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1// Core algorithmic facilities -*- C++ -*-
2
3// Copyright (C) 2001-2013 Free Software Foundation, Inc.
4//
5// This file is part of the GNU ISO C++ Library.  This library is free
6// software; you can redistribute it and/or modify it under the
7// terms of the GNU General Public License as published by the
8// Free Software Foundation; either version 3, or (at your option)
9// any later version.
10
11// This library is distributed in the hope that it will be useful,
12// but WITHOUT ANY WARRANTY; without even the implied warranty of
13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14// GNU General Public License for more details.
15
16// Under Section 7 of GPL version 3, you are granted additional
17// permissions described in the GCC Runtime Library Exception, version
18// 3.1, as published by the Free Software Foundation.
19
20// You should have received a copy of the GNU General Public License and
21// a copy of the GCC Runtime Library Exception along with this program;
22// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
23// <http://www.gnu.org/licenses/>.
24
25/*
26 *
27 * Copyright (c) 1994
28 * Hewlett-Packard Company
29 *
30 * Permission to use, copy, modify, distribute and sell this software
31 * and its documentation for any purpose is hereby granted without fee,
32 * provided that the above copyright notice appear in all copies and
33 * that both that copyright notice and this permission notice appear
34 * in supporting documentation.  Hewlett-Packard Company makes no
35 * representations about the suitability of this software for any
36 * purpose.  It is provided "as is" without express or implied warranty.
37 *
38 *
39 * Copyright (c) 1996-1998
40 * Silicon Graphics Computer Systems, Inc.
41 *
42 * Permission to use, copy, modify, distribute and sell this software
43 * and its documentation for any purpose is hereby granted without fee,
44 * provided that the above copyright notice appear in all copies and
45 * that both that copyright notice and this permission notice appear
46 * in supporting documentation.  Silicon Graphics makes no
47 * representations about the suitability of this software for any
48 * purpose.  It is provided "as is" without express or implied warranty.
49 */
50
51/** @file bits/stl_algobase.h
52 *  This is an internal header file, included by other library headers.
53 *  Do not attempt to use it directly. @headername{algorithm}
54 */
55
56#ifndef _STL_ALGOBASE_H
57#define _STL_ALGOBASE_H 1
58
59#include <bits/c++config.h>
60#include <bits/functexcept.h>
61#include <bits/cpp_type_traits.h>
62#include <ext/type_traits.h>
63#include <ext/numeric_traits.h>
64#include <bits/stl_pair.h>
65#include <bits/stl_iterator_base_types.h>
66#include <bits/stl_iterator_base_funcs.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
72namespace std _GLIBCXX_VISIBILITY(default)
73{
74_GLIBCXX_BEGIN_NAMESPACE_VERSION
75
76#if __cplusplus < 201103L
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#endif
106
107  /**
108   *  @brief Swaps the contents of two iterators.
109   *  @ingroup mutating_algorithms
110   *  @param  __a  An iterator.
111   *  @param  __b  Another iterator.
112   *  @return   Nothing.
113   *
114   *  This function swaps the values pointed to by two iterators, not the
115   *  iterators themselves.
116  */
117  template<typename _ForwardIterator1, typename _ForwardIterator2>
118    inline void
119    iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
120    {
121      // concept requirements
122      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
123				  _ForwardIterator1>)
124      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
125				  _ForwardIterator2>)
126
127#if __cplusplus < 201103L
128      typedef typename iterator_traits<_ForwardIterator1>::value_type
129	_ValueType1;
130      typedef typename iterator_traits<_ForwardIterator2>::value_type
131	_ValueType2;
132
133      __glibcxx_function_requires(_ConvertibleConcept<_ValueType1,
134				  _ValueType2>)
135      __glibcxx_function_requires(_ConvertibleConcept<_ValueType2,
136				  _ValueType1>)
137
138      typedef typename iterator_traits<_ForwardIterator1>::reference
139	_ReferenceType1;
140      typedef typename iterator_traits<_ForwardIterator2>::reference
141	_ReferenceType2;
142      std::__iter_swap<__are_same<_ValueType1, _ValueType2>::__value
143	&& __are_same<_ValueType1&, _ReferenceType1>::__value
144	&& __are_same<_ValueType2&, _ReferenceType2>::__value>::
145	iter_swap(__a, __b);
146#else
147      swap(*__a, *__b);
148#endif
149    }
150
151  /**
152   *  @brief Swap the elements of two sequences.
153   *  @ingroup mutating_algorithms
154   *  @param  __first1  A forward iterator.
155   *  @param  __last1   A forward iterator.
156   *  @param  __first2  A forward iterator.
157   *  @return   An iterator equal to @p first2+(last1-first1).
158   *
159   *  Swaps each element in the range @p [first1,last1) with the
160   *  corresponding element in the range @p [first2,(last1-first1)).
161   *  The ranges must not overlap.
