#include "sofa.h" #include "sofam.h" #include int iauD2dtf(const char *scale, int ndp, double d1, double d2, int *iy, int *im, int *id, int ihmsf[4]) /* ** - - - - - - - - - ** i a u D 2 d t f ** - - - - - - - - - ** ** Format for output a 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) ** ndp int resolution (Note 2) ** d1,d2 double time as a 2-part Julian Date (Notes 3,4) ** ** Returned: ** iy,im,id int year, month, day in Gregorian calendar (Note 5) ** ihmsf int[4] hours, minutes, seconds, fraction (Note 1) ** ** Returned (function value): ** int status: +1 = dubious year (Note 5) ** 0 = OK ** -1 = unacceptable date (Note 6) ** ** 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) ndp is the number of decimal places in the seconds field, and can ** have negative as well as positive values, such as: ** ** ndp resolution ** -4 1 00 00 ** -3 0 10 00 ** -2 0 01 00 ** -1 0 00 10 ** 0 0 00 01 ** 1 0 00 00.1 ** 2 0 00 00.01 ** 3 0 00 00.001 ** ** The limits are platform dependent, but a safe range is -5 to +9. ** ** 3) d1+d2 is Julian Date, apportioned in any convenient way between ** the two arguments, for example where 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 "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. ** ** 6) For calendar conventions and limitations, see iauCal2jd. ** ** Called: ** iauJd2cal JD to Gregorian calendar ** iauD2tf decompose days to hms ** iauDat delta(AT) = TAI-UTC ** ** This revision: 2021 May 11 ** ** SOFA release 2021-05-12 ** ** Copyright (C) 2021 IAU SOFA Board. See notes at end. */ { int leap; char s; int iy1, im1, id1, js, iy2, im2, id2, ihmsf1[4], i; double a1, b1, fd, dat0, dat12, w, dat24, dleap; /* The two-part JD. */ a1 = d1; b1 = d2; /* Provisional calendar date. */ js = iauJd2cal(a1, b1, &iy1, &im1, &id1, &fd); if ( js ) return -1; /* Is this a leap second day? */ leap = 0; if ( ! strcmp(scale,"UTC") ) { /* TAI-UTC at 0h today. */ js = iauDat(iy1, im1, id1, 0.0, &dat0); if ( js < 0 ) return -1; /* TAI-UTC at 12h today (to detect drift). */ js = iauDat(iy1, im1, id1, 0.5, &dat12); if ( js < 0 ) return -1; /* TAI-UTC at 0h tomorrow (to detect jumps). */ js = iauJd2cal(a1+1.5, b1-fd, &iy2, &im2, &id2, &w); if ( js ) return -1; js = iauDat(iy2, im2, id2, 0.0, &dat24); if ( js < 0 ) return -1; /* Any sudden change in TAI-UTC (seconds). */ dleap = dat24 - (2.0*dat12 - dat0); /* If leap second day, scale the fraction of a day into SI. */ leap = (fabs(dleap) > 0.5); if (leap) fd += fd * dleap/DAYSEC; } /* Provisional time of day. */ iauD2tf ( ndp, fd, &s, ihmsf1 ); /* Has the (rounded) time gone past 24h? */ if ( ihmsf1[0] > 23 ) { /* Yes. We probably need tomorrow's calendar date. */ js = iauJd2cal(a1+1.5, b1-fd, &iy2, &im2, &id2, &w); if ( js ) return -1; /* Is today a leap second day? */ if ( ! leap ) { /* No. Use 0h tomorrow. */ iy1 = iy2; im1 = im2; id1 = id2; ihmsf1[0] = 0; ihmsf1[1] = 0; ihmsf1[2] = 0; } else { /* Yes. Are we past the leap second itself? */ if ( ihmsf1[2] > 0 ) { /* Yes. Use tomorrow but allow for the leap second. */ iy1 = iy2; im1 = im2; id1 = id2; ihmsf1[0] = 0; ihmsf1[1] = 0; ihmsf1[2] = 0; } else { /* No. Use 23 59 60... today. */ ihmsf1[0] = 23; ihmsf1[1] = 59; ihmsf1[2] = 60; } /* If rounding to 10s or coarser always go up to new day. */ if ( ndp < 0 && ihmsf1[2] == 60 ) { iy1 = iy2; im1 = im2; id1 = id2; ihmsf1[0] = 0; ihmsf1[1] = 0; ihmsf1[2] = 0; } } } /* Results. */ *iy = iy1; *im = im1; *id = id1; for ( i = 0; i < 4; i++ ) { ihmsf[i] = ihmsf1[i]; } /* Status. */ return js; /* Finished. */ /*---------------------------------------------------------------------- ** ** Copyright (C) 2021 ** 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 ** **--------------------------------------------------------------------*/ }