StdLib/LibC/Time/strftime.c - third_party/edk2 - Git at Google

 /** @file
     Implementation of the strftime function for <time.h>.

     Based on the UCB version with the ID appearing below.
     This is ANSIish only when "multibyte character == plain character".

     Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>
     This program and the accompanying materials are licensed and made available under
     the terms and conditions of the BSD License that accompanies this distribution.
     The full text of the license may be found at
     http://opensource.org/licenses/bsd-license.php.

     THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
     WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.

     Copyright (c) 1989, 1993
     The Regents of the University of California.  All rights reserved.

     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions
     are met:
     1. Redistributions of source code must retain the above copyright
       notice, this list of conditions and the following disclaimer.
     2. Redistributions in binary form must reproduce the above copyright
       notice, this list of conditions and the following disclaimer in the
       documentation and/or other materials provided with the distribution.
     3. All advertising materials mentioning features or use of this software
       must display the following acknowledgement:
     This product includes software developed by the University of
     California, Berkeley and its contributors.
     4. Neither the name of the University nor the names of its contributors
       may be used to endorse or promote products derived from this software
       without specific prior written permission.

     THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     SUCH DAMAGE.

   NetBSD: strftime.c,v 1.17.4.1 2007/08/21 20:08:21 liamjfoy Exp
 **/
 #include  <LibConfig.h>
 #include <sys/EfiCdefs.h>

 #include "namespace.h"
 #include <time.h>
 #include "tzfile.h"
 #include  "TimeVals.h"
 #include "fcntl.h"
 #include "locale.h"

 #include "sys/localedef.h"
 #include  <MainData.h>

 /*
 ** We don't use these extensions in strftime operation even when
 ** supported by the local tzcode configuration.  A strictly
 ** conforming C application may leave them in undefined state.
 */

 #ifdef _LIBC
 #undef TM_ZONE
 #undef TM_GMTOFF
 #endif

 #define Locale  _CurrentTimeLocale

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

 #define NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU

 #ifndef YEAR_2000_NAME
 #define YEAR_2000_NAME  "CHECK_STRFTIME_FORMATS_FOR_TWO_DIGIT_YEARS"
 #endif /* !defined YEAR_2000_NAME */


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

 size_t
 strftime(
   char            * __restrict  s,
   size_t                        maxsize,
   const char      * __restrict  format,
   const struct tm * __restrict  timeptr
   )
 {
   char *  p;
   int warn;

   tzset();
   warn = IN_NONE;
   p = _fmt(((format == NULL) ? "%c" : format), timeptr, s, s + maxsize, &warn);

 #ifndef NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU
   if (warn != IN_NONE && getenv(YEAR_2000_NAME) != NULL) {
     (void) fprintf(stderr, "\n");
     if (format == NULL)
       (void) fprintf(stderr, "NULL strftime format ");
     else  (void) fprintf(stderr, "strftime format \"%s\" ",
         format);
     (void) fprintf(stderr, "yields only two digits of years in ");
     if (warn == IN_SOME)
       (void) fprintf(stderr, "some locales");
     else if (warn == IN_THIS)
       (void) fprintf(stderr, "the current locale");
     else  (void) fprintf(stderr, "all locales");
     (void) fprintf(stderr, "\n");
   }
 #endif /* !defined NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU */

   if (p == s + maxsize)
     return 0;
   *p = '\0';
   return p - s;
 }

 static char *
 _fmt(
   const char      *       format,
   const struct tm * const t,
   char            *       pt,
   const char      * const 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->day[t->tm_wday],
           pt, ptlim);
         continue;
       case 'a':
         pt = _add((t->tm_wday < 0 ||
           t->tm_wday >= DAYSPERWEEK) ?
           "?" : Locale->abday[t->tm_wday],
           pt, ptlim);
         continue;
       case 'B':
         pt = _add((t->tm_mon < 0 ||
           t->tm_mon >= MONSPERYEAR) ?
           "?" : Locale->mon[t->tm_mon],
           pt, ptlim);
         continue;
       case 'b':
       case 'h':
         pt = _add((t->tm_mon < 0 ||
           t->tm_mon >= MONSPERYEAR) ?
           "?" : Locale->abmon[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 = _conv((t->tm_year + TM_YEAR_BASE) / 100,
           "%02d", pt, ptlim);
         continue;
       case 'c':
         {
         int warn2 = IN_SOME;

         pt = _fmt(Locale->d_t_fmt, t, pt, ptlim, &warn2);
         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->am_pm[1] :
           Locale->am_pm[0],
           pt, ptlim);
         continue;
       case 'R':
         pt = _fmt("%H:%M", t, pt, ptlim, warnp);
         continue;
       case 'r':
         pt = _fmt(Locale->t_fmt_ampm, t, pt, ptlim,
                 warnp);
         continue;
       case 'S':
         pt = _conv(t->tm_sec, "%02d", pt, ptlim);
         continue;
       case 's':
         {
           struct tm tm;
           char    buf[INT_STRLEN_MAXIMUM(
                 time_t) + 1];
           time_t    mkt;

           tm = *t;
           mkt = mktime(&tm);
           /* CONSTCOND */
           if (TYPE_SIGNED(time_t))
             (void) sprintf(buf, "%ld",
               (long) mkt);
           else  (void) sprintf(buf, "%lu",
               (unsigned long) mkt);
           pt = _add(buf, 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 yday;
           int wday;
           int w;

