src/lzma/lzma.txt
changeset 972 254427fc42ab
parent 917 d299a58a274f
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/lzma/lzma.txt	Fri Mar 27 15:10:42 2009 -0400
@@ -0,0 +1,663 @@
+LZMA SDK 4.57
+-------------
+
+LZMA SDK   Copyright (C) 1999-2007 Igor Pavlov
+
+LZMA SDK provides the documentation, samples, header files, libraries, 
+and tools you need to develop applications that use LZMA compression.
+
+LZMA is default and general compression method of 7z format
+in 7-Zip compression program (www.7-zip.org). LZMA provides high 
+compression ratio and very fast decompression.
+
+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.
+
+
+
+LICENSE
+-------
+
+LZMA SDK is available under any of the following licenses:
+
+1) GNU Lesser General Public License (GNU LGPL)
+2) Common Public License (CPL)
+3) Simplified license for unmodified code (read SPECIAL EXCEPTION) 
+4) Proprietary license 
+
+It means that you can select one of these four options and follow rules of that license.
+
+
+1,2) GNU LGPL and CPL licenses are pretty similar and both these
+licenses are classified as 
+ - "Free software licenses" at http://www.gnu.org/ 
+ - "OSI-approved" at http://www.opensource.org/
+
+
+3) SPECIAL EXCEPTION
+
+Igor Pavlov, as the author of this code, expressly permits you 
+to statically or dynamically link your code (or bind by name) 
+to the files from LZMA SDK without subjecting your linked 
+code to the terms of the CPL or GNU LGPL. 
+Any modifications or additions to files from LZMA SDK, however, 
+are subject to the GNU LGPL or CPL terms.
+
+SPECIAL EXCEPTION allows you to use LZMA SDK in applications with closed code, 
+while you keep LZMA SDK code unmodified.
+
+
+SPECIAL EXCEPTION #2: Igor Pavlov, as the author of this code, expressly permits 
+you to use this code under the same terms and conditions contained in the License 
+Agreement you have for any previous version of LZMA SDK developed by Igor Pavlov.
+
+SPECIAL EXCEPTION #2 allows owners of proprietary licenses to use latest version 
+of LZMA SDK as update for previous versions.
+
+
+SPECIAL EXCEPTION #3: Igor Pavlov, as the author of this code, expressly permits 
+you to use code of the following files: 
+BranchTypes.h, LzmaTypes.h, LzmaTest.c, LzmaStateTest.c, LzmaAlone.cpp, 
+LzmaAlone.cs, LzmaAlone.java
+as public domain code. 
+
+
+4) Proprietary license
+
+LZMA SDK also can be available under a proprietary license which 
+can include:
+
+1) Right to modify code without subjecting modified code to the 
+terms of the CPL or GNU LGPL
+2) Technical support for code
+
+To request such proprietary license or any additional consultations,
+send email message from that page:
+http://www.7-zip.org/support.html
+
+
+You should have received a copy of the GNU Lesser General Public
+License along with this library; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+You should have received a copy of the Common Public License
+along with this library.
+
+
+LZMA SDK Contents
+-----------------
+
+LZMA SDK includes:
+
+  - C++ source code of LZMA compressing and decompressing
+  - ANSI-C compatible source code for LZMA decompressing
+  - C# source code for LZMA compressing and decompressing
+  - Java source code for LZMA compressing and decompressing
+  - Compiled file->file LZMA compressing/decompressing program for Windows system
+
+ANSI-C LZMA decompression code was ported from original C++ sources to C.
+Also it was simplified and optimized for code size. 
+But it is fully compatible with LZMA from 7-Zip.
+
+
+UNIX/Linux version 
+------------------
+To compile C++ version of file->file LZMA, go to directory
+C/7zip/Compress/LZMA_Alone 
+and type "make" or "make clean all" to recompile all.
+
+In some UNIX/Linux versions you must compile LZMA with static libraries.
+To compile with static libraries, change string in makefile
+LIB = -lm
+to string  
+LIB = -lm -static
+
+
+Files
+---------------------
+C        - C source code
+CPP      - CPP source code
+CS       - C# source code
+Java     - Java source code
+lzma.txt - LZMA SDK description (this file)
+7zFormat.txt - 7z Format description
+7zC.txt  - 7z ANSI-C Decoder description (this file)
+methods.txt  - Compression method IDs for .7z
+LGPL.txt - GNU Lesser General Public License
+CPL.html - Common Public License
+lzma.exe - Compiled file->file LZMA encoder/decoder for Windows
+history.txt - history of the LZMA SDK
+
+
+Source code structure
+---------------------
+
+C  - C files
+    Compress - files related to compression/decompression
+      Lz     - files related to LZ (Lempel-Ziv) compression algorithm
+      Lzma   - ANSI-C compatible LZMA decompressor
+
+        LzmaDecode.h  - interface for LZMA decoding on ANSI-C
+        LzmaDecode.c      - LZMA decoding on ANSI-C (new fastest version)
+        LzmaDecodeSize.c  - LZMA decoding on ANSI-C (old size-optimized version)
+        LzmaTest.c        - test application that decodes LZMA encoded file
+        LzmaTypes.h       - basic types for LZMA Decoder
+        LzmaStateDecode.h - interface for LZMA decoding (State version)
+        LzmaStateDecode.c - LZMA decoding on ANSI-C (State version)
+        LzmaStateTest.c   - test application (State version)
+
+      Branch       - Filters for x86, IA-64, ARM, ARM-Thumb, PowerPC and SPARC code
+
+    Archive - files related to archiving
+      7z_C     - 7z ANSI-C Decoder
+
+
+CPP -- CPP files
+
+  Common  - common files for C++ projects
+  Windows - common files for Windows related code
+  7zip    - files related to 7-Zip Project
+
+    Common   - common files for 7-Zip
+
+    Compress - files related to compression/decompression
+
+      LZ     - files related to LZ (Lempel-Ziv) compression algorithm
+
+      Copy         - Copy coder
+      RangeCoder   - Range Coder (special code of compression/decompression)
+      LZMA         - LZMA compression/decompression on C++
+      LZMA_Alone   - file->file LZMA compression/decompression
+
+      Branch       - Filters for x86, IA-64, ARM, ARM-Thumb, PowerPC and SPARC code
+
+    Archive - files related to archiving
+
+      Common   - common files for archive handling
+      7z       - 7z C++ Encoder/Decoder
+
+    Bundles    - Modules that are bundles of other modules
+  
+      Alone7z           - 7zr.exe: Standalone version of 7z.exe that supports only 7z/LZMA/BCJ/BCJ2
+      Format7zR         - 7zr.dll: Reduced version of 7za.dll: extracting/compressing to 7z/LZMA/BCJ/BCJ2
+      Format7zExtractR  - 7zxr.dll: Reduced version of 7zxa.dll: extracting from 7z/LZMA/BCJ/BCJ2.
+
+    UI        - User Interface files
+         
+      Client7z - Test application for 7za.dll,  7zr.dll, 7zxr.dll
+      Common   - Common UI files
+      Console  - Code for console archiver
+
+
+
+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)
+
+C/C++ source code of LZMA SDK is part of 7-Zip project.
+
+You can find ANSI-C LZMA decompressing code at folder 
+  C/7zip/Compress/Lzma
+7-Zip doesn't use that ANSI-C LZMA code and that code was developed 
+specially for this SDK. And files from C/7zip/Compress/Lzma do not need 
+files from other directories of SDK for compiling.
+
+7-Zip 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 1 MB/s on 1 GHz CPU
+  - Estimated decompressing speed: 
+      - 8-12 MB/s on 1 GHz Intel Pentium 3 or AMD Athlon
+      - 500-1000 KB/s on 100 MHz ARM, MIPS, PowerPC or other simple RISC
+  - Small memory requirements for decompressing (8-32 KB + DictionarySize)
+  - Small code size for decompressing: 2-8 KB (depending from 
+    speed optimizations) 
+
+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 to speed of LZMA decompression:
+  1) 32*16 bit integer multiply
+  2) Misspredicted branches (penalty mostly depends from pipeline length)
+  3) 32-bit shift and arithmetic operations
+
+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 AMD Athlon 64 X2 CPU
+     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. Also you 
+     can change 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 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, ...).
+
+
+Using Filters
+-------------
+You can increase compression ratio for some data types, using
+special filters before compressing. For example, it's possible to 
+increase compression ratio on 5-10% for code for those CPU ISAs: 
+x86, IA-64, ARM, ARM-Thumb, PowerPC, SPARC.
+
+You can find C/C++ source code of such filters in folder "7zip/Compress/Branch"
+
+You can check 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=bc_arm -m1=lzma        
+
+With filter for big-endian ARM code (using additional Swap4 filter):
+  7z a a3.7z a.bin -m0=swap4 -m1=bc_arm -m2=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. Source code of these CALL filters is pretty simple
+(about 20 lines of C++), so you can convert it from C++ version yourself.
+
+For some ISAs (for example, for MIPS) it's impossible to get gain from such filter.
