(compute_change): Replace slow loop to compute T by simple algorithm.
[kopensolaris-gnu/glibc.git] / time / strptime.c
index cb3d126..5f8271e 100644 (file)
@@ -1,22 +1,31 @@
-/* strptime - Convert a string representation of time to a time value.
-Copyright (C) 1996 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., 59 Temple Place - Suite 330,
-Boston, MA 02111-1307, USA.  */
+/* Convert a string representation of time to a time value.
+   Copyright (C) 1996, 1997, 1998, 1999 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., 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>
@@ -24,66 +33,252 @@ Boston, MA 02111-1307, USA.  */
 #include <string.h>
 #include <time.h>
 
-#include "../locale/localeinfo.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
-#define match_string(cs1, s2)                                                \
+#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;                                                  \
+     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)                                                 \
+#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 (val * 10 <= to && *rp >= '0' && *rp <= '9');                    \
+    } while (--__n > 0 && val * 10 <= to && *rp >= '0' && *rp <= '9');       \
     if (val < from || val > to)                                                      \
       return NULL;                                                           \
   } while (0)
-#define get_alt_number(from, to)                                             \
-  do {                                                                       \
-    const char *alts = _NL_CURRENT (LC_TIME, ALT_DIGITS);                    \
-    val = 0;                                                                 \
-    while (*alts != '\0')                                                    \
+#ifdef _NL_CURRENT
+# define get_alt_number(from, to, n) \
+  ({                                                                         \
+    __label__ do_normal;                                                     \
+    if (*decided != raw)                                                     \
       {                                                                              \
-       size_t len = strlen (alts);                                           \
-       if (strncasecmp (alts, rp, len) == 0)                                 \
-         break;                                                              \
-       alts = strchr (alts, '\0') + 1;                                       \
-       ++val;                                                                \
+       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;                                                        \
       }                                                                              \
-    if (*alts == '\0')                                                       \
-      return NULL;                                                           \
-  } while (0)
-#define recursive(new_fmt)                                                   \
-  do {                                                                       \
-    if (*new_fmt == '\0')                                                    \
-      return NULL;                                                           \
-    rp = strptime (rp, new_fmt, tm);                                         \
-    if (rp == NULL)                                                          \
-      return NULL;                                                           \
-  } while (0)
-  
+    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)) != NULL)
 
-char *
-strptime (const char *buf, const char *format, struct tm *tm)
+
+#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;
+}
+
+/* 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 *buf, const char *format, struct tm *tm,
+                       enum locale_status *decided));
+
+static char *
+#ifdef _LIBC
+internal_function
+#endif
+strptime_internal (buf, format, tm, decided)
+     const char *buf;
+     const char *format;
+     struct tm *tm;
+     enum locale_status *decided;
 {
   const char *rp;
   const char *fmt;
   int cnt;
   size_t val;
   int have_I, is_pm;
+  int century, want_century;
+  int have_wday, want_xday;
+  int have_yday;
+  int have_mon, have_mday;
 
   rp = buf;
   fmt = format;
   have_I = is_pm = 0;
+  century = -1;
+  want_century = 0;
+  have_wday = want_xday = have_yday = have_mon = have_mday = 0;
 
   while (*fmt != '\0')
     {
@@ -106,6 +301,10 @@ strptime (const char *buf, const char *format, struct tm *tm)
        }
 
