/**
* Compute the alpha decay factor such that the weight of an entry with age 'targetAgeInSeconds' is targetWeight'
*/
public static double ComputeAlpha(double targetWeight, long targetAgeInSeconds)
{
ParameterCheck.Check(targetAgeInSeconds > 0, "targetAgeInSeconds must be > 0");
ParameterCheck.Check(targetWeight > 0 && targetWeight < 1, "targetWeight must be in range (0, 1)");
return(-Math.Log(targetWeight) / targetAgeInSeconds);
}
public void Merge(DecayCounter decayCounter)
{
if (decayCounter == null)
{
throw new ArgumentNullException("decayCounter");
}
ParameterCheck.Check(decayCounter.Alpha == this.Alpha, $"Expected decayCounter to have alpha {this.Alpha}, but was {decayCounter.Alpha}.");
lock (SyncRoot)
{
// if the landmark this counter is behind the other counter
if (this.LandmarkInSeconds < decayCounter.LandmarkInSeconds)
{
// rescale this counter to the other counter, and add
this.RescaleToNewLandmark(decayCounter.LandmarkInSeconds);
this.Count += decayCounter.Count;
}
else
{
// rescale the other counter and add
double OtherRescaledCount = decayCounter.Count / this.Weight(this.LandmarkInSeconds, decayCounter.LandmarkInSeconds);
this.Count += OtherRescaledCount;
}
}
}
public long ToBytes()
{
double Bytes = this.GetValue(DataSizeUnit.BYTE);
ParameterCheck.Check(Bytes <= Int64.MaxValue, "Size in bytes is too large to be represented in bytes as a long.");
return((long)Bytes);
}
/// <summary>
/// Creates a slice over the specified array range.
/// </summary>
/// <param name="base"></param>
/// <param name="offset">The array position at which the slice begins</param>
/// <param name="length">The number of array positions to include in the slice</param>
public Slice(byte[] @base, int offset, int length)
{
ParameterCheck.OutOfRange(offset < @base.Length && offset + length < @base.Length, "offset");
this.Base = @base ?? throw new ArgumentNullException("base");
this.Address = ARRAY_BYTE_BASE_OFFSET + offset;
this.Size = length;
this.RetainedSize = INSTANCE_SIZE + Marshal.SizeOf(@base);
this.Reference = (offset == 0 && length == @base.Length) ? COMPACT : NOT_COMPACT;
}
public static Slice Allocate(int capacity)
{
if (capacity == 0)
{
return(EMPTY_SLICE);
}
ParameterCheck.Check(capacity <= MAX_ARRAY_SIZE, $"Cannot allocate slice largert than {MAX_ARRAY_SIZE} bytes.");
return(new Slice(new byte[capacity]));
}