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CConverterBase Class Reference

class CConverterBase : public CBase

For Ecom Style Converters i.e.,for v9.1 and above CConverterBase2 should be used.

Polymorphic interface for converters from one data format to another.

Clients use this interface to access data converters. The implementator of a data converter derives a class from this in which to implement the appropriate conversion functionality.

The interface offers conversions between files, and between objects that support the stream interfaces, e.g. stream stores.

There are two flavours of conversion methods:

the synchronous interfaces, ConvertL() and ConvertObjectL(), which perform the specified conversion and then return

the asynchronous interfaces, ConvertAL() and ConvertObjectAL(), which initialise the converter object, and allow the client code to call DoConvertL() a number of times until the conversion is complete or abandoned.

CConverterBase2

Inherits from

CConverterBase
- CBase

Public Member Functions
IMPORT_C void	CancelConvert()
IMPORT_C TInt	Capabilities()
IMPORT_C void	ConvertAL(const TFileName &, const TFileName &, MConverterUiObserver *)
IMPORT_C void	ConvertL(const TFileName &, const TFileName &, MConverterUiObserver *)
IMPORT_C void	ConvertObjectAL(RReadStream &, RWriteStream &, MConverterUiObserver *)
IMPORT_C void	ConvertObjectL(RReadStream &, RWriteStream &, MConverterUiObserver *)
IMPORT_C TBool	DoConvertL()
IMPORT_C CConverterBase *	EmbeddedObjectL(TDataType &)
IMPORT_C void	ExtendedInterfaceL(TUid, CBase *&)
IMPORT_C TBool	GetEmbeddedFileName(TFileName &)
TUid	Uid()

Inherited Functions
	CBase::CBase()
	CBase::Delete(CBase *)
	CBase::Extension_(TUint,TAny &,TAny )
	CBase::operator new(TUint)
	CBase::operator new(TUint,TAny *)
	CBase::operator new(TUint,TLeave)
	CBase::operator new(TUint,TLeave,TUint)
	CBase::operator new(TUint,TUint)
	CBase::~CBase()

Public Member Enumerations
enum	TCapability { EConvertsFiles = 0x01, EConvertsObjects = 0x02, EConvertsExtract = 0x04 }

Member Functions Documentation

CancelConvert()

IMPORT_C void

CancelConvert

(

)

[virtual]

Cleans up a conversion that has been prepared or is in progress.

It should free any resources and reset the converter object to an initial state.

The default is to do nothing.

Capabilities()

IMPORT_C TInt

Capabilities

(

)

[virtual]

Gets the converter's capabilities.

The default is to return a bitmask of all the TCapability flags.

ConvertAL(const TFileName &, const TFileName &, MConverterUiObserver *)

IMPORT_C void	ConvertAL	(	const TFileName &	aSourceFile,
			const TFileName &	aTargetFile,
			MConverterUiObserver *	aObserver = NULL
		)	[virtual]

Prepares for conversion in multiple steps of a file.

Clients must call this function before calling DoConvertL() one or more times to do the conversion. The function can call back the MaxSteps() function of the supplied MConverterUiObserver to tell the client the maximum number of calls to DoConvertL() that will be required.

The rest of this description describes how to implement this function.

The function should initialise the object before performing a conversion, but should not do the conversion itself. Such initialisation should include:

storing the MConverterUiObserver pointer (if supplied), so the client can later be notified of conversion progress

validating the integrity of the input data

optionally, creating the appropriate application engine, either for input or output, to enable access to the data

determining the number of steps (i.e. calls to DoConvertL()) required to perform the conversion and pass this to the client by calling MConverterUiObserver::MaxSteps()

The default implementation leaves with KErrNotSupported.

leave: KErrNotSupported File conversion is not supported

Parameters

const TFileName & aSourceFile	File to convert
const TFileName & aTargetFile	File to which to write the converted output. The file can be overwritten if it already exists.
MConverterUiObserver * aObserver = NULL	Observer of the conversion process

ConvertL(const TFileName &, const TFileName &, MConverterUiObserver *)

IMPORT_C void	ConvertL	(	const TFileName &	aSourceFile,
			const TFileName &	aTargetFile,
			MConverterUiObserver *	aObserver = NULL
		)	[virtual]

Converts a file in a single step.

