Package org.apache.hadoop.io.compress.snappy

Class SnappyDecompressor

java.lang.Object

org.apache.hadoop.io.compress.snappy.SnappyDecompressor

All Implemented Interfaces:

Decompressor

Direct Known Subclasses:

SnappyDecompressor.SnappyDirectDecompressor

public class SnappyDecompressor
extends Object
implements Decompressor

A Decompressor based on the snappy compression algorithm. http://code.google.com/p/snappy/

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	SnappyDecompressor.SnappyDirectDecompressor

Constructor Summary

Constructors

Constructor	Description
SnappyDecompressor()	Creates a new decompressor with the default buffer size.
SnappyDecompressor(int directBufferSize)	Creates a new compressor.

Method Summary

Modifier and Type	Method	Description
int	decompress(byte[] b, int off, int len)	Fills specified buffer with uncompressed data.
void	end()	Resets decompressor and input and output buffers so that a new set of input data can be processed.
boolean	finished()	Returns true if the end of the decompressed data output stream has been reached.
int	getRemaining()	Returns 0.
boolean	needsDictionary()	Returns false.
boolean	needsInput()	Returns true if the input data buffer is empty and setInput(byte[], int, int) should be called to provide more input.
void	reset()	Resets decompressor and input and output buffers so that a new set of input data can be processed.
void	setDictionary(byte[] b, int off, int len)	Does nothing.
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 Details

SnappyDecompressor

public SnappyDecompressor(int directBufferSize)

Creates a new compressor.

Parameters:

directBufferSize - size of the direct buffer to be used.

SnappyDecompressor

public SnappyDecompressor()

Creates a new decompressor with the default buffer size.

Method Details

setInput

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

Sets input data for decompression. This should be called if and only if 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 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)

Does nothing.

Specified by:

setDictionary in interface Decompressor

Parameters:

b - Dictionary data bytes

off - Start offset

len - Length

needsInput

public boolean needsInput()

Returns true if the input data buffer is empty and 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 setInput(byte[], int, int) should be called in order to provide more input.

needsDictionary

public boolean needsDictionary()

Returns false.

Specified by:

needsDictionary in interface Decompressor

Returns:

false.

finished

public boolean finished()

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

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 IOException

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 uncompressed data

off - Start offset of the data

len - Size of the buffer

Returns:

The actual number of bytes of compressed data.

Throws:

IOException - raised on errors performing I/O.

getRemaining

public int getRemaining()

Returns 0.

Specified by:

getRemaining in interface Decompressor

Returns:

0.

reset

public void reset()

Description copied from interface: Decompressor

Resets decompressor and input and output buffers so that a new set of input data can be processed. If Decompressor.finished()} returns true and Decompressor.getRemaining() returns a positive value, reset() is called before processing of the next data stream in the concatenated data stream. Decompressor.finished() will be reset and will return false when reset() is called.

Specified by:

reset in interface Decompressor

end

public void end()

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

Specified by:

end in interface Decompressor