yodaUtility/sgp4/cJulian.h

//
// cJulian.h
//
// Copyright (c) 2003 Michael F. Henry
//
#pragma once
#include "globals.h"
#include <time.h>

//
// See note in cJulian.cpp for information on this class and the epoch dates
//
const double EPOCH_JAN1_00H_1900 = 2415019.5; // Jan 1.0 1900 = Jan 1 1900 00h UTC
const double EPOCH_JAN1_12H_1900 = 2415020.0; // Jan 1.5 1900 = Jan 1 1900 12h UTC
const double EPOCH_JAN1_12H_2000 = 2451545.0; // Jan 1.5 2000 = Jan 1 2000 12h UTC

//////////////////////////////////////////////////////////////////////////////
class cJulian  
{
public:
   cJulian() { Initialize(2000, 1); }
   explicit cJulian(time_t t);              // Create from time_t
   explicit cJulian(int year, double day);  // Create from year, day of year
   explicit cJulian(int year,               // i.e., 2004
                    int mon,                // 1..12
                    int day,                // 1..31
                    int hour,               // 0..23
                    int min,                // 0..59
                    double sec = 0.0);      // 0..(59.999999...)
   ~cJulian() {};

   double toGMST() const;           // Greenwich Mean Sidereal Time
   double toLMST(double lon) const; // Local Mean Sideral Time
   time_t toTime() const;           // To time_t type - avoid using

   double FromJan1_00h_1900() const { return m_Date - EPOCH_JAN1_00H_1900; }
   double FromJan1_12h_1900() const { return m_Date - EPOCH_JAN1_12H_1900; }
   double FromJan1_12h_2000() const { return m_Date - EPOCH_JAN1_12H_2000; }

   void getComponent(int *pYear, int *pMon = NULL, double *pDOM = NULL) const;
   double getDate() const { return m_Date; }

   void addDay (double day) { m_Date += day;                 }
   void addHour(double hr ) { m_Date += (hr  / HR_PER_DAY ); }
   void addMin (double min) { m_Date += (min / MIN_PER_DAY); }
   void addSec (double sec) { m_Date += (sec / SEC_PER_DAY); }

   double spanDay (const cJulian& b) const { return m_Date - b.m_Date;        }
   double spanHour(const cJulian& b) const { return spanDay(b) * HR_PER_DAY;  }
   double spanMin (const cJulian& b) const { return spanDay(b) * MIN_PER_DAY; }
   double spanSec (const cJulian& b) const { return spanDay(b) * SEC_PER_DAY; }

   static bool IsLeapYear(int y)
      { return (y % 4 == 0 && y % 100 != 0) || (y % 400 == 0); }

protected:
   void Initialize(int year, double day);

   double m_Date; // Julian date
};
1	//
2	// cJulian.h
3	//
4	// Copyright (c) 2003 Michael F. Henry
5	//
6	#pragma once
7	#include "globals.h"
8	#include <time.h>
9
10	//
11	// See note in cJulian.cpp for information on this class and the epoch dates
12	//
13	const double EPOCH_JAN1_00H_1900 = 2415019.5; // Jan 1.0 1900 = Jan 1 1900 00h UTC
14	const double EPOCH_JAN1_12H_1900 = 2415020.0; // Jan 1.5 1900 = Jan 1 1900 12h UTC
15	const double EPOCH_JAN1_12H_2000 = 2451545.0; // Jan 1.5 2000 = Jan 1 2000 12h UTC
16
17	//////////////////////////////////////////////////////////////////////////////
18	class cJulian
19	{
20	public:
21	cJulian() { Initialize(2000, 1); }
22	explicit cJulian(time_t t); // Create from time_t
23	explicit cJulian(int year, double day); // Create from year, day of year
24	explicit cJulian(int year, // i.e., 2004
25	int mon, // 1..12
26	int day, // 1..31
27	int hour, // 0..23
28	int min, // 0..59
29	double sec = 0.0); // 0..(59.999999...)
30	~cJulian() {};
31
32	double toGMST() const; // Greenwich Mean Sidereal Time
33	double toLMST(double lon) const; // Local Mean Sideral Time
34	time_t toTime() const; // To time_t type - avoid using
35
36	double FromJan1_00h_1900() const { return m_Date - EPOCH_JAN1_00H_1900; }
37	double FromJan1_12h_1900() const { return m_Date - EPOCH_JAN1_12H_1900; }
38	double FromJan1_12h_2000() const { return m_Date - EPOCH_JAN1_12H_2000; }
39
40	void getComponent(int pYear, int pMon = NULL, double *pDOM = NULL) const;
41	double getDate() const { return m_Date; }
42
43	void addDay (double day) { m_Date += day; }
44	void addHour(double hr ) { m_Date += (hr / HR_PER_DAY ); }
45	void addMin (double min) { m_Date += (min / MIN_PER_DAY); }
46	void addSec (double sec) { m_Date += (sec / SEC_PER_DAY); }
47
48	double spanDay (const cJulian& b) const { return m_Date - b.m_Date; }
49	double spanHour(const cJulian& b) const { return spanDay(b) * HR_PER_DAY; }
50	double spanMin (const cJulian& b) const { return spanDay(b) * MIN_PER_DAY; }
51	double spanSec (const cJulian& b) const { return spanDay(b) * SEC_PER_DAY; }
52
53	static bool IsLeapYear(int y)
54	{ return (y % 4 == 0 && y % 100 != 0) \|\| (y % 400 == 0); }
55
56	protected:
57	void Initialize(int year, double day);
58
59	double m_Date; // Julian date
60	};