1 | // Types used in iterator implementation -*- C++ -*- |
2 | |
3 | // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 |
4 | // Free Software Foundation, Inc. |
5 | // |
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) |
10 | // any later version. |
11 | |
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. |
16 | |
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. |
20 | |
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/>. |
25 | |
26 | /* |
27 | * |
28 | * Copyright (c) 1994 |
29 | * Hewlett-Packard Company |
30 | * |
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. |
38 | * |
39 | * |
40 | * Copyright (c) 1996-1998 |
41 | * Silicon Graphics Computer Systems, Inc. |
42 | * |
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. |
50 | */ |
51 | |
52 | /** @file bits/stl_iterator_base_types.h |
53 | * This is an internal header file, included by other library headers. |
54 | * Do not attempt to use it directly. @headername{iterator} |
55 | * |
56 | * This file contains all of the general iterator-related utility types, |
57 | * such as iterator_traits and struct iterator. |
58 | */ |
59 | |
60 | #ifndef _STL_ITERATOR_BASE_TYPES_H |
61 | #define _STL_ITERATOR_BASE_TYPES_H 1 |
62 | |
63 | #pragma GCC system_header |
64 | |
65 | #include <bits/c++config.h> |
66 | |
67 | #ifdef __GXX_EXPERIMENTAL_CXX0X__ |
68 | # include <type_traits> // For _GLIBCXX_HAS_NESTED_TYPE |
69 | #endif |
70 | |
71 | namespace std _GLIBCXX_VISIBILITY(default) |
72 | { |
73 | _GLIBCXX_BEGIN_NAMESPACE_VERSION |
74 | |
75 | /** |
76 | * @defgroup iterators Iterators |
77 | * Abstractions for uniform iterating through various underlying types. |
78 | */ |
79 | //@{ |
80 | |
81 | /** |
82 | * @defgroup iterator_tags Iterator Tags |
83 | * These are empty types, used to distinguish different iterators. The |
84 | * distinction is not made by what they contain, but simply by what they |
85 | * are. Different underlying algorithms can then be used based on the |
86 | * different operations supported by different iterator types. |
87 | */ |
88 | //@{ |
89 | /// Marking input iterators. |
90 | struct input_iterator_tag { }; |
91 | |
92 | /// Marking output iterators. |
93 | struct output_iterator_tag { }; |
94 | |
95 | /// Forward iterators support a superset of input iterator operations. |
96 | struct forward_iterator_tag : public input_iterator_tag { }; |
97 | |
98 | /// Bidirectional iterators support a superset of forward iterator |
99 | /// operations. |
100 | struct bidirectional_iterator_tag : public forward_iterator_tag { }; |
101 | |
102 | /// Random-access iterators support a superset of bidirectional |
103 | /// iterator operations. |
104 | struct random_access_iterator_tag : public bidirectional_iterator_tag { }; |
105 | //@} |
106 | |
107 | /** |
108 | * @brief Common %iterator class. |
109 | * |
110 | * This class does nothing but define nested typedefs. %Iterator classes |
111 | * can inherit from this class to save some work. The typedefs are then |
112 | * used in specializations and overloading. |
113 | * |
114 | * In particular, there are no default implementations of requirements |
115 | * such as @c operator++ and the like. (How could there be?) |
116 | */ |
117 | template<typename _Category, typename _Tp, typename _Distance = ptrdiff_t, |
118 | typename _Pointer = _Tp*, typename _Reference = _Tp&> |
119 | struct iterator |
120 | { |
121 | /// One of the @link iterator_tags tag types@endlink. |
122 | typedef _Category iterator_category; |
123 | /// The type "pointed to" by the iterator. |
124 | typedef _Tp value_type; |
125 | /// Distance between iterators is represented as this type. |
126 | typedef _Distance difference_type; |
127 | /// This type represents a pointer-to-value_type. |
128 | typedef _Pointer pointer; |
129 | /// This type represents a reference-to-value_type. |
130 | typedef _Reference reference; |
131 | }; |
132 | |
133 | /** |
134 | * @brief Traits class for iterators. |
135 | * |
136 | * This class does nothing but define nested typedefs. The general |
137 | * version simply @a forwards the nested typedefs from the Iterator |
138 | * argument. Specialized versions for pointers and pointers-to-const |
139 | * provide tighter, more correct semantics. |
140 | */ |
141 | #ifdef __GXX_EXPERIMENTAL_CXX0X__ |
142 | |
143 | _GLIBCXX_HAS_NESTED_TYPE(iterator_category) |
144 | |
145 | template<typename _Iterator, |
146 | bool = __has_iterator_category<_Iterator>::value> |
147 | struct __iterator_traits { }; |
148 | |
149 | template<typename _Iterator> |
150 | struct __iterator_traits<_Iterator, true> |
151 | { |
152 | typedef typename _Iterator::iterator_category iterator_category; |
153 | typedef typename _Iterator::value_type value_type; |
154 | typedef typename _Iterator::difference_type difference_type; |
155 | typedef typename _Iterator::pointer pointer; |
156 | typedef typename _Iterator::reference reference; |
157 | }; |
158 | |
159 | template<typename _Iterator> |
160 | struct iterator_traits |
161 | : public __iterator_traits<_Iterator> { }; |
162 | #else |
163 | template<typename _Iterator> |
164 | struct iterator_traits |
165 | { |
166 | typedef typename _Iterator::iterator_category iterator_category; |
167 | typedef typename _Iterator::value_type value_type; |
168 | typedef typename _Iterator::difference_type difference_type; |
169 | typedef typename _Iterator::pointer pointer; |
170 | typedef typename _Iterator::reference reference; |
171 | }; |
172 | #endif |
173 | |
174 | /// Partial specialization for pointer types. |
175 | template<typename _Tp> |
176 | struct iterator_traits<_Tp*> |
177 | { |
178 | typedef random_access_iterator_tag iterator_category; |
179 | typedef _Tp value_type; |
180 | typedef ptrdiff_t difference_type; |
181 | typedef _Tp* pointer; |
182 | typedef _Tp& reference; |
183 | }; |
184 | |
185 | /// Partial specialization for const pointer types. |
186 | template<typename _Tp> |
187 | struct iterator_traits<const _Tp*> |
188 | { |
189 | typedef random_access_iterator_tag iterator_category; |
190 | typedef _Tp value_type; |
191 | typedef ptrdiff_t difference_type; |
192 | typedef const _Tp* pointer; |
193 | typedef const _Tp& reference; |
194 | }; |
195 | |
196 | /** |
197 | * This function is not a part of the C++ standard but is syntactic |
198 | * sugar for internal library use only. |
199 | */ |
200 | template<typename _Iter> |
201 | inline typename iterator_traits<_Iter>::iterator_category |
202 | __iterator_category(const _Iter&) |
203 | { return typename iterator_traits<_Iter>::iterator_category(); } |
204 | |
205 | //@} |
206 | |
207 | // If _Iterator has a base returns it otherwise _Iterator is returned |
208 | // untouched |
209 | template<typename _Iterator, bool _HasBase> |
210 | struct _Iter_base |
211 | { |
212 | typedef _Iterator iterator_type; |
213 | static iterator_type _S_base(_Iterator __it) |
214 | { return __it; } |
215 | }; |
216 | |
217 | template<typename _Iterator> |
218 | struct _Iter_base<_Iterator, true> |
219 | { |
220 | typedef typename _Iterator::iterator_type iterator_type; |
221 | static iterator_type _S_base(_Iterator __it) |
222 | { return __it.base(); } |
223 | }; |
224 | |
225 | _GLIBCXX_END_NAMESPACE_VERSION |
226 | } // namespace |
227 | |
228 | #endif /* _STL_ITERATOR_BASE_TYPES_H */ |
229 | |
230 | |