src/timezone/strftime.c - hawq - Git at Google

 /*
  * Copyright (c) 1989 The Regents of the University of California.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms are permitted
  * provided that the above copyright notice and this paragraph are
  * duplicated in all such forms and that any documentation,
  * advertising materials, and other materials related to such
  * distribution and use acknowledge that the software was developed
  * by the University of California, Berkeley. The name of the
  * University may not be used to endorse or promote products derived
  * from this software without specific prior written permission.
  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  *
  * IDENTIFICATION
  *	  $PostgreSQL: pgsql/src/timezone/strftime.c,v 1.14 2009/06/11 14:49:15 momjian Exp $
  */

 #include "postgres.h"

 #include <fcntl.h>
 #include <locale.h>

 #include "private.h"
 #include "tzfile.h"


 struct lc_time_T
 {
 	const char *mon[MONSPERYEAR];
 	const char *month[MONSPERYEAR];
 	const char *wday[DAYSPERWEEK];
 	const char *weekday[DAYSPERWEEK];
 	const char *X_fmt;
 	const char *x_fmt;
 	const char *c_fmt;
 	const char *am;
 	const char *pm;
 	const char *date_fmt;
 };

 #define Locale	(&C_time_locale)

 static const struct lc_time_T C_time_locale = {
 	{
 		"Jan", "Feb", "Mar", "Apr", "May", "Jun",
 		"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
 	}, {
 		"January", "February", "March", "April", "May", "June",
 		"July", "August", "September", "October", "November", "December"
 	}, {
 		"Sun", "Mon", "Tue", "Wed",
 		"Thu", "Fri", "Sat"
 	}, {
 		"Sunday", "Monday", "Tuesday", "Wednesday",
 		"Thursday", "Friday", "Saturday"
 	},

 	/* X_fmt */
 	"%H:%M:%S",

 	/*
 	 * x_fmt
 	 *
 	 * C99 requires this format. Using just numbers (as here) makes Quakers
 	 * happier; it's also compatible with SVR4.
 	 */
 	"%m/%d/%y",

 	/*
 	 * c_fmt
 	 *
 	 * C99 requires this format. Previously this code used "%D %X", but we now
 	 * conform to C99. Note that "%a %b %d %H:%M:%S %Y" is used by Solaris
 	 * 2.3.
 	 */
 	"%a %b %e %T %Y",

 	/* am */
 	"AM",

 	/* pm */
 	"PM",

 	/* date_fmt */
 	"%a %b %e %H:%M:%S %Z %Y"
 };

 static char *_add(const char *, char *, const char *);
 static char *_conv(int, const char *, char *, const char *);
 static char *_fmt(const char *, const struct pg_tm *, char *,
 	 const char *, int *);
 static char * _yconv(const int, const int, const int, const int,
 	 char *, const char * const);

 #define IN_NONE 0
 #define IN_SOME 1
 #define IN_THIS 2
 #define IN_ALL	3


 size_t
 pg_strftime(char *s, size_t maxsize, const char *format,
 			const struct pg_tm * t)
 {
 	char	   *p;
 	int			warn;

 	warn = IN_NONE;
 	p = _fmt(((format == NULL) ? "%c" : format), t, s, s + maxsize, &warn);
 	if (p == s + maxsize)
 		return 0;
 	*p = '\0';
 	return p - s;
 }

 static char *
 _fmt(const char *format, const struct pg_tm * t, char *pt, const char *ptlim,
 	 int *warnp)
 {
 	for (; *format; ++format)
 	{
 		if (*format == '%')
 		{
 	label:
 			switch (*++format)
 			{
 				case '\0':
 					--format;
 					break;
 				case 'A':
 					pt = _add((t->tm_wday < 0 ||
 							   t->tm_wday >= DAYSPERWEEK) ?
 							  "?" : Locale->weekday[t->tm_wday],
 							  pt, ptlim);
 					continue;
 				case 'a':
 					pt = _add((t->tm_wday < 0 ||
 							   t->tm_wday >= DAYSPERWEEK) ?
 							  "?" : Locale->wday[t->tm_wday],
 							  pt, ptlim);
 					continue;
 				case 'B':
 					pt = _add((t->tm_mon < 0 ||
 							   t->tm_mon >= MONSPERYEAR) ?
 							  "?" : Locale->month[t->tm_mon],
 							  pt, ptlim);
 					continue;
 				case 'b':
 				case 'h':
 					pt = _add((t->tm_mon < 0 ||
 							   t->tm_mon >= MONSPERYEAR) ?
 							  "?" : Locale->mon[t->tm_mon],
 							  pt, ptlim);
 					continue;
 				case 'C':

