xzdec might build with VS2013 but it hasn't been tested.
It was never supported before and VS2013 is old anyway
so for simplicity only liblzma is supported with VS2013.
Building the command line tools xz and xzdec with the combination
of CMake + Visual Studio 2015/2017/2019/2022 works now.
VS2013 update 2 should still be able to build liblzma.
VS2013 cannot build the xz command line tool because xz
needs snprintf() that roughly conforms to C99.
VS2013 is old and no extra code will be added to support it.
Thanks to Kelvin Lee and Jia Tan for testing.
There are several new policies. CMP0149 may affect the Windows SDK
version that CMake will choose by default. The new behavior is more
predictable, always choosing the latest SDK version by default.
The other new policies shouldn't affect this package.
If CMake was configured more than once, HAVE_CLOCK_GETTIME and
HAVE_CLOCK_MONOTONIC would not be set as compile definitions. The check
for librt being needed to provide HAVE_CLOCK_GETTIME was also
simplified.
The CMake build will try to create broken symlinks on Unix and Unix-like
platforms. Cygwin and MSYS2 are Unix-like, but may not be able to create
broken symlinks. The value of the CYGWIN or MSYS environment variables
determine if broken symlinks are valid.
The default for MSYS2 does not allow for broken symlinks, so the CMake
build has been broken for MSYS2 since commit
80a1a8bb83.
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.
The thread method is now configurable for the CMake build. It matches
the Autotools build by allowing ON (pick the best threading method),
OFF (no threading), posix, win95, and vista. If both Windows and
posix threading are both available, then ON will choose Windows
threading. Windows threading will also not use:
target_link_libraries(liblzma Threads::Threads)
since on systems like MinGW-w64 it would link the posix threads
without purpose.
This allows users to change the features they build either in
CMakeCache.txt or by using a CMake GUI. The sources built for
liblzma are affected by this too, so only the necessary files
will be compiled.
Now, the LZMA_VERSION_MAJOR, LZMA_VERSION_MINOR, and LZMA_VERSION_PATCH
macros do not need to be on consecutive lines in version.h. They can be
separated by more whitespace, comments, or even other content, as long
as they appear in the proper order (major, minor, patch).
At least on some systems, GNU windres needs --use-temp-file
in addition to the \x20 hack to avoid spaces in the command line
argument. Hovever, that \x20 syntax is broken with llvm-windres
version 15.0.0 (results in "XZx20Utils") but luckily it works
with a regular space. Thus it is best to limit the workarounds
to GNU toolchain on Windows.
The command line tools cannot be built with MSVC for now but
they can be built with MinGW-w64.
Thanks to Iouri Kharon for the bug report and the original patch.
Previously, if threading was enabled HAVE_DECL_CLOCK_MONOTONIC would always
be set to 0 or 1. However, this macro was needed in xz so if xz was not
built with threading and HAVE_DECL_CLOCK_MONOTONIC was not defined but
HAVE_CLOCK_GETTIME was, it caused a warning during build. Now,
HAVE_DECL_CLOCK_MONOTONIC has been renamed to HAVE_CLOCK_MONOTONIC and
will only be set if it is 1.
It not only makes no sense to put symbol versions into a static library
but it can also cause breakage.
By default Libtool #defines PIC if building a shared library and
doesn't define it for static libraries. This is documented in the
Libtool manual. It can be overriden using --with-pic or --without-pic.
configure.ac detects if --with-pic or --without-pic is used and then
gives an error if neither --disable-shared nor --disable-static was
used at the same time. Thus, in normal situations it works to build
both shared and static library at the same time on GNU/Linux,
only --with-pic or --without-pic requires that only one type of
library is built.
Thanks to John Paul Adrian Glaubitz from Debian for reporting
the problem that occurred on ia64:
https://www.mail-archive.com/xz-devel@tukaani.org/msg00610.html
It also works on E2K as it supports these intrinsics.
On x86-64 runtime detection is used so the code keeps working on
older processors too. A CLMUL-only build can be done by using
-msse4.1 -mpclmul in CFLAGS and this will reduce the library
size since the generic implementation and its 8 KiB lookup table
will be omitted.
On 32-bit x86 this isn't used by default for now because by default
on 32-bit x86 the separate assembly file crc64_x86.S is used.
If --disable-assembler is used then this new CLMUL code is used
the same way as on 64-bit x86. However, a CLMUL-only build
(-msse4.1 -mpclmul) won't omit the 8 KiB lookup table on
32-bit x86 due to a currently-missing check for disabled
assembler usage.
The configure.ac check should be such that the code won't be
built if something in the toolchain doesn't support it but
--disable-clmul-crc option can be used to unconditionally
disable this feature.
CLMUL speeds up decompression of files that have compressed very
well (assuming CRC64 is used as a check type). It is know that
the CLMUL code is significantly slower than the generic code for
tiny inputs (especially 1-8 bytes but up to 16 bytes). If that
is a real-world problem then there is already a commented-out
variant that uses the generic version for small inputs.
Thanks to Ilya Kurdyukov for the original patch which was
derived from a white paper from Intel [1] (published in 2009)
and public domain code from [2] (released in 2016).
[1] https://www.intel.com/content/dam/www/public/us/en/documents/white-papers/fast-crc-computation-generic-polynomials-pclmulqdq-paper.pdf
[2] https://github.com/rawrunprotected/crc
This uses it for CRC table initializations when using --disable-small.
It avoids mythread_once() overhead. It also means that then
--disable-small --disable-threads is thread-safe if this attribute
is supported.
That is, the Filter ID will be changed once the design is final.
The current version will be removed. So files created with the
tempoary Filter ID won't be supported in the future.
Jia Tan
Lasse Collin
Dimitri Papadopoulos Orfanos
Hans Jansen
Benjamin Buch