package support;

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

/**
 * Implementation that immediately returns uncompressed data available from an
 * input stream. Adapted from
 * https://dev.twitter.com/docs/streaming-apis/processing.
 */
public class StreamingGZIPInputStream extends GZIPInputStream {

    private final InputStream wrapped;

    public StreamingGZIPInputStream(InputStream is) throws IOException {
        super(is);
        wrapped = is;
    }

    /**
     * Overrides behavior of GZIPInputStream which assumes we have all the data
     * available which is not true for streaming. We instead rely on the
     * underlying stream to tell us how much data is available.
     *
     * Programs should not count on this method to return the actual number of
     * bytes that could be read without blocking.
     *
     * @return whatever the wrapped InputStream returns.
     * @exception IOException if an I/O error occurs.
     */
    @Override
    public int available() throws IOException {
        return wrapped.available();
    }
}