path: root/time/strptime.c

/* Convert a string representation of time to a time value.
   Copyright (C) 1996-2000, 2001, 2002 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

/* XXX This version of the implementation is not really complete.
   Some of the fields cannot add information alone.  But if seeing
   some of them in the same format (such as year, week and weekday)
   this is enough information for determining the date.  */

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

#include <ctype.h>
#include <langinfo.h>
#include <limits.h>
#include <string.h>
#include <time.h>

#ifdef _LIBC
# include "../locale/localeinfo.h"
#endif


#ifndef __P
# if defined __GNUC__ || (defined __STDC__ && __STDC__)
#  define __P(args) args
# else
#  define __P(args) ()
# endif  /* GCC.  */
#endif  /* Not __P.  */


#if ! HAVE_LOCALTIME_R && ! defined localtime_r
# ifdef _LIBC
#  define localtime_r __localtime_r
# else
/* 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 /* ! _LIBC */
#endif /* ! HAVE_LOCALTIME_R && ! defined (localtime_r) */


#define match_char(ch1, ch2) if (ch1 != ch2) return NULL
#if defined __GNUC__ && __GNUC__ >= 2
# define match_string(cs1, s2) \
  ({ size_t len = strlen (cs1);						      \
     int result = strncasecmp ((cs1), (s2), len) == 0;			      \
     if (result) (s2) += len;						      \
     result; })
#else
/* Oh come on.  Get a reasonable compiler.  */
# define match_string(cs1, s2) \
  (strncasecmp ((cs1), (s2), strlen (cs1)) ? 0 : ((s2) += strlen (cs1), 1))
#endif
/* We intentionally do not use isdigit() for testing because this will
   lead to problems with the wide character version.  */
#define get_number(from, to, n) \
  do {									      \
    int __n = n;							      \
    val = 0;								      \
    while (*rp == ' ')							      \
      ++rp;								      \
    if (*rp < '0' || *rp > '9')						      \
      return NULL;							      \
    do {								      \
      val *= 10;							      \
      val += *rp++ - '0';						      \
    } while (--__n > 0 && val * 10 <= to && *rp >= '0' && *rp <= '9');	      \
    if (val < from || val > to)						      \
      return NULL;							      \
  } while (0)
#ifdef _NL_CURRENT
# define get_alt_number(from, to, n) \
  ({									      \
     __label__ do_normal;						      \
									      \
     if (*decided != raw)						      \
       {								      \
	 val = _nl_parse_alt_digit (&rp HELPER_LOCALE_ARG);		      \
	 if (val == -1 && *decided != loc)				      \
	   {								      \
	     *decided = loc;						      \
	     goto do_normal;						      \
	   }								      \
	if (val < from || val > to)					      \
	  return NULL;							      \
       }								      \
     else								      \
       {								      \
       do_normal:							      \
	 get_number (from, to, n);					      \
       }								      \
    0;									      \
  })
#else
# define get_alt_number(from, to, n) \
  /* We don't have the alternate representation.  */			      \
  get_number(from, to, n)
#endif
#define recursive(new_fmt) \
  (*(new_fmt) != '\0'							      \
   && (rp = strptime_internal (rp, (new_fmt), tm,			      \
			       decided, era_cnt LOCALE_ARG)) != NULL)


#ifdef _LIBC
/* This is defined in locale/C-time.c in the GNU libc.  */
extern const struct locale_data _nl_C_LC_TIME attribute_hidden;

