strftime.c   [plain text]

/* Copyright (C) 1991-1999, 2000, 2001, 2003, 2004, 2005 Free Software
   Foundation, Inc.

   NOTE: The canonical source of this file is maintained with the GNU C Library.
   Bugs can be reported to bug-glibc@prep.ai.mit.edu.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License along
   with this program; if not, write to the Free Software Foundation,
   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#ifdef _LIBC
# define HAVE_MBLEN 1
# define HAVE_MBRLEN 1
# define HAVE_STRUCT_ERA_ENTRY 1
# define HAVE_TM_GMTOFF 1
# define HAVE_TM_ZONE 1
# define HAVE_TZNAME 1
# define HAVE_TZSET 1
# define MULTIBYTE_IS_FORMAT_SAFE 1
# include "../locale/localeinfo.h"
#endif

#include <ctype.h>
#include <sys/types.h>		/* Some systems define `time_t' here.  */

#ifdef TIME_WITH_SYS_TIME
# include <sys/time.h>
# include <time.h>
#else
# ifdef HAVE_SYS_TIME_H
#  include <sys/time.h>
# else
#  include <time.h>
# endif
#endif
#if HAVE_TZNAME
extern char *tzname[];
#endif

/* Do multibyte processing if multibytes are supported, unless
   multibyte sequences are safe in formats.  Multibyte sequences are
   safe if they cannot contain byte sequences that look like format
   conversion specifications.  The GNU C Library uses UTF8 multibyte
   encoding, which is safe for formats, but strftime.c can be used
   with other C libraries that use unsafe encodings.  */
#define DO_MULTIBYTE (HAVE_MBLEN && HAVE_WCHAR_H && ! MULTIBYTE_IS_FORMAT_SAFE)

#if DO_MULTIBYTE
# if HAVE_MBRLEN
#  include <wchar.h>
# else
   /* Simulate mbrlen with mblen as best we can.  */
#  define mbstate_t int
#  define mbrlen(s, n, ps) mblen (s, n)
#  define mbsinit(ps) (*(ps) == 0)
# endif
  static const mbstate_t mbstate_zero;
#endif

#include <limits.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>

#ifdef COMPILE_WIDE
# include <endian.h>
# define CHAR_T wchar_t
# define UCHAR_T unsigned int
# define L_(Str) L##Str
# define NLW(Sym) _NL_W##Sym

# define MEMCPY(d, s, n) __wmemcpy (d, s, n)
# define STRLEN(s) __wcslen (s)

#else
# define CHAR_T char
# define UCHAR_T unsigned char
# define L_(Str) Str
# define NLW(Sym) Sym

# define MEMCPY(d, s, n) memcpy (d, s, n)
# define STRLEN(s) strlen (s)

# ifdef _LIBC
#  define MEMPCPY(d, s, n) __mempcpy (d, s, n)
# else
#  ifndef HAVE_MEMPCPY
#   define MEMPCPY(d, s, n) ((void *) ((char *) memcpy (d, s, n) + (n)))
#  endif
# endif
#endif

/* Shift A right by B bits portably, by dividing A by 2**B and
   truncating towards minus infinity.  A and B should be free of side
   effects, and B should be in the range 0 <= B <= INT_BITS - 2, where
   INT_BITS is the number of useful bits in an int.  GNU code can
   assume that INT_BITS is at least 32.

   ISO C99 says that A >> B is implementation-defined if A < 0.  Some
   implementations (e.g., UNICOS 9.0 on a Cray Y-MP EL) don't shift
   right in the usual way when A < 0, so SHR falls back on division if
   ordinary A >> B doesn't seem to be the usual signed shift.  */
#define SHR(a, b)	\
  (-1 >> 1 == -1	\
   ? (a) >> (b)		\
   : (a) / (1 << (b)) - ((a) % (1 << (b)) < 0))

/* Bound on length of the string representing an integer type or expression T.
   Subtract 1 for the sign bit if t is signed; log10 (2.0) < 146/485;
   add 1 for integer division truncation; add 1 more for a minus sign
   if needed.  */
#define INT_STRLEN_BOUND(t) \
  ((sizeof (t) * CHAR_BIT - 1) * 146 / 485 + 2)

#define TM_YEAR_BASE 1900

#ifndef __isleap
/* Nonzero if YEAR is a leap year (every 4 years,
   except every 100th isn't, and every 400th is).  */
# define __isleap(year)	\
  ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))
#endif


#ifdef _LIBC
# define tzname __tzname
# define tzset __tzset
#endif

#if !HAVE_TM_GMTOFF
/* Portable standalone applications should supply a "time_r.h" that
   declares a POSIX-compliant localtime_r, for the benefit of older
   implementations that lack localtime_r or have a nonstandard one.
   See the gnulib time_r module for one way to implement this.  */
# include "time_r.h"
# undef __gmtime_r
# undef __localtime_r
# define __gmtime_r gmtime_r
# define __localtime_r localtime_r
#endif


#ifdef COMPILE_WIDE
# define memset_space(P, Len) (wmemset (P, L' ', Len), (P) += (Len))
# define memset_zero(P, Len) (wmemset (P, L'0', Len), (P) += (Len))
#else
# define memset_space(P, Len) (memset (P, ' ', Len), (P) += (Len))
# define memset_zero(P, Len) (memset (P, '0', Len), (P) += (Len))
#endif

