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
closing_iteratorboost::geometry::closing_iterator48     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
closing_iteratorboost::geometry::closing_iterator57     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
closing_iteratorboost::geometry::closing_iterator66     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 
dereferenceboost::geometry::closing_iterator75     inline typename boost::range_value<Range>::type const& dereference() const
76     {
77         return *m_iterator;
78     }
79 
distance_toboost::geometry::closing_iterator80     inline difference_type distance_to(closing_iterator<Range> const& other) const
81     {
82         return other.m_index - this->m_index;
83     }
84 
equalboost::geometry::closing_iterator85     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 
incrementboost::geometry::closing_iterator91     inline void increment()
92     {
93         if (++m_index < m_size)
94         {
95             ++m_iterator;
96         }
97         else
98         {
99             update_iterator();
100         }
101     }
102 
decrementboost::geometry::closing_iterator103     inline void decrement()
104     {
105         if (m_index-- < m_size)
106         {
107             --m_iterator;
108         }
109         else
110         {
111             update_iterator();
112         }
113     }
114 
advanceboost::geometry::closing_iterator115     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 
update_iteratorboost::geometry::closing_iterator129     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
149