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:

    • DEFAULT_BLKSIZE

      public static final int DEFAULT_BLKSIZE
      Default block size
      See Also:

  • 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