/// <summary>
/// Gets the entry at counter position.
/// </summary>
/// <param name="start">The start.</param>
/// <param name="searchPosition">The search position.</param>
/// <param name="cookie">The cookie.</param>
/// <param name="preferLeftMost">if set to <c>true</c> prefer left most.</param>
/// <returns></returns>
TreeTableWithCounterEntry GetEntryAtCounterPosition(ITreeTableCounter start, ITreeTableCounter searchPosition, int cookie, bool preferLeftMost)
{
int treeNodeCount = GetCount();
//if (searchPosition < 0 || searchPosition >= VisibleCount)
if (searchPosition.Compare(GetStartCounterPosition(), cookie) < 0)
{
throw new ArgumentOutOfRangeException("searchPosition");
}
if (searchPosition.Compare(GetCounterTotal(), cookie) > 0)
{
throw new ArgumentOutOfRangeException("searchPosition", String.Format("{0} out of range {1}", searchPosition, GetCounterTotal()));
}
if (this.Root == null)
{
return(null);
}
else
{
// find node
ITreeTableNode currentNode = this.Root;
ITreeTableCounter currentNodePosition = start;
return(GetEntryAtCounterPosition(currentNode, start, searchPosition, cookie, preferLeftMost, out currentNodePosition));
}
}
TreeTableWithCounterEntry GetEntryAtCounterPosition(ITreeTableNode currentNode, ITreeTableCounter start, ITreeTableCounter searchPosition, int cookie, bool preferLeftMost, out ITreeTableCounter currentNodePosition)
{
TreeTableWithCounterBranch savedBranch = null;
ITreeTableCounter savedPosition = null;
currentNodePosition = start;
while (!currentNode.IsEntry())
{
var branch = (TreeTableWithCounterBranch)currentNode;
var leftB = (ITreeTableCounterNode)branch.Left;
ITreeTableCounter rightNodePosition = currentNodePosition.Combine(leftB.GetCounterTotal(), cookie);
if (searchPosition.Compare(rightNodePosition, cookie) < 0)
{
currentNode = branch.Left;
}
else if (preferLeftMost && searchPosition.Compare(currentNodePosition, cookie) == 0)
{
while (!currentNode.IsEntry())
{
branch = (TreeTableWithCounterBranch)currentNode;
currentNode = branch.Left;
}
}
else
{
// When the right node matches the searchPosition, there might be entries
// with the same position in the left branch. For example, there might be
// several subsequent tokens on a line in a text editor. Each token will
// have the same line index. When searching for the first token in a line,
// the method will at that time also check the rightmost nodes in the left
// branch.
//
// When preferLeftMost is False, the last token in the line will be returned.
// When preferLeftMost is True, the first last token in the line will be returned.
//
// Note: This only works for "direct hits", that means when the search position
// matches the right node's position. If you search for the "greatest counter
// smaller or equal than searchPosition", the latest node will be returned no
// matter if there were nodes with the same counter before.
//
// Take the YAmountCounter in a TextEditor for example. If you search
// for a YAmount between lines, the last token of the line will be returned.
// In the TextBuffer class special consideration is taken into account for
// this scenario. A generic solution would be too costly in this method.
if (preferLeftMost && searchPosition.Compare(rightNodePosition, cookie) == 0)
{
ITreeTableCounter currentNode2Position = null;
ITreeTableNode currentNode2 = GetEntryAtCounterPosition(branch.Left, currentNodePosition, searchPosition, cookie, preferLeftMost, out currentNode2Position);
if (rightNodePosition.Compare(currentNode2Position, cookie) == 0)
{
currentNode = currentNode2;
currentNodePosition = currentNode2Position;
}
else
{
currentNodePosition = rightNodePosition;
currentNode = branch.Right;
}
}
else
{
if (savedBranch == null)
{
savedBranch = branch;
savedPosition = currentNodePosition;
}
currentNodePosition = rightNodePosition;
currentNode = branch.Right;
}
}
}
// if (preferLeftMost && savedBranch != null)
// {
// ITreeTableCounter currentNode2Position = null;
// ITreeTableNode currentNode2 = GetEntryAtCounterPosition(savedBranch.Left, savedPosition, searchPosition, cookie, preferLeftMost, out currentNode2Position);
// if (currentNodePosition.Compare(currentNode2Position, cookie) == 0)
// currentNode = currentNode2;
//
// while (!currentNode.IsEntry())
// {
// TreeTableWithCounterBranch branch = (TreeTableWithCounterBranch) currentNode;
// currentNode = branch.Left;
// }
// }
return((TreeTableWithCounterEntry)currentNode);
}