/rtmp/date_era.diff

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
new file mode 100644
index c03dd6c..282bb0d
*** a/doc/src/sgml/func.sgml
--- b/doc/src/sgml/func.sgml
*************** SELECT SUBSTRING('XY1234Z', 'Y*?([0-9]{1
*** 5550,5555 ****
--- 5550,5564 ----
  
       <listitem>
        <para>
+        If the year format specification is less than four digits, e.g.
+        <literal>YYY</>, and the supplied year is less than four digits,
+        the year will be adjusted to be nearest to year 2020, e.g.
+        <literal>95</> becomes 1995.
+       </para>
+      </listitem>
+ 
+      <listitem>
+       <para>
         The <literal>YYYY</literal> conversion from string to <type>timestamp</type> or
         <type>date</type> has a restriction when processing years with more than 4 digits. You must
         use some non-digit character or template after <literal>YYYY</literal>,
diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
new file mode 100644
index 726a1f4..1a3ec1c
*** a/src/backend/utils/adt/formatting.c
--- b/src/backend/utils/adt/formatting.c
*************** static void dump_node(FormatNode *node, 
*** 964,969 ****
--- 964,970 ----
  
  static char *get_th(char *num, int type);
  static char *str_numth(char *dest, char *num, int type);
+ static int	add_era_to_partial_year(int year);
  static int	strspace_len(char *str);
  static int	strdigits_len(char *str);
  static void from_char_set_mode(TmFromChar *tmfc, const FromCharDateMode mode);
*************** is_next_separator(FormatNode *n)
*** 1968,1973 ****
--- 1969,1999 ----
  	return TRUE;				/* some non-digit input (separator) */
  }
  
+ 
+ static int
+ add_era_to_partial_year(int year)
+ {
+ 	/*
+ 	 * Adjust all dates toward 2020;  this is effectively what happens
+ 	 * when we assume '70' is 1970 and '69' is 2069.
+ 	 */
+ 	/* Force 0-69 into the 2000's */
+ 	if (year < 70)
+ 		return year + 2000;
+ 	/* Force 70-99 into the 1900's */
+ 	else if (year >= 70 && year < 100)
+ 		return year + 1900;
+ 	/* Force 100-519 into the 2000's */
+ 	else if (year >= 100 && year < 519)
+ 		return year + 2000;
+ 	/* Force 520-999 into the 1000's */
+ 	else if (year >= 520 && year < 1000)
+ 		return year + 1000;
+ 	else
+ 		return year;
+ }
+ 
+ 
  static int
  strspace_len(char *str)
  {
*************** DCH_from_char(FormatNode *node, char *in
*** 2930,2972 ****
  				break;
  			case DCH_YYY:
  			case DCH_IYY:
! 				from_char_parse_int(&out->year, &s, n);
  				out->yysz = 3;
- 
- 				/*
- 				 * 3-digit year: '100' ... '999' = 1100 ... 1999 '000' ...
- 				 * '099' = 2000 ... 2099
- 				 */
- 				if (out->year >= 100)
- 					out->year += 1000;
- 				else
- 					out->year += 2000;
  				s += SKIP_THth(n->suffix);
  				break;
  			case DCH_YY:
  			case DCH_IY:
! 				from_char_parse_int(&out->year, &s, n);
  				out->yysz = 2;
- 
- 				/*
- 				 * 2-digit year: '00' ... '69'	= 2000 ... 2069 '70' ... '99'
- 				 * = 1970 ... 1999
- 				 */
- 				if (out->year < 70)
- 					out->year += 2000;
- 				else
- 					out->year += 1900;
  				s += SKIP_THth(n->suffix);
  				break;
  			case DCH_Y:
  			case DCH_I:
! 				from_char_parse_int(&out->year, &s, n);
  				out->yysz = 1;
- 
- 				/*
- 				 * 1-digit year: always +2000
- 				 */
- 				out->year += 2000;
  				s += SKIP_THth(n->suffix);
  				break;
  			case DCH_RM:
--- 2956,2978 ----
  				break;
  			case DCH_YYY:
  			case DCH_IYY:
! 				if (from_char_parse_int(&out->year, &s, n) < 4)
! 					out->year = add_era_to_partial_year(out->year);
  				out->yysz = 3;
  				s += SKIP_THth(n->suffix);
  				break;
  			case DCH_YY:
  			case DCH_IY:
! 				if (from_char_parse_int(&out->year, &s, n) < 4)
! 					out->year = add_era_to_partial_year(out->year);
  				out->yysz = 2;
  				s += SKIP_THth(n->suffix);
  				break;
  			case DCH_Y:
  			case DCH_I:
! 				if (from_char_parse_int(&out->year, &s, n) < 4)
! 					out->year = add_era_to_partial_year(out->year);
  				out->yysz = 1;
  				s += SKIP_THth(n->suffix);
  				break;
  			case DCH_RM: