diff options
| author | R. N. West <[email protected]> | 2025-08-15 17:43:17 +0100 |
|---|---|---|
| committer | John MacFarlane <[email protected]> | 2025-08-15 22:27:04 -0700 |
| commit | 42f0280854123c9f47b760bf36f6cce03fe6501a (patch) | |
| tree | 8819165af4c2c697cb6a8d47d43718546b6fde41 | |
| parent | 4b01fd700af53743703d90bf5b8cee3be57e40d3 (diff) | |
ImageSize: Fix JPEG file signature detection.
The previous implementation didn't include all possible JPEG file
signatures. All signatures in the range of ff d8 ff e0 and ff d8 ff ef
should be valid, in addition to ff d8 ff db (no application segment).
See <https://gist.github.com/leommoore/f9e57ba2aa4bf197ebc5?permalink_comment_id=3863054#gistcomment-3863054>
and p. 32 of <https://www.w3.org/Graphics/JPEG/itu-t81.pdf>.
| -rw-r--r-- | src/Text/Pandoc/ImageSize.hs | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/src/Text/Pandoc/ImageSize.hs b/src/Text/Pandoc/ImageSize.hs index 11b2ecf53..ec2ee0c75 100644 --- a/src/Text/Pandoc/ImageSize.hs +++ b/src/Text/Pandoc/ImageSize.hs @@ -61,7 +61,6 @@ import Codec.Compression.Zlib (decompress) -- import Debug.Trace -- quick and dirty functions to get image sizes --- algorithms borrowed from wwwis.pl data ImageType = Png | Gif | Jpeg | Svg | Pdf | Eps | Emf | Tiff | Webp | Avif deriving Show @@ -119,9 +118,11 @@ imageType img = case B.take 4 img of "\x47\x49\x46\x38" -> return Gif "\x49\x49\x2a\x00" -> return Tiff "\x4D\x4D\x00\x2a" -> return Tiff - "\xff\xd8\xff\xe0" -> return Jpeg -- JFIF - "\xff\xd8\xff\xe1" -> return Jpeg -- Exif - "\xff\xd8\xff\xee" -> return Jpeg -- Exif see #11049 + "\xff\xd8\xff\xbd" -> return Jpeg -- JPEG without application segment -- see p.32 in https://www.w3.org/Graphics/JPEG/itu-t81.pdf (and https://gist.github.com/leommoore/f9e57ba2aa4bf197ebc5?permalink_comment_id=3863054#gistcomment-3863054) + _ | B.take 3 img == "\xff\xd8\xff" + && (let byte4 = B.take 1 (B.drop 3 img) + in byte4 >= "\xe0" && byte4 <= "\xef") -- JPEG with application segment + -> return Jpeg "%PDF" -> return Pdf "<svg" -> return Svg "<?xm" |