/// <summary>
/// Checks if 'node' can be added to 'link' without
/// violating any conditions pertaining to dangling links.
/// Returns null if loop is found or length exceeds threshold.
/// Otherwise, adds node to link and returns.
/// </summary>
/// <param name="link">Dangling link.</param>
/// <param name="node">Node to be added.</param>
/// <param name="reachedErrorEndPoint">Indicates if we have reached end of dangling link.</param>
/// <returns>Updated dangling link.</returns>
private DeBruijnPath CheckAndAddDanglingNode(DeBruijnPath link, DeBruijnNode node, out bool reachedErrorEndPoint)
{
if (this.erodeThreshold != -1 &&
link.PathNodes.Count == 0 &&
node.KmerCount < this.erodeThreshold)
{
if (node.IsMarkedForDelete)
{
// There is a loop in this link. No need to update link.
// Set flag for end point reached as true and return.
reachedErrorEndPoint = true;
return(link);
}
else
{
node.MarkNodeForDelete();
reachedErrorEndPoint = false;
return(link);
}
}
if (link.PathNodes.Contains(node))
{
// There is a loop in this link. No need to update link.
// Set flag for end point reached as true and return.
reachedErrorEndPoint = true;
return(link);
}
if (link.PathNodes.Count >= this.LengthThreshold)
{
// Length crosses threshold. Not a dangling link.
// So set reached error end point as true and return null.
reachedErrorEndPoint = true;
return(null);
}
// No error conditions found. Add node to link.
reachedErrorEndPoint = false;
link.PathNodes.Add(node);
return(link);
}