path: root/libc/misc/time/strptime.c

/* Convert a string representation of time to a time value.
   Copyright (C) 1996-2000, 2001 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.  */

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

#undef ENABLE_ERA_JUNK


#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 __UCLIBC_HAS_LOCALE__
# define get_alt_number(from, to, n) \
  ({									      \
     __label__ do_normal;						      \
									      \
     if (*decided != raw)						      \
       {								      \
	 val = _nl_parse_alt_digit (&rp);				      \
	 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)) != NULL)


#ifdef __UCLIBC_HAS_LOCALE__
/* This is defined in locale/C-time.c in the GNU libc.  */
extern const struct locale_data _nl_C_LC_TIME;
extern const unsigned short int __mon_yday[2][13];

# 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
extern char const __weekday_name[][10];
extern char const __ab_weekday_name[][4];
extern char const __month_name[][10];
extern char const __ab_month_name[][4];
extern const unsigned short int __mon_yday[2][13];
# 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"
#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 * __strptime_internal (rp, fmt, tm, decided, era_cnt)
     const char *rp;
     const char *fmt;
     struct tm *tm;
     enum locale_status *decided;
     int era_cnt;
{
    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;
#ifdef ENABLE_ERA_JUNK
    size_t num_eras;
    struct era_entry *era;

    era = NULL;
#endif
    have_I = is_pm = 0;
    century = -1;
    want_century = 0;
    want_era = 0;
    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 __UCLIBC_HAS_LOCALE__
	/* 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 __UCLIBC_HAS_LOCALE__
		    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 __UCLIBC_HAS_LOCALE__
		    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 __UCLIBC_HAS_LOCALE__
		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.  */
#ifdef __UCLIBC_HAS_LOCALE__
match_century:
#endif
		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 __UCLIBC_HAS_LOCALE__
		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 __UCLIBC_HAS_LOCALE__
		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 __UCLIBC_HAS_LOCALE__
		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 __UCLIBC_HAS_LOCALE__
		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':
#ifdef __UCLIBC_HAS_LOCALE__
match_year_in_century:
#endif
		/* 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 __UCLIBC_HAS_LOCALE__
		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':
#ifdef ENABLE_ERA_JUNK
			if (*decided != raw)
			{
			    if (era_cnt >= 0)
			    {
				era = _nl_select_era_entry (era_cnt);
				if (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);
				    if (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;
			}
#endif
			/* 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':
#ifdef ENABLE_ERA_JUNK
			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);
				if (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;
			}
#endif
			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;
    }

#ifdef ENABLE_ERA_JUNK
    if (era_cnt != -1)
    {
	era = _nl_select_era_entry (era_cnt);
	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
#endif
	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)
     const char *buf;
     const char *format;
     struct tm *tm;
{
    enum locale_status decided;

#ifdef __UCLIBC_HAS_LOCALE__
    decided = not;
#else
    decided = raw;
#endif
    return __strptime_internal (buf, format, tm, &decided, -1);
}