Line data Source code
1 : // Types used in iterator implementation -*- C++ -*-
2 :
3 : // Copyright (C) 2001-2016 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 __void_t, 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 18630 : 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 : // _GLIBCXX_RESOLVE_LIB_DEFECTS
142 : // 2408. SFINAE-friendly common_type/iterator_traits is missing in C++14
143 : template<typename _Iterator, typename = __void_t<>>
144 : struct __iterator_traits { };
145 :
146 : template<typename _Iterator>
147 : struct __iterator_traits<_Iterator,
148 : __void_t<typename _Iterator::iterator_category,
149 : typename _Iterator::value_type,
150 : typename _Iterator::difference_type,
151 : typename _Iterator::pointer,
152 : typename _Iterator::reference>>
153 : {
154 : typedef typename _Iterator::iterator_category iterator_category;
155 : typedef typename _Iterator::value_type value_type;
156 : typedef typename _Iterator::difference_type difference_type;
157 : typedef typename _Iterator::pointer pointer;
158 : typedef typename _Iterator::reference reference;
159 : };
160 :
161 : template<typename _Iterator>
162 : struct iterator_traits
163 : : public __iterator_traits<_Iterator> { };
164 : #else
165 : template<typename _Iterator>
166 : struct iterator_traits
167 : {
168 : typedef typename _Iterator::iterator_category iterator_category;
169 : typedef typename _Iterator::value_type value_type;
170 : typedef typename _Iterator::difference_type difference_type;
171 : typedef typename _Iterator::pointer pointer;
172 : typedef typename _Iterator::reference reference;
173 : };
174 : #endif
175 :
176 : /// Partial specialization for pointer types.
177 : template<typename _Tp>
178 : struct iterator_traits<_Tp*>
179 : {
180 : typedef random_access_iterator_tag iterator_category;
181 : typedef _Tp value_type;
182 : typedef ptrdiff_t difference_type;
183 : typedef _Tp* pointer;
184 : typedef _Tp& reference;
185 : };
186 :
187 : /// Partial specialization for const pointer types.
188 : template<typename _Tp>
189 : struct iterator_traits<const _Tp*>
190 : {
191 : typedef random_access_iterator_tag iterator_category;
192 : typedef _Tp value_type;
193 : typedef ptrdiff_t difference_type;
194 : typedef const _Tp* pointer;
195 : typedef const _Tp& reference;
196 : };
197 :
198 : /**
199 : * This function is not a part of the C++ standard but is syntactic
200 : * sugar for internal library use only.
201 : */
202 : template<typename _Iter>
203 : inline typename iterator_traits<_Iter>::iterator_category
204 350 : __iterator_category(const _Iter&)
205 350 : { return typename iterator_traits<_Iter>::iterator_category(); }
206 :
207 : //@}
208 :
209 : #if __cplusplus < 201103L
210 : // If _Iterator has a base returns it otherwise _Iterator is returned
211 : // untouched
212 : template<typename _Iterator, bool _HasBase>
213 : struct _Iter_base
214 : {
215 : typedef _Iterator iterator_type;
216 : static iterator_type _S_base(_Iterator __it)
217 : { return __it; }
218 : };
219 :
220 : template<typename _Iterator>
221 : struct _Iter_base<_Iterator, true>
222 : {
223 : typedef typename _Iterator::iterator_type iterator_type;
224 : static iterator_type _S_base(_Iterator __it)
225 : { return __it.base(); }
226 : };
227 : #endif
228 :
229 : #if __cplusplus >= 201103L
230 : template<typename _InIter>
231 : using _RequireInputIter = typename
232 : enable_if<is_convertible<typename
233 : iterator_traits<_InIter>::iterator_category,
234 : input_iterator_tag>::value>::type;
235 : #endif
236 :
237 : _GLIBCXX_END_NAMESPACE_VERSION
238 : } // namespace
239 :
240 : #endif /* _STL_ITERATOR_BASE_TYPES_H */
241 :
|
