diff options
Diffstat (limited to 'qemu/roms/u-boot/lib/lzma/lzma.txt')
| -rw-r--r-- | qemu/roms/u-boot/lib/lzma/lzma.txt | 598 |
1 files changed, 598 insertions, 0 deletions
diff --git a/qemu/roms/u-boot/lib/lzma/lzma.txt b/qemu/roms/u-boot/lib/lzma/lzma.txt new file mode 100644 index 000000000..144cd9aee --- /dev/null +++ b/qemu/roms/u-boot/lib/lzma/lzma.txt @@ -0,0 +1,598 @@ +LZMA SDK 9.20 +------------- + +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 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) + + +LZMA SDK Contents +----------------- + +LZMA SDK includes: + + - ANSI-C/C++/C#/Java source code for LZMA compressing and decompressing + - Compiled file->file LZMA compressing/decompressing program for Windows system + + +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 + + +Files +--------------------- +lzma.txt - LZMA SDK description (this file) +7zFormat.txt - 7z Format description +7zC.txt - 7z ANSI-C Decoder description +methods.txt - Compression method IDs for .7z +lzma.exe - Compiled file->file LZMA encoder/decoder for Windows +7zr.exe - 7-Zip with 7z/lzma/xz support. +history.txt - history of the LZMA SDK + + +Source code structure +--------------------- + +C/ - C files + 7zCrc*.* - CRC code + Alloc.* - Memory allocation functions + Bra*.* - Filters for x86, IA-64, ARM, ARM-Thumb, PowerPC and SPARC code + LzFind.* - Match finder for LZ (LZMA) encoders + LzFindMt.* - Match finder for LZ (LZMA) encoders for multithreading encoding + LzHash.h - Additional file for LZ match finder + LzmaDec.* - LZMA decoding + LzmaEnc.* - LZMA encoding + LzmaLib.* - LZMA Library for DLL calling + Types.h - Basic types for another .c files + Threads.* - The code for multithreading. + + LzmaLib - LZMA Library (.DLL for Windows) + + LzmaUtil - LZMA Utility (file->file LZMA encoder/decoder). + + Archive - files related to archiving + 7z - 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 + + 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 + LzmaCon - lzma.exe: LZMA compression/decompression + 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. +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 2 MB/s on 2 GHz CPU + - Estimated decompressing speed: + - 20-30 MB/s on 2 GHz Core 2 or AMD Athlon 64 + - 1-2 MB/s on 200 MHz ARM, MIPS, PowerPC or other simple RISC + - 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) Misspredicted 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. + + +LZMA compressed file format +--------------------------- +Offset Size Description + 0 1 Special LZMA properties (lc,lp, pb in encoded form) + 1 4 Dictionary size (little endian) + 5 8 Uncompressed size (little endian). -1 means unknown size + 13 Compressed data + + +ANSI-C LZMA Decoder +~~~~~~~~~~~~~~~~~~~ + +Please note that interfaces for ANSI-C code were changed in LZMA SDK 4.58. +If you want to use old interfaces you can download previous version of LZMA SDK +from sourceforge.net site. + +To use ANSI-C LZMA Decoder you need the following files: +1) LzmaDec.h + LzmaDec.c + Types.h +LzmaUtil/LzmaUtil.c is example application that uses these files. + + +Memory requirements for LZMA decoding +------------------------------------- + +Stack usage of LZMA decoding function for local variables is not +larger than 200-400 bytes. + +LZMA Decoder uses dictionary buffer and internal state structure. +Internal state structure consumes + state_size = (4 + (1.5 << (lc + lp))) KB +by default (lc=3, lp=0), state_size = 16 KB. + + +How To decompress data +---------------------- + +LZMA Decoder (ANSI-C version) now supports 2 interfaces: +1) Single-call Decompressing +2) Multi-call State Decompressing (zlib-like interface) + +You must use external allocator: +Example: +void *SzAlloc(void *p, size_t size) { p = p; return malloc(size); } +void SzFree(void *p, void *address) { p = p; free(address); } +ISzAlloc alloc = { SzAlloc, SzFree }; + +You can use p = p; operator to disable compiler warnings. + + +Single-call Decompressing +------------------------- +When to use: RAM->RAM decompressing +Compile files: LzmaDec.h + LzmaDec.c + Types.h +Compile defines: no defines +Memory Requirements: + - Input buffer: compressed size + - Output buffer: uncompressed size + - LZMA Internal Structures: state_size (16 KB for default settings) + +Interface: + int LzmaDecode(Byte *dest, SizeT *destLen, const Byte *src, SizeT *srcLen, + const Byte *propData, unsigned propSize, ELzmaFinishMode finishMode, + ELzmaStatus *status, ISzAlloc *alloc); + In: + dest - output data + destLen - output data size + src - input data + srcLen - input data size + propData - LZMA properties (5 bytes) + propSize - size of propData buffer (5 bytes) + finishMode - It has meaning only if the decoding reaches output limit (*destLen). + LZMA_FINISH_ANY - Decode just destLen bytes. + LZMA_FINISH_END - Stream must be finished after (*destLen). + You can use LZMA_FINISH_END, when you know that + current output buffer covers last bytes of stream. + alloc - Memory allocator. + + Out: + destLen - processed output size + srcLen - processed input size + + Output: + SZ_OK + status: + LZMA_STATUS_FINISHED_WITH_MARK + LZMA_STATUS_NOT_FINISHED + LZMA_STATUS_MAYBE_FINISHED_WITHOUT_MARK + SZ_ERROR_DATA - Data error + SZ_ERROR_MEM - Memory allocation error + SZ_ERROR_UNSUPPORTED - Unsupported properties + SZ_ERROR_INPUT_EOF - It needs more bytes in input buffer (src). + + If LZMA decoder sees end_marker before reaching output limit, it returns OK result, + and output value of destLen will be less than output buffer size limit. + + You can use multiple checks to test data integrity after full decompression: + 1) Check Result and "status" variable. + 2) Check that output(destLen) = uncompressedSize, if you know real uncompressedSize. + 3) Check that output(srcLen) = compressedSize, if you know real compressedSize. + You must use correct finish mode in that case. */ + + +Multi-call State Decompressing (zlib-like interface) +---------------------------------------------------- + +When to use: file->file decompressing +Compile files: LzmaDec.h + LzmaDec.c + Types.h + +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: state_size (16 KB for default settings) + - LZMA dictionary (dictionary size is encoded in LZMA properties header) + +1) read LZMA properties (5 bytes) and uncompressed size (8 bytes, little-endian) to header: + unsigned char header[LZMA_PROPS_SIZE + 8]; + ReadFile(inFile, header, sizeof(header) + +2) Allocate CLzmaDec structures (state + dictionary) using LZMA properties + + CLzmaDec state; + LzmaDec_Constr(&state); + res = LzmaDec_Allocate(&state, header, LZMA_PROPS_SIZE, &g_Alloc); + if (res != SZ_OK) + return res; + +3) Init LzmaDec structure before any new LZMA stream. And call LzmaDec_DecodeToBuf in loop + + LzmaDec_Init(&state); + for (;;) + { + ... + int res = LzmaDec_DecodeToBuf(CLzmaDec *p, Byte *dest, SizeT *destLen, + const Byte *src, SizeT *srcLen, ELzmaFinishMode finishMode); + ... + } + + +4) Free all allocated structures + LzmaDec_Free(&state, &g_Alloc); + +For full code example, look at C/LzmaUtil/LzmaUtil.c code. + + +How To compress data +-------------------- + +Compile files: LzmaEnc.h + LzmaEnc.c + Types.h + +LzFind.c + LzFind.h + LzFindMt.c + LzFindMt.h + LzHash.h + +Memory Requirements: + - (dictSize * 11.5 + 6 MB) + state_size + +Lzma Encoder can use two memory allocators: +1) alloc - for small arrays. +2) allocBig - for big arrays. + +For example, you can use Large RAM Pages (2 MB) in allocBig allocator for +better compression speed. Note that Windows has bad implementation for +Large RAM Pages. +It's OK to use same allocator for alloc and allocBig. + + +Single-call Compression with callbacks +-------------------------------------- + +Check C/LzmaUtil/LzmaUtil.c as example, + +When to use: file->file decompressing + +1) you must implement callback structures for interfaces: +ISeqInStream +ISeqOutStream +ICompressProgress +ISzAlloc + +static void *SzAlloc(void *p, size_t size) { p = p; return MyAlloc(size); } +static void SzFree(void *p, void *address) { p = p; MyFree(address); } +static ISzAlloc g_Alloc = { SzAlloc, SzFree }; + + CFileSeqInStream inStream; + CFileSeqOutStream outStream; + + inStream.funcTable.Read = MyRead; + inStream.file = inFile; + outStream.funcTable.Write = MyWrite; + outStream.file = outFile; + + +2) Create CLzmaEncHandle object; + + CLzmaEncHandle enc; + + enc = LzmaEnc_Create(&g_Alloc); + if (enc == 0) + return SZ_ERROR_MEM; + + +3) initialize CLzmaEncProps properties; + + LzmaEncProps_Init(&props); + + Then you can change some properties in that structure. + +4) Send LZMA properties to LZMA Encoder + + res = LzmaEnc_SetProps(enc, &props); + +5) Write encoded properties to header + + Byte header[LZMA_PROPS_SIZE + 8]; + size_t headerSize = LZMA_PROPS_SIZE; + UInt64 fileSize; + int i; + + res = LzmaEnc_WriteProperties(enc, header, &headerSize); + fileSize = MyGetFileLength(inFile); + for (i = 0; i < 8; i++) + header[headerSize++] = (Byte)(fileSize >> (8 * i)); + MyWriteFileAndCheck(outFile, header, headerSize) + +6) Call encoding function: + res = LzmaEnc_Encode(enc, &outStream.funcTable, &inStream.funcTable, + NULL, &g_Alloc, &g_Alloc); + +7) Destroy LZMA Encoder Object + LzmaEnc_Destroy(enc, &g_Alloc, &g_Alloc); + + +If callback function return some error code, LzmaEnc_Encode also returns that code +or it can return the code like SZ_ERROR_READ, SZ_ERROR_WRITE or SZ_ERROR_PROGRESS. + + +Single-call RAM->RAM Compression +-------------------------------- + +Single-call RAM->RAM Compression is similar to Compression with callbacks, +but you provide pointers to buffers instead of pointers to stream callbacks: + +HRes LzmaEncode(Byte *dest, SizeT *destLen, const Byte *src, SizeT srcLen, + CLzmaEncProps *props, Byte *propsEncoded, SizeT *propsSize, int writeEndMark, + ICompressProgress *progress, ISzAlloc *alloc, ISzAlloc *allocBig); + +Return code: + SZ_OK - OK + SZ_ERROR_MEM - Memory allocation error + SZ_ERROR_PARAM - Incorrect paramater + SZ_ERROR_OUTPUT_EOF - output buffer overflow + SZ_ERROR_THREAD - errors in multithreading functions (only for Mt version) + + + +Defines +------- + +_LZMA_SIZE_OPT - Enable some optimizations in LZMA Decoder to get smaller executable code. + +_LZMA_PROB32 - It can increase the speed on some 32-bit CPUs, but memory usage for + some structures 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_NO_SYSTEM_SIZE_T - Define it if you don't want to use size_t type. + + +_7ZIP_PPMD_SUPPPORT - Define it if you don't want to support PPMD method in AMSI-C .7z decoder. + + +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. +C++ LZMA code is just wrapper over ANSI-C code. + + +C++ Notes +~~~~~~~~~~~~~~~~~~~~~~~~ +If you use some C++ code folders in 7-Zip (for example, C++ code for .7z handling), +you must check that you correctly work with "new" operator. +7-Zip can be compiled with MSVC 6.0 that doesn't throw "exception" from "new" operator. +So 7-Zip uses "CPP\Common\NewHandler.cpp" that redefines "new" operator: +operator new(size_t size) +{ + void *p = ::malloc(size); + if (p == 0) + throw CNewException(); + return p; +} +If you use MSCV that throws exception for "new" operator, you can compile without +"NewHandler.cpp". So standard exception will be used. Actually some code of +7-Zip catches any exception in internal code and converts it to HRESULT code. +So you don't need to catch CNewException, if you call COM interfaces of 7-Zip. + +--- + +http://www.7-zip.org +http://www.7-zip.org/sdk.html +http://www.7-zip.org/support.html |