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   // Likewise for move_iterator.
 281   template<typename _Iterator>
 282     inline _Iterator
 283     __miter_base(_Iterator __it)
 284     { return __it; }
 285
 286   // All of these auxiliary structs serve two purposes.  (1) Replace
 287   // calls to copy with memmove whenever possible.  (Memmove, not memcpy,
 288   // because the input and output ranges are permitted to overlap.)
 289   // (2) If we're using random access iterators, then write the loop as
 290   // a for loop with an explicit count.
 291
 292   template<bool, bool, typename>
 293     struct __copy_move
 294     {
 295       template<typename _II, typename _OI>
 296         static _OI
 297         __copy_m(_II __first, _II __last, _OI __result)
 298         {
 299           for (; __first != __last; ++__result, (void)++__first)
 300             *__result = *__first;
 301           return __result;
 302         }
 303     };
 304
 305 #if __cplusplus >= 201103L
 306   template<typename _Category>
 307     struct __copy_move<true, false, _Category>
 308     {
 309       template<typename _II, typename _OI>
 310         static _OI
 311         __copy_m(_II __first, _II __last, _OI __result)
 312         {
 313           for (; __first != __last; ++__result, (void)++__first)
 314             *__result = std::move(*__first);
 315           return __result;
 316         }
 317     };
 318 #endif
 319
 320   template<>
 321     struct __copy_move<false, false, random_access_iterator_tag>
 322     {
 323       template<typename _II, typename _OI>
 324         static _OI
 325         __copy_m(_II __first, _II __last, _OI __result)
 326         {
 327           typedef typename iterator_traits<_II>::difference_type _Distance;
 328           for(_Distance __n = __last - __first; __n > 0; --__n)
 329             {
 330               *__result = *__first;
 331               ++__first;
 332               ++__result;
 333             }
 334           return __result;
 335         }
 336     };
 337
 338 #if __cplusplus >= 201103L
 339   template<>
 340     struct __copy_move<true, false, random_access_iterator_tag>
 341     {
 342       template<typename _II, typename _OI>
 343         static _OI
 344         __copy_m(_II __first, _II __last, _OI __result)
 345         {
 346           typedef typename iterator_traits<_II>::difference_type _Distance;
 347           for(_Distance __n = __last - __first; __n > 0; --__n)
 348             {
 349               *__result = std::move(*__first);
 350               ++__first;
 351               ++__result;
 352             }
 353           return __result;
 354         }
 355     };
 356 #endif
 357
 358   template<bool _IsMove>
 359     struct __copy_move<_IsMove, true, random_access_iterator_tag>
 360     {
 361       template<typename _Tp>
 362         static _Tp*
 363         __copy_m(const _Tp* __first, const _Tp* __last, _Tp* __result)
 364         {
 365 #if __cplusplus >= 201103L
 366           // trivial types can have deleted assignment
 367           static_assert( is_copy_assignable<_Tp>::value,
 368                          "type is not assignable" );
 369 #endif
 370           const ptrdiff_t _Num = __last - __first;
 371           if (_Num)
 372             __builtin_memmove(__result, __first, sizeof(_Tp) * _Num);
 373           return __result + _Num;
 374         }
 375     };
 376
 377   template<bool _IsMove, typename _II, typename _OI>
 378     inline _OI
 379     __copy_move_a(_II __first, _II __last, _OI __result)
 380     {
 381       typedef typename iterator_traits<_II>::value_type _ValueTypeI;
 382       typedef typename iterator_traits<_OI>::value_type _ValueTypeO;
 383       typedef typename iterator_traits<_II>::iterator_category _Category;
 384       const bool __simple = (__is_trivial(_ValueTypeI)
 385                              && __is_pointer<_II>::__value
 386                              && __is_pointer<_OI>::__value
 387                              && __are_same<_ValueTypeI, _ValueTypeO>::__value);
 388
 389       return std::__copy_move<_IsMove, __simple,
 390                               _Category>::__copy_m(__first, __last, __result);
 391     }
 392
 393   // Helpers for streambuf iterators (either istream or ostream).
 394   // NB: avoid including <iosfwd>, relatively large.
 395   template<typename _CharT>
 396     struct char_traits;
 397
 398   template<typename _CharT, typename _Traits>
 399     class istreambuf_iterator;
 400
 401   template<typename _CharT, typename _Traits>
 402     class ostreambuf_iterator;
 403
 404   template<bool _IsMove, typename _CharT>
 405     typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
 406              ostreambuf_iterator<_CharT, char_traits<_CharT> > >::__type
 407     __copy_move_a2(_CharT*, _CharT*,
 408                    ostreambuf_iterator<_CharT, char_traits<_CharT> >);
 409
 410   template<bool _IsMove, typename _CharT>
 411     typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
 412              ostreambuf_iterator<_CharT, char_traits<_CharT> > >::__type
 413     __copy_move_a2(const _CharT*, const _CharT*,
 414                    ostreambuf_iterator<_CharT, char_traits<_CharT> >);
 415
 416   template<bool _IsMove, typename _CharT>
 417     typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
 418                                     _CharT*>::__type
 419     __copy_move_a2(istreambuf_iterator<_CharT, char_traits<_CharT> >,
 420                    istreambuf_iterator<_CharT, char_traits<_CharT> >, _CharT*);
 421
 422   template<bool _IsMove, typename _II, typename _OI>
 423     inline _OI
 424     __copy_move_a2(_II __first, _II __last, _OI __result)
 425     {
 426       return _OI(std::__copy_move_a<_IsMove>(std::__niter_base(__first),
 427                                              std::__niter_base(__last),
 428                                              std::__niter_base(__result)));
 429     }
 430
 431   /**
 432    *  @brief Copies the range [first,last) into result.
 433    *  @ingroup mutating_algorithms
 434    *  @param  __first  An input iterator.
