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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 |