Libosmium  2.18.0
Fast and flexible C++ library for working with OpenStreetMap data
wkb.hpp
Go to the documentation of this file.
1 #ifndef OSMIUM_GEOM_WKB_HPP
2 #define OSMIUM_GEOM_WKB_HPP
3 
4 /*
5 
6 This file is part of Osmium (https://osmcode.org/libosmium).
7 
8 Copyright 2013-2022 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 
37 #include <osmium/geom/factory.hpp>
38 #include <osmium/util/endian.hpp>
39 
40 #include <algorithm>
41 #include <cstddef>
42 #include <cstdint>
43 #include <string>
44 
45 namespace osmium {
46 
47  namespace geom {
48 
49  enum class wkb_type : bool {
50  wkb = false,
51  ewkb = true
52  }; // enum class wkb_type
53 
54  enum class out_type : bool {
55  binary = false,
56  hex = true
57  }; // enum class out_type
58 
59  namespace detail {
60 
61  template <typename T>
62  inline void str_push(std::string& str, T data) {
63  str.append(reinterpret_cast<const char*>(&data), sizeof(T));
64  }
65 
66  inline std::string convert_to_hex(const std::string& str) {
67  static const char* lookup_hex = "0123456789ABCDEF";
68  std::string out;
69  out.reserve(str.size() * 2);
70 
71  for (char c : str) {
72  out += lookup_hex[(static_cast<unsigned int>(c) >> 4U) & 0xfU];
73  out += lookup_hex[ static_cast<unsigned int>(c) & 0xfU];
74  }
75 
76  return out;
77  }
78 
79  class WKBFactoryImpl {
80 
88  enum wkbGeometryType : uint32_t {
89  wkbPoint = 1,
90  wkbLineString = 2,
91  wkbPolygon = 3,
92  wkbMultiPoint = 4,
93  wkbMultiLineString = 5,
94  wkbMultiPolygon = 6,
95  wkbGeometryCollection = 7,
96 
97  // SRID-presence flag (EWKB)
98  wkbSRID = 0x20000000
99  }; // enum wkbGeometryType
100 
104  enum class wkb_byte_order_type : uint8_t {
105  XDR = 0, // Big Endian
106  NDR = 1 // Little Endian
107  }; // enum class wkb_byte_order_type
108 
109  std::string m_data;
110  uint32_t m_points = 0;
111  int m_srid;
112  wkb_type m_wkb_type;
113  out_type m_out_type;
114 
115  std::size_t m_linestring_size_offset = 0;
116  std::size_t m_polygons = 0;
117  std::size_t m_rings = 0;
118  std::size_t m_multipolygon_size_offset = 0;
119  std::size_t m_polygon_size_offset = 0;
120  std::size_t m_ring_size_offset = 0;
121 
122  std::size_t header(std::string& str, wkbGeometryType type, bool add_length) const {
123 #if __BYTE_ORDER == __LITTLE_ENDIAN
124  str_push(str, wkb_byte_order_type::NDR);
125 #else
126  str_push(str, wkb_byte_order_type::XDR);
127 #endif
128  if (m_wkb_type == wkb_type::ewkb) {
129  str_push(str, type | wkbSRID);
130  str_push(str, m_srid);
131  } else {
132  str_push(str, type);
133  }
134  const std::size_t offset = str.size();
135  if (add_length) {
136  str_push(str, static_cast<uint32_t>(0));
137  }
138  return offset;
139  }
140 
141  void set_size(const std::size_t offset, const std::size_t size) {
142  if (size > std::numeric_limits<uint32_t>::max()) {
143  throw geometry_error{"Too many points in geometry"};
144  }
145  const auto s = static_cast<uint32_t>(size);
146  std::copy_n(reinterpret_cast<const char*>(&s), sizeof(uint32_t), &m_data[offset]);
147  }
148 
149  public:
150 
151  using point_type = std::string;
152  using linestring_type = std::string;
153  using polygon_type = std::string;
154  using multipolygon_type = std::string;
155  using ring_type = std::string;
156 
157  explicit WKBFactoryImpl(int srid, wkb_type wtype = wkb_type::wkb, out_type otype = out_type::binary) :
158  m_srid(srid),
159  m_wkb_type(wtype),
160  m_out_type(otype) {
161  }
162 
163  /* Point */
164 
165  point_type make_point(const osmium::geom::Coordinates& xy) const {
