lzma_filters_free() sets the options to NULL and ids to
LZMA_VLI_UNKNOWN so there is no need to do it by caller;
the filter arrays will always be left in a safe state.
Also use memcpy() instead of a loop to copy a filter chain
when it is known to be safe to copy LZMA_FILTERS_MAX + 1
(even if the elements past the terminator might be uninitialized).
The bug was in the single-threaded .xz Stream encoder
in the code that is used for both re-initialization and for
lzma_filters_update(). To trigger it, an application had
to either re-initialize an existing encoder instance with
lzma_stream_encoder() or use lzma_filters_update(), and
then one of the 1-4 tiny allocations in lzma_filters_copy()
(called from stream_encoder_update()) must fail. An error
was correctly reported but the encoder state was corrupted.
This is related to the recent fix in
f8ee61e74e which is good but
it wasn't enough to fix the main problem in stream_encoder.c.
Only one definition was visible in a translation unit.
It avoided a few casts and temp variables but seems that
this hack doesn't work with link-time optimizations in compilers
as it's not C99/C11 compliant.
Fixes:
http://www.mail-archive.com/xz-devel@tukaani.org/msg00279.html
There is a tiny risk of causing breakage: If an application
assigns lzma_stream.allocator to a non-const pointer, such
code won't compile anymore. I don't know why anyone would do
such a thing though, so in practice this shouldn't cause trouble.
Thanks to Jan Kratochvil for the patch.
It leaks old filter options structures (hundred bytes or so)
every time the lzma_stream is reinitialized. With the xz tool,
this happens when compressing multiple files.
This breaks API and ABI but most apps are not affected
since most apps don't use this part of the API. You will
get a compile error if you are using anything that got
broken.
Summary of changes:
- Ability to store Stream Flags, which are needed
for random-access reading in multi-Stream files.
- Separate function to set size of Stream Padding.
- Iterator structure makes it possible to read the same
lzma_index from multiple threads at the same time.
- A lot faster code to locate Blocks.
- Removed lzma_index_equal() without adding anything
to replace it. I don't know what it should do exactly
with the new features and what actually needs this
function in the first place other than test_index.c,
which now has its own code to compare lzma_indexes.
Originally the idea was that using LZMA_FULL_FLUSH
with Stream encoder would read the filter chain
from the same array that was used to intialize the
Stream encoder. Since most apps wouldn't use
LZMA_FULL_FLUSH, most apps wouldn't need to keep
the filter chain available after initializing the
Stream encoder. However, due to my mistake, it
actually required keeping the array always available.
Since setting the new filter chain via the array
used at initialization time is not a nice way to do
it for a couple of reasons, this commit ditches it
and introduces lzma_filters_update(). This new function
replaces also the "persistent" flag used by LZMA2
(and to-be-designed Subblock filter), which was also
an ugly thing to do.
Thanks to Alexey Tourbin for reminding me about the problem
that Stream encoder used to require keeping the filter
chain allocated.
liblzma tries to avoid useless free()/malloc() pairs in
initialization when multiple files are handled using the
same lzma_stream. This didn't work with filter chains
due to comparison of wrong pointers in lzma_next_coder_init(),
making liblzma think that no memory reallocation is needed
even when it actually is.
Easy way to trigger this bug is to decompress two files with
a single xz command. The first file should have e.g. x86+LZMA2
as the filter chain, and the second file just LZMA2.
- Updated to the latest, probably final file format version.
- Command line tool reworked to not use threads anymore.
Threading will probably go into liblzma anyway.
- Memory usage limit is now about 30 % for uncompression
and about 90 % for compression.
- Progress indicator with --verbose
- Simplified --help and full --long-help
- Upgraded to the last LGPLv2.1+ getopt_long from gnulib.
- Some bug fixes
broken. API has changed a lot and it will still change a
little more here and there. The command line tool doesn't
have all the required changes to reflect the API changes, so
it's easy to get "internal error" or trigger assertions.
specification. Simplify things by removing most of the
support for known uncompressed size in most places.
There are some miscellaneous changes here and there too.
The API of liblzma has got many changes and still some
more will be done soon. While most of the code has been
updated, some things are not fixed (the command line tool
will choke with invalid filter chain, if nothing else).
Subblock filter is somewhat broken for now. It will be
updated once the encoded format of the Subblock filter
has been decided.
Lasse Collin