private void printGivenLevel(RedBlackNode <TKey, TValue> node, int level)
{
if (node.IsSentinel)
{
Console.Write("null ");
return;
}
if (level == 1)
{
Console.Write($"{node.Key} ");
}
else if (level > 1)
{
printGivenLevel(node.Left, level - 1);
printGivenLevel(node.Right, level - 1);
}
}
private RedBlackNode <TKey, TValue> GetNode(TKey key)
{
// begin at root
RedBlackNode <TKey, TValue> treeNode = _root;
// traverse tree until node is found
while (!treeNode.IsSentinel)
{
var result = key.CompareTo(treeNode.Key);
if (result == 0)
{
return(treeNode);
}
treeNode = result < 0
? treeNode.Left
: treeNode.Right;
}
return(null);
}
private void RotateRight(RedBlackNode <TKey, TValue> rotateNode)
{
var workNode = rotateNode.Left;
rotateNode.Left = workNode.Right;
if (!workNode.Right.IsSentinel)
{
workNode.Right.Parent = rotateNode;
}
if (!workNode.IsSentinel)
{
workNode.Parent = rotateNode.Parent;
}
if (rotateNode.Parent != _dummy)
{
if (rotateNode == rotateNode.Parent.Right)
{
rotateNode.Parent.Right = workNode;
}
else
{
rotateNode.Parent.Left = workNode;
}
}
else
{
workNode.Parent = _dummy;
_dummy.Left = workNode;
_root = workNode;
}
workNode.Right = rotateNode;
if (!rotateNode.IsSentinel)
{
rotateNode.Parent = workNode;
}
}
private static int MaxDepthInternal(RedBlackNode <TKey, TValue> node)
{
if (node.IsSentinel)
{
return(0);
}
else
{
/* compute the depth of each subtree */
var lDepth = MaxDepthInternal(node.Left);
var rDepth = MaxDepthInternal(node.Right);
/* use the larger one */
if (lDepth > rDepth)
{
return(lDepth + 1);
}
else
{
return(rDepth + 1);
}
}
}
private bool setMarker(
List <RedBlackNode <TKey, TValue> > nodesToMark,
Guid pid,
RedBlackNode <TKey, TValue> z = null)
{
var nodesToUnMark = new List <RedBlackNode <TKey, TValue> >();
RedBlackNode <TKey, TValue> node;
for (var i = 0; i < 3; i++)
{
node = nodesToMark[i];
if (!SpacingRuleIsSatisfied(node, pid, true, z))
{
foreach (var n in nodesToUnMark)
{
n.Marker = Guid.Empty;
}
return(false);
}
node.Marker = pid;
nodesToUnMark.Add(node);
}
node = nodesToMark[3];
if (!SpacingRuleIsSatisfied(node, pid, false, z))
{
foreach (var n in nodesToUnMark)
{
n.Marker = Guid.Empty;
}
return(false);
}
node.Marker = pid;
return(true);
}
private bool IsIn(RedBlackNode <TKey, TValue> node, Guid pid)
{
List <MoveUpStruct <TKey, TValue> > moveUpStructList;
if (moveUpStructDict.ContainsKey(pid))
{
moveUpStructList = moveUpStructDict[pid];
}
else
{
return(false);
}
var moveUpStruct = moveUpStructList[moveUpStructList.Count - 1];
foreach (var n in moveUpStruct.Nodes)
{
if (node == n)
{
return(true);
}
}
return(false);
}
private void BalanceTreeAfterDelete(RedBlackNode <TKey, TValue> linkedNode)
{
// maintain Red-Black tree balance after deleting node
while (linkedNode != _root && linkedNode.Color == RedBlackNodeType.Black)
{
RedBlackNode <TKey, TValue> workNode;
// determine sub tree from parent
if (linkedNode == linkedNode.Parent.Left)
{
// y is x's sibling
workNode = linkedNode.Parent.Right;
if (workNode.Color == RedBlackNodeType.Red)
{
// x is black, y is red - make both black and rotate
linkedNode.Parent.Color = RedBlackNodeType.Red;
workNode.Color = RedBlackNodeType.Black;
RotateLeft(linkedNode.Parent);
workNode = linkedNode.Parent.Right;
}
if (workNode.Left.Color == RedBlackNodeType.Black &&
workNode.Right.Color == RedBlackNodeType.Black)
{
// children are both black
// change parent to red
workNode.Color = RedBlackNodeType.Red;
// move up the tree
linkedNode = linkedNode.Parent;
}
else
{
if (workNode.Right.Color == RedBlackNodeType.Black)
{
workNode.Left.Color = RedBlackNodeType.Black;
workNode.Color = RedBlackNodeType.Red;
RotateRight(workNode);
workNode = linkedNode.Parent.Right;
}
linkedNode.Parent.Color = RedBlackNodeType.Black;
workNode.Color = linkedNode.Parent.Color;
workNode.Right.Color = RedBlackNodeType.Black;
RotateLeft(linkedNode.Parent);
linkedNode = _root;
}
}
else
{ // right subtree - same as code above with right and left swapped
workNode = linkedNode.Parent.Left;
if (workNode.Color == RedBlackNodeType.Red)
{
linkedNode.Parent.Color = RedBlackNodeType.Red;
workNode.Color = RedBlackNodeType.Black;
RotateRight(linkedNode.Parent);
workNode = linkedNode.Parent.Left;
}
if (workNode.Right.Color == RedBlackNodeType.Black &&
workNode.Left.Color == RedBlackNodeType.Black)
{
workNode.Color = RedBlackNodeType.Red;
linkedNode = linkedNode.Parent;
}
else
{
if (workNode.Left.Color == RedBlackNodeType.Black)
{
workNode.Right.Color = RedBlackNodeType.Black;
workNode.Color = RedBlackNodeType.Red;
RotateLeft(workNode);
workNode = linkedNode.Parent.Left;
}
workNode.Color = linkedNode.Parent.Color;
linkedNode.Parent.Color = RedBlackNodeType.Black;
workNode.Left.Color = RedBlackNodeType.Black;
RotateRight(linkedNode.Parent);
linkedNode = _root;
}
}
}
linkedNode.Color = RedBlackNodeType.Black;
}
private void Delete(RedBlackNode <TKey, TValue> deleteNode)
{
// A node to be deleted will be:
// 1. a leaf with no children
// 2. have one child
// 3. have two children
// If the deleted node is red, the red black properties still hold.
