public void EncodeInRange(long value, int first, int last, double sum)
{
if (first >= last)
{
return;
}
double sumHalf = sum / 2;
double currentSum = 0;
for (int i = first; i <= last; i++)
{
ShannonItem item = values[i];
currentSum += item.probability;
if (item.value == value)
{
int halfIndex = GetHalfIndex(sumHalf, first, last);
if (i >= halfIndex)
{
inputOutput.WriteBit(true);
EncodeInRange(value, halfIndex, last, sumHalf);
return;
}
else
{
inputOutput.WriteBit(false);
EncodeInRange(value, first, halfIndex - 1, sumHalf);
return;
}
}
}
}
public int GetHalfIndex(double sumHalf, int first, int last)
{
long currentSum = 0;
for (int i = first; i <= last; i++)
{
ShannonItem item = values[i];
currentSum += item.probability;
if (currentSum > sumHalf)
{
if (i == first)
{
return(i + 1);
}
return(i);
}
}
throw new Exception("Half index not found");
}
