DiskDoubler self-extracting archives

[ryandesign]

A common source of pain in getting started with a Macintosh emulator is that you need system software, but old system software was distributed in a self-extracting DiskDoubler archive, and you need to already have the system software installed to be able to open the self-extracting archive.

Could you add support for DiskDoubler self-extracting archives to this library and thus to The Unarchiver and unar?

Sample files are available in this archive of download.info.apple.com, for example SSW_6.0.8-800k_Disk1of4.sea.bin.

% unar SSW_6.0.8-800k_Disk1of4.sea.bin
SSW_6.0.8-800k_Disk1of4.sea.bin: DiskDoubler in MacBinary
  SSW 6.0.8-800k Disk1of4.sea  (838484 B)... OK.
  SSW 6.0.8-800k Disk1of4.sea  (359 B, rsrc)... OK.
Successfully extracted to "SSW 6.0.8-800k Disk1of4.sea".

% unar SSW\ 6.0.8-800k\ Disk1of4.sea
SSW 6.0.8-800k Disk1of4.sea: Couldn't recognize the archive format.

SSW 6.0.8-800k Disk1of4.sea decompresses just fine if I launch it in System 7 running in Mini vMac.

[kradenkov]

Related issue: jsdf/theunarchiver#149

[ryandesign]

You know, I just noticed, it did decompress it, it just didn't name it correctly:

% file SSW\ 6.0.8-800k\ Disk1of4.sea 
SSW 6.0.8-800k Disk1of4.sea: Apple DiskCopy 4.2 image System Tools, 819200 bytes, 0x4b00 tag size, GCR CLV dsdd (800k), 0x22 format