Hi,

 the to_char() source code is large, here are regression tests for
numeric/timestamp/int8 part. It is probably enough test for formatting
code in the formatting.c module. The others (float4/float8/int4) types
share this formatting code and eventual bugs for these types aren't
few probable.

 Patch fix timestamp_to_char() for infinity/invalid timestamp too.


                                                Karel

src/backend/utils/adt/formatting.c

 /* -----------------------------------------------------------------------
  * formatting.c
  *
- * $Header: /cvsroot/pgsql/src/backend/utils/adt/formatting.c,v 1.4 2000/02/16 17:24:48 thomas Exp $
+ * $Header: /cvsroot/pgsql/src/backend/utils/adt/formatting.c,v 1.5 2000/03/08 01:34:36 momjian Exp $
  *
  *
  *   Portions Copyright (c) 1999-2000, PostgreSQL, Inc
@@ -630,7 +630,7 @@ static FormatNode *NUM_cache( int len, char *CacheStr, FormatNode *CacheFormat,
 static char *int_to_roman(int number);
 static void NUM_prepare_locale(NUMProc *Np);
 static char *get_last_relevant_decnum(char *num);
-static void NUM_numpart_from_char(NUMProc *Np, int id); 
+static void NUM_numpart_from_char(NUMProc *Np, int id, int plen); 
 static void NUM_numpart_to_char(NUMProc *Np, int id); 
 static char *NUM_processor (FormatNode *node, NUMDesc *Num, char *inout, char *number, 
 					int plen, int sign, int type);
@@ -1798,14 +1798,14 @@ timestamp_to_char(Timestamp *dt, text *fmt)
 	char			*str;
 	double          	fsec;
 	char       		*tzn;
-	int			len=0, tz;
+	int			len=0, tz, x=0;
 
 	if ((!PointerIsValid(dt)) || (!PointerIsValid(fmt)))
 		return NULL;
 	
 	len 	= VARSIZE(fmt) - VARHDRSZ; 
 	
-	if (!len) 
+	if ((!len) || (TIMESTAMP_NOT_FINITE(*dt))) 
 		return textin("");
 
 	tm->tm_sec	=0;	tm->tm_year	=0;
@@ -1814,16 +1814,19 @@ timestamp_to_char(Timestamp *dt, text *fmt)
 	tm->tm_mday	=1;	tm->tm_isdst	=0;
 	tm->tm_mon	=1;
 
-	if (TIMESTAMP_IS_EPOCH(*dt))
-	{
-		timestamp2tm(SetTimestamp(*dt), NULL, tm, &fsec, NULL);
+	if (TIMESTAMP_IS_EPOCH(*dt)) {
+		x = timestamp2tm(SetTimestamp(*dt), NULL, tm, &fsec, NULL);
+		
 	} else if (TIMESTAMP_IS_CURRENT(*dt)) {
-		timestamp2tm(SetTimestamp(*dt), &tz, tm, &fsec, &tzn);
+		x = timestamp2tm(SetTimestamp(*dt), &tz, tm, &fsec, &tzn);
+			
 	} else {
-		if (timestamp2tm(*dt, &tz, tm, &fsec, &tzn) != 0)
-			elog(ERROR, "to_char(): Unable to convert timestamp to tm");
+		x = timestamp2tm(*dt, &tz, tm, &fsec, &tzn);
 	}
 
+	if (x!=0)
+		elog(ERROR, "to_char(): Unable to convert timestamp to tm");
+
 	tm->tm_wday = (date2j(tm->tm_year, tm->tm_mon, tm->tm_mday) + 1) % 7; 
 	tm->tm_yday = date2j(tm->tm_year, tm->tm_mon, tm->tm_mday) - date2j(tm->tm_year, 1,1) +1;
 
@@ -2330,7 +2333,7 @@ get_last_relevant_decnum(char *num)
 	char	*result, 
 		*p = strchr(num, '.');
 	
