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use std::fs::File; use std::path::Path; use std::io::Read; use std::io::{BufRead, BufReader, Seek}; #[cfg(test)] mod tests { use *; #[test] fn bmp_test() { match get_dimensions("test/test.bmp") { Ok(dim) => { assert_eq!(dim.width, 512); assert_eq!(dim.height, 512); } Err(why) => println!("Error getting dimensions: {:?}", why) } } #[test] fn gif_test() { match get_dimensions("test/test.gif") { Ok(dim) => { assert_eq!(dim.width, 100); assert_eq!(dim.height, 100); } Err(why) => println!("Error getting dimensions: {:?}", why) } } #[test] fn jpeg_test() { match get_dimensions("test/test.jpg") { Ok(dim) => { assert_eq!(dim.width, 690); assert_eq!(dim.height, 298); } Err(why) => println!("Error getting dimensions: {:?}", why) } } #[test] fn png_test() { match get_dimensions("test/test.png") { Ok(dim) => { assert_eq!(dim.width, 2000); assert_eq!(dim.height, 2000); } Err(why) => println!("Error getting dimensions: {:?}", why) } } #[test] fn webp_test() { match get_dimensions("test/test.webp") { Ok(dim) => { assert_eq!(dim.width, 716); assert_eq!(dim.height, 716); } Err(why) => println!("Error getting dimensions: {:?}", why) } } } pub enum ImageType { BMP, GIF, JPEG, PNG, WEBP, } #[derive(Debug)] pub enum ImageError { NotSupported(String), IoError(std::io::Error), } impl From<std::io::Error> for ImageError { fn from(err: std::io::Error) -> ImageError { ImageError::IoError(err) } } pub type ImageResult<T> = Result<T, ImageError>; pub struct Dimensions { pub width: usize, pub height: usize, } pub fn get_dimensions<P>(path: P) -> ImageResult<Dimensions> where P: AsRef<Path> { let file = try!(File::open(path)); let mut reader = BufReader::new(file); let mut header = [0; 1]; try!(reader.read_exact(&mut header)); match header[0] { 0xFF => get_jpeg_dimensions(&mut reader), 0x89 => get_png_dimensions(&mut reader), b'R' => get_webp_dimensions(&mut reader), b'G' => get_gif_dimensions(&mut reader), b'B' => get_bmp_dimensions(&mut reader), _ => Err(ImageError::NotSupported("Could not decode image.".to_owned())) } } fn get_bmp_dimensions(reader: &mut BufReader<File>) -> ImageResult<Dimensions> { let mut buffer = [0; 8]; try!(reader.seek(std::io::SeekFrom::Start(0x12))); try!(reader.read_exact(&mut buffer)); Ok(Dimensions { width: ((buffer[0] as usize) | ((buffer[1] as usize) << 8) | ((buffer[2] as usize) << 16) | ((buffer[3] as usize) << 24)), height: ((buffer[4] as usize) | ((buffer[5] as usize) << 8) | ((buffer[6] as usize) << 16) | ((buffer[7] as usize) << 24)) }) } fn get_gif_dimensions(reader: &mut BufReader<File>) -> ImageResult<Dimensions> { let mut buffer = [0; 4]; try!(reader.seek(std::io::SeekFrom::Start(6))); try!(reader.read_exact(&mut buffer)); Ok(Dimensions { width: ((buffer[0] as usize) | ((buffer[1] as usize) << 8)), height: ((buffer[2] as usize) | ((buffer[3] as usize) << 8)) }) } fn get_jpeg_dimensions(reader: &mut BufReader<File>) -> ImageResult<Dimensions> { let mut search = Vec::new(); let mut buffer = [0; 4]; let mut page = [0; 1]; loop { let _ = try!(reader.read_until(0xFF, &mut search)); try!(reader.take(1).read(&mut page)); if page[0] == 0xC0 { try!(reader.seek(std::io::SeekFrom::Current(3))); break; } } try!(reader.read_exact(&mut buffer)); Ok(Dimensions { width: ((buffer[3] as usize) | ((buffer[2] as usize) << 8)), height: ((buffer[1] as usize) | ((buffer[0] as usize) << 8)) }) } fn get_png_dimensions(reader: &mut BufReader<File>) -> ImageResult<Dimensions> { let mut buffer = [0; 8]; try!(reader.seek(std::io::SeekFrom::Start(16))); try!(reader.read_exact(&mut buffer)); Ok(Dimensions { width: ((buffer[3] as usize) | ((buffer[2] as usize) << 8) | ((buffer[1] as usize) << 16) | ((buffer[0] as usize) << 24)), height: ((buffer[7] as usize) | ((buffer[6] as usize) << 8) | ((buffer[5] as usize) << 16) | ((buffer[4] as usize) << 24)) }) } fn get_webp_dimensions(reader: &mut BufReader<File>) -> ImageResult<Dimensions> { let mut buffer = [0; 6]; try!(reader.seek(std::io::SeekFrom::Start(0x18))); try!(reader.read_exact(&mut buffer)); Ok(Dimensions { width: ((buffer[0] as usize) | ((buffer[1] as usize) << 8) | ((buffer[2] as usize) << 16)) + 1, height: ((buffer[3] as usize) | ((buffer[4] as usize) << 8) | ((buffer[5] as usize) << 16)) + 1 }) }