ceph/src/boost/boost/geometry/algorithms/detail/overlay/needs_self_turns.hpp

   1 // Boost.Geometry (aka GGL, Generic Geometry Library)
   2
   3 // Copyright (c) 2017-2017 Barend Gehrels, Amsterdam, the Netherlands.
   4
   5 // Use, modification and distribution is subject to the Boost Software License,
   6 // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
   7 // http://www.boost.org/LICENSE_1_0.txt)
   8
   9 #ifndef BOOST_GEOMETRY_ALGORITHMS_DETAIL_OVERLAY_NEEDS_SELF_TURNS_HPP
  10 #define BOOST_GEOMETRY_ALGORITHMS_DETAIL_OVERLAY_NEEDS_SELF_TURNS_HPP
  11
  12 #include <boost/range.hpp>
  13
  14 #include <boost/geometry/core/tags.hpp>
  15 #include <boost/geometry/algorithms/num_interior_rings.hpp>
  16
  17
  18 namespace boost { namespace geometry
  19 {
  20
  21
  22 #ifndef DOXYGEN_NO_DETAIL
  23 namespace detail { namespace overlay
  24 {
  25
  26 template
  27 <
  28     typename Geometry,
  29     typename Tag = typename tag<Geometry>::type
  30 >
  31 struct needs_self_turns
  32 {
  33 };
  34
  35 template <typename Geometry>
  36 struct needs_self_turns<Geometry, box_tag>
  37 {
  38     static inline bool apply(Geometry const&)
  39     {
  40         return false;
  41     }
  42 };
  43
  44 template <typename Geometry>
  45 struct needs_self_turns<Geometry, ring_tag>
  46 {
  47     static inline bool apply(Geometry const&)
  48     {
  49         return false;
  50     }
  51 };
  52
  53 template <typename Geometry>
  54 struct needs_self_turns<Geometry, polygon_tag>
  55 {
  56     static inline bool apply(Geometry const& polygon)
  57     {
  58         return geometry::num_interior_rings(polygon) > 0;
  59     }
  60 };
  61
  62 template <typename Geometry>
  63 struct needs_self_turns<Geometry, multi_polygon_tag>
  64 {
  65     static inline bool apply(Geometry const& multi)
  66     {
  67         typedef typename boost::range_value<Geometry>::type polygon_type;
  68         std::size_t const n = boost::size(multi);
  69         return n > 1 || (n == 1
  70              && needs_self_turns<polygon_type>
  71                          ::apply(*boost::begin(multi)));
  72     }
  73 };
  74
  75
  76 }} // namespace detail::overlay
  77 #endif // DOXYGEN_NO_DETAIL
  78
  79
  80 }} // namespace boost::geometry
  81
  82
  83 #endif // BOOST_GEOMETRY_ALGORITHMS_DETAIL_OVERLAY_NEEDS_SELF_TURNS_HPP