src/common/datetime.cpp

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // Name:        src/common/datetime.cpp
   3 // Purpose:     implementation of time/date related classes
   4 //              (for formatting&parsing see datetimefmt.cpp)
   5 // Author:      Vadim Zeitlin
   6 // Modified by:
   7 // Created:     11.05.99
   8 // RCS-ID:      $Id$
   9 // Copyright:   (c) 1999 Vadim Zeitlin <zeitlin@dptmaths.ens-cachan.fr>
  10 //              parts of code taken from sndcal library by Scott E. Lee:
  11 //
  12 //               Copyright 1993-1995, Scott E. Lee, all rights reserved.
  13 //               Permission granted to use, copy, modify, distribute and sell
  14 //               so long as the above copyright and this permission statement
  15 //               are retained in all copies.
  16 //
  17 // Licence:     wxWindows licence
  18 ///////////////////////////////////////////////////////////////////////////////
  19
  20 /*
  21  * Implementation notes:
  22  *
  23  * 1. the time is stored as a 64bit integer containing the signed number of
  24  *    milliseconds since Jan 1. 1970 (the Unix Epoch) - so it is always
  25  *    expressed in GMT.
  26  *
  27  * 2. the range is thus something about 580 million years, but due to current
  28  *    algorithms limitations, only dates from Nov 24, 4714BC are handled
  29  *
  30  * 3. standard ANSI C functions are used to do time calculations whenever
  31  *    possible, i.e. when the date is in the range Jan 1, 1970 to 2038
  32  *
  33  * 4. otherwise, the calculations are done by converting the date to/from JDN
  34  *    first (the range limitation mentioned above comes from here: the
  35  *    algorithm used by Scott E. Lee's code only works for positive JDNs, more
  36  *    or less)
  37  *
  38  * 5. the object constructed for the given DD-MM-YYYY HH:MM:SS corresponds to
  39  *    this moment in local time and may be converted to the object
  40  *    corresponding to the same date/time in another time zone by using
  41  *    ToTimezone()
  42  *
  43  * 6. the conversions to the current (or any other) timezone are done when the
  44  *    internal time representation is converted to the broken-down one in
  45  *    wxDateTime::Tm.
  46  */
  47
  48 // ============================================================================
  49 // declarations
  50 // ============================================================================
  51
  52 // ----------------------------------------------------------------------------
  53 // headers
  54 // ----------------------------------------------------------------------------
  55
  56 // For compilers that support precompilation, includes "wx.h".
  57 #include "wx/wxprec.h"
  58
  59 #ifdef __BORLANDC__
  60     #pragma hdrstop
  61 #endif
  62
  63 #if !defined(wxUSE_DATETIME) || wxUSE_DATETIME
  64
  65 #ifndef WX_PRECOMP
  66     #ifdef __WXMSW__
  67         #include "wx/msw/wrapwin.h"
  68     #endif
  69     #include "wx/string.h"
  70     #include "wx/log.h"
  71     #include "wx/intl.h"
  72     #include "wx/stopwatch.h"           // for wxGetLocalTimeMillis()
  73     #include "wx/module.h"
  74     #include "wx/crt.h"
  75 #endif // WX_PRECOMP
  76
  77 #include "wx/thread.h"
  78 #include "wx/tokenzr.h"
  79
  80 #include <ctype.h>
  81
  82 #ifdef __WINDOWS__
  83     #include <winnls.h>
  84     #ifndef __WXWINCE__
  85         #include <locale.h>
  86     #endif
  87 #endif
  88
  89 #include "wx/datetime.h"
  90
  91 // ----------------------------------------------------------------------------
  92 // wxXTI
  93 // ----------------------------------------------------------------------------
  94
  95 #if wxUSE_EXTENDED_RTTI
  96
  97 template<> void wxStringReadValue(const wxString &s , wxDateTime &data )
  98 {
  99     data.ParseFormat(s,"%Y-%m-%d %H:%M:%S", NULL);
 100 }
 101
 102 template<> void wxStringWriteValue(wxString &s , const wxDateTime &data )
 103 {
 104     s = data.Format("%Y-%m-%d %H:%M:%S");
 105 }
 106
 107 wxCUSTOM_TYPE_INFO(wxDateTime, wxToStringConverter<wxDateTime> , wxFromStringConverter<wxDateTime>)
 108
 109 #endif // wxUSE_EXTENDED_RTTI
 110
 111
 112 // ----------------------------------------------------------------------------
 113 // conditional compilation
 114 // ----------------------------------------------------------------------------
 115
 116 #if defined(__MWERKS__) && wxUSE_UNICODE
 117     #include <wtime.h>
 118 #endif
 119
 120 #if !defined(WX_TIMEZONE) && !defined(WX_GMTOFF_IN_TM)
 121     #if defined(__WXPALMOS__)
 122         #define WX_GMTOFF_IN_TM
 123     #elif defined(__BORLANDC__) || defined(__MINGW32__) || defined(__VISAGECPP__)
 124         #define WX_TIMEZONE _timezone
 125     #elif defined(__MWERKS__)
 126         long wxmw_timezone = 28800;
 127         #define WX_TIMEZONE wxmw_timezone
 128     #elif defined(__DJGPP__) || defined(__WINE__)
 129         #include <sys/timeb.h>
 130         #include <values.h>
 131         static long wxGetTimeZone()
 132         {
 133             static long timezone = MAXLONG; // invalid timezone
 134             if (timezone == MAXLONG)
 135             {
 136                 struct timeb tb;
 137                 ftime(&tb);
 138                 timezone = tb.timezone;
 139             }
 140             return timezone;
 141         }
 142         #define WX_TIMEZONE wxGetTimeZone()
 143     #elif defined(__DARWIN__)
 144         #define WX_GMTOFF_IN_TM
 145     #elif defined(__WXWINCE__) && defined(__VISUALC8__)
 146         // _timezone is not present in dynamic run-time library
 147         #if 0
 148         // Solution (1): use the function equivalent of _timezone
 149         static long wxGetTimeZone()
 150         {
 151             static long s_Timezone = MAXLONG; // invalid timezone
 152             if (s_Timezone == MAXLONG)
 153             {
 154                 int t;
 155                 _get_timezone(& t);
 156                 s_Timezone = (long) t;
 157             }
 158             return s_Timezone;
 159         }
 160         #define WX_TIMEZONE wxGetTimeZone()
 161         #elif 1
 162         // Solution (2): using GetTimeZoneInformation
 163         static long wxGetTimeZone()
 164         {
 165             static long timezone = MAXLONG; // invalid timezone
 166             if (timezone == MAXLONG)
 167             {
 168                 TIME_ZONE_INFORMATION tzi;
 169                 ::GetTimeZoneInformation(&tzi);
 170                 timezone = tzi.Bias;
 171             }
 172             return timezone;
 173         }
 174         #define WX_TIMEZONE wxGetTimeZone()
 175         #else
 176         // Old method using _timezone: this symbol doesn't exist in the dynamic run-time library (i.e. using /MD)
 177         #define WX_TIMEZONE _timezone
 178         #endif
 179     #else // unknown platform - try timezone
 180         #define WX_TIMEZONE timezone
 181     #endif
 182 #endif // !WX_TIMEZONE && !WX_GMTOFF_IN_TM
 183
 184 // NB: VC8 safe time functions could/should be used for wxMSW as well probably
 185 #if defined(__WXWINCE__) && defined(__VISUALC8__)
 186
 187 struct tm *wxLocaltime_r(const time_t *t, struct tm* tm)
 188 {
 189     __time64_t t64 = *t;
 190     return _localtime64_s(tm, &t64) == 0 ? tm : NULL;
 191 }
 192
 193 struct tm *wxGmtime_r(const time_t* t, struct tm* tm)
 194 {
 195     __time64_t t64 = *t;
 196     return _gmtime64_s(tm, &t64) == 0 ? tm : NULL;
 197 }
 198
 199 #else // !wxWinCE with VC8
 200
 201 #if (!defined(HAVE_LOCALTIME_R) || !defined(HAVE_GMTIME_R)) && wxUSE_THREADS && !defined(__WINDOWS__)
 202 static wxMutex timeLock;
 203 #endif
 204
 205 #ifndef HAVE_LOCALTIME_R
 206 struct tm *wxLocaltime_r(const time_t* ticks, struct tm* temp)
 207 {
 208 #if wxUSE_THREADS && !defined(__WINDOWS__)
 209   // No need to waste time with a mutex on windows since it's using
 210   // thread local storage for localtime anyway.
 211   wxMutexLocker locker(timeLock);
 212 #endif
 213
 214   // Borland CRT crashes when passed 0 ticks for some reason, see SF bug 1704438
 215 #ifdef __BORLANDC__
 216   if ( !*ticks )
 217       return NULL;
 218 #endif
 219
 220   const tm * const t = localtime(ticks);
 221   if ( !t )
 222       return NULL;
 223
 224   memcpy(temp, t, sizeof(struct tm));
 225   return temp;
 226 }
 227 #endif // !HAVE_LOCALTIME_R
 228
 229 #ifndef HAVE_GMTIME_R
 230 struct tm *wxGmtime_r(const time_t* ticks, struct tm* temp)
 231 {
 232 #if wxUSE_THREADS && !defined(__WINDOWS__)
 233   // No need to waste time with a mutex on windows since it's
 234   // using thread local storage for gmtime anyway.
