MAR 2010, version 0.45, Con Kolivas, Jari Aalto
* Fixed reported window size
* Fixed 32bit windows being attempted to be larger than contiguous amounts
by taking into account VM kernel/userspace split of 896MB.
* Minor code cleanups
* Added lrztar and lrunzip docs
* Fix minor typos
* Added distclean and maintainer-clean make targets
DEC 2009, version 0.44, Con Kolivas, George Makrydakis
* Added lrztar wrapper to manage whole directories.
* Added -i option to provide information about a compressed file.
* Fixed "nan" showing as Compression speed on very small files.
* Fixed build for old bz library.
* Avoid overwriting output file if input doesn't exist.
* Implement signal handler to delete temporary files.
DEC 2009, version 0.43, Con Kolivas, Jukka Laurila
* Darwin support thanks to Jukka Laurila.
* Finally added stdin/stdout support due to popular demand. This is done
by basically using temporary files so is a low performance way of using
* Added test function. This just uses a temporary file during decompression.
* Config files should now accept zpaq options.
* Minor code style cleanups.
* Updated benchmarks in docs.
* Add a warning when attempting to decompress a file from a newer lrzip
NOV 2009, version 0.42, Con Kolivas
* Changed progress update to show which of 2 chunks are being compressed
* Fixed progress update in ZPAQ to not update with each byte which was
wasting heaps of CPU time.
NOV 2009, version 0.41, Con Kolivas
* Added zpaq compression backend for extremely good but extremely slow
compression (incompatible with previous versions if used).
* Limited chunk size passed to LZMA to 4GB to avoid library overflows.
* Minor changes to the formatting output
* Changed lower limit of -T threshhold to 0 to allow disabling it.
* Added lzo_compresses check into zpaq and bzip2 as well since they're
NOV 2009, version 0.40, Con Kolivas
* Massive core code rewrite.
* All code moved to be 64bit based for compression block addressing and length
allowing compression windows to be limited by ram only.
* 64bit userspace should now have no restriction on compression window size,
32bit is still limited to 2GB windows due to userspace limitations.
* New file format using the new addressing and data types, incompatible with
versions prior to 0.40.
* Support for reading and decompressing older formats.
* Minor speedups in read/write routines.
* Countless minor code fixes throughout.
* Code style cleanups and consistency changes in core code.
* Configure script improvements.
NOV 2009, version 0.31, Con Kolivas
* Updated to be in sync with lzma SDK 9.07beta.
* Cleanups and fixes of the configure scripts to use the correct package version
* Massive fixes to the memory management code fixing lots of 32bit overflow
errors. The window size limit is now 2GB on both 32bit and 64bit. While it
appears to be smaller than the old windows, only 900MB was being used on .30
even though it claimed to use more. This can cause huge improvements in the
compression of very large files.
* The offset when mmap()ing was not being set to a multiple of page size so
it would fail if the window size was not a multiple of it.
* Flushing of data to disk between compression windows was implemented to
minimise disk thrashing of read vs write.
NOV 2009, version 0.30, Con Kolivas
* Numerous bugfixes to try and make the most of 64bit environments with huge
memory and to barf less on 32bit environments.
* Executable stacks were fixed.
* Probably other weird and wonderful bugs have been introduced.
* -P option to not set permissions on output files allowing you to write to
braindead filesystems (eg fat32).
JAN 2009, version 0.24, Peter Hyman, firstname.lastname@example.org
Happy New Year!
* Upgrade LZMA SDK to 4.63. Use new C Wrapper. Invalidates
LZMA archives created earlier due to new Magic property
* New LZMA logic will automatically determine allow LZMA
code to determine optimal lc, lp, pb, fb, and dictionary
size settings. stream.c will only pass level and thread
information. Compress function will return encoded 5 byte
data with compression settings. This will be stored in lrz
* add error messages during LZMA compression. There are some
edge cases where LZMA cannot allocate memory. These errors
are reported and the user will be advised to use a lower
compression window setting.
* type changes in rzip_fd function for correctness.