#define add(n, f)							      \
  do									      \
    {									      \
      int _n = (n);							      \
      int _delta = width - _n;						      \
      int _incr = _n + (_delta > 0 ? _delta : 0);			      \
      if ((size_t) _incr >= maxsize - i)				      \
	return 0;							      \
      if (p)								      \
	{								      \
	  if (_delta > 0)						      \
	    {								      \
	      if (pad == L_('0'))					      \
		memset_zero (p, _delta);				      \
	      else							      \
		memset_space (p, _delta);				      \
	    }								      \
	  f;								      \
	  p += _n;							      \
	}								      \
      i += _incr;							      \
    } while (0)

#define cpy(n, s) \
    add ((n),								      \
	 if (to_lowcase)						      \
	   memcpy_lowcase (p, (s), _n LOCALE_ARG);			      \
	 else if (to_uppcase)						      \
	   memcpy_uppcase (p, (s), _n LOCALE_ARG);			      \
	 else								      \
	   MEMCPY ((void *) p, (void const *) (s), _n))

#ifdef COMPILE_WIDE
# ifndef USE_IN_EXTENDED_LOCALE_MODEL
#  undef __mbsrtowcs_l
#  define __mbsrtowcs_l(d, s, l, st, loc) __mbsrtowcs (d, s, l, st)
# endif
# define widen(os, ws, l) \
  {									      \
    mbstate_t __st;							      \
    const char *__s = os;						      \
    memset (&__st, '\0', sizeof (__st));				      \
    l = __mbsrtowcs_l (NULL, &__s, 0, &__st, loc);			      \
    ws = (wchar_t *) alloca ((l + 1) * sizeof (wchar_t));		      \
    (void) __mbsrtowcs_l (ws, &__s, l, &__st, loc);			      \
  }
#endif


#if defined _LIBC && defined USE_IN_EXTENDED_LOCALE_MODEL
/* We use this code also for the extended locale handling where the
   function gets as an additional argument the locale which has to be
   used.  To access the values we have to redefine the _NL_CURRENT
   macro.  */
# define strftime		__strftime_l
# define wcsftime		__wcsftime_l
# undef _NL_CURRENT
# define _NL_CURRENT(category, item) \
  (current->values[_NL_ITEM_INDEX (item)].string)
# define LOCALE_ARG , loc
# define LOCALE_PARAM_PROTO , __locale_t loc
# define HELPER_LOCALE_ARG  , current
#else
# define LOCALE_PARAM_PROTO
# define LOCALE_ARG
# ifdef _LIBC
#  define HELPER_LOCALE_ARG , _NL_CURRENT_DATA (LC_TIME)
# else
#  define HELPER_LOCALE_ARG
# endif
#endif

#ifdef COMPILE_WIDE
# ifdef USE_IN_EXTENDED_LOCALE_MODEL
#  define TOUPPER(Ch, L) __towupper_l (Ch, L)
#  define TOLOWER(Ch, L) __towlower_l (Ch, L)
# else
#  define TOUPPER(Ch, L) towupper (Ch)
#  define TOLOWER(Ch, L) towlower (Ch)
# endif
#else
# ifdef _LIBC
#  ifdef USE_IN_EXTENDED_LOCALE_MODEL
#   define TOUPPER(Ch, L) __toupper_l (Ch, L)
#   define TOLOWER(Ch, L) __tolower_l (Ch, L)
#  else
#   define TOUPPER(Ch, L) toupper (Ch)
#   define TOLOWER(Ch, L) tolower (Ch)
#  endif
# else
#  define TOUPPER(Ch, L) (islower (Ch) ? toupper (Ch) : (Ch))
#  define TOLOWER(Ch, L) (isupper (Ch) ? tolower (Ch) : (Ch))
# endif
#endif
/* We don't use `isdigit' here since the locale dependent
   interpretation is not what we want here.  We only need to accept
   the arabic digits in the ASCII range.  One day there is perhaps a
   more reliable way to accept other sets of digits.  */
#define ISDIGIT(Ch) ((unsigned int) (Ch) - L_('0') <= 9)

static CHAR_T *
memcpy_lowcase (CHAR_T *dest, const CHAR_T *src,
		size_t len LOCALE_PARAM_PROTO)
{
  while (len-- > 0)
    dest[len] = TOLOWER ((UCHAR_T) src[len], loc);
  return dest;
}

static CHAR_T *
memcpy_uppcase (CHAR_T *dest, const CHAR_T *src,
		size_t len LOCALE_PARAM_PROTO)
{
  while (len-- > 0)
    dest[len] = TOUPPER ((UCHAR_T) src[len], loc);
  return dest;
}


#if ! HAVE_TM_GMTOFF
/* Yield the difference between *A and *B,
   measured in seconds, ignoring leap seconds.  */
# define tm_diff ftime_tm_diff
static int
tm_diff (const struct tm *a, const struct tm *b)
{
  /* Compute intervening leap days correctly even if year is negative.
     Take care to avoid int overflow in leap day calculations,
     but it's OK to assume that A and B are close to each other.  */
  int a4 = SHR (a->tm_year, 2) + SHR (TM_YEAR_BASE, 2) - ! (a->tm_year & 3);
  int b4 = SHR (b->tm_year, 2) + SHR (TM_YEAR_BASE, 2) - ! (b->tm_year & 3);
  int a100 = a4 / 25 - (a4 % 25 < 0);
  int b100 = b4 / 25 - (b4 % 25 < 0);
  int a400 = SHR (a100, 2);
  int b400 = SHR (b100, 2);
  int intervening_leap_days = (a4 - b4) - (a100 - b100) + (a400 - b400);
  int years = a->tm_year - b->tm_year;
  int days = (365 * years + intervening_leap_days
	      + (a->tm_yday - b->tm_yday));
  return (60 * (60 * (24 * days + (a->tm_hour - b->tm_hour))
		+ (a->tm_min - b->tm_min))
	  + (a->tm_sec - b->tm_sec));
}
#endif /* ! HAVE_TM_GMTOFF */



