/*

* 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.Collections.Generic;

using System.Text;

using System.IO;

using SymbianUtils.Strings;

using SymbianUtils.Streams;

using SymbianImageLib.Common.Header;

using SymbianImageLib.Common.Image;

using SymbianStructuresLib.Compression.Common;

using SymbianImageLib.ROFS.Structures;

using SymbianImageLib.ROFS.Header.Types;

namespace SymbianImageLib.ROFS.Header

{

    internal abstract class SIHeaderROF : SIHeader

    {

        #region Static constructor

        public static SIHeaderROF New( SIImage aImage, Stream aStream )

        {

            byte[] signature = new byte[ 4 ];

            int readResult = aStream.Read( signature, 0, signature.Length );

            if ( readResult != 4 )

            {

                throw new Exception( "Unable to read ROF signature" );

            }

            // Put us back where we were

            aStream.Seek( -signature.Length, SeekOrigin.Current );

            // Convert signature to string and compare against known types.

            string headerText = StringParsingUtils.BytesToString( signature );

            aImage.Trace( "[SymbianImageHeaderROF] New() - headerText: {0}", headerText );

            //

            SIHeaderROF ret = null;

            switch ( headerText )

            {

            case "ROFX":

                ret = new SIHeaderROFS( aImage, aStream );

                break;

            case "ROFS":

                ret = new SIHeaderROFX( aImage, aStream );

                break;

            default:

                throw new NotSupportedException( "Unsupported ROF type" );

            }

            //

            return ret;

        }

        #endregion

        #region Constructors

        protected SIHeaderROF( SIImage aImage, Stream aStream )

            : base( aImage )

        {

            // Skip over identifier

            aStream.Seek( 4, SeekOrigin.Begin );

            // Read header size and then put us back at the start of the stream

            // ready to read the entire header.

            int headerSize = aStream.ReadByte();

            aStream.Seek( 0, SeekOrigin.Begin );

            //

            iHeaderData = new byte[ headerSize ];

            aStream.Read( iHeaderData, 0, iHeaderData.Length );

            //

            ReadHeaderData( iHeaderData );

        }

        #endregion

        #region API

        public static bool IsROFS( Stream aStream )

        {

            using ( SymbianStreamReaderLE reader = SymbianStreamReaderLE.New( aStream, SymbianStreamReaderLE.TCloseOperation.EResetPosition ) )

            {

                string signature = reader.ReadString( 4 );

                bool ret = ( signature == KImageROFS || signature == KImageROFX );

                return ret;

            }

        }

        #endregion

        #region Constants

        public const string KImageROFS = "ROFS";

        public const string KImageROFX = "ROFX";

        #endregion

        #region From SymbianImageHeader

        public override TSymbianCompressionType CompressionType

        {

            get

            {

                // ROFS image itself is not compressed - however, the individual ROFS entries 

                // themselves are likely compressed.

                return TSymbianCompressionType.ENone;

            }

        }

        public override uint HeaderSize

        {

            get { return iRofsHdr.Size; }

        }

        #endregion

        #region API

        #endregion

        #region Properties

        internal TRofsHeader InternalHeader

        {

            get { return iRofsHdr; }

        }

        #endregion

        #region Internal methods

        private void ReadHeaderData( byte[] aBuffer )

        {

            using ( MemoryStream stream = new MemoryStream( aBuffer ) )

            {

                using ( BinaryReader reader = new BinaryReader( stream ) )

                {

                    iRofsHdr.Read( reader );

                }

            }

        }

        #endregion

        #region Data members

        private TRofsHeader iRofsHdr = new TRofsHeader();

        private readonly byte[] iHeaderData;

        #endregion

    }

}