include/slib/timedate.h

   1 /*
   2  *  timedate.h - Time and date operations of the slib
   3  *
   4  *  Copyright (C) 2018-2020 Zhang Maiyun
   5  *
   6  *  This file is part of the slib.
   7  *  The slib is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU Lesser General Public License as published by
   9  *  the Free Software Foundation; either version 3 of the License, or
  10  *  (at your option) any later version.
  11  *
  12  *  This program is distributed in the hope that it will be useful,
  13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *  GNU Lesser General Public License for more details.
  16  *
  17  *  You should have received a copy of the GNU Lesser General Public License
  18  *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
  19  */
  20
  21 #ifndef SLIB_TIMEDATE_H
  22 #define SLIB_TIMEDATE_H 1
  23
  24 #include "slib/general.h"
  25
  26 /* leap year: every four years before 1582 or exclude non-four-hundredth if it's
  27  * a centennial year */
  28 /* leap year here: proleptic */
  29 #define isleap(year) (year % 400 == 0 || (year % 4 == 0 && year % 100 != 0))
  30
  31 _BEGIN_EXTERN_C
  32
  33 OPT void slib_h2hms(double in_hours, double *out_hours, double *out_minutes,
  34                     double *out_seconds);
  35
  36 OPT double slib_hms2h(double hours, double minutes, double seconds);
  37
  38 OPT int slib_d2dn(int year, int month, int day);
  39
  40 OPT double slib_true_time_diff(double longitude);
  41
  42 OPT double slib_local_time(double longitude, double hours, double timezone);
  43
  44 OPT double slib_tm2jd(struct tm *tm);
  45
  46 OPT void slib_jd2tm(double jd, struct tm *tm);
  47
  48 _END_EXTERN_C
  49 #endif