 435    *  @param  __last   An input iterator.
 436    *  @param  __result An output iterator.
 437    *  @return   result + (first - last)
 438    *
 439    *  This inline function will boil down to a call to @c memmove whenever
 440    *  possible.  Failing that, if random access iterators are passed, then the
 441    *  loop count will be known (and therefore a candidate for compiler
 442    *  optimizations such as unrolling).  Result may not be contained within
 443    *  [first,last); the copy_backward function should be used instead.
 444    *
 445    *  Note that the end of the output range is permitted to be contained
 446    *  within [first,last).
 447   */
 448   template<typename _II, typename _OI>
 449     inline _OI
 450     copy(_II __first, _II __last, _OI __result)
 451     {
 452       // concept requirements
 453       __glibcxx_function_requires(_InputIteratorConcept<_II>)
 454       __glibcxx_function_requires(_OutputIteratorConcept<_OI,
 455             typename iterator_traits<_II>::value_type>)
 456       __glibcxx_requires_valid_range(__first, __last);
 457
 458       return (std::__copy_move_a2<__is_move_iterator<_II>::__value>
 459               (std::__miter_base(__first), std::__miter_base(__last),
 460                __result));
 461     }
 462
 463 #if __cplusplus >= 201103L
 464   /**
 465    *  @brief Moves the range [first,last) into result.
 466    *  @ingroup mutating_algorithms
 467    *  @param  __first  An input iterator.
 468    *  @param  __last   An input iterator.
 469    *  @param  __result An output iterator.
 470    *  @return   result + (first - last)
 471    *
 472    *  This inline function will boil down to a call to @c memmove whenever
 473    *  possible.  Failing that, if random access iterators are passed, then the
 474    *  loop count will be known (and therefore a candidate for compiler
 475    *  optimizations such as unrolling).  Result may not be contained within
 476    *  [first,last); the move_backward function should be used instead.
 477    *
 478    *  Note that the end of the output range is permitted to be contained
 479    *  within [first,last).
 480   */
 481   template<typename _II, typename _OI>
 482     inline _OI
 483     move(_II __first, _II __last, _OI __result)
 484     {
 485       // concept requirements
 486       __glibcxx_function_requires(_InputIteratorConcept<_II>)
 487       __glibcxx_function_requires(_OutputIteratorConcept<_OI,
 488             typename iterator_traits<_II>::value_type>)
 489       __glibcxx_requires_valid_range(__first, __last);
 490
 491       return std::__copy_move_a2<true>(std::__miter_base(__first),
 492                                        std::__miter_base(__last), __result);
 493     }
 494
 495 #define _GLIBCXX_MOVE3(_Tp, _Up, _Vp) std::move(_Tp, _Up, _Vp)
 496 #else
 497 #define _GLIBCXX_MOVE3(_Tp, _Up, _Vp) std::copy(_Tp, _Up, _Vp)
 498 #endif
 499
 500   template<bool, bool, typename>
 501     struct __copy_move_backward
 502     {
 503       template<typename _BI1, typename _BI2>
 504         static _BI2
 505         __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
 506         {
 507           while (__first != __last)
 508             *--__result = *--__last;
 509           return __result;
 510         }
 511     };
 512
 513 #if __cplusplus >= 201103L
 514   template<typename _Category>
 515     struct __copy_move_backward<true, false, _Category>
 516     {
 517       template<typename _BI1, typename _BI2>
 518         static _BI2
 519         __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
 520         {
 521           while (__first != __last)
 522             *--__result = std::move(*--__last);
 523           return __result;
 524         }
 525     };
 526 #endif
 527
 528   template<>
 529     struct __copy_move_backward<false, false, random_access_iterator_tag>
 530     {
 531       template<typename _BI1, typename _BI2>
 532         static _BI2
 533         __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
 534         {
 535           typename iterator_traits<_BI1>::difference_type __n;
 536           for (__n = __last - __first; __n > 0; --__n)
 537             *--__result = *--__last;
 538           return __result;
 539         }
 540     };
 541
 542 #if __cplusplus >= 201103L
 543   template<>
 544     struct __copy_move_backward<true, false, random_access_iterator_tag>
 545     {
 546       template<typename _BI1, typename _BI2>
 547         static _BI2
 548         __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
 549         {
 550           typename iterator_traits<_BI1>::difference_type __n;
 551           for (__n = __last - __first; __n > 0; --__n)
 552             *--__result = std::move(*--__last);
 553           return __result;
 554         }
 555     };
 556 #endif
 557
 558   template<bool _IsMove>
 559     struct __copy_move_backward<_IsMove, true, random_access_iterator_tag>
 560     {
 561       template<typename _Tp>
 562         static _Tp*
 563         __copy_move_b(const _Tp* __first, const _Tp* __last, _Tp* __result)
 564         {
 565 #if __cplusplus >= 201103L
 566           // trivial types can have deleted assignment
 567           static_assert( is_copy_assignable<_Tp>::value,
 568                          "type is not assignable" );
 569 #endif
 570           const ptrdiff_t _Num = __last - __first;
 571           if (_Num)
 572             __builtin_memmove(__result - _Num, __first, sizeof(_Tp) * _Num);
 573           return __result - _Num;
 574         }
 575     };
 576
 577   template<bool _IsMove, typename _BI1, typename _BI2>
 578     inline _BI2
 579     __copy_move_backward_a(_BI1 __first, _BI1 __last, _BI2 __result)
 580     {
 581       typedef typename iterator_traits<_BI1>::value_type _ValueType1;
 582       typedef typename iterator_traits<_BI2>::value_type _ValueType2;
 583       typedef typename iterator_traits<_BI1>::iterator_category _Category;
 584       const bool __simple = (__is_trivial(_ValueType1)
 585                              && __is_pointer<_BI1>::__value
 586                              && __is_pointer<_BI2>::__value
 587                              && __are_same<_ValueType1, _ValueType2>::__value);
 588
 589       return std::__copy_move_backward<_IsMove, __simple,
 590                                        _Category>::__copy_move_b(__first,
 591                                                                  __last,
 592                                                                  __result);
 593     }
 594
 595   template<bool _IsMove, typename _BI1, typename _BI2>
 596     inline _BI2
 597     __copy_move_backward_a2(_BI1 __first, _BI1 __last, _BI2 __result)
 598     {
 599       return _BI2(std::__copy_move_backward_a<_IsMove>
 600                   (std::__niter_base(__first), std::__niter_base(__last),
 601                    std::__niter_base(__result)));
 602     }
 603
 604   /**
 605    *  @brief Copies the range [first,last) into result.