/* The number of days from the first day of the first ISO week of this
   year to the year day YDAY with week day WDAY.  ISO weeks start on
   Monday; the first ISO week has the year's first Thursday.  YDAY may
   be as small as YDAY_MINIMUM.  */
#define ISO_WEEK_START_WDAY 1 /* Monday */
#define ISO_WEEK1_WDAY 4 /* Thursday */
#define YDAY_MINIMUM (-366)
#ifdef __GNUC__
__inline__
#endif
static int
iso_week_days (int yday, int wday)
{
  /* Add enough to the first operand of % to make it nonnegative.  */
  int big_enough_multiple_of_7 = (-YDAY_MINIMUM / 7 + 2) * 7;
  return (yday
	  - (yday - wday + ISO_WEEK1_WDAY + big_enough_multiple_of_7) % 7
	  + ISO_WEEK1_WDAY - ISO_WEEK_START_WDAY);
}


#if !(defined _NL_CURRENT || HAVE_STRFTIME)
static CHAR_T const weekday_name[][10] =
  {
    L_("Sunday"), L_("Monday"), L_("Tuesday"), L_("Wednesday"),
    L_("Thursday"), L_("Friday"), L_("Saturday")
  };
static CHAR_T const month_name[][10] =
  {
    L_("January"), L_("February"), L_("March"), L_("April"), L_("May"),
    L_("June"), L_("July"), L_("August"), L_("September"), L_("October"),
    L_("November"), L_("December")
  };
#endif


/* When compiling this file, GNU applications can #define my_strftime
   to a symbol (typically nstrftime) to get an extended strftime with
   extra arguments UT and NS.  Emacs is a special case for now, but
   this Emacs-specific code can be removed once Emacs's config.h
   defines my_strftime.  */
#if defined emacs && !defined my_strftime
# define my_strftime nstrftime
#endif

#ifdef my_strftime
# define extra_args , ut, ns
# define extra_args_spec , int ut, int ns
#else
# ifdef COMPILE_WIDE
#  define my_strftime wcsftime
#  define nl_get_alt_digit _nl_get_walt_digit
# else
#  define my_strftime strftime
#  define nl_get_alt_digit _nl_get_alt_digit
# endif
# define extra_args
# define extra_args_spec
/* We don't have this information in general.  */
# define ut 0
# define ns 0
#endif


/* Write information from TP into S according to the format
   string FORMAT, writing no more that MAXSIZE characters
   (including the terminating '\0') and returning number of
   characters written.  If S is NULL, nothing will be written
   anywhere, so to determine how many characters would be
   written, use NULL for S and (size_t) -1 for MAXSIZE.  */
size_t
my_strftime (CHAR_T *s, size_t maxsize, const CHAR_T *format,
	     const struct tm *tp extra_args_spec LOCALE_PARAM_PROTO)
{
#if defined _LIBC && defined USE_IN_EXTENDED_LOCALE_MODEL
  struct locale_data *const current = loc->__locales[LC_TIME];
#endif

  int hour12 = tp->tm_hour;
#ifdef _NL_CURRENT
  /* We cannot make the following values variables since we must delay
     the evaluation of these values until really needed since some
     expressions might not be valid in every situation.  The `struct tm'
     might be generated by a strptime() call that initialized
     only a few elements.  Dereference the pointers only if the format
     requires this.  Then it is ok to fail if the pointers are invalid.  */
# define a_wkday \
  ((const CHAR_T *) _NL_CURRENT (LC_TIME, NLW(ABDAY_1) + tp->tm_wday))
# define f_wkday \
  ((const CHAR_T *) _NL_CURRENT (LC_TIME, NLW(DAY_1) + tp->tm_wday))
# define a_month \
  ((const CHAR_T *) _NL_CURRENT (LC_TIME, NLW(ABMON_1) + tp->tm_mon))
# define f_month \
  ((const CHAR_T *) _NL_CURRENT (LC_TIME, NLW(MON_1) + tp->tm_mon))
# define ampm \
  ((const CHAR_T *) _NL_CURRENT (LC_TIME, tp->tm_hour > 11		      \
				 ? NLW(PM_STR) : NLW(AM_STR)))

# define aw_len STRLEN (a_wkday)
# define am_len STRLEN (a_month)
# define ap_len STRLEN (ampm)
#else
# if !HAVE_STRFTIME
#  define f_wkday (weekday_name[tp->tm_wday])
#  define f_month (month_name[tp->tm_mon])
#  define a_wkday f_wkday
#  define a_month f_month
#  define ampm (L_("AMPM") + 2 * (tp->tm_hour > 11))

  size_t aw_len = 3;
  size_t am_len = 3;
  size_t ap_len = 2;
# endif
#endif
  const char *zone;
  size_t i = 0;
  CHAR_T *p = s;
  const CHAR_T *f;
#if DO_MULTIBYTE && !defined COMPILE_WIDE
  const char *format_end = NULL;
#endif

