context: // ValueArray.cs - ValueArray wrapper implementation
  //
  // Authors: Mike Kestner <mkestner@ximian.com>
  //
  // Copyright (c) 2003 Novell, Inc.
  //
  // This program is free software; you can redistribute it and/or
  // modify it under the terms of version 2 of the Lesser GNU General 
  // Public License as published by the Free Software Foundation.
  //
  // This program is distributed in the hope that it will be useful,
  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  // Lesser General Public License for more details.
  //
  // You should have received a copy of the GNU Lesser General Public
  // License along with this program; if not, write to the
  // Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  // Boston, MA 02111-1307, USA.
  
  
  namespace GLib {
  
  	using System;
  	using System.Collections;
  	using System.Collections.Generic;
  	using System.Runtime.InteropServices;
  
  	public class ValueArray : IDisposable, ICollection, ICloneable, IWrapper {
  
  		private IntPtr handle = IntPtr.Zero;
  
  		static private IList<IntPtr> PendingFrees = new List<IntPtr> ();
  		static private bool idle_queued = false;
  
  		[DllImport (Global.GObjectNativeDll, CallingConvention = CallingConvention.Cdecl)]
  		static extern IntPtr g_value_array_new (uint n_preallocs);
  
  		public ValueArray (uint n_preallocs)
  		{
  			handle = g_value_array_new (n_preallocs);
  		}
  
  		public ValueArray (IntPtr raw)
  		{
  			handle = raw;
  		}
  		
  		~ValueArray ()
  		{
  			Dispose (false);
  		}
  		
  		// IDisposable
  		public void Dispose ()
  		{
  			Dispose (true);
  			GC.SuppressFinalize (this);
  		}
  
  		[DllImport (Global.GObjectNativeDll, CallingConvention = CallingConvention.Cdecl)]
  		static extern void g_value_array_free (IntPtr raw);
  
  		void Dispose (bool disposing)
  		{
  			if (Handle == IntPtr.Zero)
  				return;
  
  			lock (PendingFrees) {
  				PendingFrees.Add (handle);
  
  				if (! idle_queued) {
  					Timeout.Add (50, new TimeoutHandler (PerformFrees));
  					idle_queued = true;
  				}
  			}
  
  			handle = IntPtr.Zero;
  		}
  
  		static bool PerformFrees ()
  		{
  			IntPtr[] handles;
  
  			lock (PendingFrees) {
  				idle_queued = false;
  
  				handles = new IntPtr [PendingFrees.Count];
  				PendingFrees.CopyTo (handles, 0);
  				PendingFrees.Clear ();
  			}
  
  			foreach (IntPtr h in handles)
  				g_value_array_free (h);
  
  			return false;
  		}
  		
  		public IntPtr Handle {
  			get {
  				return handle;
  			}
  		}
  
  		struct NativeStruct {
  			public uint n_values;
  			public IntPtr values;
  			public uint n_prealloced;
  		}
  
  		NativeStruct Native {
  			get { return (NativeStruct) Marshal.PtrToStructure (Handle, typeof(NativeStruct)); }
  		}
  
  		public IntPtr ArrayPtr {
  			get { return Native.values; }
  		}
  
  		[DllImport (Global.GObjectNativeDll, CallingConvention = CallingConvention.Cdecl)]
  		static extern void g_value_array_append (IntPtr raw, ref GLib.Value val);
  
  		public void Append (GLib.Value val)
  		{
  			g_value_array_append (Handle, ref val);
  		}
  
  		[DllImport (Global.GObjectNativeDll, CallingConvention = CallingConvention.Cdecl)]
  		static extern void g_value_array_insert (IntPtr raw, uint idx, ref GLib.Value val);
  
  		public void Insert (uint idx, GLib.Value val)
  		{
  			g_value_array_insert (Handle, idx, ref val);
  		}
  
  		[DllImport (Global.GObjectNativeDll, CallingConvention = CallingConvention.Cdecl)]
  		static extern void g_value_array_prepend (IntPtr raw, ref GLib.Value val);
  
  		public void Prepend (GLib.Value val)
  		{
  			g_value_array_prepend (Handle, ref val);
  		}
  
  		[DllImport (Global.GObjectNativeDll, CallingConvention = CallingConvention.Cdecl)]
  		static extern void g_value_array_remove (IntPtr raw, uint idx);
  
  		public void Remove (uint idx)
  		{
  			g_value_array_remove (Handle, idx);
  		}
  
  		// ICollection
  		public int Count {
  			get { return (int) Native.n_values; }
  		}
  
  		[DllImport (Global.GObjectNativeDll, CallingConvention = CallingConvention.Cdecl)]
  		static extern IntPtr g_value_array_get_nth (IntPtr raw, uint idx);
  
  		public object this [int index] { 
  			get { 
  				IntPtr raw_val = g_value_array_get_nth (Handle, (uint) index);
  				return Marshal.PtrToStructure (raw_val, typeof (GLib.Value));
  			}
  		}
  
  		// Synchronization could be tricky here. Hmm.
  		public bool IsSynchronized {
  			get { return false; }
  		}
  
  		public object SyncRoot {
  			get { return null; }
  		}
  
  		public void CopyTo (Array array, int index)
  		{
  			if (array == null)
  				throw new ArgumentNullException ("Array can't be null.");
  
  			if (index < 0)
  				throw new ArgumentOutOfRangeException ("Index must be greater than 0.");
  
  			if (index + Count < array.Length)
  				throw new ArgumentException ("Array not large enough to copy into starting at index.");
  			
  			for (int i = 0; i < Count; i++)
  				((IList) array) [index + i] = this [i];
  		}
  
  		private class ListEnumerator : IEnumerator
  		{
  			private int current = -1;
  			private ValueArray vals;
  
  			public ListEnumerator (ValueArray vals)
  			{
  				this.vals = vals;
  			}
  
  			public object Current {
  				get {
  					if (current == -1)
  						return null;
  					return vals [current];
  				}
  			}
  
  			public bool MoveNext ()
  			{
  
gt: 				if (++current >= vals.Count) {