# define weekday_name (&_nl_C_LC_TIME.values[_NL_ITEM_INDEX (DAY_1)].string)
# define ab_weekday_name \
  (&_nl_C_LC_TIME.values[_NL_ITEM_INDEX (ABDAY_1)].string)
# define month_name (&_nl_C_LC_TIME.values[_NL_ITEM_INDEX (MON_1)].string)
# define ab_month_name (&_nl_C_LC_TIME.values[_NL_ITEM_INDEX (ABMON_1)].string)
# define HERE_D_T_FMT (_nl_C_LC_TIME.values[_NL_ITEM_INDEX (D_T_FMT)].string)
# define HERE_D_FMT (_nl_C_LC_TIME.values[_NL_ITEM_INDEX (D_FMT)].string)
# define HERE_AM_STR (_nl_C_LC_TIME.values[_NL_ITEM_INDEX (AM_STR)].string)
# define HERE_PM_STR (_nl_C_LC_TIME.values[_NL_ITEM_INDEX (PM_STR)].string)
# define HERE_T_FMT_AMPM \
  (_nl_C_LC_TIME.values[_NL_ITEM_INDEX (T_FMT_AMPM)].string)
# define HERE_T_FMT (_nl_C_LC_TIME.values[_NL_ITEM_INDEX (T_FMT)].string)

# define strncasecmp(s1, s2, n) __strncasecmp (s1, s2, n)
#else
static char const weekday_name[][10] =
  {
    "Sunday", "Monday", "Tuesday", "Wednesday",
    "Thursday", "Friday", "Saturday"
  };
static char const ab_weekday_name[][4] =
  {
    "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
  };
static char const month_name[][10] =
  {
    "January", "February", "March", "April", "May", "June",
    "July", "August", "September", "October", "November", "December"
  };
static char const ab_month_name[][4] =
  {
    "Jan", "Feb", "Mar", "Apr", "May", "Jun",
    "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
  };
# define HERE_D_T_FMT "%a %b %e %H:%M:%S %Y"
# define HERE_D_FMT "%m/%d/%y"
# define HERE_AM_STR "AM"
# define HERE_PM_STR "PM"
# define HERE_T_FMT_AMPM "%I:%M:%S %p"
# define HERE_T_FMT "%H:%M:%S"

const unsigned short int __mon_yday[2][13] =
  {
    /* Normal years.  */
    { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 },
    /* Leap years.  */
    { 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 }
  };
#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 strptime		__strptime_l
# undef _NL_CURRENT
# define _NL_CURRENT(category, item) \
  (current->values[_NL_ITEM_INDEX (item)].string)
# undef _NL_CURRENT_WORD
# define _NL_CURRENT_WORD(category, item) \
  (current->values[_NL_ITEM_INDEX (item)].word)
# define LOCALE_PARAM , locale
# define LOCALE_ARG , locale
# define LOCALE_PARAM_PROTO , __locale_t locale
# define LOCALE_PARAM_DECL __locale_t locale;
# define HELPER_LOCALE_ARG , current
#else
# define LOCALE_PARAM
# define LOCALE_ARG
# define LOCALE_PARAM_DECL
# define LOCALE_PARAM_PROTO
# ifdef _LIBC
#  define HELPER_LOCALE_ARG , _NL_CURRENT_DATA (LC_TIME)
# else
#  define HELPER_LOCALE_ARG
# endif
#endif


/* Status of lookup: do we use the locale data or the raw data?  */
enum locale_status { not, loc, raw };


#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

/* Compute the day of the week.  */
static void
day_of_the_week (struct tm *tm)
{
  /* We know that January 1st 1970 was a Thursday (= 4).  Compute the
     the difference between this data in the one on TM and so determine
     the weekday.  */
  int corr_year = 1900 + tm->tm_year - (tm->tm_mon < 2);
  int wday = (-473
	      + (365 * (tm->tm_year - 70))
	      + (corr_year / 4)
	      - ((corr_year / 4) / 25) + ((corr_year / 4) % 25 < 0)
	      + (((corr_year / 4) / 25) / 4)
	      + __mon_yday[0][tm->tm_mon]
	      + tm->tm_mday - 1);
  tm->tm_wday = ((wday % 7) + 7) % 7;
}

