DateTime utility functions — numerically identical to legacy datetime.c. More...

#include <cmath>

Include dependency graph for DateTime.hpp:

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Namespaces
namespace	openswmm

namespace	openswmm::datetime

Typedefs
using	openswmm::datetime::DateTime = double

Functions
void	openswmm::datetime::divMod (int n, int d, int result, int remainder)
	Divide integers with the legacy zero-divisor convention.

bool	openswmm::datetime::isLeapYear (int year)
	Test the proleptic Gregorian leap-year rule.

DateTime	openswmm::datetime::encodeDate (int year, int month, int day)
	Encode a Gregorian calendar date as midnight in SWMM days.

DateTime	openswmm::datetime::encodeTime (int hour, int minute, int second)
	Convert nonnegative time components to an elapsed-day fraction.

void	openswmm::datetime::decodeDate (DateTime date, int &year, int &month, int &day)
	Decode the whole-day part of a SWMM DateTime.

void	openswmm::datetime::decodeTime (DateTime time, int &h, int &m, int &s)
	Decode a SWMM day fraction to the nearest whole second.

DateTime	openswmm::datetime::addSeconds (DateTime date, double seconds)
	Add an offset after rounding the input time to whole seconds.

long	openswmm::datetime::timeDiff (DateTime date1, DateTime date2)
	Subtract two SWMM DateTimes using whole-second decoded times.

int	openswmm::datetime::monthOfYear (DateTime date)
	Extract the month from a SWMM DateTime.

int	openswmm::datetime::dayOfYear (DateTime date)
	Extract the ordinal day from a SWMM DateTime.

Detailed Description

DateTime utility functions — numerically identical to legacy datetime.c.

Uses the OLE Automation Date (OADate) / Delphi TDateTime convention: a double where the integer part is the number of days since December 30, 1899 and the fractional part represents time-of-day.

DateDelta = 693594 is the Gregorian ordinal of 1899-12-30 when 0001-01-01 is ordinal day 1. Subtracting it converts calendar ordinals to the SWMM epoch.

Replicates the exact date/time encoding, decoding, and arithmetic from the legacy SWMM datetime.c including the same integer H:M:S decomposition and the same rounding behavior.

This ensures that operations like datetime_addSeconds() produce bit-identical results to the legacy engine, which is critical for deterministic rain gage interval boundary alignment.

Note: This is NOT an astronomical Julian Date. SWMM uses the OADate convention throughout (matching Delphi's TDateTime type).

See also: Legacy reference: src/legacy/engine/datetime.c

Author: Caleb Buahin caleb.nosp@m..bua.nosp@m.hin@g.nosp@m.mail.nosp@m..com

License: Apache-2.0

Namespaces

Typedefs

Functions

Detailed Description