libstdc++-v3/include/bits/stl_algobase.h

   1 // Core algorithmic facilities -*- C++ -*-
   2
   3 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
   4 // 2011, 2012 Free Software Foundation, Inc.
   5 //
   6 // This file is part of the GNU ISO C++ Library.  This library is free
   7 // software; you can redistribute it and/or modify it under the
   8 // terms of the GNU General Public License as published by the
   9 // Free Software Foundation; either version 3, or (at your option)
  10 // any later version.
  11
  12 // This library is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 // GNU General Public License for more details.
  16
  17 // Under Section 7 of GPL version 3, you are granted additional
  18 // permissions described in the GCC Runtime Library Exception, version
  19 // 3.1, as published by the Free Software Foundation.
  20
  21 // You should have received a copy of the GNU General Public License and
  22 // a copy of the GCC Runtime Library Exception along with this program;
  23 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  24 // <http://www.gnu.org/licenses/>.
  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 #ifndef __GXX_EXPERIMENTAL_CXX0X__
  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 #ifndef __GXX_EXPERIMENTAL_CXX0X__
 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, ++__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     inline const _Tp&
 194     min(const _Tp& __a, const _Tp& __b)
 195     {
 196       // concept requirements
 197       __glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
 198
 199       return __b < __a ? __b : __a;
 200     }
 201
 202   /**
 203    *  @brief This does what you think it does.
 204    *  @ingroup sorting_algorithms
 205    *  @param  __a  A thing of arbitrary type.
 206    *  @param  __b  Another thing of arbitrary type.
 207    *  @return   The greater of the parameters.
 208    *
 209    *  This is the simple classic generic implementation.  It will work on
 210    *  temporary expressions, since they are only evaluated once, unlike a
 211    *  preprocessor macro.
 212   */
 213   template<typename _Tp>
 214     inline const _Tp&
 215     max(const _Tp& __a, const _Tp& __b)
 216     {
 217       // concept requirements
 218       __glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
 219
 220       return  __a < __b ? __b : __a;
 221     }
 222
 223   /**
 224    *  @brief This does what you think it does.
 225    *  @ingroup sorting_algorithms
 226    *  @param  __a  A thing of arbitrary type.
 227    *  @param  __b  Another thing of arbitrary type.
 228    *  @param  __comp  A @link comparison_functors comparison functor@endlink.
 229    *  @return   The lesser of the parameters.
 230    *
 231    *  This will work on temporary expressions, since they are only evaluated
 232    *  once, unlike a preprocessor macro.
 233   */
 234   template<typename _Tp, typename _Compare>
 235     inline const _Tp&
 236     min(const _Tp& __a, const _Tp& __b, _Compare __comp)
 237     { return __comp(__b, __a) ? __b : __a; }
 238
 239   /**
 240    *  @brief This does what you think it does.
 241    *  @ingroup sorting_algorithms
 242    *  @param  __a  A thing of arbitrary type.
 243    *  @param  __b  Another thing of arbitrary type.
 244    *  @param  __comp  A @link comparison_functors comparison functor@endlink.
 245    *  @return   The greater of the parameters.
 246    *
 247    *  This will work on temporary expressions, since they are only evaluated
 248    *  once, unlike a preprocessor macro.
 249   */
 250   template<typename _Tp, typename _Compare>
 251     inline const _Tp&
 252     max(const _Tp& __a, const _Tp& __b, _Compare __comp)
 253     { return __comp(__a, __b) ? __b : __a; }
 254
 255   // If _Iterator is a __normal_iterator return its base (a plain pointer,
 256   // normally) otherwise return it untouched.  See copy, fill, ...
 257   template<typename _Iterator>
 258     struct _Niter_base
 259     : _Iter_base<_Iterator, __is_normal_iterator<_Iterator>::__value>
 260     { };
 261
 262   template<typename _Iterator>
 263     inline typename _Niter_base<_Iterator>::iterator_type
 264     __niter_base(_Iterator __it)
 265     { return std::_Niter_base<_Iterator>::_S_base(__it); }
 266
 267   // Likewise, for move_iterator.
 268   template<typename _Iterator>
 269     struct _Miter_base
 270     : _Iter_base<_Iterator, __is_move_iterator<_Iterator>::__value>
 271     { };
 272
 273   template<typename _Iterator>
 274     inline typename _Miter_base<_Iterator>::iterator_type
 275     __miter_base(_Iterator __it)
 276     { return std::_Miter_base<_Iterator>::_S_base(__it); }
 277
 278   // All of these auxiliary structs serve two purposes.  (1) Replace
 279   // calls to copy with memmove whenever possible.  (Memmove, not memcpy,
 280   // because the input and output ranges are permitted to overlap.)
 281   // (2) If we're using random access iterators, then write the loop as
 282   // a for loop with an explicit count.
