freebsd-skq/contrib/xz/TODO
Martin Matuska 81ad83880d Import of liblzma, xz, xzdec, lzmainfo from vendor branch
Add support for xz and lzma to lesspipe.sh (xzless, lzless)
Bump __FreeBSD_version

Approved by:	delphij (mentor)
MFC after:	2 weeks
2010-05-10 06:59:50 +00:00

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XZ Utils To-Do List
===================
Known bugs
----------
The test suite is too incomplete.
If the memory usage limit is less than about 13 MiB, xz is unable to
automatically scale down the compression settings enough even though
it would be possible by switching from BT2/BT3/BT4 match finder to
HC3/HC4.
The code to detect number of CPU cores doesn't count hyperthreading
as multiple cores. In context of xz, it probably should.
Hyperthreading is good at least with p7zip.
XZ Utils compress some files significantly worse than LZMA Utils.
This is due to faster compression presets used by XZ Utils, and
can be worked around by using "xz --extreme". However, the presets
need some tweaking and maybe this issue can be minimized without
making the typical case too much slower.
xz doesn't quote unprintable characters when it displays file names
given on the command line.
tuklib_exit() doesn't block signals => EINTR is possible.
Missing features
----------------
xz doesn't support copying extended attributes, access control
lists etc. from source to target file.
Multithreaded compression
Multithreaded decompression
Buffer-to-buffer coding could use less RAM (especially when
decompressing LZMA1 or LZMA2).
I/O library is not implemented. It will possibly be named libzzf.
lzma_strerror() to convert lzma_ret to human readable form?
This is tricky, because the same error codes are used with
slightly different meanings.
Documentation
-------------
Some tutorial is needed for liblzma. I have planned to write some
extremely well commented example programs, which would work as
a tutorial. I suppose the Doxygen tags are quite OK as a quick
reference once one is familiar with the liblzma API.
Document the LZMA1 and LZMA2 algorithms.