1 files changed, 59 insertions, 0 deletions
diff --git a/contrib/ntp/libntp/calleapwhen.c b/contrib/ntp/libntp/calleapwhen.c
new file mode 100644
index 0000000..c954901
--- /dev/null
+++ b/contrib/ntp/libntp/calleapwhen.c
@@ -0,0 +1,59 @@
+/*
+ * calleapwhen - determine the number of seconds to the next possible
+ *		 leap occurance.
+ */
+#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 */
+};
+
+u_long
+calleapwhen(
+	u_long ntpdate
+	)
+{
+	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.
+	 */
+	return (u_long)(calleaptab[i] - (long)dateincycle);
+}