/*

* Copyright (c) 2004-2006 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:  Provides persistent storage for memory blocks

*

*/

#ifndef C_RSFWPERMANENTSTORE_H

#define C_RSFWPERMANENTSTORE_H

// INCLUDES

#include <e32std.h>

#include <f32file.h>

#include <s32file.h>

// CLASS DECLARATION

class TFileHeader

    {

public:

    TUint   iHeaderStart;           // magic number

    TInt    iHeaderSize;            // (max) header size

    TInt    iBlockSize;             // block size

    HBufC8* iHeader;                // header 

public:

    void ExternalizeL(RWriteStream& aStream) const;

    void InternalizeL(RReadStream& aStream);

    };

class TSlot

    {

 public:

    TInt iIndex;        // data index (used as key for RArray)

    TInt iBlockNumber;  // starting block number

    TInt iBlockCount;   // number of blocks

    };

class CRsfwPermanentStore: public CBase

    {

class TFreeBlockList

    {

 public:

    RArray<TInt> iFreeBlockList; // list of continuous free block sequences

    };

    enum TFileStateInPermanentStore

        {

        EFileStateClosed = 0,

        EFileStateReading,

        EFileStateWriting

        };

public:

    static CRsfwPermanentStore* NewL(const TDesC& aPath,

                                 TInt aHeaderSize = 0,

                                 TInt aBlockSize = 0);

    ~CRsfwPermanentStore();

    void ResetL(TBool aWriting);

    TInt Commit();

    TInt Purge();

    void CompactL();

    void SetHeaderL(TDesC8& aHeader);

    const HBufC8* Header();

    void GetNextDataL(TUint8* aData, TInt& aDataLength, TInt& aIndex);

    void PutDataL(const TUint8* aData, TInt aDataLength, TInt& aIndex);

protected:

    void ConstructL(const TDesC& aPath,

                    TInt aHeaderSize,

                    TInt aBlockSize);

private:

    TInt BlockCount(TInt aDataLength);

    TInt StreamPosition(TInt aBlockNumber);

    TSlot* Slot(TInt aIndex);

    void FixSlot(TInt aOldBlockNumber, TInt aNewBlockNumber);

    void SetFileStateL(TInt aFileState);

    void LoadHeaderL();

    void SaveHeaderL();

    void ClearFreeBlockLists();

    void ClearSlotL(TInt aIndex);

    void WriteBlocksL(const TUint8* aData,

                      TInt aDataLength,

                      TInt aBlockNumber);

    void ReserveSlot(TInt aIndex, TInt aBlockNumber, TInt aBlockCount);

    void PutToFreeBlockList(TInt aBlockPos, TInt aBlockCount);

    TInt GetFromFreeBlockList(TInt aBlockCount);

private:

    RFs                    iFs;               // file server session

    RFile                  iFile;             // the file

    RFileReadStream        iFileReadStream;   // iFile mapped to read stream

    RFileWriteStream       iFileWriteStream;  // iFile mapped to write stream

    TBuf<KMaxPath>         iPath;             // path name of the store file

    TInt                   iHeaderSize;       // size of header payload

    TInt                   iFileHeaderSize;   // total size of header

    TInt                   iBlockSize;        // size of elementary block

    TInt                   iFileState;        // file opening state

    RArray<TFreeBlockList> iFreeBlockLists;   // lists of free blocks

    TFileHeader            iFileHeader;       // file information in the header

    RArray<TSlot>          iSlots;            // maps index/block number

    TInt                   iIndex;            // next slot position

    TInt                   iReadBlockNumber;  // next block to read

    TInt                   iWriteBlockNumber; // next block to write

    HBufC8*                iZeroBlock;        // a filler block

    };

#endif // PERMANENTSTORE_H

// End of File