private int fillbuf() throws IOException {
        if (markpos == -1 || (pos - markpos >= marklimit)) {
            /* Mark position not set or exceeded readlimit */
            int result = in.read(buf);
            if (result > 0) {
                markpos = -1;
                pos = 0;
                count = result == -1 ? 0 : result;
            }
            return result;
        }
        if (markpos == 0 && marklimit > buf.length) {
            /* Increase buffer size to accomodate the readlimit */
            int newLength = buf.length * 2;
            if (newLength > marklimit) {
                newLength = marklimit;
            }
            byte[] newbuf = new byte[newLength];
            System.arraycopy(buf, 0, newbuf, 0, buf.length);
            buf = newbuf;
        } else if (markpos > 0) {
            System.arraycopy(buf, markpos, buf, 0, buf.length - markpos);
        }
        /* Set the new position and mark position */
        pos -= markpos;
        count = markpos = 0;
        int bytesread = in.read(buf, pos, buf.length - pos);
        count = bytesread <= 0 ? pos : pos + bytesread;
        return bytesread;
    }