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@@ -2,6 +2,208 @@ XZ Utils Release Notes ====================== +5.4.0 (2022-12-13) + + This bumps the minor version of liblzma because new features were + added. The API and ABI are still backward compatible with liblzma + 5.2.x and 5.0.x. + + Since 5.3.5beta: + + * All fixes from 5.2.10. + + * The ARM64 filter is now stable. The xz option is now --arm64. + Decompression requires XZ Utils 5.4.0. In the future the ARM64 + filter will be supported by XZ for Java, XZ Embedded (including + the version in Linux), LZMA SDK, and 7-Zip. + + * Translations: + + - Updated Catalan, Croatian, German, Romanian, and Turkish + translations. + + - Updated German man page translations. + + - Added Romanian man page translations. + + Summary of new features added in the 5.3.x development releases: + + * liblzma: + + - Added threaded .xz decompressor lzma_stream_decoder_mt(). + It can use multiple threads with .xz files that have multiple + Blocks with size information in Block Headers. The threaded + encoder in xz has always created such files. + + Single-threaded encoder cannot store the size information in + Block Headers even if one used LZMA_FULL_FLUSH to create + multiple Blocks, so this threaded decoder cannot use multiple + threads with such files. + + If there are multiple Streams (concatenated .xz files), one + Stream will be decompressed completely before starting the + next Stream. + + - A new decoder flag LZMA_FAIL_FAST was added. It makes the + threaded decompressor report errors soon instead of first + flushing all pending data before the error location. + + - New Filter IDs: + * LZMA_FILTER_ARM64 is for ARM64 binaries. + * LZMA_FILTER_LZMA1EXT is for raw LZMA1 streams that don't + necessarily use the end marker. + + - Added lzma_str_to_filters(), lzma_str_from_filters(), and + lzma_str_list_filters() to convert a preset or a filter chain + string to a lzma_filter[] and vice versa. These should make + it easier to write applications that allow users to specify + custom compression options. + + - Added lzma_filters_free() which can be convenient for freeing + the filter options in a filter chain (an array of lzma_filter + structures). + + - lzma_file_info_decoder() to makes it a little easier to get + the Index field from .xz files. This helps in getting the + uncompressed file size but an easy-to-use random access + API is still missing which has existed in XZ for Java for + a long time. + + - Added lzma_microlzma_encoder() and lzma_microlzma_decoder(). + It is used by erofs-utils and may be used by others too. + + The MicroLZMA format is a raw LZMA stream (without end marker) + whose first byte (always 0x00) has been replaced with + bitwise-negation of the LZMA properties (lc/lp/pb). It was + created for use in EROFS but may be used in other contexts + as well where it is important to avoid wasting bytes for + stream headers or footers. The format is also supported by + XZ Embedded (the XZ Embedded version in Linux got MicroLZMA + support in Linux 5.16). + + The MicroLZMA encoder API in liblzma can compress into a + fixed-sized output buffer so that as much data is compressed + as can be fit into the buffer while still creating a valid + MicroLZMA stream. This is needed for EROFS. + + - Added lzma_lzip_decoder() to decompress the .lz (lzip) file + format version 0 and the original unextended version 1 files. + Also lzma_auto_decoder() supports .lz files. + + - lzma_filters_update() can now be used with the multi-threaded + encoder (lzma_stream_encoder_mt()) to change the filter chain + after LZMA_FULL_BARRIER or LZMA_FULL_FLUSH. + + - In lzma_options_lzma, allow nice_len = 2 and 3 with the match + finders that require at least 3 or 4. Now it is internally + rounded up if needed. + + - CLMUL-based CRC64 on x86-64 and E2K with runtime processor + detection. On 32-bit x86 it currently isn't available unless + --disable-assembler is used which can make the non-CLMUL + CRC64 slower; this might be fixed in the future. + + - Building with --disable-threads --enable-small + is now thread-safe if the compiler supports + __attribute__((__constructor__)). + + * xz: + + - Using -T0 (--threads=0) will now use multi-threaded encoder + even on a single-core system. This is to ensure that output + from the same xz binary is identical on both single-core and + multi-core systems. + + - --threads=+1 or -T+1 is now a way to put xz into + multi-threaded mode while using only one worker thread. + The + is ignored if the number is not 1. + + - A default soft memory usage limit is now used for compression + when -T0 is used and no explicit limit has been specified. + This soft limit is used to restrict the number of threads + but if the limit is exceeded with even one thread then xz + will continue with one thread using the multi-threaded + encoder and this limit is ignored. If the number of threads + is specified manually then no default limit will be used; + this affects only -T0. + + This change helps on systems that have very many cores and + using all of them for xz makes no sense. Previously xz -T0 + could run out of memory on such systems because it attempted + to reserve memory for too many threads. + + This also helps with 32-bit builds which don't have a large + amount of address space that would be required for many + threads. The default soft limit for -T0 is at most 1400 MiB + on all 32-bit platforms. + + - Previously a low value in --memlimit-compress wouldn't cause + xz to switch from multi-threaded mode to single-threaded mode + if the limit cannot otherwise be met; xz failed instead. Now + xz can switch to single-threaded mode and then, if needed, + scale down the LZMA2 dictionary size too just like it already + did when it was started in single-threaded mode. + + - The option --no-adjust no longer prevents xz from scaling down + the number of threads as that doesn't affect the compressed + output (only performance). Now --no-adjust only prevents + adjustments that affect compressed output, that is, with + --no-adjust xz won't switch from multi-threaded mode to + single-threaded mode and won't scale down the LZMA2 + dictionary size. + + - Added a new option --memlimit-mt-decompress=LIMIT. This is + used to limit the number of decompressor threads (possibly + falling back to single-threaded mode) but it will never make + xz refuse to decompress a file. This has a system-specific + default value because without any limit xz could end up + allocating memory for the whole compressed input file, the + whole uncompressed output file, multiple thread-specific + decompressor instances and so on. Basically xz could + attempt to use an insane amount of memory even with fairly + common files. The system-specific default value is currently + the same as the one used for compression with -T0. + + The new option works together with the existing option + --memlimit-decompress=LIMIT. The old option sets a hard limit + that must not be exceeded (xz will refuse to decompress) + while the new option only restricts the number of threads. + If the limit set with --memlimit-mt-decompress is greater + than the limit set with --memlimit-compress, then the latter + value is used also for --memlimit-mt-decompress. + + - Added new information to the output of xz --info-memory and + new fields to the output of xz --robot --info-memory. + + - In --lzma2=nice=NUMBER allow 2 and 3 with all match finders + now that liblzma handles it. + + - Don't mention endianness for ARM and ARM-Thumb filters in + --long-help. The filters only work for little endian + instruction encoding but modern ARM processors using + big endian data access still use little endian + instruction encoding. So the help text was misleading. + In contrast, the PowerPC filter is only for big endian + 32/64-bit PowerPC code. Little endian PowerPC would need + a separate filter. + + - Added decompression support for the .lz (lzip) file format + version 0 and the original unextended version 1. It is + autodetected by default. See also the option --format on + the xz man page. + + - Sandboxing enabled by default: + * Capsicum (FreeBSD) + * pledge(2) (OpenBSD) + + * Scripts now support the .lz format using xz. + + * A few new tests were added. + + * The liblzma-specific tests are now supported in CMake-based + builds too ("make test"). + + 5.3.5beta (2022-12-01) * All fixes from 5.2.9. |