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#include "erfa.h"
void eraD2tf(int ndp, double days, char *sign, int ihmsf[4])
/*
** - - - - - - - -
** e r a D 2 t f
** - - - - - - - -
**
** Decompose days to hours, minutes, seconds, fraction.
**
** Given:
** ndp int resolution (Note 1)
** days double interval in days
**
** Returned:
** sign char '+' or '-'
** ihmsf int[4] hours, minutes, seconds, fraction
**
** Notes:
**
** 1) The argument ndp is interpreted as follows:
**
** ndp resolution
** : ...0000 00 00
** -7 1000 00 00
** -6 100 00 00
** -5 10 00 00
** -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
** : 0 00 00.000...
**
** 2) The largest positive useful value for ndp is determined by the
** size of days, the format of double on the target platform, and
** the risk of overflowing ihmsf[3]. On a typical platform, for
** days up to 1.0, the available floating-point precision might
** correspond to ndp=12. However, the practical limit is typically
** ndp=9, set by the capacity of a 32-bit int, or ndp=4 if int is
** only 16 bits.
**
** 3) The absolute value of days may exceed 1.0. In cases where it
** does not, it is up to the caller to test for and handle the
** case where days is very nearly 1.0 and rounds up to 24 hours,
** by testing for ihmsf[0]=24 and setting ihmsf[0-3] to zero.
**
** Copyright (C) 2013-2014, NumFOCUS Foundation.
** Derived, with permission, from the SOFA library. See notes at end of file.
*/
{
int nrs, n;
double rs, rm, rh, a, w, ah, am, as, af;
/* Handle sign. */
*sign = (char) ( ( days >= 0.0 ) ? '+' : '-' );
/* Interval in seconds. */
a = ERFA_DAYSEC * fabs(days);
/* Pre-round if resolution coarser than 1s (then pretend ndp=1). */
if (ndp < 0) {
nrs = 1;
for (n = 1; n <= -ndp; n++) {
nrs *= (n == 2 || n == 4) ? 6 : 10;
}
rs = (double) nrs;
w = a / rs;
a = rs * ERFA_DNINT(w);
}
/* Express the unit of each field in resolution units. */
nrs = 1;
for (n = 1; n <= ndp; n++) {
nrs *= 10;
}
rs = (double) nrs;
rm = rs * 60.0;
rh = rm * 60.0;
/* Round the interval and express in resolution units. */
a = ERFA_DNINT(rs * a);
/* Break into fields. */
ah = a / rh;
ah = ERFA_DINT(ah);
a -= ah * rh;
am = a / rm;
am = ERFA_DINT(am);
a -= am * rm;
as = a / rs;
as = ERFA_DINT(as);
af = a - as * rs;
/* Return results. */
ihmsf[0] = (int) ah;
ihmsf[1] = (int) am;
ihmsf[2] = (int) as;
ihmsf[3] = (int) af;
return;
}
/*----------------------------------------------------------------------
**
**
** 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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