public void Execute()
{
var length = IndexedSourceBuffer.Length;
if (length == 0)
{
return;
}
var segmentCount = (length + (SegmentWidth - 1)) / SegmentWidth;
var segmentIndex = stackalloc int[segmentCount];
var lastSharedIndex = -1;
var lastSharedValue = default(T);
for (int sortIndex = 0; sortIndex < length; sortIndex++)
{
// find next best
int bestSegmentIndex = -1;
IndexedValue <T> bestValue = default(IndexedValue <T>);
for (int i = 0; i < segmentCount; i++)
{
var startIndex = i * SegmentWidth;
var offset = segmentIndex[i];
var segmentLength = ((length - startIndex) < SegmentWidth) ? (length - startIndex) : SegmentWidth;
if (offset == segmentLength)
{
continue;
}
var nextValue = IndexedSourceBuffer[startIndex + offset];
if (bestSegmentIndex != -1)
{
if (nextValue.CompareTo(bestValue) > 0)
{
continue;
}
}
bestValue = nextValue;
bestSegmentIndex = i;
}
segmentIndex[bestSegmentIndex]++;
SourceIndexBySortedSourceIndex[sortIndex] = bestValue.Index;
if ((lastSharedIndex != -1) && (bestValue.Value.CompareTo(lastSharedValue) == 0))
{
SharedIndexCountsBySharedIndex[lastSharedIndex]++;
}
else
{
lastSharedIndex++;
lastSharedValue = bestValue.Value;
SortedSourceIndexBySharedIndex.Add(sortIndex);
SharedIndexCountsBySharedIndex.Add(1);
}
SharedIndicesBySourceIndex[bestValue.Index] = lastSharedIndex;
}
}
public int CompareTo(IndexedValue <T> other) => Value.CompareTo(other.Value);
