• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
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
132