InputController

class InputController
{
    class InputValidator
    {
    public:
        virtual bool Invoke() const = 0;
    };

    class GenericInputValidator : public InputValidator
    {
    public:
        virtual bool Invoke() const { return this->Invoke(); }
    private:
        char m_storage[32];
    };

    template<typename Device, typename Function, typename Button>
    class InputValidatorWrapper : public InputValidator
    {
    public:
        InputValidatorWrapper(Device * device, Function function, Button button)
            : m_device(device)
            , m_function(function)
            , m_button(button)
        {}

        virtual bool Invoke() const { return (m_device->*m_function)(m_button); };
    private:
        Device *    m_device;
        Function    m_function;
        Button      m_button;
    };
public:
    InputController()
        : m_index(0)
    {
    }

    template<typename Device, typename Function, typename Button>
    void AddInput(Device * device, Function funct, Button button)
    {
        new (&m_validators[m_index]) InputValidatorWrapper<Device, Function, Button>(device, funct, button);

        m_index++;
    }

    bool IsAnyTriggered()
    {
        bool result = NS_FALSE;

        for (size_t i = 0; i < m_index; ++i)
        {
            result |= m_validators[i].Invoke();
        }

        return result;
    }

private:
    static constexpr size_t MAX_INPUTS = 16;

    GenericInputValidator m_validators[MAX_INPUTS];
    size_t m_index;
};