Package org.apache.tools.tar

Class TarBuffer

java.lang.Object

org.apache.tools.tar.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.

Field Summary

Fields

Modifier and Type	Field	Description
static final int	DEFAULT_BLKSIZE	Default block size
static final int	DEFAULT_RCDSIZE	Default record size

Constructor Summary

Constructors

Constructor	Description
TarBuffer(InputStream inStream)	Constructor for a TarBuffer on an input stream.
TarBuffer(InputStream inStream, int blockSize)	Constructor for a TarBuffer on an input stream.
TarBuffer(InputStream inStream, int blockSize, int recordSize)	Constructor for a TarBuffer on an input stream.
TarBuffer(OutputStream outStream)	Constructor for a TarBuffer on an output stream.
TarBuffer(OutputStream outStream, int blockSize)	Constructor for a TarBuffer on an output stream.
TarBuffer(OutputStream outStream, int blockSize, int recordSize)	Constructor for a TarBuffer on an output stream.

Method Summary

Modifier and Type	Method	Description
void	close()	Close the TarBuffer.
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.
boolean	isEOFRecord(byte[] record)	Determine if an archive record indicate End of Archive.
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	writeRecord(byte[] record)	Write an archive record to the archive.
void	writeRecord(byte[] buf, int offset)	Write an archive record to the archive, where the record may be inside of a larger array buffer.

Methods inherited from class java.lang.Object

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

Field Details

DEFAULT_RCDSIZE

public static final int DEFAULT_RCDSIZE

Default record size

See Also:

• Constant Field Values

DEFAULT_BLKSIZE

public static final int DEFAULT_BLKSIZE

Default block size

See Also:

• Constant Field Values

Constructor Details

TarBuffer

public TarBuffer(InputStream inStream)

Constructor for a TarBuffer on an input stream.

Parameters:

inStream - the input stream to use

TarBuffer

public TarBuffer(InputStream inStream,
 int blockSize)

Constructor for a TarBuffer on an input stream.

Parameters:

inStream - the input stream to use

blockSize - the block size to use

TarBuffer

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

Constructor for a TarBuffer on an input stream.

Parameters:

inStream - the input stream to use

blockSize - the block size to use

recordSize - the record size to use

TarBuffer

public TarBuffer(OutputStream outStream)

Constructor for a TarBuffer on an output stream.

Parameters:

outStream - the output stream to use

TarBuffer

public TarBuffer(OutputStream outStream,
 int blockSize)

Constructor for a TarBuffer on an output stream.

Parameters:

outStream - the output stream to use

blockSize - the block size to use

TarBuffer

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

Constructor for a TarBuffer on an output stream.

Parameters:

outStream - the output stream to use

blockSize - the block size to use

recordSize - the record size to use

Method Details

getBlockSize

public int getBlockSize()

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

Returns:

the block size

getRecordSize

public int getRecordSize()

Get the TAR Buffer's record size.

Returns:

the record size

setDebug

public void setDebug(boolean debug)

Set the debugging flag for the buffer.

Parameters:

debug - If true, print debugging output.

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:

true if the record data is an End of Archive

skipRecord

public void skipRecord()
                throws IOException

Skip over a record on the input stream.

Throws:

IOException - on error

readRecord

public byte[] readRecord()
                  throws IOException

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

Returns:

The record data.

Throws:

IOException - on error

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.

writeRecord

public void writeRecord(byte[] record)
                 throws IOException

Write an archive record to the archive.

Parameters:

record - The record data to write to the archive.

Throws:

IOException - on error

writeRecord

public void writeRecord(byte[] buf,
 int offset)
                 throws IOException

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:

buf - The buffer containing the record data to write.

offset - The offset of the record data within buf.

Throws:

IOException - on error

close

public void close()
           throws IOException

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

Throws:

IOException - on error