{
// we allow for the leap seconds, although we don't use them (yet)
return (year != wxDateTime::Inv_Year) && (mon != wxDateTime::Inv_Month) &&
- (mday < GetNumOfDaysInMonth(year, mon)) &&
+ (mday <= GetNumOfDaysInMonth(year, mon)) &&
(hour < 24) && (min < 60) && (sec < 62) && (msec < 1000);
}
void wxDateTime::Tm::ComputeWeekDay()
{
- wxFAIL_MSG(_T("TODO"));
+ // compute the week day from day/month/year: we use the dumbest algorithm
+ // possible: just compute our JDN and then use the (simple to derive)
+ // formula: weekday = (JDN + 1.5) % 7
+ wday = (wxDateTime::WeekDay)(GetTruncatedJDN(mday, mon, year) + 2) % 7;
}
void wxDateTime::Tm::AddMonths(int monDiff)
// and offset it by the number of days needed to get the correct wday
tm.tm_mday += wday;
+ // call mktime() to normalize it...
+ (void)mktime(&tm);
+
+ // ... and call strftime()
return CallStrftime(abbr ? _T("%a") : _T("%A"), &tm);
}
{
// we are working with local time
tm = localtime(&time);
+
+ // should never happen
+ wxCHECK_MSG( tm, Tm(), _T("gmtime() failed") );
}
else
{
time += tz.GetOffset();
- tm = gmtime(&time);
- }
+ if ( time >= 0 )
+ {
+ tm = gmtime(&time);
- // should never happen
- wxCHECK_MSG( tm, Tm(), _T("gmtime() failed") );
+ // should never happen
+ wxCHECK_MSG( tm, Tm(), _T("gmtime() failed") );
+ }
+ else
+ {
+ tm = (struct tm *)NULL;
+ }
+ }
- return Tm(*tm, tz);
+ if ( tm )
+ {
+ return Tm(*tm, tz);
+ }
+ //else: use generic code below
}
- else
- {
- // remember the time and do the calculations with the date only - this
- // eliminates rounding errors of the floating point arithmetics
- wxLongLong timeMidnight = m_time + tz.GetOffset() * 1000;
+ // remember the time and do the calculations with the date only - this
+ // eliminates rounding errors of the floating point arithmetics
- long timeOnly = (timeMidnight % MILLISECONDS_PER_DAY).ToLong();
+ wxLongLong timeMidnight = m_time + tz.GetOffset() * 1000;
- // we want to always have positive time and timeMidnight to be really
- // the midnight before it
- if ( timeOnly < 0 )
- {
- timeOnly = MILLISECONDS_PER_DAY + timeOnly;
- }
+ long timeOnly = (timeMidnight % MILLISECONDS_PER_DAY).ToLong();
- timeMidnight -= timeOnly;
+ // we want to always have positive time and timeMidnight to be really
+ // the midnight before it
+ if ( timeOnly < 0 )
+ {
+ timeOnly = MILLISECONDS_PER_DAY + timeOnly;
+ }
- // calculate the Gregorian date from JDN for the midnight of our date:
- // this will yield day, month (in 1..12 range) and year
+ timeMidnight -= timeOnly;
- // actually, this is the JDN for the noon of the previous day
- long jdn = (timeMidnight / MILLISECONDS_PER_DAY).ToLong() + EPOCH_JDN;
+ // calculate the Gregorian date from JDN for the midnight of our date:
+ // this will yield day, month (in 1..12 range) and year
- // CREDIT: code below is by Scott E. Lee (but bugs are mine)
+ // actually, this is the JDN for the noon of the previous day
+ long jdn = (timeMidnight / MILLISECONDS_PER_DAY).ToLong() + EPOCH_JDN;
- wxASSERT_MSG( jdn > -2, _T("JDN out of range") );
+ // CREDIT: code below is by Scott E. Lee (but bugs are mine)
- // calculate the century
- int temp = (jdn + JDN_OFFSET) * 4 - 1;
- int century = temp / DAYS_PER_400_YEARS;
+ wxASSERT_MSG( jdn > -2, _T("JDN out of range") );
- // then the year and day of year (1 <= dayOfYear <= 366)
- temp = ((temp % DAYS_PER_400_YEARS) / 4) * 4 + 3;
- int year = (century * 100) + (temp / DAYS_PER_4_YEARS);
- int dayOfYear = (temp % DAYS_PER_4_YEARS) / 4 + 1;
+ // calculate the century
+ int temp = (jdn + JDN_OFFSET) * 4 - 1;
+ int century = temp / DAYS_PER_400_YEARS;
- // and finally the month and day of the month
