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#include "sofa.h"
#include <string.h>
int iauD2dtf(const char *scale, int ndp, double d1, double d2,
int *iy, int *im, int *id, int ihmsf[4])
/*
** - - - - - - - - -
** i a u D 2 d t f
** - - - - - - - - -
**
** Format for output a 2-part Julian Date (or in the case of UTC a
** quasi-JD form that includes special provision for leap seconds).
**
** This function is part of the International Astronomical Union's
** SOFA (Standards of Fundamental Astronomy) software collection.
**
** Status: support function.
**
** Given:
** scale char[] time scale ID (Note 1)
** ndp int resolution (Note 2)
** d1,d2 double time as a 2-part Julian Date (Notes 3,4)
**
** Returned:
** iy,im,id int year, month, day in Gregorian calendar (Note 5)
** ihmsf int[4] hours, minutes, seconds, fraction (Note 1)
**
** Returned (function value):
** int status: +1 = dubious year (Note 5)
** 0 = OK
** -1 = unacceptable date (Note 6)
**
** Notes:
**
** 1) scale identifies the time scale. Only the value "UTC" (in upper
** case) is significant, and enables handling of leap seconds (see
** Note 4).
**
** 2) ndp is the number of decimal places in the seconds field, and can
** have negative as well as positive values, such as:
**
** ndp resolution
** -4 1 00 00
** -3 0 10 00
** -2 0 01 00
** -1 0 00 10
** 0 0 00 01
** 1 0 00 00.1
** 2 0 00 00.01
** 3 0 00 00.001
**
** The limits are platform dependent, but a safe range is -5 to +9.
**
** 3) d1+d2 is Julian Date, apportioned in any convenient way between
** the two arguments, for example where d1 is the Julian Day Number
** and d2 is the fraction of a day. In the case of UTC, where the
** use of JD is problematical, special conventions apply: see the
** next note.
**
** 4) JD cannot unambiguously represent UTC during a leap second unless
** special measures are taken. The SOFA internal convention is that
** the quasi-JD day represents UTC days whether the length is 86399,
** 86400 or 86401 SI seconds. In the 1960-1972 era there were
** smaller jumps (in either direction) each time the linear UTC(TAI)
** expression was changed, and these "mini-leaps" are also included
** in the SOFA convention.
**
** 5) The warning status "dubious year" flags UTCs that predate the
** introduction of the time scale or that are too far in the future
** to be trusted. See iauDat for further details.
**
** 6) For calendar conventions and limitations, see iauCal2jd.
**
** Called:
** iauJd2cal JD to Gregorian calendar
** iauD2tf decompose days to hms
** iauDat delta(AT) = TAI-UTC
**
** This revision: 2014 February 15
**
** SOFA release 2020-07-21
**
** Copyright (C) 2020 IAU SOFA Board. See notes at end.
*/
{
int leap;
char s;
int iy1, im1, id1, js, iy2, im2, id2, ihmsf1[4], i;
double a1, b1, fd, dat0, dat12, w, dat24, dleap;
/* The two-part JD. */
a1 = d1;
b1 = d2;
/* Provisional calendar date. */
js = iauJd2cal(a1, b1, &iy1, &im1, &id1, &fd);
if ( js ) return -1;
/* Is this a leap second day? */
leap = 0;
if ( ! strcmp(scale,"UTC") ) {
/* TAI-UTC at 0h today. */
js = iauDat(iy1, im1, id1, 0.0, &dat0);
if ( js < 0 ) return -1;
/* TAI-UTC at 12h today (to detect drift). */
js = iauDat(iy1, im1, id1, 0.5, &dat12);
if ( js < 0 ) return -1;
/* TAI-UTC at 0h tomorrow (to detect jumps). */
js = iauJd2cal(a1+1.5, b1-fd, &iy2, &im2, &id2, &w);
if ( js ) return -1;
js = iauDat(iy2, im2, id2, 0.0, &dat24);
if ( js < 0 ) return -1;
/* Any sudden change in TAI-UTC (seconds). */
dleap = dat24 - (2.0*dat12 - dat0);
/* If leap second day, scale the fraction of a day into SI. */
leap = (dleap != 0.0);
if (leap) fd += fd * dleap/DAYSEC;
}
/* Provisional time of day. */
iauD2tf ( ndp, fd, &s, ihmsf1 );
/* Has the (rounded) time gone past 24h? */
if ( ihmsf1[0] > 23 ) {
/* Yes. We probably need tomorrow's calendar date. */
js = iauJd2cal(a1+1.5, b1-fd, &iy2, &im2, &id2, &w);
if ( js ) return -1;
/* Is today a leap second day? */
if ( ! leap ) {
/* No. Use 0h tomorrow. */
iy1 = iy2;
im1 = im2;
id1 = id2;
ihmsf1[0] = 0;
ihmsf1[1] = 0;
ihmsf1[2] = 0;
} else {
/* Yes. Are we past the leap second itself? */
if ( ihmsf1[2] > 0 ) {
/* Yes. Use tomorrow but allow for the leap second. */
iy1 = iy2;
im1 = im2;
id1 = id2;
ihmsf1[0] = 0;
ihmsf1[1] = 0;
ihmsf1[2] = 0;
} else {
/* No. Use 23 59 60... today. */
