(strftime): New version, from GNU libc.

1 files changed, 523 insertions, 180 deletions

diff --git a/lib/strftime.c b/lib/strftime.c
index abcae166c..aa97c02ce 100644
--- a/lib/strftime.c
+++ b/lib/strftime.c
@@ -1,22 +1,20 @@
 /* Copyright (C) 1991, 92, 93, 94, 95, 96 Free Software Foundation, Inc.
+This file is part of the GNU C Library.
 
-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.
+The GNU C Library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Library General Public License as
+published by the Free Software Foundation; either version 2 of the
+License, or (at your option) any later version.
 
-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,
+The GNU C Library 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.
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Library 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
-USA.  */
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB.  If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA.  */
 
 #ifdef HAVE_CONFIG_H
 # include <config.h>
@@ -25,13 +23,15 @@ USA.  */
 #ifdef _LIBC
 # define HAVE_LIMITS_H 1
 # define HAVE_MBLEN 1
+# define HAVE_MBRLEN 1
+# define HAVE_TM_GMTOFF 1
 # define HAVE_TM_ZONE 1
+# define MULTIBYTE_IS_FORMAT_SAFE 1
 # define STDC_HEADERS 1
 # include <ansidecl.h>
 # include "../locale/localeinfo.h"
 #endif
 
-#include <stdio.h>
 #include <sys/types.h>		/* Some systems define `time_t' here.  */
 
 #ifdef TIME_WITH_SYS_TIME
@@ -45,8 +45,24 @@ USA.  */
 # endif
 #endif
 
-#if HAVE_MBLEN
-# include <ctype.h>
+/* 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 && ! 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
 
 #if HAVE_LIMITS_H
@@ -77,11 +93,68 @@ USA.  */
 #endif
 #endif
 
-/* Uncomment following line in the production version.  */
-/* #define NDEBUG */
-#include <assert.h>
+#ifndef CHAR_BIT
+#define CHAR_BIT 8
+#endif
+
+#define TYPE_SIGNED(t) ((t) -1 < 0)
 
-static unsigned int week __P ((const struct tm *const, int, int));
+/* Bound on length of the string representing an integer value of type t.
+   Subtract one for the sign bit if t is signed;
+   302 / 1000 is log10 (2) rounded up;
+   add one for integer division truncation;
+   add one more for a minus sign if t is signed.  */
+#define INT_STRLEN_BOUND(t) \
+  ((sizeof (t) * CHAR_BIT - TYPE_SIGNED (t)) * 302 / 100 + 1 + TYPE_SIGNED (t))
+
+#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 gmtime_r __gmtime_r
+# define localtime_r __localtime_r
+#else
+# if ! HAVE_LOCALTIME_R
+#  if ! HAVE_TM_GMTOFF
+/* Approximate gmtime_r as best we can in its absence.  */
+#define gmtime_r my_gmtime_r
+static struct tm *gmtime_r __P ((const time_t *, struct tm *));
+static struct tm *
+gmtime_r (t, tp)
+     const time_t *t;
+     struct tm *tp;
+{
+  struct tm *l = gmtime (t);
+  if (! l)
+    return 0;
+  *tp = *l;
+  return tp;
+}
+#  endif /* ! HAVE_TM_GMTOFF */
+
+/* Approximate localtime_r as best we can in its absence.  */
+#define localtime_r my_localtime_r
+static struct tm *localtime_r __P ((const time_t *, struct tm *));
+static struct tm *
+localtime_r (t, tp)
+     const time_t *t;
+     struct tm *tp;
+{
+  struct tm *l = localtime (t);
+  if (! l)
+    return 0;
+  *tp = *l;
+  return tp;
+}
+# endif /* ! HAVE_LOCALTIME_R */
+#endif /* ! defined (_LIBC) */
 
 
 #define	add(n, f)							      \
@@ -99,53 +172,57 @@ static unsigned int week __P ((const struct tm *const, int, int));
     } while (0)
 #define	cpy(n, s)	add ((n), memcpy((PTR) p, (PTR) (s), (n)))
 
