Re: A92: Zip program for Ti-92
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Re: A92: Zip program for Ti-92
> I'm just writing one, which uses a combined Lempel-Ziv - Huffman algorithm.
It
> will work in this way, that you could create an archive at your PC, and send
it to
> your TI-92. The unpacker at the TI-92 will work like FBrowser, and will
regard
> archives as directories. To run a program, it will be uncompressed to a
temporary
> memory block, and executed by the core. If you have some infos about Huffman
or
> Lempel-Ziv or any other suggestions, mail me! (I haven't any texts about
Lempel
> Ziv or Huffman, so I had to develope my own algorithms)
>
> David Kühling
The problem I found in creating a compressor w/i the calculator was two
fold: the memory needed for decompression, and the fact that small data sets do
not compress well with LZ77, LZ78 OR LZW. Huffman is good, but requires a lot
of useless overhead for the bitstrings. I was examining a project which would
compress and decompress programs using a huffman tree but arithmatic encoding,
also the data would be compressed on top of the existing file, thus not
requiring any additional memory. Decoding would require some extra room
though.
I recommend a book called 'The Data Compression Bood, 2nd Ed.'. Its very good.
I have not examined the run-length encoders (pplib and skittleslib both have
one). I doubt they work as well as Huffman or LZ on machine code though.
--Bryan
bcturner@eos.ncsu.edu
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