CResourceFile Class Reference

#include <barsc2.h>

class CResourceFile : public CBase

Inherits from

CResourceFile

Public Member Functions
virtual	~CResourceFile()
IMPORT_C HBufC8 *	AllocReadL(TInt)
IMPORT_C HBufC8 *	AllocReadLC(TInt)
IMPORT_C void	ConfirmSignatureL(TInt)
IMPORT_C void	ConfirmSignatureL()
IMPORT_C CResourceFile *	NewL(RFs &, const TDesC &, TUint, TInt)
IMPORT_C CResourceFile *	NewL(const TDesC8 &)
IMPORT_C CResourceFile *	NewLC(RFs &, const TDesC &, TUint, TInt)
IMPORT_C TInt	Offset()
IMPORT_C TBool	OwnsResourceIdL(TInt)
IMPORT_C void	ReadL(TDes8 &, TInt)
IMPORT_C TInt	SignatureL()
IMPORT_C TUidType	UidType()

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()

Detailed Description

Accesses a resource file or resource file buffer and reads the resource data into a buffer.

Interpretation of the data is achieved using the RResourceReader class. CResourceFile methods behaviour when some problem occurs - it leaves with an error code. Most of the time the error code will be KErrCorrupt.

Constructor & Destructor Documentation

~CResourceFile ( )

IMPORT_C

~CResourceFile

(

)

[virtual]

Frees the resources, allocated by the instance.

Member Function Documentation

AllocReadL ( TInt )

IMPORT_C HBufC8 *

AllocReadL

(

TInt

aResourceId

)

const

Reads a resource into a heap descriptor and returns a pointer to that descriptor.

A heap descriptor of appropriate length is allocated for the resource. Ownership of the heap descriptor passes to the caller who must destroy it when it is no longer needed.

The search for the resource uses the following algorithm:

A resource id in the range 1 to 4095 is looked up in this resource file. The function leaves if there is no matching resource.

If the resource id is greater than 4095, then the most significant 20 bits of the resource id is treated as an offset and the least significant 12 bits is treated as the real resource id. If the offset matches the offset value defined for this file, then the resource is looked up in this resource file using the real resource id (i.e. the least significant 12 bits). If the offset does not match, then the function leaves.

Note, do not call this function until a call to ConfirmSignatureL() has completed successfully.

leave: The function leaves if this resource id is not in this resource file or the file is corrupted.

Parameter	Description
aResourceId	The numeric id of the resource to be read.

AllocReadLC ( TInt )

IMPORT_C HBufC8 *

AllocReadLC

(

TInt

aResourceId

)

const

Reads a resource into a heap descriptor, returns a pointer to that descriptor and pushes the pointer onto the cleanup stack.

A heap descriptor of appropriate length is allocated for the resource. Ownership of the heap descriptor passes to the caller who must destroy it and pop its pointer off the cleanup stack when it is no longer needed.

The search for the resource uses the following algorithm:

A resource id in the range 1 to 4095 is looked up in this resource file. The function leaves if there is no matching resource.

Note, do not call this function until a call to ConfirmSignatureL() has completed successfully.

leave: The function leaves if this resource id is not in this resource file or the file is corrupted.

Parameter	Description
aResourceId	The numeric id of the resource to be read.

ConfirmSignatureL ( TInt )

IMPORT_C void

ConfirmSignatureL

(

TInt

aSignature

)

Initialises the offset value from the first resource.

The function assumes that the first resource in the file consists of two 32-bit integers. The first integer contains the version number and the second is a self-referencing link whose value is the offset for the resources in the file, plus 1.This function must be called before calling Offset(), AllocReadL(), AllocReadLC() or ReadL().

leave: The function leaves if this resource id is not in this resource file or the file is corrupted.

Parameter	Description
aSignature	This argument value is not used by the function.

ConfirmSignatureL ( )

IMPORT_C void

ConfirmSignatureL

(

)

Initialises the offset value from the first resource.