162  */
163  template<typename _ForwardIterator1, typename _ForwardIterator2>
164    _ForwardIterator2
165    swap_ranges(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
166		_ForwardIterator2 __first2)
167    {
168      // concept requirements
169      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
170				  _ForwardIterator1>)
171      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
172				  _ForwardIterator2>)
173      __glibcxx_requires_valid_range(__first1, __last1);
174
175      for (; __first1 != __last1; ++__first1, ++__first2)
176	std::iter_swap(__first1, __first2);
177      return __first2;
178    }
179
180  /**
181   *  @brief This does what you think it does.
182   *  @ingroup sorting_algorithms
183   *  @param  __a  A thing of arbitrary type.
184   *  @param  __b  Another thing of arbitrary type.
185   *  @return   The lesser of the parameters.
186   *
187   *  This is the simple classic generic implementation.  It will work on
188   *  temporary expressions, since they are only evaluated once, unlike a
189   *  preprocessor macro.
190  */
191  template<typename _Tp>
192    inline const _Tp&
193    min(const _Tp& __a, const _Tp& __b)
194    {
195      // concept requirements
196      __glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
197      //return __b < __a ? __b : __a;
198      if (__b < __a)
199	return __b;
200      return __a;
201    }
202
203  /**
204   *  @brief This does what you think it does.
205   *  @ingroup sorting_algorithms
206   *  @param  __a  A thing of arbitrary type.
207   *  @param  __b  Another thing of arbitrary type.
208   *  @return   The greater of the parameters.
209   *
210   *  This is the simple classic generic implementation.  It will work on
211   *  temporary expressions, since they are only evaluated once, unlike a
212   *  preprocessor macro.
213  */
214  template<typename _Tp>
215    inline const _Tp&
216    max(const _Tp& __a, const _Tp& __b)
217    {
218      // concept requirements
219      __glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
220      //return  __a < __b ? __b : __a;
221      if (__a < __b)
222	return __b;
223      return __a;
224    }
225
226  /**
227   *  @brief This does what you think it does.
228   *  @ingroup sorting_algorithms
229   *  @param  __a  A thing of arbitrary type.
230   *  @param  __b  Another thing of arbitrary type.
231   *  @param  __comp  A @link comparison_functors comparison functor@endlink.
232   *  @return   The lesser of the parameters.
233   *
234   *  This will work on temporary expressions, since they are only evaluated
235   *  once, unlike a preprocessor macro.
236  */
237  template<typename _Tp, typename _Compare>
238    inline const _Tp&
239    min(const _Tp& __a, const _Tp& __b, _Compare __comp)
240    {
241      //return __comp(__b, __a) ? __b : __a;
242      if (__comp(__b, __a))
243	return __b;
244      return __a;
245    }
246
247  /**
248   *  @brief This does what you think it does.
249   *  @ingroup sorting_algorithms
250   *  @param  __a  A thing of arbitrary type.
251   *  @param  __b  Another thing of arbitrary type.
252   *  @param  __comp  A @link comparison_functors comparison functor@endlink.
253   *  @return   The greater of the parameters.
254   *
255   *  This will work on temporary expressions, since they are only evaluated
256   *  once, unlike a preprocessor macro.
257  */
258  template<typename _Tp, typename _Compare>
259    inline const _Tp&
260    max(const _Tp& __a, const _Tp& __b, _Compare __comp)
261    {
262      //return __comp(__a, __b) ? __b : __a;
263      if (__comp(__a, __b))
264	return __b;
265      return __a;
266    }
267
268  // If _Iterator is a __normal_iterator return its base (a plain pointer,
269  // normally) otherwise return it untouched.  See copy, fill, ...
270  template<typename _Iterator>
271    struct _Niter_base
272    : _Iter_base<_Iterator, __is_normal_iterator<_Iterator>::__value>
273    { };
274
275  template<typename _Iterator>
276    inline typename _Niter_base<_Iterator>::iterator_type
277    __niter_base(_Iterator __it)
278    { return std::_Niter_base<_Iterator>::_S_base(__it); }
279
280  // Likewise, for move_iterator.
281  template<typename _Iterator>
282    struct _Miter_base
283    : _Iter_base<_Iterator, __is_move_iterator<_Iterator>::__value>
284    { };
285
286  template<typename _Iterator>
287    inline typename _Miter_base<_Iterator>::iterator_type
288    __miter_base(_Iterator __it)
289    { return std::_Miter_base<_Iterator>::_S_base(__it); }
290
291  // All of these auxiliary structs serve two purposes.  (1) Replace
292  // calls to copy with memmove whenever possible.  (Memmove, not memcpy,
293  // because the input and output ranges are permitted to overlap.)
294  // (2) If we're using random access iterators, then write the loop as
295  // a for loop with an explicit count.
