VCLZipPro

[Christiaan]

I zipped the file test.txt with VCLZip Pro to test.zip. I can view the contents and extract the file in Winzip 8.1, but when I want to add another file or delete the test.txt from the archive, I get the following message:

Action: Delete
Include system and hidden files: yes
Warning: test.txt requires an unsupported zip compression scheme
Error: Unsupported compression scheme detected in Zip file.
Please see www.winzip.com/zip20.htm for more information. (C:\test.zip)

Does anybody know why?

[Kevin]

Apparently, for some reason, WinZip is bothered by the entry that VCLZip is putting into the VERSION_NEEDED_TO_EXTRACT field while PKZip is not bothered by this at all.

If you are a registered user, I can send you, via email, the modification you can make to the source code so that WinZip will not have a problem with this. It is just a small mod to one line of code.

I should also have a new version out no later than this weekend which will include this modification if you'd rather wait for that.

Thanks,

Kevin

[Christiaan]

Thanx for the quick response.

Delivery of our product is at the end of the month, so there is no big rush. I'll wait for the next version release.

regards,
Christiaan

[Kevin]

Sorry about that, it will be this week. I'm still playing catch up after the holidays.

[ged]

Hi Kevin

I tried to sent e-mail to [e-mail] but there was no answer
What about tech support ?

So I try here:

1. I made multivolume archive on a 3 CDs and when (for example) CD 1 is
damaged (scratched) VCLZip do OnGetNextDisk event first asking of CD 2
and after inserting CD 2 error is raising.
When last CD (3) is damaged - then VCLZip ask for CD 4 in OnGetNextDisk
event !

Problem is about line 169 of kpFile.pas i think
<code>
number_to_read := kpmin( file_info.compressed_size, LongInt(INBUFSIZ) );
file_info.compressed_size := file_info.compressed_size - number_to_read;
number_read := zip_in_file.Read( inbuf^, number_to_read );
incnt := number_read;
If (((ecrec.this_disk = 0))
and (incnt < number_to_read)) then
raise EFatalUnzipError.Create('Premature end of file reached');
tmpbuf := inbuf;
While (incnt < number_to_read) do {2/1/98 Changed If to While}
begin
zip_in_file := SwapDisk( CurrentDisk+2 );
</code>

zip_in_file.Read cannot read next block of data so incnt < number_to_read

VCLZip can't recognize difference between that erroneous situation and
normal disk swapping
How can i solve this problem ?

2. Suggestion:
It' would be good to add an error event with Retry var. When error
occurs during Unzip user has no possibility to decide : retry to Unzip
current item or not.
I know there is such a possibility in OnSkippingFile event but i don't
know how to use OnSkippingFile event in unzip error situations
Is it possible ?

3. Where can i find latest version of help file ? I found only old
version at vclzip.bizland.com/
It's not finished I think - example sections are empty

Best regards

Ged
[e-mail]

[Kevin]

Hi Ged,

Sorry I never saw an email from you. When did you send it?

1 and 2) I'll have to take a closer look at the code and see what might possibly be done.

3) As for the help file, the latest is what came with the latest version of VCLZip Pro. There are still empty example sections, that is because the help authoring tool put those in automatically and I have not removed all of the empty ones yet.

Kevin

[ged]

I send it twice:

Subject: CD multi-volume zip and unzip errors
Date: Thu, 06 Oct 2005 13:33:30 +0200
From: Pawel Jop <[e-mail]>
To: [e-mail]

Subject: [Fwd: CD multi-volume zip and unzip errors
Date: Fri, 07 Oct 2005 09:47:08 +0200
From: Paweł Jop <[e-mail]>
To: [e-mail]

I have no idea what's the problem.

But thanks for answer and I'll be waiting for solution of 1). and 2). It would be very helpful I think

Ged

[Kevin]

Ged,

I will take a closer look, and it can probably be cleaned up a bit, but the difficulty here is that there is no way to know whether "incnt < number_to_read" because of an error, or because the file is spanned across disks. Trying to get back to the right disk and file to "retry" a decompression can be complex, especially when there is a disk problem.

Kevin

[ged]

If I may suggest something - maybe try to do this that way:
Read filesize of current zip volume - for example var CurrentVolumeSize
Count amount of all processed data of this volume - for example var CurrentVolumeBytesProcessed.
Than during swapping disks You can check
if (CurrentVolumeSize=CurrentVolumeBytesProcessed)
If it's true You know that it's correct situation, if not - it's erroneous situation


Ged

[Kevin]

That is a possibility. I will consider that as I look through the code.

Kevin

[Andrew]

I have use an 3.05.32 version of your VCLZip. In the help file there written:

KB> OnEncrypt event
KB> Do not change the length of the buffer in any way. Essentially all that is allowed is a byte for byte replacement within the buffer.

But I want to increase the length of the buffer to use Rijndael block cipher. How can I do it?

[Kevin]

Andrew,

Unfortunately, I know of no way to do that.

Kevin