The new command line options are meant to be combined with --block-list.
They work as an optional extension to --block-list to specify a custom
filter chain for each block listed. The new options allow the creation
of up to 9 reusable filter chains. For instance:
xz --block-list=1:10MiB,3:5MiB,,2:5MiB,1:0 --filters1=delta--lzma2 \
--filters2=x86--lzma2 --filters3=arm64--lzma2
Will create the following blocks:
1. A block of size 10 MiB with filter chain delta, lzma2.
2. A block of size 5 MiB with filter chain arm64, lzma2.
3. A block of size 5 MiB with filter chain arm64, lzma2.
4. A block of size 5 MiB with filter chain x86, lzma2.
5. A block containing the rest of the file contents with filter chain
delta, lzma2.
This is a little cleaner than the previous implementation of
forget_filter_chain(). It is also more consistent since
lzma_str_to_filters() will always terminate the filter chain so there
is no need to terminate it later in coder_set_compression_settings().
The --filters option uses the new lzma_str_to_filters() function
to convert a string into a full filter chain. Using this option
will reset all previous filters set by --preset, --[filter], or
--filters.
Fixed a bug where test_compress_* would all fail if arm64 or armthumb
filters were enabled for compression but arm was disabled. Since the
grep tests only checked for "define HAVE_ENCODER_ARM", this would match
on HAVE_ENCODER_ARM64 or HAVE_ENCODER_ARMTHUMB.
Now the config.h feature test requires " 1" at the end to prevent the
prefix problem. have_feature() was also updated for this even though
there were known current bugs affecting it. This is just in case future
features have a similar prefix problem.
Commit 78704f36e7 added an empty
initializer {} to prevent a warning. The empty initializer is a GNU
extension and results in a build failure on MSVC. The -wpedantic flag
warns about empty initializers.
Several tests were missing calls to lzma_index_end() to clean up the
lzma_index structs. The memory leaks were discovered by using
-fsanitize=address with GCC.
test_block_header was not properly freeing the filter options between
calls to lzma_block_header_decode(). The memory leaks were discovered by
using -fsanitize=address with GCC.
This change only impacts the compiler warning since it was impossible
for the wait_abs struct in stream_encode_mt() to be used before it was
initialized since mythread_condtime_set() will always be called before
mythread_cond_timedwait().
Since the mythread.h code is different between the POSIX and
Windows versions, this warning was only present on Windows builds.
Thanks to Arthur S for reporting the warning and providing an initial
patch.
In lzma_memcmplen(), the <intrin.h> header file is only included if
_MSC_VER and _M_X64 are both defined but _BitScanForward64() was
previously used if _M_X64 was defined. GCC for MSYS2 defines _M_X64 but
not _MSC_VER so _BitScanForward64() was used without including
<intrin.h>.
Now, lzma_memcmplen() will use __builtin_ctzll() for MSYS2 GCC builds as
expected.
ci_build.sh was updated to accept disabling of __attribute__ ifunc
and CLMUL. This will allow -fsanitize=address to pass because ifunc
is incompatible with -fsanitize=address. The CLMUL implementation has
optimizations that potentially read past the buffer and mask out the
unwanted bytes.
This test will only run on Autotools Linux.
The ifunc method avoids indirection via the function pointer
crc64_func. This works on GNU/Linux and probably on FreeBSD too.
The previous __attribute((__constructor__)) method is kept for
compatibility with ELF platforms which do support ifunc.
The ifunc method has some limitations, for example, building
liblzma with -fsanitize=address will result in segfaults.
The configure option --disable-ifunc must be used for such builds.
Thanks to Hans Jansen for the original patch.
Closes: https://github.com/tukaani-project/xz/pull/53
CMake build system will now verify if __attribute__((__ifunc__())) can be
used in the build system. If so, HAVE_FUNC_ATTRIBUTE_IFUNC will be
defined to 1.
Boost iostream uses `find_package` in quiet mode and then again uses
`find_package` with required. This second call triggers a
`add_library cannot create imported target "ZLIB::ZLIB" because another
target with the same name already exists.`
This can simply be fixed by skipping the alias part on secondary
`find_package` runs.
Reword "options required" to "supported options". The previous may have
suggested that the options listed were all required anytime a filter is
used for encoding or decoding. The reword makes this more clear that
adjusting the options is optional.
The lzma_mt_block_size() was previously just an internal function for
the multithreaded .xz encoder. It is used to provide a recommended Block
size for a given filter chain.
This function is helpful to determine the maximum Block size for the
multithreaded .xz encoder when one wants to change the filters between
blocks. Then, this determined Block size can be provided to
lzma_stream_encoder_mt() in the lzma_mt options parameter when
intializing the coder. This requires one to know all the filter chains
they are using before starting to encode (or at least the filter chain
that will need the largest Block size), but that isn't a bad limitation.
Jia Tan