org.apache.hadoop.io.compress.lzo
Class LzoDecompressor

java.lang.Object
  org.apache.hadoop.io.compress.lzo.LzoDecompressor

All Implemented Interfaces:

Decompressor

public class LzoDecompressor
extends Object
implements Decompressor

A Decompressor based on the lzo algorithm. http://www.oberhumer.com/opensource/lzo/

Nested Class Summary

static class

LzoDecompressor.CompressionStrategy

Constructor Summary

LzoDecompressor()
Creates a new lzo decompressor.

LzoDecompressor(LzoDecompressor.CompressionStrategy strategy, int directBufferSize)
Creates a new lzo decompressor.

Method Summary

int	decompress(byte[] b, int off, int len) Fills specified buffer with uncompressed data.
void	end() Closes the decompressor and discards any unprocessed input.
protected void	finalize()
boolean	finished() Returns true if the end of the compressed data output stream has been reached.
static boolean	isNativeLzoLoaded() Check if lzo decompressors are loaded and initialized.
boolean	needsDictionary() Returns true if a preset dictionary is needed for decompression.
boolean	needsInput() Returns true if the input data buffer is empty and #setInput() should be called to provide more input.
void	reset() Resets decompressor so that a new set of input data can be processed.
void	setDictionary(byte[] b, int off, int len) Sets preset dictionary for compression.
void	setInput(byte[] b, int off, int len) Sets input data for decompression.

Methods inherited from class java.lang.Object

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

Constructor Detail

LzoDecompressor

public LzoDecompressor(LzoDecompressor.CompressionStrategy strategy,
                       int directBufferSize)

Creates a new lzo decompressor.

Parameters:

strategy - lzo decompression algorithm

directBufferSize - size of the direct-buffer

LzoDecompressor

public LzoDecompressor()

Creates a new lzo decompressor.

Method Detail

isNativeLzoLoaded

public static boolean isNativeLzoLoaded()

Check if lzo decompressors are loaded and initialized.

Returns:

true if lzo decompressors are loaded & initialized, else false

setInput

public void setInput(byte[] b,
                     int off,
                     int len)

Description copied from interface: Decompressor

Sets input data for decompression. This should be called whenever #needsInput() returns true indicating that more input data is required.

Specified by:

setInput in interface Decompressor

Parameters:

b - Input data

off - Start offset

len - Length

setDictionary

public void setDictionary(byte[] b,
                          int off,
                          int len)

Description copied from interface: Decompressor

Sets preset dictionary for compression. A preset dictionary is used when the history buffer can be predetermined.

Specified by:

setDictionary in interface Decompressor

Parameters:

b - Dictionary data bytes

off - Start offset

len - Length

needsInput

public boolean needsInput()

Description copied from interface: Decompressor

Returns true if the input data buffer is empty and #setInput() should be called to provide more input.

Specified by:

needsInput in interface Decompressor

Returns:

true if the input data buffer is empty and #setInput() should be called in order to provide more input.

needsDictionary

public boolean needsDictionary()

Description copied from interface: Decompressor

Returns true if a preset dictionary is needed for decompression.

Specified by:

needsDictionary in interface Decompressor

Returns:

true if a preset dictionary is needed for decompression

finished

public boolean finished()

Description copied from interface: Decompressor

Returns true if the end of the compressed data output stream has been reached.

Specified by:

finished in interface Decompressor

Returns:

true if the end of the compressed data output stream has been reached.

decompress

public int decompress(byte[] b,
                      int off,
                      int len)
               throws IOException

Description copied from interface: Decompressor

Fills specified buffer with uncompressed data. Returns actual number of bytes of uncompressed data. A return value of 0 indicates that #needsInput() should be called in order to determine if more input data is required.

Specified by:

decompress in interface Decompressor

Parameters:

b - Buffer for the compressed data

off - Start offset of the data

len - Size of the buffer

Returns:

The actual number of bytes of compressed data.

Throws:

IOException

reset

public void reset()

Description copied from interface: Decompressor

Resets decompressor so that a new set of input data can be processed.

Specified by:

reset in interface Decompressor

end

public void end()

Description copied from interface: Decompressor

Closes the decompressor and discards any unprocessed input.

Specified by:

end in interface Decompressor

finalize

protected void finalize()

Overrides:

finalize in class Object