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/*
 * Copyright (c) 1997, 2023 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0, which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the
 * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
 * version 2 with the GNU Classpath Exception, which is available at
 * https://www.gnu.org/software/classpath/license.html.
 *
 * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
 */

package org.eclipse.angus.mail.util;

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


/**
 * Convert lines into the canonical format, that is, terminate lines with the
 * CRLF sequence.
 *
 * @author John Mani
 */
public class CRLFOutputStream extends FilterOutputStream {
    protected int lastb = -1;
    protected boolean atBOL = true;    // at beginning of line?
    private static final byte[] newline = {(byte) '\r', (byte) '\n'};

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

    @Override
    public void write(int b) throws IOException {
        if (b == '\r') {
            writeln();
        } else if (b == '\n') {
            if (lastb != '\r')
                writeln();
        } else {
            out.write(b);
            atBOL = false;
        }
        lastb = b;
    }

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

    @Override
    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);
                writeln();
                start = i + 1;
            } else if (b[i] == '\n') {
                if (lastb != '\r') {
                    out.write(b, start, i - start);
                    writeln();
                }
                start = i + 1;
            }
            lastb = b[i];
        }
        if ((len - start) > 0) {
            out.write(b, start, len - start);
            atBOL = false;
        }
    }

    /*
     * Just write out a new line, something similar to out.println()
     */
    public void writeln() throws IOException {
        out.write(newline);
        atBOL = true;
    }
}