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Diffstat (limited to 'other-licenses/7zstub/src/DOC/lzma.txt')
| -rw-r--r-- | other-licenses/7zstub/src/DOC/lzma.txt | 758 |
1 files changed, 228 insertions, 530 deletions
diff --git a/other-licenses/7zstub/src/DOC/lzma.txt b/other-licenses/7zstub/src/DOC/lzma.txt index fc7fae1bca..1f92142ead 100644 --- a/other-licenses/7zstub/src/DOC/lzma.txt +++ b/other-licenses/7zstub/src/DOC/lzma.txt @@ -1,630 +1,328 @@ -LZMA SDK 4.40
--------------
+LZMA compression
+----------------
+Version: 9.35
-LZMA SDK Copyright (C) 1999-2006 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.
+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)
-
-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 / 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
- 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
-
-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 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.
+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 for compressed data
+ 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
~~~~~~~~~~~~~~~~~~~
-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)
+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
-------------------------------------
-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.
+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 5 interfaces:
+LZMA Decoder (ANSI-C version) now supports 2 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)
+2) Multi-call State Decompressing (zlib-like interface)
-Variant-5 is similar to Variant-4, but Variant-5 doesn't use callback functions.
+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 };
-Decompressing steps
--------------------
+You can use p = p; operator to disable compiler warnings.
-1) read LZMA properties (5 bytes):
- unsigned char properties[LZMA_PROPERTIES_SIZE];
-2) read uncompressed size (8 bytes, little-endian)
+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)
-3) Decode properties:
+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)
+----------------------------------------------------
- CLzmaDecoderState state; /* it's 24-140 bytes structure, if int is 32-bit */
+When to use: file->file decompressing
+Compile files: LzmaDec.h + LzmaDec.c + 7zTypes.h
- if (LzmaDecodeProperties(&state.Properties, properties, LZMA_PROPERTIES_SIZE) != LZMA_RESULT_OK)
- return PrintError(rs, "Incorrect stream properties");
+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)
-4) Allocate memory block for internal Structures:
+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)
- state.Probs = (CProb *)malloc(LzmaGetNumProbs(&state.Properties) * sizeof(CProb));
- if (state.Probs == 0)
- return PrintError(rs, kCantAllocateMessage);
+2) Allocate CLzmaDec structures (state + dictionary) using LZMA properties
- 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.
+ 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
-5) Main Decompressing
+ LzmaDec_Init(&state);
+ for (;;)
+ {
+ ...
+ int res = LzmaDec_DecodeToBuf(CLzmaDec *p, Byte *dest, SizeT *destLen,
+ const Byte *src, SizeT *srcLen, ELzmaFinishMode finishMode);
+ ...
+ }
-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)
+4) Free all allocated structures
+ LzmaDec_Free(&state, &g_Alloc);
-Interface:
- int res = LzmaDecode(&state,
- inStream, compressedSize, &inProcessed,
- outStream, outSize, &outProcessed);
+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
-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)
+ - (dictSize * 11.5 + 6 MB) + state_size
-Interface:
- typedef struct _CBuffer
- {
- ILzmaInCallback InCallback;
- FILE *File;
- unsigned char Buffer[kInBufferSize];
- } CBuffer;
+Lzma Encoder can use two memory allocators:
+1) alloc - for small arrays.
+2) allocBig - for big arrays.
- 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;
- }
+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.
- CBuffer g_InBuffer;
- g_InBuffer.File = inFile;
- g_InBuffer.InCallback.Read = LzmaReadCompressed;
- int res = LzmaDecode(&state,
- &g_InBuffer.InCallback,
- outStream, outSize, &outProcessed);
+Single-call Compression with callbacks
+--------------------------------------
+Look example code:
+ C/Util/Lzma/LzmaUtil.c
-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:
+When to use: file->file compressing
- state.Dictionary = (unsigned char *)malloc(state.Properties.DictionarySize);
+1) you must implement callback structures for interfaces:
+ISeqInStream
+ISeqOutStream
+ICompressProgress
+ISzAlloc
- LzmaDecoderInit(&state);
- do
- {
- LzmaDecode(&state,
- inBuffer, inAvail, &inProcessed,
- g_OutBuffer, outAvail, &outProcessed);
- inAvail -= inProcessed;
- inBuffer += inProcessed;
- }
- while you need more bytes
+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 };
- see LzmaTest.c for more details.
+ CFileSeqInStream inStream;
+ CFileSeqOutStream outStream;
+ inStream.funcTable.Read = MyRead;
+ inStream.file = inFile;
+ outStream.funcTable.Write = MyWrite;
+ outStream.file = outFile;
-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
+2) Create CLzmaEncHandle object;
- see LzmaTest.c for more details:
+ CLzmaEncHandle enc;
+ enc = LzmaEnc_Create(&g_Alloc);
+ if (enc == 0)
+ return SZ_ERROR_MEM;
-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);
+3) initialize CLzmaEncProps properties;
-
- LzmaDecoderInit(&state);
- do
- {
- res = LzmaDecode(&state,
- inBuffer, inAvail, &inProcessed,
- g_OutBuffer, outAvail, &outProcessed,
- finishDecoding);
- inAvail -= inProcessed;
- inBuffer += inProcessed;
- }
- while you need more bytes
+ LzmaEncProps_Init(&props);
+
+ Then you can change some properties in that structure.
- see LzmaStateTest.c for more details:
+4) Send LZMA properties to LZMA Encoder
+ res = LzmaEnc_SetProps(enc, &props);
-6) Free all allocated blocks
+5) Write encoded properties to header
+ Byte header[LZMA_PROPS_SIZE + 8];
+ size_t headerSize = LZMA_PROPS_SIZE;
+ UInt64 fileSize;
+ int i;
-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.
+ 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);
-EXIT codes
------------
+7) Destroy LZMA Encoder Object
+ LzmaEnc_Destroy(enc, &g_Alloc, &g_Alloc);
-LZMA decoder can return one of the following codes:
-#define LZMA_RESULT_OK 0
-#define LZMA_RESULT_DATA_ERROR 1
+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.
-If you use callback function for input data and you return some
-error code, LZMA Decoder also returns that code.
+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:
-LZMA Defines
-------------
+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);
-_LZMA_IN_CB - Use callback for input data
+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)
-_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
+Defines
+-------
+
+_LZMA_SIZE_OPT - Enable some optimizations in LZMA Decoder to get smaller executable code.
-_LZMA_UINT32_IS_ULONG - Define it if int is 16-bit on your compiler
- and long is 32-bit.
+_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_SYSTEM_SIZE_T - Define it if you want to use system's size_t.
- You can use it to enable 64-bit sizes supporting
+_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.
-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.
+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
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