stl_algobase.h

Go to the documentation of this file.
00001 // Core algorithmic facilities -*- C++ -*-
00002 
00003 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
00004 // Free Software Foundation, Inc.
00005 //
00006 // This file is part of the GNU ISO C++ Library.  This library is free
00007 // software; you can redistribute it and/or modify it under the
00008 // terms of the GNU General Public License as published by the
00009 // Free Software Foundation; either version 3, or (at your option)
00010 // any later version.
00011 
00012 // This library is distributed in the hope that it will be useful,
00013 // but WITHOUT ANY WARRANTY; without even the implied warranty of
00014 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00015 // GNU General Public License for more details.
00016 
00017 // Under Section 7 of GPL version 3, you are granted additional
00018 // permissions described in the GCC Runtime Library Exception, version
00019 // 3.1, as published by the Free Software Foundation.
00020 
00021 // You should have received a copy of the GNU General Public License and
00022 // a copy of the GCC Runtime Library Exception along with this program;
00023 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
00024 // <http://www.gnu.org/licenses/>.
00025 
00026 /*
00027  *
00028  * Copyright (c) 1994
00029  * Hewlett-Packard Company
00030  *
00031  * Permission to use, copy, modify, distribute and sell this software
00032  * and its documentation for any purpose is hereby granted without fee,
00033  * provided that the above copyright notice appear in all copies and
00034  * that both that copyright notice and this permission notice appear
00035  * in supporting documentation.  Hewlett-Packard Company makes no
00036  * representations about the suitability of this software for any
00037  * purpose.  It is provided "as is" without express or implied warranty.
00038  *
00039  *
00040  * Copyright (c) 1996-1998
00041  * Silicon Graphics Computer Systems, Inc.
00042  *
00043  * Permission to use, copy, modify, distribute and sell this software
00044  * and its documentation for any purpose is hereby granted without fee,
00045  * provided that the above copyright notice appear in all copies and
00046  * that both that copyright notice and this permission notice appear
00047  * in supporting documentation.  Silicon Graphics makes no
00048  * representations about the suitability of this software for any
00049  * purpose.  It is provided "as is" without express or implied warranty.
00050  */
00051 
00052 /** @file stl_algobase.h
00053  *  This is an internal header file, included by other library headers.
00054  *  You should not attempt to use it directly.
00055  */
00056 
00057 #ifndef _STL_ALGOBASE_H
00058 #define _STL_ALGOBASE_H 1
00059 
00060 #include <bits/c++config.h>
00061 #include <cstddef>
00062 #include <bits/functexcept.h>
00063 #include <bits/cpp_type_traits.h>
00064 #include <ext/type_traits.h>
00065 #include <ext/numeric_traits.h>
00066 #include <bits/stl_pair.h>
00067 #include <bits/stl_iterator_base_types.h>
00068 #include <bits/stl_iterator_base_funcs.h>
00069 #include <bits/stl_iterator.h>
00070 #include <bits/concept_check.h>
00071 #include <debug/debug.h>
00072 #include <bits/move.h> // For std::swap and _GLIBCXX_MOVE
00073 
00074 _GLIBCXX_BEGIN_NAMESPACE(std)
00075 
00076   // See http://gcc.gnu.org/ml/libstdc++/2004-08/msg00167.html: in a
00077   // nutshell, we are partially implementing the resolution of DR 187,
00078   // when it's safe, i.e., the value_types are equal.
00079   template<bool _BoolType>
00080     struct __iter_swap
00081     {
00082       template<typename _ForwardIterator1, typename _ForwardIterator2>
00083         static void
00084         iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
00085         {
00086           typedef typename iterator_traits<_ForwardIterator1>::value_type
00087             _ValueType1;
00088           _ValueType1 __tmp = _GLIBCXX_MOVE(*__a);
00089           *__a = _GLIBCXX_MOVE(*__b);
00090           *__b = _GLIBCXX_MOVE(__tmp);
00091     }
00092     };
00093 
00094   template<>
00095     struct __iter_swap<true>
00096     {
00097       template<typename _ForwardIterator1, typename _ForwardIterator2>
00098         static void 
00099         iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
00100         {
00101           swap(*__a, *__b);
00102         }
00103     };
00104 
00105   /**
00106    *  @brief Swaps the contents of two iterators.
00107    *  @ingroup mutating_algorithms
00108    *  @param  a  An iterator.
00109    *  @param  b  Another iterator.
00110    *  @return   Nothing.
00111    *
00112    *  This function swaps the values pointed to by two iterators, not the
00113    *  iterators themselves.
00114   */
00115   template<typename _ForwardIterator1, typename _ForwardIterator2>
00116     inline void
00117     iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
00118     {
00119       typedef typename iterator_traits<_ForwardIterator1>::value_type
00120     _ValueType1;
00121       typedef typename iterator_traits<_ForwardIterator2>::value_type
00122     _ValueType2;
00123 
00124       // concept requirements
00125       __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
00126                   _ForwardIterator1>)
00127       __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
00128                   _ForwardIterator2>)
00129       __glibcxx_function_requires(_ConvertibleConcept<_ValueType1,
00130                   _ValueType2>)
00131       __glibcxx_function_requires(_ConvertibleConcept<_ValueType2,
00132                   _ValueType1>)
00133 
00134       typedef typename iterator_traits<_ForwardIterator1>::reference
00135     _ReferenceType1;
00136       typedef typename iterator_traits<_ForwardIterator2>::reference
00137     _ReferenceType2;
00138       std::__iter_swap<__are_same<_ValueType1, _ValueType2>::__value
00139     && __are_same<_ValueType1&, _ReferenceType1>::__value
00140     && __are_same<_ValueType2&, _ReferenceType2>::__value>::
00141 	iter_swap(__a, __b);
00142     }
00143 
00144   /**
00145    *  @brief Swap the elements of two sequences.
