pre compress::zlib:

the code took:17 wallclock secs (11.76 usr  2.52 sys +  0.25 cusr  0.25 csys = 14.78 CPU)

with compress:zlib:

the code took:15 wallclock secs ( 9.71 usr  2.60 sys +  0.02 cusr  0.06 csys = 12.39 CPU)

Not much of a difference, but for more files, I found the
saving in time up to 10 seconds.

Thanks once again!

Regards,
	Stacy.