Zip Header... A few questions

[torels]

Hi there

I have a few questions on how to read, modify ect a zip file's header (after the PK and 18 nul chars)

Here is some reference:

http://www.pkware.com/documents/casestudies/APPNOTE.TXT

http://www.ta7.de/txt/computer/computer016.htm

what I basicly need is to learn/understand how to manage the data in the header

i want to be able to delete files (by deleting the actual code in the file) and then modify the size part and the crc23 part of the header so the zip won't result broken

thanks in advance

[PsaltyDS]

Hi there

I have a few questions on how to read, modify ect a zip file's header (after the PK and 18 nul chars)

Here is some reference:

http://www.pkware.com/documents/casestudies/APPNOTE.TXT

http://www.ta7.de/txt/computer/computer016.htm

what I basicly need is to learn/understand how to manage the data in the header

i want to be able to delete files (by deleting the actual code in the file) and then modify the size part and the crc23 part of the header so the zip won't result broken

thanks in advance

You are re-inventing the wheel. There are APIs to work with .zip files without trying to create your own. For example, eltorro's: Zip plugin, A plugin to add zip function to AutoIt V3

There is also a .dll interface to 7-zip, etc., etc., ...

[trancexx]

weaponx had a nice code to read zip files. Link to that.

...regardless of PsaltyDS's (is this ok?) remark, I think you should go for it.

[PsaltyDS]

weaponx had a nice code to read zip files. Link to that.

...regardless of PsaltyDS's (is this ok?) remark, I think you should go for it.

The code linked above does not modify the file, which is the tricky part. I believe there would be indexes and checksums elsewhere in the file that would have to updated too, or the file would just be flagged as corrupt by the usual APIs.

7-zip is open source. If this is an educational exercise (you want to learn how the other programs do it) then you should look inside that source code for an example of how it was done. In this case, examining other wheels, then re-inventing the wheel is a good thing because you learn so much about wheels in the process.

If this is a practical matter (you want to achieve this operation efficiently in an AutoIt script), then re-inventing the wheel is an absurd waste of time, because there are serviceable wheels laying around all over the place.

[trancexx]

Yes of course.

Wheels to learn from.

Btw, weaponx covered all available data. There is no more.

[torels]

I know of those APIs, but I wanted to do it in au3

thanks alot trancexx