00146    *  @ingroup mutating_algorithms
00147    *  @param  first1  A forward iterator.
00148    *  @param  last1   A forward iterator.
00149    *  @param  first2  A forward iterator.
00150    *  @return   An iterator equal to @p first2+(last1-first1).
00151    *
00152    *  Swaps each element in the range @p [first1,last1) with the
00153    *  corresponding element in the range @p [first2,(last1-first1)).
00154    *  The ranges must not overlap.
00155   */
00156   template<typename _ForwardIterator1, typename _ForwardIterator2>
00157     _ForwardIterator2
00158     swap_ranges(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
00159         _ForwardIterator2 __first2)
00160     {
00161       // concept requirements
00162       __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
00163                   _ForwardIterator1>)
00164       __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
00165                   _ForwardIterator2>)
00166       __glibcxx_requires_valid_range(__first1, __last1);
00167 
00168       for (; __first1 != __last1; ++__first1, ++__first2)
00169     std::iter_swap(__first1, __first2);
00170       return __first2;
00171     }
00172 
00173   /**
00174    *  @brief This does what you think it does.
00175    *  @ingroup sorting_algorithms
00176    *  @param  a  A thing of arbitrary type.
00177    *  @param  b  Another thing of arbitrary type.
00178    *  @return   The lesser of the parameters.
00179    *
00180    *  This is the simple classic generic implementation.  It will work on
00181    *  temporary expressions, since they are only evaluated once, unlike a
00182    *  preprocessor macro.
00183   */
00184   template<typename _Tp>
00185     inline const _Tp&
00186     min(const _Tp& __a, const _Tp& __b)
00187     {
00188       // concept requirements
00189       __glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
00190       //return __b < __a ? __b : __a;
00191       if (__b < __a)
00192     return __b;
00193       return __a;
00194     }
00195 
00196   /**
00197    *  @brief This does what you think it does.
00198    *  @ingroup sorting_algorithms
00199    *  @param  a  A thing of arbitrary type.
00200    *  @param  b  Another thing of arbitrary type.
00201    *  @return   The greater of the parameters.
00202    *
00203    *  This is the simple classic generic implementation.  It will work on
00204    *  temporary expressions, since they are only evaluated once, unlike a
00205    *  preprocessor macro.
00206   */
00207   template<typename _Tp>
00208     inline const _Tp&
00209     max(const _Tp& __a, const _Tp& __b)
00210     {
00211       // concept requirements
00212       __glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
00213       //return  __a < __b ? __b : __a;
00214       if (__a < __b)
00215     return __b;
00216       return __a;
00217     }
00218 
00219   /**
00220    *  @brief This does what you think it does.
00221    *  @ingroup sorting_algorithms
00222    *  @param  a  A thing of arbitrary type.
00223    *  @param  b  Another thing of arbitrary type.
00224    *  @param  comp  A @link comparison_functors comparison functor@endlink.
00225    *  @return   The lesser of the parameters.
00226    *
00227    *  This will work on temporary expressions, since they are only evaluated
00228    *  once, unlike a preprocessor macro.
00229   */
00230   template<typename _Tp, typename _Compare>
00231     inline const _Tp&
00232     min(const _Tp& __a, const _Tp& __b, _Compare __comp)
00233     {
00234       //return __comp(__b, __a) ? __b : __a;
00235       if (__comp(__b, __a))
00236     return __b;
00237       return __a;
00238     }
00239 
00240   /**
00241    *  @brief This does what you think it does.
00242    *  @ingroup sorting_algorithms
00243    *  @param  a  A thing of arbitrary type.
00244    *  @param  b  Another thing of arbitrary type.
00245    *  @param  comp  A @link comparison_functors comparison functor@endlink.
00246    *  @return   The greater of the parameters.
00247    *
00248    *  This will work on temporary expressions, since they are only evaluated
00249    *  once, unlike a preprocessor macro.
00250   */
00251   template<typename _Tp, typename _Compare>
00252     inline const _Tp&
00253     max(const _Tp& __a, const _Tp& __b, _Compare __comp)
00254     {
00255       //return __comp(__a, __b) ? __b : __a;
00256       if (__comp(__a, __b))
00257     return __b;
00258       return __a;
00259     }
00260 
00261 
00262   // If _Iterator is a __normal_iterator return its base (a plain pointer,
00263   // normally) otherwise return it untouched.  See copy, fill, ... 
00264   template<typename _Iterator,
00265        bool _IsNormal = __is_normal_iterator<_Iterator>::__value>
00266     struct __niter_base
00267     {
00268       static _Iterator
00269       __b(_Iterator __it)
00270       { return __it; }
00271     };
00272 
00273   template<typename _Iterator>
00274     struct __niter_base<_Iterator, true>
00275     {
00276       static typename _Iterator::iterator_type
00277       __b(_Iterator __it)
00278       { return __it.base(); }
00279     };
00280 
00281   // Likewise, for move_iterator.
00282   template<typename _Iterator,
00283        bool _IsMove = __is_move_iterator<_Iterator>::__value>
00284     struct __miter_base
00285     {
00286       static _Iterator
00287       __b(_Iterator __it)
00288       { return __it; }
00289     };
00290 
00291   template<typename _Iterator>
00292     struct __miter_base<_Iterator, true>
00293     {
00294       static typename _Iterator::iterator_type
00295       __b(_Iterator __it)
00296       { return __it.base(); }
00297     };
00298 
00299   // All of these auxiliary structs serve two purposes.  (1) Replace
00300   // calls to copy with memmove whenever possible.  (Memmove, not memcpy,
00301   // because the input and output ranges are permitted to overlap.)
00302   // (2) If we're using random access iterators, then write the loop as
00303   // a for loop with an explicit count.
00304 
00305   template<bool, bool, typename>
00306     struct __copy_move
00307     {
00308       template<typename _II, typename _OI>
00309         static _OI
00310         __copy_m(_II __first, _II __last, _OI __result)
00311         {
00312       for (; __first != __last; ++__result, ++__first)
00313         *__result = *__first;
00314       return __result;
00315     }
00316     };
00317 
00318 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00319   template<typename _Category>
00320     struct __copy_move<true, false, _Category>
00321     {
00322       template<typename _II, typename _OI>
00323         static _OI
00324         __copy_m(_II __first, _II __last, _OI __result)
00325         {
00326       for (; __first != __last; ++__result, ++__first)
00327         *__result = std::move(*__first);
00328       return __result;
00329     }
00330     };
00331 #endif
00332 
00333   template<>
00334     struct __copy_move<false, false, random_access_iterator_tag>
00335     {
00336       template<typename _II, typename _OI>
00337         static _OI
00338         __copy_m(_II __first, _II __last, _OI __result)
00339         { 
00340       typedef typename iterator_traits<_II>::difference_type _Distance;
00341       for(_Distance __n = __last - __first; __n > 0; --__n)
00342         {
00343           *__result = *__first;
00344           ++__first;
00345           ++__result;
00346         }
00347       return __result;
00348     }
00349     };
00350 
00351 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00352   template<>
00353     struct __copy_move<true, false, random_access_iterator_tag>
00354     {
00355       template<typename _II, typename _OI>
00356         static _OI
00357         __copy_m(_II __first, _II __last, _OI __result)
00358         { 
00359       typedef typename iterator_traits<_II>::difference_type _Distance;
00360       for(_Distance __n = __last - __first; __n > 0; --__n)
00361         {
00362           *__result = std::move(*__first);
00363           ++__first;
00364           ++__result;
00365         }
00366       return __result;
00367     }
00368     };
00369 #endif
00370 
00371   template<bool _IsMove>
00372     struct __copy_move<_IsMove, true, random_access_iterator_tag>
00373     {
00374       template<typename _Tp>
00375         static _Tp*
00376         __copy_m(const _Tp* __first, const _Tp* __last, _Tp* __result)
00377         {
00378       __builtin_memmove(__result, __first,
00379                 sizeof(_Tp) * (__last - __first));
00380       return __result + (__last - __first);
00381     }
00382     };
00383 
00384   template<bool _IsMove, typename _II, typename _OI>
00385     inline _OI
00386     __copy_move_a(_II __first, _II __last, _OI __result)
00387     {
00388       typedef typename iterator_traits<_II>::value_type _ValueTypeI;
00389       typedef typename iterator_traits<_OI>::value_type _ValueTypeO;
00390       typedef typename iterator_traits<_II>::iterator_category _Category;
00391       const bool __simple = (__is_pod(_ValueTypeI)
00392                          && __is_pointer<_II>::__value
00393                          && __is_pointer<_OI>::__value
00394                  && __are_same<_ValueTypeI, _ValueTypeO>::__value);
00395 
00396       return std::__copy_move<_IsMove, __simple,
00397                           _Category>::__copy_m(__first, __last, __result);
00398     }
00399 
00400   // Helpers for streambuf iterators (either istream or ostream).
00401   // NB: avoid including <iosfwd>, relatively large.
00402   template<typename _CharT>
00403     struct char_traits;
00404 
00405   template<typename _CharT, typename _Traits>
00406     class istreambuf_iterator;
00407 
00408   template<typename _CharT, typename _Traits>
00409     class ostreambuf_iterator;
00410 
00411   template<bool _IsMove, typename _CharT>
00412     typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value, 
00413          ostreambuf_iterator<_CharT, char_traits<_CharT> > >::__type
00414     __copy_move_a2(_CharT*, _CharT*,
00415            ostreambuf_iterator<_CharT, char_traits<_CharT> >);
00416 
00417   template<bool _IsMove, typename _CharT>
00418     typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value, 
00419          ostreambuf_iterator<_CharT, char_traits<_CharT> > >::__type
00420     __copy_move_a2(const _CharT*, const _CharT*,
00421            ostreambuf_iterator<_CharT, char_traits<_CharT> >);
00422 
00423   template<bool _IsMove, typename _CharT>
00424     typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
00425                     _CharT*>::__type
00426     __copy_move_a2(istreambuf_iterator<_CharT, char_traits<_CharT> >,
00427            istreambuf_iterator<_CharT, char_traits<_CharT> >, _CharT*);
00428 
00429   template<bool _IsMove, typename _II, typename _OI>
00430     inline _OI
00431     __copy_move_a2(_II __first, _II __last, _OI __result)
00432     {
00433       return _OI(std::__copy_move_a<_IsMove>
00434          (std::__niter_base<_II>::__b(__first),
00435           std::__niter_base<_II>::__b(__last),
00436           std::__niter_base<_OI>::__b(__result)));
00437     }
00438 
00439   /**
00440    *  @brief Copies the range [first,last) into result.
00441    *  @ingroup mutating_algorithms
00442    *  @param  first  An input iterator.
00443    *  @param  last   An input iterator.
00444    *  @param  result An output iterator.
00445    *  @return   result + (first - last)
00446    *
00447    *  This inline function will boil down to a call to @c memmove whenever
00448    *  possible.  Failing that, if random access iterators are passed, then the
00449    *  loop count will be known (and therefore a candidate for compiler
00450    *  optimizations such as unrolling).  Result may not be contained within
00451    *  [first,last); the copy_backward function should be used instead.
00452    *
00453    *  Note that the end of the output range is permitted to be contained
00454    *  within [first,last).
