Event

/*
 * Copyright (c) 2020 Arm Limited and affiliates.
 * SPDX-License-Identifier: Apache-2.0
 */
#include "mbed.h"

// Creates an event bound to the specified event queue
EventQueue queue;
void handler(int count);
Event<void(int)> event1(&queue, handler);
Event<void(int)> event2(&queue, handler);


void handler(int count)
{
    unsigned time_ms = equeue_tick();
    printf("Timestamp = %d Event = %d \n", time_ms, count);
    return;
}

void post_events(void)
{
    // Events can be posted multiple times and enqueue gracefully until
    // the dispatch function is called. Each event will be processed
    // subject to any delay and period specified. Each time an event has
    // been dispatched it will be re-queued ready for the next dispatch
    // period.
    event1.post(1);      // Event1 with a value of 1
    event1.post(2);      // Event1 with a value of 2
    event1.post(3);      // Event1 with a value of 3

    // Cancel the last event posted ie Event1 with a value of 3
    event1.cancel();

    event1.post(4);      // Event1 with a value of 4

    event2.post(5);      // Event2 with a value of 5

}


// Example  demonstrates the following:
// 1. Post 5 different events to a queue
// 2. Configure the event delay and period for each
// 3. Invoke the dispatcher to dispatch events for a specified period
//
//    | 100ms |    200ms    | 100ms | 100ms |    200ms     |
//            ^             ^       ^       ^              ^
//       Events 1,2,4       ^       ^       ^              ^
//        dispatched        ^       ^       ^              ^
//                          ^       ^       ^              ^
//                   Events 1,2,4   ^       ^              ^
//                    dispatched    ^       ^              ^
//                                  ^       ^              ^
//                               Event 5    ^              ^
//                                          ^              ^
//                                      Event 1,2,4        ^
//                                       dispatched        ^
//                                                         ^
//                                                       Events 1,2,4
//                                                        dispatched
//
// Expected Output
//
// Timestamp = 100 Event = 1
// Timestamp = 127 Event = 2
// Timestamp = 156 Event = 4
// Timestamp = 300 Event = 1
// Timestamp = 327 Event = 2
// Timestamp = 356 Event = 4
// Timestamp = 400 Event = 5
// Timestamp = 500 Event = 1
// Timestamp = 527 Event = 2
// Timestamp = 556 Event = 4
// Timestamp = 700 Event = 1
// Timestamp = 727 Event = 2
// Timestamp = 756 Event = 4

int main()
{
    // Example 1 Dispatch posted events for a specified period
    Thread event_thread;

    // The event can be manually configured for special timing requirements
    // specified in milliseconds (using Chrono durations)
    event1.delay(100ms);       // Starting delay - 100 msec
    event1.period(200ms);      // Delay between each event - 200msec

    event2.delay(400ms);           // Starting delay - 400 msec
    event2.period(non_periodic);   // Single non periodic event

    event_thread.start(callback(post_events));

    // Posted events are dispatched in the context of the queue's
    // dispatch function. Note that the EventQueue library has yet to be
    // converted to using Chrono times and thus times are still specified
    // in integer millisecond units.
    // 800 ms will allow the posted events to be dispatched multiple times
    queue.dispatch_for(800ms);

    event_thread.join();

}