/// <summary>
/// Find a "relatively" unused disk element, but not the element just added.
/// </summary>
/// <returns>DiskElement.</returns>
private DiskElement FindRelativelyUnused()
{
IMetaData[] elements = DiskStore.SampleElements(_diskElements);
IMetaData element = LfuPolicy.LeastHit(elements, null);
return((DiskElement)element);
}
/// <summary>
/// Uses random numbers to sample the entire map.
/// </summary>
/// <param name="diskElements">Elements.</param>
/// <returns>An array of sampled elements.</returns>
private static IMetaData[] SampleElements(Dictionary <object, DiskElement> diskElements)
{
int[] offsets = LfuPolicy.GenerateRandomSample(diskElements.Count);
DiskElement[] elements = new DiskElement[offsets.Length];
Dictionary <object, DiskElement> .Enumerator enumerator = diskElements.GetEnumerator();
for (int i = 0; i < offsets.Length; i++)
{
for (int j = 0; j <= offsets[i]; j++)
{
enumerator.MoveNext();
}
elements[i] = enumerator.Current.Value;
}
return(elements);
}
