1 files changed, 61 insertions, 0 deletions
diff --git a/usr.sbin/xntpd/lib/calleapwhen.c b/usr.sbin/xntpd/lib/calleapwhen.c
new file mode 100644
index 000000000000..379643f09566
--- /dev/null
+++ b/usr.sbin/xntpd/lib/calleapwhen.c
@@ -0,0 +1,61 @@
+/* calleapwhen.c,v 3.1 1993/07/06 01:08:02 jbj Exp
+ * calleapwhen - determine the number of seconds to the next possible
+ *		 leap occurance and the last one.
+ */
+#include <sys/types.h>
+
+#include "ntp_types.h"
+#include "ntp_calendar.h"
+#include "ntp_stdlib.h"
+
+/*
+ * calleaptab - leaps occur at the end of December and June
+ */
+LONG calleaptab[10] = {
+	-(JAN+FEBLEAP)*SECSPERDAY,	/* leap previous to cycle */
+	(MAR+APR+MAY+JUN)*SECSPERDAY,	/* end of June */
+	(MAR+APR+MAY+JUN+JUL+AUG+SEP+OCT+NOV+DEC)*SECSPERDAY, /* end of Dec */
+	(MAR+APR+MAY+JUN)*SECSPERDAY + SECSPERYEAR,
+	(MAR+APR+MAY+JUN+JUL+AUG+SEP+OCT+NOV+DEC)*SECSPERDAY + SECSPERYEAR,
+	(MAR+APR+MAY+JUN)*SECSPERDAY + 2*SECSPERYEAR,
+	(MAR+APR+MAY+JUN+JUL+AUG+SEP+OCT+NOV+DEC)*SECSPERDAY + 2*SECSPERYEAR,
+	(MAR+APR+MAY+JUN)*SECSPERDAY + 3*SECSPERYEAR,
+	(MAR+APR+MAY+JUN+JUL+AUG+SEP+OCT+NOV+DEC)*SECSPERDAY + 3*SECSPERYEAR,
+	(MAR+APR+MAY+JUN+JUL+AUG+SEP+OCT+NOV+DEC+JAN+FEBLEAP+MAR+APR+MAY+JUN)
+	    *SECSPERDAY + 3*SECSPERYEAR,	/* next after current cycle */
+};
+
+void
+calleapwhen(ntpdate, leaplast, leapnext)
+	U_LONG ntpdate;
+	U_LONG *leaplast;
+	U_LONG *leapnext;
+{
+	register U_LONG dateincycle;
+	register int i;
+
+	/*
+	 * Find the offset from the start of the cycle
+	 */
+	dateincycle = ntpdate;
+	if (dateincycle >= MAR1988)
+		dateincycle -= MAR1988;
+	else
+		dateincycle -= MAR1900;
+
+	while (dateincycle >= SECSPERCYCLE)
+		dateincycle -= SECSPERCYCLE;
+
+	/*
+	 * Find where we are with respect to the leap events.
+	 */
+	for (i = 1; i < 9; i++)
+		if (dateincycle < (U_LONG)calleaptab[i])
+			break;
+	
+	/*
+	 * i points at the next leap.  Compute the last and the next.
+	 */
+	*leaplast = (U_LONG)((LONG)dateincycle - calleaptab[i-1]);
+	*leapnext = (U_LONG)(calleaptab[i] - (LONG)dateincycle);
+}