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more timezone stuff - it's a miracle, but it seems to work

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git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@4896 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
This commit is contained in:
Vadim Zeitlin
1999-12-10 20:44:37 +00:00
parent e4b8154a65
commit 299fcbfe98
4 changed files with 316 additions and 160 deletions
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141
src/common/datetime.cpp
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@@ -20,7 +20,8 @@
* Implementation notes:
*
* 1. the time is stored as a 64bit integer containing the signed number of
* milliseconds since Jan 1. 1970 (the Unix Epoch)
* milliseconds since Jan 1. 1970 (the Unix Epoch) - so it is always
* expressed in GMT.
*
* 2. the range is thus something about 580 million years, but due to current
* algorithms limitations, only dates from Nov 24, 4714BC are handled
@@ -33,6 +34,14 @@
* algorithm used by Scott E. Lee's code only works for positive JDNs, more
* or less)
*
* 5. the object constructed for the given DD-MM-YYYY HH:MM:SS corresponds to
* this moment in local time and may be converted to the object
* corresponding to the same date/time in another time zone by using
* ToTimezone()
*
* 6. the conversions to the current (or any other) timezone are done when the
* internal time representation is converted to the broken-down one in
* wxDateTime::Tm.
*/
// ============================================================================
@@ -244,7 +253,8 @@ wxDateTime::Tm::Tm()
wday = wxDateTime::Inv_WeekDay;
}
wxDateTime::Tm::Tm(const struct tm& tm)
wxDateTime::Tm::Tm(const struct tm& tm, const TimeZone& tz)
: m_tz(tz)
{
msec = 0;
sec = tm.tm_sec;
@@ -321,7 +331,9 @@ wxDateTime::TimeZone::TimeZone(wxDateTime::TZ tz)
switch ( tz )
{
case wxDateTime::Local:
// leave offset to be 0
// get the offset from C RTL: it returns the difference GMT-local
// while we want to have the offset _from_ GMT, hence the '-'
m_offset = -GetTimeZone();
break;
case wxDateTime::GMT_12:
@@ -336,7 +348,7 @@ wxDateTime::TimeZone::TimeZone(wxDateTime::TZ tz)
case wxDateTime::GMT_3:
case wxDateTime::GMT_2:
case wxDateTime::GMT_1:
m_offset = -60*(wxDateTime::GMT0 - tz);
m_offset = -3600*(wxDateTime::GMT0 - tz);
break;
case wxDateTime::GMT0:
@@ -352,12 +364,12 @@ wxDateTime::TimeZone::TimeZone(wxDateTime::TZ tz)
case wxDateTime::GMT10:
case wxDateTime::GMT11:
case wxDateTime::GMT12:
m_offset = 60*(tz - wxDateTime::GMT0);
m_offset = 3600*(tz - wxDateTime::GMT0);
break;
case wxDateTime::A_CST:
// Central Standard Time in use in Australia = UTC + 9.5
m_offset = 9*60 + 30;
m_offset = 60*(9*60 + 30);
break;
default:
@@ -533,30 +545,14 @@ wxString wxDateTime::GetWeekDayName(wxDateTime::WeekDay wday, bool abbr)
// constructors and assignment operators
// ----------------------------------------------------------------------------
wxDateTime& wxDateTime::Set(const struct tm& tm1)
// the values in the tm structure contain the local time
wxDateTime& wxDateTime::Set(const struct tm& tm)
{
wxASSERT_MSG( IsValid(), _T("invalid wxDateTime") );
tm tm2(tm1);
// we want the time in GMT, mktime() takes the local time, so use timegm()
// if it's available
#ifdef HAVE_TIMEGM
time_t timet = timegm(&tm2);
#else // !HAVE_TIMEGM
// FIXME this almost surely doesn't work
tm2.tm_sec -= GetTimeZone();
struct tm tm2(tm);
time_t timet = mktime(&tm2);
if ( tm2.tm_isdst )
{
tm2.tm_hour += 1;
timet = mktime(&tm2);
}
#endif // HAVE_TIMEGM/!HAVE_TIMEGM
if ( timet == (time_t)(-1) )
{
wxFAIL_MSG(_T("Invalid time"));
@@ -584,7 +580,9 @@ wxDateTime& wxDateTime::Set(wxDateTime_t hour,
// get the current date from system
time_t timet = GetTimeNow();
struct tm *tm = gmtime(&timet);
struct tm *tm = localtime(&timet);
wxCHECK_MSG( tm, ms_InvDateTime, _T("localtime() failed") );
// adjust the time
tm->tm_hour = hour;
@@ -634,7 +632,7 @@ wxDateTime& wxDateTime::Set(wxDateTime_t day,
tm.tm_hour = hour;
tm.tm_min = minute;
tm.tm_sec = second;
tm.tm_isdst = -1; // mktime() will guess it (wrongly, probably)
tm.tm_isdst = -1; // mktime() will guess it
(void)Set(tm);
@@ -651,7 +649,8 @@ wxDateTime& wxDateTime::Set(wxDateTime_t day,
m_time -= EPOCH_JDN;
m_time *= SECONDS_PER_DAY * TIME_T_FACTOR;
Add(wxTimeSpan(hour, minute, second, millisec));