 606    *  @ingroup mutating_algorithms
 607    *  @param  __first  A bidirectional iterator.
 608    *  @param  __last   A bidirectional iterator.
 609    *  @param  __result A bidirectional iterator.
 610    *  @return   result - (first - last)
 611    *
 612    *  The function has the same effect as copy, but starts at the end of the
 613    *  range and works its way to the start, returning the start of the result.
 614    *  This inline function will boil down to a call to @c memmove whenever
 615    *  possible.  Failing that, if random access iterators are passed, then the
 616    *  loop count will be known (and therefore a candidate for compiler
 617    *  optimizations such as unrolling).
 618    *
 619    *  Result may not be in the range (first,last].  Use copy instead.  Note
 620    *  that the start of the output range may overlap [first,last).
 621   */
 622   template<typename _BI1, typename _BI2>
 623     inline _BI2
 624     copy_backward(_BI1 __first, _BI1 __last, _BI2 __result)
 625     {
 626       // concept requirements
 627       __glibcxx_function_requires(_BidirectionalIteratorConcept<_BI1>)
 628       __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<_BI2>)
 629       __glibcxx_function_requires(_ConvertibleConcept<
 630             typename iterator_traits<_BI1>::value_type,
 631             typename iterator_traits<_BI2>::value_type>)
 632       __glibcxx_requires_valid_range(__first, __last);
 633
 634       return (std::__copy_move_backward_a2<__is_move_iterator<_BI1>::__value>
 635               (std::__miter_base(__first), std::__miter_base(__last),
 636                __result));
 637     }
 638
 639 #if __cplusplus >= 201103L
 640   /**
 641    *  @brief Moves the range [first,last) into result.
 642    *  @ingroup mutating_algorithms
 643    *  @param  __first  A bidirectional iterator.
 644    *  @param  __last   A bidirectional iterator.
 645    *  @param  __result A bidirectional iterator.
 646    *  @return   result - (first - last)
 647    *
 648    *  The function has the same effect as move, but starts at the end of the
 649    *  range and works its way to the start, returning the start of the result.
 650    *  This inline function will boil down to a call to @c memmove whenever
 651    *  possible.  Failing that, if random access iterators are passed, then the
 652    *  loop count will be known (and therefore a candidate for compiler
 653    *  optimizations such as unrolling).
 654    *
 655    *  Result may not be in the range (first,last].  Use move instead.  Note
 656    *  that the start of the output range may overlap [first,last).
 657   */
 658   template<typename _BI1, typename _BI2>
 659     inline _BI2
 660     move_backward(_BI1 __first, _BI1 __last, _BI2 __result)
 661     {
 662       // concept requirements
 663       __glibcxx_function_requires(_BidirectionalIteratorConcept<_BI1>)
 664       __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<_BI2>)
 665       __glibcxx_function_requires(_ConvertibleConcept<
 666             typename iterator_traits<_BI1>::value_type,
 667             typename iterator_traits<_BI2>::value_type>)
 668       __glibcxx_requires_valid_range(__first, __last);
 669
 670       return std::__copy_move_backward_a2<true>(std::__miter_base(__first),
 671                                                 std::__miter_base(__last),
 672                                                 __result);
 673     }
 674
 675 #define _GLIBCXX_MOVE_BACKWARD3(_Tp, _Up, _Vp) std::move_backward(_Tp, _Up, _Vp)
 676 #else
 677 #define _GLIBCXX_MOVE_BACKWARD3(_Tp, _Up, _Vp) std::copy_backward(_Tp, _Up, _Vp)
 678 #endif
 679
 680   template<typename _ForwardIterator, typename _Tp>
 681     inline typename
 682     __gnu_cxx::__enable_if<!__is_scalar<_Tp>::__value, void>::__type
 683     __fill_a(_ForwardIterator __first, _ForwardIterator __last,
 684              const _Tp& __value)
 685     {
 686       for (; __first != __last; ++__first)
 687         *__first = __value;
 688     }
 689
 690   template<typename _ForwardIterator, typename _Tp>
 691     inline typename
 692     __gnu_cxx::__enable_if<__is_scalar<_Tp>::__value, void>::__type
 693     __fill_a(_ForwardIterator __first, _ForwardIterator __last,
 694              const _Tp& __value)
 695     {
 696       const _Tp __tmp = __value;
 697       for (; __first != __last; ++__first)
 698         *__first = __tmp;
 699     }
 700
 701   // Specialization: for char types we can use memset.
 702   template<typename _Tp>
 703     inline typename
 704     __gnu_cxx::__enable_if<__is_byte<_Tp>::__value, void>::__type
 705     __fill_a(_Tp* __first, _Tp* __last, const _Tp& __c)
 706     {
 707       const _Tp __tmp = __c;
 708       if (const size_t __len = __last - __first)
 709         __builtin_memset(__first, static_cast<unsigned char>(__tmp), __len);
 710     }
 711
 712   /**
 713    *  @brief Fills the range [first,last) with copies of value.
