archivers/rzip 2.1_2 FreeBSD

rzip is a compression program, similar in functionality to gzip or bzip2, but able to take advantage from long distance redundancies in files, which can sometimes allow rzip to produce much better compression ratios than other programs.

The principal advantage of rzip is that it has an effective history buffer of 900 Mbyte. This means it can find matching pieces of the input file over huge distances compared to other commonly used compression programs. The gzip program by comparison uses a history buffer of 32 kbyte and bzip2 uses a history buffer of 900 kbyte. The second advantage of rzip over bzip2 is that it is usually faster. This may seem surprising at first given that rzip uses the bzip2 library as a backend (for handling the short-range compression), but it makes sense when you realise that rzip has usually reduced the data a fair bit before handing it to bzip2, so bzip2 has to do less work.