Features added:

* Wrote max(date) and min(date) aggregates
* Wrote operator "-" for date; date - date yields number of days
  difference
* Wrote operator+(date,int) and operator-(date,int); the int is the
  number of days.  Each operator returns a new date.


By: Tom Tromey <tromey@creche.cygnus.com>

src/backend/utils/adt/datetimes.c

@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *    $Header: /cvsroot/pgsql/src/backend/utils/adt/Attic/datetimes.c,v 1.6 1996/11/10 03:03:10 momjian Exp $
+ *    $Header: /cvsroot/pgsql/src/backend/utils/adt/Attic/datetimes.c,v 1.7 1996/11/14 21:38:58 scrappy Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -224,6 +224,104 @@ date_cmp(int4 dateVal1, int4 dateVal2)
     return 0;
 }
 
+int4
+date_larger(int4 dateVal1, int4 dateVal2)
+{
+  return (date_gt (dateVal1, dateVal2) ? dateVal1 : dateVal2);
+}
+
+int4
+date_smaller(int4 dateVal1, int4 dateVal2)
+{
+  return (date_lt (dateVal1, dateVal2) ? dateVal1 : dateVal2);
+}
+
+/* Compute difference between two dates in days.  */
+int32
+date_mi(int4 dateVal1, int4 dateVal2)
+{
+  DateADT *date1, *date2;
+  int32 days = 0;
+  int i;
+
+  date1 = (DateADT *) &dateVal1;
+  date2 = (DateADT *) &dateVal2;
+
+  /* Sum number of days in each full year between date1 and date2.  */
+  for (i = date1->year + 1; i < date2->year; ++i)
+    days += isleap (i) ? 366 : 365;
+
+  /* Add in number of days in each full month from date1 to end of
+     year.  */
+  for (i = date1->month + 1; i <= 12; ++i)
+    days += day_tab[isleap (date1->year)][i - 1];
+
+  /* Add in number of days in each full month from start of year to
+     date2.  */
+  for (i = 1; i < date2->month; ++i)
+    days += day_tab[isleap (date2->year)][i - 1];
+
+  /* Add in number of days left in month for date1.  */
+  days += day_tab[isleap (date1->year)][date1->month - 1] - date1->day;
+
+  /* Add in day of month of date2.  */
+  days += date2->day;
+
+  return (days);
+}
+
+/* Add a number of days to a date, giving a new date.
+   Must handle both positive and negative numbers of days.  */
+int4
+date_pli(int4 dateVal, int32 days)
+{
+  DateADT *date1 = (DateADT *) &dateVal;
+  /* Use separate day variable because date1->day is a narrow type.  */
+  int32 day = date1->day + days;
+
+  if (days > 0)
+    {
+      /* Loop as long as day has wrapped around end of month.  */
+      while (day > day_tab[isleap (date1->year)][date1->month - 1])
+	{
+	  day -= day_tab[isleap (date1->year)][date1->month - 1];
+	  if (++date1->month > 12)
+	    {
+	      /* Month wrapped around.  */
+	      date1->month = 1;
+	      ++date1->year;
+	    }
+	}
+    }
+  else
+    {
+      /* Loop as long as day has wrapped around beginning of month.  */
+      while (day < 1)
+	{
+	  /* Decrement month first, because a negative day number
+	     should be held as relative to the previous month's end.  */
+	  if (--date1->month < 1)
+	    {
+	      /* Month wrapped around.  */
+	      date1->month = 12;
+	      --date1->year;
+	    }
+
+	  day += day_tab[isleap (date1->year)][date1->month - 1];
+	}
+    }
+  date1->day = day;
+
+  return (dateVal);
+}
+
+/* Subtract a number of days from a date, giving a new date.  */
+int4
+date_mii(int4 dateVal, int32 days)
+{
+  return (date_pli (dateVal, -days));
+}
+
 /*****************************************************************************
  *   Time ADT
  *****************************************************************************/

src/include/catalog/pg_aggregate.h

@@ -7,7 +7,7 @@
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: pg_aggregate.h,v 1.2 1996/10/31 09:47:04 scrappy Exp $
+ * $Id: pg_aggregate.h,v 1.3 1996/11/14 21:39:07 scrappy Exp $
  *
  * NOTES
  *    the genbki.sh script reads this file and generates .bki
@@ -101,11 +101,13 @@ DATA(insert OID = 0 ( max   PGUID int4larger   - -  23  23  0  23  _null_ _null_
 DATA(insert OID = 0 ( max   PGUID int2larger   - -  21  21  0  21  _null_ _null_ ));
 DATA(insert OID = 0 ( max PGUID float4larger - - 700  700 0  700  _null_ _null_ ));
 DATA(insert OID = 0 ( max PGUID float8larger - - 701  701 0  701  _null_ _null_ ));
+DATA(insert OID = 0 ( max PGUID date_larger  - - 1082 1082 0 1082 _null_ _null_ ));
 
