+++ /dev/null
-LZMA SDK 18.05\r
---------------\r
-\r
-LZMA SDK provides the documentation, samples, header files,\r
-libraries, and tools you need to develop applications that \r
-use 7z / LZMA / LZMA2 / XZ compression.\r
-\r
-LZMA is an improved version of famous LZ77 compression algorithm. \r
-It was improved in way of maximum increasing of compression ratio,\r
-keeping high decompression speed and low memory requirements for \r
-decompressing.\r
-\r
-LZMA2 is a LZMA based compression method. LZMA2 provides better \r
-multithreading support for compression than LZMA and some other improvements.\r
-\r
-7z is a file format for data compression and file archiving.\r
-7z is a main file format for 7-Zip compression program (www.7-zip.org).\r
-7z format supports different compression methods: LZMA, LZMA2 and others.\r
-7z also supports AES-256 based encryption.\r
-\r
-XZ is a file format for data compression that uses LZMA2 compression.\r
-XZ format provides additional features: SHA/CRC check, filters for \r
-improved compression ratio, splitting to blocks and streams,\r
-\r
-\r
-\r
-LICENSE\r
--------\r
-\r
-LZMA SDK is written and placed in the public domain by Igor Pavlov.\r
-\r
-Some code in LZMA SDK is based on public domain code from another developers:\r
- 1) PPMd var.H (2001): Dmitry Shkarin\r
- 2) SHA-256: Wei Dai (Crypto++ library)\r
-\r
-Anyone is free to copy, modify, publish, use, compile, sell, or distribute the \r
-original LZMA SDK code, either in source code form or as a compiled binary, for \r
-any purpose, commercial or non-commercial, and by any means.\r
-\r
-LZMA SDK code is compatible with open source licenses, for example, you can \r
-include it to GNU GPL or GNU LGPL code.\r
-\r
-\r
-LZMA SDK Contents\r
------------------\r
-\r
- Source code:\r
-\r
- - C / C++ / C# / Java - LZMA compression and decompression\r
- - C / C++ - LZMA2 compression and decompression\r
- - C / C++ - XZ compression and decompression\r
- - C - 7z decompression\r
- - C++ - 7z compression and decompression\r
- - C - small SFXs for installers (7z decompression)\r
- - C++ - SFXs and SFXs for installers (7z decompression)\r
-\r
- Precomiled binaries:\r
-\r
- - console programs for lzma / 7z / xz compression and decompression\r
- - SFX modules for installers.\r
-\r
-\r
-UNIX/Linux version \r
-------------------\r
-To compile C++ version of file->file LZMA encoding, go to directory\r
-CPP/7zip/Bundles/LzmaCon\r
-and call make to recompile it:\r
- make -f makefile.gcc clean all\r
-\r
-In some UNIX/Linux versions you must compile LZMA with static libraries.\r
-To compile with static libraries, you can use \r
-LIB = -lm -static\r
-\r
-Also you can use p7zip (port of 7-Zip for POSIX systems like Unix or Linux):\r
- \r
- http://p7zip.sourceforge.net/\r
-\r
-\r
-Files\r
------\r
-\r
-DOC/7zC.txt - 7z ANSI-C Decoder description\r
-DOC/7zFormat.txt - 7z Format description\r
-DOC/installer.txt - information about 7-Zip for installers\r
-DOC/lzma.txt - LZMA compression description\r
-DOC/lzma-sdk.txt - LZMA SDK description (this file)\r
-DOC/lzma-history.txt - history of LZMA SDK\r
-DOC/lzma-specification.txt - Specification of LZMA\r
-DOC/Methods.txt - Compression method IDs for .7z\r
-\r
-bin/installer/ - example script to create installer that uses SFX module,\r
-\r
-bin/7zdec.exe - simplified 7z archive decoder\r
-bin/7zr.exe - 7-Zip console program (reduced version)\r
-bin/x64/7zr.exe - 7-Zip console program (reduced version) (x64 version)\r
-bin/lzma.exe - file->file LZMA encoder/decoder for Windows\r
-bin/7zS2.sfx - small SFX module for installers (GUI version)\r
-bin/7zS2con.sfx - small SFX module for installers (Console version)\r
-bin/7zSD.sfx - SFX module for installers.\r
-\r
-\r
-7zDec.exe\r
----------\r
-7zDec.exe is simplified 7z archive decoder.\r
-It supports only LZMA, LZMA2, and PPMd methods.\r
-7zDec decodes whole solid block from 7z archive to RAM.\r
-The RAM consumption can be high.\r
-\r
-\r
-\r
-\r
-Source code structure\r
----------------------\r
-\r
-\r
-Asm/ - asm files (optimized code for CRC calculation and Intel-AES encryption)\r
-\r
-C/ - C files (compression / decompression and other)\r
- Util/\r
- 7z - 7z decoder program (decoding 7z files)\r