 					/*
 					 * %C used to do a... _fmt("%a %b %e %X %Y", t);
 					 * ...whereas now POSIX 1003.2 calls for something
 					 * completely different. (ado, 1993-05-24)
 					 */
 					pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 0,
 								pt, ptlim);
 					continue;
 				case 'c':
 					{
 						int			warn2 = IN_SOME;

 						pt = _fmt(Locale->c_fmt, t, pt, ptlim, warnp);
 						if (warn2 == IN_ALL)
 							warn2 = IN_THIS;
 						if (warn2 > *warnp)
 							*warnp = warn2;
 					}
 					continue;
 				case 'D':
 					pt = _fmt("%m/%d/%y", t, pt, ptlim, warnp);
 					continue;
 				case 'd':
 					pt = _conv(t->tm_mday, "%02d", pt, ptlim);
 					continue;
 				case 'E':
 				case 'O':

 					/*
 					 * C99 locale modifiers. The sequences	%Ec %EC %Ex %EX
 					 * %Ey %EY	%Od %oe %OH %OI %Om %OM  %OS %Ou %OU %OV %Ow
 					 * %OW %Oy are supposed to provide alternate
 					 * representations.
 					 */
 					goto label;
 				case 'e':
 					pt = _conv(t->tm_mday, "%2d", pt, ptlim);
 					continue;
 				case 'F':
 					pt = _fmt("%Y-%m-%d", t, pt, ptlim, warnp);
 					continue;
 				case 'H':
 					pt = _conv(t->tm_hour, "%02d", pt, ptlim);
 					continue;
 				case 'I':
 					pt = _conv((t->tm_hour % 12) ?
 							   (t->tm_hour % 12) : 12,
 							   "%02d", pt, ptlim);
 					continue;
 				case 'j':
 					pt = _conv(t->tm_yday + 1, "%03d", pt, ptlim);
 					continue;
 				case 'k':

 					/*
 					 * This used to be...  _conv(t->tm_hour % 12 ? t->tm_hour
 					 * % 12 : 12, 2, ' '); ...and has been changed to the
 					 * below to match SunOS 4.1.1 and Arnold Robbins' strftime
 					 * version 3.0. That is, "%k" and "%l" have been swapped.
 					 * (ado, 1993-05-24)
 					 */
 					pt = _conv(t->tm_hour, "%2d", pt, ptlim);
 					continue;
 #ifdef KITCHEN_SINK
 				case 'K':

 					/*
 					 * * After all this time, still unclaimed!
 					 */
 					pt = _add("kitchen sink", pt, ptlim);
 					continue;
 #endif   /* defined KITCHEN_SINK */
 				case 'l':

 					/*
 					 * This used to be...  _conv(t->tm_hour, 2, ' '); ...and
 					 * has been changed to the below to match SunOS 4.1.1 and
 					 * Arnold Robbin's strftime version 3.0. That is, "%k" and
 					 * "%l" have been swapped. (ado, 1993-05-24)
 					 */
 					pt = _conv((t->tm_hour % 12) ?
 							   (t->tm_hour % 12) : 12,
 							   "%2d", pt, ptlim);
 					continue;
 				case 'M':
 					pt = _conv(t->tm_min, "%02d", pt, ptlim);
 					continue;
 				case 'm':
 					pt = _conv(t->tm_mon + 1, "%02d", pt, ptlim);
 					continue;
 				case 'n':
 					pt = _add("\n", pt, ptlim);
 					continue;
 				case 'p':
 					pt = _add((t->tm_hour >= (HOURSPERDAY / 2)) ?
 							  Locale->pm :
 							  Locale->am,
 							  pt, ptlim);
 					continue;
 				case 'R':
 					pt = _fmt("%H:%M", t, pt, ptlim, warnp);
 					continue;
 				case 'r':
 					pt = _fmt("%I:%M:%S %p", t, pt, ptlim, warnp);
 					continue;
 				case 'S':
 					pt = _conv(t->tm_sec, "%02d", pt, ptlim);
 					continue;
 				case 'T':
 					pt = _fmt("%H:%M:%S", t, pt, ptlim, warnp);
 					continue;
 				case 't':
 					pt = _add("\t", pt, ptlim);
 					continue;
 				case 'U':
 					pt = _conv((t->tm_yday + DAYSPERWEEK -
 								t->tm_wday) / DAYSPERWEEK,
 							   "%02d", pt, ptlim);
 					continue;
 				case 'u':

 					/*
 					 * From Arnold Robbins' strftime version 3.0: "ISO 8601:
 					 * Weekday as a decimal number [1 (Monday) - 7]" (ado,
 					 * 1993-05-24)
 					 */
 					pt = _conv((t->tm_wday == 0) ?
 							   DAYSPERWEEK : t->tm_wday,
 							   "%d", pt, ptlim);
 					continue;
 				case 'V':		/* ISO 8601 week number */
 				case 'G':		/* ISO 8601 year (four digits) */
 				case 'g':		/* ISO 8601 year (two digits) */
 /*
  * From Arnold Robbins' strftime version 3.0: "the week number of the
  * year (the first Monday as the first day of week 1) as a decimal number
  * (01-53)."
  * (ado, 1993-05-24)
  *
  * From "http://www.ft.uni-erlangen.de/~mskuhn/iso-time.html" by Markus Kuhn:
  * "Week 01 of a year is per definition the first week which has the
  * Thursday in this year, which is equivalent to the week which contains
  * the fourth day of January. In other words, the first week of a new year
  * is the week which has the majority of its days in the new year. Week 01
  * might also contain days from the previous year and the week before week
  * 01 of a year is the last week (52 or 53) of the previous year even if
  * it contains days from the new year. A week starts with Monday (day 1)
  * and ends with Sunday (day 7). For example, the first week of the year
  * 1997 lasts from 1996-12-30 to 1997-01-05..."
  * (ado, 1996-01-02)
  */
 					{
 						int			year;
 						int			base;
 						int			yday;
 						int			wday;
 						int			w;

 						year = t->tm_year;
 						base = TM_YEAR_BASE;
 						yday = t->tm_yday;
 						wday = t->tm_wday;
 						for (;;)
 						{
 							int			len;
 							int			bot;
 							int			top;

 							len = isleap_sum(year, base) ?
 								DAYSPERLYEAR :
 								DAYSPERNYEAR;

 							/*
 							 * What yday (-3 ... 3) does the ISO year begin
 							 * on?
 							 */
 							bot = ((yday + 11 - wday) %
 								   DAYSPERWEEK) - 3;

 							/*
 							 * What yday does the NEXT ISO year begin on?
 							 */
 							top = bot -
 								(len % DAYSPERWEEK);
 							if (top < -3)
 								top += DAYSPERWEEK;
 							top += len;
 							if (yday >= top)
 							{
 								++base;
 								w = 1;
 								break;
 							}
 							if (yday >= bot)
 							{
 								w = 1 + ((yday - bot) /
 										 DAYSPERWEEK);
 								break;
 							}
 							--base;
 							yday += isleap_sum(year, base) ?
 								DAYSPERLYEAR :
 								DAYSPERNYEAR;
 						}
 						if (*format == 'V')
 							pt = _conv(w, "%02d",
 									   pt, ptlim);
 						else if (*format == 'g')
 						{
 							*warnp = IN_ALL;
 							pt = _yconv(year, base, 0, 1,
 									   pt, ptlim);
 						}
 						else
 							pt = _yconv(year, base, 1, 1,
 									   pt, ptlim);
 					}
 					continue;
 				case 'v':

