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/* Ppmd8Enc.c -- PPMdI Encoder
2010-04-16 : Igor Pavlov : Public domain
This code is based on:
PPMd var.I (2002): Dmitry Shkarin : Public domain
Carryless rangecoder (1999): Dmitry Subbotin : Public domain */
#include "Ppmd8.h"
#define kTop (1 << 24)
#define kBot (1 << 15)
void Ppmd8_RangeEnc_FlushData(CPpmd8 *p)
{
unsigned i;
for (i = 0; i < 4; i++, p->Low <<= 8 )
p->Stream.Out->Write(p->Stream.Out, (Byte)(p->Low >> 24));
}
static void RangeEnc_Normalize(CPpmd8 *p)
{
while ((p->Low ^ (p->Low + p->Range)) < kTop ||
(p->Range < kBot && ((p->Range = (0 - p->Low) & (kBot - 1)), 1)))
{
p->Stream.Out->Write(p->Stream.Out, (Byte)(p->Low >> 24));
p->Range <<= 8;
p->Low <<= 8;
}
}
static void RangeEnc_Encode(CPpmd8 *p, UInt32 start, UInt32 size, UInt32 total)
{
p->Low += start * (p->Range /= total);
p->Range *= size;
RangeEnc_Normalize(p);
}
static void RangeEnc_EncodeBit_0(CPpmd8 *p, UInt32 size0)
{
p->Range >>= 14;
p->Range *= size0;
RangeEnc_Normalize(p);
}
static void RangeEnc_EncodeBit_1(CPpmd8 *p, UInt32 size0)
{
p->Low += size0 * (p->Range >>= 14);
p->Range *= ((1 << 14) - size0);
RangeEnc_Normalize(p);
}
#define MASK(sym) ((signed char *)charMask)[sym]
void Ppmd8_EncodeSymbol(CPpmd8 *p, int symbol)
{
size_t charMask[256 / sizeof(size_t)];
if (p->MinContext->NumStats != 0)
{
CPpmd_State *s = Ppmd8_GetStats(p, p->MinContext);
UInt32 sum;
unsigned i;
if (s->Symbol == symbol)
{
RangeEnc_Encode(p, 0, s->Freq, p->MinContext->SummFreq);
p->FoundState = s;
Ppmd8_Update1_0(p);
return;
}
p->PrevSuccess = 0;
sum = s->Freq;
i = p->MinContext->NumStats;
do
{
if ((++s)->Symbol == symbol)
{
RangeEnc_Encode(p, sum, s->Freq, p->MinContext->SummFreq);
p->FoundState = s;
Ppmd8_Update1(p);
return;
}
sum += s->Freq;
}
while (--i);
PPMD_SetAllBitsIn256Bytes(charMask);
MASK(s->Symbol) = 0;
i = p->MinContext->NumStats;
do { MASK((--s)->Symbol) = 0; } while (--i);
RangeEnc_Encode(p, sum, p->MinContext->SummFreq - sum, p->MinContext->SummFreq);
}
else
{
UInt16 *prob = Ppmd8_GetBinSumm(p);
CPpmd_State *s = Ppmd8Context_OneState(p->MinContext);
if (s->Symbol == symbol)
{
RangeEnc_EncodeBit_0(p, *prob);
*prob = (UInt16)PPMD_UPDATE_PROB_0(*prob);
p->FoundState = s;
Ppmd8_UpdateBin(p);
return;
}
else
{
RangeEnc_EncodeBit_1(p, *prob);
*prob = (UInt16)PPMD_UPDATE_PROB_1(*prob);
p->InitEsc = PPMD8_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 = Ppmd8_GetContext(p, p->MinContext->Suffix);
}
while (p->MinContext->NumStats == numMasked);
see = Ppmd8_MakeEscFreq(p, numMasked, &escFreq);
s = Ppmd8_GetStats(p, p->MinContext);
sum = 0;
i = p->MinContext->NumStats + 1;
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(p, low, s1->Freq, sum + escFreq);
Ppmd_See_Update(see);
p->FoundState = s1;
Ppmd8_Update2(p);
return;
}
sum += (s->Freq & (int)(MASK(cur)));
MASK(cur) = 0;
s++;
}
while (--i);
RangeEnc_Encode(p, sum, escFreq, sum + escFreq);
see->Summ = (UInt16)(see->Summ + sum + escFreq);
}
}
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