+
+
+LZMA compressed file format
+---------------------------
+Offset Size Description
+  0     1   Special LZMA properties for compressed data
+  1     4   Dictionary size (little endian)
+  5     8   Uncompressed size (little endian). -1 means unknown size
+ 13         Compressed data
+
+
+ANSI-C LZMA Decoder
+~~~~~~~~~~~~~~~~~~~
+
+To compile ANSI-C LZMA Decoder you can use one of the following files sets:
+1) LzmaDecode.h + LzmaDecode.c + LzmaTest.c  (fastest version)
+2) LzmaDecode.h + LzmaDecodeSize.c + LzmaTest.c  (old size-optimized version)
+3) LzmaStateDecode.h + LzmaStateDecode.c + LzmaStateTest.c  (zlib-like interface)
+
+
+Memory requirements for LZMA decoding
+-------------------------------------
+
+LZMA decoder doesn't allocate memory itself, so you must 
+allocate memory and send it to LZMA.
+
+Stack usage of LZMA decoding function for local variables is not 
+larger than 200 bytes.
+
+How To decompress data
+----------------------
+
+LZMA Decoder (ANSI-C version) now supports 5 interfaces:
+1) Single-call Decompressing
+2) Single-call Decompressing with input stream callback
+3) Multi-call Decompressing with output buffer
+4) Multi-call Decompressing with input callback and output buffer
+5) Multi-call State Decompressing (zlib-like interface)
+
+Variant-5 is similar to Variant-4, but Variant-5 doesn't use callback functions.
+
+Decompressing steps
+-------------------
+
+1) read LZMA properties (5 bytes):
+   unsigned char properties[LZMA_PROPERTIES_SIZE];
+
+2) read uncompressed size (8 bytes, little-endian)
+
+3) Decode properties:
+
+  CLzmaDecoderState state;  /* it's 24-140 bytes structure, if int is 32-bit */
+
+  if (LzmaDecodeProperties(&state.Properties, properties, LZMA_PROPERTIES_SIZE) != LZMA_RESULT_OK)
+    return PrintError(rs, "Incorrect stream properties");
+
+4) Allocate memory block for internal Structures:
+
+  state.Probs = (CProb *)malloc(LzmaGetNumProbs(&state.Properties) * sizeof(CProb));
+  if (state.Probs == 0)
+    return PrintError(rs, kCantAllocateMessage);
+
+  LZMA decoder uses array of CProb variables as internal structure.
+  By default, CProb is unsigned_short. But you can define _LZMA_PROB32 to make 
+  it unsigned_int. It can increase speed on some 32-bit CPUs, but memory 
+  usage will be doubled in that case.
+
+
+5) Main Decompressing
+
+You must use one of the following interfaces:
+
+5.1 Single-call Decompressing
+-----------------------------
+When to use: RAM->RAM decompressing
+Compile files: LzmaDecode.h, LzmaDecode.c
+Compile defines: no defines
+Memory Requirements:
+  - Input buffer: compressed size
+  - Output buffer: uncompressed size
+  - LZMA Internal Structures (~16 KB for default settings) 
+
+Interface:
+  int res = LzmaDecode(&state, 
+      inStream, compressedSize, &inProcessed,
+      outStream, outSize, &outProcessed);
+
+
+5.2 Single-call Decompressing with input stream callback
+--------------------------------------------------------
+When to use: File->RAM or Flash->RAM decompressing.
+Compile files: LzmaDecode.h, LzmaDecode.c
+Compile defines: _LZMA_IN_CB
+Memory Requirements:
+  - Buffer for input stream: any size (for example, 16 KB)
+  - Output buffer: uncompressed size
+  - LZMA Internal Structures (~16 KB for default settings) 
+
+Interface:
+  typedef struct _CBuffer
+  {
+    ILzmaInCallback InCallback;
+    FILE *File;
+    unsigned char Buffer[kInBufferSize];
+  } CBuffer;
+
+  int LzmaReadCompressed(void *object, const unsigned char **buffer, SizeT *size)
+  {
+    CBuffer *bo = (CBuffer *)object;
+    *buffer = bo->Buffer;
+    *size = MyReadFile(bo->File, bo->Buffer, kInBufferSize);
+    return LZMA_RESULT_OK;
+  }
+
+  CBuffer g_InBuffer;
+
+  g_InBuffer.File = inFile;
+  g_InBuffer.InCallback.Read = LzmaReadCompressed;
+  int res = LzmaDecode(&state, 
+      &g_InBuffer.InCallback,
+      outStream, outSize, &outProcessed);
+
+
+5.3 Multi-call decompressing with output buffer
+-----------------------------------------------
+When to use: RAM->File decompressing 
+Compile files: LzmaDecode.h, LzmaDecode.c
+Compile defines: _LZMA_OUT_READ
+Memory Requirements:
+ - Input buffer: compressed size
+ - Buffer for output stream: any size (for example, 16 KB)
+ - LZMA Internal Structures (~16 KB for default settings) 
+ - LZMA dictionary (dictionary size is encoded in stream properties)
+ 
+Interface:
+
+  state.Dictionary = (unsigned char *)malloc(state.Properties.DictionarySize);
+
+  LzmaDecoderInit(&state);
+  do
+  {
+    LzmaDecode(&state,
+      inBuffer, inAvail, &inProcessed,
+      g_OutBuffer, outAvail, &outProcessed);
+    inAvail -= inProcessed;
+    inBuffer += inProcessed;
+  }
+  while you need more bytes
+
+  see LzmaTest.c for more details.
