * @param __binary_pred A binary predicate @link functors
1145  * functor@endlink.
1146  * @return A boolean true or false.
1147  *
1148  * This compares the elements of two ranges using the binary_pred
1149  * parameter, and returns true or
1150  * false depending on whether all of the corresponding elements of the
1151  * ranges are equal.
1152  */
1153  template<typename _IIter1, typename _IIter2, typename _BinaryPredicate>
1154  inline bool
1155  equal(_IIter1 __first1, _IIter1 __last1,
1156  _IIter2 __first2, _IIter2 __last2, _BinaryPredicate __binary_pred)
1157  {
1158  // concept requirements
1159  __glibcxx_function_requires(_InputIteratorConcept<_IIter1>)
1160  __glibcxx_function_requires(_InputIteratorConcept<_IIter2>)
1161  __glibcxx_requires_valid_range(__first1, __last1);
1162  __glibcxx_requires_valid_range(__first2, __last2);
1163 
1164  using _RATag = random_access_iterator_tag;
1165  using _Cat1 = typename iterator_traits<_IIter1>::iterator_category;
1166  using _Cat2 = typename iterator_traits<_IIter2>::iterator_category;
1167  using _RAIters = __and_<is_same<_Cat1, _RATag>, is_same<_Cat2, _RATag>>;
1168  if (_RAIters())
1169  {
1170  auto __d1 = std::distance(__first1, __last1);
1171  auto __d2 = std::distance(__first2, __last2);
1172  if (__d1 != __d2)
1173  return false;
1174  return _GLIBCXX_STD_A::equal(__first1, __last1, __first2,
1175  __binary_pred);
1176  }
1177 
1178  for (; __first1 != __last1 && __first2 != __last2;
1179  ++__first1, (void)++__first2)
1180  if (!bool(__binary_pred(*__first1, *__first2)))
1181  return false;
1182  return __first1 == __last1 && __first2 == __last2;
1183  }
1184 #endif
1185 
1186  /**
1187  * @brief Performs @b dictionary comparison on ranges.
1188  * @ingroup sorting_algorithms
1189  * @param __first1 An input iterator.
1190  * @param __last1 An input iterator.
1191  * @param __first2 An input iterator.
1192  * @param __last2 An input iterator.
1193  * @return A boolean true or false.
1194  *
1195  * <em>Returns true if the sequence of elements defined by the range
1196  * [first1,last1) is lexicographically less than the sequence of elements
1197  * defined by the range [first2,last2). Returns false otherwise.</em>
1198  * (Quoted from [25.3.8]/1.) If the iterators are all character pointers,
1199  * then this is an inline call to @c memcmp.
1200  */
1201  template<typename _II1, typename _II2>
1202  inline bool
1203  lexicographical_compare(_II1 __first1, _II1 __last1,
1204  _II2 __first2, _II2 __last2)
1205  {
1206 #ifdef _GLIBCXX_CONCEPT_CHECKS
1207  // concept requirements
1208  typedef typename iterator_traits<_II1>::value_type _ValueType1;
1209  typedef typename iterator_traits<_II2>::value_type _ValueType2;
1210 #endif
1211  __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1212  __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1213  __glibcxx_function_requires(_LessThanOpConcept<_ValueType1, _ValueType2>)
1214  __glibcxx_function_requires(_LessThanOpConcept<_ValueType2, _ValueType1>)
1215  __glibcxx_requires_valid_range(__first1, __last1);
1216  __glibcxx_requires_valid_range(__first2, __last2);
1217 
1218  return std::__lexicographical_compare_aux(std::__niter_base(__first1),
1219  std::__niter_base(__last1),
1220  std::__niter_base(__first2),
1221  std::__niter_base(__last2));
1222  }
1223 
1224  /**
1225  * @brief Performs @b dictionary comparison on ranges.
1226  * @ingroup sorting_algorithms
1227  * @param __first1 An input iterator.
1228  * @param __last1 An input iterator.
1229  * @param __first2 An input iterator.
1230  * @param __last2 An input iterator.
1231  * @param __comp A @link comparison_functors comparison functor@endlink.
1232  * @return A boolean true or false.
1233  *
1234  * The same as the four-parameter @c lexicographical_compare, but uses the
1235  * comp parameter instead of @c <.
