Support "of", "tzh", and "tzm" format codes.

The upper case versions "OF", "TZH", and "TZM" are already supported,
and all other format codes that are supported in upper case are also
supported in lower case, so we should support these as well for
consistency.

Nitin Jadhav, with a tiny cosmetic change by me. Reviewed by Suraj
Kharage and David Zhang.

Discussion: http://postgr.es/m/CAMm1aWZ-oZyKd75+8D=VJ0sAoSwtdXWLP-MAWD4D8R1Dgandzw@mail.gmail.com

Author: robertmhaas

src/backend/utils/adt/formatting.c

@@ -702,13 +702,16 @@ typedef enum
 	DCH_month,
 	DCH_mon,
 	DCH_ms,
+	DCH_of,
 	DCH_p_m,
 	DCH_pm,
 	DCH_q,
 	DCH_rm,
 	DCH_sssss,
 	DCH_ssss,
 	DCH_ss,
+	DCH_tzh,
+	DCH_tzm,
 	DCH_tz,
 	DCH_us,
 	DCH_ww,
@@ -865,14 +868,17 @@ static const KeyWord DCH_keywords[] = {
 	{"month", 5, DCH_month, false, FROM_CHAR_DATE_GREGORIAN},
 	{"mon", 3, DCH_mon, false, FROM_CHAR_DATE_GREGORIAN},
 	{"ms", 2, DCH_MS, true, FROM_CHAR_DATE_NONE},
+	{"of", 2, DCH_OF, false, FROM_CHAR_DATE_NONE},  /* o */
 	{"p.m.", 4, DCH_p_m, false, FROM_CHAR_DATE_NONE},	/* p */
 	{"pm", 2, DCH_pm, false, FROM_CHAR_DATE_NONE},
 	{"q", 1, DCH_Q, true, FROM_CHAR_DATE_NONE}, /* q */
 	{"rm", 2, DCH_rm, false, FROM_CHAR_DATE_GREGORIAN}, /* r */
 	{"sssss", 5, DCH_SSSS, true, FROM_CHAR_DATE_NONE},	/* s */
 	{"ssss", 4, DCH_SSSS, true, FROM_CHAR_DATE_NONE},
 	{"ss", 2, DCH_SS, true, FROM_CHAR_DATE_NONE},
-	{"tz", 2, DCH_tz, false, FROM_CHAR_DATE_NONE},	/* t */
+	{"tzh", 3, DCH_TZH, false, FROM_CHAR_DATE_NONE},    /* t */
+	{"tzm", 3, DCH_TZM, true, FROM_CHAR_DATE_NONE},
+	{"tz", 2, DCH_tz, false, FROM_CHAR_DATE_NONE},
 	{"us", 2, DCH_US, true, FROM_CHAR_DATE_NONE},	/* u */
 	{"ww", 2, DCH_WW, true, FROM_CHAR_DATE_GREGORIAN},	/* w */
 	{"w", 1, DCH_W, true, FROM_CHAR_DATE_GREGORIAN},
@@ -954,7 +960,7 @@ static const int DCH_index[KeyWord_INDEX_SIZE] = {
 	DCH_P_M, DCH_Q, DCH_RM, DCH_SSSSS, DCH_TZH, DCH_US, -1, DCH_WW, -1, DCH_Y_YYY,
 	-1, -1, -1, -1, -1, -1, -1, DCH_a_d, DCH_b_c, DCH_cc,
 	DCH_day, -1, DCH_ff1, -1, DCH_hh24, DCH_iddd, DCH_j, -1, -1, DCH_mi,
-	-1, -1, DCH_p_m, DCH_q, DCH_rm, DCH_sssss, DCH_tz, DCH_us, -1, DCH_ww,
+	-1, DCH_of, DCH_p_m, DCH_q, DCH_rm, DCH_sssss, DCH_tzh, DCH_us, -1, DCH_ww,
 	-1, DCH_y_yyy, -1, -1, -1, -1
 
 	/*---- chars over 126 are skipped ----*/

src/test/regress/expected/timestamptz.out

@@ -2166,6 +2166,71 @@ SELECT to_char(now(), 'OF') as "OF", to_char(now(), 'TZH:TZM') as "TZH:TZM";
  -04:15 | -04:15
 (1 row)
 
