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

   1 /*
   2  *
   3  * Copyright (c) 1994
   4  * Hewlett-Packard Company
   5  *
   6  * Permission to use, copy, modify, distribute and sell this software
   7  * and its documentation for any purpose is hereby granted without fee,
   8  * provided that the above copyright notice appear in all copies and
   9  * that both that copyright notice and this permission notice appear
  10  * in supporting documentation.  Hewlett-Packard Company makes no
  11  * representations about the suitability of this software for any
  12  * purpose.  It is provided "as is" without express or implied warranty.
  13  *
  14  *
  15  * Copyright (c) 1996-1998
  16  * Silicon Graphics Computer Systems, Inc.
  17  *
  18  * Permission to use, copy, modify, distribute and sell this software
  19  * and its documentation for any purpose is hereby granted without fee,
  20  * provided that the above copyright notice appear in all copies and
  21  * that both that copyright notice and this permission notice appear
  22  * in supporting documentation.  Silicon Graphics makes no
  23  * representations about the suitability of this software for any
  24  * purpose.  It is provided "as is" without express or implied warranty.
  25  */
  26
  27 /* NOTE: This is an internal header file, included by other STL headers.
  28  *   You should not attempt to use it directly.
  29  */
  30
  31 #ifndef __SGI_STL_INTERNAL_ITERATOR_BASE_TYPES_H
  32 #define __SGI_STL_INTERNAL_ITERATOR_BASE_TYPES_H
  33
  34 // This file contains all of the general iterator-related utility
  35 // types, such as iterator_traits and struct iterator.
  36 // The internal file stl_iterator.h contains predefined iterators,
  37 // such as front_insert_iterator and istream_iterator.
  38
  39 #pragma GCC system header
  40
  41 namespace std
  42 {
  43
  44 struct input_iterator_tag {};
  45 struct output_iterator_tag {};
  46 struct forward_iterator_tag : public input_iterator_tag {};
  47 struct bidirectional_iterator_tag : public forward_iterator_tag {};
  48 struct random_access_iterator_tag : public bidirectional_iterator_tag {};
  49
  50 // The base classes input_iterator, output_iterator, forward_iterator,
  51 // bidirectional_iterator, and random_access_iterator are not part of
  52 // the C++ standard.  (They have been replaced by struct iterator.)
  53 // They are included for backward compatibility with the HP STL.
  54
  55 template <class _Tp, class _Distance> struct input_iterator {
  56   typedef input_iterator_tag iterator_category;
  57   typedef _Tp                value_type;
  58   typedef _Distance          difference_type;
  59   typedef _Tp*               pointer;
  60   typedef _Tp&               reference;
  61 };
  62
  63 struct output_iterator {
  64   typedef output_iterator_tag iterator_category;
  65   typedef void                value_type;
  66   typedef void                difference_type;
  67   typedef void                pointer;
  68   typedef void                reference;
  69 };
  70
  71 template <class _Tp, class _Distance> struct forward_iterator {
  72   typedef forward_iterator_tag iterator_category;
  73   typedef _Tp                  value_type;
  74   typedef _Distance            difference_type;
  75   typedef _Tp*                 pointer;
  76   typedef _Tp&                 reference;
  77 };
  78
  79
  80 template <class _Tp, class _Distance> struct bidirectional_iterator {
  81   typedef bidirectional_iterator_tag iterator_category;
  82   typedef _Tp                        value_type;
  83   typedef _Distance                  difference_type;
  84   typedef _Tp*                       pointer;
  85   typedef _Tp&                       reference;
  86 };
  87
  88 template <class _Tp, class _Distance> struct random_access_iterator {
  89   typedef random_access_iterator_tag iterator_category;
  90   typedef _Tp                        value_type;
  91   typedef _Distance                  difference_type;
  92   typedef _Tp*                       pointer;
  93   typedef _Tp&                       reference;
  94 };
  95
  96 template <class _Category, class _Tp, class _Distance = ptrdiff_t,
  97           class _Pointer = _Tp*, class _Reference = _Tp&>
  98 struct iterator {
  99   typedef _Category  iterator_category;
 100   typedef _Tp        value_type;
 101   typedef _Distance  difference_type;
 102   typedef _Pointer   pointer;
 103   typedef _Reference reference;
 104 };
 105
 106 template <class _Iterator>
 107 struct iterator_traits {
 108   typedef typename _Iterator::iterator_category iterator_category;
 109   typedef typename _Iterator::value_type        value_type;
 110   typedef typename _Iterator::difference_type   difference_type;
 111   typedef typename _Iterator::pointer           pointer;
 112   typedef typename _Iterator::reference         reference;
 113 };
 114
 115 template <class _Tp>
 116 struct iterator_traits<_Tp*> {
 117   typedef random_access_iterator_tag iterator_category;
 118   typedef _Tp                         value_type;
 119   typedef ptrdiff_t                   difference_type;
 120   typedef _Tp*                        pointer;
 121   typedef _Tp&                        reference;
 122 };
 123
 124 template <class _Tp>
 125 struct iterator_traits<const _Tp*> {
 126   typedef random_access_iterator_tag iterator_category;
 127   typedef _Tp                         value_type;
 128   typedef ptrdiff_t                   difference_type;
 129   typedef const _Tp*                  pointer;
 130   typedef const _Tp&                  reference;
 131 };
 132
 133 // The overloaded functions iterator_category, distance_type, and
 134 // value_type are not part of the C++ standard.  (They have been
 135 // replaced by struct iterator_traits.)  They are included for
 136 // backward compatibility with the HP STL.
 137
 138 // We introduce internal names for these functions.
 139
 140 template <class _Iter>
 141 inline typename iterator_traits<_Iter>::iterator_category
 142 __iterator_category(const _Iter&)
 143 {
 144   typedef typename iterator_traits<_Iter>::iterator_category _Category;
 145   return _Category();
 146 }
 147
 148 template <class _Iter>
 149 inline typename iterator_traits<_Iter>::difference_type*
 150 __distance_type(const _Iter&)
 151 {
 152   return static_cast<typename iterator_traits<_Iter>::difference_type*>(0);
 153 }
 154
 155 template <class _Iter>
 156 inline typename iterator_traits<_Iter>::value_type*
 157 __value_type(const _Iter&)
 158 {
 159   return static_cast<typename iterator_traits<_Iter>::value_type*>(0);
 160 }
 161
 162 template <class _Iter>
 163 inline typename iterator_traits<_Iter>::iterator_category
 164 iterator_category(const _Iter& __i) { return __iterator_category(__i); }
 165
 166
 167 template <class _Iter>
 168 inline typename iterator_traits<_Iter>::difference_type*
 169 distance_type(const _Iter& __i) { return __distance_type(__i); }
 170
 171 template <class _Iter>
 172 inline typename iterator_traits<_Iter>::value_type*
 173 value_type(const _Iter& __i) { return __value_type(__i); }
 174
 175 } // namespace std
 176
 177 #endif /* __SGI_STL_INTERNAL_ITERATOR_BASE_TYPES_H */
 178
 179
 180 // Local Variables:
 181 // mode:C++
 182 // End: