private Intersection InitialDestination(Intersection source)
{
// naïve solution: pick first destination at random
Intersection east = source.getEast();
Intersection west = source.getWest();
Intersection north = source.getNorth();
Intersection south = source.getSouth();
List <Intersection> options = new List <Intersection>();
if (east != null)
{
options.Add(east);
}
if (west != null)
{
options.Add(west);
}
if (north != null)
{
options.Add(north);
}
if (south != null)
{
options.Add(south);
}
/**
* Choose a "previous source" retroactively from the first available interface.
* This is just to pouplate the previous_queue object in a sane way
*/
Intersection previous = options[0];
if (previous == east)
{
previous_queue = source.EQ;
}
if (previous == west)
{
previous_queue = source.WQ;
}
if (previous == north)
{
previous_queue = source.NQ;
}
if (previous == south)
{
previous_queue = source.SQ;
}
/**
* Pick a first destination from the second available interface (there will always be at least 2)
* E.g. if the destination is on the north interface, join the southern queue
*/
Intersection destination = options[1];
if (destination == east)
{
current_queue = destination.WQ;
from = "west";
to = "east";
}
if (destination == west)
{
current_queue = destination.EQ;
from = "east";
to = "west";
}
if (destination == north)
{
current_queue = destination.SQ;
from = "south";
to = "north";
}
if (destination == south)
{
current_queue = destination.NQ;
from = "north";
to = "south";
}
current_queue.AddLast(this); // join the current queue
poller = source.getPoller(from, to);
return(destination);
}
private Intersection NextDestination(Intersection origin, Intersection excluding)
{
Intersection east = origin.getEast();
Intersection west = origin.getWest();
Intersection north = origin.getNorth();
Intersection south = origin.getSouth();
List <Intersection> options = new List <Intersection>();
if (east != null && east != excluding)
{
options.Add(east);
}
if (west != null && west != excluding)
{
options.Add(west);
}
if (north != null && north != excluding)
{
options.Add(north);
}
if (south != null && south != excluding)
{
options.Add(south);
}
/** Naïve solution: pick the next destination at random */
Intersection next_hop = options[Deterministic.random.Next(options.Count)];
if (next_hop == origin)
{
throw new InvalidOperationException("next_hop can't be same as origin");
}
if (next_hop == origin.getEast())
{
to = "east";
}
else if (next_hop == origin.getWest())
{
to = "west";
}
else if (next_hop == origin.getNorth())
{
to = "north";
}
else if (next_hop == origin.getSouth())
{
to = "south";
}
if (source == origin.getEast())
{
from = "east";
}
else if (source == origin.getWest())
{
from = "west";
}
else if (source == origin.getNorth())
{
from = "north";
}
else if (source == origin.getSouth())
{
from = "south";
}
poller = origin.getPoller(from, to);
return(next_hop);
}