com.pervasive.datarush.io.compression.bzip2

Class BZip2CompressorInputStream

java.lang.Object

java.io.InputStream

org.apache.commons.compress.compressors.CompressorInputStream

com.pervasive.datarush.io.compression.bzip2.BZip2CompressorInputStream

All Implemented Interfaces:

BZip2Constants, Closeable, AutoCloseable

public class BZip2CompressorInputStream
extends org.apache.commons.compress.compressors.CompressorInputStream
implements BZip2Constants

An input stream that decompresses from the BZip2 format to be read as any other stream.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	BZip2CompressorInputStream.ReadMode

Field Summary

Fields inherited from interface com.pervasive.datarush.io.compression.bzip2.BZip2Constants

BASEBLOCKSIZE, G_SIZE, MAX_ALPHA_SIZE, MAX_CODE_LEN, MAX_SELECTORS, N_GROUPS, N_ITERS, NUM_OVERSHOOT_BYTES, RUNA, RUNB

Constructor Summary

Constructors

Constructor and Description
BZip2CompressorInputStream(InputStream in) Constructs a new BZip2CompressorInputStream which decompresses bytes read from the specified stream.
BZip2CompressorInputStream(InputStream in, BZip2CompressorInputStream.ReadMode readMode) Constructs a new BZip2CompressorInputStream which decompresses bytes read from the specified stream.

Method Summary

Modifier and Type	Method and Description
void	close()
long	getPosition() Get the current byte position with the raw input data stream.
boolean	initBlock() Initialize the next compression block.
static boolean	matches(byte[] signature, int length) Checks if the signature matches what is expected for a bzip2 file.
int	read()
int	read(byte[] dest, int offs, int len)
boolean	skipToBlock(long startOffset, long endOffset) Skip from the current raw input stream position to the start of the split boundary defined by the given start offset and end offset.

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

Constructor Detail

BZip2CompressorInputStream

public BZip2CompressorInputStream(InputStream in)
                           throws IOException

Constructs a new BZip2CompressorInputStream which decompresses bytes read from the specified stream. This doesn't suppprt decompressing concatenated .bz2 files.

Throws:

IOException - if the stream content is malformed or an I/O error occurs.

NullPointerException - if in == null

BZip2CompressorInputStream

public BZip2CompressorInputStream(InputStream in,
                                  BZip2CompressorInputStream.ReadMode readMode)
                           throws IOException

Constructs a new BZip2CompressorInputStream which decompresses bytes read from the specified stream.

Parameters:

in - the InputStream from which this object should be created

decompressConcatenated - if true, decompress until the end of the input; if false, stop after the first .bz2 stream and leave the input position to point to the next byte after the .bz2 stream

Throws:

IOException - if the stream content is malformed or an I/O error occurs.

NullPointerException - if in == null

Method Detail

read

public int read()
         throws IOException

Specified by:

read in class InputStream

Throws:

IOException

read

public int read(byte[] dest,
                int offs,
                int len)
         throws IOException

Overrides:

read in class InputStream

Throws:

IOException

initBlock

public boolean initBlock()
                  throws IOException

Initialize the next compression block. If at end of stream (the EOS marker) then determine if a concatenated bzip2 stream follows.

Returns:

true if at beginning of next block; false if EOS encountered

Throws:

IOException

close

public void close()
           throws IOException

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Overrides:

close in class InputStream

Throws:

IOException

matches

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

Checks if the signature matches what is expected for a bzip2 file.

Parameters:

signature - the bytes to check

length - the number of bytes to check

Returns:

true, if this stream is a bzip2 compressed stream, false otherwise

Since:

1.1

skipToBlock

public boolean skipToBlock(long startOffset,
                           long endOffset)
                    throws IOException

Skip from the current raw input stream position to the start of the split boundary defined by the given start offset and end offset. Once positioned at the start of the split, search for the magic marker that indicates the start of a compression block. Once found, cache the data read from the raw input stream into a byte buffer for processing.

Parameters:

startOffset - start byte offset of the data split

endOffset - end byte offset of the data split

Throws:

IOException - thrown if any I/O errors occur

getPosition

public long getPosition()

Get the current byte position with the raw input data stream. This position can be used to determine if the raw stream has crossed a split boundary or not.

Returns:

byte position with the raw data stream