296
297  template<bool, bool, typename>
298    struct __copy_move
299    {
300      template<typename _II, typename _OI>
301        static _OI
302        __copy_m(_II __first, _II __last, _OI __result)
303        {
304	  for (; __first != __last; ++__result, ++__first)
305	    *__result = *__first;
306	  return __result;
307	}
308    };
309
310#if __cplusplus >= 201103L
311  template<typename _Category>
312    struct __copy_move<true, false, _Category>
313    {
314      template<typename _II, typename _OI>
315        static _OI
316        __copy_m(_II __first, _II __last, _OI __result)
317        {
318	  for (; __first != __last; ++__result, ++__first)
319	    *__result = std::move(*__first);
320	  return __result;
321	}
322    };
323#endif
324
325  template<>
326    struct __copy_move<false, false, random_access_iterator_tag>
327    {
328      template<typename _II, typename _OI>
329        static _OI
330        __copy_m(_II __first, _II __last, _OI __result)
331        {
332	  typedef typename iterator_traits<_II>::difference_type _Distance;
333	  for(_Distance __n = __last - __first; __n > 0; --__n)
334	    {
335	      *__result = *__first;
336	      ++__first;
337	      ++__result;
338	    }
339	  return __result;
340	}
341    };
342
343#if __cplusplus >= 201103L
344  template<>
345    struct __copy_move<true, false, random_access_iterator_tag>
346    {
347      template<typename _II, typename _OI>
348        static _OI
349        __copy_m(_II __first, _II __last, _OI __result)
350        {
351	  typedef typename iterator_traits<_II>::difference_type _Distance;
352	  for(_Distance __n = __last - __first; __n > 0; --__n)
353	    {
354	      *__result = std::move(*__first);
355	      ++__first;
356	      ++__result;
357	    }
358	  return __result;
359	}
360    };
361#endif
362
363  template<bool _IsMove>
364    struct __copy_move<_IsMove, true, random_access_iterator_tag>
365    {
366      template<typename _Tp>
367        static _Tp*
368        __copy_m(const _Tp* __first, const _Tp* __last, _Tp* __result)
369        {
370	  const ptrdiff_t _Num = __last - __first;
371	  if (_Num)
372	    __builtin_memmove(__result, __first, sizeof(_Tp) * _Num);
373	  return __result + _Num;
374	}
375    };
376
377  template<bool _IsMove, typename _II, typename _OI>
378    inline _OI
379    __copy_move_a(_II __first, _II __last, _OI __result)
380    {
381      typedef typename iterator_traits<_II>::value_type _ValueTypeI;
382      typedef typename iterator_traits<_OI>::value_type _ValueTypeO;
383      typedef typename iterator_traits<_II>::iterator_category _Category;
384      const bool __simple = (__is_trivial(_ValueTypeI)
385	                     && __is_pointer<_II>::__value
386	                     && __is_pointer<_OI>::__value
387			     && __are_same<_ValueTypeI, _ValueTypeO>::__value);
388
389      return std::__copy_move<_IsMove, __simple,
390	                      _Category>::__copy_m(__first, __last, __result);
391    }
392
393  // Helpers for streambuf iterators (either istream or ostream).
394  // NB: avoid including <iosfwd>, relatively large.
395  template<typename _CharT>
396    struct char_traits;
397
398  template<typename _CharT, typename _Traits>
399    class istreambuf_iterator;
400
401  template<typename _CharT, typename _Traits>
402    class ostreambuf_iterator;
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(_CharT*, _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	     ostreambuf_iterator<_CharT, char_traits<_CharT> > >::__type
413    __copy_move_a2(const _CharT*, const _CharT*,
414		   ostreambuf_iterator<_CharT, char_traits<_CharT> >);
415
416  template<bool _IsMove, typename _CharT>
417    typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
418				    _CharT*>::__type
419    __copy_move_a2(istreambuf_iterator<_CharT, char_traits<_CharT> >,
420		   istreambuf_iterator<_CharT, char_traits<_CharT> >, _CharT*);
421
422  template<bool _IsMove, typename _II, typename _OI>
423    inline _OI
424    __copy_move_a2(_II __first, _II __last, _OI __result)
425    {
426      return _OI(std::__copy_move_a<_IsMove>(std::__niter_base(__first),
427					     std::__niter_base(__last),
428					     std::__niter_base(__result)));
429    }
430
431  /**
432   *  @brief Copies the range [first,last) into result.
433   *  @ingroup mutating_algorithms
434   *  @param  __first  An input iterator.
435   *  @param  __last   An input iterator.
436   *  @param  __result An output iterator.
437   *  @return   result + (first - last)
438   *
439   *  This inline function will boil down to a call to @c memmove whenever
440   *  possible.  Failing that, if random access iterators are passed, then the
441   *  loop count will be known (and therefore a candidate for compiler
442   *  optimizations such as unrolling).  Result may not be contained within
443   *  [first,last); the copy_backward function should be used instead.
444   *
445   *  Note that the end of the output range is permitted to be contained
446   *  within [first,last).
