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/iterator_facade.hpp>
16 #include <boost/iterator/iterator_categories.hpp>
17 #include <boost/range.hpp>
18 
19 #include <boost/geometry/core/closure.hpp>
20 #include <boost/geometry/iterators/closing_iterator.hpp>
21 
22 
23 namespace boost { namespace geometry
24 {
25 
26 #ifndef DOXYGEN_NO_DETAIL
27 namespace detail { namespace segment_iterator
28 {
29 
30 
31 template <typename Range, closure_selector Closure = closure<Range>::value>
32 struct range_iterator_type
33 {
34     typedef typename boost::range_iterator<Range>::type type;
35 };
36 
37 template <typename Range>
38 struct range_iterator_type<Range, open>
39 {
40     typedef closing_iterator<Range> type;
41 };
42 
43 
44 
45 template <typename Range, closure_selector Closure = closure<Range>::value>
46 struct range_iterator_begin
47 {
48     static inline typename range_iterator_type<Range, Closure>::type
applyboost::geometry::detail::segment_iterator::range_iterator_begin49     apply(Range& range)
50     {
51         return boost::begin(range);
52     }
53 };
54 
55 template <typename Range>
56 struct range_iterator_begin<Range, open>
57 {
58     static inline typename range_iterator_type<Range, open>::type
applyboost::geometry::detail::segment_iterator::range_iterator_begin59     apply(Range& range)
60     {
61         return closing_iterator<Range>(range);
62     }
63 };
64 
65 
66 
67 template <typename Range, closure_selector Closure = closure<Range>::value>
68 struct range_iterator_end
69 {
70     static inline typename range_iterator_type<Range, Closure>::type
applyboost::geometry::detail::segment_iterator::range_iterator_end71     apply(Range& range)
72     {
73         return boost::end(range);
74     }
75 };
76 
77 template <typename Range>
78 struct range_iterator_end<Range, open>
79 {
80     static inline typename range_iterator_type<Range, open>::type
applyboost::geometry::detail::segment_iterator::range_iterator_end81     apply(Range& range)
82     {
83         return closing_iterator<Range>(range, true);
84     }
85 };
86 
87 
88 
89 
90 
91 
92 template <typename Range, typename Value, typename Reference = Value>
93 class range_segment_iterator
94     : public boost::iterator_facade
95         <
96             range_segment_iterator<Range, Value, Reference>,
97             Value,
98             boost::bidirectional_traversal_tag,
99             Reference
100         >
101 {
has_less_than_two_elements(Range const & r)102     static inline bool has_less_than_two_elements(Range const& r)
103     {
104         return boost::size(r) < ((closure<Range>::value == open) ? 1u : 2u);
105     }
106 
107 public:
108     typedef typename range_iterator_type<Range>::type iterator_type;
109 
110     // default constructor
range_segment_iterator()111     range_segment_iterator()
112         : m_it(), m_has_less_than_two_elements(false)
113     {}
114 
115     // for begin
range_segment_iterator(Range & r)116     range_segment_iterator(Range& r)
117         : m_it(range_iterator_begin<Range>::apply(r))
118         , m_has_less_than_two_elements(has_less_than_two_elements(r))
119     {}
120 
121     // for end
range_segment_iterator(Range & r,bool)122     range_segment_iterator(Range& r, bool)
123         : m_it(range_iterator_end<Range>::apply(r))
124         , m_has_less_than_two_elements(has_less_than_two_elements(r))
125     {
126         if (! m_has_less_than_two_elements)
127         {
128             // the range consists of at least two items
129             --m_it;
130         }
131     }
132 
133     template
134     <
135         typename OtherRange,
136         typename OtherValue,
137         typename OtherReference
138     >
range_segment_iterator(range_segment_iterator<OtherRange,OtherValue,OtherReference> const & other)139     range_segment_iterator(range_segment_iterator
140                            <
141                                OtherRange,
142                                OtherValue,
143                                OtherReference
144                            > const& other)
145         : m_it(other.m_it)
146     {
147         typedef typename range_segment_iterator
148             <
149                 OtherRange, OtherValue, OtherReference
150             >::iterator_type other_iterator_type;
151 
152         static const bool are_conv
153             = boost::is_convertible<other_iterator_type, iterator_type>::value;
154 
155         BOOST_MPL_ASSERT_MSG((are_conv), NOT_CONVERTIBLE, (types<OtherRange>));
156     }
157 
158 private:
159     friend class boost::iterator_core_access;
160 
161     template <typename Rng, typename V, typename R>
162     friend class range_segment_iterator;
163 
dereference() const164     inline Reference dereference() const
165     {
166         if (m_has_less_than_two_elements)
167         {
168             return Reference(*m_it, *m_it);
169         }
170 
171         iterator_type next(m_it);
172         ++next;
173         return Reference(*m_it, *next);
174     }
175 
176     template
177     <
178         typename OtherRange,
179         typename OtherValue,
180         typename OtherReference
181     >
equal(range_segment_iterator<OtherRange,OtherValue,OtherReference> const & other) const182     inline bool equal(range_segment_iterator
183                       <
184                           OtherRange,
185                           OtherValue,
186                           OtherReference
187                       > const& other) const
188     {
189         return m_it == other.m_it;
190     }
191 
increment()192     inline void increment()
193     {
194         ++m_it;
195     }
196 
decrement()197     inline void decrement()
198     {
199         --m_it;
200     }
201 
202 private:
203     iterator_type m_it;
204     bool m_has_less_than_two_elements;
205 };
206 
207 
208 }} // namespace detail::segment_iterator
209 #endif // DOXYGEN_NO_DETAIL
210 
211 }} // namespace boost::geometry
212 
213 
214 #endif // BOOST_GEOMETRY_ITERATORS_DETAIL_SEGMENT_ITERATOR_RANGE_SEGMENT_ITERATOR_HPP
215