 235   wxMutexLocker locker(timeLock);
 236 #endif
 237
 238 #ifdef __BORLANDC__
 239   if ( !*ticks )
 240       return NULL;
 241 #endif
 242
 243   const tm * const t = gmtime(ticks);
 244   if ( !t )
 245       return NULL;
 246
 247   memcpy(temp, gmtime(ticks), sizeof(struct tm));
 248   return temp;
 249 }
 250 #endif // !HAVE_GMTIME_R
 251
 252 #endif // wxWinCE with VC8/other platforms
 253
 254 // ----------------------------------------------------------------------------
 255 // macros
 256 // ----------------------------------------------------------------------------
 257
 258 // debugging helper: just a convenient replacement of wxCHECK()
 259 #define wxDATETIME_CHECK(expr, msg) \
 260     wxCHECK2_MSG(expr, *this = wxInvalidDateTime; return *this, msg)
 261
 262 // ----------------------------------------------------------------------------
 263 // private classes
 264 // ----------------------------------------------------------------------------
 265
 266 class wxDateTimeHolidaysModule : public wxModule
 267 {
 268 public:
 269     virtual bool OnInit()
 270     {
 271         wxDateTimeHolidayAuthority::AddAuthority(new wxDateTimeWorkDays);
 272
 273         return true;
 274     }
 275
 276     virtual void OnExit()
 277     {
 278         wxDateTimeHolidayAuthority::ClearAllAuthorities();
 279         wxDateTimeHolidayAuthority::ms_authorities.clear();
 280     }
 281
 282 private:
 283     DECLARE_DYNAMIC_CLASS(wxDateTimeHolidaysModule)
 284 };
 285
 286 IMPLEMENT_DYNAMIC_CLASS(wxDateTimeHolidaysModule, wxModule)
 287
 288 // ----------------------------------------------------------------------------
 289 // constants
 290 // ----------------------------------------------------------------------------
 291
 292 // some trivial ones
 293 static const int MONTHS_IN_YEAR = 12;
 294
 295 static const int SEC_PER_MIN = 60;
 296
 297 static const int MIN_PER_HOUR = 60;
 298
 299 static const int HOURS_PER_DAY = 24;
 300
 301 static const long SECONDS_PER_DAY = 86400l;
 302
 303 static const int DAYS_PER_WEEK = 7;
 304
 305 static const long MILLISECONDS_PER_DAY = 86400000l;
 306
 307 // this is the integral part of JDN of the midnight of Jan 1, 1970
 308 // (i.e. JDN(Jan 1, 1970) = 2440587.5)
 309 static const long EPOCH_JDN = 2440587l;
 310
 311 // these values are only used in asserts so don't define them if asserts are
 312 // disabled to avoid warnings about unused static variables
 313 #if wxDEBUG_LEVEL
 314 // the date of JDN -0.5 (as we don't work with fractional parts, this is the
 315 // reference date for us) is Nov 24, 4714BC
 316 static const int JDN_0_YEAR = -4713;
 317 static const int JDN_0_MONTH = wxDateTime::Nov;
 318 static const int JDN_0_DAY = 24;
 319 #endif // wxDEBUG_LEVEL
 320
 321 // the constants used for JDN calculations
 322 static const long JDN_OFFSET         = 32046l;
 323 static const long DAYS_PER_5_MONTHS  = 153l;
 324 static const long DAYS_PER_4_YEARS   = 1461l;
 325 static const long DAYS_PER_400_YEARS = 146097l;
 326
 327 // this array contains the cumulated number of days in all previous months for
 328 // normal and leap years
 329 static const wxDateTime::wxDateTime_t gs_cumulatedDays[2][MONTHS_IN_YEAR] =
 330 {
 331     { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 },
 332     { 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335 }
 333 };
 334
 335 const long wxDateTime::TIME_T_FACTOR = 1000l;
 336
 337 // ----------------------------------------------------------------------------
 338 // global data
 339 // ----------------------------------------------------------------------------
 340
 341 const char *wxDefaultDateTimeFormat = "%c";
 342 const char *wxDefaultTimeSpanFormat = "%H:%M:%S";
 343
 344 // in the fine tradition of ANSI C we use our equivalent of (time_t)-1 to
 345 // indicate an invalid wxDateTime object
 346 const wxDateTime wxDefaultDateTime;
 347
 348 wxDateTime::Country wxDateTime::ms_country = wxDateTime::Country_Unknown;
 349
 350 // ----------------------------------------------------------------------------
 351 // private functions
 352 // ----------------------------------------------------------------------------
 353
 354 // debugger helper: this function can be called from a debugger to show what
 355 // the date really is
 356 extern const char *wxDumpDate(const wxDateTime* dt)
 357 {
 358     static char buf[128];
 359
 360     wxString fmt(dt->Format("%Y-%m-%d (%a) %H:%M:%S"));
 361     wxStrlcpy(buf,
 362               (fmt + " (" + dt->GetValue().ToString() + " ticks)").ToAscii(),
 363               WXSIZEOF(buf));
 364
 365     return buf;
 366 }
 367
 368 // get the number of days in the given month of the given year
 369 static inline
 370 wxDateTime::wxDateTime_t GetNumOfDaysInMonth(int year, wxDateTime::Month month)
 371 {
 372     // the number of days in month in Julian/Gregorian calendar: the first line
 373     // is for normal years, the second one is for the leap ones
 374     static wxDateTime::wxDateTime_t daysInMonth[2][MONTHS_IN_YEAR] =
 375     {
 376         { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
 377         { 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
 378     };
 379
 380     return daysInMonth[wxDateTime::IsLeapYear(year)][month];
 381 }
 382
 383 // returns the time zone in the C sense, i.e. the difference UTC - local
 384 // (in seconds)
 385 // NOTE: not static because used by datetimefmt.cpp
 386 int GetTimeZone()
 387 {
 388     // set to true when the timezone is set
 389     static bool s_timezoneSet = false;
 390     static long gmtoffset = LONG_MAX; // invalid timezone
 391
 392     // ensure that the timezone variable is set by calling wxLocaltime_r
 393     if ( !s_timezoneSet )
 394     {
 395         // just call wxLocaltime_r() instead of figuring out whether this
 396         // system supports tzset(), _tzset() or something else
 397         time_t t = 0;
 398         struct tm tm;
 399
 400         wxLocaltime_r(&t, &tm);
 401         s_timezoneSet = true;
 402
 403 #ifdef WX_GMTOFF_IN_TM
 404         // note that GMT offset is the opposite of time zone and so to return
 405         // consistent results in both WX_GMTOFF_IN_TM and !WX_GMTOFF_IN_TM
 406         // cases we have to negate it
 407         gmtoffset = -tm.tm_gmtoff;
 408 #else // !WX_GMTOFF_IN_TM
 409         gmtoffset = WX_TIMEZONE;
 410 #endif // WX_GMTOFF_IN_TM/!WX_GMTOFF_IN_TM
 411     }
 412
 413     return (int)gmtoffset;
 414 }
 415
 416 // return the integral part of the JDN for the midnight of the given date (to
 417 // get the real JDN you need to add 0.5, this is, in fact, JDN of the
 418 // noon of the previous day)
 419 static long GetTruncatedJDN(wxDateTime::wxDateTime_t day,
 420                             wxDateTime::Month mon,
 421                             int year)
 422 {
 423     // CREDIT: code below is by Scott E. Lee (but bugs are mine)
 424
 425     // check the date validity
 426     wxASSERT_MSG(
 427       (year > JDN_0_YEAR) ||
 428       ((year == JDN_0_YEAR) && (mon > JDN_0_MONTH)) ||
 429       ((year == JDN_0_YEAR) && (mon == JDN_0_MONTH) && (day >= JDN_0_DAY)),
 430       _T("date out of range - can't convert to JDN")
 431                 );
 432
 433     // make the year positive to avoid problems with negative numbers division
 434     year += 4800;
 435
 436     // months are counted from March here
 437     int month;
 438     if ( mon >= wxDateTime::Mar )
 439     {
 440         month = mon - 2;
 441     }
 442     else
 443     {
 444         month = mon + 10;
 445         year--;
 446     }
 447
 448     // now we can simply add all the contributions together
 449     return ((year / 100) * DAYS_PER_400_YEARS) / 4
 450             + ((year % 100) * DAYS_PER_4_YEARS) / 4
 451             + (month * DAYS_PER_5_MONTHS + 2) / 5
 452             + day
 453             - JDN_OFFSET;
 454 }
 455
 456 #ifdef HAVE_STRFTIME
 457
 458 // this function is a wrapper around strftime(3) adding error checking
 459 // NOTE: not static because used by datetimefmt.cpp
 460 wxString CallStrftime(const wxString& format, const tm* tm)
 461 {
 462     wxChar buf[4096];
 463     // Create temp wxString here to work around mingw/cygwin bug 1046059
 464     // http://sourceforge.net/tracker/?func=detail&atid=102435&aid=1046059&group_id=2435
 465     wxString s;
 466
 467     if ( !wxStrftime(buf, WXSIZEOF(buf), format, tm) )
 468     {
 469         // if the format is valid, buffer must be too small?
 470         wxFAIL_MSG(_T("strftime() failed"));
 471
 472         buf[0] = '\0';
 473     }
 474
 475     s = buf;
 476     return s;
 477 }
 478
 479 #endif // HAVE_STRFTIME
 480
 481 // if year and/or month have invalid values, replace them with the current ones
 482 static void ReplaceDefaultYearMonthWithCurrent(int *year,
 483                                                wxDateTime::Month *month)
 484 {
 485     struct tm *tmNow = NULL;
 486     struct tm tmstruct;
 487
 488     if ( *year == wxDateTime::Inv_Year )
 489     {
 490         tmNow = wxDateTime::GetTmNow(&tmstruct);
 491
 492         *year = 1900 + tmNow->tm_year;
 493     }
 494
 495     if ( *month == wxDateTime::Inv_Month )
 496     {
 497         if ( !tmNow )
 498             tmNow = wxDateTime::GetTmNow(&tmstruct);
 499
 500         *month = (wxDateTime::Month)tmNow->tm_mon;
 501     }
 502 }
 503
 504 // fill the struct tm with default values
 505 // NOTE: not static because used by datetimefmt.cpp
 506 void InitTm(struct tm& tm)
 507 {
 508     // struct tm may have etxra fields (undocumented and with unportable
 509     // names) which, nevertheless, must be set to 0
 510     memset(&tm, 0, sizeof(struct tm));
 511
 512     tm.tm_mday = 1;   // mday 0 is invalid
 513     tm.tm_year = 76;  // any valid year
 514     tm.tm_isdst = -1; // auto determine
 515 }
 516
 517 // ============================================================================
 518 // implementation of wxDateTime
 519 // ============================================================================
 520
 521 // ----------------------------------------------------------------------------
 522 // struct Tm
 523 // ----------------------------------------------------------------------------
 524
 525 wxDateTime::Tm::Tm()
 526 {
 527     year = (wxDateTime_t)wxDateTime::Inv_Year;
 528     mon = wxDateTime::Inv_Month;
 529     mday = 0;
 530     hour = min = sec = msec = 0;
 531     wday = wxDateTime::Inv_WeekDay;
 532 }
 533
 534 wxDateTime::Tm::Tm(const struct tm& tm, const TimeZone& tz)
 535               : m_tz(tz)
 536 {
 537     msec = 0;
 538     sec = (wxDateTime::wxDateTime_t)tm.tm_sec;
 539     min = (wxDateTime::wxDateTime_t)tm.tm_min;
 540     hour = (wxDateTime::wxDateTime_t)tm.tm_hour;
 541     mday = (wxDateTime::wxDateTime_t)tm.tm_mday;
 542     mon = (wxDateTime::Month)tm.tm_mon;
 543     year = 1900 + tm.tm_year;
 544     wday = (wxDateTime::wxDateTime_t)tm.tm_wday;
 545     yday = (wxDateTime::wxDateTime_t)tm.tm_yday;
 546 }
 547
 548 bool wxDateTime::Tm::IsValid() const
 549 {
 550     // we allow for the leap seconds, although we don't use them (yet)
 551     return (year != wxDateTime::Inv_Year) && (mon != wxDateTime::Inv_Month) &&
 552            (mday <= GetNumOfDaysInMonth(year, mon)) &&
 553            (hour < 24) && (min < 60) && (sec < 62) && (msec < 1000);
 554 }
 555
 556 void wxDateTime::Tm::ComputeWeekDay()
 557 {
 558     // compute the week day from day/month/year: we use the dumbest algorithm
 559     // possible: just compute our JDN and then use the (simple to derive)
 560     // formula: weekday = (JDN + 1.5) % 7
 561     wday = (wxDateTime::wxDateTime_t)((GetTruncatedJDN(mday, mon, year) + 2) % 7);
 562 }
 563
 564 void wxDateTime::Tm::AddMonths(int monDiff)
 565 {
 566     // normalize the months field
 567     while ( monDiff < -mon )
 568     {
 569         year--;
 570
 571         monDiff += MONTHS_IN_YEAR;
 572     }
 573
 574     while ( monDiff + mon >= MONTHS_IN_YEAR )
 575     {
 576         year++;
 577
 578         monDiff -= MONTHS_IN_YEAR;
 579     }
 580
 581     mon = (wxDateTime::Month)(mon + monDiff);
 582
 583     wxASSERT_MSG( mon >= 0 && mon < MONTHS_IN_YEAR, _T("logic error") );
 584
 585     // NB: we don't check here that the resulting date is valid, this function
 586     //     is private and the caller must check it if needed
 587 }
 588
 589 void wxDateTime::Tm::AddDays(int dayDiff)
 590 {
 591     // normalize the days field
 592     while ( dayDiff + mday < 1 )
 593     {
 594         AddMonths(-1);
 595
 596         dayDiff += GetNumOfDaysInMonth(year, mon);
 597     }
 598
 599     mday = (wxDateTime::wxDateTime_t)( mday + dayDiff );
 600     while ( mday > GetNumOfDaysInMonth(year, mon) )
 601     {
 602         mday -= GetNumOfDaysInMonth(year, mon);
 603
 604         AddMonths(1);
 605     }
 606
 607     wxASSERT_MSG( mday > 0 && mday <= GetNumOfDaysInMonth(year, mon),
 608                   _T("logic error") );
 609 }
 610
 611 // ----------------------------------------------------------------------------
 612 // class TimeZone
 613 // ----------------------------------------------------------------------------
 614
 615 wxDateTime::TimeZone::TimeZone(wxDateTime::TZ tz)
 616 {
 617     switch ( tz )
 618     {
 619         case wxDateTime::Local:
 620             // get the offset from C RTL: it returns the difference GMT-local
 621             // while we want to have the offset _from_ GMT, hence the '-'
 622             m_offset = -GetTimeZone();
 623             break;
 624
 625         case wxDateTime::GMT_12:
 626         case wxDateTime::GMT_11:
 627         case wxDateTime::GMT_10:
 628         case wxDateTime::GMT_9:
 629         case wxDateTime::GMT_8:
 630         case wxDateTime::GMT_7:
 631         case wxDateTime::GMT_6:
 632         case wxDateTime::GMT_5:
 633         case wxDateTime::GMT_4:
 634         case wxDateTime::GMT_3:
 635         case wxDateTime::GMT_2:
 636         case wxDateTime::GMT_1:
 637             m_offset = -3600*(wxDateTime::GMT0 - tz);
 638             break;
 639
 640         case wxDateTime::GMT0:
 641         case wxDateTime::GMT1:
 642         case wxDateTime::GMT2:
 643         case wxDateTime::GMT3:
 644         case wxDateTime::GMT4:
 645         case wxDateTime::GMT5:
 646         case wxDateTime::GMT6:
 647         case wxDateTime::GMT7:
 648         case wxDateTime::GMT8:
 649         case wxDateTime::GMT9:
 650         case wxDateTime::GMT10:
 651         case wxDateTime::GMT11:
 652         case wxDateTime::GMT12:
 653         case wxDateTime::GMT13:
 654             m_offset = 3600*(tz - wxDateTime::GMT0);
 655             break;
 656
 657         case wxDateTime::A_CST:
 658             // Central Standard Time in use in Australia = UTC + 9.5
 659             m_offset = 60l*(9*MIN_PER_HOUR + MIN_PER_HOUR/2);
 660             break;
 661
 662         default:
 663             wxFAIL_MSG( _T("unknown time zone") );
 664     }
 665 }
 666
 667 // ----------------------------------------------------------------------------
 668 // static functions
 669 // ----------------------------------------------------------------------------
 670
 671 /* static */
 672 struct tm *wxDateTime::GetTmNow(struct tm *tmstruct)
 673 {
 674     time_t t = GetTimeNow();
 675     return wxLocaltime_r(&t, tmstruct);
 676 }
 677
 678 /* static */
 679 bool wxDateTime::IsLeapYear(int year, wxDateTime::Calendar cal)
 680 {
 681     if ( year == Inv_Year )
 682         year = GetCurrentYear();
 683
 684     if ( cal == Gregorian )
 685     {
 686         // in Gregorian calendar leap years are those divisible by 4 except
 687         // those divisible by 100 unless they're also divisible by 400
 688         // (in some countries, like Russia and Greece, additional corrections
 689         // exist, but they won't manifest themselves until 2700)
 690         return (year % 4 == 0) && ((year % 100 != 0) || (year % 400 == 0));
 691     }
 692     else if ( cal == Julian )
 693     {
 694         // in Julian calendar the rule is simpler
 695         return year % 4 == 0;
 696     }
 697     else
 698     {
 699         wxFAIL_MSG(_T("unknown calendar"));
 700
 701         return false;
 702     }
 703 }
 704
 705 /* static */
 706 int wxDateTime::GetCentury(int year)
 707 {
 708     return year > 0 ? year / 100 : year / 100 - 1;
 709 }
 710
 711 /* static */
 712 int wxDateTime::ConvertYearToBC(int year)
 713 {
 714     // year 0 is BC 1
 715     return year > 0 ? year : year - 1;
 716 }
 717
 718 /* static */
 719 int wxDateTime::GetCurrentYear(wxDateTime::Calendar cal)
 720 {
 721     switch ( cal )
 722     {
 723         case Gregorian:
 724             return Now().GetYear();
 725
 726         case Julian:
 727             wxFAIL_MSG(_T("TODO"));
 728             break;
 729
 730         default:
 731             wxFAIL_MSG(_T("unsupported calendar"));
 732             break;
 733     }
 734
 735     return Inv_Year;
 736 }
 737
 738 /* static */
 739 wxDateTime::Month wxDateTime::GetCurrentMonth(wxDateTime::Calendar cal)
 740 {
 741     switch ( cal )
 742     {
 743         case Gregorian:
 744             return Now().GetMonth();
 745
 746         case Julian:
 747             wxFAIL_MSG(_T("TODO"));
 748             break;
 749
 750         default:
 751             wxFAIL_MSG(_T("unsupported calendar"));
 752             break;
 753     }
 754
 755     return Inv_Month;
 756 }
 757
 758 /* static */
 759 wxDateTime::wxDateTime_t wxDateTime::GetNumberOfDays(int year, Calendar cal)
 760 {
 761     if ( year == Inv_Year )
 762     {
 763         // take the current year if none given
 764         year = GetCurrentYear();
 765     }
 766
 767     switch ( cal )
 768     {
 769         case Gregorian:
 770         case Julian:
 771             return IsLeapYear(year) ? 366 : 365;
 772
 773         default:
 774             wxFAIL_MSG(_T("unsupported calendar"));
 775             break;
 776     }
 777
 778     return 0;
 779 }
 780
 781 /* static */
 782 wxDateTime::wxDateTime_t wxDateTime::GetNumberOfDays(wxDateTime::Month month,
 783                                                      int year,
 784                                                      wxDateTime::Calendar cal)
 785 {
 786     wxCHECK_MSG( month < MONTHS_IN_YEAR, 0, _T("invalid month") );
 787
 788     if ( cal == Gregorian || cal == Julian )
 789     {
 790         if ( year == Inv_Year )
 791         {
 792             // take the current year if none given
 793             year = GetCurrentYear();
 794         }
 795
 796         return GetNumOfDaysInMonth(year, month);
 797     }
 798     else
 799     {
 800         wxFAIL_MSG(_T("unsupported calendar"));
 801
 802         return 0;
 803     }
 804 }
 805
 806 /* static */
 807 wxString wxDateTime::GetMonthName(wxDateTime::Month month,
 808                                   wxDateTime::NameFlags flags)
 809 {
 810     wxCHECK_MSG( month != Inv_Month, wxEmptyString, _T("invalid month") );
 811 #ifdef HAVE_STRFTIME
 812     // notice that we must set all the fields to avoid confusing libc (GNU one
 813     // gets confused to a crash if we don't do this)
 814     tm tm;
 815     InitTm(tm);
 816     tm.tm_mon = month;
 817
 818     return CallStrftime(flags == Name_Abbr ? _T("%b") : _T("%B"), &tm);
 819 #else // !HAVE_STRFTIME
 820     wxString ret;
 821     switch(month)
 822     {
 823         case Jan:
 824             ret = (flags == Name_Abbr ? wxT("Jan"): wxT("January"));
 825             break;
 826         case Feb:
 827             ret = (flags == Name_Abbr ? wxT("Feb"): wxT("Febuary"));
 828             break;
 829         case Mar:
 830             ret = (flags == Name_Abbr ? wxT("Mar"): wxT("March"));
 831             break;
 832         case Apr:
 833             ret = (flags == Name_Abbr ? wxT("Apr"): wxT("April"));
 834             break;
 835         case May:
 836             ret = (flags == Name_Abbr ? wxT("May"): wxT("May"));
 837             break;
 838         case Jun:
 839             ret = (flags == Name_Abbr ? wxT("Jun"): wxT("June"));
 840             break;
 841         case Jul:
 842             ret = (flags == Name_Abbr ? wxT("Jul"): wxT("July"));
 843             break;
 844         case Aug:
 845             ret = (flags == Name_Abbr ? wxT("Aug"): wxT("August"));
 846             break;
 847         case Sep:
 848             ret = (flags == Name_Abbr ? wxT("Sep"): wxT("September"));
 849             break;
 850         case Oct:
 851             ret = (flags == Name_Abbr ? wxT("Oct"): wxT("October"));
 852             break;
 853         case Nov:
 854             ret = (flags == Name_Abbr ? wxT("Nov"): wxT("November"));
 855             break;
 856         case Dec:
 857             ret = (flags == Name_Abbr ? wxT("Dec"): wxT("December"));
 858             break;
 859     }
 860     return ret;
 861 #endif // HAVE_STRFTIME/!HAVE_STRFTIME
 862 }
 863
 864 /* static */
 865 wxString wxDateTime::GetWeekDayName(wxDateTime::WeekDay wday,
 866                                     wxDateTime::NameFlags flags)
 867 {
 868     wxCHECK_MSG( wday != Inv_WeekDay, wxEmptyString, _T("invalid weekday") );
 869 #ifdef HAVE_STRFTIME
 870     // take some arbitrary Sunday (but notice that the day should be such that
 871     // after adding wday to it below we still have a valid date, e.g. don't
 872     // take 28 here!)
 873     tm tm;
 874     InitTm(tm);
 875     tm.tm_mday = 21;
 876     tm.tm_mon = Nov;
 877     tm.tm_year = 99;
 878
 879     // and offset it by the number of days needed to get the correct wday
 880     tm.tm_mday += wday;
 881
 882     // call mktime() to normalize it...
 883     (void)mktime(&tm);
 884
 885     // ... and call strftime()
 886     return CallStrftime(flags == Name_Abbr ? _T("%a") : _T("%A"), &tm);
 887 #else // !HAVE_STRFTIME
 888     wxString ret;
 889     switch(wday)
 890     {
 891         case Sun:
 892             ret = (flags == Name_Abbr ? wxT("Sun") : wxT("Sunday"));
 893             break;
 894         case Mon:
 895             ret = (flags == Name_Abbr ? wxT("Mon") : wxT("Monday"));
 896             break;
 897         case Tue:
 898             ret = (flags == Name_Abbr ? wxT("Tue") : wxT("Tuesday"));
 899             break;
 900         case Wed:
 901             ret = (flags == Name_Abbr ? wxT("Wed") : wxT("Wednesday"));
 902             break;
 903         case Thu:
 904             ret = (flags == Name_Abbr ? wxT("Thu") : wxT("Thursday"));
 905             break;
 906         case Fri:
 907             ret = (flags == Name_Abbr ? wxT("Fri") : wxT("Friday"));
 908             break;
 909         case Sat:
 910             ret = (flags == Name_Abbr ? wxT("Sat") : wxT("Saturday"));
 911             break;
 912     }
 913     return ret;
 914 #endif // HAVE_STRFTIME/!HAVE_STRFTIME
 915 }
 916
 917 /* static */
 918 void wxDateTime::GetAmPmStrings(wxString *am, wxString *pm)
 919 {
 920     tm tm;
 921     InitTm(tm);
 922     wxChar buffer[64];
 923     // @Note: Do not call 'CallStrftime' here! CallStrftime checks the return code
 924     // and causes an assertion failed if the buffer is to small (which is good) - OR -
 925     // if strftime does not return anything because the format string is invalid - OR -
 926     // if there are no 'am' / 'pm' tokens defined for the current locale (which is not good).
 927     // wxDateTime::ParseTime will try several different formats to parse the time.
 928     // As a result, GetAmPmStrings might get called, even if the current locale
 929     // does not define any 'am' / 'pm' tokens. In this case, wxStrftime would
 930     // assert, even though it is a perfectly legal use.
 931     if ( am )
 932     {
 933         if (wxStrftime(buffer, sizeof(buffer)/sizeof(wxChar), _T("%p"), &tm) > 0)
 934             *am = wxString(buffer);
 935         else
 936             *am = wxString();
 937     }
 938     if ( pm )
 939     {
 940         tm.tm_hour = 13;
 941         if (wxStrftime(buffer, sizeof(buffer)/sizeof(wxChar), _T("%p"), &tm) > 0)
 942             *pm = wxString(buffer);
 943         else
 944             *pm = wxString();
 945     }
 946 }
 947
 948
 949 // ----------------------------------------------------------------------------
 950 // Country stuff: date calculations depend on the country (DST, work days,
 951 // ...), so we need to know which rules to follow.
 952 // ----------------------------------------------------------------------------
 953
 954 /* static */
 955 wxDateTime::Country wxDateTime::GetCountry()
 956 {
 957     // TODO use LOCALE_ICOUNTRY setting under Win32
 958 #ifndef __WXWINCE__
 959     if ( ms_country == Country_Unknown )
 960     {
 961         // try to guess from the time zone name
 962         time_t t = time(NULL);
 963         struct tm tmstruct;
 964         struct tm *tm = wxLocaltime_r(&t, &tmstruct);
 965
 966         wxString tz = CallStrftime(_T("%Z"), tm);
 967         if ( tz == _T("WET") || tz == _T("WEST") )
 968         {
 969             ms_country = UK;
 970         }
 971         else if ( tz == _T("CET") || tz == _T("CEST") )
 972         {
 973             ms_country = Country_EEC;
 974         }
 975         else if ( tz == _T("MSK") || tz == _T("MSD") )
 976         {
 977             ms_country = Russia;
 978         }
 979         else if ( tz == _T("AST") || tz == _T("ADT") ||
 980                   tz == _T("EST") || tz == _T("EDT") ||
 981                   tz == _T("CST") || tz == _T("CDT") ||
 982                   tz == _T("MST") || tz == _T("MDT") ||
 983                   tz == _T("PST") || tz == _T("PDT") )
 984         {
 985             ms_country = USA;
 986         }
 987         else
 988         {
 989             // well, choose a default one
 990             ms_country = USA;
 991         }
 992     }
 993 #else // __WXWINCE__
 994      ms_country = USA;
 995 #endif // !__WXWINCE__/__WXWINCE__
 996
 997     return ms_country;
 998 }
 999
1000 /* static */
1001 void wxDateTime::SetCountry(wxDateTime::Country country)
1002 {
1003     ms_country = country;
1004 }
1005
1006 /* static */
1007 bool wxDateTime::IsWestEuropeanCountry(Country country)
1008 {
1009     if ( country == Country_Default )
1010     {
1011         country = GetCountry();
1012     }
1013
1014     return (Country_WesternEurope_Start <= country) &&
1015            (country <= Country_WesternEurope_End);
1016 }
1017
1018 // ----------------------------------------------------------------------------
1019 // DST calculations: we use 3 different rules for the West European countries,
1020 // USA and for the rest of the world. This is undoubtedly false for many
1021 // countries, but I lack the necessary info (and the time to gather it),
1022 // please add the other rules here!
1023 // ----------------------------------------------------------------------------
1024
1025 /* static */
1026 bool wxDateTime::IsDSTApplicable(int year, Country country)
1027 {
1028     if ( year == Inv_Year )
1029     {
1030         // take the current year if none given
1031         year = GetCurrentYear();
1032     }
1033
1034     if ( country == Country_Default )
1035     {
1036         country = GetCountry();
1037     }
1038
1039     switch ( country )
1040     {
1041         case USA:
1042         case UK:
1043             // DST was first observed in the US and UK during WWI, reused
1044             // during WWII and used again since 1966
1045             return year >= 1966 ||
1046                    (year >= 1942 && year <= 1945) ||
1047                    (year == 1918 || year == 1919);
1048
1049         default:
1050             // assume that it started after WWII
1051             return year > 1950;
1052     }
1053 }
1054
1055 /* static */
1056 wxDateTime wxDateTime::GetBeginDST(int year, Country country)
1057 {
1058     if ( year == Inv_Year )
1059     {
1060         // take the current year if none given
1061         year = GetCurrentYear();
1062     }
1063
1064     if ( country == Country_Default )
1065     {
1066         country = GetCountry();
1067     }
1068
1069     if ( !IsDSTApplicable(year, country) )
1070     {
1071         return wxInvalidDateTime;
1072     }
1073
1074     wxDateTime dt;
1075
1076     if ( IsWestEuropeanCountry(country) || (country == Russia) )
1077     {
1078         // DST begins at 1 a.m. GMT on the last Sunday of March
1079         if ( !dt.SetToLastWeekDay(Sun, Mar, year) )
1080         {
1081             // weird...
1082             wxFAIL_MSG( _T("no last Sunday in March?") );
1083         }
1084
1085         dt += wxTimeSpan::Hours(1);
1086     }
1087     else switch ( country )
1088     {
1089         case USA:
1090             switch ( year )
1091             {
1092                 case 1918:
1093                 case 1919:
1094                     // don't know for sure - assume it was in effect all year
1095
1096                 case 1943:
1097                 case 1944:
1098                 case 1945:
1099                     dt.Set(1, Jan, year);
1100                     break;
1101
1102                 case 1942:
1103                     // DST was installed Feb 2, 1942 by the Congress
1104                     dt.Set(2, Feb, year);
1105                     break;
1106
1107                     // Oil embargo changed the DST period in the US
1108                 case 1974:
1109                     dt.Set(6, Jan, 1974);
1110                     break;
1111
1112                 case 1975:
1113                     dt.Set(23, Feb, 1975);
1114                     break;
1115
1116                 default:
1117                     // before 1986, DST begun on the last Sunday of April, but
1118                     // in 1986 Reagan changed it to begin at 2 a.m. of the
1119                     // first Sunday in April
1120                     if ( year < 1986 )
1121                     {
1122                         if ( !dt.SetToLastWeekDay(Sun, Apr, year) )
1123                         {
1124                             // weird...
1125                             wxFAIL_MSG( _T("no first Sunday in April?") );
1126                         }
1127                     }
1128                     else if ( year > 2006 )
1129                     // Energy Policy Act of 2005, Pub. L. no. 109-58, 119 Stat 594 (2005).
1130                     // Starting in 2007, daylight time begins in the United States on the
1131                     // second Sunday in March and ends on the first Sunday in November
1132                     {
1133                         if ( !dt.SetToWeekDay(Sun, 2, Mar, year) )
1134                         {
1135                             // weird...
1136                             wxFAIL_MSG( _T("no second Sunday in March?") );
1137                         }
1138                     }
1139                     else
1140                     {
1141                         if ( !dt.SetToWeekDay(Sun, 1, Apr, year) )
1142                         {
1143                             // weird...
1144                             wxFAIL_MSG( _T("no first Sunday in April?") );
1145                         }
1146                     }
1147
1148                     dt += wxTimeSpan::Hours(2);
1149
1150                     // TODO what about timezone??
1151             }
1152
1153             break;
1154
1155         default:
1156             // assume Mar 30 as the start of the DST for the rest of the world
1157             // - totally bogus, of course
1158             dt.Set(30, Mar, year);
1159     }
1160
1161     return dt;
1162 }
1163
1164 /* static */
1165 wxDateTime wxDateTime::GetEndDST(int year, Country country)
1166 {
1167     if ( year == Inv_Year )
1168     {
1169         // take the current year if none given
1170         year = GetCurrentYear();
1171     }
1172
1173     if ( country == Country_Default )
1174     {
1175         country = GetCountry();
1176     }
1177
1178     if ( !IsDSTApplicable(year, country) )
1179     {
1180         return wxInvalidDateTime;
1181     }
1182
1183     wxDateTime dt;
1184
1185     if ( IsWestEuropeanCountry(country) || (country == Russia) )
1186     {
1187         // DST ends at 1 a.m. GMT on the last Sunday of October
1188         if ( !dt.SetToLastWeekDay(Sun, Oct, year) )
1189         {
1190             // weirder and weirder...