-	elog(NOTICE, "CALL: get_last_relevant_decnum()");
+	/*elog(NOTICE, "CALL: get_last_relevant_decnum()");*/
 	
 	if (!p)	
 		p = num;
@@ -2349,16 +2352,21 @@ get_last_relevant_decnum(char *num)
  * ----------
  */
 static void
-NUM_numpart_from_char(NUMProc *Np, int id) 
+NUM_numpart_from_char(NUMProc *Np, int id, int plen) 
 {
 	
 #ifdef DEBUG_TO_FROM_CHAR
 	elog(DEBUG_elog_output, " --- scan start --- ");
 #endif
 
+#define OVERLOAD_TEST	(Np->inout_p >= Np->inout + plen)
+
 	if (*Np->inout_p == ' ') 
 		Np->inout_p++;		
 
+	if (OVERLOAD_TEST)
+		return;
+
 	/* ----------
 	 * read sign
 	 * ----------
@@ -2413,6 +2421,9 @@ NUM_numpart_from_char(NUMProc *Np, int id)
 		} 		
 	}
 	
+	if (OVERLOAD_TEST)
+		return;
+	
 	/* ----------
 	 * read digit
 	 * ----------
@@ -2430,7 +2441,7 @@ NUM_numpart_from_char(NUMProc *Np, int id)
 
 #ifdef DEBUG_TO_FROM_CHAR	
 		elog(DEBUG_elog_output, "Read digit (%c).", *Np->inout_p);
-#endif	
+#endif		
 	
 	/* ----------
 	 * read decimal point
@@ -2821,7 +2832,7 @@ NUM_processor (FormatNode *node, NUMDesc *Num, char *inout, char *number,
 			 * Check non-string inout end
 			 * ----------
 			 */
-			if (Np->inout_p == Np->inout + plen) 
+			if (Np->inout_p >= Np->inout + plen) 
 				break;
 		}
 		
@@ -2847,7 +2858,7 @@ NUM_processor (FormatNode *node, NUMDesc *Num, char *inout, char *number,
 					NUM_numpart_to_char(Np, n->key->id);
 					continue;	/* for() */
 				} else {
-					NUM_numpart_from_char(Np, n->key->id);
+					NUM_numpart_from_char(Np, n->key->id, plen);
 					break;		/* switch() case: */
 				}
 			

src/test/regress/expected/int8.out

@@ -117,3 +117,179 @@ SELECT '' AS five, q1 * 2 AS "twice int4" FROM INT8_TBL;
       | 9135780246913578
 (5 rows)
 
