Utility class that converts AceTime epoch days to (year, month, day) in the Gregorian calendar and vise versa. More...

#include <EpochConverterJulian.h>

Static Public Member Functions
static int32_t	toEpochDays (int16_t year, uint8_t month, uint8_t day)
	Convert (year, month, day) in the Gregorian calendar to days since the internal epoch (2000-01-01). More...

static void	fromEpochDays (int32_t epochDays, int16_t &year, uint8_t &month, uint8_t &day)
	Extract the (year, month, day) fields from AceTime epochDays. More...

Static Public Attributes
static const int16_t	kInternalEpochYear = 2000
	Epoch year used by this epoch converter. More...

static const int32_t	kDaysToInternalEpochFromUnixEpoch = 10957
	Number of days from Unix epoch (1970-01-01 00:00:00 UTC) to the internal epoch (2000-01-01 00:00:00 UTC).

static const int32_t	kDaysToInternalEpochFromJulianEpoch
	Number of days from the modified proleptic Julian calendar epoch (4713 BC 01-01, modified to start at 00:00:00 instead of 12:00:00) to the internal epoch (2000-01-01). More...

Detailed Description

Utility class that converts AceTime epoch days to (year, month, day) in the Gregorian calendar and vise versa.

Uses the algorithm described in https://en.wikipedia.org/wiki/Julian_day which converts into Julian days as an intermediate step.

Definition at line 19 of file EpochConverterJulian.h.

Member Function Documentation

◆ fromEpochDays()

static void ace_time::EpochConverterJulian::fromEpochDays	(	int32_t	epochDays,
		int16_t &	year,
		uint8_t &	month,
		uint8_t &	day
	)

inlinestatic

Extract the (year, month, day) fields from AceTime epochDays.

See https://en.wikipedia.org/wiki/Julian_day for formula.

No input validation is performed. The behavior is undefined if the parameters are outside their expected range.

Definition at line 86 of file EpochConverterJulian.h.

◆ toEpochDays()

static int32_t ace_time::EpochConverterJulian::toEpochDays	(	int16_t	year,
		uint8_t	month,
		uint8_t	day
	)

inlinestatic

Convert (year, month, day) in the Gregorian calendar to days since the internal epoch (2000-01-01).

The (year, month, day) is converted into Julian days, then converted to epoch days since AceTime Epoch. The Julian day normally start at 12:00:00, but we use a modified Julian day number starting at 00:00:00 to make it easier to convert to the Gregorian calendar day.

* JDN = (1461 x (Y + 4800 + (M - 14)/12))/4
*     + (367 x (M - 2 - 12 x ((M - 14)/12)))/12
*     - (3 x ((Y + 4900 + (M - 14)/12)/100))/4
*     + D - 32075
* JDN2000 = JDN - 2451545
*

It looks like the formula needs to be done using signed integers because it depends on the modulo operation (%) to truncate towards 0 for negative numbers.

No input validation is performed. The behavior is undefined if the parameters are outside their expected range.

Parameters

year	year [1,9999]
month	month integer [1, 12]
day	day of month integer[1, 31]

Definition at line 70 of file EpochConverterJulian.h.

Member Data Documentation

◆ kDaysToInternalEpochFromJulianEpoch

const int32_t ace_time::EpochConverterJulian::kDaysToInternalEpochFromJulianEpoch

static

Initial value:

= 1721060

+ (kInternalEpochYear / 400) * 146097

ace_time::EpochConverterJulian::kInternalEpochYear

static const int16_t kInternalEpochYear

Epoch year used by this epoch converter.

Definition: EpochConverterJulian.h:25

Number of days from the modified proleptic Julian calendar epoch (4713 BC 01-01, modified to start at 00:00:00 instead of 12:00:00) to the internal epoch (2000-01-01).

There are 1721060 days from the modified Julian epoch to 0000-01-01 of the proleptic Gregorian calendar. We then need to add 2000 years (5 x 400 years) to get to 2000-01-01.

Definition at line 40 of file EpochConverterJulian.h.

◆ kInternalEpochYear

const int16_t ace_time::EpochConverterJulian::kInternalEpochYear = 2000

static

Epoch year used by this epoch converter.

Must be a multiple of 400. Other parts of the AceTime library will probably use a different epoch year.

Definition at line 25 of file EpochConverterJulian.h.

The documentation for this class was generated from the following file:

/home/brian/src/AceTimeSuite/libraries/AceTimeLib/src/ace_time/EpochConverterJulian.h

Static Public Member Functions