 					/*
 					 * From Arnold Robbins' strftime version 3.0: "date as
 					 * dd-bbb-YYYY" (ado, 1993-05-24)
 					 */
 					pt = _fmt("%e-%b-%Y", t, pt, ptlim, warnp);
 					continue;
 				case 'W':
 					pt = _conv((t->tm_yday + DAYSPERWEEK -
 								(t->tm_wday ?
 								 (t->tm_wday - 1) :
 								 (DAYSPERWEEK - 1))) / DAYSPERWEEK,
 							   "%02d", pt, ptlim);
 					continue;
 				case 'w':
 					pt = _conv(t->tm_wday, "%d", pt, ptlim);
 					continue;
 				case 'X':
 					pt = _fmt(Locale->X_fmt, t, pt, ptlim, warnp);
 					continue;
 				case 'x':
 					{
 						int			warn2 = IN_SOME;

 						pt = _fmt(Locale->x_fmt, t, pt, ptlim, &warn2);
 						if (warn2 == IN_ALL)
 							warn2 = IN_THIS;
 						if (warn2 > *warnp)
 							*warnp = warn2;
 					}
 					continue;
 				case 'y':
 					*warnp = IN_ALL;
 					pt = _yconv(t->tm_year, TM_YEAR_BASE, 0, 1,
 								pt, ptlim);
 					continue;
 				case 'Y':
 					pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 1,
 								pt, ptlim);
 					continue;
 				case 'Z':
 					if (t->tm_zone != NULL)
 						pt = _add(t->tm_zone, pt, ptlim);

 					/*
 					 * C99 says that %Z must be replaced by the empty string
 					 * if the time zone is not determinable.
 					 */
 					continue;
 				case 'z':
 					{
 						int			diff;
 						char const *sign;

 						if (t->tm_isdst < 0)
 							continue;
 						diff = t->tm_gmtoff;
 						if (diff < 0)
 						{
 							sign = "-";
 							diff = -diff;
 						}
 						else
 							sign = "+";
 						pt = _add(sign, pt, ptlim);
 						diff /= 60;
 						pt = _conv((diff / 60) * 100 + diff % 60,
 								   "%04d", pt, ptlim);
 					}
 					continue;
 				case '+':
 					pt = _fmt(Locale->date_fmt, t, pt, ptlim,
 							  warnp);
 					continue;
 				case '%':

 					/*
 					 * X311J/88-090 (4.12.3.5): if conversion char is
 					 * undefined, behavior is undefined.  Print out the
 					 * character itself as printf(3) also does.
 					 */
 				default:
 					break;
 			}
 		}
 		if (pt == ptlim)
 			break;
 		*pt++ = *format;
 	}
 	return pt;
 }

 static char *
 _conv(int n, const char *format, char *pt, const char *ptlim)
 {
 	char		buf[INT_STRLEN_MAXIMUM(int) +1];

 	(void) sprintf(buf, format, n);
 	return _add(buf, pt, ptlim);
 }

 static char *
 _add(const char *str, char *pt, const char *ptlim)
 {
 	while (pt < ptlim && (*pt = *str++) != '\0')
 		++pt;
 	return pt;
 }

 /*
  * POSIX and the C Standard are unclear or inconsistent about
  * what %C and %y do if the year is negative or exceeds 9999.
  * Use the convention that %C concatenated with %y yields the
  * same output as %Y, and that %Y contains at least 4 bytes,
  * with more only if necessary.
  */
 static char *
 _yconv(const int a, const int b, const int convert_top,
 	   const int convert_yy, char *pt, const char * const ptlim)
 {
 	int    lead;
 	int    trail;