447  */
448  template<typename _II, typename _OI>
449    inline _OI
450    copy(_II __first, _II __last, _OI __result)
451    {
452      // concept requirements
453      __glibcxx_function_requires(_InputIteratorConcept<_II>)
454      __glibcxx_function_requires(_OutputIteratorConcept<_OI,
455	    typename iterator_traits<_II>::value_type>)
456      __glibcxx_requires_valid_range(__first, __last);
457
458      return (std::__copy_move_a2<__is_move_iterator<_II>::__value>
459	      (std::__miter_base(__first), std::__miter_base(__last),
460	       __result));
461    }
462
463#if __cplusplus >= 201103L
464  /**
465   *  @brief Moves the range [first,last) into result.
466   *  @ingroup mutating_algorithms
467   *  @param  __first  An input iterator.
468   *  @param  __last   An input iterator.
469   *  @param  __result An output iterator.
470   *  @return   result + (first - last)
471   *
472   *  This inline function will boil down to a call to @c memmove whenever
473   *  possible.  Failing that, if random access iterators are passed, then the
474   *  loop count will be known (and therefore a candidate for compiler
475   *  optimizations such as unrolling).  Result may not be contained within
476   *  [first,last); the move_backward function should be used instead.
477   *
478   *  Note that the end of the output range is permitted to be contained
479   *  within [first,last).
480  */
481  template<typename _II, typename _OI>
482    inline _OI
483    move(_II __first, _II __last, _OI __result)
484    {
485      // concept requirements
486      __glibcxx_function_requires(_InputIteratorConcept<_II>)
487      __glibcxx_function_requires(_OutputIteratorConcept<_OI,
488	    typename iterator_traits<_II>::value_type>)
489      __glibcxx_requires_valid_range(__first, __last);
490
491      return std::__copy_move_a2<true>(std::__miter_base(__first),
492				       std::__miter_base(__last), __result);
493    }
494
495#define _GLIBCXX_MOVE3(_Tp, _Up, _Vp) std::move(_Tp, _Up, _Vp)
496#else
497#define _GLIBCXX_MOVE3(_Tp, _Up, _Vp) std::copy(_Tp, _Up, _Vp)
498#endif
499
500  template<bool, bool, typename>
501    struct __copy_move_backward
502    {
503      template<typename _BI1, typename _BI2>
504        static _BI2
505        __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
506        {
507	  while (__first != __last)
508	    *--__result = *--__last;
509	  return __result;
510	}
511    };
512
513#if __cplusplus >= 201103L
514  template<typename _Category>
515    struct __copy_move_backward<true, false, _Category>
516    {
517      template<typename _BI1, typename _BI2>
518        static _BI2
519        __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
520        {
521	  while (__first != __last)
522	    *--__result = std::move(*--__last);
523	  return __result;
524	}
525    };
526#endif
527
528  template<>
529    struct __copy_move_backward<false, false, random_access_iterator_tag>
530    {
531      template<typename _BI1, typename _BI2>
532        static _BI2
533        __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
534        {
535	  typename iterator_traits<_BI1>::difference_type __n;
536	  for (__n = __last - __first; __n > 0; --__n)
537	    *--__result = *--__last;
538	  return __result;
539	}
540    };
541
542#if __cplusplus >= 201103L
543  template<>
544    struct __copy_move_backward<true, false, random_access_iterator_tag>
545    {
546      template<typename _BI1, typename _BI2>
547        static _BI2
548        __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
549        {
550	  typename iterator_traits<_BI1>::difference_type __n;
551	  for (__n = __last - __first; __n > 0; --__n)
552	    *--__result = std::move(*--__last);
553	  return __result;
554	}
555    };
556#endif
557
558  template<bool _IsMove>
559    struct __copy_move_backward<_IsMove, true, random_access_iterator_tag>
560    {
561      template<typename _Tp>
562        static _Tp*
563        __copy_move_b(const _Tp* __first, const _Tp* __last, _Tp* __result)
564        {
565	  const ptrdiff_t _Num = __last - __first;
566	  if (_Num)
567	    __builtin_memmove(__result - _Num, __first, sizeof(_Tp) * _Num);
568	  return __result - _Num;
569	}
570    };
571
572  template<bool _IsMove, typename _BI1, typename _BI2>
573    inline _BI2
574    __copy_move_backward_a(_BI1 __first, _BI1 __last, _BI2 __result)
575    {
576      typedef typename iterator_traits<_BI1>::value_type _ValueType1;
577      typedef typename iterator_traits<_BI2>::value_type _ValueType2;
578      typedef typename iterator_traits<_BI1>::iterator_category _Category;
579      const bool __simple = (__is_trivial(_ValueType1)
580	                     && __is_pointer<_BI1>::__value
581	                     && __is_pointer<_BI2>::__value
582			     && __are_same<_ValueType1, _ValueType2>::__value);
583
584      return std::__copy_move_backward<_IsMove, __simple,
585	                               _Category>::__copy_move_b(__first,
586								 __last,
587								 __result);
588    }
589
590  template<bool _IsMove, typename _BI1, typename _BI2>
591    inline _BI2
592    __copy_move_backward_a2(_BI1 __first, _BI1 __last, _BI2 __result)
593    {
594      return _BI2(std::__copy_move_backward_a<_IsMove>
595		  (std::__niter_base(__first), std::__niter_base(__last),
596		   std::__niter_base(__result)));
597    }
598
599  /**
600   *  @brief Copies the range [first,last) into result.
