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       __builtin_memset(__first, static_cast<unsigned char>(__tmp),
 709                        __last - __first);
 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 (__first1 == 0 || __first2 == 0)
 816             return __first1 == __last1;
 817
 818           return !__builtin_memcmp(__first1, __first2, sizeof(_Tp)
 819                                    * (__last1 - __first1));
 820         }
 821     };
 822
 823   template<typename _II1, typename _II2>
 824     inline bool
 825     __equal_aux(_II1 __first1, _II1 __last1, _II2 __first2)
 826     {
 827       typedef typename iterator_traits<_II1>::value_type _ValueType1;
 828       typedef typename iterator_traits<_II2>::value_type _ValueType2;
 829       const bool __simple = ((__is_integer<_ValueType1>::__value
 830                               || __is_pointer<_ValueType1>::__value)
 831                              && __is_pointer<_II1>::__value
 832                              && __is_pointer<_II2>::__value
 833                              && __are_same<_ValueType1, _ValueType2>::__value);
 834
 835       return std::__equal<__simple>::equal(__first1, __last1, __first2);
 836     }
 837
 838   template<typename, typename>
 839     struct __lc_rai
 840     {
 841       template<typename _II1, typename _II2>
 842         static _II1
 843         __newlast1(_II1, _II1 __last1, _II2, _II2)
 844         { return __last1; }
 845
 846       template<typename _II>
 847         static bool
 848         __cnd2(_II __first, _II __last)
 849         { return __first != __last; }
 850     };
 851
 852   template<>
 853     struct __lc_rai<random_access_iterator_tag, random_access_iterator_tag>
 854     {
 855       template<typename _RAI1, typename _RAI2>
 856         static _RAI1
 857         __newlast1(_RAI1 __first1, _RAI1 __last1,
 858                    _RAI2 __first2, _RAI2 __last2)
 859         {
 860           const typename iterator_traits<_RAI1>::difference_type
 861             __diff1 = __last1 - __first1;
 862           const typename iterator_traits<_RAI2>::difference_type
 863             __diff2 = __last2 - __first2;
 864           return __diff2 < __diff1 ? __first1 + __diff2 : __last1;
 865         }
 866
 867       template<typename _RAI>
 868         static bool
 869         __cnd2(_RAI, _RAI)
 870         { return true; }
 871     };
 872
 873   template<typename _II1, typename _II2, typename _Compare>
 874     bool
 875     __lexicographical_compare_impl(_II1 __first1, _II1 __last1,
 876                                    _II2 __first2, _II2 __last2,
 877                                    _Compare __comp)
 878     {
 879       typedef typename iterator_traits<_II1>::iterator_category _Category1;
 880       typedef typename iterator_traits<_II2>::iterator_category _Category2;
 881       typedef std::__lc_rai<_Category1, _Category2> __rai_type;
 882
 883       __last1 = __rai_type::__newlast1(__first1, __last1, __first2, __last2);
 884       for (; __first1 != __last1 && __rai_type::__cnd2(__first2, __last2);
 885            ++__first1, (void)++__first2)
 886         {
 887           if (__comp(__first1, __first2))
 888             return true;
 889           if (__comp(__first2, __first1))
 890             return false;
 891         }
 892       return __first1 == __last1 && __first2 != __last2;
 893     }
 894
 895   template<bool _BoolType>
 896     struct __lexicographical_compare
 897     {
 898       template<typename _II1, typename _II2>
 899         static bool __lc(_II1, _II1, _II2, _II2);
 900     };
 901
 902   template<bool _BoolType>
 903     template<typename _II1, typename _II2>
 904       bool
 905       __lexicographical_compare<_BoolType>::
 906       __lc(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
 907       {
 908         return std::__lexicographical_compare_impl(__first1, __last1,
 909                                                    __first2, __last2,
 910                                         __gnu_cxx::__ops::__iter_less_iter());
 911       }
 912
 913   template<>
 914     struct __lexicographical_compare<true>
 915     {
 916       template<typename _Tp, typename _Up>
 917         static bool
 918         __lc(const _Tp* __first1, const _Tp* __last1,
 919              const _Up* __first2, const _Up* __last2)
 920         {
 921           const size_t __len1 = __last1 - __first1;
 922           const size_t __len2 = __last2 - __first2;
 923           if (__len1 && __len2)
 924             {