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

             len = isleap(year) ?
               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) {
               ++year;
               w = 1;
               break;
             }
             if (yday >= bot) {
               w = 1 + ((yday - bot) /
                 DAYSPERWEEK);
               break;
             }
             --year;
             yday += isleap(year) ?
               DAYSPERLYEAR :
               DAYSPERNYEAR;
           }
 #ifdef XPG4_1994_04_09
           if ((w == 52
                && t->tm_mon == TM_JANUARY)
               || (w == 1
             && t->tm_mon == TM_DECEMBER))
             w = 53;
 #endif /* defined XPG4_1994_04_09 */
           if (*format == 'V')
             pt = _conv(w, "%02d",
               pt, ptlim);
           else if (*format == 'g') {
             *warnp = IN_ALL;
             pt = _conv(year % 100, "%02d",
               pt, ptlim);
           } else  pt = _conv(year, "%04d",
               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->t_fmt, t, pt, ptlim, warnp);
         continue;
       case 'x':
         {
         int warn2 = IN_SOME;

         pt = _fmt(Locale->d_fmt, t, pt, ptlim, &warn2);
         if (warn2 == IN_ALL)
           warn2 = IN_THIS;
         if (warn2 > *warnp)
           *warnp = warn2;
         }
         continue;
       case 'y':
         *warnp = IN_ALL;
         pt = _conv((t->tm_year + TM_YEAR_BASE) % 100,
           "%02d", pt, ptlim);
         continue;
       case 'Y':
         pt = _conv(t->tm_year + TM_YEAR_BASE, "%04d",
           pt, ptlim);
         continue;
       case 'Z':
 #ifdef TM_ZONE
         if (t->TM_ZONE != NULL)
           pt = _add(t->TM_ZONE, pt, ptlim);
         else
 #endif /* defined TM_ZONE */
         if (t->tm_isdst >= 0)
           pt = _add(tzname[t->tm_isdst != 0],
             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;
 #ifdef TM_GMTOFF
         diff = (int)t->TM_GMTOFF;
 #else /* !defined TM_GMTOFF */
         /*
         ** C99 says that the UTC offset must
         ** be computed by looking only at
         ** tm_isdst.  This requirement is
         ** incorrect, since it means the code
         ** must rely on magic (in this case
         ** altzone and timezone), and the
         ** magic might not have the correct
         ** offset.  Doing things correctly is
         ** tricky and requires disobeying C99;
         ** see GNU C strftime for details.
         ** For now, punt and conform to the
         ** standard, even though it's incorrect.
         **
         ** C99 says that %z must be replaced by the
         ** empty string if the time zone is not
         ** determinable, so output nothing if the
         ** appropriate variables are not available.
         */
 #ifndef STD_INSPIRED
         if (t->tm_isdst == 0)
 #ifdef USG_COMPAT
           diff = -timezone;
 #else /* !defined USG_COMPAT */
           continue;
 #endif /* !defined USG_COMPAT */
         else
 #ifdef ALTZONE
           diff = -altzone;
 #else /* !defined ALTZONE */
           continue;
 #endif /* !defined ALTZONE */
 #else /* defined STD_INSPIRED */
         {
           struct tm tmp;
           time_t lct, gct;

           /*
           ** Get calendar time from t
           ** being treated as local.
           */
           tmp = *t; /* mktime discards const */
           lct = mktime(&tmp);

           if (lct == (time_t)-1)
             continue;

           /*
           ** Get calendar time from t
           ** being treated as GMT.
           **/
           tmp = *t; /* mktime discards const */
           gct = timegm(&tmp);

           if (gct == (time_t)-1)
             continue;

           /* LINTED difference will fit int */
           diff = (intmax_t)gct - (intmax_t)lct;
         }
 #endif /* defined STD_INSPIRED */
 #endif /* !defined 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;
 #if 0
       case '+':
         pt = _fmt(Locale->date_fmt, t, pt, ptlim,
           warnp);
         continue;
 #endif
       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(
   const int             n,
   const char  * const   format,
   char        * const   pt,
   const char  * const   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  * const ptlim
 )
 {
   while (pt < ptlim && (*pt = *str++) != '\0')
     ++pt;
   return pt;
 }
	/** @file
	Implementation of the strftime function for <time.h>.

