fix [clock format -timezone :localtime] for times before the Posix Epoch

2 files changed, 15 insertions, 8 deletions

diff --git a/ChangeLog b/ChangeLog
index 9cd8c74..d0b971d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -20,10 +20,12 @@
 
 2005-11-30  Kevin Kenny  <kennykb@acm.org>
 
-	* generic/tclClock.c: Fixed a bad refcount in previous commit that led
-	to a corrupted heap. Thanks to Miguel Sofer for pointing out this
-	bug.  Also silenced a warning that some compilers gave about the
-	excessively long constant for JULIAN_SEC_POSIX_EPOCH.
+	* generic/tclClock.c: Fixed a bad refcount in previous commit that
+	led to a corrupted heap. Also silenced a warning that some
+	compilers gave about the excessively long constant for
+	JULIAN_SEC_POSIX_EPOCH.  Also fixed a bug where [clock format]
+	would fail in the :localtime zone for times before the Posix
+	Epoch.  Thanks to Miguel Sofer for pointing out all of these.
 
 2005-11-29  Kevin Kenny  <kennykb@acm.org>
 
diff --git a/generic/tclClock.c b/generic/tclClock.c
index 891ea25..340a06c 100644
--- a/generic/tclClock.c
+++ b/generic/tclClock.c
@@ -12,7 +12,7 @@
  * See the file "license.terms" for information on usage and redistribution of
  * this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tclClock.c,v 1.45 2005/11/30 15:09:41 kennykb Exp $
+ * RCS: @(#) $Id: tclClock.c,v 1.46 2005/11/30 15:39:37 kennykb Exp $
  */
 
 #include "tclInt.h"
@@ -575,6 +575,7 @@ ConvertLocalToUTCUsingC(
 ) {
     struct tm timeVal;
     int localErrno;
+    int secondOfDay;
 
     /* Convert the given time to a date */
 
@@ -588,9 +589,13 @@ ConvertLocalToUTCUsingC(
     timeVal.tm_year = fields->year - 1900;
     timeVal.tm_mon = fields->month - 1;
     timeVal.tm_mday = fields->dayOfMonth;
-    timeVal.tm_hour = (int)((fields->localSeconds / 3600) % 24);
-    timeVal.tm_min = (int)((fields->localSeconds / 60) % 60);
-    timeVal.tm_sec = (int)(fields->localSeconds % 60);
+    secondOfDay = (int)(fields->localSeconds % SECONDS_PER_DAY);
+    if (secondOfDay < 0) {
+	secondOfDay += SECONDS_PER_DAY;
+    }
+    timeVal.tm_hour = (secondOfDay / 3600) % 24;
+    timeVal.tm_min = (secondOfDay / 60) % 60;
+    timeVal.tm_sec = secondOfDay % 60;
     timeVal.tm_isdst = -1;
     timeVal.tm_wday = -1;
     timeVal.tm_yday = -1;