TarTool example source code file (TarInputStream.java)

This example TarTool source code file (TarInputStream.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - TarTool tags/keywords

entryfactory, file, inputstream, invalidheaderexception, invalidheaderexception, io, ioexception, ioexception, off, string, tarbuffer, tarentry, tarentry, tarinputstream, tarinputstream

The TarTool TarInputStream.java source code

/*
** Authored by Timothy Gerard Endres
** <mailto:time@gjt.org>  
** 
** This work has been placed into the public domain.
** You may use this work in any way and for any purpose you wish.
**
** THIS SOFTWARE IS PROVIDED AS-IS WITHOUT WARRANTY OF ANY KIND,
** NOT EVEN THE IMPLIED WARRANTY OF MERCHANTABILITY. THE AUTHOR
** OF THIS SOFTWARE, ASSUMES _NO_ RESPONSIBILITY FOR ANY
** CONSEQUENCE RESULTING FROM THE USE, MODIFICATION, OR
** REDISTRIBUTION OF THIS SOFTWARE. 
** 
*/

package com.ice.tar;

import java.io.*;
import javax.activation.*;


/**
 * The TarInputStream reads a UNIX tar archive as an InputStream.
 * methods are provided to position at each successive entry in
 * the archive, and the read each entry as a normal input stream
 * using read().
 *
 * @version $Revision: 1.8 $
 * @author Timothy Gerard Endres,
 *  <a href="mailto:time@gjt.org">time@trustice.com.
 * @see TarBuffer
 * @see TarHeader
 * @see TarEntry
 */


public
class		TarInputStream
extends		FilterInputStream
	{
	protected boolean			debug;
	protected boolean			hasHitEOF;

	protected int				entrySize;
	protected int				entryOffset;

	protected byte[]			oneBuf;
	protected byte[]			readBuf;

	protected TarBuffer			buffer;

	protected TarEntry			currEntry;

	protected EntryFactory		eFactory;


	public
	TarInputStream( InputStream is )
		{
		this( is, TarBuffer.DEFAULT_BLKSIZE, TarBuffer.DEFAULT_RCDSIZE );
		}

	public
	TarInputStream( InputStream is, int blockSize )
		{
		this( is, blockSize, TarBuffer.DEFAULT_RCDSIZE );
		}

	public
	TarInputStream( InputStream is, int blockSize, int recordSize )
		{
		super( is );

		this.buffer = new TarBuffer( is, blockSize, recordSize );

		this.readBuf = null;
		this.oneBuf = new byte[1];
		this.debug = false;
		this.hasHitEOF = false;
		this.eFactory = null;
		}

	/**
	 * Sets the debugging flag.
	 *
	 * @param debugF True to turn on debugging.
	 */
	public void
	setDebug( boolean debugF )
		{
		this.debug = debugF;
		}

	/**
	 * Sets the debugging flag.
	 *
	 * @param debugF True to turn on debugging.
	 */
	public void
	setEntryFactory( EntryFactory factory )
		{
		this.eFactory = factory;
		}

	/**
	 * Sets the debugging flag in this stream's TarBuffer.
	 *
	 * @param debugF True to turn on debugging.
	 */
	public void
	setBufferDebug( boolean debug )
		{
		this.buffer.setDebug( debug );
		}

	/**
	 * Closes this stream. Calls the TarBuffer's close() method.
	 */
	public void
	close()
		throws IOException
		{
		this.buffer.close();
		}

	/**
	 * Get the record size being used by this stream's TarBuffer.
	 *
	 * @return The TarBuffer record size.
	 */
	public int
	getRecordSize()
		{
		return this.buffer.getRecordSize();
		}

	/**
	 * Get the available data that can be read from the current
	 * entry in the archive. This does not indicate how much data
	 * is left in the entire archive, only in the current entry.
	 * This value is determined from the entry's size header field
	 * and the amount of data already read from the current entry.
	 * 
	 *
	 * @return The number of available bytes for the current entry.
	 */
	public int
	available()
		throws IOException
		{
		return this.entrySize - this.entryOffset;
		}

