├── .gitignore ├── .travis.yml ├── LICENSE ├── Makefile ├── README.md ├── contributors.txt ├── doc.go ├── twkb.go ├── twkb_test.go └── types.go /.gitignore: -------------------------------------------------------------------------------- 1 | # Compiled Object files, Static and Dynamic libs (Shared Objects) 2 | *.o 3 | *.a 4 | *.so 5 | 6 | # Folders 7 | _obj 8 | _test 9 | 10 | # Architecture specific extensions/prefixes 11 | *.[568vq] 12 | [568vq].out 13 | 14 | *.cgo1.go 15 | *.cgo2.c 16 | _cgo_defun.c 17 | _cgo_gotypes.go 18 | _cgo_export.* 19 | 20 | _testmain.go 21 | 22 | *.exe 23 | *.test 24 | *.prof 25 | -------------------------------------------------------------------------------- /.travis.yml: -------------------------------------------------------------------------------- 1 | language: go 2 | 3 | go: 4 | - 1.5 5 | - tip 6 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | Apache License 2 | Version 2.0, January 2004 3 | http://www.apache.org/licenses/ 4 | 5 | TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 6 | 7 | 1. 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We also recommend that a 185 | file or class name and description of purpose be included on the 186 | same "printed page" as the copyright notice for easier 187 | identification within third-party archives. 188 | 189 | Copyright {yyyy} {name of copyright owner} 190 | 191 | Licensed under the Apache License, Version 2.0 (the "License"); 192 | you may not use this file except in compliance with the License. 193 | You may obtain a copy of the License at 194 | 195 | http://www.apache.org/licenses/LICENSE-2.0 196 | 197 | Unless required by applicable law or agreed to in writing, software 198 | distributed under the License is distributed on an "AS IS" BASIS, 199 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 200 | See the License for the specific language governing permissions and 201 | limitations under the License. 202 | 203 | -------------------------------------------------------------------------------- /Makefile: -------------------------------------------------------------------------------- 1 | TAGS := "${GOOS} amd64" 2 | BENCHTIME := "1m" 3 | 4 | clean: 5 | go clean 6 | 7 | deps: 8 | go get github.com/stretchr/testify/assert 9 | 10 | build: 11 | go clean 12 | go build -tags ${TAGS} 13 | 14 | test: 15 | go test -v 16 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # TWKB Go Library 2 | 3 | [![Build Status](https://travis-ci.org/devork/twkb.png?branch=master)](https://travis-ci.org/devork/twkb) 4 | 5 | A small GO parser for the [TWKB specification](https://github.com/TWKB/Specification) 6 | 7 | # Usage 8 | 9 | `go get github.com/devork/twkb` 10 | 11 | ```go 12 | data, _ := hex.DecodeString("01000204") 13 | geom, err := Decode(bytes.NewReader(data)) 14 | 15 | if err != nil { 16 | t.Fatalf("Failed to decode point geometry: err = %s", err) 17 | } 18 | 19 | // Do something magical with the geometry returned 20 | ``` 21 | 22 | The library is usable, but could do with some optimisations. 