-/////////////////////////////////////////////////////////////////////////////
+///////////////////////////////////////////////////////////////////////////////
// Name: wx/datetime.h
// Purpose: implementation of time/date related classes
// Author: Vadim Zeitlin
// Modified by:
// Created: 11.05.99
// RCS-ID: $Id$
-// Copyright: (c) 1998 Vadim Zeitlin <zeitlin@dptmaths.ens-cachan.fr>
+// Copyright: (c) 1999 Vadim Zeitlin <zeitlin@dptmaths.ens-cachan.fr>
+// parts of code taken from sndcal library by Scott E. Lee:
+//
+// Copyright 1993-1995, Scott E. Lee, all rights reserved.
+// Permission granted to use, copy, modify, distribute and sell
+// so long as the above copyright and this permission statement
+// are retained in all copies.
+//
// Licence: wxWindows license
-/////////////////////////////////////////////////////////////////////////////
+///////////////////////////////////////////////////////////////////////////////
+
+/*
+ * Implementation notes:
+ *
+ * 1. the time is stored as a 64bit integer containing the signed number of
+ * 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
+ *
+ * 3. standard ANSI C functions are used to do time calculations whenever
+ * possible, i.e. when the date is in the range Jan 1, 1970 to 2038
+ *
+ * 4. otherwise, the calculations are done by converting the date to/from JDN
+ * first (the range limitation mentioned above comes from here: the
+ * 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.
+ */
// ============================================================================
// declarations
// constants
// ----------------------------------------------------------------------------
-// note that all these constants should be signed or we'd get some big
-// surprizes with C integer arithmetics
+// some trivial ones
static const int MONTHS_IN_YEAR = 12;
static const int SECONDS_IN_MINUTE = 60;
-// the number of days in month in Julian/Gregorian calendar: the first line is
-// for normal years, the second one is for the leap ones
-static wxDateTime::wxDateTime_t gs_daysInMonth[2][MONTHS_IN_YEAR] =
-{
- { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
- { 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
-};
+static const long SECONDS_PER_DAY = 86400l;
+
+static const long MILLISECONDS_PER_DAY = 86400000l;
+
+// this is the integral part of JDN of the midnight of Jan 1, 1970
+// (i.e. JDN(Jan 1, 1970) = 2440587.5)
+static const int EPOCH_JDN = 2440587;
+
+// the date of JDN -0.5 (as we don't work with fractional parts, this is the
+// reference date for us) is Nov 24, 4714BC
+static const int JDN_0_YEAR = -4713;
+static const int JDN_0_MONTH = wxDateTime::Nov;
+static const int JDN_0_DAY = 24;
+
+// the constants used for JDN calculations
+static const int JDN_OFFSET = 32046;
+static const int DAYS_PER_5_MONTHS = 153;
+static const int DAYS_PER_4_YEARS = 1461;
+static const int DAYS_PER_400_YEARS = 146097;
// ----------------------------------------------------------------------------
// globals
static inline
wxDateTime::wxDateTime_t GetNumOfDaysInMonth(int year, wxDateTime::Month month)
{
- return gs_daysInMonth[wxDateTime::IsLeapYear(year)][month];
+ // the number of days in month in Julian/Gregorian calendar: the first line
+ // is for normal years, the second one is for the leap ones
+ static wxDateTime::wxDateTime_t daysInMonth[2][MONTHS_IN_YEAR] =
+ {
+ { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
+ { 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
+ };
+
+ return daysInMonth[wxDateTime::IsLeapYear(year)][month];
}
// ensure that the timezone variable is set by calling localtime
