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[gnulib.git] / lib / mktime.c

diff --git a/lib/mktime.c b/lib/mktime.c
index 037510d..2221790 100644 (file)
--- a/lib/mktime.c
+++ b/lib/mktime.c
@@ -52,6 +52,7 @@
 # include <stdio.h>
 # if STDC_HEADERS
 #  include <stdlib.h>
+#  include <string.h>
 # endif
 /* Make it work even if the system's libc has its own mktime routine.  */
 # define mktime my_mktime
@@ -102,7 +103,10 @@
 #endif
 
 /* How many days come before each month (0-12).  */
-STATIC const unsigned short int __mon_yday[2][13] =
+#ifndef _LIBC
+static
+#endif
+const unsigned short int __mon_yday[2][13] =
   {
     /* Normal years.  */
     { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 },
@@ -215,7 +219,10 @@ ranged_convert (struct tm *(*convert) (const time_t *, struct tm *),
    Use *OFFSET to keep track of a guess at the offset of the result,
    compared to what the result would be for UTC without leap seconds.
    If *OFFSET's guess is correct, only one CONVERT call is needed.  */
-STATIC time_t
+#ifndef _LIBC
+static
+#endif
+time_t
 __mktime_internal (struct tm *tp,
                   struct tm *(*convert) (const time_t *, struct tm *),
                   time_t *offset)
@@ -239,6 +246,9 @@ __mktime_internal (struct tm *tp,
   int year_requested = tp->tm_year;
   int isdst = tp->tm_isdst;
 
+  /* 1 if the previous probe was DST.  */
+  int dst2;
+
   /* Ensure that mon is in range, and set year accordingly.  */
   int mon_remainder = mon % 12;
   int negative_mon_remainder = mon_remainder < 0;
@@ -257,6 +267,13 @@ __mktime_internal (struct tm *tp,
              + mday - 1);
 
   int sec_requested = sec;
+
+  /* Only years after 1970 are defined.
+     If year is 69, it might still be representable due to
+     timezone differences.  */
+  if (year < 69)
+    return -1;
+
 #if LEAP_SECONDS_POSSIBLE
   /* Handle out-of-range seconds specially,
      since ydhms_tm_diff assumes every minute has 60 seconds.  */
@@ -273,20 +290,24 @@ __mktime_internal (struct tm *tp,
   tm.tm_yday = tm.tm_hour = tm.tm_min = tm.tm_sec = 0;
   t0 = ydhms_tm_diff (year, yday, hour, min, sec, &tm);
 
-  for (t = t1 = t2 = t0 + *offset;
+  for (t = t1 = t2 = t0 + *offset, dst2 = 0;
        (dt = ydhms_tm_diff (year, yday, hour, min, sec,
                            ranged_convert (convert, &t, &tm)));
-       t1 = t2, t2 = t, t += dt)
+       t1 = t2, t2 = t, t += dt, dst2 = tm.tm_isdst != 0)
     if (t == t1 && t != t2
-       && (isdst < 0 || tm.tm_isdst < 0
-           || (isdst != 0) != (tm.tm_isdst != 0)))
+       && (tm.tm_isdst < 0
+           || (isdst < 0
+               ? dst2 <= (tm.tm_isdst != 0)
+               : (isdst != 0) != (tm.tm_isdst != 0))))
       /* We can't possibly find a match, as we are oscillating
         between two values.  The requested time probably falls
         within a spring-forward gap of size DT.  Follow the common
         practice in this case, which is to return a time that is DT
         away from the requested time, preferring a time whose
-        tm_isdst differs from the requested value.  In practice,
-        this is more useful than returning -1.  */
+        tm_isdst differs from the requested value.  (If no tm_isdst
+        was requested and only one of the two values has a nonzero
+        tm_isdst, prefer that value.)  In practice, this is more
+        useful than returning -1.  */
       break;
     else if (--remaining_probes == 0)
       return -1;
@@ -360,6 +381,14 @@ __mktime_internal (struct tm *tp,
        return -1;
     }
 
+  if (year == 69)
+    {
+      /* If year was 69, need to check whether the time was representable
+        or not.  */
+      if (t < 0 || t > 2 * 24 * 60 * 60)
+       return -1;
+    }
+
   *tp = tm;
   return t;
 }
@@ -385,6 +414,11 @@ mktime (tp)
 #ifdef weak_alias
 weak_alias (mktime, timelocal)
 #endif
+
+#ifdef _LIBC
+libc_hidden_def (mktime)
+libc_hidden_weak (timelocal)
+#endif
 \f
 #if DEBUG