/// <summary>
/// Returns num of set bits within the specified recent history of the window
/// </summary>
/// <param name="recentHistLength">Length of the recent history (-1 means the whole available history)</param>
public int GetNumOfSetBits(int recentHistLength = -1)
{
if (recentHistLength > Capacity || recentHistLength < -1)
{
throw new ArgumentException($"Invalid buffPartSize {recentHistLength}.", "buffPartSize");
}
else if (recentHistLength == 0)
{
return(0);
}
else if (recentHistLength == -1)
{
return(NumOfSetBits);
}
else
{
int numOfSegments = recentHistLength / MaxBits + ((recentHistLength % MaxBits) > 0 ? 1 : 0);
int lastSegHighestBitIndex = (recentHistLength - ((numOfSegments - 1) * MaxBits)) - 1;
int counter = 0;
for (int i = 0; i < numOfSegments - 1; i++)
{
counter += _segBitCounter[i];
}
for (int i = 0; i <= lastSegHighestBitIndex; i++)
{
counter += Bitwise.GetBit(_buffSegments[numOfSegments - 1], i);
}
return(counter);
}
}
/// <summary>
/// Adds next bit value into the window content
/// </summary>
/// <param name="bit">Specifies whether the bit to be added is set or not</param>
public void AddNext(bool bit)
{
int lowestBitVal = bit ? 1 : 0;
NumOfSetBits += lowestBitVal;
for (int i = 0; i < _buffSegments.Length; i++)
{
if (i < _buffSegments.Length - 1)
{
int segHighestBitVal = Bitwise.GetBit(_buffSegments[i], BitMaxIndex);
_segBitCounter[i] -= segHighestBitVal;
_buffSegments[i] <<= 1;
_buffSegments[i] += (ulong)lowestBitVal;
_segBitCounter[i] += lowestBitVal;
lowestBitVal = segHighestBitVal;
}
else
{
int segHighestBitVal = Bitwise.GetBit(_buffSegments[i], _lastSegHighestBitIndex);
_segBitCounter[i] -= segHighestBitVal;
NumOfSetBits -= segHighestBitVal;
_buffSegments[i] = SetBit(_buffSegments[i], _lastSegHighestBitIndex, false);
_buffSegments[i] <<= 1;
_buffSegments[i] += (ulong)lowestBitVal;
_segBitCounter[i] += lowestBitVal;
}
}
if (BufferedHistLength < Capacity)
{
++BufferedHistLength;
}
return;
}
/// <summary>
/// Returns bit value at the specified index within the window
/// </summary>
/// <param name="bitIndex">Zero based index of the bit (0 is the recent bit)</param>
public int GetBit(int bitIndex)
{
if ((bitIndex + 1) > Capacity || bitIndex < 0)
{
throw new ArgumentException($"Invalid bitIndex {bitIndex}.", "bitIndex");
}
int recentHistLength = bitIndex + 1;
int numOfSegments = recentHistLength / MaxBits + ((recentHistLength % MaxBits) > 0 ? 1 : 0);
int lastSegHighestBitIndex = (recentHistLength - ((numOfSegments - 1) * MaxBits)) - 1;
return(Bitwise.GetBit(_buffSegments[numOfSegments - 1], lastSegHighestBitIndex));
}
