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

Class BlockLZ4CompressorOutputStream

java.lang.Object

java.io.OutputStream

java.io.FilterOutputStream

org.apache.commons.compress.CompressFilterOutputStream<OutputStream>

org.apache.commons.compress.compressors.CompressorOutputStream<OutputStream>

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

All Implemented Interfaces:

Closeable, Flushable, AutoCloseable

public class BlockLZ4CompressorOutputStream
extends CompressorOutputStream<OutputStream>

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 final class	BlockLZ4CompressorOutputStream.Pair

Field Summary

Fields

Modifier and Type	Field	Description
private final LZ77Compressor	compressor
private final Deque<byte[]>	expandedBlocks
private static final int	MIN_BACK_REFERENCE_LENGTH
private static final int	MIN_OFFSET_OF_LAST_BACK_REFERENCE
private final byte[]	oneByte
private final Deque<BlockLZ4CompressorOutputStream.Pair>	pairs

Fields inherited from class java.io.FilterOutputStream

out

Constructor Summary

Constructors

Constructor	Description
BlockLZ4CompressorOutputStream(OutputStream out)	Creates a new LZ4 output stream.
BlockLZ4CompressorOutputStream(OutputStream out, 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 org.apache.commons.compress.CompressFilterOutputStream

checkOpen, isClosed, isFinished, out, write, write, writeUsAscii, writeUsAsciiRaw, writeUtf8

Methods inherited from class java.io.FilterOutputStream

flush, write

Methods inherited from class java.lang.Object

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

Field Details

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

oneByte

private final byte[] oneByte

pairs

private final Deque<BlockLZ4CompressorOutputStream.Pair> pairs

expandedBlocks

private final Deque<byte[]> expandedBlocks

Constructor Details

BlockLZ4CompressorOutputStream

public BlockLZ4CompressorOutputStream(OutputStream out)

Creates a new LZ4 output stream.

Parameters:

out - An OutputStream to read compressed data from

BlockLZ4CompressorOutputStream

public BlockLZ4CompressorOutputStream(OutputStream out,
 Parameters params)

Creates a new LZ4 output stream.

Parameters:

out - An OutputStream to read compressed data from

params - The parameters to use for LZ77 compression.

Method Details

createParameterBuilder

public static Parameters.Builder createParameterBuilder()

Returns a builder correctly configured for the LZ4 algorithm.

Returns:

a builder correctly configured for the LZ4 algorithm

addBackReference

private void addBackReference(LZ77Compressor.BackReference block)
                       throws IOException

Throws:

IOException

addLiteralBlock

private void addLiteralBlock(LZ77Compressor.LiteralBlock block)
                      throws IOException

Throws:

IOException

clearUnusedBlocks

private void clearUnusedBlocks()

clearUnusedBlocksAndPairs

private void clearUnusedBlocksAndPairs()

clearUnusedPairs

private void clearUnusedPairs()

close

public void close()
           throws IOException

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Overrides:

close in class CompressFilterOutputStream<OutputStream>

Throws:

IOException

expand

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

expandFromList

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

finish

public void finish()
            throws IOException

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

Overrides:

finish in class CompressFilterOutputStream<OutputStream>

Throws:

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:

IllegalStateException - if the stream has already started to write data

See Also:

• LZ77Compressor.prefill(byte[])

recordBackReference

private void recordBackReference(LZ77Compressor.BackReference block)

recordLiteral

private void recordLiteral(byte[] b)

rewriteLastPairs

private void rewriteLastPairs()

write

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

Overrides:

write in class FilterOutputStream

Throws:

IOException

write

public void write(int b)
           throws IOException

Overrides:

write in class FilterOutputStream

Throws:

IOException

writeBlocksAndReturnUnfinishedPair

private BlockLZ4CompressorOutputStream.Pair writeBlocksAndReturnUnfinishedPair(int length)
                                                                        throws IOException

Throws:

IOException

writeFinalLiteralBlock

private void writeFinalLiteralBlock()
                             throws IOException

Throws:

IOException

writeWritablePairs

private void writeWritablePairs(int lengthOfBlocksAfterLastPair)
                         throws IOException

Throws:

IOException