1 // Types used in iterator implementation -*- C++ -*-
3 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
4 // Free Software Foundation, Inc.
6 // This file is part of the GNU ISO C++ Library. This library is free
7 // software; you can redistribute it and/or modify it under the
8 // terms of the GNU General Public License as published by the
9 // Free Software Foundation; either version 3, or (at your option)
12 // This library is distributed in the hope that it will be useful,
13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 // GNU General Public License for more details.
17 // Under Section 7 of GPL version 3, you are granted additional
18 // permissions described in the GCC Runtime Library Exception, version
19 // 3.1, as published by the Free Software Foundation.
21 // You should have received a copy of the GNU General Public License and
22 // a copy of the GCC Runtime Library Exception along with this program;
23 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
24 // <http://www.gnu.org/licenses/>.
29 * Hewlett-Packard Company
31 * Permission to use, copy, modify, distribute and sell this software
32 * and its documentation for any purpose is hereby granted without fee,
33 * provided that the above copyright notice appear in all copies and
34 * that both that copyright notice and this permission notice appear
35 * in supporting documentation. Hewlett-Packard Company makes no
36 * representations about the suitability of this software for any
37 * purpose. It is provided "as is" without express or implied warranty.
40 * Copyright (c) 1996-1998
41 * Silicon Graphics Computer Systems, Inc.
43 * Permission to use, copy, modify, distribute and sell this software
44 * and its documentation for any purpose is hereby granted without fee,
45 * provided that the above copyright notice appear in all copies and
46 * that both that copyright notice and this permission notice appear
47 * in supporting documentation. Silicon Graphics makes no
48 * representations about the suitability of this software for any
49 * purpose. It is provided "as is" without express or implied warranty.
52 /** @file stl_iterator_base_types.h
53 * This is an internal header file, included by other library headers.
54 * You should not attempt to use it directly.
56 * This file contains all of the general iterator-related utility types,
57 * such as iterator_traits and struct iterator.
60 #ifndef _STL_ITERATOR_BASE_TYPES_H
61 #define _STL_ITERATOR_BASE_TYPES_H 1
63 #pragma GCC system_header
65 #include <bits/c++config.h>
67 _GLIBCXX_BEGIN_NAMESPACE(std
)
70 * @defgroup iterators Iterators
71 * Abstractions for uniform iterating through various underlying types.
76 * @defgroup iterator_tags Iterator Tags
77 * These are empty types, used to distinguish different iterators. The
78 * distinction is not made by what they contain, but simply by what they
79 * are. Different underlying algorithms can then be used based on the
80 * different operations supported by different iterator types.
83 /// Marking input iterators.
84 struct input_iterator_tag
{ };
86 /// Marking output iterators.
87 struct output_iterator_tag
{ };
89 /// Forward iterators support a superset of input iterator operations.
90 struct forward_iterator_tag
: public input_iterator_tag
{ };
92 /// Bidirectional iterators support a superset of forward iterator
94 struct bidirectional_iterator_tag
: public forward_iterator_tag
{ };
96 /// Random-access iterators support a superset of bidirectional
97 /// iterator operations.
98 struct random_access_iterator_tag
: public bidirectional_iterator_tag
{ };
102 * @brief Common %iterator class.
104 * This class does nothing but define nested typedefs. %Iterator classes
105 * can inherit from this class to save some work. The typedefs are then
106 * used in specializations and overloading.
108 * In particular, there are no default implementations of requirements
109 * such as @c operator++ and the like. (How could there be?)
111 template<typename _Category
, typename _Tp
, typename _Distance
= ptrdiff_t,
112 typename _Pointer
= _Tp
*, typename _Reference
= _Tp
&>
115 /// One of the @link iterator_tags tag types@endlink.
116 typedef _Category iterator_category
;
117 /// The type "pointed to" by the iterator.
118 typedef _Tp value_type
;
119 /// Distance between iterators is represented as this type.
120 typedef _Distance difference_type
;
121 /// This type represents a pointer-to-value_type.
122 typedef _Pointer pointer
;
123 /// This type represents a reference-to-value_type.
124 typedef _Reference reference
;
128 * @brief Traits class for iterators.
130 * This class does nothing but define nested typedefs. The general
131 * version simply @a forwards the nested typedefs from the Iterator
132 * argument. Specialized versions for pointers and pointers-to-const
133 * provide tighter, more correct semantics.
135 template<typename _Iterator
>
136 struct iterator_traits
138 typedef typename
_Iterator::iterator_category iterator_category
;
139 typedef typename
_Iterator::value_type value_type
;
140 typedef typename
_Iterator::difference_type difference_type
;
141 typedef typename
_Iterator::pointer pointer
;
142 typedef typename
_Iterator::reference reference
;
145 /// Partial specialization for pointer types.
146 template<typename _Tp
>
147 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
;
156 /// Partial specialization for const pointer types.
157 template<typename _Tp
>
158 struct iterator_traits
<const _Tp
*>
160 typedef random_access_iterator_tag iterator_category
;
161 typedef _Tp value_type
;
162 typedef ptrdiff_t difference_type
;
163 typedef const _Tp
* pointer
;
164 typedef const _Tp
& reference
;
168 * This function is not a part of the C++ standard but is syntactic
169 * sugar for internal library use only.
171 template<typename _Iter
>
172 inline typename iterator_traits
<_Iter
>::iterator_category
173 __iterator_category(const _Iter
&)
174 { return typename iterator_traits
<_Iter
>::iterator_category(); }
178 // If _Iterator has a base returns it otherwise _Iterator is returned
180 template<typename _Iterator
, bool _HasBase
>
183 typedef _Iterator iterator_type
;
184 static iterator_type
_S_base(_Iterator __it
)
188 template<typename _Iterator
>
189 struct _Iter_base
<_Iterator
, true>
191 typedef typename
_Iterator::iterator_type iterator_type
;
192 static iterator_type
_S_base(_Iterator __it
)
193 { return __it
.base(); }
196 _GLIBCXX_END_NAMESPACE
198 #endif /* _STL_ITERATOR_BASE_TYPES_H */