]> git.saurik.com Git - wxWidgets.git/blobdiff - src/common/datetime.cpp
wxLogTrace doesn't give messages with two 'Trace' in the beginning
[wxWidgets.git] / src / common / datetime.cpp
index f254ddc7e502cd071599c28051c262f0b0d40cda..eafbeeb5863cedd1db4bf5f3ddc309b419878eb0 100644 (file)
@@ -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 <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
     #include "wx/log.h"
 #endif // WX_PRECOMP
 
-#define wxDEFINE_TIME_CONSTANTS
+#include "wx/thread.h"
+#include "wx/tokenzr.h"
+#include "wx/module.h"
+
+#define wxDEFINE_TIME_CONSTANTS // before including datetime.h
+
+#include <ctype.h>
 
 #include "wx/datetime.h"
 
+// ----------------------------------------------------------------------------
+// conditional compilation
+// ----------------------------------------------------------------------------
+
+#if defined(HAVE_STRPTIME) && defined(__LINUX__)
+    // glibc 2.0.7 strptime() is broken - the following snippet causes it to
+    // crash (instead of just failing):
+    //
+    //      strncpy(buf, "Tue Dec 21 20:25:40 1999", 128);
+    //      strptime(buf, "%x", &tm);
+    //
+    // so don't use it
+    #undef HAVE_STRPTIME
+#endif // broken strptime()
+
+#ifndef WX_TIMEZONE
+    #if defined(__BORLANDC__) || defined(__MINGW32__) || defined(__VISAGECPP__)
+        #define WX_TIMEZONE _timezone
+    #elif defined(__MWERKS__)
+       long wxmw_timezone = 28800;
+       #define WX_TIMEZONE wxmw_timezone ;
+    #else // unknown platform - try timezone
+        #define WX_TIMEZONE timezone
+    #endif
+#endif // !WX_TIMEZONE
+
+// ----------------------------------------------------------------------------
+// private classes
+// ----------------------------------------------------------------------------
+
+class wxDateTimeHolidaysModule : public wxModule
+{
+public:
+    virtual bool OnInit()
+    {
+        wxDateTimeHolidayAuthority::AddAuthority(new wxDateTimeWorkDays);
+
+        return TRUE;
+    }
+
+    virtual void OnExit()
+    {
+        wxDateTimeHolidayAuthority::ClearAllAuthorities();
+        wxDateTimeHolidayAuthority::ms_authorities.Clear();
+    }
+
+private:
+    DECLARE_DYNAMIC_CLASS(wxDateTimeHolidaysModule)
+};
+
+IMPLEMENT_DYNAMIC_CLASS(wxDateTimeHolidaysModule, wxModule)
+
 // ----------------------------------------------------------------------------
 // constants
 // ----------------------------------------------------------------------------
 
-// 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][12] =
+// some trivial ones
+static const int MONTHS_IN_YEAR = 12;
+
+static const int SECONDS_IN_MINUTE = 60;
+
+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 long EPOCH_JDN = 2440587l;
+
+// 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 long JDN_OFFSET         = 32046l;
+static const long DAYS_PER_5_MONTHS  = 153l;
+static const long DAYS_PER_4_YEARS   = 1461l;
+static const long DAYS_PER_400_YEARS = 146097l;
+
+// this array contains the cumulated number of days in all previous months for
+// normal and leap years
+static const wxDateTime::wxDateTime_t gs_cumulatedDays[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 }
+    { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 },
+    { 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335 }
 };
 
+// ----------------------------------------------------------------------------
+// global data
+// ----------------------------------------------------------------------------
+
+static wxDateTime gs_dtDefault;
+
+wxDateTime& wxDefaultDateTime = gs_dtDefault;
+
+wxDateTime::Country wxDateTime::ms_country = wxDateTime::Country_Unknown;
+
+// ----------------------------------------------------------------------------
+// private globals
+// ----------------------------------------------------------------------------
+
+// a critical section is needed to protect GetTimeZone() static
+// variable in MT case
+#if wxUSE_THREADS
+    static wxCriticalSection gs_critsectTimezone;
+#endif // wxUSE_THREADS
+
 // ----------------------------------------------------------------------------
 // private functions
 // ----------------------------------------------------------------------------
 
+// debugger helper: shows what the date really is
+#ifdef __WXDEBUG__
+extern const wxChar *wxDumpDate(const wxDateTime* dt)
+{
+    static wxChar buf[128];
+
+    wxStrcpy(buf, dt->Format(_T("%Y-%m-%d (%a) %H:%M:%S")));
+
+    return buf;
+}
+#endif // Debug
+
+// get the number of days in the given month of the given year
+static inline
+wxDateTime::wxDateTime_t GetNumOfDaysInMonth(int year, wxDateTime::Month 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
+static int GetTimeZone()
+{
+    // set to TRUE when the timezone is set
+    static bool s_timezoneSet = FALSE;
+
+    wxCRIT_SECT_LOCKER(lock, gs_critsectTimezone);
+
+    if ( !s_timezoneSet )
+    {
+        // 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)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)
+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)
 {
-    wxChar buf[1024];
+    wxChar buf[4096];
     if ( !wxStrftime(buf, WXSIZEOF(buf), format, tm) )
     {
-        // is ti really possible that 1024 is too short?
+        // buffer is too small?
         wxFAIL_MSG(_T("strftime() failed"));
     }
 
     return wxString(buf);
 }
 
+// if year and/or month have invalid values, replace them with the current ones
+static void ReplaceDefaultYearMonthWithCurrent(int *year,
+                                               wxDateTime::Month *month)
+{
+    struct tm *tmNow = NULL;
+
+    if ( *year == wxDateTime::Inv_Year )
+    {
+        tmNow = wxDateTime::GetTmNow();
+
+        *year = 1900 + tmNow->tm_year;
+    }
+
+    if ( *month == wxDateTime::Inv_Month )
+    {
+        if ( !tmNow )
+            tmNow = wxDateTime::GetTmNow();
+
+        *month = (wxDateTime::Month)tmNow->tm_mon;
+    }
+}
+
+// fll the struct tm with default values
+static void InitTm(struct tm& tm)
+{
+    // struct tm may have etxra fields (undocumented and with unportable
+    // names) which, nevertheless, must be set to 0
+    memset(&tm, 0, sizeof(struct tm));
+
+    tm.tm_mday = 1;   // mday 0 is invalid
+    tm.tm_year = 76;  // any valid year
+    tm.tm_isdst = -1; // auto determine
+}
+
+// parsing helpers
+// ---------------
+
+// return the month if the string is a month name or Inv_Month otherwise
+static wxDateTime::Month GetMonthFromName(const wxString& name, int flags)
+{
+    wxDateTime::Month mon;
+    for ( mon = wxDateTime::Jan; mon < wxDateTime::Inv_Month; wxNextMonth(mon) )
+    {
+        // case-insensitive comparison either one of or with both abbreviated
+        // and not versions
+        if ( flags & wxDateTime::Name_Full )
+        {
+            if ( name.CmpNoCase(wxDateTime::
+                        GetMonthName(mon, wxDateTime::Name_Full)) == 0 )
+            {
+                break;
+            }
+        }
+
+        if ( flags & wxDateTime::Name_Abbr )
+        {
+            if ( name.CmpNoCase(wxDateTime::
+                        GetMonthName(mon, wxDateTime::Name_Abbr)) == 0 )
+            {
+                break;
+            }
+        }
+    }
+
+    return mon;
+}
+
+// return the weekday if the string is a weekday name or Inv_WeekDay otherwise
+static wxDateTime::WeekDay GetWeekDayFromName(const wxString& name, int flags)
+{
+    wxDateTime::WeekDay wd;
+    for ( wd = wxDateTime::Sun; wd < wxDateTime::Inv_WeekDay; wxNextWDay(wd) )
+    {
+        // case-insensitive comparison either one of or with both abbreviated
+        // and not versions
+        if ( flags & wxDateTime::Name_Full )
+        {
+            if ( name.CmpNoCase(wxDateTime::
+                        GetWeekDayName(wd, wxDateTime::Name_Full)) == 0 )
+            {
+                break;
+            }
+        }
+
+        if ( flags & wxDateTime::Name_Abbr )
+        {
+            if ( name.CmpNoCase(wxDateTime::
+                        GetWeekDayName(wd, wxDateTime::Name_Abbr)) == 0 )
+            {
+                break;
+            }
+        }
+    }
+
+    return wd;
+}
+
+// scans all digits and returns the resulting number
+static bool GetNumericToken(const wxChar*& p, unsigned long *number)
+{
+    wxString s;
+    while ( wxIsdigit(*p) )
+    {
+        s += *p++;
+    }
+
+    return !!s && s.ToULong(number);
+}
+
+// scans all alphabetic characters and returns the resulting string
+static wxString GetAlphaToken(const wxChar*& p)
+{
+    wxString s;
+    while ( wxIsalpha(*p) )
+    {
+        s += *p++;
+    }
+
+    return s;
+}
+
 // ============================================================================
 // implementation of wxDateTime
 // ============================================================================
 
-// ----------------------------------------------------------------------------
-// static data
-// ----------------------------------------------------------------------------
-
-wxDateTime::Country wxDateTime::ms_country = wxDateTime::Country_Unknown;
-wxDateTime wxDateTime::ms_InvDateTime;
-
 // ----------------------------------------------------------------------------
 // struct Tm
 // ----------------------------------------------------------------------------
@@ -86,17 +427,19 @@ wxDateTime::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;
     mday = tm.tm_mday;
-    mon = tm.tm_mon;
+    mon = (wxDateTime::Month)tm.tm_mon;
     year = 1900 + tm.tm_year;
     wday = tm.tm_wday;
     yday = tm.tm_yday;
@@ -105,14 +448,119 @@ wxDateTime::Tm::Tm(const struct tm& tm)
 bool wxDateTime::Tm::IsValid() const
 {
     // we allow for the leap seconds, although we don't use them (yet)
-    return (year != wxDateTime::Inv_Year) && (mon < 12) &&
-           (mday < gs_daysInMonth[IsLeapYear(year)][mon]) &&
-           (hour < 24) && (min < 60) && (sec < 62);
+    return (year != wxDateTime::Inv_Year) && (mon != wxDateTime::Inv_Month) &&
+           (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)
+{
+    // normalize the months field
+    while ( monDiff < -mon )
+    {
+        year--;
+
+        monDiff += MONTHS_IN_YEAR;
+    }
+
+    while ( monDiff + mon >= MONTHS_IN_YEAR )
+    {
+        year++;
+
+        monDiff -= MONTHS_IN_YEAR;
+    }
+
+    mon = (wxDateTime::Month)(mon + monDiff);
+
+    wxASSERT_MSG( mon >= 0 && mon < MONTHS_IN_YEAR, _T("logic error") );
+
+    // NB: we don't check here that the resulting date is valid, this function
+    //     is private and the caller must check it if needed
+}
+
+void wxDateTime::Tm::AddDays(int dayDiff)
+{
+    // normalize the days field
+    while ( dayDiff + mday < 1 )
+    {
+        AddMonths(-1);
+
+        dayDiff += GetNumOfDaysInMonth(year, mon);
+    }
+
+    mday += dayDiff;
+    while ( mday > GetNumOfDaysInMonth(year, mon) )
+    {
+        mday -= GetNumOfDaysInMonth(year, mon);
+
+        AddMonths(1);
+    }
+
+    wxASSERT_MSG( mday > 0 && mday <= GetNumOfDaysInMonth(year, mon),
+                  _T("logic error") );
+}
+
+// ----------------------------------------------------------------------------
+// class TimeZone
+// ----------------------------------------------------------------------------
+
+wxDateTime::TimeZone::TimeZone(wxDateTime::TZ tz)
+{
+    switch ( tz )
+    {
+        case wxDateTime::Local:
+            // 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_11:
+        case wxDateTime::GMT_10:
+        case wxDateTime::GMT_9:
+        case wxDateTime::GMT_8:
+        case wxDateTime::GMT_7:
+        case wxDateTime::GMT_6:
+        case wxDateTime::GMT_5:
+        case wxDateTime::GMT_4:
+        case wxDateTime::GMT_3:
+        case wxDateTime::GMT_2:
+        case wxDateTime::GMT_1:
+            m_offset = -3600*(wxDateTime::GMT0 - tz);
+            break;
+
+        case wxDateTime::GMT0:
+        case wxDateTime::GMT1:
+        case wxDateTime::GMT2:
+        case wxDateTime::GMT3:
+        case wxDateTime::GMT4:
+        case wxDateTime::GMT5:
+        case wxDateTime::GMT6:
+        case wxDateTime::GMT7:
+        case wxDateTime::GMT8:
+        case wxDateTime::GMT9:
+        case wxDateTime::GMT10:
+        case wxDateTime::GMT11:
+        case wxDateTime::GMT12:
+            m_offset = 3600*(tz - wxDateTime::GMT0);
+            break;
+
+        case wxDateTime::A_CST:
+            // Central Standard Time in use in Australia = UTC + 9.5
+            m_offset = 60l*(9*60 + 30);
+            break;
+
+        default:
+            wxFAIL_MSG( _T("unknown time zone") );
+    }
 }
 
 // ----------------------------------------------------------------------------
@@ -122,6 +570,9 @@ void wxDateTime::Tm::ComputeWeekDay()
 /* static */
 bool wxDateTime::IsLeapYear(int year, wxDateTime::Calendar cal)
 {
+    if ( year == Inv_Year )
+        year = GetCurrentYear();
+
     if ( cal == Gregorian )
     {
         // in Gregorian calendar leap years are those divisible by 4 except
@@ -144,9 +595,9 @@ bool wxDateTime::IsLeapYear(int year, wxDateTime::Calendar cal)
 }
 
 /* static */
-void wxDateTime::SetCountry(wxDateTime::Country country)
+int wxDateTime::GetCentury(int year)
 {
-    ms_country = country;
+    return year > 0 ? year / 100 : year / 100 - 1;
 }
 
 /* static */
@@ -183,7 +634,6 @@ wxDateTime::Month wxDateTime::GetCurrentMonth(wxDateTime::Calendar cal)
     {
         case Gregorian:
             return Now().GetMonth();
-            break;
 
         case Julian:
             wxFAIL_MSG(_T("TODO"));
@@ -197,12 +647,35 @@ wxDateTime::Month wxDateTime::GetCurrentMonth(wxDateTime::Calendar cal)
     return Inv_Month;
 }
 
+/* static */
+wxDateTime::wxDateTime_t wxDateTime::GetNumberOfDays(int year, Calendar cal)
+{
+    if ( year == Inv_Year )
+    {
+        // take the current year if none given
+        year = GetCurrentYear();
+    }
+
+    switch ( cal )
+    {
+        case Gregorian:
+        case Julian:
+            return IsLeapYear(year) ? 366 : 365;
+
+        default:
+            wxFAIL_MSG(_T("unsupported calendar"));
+            break;
+    }
+
+    return 0;
+}
+
 /* static */
 wxDateTime::wxDateTime_t wxDateTime::GetNumberOfDays(wxDateTime::Month month,
                                                      int year,
                                                      wxDateTime::Calendar cal)
 {
-    wxCHECK_MSG( month < 12, 0, _T("invalid month") );
+    wxCHECK_MSG( month < MONTHS_IN_YEAR, 0, _T("invalid month") );
 
     if ( cal == Gregorian || cal == Julian )
     {
@@ -212,7 +685,7 @@ wxDateTime::wxDateTime_t wxDateTime::GetNumberOfDays(wxDateTime::Month month,
             year = GetCurrentYear();
         }
 
-        return gs_daysInMonth[IsLeapYear(year)][month];
+        return GetNumOfDaysInMonth(year, month);
     }
     else
     {
@@ -223,99 +696,425 @@ wxDateTime::wxDateTime_t wxDateTime::GetNumberOfDays(wxDateTime::Month month,
 }
 
 /* static */
-wxString wxDateTime::GetMonthName(wxDateTime::Month month, bool abbr)
+wxString wxDateTime::GetMonthName(wxDateTime::Month month,
+                                  wxDateTime::NameFlags flags)
 {
     wxCHECK_MSG( month != Inv_Month, _T(""), _T("invalid month") );
 
-    tm tm = { 0, 0, 0, 1, month, 76 };  // any year will do
+    // notice that we must set all the fields to avoid confusing libc (GNU one
+    // gets confused to a crash if we don't do this)
+    tm tm;
+    InitTm(tm);
+    tm.tm_mon = month;
 
-    return CallStrftime(abbr ? _T("%b") : _T("%B"), &tm);
+    return CallStrftime(flags == Name_Abbr ? _T("%b") : _T("%B"), &tm);
 }
 
 /* static */
-wxString wxDateTime::GetWeekDayName(wxDateTime::WeekDay wday, bool abbr)
+wxString wxDateTime::GetWeekDayName(wxDateTime::WeekDay wday,
+                                    wxDateTime::NameFlags flags)
 {
     wxCHECK_MSG( wday != Inv_WeekDay, _T(""), _T("invalid weekday") );
 
     // take some arbitrary Sunday
-    tm tm = { 0, 0, 0, 28, Nov, 99 };
+    tm tm;
+    InitTm(tm);
+    tm.tm_mday = 28;
+    tm.tm_mon = Nov;
+    tm.tm_year = 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);
-}
+    // call mktime() to normalize it...
+    (void)mktime(&tm);
 
-// ----------------------------------------------------------------------------
-// constructors and assignment operators
-// ----------------------------------------------------------------------------
+    // ... and call strftime()
+    return CallStrftime(flags == Name_Abbr ? _T("%a") : _T("%A"), &tm);
+}
 
-wxDateTime& wxDateTime::Set(const struct tm& tm1)
+/* static */
+void wxDateTime::GetAmPmStrings(wxString *am, wxString *pm)
 {
-    wxASSERT_MSG( IsValid(), _T("invalid wxDateTime") );
-
-    tm tm2(tm1);
-    time_t timet = mktime(&tm2);
-    if ( timet == (time_t)(-1) )
+    tm tm;
+    InitTm(tm);
+    if ( am )
     {
-        wxFAIL_MSG(_T("Invalid time"));
-
-        return ms_InvDateTime;
+        *am = CallStrftime(_T("%p"), &tm);
     }
-    else
+    if ( pm )
     {
-        return Set(timet);
+        tm.tm_hour = 13;
+        *pm = CallStrftime(_T("%p"), &tm);
     }
 }
 
-wxDateTime& wxDateTime::Set(wxDateTime_t hour,
-                            wxDateTime_t minute,
-                            wxDateTime_t second,
-                            wxDateTime_t millisec)
-{
-    wxASSERT_MSG( IsValid(), _T("invalid wxDateTime") );
+// ----------------------------------------------------------------------------
+// Country stuff: date calculations depend on the country (DST, work days,
+// ...), so we need to know which rules to follow.
+// ----------------------------------------------------------------------------
 
-    // we allow seconds to be 61 to account for the leap seconds, even if we
-    // don't use them really
-    wxCHECK_MSG( hour < 24 && second < 62 && minute < 60 && millisec < 1000,
-                 ms_InvDateTime,
-                 _T("Invalid time in wxDateTime::Set()") );
+/* static */
+wxDateTime::Country wxDateTime::GetCountry()
+{
+    // TODO use LOCALE_ICOUNTRY setting under Win32
 
-    // get the current date from system
-    time_t timet = GetTimeNow();
-    struct tm *tm = localtime(&timet);
+    if ( ms_country == Country_Unknown )
+    {
+        // try to guess from the time zone name
+        time_t t = time(NULL);
+        struct tm *tm = localtime(&t);
 
-    // adjust the time
-    tm->tm_hour = hour;
-    tm->tm_min = minute;
-    tm->tm_sec = second;
+        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;
+        }
+    }
 
-    (void)Set(*tm);
+    return ms_country;
+}
 
-    // and finally adjust milliseconds
-    return SetMillisecond(millisec);
+/* static */
+void wxDateTime::SetCountry(wxDateTime::Country country)
+{
+    ms_country = country;
 }
 
-wxDateTime& wxDateTime::Set(wxDateTime_t day,
-                            Month        month,
-                            int          year,
-                            wxDateTime_t hour,
-                            wxDateTime_t minute,
-                            wxDateTime_t second,
-                            wxDateTime_t millisec)
+/* static */
+bool wxDateTime::IsWestEuropeanCountry(Country country)
 {
-    wxASSERT_MSG( IsValid(), _T("invalid wxDateTime") );
+    if ( country == Country_Default )
+    {
+        country = GetCountry();
+    }
 
-    wxCHECK_MSG( hour < 24 && second < 62 && minute < 60 && millisec < 1000,
-                 ms_InvDateTime,
-                 _T("Invalid time in wxDateTime::Set()") );
+    return (Country_WesternEurope_Start <= country) &&
+           (country <= Country_WesternEurope_End);
+}
 
-    if ( year == Inv_Year )
-        year = GetCurrentYear();
-    if ( month == Inv_Month )
-        month = GetCurrentMonth();
+// ----------------------------------------------------------------------------
+// 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 wxInvalidDateTime;
+    }
+
+    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);
+
+        // disable DST tests because it could result in an infinite recursion!
+        dt.MakeGMT(TRUE);
+    }
+    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 wxInvalidDateTime;
+    }
+
+    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);
+
+        // disable DST tests because it could result in an infinite recursion!
+        dt.MakeGMT(TRUE);
+    }
+    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
+// ----------------------------------------------------------------------------
+
+// the values in the tm structure contain the local time
+wxDateTime& wxDateTime::Set(const struct tm& tm)
+{
+    wxASSERT_MSG( IsValid(), _T("invalid wxDateTime") );
+
+    struct tm tm2(tm);
+    time_t timet = mktime(&tm2);
+
+    if ( timet == (time_t)-1 )
+    {
+        // 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 wxInvalidDateTime;
+    }
+    else
+    {
+        return Set(timet);
+    }
+}
+
+wxDateTime& wxDateTime::Set(wxDateTime_t hour,
+                            wxDateTime_t minute,
+                            wxDateTime_t second,
+                            wxDateTime_t millisec)
+{
+    wxASSERT_MSG( IsValid(), _T("invalid wxDateTime") );
+
+    // we allow seconds to be 61 to account for the leap seconds, even if we
+    // don't use them really
+    wxCHECK_MSG( hour < 24 && second < 62 && minute < 60 && millisec < 1000,
+                 wxInvalidDateTime,
+                 _T("Invalid time in wxDateTime::Set()") );
+
+    // get the current date from system
+    struct tm *tm = GetTmNow();
+
+    wxCHECK_MSG( tm, wxInvalidDateTime, _T("localtime() failed") );
+
+    // adjust the time
+    tm->tm_hour = hour;
+    tm->tm_min = minute;
+    tm->tm_sec = second;
+
+    (void)Set(*tm);
+
+    // and finally adjust milliseconds
+    return SetMillisecond(millisec);
+}
+
+wxDateTime& wxDateTime::Set(wxDateTime_t day,
+                            Month        month,
+                            int          year,
+                            wxDateTime_t hour,
+                            wxDateTime_t minute,
+                            wxDateTime_t second,
+                            wxDateTime_t millisec)
+{
+    wxASSERT_MSG( IsValid(), _T("invalid wxDateTime") );
+
+    wxCHECK_MSG( hour < 24 && second < 62 && minute < 60 && millisec < 1000,
+                 wxInvalidDateTime,
+                 _T("Invalid time in wxDateTime::Set()") );
+
+    ReplaceDefaultYearMonthWithCurrent(&year, &month);
 
-    wxCHECK_MSG( day < GetNumberOfDays(month, year), ms_InvDateTime,
+    wxCHECK_MSG( (0 < day) && (day <= GetNumberOfDays(month, year)),
+                 wxInvalidDateTime,
                  _T("Invalid date in wxDateTime::Set()") );
 
     // the range of time_t type (inclusive)
@@ -324,7 +1123,7 @@ wxDateTime& wxDateTime::Set(wxDateTime_t day,
 
     // test only the year instead of testing for the exact end of the Unix
     // time_t range - it doesn't bring anything to do more precise checks
-    if ( year >= yearMaxInRange && year <= yearMaxInRange )
+    if ( year >= yearMinInRange && year <= yearMaxInRange )
     {
         // use the standard library version if the date is in range - this is
         // probably more efficient than our code
@@ -335,6 +1134,7 @@ 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);
 
@@ -344,9 +1144,45 @@ wxDateTime& wxDateTime::Set(wxDateTime_t day,
     else
     {
         // do time calculations ourselves: we want to calculate the number of
-        // milliseconds between the given date and the epoch (necessarily
-        // negative)
-        wxFAIL_MSG(_T("TODO"));
+        // milliseconds between the given date and the epoch
+
+        // 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;
+
+    jdn *= MILLISECONDS_PER_DAY;
+
+    m_time.Assign(jdn);
+
+    return *this;
+}
+
+wxDateTime& wxDateTime::ResetTime()
+{
+    Tm tm = GetTm();
+
+    if ( tm.hour || tm.min || tm.sec || tm.msec )
+    {
+        tm.msec =
+        tm.sec =
+        tm.min =
+        tm.hour = 0;
+
+        Set(tm);
     }
 
     return *this;
@@ -356,7 +1192,7 @@ wxDateTime& wxDateTime::Set(wxDateTime_t day,
 // 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") );
 
@@ -364,19 +1200,122 @@ 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("gmtime() failed") );
+        }
+        else
+        {
+            time += (time_t)tz.GetOffset();
+#ifdef __VMS__ // time is unsigned so avoid warning
+            int time2 = (int) time;
+            if ( time2 >= 0 )
+#else
+            if ( time >= 0 )
+#endif
+            {
+                tm = gmtime(&time);
+
+                // should never happen
+                wxCHECK_MSG( tm, Tm(), _T("gmtime() failed") );
+            }
+            else
+            {
+                tm = (struct tm *)NULL;
+            }
+        }
+
+        if ( tm )
+        {
+            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;
+
+    // CREDIT: code below is by Scott E. Lee (but bugs are mine)
 
-        // should never happen
-        wxCHECK_MSG( tm, Tm(), _T("localtime() failed") );
+    wxASSERT_MSG( jdn > -2, _T("JDN out of range") );
 
-        return Tm(*tm);
+    // calculate the century
+    long temp = (jdn + JDN_OFFSET) * 4 - 1;
+    long 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;
+    long year = (century * 100) + (temp / DAYS_PER_4_YEARS);
+    long dayOfYear = (temp % DAYS_PER_4_YEARS) / 4 + 1;
+
+    // and finally the month and day of the month
+    temp = dayOfYear * 5 - 3;
+    long month = temp / DAYS_PER_5_MONTHS;
+    long day = (temp % DAYS_PER_5_MONTHS) / 5 + 1;
+
+    // month is counted from March - convert to normal
+    if ( month < 10 )
+    {
+        month += 3;
     }
     else
     {
-        wxFAIL_MSG(_T("TODO"));
-
-        return Tm();
+        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 = (wxDateTime_t)(timeOnly % 1000);
+    timeOnly -= tm.msec;
+    timeOnly /= 1000;               // now we have time in seconds
+
+    tm.sec = (wxDateTime_t)(timeOnly % 60);
+    timeOnly -= tm.sec;
+    timeOnly /= 60;                 // now we have time in minutes
+
+    tm.min = (wxDateTime_t)(timeOnly % 60);
+    timeOnly -= tm.min;
+
+    tm.hour = (wxDateTime_t)(timeOnly / 60);
+
+    return tm;
 }
 
 wxDateTime& wxDateTime::SetYear(int year)
@@ -465,35 +1404,2151 @@ wxDateTime& wxDateTime::Add(const wxDateSpan& diff)
     Tm tm(GetTm());
 
     tm.year += diff.GetYears();
-    tm.mon += diff.GetMonths();
-    tm.mday += diff.GetTotalDays();
+    tm.AddMonths(diff.GetMonths());
+
+    // check that the resulting date is valid
+    if ( tm.mday > GetNumOfDaysInMonth(tm.year, tm.mon) )
+    {
+        // We suppose that when adding one month to Jan 31 we want to get Feb
+        // 28 (or 29), i.e. adding a month to the last day of the month should
+        // give the last day of the next month which is quite logical.
+        //
+        // Unfortunately, there is no logic way to understand what should
+        // Jan 30 + 1 month be - Feb 28 too or Feb 27 (assuming non leap year)?
+        // We make it Feb 28 (last day too), but it is highly questionable.
+        tm.mday = GetNumOfDaysInMonth(tm.year, tm.mon);
+    }
+
+    tm.AddDays(diff.GetTotalDays());
 
     Set(tm);
 
+    wxASSERT_MSG( IsSameTime(tm),
+                  _T("Add(wxDateSpan) shouldn't modify time") );
+
     return *this;
 }
 
 // ----------------------------------------------------------------------------
-// wxDateTime to/from text representations
+// Weekday and monthday stuff
 // ----------------------------------------------------------------------------
 
-wxString wxDateTime::Format(const wxChar *format) const
+bool wxDateTime::SetToTheWeek(wxDateTime_t numWeek, WeekDay weekday)
 {
-    time_t time = GetTicks();
-    if ( time != (time_t)-1 )
+    int year = GetYear();
+
+    // Jan 4 always lies in the 1st week of the year
+    Set(4, Jan, year);
+    SetToWeekDayInSameWeek(weekday) += wxDateSpan::Weeks(numWeek);
+
+    if ( GetYear() != year )
     {
-        // use strftime()
-        tm *tm = localtime(&time);
+        // oops... numWeek was too big
+        return FALSE;
+    }
+
+    return TRUE;
+}
+
+wxDateTime& wxDateTime::SetToLastMonthDay(Month month,
+                                          int year)
+{
+    // take the current month/year if none specified
+    if ( year == Inv_Year )
+        year = GetYear();
+    if ( month == Inv_Month )
+        month = GetMonth();
+
+    return Set(GetNumOfDaysInMonth(year, month), month, year);
+}
 
-        // should never happen
-        wxCHECK_MSG( tm, _T(""), _T("localtime() failed") );
+wxDateTime& wxDateTime::SetToWeekDayInSameWeek(WeekDay weekday)
+{
+    wxCHECK_MSG( weekday != Inv_WeekDay, wxInvalidDateTime, _T("invalid weekday") );
 
-        return CallStrftime(format, tm);
+    WeekDay wdayThis = GetWeekDay();
+    if ( weekday == wdayThis )
+    {
+        // nothing to do
+        return *this;
     }
-    else
+    else if ( weekday < wdayThis )
+    {
+        return Substract(wxDateSpan::Days(wdayThis - weekday));
+    }
+    else // weekday > wdayThis
+    {
+        return Add(wxDateSpan::Days(weekday - wdayThis));
+    }
+}
+
+wxDateTime& wxDateTime::SetToNextWeekDay(WeekDay weekday)
+{
+    wxCHECK_MSG( weekday != Inv_WeekDay, wxInvalidDateTime, _T("invalid weekday") );
+
+    int diff;
+    WeekDay wdayThis = GetWeekDay();
+    if ( weekday == wdayThis )
+    {
+        // nothing to do
+        return *this;
+    }
+    else if ( weekday < wdayThis )
+    {
+        // need to advance a week
+        diff = 7 - (wdayThis - weekday);
+    }
+    else // weekday > wdayThis
     {
-        wxFAIL_MSG(_T("TODO"));
+        diff = weekday - wdayThis;
+    }
+
+    return Add(wxDateSpan::Days(diff));
+}
+
+wxDateTime& wxDateTime::SetToPrevWeekDay(WeekDay weekday)
+{
+    wxCHECK_MSG( weekday != Inv_WeekDay, wxInvalidDateTime, _T("invalid weekday") );
 
-        return _T("");
+    int diff;
+    WeekDay wdayThis = GetWeekDay();
+    if ( weekday == wdayThis )
+    {
+        // nothing to do
+        return *this;
+    }
+    else if ( weekday > wdayThis )
+    {
+        // need to go to previous week
+        diff = 7 - (weekday - wdayThis);
     }
+    else // weekday < wdayThis
+    {
+        diff = wdayThis - weekday;
+    }
+
+    return Substract(wxDateSpan::Days(diff));
 }
+
+bool wxDateTime::SetToWeekDay(WeekDay weekday,
+                              int n,
+                              Month month,
+                              int year)
+{
+    wxCHECK_MSG( weekday != Inv_WeekDay, FALSE, _T("invalid weekday") );
+
+    // we don't check explicitly that -5 <= n <= 5 because we will return FALSE
+    // anyhow in such case - but may be should still give an assert for it?
+
+    // take the current month/year if none specified
+    ReplaceDefaultYearMonthWithCurrent(&year, &month);
+
+    wxDateTime dt;
+
+    // TODO this probably could be optimised somehow...
+
+    if ( n > 0 )
+    {
+        // get the first day of the month
+        dt.Set(1, month, year);
+
+        // get its wday
+        WeekDay wdayFirst = dt.GetWeekDay();
+
+        // go to the first weekday of the month
+        int diff = weekday - wdayFirst;
+        if ( diff < 0 )
+            diff += 7;
+
+        // add advance n-1 weeks more
+        diff += 7*(n - 1);
+
+        dt += wxDateSpan::Days(diff);
+    }
+    else // count from the end of the month
+    {
+        // get the last day of the month
+        dt.SetToLastMonthDay(month, year);
+
+        // get its wday
+        WeekDay wdayLast = dt.GetWeekDay();
+
+        // go to the last weekday of the month
+        int diff = wdayLast - weekday;
+        if ( diff < 0 )
+            diff += 7;
+
+        // and rewind n-1 weeks from there
+        diff += 7*(-n - 1);
+
+        dt -= wxDateSpan::Days(diff);
+    }
+
+    // check that it is still in the same month
+    if ( dt.GetMonth() == month )
+    {
+        *this = dt;
+
+        return TRUE;
+    }
+    else
+    {
+        // no such day in this month
+        return FALSE;
+    }
+}
+
+wxDateTime::wxDateTime_t wxDateTime::GetDayOfYear(const TimeZone& tz) const
+{
+    Tm tm(GetTm(tz));
+
+    return gs_cumulatedDays[IsLeapYear(tm.year)][tm.mon] + tm.mday;
+}
+
+wxDateTime::wxDateTime_t wxDateTime::GetWeekOfYear(wxDateTime::WeekFlags flags,
+                                                   const TimeZone& tz) const
+{
+    if ( flags == Default_First )
+    {
+        flags = GetCountry() == USA ? Sunday_First : Monday_First;
+    }
+
+    wxDateTime_t nDayInYear = GetDayOfYear(tz);
+    wxDateTime_t week;
+
+    WeekDay wd = GetWeekDay(tz);
+    if ( flags == Sunday_First )
+    {
+        week = (nDayInYear - wd + 7) / 7;
+    }
+    else
+    {
+        // have to shift the week days values
+        week = (nDayInYear - (wd - 1 + 7) % 7 + 7) / 7;
+    }
+
+    // FIXME some more elegant way??
+    WeekDay wdYearStart = wxDateTime(1, Jan, GetYear()).GetWeekDay();
+    if ( wdYearStart == Wed || wdYearStart == Thu )
+    {
+        week++;
+    }
+
+    return week;
+}
+
+wxDateTime::wxDateTime_t wxDateTime::GetWeekOfMonth(wxDateTime::WeekFlags flags,
+                                                    const TimeZone& tz) const
+{
+    Tm tm = GetTm(tz);
+    wxDateTime dtMonthStart = wxDateTime(1, tm.mon, tm.year);
+    int nWeek = GetWeekOfYear(flags) - dtMonthStart.GetWeekOfYear(flags) + 1;
+    if ( nWeek < 0 )
+    {
+        // this may happen for January when Jan, 1 is the last week of the
+        // previous year
+        nWeek += IsLeapYear(tm.year - 1) ? 53 : 52;
+    }
+
+    return (wxDateTime::wxDateTime_t)nWeek;
+}
+
+wxDateTime& wxDateTime::SetToYearDay(wxDateTime::wxDateTime_t yday)
+{
+    int year = GetYear();
+    wxCHECK_MSG( (0 < yday) && (yday <= GetNumberOfDays(year)),
+                 wxInvalidDateTime, _T("invalid year day") );
+
+    bool isLeap = IsLeapYear(year);
+    for ( Month mon = Jan; mon < Inv_Month; wxNextMonth(mon) )
+    {
+        // for Dec, we can't compare with gs_cumulatedDays[mon + 1], but we
+        // don't need it neither - because of the CHECK above we know that
+        // yday lies in December then
+        if ( (mon == Dec) || (yday < gs_cumulatedDays[isLeap][mon + 1]) )
+        {
+            Set(yday - gs_cumulatedDays[isLeap][mon], mon, year);
+
+            break;
+        }
+    }
+
+    return *this;
+}
+
+// ----------------------------------------------------------------------------
+// Julian day number conversion and related stuff
+// ----------------------------------------------------------------------------
+
+double wxDateTime::GetJulianDayNumber() const
+{
+    // 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;
+}
+
+double wxDateTime::GetRataDie() const
+{
+    // 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
+    {
+        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, bool noDST)
+{
+    long secDiff = GetTimeZone() + tz.GetOffset();
+
+    // we need to know whether DST is or not in effect for this date unless
+    // the test disabled by the caller
+    if ( !noDST && (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 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;
+        if ( tz.GetOffset() == -GetTimeZone() )
+        {
+            // we are working with local time
+            tm = localtime(&time);
+
+            // should never happen
+            wxCHECK_MSG( tm, wxEmptyString, _T("localtime() failed") );
+        }
+        else
+        {
+            time += (int)tz.GetOffset();
+
+#ifdef __VMS__ // time is unsigned so avoid the warning
+            int time2 = (int) time;
+            if ( time2 >= 0 )
+#else
+            if ( time >= 0 )
+#endif
+            {
+                tm = gmtime(&time);
+
+                // should never happen
+                wxCHECK_MSG( tm, wxEmptyString, _T("gmtime() failed") );
+            }
+            else
+            {
+                tm = (struct tm *)NULL;
+            }
+        }
+
+        if ( tm )
+        {
+            return CallStrftime(format, tm);
+        }
+        //else: use generic code below
+    }
+
+    // we only parse ANSI C format specifications here, no POSIX 2
+    // complications, no GNU extensions
+    Tm tm = GetTm(tz);
+
+    // used for calls to strftime() when we only deal with time
+    struct tm tmTimeOnly;
+    tmTimeOnly.tm_hour = tm.hour;
+    tmTimeOnly.tm_min = tm.min;
+    tmTimeOnly.tm_sec = tm.sec;
+    tmTimeOnly.tm_wday = 0;
+    tmTimeOnly.tm_yday = 0;
+    tmTimeOnly.tm_mday = 1;         // any date will do
+    tmTimeOnly.tm_mon = 0;
+    tmTimeOnly.tm_year = 76;
+    tmTimeOnly.tm_isdst = 0;        // no DST, we adjust for tz ourselves
+
+    wxString tmp, res, fmt;
+    for ( const wxChar *p = format; *p; p++ )
+    {
+        if ( *p != _T('%') )
+        {
+            // copy as is
+            res += *p;
+
+            continue;
+        }
+
+        // set the default format
+        switch ( *++p )
+        {
+            case _T('Y'):               // year has 4 digits
+                fmt = _T("%04d");
+                break;
+
+            case _T('j'):               // day of year has 3 digits
+                fmt = _T("%03d");
+                break;
+
+            default:
+                // it's either another valid format specifier in which case
+                // the format is "%02d" (for all the rest) or we have the
+                // field width preceding the format in which case it will
+                // override the default format anyhow
+                fmt = _T("%02d");
+        }
+
+restart:
+        // start of the format specification
+        switch ( *p )
+        {
+            case _T('a'):       // a weekday name
+            case _T('A'):
+                // second parameter should be TRUE for abbreviated names
+                res += GetWeekDayName(tm.GetWeekDay(),
+                                      *p == _T('a') ? Name_Abbr : Name_Full);
+                break;
+
+            case _T('b'):       // a month name
+            case _T('B'):
+                res += GetMonthName(tm.mon,
+                                    *p == _T('b') ? Name_Abbr : Name_Full);
+                break;
+
+            case _T('c'):       // locale default date and time  representation
+            case _T('x'):       // locale default date representation
+                //
+                // the problem: there is no way to know what do these format
+                // specifications correspond to for the current locale.
+                //
+                // the solution: 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!
+                //
+                // the bugs: we assume that neither of %c nor %x contains any
+                // fields which may change between the YEAR and real year. For
+                // example, the week number (%U, %W) and the day number (%j)
+                // will change if one of these years is leap and the other one
+                // is not!
+                {
+                    // 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.
+
+                    int yearReal = GetYear(tz);
+                    int mod28 = yearReal % 28;
+
+                    // be careful to not go too far - we risk to leave the
+                    // supported range
+                    int year;
+                    if ( mod28 < 10 )
+                    {
+                        year = 1988 + mod28;      // 1988 == 0 (mod 28)
+                    }
+                    else
+                    {
+                        year = 1970 + mod28 - 10; // 1970 == 10 (mod 28)
+                    }
+
+                    int nCentury = year / 100,
+                        nCenturyReal = yearReal / 100;
+
+                    // need to adjust for the years divisble by 400 which are
+                    // not leap but are counted like leap ones if we just take
+                    // the number of centuries in between for nLostWeekDays
+                    int nLostWeekDays = (nCentury - nCenturyReal) -
+                                        (nCentury / 4 - nCenturyReal / 4);
+
+                    // we have to gain back the "lost" weekdays: note that the
+                    // effect of this loop is to not do anything to
+                    // nLostWeekDays (which we won't use any more), but to
+                    // (indirectly) set the year correctly
+                    while ( (nLostWeekDays % 7) != 0 )
+                    {
+                        nLostWeekDays += year++ % 4 ? 1 : 2;
+                    }
+
+                    // at any rate, we couldn't go further than 1988 + 9 + 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
+                    //
+                    // NB: we assume that strftime() doesn't check for the
+                    //     date validity and will happily format the date
+                    //     corresponding to Feb 29 of a non leap year (which
+                    //     may happen if yearReal was leap and year is not)
+                    struct tm tmAdjusted;
+                    InitTm(tmAdjusted);
+                    tmAdjusted.tm_hour = tm.hour;
+                    tmAdjusted.tm_min = tm.min;
+                    tmAdjusted.tm_sec = tm.sec;
+                    tmAdjusted.tm_wday = tm.GetWeekDay();
+                    tmAdjusted.tm_yday = GetDayOfYear();
+                    tmAdjusted.tm_mday = tm.mday;
+                    tmAdjusted.tm_mon = tm.mon;
+                    tmAdjusted.tm_year = year - 1900;
+                    tmAdjusted.tm_isdst = 0; // no DST, already adjusted
+                    wxString str = CallStrftime(*p == _T('c') ? _T("%c")
+                                                              : _T("%x"),
+                                                &tmAdjusted);
+
+                    // 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);
+                    }
+
+                    res += str;
+                }
+                break;
+
+            case _T('d'):       // day of a month (01-31)
+                res += wxString::Format(fmt, tm.mday);
+                break;
+
+            case _T('H'):       // hour in 24h format (00-23)
+                res += wxString::Format(fmt, tm.hour);
+                break;
+
+            case _T('I'):       // hour in 12h format (01-12)
+                {
+                    // 24h -> 12h, 0h -> 12h too
+                    int hour12 = tm.hour > 12 ? tm.hour - 12
+                                              : tm.hour ? tm.hour : 12;
+                    res += wxString::Format(fmt, hour12);
+                }
+                break;
+
+            case _T('j'):       // day of the year
+                res += wxString::Format(fmt, GetDayOfYear(tz));
+                break;
+
+            case _T('m'):       // month as a number (01-12)
+                res += wxString::Format(fmt, tm.mon + 1);
+                break;
+
+            case _T('M'):       // minute as a decimal number (00-59)
+                res += wxString::Format(fmt, tm.min);
+                break;
+
+            case _T('p'):       // AM or PM string
+                res += CallStrftime(_T("%p"), &tmTimeOnly);
+                break;
+
+            case _T('S'):       // second as a decimal number (00-61)
+                res += wxString::Format(fmt, tm.sec);
+                break;
+
+            case _T('U'):       // week number in the year (Sunday 1st week day)
+                res += wxString::Format(fmt, GetWeekOfYear(Sunday_First, tz));
+                break;
+
+            case _T('W'):       // week number in the year (Monday 1st week day)
+                res += wxString::Format(fmt, GetWeekOfYear(Monday_First, tz));
+                break;
+
+            case _T('w'):       // weekday as a number (0-6), Sunday = 0
+                res += wxString::Format(fmt, tm.GetWeekDay());
+                break;
+
+            // case _T('x'): -- handled with "%c"
+
+            case _T('X'):       // locale default time representation
+                // just use strftime() to format the time for us
+                res += CallStrftime(_T("%X"), &tmTimeOnly);
+                break;
+
+            case _T('y'):       // year without century (00-99)
+                res += wxString::Format(fmt, tm.year % 100);
+                break;
+
+            case _T('Y'):       // year with century
+                res += wxString::Format(fmt, tm.year);
+                break;
+
+            case _T('Z'):       // timezone name
+                res += CallStrftime(_T("%Z"), &tmTimeOnly);
+                break;
+
+            default:
+                // is it the format width?
+                fmt.Empty();
+                while ( *p == _T('-') || *p == _T('+') ||
+                        *p == _T(' ') || wxIsdigit(*p) )
+                {
+                    fmt += *p;
+                }
+
+                if ( !fmt.IsEmpty() )
+                {
+                    // we've only got the flags and width so far in fmt
+                    fmt.Prepend(_T('%'));
+                    fmt.Append(_T('d'));
+
+                    goto restart;
+                }
+
+                // no, it wasn't the width
+                wxFAIL_MSG(_T("unknown format specificator"));
+
+                // fall through and just copy it nevertheless
+
+            case _T('%'):       // a percent sign
+                res += *p;
+                break;
+
+            case 0:             // the end of string
+                wxFAIL_MSG(_T("missing format at the end of string"));
+
+                // just put the '%' which was the last char in format
+                res += _T('%');
+                break;
+        }
+    }
+
+    return res;
+}
+
+// this function parses a string in (strict) RFC 822 format: see the section 5
+// of the RFC for the detailed description, but briefly it's something of the
+// form "Sat, 18 Dec 1999 00:48:30 +0100"
+//
+// this function is "strict" by design - it must reject anything except true
+// RFC822 time specs.
+//
+// TODO a great candidate for using reg exps
+const wxChar *wxDateTime::ParseRfc822Date(const wxChar* date)
+{
+    wxCHECK_MSG( date, (wxChar *)NULL, _T("NULL pointer in wxDateTime::Parse") );
+
+    const wxChar *p = date;
+    const wxChar *comma = wxStrchr(p, _T(','));
+    if ( comma )
+    {
+        // the part before comma is the weekday
+
+        // skip it for now - we don't use but might check that it really
+        // corresponds to the specfied date
+        p = comma + 1;
+
+        if ( *p != _T(' ') )
+        {
+            wxLogDebug(_T("no space after weekday in RFC822 time spec"));
+
+            return (wxChar *)NULL;
+        }
+
+        p++; // skip space
+    }
+
+    // the following 1 or 2 digits are the day number
+    if ( !wxIsdigit(*p) )
+    {
+        wxLogDebug(_T("day number expected in RFC822 time spec, none found"));
+
+        return (wxChar *)NULL;
+    }
+
+    wxDateTime_t day = *p++ - _T('0');
+    if ( wxIsdigit(*p) )
+    {
+        day *= 10;
+        day += *p++ - _T('0');
+    }
+
+    if ( *p++ != _T(' ') )
+    {
+        return (wxChar *)NULL;
+    }
+
+    // the following 3 letters specify the month
+    wxString monName(p, 3);
+    Month mon;
+    if ( monName == _T("Jan") )
+        mon = Jan;
+    else if ( monName == _T("Feb") )
+        mon = Feb;
+    else if ( monName == _T("Mar") )
+        mon = Mar;
+    else if ( monName == _T("Apr") )
+        mon = Apr;
+    else if ( monName == _T("May") )
+        mon = May;
+    else if ( monName == _T("Jun") )
+        mon = Jun;
+    else if ( monName == _T("Jul") )
+        mon = Jul;
+    else if ( monName == _T("Aug") )
+        mon = Aug;
+    else if ( monName == _T("Sep") )
+        mon = Sep;
+    else if ( monName == _T("Oct") )
+        mon = Oct;
+    else if ( monName == _T("Nov") )
+        mon = Nov;
+    else if ( monName == _T("Dec") )
+        mon = Dec;
+    else
+    {
+        wxLogDebug(_T("Invalid RFC 822 month name '%s'"), monName.c_str());
+
+        return (wxChar *)NULL;
+    }
+
+    p += 3;
+
+    if ( *p++ != _T(' ') )
+    {
+        return (wxChar *)NULL;
+    }
+
+    // next is the year
+    if ( !wxIsdigit(*p) )
+    {
+        // no year?
+        return (wxChar *)NULL;
+    }
+
+    int year = *p++ - _T('0');
+
+    if ( !wxIsdigit(*p) )
+    {
+        // should have at least 2 digits in the year
+        return (wxChar *)NULL;
+    }
+
+    year *= 10;
+    year += *p++ - _T('0');
+
+    // is it a 2 digit year (as per original RFC 822) or a 4 digit one?
+    if ( wxIsdigit(*p) )
+    {
+        year *= 10;
+        year += *p++ - _T('0');
+
+        if ( !wxIsdigit(*p) )
+        {
+            // no 3 digit years please
+            return (wxChar *)NULL;
+        }
+
+        year *= 10;
+        year += *p++ - _T('0');
+    }
+
+    if ( *p++ != _T(' ') )
+    {
+        return (wxChar *)NULL;
+    }
+
+    // time is in the format hh:mm:ss and seconds are optional
+    if ( !wxIsdigit(*p) )
+    {
+        return (wxChar *)NULL;
+    }
+
+    wxDateTime_t hour = *p++ - _T('0');
+
+    if ( !wxIsdigit(*p) )
+    {
+        return (wxChar *)NULL;
+    }
+
+    hour *= 10;
+    hour += *p++ - _T('0');
+
+    if ( *p++ != _T(':') )
+    {
+        return (wxChar *)NULL;
+    }
+
+    if ( !wxIsdigit(*p) )
+    {
+        return (wxChar *)NULL;
+    }
+
+    wxDateTime_t min = *p++ - _T('0');
+
+    if ( !wxIsdigit(*p) )
+    {
+        return (wxChar *)NULL;
+    }
+
+    min *= 10;
+    min += *p++ - _T('0');
+
+    wxDateTime_t sec = 0;
+    if ( *p++ == _T(':') )
+    {
+        if ( !wxIsdigit(*p) )
+        {
+            return (wxChar *)NULL;
+        }
+
+        sec = *p++ - _T('0');
+
+        if ( !wxIsdigit(*p) )
+        {
+            return (wxChar *)NULL;
+        }
+
+        sec *= 10;
+        sec += *p++ - _T('0');
+    }
+
+    if ( *p++ != _T(' ') )
+    {
+        return (wxChar *)NULL;
+    }
+
+    // and now the interesting part: the timezone
+    int offset;
+    if ( *p == _T('-') || *p == _T('+') )
+    {
+        // the explicit offset given: it has the form of hhmm
+        bool plus = *p++ == _T('+');
+
+        if ( !wxIsdigit(*p) || !wxIsdigit(*(p + 1)) )
+        {
+            return (wxChar *)NULL;
+        }
+
+        // hours
+        offset = 60*(10*(*p - _T('0')) + (*(p + 1) - _T('0')));
+
+        p += 2;
+
+        if ( !wxIsdigit(*p) || !wxIsdigit(*(p + 1)) )
+        {
+            return (wxChar *)NULL;
+        }
+
+        // minutes
+        offset += 10*(*p - _T('0')) + (*(p + 1) - _T('0'));
+
+        if ( !plus )
+        {
+            offset = -offset;
+        }
+
+        p += 2;
+    }
+    else
+    {
+        // the symbolic timezone given: may be either military timezone or one
+        // of standard abbreviations
+        if ( !*(p + 1) )
+        {
+            // military: Z = UTC, J unused, A = -1, ..., Y = +12
+            static const int offsets[26] =
+            {
+                //A  B   C   D   E   F   G   H   I    J    K    L    M
+                -1, -2, -3, -4, -5, -6, -7, -8, -9,   0, -10, -11, -12,
+                //N  O   P   R   Q   S   T   U   V    W    Z    Y    Z
+                +1, +2, +3, +4, +5, +6, +7, +8, +9, +10, +11, +12, 0
+            };
+
+            if ( *p < _T('A') || *p > _T('Z') || *p == _T('J') )
+            {
+                wxLogDebug(_T("Invalid militaty timezone '%c'"), *p);
+
+                return (wxChar *)NULL;
+            }
+
+            offset = offsets[*p++ - _T('A')];
+        }
+        else
+        {
+            // abbreviation
+            wxString tz = p;
+            if ( tz == _T("UT") || tz == _T("UTC") || tz == _T("GMT") )
+                offset = 0;
+            else if ( tz == _T("AST") )
+                offset = AST - GMT0;
+            else if ( tz == _T("ADT") )
+                offset = ADT - GMT0;
+            else if ( tz == _T("EST") )
+                offset = EST - GMT0;
+            else if ( tz == _T("EDT") )
+                offset = EDT - GMT0;
+            else if ( tz == _T("CST") )
+                offset = CST - GMT0;
+            else if ( tz == _T("CDT") )
+                offset = CDT - GMT0;
+            else if ( tz == _T("MST") )
+                offset = MST - GMT0;
+            else if ( tz == _T("MDT") )
+                offset = MDT - GMT0;
+            else if ( tz == _T("PST") )
+                offset = PST - GMT0;
+            else if ( tz == _T("PDT") )
