/* LzmaLib.h -- LZMA library interface 2021-04-03 : Igor Pavlov : Public domain */ #ifndef __LZMA_LIB_H #define __LZMA_LIB_H #include "7zTypes.h" EXTERN_C_BEGIN #define MY_STDAPI … #define LZMA_PROPS_SIZE … /* RAM requirements for LZMA: for compression: (dictSize * 11.5 + 6 MB) + state_size for decompression: dictSize + state_size state_size = (4 + (1.5 << (lc + lp))) KB by default (lc=3, lp=0), state_size = 16 KB. LZMA properties (5 bytes) format Offset Size Description 0 1 lc, lp and pb in encoded form. 1 4 dictSize (little endian). */ /* LzmaCompress ------------ outPropsSize - In: the pointer to the size of outProps buffer; *outPropsSize = LZMA_PROPS_SIZE = 5. Out: the pointer to the size of written properties in outProps buffer; *outPropsSize = LZMA_PROPS_SIZE = 5. LZMA Encoder will use defult values for any parameter, if it is -1 for any from: level, loc, lp, pb, fb, numThreads 0 for dictSize level - compression level: 0 <= level <= 9; level dictSize algo fb 0: 64 KB 0 32 1: 256 KB 0 32 2: 1 MB 0 32 3: 4 MB 0 32 4: 16 MB 0 32 5: 16 MB 1 32 6: 32 MB 1 32 7: 32 MB 1 64 8: 64 MB 1 64 9: 64 MB 1 64 The default value for "level" is 5. algo = 0 means fast method algo = 1 means normal method dictSize - The dictionary size in bytes. The maximum value is 128 MB = (1 << 27) bytes for 32-bit version 1 GB = (1 << 30) bytes for 64-bit version The default value is 16 MB = (1 << 24) bytes. It's recommended to use the dictionary that is larger than 4 KB and that can be calculated as (1 << N) or (3 << N) sizes. lc - The number of literal context bits (high bits of previous literal). It can be in the range from 0 to 8. The default value is 3. Sometimes lc=4 gives the gain for big files. lp - The number of literal pos bits (low bits of current position for literals). It can be in the range from 0 to 4. The default value is 0. The lp switch is intended for periodical data when the period is equal to 2^lp. For example, for 32-bit (4 bytes) periodical data you can use lp=2. Often it's better to set lc=0, if you change lp switch. pb - The number of pos bits (low bits of current position). It can be in the range from 0 to 4. The default value is 2. The pb switch is intended for periodical data when the period is equal 2^pb. fb - Word size (the number of fast bytes). It can be in the range from 5 to 273. The default value is 32. Usually, a big number gives a little bit better compression ratio and slower compression process. numThreads - The number of thereads. 1 or 2. The default value is 2. Fast mode (algo = 0) can use only 1 thread. In: dest - output data buffer destLen - output data buffer size src - input data srcLen - input data size Out: destLen - processed output size Returns: SZ_OK - OK SZ_ERROR_MEM - Memory allocation error SZ_ERROR_PARAM - Incorrect paramater SZ_ERROR_OUTPUT_EOF - output buffer overflow SZ_ERROR_THREAD - errors in multithreading functions (only for Mt version) */ MY_STDAPI LzmaCompress(unsigned char *dest, size_t *destLen, const unsigned char *src, size_t srcLen, unsigned char *outProps, size_t *outPropsSize, /* *outPropsSize must be = 5 */ int level, /* 0 <= level <= 9, default = 5 */ unsigned dictSize, /* default = (1 << 24) */ int lc, /* 0 <= lc <= 8, default = 3 */ int lp, /* 0 <= lp <= 4, default = 0 */ int pb, /* 0 <= pb <= 4, default = 2 */ int fb, /* 5 <= fb <= 273, default = 32 */ int numThreads /* 1 or 2, default = 2 */ ); /* LzmaUncompress -------------- In: dest - output data buffer destLen - output data buffer size src - input data srcLen - input data size Out: destLen - processed output size srcLen - processed input size Returns: SZ_OK - OK SZ_ERROR_DATA - Data error SZ_ERROR_MEM - Memory allocation arror SZ_ERROR_UNSUPPORTED - Unsupported properties SZ_ERROR_INPUT_EOF - it needs more bytes in input buffer (src) */ MY_STDAPI LzmaUncompress(unsigned char *dest, size_t *destLen, const unsigned char *src, SizeT *srcLen, const unsigned char *props, size_t propsSize); EXTERN_C_END #endif
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