NASA Ocean Color

ocssw V2022

 #include <stdint.h>
 #include <timeutils.h>
  
 double yds2tai93(int16_t iyr, int16_t idy, double sec) {
     // add the seconds after the conversion to TAI93 so the leap second 
     // is not lost
     double unixTime = yds2unix(iyr, idy, 0.0);
     return unix_to_tai93(unixTime) + sec;
 }
  
 double unix_to_tai93(double unixtime) {
     double tai93 = unixtime - 725846400; // seconds between 1970 and 1993
     return tai93 + leapseconds_since_1993_unix(unixtime); // TAI includes leap seconds
 }
  
 double tai93_to_unix(double tai93) {
     double unixtime = tai93 - leapseconds_since_1993(tai93);
     return unixtime + 725846400;
 }
  
 // The TAI58 routines will have the wrong number of leap seconds
 // for times before 1993.
 double unix_to_tai58(double unixtime) {
     // seconds between UTC 1993 and UTC 1958 = 1104537600
     // plus leap seconds between 1993 and 1958 = 27
     return unix_to_tai93(unixtime) + 1104537600.0 + 27.0;
 }
  
 double tai58_to_unix(double tai58) {
     return tai93_to_unix(tai58 - 1104537600.0 - 27.0);
 }