Compression algorithms

[Wayne Diamond]

A search across all forums for "compress" yielded many results but none that were fruitful / supported all 256 characters / relatively easy to implement / decompressed to exact string with absolutely no lossiness !
Does anyone have any compression algorithms hidden away in their pockets?



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[Gregery D Engle]

I remember running accross some VB code for Huffman Compression
Scheme. You can search for it at www.planetsourcecode.com




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-Greg

[Wayne Diamond]

Gregery, Ive tried most of the planetsourcecode ones - I was unable to convert many of them to PB as I've only owned PB for three days! Still getting used to it - I got stumped when the best-looking Huffman compression algorithm used a Collection
There does seem to be some excellent compression examples available there (or at least theyve been rated Excellent , but I guess i'll have to read more of my PB book before I can convert them. I better get back to work Many thanks anyway!



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[Don Dickinson]

Search this web bbs for lz or compression and you should find source to PB compression routines that i posted some time ago.
Best Regards,
Don

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[Don Dickinson]

Also, checkout zlib - it's a free compression dll. James Fuller (i think) has posted headers for the zlib library either here or on his site. Do a search for zlib and you'll probably find the info.
Best Regards,
Don

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[Wayne Diamond]

Don,
Somehow your LZ77 example escaped my search, but I just tried it and I love it! It's a superb implementation which is perfect for my purpose, I cannot thank you enough kind sir!




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[Don Dickinson]

I should note that if you're compressing large files (2mb+) the compression algorithm is very slow. Decompression is still fast, however. I usually use zlib for the big stuff as it is very fast.
Best Regards,
Don

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[Wayne Diamond]

Im using it to let my customers compress the scripts that they write for my program. Most scripts are under 5kb, although I had one that was 31kb - down to 8kb after compression. At 30kb, compression took approx half a second, and decompression seemed instant. Perfect for what i want to do! Cheers


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[Edwin Knoppert]

You can build cab files too.

See my site.


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[email protected]

[Michael Burns]

I tossed my Hoffman compression routines and purchased Big Speed.
It was mentioned on another thread, is cheap, and has its routines
set up so creating a zip achive is easy yet very flexable. Considerably faster than WinZip.
http://www.bigspeedsoft.com/bszipdll/bszipdll.html

Other places to look for code are

All BASIC Code Archives (Definitely has some compression routines) http://www.basicguru.com/abc/

VBNet http://www.mvps.org/vbnet/

Microsoft Most Valuable Professional (MVP) http://www.mvps.org/

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Michael Burns
http:\\www.revise.com

[Jim Seekamp]

I wrote a compression program a while back using the same backtracking method as pkzip. Email me for the source code if you want it.


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Jim Seekamp

[Steve Hutchesson]

Jim,

I was about to take you up on the offer of your compression
source but I could not find your email address. It would be
most appreciated if you would point a copy over my way.

[email protected]

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[Gajanan Raje]

Jim,

I will appreciate if you could send me a copy of the compression
code too.

Thanks in advance.

[email protected]

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[James GrahamEagle]

Jim, Me too.

Thanks
Jim
[email protected]

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[Errol Cheverie]

Jim
I would also appreciate if you could send me a copy.

[email protected]

Regards Errol

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