	/**
	 * Skip bytes in the input buffer. This skips bytes in the
	 * current entry's data, not the entire archive, and will
	 * stop at the end of the current entry's data if the number
	 * to skip extends beyond that point.
	 *
	 * @param numToSkip The number of bytes to skip.
	 */
	public void
	skip( int numToSkip )
		throws IOException
		{
		// REVIEW
		// This is horribly inefficient, but it ensures that we
		// properly skip over bytes via the TarBuffer...
		//

		byte[] skipBuf = new byte[ 8 * 1024 ];

		for ( int num = numToSkip ; num > 0 ; )
			{
			int numRead =
				this.read( skipBuf, 0,
					( num > skipBuf.length ? skipBuf.length : num ) );

			if ( numRead == -1 )
				break;

			num -= numRead;
			}
		}

	/**
	 * Since we do not support marking just yet, we return false.
	 *
	 * @return False.
	 */
	public boolean
	markSupported()
		{
		return false;
		}

	/**
	 * Since we do not support marking just yet, we do nothing.
	 *
	 * @param markLimit The limit to mark.
	 */
	public void
	mark( int markLimit )
		{
		}

	/**
	 * Since we do not support marking just yet, we do nothing.
	 */
	public void
	reset()
		{
		}

	/**
	 * Get the next entry in this tar archive. This will skip
	 * over any remaining data in the current entry, if there
	 * is one, and place the input stream at the header of the
	 * next entry, and read the header and instantiate a new
	 * TarEntry from the header bytes and return that entry.
	 * If there are no more entries in the archive, null will
	 * be returned to indicate that the end of the archive has
	 * been reached.
	 *
	 * @return The next TarEntry in the archive, or null.
	 */
	public TarEntry
	getNextEntry()
		throws IOException
		{
		if ( this.hasHitEOF )
			return null;

		if ( this.currEntry != null )
			{
			int numToSkip = this.entrySize - this.entryOffset;

			if ( this.debug )
			System.err.println
				( "TarInputStream: SKIP currENTRY '"
				+ this.currEntry.getName() + "' SZ "
				+ this.entrySize + " OFF " + this.entryOffset
				+ "  skipping " + numToSkip + " bytes" );

			if ( numToSkip > 0 )
				{
				this.skip( numToSkip );
				}

			this.readBuf = null;
			}

		byte[] headerBuf = this.buffer.readRecord();

		if ( headerBuf == null )
			{
			if ( this.debug )
				{
				System.err.println( "READ NULL RECORD" );
				}

			this.hasHitEOF = true;
			}
		else if ( this.buffer.isEOFRecord( headerBuf ) )
			{
			if ( this.debug )
				{
				System.err.println( "READ EOF RECORD" );
				}

			this.hasHitEOF = true;
			}

		if ( this.hasHitEOF )
			{
			this.currEntry = null;
			}
		else
			{
			try {
				if ( this.eFactory == null )
					{
					this.currEntry = new TarEntry( headerBuf );
					}
				else
					{
					this.currEntry =
						this.eFactory.createEntry( headerBuf );
					}

				if ( ! ( headerBuf[257] == 'u' && headerBuf[258] == 's'
						&& headerBuf[259] == 't' && headerBuf[260] == 'a'
						&& headerBuf[261] == 'r' ) )
					{
					throw new InvalidHeaderException
						( "header magic is not 'ustar', but '"
							+ headerBuf[257] + headerBuf[258] + headerBuf[259]
							+ headerBuf[260] + headerBuf[261] + "', or (dec) "
							+ ((int)headerBuf[257]) + ", "
							+ ((int)headerBuf[258]) + ", "
							+ ((int)headerBuf[259]) + ", "
							+ ((int)headerBuf[260]) + ", "
							+ ((int)headerBuf[261]) );
					}

				if ( this.debug )
				System.err.println
					( "TarInputStream: SET CURRENTRY '"
						+ this.currEntry.getName()
						+ "' size = " + this.currEntry.getSize() );

				this.entryOffset = 0;
				// REVIEW How do we resolve this discrepancy?!
				this.entrySize = (int) this.currEntry.getSize();
				}
			catch ( InvalidHeaderException ex )
				{
				this.entrySize = 0;
				this.entryOffset = 0;
				this.currEntry = null;
				throw new InvalidHeaderException
					( "bad header in block "
						+ this.buffer.getCurrentBlockNum()
						+ " record "
						+ this.buffer.getCurrentRecordNum()
						+ ", " + ex.getMessage() );
				}
			}

		return this.currEntry;
		}

	/**
	 * Reads a byte from the current tar archive entry.
	 *
	 * This method simply calls read( byte[], int, int ).
	 *
	 * @return The byte read, or -1 at EOF.
	 */
	public int
	read()
		throws IOException
		{
		int num = this.read( this.oneBuf, 0, 1 );
		if ( num == -1 )
			return num;
		else
			return (int) this.oneBuf[0];
		}

