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class TTimeStamp


 The TTimeStamp encapsulates seconds and ns since EPOCH

 This extends (and isolates) struct timespec
    struct timespec
       {
          time_t   tv_sec;   /* seconds *
          long     tv_nsec;  /* nanoseconds *
       }
    time_t seconds is relative to Jan 1, 1970 00:00:00 UTC

 No accounting of leap seconds is made.

 Due to ROOT/CINT limitations TTimeStamp does not explicitly
 hold a timespec struct; attempting to do so means the Streamer
 must be hand written.  Instead we have chosen to simply contain
 similar fields within the private area of this class.

 NOTE: the use of time_t (and its default implementation as a 32 int)
       implies overflow conditions occurs somewhere around
       Jan 18, 19:14:07, 2038.
       If this experiment is still going when it becomes significant
       someone will have to deal with it.


Function Members (Methods)

public:
TTimeStamp()
TTimeStamp(const timespec_t& ts)
TTimeStamp(const TTimeStamp&)
TTimeStamp(time_t t, Int_t nsec)
TTimeStamp(UInt_t tloc, Bool_t isUTC = kTRUE, Int_t secOffset = 0, Bool_t dosDate = kFALSE)
TTimeStamp(UInt_t date, UInt_t time, UInt_t nsec, Bool_t isUTC = kTRUE, Int_t secOffset = 0)
TTimeStamp(UInt_t year, UInt_t month, UInt_t day, UInt_t hour, UInt_t min, UInt_t sec, UInt_t nsec = 0, Bool_t isUTC = kTRUE, Int_t secOffset = 0)
virtual~TTimeStamp()
voidAdd(const TTimeStamp& offset)
Double_tAsDouble() const
Double_tAsGAST(Double_t UT1Offset = 0) const
Double_tAsGMST(Double_t UT1Offset = 0) const
Double_tAsJulianDate() const
Double_tAsLAST(Double_t Longitude, Double_t UT1Offset = 0) const
Double_tAsLMST(Double_t Longitude, Double_t UT1Offset = 0) const
const char*AsString(Option_t* option = "") const
static TClass*Class()
voidCopy(TTimeStamp& ts) const
static voidDumpTMStruct(const tm_t& tmstruct)
UInt_tGetDate(Bool_t inUTC = kTRUE, Int_t secOffset = 0, UInt_t* year = 0, UInt_t* month = 0, UInt_t* day = 0) const
Int_tGetDayOfWeek(Bool_t inUTC = kTRUE, Int_t secOffset = 0) const
static Int_tGetDayOfWeek(Int_t day, Int_t month, Int_t year)
Int_tGetDayOfYear(Bool_t inUTC = kTRUE, Int_t secOffset = 0) const
static Int_tGetDayOfYear(Int_t day, Int_t month, Int_t year)
Int_tGetMonth(Bool_t inUTC = kTRUE, Int_t secOffset = 0) const
Int_tGetNanoSec() const
time_tGetSec() const
UInt_tGetTime(Bool_t inUTC = kTRUE, Int_t secOffset = 0, UInt_t* hour = 0, UInt_t* min = 0, UInt_t* sec = 0) const
timespec_tGetTimeSpec() const
Int_tGetWeek(Bool_t inUTC = kTRUE, Int_t secOffset = 0) const
static Int_tGetWeek(Int_t day, Int_t month, Int_t year)
static Int_tGetZoneOffset()
virtual TClass*IsA() const
static Bool_tIsLeapYear(Int_t year)
Bool_tIsLeapYear(Bool_t inUTC = kTRUE, Int_t secOffset = 0) const
static time_tMktimeFromUTC(tm_t* tmstruct)
doubleoperator double() const
TTimeStamp&operator=(const TTimeStamp&)
voidPrint(Option_t* option = "") const
voidSet()
voidSet(UInt_t tloc, Bool_t isUTC, Int_t secOffset, Bool_t dosDate)
voidSet(Int_t date, Int_t time, Int_t nsec, Bool_t isUTC, Int_t secOffset)
voidSet(Int_t year, Int_t month, Int_t day, Int_t hour, Int_t min, Int_t sec, Int_t nsec, Bool_t isUTC, Int_t secOffset)
voidSetNanoSec(Int_t nsec)
voidSetSec(Int_t sec)
virtual voidShowMembers(TMemberInspector&)
virtual voidStreamer(TBuffer&)
voidStreamerNVirtual(TBuffer& ClassDef_StreamerNVirtual_b)
private:
voidNormalizeNanoSec()