	Based on the UCB version with the ID appearing below.
	This is ANSIish only when "multibyte character == plain character".

	Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>
	This program and the accompanying materials are licensed and made available under
	the terms and conditions of the BSD License that accompanies this distribution.
	The full text of the license may be found at
	http://opensource.org/licenses/bsd-license.php.

	THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
	WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.

	Copyright (c) 1989, 1993
	The Regents of the University of California. All rights reserved.

	Redistribution and use in source and binary forms, with or without
	modification, are permitted provided that the following conditions
	are met:
	1. Redistributions of source code must retain the above copyright
	notice, this list of conditions and the following disclaimer.
	2. Redistributions in binary form must reproduce the above copyright
	notice, this list of conditions and the following disclaimer in the
	documentation and/or other materials provided with the distribution.
	3. All advertising materials mentioning features or use of this software
	must display the following acknowledgement:
	This product includes software developed by the University of
	California, Berkeley and its contributors.
	4. Neither the name of the University nor the names of its contributors
	may be used to endorse or promote products derived from this software
	without specific prior written permission.

	THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	SUCH DAMAGE.

	NetBSD: strftime.c,v 1.17.4.1 2007/08/21 20:08:21 liamjfoy Exp
	**/
	#include <LibConfig.h>
	#include <sys/EfiCdefs.h>

	#include "namespace.h"
	#include <time.h>
	#include "tzfile.h"
	#include "TimeVals.h"
	#include "fcntl.h"
	#include "locale.h"

	#include "sys/localedef.h"
	#include <MainData.h>

	/*
	** We don't use these extensions in strftime operation even when
	** supported by the local tzcode configuration. A strictly
	** conforming C application may leave them in undefined state.
	*/

	#ifdef _LIBC
	#undef TM_ZONE
	#undef TM_GMTOFF
	#endif

	#define Locale _CurrentTimeLocale

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

	#define NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU

	#ifndef YEAR_2000_NAME
	#define YEAR_2000_NAME "CHECK_STRFTIME_FORMATS_FOR_TWO_DIGIT_YEARS"
	#endif /* !defined YEAR_2000_NAME */


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

	size_t
	strftime(
	char * __restrict s,
	size_t maxsize,
	const char * __restrict format,
	const struct tm * __restrict timeptr
	)
	{
	char * p;
	int warn;

	tzset();
	warn = IN_NONE;
	p = _fmt(((format == NULL) ? "%c" : format), timeptr, s, s + maxsize, &warn);

	#ifndef NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU
	if (warn != IN_NONE && getenv(YEAR_2000_NAME) != NULL) {
	(void) fprintf(stderr, "\n");
	if (format == NULL)
	(void) fprintf(stderr, "NULL strftime format ");
	else (void) fprintf(stderr, "strftime format \"%s\" ",
	format);
	(void) fprintf(stderr, "yields only two digits of years in ");
	if (warn == IN_SOME)
	(void) fprintf(stderr, "some locales");
	else if (warn == IN_THIS)
	(void) fprintf(stderr, "the current locale");
	else (void) fprintf(stderr, "all locales");
	(void) fprintf(stderr, "\n");
	}
	#endif /* !defined NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU */

	if (p == s + maxsize)
	return 0;
	*p = '\0';
	return p - s;
	}

	static char *
	_fmt(
	const char * format,
	const struct tm * const t,
	char * pt,
	const char * const 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->day[t->tm_wday],
	pt, ptlim);
	continue;
	case 'a':
	pt = _add((t->tm_wday < 0 \|\|
	t->tm_wday >= DAYSPERWEEK) ?
	"?" : Locale->abday[t->tm_wday],
	pt, ptlim);
	continue;
	case 'B':
	pt = _add((t->tm_mon < 0 \|\|
	t->tm_mon >= MONSPERYEAR) ?
	"?" : Locale->mon[t->tm_mon],
	pt, ptlim);
	continue;
	case 'b':
	case 'h':
	pt = _add((t->tm_mon < 0 \|\|
	t->tm_mon >= MONSPERYEAR) ?
	"?" : Locale->abmon[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 = _conv((t->tm_year + TM_YEAR_BASE) / 100,
	"%02d", pt, ptlim);
	continue;
	case 'c':
	{
	int warn2 = IN_SOME;

	pt = _fmt(Locale->d_t_fmt, t, pt, ptlim, &warn2);
	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->am_pm[1] :
	Locale->am_pm[0],
	pt, ptlim);
	continue;
	case 'R':
	pt = _fmt("%H:%M", t, pt, ptlim, warnp);
	continue;
	case 'r':
	pt = _fmt(Locale->t_fmt_ampm, t, pt, ptlim,
	warnp);
	continue;
	case 'S':
	pt = _conv(t->tm_sec, "%02d", pt, ptlim);
	continue;
	case 's':
	{
	struct tm tm;
	char buf[INT_STRLEN_MAXIMUM(
	time_t) + 1];
	time_t mkt;

	tm = *t;
	mkt = mktime(&tm);
	/* CONSTCOND */
	if (TYPE_SIGNED(time_t))
	(void) sprintf(buf, "%ld",
	(long) mkt);
	else (void) sprintf(buf, "%lu",
	(unsigned long) mkt);
	pt = _add(buf, 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 yday;
	int wday;
	int w;

