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#include "erfa.h"
#include <string.h>
int eraD2dtf(const char *scale, int ndp, double d1, double d2,
int *iy, int *im, int *id, int ihmsf[4])
/*
** - - - - - - - - -
** e r a 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).
**
** 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 ERFA 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 ERFA 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 eraDat for further details.
**
** 6) For calendar conventions and limitations, see eraCal2jd.
**
** Called:
** eraJd2cal JD to Gregorian calendar
** eraD2tf decompose days to hms
** eraDat delta(AT) = TAI-UTC
**
** Copyright (C) 2013-2014, NumFOCUS Foundation.
** Derived, with permission, from the SOFA library. See notes at end of file.
*/
{
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 = eraJd2cal(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 = eraDat(iy1, im1, id1, 0.0, &dat0);
if ( js < 0 ) return -1;
/* TAI-UTC at 12h today (to detect drift). */
js = eraDat(iy1, im1, id1, 0.5, &dat12);
if ( js < 0 ) return -1;
/* TAI-UTC at 0h tomorrow (to detect jumps). */
js = eraJd2cal(a1+1.5, b1-fd, &iy2, &im2, &id2, &w);
if ( js ) return -1;
js = eraDat(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 = (dleap != 0.0);
if (leap) fd += fd * dleap/ERFA_DAYSEC;
}
/* Provisional time of day. */
eraD2tf ( ndp, fd, &s, ihmsf1 );
/* Has the (rounded) time gone past 24h? */
if ( ihmsf1[0] > 23 ) {
/* Yes. We probably need tomorrow's calendar date. */
js = eraJd2cal(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;
}
/*----------------------------------------------------------------------
**
**
** Copyright (C) 2013-2014, 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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