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1 | // Boost.Geometry (aka GGL, Generic Geometry Library) |
2 | ||
3 | // Copyright (c) 2014, Oracle and/or its affiliates. | |
4 | ||
5 | // Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle | |
6 | ||
7 | // Licensed under the Boost Software License version 1.0. | |
8 | // http://www.boost.org/users/license.html | |
9 | ||
10 | #ifndef BOOST_GEOMETRY_ITERATORS_DETAIL_SEGMENT_ITERATOR_RANGE_SEGMENT_ITERATOR_HPP | |
11 | #define BOOST_GEOMETRY_ITERATORS_DETAIL_SEGMENT_ITERATOR_RANGE_SEGMENT_ITERATOR_HPP | |
12 | ||
13 | #include <boost/mpl/assert.hpp> | |
14 | #include <boost/type_traits/is_convertible.hpp> | |
15 | #include <boost/iterator.hpp> | |
16 | #include <boost/iterator/iterator_facade.hpp> | |
17 | #include <boost/iterator/iterator_categories.hpp> | |
18 | #include <boost/range.hpp> | |
19 | ||
20 | #include <boost/geometry/core/closure.hpp> | |
21 | #include <boost/geometry/iterators/closing_iterator.hpp> | |
22 | ||
23 | ||
24 | namespace boost { namespace geometry | |
25 | { | |
26 | ||
27 | #ifndef DOXYGEN_NO_DETAIL | |
28 | namespace detail { namespace segment_iterator | |
29 | { | |
30 | ||
31 | ||
32 | template <typename Range, closure_selector Closure = closure<Range>::value> | |
33 | struct range_iterator_type | |
34 | { | |
35 | typedef typename boost::range_iterator<Range>::type type; | |
36 | }; | |
37 | ||
38 | template <typename Range> | |
39 | struct range_iterator_type<Range, open> | |
40 | { | |
41 | typedef closing_iterator<Range> type; | |
42 | }; | |
43 | ||
44 | ||
45 | ||
46 | template <typename Range, closure_selector Closure = closure<Range>::value> | |
47 | struct range_iterator_begin | |
48 | { | |
49 | static inline typename range_iterator_type<Range, Closure>::type | |
50 | apply(Range& range) | |
51 | { | |
52 | return boost::begin(range); | |
53 | } | |
54 | }; | |
55 | ||
56 | template <typename Range> | |
57 | struct range_iterator_begin<Range, open> | |
58 | { | |
59 | static inline typename range_iterator_type<Range, open>::type | |
60 | apply(Range& range) | |
61 | { | |
62 | return closing_iterator<Range>(range); | |
63 | } | |
64 | }; | |
65 | ||
66 | ||
67 | ||
68 | template <typename Range, closure_selector Closure = closure<Range>::value> | |
69 | struct range_iterator_end | |
70 | { | |
71 | static inline typename range_iterator_type<Range, Closure>::type | |
72 | apply(Range& range) | |
73 | { | |
74 | return boost::end(range); | |
75 | } | |
76 | }; | |
77 | ||
78 | template <typename Range> | |
79 | struct range_iterator_end<Range, open> | |
80 | { | |
81 | static inline typename range_iterator_type<Range, open>::type | |
82 | apply(Range& range) | |
83 | { | |
84 | return closing_iterator<Range>(range, true); | |
85 | } | |
86 | }; | |
87 | ||
88 | ||
89 | ||
90 | ||
91 | ||
92 | ||
93 | template <typename Range, typename Value, typename Reference = Value> | |
94 | class range_segment_iterator | |
95 | : public boost::iterator_facade | |
96 | < | |
97 | range_segment_iterator<Range, Value, Reference>, | |
98 | Value, | |
99 | boost::bidirectional_traversal_tag, | |
100 | Reference | |
101 | > | |
102 | { | |
103 | static inline bool has_less_than_two_elements(Range const& r) | |
104 | { | |
105 | return boost::size(r) < ((closure<Range>::value == open) ? 1u : 2u); | |
106 | } | |
107 | ||
108 | public: | |
109 | typedef typename range_iterator_type<Range>::type iterator_type; | |
110 | ||
111 | // default constructor | |
112 | range_segment_iterator() | |
113 | : m_it(), m_has_less_than_two_elements(false) | |
114 | {} | |
115 | ||
116 | // for begin | |
117 | range_segment_iterator(Range& r) | |
118 | : m_it(range_iterator_begin<Range>::apply(r)) | |
119 | , m_has_less_than_two_elements(has_less_than_two_elements(r)) | |
120 | {} | |
121 | ||
122 | // for end | |
123 | range_segment_iterator(Range& r, bool) | |
124 | : m_it(range_iterator_end<Range>::apply(r)) | |
125 | , m_has_less_than_two_elements(has_less_than_two_elements(r)) | |
126 | { | |
127 | if (! m_has_less_than_two_elements) | |
128 | { | |
129 | // the range consists of at least two items | |
130 | --m_it; | |
131 | } | |
132 | } | |
133 | ||
134 | template | |
135 | < | |
136 | typename OtherRange, | |
137 | typename OtherValue, | |
138 | typename OtherReference | |
139 | > | |
140 | range_segment_iterator(range_segment_iterator | |
141 | < | |
142 | OtherRange, | |
143 | OtherValue, | |
144 | OtherReference | |
145 | > const& other) | |
146 | : m_it(other.m_it) | |
147 | { | |
148 | typedef typename range_segment_iterator | |
149 | < | |
150 | OtherRange, OtherValue, OtherReference | |
151 | >::iterator_type other_iterator_type; | |
152 | ||
153 | static const bool are_conv | |
154 | = boost::is_convertible<other_iterator_type, iterator_type>::value; | |
155 | ||
156 | BOOST_MPL_ASSERT_MSG((are_conv), NOT_CONVERTIBLE, (types<OtherRange>)); | |
157 | } | |
158 | ||
159 | private: | |
160 | friend class boost::iterator_core_access; | |
161 | ||
162 | template <typename Rng, typename V, typename R> | |
163 | friend class range_segment_iterator; | |
164 | ||
165 | inline Reference dereference() const | |
166 | { | |
167 | if (m_has_less_than_two_elements) | |
168 | { | |
169 | return Reference(*m_it, *m_it); | |
170 | } | |
171 | ||
172 | iterator_type next(m_it); | |
173 | ++next; | |
174 | return Reference(*m_it, *next); | |
175 | } | |
176 | ||
177 | template | |
178 | < | |
179 | typename OtherRange, | |
180 | typename OtherValue, | |
181 | typename OtherReference | |
182 | > | |
183 | inline bool equal(range_segment_iterator | |
184 | < | |
185 | OtherRange, | |
186 | OtherValue, | |
187 | OtherReference | |
188 | > const& other) const | |
189 | { | |
190 | return m_it == other.m_it; | |
191 | } | |
192 | ||
193 | inline void increment() | |
194 | { | |
195 | ++m_it; | |
196 | } | |
197 | ||
198 | inline void decrement() | |
199 | { | |
200 | --m_it; | |
201 | } | |
202 | ||
203 | private: | |
204 | iterator_type m_it; | |
205 | bool m_has_less_than_two_elements; | |
206 | }; | |
207 | ||
208 | ||
209 | }} // namespace detail::segment_iterator | |
210 | #endif // DOXYGEN_NO_DETAIL | |
211 | ||
212 | }} // namespace boost::geometry | |
213 | ||
214 | ||
215 | #endif // BOOST_GEOMETRY_ITERATORS_DETAIL_SEGMENT_ITERATOR_RANGE_SEGMENT_ITERATOR_HPP |