IntelFrameworkModulePkg/Library/LzmaCustomDecompressLib/Sdk/DOC/lzma-sdk.txt - device/linaro/bootloader/edk2 - Git at Google

 LZMA SDK 16.04
 --------------

 LZMA SDK provides the documentation, samples, header files,
 libraries, and tools you need to develop applications that
 use 7z / LZMA / LZMA2 / XZ compression.

 LZMA is an improved version of famous LZ77 compression algorithm.
 It was improved in way of maximum increasing of compression ratio,
 keeping high decompression speed and low memory requirements for
 decompressing.

 LZMA2 is a LZMA based compression method. LZMA2 provides better
 multithreading support for compression than LZMA and some other improvements.

 7z is a file format for data compression and file archiving.
 7z is a main file format for 7-Zip compression program (www.7-zip.org).
 7z format supports different compression methods: LZMA, LZMA2 and others.
 7z also supports AES-256 based encryption.

 XZ is a file format for data compression that uses LZMA2 compression.
 XZ format provides additional features: SHA/CRC check, filters for
 improved compression ratio, splitting to blocks and streams,


 LICENSE
 -------

 LZMA SDK is written and placed in the public domain by Igor Pavlov.

 Some code in LZMA SDK is based on public domain code from another developers:
   1) PPMd var.H (2001): Dmitry Shkarin
   2) SHA-256: Wei Dai (Crypto++ library)

 Anyone is free to copy, modify, publish, use, compile, sell, or distribute the
 original LZMA SDK code, either in source code form or as a compiled binary, for
 any purpose, commercial or non-commercial, and by any means.

 LZMA SDK code is compatible with open source licenses, for example, you can
 include it to GNU GPL or GNU LGPL code.


 LZMA SDK Contents
 -----------------

   Source code:

     - C / C++ / C# / Java   - LZMA compression and decompression
     - C / C++               - LZMA2 compression and decompression
     - C / C++               - XZ compression and decompression
     - C                     - 7z decompression
     -     C++               - 7z compression and decompression
     - C                     - small SFXs for installers (7z decompression)
     -     C++               - SFXs and SFXs for installers (7z decompression)

   Precomiled binaries:

     - console programs for lzma / 7z / xz compression and decompression
     - SFX modules for installers.


 UNIX/Linux version
 ------------------
 To compile C++ version of file->file LZMA encoding, go to directory
 CPP/7zip/Bundles/LzmaCon
 and call make to recompile it:
   make -f makefile.gcc clean all

 In some UNIX/Linux versions you must compile LZMA with static libraries.
 To compile with static libraries, you can use
 LIB = -lm -static

 Also you can use p7zip (port of 7-Zip for POSIX systems like Unix or Linux):

   http://p7zip.sourceforge.net/


 Files
 -----

 DOC/7zC.txt          - 7z ANSI-C Decoder description
 DOC/7zFormat.txt     - 7z Format description
 DOC/installer.txt    - information about 7-Zip for installers
 DOC/lzma.txt         - LZMA compression description
 DOC/lzma-sdk.txt     - LZMA SDK description (this file)
 DOC/lzma-history.txt - history of LZMA SDK
 DOC/lzma-specification.txt - Specification of LZMA
 DOC/Methods.txt      - Compression method IDs for .7z

 bin/installer/   - example script to create installer that uses SFX module,

 bin/7zdec.exe    - simplified 7z archive decoder
 bin/7zr.exe      - 7-Zip console program (reduced version)
 bin/x64/7zr.exe  - 7-Zip console program (reduced version) (x64 version)
 bin/lzma.exe     - file->file LZMA encoder/decoder for Windows
 bin/7zS2.sfx     - small SFX module for installers (GUI version)
 bin/7zS2con.sfx  - small SFX module for installers (Console version)
 bin/7zSD.sfx     - SFX module for installers.


 7zDec.exe
 ---------
 7zDec.exe is simplified 7z archive decoder.
 It supports only LZMA, LZMA2, and PPMd methods.
 7zDec decodes whole solid block from 7z archive to RAM.
 The RAM consumption can be high.


