imagesize/formats/
ilbm.rs

1use crate::{
2    util::{read_u16, read_u32, Endian},
3    ImageResult, ImageSize,
4};
5use std::io::{BufRead, Seek, SeekFrom};
6
7pub fn size<R: BufRead + Seek>(reader: &mut R) -> ImageResult<ImageSize> {
8    // skip the IFF header
9    reader.seek(SeekFrom::Start(12))?;
10
11    let mut chunk_id = [0; 4];
12
13    loop {
14        reader.read_exact(&mut chunk_id)?;
15        let chunk_length = read_u32(reader, &Endian::Big)? as i64;
16
17        if &chunk_id == b"BMHD" {
18            return Ok(ImageSize {
19                width: read_u16(reader, &Endian::Big)? as usize,
20                height: read_u16(reader, &Endian::Big)? as usize,
21            });
22        }
23
24        // the BMHD chunk must occur before the BODY chunk
25        if &chunk_id == b"BODY" {
26            return Err(crate::ImageError::CorruptedImage);
27        }
28
29        // skip over the chunk; chunks of odd length have a padding byte
30        reader.seek(SeekFrom::Current(chunk_length + chunk_length % 2))?;
31    }
32}
33
34pub fn matches(header: &[u8]) -> bool {
35    header.len() >= 12
36        && &header[0..4] == b"FORM"
37        && (&header[8..12] == b"ILBM" || &header[8..12] == b"PBM ")
38}
imagesize/formats/ilbm.rs

imagesize/formats/
ilbm.rs
