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Diffstat (limited to 'release/src/linux/linux/scripts/squashfs/lzma/lzma.txt')
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diff --git a/release/src/linux/linux/scripts/squashfs/lzma/lzma.txt b/release/src/linux/linux/scripts/squashfs/lzma/lzma.txt new file mode 100644 index 00000000..8b5825fb --- /dev/null +++ b/release/src/linux/linux/scripts/squashfs/lzma/lzma.txt @@ -0,0 +1,637 @@ +LZMA SDK 4.32
+-------------
+
+LZMA SDK 4.32 Copyright (C) 1999-2005 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 examples (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 / 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 / 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
+ BinTree - Binary Tree Match Finder for LZ algorithm
+ HashChain - Hash Chain Match Finder for LZ algorithm
+ Patricia - Patricia Match Finder for LZ algorithm
+ RangeCoder - Range Coder (special code of compression/decompression)
+ LZMA - LZMA compression/decompression on C++
+ LZMA_Alone - file->file LZMA compression/decompression
+ LZMA_C - 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
+ 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
+
+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_C
+7-Zip doesn't use that ANSI-C LZMA code and that code was developed
+specially for this SDK. And files from LZMA_C 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 Decompression features
+---------------------------
+ - Variable dictionary size (up to 256 MB)
+ - Estimated compressing speed: about 500 KB/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 XP 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, 2 = max
+ default: 2 (max)
+
+ d{N}: Sets Dictionary size - [0, 28], default: 23 (8MB)
+ The maximum value for dictionary size is 256 MB = 2^28 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.
+ Compression ratio for all bt* and pat* almost the same.
+ Algorithms from hc* group doesn't provide good compression
+ ratio, but they often works pretty fast in combination with
+ fast mode (-a0). Methods from bt* group require less memory
+ than methods from pat* group. Usually bt4 works faster than
+ any pat*, but for some types of files pat* can work faster.
+
+ Memory requirements depend from dictionary size
+ (parameter "d" in table below).
+
+ MF_ID Memory Description
+
+ bt2 d*9.5 + 1MB Binary Tree with 2 bytes hashing.
+ bt3 d*9.5 + 65MB Binary Tree with 2-3(full) bytes hashing.
+ bt4 d*9.5 + 6MB Binary Tree with 2-3-4 bytes hashing.
+ bt4b d*9.5 + 34MB Binary Tree with 2-3-4(big) bytes hashing.
+ pat2r d*26 + 1MB Patricia Tree with 2-bits nodes, removing.
+ pat2 d*38 + 1MB Patricia Tree with 2-bits nodes.
+ pat2h d*38 + 77MB Patricia Tree with 2-bits nodes, 2-3 bytes hashing.
+ pat3h d*62 + 85MB Patricia Tree with 3-bits nodes, 2-3 bytes hashing.
+ pat4h d*110 +101MB Patricia Tree with 4-bits nodes, 2-3 bytes hashing.
+ hc3 d*5.5 + 1MB Hash Chain with 2-3 bytes hashing.
+ hc4 d*5.5 + 6MB Hash Chain with 2-3-4 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
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