[src/trunk]: src/lib/libc/time prevent underflow from giving us a false posit...

[christos <christos%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/4af0a81d5706
branches:  trunk
changeset: 770664:4af0a81d5706
user:      christos <christos%NetBSD.org@localhost>
date:      Fri Oct 28 13:53:06 2011 +0000

description:
prevent underflow from giving us a false positive test in the first iteration.

diffstat:

 lib/libc/time/localtime.c |  12 +++++++++---
 1 files changed, 9 insertions(+), 3 deletions(-)

diffs (47 lines):

diff -r 0e589c3ab805 -r 4af0a81d5706 lib/libc/time/localtime.c
--- a/lib/libc/time/localtime.c Fri Oct 28 13:18:57 2011 +0000
+++ b/lib/libc/time/localtime.c Fri Oct 28 13:53:06 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: localtime.c,v 1.60 2011/10/27 14:48:00 christos Exp $  */
+/*     $NetBSD: localtime.c,v 1.61 2011/10/28 13:53:06 christos Exp $  */
 
 /*
 ** This file is in the public domain, so clarified as of
@@ -10,7 +10,7 @@
 #if 0
 static char    elsieid[] = "@(#)localtime.c    8.17";
 #else
-__RCSID("$NetBSD: localtime.c,v 1.60 2011/10/27 14:48:00 christos Exp $");
+__RCSID("$NetBSD: localtime.c,v 1.61 2011/10/28 13:53:06 christos Exp $");
 #endif
 #endif /* LIBC_SCCS and not lint */
 
@@ -1792,6 +1792,9 @@
        long                    li;
        time_t                  lo;
        time_t                  hi;
+#ifdef NO_ERROR_IN_DST_GAP
+       time_t                  ilo;
+#endif
        long                            y;
        time_t                          newt;
        time_t                          t;
@@ -1886,6 +1889,9 @@
                        lo *= 2;
                hi = -(lo + 1);
        }
+#ifdef NO_ERROR_IN_DST_GAP
+       ilo = lo;
+#endif
        for ( ; ; ) {
                t = lo / 2 + hi / 2;
                if (t < lo)
@@ -1913,7 +1919,7 @@
                                --hi;
                        }
 #ifdef NO_ERROR_IN_DST_GAP
-                       if (lo - 1 == hi && yourtm.tm_isdst < 0) {
+                       if (ilo != lo && lo - 1 == hi && yourtm.tm_isdst < 0) {
                                time_t off = 0;
                                for (i = sp->typecnt - 1; i >= 0; --i) {
                                        for (j = sp->typecnt - 1; j >= 0; --j) {