if ( !s_timezoneSet )
{
- (void)localtime(0);
+ // just call localtime() instead of figuring out whether this system
+ // supports tzset(), _tzset() or something else
+ time_t t;
+ (void)localtime(&t);
s_timezoneSet = TRUE;
}
return (int)timezone;
}
+// return the integral part of the JDN for the midnight of the given date (to
+// get the real JDN you need to add 0.5, this is, in fact, JDN of the
+// noon of the previous day)
+static long GetTruncatedJDN(wxDateTime::wxDateTime_t day,
+ wxDateTime::Month mon,
+ int year)
+{
+ // CREDIT: code below is by Scott E. Lee (but bugs are mine)
+
+ // check the date validity
+ wxASSERT_MSG(
+ (year > JDN_0_YEAR) ||
+ ((year == JDN_0_YEAR) && (mon > JDN_0_MONTH)) ||
+ ((year == JDN_0_YEAR) && (mon == JDN_0_MONTH) && (day >= JDN_0_DAY)),
+ _T("date out of range - can't convert to JDN")
+ );
+
+ // make the year positive to avoid problems with negative numbers division
+ year += 4800;
+
+ // months are counted from March here
+ int month;
+ if ( mon >= wxDateTime::Mar )
+ {
+ month = mon - 2;
+ }
+ else
+ {
+ month = mon + 10;
+ year--;
+ }
+
+ // now we can simply add all the contributions together
+ return ((year / 100) * DAYS_PER_400_YEARS) / 4
+ + ((year % 100) * DAYS_PER_4_YEARS) / 4
+ + (month * DAYS_PER_5_MONTHS + 2) / 5
+ + day
+ - JDN_OFFSET;
+}
+
// this function is a wrapper around strftime(3)
static wxString CallStrftime(const wxChar *format, const tm* tm)
{
year = (wxDateTime_t)wxDateTime::Inv_Year;
mon = wxDateTime::Inv_Month;
mday = 0;
- hour = min = sec = 0;
+ hour = min = sec = msec = 0;
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;
min = tm.tm_min;
hour = tm.tm_hour;
// 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)) &&
- (hour < 24) && (min < 60) && (sec < 62);
+ (hour < 24) && (min < 60) && (sec < 62) && (msec < 1000);
}
void wxDateTime::Tm::ComputeWeekDay()
wxFAIL_MSG(_T("TODO"));
}
-void wxDateTime::Tm::AddMonths(wxDateTime::wxDateTime_t monDiff)
+void wxDateTime::Tm::AddMonths(int monDiff)
{
// normalize the months field
while ( monDiff < -mon )
mon = (wxDateTime::Month)(mon + monDiff);
- wxASSERT_MSG( mon >= 0 && mon < 12, _T("logic error") );
+ wxASSERT_MSG( mon >= 0 && mon < MONTHS_IN_YEAR, _T("logic error") );
}
-void wxDateTime::Tm::AddDays(wxDateTime::wxDateTime_t dayDiff)
+void wxDateTime::Tm::AddDays(int dayDiff)
{
// normalize the days field
mday += dayDiff;
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:
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:
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:
// take some arbitrary Sunday
tm tm = { 0, 0, 0, 28, Nov, 99 };
- // and offset it by the number of days needed to get
+ // and offset it by the number of days needed to get the correct wday
tm.tm_mday += wday;
return CallStrftime(abbr ? _T("%a") : _T("%A"), &tm);
// 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);
+ struct tm tm2(tm);
time_t timet = mktime(&tm2);
- if ( timet == (time_t)(-1) )
+
+ if ( timet == (time_t)-1 )
{
- wxFAIL_MSG(_T("Invalid time"));
+ // mktime() rather unintuitively fails for Jan 1, 1970 if the hour is
+ // less than timezone - try to make it work for this case
+ if ( tm2.tm_year == 70 && tm2.tm_mon == 0 && tm2.tm_mday == 1 )
+ {
+ // add timezone to make sure that date is in range
+ tm2.tm_sec -= GetTimeZone();
+
+ timet = mktime(&tm2);
+ if ( timet != (time_t)-1 )
+ {
+ timet += GetTimeZone();
+
+ return Set(timet);
+ }
+ }
+
+ wxFAIL_MSG( _T("mktime() failed") );
return ms_InvDateTime;
}
time_t timet = GetTimeNow();
struct tm *tm = localtime(&timet);
