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

   1 // Types used in iterator implementation -*- 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 /* NOTE: This is an internal header file, included by other STL headers.
  57  *   You should not attempt to use it directly.
  58  */
  59
  60 #ifndef __SGI_STL_INTERNAL_ITERATOR_BASE_TYPES_H
  61 #define __SGI_STL_INTERNAL_ITERATOR_BASE_TYPES_H
  62
  63 // This file contains all of the general iterator-related utility
  64 // types, such as iterator_traits and struct iterator.
  65 // The internal file stl_iterator.h contains predefined iterators,
  66 // such as front_insert_iterator and istream_iterator.
  67
  68 #pragma GCC system_header
  69
  70 #include <bits/std_cstddef.h>     // for ptrdiff_t
  71
  72
  73 namespace std
  74 {
  75
  76 struct input_iterator_tag {};
  77 struct output_iterator_tag {};
  78 struct forward_iterator_tag : public input_iterator_tag {};
  79 struct bidirectional_iterator_tag : public forward_iterator_tag {};
  80 struct random_access_iterator_tag : public bidirectional_iterator_tag {};
  81
  82 // The base classes input_iterator, output_iterator, forward_iterator,
  83 // bidirectional_iterator, and random_access_iterator are not part of
  84 // the C++ standard.  (They have been replaced by struct iterator.)
  85 // They are included for backward compatibility with the HP STL.
  86
  87 template <class _Tp, class _Distance> struct input_iterator {
  88   typedef input_iterator_tag iterator_category;
  89   typedef _Tp                value_type;
  90   typedef _Distance          difference_type;
  91   typedef _Tp*               pointer;
  92   typedef _Tp&               reference;
  93 };
  94
  95 struct output_iterator {
  96   typedef output_iterator_tag iterator_category;
  97   typedef void                value_type;
  98   typedef void                difference_type;
  99   typedef void                pointer;
 100   typedef void                reference;
 101 };
 102
 103 template <class _Tp, class _Distance> struct forward_iterator {
 104   typedef forward_iterator_tag iterator_category;
 105   typedef _Tp                  value_type;
 106   typedef _Distance            difference_type;
 107   typedef _Tp*                 pointer;
 108   typedef _Tp&                 reference;
 109 };
 110
 111
 112 template <class _Tp, class _Distance> struct bidirectional_iterator {
 113   typedef bidirectional_iterator_tag iterator_category;
 114   typedef _Tp                        value_type;
 115   typedef _Distance                  difference_type;
 116   typedef _Tp*                       pointer;
 117   typedef _Tp&                       reference;
 118 };
 119
 120 template <class _Tp, class _Distance> struct random_access_iterator {
 121   typedef random_access_iterator_tag iterator_category;
 122   typedef _Tp                        value_type;
 123   typedef _Distance                  difference_type;
 124   typedef _Tp*                       pointer;
 125   typedef _Tp&                       reference;
 126 };
 127
 128 template <class _Category, class _Tp, class _Distance = ptrdiff_t,
 129           class _Pointer = _Tp*, class _Reference = _Tp&>
 130 struct iterator {
 131   typedef _Category  iterator_category;
 132   typedef _Tp        value_type;
 133   typedef _Distance  difference_type;
 134   typedef _Pointer   pointer;
 135   typedef _Reference reference;
 136 };
 137
 138 template <class _Iterator>
 139 struct iterator_traits {
 140   typedef typename _Iterator::iterator_category iterator_category;
 141   typedef typename _Iterator::value_type        value_type;
 142   typedef typename _Iterator::difference_type   difference_type;
 143   typedef typename _Iterator::pointer           pointer;
 144   typedef typename _Iterator::reference         reference;
 145 };
 146
 147 template <class _Tp>
 148 struct iterator_traits<_Tp*> {
 149   typedef random_access_iterator_tag iterator_category;
 150   typedef _Tp                         value_type;
 151   typedef ptrdiff_t                   difference_type;
 152   typedef _Tp*                        pointer;
 153   typedef _Tp&                        reference;
 154 };
 155
 156 template <class _Tp>
 157 struct iterator_traits<const _Tp*> {
 158   typedef random_access_iterator_tag iterator_category;
 159   typedef _Tp                         value_type;
 160   typedef ptrdiff_t                   difference_type;
 161   typedef const _Tp*                  pointer;
 162   typedef const _Tp&                  reference;
 163 };
 164
 165 // The overloaded functions iterator_category, distance_type, and
 166 // value_type are not part of the C++ standard.  (They have been
 167 // replaced by struct iterator_traits.)  They are included for
 168 // backward compatibility with the HP STL.
 169
 170 // We introduce internal names for these functions.
 171
 172 template <class _Iter>
 173 inline typename iterator_traits<_Iter>::iterator_category
 174 __iterator_category(const _Iter&)
 175 {
 176   typedef typename iterator_traits<_Iter>::iterator_category _Category;
 177   return _Category();
 178 }
 179
 180 template <class _Iter>
 181 inline typename iterator_traits<_Iter>::difference_type*
 182 __distance_type(const _Iter&)
 183 {
 184   return static_cast<typename iterator_traits<_Iter>::difference_type*>(0);
 185 }
 186
 187 template <class _Iter>
 188 inline typename iterator_traits<_Iter>::value_type*
 189 __value_type(const _Iter&)
 190 {
 191   return static_cast<typename iterator_traits<_Iter>::value_type*>(0);
 192 }
 193
 194 template <class _Iter>
 195 inline typename iterator_traits<_Iter>::iterator_category
 196 iterator_category(const _Iter& __i) { return __iterator_category(__i); }
 197
 198
 199 template <class _Iter>
 200 inline typename iterator_traits<_Iter>::difference_type*
 201 distance_type(const _Iter& __i) { return __distance_type(__i); }
 202
 203 template <class _Iter>
 204 inline typename iterator_traits<_Iter>::value_type*
 205 value_type(const _Iter& __i) { return __value_type(__i); }
 206
 207 } // namespace std
 208
 209 #endif /* __SGI_STL_INTERNAL_ITERATOR_BASE_TYPES_H */
 210
 211
 212 // Local Variables:
 213 // mode:C++
 214 // End: