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1 : // Types used in iterator implementation -*- C++ -*-
2 :
3 : // Copyright (C) 2001-2013 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 3, 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 : // Under Section 7 of GPL version 3, you are granted additional
17 : // permissions described in the GCC Runtime Library Exception, version
18 : // 3.1, as published by the Free Software Foundation.
19 :
20 : // You should have received a copy of the GNU General Public License and
21 : // a copy of the GCC Runtime Library Exception along with this program;
22 : // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 : // <http://www.gnu.org/licenses/>.
24 :
25 : /*
26 : *
27 : * Copyright (c) 1994
28 : * Hewlett-Packard Company
29 : *
30 : * Permission to use, copy, modify, distribute and sell this software
31 : * and its documentation for any purpose is hereby granted without fee,
32 : * provided that the above copyright notice appear in all copies and
33 : * that both that copyright notice and this permission notice appear
34 : * in supporting documentation. Hewlett-Packard Company makes no
35 : * representations about the suitability of this software for any
36 : * purpose. It is provided "as is" without express or implied warranty.
37 : *
38 : *
39 : * Copyright (c) 1996-1998
40 : * Silicon Graphics Computer Systems, Inc.
41 : *
42 : * Permission to use, copy, modify, distribute and sell this software
43 : * and its documentation for any purpose is hereby granted without fee,
44 : * provided that the above copyright notice appear in all copies and
45 : * that both that copyright notice and this permission notice appear
46 : * in supporting documentation. Silicon Graphics makes no
47 : * representations about the suitability of this software for any
48 : * purpose. It is provided "as is" without express or implied warranty.
49 : */
50 :
51 : /** @file bits/stl_iterator_base_types.h
52 : * This is an internal header file, included by other library headers.
53 : * Do not attempt to use it directly. @headername{iterator}
54 : *
55 : * This file contains all of the general iterator-related utility types,
56 : * such as iterator_traits and struct iterator.
57 : */
58 :
59 : #ifndef _STL_ITERATOR_BASE_TYPES_H
60 : #define _STL_ITERATOR_BASE_TYPES_H 1
61 :
62 : #pragma GCC system_header
63 :
64 : #include <bits/c++config.h>
65 :
66 : #if __cplusplus >= 201103L
67 : # include <type_traits> // For _GLIBCXX_HAS_NESTED_TYPE, is_convertible
68 : #endif
69 :
70 : namespace std _GLIBCXX_VISIBILITY(default)
71 : {
72 : _GLIBCXX_BEGIN_NAMESPACE_VERSION
73 :
74 : /**
75 : * @defgroup iterators Iterators
76 : * Abstractions for uniform iterating through various underlying types.
77 : */
78 : //@{
79 :
80 : /**
81 : * @defgroup iterator_tags Iterator Tags
82 : * These are empty types, used to distinguish different iterators. The
83 : * distinction is not made by what they contain, but simply by what they
84 : * are. Different underlying algorithms can then be used based on the
85 : * different operations supported by different iterator types.
86 : */
87 : //@{
88 : /// Marking input iterators.
89 : struct input_iterator_tag { };
90 :
91 : /// Marking output iterators.
92 : struct output_iterator_tag { };
93 :
94 : /// Forward iterators support a superset of input iterator operations.
95 : struct forward_iterator_tag : public input_iterator_tag { };
96 :
97 : /// Bidirectional iterators support a superset of forward iterator
98 : /// operations.
99 : struct bidirectional_iterator_tag : public forward_iterator_tag { };
100 :
101 : /// Random-access iterators support a superset of bidirectional
102 : /// iterator operations.
103 : struct random_access_iterator_tag : public bidirectional_iterator_tag { };
104 : //@}
105 :
106 : /**
107 : * @brief Common %iterator class.
108 : *
109 : * This class does nothing but define nested typedefs. %Iterator classes
110 : * can inherit from this class to save some work. The typedefs are then
111 : * used in specializations and overloading.
112 : *
113 : * In particular, there are no default implementations of requirements
114 : * such as @c operator++ and the like. (How could there be?)
115 : */
116 : template<typename _Category, typename _Tp, typename _Distance = ptrdiff_t,
117 : typename _Pointer = _Tp*, typename _Reference = _Tp&>
118 168 : struct iterator
119 : {
120 : /// One of the @link iterator_tags tag types@endlink.
