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1 | // Boost.Geometry (aka GGL, Generic Geometry Library) |
2 | ||
1e59de90 | 3 | // Copyright (c) 2014-2021, Oracle and/or its affiliates. |
7c673cae | 4 | |
1e59de90 | 5 | // Contributed and/or modified by Vissarion Fysikopoulos, on behalf of Oracle |
7c673cae FG |
6 | // Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle |
7 | // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle | |
8 | ||
9 | // Licensed under the Boost Software License version 1.0. | |
10 | // http://www.boost.org/users/license.html | |
11 | ||
12 | #ifndef BOOST_GEOMETRY_ALGORITHMS_DETAIL_IS_VALID_LINEAR_HPP | |
13 | #define BOOST_GEOMETRY_ALGORITHMS_DETAIL_IS_VALID_LINEAR_HPP | |
14 | ||
15 | #include <cstddef> | |
16 | ||
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17 | #include <boost/range/begin.hpp> |
18 | #include <boost/range/empty.hpp> | |
19 | #include <boost/range/end.hpp> | |
20 | #include <boost/range/size.hpp> | |
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21 | |
22 | #include <boost/geometry/algorithms/equals.hpp> | |
23 | #include <boost/geometry/algorithms/validity_failure_type.hpp> | |
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24 | #include <boost/geometry/algorithms/detail/is_valid/has_invalid_coordinate.hpp> |
25 | #include <boost/geometry/algorithms/detail/is_valid/has_spikes.hpp> | |
26 | #include <boost/geometry/algorithms/detail/num_distinct_consecutive_points.hpp> | |
27 | ||
28 | #include <boost/geometry/algorithms/dispatch/is_valid.hpp> | |
29 | ||
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30 | #include <boost/geometry/core/closure.hpp> |
31 | #include <boost/geometry/core/point_type.hpp> | |
32 | #include <boost/geometry/core/tags.hpp> | |
33 | ||
34 | #include <boost/geometry/util/condition.hpp> | |
35 | ||
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36 | |
37 | namespace boost { namespace geometry | |
38 | { | |
39 | ||
40 | #ifndef DOXYGEN_NO_DETAIL | |
41 | namespace detail { namespace is_valid | |
42 | { | |
43 | ||
44 | ||
45 | template <typename Linestring> | |
46 | struct is_valid_linestring | |
47 | { | |
b32b8144 | 48 | template <typename VisitPolicy, typename Strategy> |
7c673cae | 49 | static inline bool apply(Linestring const& linestring, |
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50 | VisitPolicy& visitor, |
51 | Strategy const& strategy) | |
7c673cae | 52 | { |
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53 | // TODO: Consider checking coordinates based on coordinate system |
54 | // Right now they are only checked for infinity in all systems. | |
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55 | if (has_invalid_coordinate<Linestring>::apply(linestring, visitor)) |
56 | { | |
57 | return false; | |
58 | } | |
59 | ||
60 | if (boost::size(linestring) < 2) | |
61 | { | |
62 | return visitor.template apply<failure_few_points>(); | |
63 | } | |
64 | ||
65 | std::size_t num_distinct = detail::num_distinct_consecutive_points | |
66 | < | |
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67 | Linestring, 3u, true |
68 | >::apply(linestring, strategy); | |
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69 | |
70 | if (num_distinct < 2u) | |
71 | { | |
72 | return | |
73 | visitor.template apply<failure_wrong_topological_dimension>(); | |
74 | } | |
75 | ||
76 | if (num_distinct == 2u) | |
77 | { | |
78 | return visitor.template apply<no_failure>(); | |
79 | } | |
b32b8144 | 80 | |
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81 | // TODO: This algorithm iterates over the linestring until a spike is |
82 | // found and only then the decision about the validity is made. This | |
83 | // is done regardless of VisitPolicy. | |
84 | // An obvious improvement is to avoid calling the algorithm at all if | |
85 | // spikes are allowed which is the default. | |
