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RResourceFile Class Reference

class RResourceFile

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

Interpretation of the data is achieved using the TResourceReader class.

RResourceFile instance behaviour when some problem occurs - it panics. Or asserts, if the used method is not "L" method.

Expected behaviour when assignment operator or copy constructor is called: The class doesn't have assignment operator and copy constructor, so the compiler generated ones will be used. The heap buffers used by the source class instance will be shared with the destination class instance.

Expected behaviour when the RResourceFile instance is about to be destroyed: The class doesn't have destructor so compiler generated one will be used. Always call Close() to free allocated by the instance resources.

TResourceReader

Public Member Functions
	RResourceFile()
IMPORT_C HBufC8 *	AllocReadL(TInt)
IMPORT_C HBufC8 *	AllocReadLC(TInt)
IMPORT_C void	Close()
IMPORT_C void	ConfirmSignatureL(TInt)
IMPORT_C void	ConfirmSignatureL()
TInt	Offset()
IMPORT_C void	OpenL(RFs &, const TDesC &)
IMPORT_C void	OpenL(RFs &, const TDesC &, TUint, TInt)
IMPORT_C TBool	OwnsResourceId(TInt)
IMPORT_C TBool	OwnsResourceIdL(TInt)
IMPORT_C void	ReadL(TDes8 &, TInt)
IMPORT_C TInt	SignatureL()
IMPORT_C TUidType	UidType()

Private Member Functions
void	DoOpenL(RFs &, const TDesC &, TUint, TInt)
RResourceFileImpl *	Impl()
const RResourceFileImpl *	Impl()
IMPORT_C TInt	Offset2()

Private Member Enumerations
enum	anonymous { KRscFileSize = 24 }

Private Attributes
TUint8	iImpl

Constructor & Destructor Documentation

RResourceFile()

IMPORT_C

RResourceFile

(

)

Constructs a default resource file object.

Member Functions 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: KErrNotFound - there is no resource with aResourceId in the file.

panic: If the file is corrupted - the method will panic in debug mode.

RResourceFile::Offset() TBafPanic for panic codes.

Parameters

TInt 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: KErrNotFound - there is no resource with aResourceId in the file.

panic: If the file is corrupted - the method will panic in debug mode.

RResourceFile::Offset() TBafPanic for panic codes.

Parameters

TInt aResourceId

The numeric id of the resource to be read.

Close()

IMPORT_C void

(

)

Closes the resource file reader. This function is called after finishing reading all resources.

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: KErrCorrupt - wrong size of the first resource in the file. Probably the file is corrupted.

panic: If the file is corrupted - the method will panic in debug mode.

TBafPanic for panic codes.

Parameters

TInt 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: KErrCorrupt - wrong size of the first resource in the file. Probably the file is corrupted.

panic: If the file is corrupted - the method will panic in debug mode.

TBafPanic for panic codes.

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

void	DoOpenL	(	RFs &	aFs,
			const TDesC &	aName,
			TUint	aFileOffset,
			TInt	aFileSize
		)	[private]

Opens the resource file reader.

leave: The function leaves if the named file cannot be opened or the header record at the beginning of the file cannot be read.

panic: If the file is corrupted - the method will panic in debug mode.

TBafPanic for panic codes.

Parameters

RFs & aFs	Handle to a file server session.
const TDesC & aName	File to open as a resource file.
TUint aFileOffset	Resource file section offset from the beginning of the file.
TInt aFileSize	Resource file section size.

Impl()

RResourceFileImpl *

Impl

(

)

[private]

The method returns a pointer to the object implementing resource file reader functionality.

Impl()

const RResourceFileImpl *

Impl

(

)

const [private]

The method returns a const pointer to the object implementing resource file reader functionality.

Offset()

TInt

Offset

(

)

const [inline]

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.

RResourceFile::ConfirmSignatureL()

Offset2()

IMPORT_C TInt

Offset2

(

)

const [private]

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.

OpenL(RFs &, const TDesC &)

IMPORT_C void	OpenL	(	RFs &	aFs,
			const TDesC &	aName
		)

Opens the resource file reader.

The resource file reader must be opened before reading resources or checking the signature of the resource file. This function initially closes the resource-file object if it is currently open. If a leave occurs during the function, the object is reverted to its closed state.

leave: The function leaves if the named file cannot be opened or the header record at the beginning of the file cannot be read.

panic: If the file is corrupted - the method will panic in debug mode.

TBafPanic for panic codes.

Parameters

RFs & aFs	Handle to a file server session.
const TDesC & aName	File to open as a resource file

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

IMPORT_C void	OpenL	(	RFs &	aFs,
			const TDesC &	aName,
			TUint	aFileOffset,
			TInt	aFileSize
		)

Opens the resource file reader.

leave: Function leaves if the named file cannot be opened or the header record at the beginning of the file cannot be read.

panic: If the file is corrupted - the method will panic in debug mode.

TBafPanic for panic codes.

Parameters

RFs & aFs	Handle to a file server session
const TDesC & aName	File to open as a resource file
TUint aFileOffset	Resource file section offset from the beginning of the file.
TInt aFileSize	Resource file section size.

OwnsResourceId(TInt)

IMPORT_C TBool

OwnsResourceId

(

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. Interface is deprecated because it is unsafe as it may leave. RResourceFile::OwnsResourceIdL

Parameters

TInt aResourceId

The resource id to test or if the resource id is not out of range.

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.

panic: If the file is corrupted - the method will panic in debug mode.

TBafPanic for panic codes.

Parameters

TInt aResourceId

The resource id to test.

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.

panic: If the file is corrupted - the method will panic in debug mode.

TBafPanic for panic codes.

Parameters

TDes8 & 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.
TInt aResourceId	The numeric id of the resource to be read.

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 Wrong size of the first resource in the file. Probably the file is corrupted.

panic: If the file is corrupted - the method will panic in debug mode.

RResourceFile::ConfirmSignatureL() TBafPanic for panic codes.

UidType()

IMPORT_C TUidType

UidType

(

)

const

Retrieve the UID tuple of the opened resource file.

Pre-condition: OpenL() has been called successfully.

panic: If the file is not opened or class data members initialization fails - the method will panic always.

TBafPanic for panic codes.

Member Enumerations Documentation

Enum anonymous

Enumerators

KRscFileSize = 24

Member Data Documentation

TUint8 iImpl

TUint8

iImpl

[private]