/*

* Copyright (c) 2000-2004 Nokia Corporation and/or its subsidiary(-ies). 

* All rights reserved.

* This component and the accompanying materials are made available

* 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:      

*

*/

#include <bldvariant.hrh>

#include "PictographObserver.h"

#include <featmgr.h>  

#include <e32std.h>

#include <charconv.h>

#include <convutils.h>

#include <jisx0201.h>

#include <jisx0208.h>

#include <shiftjis.h>

#include <convdata.h>

const TUint KSingleByteRangeFirstBlockStart=0x00;

const TUint KSingleByteRangeFirstBlockEnd=0x7f;

const TUint KSingleByteRangeSecondBlockStart=0xa1;

const TUint KSingleByteRangeSecondBlockEnd=0xdf;

const TUint KFirstByteRangeFirstBlockStart=0x81;

const TUint KFirstByteRangeFirstBlockEnd=0x9f;

const TUint KFirstByteRangeFirstBlockLength=(KFirstByteRangeFirstBlockEnd+1)-KFirstByteRangeFirstBlockStart;

const TUint KFirstByteRangeSecondBlockStart=0xe0;

// Ken Lunde's book "CJKV Information Processing" (page 176) says this

// constant should be 0xef, but no Shift-JIS characters in

// \charconv\data\JISX0208.TXT have a first byte greater than 0xea, and

// some extensions of Shift-JIS may use the 0xeb-0xef range for the first

// byte of their characters (e.g. "MOPERA"), and in order for users of this

// DLL to be able to implement these extensions using the

// aArrayOfAdditionalXxxxx parameters, this constant therefore needs to

// be set as low as possible, i.e. to 0xea

const TUint KFirstByteRangeSecondBlockEnd=0xea;

const TUint KFirstByteRangeOtherBlockEnd = 0xfc;

const TUint KPictoFirstByteStart = 0xF0;

const TUint KPictoFirstByteEnd = 0xF9;

const TUint KSecondByteRangeFirstBlockStart=0x40;

const TUint KSecondByteRangeFirstBlockEnd=0x7e;

const TUint KSecondByteRangeFirstBlockLength=(KSecondByteRangeFirstBlockEnd+1)-KSecondByteRangeFirstBlockStart;

const TUint KSecondByteRangeSecondBlockStart=0x80;

const TUint KSecondByteRangeSecondBlockEnd=0xfc;

// SecureID for Brower app

const TUint32 KBrowserSecureId = 0x10008D39;

// Define for converting from YenSign to BackSlash

const TUint KCharacterCodeForYenSign = 0x00A5;

const TUint KCharacterCodeForBackSlash = 0x005C;

TInt BytesInOtherDoubleByteAreas(const TDesC8& aShiftJis);

TInt OneIfNotValid(const TDesC8& aShiftJis);

TBool IsJisX0208LeadByte(TUint a)

    {

    return (KFirstByteRangeFirstBlockStart <= a

        && a <= KFirstByteRangeFirstBlockEnd)

        || (KFirstByteRangeSecondBlockStart <= a

        && a <= KFirstByteRangeSecondBlockEnd);

    }

TBool IsValidTrailByte(TUint a)

    {

    return KSecondByteRangeFirstBlockStart <= a

        && a <= KSecondByteRangeSecondBlockEnd

        && a != KSecondByteRangeFirstBlockEnd + 1;

    }

TBool IsOtherLeadByte(TUint a)

    {

    if ( FeatureManager::FeatureSupported(KFeatureIdJapanesePicto) )

        {        

        return ((KFirstByteRangeSecondBlockEnd < a && a <= KFirstByteRangeOtherBlockEnd)

                && (a < KPictoFirstByteStart || a > KPictoFirstByteEnd));

        }

    else

        {        

        return KFirstByteRangeSecondBlockEnd < a

                && a <= KFirstByteRangeOtherBlockEnd;

