Source for java.util.zip.DeflaterOutputStream

   1: /* DeflaterOutputStream.java - Output filter for compressing.
   2:    Copyright (C) 1999, 2000, 2001, 2004 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:     if (len > 0)
  86:       out.write(buf, 0, len);
  87:        }
  88:   }
  89: 
  90:   /** 
  91:    * Creates a new DeflaterOutputStream with a default Deflater and
  92:    * default buffer size.
  93:    * @param out the output stream where deflated output should be written.
  94:    */
  95:   public DeflaterOutputStream(OutputStream out)
  96:   {
  97:     this(out, new Deflater(), 512);
  98:   }
  99: 
 100:   /** 
 101:    * Creates a new DeflaterOutputStream with the given Deflater and
 102:    * default buffer size.
 103:    * @param out the output stream where deflated output should be written.
 104:    * @param defl the underlying deflater.
 105:    */
 106:   public DeflaterOutputStream(OutputStream out, Deflater defl)
 107:   {
 108:     this(out, defl, 512);
 109:   }
 110: 
 111:   /** 
 112:    * Creates a new DeflaterOutputStream with the given Deflater and
 113:    * buffer size.
 114:    * @param out the output stream where deflated output should be written.
 115:    * @param defl the underlying deflater.
 116:    * @param bufsize the buffer size.
 117:    * @exception IllegalArgumentException if bufsize isn't positive.
 118:    */
 119:   public DeflaterOutputStream(OutputStream out, Deflater defl, int bufsize)
 120:   {
 121:     super(out);
 122:     if (bufsize <= 0)
 123:       throw new IllegalArgumentException("bufsize <= 0");
 124:     buf = new byte[bufsize];
 125:     def = defl;
 126:   }
 127: 
 128:   /**
 129:    * Finishes the stream by calling finish() on the deflater.  This
 130:    * was the only way to ensure that all bytes are flushed in Sun's
 131:    * JDK.  
 132:    */
 133:   public void finish() throws IOException
 134:   {
 135:     inbufWrite();
 136:     def.finish();
 137:     while (! def.finished())
 138:       {
 139:     int len = def.deflate(buf, 0, buf.length);
 140:     if (len > 0)
 141:       out.write(buf, 0, len);
 142:       }
 143:   }
 144: 
 145:   /**
 146:    * Calls finish() and closes the stream. 
 147:    */
 148:   public void close() throws IOException
 149:   {
 150:     finish();
 151:     out.close();
 152:   }
 153: 
 154:   /**
 155:    * Writes a single byte to the compressed output stream.
 156:    * @param bval the byte value.
 157:    */
 158:   public void write(int bval) throws IOException
 159:   {
 160:     if (inbuf == null)
 161:       inbuf = new byte[128];
 162:     else if (inbufLength == inbuf.length)
 163:       inbufWrite();
 164:     inbuf[inbufLength++] = (byte) bval;
 165:   }
 166: 
 167:   /**
 168:    * Writes a len bytes from an array to the compressed stream.
 169:    * @param buf the byte array.
 170:    * @param off the offset into the byte array where to start.
 171:    * @param len the number of bytes to write.
 172:    */
 173:   public void write(byte[] buf, int off, int len) throws IOException
 174:   {
 175:     inbufWrite();
 176:     def.setInput(buf, off, len);
 177:     deflate();
 178:   }
 179: 
 180:   private void inbufWrite() throws IOException
 181:   {
 182:     if (inbufLength > 0)
 183:       {
 184:     int size = inbufLength;
 185:     inbufLength = 0;
 186:     write(inbuf, 0, size);
 187:       }
 188:   }
 189: 
 190:   // Used, if needed, for write(int).
 191:   private byte[] inbuf;
 192:   // Used length of inbuf.
 193:   private int inbufLength;
 194: }