 925               if (int __result = __builtin_memcmp(__first1, __first2,
 926                                                   std::min(__len1, __len2)))
 927                 {
 928                   return __result < 0;
 929                 }
 930             }
 931           return __len1 < __len2;
 932         }
 933     };
 934
 935   template<typename _II1, typename _II2>
 936     inline bool
 937     __lexicographical_compare_aux(_II1 __first1, _II1 __last1,
 938                                   _II2 __first2, _II2 __last2)
 939     {
 940       typedef typename iterator_traits<_II1>::value_type _ValueType1;
 941       typedef typename iterator_traits<_II2>::value_type _ValueType2;
 942       const bool __simple =
 943         (__is_byte<_ValueType1>::__value && __is_byte<_ValueType2>::__value
 944          && !__gnu_cxx::__numeric_traits<_ValueType1>::__is_signed
 945          && !__gnu_cxx::__numeric_traits<_ValueType2>::__is_signed
 946          && __is_pointer<_II1>::__value
 947          && __is_pointer<_II2>::__value);
 948
 949       return std::__lexicographical_compare<__simple>::__lc(__first1, __last1,
 950                                                             __first2, __last2);
 951     }
 952
 953   template<typename _ForwardIterator, typename _Tp, typename _Compare>
 954     _ForwardIterator
 955     __lower_bound(_ForwardIterator __first, _ForwardIterator __last,
 956                   const _Tp& __val, _Compare __comp)
 957     {
 958       typedef typename iterator_traits<_ForwardIterator>::difference_type
 959         _DistanceType;
 960
 961       _DistanceType __len = std::distance(__first, __last);
 962
 963       while (__len > 0)
 964         {
 965           _DistanceType __half = __len >> 1;
 966           _ForwardIterator __middle = __first;
 967           std::advance(__middle, __half);
 968           if (__comp(__middle, __val))
 969             {
 970               __first = __middle;
 971               ++__first;
 972               __len = __len - __half - 1;
 973             }
 974           else
 975             __len = __half;
 976         }
 977       return __first;
 978     }
 979
 980   /**
 981    *  @brief Finds the first position in which @a val could be inserted
 982    *         without changing the ordering.
 983    *  @param  __first   An iterator.
 984    *  @param  __last    Another iterator.
 985    *  @param  __val     The search term.
 986    *  @return         An iterator pointing to the first element <em>not less
 987    *                  than</em> @a val, or end() if every element is less than
 988    *                  @a val.
 989    *  @ingroup binary_search_algorithms
 990   */
 991   template<typename _ForwardIterator, typename _Tp>
 992     inline _ForwardIterator
 993     lower_bound(_ForwardIterator __first, _ForwardIterator __last,
 994                 const _Tp& __val)
 995     {
 996       // concept requirements
 997       __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
 998       __glibcxx_function_requires(_LessThanOpConcept<
 999             typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
1000       __glibcxx_requires_partitioned_lower(__first, __last, __val);
1001
1002       return std::__lower_bound(__first, __last, __val,
1003                                 __gnu_cxx::__ops::__iter_less_val());
1004     }
1005
1006   /// This is a helper function for the sort routines and for random.tcc.
1007   //  Precondition: __n > 0.
1008   inline _GLIBCXX_CONSTEXPR int
1009   __lg(int __n)
1010   { return sizeof(int) * __CHAR_BIT__  - 1 - __builtin_clz(__n); }
1011
1012   inline _GLIBCXX_CONSTEXPR unsigned
1013   __lg(unsigned __n)
1014   { return sizeof(int) * __CHAR_BIT__  - 1 - __builtin_clz(__n); }
1015
1016   inline _GLIBCXX_CONSTEXPR long
1017   __lg(long __n)
1018   { return sizeof(long) * __CHAR_BIT__ - 1 - __builtin_clzl(__n); }
1019
1020   inline _GLIBCXX_CONSTEXPR unsigned long
1021   __lg(unsigned long __n)
1022   { return sizeof(long) * __CHAR_BIT__ - 1 - __builtin_clzl(__n); }
1023
1024   inline _GLIBCXX_CONSTEXPR long long
1025   __lg(long long __n)
1026   { return sizeof(long long) * __CHAR_BIT__ - 1 - __builtin_clzll(__n); }
1027
1028   inline _GLIBCXX_CONSTEXPR unsigned long long
1029   __lg(unsigned long long __n)
1030   { return sizeof(long long) * __CHAR_BIT__ - 1 - __builtin_clzll(__n); }
1031
1032 _GLIBCXX_END_NAMESPACE_VERSION
1033
1034 _GLIBCXX_BEGIN_NAMESPACE_ALGO
1035
1036   /**
1037    *  @brief Tests a range for element-wise equality.
