Zip-files

**Doomulation** · April 7th, 2002, 02:51

I was wondering about zip-files...
Having examined them closely, I came up with the following:

Zip-files have an ending-header, a central header and a local header.

The problem I got, is that I don't know where the actual file data is. I'd need this, but I don't have an offset. Anyone has an idea how to do or where the offset is?

**Jsr** · April 7th, 2002, 03:22

Shouldn't it be easier to look at some dokuments or something?

**Glurak** · April 7th, 2002, 03:27

http://www.wotsit.org/

**Doomulation** · April 7th, 2002, 03:34

Thanks! This'll help big time!

**Mayco** · April 7th, 2002, 18:45

that's what i call a usefull site

**Doomulation** · April 8th, 2002, 16:19

I think I understand how the zip-files works now. But still, I can't get the info I want. It complains that everytime I feed the decompress-function of the zlib that the dat is incorrect (return error -3).
I've tried to increase and decrease the position where to begin read from, but it still doesn't work.
The number of bytes I read is equal to which the local header says the compressed size is.

Any idea what's wrong here?

**The Khan Artist** · April 9th, 2002, 00:30

What are you trying to do? Extract one file from a zip with multiple files?

**Doomulation** · April 9th, 2002, 18:09

Originally posted by The Khan Artist
What are you trying to do? Extract one file from a zip with multiple files?

Nah, I just want the rom-header of zipped roms.

**Doomulation** · April 10th, 2002, 12:28

Hmmm, so I guess no one knows what's wrong...

**Hacktarux** · April 10th, 2002, 17:07

Maybe if you use the unzip.c and unzip.h files used for example in pj64 and 1964 you can get the infos you need (i don't know exactly what these files do).

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