protected double ByteEntropy(TParser parser)
{
long currentPosition = parser.Position;
#if DEBUG
long position = parser.Position;
#endif // DEBUG
double entropy = 0.0;
// Wrap the data reader
ByteStreamDataReader byteStreamDataReader = new ByteStreamDataReader(parser);
byteStreamDataReader.Position = this.Offset + 2;
long[] byteValueCountArray = new long[256];
long endOffset = this.Offset + this.Length;
while (byteStreamDataReader.Position < endOffset)
{
byteValueCountArray[byteStreamDataReader.GetByte()]++;
}
for (int byteIndex = 0; byteIndex < 256; byteIndex++)
{
double p = byteValueCountArray[byteIndex] / (double)this.Length;
if (p > 0.0)
{
entropy += -(double)(p * Math.Log(p, 2.0));
}
}
parser.Position = currentPosition;
#if DEBUG
Debug.Assert(parser.Position == position);
#endif // DEBUG
return(entropy);
}
protected ByteStreamParser(ByteStreamDataReader dataReader)
: base(dataReader)
{
DataReader = dataReader;
}