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 __SGI_STL_INTERNAL_ITERATOR_BASE_FUNCS_H
  62 #define __SGI_STL_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
  75   // There are two signatures for distance.  In addition to the one taking
  76   // two iterators and returning a result, there is another taking two
  77   // iterators and a reference-to-result variable, and returning nothing.
  78   // The latter seems to be an SGI extension.   -- pedwards
  79   template<typename _InputIterator, typename _Distance>
  80     inline void
  81     __distance(_InputIterator __first, _InputIterator __last,
  82                _Distance& __n, input_iterator_tag)
  83     {
  84       // concept requirements
  85       __glibcpp_function_requires(_InputIteratorConcept<_InputIterator>)
  86       while (__first != __last) { ++__first; ++__n; }
  87     }
  88
  89   template<typename _RandomAccessIterator, typename _Distance>
  90     inline void
  91     __distance(_RandomAccessIterator __first, _RandomAccessIterator __last,
  92                _Distance& __n, random_access_iterator_tag)
  93     {
  94       // concept requirements
  95       __glibcpp_function_requires(_RandomAccessIteratorConcept<_RandomAccessIterator>)
  96       __n += __last - __first;
  97     }
  98
  99   template<typename _InputIterator, typename _Distance>
 100     inline void
 101     distance(_InputIterator __first, _InputIterator __last,
 102              _Distance& __n)
 103     {
 104       // concept requirements -- taken care of in __distance
 105       __distance(__first, __last, __n, __iterator_category(__first));
 106     }
 107
 108   template<typename _InputIterator>
 109     inline typename iterator_traits<_InputIterator>::difference_type
 110     __distance(_InputIterator __first, _InputIterator __last, input_iterator_tag)
 111     {
 112       // concept requirements
 113       __glibcpp_function_requires(_InputIteratorConcept<_InputIterator>)
 114       typename iterator_traits<_InputIterator>::difference_type __n = 0;
 115       while (__first != __last) {
 116         ++__first; ++__n;
 117       }
 118       return __n;
 119     }
 120
 121   template<typename _RandomAccessIterator>
 122     inline typename iterator_traits<_RandomAccessIterator>::difference_type
 123     __distance(_RandomAccessIterator __first, _RandomAccessIterator __last,
 124                            random_access_iterator_tag)
 125     {
 126       // concept requirements
 127       __glibcpp_function_requires(_RandomAccessIteratorConcept<_RandomAccessIterator>)
 128       return __last - __first;
 129     }
 130
 131   template<typename _InputIterator>
 132     inline typename iterator_traits<_InputIterator>::difference_type
 133     distance(_InputIterator __first, _InputIterator __last)
 134     {
 135       // concept requirements -- taken care of in __distance
 136       return __distance(__first, __last, __iterator_category(__first));
 137     }
 138
 139   template<typename _InputIter, typename _Distance>
 140     inline void
 141     __advance(_InputIter& __i, _Distance __n, input_iterator_tag)
 142     {
 143       // concept requirements
 144       __glibcpp_function_requires(_InputIteratorConcept<_InputIter>)
 145       while (__n--) ++__i;
 146     }
 147
 148   template<typename _BidirectionalIterator, typename _Distance>
 149     inline void
 150     __advance(_BidirectionalIterator& __i, _Distance __n, bidirectional_iterator_tag)
 151     {
 152       // concept requirements
 153       __glibcpp_function_requires(_BidirectionalIteratorConcept<_BidirectionalIterator>)
 154       if (__n > 0)
 155         while (__n--) ++__i;
 156       else
 157         while (__n++) --__i;
 158     }
 159
 160   template<typename _RandomAccessIterator, typename _Distance>
 161     inline void
 162     __advance(_RandomAccessIterator& __i, _Distance __n, random_access_iterator_tag)
 163     {
 164       // concept requirements
 165       __glibcpp_function_requires(_RandomAccessIteratorConcept<_RandomAccessIterator>)
 166       __i += __n;
 167     }
 168
 169   template<typename _InputIterator, typename _Distance>
 170     inline void
 171     advance(_InputIterator& __i, _Distance __n)
 172     {
 173       // concept requirements -- taken care of in __advance
 174       __advance(__i, __n, __iterator_category(__i));
 175     }
 176
 177 } // namespace std
 178
 179 #endif /* __SGI_STL_INTERNAL_ITERATOR_BASE_FUNCS_H */
 180
 181
 182 // Local Variables:
 183 // mode:C++
 184 // End: