repos/Callback_35/Callback_35/Header.h

#pragma once

/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 *
 */

 /**
  * Basic std::function callback example. Templated on a function signature
  * that takes in a uint32_t and returns void.
  */

struct myData {
    int myAge = 55;
    const char* pchar = "myData struct";
    enum en_sex { MALE, FEMALE, DIVERS } sex = MALE;
};

struct myOtherData : myData {
    int myOtherAge = 35;
};


/**
 * Alternative storage implementation.  Perhaps you want to store
 * callbacks for different event types?
 */
enum my_events_t
{
    VIDEO_STOP = 0,
    VIDEO_START,
    VIDEO_PAUS,
    EVENT_MAX
};

/**
 * Alternative storage implementation.  Perhaps you want to store
 * callbacks for different event types?
 */
struct cb_event_t
{
	std::function<void(myData)> cb;
	my_events_t event;
};



/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 *
 */



/***********************************************************************************************************************
 * Dummy Client #1
 * Uses a static method for a callback.
 */
class Client1
{
public:
    static void func(myData v)
    {
        printf("static member callback: %d\n", v.myAge);
    }
};

/***********************************************************************************************************************
 * Dummy Client #2
 * Uses an instance method as a callback
 */
class Client2
{
public:
    void func(myData v) const
    {
        printf("instance member callback: %d\n", v.myAge);
    }
};

/***********************************************************************************************************************
 *    Callback on a c function
 */
extern "C"
{
    static void c_client_callback(myData v)
    {
        printf("C function callback: %d\n", v.myAge);
    }
}


/**
 * Event based example.  Constructed with a uint32_t.
 * Callbacks are passed this uint32_t.
 * Callbacks are only invoked when their event type matches the
 * occuring event.
 */
class EventDriver
{

	typedef std::function<void(myData)> cb_t;

public:

	EventDriver() : callbacks_() {};

	// Register a callback.
	void register_callback(const cb_t& cb, const my_events_t event)
	{
		// add callback to end of callback list
		callbacks_.push_back({ cb, event });
	}

	/// Call all the registered callbacks.
	void callback(myData& val, my_events_t event) const
	{
		// my_events_t event = VIDEO_START;
		// iterate through callback list and call each one
		for (const auto& cb : callbacks_)
		{
			if (cb.event == event)
			{
				cb.cb(val);
			}
		}
	}

private:
	/// Integer to pass to callbacks.
	// myData &val_ ;
	/// List of callback functions.
	std::vector<cb_event_t> callbacks_;
};