repo sync | baa3858 | 2013-07-26 17:53:31 -0700 | [diff] [blame] | 1 | /* Ppmd.h -- PPMD codec common code
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| 2 | 2010-03-12 : Igor Pavlov : Public domain
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| 3 | This code is based on PPMd var.H (2001): Dmitry Shkarin : Public domain */
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| 4 |
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| 5 | #ifndef __PPMD_H
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| 6 | #define __PPMD_H
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| 7 |
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| 8 | #include "Types.h"
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| 9 | #include "CpuArch.h"
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| 10 |
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| 11 | EXTERN_C_BEGIN
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| 12 |
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| 13 | #ifdef MY_CPU_32BIT
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| 14 | #define PPMD_32BIT
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| 15 | #endif
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| 16 |
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| 17 | #define PPMD_INT_BITS 7
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| 18 | #define PPMD_PERIOD_BITS 7
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| 19 | #define PPMD_BIN_SCALE (1 << (PPMD_INT_BITS + PPMD_PERIOD_BITS))
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| 20 |
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| 21 | #define PPMD_GET_MEAN_SPEC(summ, shift, round) (((summ) + (1 << ((shift) - (round)))) >> (shift))
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| 22 | #define PPMD_GET_MEAN(summ) PPMD_GET_MEAN_SPEC((summ), PPMD_PERIOD_BITS, 2)
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| 23 | #define PPMD_UPDATE_PROB_0(prob) ((prob) + (1 << PPMD_INT_BITS) - PPMD_GET_MEAN(prob))
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| 24 | #define PPMD_UPDATE_PROB_1(prob) ((prob) - PPMD_GET_MEAN(prob))
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| 25 |
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| 26 | #define PPMD_N1 4
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| 27 | #define PPMD_N2 4
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| 28 | #define PPMD_N3 4
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| 29 | #define PPMD_N4 ((128 + 3 - 1 * PPMD_N1 - 2 * PPMD_N2 - 3 * PPMD_N3) / 4)
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| 30 | #define PPMD_NUM_INDEXES (PPMD_N1 + PPMD_N2 + PPMD_N3 + PPMD_N4)
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| 31 |
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| 32 | /* SEE-contexts for PPM-contexts with masked symbols */
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| 33 | typedef struct
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| 34 | {
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| 35 | UInt16 Summ; /* Freq */
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| 36 | Byte Shift; /* Speed of Freq change; low Shift is for fast change */
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| 37 | Byte Count; /* Count to next change of Shift */
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| 38 | } CPpmd_See;
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| 39 |
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| 40 | #define Ppmd_See_Update(p) if ((p)->Shift < PPMD_PERIOD_BITS && --(p)->Count == 0) \
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| 41 | { (p)->Summ <<= 1; (p)->Count = (Byte)(3 << (p)->Shift++); }
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| 42 |
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| 43 | typedef struct
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| 44 | {
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| 45 | Byte Symbol;
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| 46 | Byte Freq;
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| 47 | UInt16 SuccessorLow;
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| 48 | UInt16 SuccessorHigh;
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| 49 | } CPpmd_State;
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| 50 |
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| 51 | typedef
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| 52 | #ifdef PPMD_32BIT
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| 53 | CPpmd_State *
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| 54 | #else
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| 55 | UInt32
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| 56 | #endif
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| 57 | CPpmd_State_Ref;
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| 58 |
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| 59 | typedef
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| 60 | #ifdef PPMD_32BIT
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| 61 | void *
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| 62 | #else
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| 63 | UInt32
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| 64 | #endif
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| 65 | CPpmd_Void_Ref;
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| 66 |
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| 67 | typedef
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| 68 | #ifdef PPMD_32BIT
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| 69 | Byte *
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| 70 | #else
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| 71 | UInt32
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| 72 | #endif
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| 73 | CPpmd_Byte_Ref;
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| 74 |
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| 75 | #define PPMD_SetAllBitsIn256Bytes(p) \
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| 76 | { unsigned i; for (i = 0; i < 256 / sizeof(p[0]); i += 8) { \
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| 77 | p[i+7] = p[i+6] = p[i+5] = p[i+4] = p[i+3] = p[i+2] = p[i+1] = p[i+0] = ~(size_t)0; }}
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| 78 |
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| 79 | EXTERN_C_END
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| 80 |
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| 81 | #endif
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