00455   */
00456   template<typename _II, typename _OI>
00457     inline _OI
00458     copy(_II __first, _II __last, _OI __result)
00459     {
00460       // concept requirements
00461       __glibcxx_function_requires(_InputIteratorConcept<_II>)
00462       __glibcxx_function_requires(_OutputIteratorConcept<_OI,
00463         typename iterator_traits<_II>::value_type>)
00464       __glibcxx_requires_valid_range(__first, __last);
00465 
00466       return (std::__copy_move_a2<__is_move_iterator<_II>::__value>
00467           (std::__miter_base<_II>::__b(__first),
00468            std::__miter_base<_II>::__b(__last), __result));
00469     }
00470 
00471 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00472   /**
00473    *  @brief Moves the range [first,last) into result.
00474    *  @ingroup mutating_algorithms
00475    *  @param  first  An input iterator.
00476    *  @param  last   An input iterator.
00477    *  @param  result An output iterator.
00478    *  @return   result + (first - last)
00479    *
00480    *  This inline function will boil down to a call to @c memmove whenever
00481    *  possible.  Failing that, if random access iterators are passed, then the
00482    *  loop count will be known (and therefore a candidate for compiler
00483    *  optimizations such as unrolling).  Result may not be contained within
00484    *  [first,last); the move_backward function should be used instead.
00485    *
00486    *  Note that the end of the output range is permitted to be contained
00487    *  within [first,last).
00488   */
00489   template<typename _II, typename _OI>
00490     inline _OI
00491     move(_II __first, _II __last, _OI __result)
00492     {
00493       // concept requirements
00494       __glibcxx_function_requires(_InputIteratorConcept<_II>)
00495       __glibcxx_function_requires(_OutputIteratorConcept<_OI,
00496         typename iterator_traits<_II>::value_type>)
00497       __glibcxx_requires_valid_range(__first, __last);
00498 
00499       return (std::__copy_move_a2<true>
00500           (std::__miter_base<_II>::__b(__first),
00501            std::__miter_base<_II>::__b(__last), __result));
00502     }
00503 
00504 #define _GLIBCXX_MOVE3(_Tp, _Up, _Vp) std::move(_Tp, _Up, _Vp)
00505 #else
00506 #define _GLIBCXX_MOVE3(_Tp, _Up, _Vp) std::copy(_Tp, _Up, _Vp)
00507 #endif
00508 
00509   template<bool, bool, typename>
00510     struct __copy_move_backward
00511     {
00512       template<typename _BI1, typename _BI2>
00513         static _BI2
00514         __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
00515         {
00516       while (__first != __last)
00517         *--__result = *--__last;
00518       return __result;
00519     }
00520     };
00521 
00522 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00523   template<typename _Category>
00524     struct __copy_move_backward<true, false, _Category>
00525     {
00526       template<typename _BI1, typename _BI2>
00527         static _BI2
00528         __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
00529         {
00530       while (__first != __last)
00531         *--__result = std::move(*--__last);
00532       return __result;
00533     }
00534     };
00535 #endif
00536 
00537   template<>
00538     struct __copy_move_backward<false, false, random_access_iterator_tag>
00539     {
00540       template<typename _BI1, typename _BI2>
00541         static _BI2
00542         __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
00543         {
00544       typename iterator_traits<_BI1>::difference_type __n;
00545       for (__n = __last - __first; __n > 0; --__n)
00546         *--__result = *--__last;
00547       return __result;
00548     }
00549     };
00550 
00551 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00552   template<>
00553     struct __copy_move_backward<true, false, random_access_iterator_tag>
00554     {
00555       template<typename _BI1, typename _BI2>
00556         static _BI2
00557         __copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
00558         {
00559       typename iterator_traits<_BI1>::difference_type __n;
00560       for (__n = __last - __first; __n > 0; --__n)
00561         *--__result = std::move(*--__last);
00562       return __result;
00563     }
00564     };
00565 #endif
00566 
00567   template<bool _IsMove>
00568     struct __copy_move_backward<_IsMove, true, random_access_iterator_tag>
00569     {
00570       template<typename _Tp>
00571         static _Tp*
00572         __copy_move_b(const _Tp* __first, const _Tp* __last, _Tp* __result)
00573         {
00574       const ptrdiff_t _Num = __last - __first;
00575       __builtin_memmove(__result - _Num, __first, sizeof(_Tp) * _Num);
00576       return __result - _Num;
00577     }
00578     };
00579 
00580   template<bool _IsMove, typename _BI1, typename _BI2>
00581     inline _BI2
00582     __copy_move_backward_a(_BI1 __first, _BI1 __last, _BI2 __result)
00583     {
00584       typedef typename iterator_traits<_BI1>::value_type _ValueType1;
00585       typedef typename iterator_traits<_BI2>::value_type _ValueType2;
00586       typedef typename iterator_traits<_BI1>::iterator_category _Category;
00587       const bool __simple = (__is_pod(_ValueType1)
00588                          && __is_pointer<_BI1>::__value
00589                          && __is_pointer<_BI2>::__value
00590                  && __are_same<_ValueType1, _ValueType2>::__value);
00591 
00592       return std::__copy_move_backward<_IsMove, __simple,
00593                                    _Category>::__copy_move_b(__first,
00594                                  __last,
00595                                  __result);
00596     }
00597 
00598   template<bool _IsMove, typename _BI1, typename _BI2>
00599     inline _BI2
00600     __copy_move_backward_a2(_BI1 __first, _BI1 __last, _BI2 __result)
00601     {
00602       return _BI2(std::__copy_move_backward_a<_IsMove>
00603           (std::__niter_base<_BI1>::__b(__first),
00604            std::__niter_base<_BI1>::__b(__last),
00605            std::__niter_base<_BI2>::__b(__result)));
00606     }
00607 
00608   /**
00609    *  @brief Copies the range [first,last) into result.
