Update Events example to use Chrono times (#124)

* Update Events example to use Chrono times

Also show how to use non_periodic and cancel.

* Fix astyle spurious whitespace issues

* Further whitespace removal

* Add timestamp to event printf and add expected results

Author: adbridge

APIs_RTOS/Events_ex_1/main.cpp

@@ -7,40 +7,97 @@
 // Creates an event bound to the specified event queue
 EventQueue queue;
 void handler(int count);
-Event<void(int)> event(&queue, handler);
+Event<void(int)> event1(&queue, handler);
+Event<void(int)> event2(&queue, handler);
+
 
 void handler(int count)
 {
-    printf("Event = %d \n", 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.
-    event.post(1);
-    event.post(2);
-    event.post(3);
+    // 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
-    event.delay(100);       // Starting delay - 100 msec
-    event.period(200);      // Delay between each evet - 200msec
+    // 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
-    queue.dispatch(400);        // Dispatch time - 400msec
-    // 400 msec - Only 2 set of events will be dispatched as period is 200 msec
+    // 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(800);
 
     event_thread.join();
+
 }