ceph/src/boost/libs/geometry/include/boost/geometry/iterators/detail/segment_iterator/value_type.hpp

   1 // Boost.Geometry (aka GGL, Generic Geometry Library)
   2
   3 // Copyright (c) 2014-2015, 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_VALUE_TYPE_HPP
  11 #define BOOST_GEOMETRY_ITERATORS_DETAIL_SEGMENT_ITERATOR_VALUE_TYPE_HPP
  12
  13 #include <iterator>
  14
  15 #include <boost/mpl/if.hpp>
  16 #include <boost/type_traits/is_reference.hpp>
  17
  18 #include <boost/geometry/iterators/point_iterator.hpp>
  19 #include <boost/geometry/util/bare_type.hpp>
  20 #include <boost/geometry/geometries/segment.hpp>
  21 #include <boost/geometry/geometries/pointing_segment.hpp>
  22
  23
  24 namespace boost { namespace geometry
  25 {
  26
  27 #ifndef DOXYGEN_NO_DETAIL
  28 namespace detail { namespace segment_iterator
  29 {
  30
  31 template <typename Geometry>
  32 struct value_type
  33 {
  34     typedef typename std::iterator_traits
  35         <
  36             geometry::point_iterator<Geometry>
  37         >::reference point_iterator_reference_type;
  38
  39     typedef typename detail::point_iterator::value_type
  40         <
  41             Geometry
  42         >::type point_iterator_value_type;
  43
  44     // If the reference type of the point iterator is not really a
  45     // reference, then dereferencing a point iterator would create
  46     // a temporary object.
  47     // In this case using a pointing_segment to represent the
  48     // dereferenced value of the segment iterator cannot be used, as
  49     // it would store pointers to temporary objects. Instead we use a
  50     // segment, which does a full copy of the temporary objects
  51     // returned by the point iterator.
  52     typedef typename boost::mpl::if_
  53         <
  54             boost::is_reference<point_iterator_reference_type>,
  55             geometry::model::pointing_segment<point_iterator_value_type>,
  56             geometry::model::segment
  57                 <
  58                     typename geometry::util::bare_type
  59                         <
  60                             point_iterator_value_type
  61                         >::type
  62                 >
  63         >::type type;
  64 };
  65
  66 }} // namespace detail::segment_iterator
  67 #endif // DOXYGEN_NO_DETAIL
  68
  69 }} // namespace boost::geometry
  70
  71 #endif // BOOST_GEOMETRY_ITERATORS_DETAIL_SEGMENT_ITERATOR_VALUE_TYPE_HPP