ce188d4d |
1 | /* Ppmd.h -- PPMD codec common code\r |
2 | 2016-05-16 : Igor Pavlov : Public domain\r |
3 | This code is based on PPMd var.H (2001): Dmitry Shkarin : Public domain */\r |
4 | \r |
5 | #ifndef __PPMD_H\r |
6 | #define __PPMD_H\r |
7 | \r |
8 | #include "CpuArch.h"\r |
9 | \r |
10 | EXTERN_C_BEGIN\r |
11 | \r |
12 | #ifdef MY_CPU_32BIT\r |
13 | #define PPMD_32BIT\r |
14 | #endif\r |
15 | \r |
16 | #define PPMD_INT_BITS 7\r |
17 | #define PPMD_PERIOD_BITS 7\r |
18 | #define PPMD_BIN_SCALE (1 << (PPMD_INT_BITS + PPMD_PERIOD_BITS))\r |
19 | \r |
20 | #define PPMD_GET_MEAN_SPEC(summ, shift, round) (((summ) + (1 << ((shift) - (round)))) >> (shift))\r |
21 | #define PPMD_GET_MEAN(summ) PPMD_GET_MEAN_SPEC((summ), PPMD_PERIOD_BITS, 2)\r |
22 | #define PPMD_UPDATE_PROB_0(prob) ((prob) + (1 << PPMD_INT_BITS) - PPMD_GET_MEAN(prob))\r |
23 | #define PPMD_UPDATE_PROB_1(prob) ((prob) - PPMD_GET_MEAN(prob))\r |
24 | \r |
25 | #define PPMD_N1 4\r |
26 | #define PPMD_N2 4\r |
27 | #define PPMD_N3 4\r |
28 | #define PPMD_N4 ((128 + 3 - 1 * PPMD_N1 - 2 * PPMD_N2 - 3 * PPMD_N3) / 4)\r |
29 | #define PPMD_NUM_INDEXES (PPMD_N1 + PPMD_N2 + PPMD_N3 + PPMD_N4)\r |
30 | \r |
31 | #pragma pack(push, 1)\r |
32 | /* Most compilers works OK here even without #pragma pack(push, 1), but some GCC compilers need it. */\r |
33 | \r |
34 | /* SEE-contexts for PPM-contexts with masked symbols */\r |
35 | typedef struct\r |
36 | {\r |
37 | UInt16 Summ; /* Freq */\r |
38 | Byte Shift; /* Speed of Freq change; low Shift is for fast change */\r |
39 | Byte Count; /* Count to next change of Shift */\r |
40 | } CPpmd_See;\r |
41 | \r |
42 | #define Ppmd_See_Update(p) if ((p)->Shift < PPMD_PERIOD_BITS && --(p)->Count == 0) \\r |
43 | { (p)->Summ <<= 1; (p)->Count = (Byte)(3 << (p)->Shift++); }\r |
44 | \r |
45 | typedef struct\r |
46 | {\r |
47 | Byte Symbol;\r |
48 | Byte Freq;\r |
49 | UInt16 SuccessorLow;\r |
50 | UInt16 SuccessorHigh;\r |
51 | } CPpmd_State;\r |
52 | \r |
53 | #pragma pack(pop)\r |
54 | \r |
55 | typedef\r |
56 | #ifdef PPMD_32BIT\r |
57 | CPpmd_State *\r |
58 | #else\r |
59 | UInt32\r |
60 | #endif\r |
61 | CPpmd_State_Ref;\r |
62 | \r |
63 | typedef\r |
64 | #ifdef PPMD_32BIT\r |
65 | void *\r |
66 | #else\r |
67 | UInt32\r |
68 | #endif\r |
69 | CPpmd_Void_Ref;\r |
70 | \r |
71 | typedef\r |
72 | #ifdef PPMD_32BIT\r |
73 | Byte *\r |
74 | #else\r |
75 | UInt32\r |
76 | #endif\r |
77 | CPpmd_Byte_Ref;\r |
78 | \r |
79 | #define PPMD_SetAllBitsIn256Bytes(p) \\r |
80 | { unsigned z; for (z = 0; z < 256 / sizeof(p[0]); z += 8) { \\r |
81 | p[z+7] = p[z+6] = p[z+5] = p[z+4] = p[z+3] = p[z+2] = p[z+1] = p[z+0] = ~(size_t)0; }}\r |
82 | \r |
83 | EXTERN_C_END\r |
84 | \r |
85 | #endif\r |