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             struct timeb tb;
 134             ftime(&tb);
 135             return tb.timezone;
 136         }
 137         #define WX_TIMEZONE wxGetTimeZone()
 138     #elif defined(__DARWIN__)
 139         #define WX_GMTOFF_IN_TM
 140     #elif defined(__WXWINCE__) && defined(__VISUALC8__)
 141         // _timezone is not present in dynamic run-time library
 142         #if 0
 143         // Solution (1): use the function equivalent of _timezone
 144         static long wxGetTimeZone()
 145         {
 146             long t;
 147             _get_timezone(& t);
 148             return t;
 149         }
 150         #define WX_TIMEZONE wxGetTimeZone()
 151         #elif 1
 152         // Solution (2): using GetTimeZoneInformation
 153         static long wxGetTimeZone()
 154         {
 155             TIME_ZONE_INFORMATION tzi;
 156             ::GetTimeZoneInformation(&tzi);
 157             return tzi.Bias; // x 60
 158         }
 159         #define WX_TIMEZONE wxGetTimeZone()
 160         #else
 161         // Old method using _timezone: this symbol doesn't exist in the dynamic run-time library (i.e. using /MD)
 162         #define WX_TIMEZONE _timezone
 163         #endif
 164     #else // unknown platform - try timezone
 165         #define WX_TIMEZONE timezone
 166     #endif
 167 #endif // !WX_TIMEZONE && !WX_GMTOFF_IN_TM
 168
 169 // NB: VC8 safe time functions could/should be used for wxMSW as well probably
 170 #if defined(__WXWINCE__) && defined(__VISUALC8__)
 171
 172 struct tm *wxLocaltime_r(const time_t *t, struct tm* tm)
 173 {
 174     __time64_t t64 = *t;
 175     return _localtime64_s(tm, &t64) == 0 ? tm : NULL;
 176 }
 177
 178 struct tm *wxGmtime_r(const time_t* t, struct tm* tm)
 179 {
 180     __time64_t t64 = *t;
 181     return _gmtime64_s(tm, &t64) == 0 ? tm : NULL;
 182 }
 183
 184 #else // !wxWinCE with VC8
 185
 186 #if (!defined(HAVE_LOCALTIME_R) || !defined(HAVE_GMTIME_R)) && wxUSE_THREADS && !defined(__WINDOWS__)
 187 static wxMutex timeLock;
 188 #endif
 189
 190 #ifndef HAVE_LOCALTIME_R
 191 struct tm *wxLocaltime_r(const time_t* ticks, struct tm* temp)
 192 {
 193 #if wxUSE_THREADS && !defined(__WINDOWS__)
 194   // No need to waste time with a mutex on windows since it's using
 195   // thread local storage for localtime anyway.
 196   wxMutexLocker locker(timeLock);
 197 #endif
 198
 199   // Borland CRT crashes when passed 0 ticks for some reason, see SF bug 1704438
 200 #ifdef __BORLANDC__
 201   if ( !*ticks )
 202       return NULL;
 203 #endif
 204
 205   const tm * const t = localtime(ticks);
 206   if ( !t )
 207       return NULL;
 208
 209   memcpy(temp, t, sizeof(struct tm));
 210   return temp;
 211 }
 212 #endif // !HAVE_LOCALTIME_R
 213
 214 #ifndef HAVE_GMTIME_R
 215 struct tm *wxGmtime_r(const time_t* ticks, struct tm* temp)
 216 {
 217 #if wxUSE_THREADS && !defined(__WINDOWS__)
 218   // No need to waste time with a mutex on windows since it's
 219   // using thread local storage for gmtime anyway.
 220   wxMutexLocker locker(timeLock);
 221 #endif
 222
 223 #ifdef __BORLANDC__
 224   if ( !*ticks )
 225       return NULL;
 226 #endif
 227
 228   const tm * const t = gmtime(ticks);
 229   if ( !t )
 230       return NULL;
 231
 232   memcpy(temp, gmtime(ticks), sizeof(struct tm));
 233   return temp;
 234 }
 235 #endif // !HAVE_GMTIME_R
 236
 237 #endif // wxWinCE with VC8/other platforms
 238
 239 // ----------------------------------------------------------------------------
 240 // macros
 241 // ----------------------------------------------------------------------------
 242
 243 // debugging helper: just a convenient replacement of wxCHECK()
 244 #define wxDATETIME_CHECK(expr, msg) \
 245     wxCHECK2_MSG(expr, *this = wxInvalidDateTime; return *this, msg)
 246
 247 // ----------------------------------------------------------------------------
 248 // private classes
 249 // ----------------------------------------------------------------------------
 250
 251 class wxDateTimeHolidaysModule : public wxModule
 252 {
 253 public:
 254     virtual bool OnInit()
 255     {
 256         wxDateTimeHolidayAuthority::AddAuthority(new wxDateTimeWorkDays);
 257
 258         return true;
 259     }
 260
 261     virtual void OnExit()
 262     {
 263         wxDateTimeHolidayAuthority::ClearAllAuthorities();
 264         wxDateTimeHolidayAuthority::ms_authorities.clear();
 265     }
 266
 267 private:
 268     DECLARE_DYNAMIC_CLASS(wxDateTimeHolidaysModule)
 269 };
 270
 271 IMPLEMENT_DYNAMIC_CLASS(wxDateTimeHolidaysModule, wxModule)
 272
 273 // ----------------------------------------------------------------------------
 274 // constants
 275 // ----------------------------------------------------------------------------
 276
 277 // some trivial ones
 278 static const int MONTHS_IN_YEAR = 12;
 279
 280 static const int SEC_PER_MIN = 60;
 281
 282 static const int MIN_PER_HOUR = 60;
 283
 284 static const long SECONDS_PER_DAY = 86400l;
 285
 286 static const int DAYS_PER_WEEK = 7;
 287
 288 static const long MILLISECONDS_PER_DAY = 86400000l;
 289
 290 // this is the integral part of JDN of the midnight of Jan 1, 1970
 291 // (i.e. JDN(Jan 1, 1970) = 2440587.5)
 292 static const long EPOCH_JDN = 2440587l;
 293
 294 // these values are only used in asserts so don't define them if asserts are
 295 // disabled to avoid warnings about unused static variables
 296 #if wxDEBUG_LEVEL
 297 // the date of JDN -0.5 (as we don't work with fractional parts, this is the
 298 // reference date for us) is Nov 24, 4714BC
 299 static const int JDN_0_YEAR = -4713;
 300 static const int JDN_0_MONTH = wxDateTime::Nov;
 301 static const int JDN_0_DAY = 24;
 302 #endif // wxDEBUG_LEVEL
 303
 304 // the constants used for JDN calculations
 305 static const long JDN_OFFSET         = 32046l;
 306 static const long DAYS_PER_5_MONTHS  = 153l;
 307 static const long DAYS_PER_4_YEARS   = 1461l;
 308 static const long DAYS_PER_400_YEARS = 146097l;
 309
 310 // this array contains the cumulated number of days in all previous months for
 311 // normal and leap years
 312 static const wxDateTime::wxDateTime_t gs_cumulatedDays[2][MONTHS_IN_YEAR] =
 313 {
 314     { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 },
 315     { 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335 }
 316 };
 317
 318 const long wxDateTime::TIME_T_FACTOR = 1000l;
 319
 320 // ----------------------------------------------------------------------------
 321 // global data
 322 // ----------------------------------------------------------------------------
 323
 324 const char wxDefaultDateTimeFormat[] = "%c";
 325 const char wxDefaultTimeSpanFormat[] = "%H:%M:%S";
 326
 327 // in the fine tradition of ANSI C we use our equivalent of (time_t)-1 to
 328 // indicate an invalid wxDateTime object
 329 const wxDateTime wxDefaultDateTime;
 330
 331 wxDateTime::Country wxDateTime::ms_country = wxDateTime::Country_Unknown;
 332
 333 // ----------------------------------------------------------------------------
 334 // private functions
 335 // ----------------------------------------------------------------------------
 336
 337 // debugger helper: this function can be called from a debugger to show what
 338 // the date really is
 339 extern const char *wxDumpDate(const wxDateTime* dt)
 340 {
 341     static char buf[128];
 342