 Source code structure
 ---------------------


 Asm/ - asm files (optimized code for CRC calculation and Intel-AES encryption)

 C/  - C files (compression / decompression and other)
   Util/
     7z       - 7z decoder program (decoding 7z files)
     Lzma     - LZMA program (file->file LZMA encoder/decoder).
     LzmaLib  - LZMA library (.DLL for Windows)
     SfxSetup - small SFX module for installers

 CPP/ -- CPP files

   Common  - common files for C++ projects
   Windows - common files for Windows related code

   7zip    - files related to 7-Zip

     Archive - files related to archiving

       Common   - common files for archive handling
       7z       - 7z C++ Encoder/Decoder

     Bundles  - Modules that are bundles of other modules (files)

       Alone7z       - 7zr.exe: Standalone 7-Zip console program (reduced version)
       Format7zExtractR  - 7zxr.dll: Reduced version of 7z DLL: extracting from 7z/LZMA/BCJ/BCJ2.
       Format7zR         - 7zr.dll:  Reduced version of 7z DLL: extracting/compressing to 7z/LZMA/BCJ/BCJ2
       LzmaCon       - lzma.exe: LZMA compression/decompression
       LzmaSpec      - example code for LZMA Specification
       SFXCon        - 7zCon.sfx: Console 7z SFX module
       SFXSetup      - 7zS.sfx: 7z SFX module for installers
       SFXWin        - 7z.sfx: GUI 7z SFX module

     Common   - common files for 7-Zip

     Compress - files for compression/decompression

     Crypto   - files for encryption / decompression

     UI       - User Interface files

       Client7z - Test application for 7za.dll, 7zr.dll, 7zxr.dll
       Common   - Common UI files
       Console  - Code for console program (7z.exe)
       Explorer    - Some code from 7-Zip Shell extension
       FileManager - Some GUI code from 7-Zip File Manager
       GUI         - Some GUI code from 7-Zip


 CS/ - C# files
   7zip
     Common   - some common files for 7-Zip
     Compress - files related to compression/decompression
       LZ     - files related to LZ (Lempel-Ziv) compression algorithm
       LZMA         - LZMA compression/decompression
       LzmaAlone    - file->file LZMA compression/decompression
       RangeCoder   - Range Coder (special code of compression/decompression)

 Java/  - Java files
   SevenZip
     Compression    - files related to compression/decompression
       LZ           - files related to LZ (Lempel-Ziv) compression algorithm
       LZMA         - LZMA compression/decompression
       RangeCoder   - Range Coder (special code of compression/decompression)


 Note:
   Asm / C / C++ source code of LZMA SDK is part of 7-Zip's source code.
   7-Zip's source code can be downloaded from 7-Zip's SourceForge page:

   http://sourceforge.net/projects/sevenzip/


 LZMA features
 -------------
   - Variable dictionary size (up to 1 GB)
   - Estimated compressing speed: about 2 MB/s on 2 GHz CPU
   - Estimated decompressing speed:
       - 20-30 MB/s on modern 2 GHz cpu
       - 1-2 MB/s on 200 MHz simple RISC cpu: (ARM, MIPS, PowerPC)
   - Small memory requirements for decompressing (16 KB + DictionarySize)
   - Small code size for decompressing: 5-8 KB

 LZMA decoder uses only integer operations and can be
 implemented in any modern 32-bit CPU (or on 16-bit CPU with some conditions).

 Some critical operations that affect the speed of LZMA decompression:
   1) 32*16 bit integer multiply
   2) Mispredicted branches (penalty mostly depends from pipeline length)
   3) 32-bit shift and arithmetic operations

 The speed of LZMA decompressing mostly depends from CPU speed.
 Memory speed has no big meaning. But if your CPU has small data cache,
 overall weight of memory speed will slightly increase.


 How To Use
 ----------

 Using LZMA encoder/decoder executable
 --------------------------------------

 Usage:  LZMA <e|d> inputFile outputFile [<switches>...]

   e: encode file

   d: decode file

   b: Benchmark. There are two tests: compressing and decompressing
      with LZMA method. Benchmark shows rating in MIPS (million
      instructions per second). Rating value is calculated from
      measured speed and it is normalized with Intel's Core 2 results.
      Also Benchmark checks possible hardware errors (RAM
      errors in most cases). Benchmark uses these settings:
      (-a1, -d21, -fb32, -mfbt4). You can change only -d parameter.
      Also you can change the number of iterations. Example for 30 iterations:
        LZMA b 30
      Default number of iterations is 10.

