ceph/src/boost/boost/geometry/iterators/detail/segment_iterator/range_segment_iterator.hpp

   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.hpp>
  16 #include <boost/iterator/iterator_facade.hpp>
  17 #include <boost/iterator/iterator_categories.hpp>
  18 #include <boost/range.hpp>
  19
  20 #include <boost/geometry/core/closure.hpp>
  21 #include <boost/geometry/iterators/closing_iterator.hpp>
  22
  23
  24 namespace boost { namespace geometry
  25 {
  26
  27 #ifndef DOXYGEN_NO_DETAIL
  28 namespace detail { namespace segment_iterator
  29 {
  30
  31
  32 template <typename Range, closure_selector Closure = closure<Range>::value>
  33 struct range_iterator_type
  34 {
  35     typedef typename boost::range_iterator<Range>::type type;
  36 };
  37
  38 template <typename Range>
  39 struct range_iterator_type<Range, open>
  40 {
  41     typedef closing_iterator<Range> type;
  42 };
  43
  44
  45
  46 template <typename Range, closure_selector Closure = closure<Range>::value>
  47 struct range_iterator_begin
  48 {
  49     static inline typename range_iterator_type<Range, Closure>::type
  50     apply(Range& range)
  51     {
  52         return boost::begin(range);
  53     }
  54 };
  55
  56 template <typename Range>
  57 struct range_iterator_begin<Range, open>
  58 {
  59     static inline typename range_iterator_type<Range, open>::type
  60     apply(Range& range)
  61     {
  62         return closing_iterator<Range>(range);
  63     }
  64 };
  65
  66
  67
  68 template <typename Range, closure_selector Closure = closure<Range>::value>
  69 struct range_iterator_end
  70 {
  71     static inline typename range_iterator_type<Range, Closure>::type
  72     apply(Range& range)
  73     {
  74         return boost::end(range);
  75     }
  76 };
  77
  78 template <typename Range>
  79 struct range_iterator_end<Range, open>
  80 {
  81     static inline typename range_iterator_type<Range, open>::type
  82     apply(Range& range)
  83     {
  84         return closing_iterator<Range>(range, true);
  85     }
  86 };
  87
  88
  89
  90
  91
  92
  93 template <typename Range, typename Value, typename Reference = Value>
  94 class range_segment_iterator
  95     : public boost::iterator_facade
  96         <
  97             range_segment_iterator<Range, Value, Reference>,
  98             Value,
  99             boost::bidirectional_traversal_tag,
 100             Reference
 101         >
 102 {
 103     static inline bool has_less_than_two_elements(Range const& r)
 104     {
 105         return boost::size(r) < ((closure<Range>::value == open) ? 1u : 2u);
 106     }
 107
 108 public:
 109     typedef typename range_iterator_type<Range>::type iterator_type;
 110
 111     // default constructor
 112     range_segment_iterator()
 113         : m_it(), m_has_less_than_two_elements(false)
 114     {}
 115
 116     // for begin
 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))
 120     {}
 121
 122     // for end
 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))
 126     {
 127         if (! m_has_less_than_two_elements)
 128         {
 129             // the range consists of at least two items
 130             --m_it;
 131         }
 132     }
 133
 134     template
 135     <
 136         typename OtherRange,
 137         typename OtherValue,
 138         typename OtherReference
 139     >
 140     range_segment_iterator(range_segment_iterator
 141                            <
 142                                OtherRange,
 143                                OtherValue,
 144                                OtherReference
 145                            > const& other)
 146         : m_it(other.m_it)
 147     {
 148         typedef typename range_segment_iterator
 149             <
 150                 OtherRange, OtherValue, OtherReference
 151             >::iterator_type other_iterator_type;
 152
 153         static const bool are_conv
 154             = boost::is_convertible<other_iterator_type, iterator_type>::value;
 155
 156         BOOST_MPL_ASSERT_MSG((are_conv), NOT_CONVERTIBLE, (types<OtherRange>));
 157     }
 158
 159 private:
 160     friend class boost::iterator_core_access;
 161
 162     template <typename Rng, typename V, typename R>
 163     friend class range_segment_iterator;
 164
 165     inline Reference dereference() const
 166     {
 167         if (m_has_less_than_two_elements)
 168         {
 169             return Reference(*m_it, *m_it);
 170         }
 171
 172         iterator_type next(m_it);
 173         ++next;
 174         return Reference(*m_it, *next);
 175     }
 176
 177     template
 178     <
 179         typename OtherRange,
 180         typename OtherValue,
 181         typename OtherReference
 182     >
 183     inline bool equal(range_segment_iterator
 184                       <
 185                           OtherRange,
 186                           OtherValue,
 187                           OtherReference
 188                       > const& other) const
 189     {
 190         return m_it == other.m_it;
 191     }
 192
 193     inline void increment()
 194     {
 195         ++m_it;
 196     }
 197
 198     inline void decrement()
 199     {
 200         --m_it;
 201     }
 202
 203 private:
 204     iterator_type m_it;
 205     bool m_has_less_than_two_elements;
 206 };
 207
 208
 209 }} // namespace detail::segment_iterator
 210 #endif // DOXYGEN_NO_DETAIL
 211
 212 }} // namespace boost::geometry
 213
 214
 215 #endif // BOOST_GEOMETRY_ITERATORS_DETAIL_SEGMENT_ITERATOR_RANGE_SEGMENT_ITERATOR_HPP