Fix rounding problem in interval_div by using rint(), and improve

interval_mul function.

diff --git a/src/backend/utils/adt/timestamp.c b/src/backend/utils/adt/timestamp.c
index ac628453441132d268e5c311335d7eb12ccccace..85c5bda35f426abadf9d6369ea620e47af6f2e63 100644 (file)
--- a/src/backend/utils/adt/timestamp.c
+++ b/src/backend/utils/adt/timestamp.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *   $PostgreSQL: pgsql/src/backend/utils/adt/timestamp.c,v 1.145 2005/07/23 14:53:21 momjian Exp $
+ *   $PostgreSQL: pgsql/src/backend/utils/adt/timestamp.c,v 1.146 2005/07/24 04:37:07 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -2244,38 +2244,37 @@ interval_mi(PG_FUNCTION_ARGS)
 Datum
 interval_mul(PG_FUNCTION_ARGS)
 {
-   Interval   *span1 = PG_GETARG_INTERVAL_P(0);
+   Interval   *span = PG_GETARG_INTERVAL_P(0);
    float8      factor = PG_GETARG_FLOAT8(1);
+   double      month_remainder, day_remainder;
    Interval   *result;
 
-#ifdef HAVE_INT64_TIMESTAMP
-   int64       months;
-   int64       days;
-#else
-   double      months;
-   double      days;
-#endif
-
    result = (Interval *) palloc(sizeof(Interval));
 
-   months = span1->month * factor;
-   days = span1->day * factor;
+   result->month = span->month * factor;
+   result->day = span->day * factor;
+
+   /* Compute remainders */
+   month_remainder = span->month * factor - result->month;
+   day_remainder = span->day * factor - result->day;
+
+   /* Cascade fractions to lower units */
+   /* fractional months full days into days */
+   result->day += month_remainder * DAYS_PER_MONTH;
+   /* fractional months partial days into time */
+   day_remainder += (month_remainder * DAYS_PER_MONTH) -
+                    (int)(month_remainder * DAYS_PER_MONTH);
+
 #ifdef HAVE_INT64_TIMESTAMP
-   result->month = months;
-   result->day = days;
-   result->time = span1->time * factor;
-   result->time += (months - result->month) * INT64CONST(30) * USECS_PER_DAY;
-   result->time += (days - result->day) * INT64CONST(24) * USECS_PER_HOUR;
+   result->time = rint(span->time * factor +
+                   day_remainder * USECS_PER_DAY);
 #else
-   result->month = (int)months;
-   result->day = (int)days;
-   result->time = JROUND(span1->time * factor);
-   /* evaluate fractional months as 30 days */
-   result->time += JROUND((months - result->month) * DAYS_PER_MONTH * SECS_PER_DAY);
-   /* evaluate fractional days as 24 hours */
-   result->time += JROUND((days - result->day) * HOURS_PER_DAY * SECS_PER_HOUR);
+   result->time = JROUND(span->time * factor +
+                   day_remainder * SECS_PER_DAY);
 #endif
 
+   result = DatumGetIntervalP(DirectFunctionCall1(interval_justify_hours,
+                                               IntervalPGetDatum(result)));
    PG_RETURN_INTERVAL_P(result);
 }
 
@@ -2284,9 +2283,9 @@ mul_d_interval(PG_FUNCTION_ARGS)
 {
    /* Args are float8 and Interval *, but leave them as generic Datum */
    Datum       factor = PG_GETARG_DATUM(0);
-   Datum       span1 = PG_GETARG_DATUM(1);
+   Datum       span = PG_GETARG_DATUM(1);
 
-   return DirectFunctionCall2(interval_mul, span1, factor);
+   return DirectFunctionCall2(interval_mul, span, factor);
 }
 
 Datum
@@ -2316,10 +2315,11 @@ interval_div(PG_FUNCTION_ARGS)
    /* fractional months full days into days */
    result->day += month_remainder * DAYS_PER_MONTH;
    /* fractional months partial days into time */
-   day_remainder += (month_remainder * DAYS_PER_MONTH) - (int)(month_remainder * DAYS_PER_MONTH);
+   day_remainder += (month_remainder * DAYS_PER_MONTH) -
+                    (int)(month_remainder * DAYS_PER_MONTH);
 
 #ifdef HAVE_INT64_TIMESTAMP
-   result->time += day_remainder * USECS_PER_DAY;
+   result->time += rint(day_remainder * USECS_PER_DAY);
 #else
    result->time += day_remainder * SECS_PER_DAY;
    result->time = JROUND(result->time);