1 files changed, 88 insertions, 0 deletions
diff --git a/libntp/calyearstart.c b/libntp/calyearstart.c
new file mode 100644
index 0000000..9e3f58f
--- /dev/null
+++ b/libntp/calyearstart.c
@@ -0,0 +1,88 @@
+/*
+ * calyearstart - determine the NTP time at midnight of January 1 in
+ *		  the year of the given date.
+ */
+#include <config.h>
+#include <sys/types.h>
+
+#include "ntp_types.h"
+#include "ntp_calendar.h"
+#include "ntp_stdlib.h"
+#include "ntp_assert.h"
+
+/*
+ * Juergen Perlinger, 2010-05-02
+ *
+ * Redone in terms of the calendar functions. It's rather simple:
+ * - expand the NTP time stamp
+ * - split into days and seconds since midnight, dropping the partial day
+ * - get full number of days before year start in NTP epoch
+ * - convert to seconds, truncated to 32 bits.
+ */
+u_int32
+calyearstart(u_int32 ntptime, const time_t *pivot)
+{
+	u_int32      ndays; /* elapsed days since NTP starts */
+	vint64       vlong;
+	ntpcal_split split;
+
+	vlong = ntpcal_ntp_to_ntp(ntptime, pivot);
+	split = ntpcal_daysplit(&vlong);
+	ndays = ntpcal_rd_to_ystart(split.hi + DAY_NTP_STARTS)
+	      - DAY_NTP_STARTS;
+
+	return (u_int32)(ndays * SECSPERDAY);
+}
+
+/*
+ * calmonthstart - get NTP time at midnight of the first day of the
+ * current month.
+ */
+u_int32
+calmonthstart(u_int32 ntptime, const time_t *pivot)
+{
+	u_int32      ndays; /* elapsed days since NTP starts */
+	vint64       vlong;
+	ntpcal_split split;
+
+	vlong = ntpcal_ntp_to_ntp(ntptime, pivot);
+	split = ntpcal_daysplit(&vlong);
+	ndays = ntpcal_rd_to_mstart(split.hi + DAY_NTP_STARTS)
+	      - DAY_NTP_STARTS;
+
+	return (u_int32)(ndays * SECSPERDAY);
+}
+
+/*
+ * calweekstart - get NTP time at midnight of the last monday on or
+ * before the current date.
+ */
+u_int32
+calweekstart(u_int32 ntptime, const time_t *pivot)
+{
+	u_int32      ndays; /* elapsed days since NTP starts */
+	vint64       vlong;
+	ntpcal_split split;
+
+	vlong = ntpcal_ntp_to_ntp(ntptime, pivot);
+	split = ntpcal_daysplit(&vlong);
+	ndays = ntpcal_weekday_le(split.hi + DAY_NTP_STARTS, CAL_MONDAY)
+	      - DAY_NTP_STARTS;
+
+	return (u_int32)(ndays * SECSPERDAY);
+}
+
+/*
+ * caldaystart - get NTP time at midnight of the current day.
+ */
+u_int32
+caldaystart(u_int32 ntptime, const time_t *pivot)
+{
+	vint64       vlong;
+	ntpcal_split split;
+
+	vlong = ntpcal_ntp_to_ntp(ntptime, pivot);
+	split = ntpcal_daysplit(&vlong);
+	
+	return ntptime - split.lo;
+}