601   *  @ingroup mutating_algorithms
602   *  @param  __first  A bidirectional iterator.
603   *  @param  __last   A bidirectional iterator.
604   *  @param  __result A bidirectional iterator.
605   *  @return   result - (first - last)
606   *
607   *  The function has the same effect as copy, but starts at the end of the
608   *  range and works its way to the start, returning the start of the result.
609   *  This inline function will boil down to a call to @c memmove whenever
610   *  possible.  Failing that, if random access iterators are passed, then the
611   *  loop count will be known (and therefore a candidate for compiler
612   *  optimizations such as unrolling).
613   *
614   *  Result may not be in the range [first,last).  Use copy instead.  Note
615   *  that the start of the output range may overlap [first,last).
616  */
617  template<typename _BI1, typename _BI2>
618    inline _BI2
619    copy_backward(_BI1 __first, _BI1 __last, _BI2 __result)
620    {
621      // concept requirements
622      __glibcxx_function_requires(_BidirectionalIteratorConcept<_BI1>)
623      __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<_BI2>)
624      __glibcxx_function_requires(_ConvertibleConcept<
625	    typename iterator_traits<_BI1>::value_type,
626	    typename iterator_traits<_BI2>::value_type>)
627      __glibcxx_requires_valid_range(__first, __last);
628
629      return (std::__copy_move_backward_a2<__is_move_iterator<_BI1>::__value>
630	      (std::__miter_base(__first), std::__miter_base(__last),
631	       __result));
632    }
633
634#if __cplusplus >= 201103L
635  /**
636   *  @brief Moves the range [first,last) into result.
637   *  @ingroup mutating_algorithms
638   *  @param  __first  A bidirectional iterator.
639   *  @param  __last   A bidirectional iterator.
640   *  @param  __result A bidirectional iterator.
641   *  @return   result - (first - last)
642   *
643   *  The function has the same effect as move, but starts at the end of the
644   *  range and works its way to the start, returning the start of the result.
645   *  This inline function will boil down to a call to @c memmove whenever
646   *  possible.  Failing that, if random access iterators are passed, then the
647   *  loop count will be known (and therefore a candidate for compiler
648   *  optimizations such as unrolling).
649   *
650   *  Result may not be in the range (first,last].  Use move instead.  Note
651   *  that the start of the output range may overlap [first,last).
652  */
653  template<typename _BI1, typename _BI2>
654    inline _BI2
655    move_backward(_BI1 __first, _BI1 __last, _BI2 __result)
656    {
657      // concept requirements
658      __glibcxx_function_requires(_BidirectionalIteratorConcept<_BI1>)
659      __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<_BI2>)
660      __glibcxx_function_requires(_ConvertibleConcept<
661	    typename iterator_traits<_BI1>::value_type,
662	    typename iterator_traits<_BI2>::value_type>)
663      __glibcxx_requires_valid_range(__first, __last);
664
665      return std::__copy_move_backward_a2<true>(std::__miter_base(__first),
666						std::__miter_base(__last),
667						__result);
668    }
669
670#define _GLIBCXX_MOVE_BACKWARD3(_Tp, _Up, _Vp) std::move_backward(_Tp, _Up, _Vp)
671#else
672#define _GLIBCXX_MOVE_BACKWARD3(_Tp, _Up, _Vp) std::copy_backward(_Tp, _Up, _Vp)
673#endif
674
675  template<typename _ForwardIterator, typename _Tp>
676    inline typename
677    __gnu_cxx::__enable_if<!__is_scalar<_Tp>::__value, void>::__type
678    __fill_a(_ForwardIterator __first, _ForwardIterator __last,
679 	     const _Tp& __value)
680    {
681      for (; __first != __last; ++__first)
682	*__first = __value;
683    }
684
685  template<typename _ForwardIterator, typename _Tp>
686    inline typename
687    __gnu_cxx::__enable_if<__is_scalar<_Tp>::__value, void>::__type
688    __fill_a(_ForwardIterator __first, _ForwardIterator __last,
689	     const _Tp& __value)
690    {
691      const _Tp __tmp = __value;
692      for (; __first != __last; ++__first)
693	*__first = __tmp;
694    }
695
696  // Specialization: for char types we can use memset.
697  template<typename _Tp>
698    inline typename
699    __gnu_cxx::__enable_if<__is_byte<_Tp>::__value, void>::__type
700    __fill_a(_Tp* __first, _Tp* __last, const _Tp& __c)
701    {
702      const _Tp __tmp = __c;
703      __builtin_memset(__first, static_cast<unsigned char>(__tmp),
704		       __last - __first);
705    }
706
707  /**
708   *  @brief Fills the range [first,last) with copies of value.
