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December 2005

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2005.12.13 18:20 "read and write image with same TIFF handle", by Eugene Shebeko
2005.12.13 21:39 "Re: read and write image with same TIFF handle", by Andrey Kiselev
2005.12.13 21:55 "Re: read and write image with same TIFF handle", by Frank Warmerdam
2005.12.15 09:11 "Re: read and write image with same TIFF handle", by Eugene Shebeko
2005.12.29 23:18 "Re: read and write image with same TIFF handle", by Andrey Kiselev

2005.12.13 21:55 "Re: read and write image with same TIFF handle", by Frank Warmerdam

On 12/13/05, ϋΕΒΕΛΟ εΧΗΕΞΙΚ wrote:
>
> As I see, I cann't to read and write image data in one session, i.e.
> using one TIFF handle.
> The problem in codec's setup. There are only one flags in libtiff
> TIFF_CODERSETUP that indicate that codec inited for decode, or code process
> (tif->tif_setupdecode,tif->tif_setupencode)
>
> First call TIFFReadTile() for example codec setup for decode.
> Then later TIFFWriteTile() but TIFF_CODERSETUP still set and
> tif->tif_setupencode never called.
> As a result libtiff crash in codec.
>
> Is it known problem?

ϋΕΒΕΛΟ,

I have experienced similar issues.

> Is in plans to fix it?
> Is problem with codec is only one problem to read and write image
> with same TIFF handle?

Reading and writing an image with the same handle opened in
update mode is supported fine for uncompressed images, so I
believe the problem is only related to the compression codecs.

> Actually I can to fix it itself.
> It is not dificult replace TIFF_CODERSETUP with 2 flags
> TIFF_CODERSETUP, TIFF_DECODERSETUP and to control in initialization
> code that only one flag could be set.
>
> 2. question
> When next version of libtiff are expected?
> If I make some useful changes in libtiff may I expect that this
> changes will be included in libtiff? And how can I do it?

This is a very fragile aspect of the code.  While we would
appreciate a carefully constructed patch, I am personally
very concerned about unintended consequences and if
we can't make ourselves comfortable with the patch, it
won't be applied to the core library.

Best regards,

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