ceph/src/boost/libs/geometry/include/boost/geometry/core/tag.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_CORE_TAG_HPP
  15 #define BOOST_GEOMETRY_CORE_TAG_HPP
  16
  17
  18 #include <boost/geometry/core/tags.hpp>
  19 #include <boost/geometry/util/bare_type.hpp>
  20
  21
  22 namespace boost { namespace geometry
  23 {
  24
  25 namespace traits
  26 {
  27
  28 /*!
  29 \brief Traits class to attach a tag to a geometry
  30 \details All geometries should implement a traits::tag<G>::type metafunction to indicate their
  31     own geometry type.
  32 \ingroup traits
  33 \par Geometries:
  34     - all geometries
  35 \par Specializations should provide:
  36     - typedef XXX_tag type; (point_tag, box_tag, ...)
  37 \tparam Geometry geometry
  38 */
  39 template <typename Geometry, typename Enable = void>
  40 struct tag
  41 {
  42     typedef void type;
  43 };
  44
  45 } // namespace traits
  46
  47
  48
  49 /*!
  50 \brief \brief_meta{type, tag, \meta_geometry_type}
  51 \details With Boost.Geometry, tags are the driving force of the tag dispatching
  52     mechanism. The tag metafunction is therefore used in every free function.
  53 \tparam Geometry \tparam_geometry
  54 \ingroup core
  55
  56 \qbk{[include reference/core/tag.qbk]}
  57 */
  58 template <typename Geometry>
  59 struct tag
  60 {
  61     typedef typename traits::tag
  62         <
  63             typename geometry::util::bare_type<Geometry>::type
  64         >::type type;
  65 };
  66
  67 }} // namespace boost::geometry
  68
  69 #endif // BOOST_GEOMETRY_CORE_TAG_HPP