Merge branch 'mc/timer-size-checks'

* mc/timer-size-checks:
  aruino-timer:keywords: add size and empty methods
  README: document size() and empty()
  extras:tests:unitTes: size() and empty() unit tests
  src:arduino-timer: empty() function
  src:arduino-timer: size() function

Author: contrem

README.md

@@ -61,6 +61,16 @@ To **cancel** all *Task*s
 timer.cancel();
 ```
 
+Check if a timer is **empty** - no active *Task*s
+```cpp
+if (timer.empty()) { /* no active tasks */ }
+```
+
+Get the number of active *Task*s
+```cpp
+auto active_tasks = timer.size();
+```
+
 Be fancy with **lambdas**
 ```cpp
 timer.in(1000, [](void*) -> bool { return false; });
@@ -126,6 +136,12 @@ void cancel();
 
 /* Returns the ticks until next event, or 0 if none */
 unsigned long ticks();
+
+/* Number of active tasks in the timer */
+size_t size() const;
+
+/* True if there are no active tasks */
+bool empty() const;
 ```
 
 ### Installation

extras/tests/unitTest/unitTest.ino

@@ -360,6 +360,49 @@ test(timer_ticks) {
     assertEqual(big, timer.ticks()); // big pending again
 }
 
+test(timer_size) {
+    pre_test();
+
+    Timer<0x2, CLOCK::millis, Task *> timer;
+
+    assertEqual(timer.size(), 0UL);
+
+    auto t = make_task();
+
+    auto r = timer.in(0UL, handler, &t);
+
+    assertNotEqual((unsigned long)r, 0UL);
+    assertEqual(timer.size(), 1UL);
+
+    r = timer.in(0UL, handler, &t);
+
+    assertNotEqual((unsigned long)r, 0UL);
+    assertEqual(timer.size(), 2UL);
+
+    timer.cancel();
+
+    assertEqual(timer.size(), 0UL);
+}
+
+test(timer_empty) {
+    pre_test();
+
+    Timer<0x1, CLOCK::millis, Task *> timer;
+
+    assertEqual(timer.empty(), true);
+
+    auto t = make_task();
+
+    auto r = timer.in(0UL, handler, &t);
+
+    assertNotEqual((unsigned long)r, 0UL);
+    assertEqual(timer.empty(), false);
+
+    timer.cancel();
+
+    assertEqual(timer.empty(), true);
+}
+
 test(timer_rollover_every) {
     pre_test();
 

keywords.txt

@@ -20,6 +20,8 @@ every	KEYWORD2
 tick	KEYWORD2
 ticks	KEYWORD2
 cancel	KEYWORD2
+size	KEYWORD2
+empty	KEYWORD2
 
 #######################################
 # Instances (KEYWORD2)

src/arduino-timer.h

@@ -168,6 +168,30 @@ class Timer {
         return ticks;
     }
 
+    /* Number of active tasks in the timer */
+    size_t
+    size() const
+    {
+        size_t s = 0;
+
+        timer_foreach_const_task(task) {
+            if (task->handler) ++s;
+        }
+
+        return s;
+    }
+
+    /* True if there are no active tasks */
+    bool
+    empty() const
+    {
+        timer_foreach_const_task(task) {
+            if (task->handler) return false;
+        }
+
+        return true;
+    }
+
     Timer() : ctr(0), tasks{} {}
 
   private: