X-Git-Url: https://notaz.gp2x.de/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=deps%2Flibchdr%2Fdeps%2Flzma-22.01%2Flzma.txt;fp=deps%2Flibchdr%2Fdeps%2Flzma-22.01%2Flzma.txt;h=1f92142eaddbd3476ba1809ad725be810ba5a02d;hb=9e052883388b2b607a488e48b3cb6db52a0997dd;hp=0000000000000000000000000000000000000000;hpb=7e49a25d527a1d79569f39a6f2d8d28a0d6cebd5;p=pcsx_rearmed.git diff --git a/deps/libchdr/deps/lzma-22.01/lzma.txt b/deps/libchdr/deps/lzma-22.01/lzma.txt new file mode 100644 index 00000000..1f92142e --- /dev/null +++ b/deps/libchdr/deps/lzma-22.01/lzma.txt @@ -0,0 +1,328 @@ +LZMA compression +---------------- +Version: 9.35 + +This file describes LZMA encoding and decoding functions written in C language. + +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. + +Note: you can read also LZMA Specification (lzma-specification.txt from LZMA SDK) + +Also you can look source code for LZMA encoding and decoding: + C/Util/Lzma/LzmaUtil.c + + +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 + 7zTypes.h + Precomp.h + Compiler.h + +Look example code: + C/Util/Lzma/LzmaUtil.c + + +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 + 7zTypes.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 + 7zTypes.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); + +Look example code: + C/Util/Lzma/LzmaUtil.c + + +How To compress data +-------------------- + +Compile files: + 7zTypes.h + Threads.h + LzmaEnc.h + LzmaEnc.c + LzFind.h + LzFind.c + LzFindMt.h + LzFindMt.c + 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 +-------------------------------------- + +Look example code: + C/Util/Lzma/LzmaUtil.c + +When to use: file->file compressing + +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: + +SRes LzmaEncode(Byte *dest, SizeT *destLen, const Byte *src, SizeT srcLen, + const 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