/* Compute the day of the year.  */
static void
day_of_the_year (struct tm *tm)
{
  tm->tm_yday = (__mon_yday[__isleap (1900 + tm->tm_year)][tm->tm_mon]
		 + (tm->tm_mday - 1));
}


static char *
#ifdef _LIBC
internal_function
#endif
strptime_internal __P ((const char *rp, const char *fmt, struct tm *tm,
			enum locale_status *decided, int era_cnt
			LOCALE_PARAM_PROTO));

static char *
#ifdef _LIBC
internal_function
#endif
strptime_internal (rp, fmt, tm, decided, era_cnt LOCALE_PARAM)
     const char *rp;
     const char *fmt;
     struct tm *tm;
     enum locale_status *decided;
     int era_cnt;
     LOCALE_PARAM_DECL
{
#if defined _LIBC && defined USE_IN_EXTENDED_LOCALE_MODEL
  struct locale_data *const current = locale->__locales[LC_TIME];
#endif

  const char *rp_backup;
  int cnt;
  size_t val;
  int have_I, is_pm;
  int century, want_century;
  int want_era;
  int have_wday, want_xday;
  int have_yday;
  int have_mon, have_mday;
  int have_uweek, have_wweek;
  int week_no;
  size_t num_eras;
  struct era_entry *era;

  have_I = is_pm = 0;
  century = -1;
  want_century = 0;
  want_era = 0;
  era = NULL;
  week_no = 0;

  have_wday = want_xday = have_yday = have_mon = have_mday = have_uweek = 0;
  have_wweek = 0;

  while (*fmt != '\0')
    {
      /* A white space in the format string matches 0 more or white
	 space in the input string.  */
      if (isspace (*fmt))
	{
	  while (isspace (*rp))
	    ++rp;
	  ++fmt;
	  continue;
	}

      /* Any character but `%' must be matched by the same character
	 in the iput string.  */
      if (*fmt != '%')
	{
	  match_char (*fmt++, *rp++);
	  continue;
	}

      ++fmt;
#ifndef _NL_CURRENT
      /* We need this for handling the `E' modifier.  */
    start_over:
#endif

      /* Make back up of current processing pointer.  */
      rp_backup = rp;

