Package org.apache.commons.compress.compressors.lz4

Class BlockLZ4CompressorOutputStream

java.lang.Object

java.io.OutputStream

org.apache.commons.compress.compressors.CompressorOutputStream

org.apache.commons.compress.compressors.lz4.BlockLZ4CompressorOutputStream

All Implemented Interfaces:

java.io.Closeable, java.io.Flushable, java.lang.AutoCloseable

public class BlockLZ4CompressorOutputStream
extends CompressorOutputStream

CompressorOutputStream for the LZ4 block format.

Since:

1.14

See Also:

LZ4 Block Format Description

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
(package private) static class	BlockLZ4CompressorOutputStream.Pair

Field Summary

Fields

Modifier and Type	Field	Description
private LZ77Compressor	compressor
private java.util.Deque<byte[]>	expandedBlocks
private boolean	finished
private static int	MIN_BACK_REFERENCE_LENGTH
private static int	MIN_OFFSET_OF_LAST_BACK_REFERENCE
private byte[]	oneByte
private java.io.OutputStream	os
private java.util.Deque<BlockLZ4CompressorOutputStream.Pair>	pairs

Constructor Summary

Constructors

Constructor	Description
BlockLZ4CompressorOutputStream(java.io.OutputStream os)	Creates a new LZ4 output stream.
BlockLZ4CompressorOutputStream(java.io.OutputStream os, Parameters params)	Creates a new LZ4 output stream.

Method Summary

Modifier and Type	Method	Description
private void	addBackReference(LZ77Compressor.BackReference block)
private void	addLiteralBlock(LZ77Compressor.LiteralBlock block)
private void	clearUnusedBlocks()
private void	clearUnusedBlocksAndPairs()
private void	clearUnusedPairs()
void	close()
static Parameters.Builder	createParameterBuilder()	Returns a builder correctly configured for the LZ4 algorithm.
private byte[]	expand(int offset, int length)
private void	expandFromList(byte[] expanded, int offset, int length)
void	finish()	Compresses all remaining data and writes it to the stream, doesn't close the underlying stream.
void	prefill(byte[] data, int off, int len)	Adds some initial data to fill the window with.
private void	recordBackReference(LZ77Compressor.BackReference block)
private void	recordLiteral(byte[] b)
private void	rewriteLastPairs()
void	write(byte[] data, int off, int len)
void	write(int b)
private BlockLZ4CompressorOutputStream.Pair	writeBlocksAndReturnUnfinishedPair(int length)
private void	writeFinalLiteralBlock()
private void	writeWritablePairs(int lengthOfBlocksAfterLastPair)

Methods inherited from class java.io.OutputStream

flush, nullOutputStream, write

Methods inherited from class java.lang.Object

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

Field Detail

MIN_BACK_REFERENCE_LENGTH

private static final int MIN_BACK_REFERENCE_LENGTH

See Also:

Constant Field Values

MIN_OFFSET_OF_LAST_BACK_REFERENCE

private static final int MIN_OFFSET_OF_LAST_BACK_REFERENCE

See Also:

Constant Field Values

compressor

private final LZ77Compressor compressor

os

private final java.io.OutputStream os

oneByte

private final byte[] oneByte

finished

private boolean finished

pairs

private final java.util.Deque<BlockLZ4CompressorOutputStream.Pair> pairs

expandedBlocks

private final java.util.Deque<byte[]> expandedBlocks

Constructor Detail

BlockLZ4CompressorOutputStream

public BlockLZ4CompressorOutputStream(java.io.OutputStream os)
                               throws java.io.IOException

Creates a new LZ4 output stream.

Parameters:

os - An OutputStream to read compressed data from

Throws:

java.io.IOException - if reading fails

BlockLZ4CompressorOutputStream

public BlockLZ4CompressorOutputStream(java.io.OutputStream os,
                                      Parameters params)
                               throws java.io.IOException

Creates a new LZ4 output stream.

Parameters:

os - An OutputStream to read compressed data from

params - The parameters to use for LZ77 compression.

Throws:

java.io.IOException - if reading fails

Method Detail

write

public void write(int b)
           throws java.io.IOException

Specified by:

write in class java.io.OutputStream

Throws:

java.io.IOException

write

public void write(byte[] data,
                  int off,
                  int len)
           throws java.io.IOException

Overrides:

write in class java.io.OutputStream

Throws:

java.io.IOException

close

public void close()
           throws java.io.IOException

Specified by:

close in interface java.lang.AutoCloseable

Specified by:

close in interface java.io.Closeable

Overrides:

close in class java.io.OutputStream

Throws:

java.io.IOException

finish

public void finish()
            throws java.io.IOException

Compresses all remaining data and writes it to the stream, doesn't close the underlying stream.

Throws:

java.io.IOException - if an error occurs

prefill

public void prefill(byte[] data,
                    int off,
                    int len)

Adds some initial data to fill the window with.

Parameters:

data - the data to fill the window with.

off - offset of real data into the array

len - amount of data

Throws:

java.lang.IllegalStateException - if the stream has already started to write data

See Also:

LZ77Compressor.prefill(byte[])

addLiteralBlock

private void addLiteralBlock(LZ77Compressor.LiteralBlock block)
                      throws java.io.IOException

Throws:

java.io.IOException

addBackReference

private void addBackReference(LZ77Compressor.BackReference block)
                       throws java.io.IOException

Throws:

java.io.IOException

writeBlocksAndReturnUnfinishedPair

private BlockLZ4CompressorOutputStream.Pair writeBlocksAndReturnUnfinishedPair(int length)
                                                                        throws java.io.IOException

Throws:

java.io.IOException

recordLiteral

private void recordLiteral(byte[] b)

clearUnusedBlocksAndPairs

private void clearUnusedBlocksAndPairs()

clearUnusedBlocks

private void clearUnusedBlocks()

recordBackReference

private void recordBackReference(LZ77Compressor.BackReference block)

expand

private byte[] expand(int offset,
                      int length)

expandFromList

private void expandFromList(byte[] expanded,
                            int offset,
                            int length)

clearUnusedPairs

private void clearUnusedPairs()

writeFinalLiteralBlock

private void writeFinalLiteralBlock()
                             throws java.io.IOException

Throws:

java.io.IOException

writeWritablePairs

private void writeWritablePairs(int lengthOfBlocksAfterLastPair)
                         throws java.io.IOException

Throws:

java.io.IOException

rewriteLastPairs

private void rewriteLastPairs()

createParameterBuilder

public static Parameters.Builder createParameterBuilder()

Returns a builder correctly configured for the LZ4 algorithm.

Returns:

a builder correctly configured for the LZ4 algorithm