 343     wxString fmt(dt->Format("%Y-%m-%d (%a) %H:%M:%S"));
 344     wxStrlcpy(buf,
 345               (fmt + " (" + dt->GetValue().ToString() + " ticks)").ToAscii(),
 346               WXSIZEOF(buf));
 347
 348     return buf;
 349 }
 350
 351 // get the number of days in the given month of the given year
 352 static inline
 353 wxDateTime::wxDateTime_t GetNumOfDaysInMonth(int year, wxDateTime::Month month)
 354 {
 355     // the number of days in month in Julian/Gregorian calendar: the first line
 356     // is for normal years, the second one is for the leap ones
 357     static const wxDateTime::wxDateTime_t daysInMonth[2][MONTHS_IN_YEAR] =
 358     {
 359         { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
 360         { 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
 361     };
 362
 363     return daysInMonth[wxDateTime::IsLeapYear(year)][month];
 364 }
 365
 366 // returns the time zone in the C sense, i.e. the difference UTC - local
 367 // (in seconds)
 368 // NOTE: not static because used by datetimefmt.cpp
 369 int GetTimeZone()
 370 {
 371 #ifdef WX_GMTOFF_IN_TM
 372     // set to true when the timezone is set
 373     static bool s_timezoneSet = false;
 374     static long gmtoffset = LONG_MAX; // invalid timezone
 375
 376     // ensure that the timezone variable is set by calling wxLocaltime_r
 377     if ( !s_timezoneSet )
 378     {
 379         // just call wxLocaltime_r() instead of figuring out whether this
 380         // system supports tzset(), _tzset() or something else
 381         time_t t = 0;
 382         struct tm tm;
 383
 384         wxLocaltime_r(&t, &tm);
 385         s_timezoneSet = true;
 386
 387         // note that GMT offset is the opposite of time zone and so to return
 388         // consistent results in both WX_GMTOFF_IN_TM and !WX_GMTOFF_IN_TM
 389         // cases we have to negate it
 390         gmtoffset = -tm.tm_gmtoff;
 391     }
 392     return (int)gmtoffset;
 393 #else // !WX_GMTOFF_IN_TM
 394     return WX_TIMEZONE;
 395 #endif // WX_GMTOFF_IN_TM/!WX_GMTOFF_IN_TM
 396 }
 397
 398 // return the integral part of the JDN for the midnight of the given date (to
 399 // get the real JDN you need to add 0.5, this is, in fact, JDN of the
 400 // noon of the previous day)
 401 static long GetTruncatedJDN(wxDateTime::wxDateTime_t day,
 402                             wxDateTime::Month mon,
 403                             int year)
 404 {
 405     // CREDIT: code below is by Scott E. Lee (but bugs are mine)
 406
 407     // check the date validity
 408     wxASSERT_MSG(
 409       (year > JDN_0_YEAR) ||
 410       ((year == JDN_0_YEAR) && (mon > JDN_0_MONTH)) ||
 411       ((year == JDN_0_YEAR) && (mon == JDN_0_MONTH) && (day >= JDN_0_DAY)),
 412       wxT("date out of range - can't convert to JDN")
 413                 );
 414
 415     // make the year positive to avoid problems with negative numbers division
 416     year += 4800;
 417
 418     // months are counted from March here
 419     int month;
 420     if ( mon >= wxDateTime::Mar )
 421     {
 422         month = mon - 2;
 423     }
 424     else
 425     {
 426         month = mon + 10;
 427         year--;
 428     }
 429
 430     // now we can simply add all the contributions together
 431     return ((year / 100) * DAYS_PER_400_YEARS) / 4
 432             + ((year % 100) * DAYS_PER_4_YEARS) / 4
 433             + (month * DAYS_PER_5_MONTHS + 2) / 5
 434             + day
 435             - JDN_OFFSET;
 436 }
 437
 438 #ifdef wxHAS_STRFTIME
 439
 440 // this function is a wrapper around strftime(3) adding error checking
 441 // NOTE: not static because used by datetimefmt.cpp
 442 wxString CallStrftime(const wxString& format, const tm* tm)
 443 {
 444     wxChar buf[4096];
 445     // Create temp wxString here to work around mingw/cygwin bug 1046059
 446     // http://sourceforge.net/tracker/?func=detail&atid=102435&aid=1046059&group_id=2435
 447     wxString s;
 448
 449     if ( !wxStrftime(buf, WXSIZEOF(buf), format, tm) )
 450     {
 451         // if the format is valid, buffer must be too small?
 452         wxFAIL_MSG(wxT("strftime() failed"));
 453
 454         buf[0] = '\0';
 455     }
 456
 457     s = buf;
 458     return s;
 459 }
 460
 461 #endif // wxHAS_STRFTIME
 462
 463 // if year and/or month have invalid values, replace them with the current ones
 464 static void ReplaceDefaultYearMonthWithCurrent(int *year,
 465                                                wxDateTime::Month *month)
 466 {
 467     struct tm *tmNow = NULL;
 468     struct tm tmstruct;
 469
 470     if ( *year == wxDateTime::Inv_Year )
 471     {
 472         tmNow = wxDateTime::GetTmNow(&tmstruct);
 473
 474         *year = 1900 + tmNow->tm_year;
 475     }
 476
 477     if ( *month == wxDateTime::Inv_Month )
 478     {
 479         if ( !tmNow )
 480             tmNow = wxDateTime::GetTmNow(&tmstruct);
 481
 482         *month = (wxDateTime::Month)tmNow->tm_mon;
 483     }
 484 }
 485
 486 // fill the struct tm with default values
 487 // NOTE: not static because used by datetimefmt.cpp
 488 void InitTm(struct tm& tm)
 489 {
 490     // struct tm may have etxra fields (undocumented and with unportable
 491     // names) which, nevertheless, must be set to 0
 492     memset(&tm, 0, sizeof(struct tm));
 493
 494     tm.tm_mday = 1;   // mday 0 is invalid
 495     tm.tm_year = 76;  // any valid year
 496     tm.tm_isdst = -1; // auto determine
 497 }
 498
 499 // ============================================================================
 500 // implementation of wxDateTime
 501 // ============================================================================
 502
 503 // ----------------------------------------------------------------------------
 504 // struct Tm
 505 // ----------------------------------------------------------------------------
 506
 507 wxDateTime::Tm::Tm()
 508 {
 509     year = (wxDateTime_t)wxDateTime::Inv_Year;
 510     mon = wxDateTime::Inv_Month;
 511     mday =
 512     yday = 0;
 513     hour =
 514     min =
 515     sec =
 516     msec = 0;
 517     wday = wxDateTime::Inv_WeekDay;
 518 }
 519
 520 wxDateTime::Tm::Tm(const struct tm& tm, const TimeZone& tz)
 521               : m_tz(tz)
 522 {
 523     msec = 0;
 524     sec = (wxDateTime::wxDateTime_t)tm.tm_sec;
 525     min = (wxDateTime::wxDateTime_t)tm.tm_min;
 526     hour = (wxDateTime::wxDateTime_t)tm.tm_hour;
 527     mday = (wxDateTime::wxDateTime_t)tm.tm_mday;
 528     mon = (wxDateTime::Month)tm.tm_mon;
 529     year = 1900 + tm.tm_year;
 530     wday = (wxDateTime::wxDateTime_t)tm.tm_wday;
 531     yday = (wxDateTime::wxDateTime_t)tm.tm_yday;
 532 }
 533
 534 bool wxDateTime::Tm::IsValid() const
 535 {
 536     // we allow for the leap seconds, although we don't use them (yet)
 537     return (year != wxDateTime::Inv_Year) && (mon != wxDateTime::Inv_Month) &&
 538            (mday <= GetNumOfDaysInMonth(year, mon)) &&
 539            (hour < 24) && (min < 60) && (sec < 62) && (msec < 1000);
 540 }
 541
 542 void wxDateTime::Tm::ComputeWeekDay()
 543 {
 544     // compute the week day from day/month/year: we use the dumbest algorithm
 545     // possible: just compute our JDN and then use the (simple to derive)
 546     // formula: weekday = (JDN + 1.5) % 7
 547     wday = (wxDateTime::wxDateTime_t)((GetTruncatedJDN(mday, mon, year) + 2) % 7);
 548 }
 549
 550 void wxDateTime::Tm::AddMonths(int monDiff)
 551 {
