/// <summary>
/// Find the <see cref="VertexNode"/> for a given edge, if it exists.
/// </summary>
/// <param name="graph">Graph to look in</param>
/// <param name="fromVtx">Start Vertex</param>
/// <param name="ToVtx">End Vertex, or null if we don't care</param>
/// <returns>Pointer to the vertex node, if found</returns>
/// <!-- Based off 3.1.1 -->
public static VertexNode findNodeForEdge(
ref VertexGraph graph,
GeoCoord fromVtx,
GeoCoord toVtx)
{
uint index = _hashVertex(fromVtx, graph.res, graph.numBuckets);
var currentBucket = graph.buckets[(int)index];
var nodeIndex = currentBucket.FindIndex(
t => GeoCoord.geoAlmostEqual(t.from, fromVtx) &&
(toVtx == null || GeoCoord.geoAlmostEqual(t.to, toVtx))
);
return(nodeIndex < 0
? null
: currentBucket[nodeIndex]);
}
/// <summary>Add an edge to the graph</summary>
/// <param name="graph">Graph to add node to</param>
/// <param name="fromVtx">Start vertex</param>
/// <param name="toVtx">End vertex</param>
/// <returns>new node</returns>
/// <!-- Based off 3.1.1 -->
public static VertexNode addVertexNode(ref VertexGraph graph, GeoCoord fromVtx,
GeoCoord toVtx)
{
// Make the new node
VertexNode node = _initVertexNode(fromVtx, toVtx);
// Determine location
var index = _hashVertex(fromVtx, graph.res, graph.numBuckets);
// Check whether there's an existing node in that spot
List <VertexNode> currentNode = graph.buckets[(int)index];
if (currentNode.Count == 0)
{
// Set bucket to the new node
graph.buckets[(int)index].Add(node);
}
else
{
// Go through the list to make sure the
// edge doesn't already exist
//
// NOTE: Later, use a Hashset
foreach (var vertexNode in graph.buckets[(int)index])
{
if (GeoCoord.geoAlmostEqual(vertexNode.from, fromVtx) &&
GeoCoord.geoAlmostEqual(vertexNode.to, toVtx))
{
// already exists, bail.
return(vertexNode);
}
}
// Add the new node to the end of the list
graph.buckets[(int)index].Add(node);
}
graph.size++;
return(node);
}