mirror of git://gcc.gnu.org/git/gcc.git
147 lines
4.0 KiB
Java
147 lines
4.0 KiB
Java
/* GZIPOutputStream.java - Create a file in gzip format
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Copyright (C) 1999, 2000, 2001 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301 USA.
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Linking this library statically or dynamically with other modules is
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making a combined work based on this library. Thus, the terms and
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conditions of the GNU General Public License cover the whole
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combination.
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent
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modules, and to copy and distribute the resulting executable under
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terms of your choice, provided that you also meet, for each linked
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independent module, the terms and conditions of the license of that
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module. An independent module is a module which is not derived from
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or based on this library. If you modify this library, you may extend
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this exception to your version of the library, but you are not
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obligated to do so. If you do not wish to do so, delete this
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exception statement from your version. */
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package java.util.zip;
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import java.io.IOException;
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import java.io.OutputStream;
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/**
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* This filter stream is used to compress a stream into a "GZIP" stream.
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* The "GZIP" format is described in RFC 1952.
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*
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* @author John Leuner
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* @author Tom Tromey
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* @since JDK 1.1
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*/
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/* Written using on-line Java Platform 1.2 API Specification
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* and JCL book.
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* Believed complete and correct.
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*/
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public class GZIPOutputStream extends DeflaterOutputStream
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{
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/**
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* CRC-32 value for uncompressed data
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*/
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protected CRC32 crc;
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/**
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* Creates a GZIPOutputStream with the default buffer size
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*
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* @param out The stream to read data (to be compressed) from
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*
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*/
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public GZIPOutputStream(OutputStream out) throws IOException
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{
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this(out, 4096);
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}
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/**
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* Creates a GZIPOutputStream with the specified buffer size
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*
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* @param out The stream to read compressed data from
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* @param size Size of the buffer to use
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*/
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public GZIPOutputStream(OutputStream out, int size) throws IOException
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{
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super(out, new Deflater(Deflater.DEFAULT_COMPRESSION, true), size);
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crc = new CRC32();
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put2(GZIPInputStream.GZIP_MAGIC);
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out.write(GZIPInputStream.Z_DEFLATED);
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// No flags for now.
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out.write(0);
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// No time either.
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put2(0);
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put2(0);
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// No xflags either.
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out.write(0);
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// FIXME: unknown OS.
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out.write(255);
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}
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public synchronized void write(int bval) throws IOException
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{
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super.write(bval);
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crc.update(bval);
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}
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public synchronized void write(byte[] buf) throws IOException
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{
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write(buf, 0, buf.length);
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}
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public synchronized void write(byte[] buf, int off, int len)
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throws IOException
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{
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super.write(buf, off, len);
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crc.update(buf, off, len);
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}
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/**
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* Writes remaining compressed output data to the output stream
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* and closes it.
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*/
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public void close() throws IOException
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{
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finish();
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out.close();
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}
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public void finish() throws IOException
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{
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super.finish();
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put4((int) crc.getValue());
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put4(def.getTotalIn());
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}
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private final void put2(int i) throws IOException
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{
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out.write(i);
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out.write(i >> 8);
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}
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private final void put4 (int i) throws IOException
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{
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out.write(i);
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out.write(i >> 8);
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out.write(i >> 16);
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out.write(i >> 24);
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}
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}
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