Find file
18ce15b Jul 6, 2016
145 lines (120 sloc) 6.4 KB
time.h - low level time and date functions
July 3 2011 - fixed elapsedSecsThisWeek macro (thanks Vincent Valdy for this)
- fixed daysToTime_t macro (thanks maniacbug)
#ifndef _Time_h
#ifdef __cplusplus
#define _Time_h
#include <inttypes.h>
#ifndef __AVR__
#include <sys/types.h> // for __time_t_defined, but avr libc lacks sys/types.h
#if !defined(__time_t_defined) // avoid conflict with newlib or other posix libc
typedef unsigned long time_t;
// This ugly hack allows us to define C++ overloaded functions, when included
// from within an extern "C", as newlib's sys/stat.h does. Actually it is
// intended to include "time.h" from the C library (on ARM, but AVR does not
// have that file at all). On Mac and Windows, the compiler will find this
// "Time.h" instead of the C library "time.h", so we may cause other weird
// and unpredictable effects by conflicting with the C library header "time.h",
// but at least this hack lets us define C++ functions as intended. Hopefully
// nothing too terrible will result from overriding the C library header?!
extern "C++" {
typedef enum {timeNotSet, timeNeedsSync, timeSet
} timeStatus_t ;
typedef enum {
dowInvalid, dowSunday, dowMonday, dowTuesday, dowWednesday, dowThursday, dowFriday, dowSaturday
} timeDayOfWeek_t;
typedef enum {
tmSecond, tmMinute, tmHour, tmWday, tmDay,tmMonth, tmYear, tmNbrFields
} tmByteFields;
typedef struct {
uint8_t Second;
uint8_t Minute;
uint8_t Hour;
uint8_t Wday; // day of week, sunday is day 1
uint8_t Day;
uint8_t Month;
uint8_t Year; // offset from 1970;
} tmElements_t, TimeElements, *tmElementsPtr_t;
//convenience macros to convert to and from tm years
#define tmYearToCalendar(Y) ((Y) + 1970) // full four digit year
#define CalendarYrToTm(Y) ((Y) - 1970)
#define tmYearToY2k(Y) ((Y) - 30) // offset is from 2000
#define y2kYearToTm(Y) ((Y) + 30)
typedef time_t(*getExternalTime)();
//typedef void (*setExternalTime)(const time_t); // not used in this version
/* Useful Constants */
#define SECS_PER_MIN ((time_t)(60UL))
#define SECS_PER_HOUR ((time_t)(3600UL))
#define SECS_PER_DAY ((time_t)(SECS_PER_HOUR * 24UL))
#define DAYS_PER_WEEK ((time_t)(7UL))
#define SECS_PER_YEAR ((time_t)(SECS_PER_WEEK * 52UL))
#define SECS_YR_2000 ((time_t)(946684800UL)) // the time at the start of y2k
/* Useful Macros for getting elapsed time */
#define numberOfSeconds(_time_) (_time_ % SECS_PER_MIN)
#define numberOfMinutes(_time_) ((_time_ / SECS_PER_MIN) % SECS_PER_MIN)
#define numberOfHours(_time_) (( _time_% SECS_PER_DAY) / SECS_PER_HOUR)
#define dayOfWeek(_time_) ((( _time_ / SECS_PER_DAY + 4) % DAYS_PER_WEEK)+1) // 1 = Sunday
#define elapsedDays(_time_) ( _time_ / SECS_PER_DAY) // this is number of days since Jan 1 1970
#define elapsedSecsToday(_time_) (_time_ % SECS_PER_DAY) // the number of seconds since last midnight
// The following macros are used in calculating alarms and assume the clock is set to a date later than Jan 1 1971
// Always set the correct time before settting alarms
#define previousMidnight(_time_) (( _time_ / SECS_PER_DAY) * SECS_PER_DAY) // time at the start of the given day
#define nextMidnight(_time_) ( previousMidnight(_time_) + SECS_PER_DAY ) // time at the end of the given day
#define elapsedSecsThisWeek(_time_) (elapsedSecsToday(_time_) + ((dayOfWeek(_time_)-1) * SECS_PER_DAY) ) // note that week starts on day 1
#define previousSunday(_time_) (_time_ - elapsedSecsThisWeek(_time_)) // time at the start of the week for the given time
#define nextSunday(_time_) ( previousSunday(_time_)+SECS_PER_WEEK) // time at the end of the week for the given time
/* Useful Macros for converting elapsed time to a time_t */
#define minutesToTime_t ((M)) ( (M) * SECS_PER_MIN)
#define hoursToTime_t ((H)) ( (H) * SECS_PER_HOUR)
#define daysToTime_t ((D)) ( (D) * SECS_PER_DAY) // fixed on Jul 22 2011
#define weeksToTime_t ((W)) ( (W) * SECS_PER_WEEK)
/* time and date functions */
int hour(); // the hour now
int hour(time_t t); // the hour for the given time
int hourFormat12(); // the hour now in 12 hour format
int hourFormat12(time_t t); // the hour for the given time in 12 hour format
uint8_t isAM(); // returns true if time now is AM
uint8_t isAM(time_t t); // returns true the given time is AM
uint8_t isPM(); // returns true if time now is PM
uint8_t isPM(time_t t); // returns true the given time is PM
int minute(); // the minute now
int minute(time_t t); // the minute for the given time
int second(); // the second now
int second(time_t t); // the second for the given time
int day(); // the day now
int day(time_t t); // the day for the given time
int weekday(); // the weekday now (Sunday is day 1)
int weekday(time_t t); // the weekday for the given time
int month(); // the month now (Jan is month 1)
int month(time_t t); // the month for the given time
int year(); // the full four digit year: (2009, 2010 etc)
int year(time_t t); // the year for the given time
time_t now(); // return the current time as seconds since Jan 1 1970
void setTime(time_t t);
void setTime(int hr,int min,int sec,int day, int month, int yr);
void adjustTime(long adjustment);
/* date strings */
#define dt_MAX_STRING_LEN 9 // length of longest date string (excluding terminating null)
char* monthStr(uint8_t month);
char* dayStr(uint8_t day);
char* monthShortStr(uint8_t month);
char* dayShortStr(uint8_t day);
/* time sync functions */
timeStatus_t timeStatus(); // indicates if time has been set and recently synchronized
void setSyncProvider( getExternalTime getTimeFunction); // identify the external time provider
void setSyncInterval(time_t interval); // set the number of seconds between re-sync
/* low level functions to convert to and from system time */
void breakTime(time_t time, tmElements_t &tm); // break time_t into elements
time_t makeTime(tmElements_t &tm); // convert time elements into time_t
} // extern "C++"
#endif // __cplusplus
#endif /* _Time_h */