upper bound for elapsed time

2 files changed, 6 insertions, 2 deletions

diff --git a/src/components/stopwatch/StopWatchController.cpp b/src/components/stopwatch/StopWatchController.cpp
index 311bccc7..64261055 100644
--- a/src/components/stopwatch/StopWatchController.cpp
+++ b/src/components/stopwatch/StopWatchController.cpp
@@ -14,8 +14,8 @@ void StopWatchController::Start() {
 }
 
 void StopWatchController::Pause() {
+  timeElapsedPreviously = GetElapsedTime();
   currentState = StopWatchStates::Paused;
-  timeElapsedPreviously += xTaskGetTickCount() - startTime;
 }
 
 void StopWatchController::Clear() {
@@ -55,7 +55,8 @@ TickType_t StopWatchController::GetElapsedTime() {
   if (!IsRunning()) {
     return timeElapsedPreviously;
   }
-  return timeElapsedPreviously + (xTaskGetTickCount() - startTime);
+  TickType_t delta = xTaskGetTickCount() - startTime;
+  return (timeElapsedPreviously + delta) % elapsedTimeBoundary;
 }
 
 bool StopWatchController::IsRunning() {
diff --git a/src/components/stopwatch/StopWatchController.h b/src/components/stopwatch/StopWatchController.h
index 0791701c..6aaec2b2 100644
--- a/src/components/stopwatch/StopWatchController.h
+++ b/src/components/stopwatch/StopWatchController.h
@@ -46,6 +46,8 @@ namespace Pinetime {
       bool IsPaused();
 
     private:
+      // Time at which stopwatch wraps around to zero (1000 hours)
+      TickType_t elapsedTimeBoundary = configTICK_RATE_HZ * 60 * 60 * 1000;
       // Current state of stopwatch
       StopWatchStates currentState = StopWatchStates::Cleared;
       // Start time of current duration
@@ -55,6 +57,7 @@ namespace Pinetime {
 
       // Maximum number of stored laps
       static constexpr int histSize = 2;
+      // Value at which lap numbers wrap around to zero
       static constexpr int lapNumberBoundary = 1000;
       // Lap storage
       Utility::CircularBuffer<LapInfo, histSize> history;