 714    *  @ingroup mutating_algorithms
 715    *  @param  __first  A forward iterator.
 716    *  @param  __last   A forward iterator.
 717    *  @param  __value  A reference-to-const of arbitrary type.
 718    *  @return   Nothing.
 719    *
 720    *  This function fills a range with copies of the same value.  For char
 721    *  types filling contiguous areas of memory, this becomes an inline call
 722    *  to @c memset or @c wmemset.
 723   */
 724   template<typename _ForwardIterator, typename _Tp>
 725     inline void
 726     fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value)
 727     {
 728       // concept requirements
 729       __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
 730                                   _ForwardIterator>)
 731       __glibcxx_requires_valid_range(__first, __last);
 732
 733       std::__fill_a(std::__niter_base(__first), std::__niter_base(__last),
 734                     __value);
 735     }
 736
 737   template<typename _OutputIterator, typename _Size, typename _Tp>
 738     inline typename
 739     __gnu_cxx::__enable_if<!__is_scalar<_Tp>::__value, _OutputIterator>::__type
 740     __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value)
 741     {
 742       for (__decltype(__n + 0) __niter = __n;
 743            __niter > 0; --__niter, ++__first)
 744         *__first = __value;
 745       return __first;
 746     }
 747
 748   template<typename _OutputIterator, typename _Size, typename _Tp>
 749     inline typename
 750     __gnu_cxx::__enable_if<__is_scalar<_Tp>::__value, _OutputIterator>::__type
 751     __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value)
 752     {
 753       const _Tp __tmp = __value;
 754       for (__decltype(__n + 0) __niter = __n;
 755            __niter > 0; --__niter, ++__first)
 756         *__first = __tmp;
 757       return __first;
 758     }
 759
 760   template<typename _Size, typename _Tp>
 761     inline typename
 762     __gnu_cxx::__enable_if<__is_byte<_Tp>::__value, _Tp*>::__type
 763     __fill_n_a(_Tp* __first, _Size __n, const _Tp& __c)
 764     {
 765       std::__fill_a(__first, __first + __n, __c);
 766       return __first + __n;
 767     }
 768
 769   /**
 770    *  @brief Fills the range [first,first+n) with copies of value.
 771    *  @ingroup mutating_algorithms
 772    *  @param  __first  An output iterator.
 773    *  @param  __n      The count of copies to perform.
 774    *  @param  __value  A reference-to-const of arbitrary type.
 775    *  @return   The iterator at first+n.
 776    *
 777    *  This function fills a range with copies of the same value.  For char
 778    *  types filling contiguous areas of memory, this becomes an inline call
 779    *  to @c memset or @ wmemset.
 780    *
 781    *  _GLIBCXX_RESOLVE_LIB_DEFECTS
 782    *  DR 865. More algorithms that throw away information
 783   */
 784   template<typename _OI, typename _Size, typename _Tp>
 785     inline _OI
 786     fill_n(_OI __first, _Size __n, const _Tp& __value)
 787     {
 788       // concept requirements
 789       __glibcxx_function_requires(_OutputIteratorConcept<_OI, _Tp>)
 790
 791       return _OI(std::__fill_n_a(std::__niter_base(__first), __n, __value));
 792     }
 793
 794   template<bool _BoolType>
 795     struct __equal
 796     {
 797       template<typename _II1, typename _II2>
 798         static bool
 799         equal(_II1 __first1, _II1 __last1, _II2 __first2)
 800         {
 801           for (; __first1 != __last1; ++__first1, (void)++__first2)
 802             if (!(*__first1 == *__first2))
 803               return false;
 804           return true;
 805         }
 806     };
 807
 808   template<>
 809     struct __equal<true>
 810     {
 811       template<typename _Tp>
 812         static bool
 813         equal(const _Tp* __first1, const _Tp* __last1, const _Tp* __first2)
 814         {
 815           if (const size_t __len = (__last1 - __first1))
 816             return !__builtin_memcmp(__first1, __first2, sizeof(_Tp) * __len);
 817           return true;
 818         }
 819     };
 820
 821   template<typename _II1, typename _II2>
 822     inline bool
 823     __equal_aux(_II1 __first1, _II1 __last1, _II2 __first2)
 824     {
 825       typedef typename iterator_traits<_II1>::value_type _ValueType1;
 826       typedef typename iterator_traits<_II2>::value_type _ValueType2;
 827       const bool __simple = ((__is_integer<_ValueType1>::__value
 828                               || __is_pointer<_ValueType1>::__value)
 829                              && __is_pointer<_II1>::__value
 830                              && __is_pointer<_II2>::__value
 831                              && __are_same<_ValueType1, _ValueType2>::__value);
 832
 833       return std::__equal<__simple>::equal(__first1, __last1, __first2);
 834     }
 835
 836   template<typename, typename>
 837     struct __lc_rai
 838     {
 839       template<typename _II1, typename _II2>
 840         static _II1
 841         __newlast1(_II1, _II1 __last1, _II2, _II2)
 842         { return __last1; }
 843
 844       template<typename _II>
 845         static bool
 846         __cnd2(_II __first, _II __last)
 847         { return __first != __last; }
 848     };
 849
 850   template<>
 851     struct __lc_rai<random_access_iterator_tag, random_access_iterator_tag>
 852     {
 853       template<typename _RAI1, typename _RAI2>
 854         static _RAI1
 855         __newlast1(_RAI1 __first1, _RAI1 __last1,
 856                    _RAI2 __first2, _RAI2 __last2)
 857         {
 858           const typename iterator_traits<_RAI1>::difference_type
 859             __diff1 = __last1 - __first1;
 860           const typename iterator_traits<_RAI2>::difference_type
