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1 | // Boost.TypeErasure library | |
2 | // | |
3 | // Copyright 2011 Steven Watanabe | |
4 | // | |
5 | // Distributed under the Boost Software License Version 1.0. (See | |
6 | // accompanying file LICENSE_1_0.txt or copy at | |
7 | // http://www.boost.org/LICENSE_1_0.txt) | |
8 | // | |
9 | // $Id$ | |
10 | ||
11 | #ifndef BOOST_TYPE_ERASURE_ITERATOR_HPP_INCLUDED | |
12 | #define BOOST_TYPE_ERASURE_ITERATOR_HPP_INCLUDED | |
13 | ||
14 | #include <iterator> | |
15 | #include <boost/mpl/vector.hpp> | |
16 | #include <boost/mpl/if.hpp> | |
17 | #include <boost/iterator/iterator_adaptor.hpp> | |
18 | #include <boost/iterator/iterator_categories.hpp> | |
19 | #include <boost/type_traits/remove_const.hpp> | |
20 | #include <boost/type_traits/remove_reference.hpp> | |
21 | #include <boost/type_erasure/operators.hpp> | |
22 | #include <boost/type_erasure/builtin.hpp> | |
23 | #include <boost/type_erasure/deduced.hpp> | |
24 | #include <boost/type_erasure/is_placeholder.hpp> | |
25 | ||
26 | namespace boost { | |
27 | ||
28 | namespace type_erasure { | |
29 | ||
30 | /** INTERNAL ONLY */ | |
31 | template<> | |
32 | struct is_placeholder< ::boost::use_default> : ::boost::mpl::false_ {}; | |
33 | ||
34 | namespace detail { | |
35 | ||
36 | template<class T> | |
37 | struct iterator_value_type_impl | |
38 | { | |
39 | typedef typename ::std::iterator_traits<T>::value_type type; | |
40 | }; | |
41 | ||
42 | } | |
43 | ||
44 | /** INTERNAL ONLY */ | |
45 | template<class T> | |
46 | struct iterator_value_type | |
47 | { | |
48 | typedef typename ::boost::mpl::eval_if< | |
49 | ::boost::type_erasure::is_placeholder<T>, | |
50 | ::boost::mpl::identity<void>, | |
51 | ::boost::type_erasure::detail::iterator_value_type_impl<T> | |
52 | >::type type; | |
53 | }; | |
54 | ||
55 | template< | |
56 | class Traversal, | |
57 | class T = _self, | |
58 | class Reference = ::boost::use_default, | |
59 | class DifferenceType = ::std::ptrdiff_t, | |
60 | class ValueType = typename deduced<iterator_value_type<T> >::type | |
61 | > | |
62 | struct iterator; | |
63 | ||
64 | #ifdef BOOST_TYPE_ERASURE_DOXYGEN | |
65 | ||
66 | /** | |
67 | * The @ref iterator concept can be used for any iterator category. | |
68 | * | |
69 | * \tparam Traversal must be one of @c boost::incrementable_traversal_tag, | |
70 | * @c boost::single_pass_traversal_tag, @c boost::forward_traversal_tag, | |
71 | * @c boost::bidirectional_traversal_tag, and @c boost::random_access_traversal_tag. | |
72 | * \tparam T The placeholder representing the iterator. | |
73 | * \tparam Reference The reference type. If it is boost::use_default, then | |
74 | * reference will be value_type&. | |
75 | * \tparam DifferenceType The iterator's difference type. | |
76 | * | |
77 | * The value_type of the iterator is deduced. To force it to be | |
78 | * a specific type, use the @ref same_type concept. | |
79 | * | |
80 | * Example: | |
81 | * | |
82 | * \code | |
83 | * mpl::vector< | |
84 | * iterator<boost::forward_traversal_tag>, | |
85 | * same_type<iterator<boost::forward_traversal_tag>::value_type, int> > int_it; | |
86 | * \endcode | |
87 | */ | |
88 | template< | |
89 | class Traversal, | |
90 | class T = _self, | |
91 | class Reference = boost::use_default, | |
92 | class DifferenceType = std::ptrdiff_t | |
93 | > | |
94 | struct iterator | |
95 | { | |
96 | typedef detail::unspecified value_type; | |
97 | typedef Reference reference; | |
98 | typedef DifferenceType difference_type; | |
99 | }; | |
100 | ||
101 | template< | |
102 | class T = _self, | |
103 | class Reference = boost::use_default, | |
104 | class DifferenceType = std::ptrdiff_t | |
105 | > | |
106 | struct forward_iterator : | |
107 | iterator<boost::forward_traversal_tag, T, Reference, DifferenceType> | |
108 | {}; | |
109 | ||
110 | template< | |
111 | class T = _self, | |
112 | class Reference = boost::use_default, | |
113 | class DifferenceType = std::ptrdiff_t | |
114 | > | |
115 | struct bidirectional_iterator : | |