#if ! defined _LIBC && ! HAVE_RUN_TZSET_TEST
  /* Solaris 2.5.x and 2.6 tzset sometimes modify the storage returned
     by localtime.  On such systems, we must either use the tzset and
     localtime wrappers to work around the bug (which sets
     HAVE_RUN_TZSET_TEST) or make a copy of the structure.  */
  struct tm copy = *tp;
  tp = &copy;
#endif

  zone = NULL;
#if HAVE_TM_ZONE
  /* The POSIX test suite assumes that setting
     the environment variable TZ to a new value before calling strftime()
     will influence the result (the %Z format) even if the information in
     TP is computed with a totally different time zone.
     This is bogus: though POSIX allows bad behavior like this,
     POSIX does not require it.  Do the right thing instead.  */
  zone = (const char *) tp->tm_zone;
#endif
#if HAVE_TZNAME
  if (ut)
    {
      if (! (zone && *zone))
	zone = "GMT";
    }
  else
    {
      /* POSIX.1 requires that local time zone information be used as
	 though strftime called tzset.  */
# if HAVE_TZSET
      tzset ();
# endif
    }
#endif

  if (hour12 > 12)
    hour12 -= 12;
  else
    if (hour12 == 0)
      hour12 = 12;

  for (f = format; *f != '\0'; ++f)
    {
      int pad = 0;		/* Padding for number ('-', '_', or 0).  */
      int modifier;		/* Field modifier ('E', 'O', or 0).  */
      int digits;		/* Max digits for numeric format.  */
      int number_value;		/* Numeric value to be printed.  */
      unsigned int u_number_value; /* (unsigned int) number_value.  */
      bool negative_number;	/* 1 if the number is negative.  */
      const CHAR_T *subfmt;
      CHAR_T *bufp;
      CHAR_T buf[1 + (sizeof (int) < sizeof (time_t)
		      ? INT_STRLEN_BOUND (time_t)
		      : INT_STRLEN_BOUND (int))];
      int width = -1;
      bool to_lowcase = false;
      bool to_uppcase = false;
      bool change_case = false;
      int format_char;

#if DO_MULTIBYTE && !defined COMPILE_WIDE
      switch (*f)
	{
	case L_('%'):
	  break;

	case L_('\b'): case L_('\t'): case L_('\n'):
	case L_('\v'): case L_('\f'): case L_('\r'):
	case L_(' '): case L_('!'): case L_('"'): case L_('#'): case L_('&'):
	case L_('\''): case L_('('): case L_(')'): case L_('*'): case L_('+'):
	case L_(','): case L_('-'): case L_('.'): case L_('/'): case L_('0'):
	case L_('1'): case L_('2'): case L_('3'): case L_('4'): case L_('5'):
	case L_('6'): case L_('7'): case L_('8'): case L_('9'): case L_(':'):
	case L_(';'): case L_('<'): case L_('='): case L_('>'): case L_('?'):
	case L_('A'): case L_('B'): case L_('C'): case L_('D'): case L_('E'):
	case L_('F'): case L_('G'): case L_('H'): case L_('I'): case L_('J'):
	case L_('K'): case L_('L'): case L_('M'): case L_('N'): case L_('O'):
	case L_('P'): case L_('Q'): case L_('R'): case L_('S'): case L_('T'):
	case L_('U'): case L_('V'): case L_('W'): case L_('X'): case L_('Y'):
	case L_('Z'): case L_('['): case L_('\\'): case L_(']'): case L_('^'):
	case L_('_'): case L_('a'): case L_('b'): case L_('c'): case L_('d'):
	case L_('e'): case L_('f'): case L_('g'): case L_('h'): case L_('i'):
	case L_('j'): case L_('k'): case L_('l'): case L_('m'): case L_('n'):
	case L_('o'): case L_('p'): case L_('q'): case L_('r'): case L_('s'):
	case L_('t'): case L_('u'): case L_('v'): case L_('w'): case L_('x'):
	case L_('y'): case L_('z'): case L_('{'): case L_('|'): case L_('}'):
	case L_('~'):
	  /* The C Standard requires these 98 characters (plus '%') to
	     be in the basic execution character set.  None of these
	     characters can start a multibyte sequence, so they need
	     not be analyzed further.  */
	  add (1, *p = *f);
	  continue;

	default:
	  /* Copy this multibyte sequence until we reach its end, find
	     an error, or come back to the initial shift state.  */
	  {
	    mbstate_t mbstate = mbstate_zero;
	    size_t len = 0;
	    size_t fsize;

	    if (! format_end)
	      format_end = f + strlen (f) + 1;
	    fsize = format_end - f;

	    do
	      {
		size_t bytes = mbrlen (f + len, fsize - len, &mbstate);

		if (bytes == 0)
		  break;

		if (bytes == (size_t) -2)
		  {
		    len += strlen (f + len);
		    break;
		  }

		if (bytes == (size_t) -1)
		  {
		    len++;
		    break;
		  }

		len += bytes;
	      }
	    while (! mbsinit (&mbstate));

	    cpy (len, f);
	    f += len - 1;
	    continue;
	  }
	}

#else /* ! DO_MULTIBYTE */

      /* Either multibyte encodings are not supported, they are
	 safe for formats, so any non-'%' byte can be copied through,
	 or this is the wide character version.  */
      if (*f != L_('%'))
	{
	  add (1, *p = *f);
	  continue;
	}

