1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542
//! Reader module, contains the definitions of the types that a user should use to read a file //! //! //! The [Reader](struct.Reader.html) is the struct that actually reads the file from any source as long as it implements the //! `Read` Trait (`std::fs::File`, and `std::io::Cursor` for example). //! //! It is recommended to create a `Reader` using its //! [from_path](struct.Reader.html#method.from_path) method as this constructor //! will take care of opening the .shx and .dbf files corresponding to the .shp (if they exists). //! //! If you want to read a shapefile that is not storred in a file (e.g the shp data is in a buffer), //! you will have to construct the `Reader` "by hand" with its [new](struct.Reader.html#method.new) method. //! //! If you want the "manually" constructed `Reader` to also read the *shx* and *dbf* file content //! you will have to use [add_index_source](struct.Reader.html#method.add_index_source) and/or //! [add_dbf_source](struct.Reader.html#method.add_dbf_source) //! //! //! # Examples //! //! When reading from a file: //! //! Creates a reader from a path, then iterate over its `Shapes`, reading one shape each iteration //! ``` //! let reader = shapefile::Reader::from_path("tests/data/pointm.shp").unwrap(); //! for shape in reader { //! let shape = shape.unwrap(); //! println!("{}", shape); //! } //! ``` //! //! Creates a reader from a path, reads the whole file at once //! ``` //! let reader = shapefile::Reader::from_path("tests/data/pointm.shp").unwrap(); //! let shapes = reader.read().unwrap(); //! ``` //! //! If you know beforehand the exact type that the .shp file is made of, //! you can use the different `*_as::<S>()` functions.: //! - [read_as](struct.Reader.html#method.read_as) To read all the shapes as the specified type //! - [iter_shapes_as](struct.Reader.html#method.iter_shapes_as) To iterate over the shapes as shapes //! of the specified type //! - [iter_shapes_and_records_as](struct.Reader.html#method.iter_shapes_and_records_as) To iterate //! over both the shapes and records //! //! Otherwise use the functions that return [Shape](../record/enum.Shape.html)s and do a `match` //! //! - [read](struct.Reader.html#method.read) //! - [iter_shapes](struct.Reader.html#method.iter_shapes) //! - [iter_shapes_and_records](struct.Reader.html#method.iter_shapes_and_records) //! //! //! Two functions ([read](fn.read.html) and [read_as](fn.read_as.html)) are provided to read //! files with one function call (thus not having to build a `Reader`) use std::fs::File; use std::io::{BufReader, Read, Seek, SeekFrom}; use std::iter::FusedIterator; use std::path::Path; use byteorder::{BigEndian, ReadBytesExt}; use header; use record; use {Error, Shape}; use record::ReadableShape; const INDEX_RECORD_SIZE: usize = 2 * std::mem::size_of::<i32>(); pub(crate) struct ShapeIndex { pub offset: i32, pub record_size: i32, } /// Read the content of a .shx file fn read_index_file<T: Read>(mut source: T) -> Result<Vec<ShapeIndex>, Error> { let header = header::Header::read_from(&mut source)?; let num_shapes = ((header.file_length * 2) - header::HEADER_SIZE) / INDEX_RECORD_SIZE as i32; let mut shapes_index = Vec::<ShapeIndex>::with_capacity(num_shapes as usize); for _ in 0..num_shapes { let offset = source.read_i32::<BigEndian>()?; let record_size = source.read_i32::<BigEndian>()?; shapes_index.push(ShapeIndex { offset, record_size, }); } Ok(shapes_index) } /// Reads and returns one shape and its header from the source fn read_one_shape_as<T: Read, S: ReadableShape>( mut source: &mut T, ) -> Result<(record::RecordHeader, S), Error> { let hdr = record::RecordHeader::read_from(&mut source)?; let record_size = hdr.record_size * 2; let shape = S::read_from(&mut source, record_size)?; Ok((hdr, shape)) } /// Struct that handle iteration over the shapes of a .shp file pub struct ShapeIterator<T: Read, S: ReadableShape> { _shape: std::marker::PhantomData<S>, source: T, current_pos: usize, file_length: usize, } impl<T: Read, S: ReadableShape> Iterator for