| /* GZIPOutputStream.java - Create a file in gzip format |
| Copyright (C) 1999, 2000, 2001 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| package java.util.zip; |
| |
| import java.io.IOException; |
| import java.io.OutputStream; |
| |
| /** |
| * This filter stream is used to compress a stream into a "GZIP" stream. |
| * The "GZIP" format is described in RFC 1952. |
| * |
| * @author John Leuner |
| * @author Tom Tromey |
| * @since JDK 1.1 |
| */ |
| |
| /* Written using on-line Java Platform 1.2 API Specification |
| * and JCL book. |
| * Believed complete and correct. |
| */ |
| |
| public class GZIPOutputStream extends DeflaterOutputStream |
| { |
| /** |
| * CRC-32 value for uncompressed data |
| */ |
| protected CRC32 crc; |
| |
| /** |
| * Creates a GZIPOutputStream with the default buffer size |
| * |
| * @param out The stream to read data (to be compressed) from |
| * |
| */ |
| public GZIPOutputStream(OutputStream out) throws IOException |
| { |
| this(out, 4096); |
| } |
| |
| /** |
| * Creates a GZIPOutputStream with the specified buffer size |
| * |
| * @param out The stream to read compressed data from |
| * @param size Size of the buffer to use |
| */ |
| public GZIPOutputStream(OutputStream out, int size) throws IOException |
| { |
| super(out, new Deflater(Deflater.DEFAULT_COMPRESSION, true), size); |
| crc = new CRC32(); |
| put2(GZIPInputStream.GZIP_MAGIC); |
| out.write(GZIPInputStream.Z_DEFLATED); |
| // No flags for now. |
| out.write(0); |
| // No time either. |
| put2(0); |
| put2(0); |
| // No xflags either. |
| out.write(0); |
| // FIXME: unknown OS. |
| out.write(255); |
| } |
| |
| public synchronized void write(int bval) throws IOException |
| { |
| super.write(bval); |
| crc.update(bval); |
| } |
| |
| public synchronized void write(byte[] buf) throws IOException |
| { |
| write(buf, 0, buf.length); |
| } |
| |
| public synchronized void write(byte[] buf, int off, int len) |
| throws IOException |
| { |
| super.write(buf, off, len); |
| crc.update(buf, off, len); |
| } |
| |
| /** |
| * Writes remaining compressed output data to the output stream |
| * and closes it. |
| */ |
| public void close() throws IOException |
| { |
| finish(); |
| out.close(); |
| } |
| |
| public void finish() throws IOException |
| { |
| super.finish(); |
| put4((int) crc.getValue()); |
| put4(def.getTotalIn()); |
| } |
| |
| private final void put2(int i) throws IOException |
| { |
| out.write(i); |
| out.write(i >> 8); |
| } |
| |
| private final void put4 (int i) throws IOException |
| { |
| out.write(i); |
| out.write(i >> 8); |
| out.write(i >> 16); |
| out.write(i >> 24); |
| } |
| } |