Re: ZIP archives

FROM : Ryan Britton
DATE : Wed Jul 26 01:02:40 2006

Bottom line:  There is no library support for the full ZIP file 
specification.  Zlib is included with the system, but it has the 
limitation of only being able to process single files directly. 
You'll either need to write your own code (I'm aware of no public 
implementations) or wrap something such as ditto and incur the 
process-starting overhead.

I am working on implementing the ZIP standard for my own needs in a 
framework and may make that framework public at some point, but it is 
not nearly complete.

ZIP Spec:  http://www.pkware.com/business_and_developers/developer/
popups/appnote.txt


On Jul 25, 2006, at 3:44 PM, Michael Hall wrote:

>
> On Jul 25, 2006, at 5:24 PM, Matt Mashyna wrote:
>

>>  You need to
>> make a function to get the file time and attributes, and a 
>> function to
>> calculate the MacBinary CRC.
>>

>
> I thought someone a while back had indicated a semi-standard 
> wrapper for zlib zip access in Cocoa. I might be misremembering.
> Nitpicking. The CRC16 or more probably CRC32 are included in the 
> zip spec's I think and have nothing to do with MacBinary. That 
> might be added if you were supporting Classical era resource forks. 
> For example a 3rd party shareware package called ZipIt used to 
> encode the file signature meta information and resource fork data 
> using MacBinary in the user field of the zip file header.
> I did a classical zlib port for java that supported the ZipIt type 
> files.
>
>
> Mike Hall        mikehall at spacestar dot net
> http://www.spacestar.net/users/mikehall
> http://sourceforge.net/projects/macnative
>
>
>
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