Solved condition timed wait unsigned overflow bug.

The comparison of absolute times was done in a wrong way such that
unsigned int overflows occured in the windows implementation when
the time to wait for had been passed already. A very big time to
wait for resulted, i.e., a deadlock.

EMBB-466

base_c/src/condition_variable.c

@@ -83,8 +83,8 @@ int embb_condition_wait_until(embb_condition_t* condition_var,
   embb_time_t now;
   embb_time_now(&now);
   /* Check if absolute timepoint (in milliseconds) still is in the future */
-  if (time->seconds * 1000 + time->nanoseconds / 1000000
-      - now.seconds * 1000 - now.nanoseconds / 1000000 > 0) {
+  if ((time->seconds * 1000 + time->nanoseconds / 1000000)
+      > (now.seconds * 1000 + now.nanoseconds / 1000000)) {
     /* Convert to (unsigned type) milliseconds and round up */
     DWORD time_diff = (DWORD) (
         time->seconds * 1000 + time->nanoseconds / 1000000

base_c/test/condition_var_test.cc

@@ -105,7 +105,7 @@ void ConditionVarTest::TestTimedWaitTimeouts() {
   embb_time_t time;
   embb_duration_t duration = EMBB_DURATION_INIT;
 
-  // Wait for now tests already passed time point
+  // Wait for "now" tests already passed time point
   embb_time_now(&time);
   embb_mutex_lock(&mutex);
   int status = embb_condition_wait_until(&cond, &mutex, &time);

base_c/test/time_test.cc

@@ -36,6 +36,7 @@ namespace test {
 
 TimeTest::TimeTest() {
   CreateUnit("Time in duration").Add(&TimeTest::TestTimeInDuration, this);
+  CreateUnit("Monotonicity").Add(&TimeTest::TestMonotonicity, this, 1, partest::TestSuite::GetDefaultNumIterations() * 10);
 }
 
 void TimeTest::TestTimeInDuration() {
@@ -48,6 +49,18 @@ void TimeTest::TestTimeInDuration() {
   PT_EXPECT_EQ(status, EMBB_SUCCESS);
 }
 
+void TimeTest::TestMonotonicity() {
+  embb_time_t first;
+  embb_time_t second;
+  int status1 = embb_time_in(&first, embb_duration_zero());
+  int status2 = embb_time_in(&second, embb_duration_zero());
+  PT_EXPECT_EQ(status1, EMBB_SUCCESS);
+  PT_EXPECT_EQ(status2, EMBB_SUCCESS);
+  unsigned long long first_abs = first.seconds * 1000 + first.nanoseconds / 1000000;
+  unsigned long long second_abs = second.seconds * 1000 + second.nanoseconds / 1000000;
+  PT_EXPECT_GE(second_abs, first_abs);
+}
+
 } // namespace test
 } // namespace base
 } // namespace embb

base_c/test/time_test.h

@@ -42,9 +42,14 @@ class TimeTest : public partest::TestCase {
 
  private:
   /**
-   * Tests time in duration method.
+   * Tests time-in-duration method.
    */
   void TestTimeInDuration();
+
+  /**
+   * Tests that succeedingly taken times are monotonously increasing.
+   */
+  void TestMonotonicity();
 };
 
 } // namespace test