- Lzma - LZMA program (file->file LZMA encoder/decoder).\r
- LzmaLib - LZMA library (.DLL for Windows)\r
- SfxSetup - small SFX module for installers \r
-\r
-CPP/ -- CPP files\r
-\r
- Common - common files for C++ projects\r
- Windows - common files for Windows related code\r
-\r
- 7zip - files related to 7-Zip\r
-\r
- Archive - files related to archiving\r
-\r
- Common - common files for archive handling\r
- 7z - 7z C++ Encoder/Decoder\r
-\r
- Bundles - Modules that are bundles of other modules (files)\r
- \r
- Alone7z - 7zr.exe: Standalone 7-Zip console program (reduced version)\r
- Format7zExtractR - 7zxr.dll: Reduced version of 7z DLL: extracting from 7z/LZMA/BCJ/BCJ2.\r
- Format7zR - 7zr.dll: Reduced version of 7z DLL: extracting/compressing to 7z/LZMA/BCJ/BCJ2\r
- LzmaCon - lzma.exe: LZMA compression/decompression\r
- LzmaSpec - example code for LZMA Specification\r
- SFXCon - 7zCon.sfx: Console 7z SFX module\r
- SFXSetup - 7zS.sfx: 7z SFX module for installers\r
- SFXWin - 7z.sfx: GUI 7z SFX module\r
-\r
- Common - common files for 7-Zip\r
-\r
- Compress - files for compression/decompression\r
-\r
- Crypto - files for encryption / decompression\r
-\r
- UI - User Interface files\r
- \r
- Client7z - Test application for 7za.dll, 7zr.dll, 7zxr.dll\r
- Common - Common UI files\r
- Console - Code for console program (7z.exe)\r
- Explorer - Some code from 7-Zip Shell extension\r
- FileManager - Some GUI code from 7-Zip File Manager\r
- GUI - Some GUI code from 7-Zip\r
-\r
-\r
-CS/ - C# files\r
- 7zip\r
- Common - some common files for 7-Zip\r
- Compress - files related to compression/decompression\r
- LZ - files related to LZ (Lempel-Ziv) compression algorithm\r
- LZMA - LZMA compression/decompression\r
- LzmaAlone - file->file LZMA compression/decompression\r
- RangeCoder - Range Coder (special code of compression/decompression)\r
-\r
-Java/ - Java files\r
- SevenZip\r
- Compression - files related to compression/decompression\r
- LZ - files related to LZ (Lempel-Ziv) compression algorithm\r
- LZMA - LZMA compression/decompression\r
- RangeCoder - Range Coder (special code of compression/decompression)\r
-\r
-\r
-Note: \r
- Asm / C / C++ source code of LZMA SDK is part of 7-Zip's source code.\r
- 7-Zip's source code can be downloaded from 7-Zip's SourceForge page:\r
-\r
- http://sourceforge.net/projects/sevenzip/\r
-\r
-\r
-\r
-LZMA features\r
--------------\r
- - Variable dictionary size (up to 1 GB)\r
- - Estimated compressing speed: about 2 MB/s on 2 GHz CPU\r
- - Estimated decompressing speed: \r
- - 20-30 MB/s on modern 2 GHz cpu\r
- - 1-2 MB/s on 200 MHz simple RISC cpu: (ARM, MIPS, PowerPC)\r
- - Small memory requirements for decompressing (16 KB + DictionarySize)\r
- - Small code size for decompressing: 5-8 KB\r
-\r
-LZMA decoder uses only integer operations and can be \r
-implemented in any modern 32-bit CPU (or on 16-bit CPU with some conditions).\r
-\r
-Some critical operations that affect the speed of LZMA decompression:\r
- 1) 32*16 bit integer multiply\r
- 2) Mispredicted branches (penalty mostly depends from pipeline length)\r
- 3) 32-bit shift and arithmetic operations\r
-\r
-The speed of LZMA decompressing mostly depends from CPU speed.\r
-Memory speed has no big meaning. But if your CPU has small data cache, \r
-overall weight of memory speed will slightly increase.\r
-\r
-\r
-How To Use\r
-----------\r
-\r
-Using LZMA encoder/decoder executable\r
---------------------------------------\r
-\r
-Usage: LZMA <e|d> inputFile outputFile [<switches>...]\r
-\r
- e: encode file\r
-\r
- d: decode file\r
-\r
- b: Benchmark. There are two tests: compressing and decompressing \r
- with LZMA method. Benchmark shows rating in MIPS (million \r
- instructions per second). Rating value is calculated from \r
- measured speed and it is normalized with Intel's Core 2 results.\r
- Also Benchmark checks possible hardware errors (RAM \r
- errors in most cases). Benchmark uses these settings:\r
- (-a1, -d21, -fb32, -mfbt4). You can change only -d parameter. \r
- Also you can change the number of iterations. Example for 30 iterations:\r
- LZMA b 30\r
- Default number of iterations is 10.\r
-\r
-<Switches>\r
- \r
-\r
