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+++ b/misc/libphysfs/lzma/7zC.txt Mon Apr 10 12:06:43 2017 -0400
@@ -0,0 +1,237 @@
+7z ANSI-C Decoder 4.48
+----------------------
+
+7z ANSI-C Decoder 4.48 Copyright (C) 1999-2006 Igor Pavlov
+
+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
+-------
+
+Read lzma.txt for information about license.
+
+
+Files
+---------------------
+
+7zAlloc.* - Allocate and Free
+7zBuffer.* - Buffer structure
+7zCrc.* - CRC32 code
+7zDecode.* - Low level memory->memory decoding
+7zExtract.* - High level stream->memory decoding
+7zHeader.* - .7z format constants
+7zIn.* - .7z archive opening
+7zItem.* - .7z structures
+7zMain.c - Test application
+7zMethodID.* - MethodID structure
+7zTypes.h - Base types and constants
+
+
+How To Use
+----------
+
+You must download 7-Zip program from www.7-zip.org.
+
+You can create .7z archive with 7z.exe or 7za.exe:
+
+ 7za.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
+----------------------
+
+.7z Decoder can be compiled in one of two modes:
+
+1) Default mode. In that mode 7z Decoder will read full compressed
+ block to RAM before decompressing.
+
+2) Mode with defined _LZMA_IN_CB. In that mode 7z Decoder can read
+ compressed block by parts. And you can specify desired buffer size.
+ So memory requirements can be reduced. But decompressing speed will
+ be 5-10% lower and code size is slightly larger.
+
+
+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 ISzInStream interface */
+ CArchiveDatabaseEx db; /* 7z archive database structure */
+ ISzAlloc allocImp; /* memory functions for main pool */
+ ISzAlloc allocTempImp; /* memory functions for temporary pool */
+
+2) call InitCrcTable(); function to initialize CRC structures.
+
+3) call SzArDbExInit(&db); function to initialize db structures.
+
+4) call SzArchiveOpen(inStream, &db, &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.
+SzArchiveOpen function allocates and frees temporary structures by "allocTemp" functions.
+
+5) List items or Extract items
+
+ Listing code:
+ ~~~~~~~~~~~~~
+ {
+ UInt32 i;
+ for (i = 0; i < db.Database.NumFiles; i++)
+ {
+ CFileItem *f = db.Database.Files + i;
+ printf("%10d %s\n", (int)f->Size, f->Name);
+ }
+ }
+
+ Extracting code:
+ ~~~~~~~~~~~~~~~~
+
+ SZ_RESULT SzExtract(
+ ISzInStream *inStream,
+ CArchiveDatabaseEx *db,
+ 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 SzArDbExFree(&db, allocImp.Free) to free allocated items in "db".
+
+
+
+
+Memory requirements for .7z decoding
+------------------------------------
+
+Memory usage for Archive opening:
+ - Temporary pool:
+ - Memory for compressed .7z headers (if _LZMA_IN_CB is not defined)
+ - 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 compressed solid block (if _LZMA_IN_CB is not defined)
+ - 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.
+
+
+If _LZMA_IN_CB is defined, 7z Decoder will not allocate memory for
+compressed blocks. Instead of this, you must allocate buffer with desired
+size before calling 7z Decoder. Use 7zMain.c as example.
+
+
+
+EXIT codes
+-----------
+
+7z Decoder functions can return one of the following codes:
+
+#define SZ_OK (0)
+#define SZE_DATA_ERROR (1)
+#define SZE_OUTOFMEMORY (2)
+#define SZE_CRC_ERROR (3)
+
+#define SZE_NOTIMPL (4)
+#define SZE_FAIL (5)
+
+#define SZE_ARCHIVE_ERROR (6)
+
+
+
+LZMA Defines
+------------
+
+_LZMA_IN_CB - Use special callback mode for input stream to reduce memory requirements
+
+_SZ_FILE_SIZE_32 - define it if you need only support for files smaller than 4 GB
+_SZ_NO_INT_64 - define it if your compiler doesn't support long long int or __int64.
+
+_LZMA_PROB32 - it can increase LZMA decompressing speed on some 32-bit CPUs.
+
+_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/support.html