NASA Ocean Color

ocssw V2022

 #include <stdio.h>
 #include <stdint.h>
 #include <timeutils.h>
  
 int jdate(int32_t julianDay, int32_t *year, int32_t *dayOfYear) {
  
     int32_t month, day;
     int32_t ja, jb, jc, jd, je, jalpha;
  
     jalpha = (int32_t) (((julianDay - 1867216L) - 0.25) / 36524.25);
     ja = julianDay + 1 + jalpha - (int32_t) (0.25 * jalpha);
  
     jb = ja + 1524;
     jc = (int32_t) (6680.0 + ((jb - 2439870L) - 122.1) / 365.25);
     jd = 365 * jc + (int32_t) (0.25 * jc);
     je = (int32_t) ((jb - jd) / 30.6001);
  
     day = jb - jd - (int32_t) (30.6001 * je);
     month = je - 1;
     if (month > 12)
         month = month - 12;
     *year = jc - 4715;
  
     if (month > 2) 
         *year = *year - 1;
     if (*year <= 0)
         *year = *year - 1;
  
     int numDaysEachMonth[24] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31,
         31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
  
     *dayOfYear = day;
     for (int idxMonth = 1; idxMonth < month; idxMonth++) 
         *dayOfYear = *dayOfYear + numDaysEachMonth[isleap(*year) * 12 + (idxMonth - 1)];
  
     return 0;
 }