116 | iterator<boost::bidirectional_traversal_tag, T, Reference, DifferenceType> | |
117 | {}; | |
118 | ||
119 | template< | |
120 | class T = _self, | |
121 | class Reference = boost::use_default, | |
122 | class DifferenceType = std::ptrdiff_t | |
123 | > | |
124 | struct random_access_iterator : | |
125 | iterator<boost::random_access_traversal_tag, T, Reference, DifferenceType> | |
126 | { | |
127 | }; | |
128 | ||
129 | #else | |
130 | ||
131 | /** INTERNAL ONLY */ | |
132 | template<class Reference, class ValueType> | |
133 | struct iterator_reference | |
134 | { | |
135 | typedef Reference type; | |
136 | }; | |
137 | ||
138 | /** INTERNAL ONLY */ | |
139 | template<class ValueType> | |
140 | struct iterator_reference< ::boost::use_default, ValueType> | |
141 | { | |
142 | typedef ValueType& type; | |
143 | }; | |
144 | ||
145 | template<class T, class Reference, class DifferenceType, class ValueType> | |
146 | struct iterator< ::boost::no_traversal_tag, T, Reference, DifferenceType, ValueType> : | |
147 | boost::mpl::vector< | |
148 | copy_constructible<T>, | |
149 | constructible<T()>, | |
150 | equality_comparable<T>, | |
151 | dereferenceable<typename iterator_reference<Reference, ValueType>::type, T>, | |
152 | assignable<T> | |
153 | > | |
154 | { | |
155 | typedef ValueType value_type; | |
156 | typedef typename iterator_reference<Reference, ValueType>::type reference; | |
157 | typedef DifferenceType difference_type; | |
158 | }; | |
159 | ||
160 | template<class T, class Reference, class DifferenceType, class ValueType> | |
161 | struct iterator< ::boost::incrementable_traversal_tag, T, Reference, DifferenceType, ValueType> : | |
162 | boost::mpl::vector< | |
163 | iterator< ::boost::no_traversal_tag, T, Reference, DifferenceType>, | |
164 | incrementable<T> | |
165 | > | |
166 | { | |
167 | typedef ValueType value_type; | |
168 | typedef typename iterator_reference<Reference, ValueType>::type reference; | |
169 | typedef DifferenceType difference_type; | |
170 | }; | |
171 | ||
172 | template<class T, class Reference, class DifferenceType, class ValueType> | |
173 | struct iterator< ::boost::single_pass_traversal_tag, T, Reference, DifferenceType, ValueType> : | |
174 | iterator< ::boost::incrementable_traversal_tag, T, Reference, DifferenceType, ValueType> | |
175 | {}; | |
176 | ||
177 | template<class T, class Reference, class DifferenceType, class ValueType> | |
178 | struct iterator< ::boost::forward_traversal_tag, T, Reference, DifferenceType, ValueType> : | |
179 | iterator< ::boost::incrementable_traversal_tag, T, Reference, DifferenceType, ValueType> | |
180 | {}; | |
181 | ||
182 | template<class T, class Reference, class DifferenceType, class ValueType> | |
183 | struct iterator< ::boost::bidirectional_traversal_tag, T, Reference, DifferenceType, ValueType> : | |
184 | boost::mpl::vector< | |
185 | iterator< ::boost::incrementable_traversal_tag, T, Reference, DifferenceType, ValueType>, | |
186 | decrementable<T> | |
187 | > | |
188 | { | |
189 | typedef ValueType value_type; | |
190 | typedef typename iterator_reference<Reference, ValueType>::type reference; | |
191 | typedef DifferenceType difference_type; | |
192 | }; | |
193 | ||
194 | template<class T, class Reference, class DifferenceType, class ValueType> | |
195 | struct iterator< ::boost::random_access_traversal_tag, T, Reference, DifferenceType, ValueType> : | |
196 | boost::mpl::vector< | |
197 | iterator< ::boost::bidirectional_traversal_tag, T, Reference, DifferenceType, ValueType>, | |
198 | addable<T, DifferenceType, T>, | |
199 | addable<DifferenceType, T, T>, | |
200 | subtractable<T, DifferenceType, T>, | |
201 | subtractable<T, T, DifferenceType>, | |
202 | subscriptable<typename iterator_reference<Reference, ValueType>::type, T, DifferenceType> | |
203 | > | |
204 | { | |
205 | typedef ValueType value_type; | |
206 | typedef typename iterator_reference<Reference, ValueType>::type reference; | |
207 | typedef DifferenceType difference_type; | |
208 | }; | |
209 | ||
210 | template< | |
