Merge pull request #49 from sy-c/master

Timer::increment()

Author: sy-c

include/Common/Timer.h

@@ -45,7 +45,9 @@ class Timer
   /// Reset timer by adding timeout value to starting time value.
   /// Usefull when called in loops, prevents loosing time elapsed after previous timeout.
   /// (e.g.: to implement timeout every 1 second without drift in time)
-  void increment();
+  /// If ensureFuture is true, value is incremented until next occurence is in the future (and only if timeout has occured already),
+  /// to avoid possibly several successive immediate timeouts again when multiple timeout periods have been missed.
+  void increment(bool ensureFuture = false);
 
   /// Check if time elapsed since timer reset (or last increment set) is bigger than timeout value set.
   /// \return Returns 1 if timeout, 0 otherwise.

src/Timer.cxx

@@ -36,9 +36,17 @@ void Timer::reset(int timeout)
   tmax = timeout / 1000000.0;
 }
 
-void Timer::increment()
+void Timer::increment(bool ensureFuture)
 {
-  t0 += std::chrono::microseconds((int)(tmax * 1000000.0));
+  if (ensureFuture) {
+    double tnext = getRemainingTime();
+    if ((tnext <= 0) && (tmax > 0)) {
+      int n = (int)(1 - (tnext / tmax));
+      t0 += std::chrono::microseconds((int)(n * tmax * 1000000.0));
+    }
+  } else {
+    t0 += std::chrono::microseconds((int)(tmax * 1000000.0));
+  }
 }
 
 int Timer::isTimeout()
@@ -64,4 +72,3 @@ double Timer::getRemainingTime()
 
 } // namespace Common
 } // namespace AliceO2
-

test/testTimer.cxx

@@ -40,6 +40,24 @@ BOOST_AUTO_TEST_CASE(timer_test)
     success = 1;
   }
 
+  // test increment
+  printf("\nTest increment (ensureFuture=0)\n");
+  // this should blindly increase by fixed amount of time
+  t.reset(100000);
+  usleep(350000);
+  for (int i = 1; i <= 5; i++) {
+    printf("iteration %d : timeout = %d timeRemaining = %.2fs\n", i, (int)t.isTimeout(), t.getRemainingTime());
+    t.increment(0);
+  }
+  printf("\nTest increment (ensureFuture=1)\n");
+  // this should update timeout to next occurence, with respect to start and given period
+  t.reset(100000);
+  usleep(250000);
+  for (int i = 1; i <= 5; i++) {
+    printf("iteration %d : timeout = %d timeRemaining = %.2fs\n", i, (int)t.isTimeout(), t.getRemainingTime());
+    t.increment(1);
+  }
+
   BOOST_CHECK_EQUAL(success, 1);
 }