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TIFF and LibTiff Mail List Archive

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2006.09.20 13:46 "[Tiff] .h.vc filename changes", by Frank Warmerdam
2006.09.27 22:45 "[Tiff] tif_lzw, tif_zip - mixing reading and writing", by Frank Warmerdam

2006.09.27 22:45 "[Tiff] tif_lzw, tif_zip - mixing reading and writing", by Frank Warmerdam

Folks,

First, let me apologize for not being very involved with the mailing list or active in libtiff maintenance lately. I really appreciate the work that Andrey and Joris are doing - especially how often Joris takes care of complicated questions on the list.

But my main point, is that I have made some subtle changes in tif_lzw.c, and tif_zip.c in CVS that attempt to make mixing of read and write activity for compressed TIFF files work better. In the past it was assumed that a TIFF* was either in read only or in write mode but never a mixture. Several years ago I attempted to incorporate support for opening files in update (read/write) mode. Despite some shortcomings it generally worked ok for uncompressed files. But the compression codec generally made assumptions that were broken by this new update mode.

I think this was fixed for packbits a while ago. Today I *think* I have correctly fixed it for deflate/zip compression and lzw compression. I am pretty sure though that the problem remains for jpeg compression. I haven't checked any of the other codecs which I think are much less commonly used.

So this email is a warning to folks to test and keep this change in mind as a possible source of new bugs.

Best regards,
--
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam@pobox.com
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