internal bool decodeSymbol2(ModelPPM model)
{
long count;
int hiCnt, i = NumStats - model.NumMasked;
SEE2Context psee2c = makeEscFreq2(model, i);
RangeCoder coder = model.Coder;
// STATE* ps[256], ** pps=ps, * p=U.Stats-1;
State p = tempState1.Initialize(model.Heap);
State temp = tempState2.Initialize(model.Heap);
p.Address = freqData.GetStats() - State.Size;
int pps = 0;
hiCnt = 0;
do
{
do
{
p.IncrementAddress(); // p++;
}while (model.CharMask[p.Symbol] == model.EscCount);
hiCnt += p.Freq;
ps[pps++] = p.Address;
}while (--i != 0);
coder.SubRange.incScale(hiCnt);
count = coder.CurrentCount;
if (count >= coder.SubRange.Scale)
{
return(false);
}
pps = 0;
p.Address = ps[pps];
if (count < hiCnt)
{
hiCnt = 0;
while ((hiCnt += p.Freq) <= count)
{
p.Address = ps[++pps]; // p=*++pps;
}
coder.SubRange.HighCount = hiCnt;
coder.SubRange.LowCount = hiCnt - p.Freq;
psee2c.update();
update2(model, p.Address);
}
else
{
coder.SubRange.LowCount = hiCnt;
coder.SubRange.HighCount = coder.SubRange.Scale;
i = NumStats - model.NumMasked; // ->NumMasked;
pps--;
do
{
temp.Address = ps[++pps]; // (*++pps)
model.CharMask[temp.Symbol] = model.EscCount;
}while (--i != 0);
psee2c.incSumm((int)coder.SubRange.Scale);
model.NumMasked = NumStats;
}
return(true);
}
internal bool decodeInit(Unpack unpackRead, int escChar)
{
int MaxOrder = unpackRead.Char & 0xff;
bool reset = ((MaxOrder & 0x20) != 0);
int MaxMB = 0;
if (reset)
{
MaxMB = unpackRead.Char;
}
else
{
if (subAlloc.GetAllocatedMemory() == 0)
{
return(false);
}
}
if ((MaxOrder & 0x40) != 0)
{
escChar = unpackRead.Char;
unpackRead.PpmEscChar = escChar;
}
coder = new RangeCoder(unpackRead);
if (reset)
{
MaxOrder = (MaxOrder & 0x1f) + 1;
if (MaxOrder > 16)
{
MaxOrder = 16 + (MaxOrder - 16) * 3;
}
if (MaxOrder == 1)
{
subAlloc.stopSubAllocator();
return(false);
}
subAlloc.startSubAllocator(MaxMB + 1);
minContext = new PPMContext(Heap);
//medContext = new PPMContext(Heap);
maxContext = new PPMContext(Heap);
foundState = new State(Heap);
dummySEE2Cont = new SEE2Context();
for (int i = 0; i < 25; i++)
{
for (int j = 0; j < 16; j++)
{
SEE2Cont[i][j] = new SEE2Context();
}
}
startModelRare(MaxOrder);
}
return(minContext.Address != 0);
}
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);
}