Diff: udp/ntp/ntptimestamp.c

Revision:

124:6e558721ec1c

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/udp/ntp/ntptimestamp.c	Fri Feb 22 08:41:47 2019 +0000
@@ -0,0 +1,36 @@
+#include <stdint.h>
+#include <stdbool.h>
+
+#include "clktime.h"
+#include "clkutc.h"
+
+#define SECONDS_BETWEEN_1900_AND_1970 2208988800ULL
+
+#define ERA_BASE_LOW 1LL //Adjust this from 0 to 1 between 1968 and 2036; 1 to 2 between 2104 and 2168
+#define ERA_BASE_HGH 0LL //Adjust this from 0 to 1 between 2036 and 2104; 1 to 2 between 2172 and 2240
+
+uint64_t NtpTimeStampFromClkTime(clktime tai)
+{
+    clktime utc = ClkUtcFromTai(tai);
+    uint64_t timestamp = utc << (32 - CLK_TIME_ONE_SECOND_SHIFT);
+    
+    timestamp += SECONDS_BETWEEN_1900_AND_1970 << 32; //This should just wrap around the unsigned timestamp removing the unwanted era.
+    
+    return timestamp;
+}
+clktime NtpTimeStampToClkTime(uint64_t timestamp)
+{
+    bool isHigh = (timestamp & (1ULL << 63)) != 0;
+    
+    clktime utc = timestamp - (SECONDS_BETWEEN_1900_AND_1970 << 32);
+    utc >>= (32 - CLK_TIME_ONE_SECOND_SHIFT);
+    
+    //Correct for era
+    if (isHigh) utc += ERA_BASE_HGH << (32 + CLK_TIME_ONE_SECOND_SHIFT);
+    else        utc += ERA_BASE_LOW << (32 + CLK_TIME_ONE_SECOND_SHIFT);
+    
+    clktime tai = ClkUtcToTai(utc);
+    
+    return tai;
+}
+