Replace bzip2

[Artoria2e5]

bzip2 is ancient. It is slow to decompress and does not provide the best compression ratio. Most projects have switched to something else; Fedora's comparison may be useful here. Since this is a new version of FAH, it might finally be time to also change the compression on the tarball.

Some timing and sizing data on fahcore-22-windows-64bit-release-0.0.20. The -T0 in xz enables multithreading; both single-threaded and multi-thread decomp are tested.

$ time bzip2 -dk fahcore-22-windows-64bit-release-0.0.20.tar.bz2
real    0m13.048s
user    0m0.000s
sys     0m0.000s

$ xz -T0 -k -v --x86 --lzma2=preset=6 fahcore-22-windows-64bit-release-0.0.20.tarfahcore-22-windows-64bit-release-0.0.20.tar (1/1)
  100 %       116.5 MiB / 236.3 MiB = 0.493    15 MiB/s       0:15

$ ls -l fah*
-rw-r--r-- 1 arthu arthu 247808000 Sep  1 15:07 fahcore-22-windows-64bit-release-0.0.20.tar
-rw-r--r-- 1 arthu arthu 156444974 Sep  1 15:08 fahcore-22-windows-64bit-release-0.0.20.tar.bz2
-rw-r--r-- 1 arthu arthu 122121176 Sep  1 15:07 fahcore-22-windows-64bit-release-0.0.20.tar.xz

$ rm  fahcore-22-windows-64bit-release-0.0.20.tar

$ time xz -dk fahcore-22-windows-64bit-release-0.0.20.tar.xz
real    0m7.548s
user    0m0.000s
sys     0m0.000s

$ rm  fahcore-22-windows-64bit-release-0.0.20.tar

$ time xz -T0 -dk fahcore-22-windows-64bit-release-0.0.20.tar.xz
real    0m1.418s
user    0m0.000s
sys     0m0.000s

$ zstd fahcore-22-windows-64bit-release-0.0.20.tar
fahcore-22-windows-64bit-release-0.0.20.tar : 59.84%   (   236 MiB =>    141 MiB, fahcore-22-windows-64bit-release-0.0.20.tar.zst)

$ ls -l fahcore-22-windows-64bit-release-0.0.20.tar.zst
-rw-r--r-- 1 arthu arthu 148296926 Sep  1 15:07 fahcore-22-windows-64bit-release-0.0.20.tar.zst

$ rm  fahcore-22-windows-64bit-release-0.0.20.tar

$ time zstd -d fahcore-22-windows-64bit-release-0.0.20.tar.zst
fahcore-22-windows-64bit-release-0.0.20.tar.zst: 247808000 bytes

real    0m0.384s
user    0m0.156s
sys     0m0.125s

Both zstd and xz with BCJ compresses better than bzip2 and decompresses faster. Zstd is slightly smaller but very fast (34×). Xz is significantly smaller but only ~70% faster single-threaded.

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Slight issue with zstd is that it requires an pypi module python-zstandard; xz is covered by the builtin lzma module. Cbang, which is currently used to handle tar and bz2, also does not have zstd nor xz support in https://github.com/CauldronDevelopmentLLC/cbang/blob/master/src/cbang/iostream/CompressionFilter.h.