      switch (*fmt++)
	{
	case '%':
	  /* Match the `%' character itself.  */
	  match_char ('%', *rp++);
	  break;
	case 'a':
	case 'A':
	  /* Match day of week.  */
	  for (cnt = 0; cnt < 7; ++cnt)
	    {
#ifdef _NL_CURRENT
	      if (*decided !=raw)
		{
		  if (match_string (_NL_CURRENT (LC_TIME, DAY_1 + cnt), rp))
		    {
		      if (*decided == not
			  && strcmp (_NL_CURRENT (LC_TIME, DAY_1 + cnt),
				     weekday_name[cnt]))
			*decided = loc;
		      break;
		    }
		  if (match_string (_NL_CURRENT (LC_TIME, ABDAY_1 + cnt), rp))
		    {
		      if (*decided == not
			  && strcmp (_NL_CURRENT (LC_TIME, ABDAY_1 + cnt),
				     ab_weekday_name[cnt]))
			*decided = loc;
		      break;
		    }
		}
#endif
	      if (*decided != loc
		  && (match_string (weekday_name[cnt], rp)
		      || match_string (ab_weekday_name[cnt], rp)))
		{
		  *decided = raw;
		  break;
		}
	    }
	  if (cnt == 7)
	    /* Does not match a weekday name.  */
	    return NULL;
	  tm->tm_wday = cnt;
	  have_wday = 1;
	  break;
	case 'b':
	case 'B':
	case 'h':
	  /* Match month name.  */
	  for (cnt = 0; cnt < 12; ++cnt)
	    {
#ifdef _NL_CURRENT
	      if (*decided !=raw)
		{
		  if (match_string (_NL_CURRENT (LC_TIME, MON_1 + cnt), rp))
		    {
		      if (*decided == not
			  && strcmp (_NL_CURRENT (LC_TIME, MON_1 + cnt),
				     month_name[cnt]))
			*decided = loc;
		      break;
		    }
		  if (match_string (_NL_CURRENT (LC_TIME, ABMON_1 + cnt), rp))
		    {
		      if (*decided == not
			  && strcmp (_NL_CURRENT (LC_TIME, ABMON_1 + cnt),
				     ab_month_name[cnt]))
			*decided = loc;
		      break;
		    }
		}
#endif
	      if (match_string (month_name[cnt], rp)
		  || match_string (ab_month_name[cnt], rp))
		{
		  *decided = raw;
		  break;
		}
	    }
	  if (cnt == 12)
	    /* Does not match a month name.  */
	    return NULL;
	  tm->tm_mon = cnt;
	  want_xday = 1;
	  break;
	case 'c':
	  /* Match locale's date and time format.  */
#ifdef _NL_CURRENT
	  if (*decided != raw)
	    {
	      if (!recursive (_NL_CURRENT (LC_TIME, D_T_FMT)))
		{
		  if (*decided == loc)
		    return NULL;
		  else
		    rp = rp_backup;
		}
	      else
		{
		  if (*decided == not &&
		      strcmp (_NL_CURRENT (LC_TIME, D_T_FMT), HERE_D_T_FMT))
		    *decided = loc;
		  want_xday = 1;
		  break;
		}
	      *decided = raw;
	    }
#endif
	  if (!recursive (HERE_D_T_FMT))
	    return NULL;
	  want_xday = 1;
	  break;
	case 'C':
	  /* Match century number.  */
	match_century:
	  get_number (0, 99, 2);
	  century = val;
	  want_xday = 1;
	  break;
	case 'd':
	case 'e':
	  /* Match day of month.  */
	  get_number (1, 31, 2);
	  tm->tm_mday = val;
	  have_mday = 1;
	  want_xday = 1;
	  break;
	case 'F':
	  if (!recursive ("%Y-%m-%d"))
	    return NULL;
	  want_xday = 1;
	  break;
	case 'x':
#ifdef _NL_CURRENT
	  if (*decided != raw)
	    {
	      if (!recursive (_NL_CURRENT (LC_TIME, D_FMT)))
		{
		  if (*decided == loc)
		    return NULL;
		  else
		    rp = rp_backup;
		}
	      else
		{
		  if (*decided == not
		      && strcmp (_NL_CURRENT (LC_TIME, D_FMT), HERE_D_FMT))
		    *decided = loc;
		  want_xday = 1;
		  break;
		}
	      *decided = raw;
	    }
#endif
	  /* Fall through.  */
	case 'D':
	  /* Match standard day format.  */
	  if (!recursive (HERE_D_FMT))
	    return NULL;
	  want_xday = 1;
	  break;
	case 'k':
	case 'H':
	  /* Match hour in 24-hour clock.  */
	  get_number (0, 23, 2);
	  tm->tm_hour = val;
	  have_I = 0;
	  break;
	case 'l':
	  /* Match hour in 12-hour clock.  GNU extension.  */
	case 'I':
	  /* Match hour in 12-hour clock.  */
	  get_number (1, 12, 2);
	  tm->tm_hour = val % 12;
	  have_I = 1;
	  break;
	case 'j':
	  /* Match day number of year.  */
	  get_number (1, 366, 3);
	  tm->tm_yday = val - 1;
	  have_yday = 1;
	  break;
	case 'm':
	  /* Match number of month.  */
	  get_number (1, 12, 2);
	  tm->tm_mon = val - 1;
	  have_mon = 1;
	  want_xday = 1;
	  break;
	case 'M':
	  /* Match minute.  */
	  get_number (0, 59, 2);
	  tm->tm_min = val;
	  break;
	case 'n':
	case 't':
	  /* Match any white space.  */
	  while (isspace (*rp))
	    ++rp;
	  break;
	case 'p':
	  /* Match locale's equivalent of AM/PM.  */
#ifdef _NL_CURRENT
	  if (*decided != raw)
	    {
	      if (match_string (_NL_CURRENT (LC_TIME, AM_STR), rp))
		{
		  if (strcmp (_NL_CURRENT (LC_TIME, AM_STR), HERE_AM_STR))
		    *decided = loc;
		  break;
		}
	      if (match_string (_NL_CURRENT (LC_TIME, PM_STR), rp))
		{
		  if (strcmp (_NL_CURRENT (LC_TIME, PM_STR), HERE_PM_STR))
		    *decided = loc;
		  is_pm = 1;
		  break;
		}
	      *decided = raw;
	    }
#endif
	  if (!match_string (HERE_AM_STR, rp))
	    if (match_string (HERE_PM_STR, rp))
	      is_pm = 1;
	    else
	      return NULL;
	  break;
	case 'r':
#ifdef _NL_CURRENT
	  if (*decided != raw)
	    {
	      if (!recursive (_NL_CURRENT (LC_TIME, T_FMT_AMPM)))
		{
		  if (*decided == loc)
		    return NULL;
		  else
		    rp = rp_backup;
		}
	      else
		{
		  if (*decided == not &&
		      strcmp (_NL_CURRENT (LC_TIME, T_FMT_AMPM),
			      HERE_T_FMT_AMPM))
		    *decided = loc;
		  break;
		}
	      *decided = raw;
	    }
#endif
	  if (!recursive (HERE_T_FMT_AMPM))
	    return NULL;
	  break;
	case 'R':
	  if (!recursive ("%H:%M"))
	    return NULL;
	  break;
	case 's':
	  {
	    /* The number of seconds may be very high so we cannot use
	       the `get_number' macro.  Instead read the number
	       character for character and construct the result while
	       doing this.  */
	    time_t secs = 0;
	    if (*rp < '0' || *rp > '9')
	      /* We need at least one digit.  */
	      return NULL;

