This is a quick and slightly dirty fix to make the code
conform to the latest file format specification. Without
this patch, it's possible to make corrupt files by
specifying start offset that is not a multiple of the
filter's alignment. Custom start offset is almost never
used, so this was only a minor bug.
The xz command line tool doesn't validate the start offset,
so one will get a bit unclear error message if trying to use
an invalid start offset.
like "un", "cat", and "lz" when determining if
xz is run as unxz, xzcat, lzma, unlzma, or lzcat.
This is to ensure that if xz is renamed (e.g. via
--program-transform-name), it doesn't so easily
work in wrong mode.
It was ignored for compatibility with xz, but now that
--decompress --stdout --force copies unrecognized files
as is to stdout, simply ignoring --force in xzdec would
be wrong. xzdec will not support copying unrecognized
data as is to stdout, so it cannot support --force.
use AC_PROG_SED. We don't do anything fancy with sed,
so this should work OK. libtool 2.2 sets SED but 1.5
doesn't, so $(SED) happened to work when using libtool 2.2.
the latest versions found from gzip CVS repository.
configure will try to find a POSIX shell to be used by
the scripts. This should ease portability on systems
which have pre-POSIX /bin/sh.
xzgrep and xzdiff support .xz, .lzma, .gz, and .bz2 files.
xzmore and xzless support only .xz and .lzma files.
The name of the xz executable used in these scripts is
now correct even if --program-transform-name has been used.
files as is to standard output.
This feature is needed to be more compatible with gzip's
behavior. This was more complicated to implement than it
sounds, because the way liblzma is able to return errors with
files of only a few bytes in size. xz now has its own file
type detection code and no longer uses lzma_auto_decoder().
Don't use libtool convenience libraries to avoid recently
discovered long-standing subtle but somewhat severe bugs
in libtool (at least 1.5.22 and 2.2.6 are affected). It
was found when porting XZ Utils to Windows
<http://lists.gnu.org/archive/html/libtool/2009-06/msg00070.html>
but the problem is significant also e.g. on GNU/Linux.
Unless --disable-shared is passed to configure, static
library built from a set of convenience libraries will
contain PIC objects. That is, while libtool builds non-PIC
objects too, only PIC objects will be used from the
convenience libraries. On 32-bit x86 (tested on mobile XP2400+),
using PIC instead of non-PIC makes the decompressor 10 % slower
with the default CFLAGS.
So while xz was linked against static liblzma by default,
it got the slower PIC objects unless --disable-shared was
used. I tend develop and benchmark with --disable-shared
due to faster build time, so I hadn't noticed the problem
in benchmarks earlier.
This commit also adds support for building Windows resources
into liblzma and executables.
--format=lzma. This means that xz emulating lzma
doesn't decompress .xz files, while before this
commit it did. The new way is slightly simpler in
code and especially in upcoming documentation.
Lasse Collin