Re: [Lzip-bug] Tarball indexing and plzip

[Antonio Diaz Diaz]

Hi Dennis,

Dennis Katsonis wrote:
> The difference is when decompressing a single file from near the end of
> the archive.

I expect tarlz to become as fast as pixz in this case as soon as 
parallel extraction is implemented in tarlz, with the advantage that 
tarlz produces standard .lz files while pixz uses a non-standard 
extension to the xz format (trailing data).


> The difficulty would be supporting the different tar formats (ustar,
> xustar, exustar, etc).

I do not plan to support anything but a cleaned-up variant of the pax 
format in tarlz. Here you may see why:
http://www.nongnu.org/lzip/manual/tarlz_manual.html#Amendments-to-pax-format

Note that the tarlz format is mainly ustar. Extended pax headers are 
used only when needed because the length of a filename or link name, or 
the size of a file exceed the limits of the ustar format.


> Perhaps indexing could be abstracted in a particular way, so that
> anyone using the library could use this for their own compressed file
> formats?

Indexing in tarlz is provided by the lzip format itself. It is not 
generalizable to other compressed formats.


Best regards,
Antonio.