// If the deleted node is black, the tree needs rebalancing
// work node
RedBlackNode <TKey, TValue> workNode;
// find the replacement node (the successor to x) - the node one with
// at *most* one child.
if (deleteNode.Left.IsSentinel || deleteNode.Right.IsSentinel)
{
// node has sentinel as a child
workNode = deleteNode;
}
else
{
// z has two children, find replacement node which will
// be the leftmost node greater than z
// traverse right subtree
workNode = deleteNode.Right;
// to find next node in sequence
while (!workNode.Left.IsSentinel)
{
workNode = workNode.Left;
}
}
// at this point, y contains the replacement node. it's content will be copied
// to the valules in the node to be deleted
// x (y's only child) is the node that will be linked to y's old parent.
RedBlackNode <TKey, TValue> linkedNode = !workNode.Left.IsSentinel
? workNode.Left
: workNode.Right;
// replace x's parent with y's parent and
// link x to proper subtree in parent
// this removes y from the chain
linkedNode.Parent = workNode.Parent;
if (workNode.Parent != null)
{
if (workNode == workNode.Parent.Left)
{
workNode.Parent.Left = linkedNode;
}
else
{
workNode.Parent.Right = linkedNode;
}
}
else
{
// make x the root node
_root = linkedNode;
}
// copy the values from y (the replacement node) to the node being deleted.
// note: this effectively deletes the node.
if (workNode != deleteNode)
{
deleteNode.Key = workNode.Key;
deleteNode.Data = workNode.Data;
}
if (workNode.Color == RedBlackNodeType.Black)
{
BalanceTreeAfterDelete(linkedNode);
}
}
private void BalanceTreeAfterInsert(RedBlackNode <TKey, TValue> insertedNode, List <RedBlackNode <TKey, TValue> > working)
{
// maintain red-black tree properties after adding newNode
while (insertedNode != _root && insertedNode.Parent.Color == RedBlackNodeType.Red)
{
RedBlackNode <TKey, TValue> workNode;
if (insertedNode.Parent == insertedNode.Parent.Parent.Left)
{
workNode = insertedNode.Parent.Parent.Right;
if (workNode != null && workNode.Color == RedBlackNodeType.Red)
{
insertedNode.Parent.Color = RedBlackNodeType.Black;
workNode.Color = RedBlackNodeType.Black;
insertedNode.Parent.Parent.Color = RedBlackNodeType.Red;
// continue loop with grandparent
insertedNode = insertedNode.Parent.Parent;
if (insertedNode == _root || insertedNode.Parent.Color != RedBlackNodeType.Red)
{
break;
}
MoveLocalAreaUpward(insertedNode, working);
}
else
{
if (insertedNode == insertedNode.Parent.Right)
{
insertedNode = insertedNode.Parent;
RotateLeft(insertedNode);
}
insertedNode.Parent.Color = RedBlackNodeType.Black;
insertedNode.Parent.Parent.Color = RedBlackNodeType.Red;
RotateRight(insertedNode.Parent.Parent);
}
}
else
{
workNode = insertedNode.Parent.Parent.Left;
if (workNode != null && workNode.Color == RedBlackNodeType.Red)
{
insertedNode.Parent.Color = RedBlackNodeType.Black;
workNode.Color = RedBlackNodeType.Black;
insertedNode.Parent.Parent.Color = RedBlackNodeType.Red;
// continue loop with grandparent
insertedNode = insertedNode.Parent.Parent;
if (insertedNode == _root || insertedNode.Parent.Color != RedBlackNodeType.Red)
{
break;
}
MoveLocalAreaUpward(insertedNode, working);
}
else
{
if (insertedNode == insertedNode.Parent.Left)
{
insertedNode = insertedNode.Parent;