23 | -------------------------------------------------------------------------------- /contributors.txt: -------------------------------------------------------------------------------- 1 | Alex Davies-Moore 2 | -------------------------------------------------------------------------------- /doc.go: -------------------------------------------------------------------------------- 1 | package twkb 2 | -------------------------------------------------------------------------------- /twkb.go: -------------------------------------------------------------------------------- 1 | /* 2 | Copyright [2015] Alex Davies-Moore 3 | 4 | Licensed under the Apache License, Version 2.0 (the "License"); 5 | you may not use this file except in compliance with the License. 6 | You may obtain a copy of the License at 7 | 8 | http://www.apache.org/licenses/LICENSE-2.0 9 | 10 | Unless required by applicable law or agreed to in writing, software 11 | distributed under the License is distributed on an "AS IS" BASIS, 12 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 | See the License for the specific language governing permissions and 14 | limitations under the License. 15 | */ 16 | 17 | package twkb 18 | 19 | import ( 20 | "encoding/binary" 21 | "errors" 22 | "io" 23 | "math" 24 | ) 25 | 26 | // BBox is represents the bounding box for the geom. The format is 27 | type BBox []float64 28 | 29 | // GeomType represents the specific geometry type 30 | type GeomType uint8 31 | 32 | // Standard geometry types 33 | const ( 34 | _ GeomType = iota 35 | POINT 36 | LINESTRING 37 | POLYGON 38 | MULTIPOINT 39 | MULTILINESTRING 40 | MULTIPOLYGON 41 | GEOMETRYCOLLECTION 42 | ) 43 | 44 | // Dimension types 45 | const ( 46 | XY uint8 = iota 47 | XYZ 48 | XYM 49 | XYZM 50 | ) 51 | 52 | // masks 53 | const ( 54 | bbox uint8 = 0x01 55 | size uint8 = 0x02 56 | idlist uint8 = 0x04 57 | exprec uint8 = 0x08 58 | empty uint8 = 0x10 59 | ) 60 | 61 | // Common errors 62 | var ( 63 | ErrUnknownGeom = errors.New("unknown geometry type") 64 | ) 65 | 66 | type decoder struct { 67 | r io.Reader 68 | refpoint [4]int64 69 | factors [4]int64 70 | ndims int 71 | bbox, size, idlist, empty bool 72 | length uint64 73 | } 74 | 75 | type mhdr struct { 76 | idlist []int64 77 | ngeoms int 78 | } 79 | 80 | func (d *decoder) read(v interface{}) error { 81 | return binary.Read(d.r, binary.BigEndian, v) 82 | } 83 | 84 | // Decode converts the given data into a Geometry type 85 | func Decode(r io.Reader) (Geometry, error) { 86 | var flag uint8 87 | var decoder = &decoder{r: r} 88 | 89 | err := decoder.read(&flag) 90 | 91 | if err != nil { 92 | return nil, err 93 | } 94 | 95 | hdr := Hdr{} 96 | 97 | // Geom type and precision header 98 | hdr.gtype = GeomType(flag & 0x0F) 99 | 100 | if hdr.gtype > GEOMETRYCOLLECTION || hdr.gtype < POINT { 101 | return nil, ErrUnknownGeom 102 | } 103 | 104 | precision := unzigzag(uint64(flag&0xF0)) >> 4 105 | decoder.factors[0] = int64(math.Pow10(int(precision))) 106 | decoder.factors[1] = decoder.factors[0] 107 | 108 | // Metadata 109 | err = decoder.read(&flag) 110 | 111 | if err != nil { 112 | return nil, err 113 | } 114 | 115 | decoder.bbox = (flag&bbox == bbox) 116 | decoder.size = (flag&size == size) 117 | decoder.idlist = (flag&idlist == idlist) 118 | decoder.empty = (flag&empty == empty) 119 | 120 | hdr.dim = XY 121 | decoder.ndims = 2 122 | 123 | // Z and/or M Dims 124 | if flag&exprec == exprec { 125 | var extended uint8 126 | 127 | err := decoder.read(&extended) 128 | 129 | if err != nil { 130 | return nil, err 131 | } 132 | 133 | switch { 134 | case extended&XYZM == XYZM: 135 | hdr.dim = XYZM 136 | decoder.ndims = 