HISTORY of the 7-Zip source code
--------------------------------

22.00          2022-06-16
-------------------------
- 7-Zip interfaces now support high precision (1 ns) timestamps with reserved
  fields of tagPROPVARIANT (VT_FILETIME).


21.07          2021-12-26
-------------------------
- The sorting order of files in archives was slightly changed to be more consistent
  for cases where the name of some directory is the same as the prefix part of the name
  of another directory or file.
- TAR archives created by 7-Zip now are more consistent with archives created by GNU TAR program.


21.06          2021-11-24
-------------------------
- Bug in LZMA encoder in file LzmaEnc.c was fixed:
  LzmaEnc_MemEncode(), LzmaEncode() and LzmaCompress() could work incorrectly, 
    if size value for output buffer is smaller than size required for all compressed data.
  LzmaEnc_Encode() could work incorrectly,
    if callback ISeqOutStream::Write() doesn't write all compressed data.
  NCompress::NLzma::CEncoder::Code() could work incorrectly,
    if callback ISequentialOutStream::Write() returns error code.
- Bug in versions 21.00-21.05 was fixed:
  7-Zip didn't set attributes of directories during archive extracting.


21.04 beta     2021-11-02
-------------------------
- 7-Zip now reduces the number of working CPU threads for compression,
  if RAM size is not enough for compression with big LZMA2 dictionary.
- 7-Zip now can create and check "file.sha256" and "file.sha1" text files 
  that contain the list of file names and SHA-1 / SHA-256 checksums in format 
  compatible with sha1sum/sha256sum programs.


21.03 beta     2021-07-20
-------------------------
- The maximum dictionary size for LZMA/LZMA2 compressing was increased to 4 GB (3840 MiB).
- Minor speed optimizations in LZMA/LZMA2 compressing.


21.02 alpha    2021-05-06
-------------------------
- 7-Zip now writes additional field for filename in UTF-8 encoding to zip archives.
  It allows to extract correct file name from zip archives on different systems.
- The command line version of 7-Zip for macOS was released.
- The speed for LZMA and LZMA2 decompression in arm64 versions for macOS and Linux 
  was increased by 20%-60%.
- Some changes and improvements in ZIP, TAR and NSIS code.


21.01 alpha    2021-03-09
-------------------------
- The command line version of 7-Zip for Linux was released.
- The improvements for speed of ARM64 version using hardware CPU instructions 
  for AES, CRC-32, SHA-1 and SHA-256.
- The bug in versions 18.02 - 21.00 was fixed:
  7-Zip could not correctly extract some ZIP archives created with xz compression method.
- Some bugs were fixed.


20.02 alpha    2020-08-08
-------------------------
- The default number of LZMA2 chunks per solid block in 7z archive was increased to 64.
  It allows to increase the compression speed for big 7z archives, if there is a big number 
  of CPU cores and threads.
- The speed of PPMd compressing/decompressing was increased for 7z/ZIP/RAR archives.
- The new -ssp switch. If the switch -ssp is specified, 7-Zip doesn't allow the system 
  to modify "Last Access Time" property of source files for archiving and hashing operations. 
- Some bugs were fixed.


20.00 alpha    2020-02-06
-------------------------
- 7-Zip now supports new optional match finders for LZMA/LZMA2 compression: bt5 and hc5, 
  that can work faster than bt4 and hc4 match finders for the data with big redundancy.
- The compression ratio was improved for Fast and Fastest compression levels with the 
  following default settings:
   - Fastest level (-mx1) : hc5 match finder with 256 KB dictionary.
   - Fast    level (-mx3) : hc5 match finder with 4 MB dictionary.
- Minor speed optimizations in multithreaded LZMA/LZMA2 compression for Normal/Maximum/Ultra 
  compression levels.
- bzip2 decoding code was updated to support bzip2 archives, created by lbzip2 program.


19.02          2019-09-05
-------------------------
- Support for SHA-1/SHA-256 optimized code in 
  Sha1Opt.c, Sha256Opt.c, Sha256Opt.asm, Sha1Opt.asm.


19.00          2019-02-21
-------------------------
- Encryption strength for 7z archives was increased:
  the size of random initialization vector was increased from 64-bit to 128-bit,
  and the pseudo-random number generator was improved.
- Some bugs were fixed.


18.06          2018-12-30
-------------------------
- The speed for LZMA/LZMA2 compressing was increased by 3-10%,
  and there are minor changes in compression ratio.
- Some bugs were fixed.
- The bug in 7-Zip 18.02-18.05 was fixed:
  There was memory leak in multithreading xz decoder - XzDecMt_Decode(),
  if xz stream contains only one block.
- 7-Zip 18.02-18.05 used only one CPU thread for bz2 archive creation.
- The changes for MSVS compiler makefiles: 
   - the makefiles now use "PLATFORM" macroname with values (x64, x86, arm64)
     instead of "CPU" macroname with values (AMD64, ARM64).
   - the makefiles by default now use static version of the run-time library.


18.05          2018-04-30
-------------------------
- The speed for LZMA/LZMA2 compressing was increased 
    by 8% for fastest/fast compression levels and 
    by 3% for normal/maximum compression levels.
- Previous versions of 7-Zip could work incorrectly in "Large memory pages" mode in
  Windows 10 because of some BUG with "Large Pages" in Windows 10. 
  Now 7-Zip doesn't use "Large Pages" on Windows 10 up to revision 1709 (16299).


18.03 beta     2018-03-04
-------------------------
- Asm\x86\LzmaDecOpt.asm: new optimized LZMA decoder written in asm 
  for x64 with about 30% higher speed than main version of LZMA decoder written in C.
- The speed for single-thread LZMA/LZMA2 decoder written in C was increased by 3%.
- 7-Zip now can use multi-threading for 7z/LZMA2 decoding,
  if there are multiple independent data chunks in LZMA2 stream.
- 7-Zip now can use multi-threading for xz decoding,
  if there are multiple blocks in xz stream.


17.00 beta     2017-04-29
-------------------------
- NewHandler.h / NewHandler.cpp: 
    now it redefines operator new() only for old MSVC compilers (_MSC_VER < 1900).
- C/7zTypes.h : the names of variables in interface structures were changed (vt).
- Some bugs were fixed. 7-Zip could crash in some cases.
- Some internal changes in code.


16.02          2016-05-21
-------------------------
- The BUG in 16.00 - 16.01 was fixed:
  Split Handler (SplitHandler.cpp) returned incorrect 
  total size value (kpidSize) for split archives.


16.01          2016-05-19
-------------------------	
- Some bugs were fixed,
- Some internal changes to reduce the number of compiler warnings.


16.00          2016-05-10
-------------------------	
- 7-Zip now can extract multivolume ZIP archives (z01, z02, ... , zip).
- Some bugs were fixed,


15.12          2015-11-19
-------------------------	
- The BUG in C version of 7z decoder was fixed:
  7zDec.c : SzDecodeLzma2()
  7z decoder could mistakenly report about decoding error for some 7z archives
  that use LZMA2 compression method.
  The probability to get that mistaken decoding error report was about 
  one error per 16384 solid blocks for solid blocks larger than 16 KB (compressed size). 
- The BUG (in 9.26-15.11) in C version of 7z decoder was fixed:
  7zArcIn.c : SzReadHeader2()
  7z decoder worked incorrectly for 7z archives that contain 
  empty solid blocks, that can be placed to 7z archive, if some file is 
  unavailable for reading during archive creation.


15.09 beta     2015-10-16
-------------------------	
- The BUG in LZMA / LZMA2 encoding code was fixed.
  The BUG in LzFind.c::MatchFinder_ReadBlock() function.
  If input data size is larger than (4 GiB - dictionary_size),
  the following code worked incorrectly:
  -  LZMA : LzmaEnc_MemEncode(), LzmaEncode() : LZMA encoding functions 
     for compressing from memory to memory. 
     That BUG is not related to LZMA encoder version that works via streams.
  -  LZMA2 : multi-threaded version of LZMA2 encoder worked incorrectly, if 
     default value of chunk size (CLzma2EncProps::blockSize) is changed 
     to value larger than (4 GiB - dictionary_size).


