Quadcap Embeddable Server

com/quadcap/io/DotStuffOutputStream.java

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package com.quadcap.io;

/* Copyright 1997 - 2003 Quadcap Software.  All rights reserved.
 *
 * This software is distributed under the Quadcap Free Software License.
 * This software may be used or modified for any purpose, personal or
 * commercial.  Open Source redistributions are permitted.  Commercial
 * redistribution of larger works derived from, or works which bundle
 * this software requires a "Commercial Redistribution License"; see
 * http://www.quadcap.com/purchase.
 *
 * Redistributions qualify as "Open Source" under  one of the following terms:
 *   
 *    Redistributions are made at no charge beyond the reasonable cost of
 *    materials and delivery.
 *
 *    Redistributions are accompanied by a copy of the Source Code or by an
 *    irrevocable offer to provide a copy of the Source Code for up to three
 *    years at the cost of materials and delivery.  Such redistributions
 *    must allow further use, modification, and redistribution of the Source
 *    Code under substantially the same terms as this license.
 *
 * Redistributions of source code must retain the copyright notices as they
 * appear in each source code file, these license terms, and the
 * disclaimer/limitation of liability set forth as paragraph 6 below.
 *
 * Redistributions in binary form must reproduce this Copyright Notice,
 * these license terms, and the disclaimer/limitation of liability set
 * forth as paragraph 6 below, in the documentation and/or other materials
 * provided with the distribution.
 *
 * The Software is provided on an "AS IS" basis.  No warranty is
 * provided that the Software is free of defects, or fit for a
 * particular purpose.  
 *
 * Limitation of Liability. Quadcap Software shall not be liable
 * for any damages suffered by the Licensee or any third party resulting
 * from use of the Software.
 */

import java.io.*;

import com.quadcap.util.Debug;
import com.quadcap.util.Util;

/**
 * A filter output stream that performs dot-stuffing.
 *
 * @author Stan Bailes
 */

public class DotStuffOutputStream extends OutputStream {
    OutputStream        out;
    
    static final int    INIT    = 0;
    static final int    SEENCR  = 1;
    static final int    SEENLF  = 2;

    static final byte   CR      = (byte)'\r';
    static final byte   LF      = (byte)'\n';

    static final byte[] endTag  = { CR, LF, (byte)'.', CR, LF };
    
    int state = SEENLF;
    
    public DotStuffOutputStream(OutputStream os) {
        this.out = os;
    }

    public void write(int b) throws IOException {
        switch (state) {
        case INIT:
            if (b == CR) state = SEENCR;
            break;
        case SEENCR:
            if (b == LF) state = SEENLF;
            else if (b != CR) state = INIT;
            break;
        case SEENLF:
            if (b == '.') {
                out.write('.');
                state = INIT;
            } else if (b == CR) {
                state = SEENCR;
            } else {
                state = INIT;
            }
            break;
        }
        out.write(b);
    }

    public void write(byte[] buf, int offset, int len) throws IOException {
        for (int i = 0; i < len; i++) {
            this.write(buf[i]);
        }
    }

    public void writeFinal() throws IOException {
        int start = 0;
        int cnt = endTag.length - start;
        out.write(endTag, start, cnt);
        out.flush();
    }
}