library: libCore #include "TTimeStamp.h"

# TTimeStamp

class description - source file - inheritance tree (.pdf)

## class TTimeStamp

| Inheritance Chart:

`TTimeStamp`

        private:

          void NormalizeNanoSec()

        public:

                          TTimeStamp()
                          TTimeStamp(const timespec& ts)
                          TTimeStamp(time_t t, Int_t nsec)
                          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)
                          TTimeStamp(UInt_t date, UInt_t time, UInt_t nsec, Bool_t isUTC = kTRUE, Int_t secOffset = 0)
                          TTimeStamp(UInt_t tloc, Bool_t isUTC = kTRUE, Int_t secOffset = 0, Bool_t dosDate = kFALSE)
                          TTimeStamp(const TTimeStamp&)
                  virtual ~TTimeStamp()
                     void Add(const TTimeStamp& offset)
              const char* AsString(Option_t* option = "") const
           static TClass* Class()
                     void Copy(TTimeStamp& ts) const
              static void DumpTMStruct(const tm_t& tmstruct)
                   UInt_t GetDate(Bool_t inUTC = kTRUE, Int_t secOffset = 0, UInt_t* year = 0, UInt_t* month = 0, UInt_t* day = 0) const
                    Int_t GetDayOfWeek(Bool_t inUTC = kTRUE, Int_t secOffset = 0) const
             static Int_t GetDayOfWeek(Int_t day, Int_t month, Int_t year)
                    Int_t GetDayOfYear(Bool_t inUTC = kTRUE, Int_t secOffset = 0) const
             static Int_t GetDayOfYear(Int_t day, Int_t month, Int_t year)
                    Int_t GetMonth(Bool_t inUTC = kTRUE, Int_t secOffset = 0) const
                    Int_t GetNanoSec() const
                   time_t GetSec() const
                   UInt_t GetTime(Bool_t inUTC = kTRUE, Int_t secOffset = 0, UInt_t* hour = 0, UInt_t* min = 0, UInt_t* sec = 0) const
               timespec GetTimeSpec() const
                    Int_t GetWeek(Bool_t inUTC = kTRUE, Int_t secOffset = 0) const
             static Int_t GetWeek(Int_t day, Int_t month, Int_t year)
             static Int_t GetZoneOffset()
          virtual TClass* IsA() const
                   Bool_t IsLeapYear(Bool_t inUTC = kTRUE, Int_t secOffset = 0) const
            static Bool_t IsLeapYear(Int_t year)
            static time_t MktimeFromUTC(tm_t* tmstruct)
                   double operator double() const
              TTimeStamp& operator=(const TTimeStamp&)
                     void Print(Option_t* option = "") const
                     void Set()
                     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)
                     void Set(Int_t date, Int_t time, Int_t nsec, Bool_t isUTC, Int_t secOffset)
                     void Set(UInt_t tloc, Bool_t isUTC, Int_t secOffset, Bool_t dosDate)
             virtual void ShowMembers(TMemberInspector& insp, char* parent)
             virtual void Streamer(TBuffer& b)
                     void StreamerNVirtual(TBuffer& b)

### Data Members

        private:

          Int_t fSec      seconds
          Int_t fNanoSec  nanoseconds

## Class Description

     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.

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, Bool_t isUTC, Int_t secOffset)

     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, Int_t secOffset)

     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, Int_t secOffset, Bool_t dosDate)

     Create a TTimeStamp and set it to the the 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.

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, Int_t secOffset, UInt_t *year, UInt_t *month, UInt_t *day) 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, Int_t secOffset, UInt_t *hour, UInt_t *min, UInt_t *sec) 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, Int_t secOffset) 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, Int_t secOffset) 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, Int_t secOffset) const

     Get the month of the year. Valid return values are between 1 and 12.

Int_t GetWeek(Bool_t inUTC, Int_t secOffset) 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, Int_t secOffset) 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
     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 difference in seconds between UTC and local standard time.

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
     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)

### Inline Functions

                   void ~TTimeStamp()
             TTimeStamp TTimeStamp(UInt_t date, UInt_t time, UInt_t nsec, Bool_t isUTC = kTRUE, Int_t secOffset = 0)
             TTimeStamp TTimeStamp(UInt_t tloc, Bool_t isUTC = kTRUE, Int_t secOffset = 0, Bool_t dosDate = kFALSE)
             timespec GetTimeSpec() const
                 time_t GetSec() const
                  Int_t GetNanoSec() const
                 double operator double() const
                TClass* Class()
                TClass* IsA() const
                   void ShowMembers(TMemberInspector& insp, char* parent)
                   void Streamer(TBuffer& b)
                   void StreamerNVirtual(TBuffer& b)
             TTimeStamp TTimeStamp(const TTimeStamp&)
            TTimeStamp& operator=(const TTimeStamp&)

Author: R. Hatcher 30/9/2001
Last update: root/base:$Name: $:$Id: TTimeStamp.cxx,v 1.20 2005/06/23 06:24:27 brun Exp $
Copyright (C) 1995-2002, Rene Brun and Fons Rademakers. *