ShapeIterator<T, S> { type Item = Result<S, Error>; fn next(&mut self) -> Option<Self::Item> { if self.current_pos >= self.file_length { None } else { let (hdr, shape) = match read_one_shape_as::<T, S>(&mut self.source) { Err(e) => return Some(Err(e)), Ok(hdr_and_shape) => hdr_and_shape, }; self.current_pos += record::RecordHeader::SIZE; self.current_pos += hdr.record_size as usize * 2; Some(Ok(shape)) } } } impl<T: Read, S: ReadableShape> FusedIterator for ShapeIterator<T, S> {} pub struct ShapeRecordIterator<T: Read, S: ReadableShape> { shape_iter: ShapeIterator<T, S>, dbf_reader: dbase::Reader<T>, } impl<T: Read, S: ReadableShape> Iterator for ShapeRecordIterator<T, S> { type Item = Result<(S, dbase::Record), Error>; fn next(&mut self) -> Option<Self::Item> { let shape = match self.shape_iter.next()? { Err(e) => return Some(Err(e)), Ok(shp) => shp, }; let record = match self.dbf_reader.next()? { Err(e) => return Some(Err(Error::DbaseError(e))), Ok(rcd) => rcd, }; Some(Ok((shape, record))) } } impl<T: Read, S: ReadableShape> FusedIterator for ShapeRecordIterator<T, S> {} //TODO Make it possible for the dbf source to be of a different dtype ? /// struct that reads the content of a shapefile pub struct Reader<T: Read> { source: T, header: header::Header, shapes_index: Option<Vec<ShapeIndex>>, dbf_reader: Option<dbase::Reader<T>>, } impl<T: Read> Reader<T> { /// Creates a new Reader from a source that implements the `Read` trait /// /// The Shapefile header is read upon creation (but no reading of the Shapes is done) /// /// # Errors /// /// Will forward any `std::io::Error` /// /// Will also return an error if the data is not a shapefile (Wrong file code) /// /// Will also return an error if the shapetype read from the input source is invalid /// /// # Example /// /// ``` /// use std::fs::File; /// let file = File::open("tests/data/line.shp").unwrap(); /// let reader = shapefile::Reader::new(file).unwrap(); /// ``` pub fn new(mut source: T) -> Result<Reader<T>, Error> { let header = header::Header::read_from(&mut source)?; Ok(Reader { source, header, shapes_index: None, dbf_reader: None, }) } /// Returns a non-mutable reference to the header read /// /// # Examples /// /// ``` /// let reader = shapefile::Reader::from_path("tests/data/pointz.shp").unwrap(); /// let header = reader.header(); /// assert_eq!(header.shape_type, shapefile::ShapeType::PointZ); /// ``` pub fn header(&self) -> &header::Header { &self.header } /// Reads all the shape as shape of a certain type. /// /// To be used if you know in advance which shape type the file contains. /// /// # Errors /// The function has an additional error that is returned if the shape type you asked to be /// read does not match the actual shape type in the file. /// /// # Examples /// /// ``` /// use shapefile::Reader; /// let mut reader = Reader::from_path("tests/data/linem.shp").unwrap(); /// let polylines_m = reader.read_as::<shapefile::PolylineM>().unwrap(); // we ask for the correct type /// ``` /// /// ``` /// use shapefile::Reader; /// let mut reader = Reader::from_path("tests/data/linem.shp").unwrap(); /// let polylines = reader.read_as::<shapefile::Polyline>(); // we ask for the wrong type /// assert_eq!(polylines.is_err(), true); /// ``` pub fn read_as<S: ReadableShape>(self) -> Result<Vec<S>, Error> { self.iter_shapes_as::<S>().collect() } /// Reads all the shapes and returns them /// /// # Examples /// ``` /// use shapefile::Reader; /// let mut reader = Reader::from_path("tests/data/multipoint.shp").unwrap(); /// let shapes = reader.read().unwrap(); /// for shape in shapes { /// match shape { /// shapefile::Shape::Multipoint(pts) => println!(" Yay Multipoints: {}", pts), /// _ => panic!("ups, not multipoints"), /// } /// } /// ``` /// pub fn read(self) -> Result<Vec<Shape>, Error> { self.into_iter().collect() } /// Read and return _only_ the records contained in the *.dbf* file pub fn read_records(self) -> Result<Vec<dbase::Record>, Error> { let dbf_reader = self.dbf_reader.ok_or(Error::MissingDbf)?; dbf_reader.read().or_else(|e| Err(Error::DbaseError(e))) } /// Returns an iterator that tries to read the shapes as the specified type /// Will return an error of the type `S` does not match the actual type in the file /// /// # Examples /// /// ``` /// let reader = shapefile::Reader::from_path("tests/data/multipoint.shp").unwrap(); /// for multipoints in reader.iter_shapes_as::<shapefile::Multipoint>() { /// let points = multipoints.unwrap(); /// println!