internal void decodeBinSymbol(ModelPPM model)
{
State rs = tempState1.Initialize(model.Heap);
rs.Address = oneState.Address; // State&
model.HiBitsFlag = model.getHB2Flag()[model.FoundState.Symbol];
int off1 = rs.Freq - 1;
int off2 = getArrayIndex(model, rs);
int bs = model.BinSumm[off1][off2];
if (model.Coder.GetCurrentShiftCount(ModelPPM.TOT_BITS) < bs)
{
model.FoundState.Address = rs.Address;
rs.IncrementFreq((rs.Freq < 128) ? 1 : 0);
model.Coder.SubRange.LowCount = 0;
model.Coder.SubRange.HighCount = bs;
bs = ((bs + ModelPPM.INTERVAL - getMean(bs, ModelPPM.PERIOD_BITS, 2)) & 0xffff);
model.BinSumm[off1][off2] = bs;
model.PrevSuccess = 1;
model.incRunLength(1);
}
else
{
model.Coder.SubRange.LowCount = bs;
bs = (bs - getMean(bs, ModelPPM.PERIOD_BITS, 2)) & 0xFFFF;
model.BinSumm[off1][off2] = bs;
model.Coder.SubRange.HighCount = ModelPPM.BIN_SCALE;
model.InitEsc = ExpEscape[Utility.URShift(bs, 10)];
model.NumMasked = 1;
model.CharMask[rs.Symbol] = model.EscCount;
model.PrevSuccess = 0;
model.FoundState.Address = 0;
}
//int a = 0;//TODO just 4 debugging
}
internal int getArrayIndex(ModelPPM Model, State rs)
{
PPMContext tempSuffix = getTempPPMContext(Model.SubAlloc.Heap);
tempSuffix.Address = getSuffix();
int ret = 0;
ret += Model.PrevSuccess;
ret += Model.getNS2BSIndx()[tempSuffix.NumStats - 1];
ret += Model.HiBitsFlag + 2 * Model.getHB2Flag()[rs.Symbol];
ret += ((Utility.URShift(Model.RunLength, 26)) & 0x20);
return(ret);
}
internal bool decodeSymbol1(ModelPPM model)
{
RangeCoder coder = model.Coder;
coder.SubRange.Scale = freqData.SummFreq;
State p = new State(model.Heap);
p.Address = freqData.GetStats();
int i, HiCnt;
long count = coder.CurrentCount;
if (count >= coder.SubRange.Scale)
{
return(false);
}
if (count < (HiCnt = p.Freq))
{
coder.SubRange.HighCount = HiCnt;
model.PrevSuccess = (2 * HiCnt > coder.SubRange.Scale) ? 1 : 0;
model.incRunLength(model.PrevSuccess);
HiCnt += 4;
model.FoundState.Address = p.Address;
model.FoundState.Freq = HiCnt;
freqData.IncrementSummFreq(4);
if (HiCnt > ModelPPM.MAX_FREQ)
{
rescale(model);
}
coder.SubRange.LowCount = 0;
return(true);
}
else
{
if (model.FoundState.Address == 0)
{
return(false);
}
}
model.PrevSuccess = 0;
int numStats = NumStats;
i = numStats - 1;
while ((HiCnt += p.IncrementAddress().Freq) <= count)
{
if (--i == 0)
{
model.HiBitsFlag = model.getHB2Flag()[model.FoundState.Symbol];
coder.SubRange.LowCount = HiCnt;
model.CharMask[p.Symbol] = model.EscCount;
model.NumMasked = numStats;
i = numStats - 1;
model.FoundState.Address = 0;
do
{
model.CharMask[p.DecrementAddress().Symbol] = model.EscCount;
}while (--i != 0);
coder.SubRange.HighCount = coder.SubRange.Scale;
return(true);
}
}
coder.SubRange.LowCount = HiCnt - p.Freq;
coder.SubRange.HighCount = HiCnt;
update1(model, p.Address);
return(true);
}