 <Switches>


   -a{N}:  set compression mode 0 = fast, 1 = normal
           default: 1 (normal)

   d{N}:   Sets Dictionary size - [0, 30], default: 23 (8MB)
           The maximum value for dictionary size is 1 GB = 2^30 bytes.
           Dictionary size is calculated as DictionarySize = 2^N bytes.
           For decompressing file compressed by LZMA method with dictionary
           size D = 2^N you need about D bytes of memory (RAM).

   -fb{N}: set number of fast bytes - [5, 273], default: 128
           Usually big number gives a little bit better compression ratio
           and slower compression process.

   -lc{N}: set number of literal context bits - [0, 8], default: 3
           Sometimes lc=4 gives gain for big files.

   -lp{N}: set number of literal pos bits - [0, 4], default: 0
           lp switch is intended for periodical data when period is
           equal 2^N. For example, for 32-bit (4 bytes)
           periodical data you can use lp=2. Often it's better to set lc0,
           if you change lp switch.

   -pb{N}: set number of pos bits - [0, 4], default: 2
           pb switch is intended for periodical data
           when period is equal 2^N.

   -mf{MF_ID}: set Match Finder. Default: bt4.
               Algorithms from hc* group doesn't provide good compression
               ratio, but they often works pretty fast in combination with
               fast mode (-a0).

               Memory requirements depend from dictionary size
               (parameter "d" in table below).

                MF_ID     Memory                   Description

                 bt2    d *  9.5 + 4MB  Binary Tree with 2 bytes hashing.
                 bt3    d * 11.5 + 4MB  Binary Tree with 3 bytes hashing.
                 bt4    d * 11.5 + 4MB  Binary Tree with 4 bytes hashing.
                 hc4    d *  7.5 + 4MB  Hash Chain with 4 bytes hashing.

   -eos:   write End Of Stream marker. By default LZMA doesn't write
           eos marker, since LZMA decoder knows uncompressed size
           stored in .lzma file header.

   -si:    Read data from stdin (it will write End Of Stream marker).
   -so:    Write data to stdout


 Examples:

 1) LZMA e file.bin file.lzma -d16 -lc0

 compresses file.bin to file.lzma with 64 KB dictionary (2^16=64K)
 and 0 literal context bits. -lc0 allows to reduce memory requirements
 for decompression.


 2) LZMA e file.bin file.lzma -lc0 -lp2

 compresses file.bin to file.lzma with settings suitable
 for 32-bit periodical data (for example, ARM or MIPS code).

 3) LZMA d file.lzma file.bin

 decompresses file.lzma to file.bin.


 Compression ratio hints
 -----------------------

 Recommendations
 ---------------

 To increase the compression ratio for LZMA compressing it's desirable
 to have aligned data (if it's possible) and also it's desirable to locate
 data in such order, where code is grouped in one place and data is
 grouped in other place (it's better than such mixing: code, data, code,
 data, ...).


 Filters
 -------
 You can increase the compression ratio for some data types, using
 special filters before compressing. For example, it's possible to
 increase the compression ratio on 5-10% for code for those CPU ISAs:
 x86, IA-64, ARM, ARM-Thumb, PowerPC, SPARC.

 You can find C source code of such filters in C/Bra*.* files

 You can check the compression ratio gain of these filters with such
 7-Zip commands (example for ARM code):
 No filter:
   7z a a1.7z a.bin -m0=lzma

 With filter for little-endian ARM code:
   7z a a2.7z a.bin -m0=arm -m1=lzma

 It works in such manner:
 Compressing    = Filter_encoding + LZMA_encoding
 Decompressing  = LZMA_decoding + Filter_decoding

 Compressing and decompressing speed of such filters is very high,
 so it will not increase decompressing time too much.
 Moreover, it reduces decompression time for LZMA_decoding,
 since compression ratio with filtering is higher.

 These filters convert CALL (calling procedure) instructions
 from relative offsets to absolute addresses, so such data becomes more
 compressible.