The function tests to catch cases where the first resource is not an RSS_SIGNATURE. It assumes that the first resource in the file consists of two 32-bit integers. The first integer contains the version number and the second is a self-referencing link whose value is the offset for the resources in the file, plus 1.This function must be called before calling Offset(), AllocReadL(), AllocReadLC() or ReadL().

leave: The function leaves if this resource id is not in this resource file or the file is corrupted.

NewL ( RFs &, const TDesC &, TUint, TInt )

IMPORT_C CResourceFile *	NewL	(	RFs &	aFs,
			const TDesC &	aName,
			TUint	aFileOffset,
			TInt	aFileSize
		)	[static]

Creates CResourceFile instance.

leave: KErrCorrupt if the file is corrupted.

leave: KErrNoMemory if there is not enough memory for the object.

Parameter	Description
aFs	Handle to a file server session.
aName	File to open as a resource file.
aFileOffset	The resource file section offset from the beginning of the file.
aFileSize	The resource file section size.

NewL ( const TDesC8 & )

IMPORT_C CResourceFile *

NewL

(

const TDesC8 &

aRscFileBuffer

)

[static]

Creates CResourceFile instance.

leave: KErrCorrupt if the file buffer is corrupted.

leave: KErrNoMemory if there is not enough memory for the object.

Parameter	Description
aRscFileBuffer	a buffer containing one entire resource file

Returns: a CResourceFile instance corresponding to the rsc file passed through the file buffer

NewLC ( RFs &, const TDesC &, TUint, TInt )

IMPORT_C CResourceFile *	NewLC	(	RFs &	aFs,
			const TDesC &	aName,
			TUint	aFileOffset,
			TInt	aFileSize
		)	[static]

Creates CResourceFile instance.

leave: KErrCorrupt if the file is corrupted.

leave: KErrNoMemory if there is not enough memory for the object.

Parameter	Description
aFs	Handle to a file server session.
aName	File to open as a resource file.
aFileOffset	The resource file section offset from the beginning of the file.
aFileSize	The resource file section size.

Offset ( )

IMPORT_C TInt

Offset

(

)

const

Returns the offset value defined for this resource file.

This function must not be called until a call to ConfirmSignatureL() has completed successfully, otherwise the value returned by this function may be meaningless.

Returns: The offset value defined for this resource file.

OwnsResourceIdL ( TInt )

IMPORT_C TBool

OwnsResourceIdL

(

TInt

aResourceId

)

const

Tests whether the resource file owns the specified resource id. The resource file owns the resource id if the most significant 20 bits of the resource id are zero or match the offset value as returned from a call to the Offset() member function or if the resource id is not out of range.

leave: KErrCorrupt - the file is corrupted. Some other error codes are possible.

Parameter	Description
aResourceId	The resource id to test.

Returns: True, if the resource file owns the id, false otherwise.

ReadL ( TDes8 &, TInt )

IMPORT_C void	ReadL	(	TDes8 &	aDes,
			TInt	aResourceId
		)	const

Reads a resource specified by resource id into the specified descriptor.

The descriptor must be long enough to contain the entire resource

The search for the resource uses the following algorithm:

A resource id in the range 1 to 4095 is looked up in this resource file. The function leaves if there is no matching resource.

Note, do not call this function until a call to ConfirmSignatureL() has completed successfully.

leave: The function leaves if this resource id is not in this resource file or the file is corrupted.

Parameter	Description
aDes	On return, contains the resource that has been read. The function leaves if the descriptor is not long enough to contain the entire resource.
aResourceId	The numeric id of the resource to be read. The function leaves if this resource id is not in this resource file.

SignatureL ( )

IMPORT_C TInt

SignatureL

(

)

const

Returns this resource file's version number.

The function assumes that the first resource in the file consists of two 32-bit integers. The first integer contains the version number.

leave: KErrCorrupt - the file is corrupted.

Returns: The version number.

UidType ( )

IMPORT_C TUidType

UidType

(

)

const

Returns this resource file's UIDs.

Returns: The UIDs of the loaded resource file.