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  • Compression algorithms

    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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  • #2
    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
    -Greg
    [email protected]
    MCP,MCSA,MCSE,MCSD

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    • #3
      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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      • #4
        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
        www.greatwebdivide.com

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        • #5
          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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          Don Dickinson
          www.greatwebdivide.com

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          • #6
            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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            • #7
              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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              Don Dickinson
              www.greatwebdivide.com

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              • #8
                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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                • #9
                  You can build cab files too.

                  See my site.


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                  [email protected]
                  hellobasic

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                  • #10
                    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
                    Michael Burns

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                    • #11
                      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
                      Jim Seekamp

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                      • #12
                        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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                        hutch at movsd dot com
                        The MASM Forum

                        www.masm32.com

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                        • #13
                          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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                          Gajanan Raje

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                          • #14
                            Jim, Me too.

                            Thanks
                            Jim
                            [email protected]

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                            • #15
                              Jim
                              I would also appreciate if you could send me a copy.

                              [email protected]

                              Regards Errol

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