 861             __diff2 = __last2 - __first2;
 862           return __diff2 < __diff1 ? __first1 + __diff2 : __last1;
 863         }
 864
 865       template<typename _RAI>
 866         static bool
 867         __cnd2(_RAI, _RAI)
 868         { return true; }
 869     };
 870
 871   template<typename _II1, typename _II2, typename _Compare>
 872     bool
 873     __lexicographical_compare_impl(_II1 __first1, _II1 __last1,
 874                                    _II2 __first2, _II2 __last2,
 875                                    _Compare __comp)
 876     {
 877       typedef typename iterator_traits<_II1>::iterator_category _Category1;
 878       typedef typename iterator_traits<_II2>::iterator_category _Category2;
 879       typedef std::__lc_rai<_Category1, _Category2> __rai_type;
 880
 881       __last1 = __rai_type::__newlast1(__first1, __last1, __first2, __last2);
 882       for (; __first1 != __last1 && __rai_type::__cnd2(__first2, __last2);
 883            ++__first1, (void)++__first2)
 884         {
 885           if (__comp(__first1, __first2))
 886             return true;
 887           if (__comp(__first2, __first1))
 888             return false;
 889         }
 890       return __first1 == __last1 && __first2 != __last2;
 891     }
 892
 893   template<bool _BoolType>
 894     struct __lexicographical_compare
 895     {
 896       template<typename _II1, typename _II2>
 897         static bool __lc(_II1, _II1, _II2, _II2);
 898     };
 899
 900   template<bool _BoolType>
 901     template<typename _II1, typename _II2>
 902       bool
 903       __lexicographical_compare<_BoolType>::
 904       __lc(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
 905       {
 906         return std::__lexicographical_compare_impl(__first1, __last1,
 907                                                    __first2, __last2,
 908                                         __gnu_cxx::__ops::__iter_less_iter());
 909       }
 910
 911   template<>
 912     struct __lexicographical_compare<true>
 913     {
 914       template<typename _Tp, typename _Up>
 915         static bool
 916         __lc(const _Tp* __first1, const _Tp* __last1,
 917              const _Up* __first2, const _Up* __last2)
 918         {
 919           const size_t __len1 = __last1 - __first1;
 920           const size_t __len2 = __last2 - __first2;
 921           if (const size_t __len = std::min(__len1, __len2))
 922             if (int __result = __builtin_memcmp(__first1, __first2, __len))
 923               return __result < 0;
 924           return __len1 < __len2;
 925         }
 926     };
 927
 928   template<typename _II1, typename _II2>
 929     inline bool
 930     __lexicographical_compare_aux(_II1 __first1, _II1 __last1,
 931                                   _II2 __first2, _II2 __last2)
 932     {
 933       typedef typename iterator_traits<_II1>::value_type _ValueType1;
 934       typedef typename iterator_traits<_II2>::value_type _ValueType2;
 935       const bool __simple =
 936         (__is_byte<_ValueType1>::__value && __is_byte<_ValueType2>::__value
 937          && !__gnu_cxx::__numeric_traits<_ValueType1>::__is_signed
 938          && !__gnu_cxx::__numeric_traits<_ValueType2>::__is_signed
 939          && __is_pointer<_II1>::__value
 940          && __is_pointer<_II2>::__value);
 941
 942       return std::__lexicographical_compare<__simple>::__lc(__first1, __last1,
 943                                                             __first2, __last2);
 944     }
 945
 946   template<typename _ForwardIterator, typename _Tp, typename _Compare>
 947     _ForwardIterator
 948     __lower_bound(_ForwardIterator __first, _ForwardIterator __last,
 949                   const _Tp& __val, _Compare __comp)
 950     {
 951       typedef typename iterator_traits<_ForwardIterator>::difference_type
 952         _DistanceType;
 953
 954       _DistanceType __len = std::distance(__first, __last);
 955
 956       while (__len > 0)
 957         {
 958           _DistanceType __half = __len >> 1;
 959           _ForwardIterator __middle = __first;
 960           std::advance(__middle, __half);
 961           if (__comp(__middle, __val))
 962             {
 963               __first = __middle;
 964               ++__first;
 965               __len = __len - __half - 1;
 966             }
 967           else
 968             __len = __half;
 969         }
 970       return __first;
 971     }
 972
 973   /**
 974    *  @brief Finds the first position in which @a val could be inserted
 975    *         without changing the ordering.
 976    *  @param  __first   An iterator.
 977    *  @param  __last    Another iterator.
 978    *  @param  __val     The search term.
 979    *  @return         An iterator pointing to the first element <em>not less
 980    *                  than</em> @a val, or end() if every element is less than
 981    *                  @a val.
 982    *  @ingroup binary_search_algorithms
 983   */
 984   template<typename _ForwardIterator, typename _Tp>
 985     inline _ForwardIterator
 986     lower_bound(_ForwardIterator __first, _ForwardIterator __last,
 987                 const _Tp& __val)
 988     {
 989       // concept requirements
 990       __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
 991       __glibcxx_function_requires(_LessThanOpConcept<
 992             typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
 993       __glibcxx_requires_partitioned_lower(__first, __last, __val);
 994
 995       return std::__lower_bound(__first, __last, __val,
 996                                 __gnu_cxx::__ops::__iter_less_val());
 997     }
 998
 999   /// This is a helper function for the sort routines and for random.tcc.
1000   //  Precondition: __n > 0.
