[develop] allow for scalar timeDelta multiplication up to 29 days.

examples/example_hl.f90

@@ -94,6 +94,11 @@ PROGRAM example
   td = t_timedelta("PT1H")
   td = td*0.5_c_double
   WRITE (0,*) "  PT1H * 0.5 = ", td%toString()
+
+  td = t_timedelta("PT1H")
+  td = td*25
+  WRITE (0,*) "  PT1H * 25 = ", td%toString()
+
   ! Cray bug? Doesn't seem to recognize OPERATOR(*)
 #ifndef _CRAYFTN
   td = t_timedelta("PT1H")

src/mtime_timedelta.c

@@ -1774,6 +1774,10 @@ moduloTimeDeltaFromDateTime(struct _datetime* start_dt, struct _timedelta* times
 struct _timedelta*
 elementwiseScalarMultiplyTimeDelta(struct _timedelta* base_td, int64_t lambda, struct _timedelta* scaled_td)
 {
+  /* scalar multiplication is well-defined/implmented for
+     days<=MAX_DAYS_ALLOWED. */
+  const int MAX_DAYS_ALLOWED = 29;
+
   if ((base_td != NULL) && (scaled_td != NULL) )
     {
       /* Scalar multiplication not supported for TimeDeltas consisting of day/month/year. */
@@ -1793,6 +1797,9 @@ elementwiseScalarMultiplyTimeDelta(struct _timedelta* base_td, int64_t lambda, s
       if (lambda < 0)
         lambda *= -1;
 
+      scaled_td->day    = 0;
+      scaled_td->month  = 0;
+      scaled_td->year   = 0;
 
       /* Multiply each element by scalar. */
 
@@ -1818,17 +1825,18 @@ elementwiseScalarMultiplyTimeDelta(struct _timedelta* base_td, int64_t lambda, s
         }
 
       scaled_td->hour += (int) lambda*base_td->hour;
-
-     /* Scalar multiplication can not give a value in excess of 24 hours. */
-     if ( scaled_td->hour >= NO_OF_HOURS_IN_A_DAY )
-       {
-         /* ERROR: Return on NULL. */
-         return NULL;
-       }
-
-      scaled_td->day    = 0;
-      scaled_td->month  = 0;
-      scaled_td->year   = 0;
+      while ( scaled_td->hour >= NO_OF_HOURS_IN_A_DAY )
+        {
+          scaled_td->hour -= NO_OF_HOURS_IN_A_DAY;
+          scaled_td->day += 1;
+          /* scalar multiplication is well-defined/implemented for
+             days<=MAX_DAYS_ALLOWED. */
+          if ( scaled_td->day > MAX_DAYS_ALLOWED )
+            {
+              /* ERROR: Return on NULL. */
+              return NULL;
+            }
+        }
 
       return scaled_td;
 
@@ -1864,6 +1872,10 @@ elementwiseScalarMultiplyTimeDelta(struct _timedelta* base_td, int64_t lambda, s
 struct _timedelta*
 elementwiseScalarMultiplyTimeDeltaDP(struct _timedelta* base_td, double lambda, struct _timedelta* scaled_td)
 {
+  /* scalar multiplication is well-defined/implmented for
+     days<=MAX_DAYS_ALLOWED. */
+  const int MAX_DAYS_ALLOWED = 29;
+
   if ((base_td != NULL) && (scaled_td != NULL) )
     {
       /* Scalar multiplication not supported for TimeDeltas consisting of day/month/year. */
@@ -1880,24 +1892,34 @@ elementwiseScalarMultiplyTimeDeltaDP(struct _timedelta* base_td, double lambda,
       if (lambda < 0.)
         lambda *= -1.;
 
+      scaled_td->day    = 0;
+      scaled_td->month  = 0;
+      scaled_td->year   = 0;
+
       /* Multiply each element by scalar. */
 
       scaled_td->hour = (int) lambda*base_td->hour;
-      /* Scalar multiplication can not give a value in excess of 24 hours. */
-      if ( scaled_td->hour >= NO_OF_HOURS_IN_A_DAY )
-        {
-          /* ERROR: Return on NULL. */
-          return NULL;
-        }
+
       double remainder_minutes = 60.*(lambda*base_td->hour - scaled_td->hour);
       scaled_td->minute = (int) (lambda*base_td->minute + remainder_minutes);
       double remainder_seconds = 60.*(lambda*base_td->minute + remainder_minutes - scaled_td->minute);
       scaled_td->second += (int) (lambda*base_td->second + remainder_seconds);
       double remainder_ms      = 1000.*((lambda*base_td->second + remainder_seconds) - scaled_td->second);
       scaled_td->ms = (int) (lambda*base_td->ms + remainder_ms);
-      scaled_td->day    = 0;
-      scaled_td->month  = 0;
-      scaled_td->year   = 0;
+
+      while ( scaled_td->hour >= NO_OF_HOURS_IN_A_DAY )
+        {
+          scaled_td->hour -= NO_OF_HOURS_IN_A_DAY;
+          scaled_td->day  += 1;
+          /* scalar multiplication is well-defined/implemented for
+             days<=MAX_DAYS_ALLOWED. */
+          if ( scaled_td->day > MAX_DAYS_ALLOWED )
+            {
+              /* ERROR: Return on NULL. */
+              return NULL;
+            }
+        }
+
       return scaled_td;
     }
   else