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

Class FramedLZ4CompressorInputStream

java.lang.Object

java.io.InputStream

org.apache.commons.compress.compressors.CompressorInputStream

org.apache.commons.compress.compressors.lz4.FramedLZ4CompressorInputStream

All Implemented Interfaces:

Closeable, AutoCloseable, InputStreamStatistics

public class FramedLZ4CompressorInputStream
extends CompressorInputStream
implements InputStreamStatistics

CompressorInputStream for the LZ4 frame format.

Based on the "spec" in the version "1.5.1 (31/03/2015)"

Since:

1.14

See Also:

• LZ4 Frame Format Description

Field Summary

Fields

Modifier and Type	Field	Description
(package private) static final int	BLOCK_CHECKSUM_MASK
(package private) static final int	BLOCK_INDEPENDENCE_MASK
(package private) static final int	BLOCK_MAX_SIZE_MASK
private byte[]	blockDependencyBuffer
private final XXHash32	blockHash
(package private) static final int	CONTENT_CHECKSUM_MASK
(package private) static final int	CONTENT_SIZE_MASK
private final XXHash32	contentHash
private InputStream	currentBlock
private final boolean	decompressConcatenated
private boolean	endReached
private boolean	expectBlockChecksum
private boolean	expectBlockDependency
private boolean	expectContentChecksum
private boolean	expectContentSize
private final CountingInputStream	inputStream
private boolean	inUncompressed
(package private) static final byte[]	LZ4_SIGNATURE
private final byte[]	oneByte
private static final byte	SKIPPABLE_FRAME_PREFIX_BYTE_MASK
private static final byte[]	SKIPPABLE_FRAME_TRAILER
private final ByteUtils.ByteSupplier	supplier
(package private) static final int	SUPPORTED_VERSION
(package private) static final int	UNCOMPRESSED_FLAG_MASK
(package private) static final int	VERSION_MASK

Constructor Summary

Constructors

Constructor	Description
FramedLZ4CompressorInputStream(InputStream in)	Creates a new input stream that decompresses streams compressed using the LZ4 frame format and stops after decompressing the first frame.
FramedLZ4CompressorInputStream(InputStream in, boolean decompressConcatenated)	Creates a new input stream that decompresses streams compressed using the LZ4 frame format.

Method Summary

Modifier and Type	Method	Description
private void	appendToBlockDependencyBuffer(byte[] b, int off, int len)
void	close()
long	getCompressedCount()	Gets the amount of raw or compressed bytes read by the stream.
private void	init(boolean firstFrame)
private static boolean	isSkippableFrameSignature(byte[] b)
static boolean	matches(byte[] signature, int length)	Checks if the signature matches what is expected for a .lz4 file.
private void	maybeFinishCurrentBlock()
private void	nextBlock()
int	read()
int	read(byte[] b, int off, int len)
private void	readFrameDescriptor()
private int	readOnce(byte[] b, int off, int len)
private int	readOneByte()
private boolean	readSignature(boolean firstFrame)
private int	skipSkippableFrame(byte[] b)	Skips over the contents of a skippable frame as well as skippable frames following it.
private void	verifyChecksum(XXHash32 hash, String kind)
private void	verifyContentChecksum()

Methods inherited from class org.apache.commons.compress.compressors.CompressorInputStream

count, count, getBytesRead, getCount, getUncompressedCount, pushedBackBytes

Methods inherited from class java.io.InputStream

available, mark, markSupported, read, reset, skip

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.commons.compress.utils.InputStreamStatistics

getUncompressedCount

Field Details

LZ4_SIGNATURE

static final byte[] LZ4_SIGNATURE

SKIPPABLE_FRAME_TRAILER

private static final byte[] SKIPPABLE_FRAME_TRAILER

SKIPPABLE_FRAME_PREFIX_BYTE_MASK

private static final byte SKIPPABLE_FRAME_PREFIX_BYTE_MASK

See Also:

• Constant Field Values

VERSION_MASK

static final int VERSION_MASK

See Also:

• Constant Field Values

SUPPORTED_VERSION

static final int SUPPORTED_VERSION

See Also:

• Constant Field Values

BLOCK_INDEPENDENCE_MASK

static final int BLOCK_INDEPENDENCE_MASK

See Also:

• Constant Field Values

BLOCK_CHECKSUM_MASK

static final int BLOCK_CHECKSUM_MASK

See Also:

