Philip Warner <pjw(at)rhyme(dot)com(dot)au> writes:
> FWIW, I think Unisys patented the LZW algorithm only.
More specifically, Unisys patented Terry Welch's variant of the LZ78
class of algorithms. Jan's code falls in the substantially different
LZ77 class. There could be problematic patents out there, but Unisys'
is certainly not one.
(If you don't know the difference between LZ77 and LZ78, see the
comp.compression FAQ ... but don't raise alarms about compression
patents if you don't know even that much about the field, eh?)
regards, tom lane