* remove function *Realloc() since it was never used. Cleaned
in rzip.h and util.c.
* apply munmap prior to closing and compressing stream in
function rzip_chunk in rzip.c.
* add realloc function in close_stream_out in stream.c
to reclaim some ram and try and allieviate out of memory
conditions in LZMA compression.
* remove file acconfig.h and include DEFINE in configure.in.
* add lrzip.conf capability.
* add timer for compression including elapsed time and eta.
* add compression and decompression MB/s calculation.
* Updated WHATS-NEW, TODO and created BUGS file.
* Updated lrzip.1 manpage and created lrzip.conf.5 manpage.
* Added lrzip.conf.example file in doc directory.
MAR 2008, Con Kolivas, email@example.com
* Numerous changes all over to place restrictions on window
size to work with 32 bit limitations.
* Various bugfixes with respect to detecting buffer sizes and
likelihood of compressibility.
* Fixed the inappropriate straight copying uncompressed data for
files larger than 4GB.
* Re-initiated the 10MB window limits for non-lzma compression.
I was unable to reproduce any file size savings.
* Allow compression windows larger than ramsize if people really
really want them.
* Decrease thresholds for the test function to a minimum of 5%
compressibility since the hanging in lzma compression bug has been
JAN 2008, version 0.22, Peter Hyman, firstname.lastname@example.org
* version update
Thanks to Lasse Collin for debugging the problem LZMA
had with hanging on uncompressable files.
Update for control parameters to both compress and
* use of @top_srcdir@ (Lasse Collin). Also moved away
main.c stream.c.rzip.h LZMALib.cpp lzmalib.h
* addition of three new control structure members.
control.lc -- literal context bits
control.lp -- literal post state bits
control.pb -- post state bits
These are needed to ensure decompression will work.
These will now be stored along with control.compression_level
in the lrz file beginning at offset 0x16 for three bytes.
These will be passed to the functions lzma_compresses and
lzma_uncompress. Currently, only compression level is
needed or used, but the others are stored for possible future
See magic file for more information.
* Change to lzo_compresses function that will reject a chunk
without testing it if the size of the chunk is greater
than the compression window * threshold. This is to avoid
a low probability that lzma would still be passed a chunk
that contains uncompressible data or barely compressible
data. If after rzip hashing the chunk size is still close
to the window size, there is hardly anything worth
compressing. While there is no reason lzma cannot get the
chunk, this will save a lot of time.
* updated file to show new layout that includes lzma
* added warning about using lrzip-0.22 with earlier versions.
* highlight of new features.
DEC 2007, version 0.21. Peter Hyman, email@example.com
* version update.
* Modified to use Assembler routines from lzma SDK for CRC
computation when hashing streams in rzip.c and runzip.c.
Added files 7zCrcT8.c and 7zCrcT8u.s to lzma tree.
Cleaned up source tree. Moved unused files out of the way.
Moved non-core docs to doc directory
* correct AC_INIT to set program variables.
* modified to add check for nasm assembler.
* modified syntax of test for errno in error.h to use
echo $ECHO_N/$ECHO_C instead of $ac_n/$ac_c which
* modified to add compile instructions for 7zCrcT8.c
and 7zCrcT8U.s and Assembler. Cleaned up to remove
targets that don't exist or sources that don't
Modified to properly set directories. Added doc install.
Add link command to symlink lrunzip to lrzip.
Add CrcGenerateTable() function to init CRC tables.
This is needed for all crc routines including those
rzip.c and runzip.c
* Updated source to change call to crc32_buffer to call
CrcUpdate in the assembler code. Changed parameter order
* Removed 10MB limit on streams for bzip, gzip, and lzo.
This, to improve effeciency of long range analysis. For
some files, this could improve results.
* Added file to keep benchmarks current to version.
(probably need to update README too).
* Explain how to remove default compile of Assembler
* added files for system detection.
DEC 2007, version 0.20. Peter Hyman, firstname.lastname@example.org
* Updated to LZMA SDK 4.57.
