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);