1001   inline _GLIBCXX_CONSTEXPR int
1002   __lg(int __n)
1003   { return sizeof(int) * __CHAR_BIT__  - 1 - __builtin_clz(__n); }
1004
1005   inline _GLIBCXX_CONSTEXPR unsigned
1006   __lg(unsigned __n)
1007   { return sizeof(int) * __CHAR_BIT__  - 1 - __builtin_clz(__n); }
1008
1009   inline _GLIBCXX_CONSTEXPR long
1010   __lg(long __n)
1011   { return sizeof(long) * __CHAR_BIT__ - 1 - __builtin_clzl(__n); }
1012
1013   inline _GLIBCXX_CONSTEXPR unsigned long
1014   __lg(unsigned long __n)
1015   { return sizeof(long) * __CHAR_BIT__ - 1 - __builtin_clzl(__n); }
1016
1017   inline _GLIBCXX_CONSTEXPR long long
1018   __lg(long long __n)
1019   { return sizeof(long long) * __CHAR_BIT__ - 1 - __builtin_clzll(__n); }
1020
1021   inline _GLIBCXX_CONSTEXPR unsigned long long
1022   __lg(unsigned long long __n)
1023   { return sizeof(long long) * __CHAR_BIT__ - 1 - __builtin_clzll(__n); }
1024
1025 _GLIBCXX_END_NAMESPACE_VERSION
1026
1027 _GLIBCXX_BEGIN_NAMESPACE_ALGO
1028
1029   /**
1030    *  @brief Tests a range for element-wise equality.
1031    *  @ingroup non_mutating_algorithms
1032    *  @param  __first1  An input iterator.
1033    *  @param  __last1   An input iterator.
1034    *  @param  __first2  An input iterator.
1035    *  @return   A boolean true or false.
1036    *
1037    *  This compares the elements of two ranges using @c == and returns true or
1038    *  false depending on whether all of the corresponding elements of the
1039    *  ranges are equal.
1040   */
1041   template<typename _II1, typename _II2>
1042     inline bool
1043     equal(_II1 __first1, _II1 __last1, _II2 __first2)
1044     {
1045       // concept requirements
1046       __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1047       __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1048       __glibcxx_function_requires(_EqualOpConcept<
1049             typename iterator_traits<_II1>::value_type,
1050             typename iterator_traits<_II2>::value_type>)
1051       __glibcxx_requires_valid_range(__first1, __last1);
1052
1053       return std::__equal_aux(std::__niter_base(__first1),
1054                               std::__niter_base(__last1),
1055                               std::__niter_base(__first2));
1056     }
1057
1058   /**
1059    *  @brief Tests a range for element-wise equality.
1060    *  @ingroup non_mutating_algorithms
1061    *  @param  __first1  An input iterator.
1062    *  @param  __last1   An input iterator.
1063    *  @param  __first2  An input iterator.
1064    *  @param __binary_pred A binary predicate @link functors
1065    *                  functor@endlink.
1066    *  @return         A boolean true or false.
1067    *
1068    *  This compares the elements of two ranges using the binary_pred
1069    *  parameter, and returns true or
1070    *  false depending on whether all of the corresponding elements of the
1071    *  ranges are equal.
1072   */
1073   template<typename _IIter1, typename _IIter2, typename _BinaryPredicate>
1074     inline bool
1075     equal(_IIter1 __first1, _IIter1 __last1,
1076           _IIter2 __first2, _BinaryPredicate __binary_pred)
1077     {
1078       // concept requirements
1079       __glibcxx_function_requires(_InputIteratorConcept<_IIter1>)
1080       __glibcxx_function_requires(_InputIteratorConcept<_IIter2>)
1081       __glibcxx_requires_valid_range(__first1, __last1);
1082
1083       for (; __first1 != __last1; ++__first1, (void)++__first2)
1084         if (!bool(__binary_pred(*__first1, *__first2)))
1085           return false;
1086       return true;
1087     }
1088
1089 #if __cplusplus > 201103L
1090
1091 #define __cpp_lib_robust_nonmodifying_seq_ops 201304
1092
1093   /**
1094    *  @brief Tests a range for element-wise equality.
1095    *  @ingroup non_mutating_algorithms
1096    *  @param  __first1  An input iterator.
1097    *  @param  __last1   An input iterator.
1098    *  @param  __first2  An input iterator.
1099    *  @param  __last2   An input iterator.
1100    *  @return   A boolean true or false.
1101    *
1102    *  This compares the elements of two ranges using @c == and returns true or
1103    *  false depending on whether all of the corresponding elements of the
1104    *  ranges are equal.
1105   */
1106   template<typename _II1, typename _II2>
1107     inline bool
1108     equal(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
1109     {
1110       // concept requirements
1111       __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1112       __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1113       __glibcxx_function_requires(_EqualOpConcept<
1114             typename iterator_traits<_II1>::value_type,
1115             typename iterator_traits<_II2>::value_type>)
1116       __glibcxx_requires_valid_range(__first1, __last1);
1117       __glibcxx_requires_valid_range(__first2, __last2);
1118
1119       using _RATag = random_access_iterator_tag;
1120       using _Cat1 = typename iterator_traits<_II1>::iterator_category;
1121       using _Cat2 = typename iterator_traits<_II2>::iterator_category;
1122       using _RAIters = __and_<is_same<_Cat1, _RATag>, is_same<_Cat2, _RATag>>;
1123       if (_RAIters())
1124         {
1125           auto __d1 = std::distance(__first1, __last1);
1126           auto __d2 = std::distance(__first2, __last2);
1127           if (__d1 != __d2)
1128             return false;
1129           return _GLIBCXX_STD_A::equal(__first1, __last1, __first2);
1130         }
1131
1132       for (; __first1 != __last1 && __first2 != __last2;
1133           ++__first1, (void)++__first2)
1134         if (!(*__first1 == *__first2))
1135           return false;
1136       return __first1 == __last1 && __first2 == __last2;
1137     }
1138
1139   /**
1140    *  @brief Tests a range for element-wise equality.
1141    *  @ingroup non_mutating_algorithms
1142    *  @param  __first1  An input iterator.
1143    *  @param  __last1   An input iterator.
1144    *  @param  __first2  An input iterator.
1145    *  @param  __last2   An input iterator.
1146    *  @param __binary_pred A binary predicate @link functors
1147    *                  functor@endlink.
