Merge pull request #94 from rramphal/feat/djvu

feat: add support for DjVu image format

Author: bojand

README.md

@@ -5,11 +5,11 @@
 [![documentation](https://docs.rs/infer/badge.svg)](https://docs.rs/infer)
 
 Small crate to infer file and MIME type by checking the
-[magic number](https://en.wikipedia.org/wiki/Magic_number_(programming)) signature. 
+[magic number](https://en.wikipedia.org/wiki/Magic_number_(programming)) signature.
 
-Adaptation of [filetype](https://github.com/h2non/filetype) Go package ported to Rust. 
+Adaptation of [filetype](https://github.com/h2non/filetype) Go package ported to Rust.
 
-Does not require magic file database (i.e. `/etc/magic`). 
+Does not require magic file database (i.e. `/etc/magic`).
 
 ## Features
 
@@ -88,7 +88,7 @@ assert!(infer::is_image(&buf));
 ```
 
 ### Adds a custom file type matcher
-    
+
 ```rust
 fn custom_matcher(buf: &[u8]) -> bool {
     return buf.len() >= 3 && buf[0] == 0x10 && buf[1] == 0x11 && buf[2] == 0x12;
@@ -121,6 +121,7 @@ assert_eq!(kind.extension(), "foo");
 - **psd** - `image/vnd.adobe.photoshop`
 - **ico** - `image/vnd.microsoft.icon`
 - **ora** - `image/openraster`
+- **djvu** - `image/vnd.djvu`
 
 #### Video
 

src/map.rs

@@ -209,6 +209,12 @@ matcher_map!(
         "ora",
         matchers::image::is_ora
     ),
+    (
+        MatcherType::Image,
+        "image/vnd.djvu",
+        "djvu",
+        matchers::image::is_djvu
+    ),
     // Video
     (
         MatcherType::Video,

src/matchers/image.rs

@@ -194,6 +194,22 @@ pub fn is_ora(buf: &[u8]) -> bool {
         && buf[53] == 0x72
 }
 
+/// Returns whether a buffer is DjVu image data.
+pub fn is_djvu(buf: &[u8]) -> bool {
+    buf.len() > 14
+        && buf[0] == 0x41
+        && buf[1] == 0x54
+        && buf[2] == 0x26
+        && buf[3] == 0x54
+        && buf[4] == 0x46
+        && buf[5] == 0x4F
+        && buf[6] == 0x52
+        && buf[7] == 0x4D
+        && buf[12] == 0x44
+        && buf[13] == 0x4A
+        && buf[14] == 0x56
+}
+
 // GetFtyp returns the major brand, minor version and compatible brands of the ISO-BMFF data
 fn get_ftyp(buf: &[u8]) -> Option<(&[u8], &[u8], impl Iterator<Item = &[u8]>)> {
     if buf.len() < 16 {

testdata/sample_multi.djvu

@@ -29,3 +29,7 @@ test_format!(Image, "image/avif", "avif", avif, "sample.avif");
 test_format!(Image, "image/jxl", "jxl", jxl, "spline_on_first_frame.jxl");
 
 test_format!(Image, "image/openraster", "ora", ora, "sample.ora");
+
+test_format!(Image, "image/vnd.djvu", "djvu", djvu1, "sample_single.djvu");
+
+test_format!(Image, "image/vnd.djvu", "djvu", djvu2, "sample_multi.djvu");