Merge pull request #36 from KateMorley/ilbm

Add support for ILBM

Author: Roughsketch

README.md

@@ -23,6 +23,7 @@ imagesize = "0.12"
 * HDR
 * HEIC / HEIF
 * ICO*
+* ILBM (IFF)
 * JPEG
 * JPEG XL
 * KTX2

src/formats/ilbm.rs

@@ -0,0 +1,38 @@
+use crate::{
+    util::{read_u16, read_u32, Endian},
+    ImageResult, ImageSize,
+};
+use std::io::{BufRead, Seek, SeekFrom};
+
+pub fn size<R: BufRead + Seek>(reader: &mut R) -> ImageResult<ImageSize> {
+    // skip the IFF header
+    reader.seek(SeekFrom::Start(12))?;
+
+    let mut chunk_id = [0; 4];
+
+    loop {
+        reader.read_exact(&mut chunk_id)?;
+        let chunk_length = read_u32(reader, &Endian::Big)? as i64;
+
+        if &chunk_id == b"BMHD" {
+            return Ok(ImageSize {
+                width: read_u16(reader, &Endian::Big)? as usize,
+                height: read_u16(reader, &Endian::Big)? as usize,
+            });
+        }
+
+        // the BMHD chunk must occur before the BODY chunk
+        if &chunk_id == b"BODY" {
+            return Err(crate::ImageError::CorruptedImage);
+        }
+
+        // skip over the chunk; chunks of odd length have a padding byte
+        reader.seek(SeekFrom::Current(chunk_length + chunk_length % 2))?;
+    }
+}
+
+pub fn matches(header: &[u8]) -> bool {
+    header.len() >= 12
+        && &header[0..4] == b"FORM"
+        && (&header[8..12] == b"ILBM" || &header[8..12] == b"PBM ")
+}

src/formats/mod.rs

@@ -8,6 +8,7 @@ pub mod gif;
 pub mod hdr;
 pub mod heif;
 pub mod ico;
+pub mod ilbm;
 pub mod jpeg;
 pub mod jxl;
 pub mod ktx2;
@@ -116,6 +117,10 @@ pub fn image_type<R: BufRead + Seek>(reader: &mut R) -> ImageResult<ImageType> {
         return Ok(ImageType::Vtf);
     }
 
+    if ilbm::matches(&header) {
+        return Ok(ImageType::Ilbm);
+    }
+
     // Keep TGA last because it has the highest probability of false positives
     if tga::matches(&header, reader) {
         return Ok(ImageType::Tga);

src/lib.rs

@@ -66,6 +66,8 @@ pub enum ImageType {
     Heif,
     /// Icon file
     Ico,
+    /// Interleaved Bitmap
+    Ilbm,
     /// Standard JPEG
     Jpeg,
     /// JPEG XL
@@ -257,6 +259,7 @@ fn dispatch_header<R: BufRead + Seek>(reader: &mut R) -> ImageResult<ImageSize>
         ImageType::Hdr => hdr::size(reader),
         ImageType::Heif => heif::size(reader),
         ImageType::Ico => ico::size(reader),
+        ImageType::Ilbm => ilbm::size(reader),
         ImageType::Jpeg => jpeg::size(reader),
         ImageType::Jxl => jxl::size(reader),
         ImageType::Ktx2 => ktx2::size(reader),

tests/ilbm.rs

@@ -0,0 +1,13 @@
+#[cfg(test)]
+use imagesize::{size, ImageSize};
+
+#[test]
+fn ilbm_test() {
+    assert_eq!(
+        size("tests/images/ilbm/test.iff").unwrap(),
+        ImageSize {
+            width: 640,
+            height: 512
+        }
+    );
+}