+RESET timezone;
+-- Check of, tzh, tzm with various zone offsets.
+SET timezone = '00:00';
+SELECT to_char(now(), 'of') as "Of", to_char(now(), 'tzh:tzm') as "tzh:tzm";
+ Of  | tzh:tzm 
+-----+---------
+ +00 | +00:00
+(1 row)
+
+SET timezone = '+02:00';
+SELECT to_char(now(), 'of') as "of", to_char(now(), 'tzh:tzm') as "tzh:tzm";
+ of  | tzh:tzm 
+-----+---------
+ -02 | -02:00
+(1 row)
+
+SET timezone = '-13:00';
+SELECT to_char(now(), 'of') as "of", to_char(now(), 'tzh:tzm') as "tzh:tzm";
+ of  | tzh:tzm 
+-----+---------
+ +13 | +13:00
+(1 row)
+
+SET timezone = '-00:30';
+SELECT to_char(now(), 'of') as "of", to_char(now(), 'tzh:tzm') as "tzh:tzm";
+   of   | tzh:tzm 
+--------+---------
+ +00:30 | +00:30
+(1 row)
+
+SET timezone = '00:30';
+SELECT to_char(now(), 'of') as "of", to_char(now(), 'tzh:tzm') as "tzh:tzm";
+   of   | tzh:tzm 
+--------+---------
+ -00:30 | -00:30
+(1 row)
+
+SET timezone = '-04:30';
+SELECT to_char(now(), 'of') as "of", to_char(now(), 'tzh:tzm') as "tzh:tzm";
+   of   | tzh:tzm 
+--------+---------
+ +04:30 | +04:30
+(1 row)
+
+SET timezone = '04:30';
+SELECT to_char(now(), 'of') as "of", to_char(now(), 'tzh:tzm') as "tzh:tzm";
+   of   | tzh:tzm 
+--------+---------
+ -04:30 | -04:30
+(1 row)
+
+SET timezone = '-04:15';
+SELECT to_char(now(), 'of') as "of", to_char(now(), 'tzh:tzm') as "tzh:tzm";
+   of   | tzh:tzm 
+--------+---------
+ +04:15 | +04:15
+(1 row)
+
+SET timezone = '04:15';
+SELECT to_char(now(), 'of') as "of", to_char(now(), 'tzh:tzm') as "tzh:tzm";
+   of   | tzh:tzm 
+--------+---------
+ -04:15 | -04:15
+(1 row)
+
 RESET timezone;
 CREATE TABLE TIMESTAMPTZ_TST (a int , b timestamptz);
 -- Test year field value with len > 4

src/test/regress/sql/timestamptz.sql

@@ -360,6 +360,28 @@ SET timezone = '04:15';
 SELECT to_char(now(), 'OF') as "OF", to_char(now(), 'TZH:TZM') as "TZH:TZM";
 RESET timezone;
 
+-- Check of, tzh, tzm with various zone offsets.
+SET timezone = '00:00';
+SELECT to_char(now(), 'of') as "Of", to_char(now(), 'tzh:tzm') as "tzh:tzm";
+SET timezone = '+02:00';
+SELECT to_char(now(), 'of') as "of", to_char(now(), 'tzh:tzm') as "tzh:tzm";
+SET timezone = '-13:00';
+SELECT to_char(now(), 'of') as "of", to_char(now(), 'tzh:tzm') as "tzh:tzm";
+SET timezone = '-00:30';
+SELECT to_char(now(), 'of') as "of", to_char(now(), 'tzh:tzm') as "tzh:tzm";
+SET timezone = '00:30';
+SELECT to_char(now(), 'of') as "of", to_char(now(), 'tzh:tzm') as "tzh:tzm";
+SET timezone = '-04:30';
+SELECT to_char(now(), 'of') as "of", to_char(now(), 'tzh:tzm') as "tzh:tzm";
+SET timezone = '04:30';
+SELECT to_char(now(), 'of') as "of", to_char(now(), 'tzh:tzm') as "tzh:tzm";
+SET timezone = '-04:15';
+SELECT to_char(now(), 'of') as "of", to_char(now(), 'tzh:tzm') as "tzh:tzm";
+SET timezone = '04:15';
+SELECT to_char(now(), 'of') as "of", to_char(now(), 'tzh:tzm') as "tzh:tzm";
+RESET timezone;
+
+
 CREATE TABLE TIMESTAMPTZ_TST (a int , b timestamptz);
 
 -- Test year field value with len > 4