(__mktime_internal): Handle broken down times around the time of the
authordrepper <drepper>
Tue, 3 Nov 1998 15:49:27 +0000 (15:49 +0000)
committerdrepper <drepper>
Tue, 3 Nov 1998 15:49:27 +0000 (15:49 +0000)
DST switches more correctly.

time/mktime.c

index 0fa92e0..6135d70 100644 (file)
@@ -350,29 +350,44 @@ __mktime_internal (tp, convert, offset)
 
   /* If we have a match, check whether tm.tm_isdst has the requested
      value, if any.  */
-  if (dt == 0 && 0 <= isdst && 0 <= tm.tm_isdst)
+  if (dt == 0 && isdst >= 0 && isdst != tm.tm_isdst)
     {
       int dst_diff = (isdst != 0) - (tm.tm_isdst != 0);
       if (dst_diff)
        {
-         /* Move two hours in the direction indicated by the disagreement,
+         /* Move three hours in the direction indicated by the disagreement,
             probe some more, and switch to a new time if found.
             The largest known fallback due to daylight savings is two hours:
-            once, in Newfoundland, 1988-10-30 02:00 -> 00:00.  */
-         time_t ot = t - 2 * 60 * 60 * dst_diff;
+            once, in Newfoundland, 1988-10-30 02:00 -> 00:00.
+            But some programs (e.g. testsuites) probe for larger differences
+            between DST and normal time so switch by three hours.  No
+            normal program does this so we do not account for more than
+            three hours difference.  */
+         time_t ot = t - 3 * 60 * 60 * dst_diff;
+         struct tm otm;
+         struct tm tmptm;
+
+         otm.tm_isdst = -1;
+
          while (--remaining_probes != 0)
            {
-             struct tm otm;
              if (! (dt = ydhms_tm_diff (year, yday, hour, min, sec,
-                                        ranged_convert (convert, &ot, &otm))))
-               {
-                 t = ot;
-                 tm = otm;
-                 break;
-               }
-             if ((ot += dt) == t)
+                                        ranged_convert (convert, &ot,
+                                                        &tmptm)))
+                 || tmptm.tm_isdst != isdst)
+               break;
+
+             otm = tmptm;
+             ot += dt;
+             if (ot == t)
                break;  /* Avoid a redundant probe.  */
            }
+
+         if (otm.tm_isdst != -1)
+           {
+             t = ot;
+             tm = otm;
+           }
        }
     }