/**
 * This file Copyright (c) 2011-2012 Magnolia International
 * Ltd.  (http://www.magnolia-cms.com). All rights reserved.
 *
 *
 * This file is dual-licensed under both the Magnolia
 * Network Agreement and the GNU General Public License.
 * You may elect to use one or the other of these licenses.
 *
 * This file is distributed in the hope that it will be
 * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
 * implied warranty of MERCHANTABILITY or FITNESS FOR A
 * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
 * Redistribution, except as permitted by whichever of the GPL
 * or MNA you select, is prohibited.
 *
 * 1. For the GPL license (GPL), you can redistribute and/or
 * modify this file under the terms of the GNU General
 * Public License, Version 3, as published by the Free Software
 * Foundation.  You should have received a copy of the GNU
 * General Public License, Version 3 along with this program;
 * if not, write to the Free Software Foundation, Inc., 51
 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * 2. For the Magnolia Network Agreement (MNA), this file
 * and the accompanying materials are made available under the
 * terms of the MNA which accompanies this distribution, and
 * is available at http://www.magnolia-cms.com/mna.html
 *
 * Any modifications to this file must keep this entire header
 * intact.
 *
 */
package info.magnolia.cms.filters;

import info.magnolia.cms.filters.RangeSupportFilter.RangeInfo;

import java.io.IOException;

import javax.servlet.ServletOutputStream;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Range limited output stream. Will output only bytes in given range, ignoring the rest.
 * 
 * @version $Id$
 * 
 */
public class RangedOutputStream extends ServletOutputStream {

    private static final Logger log = LoggerFactory.getLogger(RangedOutputStream.class);

    private final ServletOutputStream out;

    private long writtenCount = 0;

    private final RangeInfo range;

    public RangedOutputStream(ServletOutputStream stream, RangeInfo range) {
        log.debug("Using ranged stream");
        out = stream;
        this.range = range;
    }

    @Override
    public void write(int b) throws IOException {
        if (writtenCount >= range.start && writtenCount <= range.end) {
            out.write(b);
        }
        writtenCount++;
    }

    @Override
    public void close() throws IOException {
        int rangeLen = range.end - range.start;
        int written = (int) Math.min(rangeLen, writtenCount);
        log.debug("Closing ranged stream after writing {} bytes into range {} bytes of total {} received bytes", new Object[] { written, rangeLen, writtenCount });
        super.close();
    }
}