00610    *  @ingroup mutating_algorithms
00611    *  @param  first  A bidirectional iterator.
00612    *  @param  last   A bidirectional iterator.
00613    *  @param  result A bidirectional iterator.
00614    *  @return   result - (first - last)
00615    *
00616    *  The function has the same effect as copy, but starts at the end of the
00617    *  range and works its way to the start, returning the start of the result.
00618    *  This inline function will boil down to a call to @c memmove whenever
00619    *  possible.  Failing that, if random access iterators are passed, then the
00620    *  loop count will be known (and therefore a candidate for compiler
00621    *  optimizations such as unrolling).
00622    *
00623    *  Result may not be in the range [first,last).  Use copy instead.  Note
00624    *  that the start of the output range may overlap [first,last).
00625   */
00626   template<typename _BI1, typename _BI2>
00627     inline _BI2
00628     copy_backward(_BI1 __first, _BI1 __last, _BI2 __result)
00629     {
00630       // concept requirements
00631       __glibcxx_function_requires(_BidirectionalIteratorConcept<_BI1>)
00632       __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<_BI2>)
00633       __glibcxx_function_requires(_ConvertibleConcept<
00634         typename iterator_traits<_BI1>::value_type,
00635         typename iterator_traits<_BI2>::value_type>)
00636       __glibcxx_requires_valid_range(__first, __last);
00637 
00638       return (std::__copy_move_backward_a2<__is_move_iterator<_BI1>::__value>
00639           (std::__miter_base<_BI1>::__b(__first),
00640            std::__miter_base<_BI1>::__b(__last), __result));
00641     }
00642 
00643 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00644   /**
00645    *  @brief Moves the range [first,last) into result.
00646    *  @ingroup mutating_algorithms
00647    *  @param  first  A bidirectional iterator.
00648    *  @param  last   A bidirectional iterator.
00649    *  @param  result A bidirectional iterator.
00650    *  @return   result - (first - last)
00651    *
00652    *  The function has the same effect as move, but starts at the end of the
00653    *  range and works its way to the start, returning the start of the result.
00654    *  This inline function will boil down to a call to @c memmove whenever
00655    *  possible.  Failing that, if random access iterators are passed, then the
00656    *  loop count will be known (and therefore a candidate for compiler
00657    *  optimizations such as unrolling).
00658    *
00659    *  Result may not be in the range [first,last).  Use move instead.  Note
00660    *  that the start of the output range may overlap [first,last).
00661   */
00662   template<typename _BI1, typename _BI2>
00663     inline _BI2
00664     move_backward(_BI1 __first, _BI1 __last, _BI2 __result)
00665     {
00666       // concept requirements
00667       __glibcxx_function_requires(_BidirectionalIteratorConcept<_BI1>)
00668       __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<_BI2>)
00669       __glibcxx_function_requires(_ConvertibleConcept<
00670         typename iterator_traits<_BI1>::value_type,
00671         typename iterator_traits<_BI2>::value_type>)
00672       __glibcxx_requires_valid_range(__first, __last);
00673 
00674       return (std::__copy_move_backward_a2<true>
00675           (std::__miter_base<_BI1>::__b(__first),
00676            std::__miter_base<_BI1>::__b(__last), __result));
00677     }
00678 
00679 #define _GLIBCXX_MOVE_BACKWARD3(_Tp, _Up, _Vp) std::move_backward(_Tp, _Up, _Vp)
00680 #else
00681 #define _GLIBCXX_MOVE_BACKWARD3(_Tp, _Up, _Vp) std::copy_backward(_Tp, _Up, _Vp)
00682 #endif
00683 
00684   template<typename _ForwardIterator, typename _Tp>
00685     inline typename
00686     __gnu_cxx::__enable_if<!__is_scalar<_Tp>::__value, void>::__type
00687     __fill_a(_ForwardIterator __first, _ForwardIterator __last,
00688          const _Tp& __value)
00689     {
00690       for (; __first != __last; ++__first)
00691     *__first = __value;
00692     }
00693     
00694   template<typename _ForwardIterator, typename _Tp>
00695     inline typename
00696     __gnu_cxx::__enable_if<__is_scalar<_Tp>::__value, void>::__type
00697     __fill_a(_ForwardIterator __first, _ForwardIterator __last,
00698          const _Tp& __value)
00699     {
00700       const _Tp __tmp = __value;
00701       for (; __first != __last; ++__first)
00702     *__first = __tmp;
00703     }
00704 
00705   // Specialization: for char types we can use memset.
00706   template<typename _Tp>
00707     inline typename
00708     __gnu_cxx::__enable_if<__is_byte<_Tp>::__value, void>::__type
00709     __fill_a(_Tp* __first, _Tp* __last, const _Tp& __c)
00710     {
00711       const _Tp __tmp = __c;
00712       __builtin_memset(__first, static_cast<unsigned char>(__tmp),
00713                __last - __first);
00714     }
00715 
00716   /**
00717    *  @brief Fills the range [first,last) with copies of value.
00718    *  @ingroup mutating_algorithms
00719    *  @param  first  A forward iterator.
00720    *  @param  last   A forward iterator.
00721    *  @param  value  A reference-to-const of arbitrary type.
00722    *  @return   Nothing.
00723    *
00724    *  This function fills a range with copies of the same value.  For char
00725    *  types filling contiguous areas of memory, this becomes an inline call
00726    *  to @c memset or @c wmemset.
