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wxDateTime progress: DST compuation, weekday computation, day-in-year and week

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number computations all implemented and seem to work


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@5026 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
This commit is contained in:
Vadim Zeitlin
1999-12-17 19:56:32 +00:00
parent 3e1ed7d709
commit 239446b415
4 changed files with 695 additions and 45 deletions
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343
src/common/datetime.cpp
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@@ -300,6 +300,8 @@ void wxDateTime::Tm::AddMonths(int monDiff)
while ( monDiff + mon > MONTHS_IN_YEAR )
{
year++;
monDiff -= MONTHS_IN_YEAR;
}
mon = (wxDateTime::Month)(mon + monDiff);
@@ -421,12 +423,6 @@ int wxDateTime::GetCentury(int year)
return year > 0 ? year / 100 : year / 100 - 1;
}
/* static */
void wxDateTime::SetCountry(wxDateTime::Country country)
{
ms_country = country;
}
/* static */
int wxDateTime::ConvertYearToBC(int year)
{
@@ -552,6 +548,281 @@ wxString wxDateTime::GetWeekDayName(wxDateTime::WeekDay wday, bool abbr)
return CallStrftime(abbr ? _T("%a") : _T("%A"), &tm);
}
// ----------------------------------------------------------------------------
// Country stuff: date calculations depend on the country (DST, work days,
// ...), so we need to know which rules to follow.
// ----------------------------------------------------------------------------
/* static */
wxDateTime::Country wxDateTime::GetCountry()
{
if ( ms_country == Country_Unknown )
{
// try to guess from the time zone name
time_t t = time(NULL);
struct tm *tm = localtime(&t);
wxString tz = CallStrftime(_T("%Z"), tm);
if ( tz == _T("WET") || tz == _T("WEST") )
{
ms_country = UK;
}
else if ( tz == _T("CET") || tz == _T("CEST") )
{
ms_country = Country_EEC;
}
else if ( tz == _T("MSK") || tz == _T("MSD") )
{
ms_country = Russia;
}
else if ( tz == _T("AST") || tz == _T("ADT") ||
tz == _T("EST") || tz == _T("EDT") ||
tz == _T("CST") || tz == _T("CDT") ||
tz == _T("MST") || tz == _T("MDT") ||
tz == _T("PST") || tz == _T("PDT") )
{
ms_country = USA;
}
else
{
// well, choose a default one
ms_country = USA;
}
}
return ms_country;
}
/* static */
void wxDateTime::SetCountry(wxDateTime::Country country)
{
ms_country = country;
}
/* static */
bool wxDateTime::IsWestEuropeanCountry(Country country)
{
if ( country == Country_Default )
{
country = GetCountry();
}
return (Country_WesternEurope_Start <= country) &&
(country <= Country_WesternEurope_End);
}
// ----------------------------------------------------------------------------
// DST calculations: we use 3 different rules for the West European countries,
// USA and for the rest of the world. This is undoubtedly false for many
// countries, but I lack the necessary info (and the time to gather it),
// please add the other rules here!
// ----------------------------------------------------------------------------
/* static */
bool wxDateTime::IsDSTApplicable(int year, Country country)
{
if ( year == Inv_Year )
{
// take the current year if none given
year = GetCurrentYear();
}
if ( country == Country_Default )
{
country = GetCountry();
}
switch ( country )
{
case USA:
case UK:
// DST was first observed in the US and UK during WWI, reused
// during WWII and used again since 1966
return year >= 1966 ||
(year >= 1942 && year <= 1945) ||
(year == 1918 || year == 1919);
default:
// assume that it started after WWII
return year > 1950;
}
}
/* static */
wxDateTime wxDateTime::GetBeginDST(int year, Country country)
{
if ( year == Inv_Year )
{
// take the current year if none given
year = GetCurrentYear();
}
if ( country == Country_Default )
{
country = GetCountry();
}
if ( !IsDSTApplicable(year, country) )
{
return ms_InvDateTime;
}
wxDateTime dt;
if ( IsWestEuropeanCountry(country) || (country == Russia) )
{
// DST begins at 1 a.m. GMT on the last Sunday of March
if ( !dt.SetToLastWeekDay(Sun, Mar, year) )
{
// weird...
wxFAIL_MSG( _T("no last Sunday in March?") );
}
dt += wxTimeSpan::Hours(1);
dt.MakeGMT();
}
else switch ( country )
{
case USA:
switch ( year )
{
case 1918:
case 1919:
// don't know for sure - assume it was in effect all year
case 1943:
case 1944:
case 1945:
dt.Set(1, Jan, year);
break;
case 1942:
// DST was installed Feb 2, 1942 by the Congress
dt.Set(2, Feb, year);
break;
// Oil embargo changed the DST period in the US
case 1974:
dt.Set(6, Jan, 1974);
break;
case 1975:
dt.Set(23, Feb, 1975);
break;
default:
// before 1986, DST begun on the last Sunday of April, but
// in 1986 Reagan changed it to begin at 2 a.m. of the
// first Sunday in April
if ( year < 1986 )
{
if ( !dt.SetToLastWeekDay(Sun, Apr, year) )
{
// weird...
wxFAIL_MSG( _T("no first Sunday in April?") );
}
}
else
{
if ( !dt.SetToWeekDay(Sun, 1, Apr, year) )
{
// weird...
wxFAIL_MSG( _T("no first Sunday in April?") );
}
}
dt += wxTimeSpan::Hours(2);
// TODO what about timezone??
}
break;
default:
// assume Mar 30 as the start of the DST for the rest of the world
// - totally bogus, of course
dt.Set(30, Mar, year);
}
return dt;
}
/* static */
wxDateTime wxDateTime::GetEndDST(int year, Country country)
{
if ( year == Inv_Year )
{
// take the current year if none given
year = GetCurrentYear();
}
if ( country == Country_Default )
{
country = GetCountry();
}
if ( !IsDSTApplicable(year, country) )
{
return ms_InvDateTime;
}
wxDateTime dt;
if ( IsWestEuropeanCountry(country) || (country == Russia) )
{
// DST ends at 1 a.m. GMT on the last Sunday of October
if ( !dt.SetToLastWeekDay(Sun, Oct, year) )
{
// weirder and weirder...
wxFAIL_MSG( _T("no last Sunday in October?") );
}
dt += wxTimeSpan::Hours(1);
dt.MakeGMT();
}
else switch ( country )
{
case USA:
switch ( year )
{
case 1918:
case 1919:
// don't know for sure - assume it was in effect all year
case 1943:
case 1944:
dt.Set(31, Dec, year);
break;
case 1945:
// the time was reset after the end of the WWII
dt.Set(30, Sep, year);
break;
default:
// DST ends at 2 a.m. on the last Sunday of October
if ( !dt.SetToLastWeekDay(Sun, Oct, year) )
{
// weirder and weirder...
wxFAIL_MSG( _T("no last Sunday in October?") );
}
dt += wxTimeSpan::Hours(2);
// TODO what about timezone??
}
break;
default:
// assume October 26th as the end of the DST - totally bogus too
dt.Set(26, Oct, year);
}
return dt;
}
// ----------------------------------------------------------------------------
// constructors and assignment operators
// ----------------------------------------------------------------------------
@@ -960,9 +1231,9 @@ bool wxDateTime::SetToWeekDay(WeekDay weekday,
// add advance n-1 weeks more
diff += 7*(n - 1);
dt -= wxDateSpan::Days(diff);
dt += wxDateSpan::Days(diff);
}
else
else // count from the end of the month
{
// get the last day of the month
dt.SetToLastMonthDay(month, year);
@@ -976,7 +1247,7 @@ bool wxDateTime::SetToWeekDay(WeekDay weekday,
diff += 7;
// and rewind n-1 weeks from there
diff += 7*(n - 1);
diff += 7*(-n - 1);
dt -= wxDateSpan::Days(diff);
}
@@ -995,6 +1266,46 @@ bool wxDateTime::SetToWeekDay(WeekDay weekday,
}
}
wxDateTime::wxDateTime_t wxDateTime::GetDayOfYear(const TimeZone& tz) const
{
// this array contains the cumulated number of days in all previous months
// for normal and leap years
static const wxDateTime_t cumulatedDays[2][MONTHS_IN_YEAR] =
{
{ 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 },
{ 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335 }
};
Tm tm(GetTm(tz));
return cumulatedDays[IsLeapYear(tm.year)][tm.mon] + tm.mday;
}
wxDateTime::wxDateTime_t wxDateTime::GetWeekOfYear(const TimeZone& tz) const
{
// the first week of the year is the one which contains Jan, 4 (according
// to ISO standard rule), so the year day N0 = 4 + 7*W always lies in the
// week W+1. As any day N = 7*W + 4 + (N - 4)%7, it lies in the same week
// as N0 or in the next one.
// TODO this surely may be optimized - I got confused while writing it
wxDateTime_t nDayInYear = GetDayOfYear(tz);
// the week day of the day lying in the first week
WeekDay wdayStart = wxDateTime(4, Jan, GetYear()).GetWeekDay();
wxDateTime_t week = (nDayInYear - 4) / 7 + 1;
// notice that Sunday shoould be counted as 7, not 0 here!
if ( ((nDayInYear - 4) % 7) + (!wdayStart ? 7 : wdayStart) > 7 )
{
week++;
}
return week;
}
// ----------------------------------------------------------------------------
// Julian day number conversion and related stuff
// ----------------------------------------------------------------------------
@@ -1040,9 +1351,15 @@ int wxDateTime::IsDST(wxDateTime::Country country) const
}
else
{
// wxFAIL_MSG( _T("TODO") );
int year = GetYear();
return -1;
if ( !IsDSTApplicable(year, country) )
{
// no DST time in this year in this country
return -1;
}
return IsBetween(GetBeginDST(year, country), GetEndDST(year, country));
}
}
@@ -1243,7 +1560,7 @@ wxString wxTimeSpan::Format(const wxChar *format) const
break;
case 'l':
tmp.Printf(_T("%03d"), GetMilliseconds());
tmp.Printf(_T("%03d"), GetMilliseconds().GetValue());
break;
case 'M':
@@ -1251,7 +1568,7 @@ wxString wxTimeSpan::Format(const wxChar *format) const
break;
case 'S':
tmp.Printf(_T("%02d"), GetSeconds());
tmp.Printf(_T("%02d"), GetSeconds().GetValue());
break;
}