// Copyright (c) 1998-2009 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:
// f32\sfat\inc\sl_scandrv.h
// 
//

/**
 @file
 @internalTechnology
*/

#ifndef SL_SCANDRV_H
#define SL_SCANDRV_H

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

const TInt KMaxMatchingEntries		= 2;        ///< Maximum number of matching directory entries scan drive can fix. Any more indicates a fault in the file system
const TInt KMaxArrayDepth			= 6;        ///< Maximum array depth for cluster storage when KMaxScanDepth is reached

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

/**
Data structure used to store the location of a partial VFat entry
*/
struct TPartVFatEntry
	{
	TEntryPos    iEntryPos; ///< The position of the partial VFat entry
	TFatDirEntry iEntry;    ///< The Dos entry The VFat entries belong with
	};

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

/**
Data structure used to store the locations of entries with matching
start cluster numbers. 
*/
struct TMatchingStartCluster
	{
	TEntryPos   iEntries[KMaxMatchingEntries]; ///< The positions of the matching entries
	TInt        iCount;         ///< Count of matching entries
	TInt        iStartCluster;  ///< The matching cluster number found in more than one entry
	};


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

class CCheckFatTable : public CBase
	{
public:
	static CCheckFatTable* NewL(CFatMountCB* aOwner);
	CCheckFatTable(CFatMountCB* aOwner);
	~CCheckFatTable();
	void InitializeL();
	TBool FlushL();
	TBool GetNextClusterL(TInt& aCluster) const;
	void WriteFatEntryEofFL(TInt aCluster);
	TInt ReadL(TInt aFatIndex) const;
	void WriteL(TInt aFatIndex,TInt aValue);
private:
	void WriteMediaDescriptor();
	TInt PosInBytes(TInt aFatIndex) const;
	TInt PosInIndex(TInt aBytePos) const;
	inline TBool IsEof16Bit(TInt aCluster) const;
	inline TBool IsEof12Bit(TInt aCluster) const;
    inline TInt MaxFatIndex() const;
protected:
    TInt iMaxFatIndex;
	TUint8* iCheckFat;
	CFatMountCB* iOwner;
	};


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

/**
Scan drive class performs scan drive functionality on all types
of fat volume.
*/
class CScanDrive : public CBase
	{
public:
	enum TDirError{EScanMatchingEntry=1,EScanPartEntry};
public:
	CScanDrive();
	~CScanDrive();
	static CScanDrive* NewL(CFatMountCB* aMount);
	void ConstructL(CFatMountCB* aMount);
	TInt StartL();
    TBool ProblemsDiscovered() const;  


private:

#if defined(DEBUG_SCANDRIVE)
	void PrintErrors();
	void CompareFatsL() const;
#endif

	void FixupDirErrorL();
	void FindSameStartClusterL();
	TInt FindStartClusterL(TInt aDirCluster);
	void CheckDirStructureL();
	void CheckDirL(TInt aCluster);
	void ProcessEntryL(const TFatDirEntry& aEntry);
	TInt CheckEntryClusterL(const TFatDirEntry& aEntry, const TEntryPos& aEntryPos);
	void WriteClusterChainL(TInt aCluster,TInt aSizeInBytes);
	TBool MoveToVFatEndL(TEntryPos& aPos,TFatDirEntry& aEntry,TInt& aDirLength);
	TBool IsValidVFatEntry(const TFatDirEntry& aEntry,TInt prevNum)const;
	TBool IsDosEntry(const TFatDirEntry& aEntry)const;
	void AddPartialVFatL(const TEntryPos& aStartPos, const TFatDirEntry& aEntry);
	TBool AddMatchingEntryL(const TEntryPos& aEntryPos);
	TInt GetReservedidL(const TEntryPos aVFatPos);
	void WriteNewFatsL();
	void FixPartEntryL();
	void FixMatchingEntryL();
	void MovePastEntriesL(TEntryPos& aEntryPos,TFatDirEntry& aEntry,TInt aToMove,TInt& aDirEntries);
	void AddToClusterListL(TInt aCluster);
	inline TBool AlreadyExistsL(TInt aCluster)const;
	inline TBool IsEndOfRootDir(const TEntryPos& aPos)const;
	inline TBool IsEofF(TInt aVal)const;
	inline TBool IsDirError()const;
    void IndicateErrorsFound();

private:
	CFatMountCB*        iMount;
	CCheckFatTable*     iNewFat;
	TPartVFatEntry      iPartEntry;
	TMatchingStartCluster iMatching;
	TDirError           iDirError;
	TInt                iDirsChecked;
	TInt                iRecursiveDepth;
	RArray<TInt>*       iClusterListArray[KMaxArrayDepth];
	TInt                iListArrayIndex;
    TBool               iFoundProblems; ///< if ETrue after finish, it means that there where some problems FS structure and they were probably fixed;
	};





#endif //SL_SCANDRV_H