        }

    }

_LIT8(KLit8ShiftJisReplacementForUnconvertibleUnicodeCharacters, "\x81\x48"); // fullwidth question mark

#if defined(_DEBUG)

_LIT(KLitPanicText, "SHIFTJIS_SHARED");

enum TPanic

    {

    EPanicIndexOverflow1=1,

    EPanicIndexOverflow2,

    EPanicNothingToConvert1,

    EPanicNothingToConvert2,

    EPanicOddNumberOfBytes1,

    EPanicOddNumberOfBytes2,

    EPanicBadPointers1,

    EPanicBadPointers2,

    EPanicBadPointers3,

    EPanicBadPointers4,

    EPanicBadPointers5,

    EPanicBadPointers6,

    EPanicBadPointers7,

    EPanicBadPointers8,

    EPanicBadPointers9

    };

LOCAL_C void Panic(TPanic aPanic)

    {

    User::Panic(KLitPanicText, aPanic);

    }

#endif

// TCombinedArrayOfCharacterSets

class TCombinedArrayOfCharacterSets

    {

public:

    TCombinedArrayOfCharacterSets(const TArray<CnvUtilities::SCharacterSet>* aArrayOfAdditionalCharacterSets);

    ~TCombinedArrayOfCharacterSets();

    TArray<CnvUtilities::SCharacterSet> Array() const;

private:

    static TInt CombinedCount(const CBase* aThis);

    static const TAny* CombinedAccessor(const CBase* aThis, TInt aIndex);

private:

    RArray<CnvUtilities::SCharacterSet> iArrayOfCoreCharacterSets;

    const TArray<CnvUtilities::SCharacterSet>* iArrayOfAdditionalCharacterSets;

    };

TCombinedArrayOfCharacterSets::TCombinedArrayOfCharacterSets(const TArray<CnvUtilities::SCharacterSet>* aArrayOfAdditionalCharacterSets)

    :iArrayOfAdditionalCharacterSets(aArrayOfAdditionalCharacterSets)

    {

    if ( FeatureManager::FeatureSupported(KFeatureIdJapanesePicto) )

        {      

        CnvUtilities::SCharacterSet characterSet;

        characterSet.iConversionData=&CnvJisX0201::ConversionData();

        characterSet.iConvertFromIntermediateBufferInPlace=CnvShiftJis::DummyConvertFromIntermediateBufferInPlace;

        characterSet.iEscapeSequence=&KNullDesC8;

        iArrayOfCoreCharacterSets.Append(characterSet);

        characterSet.iConversionData=&CnvJisX0208::ConversionData();

        characterSet.iConvertFromIntermediateBufferInPlace=CnvShiftJis::ConvertFromJisX0208ToShiftJisInPlace;

        characterSet.iEscapeSequence=&KNullDesC8;

        iArrayOfCoreCharacterSets.Append(characterSet);

        SetCharacterSetsForPictograph(iArrayOfCoreCharacterSets, ECharsetShiftJis);

        }

    else

        {            

        CnvUtilities::SCharacterSet characterSet;

        characterSet.iConversionData=&CnvJisX0201::ConversionData();

        characterSet.iConvertFromIntermediateBufferInPlace=CnvShiftJis::DummyConvertFromIntermediateBufferInPlace;

        characterSet.iEscapeSequence=&KNullDesC8;

        iArrayOfCoreCharacterSets.Append(characterSet);

        characterSet.iConversionData=&CnvJisX0208::ConversionData();

        characterSet.iConvertFromIntermediateBufferInPlace=CnvShiftJis::ConvertFromJisX0208ToShiftJisInPlace;

        characterSet.iEscapeSequence=&KNullDesC8;

        iArrayOfCoreCharacterSets.Append(characterSet);

        }

    }

TCombinedArrayOfCharacterSets::~TCombinedArrayOfCharacterSets()

    {

    iArrayOfCoreCharacterSets.Close();

