/*

* 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.Text.RegularExpressions;

using System.IO;

using SymbianUtils.Strings;

using SymbianUtils.Streams;

using SymbianImageLib.Common.Header;

using SymbianImageLib.Common.Image;

using SymbianStructuresLib.Compression.Common;

using SymbianImageLib.ROM.Structures;

namespace SymbianImageLib.ROM.Header

{

    internal class SIHeaderROM : SIHeader

    {

        #region Constructors

        public SIHeaderROM( SIImage aImage, Stream aStream )

            : base( aImage )

        {

            aStream.Seek( 0, SeekOrigin.Begin );

            //

            iHeaderData = new byte[ KMaximumRomHeaderSize ];

            int amountRead = aStream.Read( iHeaderData, 0, KMaximumRomHeaderSize );

            //

            string headerText = StringParsingUtils.BytesToString( iHeaderData, KEpocHeaderLength );

            base.Trace( "[SymbianImageHeaderROM] Ctor() - headerText: {0}, amountRead: {1}", headerText, amountRead );

            //

            if ( IsEpocHeader( headerText ) == false )

            {

                throw new NotSupportedException( string.Format( "ROM Image header is unsupported: {0}", headerText ) );

            }

            //

            ReadHeaderData( iHeaderData );

        }

        #endregion

        #region Constants

        public const int KMaximumRomHeaderSize = 0x400;

        public const int KPageSize = 0x1000;

        #endregion

        #region From SymbianImageHeader

        public override TSymbianCompressionType CompressionType

        {

            get

            {

                TSymbianCompressionType ret = TSymbianCompressionType.ENone;

                //

                if ( iRomHdr.CompressionType == (uint) TSymbianCompressionType.EBytePair )

                {

                    ret = TSymbianCompressionType.EBytePair;

                }

                else if ( iRomHdr.CompressionType == (uint) TSymbianCompressionType.EDeflate )

                {

                    ret = TSymbianCompressionType.EDeflate;

                }

                else

                {

                    // Check for byte pair...

                    if ( iRomHdr.RomPageIndex != 0 )

                    {

                        ret = TSymbianCompressionType.EBytePair;

                    }

                }

                //

                return ret;

            }

        }

        public override uint HeaderSize

        {

            get

            {

                uint ret = 0;

                //

                ret += HeaderSizeLoader;

                ret += iRomHdr.Size;

                //

                return ret;

            }

        }

        #endregion

        #region API

        public static bool IsROM( Stream aStream )

        {

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

            {

                string signature = reader.ReadString( KEpocHeaderLength );

                bool ret = IsEpocHeader( signature );

                return ret;

            }

        }

        #endregion

        #region Properties

        public uint UncompressedRomSize

        {

            get { return iRomHdr.UncompressedSize; }

        }

        public uint HeaderSizeLoader

        {

            get { return iLoaderHdr.Size; }

        }

        public uint RomBaseAddress

        {

            get { return iRomHdr.RomBaseAddress; }

        }

        public int NumberOfPages

        {

            get

            {

                int pageAreaStart = iRomHdr.PageableRomStart;

                int pageRomSize = iRomHdr.PageableRomSize;

                int numPages = ( pageAreaStart + pageRomSize + KPageSize - 1 ) / KPageSize;

                //

                return numPages;

            }

        }

        public uint RomPageIndexOffset

        {

            get

            {

                uint ret = iLoaderHdr.Size;

                ret += iRomHdr.RomPageIndex;

                return ret;

            }

        }

        #endregion

        #region Internal constants

        // The signature for Core ROM images used to be EPOCARM4ROM, but now EPOCARM5ROM has

        // also been observed.

        private const int KEpocHeaderLength = 11;

        private static readonly Regex KEpocHeaderTextRegEx = new Regex(

              "EPOCARM\\dROM",

            RegexOptions.Singleline

            | RegexOptions.CultureInvariant

            | RegexOptions.IgnorePatternWhitespace

            | RegexOptions.Compiled

            );

        #endregion

        #region Internal methods

        private static bool IsEpocHeader( string aText )

        {

            Match m = KEpocHeaderTextRegEx.Match( aText );

            bool ret = m.Success;

            return ret;

        }

        private void ReadHeaderData( byte[] aBuffer )

        {

            using ( MemoryStream stream = new MemoryStream( aBuffer ) )

            {

                using ( BinaryReader reader = new BinaryReader( stream ) )

                {

                    iLoaderHdr.Read( reader );

                    iRomHdr.Read( reader );

                }

            }

        }

        #endregion

        #region Data members

        private TRomLoaderHeader iLoaderHdr = new TRomLoaderHeader();

        private TRomHeader iRomHdr = new TRomHeader();

        private readonly byte[] iHeaderData;

        #endregion

    }

}