Data Members

private:
Int_tfNanoSecnanoseconds
Int_tfSecseconds

Class Charts

Inheritance Inherited Members Includes Libraries
Class Charts

Function documentation

TTimeStamp()
 Default ctor. Create a TTimeStamp and set it to the current time
 (as best possible). The nanosecond part is faked so that subsequenct
 calls simply add 1 to ensure that sequential calls are distinct
 (and sortable).
TTimeStamp(UInt_t year, UInt_t month, UInt_t day, UInt_t hour, UInt_t min, UInt_t sec, UInt_t nsec = 0, Bool_t isUTC = kTRUE, Int_t secOffset = 0)
 Create a TTimeStamp and set it to the specified year, month,
 day, time, hour, minute, second and nanosec.
 If !isUTC then it is assumed to be the standard local time zone.

 If local time is PST then one can use
    TTimeStamp(year,month,day,hour,min,sec,nsec,kFALSE,0);
 or
    Int_t secOffset = 8*60*60;
    TTimeStamp(year,month,day,hour,min,sec,nsec,kTRUE,8*60*60);
TTimeStamp(UInt_t date, UInt_t time, UInt_t nsec, Bool_t isUTC = kTRUE, Int_t secOffset = 0)
 Create a TTimeStamp and set it to the specified date, time, nanosec.
 If !isUTC then it is assumed to be the standard local time zone.
TTimeStamp(UInt_t tloc, Bool_t isUTC = kTRUE, Int_t secOffset = 0, Bool_t dosDate = kFALSE)
 Create a TTimeStamp and set it to tloc which must be a time_t value
 returned by time(). This value is the number of seconds since the EPOCH
 (i.e. 00:00:00 on Jan 1m 1970). If dosDate is true then the input
 is a dosDate value.
Double_t AsGMST(Double_t UT1Offset = 0) const
 Return Greenwich mean sidereal time (GMST) in hour-angle. Return value
 will always be between 0 and 24 (hours). Sidereal time is most accurately
 calculated from UT1. If fSec and fNanoSec are in UTC (which they are by
 default), the optional argument UT1Offset can be supplied (in
 milliseconds). If UT1Offset is not supplied, conversion has maximum error
 of 1s. If offset is supplied error can be reduced to us level. Values for
 UT1Offset can be found in IERS Bulletin B:
 ftp://ftp.iers.org/products/eop/bulletinb/format_2009
 The conversion to sidereal time used here is given by
 Aoki et. al. Astron. Astrophys. 105, 359-362 (1982)
 http://adsabs.harvard.edu/abs/1982A%26A...105..359A
Double_t AsGAST(Double_t UT1Offset = 0) const
 Return Greenwich apparant sidereal time (GAST) in hour-angle. Return
 value will always be between 0 and 24 (hours). Sidereal time is most
 accurately calculated from UT1. If fSec and fNanoSec are in UTC (which
 they are by default), the optional argument UT1Offset can be supplied (in
 milliseconds). If UT1Offset is not supplied, conversion has maximum error
 of 1s. If offset is supplied error can be reduced to us level. Values for
 UT1Offset can be found in IERS Bulletin B:
 ftp://ftp.iers.org/products/eop/bulletinb/format_2009
 Equation of the equinoxes is given by USNO:
 http://aa.usno.navy.mil/faq/docs/GAST.php
Double_t AsLMST(Double_t Longitude, Double_t UT1Offset = 0) const
 Return local mean sidereal time (LMST) in hour-angle, given a longitude
 in degrees. Return value will always be between 0 and 24 (hours).
 Sidereal time is most accurately calculated from UT1. If fSec and
 fNanoSec are in UTC (which they are by default), the optional argument
 UT1Offset can be supplied (in milliseconds). If UT1Offset is not
 supplied, conversion has maximum error of 1s. If offset is supplied error
 can be reduced to us level. Values for UT1Offset can be found in IERS
 Bulletin B: ftp://ftp.iers.org/products/eop/bulletinb/format_2009
Double_t AsLAST(Double_t Longitude, Double_t UT1Offset = 0) const
 Return local apparant sidereal time (LAST) in hour-angle, given a
 longitude in degrees. Return value will always be between 0 and 24
 (hours). Sidereal time is most accurately calculated from UT1. If fSec
 and fNanoSec are in UTC (which they are by default), the optional
 argument UT1Offset can be supplied (in milliseconds). If UT1Offset is not
 supplied, conversion has maximum error of 1s. If offset is supplied error
 can be reduced to us level. Values for UT1Offset can be found in IERS
 Bulletin B: ftp://ftp.iers.org/products/eop/bulletinb/format_2009
const Char_t * AsString(Option_t* option = "") const
 Return the date & time as a string.

