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1 | // Boost.Geometry (aka GGL, Generic Geometry Library) |
2 | ||
3 | // Copyright (c) 2014-2015, Oracle and/or its affiliates. | |
4 | ||
5 | // Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle | |
6 | // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle | |
7 | ||
8 | // Licensed under the Boost Software License version 1.0. | |
9 | // http://www.boost.org/users/license.html | |
10 | ||
11 | #ifndef BOOST_GEOMETRY_ALGORITHMS_DETAIL_IS_VALID_LINEAR_HPP | |
12 | #define BOOST_GEOMETRY_ALGORITHMS_DETAIL_IS_VALID_LINEAR_HPP | |
13 | ||
14 | #include <cstddef> | |
15 | ||
16 | #include <boost/range.hpp> | |
17 | ||
18 | #include <boost/geometry/core/closure.hpp> | |
19 | #include <boost/geometry/core/point_type.hpp> | |
20 | #include <boost/geometry/core/tags.hpp> | |
21 | ||
22 | #include <boost/geometry/util/condition.hpp> | |
23 | #include <boost/geometry/util/range.hpp> | |
24 | ||
25 | #include <boost/geometry/algorithms/equals.hpp> | |
26 | #include <boost/geometry/algorithms/validity_failure_type.hpp> | |
27 | #include <boost/geometry/algorithms/detail/check_iterator_range.hpp> | |
28 | #include <boost/geometry/algorithms/detail/is_valid/has_invalid_coordinate.hpp> | |
29 | #include <boost/geometry/algorithms/detail/is_valid/has_spikes.hpp> | |
30 | #include <boost/geometry/algorithms/detail/num_distinct_consecutive_points.hpp> | |
31 | ||
32 | #include <boost/geometry/algorithms/dispatch/is_valid.hpp> | |
33 | ||
34 | ||
35 | namespace boost { namespace geometry | |
36 | { | |
37 | ||
38 | #ifndef DOXYGEN_NO_DETAIL | |
39 | namespace detail { namespace is_valid | |
40 | { | |
41 | ||
42 | ||
43 | template <typename Linestring> | |
44 | struct is_valid_linestring | |
45 | { | |
46 | template <typename VisitPolicy> | |
47 | static inline bool apply(Linestring const& linestring, | |
48 | VisitPolicy& visitor) | |
49 | { | |
50 | if (has_invalid_coordinate<Linestring>::apply(linestring, visitor)) | |
51 | { | |
52 | return false; | |
53 | } | |
54 | ||
55 | if (boost::size(linestring) < 2) | |
56 | { | |
57 | return visitor.template apply<failure_few_points>(); | |
58 | } | |
59 | ||
60 | std::size_t num_distinct = detail::num_distinct_consecutive_points | |
61 | < | |
62 | Linestring, | |
63 | 3u, | |
64 | true, | |
65 | not_equal_to<typename point_type<Linestring>::type> | |
66 | >::apply(linestring); | |
67 | ||
68 | if (num_distinct < 2u) | |
69 | { | |
70 | return | |
71 | visitor.template apply<failure_wrong_topological_dimension>(); | |
72 | } | |
73 | ||
74 | if (num_distinct == 2u) | |
75 | { | |
76 | return visitor.template apply<no_failure>(); | |
77 | } | |
78 | return ! has_spikes<Linestring, closed>::apply(linestring, visitor); | |
79 | } | |
80 | }; | |
81 | ||
82 | ||
83 | }} // namespace detail::is_valid | |
84 | #endif // DOXYGEN_NO_DETAIL | |
85 | ||
86 | ||
87 | ||
88 | ||
89 | #ifndef DOXYGEN_NO_DISPATCH | |
90 | namespace dispatch | |
91 | { | |
92 | ||
93 | ||
94 | // A linestring is a curve. | |
95 | // A curve is 1-dimensional so it has to have at least two distinct | |
96 | // points. | |
97 | // A curve is simple if it does not pass through the same point twice, | |
98 | // with the possible exception of its two endpoints | |
99 | // | |
100 | // There is an option here as to whether spikes are allowed for linestrings; | |
101 | // here we pass this as an additional template parameter: allow_spikes | |
102 | // If allow_spikes is set to true, spikes are allowed, false otherwise. | |
103 | // By default, spikes are disallowed | |
104 | // | |
105 | // Reference: OGC 06-103r4 (6.1.6.1) | |
106 | template <typename Linestring, bool AllowEmptyMultiGeometries> | |
107 | struct is_valid | |
108 | < | |
109 | Linestring, linestring_tag, AllowEmptyMultiGeometries | |
110 | > : detail::is_valid::is_valid_linestring<Linestring> | |
111 | {}; | |
112 | ||
113 | ||
114 | // A MultiLinestring is a MultiCurve | |
115 | // A MultiCurve is simple if all of its elements are simple and the | |
116 | // only intersections between any two elements occur at Points that | |
117 | // are on the boundaries of both elements. | |
118 | // | |
119 | // Reference: OGC 06-103r4 (6.1.8.1; Fig. 9) | |
120 | template <typename MultiLinestring, bool AllowEmptyMultiGeometries> | |
121 | class is_valid | |
122 | < | |
123 | MultiLinestring, multi_linestring_tag, AllowEmptyMultiGeometries | |
124 | > | |
125 | { | |
126 | private: | |
127 | template <typename VisitPolicy> | |
128 | struct per_linestring | |
129 | { | |
130 | per_linestring(VisitPolicy& policy) : m_policy(policy) {} | |
131 | ||
132 | template <typename Linestring> | |
133 | inline bool apply(Linestring const& linestring) const | |
134 | { | |
135 | return detail::is_valid::is_valid_linestring | |
136 | < | |
137 | Linestring | |
138 | >::apply(linestring, m_policy); | |
139 | } | |
140 | ||
141 | VisitPolicy& m_policy; | |
142 | }; | |
143 | ||
144 | public: | |
145 | template <typename VisitPolicy> | |
146 | static inline bool apply(MultiLinestring const& multilinestring, | |
147 | VisitPolicy& visitor) | |
148 | { | |
149 | if (BOOST_GEOMETRY_CONDITION( | |
150 | AllowEmptyMultiGeometries && boost::empty(multilinestring))) | |
151 | { | |
152 | return visitor.template apply<no_failure>(); | |
153 | } | |
154 | ||
155 | return detail::check_iterator_range | |
156 | < | |
157 | per_linestring<VisitPolicy>, | |
158 | false // do not check for empty multilinestring (done above) | |
159 | >::apply(boost::begin(multilinestring), | |
160 | boost::end(multilinestring), | |
161 | per_linestring<VisitPolicy>(visitor)); | |
162 | } | |
163 | }; | |
164 | ||
165 | ||
166 | } // namespace dispatch | |
167 | #endif // DOXYGEN_NO_DISPATCH | |
168 | ||
169 | ||
170 | }} // namespace boost::geometry | |
171 | ||
172 | ||
173 | #endif // BOOST_GEOMETRY_ALGORITHMS_DETAIL_IS_VALID_LINEAR_HPP |