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1 | // Boost.Geometry (aka GGL, Generic Geometry Library) |
2 | ||
3 | // Copyright (c) 2007-2012 Barend Gehrels, Amsterdam, the Netherlands. | |
4 | // Copyright (c) 2008-2012 Bruno Lalande, Paris, France. | |
5 | // Copyright (c) 2009-2012 Mateusz Loskot, London, UK. | |
6 | ||
7 | // Parts of Boost.Geometry are redesigned from Geodan's Geographic Library | |
8 | // (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands. | |
9 | ||
10 | // Use, modification and distribution is subject to the Boost Software License, | |
11 | // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at | |
12 | // http://www.boost.org/LICENSE_1_0.txt) | |
13 | ||
14 | #ifndef BOOST_GEOMETRY_ITERATORS_CLOSING_ITERATOR_HPP | |
15 | #define BOOST_GEOMETRY_ITERATORS_CLOSING_ITERATOR_HPP | |
16 | ||
17 | #include <boost/range.hpp> | |
18 | #include <boost/iterator.hpp> | |
19 | #include <boost/iterator/iterator_facade.hpp> | |
20 | #include <boost/iterator/iterator_categories.hpp> | |
21 | ||
22 | ||
23 | ||
24 | namespace boost { namespace geometry | |
25 | { | |
26 | ||
27 | /*! | |
28 | \brief Iterator which iterates through a range, but adds first element at end of the range | |
29 | \tparam Range range on which this class is based on | |
30 | \ingroup iterators | |
31 | \note It's const iterator treating the Range as one containing non-mutable elements. | |
32 | For both "closing_iterator<Range> and "closing_iterator<Range const> | |
33 | const reference is always returned when dereferenced. | |
34 | \note This class is normally used from "closeable_view" if Close==true | |
35 | */ | |
36 | template <typename Range> | |
37 | struct closing_iterator | |
38 | : public boost::iterator_facade | |
39 | < | |
40 | closing_iterator<Range>, | |
41 | typename boost::range_value<Range>::type const, | |
42 | boost::random_access_traversal_tag | |
43 | > | |
44 | { | |
45 | typedef typename boost::range_difference<Range>::type difference_type; | |
46 | ||
47 | /// Constructor including the range it is based on | |
48 | explicit inline closing_iterator(Range& range) | |
49 | : m_range(&range) | |
50 | , m_iterator(boost::begin(range)) | |
51 | , m_end(boost::end(range)) | |
52 | , m_size(static_cast<difference_type>(boost::size(range))) | |
53 | , m_index(0) | |
54 | {} | |
55 | ||
56 | /// Constructor to indicate the end of a range | |
57 | explicit inline closing_iterator(Range& range, bool) | |
58 | : m_range(&range) | |
59 | , m_iterator(boost::end(range)) | |
60 | , m_end(boost::end(range)) | |
61 | , m_size(static_cast<difference_type>(boost::size(range))) | |
62 | , m_index((m_size == 0) ? 0 : m_size + 1) | |
63 | {} | |
64 | ||
65 | /// Default constructor | |
66 | explicit inline closing_iterator() | |
67 | : m_range(NULL) | |
68 | , m_size(0) | |
69 | , m_index(0) | |
70 | {} | |
71 | ||
72 | private: | |
73 | friend class boost::iterator_core_access; | |
74 | ||
75 | inline typename boost::range_value<Range>::type const& dereference() const | |
76 | { | |
77 | return *m_iterator; | |
78 | } | |
79 | ||
80 | inline difference_type distance_to(closing_iterator<Range> const& other) const | |
81 | { | |
82 | return other.m_index - this->m_index; | |
83 | } | |
84 | ||
85 | inline bool equal(closing_iterator<Range> const& other) const | |
86 | { | |
87 | return this->m_range == other.m_range | |
88 | && this->m_index == other.m_index; | |
89 | } | |
90 | ||
91 | inline void increment() | |
92 | { | |
93 | if (++m_index < m_size) | |
94 | { | |
95 | ++m_iterator; | |
96 | } | |
97 | else | |
98 | { | |
99 | update_iterator(); | |
100 | } | |
101 | } | |
102 | ||
103 | inline void decrement() | |
104 | { | |
105 | if (m_index-- < m_size) | |
106 | { | |
107 | --m_iterator; | |
108 | } | |
109 | else | |
110 | { | |
111 | update_iterator(); | |
112 | } | |
113 | } | |
114 | ||
115 | inline void advance(difference_type n) | |
116 | { | |
117 | if (m_index < m_size && m_index + n < m_size) | |
118 | { | |
119 | m_index += n; | |
120 | m_iterator += n; | |
121 | } | |
122 | else | |
123 | { | |
124 | m_index += n; | |
125 | update_iterator(); | |
126 | } | |
127 | } | |
128 | ||
129 | inline void update_iterator() | |
130 | { | |
131 | this->m_iterator = m_index <= m_size | |
132 | ? boost::begin(*m_range) + (m_index % m_size) | |
133 | : boost::end(*m_range) | |
134 | ; | |
135 | } | |
136 | ||
137 | Range* m_range; | |
138 | typename boost::range_iterator<Range>::type m_iterator; | |
139 | typename boost::range_iterator<Range>::type m_end; | |
140 | difference_type m_size; | |
141 | difference_type m_index; | |
142 | }; | |
143 | ||
144 | ||
145 | }} // namespace boost::geometry | |
146 | ||
147 | ||
148 | #endif // BOOST_GEOMETRY_ITERATORS_CLOSING_ITERATOR_HPP |