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

   1 // Core algorithmic facilities -*- C++ -*-
   2
   3 // Copyright (C) 2001-2015 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 #include <bits/predefined_ops.h>
  72
  73 namespace std _GLIBCXX_VISIBILITY(default)
  74 {
  75 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  76
  77 #if __cplusplus < 201103L
  78   // See http://gcc.gnu.org/ml/libstdc++/2004-08/msg00167.html: in a
  79   // nutshell, we are partially implementing the resolution of DR 187,
  80   // when it's safe, i.e., the value_types are equal.
  81   template<bool _BoolType>
  82     struct __iter_swap
  83     {
  84       template<typename _ForwardIterator1, typename _ForwardIterator2>
  85         static void
  86         iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
  87         {
  88           typedef typename iterator_traits<_ForwardIterator1>::value_type
  89             _ValueType1;
  90           _ValueType1 __tmp = _GLIBCXX_MOVE(*__a);
  91           *__a = _GLIBCXX_MOVE(*__b);
  92           *__b = _GLIBCXX_MOVE(__tmp);
  93         }
  94     };
  95
  96   template<>
  97     struct __iter_swap<true>
  98     {
  99       template<typename _ForwardIterator1, typename _ForwardIterator2>
 100         static void
 101         iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
 102         {
 103           swap(*__a, *__b);
 104         }
 105     };
 106 #endif
 107
 108   /**
 109    *  @brief Swaps the contents of two iterators.
 110    *  @ingroup mutating_algorithms
 111    *  @param  __a  An iterator.
 112    *  @param  __b  Another iterator.
 113    *  @return   Nothing.
 114    *
 115    *  This function swaps the values pointed to by two iterators, not the
 116    *  iterators themselves.
 117   */
 118   template<typename _ForwardIterator1, typename _ForwardIterator2>
 119     inline void
 120     iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
 121     {
 122       // concept requirements
 123       __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
 124                                   _ForwardIterator1>)
 125       __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
 126                                   _ForwardIterator2>)
 127
 128 #if __cplusplus < 201103L
 129       typedef typename iterator_traits<_ForwardIterator1>::value_type
 130         _ValueType1;
 131       typedef typename iterator_traits<_ForwardIterator2>::value_type
 132         _ValueType2;
 133
 134       __glibcxx_function_requires(_ConvertibleConcept<_ValueType1,
 135                                   _ValueType2>)
 136       __glibcxx_function_requires(_ConvertibleConcept<_ValueType2,
 137                                   _ValueType1>)
 138
 139       typedef typename iterator_traits<_ForwardIterator1>::reference
 140         _ReferenceType1;
 141       typedef typename iterator_traits<_ForwardIterator2>::reference
 142         _ReferenceType2;
 143       std::__iter_swap<__are_same<_ValueType1, _ValueType2>::__value
 144         && __are_same<_ValueType1&, _ReferenceType1>::__value
 145         && __are_same<_ValueType2&, _ReferenceType2>::__value>::
 146         iter_swap(__a, __b);
 147 #else
 148       swap(*__a, *__b);
 149 #endif
 150     }
 151
 152   /**
 153    *  @brief Swap the elements of two sequences.
 154    *  @ingroup mutating_algorithms
 155    *  @param  __first1  A forward iterator.
 156    *  @param  __last1   A forward iterator.
 157    *  @param  __first2  A forward iterator.
 158    *  @return   An iterator equal to @p first2+(last1-first1).
 159    *
 160    *  Swaps each element in the range @p [first1,last1) with the
 161    *  corresponding element in the range @p [first2,(last1-first1)).
 162    *  The ranges must not overlap.
 163   */
 164   template<typename _ForwardIterator1, typename _ForwardIterator2>
 165     _ForwardIterator2
 166     swap_ranges(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
 167                 _ForwardIterator2 __first2)
 168     {
 169       // concept requirements
 170       __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
 171                                   _ForwardIterator1>)
 172       __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
 173                                   _ForwardIterator2>)
 174       __glibcxx_requires_valid_range(__first1, __last1);
 175
 176       for (; __first1 != __last1; ++__first1, (void)++__first2)
 177         std::iter_swap(__first1, __first2);
 178       return __first2;
 179     }
 180
 181   /**
 182    *  @brief This does what you think it does.
 183    *  @ingroup sorting_algorithms
 184    *  @param  __a  A thing of arbitrary type.
 185    *  @param  __b  Another thing of arbitrary type.
 186    *  @return   The lesser of the parameters.
 187    *
 188    *  This is the simple classic generic implementation.  It will work on
 189    *  temporary expressions, since they are only evaluated once, unlike a
 190    *  preprocessor macro.
 191   */
 192   template<typename _Tp>
 193     _GLIBCXX14_CONSTEXPR
 194     inline const _Tp&
 195     min(const _Tp& __a, const _Tp& __b)
 196     {
 197       // concept requirements
 198       __glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
 199       //return __b < __a ? __b : __a;
 200       if (__b < __a)
 201         return __b;
 202       return __a;
 203     }
 204
 205   /**
 206    *  @brief This does what you think it does.
 207    *  @ingroup sorting_algorithms
 208    *  @param  __a  A thing of arbitrary type.
 209    *  @param  __b  Another thing of arbitrary type.
 210    *  @return   The greater of the parameters.
 211    *
 212    *  This is the simple classic generic implementation.  It will work on
 213    *  temporary expressions, since they are only evaluated once, unlike a
 214    *  preprocessor macro.
 215   */
 216   template<typename _Tp>
 217     _GLIBCXX14_CONSTEXPR
 218     inline const _Tp&
 219     max(const _Tp& __a, const _Tp& __b)
 220     {
 221       // concept requirements
 222       __glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
 223       //return  __a < __b ? __b : __a;
 224       if (__a < __b)
 225         return __b;
 226       return __a;
 227     }
 228
 229   /**
 230    *  @brief This does what you think it does.
 231    *  @ingroup sorting_algorithms
 232    *  @param  __a  A thing of arbitrary type.
 233    *  @param  __b  Another thing of arbitrary type.
 234    *  @param  __comp  A @link comparison_functors comparison functor@endlink.
 235    *  @return   The lesser of the parameters.
 236    *
 237    *  This will work on temporary expressions, since they are only evaluated
 238    *  once, unlike a preprocessor macro.
 239   */
 240   template<typename _Tp, typename _Compare>
 241     _GLIBCXX14_CONSTEXPR
 242     inline const _Tp&
 243     min(const _Tp& __a, const _Tp& __b, _Compare __comp)
 244     {
 245       //return __comp(__b, __a) ? __b : __a;
 246       if (__comp(__b, __a))
 247         return __b;
 248       return __a;
 249     }
 250
 251   /**
 252    *  @brief This does what you think it does.