9.38 beta      2015-01-03
-------------------------	
- The BUG in 9.31-9.37 was fixed:
  IArchiveGetRawProps interface was disabled for 7z archives.
- The BUG in 9.26-9.36 was fixed:
  Some code in CPP\7zip\Archive\7z\ worked correctly only under Windows.


9.36 beta      2014-12-26
-------------------------	
- The BUG in command line version was fixed:
  7-Zip created temporary archive in current folder during update archive
  operation, if -w{Path} switch was not specified. 
  The fixed 7-Zip creates temporary archive in folder that contains updated archive.
- The BUG in 9.33-9.35 was fixed:
  7-Zip silently ignored file reading errors during 7z or gz archive creation,
  and the created archive contained only part of file that was read before error.
  The fixed 7-Zip stops archive creation and it reports about error.


9.31           2012-10-31
-------------------------
- InBuffer.h : CInBuffer  uses ISequentialInStream  *_stream; instead of CMyComPtr<ISequentialInStream> 
  OutBuffer.h: COutBuffer uses ISequentialOutStream *_stream; instead of CMyComPtr<ISequentialOutStream> 
	

9.26           2011-04-11
-------------------------
- The BUG was fixed: multi-threaded ZIP stored file size that was at scan stage,
  So if the file was changed after scan, the Unpack Size field was incorrect
	

9.21           2011-04-11
-------------------------	
- New class FString for file names at file systems.
- Speed optimization in CRC code for big-endian CPUs.


9.18           2010-11-02
-------------------------	
- New small SFX module for installers (C/Util/SfxSetup).


9.17           2010-10-04
-------------------------
- IStream.h::IOutStream::
    STDMETHOD(SetSize)(Int64 newSize) PURE;
  was changed to
    STDMETHOD(SetSize)(UInt64 newSize) PURE;


9.09           2009-12-12
-------------------------
- The bug was fixed:
   Utf16_To_Utf8 funstions in UTFConvert.cpp and 7zMain.c
   incorrectly converted surrogate characters (the code >= 0x10000) to UTF-8.


9.05           2009-07-05
-------------------------
- FileMapping.h::CFileMapping now returns WRes


9.04           2009-05-30
-------------------------
- ICoder.h: NCoderPropID::EEnum values were changed


9.02           2009-04-23
-------------------------
- Bug was fixed: if swap2 filter was requests at compression,
  7-zip used swap4 filter instead (but id was swap2), so archives were incorrect.
  
4.61           2008-11-23
-------------------------
- Bug in ver. 4.58+ was fixed:
   7-Zip didn't use any -m* switch after -mtc, -mcl or -mcu for .zip archives. 
- Bug in .CAB code was fixed. 7-Zip didn't show some empty files,
  if .CAB archive contains more than one empty file.
   

4.59           2008-07-27
-------------------------
- Bug was fixed:
   LZMA Encoder in fast compression mode could access memory outside of 
   allocated range in some rare cases.
   

4.59 alpha     2008-05-30
-------------------------
- BUGS was fixed: 
    7zOut.cpp: 7-Zip incorrectly wrote size of property records in some cases.
    7zIn.cpp:  7-Zip incorrectly work with archive, containg archive properties.

4.58 alpha 9   2008-04-29
-------------------------
- BUG was fixed: 7-Zip showed incorrect timestamps in ISO files.


4.58 alpha 8   2008-04-15
-------------------------
- BUG in 4.58 alpha 5/6/7 was fixed:
    LZMA encoder worked incorrectly, if lp != 0.
- Unicode (UTF-8) support for filenames in .ZIP archives. Now there are 3 modes:
    1) Default mode: 7-Zip uses UTF-8, if the local code page doesn't contain required symbols.
    2) -mcu switch:  7-Zip uses UTF-8, if there are non-ASCII symbols.
    3) -mcl switch:  7-Zip uses local code page.
- Now it's possible to use -mSW- and -mSW+ switches instead of -mSW=off and -mSW=on  


4.58 alpha 7   2008-04-08
-------------------------
- BUG was fixed: BZip2Encoder and BZip2Decoder used CEvent objects without 
  creating, when BZip2 code was called with one thread (with -mmt1 switch or with 
  default switches on single thread CPU).
- .lzma support.
- RPM and NSIS support was improved.
- LZMA now stores only (2 << n) or (3 << n) dictionary size value to LZMA properties.


