Package org.apache.hadoop.io.compress.bzip2

Class Bzip2Decompressor

java.lang.Object

org.apache.hadoop.io.compress.bzip2.Bzip2Decompressor

All Implemented Interfaces:

Decompressor

public class Bzip2Decompressor
extends java.lang.Object
implements Decompressor

A Decompressor based on the popular bzip2 compression algorithm. http://www.bzip2.org/

Constructor Summary

Constructors

Constructor	Description
Bzip2Decompressor()
Bzip2Decompressor(boolean conserveMemory, int directBufferSize)	Creates a new decompressor.

Method Summary

Modifier and Type	Method	Description
int	decompress(byte[] b, int off, int len)	Fills specified buffer with uncompressed data.
void	end()	Closes the decompressor and discards any unprocessed input.
boolean	finished()	Returns true if the end of the decompressed data output stream has been reached.
long	getBytesRead()	Returns the total number of compressed bytes input so far.
long	getBytesWritten()	Returns the total number of uncompressed bytes output so far.
int	getRemaining()	Returns the number of bytes remaining in the input buffers; normally called when finished() is true to determine amount of post-gzip-stream data.
boolean	needsDictionary()	Returns true if a preset dictionary is needed for decompression.
boolean	needsInput()	Returns true if the input data buffer is empty and Decompressor.setInput(byte[], int, int) should be called to provide more input.
void	reset()	Resets everything including the input buffers (user and direct).
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, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Bzip2Decompressor

public Bzip2Decompressor(boolean conserveMemory,
                         int directBufferSize)

Creates a new decompressor.

Parameters:

conserveMemory - conserveMemory.

directBufferSize - directBufferSize.

Bzip2Decompressor

public Bzip2Decompressor()

Method Detail

setInput

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

Description copied from interface: Decompressor

Sets input data for decompression. This should be called if and only if Decompressor.needsInput() returns true indicating that more input data is required. (Both native and non-native versions of various Decompressors require that the data passed in via b[] remain unmodified until the caller is explicitly notified--via Decompressor.needsInput()--that the buffer may be safely modified. With this requirement, an extra buffer-copy can be avoided.)

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 Decompressor.setInput(byte[], int, int) should be called to provide more input.

Specified by:

needsInput in interface Decompressor

Returns:

true if the input data buffer is empty and Decompressor.setInput(byte[], int, int) 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 decompressed data output stream has been reached. Indicates a concatenated data stream when finished() returns true and Decompressor.getRemaining() returns a positive value. finished() will be reset with the Decompressor.reset() method.

Specified by:

finished in interface Decompressor

Returns:

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

decompress

public int decompress(byte[] b,
                      int off,
                      int len)
               throws java.io.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 Decompressor.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 uncompressed data

off - Start offset of the data

len - Size of the buffer

Returns:

The actual number of bytes of uncompressed data.

Throws:

java.io.IOException - raised on errors performing I/O.

getBytesWritten

public long getBytesWritten()

Returns the total number of uncompressed bytes output so far.

Returns:

the total (non-negative) number of uncompressed bytes output so far

getBytesRead

public long getBytesRead()

Returns the total number of compressed bytes input so far.

Returns:

the total (non-negative) number of compressed bytes input so far

getRemaining

public int getRemaining()

Returns the number of bytes remaining in the input buffers; normally called when finished() is true to determine amount of post-gzip-stream data.

Specified by:

getRemaining in interface Decompressor

Returns:

the total (non-negative) number of unprocessed bytes in input

reset

public void reset()

Resets everything including the input buffers (user and direct).

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