 #define DIVISOR       100
 	trail = a % DIVISOR + b % DIVISOR;
 	lead = a / DIVISOR + b / DIVISOR + trail / DIVISOR;
 	trail %= DIVISOR;
 	if (trail < 0 && lead > 0)
 	{
 		trail += DIVISOR;
 		--lead;
 	}
 	else if (lead < 0 && trail > 0)
 	{
 		trail -= DIVISOR;
 		++lead;
 	}
 	if (convert_top)
 	{
 		if (lead == 0 && trail < 0)
 			pt = _add("-0", pt, ptlim);
 		else
 			pt = _conv(lead, "%02d", pt, ptlim);
 	}
 	if (convert_yy)
 		pt = _conv(((trail < 0) ? -trail : trail), "%02d", pt, ptlim);
 	return pt;
 }
	/*
	* Copyright (c) 1989 The Regents of the University of California.
	* All rights reserved.
	*
	* Redistribution and use in source and binary forms are permitted
	* provided that the above copyright notice and this paragraph are
	* duplicated in all such forms and that any documentation,
	* advertising materials, and other materials related to such
	* distribution and use acknowledge that the software was developed
	* by the University of California, Berkeley. The name of the
	* University may not be used to endorse or promote products derived
	* from this software without specific prior written permission.
	* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
	* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
	* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
	*
	* IDENTIFICATION
	* $PostgreSQL: pgsql/src/timezone/strftime.c,v 1.14 2009/06/11 14:49:15 momjian Exp $
	*/

	#include "postgres.h"

	#include <fcntl.h>
	#include <locale.h>

	#include "private.h"
	#include "tzfile.h"


	struct lc_time_T
	{
	const char *mon[MONSPERYEAR];
	const char *month[MONSPERYEAR];
	const char *wday[DAYSPERWEEK];
	const char *weekday[DAYSPERWEEK];
	const char *X_fmt;
	const char *x_fmt;
	const char *c_fmt;
	const char *am;
	const char *pm;
	const char *date_fmt;
	};

	#define Locale (&C_time_locale)

	static const struct lc_time_T C_time_locale = {
	{
	"Jan", "Feb", "Mar", "Apr", "May", "Jun",
	"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
	}, {
	"January", "February", "March", "April", "May", "June",
	"July", "August", "September", "October", "November", "December"
	}, {
	"Sun", "Mon", "Tue", "Wed",
	"Thu", "Fri", "Sat"
	}, {
	"Sunday", "Monday", "Tuesday", "Wednesday",
	"Thursday", "Friday", "Saturday"
	},

	/* X_fmt */
	"%H:%M:%S",

	/*
	* x_fmt
	*
	* C99 requires this format. Using just numbers (as here) makes Quakers
	* happier; it's also compatible with SVR4.
	*/
	"%m/%d/%y",

	/*
	* c_fmt
	*
	* C99 requires this format. Previously this code used "%D %X", but we now
	* conform to C99. Note that "%a %b %d %H:%M:%S %Y" is used by Solaris
	* 2.3.
	*/
	"%a %b %e %T %Y",

	/* am */
	"AM",

	/* pm */
	"PM",

	/* date_fmt */
	"%a %b %e %H:%M:%S %Z %Y"
	};

	static char _add(const char , char , const char );
	static char _conv(int, const char , char , const char );
	static char _fmt(const char , const struct pg_tm , char ,
	const char , int );
	static char * _yconv(const int, const int, const int, const int,
	char , const char const);

	#define IN_NONE 0
	#define IN_SOME 1
	#define IN_THIS 2
	#define IN_ALL 3


	size_t
	pg_strftime(char s, size_t maxsize, const char format,
	const struct pg_tm * t)
	{
	char *p;
	int warn;

	warn = IN_NONE;
	p = _fmt(((format == NULL) ? "%c" : format), t, s, s + maxsize, &warn);
	if (p == s + maxsize)
	return 0;
	*p = '\0';
	return p - s;
	}

