/* Convert a string representation of time to a time value.
   Copyright (C) 1996, 1997, 1998, 1999, 2000 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 Library General Public License as
   published by the Free Software Foundation; either version 2 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
   Library General Public License for more details.

   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., 51 Franklin
   Street, Fifth Floor, Boston, MA 02110-1301, 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
#if !HAVE_STRPTIME
#include <ctype.h>
#include <limits.h>
#include <string.h>
#include <time.h>

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

#include "strptime.h"


#ifdef OS_WIN32
/* The localtime_r() definition in pthreads-win32's pthread.h doesn't guard
 * against localtime() returning NULL.
 */
#undef localtime_r
/* The localtime() in Microsoft's C library is MT-safe */
#define localtime_r(tp,tmp) (localtime(tp)?(*(tmp)=*localtime(tp),(tmp)):0)

#include <windows.h>
#include <stdlib.h>
#include <malloc.h>

#ifdef _MSC_VER
/* In MSVC, the strncasecmp function is available as _strnicmp */
# define strncasecmp _strnicmp
#endif /* _MSC_VER */

char *
get_win32_locale_string (int lctype)
{
    int nbytes = GetLocaleInfo (GetThreadLocale (), lctype, NULL, 0);
    char *tem;

    if (nbytes == 0)
        return "???";

    tem = malloc (nbytes);

    if (GetLocaleInfo (GetThreadLocale (), lctype, tem, nbytes) == 0)
    {
        free (tem);
        tem = malloc (4);
        strcpy (tem, "???");
    }

    return tem;
}

static void
append_char (char **str, int *size, int *i, char c)
{
    if (*size <= *i + 1)
    {
        char *new;
        *size *= 2;
        new = malloc (*size);
        strncpy (new, *str, *i);
        free (*str);
        *str = new;
    }
    (*str)[*i] = c;
    (*str)[++(*i)] = '\0';
}

char *
translate_win32_picture (const char *picture)
{
    int size = strlen (picture) * 2;
    char *str = malloc (size);
    int i = 0;

    str[0] = '\0';

    while (*picture)
    {
        const char *q = picture + 1;
        int count;

        while (*picture == *q)
            q++;
        count = q - picture;

        switch (*picture)
        {
        case '\'':
            picture++;
            while (*picture && *picture != '\'')
            {
                append_char (&str, &size, &i, *picture);
                picture++;
            }
            break;
        case 'd':
            switch (count)
            {
            case 1:
            case 2:
                append_char (&str, &size, &i, '%');
                append_char (&str, &size, &i, 'd');
                break;
            case 3:
            case 4:
                append_char (&str, &size, &i, '%');
                append_char (&str, &size, &i, 'a');
                break;
            }
            picture += count - 1;
            break;
        case 'M':
            switch (count)
            {
            case 1:
            case 2:
                append_char (&str, &size, &i, '%');
                append_char (&str, &size, &i, 'm');
                break;
            case 3:
            case 4:
                append_char (&str, &size, &i, '%');
                append_char (&str, &size, &i, 'b');
                break;
            }
            picture += count - 1;
            break;
        case 'y':
            switch (count)
            {
            case 1: /* Last digit of year. Ugh... */
            case 2:
                append_char (&str, &size, &i, '%');
                append_char (&str, &size, &i, 'y');
                break;
            case 4:
                append_char (&str, &size, &i, '%');
                append_char (&str, &size, &i, 'Y');
                break;
            }
            picture += count - 1;
            break;
        case 'g':
            /* Era. Huh. Just ignore, as the era stuff
             * implementation below depends on glibc.
             */
            picture += count - 1;
            break;
        case 'h':
            append_char (&str, &size, &i, '%');
            append_char (&str, &size, &i, 'I');
            picture += count - 1;
            break;
        case 'H':
            append_char (&str, &size, &i, '%');
            append_char (&str, &size, &i, 'H');
            picture += count - 1;
            break;
        case 'm':
            append_char (&str, &size, &i, '%');
            append_char (&str, &size, &i, 'M');
            picture += count - 1;
            break;
        case 's':
            append_char (&str, &size, &i, '%');
            append_char (&str, &size, &i, 'S');
            picture += count - 1;
            break;
        case 't':
            append_char (&str, &size, &i, '%');
            append_char (&str, &size, &i, 'p');
            picture += count - 1;
            break;
        default:
            append_char (&str, &size, &i, *picture);
            break;
        }
        if (*picture)
            picture++;
    }