166  std::string data;
167  header(data, wkbPoint, false);
168  str_push(data, xy.x);
169  str_push(data, xy.y);
170 
171  if (m_out_type == out_type::hex) {
172  return convert_to_hex(data);
173  }
174 
175  return data;
176  }
177 
178  /* LineString */
179 
180  void linestring_start() {
181  m_data.clear();
182  m_linestring_size_offset = header(m_data, wkbLineString, true);
183  }
184 
185  void linestring_add_location(const osmium::geom::Coordinates& xy) {
186  str_push(m_data, xy.x);
187  str_push(m_data, xy.y);
188  }
189 
190  linestring_type linestring_finish(std::size_t num_points) {
191  set_size(m_linestring_size_offset, num_points);
192  std::string data;
193 
194  using std::swap;
195  swap(data, m_data);
196 
197  if (m_out_type == out_type::hex) {
198  return convert_to_hex(data);
199  }
200 
201  return data;
202  }
203 
204  /* Polygon */
205 
206  void polygon_start() {
207  m_data.clear();
208  set_size(header(m_data, wkbPolygon, true), 1);
209  m_ring_size_offset = m_data.size();
210  str_push(m_data, static_cast<uint32_t>(0));
211  }
212 
213  void polygon_add_location(const osmium::geom::Coordinates& xy) {
214  str_push(m_data, xy.x);
215  str_push(m_data, xy.y);
216  }
217 
218  polygon_type polygon_finish(std::size_t num_points) {
219  set_size(m_ring_size_offset, num_points);
220  std::string data;
221 
222  using std::swap;
223  swap(data, m_data);
224 
225  if (m_out_type == out_type::hex) {
226  return convert_to_hex(data);
227  }
228 
229  return data;
230  }
231 
232  /* MultiPolygon */
233 
234  void multipolygon_start() {
235  m_data.clear();
236  m_polygons = 0;
237  m_multipolygon_size_offset = header(m_data, wkbMultiPolygon, true);
238  }
239 
240  void multipolygon_polygon_start() {
241  ++m_polygons;
242  m_rings = 0;
243  m_polygon_size_offset = header(m_data, wkbPolygon, true);
244  }
245 
246  void multipolygon_polygon_finish() {
247  set_size(m_polygon_size_offset, m_rings);
248  }
249 
250  void multipolygon_outer_ring_start() {
251  ++m_rings;
252  m_points = 0;
253  m_ring_size_offset = m_data.size();
254  str_push(m_data, static_cast<uint32_t>(0));
255  }
256 
257  void multipolygon_outer_ring_finish() {
258  set_size(m_ring_size_offset, m_points);
259  }
260 
261  void multipolygon_inner_ring_start() {
262  ++m_rings;
263  m_points = 0;
264  m_ring_size_offset = m_data.size();
265  str_push(m_data, static_cast<uint32_t>(0));
266  }
267 
268  void multipolygon_inner_ring_finish() {
269  set_size(m_ring_size_offset, m_points);
270  }
271 
272  void multipolygon_add_location(const osmium::geom::Coordinates& xy) {
273  str_push(m_data, xy.x);
274  str_push(m_data, xy.y);
275  ++m_points;
276  }
277 
278  multipolygon_type multipolygon_finish() {
279  set_size(m_multipolygon_size_offset, m_polygons);
280  std::string data;
281 
282  using std::swap;
283  swap(data, m_data);
284 
285  if (m_out_type == out_type::hex) {
286  return convert_to_hex(data);
287  }
288 
289  return data;
290  }
291 
292  }; // class WKBFactoryImpl
293 
294  } // namespace detail
295 
296  template <typename TProjection = IdentityProjection>
298 
299  } // namespace geom
300 
301 } // namespace osmium
302 
303 #endif // OSMIUM_GEOM_WKB_HPP
Definition: factory.hpp:149
Definition: attr.hpp:342
wkb_type
Definition: wkb.hpp:49
out_type
Definition: wkb.hpp:54
type
Definition: entity_bits.hpp:63
Namespace for everything in the Osmium library.
Definition: assembler.hpp:53
Definition: coordinates.hpp:48
double y
Definition: coordinates.hpp:51
double x
Definition: coordinates.hpp:50