 Result is pointer to a statically allocated string.
 User should copy this into their own buffer before calling
 this method again.

 Option "l" returns it in local zone format
 (can be applied to default or compact format).

 Default format is RFC822 compliant:
   "Mon, 02 Jan 2001 18:11:12 +0000 (GMT) +999999999 nsec"
   "Mon, 02 Jan 2001 10:11:12 -0800 (PST) +999999999 nsec"

 Option "c" compact is (almost) ISO 8601 compliant:
   "2001-01-02 18:11:12.9999999999Z"
   "2001-01-02 10:11:12.9999999999-0800"  if PST
      * uses "-" as date separator as specified in ISO 8601
      * uses "." rather than preferred "," for decimal separator
      * -HHMM is the difference between local and UTC (if behind, + if ahead).
   The "-HHMM" is replaced with "Z" if given as UTC.
   To be strictly conforming it should use "T" instead of the
   blank separating the date and time.

 Option "2" returns as {sec,nsec} integers.

 Option "s" returns "2001-01-02 18:11:12" with an implied UTC,
 overrides "l" option.

 Internally uses a circular list of buffers to avoid problems
 using AsString multiple times in a single statement.
void Copy(TTimeStamp& ts) const
 Copy this to ts.
UInt_t GetDate(Bool_t inUTC = kTRUE, Int_t secOffset = 0, UInt_t* year = 0, UInt_t* month = 0, UInt_t* day = 0) const
 Return date in form of 19971224 (i.e. 24/12/1997),
 if non-zero pointers supplied for year, month, day fill those as well.
UInt_t GetTime(Bool_t inUTC = kTRUE, Int_t secOffset = 0, UInt_t* hour = 0, UInt_t* min = 0, UInt_t* sec = 0) const
 Return time in form of 123623 (i.e. 12:36:23),
 if non-zero pointers supplied for hour, min, sec fill those as well.
Int_t GetDayOfYear(Bool_t inUTC = kTRUE, Int_t secOffset = 0) const
 Get the day of the year represented by this time stamp value.
 Valid return values range between 1 and 366, where January 1 = 1.
Int_t GetDayOfWeek(Bool_t inUTC = kTRUE, Int_t secOffset = 0) const
 Method is using Zeller's formula for calculating the day number.
 Valid return values range between 1 and 7, where Monday = 1.
Int_t GetMonth(Bool_t inUTC = kTRUE, Int_t secOffset = 0) const
 Get the month of the year. Valid return values are between 1 and 12.
Int_t GetWeek(Bool_t inUTC = kTRUE, Int_t secOffset = 0) const
 Get the week of the year. Valid week values are between 1 and 53.
 The return value is the year*100+week (1 Jan may be in the last
 week of the previous year so the year must be returned too).
Bool_t IsLeapYear(Bool_t inUTC = kTRUE, Int_t secOffset = 0) const
 Is the year a leap year.
 The calendar year is 365 days long, unless the year is exactly divisible
 by 4, in which case an extra day is added to February to make the year
 366 days long. If the year is the last year of a century, eg. 1700, 1800,
 1900, 2000, then it is only a leap year if it is exactly divisible by
 400. Therefore, 1900 wasn't a leap year but 2000 was. The reason for
 these rules is to bring the average length of the calendar year into
 line with the length of the Earth's orbit around the Sun, so that the
 seasons always occur during the same months each year.
Int_t GetZoneOffset()
 Static method returning local (current) time zone offset from UTC.
 This is the value in seconds one must add to the local time to arrive at
 Coordinated Universal Time, so it is negative east of the Prime Meridian.
void Add(const TTimeStamp& offset)
 Add "offset" as a delta time.
void Print(Option_t* option = "") const
 Print date and time.
void Set()
 Set Date/Time to current time as reported by the system.
 No accounting for nanoseconds with std ANSI functions,
 ns part faked so that subsequent calls simply add 1 to it
 this ensures that calls within the same second come back
 distinct (and sortable). Time is since Jan 1, 1970.
void Set(Int_t year, Int_t month, Int_t day, Int_t hour, Int_t min, Int_t sec, Int_t nsec, Bool_t isUTC, Int_t secOffset)
 Set Date/Time from components.