1148    *  @return         A boolean true or false.
1149    *
1150    *  This compares the elements of two ranges using the binary_pred
1151    *  parameter, and returns true or
1152    *  false depending on whether all of the corresponding elements of the
1153    *  ranges are equal.
1154   */
1155   template<typename _IIter1, typename _IIter2, typename _BinaryPredicate>
1156     inline bool
1157     equal(_IIter1 __first1, _IIter1 __last1,
1158           _IIter2 __first2, _IIter2 __last2, _BinaryPredicate __binary_pred)
1159     {
1160       // concept requirements
1161       __glibcxx_function_requires(_InputIteratorConcept<_IIter1>)
1162       __glibcxx_function_requires(_InputIteratorConcept<_IIter2>)
1163       __glibcxx_requires_valid_range(__first1, __last1);
1164       __glibcxx_requires_valid_range(__first2, __last2);
1165
1166       using _RATag = random_access_iterator_tag;
1167       using _Cat1 = typename iterator_traits<_IIter1>::iterator_category;
1168       using _Cat2 = typename iterator_traits<_IIter2>::iterator_category;
1169       using _RAIters = __and_<is_same<_Cat1, _RATag>, is_same<_Cat2, _RATag>>;
1170       if (_RAIters())
1171         {
1172           auto __d1 = std::distance(__first1, __last1);
1173           auto __d2 = std::distance(__first2, __last2);
1174           if (__d1 != __d2)
1175             return false;
1176           return _GLIBCXX_STD_A::equal(__first1, __last1, __first2,
1177                                        __binary_pred);
1178         }
1179
1180       for (; __first1 != __last1 && __first2 != __last2;
1181           ++__first1, (void)++__first2)
1182         if (!bool(__binary_pred(*__first1, *__first2)))
1183           return false;
1184       return __first1 == __last1 && __first2 == __last2;
1185     }
1186 #endif
1187
1188   /**
1189    *  @brief Performs @b dictionary comparison on ranges.
1190    *  @ingroup sorting_algorithms
1191    *  @param  __first1  An input iterator.
1192    *  @param  __last1   An input iterator.
1193    *  @param  __first2  An input iterator.
1194    *  @param  __last2   An input iterator.
1195    *  @return   A boolean true or false.
1196    *
1197    *  <em>Returns true if the sequence of elements defined by the range
1198    *  [first1,last1) is lexicographically less than the sequence of elements
1199    *  defined by the range [first2,last2).  Returns false otherwise.</em>
1200    *  (Quoted from [25.3.8]/1.)  If the iterators are all character pointers,
1201    *  then this is an inline call to @c memcmp.
1202   */
1203   template<typename _II1, typename _II2>
1204     inline bool
1205     lexicographical_compare(_II1 __first1, _II1 __last1,
1206                             _II2 __first2, _II2 __last2)
1207     {
1208 #ifdef _GLIBCXX_CONCEPT_CHECKS
1209       // concept requirements
1210       typedef typename iterator_traits<_II1>::value_type _ValueType1;
1211       typedef typename iterator_traits<_II2>::value_type _ValueType2;
1212 #endif
1213       __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1214       __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1215       __glibcxx_function_requires(_LessThanOpConcept<_ValueType1, _ValueType2>)
1216       __glibcxx_function_requires(_LessThanOpConcept<_ValueType2, _ValueType1>)
1217       __glibcxx_requires_valid_range(__first1, __last1);
1218       __glibcxx_requires_valid_range(__first2, __last2);
1219
1220       return std::__lexicographical_compare_aux(std::__niter_base(__first1),
1221                                                 std::__niter_base(__last1),
1222                                                 std::__niter_base(__first2),
1223                                                 std::__niter_base(__last2));
1224     }
1225
1226   /**
1227    *  @brief Performs @b dictionary comparison on ranges.
1228    *  @ingroup sorting_algorithms
1229    *  @param  __first1  An input iterator.
1230    *  @param  __last1   An input iterator.
1231    *  @param  __first2  An input iterator.
1232    *  @param  __last2   An input iterator.
1233    *  @param  __comp  A @link comparison_functors comparison functor@endlink.
1234    *  @return   A boolean true or false.
1235    *
1236    *  The same as the four-parameter @c lexicographical_compare, but uses the
1237    *  comp parameter instead of @c <.
1238   */
1239   template<typename _II1, typename _II2, typename _Compare>
1240     inline bool
1241     lexicographical_compare(_II1 __first1, _II1 __last1,
1242                             _II2 __first2, _II2 __last2, _Compare __comp)
1243     {
1244       // concept requirements
1245       __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1246       __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1247       __glibcxx_requires_valid_range(__first1, __last1);
1248       __glibcxx_requires_valid_range(__first2, __last2);
1249
1250       return std::__lexicographical_compare_impl
1251         (__first1, __last1, __first2, __last2,
1252          __gnu_cxx::__ops::__iter_comp_iter(__comp));
1253     }
1254
1255   template<typename _InputIterator1, typename _InputIterator2,
1256            typename _BinaryPredicate>
1257     pair<_InputIterator1, _InputIterator2>
1258     __mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1259                _InputIterator2 __first2, _BinaryPredicate __binary_pred)
1260     {
1261       while (__first1 != __last1 && __binary_pred(__first1, __first2))
1262         {
1263           ++__first1;
1264           ++__first2;
1265         }
1266       return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
1267     }
1268
1269   /**
1270    *  @brief Finds the places in ranges which don't match.
1271    *  @ingroup non_mutating_algorithms
1272    *  @param  __first1  An input iterator.
1273    *  @param  __last1   An input iterator.
1274    *  @param  __first2  An input iterator.
1275    *  @return   A pair of iterators pointing to the first mismatch.