    return str;
}

#endif /* OS_WIN32 */


#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
#  include "localtime_r.h"
# 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)						      \
      {									      \
	const char *alts = _NL_CURRENT (LC_TIME, ALT_DIGITS);		      \
	int __n = n;							      \
	int any = 0;							      \
	while (*rp == ' ')						      \
	  ++rp;								      \
	val = 0;							      \
	do {								      \
	  val *= 10;							      \
	  while (*alts != '\0')						      \
	    {								      \
	      size_t len = strlen (alts);				      \
	      if (strncasecmp (alts, rp, len) == 0)			      \
	        break;							      \
	      alts += len + 1;						      \
	      ++val;							      \
	    }								      \
	  if (*alts == '\0')						      \
	    {								      \
	      if (*decided == not && ! any)				      \
		goto do_normal;						      \
	      /* If we haven't read anything it's an error.  */		      \
	      if (! any)						      \
		return NULL;						      \
	      /* Correct the premature multiplication.  */		      \
	      val /= 10;						      \
	      break;							      \
	    }								      \
	  else								      \
	    *decided = loc;						      \
	} while (--__n > 0 && val * 10 <= to);				      \
	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 _LIBC
/* 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
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

/* 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));

static char *
#ifdef _LIBC
internal_function
#endif
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;
#ifdef _NL_CURRENT
    size_t num_eras;
    struct era_entry *era;
    era = NULL;
#endif
    have_I = is_pm = 0;
    century = -1;
    want_century = 0;
    want_era = 0;

    have_wday = want_xday = have_yday = have_mon = have_mday = 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 input 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;
                    }
                }
#elif defined (OS_WIN32)
                if (*decided != raw)
                {
                    char *locale_string = get_win32_locale_string (LOCALE_SDAYNAME1 + cnt);
                    if (match_string (locale_string, rp))
                    {
                        if (*decided == not
                                && strcmp (locale_string, weekday_name[cnt]))
                            *decided = loc;
                        free (locale_string);
                        break;
                    }
                    free (locale_string);
                    locale_string = get_win32_locale_string (LOCALE_SABBREVDAYNAME1 + cnt);
                    if (match_string (locale_string, rp))
                    {
                        if (*decided == not
                                && strcmp (locale_string, ab_weekday_name[cnt]))
                            *decided = loc;
                        free (locale_string);
                        break;
                    }
                    free (locale_string);
                }
#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;
                    }
                }
#elif defined (OS_WIN32)
                if (*decided != raw)
                {
                    char *locale_string = get_win32_locale_string (LOCALE_SMONTHNAME1 + cnt);
                    if (match_string (locale_string, rp))
                    {
                        if (*decided == not
                                && strcmp (locale_string, month_name[cnt]))
                            *decided = loc;
                        free (locale_string);
                        break;
                    }
                    free (locale_string);
                    locale_string = get_win32_locale_string (LOCALE_SABBREVMONTHNAME1 + cnt);
                    if (match_string (locale_string, rp))
                    {
                        if (*decided == not
                                && strcmp (locale_string, ab_month_name[cnt]))
                            *decided = loc;
                        free (locale_string);
                        break;
                    }
                    free (locale_string);
                }
#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;
            }
#elif defined (OS_WIN32)
            if (*decided != raw)
            {
                char *date_locale_string = get_win32_locale_string (LOCALE_SSHORTDATE);
                char *time_locale_string = get_win32_locale_string (LOCALE_STIMEFORMAT);
                int date_len = strlen (date_locale_string);
                int time_len = strlen (time_locale_string);
                char *d_t_fmt = malloc (date_len + time_len + 2);
                char *posix_d_t_fmt;

                strncpy (d_t_fmt, date_locale_string, date_len);
                strcat (d_t_fmt, " ");
                strncat (d_t_fmt, time_locale_string, time_len);
                free (date_locale_string);
                free (time_locale_string);

                posix_d_t_fmt = translate_win32_picture (d_t_fmt);

                free (d_t_fmt);

