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[7.3.1] Zlib problem. BUG ?

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Mark Pirogovsky-3

[7.3.1] Zlib problem. BUG ?

Hello All,

I started using the OS.ZLib.GZipWriteStream/GZipReadStream extensively
lately and I came across some anomaly.

Sometimes, without any apparent reason the compression fails trying to
create CRC. and if I proceed with the writing, then the resultant file
will cause an error while reading it on the account of empty CRC
information.

Interestingly, if I use the WinZip or WinRar - those can open the
compressed file and show the appropriate contents.

Any Idea anyone ?

here is the hint - the compression fails reliably if the part of the
file was already compressed somehow. I think it is a BUG.

--Mark

Mark Pirogovsky-3

Re: [7.3.1] Zlib problem. BUG ?

Hi List,

Sorry to bug everybody again....

Does anybody have any Idea about zlib interface CRC failures ?

It is getting to the point where I have to abandon using it and look for
some third party DLL to use.

It is no fun to start using the feature provided by the vendor, just to
discover that it does not work 100%.

I'd rather don't have it at all.

--Mark

Mark Pirogovsky wrote:

> Hello All,
>
> I started using the OS.ZLib.GZipWriteStream/GZipReadStream extensively
> lately and I came across some anomaly.
>
> Sometimes, without any apparent reason the compression fails trying to
> create CRC. and if I proceed with the writing, then the resultant file
> will cause an error while reading it on the account of empty CRC
> information.
>
> Interestingly, if I use the WinZip or WinRar - those can open the
> compressed file and show the appropriate contents.
>
> Any Idea anyone ?
>
> here is the hint - the compression fails reliably if the part of the
> file was already compressed somehow. I think it is a BUG.
>
>
> --Mark
>
>
>

Bob Westergaard-2

Re: [7.3.1] Zlib problem. BUG ?

On Fri, 9 Jun 2006, Mark Pirogovsky wrote:

> Hi List,
>
> Sorry to bug everybody again....
>
> Does anybody have any Idea about zlib interface CRC failures ?
>
> It is getting to the point where I have to abandon using it and look for
> some third party DLL to use.
>
> It is no fun to start using the feature provided by the vendor, just to
> discover that it does not work 100%.
>
> I'd rather don't have it at all.

I haven't read your original email message, so forgive me for possibly
creating confusion.

I seem to recall us fixing a problem with the Zlib code not too long ago.
A quick look at the fixed_ars.txt list for 7.4 shows that there was
something fixed (48854 OS.ZLib.DeflateStream>>writeBuffer: treats
Z_BUF_ERROR as a fatal error).

Can you try the 7.4 version and see if that fixes the problem? If not,
then can you provide simple test that can reproduce the problem, and I'll
see what we can do.