Re: Possibility of "64K only" filecracks?

[Egan Ford <datajerk@gmail.com>]

On Jan 2, 11:05 am, Steve Nickolas
<lyricalnan...@usotsuki.hoshinet.org> wrote:
> On Mon, 2 Jan 2012, BLuRry wrote:
> > Donkey Kong has a lot of empty space and repeating patterns -- I'm
> > sure that those images could be compressed down a lot smaller don't
> > you think?  I'm more than happy to donate the compression/
> > decompression of Apple Game Server 3 for the cause.  The decompressor
> > was written to decompress a stream of incoming data from a serial
> > port, but I'm sure that could be very easily translated to something
> > else.  The compression was written in Java -- and there are conversion
> > routines to read images from gif/png so you could use screen grabs if
> > you don't feel like extracting the images directly.  It shouldn't
> > munge the images with dithering if you use a close-enough palette (I
> > based the conversion palette off of a YIQ color mapping, so AppleWin
> > screen grabs that are 560x192 should come back 1:1.)
>
> > -B
>
> Hm.  I *got* a compressor but I only know how to use it for SFX.
>
> http://hem.bredband.net/magli143/exo/
>
> But if it's as I think, maybe another means can be utilized, something
> like an RLE or block compression, that's simple enough to implement on
> 6502?
>
> -uso.

Steve, I've been using this for my projects:

* Piotr Fusik (http://atariarea.krap.pl/x-asm/inflate.html, inflate
6502 code).
* Rich Geldreich (http://code.google.com/p/miniz/, deflate C code).

Fusik's inflate code is just under 512 bytes.  ~768 bytes are needed
as a scratch area and 10 page zero bytes for internal vars.  The code
decompresses only.

Geldreich's C code is what I use to compress the data on my Mac.  I
get the same level of compression as gzip/zip.

Fusik's code is written in his own ATARI assembler.  I ported it to
CA65 if you are interested.  It is easy to use as is checking for
errors.