 283
 284   template<bool, bool, typename>
 285     struct __copy_move
 286     {
 287       template<typename _II, typename _OI>
 288         static _OI
 289         __copy_m(_II __first, _II __last, _OI __result)
 290         {
 291           for (; __first != __last; ++__result, ++__first)
 292             *__result = *__first;
 293           return __result;
 294         }
 295     };
 296
 297 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 298   template<typename _Category>
 299     struct __copy_move<true, false, _Category>
 300     {
 301       template<typename _II, typename _OI>
 302         static _OI
 303         __copy_m(_II __first, _II __last, _OI __result)
 304         {
 305           for (; __first != __last; ++__result, ++__first)
 306             *__result = std::move(*__first);
 307           return __result;
 308         }
 309     };
 310 #endif
 311
 312   template<>
 313     struct __copy_move<false, false, random_access_iterator_tag>
 314     {
 315       template<typename _II, typename _OI>
 316         static _OI
 317         __copy_m(_II __first, _II __last, _OI __result)
 318         {
 319           typedef typename iterator_traits<_II>::difference_type _Distance;
 320           for(_Distance __n = __last - __first; __n > 0; --__n)
 321             {
 322               *__result = *__first;
 323               ++__first;
 324               ++__result;
 325             }
 326           return __result;
 327         }
 328     };
 329
 330 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 331   template<>
 332     struct __copy_move<true, false, random_access_iterator_tag>
 333     {
 334       template<typename _II, typename _OI>
 335         static _OI
 336         __copy_m(_II __first, _II __last, _OI __result)
 337         {
 338           typedef typename iterator_traits<_II>::difference_type _Distance;
 339           for(_Distance __n = __last - __first; __n > 0; --__n)
 340             {
 341               *__result = std::move(*__first);
 342               ++__first;
 343               ++__result;
 344             }
 345           return __result;
 346         }
 347     };
 348 #endif
 349
 350   template<bool _IsMove>
 351     struct __copy_move<_IsMove, true, random_access_iterator_tag>
 352     {
 353       template<typename _Tp>
 354         static _Tp*
 355         __copy_m(const _Tp* __first, const _Tp* __last, _Tp* __result)
 356         {
 357           const ptrdiff_t _Num = __last - __first;
 358           if (_Num)
 359             __builtin_memmove(__result, __first, sizeof(_Tp) * _Num);
 360           return __result + _Num;
 361         }
 362     };
 363
 364   template<bool _IsMove, typename _II, typename _OI>
 365     inline _OI
 366     __copy_move_a(_II __first, _II __last, _OI __result)
 367     {
 368       typedef typename iterator_traits<_II>::value_type _ValueTypeI;
 369       typedef typename iterator_traits<_OI>::value_type _ValueTypeO;
 370       typedef typename iterator_traits<_II>::iterator_category _Category;
 371       const bool __simple = (__is_trivial(_ValueTypeI)
 372                              && __is_pointer<_II>::__value
 373                              && __is_pointer<_OI>::__value
 374                              && __are_same<_ValueTypeI, _ValueTypeO>::__value);
 375
 376       return std::__copy_move<_IsMove, __simple,
 377                               _Category>::__copy_m(__first, __last, __result);
 378     }
 379
 380   // Helpers for streambuf iterators (either istream or ostream).
 381   // NB: avoid including <iosfwd>, relatively large.
 382   template<typename _CharT>
 383     struct char_traits;
 384
 385   template<typename _CharT, typename _Traits>
 386     class istreambuf_iterator;
 387
 388   template<typename _CharT, typename _Traits>
 389     class ostreambuf_iterator;
 390
 391   template<bool _IsMove, typename _CharT>
 392     typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
 393              ostreambuf_iterator<_CharT, char_traits<_CharT> > >::__type
 394     __copy_move_a2(_CharT*, _CharT*,
 395                    ostreambuf_iterator<_CharT, char_traits<_CharT> >);
 396
 397   template<bool _IsMove, typename _CharT>
 398     typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
 399              ostreambuf_iterator<_CharT, char_traits<_CharT> > >::__type
 400     __copy_move_a2(const _CharT*, const _CharT*,
 401                    ostreambuf_iterator<_CharT, char_traits<_CharT> >);
 402
 403   template<bool _IsMove, typename _CharT>
 404     typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
 405                                     _CharT*>::__type
 406     __copy_move_a2(istreambuf_iterator<_CharT, char_traits<_CharT> >,
 407                    istreambuf_iterator<_CharT, char_traits<_CharT> >, _CharT*);
 408
 409   template<bool _IsMove, typename _II, typename _OI>
 410     inline _OI
 411     __copy_move_a2(_II __first, _II __last, _OI __result)
 412     {
 413       return _OI(std::__copy_move_a<_IsMove>(std::__niter_base(__first),
 414                                              std::__niter_base(__last),
 415                                              std::__niter_base(__result)));
 416     }
 417
 418   /**
 419    *  @brief Copies the range [first,last) into result.
 420    *  @ingroup mutating_algorithms
 421    *  @param  __first  An input iterator.
 422    *  @param  __last   An input iterator.
 423    *  @param  __result An output iterator.
 424    *  @return   result + (first - last)
 425    *
 426    *  This inline function will boil down to a call to @c memmove whenever
 427    *  possible.  Failing that, if random access iterators are passed, then the
 428    *  loop count will be known (and therefore a candidate for compiler
 429    *  optimizations such as unrolling).  Result may not be contained within
 430    *  [first,last); the copy_backward function should be used instead.
 431    *
 432    *  Note that the end of the output range is permitted to be contained
 433    *  within [first,last).
