// Copyright (c) 1995-2009 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:

//

//  Collection of common constants, utility functions, etc. for the file server and file systems.

//  Definitions here must be filesystem-agnostic, i.e. generic enougs to be used by every file system

//

//  This is the internal file and must not be exported.

/**

    @file

    @internalTechnology

*/

#if !defined(__FILESYSTEM_UTILS_BIT_VECTOR__)

#define __FILESYSTEM_UTILS_BIT_VECTOR__

#if !defined(__FILESYSTEM_UTILS_H__)

#include "filesystem_utils.h"

#endif

//#######################################################################################################################################

/**

    This class represents a bit vector i.e. an array of bits. Vector size can be from 1 to 2^32 bits.

    This class can be created on a stack (but needs to be placed into cleanup stack) or in a heap with the help of its factory methods Create/CreateL

*/

class RBitVector

    {

 public:

    RBitVector(); //-- Creates an empty vector. see Create() methods for memory allocation

   ~RBitVector(); 

    void Close(); 

    TInt Create(TUint32 aNumBits);

    void CreateL(TUint32 aNumBits);

    inline TUint32 Size() const;

    //-- single bit manipulation methods

    inline TBool operator[](TUint32 aIndex) const;

    inline void SetBit(TUint32 aIndex);

    inline void ResetBit(TUint32 aIndex);

    inline void InvertBit(TUint32 aIndex);

    inline void SetBitVal(TUint32 aIndex, TBool aVal);

    void Fill(TBool aVal);

    void Fill(TUint32 aIndexFrom, TUint32 aIndexTo, TBool aVal);

    void Invert();

    TBool operator==(const RBitVector& aRhs) const; 

    TBool operator!=(const RBitVector& aRhs) const;

    //-- logical operations between 2 vectors. 

    void And(const RBitVector& aRhs);

    void Or (const RBitVector& aRhs);

    void Xor(const RBitVector& aRhs);

    TBool Diff(const RBitVector& aRhs, TUint32& aDiffIndex) const;

    TUint32 Num1Bits() const;

    TUint32 Num1Bits(TUint32 aIndexFrom, TUint32 aIndexTo) const;

    TUint32 Num0Bits() const;

    /** Bit search specifiers */

    enum TFindDirection

        {

        ELeft,      ///< Search from the given position to the left (towards lower index)

        ERight,     ///< Search from the given position to the right (towards higher index)

        ENearestL,  ///< Search in both directions starting from the given position; in the case of the equal distances return the position to the left

        ENearestR   ///< Search in both directions starting from the given position; in the case of the equal distances return the position to the right

        //-- N.B the current position the search starts with isn't included to the search.

        };

    TBool Find(TUint32& aStartPos, TBool aBitVal, TFindDirection aDir) const;

    /** panic codes */

    enum TPanicCode

        {

        EIndexOutOfRange,       ///< index out of range

        EWrondFindDirection,    ///< a value doesn't belong to TFindDirection

        ESizeMismatch,          ///< Size mismatch for binary operators

        ENotInitialised,        ///< No memory allocated for the array

        ENotImplemented,        ///< functionality isn't implemented

        EDataAlignment,         ///< wrong data alignment when importing / exporting raw data

        };

 protected:

    //-- these are outlawed. Can't use them because memory allocator can leave and we don't have conthrol on it  in these methods. 

    RBitVector(const RBitVector& aRhs);            

    RBitVector& operator=(const RBitVector& aRhs); 

    void* operator new(TUint); //-- disable creating objects on heap.

    void* operator new(TUint, void*);

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

    void Panic(TPanicCode aPanicCode) const;

    inline TUint32 WordNum(TUint32 aBitPos)  const;

    inline TUint32 BitInWord(TUint32 aBitPos) const;

 protected:

    //-- special interface to acecess raw internal data. It's protected. Derive appropriate class from this one if you wan to use it

    void  DoImportData(TUint32 aStartBit, TUint32 aNumBits, const TAny* apData);

    void  DoExportData(TUint32 aStartBit, TUint32 aNumBits, TDes8& aData) const;

 private:

    TBool FindToRight(TUint32& aStartPos, TBool aBitVal) const;

    TBool FindToLeft (TUint32& aStartPos, TBool aBitVal) const;

    TBool FindNearest(TUint32& aStartPos, TBool aBitVal, TBool aToLeft) const;

    inline TUint32 MaskLastWord(TUint32 aVal) const; 

    inline TBool ItrLeft(TUint32& aIdx) const;

    inline TBool ItrRight(TUint32& aIdx) const;

 protected:

    TUint32   iNumBits; ///< number of bits in the vector

    TUint32*  ipData;   ///< pointer to the data 

    TUint32   iNumWords;///< number of 32-bit words that store bits

    };

//#######################################################################################################################################

//#   inline functions area

//#######################################################################################################################################

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

//-- class RBitVector

/** @return size of the vector (number of bits) */

inline TUint32 RBitVector::Size() const

    {

    return iNumBits;

    } 

/**

    Get a bit by index

    @param aIndex  index in a bit vector

    @return 0 if the bit at pos aIndex is 0, not zero otherwise

    @panic EIndexOutOfRange if aIndex is out of range

*/

inline TBool RBitVector::operator[](TUint32 aIndex) const

    {

    __ASSERT_ALWAYS(aIndex < iNumBits, Panic(EIndexOutOfRange));

    return (ipData[WordNum(aIndex)] & (1<<BitInWord(aIndex)));

    }

/**

    Set a bit at pos aIndex to '1'

    @param aIndex  index in a bit vector

    @panic EIndexOutOfRange if aIndex is out of range

*/

inline void RBitVector::SetBit(TUint32 aIndex)

    {

    __ASSERT_ALWAYS(aIndex < iNumBits, Panic(EIndexOutOfRange));

    ipData[WordNum(aIndex)] |= (1<<BitInWord(aIndex));

    }

/**

    Set a bit at pos aIndex to '0'

    @param aIndex  index in a bit vector

    @panic EIndexOutOfRange if aIndex is out of range

*/

inline void RBitVector::ResetBit(TUint32 aIndex)

    {

    __ASSERT_ALWAYS(aIndex < iNumBits, Panic(EIndexOutOfRange));

    ipData[WordNum(aIndex)] &= ~(1<<BitInWord(aIndex));

    }

/**

    Invert a bit at pos aIndex

    @param aIndex  index in a bit vector

    @panic EIndexOutOfRange if aIndex is out of range

*/

inline void RBitVector::InvertBit(TUint32 aIndex)

    {

    __ASSERT_ALWAYS(aIndex < iNumBits, Panic(EIndexOutOfRange));

    ipData[WordNum(aIndex)] ^= (1<<BitInWord(aIndex));

    }

/**

    Set bit value at position aIndex

    @param aIndex  index in a bit vector

    @panic EIndexOutOfRange if aIndex is out of range

*/

inline void RBitVector::SetBitVal(TUint32 aIndex, TBool aVal)

    {

    if(aVal) 

        SetBit(aIndex);

    else 

        ResetBit(aIndex);

    }

inline TUint32 RBitVector::MaskLastWord(TUint32 aVal) const

    {

    const TUint32 shift = (32-(iNumBits & 0x1F)) & 0x1F;

    return (aVal << shift) >> shift; //-- mask unused high bits

    }

inline TUint32 RBitVector::WordNum(TUint32 aBitPos)  const

    {

    return aBitPos >> 5;

    }

inline TUint32 RBitVector::BitInWord(TUint32 aBitPos) const 

    {

    return aBitPos & 0x1F;

    }

#endif //__FILESYSTEM_UTILS_BIT_VECTOR__