Ticket #4971: mythtv-0.21-wanttorun-hour-bigger-than-maxhour.2.patch

mythtv-0.21/programs/mythbackend/housekeeper.cpp

@@ -87 +87 @@
                      ((hour <= maxhour) || (hour >= minhour))) ||
                     ((hour >= minhour) && (hour <= maxhour)))
                 {
+                    // OK, we now know that the job is allowed to run. But we
+                    // want to randomize the start time.
+                    //
+                    // Allow the job run if
+                    // a) the caller has asked for deterministic behaviour, or
+                    // b) we have reached the last half hour of the window, or
+                    // c) we win a random draw with a probability of 1/N.
+                    //
+                    // N gets smaller the nearer we are to the end of the
+                    // window. The "(24 + ...) % 24" makes sure the calculation
+                    // is correct even for the case hour > minhour > maxhour.
                     int minute = now.time().minute();
                     if (exact ||
                         (hour == maxhour && minute > 30) ||
-                        ((random()%(((maxhour-hour)*12+(60-minute)/5 - 6) + 1)) == 0))
+                        ((random()%((((24+maxhour-hour)%24)*12+(60-minute)/5 - 6) + 1)) == 0))
                         runOK = true;
                 }
             }