Imported from /home/lorry/working-area/delta_ntp/ntp-dev-4.2.7p482.tar.gz.ntp-dev-4.2.7p482

1 files changed, 68 insertions, 0 deletions

diff --git a/libntp/caltontp.c b/libntp/caltontp.c
new file mode 100644
index 0000000..4246a6a
--- /dev/null
+++ b/libntp/caltontp.c
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+/*
+ * caltontp - convert a date to an NTP time
+ */
+#include <config.h>
+#include <sys/types.h>
+
+#include "ntp_types.h"
+#include "ntp_calendar.h"
+#include "ntp_stdlib.h"
+#include "ntp_assert.h"
+#include "ntp_unixtime.h"
+
+/*
+ * Juergen Perlinger, 2008-11-12
+ * Add support for full calendar calculatios. If the day-of-year is provided
+ * (that is, not zero) it will be used instead of month and day-of-month;
+ * otherwise a full turn through the calendar calculations will be taken.
+ *
+ * I know that Harlan Stenn likes to see assertions in production code, and I
+ * agree there, but it would be a tricky thing here. The algorithm is quite
+ * capable of producing sensible answers even to seemingly weird inputs: the
+ * date <any year here>-03-00, the 0.th March of the year, will be automtically
+ * treated as the last day of February, no matter whether the year is a leap
+ * year or not. So adding constraints is merely for the benefit of the callers,
+ * because the only thing we can check for consistency is our input, produced
+ * by somebody else.
+ *
+ * BTW: A total roundtrip using 'caljulian' would be a quite shaky thing:
+ * Because of the truncation of the NTP time stamp to 32 bits and the epoch
+ * unfolding around the current time done by 'caljulian' the roundtrip does
+ * *not* necessarily reproduce the input, especially if the time spec is more
+ * than 68 years off from the current time...
+ */
+
+uint32_t
+caltontp(
+	const struct calendar *jt
+	)
+{
+	int32_t eraday;	/* CE Rata Die number	*/
+	vint64  ntptime;/* resulting NTP time	*/
+
+	NTP_INSIST(jt != NULL);
+
+	NTP_REQUIRE(jt->month <= 13);	/* permit month 0..13! */
+	NTP_REQUIRE(jt->monthday <= 32);
+	NTP_REQUIRE(jt->yearday <= 366);
+	NTP_REQUIRE(jt->hour <= 24);
+	NTP_REQUIRE(jt->minute <= MINSPERHR);
+	NTP_REQUIRE(jt->second <= SECSPERMIN);
+
+	/*
+	 * First convert the date to he corresponding RataDie
+	 * number. If yearday is not zero, assume that it contains a
+	 * useable value and avoid all calculations involving month
+	 * and day-of-month. Do a full evaluation otherwise.
+	 */
+	if (jt->yearday)
+		eraday = ntpcal_year_to_ystart(jt->year)
+		       + jt->yearday - 1;
+	else
+		eraday = ntpcal_date_to_rd(jt);
+
+	ntptime = ntpcal_dayjoin(eraday - DAY_NTP_STARTS,
+				 ntpcal_etime_to_seconds(jt->hour, jt->minute,
+							 jt->second));
+	return ntptime.d_s.lo;
+}