1191             wxFAIL_MSG( _T("no last Sunday in October?") );
1192         }
1193
1194         dt += wxTimeSpan::Hours(1);
1195     }
1196     else switch ( country )
1197     {
1198         case USA:
1199             switch ( year )
1200             {
1201                 case 1918:
1202                 case 1919:
1203                     // don't know for sure - assume it was in effect all year
1204
1205                 case 1943:
1206                 case 1944:
1207                     dt.Set(31, Dec, year);
1208                     break;
1209
1210                 case 1945:
1211                     // the time was reset after the end of the WWII
1212                     dt.Set(30, Sep, year);
1213                     break;
1214
1215                 default: // default for switch (year)
1216                     if ( year > 2006 )
1217                       // Energy Policy Act of 2005, Pub. L. no. 109-58, 119 Stat 594 (2005).
1218                       // Starting in 2007, daylight time begins in the United States on the
1219                       // second Sunday in March and ends on the first Sunday in November
1220                     {
1221                         if ( !dt.SetToWeekDay(Sun, 1, Nov, year) )
1222                         {
1223                             // weird...
1224                             wxFAIL_MSG( _T("no first Sunday in November?") );
1225                         }
1226                     }
1227                     else
1228                      // pre-2007
1229                      // DST ends at 2 a.m. on the last Sunday of October
1230                     {
1231                         if ( !dt.SetToLastWeekDay(Sun, Oct, year) )
1232                         {
1233                             // weirder and weirder...
1234                             wxFAIL_MSG( _T("no last Sunday in October?") );
1235                         }
1236                     }
1237
1238                     dt += wxTimeSpan::Hours(2);
1239
1240             // TODO: what about timezone??
1241             }
1242             break;
1243
1244         default: // default for switch (country)
1245             // assume October 26th as the end of the DST - totally bogus too
1246             dt.Set(26, Oct, year);
1247     }
1248
1249     return dt;
1250 }
1251
1252 // ----------------------------------------------------------------------------
1253 // constructors and assignment operators
1254 // ----------------------------------------------------------------------------
1255
1256 // return the current time with ms precision
1257 /* static */ wxDateTime wxDateTime::UNow()
1258 {
1259     return wxDateTime(wxGetLocalTimeMillis());
1260 }
1261
1262 // the values in the tm structure contain the local time
1263 wxDateTime& wxDateTime::Set(const struct tm& tm)
1264 {
1265     struct tm tm2(tm);
1266     time_t timet = mktime(&tm2);
1267
1268     if ( timet == (time_t)-1 )
1269     {
1270         // mktime() rather unintuitively fails for Jan 1, 1970 if the hour is
1271         // less than timezone - try to make it work for this case
1272         if ( tm2.tm_year == 70 && tm2.tm_mon == 0 && tm2.tm_mday == 1 )
1273         {
1274             return Set((time_t)(
1275                        GetTimeZone() +
1276                        tm2.tm_hour * MIN_PER_HOUR * SEC_PER_MIN +
1277                        tm2.tm_min * SEC_PER_MIN +
1278                        tm2.tm_sec));
1279         }
1280
1281         wxFAIL_MSG( _T("mktime() failed") );
1282
1283         *this = wxInvalidDateTime;
1284
1285         return *this;
1286     }
1287     else
1288     {
1289         return Set(timet);
1290     }
1291 }
1292
1293 wxDateTime& wxDateTime::Set(wxDateTime_t hour,
1294                             wxDateTime_t minute,
1295                             wxDateTime_t second,
1296                             wxDateTime_t millisec)
1297 {
1298     // we allow seconds to be 61 to account for the leap seconds, even if we
1299     // don't use them really
1300     wxDATETIME_CHECK( hour < 24 &&
1301                       second < 62 &&
1302                       minute < 60 &&
1303                       millisec < 1000,
1304                       _T("Invalid time in wxDateTime::Set()") );
1305
1306     // get the current date from system
1307     struct tm tmstruct;
1308     struct tm *tm = GetTmNow(&tmstruct);
1309
1310     wxDATETIME_CHECK( tm, _T("wxLocaltime_r() failed") );
1311
1312     // make a copy so it isn't clobbered by the call to mktime() below
1313     struct tm tm1(*tm);
1314
1315     // adjust the time
1316     tm1.tm_hour = hour;
1317     tm1.tm_min = minute;
1318     tm1.tm_sec = second;
1319
1320     // and the DST in case it changes on this date
1321     struct tm tm2(tm1);
1322     mktime(&tm2);
1323     if ( tm2.tm_isdst != tm1.tm_isdst )
1324         tm1.tm_isdst = tm2.tm_isdst;
1325
1326     (void)Set(tm1);
1327
1328     // and finally adjust milliseconds
1329     return SetMillisecond(millisec);
1330 }
1331
1332 wxDateTime& wxDateTime::Set(wxDateTime_t day,
1333                             Month        month,
1334                             int          year,
1335                             wxDateTime_t hour,
1336                             wxDateTime_t minute,
1337                             wxDateTime_t second,
1338                             wxDateTime_t millisec)
1339 {
1340     wxDATETIME_CHECK( hour < 24 &&
1341                       second < 62 &&
1342                       minute < 60 &&
1343                       millisec < 1000,
1344                       _T("Invalid time in wxDateTime::Set()") );
1345
1346     ReplaceDefaultYearMonthWithCurrent(&year, &month);
1347
1348     wxDATETIME_CHECK( (0 < day) && (day <= GetNumberOfDays(month, year)),
1349                       _T("Invalid date in wxDateTime::Set()") );
1350
1351     // the range of time_t type (inclusive)
1352     static const int yearMinInRange = 1970;
1353     static const int yearMaxInRange = 2037;
1354
1355     // test only the year instead of testing for the exact end of the Unix
1356     // time_t range - it doesn't bring anything to do more precise checks
1357     if ( year >= yearMinInRange && year <= yearMaxInRange )
1358     {
1359         // use the standard library version if the date is in range - this is
1360         // probably more efficient than our code
1361         struct tm tm;
1362         tm.tm_year = year - 1900;
1363         tm.tm_mon = month;
1364         tm.tm_mday = day;
1365         tm.tm_hour = hour;
1366         tm.tm_min = minute;
1367         tm.tm_sec = second;
1368         tm.tm_isdst = -1;       // mktime() will guess it
1369
1370         (void)Set(tm);
1371
1372         // and finally adjust milliseconds
1373         if (IsValid())
1374             SetMillisecond(millisec);
1375
1376         return *this;
1377     }
1378     else
1379     {
1380         // do time calculations ourselves: we want to calculate the number of
1381         // milliseconds between the given date and the epoch
1382
1383         // get the JDN for the midnight of this day
1384         m_time = GetTruncatedJDN(day, month, year);
1385         m_time -= EPOCH_JDN;
1386         m_time *= SECONDS_PER_DAY * TIME_T_FACTOR;
1387
1388         // JDN corresponds to GMT, we take localtime
1389         Add(wxTimeSpan(hour, minute, second + GetTimeZone(), millisec));
1390     }
1391
1392     return *this;
1393 }
1394
1395 wxDateTime& wxDateTime::Set(double jdn)
1396 {
1397     // so that m_time will be 0 for the midnight of Jan 1, 1970 which is jdn
1398     // EPOCH_JDN + 0.5
1399     jdn -= EPOCH_JDN + 0.5;
1400
1401     m_time.Assign(jdn*MILLISECONDS_PER_DAY);
1402
1403     // JDNs always are in UTC, so we don't need any adjustments for time zone
1404
1405     return *this;
1406 }
1407
1408 wxDateTime& wxDateTime::ResetTime()
1409 {
1410     Tm tm = GetTm();
1411
1412     if ( tm.hour || tm.min || tm.sec || tm.msec )
1413     {
1414         tm.msec =
1415         tm.sec =
1416         tm.min =
1417         tm.hour = 0;
1418
1419         Set(tm);
1420     }
1421
1422     return *this;
1423 }
1424
1425 wxDateTime wxDateTime::GetDateOnly() const
1426 {
1427     Tm tm = GetTm();
1428     tm.msec =
1429     tm.sec =
1430     tm.min =
1431     tm.hour = 0;
1432     return wxDateTime(tm);
1433 }
1434
1435 // ----------------------------------------------------------------------------
1436 // DOS Date and Time Format functions
1437 // ----------------------------------------------------------------------------
1438 // the dos date and time value is an unsigned 32 bit value in the format:
1439 // YYYYYYYMMMMDDDDDhhhhhmmmmmmsssss
1440 //
1441 // Y = year offset from 1980 (0-127)
1442 // M = month (1-12)
1443 // D = day of month (1-31)
1444 // h = hour (0-23)
1445 // m = minute (0-59)
1446 // s = bisecond (0-29) each bisecond indicates two seconds
1447 // ----------------------------------------------------------------------------
