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Diffstat (limited to 'ast/erfa/ut1utc.c')
| -rw-r--r-- | ast/erfa/ut1utc.c | 202 |
1 files changed, 0 insertions, 202 deletions
diff --git a/ast/erfa/ut1utc.c b/ast/erfa/ut1utc.c deleted file mode 100644 index 6ec1b44..0000000 --- a/ast/erfa/ut1utc.c +++ /dev/null @@ -1,202 +0,0 @@ -#include "erfa.h" - -int eraUt1utc(double ut11, double ut12, double dut1, - double *utc1, double *utc2) -/* -** - - - - - - - - - - -** e r a U t 1 u t c -** - - - - - - - - - - -** -** Time scale transformation: Universal Time, UT1, to Coordinated -** Universal Time, UTC. -** -** Given: -** ut11,ut12 double UT1 as a 2-part Julian Date (Note 1) -** dut1 double Delta UT1: UT1-UTC in seconds (Note 2) -** -** Returned: -** utc1,utc2 double UTC as a 2-part quasi Julian Date (Notes 3,4) -** -** Returned (function value): -** int status: +1 = dubious year (Note 5) -** 0 = OK -** -1 = unacceptable date -** -** Notes: -** -** 1) ut11+ut12 is Julian Date, apportioned in any convenient way -** between the two arguments, for example where ut11 is the Julian -** Day Number and ut12 is the fraction of a day. The returned utc1 -** and utc2 form an analogous pair, except that a special convention -** is used, to deal with the problem of leap seconds - see Note 3. -** -** 2) Delta UT1 can be obtained from tabulations provided by the -** International Earth Rotation and Reference Systems Service. The -** value changes abruptly by 1s at a leap second; however, close to -** a leap second the algorithm used here is tolerant of the "wrong" -** choice of value being made. -** -** 3) JD cannot unambiguously represent UTC during a leap second unless -** special measures are taken. The convention in the present -** function is that the returned quasi JD day UTC1+UTC2 represents -** UTC days whether the length is 86399, 86400 or 86401 SI seconds. -** -** 4) The function eraD2dtf can be used to transform the UTC quasi-JD -** into calendar date and clock time, including UTC leap second -** handling. -** -** 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 eraDat for further details. -** -** Called: -** eraJd2cal JD to Gregorian calendar -** eraDat delta(AT) = TAI-UTC -** eraCal2jd Gregorian calendar to JD -** -** 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) -** -** Copyright (C) 2013-2016, NumFOCUS Foundation. -** Derived, with permission, from the SOFA library. See notes at end of file. -*/ -{ - int big1; - int i, iy, im, id, js; - double duts, u1, u2, d1, dats1, d2, fd, dats2, ddats, us1, us2, du; - - -/* UT1-UTC in seconds. */ - duts = dut1; - -/* Put the two parts of the UT1 into big-first order. */ - big1 = ( ut11 >= ut12 ); - if ( big1 ) { - u1 = ut11; - u2 = ut12; - } else { - u1 = ut12; - u2 = ut11; - } - -/* See if the UT1 can possibly be in a leap-second day. */ - d1 = u1; - dats1 = 0; - for ( i = -1; i <= 3; i++ ) { - d2 = u2 + (double) i; - if ( eraJd2cal(d1, d2, &iy, &im, &id, &fd) ) return -1; - js = eraDat(iy, im, id, 0.0, &dats2); - if ( js < 0 ) return -1; - if ( i == - 1 ) dats1 = dats2; - ddats = dats2 - dats1; - if ( fabs(ddats) >= 0.5 ) { - - /* Yes, leap second nearby: ensure UT1-UTC is "before" value. */ - if ( ddats * duts >= 0 ) duts -= ddats; - - /* UT1 for the start of the UTC day that ends in a leap. */ - if ( eraCal2jd(iy, im, id, &d1, &d2) ) return -1; - us1 = d1; - us2 = d2 - 1.0 + duts/ERFA_DAYSEC; - - /* Is the UT1 after this point? */ - du = u1 - us1; - du += u2 - us2; - if ( du > 0 ) { - - /* Yes: fraction of the current UTC day that has elapsed. */ - fd = du * ERFA_DAYSEC / ( ERFA_DAYSEC + ddats ); - - /* Ramp UT1-UTC to bring about ERFA's JD(UTC) convention. */ - duts += ddats * ( fd <= 1.0 ? fd : 1.0 ); - } - - /* Done. */ - break; - } - dats1 = dats2; - } - -/* Subtract the (possibly adjusted) UT1-UTC from UT1 to give UTC. */ - u2 -= duts / ERFA_DAYSEC; - -/* Result, safeguarding precision. */ - if ( big1 ) { - *utc1 = u1; - *utc2 = u2; - } else { - *utc1 = u2; - *utc2 = u1; - } - -/* 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. -** -*/ |