 434   */
 435   template<typename _II, typename _OI>
 436     inline _OI
 437     copy(_II __first, _II __last, _OI __result)
 438     {
 439       // concept requirements
 440       __glibcxx_function_requires(_InputIteratorConcept<_II>)
 441       __glibcxx_function_requires(_OutputIteratorConcept<_OI,
 442             typename iterator_traits<_II>::value_type>)
 443       __glibcxx_requires_valid_range(__first, __last);
 444
 445       return (std::__copy_move_a2<__is_move_iterator<_II>::__value>
 446               (std::__miter_base(__first), std::__miter_base(__last),
 447                __result));
 448     }
 449
 450 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 451   /**
 452    *  @brief Moves the range [first,last) into result.
 453    *  @ingroup mutating_algorithms
 454    *  @param  __first  An input iterator.
 455    *  @param  __last   An input iterator.
 456    *  @param  __result An output iterator.
 457    *  @return   result + (first - last)
 458    *
 459    *  This inline function will boil down to a call to @c memmove whenever
 460    *  possible.  Failing that, if random access iterators are passed, then the
 461    *  loop count will be known (and therefore a candidate for compiler
 462    *  optimizations such as unrolling).  Result may not be contained within
 463    *  [first,last); the move_backward function should be used instead.
 464    *
 465    *  Note that the end of the output range is permitted to be contained
 466    *  within [first,last).
 467   */
 468   template<typename _II, typename _OI>
 469     inline _OI
 470     move(_II __first, _II __last, _OI __result)
 471     {
 472       // concept requirements
 473       __glibcxx_function_requires(_InputIteratorConcept<_II>)
 474       __glibcxx_function_requires(_OutputIteratorConcept<_OI,
 475             typename iterator_traits<_II>::value_type>)
 476       __glibcxx_requires_valid_range(__first, __last);
 477
 478       return std::__copy_move_a2<true>(std::__miter_base(__first),
 479                                        std::__miter_base(__last), __result);
 480     }
 481
 482 #define _GLIBCXX_MOVE3(_Tp, _Up, _Vp) std::move(_Tp, _Up, _Vp)
 483 #else
 484 #define _GLIBCXX_MOVE3(_Tp, _Up, _Vp) std::copy(_Tp, _Up, _Vp)
 485 #endif
 486
 487   template<bool, bool, typename>
 488     struct __copy_move_backward
 489     {
 490       template<typename _BI1, typename _BI2>
 491         static _BI2
 492         __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
 493         {
 494           while (__first != __last)
 495             *--__result = *--__last;
 496           return __result;
 497         }
 498     };
 499
 500 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 501   template<typename _Category>
 502     struct __copy_move_backward<true, false, _Category>
 503     {
 504       template<typename _BI1, typename _BI2>
 505         static _BI2
 506         __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
 507         {
 508           while (__first != __last)
 509             *--__result = std::move(*--__last);
 510           return __result;
 511         }
 512     };
 513 #endif
 514
 515   template<>
 516     struct __copy_move_backward<false, false, random_access_iterator_tag>
 517     {
 518       template<typename _BI1, typename _BI2>
 519         static _BI2
 520         __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
 521         {
 522           typename iterator_traits<_BI1>::difference_type __n;
 523           for (__n = __last - __first; __n > 0; --__n)
 524             *--__result = *--__last;
 525           return __result;
 526         }
 527     };
 528
 529 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 530   template<>
 531     struct __copy_move_backward<true, false, random_access_iterator_tag>
 532     {
 533       template<typename _BI1, typename _BI2>
 534         static _BI2
 535         __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
 536         {
 537           typename iterator_traits<_BI1>::difference_type __n;
 538           for (__n = __last - __first; __n > 0; --__n)
 539             *--__result = std::move(*--__last);
 540           return __result;
 541         }
 542     };
 543 #endif
 544
 545   template<bool _IsMove>
 546     struct __copy_move_backward<_IsMove, true, random_access_iterator_tag>
 547     {
 548       template<typename _Tp>
 549         static _Tp*
 550         __copy_move_b(const _Tp* __first, const _Tp* __last, _Tp* __result)
 551         {
 552           const ptrdiff_t _Num = __last - __first;
 553           if (_Num)
 554             __builtin_memmove(__result - _Num, __first, sizeof(_Tp) * _Num);
 555           return __result - _Num;
 556         }
 557     };
 558
 559   template<bool _IsMove, typename _BI1, typename _BI2>
 560     inline _BI2
 561     __copy_move_backward_a(_BI1 __first, _BI1 __last, _BI2 __result)
 562     {
 563       typedef typename iterator_traits<_BI1>::value_type _ValueType1;
 564       typedef typename iterator_traits<_BI2>::value_type _ValueType2;
 565       typedef typename iterator_traits<_BI1>::iterator_category _Category;
 566       const bool __simple = (__is_trivial(_ValueType1)
 567                              && __is_pointer<_BI1>::__value
 568                              && __is_pointer<_BI2>::__value
 569                              && __are_same<_ValueType1, _ValueType2>::__value);
 570
 571       return std::__copy_move_backward<_IsMove, __simple,
 572                                        _Category>::__copy_move_b(__first,
 573                                                                  __last,
 574                                                                  __result);
 575     }
 576
 577   template<bool _IsMove, typename _BI1, typename _BI2>
 578     inline _BI2
 579     __copy_move_backward_a2(_BI1 __first, _BI1 __last, _BI2 __result)
 580     {
 581       return _BI2(std::__copy_move_backward_a<_IsMove>
 582                   (std::__niter_base(__first), std::__niter_base(__last),
 583                    std::__niter_base(__result)));
 584     }
 585
 586   /**
 587    *  @brief Copies the range [first,last) into result.
