public void Initialize(Memory <byte> nodeStatesWorkBuffer, int nodeCount)
{
int workBufferSize = GetWorkBufferSize(nodeCount);
Debug.Assert(nodeStatesWorkBuffer.Length >= workBufferSize);
_nodeCount = nodeCount;
int edgeMatrixWorkBufferSize = EdgeMatrix.GetWorkBufferSize(nodeCount);
_discovered.Initialize(nodeStatesWorkBuffer.Slice(0, edgeMatrixWorkBufferSize), nodeCount);
_finished.Initialize(nodeStatesWorkBuffer.Slice(edgeMatrixWorkBufferSize, edgeMatrixWorkBufferSize), nodeCount);
nodeStatesWorkBuffer = nodeStatesWorkBuffer.Slice(edgeMatrixWorkBufferSize * 2);
_resultArray = SpanMemoryManager <int> .Cast(nodeStatesWorkBuffer.Slice(0, sizeof(int) * nodeCount));
nodeStatesWorkBuffer = nodeStatesWorkBuffer.Slice(sizeof(int) * nodeCount);
Memory <int> stackWorkBuffer = SpanMemoryManager <int> .Cast(nodeStatesWorkBuffer.Slice(0, Stack.CalcBufferSize(nodeCount *nodeCount)));
_stack.Reset(stackWorkBuffer, nodeCount * nodeCount);
}
public NodeStates()
{
_stack = new Stack();
_discovered = new EdgeMatrix();
_finished = new EdgeMatrix();
}
public static int GetWorkBufferSize(int nodeCount)
{
return(Stack.CalcBufferSize(nodeCount * nodeCount) + 0xC * nodeCount + 2 * EdgeMatrix.GetWorkBufferSize(nodeCount));
}
public bool Sort(EdgeMatrix edgeMatrix)
{
Reset();
if (_nodeCount <= 0)
{
return(true);
}
for (int i = 0; i < _nodeCount; i++)
{
if (GetState(i) == NodeState.Unknown)
{
_stack.Push(i);
}
while (_stack.GetCurrentCount() > 0)
{
int topIndex = _stack.Top();
NodeState topState = GetState(topIndex);
if (topState == NodeState.Discovered)
{
SetState(topIndex, NodeState.Finished);
PushTsortResult(topIndex);
_stack.Pop();
}
else if (topState == NodeState.Finished)
{
_stack.Pop();
}
else
{
if (topState == NodeState.Unknown)
{
SetState(topIndex, NodeState.Discovered);
}
for (int j = 0; j < edgeMatrix.GetNodeCount(); j++)
{
if (edgeMatrix.Connected(topIndex, j))
{
NodeState jState = GetState(j);
if (jState == NodeState.Unknown)
{
_stack.Push(j);
}
// Found a loop, reset and propagate rejection.
else if (jState == NodeState.Discovered)
{
Reset();
return(false);
}
}
}
}
}
}
return(true);
}