1 // Boost.Geometry (aka GGL, Generic Geometry Library)
3 // Copyright (c) 2014, Oracle and/or its affiliates.
5 // Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle
7 // Licensed under the Boost Software License version 1.0.
8 // http://www.boost.org/users/license.html
10 #ifndef BOOST_GEOMETRY_ITERATORS_DETAIL_SEGMENT_ITERATOR_RANGE_SEGMENT_ITERATOR_HPP
11 #define BOOST_GEOMETRY_ITERATORS_DETAIL_SEGMENT_ITERATOR_RANGE_SEGMENT_ITERATOR_HPP
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>
20 #include <boost/geometry/core/closure.hpp>
21 #include <boost/geometry/iterators/closing_iterator.hpp>
24 namespace boost { namespace geometry
27 #ifndef DOXYGEN_NO_DETAIL
28 namespace detail { namespace segment_iterator
32 template <typename Range, closure_selector Closure = closure<Range>::value>
33 struct range_iterator_type
35 typedef typename boost::range_iterator<Range>::type type;
38 template <typename Range>
39 struct range_iterator_type<Range, open>
41 typedef closing_iterator<Range> type;
46 template <typename Range, closure_selector Closure = closure<Range>::value>
47 struct range_iterator_begin
49 static inline typename range_iterator_type<Range, Closure>::type
52 return boost::begin(range);
56 template <typename Range>
57 struct range_iterator_begin<Range, open>
59 static inline typename range_iterator_type<Range, open>::type
62 return closing_iterator<Range>(range);
68 template <typename Range, closure_selector Closure = closure<Range>::value>
69 struct range_iterator_end
71 static inline typename range_iterator_type<Range, Closure>::type
74 return boost::end(range);
78 template <typename Range>
79 struct range_iterator_end<Range, open>
81 static inline typename range_iterator_type<Range, open>::type
84 return closing_iterator<Range>(range, true);
93 template <typename Range, typename Value, typename Reference = Value>
94 class range_segment_iterator
95 : public boost::iterator_facade
97 range_segment_iterator<Range, Value, Reference>,
99 boost::bidirectional_traversal_tag,
103 static inline bool has_less_than_two_elements(Range const& r)
105 return boost::size(r) < ((closure<Range>::value == open) ? 1u : 2u);
109 typedef typename range_iterator_type<Range>::type iterator_type;
111 // default constructor
112 range_segment_iterator()
113 : m_it(), m_has_less_than_two_elements(false)
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))
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))
127 if (! m_has_less_than_two_elements)
129 // the range consists of at least two items
138 typename OtherReference
140 range_segment_iterator(range_segment_iterator
148 typedef typename range_segment_iterator
150 OtherRange, OtherValue, OtherReference
151 >::iterator_type other_iterator_type;
153 static const bool are_conv
154 = boost::is_convertible<other_iterator_type, iterator_type>::value;
156 BOOST_MPL_ASSERT_MSG((are_conv), NOT_CONVERTIBLE, (types<OtherRange>));
160 friend class boost::iterator_core_access;
162 template <typename Rng, typename V, typename R>
163 friend class range_segment_iterator;
165 inline Reference dereference() const
167 if (m_has_less_than_two_elements)
169 return Reference(*m_it, *m_it);
172 iterator_type next(m_it);
174 return Reference(*m_it, *next);
181 typename OtherReference
183 inline bool equal(range_segment_iterator
188 > const& other) const
190 return m_it == other.m_it;
193 inline void increment()
198 inline void decrement()
205 bool m_has_less_than_two_elements;
209 }} // namespace detail::segment_iterator
210 #endif // DOXYGEN_NO_DETAIL
212 }} // namespace boost::geometry
215 #endif // BOOST_GEOMETRY_ITERATORS_DETAIL_SEGMENT_ITERATOR_RANGE_SEGMENT_ITERATOR_HPP