Initial revision

From-SVN: r102074

libjava/classpath/java/util/zip/GZIPOutputStream.java

@@ -0,0 +1,151 @@
+/* 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., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 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();
+    int mod_time = (int) (System.currentTimeMillis() / 1000L);
+    byte[] gzipHeader =
+      {
+	/* The two magic bytes */
+	(byte) GZIPInputStream.GZIP_MAGIC,
+	(byte) (GZIPInputStream.GZIP_MAGIC >> 8),
+	  
+	/* The compression type */
+	(byte) Deflater.DEFLATED,
+	
+        /* The flags (not set) */
+	0,
+	
+	/* The modification time */
+	(byte) mod_time, (byte) (mod_time >> 8), 
+	(byte) (mod_time >> 16), (byte) (mod_time >> 24), 
+
+	/* The extra flags */
+	0,
+    
+	/* The OS type (unknown) */
+	(byte) 255
+      };
+
+    out.write(gzipHeader);
+    //    System.err.println("wrote GZIP header (" + gzipHeader.length + " bytes )");
+  }
+
+  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();
+
+    int totalin = def.getTotalIn();
+    int crcval = (int) (crc.getValue() & 0xffffffff);
+
+    //    System.err.println("CRC val is " + Integer.toHexString( crcval ) 		       + " and length " + Integer.toHexString(totalin));
+    
+    byte[] gzipFooter = 
+      {
+	(byte) crcval, (byte) (crcval >> 8),
+	(byte) (crcval >> 16), (byte) (crcval >> 24),
+
+	(byte) totalin, (byte) (totalin >> 8),
+	(byte) (totalin >> 16), (byte) (totalin >> 24)
+      };
+
+    out.write(gzipFooter);
+  //    System.err.println("wrote GZIP trailer (" + gzipFooter.length + " bytes )");    
+  }
+}