1038    *  @ingroup non_mutating_algorithms
1039    *  @param  __first1  An input iterator.
1040    *  @param  __last1   An input iterator.
1041    *  @param  __first2  An input iterator.
1042    *  @return   A boolean true or false.
1043    *
1044    *  This compares the elements of two ranges using @c == and returns true or
1045    *  false depending on whether all of the corresponding elements of the
1046    *  ranges are equal.
1047   */
1048   template<typename _II1, typename _II2>
1049     inline bool
1050     equal(_II1 __first1, _II1 __last1, _II2 __first2)
1051     {
1052       // concept requirements
1053       __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1054       __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1055       __glibcxx_function_requires(_EqualOpConcept<
1056             typename iterator_traits<_II1>::value_type,
1057             typename iterator_traits<_II2>::value_type>)
1058       __glibcxx_requires_valid_range(__first1, __last1);
1059
1060       return std::__equal_aux(std::__niter_base(__first1),
1061                               std::__niter_base(__last1),
1062                               std::__niter_base(__first2));
1063     }
1064
1065   /**
1066    *  @brief Tests a range for element-wise equality.
1067    *  @ingroup non_mutating_algorithms
1068    *  @param  __first1  An input iterator.
1069    *  @param  __last1   An input iterator.
1070    *  @param  __first2  An input iterator.
1071    *  @param __binary_pred A binary predicate @link functors
1072    *                  functor@endlink.
1073    *  @return         A boolean true or false.
1074    *
1075    *  This compares the elements of two ranges using the binary_pred
1076    *  parameter, and returns true or
1077    *  false depending on whether all of the corresponding elements of the
1078    *  ranges are equal.
1079   */
1080   template<typename _IIter1, typename _IIter2, typename _BinaryPredicate>
1081     inline bool
1082     equal(_IIter1 __first1, _IIter1 __last1,
1083           _IIter2 __first2, _BinaryPredicate __binary_pred)
1084     {
1085       // concept requirements
1086       __glibcxx_function_requires(_InputIteratorConcept<_IIter1>)
1087       __glibcxx_function_requires(_InputIteratorConcept<_IIter2>)
1088       __glibcxx_requires_valid_range(__first1, __last1);
1089
1090       for (; __first1 != __last1; ++__first1, (void)++__first2)
1091         if (!bool(__binary_pred(*__first1, *__first2)))
1092           return false;
1093       return true;
1094     }
1095
1096 #if __cplusplus > 201103L
1097
1098 #define __cpp_lib_robust_nonmodifying_seq_ops 201304
1099
1100   /**
1101    *  @brief Tests a range for element-wise equality.
1102    *  @ingroup non_mutating_algorithms
1103    *  @param  __first1  An input iterator.
1104    *  @param  __last1   An input iterator.
1105    *  @param  __first2  An input iterator.
1106    *  @param  __last2   An input iterator.
1107    *  @return   A boolean true or false.
1108    *
1109    *  This compares the elements of two ranges using @c == and returns true or
1110    *  false depending on whether all of the corresponding elements of the
1111    *  ranges are equal.
1112   */
1113   template<typename _II1, typename _II2>
1114     inline bool
1115     equal(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
1116     {
1117       // concept requirements
1118       __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1119       __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1120       __glibcxx_function_requires(_EqualOpConcept<
1121             typename iterator_traits<_II1>::value_type,
1122             typename iterator_traits<_II2>::value_type>)
1123       __glibcxx_requires_valid_range(__first1, __last1);
1124       __glibcxx_requires_valid_range(__first2, __last2);
1125
1126       using _RATag = random_access_iterator_tag;
1127       using _Cat1 = typename iterator_traits<_II1>::iterator_category;
1128       using _Cat2 = typename iterator_traits<_II2>::iterator_category;
1129       using _RAIters = __and_<is_same<_Cat1, _RATag>, is_same<_Cat2, _RATag>>;
1130       if (_RAIters())
1131         {
1132           auto __d1 = std::distance(__first1, __last1);
1133           auto __d2 = std::distance(__first2, __last2);
1134           if (__d1 != __d2)
1135             return false;
1136           return _GLIBCXX_STD_A::equal(__first1, __last1, __first2);
1137         }
1138
1139       for (; __first1 != __last1 && __first2 != __last2;
1140           ++__first1, (void)++__first2)
1141         if (!(*__first1 == *__first2))
1142           return false;
1143       return __first1 == __last1 && __first2 == __last2;
1144     }
1145
1146   /**
1147    *  @brief Tests a range for element-wise equality.