 253    *  @ingroup sorting_algorithms
 254    *  @param  __a  A thing of arbitrary type.
 255    *  @param  __b  Another thing of arbitrary type.
 256    *  @param  __comp  A @link comparison_functors comparison functor@endlink.
 257    *  @return   The greater of the parameters.
 258    *
 259    *  This will work on temporary expressions, since they are only evaluated
 260    *  once, unlike a preprocessor macro.
 261   */
 262   template<typename _Tp, typename _Compare>
 263     _GLIBCXX14_CONSTEXPR
 264     inline const _Tp&
 265     max(const _Tp& __a, const _Tp& __b, _Compare __comp)
 266     {
 267       //return __comp(__a, __b) ? __b : __a;
 268       if (__comp(__a, __b))
 269         return __b;
 270       return __a;
 271     }
 272
 273   // Fallback implementation of the function in bits/stl_iterator.h used to
 274   // remove the __normal_iterator wrapper. See copy, fill, ...
 275   template<typename _Iterator>
 276     inline _Iterator
 277     __niter_base(_Iterator __it)
 278     { return __it; }
 279
 280   // All of these auxiliary structs serve two purposes.  (1) Replace
 281   // calls to copy with memmove whenever possible.  (Memmove, not memcpy,
 282   // because the input and output ranges are permitted to overlap.)
 283   // (2) If we're using random access iterators, then write the loop as
 284   // a for loop with an explicit count.
 285
 286   template<bool, bool, typename>
 287     struct __copy_move
 288     {
 289       template<typename _II, typename _OI>
 290         static _OI
 291         __copy_m(_II __first, _II __last, _OI __result)
 292         {
 293           for (; __first != __last; ++__result, (void)++__first)
 294             *__result = *__first;
 295           return __result;
 296         }
 297     };
 298
 299 #if __cplusplus >= 201103L
 300   template<typename _Category>
 301     struct __copy_move<true, false, _Category>
 302     {
 303       template<typename _II, typename _OI>
 304         static _OI
 305         __copy_m(_II __first, _II __last, _OI __result)
 306         {
 307           for (; __first != __last; ++__result, (void)++__first)
 308             *__result = std::move(*__first);
 309           return __result;
 310         }
 311     };
 312 #endif
 313
 314   template<>
 315     struct __copy_move<false, false, random_access_iterator_tag>
 316     {
 317       template<typename _II, typename _OI>
 318         static _OI
 319         __copy_m(_II __first, _II __last, _OI __result)
 320         {
 321           typedef typename iterator_traits<_II>::difference_type _Distance;
 322           for(_Distance __n = __last - __first; __n > 0; --__n)
 323             {
 324               *__result = *__first;
 325               ++__first;
 326               ++__result;
 327             }
 328           return __result;
 329         }
 330     };
 331
 332 #if __cplusplus >= 201103L
 333   template<>
 334     struct __copy_move<true, false, random_access_iterator_tag>
 335     {
 336       template<typename _II, typename _OI>
 337         static _OI
 338         __copy_m(_II __first, _II __last, _OI __result)
 339         {
 340           typedef typename iterator_traits<_II>::difference_type _Distance;
 341           for(_Distance __n = __last - __first; __n > 0; --__n)
 342             {
 343               *__result = std::move(*__first);
 344               ++__first;
 345               ++__result;
 346             }
 347           return __result;
 348         }
 349     };
 350 #endif
 351
 352   template<bool _IsMove>
 353     struct __copy_move<_IsMove, true, random_access_iterator_tag>
 354     {
 355       template<typename _Tp>
 356         static _Tp*
 357         __copy_m(const _Tp* __first, const _Tp* __last, _Tp* __result)
 358         {
 359 #if __cplusplus >= 201103L
 360           // trivial types can have deleted assignment
 361           static_assert( is_copy_assignable<_Tp>::value,
 362                          "type is not assignable" );
 363 #endif
 364           const ptrdiff_t _Num = __last - __first;
 365           if (_Num)
 366             __builtin_memmove(__result, __first, sizeof(_Tp) * _Num);
 367           return __result + _Num;
 368         }
 369     };
 370
 371   template<bool _IsMove, typename _II, typename _OI>
 372     inline _OI
 373     __copy_move_a(_II __first, _II __last, _OI __result)
 374     {
 375       typedef typename iterator_traits<_II>::value_type _ValueTypeI;
 376       typedef typename iterator_traits<_OI>::value_type _ValueTypeO;
 377       typedef typename iterator_traits<_II>::iterator_category _Category;
 378       const bool __simple = (__is_trivial(_ValueTypeI)
 379                              && __is_pointer<_II>::__value
 380                              && __is_pointer<_OI>::__value
 381                              && __are_same<_ValueTypeI, _ValueTypeO>::__value);
 382
 383       return std::__copy_move<_IsMove, __simple,
 384                               _Category>::__copy_m(__first, __last, __result);
 385     }
 386
 387   // Helpers for streambuf iterators (either istream or ostream).
 388   // NB: avoid including <iosfwd>, relatively large.
 389   template<typename _CharT>
 390     struct char_traits;
 391
 392   template<typename _CharT, typename _Traits>
 393     class istreambuf_iterator;
 394
 395   template<typename _CharT, typename _Traits>
 396     class ostreambuf_iterator;
 397
 398   template<bool _IsMove, typename _CharT>
 399     typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
 400              ostreambuf_iterator<_CharT, char_traits<_CharT> > >::__type
 401     __copy_move_a2(_CharT*, _CharT*,
 402                    ostreambuf_iterator<_CharT, char_traits<_CharT> >);
 403
 404   template<bool _IsMove, typename _CharT>
 405     typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
 406              ostreambuf_iterator<_CharT, char_traits<_CharT> > >::__type
 407     __copy_move_a2(const _CharT*, const _CharT*,
 408                    ostreambuf_iterator<_CharT, char_traits<_CharT> >);
 409
 410   template<bool _IsMove, typename _CharT>
 411     typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
 412                                     _CharT*>::__type
 413     __copy_move_a2(istreambuf_iterator<_CharT, char_traits<_CharT> >,
 414                    istreambuf_iterator<_CharT, char_traits<_CharT> >, _CharT*);
 415
 416   template<bool _IsMove, typename _II, typename _OI>
 417     inline _OI
 418     __copy_move_a2(_II __first, _II __last, _OI __result)
 419     {
 420       return _OI(std::__copy_move_a<_IsMove>(std::__niter_base(__first),
 421                                              std::__niter_base(__last),
 422                                              std::__niter_base(__result)));
 423     }
 424
 425   /**
 426    *  @brief Copies the range [first,last) into result.