1448
1449 wxDateTime& wxDateTime::SetFromDOS(unsigned long ddt)
1450 {
1451     struct tm tm;
1452     InitTm(tm);
1453
1454     long year = ddt & 0xFE000000;
1455     year >>= 25;
1456     year += 80;
1457     tm.tm_year = year;
1458
1459     long month = ddt & 0x1E00000;
1460     month >>= 21;
1461     month -= 1;
1462     tm.tm_mon = month;
1463
1464     long day = ddt & 0x1F0000;
1465     day >>= 16;
1466     tm.tm_mday = day;
1467
1468     long hour = ddt & 0xF800;
1469     hour >>= 11;
1470     tm.tm_hour = hour;
1471
1472     long minute = ddt & 0x7E0;
1473     minute >>= 5;
1474     tm.tm_min = minute;
1475
1476     long second = ddt & 0x1F;
1477     tm.tm_sec = second * 2;
1478
1479     return Set(mktime(&tm));
1480 }
1481
1482 unsigned long wxDateTime::GetAsDOS() const
1483 {
1484     unsigned long ddt;
1485     time_t ticks = GetTicks();
1486     struct tm tmstruct;
1487     struct tm *tm = wxLocaltime_r(&ticks, &tmstruct);
1488     wxCHECK_MSG( tm, ULONG_MAX, _T("time can't be represented in DOS format") );
1489
1490     long year = tm->tm_year;
1491     year -= 80;
1492     year <<= 25;
1493
1494     long month = tm->tm_mon;
1495     month += 1;
1496     month <<= 21;
1497
1498     long day = tm->tm_mday;
1499     day <<= 16;
1500
1501     long hour = tm->tm_hour;
1502     hour <<= 11;
1503
1504     long minute = tm->tm_min;
1505     minute <<= 5;
1506
1507     long second = tm->tm_sec;
1508     second /= 2;
1509
1510     ddt = year | month | day | hour | minute | second;
1511     return ddt;
1512 }
1513
1514 // ----------------------------------------------------------------------------
1515 // time_t <-> broken down time conversions
1516 // ----------------------------------------------------------------------------
1517
1518 wxDateTime::Tm wxDateTime::GetTm(const TimeZone& tz) const
1519 {
1520     wxASSERT_MSG( IsValid(), _T("invalid wxDateTime") );
1521
1522     time_t time = GetTicks();
1523     if ( time != (time_t)-1 )
1524     {
1525         // use C RTL functions
1526         struct tm tmstruct;
1527         tm *tm;
1528         if ( tz.GetOffset() == -GetTimeZone() )
1529         {
1530             // we are working with local time
1531             tm = wxLocaltime_r(&time, &tmstruct);
1532
1533             // should never happen
1534             wxCHECK_MSG( tm, Tm(), _T("wxLocaltime_r() failed") );
1535         }
1536         else
1537         {
1538             time += (time_t)tz.GetOffset();
1539 #if defined(__VMS__) || defined(__WATCOMC__) // time is unsigned so avoid warning
1540             int time2 = (int) time;
1541             if ( time2 >= 0 )
1542 #else
1543             if ( time >= 0 )
1544 #endif
1545             {
1546                 tm = wxGmtime_r(&time, &tmstruct);
1547
1548                 // should never happen
1549                 wxCHECK_MSG( tm, Tm(), _T("wxGmtime_r() failed") );
1550             }
1551             else
1552             {
1553                 tm = (struct tm *)NULL;
1554             }
1555         }
1556
1557         if ( tm )
1558         {
1559             // adjust the milliseconds
1560             Tm tm2(*tm, tz);
1561             long timeOnly = (m_time % MILLISECONDS_PER_DAY).ToLong();
1562             tm2.msec = (wxDateTime_t)(timeOnly % 1000);
1563             return tm2;
1564         }
1565         //else: use generic code below
1566     }
1567
1568     // remember the time and do the calculations with the date only - this
1569     // eliminates rounding errors of the floating point arithmetics
1570
1571     wxLongLong timeMidnight = m_time + tz.GetOffset() * 1000;
1572
1573     long timeOnly = (timeMidnight % MILLISECONDS_PER_DAY).ToLong();
1574
1575     // we want to always have positive time and timeMidnight to be really
1576     // the midnight before it
1577     if ( timeOnly < 0 )
1578     {
1579         timeOnly = MILLISECONDS_PER_DAY + timeOnly;
1580     }
1581
1582     timeMidnight -= timeOnly;
1583
1584     // calculate the Gregorian date from JDN for the midnight of our date:
1585     // this will yield day, month (in 1..12 range) and year
1586
1587     // actually, this is the JDN for the noon of the previous day
1588     long jdn = (timeMidnight / MILLISECONDS_PER_DAY).ToLong() + EPOCH_JDN;
1589
1590     // CREDIT: code below is by Scott E. Lee (but bugs are mine)
1591
1592     wxASSERT_MSG( jdn > -2, _T("JDN out of range") );
1593
1594     // calculate the century
1595     long temp = (jdn + JDN_OFFSET) * 4 - 1;
1596     long century = temp / DAYS_PER_400_YEARS;
1597
1598     // then the year and day of year (1 <= dayOfYear <= 366)
1599     temp = ((temp % DAYS_PER_400_YEARS) / 4) * 4 + 3;
1600     long year = (century * 100) + (temp / DAYS_PER_4_YEARS);
1601     long dayOfYear = (temp % DAYS_PER_4_YEARS) / 4 + 1;
1602
1603     // and finally the month and day of the month
1604     temp = dayOfYear * 5 - 3;
1605     long month = temp / DAYS_PER_5_MONTHS;
1606     long day = (temp % DAYS_PER_5_MONTHS) / 5 + 1;
1607
1608     // month is counted from March - convert to normal
1609     if ( month < 10 )
1610     {
1611         month += 3;
1612     }
1613     else
1614     {
1615         year += 1;
1616         month -= 9;
1617     }
1618
1619     // year is offset by 4800
1620     year -= 4800;
1621
1622     // check that the algorithm gave us something reasonable
1623     wxASSERT_MSG( (0 < month) && (month <= 12), _T("invalid month") );
1624     wxASSERT_MSG( (1 <= day) && (day < 32), _T("invalid day") );
1625
1626     // construct Tm from these values
1627     Tm tm;
1628     tm.year = (int)year;
1629     tm.mon = (Month)(month - 1); // algorithm yields 1 for January, not 0
1630     tm.mday = (wxDateTime_t)day;
1631     tm.msec = (wxDateTime_t)(timeOnly % 1000);
1632     timeOnly -= tm.msec;
1633     timeOnly /= 1000;               // now we have time in seconds
1634
1635     tm.sec = (wxDateTime_t)(timeOnly % SEC_PER_MIN);
1636     timeOnly -= tm.sec;
1637     timeOnly /= SEC_PER_MIN;        // now we have time in minutes
1638
1639     tm.min = (wxDateTime_t)(timeOnly % MIN_PER_HOUR);
1640     timeOnly -= tm.min;
1641
1642     tm.hour = (wxDateTime_t)(timeOnly / MIN_PER_HOUR);
1643
1644     return tm;
1645 }
1646
1647 wxDateTime& wxDateTime::SetYear(int year)
1648 {
1649     wxASSERT_MSG( IsValid(), _T("invalid wxDateTime") );
1650
1651     Tm tm(GetTm());
1652     tm.year = year;
1653     Set(tm);
1654
1655     return *this;
1656 }
1657
1658 wxDateTime& wxDateTime::SetMonth(Month month)
1659 {
1660     wxASSERT_MSG( IsValid(), _T("invalid wxDateTime") );
1661
1662     Tm tm(GetTm());
1663     tm.mon = month;
1664     Set(tm);
1665
1666     return *this;
1667 }
1668
1669 wxDateTime& wxDateTime::SetDay(wxDateTime_t mday)
1670 {
1671     wxASSERT_MSG( IsValid(), _T("invalid wxDateTime") );
1672
1673     Tm tm(GetTm());
1674     tm.mday = mday;
1675     Set(tm);
1676
1677     return *this;
1678 }
1679
1680 wxDateTime& wxDateTime::SetHour(wxDateTime_t hour)
1681 {
1682     wxASSERT_MSG( IsValid(), _T("invalid wxDateTime") );
1683
1684     Tm tm(GetTm());
1685     tm.hour = hour;
1686     Set(tm);
1687
1688     return *this;
1689 }
1690
1691 wxDateTime& wxDateTime::SetMinute(wxDateTime_t min)
1692 {
1693     wxASSERT_MSG( IsValid(), _T("invalid wxDateTime") );
1694
1695     Tm tm(GetTm());
1696     tm.min = min;
1697     Set(tm);
1698
1699     return *this;
1700 }
1701
1702 wxDateTime& wxDateTime::SetSecond(wxDateTime_t sec)
1703 {
1704     wxASSERT_MSG( IsValid(), _T("invalid wxDateTime") );
1705
1706     Tm tm(GetTm());
1707     tm.sec = sec;
1708     Set(tm);
1709
1710     return *this;
1711 }
1712
1713 wxDateTime& wxDateTime::SetMillisecond(wxDateTime_t millisecond)
1714 {
1715     wxASSERT_MSG( IsValid(), _T("invalid wxDateTime") );
1716
1717     // we don't need to use GetTm() for this one
1718     m_time -= m_time % 1000l;
1719     m_time += millisecond;
1720
1721     return *this;
1722 }
1723
1724 // ----------------------------------------------------------------------------
1725 // wxDateTime arithmetics
1726 // ----------------------------------------------------------------------------
1727
1728 wxDateTime& wxDateTime::Add(const wxDateSpan& diff)
1729 {
1730     Tm tm(GetTm());
1731
1732     tm.year += diff.GetYears();
1733     tm.AddMonths(diff.GetMonths());
1734
1735     // check that the resulting date is valid
1736     if ( tm.mday > GetNumOfDaysInMonth(tm.year, tm.mon) )
1737     {
1738         // We suppose that when adding one month to Jan 31 we want to get Feb
1739         // 28 (or 29), i.e. adding a month to the last day of the month should
1740         // give the last day of the next month which is quite logical.
1741         //
1742         // Unfortunately, there is no logic way to understand what should
1743         // Jan 30 + 1 month be - Feb 28 too or Feb 27 (assuming non leap year)?
1744         // We make it Feb 28 (last day too), but it is highly questionable.
