Source for java.util.zip.DeflaterOutputStream

   1: /* DeflaterOutputStream.java - Output filter for compressing.
   2:    Copyright (C) 1999, 2000, 2001, 2004, 2005 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., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 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: 
  39: package java.util.zip;
  40: 
  41: import java.io.FilterOutputStream;
  42: import java.io.IOException;
  43: import java.io.OutputStream;
  44: 
  45: /* Written using on-line Java Platform 1.2 API Specification
  46:  * and JCL book.
  47:  * Believed complete and correct.
  48:  */
  49: 
  50: /**
  51:  * This is a special FilterOutputStream deflating the bytes that are
  52:  * written through it.  It uses the Deflater for deflating.
  53:  *
  54:  * A special thing to be noted is that flush() doesn't flush
  55:  * everything in Sun's JDK, but it does so in jazzlib. This is because
  56:  * Sun's Deflater doesn't have a way to flush() everything, without
  57:  * finishing the stream.
  58:  *
  59:  * @author Tom Tromey, Jochen Hoenicke
  60:  * @date Jan 11, 2001 
  61:  */
  62: public class DeflaterOutputStream extends FilterOutputStream
  63: {
  64:   /** 
  65:    * This buffer is used temporarily to retrieve the bytes from the
  66:    * deflater and write them to the underlying output stream.  
  67:    */
  68:   protected byte[] buf;
  69: 
  70:   /** 
  71:    * The deflater which is used to deflate the stream.
  72:    */
  73:   protected Deflater def;
  74:   
  75:   /**
  76:    * Deflates everything in the def's input buffers.  This will call
  77:    * <code>def.deflate()</code> until all bytes from the input buffers
  78:    * are processed.
  79:    */
  80:   protected void deflate() throws IOException
  81:   {
  82:     while (! def.needsInput())
  83:       {
  84:     int len = def.deflate(buf, 0, buf.length);
  85: 
  86:     //    System.err.println("DOS deflated " + len + " out of " + buf.length);
  87:     if (len <= 0)
  88:       break;
  89:     out.write(buf, 0, len);
  90:       }
  91: 
  92:     if (! def.needsInput())
  93:       throw new InternalError("Can't deflate all input?");
  94:   }
  95: 
  96:   /** 
  97:    * Creates a new DeflaterOutputStream with a default Deflater and
  98:    * default buffer size.
  99:    * @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: }