	    do
	      {
		secs *= 10;
		secs += *rp++ - '0';
	      }
	    while (*rp >= '0' && *rp <= '9');

	    if (localtime_r (&secs, tm) == NULL)
	      /* Error in function.  */
	      return NULL;
	  }
	  break;
	case 'S':
	  get_number (0, 61, 2);
	  tm->tm_sec = val;
	  break;
	case 'X':
#ifdef _NL_CURRENT
	  if (*decided != raw)
	    {
	      if (!recursive (_NL_CURRENT (LC_TIME, T_FMT)))
		{
		  if (*decided == loc)
		    return NULL;
		  else
		    rp = rp_backup;
		}
	      else
		{
		  if (strcmp (_NL_CURRENT (LC_TIME, T_FMT), HERE_T_FMT))
		    *decided = loc;
		  break;
		}
	      *decided = raw;
	    }
#endif
	  /* Fall through.  */
	case 'T':
	  if (!recursive (HERE_T_FMT))
	    return NULL;
	  break;
	case 'u':
	  get_number (1, 7, 1);
	  tm->tm_wday = val % 7;
	  have_wday = 1;
	  break;
	case 'g':
	  get_number (0, 99, 2);
	  /* XXX This cannot determine any field in TM.  */
	  break;
	case 'G':
	  if (*rp < '0' || *rp > '9')
	    return NULL;
	  /* XXX Ignore the number since we would need some more
	     information to compute a real date.  */
	  do
	    ++rp;
	  while (*rp >= '0' && *rp <= '9');
	  break;
	case 'U':
	  get_number (0, 53, 2);
	  week_no = val;
	  have_uweek = 1;
	  break;
	case 'W':
	  get_number (0, 53, 2);
	  week_no = val;
	  have_wweek = 1;
	  break;
	case 'V':
	  get_number (0, 53, 2);
	  /* XXX This cannot determine any field in TM without some
	     information.  */
	  break;
	case 'w':
	  /* Match number of weekday.  */
	  get_number (0, 6, 1);
	  tm->tm_wday = val;
	  have_wday = 1;
	  break;
	case 'y':
	match_year_in_century:
	  /* Match year within century.  */
	  get_number (0, 99, 2);
	  /* The "Year 2000: The Millennium Rollover" paper suggests that
	     values in the range 69-99 refer to the twentieth century.  */
	  tm->tm_year = val >= 69 ? val : val + 100;
	  /* Indicate that we want to use the century, if specified.  */
	  want_century = 1;
	  want_xday = 1;
	  break;
	case 'Y':
	  /* Match year including century number.  */
	  get_number (0, 9999, 4);
	  tm->tm_year = val - 1900;
	  want_century = 0;
	  want_xday = 1;
	  break;
	case 'Z':
	  /* XXX How to handle this?  */
	  break;
	case 'E':
#ifdef _NL_CURRENT
	  switch (*fmt++)
	    {
	    case 'c':
	      /* Match locale's alternate date and time format.  */
	      if (*decided != raw)
		{
		  const char *fmt = _NL_CURRENT (LC_TIME, ERA_D_T_FMT);

