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_CONCATENATE_ITERATOR_HPP
11 #define BOOST_GEOMETRY_ITERATORS_CONCATENATE_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 
19 
20 namespace boost { namespace geometry
21 {
22 
23 
24 
25 template
26 <
27     typename Iterator1,
28     typename Iterator2,
29     typename Value,
30     typename Reference = Value&
31 >
32 class concatenate_iterator
33     : public boost::iterator_facade
34         <
35             concatenate_iterator<Iterator1, Iterator2, Value, Reference>,
36             Value,
37             boost::bidirectional_traversal_tag,
38             Reference
39         >
40 {
41 private:
42     Iterator1 m_it1, m_end1;
43     Iterator2 m_begin2, m_it2;
44 
45 public:
46     typedef Iterator1 first_iterator_type;
47     typedef Iterator2 second_iterator_type;
48 
49     // default constructor
concatenate_iterator()50     concatenate_iterator() {}
51 
52     // for begin
concatenate_iterator(Iterator1 it1,Iterator1 end1,Iterator2 begin2,Iterator2 it2)53     concatenate_iterator(Iterator1 it1, Iterator1 end1,
54                          Iterator2 begin2, Iterator2 it2)
55         : m_it1(it1), m_end1(end1), m_begin2(begin2), m_it2(it2)
56     {}
57 
58     // for end
concatenate_iterator(Iterator1 end1,Iterator2 begin2,Iterator2 end2)59     concatenate_iterator(Iterator1 end1, Iterator2 begin2, Iterator2 end2)
60         : m_it1(end1), m_end1(end1), m_begin2(begin2), m_it2(end2)
61     {}
62 
63     template
64     <
65         typename OtherIt1,
66         typename OtherIt2,
67         typename OtherValue,
68         typename OtherReference
69     >
concatenate_iterator(concatenate_iterator<OtherIt1,OtherIt2,OtherValue,OtherReference> const & other)70     concatenate_iterator(concatenate_iterator
71                          <
72                              OtherIt1,
73                              OtherIt2,
74                              OtherValue,
75                              OtherReference
76                          > const& other)
77         : m_it1(other.m_it1)
78         , m_end1(other.m_end1)
79         , m_begin2(other.m_begin2)
80         , m_it2(other.m_it2)
81     {
82         static const bool are_conv
83             = boost::is_convertible<OtherIt1, Iterator1>::value
84            && boost::is_convertible<OtherIt2, Iterator2>::value;
85 
86         BOOST_MPL_ASSERT_MSG((are_conv),
87                              NOT_CONVERTIBLE,
88                              (types<OtherIt1, OtherIt2>));
89     }
90 
91 private:
92     friend class boost::iterator_core_access;
93 
94     template <typename It1, typename It2, typename V, typename R>
95     friend class concatenate_iterator;
96 
dereference() const97     inline Reference dereference() const
98     {
99         if ( m_it1 == m_end1 )
100         {
101             return *m_it2;
102         }
103         return *m_it1;
104     }
105 
106     template
107     <
108         typename OtherIt1,
109         typename OtherIt2,
110         typename OtherValue,
111         typename OtherReference
112     >
equal(concatenate_iterator<OtherIt1,OtherIt2,OtherValue,OtherReference> const & other) const113     inline bool equal(concatenate_iterator
114                       <
115                           OtherIt1,
116                           OtherIt2,
117                           OtherValue,
118                           OtherReference
119                       > const& other) const
120     {
121         return m_it1 == other.m_it1 && m_it2 == other.m_it2;
122     }
123 
increment()124     inline void increment()
125     {
126         if ( m_it1 == m_end1 )
127         {
128             ++m_it2;
129         }
130         else
131         {
132             ++m_it1;
133         }
134     }
135 
decrement()136     inline void decrement()
137     {
138         if ( m_it2 == m_begin2 )
139         {
140             --m_it1;
141         }
142         else
143         {
144             --m_it2;
145         }
146     }
147 };
148 
149 
150 
151 }} // namespace boost::geometry
152 
153 #endif // BOOST_GEOMETRY_ITERATORS_CONCATENATE_ITERATOR_HPP
154