709   *  @ingroup mutating_algorithms
710   *  @param  __first  A forward iterator.
711   *  @param  __last   A forward iterator.
712   *  @param  __value  A reference-to-const of arbitrary type.
713   *  @return   Nothing.
714   *
715   *  This function fills a range with copies of the same value.  For char
716   *  types filling contiguous areas of memory, this becomes an inline call
717   *  to @c memset or @c wmemset.
718  */
719  template<typename _ForwardIterator, typename _Tp>
720    inline void
721    fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value)
722    {
723      // concept requirements
724      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
725				  _ForwardIterator>)
726      __glibcxx_requires_valid_range(__first, __last);
727
728      std::__fill_a(std::__niter_base(__first), std::__niter_base(__last),
729		    __value);
730    }
731
732  template<typename _OutputIterator, typename _Size, typename _Tp>
733    inline typename
734    __gnu_cxx::__enable_if<!__is_scalar<_Tp>::__value, _OutputIterator>::__type
735    __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value)
736    {
737      for (__decltype(__n + 0) __niter = __n;
738	   __niter > 0; --__niter, ++__first)
739	*__first = __value;
740      return __first;
741    }
742
743  template<typename _OutputIterator, typename _Size, typename _Tp>
744    inline typename
745    __gnu_cxx::__enable_if<__is_scalar<_Tp>::__value, _OutputIterator>::__type
746    __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value)
747    {
748      const _Tp __tmp = __value;
749      for (__decltype(__n + 0) __niter = __n;
750	   __niter > 0; --__niter, ++__first)
751	*__first = __tmp;
752      return __first;
753    }
754
755  template<typename _Size, typename _Tp>
756    inline typename
757    __gnu_cxx::__enable_if<__is_byte<_Tp>::__value, _Tp*>::__type
758    __fill_n_a(_Tp* __first, _Size __n, const _Tp& __c)
759    {
760      std::__fill_a(__first, __first + __n, __c);
761      return __first + __n;
762    }
763
764  /**
765   *  @brief Fills the range [first,first+n) with copies of value.
766   *  @ingroup mutating_algorithms
767   *  @param  __first  An output iterator.
768   *  @param  __n      The count of copies to perform.
769   *  @param  __value  A reference-to-const of arbitrary type.
770   *  @return   The iterator at first+n.
771   *
772   *  This function fills a range with copies of the same value.  For char
773   *  types filling contiguous areas of memory, this becomes an inline call
774   *  to @c memset or @ wmemset.
775   *
776   *  _GLIBCXX_RESOLVE_LIB_DEFECTS
777   *  DR 865. More algorithms that throw away information
778  */
779  template<typename _OI, typename _Size, typename _Tp>
780    inline _OI
781    fill_n(_OI __first, _Size __n, const _Tp& __value)
782    {
783      // concept requirements
784      __glibcxx_function_requires(_OutputIteratorConcept<_OI, _Tp>)
785
786      return _OI(std::__fill_n_a(std::__niter_base(__first), __n, __value));
787    }
788
789  template<bool _BoolType>
790    struct __equal
791    {
792      template<typename _II1, typename _II2>
793        static bool
794        equal(_II1 __first1, _II1 __last1, _II2 __first2)
795        {
796	  for (; __first1 != __last1; ++__first1, ++__first2)
797	    if (!(*__first1 == *__first2))
798	      return false;
799	  return true;
800	}
801    };
802
803  template<>
804    struct __equal<true>
805    {
806      template<typename _Tp>
807        static bool
808        equal(const _Tp* __first1, const _Tp* __last1, const _Tp* __first2)
809        {
810	  return !__builtin_memcmp(__first1, __first2, sizeof(_Tp)
811				   * (__last1 - __first1));
812	}
813    };
814
815  template<typename _II1, typename _II2>
816    inline bool
817    __equal_aux(_II1 __first1, _II1 __last1, _II2 __first2)
818    {
819      typedef typename iterator_traits<_II1>::value_type _ValueType1;
820      typedef typename iterator_traits<_II2>::value_type _ValueType2;
821      const bool __simple = ((__is_integer<_ValueType1>::__value
822			      || __is_pointer<_ValueType1>::__value)
823	                     && __is_pointer<_II1>::__value
824	                     && __is_pointer<_II2>::__value
825			     && __are_same<_ValueType1, _ValueType2>::__value);
826
827      return std::__equal<__simple>::equal(__first1, __last1, __first2);
828    }
829
830
831  template<typename, typename>
832    struct __lc_rai
833    {
834      template<typename _II1, typename _II2>
835        static _II1
836        __newlast1(_II1, _II1 __last1, _II2, _II2)
837        { return __last1; }
838
839      template<typename _II>
840        static bool
841        __cnd2(_II __first, _II __last)
842        { return __first != __last; }
