public static void TraverseIndexPath(
SelectionNode root,
IndexPath path,
bool realizeChildren,
Action <SelectionNode, IndexPath, int, int> nodeAction)
{
var node = root;
for (int depth = 0; depth < path.GetSize(); depth++)
{
int childIndex = path.GetAt(depth);
nodeAction(node, path, depth, childIndex);
if (depth < path.GetSize() - 1)
{
node = node.GetAt(childIndex, realizeChildren, path) !;
}
}
}
private static bool IsSubSet(IndexPath path, IndexPath subset)
{
var subsetSize = subset.GetSize();
if (path.GetSize() < subsetSize)
{
return(false);
}
for (int i = 0; i < subsetSize; i++)
{
if (path.GetAt(i) != subset.GetAt(i))
{
return(false);
}
}
return(true);
}
public static void TraverseRangeRealizeChildren(
SelectionNode root,
IndexPath start,
IndexPath end,
Action <TreeWalkNodeInfo> nodeAction)
{
var pendingNodes = new List <TreeWalkNodeInfo>();
var current = start;
// Build up the stack to account for the depth first walk up to the
// start index path.
TraverseIndexPath(
root,
start,
true,
(node, path, depth, childIndex) =>
{
var currentPath = StartPath(path, depth);
bool isStartPath = IsSubSet(start, currentPath);
bool isEndPath = IsSubSet(end, currentPath);
int startIndex = depth < start.GetSize() && isStartPath ? start.GetAt(depth) : 0;
int endIndex = depth < end.GetSize() && isEndPath ? end.GetAt(depth) : node.DataCount - 1;
for (int i = endIndex; i >= startIndex; i--)
{
var child = node.GetAt(i, true, end);
if (child != null)
{
var childPath = currentPath.CloneWithChildIndex(i);
pendingNodes.Add(new TreeWalkNodeInfo(child, childPath, node));
}
}
});
// From the start index path, do a depth first walk as long as the
// current path is less than the end path.
while (pendingNodes.Count > 0)
{
var info = pendingNodes.Last();
pendingNodes.RemoveAt(pendingNodes.Count - 1);
int depth = info.Path.GetSize();
bool isStartPath = IsSubSet(start, info.Path);
bool isEndPath = IsSubSet(end, info.Path);
int startIndex = depth < start.GetSize() && isStartPath?start.GetAt(depth) : 0;
int endIndex = depth < end.GetSize() && isEndPath?end.GetAt(depth) : info.Node.DataCount - 1;
for (int i = endIndex; i >= startIndex; i--)
{
var child = info.Node.GetAt(i, true, end);
if (child != null)
{
var childPath = info.Path.CloneWithChildIndex(i);
pendingNodes.Add(new TreeWalkNodeInfo(child, childPath, info.Node));
}
}
nodeAction(info);
if (info.Path.CompareTo(end) == 0)
{
// We reached the end index path. stop iterating.
break;
}
}
}