00727   */
00728   template<typename _ForwardIterator, typename _Tp>
00729     inline void
00730     fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value)
00731     {
00732       // concept requirements
00733       __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
00734                   _ForwardIterator>)
00735       __glibcxx_requires_valid_range(__first, __last);
00736 
00737       std::__fill_a(std::__niter_base<_ForwardIterator>::__b(__first),
00738             std::__niter_base<_ForwardIterator>::__b(__last), __value);
00739     }
00740 
00741   template<typename _OutputIterator, typename _Size, typename _Tp>
00742     inline typename
00743     __gnu_cxx::__enable_if<!__is_scalar<_Tp>::__value, _OutputIterator>::__type
00744     __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value)
00745     {
00746       for (; __n > 0; --__n, ++__first)
00747     *__first = __value;
00748       return __first;
00749     }
00750 
00751   template<typename _OutputIterator, typename _Size, typename _Tp>
00752     inline typename
00753     __gnu_cxx::__enable_if<__is_scalar<_Tp>::__value, _OutputIterator>::__type
00754     __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value)
00755     {
00756       const _Tp __tmp = __value;
00757       for (; __n > 0; --__n, ++__first)
00758     *__first = __tmp;
00759       return __first;
00760     }
00761 
00762   template<typename _Size, typename _Tp>
00763     inline typename
00764     __gnu_cxx::__enable_if<__is_byte<_Tp>::__value, _Tp*>::__type
00765     __fill_n_a(_Tp* __first, _Size __n, const _Tp& __c)
00766     {
00767       std::__fill_a(__first, __first + __n, __c);
00768       return __first + __n;
00769     }
00770 
00771   /**
00772    *  @brief Fills the range [first,first+n) with copies of value.
00773    *  @ingroup mutating_algorithms
00774    *  @param  first  An output iterator.
00775    *  @param  n      The count of copies to perform.
00776    *  @param  value  A reference-to-const of arbitrary type.
00777    *  @return   The iterator at first+n.
00778    *
00779    *  This function fills a range with copies of the same value.  For char
00780    *  types filling contiguous areas of memory, this becomes an inline call
00781    *  to @c memset or @ wmemset.
00782   */
00783   template<typename _OI, typename _Size, typename _Tp>
00784     inline _OI
00785     fill_n(_OI __first, _Size __n, const _Tp& __value)
00786     {
00787       // concept requirements
00788       __glibcxx_function_requires(_OutputIteratorConcept<_OI, _Tp>)
00789 
00790       return _OI(std::__fill_n_a(std::__niter_base<_OI>::__b(__first),
00791                  __n, __value));
00792     }
00793 
00794   template<bool _BoolType>
00795     struct __equal
00796     {
00797       template<typename _II1, typename _II2>
00798         static bool
00799         equal(_II1 __first1, _II1 __last1, _II2 __first2)
00800         {
00801       for (; __first1 != __last1; ++__first1, ++__first2)
00802         if (!(*__first1 == *__first2))
00803           return false;
00804       return true;
00805     }
00806     };
00807 
00808   template<>
00809     struct __equal<true>
00810     {
00811       template<typename _Tp>
00812         static bool
00813         equal(const _Tp* __first1, const _Tp* __last1, const _Tp* __first2)
00814         {
00815       return !__builtin_memcmp(__first1, __first2, sizeof(_Tp)
00816                    * (__last1 - __first1));
00817     }
00818     };
00819 
00820   template<typename _II1, typename _II2>
00821     inline bool
00822     __equal_aux(_II1 __first1, _II1 __last1, _II2 __first2)
00823     {
00824       typedef typename iterator_traits<_II1>::value_type _ValueType1;
00825       typedef typename iterator_traits<_II2>::value_type _ValueType2;
00826       const bool __simple = (__is_integer<_ValueType1>::__value
00827                          && __is_pointer<_II1>::__value
00828                          && __is_pointer<_II2>::__value
00829                  && __are_same<_ValueType1, _ValueType2>::__value);
00830 
00831       return std::__equal<__simple>::equal(__first1, __last1, __first2);
00832     }
00833 
00834 
00835   template<typename, typename>
00836     struct __lc_rai
00837     {
00838       template<typename _II1, typename _II2>
00839         static _II1
00840         __newlast1(_II1, _II1 __last1, _II2, _II2)
00841         { return __last1; }
00842 
00843       template<typename _II>
00844         static bool
00845         __cnd2(_II __first, _II __last)
00846         { return __first != __last; }
00847     };
00848 
00849   template<>
00850     struct __lc_rai<random_access_iterator_tag, random_access_iterator_tag>
00851     {
00852       template<typename _RAI1, typename _RAI2>
00853         static _RAI1
00854         __newlast1(_RAI1 __first1, _RAI1 __last1,
00855            _RAI2 __first2, _RAI2 __last2)
00856         {
00857       const typename iterator_traits<_RAI1>::difference_type
00858         __diff1 = __last1 - __first1;
00859       const typename iterator_traits<_RAI2>::difference_type
00860         __diff2 = __last2 - __first2;
00861       return __diff2 < __diff1 ? __first1 + __diff2 : __last1;
00862     }
00863 
00864       template<typename _RAI>
00865         static bool
00866         __cnd2(_RAI, _RAI)
00867         { return true; }
00868     };
00869 
00870   template<bool _BoolType>
00871     struct __lexicographical_compare
00872     {
00873       template<typename _II1, typename _II2>
00874         static bool __lc(_II1, _II1, _II2, _II2);
00875     };
00876 
00877   template<bool _BoolType>
00878     template<typename _II1, typename _II2>
00879       bool
00880       __lexicographical_compare<_BoolType>::
