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

   1 // Functions used by iterators -*- C++ -*-
   2
   3 // Copyright (C) 2001 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 2, 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 // You should have received a copy of the GNU General Public License along
  17 // with this library; see the file COPYING.  If not, write to the Free
  18 // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  19 // USA.
  20
  21 // As a special exception, you may use this file as part of a free software
  22 // library without restriction.  Specifically, if other files instantiate
  23 // templates or use macros or inline functions from this file, or you compile
  24 // this file and link it with other files to produce an executable, this
  25 // file does not by itself cause the resulting executable to be covered by
  26 // the GNU General Public License.  This exception does not however
  27 // invalidate any other reasons why the executable file might be covered by
  28 // the GNU General Public License.
  29
  30 /*
  31  *
  32  * Copyright (c) 1994
  33  * Hewlett-Packard Company
  34  *
  35  * Permission to use, copy, modify, distribute and sell this software
  36  * and its documentation for any purpose is hereby granted without fee,
  37  * provided that the above copyright notice appear in all copies and
  38  * that both that copyright notice and this permission notice appear
  39  * in supporting documentation.  Hewlett-Packard Company makes no
  40  * representations about the suitability of this software for any
  41  * purpose.  It is provided "as is" without express or implied warranty.
  42  *
  43  *
  44  * Copyright (c) 1996-1998
  45  * Silicon Graphics Computer Systems, Inc.
  46  *
  47  * Permission to use, copy, modify, distribute and sell this software
  48  * and its documentation for any purpose is hereby granted without fee,
  49  * provided that the above copyright notice appear in all copies and
  50  * that both that copyright notice and this permission notice appear
  51  * in supporting documentation.  Silicon Graphics makes no
  52  * representations about the suitability of this software for any
  53  * purpose.  It is provided "as is" without express or implied warranty.
  54  */
  55
  56 /** @file stl_iterator_base_funcs.h
  57  *  This is an internal header file, included by other library headers.
  58  *  You should not attempt to use it directly.
  59  */
  60
  61 #ifndef __GLIBCPP_INTERNAL_ITERATOR_BASE_FUNCS_H
  62 #define __GLIBCPP_INTERNAL_ITERATOR_BASE_FUNCS_H
  63
  64 // This file contains all of the general iterator-related utility
  65 // functions, such as distance() and advance().
  66 // The internal file stl_iterator.h contains predefined iterators,
  67 // such as front_insert_iterator and istream_iterator.
  68
  69 #pragma GCC system_header
  70 #include <bits/concept_check.h>
  71
  72 namespace std
  73 {
  74   template<typename _InputIterator>
  75     inline typename iterator_traits<_InputIterator>::difference_type
  76     __distance(_InputIterator __first, _InputIterator __last, input_iterator_tag)
  77     {
  78       // concept requirements
  79       __glibcpp_function_requires(_InputIteratorConcept<_InputIterator>)
  80       typename iterator_traits<_InputIterator>::difference_type __n = 0;
  81       while (__first != __last) {
  82         ++__first; ++__n;
  83       }
  84       return __n;
  85     }
  86
  87   template<typename _RandomAccessIterator>
  88     inline typename iterator_traits<_RandomAccessIterator>::difference_type
  89     __distance(_RandomAccessIterator __first, _RandomAccessIterator __last,
  90                            random_access_iterator_tag)
  91     {
  92       // concept requirements
  93       __glibcpp_function_requires(_RandomAccessIteratorConcept<_RandomAccessIterator>)
  94       return __last - __first;
  95     }
  96
  97   template<typename _InputIterator>
  98     inline typename iterator_traits<_InputIterator>::difference_type
  99     distance(_InputIterator __first, _InputIterator __last)
 100     {
 101       // concept requirements -- taken care of in __distance
 102       return __distance(__first, __last, __iterator_category(__first));
 103     }
 104
 105   template<typename _InputIter, typename _Distance>
 106     inline void
 107     __advance(_InputIter& __i, _Distance __n, input_iterator_tag)
 108     {
 109       // concept requirements
 110       __glibcpp_function_requires(_InputIteratorConcept<_InputIter>)
 111       while (__n--) ++__i;
 112     }
 113
 114   template<typename _BidirectionalIterator, typename _Distance>
 115     inline void
 116     __advance(_BidirectionalIterator& __i, _Distance __n, bidirectional_iterator_tag)
 117     {
 118       // concept requirements
 119       __glibcpp_function_requires(_BidirectionalIteratorConcept<_BidirectionalIterator>)
 120       if (__n > 0)
 121         while (__n--) ++__i;
 122       else
 123         while (__n++) --__i;
 124     }
 125
 126   template<typename _RandomAccessIterator, typename _Distance>
 127     inline void
 128     __advance(_RandomAccessIterator& __i, _Distance __n, random_access_iterator_tag)
 129     {
 130       // concept requirements
 131       __glibcpp_function_requires(_RandomAccessIteratorConcept<_RandomAccessIterator>)
 132       __i += __n;
 133     }
 134
 135   template<typename _InputIterator, typename _Distance>
 136     inline void
 137     advance(_InputIterator& __i, _Distance __n)
 138     {
 139       // concept requirements -- taken care of in __advance
 140       __advance(__i, __n, __iterator_category(__i));
 141     }
 142
 143 } // namespace std
 144
 145 #endif /* __GLIBCPP_INTERNAL_ITERATOR_BASE_FUNCS_H */
 146
 147
 148 // Local Variables:
 149 // mode:C++
 150 // End: