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#include "sofa.h"
int iauJdcalf(int ndp, double dj1, double dj2, int iymdf[4])
/*
** - - - - - - - - - -
** i a u J d c a l f
** - - - - - - - - - -
**
** Julian Date to Gregorian Calendar, expressed in a form convenient
** for formatting messages: rounded to a specified precision.
**
** This function is part of the International Astronomical Union's
** SOFA (Standards Of Fundamental Astronomy) software collection.
**
** Status: support function.
**
** Given:
** ndp int number of decimal places of days in fraction
** dj1,dj2 double dj1+dj2 = Julian Date (Note 1)
**
** Returned:
** iymdf int[4] year, month, day, fraction in Gregorian
** calendar
**
** Returned (function value):
** int status:
** -1 = date out of range
** 0 = OK
** +1 = NDP not 0-9 (interpreted as 0)
**
** Notes:
**
** 1) The Julian Date is apportioned in any convenient way between
** the arguments dj1 and dj2. For example, JD=2450123.7 could
** be expressed in any of these ways, among others:
**
** dj1 dj2
**
** 2450123.7 0.0 (JD method)
** 2451545.0 -1421.3 (J2000 method)
** 2400000.5 50123.2 (MJD method)
** 2450123.5 0.2 (date & time method)
**
** 2) In early eras the conversion is from the "Proleptic Gregorian
** Calendar"; no account is taken of the date(s) of adoption of
** the Gregorian Calendar, nor is the AD/BC numbering convention
** observed.
**
** 3) Refer to the function iauJd2cal.
**
** 4) NDP should be 4 or less if internal overflows are to be
** avoided on machines which use 16-bit integers.
**
** Called:
** iauJd2cal JD to Gregorian calendar
**
** Reference:
**
** Explanatory Supplement to the Astronomical Almanac,
** P. Kenneth Seidelmann (ed), University Science Books (1992),
** Section 12.92 (p604).
**
** This revision: 2020 April 13
**
** SOFA release 2020-07-21
**
** Copyright (C) 2020 IAU SOFA Board. See notes at end.
*/
{
int j, js;
double denom, d1, d2, f1, f2, d, djd, f, rf;
/* Denominator of fraction (e.g. 100 for 2 decimal places). */
if ((ndp >= 0) && (ndp <= 9)) {
j = 0;
denom = pow(10.0, ndp);
} else {
j = 1;
denom = 1.0;
}
/* Copy the date, big then small. */
if (fabs(dj1) >= fabs(dj2)) {
d1 = dj1;
d2 = dj2;
} else {
d1 = dj2;
d2 = dj1;
}
/* Realign to midnight (without rounding error). */
d1 -= 0.5;
/* Separate day and fraction (as precisely as possible). */
d = dnint(d1);
f1 = d1 - d;
djd = d;
d = dnint(d2);
f2 = d2 - d;
djd += d;
d = dnint(f1 + f2);
f = (f1 - d) + f2;
if (f < 0.0) {
f += 1.0;
d -= 1.0;
}
djd += d;
/* Round the total fraction to the specified number of places. */
rf = dnint(f*denom) / denom;
/* Re-align to noon. */
djd += 0.5;
/* Convert to Gregorian calendar. */
js = iauJd2cal(djd, rf, &iymdf[0], &iymdf[1], &iymdf[2], &f);
if (js == 0) {
iymdf[3] = (int) dnint(f * denom);
} else {
j = js;
}
/* Return the status. */
return j;
/*----------------------------------------------------------------------
**
** 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
**
**--------------------------------------------------------------------*/
}