ceph/src/boost/boost/geometry/views/box_view.hpp

   1 // Boost.Geometry (aka GGL, Generic Geometry Library)
   2
   3 // Copyright (c) 2007-2012 Barend Gehrels, Amsterdam, the Netherlands.
   4 // Copyright (c) 2008-2012 Bruno Lalande, Paris, France.
   5 // Copyright (c) 2009-2012 Mateusz Loskot, London, UK.
   6
   7 // Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
   8 // (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands.
   9
  10 // Use, modification and distribution is subject to the Boost Software License,
  11 // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
  12 // http://www.boost.org/LICENSE_1_0.txt)
  13
  14 #ifndef BOOST_GEOMETRY_VIEWS_BOX_VIEW_HPP
  15 #define BOOST_GEOMETRY_VIEWS_BOX_VIEW_HPP
  16
  17
  18 #include <boost/range.hpp>
  19
  20 #include <boost/geometry/core/point_type.hpp>
  21 #include <boost/geometry/views/detail/points_view.hpp>
  22 #include <boost/geometry/algorithms/assign.hpp>
  23
  24
  25 namespace boost { namespace geometry
  26 {
  27
  28
  29 /*!
  30 \brief Makes a box behave like a ring or a range
  31 \details Adapts a box to the Boost.Range concept, enabling the user to iterating
  32     box corners. The box_view is registered as a Ring Concept
  33 \tparam Box \tparam_geometry{Box}
  34 \tparam Clockwise If true, walks in clockwise direction, otherwise
  35     it walks in counterclockwise direction
  36 \ingroup views
  37
  38 \qbk{before.synopsis,
  39 [heading Model of]
  40 [link geometry.reference.concepts.concept_ring Ring Concept]
  41 }
  42
  43 \qbk{[include reference/views/box_view.qbk]}
  44 */
  45 template <typename Box, bool Clockwise = true>
  46 struct box_view
  47     : public detail::points_view
  48         <
  49             typename geometry::point_type<Box>::type,
  50             5
  51         >
  52 {
  53     typedef typename geometry::point_type<Box>::type point_type;
  54
  55     /// Constructor accepting the box to adapt
  56     explicit box_view(Box const& box)
  57         : detail::points_view<point_type, 5>(copy_policy(box))
  58     {}
  59
  60 private :
  61
  62     class copy_policy
  63     {
  64     public :
  65         inline copy_policy(Box const& box)
  66             : m_box(box)
  67         {}
  68
  69         inline void apply(point_type* points) const
  70         {
  71             // assign_box_corners_oriented requires a range
  72             // an alternative for this workaround would be to pass a range here,
  73             // e.g. use boost::array in points_view instead of c-array
  74             std::pair<point_type*, point_type*> rng = std::make_pair(points, points + 5);
  75             detail::assign_box_corners_oriented<!Clockwise>(m_box, rng);
  76             points[4] = points[0];
  77         }
  78     private :
  79         Box const& m_box;
  80     };
  81
  82 };
  83
  84
  85 #ifndef DOXYGEN_NO_TRAITS_SPECIALIZATIONS
  86
  87 // All views on boxes are handled as rings
  88 namespace traits
  89 {
  90
  91 template<typename Box, bool Clockwise>
  92 struct tag<box_view<Box, Clockwise> >
  93 {
  94     typedef ring_tag type;
  95 };
  96
  97 template<typename Box>
  98 struct point_order<box_view<Box, false> >
  99 {
 100     static order_selector const value = counterclockwise;
 101 };
 102
 103
 104 template<typename Box>
 105 struct point_order<box_view<Box, true> >
 106 {
 107     static order_selector const value = clockwise;
 108 };
 109
 110 }
 111
 112 #endif // DOXYGEN_NO_TRAITS_SPECIALIZATIONS
 113
 114
 115 }} // namespace boost::geometry
 116
 117
 118 #endif // BOOST_GEOMETRY_VIEWS_BOX_VIEW_HPP