1236  */
1237  template<typename _II1, typename _II2, typename _Compare>
1238  inline bool
1239  lexicographical_compare(_II1 __first1, _II1 __last1,
1240  _II2 __first2, _II2 __last2, _Compare __comp)
1241  {
1242  // concept requirements
1243  __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1244  __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1245  __glibcxx_requires_valid_range(__first1, __last1);
1246  __glibcxx_requires_valid_range(__first2, __last2);
1247 
1248  return std::__lexicographical_compare_impl
1249  (__first1, __last1, __first2, __last2,
1250  __gnu_cxx::__ops::__iter_comp_iter(__comp));
1251  }
1252 
1253  template<typename _InputIterator1, typename _InputIterator2,
1254  typename _BinaryPredicate>
1256  __mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1257  _InputIterator2 __first2, _BinaryPredicate __binary_pred)
1258  {
1259  while (__first1 != __last1 && __binary_pred(__first1, __first2))
1260  {
1261  ++__first1;
1262  ++__first2;
1263  }
1264  return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
1265  }
1266 
1267  /**
1268  * @brief Finds the places in ranges which don't match.
1269  * @ingroup non_mutating_algorithms
1270  * @param __first1 An input iterator.
1271  * @param __last1 An input iterator.
1272  * @param __first2 An input iterator.
1273  * @return A pair of iterators pointing to the first mismatch.
1274  *
1275  * This compares the elements of two ranges using @c == and returns a pair
1276  * of iterators. The first iterator points into the first range, the
1277  * second iterator points into the second range, and the elements pointed
1278  * to by the iterators are not equal.
1279  */
1280  template<typename _InputIterator1, typename _InputIterator2>
1282  mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1283  _InputIterator2 __first2)
1284  {
1285  // concept requirements
1286  __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
1287  __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
1288  __glibcxx_function_requires(_EqualOpConcept<
1289  typename iterator_traits<_InputIterator1>::value_type,
1290  typename iterator_traits<_InputIterator2>::value_type>)
1291  __glibcxx_requires_valid_range(__first1, __last1);
1292 
1293  return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2,
1294  __gnu_cxx::__ops::__iter_equal_to_iter());
1295  }
1296 
1297  /**
1298  * @brief Finds the places in ranges which don't match.
1299  * @ingroup non_mutating_algorithms
1300  * @param __first1 An input iterator.
1301  * @param __last1 An input iterator.
1302  * @param __first2 An input iterator.
1303  * @param __binary_pred A binary predicate @link functors
1304  * functor@endlink.
1305  * @return A pair of iterators pointing to the first mismatch.
1306  *
1307  * This compares the elements of two ranges using the binary_pred
1308  * parameter, and returns a pair
1309  * of iterators. The first iterator points into the first range, the
1310  * second iterator points into the second range, and the elements pointed
1311  * to by the iterators are not equal.
1312  */
1313  template<typename _InputIterator1, typename _InputIterator2,
1314  typename _BinaryPredicate>
1316  mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1317  _InputIterator2 __first2, _BinaryPredicate __binary_pred)
1318  {
1319  // concept requirements
1320  __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
1321  __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
1322  __glibcxx_requires_valid_range(__first1, __last1);
1323 
1324  return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2,
1325  __gnu_cxx::__ops::__iter_comp_iter(__binary_pred));
1326  }
1327 
1328 #if __cplusplus > 201103L
1329 
1330  template<typename _InputIterator1, typename _InputIterator2,
1331  typename _BinaryPredicate>
1333  __mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1334  _InputIterator2 __first2, _InputIterator2 __last2,
1335  _BinaryPredicate __binary_pred)
1336  {
1337  while (__first1 != __last1 && __first2 != __last2
1338  && __binary_pred(__first1, __first2))
1339  {
1340  ++__first1;
1341  ++__first2;
1342  }
1343  return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
1344  }
1345 
1346  /**
1347  * @brief Finds the places in ranges which don't match.
1348  * @ingroup non_mutating_algorithms
1349  * @param __first1 An input iterator.
1350  * @param __last1 An input iterator.
1351  * @param __first2 An input iterator.
1352  * @param __last2 An input iterator.
1353  * @return A pair of iterators pointing to the first mismatch.
