Re: zipping/unzipping library?

[Stefan Kost <ensonic hora-obscura de>]

Hi Allin,
Allin Cottrell wrote:
> Before I embark on this I'd like to find out if something of the sort 
> already exists, or if someone else is already working in this area.  
> Also, perhaps, how much interest there might be in this project.
>
> What I'm thinking would be useful is a library, with the portability 
> level of glib, offering the functionality of creating and extracting 
> files from zip archives.  I envisage it using both glib and zlib, and 
> offering a basic API with these elements:
>
> * A function to create a zip file, given a target filename, a list of 
> files to archive, and a compression level.
>
> * A function to retrieve a list of file attributes from a zip archive.
>
> * A function to extract all, or a selected list of, files from a zip 
> archive.
>
> This functionality is already present in the Infozip packages, zip and 
> unzip.  But although these packages contain some gestures toward 
> offering a library API, this has not been taken very far.  And although 
> the infozip programs work very nicely, the code is not pretty (for one 
> thing, it's choked with #ifdefs for every ancient architecture known to 
> man).
I was looking for similiar stuff and also found the infozip package. IMHO it 
would be extremly cool if someone could stuff this into handlers for gnome-vfs. 
Gnome-vfs is relative portable and does other nice things already. Right now I 
use gnome-vfs to store my application files (xml + binary data) in tar.gz 
archives. Uning a zip file would be prefered as a gzip-stream is not easy to 
recover in cases of bit-errors.

> The zlib API itself is fine; but it's quite low level, and it leaves the 
> application programmer to do much of the grunt work involved in creating 
> or reading a multi-file zipfile.
>
> One further comment: I can imagine the question, why bother with the 
> zipfile format when gzipped tar is better?  My response is that for 
> better or worse the PKzip format has become a de facto standard, now 
> enshrined in the ODF specs, and I'd like for my app to be able to read 
> and write ODF files.

Stefan