Here's a simple generic PriorityQueue<T> class that I created when I needed some of this basic functionality recently.
[code][NO-PARSE]internal enum PriorityLevel
{
Low,
Medium,
High
}
internal class PriorityQueue<T> : ICollection, IReadOnlyCollection<T>
{
private readonly Dictionary<PriorityLevel, Queue<T>> _priorityQueues;
public int Count
{
get
{
return _priorityQueues[PriorityLevel.High].Count
+ _priorityQueues[PriorityLevel.Medium].Count
+ _priorityQueues[PriorityLevel.Low].Count;
}
}
public PriorityQueue()
: this(64)
{ }
public PriorityQueue(int capacity)
{
_priorityQueues = new Dictionary<PriorityLevel, Queue<T>>(3)
{
{ PriorityLevel.Low, new Queue<T>(capacity) },
{ PriorityLevel.Medium, new Queue<T>(capacity) },
{ PriorityLevel.High, new Queue<T>(capacity) }
};
}
public void Clear()
{
_priorityQueues[PriorityLevel.Low].Clear();
_priorityQueues[PriorityLevel.Medium].Clear();
_priorityQueues[PriorityLevel.High].Clear();
}
public void Enqueue(PriorityLevel priority, T item)
{
_priorityQueues[priority].Enqueue(item);
}
public T Dequeue()
{
if (_priorityQueues[PriorityLevel.High].Count != 0)
return _priorityQueues[PriorityLevel.High].Dequeue();
if (_priorityQueues[PriorityLevel.Medium].Count != 0)
return _priorityQueues[PriorityLevel.Medium].Dequeue();
return _priorityQueues[PriorityLevel.Low].Dequeue();
}
public T Peek()
{
if (_priorityQueues[PriorityLevel.High].Count != 0)
return _priorityQueues[PriorityLevel.High].Peek();
if (_priorityQueues[PriorityLevel.Medium].Count != 0)
return _priorityQueues[PriorityLevel.Medium].Peek();
return _priorityQueues[PriorityLevel.Low].Peek();
}
public IEnumerator<T> GetEnumerator()
{
foreach (var item in _priorityQueues[PriorityLevel.High])
yield return item;
foreach (var item in _priorityQueues[PriorityLevel.Medium])
yield return item;
foreach (var item in _priorityQueues[PriorityLevel.Low])
yield return item;
}
IEnumerator IEnumerable.GetEnumerator()
{
return GetEnumerator();
}
public void CopyTo(Array array, int index)
{
using (var enumerator = GetEnumerator())
{
while (enumerator.MoveNext())
{
array.SetValue(enumerator.Current, index++);
}
}
}
int ICollection.Count { get { return Count; } }
public object SyncRoot { get { return this; } }
public bool IsSynchronized { get { return false; } }
int IReadOnlyCollection<T>.Count { get { return Count; } }
}[/NO-PARSE][/code]
Works pretty decent for what it is. :thumbsup2:
