164 lines
3.8 KiB
C
164 lines
3.8 KiB
C
/* Ppmd8Enc.c -- PPMdI Encoder
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2010-04-16 : Igor Pavlov : Public domain
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This code is based on:
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PPMd var.I (2002): Dmitry Shkarin : Public domain
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Carryless rangecoder (1999): Dmitry Subbotin : Public domain */
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#include "Precomp.h"
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#include "Ppmd8.h"
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#define kTop (1 << 24)
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#define kBot (1 << 15)
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void Ppmd8_RangeEnc_FlushData(CPpmd8 *p)
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{
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unsigned i;
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for (i = 0; i < 4; i++, p->Low <<= 8 )
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p->Stream.Out->Write(p->Stream.Out, (Byte)(p->Low >> 24));
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}
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static void RangeEnc_Normalize(CPpmd8 *p)
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{
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while ((p->Low ^ (p->Low + p->Range)) < kTop ||
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(p->Range < kBot && ((p->Range = (0 - p->Low) & (kBot - 1)), 1)))
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{
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p->Stream.Out->Write(p->Stream.Out, (Byte)(p->Low >> 24));
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p->Range <<= 8;
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p->Low <<= 8;
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}
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}
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static void RangeEnc_Encode(CPpmd8 *p, UInt32 start, UInt32 size, UInt32 total)
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{
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p->Low += start * (p->Range /= total);
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p->Range *= size;
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RangeEnc_Normalize(p);
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}
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static void RangeEnc_EncodeBit_0(CPpmd8 *p, UInt32 size0)
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{
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p->Range >>= 14;
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p->Range *= size0;
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RangeEnc_Normalize(p);
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}
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static void RangeEnc_EncodeBit_1(CPpmd8 *p, UInt32 size0)
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{
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p->Low += size0 * (p->Range >>= 14);
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p->Range *= ((1 << 14) - size0);
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RangeEnc_Normalize(p);
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}
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#define MASK(sym) ((signed char *)charMask)[sym]
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void Ppmd8_EncodeSymbol(CPpmd8 *p, int symbol)
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{
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size_t charMask[256 / sizeof(size_t)];
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if (p->MinContext->NumStats != 0)
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{
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CPpmd_State *s = Ppmd8_GetStats(p, p->MinContext);
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UInt32 sum;
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unsigned i;
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if (s->Symbol == symbol)
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{
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RangeEnc_Encode(p, 0, s->Freq, p->MinContext->SummFreq);
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p->FoundState = s;
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Ppmd8_Update1_0(p);
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return;
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}
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p->PrevSuccess = 0;
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sum = s->Freq;
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i = p->MinContext->NumStats;
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do
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{
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if ((++s)->Symbol == symbol)
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{
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RangeEnc_Encode(p, sum, s->Freq, p->MinContext->SummFreq);
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p->FoundState = s;
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Ppmd8_Update1(p);
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return;
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}
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sum += s->Freq;
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}
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while (--i);
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PPMD_SetAllBitsIn256Bytes(charMask);
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MASK(s->Symbol) = 0;
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i = p->MinContext->NumStats;
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do { MASK((--s)->Symbol) = 0; } while (--i);
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RangeEnc_Encode(p, sum, p->MinContext->SummFreq - sum, p->MinContext->SummFreq);
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}
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else
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{
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UInt16 *prob = Ppmd8_GetBinSumm(p);
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CPpmd_State *s = Ppmd8Context_OneState(p->MinContext);
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if (s->Symbol == symbol)
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{
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RangeEnc_EncodeBit_0(p, *prob);
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*prob = (UInt16)PPMD_UPDATE_PROB_0(*prob);
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p->FoundState = s;
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Ppmd8_UpdateBin(p);
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return;
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}
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else
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{
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RangeEnc_EncodeBit_1(p, *prob);
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*prob = (UInt16)PPMD_UPDATE_PROB_1(*prob);
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p->InitEsc = PPMD8_kExpEscape[*prob >> 10];
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PPMD_SetAllBitsIn256Bytes(charMask);
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MASK(s->Symbol) = 0;
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p->PrevSuccess = 0;
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}
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}
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for (;;)
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{
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UInt32 escFreq;
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CPpmd_See *see;
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CPpmd_State *s;
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UInt32 sum;
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unsigned i, numMasked = p->MinContext->NumStats;
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do
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{
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p->OrderFall++;
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if (!p->MinContext->Suffix)
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return; /* EndMarker (symbol = -1) */
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p->MinContext = Ppmd8_GetContext(p, p->MinContext->Suffix);
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}
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while (p->MinContext->NumStats == numMasked);
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see = Ppmd8_MakeEscFreq(p, numMasked, &escFreq);
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s = Ppmd8_GetStats(p, p->MinContext);
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sum = 0;
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i = p->MinContext->NumStats + 1;
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do
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{
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int cur = s->Symbol;
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if (cur == symbol)
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{
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UInt32 low = sum;
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CPpmd_State *s1 = s;
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do
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{
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sum += (s->Freq & (int)(MASK(s->Symbol)));
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s++;
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}
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while (--i);
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RangeEnc_Encode(p, low, s1->Freq, sum + escFreq);
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Ppmd_See_Update(see);
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p->FoundState = s1;
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Ppmd8_Update2(p);
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return;
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}
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sum += (s->Freq & (int)(MASK(cur)));
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MASK(cur) = 0;
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s++;
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}
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while (--i);
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RangeEnc_Encode(p, sum, escFreq, sum + escFreq);
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see->Summ = (UInt16)(see->Summ + sum + escFreq);
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}
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}
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