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Forums > C64 Coding > Depacking files from Memory
2019-02-16 20:55
Case

Registered: Aug 2002
Posts: 85
Depacking files from Memory

Hi, i am doing some coding and have hit a wall. I need to pack and then depack 3 pictures from memory depending on a keypress.

Can anyone help me with one ?
 
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2019-02-17 09:57
Erol

Registered: Jul 2003
Posts: 5
I can only speak from my experience.

While making Rewind (Rewind) I have extensively tested Exomizer and ByteBoozer 2.

Everything in this demo is depacked from memory and you can see the amount of content that was managed to pack in under 202 blocks.

BB2 won because depacking was faster than Exomizer and it was important for the demo pace.

So it all depends on your preferences. You need to experiment a little.
2019-02-17 10:16
Krill

Registered: Apr 2002
Posts: 1159
Yes, it very often pays off not to go for the best compression around at the cost of speed.
The only exception would be cracks which get bonus points for being the smallest version around, no matter if there's still space in memory/on the disk/image or not. :)

Exomizer being the reference for best general-purpose compression ratios on C-64, note that the graph I linked is timestamped at April 2017 at the time of writing this, which was before Exomizer 3. Exo 3 is quite a bit faster than Exo 2, yet still in the same slow camp.
2019-02-17 15:53
Case

Registered: Aug 2002
Posts: 85
Hi, I should have been have given more information but it was late and i was tired.

Basically i have 3 standard bitmaps that i want to depack from memory and display one after each other on a loop.

Normally the way to do this would be to have one in each back and just flip between them, however i have some music sitting at $8000 which does not help.

I would also likt to do the depack from memory route so i can increase the number of images later on if needed.

I have tried to use ByteBoozer 2.0, but was unable to get it to depack (proberly due to my poor coding skills). If anyone has a working .exe of the packer and the depacker in kickass format i would be very grateful.
2019-02-17 18:10
Krill

Registered: Apr 2002
Posts: 1159
Quoting Case
i have 3 standard bitmaps [...] i have some music sitting at $8000
So that's 3*10 KB for the pictures and 4-8ish KB for the tune, in a 64 KB system.

Are you sure you need to compress the pictures?
2019-02-17 18:17
Case

Registered: Aug 2002
Posts: 85
Quote: Quoting Case
i have 3 standard bitmaps [...] i have some music sitting at $8000
So that's 3*10 KB for the pictures and 4-8ish KB for the tune, in a 64 KB system.

Are you sure you need to compress the pictures?


not sure, my coding skills were never that great and i was trying to get a little better doing it this way. Would also like to adapt the depack from memory and maybe create another 'heartbeat' release.
2019-02-18 09:00
Luca

Registered: Apr 2002
Posts: 146
I second Krill. I've used Exomizer on Plus/4 in order to depack on the fly both the bitmaps in my demopart included into Crackers' Demo 5 coopdemo: a remarkable packing ratio and easy to manage in general. If I'd been capable to use it, believe me, anybody can ;)
2019-02-18 10:57
Krill

Registered: Apr 2002
Posts: 1159
Quoting Case
If anyone has a working .exe of the packer and the depacker in kickass format i would be very grateful.
Really, try to use the material that's there. If you have no working .exe, build it from source.

Likewise for the C-64 depacking part. It's a library, and as such should be assembled with the tools intended by the author. You can then easily include the binary in your project and use whatever assembler/tools you like. Translating stuff from one assembly syntax to another is a useless exercise most of the time and likely to introduce bugs.
2019-02-20 13:29
mhindsbo

Registered: Dec 2014
Posts: 40
I have experimented a little with the new Exomizer. I find it quite versatile and easy to use.

It is very easy to crunch binary and prg files into a format that can be unpacked from memory.

I converted the decruncher to C64 Studio format if that is helpful to anyone.

BTW does anyone know what flag or similar you need to crunch with to use EXTRA_TABLE_ENTRY_FOR_LENGTH_THREE option? FOr some reason I couldn't find that in the documentation.
2019-02-20 13:36
cadaver

Registered: Feb 2002
Posts: 1106
Check exo30info.txt in the newest version, and the documentation of the -P flag (near the beginning)
2019-02-20 14:02
Krill

Registered: Apr 2002
Posts: 1159
For what it's worth (cue shameless plug): Krill's Loader, Repository Version 166 comes with a memory decompression call and supports various crunchers:
DECOMPRESSOR = DECOMPRESSORS::TINYCRUNCH; available are NONE, BITNAX (recommended for demos), BYTEBOOZER2, DOYNAX_LZ, EXOMIZER, LEVELCRUSH, NUCRUNCH, PUCRUNCH, SUBSIZER, TINYCRUNCH (recommended for demos)
If loading isn't actually required, the code can at least serve as a how-to.
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