libstdc++
stl_algobase.h
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1 // Core algorithmic facilities -*- C++ -*-
2 
3 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
4 // 2011 Free Software Foundation, Inc.
5 //
6 // This file is part of the GNU ISO C++ Library. This library is free
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11 
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16 
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25 
26 /*
27  *
28  * Copyright (c) 1994
29  * Hewlett-Packard Company
30  *
31  * Permission to use, copy, modify, distribute and sell this software
32  * and its documentation for any purpose is hereby granted without fee,
33  * provided that the above copyright notice appear in all copies and
34  * that both that copyright notice and this permission notice appear
35  * in supporting documentation. Hewlett-Packard Company makes no
36  * representations about the suitability of this software for any
37  * purpose. It is provided "as is" without express or implied warranty.
38  *
39  *
40  * Copyright (c) 1996-1998
41  * Silicon Graphics Computer Systems, Inc.
42  *
43  * Permission to use, copy, modify, distribute and sell this software
44  * and its documentation for any purpose is hereby granted without fee,
45  * provided that the above copyright notice appear in all copies and
46  * that both that copyright notice and this permission notice appear
47  * in supporting documentation. Silicon Graphics makes no
48  * representations about the suitability of this software for any
49  * purpose. It is provided "as is" without express or implied warranty.
50  */
51 
52 /** @file bits/stl_algobase.h
53  * This is an internal header file, included by other library headers.
54  * Do not attempt to use it directly. @headername{algorithm}
55  */
56 
57 #ifndef _STL_ALGOBASE_H
58 #define _STL_ALGOBASE_H 1
59 
60 #include <bits/c++config.h>
61 #include <bits/functexcept.h>
62 #include <bits/cpp_type_traits.h>
63 #include <ext/type_traits.h>
64 #include <ext/numeric_traits.h>
65 #include <bits/stl_pair.h>
66 #include <bits/stl_iterator_base_types.h>
67 #include <bits/stl_iterator_base_funcs.h>
68 #include <bits/stl_iterator.h>
69 #include <bits/concept_check.h>
70 #include <debug/debug.h>
71 #include <bits/move.h> // For std::swap and _GLIBCXX_MOVE
72 
73 namespace std _GLIBCXX_VISIBILITY(default)
74 {
75 _GLIBCXX_BEGIN_NAMESPACE_VERSION
76 
77  // See http://gcc.gnu.org/ml/libstdc++/2004-08/msg00167.html: in a
78  // nutshell, we are partially implementing the resolution of DR 187,
79  // when it's safe, i.e., the value_types are equal.
80  template<bool _BoolType>
81  struct __iter_swap
82  {
83  template<typename _ForwardIterator1, typename _ForwardIterator2>
84  static void
85  iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
86  {
87  typedef typename iterator_traits<_ForwardIterator1>::value_type
88  _ValueType1;
89  _ValueType1 __tmp = _GLIBCXX_MOVE(*__a);
90  *__a = _GLIBCXX_MOVE(*__b);
91  *__b = _GLIBCXX_MOVE(__tmp);
92  }
93  };
94 
95  template<>
96  struct __iter_swap<true>
97  {
98  template<typename _ForwardIterator1, typename _ForwardIterator2>
99  static void
100  iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
101  {
102  swap(*__a, *__b);
103  }
104  };
105 
106  /**
107  * @brief Swaps the contents of two iterators.
108  * @ingroup mutating_algorithms
109  * @param __a An iterator.
110  * @param __b Another iterator.
111  * @return Nothing.
112  *
113  * This function swaps the values pointed to by two iterators, not the
114  * iterators themselves.
115  */
116  template<typename _ForwardIterator1, typename _ForwardIterator2>
117  inline void
118  iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
119  {
120  typedef typename iterator_traits<_ForwardIterator1>::value_type
121  _ValueType1;
122  typedef typename iterator_traits<_ForwardIterator2>::value_type
123  _ValueType2;
124 
125  // concept requirements
126  __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
127  _ForwardIterator1>)
128  __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
129  _ForwardIterator2>)
130  __glibcxx_function_requires(_ConvertibleConcept<_ValueType1,
131  _ValueType2>)
132  __glibcxx_function_requires(_ConvertibleConcept<_ValueType2,
133  _ValueType1>)
134 
135  typedef typename iterator_traits<_ForwardIterator1>::reference
136  _ReferenceType1;
137  typedef typename iterator_traits<_ForwardIterator2>::reference
138  _ReferenceType2;
139  std::__iter_swap<__are_same<_ValueType1, _ValueType2>::__value
140  && __are_same<_ValueType1&, _ReferenceType1>::__value
141  && __are_same<_ValueType2&, _ReferenceType2>::__value>::
142  iter_swap(__a, __b);
143  }
144 
145  /**
146  * @brief Swap the elements of two sequences.
147  * @ingroup mutating_algorithms
148  * @param __first1 A forward iterator.
149  * @param __last1 A forward iterator.
150  * @param __first2 A forward iterator.
151  * @return An iterator equal to @p first2+(last1-first1).
152  *
153  * Swaps each element in the range @p [first1,last1) with the
154  * corresponding element in the range @p [first2,(last1-first1)).
155  * The ranges must not overlap.
156  */
157  template<typename _ForwardIterator1, typename _ForwardIterator2>
158  _ForwardIterator2
159  swap_ranges(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
160  _ForwardIterator2 __first2)
161  {
162  // concept requirements
163  __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
164  _ForwardIterator1>)
165  __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
166  _ForwardIterator2>)
167  __glibcxx_requires_valid_range(__first1, __last1);
168 
169  for (; __first1 != __last1; ++__first1, ++__first2)
170  std::iter_swap(__first1, __first2);
171  return __first2;
172  }
173 
174  /**
175  * @brief This does what you think it does.