4 137 | zprec := int((extended & 0x1C) >> 2) 138 | mprec := int((extended & 0xE0) >> 5) 139 | decoder.factors[2] = int64(math.Pow10(zprec)) 140 | decoder.factors[3] = int64(math.Pow10(mprec)) 141 | 142 | case extended&XYZ == XYZ: 143 | hdr.dim = XYZ 144 | decoder.ndims = 3 145 | zprec := int((extended & 0x1C) >> 2) 146 | decoder.factors[2] = int64(math.Pow10(zprec)) 147 | 148 | case extended&XYM == XYM: 149 | hdr.dim = XYM 150 | decoder.ndims = 3 151 | mprec := int((extended & 0xE0) >> 5) 152 | decoder.factors[2] = int64(math.Pow10(mprec)) 153 | 154 | } 155 | } 156 | 157 | if decoder.size { 158 | decoder.length, err = readVarInt64(decoder) 159 | 160 | if err != nil { 161 | return nil, err 162 | } 163 | } 164 | 165 | if decoder.bbox { 166 | var bbox = make(BBox, decoder.ndims*2) 167 | var min, max int64 168 | 169 | for idx := 0; idx < decoder.ndims; idx++ { 170 | min, err = readVarSInt64(decoder) 171 | 172 | if err != nil { 173 | return nil, err 174 | } 175 | 176 | max, err = readVarSInt64(decoder) 177 | 178 | if err != nil { 179 | return nil, err 180 | } 181 | 182 | bbox[idx] = float64(min) 183 | bbox[idx+decoder.ndims] = float64(min + max) 184 | } 185 | 186 | hdr.bbox = bbox 187 | 188 | } 189 | 190 | switch hdr.gtype { 191 | case POINT: 192 | return decodePoint(decoder, &hdr) 193 | case LINESTRING: 194 | return decodeLineString(decoder, &hdr) 195 | case POLYGON: 196 | return decodePolygon(decoder, &hdr) 197 | case MULTIPOINT: 198 | return decodeMultiPoint(decoder, &hdr) 199 | case MULTILINESTRING: 200 | return decodeMultiLineString(decoder, &hdr) 201 | case MULTIPOLYGON: 202 | return decodeMultiPolygon(decoder, &hdr) 203 | case GEOMETRYCOLLECTION: 204 | return decodeCollection(decoder, &hdr) 205 | } 206 | 207 | return &hdr, nil 208 | } 209 | 210 | func decodePoint(d *decoder, h *Hdr) (*Point, error) { 211 | coords, bbox, err := readCoords(d, 1) 212 | 213 | if err != nil { 214 | return nil, err 215 | } 216 | 217 | if h != nil { 218 | 219 | if bbox != nil { 220 | h.bbox = bbox 221 | } 222 | return &Point{h, coords[0]}, nil 223 | } 224 | 225 | return &Point{nil, coords[0]}, nil 226 | } 227 | 228 | func decodeLineString(d *decoder, h *Hdr) (*LineString, error) { 229 | size, err := readVarInt64(d) 230 | 231 | if err != nil { 232 | return nil, err 233 | } 234 | 235 | coords, bbox, err := readCoords(d, int(size)) 236 | 237 | if err != nil { 238 | return nil, err 239 | } 240 | 241 | if h != nil { 242 | if bbox != nil { 243 | h.bbox = bbox 244 | } 245 | 246 | return &LineString{h, coords}, nil 247 | } 248 | 249 | return &LineString{nil, coords}, nil 250 | } 251 | 252 | func decodePolygon(d *decoder, h *Hdr) (*Polygon, error) { 253 | size, err := readVarInt64(d) 254 | 255 | if err != nil { 256 | return nil, err 257 | } 258 | 259 | var ringSize uint64 260 | rings := make([]LinearRing, size) 261 | for ring := 0; ring < int(size); ring++ { 262 | ringSize, err = readVarInt64(d) 263 | 264 | if err != nil { 265 | return nil, err 266 | } 267 | 268 | rings[ring], _, err = readCoords(d, int(ringSize)) 269 | } 270 | 271 | if h != nil { 272 | return &Polygon{h, rings}, nil 273 | } 274 | 275 | return &Polygon{nil, rings}, nil 276 | } 277 | 278 | func decodeMultiPoint(d *decoder, h *Hdr) (*MultiPoint, error) { 279 | var err error 280 | m, err := readMHdr(d) 281 | 282 | if err != nil { 283 | return nil, err 