blockoutputstream.java

kaffe Java 解释器语言,源码,Java的子集系统,开放源代码

/*
 * $Id: BlockOutputStream.java,v 1.1 2004/01/10 23:34:31 dalibor Exp $
 * 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
 * 
 * As a special exception, if you link this library with other files to
 * produce an executable, this library does not by itself cause the
 * resulting executable to be covered by the GNU General Public License.
 * This exception does not however invalidate any other reasons why the
 * executable file might be covered by the GNU General Public License.
 */

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:[e-mail]'>Chris Burdess</a>
 * @version $Revision: 1.1 $ $Date: 2004/01/10 23:34:31 $
 */
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();
    }

}