 427    *  @ingroup mutating_algorithms
 428    *  @param  __first  An input iterator.
 429    *  @param  __last   An input iterator.
 430    *  @param  __result An output iterator.
 431    *  @return   result + (first - last)
 432    *
 433    *  This inline function will boil down to a call to @c memmove whenever
 434    *  possible.  Failing that, if random access iterators are passed, then the
 435    *  loop count will be known (and therefore a candidate for compiler
 436    *  optimizations such as unrolling).  Result may not be contained within
 437    *  [first,last); the copy_backward function should be used instead.
 438    *
 439    *  Note that the end of the output range is permitted to be contained
 440    *  within [first,last).
 441   */
 442   template<typename _II, typename _OI>
 443     inline _OI
 444     copy(_II __first, _II __last, _OI __result)
 445     {
 446       // concept requirements
 447       __glibcxx_function_requires(_InputIteratorConcept<_II>)
 448       __glibcxx_function_requires(_OutputIteratorConcept<_OI,
 449             typename iterator_traits<_II>::value_type>)
 450       __glibcxx_requires_valid_range(__first, __last);
 451
 452       return (std::__copy_move_a2<__is_move_iterator<_II>::__value>
 453               (std::__miter_base(__first), std::__miter_base(__last),
 454                __result));
 455     }
 456
 457 #if __cplusplus >= 201103L
 458   /**
 459    *  @brief Moves the range [first,last) into result.
 460    *  @ingroup mutating_algorithms
 461    *  @param  __first  An input iterator.
 462    *  @param  __last   An input iterator.
 463    *  @param  __result An output iterator.
 464    *  @return   result + (first - last)
 465    *
 466    *  This inline function will boil down to a call to @c memmove whenever
 467    *  possible.  Failing that, if random access iterators are passed, then the
 468    *  loop count will be known (and therefore a candidate for compiler
 469    *  optimizations such as unrolling).  Result may not be contained within
 470    *  [first,last); the move_backward function should be used instead.
 471    *
 472    *  Note that the end of the output range is permitted to be contained
 473    *  within [first,last).
 474   */
 475   template<typename _II, typename _OI>
 476     inline _OI
 477     move(_II __first, _II __last, _OI __result)
 478     {
 479       // concept requirements
 480       __glibcxx_function_requires(_InputIteratorConcept<_II>)
 481       __glibcxx_function_requires(_OutputIteratorConcept<_OI,
 482             typename iterator_traits<_II>::value_type>)
 483       __glibcxx_requires_valid_range(__first, __last);
 484
 485       return std::__copy_move_a2<true>(std::__miter_base(__first),
 486                                        std::__miter_base(__last), __result);
 487     }
 488
 489 #define _GLIBCXX_MOVE3(_Tp, _Up, _Vp) std::move(_Tp, _Up, _Vp)
 490 #else
 491 #define _GLIBCXX_MOVE3(_Tp, _Up, _Vp) std::copy(_Tp, _Up, _Vp)
 492 #endif
 493
 494   template<bool, bool, typename>
 495     struct __copy_move_backward
 496     {
 497       template<typename _BI1, typename _BI2>
 498         static _BI2
 499         __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
 500         {
 501           while (__first != __last)
 502             *--__result = *--__last;
 503           return __result;
 504         }
 505     };
 506
 507 #if __cplusplus >= 201103L
 508   template<typename _Category>
 509     struct __copy_move_backward<true, false, _Category>
 510     {
 511       template<typename _BI1, typename _BI2>
 512         static _BI2
 513         __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
 514         {
 515           while (__first != __last)
 516             *--__result = std::move(*--__last);
 517           return __result;
 518         }
 519     };
 520 #endif
 521
 522   template<>
 523     struct __copy_move_backward<false, false, random_access_iterator_tag>
 524     {
 525       template<typename _BI1, typename _BI2>
 526         static _BI2
 527         __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
 528         {
 529           typename iterator_traits<_BI1>::difference_type __n;
 530           for (__n = __last - __first; __n > 0; --__n)
 531             *--__result = *--__last;
 532           return __result;
 533         }
 534     };
 535
 536 #if __cplusplus >= 201103L
 537   template<>
 538     struct __copy_move_backward<true, false, random_access_iterator_tag>
 539     {
 540       template<typename _BI1, typename _BI2>
 541         static _BI2
 542         __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
 543         {
 544           typename iterator_traits<_BI1>::difference_type __n;
 545           for (__n = __last - __first; __n > 0; --__n)
 546             *--__result = std::move(*--__last);
 547           return __result;
 548         }
 549     };
 550 #endif
 551
 552   template<bool _IsMove>
 553     struct __copy_move_backward<_IsMove, true, random_access_iterator_tag>
 554     {
 555       template<typename _Tp>
 556         static _Tp*
 557         __copy_move_b(const _Tp* __first, const _Tp* __last, _Tp* __result)
 558         {
 559 #if __cplusplus >= 201103L
 560           // trivial types can have deleted assignment
 561           static_assert( is_copy_assignable<_Tp>::value,
 562                          "type is not assignable" );
 563 #endif
 564           const ptrdiff_t _Num = __last - __first;
 565           if (_Num)
 566             __builtin_memmove(__result - _Num, __first, sizeof(_Tp) * _Num);
 567           return __result - _Num;
 568         }
 569     };
 570
 571   template<bool _IsMove, typename _BI1, typename _BI2>
 572     inline _BI2
 573     __copy_move_backward_a(_BI1 __first, _BI1 __last, _BI2 __result)
 574     {
 575       typedef typename iterator_traits<_BI1>::value_type _ValueType1;
 576       typedef typename iterator_traits<_BI2>::value_type _ValueType2;
 577       typedef typename iterator_traits<_BI1>::iterator_category _Category;
 578       const bool __simple = (__is_trivial(_ValueType1)
 579                              && __is_pointer<_BI1>::__value
 580                              && __is_pointer<_BI2>::__value
 581                              && __are_same<_ValueType1, _ValueType2>::__value);
 582
 583       return std::__copy_move_backward<_IsMove, __simple,
 584                                        _Category>::__copy_move_b(__first,
 585                                                                  __last,
 586                                                                  __result);
 587     }
 588
 589   template<bool _IsMove, typename _BI1, typename _BI2>
 590     inline _BI2
 591     __copy_move_backward_a2(_BI1 __first, _BI1 __last, _BI2 __result)
 592     {
 593       return _BI2(std::__copy_move_backward_a<_IsMove>
 594                   (std::__niter_base(__first), std::__niter_base(__last),
 595                    std::__niter_base(__result)));
 596     }
 597
 598   /**
 599    *  @brief Copies the range [first,last) into result.