 552     // normalize the months field
 553     while ( monDiff < -mon )
 554     {
 555         year--;
 556
 557         monDiff += MONTHS_IN_YEAR;
 558     }
 559
 560     while ( monDiff + mon >= MONTHS_IN_YEAR )
 561     {
 562         year++;
 563
 564         monDiff -= MONTHS_IN_YEAR;
 565     }
 566
 567     mon = (wxDateTime::Month)(mon + monDiff);
 568
 569     wxASSERT_MSG( mon >= 0 && mon < MONTHS_IN_YEAR, wxT("logic error") );
 570
 571     // NB: we don't check here that the resulting date is valid, this function
 572     //     is private and the caller must check it if needed
 573 }
 574
 575 void wxDateTime::Tm::AddDays(int dayDiff)
 576 {
 577     // normalize the days field
 578     while ( dayDiff + mday < 1 )
 579     {
 580         AddMonths(-1);
 581
 582         dayDiff += GetNumOfDaysInMonth(year, mon);
 583     }
 584
 585     mday = (wxDateTime::wxDateTime_t)( mday + dayDiff );
 586     while ( mday > GetNumOfDaysInMonth(year, mon) )
 587     {
 588         mday -= GetNumOfDaysInMonth(year, mon);
 589
 590         AddMonths(1);
 591     }
 592
 593     wxASSERT_MSG( mday > 0 && mday <= GetNumOfDaysInMonth(year, mon),
 594                   wxT("logic error") );
 595 }
 596
 597 // ----------------------------------------------------------------------------
 598 // class TimeZone
 599 // ----------------------------------------------------------------------------
 600
 601 wxDateTime::TimeZone::TimeZone(wxDateTime::TZ tz)
 602 {
 603     switch ( tz )
 604     {
 605         case wxDateTime::Local:
 606             // get the offset from C RTL: it returns the difference GMT-local
 607             // while we want to have the offset _from_ GMT, hence the '-'
 608             m_offset = -GetTimeZone();
 609             break;
 610
 611         case wxDateTime::GMT_12:
 612         case wxDateTime::GMT_11:
 613         case wxDateTime::GMT_10:
 614         case wxDateTime::GMT_9:
 615         case wxDateTime::GMT_8:
 616         case wxDateTime::GMT_7:
 617         case wxDateTime::GMT_6:
 618         case wxDateTime::GMT_5:
 619         case wxDateTime::GMT_4:
 620         case wxDateTime::GMT_3:
 621         case wxDateTime::GMT_2:
 622         case wxDateTime::GMT_1:
 623             m_offset = -3600*(wxDateTime::GMT0 - tz);
 624             break;
 625
 626         case wxDateTime::GMT0:
 627         case wxDateTime::GMT1:
 628         case wxDateTime::GMT2:
 629         case wxDateTime::GMT3:
 630         case wxDateTime::GMT4:
 631         case wxDateTime::GMT5:
 632         case wxDateTime::GMT6:
 633         case wxDateTime::GMT7:
 634         case wxDateTime::GMT8:
 635         case wxDateTime::GMT9:
 636         case wxDateTime::GMT10:
 637         case wxDateTime::GMT11:
 638         case wxDateTime::GMT12:
 639         case wxDateTime::GMT13:
 640             m_offset = 3600*(tz - wxDateTime::GMT0);
 641             break;
 642
 643         case wxDateTime::A_CST:
 644             // Central Standard Time in use in Australia = UTC + 9.5
 645             m_offset = 60l*(9*MIN_PER_HOUR + MIN_PER_HOUR/2);
 646             break;
 647
 648         default:
 649             wxFAIL_MSG( wxT("unknown time zone") );
 650     }
 651 }
 652
 653 // ----------------------------------------------------------------------------
 654 // static functions
 655 // ----------------------------------------------------------------------------
 656
 657 /* static */
 658 struct tm *wxDateTime::GetTmNow(struct tm *tmstruct)
 659 {
 660     time_t t = GetTimeNow();
 661     return wxLocaltime_r(&t, tmstruct);
 662 }
 663
 664 /* static */
 665 bool wxDateTime::IsLeapYear(int year, wxDateTime::Calendar cal)
 666 {
 667     if ( year == Inv_Year )
 668         year = GetCurrentYear();
 669
 670     if ( cal == Gregorian )
 671     {
 672         // in Gregorian calendar leap years are those divisible by 4 except
 673         // those divisible by 100 unless they're also divisible by 400
 674         // (in some countries, like Russia and Greece, additional corrections
 675         // exist, but they won't manifest themselves until 2700)
 676         return (year % 4 == 0) && ((year % 100 != 0) || (year % 400 == 0));
 677     }
 678     else if ( cal == Julian )
 679     {
 680         // in Julian calendar the rule is simpler
 681         return year % 4 == 0;
 682     }
 683     else
 684     {
 685         wxFAIL_MSG(wxT("unknown calendar"));
 686
 687         return false;
 688     }
 689 }
 690
 691 /* static */
 692 int wxDateTime::GetCentury(int year)
 693 {
 694     return year > 0 ? year / 100 : year / 100 - 1;
 695 }
 696
 697 /* static */
 698 int wxDateTime::ConvertYearToBC(int year)
 699 {
 700     // year 0 is BC 1
 701     return year > 0 ? year : year - 1;
 702 }
 703
 704 /* static */
 705 int wxDateTime::GetCurrentYear(wxDateTime::Calendar cal)
 706 {
 707     switch ( cal )
 708     {
 709         case Gregorian:
 710             return Now().GetYear();
 711
 712         case Julian:
 713             wxFAIL_MSG(wxT("TODO"));
 714             break;
 715
 716         default:
 717             wxFAIL_MSG(wxT("unsupported calendar"));
 718             break;
 719     }
 720
 721     return Inv_Year;
 722 }
 723
 724 /* static */
 725 wxDateTime::Month wxDateTime::GetCurrentMonth(wxDateTime::Calendar cal)
 726 {
 727     switch ( cal )
 728     {
 729         case Gregorian:
 730             return Now().GetMonth();
 731
 732         case Julian:
 733             wxFAIL_MSG(wxT("TODO"));
 734             break;
 735
 736         default:
 737             wxFAIL_MSG(wxT("unsupported calendar"));
 738             break;
 739     }
 740
 741     return Inv_Month;
 742 }
 743
 744 /* static */
 745 wxDateTime::wxDateTime_t wxDateTime::GetNumberOfDays(int year, Calendar cal)
 746 {
 747     if ( year == Inv_Year )
 748     {
 749         // take the current year if none given
 750         year = GetCurrentYear();
 751     }
 752
 753     switch ( cal )
 754     {
 755         case Gregorian:
 756         case Julian:
 757             return IsLeapYear(year) ? 366 : 365;
 758
 759         default:
 760             wxFAIL_MSG(wxT("unsupported calendar"));
 761             break;
 762     }
 763
 764     return 0;
 765 }
 766
 767 /* static */
 768 wxDateTime::wxDateTime_t wxDateTime::GetNumberOfDays(wxDateTime::Month month,
 769                                                      int year,
 770                                                      wxDateTime::Calendar cal)
 771 {
 772     wxCHECK_MSG( month < MONTHS_IN_YEAR, 0, wxT("invalid month") );
 773
 774     if ( cal == Gregorian || cal == Julian )
 775     {
 776         if ( year == Inv_Year )
 777         {
 778             // take the current year if none given
 779             year = GetCurrentYear();
 780         }
 781
 782         return GetNumOfDaysInMonth(year, month);
 783     }
 784     else
 785     {
 786         wxFAIL_MSG(wxT("unsupported calendar"));
 787
 788         return 0;
 789     }
 790 }
 791
 792 namespace
 793 {
 794
 795 // helper function used by GetEnglish/WeekDayName(): returns 0 if flags is
 796 // Name_Full and 1 if it is Name_Abbr or -1 if the flags is incorrect (and
 797 // asserts in this case)
 798 //
 799 // the return value of this function is used as an index into 2D array
 800 // containing full names in its first row and abbreviated ones in the 2nd one
 801 int NameArrayIndexFromFlag(wxDateTime::NameFlags flags)
