Re: LZW Compression algorithm


"Z.K." <nospam@xxxxxxxxxx> wrote in message
news:rPObg.2639$p13.1854@xxxxxxxxxxx
I am trying to create a simple compression algorithm using the LZW system
based on the 128 ascii character set and I can find a lot of information on
the general description of it, but how exactly does the dictionary that is
used work. Is it just stored in an array or do you need to write it to a
file so that it can be used the next time you need to decompress a file. I
would think it would need to be stored in a file and then read into an
array since if you compressed the file and then shut down the program,
would you not lose everything in the dictionary and then not be able to
decompress the file? Any help would be appreciated.


the dictionary is created as a side effect of the algorithm, thus if
implemented sanely, one does not need to store the dictionary, as it is
recreated again during decompression...


note that if you are looking for a simple compressor that does fairly well,
it may be more useful to look into lz77 or markov prediction or similar.

Thanks,

Z.K.


.

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