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1 | /*============================================================================== |
2 | Copyright (c) 2013 Jamboree | |
3 | ||
4 | Distributed under the Boost Software License, Version 1.0. (See accompanying | |
5 | file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) | |
6 | ==============================================================================*/ | |
7 | #ifndef BOOST_FUSION_FLATTEN_VIEW_ITERATOR_HPP_INCLUDED | |
8 | #define BOOST_FUSION_FLATTEN_VIEW_ITERATOR_HPP_INCLUDED | |
9 | ||
10 | ||
11 | #include <boost/fusion/support/config.hpp> | |
12 | #include <boost/mpl/bool.hpp> | |
13 | #include <boost/mpl/eval_if.hpp> | |
14 | #include <boost/type_traits/remove_reference.hpp> | |
15 | #include <boost/fusion/container/list/cons.hpp> | |
16 | #include <boost/fusion/support/unused.hpp> | |
17 | #include <boost/fusion/include/equal_to.hpp> | |
18 | #include <boost/fusion/iterator/next.hpp> | |
19 | #include <boost/fusion/iterator/deref.hpp> | |
20 | #include <boost/fusion/iterator/value_of.hpp> | |
21 | ||
22 | ||
23 | namespace boost { namespace fusion | |
24 | { | |
25 | struct forward_traversal_tag; | |
26 | struct flatten_view_iterator_tag; | |
27 | ||
28 | template<class First, class Base> | |
29 | struct flatten_view_iterator | |
30 | : iterator_base<flatten_view_iterator<First, Base> > | |
31 | { | |
32 | typedef flatten_view_iterator_tag fusion_tag; | |
33 | typedef forward_traversal_tag category; | |
34 | ||
35 | typedef convert_iterator<First> first_converter; | |
36 | typedef typename first_converter::type first_type; | |
37 | typedef Base base_type; | |
38 | ||
39 | BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED | |
40 | flatten_view_iterator(First const& first, Base const& base) | |
41 | : first(first), base(base) | |
42 | {} | |
43 | ||
44 | first_type first; | |
45 | base_type base; | |
46 | }; | |
47 | }} | |
48 | ||
49 | namespace boost { namespace fusion { namespace detail | |
50 | { | |
51 | template<class Iterator, class = void> | |
52 | struct make_descent_cons | |
53 | { | |
54 | typedef cons<Iterator> type; | |
55 | ||
56 | BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED | |
57 | static inline type apply(Iterator const& it) | |
58 | { | |
59 | return type(it); | |
60 | } | |
61 | }; | |
62 | ||
63 | template<class Iterator> | |
64 | struct make_descent_cons<Iterator, | |
65 | typename enable_if<traits::is_sequence< | |
66 | typename result_of::value_of<Iterator>::type> >::type> | |
67 | { | |
68 | // we use 'value_of' above for convenience, assuming the value won't be reference, | |
69 | // while we must use the regular 'deref' here for const issues... | |
70 | typedef typename | |
71 | remove_reference<typename result_of::deref<Iterator>::type>::type | |
72 | sub_sequence; | |
73 | ||
74 | typedef typename | |
75 | result_of::begin<sub_sequence>::type | |
76 | sub_begin; | |
77 | ||
78 | typedef cons<Iterator, typename make_descent_cons<sub_begin>::type> type; | |
79 | ||
80 | BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED | |
81 | static inline type apply(Iterator const& it) | |
82 | { | |
83 | return type(it, make_descent_cons<sub_begin>::apply( | |
84 | fusion::begin(*it))); | |
85 | } | |
86 | }; | |
87 | ||
88 | template<class Cons, class Base> | |
89 | struct build_flatten_view_iterator; | |
90 | ||
91 | template<class Car, class Base> | |
92 | struct build_flatten_view_iterator<cons<Car>, Base> | |
93 | { | |
94 | typedef flatten_view_iterator<Car, Base> type; | |
95 | ||
96 | BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED | |
97 | static inline type apply(cons<Car> const& cons, Base const& base) | |
98 | { | |
99 | return type(cons.car, base); | |
100 | } | |
101 | }; | |
102 | ||
