com.ning.compress.lzf.impl

Class UnsafeChunkDecoder

java.lang.Object

com.ning.compress.lzf.ChunkDecoder

com.ning.compress.lzf.impl.UnsafeChunkDecoder

public class UnsafeChunkDecoder
extends ChunkDecoder

Highly optimized ChunkDecoder implementation that uses Sun JDK's Unsafe class (which may be included by other JDK's as well; IBM's apparently does).

Credits for the idea go to Dain Sundstrom, who kindly suggested this use, and is all-around great source for optimization tips and tricks. Big thanks also to LZ4-java developers, whose stellar performance made me go back and see what more I can do to optimize this code!

Field Summary

Fields inherited from class com.ning.compress.lzf.ChunkDecoder

BYTE_NULL, HEADER_BYTES

Constructor Summary

Constructors

Constructor and Description
UnsafeChunkDecoder()

Method Summary

Modifier and Type	Method and Description
void	decodeChunk(byte[] in, int inPos, byte[] out, int outPos, int outEnd) Main decode method for individual chunks.
int	decodeChunk(InputStream is, byte[] inputBuffer, byte[] outputBuffer) Main decode from a stream.
int	skipOrDecodeChunk(InputStream is, byte[] inputBuffer, byte[] outputBuffer, long maxToSkip)

Methods inherited from class com.ning.compress.lzf.ChunkDecoder

_reportArrayOverflow, _reportCorruptHeader, calculateUncompressedSize, decode, decode, decode, decode, readFully, readHeader, skipFully, uint16

Methods inherited from class java.lang.Object

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

Constructor Detail

UnsafeChunkDecoder

public UnsafeChunkDecoder()

Method Detail

decodeChunk

public final int decodeChunk(InputStream is,
                             byte[] inputBuffer,
                             byte[] outputBuffer)
                      throws IOException

Description copied from class: ChunkDecoder

Main decode from a stream. Decompressed bytes are placed in the outputBuffer, inputBuffer is a "scratch-area".

Specified by:

decodeChunk in class ChunkDecoder

Parameters:

is - An input stream of LZF compressed bytes

inputBuffer - A byte array used as a scratch area.

outputBuffer - A byte array in which the result is returned

Returns:

The number of bytes placed in the outputBuffer.

Throws:

IOException

decodeChunk

public final void decodeChunk(byte[] in,
                              int inPos,
                              byte[] out,
                              int outPos,
                              int outEnd)
                       throws LZFException

Description copied from class: ChunkDecoder

Main decode method for individual chunks.

Specified by:

decodeChunk in class ChunkDecoder

Throws:

LZFException

skipOrDecodeChunk

public int skipOrDecodeChunk(InputStream is,
                             byte[] inputBuffer,
                             byte[] outputBuffer,
                             long maxToSkip)
                      throws IOException

Specified by:

skipOrDecodeChunk in class ChunkDecoder

Returns:

If positive number, number of bytes skipped; if -1, end-of-stream was reached; otherwise, amount of content decoded (using formula of returnValue = -(decodedAmount + 2))

Throws:

IOException