double palDat ( double dju ) {
int iy;
int im;
int id;
int status;
double fd;
double deltat;
iauJd2cal( PAL__MJD0, dju,
&iy, &im, &id, &fd );
status = iauDat( iy, im, id, fd, &deltat );
return deltat;
}
int iauUt1utc(double ut11, double ut12, double dut1,
double *utc1, double *utc2)
/*
** - - - - - - - - - -
** i a u U t 1 u t c
** - - - - - - - - - -
**
** Time scale transformation: Universal Time, UT1, to Coordinated
** Universal Time, UTC.
**
** Status: canonical.
**
** 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 iauD2dtf 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 and that are too far in the future
** to be trusted. See iauDat for further details.
**
** Called:
** iauJd2cal JD to Gregorian calendar
** iauDat delta(AT) = TAI-UTC
** iauCal2jd 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)
**
** This revision: 2011 May 14
**
** Original version 2012-03-01
**
** Copyright (C) 2013 Naoki Arita. See notes at end.
*/
{
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 ( iauJd2cal(d1, d2, &iy, &im, &id, &fd) ) return -1;
js = iauDat(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 ( iauCal2jd(iy, im, id, &d1, &d2) ) return -1;
us1 = d1;
us2 = d2 - 1.0 + duts/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 * DAYSEC / ( DAYSEC + ddats );
/* Ramp UT1-UTC to bring about SOFA'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 / DAYSEC;
/* Result, safeguarding precision. */
if ( big1 ) {
*utc1 = u1;
*utc2 = u2;
} else {
*utc1 = u2;
*utc2 = u1;
}
/* Status. */
return js;
/*----------------------------------------------------------------------
**
** Celes is a wrapper of the SOFA Library for Ruby.
**
** This file is redistributed and relicensed in accordance with
** the SOFA Software License (http://www.iausofa.org/tandc.html).
**
** The original library is available from IAU Standards of
** Fundamental Astronomy (http://www.iausofa.org/).
**
**
**
**
**
** Copyright (C) 2013, Naoki Arita
** All rights reserved.
**
** 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.
**
**--------------------------------------------------------------------*/
}
int iauDtf2d(const char *scale, int iy, int im, int id,
int ihr, int imn, double sec, double *d1, double *d2)
/*
** - - - - - - - - -
** i a u D t f 2 d
** - - - - - - - - -
**
** Encode date and time fields into 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)
** iy,im,id int year, month, day in Gregorian calendar (Note 2)
** ihr,imn int hour, minute
** sec double seconds
**
** Returned:
** d1,d2 double 2-part Julian Date (Notes 3,4)
**
** Returned (function value):
** int status: +3 = both of next two
** +2 = time is after end of day (Note 5)
** +1 = dubious year (Note 6)
** 0 = OK
** -1 = bad year
** -2 = bad month
** -3 = bad day
** -4 = bad hour
** -5 = bad minute
** -6 = bad second (<0)
**
** 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) For calendar conventions and limitations, see iauCal2jd.
**
** 3) The sum of the results, d1+d2, is Julian Date, where normally 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 "time is after end of day" usually means that
** the sec argument is greater than 60.0. However, in a day ending
** in a leap second the limit changes to 61.0 (or 59.0 in the case
** of a negative leap second).
**
** 6) 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.
**
** 7) Only in the case of continuous and regular time scales (TAI, TT,
** TCG, TCB and TDB) is the result d1+d2 a Julian Date, strictly
** speaking. In the other cases (UT1 and UTC) the result must be
** used with circumspection; in particular the difference between
** two such results cannot be interpreted as a precise time
** interval.
**
** Called:
** iauCal2jd Gregorian calendar to JD
** iauDat delta(AT) = TAI-UTC
** iauJd2cal JD to Gregorian calendar
**
** This revision: 2013 July 26
**
** SOFA release 2015-02-09
**
** Copyright (C) 2015 IAU SOFA Board. See notes at end.
*/
{
int js, iy2, im2, id2;
double dj, w, day, seclim, dat0, dat12, dat24, dleap, time;
/* Today's Julian Day Number. */
js = iauCal2jd(iy, im, id, &dj, &w);
if ( js ) return js;
dj += w;
/* Day length and final minute length in seconds (provisional). */
day = DAYSEC;
seclim = 60.0;
/* Deal with the UTC leap second case. */
if ( ! strcmp(scale,"UTC") ) {
/* TAI-UTC at 0h today. */
js = iauDat(iy, im, id, 0.0, &dat0);
if ( js < 0 ) return js;
/* TAI-UTC at 12h today (to detect drift). */
js = iauDat(iy, im, id, 0.5, &dat12);
if ( js < 0 ) return js;
/* TAI-UTC at 0h tomorrow (to detect jumps). */
js = iauJd2cal ( dj, 1.5, &iy2, &im2, &id2, &w);
if ( js ) return js;
js = iauDat(iy2, im2, id2, 0.0, &dat24);
if ( js < 0 ) return js;
/* Any sudden change in TAI-UTC between today and tomorrow. */
dleap = dat24 - (2.0*dat12 - dat0);
/* If leap second day, correct the day and final minute lengths. */
day += dleap;
if ( ihr == 23 && imn == 59 ) seclim += dleap;
/* End of UTC-specific actions. */
}
/* Validate the time. */
if ( ihr >= 0 && ihr <= 23 ) {
if ( imn >= 0 && imn <= 59 ) {
if ( sec >= 0 ) {
if ( sec >= seclim ) {
js += 2;
}
} else {
js = -6;
}
} else {
js = -5;
}
} else {
js = -4;
}
if ( js < 0 ) return js;
/* The time in days. */
time = ( 60.0 * ( (double) ( 60 * ihr + imn ) ) + sec ) / day;
/* Return the date and time. */
*d1 = dj;
*d2 = time;
/* Status. */
return js;
/*----------------------------------------------------------------------
**
** Copyright (C) 2015
** 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: [email protected]
** By post: IAU SOFA Center
** HM Nautical Almanac Office
** UK Hydrographic Office
** Admiralty Way, Taunton
** Somerset, TA1 2DN
** United Kingdom
**
**--------------------------------------------------------------------*/
}
int iauUtctai(double utc1, double utc2, double *tai1, double *tai2)