	static char *
	_fmt(const char format, const struct pg_tm t, char pt, const char ptlim,
	int *warnp)
	{
	for (; *format; ++format)
	{
	if (*format == '%')
	{
	label:
	switch (*++format)
	{
	case '\0':
	--format;
	break;
	case 'A':
	pt = _add((t->tm_wday < 0 \|\|
	t->tm_wday >= DAYSPERWEEK) ?
	"?" : Locale->weekday[t->tm_wday],
	pt, ptlim);
	continue;
	case 'a':
	pt = _add((t->tm_wday < 0 \|\|
	t->tm_wday >= DAYSPERWEEK) ?
	"?" : Locale->wday[t->tm_wday],
	pt, ptlim);
	continue;
	case 'B':
	pt = _add((t->tm_mon < 0 \|\|
	t->tm_mon >= MONSPERYEAR) ?
	"?" : Locale->month[t->tm_mon],
	pt, ptlim);
	continue;
	case 'b':
	case 'h':
	pt = _add((t->tm_mon < 0 \|\|
	t->tm_mon >= MONSPERYEAR) ?
	"?" : Locale->mon[t->tm_mon],
	pt, ptlim);
	continue;
	case 'C':

	/*
	* %C used to do a... _fmt("%a %b %e %X %Y", t);
	* ...whereas now POSIX 1003.2 calls for something
	* completely different. (ado, 1993-05-24)
	*/
	pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 0,
	pt, ptlim);
	continue;
	case 'c':
	{
	int warn2 = IN_SOME;

	pt = _fmt(Locale->c_fmt, t, pt, ptlim, warnp);
	if (warn2 == IN_ALL)
	warn2 = IN_THIS;
	if (warn2 > *warnp)
	*warnp = warn2;
	}
	continue;
	case 'D':
	pt = _fmt("%m/%d/%y", t, pt, ptlim, warnp);
	continue;
	case 'd':
	pt = _conv(t->tm_mday, "%02d", pt, ptlim);
	continue;
	case 'E':
	case 'O':

	/*
	* C99 locale modifiers. The sequences %Ec %EC %Ex %EX
	* %Ey %EY %Od %oe %OH %OI %Om %OM %OS %Ou %OU %OV %Ow
	* %OW %Oy are supposed to provide alternate
	* representations.
	*/
	goto label;
	case 'e':
	pt = _conv(t->tm_mday, "%2d", pt, ptlim);
	continue;
	case 'F':
	pt = _fmt("%Y-%m-%d", t, pt, ptlim, warnp);
	continue;
	case 'H':
	pt = _conv(t->tm_hour, "%02d", pt, ptlim);
	continue;
	case 'I':
	pt = _conv((t->tm_hour % 12) ?
	(t->tm_hour % 12) : 12,
	"%02d", pt, ptlim);
	continue;
	case 'j':
	pt = _conv(t->tm_yday + 1, "%03d", pt, ptlim);
	continue;
	case 'k':

	/*
	* This used to be... _conv(t->tm_hour % 12 ? t->tm_hour
	* % 12 : 12, 2, ' '); ...and has been changed to the
	* below to match SunOS 4.1.1 and Arnold Robbins' strftime
	* version 3.0. That is, "%k" and "%l" have been swapped.
	* (ado, 1993-05-24)
	*/
	pt = _conv(t->tm_hour, "%2d", pt, ptlim);
	continue;
	#ifdef KITCHEN_SINK
	case 'K':

	/*
	* * After all this time, still unclaimed!
	*/
	pt = _add("kitchen sink", pt, ptlim);
	continue;
	#endif /* defined KITCHEN_SINK */
	case 'l':

