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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_DETAIL_CLOSEST_FEATURE_RANGE_TO_RANGE_HPP | |
11 | #define BOOST_GEOMETRY_ALGORITHMS_DETAIL_CLOSEST_FEATURE_RANGE_TO_RANGE_HPP | |
12 | ||
13 | #include <cstddef> | |
14 | ||
15 | #include <iterator> | |
16 | #include <utility> | |
17 | ||
18 | #include <boost/geometry/core/assert.hpp> | |
19 | #include <boost/geometry/core/point_type.hpp> | |
20 | #include <boost/geometry/strategies/distance.hpp> | |
21 | #include <boost/geometry/algorithms/dispatch/distance.hpp> | |
22 | #include <boost/geometry/index/rtree.hpp> | |
23 | ||
24 | ||
25 | namespace boost { namespace geometry | |
26 | { | |
27 | ||
28 | #ifndef DOXYGEN_NO_DETAIL | |
29 | namespace detail { namespace closest_feature | |
30 | { | |
31 | ||
32 | ||
33 | // returns a pair of a objects where the first is an object of the | |
34 | // r-tree range and the second an object of the query range that | |
35 | // realizes the closest feature of the two ranges | |
36 | class range_to_range_rtree | |
37 | { | |
38 | private: | |
39 | template | |
40 | < | |
41 | typename RTreeRangeIterator, | |
42 | typename QueryRangeIterator, | |
43 | typename Strategy, | |
44 | typename RTreeValueType, | |
45 | typename Distance | |
46 | > | |
47 | static inline void apply(RTreeRangeIterator rtree_first, | |
48 | RTreeRangeIterator rtree_last, | |
49 | QueryRangeIterator queries_first, | |
50 | QueryRangeIterator queries_last, | |
51 | Strategy const& strategy, | |
52 | RTreeValueType& rtree_min, | |
53 | QueryRangeIterator& qit_min, | |
54 | Distance& dist_min) | |
55 | { | |
56 | typedef index::rtree<RTreeValueType, index::linear<8> > rtree_type; | |
57 | ||
58 | BOOST_GEOMETRY_ASSERT( rtree_first != rtree_last ); | |
59 | BOOST_GEOMETRY_ASSERT( queries_first != queries_last ); | |
60 | ||
61 | Distance const zero = Distance(0); | |
62 | dist_min = zero; | |
63 | ||
64 | // create -- packing algorithm | |
65 | rtree_type rt(rtree_first, rtree_last); | |
66 | ||
67 | RTreeValueType t_v; | |
68 | bool first = true; | |
69 | ||
70 | for (QueryRangeIterator qit = queries_first; | |
71 | qit != queries_last; ++qit, first = false) | |
72 | { | |
73 | std::size_t n = rt.query(index::nearest(*qit, 1), &t_v); | |
74 | ||
75 | BOOST_GEOMETRY_ASSERT( n > 0 ); | |
76 | // n above is unused outside BOOST_GEOMETRY_ASSERT, | |
77 | // hence the call to boost::ignore_unused below | |
78 | // | |
79 | // however, t_v (initialized by the call to rt.query(...)) | |
80 | // is used below, which is why we cannot put the call to | |
81 | // rt.query(...) inside BOOST_GEOMETRY_ASSERT | |
82 | boost::ignore_unused(n); | |
83 | ||
84 | Distance dist = dispatch::distance | |
85 | < | |
86 | RTreeValueType, | |
87 | typename std::iterator_traits | |
88 | < | |
89 | QueryRangeIterator | |
90 | >::value_type, | |
91 | Strategy | |
92 | >::apply(t_v, *qit, strategy); | |
93 | ||
94 | if (first || dist < dist_min) | |
95 | { | |
96 | dist_min = dist; | |
97 | rtree_min = t_v; | |
98 | qit_min = qit; | |
99 | if ( math::equals(dist_min, zero) ) | |
100 | { | |
101 | return; | |
102 | } | |
103 | } | |
104 | } | |
105 | } | |
106 | ||
107 | public: | |
108 | template <typename RTreeRangeIterator, typename QueryRangeIterator> | |
109 | struct return_type | |
110 | { | |
111 | typedef std::pair | |
112 | < | |
113 | typename std::iterator_traits<RTreeRangeIterator>::value_type, | |
114 | QueryRangeIterator | |
115 | > type; | |
116 | }; | |
117 | ||
118 | ||
119 | template | |
120 | < | |
121 | typename RTreeRangeIterator, | |
122 | typename QueryRangeIterator, | |
123 | typename Strategy, | |
124 | typename Distance | |
125 | > | |
126 | static inline typename return_type | |
127 | < | |
128 | RTreeRangeIterator, QueryRangeIterator | |
129 | >::type apply(RTreeRangeIterator rtree_first, | |
130 | RTreeRangeIterator rtree_last, | |
131 | QueryRangeIterator queries_first, | |
132 | QueryRangeIterator queries_last, | |
133 | Strategy const& strategy, | |
134 | Distance& dist_min) | |
135 | { | |
136 | typedef typename std::iterator_traits | |
137 | < | |
138 | RTreeRangeIterator | |
139 | >::value_type rtree_value_type; | |
140 | ||
141 | rtree_value_type rtree_min; | |
142 | QueryRangeIterator qit_min; | |
143 | ||
144 | apply(rtree_first, rtree_last, queries_first, queries_last, | |
145 | strategy, rtree_min, qit_min, dist_min); | |
146 | ||
147 | return std::make_pair(rtree_min, qit_min); | |
148 | } | |
149 | ||
150 | ||
151 | template | |
152 | < | |
153 | typename RTreeRangeIterator, | |
154 | typename QueryRangeIterator, | |
155 | typename Strategy | |
156 | > | |
157 | static inline typename return_type | |
158 | < | |
159 | RTreeRangeIterator, QueryRangeIterator | |
160 | >::type apply(RTreeRangeIterator rtree_first, | |
161 | RTreeRangeIterator rtree_last, | |
162 | QueryRangeIterator queries_first, | |
163 | QueryRangeIterator queries_last, | |
164 | Strategy const& strategy) | |
165 | { | |
166 | typedef typename std::iterator_traits | |
167 | < | |
168 | RTreeRangeIterator | |
169 | >::value_type rtree_value_type; | |
170 | ||
171 | typename strategy::distance::services::return_type | |
172 | < | |
173 | Strategy, | |
174 | typename point_type<rtree_value_type>::type, | |
175 | typename point_type | |
176 | < | |
177 | typename std::iterator_traits | |
178 | < | |
179 | QueryRangeIterator | |
180 | >::value_type | |
181 | >::type | |
182 | >::type dist_min; | |
183 | ||
184 | return apply(rtree_first, rtree_last, queries_first, queries_last, | |
185 | strategy, dist_min); | |
186 | } | |
187 | }; | |
188 | ||
189 | ||
190 | }} // namespace detail::closest_feature | |
191 | #endif // DOXYGEN_NO_DETAIL | |
192 | ||
193 | }} // namespace boost::geometry | |
194 | ||
195 | ||
196 | #endif // BOOST_GEOMETRY_ALGORITHMS_DETAIL_CLOSEST_FEATURE_RANGE_TO_RANGE_HPP |