176  * @ingroup sorting_algorithms
177  * @param __a A thing of arbitrary type.
178  * @param __b Another thing of arbitrary type.
179  * @return The lesser of the parameters.
180  *
181  * This is the simple classic generic implementation. It will work on
182  * temporary expressions, since they are only evaluated once, unlike a
183  * preprocessor macro.
184  */
185  template<typename _Tp>
186  inline const _Tp&
187  min(const _Tp& __a, const _Tp& __b)
188  {
189  // concept requirements
190  __glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
191  //return __b < __a ? __b : __a;
192  if (__b < __a)
193  return __b;
194  return __a;
195  }
196 
197  /**
198  * @brief This does what you think it does.
199  * @ingroup sorting_algorithms
200  * @param __a A thing of arbitrary type.
201  * @param __b Another thing of arbitrary type.
202  * @return The greater of the parameters.
203  *
204  * This is the simple classic generic implementation. It will work on
205  * temporary expressions, since they are only evaluated once, unlike a
206  * preprocessor macro.
207  */
208  template<typename _Tp>
209  inline const _Tp&
210  max(const _Tp& __a, const _Tp& __b)
211  {
212  // concept requirements
213  __glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
214  //return __a < __b ? __b : __a;
215  if (__a < __b)
216  return __b;
217  return __a;
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  * @param __comp A @link comparison_functors comparison functor@endlink.
226  * @return The lesser of the parameters.
227  *
228  * This will work on temporary expressions, since they are only evaluated
229  * once, unlike a preprocessor macro.
230  */
231  template<typename _Tp, typename _Compare>
232  inline const _Tp&
233  min(const _Tp& __a, const _Tp& __b, _Compare __comp)
234  {
235  //return __comp(__b, __a) ? __b : __a;
236  if (__comp(__b, __a))
237  return __b;
238  return __a;
239  }
240 
241  /**
242  * @brief This does what you think it does.
243  * @ingroup sorting_algorithms
244  * @param __a A thing of arbitrary type.
245  * @param __b Another thing of arbitrary type.
246  * @param __comp A @link comparison_functors comparison functor@endlink.
247  * @return The greater of the parameters.
248  *
249  * This will work on temporary expressions, since they are only evaluated
250  * once, unlike a preprocessor macro.
251  */
252  template<typename _Tp, typename _Compare>
253  inline const _Tp&
254  max(const _Tp& __a, const _Tp& __b, _Compare __comp)
255  {
256  //return __comp(__a, __b) ? __b : __a;
257  if (__comp(__a, __b))
258  return __b;
259  return __a;
260  }
261 
262  // If _Iterator is a __normal_iterator return its base (a plain pointer,
263  // normally) otherwise return it untouched. See copy, fill, ...
264  template<typename _Iterator>
265  struct _Niter_base
266  : _Iter_base<_Iterator, __is_normal_iterator<_Iterator>::__value>
267  { };
268 
269  template<typename _Iterator>
270  inline typename _Niter_base<_Iterator>::iterator_type
271  __niter_base(_Iterator __it)
272  { return std::_Niter_base<_Iterator>::_S_base(__it); }
273 
274  // Likewise, for move_iterator.
275  template<typename _Iterator>
276  struct _Miter_base
277  : _Iter_base<_Iterator, __is_move_iterator<_Iterator>::__value>
278  { };
279 
280  template<typename _Iterator>
281  inline typename _Miter_base<_Iterator>::iterator_type
282  __miter_base(_Iterator __it)
283  { return std::_Miter_base<_Iterator>::_S_base(__it); }
284 
285  // All of these auxiliary structs serve two purposes. (1) Replace
286  // calls to copy with memmove whenever possible. (Memmove, not memcpy,
287  // because the input and output ranges are permitted to overlap.)
288  // (2) If we're using random access iterators, then write the loop as
289  // a for loop with an explicit count.