4.58 alpha 6   2008-03-27
-------------------------
- NTFS time extra in ZIP.
- New item property - kpidTimeType - VT_UI4 (0 - NTFS, 1 - Unix, 2 - DOS).
- Static CRC table is not required now for Lzma Encoder (in Lz MatchFinder).


4.58 alpha 5   2008-03-19
-------------------------
- Creation time (-mtc switch) for .7z archives
- LZMA encoder was converted to ANSI-C


4.58 alpha 3   2008-02-25
-------------------------
- Speed optimizations for LZMA decoding. Now it uses C code instead of C++.
- 7-Zip now has 128 MB dictionary limit for 32-bit version:
  It's for speed optimization: kNumLogBits = 9 + sizeof(size_t) / 2;
- TAR: 'D' link flag support.
- 7-Zip now can unpack multivolume RAR archives created with 
  "old style volume names" scheme (-vn switch) and names *.001, *.002, ...
- Fixed bugs:
  - 7-Zip FM could not copy / move files to root network folders like \\COMPNAME\FOLDERNAME\
    In case of move it removed original files.
  - SFX-WIN: if there are errors, it still could return 0.
  - ZIP (.XPS file) isZip64 && thisDiskNumber16 == 0xFFFF.
  - ZIP name updating:
      If zip file contains extra field and you try to change properties of files,
      7-zip tries to delete all extra fileds (except for WzAES).
      And that code could hang.
  -  7-Zip GUI didn't suggest BZip2 dictionary size used in previous run.
  -  If creation time stamp was included in .RAR archive, 7-zip used creation time stamp 
     as modification time stamp.

4.58 alpha 2   2007-12-31
-------------------------
- Small changes in Deflate and LZMA compression.
- Some speed optimizations.


4.57
----
- Bug was fixed:
  Anti item is created for wrong file:
  http://sourceforge.net/forum/forum.php?thread_id=1880366&forum_id=45798


4.52 beta      2007-07-32
-------------------------
- 7-Zip could not decompress some cab files
- "." dir creating at FAT was fixed / long names


4.50 beta      2007-07-24
-------------------------
- 7-Zip now replaces unsupported filenames (like "nul", "com1") during extracting.
- New switch for command line version:
    -ssc[-] enables/disables case-sensitive mode.
- 7z.exe l shows archive comment for zip archives
- Some bugs were fixed: long paths names shorter than 4.
- Speed optimizations for AES encryption.



4.56 beta      2007-09-13
-------------------------
- some fixes in LZ encoder (LZMA and Deflate) code.
 size_t was replaces to ptrdiff_t.
 size_t version worked incorrectly with some compilers.

 
4.46 beta      2007-05-25
-------------------------
- CPP Synchronization objects now return HRes (error code) instead of bool.


4.45 beta      2007-04-16
-------------------------
- 7-Zip now uses C version of CRC, so you must call CrcGenerateTable at 
  stratup code, or you must add CPP/Common/CRC.cpp to your project.
- Method ID in .7z now is 63-bit integer (UInt64).
- Open error messages
- unRar 1.5 fixed
- unShrink fixed
- BUG of 4.43 beta and 4.44 beta was fixed.
  7-Zip compressing to .zip in multi-threading mode didn't work in some cases.


4.44 beta      2007-01-20
-------------------------

- Bug was fixed: LZMAEncoder.cpp::CEncoder::GetOptimumFast
  it was:
    data++
  fixed version:
    data = _matchFinder.GetPointerToCurrentPos(_matchFinderObj) - 1;
  It could lead to very small cpmpression ratio decreasing when block needs move.