#endif /* ! DO_MULTIBYTE */

      /* Check for flags that can modify a format.  */
      while (1)
	{
	  switch (*++f)
	    {
	      /* This influences the number formats.  */
	    case L_('_'):
	    case L_('-'):
	    case L_('0'):
	      pad = *f;
	      continue;

	      /* This changes textual output.  */
	    case L_('^'):
	      to_uppcase = true;
	      continue;
	    case L_('#'):
	      change_case = true;
	      continue;

	    default:
	      break;
	    }
	  break;
	}

      /* As a GNU extension we allow to specify the field width.  */
      if (ISDIGIT (*f))
	{
	  width = 0;
	  do
	    {
	      if (width > INT_MAX / 10
		  || (width == INT_MAX / 10 && *f - L_('0') > INT_MAX % 10))
		/* Avoid overflow.  */
		width = INT_MAX;
	      else
		{
		  width *= 10;
		  width += *f - L_('0');
		}
	      ++f;
	    }
	  while (ISDIGIT (*f));
	}

      /* Check for modifiers.  */
      switch (*f)
	{
	case L_('E'):
	case L_('O'):
	  modifier = *f++;
	  break;

	default:
	  modifier = 0;
	  break;
	}

      /* Now do the specified format.  */
      format_char = *f;
      switch (format_char)
	{
#define DO_NUMBER(d, v) \
	  digits = d;							      \
	  number_value = v; goto do_number
#define DO_SIGNED_NUMBER(d, negative, v) \
	  digits = d;							      \
	  negative_number = negative;					      \
	  u_number_value = v; goto do_signed_number
#define DO_NUMBER_SPACEPAD(d, v) \
	  digits = d;							      \
	  number_value = v; goto do_number_spacepad

	case L_('%'):
	  if (modifier != 0)
	    goto bad_format;
	  add (1, *p = *f);
	  break;

	case L_('a'):
	  if (modifier != 0)
	    goto bad_format;
	  if (change_case)
	    {
	      to_uppcase = true;
	      to_lowcase = false;
	    }
#if defined _NL_CURRENT || !HAVE_STRFTIME
	  cpy (aw_len, a_wkday);
	  break;
#else
	  goto underlying_strftime;
#endif

	case 'A':
	  if (modifier != 0)
	    goto bad_format;
	  if (change_case)
	    {
	      to_uppcase = true;
	      to_lowcase = false;
	    }
#if defined _NL_CURRENT || !HAVE_STRFTIME
	  cpy (STRLEN (f_wkday), f_wkday);
	  break;
#else
	  goto underlying_strftime;
#endif

	case L_('b'):
	case L_('h'):
	  if (change_case)
	    {
	      to_uppcase = true;
	      to_lowcase = false;
	    }
	  if (modifier != 0)
	    goto bad_format;
#if defined _NL_CURRENT || !HAVE_STRFTIME
	  cpy (am_len, a_month);
	  break;
#else
	  goto underlying_strftime;
#endif

	case L_('B'):
	  if (modifier != 0)
	    goto bad_format;
	  if (change_case)
	    {
	      to_uppcase = true;
	      to_lowcase = false;
	    }
#if defined _NL_CURRENT || !HAVE_STRFTIME
	  cpy (STRLEN (f_month), f_month);
	  break;
#else
	  goto underlying_strftime;
#endif

	case L_('c'):
	  if (modifier == L_('O'))
	    goto bad_format;
#ifdef _NL_CURRENT
	  if (! (modifier == 'E'
		 && (*(subfmt =
		       (const CHAR_T *) _NL_CURRENT (LC_TIME,
						     NLW(ERA_D_T_FMT)))
		     != '\0')))
	    subfmt = (const CHAR_T *) _NL_CURRENT (LC_TIME, NLW(D_T_FMT));
#else
# if HAVE_STRFTIME
	  goto underlying_strftime;
# else
	  subfmt = L_("%a %b %e %H:%M:%S %Y");
# endif
#endif

	subformat:
	  {
	    CHAR_T *old_start = p;
	    size_t len = my_strftime (NULL, (size_t) -1, subfmt,
				      tp extra_args LOCALE_ARG);
	    add (len, my_strftime (p, maxsize - i, subfmt,
				   tp extra_args LOCALE_ARG));

	    if (to_uppcase)
	      while (old_start < p)
		{
		  *old_start = TOUPPER ((UCHAR_T) *old_start, loc);
		  ++old_start;
		}
	  }
	  break;

#if HAVE_STRFTIME && ! (defined _NL_CURRENT && HAVE_STRUCT_ERA_ENTRY)
	underlying_strftime:
	  {
	    /* The relevant information is available only via the
	       underlying strftime implementation, so use that.  */
	    char ufmt[5];
	    char *u = ufmt;
	    char ubuf[1024]; /* enough for any single format in practice */
	    size_t len;
	    /* Make sure we're calling the actual underlying strftime.
	       In some cases, config.h contains something like
	       "#define strftime rpl_strftime".  */
# ifdef strftime
#  undef strftime
	    size_t strftime ();
# endif