 DATA(insert OID = 0 ( min   PGUID int4smaller   - -  23  23  0  23  _null_ _null_ ));
 DATA(insert OID = 0 ( min   PGUID int2smaller   - -  21  21  0  21    _null_ _null_ ));
 DATA(insert OID = 0 ( min PGUID float4smaller - - 700  700 0  700   _null_ _null_ ));
 DATA(insert OID = 0 ( min PGUID float8smaller - - 701  701 0  701  _null_ _null_ ));
+DATA(insert OID = 0 ( min PGUID date_smaller  - - 1082 1082 0 1082 _null_ _null_ ));
 
 DATA(insert OID = 0 ( count     PGUID - int4inc - 0 0 23 23  _null_ 0 ));
 

src/include/catalog/pg_operator.h

@@ -7,7 +7,7 @@
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: pg_operator.h,v 1.3 1996/11/13 20:50:58 scrappy Exp $
+ * $Id: pg_operator.h,v 1.4 1996/11/14 21:39:11 scrappy Exp $
  *
  * NOTES
  *    the genbki.sh script reads this file and generates .bki
@@ -389,6 +389,9 @@ DATA(insert OID = 1095 ( "<"       PGUID 0 b t f  1082  1082  16 1097 1098  0 0
 DATA(insert OID = 1096 ( "<="      PGUID 0 b t f  1082  1082  16 1098 1097  0 0 date_le intltsel intltjoinsel ));
 DATA(insert OID = 1097 ( ">"       PGUID 0 b t f  1082  1082  16 1095 1096  0 0 date_gt intltsel intltjoinsel ));
 DATA(insert OID = 1098 ( ">="      PGUID 0 b t f  1082  1082  16 1096 1065  0 0 date_ge intltsel intltjoinsel ));
+DATA(insert OID = 1099 ( "-"       PGUID 0 b t f  1082  1082  23 0 0 0 0 date_mi - - ));
+DATA(insert OID = 1100 ( "+"       PGUID 0 b t f  1082  23  1082 0 0 0 0 date_pli - - ));
+DATA(insert OID = 1101 ( "-"       PGUID 0 b t f    1082 23 1082 0 0 0 0 date_mii - - ));
 
 DATA(insert OID = 1108 ( "="       PGUID 0 b t t  1083  1083  16 1108 1109 1110 1110 time_eq eqsel eqjoinsel ));
 DATA(insert OID = 1109 ( "<>"      PGUID 0 b t f  1083  1083  16 1109 1108  0 0 time_ne neqsel neqjoinsel ));

src/include/catalog/pg_proc.h

@@ -6,7 +6,7 @@
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: pg_proc.h,v 1.6 1996/11/13 20:51:01 scrappy Exp $
+ * $Id: pg_proc.h,v 1.7 1996/11/14 21:39:14 scrappy Exp $
  *
  * NOTES
  *    The script catalog/genbki.sh reads this file and generates .bki
@@ -727,7 +727,11 @@ DATA(insert OID = 1089 (  date_gt          PGUID 11 f t f 2 f 16 "1082 1082" 100
 DATA(insert OID = 1090 (  date_ge          PGUID 11 f t f 2 f 16 "1082 1082" 100 0 0 100  foo bar ));
 DATA(insert OID = 1091 (  date_ne          PGUID 11 f t f 2 f 16 "1082 1082" 100 0 0 100  foo bar ));
 DATA(insert OID = 1092 (  date_cmp         PGUID 11 f t f 2 f 23 "1082 1082" 100 0 0 100  foo bar ));
-
+DATA(insert OID = 1093 (  date_larger      PGUID 11 f t f 2 f 1082 "1082 1082" 100 0 0 100  foo bar ));
+DATA(insert OID = 1094 (  date_smaller     PGUID 11 f t f 2 f 1082 "1082 1082" 100 0 0 100  foo bar ));
+DATA(insert OID = 1095 (  date_mi          PGUID 11 f t f 2 f 23 "1082 1082" 100 0 0 100  foo bar ));
+DATA(insert OID = 1096 (  date_pli         PGUID 11 f t f 2 f 1082 "1082 23" 100 0 0 100  foo bar ));
+DATA(insert OID = 1097 (  date_mii         PGUID 11 f t f 2 f 1082 "1082 23" 100 0 0 100  foo bar ));
 DATA(insert OID = 1099 (  time_in          PGUID 11 f t f 1 f 1083 "0" 100 0 0 100  foo bar ));
 
 /* OIDS 1100 - 1199 */