RotateRight(insertedNode);
}
insertedNode.Parent.Color = RedBlackNodeType.Black;
insertedNode.Parent.Parent.Color = RedBlackNodeType.Red;
RotateLeft(insertedNode.Parent.Parent);
}
}
}
_root.Color = RedBlackNodeType.Black;
}
private (RedBlackNode <TKey, TValue>, bool) Insert(RedBlackNode <TKey, TValue> newNode)
{
RedBlackNode <TKey, TValue> aLocked;
RedBlackNode <TKey, TValue> lastBlack = null;
Monitor.Enter(rootLock);
RedBlackNode <TKey, TValue> workNode = _root;
workNode.GetALock();
if (workNode.IsSentinel)
{
// workNode is root
_root = newNode;
_root.GetALock();
workNode.ReleaseALock();
return(_root, true);
}
bool releaseRoot = true;
aLocked = workNode;
while (true)
{
if (workNode.IsSentinel)
{
break;
}
// find Parent
newNode.Parent = workNode;
int result = newNode.Key.CompareTo(workNode.Key);
if (result == 0)
{
throw new Exception("duplicate key");
}
if (workNode.Color == RedBlackNodeType.Black && lastBlack != _root)
{
if (lastBlack != null)
{
lastBlack.GetALock();
aLocked.ReleaseALock();
if (releaseRoot)
{
Monitor.Exit(rootLock);
}
aLocked = lastBlack;
releaseRoot = false;
}
lastBlack = workNode;
}
else
{
if (workNode.Color == RedBlackNodeType.Black)
{
lastBlack = workNode;
}
else
{
lastBlack = null;
}
}
if (result > 0)
{
workNode = workNode.Right;
}
else
{
workNode = workNode.Left;
}
}
if (newNode.Key.CompareTo(newNode.Parent.Key) > 0)
{
newNode.Parent.Right = newNode;
}
else
{
newNode.Parent.Left = newNode;
}
return(aLocked, releaseRoot);
}
private void FixUpCase1(
RedBlackNode <TKey, TValue>[] localArea,
Guid pid)
{
// correct relocated intention markers for other processes
if (localArea[2].Marker != Guid.Empty &&
localArea[3].Marker == localArea[2].Marker &&
localArea[1].Marker == Guid.Empty)
{
localArea[1].Marker = localArea[2].Marker;
localArea[2].Marker = Guid.Empty;
}
if (localArea[2].Marker != Guid.Empty &&
localArea[4].Marker == localArea[2].Marker &&
localArea[1].Marker == localArea[2].Marker)
{
Console.WriteLine("FixUpCase1: This should not happen!");
}
// Now correct local area and intention markers for the given process
// release highest held intention marker (fifth intention marker)
var intentionMarkers = new RedBlackNode <TKey, TValue> [4];
while (true)
{
if (GetFlagsForMarkers(localArea[2], pid, intentionMarkers, null))
{
break;
}
}
intentionMarkers[3].Marker = Guid.Empty;
ReleaseFlags(pid, false, intentionMarkers.ToList());
// release flag on node not "moved"
localArea[4].FreeNodeAtomically();
// acquire marker on old sibling of x and free the flag
localArea[2].Marker = pid;
localArea[2].FreeNodeAtomically();
RedBlackNode <TKey, TValue> neww = localArea[3];
RedBlackNode <TKey, TValue> newwl = neww.Left;
RedBlackNode <TKey, TValue> newwr = neww.Right;
if (!IsIn(newwl, pid))
{
while (true)
{
if (newwl.OccupyNodeAtomically())
{
break;
}
}
}
if (!IsIn(newwr, pid))
{
while (true)
{
if (newwr.OccupyNodeAtomically())
{
break;
}
}
}
localArea[2] = neww;
if (neww == localArea[1].Right)
{
localArea[3] = newwl;
localArea[4] = newwr;
}
else
{
localArea[3] = newwr;
localArea[4] = newwl;
}
}
private bool SpacingRuleIsSatisfied(
RedBlackNode <TKey, TValue> t,
Guid pid,
bool isParentOccupied,
RedBlackNode <TKey, TValue> z = null)
{
// we already hold flags on both t and z.
