GZIPOutputStream.java

//

package net.sf.zipme;
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
 */
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);
    hook();
    int mod_time=(int)(System.currentTimeMillis() / 1000L);
    byte[] gzipHeader={(byte)GZIPInputStream.GZIP_MAGIC,(byte)(GZIPInputStream.GZIP_MAGIC >> 8),(byte)Deflater.DEFLATED,0,(byte)mod_time,(byte)(mod_time >> 8),(byte)(mod_time >> 16),(byte)(mod_time >> 24),0,(byte)255};
    out.write(gzipHeader);
  }
  public void hook(){
  }
  public synchronized void write(  byte[] buf,  int off,  int len) throws IOException {
    super.write(buf,off,len);
    this.hook31(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();
    byte[] gzipFooter=new byte[8];
    hook2(gzipFooter);
    gzipFooter[4]=(byte)totalin;
    gzipFooter[5]=(byte)(totalin >> 8);
    gzipFooter[6]=gzipFooter[3]=(byte)(totalin >> 16);
    gzipFooter[7]=(byte)(totalin >> 24);
    out.write(gzipFooter);
  }
  private void hook2(  byte[] gzipFooter){
    new GZIPOutputStream_hook22(this,gzipFooter).execute();
  }
  protected void hook31(  byte[] buf,  int off,  int len) throws IOException {
  }
}