-#ifdef _LIBC
-#define	fmt(n, args)	add((n), if (sprintf args != (n)) return 0)
-#else
-#define	fmt(n, args)	add((n), sprintf args; if (strlen (p) != (n)) return 0)
-#endif
+#if ! HAVE_TM_GMTOFF
+/* Yield the difference between *A and *B,
+   measured in seconds, ignoring leap seconds.  */
+static int tm_diff __P ((const struct tm *, const struct tm *));
+static int
+tm_diff (a, b)
+     const struct tm *a;
+     const struct tm *b;
+{
+  int ay = a->tm_year + TM_YEAR_BASE - 1;
+  int by = b->tm_year + TM_YEAR_BASE - 1;
+  /* Divide years by 100, rounding towards minus infinity.  */
+  int ac = ay / 100 - (ay % 100 < 0);
+  int bc = by / 100 - (by % 100 < 0);
+  int intervening_leap_days =
+    ((ay >> 2) - (by >> 2)) - (ac - bc) + ((ac >> 2) - (bc >> 2));
+  int years = ay - by;
+  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 */
 
 
 
-/* Return the week in the year specified by TP,
-   with weeks starting on STARTING_DAY.  */
-#ifdef	__GNUC__
+/* 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)
+static int iso_week_days __P ((int, int));
+#ifdef __GNUC__
 inline
 #endif
-static unsigned int
-week (tp, starting_day, max_preceding)
-      const struct tm *const tp;
-      int starting_day;
-      int max_preceding;
+static int
+iso_week_days (yday, wday)
+     int yday;
+     int wday;
 {
-  int wday, dl, base;
-
-  wday = tp->tm_wday - starting_day;
-  if (wday < 0)
-    wday += 7;
-
-  /* Set DL to the day in the year of the first day of the week
-     containing the day specified in TP.  */
-  dl = tp->tm_yday - wday;
-
-  /* For the computation following ISO 8601:1988 we set the number of
-     the week containing January 1st to 1 if this week has more than
-     MAX_PRECEDING days in the new year.  For ISO 8601 this number is
-     3, for the other representation it is 7 (i.e., not to be
-     fulfilled).  */
-  base = ((dl + 7) % 7) > max_preceding ? 1 : 0;
-
-  /* If DL is negative we compute the result as 0 unless we have to
-     compute it according ISO 8601.  In this case we have to return 53
-     or 1 if the week containing January 1st has less than 4 days in
-     the new year or not.  If DL is not negative we calculate the
-     number of complete weeks for our week (DL / 7) plus 1 (because
-     only for DL < 0 we are in week 0/53 and plus the number of the
-     first week computed in the last step.  */
-  return dl < 0 ? (dl < -max_preceding ? 53 : base)
-		: base + 1 + dl / 7;
+  /* 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);
 }
 
+
 #ifndef _NL_CURRENT
 static char const weekday_name[][10] =
   {
@@ -183,6 +260,9 @@ strftime (s, maxsize, format, tp)
   size_t aw_len = strlen(a_wkday);
   size_t am_len = strlen(a_month);
   size_t ap_len = strlen (ampm);
+
+  const char *alt_digits = _NL_CURRENT (LC_TIME, ALT_DIGITS);
+  const char *end_alt_digits = _NL_CURRENT (LC_TIME, ALT_DIGITS + 1);
 #else
   const char *const f_wkday = weekday_name[tp->tm_wday];
   const char *const f_month = month_name[tp->tm_mon];
@@ -195,18 +275,11 @@ strftime (s, maxsize, format, tp)
 #endif
   size_t wkday_len = strlen (f_wkday);
   size_t month_len = strlen (f_month);
-  const unsigned int y_week0 = week (tp, 0, 7);
-  const unsigned int y_week1 = week (tp, 1, 7);
-  const unsigned int y_week2 = week (tp, 1, 3);
   const char *zone;
   size_t zonelen;
   register size_t i = 0;
   register char *p = s;
   register const char *f;
-  char number_fmt[5];
-
-  /* Initialize the buffer we will use for the sprintf format for numbers.  */
-  number_fmt[0] = '%';
 
   zone = 0;
 #if HAVE_TM_ZONE
@@ -216,8 +289,8 @@ strftime (s, maxsize, format, tp)
   if (!(zone && *zone) && tp->tm_isdst >= 0)
     zone = tzname[tp->tm_isdst];
 #endif
-  if (!(zone && *zone))
-    zone = "???";
+  if (! zone)
+    zone = "";		/* POSIX.2 requires the empty string here.  */
 
   zonelen = strlen (zone);
 