bool isMarkerAllowed = true;
// check that t has no marker set
if (z == null || z != t)
{
if (t.Marker != Guid.Empty)
{
return(false);
}
}
// check that t's parent has no flag or marker
RedBlackNode <TKey, TValue> tp = t.Parent;
if (z == null || z != tp)
{
if (!isParentOccupied)
{
if (!IsIn(tp, pid) && !tp.OccupyNodeAtomically())
{
return(false);
}
// verify parent is unchanged
if (tp != t.Parent)
{
tp.FreeNodeAtomically();
return(false);
}
}
if (tp.Marker != Guid.Empty)
{
if (!isParentOccupied)
{
tp.FreeNodeAtomically();
}
return(false);
}
}
//check that t's sibling has no flag or marker or PIDtoIgnore
var nodesToRelease = new List <RedBlackNode <TKey, TValue> >();
var ts = (t == tp.Left ? tp.Right : tp.Left);
if (!IsIn(ts, pid) && !ts.OccupyNodeAtomically())
{
if (z == null || z != tp)
{
if (!isParentOccupied)
{
nodesToRelease.Add(tp);
ReleaseFlags(pid, false, nodesToRelease);
}
}
return(false);
}
Guid PIDtoIgnore;
bool IsTooCloseProcess = getPIDtoIgnore(pid, out PIDtoIgnore);
if (ts.Marker != Guid.Empty && (!IsTooCloseProcess || ts.Marker != PIDtoIgnore))
{
isMarkerAllowed = false;
}
// release flags on ts and tp
nodesToRelease.Add(ts);
if (z == null || z != tp)
{
if (!isParentOccupied)
{
nodesToRelease.Add(tp);
}
}
ReleaseFlags(pid, false, nodesToRelease);
return(isMarkerAllowed);
}
private RedBlackNode <TKey, TValue> MoveDeleterUp(
RedBlackNode <TKey, TValue>[] localArea,
Guid pid)
{
// Check for a moveUpStruct from another process (due to Move-Up rule). Get direct pointers
// get old local area
RedBlackNode <TKey, TValue> oldx = localArea[0];
RedBlackNode <TKey, TValue> oldp = localArea[1];
RedBlackNode <TKey, TValue> oldw = localArea[2];
RedBlackNode <TKey, TValue> oldwlc = localArea[3];
RedBlackNode <TKey, TValue> oldwrc = localArea[4];
var newx = oldp;
localArea[0] = newx;
// Extend intention markers (getting flags to set them) by one more
// Also convert marker on oldgp to a flag i.e. set localArea[1] to oldgp
while (true)
{
if (GetFlagsAndMarkersAbove(oldp, localArea, pid, 1))
{
break;
}
}
// get flags on rest of the new local area (w, wlc, wrc)
var newp = newx.Parent;
var neww = newx == newp.Left ? newp.Right : newp.Left;
if (!IsIn(neww, pid))
{
while (true)
{
if (neww.OccupyNodeAtomically())
{
break;
}
}
}
var newwlc = neww.Left;
var newwrc = neww.Right;
if (!IsIn(newwlc, pid))
{
while (true)
{
if (newwlc.OccupyNodeAtomically())
{
break;
}
}
}
if (!IsIn(newwrc, pid))
{
while (true)
{
if (newwrc.OccupyNodeAtomically())
{
break;
}
}
}
localArea[2] = neww;
if (neww == localArea[1].Right)
{
localArea[3] = newwlc;
localArea[4] = newwrc;
}
else
{
localArea[3] = newwrc;
localArea[4] = newwlc;
}
// release flag on old local area
List <RedBlackNode <TKey, TValue> > nodesToRelease = new List <RedBlackNode <TKey, TValue> >();
nodesToRelease.Add(oldx);
nodesToRelease.Add(oldw);
nodesToRelease.Add(oldwlc);
nodesToRelease.Add(oldwrc);
ReleaseFlags(pid, true, nodesToRelease);
return(newx);
}
private bool GetFlagsAndMarkersAbove(
RedBlackNode <TKey, TValue> start,
RedBlackNode <TKey, TValue>[] localArea,
Guid pid,
int numAdditional,
RedBlackNode <TKey, TValue> z = null)
{
var markerPositions = new RedBlackNode <TKey, TValue> [4];
if (!GetFlagsForMarkers(start, pid, markerPositions, z))
{
return(false);
}
if (numAdditional == 0)
{
bool IsSetMarkerSuccess = setMarker(markerPositions.ToList(), pid, z);
// release flags on four nodes after putting markers
ReleaseFlags(pid, false, markerPositions.ToList());
return(IsSetMarkerSuccess);
}
var nodesToRelease = new List <RedBlackNode <TKey, TValue> >();
// get additional marker(s) above
RedBlackNode <TKey, TValue> firstnew = markerPositions[3].Parent;
if (!IsIn(firstnew, pid) && !firstnew.OccupyNodeAtomically())
{
nodesToRelease.Add(markerPositions[0]);
nodesToRelease.Add(markerPositions[1]);
nodesToRelease.Add(markerPositions[2]);
nodesToRelease.Add(markerPositions[3]);
ReleaseFlags(pid, false, nodesToRelease.ToList());
return(false);
}
if (firstnew != markerPositions[3].Parent && !SpacingRuleIsSatisfied(firstnew, pid, false, null))
