DateTime.hpp File Reference

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

#include <cmath>

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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)
	Integer divmod — matching legacy divMod().
bool	openswmm::datetime::isLeapYear (int year)
	Check if year is a leap year.
DateTime	openswmm::datetime::encodeDate (int year, int month, int day)
	Encode year-month-day to DateTime.
DateTime	openswmm::datetime::encodeTime (int hour, int minute, int second)
	Encode hour:minute:second to fractional day.
void	openswmm::datetime::decodeDate (DateTime date, int &year, int &month, int &day)
	Decode DateTime to year-month-day.
void	openswmm::datetime::decodeTime (DateTime time, int &h, int &m, int &s)
	Decode DateTime to hour:minute:second.
DateTime	openswmm::datetime::addSeconds (DateTime date, double seconds)
	Add seconds to a DateTime — numerically identical to legacy.
long	openswmm::datetime::timeDiff (DateTime date1, DateTime date2)
	Compute difference in seconds between two DateTimes.
int	openswmm::datetime::monthOfYear (DateTime date)
	Get month of year (1..12) from DateTime.
int	openswmm::datetime::dayOfYear (DateTime date)
	Get day of year (1..365/366) from DateTime.

Detailed Description

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

Replicates the exact date/time encoding, decoding, and arithmetic from the legacy SWMM datetime.c. Uses the same DateDelta epoch (days from 01/01/0000 to 12/31/1899), 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.

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

Copyright

Copyright (c) 2026 HydroCouple. All rights reserved.

License\n MIT License