 588    *  @ingroup mutating_algorithms
 589    *  @param  __first  A bidirectional iterator.
 590    *  @param  __last   A bidirectional iterator.
 591    *  @param  __result A bidirectional iterator.
 592    *  @return   result - (first - last)
 593    *
 594    *  The function has the same effect as copy, but starts at the end of the
 595    *  range and works its way to the start, returning the start of the result.
 596    *  This inline function will boil down to a call to @c memmove whenever
 597    *  possible.  Failing that, if random access iterators are passed, then the
 598    *  loop count will be known (and therefore a candidate for compiler
 599    *  optimizations such as unrolling).
 600    *
 601    *  Result may not be in the range [first,last).  Use copy instead.  Note
 602    *  that the start of the output range may overlap [first,last).
 603   */
 604   template<typename _BI1, typename _BI2>
 605     inline _BI2
 606     copy_backward(_BI1 __first, _BI1 __last, _BI2 __result)
 607     {
 608       // concept requirements
 609       __glibcxx_function_requires(_BidirectionalIteratorConcept<_BI1>)
 610       __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<_BI2>)
 611       __glibcxx_function_requires(_ConvertibleConcept<
 612             typename iterator_traits<_BI1>::value_type,
 613             typename iterator_traits<_BI2>::value_type>)
 614       __glibcxx_requires_valid_range(__first, __last);
 615
 616       return (std::__copy_move_backward_a2<__is_move_iterator<_BI1>::__value>
 617               (std::__miter_base(__first), std::__miter_base(__last),
 618                __result));
 619     }
 620
 621 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 622   /**
 623    *  @brief Moves the range [first,last) into result.
 624    *  @ingroup mutating_algorithms
 625    *  @param  __first  A bidirectional iterator.
 626    *  @param  __last   A bidirectional iterator.
 627    *  @param  __result A bidirectional iterator.
 628    *  @return   result - (first - last)
 629    *
 630    *  The function has the same effect as move, but starts at the end of the
 631    *  range and works its way to the start, returning the start of the result.
 632    *  This inline function will boil down to a call to @c memmove whenever
 633    *  possible.  Failing that, if random access iterators are passed, then the
 634    *  loop count will be known (and therefore a candidate for compiler
 635    *  optimizations such as unrolling).
 636    *
 637    *  Result may not be in the range (first,last].  Use move instead.  Note
 638    *  that the start of the output range may overlap [first,last).
 639   */
 640   template<typename _BI1, typename _BI2>
 641     inline _BI2
 642     move_backward(_BI1 __first, _BI1 __last, _BI2 __result)
 643     {
 644       // concept requirements
 645       __glibcxx_function_requires(_BidirectionalIteratorConcept<_BI1>)
 646       __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<_BI2>)
 647       __glibcxx_function_requires(_ConvertibleConcept<
 648             typename iterator_traits<_BI1>::value_type,
 649             typename iterator_traits<_BI2>::value_type>)
 650       __glibcxx_requires_valid_range(__first, __last);
 651
 652       return std::__copy_move_backward_a2<true>(std::__miter_base(__first),
 653                                                 std::__miter_base(__last),
 654                                                 __result);
 655     }
 656
 657 #define _GLIBCXX_MOVE_BACKWARD3(_Tp, _Up, _Vp) std::move_backward(_Tp, _Up, _Vp)
 658 #else
 659 #define _GLIBCXX_MOVE_BACKWARD3(_Tp, _Up, _Vp) std::copy_backward(_Tp, _Up, _Vp)
 660 #endif
 661
 662   template<typename _ForwardIterator, typename _Tp>
 663     inline typename
 664     __gnu_cxx::__enable_if<!__is_scalar<_Tp>::__value, void>::__type
 665     __fill_a(_ForwardIterator __first, _ForwardIterator __last,
 666              const _Tp& __value)
 667     {
 668       for (; __first != __last; ++__first)
 669         *__first = __value;
 670     }
 671
 672   template<typename _ForwardIterator, typename _Tp>
 673     inline typename
 674     __gnu_cxx::__enable_if<__is_scalar<_Tp>::__value, void>::__type
 675     __fill_a(_ForwardIterator __first, _ForwardIterator __last,
 676              const _Tp& __value)
 677     {
 678       const _Tp __tmp = __value;
 679       for (; __first != __last; ++__first)
 680         *__first = __tmp;
 681     }
 682
 683   // Specialization: for char types we can use memset.
 684   template<typename _Tp>
 685     inline typename
 686     __gnu_cxx::__enable_if<__is_byte<_Tp>::__value, void>::__type
 687     __fill_a(_Tp* __first, _Tp* __last, const _Tp& __c)
 688     {
 689       const _Tp __tmp = __c;
 690       __builtin_memset(__first, static_cast<unsigned char>(__tmp),
 691                        __last - __first);
 692     }
 693
 694   /**
 695    *  @brief Fills the range [first,last) with copies of value.