4.30 beta      2005-11-18
-------------------------
- Security.h::AddLockMemoryPrivilege       - installs "Large pages" feature
- MemoryLock.h::EnableLockMemoryPrivilege  - enables "Large pages" feature
- Alloc.h::SetLargePageSize                - sets optimal LargePageSize size


4.27           2005-09-21
-------------------------
- Some GUIDs/interfaces were changed.
 IStream.h:
   ISequentialInStream::Read now works as old ReadPart
   ISequentialOutStream::Write now works as old WritePart


4.26 beta      2005-08-05
-------------------------
-  MyAlloc(0)/BigAlloc(0) now return 0


4.25 beta      2005-07-31
-------------------------
-  More 64-bit compatibilty


4.24 beta      2005-07-06
-------------------------
-  Common\NewHandler.h: using throw() for code size optimization.


4.23           2005-06-29
-------------------------
-  Bug was fixed: memory leak in Cab decoder.


4.19 beta      2005-05-21
-------------------------
-  BZip2 code was rewritten. Now 7-Zip doesn't use original BZip2 code.
  Old (original) version was moved to folder 7zip/Compress/BZip2Original/


4.14 beta      2005-01-11
-------------------------
-  STL using was reduced
-  7za now supports Split(001) archves


4.10 beta      2004-10-21
-------------------------
-  Codecs now use new interface: ICompressSetDecoderProperties2


4.07 beta      2004-10-03
-------------------------
-  some interfaces were changed slightly to support 
  -stdin -stdout mode.
-  FilterCoder for simple filters
-  Wildcard censor class was changed.
-  Bug was fixed: when encrypted stream was multiple 16,
  it used additional 16 empty bytes.


3.11           2003-10-06
-------------------------
  File functions support unicode strings even
  on Windows 95/98/ME.


3.08.02        2003-09-20
-------------------------
  More compatible with GCC.


3.08.02 beta   2003-08-20
-------------------------
  Extracting bug in 7zExtract.cpp was fixed.
 

3.08 beta      2003-08-19
-------------------------
  Big source code reconstruction.
 

2.30 Beta 32   2003-05-15
-------------------------
  Small changes in Deflate decoder.
 

2.30 Beta 31   2003-04-29
-------------------------
  Common/NewHandler.cpp
    HeapAlloc in (included to beta 30) was changed to malloc.
    HeapAlloc worked slower in Win95/98/Me.
 

2.30 Beta 30   2003-04-21
-------------------------
  new file: Common/String.cpp
  Common/NewHandler.*  were changed


2.30 Beta 29   2003-04-07
-------------------------
  Small changes in LZMA code.


2.30 Beta 28   2003-02-16
-------------------------
  Processing anti-files was corrected.


2.30 Beta 27   2003-01-24
-------------------------
  Project/Archiver/Format/Common/ArchiveInterface.h:
    new IArchiveOpenVolumeCallback interface.


2.30 Beta 26   2003-01-12
-------------------------
  SDK/Interface/PropID.h:
    kpidComment now is kpidCommented


2.30 Beta 25   2003-01-02
-------------------------
  Main archive interfaces were changed.


2.30 Beta 24   2002-11-01
-------------------------
  SDK/Windows/Synchronization.h 
  SDK/Windows/Synchronization.cpp
    - some changes.


2.30 Beta 23   2002-09-07
-------------------------
  Project/FileManager folder was added.
  Notation of some source files was changed.


2.30 Beta 22   2002-08-28
-------------------------
  Project/FileManager folder was added.
  Notation of some source files was changed.



2.30 Beta 21   2002-07-08
-------------------------
  Project/Compress/LZ/MatchFinder/BinTree/BinTree.h
  Project/Compress/LZ/MatchFinder/BinTree/BinTreeMain.h
  Project/Compress/LZ/MatchFinder/BinTree/HC.h
  Project/Compress/LZ/MatchFinder/BinTree/HCMain.h
    - RAM requirements for LZMA (7z) compression were reduced.