00881       __lc(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
00882       {
00883     typedef typename iterator_traits<_II1>::iterator_category _Category1;
00884     typedef typename iterator_traits<_II2>::iterator_category _Category2;
00885     typedef std::__lc_rai<_Category1, _Category2>   __rai_type;
00886     
00887     __last1 = __rai_type::__newlast1(__first1, __last1,
00888                      __first2, __last2);
00889     for (; __first1 != __last1 && __rai_type::__cnd2(__first2, __last2);
00890          ++__first1, ++__first2)
00891       {
00892         if (*__first1 < *__first2)
00893           return true;
00894         if (*__first2 < *__first1)
00895           return false;
00896       }
00897     return __first1 == __last1 && __first2 != __last2;
00898       }
00899 
00900   template<>
00901     struct __lexicographical_compare<true>
00902     {
00903       template<typename _Tp, typename _Up>
00904         static bool
00905         __lc(const _Tp* __first1, const _Tp* __last1,
00906          const _Up* __first2, const _Up* __last2)
00907     {
00908       const size_t __len1 = __last1 - __first1;
00909       const size_t __len2 = __last2 - __first2;
00910       const int __result = __builtin_memcmp(__first1, __first2,
00911                         std::min(__len1, __len2));
00912       return __result != 0 ? __result < 0 : __len1 < __len2;
00913     }
00914     };
00915 
00916   template<typename _II1, typename _II2>
00917     inline bool
00918     __lexicographical_compare_aux(_II1 __first1, _II1 __last1,
00919                   _II2 __first2, _II2 __last2)
00920     {
00921       typedef typename iterator_traits<_II1>::value_type _ValueType1;
00922       typedef typename iterator_traits<_II2>::value_type _ValueType2;
00923       const bool __simple =
00924     (__is_byte<_ValueType1>::__value && __is_byte<_ValueType2>::__value
00925      && !__gnu_cxx::__numeric_traits<_ValueType1>::__is_signed
00926      && !__gnu_cxx::__numeric_traits<_ValueType2>::__is_signed
00927      && __is_pointer<_II1>::__value
00928      && __is_pointer<_II2>::__value);
00929 
00930       return std::__lexicographical_compare<__simple>::__lc(__first1, __last1,
00931                                 __first2, __last2);
00932     }
00933 
00934 _GLIBCXX_END_NAMESPACE
00935 
00936 _GLIBCXX_BEGIN_NESTED_NAMESPACE(std, _GLIBCXX_STD_P)
00937 
00938   /**
00939    *  @brief Tests a range for element-wise equality.
00940    *  @ingroup non_mutating_algorithms
00941    *  @param  first1  An input iterator.
00942    *  @param  last1   An input iterator.
00943    *  @param  first2  An input iterator.
00944    *  @return   A boolean true or false.
00945    *
00946    *  This compares the elements of two ranges using @c == and returns true or
00947    *  false depending on whether all of the corresponding elements of the
00948    *  ranges are equal.
00949   */
00950   template<typename _II1, typename _II2>
00951     inline bool
00952     equal(_II1 __first1, _II1 __last1, _II2 __first2)
00953     {
00954       // concept requirements
00955       __glibcxx_function_requires(_InputIteratorConcept<_II1>)
00956       __glibcxx_function_requires(_InputIteratorConcept<_II2>)
00957       __glibcxx_function_requires(_EqualOpConcept<
00958         typename iterator_traits<_II1>::value_type,
00959         typename iterator_traits<_II2>::value_type>)
00960       __glibcxx_requires_valid_range(__first1, __last1);
00961 
00962       return std::__equal_aux(std::__niter_base<_II1>::__b(__first1),
00963                   std::__niter_base<_II1>::__b(__last1),
00964                   std::__niter_base<_II2>::__b(__first2));
00965     }
00966 
00967   /**
00968    *  @brief Tests a range for element-wise equality.
00969    *  @ingroup non_mutating_algorithms
00970    *  @param  first1  An input iterator.
00971    *  @param  last1   An input iterator.
00972    *  @param  first2  An input iterator.
00973    *  @param binary_pred A binary predicate @link functors
00974    *                  functor@endlink.
00975    *  @return         A boolean true or false.
00976    *
00977    *  This compares the elements of two ranges using the binary_pred
00978    *  parameter, and returns true or
00979    *  false depending on whether all of the corresponding elements of the
00980    *  ranges are equal.
00981   */
00982   template<typename _IIter1, typename _IIter2, typename _BinaryPredicate>
00983     inline bool
00984     equal(_IIter1 __first1, _IIter1 __last1,
00985       _IIter2 __first2, _BinaryPredicate __binary_pred)
00986     {
00987       // concept requirements
00988       __glibcxx_function_requires(_InputIteratorConcept<_IIter1>)
00989       __glibcxx_function_requires(_InputIteratorConcept<_IIter2>)
00990       __glibcxx_requires_valid_range(__first1, __last1);
00991 
00992       for (; __first1 != __last1; ++__first1, ++__first2)
00993     if (!bool(__binary_pred(*__first1, *__first2)))
00994       return false;
00995       return true;
00996     }
00997 
00998   /**
00999    *  @brief Performs "dictionary" comparison on ranges.
01000    *  @ingroup sorting_algorithms
01001    *  @param  first1  An input iterator.
01002    *  @param  last1   An input iterator.
01003    *  @param  first2  An input iterator.
01004    *  @param  last2   An input iterator.
01005    *  @return   A boolean true or false.
01006    *
01007    *  "Returns true if the sequence of elements defined by the range
01008    *  [first1,last1) is lexicographically less than the sequence of elements
01009    *  defined by the range [first2,last2).  Returns false otherwise."
01010    *  (Quoted from [25.3.8]/1.)  If the iterators are all character pointers,
01011    *  then this is an inline call to @c memcmp.
