class 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).

 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);

 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.

 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.

 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.

 Copy this to ts.

 Return date in form of 19971224 (i.e. 24/12/1997),
 if non-zero pointers supplied for year, month, day fill those as well.

 Return time in form of 123623 (i.e. 12:36:23),
 if non-zero pointers supplied for hour, min, sec fill those as well.

 Get the day of the year represented by this time stamp value.
 Valid return values range between 1 and 366, where January 1 = 1.

 Method is using Zeller's formula for calculating the day number.
 Valid return values range between 1 and 7, where Monday = 1.

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

 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).

 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.

 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.

 Add "offset" as a delta time.

 Print date and time.

 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.

 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

 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.

 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.

 Ensure that the fNanoSec field is in range [0,99999999].

 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).

 Get the day of the year represented by day, month and year.
 Valid return values range between 1 and 366, where January 1 = 1.

 Method is using Zeller's formula for calculating the day number.
 Valid return values range between 1 and 7, where Monday = 1.

 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).

 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.

 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)

 empty ctor (builds current time with nsec field incremented from static)

 construction from timespec struct

 construction from time_t and separate nsec

 direct setters