+
+
+5.4 Multi-call decompressing with input callback and output buffer
+------------------------------------------------------------------
+When to use: File->File decompressing 
+Compile files: LzmaDecode.h, LzmaDecode.c
+Compile defines: _LZMA_IN_CB, _LZMA_OUT_READ
+Memory Requirements:
+ - Buffer for input stream: any size (for example, 16 KB)
+ - Buffer for output stream: any size (for example, 16 KB)
+ - LZMA Internal Structures (~16 KB for default settings) 
+ - LZMA dictionary (dictionary size is encoded in stream properties)
+ 
+Interface:
+
+  state.Dictionary = (unsigned char *)malloc(state.Properties.DictionarySize);
+ 
+  LzmaDecoderInit(&state);
+  do
+  {
+    LzmaDecode(&state,
+      &bo.InCallback,
+      g_OutBuffer, outAvail, &outProcessed);
+  }
+  while you need more bytes
+
+  see LzmaTest.c for more details:
+
+
+5.5 Multi-call State Decompressing (zlib-like interface)
+------------------------------------------------------------------
+When to use: file->file decompressing 
+Compile files: LzmaStateDecode.h, LzmaStateDecode.c
+Compile defines:
+Memory Requirements:
+ - Buffer for input stream: any size (for example, 16 KB)
+ - Buffer for output stream: any size (for example, 16 KB)
+ - LZMA Internal Structures (~16 KB for default settings) 
+ - LZMA dictionary (dictionary size is encoded in stream properties)
+ 
+Interface:
+
+  state.Dictionary = (unsigned char *)malloc(state.Properties.DictionarySize);
+
+  
+  LzmaDecoderInit(&state);
+  do
+  {
+    res = LzmaDecode(&state,
+      inBuffer, inAvail, &inProcessed,
+      g_OutBuffer, outAvail, &outProcessed,
+      finishDecoding);
+    inAvail -= inProcessed;
+    inBuffer += inProcessed;
+  }
+  while you need more bytes
+
+  see LzmaStateTest.c for more details:
+
+
+6) Free all allocated blocks
+
+
+Note
+----
+LzmaDecodeSize.c is size-optimized version of LzmaDecode.c.
+But compiled code of LzmaDecodeSize.c can be larger than 
+compiled code of LzmaDecode.c. So it's better to use 
+LzmaDecode.c in most cases.
+
+
+EXIT codes
+-----------
+
+LZMA decoder can return one of the following codes:
+
+#define LZMA_RESULT_OK 0
+#define LZMA_RESULT_DATA_ERROR 1
+
+If you use callback function for input data and you return some 
+error code, LZMA Decoder also returns that code.
+
+
+
+LZMA Defines
+------------
+
+_LZMA_IN_CB    - Use callback for input data
+
+_LZMA_OUT_READ - Use read function for output data
+
+_LZMA_LOC_OPT  - Enable local speed optimizations inside code.
+                 _LZMA_LOC_OPT is only for LzmaDecodeSize.c (size-optimized version).
+                 _LZMA_LOC_OPT doesn't affect LzmaDecode.c (speed-optimized version)
+                 and LzmaStateDecode.c
+
+_LZMA_PROB32   - It can increase speed on some 32-bit CPUs, 
+                 but memory usage will be doubled in that case
+
+_LZMA_UINT32_IS_ULONG  - Define it if int is 16-bit on your compiler
+                         and long is 32-bit.
+
+_LZMA_SYSTEM_SIZE_T  - Define it if you want to use system's size_t.
+                       You can use it to enable 64-bit sizes supporting
+
+
+
+C++ LZMA Encoder/Decoder 
+~~~~~~~~~~~~~~~~~~~~~~~~
+C++ LZMA code use COM-like interfaces. So if you want to use it, 
+you can study basics of COM/OLE.
+
+By default, LZMA Encoder contains all Match Finders.
+But for compressing it's enough to have just one of them.
+So for reducing size of compressing code you can define:
+  #define COMPRESS_MF_BT
+  #define COMPRESS_MF_BT4
+and it will use only bt4 match finder.
+
+
+---
+
+http://www.7-zip.org
+http://www.7-zip.org/support.html