    }

TArray<CnvUtilities::SCharacterSet> TCombinedArrayOfCharacterSets::Array() const

    {

    return TArray<CnvUtilities::SCharacterSet>(CombinedCount, CombinedAccessor, REINTERPRET_CAST(const CBase*, this));

    }

TInt TCombinedArrayOfCharacterSets::CombinedCount(const CBase* aThis)

    {

    const TCombinedArrayOfCharacterSets& thisReference=*REINTERPRET_CAST(const TCombinedArrayOfCharacterSets*, aThis);

    const TInt numberOfCoreCharacterSets=thisReference.iArrayOfCoreCharacterSets.Count();

    if (thisReference.iArrayOfAdditionalCharacterSets!=NULL)

        {

        return numberOfCoreCharacterSets+thisReference.iArrayOfAdditionalCharacterSets->Count();

        }

    return numberOfCoreCharacterSets;

    }

const TAny* TCombinedArrayOfCharacterSets::CombinedAccessor(const CBase* aThis, TInt aIndex)

    {

    const TCombinedArrayOfCharacterSets& thisReference=*REINTERPRET_CAST(const TCombinedArrayOfCharacterSets*, aThis);

    const TInt numberOfCoreCharacterSets=thisReference.iArrayOfCoreCharacterSets.Count();

    if (aIndex>=numberOfCoreCharacterSets)

        {

        __ASSERT_DEBUG(thisReference.iArrayOfAdditionalCharacterSets!=NULL, Panic(EPanicIndexOverflow1));

        return &(*thisReference.iArrayOfAdditionalCharacterSets)[aIndex-numberOfCoreCharacterSets];

        }

    return &thisReference.iArrayOfCoreCharacterSets[aIndex];

    }

// TCombinedArrayOfMethods

class TCombinedArrayOfMethods

    {

public:

    TCombinedArrayOfMethods(const TArray<CnvUtilities::SMethod>* aArrayOfAdditionalMethods);

    ~TCombinedArrayOfMethods();

    TArray<CnvUtilities::SMethod> Array() const;

private:

    static TInt CombinedCount(const CBase* aThis);

    static const TAny* CombinedAccessor(const CBase* aThis, TInt aIndex);

private:

    RArray<CnvUtilities::SMethod> iArrayOfCoreMethods;

    const TArray<CnvUtilities::SMethod>* iArrayOfAdditionalMethods;

    };

TCombinedArrayOfMethods::TCombinedArrayOfMethods(const TArray<CnvUtilities::SMethod>* aArrayOfAdditionalMethods)

    :iArrayOfAdditionalMethods(aArrayOfAdditionalMethods)

    {

    if ( FeatureManager::FeatureSupported(KFeatureIdJapanesePicto) )

        {      

        SetMethodsForPictograph(iArrayOfCoreMethods, ECharsetShiftJis);

        CnvUtilities::SMethod method;

        method.iNumberOfBytesAbleToConvert=CnvShiftJis::NumberOfBytesAbleToConvertToJisX0201;

        method.iConvertToIntermediateBufferInPlace=CnvShiftJis::DummyConvertToIntermediateBufferInPlace;

        method.iConversionData=&CnvJisX0201::ConversionData();

        method.iNumberOfBytesPerCharacter=1;

        method.iNumberOfCoreBytesPerCharacter=1;

        iArrayOfCoreMethods.Append(method);

        method.iNumberOfBytesAbleToConvert=CnvShiftJis::NumberOfBytesAbleToConvertToJisX0208;

        method.iConvertToIntermediateBufferInPlace=CnvShiftJis::ConvertToJisX0208FromShiftJisInPlace;

        method.iConversionData=&CnvJisX0208::ConversionData();

        method.iNumberOfBytesPerCharacter=2;

        method.iNumberOfCoreBytesPerCharacter=2;

        iArrayOfCoreMethods.Append(method);

