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April 2017

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2017.04.28 20:38 "Interesting change/problem in LibTiff 4.0.7 with unsupported compressions", by <massoft@massoftware.com>
2017.05.02 12:56 "Re: Interesting change/problem in LibTiff 4.0.7 with unsupported compressions", by Michael Shiels
2017.05.02 14:33 "Re: Interesting change/problem in LibTiff 4.0.7 with unsupported compressions", by Charles Auer

2017.05.02 12:56 "Re: Interesting change/problem in LibTiff 4.0.7 with unsupported compressions", by Michael Shiels

Just wondering if anyone has thoughts on this problem.  Once I posted it
doesn't' seem to have made it into the archive which means maybe it didn't
get through at all??

 

This is a interesting situation since most people don't expect an error just
from enumerating the directory and reading the tags.  Maybe a warning would
be more appropriate specifically for an inability to detail out the
compression specific tags maybe??

 

Thanks.

Mike

 

From: tiff-bounces@lists.maptools.org
[mailto:tiff-bounces@lists.maptools.org] On Behalf Of Michael | Shiels [ MaS
\ Software \ Inc ]
Sent: Friday, April 28, 2017 4:38 PM
To: tiff@lists.maptools.org
Subject: [Tiff] Interesting change/problem in LibTiff 4.0.7 with unsupported
compressions

 

I found a decent change in the behavior of Libtiff - after I updated from
the 3.5.6/3.5.7 era to the most recent (yes 15 year jump!!)

 

Specifically this piece of code - basically ends up tripping an error if the
compression is not compiled/activated in the code.  So you can't even
peruse/move through a file without tripping an error.

 

               /*

               * An opportunity for compression mode dependent tag fixup

               */

               (*tif->tif_fixuptags)(tif);

 

 

Our engine specifically watches for errors and assumes it's pretty fatal -
when really it's kinda benign - UNLESS I want to extract the image data
itself, right??

 

Surely that should be pretty benign to just enumerate through a TIFF - even
if you don't support the compression of each page??

 

Mike