org.apache.commons.compress.archivers.tar

Class TarBuffer

public class TarBuffer extends Object

The TarBuffer class implements the tar archive concept of a buffered input stream. This concept goes back to the days of blocked tape drives and special io devices. In the Java universe, the only real function that this class performs is to ensure that files have the correct "block" size, or other tars will complain.

You should never have a need to access this class directly. TarBuffers are created by Tar IO Streams.

Version: $Revision: 155439 $ $Date: 2006-08-28 08:10:02 +0200 (Mon, 28 Aug 2006) $

Author: Timothy Gerard Endres Peter Donald

Field Summary
static int	DEFAULT_BLOCKSIZE
static int	DEFAULT_RECORDSIZE
byte[]	m_blockBuffer
int	m_blockSize
int	m_currBlkIdx
int	m_currRecIdx
boolean	m_debug
InputStream	m_input
OutputStream	m_output
int	m_recordSize
int	m_recsPerBlock

Constructor Summary
	TarBuffer(InputStream input)
	TarBuffer(InputStream input, int blockSize)
	TarBuffer(InputStream input, int blockSize, int recordSize)
	TarBuffer(OutputStream output)
	TarBuffer(OutputStream output, int blockSize)
	TarBuffer(OutputStream output, int blockSize, int recordSize)

Method Summary
void	close() Close the TarBuffer.
protected void	debug(String message)
void	flushBlock() Flush the current data block if it has any data in it.
int	getBlockSize() Get the TAR Buffer's block size.
int	getCurrentBlockNum() Get the current block number, zero based.
int	getCurrentRecordNum() Get the current record number, within the current block, zero based.
int	getRecordSize() Get the TAR Buffer's record size.
void	initialize(int blockSize, int recordSize) Initialization common to all constructors.
boolean	isEOFRecord(byte[] record) Determine if an archive record indicate End of Archive.
boolean	readBlock()
byte[]	readRecord() Read a record from the input stream and return the data.
void	setDebug(boolean debug) Set the debugging flag for the buffer.
void	skipRecord() Skip over a record on the input stream.
void	writeBlock() Write a TarBuffer block to the archive.
void	writeRecord(byte[] record) Write an archive record to the archive.
void	writeRecord(byte[] buffer, int offset) Write an archive record to the archive, where the record may be inside of a larger array buffer.

Field Detail

DEFAULT_BLOCKSIZE

public static final int DEFAULT_BLOCKSIZE

DEFAULT_RECORDSIZE

public static final int DEFAULT_RECORDSIZE

m_blockBuffer

private byte[] m_blockBuffer

m_blockSize

private int m_blockSize

m_currBlkIdx

private int m_currBlkIdx

m_currRecIdx

private int m_currRecIdx

m_debug

private boolean m_debug

m_input

private InputStream m_input

m_output

private OutputStream m_output

m_recordSize

private int m_recordSize

m_recsPerBlock

private int m_recsPerBlock

Constructor Detail

TarBuffer

public TarBuffer(InputStream input)

TarBuffer

public TarBuffer(InputStream input, int blockSize)

TarBuffer

public TarBuffer(InputStream input, int blockSize, int recordSize)

TarBuffer

public TarBuffer(OutputStream output)

TarBuffer

public TarBuffer(OutputStream output, int blockSize)

TarBuffer

public TarBuffer(OutputStream output, int blockSize, int recordSize)

Method Detail

close

public void close()

Close the TarBuffer. If this is an output buffer, also flush the current block before closing.

debug

protected void debug(String message)

flushBlock

private void flushBlock()

Flush the current data block if it has any data in it.

getBlockSize

public int getBlockSize()

Get the TAR Buffer's block size. Blocks consist of multiple records.

Returns: The BlockSize value

getCurrentBlockNum

public int getCurrentBlockNum()

Get the current block number, zero based.

Returns: The current zero based block number.

getCurrentRecordNum

public int getCurrentRecordNum()

Get the current record number, within the current block, zero based. Thus, current offset = (currentBlockNum * recsPerBlk) + currentRecNum.

Returns: The current zero based record number.

getRecordSize

public int getRecordSize()

Get the TAR Buffer's record size.

Returns: The RecordSize value

initialize

private void initialize(int blockSize, int recordSize)

Initialization common to all constructors.

isEOFRecord

public boolean isEOFRecord(byte[] record)

Determine if an archive record indicate End of Archive. End of archive is indicated by a record that consists entirely of null bytes.

Parameters: record The record data to check.

Returns: The EOFRecord value

readBlock

private boolean readBlock()

Returns: false if End-Of-File, else true

readRecord

public byte[] readRecord()

Read a record from the input stream and return the data.

Returns: The record data.

Throws: IOException Description of Exception

setDebug

public void setDebug(boolean debug)

Set the debugging flag for the buffer.

Parameters: debug If true, print debugging output.

skipRecord

public void skipRecord()

Skip over a record on the input stream.

writeBlock

private void writeBlock()

Write a TarBuffer block to the archive.

Throws: IOException Description of Exception

writeRecord

public void writeRecord(byte[] record)

Write an archive record to the archive.

Parameters: record The record data to write to the archive.

writeRecord

public void writeRecord(byte[] buffer, int offset)

Write an archive record to the archive, where the record may be inside of a larger array buffer. The buffer must be "offset plus record size" long.

Parameters: buffer The buffer containing the record data to write. offset The offset of the record data within buf.