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#include "erfa.h"
int eraUtcut1(double utc1, double utc2, double dut1,
double *ut11, double *ut12)
/*
** - - - - - - - - - -
** e r a U t c u t 1
** - - - - - - - - - -
**
** Time scale transformation: Coordinated Universal Time, UTC, to
** Universal Time, UT1.
**
** Given:
** utc1,utc2 double UTC as a 2-part quasi Julian Date (Notes 1-4)
** dut1 double Delta UT1 = UT1-UTC in seconds (Note 5)
**
** Returned:
** ut11,ut12 double UT1 as a 2-part Julian Date (Note 6)
**
** Returned (function value):
** int status: +1 = dubious year (Note 3)
** 0 = OK
** -1 = unacceptable date
**
** Notes:
**
** 1) utc1+utc2 is quasi Julian Date (see Note 2), apportioned in any
** convenient way between the two arguments, for example where utc1
** is the Julian Day Number and utc2 is the fraction of a day.
**
** 2) JD cannot unambiguously represent UTC during a leap second unless
** special measures are taken. The convention in the present
** function is that the JD day represents UTC days whether the
** length is 86399, 86400 or 86401 SI seconds.
**
** 3) 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 eraDat for further details.
**
** 4) The function eraDtf2d converts from calendar date and time of
** day into 2-part Julian Date, and in the case of UTC implements
** the leap-second-ambiguity convention described above.
**
** 5) Delta UT1 can be obtained from tabulations provided by the
** International Earth Rotation and Reference Systems Service.
** It is the caller's responsibility to supply a dut1 argument
** containing the UT1-UTC value that matches the given UTC.
**
** 6) The returned ut11,ut12 are such that their sum is the UT1 Julian
** Date.
**
** References:
**
** McCarthy, D. D., Petit, G. (eds.), IERS Conventions (2003),
** IERS Technical Note No. 32, BKG (2004)
**
** Explanatory Supplement to the Astronomical Almanac,
** P. Kenneth Seidelmann (ed), University Science Books (1992)
**
** Called:
** eraJd2cal JD to Gregorian calendar
** eraDat delta(AT) = TAI-UTC
** eraUtctai UTC to TAI
** eraTaiut1 TAI to UT1
**
** Copyright (C) 2013-2016, NumFOCUS Foundation.
** Derived, with permission, from the SOFA library. See notes at end of file.
*/
{
int iy, im, id, js, jw;
double w, dat, dta, tai1, tai2;
/* Look up TAI-UTC. */
if ( eraJd2cal(utc1, utc2, &iy, &im, &id, &w) ) return -1;
js = eraDat ( iy, im, id, 0.0, &dat);
if ( js < 0 ) return -1;
/* Form UT1-TAI. */
dta = dut1 - dat;
/* UTC to TAI to UT1. */
jw = eraUtctai(utc1, utc2, &tai1, &tai2);
if ( jw < 0 ) {
return -1;
} else if ( jw > 0 ) {
js = jw;
}
if ( eraTaiut1(tai1, tai2, dta, ut11, ut12) ) return -1;
/* Status. */
return js;
}
/*----------------------------------------------------------------------
**
**
** Copyright (C) 2013-2016, NumFOCUS Foundation.
** All rights reserved.
**
** This library is derived, with permission, from the International
** Astronomical Union's "Standards of Fundamental Astronomy" library,
** available from http://www.iausofa.org.
**
** The ERFA version is intended to retain identical functionality to
** the SOFA library, but made distinct through different function and
** file names, as set out in the SOFA license conditions. The SOFA
** original has a role as a reference standard for the IAU and IERS,
** and consequently redistribution is permitted only in its unaltered
** state. The ERFA version is not subject to this restriction and
** therefore can be included in distributions which do not support the
** concept of "read only" software.
**
** Although the intent is to replicate the SOFA API (other than
** replacement of prefix names) and results (with the exception of
** bugs; any that are discovered will be fixed), SOFA is not
** responsible for any errors found in this version of the library.
**
** If you wish to acknowledge the SOFA heritage, please acknowledge
** that you are using a library derived from SOFA, rather than SOFA
** itself.
**
**
** TERMS AND CONDITIONS
**
** Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions
** are met:
**
** 1 Redistributions of source code must retain the above copyright
** notice, this list of conditions and the following disclaimer.
**
** 2 Redistributions in binary form must reproduce the above copyright
** notice, this list of conditions and the following disclaimer in
** the documentation and/or other materials provided with the
** distribution.
**
** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
** the International Astronomical Union nor the names of its
** contributors may be used to endorse or promote products derived
** from this software without specific prior written permission.
**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
** POSSIBILITY OF SUCH DAMAGE.
**
*/
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