Peer Graph - Peers and Connections

using System;
using System.Runtime.InteropServices;
using System.Collections;

namespace Peer.Graph
{
	public class PeerCollection : IEnumerable	
	{
		private PeerEnumerator Peers;

		internal PeerCollection(IntPtr hGraph, string PeerName)
		{
			Peers = new PeerEnumerator(hGraph, PeerName);
		}

		internal PeerCollection(IntPtr hGraph)
		{
			Peers = new PeerEnumerator(hGraph, string.Empty);
		}

		private class PeerEnumerator : IEnumerator
		{
			private string peerName;
			private IntPtr hGraph;
			private IntPtr hPeerEnum;
			private int index;
			private int count;

			public PeerEnumerator(IntPtr Graph, string PeerName)
			{
				hGraph = Graph;
				peerName = PeerName;
				Reset();
			}

			#region IEnumerator Members

			public void Reset()
			{
				uint hr;
				if (hPeerEnum != IntPtr.Zero)
				{
					hr = PeerGraphNative.PeerGraphEndEnumeration(hPeerEnum);
					if (hr != 0) throw new PeerGraphException(hr);
					hPeerEnum = IntPtr.Zero;
				}

				IntPtr nameptr = IntPtr.Zero;
				if (peerName != string.Empty) nameptr = Marshal.StringToHGlobalUni(peerName);
				hr = PeerGraphNative.PeerGraphEnumNodes(hGraph, nameptr, out hPeerEnum);
				if (hr != 0) throw new PeerGraphException(hr);

				uint count;
				hr = PeerGraphNative.PeerGraphGetItemCount(hPeerEnum, out count);
				if (hr != 0) throw new PeerGraphException(hr);

				this.count = (int)count;
				index = -1;
			}

			public object Current
			{
				get
				{
					uint ulItem = 1;
					IntPtr Peerptr;
					uint hr = PeerGraphNative.PeerGraphGetNextItem(hPeerEnum, ref ulItem, out Peerptr);
					if (hr != 0) throw new PeerGraphException(hr);

					IntPtr itemptr = Marshal.ReadIntPtr(Peerptr);
					PeerNode peer = new PeerNode((PEER_NODE_INFO)Marshal.PtrToStructure(itemptr, typeof(PEER_NODE_INFO)));

					PeerGraphNative.PeerGraphFreeData(Peerptr);
					return peer;
				}
			}

			public bool MoveNext()
			{
				if (index < count) index++;
				return index == count ? false : true;
			}

			#endregion
		}

		public IEnumerator GetEnumerator()
		{
			return Peers;
		}

		IEnumerator IEnumerable.GetEnumerator() 
		{
			return GetEnumerator();
		}
	}


	public class PeerConnectionCollection : IEnumerable	
	{
		private ConnectionEnumerator connections;

		internal PeerConnectionCollection(IntPtr hGraph, PeerConnectionType Type)
		{
			connections = new ConnectionEnumerator(hGraph, Type);
		}

		internal PeerConnectionCollection(IntPtr hGraph)
		{
			connections = new ConnectionEnumerator(hGraph, PeerConnectionType.All);
		}

		private class ConnectionEnumerator : IEnumerator
		{
			private PeerConnectionType type;
			private IntPtr hGraph;
			private IntPtr hPeerEnum;
			private int index;
			private int count;

			public ConnectionEnumerator(IntPtr Graph, PeerConnectionType Type)
			{
				hGraph = Graph;
				type = Type;
				Reset();
			}

			#region IEnumerator Members

			public void Reset()
			{
				uint hr;
				if (hPeerEnum != IntPtr.Zero)
				{
					hr = PeerGraphNative.PeerGraphEndEnumeration(hPeerEnum);
					if (hr != 0) throw new PeerGraphException(hr);
					hPeerEnum = IntPtr.Zero;
				}

				hr = PeerGraphNative.PeerGraphEnumConnections(hGraph, type, out hPeerEnum);
				if (hr != 0) throw new PeerGraphException(hr);

				uint count;
				hr = PeerGraphNative.PeerGraphGetItemCount(hPeerEnum, out count);
				if (hr != 0) throw new PeerGraphException(hr);

				this.count = (int)count;
				index = -1;
			}

			public object Current
			{
				get
				{
					uint ulItem = 1;
					IntPtr connectionptr;
					uint hr = PeerGraphNative.PeerGraphGetNextItem(hPeerEnum, ref ulItem, out connectionptr);
					if (hr != 0) throw new PeerGraphException(hr);

					IntPtr itemptr = Marshal.ReadIntPtr(connectionptr);
					PeerConnection connection = new PeerConnection((PEER_CONNECTION_INFO)Marshal.PtrToStructure(itemptr, typeof(PEER_CONNECTION_INFO)));

					PeerGraphNative.PeerGraphFreeData(connectionptr);
					return connection;
				}
			}

			public bool MoveNext()
			{
				if (index < count) index++;
				return index == count ? false : true;
			}

			#endregion
		}

		public IEnumerator GetEnumerator()
		{
			return connections;
		}

		IEnumerator IEnumerable.GetEnumerator() 
		{
			return GetEnumerator();
		}
	}
}