+                offset = PDT - GMT0;
+            else
+            {
+                wxLogDebug(_T("Unknown RFC 822 timezone '%s'"), p);
+
+                return (wxChar *)NULL;
+            }
+
+            p += tz.length();
+        }
+
+        // make it minutes
+        offset *= 60;
+    }
+
+    // the spec was correct
+    Set(day, mon, year, hour, min, sec);
+    MakeTimezone((wxDateTime_t)(60*offset));
+
+    return p;
+}
+
+const wxChar *wxDateTime::ParseFormat(const wxChar *date,
+                                      const wxChar *format,
+                                      const wxDateTime& dateDef)
+{
+    wxCHECK_MSG( date && format, (wxChar *)NULL,
+                 _T("NULL pointer in wxDateTime::ParseFormat()") );
+
+    wxString str;
+    unsigned long num;
+
+    // what fields have we found?
+    bool haveWDay = FALSE,
+         haveYDay = FALSE,
+         haveDay = FALSE,
+         haveMon = FALSE,
+         haveYear = FALSE,
+         haveHour = FALSE,
+         haveMin = FALSE,
+         haveSec = FALSE;
+
+    bool hourIsIn12hFormat = FALSE, // or in 24h one?
+         isPM = FALSE;              // AM by default
+
+    // and the value of the items we have (init them to get rid of warnings)
+    wxDateTime_t sec = 0,
+                 min = 0,
+                 hour = 0;
+    WeekDay wday = Inv_WeekDay;
+    wxDateTime_t yday = 0,
+                 mday = 0;
+    wxDateTime::Month mon = Inv_Month;
+    int year = 0;
+
+    const wxChar *input = date;
+    for ( const wxChar *fmt = format; *fmt; fmt++ )
+    {
+        if ( *fmt != _T('%') )
+        {
+            if ( wxIsspace(*fmt) )
+            {
+                // a white space in the format string matches 0 or more white
+                // spaces in the input
+                while ( wxIsspace(*input) )
+                {
+                    input++;
+                }
+            }
+            else // !space
+            {
+                // any other character (not whitespace, not '%') must be
+                // matched by itself in the input
+                if ( *input++ != *fmt )
+                {
+                    // no match
+                    return (wxChar *)NULL;
+                }
+            }
+
+            // done with this format char
+            continue;
+        }
+
+        // start of a format specification
+        switch ( *++fmt )
+        {
+            case _T('a'):       // a weekday name
+            case _T('A'):
+                {
+                    int flag = *fmt == _T('a') ? Name_Abbr : Name_Full;
+                    wday = GetWeekDayFromName(GetAlphaToken(input), flag);
+                    if ( wday == Inv_WeekDay )
+                    {
+                        // no match
+                        return (wxChar *)NULL;
+                    }
+                }
+                haveWDay = TRUE;
+                break;
+
+            case _T('b'):       // a month name
+            case _T('B'):
+                {
+                    int flag = *fmt == _T('b') ? Name_Abbr : Name_Full;
+                    mon = GetMonthFromName(GetAlphaToken(input), flag);
+                    if ( mon == Inv_Month )
+                    {
+                        // no match
+                        return (wxChar *)NULL;
+                    }
+                }
+                haveMon = TRUE;
+                break;
+
+            case _T('c'):       // locale default date and time  representation
+                {
+                    wxDateTime dt;
+
+                    // this is the format which corresponds to ctime() output
+                    // and strptime("%c") should parse it, so try it first
+                    static const wxChar *fmtCtime = _T("%a %b %d %H:%M:%S %Y");
+
+                    const wxChar *result = dt.ParseFormat(input, fmtCtime);
+                    if ( !result )
+                    {
+                        result = dt.ParseFormat(input, _T("%x %X"));
+                    }
+
+                    if ( !result )
+                    {
+                        result = dt.ParseFormat(input, _T("%X %x"));
+                    }
+
+                    if ( !result )
+                    {
+                        // we've tried everything and still no match
+                        return (wxChar *)NULL;
+                    }
+
+                    Tm tm = dt.GetTm();
+
+                    haveDay = haveMon = haveYear =
+                    haveHour = haveMin = haveSec = TRUE;
+
+                    hour = tm.hour;
+                    min = tm.min;
+                    sec = tm.sec;
+
+                    year = tm.year;
+                    mon = tm.mon;
+                    mday = tm.mday;
+
+                    input = result;
+                }
+                break;
+
+            case _T('d'):       // day of a month (01-31)
+                if ( !GetNumericToken(input, &num) || (num > 31) )
+                {
+                    // no match
+                    return (wxChar *)NULL;
+                }
+
+                // we can't check whether the day range is correct yet, will
+                // do it later - assume ok for now
+                haveDay = TRUE;
+                mday = (wxDateTime_t)num;
+                break;
+
+            case _T('H'):       // hour in 24h format (00-23)
+                if ( !GetNumericToken(input, &num) || (num > 23) )
+                {
+                    // no match
+                    return (wxChar *)NULL;
+                }
+
+                haveHour = TRUE;
+                hour = (wxDateTime_t)num;
+                break;
+
+            case _T('I'):       // hour in 12h format (01-12)
+                if ( !GetNumericToken(input, &num) || !num || (num > 12) )
+                {
+                    // no match
+                    return (wxChar *)NULL;
+                }
+
+                haveHour = TRUE;
+                hourIsIn12hFormat = TRUE;
+                hour = (wxDateTime_t)(num % 12);        // 12 should be 0
+                break;
+
+            case _T('j'):       // day of the year
+                if ( !GetNumericToken(input, &num) || !num || (num > 366) )
+                {
+                    // no match
+                    return (wxChar *)NULL;
+                }
+
+                haveYDay = TRUE;
+                yday = (wxDateTime_t)num;
+                break;
+
+            case _T('m'):       // month as a number (01-12)
+                if ( !GetNumericToken(input, &num) || !num || (num > 12) )
+                {
+                    // no match
+                    return (wxChar *)NULL;
+                }
+
+                haveMon = TRUE;
+                mon = (Month)(num - 1);
+                break;
+
+            case _T('M'):       // minute as a decimal number (00-59)
+                if ( !GetNumericToken(input, &num) || (num > 59) )
+                {
+                    // no match
+                    return (wxChar *)NULL;
+                }
+
+                haveMin = TRUE;
+                min = (wxDateTime_t)num;
+                break;
+
+            case _T('p'):       // AM or PM string
+                {
+                    wxString am, pm, token = GetAlphaToken(input);
+
+                    GetAmPmStrings(&am, &pm);
+                    if ( token.CmpNoCase(pm) == 0 )
+                    {
+                        isPM = TRUE;
+                    }
+                    else if ( token.CmpNoCase(am) != 0 )
+                    {
+                        // no match
+                        return (wxChar *)NULL;
+                    }
+                }
+                break;
+
+            case _T('r'):       // time as %I:%M:%S %p
+                {
+                    wxDateTime dt;
+                    input = dt.ParseFormat(input, _T("%I:%M:%S %p"));
+                    if ( !input )
+                    {
+                        // no match
+                        return (wxChar *)NULL;
+                    }
+
+                    haveHour = haveMin = haveSec = TRUE;
+
+                    Tm tm = dt.GetTm();
+                    hour = tm.hour;
+                    min = tm.min;
+                    sec = tm.sec;
+                }
+                break;
+
+            case _T('R'):       // time as %H:%M
+                {
+                    wxDateTime dt;
+                    input = dt.ParseFormat(input, _T("%H:%M"));
+                    if ( !input )
+                    {
+                        // no match
+                        return (wxChar *)NULL;
+                    }
+
+                    haveHour = haveMin = TRUE;
+
+                    Tm tm = dt.GetTm();
+                    hour = tm.hour;
+                    min = tm.min;
+                }
+
+            case _T('S'):       // second as a decimal number (00-61)
+                if ( !GetNumericToken(input, &num) || (num > 61) )
+                {
+                    // no match
+                    return (wxChar *)NULL;
+                }
+
+                haveSec = TRUE;
+                sec = (wxDateTime_t)num;
+                break;
+
+            case _T('T'):       // time as %H:%M:%S
+                {
+                    wxDateTime dt;
+                    input = dt.ParseFormat(input, _T("%H:%M:%S"));
+                    if ( !input )
+                    {
+                        // no match
+                        return (wxChar *)NULL;
+                    }
+
+                    haveHour = haveMin = haveSec = TRUE;
+
+                    Tm tm = dt.GetTm();
+                    hour = tm.hour;
+                    min = tm.min;
+                    sec = tm.sec;
+                }
+                break;
+
+            case _T('w'):       // weekday as a number (0-6), Sunday = 0
+                if ( !GetNumericToken(input, &num) || (wday > 6) )
+                {
+                    // no match
+                    return (wxChar *)NULL;
+                }
+
+                haveWDay = TRUE;
+                wday = (WeekDay)num;
+                break;
+
+            case _T('x'):       // locale default date representation
+#ifdef HAVE_STRPTIME
+                // try using strptime() - it may fail even if the input is
+                // correct but the date is out of range, so we will fall back
+                // to our generic code anyhow (FIXME !Unicode friendly)
+                {
+                    struct tm tm;
+                    const wxChar *result = strptime(input, "%x", &tm);
+                    if ( result )
+                    {
+                        input = result;
+
+                        haveDay = haveMon = haveYear = TRUE;
+
+                        year = 1900 + tm.tm_year;
+                        mon = (Month)tm.tm_mon;
+                        mday = tm.tm_mday;
+
+                        break;
+                    }
+                }
+#endif // HAVE_STRPTIME
+
+                // TODO query the LOCALE_IDATE setting under Win32
+                {
+                    wxDateTime dt;
+
+                    wxString fmtDate, fmtDateAlt;
+                    if ( IsWestEuropeanCountry(GetCountry()) ||
+                         GetCountry() == Russia )
+                    {
+                        fmtDate = _T("%d/%m/%y");
+                        fmtDateAlt = _T("%m/%d/%y");
+                    }
+                    else // assume USA
+                    {
+                        fmtDate = _T("%m/%d/%y");
+                        fmtDateAlt = _T("%d/%m/%y");
+                    }
+
+                    const wxChar *result = dt.ParseFormat(input, fmtDate);
+
+                    if ( !result )
+                    {
+                        // ok, be nice and try another one
+                        result = dt.ParseFormat(input, fmtDateAlt);
+                    }
+
+                    if ( !result )
+                    {
+                        // bad luck
+                        return (wxChar *)NULL;
+                    }
+
+                    Tm tm = dt.GetTm();
+
+                    haveDay = haveMon = haveYear = TRUE;
+
+                    year = tm.year;
+                    mon = tm.mon;
+                    mday = tm.mday;
+
+                    input = result;
+                }
+
+                break;
+
+            case _T('X'):       // locale default time representation
+#ifdef HAVE_STRPTIME
+                {
+                    // use strptime() to do it for us (FIXME !Unicode friendly)
+                    struct tm tm;
+                    input = strptime(input, "%X", &tm);
+                    if ( !input )
+                    {
+                        return (wxChar *)NULL;
+                    }
+
+                    haveHour = haveMin = haveSec = TRUE;
+
+                    hour = tm.tm_hour;
+                    min = tm.tm_min;
+                    sec = tm.tm_sec;
+                }
+#else // !HAVE_STRPTIME
+                // TODO under Win32 we can query the LOCALE_ITIME system
+                //      setting which says whether the default time format is
+                //      24 or 12 hour
+                {
+                    // try to parse what follows as "%H:%M:%S" and, if this
+                    // fails, as "%I:%M:%S %p" - this should catch the most
+                    // common cases
+                    wxDateTime dt;
+
+                    const wxChar *result = dt.ParseFormat(input, _T("%T"));
+                    if ( !result )
+                    {
+                        result = dt.ParseFormat(input, _T("%r"));
+                    }
+
+                    if ( !result )
+                    {
+                        // no match
+                        return (wxChar *)NULL;
+                    }
+
+                    haveHour = haveMin = haveSec = TRUE;
+
+                    Tm tm = dt.GetTm();
+                    hour = tm.hour;
+                    min = tm.min;
+                    sec = tm.sec;
+
+                    input = result;
+                }
+#endif // HAVE_STRPTIME/!HAVE_STRPTIME
+                break;
+
+            case _T('y'):       // year without century (00-99)
+                if ( !GetNumericToken(input, &num) || (num > 99) )
+                {
+                    // no match
+                    return (wxChar *)NULL;
+                }
+
+                haveYear = TRUE;
+                year = 1900 + (wxDateTime_t)num;
+                break;
+
+            case _T('Y'):       // year with century
+                if ( !GetNumericToken(input, &num) )
+                {
+                    // no match
+                    return (wxChar *)NULL;
+                }
+
+                haveYear = TRUE;
+                year = (wxDateTime_t)num;
+                break;
+
+            case _T('Z'):       // timezone name
+                wxFAIL_MSG(_T("TODO"));
+                break;
+
+            case _T('%'):       // a percent sign
+                if ( *input++ != _T('%') )
+                {
+                    // no match
+                    return (wxChar *)NULL;
+                }
+                break;
+
+            case 0:             // the end of string
+                wxFAIL_MSG(_T("unexpected format end"));
+
+                // fall through
+
+            default:            // not a known format spec
+                return (wxChar *)NULL;
+        }
+    }
+
+    // format matched, try to construct a date from what we have now
+    Tm tmDef;
+    if ( dateDef.IsValid() )
+    {
+        // take this date as default
+        tmDef = dateDef.GetTm();
+    }
+    else if ( m_time != 0 )
+    {
+        // if this date is valid, don't change it
+        tmDef = GetTm();
+    }
+    else
+    {
+        // no default and this date is invalid - fall back to Today()
+        tmDef = Today().GetTm();
+    }
+
+    Tm tm = tmDef;
+
+    // set the date
+    if ( haveYear )
+    {
+        tm.year = year;
+    }
+
+    // TODO we don't check here that the values are consistent, if both year
+    //      day and month/day were found, we just ignore the year day and we
+    //      also always ignore the week day
+    if ( haveMon && haveDay )
+    {
+        if ( mday > GetNumOfDaysInMonth(tm.year, mon) )
+        {
+            wxLogDebug(_T("bad month day in wxDateTime::ParseFormat"));
+
+            return (wxChar *)NULL;
+        }
+
+        tm.mon = mon;
+        tm.mday = mday;
+    }
+    else if ( haveYDay )
+    {
+        if ( yday > GetNumberOfDays(tm.year) )
+        {
+            wxLogDebug(_T("bad year day in wxDateTime::ParseFormat"));
+
+            return (wxChar *)NULL;
+        }
+
+        Tm tm2 = wxDateTime(1, Jan, tm.year).SetToYearDay(yday).GetTm();
+
+        tm.mon = tm2.mon;
+        tm.mday = tm2.mday;
+    }
+
+    // deal with AM/PM
+    if ( haveHour && hourIsIn12hFormat && isPM )
+    {
+        // translate to 24hour format
+        hour += 12;
+    }
+    //else: either already in 24h format or no translation needed
+
+    // set the time
+    if ( haveHour )
+    {
+        tm.hour = hour;
+    }
+
+    if ( haveMin )
+    {
+        tm.min = min;
+    }
+
+    if ( haveSec )
+    {
+        tm.sec = sec;
+    }
+
+    Set(tm);
+
+    return input;
+}
+
+const wxChar *wxDateTime::ParseDateTime(const wxChar *date)
+{
+    wxCHECK_MSG( date, (wxChar *)NULL, _T("NULL pointer in wxDateTime::Parse") );
+
+    // there is a public domain version of getdate.y, but it only works for
+    // English...
+    wxFAIL_MSG(_T("TODO"));
+
+    return (wxChar *)NULL;
+}
+
+const wxChar *wxDateTime::ParseDate(const wxChar *date)
+{
+    // this is a simplified version of ParseDateTime() which understands only
+    // "today" (for wxDate compatibility) and digits only otherwise (and not
+    // all esoteric constructions ParseDateTime() knows about)
+
+    wxCHECK_MSG( date, (wxChar *)NULL, _T("NULL pointer in wxDateTime::Parse") );
+
+    const wxChar *p = date;
+    while ( wxIsspace(*p) )
+        p++;
+
+    // some special cases
+    static struct
+    {
+        const wxChar *str;
+        int dayDiffFromToday;
+    } literalDates[] =
+    {
+        { wxTRANSLATE("today"),             0 },
+        { wxTRANSLATE("yesterday"),        -1 },
+        { wxTRANSLATE("tomorrow"),          1 },
+    };
+
+    for ( size_t n = 0; n < WXSIZEOF(literalDates); n++ )
+    {
+        wxString date = wxGetTranslation(literalDates[n].str);
+        size_t len = date.length();
+        if ( wxString(p, len).CmpNoCase(date) == 0 )
+        {
+            // nothing can follow this, so stop here
+            p += len;
+
+            int dayDiffFromToday = literalDates[n].dayDiffFromToday;
+            *this = Today();
+            if ( dayDiffFromToday )
+            {
+                *this += wxDateSpan::Days(dayDiffFromToday);
+            }
+
+            return p;
+        }
+    }
+
+    // what do we have?
+    bool haveDay = FALSE,       // the months day?
+         haveWDay = FALSE,      // the day of week?
+         haveMon = FALSE,       // the month?
+         haveYear = FALSE;      // the year?
+
+    // and the value of the items we have (init them to get rid of warnings)
+    WeekDay wday = Inv_WeekDay;
+    wxDateTime_t day = 0;
+    wxDateTime::Month mon = Inv_Month;
+    int year = 0;
+
+    // tokenize the string
+    wxStringTokenizer tok(p, _T(",/-\t\n "));
+    while ( tok.HasMoreTokens() )
+    {
+        wxString token = tok.GetNextToken();
+
+        // is it a number?
+        unsigned long val;
+        if ( token.ToULong(&val) )
+        {
+            // guess what this number is
+
+            bool isDay = FALSE,
+                 isMonth = FALSE,
+                 // only years are counted from 0
+                 isYear = (val == 0) || (val > 31);
+            if ( !isYear )
+            {
+                // may be the month or month day or the year, assume the
+                // month day by default and fallback to month if the range
+                // allow it or to the year if our assumption doesn't work
+                if ( haveDay )
+                {
+                    // we already have the day, so may only be a month or year
+                    if ( val > 12 )
+                    {
+                        isYear = TRUE;
+                    }
+                    else
+                    {
+                        isMonth = TRUE;
+                    }
+                }
+                else // it may be day
+                {
+                    isDay = TRUE;
+
+                    // check the range
+                    if ( haveMon )
+                    {
+                        if ( val > GetNumOfDaysInMonth(haveYear ? year
+                                                                : Inv_Year,
+                                                       mon) )
+                        {
+                            // oops, it can't be a day finally
+                            isDay = FALSE;
+
+                            if ( val > 12 )
+                            {
+                                isYear = TRUE;
+                            }
+                            else
+                            {
+                                isMonth = TRUE;
+                            }
+                        }
+                    }
+                }
+            }
+
+            // remember that we have this and stop the scan if it's the second
+            // time we find this, except for the day logic (see there)
+            if ( isYear )
+            {
+                if ( haveYear )
+                {
+                    break;
+                }
+
+                haveYear = TRUE;
+
+                // no roll over - 99 means 99, not 1999 for us
+                year = (wxDateTime_t)val;
+            }
+            else if ( isMonth )
+            {
+                if ( haveMon )
+                {
+                    break;
+                }
+
+                haveMon = TRUE;
+
+                mon = (wxDateTime::Month)val;
+            }
+            else
+            {
+                wxASSERT_MSG( isDay, _T("logic error") );
+
+                if ( haveDay )
+                {
+                    // may be were mistaken when we found it for the first
+                    // time? may be it was a month or year instead?
+                    //
+                    // this ability to "backtrack" allows us to correctly parse
+                    // both things like 01/13 and 13/01 - but, of course, we