+ wxCHECK_MSG( tm, ms_InvDateTime, _T("localtime() failed") );
+
// adjust the time
tm->tm_hour = hour;
tm->tm_min = minute;
ReplaceDefaultYearMonthWithCurrent(&year, &month);
- wxCHECK_MSG( day <= GetNumberOfDays(month, year), ms_InvDateTime,
+ wxCHECK_MSG( (0 < day) && (day <= GetNumberOfDays(month, year)),
+ ms_InvDateTime,
_T("Invalid date in wxDateTime::Set()") );
// the range of time_t type (inclusive)
tm.tm_hour = hour;
tm.tm_min = minute;
tm.tm_sec = second;
+ tm.tm_isdst = -1; // mktime() will guess it
(void)Set(tm);
{
// do time calculations ourselves: we want to calculate the number of
// milliseconds between the given date and the epoch
- wxFAIL_MSG(_T("TODO"));
+
+ // get the JDN for the midnight of this day
+ m_time = GetTruncatedJDN(day, month, year);
+ m_time -= EPOCH_JDN;
+ m_time *= SECONDS_PER_DAY * TIME_T_FACTOR;
+
+ // JDN corresponds to GMT, we take localtime
+ Add(wxTimeSpan(hour, minute, second + GetTimeZone(), millisec));
}
return *this;
}
+wxDateTime& wxDateTime::Set(double jdn)
+{
+ // so that m_time will be 0 for the midnight of Jan 1, 1970 which is jdn
+ // EPOCH_JDN + 0.5
+ jdn -= EPOCH_JDN + 0.5;
+
+ m_time = jdn;
+ m_time *= MILLISECONDS_PER_DAY;
+
+ return *this;
+}
+
// ----------------------------------------------------------------------------
// 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") );
if ( time != (time_t)-1 )
{
// use C RTL functions
- tm *tm = localtime(&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, Tm(), _T("localtime() failed") );
+ wxCHECK_MSG( tm, Tm(), _T("gmtime() failed") );
- return Tm(*tm);
+ return Tm(*tm, tz);
}
else
{
- wxFAIL_MSG(_T("TODO"));
+ // 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;
+
+ 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;
+ }
+
+ timeMidnight -= timeOnly;
+
+ // calculate the Gregorian date from JDN for the midnight of our date:
+ // this will yield day, month (in 1..12 range) and year
+
+ // actually, this is the JDN for the noon of the previous day
+ long jdn = (timeMidnight / MILLISECONDS_PER_DAY).ToLong() + EPOCH_JDN;
+
+ // CREDIT: code below is by Scott E. Lee (but bugs are mine)
+
+ wxASSERT_MSG( jdn > -2, _T("JDN out of range") );
+
+ // calculate the century
+ int temp = (jdn + JDN_OFFSET) * 4 - 1;
+ int century = temp / DAYS_PER_400_YEARS;
+
+ // 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;
+
+ // 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;
+
+ // month is counted from March - convert to normal
+ if ( month < 10 )
+ {
+ month += 3;
+ }
+ else
+ {
+ year += 1;
+ month -= 9;
+ }
+
+ // year is offset by 4800
+ year -= 4800;
+
+ // 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") );
+
+ // 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.sec = timeOnly % 60;
+ timeOnly -= tm.sec;
+ timeOnly /= 60; // now we have time in minutes
- return Tm();
+ tm.min = timeOnly % 60;
+ timeOnly -= tm.min;
+
+ tm.hour = timeOnly / 60;
+
+ return tm;
}
}
}
// ----------------------------------------------------------------------------
-// timezone stuff
+// Julian day number conversion and related stuff
// ----------------------------------------------------------------------------
-wxDateTime& wxDateTime::MakeUTC()
+double wxDateTime::GetJulianDayNumber() const
{
- return Add(wxTimeSpan::Seconds(GetTimeZone()));
+ // JDN are always expressed for the GMT dates
+ Tm tm(ToTimezone(GMT0).GetTm(GMT0));
+
+ double result = GetTruncatedJDN(tm.mday, tm.mon, tm.year);
+
+ // add the part GetTruncatedJDN() neglected
+ result += 0.5;
+
+ // and now add the time: 86400 sec = 1 JDN
+ return result + ((double)(60*(60*tm.hour + tm.min) + tm.sec)) / 86400;
