org.blinkenbyte.io
Class ByteArrayBuffer

java.lang.Object
  java.io.OutputStream
      org.blinkenbyte.io.ByteArrayBuffer

All Implemented Interfaces:

java.io.Closeable, java.io.Flushable

public class ByteArrayBuffer
extends java.io.OutputStream

This class represents an output stream that uses two-dimensional byte arrays for storage. This allows it to allocate storage space incrementally without the usual create/copy cycle usually needed to expand an array. It also supports creating an InputStream that can read directly from the byte arrays.

Nested Class Summary

static class

ByteArrayBuffer.ByteArrayBufferInputStream Class that can extends InputStream and can read directly from the internal buffers of the host ByteArrayBuffer.

Field Summary

protected int	bytesUsed The number of bytes currently used.
protected int	MAIN_BUFFER_SIZE The size of the main buffer.
protected byte[][]	mainBuffer The main buffer.
protected int	mainBuffersAllocated The number of buffers allocated in the main buffer.
protected int	SUB_BUFFER_LOG The base 2 logarithm of the size of the sub-buffers.
protected int	SUB_BUFFER_MASK The bitmask used to break an index into a main index and a sub index.
protected int	SUB_BUFFER_SIZE The size of the sub-buffers.
protected int	writePtr The current location of the write pointer.

Constructor Summary

ByteArrayBuffer()
Constructs a new ByteArrayBuffer using default settings (64KB sub-buffers)

ByteArrayBuffer(int mainBufferSize, int subBufferLog)
Constructs a new ByteArrayBuffer with the specified dimensions.

Method Summary

void	clean() Nulls all pointers to aid with garbage collection.
void	close() Inherited from OutputStream, but does nothing.
void	fillZeroes() Fills all allocated buffers with 0's.
void	flush() Inherited from OutputStream; does nothing.
ByteArrayBuffer.ByteArrayBufferInputStream	getInputStream() Returns a ByteArrayBufferInputStream that can be used to read directly from the internal buffers of this object.
ByteArrayBuffer.ByteArrayBufferInputStream	getInputStream(boolean _sharedPointer) Returns a ByteArrayBufferInputStream that can be used to read directly from the internal buffers of this object.
int	getWritePtr() Gets the current value of the write pointer
int	length() Returns the current number of bytes used in the buffer.
int	seek(int newWritePtr) Changes the write pointer.
void	setLength(int newLength) Adjusts the number of bytes used in the buffer.
void	write(byte[] b) Writes the byte array b to the buffers.
void	write(byte[] b, int offset, int len) Writes len bytes from a byte array starting at b[offset].
void	write(int b) Writes a single byte to the buffers.

Methods inherited from class java.lang.Object

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

Field Detail

SUB_BUFFER_LOG

protected int SUB_BUFFER_LOG

The base 2 logarithm of the size of the sub-buffers.

SUB_BUFFER_SIZE

protected int SUB_BUFFER_SIZE

The size of the sub-buffers.

SUB_BUFFER_MASK

protected int SUB_BUFFER_MASK

The bitmask used to break an index into a main index and a sub index.

MAIN_BUFFER_SIZE

protected int MAIN_BUFFER_SIZE

The size of the main buffer.

mainBuffer

protected byte[][] mainBuffer

The main buffer.

bytesUsed

protected int bytesUsed

The number of bytes currently used.

writePtr

protected int writePtr

The current location of the write pointer.

mainBuffersAllocated

protected int mainBuffersAllocated

The number of buffers allocated in the main buffer.

Constructor Detail

ByteArrayBuffer

public ByteArrayBuffer()

Constructs a new ByteArrayBuffer using default settings (64KB sub-buffers)

ByteArrayBuffer

public ByteArrayBuffer(int mainBufferSize,
                       int subBufferLog)

Constructs a new ByteArrayBuffer with the specified dimensions.

Parameters:

mainBufferSize - The size of the main buffer. The main buffer simply holds sub-buffers, and will automatically grow as needed.

subBufferLog - The base 2 logarithm of the size of the sub-buffer. Sub-buffers are allocated at their full size as needed.

Method Detail

close

public void close()

Inherited from OutputStream, but does nothing.

Specified by:

close in interface java.io.Closeable

Overrides:

close in class java.io.OutputStream

clean

public void clean()

Nulls all pointers to aid with garbage collection.

flush

public void flush()

Inherited from OutputStream; does nothing.

Specified by:

flush in interface java.io.Flushable

Overrides:

flush in class java.io.OutputStream

write

public void write(byte[] b)

Writes the byte array b to the buffers.

Overrides:

write in class java.io.OutputStream

write

public void write(byte[] b,
                  int offset,
                  int len)

Writes len bytes from a byte array starting at b[offset].

Overrides:

write in class java.io.OutputStream

write

public void write(int b)

Writes a single byte to the buffers.

Specified by:

write in class java.io.OutputStream

length

public int length()

Returns the current number of bytes used in the buffer.

setLength

public void setLength(int newLength)

Adjusts the number of bytes used in the buffer. If the length is increasing, all new bytes are initialized to 0.

seek

public int seek(int newWritePtr)

Changes the write pointer.

getWritePtr

public int getWritePtr()

Gets the current value of the write pointer

fillZeroes

public void fillZeroes()

Fills all allocated buffers with 0's.

getInputStream

public ByteArrayBuffer.ByteArrayBufferInputStream getInputStream()

Returns a ByteArrayBufferInputStream that can be used to read directly from the internal buffers of this object. The returned stream will have its own read pointer independent of the write pointer.

getInputStream

public ByteArrayBuffer.ByteArrayBufferInputStream getInputStream(boolean _sharedPointer)

Returns a ByteArrayBufferInputStream that can be used to read directly from the internal buffers of this object. The returned stream can specify an independent or shared read pointer. If it is shared, reads affect the write pointer and writes affect the read pointer.

Parameters:

_sharedPointer - Specifies whether the read pointer should be shared with the write pointer.