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) 2014-2020, Oracle and/or its affiliates.
   4 // Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle
   5 // Contributed and/or modified by Adam Wulkiewicz, 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
  14 #include <type_traits>
  15
  16 #include <boost/iterator/iterator_facade.hpp>
  17 #include <boost/iterator/iterator_categories.hpp>
  18 #include <boost/range/begin.hpp>
  19 #include <boost/range/end.hpp>
  20 #include <boost/range/size.hpp>
  21
  22 #include <boost/geometry/core/closure.hpp>
  23 #include <boost/geometry/core/static_assert.hpp>
  24 #include <boost/geometry/iterators/closing_iterator.hpp>
  25
  26
  27 namespace boost { namespace geometry
  28 {
  29
  30 #ifndef DOXYGEN_NO_DETAIL
  31 namespace detail { namespace segment_iterator
  32 {
  33
  34
  35 template <typename Range, closure_selector Closure = closure<Range>::value>
  36 struct range_iterator_type
  37 {
  38     typedef typename boost::range_iterator<Range>::type type;
  39 };
  40
  41 template <typename Range>
  42 struct range_iterator_type<Range, open>
  43 {
  44     typedef closing_iterator<Range> type;
  45 };
  46
  47
  48
  49 template <typename Range, closure_selector Closure = closure<Range>::value>
  50 struct range_iterator_begin
  51 {
  52     static inline typename range_iterator_type<Range, Closure>::type
  53     apply(Range& range)
  54     {
  55         return boost::begin(range);
  56     }
  57 };
  58
  59 template <typename Range>
  60 struct range_iterator_begin<Range, open>
  61 {
  62     static inline typename range_iterator_type<Range, open>::type
  63     apply(Range& range)
  64     {
  65         return closing_iterator<Range>(range);
  66     }
  67 };
  68
  69
  70
  71 template <typename Range, closure_selector Closure = closure<Range>::value>
  72 struct range_iterator_end
  73 {
  74     static inline typename range_iterator_type<Range, Closure>::type
  75     apply(Range& range)
  76     {
  77         return boost::end(range);
  78     }
  79 };
  80
  81 template <typename Range>
  82 struct range_iterator_end<Range, open>
  83 {
  84     static inline typename range_iterator_type<Range, open>::type
  85     apply(Range& range)
  86     {
  87         return closing_iterator<Range>(range, true);
  88     }
  89 };
  90
  91
  92
  93
  94
  95
  96 template <typename Range, typename Value, typename Reference = Value>
  97 class range_segment_iterator
  98     : public boost::iterator_facade
  99         <
 100             range_segment_iterator<Range, Value, Reference>,
 101             Value,
 102             boost::bidirectional_traversal_tag,
 103             Reference
 104         >
 105 {
 106     static inline bool has_less_than_two_elements(Range const& r)
 107     {
 108         return boost::size(r) < ((closure<Range>::value == open) ? 1u : 2u);
 109     }
 110
 111 public:
 112     typedef typename range_iterator_type<Range>::type iterator_type;
 113
 114     // default constructor
 115     range_segment_iterator()
 116         : m_it(), m_has_less_than_two_elements(false)
 117     {}
 118
 119     // for begin
 120     range_segment_iterator(Range& r)
 121         : m_it(range_iterator_begin<Range>::apply(r))
 122         , m_has_less_than_two_elements(has_less_than_two_elements(r))
 123     {}
 124
 125     // for end
 126     range_segment_iterator(Range& r, bool)
 127         : m_it(range_iterator_end<Range>::apply(r))
 128         , m_has_less_than_two_elements(has_less_than_two_elements(r))
 129     {
 130         if (! m_has_less_than_two_elements)
 131         {
 132             // the range consists of at least two items
 133             --m_it;
 134         }
 135     }
 136
 137     template
 138     <
 139         typename OtherRange,
 140         typename OtherValue,
 141         typename OtherReference
 142     >
 143     range_segment_iterator(range_segment_iterator
 144                            <
 145                                OtherRange,
 146                                OtherValue,
 147                                OtherReference
 148                            > const& other)
 149         : m_it(other.m_it)
 150     {
 151         typedef typename range_segment_iterator
 152             <
 153                 OtherRange, OtherValue, OtherReference
 154             >::iterator_type other_iterator_type;
 155
 156         static const bool are_conv
 157             = std::is_convertible<other_iterator_type, iterator_type>::value;
 158
 159         BOOST_GEOMETRY_STATIC_ASSERT((are_conv),
 160             "Other iterator has to be convertible to member iterator.",
 161             OtherRange);
 162     }
 163
 164 private:
 165     friend class boost::iterator_core_access;
 166
 167     template <typename Rng, typename V, typename R>
 168     friend class range_segment_iterator;
 169
 170     inline Reference dereference() const
 171     {
 172         if (m_has_less_than_two_elements)
 173         {
 174             return Reference(*m_it, *m_it);
 175         }
 176
 177         iterator_type next(m_it);
 178         ++next;
 179         return Reference(*m_it, *next);
 180     }
 181
 182     template
 183     <
 184         typename OtherRange,
 185         typename OtherValue,
 186         typename OtherReference
 187     >
 188     inline bool equal(range_segment_iterator
 189                       <
 190                           OtherRange,
 191                           OtherValue,
 192                           OtherReference
 193                       > const& other) const
 194     {
 195         return m_it == other.m_it;
 196     }
 197
 198     inline void increment()
 199     {
 200         ++m_it;
 201     }
 202
 203     inline void decrement()
 204     {
 205         --m_it;
 206     }
 207
 208 private:
 209     iterator_type m_it;
 210     bool m_has_less_than_two_elements;
 211 };
 212
 213
 214 }} // namespace detail::segment_iterator
 215 #endif // DOXYGEN_NO_DETAIL
 216
 217 }} // namespace boost::geometry
 218
 219
 220 #endif // BOOST_GEOMETRY_ITERATORS_DETAIL_SEGMENT_ITERATOR_RANGE_SEGMENT_ITERATOR_HPP