		  if (*fmt == '\0')
		    fmt = _NL_CURRENT (LC_TIME, D_T_FMT);

		  if (!recursive (fmt))
		    {
		      if (*decided == loc)
			return NULL;
		      else
			rp = rp_backup;
		    }
		  else
		    {
		      if (strcmp (fmt, HERE_D_T_FMT))
			*decided = loc;
		      want_xday = 1;
		      break;
		    }
		  *decided = raw;
		}
	      /* The C locale has no era information, so use the
		 normal representation.  */
	      if (!recursive (HERE_D_T_FMT))
		return NULL;
	      want_xday = 1;
	      break;
	    case 'C':
	      if (*decided != raw)
		{
		  if (era_cnt >= 0)
		    {
		      era = _nl_select_era_entry (era_cnt HELPER_LOCALE_ARG);
		      if (era != NULL && match_string (era->era_name, rp))
			{
			  *decided = loc;
			  break;
			}
		      else
			return NULL;
		    }
		  else
		    {
		      num_eras = _NL_CURRENT_WORD (LC_TIME,
						   _NL_TIME_ERA_NUM_ENTRIES);
		      for (era_cnt = 0; era_cnt < (int) num_eras;
			   ++era_cnt, rp = rp_backup)
			{
			  era = _nl_select_era_entry (era_cnt
						      HELPER_LOCALE_ARG);
			  if (era != NULL && match_string (era->era_name, rp))
			    {
			      *decided = loc;
			      break;
			    }
			}
		      if (era_cnt == (int) num_eras)
			{
			  era_cnt = -1;
			  if (*decided == loc)
			    return NULL;
			}
		      else
			break;
		    }

		  *decided = raw;
		}
	      /* The C locale has no era information, so use the
		 normal representation.  */
	      goto match_century;
 	    case 'y':
	      if (*decided == raw)
		goto match_year_in_century;

	      get_number(0, 9999, 4);
	      tm->tm_year = val;
	      want_era = 1;
	      want_xday = 1;
	      want_century = 1;
	      break;
	    case 'Y':
	      if (*decided != raw)
		{
		  num_eras = _NL_CURRENT_WORD (LC_TIME,
					       _NL_TIME_ERA_NUM_ENTRIES);
		  for (era_cnt = 0; era_cnt < (int) num_eras;
		       ++era_cnt, rp = rp_backup)
		    {
		      era = _nl_select_era_entry (era_cnt HELPER_LOCALE_ARG);
		      if (era != NULL && recursive (era->era_format))
			break;
		    }
		  if (era_cnt == (int) num_eras)
		    {
		      era_cnt = -1;
		      if (*decided == loc)
			return NULL;
		      else
			rp = rp_backup;
		    }
		  else
		    {
		      *decided = loc;
		      era_cnt = -1;
		      break;
		    }

		  *decided = raw;
		}
	      get_number (0, 9999, 4);
	      tm->tm_year = val - 1900;
	      want_century = 0;
	      want_xday = 1;
	      break;
	    case 'x':
	      if (*decided != raw)
		{
		  const char *fmt = _NL_CURRENT (LC_TIME, ERA_D_FMT);

		  if (*fmt == '\0')
		    fmt = _NL_CURRENT (LC_TIME, D_FMT);

		  if (!recursive (fmt))
		    {
		      if (*decided == loc)
			return NULL;
		      else
			rp = rp_backup;
		    }
		  else
		    {
		      if (strcmp (fmt, HERE_D_FMT))
			*decided = loc;
		      break;
		    }
		  *decided = raw;
		}
	      if (!recursive (HERE_D_FMT))
		return NULL;
	      break;
	    case 'X':
	      if (*decided != raw)
		{
		  const char *fmt = _NL_CURRENT (LC_TIME, ERA_T_FMT);

		  if (*fmt == '\0')
		    fmt = _NL_CURRENT (LC_TIME, T_FMT);

		  if (!recursive (fmt))
		    {
		      if (*decided == loc)
			return NULL;
		      else
			rp = rp_backup;
		    }
		  else
		    {
		      if (strcmp (fmt, HERE_T_FMT))
			*decided = loc;
		      break;
		    }
		  *decided = raw;
		}
	      if (!recursive (HERE_T_FMT))
		return NULL;
	      break;
	    default:
	      return NULL;
	    }
	  break;
#else
	  /* We have no information about the era format.  Just use
	     the normal format.  */
	  if (*fmt != 'c' && *fmt != 'C' && *fmt != 'y' && *fmt != 'Y'
	      && *fmt != 'x' && *fmt != 'X')
	    /* This is an illegal format.  */
	    return NULL;

	  goto start_over;
#endif
	case 'O':
	  switch (*fmt++)
	    {
	    case 'd':
	    case 'e':
	      /* Match day of month using alternate numeric symbols.  */
	      get_alt_number (1, 31, 2);
	      tm->tm_mday = val;
	      have_mday = 1;
	      want_xday = 1;
	      break;
	    case 'H':
	      /* Match hour in 24-hour clock using alternate numeric
		 symbols.  */
	      get_alt_number (0, 23, 2);
	      tm->tm_hour = val;
	      have_I = 0;
	      break;
	    case 'I':
	      /* Match hour in 12-hour clock using alternate numeric
		 symbols.  */
	      get_alt_number (1, 12, 2);
	      tm->tm_hour = val % 12;
	      have_I = 1;
	      break;
	    case 'm':
	      /* Match month using alternate numeric symbols.  */
	      get_alt_number (1, 12, 2);
	      tm->tm_mon = val - 1;
	      have_mon = 1;
	      want_xday = 1;
	      break;
	    case 'M':
	      /* Match minutes using alternate numeric symbols.  */
	      get_alt_number (0, 59, 2);
	      tm->tm_min = val;
	      break;
	    case 'S':
	      /* Match seconds using alternate numeric symbols.  */
	      get_alt_number (0, 61, 2);
	      tm->tm_sec = val;
	      break;
	    case 'U':
	      get_alt_number (0, 53, 2);
	      week_no = val;
	      have_uweek = 1;
	      break;
	    case 'W':
	      get_alt_number (0, 53, 2);
	      week_no = val;
	      have_wweek = 1;
	      break;
	    case 'V':
	      get_alt_number (0, 53, 2);
	      /* XXX This cannot determine any field in TM without
		 further information.  */
	      break;
	    case 'w':
	      /* Match number of weekday using alternate numeric symbols.  */
	      get_alt_number (0, 6, 1);
	      tm->tm_wday = val;
	      have_wday = 1;
	      break;
	    case 'y':
	      /* Match year within century using alternate numeric symbols.  */
	      get_alt_number (0, 99, 2);
	      tm->tm_year = val >= 69 ? val : val + 100;
	      want_xday = 1;
	      break;
	    default:
	      return NULL;
	    }
	  break;
	default:
	  return NULL;
	}
    }

  if (have_I && is_pm)
    tm->tm_hour += 12;

  if (century != -1)
    {
      if (want_century)
	tm->tm_year = tm->tm_year % 100 + (century - 19) * 100;
      else
	/* Only the century, but not the year.  Strange, but so be it.  */
	tm->tm_year = (century - 19) * 100;
    }

  if (era_cnt != -1)
    {
      era = _nl_select_era_entry (era_cnt HELPER_LOCALE_ARG);
      if (era == NULL)
	return NULL;
      if (want_era)
	tm->tm_year = (era->start_date[0]
		       + ((tm->tm_year - era->offset)
			  * era->absolute_direction));
      else
	/* Era start year assumed.  */
	tm->tm_year = era->start_date[0];
    }
  else
    if (want_era)
      {
	/* No era found but we have seen an E modifier.  Rectify some
	   values.  */
	if (want_century && century == -1 && tm->tm_year < 69)
	  tm->tm_year += 100;
      }

  if (want_xday && !have_wday)
    {
      if ( !(have_mon && have_mday) && have_yday)
	{
	  /* We don't have tm_mon and/or tm_mday, compute them.  */
	  int t_mon = 0;
	  while (__mon_yday[__isleap(1900 + tm->tm_year)][t_mon] <= tm->tm_yday)
	      t_mon++;
	  if (!have_mon)
	      tm->tm_mon = t_mon - 1;
	  if (!have_mday)
	      tm->tm_mday =
		(tm->tm_yday
		 - __mon_yday[__isleap(1900 + tm->tm_year)][t_mon - 1] + 1);
	}
      day_of_the_week (tm);
    }

  if (want_xday && !have_yday)
    day_of_the_year (tm);

  if ((have_uweek || have_wweek) && have_wday)
    {
      int save_wday = tm->tm_wday;
      int save_mday = tm->tm_mday;
      int save_mon = tm->tm_mon;
      int w_offset = have_uweek ? 0 : 1;

      tm->tm_mday = 1;
      tm->tm_mon = 0;
      day_of_the_week (tm);
      if (have_mday)
	tm->tm_mday = save_mday;
      if (have_mon)
	tm->tm_mon = save_mon;

      if (!have_yday)
	tm->tm_yday = ((7 - (tm->tm_wday - w_offset)) % 7
		       + (week_no - 1) *7
		       + save_wday - w_offset);

      if (!have_mday || !have_mon)
	{
	  int t_mon = 0;
	  while (__mon_yday[__isleap(1900 + tm->tm_year)][t_mon]
		 <= tm->tm_yday)
	    t_mon++;
	  if (!have_mon)
	    tm->tm_mon = t_mon - 1;
	  if (!have_mday)
	      tm->tm_mday =
		(tm->tm_yday
		 - __mon_yday[__isleap(1900 + tm->tm_year)][t_mon - 1] + 1);
	}

      tm->tm_wday = save_wday;
    }

  return (char *) rp;
}


char *
strptime (buf, format, tm LOCALE_PARAM)
     const char *buf;
     const char *format;
     struct tm *tm;
     LOCALE_PARAM_DECL
{
  enum locale_status decided;

#ifdef _NL_CURRENT
  decided = not;
#else
  decided = raw;
#endif
  return strptime_internal (buf, format, tm, &decided, -1 LOCALE_ARG);
}
#if defined _LIBC && !defined USE_IN_EXTENDED_LOCALE_MODEL
libc_hidden_def (strptime)
#endif