 696    *  @ingroup mutating_algorithms
 697    *  @param  __first  A forward iterator.
 698    *  @param  __last   A forward iterator.
 699    *  @param  __value  A reference-to-const of arbitrary type.
 700    *  @return   Nothing.
 701    *
 702    *  This function fills a range with copies of the same value.  For char
 703    *  types filling contiguous areas of memory, this becomes an inline call
 704    *  to @c memset or @c wmemset.
 705   */
 706   template<typename _ForwardIterator, typename _Tp>
 707     inline void
 708     fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value)
 709     {
 710       // concept requirements
 711       __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
 712                                   _ForwardIterator>)
 713       __glibcxx_requires_valid_range(__first, __last);
 714
 715       std::__fill_a(std::__niter_base(__first), std::__niter_base(__last),
 716                     __value);
 717     }
 718
 719   template<typename _OutputIterator, typename _Size, typename _Tp>
 720     inline typename
 721     __gnu_cxx::__enable_if<!__is_scalar<_Tp>::__value, _OutputIterator>::__type
 722     __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value)
 723     {
 724       for (__decltype(__n + 0) __niter = __n;
 725            __niter > 0; --__niter, ++__first)
 726         *__first = __value;
 727       return __first;
 728     }
 729
 730   template<typename _OutputIterator, typename _Size, typename _Tp>
 731     inline typename
 732     __gnu_cxx::__enable_if<__is_scalar<_Tp>::__value, _OutputIterator>::__type
 733     __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value)
 734     {
 735       const _Tp __tmp = __value;
 736       for (__decltype(__n + 0) __niter = __n;
 737            __niter > 0; --__niter, ++__first)
 738         *__first = __tmp;
 739       return __first;
 740     }
 741
 742   template<typename _Size, typename _Tp>
 743     inline typename
 744     __gnu_cxx::__enable_if<__is_byte<_Tp>::__value, _Tp*>::__type
 745     __fill_n_a(_Tp* __first, _Size __n, const _Tp& __c)
 746     {
 747       std::__fill_a(__first, __first + __n, __c);
 748       return __first + __n;
 749     }
 750
 751   /**
 752    *  @brief Fills the range [first,first+n) with copies of value.
 753    *  @ingroup mutating_algorithms
 754    *  @param  __first  An output iterator.
 755    *  @param  __n      The count of copies to perform.
 756    *  @param  __value  A reference-to-const of arbitrary type.
 757    *  @return   The iterator at first+n.
 758    *
 759    *  This function fills a range with copies of the same value.  For char
 760    *  types filling contiguous areas of memory, this becomes an inline call
 761    *  to @c memset or @ wmemset.
 762    *
 763    *  _GLIBCXX_RESOLVE_LIB_DEFECTS
 764    *  DR 865. More algorithms that throw away information
 765   */
 766   template<typename _OI, typename _Size, typename _Tp>
 767     inline _OI
 768     fill_n(_OI __first, _Size __n, const _Tp& __value)
 769     {
 770       // concept requirements
 771       __glibcxx_function_requires(_OutputIteratorConcept<_OI, _Tp>)
 772
 773       return _OI(std::__fill_n_a(std::__niter_base(__first), __n, __value));
 774     }
 775
 776   template<bool _BoolType>
 777     struct __equal
 778     {
 779       template<typename _II1, typename _II2>
 780         static bool
 781         equal(_II1 __first1, _II1 __last1, _II2 __first2)
 782         {
 783           for (; __first1 != __last1; ++__first1, ++__first2)
 784             if (!(*__first1 == *__first2))
 785               return false;
 786           return true;
 787         }
 788     };
 789
 790   template<>
 791     struct __equal<true>
 792     {
 793       template<typename _Tp>
 794         static bool
 795         equal(const _Tp* __first1, const _Tp* __last1, const _Tp* __first2)
 796         {
 797           return !__builtin_memcmp(__first1, __first2, sizeof(_Tp)
 798                                    * (__last1 - __first1));
 799         }
 800     };
 801
 802   template<typename _II1, typename _II2>
 803     inline bool
 804     __equal_aux(_II1 __first1, _II1 __last1, _II2 __first2)
 805     {
 806       typedef typename iterator_traits<_II1>::value_type _ValueType1;
 807       typedef typename iterator_traits<_II2>::value_type _ValueType2;
 808       const bool __simple = ((__is_integer<_ValueType1>::__value
 809                               || __is_pointer<_ValueType1>::__value)
 810                              && __is_pointer<_II1>::__value
 811                              && __is_pointer<_II2>::__value
 812                              && __are_same<_ValueType1, _ValueType2>::__value);
 813
 814       return std::__equal<__simple>::equal(__first1, __last1, __first2);
 815     }
 816
 817
 818   template<typename, typename>
 819     struct __lc_rai
 820     {
 821       template<typename _II1, typename _II2>
 822         static _II1
 823         __newlast1(_II1, _II1 __last1, _II2, _II2)
 824         { return __last1; }
 825
 826       template<typename _II>
 827         static bool
 828         __cnd2(_II __first, _II __last)
 829         { return __first != __last; }
 830     };
 831
 832   template<>
 833     struct __lc_rai<random_access_iterator_tag, random_access_iterator_tag>
 834     {
