187 lines
5.6 KiB
C++
187 lines
5.6 KiB
C++
// Boost.Geometry (aka GGL, Generic Geometry Library)
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// Copyright (c) 2023 Adam Wulkiewicz, Lodz, Poland.
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// Copyright (c) 2014-2021, Oracle and/or its affiliates.
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// Contributed and/or modified by Vissarion Fysikopoulos, on behalf of Oracle
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// Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle
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// Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
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// Licensed under the Boost Software License version 1.0.
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// http://www.boost.org/users/license.html
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#ifndef BOOST_GEOMETRY_ALGORITHMS_DETAIL_IS_VALID_LINEAR_HPP
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#define BOOST_GEOMETRY_ALGORITHMS_DETAIL_IS_VALID_LINEAR_HPP
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#include <cstddef>
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#include <boost/range/begin.hpp>
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#include <boost/range/empty.hpp>
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#include <boost/range/end.hpp>
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#include <boost/range/size.hpp>
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#include <boost/geometry/algorithms/equals.hpp>
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#include <boost/geometry/algorithms/validity_failure_type.hpp>
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#include <boost/geometry/algorithms/detail/is_valid/has_invalid_coordinate.hpp>
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#include <boost/geometry/algorithms/detail/is_valid/has_spikes.hpp>
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#include <boost/geometry/algorithms/detail/num_distinct_consecutive_points.hpp>
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#include <boost/geometry/algorithms/dispatch/is_valid.hpp>
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#include <boost/geometry/core/closure.hpp>
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#include <boost/geometry/core/point_type.hpp>
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#include <boost/geometry/core/tags.hpp>
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#include <boost/geometry/util/constexpr.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 is_valid
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{
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template <typename Linestring>
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struct is_valid_linestring
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{
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template <typename VisitPolicy, typename Strategy>
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static inline bool apply(Linestring const& linestring,
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VisitPolicy& visitor,
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Strategy const& strategy)
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{
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// TODO: Consider checking coordinates based on coordinate system
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// Right now they are only checked for infinity in all systems.
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if (has_invalid_coordinate<Linestring>::apply(linestring, visitor))
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{
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return false;
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}
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if (boost::size(linestring) < 2)
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{
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return visitor.template apply<failure_few_points>();
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}
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std::size_t num_distinct = detail::num_distinct_consecutive_points
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<
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Linestring, 3u, true
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>::apply(linestring, strategy);
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if (num_distinct < 2u)
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{
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return
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visitor.template apply<failure_wrong_topological_dimension>();
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}
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if (num_distinct == 2u)
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{
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return visitor.template apply<no_failure>();
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}
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// TODO: This algorithm iterates over the linestring until a spike is
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// found and only then the decision about the validity is made. This
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// is done regardless of VisitPolicy.
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// An obvious improvement is to avoid calling the algorithm at all if
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// spikes are allowed which is the default.
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return ! has_spikes<Linestring>::apply(linestring, visitor, strategy);
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}
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};
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}} // namespace detail::is_valid
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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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// A linestring is a curve.
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// A curve is 1-dimensional so it has to have at least two distinct
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// points.
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// A curve is simple if it does not pass through the same point twice,
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// with the possible exception of its two endpoints
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//
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// There is an option here as to whether spikes are allowed for linestrings;
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// here we pass this as an additional template parameter: allow_spikes
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// If allow_spikes is set to true, spikes are allowed, false otherwise.
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// By default, spikes are disallowed
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//
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// Reference: OGC 06-103r4 (6.1.6.1)
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template <typename Linestring, bool AllowEmptyMultiGeometries>
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struct is_valid
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<
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Linestring, linestring_tag, AllowEmptyMultiGeometries
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> : detail::is_valid::is_valid_linestring<Linestring>
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{};
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// A MultiLinestring is a MultiCurve
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// A MultiCurve is simple if all of its elements are simple and the
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// only intersections between any two elements occur at Points that
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// are on the boundaries of both elements.
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//
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// Reference: OGC 06-103r4 (6.1.8.1; Fig. 9)
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template <typename MultiLinestring, bool AllowEmptyMultiGeometries>
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class is_valid
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<
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MultiLinestring, multi_linestring_tag, AllowEmptyMultiGeometries
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>
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{
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template <typename VisitPolicy, typename Strategy>
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struct per_linestring
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{
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per_linestring(VisitPolicy& policy, Strategy const& strategy)
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: m_policy(policy)
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, m_strategy(strategy)
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{}
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template <typename Linestring>
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inline bool operator()(Linestring const& linestring) const
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{
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return detail::is_valid::is_valid_linestring
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<
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Linestring
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>::apply(linestring, m_policy, m_strategy);
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}
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VisitPolicy& m_policy;
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Strategy const& m_strategy;
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};
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public:
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template <typename VisitPolicy, typename Strategy>
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static inline bool apply(MultiLinestring const& multilinestring,
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VisitPolicy& visitor,
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Strategy const& strategy)
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{
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if BOOST_GEOMETRY_CONSTEXPR (AllowEmptyMultiGeometries)
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{
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if (boost::empty(multilinestring))
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{
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return visitor.template apply<no_failure>();
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}
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}
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using per_ls = per_linestring<VisitPolicy, Strategy>;
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return std::all_of(boost::begin(multilinestring),
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boost::end(multilinestring),
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per_ls(visitor, strategy));
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}
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};
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} // namespace dispatch
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#endif // DOXYGEN_NO_DISPATCH
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}} // namespace boost::geometry
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#endif // BOOST_GEOMETRY_ALGORITHMS_DETAIL_IS_VALID_LINEAR_HPP
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