/*
 * BlockOutputStream.java
 * Copyright (C) 2003 The Free Software Foundation
 * 
 * This file is part of GNU inetlib, a library.
 * 
 * GNU inetlib 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 of the License, or
 * (at your option) any later version.
 * 
 * GNU inetlib 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 this library; 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
 * obliged to do so.  If you do not wish to do so, delete this
 * exception statement from your version.
 */

package gnu.inet.ftp;

import java.io.FilterOutputStream;
import java.io.IOException;
import java.io.OutputStream;

/**
 * A DTP output stream that implements the FTP block transfer mode.
 *
 * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a>
 */
class BlockOutputStream
  extends DTPOutputStream
{

  static final byte RECORD = -128;      // 0x80
  static final byte EOF = 64;   // 0x40

  BlockOutputStream(DTP dtp, OutputStream out)
  {
    super(dtp, out);
  }

  public void write(int c)
    throws IOException
  {
    if (transferComplete)
      {
        return;
      }
    byte[] buf = new byte[]
      {
        RECORD,                 /* record descriptor */
        0x00, 0x01,             /* one byte */
        (byte) c                /* the byte */
      };
    out.write(buf, 0, 4);
  }

  public void write(byte[] b)
    throws IOException
  {
    write(b, 0, b.length);
  }

  public void write(byte[] b, int off, int len)
    throws IOException
  {
    if (transferComplete)
      {
        return;
      }
    byte[] buf = new byte[len + 3];
    buf[0] = RECORD;            /* record descriptor */
    buf[1] = (byte) ((len & 0x00ff) >> 8);      /* high byte of bytecount */
    buf[2] = (byte) (len & 0xff00);     /* low byte of bytecount */
    System.arraycopy(b, off, buf, 3, len);
    out.write(buf, 0, len);
  }

  public void close()
    throws IOException
  {
    byte[] buf = new byte[]
      {
        EOF,                    /* eof descriptor */
        0x00, 0x00              /* no bytes */
      };
    out.write(buf, 0, 3);
    super.close();
  }

}

