public NodeSearchContext(IGraphNode <T> start,
GraphNodeVisitationControl <T> visitTracker,
NodeSearch <T> predicate)
{
Settings = visitTracker;
StartingPoint = start;
MoveTo(start);
_watch = new DisposableStopwatch();
SearchBehavior = predicate;
}
public IEnumerable <IGraphNode <T> > Search(GraphNodeVisitationControl <T> visitationControl,
NodeSearch <T> predicate)
{
var explorer = visitationControl ?? new GraphNodeVisitationControl <T>();
var previousPredicate = predicate;
predicate = (ctx, wanderPoint) => {
var pos = ctx.Cursor;
var ret = previousPredicate(ctx, wanderPoint);
explorer.MarkVisit(pos, explorer.CreateVisitationMark(pos));
return(ret);
};
var context = new NodeSearchContext <T>(this, explorer, predicate);
try {
while (context.Cursor != null)
{
if (context.RunTime > explorer.Timeout)
{
yield break;
}
if (context.CurrentDepth > explorer.MaxVisitDepth)
{
yield break;
}
// by default wandering around the center point
context.AllowWanderingThisCycle = explorer.AllowWandering;
// check the current node before moving outward
if (predicate(context, context.Cursor))
{
yield return(context.Cursor);
}
if (context.Closed)
{
yield break;
}
// the predicate can opt out of wandering
if (!context.AllowWanderingThisCycle)
{
continue;
}
if (context.CurrentDepth == 0)
{
break;
}
var pos = context.Cursor;
foreach (var n in explorer.GetWanderingApproach(context, pos))
{
if (context.SearchBehavior(context, n))
{
yield return(context.Cursor);
}
if (context.Closed)
{
yield break;
}
if (!context.AllowWanderingThisCycle)
{
break;
}
if (context.CurrentDepth == 0)
{
break;
}
}
}
}
finally {
context.Dispose();
}
}