• Constant Field Values

CONTENT_SIZE_MASK

static final int CONTENT_SIZE_MASK

See Also:

• Constant Field Values

CONTENT_CHECKSUM_MASK

static final int CONTENT_CHECKSUM_MASK

See Also:

• Constant Field Values

BLOCK_MAX_SIZE_MASK

static final int BLOCK_MAX_SIZE_MASK

See Also:

• Constant Field Values

UNCOMPRESSED_FLAG_MASK

static final int UNCOMPRESSED_FLAG_MASK

See Also:

• Constant Field Values

oneByte

private final byte[] oneByte

supplier

private final ByteUtils.ByteSupplier supplier

inputStream

private final CountingInputStream inputStream

decompressConcatenated

private final boolean decompressConcatenated

expectBlockChecksum

private boolean expectBlockChecksum

expectBlockDependency

private boolean expectBlockDependency

expectContentSize

private boolean expectContentSize

expectContentChecksum

private boolean expectContentChecksum

currentBlock

private InputStream currentBlock

endReached

private boolean endReached

inUncompressed

private boolean inUncompressed

contentHash

private final XXHash32 contentHash

blockHash

private final XXHash32 blockHash

blockDependencyBuffer

private byte[] blockDependencyBuffer

Constructor Details

FramedLZ4CompressorInputStream

public FramedLZ4CompressorInputStream(InputStream in)
                               throws IOException

Creates a new input stream that decompresses streams compressed using the LZ4 frame format and stops after decompressing the first frame.

Parameters:

in - the InputStream from which to read the compressed data

Throws:

IOException - if reading fails

FramedLZ4CompressorInputStream

public FramedLZ4CompressorInputStream(InputStream in,
 boolean decompressConcatenated)
                               throws IOException

Creates a new input stream that decompresses streams compressed using the LZ4 frame format.

Parameters:

in - the InputStream from which to read the compressed data

decompressConcatenated - if true, decompress until the end of the input; if false, stop after the first LZ4 frame and leave the input position to point to the next byte after the frame stream

Throws:

IOException - if reading fails

Method Details

isSkippableFrameSignature

private static boolean isSkippableFrameSignature(byte[] b)

matches

public static boolean matches(byte[] signature,
 int length)

Checks if the signature matches what is expected for a .lz4 file.

.lz4 files start with a four byte signature.

Parameters:

signature - the bytes to check

length - the number of bytes to check

Returns:

true if this is a .sz stream, false otherwise

appendToBlockDependencyBuffer

private void appendToBlockDependencyBuffer(byte[] b,
 int off,
 int len)

close

public void close()
           throws IOException

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Overrides:

close in class InputStream

Throws:

IOException

getCompressedCount

public long getCompressedCount()

Description copied from interface: InputStreamStatistics

Gets the amount of raw or compressed bytes read by the stream.

Specified by:

getCompressedCount in interface InputStreamStatistics

Returns:

the amount of raw or compressed bytes read by the stream.

Since:

1.17

init

private void init(boolean firstFrame)
           throws IOException

Throws:

IOException

maybeFinishCurrentBlock

private void maybeFinishCurrentBlock()
                              throws IOException

Throws:

IOException

nextBlock

private void nextBlock()
                throws IOException

Throws:

IOException

read

public int read()
         throws IOException

Specified by:

read in class InputStream

Throws:

IOException

read

public int read(byte[] b,
 int off,
 int len)
         throws IOException

Overrides:

read in class InputStream

Throws:

IOException

readFrameDescriptor

private void readFrameDescriptor()
                          throws IOException

Throws:

IOException

readOnce

private int readOnce(byte[] b,
 int off,
 int len)
              throws IOException

Throws:

IOException

readOneByte

private int readOneByte()
                 throws IOException

Throws:

IOException

readSignature

private boolean readSignature(boolean firstFrame)
                       throws IOException

Throws:

IOException

skipSkippableFrame

private int skipSkippableFrame(byte[] b)
                        throws IOException

Skips over the contents of a skippable frame as well as skippable frames following it.

It then tries to read four more bytes which are supposed to hold an LZ4 signature and returns the number of bytes read while storing the bytes in the given array.

Throws:

IOException

verifyChecksum

private void verifyChecksum(XXHash32 hash,
 String kind)
                     throws IOException

Throws:

IOException

verifyContentChecksum

private void verifyContentChecksum()
                            throws IOException

Throws:

IOException