This is a more or less straight port of the xpkSubLibrary xpkGZIP.
The original (68k) including the source code can be found at Aminet
(util/pack/xpkGZIP.lha).

I did one quick speed comparison using "Diavolo Backup 2000" under OS4s 68k emu
(no jit!) backing up my complete WorkBench partition (~80GB):

- xpkFAST (68k)
 Duration:    3:54 Minutes
 Effective speed:  19.95 MB/Minute
 Real speed:    12.42 MB/Minute
 Saved by compression: 38%

- xpkGZIP (68k)
 Duration:    14:11 Minutes
 Effective speed:  5.485 MB/Minute
 Real speed:    2.941 MB/Minute
 Saved by compression: 47%

- xpkGZIP (OS4 ppc - this one)
 Duration:    1:36 Minutes
 Effective speed:  48.62 MB/Minute
 Real speed:    26.07 MB/Minute
 Saved by compression: 47%

Quite a "little bit" faster if you ask me ;-)

As this is my first library (port) ever - forgive me if it may not completely
work as expected.

Regards,
Michael Merkel