{
nodesToRelease.Add(markerPositions[0]);
nodesToRelease.Add(markerPositions[1]);
nodesToRelease.Add(markerPositions[2]);
nodesToRelease.Add(markerPositions[3]);
nodesToRelease.Add(firstnew);
ReleaseFlags(pid, false, nodesToRelease.ToList());
return(false);
}
if (numAdditional == 1)
{
firstnew.Marker = pid;
nodesToRelease.Add(markerPositions[1]);
nodesToRelease.Add(markerPositions[2]);
nodesToRelease.Add(markerPositions[3]);
nodesToRelease.Add(firstnew);
localArea[1] = markerPositions[0];
markerPositions[0].Marker = Guid.Empty;
ReleaseFlags(pid, true, nodesToRelease);
return(true);;
}
if (numAdditional == 2)
{
// get additional marker above
RedBlackNode <TKey, TValue> secondnew = firstnew.Parent;
if (!IsIn(secondnew, pid) && !secondnew.OccupyNodeAtomically())
{
nodesToRelease.Add(markerPositions[0]);
nodesToRelease.Add(markerPositions[1]);
nodesToRelease.Add(markerPositions[2]);
nodesToRelease.Add(markerPositions[3]);
nodesToRelease.Add(firstnew);
ReleaseFlags(pid, false, nodesToRelease.ToList());
return(false);
}
if (secondnew != firstnew.Parent && !SpacingRuleIsSatisfied(secondnew, pid, false, null))
{
nodesToRelease.Add(markerPositions[0]);
nodesToRelease.Add(markerPositions[1]);
nodesToRelease.Add(markerPositions[2]);
nodesToRelease.Add(markerPositions[3]);
nodesToRelease.Add(firstnew);
nodesToRelease.Add(secondnew);
ReleaseFlags(pid, false, nodesToRelease.ToList());
return(false);
}
firstnew.Marker = pid;
secondnew.Marker = pid;
nodesToRelease.Add(markerPositions[2]);
nodesToRelease.Add(markerPositions[3]);
nodesToRelease.Add(firstnew);
nodesToRelease.Add(secondnew);
markerPositions[0].Marker = Guid.Empty;
markerPositions[1].Marker = Guid.Empty;
ReleaseFlags(pid, true, nodesToRelease);
return(true);;
}
return(true);
}
public RedBlackNode <TKey, TValue> Search(TKey key)
{
while (true)
{
if (_root == null)
{
break;
}
// begin at root
RedBlackNode <TKey, TValue> workNode = _root, nextNode = _root;
while (true)
{
if (!workNode.OccupyNodeAtomically())
{
continue;
}
int result = key.CompareTo(workNode.Key);
if (result == 0)
{
return(workNode);
}
if (result > 0)
{
nextNode = workNode.Right;
}
else
{
nextNode = workNode.Left;
}
if (nextNode.IsSentinel)
{
break;
}
if (!nextNode.OccupyNodeAtomically())
{
workNode.FreeNodeAtomically();
break;
}
if (nextNode.Parent != workNode)
{
workNode.FreeNodeAtomically();
nextNode.FreeNodeAtomically();
continue;
}
workNode.FreeNodeAtomically();
workNode = nextNode;
}
if (nextNode.IsSentinel)
{
break;
}
}
return(null);
}
private void BalanceTreeAfterDelete(
RedBlackNode <TKey, TValue> x,
RedBlackNode <TKey, TValue>[] localArea,
Guid pid)
{
bool done = false, didMoveUp = false;
// maintain Red-Black tree balance after deleting node
while (x != _root && x.Color == RedBlackNodeType.Black && !done)
{
RedBlackNode <TKey, TValue> w;
// determine sub tree from parent
if (x == x.Parent.Left)
{
w = x.Parent.Right;
if (w.Color == RedBlackNodeType.Red)
{
x.Parent.Color = RedBlackNodeType.Red;
w.Color = RedBlackNodeType.Black;
RotateLeft(x.Parent);
w = x.Parent.Right;
FixUpCase1(localArea, pid);
}
if (w.Left.Color == RedBlackNodeType.Black &&
w.Right.Color == RedBlackNodeType.Black)
{
// children are both black
// change parent to red
w.Color = RedBlackNodeType.Red;
// move up the tree
x = MoveDeleterUp(localArea, pid);
}
else
{
if (w.Right.Color == RedBlackNodeType.Black)
{
w.Left.Color = RedBlackNodeType.Black;
w.Color = RedBlackNodeType.Red;
RotateRight(w);
FixUpCase3(localArea, pid);
w = x.Parent.Right;
}
w.Color = x.Parent.Color;
x.Parent.Color = RedBlackNodeType.Black;
w.Right.Color = RedBlackNodeType.Black;
RotateLeft(x.Parent);
didMoveUp = ApplyMoveUpRule(localArea, pid);
done = true;
}
}
else
{ // right subtree - same as code above with right and left swapped
w = x.Parent.Left;
if (w.Color == RedBlackNodeType.Red)
{
x.Parent.Color = RedBlackNodeType.Red;
w.Color = RedBlackNodeType.Black;
RotateRight(x.Parent);
w = x.Parent.Left;
FixUpCase1(localArea, pid);
}
if (w.Right.Color == RedBlackNodeType.Black &&
