X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/e6ec579c77012dd0ff1e16b2385e2d3ccf1b911b..5ea6dbbfff67d1dfad08044ab721ba56425ef6e1:/src/common/datetime.cpp diff --git a/src/common/datetime.cpp b/src/common/datetime.cpp index 09215a7592..93c8dc6b84 100644 --- a/src/common/datetime.cpp +++ b/src/common/datetime.cpp @@ -1,13 +1,48 @@ -///////////////////////////////////////////////////////////////////////////// +/////////////////////////////////////////////////////////////////////////////// // 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 +// Copyright: (c) 1999 Vadim Zeitlin +// 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 @@ -40,6 +75,10 @@ #include "wx/datetime.h" +#ifndef WX_TIMEZONE + #define WX_TIMEZONE timezone +#endif + // ---------------------------------------------------------------------------- // constants // ---------------------------------------------------------------------------- @@ -57,6 +96,18 @@ static const long MILLISECONDS_PER_DAY = 86400000l; // (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 // ---------------------------------------------------------------------------- @@ -96,7 +147,7 @@ static int GetTimeZone() if ( !s_timezoneSet ) { - // just call localtime() instead of figurin out whether this system + // just call localtime() instead of figuring out whether this system // supports tzset(), _tzset() or something else time_t t; (void)localtime(&t); @@ -104,47 +155,47 @@ static int GetTimeZone() s_timezoneSet = TRUE; } - return (int)timezone; + return (int)WX_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) +// 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: the algorithm was taken from Peter Baum's home page - - // the algorithm assumes Jan == 1 - int month = mon + 1; - - // we want the leap day (Feb 29) be at the end of the year, so we count - // March as the first month - if ( month < wxDateTime::Mar + 1 ) + // 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 += MONTHS_IN_YEAR; - year--; + month = mon - 2; } - - // this table contains the number of the days before the 1st of the each - // month (in a non leap year) with the third value corresponding to March - // (and the last one to February) - static const int monthOffsets[14] = + else { - 0, 31, 61, 92, 122, 153, 184, 214, 245, 275, 306 - }; + month = mon + 10; + year--; + } - // and now add contributions of all terms together to get the result (you'd - // better see the Web page for the description if you want to understand - // why it works (if it does :-)) - return day + - // linear approximation for months - monthOffsets[month - (wxDateTime::Mar + 1)] + - // the year contribution - 365*year + year/4 - year/100 + year/400 + - // 1721119.5 is the JDN of the midnight of Mar 1, year 0 - 1721118; + // 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) @@ -206,7 +257,8 @@ 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; @@ -223,13 +275,16 @@ bool wxDateTime::Tm::IsValid() const { // 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) @@ -245,6 +300,8 @@ void wxDateTime::Tm::AddMonths(int monDiff) while ( monDiff + mon > MONTHS_IN_YEAR ) { year++; + + monDiff -= MONTHS_IN_YEAR; } mon = (wxDateTime::Month)(mon + monDiff); @@ -283,7 +340,9 @@ 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: @@ -298,7 +357,7 @@ 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: @@ -314,12 +373,12 @@ 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: @@ -364,12 +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) { @@ -485,25 +538,322 @@ wxString wxDateTime::GetWeekDayName(wxDateTime::WeekDay wday, bool abbr) // 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; + // call mktime() to normalize it... + (void)mktime(&tm); + + // ... and call strftime() 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 // ---------------------------------------------------------------------------- -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; } @@ -530,6 +880,8 @@ wxDateTime& wxDateTime::Set(wxDateTime_t hour, 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; @@ -557,7 +909,8 @@ wxDateTime& wxDateTime::Set(wxDateTime_t day, 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) @@ -577,6 +930,7 @@ 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 (void)Set(tm); @@ -593,7 +947,8 @@ 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; @@ -601,7 +956,12 @@ wxDateTime& wxDateTime::Set(wxDateTime_t day, wxDateTime& wxDateTime::Set(double jdn) { - m_time = (jdn - 0.5 - EPOCH_JDN) * TIME_T_FACTOR; + // 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; } @@ -610,7 +970,7 @@ 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") ); @@ -618,60 +978,117 @@ wxDateTime::Tm wxDateTime::GetTm() const 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); - // should never happen - wxCHECK_MSG( tm, Tm(), _T("localtime() failed") ); + // should never happen + wxCHECK_MSG( tm, Tm(), _T("gmtime() failed") ); + } + else + { + time += tz.GetOffset(); + if ( time >= 0 ) + { + tm = gmtime(&time); - return Tm(*tm); - } - else - { - // CREDIT: the algorithm was taken from Peter Baum's home page - - // calculate the Gregorian date from JDN for the midnight of our date - wxLongLong timeMidnight = m_time; - long timeOnly = (m_time % MILLISECONDS_PER_DAY).GetLo(); - timeMidnight -= timeOnly; - - // TODO this probably could be optimised somehow... - - double jdn = (timeMidnight / MILLISECONDS_PER_DAY).GetLo(); - jdn += EPOCH_JDN + 0.5; - long z = jdn - 1721118.5; - double r = jdn - 1721118.5 - z; - double g = z - 0.25; - long a = g/36524.25; // number of days per year - long b = a - a / 4; - int year = (b + g) / 365.25; - long c = b + z - 365.25*year; - int month = (5*c + 456)/153; - int day = c - (153*month - 457)/5 + (r < 0.5 ? 0 : 1); - if ( month > 12 ) + // should never happen + wxCHECK_MSG( tm, Tm(), _T("gmtime() failed") ); + } + else + { + tm = (struct tm *)NULL; + } + } + + if ( tm ) { - year++; - month -= 12; + return Tm(*tm, tz); } + //else: use generic code below + } + + // 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; - Tm tm; - tm.year = year; - tm.mon = (Month)(month - 1); // algorithm yields 1 for January, not 0 - tm.mday = day; - tm.msec = timeOnly % 1000; - timeOnly -= tm.msec; - timeOnly /= 1000; // now we have time in seconds + // CREDIT: code below is by Scott E. Lee (but bugs are mine) - tm.sec = timeOnly % 60; - timeOnly -= tm.sec; - timeOnly /= 60; // now we have time in minutes + wxASSERT_MSG( jdn > -2, _T("JDN out of range") ); - tm.min = timeOnly % 60; - timeOnly -= tm.min; + // calculate the century + int temp = (jdn + JDN_OFFSET) * 4 - 1; + int century = temp / DAYS_PER_400_YEARS; - tm.hour = timeOnly / 60; + // 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; - return tm; + // 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 + + tm.min = timeOnly % 60; + timeOnly -= tm.min; + + tm.hour = timeOnly / 60; + + return tm; } wxDateTime& wxDateTime::SetYear(int year) @@ -814,9 +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); @@ -830,7 +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); } @@ -849,13 +1266,54 @@ 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 // ---------------------------------------------------------------------------- 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); @@ -873,31 +1331,57 @@ 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 + { + int year = GetYear(); + + if ( !IsDSTApplicable(year, country) ) + { + // no DST time in this year in this country + return -1; + } + + return IsBetween(GetBeginDST(year, country), GetEndDST(year, country)); + } } 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") ); @@ -905,58 +1389,116 @@ wxString wxDateTime::Format(const wxChar *format) const 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); - // should never happen - wxCHECK_MSG( tm, _T(""), _T("localtime() failed") ); + // should never happen + wxCHECK_MSG( tm, wxEmptyString, _T("localtime() failed") ); + } + else + { + time += tz.GetOffset(); - 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(); - 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 ( time >= 0 ) + { + tm = gmtime(&time); + + // should never happen + wxCHECK_MSG( tm, wxEmptyString, _T("gmtime() failed") ); + } + else + { + tm = (struct tm *)NULL; + } + } + + 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); + // 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; } // ============================================================================ @@ -1018,7 +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': @@ -1026,7 +1568,7 @@ wxString wxTimeSpan::Format(const wxChar *format) const break; case 'S': - tmp.Printf(_T("%02d"), GetSeconds()); + tmp.Printf(_T("%02d"), GetSeconds().GetValue()); break; }