 600    *  @ingroup mutating_algorithms
 601    *  @param  __first  A bidirectional iterator.
 602    *  @param  __last   A bidirectional iterator.
 603    *  @param  __result A bidirectional iterator.
 604    *  @return   result - (first - last)
 605    *
 606    *  The function has the same effect as copy, but starts at the end of the
 607    *  range and works its way to the start, returning the start of the result.
 608    *  This inline function will boil down to a call to @c memmove whenever
 609    *  possible.  Failing that, if random access iterators are passed, then the
 610    *  loop count will be known (and therefore a candidate for compiler
 611    *  optimizations such as unrolling).
 612    *
 613    *  Result may not be in the range (first,last].  Use copy instead.  Note
 614    *  that the start of the output range may overlap [first,last).
 615   */
 616   template<typename _BI1, typename _BI2>
 617     inline _BI2
 618     copy_backward(_BI1 __first, _BI1 __last, _BI2 __result)
 619     {
 620       // concept requirements
 621       __glibcxx_function_requires(_BidirectionalIteratorConcept<_BI1>)
 622       __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<_BI2>)
 623       __glibcxx_function_requires(_ConvertibleConcept<
 624             typename iterator_traits<_BI1>::value_type,
 625             typename iterator_traits<_BI2>::value_type>)
 626       __glibcxx_requires_valid_range(__first, __last);
 627
 628       return (std::__copy_move_backward_a2<__is_move_iterator<_BI1>::__value>
 629               (std::__miter_base(__first), std::__miter_base(__last),
 630                __result));
 631     }
 632
 633 #if __cplusplus >= 201103L
 634   /**
 635    *  @brief Moves the range [first,last) into result.
 636    *  @ingroup mutating_algorithms
 637    *  @param  __first  A bidirectional iterator.
 638    *  @param  __last   A bidirectional iterator.
 639    *  @param  __result A bidirectional iterator.
 640    *  @return   result - (first - last)
 641    *
 642    *  The function has the same effect as move, but starts at the end of the
 643    *  range and works its way to the start, returning the start of the result.
 644    *  This inline function will boil down to a call to @c memmove whenever
 645    *  possible.  Failing that, if random access iterators are passed, then the
 646    *  loop count will be known (and therefore a candidate for compiler
 647    *  optimizations such as unrolling).
 648    *
 649    *  Result may not be in the range (first,last].  Use move instead.  Note
 650    *  that the start of the output range may overlap [first,last).
 651   */
 652   template<typename _BI1, typename _BI2>
 653     inline _BI2
 654     move_backward(_BI1 __first, _BI1 __last, _BI2 __result)
 655     {
 656       // concept requirements
 657       __glibcxx_function_requires(_BidirectionalIteratorConcept<_BI1>)
 658       __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<_BI2>)
 659       __glibcxx_function_requires(_ConvertibleConcept<
 660             typename iterator_traits<_BI1>::value_type,
 661             typename iterator_traits<_BI2>::value_type>)
 662       __glibcxx_requires_valid_range(__first, __last);
 663
 664       return std::__copy_move_backward_a2<true>(std::__miter_base(__first),
 665                                                 std::__miter_base(__last),
 666                                                 __result);
 667     }
 668
 669 #define _GLIBCXX_MOVE_BACKWARD3(_Tp, _Up, _Vp) std::move_backward(_Tp, _Up, _Vp)
 670 #else
 671 #define _GLIBCXX_MOVE_BACKWARD3(_Tp, _Up, _Vp) std::copy_backward(_Tp, _Up, _Vp)
 672 #endif
 673
 674   template<typename _ForwardIterator, typename _Tp>
 675     inline typename
 676     __gnu_cxx::__enable_if<!__is_scalar<_Tp>::__value, void>::__type
 677     __fill_a(_ForwardIterator __first, _ForwardIterator __last,
 678              const _Tp& __value)
 679     {
 680       for (; __first != __last; ++__first)
 681         *__first = __value;
 682     }
 683
 684   template<typename _ForwardIterator, typename _Tp>
 685     inline typename
 686     __gnu_cxx::__enable_if<__is_scalar<_Tp>::__value, void>::__type
 687     __fill_a(_ForwardIterator __first, _ForwardIterator __last,
 688              const _Tp& __value)
 689     {
 690       const _Tp __tmp = __value;
 691       for (; __first != __last; ++__first)
 692         *__first = __tmp;
 693     }
 694
 695   // Specialization: for char types we can use memset.
 696   template<typename _Tp>
 697     inline typename
 698     __gnu_cxx::__enable_if<__is_byte<_Tp>::__value, void>::__type
 699     __fill_a(_Tp* __first, _Tp* __last, const _Tp& __c)
 700     {
 701       const _Tp __tmp = __c;
 702       if (const size_t __len = __last - __first)
 703         __builtin_memset(__first, static_cast<unsigned char>(__tmp), __len);
 704     }
 705
 706   /**
 707    *  @brief Fills the range [first,last) with copies of value.
 708    *  @ingroup mutating_algorithms
 709    *  @param  __first  A forward iterator.
 710    *  @param  __last   A forward iterator.
 711    *  @param  __value  A reference-to-const of arbitrary type.
 712    *  @return   Nothing.
 713    *
 714    *  This function fills a range with copies of the same value.  For char
 715    *  types filling contiguous areas of memory, this becomes an inline call
 716    *  to @c memset or @c wmemset.
 717   */
 718   template<typename _ForwardIterator, typename _Tp>
 719     inline void
 720     fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value)
 721     {
 722       // concept requirements
 723       __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
 724                                   _ForwardIterator>)
 725       __glibcxx_requires_valid_range(__first, __last);
 726
 727       std::__fill_a(std::__niter_base(__first), std::__niter_base(__last),
 728                     __value);
 729     }
 730
 731   template<typename _OutputIterator, typename _Size, typename _Tp>
 732     inline typename
 733     __gnu_cxx::__enable_if<!__is_scalar<_Tp>::__value, _OutputIterator>::__type
 734     __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value)
 735     {
 736       for (__decltype(__n + 0) __niter = __n;
 737            __niter > 0; --__niter, ++__first)
 738         *__first = __value;
 739       return __first;
 740     }
 741
 742   template<typename _OutputIterator, typename _Size, typename _Tp>
 743     inline typename
 744     __gnu_cxx::__enable_if<__is_scalar<_Tp>::__value, _OutputIterator>::__type
 745     __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value)
 746     {
 747       const _Tp __tmp = __value;
 748       for (__decltype(__n + 0) __niter = __n;
 749            __niter > 0; --__niter, ++__first)
 750         *__first = __tmp;
 751       return __first;
 752     }
 753
 754   template<typename _Size, typename _Tp>
 755     inline typename
 756     __gnu_cxx::__enable_if<__is_byte<_Tp>::__value, _Tp*>::__type
 757     __fill_n_a(_Tp* __first, _Size __n, const _Tp& __c)
 758     {
 759       std::__fill_a(__first, __first + __n, __c);
 760       return __first + __n;
 761     }
 762
 763   /**
 764    *  @brief Fills the range [first,first+n) with copies of value.
