// Copyright (c) 1996-2009 Nokia Corporation and/or its subsidiary(-ies).

// All rights reserved.

// This component and the accompanying materials are made available

// under the terms of the License "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:

// 

//

#include "sl_std.h"

#include "sl_cache.h"

#include <e32math.h>

const TInt KSeekIndexSize=128; // Cache 128 clusters

const TInt KSeekIndexSizeLog2=7;

const TInt KFirstClusterNum=2;

CFatFileCB::CFatFileCB()

	{

	__PRINT1(_L("CFatFileCB created 0x%x"),this);

	}

CFatFileCB::~CFatFileCB()

	{

	__PRINT1(_L("~CFatFileCB deleted 0x%x"),this);

    //-- a nasty trick to find out if the CFatFileCB is in consistent state on the moment of destruction.

    //-- Because of OOM conditions CFatFileCB might not be fully constructed and to be deleted, while FlushAll()

    //-- implies valid iMount.

    const CMountCB* pMount  = &Mount();

    if(pMount)

        {//-- do some finalisation work if CMountCB is valid

        if(FileAttModified())

            {

            IndicateFileTimeModified(ETrue); //-- this will force writing file modification time to the media on Flush

            TRAP_IGNORE(FlushAllL());

        }

        }

    delete[] iSeekIndex;

	}

void CFatFileCB::CreateSeekIndex()

//

// Create a seek index

//

	{

	iSeekIndex = new TUint32[KSeekIndexSize];

	if (iSeekIndex == NULL)

		return;

	Mem::FillZ(iSeekIndex, sizeof(TUint32) * KSeekIndexSize);

	iSeekIndexSize=CalcSeekIndexSize(FCB_FileSize());

	}

TInt CFatFileCB::SeekToPosition(TUint aNewRelCluster, TUint aClusterOffset)

//

// Use the seek index to set iCurrentPos.iCluster as close as possible to aNewRelCluster

// Return aNewRelCluster-aCurrentPos.iCluster

//

	{

	TInt clusterOffset=aClusterOffset;

	TInt seekPos=(aNewRelCluster>>iSeekIndexSize)-1;

	__ASSERT_DEBUG(seekPos<KSeekIndexSize,Fault(EFatFileSeekIndexTooSmall));

	while(seekPos>=0 && iSeekIndex[seekPos]==0 && clusterOffset!=0)

		{

		seekPos--;

		clusterOffset--;

		}

	if (clusterOffset==0) // Counted back to the current cluster

		return(aClusterOffset);

	if (seekPos<0)

		{

		iCurrentPos.iCluster=FCB_StartCluster();

		return(aNewRelCluster);

		}

	iCurrentPos.iCluster=iSeekIndex[seekPos];

	return(aNewRelCluster-((seekPos+1)<<iSeekIndexSize));

	}

void CFatFileCB::SetSeekIndexValueL(TUint aRelCluster, TUint aStoredCluster)

//

// Sets a value in the seekindex

//

	{

	TInt seekPos=(aRelCluster>>iSeekIndexSize)-1;

	__ASSERT_DEBUG(seekPos<KSeekIndexSize,Fault(EFatFileSeekIndexTooSmall));

	__ASSERT_DEBUG(seekPos>=0,Fault(EFatFileSeekIndexTooSmall2));

	iSeekIndex[seekPos] = aStoredCluster;

	}

TBool CFatFileCB::IsSeekBackwards(TUint aPos)

//

// Return true if aPos<currentPos

//

	{

	TUint cluster=iCurrentPos.iCluster<<ClusterSizeLog2();

	TInt offset=ClusterRelativePos(iCurrentPos.iPos);

	TUint currentPos=cluster+offset;

	return(aPos<currentPos);

	}

void CFatFileCB::CheckPosL(TUint aPos)

//

// Check that the file is positioned correctly.

// If aPos<currentPos attempt to guess the new position.