284 | } 285 | 286 | var points = make([]Point, m.ngeoms) 287 | var p *Point 288 | for idx := 0; idx < m.ngeoms; idx++ { 289 | p, err = decodePoint(d, nil) 290 | 291 | if err != nil { 292 | return nil, err 293 | } 294 | 295 | points[idx] = *p 296 | } 297 | 298 | return &MultiPoint{h, m.idlist, points}, nil 299 | } 300 | 301 | func decodeMultiLineString(d *decoder, h *Hdr) (*MultiLineString, error) { 302 | var err error 303 | m, err := readMHdr(d) 304 | 305 | if err != nil { 306 | return nil, err 307 | } 308 | 309 | var lines = make([]LineString, m.ngeoms) 310 | var p *LineString 311 | for idx := 0; idx < m.ngeoms; idx++ { 312 | p, err = decodeLineString(d, nil) 313 | 314 | if err != nil { 315 | return nil, err 316 | } 317 | 318 | lines[idx] = *p 319 | } 320 | 321 | return &MultiLineString{h, m.idlist, lines}, nil 322 | } 323 | 324 | func decodeMultiPolygon(d *decoder, h *Hdr) (*MultiPolygon, error) { 325 | var err error 326 | m, err := readMHdr(d) 327 | 328 | if err != nil { 329 | return nil, err 330 | } 331 | 332 | var polys = make([]Polygon, m.ngeoms) 333 | var p *Polygon 334 | for idx := 0; idx < m.ngeoms; idx++ { 335 | p, err = decodePolygon(d, nil) 336 | 337 | if err != nil { 338 | return nil, err 339 | } 340 | 341 | polys[idx] = *p 342 | } 343 | 344 | return &MultiPolygon{h, m.idlist, polys}, nil 345 | } 346 | 347 | func decodeCollection(d *decoder, h *Hdr) (*GeometryCollection, error) { 348 | var err error 349 | m, err := readMHdr(d) 350 | 351 | if err != nil { 352 | return nil, err 353 | } 354 | 355 | var geoms = make([]Geometry, m.ngeoms) 356 | var g Geometry 357 | 358 | for idx := 0; idx < m.ngeoms; idx++ { 359 | g, err = Decode(d.r) 360 | 361 | if err != nil { 362 | return nil, err 363 | } 364 | 365 | geoms[idx] = g 366 | } 367 | 368 | return &GeometryCollection{h, m.idlist, geoms}, nil 369 | } 370 | 371 | func readCoords(d *decoder, size int) ([]Coordinate, BBox, error) { 372 | var coords = make([]Coordinate, size) 373 | var coord Coordinate 374 | var val int64 375 | var err error 376 | var bbox BBox 377 | 378 | if !d.bbox { 379 | bbox = make(BBox, d.ndims*2) 380 | for idx := 0; idx < d.ndims; idx++ { 381 | bbox[idx] = math.MaxInt64 382 | bbox[idx+d.ndims] = math.MinInt64 383 | } 384 | } 385 | for i := 0; i < size; i++ { 386 | coord = make(Coordinate, d.ndims) 387 | for j := 0; j < d.ndims; j++ { 388 | val, err = readVarSInt64(d) 389 | 390 | if err != nil { 391 | return nil, nil, err 392 | } 393 | 394 | d.refpoint[j] += val 395 | coord[j] = float64(d.refpoint[j]) / float64(d.factors[j]) 396 | 397 | if bbox != nil { 398 | if coord[j] < bbox[j] { 399 | bbox[j] = coord[j] 400 | } 401 | 402 | if coord[j] > bbox[j+d.ndims] { 403 | bbox[j+d.ndims] = coord[j] 404 | } 405 | } 406 | } 407 | coords[i] = coord 408 | 409 | } 410 | 411 | return coords, bbox, nil 412 | } 413 | 414 | func unzigzag(nVal uint64) int64 { 415 | if (nVal & 1) == 0 { 416 | return int64(nVal >> 1) 417 | } 418 | return int64(-(nVal >> 1) - 1) 419 | } 420 | 421 | func readVarInt64(d *decoder) (uint64, error) { 422 | var byte uint8 423 | var val uint64 424 | var shift uint 425 | var err error 426 | for { 427 | err = d.read(&byte) 428 | 429 | if err != nil { 430 | return 0, err 431 | } 432 | 433 | if byte&0x80 == 0 { 434 | return val | (uint64(byte) << shift), nil 435 | } 436 | 437 | val = val | (uint64(byte)&0x7f)<