843    };
844
845  template<>
846    struct __lc_rai<random_access_iterator_tag, random_access_iterator_tag>
847    {
848      template<typename _RAI1, typename _RAI2>
849        static _RAI1
850        __newlast1(_RAI1 __first1, _RAI1 __last1,
851		   _RAI2 __first2, _RAI2 __last2)
852        {
853	  const typename iterator_traits<_RAI1>::difference_type
854	    __diff1 = __last1 - __first1;
855	  const typename iterator_traits<_RAI2>::difference_type
856	    __diff2 = __last2 - __first2;
857	  return __diff2 < __diff1 ? __first1 + __diff2 : __last1;
858	}
859
860      template<typename _RAI>
861        static bool
862        __cnd2(_RAI, _RAI)
863        { return true; }
864    };
865
866  template<bool _BoolType>
867    struct __lexicographical_compare
868    {
869      template<typename _II1, typename _II2>
870        static bool __lc(_II1, _II1, _II2, _II2);
871    };
872
873  template<bool _BoolType>
874    template<typename _II1, typename _II2>
875      bool
876      __lexicographical_compare<_BoolType>::
877      __lc(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
878      {
879	typedef typename iterator_traits<_II1>::iterator_category _Category1;
880	typedef typename iterator_traits<_II2>::iterator_category _Category2;
881	typedef std::__lc_rai<_Category1, _Category2> 	__rai_type;
882
883	__last1 = __rai_type::__newlast1(__first1, __last1,
884					 __first2, __last2);
885	for (; __first1 != __last1 && __rai_type::__cnd2(__first2, __last2);
886	     ++__first1, ++__first2)
887	  {
888	    if (*__first1 < *__first2)
889	      return true;
890	    if (*__first2 < *__first1)
891	      return false;
892	  }
893	return __first1 == __last1 && __first2 != __last2;
894      }
895
896  template<>
897    struct __lexicographical_compare<true>
898    {
899      template<typename _Tp, typename _Up>
900        static bool
901        __lc(const _Tp* __first1, const _Tp* __last1,
902	     const _Up* __first2, const _Up* __last2)
903	{
904	  const size_t __len1 = __last1 - __first1;
905	  const size_t __len2 = __last2 - __first2;
906	  const int __result = __builtin_memcmp(__first1, __first2,
907						std::min(__len1, __len2));
908	  return __result != 0 ? __result < 0 : __len1 < __len2;
909	}
910    };
911
912  template<typename _II1, typename _II2>
913    inline bool
914    __lexicographical_compare_aux(_II1 __first1, _II1 __last1,
915				  _II2 __first2, _II2 __last2)
916    {
917      typedef typename iterator_traits<_II1>::value_type _ValueType1;
918      typedef typename iterator_traits<_II2>::value_type _ValueType2;
919      const bool __simple =
920	(__is_byte<_ValueType1>::__value && __is_byte<_ValueType2>::__value
921	 && !__gnu_cxx::__numeric_traits<_ValueType1>::__is_signed
922	 && !__gnu_cxx::__numeric_traits<_ValueType2>::__is_signed
923	 && __is_pointer<_II1>::__value
924	 && __is_pointer<_II2>::__value);
925
926      return std::__lexicographical_compare<__simple>::__lc(__first1, __last1,
927							    __first2, __last2);
928    }
929
930  /**
931   *  @brief Finds the first position in which @a val could be inserted
932   *         without changing the ordering.
933   *  @param  __first   An iterator.
934   *  @param  __last    Another iterator.
935   *  @param  __val     The search term.
936   *  @return         An iterator pointing to the first element <em>not less
937   *                  than</em> @a val, or end() if every element is less than
938   *                  @a val.
939   *  @ingroup binary_search_algorithms
940  */
941  template<typename _ForwardIterator, typename _Tp>
942    _ForwardIterator
943    lower_bound(_ForwardIterator __first, _ForwardIterator __last,
944		const _Tp& __val)
945    {
946#ifdef _GLIBCXX_CONCEPT_CHECKS
947      typedef typename iterator_traits<_ForwardIterator>::value_type
948	_ValueType;
949#endif
950      typedef typename iterator_traits<_ForwardIterator>::difference_type
951	_DistanceType;
952
953      // concept requirements
954      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
955      __glibcxx_function_requires(_LessThanOpConcept<_ValueType, _Tp>)
956      __glibcxx_requires_partitioned_lower(__first, __last, __val);
957
958      _DistanceType __len = std::distance(__first, __last);
959
960      while (__len > 0)
961	{
962	  _DistanceType __half = __len >> 1;
963	  _ForwardIterator __middle = __first;
964	  std::advance(__middle, __half);
965	  if (*__middle < __val)
966	    {
967	      __first = __middle;
968	      ++__first;
969	      __len = __len - __half - 1;
970	    }
971	  else
972	    __len = __half;
973	}
974      return __first;
975    }
976
977  /// This is a helper function for the sort routines and for random.tcc.
978  //  Precondition: __n > 0.