ihmsf1[0] = 23;
ihmsf1[1] = 59;
ihmsf1[2] = 60;
}
/* If rounding to 10s or coarser always go up to new day. */
if ( ndp < 0 && ihmsf1[2] == 60 ) {
iy1 = iy2;
im1 = im2;
id1 = id2;
ihmsf1[0] = 0;
ihmsf1[1] = 0;
ihmsf1[2] = 0;
}
}
}
/* Results. */
*iy = iy1;
*im = im1;
*id = id1;
for ( i = 0; i < 4; i++ ) {
ihmsf[i] = ihmsf1[i];
}
/* Status. */
return js;
/*----------------------------------------------------------------------
**
** Copyright (C) 2020
** Standards Of Fundamental Astronomy Board
** of the International Astronomical Union.
**
** =====================
** SOFA Software License
** =====================
**
** NOTICE TO USER:
**
** BY USING THIS SOFTWARE YOU ACCEPT THE FOLLOWING SIX TERMS AND
** CONDITIONS WHICH APPLY TO ITS USE.
**
** 1. The Software is owned by the IAU SOFA Board ("SOFA").
**
** 2. Permission is granted to anyone to use the SOFA software for any
** purpose, including commercial applications, free of charge and
** without payment of royalties, subject to the conditions and
** restrictions listed below.
**
** 3. You (the user) may copy and distribute SOFA source code to others,
** and use and adapt its code and algorithms in your own software,
** on a world-wide, royalty-free basis. That portion of your
** distribution that does not consist of intact and unchanged copies
** of SOFA source code files is a "derived work" that must comply
** with the following requirements:
**
** a) Your work shall be marked or carry a statement that it
** (i) uses routines and computations derived by you from
** software provided by SOFA under license to you; and
** (ii) does not itself constitute software provided by and/or
** endorsed by SOFA.
**
** b) The source code of your derived work must contain descriptions
** of how the derived work is based upon, contains and/or differs
** from the original SOFA software.
**
** c) The names of all routines in your derived work shall not
** include the prefix "iau" or "sofa" or trivial modifications
** thereof such as changes of case.
**
** d) The origin of the SOFA components of your derived work must
** not be misrepresented; you must not claim that you wrote the
** original software, nor file a patent application for SOFA
** software or algorithms embedded in the SOFA software.
**
** e) These requirements must be reproduced intact in any source
** distribution and shall apply to anyone to whom you have
** granted a further right to modify the source code of your
** derived work.
**
** Note that, as originally distributed, the SOFA software is
** intended to be a definitive implementation of the IAU standards,
** and consequently third-party modifications are discouraged. All
** variations, no matter how minor, must be explicitly marked as
** such, as explained above.
**
** 4. You shall not cause the SOFA software to be brought into
** disrepute, either by misuse, or use for inappropriate tasks, or
** by inappropriate modification.
**
** 5. The SOFA software is provided "as is" and SOFA makes no warranty
** as to its use or performance. SOFA does not and cannot warrant
** the performance or results which the user may obtain by using the
** SOFA software. SOFA makes no warranties, express or implied, as
** to non-infringement of third party rights, merchantability, or
** fitness for any particular purpose. In no event will SOFA be
** liable to the user for any consequential, incidental, or special
** damages, including any lost profits or lost savings, even if a
** SOFA representative has been advised of such damages, or for any
** claim by any third party.
**
** 6. The provision of any version of the SOFA software under the terms
** and conditions specified herein does not imply that future
** versions will also be made available under the same terms and
** conditions.
*
** In any published work or commercial product which uses the SOFA
** software directly, acknowledgement (see www.iausofa.org) is
** appreciated.
**
** Correspondence concerning SOFA software should be addressed as
** follows:
**
** By email: sofa@ukho.gov.uk
** By post: IAU SOFA Center
** HM Nautical Almanac Office
** UK Hydrographic Office
** Admiralty Way, Taunton
** Somerset, TA1 2DN
** United Kingdom
**
**--------------------------------------------------------------------*/
}