/*

* Copyright (c) 2005-2007 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:  Fixed digit string handler class

*

*/

#ifndef VPBKENGUTILS_TFIXEDDIGITSTRING_H

#define VPBKENGUTILS_TFIXEDDIGITSTRING_H

// INCLUDES

#include <e32std.h>

namespace VPbkEngUtils {

// FORWARD DECLARATIONS

// CLASS DECLARATIONS

/**

 * Fixed-length digit string.

 * Phone number matching helper class: encodes decimal digit characters to BCD 

 * (Binary Coded Decimal) format for efficient matching.

 */

class TFixedDigitString

    {

    public:

        /**

         * Default constructor. Resets this digit string to empty.

         */

        TFixedDigitString();

        /**

         * Returns the length of this digit string.

         * @return the number of digits in this digit string,

         */

        TInt Length() const;

        /**

         * Returns true if this digit string is empty.

         */

        TBool IsEmpty() const;

        /**

         * Returns the maximum number of digits this object may contain.

         */

        static TInt MaxLength();

        /**

         * Returns non-modifiable decimal digit at position aIndex.

         *

         * @pre  aIndex >= 0 && aIndex < Length()

         * @post result >= 0 && result <= 9

         */

        TInt operator[](TInt aIndex) const;

        /**

         * Compares the digits in this string to another digit string.

         *

         * @param aOther    the other digit string to compare this string with.

         * @param aNumDigits    the number of digits to compare. Zero means

         *                      all digits are compared.

         * @pre Result is undefined if aNumDigits < 0 || aNumDigits > MaxLength().

         * @return true if aNumDigits digits match

         */

        TBool Compare(const TFixedDigitString& aOther, TInt aNumDigits) const;

        /**

         * Resets this digit string to empty.

         * @post Length() == 0

         */

        void Reset();

        /**

         * Encodes digit characters from text to this digit string.

         *

         * @param aDigitsText   text to encode decimal digit characters from.

         *                      Nondigit characters are skipped. The encoded 

         *                      and skipped characters are removed from the 

         *                      parameter. At maximum MaxLength() digits

         *                      are encoded.

         */

        void EncodeDigits(TPtrC& aDigitsText);

    private:  // Implementation

        enum 

            {

            KBitsPerDigit = 4,

            KMaxDigits = 8*sizeof(TUint) / KBitsPerDigit,

            KMaxBits = KMaxDigits * KBitsPerDigit,

            KNaNBCD = 0xf,

            KNaN = -1

            };

        inline TBool DoCompare(const TFixedDigitString& aOther, TInt aNumDigits) const;

    private:  // Data

        /// Own. Bcd digits to be compared

        TUint iBcdDigits;

    };

// INLINE FUNCTIONS

inline TInt TFixedDigitString::MaxLength()

    {

    return KMaxDigits;

    }

/**

 * Inline implementation of Compare.

 */

inline TBool TFixedDigitString::DoCompare

        (const TFixedDigitString& aOther, TInt aNumDigits) const

    {

    const TUint mask = ~TUint(0) >> ((KBitsPerDigit*(KMaxDigits - aNumDigits)) % (KMaxBits));

    if ((iBcdDigits ^ aOther.iBcdDigits) & mask)

        return EFalse;

    else

        return ETrue;

    }

#ifdef NDEBUG

// Inline version of TFixedDigitString::Compare for non-debug builds

inline TBool TFixedDigitString::Compare

        (const TFixedDigitString& aOther, TInt aNumDigits) const

    {

    return DoCompare(aOther, aNumDigits);

    }

#endif

} // namespace VPbkEngUtils

#endif  // VPBKENGUTILS_TFIXEDDIGITSTRING_H