+-- TO_CHAR()
+--
+SELECT '' AS to_char_1, to_char(q1, '9G999G999G999G999G999'), to_char(q2, '9,999,999,999,999,999') 
+	FROM INT8_TBL;
+ to_char_1 |        to_char         |        to_char         
+-----------+------------------------+------------------------
+           |                    123 |                    456
+           |                    123 |  4,567,890,123,456,789
+           |  4,567,890,123,456,789 |                    123
+           |  4,567,890,123,456,789 |  4,567,890,123,456,789
+           |  4,567,890,123,456,789 | -4,567,890,123,456,789
+(5 rows)
+
+SELECT '' AS to_char_2, to_char(q1, '9G999G999G999G999G999D999G999'), to_char(q2, '9,999,999,999,999,999.999,999') 
+	FROM INT8_TBL;	
+ to_char_2 |            to_char             |            to_char             
+-----------+--------------------------------+--------------------------------
+           |                    123.000,000 |                    456.000,000
+           |                    123.000,000 |  4,567,890,123,456,789.000,000
+           |  4,567,890,123,456,789.000,000 |                    123.000,000
+           |  4,567,890,123,456,789.000,000 |  4,567,890,123,456,789.000,000
+           |  4,567,890,123,456,789.000,000 | -4,567,890,123,456,789.000,000
+(5 rows)
+
+SELECT '' AS to_char_3, to_char( (q1 * -1), '9999999999999999PR'), to_char( (q2 * -1), '9999999999999999.999PR') 
+	FROM INT8_TBL;
+ to_char_3 |      to_char       |        to_char         
+-----------+--------------------+------------------------
+           |              <123> |              <456.000>
+           |              <123> | <4567890123456789.000>
+           | <4567890123456789> |              <123.000>
+           | <4567890123456789> | <4567890123456789.000>
+           | <4567890123456789> |  4567890123456789.000
+(5 rows)
+
+SELECT '' AS to_char_4, to_char( (q1 * -1), '9999999999999999S'), to_char( (q2 * -1), 'S9999999999999999') 
+	FROM INT8_TBL;
+ to_char_4 |      to_char      |      to_char      
+-----------+-------------------+-------------------
+           |              123- |              -456
+           |              123- | -4567890123456789
+           | 4567890123456789- |              -123
+           | 4567890123456789- | -4567890123456789
+           | 4567890123456789- | +4567890123456789
+(5 rows)
+
+SELECT '' AS to_char_5,  to_char(q2, 'MI9999999999999999')     FROM INT8_TBL;	
+ to_char_5 |      to_char       
+-----------+--------------------
+           |                456
+           |   4567890123456789
+           |                123
+           |   4567890123456789
+           | -4567890123456789
+(5 rows)
+
+SELECT '' AS to_char_6,  to_char(q2, 'FMS9999999999999999')    FROM INT8_TBL;
+ to_char_6 |      to_char      
+-----------+-------------------
+           | +456
+           | +4567890123456789
+           | +123
+           | +4567890123456789
+           | -4567890123456789
+(5 rows)
+
+SELECT '' AS to_char_7,  to_char(q2, 'FM9999999999999999THPR') FROM INT8_TBL;
+ to_char_7 |      to_char       
+-----------+--------------------
+           | 456TH
+           | 4567890123456789TH
+           | 123RD
+           | 4567890123456789TH
+           | <4567890123456789>
+(5 rows)
+
+SELECT '' AS to_char_8,  to_char(q2, 'SG9999999999999999th')   FROM INT8_TBL;	
+ to_char_8 |       to_char       
+-----------+---------------------
+           | +             456th
+           | +4567890123456789th
+           | +             123rd
+           | +4567890123456789th
+           | -4567890123456789
+(5 rows)
+
+SELECT '' AS to_char_9,  to_char(q2, '0999999999999999')       FROM INT8_TBL;	
+ to_char_9 |      to_char      
+-----------+-------------------
+           |  0000000000000456
+           |  4567890123456789
+           |  0000000000000123
+           |  4567890123456789
+           | -4567890123456789
+(5 rows)
+
+SELECT '' AS to_char_10, to_char(q2, 'S0999999999999999')      FROM INT8_TBL;	
+ to_char_10 |      to_char      
+------------+-------------------
+            | +0000000000000456
+            | +4567890123456789
+            | +0000000000000123
+            | +4567890123456789
+            | -4567890123456789
+(5 rows)
+
+SELECT '' AS to_char_11, to_char(q2, 'FM0999999999999999')     FROM INT8_TBL;	
+ to_char_11 |      to_char      
+------------+-------------------
+            | 0000000000000456
+            | 4567890123456789
+            | 0000000000000123
+            | 4567890123456789
+            | -4567890123456789
+(5 rows)
+
+SELECT '' AS to_char_12, to_char(q2, 'FM9999999999999999.000') FROM INT8_TBL;
+ to_char_12 |        to_char        
+------------+-----------------------
+            | 456.000
+            | 4567890123456789.000
+            | 123.000
+            | 4567890123456789.000
+            | -4567890123456789.000
+(5 rows)
+
+SELECT '' AS to_char_13, to_char(q2, 'L9999999999999999.000')  FROM INT8_TBL;	
+ to_char_13 |        to_char         
+------------+------------------------
+            |                456.000
+            |   4567890123456789.000
+            |                123.000
+            |   4567890123456789.000
+            |  -4567890123456789.000
+(5 rows)
+
+SELECT '' AS to_char_14, to_char(q2, 'FM9999999999999999.999') FROM INT8_TBL;
+ to_char_14 |      to_char      
+------------+-------------------
+            | 456
+            | 4567890123456789
+            | 123
+            | 4567890123456789
+            | -4567890123456789
+(5 rows)
+
+SELECT '' AS to_char_15, to_char(q2, 'S 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 . 9 9 9') FROM INT8_TBL;
+ to_char_15 |                  to_char                  
+------------+-------------------------------------------
+            |                           +4 5 6 . 0 0 0 
+            | + 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 . 0 0 0
+            |                           +1 2 3 . 0 0 0 
+            | + 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 . 0 0 0
+            | - 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 . 0 0 0
+(5 rows)
+
+SELECT '' AS to_char_16, to_char(q2, '99999 text 9999 "9999" 999 "\\"text between quote marks\\"" 9999') FROM INT8_TBL;
+ to_char_16 |                          to_char                          
+------------+-----------------------------------------------------------
+            |       text      9999     "text between quote marks"   456
+            |  45678 text 9012 9999 345 "text between quote marks" 6789
+            |       text      9999     "text between quote marks"   123
+            |  45678 text 9012 9999 345 "text between quote marks" 6789
+            | -45678 text 9012 9999 345 "text between quote marks" 6789
+(5 rows)
+
+SELECT '' AS to_char_17, to_char(q2, '999999SG9999999999')     FROM INT8_TBL;
+ to_char_17 |      to_char      
+------------+-------------------
+            |       +       456
+            | 456789+0123456789
+            |       +       123
+            | 456789+0123456789
+            | 456789-0123456789
+(5 rows)
+