- temp = dayOfYear * 5 - 3;
- int month = temp / DAYS_PER_5_MONTHS;
- int day = (temp % DAYS_PER_5_MONTHS) / 5 + 1;
+ // then the year and day of year (1 <= dayOfYear <= 366)
+ temp = ((temp % DAYS_PER_400_YEARS) / 4) * 4 + 3;
+ int year = (century * 100) + (temp / DAYS_PER_4_YEARS);
+ int dayOfYear = (temp % DAYS_PER_4_YEARS) / 4 + 1;
- // month is counted from March - convert to normal
- if ( month < 10 )
- {
- month += 3;
- }
- else
- {
- year += 1;
- month -= 9;
- }
+ // and finally the month and day of the month
+ temp = dayOfYear * 5 - 3;
+ int month = temp / DAYS_PER_5_MONTHS;
+ int day = (temp % DAYS_PER_5_MONTHS) / 5 + 1;
- // year is offset by 4800
- year -= 4800;
+ // month is counted from March - convert to normal
+ if ( month < 10 )
+ {
+ month += 3;
+ }
+ else
+ {
+ year += 1;
+ month -= 9;
+ }
- // check that the algorithm gave us something reasonable
- wxASSERT_MSG( (0 < month) && (month <= 12), _T("invalid month") );
- wxASSERT_MSG( (1 <= day) && (day < 32), _T("invalid day") );
- wxASSERT_MSG( (INT_MIN <= year) && (year <= INT_MAX),
- _T("year range overflow") );
+ // year is offset by 4800
+ year -= 4800;
- // construct Tm from these values
- Tm tm;
- tm.year = (int)year;
- tm.mon = (Month)(month - 1); // algorithm yields 1 for January, not 0
- tm.mday = (wxDateTime_t)day;
- tm.msec = timeOnly % 1000;
- timeOnly -= tm.msec;
- timeOnly /= 1000; // now we have time in seconds
+ // check that the algorithm gave us something reasonable
+ wxASSERT_MSG( (0 < month) && (month <= 12), _T("invalid month") );
+ wxASSERT_MSG( (1 <= day) && (day < 32), _T("invalid day") );
+ wxASSERT_MSG( (INT_MIN <= year) && (year <= INT_MAX),
+ _T("year range overflow") );
- tm.sec = timeOnly % 60;
- timeOnly -= tm.sec;
- timeOnly /= 60; // now we have time in minutes
+ // construct Tm from these values
+ Tm tm;
+ tm.year = (int)year;
+ tm.mon = (Month)(month - 1); // algorithm yields 1 for January, not 0
+ tm.mday = (wxDateTime_t)day;
+ tm.msec = timeOnly % 1000;
+ timeOnly -= tm.msec;
+ timeOnly /= 1000; // now we have time in seconds
- tm.min = timeOnly % 60;
- timeOnly -= tm.min;
+ tm.sec = timeOnly % 60;
+ timeOnly -= tm.sec;
+ timeOnly /= 60; // now we have time in minutes
- tm.hour = timeOnly / 60;
+ tm.min = timeOnly % 60;
+ timeOnly -= tm.min;
- return tm;
- }
+ tm.hour = timeOnly / 60;
+
+ return tm;
}
wxDateTime& wxDateTime::SetYear(int year)
{
// we are working with local time
tm = localtime(&time);
+
+ // should never happen
+ wxCHECK_MSG( tm, wxEmptyString, _T("localtime() failed") );
}
else
{
time += tz.GetOffset();
- tm = gmtime(&time);
- }
+ if ( time >= 0 )
+ {
+ tm = gmtime(&time);
- // should never happen
- wxCHECK_MSG( tm, _T(""), _T("gmtime() failed") );
+ // should never happen
+ wxCHECK_MSG( tm, wxEmptyString, _T("gmtime() failed") );
+ }
+ else
+ {
+ tm = (struct tm *)NULL;
+ }
+ }
- return CallStrftime(format, tm);
- }
- else
- {
- // use a hack and still use strftime(): make a copy of the format and
- // replace all occurences of YEAR in it with some unique string not
- // appearing anywhere else in it, then use strftime() to format the
- // date in year YEAR and then replace YEAR back by the real year and
- // the unique replacement string back with YEAR where YEAR is any year
- // in the range supported by strftime() (1970 - 2037) which is equal to
- // the real year modulo 28 (so the week days coincide for them)
-
- // find the YEAR
- int yearReal = GetYear(tz);
- int year = 1970 + yearReal % 28;
-
- wxString strYear;
- strYear.Printf(_T("%d"), year);
-
- // find a string not occuring in format (this is surely not optimal way
- // of doing it... improvements welcome!)
