LzmaLib.h (4438B)
1 /* LzmaLib.h -- LZMA library interface 2 2013-01-18 : Igor Pavlov : Public domain */ 3 4 #ifndef __LZMA_LIB_H 5 #define __LZMA_LIB_H 6 7 #include "7zTypes.h" 8 9 EXTERN_C_BEGIN 10 11 #define MY_STDAPI int MY_STD_CALL 12 13 #define LZMA_PROPS_SIZE 5 14 15 /* 16 RAM requirements for LZMA: 17 for compression: (dictSize * 11.5 + 6 MB) + state_size 18 for decompression: dictSize + state_size 19 state_size = (4 + (1.5 << (lc + lp))) KB 20 by default (lc=3, lp=0), state_size = 16 KB. 21 22 LZMA properties (5 bytes) format 23 Offset Size Description 24 0 1 lc, lp and pb in encoded form. 25 1 4 dictSize (little endian). 26 */ 27 28 /* 29 LzmaCompress 30 ------------ 31 32 outPropsSize - 33 In: the pointer to the size of outProps buffer; *outPropsSize = LZMA_PROPS_SIZE = 5. 34 Out: the pointer to the size of written properties in outProps buffer; *outPropsSize = LZMA_PROPS_SIZE = 5. 35 36 LZMA Encoder will use defult values for any parameter, if it is 37 -1 for any from: level, loc, lp, pb, fb, numThreads 38 0 for dictSize 39 40 level - compression level: 0 <= level <= 9; 41 42 level dictSize algo fb 43 0: 16 KB 0 32 44 1: 64 KB 0 32 45 2: 256 KB 0 32 46 3: 1 MB 0 32 47 4: 4 MB 0 32 48 5: 16 MB 1 32 49 6: 32 MB 1 32 50 7+: 64 MB 1 64 51 52 The default value for "level" is 5. 53 54 algo = 0 means fast method 55 algo = 1 means normal method 56 57 dictSize - The dictionary size in bytes. The maximum value is 58 128 MB = (1 << 27) bytes for 32-bit version 59 1 GB = (1 << 30) bytes for 64-bit version 60 The default value is 16 MB = (1 << 24) bytes. 61 It's recommended to use the dictionary that is larger than 4 KB and 62 that can be calculated as (1 << N) or (3 << N) sizes. 63 64 lc - The number of literal context bits (high bits of previous literal). 65 It can be in the range from 0 to 8. The default value is 3. 66 Sometimes lc=4 gives the gain for big files. 67 68 lp - The number of literal pos bits (low bits of current position for literals). 69 It can be in the range from 0 to 4. The default value is 0. 70 The lp switch is intended for periodical data when the period is equal to 2^lp. 71 For example, for 32-bit (4 bytes) periodical data you can use lp=2. Often it's 72 better to set lc=0, if you change lp switch. 73 74 pb - The number of pos bits (low bits of current position). 75 It can be in the range from 0 to 4. The default value is 2. 76 The pb switch is intended for periodical data when the period is equal 2^pb. 77 78 fb - Word size (the number of fast bytes). 79 It can be in the range from 5 to 273. The default value is 32. 80 Usually, a big number gives a little bit better compression ratio and 81 slower compression process. 82 83 numThreads - The number of thereads. 1 or 2. The default value is 2. 84 Fast mode (algo = 0) can use only 1 thread. 85 86 Out: 87 destLen - processed output size 88 Returns: 89 SZ_OK - OK 90 SZ_ERROR_MEM - Memory allocation error 91 SZ_ERROR_PARAM - Incorrect paramater 92 SZ_ERROR_OUTPUT_EOF - output buffer overflow 93 SZ_ERROR_THREAD - errors in multithreading functions (only for Mt version) 94 */ 95 96 MY_STDAPI LzmaCompress(unsigned char *dest, size_t *destLen, const unsigned char *src, size_t srcLen, 97 unsigned char *outProps, size_t *outPropsSize, /* *outPropsSize must be = 5 */ 98 int level, /* 0 <= level <= 9, default = 5 */ 99 unsigned dictSize, /* default = (1 << 24) */ 100 int lc, /* 0 <= lc <= 8, default = 3 */ 101 int lp, /* 0 <= lp <= 4, default = 0 */ 102 int pb, /* 0 <= pb <= 4, default = 2 */ 103 int fb, /* 5 <= fb <= 273, default = 32 */ 104 int numThreads /* 1 or 2, default = 2 */ 105 ); 106 107 /* 108 LzmaUncompress 109 -------------- 110 In: 111 dest - output data 112 destLen - output data size 113 src - input data 114 srcLen - input data size 115 Out: 116 destLen - processed output size 117 srcLen - processed input size 118 Returns: 119 SZ_OK - OK 120 SZ_ERROR_DATA - Data error 121 SZ_ERROR_MEM - Memory allocation arror 122 SZ_ERROR_UNSUPPORTED - Unsupported properties 123 SZ_ERROR_INPUT_EOF - it needs more bytes in input buffer (src) 124 */ 125 126 MY_STDAPI LzmaUncompress(unsigned char *dest, size_t *destLen, const unsigned char *src, SizeT *srcLen, 127 const unsigned char *props, size_t propsSize); 128 129 EXTERN_C_END 130 131 #endif