 802 {
 803     switch ( flags )
 804     {
 805         case wxDateTime::Name_Full:
 806             return 0;
 807
 808         case wxDateTime::Name_Abbr:
 809             return 1;
 810
 811         default:
 812             wxFAIL_MSG( "unknown wxDateTime::NameFlags value" );
 813     }
 814
 815     return -1;
 816 }
 817
 818 } // anonymous namespace
 819
 820 /* static */
 821 wxString wxDateTime::GetEnglishMonthName(Month month, NameFlags flags)
 822 {
 823     wxCHECK_MSG( month != Inv_Month, wxEmptyString, "invalid month" );
 824
 825     static const char *const monthNames[2][MONTHS_IN_YEAR] =
 826     {
 827         { "January", "February", "March", "April", "May", "June",
 828           "July", "August", "September", "October", "November", "December" },
 829         { "Jan", "Feb", "Mar", "Apr", "May", "Jun",
 830           "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" }
 831     };
 832
 833     const int idx = NameArrayIndexFromFlag(flags);
 834     if ( idx == -1 )
 835         return wxString();
 836
 837     return monthNames[idx][month];
 838 }
 839
 840 /* static */
 841 wxString wxDateTime::GetMonthName(wxDateTime::Month month,
 842                                   wxDateTime::NameFlags flags)
 843 {
 844 #ifdef wxHAS_STRFTIME
 845     wxCHECK_MSG( month != Inv_Month, wxEmptyString, wxT("invalid month") );
 846
 847     // notice that we must set all the fields to avoid confusing libc (GNU one
 848     // gets confused to a crash if we don't do this)
 849     tm tm;
 850     InitTm(tm);
 851     tm.tm_mon = month;
 852
 853     return CallStrftime(flags == Name_Abbr ? wxT("%b") : wxT("%B"), &tm);
 854 #else // !wxHAS_STRFTIME
 855     return GetEnglishMonthName(month, flags);
 856 #endif // wxHAS_STRFTIME/!wxHAS_STRFTIME
 857 }
 858
 859 /* static */
 860 wxString wxDateTime::GetEnglishWeekDayName(WeekDay wday, NameFlags flags)
 861 {
 862     wxCHECK_MSG( wday != Inv_WeekDay, wxEmptyString, wxT("invalid weekday") );
 863
 864     static const char *const weekdayNames[2][DAYS_PER_WEEK] =
 865     {
 866         { "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday",
 867           "Saturday" },
 868         { "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat" },
 869     };
 870
 871     const int idx = NameArrayIndexFromFlag(flags);
 872     if ( idx == -1 )
 873         return wxString();
 874
 875     return weekdayNames[idx][wday];
 876 }
 877
 878 /* static */
 879 wxString wxDateTime::GetWeekDayName(wxDateTime::WeekDay wday,
 880                                     wxDateTime::NameFlags flags)
 881 {
 882 #ifdef wxHAS_STRFTIME
 883     wxCHECK_MSG( wday != Inv_WeekDay, wxEmptyString, wxT("invalid weekday") );
 884
 885     // take some arbitrary Sunday (but notice that the day should be such that
 886     // after adding wday to it below we still have a valid date, e.g. don't
 887     // take 28 here!)
 888     tm tm;
 889     InitTm(tm);
 890     tm.tm_mday = 21;
 891     tm.tm_mon = Nov;
 892     tm.tm_year = 99;
 893
 894     // and offset it by the number of days needed to get the correct wday
 895     tm.tm_mday += wday;
 896
 897     // call mktime() to normalize it...
 898     (void)mktime(&tm);
 899
 900     // ... and call strftime()
 901     return CallStrftime(flags == Name_Abbr ? wxT("%a") : wxT("%A"), &tm);
 902 #else // !wxHAS_STRFTIME
 903     return GetEnglishWeekDayName(wday, flags);
 904 #endif // wxHAS_STRFTIME/!wxHAS_STRFTIME
 905 }
 906
 907 /* static */
 908 void wxDateTime::GetAmPmStrings(wxString *am, wxString *pm)
 909 {
 910     tm tm;
 911     InitTm(tm);
 912     wxChar buffer[64];
 913     // @Note: Do not call 'CallStrftime' here! CallStrftime checks the return code
 914     // and causes an assertion failed if the buffer is to small (which is good) - OR -
 915     // if strftime does not return anything because the format string is invalid - OR -
 916     // if there are no 'am' / 'pm' tokens defined for the current locale (which is not good).
 917     // wxDateTime::ParseTime will try several different formats to parse the time.
 918     // As a result, GetAmPmStrings might get called, even if the current locale
 919     // does not define any 'am' / 'pm' tokens. In this case, wxStrftime would
 920     // assert, even though it is a perfectly legal use.
 921     if ( am )
 922     {
 923         if (wxStrftime(buffer, WXSIZEOF(buffer), wxT("%p"), &tm) > 0)
 924             *am = wxString(buffer);
 925         else
 926             *am = wxString();
 927     }
 928     if ( pm )
 929     {
 930         tm.tm_hour = 13;
 931         if (wxStrftime(buffer, WXSIZEOF(buffer), wxT("%p"), &tm) > 0)
 932             *pm = wxString(buffer);
 933         else
 934             *pm = wxString();
 935     }
 936 }
 937
 938
 939 // ----------------------------------------------------------------------------
 940 // Country stuff: date calculations depend on the country (DST, work days,
 941 // ...), so we need to know which rules to follow.
 942 // ----------------------------------------------------------------------------
 943
 944 /* static */
 945 wxDateTime::Country wxDateTime::GetCountry()
 946 {
 947     // TODO use LOCALE_ICOUNTRY setting under Win32
 948 #ifndef __WXWINCE__
 949     if ( ms_country == Country_Unknown )
 950     {
 951         // try to guess from the time zone name
 952         time_t t = time(NULL);
 953         struct tm tmstruct;
 954         struct tm *tm = wxLocaltime_r(&t, &tmstruct);
 955
 956         wxString tz = CallStrftime(wxT("%Z"), tm);
 957         if ( tz == wxT("WET") || tz == wxT("WEST") )
 958         {
 959             ms_country = UK;
 960         }
 961         else if ( tz == wxT("CET") || tz == wxT("CEST") )
 962         {
 963             ms_country = Country_EEC;
 964         }
 965         else if ( tz == wxT("MSK") || tz == wxT("MSD") )
 966         {
 967             ms_country = Russia;
 968         }
 969         else if ( tz == wxT("AST") || tz == wxT("ADT") ||
 970                   tz == wxT("EST") || tz == wxT("EDT") ||
 971                   tz == wxT("CST") || tz == wxT("CDT") ||
 972                   tz == wxT("MST") || tz == wxT("MDT") ||
 973                   tz == wxT("PST") || tz == wxT("PDT") )
 974         {
 975             ms_country = USA;
 976         }
 977         else
 978         {
 979             // well, choose a default one
 980             ms_country = USA;
 981         }
 982     }
 983 #else // __WXWINCE__
 984      ms_country = USA;
 985 #endif // !__WXWINCE__/__WXWINCE__
 986
 987     return ms_country;
 988 }
 989
 990 /* static */
 991 void wxDateTime::SetCountry(wxDateTime::Country country)
 992 {
 993     ms_country = country;
 994 }
 995
 996 /* static */
 997 bool wxDateTime::IsWestEuropeanCountry(Country country)
 998 {
 999     if ( country == Country_Default )
1000     {
1001         country = GetCountry();
1002     }
1003
1004     return (Country_WesternEurope_Start <= country) &&
1005            (country <= Country_WesternEurope_End);
1006 }
1007
1008 // ----------------------------------------------------------------------------
1009 // DST calculations: we use 3 different rules for the West European countries,
1010 // USA and for the rest of the world. This is undoubtedly false for many
1011 // countries, but I lack the necessary info (and the time to gather it),
1012 // please add the other rules here!
1013 // ----------------------------------------------------------------------------
1014
1015 /* static */
1016 bool wxDateTime::IsDSTApplicable(int year, Country country)
1017 {
1018     if ( year == Inv_Year )
1019     {
1020         // take the current year if none given
1021         year = GetCurrentYear();
1022     }
1023
1024     if ( country == Country_Default )
1025     {
1026         country = GetCountry();
1027     }
1028
1029     switch ( country )
1030     {
1031         case USA:
1032         case UK:
1033             // DST was first observed in the US and UK during WWI, reused
1034             // during WWII and used again since 1966
1035             return year >= 1966 ||
1036                    (year >= 1942 && year <= 1945) ||
1037                    (year == 1918 || year == 1919);
1038
1039         default:
1040             // assume that it started after WWII
1041             return year > 1950;
1042     }
1043 }
1044
1045 /* static */
1046 wxDateTime wxDateTime::GetBeginDST(int year, Country country)
1047 {
1048     if ( year == Inv_Year )
1049     {
1050         // take the current year if none given
1051         year = GetCurrentYear();
1052     }
1053
1054     if ( country == Country_Default )
1055     {
1056         country = GetCountry();
1057     }
1058
1059     if ( !IsDSTApplicable(year, country) )
1060     {
1061         return wxInvalidDateTime;
1062     }
1063
1064     wxDateTime dt;
1065
1066     if ( IsWestEuropeanCountry(country) || (country == Russia) )
1067     {
1068         // DST begins at 1 a.m. GMT on the last Sunday of March
1069         if ( !dt.SetToLastWeekDay(Sun, Mar, year) )
1070         {
1071             // weird...
1072             wxFAIL_MSG( wxT("no last Sunday in March?") );
1073         }
1074
1075         dt += wxTimeSpan::Hours(1);
1076     }
1077     else switch ( country )
1078     {
1079         case USA:
1080             switch ( year )
1081             {
1082                 case 1918:
1083                 case 1919:
1084                     // don't know for sure - assume it was in effect all year
1085
1086                 case 1943:
1087                 case 1944:
1088                 case 1945:
1089                     dt.Set(1, Jan, year);
1090                     break;
1091
1092                 case 1942:
1093                     // DST was installed Feb 2, 1942 by the Congress
1094                     dt.Set(2, Feb, year);
1095                     break;
1096
1097                     // Oil embargo changed the DST period in the US
1098                 case 1974:
1099                     dt.Set(6, Jan, 1974);
1100                     break;
1101
1102                 case 1975:
1103                     dt.Set(23, Feb, 1975);
1104                     break;
1105
1106                 default:
1107                     // before 1986, DST begun on the last Sunday of April, but
1108                     // in 1986 Reagan changed it to begin at 2 a.m. of the
1109                     // first Sunday in April
1110                     if ( year < 1986 )
1111                     {
1112                         if ( !dt.SetToLastWeekDay(Sun, Apr, year) )
1113                         {
1114                             // weird...
1115                             wxFAIL_MSG( wxT("no first Sunday in April?") );
1116                         }
1117                     }
1118                     else if ( year > 2006 )
1119                     // Energy Policy Act of 2005, Pub. L. no. 109-58, 119 Stat 594 (2005).
1120                     // Starting in 2007, daylight time begins in the United States on the
1121                     // second Sunday in March and ends on the first Sunday in November
1122                     {
1123                         if ( !dt.SetToWeekDay(Sun, 2, Mar, year) )
1124                         {
1125                             // weird...
1126                             wxFAIL_MSG( wxT("no second Sunday in March?") );
1127                         }
1128                     }
1129                     else
1130                     {
1131                         if ( !dt.SetToWeekDay(Sun, 1, Apr, year) )
1132                         {
1133                             // weird...
1134                             wxFAIL_MSG( wxT("no first Sunday in April?") );
1135                         }
1136                     }
1137
1138                     dt += wxTimeSpan::Hours(2);
1139
1140                     // TODO what about timezone??
1141             }
1142
1143             break;
1144
1145         default:
1146             // assume Mar 30 as the start of the DST for the rest of the world
1147             // - totally bogus, of course
1148             dt.Set(30, Mar, year);
1149     }
1150
1151     return dt;
1152 }
1153
1154 /* static */
1155 wxDateTime wxDateTime::GetEndDST(int year, Country country)
1156 {
1157     if ( year == Inv_Year )
1158     {
1159         // take the current year if none given
1160         year = GetCurrentYear();
1161     }
1162
1163     if ( country == Country_Default )
1164     {
1165         country = GetCountry();
1166     }
1167
1168     if ( !IsDSTApplicable(year, country) )
1169     {
1170         return wxInvalidDateTime;
1171     }
1172
1173     wxDateTime dt;
1174
1175     if ( IsWestEuropeanCountry(country) || (country == Russia) )
1176     {
1177         // DST ends at 1 a.m. GMT on the last Sunday of October
1178         if ( !dt.SetToLastWeekDay(Sun, Oct, year) )
1179         {
1180             // weirder and weirder...
1181             wxFAIL_MSG( wxT("no last Sunday in October?") );
1182         }
1183
1184         dt += wxTimeSpan::Hours(1);
1185     }
1186     else switch ( country )
1187     {
1188         case USA:
1189             switch ( year )
1190             {
1191                 case 1918:
1192                 case 1919:
1193                     // don't know for sure - assume it was in effect all year
1194
1195                 case 1943:
1196                 case 1944:
1197                     dt.Set(31, Dec, year);
1198                     break;
1199
1200                 case 1945:
1201                     // the time was reset after the end of the WWII
1202                     dt.Set(30, Sep, year);
1203                     break;
1204
1205                 default: // default for switch (year)
1206                     if ( year > 2006 )
1207                       // Energy Policy Act of 2005, Pub. L. no. 109-58, 119 Stat 594 (2005).
1208                       // Starting in 2007, daylight time begins in the United States on the
1209                       // second Sunday in March and ends on the first Sunday in November
1210                     {
1211                         if ( !dt.SetToWeekDay(Sun, 1, Nov, year) )
1212                         {
1213                             // weird...
1214                             wxFAIL_MSG( wxT("no first Sunday in November?") );
1215                         }
1216                     }
1217                     else
1218                      // pre-2007
1219                      // DST ends at 2 a.m. on the last Sunday of October
1220                     {
1221                         if ( !dt.SetToLastWeekDay(Sun, Oct, year) )
1222                         {
1223                             // weirder and weirder...
1224                             wxFAIL_MSG( wxT("no last Sunday in October?") );
1225                         }
1226                     }
1227
1228                     dt += wxTimeSpan::Hours(2);
1229
1230             // TODO: what about timezone??
