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| -rw-r--r-- | other-licenses/7zstub/src/DOC/7zC.txt | 187 |
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diff --git a/other-licenses/7zstub/src/DOC/7zC.txt b/other-licenses/7zstub/src/DOC/7zC.txt new file mode 100644 index 0000000000..49276787f8 --- /dev/null +++ b/other-licenses/7zstub/src/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 <command> <archive_name>
+
+<Command>:
+ 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
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