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gwerz / theunarchiver

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Improve DiskDoubler support #149

Open GoogleCodeExporter opened 9 years ago

GoogleCodeExporter commented 9 years ago 
The version of Unarchiver I just downloaded does not seem to decompress
files compressed by DiskDoubler 3.7.7. It returns a message with "Unknown
data format". if one continues, a blank decompressed file is produced.

I am running Mac OSX 10.5.6. I see that the Preferences includes a check
box for

DiskDoubler Archive extensions dd, DD.

Is there something I am doing wrong or does Unarchiver not decompress
DiskDoubler 3.7.7 files? If so, any suggestions on how to decompress these
files?

MANY thanks,

S.

Original issue reported on code.google.com by orz...@freshpond.org on 25 Mar 2009 at 6:02

GoogleCodeExporter commented 9 years ago 
It appears that DiskDoubler supported multifile archives (one archive 
containing multiple files). I will have to test these.

Original comment by d235...@gmail.com on 30 Sep 2010 at 4:05

GoogleCodeExporter commented 9 years ago 
Yes, they are supported in The Unarchiver too. They basically just wrap several 
regular DiskDoubler files into a single file, with some extra headers for 
filenames and such. If the app creating that has any further options for 
compression methods, it could be interesting checking those out.

Original comment by paracel...@gmail.com on 30 Sep 2010 at 4:11

GoogleCodeExporter commented 9 years ago 
I can't seem to generate any more types of files. Probably need to find 
AutoDoubler 1.x and DiskDoubler 2.x, as well as 3.1 to 3.7.2.

This decompression code works though. Thanks!

Original comment by d235...@gmail.com on 30 Sep 2010 at 9:54

GoogleCodeExporter commented 9 years ago 
Seems like you forgot to add XADXORSumHandle.* to the Xcode project.

Original comment by d235...@gmail.com on 1 Oct 2010 at 2:14

GoogleCodeExporter commented 9 years ago 
Yeah, I was working on the Linux version earlier. It's added now, I forget if I 
pushed it yet though.

Original comment by paracel...@gmail.com on 1 Oct 2010 at 2:56

GoogleCodeExporter commented 9 years ago 
All right, I have some working code for method 2. Method 5 might also work, but 
I obviously haven't been able to test it. All the test cases for method 2 
unpack correctly, though.

(I really don't understand method 2 at all, even though the code is extremely 
simple. It doesn't look like anything I've ever seen before. It's some kind of 
adaptive Huffman-like encoding with first-order contexts, working on individual 
bytes with no LZ encoding at all? Weird.)

Original comment by paracel...@gmail.com on 1 Oct 2010 at 5:46

GoogleCodeExporter commented 9 years ago 
Method 2 seems to be very effective on Mac applications and the like, but very 
ineffective on text. Probably a custom algorithm designed for MC68000-type 
code, and similar data?

As for Method 5, I'm hunting for some versions of DiskDoubler that might 
support it. May take some time though.

Original comment by d235...@gmail.com on 1 Oct 2010 at 5:49

GoogleCodeExporter commented 9 years ago 
Here are some older Disk Doubler files

Original comment by muelle...@gmail.com on 16 Feb 2011 at 5:57

Attachments:

GoogleCodeExporter commented 9 years ago 
Some of those seem to not be compressed at all, but a few of them are 
apparently in some really old DiskDoubler format which I have not seen before. 
Those should come in useful! Thanks!

Original comment by paracel...@gmail.com on 16 Feb 2011 at 6:28