 765    *  @ingroup mutating_algorithms
 766    *  @param  __first  An output iterator.
 767    *  @param  __n      The count of copies to perform.
 768    *  @param  __value  A reference-to-const of arbitrary type.
 769    *  @return   The iterator at first+n.
 770    *
 771    *  This function fills a range with copies of the same value.  For char
 772    *  types filling contiguous areas of memory, this becomes an inline call
 773    *  to @c memset or @ wmemset.
 774    *
 775    *  _GLIBCXX_RESOLVE_LIB_DEFECTS
 776    *  DR 865. More algorithms that throw away information
 777   */
 778   template<typename _OI, typename _Size, typename _Tp>
 779     inline _OI
 780     fill_n(_OI __first, _Size __n, const _Tp& __value)
 781     {
 782       // concept requirements
 783       __glibcxx_function_requires(_OutputIteratorConcept<_OI, _Tp>)
 784
 785       return _OI(std::__fill_n_a(std::__niter_base(__first), __n, __value));
 786     }
 787
 788   template<bool _BoolType>
 789     struct __equal
 790     {
 791       template<typename _II1, typename _II2>
 792         static bool
 793         equal(_II1 __first1, _II1 __last1, _II2 __first2)
 794         {
 795           for (; __first1 != __last1; ++__first1, (void)++__first2)
 796             if (!(*__first1 == *__first2))
 797               return false;
 798           return true;
 799         }
 800     };
 801
 802   template<>
 803     struct __equal<true>
 804     {
 805       template<typename _Tp>
 806         static bool
 807         equal(const _Tp* __first1, const _Tp* __last1, const _Tp* __first2)
 808         {
 809           if (const size_t __len = (__last1 - __first1))
 810             return !__builtin_memcmp(__first1, __first2, sizeof(_Tp) * __len);
 811           return true;
 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   template<typename, typename>
 831     struct __lc_rai
 832     {
 833       template<typename _II1, typename _II2>
 834         static _II1
 835         __newlast1(_II1, _II1 __last1, _II2, _II2)
 836         { return __last1; }
 837
 838       template<typename _II>
 839         static bool
 840         __cnd2(_II __first, _II __last)
 841         { return __first != __last; }
 842     };
 843
 844   template<>
 845     struct __lc_rai<random_access_iterator_tag, random_access_iterator_tag>
 846     {
 847       template<typename _RAI1, typename _RAI2>
 848         static _RAI1
 849         __newlast1(_RAI1 __first1, _RAI1 __last1,
 850                    _RAI2 __first2, _RAI2 __last2)
 851         {
 852           const typename iterator_traits<_RAI1>::difference_type
 853             __diff1 = __last1 - __first1;
 854           const typename iterator_traits<_RAI2>::difference_type
 855             __diff2 = __last2 - __first2;
 856           return __diff2 < __diff1 ? __first1 + __diff2 : __last1;
 857         }
 858
 859       template<typename _RAI>
 860         static bool
 861         __cnd2(_RAI, _RAI)
 862         { return true; }
 863     };
 864
 865   template<typename _II1, typename _II2, typename _Compare>
 866     bool
 867     __lexicographical_compare_impl(_II1 __first1, _II1 __last1,
 868                                    _II2 __first2, _II2 __last2,
 869                                    _Compare __comp)
 870     {
 871       typedef typename iterator_traits<_II1>::iterator_category _Category1;
 872       typedef typename iterator_traits<_II2>::iterator_category _Category2;
 873       typedef std::__lc_rai<_Category1, _Category2> __rai_type;
 874
 875       __last1 = __rai_type::__newlast1(__first1, __last1, __first2, __last2);
 876       for (; __first1 != __last1 && __rai_type::__cnd2(__first2, __last2);
 877            ++__first1, (void)++__first2)
 878         {
 879           if (__comp(__first1, __first2))
 880             return true;
 881           if (__comp(__first2, __first1))
 882             return false;
 883         }
 884       return __first1 == __last1 && __first2 != __last2;
 885     }
 886
 887   template<bool _BoolType>
 888     struct __lexicographical_compare
 889     {
 890       template<typename _II1, typename _II2>
 891         static bool __lc(_II1, _II1, _II2, _II2);
 892     };
 893
 894   template<bool _BoolType>
 895     template<typename _II1, typename _II2>
 896       bool
 897       __lexicographical_compare<_BoolType>::
 898       __lc(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
 899       {
 900         return std::__lexicographical_compare_impl(__first1, __last1,
 901                                                    __first2, __last2,
 902                                         __gnu_cxx::__ops::__iter_less_iter());
 903       }
 904
 905   template<>
 906     struct __lexicographical_compare<true>
 907     {
 908       template<typename _Tp, typename _Up>
 909         static bool
 910         __lc(const _Tp* __first1, const _Tp* __last1,
 911              const _Up* __first2, const _Up* __last2)
 912         {
 913           const size_t __len1 = __last1 - __first1;
 914           const size_t __len2 = __last2 - __first2;
 915           if (const size_t __len = std::min(__len1, __len2))
 916             if (int __result = __builtin_memcmp(__first1, __first2, __len))
 917               return __result < 0;
 918           return __len1 < __len2;
 919         }
 920     };
 921
 922   template<typename _II1, typename _II2>
 923     inline bool
 924     __lexicographical_compare_aux(_II1 __first1, _II1 __last1,
 925                                   _II2 __first2, _II2 __last2)
 926     {
 927       typedef typename iterator_traits<_II1>::value_type _ValueType1;
 928       typedef typename iterator_traits<_II2>::value_type _ValueType2;
 929       const bool __simple =
 930         (__is_byte<_ValueType1>::__value && __is_byte<_ValueType2>::__value
 931          && !__gnu_cxx::__numeric_traits<_ValueType1>::__is_signed
 932          && !__gnu_cxx::__numeric_traits<_ValueType2>::__is_signed
 933          && __is_pointer<_II1>::__value
 934          && __is_pointer<_II2>::__value);
 935
 936       return std::__lexicographical_compare<__simple>::__lc(__first1, __last1,
 937                                                             __first2, __last2);
 938     }
 939
 940   template<typename _ForwardIterator, typename _Tp, typename _Compare>
 941     _ForwardIterator
 942     __lower_bound(_ForwardIterator __first, _ForwardIterator __last,
 943                   const _Tp& __val, _Compare __comp)
 944     {
 945       typedef typename iterator_traits<_ForwardIterator>::difference_type
 946         _DistanceType;
 947
 948       _DistanceType __len = std::distance(__first, __last);
 949
 950       while (__len > 0)
 951         {
 952           _DistanceType __half = __len >> 1;
 953           _ForwardIterator __middle = __first;
 954           std::advance(__middle, __half);
 955           if (__comp(__middle, __val))
 956             {
 957               __first = __middle;
 958               ++__first;
 959               __len = __len - __half - 1;
 960             }
 961           else
 962             __len = __half;
 963         }
 964       return __first;
 965     }
 966
 967   /**
 968    *  @brief Finds the first position in which @a val could be inserted
 969    *         without changing the ordering.