w.Left.Color == RedBlackNodeType.Black)
{
w.Color = RedBlackNodeType.Red;
x = MoveDeleterUp(localArea, pid);
}
else
{
if (w.Left.Color == RedBlackNodeType.Black)
{
w.Right.Color = RedBlackNodeType.Black;
w.Color = RedBlackNodeType.Red;
RotateLeft(w);
FixUpCase3(localArea, pid);
w = x.Parent.Left;
}
w.Color = x.Parent.Color;
x.Parent.Color = RedBlackNodeType.Black;
w.Left.Color = RedBlackNodeType.Black;
RotateRight(x.Parent);
didMoveUp = ApplyMoveUpRule(localArea, pid);
done = true;
}
}
}
if (!didMoveUp)
{
x.Color = RedBlackNodeType.Black;
// release markers on local area
var intentionMarkers = new RedBlackNode <TKey, TValue> [4];
var localAreaTopNode = (localArea[1].Parent == localArea[2]) ? localArea[2] : localArea[1];
while (true)
{
if (GetFlagsForMarkers(localAreaTopNode, pid, intentionMarkers, null))
{
break;
}
}
foreach (var node in intentionMarkers)
{
node.Marker = Guid.Empty;
}
ReleaseFlags(pid, false, intentionMarkers.ToList());
// correct relocated intention markers for other processes
if (localArea[2].Marker != Guid.Empty &&
localArea[3].Marker == localArea[2].Marker &&
localArea[1].Marker == Guid.Empty)
{
localArea[1].Marker = localArea[2].Marker;
localArea[2].Marker = Guid.Empty;
}
if (localArea[2].Marker != Guid.Empty &&
localArea[4].Marker == localArea[2].Marker &&
localArea[1].Marker == localArea[2].Marker)
{
Console.WriteLine("FixUpCase4: This should not happen!");
while (true)
{
if (localArea[2].Parent.OccupyNodeAtomically())
{
break;
}
}
localArea[2].Parent.Marker = localArea[2].Marker;
localArea[2].Parent.FreeNodeAtomically();
}
// release flags on local area
foreach (var node in localArea)
{
node?.FreeNodeAtomically();
}
}
}
private bool SetupLocalAreaForDelete(
RedBlackNode <TKey, TValue> y,
RedBlackNode <TKey, TValue>[] localArea,
Guid pid,
RedBlackNode <TKey, TValue> z = null)
{
var x = y.Left.IsSentinel ? y.Right : y.Left;
// occupy the node which will replace y
if (!x.OccupyNodeAtomically())
{
return(false);
}
localArea[0] = x;
var yp = y.Parent;
bool isNotCheckZ = (z == null || yp != z);
if (isNotCheckZ && !yp.OccupyNodeAtomically())
{
x.FreeNodeAtomically();
return(false);
}
// verify that parent is unchanged
if (yp != y.Parent)
{
x.FreeNodeAtomically();
if (isNotCheckZ)
{
yp.FreeNodeAtomically();
}
return(false);
}
localArea[1] = yp;
var w = (y == yp.Left ? yp.Right : yp.Left);
if (!w.OccupyNodeAtomically())
{
x.FreeNodeAtomically();
if (isNotCheckZ)
{
yp.FreeNodeAtomically();
}
return(false);
}
// verify if sibling is changed
var nw = (y == yp.Left ? yp.Right : yp.Left);
if (w != nw)
{
x.FreeNodeAtomically();
w.FreeNodeAtomically();
if (isNotCheckZ)
{
yp.FreeNodeAtomically();
}
return(false);
}
localArea[2] = w;
var wlc = w.Left;
var wrc = w.Right;
if (!w.IsSentinel)
{
if (!wlc.OccupyNodeAtomically())
{
x.FreeNodeAtomically();
w.FreeNodeAtomically();
if (isNotCheckZ)
{
yp.FreeNodeAtomically();
}
return(false);
}
// validate
if (w.Left != wlc)
{
x.FreeNodeAtomically();
w.FreeNodeAtomically();
wlc.FreeNodeAtomically();
if (isNotCheckZ)
{
yp.FreeNodeAtomically();
}
return(false);
}
if (!wrc.OccupyNodeAtomically())
{
x.FreeNodeAtomically();
w.FreeNodeAtomically();
wlc.FreeNodeAtomically();
if (isNotCheckZ)
{
yp.FreeNodeAtomically();
}
return(false);
}
// validate
if (w.Right != wrc)
{
x.FreeNodeAtomically();
w.FreeNodeAtomically();
wlc.FreeNodeAtomically();
wrc.FreeNodeAtomically();
if (isNotCheckZ)
{
yp.FreeNodeAtomically();
}
return(false);
}
if (w == yp.Right)
{
localArea[3] = wlc;
localArea[4] = wrc;
}
else
{
localArea[3] = wrc;
localArea[4] = wlc;
}
}
if (!GetFlagsAndMarkersAbove(yp, localArea, pid, 0, z))
{
x.FreeNodeAtomically();
w.FreeNodeAtomically();
if (!w.IsSentinel)
{
wlc.FreeNodeAtomically();
wrc.FreeNodeAtomically();
}
if (isNotCheckZ)
{
yp.FreeNodeAtomically();
}
return(false);
}
return(true);
}
private bool ApplyMoveUpRule(
RedBlackNode <TKey, TValue>[] localArea,
Guid pid)
{
// Check in our local area to see if two processes beneath
// use have been brought too close together by our rotations.
