/*

* Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies). 

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

* 

* Description:

*

*/

using System;

using System.IO;

using System.Text;

using System.Threading;

using System.Collections;

namespace SymbianUtils

{

	public abstract class AsyncBinaryFileReader : AsyncBinaryReaderBase

	{

		#region Construct & destruct

		public AsyncBinaryFileReader( string aFileName )

			: this( aFileName, KDefaultReadChunkSize )

		{

		}

		public AsyncBinaryFileReader( string aFileName, int aReadChunkSize )

		{

			iSourceFileName = aFileName;

			iReadChunkSize = aReadChunkSize;

		}

		#endregion

		#region Constants

		public const int KDefaultReadChunkSize = 512;

		#endregion

		#region Properties

		public string FileName

		{

			get

			{

				string fileName = string.Empty;

				//

				lock( this )

				{

					fileName = iSourceFileName;

				}

				//

				return fileName; 

			}

		}

		protected BinaryReader Reader

		{

			get { return iReader; }

		}

		#endregion

		#region New API

		protected virtual void HandleReaderOpen()

		{

		}

		#endregion

		#region From DisposableObject - Cleanup Framework

		protected override void CleanupManagedResources()

		{

			try

			{

				Cleanup();

			}

			finally

			{

				base.CleanupManagedResources();

			}

		}

		#endregion

		#region From AsyncReaderBase

		protected override void HandleReadStarted()

		{

			iReader = new BinaryReader( new FileStream( FileName, FileMode.Open, FileAccess.Read ) );

			HandleReaderOpen();

			//

			base.HandleReadStarted();

		}

		protected override void HandleReadCompleted()

		{

			try

			{

				Cleanup();

			}

			finally

			{

				base.HandleReadCompleted();

			}

		}

		#endregion

		#region Abstract reading framework

		protected override byte[] ProvideReadBytes()

		{

			byte[] ret = iReader.ReadBytes( iReadChunkSize );

			return ret;

		}

		protected override long Size

		{

			get

			{

				long size = 0;

				//

				lock( this )

				{

					if	( iReader != null && iReader.BaseStream != null )

					{

						size = iReader.BaseStream.Length;

					}

				}

				//

				return size;

			}

		}

		protected override long Position

		{

			get

			{

				long position = 0;

				//

				lock( this )

				{

					if	( iReader != null && iReader.BaseStream != null )

					{

						position = iReader.BaseStream.Position;

					}

				}

				//

				return position;

			}

		}

		#endregion

		#region Internal methods

		private void Cleanup()

		{

			lock( this )

			{

				if	( iReader != null )

				{

					iReader.Close();

					iReader = null;

				}

			}

		}

		#endregion

		#region Data members

		private BinaryReader iReader;

		private readonly int iReadChunkSize;

		private readonly string iSourceFileName;

		#endregion

	}

}