001/* DeflaterOutputStream.java - Output filter for compressing.
002   Copyright (C) 1999, 2000, 2001, 2004, 2005 Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
011GNU Classpath is distributed in the hope that it will be useful, but
012WITHOUT ANY WARRANTY; without even the implied warranty of
013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
016You should have received a copy of the GNU General Public License
017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038
039package java.util.zip;
040
041import java.io.FilterOutputStream;
042import java.io.IOException;
043import 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 * This is a special FilterOutputStream deflating the bytes that are
052 * written through it.  It uses the Deflater for deflating.
053 *
054 * A special thing to be noted is that flush() doesn't flush
055 * everything in Sun's JDK, but it does so in jazzlib. This is because
056 * Sun's Deflater doesn't have a way to flush() everything, without
057 * finishing the stream.
058 *
059 * @author Tom Tromey, Jochen Hoenicke
060 * @date Jan 11, 2001
061 */
062public class DeflaterOutputStream extends FilterOutputStream
063{
064  /**
065   * This buffer is used temporarily to retrieve the bytes from the
066   * deflater and write them to the underlying output stream.
067   */
068  protected byte[] buf;
069
070  /**
071   * The deflater which is used to deflate the stream.
072   */
073  protected Deflater def;
074
075  /**
076   * Deflates everything in the def's input buffers.  This will call
077   * <code>def.deflate()</code> until all bytes from the input buffers
078   * are processed.
079   */
080  protected void deflate() throws IOException
081  {
082    while (! def.needsInput())
083      {
084        int len = def.deflate(buf, 0, buf.length);
085
086        //      System.err.println("DOS deflated " + len + " out of " + buf.length);
087        if (len <= 0)
088          break;
089        out.write(buf, 0, len);
090      }
091
092    if (! def.needsInput())
093      throw new InternalError("Can't deflate all input?");
094  }
095
096  /**
097   * Creates a new DeflaterOutputStream with a default Deflater and
098   * default buffer size.
099   * @param out the output stream where deflated output should be written.
100   */
101  public DeflaterOutputStream(OutputStream out)
102  {
103    this(out, new Deflater(), 4096);
104  }
105
106  /**
107   * Creates a new DeflaterOutputStream with the given Deflater and
108   * default buffer size.
109   * @param out the output stream where deflated output should be written.
110   * @param defl the underlying deflater.
111   */
112  public DeflaterOutputStream(OutputStream out, Deflater defl)
113  {
114    this(out, defl, 4096);
115  }
116
117  /**
118   * Creates a new DeflaterOutputStream with the given Deflater and
119   * buffer size.
120   * @param out the output stream where deflated output should be written.
121   * @param defl the underlying deflater.
122   * @param bufsize the buffer size.
123   * @exception IllegalArgumentException if bufsize isn't positive.
124   */
125  public DeflaterOutputStream(OutputStream out, Deflater defl, int bufsize)
126  {
127    super(out);
128    if (bufsize <= 0)
129      throw new IllegalArgumentException("bufsize <= 0");
130    buf = new byte[bufsize];
131    def = defl;
132  }
133
134  /**
135   * Flushes the stream by calling flush() on the deflater and then
136   * on the underlying stream.  This ensures that all bytes are
137   * flushed.  This function doesn't work in Sun's JDK, but only in
138   * jazzlib.
139   */
140  public void flush() throws IOException
141  {
142    def.flush();
143    deflate();
144    out.flush();
145  }
146
147  /**
148   * Finishes the stream by calling finish() on the deflater.  This
149   * was the only way to ensure that all bytes are flushed in Sun's
150   * JDK.
151   */
152  public void finish() throws IOException
153  {
154    def.finish();
155    while (! def.finished())
156      {
157        int len = def.deflate(buf, 0, buf.length);
158        if (len <= 0)
159          break;
160        out.write(buf, 0, len);
161      }
162    if (! def.finished())
163      throw new InternalError("Can't deflate all input?");
164    out.flush();
165  }
166
167  /**
168   * Calls finish() and closes the stream.
169   */
170  public void close() throws IOException
171  {
172    finish();
173    out.close();
174  }
175
176  /**
177   * Writes a single byte to the compressed output stream.
178   * @param bval the byte value.
179   */
180  public void write(int bval) throws IOException
181  {
182    byte[] b = new byte[1];
183    b[0] = (byte) bval;
184    write(b, 0, 1);
185  }
186
187  /**
188   * Writes a len bytes from an array to the compressed stream.
189   * @param buf the byte array.
190   * @param off the offset into the byte array where to start.
191   * @param len the number of bytes to write.
192   */
193  public void write(byte[] buf, int off, int len) throws IOException
194  {
195    def.setInput(buf, off, len);
196    deflate();
197  }
198}