+                    // still can't resolve the ambiguity in 01/02 (it will be
+                    // Feb 1 for us, not Jan 2 as americans might expect!)
+                    if ( (day <= 12) && !haveMon )
+                    {
+                        // exchange day and month
+                        mon = (wxDateTime::Month)day;
+
+                        haveMon = TRUE;
+                    }
+                    else if ( !haveYear )
+                    {
+                        // exchange day and year
+                        year = day;
+
+                        haveYear = TRUE;
+                    }
+                }
+
+                haveDay = TRUE;
+
+                day = (wxDateTime_t)val;
+            }
+        }
+        else // not a number
+        {
+            mon = GetMonthFromName(token, Name_Full | Name_Abbr);
+            if ( mon != Inv_Month )
+            {
+                // it's a month
+                if ( haveMon )
+                {
+                    break;
+                }
+
+                haveMon = TRUE;
+            }
+            else
+            {
+                wday = GetWeekDayFromName(token, Name_Full | Name_Abbr);
+                if ( wday != Inv_WeekDay )
+                {
+                    // a week day
+                    if ( haveWDay )
+                    {
+                        break;
+                    }
+
+                    haveWDay = TRUE;
+                }
+                else
+                {
+                    // try the ordinals
+                    static const wxChar *ordinals[] =
+                    {
+                        wxTRANSLATE("first"),
+                        wxTRANSLATE("second"),
+                        wxTRANSLATE("third"),
+                        wxTRANSLATE("fourth"),
+                        wxTRANSLATE("fifth"),
+                        wxTRANSLATE("sixth"),
+                        wxTRANSLATE("seventh"),
+                        wxTRANSLATE("eighth"),
+                        wxTRANSLATE("ninth"),
+                        wxTRANSLATE("tenth"),
+                        wxTRANSLATE("eleventh"),
+                        wxTRANSLATE("twelfth"),
+                        wxTRANSLATE("thirteenth"),
+                        wxTRANSLATE("fourteenth"),
+                        wxTRANSLATE("fifteenth"),
+                        wxTRANSLATE("sixteenth"),
+                        wxTRANSLATE("seventeenth"),
+                        wxTRANSLATE("eighteenth"),
+                        wxTRANSLATE("nineteenth"),
+                        wxTRANSLATE("twentieth"),
+                        // that's enough - otherwise we'd have problems with
+                        // composite (or not) ordinals otherwise
+                    };
+
+                    size_t n;
+                    for ( n = 0; n < WXSIZEOF(ordinals); n++ )
+                    {
+                        if ( token.CmpNoCase(ordinals[n]) == 0 )
+                        {
+                            break;
+                        }
+                    }
+
+                    if ( n == WXSIZEOF(ordinals) )
+                    {
+                        // stop here - something unknown
+                        break;
+                    }
+
+                    // it's a day
+                    if ( haveDay )
+                    {
+                        // don't try anything here (as in case of numeric day
+                        // above) - the symbolic day spec should always
+                        // precede the month/year
+                        break;
+                    }
+
+                    haveDay = TRUE;
+
+                    day = n + 1;
+                }
+            }
+        }
+    }
+
+    // either no more tokens or the scan was stopped by something we couldn't
+    // parse - in any case, see if we can construct a date from what we have
+    if ( !haveDay && !haveWDay )
+    {
+        wxLogDebug(_T("no day, no weekday hence no date."));
+
+        return (wxChar *)NULL;
+    }
+
+    if ( haveWDay && (haveMon || haveYear || haveDay) &&
+         !(haveMon && haveMon && haveYear) )
+    {
+        // without adjectives (which we don't support here) the week day only
+        // makes sense completely separately or with the full date
+        // specification (what would "Wed 1999" mean?)
+        return (wxChar *)NULL;
+    }
+
+    if ( !haveMon )
+    {
+        mon = GetCurrentMonth();
+    }
+
+    if ( !haveYear )
+    {
+        year = GetCurrentYear();
+    }
+
+    if ( haveDay )
+    {
+        Set(day, mon, year);
+
+        if ( haveWDay )
+        {
+            // check that it is really the same
+            if ( GetWeekDay() != wday )
+            {
+                // inconsistency detected
+                return (wxChar *)NULL;
+            }
+        }
+    }
+    else // haveWDay
+    {
+        *this = Today();
+
+        SetToWeekDayInSameWeek(wday);
+    }
+
+    // return the pointer to the next char
+    return p + wxStrlen(p) - wxStrlen(tok.GetString());
+}
+
+const wxChar *wxDateTime::ParseTime(const wxChar *time)
+{
+    wxCHECK_MSG( time, (wxChar *)NULL, _T("NULL pointer in wxDateTime::Parse") );
+
+    // first try some extra things
+    static const struct
+    {
+        const wxChar *name;
+        wxDateTime_t  hour;
+    } stdTimes[] =
+    {
+        { wxTRANSLATE("noon"),      12 },
+        { wxTRANSLATE("midnight"),  00 },
+        // anything else?
+    };
+
+    for ( size_t n = 0; n < WXSIZEOF(stdTimes); n++ )
+    {
+        wxString timeString = wxGetTranslation(stdTimes[n].name);
+        size_t len = timeString.length();
+        if ( timeString.CmpNoCase(wxString(time, len)) == 0 )
+        {
+            Set(stdTimes[n].hour, 0, 0);
+
+            return time + len;
+        }
+    }
+
+    // try all time formats we may think about starting with the standard one
+    const wxChar *result = ParseFormat(time, _T("%X"));
+    if ( !result )
+    {
+        // normally, it's the same, but why not try it?
+        result = ParseFormat(time, _T("%H:%M:%S"));
+    }
+
+    if ( !result )
+    {
+        // 12hour with AM/PM?
+        result = ParseFormat(time, _T("%I:%M:%S %p"));
+    }
+
+    if ( !result )
+    {
+        // without seconds?
+        result = ParseFormat(time, _T("%H:%M"));
+    }
+
+    if ( !result )
+    {
+        // 12hour with AM/PM but without seconds?
+        result = ParseFormat(time, _T("%I:%M %p"));
+    }
+
+    if ( !result )
+    {
+        // just the hour?
+        result = ParseFormat(time, _T("%H"));
+    }
+
+    if ( !result )
+    {
+        // just the hour and AM/PM?
+        result = ParseFormat(time, _T("%I %p"));
+    }
+
+    // TODO: parse timezones
+
+    return result;
+}
+
+// ----------------------------------------------------------------------------
+// Workdays and holidays support
+// ----------------------------------------------------------------------------
+
+bool wxDateTime::IsWorkDay(Country WXUNUSED(country)) const
+{
+    return !wxDateTimeHolidayAuthority::IsHoliday(*this);
+}
+
+// ============================================================================
+// 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
+{
+    wxCHECK_MSG( format, _T(""), _T("NULL format in wxTimeSpan::Format") );
+
+    wxString str;
+    str.Alloc(wxStrlen(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("%03ld"), GetMilliseconds().ToLong());
+                    break;
+
+                case 'M':
+                    tmp.Printf(_T("%02d"), GetMinutes());
+                    break;
+
+                case 'S':
+                    tmp.Printf(_T("%02ld"), GetSeconds().ToLong());
+                    break;
+            }
+
+            if ( !!tmp )
+            {
+                str += tmp;
+
+                // skip str += ch below
+                continue;
+            }
+        }
+
+        str += ch;
+    }
+
+    return str;
+}
+
+// ============================================================================
+// wxDateTimeHolidayAuthority and related classes
+// ============================================================================
+
+#include "wx/arrimpl.cpp"
+
+WX_DEFINE_OBJARRAY(wxDateTimeArray)
+
+static int wxCMPFUNC_CONV
+wxDateTimeCompareFunc(wxDateTime **first, wxDateTime **second)
+{
+    wxDateTime dt1 = **first,
+               dt2 = **second;
+
+    return dt1 == dt2 ? 0 : dt1 < dt2 ? -1 : +1;
+}
+
+// ----------------------------------------------------------------------------
+// wxDateTimeHolidayAuthority
+// ----------------------------------------------------------------------------
+
+wxHolidayAuthoritiesArray wxDateTimeHolidayAuthority::ms_authorities;
+
+/* static */
+bool wxDateTimeHolidayAuthority::IsHoliday(const wxDateTime& dt)
+{
+    size_t count = ms_authorities.GetCount();
+    for ( size_t n = 0; n < count; n++ )
+    {
+        if ( ms_authorities[n]->DoIsHoliday(dt) )
+        {
+            return TRUE;
+        }
+    }
+
+    return FALSE;
+}
+
+/* static */
+size_t
+wxDateTimeHolidayAuthority::GetHolidaysInRange(const wxDateTime& dtStart,
+                                               const wxDateTime& dtEnd,
+                                               wxDateTimeArray& holidays)
+{
+    wxDateTimeArray hol;
+
+    holidays.Empty();
+
+    size_t count = ms_authorities.GetCount();
+    for ( size_t nAuth = 0; nAuth < count; nAuth++ )
+    {
+        ms_authorities[nAuth]->DoGetHolidaysInRange(dtStart, dtEnd, hol);
+
+        WX_APPEND_ARRAY(holidays, hol);
+    }
+
+    holidays.Sort(wxDateTimeCompareFunc);
+
+    return holidays.GetCount();
+}
+
+/* static */
+void wxDateTimeHolidayAuthority::ClearAllAuthorities()
+{
+    WX_CLEAR_ARRAY(ms_authorities);
+}
+
+/* static */
+void wxDateTimeHolidayAuthority::AddAuthority(wxDateTimeHolidayAuthority *auth)
+{
+    ms_authorities.Add(auth);
+}
+
+// ----------------------------------------------------------------------------
+// wxDateTimeWorkDays
+// ----------------------------------------------------------------------------
+
+bool wxDateTimeWorkDays::DoIsHoliday(const wxDateTime& dt) const
+{
+    wxDateTime::WeekDay wd = dt.GetWeekDay();
+
+    return (wd == wxDateTime::Sun) || (wd == wxDateTime::Sat);
+}
+
+size_t wxDateTimeWorkDays::DoGetHolidaysInRange(const wxDateTime& dtStart,
+                                                const wxDateTime& dtEnd,
+                                                wxDateTimeArray& holidays) const
+{
+    if ( dtStart > dtEnd )
+    {
+        wxFAIL_MSG( _T("invalid date range in GetHolidaysInRange") );
+
+        return 0u;
+    }
+
+    holidays.Empty();
+
+    // instead of checking all days, start with the first Sat after dtStart and
+    // end with the last Sun before dtEnd
+    wxDateTime dtSatFirst = dtStart.GetNextWeekDay(wxDateTime::Sat),
+               dtSatLast = dtEnd.GetPrevWeekDay(wxDateTime::Sat),
+               dtSunFirst = dtStart.GetNextWeekDay(wxDateTime::Sun),
+               dtSunLast = dtEnd.GetPrevWeekDay(wxDateTime::Sun),
+               dt;
+
+    for ( dt = dtSatFirst; dt <= dtSatLast; dt += wxDateSpan::Week() )
+    {
+        holidays.Add(dt);
+    }
+
+    for ( dt = dtSunFirst; dt <= dtSunLast; dt += wxDateSpan::Week() )
+    {
+        holidays.Add(dt);
+    }
+
+    return holidays.GetCount();
+}
+
+