src/test/regress/sql/int8.sql

@@ -26,3 +26,31 @@ SELECT '' AS five, q1, int8(float8(q1)) AS "two coercions" FROM INT8_TBL;
 
 SELECT '' AS five, 2 * q1 AS "twice int4" FROM INT8_TBL;
 SELECT '' AS five, q1 * 2 AS "twice int4" FROM INT8_TBL;
+
+-- TO_CHAR()
+--
+SELECT '' AS to_char_1, to_char(q1, '9G999G999G999G999G999'), to_char(q2, '9,999,999,999,999,999') 
+	FROM INT8_TBL;
+
+SELECT '' AS to_char_2, to_char(q1, '9G999G999G999G999G999D999G999'), to_char(q2, '9,999,999,999,999,999.999,999') 
+	FROM INT8_TBL;	
+
+SELECT '' AS to_char_3, to_char( (q1 * -1), '9999999999999999PR'), to_char( (q2 * -1), '9999999999999999.999PR') 
+	FROM INT8_TBL;
+
+SELECT '' AS to_char_4, to_char( (q1 * -1), '9999999999999999S'), to_char( (q2 * -1), 'S9999999999999999') 
+	FROM INT8_TBL;
+
+SELECT '' AS to_char_5,  to_char(q2, 'MI9999999999999999')     FROM INT8_TBL;	
+SELECT '' AS to_char_6,  to_char(q2, 'FMS9999999999999999')    FROM INT8_TBL;
+SELECT '' AS to_char_7,  to_char(q2, 'FM9999999999999999THPR') FROM INT8_TBL;
+SELECT '' AS to_char_8,  to_char(q2, 'SG9999999999999999th')   FROM INT8_TBL;	
+SELECT '' AS to_char_9,  to_char(q2, '0999999999999999')       FROM INT8_TBL;	
+SELECT '' AS to_char_10, to_char(q2, 'S0999999999999999')      FROM INT8_TBL;	
+SELECT '' AS to_char_11, to_char(q2, 'FM0999999999999999')     FROM INT8_TBL;	
+SELECT '' AS to_char_12, to_char(q2, 'FM9999999999999999.000') FROM INT8_TBL;
+SELECT '' AS to_char_13, to_char(q2, 'L9999999999999999.000')  FROM INT8_TBL;	
+SELECT '' AS to_char_14, to_char(q2, 'FM9999999999999999.999') FROM INT8_TBL;
+SELECT '' AS to_char_15, to_char(q2, 'S 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 . 9 9 9') FROM INT8_TBL;
+SELECT '' AS to_char_16, to_char(q2, '99999 text 9999 "9999" 999 "\\"text between quote marks\\"" 9999') FROM INT8_TBL;
+SELECT '' AS to_char_17, to_char(q2, '999999SG9999999999')     FROM INT8_TBL;