        }

    else

        {        

        CnvUtilities::SMethod method;

        method.iNumberOfBytesAbleToConvert=CnvShiftJis::NumberOfBytesAbleToConvertToJisX0201;

        method.iConvertToIntermediateBufferInPlace=CnvShiftJis::DummyConvertToIntermediateBufferInPlace;

        method.iConversionData=&CnvJisX0201::ConversionData();

        method.iNumberOfBytesPerCharacter=1;

        method.iNumberOfCoreBytesPerCharacter=1;

        iArrayOfCoreMethods.Append(method);

        method.iNumberOfBytesAbleToConvert=CnvShiftJis::NumberOfBytesAbleToConvertToJisX0208;

        method.iConvertToIntermediateBufferInPlace=CnvShiftJis::ConvertToJisX0208FromShiftJisInPlace;

        method.iConversionData=&CnvJisX0208::ConversionData();

        method.iNumberOfBytesPerCharacter=2;

        method.iNumberOfCoreBytesPerCharacter=2;

        iArrayOfCoreMethods.Append(method);    

        }

    }

TCombinedArrayOfMethods::~TCombinedArrayOfMethods()

    {

    iArrayOfCoreMethods.Close();

    }

TArray<CnvUtilities::SMethod> TCombinedArrayOfMethods::Array() const

    {

    return TArray<CnvUtilities::SMethod>(CombinedCount, CombinedAccessor, REINTERPRET_CAST(const CBase*, this));

    }

TInt TCombinedArrayOfMethods::CombinedCount(const CBase* aThis)

    {

    const TCombinedArrayOfMethods& thisReference=*REINTERPRET_CAST(const TCombinedArrayOfMethods*, aThis);

    const TInt numberOfCoreMethods=thisReference.iArrayOfCoreMethods.Count();

    if (thisReference.iArrayOfAdditionalMethods!=NULL)

        {

        return numberOfCoreMethods+thisReference.iArrayOfAdditionalMethods->Count();

        }

    return numberOfCoreMethods;

    }

const TAny* TCombinedArrayOfMethods::CombinedAccessor(const CBase* aThis, TInt aIndex)

    {

    const TCombinedArrayOfMethods& thisReference=*REINTERPRET_CAST(const TCombinedArrayOfMethods*, aThis);

    const TInt numberOfCoreMethods=thisReference.iArrayOfCoreMethods.Count();

    if (aIndex>=numberOfCoreMethods)

        {

        __ASSERT_DEBUG(thisReference.iArrayOfAdditionalMethods!=NULL, Panic(EPanicIndexOverflow2));

        return &(*thisReference.iArrayOfAdditionalMethods)[aIndex-numberOfCoreMethods];

        }

    return &thisReference.iArrayOfCoreMethods[aIndex];

    }

// CnvShiftJis

EXPORT_C const TDesC8& CnvShiftJis::ReplacementForUnconvertibleUnicodeCharacters()

    {

    return KLit8ShiftJisReplacementForUnconvertibleUnicodeCharacters;

    }

EXPORT_C TInt CnvShiftJis::ConvertFromUnicode(CCnvCharacterSetConverter::TEndianness aDefaultEndiannessOfForeignCharacters, const TDesC8& aReplacementForUnconvertibleUnicodeCharacters, TDes8& aForeign, const TDesC16& aUnicode, CCnvCharacterSetConverter::TArrayOfAscendingIndices& aIndicesOfUnconvertibleCharacters)

    {

    return DoConvertFromUnicode(aDefaultEndiannessOfForeignCharacters, aReplacementForUnconvertibleUnicodeCharacters, aForeign, aUnicode, aIndicesOfUnconvertibleCharacters, NULL);

    }

/**

 * Converts text from Unicode to Shift-JIS (aArrayOfAdditionalCharacterSets provides support

 * for Shift-JIS extensions)

 *

 * @since Internationalization_6.2

 */

EXPORT_C TInt CnvShiftJis::ConvertFromUnicode(CCnvCharacterSetConverter::TEndianness aDefaultEndiannessOfForeignCharacters, const TDesC8& aReplacementForUnconvertibleUnicodeCharacters, TDes8& aForeign, const TDesC16& aUnicode, CCnvCharacterSetConverter::TArrayOfAscendingIndices& aIndicesOfUnconvertibleCharacters, const TArray<CnvUtilities::SCharacterSet>& aArrayOfAdditionalCharacterSets)

    {

    return DoConvertFromUnicode(aDefaultEndiannessOfForeignCharacters, aReplacementForUnconvertibleUnicodeCharacters, aForeign, aUnicode, aIndicesOfUnconvertibleCharacters, &aArrayOfAdditionalCharacterSets);

    }

EXPORT_C TInt CnvShiftJis::ConvertToUnicode(

    CCnvCharacterSetConverter::TEndianness aDefaultEndiannessOfForeignCharacters,

    TDes16& aUnicode, const TDesC8& aForeign,

    TInt& aNumberOfUnconvertibleCharacters,

    TInt& aIndexOfFirstByteOfFirstUnconvertibleCharacter)

    {

    // DummyData converts any pair of bytes into FFFD

    static const SCnvConversionData::SVariableByteData::SRange

        DummyByteLengths = {0, 255, 1, 0};

    static const SCnvConversionData::SOneDirectionData::SRange DummyConv =

        { 0xFFFD, 0xFFFD,

        SCnvConversionData::SOneDirectionData::SRange::EDirect, 2, 0 };

    static const SCnvConversionData DummyData =

        {

        SCnvConversionData::EFixedBigEndian,

        {1, &DummyByteLengths},

        {1, &DummyConv},

        {1, &DummyConv}

        };

    TFixedArray<CnvUtilities::SMethod, 2> nullExtension;

    // First extension converts unrecognised double byte characters to FFFD

    nullExtension[0].iNumberOfBytesAbleToConvert

        = BytesInOtherDoubleByteAreas;

    nullExtension[0].iConvertToIntermediateBufferInPlace

        = CnvShiftJis::DummyConvertToIntermediateBufferInPlace;

    // This conversion data won't do anything for us: it will just get us

    // a load of FFFD, which is what we want.

    nullExtension[0].iConversionData = &DummyData;

    nullExtension[0].iNumberOfBytesPerCharacter = 2;

    nullExtension[0].iNumberOfCoreBytesPerCharacter = 2;

    // Second extension converts any other single byte to FFFD,

    // but only ever one!

    nullExtension[1].iNumberOfBytesAbleToConvert

        = OneIfNotValid;

    nullExtension[1].iConvertToIntermediateBufferInPlace

        = CnvShiftJis::DummyConvertToIntermediateBufferInPlace;

    // This conversion data won't do anything for us: it will just get us

    // a load of FFFD, which is what we want.

    nullExtension[1].iConversionData = &CnvJisX0201::ConversionData();

    nullExtension[1].iNumberOfBytesPerCharacter = 1;

    nullExtension[1].iNumberOfCoreBytesPerCharacter = 1;

    const TArray<CnvUtilities::SMethod> nullExtensionArray = nullExtension.Array();

    return DoConvertToUnicode(aDefaultEndiannessOfForeignCharacters,

        aUnicode, aForeign, aNumberOfUnconvertibleCharacters,

        aIndexOfFirstByteOfFirstUnconvertibleCharacter,

        &nullExtensionArray);

    }

/**

 * Converts text from Shift-JIS to Unicode (aArrayOfAdditionalMethods provides support

 * for Shift-JIS extensions)

 *

 * @since Internationalization_6.2

 */

EXPORT_C TInt CnvShiftJis::ConvertToUnicode(CCnvCharacterSetConverter::TEndianness aDefaultEndiannessOfForeignCharacters, TDes16& aUnicode, const TDesC8& aForeign, TInt& aNumberOfUnconvertibleCharacters, TInt& aIndexOfFirstByteOfFirstUnconvertibleCharacter, const TArray<CnvUtilities::SMethod>& aArrayOfAdditionalMethods)

    {

    return DoConvertToUnicode(aDefaultEndiannessOfForeignCharacters, aUnicode, aForeign, aNumberOfUnconvertibleCharacters, aIndexOfFirstByteOfFirstUnconvertibleCharacter, &aArrayOfAdditionalMethods);

    }

TInt CnvShiftJis::DoConvertFromUnicode(

    CCnvCharacterSetConverter::TEndianness aDefaultEndiannessOfForeignCharacters,

    const TDesC8& aReplacementForUnconvertibleUnicodeCharacters,

    TDes8& aForeign, const TDesC16& aUnicode,

    CCnvCharacterSetConverter::TArrayOfAscendingIndices& aIndicesOfUnconvertibleCharacters,

    const TArray<CnvUtilities::SCharacterSet>* aArrayOfAdditionalCharacterSets)

    {

    TCombinedArrayOfCharacterSets combinedArrayOfCharacterSets(aArrayOfAdditionalCharacterSets);

    return CnvUtilities::ConvertFromUnicode(aDefaultEndiannessOfForeignCharacters, aReplacementForUnconvertibleUnicodeCharacters, aForeign, aUnicode, aIndicesOfUnconvertibleCharacters, combinedArrayOfCharacterSets.Array());

    }

TInt CnvShiftJis::DoConvertToUnicode(

    CCnvCharacterSetConverter::TEndianness aDefaultEndiannessOfForeignCharacters,

    TDes16& aUnicode, const TDesC8& aForeign,

    TInt& aNumberOfUnconvertibleCharacters,

    TInt& aIndexOfFirstByteOfFirstUnconvertibleCharacter,

    const TArray<CnvUtilities::SMethod>* aArrayOfAdditionalMethods)

    {

    TCombinedArrayOfMethods combinedArrayOfMethods(aArrayOfAdditionalMethods);

    TInt unconvert = CnvUtilities::ConvertToUnicodeFromHeterogeneousForeign(

        aDefaultEndiannessOfForeignCharacters, aUnicode, aForeign,

        aNumberOfUnconvertibleCharacters,

        aIndexOfFirstByteOfFirstUnconvertibleCharacter,

        combinedArrayOfMethods.Array());

    // The following is specific impelementation for brower.

    // If brower app calls this API, the yen sign code(0xA5)

    // must be converted to backslash code(0x5C).

    // Becasue Javascript supports backslash code ony.

    TBool browserProcess = (RProcess().SecureId().iId == KBrowserSecureId);

    if (browserProcess && aUnicode.Length() > 0)

        {

        const TUint16* pB = aUnicode.Ptr();

        const TUint16* pbase = pB;

        const TUint16* pE = pB + aUnicode.Length() -1;

        while (pE>=pbase)

            {

            if (*pbase == KCharacterCodeForYenSign)

                {

                aUnicode[pbase - pB] = KCharacterCodeForBackSlash;

                }

            pbase++;

            }

        }

    return unconvert;

    }

void CnvShiftJis::DummyConvertFromIntermediateBufferInPlace(TInt, TDes8&, TInt& aNumberOfCharactersThatDroppedOut)

    {

    aNumberOfCharactersThatDroppedOut=0;

    }

void CnvShiftJis::ConvertFromJisX0208ToShiftJisInPlace(TInt aStartPositionInDescriptor, TDes8& aDescriptor, TInt& aNumberOfCharactersThatDroppedOut)

    {

    aNumberOfCharactersThatDroppedOut=0;

    const TInt descriptorLength=aDescriptor.Length();

    __ASSERT_DEBUG(descriptorLength>aStartPositionInDescriptor, Panic(EPanicNothingToConvert1));

    __ASSERT_DEBUG((descriptorLength-aStartPositionInDescriptor)%2==0, Panic(EPanicOddNumberOfBytes1));

    TUint8* pointerToCurrentByte=CONST_CAST(TUint8*, aDescriptor.Ptr());

    const TUint8* const pointerToLastByte=pointerToCurrentByte+(descriptorLength-1);

    pointerToCurrentByte+=aStartPositionInDescriptor;

    FOREVER

        {

        TUint firstByte=*pointerToCurrentByte-0x21;

        TUint secondByte=*(pointerToCurrentByte+1)-0x21;

        if (firstByte%2!=0)

            {

            secondByte+=94;

            }

        firstByte/=2;

        if (firstByte<KFirstByteRangeFirstBlockLength)

            {

            firstByte+=KFirstByteRangeFirstBlockStart;

            }

        else

            {

            firstByte+=KFirstByteRangeSecondBlockStart-KFirstByteRangeFirstBlockLength;

            }

        if (secondByte<KSecondByteRangeFirstBlockLength)

            {

            secondByte+=KSecondByteRangeFirstBlockStart;

            }

        else

            {

            secondByte+=KSecondByteRangeSecondBlockStart-KSecondByteRangeFirstBlockLength;

            }

        *pointerToCurrentByte=STATIC_CAST(TUint8, firstByte);

        ++pointerToCurrentByte;

        *pointerToCurrentByte=STATIC_CAST(TUint8, secondByte);

        __ASSERT_DEBUG(pointerToCurrentByte<=pointerToLastByte, Panic(EPanicBadPointers1));

        if (pointerToCurrentByte>=pointerToLastByte)

            {

            break;

            }

        ++pointerToCurrentByte;

        }

    }

TInt CnvShiftJis::NumberOfBytesAbleToConvertToJisX0201(const TDesC8& aDescriptor)

    {

    const TUint8* pointerToPreviousByte=aDescriptor.Ptr()-1;

    const TUint8* const pointerToLastByte=pointerToPreviousByte+aDescriptor.Length();

    if (pointerToPreviousByte==pointerToLastByte)

        {

        return 0;

        }

    FOREVER

        {

        __ASSERT_DEBUG(pointerToPreviousByte<pointerToLastByte, Panic(EPanicBadPointers2));

        const TUint currentByte=*(pointerToPreviousByte+1);

        if (((currentByte>KSingleByteRangeFirstBlockEnd) && (currentByte<KSingleByteRangeSecondBlockStart)) ||

            (currentByte>KSingleByteRangeSecondBlockEnd))

            {

            break;

            }

        __ASSERT_DEBUG(pointerToPreviousByte<pointerToLastByte, Panic(EPanicBadPointers3));

        ++pointerToPreviousByte;

        __ASSERT_DEBUG(pointerToPreviousByte<=pointerToLastByte, Panic(EPanicBadPointers4));

        if (pointerToPreviousByte>=pointerToLastByte)

            {

            break;

            }

        }

    return (pointerToPreviousByte+1)-aDescriptor.Ptr();

    }

TInt CnvShiftJis::NumberOfBytesAbleToConvertToJisX0208(const TDesC8& aDescriptor)

    {

    const TUint8* pointerToPreviousByte=aDescriptor.Ptr()-1;

    const TUint8* const pointerToLastByte=pointerToPreviousByte+aDescriptor.Length();

    if (pointerToPreviousByte==pointerToLastByte)

        {

        return 0;

        }

    FOREVER

        {

        __ASSERT_DEBUG(pointerToPreviousByte<pointerToLastByte, Panic(EPanicBadPointers5));

        TUint currentByte=*(pointerToPreviousByte+1);

        if (!IsJisX0208LeadByte(currentByte))

            {

            if (!IsOtherLeadByte(currentByte))

                {

                break;