Performs a 32-bit left shift operation (<<) even on a 64-bit machine

leftshift32

    /**
     * Performs a 32-bit left shift operation (<<) even on a 64-bit machine
     *
     * @param integer $number Shift these bits
     *
     * @param integer $steps Step this many times
     *
     * @return string Returns the integer
     */
    function leftshift32 ($number, $steps)
    {
        if (PHP_INT_MAX == 2147483647) {
            return $number << $steps;
        }
        $binary = decbin($number) . str_repeat('0', $steps);
        $binary = str_pad($binary, 32, '0', STR_PAD_LEFT);
        $binary = substr($binary, strlen($binary) - 32);
        return $binary{0} == '1' ? -(pow(2, 31) - bindec(substr($binary, 1))) : bindec($binary);
    }