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SYMBIAN OS V9.4

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#include <utf.h>
Link against: charconv.lib

Class CnvUtfConverter

class CnvUtfConverter;

Description

Converts text between Unicode (UCS-2) and the two Unicode transformation formats UTF-7 and UTF-8. There are no functions to convert directly between UTF-7 and UTF-8.

Objects of this class do not need to be created because all the member functions are static. The four functions are passed text in the second argument and output the resulting text in the first argument. Sixteen-bit descriptors are used to hold text encoded in UCS-2 (i.e. normal 16 bit Unicode), and eight-bit descriptors are used to hold text encoded in either of the transformation formats.

The conversion functions return the number of characters which were not converted because the output descriptor was not long enough to hold all of the converted text. This allows users of this class to perform partial conversions on an input descriptor, handling the case when the input descriptor is truncated mid way through a multi-byte character. The caller does not have to guess how big to make the output descriptor for a given input descriptor- they can simply do the conversion in a loop using a small output descriptor. The ability to handle truncated descriptors is particularly useful if the caller is receiving information in chunks from an external source.

Members

Defined in CnvUtfConverter:

Member functions

ConvertFromUnicodeToUtf7(TDes8 &,const TDesC16 &,TBool)

IMPORT_C static TInt ConvertFromUnicodeToUtf7(TDes8 &aUtf7, const TDesC16 &aUnicode, TBool aEncodeOptionalDirectCharactersInBase64);

Description

Converts Unicode text into UTF-7 encoding.

Parameters

TDes8 &aUtf7

On return, contains the UTF-7 encoded output string.

const TDesC16 &aUnicode

A UCS-2 encoded input string.

TBool aEncodeOptionalDirectCharactersInBase64

If ETrue then characters from UTF-7 set O (optional direct characters) are encoded in Modified Base64. If EFalse the characters are encoded directly, as their ASCII equivalents.

Return value

TInt

The number of unconverted characters left at the end of the input descriptor, or one of the error values defined in TError.

ConvertFromUnicodeToUtf8(TDes8 &,const TDesC16 &)

IMPORT_C static TInt ConvertFromUnicodeToUtf8(TDes8 &aUtf8, const TDesC16 &aUnicode);

Description

Converts Unicode text into UTF-8 encoding.

Parameters

TDes8 &aUtf8

On return, contains the UTF-8 encoded output string.

const TDesC16 &aUnicode

The Unicode-encoded input string.

Return value

TInt

The number of unconverted characters left at the end of the input descriptor, or one of the error values defined in TError.

ConvertToUnicodeFromUtf7(TDes16 &,const TDesC8 &,TInt &)

IMPORT_C static TInt ConvertToUnicodeFromUtf7(TDes16 &aUnicode, const TDesC8 &aUtf7, TInt &aState);

Description

Converts text encoded using the Unicode transformation format UTF-7 into the Unicode UCS-2 character set.

If the conversion is achieved using a series of calls to this function, where each call starts off where the previous call reached in the input descriptor, the state of the conversion is stored. The initial value of the state variable should be set as KStateDefault when the conversion is started, and afterwards simply passed unchanged into each function call.

Parameters

TDes16 &aUnicode

On return, contains the Unicode encoded output string.

const TDesC8 &aUtf7

The UTF-7 encoded input string.

TInt &aState

For the first call of the function set to KStateDefault. For subsequent calls, pass in the variable unchanged.

Return value

TInt

The number of unconverted bytes left at the end of the input descriptor, or one of the error values defined in TError.

ConvertToUnicodeFromUtf8(TDes16 &,const TDesC8 &)

IMPORT_C static TInt ConvertToUnicodeFromUtf8(TDes16 &aUnicode, const TDesC8 &aUtf8);

Description

Converts text encoded using the Unicode transformation format UTF-8 into the Unicode UCS-2 character set.

Parameters

TDes16 &aUnicode

On return, contains the Unicode encoded output string.

const TDesC8 &aUtf8

The UTF-8 encoded input string

Return value

TInt

The number of unconverted bytes left at the end of the input descriptor, or one of the error values defined in TError.

ConvertFromUnicodeToUtf7L(const TDesC16 &,TBool)

IMPORT_C static HBufC8* ConvertFromUnicodeToUtf7L(const TDesC16 &aUnicode, TBool aEncodeOptionalDirectCharactersInBase64);

Description

Converts Unicode text into UTF-7 encoding. The fucntion leaves with KErrCorrupt if the input string is corrupt.

Parameters

const TDesC16 &aUnicode

A UCS-2 encoded input string.

TBool aEncodeOptionalDirectCharactersInBase64

If ETrue then characters from UTF-7 set O (optional direct characters) are encoded in Modified Base64. If EFalse the characters are encoded directly, as their ASCII equivalents.

Return value

HBufC8 *

A descriptor containing the UTF-7 encoded output string.

ConvertFromUnicodeToUtf8L(const TDesC16 &)

IMPORT_C static HBufC8* ConvertFromUnicodeToUtf8L(const TDesC16 &aUnicode);

Description

Converts Unicode text into UTF-8 encoding.

The variant of UTF-8 used internally by Java differs slightly from standard UTF-8. The TBool argument controls the UTF-8 variant generated by this function. This function leaves with a KErrCorrupt if the input string is corrupt.

Parameters

const TDesC16 &aUnicode

A UCS-2 encoded input string.

Return value

HBufC8 *

A pointer to an HBufC8 containing the converted UTF8.

ConvertToUnicodeFromUtf7L(const TDesC8 &)

IMPORT_C static HBufC16* ConvertToUnicodeFromUtf7L(const TDesC8 &aUtf7);

Description

Converts text encoded using the Unicode transformation format UTF-7 into the Unicode UCS-2 character set.

Parameters

const TDesC8 &aUtf7

The UTF-7 encoded input string.

Return value

HBufC16 *

A pointer to an HBufC16 containing the converted Unicode string

ConvertToUnicodeFromUtf8L(const TDesC8 &)

IMPORT_C static HBufC16* ConvertToUnicodeFromUtf8L(const TDesC8 &aUtf8);

Description

Converts text encoded using the Unicode transformation format UTF-8 into the Unicode UCS-2 character set. This function leaves with an error code of the input string is corrupted.

Parameters

const TDesC8 &aUtf8

The UTF-8 encoded input string

Return value

HBufC16 *

A pointer to an HBufC16 with the converted Unicode string.

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Member enumerations

Enum TError

TError

Description

Conversion error flags. At this stage there is only one error flag

EErrorIllFormedInput

The input descriptor contains a single corrupt character. This might occur when the input descriptor only contains some of the bytes of a single multi-byte character.

Enum anonymous

n/a

Description

Initial value for the state argument in a set of related calls to ConvertToUnicode().

KStateDefault

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