	/*
	* This used to be... _conv(t->tm_hour, 2, ' '); ...and
	* has been changed to the below to match SunOS 4.1.1 and
	* Arnold Robbin's strftime version 3.0. That is, "%k" and
	* "%l" have been swapped. (ado, 1993-05-24)
	*/
	pt = _conv((t->tm_hour % 12) ?
	(t->tm_hour % 12) : 12,
	"%2d", pt, ptlim);
	continue;
	case 'M':
	pt = _conv(t->tm_min, "%02d", pt, ptlim);
	continue;
	case 'm':
	pt = _conv(t->tm_mon + 1, "%02d", pt, ptlim);
	continue;
	case 'n':
	pt = _add("\n", pt, ptlim);
	continue;
	case 'p':
	pt = _add((t->tm_hour >= (HOURSPERDAY / 2)) ?
	Locale->pm :
	Locale->am,
	pt, ptlim);
	continue;
	case 'R':
	pt = _fmt("%H:%M", t, pt, ptlim, warnp);
	continue;
	case 'r':
	pt = _fmt("%I:%M:%S %p", t, pt, ptlim, warnp);
	continue;
	case 'S':
	pt = _conv(t->tm_sec, "%02d", pt, ptlim);
	continue;
	case 'T':
	pt = _fmt("%H:%M:%S", t, pt, ptlim, warnp);
	continue;
	case 't':
	pt = _add("\t", pt, ptlim);
	continue;
	case 'U':
	pt = _conv((t->tm_yday + DAYSPERWEEK -
	t->tm_wday) / DAYSPERWEEK,
	"%02d", pt, ptlim);
	continue;
	case 'u':

	/*
	* From Arnold Robbins' strftime version 3.0: "ISO 8601:
	* Weekday as a decimal number [1 (Monday) - 7]" (ado,
	* 1993-05-24)
	*/
	pt = _conv((t->tm_wday == 0) ?
	DAYSPERWEEK : t->tm_wday,
	"%d", pt, ptlim);
	continue;
	case 'V': /* ISO 8601 week number */
	case 'G': /* ISO 8601 year (four digits) */
	case 'g': /* ISO 8601 year (two digits) */
	/*
	* From Arnold Robbins' strftime version 3.0: "the week number of the
	* year (the first Monday as the first day of week 1) as a decimal number
	* (01-53)."
	* (ado, 1993-05-24)
	*
	* From "http://www.ft.uni-erlangen.de/~mskuhn/iso-time.html" by Markus Kuhn:
	* "Week 01 of a year is per definition the first week which has the
	* Thursday in this year, which is equivalent to the week which contains
	* the fourth day of January. In other words, the first week of a new year
	* is the week which has the majority of its days in the new year. Week 01
	* might also contain days from the previous year and the week before week
	* 01 of a year is the last week (52 or 53) of the previous year even if
	* it contains days from the new year. A week starts with Monday (day 1)
	* and ends with Sunday (day 7). For example, the first week of the year
	* 1997 lasts from 1996-12-30 to 1997-01-05..."
	* (ado, 1996-01-02)
	*/
	{
	int year;
	int base;
	int yday;
	int wday;
	int w;

	year = t->tm_year;
	base = TM_YEAR_BASE;
	yday = t->tm_yday;
	wday = t->tm_wday;
	for (;;)
	{
	int len;
	int bot;
	int top;

	len = isleap_sum(year, base) ?
	DAYSPERLYEAR :
	DAYSPERNYEAR;

	/*
	* What yday (-3 ... 3) does the ISO year begin
	* on?
	*/
	bot = ((yday + 11 - wday) %
	DAYSPERWEEK) - 3;

	/*
	* What yday does the NEXT ISO year begin on?
	*/
	top = bot -
	(len % DAYSPERWEEK);
	if (top < -3)
	top += DAYSPERWEEK;
	top += len;
	if (yday >= top)
	{
	++base;
	w = 1;
	break;
	}
	if (yday >= bot)
	{
	w = 1 + ((yday - bot) /
	DAYSPERWEEK);
	break;
	}
	--base;
	yday += isleap_sum(year, base) ?
	DAYSPERLYEAR :
	DAYSPERNYEAR;
	}
	if (*format == 'V')
	pt = _conv(w, "%02d",
	pt, ptlim);
	else if (*format == 'g')
	{
	*warnp = IN_ALL;
	pt = _yconv(year, base, 0, 1,
	pt, ptlim);
	}
	else
	pt = _yconv(year, base, 1, 1,
	pt, ptlim);
	}
	continue;
	case 'v':

