crlfoutputstream.java

CRLF Output Stream

/*
 * @(#)CRLFOutputStream.java	1.3 01/05/23
 *
 * Copyright 1997-2000 Sun Microsystems, Inc. All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * 
 * - Redistribution in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * 
 * Neither the name of Sun Microsystems, Inc. or the names of contributors
 * may be used to endorse or promote products derived from this software
 * without specific prior written permission.
 * 
 * This software is provided "AS IS," without a warranty of any kind. ALL
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES,
 * INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN AND
 * ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES OR LIABILITIES
 * SUFFERED BY LICENSEE AS A RESULT OF  OR RELATING TO USE, MODIFICATION
 * OR DISTRIBUTION OF THE SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL
 * SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR
 * FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE
 * DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY,
 * ARISING OUT OF THE USE OF OR INABILITY TO USE SOFTWARE, EVEN IF SUN HAS
 * BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
 * 
 * You acknowledge that Software is not designed, licensed or intended
 * for use in the design, construction, operation or maintenance of any
 * nuclear facility.
 */

import java.io.*;

/**
 * Convert lines into the canonical MIME format, that is,
 * terminate lines with CRLF. <p>
 *
 * This stream can be used with the Part.writeTo and Message.writeTo
 * methods to generate the canonical MIME format of the data for the
 * purpose of (e.g.) sending it via SMTP or computing a digital
 * signature.
 */
public class CRLFOutputStream extends FilterOutputStream {
    protected int lastb = -1;
    protected static byte[] newline;
    static {
	newline = new byte[2];
	newline[0] = (byte)'\r';
	newline[1] = (byte)'\n';
    }

    public CRLFOutputStream(OutputStream os) {
	super(os);
    }

    public void write(int b) throws IOException {
	if (b == '\r') {
	    out.write(newline);
	} else if (b == '\n') {
	    if (lastb != '\r')
		out.write(newline);
	} else {
	    out.write(b);
	}
	lastb = b;
    }

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

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

	len += off;
	for (int i = start; i < len ; i++) {
	    if (b[i] == '\r') {
		out.write(b, start, i - start);
		out.write(newline);
		start = i + 1;
	    } else if (b[i] == '\n') {
		if (lastb != '\r') {
		    out.write(b, start, i - start);
		    out.write(newline);
		}
		start = i + 1;
	    }
	    lastb = b[i];
	}
	if ((len - start) > 0)
	    out.write(b, start, len - start);
    }
}