[src/trunk]: src/lib/libc/time Add code (not enabled) that allows mktime() to...

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

details:   https://anonhg.NetBSD.org/src/rev/193d2fbbe81e
branches:  trunk
changeset: 770431:193d2fbbe81e
user:      christos <christos%NetBSD.org@localhost>
date:      Sun Oct 16 17:59:32 2011 +0000

description:
Add code (not enabled) that allows mktime() to return a value for times
in the DST gap when tm_isdst == -1, like glibc does. Document both behaviors.

diffstat:

 lib/libc/time/Makefile    |   2 ++
 lib/libc/time/ctime.3     |  17 +++++++++++++++--
 lib/libc/time/localtime.c |  25 +++++++++++++++++++++++--
 3 files changed, 40 insertions(+), 4 deletions(-)

diffs (92 lines):

diff -r 05104b7f61fd -r 193d2fbbe81e lib/libc/time/Makefile
--- a/lib/libc/time/Makefile    Sun Oct 16 17:24:50 2011 +0000
+++ b/lib/libc/time/Makefile    Sun Oct 16 17:59:32 2011 +0000
@@ -113,6 +113,8 @@
 #  -DNO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU=1
 #      if you do not want run time warnings about formats that may cause
 #      year 2000 grief
+#  -DNO_ERROR_IN_DST_GAP=1
+#      if you want mktime() not to return an error in the DST gap.
 #  -DZIC_MAX_ABBR_LEN_WO_WARN=3
 #      (or some other number) to set the maximum time zone abbreviation length
 #      that zic will accept without a warning (the default is 6)
diff -r 05104b7f61fd -r 193d2fbbe81e lib/libc/time/ctime.3
--- a/lib/libc/time/ctime.3     Sun Oct 16 17:24:50 2011 +0000
+++ b/lib/libc/time/ctime.3     Sun Oct 16 17:59:32 2011 +0000
@@ -1,8 +1,8 @@
-.\" $NetBSD: ctime.3,v 1.42 2011/07/09 09:12:11 plunky Exp $
+.\" $NetBSD: ctime.3,v 1.43 2011/10/16 17:59:32 christos Exp $
 .\"
 .\" XXX: Lincense missing?
 .\"
-.Dd July 9, 2011
+.Dd October 16, 2011
 .Dt CTIME 3
 .Os
 .Sh NAME
@@ -245,6 +245,19 @@
 The function returns the specified calendar time;
 if the calendar time cannot be represented, it returns
 .Va "(time_t)-1" .
+This can happen either because the resulting conversion would not fit
+in a
+.Vt time_t
+variable, or because the time specified happens to be in the daylight
+savings gap and
+.Fa tm_isdst
+was set to
+.Dv \-1 .
+Other
+.Fn mktime
+implementations do not return an error in the second case and return
+the appropriate time offset after the daylight savings gap.
+There is code to mimick this behavior, but it is not enabled by default.
 .It Fn mktime_z "tz" "tm"
 The
 .Fn mktime_z
diff -r 05104b7f61fd -r 193d2fbbe81e lib/libc/time/localtime.c
--- a/lib/libc/time/localtime.c Sun Oct 16 17:24:50 2011 +0000
+++ b/lib/libc/time/localtime.c Sun Oct 16 17:59:32 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: localtime.c,v 1.58 2011/09/04 10:10:26 christos Exp $  */
+/*     $NetBSD: localtime.c,v 1.59 2011/10/16 17:59:32 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 1.58 2011/09/04 10:10:26 christos Exp $");
+__RCSID("$NetBSD: localtime.c,v 1.59 2011/10/16 17:59:32 christos Exp $");
 #endif
 #endif /* LIBC_SCCS and not lint */
 
@@ -1912,6 +1912,27 @@
                                        return WRONG;
                                --hi;
                        }
+#ifdef NO_ERROR_IN_DST_GAP
+                       if (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) {
+                                               if (sp->ttis[j].tt_isdst ==
+                                                   sp->ttis[i].tt_isdst)
+                                                       continue;
+                                               off = sp->ttis[j].tt_gmtoff -
+                                                   sp->ttis[i].tt_gmtoff;
+                                               break;
+                                       }
+                                       if (j >= 0)
+                                               break;
+                               }
+                               if (off) {
+                                       t = hi + off;
+                                       break;
+                               }
+                       }
+#endif
                        if (lo > hi)
                                return WRONG;
                        if (dir > 0)