	    /* The space helps distinguish strftime failure from empty
	       output.  */
	    *u++ = ' ';
	    *u++ = '%';
	    if (modifier != 0)
	      *u++ = modifier;
	    *u++ = format_char;
	    *u = '\0';
	    len = strftime (ubuf, sizeof ubuf, ufmt, tp);
	    if (len != 0)
	      cpy (len - 1, ubuf + 1);
	  }
	  break;
#endif

	case L_('C'):
	  if (modifier == L_('O'))
	    goto bad_format;
	  if (modifier == L_('E'))
	    {
#if HAVE_STRUCT_ERA_ENTRY
	      struct era_entry *era = _nl_get_era_entry (tp HELPER_LOCALE_ARG);
	      if (era)
		{
# ifdef COMPILE_WIDE
		  size_t len = __wcslen (era->era_wname);
		  cpy (len, era->era_wname);
# else
		  size_t len = strlen (era->era_name);
		  cpy (len, era->era_name);
# endif
		  break;
		}
#else
# if HAVE_STRFTIME
	      goto underlying_strftime;
# endif
#endif
	    }

	  {
	    int century = tp->tm_year / 100 + TM_YEAR_BASE / 100;
	    century -= tp->tm_year % 100 < 0 && 0 < century;
	    DO_SIGNED_NUMBER (2, tp->tm_year < - TM_YEAR_BASE, century);
	  }

	case L_('x'):
	  if (modifier == L_('O'))
	    goto bad_format;
#ifdef _NL_CURRENT
	  if (! (modifier == L_('E')
		 && (*(subfmt =
		       (const CHAR_T *)_NL_CURRENT (LC_TIME, NLW(ERA_D_FMT)))
		     != L_('\0'))))
	    subfmt = (const CHAR_T *) _NL_CURRENT (LC_TIME, NLW(D_FMT));
	  goto subformat;
#else
# if HAVE_STRFTIME
	  goto underlying_strftime;
# else
	  /* Fall through.  */
# endif
#endif
	case L_('D'):
	  if (modifier != 0)
	    goto bad_format;
	  subfmt = L_("%m/%d/%y");
	  goto subformat;

	case L_('d'):
	  if (modifier == L_('E'))
	    goto bad_format;

	  DO_NUMBER (2, tp->tm_mday);

	case L_('e'):
	  if (modifier == L_('E'))
	    goto bad_format;

	  DO_NUMBER_SPACEPAD (2, tp->tm_mday);

	  /* All numeric formats set DIGITS and NUMBER_VALUE (or U_NUMBER_VALUE)
	     and then jump to one of these three labels.  */

	do_number_spacepad:
	  /* Force `_' flag unless overridden by `0' or `-' flag.  */
	  if (pad != L_('0') && pad != L_('-'))
	    pad = L_('_');

	do_number:
	  /* Format NUMBER_VALUE according to the MODIFIER flag.  */
	  negative_number = number_value < 0;
	  u_number_value = number_value;

	do_signed_number:
	  /* Format U_NUMBER_VALUE according to the MODIFIER flag.
	     NEGATIVE_NUMBER is nonzero if the original number was
	     negative; in this case it was converted directly to
	     unsigned int (i.e., modulo (UINT_MAX + 1)) without
	     negating it.  */
	  if (modifier == L_('O') && !negative_number)
	    {
#ifdef _NL_CURRENT
	      /* Get the locale specific alternate representation of
		 the number.  If none exist NULL is returned.  */
	      const CHAR_T *cp = nl_get_alt_digit (u_number_value
						   HELPER_LOCALE_ARG);

	      if (cp != NULL)
		{
		  size_t digitlen = STRLEN (cp);
		  if (digitlen != 0)
		    {
		      cpy (digitlen, cp);
		      break;
		    }
		}
#else
# if HAVE_STRFTIME
	      goto underlying_strftime;
# endif
#endif
	    }

	  bufp = buf + sizeof (buf) / sizeof (buf[0]);

	  if (negative_number)
	    u_number_value = - u_number_value;

	  do
	    {
	      *--bufp = u_number_value % 10 + L_('0');
	      u_number_value /= 10;
	    }
	  while (u_number_value != 0);

	do_number_sign_and_padding:
	  if (digits < width)
	    digits = width;

	  if (negative_number)
	    *--bufp = L_('-');

	  if (pad != L_('-'))
	    {
	      int padding = digits - (buf + (sizeof (buf) / sizeof (buf[0]))
				      - bufp);

	      if (padding > 0)
		{
		  if (pad == L_('_'))
		    {
		      if ((size_t) padding >= maxsize - i)
			return 0;

		      if (p)
			memset_space (p, padding);
		      i += padding;
		      width = width > padding ? width - padding : 0;
		    }
		  else
		    {
		      if ((size_t) digits >= maxsize - i)
			return 0;

		      if (negative_number)
			{
			  ++bufp;

			  if (p)
			    *p++ = L_('-');
			  ++i;
			}

		      if (p)
			memset_zero (p, padding);
		      i += padding;
		      width = 0;
		    }
		}
	    }

	  cpy (buf + sizeof (buf) / sizeof (buf[0]) - bufp, bufp);
	  break;

	case L_('F'):
	  if (modifier != 0)
	    goto bad_format;
	  subfmt = L_("%Y-%m-%d");
	  goto subformat;

	case L_('H'):
	  if (modifier == L_('E'))
	    goto bad_format;

	  DO_NUMBER (2, tp->tm_hour);

	case L_('I'):
	  if (modifier == L_('E'))
	    goto bad_format;

	  DO_NUMBER (2, hour12);

	case L_('k'):		/* GNU extension.  */
	  if (modifier == L_('E'))
	    goto bad_format;

	  DO_NUMBER_SPACEPAD (2, tp->tm_hour);

	case L_('l'):		/* GNU extension.  */
	  if (modifier == L_('E'))
	    goto bad_format;

