001    /* CheckedOutputStream.java - Compute checksum of data being written.
002       Copyright (C) 1999, 2000 Free Software Foundation, Inc.
003    
004    This file is part of GNU Classpath.
005    
006    GNU Classpath is free software; you can redistribute it and/or modify
007    it under the terms of the GNU General Public License as published by
008    the Free Software Foundation; either version 2, or (at your option)
009    any later version.
010    
011    GNU Classpath is distributed in the hope that it will be useful, but
012    WITHOUT ANY WARRANTY; without even the implied warranty of
013    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014    General Public License for more details.
015    
016    You should have received a copy of the GNU General Public License
017    along with GNU Classpath; see the file COPYING.  If not, write to the
018    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019    02110-1301 USA.
020    
021    Linking this library statically or dynamically with other modules is
022    making a combined work based on this library.  Thus, the terms and
023    conditions of the GNU General Public License cover the whole
024    combination.
025    
026    As a special exception, the copyright holders of this library give you
027    permission to link this library with independent modules to produce an
028    executable, regardless of the license terms of these independent
029    modules, and to copy and distribute the resulting executable under
030    terms of your choice, provided that you also meet, for each linked
031    independent module, the terms and conditions of the license of that
032    module.  An independent module is a module which is not derived from
033    or based on this library.  If you modify this library, you may extend
034    this exception to your version of the library, but you are not
035    obligated to do so.  If you do not wish to do so, delete this
036    exception statement from your version. */
037    
038    
039    package java.util.zip;
040    
041    import java.io.FilterOutputStream;
042    import java.io.IOException;
043    import java.io.OutputStream;
044    
045    /* Written using on-line Java Platform 1.2 API Specification
046     * and JCL book.
047     * Believed complete and correct.
048     */
049    
050    /**
051     * OutputStream that computes a checksum of data being written using a
052     * supplied Checksum object.
053     *
054     * @see Checksum
055     *
056     * @author Tom Tromey
057     * @date May 17, 1999
058     */
059    public class CheckedOutputStream extends FilterOutputStream
060    {
061      /**
062       * Creates a new CheckInputStream on top of the supplied OutputStream
063       * using the supplied Checksum.
064       */
065      public CheckedOutputStream (OutputStream out, Checksum cksum)
066      {
067        super (out);
068        this.sum = cksum;
069      }
070    
071      /**
072       * Returns the Checksum object used. To get the data checksum computed so
073       * far call <code>getChecksum.getValue()</code>.
074       */
075      public Checksum getChecksum ()
076      {
077        return sum;
078      }
079    
080      /**
081       * Writes one byte to the OutputStream and updates the Checksum.
082       */
083      public void write (int bval) throws IOException
084      {
085        out.write(bval);
086        sum.update(bval);
087      }
088    
089      /**
090       * Writes the byte array to the OutputStream and updates the Checksum.
091       */
092      public void write (byte[] buf, int off, int len) throws IOException
093      {
094        out.write(buf, off, len);
095        sum.update(buf, off, len);
096      }
097    
098      /** The checksum object. */
099      private Checksum sum;
100    }