01012   */
01013   template<typename _II1, typename _II2>
01014     inline bool
01015     lexicographical_compare(_II1 __first1, _II1 __last1,
01016                 _II2 __first2, _II2 __last2)
01017     {
01018       // concept requirements
01019       typedef typename iterator_traits<_II1>::value_type _ValueType1;
01020       typedef typename iterator_traits<_II2>::value_type _ValueType2;
01021       __glibcxx_function_requires(_InputIteratorConcept<_II1>)
01022       __glibcxx_function_requires(_InputIteratorConcept<_II2>)
01023       __glibcxx_function_requires(_LessThanOpConcept<_ValueType1, _ValueType2>)
01024       __glibcxx_function_requires(_LessThanOpConcept<_ValueType2, _ValueType1>)
01025       __glibcxx_requires_valid_range(__first1, __last1);
01026       __glibcxx_requires_valid_range(__first2, __last2);
01027 
01028       return std::__lexicographical_compare_aux
01029     (std::__niter_base<_II1>::__b(__first1),
01030      std::__niter_base<_II1>::__b(__last1),
01031      std::__niter_base<_II2>::__b(__first2),
01032      std::__niter_base<_II2>::__b(__last2));
01033     }
01034 
01035   /**
01036    *  @brief Performs "dictionary" comparison on ranges.
01037    *  @ingroup sorting_algorithms
01038    *  @param  first1  An input iterator.
01039    *  @param  last1   An input iterator.
01040    *  @param  first2  An input iterator.
01041    *  @param  last2   An input iterator.
01042    *  @param  comp  A @link comparison_functors comparison functor@endlink.
01043    *  @return   A boolean true or false.
01044    *
01045    *  The same as the four-parameter @c lexicographical_compare, but uses the
01046    *  comp parameter instead of @c <.
01047   */
01048   template<typename _II1, typename _II2, typename _Compare>
01049     bool
01050     lexicographical_compare(_II1 __first1, _II1 __last1,
01051                 _II2 __first2, _II2 __last2, _Compare __comp)
01052     {
01053       typedef typename iterator_traits<_II1>::iterator_category _Category1;
01054       typedef typename iterator_traits<_II2>::iterator_category _Category2;
01055       typedef std::__lc_rai<_Category1, _Category2>     __rai_type;
01056 
01057       // concept requirements
01058       __glibcxx_function_requires(_InputIteratorConcept<_II1>)
01059       __glibcxx_function_requires(_InputIteratorConcept<_II2>)
01060       __glibcxx_requires_valid_range(__first1, __last1);
01061       __glibcxx_requires_valid_range(__first2, __last2);
01062 
01063       __last1 = __rai_type::__newlast1(__first1, __last1, __first2, __last2);
01064       for (; __first1 != __last1 && __rai_type::__cnd2(__first2, __last2);
01065        ++__first1, ++__first2)
01066     {
01067       if (__comp(*__first1, *__first2))
01068         return true;
01069       if (__comp(*__first2, *__first1))
01070         return false;
01071     }
01072       return __first1 == __last1 && __first2 != __last2;
01073     }
01074 
01075   /**
01076    *  @brief Finds the places in ranges which don't match.
01077    *  @ingroup non_mutating_algorithms
01078    *  @param  first1  An input iterator.
01079    *  @param  last1   An input iterator.
01080    *  @param  first2  An input iterator.
01081    *  @return   A pair of iterators pointing to the first mismatch.
01082    *
01083    *  This compares the elements of two ranges using @c == and returns a pair
01084    *  of iterators.  The first iterator points into the first range, the
01085    *  second iterator points into the second range, and the elements pointed
01086    *  to by the iterators are not equal.
01087   */
01088   template<typename _InputIterator1, typename _InputIterator2>
01089     pair<_InputIterator1, _InputIterator2>
01090     mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
01091          _InputIterator2 __first2)
01092     {
01093       // concept requirements
01094       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
01095       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
01096       __glibcxx_function_requires(_EqualOpConcept<
01097         typename iterator_traits<_InputIterator1>::value_type,
01098         typename iterator_traits<_InputIterator2>::value_type>)
01099       __glibcxx_requires_valid_range(__first1, __last1);
01100 
01101       while (__first1 != __last1 && *__first1 == *__first2)
01102         {
01103       ++__first1;
01104       ++__first2;
01105         }
01106       return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
01107     }
01108 
01109   /**
01110    *  @brief Finds the places in ranges which don't match.
01111    *  @ingroup non_mutating_algorithms
01112    *  @param  first1  An input iterator.
01113    *  @param  last1   An input iterator.
01114    *  @param  first2  An input iterator.
01115    *  @param binary_pred A binary predicate @link functors
01116    *         functor@endlink.
01117    *  @return   A pair of iterators pointing to the first mismatch.
01118    *
01119    *  This compares the elements of two ranges using the binary_pred
01120    *  parameter, and returns a pair
01121    *  of iterators.  The first iterator points into the first range, the
01122    *  second iterator points into the second range, and the elements pointed
01123    *  to by the iterators are not equal.
01124   */
01125   template<typename _InputIterator1, typename _InputIterator2,
01126        typename _BinaryPredicate>
01127     pair<_InputIterator1, _InputIterator2>
01128     mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
01129          _InputIterator2 __first2, _BinaryPredicate __binary_pred)
01130     {
01131       // concept requirements
01132       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
01133       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
01134       __glibcxx_requires_valid_range(__first1, __last1);
01135 
01136       while (__first1 != __last1 && bool(__binary_pred(*__first1, *__first2)))
01137         {
01138       ++__first1;
01139       ++__first2;
01140         }
01141       return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
01142     }
01143 
01144 _GLIBCXX_END_NESTED_NAMESPACE
01145 
01146 // NB: This file is included within many other C++ includes, as a way
01147 // of getting the base algorithms. So, make sure that parallel bits
01148 // come in too if requested. 
01149 #ifdef _GLIBCXX_PARALLEL
01150 # include <parallel/algobase.h>
01151 #endif
01152 
01153 #endif

Generated on Thu Jul 23 21:16:19 2009 for libstdc++ by  doxygen 1.5.8