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IOStreamBuffer

Inherits from:	OSObject
Declared In:	IOStream.h

Overview

A class representing a data buffer that is part of an IOStream.

Functions

getBufferID: Gets the buffer identifier for the IOStreamBuffer object.
getClientReferenceCount
getControlBuffer
getDataBuffer
initWithMemoryDescriptors
receiveClientReference
sendClientReference
setBufferID: Sets the buffer identifier for the IOStreamBuffer object.
setControlBuffer: Sets the control buffer for the IOStreamBuffer object.
setDataBuffer: Sets the data buffer for the IOStreamBuffer object.
withMemoryDescriptors

getBufferID

Gets the buffer identifier for the IOStreamBuffer object.

public

virtual IOStreamBufferID getBufferID(
    void);

Discussion

The buffer identifier is unique across all buffers in a stream.

getClientReferenceCount

public

virtual SInt32 getClientReferenceCount(
    void );

Return Value

The count of client references to this buffer. It may be positive or negative, depending on whether the client is sending data into the kernel, or the kernel is sending data out to the client.

getControlBuffer

public

virtual IOMemoryDescriptor *getControlBuffer(
    void);

Return Value

A pointer to the IOMemoryDescriptor for the control buffer.

getDataBuffer

public

virtual IOMemoryDescriptor *getDataBuffer(
    void);

Return Value

A pointer to the IOMemoryDescriptor for the data buffer.

initWithMemoryDescriptors

public

virtual bool initWithMemoryDescriptors(
    IOMemoryDescriptor *dataBuffer, 
    IOMemoryDescriptor *controlBuffer, 
    IOStreamBufferID bufferID = 0);

receiveClientReference

public

virtual SInt32 receiveClientReference(
    IOByteCount offset = 0,
    IOByteCount length = 0 );

Parameters

offset: The offset in the buffer of the data from the client.
length: The length of the data from the client.

sendClientReference

public

virtual SInt32 sendClientReference(
    IOByteCount offset = 0,
    IOByteCount length = 0 );

Parameters

offset: The offset in the buffer of the data sent to the client.
length: The length of the data sent to the client.

Return Value

The new client reference count.

setBufferID

Sets the buffer identifier for the IOStreamBuffer object.

public

virtual void setBufferID(
    IOStreamBufferID bufferID );

setControlBuffer

Sets the control buffer for the IOStreamBuffer object.

public

virtual void setControlBuffer(
    IOMemoryDescriptor *controlBuffer);

setDataBuffer

Sets the data buffer for the IOStreamBuffer object.

public

virtual void setDataBuffer(
    IOMemoryDescriptor *dataBuffer);

withMemoryDescriptors

public

static IOStreamBuffer *withMemoryDescriptors(
    IOMemoryDescriptor *dataBuffer, 
    IOMemoryDescriptor *controlBuffer, 
    IOStreamBufferID bufferID = 0);

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Last Updated: 2008-12-19