Mikołaj Izdebski wrote: > Do you consider alternative bzip2 implementations available in Debian > (lbzip2, pbzip2, p7zip-full, libcommons-compress-java) as "commonly > available implementations"? They all produce different compressed > files for the same input file. Moreover, lbzip2-0.23 from stable > produces different files than lbzip2-2.1 from unstable.
I have not seen files produced by these yet afaik, but it's sure nice to have a list to try when someone comes with a weird file; I did not know about some of those! Even bzip2 changed its output after 0.9.5d -- I have a program that uses the compressor from the old version since some files needed it. > I believe that pristine-tar generates "binary diffs" for gzip files it > fails to reproduce, but doesn't do the same for bzip2 files. Maybe > implementing such feature for bzip2 files is the solution? I'll add it if I see a bz2 file that can nearly exactly be reproduced and only needs the delta to get the rest of the way. Haven't yet. > My point was that block size isn't the only factor the resulting file > depends on. There is also a "work factor", as described in bzip2 > documentation. Even the same version of bzip2, with the same block > size given, for the same input can produce different outputs, given > that work factors are different. A proof of concept is available in > lbzip2 git repo: I have yet to see a bz2 file in the wild that uses a nonstandard block size, so pristine-bz2 doesn't bother to try nonstandard block sizes by default yet. Since bzip2 --exponential is not documented, I will worry about it when I find a file using it in the wild. -- see shy jo
signature.asc
Description: Digital signature