1231             }
1232             break;
1233
1234         default: // default for switch (country)
1235             // assume October 26th as the end of the DST - totally bogus too
1236             dt.Set(26, Oct, year);
1237     }
1238
1239     return dt;
1240 }
1241
1242 // ----------------------------------------------------------------------------
1243 // constructors and assignment operators
1244 // ----------------------------------------------------------------------------
1245
1246 // return the current time with ms precision
1247 /* static */ wxDateTime wxDateTime::UNow()
1248 {
1249     return wxDateTime(wxGetLocalTimeMillis());
1250 }
1251
1252 // the values in the tm structure contain the local time
1253 wxDateTime& wxDateTime::Set(const struct tm& tm)
1254 {
1255     struct tm tm2(tm);
1256     time_t timet = mktime(&tm2);
1257
1258     if ( timet == (time_t)-1 )
1259     {
1260         // mktime() rather unintuitively fails for Jan 1, 1970 if the hour is
1261         // less than timezone - try to make it work for this case
1262         if ( tm2.tm_year == 70 && tm2.tm_mon == 0 && tm2.tm_mday == 1 )
1263         {
1264             return Set((time_t)(
1265                        GetTimeZone() +
1266                        tm2.tm_hour * MIN_PER_HOUR * SEC_PER_MIN +
1267                        tm2.tm_min * SEC_PER_MIN +
1268                        tm2.tm_sec));
1269         }
1270
1271         wxFAIL_MSG( wxT("mktime() failed") );
1272
1273         *this = wxInvalidDateTime;
1274
1275         return *this;
1276     }
1277     else
1278     {
1279         return Set(timet);
1280     }
1281 }
1282
1283 wxDateTime& wxDateTime::Set(wxDateTime_t hour,
1284                             wxDateTime_t minute,
1285                             wxDateTime_t second,
1286                             wxDateTime_t millisec)
1287 {
1288     // we allow seconds to be 61 to account for the leap seconds, even if we
1289     // don't use them really
1290     wxDATETIME_CHECK( hour < 24 &&
1291                       second < 62 &&
1292                       minute < 60 &&
1293                       millisec < 1000,
1294                       wxT("Invalid time in wxDateTime::Set()") );
1295
1296     // get the current date from system
1297     struct tm tmstruct;
1298     struct tm *tm = GetTmNow(&tmstruct);
1299
1300     wxDATETIME_CHECK( tm, wxT("wxLocaltime_r() failed") );
1301
1302     // make a copy so it isn't clobbered by the call to mktime() below
1303     struct tm tm1(*tm);
1304
1305     // adjust the time
1306     tm1.tm_hour = hour;
1307     tm1.tm_min = minute;
1308     tm1.tm_sec = second;
1309
1310     // and the DST in case it changes on this date
1311     struct tm tm2(tm1);
1312     mktime(&tm2);
1313     if ( tm2.tm_isdst != tm1.tm_isdst )
1314         tm1.tm_isdst = tm2.tm_isdst;
1315
1316     (void)Set(tm1);
1317
1318     // and finally adjust milliseconds
1319     return SetMillisecond(millisec);
1320 }
1321
1322 wxDateTime& wxDateTime::Set(wxDateTime_t day,
1323                             Month        month,
1324                             int          year,
1325                             wxDateTime_t hour,
1326                             wxDateTime_t minute,
1327                             wxDateTime_t second,
1328                             wxDateTime_t millisec)
1329 {
1330     wxDATETIME_CHECK( hour < 24 &&
1331                       second < 62 &&
1332                       minute < 60 &&
1333                       millisec < 1000,
1334                       wxT("Invalid time in wxDateTime::Set()") );
1335
1336     ReplaceDefaultYearMonthWithCurrent(&year, &month);
1337
1338     wxDATETIME_CHECK( (0 < day) && (day <= GetNumberOfDays(month, year)),
1339                       wxT("Invalid date in wxDateTime::Set()") );
1340
1341     // the range of time_t type (inclusive)
1342     static const int yearMinInRange = 1970;
1343     static const int yearMaxInRange = 2037;
1344
1345     // test only the year instead of testing for the exact end of the Unix
1346     // time_t range - it doesn't bring anything to do more precise checks
1347     if ( year >= yearMinInRange && year <= yearMaxInRange )
1348     {
1349         // use the standard library version if the date is in range - this is
1350         // probably more efficient than our code
1351         struct tm tm;
1352         tm.tm_year = year - 1900;
1353         tm.tm_mon = month;
1354         tm.tm_mday = day;
1355         tm.tm_hour = hour;
1356         tm.tm_min = minute;
1357         tm.tm_sec = second;
1358         tm.tm_isdst = -1;       // mktime() will guess it
1359
1360         (void)Set(tm);
1361
1362         // and finally adjust milliseconds
1363         if (IsValid())
1364             SetMillisecond(millisec);
1365
1366         return *this;
1367     }
1368     else
1369     {
1370         // do time calculations ourselves: we want to calculate the number of
1371         // milliseconds between the given date and the epoch
1372
1373         // get the JDN for the midnight of this day
1374         m_time = GetTruncatedJDN(day, month, year);
1375         m_time -= EPOCH_JDN;
1376         m_time *= SECONDS_PER_DAY * TIME_T_FACTOR;
1377
1378         // JDN corresponds to GMT, we take localtime
1379         Add(wxTimeSpan(hour, minute, second + GetTimeZone(), millisec));
1380     }
1381
1382     return *this;
1383 }
1384
1385 wxDateTime& wxDateTime::Set(double jdn)
1386 {
1387     // so that m_time will be 0 for the midnight of Jan 1, 1970 which is jdn
1388     // EPOCH_JDN + 0.5
1389     jdn -= EPOCH_JDN + 0.5;
1390
1391     m_time.Assign(jdn*MILLISECONDS_PER_DAY);
1392
1393     // JDNs always are in UTC, so we don't need any adjustments for time zone
1394
1395     return *this;
1396 }
1397
1398 wxDateTime& wxDateTime::ResetTime()
1399 {
1400     Tm tm = GetTm();
1401
1402     if ( tm.hour || tm.min || tm.sec || tm.msec )
1403     {
1404         tm.msec =
1405         tm.sec =
1406         tm.min =
1407         tm.hour = 0;
1408
1409         Set(tm);
1410     }
1411
1412     return *this;
1413 }
1414
1415 wxDateTime wxDateTime::GetDateOnly() const
1416 {
1417     Tm tm = GetTm();
1418     tm.msec =
1419     tm.sec =
1420     tm.min =
1421     tm.hour = 0;
1422     return wxDateTime(tm);
1423 }
1424
1425 // ----------------------------------------------------------------------------
1426 // DOS Date and Time Format functions
1427 // ----------------------------------------------------------------------------
1428 // the dos date and time value is an unsigned 32 bit value in the format:
1429 // YYYYYYYMMMMDDDDDhhhhhmmmmmmsssss
1430 //
1431 // Y = year offset from 1980 (0-127)
1432 // M = month (1-12)
1433 // D = day of month (1-31)
1434 // h = hour (0-23)
1435 // m = minute (0-59)
1436 // s = bisecond (0-29) each bisecond indicates two seconds
1437 // ----------------------------------------------------------------------------
1438
1439 wxDateTime& wxDateTime::SetFromDOS(unsigned long ddt)
1440 {
1441     struct tm tm;
1442     InitTm(tm);
1443
1444     long year = ddt & 0xFE000000;
1445     year >>= 25;
1446     year += 80;
1447     tm.tm_year = year;
1448
1449     long month = ddt & 0x1E00000;
1450     month >>= 21;
1451     month -= 1;
1452     tm.tm_mon = month;
1453
1454     long day = ddt & 0x1F0000;
1455     day >>= 16;
1456     tm.tm_mday = day;
1457
1458     long hour = ddt & 0xF800;
1459     hour >>= 11;
1460     tm.tm_hour = hour;
1461
1462     long minute = ddt & 0x7E0;
1463     minute >>= 5;
1464     tm.tm_min = minute;
1465
1466     long second = ddt & 0x1F;
1467     tm.tm_sec = second * 2;
1468
1469     return Set(mktime(&tm));
1470 }
1471
1472 unsigned long wxDateTime::GetAsDOS() const
1473 {
1474     unsigned long ddt;
1475     time_t ticks = GetTicks();
1476     struct tm tmstruct;
1477     struct tm *tm = wxLocaltime_r(&ticks, &tmstruct);
1478     wxCHECK_MSG( tm, ULONG_MAX, wxT("time can't be represented in DOS format") );
1479
