// Boost.Geometry (aka GGL, Generic Geometry Library) // Copyright (c) 2015-2020, Oracle and/or its affiliates. // Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle // Licensed under the Boost Software License version 1.0. // http://www.boost.org/users/license.html #ifndef BOOST_GEOMETRY_ALGORITHMS_IS_EMPTY_HPP #define BOOST_GEOMETRY_ALGORITHMS_IS_EMPTY_HPP #include <boost/range/begin.hpp> #include <boost/range/empty.hpp> #include <boost/range/end.hpp> #include <boost/variant/apply_visitor.hpp> #include <boost/variant/static_visitor.hpp> #include <boost/variant/variant_fwd.hpp> #include <boost/geometry/core/exterior_ring.hpp> #include <boost/geometry/core/interior_rings.hpp> #include <boost/geometry/core/tag.hpp> #include <boost/geometry/core/tags.hpp> #include <boost/geometry/algorithms/not_implemented.hpp> #include <boost/geometry/algorithms/detail/check_iterator_range.hpp> #include <boost/geometry/geometries/concepts/check.hpp> namespace boost { namespace geometry { #ifndef DOXYGEN_NO_DETAIL namespace detail { namespace is_empty { struct always_not_empty { template <typename Geometry> static inline bool apply(Geometry const&) { return false; } }; struct range_is_empty { template <typename Range> static inline bool apply(Range const& range) { return boost::empty(range); } }; class polygon_is_empty { template <typename InteriorRings> static inline bool check_interior_rings(InteriorRings const& interior_rings) { return check_iterator_range < range_is_empty, true // allow empty range >::apply(boost::begin(interior_rings), boost::end(interior_rings)); } public: template <typename Polygon> static inline bool apply(Polygon const& polygon) { return boost::empty(exterior_ring(polygon)) && check_interior_rings(interior_rings(polygon)); } }; template <typename Policy = range_is_empty> struct multi_is_empty { template <typename MultiGeometry> static inline bool apply(MultiGeometry const& multigeometry) { return check_iterator_range < Policy, true // allow empty range >::apply(boost::begin(multigeometry), boost::end(multigeometry)); } }; }} // namespace detail::is_empty #endif // DOXYGEN_NO_DETAIL #ifndef DOXYGEN_NO_DISPATCH namespace dispatch { template <typename Geometry, typename Tag = typename tag<Geometry>::type> struct is_empty : not_implemented<Tag> {}; template <typename Geometry> struct is_empty<Geometry, point_tag> : detail::is_empty::always_not_empty {}; template <typename Geometry> struct is_empty<Geometry, box_tag> : detail::is_empty::always_not_empty {}; template <typename Geometry> struct is_empty<Geometry, segment_tag> : detail::is_empty::always_not_empty {}; template <typename Geometry> struct is_empty<Geometry, linestring_tag> : detail::is_empty::range_is_empty {}; template <typename Geometry> struct is_empty<Geometry, ring_tag> : detail::is_empty::range_is_empty {}; template <typename Geometry> struct is_empty<Geometry, polygon_tag> : detail::is_empty::polygon_is_empty {}; template <typename Geometry> struct is_empty<Geometry, multi_point_tag> : detail::is_empty::range_is_empty {}; template <typename Geometry> struct is_empty<Geometry, multi_linestring_tag> : detail::is_empty::multi_is_empty<> {}; template <typename Geometry> struct is_empty<Geometry, multi_polygon_tag> : detail::is_empty::multi_is_empty<detail::is_empty::polygon_is_empty> {}; } // namespace dispatch #endif // DOXYGEN_NO_DISPATCH namespace resolve_variant { template <typename Geometry> struct is_empty { static inline bool apply(Geometry const& geometry) { concepts::check<Geometry const>(); return dispatch::is_empty<Geometry>::apply(geometry); } }; template <BOOST_VARIANT_ENUM_PARAMS(typename T)> struct is_empty<boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)> > { struct visitor : boost::static_visitor<bool> { template <typename Geometry> inline bool operator()(Geometry const& geometry) const { return is_empty<Geometry>::apply(geometry); } }; static bool apply(boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)> const& geometry) { return boost::apply_visitor(visitor(), geometry); } }; } // namespace resolve_variant /*! \brief \brief_check{is the empty set} \ingroup is_empty \tparam Geometry \tparam_geometry \param geometry \param_geometry \return \return_check{is the empty set} \qbk{[include reference/algorithms/is_empty.qbk]} */ template <typename Geometry> inline bool is_empty(Geometry const& geometry) { return resolve_variant::is_empty<Geometry>::apply(geometry); } }} // namespace boost::geometry #endif // BOOST_GEOMETRY_ALGORITHMS_IS_EMPTY_HPP