src/test/regress/sql/numeric.sql

@@ -652,3 +652,52 @@ INSERT INTO fract_only VALUES (7, '0.00001');
 INSERT INTO fract_only VALUES (8, '0.00017');
 SELECT * FROM fract_only;
 DROP TABLE fract_only;
+
+-- TO_CHAR()
+--
+SELECT '' AS to_char_1, to_char(val, '9G999G999G999G999G999') 
+	FROM num_data;
+
+SELECT '' AS to_char_2, to_char(val, '9G999G999G999G999G999D999G999G999G999G999')
+	FROM num_data;	
+
+SELECT '' AS to_char_3, to_char(val, '9999999999999999.999999999999999PR')
+	FROM num_data;
+
+SELECT '' AS to_char_4, to_char(val, '9999999999999999.999999999999999S')
+	FROM num_data;
+
+SELECT '' AS to_char_5,  to_char(val, 'MI9999999999999999.999999999999999')     FROM num_data;	
+SELECT '' AS to_char_6,  to_char(val, 'FMS9999999999999999.999999999999999')    FROM num_data;
+SELECT '' AS to_char_7,  to_char(val, 'FM9999999999999999.999999999999999THPR') FROM num_data;
+SELECT '' AS to_char_8,  to_char(val, 'SG9999999999999999.999999999999999th')   FROM num_data;	
+SELECT '' AS to_char_9,  to_char(val, '0999999999999999.999999999999999')       FROM num_data;	
+SELECT '' AS to_char_10, to_char(val, 'S0999999999999999.999999999999999')      FROM num_data;	
+SELECT '' AS to_char_11, to_char(val, 'FM0999999999999999.999999999999999')     FROM num_data;	
+SELECT '' AS to_char_12, to_char(val, 'FM9999999999999999.099999999999999') 	FROM num_data;
+SELECT '' AS to_char_13, to_char(val, 'FM9999999999990999.990999999999999') 	FROM num_data;
+SELECT '' AS to_char_14, to_char(val, 'FM0999999999999999.999909999999999') 	FROM num_data;
+SELECT '' AS to_char_15, to_char(val, 'FM9999999990999999.099999999999999') 	FROM num_data;
+SELECT '' AS to_char_16, to_char(val, 'L9999999999999999.099999999999999')	FROM num_data;	
+SELECT '' AS to_char_17, to_char(val, 'FM9999999999999999.99999999999999')	FROM num_data;
+SELECT '' AS to_char_15, to_char(val, 'S 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 . 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9') FROM num_data;
+SELECT '' AS to_char_16, to_char(val, 'FMS 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 . 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9') FROM num_data;
+SELECT '' AS to_char_17, to_char(val, '99999 text 9999 "9999" 999 "\\"text between quote marks\\"" 9999') FROM num_data;
+SELECT '' AS to_char_18, to_char(val, '999999SG9999999999')			FROM num_data;
+SELECT '' AS to_char_19, to_char(val, 'FM9999999999999999.999999999999999')	FROM num_data;
+
+-- TO_NUMBER()
+--
+SELECT '' AS to_number_1,  to_number('-34,338,492', '99G999G999');
+SELECT '' AS to_number_2,  to_number('-34,338,492.654,878', '99G999G999D999G999');
+SELECT '' AS to_number_3,  to_number('<564646.654564>', '999999.999999PR');
+SELECT '' AS to_number_4,  to_number('0.00001-', '9.999999S');
+SELECT '' AS to_number_5,  to_number('5.01-', 'FM9.999999S');
+SELECT '' AS to_number_5,  to_number('5.01-', 'FM9.999999MI');
+SELECT '' AS to_number_7,  to_number('5 4 4 4 4 8 . 7 8', '9 9 9 9 9 9 . 9 9');
+SELECT '' AS to_number_8,  to_number('.01', 'FM9.99');
+SELECT '' AS to_number_9,  to_number('.0', '99999999.99999999');
+SELECT '' AS to_number_10, to_number('0', '99.99');
+SELECT '' AS to_number_11, to_number('.-01', 'S99.99');
+SELECT '' AS to_number_12, to_number('.01-', '99.99S');
+SELECT '' AS to_number_13, to_number(' . 0 1 -', ' 9 9 . 9 9 S');