The caller can supply a MConverterUiObserver to be informed of progress in the conversion.

The default implementation calls ConvertAL() to prepare the object to perform the conversion, and then calls DoConvertL() in a loop until conversion is complete.

leave: KErrNotSupported File conversion is not supported

Parameters

const TFileName & aSourceFile	File to convert
const TFileName & aTargetFile	File to which to write the converted output
MConverterUiObserver * aObserver = NULL	Optional observer of the conversion process

ConvertObjectAL(RReadStream &, RWriteStream &, MConverterUiObserver *)

IMPORT_C void	ConvertObjectAL	(	RReadStream &	aReadStream,
			RWriteStream &	aWriteStream,
			MConverterUiObserver *	aObserver = NULL
		)	[virtual]

Prepares for conversion in multiple steps of a stream object.

For a description of how to implement this function, see ConvertAL().

leave: KErrNotSupported Stream object conversion is not supported

Parameters

RReadStream & aReadStream	Stream from which to read the data to convert
RWriteStream & aWriteStream	Stream to which to write the converted data
MConverterUiObserver * aObserver = NULL	Optional observer of the conversion process

ConvertObjectL(RReadStream &, RWriteStream &, MConverterUiObserver *)

IMPORT_C void	ConvertObjectL	(	RReadStream &	aReadStream,
			RWriteStream &	aWriteStream,
			MConverterUiObserver *	aObserver = NULL
		)	[virtual]

Converts a stream object in a single step.

The caller can supply a MConverterUiObserver to be informed of progress in the conversion.

The default implementation calls ConvertObjectAL() to prepare the object to perform the conversion, and then calls DoConvertL() in a loop until conversion is complete.

Parameters

RReadStream & aReadStream	Stream from which to read the data to convert
RWriteStream & aWriteStream	Stream to which to write the converted data
MConverterUiObserver * aObserver = NULL	Optional observer of the conversion process

DoConvertL()

IMPORT_C TBool

DoConvertL

(

)

[virtual]

Performs a step in converting the data.

The function advances a step in converting the data each time that it is called. When conversion is complete, the function returns EFalse.

EmbeddedObjectL(TDataType &)

IMPORT_C CConverterBase *

EmbeddedObjectL

(

TDataType &

aType

)

[virtual]

Gets a converter for an embedded object of the specified type.

The default is to return NULL.

Parameters

TDataType & aType

Type of the embedded object

ExtendedInterfaceL(TUid, CBase *&)

IMPORT_C void	ExtendedInterfaceL	(	TUid	aInterfaceUid,
			CBase *&	aInterface
		)	[virtual]

Allows licensees to extend the Converter Architecture API.

This function replaces the private Reserved_1() function, so the change is binary compatible with v7.0.

If overridden by the converter, it allows third party code to request the extended interface object by UID. If not overridden, the default implementation does nothing.

Parameters

TUid aInterfaceUid	A UID that identifies the required extended interface object.
CBase *& aInterface	On return, an object that extends the Converter Architecture interface, or NULL, if the UID specified is not recognised.

GetEmbeddedFileName(TFileName &)

IMPORT_C TBool

GetEmbeddedFileName

(

TFileName &

aFileName

)

[virtual]

Gets a filename embedded in the object.

Parameters

TFileName & aFileName

The file name found

Uid()

TUid

Uid

(

)

[pure virtual]

Gets the converter's UID.

Member Enumerations Documentation

Enum TCapability

Bitmask values that describe the capabilities of the converter.

Enumerators

EConvertsFiles = 0x01	The converter can convert files.
EConvertsObjects = 0x02	The converter can convert stream objects.
EConvertsExtract = 0x04	The converter can extract embedded objects.