("{}", points); /// } /// ``` pub fn iter_shapes_as<S: ReadableShape>(self) -> ShapeIterator<T, S> { ShapeIterator { _shape: std::marker::PhantomData, source: self.source, current_pos: header::HEADER_SIZE as usize, file_length: (self.header.file_length * 2) as usize, } } /// Returns an iterator that to reads the shapes wraps them in the enum [Shape](enum.Shape.html) /// You do not need to call this method and can iterate over the `Reader` directly /// /// # Examples /// /// ``` /// let reader = shapefile::Reader::from_path("tests/data/multipoint.shp").unwrap(); /// for shape in reader.iter_shapes() { /// match shape.unwrap() { /// shapefile::Shape::Multipatch(shp) => println!("Multipoint!"), /// _ => println!("Other type of shape"), /// } /// } /// ``` /// /// ``` /// let reader = shapefile::Reader::from_path("tests/data/multipoint.shp").unwrap(); /// for shape in reader { /// match shape.unwrap() { /// shapefile::Shape::Multipatch(shp) => println!("Multipoint!"), /// _ => println!("Other type of shape"), /// } /// } /// ``` pub fn iter_shapes(self) -> ShapeIterator<T, Shape> { ShapeIterator { _shape: std::marker::PhantomData, source: self.source, current_pos: header::HEADER_SIZE as usize, file_length: (self.header.file_length * 2) as usize, } } /// Returns an iterator over the Shapes and their Records /// /// # Errors /// /// The `Result` will be an error if the .dbf wasn't found /// /// # Example /// ``` /// use shapefile::{Reader, Multipatch}; /// let reader = Reader::from_path("tests/data/multipatch.shp").unwrap(); /// for result in reader.iter_shapes_and_records_as::<Multipatch>().unwrap() { /// let (shape, record) = result.unwrap(); /// // ... /// } /// ``` pub fn iter_shapes_and_records_as<S: ReadableShape>( mut self, ) -> Result<ShapeRecordIterator<T, S>, Error> { let maybe_dbf_reader = self.dbf_reader.take(); if let Some(dbf_reader) = maybe_dbf_reader { let shape_iter = self.iter_shapes_as::<S>(); Ok(ShapeRecordIterator { shape_iter, dbf_reader, }) } else { Err(Error::MissingDbf) } } /// Returns an iterator over the Shapes and their Records /// /// # Errors /// /// The `Result` will be an error if the .dbf wasn't found /// /// # Example /// ``` /// use shapefile::{Reader, Shape}; /// let reader = Reader::from_path("tests/data/multipatch.shp").unwrap(); /// for result in reader.iter_shapes_and_records().unwrap() { /// let (shape, record) = result.unwrap(); /// match shape { /// Shape::Multipatch(multip) => {/*...*/ }, /// //.. /// _ => { /*...*/ } /// } /// // ... /// } /// ``` pub fn iter_shapes_and_records(self) -> Result<ShapeRecordIterator<T, Shape>, Error> { self.iter_shapes_and_records_as::<Shape>() } /// Reads the index file from the source /// This allows to later read shapes by giving their index without reading the whole file /// /// (see [read_nth_shape()](struct.Reader.html#method.read_nth_shape)) pub fn add_index_source(&mut self, source: T) -> Result<(), Error> { self.shapes_index = Some(read_index_file(source)?); Ok(()) } /// Adds the `source` as the source where the dbf record will be read from pub fn add_dbf_source(&mut self, source: T) -> Result<(), Error> { let dbf_reader = dbase::Reader::new(source)?; self.dbf_reader = Some(dbf_reader); Ok(()) } } impl<T: Read> IntoIterator for Reader<T> { type Item = Result<Shape, Error>; type IntoIter = ShapeIterator<T, Shape>; fn into_iter(self) -> Self::IntoIter { self.iter_shapes() } } impl Reader<BufReader<File>> { /// Creates a reader from a path to a file /// /// Will attempt to read both the .shx and .dbf associated with the file, /// if they do not exists the function will not fail, and you will get an error later /// if you try to use a function that requires the file to be present. /// /// /// # Examples /// /// ``` /// use std::path::Path; /// assert_eq!