 970    *  @param  __first   An iterator.
 971    *  @param  __last    Another iterator.
 972    *  @param  __val     The search term.
 973    *  @return         An iterator pointing to the first element <em>not less
 974    *                  than</em> @a val, or end() if every element is less than
 975    *                  @a val.
 976    *  @ingroup binary_search_algorithms
 977   */
 978   template<typename _ForwardIterator, typename _Tp>
 979     inline _ForwardIterator
 980     lower_bound(_ForwardIterator __first, _ForwardIterator __last,
 981                 const _Tp& __val)
 982     {
 983       // concept requirements
 984       __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
 985       __glibcxx_function_requires(_LessThanOpConcept<
 986             typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
 987       __glibcxx_requires_partitioned_lower(__first, __last, __val);
 988       __glibcxx_requires_irreflexive2(__first, __last);
 989
 990       return std::__lower_bound(__first, __last, __val,
 991                                 __gnu_cxx::__ops::__iter_less_val());
 992     }
 993
 994   /// This is a helper function for the sort routines and for random.tcc.
 995   //  Precondition: __n > 0.
 996   inline _GLIBCXX_CONSTEXPR int
 997   __lg(int __n)
 998   { return sizeof(int) * __CHAR_BIT__  - 1 - __builtin_clz(__n); }
 999
1000   inline _GLIBCXX_CONSTEXPR unsigned
1001   __lg(unsigned __n)
1002   { return sizeof(int) * __CHAR_BIT__  - 1 - __builtin_clz(__n); }
1003
1004   inline _GLIBCXX_CONSTEXPR long
1005   __lg(long __n)
1006   { return sizeof(long) * __CHAR_BIT__ - 1 - __builtin_clzl(__n); }
1007
1008   inline _GLIBCXX_CONSTEXPR unsigned long
1009   __lg(unsigned long __n)
1010   { return sizeof(long) * __CHAR_BIT__ - 1 - __builtin_clzl(__n); }
1011
1012   inline _GLIBCXX_CONSTEXPR long long
1013   __lg(long long __n)
1014   { return sizeof(long long) * __CHAR_BIT__ - 1 - __builtin_clzll(__n); }
1015
1016   inline _GLIBCXX_CONSTEXPR unsigned long long
1017   __lg(unsigned long long __n)
1018   { return sizeof(long long) * __CHAR_BIT__ - 1 - __builtin_clzll(__n); }
1019
1020 _GLIBCXX_END_NAMESPACE_VERSION
1021
1022 _GLIBCXX_BEGIN_NAMESPACE_ALGO
1023
1024   /**
1025    *  @brief Tests a range for element-wise equality.
1026    *  @ingroup non_mutating_algorithms
1027    *  @param  __first1  An input iterator.
1028    *  @param  __last1   An input iterator.
1029    *  @param  __first2  An input iterator.
1030    *  @return   A boolean true or false.
1031    *
1032    *  This compares the elements of two ranges using @c == and returns true or
1033    *  false depending on whether all of the corresponding elements of the
1034    *  ranges are equal.
1035   */
1036   template<typename _II1, typename _II2>
1037     inline bool
1038     equal(_II1 __first1, _II1 __last1, _II2 __first2)
1039     {
1040       // concept requirements
1041       __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1042       __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1043       __glibcxx_function_requires(_EqualOpConcept<
1044             typename iterator_traits<_II1>::value_type,
1045             typename iterator_traits<_II2>::value_type>)
1046       __glibcxx_requires_valid_range(__first1, __last1);
1047
1048       return std::__equal_aux(std::__niter_base(__first1),
1049                               std::__niter_base(__last1),
1050                               std::__niter_base(__first2));
1051     }
1052
1053   /**
1054    *  @brief Tests a range for element-wise equality.
1055    *  @ingroup non_mutating_algorithms
1056    *  @param  __first1  An input iterator.
1057    *  @param  __last1   An input iterator.
1058    *  @param  __first2  An input iterator.
1059    *  @param __binary_pred A binary predicate @link functors
1060    *                  functor@endlink.
1061    *  @return         A boolean true or false.
1062    *
1063    *  This compares the elements of two ranges using the binary_pred
1064    *  parameter, and returns true or
1065    *  false depending on whether all of the corresponding elements of the
1066    *  ranges are equal.
1067   */
1068   template<typename _IIter1, typename _IIter2, typename _BinaryPredicate>
1069     inline bool
1070     equal(_IIter1 __first1, _IIter1 __last1,
1071           _IIter2 __first2, _BinaryPredicate __binary_pred)
1072     {
1073       // concept requirements
1074       __glibcxx_function_requires(_InputIteratorConcept<_IIter1>)
1075       __glibcxx_function_requires(_InputIteratorConcept<_IIter2>)
1076       __glibcxx_requires_valid_range(__first1, __last1);
1077
1078       for (; __first1 != __last1; ++__first1, (void)++__first2)
1079         if (!bool(__binary_pred(*__first1, *__first2)))
1080           return false;
1081       return true;
1082     }
1083
1084 #if __cplusplus > 201103L
1085
1086 #define __cpp_lib_robust_nonmodifying_seq_ops 201304
1087
1088   /**
1089    *  @brief Tests a range for element-wise equality.
1090    *  @ingroup non_mutating_algorithms
1091    *  @param  __first1  An input iterator.
1092    *  @param  __last1   An input iterator.
1093    *  @param  __first2  An input iterator.
1094    *  @param  __last2   An input iterator.
1095    *  @return   A boolean true or false.
1096    *
1097    *  This compares the elements of two ranges using @c == and returns true or
1098    *  false depending on whether all of the corresponding elements of the
1099    *  ranges are equal.
