public bool MoveNext()
{
if (_version != _graph._version)
{
throw new VersionChangedException();
}
if (_done)
{
return(false);
}
if (!_started)
{
_started = true;
foreach (T vertex in _graph.Keys)
{
_queue.Enqueue(vertex);
}
}
// visit the next queued edge
if (_edges.Count > 0)
{
_current = _edges.Dequeue();
return(true);
}
// no more vertices to explore
if (_queue.Count == 0)
{
_done = true;
return(false);
}
// Queue the next edges
while (_queue.Count > 0)
{
T from = _queue.Dequeue();
KeyedCollection <T, GraphEdge <T, TWeight> > edges = _graph[from];
if (edges == null || edges.Count == 0)
{
continue;
}
foreach (GraphEdge <T, TWeight> edge in edges)
{
_edges.Enqueue(new EdgeEntry <T, GraphEdge <T, TWeight> >(from, edge));
}
_current = _edges.Dequeue();
if (_edges.Count > 0)
{
break;
}
}
return(true);
}
void IEnumerator.Reset()
{
if (_version != _graph._version)
{
throw new VersionChangedException();
}
_current = default(EdgeEntry <T, GraphEdge <T, TWeight> >);
_started = false;
_queue.Clear();
_edges.Clear();
_done = _graph.Count == 0;
}
internal EdgeEnumerator([NotNull] WeightedGraphList <T, TWeight> graph)
{
_graph = graph;
_version = graph._version;
_current = default(EdgeEntry <T, GraphEdge <T, TWeight> >);
_started = false;
_done = _graph.Count == 0;
if (_done)
{
_queue = null;
_edges = null;
}
else
{
_queue = new Queue <T>();
_edges = new Queue <EdgeEntry <T, GraphEdge <T, TWeight> > >();
}
}
