[DllImport ("libgstreamer-0.10.dll") ]
static extern int gst_iterator_next (IntPtr iterator, out IntPtr elem);
[DllImport ("libgstreamer-0.10.dll") ]
static extern void gst_iterator_resync (IntPtr iterator);

private class Enumerator : IEnumerator {
	Iterator iterator;
	Hashtable seen = new Hashtable ();

	private object current = null;
	public object Current {
		get {
			return current;
		}
	}

	public bool MoveNext () {
		IntPtr raw_ret;
		bool retry = false;

		if (iterator.Handle == IntPtr.Zero)
			return false;

		do {
			int ret = gst_iterator_next (iterator.Handle, out raw_ret);
			switch (ret) {
				case 0:
					return false;
				case 1:
					if (seen.Contains (raw_ret)) {
						retry = true;
						break;
					}
					seen.Add (raw_ret, null);
					current = Gst.GLib.Object.GetObject (raw_ret, true);
					return true;
				case 2:
					gst_iterator_resync (iterator.Handle);
					retry = true;
					break;
				default:
				case 3:
					throw new Exception ("Error while iterating pads");
			}
		} while (retry);

		return false;
	}

	public void Reset () {
		seen.Clear ();
		if (iterator.Handle != IntPtr.Zero)
			gst_iterator_resync (iterator.Handle);
	}

	public Enumerator (Iterator iterator) {
		this.iterator = iterator;
	}
}

private Enumerator enumerator = null;

public IEnumerator GetEnumerator () {
	if (this.enumerator == null)
		this.enumerator = new Enumerator (this);
	return this.enumerator;
}

[DllImport ("libgstreamer-0.10.dll") ]
static extern void gst_iterator_free (IntPtr iterator);

~Iterator () {
	if (Raw != IntPtr.Zero)
		gst_iterator_free (Raw);
}