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#include "sofa.h"
int iauCal2jd(int iy, int im, int id, double *djm0, double *djm)
/*
** - - - - - - - - - -
** i a u C a l 2 j d
** - - - - - - - - - -
**
** Gregorian Calendar to Julian Date.
**
** This function is part of the International Astronomical Union's
** SOFA (Standards Of Fundamental Astronomy) software collection.
**
** Status: support function.
**
** Given:
** iy,im,id int year, month, day in Gregorian calendar (Note 1)
**
** Returned:
** djm0 double MJD zero-point: always 2400000.5
** djm double Modified Julian Date for 0 hrs
**
** Returned (function value):
** int status:
** 0 = OK
** -1 = bad year (Note 3: JD not computed)
** -2 = bad month (JD not computed)
** -3 = bad day (JD computed)
**
** Notes:
**
** 1) The algorithm used is valid from -4800 March 1, but this
** implementation rejects dates before -4799 January 1.
**
** 2) The Julian Date is returned in two pieces, in the usual SOFA
** manner, which is designed to preserve time resolution. The
** Julian Date is available as a single number by adding djm0 and
** djm.
**
** 3) 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.
**
** Reference:
**
** Explanatory Supplement to the Astronomical Almanac,
** P. Kenneth Seidelmann (ed), University Science Books (1992),
** Section 12.92 (p604).
**
** This revision: 2013 August 7
**
** SOFA release 2020-07-21
**
** Copyright (C) 2020 IAU SOFA Board. See notes at end.
*/
{
int j, ly, my;
long iypmy;
/* Earliest year allowed (4800BC) */
const int IYMIN = -4799;
/* Month lengths in days */
static const int mtab[]
= {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
/* Preset status. */
j = 0;
/* Validate year and month. */
if (iy < IYMIN) return -1;
if (im < 1 || im > 12) return -2;
/* If February in a leap year, 1, otherwise 0. */
ly = ((im == 2) && !(iy%4) && (iy%100 || !(iy%400)));
/* Validate day, taking into account leap years. */
if ( (id < 1) || (id > (mtab[im-1] + ly))) j = -3;
/* Return result. */
my = (im - 14) / 12;
iypmy = (long) (iy + my);
*djm0 = DJM0;
*djm = (double)((1461L * (iypmy + 4800L)) / 4L
+ (367L * (long) (im - 2 - 12 * my)) / 12L
- (3L * ((iypmy + 4900L) / 100L)) / 4L
+ (long) id - 2432076L);
/* Return 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
**
**--------------------------------------------------------------------*/
}