com.groovemanager.spi.asio
Class DoubleHalfRingBuffer

java.lang.Object
  com.groovemanager.spi.asio.DoubleHalfRingBuffer

 class DoubleHalfRingBuffer
extends Object

A RingBuffer to be used with DoubleHalfBuffers.

Author:

Manu Robledo

Field Summary

private int	granularity The granularity in which data must be read or written.
private boolean	open Indicates whether this buffer is in open state or not
private DoubleHalfBuffer	readBuffer A view to the source buffer used for reading
private boolean	writeAhead When read and write position are the same, this value indicates, whether the buffer is filled completely (false) or emptied completely (true)
private DoubleHalfBuffer	writeBuffer A view to the source buffer used for reading

Constructor Summary

DoubleHalfRingBuffer(DoubleHalfBuffer buffer, int granularity)
Construct a new DoubleHalfRingBuffer out of the given buffer

Method Summary

void	close() Close this buffer
void	flush() Empty this buffer
boolean	isOpen() Tells whether this buffer is currently open or not
void	open() Open this buffer
int	read(byte[] b, int off, int len) Try to read len bytes from this buffer starting at the current position into b starting at position off.
int	read(byte[] b, int off, int len, boolean overwrite) Try to read len bytes from this buffer starting at the current position into b starting at position off.
int	readAvailable() Get the number of bytes currently available for reading
void	rewind() Rewind this buffer
void	setPositions(int readPos, int writePos, boolean writeAhead) Set the read and write position of this Buffer
int	size() Get this buffer´s total size
int	write(byte[] b, int off, int len) Try to write len bytes from b starting at index off into this buffer starting at the current position.
int	write(byte[] b, int off, int len, boolean overwrite) Try to write len bytes from b starting at index off into this buffer starting at the current position.
int	writeAvailable() Get the number of bytes currently available for writing

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

writeAhead

private boolean writeAhead

When read and write position are the same, this value indicates, whether the buffer is filled completely (false) or emptied completely (true)

open

private boolean open

Indicates whether this buffer is in open state or not

granularity

private final int granularity

The granularity in which data must be read or written. Data will only be available in blocks of this value.

readBuffer

private final DoubleHalfBuffer readBuffer

A view to the source buffer used for reading

writeBuffer

private final DoubleHalfBuffer writeBuffer

A view to the source buffer used for reading

Constructor Detail

DoubleHalfRingBuffer

public DoubleHalfRingBuffer(DoubleHalfBuffer buffer,
                            int granularity)

Construct a new DoubleHalfRingBuffer out of the given buffer

Parameters:

buffer - The buffer to be used as source for this ring buffer

granularity - The buffer granularity in bytes

Method Detail

readAvailable

public int readAvailable()

Get the number of bytes currently available for reading

Returns:

The number of bytes avilable for reading

writeAvailable

public int writeAvailable()

Get the number of bytes currently available for writing

Returns:

The number of bytes available for writing

read

public int read(byte[] b,
                int off,
                int len)

Try to read len bytes from this buffer starting at the current position into b starting at position off. The currently avilable bytes will be read the number of bytes read will be returned.

Parameters:

b - The byte array to transfer the data to

off - The offset inside the target array

len - The number of bytes to read

Returns:

The number of bytes read

read

public int read(byte[] b,
                int off,
                int len,
                boolean overwrite)

Try to read len bytes from this buffer starting at the current position into b starting at position off. If overwrite is true, the bytes will be read independent of the number of available bytes for reading. If this read operation exceeds the current write position (buffer underrun), the write position will be discarded and set to the end of the read data.

Parameters:

b - The byte array to transfer the data to

off - The offset inside the target array

len - The number of bytes to read

overwrite - true, if the given number of bytes should be read even if this causes a buffer underrun

Returns:

The number of bytes read

write

public int write(byte[] b,
                 int off,
                 int len)

Try to write len bytes from b starting at index off into this buffer starting at the current position. This method will not return before the given number of bytes has been written or the buffer has been closed. This means that if the given number of bytes can not be written at once, this methods waits until another thread empties the needed part of this buffer by reading from it.

Parameters:

b - The array containing the data to write

off - Start position inside the given array

len - The number of bytes to write

Returns:

The number of bytes written

write

public int write(byte[] b,
                 int off,
                 int len,
                 boolean overwrite)

Try to write len bytes from b starting at index off into this buffer starting at the current position. This method will not return before the given number of bytes has been written or the buffer has been closed. If overwrite is set to true, this method will write the data immediately independent of the number of bytes available for writing. If the read position is exceeded by this operation (buffer overflow), the read position will be set after the last written data.

Parameters:

b - The array containing the data to write

off - Start position inside the given array

len - The number of bytes to write

overwrite - true, if the given number of bytes should be written even if this causes a buffer overflow

Returns:

The number of bytes written

open

public void open()

Open this buffer

isOpen

public boolean isOpen()

Tells whether this buffer is currently open or not

Returns:

true, if this buffer is open, false otherwise

close

public void close()

Close this buffer

size

public int size()

Get this buffer´s total size

Returns:

This buffer´s total size in bytes

flush

public void flush()

Empty this buffer

rewind

public void rewind()

Rewind this buffer

setPositions

public void setPositions(int readPos,
                         int writePos,
                         boolean writeAhead)

Set the read and write position of this Buffer

Parameters:

readPos - The new read position

writePos - The new write position

writeAhead - Only needed, if readPos == writePos:
true, if the writePos is ahead of the readPos and the buffer is therefore filled, false if the buffer is empty.