/*

GNU-Classpath Extensions: javamail

Copyright (C) 2002 Chris Burdess

For more information on the classpathx please mail:

nferrier@tapsellferrier.co.uk

This program is free software; you can redistribute it and/or

modify it under the terms of the GNU Lesser General Public License

as published by the Free Software Foundation; either version 2

of the License, or (at your option) any later version.

This program 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 program; if not, write to the Free Software

Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

 */

package org.sonews.util.io; // original package: gnu.mail.providers.smtp

import java.io.FilterOutputStream;

import java.io.IOException;

/**

 * An output stream implementing the SMTP specification for dot escaping.

 * Objects of this class are intended to be chained with CRLFOutputStream

 * instances as all SMTP output is intended to be CRLF-escaped.

 *

 * @author dog@gnu.org

 * @version 0.1

 */

public class SMTPOutputStream extends FilterOutputStream {

	/**

	 * The LF octet.

	 */

	public static final int LF = 0x0a;

	/**

	 * The dot octet.

	 */

	public static final int DOT = 0x2e;

	/**

	 * The last octet read.

	 */

	protected int last;

	/**

	 * Constructs an SMTP output stream connected to the specified output stream.

	 * The underlying output stream should coordinate proper CRLF pairs at

	 * line ends.

	 * @param out a CRLFOutputStream

	 */

	public SMTPOutputStream(CRLFOutputStream out) {

		super(out);

	}

	/**

	 * Writes a character to the underlying stream.

	 * @exception IOException if an I/O error occurred

	 */

	@Override

	public void write(int ch) throws IOException {

		if (ch == DOT) {

			if (last == LF) {

				out.write(DOT);

			}

		}

		out.write(ch);

		last = ch;

	}

	/**

	 * Writes a byte array to the underlying stream.

	 * @exception IOException if an I/O error occurred

	 */

	@Override

	public void write(byte b[]) throws IOException {

		write(b, 0, b.length);

	}

	/**

	 * Writes a portion of a byte array to the underlying stream.

	 * @exception IOException if an I/O error occurred

	 */

	@Override

	public void write(byte b[], int off, int len) throws IOException {

		int d = off;

		len += off;

		for (int i = off; i < len; i++) {

			switch (b[i]) {

				case DOT:

					int l = (i - d);

					if (l > 0) {

						out.write(b, d, l);

					}

					d = i;

					if (last == LF) {

						out.write(DOT);

					}

					break;

			}

			last = b[i];

		}

		if (len - d > 0) {

			out.write(b, d, len - d);

		}

	}

}