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// Boost.Geometry (aka GGL, Generic Geometry Library)
// Copyright (c) 2007-2012 Barend Gehrels, Amsterdam, the Netherlands.
// Use, modification and distribution is subject to the Boost Software License,
// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
#ifndef BOOST_GEOMETRY_ALGORITHMS_DETAIL_OVERLAY_GET_RING_HPP
#define BOOST_GEOMETRY_ALGORITHMS_DETAIL_OVERLAY_GET_RING_HPP
#include <boost/assert.hpp>
#include <boost/range.hpp>
#include <boost/geometry/core/exterior_ring.hpp>
#include <boost/geometry/core/interior_rings.hpp>
#include <boost/geometry/core/ring_type.hpp>
#include <boost/geometry/core/tags.hpp>
#include <boost/geometry/algorithms/detail/ring_identifier.hpp>
#include <boost/geometry/geometries/concepts/check.hpp>
#include <boost/geometry/util/range.hpp>
namespace boost { namespace geometry
{
#ifndef DOXYGEN_NO_DETAIL
namespace detail { namespace overlay
{
template<typename Tag>
struct get_ring
{};
// A range of rings (multi-ring but that does not exist)
// gets the "void" tag and is dispatched here.
template<>
struct get_ring<void>
{
template<typename Range>
static inline typename boost::range_value<Range>::type const&
apply(ring_identifier const& id, Range const& container)
{
return range::at(container, id.multi_index);
}
};
template<>
struct get_ring<ring_tag>
{
template<typename Ring>
static inline Ring const& apply(ring_identifier const& , Ring const& ring)
{
return ring;
}
};
template<>
struct get_ring<box_tag>
{
template<typename Box>
static inline Box const& apply(ring_identifier const& ,
Box const& box)
{
return box;
}
};
template<>
struct get_ring<polygon_tag>
{
template<typename Polygon>
static inline typename ring_return_type<Polygon const>::type const apply(
ring_identifier const& id,
Polygon const& polygon)
{
BOOST_ASSERT
(
id.ring_index >= -1
&& id.ring_index < int(boost::size(interior_rings(polygon)))
);
return id.ring_index < 0
? exterior_ring(polygon)
: range::at(interior_rings(polygon), id.ring_index);
}
};
template<>
struct get_ring<multi_polygon_tag>
{
template<typename MultiPolygon>
static inline typename ring_type<MultiPolygon>::type const& apply(
ring_identifier const& id,
MultiPolygon const& multi_polygon)
{
BOOST_ASSERT
(
id.multi_index >= 0
&& id.multi_index < int(boost::size(multi_polygon))
);
return get_ring<polygon_tag>::apply(id,
range::at(multi_polygon, id.multi_index));
}
};
}} // namespace detail::overlay
#endif // DOXYGEN_NO_DETAIL
}} // namespace boost::geometry
#endif // BOOST_GEOMETRY_ALGORITHMS_DETAIL_OVERLAY_GET_RING_HPP
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