// The three cases correspond to Figures 17, 18 and 19.
var w = localArea[4];
var wChild_p1 = w.Right;
var wChild_p2 = w.Left;
if (w == w.Parent.Left)
{
wChild_p1 = w.Left;
wChild_p2 = w.Right;
}
var case1 = w.Marker == w.Parent.Marker &&
w.Marker == wChild_p1.Marker &&
w.Marker != Guid.Empty &&
wChild_p2.Marker != Guid.Empty;
var case2 = wChild_p1.Marker == w.Marker &&
w.Marker != Guid.Empty &&
wChild_p2.Marker != Guid.Empty;
var case3 = w.Marker == Guid.Empty &&
wChild_p1.Marker != Guid.Empty &&
wChild_p2.Marker != Guid.Empty;
if (case1 || case2 || case3)
{
Console.WriteLine("case1 || case2 || case3");
// Let pid release their markers ??????????? or pass their markers as well?????
var intentionMarkers = new RedBlackNode <TKey, TValue> [4];
while (true)
{
if (GetFlagsForMarkers(w.Parent, pid, intentionMarkers, null))
{
break;
}
}
foreach (var node in intentionMarkers)
{
node.Marker = Guid.Empty;
}
ReleaseFlags(pid, false, intentionMarkers.ToList());
// Build structure listing the nodes we hold flags on
// (moveUpStruct) and specifying the PID of the other
// "too-close" process (marker[left[w]) and the goal (GP).
// Make structure available to process id: marker[right[w]]
var newMoveUpStruct = new MoveUpStruct <TKey, TValue>();
newMoveUpStruct.Nodes.Add(localArea[0]);
newMoveUpStruct.Nodes.Add(localArea[1]);
newMoveUpStruct.Nodes.Add(localArea[2]); // top node
newMoveUpStruct.Nodes.Add(localArea[3]);
newMoveUpStruct.Nodes.Add(localArea[4]);
newMoveUpStruct.PidToIgnore = wChild_p2.Marker;
// newMoveUpStruct.Gp = w.Parent.Parent ???????????? Gp is not locked, what if it changes
var inheritedMoveUpStructs = new List <MoveUpStruct <TKey, TValue> >();
if (moveUpStructDict.ContainsKey(pid))
{
inheritedMoveUpStructs = moveUpStructDict[pid];
}
inheritedMoveUpStructs.Add(newMoveUpStruct);
moveUpStructDict.TryAdd(wChild_p1.Marker, inheritedMoveUpStructs);
}
return(false);
}
private bool OccupyLocalAreaForInsert(RedBlackNode <TKey, TValue> node, RedBlackNode <TKey, TValue>[] localArea, Guid pid)
{
// occupy the node to be inserted
if (!node.OccupyNodeAtomically())
{
node.Parent.FreeNodeAtomically();
return(false);
}
var grandParent = node.Parent.Parent;
// occupy grandparent
if (!grandParent.OccupyNodeAtomically())
{
node.Parent.FreeNodeAtomically();
node.FreeNodeAtomically();
return(false);
}
// if grand parent changed before occupying, return false
if (grandParent != node.Parent.Parent)
{
// free grand parent
grandParent.FreeNodeAtomically();
node.Parent.FreeNodeAtomically();
node.FreeNodeAtomically();
return(false);
}
var uncle = grandParent.Left == node.Parent ? grandParent.Right : grandParent.Left;
if (!uncle.OccupyNodeAtomically())
{
grandParent.FreeNodeAtomically();
node.Parent.FreeNodeAtomically();
node.FreeNodeAtomically();
return(false);
}
//check if uncle is not changed
var temp_uncle = (grandParent.Left == node.Parent ? grandParent.Right : grandParent.Left);
if (uncle != temp_uncle)
{
uncle.FreeNodeAtomically();
grandParent.FreeNodeAtomically();
node.Parent.FreeNodeAtomically();
node.FreeNodeAtomically();
return(false);
}
localArea[0] = node;
localArea[1] = node.Parent;
localArea[2] = grandParent;
localArea[3] = uncle;
if (!GetFlagsAndMarkersAbove(grandParent, localArea, pid, 0))
{
uncle.FreeNodeAtomically();
grandParent.FreeNodeAtomically();
node.Parent.FreeNodeAtomically();
node.FreeNodeAtomically();
return(false);
}
return(true);
}
private bool Delete(TKey key, Guid pid)
{
RedBlackNode <TKey, TValue> y = null, z = null, x = null;
var localArea = new RedBlackNode <TKey, TValue> [5];
while (true)
{
// GetNode will return a locked node
z = GetNodeForDelete(key);
if (z == null)
{
continue;
}
// Find key-order successor, locked y is returned
y = FindSuccessor(z);
if (y == null)
{
//Console.WriteLine("No successor");
z.FreeNodeAtomically();
continue;
}
//we now hold a flag on y and z
if (!SetupLocalAreaForDelete(y, localArea, pid, z))
{
y.FreeNodeAtomically();
if (y != z)
{
z.FreeNodeAtomically();
}
continue;
}
else
{
break;
}
}
x = y.Left.IsSentinel ? y.Right : y.Left;
// unlink y from the tree
x.Parent = y.Parent;
if (y.Parent != null)
{
if (y == y.Parent.Left)
{
y.Parent.Left = x;
}
else
{
y.Parent.Right = x;
}
}
else
{
_root = x;
}
// copy the values from y (the replacement node) to the node being deleted.