103 | template<class Car, class Cdr, class Base> | |
104 | struct build_flatten_view_iterator<cons<Car, Cdr>, Base> | |
105 | { | |
106 | typedef flatten_view_iterator<Car, Base> next_base; | |
107 | typedef build_flatten_view_iterator<Cdr, next_base> next; | |
108 | typedef typename next::type type; | |
109 | ||
110 | BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED | |
111 | static inline type apply(cons<Car, Cdr> const& cons, Base const& base) | |
112 | { | |
113 | return next::apply(cons.cdr, next_base(cons.car, base)); | |
114 | } | |
115 | }; | |
116 | ||
117 | template<class Base, class Iterator, class = void> | |
118 | struct seek_descent | |
119 | { | |
120 | typedef make_descent_cons<Iterator> make_descent_cons_; | |
121 | typedef typename make_descent_cons_::type cons_type; | |
122 | typedef | |
123 | build_flatten_view_iterator<cons_type, Base> | |
124 | build_flatten_view_iterator_; | |
125 | typedef typename build_flatten_view_iterator_::type type; | |
126 | ||
127 | BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED | |
128 | static inline type apply(Base const& base, Iterator const& it) | |
129 | { | |
130 | return build_flatten_view_iterator_::apply( | |
131 | make_descent_cons_::apply(it), base); | |
132 | } | |
133 | }; | |
134 | ||
135 | template<class Base, class Iterator> | |
136 | struct seek_descent<Base, Iterator, | |
137 | typename enable_if< | |
138 | result_of::equal_to<Iterator, typename result_of::end< | |
139 | typename result_of::value_of<Base>::type>::type> >::type> | |
140 | { | |
141 | typedef typename result_of::next<Base>::type type; | |
142 | ||
143 | BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED | |
144 | static inline type apply(Base const& base, Iterator const&) | |
145 | { | |
146 | return fusion::next(base); | |
147 | } | |
148 | }; | |
149 | }}} | |
150 | ||
151 | namespace boost { namespace fusion { namespace extension | |
152 | { | |
153 | template<> | |
154 | struct next_impl<flatten_view_iterator_tag> | |
155 | { | |
156 | template<typename Iterator> | |
157 | struct apply | |
158 | { | |
159 | typedef typename Iterator::first_type first_type; | |
160 | typedef typename Iterator::base_type base_type; | |
161 | typedef typename result_of::next<first_type>::type next_type; | |
162 | ||
163 | typedef detail::seek_descent<base_type, next_type> seek_descent; | |
164 | typedef typename seek_descent::type type; | |
165 | ||
166 | BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED | |
167 | static inline | |
168 | type call(Iterator const& it) | |
169 | { | |
170 | return seek_descent::apply(it.base, fusion::next(it.first)); | |
171 | } | |
172 | }; | |
173 | }; | |
174 | ||
175 | template<> | |
176 | struct deref_impl<flatten_view_iterator_tag> | |
177 | { | |
178 | template<typename Iterator> | |
179 | struct apply | |
180 | { | |
181 | typedef typename | |
182 | result_of::deref<typename Iterator::first_type>::type | |
183 | type; | |
184 | ||
185 | BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED | |
186 | static inline | |
187 | type call(Iterator const& it) | |
188 | { | |
189 | return *it.first; | |
190 | } | |
191 | }; | |
192 | }; | |
193 | ||
194 | template<> | |
195 | struct value_of_impl<flatten_view_iterator_tag> | |
196 | { | |
197 | template<typename Iterator> | |
198 | struct apply | |
199 | { | |
200 | typedef typename | |
201 | result_of::value_of<typename Iterator::first_type>::type | |
202 | type; | |
203 | }; | |
204 | }; | |
205 | }}} | |
206 | ||
207 | #ifdef BOOST_FUSION_WORKAROUND_FOR_LWG_2408 | |
208 | namespace std | |
209 | { | |
210 | template <typename First, typename Base> | |
211 | struct iterator_traits< ::boost::fusion::flatten_view_iterator<First, Base> > | |
212 | { }; | |
213 | } | |
214 | #endif | |
215 | ||
216 | ||
217 | #endif | |
218 |