1 : // Types used in iterator implementation -*- C++ -*-
2 :
3 : // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
4 : // Free Software Foundation, Inc.
5 : //
6 : // This file is part of the GNU ISO C++ Library. This library is free
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8 : // terms of the GNU General Public License as published by the
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10 : // any later version.
11 :
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14 : // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 : // GNU General Public License for more details.
16 :
17 : // You should have received a copy of the GNU General Public License along
18 : // with this library; see the file COPYING. If not, write to the Free
19 : // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
20 : // USA.
21 :
22 : // As a special exception, you may use this file as part of a free software
23 : // library without restriction. Specifically, if other files instantiate
24 : // templates or use macros or inline functions from this file, or you compile
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26 : // file does not by itself cause the resulting executable to be covered by
27 : // the GNU General Public License. This exception does not however
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29 : // the GNU General Public License.
30 :
31 : /*
32 : *
33 : * Copyright (c) 1994
34 : * Hewlett-Packard Company
35 : *
36 : * Permission to use, copy, modify, distribute and sell this software
37 : * and its documentation for any purpose is hereby granted without fee,
38 : * provided that the above copyright notice appear in all copies and
39 : * that both that copyright notice and this permission notice appear
40 : * in supporting documentation. Hewlett-Packard Company makes no
41 : * representations about the suitability of this software for any
42 : * purpose. It is provided "as is" without express or implied warranty.
43 : *
44 : *
45 : * Copyright (c) 1996-1998
46 : * Silicon Graphics Computer Systems, Inc.
47 : *
48 : * Permission to use, copy, modify, distribute and sell this software
49 : * and its documentation for any purpose is hereby granted without fee,
50 : * provided that the above copyright notice appear in all copies and
51 : * that both that copyright notice and this permission notice appear
52 : * in supporting documentation. Silicon Graphics makes no
53 : * representations about the suitability of this software for any
54 : * purpose. It is provided "as is" without express or implied warranty.
55 : */
56 :
57 : /** @file stl_iterator_base_types.h
58 : * This is an internal header file, included by other library headers.
59 : * You should not attempt to use it directly.
60 : *
61 : * This file contains all of the general iterator-related utility types,
62 : * such as iterator_traits and struct iterator.
63 : */
64 :
65 : #ifndef _STL_ITERATOR_BASE_TYPES_H
66 : #define _STL_ITERATOR_BASE_TYPES_H 1
67 :
68 : #pragma GCC system_header
69 :
70 : #include <bits/c++config.h>
71 : #include <cstddef>
72 :
73 : _GLIBCXX_BEGIN_NAMESPACE(std)
74 :
75 : //@{
76 : /**
77 : * @defgroup iterator_tags Iterator Tags
78 : * These are empty types, used to distinguish different iterators. The
79 : * distinction is not made by what they contain, but simply by what they
80 : * are. Different underlying algorithms can then be used based on the
81 : * different operations supported by different iterator types.
82 : */
83 : /// Marking input iterators.
84 : struct input_iterator_tag {};
85 : /// Marking output iterators.
86 : struct output_iterator_tag {};
87 : /// Forward iterators support a superset of input iterator operations.
88 : struct forward_iterator_tag : public input_iterator_tag {};
89 : /// Bidirectional iterators support a superset of forward iterator
90 : /// operations.
91 : struct bidirectional_iterator_tag : public forward_iterator_tag {};
92 : /// Random-access iterators support a superset of bidirectional iterator
93 : /// operations.
94 : struct random_access_iterator_tag : public bidirectional_iterator_tag {};
95 : //@}
96 :
97 :
98 : /**
99 : * @brief Common %iterator class.
100 : *
101 : * This class does nothing but define nested typedefs. %Iterator classes
102 : * can inherit from this class to save some work. The typedefs are then
103 : * used in specializations and overloading.
104 : *
105 : * In particular, there are no default implementations of requirements
106 : * such as @c operator++ and the like. (How could there be?)
107 : */
108 : template<typename _Category, typename _Tp, typename _Distance = ptrdiff_t,
109 : typename _Pointer = _Tp*, typename _Reference = _Tp&>
110 : struct iterator
111 304336 : {
112 : /// One of the @link iterator_tags tag types@endlink.
113 : typedef _Category iterator_category;
114 : /// The type "pointed to" by the iterator.
115 : typedef _Tp value_type;
116 : /// Distance between iterators is represented as this type.
117 : typedef _Distance difference_type;
118 : /// This type represents a pointer-to-value_type.
119 : typedef _Pointer pointer;
120 : /// This type represents a reference-to-value_type.
121 : typedef _Reference reference;
122 : };
123 :
124 : /**
125 : * This class does nothing but define nested typedefs. The general
126 : * version simply "forwards" the nested typedefs from the Iterator
127 : * argument. Specialized versions for pointers and pointers-to-const
128 : * provide tighter, more correct semantics.
129 : */
130 : template<typename _Iterator>
131 : struct iterator_traits
132 : {
133 : typedef typename _Iterator::iterator_category iterator_category;
134 : typedef typename _Iterator::value_type value_type;
135 : typedef typename _Iterator::difference_type difference_type;
136 : typedef typename _Iterator::pointer pointer;
137 : typedef typename _Iterator::reference reference;
138 : };
139 :
140 : template<typename _Tp>
141 : struct iterator_traits<_Tp*>
142 : {
143 : typedef random_access_iterator_tag iterator_category;
144 : typedef _Tp value_type;
145 : typedef ptrdiff_t difference_type;
146 : typedef _Tp* pointer;
147 : typedef _Tp& reference;
148 : };
149 :
150 : template<typename _Tp>
151 : struct iterator_traits<const _Tp*>
152 : {
153 : typedef random_access_iterator_tag iterator_category;
154 : typedef _Tp value_type;
155 : typedef ptrdiff_t difference_type;
156 : typedef const _Tp* pointer;
157 : typedef const _Tp& reference;
158 : };
159 :
160 : /**
161 : * This function is not a part of the C++ standard but is syntactic
162 : * sugar for internal library use only.
163 : */
164 : template<typename _Iter>
165 : inline typename iterator_traits<_Iter>::iterator_category
166 4730 : __iterator_category(const _Iter&)
167 4730 : { return typename iterator_traits<_Iter>::iterator_category(); }
168 :
169 : _GLIBCXX_END_NAMESPACE
170 :
171 : #endif /* _STL_ITERATOR_BASE_TYPES_H */
172 :
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