/*
** - - - - - - - - - -
** i a u U t c t a i
** - - - - - - - - - -
**
** Time scale transformation: Coordinated Universal Time, UTC, to
** International Atomic Time, TAI.
**
** This function is part of the International Astronomical Union's
** SOFA (Standards of Fundamental Astronomy) software collection.
**
** Status: canonical.
**
** Given:
** utc1,utc2 double UTC as a 2-part quasi Julian Date (Notes 1-4)
**
** Returned:
** tai1,tai2 double TAI as a 2-part Julian Date (Note 5)
**
** 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 and that are too far in the future
** to be trusted. See iauDat for further details.
**
** 4) The function iauDtf2d 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) The returned TAI1,TAI2 are such that their sum is the TAI Julian
** Date.
**
** Called:
** iauJd2cal JD to Gregorian calendar
** iauDat delta(AT) = TAI-UTC
** iauCal2jd 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)
**
** This revision: 2010 September 10
**
** SOFA release 2012-03-01
**
** Copyright (C) 2012 IAU SOFA Board. See notes at end.
**
*/
{
int big1;
int iy, im, id, js, iyt, imt, idt;
double u1, u2, fd, dats, fdt, datst, ddat, z1, z2, a2;
/* Put the two parts of the UTC into big-first order. */
big1 = ( utc1 >= utc2 );
if ( big1 ) {
u1 = utc1;
u2 = utc2;
} else {
u1 = utc2;
u2 = utc1;
}
/* Get TAI-UTC now. */
if ( iauJd2cal(u1, u2, &iy, &im, &id, &fd) ) return -1;
js = iauDat(iy, im, id, fd, &dats);
if ( js < 0 ) return -1;
/* Get TAI-UTC tomorrow. */
if ( iauJd2cal(u1+1.5, u2-fd, &iyt, &imt, &idt, &fdt) ) return -1;
js = iauDat(iyt, imt, idt, fdt, &datst);
if ( js < 0 ) return -1;
/* If today ends in a leap second, scale the fraction into SI days. */
ddat = datst - dats;
if ( fabs(ddat) > 0.5 ) fd += fd * ddat / DAYSEC;
/* Today's calendar date to 2-part JD. */
if ( iauCal2jd(iy, im, id, &z1, &z2) ) return -1;
/* Assemble the TAI result, preserving the UTC split and order. */
a2 = z1 - u1;
a2 += z2;
a2 += fd + dats / DAYSEC;
if ( big1 ) {
*tai1 = u1;
*tai2 = a2;
} else {
*tai1 = a2;
*tai2 = u1;
}
/* Status. */
return js;
/*----------------------------------------------------------------------
**
** Copyright (C) 2012
** 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: [email protected]
** By post: IAU SOFA Center
** HM Nautical Almanac Office
** UK Hydrographic Office
** Admiralty Way, Taunton
** Somerset, TA1 2DN
** United Kingdom
**
**--------------------------------------------------------------------*/
}
int iauUt1utc(double ut11, double ut12, double dut1,
double *utc1, double *utc2)
/*
** - - - - - - - - - -
** i a u U t 1 u t c
** - - - - - - - - - -
**
** Time scale transformation: Universal Time, UT1, to Coordinated
** Universal Time, UTC.
**
** This function is part of the International Astronomical Union's
** SOFA (Standards of Fundamental Astronomy) software collection.
**
** Status: canonical.
**
** 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 iauD2dtf 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 iauDat for further details.
**
** Called:
** iauJd2cal JD to Gregorian calendar
** iauDat delta(AT) = TAI-UTC
** iauCal2jd 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)
**
** This revision: 2013 June 18
**
** SOFA release 2017-04-20
**
** Copyright (C) 2017 IAU SOFA Board. See notes at end.
*/
{
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 ( iauJd2cal(d1, d2, &iy, &im, &id, &fd) ) return -1;
js = iauDat(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 ( iauCal2jd(iy, im, id, &d1, &d2) ) return -1;
us1 = d1;
us2 = d2 - 1.0 + duts/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 * DAYSEC / ( DAYSEC + ddats );
/* Ramp UT1-UTC to bring about SOFA'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 / DAYSEC;
/* Result, safeguarding precision. */
if ( big1 ) {
*utc1 = u1;
*utc2 = u2;
} else {
*utc1 = u2;
*utc2 = u1;
}
/* Status. */
return js;
/*----------------------------------------------------------------------
**
** Copyright (C) 2017
** 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: [email protected]
** By post: IAU SOFA Center
** HM Nautical Almanac Office
** UK Hydrographic Office
** Admiralty Way, Taunton
** Somerset, TA1 2DN
** United Kingdom
**
**--------------------------------------------------------------------*/
}
