julian-date.h

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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2016 INESC TEC
 * Copyright (c) 2021 CNES
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation;
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Code from https://gitlab.inesctec.pt/pmms/ns3-satellite
 *
 * Author: Pedro Silva  <pmms@inesctec.pt>
 * Author: Bastien Tauran <bastien.tauran@viveris.fr>
 */
 
#ifndef JULIANDATE_H
#define JULIANDATE_H
 
#include "ns3/nstime.h"
 
#include <functional>
#include <ostream>
#include <stdint.h>
#include <string>
#include <utility>
 
namespace ns3
{

struct DateTime
{
    enum TimeSystem
    {
        UTC,  
        UT1,  
        TAI,  
        TT,   
        GPST, 
        POSIX 
    };
 
    uint32_t year, month, day;
    uint32_t hours, minutes, seconds, millisecs;
    TimeSystem time_system;
 
    friend std::ostream& operator<<(std::ostream& os, DateTime::TimeSystem ts);
};

class JulianDate
{
    typedef DateTime::TimeSystem TimeSystem;
 
  public:
    static const uint32_t PosixYear;  
    static const uint32_t MinYear;    
    static const uint32_t MaxYear;    
    static const double PosixEpoch;   
    static const uint32_t J2000Epoch; 
    static const uint32_t Posix1992;  
    static const uint32_t HourToMs;   
    static const uint32_t DayToMs;    
    static const Time TtToTai;        
    static const Time TaiToGps;       

    JulianDate(void);

    JulianDate(double jd);

    JulianDate(uint32_t days, uint32_t ms_day);

    JulianDate(const std::string& date, TimeSystem ts = DateTime::UTC);

    double GetDouble(TimeSystem ts = DateTime::UTC) const;

    DateTime GetDateTime(void) const;

    DateTime GetDateTime(TimeSystem ts) const;

    std::string ToString(void) const;

    std::string ToString(TimeSystem ts) const;

    std::pair<double, double> GetPolarMotion(void) const;

    double GetOmegaEarth(void) const;

    double GetGmst(void) const;

    void SetDate(double jd);

    void SetDate(uint32_t days, uint32_t ms_day);

    void SetDate(const std::string& date, TimeSystem ts = DateTime::UTC);

    JulianDate operator+(const Time& t) const;

    void operator+=(const Time& t);

    JulianDate operator-(const Time& t) const;

    void operator-=(const Time& t);

    Time operator-(const JulianDate& jd) const;

    bool operator<(const JulianDate& jd) const;

    bool operator<=(const JulianDate& jd) const;

    bool operator>(const JulianDate& jd) const;

    bool operator>=(const JulianDate& jd) const;

    bool operator==(const JulianDate& jd) const;

    bool operator!=(const JulianDate& jd) const;

    friend std::ostream& operator<<(std::ostream& os, const JulianDate& jd);
 
  private:
    static bool IsLeapYear(uint32_t year);

    static Time TaiMinusUtc(uint32_t daysInPosix);

    static Time Dut1(uint32_t daysInPosix);

    static DateTime GregorianDate(uint32_t days, uint32_t ms_day);

    static Time OffsetFromUtc(uint32_t daysInPosix, TimeSystem ts);

    static Time OffsetToUtc(uint32_t daysInPosix, uint32_t ms_day, TimeSystem ts);

    DateTime GregorianDate(void) const;

    Time OffsetFromUtc(void) const;

    Time OffsetToUtc(void) const;
 
    uint32_t m_days;         
    uint32_t m_ms_day;       
    TimeSystem m_time_scale; 
};
 
} // namespace ns3
 
#endif /* JULIANDATE_H */