// Boost.Geometry (aka GGL, Generic Geometry Library)
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// Copyright (c) 2017-2017 Barend Gehrels, Amsterdam, the Netherlands.
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// This file was modified by Oracle on 2020.
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// Modifications copyright (c) 2020 Oracle and/or its affiliates.
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// Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
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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_DETAIL_OVERLAY_NEEDS_SELF_TURNS_HPP
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#define BOOST_GEOMETRY_ALGORITHMS_DETAIL_OVERLAY_NEEDS_SELF_TURNS_HPP
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#include <boost/range/begin.hpp>
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#include <boost/range/size.hpp>
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#include <boost/geometry/core/tags.hpp>
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#include <boost/geometry/algorithms/num_interior_rings.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 overlay
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{
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template
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<
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typename Geometry,
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typename Tag = typename tag<Geometry>::type
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>
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struct needs_self_turns
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{
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};
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template <typename Geometry>
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struct needs_self_turns<Geometry, box_tag>
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{
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static inline bool apply(Geometry const&)
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{
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return false;
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}
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};
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template <typename Geometry>
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struct needs_self_turns<Geometry, ring_tag>
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{
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static inline bool apply(Geometry const&)
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{
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return false;
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}
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};
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template <typename Geometry>
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struct needs_self_turns<Geometry, polygon_tag>
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{
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static inline bool apply(Geometry const& polygon)
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{
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return geometry::num_interior_rings(polygon) > 0;
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}
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};
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template <typename Geometry>
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struct needs_self_turns<Geometry, multi_polygon_tag>
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{
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static inline bool apply(Geometry const& multi)
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{
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typedef typename boost::range_value<Geometry>::type polygon_type;
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std::size_t const n = boost::size(multi);
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return n > 1 || (n == 1
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&& needs_self_turns<polygon_type>
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::apply(*boost::begin(multi)));
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}
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};
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}} // namespace detail::overlay
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#endif // DOXYGEN_NO_DETAIL
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}} // namespace boost::geometry
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#endif // BOOST_GEOMETRY_ALGORITHMS_DETAIL_OVERLAY_NEEDS_SELF_TURNS_HPP
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