1480     long year = tm->tm_year;
1481     year -= 80;
1482     year <<= 25;
1483
1484     long month = tm->tm_mon;
1485     month += 1;
1486     month <<= 21;
1487
1488     long day = tm->tm_mday;
1489     day <<= 16;
1490
1491     long hour = tm->tm_hour;
1492     hour <<= 11;
1493
1494     long minute = tm->tm_min;
1495     minute <<= 5;
1496
1497     long second = tm->tm_sec;
1498     second /= 2;
1499
1500     ddt = year | month | day | hour | minute | second;
1501     return ddt;
1502 }
1503
1504 // ----------------------------------------------------------------------------
1505 // time_t <-> broken down time conversions
1506 // ----------------------------------------------------------------------------
1507
1508 wxDateTime::Tm wxDateTime::GetTm(const TimeZone& tz) const
1509 {
1510     wxASSERT_MSG( IsValid(), wxT("invalid wxDateTime") );
1511
1512     time_t time = GetTicks();
1513     if ( time != (time_t)-1 )
1514     {
1515         // use C RTL functions
1516         struct tm tmstruct;
1517         tm *tm;
1518         if ( tz.GetOffset() == -GetTimeZone() )
1519         {
1520             // we are working with local time
1521             tm = wxLocaltime_r(&time, &tmstruct);
1522
1523             // should never happen
1524             wxCHECK_MSG( tm, Tm(), wxT("wxLocaltime_r() failed") );
1525         }
1526         else
1527         {
1528             time += (time_t)tz.GetOffset();
1529 #if defined(__VMS__) || defined(__WATCOMC__) // time is unsigned so avoid warning
1530             int time2 = (int) time;
1531             if ( time2 >= 0 )
1532 #else
1533             if ( time >= 0 )
1534 #endif
1535             {
1536                 tm = wxGmtime_r(&time, &tmstruct);
1537
1538                 // should never happen
1539                 wxCHECK_MSG( tm, Tm(), wxT("wxGmtime_r() failed") );
1540             }
1541             else
1542             {
1543                 tm = (struct tm *)NULL;
1544             }
1545         }
1546
1547         if ( tm )
1548         {
1549             // adjust the milliseconds
1550             Tm tm2(*tm, tz);
1551             long timeOnly = (m_time % MILLISECONDS_PER_DAY).ToLong();
1552             tm2.msec = (wxDateTime_t)(timeOnly % 1000);
1553             return tm2;
1554         }
1555         //else: use generic code below
1556     }
1557
1558     // remember the time and do the calculations with the date only - this
1559     // eliminates rounding errors of the floating point arithmetics
1560
1561     wxLongLong timeMidnight = m_time + tz.GetOffset() * 1000;
1562
1563     long timeOnly = (timeMidnight % MILLISECONDS_PER_DAY).ToLong();
1564
1565     // we want to always have positive time and timeMidnight to be really
1566     // the midnight before it
1567     if ( timeOnly < 0 )
1568     {
1569         timeOnly = MILLISECONDS_PER_DAY + timeOnly;
1570     }
1571
1572     timeMidnight -= timeOnly;
1573
1574     // calculate the Gregorian date from JDN for the midnight of our date:
1575     // this will yield day, month (in 1..12 range) and year
1576
1577     // actually, this is the JDN for the noon of the previous day
1578     long jdn = (timeMidnight / MILLISECONDS_PER_DAY).ToLong() + EPOCH_JDN;
1579
1580     // CREDIT: code below is by Scott E. Lee (but bugs are mine)
1581
1582     wxASSERT_MSG( jdn > -2, wxT("JDN out of range") );
1583
1584     // calculate the century
1585     long temp = (jdn + JDN_OFFSET) * 4 - 1;
1586     long century = temp / DAYS_PER_400_YEARS;
1587
1588     // then the year and day of year (1 <= dayOfYear <= 366)
1589     temp = ((temp % DAYS_PER_400_YEARS) / 4) * 4 + 3;
1590     long year = (century * 100) + (temp / DAYS_PER_4_YEARS);
1591     long dayOfYear = (temp % DAYS_PER_4_YEARS) / 4 + 1;
1592
1593     // and finally the month and day of the month
1594     temp = dayOfYear * 5 - 3;
1595     long month = temp / DAYS_PER_5_MONTHS;
1596     long day = (temp % DAYS_PER_5_MONTHS) / 5 + 1;
1597
1598     // month is counted from March - convert to normal
1599     if ( month < 10 )
1600     {
1601         month += 3;
1602     }
1603     else
1604     {
1605         year += 1;
1606         month -= 9;
1607     }
1608
1609     // year is offset by 4800
1610     year -= 4800;
1611
1612     // check that the algorithm gave us something reasonable
1613     wxASSERT_MSG( (0 < month) && (month <= 12), wxT("invalid month") );
1614     wxASSERT_MSG( (1 <= day) && (day < 32), wxT("invalid day") );
1615
1616     // construct Tm from these values
1617     Tm tm;
1618     tm.year = (int)year;
1619     tm.yday = (wxDateTime_t)(dayOfYear - 1); // use C convention for day number
1620     tm.mon = (Month)(month - 1); // algorithm yields 1 for January, not 0
1621     tm.mday = (wxDateTime_t)day;
1622     tm.msec = (wxDateTime_t)(timeOnly % 1000);
1623     timeOnly -= tm.msec;
1624     timeOnly /= 1000;               // now we have time in seconds
1625
1626     tm.sec = (wxDateTime_t)(timeOnly % SEC_PER_MIN);
1627     timeOnly -= tm.sec;
1628     timeOnly /= SEC_PER_MIN;        // now we have time in minutes
1629
1630     tm.min = (wxDateTime_t)(timeOnly % MIN_PER_HOUR);
1631     timeOnly -= tm.min;
1632
1633     tm.hour = (wxDateTime_t)(timeOnly / MIN_PER_HOUR);
1634
1635     return tm;
1636 }
1637
1638 wxDateTime& wxDateTime::SetYear(int year)
1639 {
1640     wxASSERT_MSG( IsValid(), wxT("invalid wxDateTime") );
1641
1642     Tm tm(GetTm());
1643     tm.year = year;
1644     Set(tm);
1645
1646     return *this;
1647 }
1648
1649 wxDateTime& wxDateTime::SetMonth(Month month)
1650 {
1651     wxASSERT_MSG( IsValid(), wxT("invalid wxDateTime") );
1652
1653     Tm tm(GetTm());
1654     tm.mon = month;
1655     Set(tm);
1656
1657     return *this;
1658 }
1659
1660 wxDateTime& wxDateTime::SetDay(wxDateTime_t mday)
1661 {
1662     wxASSERT_MSG( IsValid(), wxT("invalid wxDateTime") );
1663
1664     Tm tm(GetTm());
1665     tm.mday = mday;
1666     Set(tm);
1667
1668     return *this;
1669 }
1670
1671 wxDateTime& wxDateTime::SetHour(wxDateTime_t hour)
1672 {
1673     wxASSERT_MSG( IsValid(), wxT("invalid wxDateTime") );
1674
1675     Tm tm(GetTm());
1676     tm.hour = hour;
1677     Set(tm);
1678
1679     return *this;
1680 }
1681
1682 wxDateTime& wxDateTime::SetMinute(wxDateTime_t min)
1683 {
1684     wxASSERT_MSG( IsValid(), wxT("invalid wxDateTime") );
1685
1686     Tm tm(GetTm());
1687     tm.min = min;
1688     Set(tm);
1689
1690     return *this;
1691 }
1692
1693 wxDateTime& wxDateTime::SetSecond(wxDateTime_t sec)
1694 {
1695     wxASSERT_MSG( IsValid(), wxT("invalid wxDateTime") );
1696
1697     Tm tm(GetTm());
1698     tm.sec = sec;
1699     Set(tm);
1700
1701     return *this;
1702 }
1703
1704 wxDateTime& wxDateTime::SetMillisecond(wxDateTime_t millisecond)
1705 {
1706     wxASSERT_MSG( IsValid(), wxT("invalid wxDateTime") );
1707
1708     // we don't need to use GetTm() for this one
1709     m_time -= m_time % 1000l;
1710     m_time += millisecond;
1711
1712     return *this;
1713 }
1714
1715 // ----------------------------------------------------------------------------
1716 // wxDateTime arithmetics
1717 // ----------------------------------------------------------------------------
1718
1719 wxDateTime& wxDateTime::Add(const wxDateSpan& diff)
1720 {
1721     Tm tm(GetTm());
1722
1723     tm.year += diff.GetYears();
1724     tm.AddMonths(diff.GetMonths());
1725
1726     // check that the resulting date is valid
1727     if ( tm.mday > GetNumOfDaysInMonth(tm.year, tm.mon) )
1728     {
1729         // We suppose that when adding one month to Jan 31 we want to get Feb
1730         // 28 (or 29), i.e. adding a month to the last day of the month should
1731         // give the last day of the next month which is quite logical.
1732         //
1733         // Unfortunately, there is no logic way to understand what should
1734         // Jan 30 + 1 month be - Feb 28 too or Feb 27 (assuming non leap year)?
1735         // We make it Feb 28 (last day too), but it is highly questionable.
