aaa2975f2b
MicroLZMA is a yet another header format variant where the first byte of a raw LZMA stream (without the end of stream marker) has been replaced with a bitwise-negation of the lc/lp/pb properties byte. MicroLZMA was created to be used in EROFS but can be used by other things too where wasting minimal amount of space for headers is important. This is implemented using most of the LZMA2 code as is so the amount of new code is small. The API has a few extra features compared to the XZ decoder. On the other hand, the API lacks XZ_BUF_ERROR support which is important to take into account when using this API. MicroLZMA doesn't support BCJ filters. In theory they could be added later as there are many unused/reserved values for the first byte of the compressed stream but in practice it is somewhat unlikely to happen due to a few implementation reasons. Link: https://lore.kernel.org/r/20211010213145.17462-5-xiang@kernel.org Signed-off-by: Lasse Collin <lasse.collin@tukaani.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
1.7 KiB
SPDX-License-Identifier: GPL-2.0-only
config XZ_DEC tristate "XZ decompression support" select CRC32 help LZMA2 compression algorithm and BCJ filters are supported using the .xz file format as the container. For integrity checking, CRC32 is supported. See Documentation/staging/xz.rst for more information.
if XZ_DEC
config XZ_DEC_X86 bool "x86 BCJ filter decoder" if EXPERT default y select XZ_DEC_BCJ
config XZ_DEC_POWERPC bool "PowerPC BCJ filter decoder" if EXPERT default y select XZ_DEC_BCJ
config XZ_DEC_IA64 bool "IA-64 BCJ filter decoder" if EXPERT default y select XZ_DEC_BCJ
config XZ_DEC_ARM bool "ARM BCJ filter decoder" if EXPERT default y select XZ_DEC_BCJ
config XZ_DEC_ARMTHUMB bool "ARM-Thumb BCJ filter decoder" if EXPERT default y select XZ_DEC_BCJ
config XZ_DEC_SPARC bool "SPARC BCJ filter decoder" if EXPERT default y select XZ_DEC_BCJ
config XZ_DEC_MICROLZMA bool "MicroLZMA decoder" default n help MicroLZMA is a header format variant where the first byte of a raw LZMA stream (without the end of stream marker) has been replaced with a bitwise-negation of the lc/lp/pb properties byte. MicroLZMA was created to be used in EROFS but can be used by other things too where wasting minimal amount of space for headers is important.
Unless you know that you need this, say N.
endif
config XZ_DEC_BCJ bool default n
config XZ_DEC_TEST tristate "XZ decompressor tester" default n depends on XZ_DEC help This allows passing .xz files to the in-kernel XZ decoder via a character special file. It calculates CRC32 of the decompressed data and writes diagnostics to the system log.
Unless you are developing the XZ decoder, you don't need this
and should say N.