1100   */
1101   template<typename _II1, typename _II2>
1102     inline bool
1103     equal(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
1104     {
1105       // concept requirements
1106       __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1107       __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1108       __glibcxx_function_requires(_EqualOpConcept<
1109             typename iterator_traits<_II1>::value_type,
1110             typename iterator_traits<_II2>::value_type>)
1111       __glibcxx_requires_valid_range(__first1, __last1);
1112       __glibcxx_requires_valid_range(__first2, __last2);
1113
1114       using _RATag = random_access_iterator_tag;
1115       using _Cat1 = typename iterator_traits<_II1>::iterator_category;
1116       using _Cat2 = typename iterator_traits<_II2>::iterator_category;
1117       using _RAIters = __and_<is_same<_Cat1, _RATag>, is_same<_Cat2, _RATag>>;
1118       if (_RAIters())
1119         {
1120           auto __d1 = std::distance(__first1, __last1);
1121           auto __d2 = std::distance(__first2, __last2);
1122           if (__d1 != __d2)
1123             return false;
1124           return _GLIBCXX_STD_A::equal(__first1, __last1, __first2);
1125         }
1126
1127       for (; __first1 != __last1 && __first2 != __last2;
1128           ++__first1, (void)++__first2)
1129         if (!(*__first1 == *__first2))
1130           return false;
1131       return __first1 == __last1 && __first2 == __last2;
1132     }
1133
1134   /**
1135    *  @brief Tests a range for element-wise equality.
1136    *  @ingroup non_mutating_algorithms
1137    *  @param  __first1  An input iterator.
1138    *  @param  __last1   An input iterator.
1139    *  @param  __first2  An input iterator.
1140    *  @param  __last2   An input iterator.
1141    *  @param __binary_pred A binary predicate @link functors
1142    *                  functor@endlink.
1143    *  @return         A boolean true or false.
1144    *
1145    *  This compares the elements of two ranges using the binary_pred
1146    *  parameter, and returns true or
1147    *  false depending on whether all of the corresponding elements of the
1148    *  ranges are equal.
1149   */
1150   template<typename _IIter1, typename _IIter2, typename _BinaryPredicate>
1151     inline bool
1152     equal(_IIter1 __first1, _IIter1 __last1,
1153           _IIter2 __first2, _IIter2 __last2, _BinaryPredicate __binary_pred)
1154     {
1155       // concept requirements
1156       __glibcxx_function_requires(_InputIteratorConcept<_IIter1>)
1157       __glibcxx_function_requires(_InputIteratorConcept<_IIter2>)
1158       __glibcxx_requires_valid_range(__first1, __last1);
1159       __glibcxx_requires_valid_range(__first2, __last2);
1160
1161       using _RATag = random_access_iterator_tag;
1162       using _Cat1 = typename iterator_traits<_IIter1>::iterator_category;
1163       using _Cat2 = typename iterator_traits<_IIter2>::iterator_category;
1164       using _RAIters = __and_<is_same<_Cat1, _RATag>, is_same<_Cat2, _RATag>>;
1165       if (_RAIters())
1166         {
1167           auto __d1 = std::distance(__first1, __last1);
1168           auto __d2 = std::distance(__first2, __last2);
1169           if (__d1 != __d2)
1170             return false;
1171           return _GLIBCXX_STD_A::equal(__first1, __last1, __first2,
1172                                        __binary_pred);
1173         }
1174
1175       for (; __first1 != __last1 && __first2 != __last2;
1176           ++__first1, (void)++__first2)
1177         if (!bool(__binary_pred(*__first1, *__first2)))
1178           return false;
1179       return __first1 == __last1 && __first2 == __last2;
1180     }
1181 #endif
1182
1183   /**
1184    *  @brief Performs @b dictionary comparison on ranges.
1185    *  @ingroup sorting_algorithms
1186    *  @param  __first1  An input iterator.
1187    *  @param  __last1   An input iterator.
1188    *  @param  __first2  An input iterator.
1189    *  @param  __last2   An input iterator.
1190    *  @return   A boolean true or false.
1191    *
1192    *  <em>Returns true if the sequence of elements defined by the range
1193    *  [first1,last1) is lexicographically less than the sequence of elements
1194    *  defined by the range [first2,last2).  Returns false otherwise.</em>
1195    *  (Quoted from [25.3.8]/1.)  If the iterators are all character pointers,
1196    *  then this is an inline call to @c memcmp.
1197   */
1198   template<typename _II1, typename _II2>
1199     inline bool
1200     lexicographical_compare(_II1 __first1, _II1 __last1,
1201                             _II2 __first2, _II2 __last2)
1202     {
1203 #ifdef _GLIBCXX_CONCEPT_CHECKS
1204       // concept requirements
1205       typedef typename iterator_traits<_II1>::value_type _ValueType1;
1206       typedef typename iterator_traits<_II2>::value_type _ValueType2;
1207 #endif
1208       __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1209       __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1210       __glibcxx_function_requires(_LessThanOpConcept<_ValueType1, _ValueType2>)
1211       __glibcxx_function_requires(_LessThanOpConcept<_ValueType2, _ValueType1>)
1212       __glibcxx_requires_valid_range(__first1, __last1);
1213       __glibcxx_requires_irreflexive2(__first1, __last1);
1214       __glibcxx_requires_valid_range(__first2, __last2);
1215       __glibcxx_requires_irreflexive2(__first2, __last2);
1216
1217       return std::__lexicographical_compare_aux(std::__niter_base(__first1),
1218                                                 std::__niter_base(__last1),
1219                                                 std::__niter_base(__first2),
1220                                                 std::__niter_base(__last2));
1221     }
1222
1223   /**
1224    *  @brief Performs @b dictionary comparison on ranges.
1225    *  @ingroup sorting_algorithms
1226    *  @param  __first1  An input iterator.
1227    *  @param  __last1   An input iterator.
1228    *  @param  __first2  An input iterator.
1229    *  @param  __last2   An input iterator.
1230    *  @param  __comp  A @link comparison_functors comparison functor@endlink.
1231    *  @return   A boolean true or false.
1232    *
1233    *  The same as the four-parameter @c lexicographical_compare, but uses the
1234    *  comp parameter instead of @c <.
1235   */
1236   template<typename _II1, typename _II2, typename _Compare>
1237     inline bool
1238     lexicographical_compare(_II1 __first1, _II1 __last1,
1239                             _II2 __first2, _II2 __last2, _Compare __comp)
1240     {
1241       // concept requirements
1242       __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1243       __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1244       __glibcxx_requires_valid_range(__first1, __last1);
1245       __glibcxx_requires_irreflexive_pred2(__first1, __last1, __comp);
1246       __glibcxx_requires_valid_range(__first2, __last2);
1247       __glibcxx_requires_irreflexive_pred2(__first2, __last2, __comp);
1248
1249       return std::__lexicographical_compare_impl
1250         (__first1, __last1, __first2, __last2,
1251          __gnu_cxx::__ops::__iter_comp_iter(__comp));
1252     }
1253
1254   template<typename _InputIterator1, typename _InputIterator2,
1255            typename _BinaryPredicate>
1256     pair<_InputIterator1, _InputIterator2>
1257     __mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1258                _InputIterator2 __first2, _BinaryPredicate __binary_pred)
1259     {
1260       while (__first1 != __last1 && __binary_pred(__first1, __first2))
1261         {
1262           ++__first1;
1263           ++__first2;
1264         }
1265       return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
1266     }
1267
1268   /**
1269    *  @brief Finds the places in ranges which don't match.