//

	{

	__PRINT1(_L("CFatFileCB::CheckPosL(%d)"), aPos);

	if (aPos==iCurrentPos.iPos)

		return;

    __ASSERT_DEBUG(aPos <= FCB_FileSize(), Fault(EFatFilePosBeyondEnd));

	if (FileSizeModified() && IsSeekBackwards(aPos))

		FlushDataL(); 

	TUint newRelCluster=aPos>>ClusterSizeLog2();

	if ( aPos && (aPos==(newRelCluster<<ClusterSizeLog2())) )

		newRelCluster--;

	TUint oldRelCluster=iCurrentPos.iPos>>ClusterSizeLog2();

	if ( iCurrentPos.iPos && (iCurrentPos.iPos==(oldRelCluster<<ClusterSizeLog2())) )

		oldRelCluster--;	

	TInt clusterOffset=newRelCluster-oldRelCluster;

	TUint32 oldCluster=iCurrentPos.iCluster;

	iCurrentPos.iPos=aPos;

	if (clusterOffset==0)

		return;

	TInt seekOffset=clusterOffset;

	if (iSeekIndex!=NULL)

		{ // Can alter iCurrentPos.iCluster

		seekOffset=SeekToPosition(newRelCluster,seekOffset);

		if (seekOffset==0)

			return;

		}

	if (clusterOffset==-1 && seekOffset!=1)

		{ // Check previous cluster

		TUint32 cluster=oldCluster-1;

		if (FAT().GetNextClusterL(cluster) && cluster==oldCluster)

			{

            iCurrentPos.iCluster=oldCluster-1;

			return;

			}

		}

	if (seekOffset<0)

		{

		seekOffset=newRelCluster;

		iCurrentPos.iCluster=FCB_StartCluster();

		}

	while (seekOffset--)

		{

        if (!FAT().GetNextClusterL(iCurrentPos.iCluster))

            {

            __PRINT(_L("CFatFileCB::CheckPosL() corrupt#1"));

            User::Leave(KErrCorrupt);

            }

        TInt cluster=newRelCluster-seekOffset;

		if (iSeekIndex!=NULL && cluster && (cluster>>iSeekIndexSize)<<iSeekIndexSize==cluster)

			SetSeekIndexValueL(cluster,iCurrentPos.iCluster);

		}

	}

//-----------------------------------------------------------------------------

/** 

    Initialize FileCB from file's entry data.

    @param  aFatDirEntry        this file DOS dir entry.

    @param  aFileDosEntryPos    this file DOS entry dir. iterator in the parent directory.

*/

void CFatFileCB::SetupL(const TFatDirEntry& aFatDirEntry, const TEntryPos& aFileDosEntryPos)

	{

	__PRINT1(_L("CFatFileCB::SetupL[0x%x]"), this);

    //-- set up a file control block

	iCurrentPos.iCluster= FatMount().StartCluster(aFatDirEntry);

	iCurrentPos.iPos=0;

    SetAtt(aFatDirEntry.Attributes());

	SetModified(aFatDirEntry.Time(FatMount().TimeOffset()));

    FCB_SetStartCluster(iCurrentPos.iCluster);

    FCB_SetFileSize(aFatDirEntry.Size()); 

	iFileDosEntryPos = aFileDosEntryPos;

    SetMaxSupportedSize(KMaxSupportedFatFileSize);

    //-- create seek index

    ASSERT(!iSeekIndex);

    CreateSeekIndex();

    if(!iSeekIndex)

        User::Leave(KErrNoMemory);

    IndicateFileAttModified(EFalse);

    IndicateFileSizeModified(EFalse);

    IndicateFileTimeModified(EFalse);

	}

//-----------------------------------------------------------------------------

/**

    Read data from the file.

    @param  aFilePos    start read position within a file

    @param  aLength     how many bytes to read; on return will be how many bytes actually read

    @param  aDes        local buffer desctriptor

    @param  aMessage    from file server, used to write data to the buffer in different address space.