}
-wxDateTime& wxDateTime::MakeTimezone(const TimeZone& tz)
+double wxDateTime::GetRataDie() const
{
- int minDiff = GetTimeZone() / SECONDS_IN_MINUTE + tz.GetOffset();
- return Add(wxTimeSpan::Minutes(minDiff));
+ // March 1 of the year 0 is Rata Die day -306 and JDN 1721119.5
+ return GetJulianDayNumber() - 1721119.5 - 306;
+}
+
+// ----------------------------------------------------------------------------
+// timezone and DST stuff
+// ----------------------------------------------------------------------------
+
+int wxDateTime::IsDST(wxDateTime::Country country) const
+{
+ 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::MakeLocalTime(const TimeZone& tz)
+wxDateTime& wxDateTime::MakeTimezone(const TimeZone& tz)
{
- int minDiff = GetTimeZone() / SECONDS_IN_MINUTE + tz.GetOffset();
- return Substract(wxTimeSpan::Minutes(minDiff));
+ int secDiff = GetTimeZone() + tz.GetOffset();
+
+ // 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") );
+
time_t time = GetTicks();
if ( time != (time_t)-1 )
{
// use strftime()
- tm *tm = localtime(&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("localtime() failed") );
+ wxCHECK_MSG( tm, _T(""), _T("gmtime() failed") );
return CallStrftime(format, tm);
}
else
{
- wxFAIL_MSG(_T("TODO"));
+ // 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 )
+ {
+ replacement << (wxChar)-1;
+ }
+
+ // replace all occurences of year with it
+ bool wasReplaced = fmt.Replace(strYear, replacement) > 0;
+
+ // use strftime() to format the same date but in supported year
+ wxDateTime dt(*this);
+ dt.SetYear(year);
+ wxString str = dt.Format(format, tz);
- return _T("");
+ // now replace the occurence of 1999 with the real year
+ wxString strYearReal;
+ strYearReal.Printf(_T("%d"), yearReal);
+ str.Replace(strYear, strYearReal);
+
+ // and replace back all occurences of replacement string
+ if ( wasReplaced )
+ str.Replace(replacement, strYear);
+
+ return str;
}
}
// wxTimeSpan
// ============================================================================
+// not all strftime(3) format specifiers make sense here because, for example,
+// a time span doesn't have a year nor a timezone
+//
+// Here are the ones which are supported (all of them are supported by strftime
+// as well):
+// %H hour in 24 hour format
+// %M minute (00 - 59)
+// %S second (00 - 59)
+// %% percent sign
+//
+// Also, for MFC CTimeSpan compatibility, we support
+// %D number of days
+//
+// And, to be better than MFC :-), we also have
+// %E number of wEeks
+// %l milliseconds (000 - 999)
wxString wxTimeSpan::Format(const wxChar *format) const
{
- wxFAIL_MSG( _T("TODO") );
+ wxCHECK_MSG( format, _T(""), _T("NULL format in wxTimeSpan::Format") );
wxString str;
+ str.Alloc(strlen(format));
+
+ for ( const wxChar *pch = format; pch; pch++ )
+ {
+ wxChar ch = *pch;
+
+ if ( ch == '%' )
+ {
+ wxString tmp;
+
+ ch = *pch++;
+ switch ( ch )
+ {
+ default:
+ wxFAIL_MSG( _T("invalid format character") );
+ // fall through
+
+ case '%':
+ // will get to str << ch below
+ break;
+
+ case 'D':
+ tmp.Printf(_T("%d"), GetDays());
+ break;
+
+ case 'E':
+ tmp.Printf(_T("%d"), GetWeeks());
+ break;
+
+ case 'H':
+ tmp.Printf(_T("%02d"), GetHours());
+ break;
+
+ case 'l':
+ tmp.Printf(_T("%03d"), GetMilliseconds());
+ break;
+
+ case 'M':
+ tmp.Printf(_T("%02d"), GetMinutes());
+ break;
+
+ case 'S':
+ tmp.Printf(_T("%02d"), GetSeconds());
+ break;
+ }
+
+ if ( !!tmp )
+ {
+ str += tmp;
+
+ // skip str += ch below
+ continue;
+ }
+ }
+
+ str += ch;
+ }
return str;
}
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