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CFaxT4 Class Reference

class CFaxT4 : public CBase

Fax line coding/decoding.

Provides utility functions for encoding and decoding fax scan lines. The lines can be encoded/decoded as 1 dimensional modified Huffman or 2 dimensional modified Read.

Users must first create a CFaxT4 object using NewL() or NewLC(). Specific functions are provided to encode/decode scan lines using the two coding schemes. In addition, general functions are provided which determine the coding type from the values specified when the object is initialised - using PageInitialise().

In pre-v5.1 releases of Symbian OS, this class was defined in faxstore.h and its import library was faxst2.lib.

Inherits from

CFaxT4
- CBase

Public Member Functions
IMPORT_C TInt	DecodeScanLine(TDes8 &, const TDesC8 &)
IMPORT_C TInt	DecodeScanLine1D(TDes8 &, const TDesC8 &)
IMPORT_C TInt	DecodeScanLine2D(TDes8 &, const TDesC8 &)
IMPORT_C void	EncodeScanLine(const TDesC8 &, TDes8 &)
IMPORT_C void	EncodeScanLine1D(const TDesC8 &, TDes8 &)
IMPORT_C void	EncodeScanLine2D(const TDesC8 &, TDes8 &)
IMPORT_C CFaxT4 *	NewL()
IMPORT_C CFaxT4 *	NewLC()
IMPORT_C void	PageInitialize(TFaxResolution, TFaxCompression, TInt)

Private Member Functions
	CFaxT4()
void	DecodeHuffman(const TDesC8 &)
void	DoEncodeScanLine2D(const TDesC8 &, TDes8 &)

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()

Private Attributes
TFaxCompression	iCompression
const TUint8 *	iEndRef
TInt	iK
TInt	iLineCount
TUint8	iRef
TInt	iReservedFlag2
TFaxResolution	iResolution

Constructor & Destructor Documentation

CFaxT4()

CFaxT4

(

)

[private, inline]

Member Functions Documentation

DecodeHuffman(const TDesC8 &)

void

DecodeHuffman

(

const TDesC8 &

aEncodedScanLine

)

[private]

Parameters

const TDesC8 & aEncodedScanLine

DecodeScanLine(TDes8 &, const TDesC8 &)

IMPORT_C TInt	DecodeScanLine	(	TDes8 &	aScanLine,
			const TDesC8 &	anEncodedScanLine
		)

Decodes a scan line.

The decoding method depends on the compression type specified when the object was initialised - using PageInitialize(). If the object was not initialised, then the scan line is decoded as Modified Huffman.

The fax client can determine the type of compression used in a fax from its header, and can hence use PageInitialize() to set the correct decoding method. KErrUnderflow is returned if the wrong type of compression is specified.

capability: None

Parameters

TDes8 & aScanLine	On return, contains the decoded scan line.
const TDesC8 & anEncodedScanLine	The encoded scan line to be decoded.

DecodeScanLine1D(TDes8 &, const TDesC8 &)

IMPORT_C TInt	DecodeScanLine1D	(	TDes8 &	aScanLine,
			const TDesC8 &	anEncodedScanLine
		)

Decodes a Modified Huffman encoded scan line.

capability: None

Parameters

TDes8 & aScanLine	On return, contains the decoded scan line.
const TDesC8 & anEncodedScanLine	The MH encoded scan line to be decoded.

DecodeScanLine2D(TDes8 &, const TDesC8 &)

IMPORT_C TInt	DecodeScanLine2D	(	TDes8 &	aScanLine,
			const TDesC8 &	anEncodedScanLine
		)

Decodes a Modified Read encoded scan line.

capability: None

Parameters

TDes8 & aScanLine	On return, contains the decoded scan line.
const TDesC8 & anEncodedScanLine	The 2D encoded scan line to be decoded.

DoEncodeScanLine2D(const TDesC8 &, TDes8 &)

void	DoEncodeScanLine2D	(	const TDesC8 &	aScanLine,
			TDes8 &	anEncodedScanLine
		)	[private]

Parameters

const TDesC8 & aScanLine
TDes8 & anEncodedScanLine

EncodeScanLine(const TDesC8 &, TDes8 &)

IMPORT_C void	EncodeScanLine	(	const TDesC8 &	aScanLine,
			TDes8 &	anEncodedScanLine
		)

Encodes a scan line using either one dimensional Modified Huffman (MH) or two dimensional Modified Read (MR) encoding.

The type of encoding used depends on the compression type specified when the object was initialised - using PageInitialize(). If the object was not initialised, then the default compression is MH.

capability: None

Parameters

const TDesC8 & aScanLine	The raw scan line to be encoded.
TDes8 & anEncodedScanLine	On return, contains the encoded scan line.

EncodeScanLine1D(const TDesC8 &, TDes8 &)

IMPORT_C void	EncodeScanLine1D	(	const TDesC8 &	aScanLine,
			TDes8 &	anEncodedScanLine
		)

Encodes a scan line using Modified Huffman compression.

capability: None

Parameters

const TDesC8 & aScanLine	The scan line to be encoded.
TDes8 & anEncodedScanLine	On return, contains the MH encoded scan line.

EncodeScanLine2D(const TDesC8 &, TDes8 &)

IMPORT_C void	EncodeScanLine2D	(	const TDesC8 &	aScanLine,
			TDes8 &	anEncodedScanLine
		)

Encodes a scan line using Modified Read compression.

capability: None

Parameters

const TDesC8 & aScanLine	The scan line to be encoded.
TDes8 & anEncodedScanLine	On return, contains the MR encoded scan line.

NewL()

IMPORT_C CFaxT4 *

NewL

(

)

[static]

Constructs a CFaxT4 object, which provides utility functions to encode and decode fax scan lines.

The function is exactly the same as NewLC() except that the new object is popped from the cleanup stack.

The new object is constructed with the default compression and resolution: EModifiedHuffman and EFaxNormal respectively.

leave: KErrNoMemory There is insufficient memory to perform the operation.

capability: None

NewLC()

IMPORT_C CFaxT4 *

NewLC

(

)

[static]

Constructs a CFaxT4 object, which provides utility functions to encode and decode fax scan lines.

As is usual in Symbian OS, the only difference between this function and NewL() is that this variant pushes the object to the cleanup stack.

The new object is constructed with the default compression and resolution: EModifiedHuffman and EFaxNormal respectively.

leave: KErrNoMemory There is insufficient memory to perform the operation.

capability: None

PageInitialize(TFaxResolution, TFaxCompression, TInt)

IMPORT_C void	PageInitialize	(	TFaxResolution	aResolution,
			TFaxCompression	aCompression,
			TInt	aFlag2 = 0
		)

Initialize fax page, set page parameters.

capability: None

Parameters

TFaxResolution aResolution	defines fax resolution
TFaxCompression aCompression	defines fax compression
TInt aFlag2 = 0	reserved flag.

Member Data Documentation

TFaxCompression iCompression

TFaxCompression

iCompression

[private]

const TUint8 * iEndRef

const TUint8 *

iEndRef

[private]

TInt iK

TInt

[private]

TInt iLineCount

TInt

iLineCount

[private]

TUint8 iRef

TUint8

iRef

[private]

TInt iReservedFlag2

TInt

iReservedFlag2

[private]

TFaxResolution iResolution

TFaxResolution

iResolution

[private]