libjava/java/util/zip/GZIPOutputStream.java

   1 /* GZIPOutputStream.java - Create a file in gzip format
   2    Copyright (C) 1999, 2000, 2001 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.IOException;
  41 import java.io.OutputStream;
  42
  43 /**
  44  * @author Tom Tromey
  45  * @date May 17, 1999
  46  */
  47
  48 /* Written using on-line Java Platform 1.2 API Specification
  49  * and JCL book.
  50  * Believed complete and correct.
  51  */
  52
  53 public class GZIPOutputStream extends DeflaterOutputStream
  54 {
  55   public void close () throws IOException
  56   {
  57     finish ();
  58     out.close ();
  59   }
  60
  61   public void finish () throws IOException
  62   {
  63     super.finish();
  64     put4 ((int) crc.getValue());
  65     put4 (def.getTotalIn());
  66   }
  67
  68   public GZIPOutputStream (OutputStream out) throws IOException
  69   {
  70     this (out, 512);
  71   }
  72
  73   public GZIPOutputStream (OutputStream out, int readsize) throws IOException
  74   {
  75     super (out, new Deflater (Deflater.DEFAULT_COMPRESSION, true), readsize);
  76
  77     put2 (GZIPInputStream.GZIP_MAGIC);
  78     out.write (GZIPInputStream.Z_DEFLATED);
  79     // No flags for now.
  80     out.write (0);
  81     // No time either.
  82     put2 (0);
  83     put2 (0);
  84     // No xflags either.
  85     out.write (0);
  86     // FIXME: unknown OS.
  87     out.write (255);
  88
  89     crc = new CRC32 ();
  90   }
  91
  92   public synchronized void write (int bval) throws IOException
  93   {
  94     super.write (bval);
  95     crc.update (bval);
  96   }
  97
  98   public synchronized void write (byte[] buf) throws IOException
  99   {
 100     write (buf, 0, buf.length);
 101   }
 102
 103   public synchronized void write (byte[] buf, int off, int len)
 104     throws IOException
 105   {
 106     super.write(buf, off, len);
 107     crc.update(buf, off, len);
 108   }
 109
 110   private final void put2 (int i) throws IOException
 111   {
 112     out.write (i);
 113     out.write (i >> 8);
 114   }
 115
 116   private final void put4 (int i) throws IOException
 117   {
 118     out.write (i);
 119     out.write (i >> 8);
 120     out.write (i >> 16);
 121     out.write (i >> 24);
 122   }
 123
 124   // Checksum used by this stream.
 125   protected CRC32 crc;
 126 }