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Datei: Sprache: JAVA

Original von: Isabelle^©

/*
** Authored by Timothy Gerard Endres
** <mailto:[email protected]>  <http://www.trustice.com>
**
** 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 installer;

import java.io.*;

/**
* 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: 12504 $
* @author Timothy Gerard Endres,
*  <a href="mailto:[email protected]">[email protected]</a>.
* @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 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 );
   }
  }

}

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