 For some ISAs (for example, for MIPS) it's impossible to get gain from such filter.


 ---

 http://www.7-zip.org
 http://www.7-zip.org/sdk.html
 http://www.7-zip.org/support.html
	LZMA SDK 16.04
	--------------

	LZMA SDK provides the documentation, samples, header files,
	libraries, and tools you need to develop applications that
	use 7z / LZMA / LZMA2 / XZ compression.

	LZMA is an improved version of famous LZ77 compression algorithm.
	It was improved in way of maximum increasing of compression ratio,
	keeping high decompression speed and low memory requirements for
	decompressing.

	LZMA2 is a LZMA based compression method. LZMA2 provides better
	multithreading support for compression than LZMA and some other improvements.

	7z is a file format for data compression and file archiving.
	7z is a main file format for 7-Zip compression program (www.7-zip.org).
	7z format supports different compression methods: LZMA, LZMA2 and others.
	7z also supports AES-256 based encryption.

	XZ is a file format for data compression that uses LZMA2 compression.
	XZ format provides additional features: SHA/CRC check, filters for
	improved compression ratio, splitting to blocks and streams,



	LICENSE
	-------

	LZMA SDK is written and placed in the public domain by Igor Pavlov.

	Some code in LZMA SDK is based on public domain code from another developers:
	1) PPMd var.H (2001): Dmitry Shkarin
	2) SHA-256: Wei Dai (Crypto++ library)

	Anyone is free to copy, modify, publish, use, compile, sell, or distribute the
	original LZMA SDK code, either in source code form or as a compiled binary, for
	any purpose, commercial or non-commercial, and by any means.

	LZMA SDK code is compatible with open source licenses, for example, you can
	include it to GNU GPL or GNU LGPL code.


	LZMA SDK Contents
	-----------------

	Source code:

	- C / C++ / C# / Java - LZMA compression and decompression
	- C / C++ - LZMA2 compression and decompression
	- C / C++ - XZ compression and decompression
	- C - 7z decompression
	- C++ - 7z compression and decompression
	- C - small SFXs for installers (7z decompression)
	- C++ - SFXs and SFXs for installers (7z decompression)

	Precomiled binaries:

	- console programs for lzma / 7z / xz compression and decompression
	- SFX modules for installers.


	UNIX/Linux version
	------------------
	To compile C++ version of file->file LZMA encoding, go to directory
	CPP/7zip/Bundles/LzmaCon
	and call make to recompile it:
	make -f makefile.gcc clean all

	In some UNIX/Linux versions you must compile LZMA with static libraries.
	To compile with static libraries, you can use
	LIB = -lm -static

	Also you can use p7zip (port of 7-Zip for POSIX systems like Unix or Linux):

	http://p7zip.sourceforge.net/


	Files
	-----

	DOC/7zC.txt - 7z ANSI-C Decoder description
	DOC/7zFormat.txt - 7z Format description
	DOC/installer.txt - information about 7-Zip for installers
	DOC/lzma.txt - LZMA compression description
	DOC/lzma-sdk.txt - LZMA SDK description (this file)
	DOC/lzma-history.txt - history of LZMA SDK
	DOC/lzma-specification.txt - Specification of LZMA
	DOC/Methods.txt - Compression method IDs for .7z

	bin/installer/ - example script to create installer that uses SFX module,

	bin/7zdec.exe - simplified 7z archive decoder
	bin/7zr.exe - 7-Zip console program (reduced version)
	bin/x64/7zr.exe - 7-Zip console program (reduced version) (x64 version)
	bin/lzma.exe - file->file LZMA encoder/decoder for Windows
	bin/7zS2.sfx - small SFX module for installers (GUI version)
	bin/7zS2con.sfx - small SFX module for installers (Console version)
	bin/7zSD.sfx - SFX module for installers.


	7zDec.exe
	---------
	7zDec.exe is simplified 7z archive decoder.
	It supports only LZMA, LZMA2, and PPMd methods.
	7zDec decodes whole solid block from 7z archive to RAM.
	The RAM consumption can be high.