121 : typedef _Category iterator_category;
122 : /// The type "pointed to" by the iterator.
123 : typedef _Tp value_type;
124 : /// Distance between iterators is represented as this type.
125 : typedef _Distance difference_type;
126 : /// This type represents a pointer-to-value_type.
127 : typedef _Pointer pointer;
128 : /// This type represents a reference-to-value_type.
129 : typedef _Reference reference;
130 : };
131 :
132 : /**
133 : * @brief Traits class for iterators.
134 : *
135 : * This class does nothing but define nested typedefs. The general
136 : * version simply @a forwards the nested typedefs from the Iterator
137 : * argument. Specialized versions for pointers and pointers-to-const
138 : * provide tighter, more correct semantics.
139 : */
140 : #if __cplusplus >= 201103L
141 :
142 : _GLIBCXX_HAS_NESTED_TYPE(iterator_category)
143 :
144 : template<typename _Iterator,
145 : bool = __has_iterator_category<_Iterator>::value>
146 : struct __iterator_traits { };
147 :
148 : template<typename _Iterator>
149 : struct __iterator_traits<_Iterator, true>
150 : {
151 : typedef typename _Iterator::iterator_category iterator_category;
152 : typedef typename _Iterator::value_type value_type;
153 : typedef typename _Iterator::difference_type difference_type;
154 : typedef typename _Iterator::pointer pointer;
155 : typedef typename _Iterator::reference reference;
156 : };
157 :
158 : template<typename _Iterator>
159 : struct iterator_traits
160 : : public __iterator_traits<_Iterator> { };
161 : #else
162 : template<typename _Iterator>
163 : struct iterator_traits
164 : {
165 : typedef typename _Iterator::iterator_category iterator_category;
166 : typedef typename _Iterator::value_type value_type;
167 : typedef typename _Iterator::difference_type difference_type;
168 : typedef typename _Iterator::pointer pointer;
169 : typedef typename _Iterator::reference reference;
170 : };
171 : #endif
172 :
173 : /// Partial specialization for pointer types.
174 : template<typename _Tp>
175 : struct iterator_traits<_Tp*>
176 : {
177 : typedef random_access_iterator_tag iterator_category;
178 : typedef _Tp value_type;
179 : typedef ptrdiff_t difference_type;
180 : typedef _Tp* pointer;
181 : typedef _Tp& reference;
182 : };
183 :
184 : /// Partial specialization for const pointer types.
185 : template<typename _Tp>
186 : struct iterator_traits<const _Tp*>
187 : {
188 : typedef random_access_iterator_tag iterator_category;
189 : typedef _Tp value_type;
190 : typedef ptrdiff_t difference_type;
191 : typedef const _Tp* pointer;
192 : typedef const _Tp& reference;
193 : };
194 :
195 : /**
196 : * This function is not a part of the C++ standard but is syntactic
197 : * sugar for internal library use only.
198 : */
199 : template<typename _Iter>
200 : inline typename iterator_traits<_Iter>::iterator_category
201 1291561 : __iterator_category(const _Iter&)
202 1291561 : { return typename iterator_traits<_Iter>::iterator_category(); }
203 :
204 : //@}
205 :
206 : // If _Iterator has a base returns it otherwise _Iterator is returned
207 : // untouched
208 : template<typename _Iterator, bool _HasBase>
209 : struct _Iter_base
210 : {
211 : typedef _Iterator iterator_type;
212 14248 : static iterator_type _S_base(_Iterator __it)
213 14248 : { return __it; }
214 : };
215 :
216 : template<typename _Iterator>
217 : struct _Iter_base<_Iterator, true>
218 : {
219 : typedef typename _Iterator::iterator_type iterator_type;
220 1118 : static iterator_type _S_base(_Iterator __it)
221 1118 : { return __it.base(); }
222 : };
223 :
224 : #if __cplusplus >= 201103L
225 : template<typename _InIter>
226 : using _RequireInputIter = typename
227 : enable_if<is_convertible<typename
228 : iterator_traits<_InIter>::iterator_category,
229 : input_iterator_tag>::value>::type;
230 : #endif
231 :
232 : _GLIBCXX_END_NAMESPACE_VERSION
233 : } // namespace
234 :
235 : #endif /* _STL_ITERATOR_BASE_TYPES_H */
236 :
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