ceph/src/boost/boost/geometry/algorithms/detail/is_valid/segment.hpp

   1 // Boost.Geometry (aka GGL, Generic Geometry Library)
   2
   3 // Copyright (c) 2014-2017, 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_ALGORITHMS_DETAIL_IS_VALID_SEGMENT_HPP
  12 #define BOOST_GEOMETRY_ALGORITHMS_DETAIL_IS_VALID_SEGMENT_HPP
  13
  14 #include <boost/core/ignore_unused.hpp>
  15
  16 #include <boost/geometry/core/point_type.hpp>
  17 #include <boost/geometry/core/tags.hpp>
  18
  19 #include <boost/geometry/algorithms/assign.hpp>
  20 #include <boost/geometry/algorithms/equals.hpp>
  21 #include <boost/geometry/algorithms/validity_failure_type.hpp>
  22 #include <boost/geometry/algorithms/detail/is_valid/has_invalid_coordinate.hpp>
  23 #include <boost/geometry/algorithms/dispatch/is_valid.hpp>
  24
  25
  26 namespace boost { namespace geometry
  27 {
  28
  29
  30
  31 #ifndef DOXYGEN_NO_DISPATCH
  32 namespace dispatch
  33 {
  34
  35
  36 // A segment is a curve.
  37 // A curve is simple if it does not pass through the same point twice,
  38 // with the possible exception of its two endpoints
  39 // A curve is 1-dimensional, hence we have to check is the two
  40 // endpoints of the segment coincide, since in this case it is
  41 // 0-dimensional.
  42 //
  43 // Reference: OGC 06-103r4 (6.1.6.1)
  44 template <typename Segment>
  45 struct is_valid<Segment, segment_tag>
  46 {
  47     template <typename VisitPolicy, typename Strategy>
  48     static inline bool apply(Segment const& segment, VisitPolicy& visitor, Strategy const&)
  49     {
  50         boost::ignore_unused(visitor);
  51
  52         typename point_type<Segment>::type p[2];
  53         detail::assign_point_from_index<0>(segment, p[0]);
  54         detail::assign_point_from_index<1>(segment, p[1]);
  55
  56         if (detail::is_valid::has_invalid_coordinate
  57                 <
  58                     Segment
  59                 >::apply(segment, visitor))
  60         {
  61             return false;
  62         }
  63         else if (! geometry::equals(p[0], p[1]))
  64         {
  65             return visitor.template apply<no_failure>();
  66         }
  67         else
  68         {
  69             return
  70                 visitor.template apply<failure_wrong_topological_dimension>();
  71         }
  72     }
  73 };
  74
  75
  76 } // namespace dispatch
  77 #endif // DOXYGEN_NO_DISPATCH
  78
  79
  80 }} // namespace boost::geometry
  81
  82
  83 #endif // BOOST_GEOMETRY_ALGORITHMS_DETAIL_IS_VALID_SEGMENT_HPP