fn read(file:&mut dyn Read) -> Result<Option<Chunk>, ChunkReadError> {
		let mut size:[u8;4] = [0,0,0,0];
		let (mut size_head, mut size_tail) = size.split_at_mut(1);
		if let Err(e) = file.read_exact(&mut size_head) {
			if e.kind() == ErrorKind::UnexpectedEof {
				return Ok(None)
			} else {
				return Err(ChunkReadError::Io(e))
			}
		}
		file.read_exact(&mut size_tail).map_err(ChunkReadError::Io).and_then(|_| {
			let size = u32::from_be_bytes(size);

			let mut typ:[u8;4] = [0,0,0,0];
			file.read_exact(&mut typ).map_err(ChunkReadError::Io).and_then(|_| {
				let typ = typ;

				if ! typ.iter().all(|c| (0x41 <= *c && *c <= 0x5A) || (0x61 <= *c && *c <= 0x7A)) {
					Err(ChunkReadError::InvalidTyp(typ))
				} else {
					let mut data:Vec<u8> = vec![0; u32_to_usize(size)];
					file.read_exact(&mut data).map_err(ChunkReadError::Io).and_then(|_| {
						let data = data;

						let mut stated_crc:[u8;4] = [0; 4];
						file.read_exact(&mut stated_crc).map_err(ChunkReadError::Io).and_then(|_| {
							let stated_crc = u32::from_be_bytes(stated_crc);
							let cacluated_crc = calculate_crc(typ.iter().chain(data.iter()));

							if stated_crc == cacluated_crc {
								Ok(Some(Chunk{typ, data}))
							} else {
								Err(ChunkReadError::CrcMismatch{stated:stated_crc, calculated:cacluated_crc})
							}
						})
					})
				}
			})
		})
	}
/// Reads a PNG chunk from a data stream
Reads a PNG chunk from a data stream
Reads a PNG chunk from a data stream
fn read(file:&mut dyn Read) -> Result<Option<Chunk>, ChunkReadError> {
		let mut size:[u8;4] = [0,0,0,0];
		let (mut size_head, mut size_tail) = size.split_at_mut(1);
		if let Err(e) = file.read_exact(&mut size_head) {
			if e.kind() == ErrorKind::UnexpectedEof {
				return Ok(None)
			} else {
				return Err(ChunkReadError::Io(e))
			}
		}
		file.read_exact(&mut size_tail).map_err(ChunkReadError::Io).and_then(|_| {
			let size = u32::from_be_bytes(size);
			let mut typ:[u8;4] = [0,0,0,0];
			file.read_exact(&mut typ).map_err(ChunkReadError::Io).and_then(|_| {
				let typ = typ;
				if ! typ.iter().all(|c| (0x41 <= *c && *c <= 0x5A) || (0x61 <= *c && *c <= 0x7A)) {
					Err(ChunkReadError::InvalidTyp(typ))
				} else {
					let mut data:Vec<u8> = vec![0; u32_to_usize(size)];
					file.read_exact(&mut data).map_err(ChunkReadError::Io).and_then(|_| {
						let data = data;
						let mut stated_crc:[u8;4] = [0; 4];
						file.read_exact(&mut stated_crc).map_err(ChunkReadError::Io).and_then(|_| {
							let stated_crc = u32::from_be_bytes(stated_crc);
							let cacluated_crc = calculate_crc(typ.iter().chain(data.iter()));
							if stated_crc == cacluated_crc {
								Ok(Some(Chunk{typ, data}))
							} else {
								Err(ChunkReadError::CrcMismatch{stated:stated_crc, calculated:cacluated_crc})
							}
						})
					})
				}
			})
		})
	}
fn read ( file : & mut dyn Read ) -> Result < Option < Chunk > , ChunkReadError > { let mut size : [ u8 ; 4 ] = [ 0 , 0 , 0 , 0 ] ; let ( mut size_head , mut size_tail ) = size . split_at_mut ( 1 ) ; if let Err ( e ) = file . read_exact ( & mut size_head ) { if e . kind ( ) == ErrorKind :: UnexpectedEof { return Ok ( None ) } else { return Err ( ChunkReadError :: Io ( e ) ) } } file . read_exact ( & mut size_tail ) . map_err ( ChunkReadError :: Io ) . and_then ( | _ | { let size = u32 :: from_be_bytes ( size ) ; let mut typ : [ u8 ; 4 ] = [ 0 , 0 , 0 , 0 ] ; file . read_exact ( & mut typ ) . map_err ( ChunkReadError :: Io ) . and_then ( | _ | { let typ = typ ; if ! typ . iter ( ) . all ( | c | ( 0x41 <= * c && * c <= 0x5A ) || ( 0x61 <= * c && * c <= 0x7A ) ) { Err ( ChunkReadError :: InvalidTyp ( typ ) ) } else { let mut data : Vec < u8 > = vec ! [ 0 u32_to_usize ( size ) ] ; file . read_exact ( & mut data ) . map_err ( ChunkReadError :: Io ) . and_then ( | _ | { let data = data ; let mut stated_crc : [ u8 ; 4 ] = [ 0 ; 4 ] ; file . read_exact ( & mut stated_crc ) . map_err ( ChunkReadError :: Io ) . and_then ( | _ | { let stated_crc = u32 :: from_be_bytes ( stated_crc ) ; let cacluated_crc = calculate_crc ( typ . iter ( ) . chain ( data . iter ( ) ) ) ; if stated_crc == cacluated_crc { Ok ( Some ( Chunk { typ , data } ) ) } else { Err ( ChunkReadError :: CrcMismatch { stated : stated_crc , calculated : cacluated_crc } ) } } ) } ) } } ) } ) }
Reads a PNG chunk from a data stream
Reads a PNG chunk from a data stream
file
&mut dyn Read