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Ppmd7Enc.c
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Ppmd7Enc.c
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/* Ppmd7Enc.c -- PPMdH Encoder
2010-03-12 : Igor Pavlov : Public domain
This code is based on PPMd var.H (2001): Dmitry Shkarin : Public domain */
#include "Ppmd7.h"
#define kTopValue (1 << 24)
void Ppmd7z_RangeEnc_Init(CPpmd7z_RangeEnc *p)
{
p->Low = 0;
p->Range = 0xFFFFFFFF;
p->Cache = 0;
p->CacheSize = 1;
}
static void RangeEnc_ShiftLow(CPpmd7z_RangeEnc *p)
{
if ((UInt32)p->Low < (UInt32)0xFF000000 || (unsigned)(p->Low >> 32) != 0)
{
Byte temp = p->Cache;
do
{
p->Stream->Write(p->Stream, (Byte)(temp + (Byte)(p->Low >> 32)));
temp = 0xFF;
}
while(--p->CacheSize != 0);
p->Cache = (Byte)((UInt32)p->Low >> 24);
}
p->CacheSize++;
p->Low = (UInt32)p->Low << 8;
}
static void RangeEnc_Encode(CPpmd7z_RangeEnc *p, UInt32 start, UInt32 size, UInt32 total)
{
p->Low += start * (p->Range /= total);
p->Range *= size;
while (p->Range < kTopValue)
{
p->Range <<= 8;
RangeEnc_ShiftLow(p);
}
}
static void RangeEnc_EncodeBit_0(CPpmd7z_RangeEnc *p, UInt32 size0)
{
p->Range = (p->Range >> 14) * size0;
while (p->Range < kTopValue)
{
p->Range <<= 8;
RangeEnc_ShiftLow(p);
}
}
static void RangeEnc_EncodeBit_1(CPpmd7z_RangeEnc *p, UInt32 size0)
{
UInt32 newBound = (p->Range >> 14) * size0;
p->Low += newBound;
p->Range -= newBound;
while (p->Range < kTopValue)
{
p->Range <<= 8;
RangeEnc_ShiftLow(p);
}
}
void Ppmd7z_RangeEnc_FlushData(CPpmd7z_RangeEnc *p)
{
unsigned i;
for (i = 0; i < 5; i++)
RangeEnc_ShiftLow(p);
}
#define MASK(sym) ((signed char *)charMask)[sym]
void Ppmd7_EncodeSymbol(CPpmd7 *p, CPpmd7z_RangeEnc *rc, int symbol)
{
size_t charMask[256 / sizeof(size_t)];
if (p->MinContext->NumStats != 1)
{
CPpmd_State *s = Ppmd7_GetStats(p, p->MinContext);
UInt32 sum;
unsigned i;
if (s->Symbol == symbol)
{
RangeEnc_Encode(rc, 0, s->Freq, p->MinContext->SummFreq);
p->FoundState = s;
Ppmd7_Update1_0(p);
return;
}
p->PrevSuccess = 0;
sum = s->Freq;
i = p->MinContext->NumStats - 1;
do
{
if ((++s)->Symbol == symbol)
{
RangeEnc_Encode(rc, sum, s->Freq, p->MinContext->SummFreq);
p->FoundState = s;
Ppmd7_Update1(p);
return;
}
sum += s->Freq;
}
while (--i);
p->HiBitsFlag = p->HB2Flag[p->FoundState->Symbol];
PPMD_SetAllBitsIn256Bytes(charMask);
MASK(s->Symbol) = 0;
i = p->MinContext->NumStats - 1;
do { MASK((--s)->Symbol) = 0; } while (--i);
RangeEnc_Encode(rc, sum, p->MinContext->SummFreq - sum, p->MinContext->SummFreq);
}
else
{
UInt16 *prob = Ppmd7_GetBinSumm(p);
CPpmd_State *s = Ppmd7Context_OneState(p->MinContext);
if (s->Symbol == symbol)
{
RangeEnc_EncodeBit_0(rc, *prob);
*prob = (UInt16)PPMD_UPDATE_PROB_0(*prob);
p->FoundState = s;
Ppmd7_UpdateBin(p);
return;
}
else
{
RangeEnc_EncodeBit_1(rc, *prob);
*prob = (UInt16)PPMD_UPDATE_PROB_1(*prob);
p->InitEsc = PPMD7_kExpEscape[*prob >> 10];
PPMD_SetAllBitsIn256Bytes(charMask);
MASK(s->Symbol) = 0;
p->PrevSuccess = 0;
}
}
for (;;)
{
UInt32 escFreq;
CPpmd_See *see;
CPpmd_State *s;
UInt32 sum;
unsigned i, numMasked = p->MinContext->NumStats;
do
{
p->OrderFall++;
if (!p->MinContext->Suffix)
return; /* EndMarker (symbol = -1) */
p->MinContext = Ppmd7_GetContext(p, p->MinContext->Suffix);
}
while (p->MinContext->NumStats == numMasked);
see = Ppmd7_MakeEscFreq(p, numMasked, &escFreq);
s = Ppmd7_GetStats(p, p->MinContext);
sum = 0;
i = p->MinContext->NumStats;
do
{
int cur = s->Symbol;
if (cur == symbol)
{
UInt32 low = sum;
CPpmd_State *s1 = s;
do
{
sum += (s->Freq & (int)(MASK(s->Symbol)));
s++;
}
while (--i);
RangeEnc_Encode(rc, low, s1->Freq, sum + escFreq);
Ppmd_See_Update(see);
p->FoundState = s1;
Ppmd7_Update2(p);
return;
}
sum += (s->Freq & (int)(MASK(cur)));
MASK(cur) = 0;
s++;
}
while (--i);
RangeEnc_Encode(rc, sum, escFreq, sum + escFreq);
see->Summ = (UInt16)(see->Summ + sum + escFreq);
}
}

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Ppmd7Enc.c (4 KB)

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