290 
291  template<bool, bool, typename>
292  struct __copy_move
293  {
294  template<typename _II, typename _OI>
295  static _OI
296  __copy_m(_II __first, _II __last, _OI __result)
297  {
298  for (; __first != __last; ++__result, ++__first)
299  *__result = *__first;
300  return __result;
301  }
302  };
303 
304 #ifdef __GXX_EXPERIMENTAL_CXX0X__
305  template<typename _Category>
306  struct __copy_move<true, false, _Category>
307  {
308  template<typename _II, typename _OI>
309  static _OI
310  __copy_m(_II __first, _II __last, _OI __result)
311  {
312  for (; __first != __last; ++__result, ++__first)
313  *__result = std::move(*__first);
314  return __result;
315  }
316  };
317 #endif
318 
319  template<>
320  struct __copy_move<false, false, random_access_iterator_tag>
321  {
322  template<typename _II, typename _OI>
323  static _OI
324  __copy_m(_II __first, _II __last, _OI __result)
325  {
326  typedef typename iterator_traits<_II>::difference_type _Distance;
327  for(_Distance __n = __last - __first; __n > 0; --__n)
328  {
329  *__result = *__first;
330  ++__first;
331  ++__result;
332  }
333  return __result;
334  }
335  };
336 
337 #ifdef __GXX_EXPERIMENTAL_CXX0X__
338  template<>
339  struct __copy_move<true, false, random_access_iterator_tag>
340  {
341  template<typename _II, typename _OI>
342  static _OI
343  __copy_m(_II __first, _II __last, _OI __result)
344  {
345  typedef typename iterator_traits<_II>::difference_type _Distance;
346  for(_Distance __n = __last - __first; __n > 0; --__n)
347  {
348  *__result = std::move(*__first);
349  ++__first;
350  ++__result;
351  }
352  return __result;
353  }
354  };
355 #endif
356 
357  template<bool _IsMove>
358  struct __copy_move<_IsMove, true, random_access_iterator_tag>
359  {
360  template<typename _Tp>
361  static _Tp*
362  __copy_m(const _Tp* __first, const _Tp* __last, _Tp* __result)
363  {
364  const ptrdiff_t _Num = __last - __first;
365  if (_Num)
366  __builtin_memmove(__result, __first, sizeof(_Tp) * _Num);
367  return __result + _Num;
368  }
369  };
370 
371  template<bool _IsMove, typename _II, typename _OI>
372  inline _OI
373  __copy_move_a(_II __first, _II __last, _OI __result)
374  {
375  typedef typename iterator_traits<_II>::value_type _ValueTypeI;
376  typedef typename iterator_traits<_OI>::value_type _ValueTypeO;
377  typedef typename iterator_traits<_II>::iterator_category _Category;
378  const bool __simple = (__is_trivial(_ValueTypeI)
379  && __is_pointer<_II>::__value
380  && __is_pointer<_OI>::__value
381  && __are_same<_ValueTypeI, _ValueTypeO>::__value);
382 
383  return std::__copy_move<_IsMove, __simple,
384  _Category>::__copy_m(__first, __last, __result);
385  }
386 
387  // Helpers for streambuf iterators (either istream or ostream).
388  // NB: avoid including <iosfwd>, relatively large.
389  template<typename _CharT>
390  struct char_traits;
391 
392  template<typename _CharT, typename _Traits>
393  class istreambuf_iterator;
394 
395  template<typename _CharT, typename _Traits>
396  class ostreambuf_iterator;
397 
398  template<bool _IsMove, typename _CharT>
399  typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
400  ostreambuf_iterator<_CharT, char_traits<_CharT> > >::__type
401  __copy_move_a2(_CharT*, _CharT*,
402  ostreambuf_iterator<_CharT, char_traits<_CharT> >);
403 
404  template<bool _IsMove, typename _CharT>
405  typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
406  ostreambuf_iterator<_CharT, char_traits<_CharT> > >::__type
407  __copy_move_a2(const _CharT*, const _CharT*,
408  ostreambuf_iterator<_CharT, char_traits<_CharT> >);
409 
410  template<bool _IsMove, typename _CharT>
411  typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
412  _CharT*>::__type
413  __copy_move_a2(istreambuf_iterator<_CharT, char_traits<_CharT> >,
414  istreambuf_iterator<_CharT, char_traits<_CharT> >, _CharT*);
415 
416  template<bool _IsMove, typename _II, typename _OI>
417  inline _OI
418  __copy_move_a2(_II __first, _II __last, _OI __result)
419  {
420  return _OI(std::__copy_move_a<_IsMove>(std::__niter_base(__first),
421  std::__niter_base(__last),
422  std::__niter_base(__result)));
423  }
424 
425  /**
426  * @brief Copies the range [first,last) into result.
427  * @ingroup mutating_algorithms
428  * @param __first An input iterator.
429  * @param __last An input iterator.
430  * @param __result An output iterator.
431  * @return result + (first - last)
432  *
433  * This inline function will boil down to a call to @c memmove whenever
434  * possible. Failing that, if random access iterators are passed, then the
435  * loop count will be known (and therefore a candidate for compiler
436  * optimizations such as unrolling). Result may not be contained within
437  * [first,last); the copy_backward function should be used instead.
438  *
439  * Note that the end of the output range is permitted to be contained
440  * within [first,last).
441  */
442  template<typename _II, typename _OI>
443  inline _OI
444  copy(_II __first, _II __last, _OI __result)
445  {
446  // concept requirements
447  __glibcxx_function_requires(_InputIteratorConcept<_II>)
448  __glibcxx_function_requires(_OutputIteratorConcept<_OI,
449  typename iterator_traits<_II>::value_type>)
450  __glibcxx_requires_valid_range(__first, __last);
451 
452  return (std::__copy_move_a2<__is_move_iterator<_II>::__value>
453  (std::__miter_base(__first), std::__miter_base(__last),
454  __result));
455  }
456 
457 #ifdef __GXX_EXPERIMENTAL_CXX0X__
458  /**
459  * @brief Moves the range [first,last) into result.
460  * @ingroup mutating_algorithms
461  * @param __first An input iterator.
462  * @param __last An input iterator.
463  * @param __result An output iterator.
464  * @return result + (first - last)
465  *
466  * This inline function will boil down to a call to @c memmove whenever
467  * possible. Failing that, if random access iterators are passed, then the
468  * loop count will be known (and therefore a candidate for compiler
469  * optimizations such as unrolling). Result may not be contained within
470  * [first,last); the move_backward function should be used instead.
471  *
472  * Note that the end of the output range is permitted to be contained
473  * within [first,last).