                if (!recursive (posix_d_t_fmt))
                {
                    if (*decided == loc)
                    {
                        free (posix_d_t_fmt);
                        return NULL;
                    }
                    else
                    {
                        rp = rp_backup;
                    }
                }
                else
                {
                    if (*decided == not &&
                            strcmp (posix_d_t_fmt, HERE_D_T_FMT))
                        *decided = loc;
                    want_xday = 1;
                    free (posix_d_t_fmt);
                    break;
                }
                free (posix_d_t_fmt);
                *decided = raw;
            }
#endif
            if (!recursive (HERE_D_T_FMT))
                return NULL;
            want_xday = 1;
            break;
        case 'C':
            /* Match century number.  */
#ifdef _NL_CURRENT
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 _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;
            }
#elif defined (OS_WIN32)
            if (*decided != raw)
            {
                char *locale_string = get_win32_locale_string (LOCALE_SSHORTDATE);
                char *posix_d_fmt = translate_win32_picture (locale_string);

                free (locale_string);

                if (!recursive (posix_d_fmt))
                {
                    if (*decided == loc)
                    {
                        free(posix_d_fmt);
                        return NULL;
                    }
                    else
                    {
                        rp = rp_backup;
                    }
                }
                else
                {
                    if (*decided == not
                            && strcmp (posix_d_fmt, HERE_D_FMT))
                        *decided = loc;
                    want_xday = 1;
                    free(posix_d_fmt);
                    break;
                }
                free(posix_d_fmt);
                *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 '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;
            }
#elif defined (OS_WIN32)
            if (*decided != raw)
            {
                char *locale_string = get_win32_locale_string (LOCALE_S1159);
                if (match_string (locale_string, rp))
                {
                    if (strcmp (locale_string, HERE_AM_STR))
                        *decided = loc;
                    free (locale_string);
                    break;
                }
                free (locale_string);
                locale_string = get_win32_locale_string (LOCALE_S2359);
                if (match_string (locale_string, rp))
                {
                    if (strcmp (locale_string, HERE_PM_STR))
                        *decided = loc;
                    is_pm = 1;
                    free (locale_string);
                    break;
                }
                *decided = raw;
                free (locale_string);
            }
#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;
            }
#elif defined (OS_WIN32)
            if (*decided != raw)
            {
                char *locale_string = get_win32_locale_string (LOCALE_STIMEFORMAT);
                int locale_len = strlen (locale_string);
                char *t_p_fmt = malloc (locale_len + 4);
                char *posix_t_p_fmt;

                strncpy (t_p_fmt, locale_string, locale_len);
                strcat (t_p_fmt, " tt");

                posix_t_p_fmt = translate_win32_picture (t_p_fmt);

                free (t_p_fmt);

                if (!recursive (posix_t_p_fmt))
                {
                    if (*decided == loc)
                    {
                        free (posix_t_p_fmt);
                        return NULL;
                    }
                    else
                    {
                        rp = rp_backup;
                    }
                }
                else
                {
                    if (*decided == not &&
                            strcmp (posix_t_p_fmt,
                                    HERE_T_FMT_AMPM))
                        *decided = loc;
                    free (posix_t_p_fmt);
                    break;
                }
                free (posix_t_p_fmt);
                *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;
            }
#elif defined (OS_WIN32)
            if (*decided != raw)
            {
                char *locale_string = get_win32_locale_string (LOCALE_STIMEFORMAT);
                char *posix_t_fmt = translate_win32_picture (locale_string);

                free (locale_string);

                if (!recursive (posix_t_fmt))
                {
                    if (*decided == loc)
                    {
                        free (posix_t_fmt);
                        return NULL;
                    }
                    else
                    {
                        rp = rp_backup;
                    }
                }
                else
                {
                    if (strcmp (posix_t_fmt, HERE_T_FMT))
                        *decided = loc;
                    free (posix_t_fmt);
                    break;
                }
                free (posix_t_fmt);
                *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':
        case 'V':
        case 'W':
            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 _NL_CURRENT
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 _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);
                        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;
                }
                /* 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;
                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);
                        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;
                }
                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 - 1;
                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':
            case 'V':
            case 'W':
                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 _NL_CURRENT
    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)
            return NULL;

    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);

    return (char *) rp;
}


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

#ifdef _NL_CURRENT
    decided = not;
#elif defined (OS_WIN32)
    decided = not;
#else
    decided = raw;
#endif
    return strptime_internal (buf, format, tm, &decided, -1);
}

#endif /* !HAVE_STRPTIME */