From ce188d4d7f3b9ad04867c49b424e8497c2ade92b Mon Sep 17 00:00:00 2001 From: aliaspider Date: Tue, 14 May 2019 08:58:52 +0100 Subject: add CHD support. --- deps/lzma-16.04/DOC/7zC.txt | 187 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 187 insertions(+) create mode 100644 deps/lzma-16.04/DOC/7zC.txt (limited to 'deps/lzma-16.04/DOC/7zC.txt') diff --git a/deps/lzma-16.04/DOC/7zC.txt b/deps/lzma-16.04/DOC/7zC.txt new file mode 100644 index 0000000..4927678 --- /dev/null +++ b/deps/lzma-16.04/DOC/7zC.txt @@ -0,0 +1,187 @@ +7z ANSI-C Decoder 9.35 +---------------------- + +7z ANSI-C provides 7z/LZMA decoding. +7z ANSI-C version is simplified version ported from C++ code. + +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. + + +LICENSE +------- + +7z ANSI-C Decoder is part of the LZMA SDK. +LZMA SDK is written and placed in the public domain by Igor Pavlov. + +Files +--------------------- + +7zDecode.* - Low level 7z decoding +7zExtract.* - High level 7z decoding +7zHeader.* - .7z format constants +7zIn.* - .7z archive opening +7zItem.* - .7z structures +7zMain.c - Test application + + +How To Use +---------- + +You can create .7z archive with 7z.exe, 7za.exe or 7zr.exe: + + 7z.exe a archive.7z *.htm -r -mx -m0fb=255 + +If you have big number of files in archive, and you need fast extracting, +you can use partly-solid archives: + + 7za.exe a archive.7z *.htm -ms=512K -r -mx -m0fb=255 -m0d=512K + +In that example 7-Zip will use 512KB solid blocks. So it needs to decompress only +512KB for extracting one file from such archive. + + +Limitations of current version of 7z ANSI-C Decoder +--------------------------------------------------- + + - It reads only "FileName", "Size", "LastWriteTime" and "CRC" information for each file in archive. + - It supports only LZMA and Copy (no compression) methods with BCJ or BCJ2 filters. + - It converts original UTF-16 Unicode file names to UTF-8 Unicode file names. + +These limitations will be fixed in future versions. + + +Using 7z ANSI-C Decoder Test application: +----------------------------------------- + +Usage: 7zDec + +: + e: Extract files from archive + l: List contents of archive + t: Test integrity of archive + +Example: + + 7zDec l archive.7z + +lists contents of archive.7z + + 7zDec e archive.7z + +extracts files from archive.7z to current folder. + + +How to use .7z Decoder +---------------------- + +Memory allocation +~~~~~~~~~~~~~~~~~ + +7z Decoder uses two memory pools: +1) Temporary pool +2) Main pool +Such scheme can allow you to avoid fragmentation of allocated blocks. + + +Steps for using 7z decoder +-------------------------- + +Use code at 7zMain.c as example. + +1) Declare variables: + inStream /* implements ILookInStream interface */ + CSzArEx db; /* 7z archive database structure */ + ISzAlloc allocImp; /* memory functions for main pool */ + ISzAlloc allocTempImp; /* memory functions for temporary pool */ + +2) call CrcGenerateTable(); function to initialize CRC structures. + +3) call SzArEx_Init(&db); function to initialize db structures. + +4) call SzArEx_Open(&db, inStream, &allocMain, &allocTemp) to open archive + +This function opens archive "inStream" and reads headers to "db". +All items in "db" will be allocated with "allocMain" functions. +SzArEx_Open function allocates and frees temporary structures by "allocTemp" functions. + +5) List items or Extract items + + Listing code: + ~~~~~~~~~~~~~ + + Use SzArEx_GetFileNameUtf16 function. Look example code in C\Util\7z\7zMain.c file. + + + Extracting code: + ~~~~~~~~~~~~~~~~ + + SZ_RESULT SzAr_Extract( + CArchiveDatabaseEx *db, + ILookInStream *inStream, + UInt32 fileIndex, /* index of file */ + UInt32 *blockIndex, /* index of solid block */ + Byte **outBuffer, /* pointer to pointer to output buffer (allocated with allocMain) */ + size_t *outBufferSize, /* buffer size for output buffer */ + size_t *offset, /* offset of stream for required file in *outBuffer */ + size_t *outSizeProcessed, /* size of file in *outBuffer */ + ISzAlloc *allocMain, + ISzAlloc *allocTemp); + + If you need to decompress more than one file, you can send these values from previous call: + blockIndex, + outBuffer, + outBufferSize, + You can consider "outBuffer" as cache of solid block. If your archive is solid, + it will increase decompression speed. + + After decompressing you must free "outBuffer": + allocImp.Free(outBuffer); + +6) call SzArEx_Free(&db, allocImp.Free) to free allocated items in "db". + + + + +Memory requirements for .7z decoding +------------------------------------ + +Memory usage for Archive opening: + - Temporary pool: + - Memory for uncompressed .7z headers + - some other temporary blocks + - Main pool: + - Memory for database: + Estimated size of one file structures in solid archive: + - Size (4 or 8 Bytes) + - CRC32 (4 bytes) + - LastWriteTime (8 bytes) + - Some file information (4 bytes) + - File Name (variable length) + pointer + allocation structures + +Memory usage for archive Decompressing: + - Temporary pool: + - Memory for LZMA decompressing structures + - Main pool: + - Memory for decompressed solid block + - Memory for temprorary buffers, if BCJ2 fileter is used. Usually these + temprorary buffers can be about 15% of solid block size. + + +7z Decoder doesn't allocate memory for compressed blocks. +Instead of this, you must allocate buffer with desired +size before calling 7z Decoder. Use 7zMain.c as example. + + +Defines +------- + +_SZ_ALLOC_DEBUG - define it if you want to debug alloc/free operations to stderr. + + +--- + +http://www.7-zip.org +http://www.7-zip.org/sdk.html +http://www.7-zip.org/support.html -- cgit v1.2.3