(Path::new("tests/data/linem.dbf").exists(), false); /// assert_eq!(Path::new("tests/data/linem.shx").exists(), false); /// /// // both .shx and .dbf does not exists, but creation does not fail /// let mut reader = shapefile::Reader::from_path("tests/data/linem.shp").unwrap(); /// let result = reader.iter_shapes_and_records(); /// assert_eq!(result.is_err(), true); /// /// /// assert_eq!(Path::new("tests/data/multipatch.dbf").exists(), true); /// /// let mut reader = shapefile::Reader::from_path("tests/data/multipatch.shp").unwrap(); /// let result = reader.iter_shapes_and_records(); /// assert_eq!(result.is_err(), false); /// ``` /// /// /// ``` /// use shapefile::Reader; /// let mut reader = Reader::from_path("tests/data/line.shp").unwrap(); /// let polylines = reader.read_as::<shapefile::Polyline>().unwrap(); /// ``` pub fn from_path<P: AsRef<Path>>(path: P) -> Result<Self, Error> { let shape_path = path.as_ref().to_path_buf(); let shx_path = shape_path.with_extension("shx"); let dbf_path = shape_path.with_extension("dbf"); let source = BufReader::new(File::open(shape_path)?); let mut reader = Self::new(source)?; if shx_path.exists() { let index_source = BufReader::new(File::open(shx_path)?); reader.add_index_source(index_source)?; } if dbf_path.exists() { let dbf_source = BufReader::new(File::open(dbf_path)?); reader.add_dbf_source(dbf_source)?; } Ok(reader) } } /// Sources that implements `Seek` have access to /// a few more methods that uses the *index file(.shx)* impl<T: Read + Seek> Reader<T> { /// Reads the `n`th shape of the shapefile /// /// # Returns /// /// `None` if the index is out of range /// /// # Errors /// /// This method will return an `Error::MissingIndexFile` if you use it /// but no *.shx* was found when opening the shapefile. /// /// pub fn read_nth_shape_as<S: ReadableShape>( &mut self, index: usize, ) -> Option<Result<S, Error>> { if let Some(ref shapes_index) = self.shapes_index { let offset = { let shape_idx = shapes_index.get(index)?; (shape_idx.offset * 2) as u64 }; if let Err(e) = self.source.seek(SeekFrom::Start(offset)) { return Some(Err(Error::IoError(e))); } let (_, shape) = match read_one_shape_as::<T, S>(&mut self.source) { Err(e) => return Some(Err(e)), Ok(hdr_and_shape) => hdr_and_shape, }; if let Err(e) = self .source .seek(SeekFrom::Start(header::HEADER_SIZE as u64)) { return Some(Err(Error::IoError(e))); } Some(Ok(shape)) } else { Some(Err(Error::MissingIndexFile)) } } /// Reads the `n`th shape of the shapefile pub fn read_nth_shape(&mut self, index: usize) -> Option<Result<Shape, Error>> { self.read_nth_shape_as::<Shape>(index) } } /// Function to read all the Shapes in a file. /// /// Returns a `Vec<Shape>` which means that you will have to `match` /// the individual [Shape](enum.Shape.html) contained inside the `Vec` to get the actual `struct` /// /// Useful if you don't know in advance (at compile time) which kind of /// shape the file contains /// /// # Examples /// /// ``` /// let shapes = shapefile::read("tests/data/multipatch.shp").unwrap(); /// assert_eq!(shapes.len(), 1); /// ``` pub fn read<T: AsRef<Path>>(path: T) -> Result<Vec<Shape>, Error> { let reader = Reader::from_path(path)?; reader.read() } /// Function to read all the Shapes in a file as a certain type /// /// Fails and return `Err(Error:MismatchShapeType)` /// /// # Examples /// /// ``` /// let polylines = shapefile::read_as::<_, shapefile::PolylineZ>("tests/data/polygon.shp"); /// assert_eq!(polylines.is_err(), true); /// /// let polygons = shapefile::read_as::<_, shapefile::Polygon>("tests/data/polygon.shp"); /// assert_eq!(polygons.is_ok(), true); /// ``` /// /// If the reading is successful, the returned `Vec<S:ReadShape>>`is a vector of actual structs /// Useful if you know in at compile time which kind of shape you expect the file to have pub fn read_as<T: AsRef<Path>, S: ReadableShape>(path: T) -> Result<Vec<S>, Error> { let reader = Reader::from_path(path)?; reader.read_as::<S>() } #[cfg(test)] mod tests {}