sam.io
Class Mixer

java.lang.Object
  |
  +--sam.io.Mixer

Direct Known Subclasses:

HuffmanMixer, RandomMixer

public abstract class Mixer

extends java.lang.Object

Class for mixing streams with garbage bytes. Mixing consists of

 Mixer mixer = ...;
 OutputStream mixedOutput = mixer.new OutputStream(nativeOutput);
 ...  // Use 'mixedOutput' here
 mixedOutput.close();
 byte[] trace = mixer.getTrace();
 

then unmixing consists of

 byte[] trace = ...
 Mixer mixer = ...
 mixer.setTrace(trace);
 InputStream unmixedInput = mixer.new InputStream(mixedInput);
 ...  // Use 'unmixedInput' here
 

Nested Class Summary

class	Mixer.InputStream Inner-class for transparently unmixing an mixed stream
class	Mixer.OutputStream Inner-class for transparently mixing a stream The trace is stored back in the outer Mixer instance once the close() method is called

Field Summary

static sam.io.Mixer

DUMMY Dummy mixer implementation.

Constructor Summary

Mixer()

Method Summary

protected long	blockSize() Gets the block size of this mixer.
protected abstract long	getDataChunkLength(long blockSize) Sets the next data chunk length, in bytes.
byte[]	getTrace() Gets the current mixing trace since creation of the stream
long	nextDataChunkLength(long blockSize) Sets the next data chunk length, in bytes.
abstract void	readGarbageChunk(java.io.InputStream stream, long length) Reads garbage data from the stream.
void	setBlockSize(long blockSize) Sets the block size.
void	setTrace(byte[] trace) Sets the current mixing trace
void	setTracker(sam.io.Tracker tracker) Sets the tracker.
abstract void	writeGarbageChunk(java.io.OutputStream stream) Writes garbage data to the stream.

Methods inherited from class java.lang.Object

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

Field Detail

DUMMY

public static final sam.io.Mixer DUMMY

Dummy mixer implementation. This just does nothgin and serves as an example or for debugging purpose.

Constructor Detail

Mixer

public Mixer()

Method Detail

getDataChunkLength

protected abstract long getDataChunkLength(long blockSize)

Sets the next data chunk length, in bytes.

Parameters:

blockSize - the block size of the data stream, which might be zero to specify infinite block size A lazy implementation might just return blockSize

Returns:

desired data chunk length, or zero to specify unlimited data chunk

nextDataChunkLength

public long nextDataChunkLength(long blockSize)

Sets the next data chunk length, in bytes.

Parameters:

blockSize - the block size of the data stream, which might be zero to specify infinite block size A lazy implementation might just return blockSize

Returns:

desired data chunk length, or the maximum positive long to specify unlimited data chunk

writeGarbageChunk

public abstract void writeGarbageChunk(java.io.OutputStream stream)
                                throws java.io.IOException

Writes garbage data to the stream.

Parameters:

stream - the output to write onto Note that the number of bytes written will be kept back automatically

java.io.IOException

readGarbageChunk

public abstract void readGarbageChunk(java.io.InputStream stream,
                                      long length)
                               throws java.io.IOException

Reads garbage data from the stream.

Parameters:

stream - the input to write onto

length - the number of garbage bytes to read

java.io.IOException

blockSize

protected long blockSize()

Gets the block size of this mixer.

setBlockSize

public void setBlockSize(long blockSize)

Sets the block size.

setTracker

public void setTracker(sam.io.Tracker tracker)

Sets the tracker.

getTrace

public byte[] getTrace()

Gets the current mixing trace since creation of the stream

setTrace

public void setTrace(byte[] trace)

Sets the current mixing trace