function download($file)
{
    $fp = @fopen($file, 'rb');
    $size   = filesize($file); // File size
    $length = $size;           // Content length
    $start  = 0;               // Start byte
    $end    = $size - 1;       // End byte
    header('Content-type: octet-stream');
    header("Accept-Ranges: 0-$length");
    if (isset($_SERVER['HTTP_RANGE'])) {
        $cStart = $start;
        $cEnd   = $end;
        list(, $range) = explode('=', $_SERVER['HTTP_RANGE'], 2);
        if (strpos($range, ',') !== false) {
            header('HTTP/1.1 416 Requested Range Not Satisfiable');
            header("Content-Range: bytes $start-$end/$size");
            exit;
        }
        if ($range == '-') {
            $cStart = $size - substr($range, 1);
        }else{
            $range  = explode('-', $range);
            $cStart = $range[0];
            $cEnd   = (isset($range[1]) && is_numeric($range[1])) ? $range[1] : $size;
        }
        $cEnd = ($cEnd > $end) ? $end : $cEnd;
        if ($cStart > $cEnd || $cStart > $size - 1 || $cEnd >= $size) {
            header('HTTP/1.1 416 Requested Range Not Satisfiable');
            header("Content-Range: bytes $start-$end/$size");
            exit;
        }
        $start  = $cStart;
        $end    = $cEnd;
        $length = $end - $start + 1;
        fseek($fp, $start);
        header('HTTP/1.1 206 Partial Content');
    }
    header("Content-Range: bytes $start-$end/$size");
    header("Content-Length: " . $length);
    $buffer = 1024 * 8;
    while(!feof($fp) && ($p = ftell($fp)) <= $end) {
        if ($p + $buffer > $end) {
            $buffer = $end - $p + 1;
        }
        set_time_limit(0);
        echo fread($fp, $buffer);
        flush();
    }
    fclose($fp);
    exit();
}