// 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

#include "sl_std.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

	};

/**

Scan drive class performs scan drive functionality on all types

of fat volume.

*/

class CScanDrive : public CBase

	{

public:

	/**

	Error type found by scan drive, only a single error should occur in 

	any scan of the volume

	*/

	enum TDirError{EScanMatchingEntry=1,EScanPartEntry, ETruncation};

public:

	~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 ReadMediaFatL();

    void DoParseFatL();

    void DoParseFat32L();

    void DoParseFat32Buf(const TPtrC8& aBuf, TUint32& aCurrFatEntry);

	TBool AlreadyUsedL(TUint aCluster) const;

	void SetUsedL(TUint aCluster);

	TUint32 ReadFatL(TInt aClusterNum) const;

	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,TUint 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 MoveToNextEntryL(TEntryPos& aPos);

	void ReadDirEntryL(const TEntryPos& aPos,TFatDirEntry& aDirEntry);

    void IndicateErrorsFound();

private:

	CFatMountCB*            iMount;             ///< The owning Fat mount

	TPartVFatEntry          iPartEntry;         ///< Storage for a partial VFat entry set error

	TMatchingStartCluster   iMatching;          ///< Storage for Matching start cluster error

	TDirError               iDirError;          ///< Indicates the error tpye found also used to indicate if an error has occured

	TInt                    iDirsChecked;       ///< Count of the number of directories checked

	TInt                    iRecursiveDepth;    ///< Depth of recursion the scan has reached

	RArray<TInt>*           iClusterListArray[KMaxArrayDepth]; ///< Size in bytes of the bit packed Fat	Cluster list array used when maximum depth has been reached so that directory may be re-visited. Avoid stack overflow

	TInt                    iListArrayIndex;    ///< Current position into cluster list array

	TInt                    iTruncationCluster; ///< Cluster at which cluster chain truncation should take place, used for truncation errors

    TBool                   iFoundProblems; ///< if ETrue after finish, it means that there where some problems FS structure and they were probably fixed;

    RBitVector              iMediaFatBits;  ///< Storage for bit packed Fat read from media 

    RBitVector              iScanFatBits;   ///< Storage for bit packed Fat built up by the scan

	};

#endif //SL_SCANDRV_H