From 002b9037a21d488f993beba86d5dff09d0e1be85 Mon Sep 17 00:00:00 2001
From: Fabio Perrella <fabio.perrella@gmail.com>
Date: Thu, 10 Sep 2020 15:56:59 -0300
Subject: [PATCH] Does not raise error when it has invalid thumbails data (#65)

Signed-off-by: Remco van 't Veer <remco@remworks.net>
---
 lib/exifr/tiff.rb | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/lib/exifr/tiff.rb b/lib/exifr/tiff.rb
index 948a575b..8f6c2f10 100644
--- a/lib/exifr/tiff.rb
+++ b/lib/exifr/tiff.rb
@@ -384,7 +384,12 @@ def initialize(file)
         @jpeg_thumbnails = @ifds.map do |v|
           if v.jpeg_interchange_format && v.jpeg_interchange_format_length
             start, length = v.jpeg_interchange_format, v.jpeg_interchange_format_length
-            data[start..(start + length)]
+            if Integer === start && Integer === length
+              data[start..(start + length)]
+            else
+              EXIFR.logger.warn("Non numeric JpegInterchangeFormat data")
+              nil
+            end
           end
         end.compact
       end