- -a{N}: set compression mode 0 = fast, 1 = normal\r
- default: 1 (normal)\r
-\r
- d{N}: Sets Dictionary size - [0, 30], default: 23 (8MB)\r
- The maximum value for dictionary size is 1 GB = 2^30 bytes.\r
- Dictionary size is calculated as DictionarySize = 2^N bytes. \r
- For decompressing file compressed by LZMA method with dictionary \r
- size D = 2^N you need about D bytes of memory (RAM).\r
-\r
- -fb{N}: set number of fast bytes - [5, 273], default: 128\r
- Usually big number gives a little bit better compression ratio \r
- and slower compression process.\r
-\r
- -lc{N}: set number of literal context bits - [0, 8], default: 3\r
- Sometimes lc=4 gives gain for big files.\r
-\r
- -lp{N}: set number of literal pos bits - [0, 4], default: 0\r
- lp switch is intended for periodical data when period is \r
- equal 2^N. For example, for 32-bit (4 bytes) \r
- periodical data you can use lp=2. Often it's better to set lc0, \r
- if you change lp switch.\r
-\r
- -pb{N}: set number of pos bits - [0, 4], default: 2\r
- pb switch is intended for periodical data \r
- when period is equal 2^N.\r
-\r
- -mf{MF_ID}: set Match Finder. Default: bt4. \r
- Algorithms from hc* group doesn't provide good compression \r
- ratio, but they often works pretty fast in combination with \r
- fast mode (-a0).\r
-\r
- Memory requirements depend from dictionary size \r
- (parameter "d" in table below). \r
-\r
- MF_ID Memory Description\r
-\r
- bt2 d * 9.5 + 4MB Binary Tree with 2 bytes hashing.\r
- bt3 d * 11.5 + 4MB Binary Tree with 3 bytes hashing.\r
- bt4 d * 11.5 + 4MB Binary Tree with 4 bytes hashing.\r
- hc4 d * 7.5 + 4MB Hash Chain with 4 bytes hashing.\r
-\r
- -eos: write End Of Stream marker. By default LZMA doesn't write \r
- eos marker, since LZMA decoder knows uncompressed size \r
- stored in .lzma file header.\r
-\r
- -si: Read data from stdin (it will write End Of Stream marker).\r
- -so: Write data to stdout\r
-\r
-\r
-Examples:\r
-\r
-1) LZMA e file.bin file.lzma -d16 -lc0 \r
-\r
-compresses file.bin to file.lzma with 64 KB dictionary (2^16=64K) \r
-and 0 literal context bits. -lc0 allows to reduce memory requirements \r
-for decompression.\r
-\r
-\r
-2) LZMA e file.bin file.lzma -lc0 -lp2\r
-\r
-compresses file.bin to file.lzma with settings suitable \r
-for 32-bit periodical data (for example, ARM or MIPS code).\r
-\r
-3) LZMA d file.lzma file.bin\r
-\r
-decompresses file.lzma to file.bin.\r
-\r
-\r
-Compression ratio hints\r
------------------------\r
-\r
-Recommendations\r
----------------\r
-\r
-To increase the compression ratio for LZMA compressing it's desirable \r
-to have aligned data (if it's possible) and also it's desirable to locate\r
-data in such order, where code is grouped in one place and data is \r
-grouped in other place (it's better than such mixing: code, data, code,\r
-data, ...).\r
-\r
-\r
-Filters\r
--------\r
-You can increase the compression ratio for some data types, using\r
-special filters before compressing. For example, it's possible to \r
-increase the compression ratio on 5-10% for code for those CPU ISAs: \r
-x86, IA-64, ARM, ARM-Thumb, PowerPC, SPARC.\r
-\r
-You can find C source code of such filters in C/Bra*.* files\r
-\r
-You can check the compression ratio gain of these filters with such \r
-7-Zip commands (example for ARM code):\r
-No filter:\r
- 7z a a1.7z a.bin -m0=lzma\r
-\r
-With filter for little-endian ARM code:\r
- 7z a a2.7z a.bin -m0=arm -m1=lzma \r
-\r
-It works in such manner:\r
-Compressing = Filter_encoding + LZMA_encoding\r
-Decompressing = LZMA_decoding + Filter_decoding\r
-\r
-Compressing and decompressing speed of such filters is very high,\r
-so it will not increase decompressing time too much.\r
-Moreover, it reduces decompression time for LZMA_decoding, \r
-since compression ratio with filtering is higher.\r
-\r
-These filters convert CALL (calling procedure) instructions \r
-from relative offsets to absolute addresses, so such data becomes more \r
-compressible.\r
-\r
-For some ISAs (for example, for MIPS) it's impossible to get gain from such filter.\r
-\r
-\r
-\r
----\r
-\r
-http://www.7-zip.org\r
-http://www.7-zip.org/sdk.html\r
-http://www.7-zip.org/support.html\r
projects / mirror_edk2.git / blobdiff