@@ -228,78 +301,170 @@ strftime (s, maxsize, format, tp)
 
   for (f = format; *f != '\0'; ++f)
     {
-      enum { pad_zero, pad_space, pad_none } pad; /* Padding for number.  */
-      unsigned int maxdigits;	/* Max digits for numeric format.  */
-      unsigned int number_value; /* Numeric value to be printed.  */
+      int pad;			/* 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.  */
+      int negative_number;	/* 1 if the number is negative.  */
       const char *subfmt;
+      char *bufp;
+      char buf[1 + (sizeof (int) < sizeof (time_t)
+		    ? INT_STRLEN_BOUND (time_t)
+		    : INT_STRLEN_BOUND (int))];
 
-#if HAVE_MBLEN
-      if (!isascii (*f))
+#if DO_MULTIBYTE
+
+       switch (*f)
 	{
-	  /* Non-ASCII, may be a multibyte.  */
-	  int len = mblen (f, strlen (f));
-	  if (len > 0)
-	    {
-	      cpy(len, f);
-	      continue;
-	    }
+	case '%':
+	  break;
+
+	case '\a': case '\b': case '\t': case '\n':
+	case '\v': case '\f': case '\r':
+	case ' ': case '!': case '"': case '#': case '&': case'\'':
+	case '(': case ')': case '*': case '+': case ',': case '-':
+	case '.': case '/': case '0': case '1': case '2': case '3':
+	case '4': case '5': case '6': case '7': case '8': case '9':
+	case ':': case ';': case '<': case '=': case '>': case '?':
+	case 'A': case 'B': case 'C': case 'D': case 'E': case 'F':
+	case 'G': case 'H': case 'I': case 'J': case 'K': case 'L':
+	case 'M': case 'N': case 'O': case 'P': case 'Q': case 'R':
+	case 'S': case 'T': case 'U': case 'V': case 'W': case 'X':
+	case 'Y': case 'Z': case '[': case'\\': case ']': case '^':
+	case '_': case 'a': case 'b': case 'c': case 'd': case 'e':
+	case 'f': case 'g': case 'h': case 'i': case 'j': case 'k':
+	case 'l': case 'm': case 'n': case 'o': case 'p': case 'q':
+	case 'r': case 's': case 't': case 'u': case 'v': case 'w':
+	case 'x': case 'y': case 'z': case '{': case '|': case '}':
+	case '~':
+	  /* 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;
+
+	    do
+	      {
+		size_t bytes = mbrlen (f + len, (size_t) -1, &mbstate);
+
+		if (bytes == 0)
+		  break;
+
+		if (bytes == (size_t) -2 || bytes == (size_t) -1)
+		  {
+		    len++;
+		    break;
+		  }
+
+		len += bytes;
+	      }
+	    while (! mbsinit (&mbstate));
+
+	    cpy (len, f);
+	    continue;
+	  }
 	}
-#endif
 
+#else /* ! DO_MULTIBYTE */
+
+      /* Either multibyte encodings are not supported, or they are
+	 safe for formats, so any non-'%' byte can be copied through.  */
       if (*f != '%')
 	{
 	  add (1, *p = *f);
 	  continue;
 	}
 
+#endif /* ! DO_MULTIBYTE */
+
       /* Check for flags that can modify a number format.  */
       ++f;
       switch (*f)
 	{
 	case '_':
-	  pad = pad_space;
-	  ++f;
-	  break;
 	case '-':
-	  pad = pad_none;
-	  ++f;
+	  pad = *f++;
+	  break;
+
+	default:
+	  pad = 0;
 	  break;
+	}
+
+      /* Check for modifiers.  */
+      switch (*f)
+	{
+	case 'E':
+	case 'O':
+	  modifier = *f++;
+	  break;
+
 	default:
-	  pad = pad_zero;
+	  modifier = 0;
 	  break;
 	}
 
