1 | // Boost.Geometry (aka GGL, Generic Geometry Library) |
2 | |
3 | // Copyright (c) 2007-2012 Barend Gehrels, Amsterdam, the Netherlands. |
4 | // Copyright (c) 2008-2012 Bruno Lalande, Paris, France. |
5 | // Copyright (c) 2009-2012 Mateusz Loskot, London, UK. |
6 | |
7 | // Parts of Boost.Geometry are redesigned from Geodan's Geographic Library |
8 | // (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands. |
9 | |
10 | // Use, modification and distribution is subject to the Boost Software License, |
11 | // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at |
12 | // http://www.boost.org/LICENSE_1_0.txt) |
13 | |
14 | #ifndef BOOST_GEOMETRY_ALGORITHMS_CLEAR_HPP |
15 | #define BOOST_GEOMETRY_ALGORITHMS_CLEAR_HPP |
16 | |
17 | |
18 | #include <boost/type_traits/remove_const.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/algorithms/not_implemented.hpp> |
25 | #include <boost/geometry/core/access.hpp> |
26 | #include <boost/geometry/core/exterior_ring.hpp> |
27 | #include <boost/geometry/core/interior_rings.hpp> |
28 | #include <boost/geometry/core/mutable_range.hpp> |
29 | #include <boost/geometry/core/tag_cast.hpp> |
30 | #include <boost/geometry/core/tags.hpp> |
31 | #include <boost/geometry/geometries/concepts/check.hpp> |
32 | |
33 | |
34 | namespace boost { namespace geometry |
35 | { |
36 | |
37 | #ifndef DOXYGEN_NO_DETAIL |
38 | namespace detail { namespace clear |
39 | { |
40 | |
41 | template <typename Geometry> |
42 | struct collection_clear |
43 | { |
44 | static inline void apply(Geometry& geometry) |
45 | { |
46 | traits::clear<Geometry>::apply(geometry); |
47 | } |
48 | }; |
49 | |
50 | template <typename Polygon> |
51 | struct polygon_clear |
52 | { |
53 | static inline void apply(Polygon& polygon) |
54 | { |
55 | traits::clear |
56 | < |
57 | typename boost::remove_reference |
58 | < |
59 | typename traits::interior_mutable_type<Polygon>::type |
60 | >::type |
61 | >::apply(interior_rings(polygon)); |
62 | traits::clear |
63 | < |
64 | typename boost::remove_reference |
65 | < |
66 | typename traits::ring_mutable_type<Polygon>::type |
67 | >::type |
68 | >::apply(exterior_ring(polygon)); |
69 | } |
70 | }; |
71 | |
72 | template <typename Geometry> |
73 | struct no_action |
74 | { |
75 | static inline void apply(Geometry& ) |
76 | { |
77 | } |
78 | }; |
79 | |
80 | |
81 | }} // namespace detail::clear |
82 | #endif // DOXYGEN_NO_DETAIL |
83 | |
84 | #ifndef DOXYGEN_NO_DISPATCH |
85 | namespace dispatch |
86 | { |
87 | |
88 | template |
89 | < |
90 | typename Geometry, |
91 | typename Tag = typename tag_cast<typename tag<Geometry>::type, multi_tag>::type |
92 | > |
93 | struct clear: not_implemented<Tag> |
94 | {}; |
95 | |
96 | // Point/box/segment do not have clear. So specialize to do nothing. |
97 | template <typename Geometry> |
98 | struct clear<Geometry, point_tag> |
99 | : detail::clear::no_action<Geometry> |
100 | {}; |
101 | |
102 | template <typename Geometry> |
103 | struct clear<Geometry, box_tag> |
104 | : detail::clear::no_action<Geometry> |
105 | {}; |
106 | |
107 | template <typename Geometry> |
108 | struct clear<Geometry, segment_tag> |
109 | : detail::clear::no_action<Geometry> |
110 | {}; |
111 | |
112 | template <typename Geometry> |
113 | struct clear<Geometry, linestring_tag> |
114 | : detail::clear::collection_clear<Geometry> |
115 | {}; |
116 | |
117 | template <typename Geometry> |
118 | struct clear<Geometry, ring_tag> |
119 | : detail::clear::collection_clear<Geometry> |
120 | {}; |
121 | |
122 | |
123 | // Polygon can (indirectly) use std for clear |
124 | template <typename Polygon> |
125 | struct clear<Polygon, polygon_tag> |
126 | : detail::clear::polygon_clear<Polygon> |
127 | {}; |
128 | |
129 | |
130 | template <typename Geometry> |
131 | struct clear<Geometry, multi_tag> |
132 | : detail::clear::collection_clear<Geometry> |
133 | {}; |
134 | |
135 | |
136 | } // namespace dispatch |
137 | #endif // DOXYGEN_NO_DISPATCH |
138 | |
139 | |
140 | namespace resolve_variant { |
141 | |
142 | template <typename Geometry> |
143 | struct clear |
144 | { |
145 | static inline void apply(Geometry& geometry) |
146 | { |
147 | dispatch::clear<Geometry>::apply(geometry); |
148 | } |
149 | }; |
150 | |
151 | template <BOOST_VARIANT_ENUM_PARAMS(typename T)> |
152 | struct clear<variant<BOOST_VARIANT_ENUM_PARAMS(T)> > |
153 | { |
154 | struct visitor: static_visitor<void> |
155 | { |
156 | template <typename Geometry> |
157 | inline void operator()(Geometry& geometry) const |
158 | { |
159 | clear<Geometry>::apply(geometry); |
160 | } |
161 | }; |
162 | |
163 | static inline void apply(variant<BOOST_VARIANT_ENUM_PARAMS(T)>& geometry) |
164 | { |
165 | boost::apply_visitor(visitor(), geometry); |
166 | } |
167 | }; |
168 | |
169 | } // namespace resolve_variant |
170 | |
171 | |
172 | /*! |
173 | \brief Clears a linestring, ring or polygon (exterior+interiors) or multi* |
174 | \details Generic function to clear a geometry. All points will be removed from the collection or collections |
175 | making up the geometry. In most cases this is equivalent to the .clear() method of a std::vector<...>. In |
176 | the case of a polygon, this clear functionality is automatically called for the exterior ring, and for the |
177 | interior ring collection. In the case of a point, boxes and segments, nothing will happen. |
178 | \ingroup clear |
179 | \tparam Geometry \tparam_geometry |
180 | \param geometry \param_geometry which will be cleared |
181 | \note points and boxes cannot be cleared, instead they can be set to zero by "assign_zero" |
182 | |
183 | \qbk{[include reference/algorithms/clear.qbk]} |
184 | */ |
185 | template <typename Geometry> |
186 | inline void clear(Geometry& geometry) |
187 | { |
188 | concept::check<Geometry>(); |
189 | |
190 | resolve_variant::clear<Geometry>::apply(geometry); |
191 | } |
192 | |
193 | |
194 | }} // namespace boost::geometry |
195 | |
196 | |
197 | #endif // BOOST_GEOMETRY_ALGORITHMS_CLEAR_HPP |
198 | |