- wxString fmt = format;
- wxString replacement = (wxChar)-1;
- while ( fmt.Find(replacement) != wxNOT_FOUND )
+ if ( tm )
{
- replacement << (wxChar)-1;
+ return CallStrftime(format, tm);
}
+ //else: use generic code below
+ }
+
+ // use a hack and still use strftime(): first find the YEAR which is a year
+ // in the strftime() range (1970 - 2038) whose Jan 1 falls on the same week
+ // day as the Jan 1 of the real year. Then make a copy of the format and
+ // replace all occurences of YEAR in it with some unique string not
+ // appearing anywhere else in it, then use strftime() to format the date in
+ // year YEAR and then replace YEAR back by the real year and the unique
+ // replacement string back with YEAR. Notice that "all occurences of YEAR"
+ // means all occurences of 4 digit as well as 2 digit form!
- // replace all occurences of year with it
- bool wasReplaced = fmt.Replace(strYear, replacement) > 0;
+ // NB: may be it would be simpler to "honestly" reimplement strftime()?
- // use strftime() to format the same date but in supported year
- wxDateTime dt(*this);
- dt.SetYear(year);
- wxString str = dt.Format(format, tz);
+ // find the YEAR: normally, for any year X, Jan 1 or the year X + 28 is the
+ // same weekday as Jan 1 of X (because the weekday advances by 1 for each
+ // normal X and by 2 for each leap X, hence by 5 every 4 years or by 35
+ // which is 0 mod 7 every 28 years) but this rule breaks down if there are
+ // years between X and Y which are divisible by 4 but not leap (i.e.
+ // divisible by 100 but not 400), hence the correction.
- // now replace the occurence of 1999 with the real year
- wxString strYearReal;
- strYearReal.Printf(_T("%d"), yearReal);
- str.Replace(strYear, strYearReal);
+ int yearReal = GetYear(tz);
+ int year = 1970 + yearReal % 28;
- // and replace back all occurences of replacement string
- if ( wasReplaced )
- str.Replace(replacement, strYear);
+ int nCenturiesInBetween = (year / 100) - (yearReal / 100);
+ int nLostWeekDays = nCenturiesInBetween - (nCenturiesInBetween / 400);
- return str;
+ // we have to gain back the "lost" weekdays...
+ while ( (nLostWeekDays % 7) != 0 )
+ {
+ nLostWeekDays += year++ % 4 ? 1 : 2;
}
+
+ // at any rate, we can't go further than 1997 + 28!
+ wxASSERT_MSG( year < 2030, _T("logic error in wxDateTime::Format") );
+
+ wxString strYear, strYear2;
+ strYear.Printf(_T("%d"), year);
+ strYear2.Printf(_T("%d"), year % 100);
+
+ // find two strings not occuring in format (this is surely not optimal way
+ // of doing it... improvements welcome!)
+ wxString fmt = format;
+ wxString replacement = (wxChar)-1;
+ while ( fmt.Find(replacement) != wxNOT_FOUND )
+ {
+ replacement << (wxChar)-1;
+ }
+
+ wxString replacement2 = (wxChar)-2;
+ while ( fmt.Find(replacement) != wxNOT_FOUND )
+ {
+ replacement << (wxChar)-2;
+ }
+
+ // replace all occurences of year with it
+ bool wasReplaced = fmt.Replace(strYear, replacement) > 0;
+ if ( !wasReplaced )
+ wasReplaced = fmt.Replace(strYear2, replacement2) > 0;
+
+ // use strftime() to format the same date but in supported year
+ wxDateTime dt(*this);
+ dt.SetYear(year);
+ wxString str = dt.Format(format, tz);
+
+ // now replace the occurence of 1999 with the real year
+ wxString strYearReal, strYearReal2;
+ strYearReal.Printf(_T("%04d"), yearReal);
+ strYearReal2.Printf(_T("%02d"), yearReal % 100);
+ str.Replace(strYear, strYearReal);
+ str.Replace(strYear2, strYearReal2);
+
+ // and replace back all occurences of replacement string
+ if ( wasReplaced )
+ {
+ str.Replace(replacement2, strYear2);
+ str.Replace(replacement, strYear);
+ }
+
+ return str;
}
// ============================================================================
projects / wxWidgets.git / commitdiff