// note: this effectively deletes the node.
if (y != z)
{
z.Key = y.Key;
z.Data = y.Data;
// Release z only when it is not in local area
bool isZinLocalArea = false;
foreach (var node in localArea)
{
if (node == z)
{
isZinLocalArea = true;
break;
}
}
if (!isZinLocalArea)
{
z.FreeNodeAtomically();
}
y.FreeNodeAtomically();
}
if (y.Color == RedBlackNodeType.Black)
{
BalanceTreeAfterDelete(x, localArea, pid);
}
else
{
// Release markers of local area
var intentionMarkers = new RedBlackNode <TKey, TValue> [4];
while (true)
{
if (GetFlagsForMarkers(localArea[1], pid, intentionMarkers, z))
{
break;
}
}
foreach (var node in intentionMarkers)
{
node.Marker = Guid.Empty;
}
ReleaseFlags(pid, false, intentionMarkers.ToList());
// Release flags of local area
foreach (var node in localArea)
{
node?.FreeNodeAtomically();
}
}
return(true);
}
private void Insert(RedBlackNode <TKey, TValue> newNode, RedBlackNode <TKey, TValue>[] localArea, Guid pid)
{
while (true)
{
if (_root == null)
{
if (!_dummy.OccupyNodeAtomically())
{
continue;
}
if (!_dummy.Left.IsSentinel)
{
_dummy.FreeNodeAtomically();
continue;
}
newNode.OccupyNodeAtomically();
// first node added
newNode.Parent = _dummy;
_dummy.Left = newNode;
_root = newNode;
break;
}
RedBlackNode <TKey, TValue> workNode = _root, nextNode = _root;
if (!workNode.OccupyNodeAtomically())
{
continue;
}
var isLocalAreaOccupied = false;
while (true)
{
newNode.Parent = workNode;
int result = newNode.Key.CompareTo(workNode.Key);
if (result == 0)
{
throw new Exception("duplicate key");
}
if (result > 0)
{
nextNode = workNode.Right;
}
else
{
nextNode = workNode.Left;
}
if (nextNode.IsSentinel)
{
isLocalAreaOccupied = OccupyLocalAreaForInsert(newNode, localArea, pid);
break;
}
if (!nextNode.OccupyNodeAtomically())
{
workNode.FreeNodeAtomically();
break;
}
if (nextNode.Parent != workNode)
{
workNode.FreeNodeAtomically();
nextNode.FreeNodeAtomically();
break;
}
workNode.FreeNodeAtomically();
workNode = nextNode;
}
if (isLocalAreaOccupied)
{
break;
}
}
// insert node into tree starting at parent's location
if (newNode != _root)
{
if (newNode.Key.CompareTo(newNode.Parent.Key) > 0)
{
newNode.Parent.Right = newNode;
}
else
{
newNode.Parent.Left = newNode;
}
}
}
private void MoveLocalAreaUpwardForInsert(RedBlackNode <TKey, TValue> node, RedBlackNode <TKey, TValue>[] working, Guid pid)
{
while (true)
{
if (GetFlagsAndMarkersAbove(node, working, pid, 2))
{
break;
}
}
RedBlackNode <TKey, TValue> newParent = node.Parent, newGrandParent = node.Parent.Parent, newUncle = null;
while (true)
{
newUncle = newGrandParent.Left == node.Parent ? newGrandParent.Right : newGrandParent.Left;
if (!IsIn(newUncle, pid))
{
if (newUncle.OccupyNodeAtomically())
{
//check if uncle is not changed
var temp_uncle = newGrandParent.Left == node.Parent ? newGrandParent.Right : newGrandParent.Left;
if (newUncle != temp_uncle)
{
newUncle.FreeNodeAtomically();
}
else
{
break;
}
}
}
else
{
break;
}
}
// release flag on old local area
List <RedBlackNode <TKey, TValue> > nodesToRelease = new List <RedBlackNode <TKey, TValue> >();
nodesToRelease.Add(working[0]);
nodesToRelease.Add(working[1]);
nodesToRelease.Add(working[3]);
ReleaseFlags(pid, true, nodesToRelease);
working[0] = node;
working[1] = newParent;
working[2] = newGrandParent;
working[3] = newUncle;
}