1 #ifndef OSMIUM_GEOM_GEOJSON_HPP
2 #define OSMIUM_GEOM_GEOJSON_HPP
3 
4 /*
5 
6 This file is part of Osmium (https://osmcode.org/libosmium).
7 
8 Copyright 2013-2021 Jochen Topf <jochen@topf.org> and others (see README).
9 
10 Boost Software License - Version 1.0 - August 17th, 2003
11 
12 Permission is hereby granted, free of charge, to any person or organization
13 obtaining a copy of the software and accompanying documentation covered by
14 this license (the "Software") to use, reproduce, display, distribute,
15 execute, and transmit the Software, and to prepare derivative works of the
16 Software, and to permit third-parties to whom the Software is furnished to
17 do so, all subject to the following:
18 
19 The copyright notices in the Software and this entire statement, including
20 the above license grant, this restriction and the following disclaimer,
21 must be included in all copies of the Software, in whole or in part, and
22 all derivative works of the Software, unless such copies or derivative
23 works are solely in the form of machine-executable object code generated by
24 a source language processor.
25 
26 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
27 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
28 FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
29 SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
30 FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
31 ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
32 DEALINGS IN THE SOFTWARE.
33 
34 */
35 
36 #include <osmium/geom/coordinates.hpp>
37 #include <osmium/geom/factory.hpp>
38 
39 #include <cassert>
40 #include <cstddef>
41 #include <string>
42 #include <utility>
43 
44 namespace osmium {
45 
46     namespace geom {
47 
48         namespace detail {
49 
50             class GeoJSONFactoryImpl {
51 
52                 std::string m_str;
53                 int m_precision;
54 
55             public:
56 
57                 using point_type        = std::string;
58                 using linestring_type   = std::string;
59                 using polygon_type      = std::string;
60                 using multipolygon_type = std::string;
61                 using ring_type         = std::string;
62 
GeoJSONFactoryImpl(int,int precision=7)63                 explicit GeoJSONFactoryImpl(int /*srid*/, int precision = 7) :
64                     m_precision(precision) {
65                 }
66 
67                 /* Point */
68 
69                 // { "type": "Point", "coordinates": [100.0, 0.0] }
make_point(const osmium::geom::Coordinates & xy) const70                 point_type make_point(const osmium::geom::Coordinates& xy) const {
71                     std::string str{"{\"type\":\"Point\",\"coordinates\":"};
72                     xy.append_to_string(str, '[', ',', ']', m_precision);
73                     str += "}";
74                     return str;
75                 }
76 
77                 /* LineString */
78 
79                 // { "type": "LineString", "coordinates": [ [100.0, 0.0], [101.0, 1.0] ] }
linestring_start()80                 void linestring_start() {
81                     m_str = "{\"type\":\"LineString\",\"coordinates\":[";
82                 }
83 
linestring_add_location(const osmium::geom::Coordinates & xy)84                 void linestring_add_location(const osmium::geom::Coordinates& xy) {
85                     xy.append_to_string(m_str, '[', ',', ']', m_precision);
86                     m_str += ',';
87                 }
88 
linestring_finish(size_t)89                 linestring_type linestring_finish(size_t /*num_points*/) {
90                     assert(!m_str.empty());
91                     std::string str;
92 
93                     using std::swap;
94                     swap(str, m_str);
95 
96                     str.back() = ']';
97                     str += "}";
98                     return str;
99                 }
100 
101                 /* Polygon */
polygon_start()102                 void polygon_start() {
103                     m_str = "{\"type\":\"Polygon\",\"coordinates\":[[";
104                 }
105 
polygon_add_location(const osmium::geom::Coordinates & xy)106                 void polygon_add_location(const osmium::geom::Coordinates& xy) {
107                     xy.append_to_string(m_str, '[', ',', ']', m_precision);
108                     m_str += ',';
109                 }
110 
polygon_finish(size_t)111                 polygon_type polygon_finish(size_t /*num_points*/) {
112                     assert(!m_str.empty());
113                     std::string str;
114 
115                     using std::swap;
116                     swap(str, m_str);
117 
118                     str.back() = ']';
119                     str += "]}";
120                     return str;
121                 }
122 
123                 /* MultiPolygon */
124 
multipolygon_start()125                 void multipolygon_start() {
126                     m_str = "{\"type\":\"MultiPolygon\",\"coordinates\":[";
127                 }
128 
multipolygon_polygon_start()129                 void multipolygon_polygon_start() {
130                     m_str += '[';
131                 }
132 
multipolygon_polygon_finish()133                 void multipolygon_polygon_finish() {
134                     m_str += "],";
135                 }
136 
multipolygon_outer_ring_start()137                 void multipolygon_outer_ring_start() {
138                     m_str += '[';
139                 }
140 
multipolygon_outer_ring_finish()141                 void multipolygon_outer_ring_finish() {
142                     assert(!m_str.empty());
143                     m_str.back() = ']';
144                 }
145 
multipolygon_inner_ring_start()146                 void multipolygon_inner_ring_start() {
147                     m_str += ",[";
148                 }
149 
multipolygon_inner_ring_finish()150                 void multipolygon_inner_ring_finish() {
151                     assert(!m_str.empty());
152                     m_str.back() = ']';
153                 }
154 
multipolygon_add_location(const osmium::geom::Coordinates & xy)155                 void multipolygon_add_location(const osmium::geom::Coordinates& xy) {
156                     xy.append_to_string(m_str, '[', ',', ']', m_precision);
157                     m_str += ',';
158                 }
159 
multipolygon_finish()160                 multipolygon_type multipolygon_finish() {
161                     assert(!m_str.empty());
162                     std::string str;
163 
164                     using std::swap;
165                     swap(str, m_str);
166 
167                     str.back() = ']';
168                     str += "}";
169                     return str;
170                 }
171 
172             }; // class GeoJSONFactoryImpl
173 
174         } // namespace detail
175 
176         template <typename TProjection = IdentityProjection>
177         using GeoJSONFactory = GeometryFactory<osmium::geom::detail::GeoJSONFactoryImpl, TProjection>;
178 
179     } // namespace geom
180 
181 } // namespace osmium
182 
183 #endif // OSMIUM_GEOM_GEOJSON_HPP
184