* Updated to p7zip POSIX version. (www.p7zip.org)
* Added multi-threading support (up to 2x speed with LZMA).
* Edited LZMADecompress.cpp for backward compatibility
with decompress function. Needed SetPropertiesRaw function.
* Repopulated source tree for distribution.
* Updated Makefile.in to reflect new source files.
Updated to include command to link lrunzip to lrzip because
lrzip will test if lrunzip was used on command line.
* Updated Makefile.in for new compile time and linking options.
* Updated LZMALibs.cpp to include new property members for
LZMAEncoders as well as changed default dictionaries to
level+16. This would make the default compression level
of 7 translate to a dictionary number of 23.
* Added output to show Nice Level when verbose mode set
Initial add of support for zlib which seems to give quite
* configure.in added AC_CHECK for libz and libm.
Added AC_PROG_LN_S for Makefile symlink section.
* lrzip.1 updated man page for -g option
* main.c added option test for gzip
Added sysconf(_SC_NPROCESSORS_CONF) for CPU detection
Updated verbose output to show whether or not
Threading will be used.
Added Timer for each file compressed.
* rzip.h added flags for GZIP compression.
Added control member for threads. Arg passed to
* stream.c update to accomodate gzip compress and decompress
functions. Cleaned up file by rearranging functions into
Removed include of lzmalib.h since it was causing a
compile time warning with zlib.h. Prototyped functions
Cleanup output from lzo_compresses function so that
unnecessary linefeeds are eliminated.
lzma_compress function call now uses threads as argument.
* Added README.benchmarks file to explain a method of
comparing results between different methods.
* LZMALib.cpp, lzmalib.h. Adjust function lzma_compress
prototype and function to include new argument threads.
This parameter is now placed in properties.
* lzma/Makefile. Updated to reflect new API library.
Updated to include Threading option.
DEC 2007, version 0.19. Con Kolivas.
* Added nice support, defaulting to nice 19.
DEC 2007, version 0.19. Peter Hyman, email@example.com
* Major goal was to stop LZMA from hanging on some files.
Accomplished this with a threhold setting that is used by
the lzo_compresses function to better analyze chunk data.
Threshold makes it less likely that uncompressible data
will be passed to the LZMA compressor.
* Added Threshold option 1-10 to control LZMA compression attempt.
Default value=2. This means that anything over 10% compression
as reported by lzo_compresses will return a true value to
the LZMA compression function.
* Added verbosity option and more verbosity option (-v[v]).
* Added -O option to specify output directory.
* Updated compress_file and decompress_file functions to handle.
output directories and better handle multi files and filename
extensions. Optimized some string handling routines.
Improved flexibility in determining location of output files
when using -O. Added fflush(stdout) to improve printf reliability.
* decompress_file will accept any filename and will automatically
append .lrz if not present. Won't automatically fail.
* Added logic to protect against conflicting options such as
-q and -v, -o and -O.
* Added printout to screen of options selected. Will display
only when -v or -vv used.
* Adjusted several printf statements to avoid compiler
warnings (use %ll for long long int types).
* Added decompression progress indicator.
Will show percent decompressed along with bytes decompressed
and total to be decompressed. Will show if -q option NOT used.
* Version incremented to 0.19.
* Added flag DEFINESs for verbosity and more verbosity.
* Updated control struct to include output directory and
threshold value. Removed verbosity member.
* Minor changes to handle display when verbosity set. Changed
number format in some printf statements to properly handle
* major overhaul of lzo_compresses function to use a threshold
value when testing a data chunk to see if it is suitable for
LZMA compression. Optimized test loop to improve performance
and reduce number of passes. Improved output reporting depending
on verbosity setting.
* Added print controls for verbosity option.
* Corrected if statements that tested for error condition of
some lzo functions that only return a true value regardless.
* updated man page to show new options and explain -T threshold.
* updated README to explain -T threshold option.
* Added this file to help explain the theory behind the rewrite
of the lzo_compresses function and how to use the -T option.
* wish list and future enhancements.
* added file.