add streams step by step

[Harry]

Hi,
I've got a program processing files/objects in a recursive way. Now I'd like to add these to a zip as streams, but VCLZip does not allow this in a usable way. Every time I call ZipFromStream the whole zip gets recreated.
So I tried to derive from TVCLZip and add three methods like "beforeAddStream" AddStream" and "FinishedAddingStreams" using a copy of the code of the TVCLZip.ProcessFiles procedure, but with no success.
Do can help me? Or would you add such a feature?

[Kevin]

Hi Harry,

I'm not sure if this is what you are after or not, but there is an example project that uses ZipFromStream and OnGetNextStream to zip several streams into an archive. This OnGetNextStream allows you to zip several streams without recreating the archive each time.

Note that there are two examples. For D6 or D7 use:

www.vclzip.net/ongetnextstream.zip

for D4 or D5 use:

www.vclzip.net/ongetnextstreamd4d5.zip

When working with streams, D4 and D5 require that you use TkpHugeStreams, in this case TkpHugeMemorySteam, while in D6 and D7 you can use regular TStreams. This is because D6 and D7 TStreams have Int64 capabilities but D4 and D5 TStreams do not.

Kevin

[Harry]

Hi,
yes I know this.
But using the OnGetNextStream event is not possible if you like to add streams out of an recursive program structure.
Imagine you have a function recursively processing objects and for some special objects/subobjects you call a method "saveObjectStreamToZip". So only this method knows the stream to be currently zipped.
Using the OnGetNextStream event would mean this event needs to get a reference to the next stream of the recursive method which means that the recursive method must wait for the OnGetNextStream event respectively vice versa. This would be very complex especially because all this is already multithreadded.
My derived TVCLZipEx class adds this possibility by adding the three methods "beforeAddStream" AddStream" and "FinishedAddingStreams" using a copy of the code of the TVCLZip.ProcessFiles procedure and it works for creating new zip files. But I can't get it to work on existing zip files for replacing existing entries/files.
Would take a look at it?

[Kevin]

Sure, I will try to take a look at it.

Kevin

[Harry]

Thanks,
I just sent you mail with my TVCLZipEx unit as zipped attachment.

Harry

[Harry]

Hi,
how things did you find time for looking at my problem?

[Kevin]

Sorry, I have not had time to look at that. I have been really busy and that is a bit more complicated than I have had time to deal with.

Kevin

[anoa]

Hi Kevin,

I need this functionality too.
Do you have an idea when you will have time to look at it?

Peter.

[Kevin]

I have re-contacted Harry for more information and will be looking at it soon. Sorry for the slowness in looking at this, but this is something that will require a decent block of time to investigate.

Thanks,

Kevin

[Harry]

Hi Kevin,
I did send you a demo project on the 9th of Nov. 2006.
Did you receive it?
Did you find time to examine that problem?

Greetings

Harry

[Kevin]

Yes, I got it. Unfortunately we are out of sync. When you sent it I was working on another project. Well actually a VCLZip project, I was adding strong encryption to VCLZip.

I have just about finished that so I will hopefully get a chance to look at it soon. Sorry about the delay.

Kevin

[Harry]

Hi,
more than half a year ago...
what's about this?
Did you find time to have a closer look on this?

Harry

[Harry]

Hi,
nice to see you back.
What about that feature here?
Will it be included in VCLZip 3.1 or 4.0?

Greetings

Harry

[Kevin]

Hi Harry,

Version 3.1 will pretty much just be bug fixes and performance improvements (memory usage). Version 4.0 will definitely include strong encryption. We'd like to get that out by years end and don't want to slow that release down, so incrementally adding streams would be a good possibility for version 4.1.

Kevin