211 | class T = _self, | |
212 | class Reference = ::boost::use_default, | |
213 | class DifferenceType = ::std::ptrdiff_t, | |
214 | class ValueType = typename deduced<iterator_value_type<T> >::type | |
215 | > | |
216 | struct forward_iterator : | |
217 | iterator< ::boost::forward_traversal_tag, T, Reference, DifferenceType, ValueType> | |
218 | {}; | |
219 | ||
220 | template< | |
221 | class T = _self, | |
222 | class Reference = ::boost::use_default, | |
223 | class DifferenceType = ::std::ptrdiff_t, | |
224 | class ValueType = typename deduced<iterator_value_type<T> >::type | |
225 | > | |
226 | struct bidirectional_iterator : | |
227 | iterator< ::boost::bidirectional_traversal_tag, T, Reference, DifferenceType, ValueType> | |
228 | {}; | |
229 | ||
230 | template< | |
231 | class T = _self, | |
232 | class Reference = ::boost::use_default, | |
233 | class DifferenceType = ::std::ptrdiff_t, | |
234 | class ValueType = typename deduced<iterator_value_type<T> >::type | |
235 | > | |
236 | struct random_access_iterator : | |
237 | iterator< ::boost::random_access_traversal_tag, T, Reference, DifferenceType, ValueType> | |
238 | { | |
239 | }; | |
240 | ||
241 | #endif | |
242 | ||
243 | /// \cond show_operators | |
244 | ||
245 | template<class T, class Reference, class DifferenceType, class ValueType, class Base> | |
246 | struct concept_interface<iterator< ::boost::no_traversal_tag, T, Reference, DifferenceType, ValueType>, Base, T> | |
247 | : Base | |
248 | { | |
249 | typedef typename rebind_any<Base, ValueType>::type value_type; | |
250 | typedef typename rebind_any< | |
251 | Base, | |
252 | typename iterator_reference<Reference, ValueType>::type | |
253 | >::type reference; | |
254 | typedef DifferenceType difference_type; | |
255 | typedef typename ::boost::mpl::if_< ::boost::is_reference<reference>, | |
256 | typename ::boost::remove_reference<reference>::type*, | |
257 | value_type* | |
258 | >::type pointer; | |
259 | }; | |
260 | ||
261 | template<class T, class Reference, class DifferenceType, class ValueType, class Base> | |
262 | struct concept_interface<iterator< ::boost::forward_traversal_tag, T, Reference, DifferenceType, ValueType>, Base, T> | |
263 | : Base | |
264 | { | |
265 | typedef std::forward_iterator_tag iterator_category; | |
266 | }; | |
267 | ||
268 | template<class T, class Reference, class DifferenceType, class ValueType, class Base> | |
269 | struct concept_interface<forward_iterator<T, Reference, DifferenceType, ValueType>, Base, T> | |
270 | : Base | |
271 | { | |
272 | typedef std::forward_iterator_tag iterator_category; | |
273 | }; | |
274 | ||
275 | template<class T, class Reference, class DifferenceType, class ValueType, class Base> | |
276 | struct concept_interface<iterator< ::boost::bidirectional_traversal_tag, T, Reference, DifferenceType, ValueType>, Base, T> | |
277 | : Base | |
278 | { | |
279 | typedef std::bidirectional_iterator_tag iterator_category; | |
280 | }; | |
281 | ||
282 | template<class T, class Reference, class DifferenceType, class ValueType, class Base> | |
283 | struct concept_interface<bidirectional_iterator<T, Reference, DifferenceType, ValueType>, Base, T> | |
284 | : Base | |
285 | { | |
286 | typedef std::bidirectional_iterator_tag iterator_category; | |
287 | }; | |
288 | ||
289 | template<class T, class Reference, class DifferenceType, class ValueType, class Base> | |
290 | struct concept_interface<iterator< ::boost::random_access_traversal_tag, T, Reference, DifferenceType, ValueType>, Base, T> | |
291 | : Base | |
292 | { | |
293 | typedef std::random_access_iterator_tag iterator_category; | |
294 | }; | |
295 | ||
296 | template<class T, class Reference, class DifferenceType, class ValueType, class Base> | |
297 | struct concept_interface<random_access_iterator<T, Reference, DifferenceType, ValueType>, Base, T> | |
298 | : Base | |
299 | { | |
300 | typedef std::random_access_iterator_tag iterator_category; | |
301 | }; | |
302 | ||
303 | /// \endcond | |
304 | ||
305 | } | |
306 | } | |
307 | ||
308 | #endif |