Add XBM decoder

Author: mstoeckl

Cargo.toml

@@ -8,8 +8,9 @@ publish = false
 include = ["src", "tests/reference.rs"]
 
 [features]
-default = ["pcx"]
+default = ["pcx", "xbm"]
 pcx = ["dep:pcx"]
+xbm = []
 
 [dependencies]
 image = { version = "0.25.5", default-features = false }

README.md

@@ -6,6 +6,7 @@ Decoding support for additional image formats beyond those provided by the [`ima
 | Extension | File Format Description |
 | --------- | -------------------- |
 | PCX | [Wikipedia](https://en.wikipedia.org/wiki/PCX#PCX_file_format) |
+| XBM | [Wikipedia](https://en.wikipedia.org/wiki/X_BitMap) |
 
 ## New Formats
 

examples/convert.rs

@@ -13,6 +13,7 @@ fn make_decoder(path: &Path) -> Result<Box<dyn ImageDecoder>, Box<dyn Error>> {
     let reader = BufReader::new(File::open(path)?);
     Ok(match path.extension().and_then(|p| p.to_str()) {
         Some("pcx") => Box::new(image_extras::pcx::PCXDecoder::new(reader)?),
+        Some("xbm") => Box::new(image_extras::xbm::XbmDecoder::new(reader)?),
         _ => Box::new(ImageReader::new(reader).into_decoder()?),
     })
 }

fuzz/Cargo.toml

@@ -13,10 +13,14 @@ cargo-fuzz = true
 image = { version = "0.25.5", default-features = false }
 [dependencies.image-extras]
 path = ".."
-features = []
+features = ["xbm"]
 [dependencies.libfuzzer-sys]
 version = "0.3"
 
 # Prevent this from interfering with workspaces
 [workspace]
 members = ["."]
+
+[[bin]]
+name = "fuzzer_script_xbm"
+path = "fuzzers/fuzzer_script_xbm.rs"

fuzz/README.md

@@ -4,3 +4,7 @@ For the possibly more up-to-date guide see <https://fuzz.rs/book/cargo-fuzz/setu
 
 > $ cargo install cargo-fuzz
 > $ cargo +nightly fuzz run fuzzer_script_<format>
+
+Fuzzing may progress faster for certain formats if seeded with a dictionary:
+
+> $ cargo +nightly fuzz run fuzzer_script_xbm -- -dict=fuzz/dictionaries/xbm.dict

fuzz/dictionaries/xbm.dict

@@ -0,0 +1,16 @@
+"#define"
+"_width"
+"_height"
+"_x_hot"
+"_y_hot"
+"static"
+"unsigned"
+"char"
+"_bits[]"
+"="
+"{"
+"0x"
+"0X"
+","
+"}"
+";"

fuzz/fuzzers/fuzzer_script_xbm.rs

@@ -0,0 +1,24 @@
+#![no_main]
+#[macro_use]
+extern crate libfuzzer_sys;
+extern crate image_extras;
+extern crate image;
+
+use std::io::BufReader;
+use image::ImageDecoder;
+
+fuzz_target!(|data: &[u8]| {
+    let reader = BufReader::new(data);
+    let Ok(mut decoder) = image_extras::xbm::XbmDecoder::new(reader) else {
+        return;
+    };
+    let mut limits = image::Limits::default();
+    limits.max_alloc = Some(1024 * 1024); // 1 MiB
+    if limits.reserve(decoder.total_bytes()).is_err() {
+        return;
+    }
+    if decoder.set_limits(limits).is_err() {
+        return;
+    }
+    let _ = std::hint::black_box(image::DynamicImage::from_decoder(decoder));
+});

src/lib.rs

@@ -18,6 +18,9 @@
 #[cfg(feature = "pcx")]
 pub mod pcx;
 
+#[cfg(feature = "xbm")]
+pub mod xbm;
+
 /// Register all enabled extra formats with the image crate.
 pub fn register() {
     // NOTE: https://github.com/image-rs/image/pull/2372