1148    *  @ingroup non_mutating_algorithms
1149    *  @param  __first1  An input iterator.
1150    *  @param  __last1   An input iterator.
1151    *  @param  __first2  An input iterator.
1152    *  @param  __last2   An input iterator.
1153    *  @param __binary_pred A binary predicate @link functors
1154    *                  functor@endlink.
1155    *  @return         A boolean true or false.
1156    *
1157    *  This compares the elements of two ranges using the binary_pred
1158    *  parameter, and returns true or
1159    *  false depending on whether all of the corresponding elements of the
1160    *  ranges are equal.
1161   */
1162   template<typename _IIter1, typename _IIter2, typename _BinaryPredicate>
1163     inline bool
1164     equal(_IIter1 __first1, _IIter1 __last1,
1165           _IIter2 __first2, _IIter2 __last2, _BinaryPredicate __binary_pred)
1166     {
1167       // concept requirements
1168       __glibcxx_function_requires(_InputIteratorConcept<_IIter1>)
1169       __glibcxx_function_requires(_InputIteratorConcept<_IIter2>)
1170       __glibcxx_requires_valid_range(__first1, __last1);
1171       __glibcxx_requires_valid_range(__first2, __last2);
1172
1173       using _RATag = random_access_iterator_tag;
1174       using _Cat1 = typename iterator_traits<_IIter1>::iterator_category;
1175       using _Cat2 = typename iterator_traits<_IIter2>::iterator_category;
1176       using _RAIters = __and_<is_same<_Cat1, _RATag>, is_same<_Cat2, _RATag>>;
1177       if (_RAIters())
1178         {
1179           auto __d1 = std::distance(__first1, __last1);
1180           auto __d2 = std::distance(__first2, __last2);
1181           if (__d1 != __d2)
1182             return false;
1183           return _GLIBCXX_STD_A::equal(__first1, __last1, __first2,
1184                                        __binary_pred);
1185         }
1186
1187       for (; __first1 != __last1 && __first2 != __last2;
1188           ++__first1, (void)++__first2)
1189         if (!bool(__binary_pred(*__first1, *__first2)))
1190           return false;
1191       return __first1 == __last1 && __first2 == __last2;
1192     }
1193 #endif
1194
1195   /**
1196    *  @brief Performs @b dictionary comparison on ranges.
1197    *  @ingroup sorting_algorithms
1198    *  @param  __first1  An input iterator.
1199    *  @param  __last1   An input iterator.
1200    *  @param  __first2  An input iterator.
1201    *  @param  __last2   An input iterator.
1202    *  @return   A boolean true or false.
1203    *
1204    *  <em>Returns true if the sequence of elements defined by the range
1205    *  [first1,last1) is lexicographically less than the sequence of elements
1206    *  defined by the range [first2,last2).  Returns false otherwise.</em>
1207    *  (Quoted from [25.3.8]/1.)  If the iterators are all character pointers,
1208    *  then this is an inline call to @c memcmp.
1209   */
1210   template<typename _II1, typename _II2>
1211     inline bool
1212     lexicographical_compare(_II1 __first1, _II1 __last1,
1213                             _II2 __first2, _II2 __last2)
1214     {
1215 #ifdef _GLIBCXX_CONCEPT_CHECKS
1216       // concept requirements
1217       typedef typename iterator_traits<_II1>::value_type _ValueType1;
1218       typedef typename iterator_traits<_II2>::value_type _ValueType2;
1219 #endif
1220       __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1221       __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1222       __glibcxx_function_requires(_LessThanOpConcept<_ValueType1, _ValueType2>)
1223       __glibcxx_function_requires(_LessThanOpConcept<_ValueType2, _ValueType1>)
1224       __glibcxx_requires_valid_range(__first1, __last1);
1225       __glibcxx_requires_valid_range(__first2, __last2);
1226
1227       return std::__lexicographical_compare_aux(std::__niter_base(__first1),
1228                                                 std::__niter_base(__last1),
1229                                                 std::__niter_base(__first2),
1230                                                 std::__niter_base(__last2));
1231     }
1232
1233   /**
1234    *  @brief Performs @b dictionary comparison on ranges.