979  inline _GLIBCXX_CONSTEXPR int
980  __lg(int __n)
981  { return sizeof(int) * __CHAR_BIT__  - 1 - __builtin_clz(__n); }
982
983  inline _GLIBCXX_CONSTEXPR unsigned
984  __lg(unsigned __n)
985  { return sizeof(int) * __CHAR_BIT__  - 1 - __builtin_clz(__n); }
986
987  inline _GLIBCXX_CONSTEXPR long
988  __lg(long __n)
989  { return sizeof(long) * __CHAR_BIT__ - 1 - __builtin_clzl(__n); }
990
991  inline _GLIBCXX_CONSTEXPR unsigned long
992  __lg(unsigned long __n)
993  { return sizeof(long) * __CHAR_BIT__ - 1 - __builtin_clzl(__n); }
994
995  inline _GLIBCXX_CONSTEXPR long long
996  __lg(long long __n)
997  { return sizeof(long long) * __CHAR_BIT__ - 1 - __builtin_clzll(__n); }
998
999  inline _GLIBCXX_CONSTEXPR unsigned long long
1000  __lg(unsigned long long __n)
1001  { return sizeof(long long) * __CHAR_BIT__ - 1 - __builtin_clzll(__n); }
1002
1003_GLIBCXX_END_NAMESPACE_VERSION
1004
1005_GLIBCXX_BEGIN_NAMESPACE_ALGO
1006
1007  /**
1008   *  @brief Tests a range for element-wise equality.
1009   *  @ingroup non_mutating_algorithms
1010   *  @param  __first1  An input iterator.
1011   *  @param  __last1   An input iterator.
1012   *  @param  __first2  An input iterator.
1013   *  @return   A boolean true or false.
1014   *
1015   *  This compares the elements of two ranges using @c == and returns true or
1016   *  false depending on whether all of the corresponding elements of the
1017   *  ranges are equal.
1018  */
1019  template<typename _II1, typename _II2>
1020    inline bool
1021    equal(_II1 __first1, _II1 __last1, _II2 __first2)
1022    {
1023      // concept requirements
1024      __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1025      __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1026      __glibcxx_function_requires(_EqualOpConcept<
1027	    typename iterator_traits<_II1>::value_type,
1028	    typename iterator_traits<_II2>::value_type>)
1029      __glibcxx_requires_valid_range(__first1, __last1);
1030
1031      return std::__equal_aux(std::__niter_base(__first1),
1032			      std::__niter_base(__last1),
1033			      std::__niter_base(__first2));
1034    }
1035
1036  /**
1037   *  @brief Tests a range for element-wise equality.
1038   *  @ingroup non_mutating_algorithms
1039   *  @param  __first1  An input iterator.
1040   *  @param  __last1   An input iterator.
1041   *  @param  __first2  An input iterator.
1042   *  @param __binary_pred A binary predicate @link functors
1043   *                  functor@endlink.
1044   *  @return         A boolean true or false.
1045   *
1046   *  This compares the elements of two ranges using the binary_pred
1047   *  parameter, and returns true or
1048   *  false depending on whether all of the corresponding elements of the
1049   *  ranges are equal.
1050  */
1051  template<typename _IIter1, typename _IIter2, typename _BinaryPredicate>
1052    inline bool
1053    equal(_IIter1 __first1, _IIter1 __last1,
1054	  _IIter2 __first2, _BinaryPredicate __binary_pred)
1055    {
1056      // concept requirements
1057      __glibcxx_function_requires(_InputIteratorConcept<_IIter1>)
1058      __glibcxx_function_requires(_InputIteratorConcept<_IIter2>)
1059      __glibcxx_requires_valid_range(__first1, __last1);
1060
1061      for (; __first1 != __last1; ++__first1, ++__first2)
1062	if (!bool(__binary_pred(*__first1, *__first2)))
1063	  return false;
1064      return true;
1065    }
1066
1067  /**
1068   *  @brief Performs @b dictionary comparison on ranges.
1069   *  @ingroup sorting_algorithms
1070   *  @param  __first1  An input iterator.
1071   *  @param  __last1   An input iterator.
1072   *  @param  __first2  An input iterator.
1073   *  @param  __last2   An input iterator.
1074   *  @return   A boolean true or false.
1075   *
1076   *  <em>Returns true if the sequence of elements defined by the range
1077   *  [first1,last1) is lexicographically less than the sequence of elements
1078   *  defined by the range [first2,last2).  Returns false otherwise.</em>
1079   *  (Quoted from [25.3.8]/1.)  If the iterators are all character pointers,
1080   *  then this is an inline call to @c memcmp.
1081  */
1082  template<typename _II1, typename _II2>
1083    inline bool
1084    lexicographical_compare(_II1 __first1, _II1 __last1,
1085			    _II2 __first2, _II2 __last2)
1086    {
1087#ifdef _GLIBCXX_CONCEPT_CHECKS
1088      // concept requirements
1089      typedef typename iterator_traits<_II1>::value_type _ValueType1;
1090      typedef typename iterator_traits<_II2>::value_type _ValueType2;
1091#endif
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
1225