// JDN corresponds to GMT, we take localtime
Add(wxTimeSpan(hour, minute, second + GetTimeZone(), millisec));
}
return *this;
@@ -673,7 +672,7 @@ wxDateTime& wxDateTime::Set(double jdn)
// time_t <-> broken down time conversions
// ----------------------------------------------------------------------------
wxDateTime::Tm wxDateTime::GetTm() const
wxDateTime::Tm wxDateTime::GetTm(const TimeZone& tz) const
{
wxASSERT_MSG( IsValid(), _T("invalid wxDateTime") );
@@ -681,24 +680,36 @@ wxDateTime::Tm wxDateTime::GetTm() const
if ( time != (time_t)-1 )
{
// use C RTL functions
tm *tm = gmtime(&time);
tm *tm;
if ( tz.GetOffset() == -GetTimeZone() )
{
// we are working with local time
tm = localtime(&time);
}
else
{
tm = gmtime(&time);
}
// should never happen
wxCHECK_MSG( tm, Tm(), _T("gmtime() failed") );
return Tm(*tm);
return Tm(*tm, tz);
}
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;
wxLongLong timeMidnight = m_time - GetTimeZone() * 1000;
long timeOnly = (m_time % MILLISECONDS_PER_DAY).ToLong();
long timeOnly = (timeMidnight % MILLISECONDS_PER_DAY).ToLong();
// we want to always have positive time and timeMidnight to be really
// the midnight before it
if ( timeOnly < 0 )
{
timeOnly = MILLISECONDS_PER_DAY - timeOnly;
timeOnly = MILLISECONDS_PER_DAY + timeOnly;
}
timeMidnight -= timeOnly;
@@ -950,7 +961,8 @@ bool wxDateTime::SetToWeekDay(WeekDay weekday,
double wxDateTime::GetJulianDayNumber() const
{
Tm tm(GetTm());
// JDN are always expressed for the GMT dates
Tm tm(ToTimezone(GMT0).GetTm(GMT0));
double result = GetTruncatedJDN(tm.mday, tm.mon, tm.year);
@@ -968,31 +980,51 @@ double wxDateTime::GetRataDie() const
}
// ----------------------------------------------------------------------------
// timezone stuff
// timezone and DST stuff
// ----------------------------------------------------------------------------
wxDateTime& wxDateTime::MakeUTC()
int wxDateTime::IsDST(wxDateTime::Country country) const
{
return Add(wxTimeSpan::Seconds(GetTimeZone()));
wxCHECK_MSG( country == Country_Default, -1,
_T("country support not implemented") );
// use the C RTL for the dates in the standard range
time_t timet = GetTicks();
if ( timet != (time_t)-1 )
{
tm *tm = localtime(&timet);
wxCHECK_MSG( tm, -1, _T("localtime() failed") );
return tm->tm_isdst;
}
else
{
// wxFAIL_MSG( _T("TODO") );
return -1;
}
}
wxDateTime& wxDateTime::MakeTimezone(const TimeZone& tz)
{
int minDiff = GetTimeZone() / SECONDS_IN_MINUTE + tz.GetOffset();
return Add(wxTimeSpan::Minutes(minDiff));
}
int secDiff = GetTimeZone() + tz.GetOffset();
wxDateTime& wxDateTime::MakeLocalTime(const TimeZone& tz)
{
int minDiff = GetTimeZone() / SECONDS_IN_MINUTE + tz.GetOffset();
return Substract(wxTimeSpan::Minutes(minDiff));
// we need to know whether DST is or not in effect for this date
if ( IsDST() == 1 )
{
// FIXME we assume that the DST is always shifted by 1 hour
secDiff -= 3600;
}
return Substract(wxTimeSpan::Seconds(secDiff));
}
// ----------------------------------------------------------------------------
// wxDateTime to/from text representations
// ----------------------------------------------------------------------------
wxString wxDateTime::Format(const wxChar *format) const
wxString wxDateTime::Format(const wxChar *format, const TimeZone& tz) const
{
wxCHECK_MSG( format, _T(""), _T("NULL format in wxDateTime::Format") );
@@ -1000,7 +1032,18 @@ wxString wxDateTime::Format(const wxChar *format) const
if ( time != (time_t)-1 )
{
// use strftime()
tm *tm = gmtime(&time);
tm *tm;
if ( tz.GetOffset() == -GetTimeZone() )
{
// we are working with local time
tm = localtime(&time);
}
else
{
time += tz.GetOffset();
tm = gmtime(&time);
}
// should never happen
wxCHECK_MSG( tm, _T(""), _T("gmtime() failed") );
@@ -1018,7 +1061,7 @@ wxString wxDateTime::Format(const wxChar *format) const
// the real year modulo 28 (so the week days coincide for them)
// find the YEAR
int yearReal = GetYear();
int yearReal = GetYear(tz);
int year = 1970 + yearReal % 28;
wxString strYear;
@@ -1039,7 +1082,7 @@ wxString wxDateTime::Format(const wxChar *format) const
// use strftime() to format the same date but in supported year
wxDateTime dt(*this);
dt.SetYear(year);
wxString str = dt.Format(format);
wxString str = dt.Format(format, tz);
// now replace the occurence of 1999 with the real year
wxString strYearReal;