	/*
	* From Arnold Robbins' strftime version 3.0: "date as
	* dd-bbb-YYYY" (ado, 1993-05-24)
	*/
	pt = _fmt("%e-%b-%Y", t, pt, ptlim, warnp);
	continue;
	case 'W':
	pt = _conv((t->tm_yday + DAYSPERWEEK -
	(t->tm_wday ?
	(t->tm_wday - 1) :
	(DAYSPERWEEK - 1))) / DAYSPERWEEK,
	"%02d", pt, ptlim);
	continue;
	case 'w':
	pt = _conv(t->tm_wday, "%d", pt, ptlim);
	continue;
	case 'X':
	pt = _fmt(Locale->X_fmt, t, pt, ptlim, warnp);
	continue;
	case 'x':
	{
	int warn2 = IN_SOME;

	pt = _fmt(Locale->x_fmt, t, pt, ptlim, &warn2);
	if (warn2 == IN_ALL)
	warn2 = IN_THIS;
	if (warn2 > *warnp)
	*warnp = warn2;
	}
	continue;
	case 'y':
	*warnp = IN_ALL;
	pt = _yconv(t->tm_year, TM_YEAR_BASE, 0, 1,
	pt, ptlim);
	continue;
	case 'Y':
	pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 1,
	pt, ptlim);
	continue;
	case 'Z':
	if (t->tm_zone != NULL)
	pt = _add(t->tm_zone, pt, ptlim);

	/*
	* C99 says that %Z must be replaced by the empty string
	* if the time zone is not determinable.
	*/
	continue;
	case 'z':
	{
	int diff;
	char const *sign;

	if (t->tm_isdst < 0)
	continue;
	diff = t->tm_gmtoff;
	if (diff < 0)
	{
	sign = "-";
	diff = -diff;
	}
	else
	sign = "+";
	pt = _add(sign, pt, ptlim);
	diff /= 60;
	pt = _conv((diff / 60) * 100 + diff % 60,
	"%04d", pt, ptlim);
	}
	continue;
	case '+':
	pt = _fmt(Locale->date_fmt, t, pt, ptlim,
	warnp);
	continue;
	case '%':

	/*
	* X311J/88-090 (4.12.3.5): if conversion char is
	* undefined, behavior is undefined. Print out the
	* character itself as printf(3) also does.
	*/
	default:
	break;
	}
	}
	if (pt == ptlim)
	break;
	pt++ = format;
	}
	return pt;
	}

	static char *
	_conv(int n, const char format, char pt, const char *ptlim)
	{
	char buf[INT_STRLEN_MAXIMUM(int) +1];

	(void) sprintf(buf, format, n);
	return _add(buf, pt, ptlim);
	}

	static char *
	_add(const char str, char pt, const char *ptlim)
	{
	while (pt < ptlim && (pt = str++) != '\0')
	++pt;
	return pt;
	}

	/*
	* POSIX and the C Standard are unclear or inconsistent about
	* what %C and %y do if the year is negative or exceeds 9999.
	* Use the convention that %C concatenated with %y yields the
	* same output as %Y, and that %Y contains at least 4 bytes,
	* with more only if necessary.
	*/
	static char *
	_yconv(const int a, const int b, const int convert_top,
	const int convert_yy, char pt, const char const ptlim)
	{
	int lead;
	int trail;

	#define DIVISOR 100
	trail = a % DIVISOR + b % DIVISOR;
	lead = a / DIVISOR + b / DIVISOR + trail / DIVISOR;
	trail %= DIVISOR;
	if (trail < 0 && lead > 0)
	{
	trail += DIVISOR;
	--lead;
	}
	else if (lead < 0 && trail > 0)
	{
	trail -= DIVISOR;
	++lead;
	}
	if (convert_top)
	{
	if (lead == 0 && trail < 0)
	pt = _add("-0", pt, ptlim);
	else
	pt = _conv(lead, "%02d", pt, ptlim);
	}
	if (convert_yy)
	pt = _conv(((trail < 0) ? -trail : trail), "%02d", pt, ptlim);
	return pt;
	}