libjava/java/util/zip/DeflaterOutputStream.java

   1 /* DeflaterOutputStream.java - Output filter for compressing.
   2    Copyright (C) 1999, 2000 Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19 02111-1307 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38 package java.util.zip;
  39
  40 import java.io.FilterOutputStream;
  41 import java.io.OutputStream;
  42 import java.io.IOException;
  43
  44 /* Written using on-line Java Platform 1.2 API Specification
  45  * and JCL book.
  46  * Believed complete and correct.
  47  */
  48
  49 /**
  50  * This is a special FilterOutputStream deflating the bytes that are
  51  * written through it.  It uses the Deflater for deflating.
  52  *
  53  * A special thing to be noted is that flush() doesn't flush
  54  * everything in Sun's JDK, but it does so in jazzlib. This is because
  55  * Sun's Deflater doesn't have a way to flush() everything, without
  56  * finishing the stream.
  57  *
  58  * @author Tom Tromey, Jochen Hoenicke
  59  * @date Jan 11, 2001
  60  */
  61 public class DeflaterOutputStream extends FilterOutputStream
  62 {
  63   public void close () throws IOException
  64   {
  65     finish ();
  66     out.close();
  67   }
  68
  69   /**
  70    * Deflates everything in the def's input buffers.  This will call
  71    * <code>def.deflate()</code> until all bytes from the input buffers
  72    * are processed.
  73    */
  74   protected void deflate () throws IOException
  75   {
  76     do
  77       {
  78         int len = def.deflate(buf, 0, buf.length);
  79         if (len > 0)
  80           out.write(buf, 0, len);
  81        }
  82     while (! def.needsInput());
  83   }
  84
  85   /**
  86    * Creates a new DeflaterOutputStream with a default Deflater and
  87    * default buffer size.
  88    * @param out the output stream where deflated output should be written.
  89    */
  90   public DeflaterOutputStream (OutputStream out)
  91   {
  92     this (out, new Deflater (), 512);
  93   }
  94
  95   /**
  96    * Creates a new DeflaterOutputStream with the given Deflater and
  97    * default buffer size.
  98    * @param out the output stream where deflated output should be written.
  99    * @param defl the underlying deflater.
 100    */
 101   public DeflaterOutputStream (OutputStream out, Deflater defl)
 102   {
 103     this (out, defl, 512);
 104   }
 105
 106   /**
 107    * Creates a new DeflaterOutputStream with the given Deflater and
 108    * buffer size.
 109    * @param out the output stream where deflated output should be written.
 110    * @param defl the underlying deflater.
 111    * @param bufsize the buffer size.
 112    * @exception IllegalArgumentException if bufsize isn't positive.
 113    */
 114   public DeflaterOutputStream(OutputStream out, Deflater defl, int bufsize)
 115   {
 116     super (out);
 117     if (bufsize <= 0)
 118       throw new IllegalArgumentException("bufsize <= 0");
 119     buf = new byte[bufsize];
 120     def = defl;
 121   }
 122
 123   /**
 124    * Finishes the stream by calling finish() on the deflater.  This
 125    * was the only way to ensure that all bytes are flushed in Sun's
 126    * JDK.
 127    */
 128   public void finish () throws IOException
 129   {
 130     inbufWrite();
 131     def.finish();
 132     while (! def.finished ())
 133       {
 134         int len = def.deflate(buf, 0, buf.length);
 135         if (len > 0)
 136           out.write(buf, 0, len);
 137       }
 138   }
 139
 140   public void write (int bval) throws IOException
 141   {
 142     if (inbuf == null)
 143       inbuf = new byte[128];
 144     else if (inbufLength == inbuf.length)
 145       inbufWrite ();
 146     inbuf[inbufLength++] = (byte) bval;
 147   }
 148
 149   public void write (byte[] buf, int off, int len) throws IOException
 150   {
 151     inbufWrite ();
 152     def.setInput (buf, off, len);
 153     deflate ();
 154   }
 155
 156   private void inbufWrite () throws IOException
 157   {
 158     if (inbufLength > 0)
 159       {
 160         int size = inbufLength;
 161         inbufLength = 0;
 162         write (inbuf, 0, size);
 163       }
 164   }
 165
 166   // Used, if needed, for write(int).
 167   private byte[] inbuf;
 168   // Used length of inbuf.
 169   private int inbufLength;
 170
 171   // The retrieval buffer.
 172   protected byte[] buf;
 173
 174   // Deflater used to compress data.
 175   protected Deflater def;
 176 }