160 lines
4.2 KiB
C++
160 lines
4.2 KiB
C++
// Boost.Geometry (aka GGL, Generic Geometry Library)
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// Copyright (c) 2007-2011 Barend Gehrels, Amsterdam, the Netherlands.
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// Copyright (c) 2008-2011 Bruno Lalande, Paris, France.
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// Copyright (c) 2009-2011 Mateusz Loskot, London, UK.
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// Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
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// (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands.
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// Use, modification and distribution is subject to the Boost Software License,
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// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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#ifndef BOOST_GEOMETRY_ALGORITHMS_CLEAR_HPP
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#define BOOST_GEOMETRY_ALGORITHMS_CLEAR_HPP
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#include <boost/mpl/assert.hpp>
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#include <boost/type_traits/remove_const.hpp>
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#include <boost/geometry/core/access.hpp>
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#include <boost/geometry/core/exterior_ring.hpp>
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#include <boost/geometry/core/interior_rings.hpp>
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#include <boost/geometry/core/mutable_range.hpp>
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#include <boost/geometry/core/tag_cast.hpp>
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#include <boost/geometry/geometries/concepts/check.hpp>
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namespace boost { namespace geometry
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{
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#ifndef DOXYGEN_NO_DETAIL
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namespace detail { namespace clear
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{
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template <typename Geometry>
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struct collection_clear
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{
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static inline void apply(Geometry& geometry)
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{
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traits::clear<Geometry>::apply(geometry);
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}
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};
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template <typename Polygon>
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struct polygon_clear
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{
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static inline void apply(Polygon& polygon)
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{
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traits::clear
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<
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typename boost::remove_reference
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<
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typename traits::interior_mutable_type<Polygon>::type
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>::type
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>::apply(interior_rings(polygon));
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traits::clear
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<
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typename boost::remove_reference
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<
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typename traits::ring_mutable_type<Polygon>::type
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>::type
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>::apply(exterior_ring(polygon));
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}
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};
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template <typename Geometry>
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struct no_action
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{
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static inline void apply(Geometry& )
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{
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}
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};
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}} // namespace detail::clear
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#endif // DOXYGEN_NO_DETAIL
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#ifndef DOXYGEN_NO_DISPATCH
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namespace dispatch
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{
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template <typename Tag, typename Geometry>
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struct clear
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{
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BOOST_MPL_ASSERT_MSG
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(
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false, NOT_OR_NOT_YET_IMPLEMENTED_FOR_THIS_GEOMETRY_TYPE
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, (types<Geometry>)
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);
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};
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// Point/box/segment do not have clear. So specialize to do nothing.
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template <typename Geometry>
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struct clear<point_tag, Geometry>
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: detail::clear::no_action<Geometry>
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{};
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template <typename Geometry>
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struct clear<box_tag, Geometry>
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: detail::clear::no_action<Geometry>
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{};
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template <typename Geometry>
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struct clear<segment_tag, Geometry>
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: detail::clear::no_action<Geometry>
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{};
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template <typename Geometry>
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struct clear<linestring_tag, Geometry>
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: detail::clear::collection_clear<Geometry>
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{};
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template <typename Geometry>
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struct clear<ring_tag, Geometry>
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: detail::clear::collection_clear<Geometry>
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{};
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// Polygon can (indirectly) use std for clear
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template <typename Polygon>
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struct clear<polygon_tag, Polygon>
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: detail::clear::polygon_clear<Polygon>
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{};
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} // namespace dispatch
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#endif // DOXYGEN_NO_DISPATCH
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/*!
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\brief Clears a linestring, ring or polygon (exterior+interiors) or multi*
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\details Generic function to clear a geometry. All points will be removed from the collection or collections
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making up the geometry. In most cases this is equivalent to the .clear() method of a std::vector<...>. In
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the case of a polygon, this clear functionality is automatically called for the exterior ring, and for the
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interior ring collection. In the case of a point, boxes and segments, nothing will happen.
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\ingroup clear
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\tparam Geometry \tparam_geometry
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\param geometry \param_geometry which will be cleared
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\note points and boxes cannot be cleared, instead they can be set to zero by "assign_zero"
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\qbk{[include reference/algorithms/clear.qbk]}
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*/
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template <typename Geometry>
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inline void clear(Geometry& geometry)
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{
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concept::check<Geometry>();
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dispatch::clear
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<
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typename tag_cast<typename tag<Geometry>::type, multi_tag>::type,
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Geometry
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>::apply(geometry);
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}
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}} // namespace boost::geometry
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#endif // BOOST_GEOMETRY_ALGORITHMS_CLEAR_HPP
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