	  DO_NUMBER_SPACEPAD (2, hour12);

	case L_('j'):
	  if (modifier == L_('E'))
	    goto bad_format;

	  DO_SIGNED_NUMBER (3, tp->tm_yday < -1, tp->tm_yday + 1U);

	case L_('M'):
	  if (modifier == L_('E'))
	    goto bad_format;

	  DO_NUMBER (2, tp->tm_min);

	case L_('m'):
	  if (modifier == L_('E'))
	    goto bad_format;

	  DO_SIGNED_NUMBER (2, tp->tm_mon < -1, tp->tm_mon + 1U);

#ifndef _LIBC
	case L_('N'):		/* GNU extension.  */
	  if (modifier == L_('E'))
	    goto bad_format;

	  number_value = ns;
	  if (width != -1)
	    {
	      /* Take an explicit width less than 9 as a precision.  */
	      int j;
	      for (j = width; j < 9; j++)
		number_value /= 10;
	    }

	  DO_NUMBER (9, number_value);
#endif

	case L_('n'):
	  add (1, *p = L_('\n'));
	  break;

	case L_('P'):
	  to_lowcase = true;
#if !defined _NL_CURRENT && HAVE_STRFTIME
	  format_char = L_('p');
#endif
	  /* FALLTHROUGH */

	case L_('p'):
	  if (change_case)
	    {
	      to_uppcase = false;
	      to_lowcase = true;
	    }
#if defined _NL_CURRENT || !HAVE_STRFTIME
	  cpy (ap_len, ampm);
	  break;
#else
	  goto underlying_strftime;
#endif

	case L_('R'):
	  subfmt = L_("%H:%M");
	  goto subformat;

	case L_('r'):
#if !defined _NL_CURRENT && HAVE_STRFTIME
	  goto underlying_strftime;
#else
# ifdef _NL_CURRENT
	  if (*(subfmt = (const CHAR_T *) _NL_CURRENT (LC_TIME,
						       NLW(T_FMT_AMPM)))
	      == L_('\0'))
# endif
	    subfmt = L_("%I:%M:%S %p");
	  goto subformat;
#endif

	case L_('S'):
	  if (modifier == L_('E'))
	    goto bad_format;

	  DO_NUMBER (2, tp->tm_sec);

	case L_('s'):		/* GNU extension.  */
	  {
	    struct tm ltm;
	    time_t t;

	    ltm = *tp;
	    t = mktime (&ltm);

	    /* Generate string value for T using time_t arithmetic;
	       this works even if sizeof (long) < sizeof (time_t).  */

	    bufp = buf + sizeof (buf) / sizeof (buf[0]);
	    negative_number = t < 0;

	    do
	      {
		int d = t % 10;
		t /= 10;
		*--bufp = (negative_number ? -d : d) + L_('0');
	      }
	    while (t != 0);

	    digits = 1;
	    goto do_number_sign_and_padding;
	  }

	case L_('X'):
	  if (modifier == L_('O'))
	    goto bad_format;
#ifdef _NL_CURRENT
	  if (! (modifier == L_('E')
		 && (*(subfmt =
		       (const CHAR_T *) _NL_CURRENT (LC_TIME, NLW(ERA_T_FMT)))
		     != L_('\0'))))
	    subfmt = (const CHAR_T *) _NL_CURRENT (LC_TIME, NLW(T_FMT));
	  goto subformat;
#else
# if HAVE_STRFTIME
	  goto underlying_strftime;
# else
	  /* Fall through.  */
# endif
#endif
	case L_('T'):
	  subfmt = L_("%H:%M:%S");
	  goto subformat;

	case L_('t'):
	  add (1, *p = L_('\t'));
	  break;

	case L_('u'):
	  DO_NUMBER (1, (tp->tm_wday - 1 + 7) % 7 + 1);

	case L_('U'):
	  if (modifier == L_('E'))
	    goto bad_format;

	  DO_NUMBER (2, (tp->tm_yday - tp->tm_wday + 7) / 7);

	case L_('V'):
	case L_('g'):
	case L_('G'):
	  if (modifier == L_('E'))
	    goto bad_format;
	  {
	    /* YEAR is a leap year if and only if (tp->tm_year + TM_YEAR_BASE)
	       is a leap year, except that YEAR and YEAR - 1 both work
	       correctly even when (tp->tm_year + TM_YEAR_BASE) would
	       overflow.  */
	    int year = (tp->tm_year
			+ (tp->tm_year < 0
			   ? TM_YEAR_BASE % 400
			   : TM_YEAR_BASE % 400 - 400));
	    int year_adjust = 0;
	    int days = iso_week_days (tp->tm_yday, tp->tm_wday);

	    if (days < 0)
	      {
		/* This ISO week belongs to the previous year.  */
		year_adjust = -1;
		days = iso_week_days (tp->tm_yday + (365 + __isleap (year - 1)),
				      tp->tm_wday);
	      }
	    else
	      {
		int d = iso_week_days (tp->tm_yday - (365 + __isleap (year)),
				       tp->tm_wday);
		if (0 <= d)
		  {
		    /* This ISO week belongs to the next year.  */
		    year_adjust = 1;
		    days = d;
		  }
	      }

	    switch (*f)
	      {
	      case L_('g'):
		{
		  int yy = (tp->tm_year % 100 + year_adjust) % 100;
		  DO_NUMBER (2, (0 <= yy
				 ? yy
				 : tp->tm_year < -TM_YEAR_BASE - year_adjust
				 ? -yy
				 : yy + 100));
		}

	      case L_('G'):
		DO_SIGNED_NUMBER (4, tp->tm_year < -TM_YEAR_BASE - year_adjust,
				  (tp->tm_year + (unsigned int) TM_YEAR_BASE
				   + year_adjust));

	      default:
		DO_NUMBER (2, days / 7 + 1);
	      }
	  }

	case L_('W'):
	  if (modifier == L_('E'))
	    goto bad_format;

