ceph/src/boost/libs/geometry/include/boost/geometry/strategies/cartesian/centroid_average.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 // This file was modified by Oracle on 2015.
   8 // Modifications copyright (c) 2015 Oracle and/or its affiliates.
   9
  10 // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
  11
  12 // Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
  13 // (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands.
  14
  15 // Use, modification and distribution is subject to the Boost Software License,
  16 // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
  17 // http://www.boost.org/LICENSE_1_0.txt)
  18
  19 #ifndef BOOST_GEOMETRY_STRATEGIES_CARTESIAN_CENTROID_AVERAGE_HPP
  20 #define BOOST_GEOMETRY_STRATEGIES_CARTESIAN_CENTROID_AVERAGE_HPP
  21
  22
  23 #include <cstddef>
  24
  25 #include <boost/geometry/algorithms/assign.hpp>
  26 #include <boost/geometry/arithmetic/arithmetic.hpp>
  27 #include <boost/geometry/core/coordinate_type.hpp>
  28 #include <boost/geometry/core/point_type.hpp>
  29 #include <boost/geometry/strategies/centroid.hpp>
  30
  31
  32 namespace boost { namespace geometry
  33 {
  34
  35 namespace strategy { namespace centroid
  36 {
  37
  38
  39 /*!
  40 \brief Centroid calculation taking average of points
  41 \ingroup strategies
  42 */
  43 template
  44 <
  45     typename PointCentroid,
  46     typename Point = PointCentroid
  47 >
  48 class average
  49 {
  50 private :
  51
  52     /*! subclass to keep state */
  53     class sum
  54     {
  55         friend class average;
  56         std::size_t count;
  57         PointCentroid centroid;
  58
  59     public :
  60         inline sum()
  61             : count(0)
  62         {
  63             assign_zero(centroid);
  64         }
  65     };
  66
  67 public :
  68     typedef sum state_type;
  69     typedef PointCentroid centroid_point_type;
  70     typedef Point point_type;
  71
  72     static inline void apply(Point const& p, sum& state)
  73     {
  74         add_point(state.centroid, p);
  75         state.count++;
  76     }
  77
  78     static inline bool result(sum const& state, PointCentroid& centroid)
  79     {
  80         centroid = state.centroid;
  81         if ( state.count > 0 )
  82         {
  83             divide_value(centroid, state.count);
  84             return true;
  85         }
  86         return false;
  87     }
  88
  89 };
  90
  91
  92 #ifndef DOXYGEN_NO_STRATEGY_SPECIALIZATIONS
  93
  94
  95 namespace services
  96 {
  97
  98 template <typename Point, std::size_t DimensionCount, typename Geometry>
  99 struct default_strategy
 100 <
 101     cartesian_tag,
 102     pointlike_tag,
 103     DimensionCount,
 104     Point,
 105     Geometry
 106 >
 107 {
 108     typedef average
 109         <
 110             Point,
 111             typename point_type<Geometry>::type
 112         > type;
 113 };
 114
 115 } // namespace services
 116
 117 #endif
 118
 119
 120 }} // namespace strategy::centroid
 121
 122
 123 }} // namespace boost::geometry
 124
 125
 126 #endif // BOOST_GEOMETRY_STRATEGIES_CARTESIAN_CENTROID_AVERAGE_HPP