TTimeStamp


class description - source file - inheritance tree

class TTimeStamp

    private:
void NormalizeNanoSec() 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) public:
TTimeStamp TTimeStamp() TTimeStamp TTimeStamp(const timespec& ts) TTimeStamp TTimeStamp(long t, Int_t nsec) TTimeStamp 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 TTimeStamp(UInt_t date, UInt_t time, UInt_t nsec, Bool_t isUTC = kTRUE, Int_t secOffset = 0) TTimeStamp TTimeStamp(const TTimeStamp&) virtual void ~TTimeStamp() void Add(const TTimeStamp& offset) const char* AsString(const 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 GetNanoSec() const long 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 static Int_t GetZoneOffset() virtual TClass* IsA() const static Bool_t IsLeapYear(Int_t year) static long MktimeFromUTC(tm_t* tmstruct) void Print(const Option_t* option) const 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.

const char* 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 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 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.

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


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


Author: R. Hatcher 30/9/2001
Last update: root/base:$Name: $:$Id: TTimeStamp.cxx,v 1.11 2002/12/02 18:50:01 rdm Exp $
Copyright (C) 1995-2002, Rene Brun and Fons Rademakers. *


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