src/test/regress/sql/timestamp.sql

@@ -167,3 +167,48 @@ SELECT '' AS fortynine, date_part( 'quarter', d1) AS quarter, date_part( 'msec',
    date_part( 'usec', d1) AS usec
    FROM TIMESTAMP_TBL WHERE d1 BETWEEN '1902-01-01' AND '2038-01-01';
 
+-- TO_CHAR()
+--
+SELECT '' AS to_char_1, to_char(d1, 'DAY Day day DY Dy dy MONTH Month month RM MON Mon mon') 
+   FROM TIMESTAMP_TBL;
+	
+SELECT '' AS to_char_2, to_char(d1, 'FMDAY FMDay FMday FMMONTH FMMonth FMmonth FMRM')
+   FROM TIMESTAMP_TBL;	
+
+SELECT '' AS to_char_3, to_char(d1, 'Y,YYY YYYY YYY YY Y CC Q MM WW DDD DD D J')
+   FROM TIMESTAMP_TBL;
+	
+SELECT '' AS to_char_4, to_char(d1, 'FMY,YYY FMYYYY FMYYY FMYY FMY FMCC FMQ FMMM FMWW FMDDD FMDD FMD FMJ') 
+   FROM TIMESTAMP_TBL;	
+	
+SELECT '' AS to_char_5, to_char(d1, 'HH HH12 HH24 MI SS SSSS') 
+   FROM TIMESTAMP_TBL;
+
+SELECT '' AS to_char_6, to_char(d1, '"HH:MI:SS is" HH:MI:SS "\\"text bettween quote marks\\""') 
+   FROM TIMESTAMP_TBL;		
+		
+SELECT '' AS to_char_7, to_char(d1, 'HH24--text--MI--text--SS')
+   FROM TIMESTAMP_TBL;		
+
+SELECT '' AS to_char_8, to_char(d1, 'YYYYTH YYYYth Jth') 
+   FROM TIMESTAMP_TBL;
+
+-- TO_TIMESTAMP()
+--
+SELECT '' AS to_timestamp_1, to_timestamp('0097/Feb/16 --> 08:14:30', 'YYYY/Mon/DD --> HH:MI:SS');
+	
+SELECT '' AS to_timestamp_2, to_timestamp('97/2/16 8:14:30', 'FMYYYY/FMMM/FMDD FMHH:FMMI:FMSS');
+
+SELECT '' AS to_timestamp_3, to_timestamp('1985 January 12', 'YYYY FMMonth DD');
+
+SELECT '' AS to_timestamp_4, to_timestamp('My birthday-> Year: 1976, Month: May, Day: 16',
+                    '"My birthday-> Year" YYYY, "Month:" FMMonth, "Day:" DD');
+
+SELECT '' AS to_timestamp_5, to_timestamp('1,582nd VIII 21', 'Y,YYYth FMRM DD');
+
+SELECT '' AS to_timestamp_6, to_timestamp('15 "text bettween quote marks" 98 54 45', 
+                    'HH "\\text bettween quote marks\\"" YY MI SS');
+    
+SELECT '' AS to_timestamp_7, to_timestamp('05121445482000', 'MMDDHHMISSYYYY');    
+
+SELECT '' AS to_timestamp_8, to_timestamp('2000January09Sunday', 'YYYYFMMonthDDFMDay');