147 lines
4.5 KiB
C++
147 lines
4.5 KiB
C++
/* LzmaLib.h -- LZMA library interface
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2008-08-05
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Igor Pavlov
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Public domain */
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#ifndef __LZMALIB_H
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#define __LZMALIB_H
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#include "lzma_Types.h"
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namespace crnlib {
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#if 0
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#ifdef __cplusplus
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#define MY_EXTERN_C extern "C"
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#else
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#define MY_EXTERN_C extern
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#endif
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#define MY_STDAPI MY_EXTERN_C int MY_STD_CALL
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#else
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#define MY_STDAPI int MY_STD_CALL
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#endif
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#define LZMA_PROPS_SIZE 5
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/*
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RAM requirements for LZMA:
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for compression: (dictSize * 11.5 + 6 MB) + state_size
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for decompression: dictSize + state_size
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state_size = (4 + (1.5 << (lc + lp))) KB
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by default (lc=3, lp=0), state_size = 16 KB.
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LZMA properties (5 bytes) format
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Offset Size Description
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0 1 lc, lp and pb in encoded form.
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1 4 dictSize (little endian).
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*/
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/*
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LzmaCompress
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------------
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outPropsSize -
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In: the pointer to the size of outProps buffer; *outPropsSize = LZMA_PROPS_SIZE = 5.
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Out: the pointer to the size of written properties in outProps buffer; *outPropsSize = LZMA_PROPS_SIZE = 5.
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LZMA Encoder will use defult values for any parameter, if it is
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-1 for any from: level, loc, lp, pb, fb, numThreads
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0 for dictSize
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level - compression level: 0 <= level <= 9;
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level dictSize algo fb
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0: 16 KB 0 32
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1: 64 KB 0 32
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2: 256 KB 0 32
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3: 1 MB 0 32
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4: 4 MB 0 32
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5: 16 MB 1 32
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6: 32 MB 1 32
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7+: 64 MB 1 64
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The default value for "level" is 5.
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algo = 0 means fast method
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algo = 1 means normal method
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dictSize - The dictionary size in bytes. The maximum value is
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128 MB = (1 << 27) bytes for 32-bit version
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1 GB = (1 << 30) bytes for 64-bit version
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The default value is 16 MB = (1 << 24) bytes.
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It's recommended to use the dictionary that is larger than 4 KB and
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that can be calculated as (1 << N) or (3 << N) sizes.
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lc - The number of literal context bits (high bits of previous literal).
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It can be in the range from 0 to 8. The default value is 3.
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Sometimes lc=4 gives the gain for big files.
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lp - The number of literal pos bits (low bits of current position for literals).
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It can be in the range from 0 to 4. The default value is 0.
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The lp switch is intended for periodical data when the period is equal to 2^lp.
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For example, for 32-bit (4 bytes) periodical data you can use lp=2. Often it's
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better to set lc=0, if you change lp switch.
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pb - The number of pos bits (low bits of current position).
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It can be in the range from 0 to 4. The default value is 2.
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The pb switch is intended for periodical data when the period is equal 2^pb.
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fb - Word size (the number of fast bytes).
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It can be in the range from 5 to 273. The default value is 32.
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Usually, a big number gives a little bit better compression ratio and
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slower compression process.
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numThreads - The number of thereads. 1 or 2. The default value is 2.
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Fast mode (algo = 0) can use only 1 thread.
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Out:
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destLen - processed output size
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Returns:
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SZ_OK - OK
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SZ_ERROR_MEM - Memory allocation error
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SZ_ERROR_PARAM - Incorrect paramater
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SZ_ERROR_OUTPUT_EOF - output buffer overflow
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SZ_ERROR_THREAD - errors in multithreading functions (only for Mt version)
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*/
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MY_STDAPI LzmaCompress(unsigned char *dest, size_t *destLen, const unsigned char *src, size_t srcLen,
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unsigned char *outProps, size_t *outPropsSize, /* *outPropsSize must be = 5 */
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int level, /* 0 <= level <= 9, default = 5 */
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unsigned dictSize, /* default = (1 << 24) */
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int lc, /* 0 <= lc <= 8, default = 3 */
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int lp, /* 0 <= lp <= 4, default = 0 */
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int pb, /* 0 <= pb <= 4, default = 2 */
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int fb, /* 5 <= fb <= 273, default = 32 */
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int numThreads /* 1 or 2, default = 2 */
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);
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/*
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LzmaUncompress
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--------------
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In:
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dest - output data
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destLen - output data size
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src - input data
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srcLen - input data size
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Out:
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destLen - processed output size
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srcLen - processed input size
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Returns:
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SZ_OK - OK
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SZ_ERROR_DATA - Data error
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SZ_ERROR_MEM - Memory allocation arror
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SZ_ERROR_UNSUPPORTED - Unsupported properties
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SZ_ERROR_INPUT_EOF - it needs more bytes in input buffer (src)
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*/
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MY_STDAPI LzmaUncompress(unsigned char *dest, size_t *destLen, const unsigned char *src, SizeT *srcLen,
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const unsigned char *props, size_t propsSize);
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#define LZMA_COMPRESS_FUNC_EXPORT "LzmaCompress"
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#define LZMA_UNCOMPRESS_FUNC_EXPORT "LzmaUncompress"
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}
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#endif
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