    @param  aDesOffset  offset within data descriptor where the data will be copied

    @leave on media read error

*/

void CFatFileCB::ReadL(TInt64 aPos,TInt& aLength, TDes8* aDes, const RMessagePtr2& aMessage, TInt aOffset)

	{

	__PRINT3(_L("CFatFileCB::ReadL[0x%x] pos=%LU len=%d"), this, aPos, aLength);

    if((TUint64)aPos > KMaxSupportedFatFileSize-1)

        User::Leave(KErrNotSupported);  //-- max. position in the file is 0xFFFFFFFE

    FatMount().CheckStateConsistentL();

	CheckPosL(I64LOW(aPos));

	const TUint startPos = iCurrentPos.iPos;

	const TUint curSize  = FCB_FileSize();

	const TUint length   = (TUint)aLength;

	if((startPos + length > curSize) || (startPos > startPos + length) )

		aLength=curSize-startPos;

    FatMount().ReadFromClusterListL(iCurrentPos,aLength,aDes,aMessage,aOffset);

	aLength=iCurrentPos.iPos-startPos;

	}

void CFatFileCB::ReadL(TInt aFilePos,TInt& aLength,const TAny* aTrg,const RMessagePtr2& aMessage)

	{

	ReadL(TInt64(aFilePos),aLength,(TDes8*) aTrg,aMessage, 0);

	}

//-----------------------------------------------------------------------------

/**

    Write data to the file.

    @param  aFilePos    start write position within a file

    @param  aLength     how many bytes to write; on return contain amount of data actually written

    @param  aDes        local buffer desctriptor

    @param  aMessage    from file server, used to write data to the media from different address space.

    @param  aDesOffset  offset within data descriptor 

    @leave on media read error

*/

void CFatFileCB::WriteL(TInt64 aPos,TInt& aLength,const TDesC8* aSrc,const RMessagePtr2& aMessage, TInt aOffset)

	{

	__PRINT3(_L("CFatFileCB::WriteL[0x%x] pos=%LU len=%d"), this, aPos, aLength);

	// FAT supports 32 bits only for file size

   	TUint64 endPos = aPos + aLength;

   	if(endPos > KMaxSupportedFatFileSize)

   		User::Leave(KErrNotSupported);

    FatMount().CheckStateConsistentL();

    FatMount().CheckWritableL();

    const TUint pos = I64LOW(aPos);

  	CheckPosL(pos);

	const TUint startCluster = FCB_StartCluster();

	const TUint length       = (TUint)aLength;

	endPos = iCurrentPos.iPos + length; 

	if ((endPos           > FCB_FileSize()) ||

	    (iCurrentPos.iPos > endPos)         ) // Overflow condition 

		DoSetSizeL(iCurrentPos.iPos+length,EFalse);

	TUint startPos=iCurrentPos.iPos;

	TUint badcluster=0;

	TUint goodcluster=0;

	TRAPD(ret, FatMount().WriteToClusterListL(iCurrentPos,aLength,aSrc,aMessage,aOffset,badcluster, goodcluster));

	if (ret == KErrCorrupt || ret == KErrDied)

		{

        if(startCluster == 0)

			{ //Empty File, revert all the clusters allocated.

			const TUint32 cluster = FCB_StartCluster();

			FCB_SetStartCluster(0);

			FCB_SetFileSize(0);

			IndicateFileSizeModified(ETrue);

			FlushAllL();

			iCurrentPos.iCluster = 0;

			iCurrentPos.iPos = 0;

			FAT().FreeClusterListL(cluster);

			FAT().FlushL();

			}

		else

			{ //Calculate the clusters required based on file size, revert extra clusters if allocated.

			const TUint curSize = FCB_FileSize();

			TUint ClustersNeeded = curSize >> ClusterSizeLog2();

			if(curSize > (ClustersNeeded << ClusterSizeLog2()))

				{

				ClustersNeeded++;

				}

			TUint32 cluster = FCB_StartCluster();

			while(--ClustersNeeded)

				{

				FAT().GetNextClusterL(cluster);

				}

			iCurrentPos.iCluster = cluster;

			if (FAT().GetNextClusterL(cluster))

				{

				FAT().FreeClusterListL(cluster);

				}

			FAT().WriteFatEntryEofL(iCurrentPos.iCluster);

			FAT().FlushL();

			}

		}

	User::LeaveIfError(ret);

	if(badcluster != 0)

		{

		if(FCB_StartCluster() == badcluster)

			{

            FCB_SetStartCluster(goodcluster);

			FlushStartClusterL();

			}

		else

			{

			TUint32 aCluster = FCB_StartCluster();

			do

				{

                if((TUint)badcluster == FAT().ReadL(aCluster))

					{

					FAT().WriteL(aCluster, goodcluster);

					FAT().FlushL();

					break;

					}

				}

			while(FAT().GetNextClusterL(aCluster));

			}

		}

	aLength=iCurrentPos.iPos-startPos;

		{

		WriteFileSizeL(pos+aLength);

		}

	}

void CFatFileCB::WriteL(TInt aFilePos,TInt& aLength,const TAny* aSrc,const RMessagePtr2& aMessage)

	{

	WriteL(TInt64(aFilePos),aLength,(TDesC8*) aSrc,aMessage, 0);

	}

//-----------------------------------------------------------------------------

void CFatFileCB::ResizeIndex(TInt aNewMult,TUint aNewSize)

//

// Resize the seek index to accomodate a larger or smaller filesize

// Assumes KSeekIndexSize is a power of 2.

//

	{

	TInt maxNewIndex=aNewSize>>(ClusterSizeLog2()+aNewMult);

	TInt    index=0;

	TInt	indexEnd=KSeekIndexSize;

	TInt	newValEnd=maxNewIndex;

	if (iSeekIndexSize<aNewMult)

		{

		TInt newVal=index;

		TInt step=1<<(aNewMult-iSeekIndexSize);

		index+=step-1;

		while(index<indexEnd && newVal<newValEnd)

			{

			iSeekIndex[newVal] =  iSeekIndex[index];

			newVal++;

			index+=step;

			}

		while(newVal<indexEnd)

			iSeekIndex[newVal++] =  0;

		}

	else

		{

		TInt diffSize = iSeekIndexSize-aNewMult;

		TInt oldVal=(KSeekIndexSize>>diffSize) - 1;

		TInt newVal=indexEnd-1;

		TInt skip=(1<<diffSize)-1;

		if ((iSeekIndexSize - aNewMult) > KSeekIndexSizeLog2)

			{

            ClearIndex(0); //-- Invalidate every entry.

			}

		else

			{

			while(newVal>=index)

				{

				iSeekIndex[newVal--] =  iSeekIndex[oldVal--];

				for(TInt i=skip;i>0;i--)

					{	

					iSeekIndex[newVal--] = 0;

					}

				}

			}

		}

	iSeekIndexSize=aNewMult;

	}

/**

    Zero freed clusters in the index

    @param  aNewSize new size of the file that the index corresponds to.

            if = 0  all existing index will be zero filled

*/ 

void CFatFileCB::ClearIndex(TUint aNewSize)

	{

	if (!iSeekIndex)

	    return;

    if(aNewSize==0)

    	{

    	//-- zero fill all the array

        Mem::FillZ(iSeekIndex, KSeekIndexSize*sizeof(TUint32));

		return;

    	}

	// Files that fill up a cluster exactly do not have a trailing empty

	// cluster. So the entry for that position must also be invalidated

	aNewSize--;

	TInt firstInvalidIndex=aNewSize>>(iSeekIndexSize+ClusterSizeLog2());

	TInt indexLen=KSeekIndexSize-firstInvalidIndex;

	Mem::FillZ(iSeekIndex+firstInvalidIndex, indexLen * sizeof(TUint32));

	}

TInt CFatFileCB::CalcSeekIndexSize(TUint aSize)

//

// Find the nearest power of 2 > aSize

//

	{

	TInt count = 0;

	const TUint indexSize=KSeekIndexSize<<ClusterSizeLog2();//KSeekIndexSize=128

	if (aSize<=indexSize)

	  return(count);

	while((aSize>>=1)>0)

		{

		count++;

		}

	return (count - (KSeekIndexSizeLog2 + ClusterSizeLog2()) + 1);

	}

//-----------------------------------------------------------------------------

/**

    Set file size.

    @param aSize new file size.

*/

void CFatFileCB::SetSizeL(TInt64 aSize)

	{

	__PRINT2(_L("CFatFileCB::SetSizeL[0x%x] sz=%LU"), this, aSize);

	//-- max. file size for FAT is 4GB-1

	if (I64HIGH(aSize))

		User::Leave(KErrNotSupported);

	}

void CFatFileCB::SetSizeL(TInt aSize)

	{

	SetSizeL(TInt64(aSize));

	}

//-----------------------------------------------------------------------------

/**

    Shrink file to zero size.

*/