474  */
475  template<typename _II, typename _OI>
476  inline _OI
477  move(_II __first, _II __last, _OI __result)
478  {
479  // concept requirements
480  __glibcxx_function_requires(_InputIteratorConcept<_II>)
481  __glibcxx_function_requires(_OutputIteratorConcept<_OI,
482  typename iterator_traits<_II>::value_type>)
483  __glibcxx_requires_valid_range(__first, __last);
484 
485  return std::__copy_move_a2<true>(std::__miter_base(__first),
486  std::__miter_base(__last), __result);
487  }
488 
489 #define _GLIBCXX_MOVE3(_Tp, _Up, _Vp) std::move(_Tp, _Up, _Vp)
490 #else
491 #define _GLIBCXX_MOVE3(_Tp, _Up, _Vp) std::copy(_Tp, _Up, _Vp)
492 #endif
493 
494  template<bool, bool, typename>
495  struct __copy_move_backward
496  {
497  template<typename _BI1, typename _BI2>
498  static _BI2
499  __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
500  {
501  while (__first != __last)
502  *--__result = *--__last;
503  return __result;
504  }
505  };
506 
507 #ifdef __GXX_EXPERIMENTAL_CXX0X__
508  template<typename _Category>
509  struct __copy_move_backward<true, false, _Category>
510  {
511  template<typename _BI1, typename _BI2>
512  static _BI2
513  __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
514  {
515  while (__first != __last)
516  *--__result = std::move(*--__last);
517  return __result;
518  }
519  };
520 #endif
521 
522  template<>
523  struct __copy_move_backward<false, false, random_access_iterator_tag>
524  {
525  template<typename _BI1, typename _BI2>
526  static _BI2
527  __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
528  {
529  typename iterator_traits<_BI1>::difference_type __n;
530  for (__n = __last - __first; __n > 0; --__n)
531  *--__result = *--__last;
532  return __result;
533  }
534  };
535 
536 #ifdef __GXX_EXPERIMENTAL_CXX0X__
537  template<>
538  struct __copy_move_backward<true, false, random_access_iterator_tag>
539  {
540  template<typename _BI1, typename _BI2>
541  static _BI2
542  __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
543  {
544  typename iterator_traits<_BI1>::difference_type __n;
545  for (__n = __last - __first; __n > 0; --__n)
546  *--__result = std::move(*--__last);
547  return __result;
548  }
549  };
550 #endif
551 
552  template<bool _IsMove>
553  struct __copy_move_backward<_IsMove, true, random_access_iterator_tag>
554  {
555  template<typename _Tp>
556  static _Tp*
557  __copy_move_b(const _Tp* __first, const _Tp* __last, _Tp* __result)
558  {
559  const ptrdiff_t _Num = __last - __first;
560  if (_Num)
561  __builtin_memmove(__result - _Num, __first, sizeof(_Tp) * _Num);
562  return __result - _Num;
563  }
564  };
565 
566  template<bool _IsMove, typename _BI1, typename _BI2>
567  inline _BI2
568  __copy_move_backward_a(_BI1 __first, _BI1 __last, _BI2 __result)
569  {
570  typedef typename iterator_traits<_BI1>::value_type _ValueType1;
571  typedef typename iterator_traits<_BI2>::value_type _ValueType2;
572  typedef typename iterator_traits<_BI1>::iterator_category _Category;
573  const bool __simple = (__is_trivial(_ValueType1)
574  && __is_pointer<_BI1>::__value
575  && __is_pointer<_BI2>::__value
576  && __are_same<_ValueType1, _ValueType2>::__value);
577 
578  return std::__copy_move_backward<_IsMove, __simple,
579  _Category>::__copy_move_b(__first,
580  __last,
581  __result);
582  }
583 
584  template<bool _IsMove, typename _BI1, typename _BI2>
585  inline _BI2
586  __copy_move_backward_a2(_BI1 __first, _BI1 __last, _BI2 __result)
587  {
588  return _BI2(std::__copy_move_backward_a<_IsMove>
589  (std::__niter_base(__first), std::__niter_base(__last),
590  std::__niter_base(__result)));
591  }
592 
593  /**
594  * @brief Copies the range [first,last) into result.
595  * @ingroup mutating_algorithms
596  * @param __first A bidirectional iterator.
597  * @param __last A bidirectional iterator.
598  * @param __result A bidirectional iterator.
599  * @return result - (first - last)
600  *
601  * The function has the same effect as copy, but starts at the end of the
602  * range and works its way to the start, returning the start of the result.
603  * This inline function will boil down to a call to @c memmove whenever
604  * possible. Failing that, if random access iterators are passed, then the
605  * loop count will be known (and therefore a candidate for compiler
606  * optimizations such as unrolling).
607  *
608  * Result may not be in the range [first,last). Use copy instead. Note
609  * that the start of the output range may overlap [first,last).
610  */
611  template<typename _BI1, typename _BI2>
612  inline _BI2
613  copy_backward(_BI1 __first, _BI1 __last, _BI2 __result)
614  {
615  // concept requirements
616  __glibcxx_function_requires(_BidirectionalIteratorConcept<_BI1>)
617  __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<_BI2>)
618  __glibcxx_function_requires(_ConvertibleConcept<
619  typename iterator_traits<_BI1>::value_type,
620  typename iterator_traits<_BI2>::value_type>)
621  __glibcxx_requires_valid_range(__first, __last);
622 
623  return (std::__copy_move_backward_a2<__is_move_iterator<_BI1>::__value>
624  (std::__miter_base(__first), std::__miter_base(__last),
625  __result));
626  }
627 
628 #ifdef __GXX_EXPERIMENTAL_CXX0X__
629  /**
630  * @brief Moves the range [first,last) into result.
631  * @ingroup mutating_algorithms
632  * @param __first A bidirectional iterator.
633  * @param __last A bidirectional iterator.
634  * @param __result A bidirectional iterator.
635  * @return result - (first - last)
636  *
637  * The function has the same effect as move, but starts at the end of the
638  * range and works its way to the start, returning the start of the result.
