Re: [svenjoac@gmx.de: Adding --lzma option to make-dist]

Re: [svenjoac@gmx.de: Adding --lzma option to make-dist]

[Karl Berry]

rms forwarded me Sven's message about lzma.  With apologies for
repeating things people may already know:

    It seems that the lzma format would be a very good candidate for
    distribution tarballs, 

Yes indeed.  In fact, Jim Meyering has already made patches to automake
to support it; he plans to distribute the next coreutils as .gz and
.lzma.  tar will support it at some point, too.  If GNU packages start
using it, I'm sure it will become rather widespread rather quickly :).

    if only it were more widespread; information and
    downloads are available at http://www.7-zip.org/sdk.html.

That is indeed the original web site, but the software distributed there
(and in the p7zip project, which is the 7-zip.org code ported to POSIX)
contains nonfree code related to the rar format (nothing about lzma
itself).  The authors were not interested in removing the rar code.

Fortunately, another hacker has put together a 100% free distribution,
with the standard autotools && make infrastructure, and a cmdline
interface similar to gzip and bzip2:
http://tukaani.org/lzma/

The only caveat is that the file format will change once more; however,
newer versions will be able to read older lzma archives, so as long as
we stick to the 4.32.x series for now, it should be fine to use.

Karl

Re: [svenjoac@gmx.de: Adding --lzma option to make-dist]

[Dan Nicolaescu]

karl@freefriends.org (Karl Berry) writes:

  > Fortunately, another hacker has put together a 100% free distribution,
  > with the standard autotools && make infrastructure, and a cmdline
  > interface similar to gzip and bzip2:
  > http://tukaani.org/lzma/
  > 
  > The only caveat is that the file format will change once more; however,
  > newer versions will be able to read older lzma archives, so as long as
  > we stick to the 4.32.x series for now, it should be fine to use.

Do you know if the format change will add a proper magic number? Right
now the "file" command cannot recognize lzma files. I talked to the
"file" maintainer and he looked at it and said that the format is not
suitable for "file"... If you know the people involved, please forward
this concern.

Thanks

        --dan

Re: [svenjoac@gmx.de: Adding --lzma option to make-dist]

[James Cloos]

>>>>> "Dan" == Dan Nicolaescu <dann@ics.uci.edu> writes:

Dan> Do you know if the format change will add a proper magic number?

,----< from http://tukaani.org/lzma/ >
| * New header format: adds magic bytes, filter support and CRC32
`----

And the download page says that the current version of the legacy code
base (4.32.4) has support for detecting the new header.  From that src
there is this:

,----[ lzma-4.32.4/extra/magic/lzma.magic ]
| 0x00    ustring         \xFFLZMA\x00    lzma compressed data,
| >0x06   ubyte&0x10      0x00            single-block stream
| >0x06   ubyte&0x10      0x10            multi-block stream
`----

So it looks like they have it covered.

(For those looking at their git repos, I only find the magic file in
the legacy repo <git://ctrl.tukaani.org/lzma-utils-legacy.git> and not
in the new codebase <git://ctrl.tukaani.org/lzma-utils.git>.)

-JimC
-- 
James Cloos <cloos@jhcloos.com>         OpenPGP: 1024D/ED7DAEA6