2.30 Beta 20   2002-07-01
-------------------------
- SDK/Stream/WindowOut.h 
    now it uses only required memory (dictionary size).
- Project/Archiver/Resource 
    contains common resurces


2.30 Beta 19   2002-04-11
-------------------------
- SDK/Archive/Rar/Handler.cpp
    supporting RAR29

2.30 Beta 18   2002-03-25
-------------------------
- SDK/Archive/Cab/MSZipDecoder.cpp
  SDK/Archive/Cab/LZXDecoder.cpp:
    bug with corrupted archives was fixed
- Project/Compress/LZ/MatchFinder/BinTree/BinTree.h 
- Project/Compress/LZ/MatchFinder/BinTree/BinTreeMain.h 
    some speed optimization (using prefetching)


2.30 Beta 17   2002-03-03
-------------------------
- ARJ suppport.


2.30 Beta 16   2002-02-24
-------------------------
- Project/Compress/LZ/LZMA/Decoder.cpp:
    Bug was fixed: LZMA could not extract more than 4 GB.
- RPM and CPIO formats.
- Project/Compress/LZ/LZMA/Encoder.*
  Project/Archiver/Format/7z/OutHandler.cpp 
    New fast compression mode for LZMA: -m0a=0.
- New match finders for LZMA: bt4b, hc3, hc4.


2.30 Beta 15   2002-02-17
-------------------------
- Compression ratio in LZMA was slightly improved:
    Project/Compress/LZ/LZMA/Encoder.*
    Project/Archiver/Format/7z/OutHandler.cpp 


2.30 Beta 14   2002-02-10
-------------------------
- Supporting multithreading for LZMA:
    Project/Compress/LZ/MatchFinder/MT 
- Common/String.h:
    CStringBase::Replace function was fixed.


2.30 Beta 13   2002-01-27
-------------------------
- Compress/LZ/MatchFinder/BinTree3.h: 
   method
- Compress/LZ/MatchFinder/BinTreemain.h: 
    - one VirtualAlloc array was splitted to 
      the for 3 arrays.
    - Hash-functions were changed.



2.30 Beta 12   2002-01-16
-------------------------
- Compress/LZ/MatchFinder/BinTreemain.h: 
  Compress/LZ/MatchFinder/Patricia.h: 
  Compress/PPM/PPMd/SubAlloc.h: 
    Beta 11 bugs were fixed:
      - VirtualFree was used incorrectly
      - checking WIN32 instead _WINDOWS.
  Compress/LZ/MatchFinder/Patricia.h: 
    Beta 11 bug with deleting m_Hash2Descendants was fixed.


2.30 Beta 11   2002-01-15
-------------------------
- Compress/LZ/MatchFinder/BinTreemain.h: 
  Compress/LZ/MatchFinder/Patricia.h: 
  Compress/PPM/PPMd/SubAlloc.h: 
    using VirtualAlloc for memory allocating
- Exlorer/ContextMenu.cpp: 
    Testing supporting.
    CreateProcess instead WinExec
- Format/Common/IArchiveHandler.h:
  Exlorer/ProxyHandler.cpp:
  FAR/Plugin.cpp:
    New properties names: Method, HostOS.
- Exlorer/OverwriteDialog.cpp:
  FAR/OverwriteDialog.cpp:
  Windows/PropVariantConversions.h
    Using National time format was eliminated.



2.30 Beta 10   2002-01-11
-------------------------
- Exlorer/ContextMenu.cpp: bug with context menu on 
  Windows NT4 in Unicode version was fixed.
- Format/7z/UpdateArchiveEngine.cpp: bug was fixed - 
  Updating in Beta 8 and 9 didn't work.
- Exlorer/CCompressDialog.cpp: history growing bug was fixed.


2.30 Beta 9    2002-01-08
-------------------------
- SDK/Common/Vector.h: sopporting sorted object vectors .
- Lang features.
- Two new match finders: pat3h and pat4h.
- SDK/Archive/Zip/InEngine.cpp: bug was fixed.
- SDK/Windows/FileDir.cpp: function CreateComplexDirectory
  was changed.