	Source code structure
	---------------------


	Asm/ - asm files (optimized code for CRC calculation and Intel-AES encryption)

	C/ - C files (compression / decompression and other)
	Util/
	7z - 7z decoder program (decoding 7z files)
	Lzma - LZMA program (file->file LZMA encoder/decoder).
	LzmaLib - LZMA library (.DLL for Windows)
	SfxSetup - small SFX module for installers

	CPP/ -- CPP files

	Common - common files for C++ projects
	Windows - common files for Windows related code

	7zip - files related to 7-Zip

	Archive - files related to archiving

	Common - common files for archive handling
	7z - 7z C++ Encoder/Decoder

	Bundles - Modules that are bundles of other modules (files)

	Alone7z - 7zr.exe: Standalone 7-Zip console program (reduced version)
	Format7zExtractR - 7zxr.dll: Reduced version of 7z DLL: extracting from 7z/LZMA/BCJ/BCJ2.
	Format7zR - 7zr.dll: Reduced version of 7z DLL: extracting/compressing to 7z/LZMA/BCJ/BCJ2
	LzmaCon - lzma.exe: LZMA compression/decompression
	LzmaSpec - example code for LZMA Specification
	SFXCon - 7zCon.sfx: Console 7z SFX module
	SFXSetup - 7zS.sfx: 7z SFX module for installers
	SFXWin - 7z.sfx: GUI 7z SFX module

	Common - common files for 7-Zip

	Compress - files for compression/decompression

	Crypto - files for encryption / decompression

	UI - User Interface files

	Client7z - Test application for 7za.dll, 7zr.dll, 7zxr.dll
	Common - Common UI files
	Console - Code for console program (7z.exe)
	Explorer - Some code from 7-Zip Shell extension
	FileManager - Some GUI code from 7-Zip File Manager
	GUI - Some GUI code from 7-Zip


	CS/ - C# files
	7zip
	Common - some common files for 7-Zip
	Compress - files related to compression/decompression
	LZ - files related to LZ (Lempel-Ziv) compression algorithm
	LZMA - LZMA compression/decompression
	LzmaAlone - file->file LZMA compression/decompression
	RangeCoder - Range Coder (special code of compression/decompression)

	Java/ - Java files
	SevenZip
	Compression - files related to compression/decompression
	LZ - files related to LZ (Lempel-Ziv) compression algorithm
	LZMA - LZMA compression/decompression
	RangeCoder - Range Coder (special code of compression/decompression)


	Note:
	Asm / C / C++ source code of LZMA SDK is part of 7-Zip's source code.
	7-Zip's source code can be downloaded from 7-Zip's SourceForge page:

	http://sourceforge.net/projects/sevenzip/



	LZMA features
	-------------
	- Variable dictionary size (up to 1 GB)
	- Estimated compressing speed: about 2 MB/s on 2 GHz CPU
	- Estimated decompressing speed:
	- 20-30 MB/s on modern 2 GHz cpu
	- 1-2 MB/s on 200 MHz simple RISC cpu: (ARM, MIPS, PowerPC)
	- Small memory requirements for decompressing (16 KB + DictionarySize)
	- Small code size for decompressing: 5-8 KB

	LZMA decoder uses only integer operations and can be
	implemented in any modern 32-bit CPU (or on 16-bit CPU with some conditions).

	Some critical operations that affect the speed of LZMA decompression:
	1) 32*16 bit integer multiply
	2) Mispredicted branches (penalty mostly depends from pipeline length)
	3) 32-bit shift and arithmetic operations

	The speed of LZMA decompressing mostly depends from CPU speed.
	Memory speed has no big meaning. But if your CPU has small data cache,
	overall weight of memory speed will slightly increase.


	How To Use
	----------

	Using LZMA encoder/decoder executable
	--------------------------------------

	Usage: LZMA <e\|d> inputFile outputFile [<switches>...]

	e: encode file

	d: decode file

	b: Benchmark. There are two tests: compressing and decompressing
	with LZMA method. Benchmark shows rating in MIPS (million
	instructions per second). Rating value is calculated from
	measured speed and it is normalized with Intel's Core 2 results.
	Also Benchmark checks possible hardware errors (RAM
	errors in most cases). Benchmark uses these settings:
	(-a1, -d21, -fb32, -mfbt4). You can change only -d parameter.
	Also you can change the number of iterations. Example for 30 iterations:
	LZMA b 30
	Default number of iterations is 10.

