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

   1 // Boost.Geometry (aka GGL, Generic Geometry Library)
   2
   3 // Copyright (c) 2014-2020, Oracle and/or its affiliates.
   4
   5 // Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle
   6 // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
   7
   8 // Licensed under the Boost Software License version 1.0.
   9 // http://www.boost.org/users/license.html
  10
  11 #ifndef BOOST_GEOMETRY_ITERATORS_DETAIL_SEGMENT_ITERATOR_VALUE_TYPE_HPP
  12 #define BOOST_GEOMETRY_ITERATORS_DETAIL_SEGMENT_ITERATOR_VALUE_TYPE_HPP
  13
  14 #include <iterator>
  15
  16 #include <boost/geometry/geometries/segment.hpp>
  17 #include <boost/geometry/geometries/pointing_segment.hpp>
  18 #include <boost/geometry/iterators/point_iterator.hpp>
  19 #include <boost/geometry/util/type_traits_std.hpp>
  20
  21 namespace boost { namespace geometry
  22 {
  23
  24 #ifndef DOXYGEN_NO_DETAIL
  25 namespace detail { namespace segment_iterator
  26 {
  27
  28 template <typename Geometry>
  29 struct value_type
  30 {
  31     typedef typename std::iterator_traits
  32         <
  33             geometry::point_iterator<Geometry>
  34         >::reference point_iterator_reference_type;
  35
  36     typedef typename detail::point_iterator::value_type
  37         <
  38             Geometry
  39         >::type point_iterator_value_type;
  40
  41     // If the reference type of the point iterator is not really a
  42     // reference, then dereferencing a point iterator would create
  43     // a temporary object.
  44     // In this case using a pointing_segment to represent the
  45     // dereferenced value of the segment iterator cannot be used, as
  46     // it would store pointers to temporary objects. Instead we use a
  47     // segment, which does a full copy of the temporary objects
  48     // returned by the point iterator.
  49     typedef std::conditional_t
  50         <
  51             std::is_reference<point_iterator_reference_type>::value,
  52             geometry::model::pointing_segment<point_iterator_value_type>,
  53             geometry::model::segment
  54                 <
  55                     typename util::remove_cptrref
  56                         <
  57                             point_iterator_value_type
  58                         >::type
  59                 >
  60         > type;
  61 };
  62
  63 }} // namespace detail::segment_iterator
  64 #endif // DOXYGEN_NO_DETAIL
  65
  66 }} // namespace boost::geometry
  67
  68 #endif // BOOST_GEOMETRY_ITERATORS_DETAIL_SEGMENT_ITERATOR_VALUE_TYPE_HPP