1 : // Types used in iterator implementation -*- C++ -*-
2 :
3 : // Copyright (C) 2001, 2002, 2004 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, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
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_types.h
57 : * This is an internal header file, included by other library headers.
58 : * You should not attempt to use it directly.
59 : *
60 : * This file contains all of the general iterator-related utility types,
61 : * such as iterator_traits and struct iterator.
62 : */
63 :
64 : #ifndef _ITERATOR_BASE_TYPES_H
65 : #define _ITERATOR_BASE_TYPES_H 1
66 :
67 : #pragma GCC system_header
68 :
69 : namespace std
70 : {
71 : //@{
72 : /**
73 : * @defgroup iterator_tags Iterator Tags
74 : * These are empty types, used to distinguish different iterators. The
75 : * distinction is not made by what they contain, but simply by what they
76 : * are. Different underlying algorithms can then be used based on the
77 : * different operations supporetd by different iterator types.
78 : */
79 : /// Marking input iterators.
80 : struct input_iterator_tag {};
81 : /// Marking output iterators.
82 : struct output_iterator_tag {};
83 : /// Forward iterators support a superset of input iterator operations.
84 : struct forward_iterator_tag : public input_iterator_tag {};
85 : /// Bidirectional iterators support a superset of forward iterator
86 : /// operations.
87 : struct bidirectional_iterator_tag : public forward_iterator_tag {};
88 : /// Random-access iterators support a superset of bidirectional iterator
89 : /// operations.
90 : struct random_access_iterator_tag : public bidirectional_iterator_tag {};
91 : //@}
92 :
93 :
94 : /**
95 : * @brief Common %iterator class.
96 : *
97 : * This class does nothing but define nested typedefs. %Iterator classes
98 : * can inherit from this class to save some work. The typedefs are then
99 : * used in specializations and overloading.
100 : *
101 : * In particular, there are no default implementations of requirements
102 : * such as @c operator++ and the like. (How could there be?)
103 : */
104 : template<typename _Category, typename _Tp, typename _Distance = ptrdiff_t,
105 : typename _Pointer = _Tp*, typename _Reference = _Tp&>
106 : struct iterator
107 892769 : {
108 : /// One of the @link iterator_tags tag types@endlink.
109 : typedef _Category iterator_category;
110 : /// The type "pointed to" by the iterator.
111 : typedef _Tp value_type;
112 : /// Distance between iterators is represented as this type.
113 : typedef _Distance difference_type;
114 : /// This type represents a pointer-to-value_type.
115 : typedef _Pointer pointer;
116 : /// This type represents a reference-to-value_type.
117 : typedef _Reference reference;
118 : };
119 :
120 : /**
121 : * This class does nothing but define nested typedefs. The general
122 : * version simply "forwards" the nested typedefs from the Iterator
123 : * argument. Specialized versions for pointers and pointers-to-const
124 : * provide tighter, more correct semantics.
125 : */
126 : template<typename _Iterator>
127 : struct iterator_traits
128 : {
129 : typedef typename _Iterator::iterator_category iterator_category;
130 : typedef typename _Iterator::value_type value_type;
131 : typedef typename _Iterator::difference_type difference_type;
132 : typedef typename _Iterator::pointer pointer;
133 : typedef typename _Iterator::reference reference;
134 : };
135 :
136 : template<typename _Tp>
137 : struct iterator_traits<_Tp*>
138 : {
139 : typedef random_access_iterator_tag iterator_category;
140 : typedef _Tp value_type;
141 : typedef ptrdiff_t difference_type;
142 : typedef _Tp* pointer;
143 : typedef _Tp& reference;
144 : };
145 :
146 : template<typename _Tp>
147 : struct iterator_traits<const _Tp*>
148 : {
149 : typedef random_access_iterator_tag iterator_category;
150 : typedef _Tp value_type;
151 : typedef ptrdiff_t difference_type;
152 : typedef const _Tp* pointer;
153 : typedef const _Tp& reference;
154 : };
155 :
156 : /**
157 : * @if maint
158 : * This function is not a part of the C++ standard but is syntactic
159 : * sugar for internal library use only.
160 : * @endif
161 : */
162 : template<typename _Iter>
163 : inline typename iterator_traits<_Iter>::iterator_category
164 300952 : __iterator_category(const _Iter&)
165 300952 : { return typename iterator_traits<_Iter>::iterator_category(); }
166 :
167 : } // namespace std
168 :
169 : #endif /* _ITERATOR_BASE_TYPES_H */
170 :
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