639  * This inline function will boil down to a call to @c memmove whenever
640  * possible. Failing that, if random access iterators are passed, then the
641  * loop count will be known (and therefore a candidate for compiler
642  * optimizations such as unrolling).
643  *
644  * Result may not be in the range (first,last]. Use move instead. Note
645  * that the start of the output range may overlap [first,last).
646  */
647  template<typename _BI1, typename _BI2>
648  inline _BI2
649  move_backward(_BI1 __first, _BI1 __last, _BI2 __result)
650  {
651  // concept requirements
652  __glibcxx_function_requires(_BidirectionalIteratorConcept<_BI1>)
653  __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<_BI2>)
654  __glibcxx_function_requires(_ConvertibleConcept<
655  typename iterator_traits<_BI1>::value_type,
656  typename iterator_traits<_BI2>::value_type>)
657  __glibcxx_requires_valid_range(__first, __last);
658 
659  return std::__copy_move_backward_a2<true>(std::__miter_base(__first),
660  std::__miter_base(__last),
661  __result);
662  }
663 
664 #define _GLIBCXX_MOVE_BACKWARD3(_Tp, _Up, _Vp) std::move_backward(_Tp, _Up, _Vp)
665 #else
666 #define _GLIBCXX_MOVE_BACKWARD3(_Tp, _Up, _Vp) std::copy_backward(_Tp, _Up, _Vp)
667 #endif
668 
669  template<typename _ForwardIterator, typename _Tp>
670  inline typename
671  __gnu_cxx::__enable_if<!__is_scalar<_Tp>::__value, void>::__type
672  __fill_a(_ForwardIterator __first, _ForwardIterator __last,
673  const _Tp& __value)
674  {
675  for (; __first != __last; ++__first)
676  *__first = __value;
677  }
678 
679  template<typename _ForwardIterator, typename _Tp>
680  inline typename
681  __gnu_cxx::__enable_if<__is_scalar<_Tp>::__value, void>::__type
682  __fill_a(_ForwardIterator __first, _ForwardIterator __last,
683  const _Tp& __value)
684  {
685  const _Tp __tmp = __value;
686  for (; __first != __last; ++__first)
687  *__first = __tmp;
688  }
689 
690  // Specialization: for char types we can use memset.
691  template<typename _Tp>
692  inline typename
693  __gnu_cxx::__enable_if<__is_byte<_Tp>::__value, void>::__type
694  __fill_a(_Tp* __first, _Tp* __last, const _Tp& __c)
695  {
696  const _Tp __tmp = __c;
697  __builtin_memset(__first, static_cast<unsigned char>(__tmp),
698  __last - __first);
699  }
700 
701  /**
702  * @brief Fills the range [first,last) with copies of value.
703  * @ingroup mutating_algorithms
704  * @param __first A forward iterator.
705  * @param __last A forward iterator.
706  * @param __value A reference-to-const of arbitrary type.
707  * @return Nothing.
708  *
709  * This function fills a range with copies of the same value. For char
710  * types filling contiguous areas of memory, this becomes an inline call
711  * to @c memset or @c wmemset.
712  */
713  template<typename _ForwardIterator, typename _Tp>
714  inline void
715  fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value)
716  {
717  // concept requirements
718  __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
719  _ForwardIterator>)
720  __glibcxx_requires_valid_range(__first, __last);
721 
722  std::__fill_a(std::__niter_base(__first), std::__niter_base(__last),
723  __value);
724  }
725 
726  template<typename _OutputIterator, typename _Size, typename _Tp>
727  inline typename
728  __gnu_cxx::__enable_if<!__is_scalar<_Tp>::__value, _OutputIterator>::__type
729  __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value)
730  {
731  for (__decltype(__n + 0) __niter = __n;
732  __niter > 0; --__niter, ++__first)
733  *__first = __value;
734  return __first;
735  }
736 
737  template<typename _OutputIterator, typename _Size, typename _Tp>
738  inline typename
739  __gnu_cxx::__enable_if<__is_scalar<_Tp>::__value, _OutputIterator>::__type
740  __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value)
741  {
742  const _Tp __tmp = __value;
743  for (__decltype(__n + 0) __niter = __n;
744  __niter > 0; --__niter, ++__first)
745  *__first = __tmp;
746  return __first;
747  }
748 
749  template<typename _Size, typename _Tp>
750  inline typename
751  __gnu_cxx::__enable_if<__is_byte<_Tp>::__value, _Tp*>::__type
752  __fill_n_a(_Tp* __first, _Size __n, const _Tp& __c)
753  {
754  std::__fill_a(__first, __first + __n, __c);
755  return __first + __n;
756  }
757 
758  /**
759  * @brief Fills the range [first,first+n) with copies of value.
760  * @ingroup mutating_algorithms
761  * @param __first An output iterator.
762  * @param __n The count of copies to perform.
763  * @param __value A reference-to-const of arbitrary type.
764  * @return The iterator at first+n.
765  *
766  * This function fills a range with copies of the same value. For char
767  * types filling contiguous areas of memory, this becomes an inline call
768  * to @c memset or @ wmemset.
769  *
770  * _GLIBCXX_RESOLVE_LIB_DEFECTS
771  * DR 865. More algorithms that throw away information
772  */
773  template<typename _OI, typename _Size, typename _Tp>
774  inline _OI
775  fill_n(_OI __first, _Size __n, const _Tp& __value)
776  {
777  // concept requirements
778  __glibcxx_function_requires(_OutputIteratorConcept<_OI, _Tp>)
779 
780  return _OI(std::__fill_n_a(std::__niter_base(__first), __n, __value));
781  }
782 
783  template<bool _BoolType>
784  struct __equal
785  {
786  template<typename _II1, typename _II2>
787  static bool
788  equal(_II1 __first1, _II1 __last1, _II2 __first2)
789  {
790  for (; __first1 != __last1; ++__first1, ++__first2)
791  if (!(*__first1 == *__first2))
792  return false;
793  return true;
794  }
795  };
796 
797  template<>
798  struct __equal<true>
799  {
800  template<typename _Tp>
801  static bool
802  equal(const _Tp* __first1, const _Tp* __last1, const _Tp* __first2)
803  {
804  return !__builtin_memcmp(__first1, __first2, sizeof(_Tp)
805  * (__last1 - __first1));
806  }
807  };
808 
809  template<typename _II1, typename _II2>
810  inline bool
811  __equal_aux(_II1 __first1, _II1 __last1, _II2 __first2)
812  {
813  typedef typename iterator_traits<_II1>::value_type _ValueType1;
814  typedef typename iterator_traits<_II2>::value_type _ValueType2;
815  const bool __simple = ((__is_integer<_ValueType1>::__value
816  || __is_pointer<_ValueType1>::__value)
817  && __is_pointer<_II1>::__value
818  && __is_pointer<_II2>::__value
819  && __are_same<_ValueType1, _ValueType2>::__value);
820 
821  return std::__equal<__simple>::equal(__first1, __last1, __first2);
822  }
823 
824 
825  template<typename, typename>
826  struct __lc_rai
827  {
828  template<typename _II1, typename _II2>
829  static _II1
830  __newlast1(_II1, _II1 __last1, _II2, _II2)
831  { return __last1; }
832 
833  template<typename _II>
834  static bool
835  __cnd2(_II __first, _II __last)
836  { return __first != __last; }
837  };
838 
839  template<>
840  struct __lc_rai<random_access_iterator_tag, random_access_iterator_tag>
841  {
842  template<typename _RAI1, typename _RAI2>
843  static _RAI1
844  __newlast1(_RAI1 __first1, _RAI1 __last1,
845  _RAI2 __first2, _RAI2 __last2)
846  {
847  const typename iterator_traits<_RAI1>::difference_type
848  __diff1 = __last1 - __first1;
849  const typename iterator_traits<_RAI2>::difference_type
850  __diff2 = __last2 - __first2;
851  return __diff2 < __diff1 ? __first1 + __diff2 : __last1;
852  }
853 
854  template<typename _RAI>
855  static bool
856  __cnd2(_RAI, _RAI)
857  { return true; }
858  };
859 
860  template<bool _BoolType>
861  struct __lexicographical_compare
862  {
863  template<typename _II1, typename _II2>
864  static bool __lc(_II1, _II1, _II2, _II2);
865  };
866 
867  template<bool _BoolType>
868  template<typename _II1, typename _II2>
869  bool
870  __lexicographical_compare<_BoolType>::
871  __lc(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
872  {
873  typedef typename iterator_traits<_II1>::iterator_category _Category1;
874  typedef typename iterator_traits<_II2>::iterator_category _Category2;
875  typedef std::__lc_rai<_Category1, _Category2> __rai_type;
876 
877  __last1 = __rai_type::__newlast1(__first1, __last1,
878  __first2, __last2);
879  for (; __first1 != __last1 && __rai_type::__cnd2(__first2, __last2);
880  ++__first1, ++__first2)
881  {
882  if (*__first1 < *__first2)
883  return true;
884  if (*__first2 < *__first1)
885  return false;
886  }
887  return __first1 == __last1 && __first2 != __last2;
888  }
889 
890  template<>
891  struct __lexicographical_compare<true>
892  {
893  template<typename _Tp, typename _Up>
894  static bool
895  __lc(const _Tp* __first1, const _Tp* __last1,
896  const _Up* __first2, const _Up* __last2)
897  {
898  const size_t __len1 = __last1 - __first1;
899  const size_t __len2 = __last2 - __first2;
900  const int __result = __builtin_memcmp(__first1, __first2,
901  std::min(__len1, __len2));
902  return __result != 0 ? __result < 0 : __len1 < __len2;
903  }
904  };
905 
906  template<typename _II1, typename _II2>
907  inline bool
908  __lexicographical_compare_aux(_II1 __first1, _II1 __last1,
909  _II2 __first2, _II2 __last2)
910  {
911  typedef typename iterator_traits<_II1>::value_type _ValueType1;
912  typedef typename iterator_traits<_II2>::value_type _ValueType2;
913  const bool __simple =
914  (__is_byte<_ValueType1>::__value && __is_byte<_ValueType2>::__value
915  && !__gnu_cxx::__numeric_traits<_ValueType1>::__is_signed
916  && !__gnu_cxx::__numeric_traits<_ValueType2>::__is_signed
917  && __is_pointer<_II1>::__value
918  && __is_pointer<_II2>::__value);
919 
920  return std::__lexicographical_compare<__simple>::__lc(__first1, __last1,
921  __first2, __last2);
922  }
923 
924  /**
925  * @brief Finds the first position in which @a val could be inserted
926  * without changing the ordering.
927  * @param __first An iterator.
928  * @param __last Another iterator.
929  * @param __val The search term.
930  * @return An iterator pointing to the first element <em>not less
931  * than</em> @a val, or end() if every element is less than
932  * @a val.
933  * @ingroup binary_search_algorithms
934  */
935  template<typename _ForwardIterator, typename _Tp>
936  _ForwardIterator
937  lower_bound(_ForwardIterator __first, _ForwardIterator __last,
938  const _Tp& __val)
939  {
940  typedef typename iterator_traits<_ForwardIterator>::value_type
941  _ValueType;
942  typedef typename iterator_traits<_ForwardIterator>::difference_type
943  _DistanceType;
944 
945  // concept requirements
946  __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
947  __glibcxx_function_requires(_LessThanOpConcept<_ValueType, _Tp>)
948  __glibcxx_requires_partitioned_lower(__first, __last, __val);
949 
950  _DistanceType __len = std::distance(__first, __last);
951 
952  while (__len > 0)
953  {
954  _DistanceType __half = __len >> 1;
955  _ForwardIterator __middle = __first;
956  std::advance(__middle, __half);
957  if (*__middle < __val)
958  {
959  __first = __middle;
960  ++__first;
961  __len = __len - __half - 1;
962  }
963  else
964  __len = __half;
965  }
966  return __first;
967  }
968 
969  /// This is a helper function for the sort routines and for random.tcc.
970  // Precondition: __n > 0.
971  template<typename _Size>
972  inline _Size
973  __lg(_Size __n)
974  {
975  _Size __k;
976  for (__k = 0; __n != 0; __n >>= 1)
977  ++__k;
978  return __k - 1;
979  }
980 
981  inline int
982  __lg(int __n)
983  { return sizeof(int) * __CHAR_BIT__ - 1 - __builtin_clz(__n); }
984 
985  inline unsigned
986  __lg(unsigned __n)
987  { return sizeof(int) * __CHAR_BIT__ - 1 - __builtin_clz(__n); }
988 
989  inline long
990  __lg(long __n)
991  { return sizeof(long) * __CHAR_BIT__ - 1 - __builtin_clzl(__n); }
992 
993  inline unsigned long
994  __lg(unsigned long __n)
995  { return sizeof(long) * __CHAR_BIT__ - 1 - __builtin_clzl(__n); }
996 
997  inline long long
998  __lg(long long __n)
999  { return sizeof(long long) * __CHAR_BIT__ - 1 - __builtin_clzll(__n); }
1000 
1001  inline unsigned long long
1002  __lg(unsigned long long __n)
1003  { return sizeof(long long) * __CHAR_BIT__ - 1 - __builtin_clzll(__n); }
1004 
1005 _GLIBCXX_END_NAMESPACE_VERSION
1006 
1007 _GLIBCXX_BEGIN_NAMESPACE_ALGO
1008 
1009  /**
1010  * @brief Tests a range for element-wise equality.
1011  * @ingroup non_mutating_algorithms
1012  * @param __first1 An input iterator.
1013  * @param __last1 An input iterator.
1014  * @param __first2 An input iterator.
1015  * @return A boolean true or false.
1016  *
1017  * This compares the elements of two ranges using @c == and returns true or
1018  * false depending on whether all of the corresponding elements of the
1019  * ranges are equal.
1020  */
1021  template<typename _II1, typename _II2>
1022  inline bool
1023  equal(_II1 __first1, _II1 __last1, _II2 __first2)
1024  {
1025  // concept requirements
1026  __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1027  __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1028  __glibcxx_function_requires(_EqualOpConcept<
1029  typename iterator_traits<_II1>::value_type,
1030  typename iterator_traits<_II2>::value_type>)
1031  __glibcxx_requires_valid_range(__first1, __last1);
1032 
1033  return std::__equal_aux(std::__niter_base(__first1),
1034  std::__niter_base(__last1),
1035  std::__niter_base(__first2));
1036  }
1037 
1038  /**
1039  * @brief Tests a range for element-wise equality.
1040  * @ingroup non_mutating_algorithms
1041  * @param __first1 An input iterator.
1042  * @param __last1 An input iterator.
1043  * @param __first2 An input iterator.
1044  * @param __binary_pred A binary predicate @link functors
1045  * functor@endlink.
1046  * @return A boolean true or false.
1047  *
1048  * This compares the elements of two ranges using the binary_pred
1049  * parameter, and returns true or
1050  * false depending on whether all of the corresponding elements of the
1051  * ranges are equal.
1052  */
1053  template<typename _IIter1, typename _IIter2, typename _BinaryPredicate>
1054  inline bool
1055  equal(_IIter1 __first1, _IIter1 __last1,
1056  _IIter2 __first2, _BinaryPredicate __binary_pred)
1057  {
1058  // concept requirements
1059  __glibcxx_function_requires(_InputIteratorConcept<_IIter1>)
1060  __glibcxx_function_requires(_InputIteratorConcept<_IIter2>)
1061  __glibcxx_requires_valid_range(__first1, __last1);
1062 
1063  for (; __first1 != __last1; ++__first1, ++__first2)
1064  if (!bool(__binary_pred(*__first1, *__first2)))
1065  return false;
1066  return true;
1067  }
1068 
1069  /**
1070  * @brief Performs @b dictionary comparison on ranges.
1071  * @ingroup sorting_algorithms
1072  * @param __first1 An input iterator.
1073  * @param __last1 An input iterator.
1074  * @param __first2 An input iterator.
1075  * @param __last2 An input iterator.
1076  * @return A boolean true or false.
1077  *
1078  * <em>Returns true if the sequence of elements defined by the range
1079  * [first1,last1) is lexicographically less than the sequence of elements
1080  * defined by the range [first2,last2). Returns false otherwise.</em>
1081  * (Quoted from [25.3.8]/1.) If the iterators are all character pointers,
1082  * then this is an inline call to @c memcmp.
1083  */
1084  template<typename _II1, typename _II2>
1085  inline bool
1086  lexicographical_compare(_II1 __first1, _II1 __last1,
1087  _II2 __first2, _II2 __last2)
1088  {
1089  // concept requirements
1090  typedef typename iterator_traits<_II1>::value_type _ValueType1;
1091  typedef typename iterator_traits<_II2>::value_type _ValueType2;
1092  __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1093  __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1094  __glibcxx_function_requires(_LessThanOpConcept<_ValueType1, _ValueType2>)
1095  __glibcxx_function_requires(_LessThanOpConcept<_ValueType2, _ValueType1>)
1096  __glibcxx_requires_valid_range(__first1, __last1);
1097  __glibcxx_requires_valid_range(__first2, __last2);
1098 
1099  return std::__lexicographical_compare_aux(std::__niter_base(__first1),
1100  std::__niter_base(__last1),
1101  std::__niter_base(__first2),
1102  std::__niter_base(__last2));
1103  }
1104 
1105  /**
1106  * @brief Performs @b dictionary comparison on ranges.
1107  * @ingroup sorting_algorithms
1108  * @param __first1 An input iterator.
1109  * @param __last1 An input iterator.
1110  * @param __first2 An input iterator.
1111  * @param __last2 An input iterator.
1112  * @param __comp A @link comparison_functors comparison functor@endlink.
1113  * @return A boolean true or false.
1114  *
1115  * The same as the four-parameter @c lexicographical_compare, but uses the
1116  * comp parameter instead of @c <.
1117  */
1118  template<typename _II1, typename _II2, typename _Compare>
1119  bool
1120  lexicographical_compare(_II1 __first1, _II1 __last1,
1121  _II2 __first2, _II2 __last2, _Compare __comp)
1122  {
1123  typedef typename iterator_traits<_II1>::iterator_category _Category1;
1124  typedef typename iterator_traits<_II2>::iterator_category _Category2;
1125  typedef std::__lc_rai<_Category1, _Category2> __rai_type;
1126 
1127  // concept requirements
1128  __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1129  __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1130  __glibcxx_requires_valid_range(__first1, __last1);
1131  __glibcxx_requires_valid_range(__first2, __last2);
1132 
1133  __last1 = __rai_type::__newlast1(__first1, __last1, __first2, __last2);
1134  for (; __first1 != __last1 && __rai_type::__cnd2(__first2, __last2);
1135  ++__first1, ++__first2)
1136  {
1137  if (__comp(*__first1, *__first2))
1138  return true;
1139  if (__comp(*__first2, *__first1))
1140  return false;
1141  }
1142  return __first1 == __last1 && __first2 != __last2;
1143  }
1144 
1145  /**
1146  * @brief Finds the places in ranges which don't match.
1147  * @ingroup non_mutating_algorithms
1148  * @param __first1 An input iterator.
1149  * @param __last1 An input iterator.
1150  * @param __first2 An input iterator.
1151  * @return A pair of iterators pointing to the first mismatch.
1152  *
1153  * This compares the elements of two ranges using @c == and returns a pair
1154  * of iterators. The first iterator points into the first range, the
1155  * second iterator points into the second range, and the elements pointed
1156  * to by the iterators are not equal.
1157  */
1158  template<typename _InputIterator1, typename _InputIterator2>
1159  pair<_InputIterator1, _InputIterator2>
1160  mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1161  _InputIterator2 __first2)
1162  {
1163  // concept requirements
1164  __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
1165  __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
1166  __glibcxx_function_requires(_EqualOpConcept<
1167  typename iterator_traits<_InputIterator1>::value_type,
1168  typename iterator_traits<_InputIterator2>::value_type>)
1169  __glibcxx_requires_valid_range(__first1, __last1);
1170 
1171  while (__first1 != __last1 && *__first1 == *__first2)
1172  {
1173  ++__first1;
1174  ++__first2;
1175  }
1176  return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
1177  }
1178 
1179  /**
1180  * @brief Finds the places in ranges which don't match.
1181  * @ingroup non_mutating_algorithms
1182  * @param __first1 An input iterator.
1183  * @param __last1 An input iterator.
1184  * @param __first2 An input iterator.
1185  * @param __binary_pred A binary predicate @link functors
1186  * functor@endlink.
1187  * @return A pair of iterators pointing to the first mismatch.
1188  *
1189  * This compares the elements of two ranges using the binary_pred
1190  * parameter, and returns a pair
1191  * of iterators. The first iterator points into the first range, the
1192  * second iterator points into the second range, and the elements pointed
1193  * to by the iterators are not equal.
1194  */
1195  template<typename _InputIterator1, typename _InputIterator2,
1196  typename _BinaryPredicate>
1197  pair<_InputIterator1, _InputIterator2>
1198  mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1199  _InputIterator2 __first2, _BinaryPredicate __binary_pred)
1200  {
1201  // concept requirements
1202  __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
1203  __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
1204  __glibcxx_requires_valid_range(__first1, __last1);
1205 
1206  while (__first1 != __last1 && bool(__binary_pred(*__first1, *__first2)))
1207  {
1208  ++__first1;
1209  ++__first2;
1210  }
1211  return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
1212  }
1213 
1214 _GLIBCXX_END_NAMESPACE_ALGO
1215 } // namespace std
1216 
1217 // NB: This file is included within many other C++ includes, as a way
1218 // of getting the base algorithms. So, make sure that parallel bits
1219 // come in too if requested.
1220 #ifdef _GLIBCXX_PARALLEL
1221 # include <parallel/algobase.h>
1222 #endif
1223 
1224 #endif