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>
applyboost::geometry::detail::num_segments::range_count48 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 {
applyboost::geometry::resolve_variant::num_segments151 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>
operator ()boost::geometry::resolve_variant::num_segments::visitor166 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
applyboost::geometry::resolve_variant::num_segments173 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>
num_segments(Geometry const & 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
205