1/* Ppmd7Enc.c -- PPMdH Encoder
  22010-03-12 : Igor Pavlov : Public domain
  3This code is based on PPMd var.H (2001): Dmitry Shkarin : Public domain */
  4
  5#include "Precomp.h"
  6
  7#include "Ppmd7.h"
  8
  9#define kTopValue (1 << 24)
 10
 11void Ppmd7z_RangeEnc_Init(CPpmd7z_RangeEnc *p)
 12{
 13  p->Low = 0;
 14  p->Range = 0xFFFFFFFF;
 15  p->Cache = 0;
 16  p->CacheSize = 1;
 17}
 18
 19static void RangeEnc_ShiftLow(CPpmd7z_RangeEnc *p)
 20{
 21  if ((UInt32)p->Low < (UInt32)0xFF000000 || (unsigned)(p->Low >> 32) != 0)
 22  {
 23    Byte temp = p->Cache;
 24    do
 25    {
 26      p->Stream->Write(p->Stream, (Byte)(temp + (Byte)(p->Low >> 32)));
 27      temp = 0xFF;
 28    }
 29    while(--p->CacheSize != 0);
 30    p->Cache = (Byte)((UInt32)p->Low >> 24);
 31  }
 32  p->CacheSize++;
 33  p->Low = (UInt32)p->Low << 8;
 34}
 35
 36static void RangeEnc_Encode(CPpmd7z_RangeEnc *p, UInt32 start, UInt32 size, UInt32 total)
 37{
 38  p->Low += start * (p->Range /= total);
 39  p->Range *= size;
 40  while (p->Range < kTopValue)
 41  {
 42    p->Range <<= 8;
 43    RangeEnc_ShiftLow(p);
 44  }
 45}
 46
 47static void RangeEnc_EncodeBit_0(CPpmd7z_RangeEnc *p, UInt32 size0)
 48{
 49  p->Range = (p->Range >> 14) * size0;
 50  while (p->Range < kTopValue)
 51  {
 52    p->Range <<= 8;
 53    RangeEnc_ShiftLow(p);
 54  }
 55}
 56
 57static void RangeEnc_EncodeBit_1(CPpmd7z_RangeEnc *p, UInt32 size0)
 58{
 59  UInt32 newBound = (p->Range >> 14) * size0;
 60  p->Low += newBound;
 61  p->Range -= newBound;
 62  while (p->Range < kTopValue)
 63  {
 64    p->Range <<= 8;
 65    RangeEnc_ShiftLow(p);
 66  }
 67}
 68
 69void Ppmd7z_RangeEnc_FlushData(CPpmd7z_RangeEnc *p)
 70{
 71  unsigned i;
 72  for (i = 0; i < 5; i++)
 73    RangeEnc_ShiftLow(p);
 74}
 75
 76
 77#define MASK(sym) ((signed char *)charMask)[sym]
 78
 79void Ppmd7_EncodeSymbol(CPpmd7 *p, CPpmd7z_RangeEnc *rc, int symbol)
 80{
 81  size_t charMask[256 / sizeof(size_t)];
 82  if (p->MinContext->NumStats != 1)
 83  {
 84    CPpmd_State *s = Ppmd7_GetStats(p, p->MinContext);
 85    UInt32 sum;
 86    unsigned i;
 87    if (s->Symbol == symbol)
 88    {
 89      RangeEnc_Encode(rc, 0, s->Freq, p->MinContext->SummFreq);
 90      p->FoundState = s;
 91      Ppmd7_Update1_0(p);
 92      return;
 93    }
 94    p->PrevSuccess = 0;
 95    sum = s->Freq;
 96    i = p->MinContext->NumStats - 1;
 97    do
 98    {
 99      if ((++s)->Symbol == symbol)
100      {
101        RangeEnc_Encode(rc, sum, s->Freq, p->MinContext->SummFreq);
102        p->FoundState = s;
103        Ppmd7_Update1(p);
104        return;
105      }
106      sum += s->Freq;
107    }
108    while (--i);
109    
110    p->HiBitsFlag = p->HB2Flag[p->FoundState->Symbol];
111    PPMD_SetAllBitsIn256Bytes(charMask);
112    MASK(s->Symbol) = 0;
113    i = p->MinContext->NumStats - 1;
114    do { MASK((--s)->Symbol) = 0; } while (--i);
115    RangeEnc_Encode(rc, sum, p->MinContext->SummFreq - sum, p->MinContext->SummFreq);
116  }
117  else
118  {
119    UInt16 *prob = Ppmd7_GetBinSumm(p);
120    CPpmd_State *s = Ppmd7Context_OneState(p->MinContext);
121    if (s->Symbol == symbol)
122    {
123      RangeEnc_EncodeBit_0(rc, *prob);
124      *prob = (UInt16)PPMD_UPDATE_PROB_0(*prob);
125      p->FoundState = s;
126      Ppmd7_UpdateBin(p);
127      return;
128    }
129    else
130    {
131      RangeEnc_EncodeBit_1(rc, *prob);
132      *prob = (UInt16)PPMD_UPDATE_PROB_1(*prob);
133      p->InitEsc = PPMD7_kExpEscape[*prob >> 10];
134      PPMD_SetAllBitsIn256Bytes(charMask);
135      MASK(s->Symbol) = 0;
136      p->PrevSuccess = 0;
137    }
138  }
139  for (;;)
140  {
141    UInt32 escFreq;
142    CPpmd_See *see;
143    CPpmd_State *s;
144    UInt32 sum;
145    unsigned i, numMasked = p->MinContext->NumStats;
146    do
147    {
148      p->OrderFall++;
149      if (!p->MinContext->Suffix)
150        return; /* EndMarker (symbol = -1) */
151      p->MinContext = Ppmd7_GetContext(p, p->MinContext->Suffix);
152    }
153    while (p->MinContext->NumStats == numMasked);
154    
155    see = Ppmd7_MakeEscFreq(p, numMasked, &escFreq);
156    s = Ppmd7_GetStats(p, p->MinContext);
157    sum = 0;
158    i = p->MinContext->NumStats;
159    do
160    {
161      int cur = s->Symbol;
162      if (cur == symbol)
163      {
164        UInt32 low = sum;
165        CPpmd_State *s1 = s;
166        do
167        {
168          sum += (s->Freq & (int)(MASK(s->Symbol)));
169          s++;
170        }
171        while (--i);
172        RangeEnc_Encode(rc, low, s1->Freq, sum + escFreq);
173        Ppmd_See_Update(see);
174        p->FoundState = s1;
175        Ppmd7_Update2(p);
176        return;
177      }
178      sum += (s->Freq & (int)(MASK(cur)));
179      MASK(cur) = 0;
180      s++;
181    }
182    while (--i);
183    
184    RangeEnc_Encode(rc, sum, escFreq, sum + escFreq);
185    see->Summ = (UInt16)(see->Summ + sum + escFreq);
186  }
187}