1e59de90 | 86 | return ! has_spikes<Linestring>::apply(linestring, visitor, strategy); |
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87 | } |
88 | }; | |
89 | ||
90 | ||
91 | }} // namespace detail::is_valid | |
92 | #endif // DOXYGEN_NO_DETAIL | |
93 | ||
94 | ||
95 | ||
96 | ||
97 | #ifndef DOXYGEN_NO_DISPATCH | |
98 | namespace dispatch | |
99 | { | |
100 | ||
101 | ||
102 | // A linestring is a curve. | |
103 | // A curve is 1-dimensional so it has to have at least two distinct | |
104 | // points. | |
105 | // A curve is simple if it does not pass through the same point twice, | |
106 | // with the possible exception of its two endpoints | |
107 | // | |
108 | // There is an option here as to whether spikes are allowed for linestrings; | |
109 | // here we pass this as an additional template parameter: allow_spikes | |
110 | // If allow_spikes is set to true, spikes are allowed, false otherwise. | |
111 | // By default, spikes are disallowed | |
112 | // | |
113 | // Reference: OGC 06-103r4 (6.1.6.1) | |
114 | template <typename Linestring, bool AllowEmptyMultiGeometries> | |
115 | struct is_valid | |
116 | < | |
117 | Linestring, linestring_tag, AllowEmptyMultiGeometries | |
118 | > : detail::is_valid::is_valid_linestring<Linestring> | |
119 | {}; | |
120 | ||
121 | ||
122 | // A MultiLinestring is a MultiCurve | |
123 | // A MultiCurve is simple if all of its elements are simple and the | |
124 | // only intersections between any two elements occur at Points that | |
125 | // are on the boundaries of both elements. | |
126 | // | |
127 | // Reference: OGC 06-103r4 (6.1.8.1; Fig. 9) | |
128 | template <typename MultiLinestring, bool AllowEmptyMultiGeometries> | |
129 | class is_valid | |
130 | < | |
131 | MultiLinestring, multi_linestring_tag, AllowEmptyMultiGeometries | |
132 | > | |
133 | { | |
b32b8144 | 134 | template <typename VisitPolicy, typename Strategy> |
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135 | struct per_linestring |
136 | { | |
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137 | per_linestring(VisitPolicy& policy, Strategy const& strategy) |
138 | : m_policy(policy) | |
139 | , m_strategy(strategy) | |
140 | {} | |
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141 | |
142 | template <typename Linestring> | |
1e59de90 | 143 | inline bool operator()(Linestring const& linestring) const |
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144 | { |
145 | return detail::is_valid::is_valid_linestring | |
146 | < | |
147 | Linestring | |
b32b8144 | 148 | >::apply(linestring, m_policy, m_strategy); |
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149 | } |
150 | ||
151 | VisitPolicy& m_policy; | |
b32b8144 | 152 | Strategy const& m_strategy; |
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153 | }; |
154 | ||
155 | public: | |
b32b8144 | 156 | template <typename VisitPolicy, typename Strategy> |
7c673cae | 157 | static inline bool apply(MultiLinestring const& multilinestring, |
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158 | VisitPolicy& visitor, |
159 | Strategy const& strategy) | |
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160 | { |
161 | if (BOOST_GEOMETRY_CONDITION( | |
162 | AllowEmptyMultiGeometries && boost::empty(multilinestring))) | |
163 | { | |
164 | return visitor.template apply<no_failure>(); | |
165 | } | |
166 | ||
1e59de90 | 167 | using per_ls = per_linestring<VisitPolicy, Strategy>; |
b32b8144 | 168 | |
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169 | return std::all_of(boost::begin(multilinestring), |
170 | boost::end(multilinestring), | |
171 | per_ls(visitor, strategy)); | |
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172 | } |
173 | }; | |
174 | ||
175 | ||
176 | } // namespace dispatch | |
177 | #endif // DOXYGEN_NO_DISPATCH | |
178 | ||
179 | ||
180 | }} // namespace boost::geometry | |
181 | ||
182 | ||
183 | #endif // BOOST_GEOMETRY_ALGORITHMS_DETAIL_IS_VALID_LINEAR_HPP |