ceph/src/boost/boost/geometry/strategies/area_result.hpp

   1 // Boost.Geometry
   2
   3 // Copyright (c) 2017 Adam Wulkiewicz, Lodz, Poland.
   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_STRATEGIES_AREA_RESULT_HPP
  10 #define BOOST_GEOMETRY_STRATEGIES_AREA_RESULT_HPP
  11
  12
  13 #include <boost/geometry/core/coordinate_type.hpp>
  14 #include <boost/geometry/core/cs.hpp>
  15
  16 #include <boost/geometry/strategies/area.hpp>
  17 #include <boost/geometry/strategies/default_strategy.hpp>
  18
  19 #include <boost/geometry/util/select_most_precise.hpp>
  20 #include <boost/geometry/util/select_sequence_element.hpp>
  21
  22
  23 #include <boost/mpl/if.hpp>
  24 #include <boost/type_traits/is_same.hpp>
  25 #include <boost/variant/variant_fwd.hpp>
  26
  27
  28 namespace boost { namespace geometry
  29 {
  30
  31
  32 /*!
  33 \brief Meta-function defining return type of area function
  34 \ingroup area
  35 \note The return-type is defined by Geometry and Strategy
  36  */
  37 template
  38 <
  39     typename Geometry,
  40     typename Strategy = default_strategy
  41 >
  42 struct area_result
  43     : Strategy::template result_type<Geometry>
  44 {};
  45
  46 template <BOOST_VARIANT_ENUM_PARAMS(typename T), typename Strategy>
  47 struct area_result<boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>, Strategy>
  48     : geometry::area_result
  49         <
  50             typename geometry::util::select_sequence_element
  51                 <
  52                     typename boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>::types
  53                 >::type,
  54             Strategy
  55         >
  56 {};
  57
  58 template <typename Geometry>
  59 struct area_result<Geometry, default_strategy>
  60     : geometry::area_result
  61         <
  62             Geometry,
  63             typename geometry::strategy::area::services::default_strategy
  64                 <
  65                     typename cs_tag<Geometry>::type
  66                 >::type
  67         >
  68 {};
  69
  70 #ifndef DOXYGEN_NO_DETAIL
  71 namespace detail { namespace area
  72 {
  73
  74 template <typename Curr, typename Next>
  75 struct pred_more_precise_default_area_result
  76 {
  77     typedef typename geometry::area_result<Curr, default_strategy>::type curr_result_t;
  78     typedef typename geometry::area_result<Next, default_strategy>::type next_result_t;
  79
  80     typedef typename boost::mpl::if_c
  81         <
  82             boost::is_same
  83                 <
  84                     curr_result_t,
  85                     typename geometry::select_most_precise
  86                         <
  87                             curr_result_t,
  88                             next_result_t
  89                         >::type
  90                 >::value,
  91             Curr,
  92             Next
  93         >::type type;
  94 };
  95
  96 }} // namespace detail::area
  97 #endif //DOXYGEN_NO_DETAIL
  98
  99 template <BOOST_VARIANT_ENUM_PARAMS(typename T)>
 100 struct area_result<boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>, default_strategy>
 101     : geometry::area_result
 102         <
 103             typename geometry::util::select_sequence_element
 104                 <
 105                     typename boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>::types,
 106                     geometry::detail::area::pred_more_precise_default_area_result
 107                 >::type,
 108             default_strategy
 109         >
 110 {};
 111
 112
 113 }} // namespace boost::geometry
 114
 115
 116 #endif // BOOST_GEOMETRY_STRATEGIES_AREA_RESULT_HPP