       /* Now do the specified format.  */
       switch (*f)
 	{
-	case '\0':
+#define DO_NUMBER(d, v) \
+	  digits = d; number_value = v; goto do_number
+#define DO_NUMBER_SPACEPAD(d, v) \
+	  digits = d; number_value = v; goto do_number_spacepad
+
+	case '\0':		/* GNU extension: % at end of format.  */
+	    --f;
+	    /* Fall through.  */
 	case '%':
+	  if (modifier != 0)
+	    goto bad_format;
 	  add (1, *p = *f);
 	  break;
 
 	case 'a':
+	  if (modifier != 0)
+	    goto bad_format;
 	  cpy (aw_len, a_wkday);
 	  break;
 
 	case 'A':
+	  if (modifier != 0)
+	    goto bad_format;
 	  cpy (wkday_len, f_wkday);
 	  break;
 
 	case 'b':
-	case 'h':		/* GNU extension.  */
+	case 'h':		/* POSIX.2 extension.  */
+	  if (modifier != 0)
+	    goto bad_format;
 	  cpy (am_len, a_month);
 	  break;
 
 	case 'B':
+	  if (modifier != 0)
+	    goto bad_format;
 	  cpy (month_len, f_month);
 	  break;
 
 	case 'c':
+	  if (modifier == 'O')
+	    goto bad_format;
 #ifdef _NL_CURRENT
-	  subfmt = _NL_CURRENT (LC_TIME, D_T_FMT);
+	  if (! (modifier == 'E'
+		 && *(subfmt = _NL_CURRENT (LC_TIME, ERA_D_T_FMT)) != '\0'))
+	    subfmt = _NL_CURRENT (LC_TIME, D_T_FMT);
 #else
-	  subfmt = "%a %b %d %H:%M:%S %Z %Y";
+	  subfmt = "%a %b %e %H:%M:%S %Z %Y";
 #endif
+
 	subformat:
 	  {
 	    size_t len = strftime (p, maxsize - i, subfmt, tp);
@@ -309,91 +474,163 @@ strftime (s, maxsize, format, tp)
 	  }
 	  break;
 
-#define DO_NUMBER(digits, value) \
-	  maxdigits = digits; number_value = value; goto do_number
-#define DO_NUMBER_SPACEPAD(digits, value) \
-	  maxdigits = digits; number_value = value; goto do_number_spacepad
-
-	case 'C':
-	  DO_NUMBER (2, (1900 + tp->tm_year) / 100);
+	case 'C':		/* POSIX.2 extension.  */
+	  if (modifier == 'O')
+	    goto bad_format;
+#ifdef _NL_CURRENT
+	  /* XXX %EC is not implemented yet.  */
+#endif
+	  {
+	    int year = tp->tm_year + TM_YEAR_BASE;
+	    DO_NUMBER (1, year / 100 - (year % 100 < 0));
+	  }
 
 	case 'x':
+	  if (modifier == 'O')
+	    goto bad_format;
 #ifdef _NL_CURRENT
-	  subfmt = _NL_CURRENT (LC_TIME, D_FMT);
+	  if (! (modifier == 'E'
+		 && *(subfmt = _NL_CURRENT (LC_TIME, ERA_D_FMT)) != '\0'))
+	    subfmt = _NL_CURRENT (LC_TIME, D_FMT);
 	  goto subformat;
 #endif
 	  /* Fall through.  */
-	case 'D':		/* GNU extension.  */
+	case 'D':		/* POSIX.2 extension.  */
+	  if (modifier != 0)
+	    goto bad_format;
 	  subfmt = "%m/%d/%y";
 	  goto subformat;
 
 	case 'd':
+	  if (modifier == 'E')
+	    goto bad_format;
+
 	  DO_NUMBER (2, tp->tm_mday);
 
-	case 'e':		/* GNU extension: %d, but blank-padded.  */
+	case 'e':		/* POSIX.2 extension.  */
+	  if (modifier == 'E')
+	    goto bad_format;
+
 	  DO_NUMBER_SPACEPAD (2, tp->tm_mday);
 