1354  *
1355  * This compares the elements of two ranges using @c == and returns a pair
1356  * of iterators. The first iterator points into the first range, the
1357  * second iterator points into the second range, and the elements pointed
1358  * to by the iterators are not equal.
1359  */
1360  template<typename _InputIterator1, typename _InputIterator2>
1362  mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1363  _InputIterator2 __first2, _InputIterator2 __last2)
1364  {
1365  // concept requirements
1366  __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
1367  __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
1368  __glibcxx_function_requires(_EqualOpConcept<
1369  typename iterator_traits<_InputIterator1>::value_type,
1370  typename iterator_traits<_InputIterator2>::value_type>)
1371  __glibcxx_requires_valid_range(__first1, __last1);
1372  __glibcxx_requires_valid_range(__first2, __last2);
1373 
1374  return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2, __last2,
1375  __gnu_cxx::__ops::__iter_equal_to_iter());
1376  }
1377 
1378  /**
1379  * @brief Finds the places in ranges which don't match.
1380  * @ingroup non_mutating_algorithms
1381  * @param __first1 An input iterator.
1382  * @param __last1 An input iterator.
1383  * @param __first2 An input iterator.
1384  * @param __last2 An input iterator.
1385  * @param __binary_pred A binary predicate @link functors
1386  * functor@endlink.
1387  * @return A pair of iterators pointing to the first mismatch.
1388  *
1389  * This compares the elements of two ranges using the binary_pred
1390  * parameter, and returns a pair
1391  * of iterators. The first iterator points into the first range, the
1392  * second iterator points into the second range, and the elements pointed
1393  * to by the iterators are not equal.
1394  */
1395  template<typename _InputIterator1, typename _InputIterator2,
1396  typename _BinaryPredicate>
1398  mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1399  _InputIterator2 __first2, _InputIterator2 __last2,
1400  _BinaryPredicate __binary_pred)
1401  {
1402  // concept requirements
1403  __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
1404  __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
1405  __glibcxx_requires_valid_range(__first1, __last1);
1406  __glibcxx_requires_valid_range(__first2, __last2);
1407 
1408  return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2, __last2,
1409  __gnu_cxx::__ops::__iter_comp_iter(__binary_pred));
1410  }
1411 #endif
1412 
1413 _GLIBCXX_END_NAMESPACE_ALGO
1414 } // namespace std
1415 
1416 // NB: This file is included within many other C++ includes, as a way
1417 // of getting the base algorithms. So, make sure that parallel bits
1418 // come in too if requested.
1419 #ifdef _GLIBCXX_PARALLEL
1420 # include <parallel/algobase.h>
1421 #endif
1422 
1423 #endif
constexpr int __lg(int __n)
This is a helper function for the sort routines and for random.tcc.
Provides output iterator semantics for streambufs.
Definition: iosfwd:128
_OI copy(_II __first, _II __last, _OI __result)
Copies the range [first,last) into result.
Definition: stl_algobase.h:446
void iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
Swaps the contents of two iterators.
Definition: stl_algobase.h:120
ISO C++ entities toplevel namespace is std.
_GLIBCXX17_CONSTEXPR iterator_traits< _InputIterator >::difference_type distance(_InputIterator __first, _InputIterator __last)
A generalization of pointer arithmetic.
_GLIBCXX14_CONSTEXPR const _Tp & max(const _Tp &, const _Tp &)
This does what you think it does.
Definition: stl_algobase.h:219
_GLIBCXX17_CONSTEXPR void advance(_InputIterator &__i, _Distance __n)
A generalization of pointer arithmetic.
Provides input iterator semantics for streambufs.
Definition: iosfwd:125
_OI move(_II __first, _II __last, _OI __result)
Moves the range [first,last) into result.
Definition: stl_algobase.h:479
Parallel STL function calls corresponding to the stl_algobase.h header. The functions defined here ma...
Basis for explicit traits specializations.
Definition: char_traits.h:269
_GLIBCXX14_CONSTEXPR const _Tp & min(const _Tp &, const _Tp &)
This does what you think it does.
Definition: stl_algobase.h:195
Struct holding two objects of arbitrary type.
Definition: stl_pair.h:198
bool equal(_IIter1 __first1, _IIter1 __last1, _IIter2 __first2, _IIter2 __last2, _BinaryPredicate __binary_pred)
Tests a range for element-wise equality.