	  DO_NUMBER (2, (tp->tm_yday - (tp->tm_wday - 1 + 7) % 7 + 7) / 7);

	case L_('w'):
	  if (modifier == L_('E'))
	    goto bad_format;

	  DO_NUMBER (1, tp->tm_wday);

	case L_('Y'):
	  if (modifier == 'E')
	    {
#if HAVE_STRUCT_ERA_ENTRY
	      struct era_entry *era = _nl_get_era_entry (tp HELPER_LOCALE_ARG);
	      if (era)
		{
# ifdef COMPILE_WIDE
		  subfmt = era->era_wformat;
# else
		  subfmt = era->era_format;
# endif
		  goto subformat;
		}
#else
# if HAVE_STRFTIME
	      goto underlying_strftime;
# endif
#endif
	    }
	  if (modifier == L_('O'))
	    goto bad_format;
	  else
	    DO_SIGNED_NUMBER (4, tp->tm_year < -TM_YEAR_BASE,
			      tp->tm_year + (unsigned int) TM_YEAR_BASE);

	case L_('y'):
	  if (modifier == L_('E'))
	    {
#if HAVE_STRUCT_ERA_ENTRY
	      struct era_entry *era = _nl_get_era_entry (tp HELPER_LOCALE_ARG);
	      if (era)
		{
		  int delta = tp->tm_year - era->start_date[0];
		  DO_NUMBER (1, (era->offset
				 + delta * era->absolute_direction));
		}
#else
# if HAVE_STRFTIME
	      goto underlying_strftime;
# endif
#endif
	    }

	  {
	    int yy = tp->tm_year % 100;
	    if (yy < 0)
	      yy = tp->tm_year < - TM_YEAR_BASE ? -yy : yy + 100;
	    DO_NUMBER (2, yy);
	  }

	case L_('Z'):
	  if (change_case)
	    {
	      to_uppcase = false;
	      to_lowcase = true;
	    }

#if HAVE_TZNAME
	  /* The tzset() call might have changed the value.  */
	  if (!(zone && *zone) && tp->tm_isdst >= 0)
	    zone = tzname[tp->tm_isdst != 0];
#endif
	  if (! zone)
	    zone = "";

#ifdef COMPILE_WIDE
	  {
	    /* The zone string is always given in multibyte form.  We have
	       to transform it first.  */
	    wchar_t *wczone;
	    size_t len;
	    widen (zone, wczone, len);
	    cpy (len, wczone);
	  }
#else
	  cpy (strlen (zone), zone);
#endif
	  break;

	case L_('z'):
	  if (tp->tm_isdst < 0)
	    break;

	  {
	    int diff;
#if HAVE_TM_GMTOFF
	    diff = tp->tm_gmtoff;
#else
	    if (ut)
	      diff = 0;
	    else
	      {
		struct tm gtm;
		struct tm ltm;
		time_t lt;

		ltm = *tp;
		lt = mktime (&ltm);

		if (lt == (time_t) -1)
		  {
		    /* mktime returns -1 for errors, but -1 is also a
		       valid time_t value.  Check whether an error really
		       occurred.  */
		    struct tm tm;

		    if (! __localtime_r (&lt, &tm)
			|| ((ltm.tm_sec ^ tm.tm_sec)
			    | (ltm.tm_min ^ tm.tm_min)
			    | (ltm.tm_hour ^ tm.tm_hour)
			    | (ltm.tm_mday ^ tm.tm_mday)
			    | (ltm.tm_mon ^ tm.tm_mon)
			    | (ltm.tm_year ^ tm.tm_year)))
		      break;
		  }

		if (! __gmtime_r (&lt, &gtm))
		  break;

		diff = tm_diff (&ltm, &gtm);
	      }
#endif

	    if (diff < 0)
	      {
		add (1, *p = L_('-'));
		diff = -diff;
	      }
	    else
	      add (1, *p = L_('+'));

	    diff /= 60;
	    DO_NUMBER (4, (diff / 60) * 100 + diff % 60);
	  }

	case L_('\0'):		/* GNU extension: % at end of format.  */
	    --f;
	    /* Fall through.  */
	default:
	  /* Unknown format; output the format, including the '%',
	     since this is most likely the right thing to do if a
	     multibyte string has been misparsed.  */
	bad_format:
	  {
	    int flen;
	    for (flen = 1; f[1 - flen] != L_('%'); flen++)
	      continue;
	    cpy (flen, &f[1 - flen]);
	  }
	  break;
	}
    }

  if (p && maxsize != 0)
    *p = L_('\0');
  return i;
}
#ifdef _LIBC
libc_hidden_def (my_strftime)
#endif


#ifdef emacs
/* For Emacs we have a separate interface which corresponds to the normal
   strftime function plus the ut argument, but without the ns argument.  */
size_t
emacs_strftimeu (char *s, size_t maxsize, const char *format,
		 const struct tm *tp, int ut)
{
  return my_strftime (s, maxsize, format, tp, ut, 0);
}
#endif