-	  /* All numeric formats set MAXDIGITS and NUMBER_VALUE and then
+	  /* All numeric formats set DIGITS and NUMBER_VALUE and then
 	     jump to one of these two labels.  */
 
 	do_number_spacepad:
 	  /* Force `_' flag.  */
-	  pad = pad_space;
+	  pad = '_';
 
 	do_number:
+	  /* Format the number according to the MODIFIER flag.  */
+
+#ifdef _NL_CURRENT
+	  if (modifier == 'O')
+	    {
+	      /* ALT_DIGITS is the first entry in an array with
+		 alternative digit symbols.  We have to find string
+		 number NUMBER_VALUE, but must not look beyond
+		 END_ALT_DIGITS.  */
+	      int run = number_value;
+	      const char *cp = alt_digits;
+
+	      while (run > 0 && cp < end_alt_digits)
+		cp = strchr (cp, '\0') + 1;
+
+	      if (cp < end_alt_digits)
+		{
+		  size_t digitlen = strlen (cp);
+		  if (digitlen != 0)
+		    {
+		      cpy (digitlen, cp);
+		      break;
+		    }
+		}
+	    }
+#endif
 	  {
-	    /* Format the number according to the PAD flag.  */
+	    unsigned int u = number_value;
 
-	    register char *nf = &number_fmt[1];
-	    int printed = maxdigits;
+	    bufp = buf + sizeof (buf);
+	    negative_number = number_value < 0;
 
-	    switch (pad)
-	      {
-	      case pad_zero:
-		*nf++ = '0';
-	      case pad_space:
-		*nf++ = '0' + maxdigits;
-	      case pad_none:
-		*nf++ = 'u';
-		*nf = '\0';
-	      }
+	    if (negative_number)
+	      u = -u;
 
-#ifdef _LIBC
-	    add (maxdigits, printed = sprintf (p, number_fmt, number_value));
-#else
-	    add (maxdigits, sprintf (p, number_fmt, number_value);
-		 printed = strlen (p));
-#endif
-	    /* Back up if fewer than MAXDIGITS chars written for pad_none.  */
-	    p -= maxdigits - printed;
-	    i -= maxdigits - printed;
+	    do
+	      *--bufp = u % 10 + '0';
+	    while ((u /= 10) != 0);
+  	  }
 
-	    break;
-	  }
+	do_number_sign_and_padding:
+	  if (negative_number)
+	    *--bufp = '-';
+
+	  if (pad != '-')
+	    {
+	      int padding = digits - (buf + sizeof (buf) - bufp);
+
+	      if (pad == '_')
+		{
+		  while (0 < padding--)
+		    *--bufp = ' ';
+		}
+	      else
+		{
+		  bufp += negative_number;
+		  while (0 < padding--)
+		    *--bufp = '0';
+		  if (negative_number)
+		    *--bufp = '-';
+		}
+	    }
+
+	  cpy (buf + sizeof (buf) - bufp, bufp);
+	  break;
 
 
 	case 'H':
+	  if (modifier == 'E')
+	    goto bad_format;
+
 	  DO_NUMBER (2, tp->tm_hour);
 
 	case 'I':
+	  if (modifier == 'E')
+	    goto bad_format;
+
 	  DO_NUMBER (2, hour12);
 
 	case 'k':		/* GNU extension.  */
+	  if (modifier == 'E')
+	    goto bad_format;
+
 	  DO_NUMBER_SPACEPAD (2, tp->tm_hour);
 
 	case 'l':		/* GNU extension.  */
+	  if (modifier == 'E')
+	    goto bad_format;
+
 	  DO_NUMBER_SPACEPAD (2, hour12);
 
 	case 'j':
+	  if (modifier == 'E')
+	    goto bad_format;
+
 	  DO_NUMBER (3, 1 + tp->tm_yday);
 
 	case 'M':
+	  if (modifier == 'E')
+	    goto bad_format;
+
 	  DO_NUMBER (2, tp->tm_min);
 
 	case 'm':
+	  if (modifier == 'E')
+	    goto bad_format;
+
 	  DO_NUMBER (2, tp->tm_mon + 1);
 