	/**
	 * Reads bytes from the current tar archive entry.
	 *
	 * This method simply calls read( byte[], int, int ).
	 *
	 * @param buf The buffer into which to place bytes read.
	 * @return The number of bytes read, or -1 at EOF.
	 */
	public int
	read( byte[] buf )
		throws IOException
		{
		return this.read( buf, 0, buf.length );
		}

	/**
	 * Reads bytes from the current tar archive entry.
	 *
	 * This method is aware of the boundaries of the current
	 * entry in the archive and will deal with them as if they
	 * were this stream's start and EOF.
	 *
	 * @param buf The buffer into which to place bytes read.
	 * @param offset The offset at which to place bytes read.
	 * @param numToRead The number of bytes to read.
	 * @return The number of bytes read, or -1 at EOF.
	 */
	public int
	read( byte[] buf, int offset, int numToRead )
		throws IOException
		{
		int totalRead = 0;

		if ( this.entryOffset >= this.entrySize )
			return -1;

		if ( (numToRead + this.entryOffset) > this.entrySize )
			{
			numToRead = (this.entrySize - this.entryOffset);
			}

		if ( this.readBuf != null )
			{
			int sz = ( numToRead > this.readBuf.length )
						? this.readBuf.length : numToRead;

			System.arraycopy( this.readBuf, 0, buf, offset, sz );

			if ( sz >= this.readBuf.length )
				{
				this.readBuf = null;
				}
			else
				{
				int newLen = this.readBuf.length - sz;
				byte[] newBuf = new byte[ newLen ];
				System.arraycopy( this.readBuf, sz, newBuf, 0, newLen );
				this.readBuf = newBuf;
				}

			totalRead += sz;
			numToRead -= sz;
			offset += sz;
			}

		for ( ; numToRead > 0 ; )
			{
			byte[] rec = this.buffer.readRecord();
			if ( rec == null )
				{
				// Unexpected EOF!
				throw new IOException
					( "unexpected EOF with " + numToRead + " bytes unread" );
				}

			int sz = numToRead;
			int recLen = rec.length;

			if ( recLen > sz )
				{
				System.arraycopy( rec, 0, buf, offset, sz );
				this.readBuf = new byte[ recLen - sz ];
				System.arraycopy( rec, sz, this.readBuf, 0, recLen - sz );
				}
			else
				{
				sz = recLen;
				System.arraycopy( rec, 0, buf, offset, recLen );
				}

			totalRead += sz;
			numToRead -= sz;
			offset += sz;
			}

		this.entryOffset += totalRead;

		return totalRead;
		}

	/**
	 * Copies the contents of the current tar archive entry directly into
	 * an output stream.
	 *
	 * @param out The OutputStream into which to write the entry's data.
	 */
	public void
	copyEntryContents( OutputStream out )
		throws IOException
		{
		byte[] buf = new byte[ 32 * 1024 ];

		for ( ; ; )
			{
			int numRead = this.read( buf, 0, buf.length );
			if ( numRead == -1 )
				break;
			out.write( buf, 0, numRead );
			}
		}

	/**
	 * This interface is provided, with the method setEntryFactory(), to allow
	 * the programmer to have their own TarEntry subclass instantiated for the
	 * entries return from getNextEntry().
	 */

	public
	interface	EntryFactory
		{
		public TarEntry
			createEntry( String name );

		public TarEntry
			createEntry( File path )
				throws InvalidHeaderException;

		public TarEntry
			createEntry( byte[] headerBuf )
				throws InvalidHeaderException;
		}

	public
	class		EntryAdapter
	implements	EntryFactory
		{
		public TarEntry
		createEntry( String name )
			{
			return new TarEntry( name );
			}

		public TarEntry
		createEntry( File path )
			throws InvalidHeaderException
			{
			return new TarEntry( path );
			}

		public TarEntry
		createEntry( byte[] headerBuf )
			throws InvalidHeaderException
			{
			return new TarEntry( headerBuf );
			}
		}

	}