X-Git-Url: https://code.delx.au/gnu-emacs/blobdiff_plain/68c45bf06516ed4650eb7f9f617742d84750600a..974aae61bbb8c05e0d0fc1a95b419fe596423fd8:/src/mktime.c

diff --git a/src/mktime.c b/src/mktime.c
index 3b3330eea0..c61f146356 100644
--- a/src/mktime.c
+++ b/src/mktime.c
@@ -17,7 +17,7 @@
 
    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
-   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
+   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
    USA.  */
 
 /* Define this to have a standalone program to test this implementation of
@@ -117,7 +117,9 @@ const unsigned short int __mon_yday[2][13] =
    localtime to localtime_r, since many localtime_r implementations
    are buggy.  */
 static struct tm *
-my_mktime_localtime_r (const time_t *t, struct tm *tp)
+my_mktime_localtime_r (t, tp)
+     const time_t *t;
+     struct tm *tp;
 {
   struct tm *l = localtime (t);
   if (! l)
@@ -135,8 +137,9 @@ my_mktime_localtime_r (const time_t *t, struct tm *tp)
    If TP is null, return a nonzero value.
    If overflow occurs, yield the low order bits of the correct answer.  */
 static time_t
-ydhms_tm_diff (int year, int yday, int hour, int min, int sec,
-	       const struct tm *tp)
+ydhms_tm_diff (year, yday, hour, min, sec, tp)
+     int year, yday, hour, min, sec;
+     const struct tm *tp;
 {
   if (!tp)
     return 1;
@@ -167,8 +170,14 @@ ydhms_tm_diff (int year, int yday, int hour, int min, int sec,
    If *T is out of range for conversion, adjust it so that
    it is the nearest in-range value and then convert that.  */
 static struct tm *
-ranged_convert (struct tm *(*convert) (const time_t *, struct tm *),
-		time_t *t, struct tm *tp)
+ranged_convert (convert, t, tp)
+#ifdef PROTOTYPES
+     struct tm *(*convert) (const time_t *, struct tm *);
+#else
+     struct tm *(*convert)();
+#endif
+     time_t *t;
+     struct tm *tp;
 {
   struct tm *r;
 
@@ -215,9 +224,14 @@ ranged_convert (struct tm *(*convert) (const time_t *, struct tm *),
    compared to what the result would be for UTC without leap seconds.
    If *OFFSET's guess is correct, only one CONVERT call is needed.  */
 time_t
-__mktime_internal (struct tm *tp,
-		   struct tm *(*convert) (const time_t *, struct tm *),
-		   time_t *offset)
+__mktime_internal (tp, convert, offset)
+     struct tm *tp;
+#ifdef PROTOTYPES
+     struct tm *(*convert) (const time_t *, struct tm *);
+#else
+     struct tm *(*convert)();
+#endif
+     time_t *offset;
 {
   time_t t, dt, t0, t1, t2;
   struct tm tm;
@@ -238,6 +252,9 @@ __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;
@@ -256,6 +273,13 @@ __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.  */
@@ -272,20 +296,24 @@ __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;
@@ -359,6 +387,14 @@ __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;
 }
@@ -528,3 +564,6 @@ Local Variables:
 compile-command: "gcc -DDEBUG -DHAVE_LIMITS_H -DSTDC_HEADERS -Wall -W -O -g mktime.c -o mktime"
 End:
 */
+
+/* arch-tag: 9456752f-7ddd-47cb-8286-fa807b1355ae
+   (do not change this comment) */