Pure VB zip library?

[DigiRev]

There is a pure VB class to save images as JPEG without any dependencies. I'm hoping something like that exists for zipping/compressing data.

I don't need to read .zip files or extract them, just compress. I'm not sure what algorithm is usually used. LZW? Or something?

I've found a few for RLE, LZW (or whatever it's called), Huffman, etc.

Can anyone recommend a good one to use? I really want something close to the compression ratio of WinZip for text and images. And I don't have VB at this computer so I can't test any of them right now.

I just want to compress some data (sometimes text, sometimes binary image data) before transmitting. And I don't want to use the ZLib or any other DLL. And I don't want to have to save to file first.

[technorobbo]

Check out this PSC article http://www.planet-source-code.com/vb...&lngWId=-1#zip
It's got all the code you need

[DigiRev]

I've seen that and it's only for NT/XP.

[technorobbo]

I wrote a decompress program for a guy using that api and he had Vista. It worked fine. Have you tried it?

[DigiRev]

Yeah Vista uses NT. I mean for older operating systems like Windows 98.

I found a few on there but unfortunately, can't test any of them right now, and was wondering if anyone had one lying around that they use or know of a good one online.

[Siddharth Rout]

How about this... works for win 98... and is FREE

http://www.softlist.net/program/bw_z...-download.html

also check out the section "Unziping file" right at the bottom in the below mentioned link...

http://www.completelyfreesoftware.co...ime_files.html

Edit
Another interesting concept using c#. i am not sure if this will work in W98

http://www.codeproject.com/KB/cs/com...hellapics.aspx

This looks promising as it has been tested for Win 98. Source code at the bottom of that link...
http://home.scarlet.be/~tsc08989/sawzip.htm

[DigiRev]

Thanks, but like I said, I don't want to add any dependencies/use any DLLs (or OCXs)......

[Milk]

Don't know if this will help, it's my interpretation of a Huffman entropy encoder/decoder (possibly quite different from a standard Huffman encoder)

It's best suited for text typically yielding an output of < 60% of the input. It's not suitable for small strings and most images

It might not be that great compression wise but it is pure vb (no API) and it's fairly fast.

I'm sure I've seen a VB version of LZ77 on psc at some point.

What do your images typically look like? Random or like photos or like

Edit: Just remembered something re strings. The main reason why small strings compress badly is the inclusion of the dictionary. A standard dictionary can be used for all strings meaning is does not have to be included.