Tom Lane wrote:
{
int32 arg1 = PG_GETARG_INT32(0);
int32 arg2 = PG_GETARG_INT32(1);
+ int32 result;
! result = arg1 * arg2;
! /*
! * Overflow check. We basically check to see if result / arg2 gives
! * arg1 again. There are two cases where this fails: arg2 = 0 (which
! * cannot overflow) and arg1 = INT_MIN, arg2 = -1 (where the division
! * itself will overflow and thus incorrectly match).
! *
! * Since the division is likely much more expensive than the actual
! * multiplication, we'd like to skip it where possible. The best
! * bang for the buck seems to be to check whether both inputs are in
! * the int16 range; if so, no overflow is possible.
! */
! if (!(arg1 >= (int32) SHRT_MIN && arg1 <= (int32) SHRT_MAX &&
! arg2 >= (int32) SHRT_MIN && arg2 <= (int32) SHRT_MAX) &&
! arg2 != 0 &&
! (result/arg2 != arg1 || (arg2 == -1 && arg1 < 0 && result < 0)))
! ereport(ERROR,
! (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
! errmsg("integer out of range")));
! PG_RETURN_INT32(result);
}
May be is a good idea postpone the division as second "OR" argument in order to hope to avoid it.
Regards Gaetano Mendola
---------------------------(end of broadcast)--------------------------- TIP 4: Don't 'kill -9' the postmaster