 835       template<typename _RAI1, typename _RAI2>
 836         static _RAI1
 837         __newlast1(_RAI1 __first1, _RAI1 __last1,
 838                    _RAI2 __first2, _RAI2 __last2)
 839         {
 840           const typename iterator_traits<_RAI1>::difference_type
 841             __diff1 = __last1 - __first1;
 842           const typename iterator_traits<_RAI2>::difference_type
 843             __diff2 = __last2 - __first2;
 844           return __diff2 < __diff1 ? __first1 + __diff2 : __last1;
 845         }
 846
 847       template<typename _RAI>
 848         static bool
 849         __cnd2(_RAI, _RAI)
 850         { return true; }
 851     };
 852
 853   template<bool _BoolType>
 854     struct __lexicographical_compare
 855     {
 856       template<typename _II1, typename _II2>
 857         static bool __lc(_II1, _II1, _II2, _II2);
 858     };
 859
 860   template<bool _BoolType>
 861     template<typename _II1, typename _II2>
 862       bool
 863       __lexicographical_compare<_BoolType>::
 864       __lc(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
 865       {
 866         typedef typename iterator_traits<_II1>::iterator_category _Category1;
 867         typedef typename iterator_traits<_II2>::iterator_category _Category2;
 868         typedef std::__lc_rai<_Category1, _Category2>   __rai_type;
 869
 870         __last1 = __rai_type::__newlast1(__first1, __last1,
 871                                          __first2, __last2);
 872         for (; __first1 != __last1 && __rai_type::__cnd2(__first2, __last2);
 873              ++__first1, ++__first2)
 874           {
 875             if (*__first1 < *__first2)
 876               return true;
 877             if (*__first2 < *__first1)
 878               return false;
 879           }
 880         return __first1 == __last1 && __first2 != __last2;
 881       }
 882
 883   template<>
 884     struct __lexicographical_compare<true>
 885     {
 886       template<typename _Tp, typename _Up>
 887         static bool
 888         __lc(const _Tp* __first1, const _Tp* __last1,
 889              const _Up* __first2, const _Up* __last2)
 890         {
 891           const size_t __len1 = __last1 - __first1;
 892           const size_t __len2 = __last2 - __first2;
 893           const int __result = __builtin_memcmp(__first1, __first2,
 894                                                 std::min(__len1, __len2));
 895           return __result != 0 ? __result < 0 : __len1 < __len2;
 896         }
 897     };
 898
 899   template<typename _II1, typename _II2>
 900     inline bool
 901     __lexicographical_compare_aux(_II1 __first1, _II1 __last1,
 902                                   _II2 __first2, _II2 __last2)
 903     {
 904       typedef typename iterator_traits<_II1>::value_type _ValueType1;
 905       typedef typename iterator_traits<_II2>::value_type _ValueType2;
 906       const bool __simple =
 907         (__is_byte<_ValueType1>::__value && __is_byte<_ValueType2>::__value
 908          && !__gnu_cxx::__numeric_traits<_ValueType1>::__is_signed
 909          && !__gnu_cxx::__numeric_traits<_ValueType2>::__is_signed
 910          && __is_pointer<_II1>::__value
 911          && __is_pointer<_II2>::__value);
 912
 913       return std::__lexicographical_compare<__simple>::__lc(__first1, __last1,
 914                                                             __first2, __last2);
 915     }
 916
 917   /**
 918    *  @brief Finds the first position in which @a val could be inserted
 919    *         without changing the ordering.
 920    *  @param  __first   An iterator.
 921    *  @param  __last    Another iterator.
 922    *  @param  __val     The search term.
 923    *  @return         An iterator pointing to the first element <em>not less
 924    *                  than</em> @a val, or end() if every element is less than
 925    *                  @a val.
 926    *  @ingroup binary_search_algorithms
 927   */
 928   template<typename _ForwardIterator, typename _Tp>
 929     _ForwardIterator
 930     lower_bound(_ForwardIterator __first, _ForwardIterator __last,
 931                 const _Tp& __val)
 932     {
 933 #ifdef _GLIBCXX_CONCEPT_CHECKS
 934       typedef typename iterator_traits<_ForwardIterator>::value_type
 935         _ValueType;
 936 #endif
 937       typedef typename iterator_traits<_ForwardIterator>::difference_type
 938         _DistanceType;
 939
 940       // concept requirements
 941       __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
 942       __glibcxx_function_requires(_LessThanOpConcept<_ValueType, _Tp>)
 943       __glibcxx_requires_partitioned_lower(__first, __last, __val);
 944
 945       _DistanceType __len = std::distance(__first, __last);
 946
 947       while (__len > 0)
 948         {
 949           _DistanceType __half = __len >> 1;
 950           _ForwardIterator __middle = __first;
 951           std::advance(__middle, __half);
 952           if (*__middle < __val)
 953             {
 954               __first = __middle;
 955               ++__first;
 956               __len = __len - __half - 1;
 957             }
 958           else
 959             __len = __half;
 960         }
 961       return __first;
 962     }
 963
 964   /// This is a helper function for the sort routines and for random.tcc.
 965   //  Precondition: __n > 0.
 966   inline _GLIBCXX_CONSTEXPR int
 967   __lg(int __n)
 968   { return sizeof(int) * __CHAR_BIT__  - 1 - __builtin_clz(__n); }
 969
 970   inline _GLIBCXX_CONSTEXPR unsigned
 971   __lg(unsigned __n)
 972   { return sizeof(int) * __CHAR_BIT__  - 1 - __builtin_clz(__n); }
 973
 974   inline _GLIBCXX_CONSTEXPR long
 975   __lg(long __n)
 976   { return sizeof(long) * __CHAR_BIT__ - 1 - __builtin_clzl(__n); }
 977
 978   inline _GLIBCXX_CONSTEXPR unsigned long
 979   __lg(unsigned long __n)
 980   { return sizeof(long) * __CHAR_BIT__ - 1 - __builtin_clzl(__n); }
 981
 982   inline _GLIBCXX_CONSTEXPR long long
 983   __lg(long long __n)
 984   { return sizeof(long long) * __CHAR_BIT__ - 1 - __builtin_clzll(__n); }
 985
 986   inline _GLIBCXX_CONSTEXPR unsigned long long
 987   __lg(unsigned long long __n)
 988   { return sizeof(long long) * __CHAR_BIT__ - 1 - __builtin_clzll(__n); }
 989
 990 _GLIBCXX_END_NAMESPACE_VERSION
 991
 992 _GLIBCXX_BEGIN_NAMESPACE_ALGO
 993
 994   /**
 995    *  @brief Tests a range for element-wise equality.
 996    *  @ingroup non_mutating_algorithms
 997    *  @param  __first1  An input iterator.
 998    *  @param  __last1   An input iterator.
 999    *  @param  __first2  An input iterator.
1000    *  @return   A boolean true or false.
1001    *
1002    *  This compares the elements of two ranges using @c == and returns true or
1003    *  false depending on whether all of the corresponding elements of the
1004    *  ranges are equal.
1005   */
1006   template<typename _II1, typename _II2>
1007     inline bool
1008     equal(_II1 __first1, _II1 __last1, _II2 __first2)
1009     {
1010       // concept requirements
1011       __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1012       __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1013       __glibcxx_function_requires(_EqualOpConcept<
1014             typename iterator_traits<_II1>::value_type,
1015             typename iterator_traits<_II2>::value_type>)
1016       __glibcxx_requires_valid_range(__first1, __last1);
1017
1018       return std::__equal_aux(std::__niter_base(__first1),
1019                               std::__niter_base(__last1),
1020                               std::__niter_base(__first2));
1021     }
1022
1023   /**
1024    *  @brief Tests a range for element-wise equality.
1025    *  @ingroup non_mutating_algorithms
1026    *  @param  __first1  An input iterator.
1027    *  @param  __last1   An input iterator.
1028    *  @param  __first2  An input iterator.
1029    *  @param __binary_pred A binary predicate @link functors
1030    *                  functor@endlink.
1031    *  @return         A boolean true or false.
1032    *
1033    *  This compares the elements of two ranges using the binary_pred
1034    *  parameter, and returns true or
1035    *  false depending on whether all of the corresponding elements of the
1036    *  ranges are equal.
1037   */
1038   template<typename _IIter1, typename _IIter2, typename _BinaryPredicate>
1039     inline bool
1040     equal(_IIter1 __first1, _IIter1 __last1,
1041           _IIter2 __first2, _BinaryPredicate __binary_pred)
1042     {
1043       // concept requirements
1044       __glibcxx_function_requires(_InputIteratorConcept<_IIter1>)
1045       __glibcxx_function_requires(_InputIteratorConcept<_IIter2>)
1046       __glibcxx_requires_valid_range(__first1, __last1);
1047
1048       for (; __first1 != __last1; ++__first1, ++__first2)
1049         if (!bool(__binary_pred(*__first1, *__first2)))
1050           return false;
1051       return true;
1052     }
1053
1054   /**
1055    *  @brief Performs @b dictionary comparison on ranges.
1056    *  @ingroup sorting_algorithms
1057    *  @param  __first1  An input iterator.
1058    *  @param  __last1   An input iterator.
1059    *  @param  __first2  An input iterator.
1060    *  @param  __last2   An input iterator.
1061    *  @return   A boolean true or false.
1062    *
1063    *  <em>Returns true if the sequence of elements defined by the range
1064    *  [first1,last1) is lexicographically less than the sequence of elements
1065    *  defined by the range [first2,last2).  Returns false otherwise.</em>
1066    *  (Quoted from [25.3.8]/1.)  If the iterators are all character pointers,
1067    *  then this is an inline call to @c memcmp.