1276    *
1277    *  This compares the elements of two ranges using @c == and returns a pair
1278    *  of iterators.  The first iterator points into the first range, the
1279    *  second iterator points into the second range, and the elements pointed
1280    *  to by the iterators are not equal.
1281   */
1282   template<typename _InputIterator1, typename _InputIterator2>
1283     inline pair<_InputIterator1, _InputIterator2>
1284     mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1285              _InputIterator2 __first2)
1286     {
1287       // concept requirements
1288       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
1289       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
1290       __glibcxx_function_requires(_EqualOpConcept<
1291             typename iterator_traits<_InputIterator1>::value_type,
1292             typename iterator_traits<_InputIterator2>::value_type>)
1293       __glibcxx_requires_valid_range(__first1, __last1);
1294
1295       return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2,
1296                              __gnu_cxx::__ops::__iter_equal_to_iter());
1297     }
1298
1299   /**
1300    *  @brief Finds the places in ranges which don't match.
1301    *  @ingroup non_mutating_algorithms
1302    *  @param  __first1  An input iterator.
1303    *  @param  __last1   An input iterator.
1304    *  @param  __first2  An input iterator.
1305    *  @param __binary_pred A binary predicate @link functors
1306    *         functor@endlink.
1307    *  @return   A pair of iterators pointing to the first mismatch.
1308    *
1309    *  This compares the elements of two ranges using the binary_pred
1310    *  parameter, and returns a pair
1311    *  of iterators.  The first iterator points into the first range, the
1312    *  second iterator points into the second range, and the elements pointed
1313    *  to by the iterators are not equal.
1314   */
1315   template<typename _InputIterator1, typename _InputIterator2,
1316            typename _BinaryPredicate>
1317     inline pair<_InputIterator1, _InputIterator2>
1318     mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1319              _InputIterator2 __first2, _BinaryPredicate __binary_pred)
1320     {
1321       // concept requirements
1322       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
1323       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
1324       __glibcxx_requires_valid_range(__first1, __last1);
1325
1326       return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2,
1327         __gnu_cxx::__ops::__iter_comp_iter(__binary_pred));
1328     }
1329
1330 #if __cplusplus > 201103L
1331
1332   template<typename _InputIterator1, typename _InputIterator2,
1333            typename _BinaryPredicate>
1334     pair<_InputIterator1, _InputIterator2>
1335     __mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1336                _InputIterator2 __first2, _InputIterator2 __last2,
1337                _BinaryPredicate __binary_pred)
1338     {
1339       while (__first1 != __last1 && __first2 != __last2
1340              && __binary_pred(__first1, __first2))
1341         {
1342           ++__first1;
1343           ++__first2;
1344         }
1345       return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
1346     }
1347
1348   /**
1349    *  @brief Finds the places in ranges which don't match.
1350    *  @ingroup non_mutating_algorithms
1351    *  @param  __first1  An input iterator.
1352    *  @param  __last1   An input iterator.
1353    *  @param  __first2  An input iterator.
1354    *  @param  __last2   An input iterator.
1355    *  @return   A pair of iterators pointing to the first mismatch.
1356    *
1357    *  This compares the elements of two ranges using @c == and returns a pair
1358    *  of iterators.  The first iterator points into the first range, the
1359    *  second iterator points into the second range, and the elements pointed
1360    *  to by the iterators are not equal.
1361   */
1362   template<typename _InputIterator1, typename _InputIterator2>
1363     inline pair<_InputIterator1, _InputIterator2>
1364     mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1365              _InputIterator2 __first2, _InputIterator2 __last2)
1366     {
1367       // concept requirements
1368       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
1369       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
1370       __glibcxx_function_requires(_EqualOpConcept<
1371             typename iterator_traits<_InputIterator1>::value_type,
1372             typename iterator_traits<_InputIterator2>::value_type>)
1373       __glibcxx_requires_valid_range(__first1, __last1);
1374       __glibcxx_requires_valid_range(__first2, __last2);
1375
1376       return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2, __last2,
1377                              __gnu_cxx::__ops::__iter_equal_to_iter());
1378     }
1379
1380   /**
1381    *  @brief Finds the places in ranges which don't match.
1382    *  @ingroup non_mutating_algorithms
1383    *  @param  __first1  An input iterator.
1384    *  @param  __last1   An input iterator.
1385    *  @param  __first2  An input iterator.
1386    *  @param  __last2   An input iterator.
1387    *  @param __binary_pred A binary predicate @link functors
1388    *         functor@endlink.
1389    *  @return   A pair of iterators pointing to the first mismatch.
1390    *
1391    *  This compares the elements of two ranges using the binary_pred
1392    *  parameter, and returns a pair
1393    *  of iterators.  The first iterator points into the first range, the
1394    *  second iterator points into the second range, and the elements pointed
1395    *  to by the iterators are not equal.
1396   */
1397   template<typename _InputIterator1, typename _InputIterator2,
1398            typename _BinaryPredicate>
1399     inline pair<_InputIterator1, _InputIterator2>
1400     mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1401              _InputIterator2 __first2, _InputIterator2 __last2,
1402              _BinaryPredicate __binary_pred)
1403     {
1404       // concept requirements
1405       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
1406       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
1407       __glibcxx_requires_valid_range(__first1, __last1);
1408       __glibcxx_requires_valid_range(__first2, __last2);
1409
1410       return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2, __last2,
1411                              __gnu_cxx::__ops::__iter_comp_iter(__binary_pred));
1412     }
1413 #endif
1414
1415 _GLIBCXX_END_NAMESPACE_ALGO
1416 } // namespace std
1417
1418 // NB: This file is included within many other C++ includes, as a way
1419 // of getting the base algorithms. So, make sure that parallel bits
1420 // come in too if requested.
1421 #ifdef _GLIBCXX_PARALLEL
1422 # include <parallel/algobase.h>
1423 #endif
1424
1425 #endif