1745         tm.mday = GetNumOfDaysInMonth(tm.year, tm.mon);
1746     }
1747
1748     tm.AddDays(diff.GetTotalDays());
1749
1750     Set(tm);
1751
1752     wxASSERT_MSG( IsSameTime(tm),
1753                   _T("Add(wxDateSpan) shouldn't modify time") );
1754
1755     return *this;
1756 }
1757
1758 // ----------------------------------------------------------------------------
1759 // Weekday and monthday stuff
1760 // ----------------------------------------------------------------------------
1761
1762 // convert Sun, Mon, ..., Sat into 6, 0, ..., 5
1763 static inline int ConvertWeekDayToMondayBase(int wd)
1764 {
1765     return wd == wxDateTime::Sun ? 6 : wd - 1;
1766 }
1767
1768 /* static */
1769 wxDateTime
1770 wxDateTime::SetToWeekOfYear(int year, wxDateTime_t numWeek, WeekDay wd)
1771 {
1772     wxASSERT_MSG( numWeek > 0,
1773                   _T("invalid week number: weeks are counted from 1") );
1774
1775     // Jan 4 always lies in the 1st week of the year
1776     wxDateTime dt(4, Jan, year);
1777     dt.SetToWeekDayInSameWeek(wd);
1778     dt += wxDateSpan::Weeks(numWeek - 1);
1779
1780     return dt;
1781 }
1782
1783 #if WXWIN_COMPATIBILITY_2_6
1784 // use a separate function to avoid warnings about using deprecated
1785 // SetToTheWeek in GetWeek below
1786 static wxDateTime
1787 SetToTheWeek(int year,
1788              wxDateTime::wxDateTime_t numWeek,
1789              wxDateTime::WeekDay weekday,
1790              wxDateTime::WeekFlags flags)
1791 {
1792     // Jan 4 always lies in the 1st week of the year
1793     wxDateTime dt(4, wxDateTime::Jan, year);
1794     dt.SetToWeekDayInSameWeek(weekday, flags);
1795     dt += wxDateSpan::Weeks(numWeek - 1);
1796
1797     return dt;
1798 }
1799
1800 bool wxDateTime::SetToTheWeek(wxDateTime_t numWeek,
1801                               WeekDay weekday,
1802                               WeekFlags flags)
1803 {
1804     int year = GetYear();
1805     *this = ::SetToTheWeek(year, numWeek, weekday, flags);
1806     if ( GetYear() != year )
1807     {
1808         // oops... numWeek was too big
1809         return false;
1810     }
1811
1812     return true;
1813 }
1814
1815 wxDateTime wxDateTime::GetWeek(wxDateTime_t numWeek,
1816                                WeekDay weekday,
1817                                WeekFlags flags) const
1818 {
1819     return ::SetToTheWeek(GetYear(), numWeek, weekday, flags);
1820 }
1821 #endif // WXWIN_COMPATIBILITY_2_6
1822
1823 wxDateTime& wxDateTime::SetToLastMonthDay(Month month,
1824                                           int year)
1825 {
1826     // take the current month/year if none specified
1827     if ( year == Inv_Year )
1828         year = GetYear();
1829     if ( month == Inv_Month )
1830         month = GetMonth();
1831
1832     return Set(GetNumOfDaysInMonth(year, month), month, year);
1833 }
1834
1835 wxDateTime& wxDateTime::SetToWeekDayInSameWeek(WeekDay weekday, WeekFlags flags)
1836 {
1837     wxDATETIME_CHECK( weekday != Inv_WeekDay, _T("invalid weekday") );
1838
1839     int wdayDst = weekday,
1840         wdayThis = GetWeekDay();
1841     if ( wdayDst == wdayThis )
1842     {
1843         // nothing to do
1844         return *this;
1845     }
1846
1847     if ( flags == Default_First )
1848     {
1849         flags = GetCountry() == USA ? Sunday_First : Monday_First;
1850     }
1851
1852     // the logic below based on comparing weekday and wdayThis works if Sun (0)
1853     // is the first day in the week, but breaks down for Monday_First case so
1854     // we adjust the week days in this case
1855     if ( flags == Monday_First )
1856     {
1857         if ( wdayThis == Sun )
1858             wdayThis += 7;
1859         if ( wdayDst == Sun )
1860             wdayDst += 7;
1861     }
1862     //else: Sunday_First, nothing to do
1863
1864     // go forward or back in time to the day we want
1865     if ( wdayDst < wdayThis )
1866     {
1867         return Subtract(wxDateSpan::Days(wdayThis - wdayDst));
1868     }
1869     else // weekday > wdayThis
1870     {
1871         return Add(wxDateSpan::Days(wdayDst - wdayThis));
1872     }
1873 }
1874
1875 wxDateTime& wxDateTime::SetToNextWeekDay(WeekDay weekday)
1876 {
1877     wxDATETIME_CHECK( weekday != Inv_WeekDay, _T("invalid weekday") );
1878
1879     int diff;
1880     WeekDay wdayThis = GetWeekDay();
1881     if ( weekday == wdayThis )
1882     {
1883         // nothing to do
1884         return *this;
1885     }
1886     else if ( weekday < wdayThis )
1887     {
1888         // need to advance a week
1889         diff = 7 - (wdayThis - weekday);
1890     }
1891     else // weekday > wdayThis
1892     {
1893         diff = weekday - wdayThis;
1894     }
1895
1896     return Add(wxDateSpan::Days(diff));
1897 }
1898
1899 wxDateTime& wxDateTime::SetToPrevWeekDay(WeekDay weekday)
1900 {
1901     wxDATETIME_CHECK( weekday != Inv_WeekDay, _T("invalid weekday") );
1902
1903     int diff;
1904     WeekDay wdayThis = GetWeekDay();
1905     if ( weekday == wdayThis )
1906     {
1907         // nothing to do
1908         return *this;
1909     }
1910     else if ( weekday > wdayThis )
1911     {
1912         // need to go to previous week
1913         diff = 7 - (weekday - wdayThis);
1914     }
1915     else // weekday < wdayThis
1916     {
1917         diff = wdayThis - weekday;
1918     }
1919
1920     return Subtract(wxDateSpan::Days(diff));
1921 }
1922
1923 bool wxDateTime::SetToWeekDay(WeekDay weekday,
1924                               int n,
1925                               Month month,
1926                               int year)
1927 {
1928     wxCHECK_MSG( weekday != Inv_WeekDay, false, _T("invalid weekday") );
1929
1930     // we don't check explicitly that -5 <= n <= 5 because we will return false
1931     // anyhow in such case - but may be should still give an assert for it?
1932
1933     // take the current month/year if none specified
1934     ReplaceDefaultYearMonthWithCurrent(&year, &month);
1935
1936     wxDateTime dt;
1937
1938     // TODO this probably could be optimised somehow...
1939
1940     if ( n > 0 )
1941     {
1942         // get the first day of the month
1943         dt.Set(1, month, year);
1944
1945         // get its wday
1946         WeekDay wdayFirst = dt.GetWeekDay();
1947
1948         // go to the first weekday of the month
1949         int diff = weekday - wdayFirst;
1950         if ( diff < 0 )
1951             diff += 7;
1952
1953         // add advance n-1 weeks more
1954         diff += 7*(n - 1);
1955
1956         dt += wxDateSpan::Days(diff);
1957     }
1958     else // count from the end of the month
1959     {
1960         // get the last day of the month
1961         dt.SetToLastMonthDay(month, year);
1962
1963         // get its wday
1964         WeekDay wdayLast = dt.GetWeekDay();
1965
1966         // go to the last weekday of the month
1967         int diff = wdayLast - weekday;
1968         if ( diff < 0 )
1969             diff += 7;
1970
1971         // and rewind n-1 weeks from there
1972         diff += 7*(-n - 1);
1973
1974         dt -= wxDateSpan::Days(diff);
1975     }
1976
1977     // check that it is still in the same month
1978     if ( dt.GetMonth() == month )
1979     {
1980         *this = dt;
1981
1982         return true;
1983     }
1984     else
1985     {
1986         // no such day in this month
1987         return false;
1988     }
1989 }
1990
1991 static inline
1992 wxDateTime::wxDateTime_t GetDayOfYearFromTm(const wxDateTime::Tm& tm)
1993 {
1994     return (wxDateTime::wxDateTime_t)(gs_cumulatedDays[wxDateTime::IsLeapYear(tm.year)][tm.mon] + tm.mday);
1995 }
1996
1997 wxDateTime::wxDateTime_t wxDateTime::GetDayOfYear(const TimeZone& tz) const
1998 {
1999     return GetDayOfYearFromTm(GetTm(tz));
2000 }
2001
2002 wxDateTime::wxDateTime_t
2003 wxDateTime::GetWeekOfYear(wxDateTime::WeekFlags flags, const TimeZone& tz) const
2004 {
2005     if ( flags == Default_First )
2006     {
2007         flags = GetCountry() == USA ? Sunday_First : Monday_First;
2008     }
2009
2010     Tm tm(GetTm(tz));
2011     wxDateTime_t nDayInYear = GetDayOfYearFromTm(tm);
2012
2013     int wdTarget = GetWeekDay(tz);
2014     int wdYearStart = wxDateTime(1, Jan, GetYear()).GetWeekDay();
2015     int week;
2016     if ( flags == Sunday_First )
2017     {
2018         // FIXME: First week is not calculated correctly.
2019         week = (nDayInYear - wdTarget + 7) / 7;
2020         if ( wdYearStart == Wed || wdYearStart == Thu )
2021             week++;
2022     }
2023     else // week starts with monday
2024     {
2025         // adjust the weekdays to non-US style.
2026         wdYearStart = ConvertWeekDayToMondayBase(wdYearStart);
2027         wdTarget = ConvertWeekDayToMondayBase(wdTarget);
2028
2029         // quoting from http://www.cl.cam.ac.uk/~mgk25/iso-time.html:
2030         //
2031         //      Week 01 of a year is per definition the first week that has the
2032         //      Thursday in this year, which is equivalent to the week that
2033         //      contains the fourth day of January. In other words, the first
2034         //      week of a new year is the week that has the majority of its
2035         //      days in the new year. Week 01 might also contain days from the
2036         //      previous year and the week before week 01 of a year is the last
2037         //      week (52 or 53) of the previous year even if it contains days
2038         //      from the new year. A week starts with Monday (day 1) and ends
2039         //      with Sunday (day 7).
