/// <summary>
/// Checks if 'node' can be added to 'path' without causing a loop.
/// If yes, adds node to path and returns true. If not, returns false.
/// </summary>
/// <param name="contigPath">List of graph nodes corresponding to contig path.</param>
/// <param name="contigSequence">Sequence of contig being assembled.</param>
/// <param name="nextNode">Next node on the path to be added.</param>
/// <param name="isForwardDirection">Boolean indicating direction.</param>
/// <param name="isSameOrientation">Boolean indicating orientation.</param>
/// <param name="createContigSequences">Boolean indicating whether contig sequences are to be created or not.</param>
/// <returns>Boolean indicating if path was updated successfully.</returns>
private bool CheckAndAddNode(
List <DeBruijnNode> contigPath,
List <byte> contigSequence,
DeBruijnNode nextNode,
bool isForwardDirection,
bool isSameOrientation,
bool createContigSequences)
{
// Since ambiguous extensions have been removed, the only way a link could be in the list
// is if the first item in the list points to this item
if (contigPath.Count > 0 && contigPath.Contains(nextNode)) //contigPath[0]==nextNode)
{
// there is a loop in this link
// Return false indicating no update has been made
return(false);
}
// Add node to contig list
contigPath.Add(nextNode);
if (createContigSequences)
{
// Update contig sequence with sequence from next node
byte symbol = _graph.GetNextSymbolFrom(nextNode, isForwardDirection, isSameOrientation);
if (isForwardDirection)
{
contigSequence.Add(symbol);
}
else
{
contigSequence.Insert(0, symbol);
}
}
return(true);
}