1270    *  @ingroup non_mutating_algorithms
1271    *  @param  __first1  An input iterator.
1272    *  @param  __last1   An input iterator.
1273    *  @param  __first2  An input iterator.
1274    *  @return   A pair of iterators pointing to the first mismatch.
1275    *
1276    *  This compares the elements of two ranges using @c == and returns a pair
1277    *  of iterators.  The first iterator points into the first range, the
1278    *  second iterator points into the second range, and the elements pointed
1279    *  to by the iterators are not equal.
1280   */
1281   template<typename _InputIterator1, typename _InputIterator2>
1282     inline pair<_InputIterator1, _InputIterator2>
1283     mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1284              _InputIterator2 __first2)
1285     {
1286       // concept requirements
1287       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
1288       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
1289       __glibcxx_function_requires(_EqualOpConcept<
1290             typename iterator_traits<_InputIterator1>::value_type,
1291             typename iterator_traits<_InputIterator2>::value_type>)
1292       __glibcxx_requires_valid_range(__first1, __last1);
1293
1294       return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2,
1295                              __gnu_cxx::__ops::__iter_equal_to_iter());
1296     }
1297
1298   /**
1299    *  @brief Finds the places in ranges which don't match.
1300    *  @ingroup non_mutating_algorithms
1301    *  @param  __first1  An input iterator.
1302    *  @param  __last1   An input iterator.
1303    *  @param  __first2  An input iterator.
1304    *  @param __binary_pred A binary predicate @link functors
1305    *         functor@endlink.
1306    *  @return   A pair of iterators pointing to the first mismatch.
1307    *
1308    *  This compares the elements of two ranges using the binary_pred
1309    *  parameter, and returns a pair
1310    *  of iterators.  The first iterator points into the first range, the
1311    *  second iterator points into the second range, and the elements pointed
1312    *  to by the iterators are not equal.
1313   */
1314   template<typename _InputIterator1, typename _InputIterator2,
1315            typename _BinaryPredicate>
1316     inline pair<_InputIterator1, _InputIterator2>
1317     mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1318              _InputIterator2 __first2, _BinaryPredicate __binary_pred)
1319     {
1320       // concept requirements
1321       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
1322       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
1323       __glibcxx_requires_valid_range(__first1, __last1);
1324
1325       return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2,
1326         __gnu_cxx::__ops::__iter_comp_iter(__binary_pred));
1327     }
1328
1329 #if __cplusplus > 201103L
1330
1331   template<typename _InputIterator1, typename _InputIterator2,
1332            typename _BinaryPredicate>
1333     pair<_InputIterator1, _InputIterator2>
1334     __mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1335                _InputIterator2 __first2, _InputIterator2 __last2,
1336                _BinaryPredicate __binary_pred)
1337     {
1338       while (__first1 != __last1 && __first2 != __last2
1339              && __binary_pred(__first1, __first2))
1340         {
1341           ++__first1;
1342           ++__first2;
1343         }
1344       return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
1345     }
1346
1347   /**
1348    *  @brief Finds the places in ranges which don't match.
1349    *  @ingroup non_mutating_algorithms
1350    *  @param  __first1  An input iterator.
1351    *  @param  __last1   An input iterator.
1352    *  @param  __first2  An input iterator.
1353    *  @param  __last2   An input iterator.
1354    *  @return   A pair of iterators pointing to the first mismatch.
1355    *
1356    *  This compares the elements of two ranges using @c == and returns a pair
1357    *  of iterators.  The first iterator points into the first range, the
1358    *  second iterator points into the second range, and the elements pointed
1359    *  to by the iterators are not equal.
1360   */
1361   template<typename _InputIterator1, typename _InputIterator2>
1362     inline pair<_InputIterator1, _InputIterator2>
1363     mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1364              _InputIterator2 __first2, _InputIterator2 __last2)
1365     {
1366       // concept requirements
1367       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
1368       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
1369       __glibcxx_function_requires(_EqualOpConcept<
1370             typename iterator_traits<_InputIterator1>::value_type,
1371             typename iterator_traits<_InputIterator2>::value_type>)
1372       __glibcxx_requires_valid_range(__first1, __last1);
1373       __glibcxx_requires_valid_range(__first2, __last2);
1374
1375       return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2, __last2,
1376                              __gnu_cxx::__ops::__iter_equal_to_iter());
1377     }
1378
1379   /**
1380    *  @brief Finds the places in ranges which don't match.
1381    *  @ingroup non_mutating_algorithms
1382    *  @param  __first1  An input iterator.
1383    *  @param  __last1   An input iterator.
1384    *  @param  __first2  An input iterator.
1385    *  @param  __last2   An input iterator.
1386    *  @param __binary_pred A binary predicate @link functors
1387    *         functor@endlink.
1388    *  @return   A pair of iterators pointing to the first mismatch.
1389    *
1390    *  This compares the elements of two ranges using the binary_pred
1391    *  parameter, and returns a pair
1392    *  of iterators.  The first iterator points into the first range, the
1393    *  second iterator points into the second range, and the elements pointed
1394    *  to by the iterators are not equal.
1395   */
1396   template<typename _InputIterator1, typename _InputIterator2,
1397            typename _BinaryPredicate>
1398     inline pair<_InputIterator1, _InputIterator2>
1399     mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1400              _InputIterator2 __first2, _InputIterator2 __last2,
1401              _BinaryPredicate __binary_pred)
1402     {
1403       // concept requirements
1404       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
1405       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
1406       __glibcxx_requires_valid_range(__first1, __last1);
1407       __glibcxx_requires_valid_range(__first2, __last2);
1408
1409       return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2, __last2,
1410                              __gnu_cxx::__ops::__iter_comp_iter(__binary_pred));
1411     }
1412 #endif
1413
1414 _GLIBCXX_END_NAMESPACE_ALGO
1415 } // namespace std
1416
1417 // NB: This file is included within many other C++ includes, as a way
1418 // of getting the base algorithms. So, make sure that parallel bits
1419 // come in too if requested.
1420 #ifdef _GLIBCXX_PARALLEL
1421 # include <parallel/algobase.h>
1422 #endif
1423
1424 #endif