2040         //
2041
2042         // if Jan 1 is Thursday or less, it is in the first week of this year
2043         if ( wdYearStart < 4 )
2044         {
2045             // count the number of entire weeks between Jan 1 and this date
2046             week = (nDayInYear + wdYearStart + 6 - wdTarget)/7;
2047
2048             // be careful to check for overflow in the next year
2049             if ( week == 53 && tm.mday - wdTarget > 28 )
2050                     week = 1;
2051         }
2052         else // Jan 1 is in the last week of the previous year
2053         {
2054             // check if we happen to be at the last week of previous year:
2055             if ( tm.mon == Jan && tm.mday < 8 - wdYearStart )
2056                 week = wxDateTime(31, Dec, GetYear()-1).GetWeekOfYear();
2057             else
2058                 week = (nDayInYear + wdYearStart - 1 - wdTarget)/7;
2059         }
2060     }
2061
2062     return (wxDateTime::wxDateTime_t)week;
2063 }
2064
2065 wxDateTime::wxDateTime_t wxDateTime::GetWeekOfMonth(wxDateTime::WeekFlags flags,
2066                                                     const TimeZone& tz) const
2067 {
2068     Tm tm = GetTm(tz);
2069     wxDateTime dtMonthStart = wxDateTime(1, tm.mon, tm.year);
2070     int nWeek = GetWeekOfYear(flags) - dtMonthStart.GetWeekOfYear(flags) + 1;
2071     if ( nWeek < 0 )
2072     {
2073         // this may happen for January when Jan, 1 is the last week of the
2074         // previous year
2075         nWeek += IsLeapYear(tm.year - 1) ? 53 : 52;
2076     }
2077
2078     return (wxDateTime::wxDateTime_t)nWeek;
2079 }
2080
2081 wxDateTime& wxDateTime::SetToYearDay(wxDateTime::wxDateTime_t yday)
2082 {
2083     int year = GetYear();
2084     wxDATETIME_CHECK( (0 < yday) && (yday <= GetNumberOfDays(year)),
2085                       _T("invalid year day") );
2086
2087     bool isLeap = IsLeapYear(year);
2088     for ( Month mon = Jan; mon < Inv_Month; wxNextMonth(mon) )
2089     {
2090         // for Dec, we can't compare with gs_cumulatedDays[mon + 1], but we
2091         // don't need it neither - because of the CHECK above we know that
2092         // yday lies in December then
2093         if ( (mon == Dec) || (yday <= gs_cumulatedDays[isLeap][mon + 1]) )
2094         {
2095             Set((wxDateTime::wxDateTime_t)(yday - gs_cumulatedDays[isLeap][mon]), mon, year);
2096
2097             break;
2098         }
2099     }
2100
2101     return *this;
2102 }
2103
2104 // ----------------------------------------------------------------------------
2105 // Julian day number conversion and related stuff
2106 // ----------------------------------------------------------------------------
2107
2108 double wxDateTime::GetJulianDayNumber() const
2109 {
2110     return m_time.ToDouble() / MILLISECONDS_PER_DAY + EPOCH_JDN + 0.5;
2111 }
2112
2113 double wxDateTime::GetRataDie() const
2114 {
2115     // March 1 of the year 0 is Rata Die day -306 and JDN 1721119.5
2116     return GetJulianDayNumber() - 1721119.5 - 306;
2117 }
2118
2119 // ----------------------------------------------------------------------------
2120 // timezone and DST stuff
2121 // ----------------------------------------------------------------------------
2122
2123 int wxDateTime::IsDST(wxDateTime::Country country) const
2124 {
2125     wxCHECK_MSG( country == Country_Default, -1,
2126                  _T("country support not implemented") );
2127
2128     // use the C RTL for the dates in the standard range
2129     time_t timet = GetTicks();
2130     if ( timet != (time_t)-1 )
2131     {
2132         struct tm tmstruct;
2133         tm *tm = wxLocaltime_r(&timet, &tmstruct);
2134
2135         wxCHECK_MSG( tm, -1, _T("wxLocaltime_r() failed") );
2136
2137         return tm->tm_isdst;
2138     }
2139     else
2140     {
2141         int year = GetYear();
2142
2143         if ( !IsDSTApplicable(year, country) )
2144         {
2145             // no DST time in this year in this country
2146             return -1;
2147         }
2148
2149         return IsBetween(GetBeginDST(year, country), GetEndDST(year, country));
2150     }
2151 }
2152
2153 wxDateTime& wxDateTime::MakeTimezone(const TimeZone& tz, bool noDST)
2154 {
2155     long secDiff = GetTimeZone() + tz.GetOffset();
2156
2157     // we need to know whether DST is or not in effect for this date unless
2158     // the test disabled by the caller
2159     if ( !noDST && (IsDST() == 1) )
2160     {
2161         // FIXME we assume that the DST is always shifted by 1 hour
2162         secDiff -= 3600;
2163     }
2164
2165     return Add(wxTimeSpan::Seconds(secDiff));
2166 }
2167
2168 wxDateTime& wxDateTime::MakeFromTimezone(const TimeZone& tz, bool noDST)
2169 {
2170     long secDiff = GetTimeZone() + tz.GetOffset();
2171
2172     // we need to know whether DST is or not in effect for this date unless
2173     // the test disabled by the caller
2174     if ( !noDST && (IsDST() == 1) )
2175     {
2176         // FIXME we assume that the DST is always shifted by 1 hour
2177         secDiff -= 3600;
2178     }
2179
2180     return Subtract(wxTimeSpan::Seconds(secDiff));
2181 }
2182
2183 // ============================================================================
2184 // wxDateTimeHolidayAuthority and related classes
2185 // ============================================================================
2186
2187 #include "wx/arrimpl.cpp"
2188
2189 WX_DEFINE_OBJARRAY(wxDateTimeArray)
2190
2191 static int wxCMPFUNC_CONV
2192 wxDateTimeCompareFunc(wxDateTime **first, wxDateTime **second)
2193 {
2194     wxDateTime dt1 = **first,
2195                dt2 = **second;
2196
2197     return dt1 == dt2 ? 0 : dt1 < dt2 ? -1 : +1;
2198 }
2199
2200 // ----------------------------------------------------------------------------
2201 // wxDateTimeHolidayAuthority
2202 // ----------------------------------------------------------------------------
2203
2204 wxHolidayAuthoritiesArray wxDateTimeHolidayAuthority::ms_authorities;
2205
2206 /* static */
2207 bool wxDateTimeHolidayAuthority::IsHoliday(const wxDateTime& dt)
2208 {
2209     size_t count = ms_authorities.size();
2210     for ( size_t n = 0; n < count; n++ )
2211     {
2212         if ( ms_authorities[n]->DoIsHoliday(dt) )
2213         {
2214             return true;
2215         }
2216     }
2217
2218     return false;
2219 }
2220
2221 /* static */
2222 size_t
2223 wxDateTimeHolidayAuthority::GetHolidaysInRange(const wxDateTime& dtStart,
2224                                                const wxDateTime& dtEnd,
2225                                                wxDateTimeArray& holidays)
2226 {
2227     wxDateTimeArray hol;
2228
2229     holidays.Clear();
2230
2231     const size_t countAuth = ms_authorities.size();
2232     for ( size_t nAuth = 0; nAuth < countAuth; nAuth++ )
2233     {
2234         ms_authorities[nAuth]->DoGetHolidaysInRange(dtStart, dtEnd, hol);
2235
2236         WX_APPEND_ARRAY(holidays, hol);
2237     }
2238
2239     holidays.Sort(wxDateTimeCompareFunc);
2240
2241     return holidays.size();
2242 }
2243
2244 /* static */
2245 void wxDateTimeHolidayAuthority::ClearAllAuthorities()
2246 {
2247     WX_CLEAR_ARRAY(ms_authorities);
2248 }
2249
2250 /* static */
2251 void wxDateTimeHolidayAuthority::AddAuthority(wxDateTimeHolidayAuthority *auth)
2252 {
2253     ms_authorities.push_back(auth);
2254 }
2255
2256 wxDateTimeHolidayAuthority::~wxDateTimeHolidayAuthority()
2257 {
2258     // required here for Darwin
2259 }
2260
2261 // ----------------------------------------------------------------------------
2262 // wxDateTimeWorkDays
2263 // ----------------------------------------------------------------------------
2264
2265 bool wxDateTimeWorkDays::DoIsHoliday(const wxDateTime& dt) const
2266 {
2267     wxDateTime::WeekDay wd = dt.GetWeekDay();
2268
2269     return (wd == wxDateTime::Sun) || (wd == wxDateTime::Sat);
2270 }
2271
2272 size_t wxDateTimeWorkDays::DoGetHolidaysInRange(const wxDateTime& dtStart,
2273                                                 const wxDateTime& dtEnd,
2274                                                 wxDateTimeArray& holidays) const
2275 {
2276     if ( dtStart > dtEnd )
2277     {
2278         wxFAIL_MSG( _T("invalid date range in GetHolidaysInRange") );
2279
2280         return 0u;
2281     }
2282
2283     holidays.Empty();
2284
2285     // instead of checking all days, start with the first Sat after dtStart and
2286     // end with the last Sun before dtEnd
2287     wxDateTime dtSatFirst = dtStart.GetNextWeekDay(wxDateTime::Sat),
2288                dtSatLast = dtEnd.GetPrevWeekDay(wxDateTime::Sat),
2289                dtSunFirst = dtStart.GetNextWeekDay(wxDateTime::Sun),
2290                dtSunLast = dtEnd.GetPrevWeekDay(wxDateTime::Sun),
2291                dt;
2292
2293     for ( dt = dtSatFirst; dt <= dtSatLast; dt += wxDateSpan::Week() )
2294     {
2295         holidays.Add(dt);
2296     }
2297
2298     for ( dt = dtSunFirst; dt <= dtSunLast; dt += wxDateSpan::Week() )
2299     {
2300         holidays.Add(dt);
2301     }
2302
2303     return holidays.GetCount();
2304 }
2305
2306 // ============================================================================
2307 // other helper functions
2308 // ============================================================================
2309
2310 // ----------------------------------------------------------------------------
2311 // iteration helpers: can be used to write a for loop over enum variable like
2312 // this:
2313 //  for ( m = wxDateTime::Jan; m < wxDateTime::Inv_Month; wxNextMonth(m) )
2314 // ----------------------------------------------------------------------------
2315
2316 WXDLLIMPEXP_BASE void wxNextMonth(wxDateTime::Month& m)
2317 {
2318     wxASSERT_MSG( m < wxDateTime::Inv_Month, _T("invalid month") );
2319
2320     // no wrapping or the for loop above would never end!
2321     m = (wxDateTime::Month)(m + 1);
2322 }
2323
2324 WXDLLIMPEXP_BASE void wxPrevMonth(wxDateTime::Month& m)
2325 {
2326     wxASSERT_MSG( m < wxDateTime::Inv_Month, _T("invalid month") );
2327
2328     m = m == wxDateTime::Jan ? wxDateTime::Inv_Month
2329                              : (wxDateTime::Month)(m - 1);
2330 }
2331
2332 WXDLLIMPEXP_BASE void wxNextWDay(wxDateTime::WeekDay& wd)
2333 {
2334     wxASSERT_MSG( wd < wxDateTime::Inv_WeekDay, _T("invalid week day") );
2335
2336     // no wrapping or the for loop above would never end!
2337     wd = (wxDateTime::WeekDay)(wd + 1);
2338 }
2339
2340 WXDLLIMPEXP_BASE void wxPrevWDay(wxDateTime::WeekDay& wd)
2341 {
2342     wxASSERT_MSG( wd < wxDateTime::Inv_WeekDay, _T("invalid week day") );
2343
2344     wd = wd == wxDateTime::Sun ? wxDateTime::Inv_WeekDay
2345                                : (wxDateTime::WeekDay)(wd - 1);
2346 }
2347
2348 #ifdef __WXMSW__
2349
2350 wxDateTime& wxDateTime::SetFromMSWSysTime(const SYSTEMTIME& st)
2351 {
2352     return Set(st.wDay,
2353             static_cast<wxDateTime::Month>(wxDateTime::Jan + st.wMonth - 1),
2354             st.wYear,
2355             0, 0, 0);
2356 }
2357
2358 void wxDateTime::GetAsMSWSysTime(SYSTEMTIME* st) const
2359 {
2360     const wxDateTime::Tm tm(GetTm());
2361
2362     st->wYear = (WXWORD)tm.year;
2363     st->wMonth = (WXWORD)(tm.mon - wxDateTime::Jan + 1);
2364     st->wDay = tm.mday;
2365
2366     st->wDayOfWeek =
2367     st->wHour =
2368     st->wMinute =
2369     st->wSecond =
2370     st->wMilliseconds = 0;
2371 }
2372 #endif // __WXMSW__
2373
2374 #endif // wxUSE_DATETIME