int eraUtctai	(	double	utc1,
		double	utc2,
		double *	tai1,
		double *	tai2
	)

Definition at line 3 of file utctai.c.

References eraCal2jd(), eraDat(), eraJd2cal(), ERFA_DAYSEC, and id.

Referenced by eraApco13(), eraApio13(), eraTaiutc(), eraUtcut1(), and t_utctai().

{
   int big1;
   int iy, im, id, j, iyt, imt, idt;
   double u1, u2, fd, dat0, dat12, w, dat24, dlod, dleap, z1, z2, a2;

/* Put the two parts of the UTC into big-first order. */
   big1 = ( utc1 >= utc2 );
   if ( big1 ) {
      u1 = utc1;
      u2 = utc2;
   } else {
      u1 = utc2;
      u2 = utc1;
   }

/* Get TAI-UTC at 0h today. */
   j = eraJd2cal(u1, u2, &iy, &im, &id, &fd);
   if ( j ) return j;
   j = eraDat(iy, im, id, 0.0, &dat0);
   if ( j < 0 ) return j;

/* Get TAI-UTC at 12h today (to detect drift). */
   j = eraDat(iy, im, id, 0.5, &dat12);
   if ( j < 0 ) return j;

/* Get TAI-UTC at 0h tomorrow (to detect jumps). */
   j = eraJd2cal(u1+1.5, u2-fd, &iyt, &imt, &idt, &w);
   if ( j ) return j;
   j = eraDat(iyt, imt, idt, 0.0, &dat24);
   if ( j < 0 ) return j;

/* Separate TAI-UTC change into per-day (DLOD) and any jump (DLEAP). */
   dlod = 2.0 * (dat12 - dat0);
   dleap = dat24 - (dat0 + dlod);

/* Remove any scaling applied to spread leap into preceding day. */
   fd *= (ERFA_DAYSEC+dleap)/ERFA_DAYSEC;

/* Scale from (pre-1972) UTC seconds to SI seconds. */
   fd *= (ERFA_DAYSEC+dlod)/ERFA_DAYSEC;

/* Today's calendar date to 2-part JD. */
   if ( eraCal2jd(iy, im, id, &z1, &z2) ) return -1;

/* Assemble the TAI result, preserving the UTC split and order. */
   a2 = z1 - u1;
   a2 += z2;
   a2 += fd + dat0/ERFA_DAYSEC;
   if ( big1 ) {
      *tai1 = u1;
      *tai2 = a2;
   } else {
      *tai1 = a2;
      *tai2 = u1;
   }

/* Status. */
   return j;

}

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