 Month & day both use normal 1..12 and 1..31 counting,
 hours, min, sec run from 0 to 23, 59, 59 respectively,
 secOffset provides method for adjusting for alternative timezones

 "year"  |    0    1 ... 37 | 38...69   |   70 .. 100  101 ..  137
 true    | 2000 2001   2037 | undefined | 1970   2000 2001 .. 2037

 "year"  | 138...1969 | 1970 .. 2037 | ...
 true    | undefined  | 1970 .. 2037 | undefined

void Set(Int_t date, Int_t time, Int_t nsec, Bool_t isUTC, Int_t secOffset)
 Set date/time from integers of the form [yy]YYMMDD and HHMMSS,
 assume UTC (UTC) components:

  MM: 01=January .. 12=December
  DD: 01 .. 31

  HH: 00=midnight .. 23
  MM: 00 .. 59
  SS: 00 .. 69

 Date must be in format 980418 or 19980418
                       1001127 or 20001127  (i.e. year 100 = 2000),
 time must be in format 224512 (second precision),
 date must be >= 700101.
void Set(UInt_t tloc, Bool_t isUTC, Int_t secOffset, Bool_t dosDate)
 The input arg is a time_t value returned by time() or a value
 returned by Convert(). This value is the number of seconds since
 the EPOCH (i.e. 00:00:00 on Jan 1m 1970). If dosDate is true then
 the input is a dosDate value.
void NormalizeNanoSec()
 Ensure that the fNanoSec field is in range [0,99999999].
time_t MktimeFromUTC(tm_t* tmstruct)
 Equivalent of standard routine "mktime" but
 using the assumption that tm struct is filled with UTC, not local, time.

 This version *ISN'T* configured to handle every possible
 weirdness of out-of-range values in the case of normalizing
 the tm struct.

 This version *DOESN'T* correctly handle values that can't be
 fit into a time_t (i.e. beyond year 2038-01-18 19:14:07, or
 before the start of Epoch).
Int_t GetDayOfYear(Int_t day, Int_t month, Int_t year)
 Get the day of the year represented by day, month and year.
 Valid return values range between 1 and 366, where January 1 = 1.
Int_t GetDayOfWeek(Int_t day, Int_t month, Int_t year)
 Method is using Zeller's formula for calculating the day number.
 Valid return values range between 1 and 7, where Monday = 1.
Int_t GetWeek(Int_t day, Int_t month, Int_t year)
 Get the week of the year. Valid week values are between 1 and 53.
 The return value is the year*100+week (1 Jan may be in the last
 week of the previous year so the year must be returned too).
Bool_t IsLeapYear(Int_t year)
 Is the given year a leap year.
 The calendar year is 365 days long, unless the year is exactly divisible
 by 4, in which case an extra day is added to February to make the year
 366 days long. If the year is the last year of a century, eg. 1700, 1800,
 1900, 2000, then it is only a leap year if it is exactly divisible by
 400. Therefore, 1900 wasn't a leap year but 2000 was. The reason for
 these rules is to bring the average length of the calendar year into
 line with the length of the Earth's orbit around the Sun, so that the
 seasons always occur during the same months each year.
void DumpTMStruct(const tm_t& tmstruct)
 Print out the "tm" structure:
 tmstruct.tm_year = year;    // years since 1900
 tmstruct.tm_mon  = month-1; // months since Jan [0,11]
 tmstruct.tm_mday = day;     // day of the month [1,31]
 tmstruct.tm_hour = hour;    // hours since midnight [0,23]
 tmstruct.tm_min  = min;     // minutes after the hour [0,59]
 tmstruct.tm_sec  = sec;     // seconds after the minute [0,59]
 tmstruct.tm_wday            // day of week [0,6]
 tmstruct.tm_yday            // days in year [0,365]
 tmstruct.tm_isdst           // DST [-1/0/1]  (unknown,false,true)
TTimeStamp()
 empty ctor (builds current time with nsec field incremented from static)
TTimeStamp(const timespec_t& ts)
 construction from timespec struct
TTimeStamp(time_t t, Int_t nsec)
 construction from time_t and separate nsec
virtual ~TTimeStamp()
{ }
void SetSec(Int_t sec)
 direct setters
{ fSec = sec; }
void SetNanoSec(Int_t nsec)
{ fNanoSec = nsec; }
timespec_t GetTimeSpec() const
time_t GetSec() const
{ return fSec; }
Int_t GetNanoSec() const
{ return fNanoSec; }
Double_t AsDouble() const
{ return fSec + 1e-9 * fNanoSec; }
Double_t AsJulianDate() const
{ return (AsDouble()/86400.0 + 2440587.5); }
operator double() const
{ return AsDouble(); }