	<Switches>


	-a{N}: set compression mode 0 = fast, 1 = normal
	default: 1 (normal)

	d{N}: Sets Dictionary size - [0, 30], default: 23 (8MB)
	The maximum value for dictionary size is 1 GB = 2^30 bytes.
	Dictionary size is calculated as DictionarySize = 2^N bytes.
	For decompressing file compressed by LZMA method with dictionary
	size D = 2^N you need about D bytes of memory (RAM).

	-fb{N}: set number of fast bytes - [5, 273], default: 128
	Usually big number gives a little bit better compression ratio
	and slower compression process.

	-lc{N}: set number of literal context bits - [0, 8], default: 3
	Sometimes lc=4 gives gain for big files.

	-lp{N}: set number of literal pos bits - [0, 4], default: 0
	lp switch is intended for periodical data when period is
	equal 2^N. For example, for 32-bit (4 bytes)
	periodical data you can use lp=2. Often it's better to set lc0,
	if you change lp switch.

	-pb{N}: set number of pos bits - [0, 4], default: 2
	pb switch is intended for periodical data
	when period is equal 2^N.

	-mf{MF_ID}: set Match Finder. Default: bt4.
	Algorithms from hc* group doesn't provide good compression
	ratio, but they often works pretty fast in combination with
	fast mode (-a0).

	Memory requirements depend from dictionary size
	(parameter "d" in table below).

	MF_ID Memory Description

	bt2 d * 9.5 + 4MB Binary Tree with 2 bytes hashing.
	bt3 d * 11.5 + 4MB Binary Tree with 3 bytes hashing.
	bt4 d * 11.5 + 4MB Binary Tree with 4 bytes hashing.
	hc4 d * 7.5 + 4MB Hash Chain with 4 bytes hashing.

	-eos: write End Of Stream marker. By default LZMA doesn't write
	eos marker, since LZMA decoder knows uncompressed size
	stored in .lzma file header.

	-si: Read data from stdin (it will write End Of Stream marker).
	-so: Write data to stdout


	Examples:

	1) LZMA e file.bin file.lzma -d16 -lc0

	compresses file.bin to file.lzma with 64 KB dictionary (2^16=64K)
	and 0 literal context bits. -lc0 allows to reduce memory requirements
	for decompression.


	2) LZMA e file.bin file.lzma -lc0 -lp2

	compresses file.bin to file.lzma with settings suitable
	for 32-bit periodical data (for example, ARM or MIPS code).

	3) LZMA d file.lzma file.bin

	decompresses file.lzma to file.bin.


	Compression ratio hints
	-----------------------

	Recommendations
	---------------

	To increase the compression ratio for LZMA compressing it's desirable
	to have aligned data (if it's possible) and also it's desirable to locate
	data in such order, where code is grouped in one place and data is
	grouped in other place (it's better than such mixing: code, data, code,
	data, ...).


	Filters
	-------
	You can increase the compression ratio for some data types, using
	special filters before compressing. For example, it's possible to
	increase the compression ratio on 5-10% for code for those CPU ISAs:
	x86, IA-64, ARM, ARM-Thumb, PowerPC, SPARC.

	You can find C source code of such filters in C/Bra. files

	You can check the compression ratio gain of these filters with such
	7-Zip commands (example for ARM code):
	No filter:
	7z a a1.7z a.bin -m0=lzma

	With filter for little-endian ARM code:
	7z a a2.7z a.bin -m0=arm -m1=lzma

	It works in such manner:
	Compressing = Filter_encoding + LZMA_encoding
	Decompressing = LZMA_decoding + Filter_decoding

	Compressing and decompressing speed of such filters is very high,
	so it will not increase decompressing time too much.
	Moreover, it reduces decompression time for LZMA_decoding,
	since compression ratio with filtering is higher.

	These filters convert CALL (calling procedure) instructions
	from relative offsets to absolute addresses, so such data becomes more
	compressible.

	For some ISAs (for example, for MIPS) it's impossible to get gain from such filter.



	---

	http://www.7-zip.org
	http://www.7-zip.org/sdk.html
	http://www.7-zip.org/support.html