CorrectedGZIPInputStream.java

// BlogBridge -- RSS feed reader, manager, and web based service
// Copyright (C) 2002-2006 by R. Pito Salas
//
// This program is free software; you can redistribute it and/or modify it under
// the terms of the GNU 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
//
// Contact: R. Pito Salas
// mailto:pitosalas@users.sourceforge.net
// More information: about BlogBridge
// http://www.blogbridge.com
// http://sourceforge.net/projects/blogbridge
//
// $Id: CorrectedGZIPInputStream.java,v 1.1 2007/04/13 12:56:43 spyromus Exp $
//

package com.salas.bb.utils.net;

import java.io.IOException;
import java.io.InputStream;
import java.util.zip.GZIPInputStream;

/**
 * The stream that's ignoring problems with premature GZIP trailer.
 */
public class CorrectedGZIPInputStream extends GZIPInputStream
{
    private final Object foundErrorLock = new Object();
    private boolean foundError = false;

    /**
     * Creates the stream.
     *
     * @param in    input stream.
     *
     * @throws java.io.IOException I/O exception.
     */
    public CorrectedGZIPInputStream(InputStream in)
        throws IOException
    {
        super(in);
    }

    @Override
    public int read(byte[] buf, int off, int len)
        throws IOException
    {
        int justRead = -1;

        synchronized (foundErrorLock)
        {
            if (!foundError)
            {
                try
                {
                    justRead = super.read(buf, off, len);
                } catch (IOException ex)
                {
                    if (ex.getMessage().indexOf("Corrupt GZIP trailer") != -1)
                    {
                        foundError = true;
                        justRead = -1;
                    } else throw ex;
                }
            }
        }

        return justRead;
    }
}