1235    *  @ingroup sorting_algorithms
1236    *  @param  __first1  An input iterator.
1237    *  @param  __last1   An input iterator.
1238    *  @param  __first2  An input iterator.
1239    *  @param  __last2   An input iterator.
1240    *  @param  __comp  A @link comparison_functors comparison functor@endlink.
1241    *  @return   A boolean true or false.
1242    *
1243    *  The same as the four-parameter @c lexicographical_compare, but uses the
1244    *  comp parameter instead of @c <.
1245   */
1246   template<typename _II1, typename _II2, typename _Compare>
1247     inline bool
1248     lexicographical_compare(_II1 __first1, _II1 __last1,
1249                             _II2 __first2, _II2 __last2, _Compare __comp)
1250     {
1251       // concept requirements
1252       __glibcxx_function_requires(_InputIteratorConcept<_II1>)
1253       __glibcxx_function_requires(_InputIteratorConcept<_II2>)
1254       __glibcxx_requires_valid_range(__first1, __last1);
1255       __glibcxx_requires_valid_range(__first2, __last2);
1256
1257       return std::__lexicographical_compare_impl
1258         (__first1, __last1, __first2, __last2,
1259          __gnu_cxx::__ops::__iter_comp_iter(__comp));
1260     }
1261
1262   template<typename _InputIterator1, typename _InputIterator2,
1263            typename _BinaryPredicate>
1264     pair<_InputIterator1, _InputIterator2>
1265     __mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1266                _InputIterator2 __first2, _BinaryPredicate __binary_pred)
1267     {
1268       while (__first1 != __last1 && __binary_pred(__first1, __first2))
1269         {
1270           ++__first1;
1271           ++__first2;
1272         }
1273       return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
1274     }
1275
1276   /**
1277    *  @brief Finds the places in ranges which don't match.
1278    *  @ingroup non_mutating_algorithms
1279    *  @param  __first1  An input iterator.
1280    *  @param  __last1   An input iterator.
1281    *  @param  __first2  An input iterator.
1282    *  @return   A pair of iterators pointing to the first mismatch.
1283    *
1284    *  This compares the elements of two ranges using @c == and returns a pair
1285    *  of iterators.  The first iterator points into the first range, the
1286    *  second iterator points into the second range, and the elements pointed
1287    *  to by the iterators are not equal.
1288   */
1289   template<typename _InputIterator1, typename _InputIterator2>
1290     inline pair<_InputIterator1, _InputIterator2>
1291     mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1292              _InputIterator2 __first2)
1293     {
1294       // concept requirements
1295       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
1296       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
1297       __glibcxx_function_requires(_EqualOpConcept<
1298             typename iterator_traits<_InputIterator1>::value_type,
1299             typename iterator_traits<_InputIterator2>::value_type>)
1300       __glibcxx_requires_valid_range(__first1, __last1);
1301
1302       return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2,
1303                              __gnu_cxx::__ops::__iter_equal_to_iter());
1304     }
1305
1306   /**
1307    *  @brief Finds the places in ranges which don't match.
1308    *  @ingroup non_mutating_algorithms
1309    *  @param  __first1  An input iterator.
1310    *  @param  __last1   An input iterator.
1311    *  @param  __first2  An input iterator.
1312    *  @param __binary_pred A binary predicate @link functors
1313    *         functor@endlink.
1314    *  @return   A pair of iterators pointing to the first mismatch.
1315    *
1316    *  This compares the elements of two ranges using the binary_pred
1317    *  parameter, and returns a pair
1318    *  of iterators.  The first iterator points into the first range, the
1319    *  second iterator points into the second range, and the elements pointed
1320    *  to by the iterators are not equal.