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

	len = isleap(year) ?
	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) {
	++year;
	w = 1;
	break;
	}
	if (yday >= bot) {
	w = 1 + ((yday - bot) /
	DAYSPERWEEK);
	break;
	}
	--year;
	yday += isleap(year) ?
	DAYSPERLYEAR :
	DAYSPERNYEAR;
	}
	#ifdef XPG4_1994_04_09
	if ((w == 52
	&& t->tm_mon == TM_JANUARY)
	\|\| (w == 1
	&& t->tm_mon == TM_DECEMBER))
	w = 53;
	#endif /* defined XPG4_1994_04_09 */
	if (*format == 'V')
	pt = _conv(w, "%02d",
	pt, ptlim);
	else if (*format == 'g') {
	*warnp = IN_ALL;
	pt = _conv(year % 100, "%02d",
	pt, ptlim);
	} else pt = _conv(year, "%04d",
	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->t_fmt, t, pt, ptlim, warnp);
	continue;
	case 'x':
	{
	int warn2 = IN_SOME;

	pt = _fmt(Locale->d_fmt, t, pt, ptlim, &warn2);
	if (warn2 == IN_ALL)
	warn2 = IN_THIS;
	if (warn2 > *warnp)
	*warnp = warn2;
	}
	continue;
	case 'y':
	*warnp = IN_ALL;
	pt = _conv((t->tm_year + TM_YEAR_BASE) % 100,
	"%02d", pt, ptlim);
	continue;
	case 'Y':
	pt = _conv(t->tm_year + TM_YEAR_BASE, "%04d",
	pt, ptlim);
	continue;
	case 'Z':
	#ifdef TM_ZONE
	if (t->TM_ZONE != NULL)
	pt = _add(t->TM_ZONE, pt, ptlim);
	else
	#endif /* defined TM_ZONE */
	if (t->tm_isdst >= 0)
	pt = _add(tzname[t->tm_isdst != 0],
	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;
	#ifdef TM_GMTOFF
	diff = (int)t->TM_GMTOFF;
	#else /* !defined TM_GMTOFF */
	/*
	** C99 says that the UTC offset must
	** be computed by looking only at
	** tm_isdst. This requirement is
	** incorrect, since it means the code
	** must rely on magic (in this case
	** altzone and timezone), and the
	** magic might not have the correct
	** offset. Doing things correctly is
	** tricky and requires disobeying C99;
	** see GNU C strftime for details.
	** For now, punt and conform to the
	** standard, even though it's incorrect.
	**
	** C99 says that %z must be replaced by the
	** empty string if the time zone is not
	** determinable, so output nothing if the
	** appropriate variables are not available.
	*/
	#ifndef STD_INSPIRED
	if (t->tm_isdst == 0)
	#ifdef USG_COMPAT
	diff = -timezone;
	#else /* !defined USG_COMPAT */
	continue;
	#endif /* !defined USG_COMPAT */
	else
	#ifdef ALTZONE
	diff = -altzone;
	#else /* !defined ALTZONE */
	continue;
	#endif /* !defined ALTZONE */
	#else /* defined STD_INSPIRED */
	{
	struct tm tmp;
	time_t lct, gct;

	/*
	** Get calendar time from t
	** being treated as local.
	*/
	tmp = t; / mktime discards const */
	lct = mktime(&tmp);

	if (lct == (time_t)-1)
	continue;

	/*
	** Get calendar time from t
	** being treated as GMT.
	**/
	tmp = t; / mktime discards const */
	gct = timegm(&tmp);

	if (gct == (time_t)-1)
	continue;

	/* LINTED difference will fit int */
	diff = (intmax_t)gct - (intmax_t)lct;
	}
	#endif /* defined STD_INSPIRED */
	#endif /* !defined 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;
	#if 0
	case '+':
	pt = _fmt(Locale->date_fmt, t, pt, ptlim,
	warnp);
	continue;
	#endif
	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(
	const int n,
	const char * const format,
	char * const pt,
	const char * const 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 * const ptlim
	)
	{
	while (pt < ptlim && (pt = str++) != '\0')
	++pt;
	return pt;
	}