       ++fmt;
+#ifndef _NL_CURRENT
+      /* We need this for handling the `E' modifier.  */
+    start_over:
+#endif
       switch (*fmt++)
        {
        case '%':
@@ -117,15 +316,40 @@ strptime (const char *buf, const char *format, struct tm *tm)
          /* Match day of week.  */
          for (cnt = 0; cnt < 7; ++cnt)
            {
-             if (match_string (_NL_CURRENT (LC_TIME, ABDAY_1 + cnt), rp))
-               break;
-             if (match_string (_NL_CURRENT (LC_TIME, DAY_1 + cnt), rp))
-               break;
+#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':
@@ -133,60 +357,140 @@ strptime (const char *buf, const char *format, struct tm *tm)
          /* Match month name.  */
          for (cnt = 0; cnt < 12; ++cnt)
            {
-             if (match_string (_NL_CURRENT (LC_TIME, ABMON_1 + cnt), rp))
-               break;
-             if (match_string (_NL_CURRENT (LC_TIME, MON_1 + cnt), rp))
-               break;
+#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.  */
-         recursive (_NL_CURRENT (LC_TIME, D_T_FMT));
+#ifdef _NL_CURRENT
+         if (*decided != raw)
+           {
+             if (!recursive (_NL_CURRENT (LC_TIME, D_T_FMT)))
+               {
+                 if (*decided == loc)
+                   return NULL;
+               }
+             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.  */
-         get_number (0, 99);
-         /* We don't need the number.  */
+         get_number (0, 99, 2);
+         century = val;
+         want_xday = 1;
          break;
        case 'd':
        case 'e':
          /* Match day of month.  */
-         get_number (1, 31);
+         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
+               {
+                 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.  */
-         recursive ("%m/%d/%y");
+         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);
+         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);
-         tm->tm_hour = val - 1;
+         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);
+         get_number (1, 366, 3);
          tm->tm_yday = val - 1;
+         have_yday = 1;
          break;
        case 'm':
          /* Match number of month.  */
-         get_number (1, 12);
+         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);
+         get_number (0, 59, 2);
          tm->tm_min = val;
          break;
        case 'n':
@@ -197,63 +501,191 @@ strptime (const char *buf, const char *format, struct tm *tm)
          break;
        case 'p':
          /* Match locale's equivalent of AM/PM.  */
-         if (match_string (_NL_CURRENT (LC_TIME, AM_STR), rp))
-           break;
-         if (match_string (_NL_CURRENT (LC_TIME, PM_STR), rp))
+#ifdef _NL_CURRENT
+         if (*decided != raw)
            {
-             is_pm = 1;
-             break;
+             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;
            }
-         return NULL;
+#endif
+         if (!match_string (HERE_AM_STR, rp))
+           if (match_string (HERE_PM_STR, rp))
+             is_pm = 1;
+           else
+             return NULL;
+         break;
        case 'r':
-         recursive (_NL_CURRENT (LC_TIME, T_FMT_AMPM));
+#ifdef _NL_CURRENT
+         if (*decided != raw)
+           {
+             if (!recursive (_NL_CURRENT (LC_TIME, T_FMT_AMPM)))
+               {
+                 if (*decided == loc)
+                   return NULL;
+               }
+             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':
-         recursive ("%H:%M");
+         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);
+         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
+               {
+                 if (strcmp (_NL_CURRENT (LC_TIME, T_FMT), HERE_T_FMT))
+                   *decided = loc;
+                 break;
+               }
+             *decided = raw;
+           }
+#endif
+         /* Fall through.  */
        case 'T':
-         recursive ("%H:%M:%S");
+         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);
-         /* XXX This cannot determine any field in TM.  */
+         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);
+         get_number (0, 6, 1);
          tm->tm_wday = val;
-         break;
-       case 'x':
-         recursive (_NL_CURRENT (LC_TIME, D_FMT));
-         break;
-       case 'X':
-         recursive (_NL_CURRENT (LC_TIME, T_FMT));
+         have_wday = 1;
          break;
        case 'y':
          /* Match year within century.  */
-         get_number (0, 99);
-         tm->tm_year = val;
+         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, INT_MAX);
-         tm->tm_year = val - (val >= 2000 ? 2000 : 1900);
+         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.  */
-             recursive (_NL_CURRENT (LC_TIME, ERA_D_T_FMT));
+             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
+                   {
+                     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':
            case 'y':
@@ -261,72 +693,130 @@ strptime (const char *buf, const char *format, struct tm *tm)
              /* Match name of base year in locale's alternate
                 representation.  */
              /* XXX This is currently not implemented.  It should
-                use the value _NL_CURRENT (LC_TIME, ERA) but POSIX
-                leaves this implementation defined and we haven't
-                figured out how to do it yet.  */
+                use the value _NL_CURRENT (LC_TIME, ERA).  */
              break;
            case 'x':
-             recursive (_NL_CURRENT (LC_TIME, ERA_D_FMT));
+             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
+                   {
+                     if (strcmp (fmt, HERE_D_FMT))
+                       *decided = loc;
+                     break;
+                   }
+                 *decided = raw;
+               }
+             if (!recursive (HERE_D_FMT))
+               return NULL;
              break;
            case 'X':
-             recursive (_NL_CURRENT (LC_TIME, ERA_T_FMT));
+             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
+                   {
+                     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);
+             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);
+             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);
+             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);
+             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);
+             get_alt_number (0, 59, 2);
              tm->tm_min = val;
              break;
            case 'S':
              /* Match seconds using alternate numeric symbols.  */
-             get_alt_number (0, 61);
+             get_alt_number (0, 61, 2);
              tm->tm_sec = val;
              break;
            case 'U':
            case 'V':
            case 'W':
-             get_alt_number (0, 53);
-             /* XXX This cannot determine any field in TM.  */
+             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);
+             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);
+             get_alt_number (0, 99, 2);
+             tm->tm_year = val >= 69 ? val : val + 100;
+             want_xday = 1;
              break;
            default:
              return NULL;
@@ -339,6 +829,41 @@ strptime (const char *buf, const char *format, struct tm *tm)
 
   if (have_I && is_pm)
     tm->tm_hour += 12;
-  
+
+  if (want_century && century != -1)
+    tm->tm_year = tm->tm_year % 100 + (century - 19) * 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);
+
   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;
+#else
+  decided = raw;
+#endif
+  return strptime_internal (buf, format, tm, &decided);
+}