testbed/astropy__astropy/cextern/erfa/a2tf.c

#include "erfa.h"

void eraA2tf(int ndp, double angle, char *sign, int ihmsf[4])
/*
**  - - - - - - - -
**   e r a A 2 t f
**  - - - - - - - -
**
**  Decompose radians into hours, minutes, seconds, fraction.
**
**  Given:
**     ndp     int     resolution (Note 1)
**     angle   double  angle in radians
**
**  Returned:
**     sign    char    '+' or '-'
**     ihmsf   int[4]  hours, minutes, seconds, fraction
**
**  Called:
**     eraD2tf      decompose days to hms
**
**  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 angle, the format of doubles on the target platform, and
**     the risk of overflowing ihmsf[3].  On a typical platform, for
**     angle up to 2pi, 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 angle may exceed 2pi.  In cases where it
**     does not, it is up to the caller to test for and handle the
**     case where angle is very nearly 2pi and rounds up to 24 hours,
**     by testing for ihmsf[0]=24 and setting ihmsf[0-3] to zero.
**
**  Copyright (C) 2013-2017, NumFOCUS Foundation.
**  Derived, with permission, from the SOFA library.  See notes at end of file.
*/
{
/* Scale then use days to h,m,s function. */
   eraD2tf(ndp, angle/ERFA_D2PI, sign, ihmsf);

   return;

}
/*----------------------------------------------------------------------
**  
**  
**  Copyright (C) 2013-2017, 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
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**  FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
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*/