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1 | // Boost.Geometry (aka GGL, Generic Geometry Library) |
2 | ||
3 | // Copyright (c) 2014, Oracle and/or its affiliates. | |
4 | ||
5 | // Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle | |
6 | ||
7 | // Licensed under the Boost Software License version 1.0. | |
8 | // http://www.boost.org/users/license.html | |
9 | ||
10 | #ifndef BOOST_GEOMETRY_ALGORITHMS_NUM_SEGMENTS_HPP | |
11 | #define BOOST_GEOMETRY_ALGORITHMS_NUM_SEGMENTS_HPP | |
12 | ||
13 | #include <cstddef> | |
14 | ||
15 | #include <boost/mpl/size_t.hpp> | |
16 | #include <boost/mpl/times.hpp> | |
17 | ||
18 | #include <boost/range.hpp> | |
19 | ||
20 | #include <boost/variant/apply_visitor.hpp> | |
21 | #include <boost/variant/static_visitor.hpp> | |
22 | #include <boost/variant/variant_fwd.hpp> | |
23 | ||
24 | #include <boost/geometry/core/closure.hpp> | |
25 | #include <boost/geometry/core/tag.hpp> | |
26 | #include <boost/geometry/core/tags.hpp> | |
27 | ||
28 | #include <boost/geometry/util/range.hpp> | |
29 | ||
30 | #include <boost/geometry/geometries/concepts/check.hpp> | |
31 | ||
32 | #include <boost/geometry/algorithms/not_implemented.hpp> | |
33 | ||
34 | #include <boost/geometry/algorithms/detail/counting.hpp> | |
35 | ||
36 | ||
37 | namespace boost { namespace geometry | |
38 | { | |
39 | ||
40 | #ifndef DOXYGEN_NO_DETAIL | |
41 | namespace detail { namespace num_segments | |
42 | { | |
43 | ||
44 | ||
45 | struct range_count | |
46 | { | |
47 | template <typename Range> | |
48 | static inline std::size_t apply(Range const& range) | |
49 | { | |
50 | std::size_t n = boost::size(range); | |
51 | if ( n <= 1 ) | |
52 | { | |
53 | return 0; | |
54 | } | |
55 | ||
56 | return | |
57 | geometry::closure<Range>::value == open | |
58 | ? | |
59 | n | |
60 | : | |
61 | static_cast<std::size_t>(n - 1); | |
62 | } | |
63 | }; | |
64 | ||
65 | }} // namespace detail::num_segments | |
66 | #endif // DOXYGEN_NO_DETAIL | |
67 | ||
68 | ||
69 | ||
70 | #ifndef DOXYGEN_NO_DISPATCH | |
71 | namespace dispatch | |
72 | { | |
73 | ||
74 | template <typename Geometry, typename Tag = typename tag<Geometry>::type> | |
75 | struct num_segments | |
76 | : not_implemented<Tag> | |
77 | {}; | |
78 | ||
79 | template <typename Geometry> | |
80 | struct num_segments<Geometry, point_tag> | |
81 | : detail::counting::other_count<0> | |
82 | {}; | |
83 | ||
84 | // the number of segments (1-dimensional faces) of the hypercube is | |
85 | // given by the formula: d * 2^(d-1), where d is the dimension of the | |
86 | // hypercube; see also: | |
87 | // http://en.wikipedia.org/wiki/Hypercube | |
88 | template <typename Geometry> | |
89 | struct num_segments<Geometry, box_tag> | |
90 | : detail::counting::other_count | |
91 | < | |
92 | geometry::dimension<Geometry>::value | |
93 | * (1 << (geometry::dimension<Geometry>::value - 1)) | |
94 | > | |
95 | {}; | |
96 | ||
97 | template <typename Geometry> | |
98 | struct num_segments<Geometry, segment_tag> | |
99 | : detail::counting::other_count<1> | |
100 | {}; | |
101 | ||
102 | template <typename Geometry> | |
103 | struct num_segments<Geometry, linestring_tag> | |
104 | : detail::num_segments::range_count | |
105 | {}; | |
106 | ||
107 | template <typename Geometry> | |
108 | struct num_segments<Geometry, ring_tag> | |
109 | : detail::num_segments::range_count | |
110 | {}; | |
111 | ||
112 | template <typename Geometry> | |
113 | struct num_segments<Geometry, polygon_tag> | |
114 | : detail::counting::polygon_count<detail::num_segments::range_count> | |
115 | {}; | |
116 | ||
117 | template <typename Geometry> | |
118 | struct num_segments<Geometry, multi_point_tag> | |
119 | : detail::counting::other_count<0> | |
120 | {}; | |
121 | ||
122 | template <typename Geometry> | |
123 | struct num_segments<Geometry, multi_linestring_tag> | |
124 | : detail::counting::multi_count | |
125 | < | |
126 | num_segments< typename boost::range_value<Geometry>::type> | |
127 | > | |
128 | {}; | |
129 | ||
130 | template <typename Geometry> | |
131 | struct num_segments<Geometry, multi_polygon_tag> | |
132 | : detail::counting::multi_count | |
133 | < | |
134 | num_segments< typename boost::range_value<Geometry>::type> | |
135 | > | |
136 | {}; | |
137 | ||
138 | ||
139 | } // namespace dispatch | |
140 | #endif // DOXYGEN_NO_DISPATCH | |
141 | ||
142 | ||
143 | ||
144 | namespace resolve_variant | |
145 | { | |
146 | ||
147 | ||
148 | template <typename Geometry> | |
149 | struct num_segments | |
150 | { | |
151 | static inline std::size_t apply(Geometry const& geometry) | |
152 | { | |
153 | concepts::check<Geometry const>(); | |
154 | ||
155 | return dispatch::num_segments<Geometry>::apply(geometry); | |
156 | } | |
157 | }; | |
158 | ||
159 | ||
160 | template <BOOST_VARIANT_ENUM_PARAMS(typename T)> | |
161 | struct num_segments<boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)> > | |
162 | { | |
163 | struct visitor: boost::static_visitor<std::size_t> | |
164 | { | |
165 | template <typename Geometry> | |
166 | inline std::size_t operator()(Geometry const& geometry) const | |
167 | { | |
168 | return num_segments<Geometry>::apply(geometry); | |
169 | } | |
170 | }; | |
171 | ||
172 | static inline std::size_t | |
173 | apply(boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)> const& geometry) | |
174 | { | |
175 | return boost::apply_visitor(visitor(), geometry); | |
176 | } | |
177 | }; | |
178 | ||
179 | ||
180 | } // namespace resolve_variant | |
181 | ||
182 | ||
183 | ||
184 | /*! | |
185 | \brief \brief_calc{number of segments} | |
186 | \ingroup num_segments | |
187 | \details \details_calc{num_segments, number of segments}. | |
188 | \tparam Geometry \tparam_geometry | |
189 | \param geometry \param_geometry | |
190 | \return \return_calc{number of segments} | |
191 | ||
192 | \qbk{[include reference/algorithms/num_segments.qbk]} | |
193 | */ | |
194 | template <typename Geometry> | |
195 | inline std::size_t num_segments(Geometry const& geometry) | |
196 | { | |
197 | return resolve_variant::num_segments<Geometry>::apply(geometry); | |
198 | } | |
199 | ||
200 | ||
201 | ||
202 | }} // namespace boost::geometry | |
203 | ||
204 | #endif // BOOST_GEOMETRY_ALGORITHMS_NUM_SEGMENTS_HPP |