/*

* Copyright (c) 2004-2008 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.Collections.Generic;

using System.Text;

using System.Threading;

using SymbianStructuresLib.Debug.Symbols;

using SymbianStructuresLib.Debug.Symbols.Interfaces;

using SymbianSymbolLib.SourceManagement.Source;

using SymbianSymbolLib.SourceManagement.Provisioning;

using SymbianUtils;

using SymbianUtils.Tracer;

using SymbianUtils.FileTypes;

using SymbianUtils.Threading;

using SLPluginSymbol.Source;

namespace SLPluginSymbol.Data

{

    internal class SymbolFileData : DisposableObject, IEnumerable<SymbolFileSegment>

    {

        #region Delegates & events

        public delegate void DataPreparedHandler( SymbolFileData aData );

        public event DataPreparedHandler DataPrepared = delegate { };

        #endregion

        #region Constructors

        public SymbolFileData( SymbolSource aSource )

		{

            iSource = aSource;

            iData = File.ReadAllBytes( aSource.URI );

        }

        #endregion

        #region API

        public void Split( int aSegmentCount )

        {

            int chunkSize = (int) iData.Length / aSegmentCount;

            int blockPosStart = 0;

            int length = 0;

            //

            for ( int i = 0; i < aSegmentCount; i++ )

            {

                int pos = 0;

                int blockPosEnd = Math.Min( iData.Length - 1, blockPosStart + chunkSize );

                while ( pos >= 0 )

                {

                    pos = Array.IndexOf( iData, KPattern[ 0 ], blockPosEnd );

                    if ( pos > 0 )

                    {

                        if ( pos + 8 >= iData.Length )

                        {

                            break;

                        }

                        else if ( pos + 8 < iData.Length && iData[ pos + 7 ] == KPattern[ 7 ] )

                        {

                            bool isMatch = CompareByteArrays( KPattern, iData, pos );

                            if ( isMatch )

                            {

                                length = pos - blockPosStart;

                                //System.Diagnostics.Debug.WriteLine( string.Format( "Block {0:d2} @ 0x{1:x8}, length: {2:d8}", i, blockPosStart, length ) );

                                //

                                iSegments.Add( new SymbolFileSegment( this, blockPosStart, length ) );

                                blockPosStart = pos;

                                break;

                            }

                            else

                            {

                                // Didn't find a match, move forwards

                                blockPosEnd = pos + 1;

                            }

                        }

                        else

                        {

                            // Didn't find a match, move forwards

                            blockPosEnd = pos + 1;

                        }

                    }

                    else

                    {

                        // Searched to end of file and didn't find another block, so just create

                        // a new reader for everything that remains.

                        length = iData.Length - blockPosStart;

                        //System.Diagnostics.Debug.WriteLine( string.Format( "Block {0:d2} @ 0x{1:x8}, length: {2:d8}", i, blockPosStart, length ) );

                        iSegments.Add( new SymbolFileSegment( this, blockPosStart, length ) );

                        //

                        break;

                    }

                }

            }

            iCollectionIdentifier = new MultiThreadedProcessor<SymbolFileSegment>( this );

        }

        public void FindCollections()

        {

            System.Diagnostics.Debug.Assert( iCollectionIdentifier != null );

            iCollectionIdentifier.ProcessItem += new MultiThreadedProcessor<SymbolFileSegment>.ItemProcessor( CollectionIdentifier_ProcessItem );

            iCollectionIdentifier.EventHandler += new MultiThreadedProcessor<SymbolFileSegment>.ProcessorEventHandler( CollectionIdentifier_EventHandler );

            iCollectionIdentifier.Start( TSynchronicity.EAsynchronous );

        }

        #endregion

        #region Properties

        public SymbolSource Source

        {

            get { return iSource; }

        }

        #endregion

        #region Operators

        public static implicit operator byte[]( SymbolFileData aData )

        {

            return aData.iData;

        }

        #endregion

        #region Internal constants

        private static readonly byte[] KPattern = new byte[] { (byte) 'F', (byte) 'r', (byte) 'o', (byte) 'm', (byte) ' ', (byte) ' ', (byte) ' ', (byte) ' ' };

        #endregion

        #region Event handlers

        private void CollectionIdentifier_EventHandler( MultiThreadedProcessor<SymbolFileSegment>.TEvent aEvent )

        {

            switch ( aEvent )

            {

            default:

                break;

            case MultiThreadedProcessor<SymbolFileSegment>.TEvent.EEventStarting:

                break;

            case MultiThreadedProcessor<SymbolFileSegment>.TEvent.EEventCompleted:

                iCollectionIdentifier.ProcessItem -= new MultiThreadedProcessor<SymbolFileSegment>.ItemProcessor( CollectionIdentifier_ProcessItem );

                iCollectionIdentifier.EventHandler -= new MultiThreadedProcessor<SymbolFileSegment>.ProcessorEventHandler( CollectionIdentifier_EventHandler );

                iCollectionIdentifier.Dispose();

                iCollectionIdentifier = null;

                DataPrepared( this );

                break;

            }

        }

        private void CollectionIdentifier_ProcessItem( SymbolFileSegment aItem )

        {

            aItem.PerformInitialCollectionIdentification();

        }

        #endregion

        #region Internal methods

        private static bool CompareByteArrays( byte[] aSearchFor, byte[] aSearchIn, int aStartPos )

        {

            bool areEqual = true;

            //

            for ( int i = 0; i < aSearchFor.Length; i++ )

            {

                byte c = aSearchFor[ i ];

                int bigBufferIndex = aStartPos + i;

                if ( bigBufferIndex > aSearchIn.Length )

                {

                    // We ran out of data

                    areEqual = false;

                    break;

                }

                else

                {

                    byte b = aSearchIn[ bigBufferIndex ];

                    if ( b != c )

                    {

                        areEqual = false;

                        break;

                    }

                }

            }

            //

            return areEqual;

        }

        #endregion

        #region From IEnumerable<SymbolFileSegment>

        public IEnumerator<SymbolFileSegment> GetEnumerator()

        {

            foreach( SymbolFileSegment segment in iSegments )

            {

                yield return segment;

            }

        }

        System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()

        {

            foreach ( SymbolFileSegment segment in iSegments )

            {

                yield return segment;

            }

        }

        #endregion

        #region From DisposableObject

        protected override void CleanupManagedResources()

        {

            try

            {

                base.CleanupManagedResources();

            }

            finally

            {

                foreach ( SymbolFileSegment seg in iSegments )

                {

                    seg.Dispose();

                }

                //

                if ( iCollectionIdentifier != null )

                {

                    iCollectionIdentifier.Dispose();

                    iCollectionIdentifier = null;

                }

                //

                iSegments.Clear();

                iData = null;

            }

        }

        #endregion

        #region Data members

        private readonly SymbolSource iSource;

        private byte[] iData = null;

        private List<SymbolFileSegment> iSegments = new List<SymbolFileSegment>();

        private MultiThreadedProcessor<SymbolFileSegment> iCollectionIdentifier;

        #endregion

    }

}