1321   */
1322   template<typename _InputIterator1, typename _InputIterator2,
1323            typename _BinaryPredicate>
1324     inline pair<_InputIterator1, _InputIterator2>
1325     mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1326              _InputIterator2 __first2, _BinaryPredicate __binary_pred)
1327     {
1328       // concept requirements
1329       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
1330       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
1331       __glibcxx_requires_valid_range(__first1, __last1);
1332
1333       return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2,
1334         __gnu_cxx::__ops::__iter_comp_iter(__binary_pred));
1335     }
1336
1337 #if __cplusplus > 201103L
1338
1339   template<typename _InputIterator1, typename _InputIterator2,
1340            typename _BinaryPredicate>
1341     pair<_InputIterator1, _InputIterator2>
1342     __mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1343                _InputIterator2 __first2, _InputIterator2 __last2,
1344                _BinaryPredicate __binary_pred)
1345     {
1346       while (__first1 != __last1 && __first2 != __last2
1347              && __binary_pred(__first1, __first2))
1348         {
1349           ++__first1;
1350           ++__first2;
1351         }
1352       return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
1353     }
1354
1355   /**
1356    *  @brief Finds the places in ranges which don't match.
1357    *  @ingroup non_mutating_algorithms
1358    *  @param  __first1  An input iterator.
1359    *  @param  __last1   An input iterator.
1360    *  @param  __first2  An input iterator.
1361    *  @param  __last2   An input iterator.
1362    *  @return   A pair of iterators pointing to the first mismatch.
1363    *
1364    *  This compares the elements of two ranges using @c == and returns a pair
1365    *  of iterators.  The first iterator points into the first range, the
1366    *  second iterator points into the second range, and the elements pointed
1367    *  to by the iterators are not equal.
1368   */
1369   template<typename _InputIterator1, typename _InputIterator2>
1370     inline pair<_InputIterator1, _InputIterator2>
1371     mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1372              _InputIterator2 __first2, _InputIterator2 __last2)
1373     {
1374       // concept requirements
1375       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
1376       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
1377       __glibcxx_function_requires(_EqualOpConcept<
1378             typename iterator_traits<_InputIterator1>::value_type,
1379             typename iterator_traits<_InputIterator2>::value_type>)
1380       __glibcxx_requires_valid_range(__first1, __last1);
1381       __glibcxx_requires_valid_range(__first2, __last2);
1382
1383       return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2, __last2,
1384                              __gnu_cxx::__ops::__iter_equal_to_iter());
1385     }
1386
1387   /**
1388    *  @brief Finds the places in ranges which don't match.
1389    *  @ingroup non_mutating_algorithms
1390    *  @param  __first1  An input iterator.
1391    *  @param  __last1   An input iterator.
1392    *  @param  __first2  An input iterator.
1393    *  @param  __last2   An input iterator.
1394    *  @param __binary_pred A binary predicate @link functors
1395    *         functor@endlink.
1396    *  @return   A pair of iterators pointing to the first mismatch.
1397    *
1398    *  This compares the elements of two ranges using the binary_pred
1399    *  parameter, and returns a pair
1400    *  of iterators.  The first iterator points into the first range, the
1401    *  second iterator points into the second range, and the elements pointed
1402    *  to by the iterators are not equal.
1403   */
1404   template<typename _InputIterator1, typename _InputIterator2,
1405            typename _BinaryPredicate>
1406     inline pair<_InputIterator1, _InputIterator2>
1407     mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1408              _InputIterator2 __first2, _InputIterator2 __last2,
1409              _BinaryPredicate __binary_pred)
1410     {
1411       // concept requirements
1412       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
1413       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
1414       __glibcxx_requires_valid_range(__first1, __last1);
1415       __glibcxx_requires_valid_range(__first2, __last2);
1416
1417       return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2, __last2,
1418                              __gnu_cxx::__ops::__iter_comp_iter(__binary_pred));
1419     }
1420 #endif
1421
1422 _GLIBCXX_END_NAMESPACE_ALGO
1423 } // namespace std
1424
1425 // NB: This file is included within many other C++ includes, as a way
1426 // of getting the base algorithms. So, make sure that parallel bits
1427 // come in too if requested.
1428 #ifdef _GLIBCXX_PARALLEL
1429 # include <parallel/algobase.h>
1430 #endif
1431
1432 #endif