1068   */
1069   template<typename _II1, typename _II2>
1070     inline bool
1071     lexicographical_compare(_II1 __first1, _II1 __last1,
1072                             _II2 __first2, _II2 __last2)
1073     {
1074 #ifdef _GLIBCXX_CONCEPT_CHECKS
1075       // concept requirements
1076       typedef typename iterator_traits<_II1>::value_type _ValueType1;
1077       typedef typename iterator_traits<_II2>::value_type _ValueType2;
1078 #endif
1079       __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1080       __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1081       __glibcxx_function_requires(_LessThanOpConcept<_ValueType1, _ValueType2>)
1082       __glibcxx_function_requires(_LessThanOpConcept<_ValueType2, _ValueType1>)
1083       __glibcxx_requires_valid_range(__first1, __last1);
1084       __glibcxx_requires_valid_range(__first2, __last2);
1085
1086       return std::__lexicographical_compare_aux(std::__niter_base(__first1),
1087                                                 std::__niter_base(__last1),
1088                                                 std::__niter_base(__first2),
1089                                                 std::__niter_base(__last2));
1090     }
1091
1092   /**
1093    *  @brief Performs @b dictionary comparison on ranges.
1094    *  @ingroup sorting_algorithms
1095    *  @param  __first1  An input iterator.
1096    *  @param  __last1   An input iterator.
1097    *  @param  __first2  An input iterator.
1098    *  @param  __last2   An input iterator.
1099    *  @param  __comp  A @link comparison_functors comparison functor@endlink.
1100    *  @return   A boolean true or false.
1101    *
1102    *  The same as the four-parameter @c lexicographical_compare, but uses the
1103    *  comp parameter instead of @c <.
1104   */
1105   template<typename _II1, typename _II2, typename _Compare>
1106     bool
1107     lexicographical_compare(_II1 __first1, _II1 __last1,
1108                             _II2 __first2, _II2 __last2, _Compare __comp)
1109     {
1110       typedef typename iterator_traits<_II1>::iterator_category _Category1;
1111       typedef typename iterator_traits<_II2>::iterator_category _Category2;
1112       typedef std::__lc_rai<_Category1, _Category2>     __rai_type;
1113
1114       // concept requirements
1115       __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1116       __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1117       __glibcxx_requires_valid_range(__first1, __last1);
1118       __glibcxx_requires_valid_range(__first2, __last2);
1119
1120       __last1 = __rai_type::__newlast1(__first1, __last1, __first2, __last2);
1121       for (; __first1 != __last1 && __rai_type::__cnd2(__first2, __last2);
1122            ++__first1, ++__first2)
1123         {
1124           if (__comp(*__first1, *__first2))
1125             return true;
1126           if (__comp(*__first2, *__first1))
1127             return false;
1128         }
1129       return __first1 == __last1 && __first2 != __last2;
1130     }
1131
1132   /**
1133    *  @brief Finds the places in ranges which don't match.
1134    *  @ingroup non_mutating_algorithms
1135    *  @param  __first1  An input iterator.
1136    *  @param  __last1   An input iterator.
1137    *  @param  __first2  An input iterator.
1138    *  @return   A pair of iterators pointing to the first mismatch.
1139    *
1140    *  This compares the elements of two ranges using @c == and returns a pair
1141    *  of iterators.  The first iterator points into the first range, the
1142    *  second iterator points into the second range, and the elements pointed
1143    *  to by the iterators are not equal.
1144   */
1145   template<typename _InputIterator1, typename _InputIterator2>
1146     pair<_InputIterator1, _InputIterator2>
1147     mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1148              _InputIterator2 __first2)
1149     {
1150       // concept requirements
1151       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
1152       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
1153       __glibcxx_function_requires(_EqualOpConcept<
1154             typename iterator_traits<_InputIterator1>::value_type,
1155             typename iterator_traits<_InputIterator2>::value_type>)
1156       __glibcxx_requires_valid_range(__first1, __last1);
1157
1158       while (__first1 != __last1 && *__first1 == *__first2)
1159         {
1160           ++__first1;
1161           ++__first2;
1162         }
1163       return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
1164     }
1165
1166   /**
1167    *  @brief Finds the places in ranges which don't match.
1168    *  @ingroup non_mutating_algorithms
1169    *  @param  __first1  An input iterator.
1170    *  @param  __last1   An input iterator.
1171    *  @param  __first2  An input iterator.
1172    *  @param __binary_pred A binary predicate @link functors
1173    *         functor@endlink.
1174    *  @return   A pair of iterators pointing to the first mismatch.
1175    *
1176    *  This compares the elements of two ranges using the binary_pred
1177    *  parameter, and returns a pair
1178    *  of iterators.  The first iterator points into the first range, the
1179    *  second iterator points into the second range, and the elements pointed
1180    *  to by the iterators are not equal.
1181   */
1182   template<typename _InputIterator1, typename _InputIterator2,
1183            typename _BinaryPredicate>
1184     pair<_InputIterator1, _InputIterator2>
1185     mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1186              _InputIterator2 __first2, _BinaryPredicate __binary_pred)
1187     {
1188       // concept requirements
1189       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
1190       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
1191       __glibcxx_requires_valid_range(__first1, __last1);
1192
1193       while (__first1 != __last1 && bool(__binary_pred(*__first1, *__first2)))
1194         {
1195           ++__first1;
1196           ++__first2;
1197         }
1198       return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
1199     }
1200
1201 _GLIBCXX_END_NAMESPACE_ALGO
1202 } // namespace std
1203
1204 // NB: This file is included within many other C++ includes, as a way
1205 // of getting the base algorithms. So, make sure that parallel bits
1206 // come in too if requested.
1207 #ifdef _GLIBCXX_PARALLEL
1208 # include <parallel/algobase.h>
1209 #endif
1210
1211 #endif