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| author | Jia Tan <jiat0218@gmail.com> | 2023-12-15 23:57:06 +0800 |
|---|---|---|
| committer | Jia Tan <jiat0218@gmail.com> | 2024-01-19 23:36:34 +0800 |
| commit | f2090365d4cdc86020beb1ac8aea43444cf2456c (patch) | |
| tree | 5e598575988c0ae1e8fc7cde839e24f7f392b22f | |
| parent | a5390fd368f8a58401c0ce0dfb9d05ef3046e4a3 (diff) | |
| download | xz-embedded-f2090365d4cdc86020beb1ac8aea43444cf2456c.tar.gz | |
Minor README updates.
This rewords a few minor things. Additionally, the table macros was
updated to include the forgotten XZ_DEC_ARM64 and to note that the ARM
based architectures can use the filters in little or big endian mode, as
long as the instructions are in little endian mode. Modern ARM
architectures use little endian instruction encoding, even if other data
is encoded big endian.
| -rw-r--r-- | README | 30 |
1 files changed, 13 insertions, 17 deletions
@@ -90,7 +90,7 @@ Supporting concatenated .xz files Regular .xz files can be concatenated as is and the xz command line tool will decompress all streams from a concatenated file (a few other popular formats and tools support this too). This kind of .xz - files aren't as uncommon as one might think because pxz, an early + files are more common than one might think because pxz, an early threaded XZ compressor, created this kind of .xz files. The xz_dec_run() function will stop after decompressing one stream. @@ -138,7 +138,7 @@ Integrity check support BCJ filter support - If you want support for one or more BCJ filters, you need to copy also + If you want support for one or more BCJ filters, you need to copy linux/lib/xz/xz_dec_bcj.c into your application, and use appropriate #defines in xz_config.h or in compiler flags. You don't need these #defines in the code that just uses XZ Embedded via xz.h, but having @@ -148,28 +148,24 @@ BCJ filter support XZ_DEC_X86 x86-32 or x86-64 Little endian only XZ_DEC_POWERPC PowerPC Big endian only XZ_DEC_IA64 Itanium (IA-64) Big or little endian - XZ_DEC_ARM ARM Little endian only - XZ_DEC_ARMTHUMB ARM-Thumb Little endian only + XZ_DEC_ARM ARM Little endian instructions + XZ_DEC_ARMTHUMB ARM-Thumb Big or little endian + XZ_DEC_ARM64 ARM64 Big or little endian XZ_DEC_SPARC SPARC Big or little endian While some architectures are (partially) bi-endian, the endianness setting doesn't change the endianness of the instructions on all - architectures. That's why Itanium and SPARC filters work for both big - and little endian executables (Itanium has little endian instructions - and SPARC has big endian instructions). - - There currently is no filter for little endian PowerPC or big endian - ARM or ARM-Thumb. Implementing filters for them can be considered if - there is a need for such filters in real-world applications. + architectures. That's why many filters work for both big and little + endian executables (Itanium and ARM based architectures have little + endian instructions and SPARC has big endian instructions). Notes about shared libraries - If you are including XZ Embedded into a shared library, you very - probably should rename the xz_* functions to prevent symbol - conflicts in case your library is linked against some other library - or application that also has XZ Embedded in it (which may even be - a different version of XZ Embedded). TODO: Provide an easy way - to do this. + If you are including XZ Embedded into a shared library, you should + rename the xz_* functions to prevent symbol conflicts in case your + library is linked against some other library or application that + also has XZ Embedded in it (which may even be a different version + of XZ Embedded). Please don't create a shared library of XZ Embedded itself unless it is fine to rebuild everything depending on that shared library |