1 /* Lzma86.h -- LZMA + x86 (BCJ) Filter 2 2013-01-18 : Igor Pavlov : Public domain */ 3 4 #ifndef __LZMA86_H 5 #define __LZMA86_H 6 7 #include "7zTypes.h" 8 9 EXTERN_C_BEGIN 10 11 #define LZMA86_SIZE_OFFSET (1 + 5) 12 #define LZMA86_HEADER_SIZE (LZMA86_SIZE_OFFSET + 8) 13 14 /* 15 It's an example for LZMA + x86 Filter use. 16 You can use .lzma86 extension, if you write that stream to file. 17 .lzma86 header adds one additional byte to standard .lzma header. 18 .lzma86 header (14 bytes): 19 Offset Size Description 20 0 1 = 0 - no filter, pure LZMA 21 = 1 - x86 filter + LZMA 22 1 1 lc, lp and pb in encoded form 23 2 4 dictSize (little endian) 24 6 8 uncompressed size (little endian) 25 26 27 Lzma86_Encode 28 ------------- 29 level - compression level: 0 <= level <= 9, the default value for "level" is 5. 30 31 dictSize - The dictionary size in bytes. The maximum value is 32 128 MB = (1 << 27) bytes for 32-bit version 33 1 GB = (1 << 30) bytes for 64-bit version 34 The default value is 16 MB = (1 << 24) bytes, for level = 5. 35 It's recommended to use the dictionary that is larger than 4 KB and 36 that can be calculated as (1 << N) or (3 << N) sizes. 37 For better compression ratio dictSize must be >= inSize. 38 39 filterMode: 40 SZ_FILTER_NO - no Filter 41 SZ_FILTER_YES - x86 Filter 42 SZ_FILTER_AUTO - it tries both alternatives to select best. 43 Encoder will use 2 or 3 passes: 44 2 passes when FILTER_NO provides better compression. 45 3 passes when FILTER_YES provides better compression. 46 47 Lzma86Encode allocates Data with MyAlloc functions. 48 RAM Requirements for compressing: 49 RamSize = dictionarySize * 11.5 + 6MB + FilterBlockSize 50 filterMode FilterBlockSize 51 SZ_FILTER_NO 0 52 SZ_FILTER_YES inSize 53 SZ_FILTER_AUTO inSize 54 55 56 Return code: 57 SZ_OK - OK 58 SZ_ERROR_MEM - Memory allocation error 59 SZ_ERROR_PARAM - Incorrect paramater 60 SZ_ERROR_OUTPUT_EOF - output buffer overflow 61 SZ_ERROR_THREAD - errors in multithreading functions (only for Mt version) 62 */ 63 64 enum ESzFilterMode 65 { 66 SZ_FILTER_NO, 67 SZ_FILTER_YES, 68 SZ_FILTER_AUTO 69 }; 70 71 SRes Lzma86_Encode(Byte *dest, size_t *destLen, const Byte *src, size_t srcLen, 72 int level, UInt32 dictSize, int filterMode); 73 74 75 /* 76 Lzma86_GetUnpackSize: 77 In: 78 src - input data 79 srcLen - input data size 80 Out: 81 unpackSize - size of uncompressed stream 82 Return code: 83 SZ_OK - OK 84 SZ_ERROR_INPUT_EOF - Error in headers 85 */ 86 87 SRes Lzma86_GetUnpackSize(const Byte *src, SizeT srcLen, UInt64 *unpackSize); 88 89 /* 90 Lzma86_Decode: 91 In: 92 dest - output data 93 destLen - output data size 94 src - input data 95 srcLen - input data size 96 Out: 97 destLen - processed output size 98 srcLen - processed input size 99 Return code: 100 SZ_OK - OK 101 SZ_ERROR_DATA - Data error 102 SZ_ERROR_MEM - Memory allocation error 103 SZ_ERROR_UNSUPPORTED - unsupported file 104 SZ_ERROR_INPUT_EOF - it needs more bytes in input buffer 105 */ 106 107 SRes Lzma86_Decode(Byte *dest, SizeT *destLen, const Byte *src, SizeT *srcLen); 108 109 EXTERN_C_END 110 111 #endif 112