-	case 'n':		/* GNU extension.  */
+	case 'n':		/* POSIX.2 extension.  */
 	  add (1, *p = '\n');
 	  break;
 
@@ -405,94 +642,192 @@ strftime (s, maxsize, format, tp)
 	  subfmt = "%H:%M";
 	  goto subformat;
 
-	case 'r':		/* GNU extension.  */
+	case 'r':		/* POSIX.2 extension.  */
+#ifdef _NL_CURRENT
+	  subfmt = _NL_CURRENT (LC_TIME, T_FMT_AMPM);
+#else
 	  subfmt = "%I:%M:%S %p";
+#endif
 	  goto subformat;
 
 	case 'S':
+	  if (modifier == 'E')
+	    return 0;
+
 	  DO_NUMBER (2, tp->tm_sec);
 
 	case 's':		/* GNU extension.  */
-	  {
-	    struct tm writable_tm = *tp;
-	    unsigned long int num = (unsigned long int) mktime (&writable_tm);
-	    /* `3 * sizeof (unsigned long int)' is an approximation of
-	       the size of the decimal representation of NUM, valid
-	       for sizes <= 16.  */
-	    int printed = 3 * sizeof (unsigned long int);
-	    maxdigits = printed;
-	    assert (sizeof (unsigned long int) <= 16);
-#ifdef _LIBC
-	    add (maxdigits, printed = sprintf (p, "%lu", num));
-#else
-	    add (maxdigits, sprintf (p, "%lu", num); printed = strlen (p));
-#endif
-	    /* Back up if fewer than MAXDIGITS chars written for pad_none.  */
-	    p -= maxdigits - printed;
-	    i -= maxdigits - printed;
+  	  {
+	    struct tm ltm = *tp;
+	    time_t 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);
+	    negative_number = t < 0;
+
+	    do
+	      {
+		int d = t % 10;
+		t /= 10;
+
+		if (negative_number)
+		  {
+		    d = -d;
+
+		    /* Adjust if division truncates to minus infinity.  */
+		    if (0 < -1 % 10 && d < 0)
+		      {
+			t++;
+			d += 10;
+		      }
+		  }
+
+		*--bufp = d + '0';
+	      }
+	    while (t != 0);
+
+	    digits = 1;
+	    goto do_number_sign_and_padding;
 	  }
-	break;
 
 	case 'X':
+	  if (modifier == 'O')
+	    goto bad_format;
 #ifdef _NL_CURRENT
-	  subfmt = _NL_CURRENT (LC_TIME, T_FMT);
+	  if (! (modifier == 'E'
+		 && *(subfmt = _NL_CURRENT (LC_TIME, ERA_T_FMT)) != '\0'))
+	    subfmt = _NL_CURRENT (LC_TIME, T_FMT);
 	  goto subformat;
 #endif
 	  /* Fall through.  */
-	case 'T':		/* GNU extension.  */
+	case 'T':		/* POSIX.2 extension.  */
 	  subfmt = "%H:%M:%S";
 	  goto subformat;
 
-	case 't':		/* GNU extension.  */
+	case 't':		/* POSIX.2 extension.  */
 	  add (1, *p = '\t');
 	  break;
 
+	case 'u':		/* POSIX.2 extension.  */
+	  DO_NUMBER (1, (tp->tm_wday - 1 + 7) % 7 + 1);
+
 	case 'U':
-	  DO_NUMBER (2, y_week0);
+	  if (modifier == 'E')
+	    goto bad_format;
+
+	  DO_NUMBER (2, (tp->tm_yday - tp->tm_wday + 7) / 7);
 
 	case 'V':
-	  DO_NUMBER (2, y_week2);
+	case 'g':		/* GNU extension.  */
+	case 'G':		/* GNU extension.  */
+	  if (modifier == 'E')
+	    goto bad_format;
+	  {
+	    int year = tp->tm_year + TM_YEAR_BASE;
+	    int days = iso_week_days (tp->tm_yday, tp->tm_wday);
+
+	    if (days < 0)
+	      {
+		/* This ISO week belongs to the previous year.  */
+		year--;
+		days = iso_week_days (tp->tm_yday + (365 + __isleap (year)),
+				      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++;
+		    days = d;
+		  }
+	      }
+
+	    switch (*f)
+	      {
+	      case 'g':
+		DO_NUMBER (2, (year % 100 + 100) % 100);
+
+	      case 'G':
+		DO_NUMBER (1, year);
+
+	      default:
+		DO_NUMBER (2, days / 7 + 1);
+	      }
+	  }
 
