Handle tiff format with long dimension values, fixes #158

sdsykes · Jan 2, 2025 · cad7175 · cad7175
1 parent a891d8f
commit cad7175
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Showing 3 changed files with 11 additions and 3 deletions.
diff --git a/lib/fastimage/fastimage_parsing/exif.rb b/lib/fastimage/fastimage_parsing/exif.rb
@@ -30,8 +30,16 @@ def parse_exif_ifd
       tag_count = @stream.read(2).unpack(@short)[0]
       tag_count.downto(1) do
         type = @stream.read(2).unpack(@short)[0]
-        @stream.read(6)
-        data = @stream.read(2).unpack(@short)[0]
+        data_type = @stream.read(2).unpack(@short)[0]
+        @stream.read(4)
+
+        if data_type == 4
+          data = @stream.read(4).unpack(@long)[0]
+        else
+          data = @stream.read(2).unpack(@short)[0]
+          @stream.read(2)
+        end
+
         case type
         when 0x0100 # image width
           @width = data
@@ -43,7 +51,6 @@ def parse_exif_ifd
         if @width && @height && @orientation
           return # no need to parse more
         end
-        @stream.read(2)
       end
     end
 

diff --git a/test/fixtures/test.dng b/test/fixtures/test.dng
diff --git a/test/test.rb b/test/test.rb
@@ -60,6 +60,7 @@
   "avif/red_green_flash.avif" => [:avif, [256, 256]],
   "isobmff.jxl" => [:jxl, [1280,1600]],
   "naked.jxl" => [:jxl, [1000,1000]],
+  "test.dng" => [:tiff, [4032, 3024]]
 }
 
 BadFixtures = [