 	case 'W':
-	  DO_NUMBER (2, y_week1);
+	  if (modifier == 'E')
+	    goto bad_format;
+
+	  DO_NUMBER (2, (tp->tm_yday - (tp->tm_wday - 1 + 7) % 7 + 7) / 7);
 
 	case 'w':
-	  DO_NUMBER (2, tp->tm_wday);
+	  if (modifier == 'E')
+	    goto bad_format;
+
+	  DO_NUMBER (1, tp->tm_wday);
 
 	case 'Y':
-	  DO_NUMBER (4, 1900 + tp->tm_year);
+#ifdef _NL_CURRENT
+	  if (modifier == 'E'
+	      && *(subfmt = _NL_CURRENT (LC_TIME, ERA_YEAR)) != '\0')
+	    goto subformat;
+#endif
+	  if (modifier == 'O')
+	    goto bad_format;
+	  else
+	    DO_NUMBER (1, tp->tm_year + TM_YEAR_BASE);
 
 	case 'y':
-	  DO_NUMBER (2, tp->tm_year % 100);
+#ifdef _NL_CURRENT
+	  /* XXX %Ey is not implemented yet.  */
+#endif
+	  DO_NUMBER (2, (tp->tm_year % 100 + 100) % 100);
 
 	case 'Z':
 	  cpy(zonelen, zone);
 	  break;
 
-	case 'z':
+	case 'z':		/* GNU extension.  */
+	  if (tp->tm_isdst < 0)
+	    break;
+
 	  {
-	    struct tm tml = *tp;
-	    time_t t = mktime (&tml);
-	    struct tm tmg;
 	    int diff;
+#if HAVE_TM_GMTOFF
+	    diff = tp->tm_gmtoff;
+#else
+	    struct tm gtm;
+	    struct tm ltm = *tp;
+	    time_t lt = mktime (&ltm);
 
-	    tml = *localtime (&t);	/* Canonicalize the local time.  */
-	    tmg = *gmtime (&t);
-
-	    /* Compute the difference.  */
-	    diff = tml.tm_min - tmg.tm_min;
-	    diff += 60 * (tml.tm_hour - tmg.tm_hour);
-
-	    if (tml.tm_mon != tmg.tm_mon)
+	    if (lt == (time_t) -1)
 	      {
-		/* We assume no timezone differs from UTC by more than
-		   +- 23 hours.  This should be safe.  */
-		if (tmg.tm_mday == 1)
-		  tml.tm_mday = 0;
-		else /* tml.tm_mday == 1 */
-		  tmg.tm_mday = 0;
+		/* mktime returns -1 for errors, but -1 is also a
+		   valid time_t value.  Check whether an error really
+		   occurred.  */
+		struct tm tm;
+		localtime_r (&lt, &tm);
+
+		if ((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;
 	      }
-	    diff += 1440 * (tml.tm_mday - tmg.tm_mday);
+
+	    if (! gmtime_r (&lt, &gtm))
+	      break;
+
+	    diff = tm_diff (&ltm, &gtm);
+#endif
 
 	    if (diff < 0)
 	      {
@@ -502,13 +837,21 @@ strftime (s, maxsize, format, tp)
 	    else
 	      add (1, *p = '+');
 
-	    pad = pad_zero;
-	    DO_NUMBER (4, ((diff / 60) % 24) * 100 + diff % 60);
+	    diff /= 60;
+	    DO_NUMBER (4, (diff / 60) * 100 + diff % 60);
 	  }
 
 	default:
-	  /* Bad format.  */
-	  add (1, *p = *f);
+	  /* 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 = 2; f[1 - flen] != '%'; flen++)
+	      continue;
+	    cpy (flen, &f[1 - flen]);
+	  }
 	  break;
 	}
     }