1736         tm.mday = GetNumOfDaysInMonth(tm.year, tm.mon);
1737     }
1738
1739     tm.AddDays(diff.GetTotalDays());
1740
1741     Set(tm);
1742
1743     wxASSERT_MSG( IsSameTime(tm),
1744                   wxT("Add(wxDateSpan) shouldn't modify time") );
1745
1746     return *this;
1747 }
1748
1749 // ----------------------------------------------------------------------------
1750 // Weekday and monthday stuff
1751 // ----------------------------------------------------------------------------
1752
1753 // convert Sun, Mon, ..., Sat into 6, 0, ..., 5
1754 static inline int ConvertWeekDayToMondayBase(int wd)
1755 {
1756     return wd == wxDateTime::Sun ? 6 : wd - 1;
1757 }
1758
1759 /* static */
1760 wxDateTime
1761 wxDateTime::SetToWeekOfYear(int year, wxDateTime_t numWeek, WeekDay wd)
1762 {
1763     wxASSERT_MSG( numWeek > 0,
1764                   wxT("invalid week number: weeks are counted from 1") );
1765
1766     // Jan 4 always lies in the 1st week of the year
1767     wxDateTime dt(4, Jan, year);
1768     dt.SetToWeekDayInSameWeek(wd);
1769     dt += wxDateSpan::Weeks(numWeek - 1);
1770
1771     return dt;
1772 }
1773
1774 #if WXWIN_COMPATIBILITY_2_6
1775 // use a separate function to avoid warnings about using deprecated
1776 // SetToTheWeek in GetWeek below
1777 static wxDateTime
1778 SetToTheWeek(int year,
1779              wxDateTime::wxDateTime_t numWeek,
1780              wxDateTime::WeekDay weekday,
1781              wxDateTime::WeekFlags flags)
1782 {
1783     // Jan 4 always lies in the 1st week of the year
1784     wxDateTime dt(4, wxDateTime::Jan, year);
1785     dt.SetToWeekDayInSameWeek(weekday, flags);
1786     dt += wxDateSpan::Weeks(numWeek - 1);
1787
1788     return dt;
1789 }
1790
1791 bool wxDateTime::SetToTheWeek(wxDateTime_t numWeek,
1792                               WeekDay weekday,
1793                               WeekFlags flags)
1794 {
1795     int year = GetYear();
1796     *this = ::SetToTheWeek(year, numWeek, weekday, flags);
1797     if ( GetYear() != year )
1798     {
1799         // oops... numWeek was too big
1800         return false;
1801     }
1802
1803     return true;
1804 }
1805
1806 wxDateTime wxDateTime::GetWeek(wxDateTime_t numWeek,
1807                                WeekDay weekday,
1808                                WeekFlags flags) const
1809 {
1810     return ::SetToTheWeek(GetYear(), numWeek, weekday, flags);
1811 }
1812 #endif // WXWIN_COMPATIBILITY_2_6
1813
1814 wxDateTime& wxDateTime::SetToLastMonthDay(Month month,
1815                                           int year)
1816 {
1817     // take the current month/year if none specified
1818     if ( year == Inv_Year )
1819         year = GetYear();
1820     if ( month == Inv_Month )
1821         month = GetMonth();
1822
1823     return Set(GetNumOfDaysInMonth(year, month), month, year);
1824 }
1825
1826 wxDateTime& wxDateTime::SetToWeekDayInSameWeek(WeekDay weekday, WeekFlags flags)
1827 {
1828     wxDATETIME_CHECK( weekday != Inv_WeekDay, wxT("invalid weekday") );
1829
1830     int wdayDst = weekday,
1831         wdayThis = GetWeekDay();
1832     if ( wdayDst == wdayThis )
1833     {
1834         // nothing to do
1835         return *this;
1836     }
1837
1838     if ( flags == Default_First )
1839     {
1840         flags = GetCountry() == USA ? Sunday_First : Monday_First;
1841     }
1842
1843     // the logic below based on comparing weekday and wdayThis works if Sun (0)
1844     // is the first day in the week, but breaks down for Monday_First case so
1845     // we adjust the week days in this case
1846     if ( flags == Monday_First )
1847     {
1848         if ( wdayThis == Sun )
1849             wdayThis += 7;
1850         if ( wdayDst == Sun )
1851             wdayDst += 7;
1852     }
1853     //else: Sunday_First, nothing to do
1854
1855     // go forward or back in time to the day we want
1856     if ( wdayDst < wdayThis )
1857     {
1858         return Subtract(wxDateSpan::Days(wdayThis - wdayDst));
1859     }
1860     else // weekday > wdayThis
1861     {
1862         return Add(wxDateSpan::Days(wdayDst - wdayThis));
1863     }
1864 }
1865
1866 wxDateTime& wxDateTime::SetToNextWeekDay(WeekDay weekday)
1867 {
1868     wxDATETIME_CHECK( weekday != Inv_WeekDay, wxT("invalid weekday") );
1869
1870     int diff;
1871     WeekDay wdayThis = GetWeekDay();
1872     if ( weekday == wdayThis )
1873     {
1874         // nothing to do
1875         return *this;
1876     }
1877     else if ( weekday < wdayThis )
1878     {
1879         // need to advance a week
1880         diff = 7 - (wdayThis - weekday);
1881     }
1882     else // weekday > wdayThis
1883     {
1884         diff = weekday - wdayThis;
1885     }
1886
1887     return Add(wxDateSpan::Days(diff));
1888 }
1889
1890 wxDateTime& wxDateTime::SetToPrevWeekDay(WeekDay weekday)
1891 {
1892     wxDATETIME_CHECK( weekday != Inv_WeekDay, wxT("invalid weekday") );
1893
1894     int diff;
1895     WeekDay wdayThis = GetWeekDay();
1896     if ( weekday == wdayThis )
1897     {
1898         // nothing to do
1899         return *this;
1900     }
1901     else if ( weekday > wdayThis )
1902     {
1903         // need to go to previous week
1904         diff = 7 - (weekday - wdayThis);
1905     }
1906     else // weekday < wdayThis
1907     {
1908         diff = wdayThis - weekday;
1909     }
1910
1911     return Subtract(wxDateSpan::Days(diff));
1912 }
1913
1914 bool wxDateTime::SetToWeekDay(WeekDay weekday,
1915                               int n,
1916                               Month month,
1917                               int year)
1918 {
1919     wxCHECK_MSG( weekday != Inv_WeekDay, false, wxT("invalid weekday") );
1920
1921     // we don't check explicitly that -5 <= n <= 5 because we will return false
1922     // anyhow in such case - but may be should still give an assert for it?
1923
1924     // take the current month/year if none specified
1925     ReplaceDefaultYearMonthWithCurrent(&year, &month);
1926
1927     wxDateTime dt;
1928
1929     // TODO this probably could be optimised somehow...
1930
1931     if ( n > 0 )
1932     {
1933         // get the first day of the month
1934         dt.Set(1, month, year);
1935
1936         // get its wday
1937         WeekDay wdayFirst = dt.GetWeekDay();
1938
1939         // go to the first weekday of the month
1940         int diff = weekday - wdayFirst;
1941         if ( diff < 0 )
1942             diff += 7;
1943
1944         // add advance n-1 weeks more
1945         diff += 7*(n - 1);
1946
1947         dt += wxDateSpan::Days(diff);
1948     }
1949     else // count from the end of the month
1950     {
1951         // get the last day of the month
1952         dt.SetToLastMonthDay(month, year);
1953
1954         // get its wday
1955         WeekDay wdayLast = dt.GetWeekDay();
1956
1957         // go to the last weekday of the month
1958         int diff = wdayLast - weekday;
1959         if ( diff < 0 )
1960             diff += 7;
1961
1962         // and rewind n-1 weeks from there
1963         diff += 7*(-n - 1);
1964
1965         dt -= wxDateSpan::Days(diff);
1966     }
1967
1968     // check that it is still in the same month
1969     if ( dt.GetMonth() == month )
1970     {
1971         *this = dt;
1972
1973         return true;
1974     }
1975     else
1976     {
1977         // no such day in this month
1978         return false;
1979     }
1980 }
1981
1982 static inline
1983 wxDateTime::wxDateTime_t GetDayOfYearFromTm(const wxDateTime::Tm& tm)
1984 {
1985     return (wxDateTime::wxDateTime_t)(gs_cumulatedDays[wxDateTime::IsLeapYear(tm.year)][tm.mon] + tm.mday);
1986 }
1987
1988 wxDateTime::wxDateTime_t wxDateTime::GetDayOfYear(const TimeZone& tz) const
1989 {
1990     return GetDayOfYearFromTm(GetTm(tz));
1991 }
1992
1993 wxDateTime::wxDateTime_t
1994 wxDateTime::GetWeekOfYear(wxDateTime::WeekFlags flags, const TimeZone& tz) const
1995 {
1996     if ( flags == Default_First )
1997     {
1998         flags = GetCountry() == USA ? Sunday_First : Monday_First;
1999     }
2000
2001     Tm tm(GetTm(tz));
2002     wxDateTime_t nDayInYear = GetDayOfYearFromTm(tm);
2003
2004     int wdTarget = GetWeekDay(tz);
2005     int wdYearStart = wxDateTime(1, Jan, GetYear()).GetWeekDay();
2006     int week;
2007     if ( flags == Sunday_First )
2008     {
2009         // FIXME: First week is not calculated correctly.
2010         week = (nDayInYear - wdTarget + 7) / 7;
2011         if ( wdYearStart == Wed || wdYearStart == Thu )
2012             week++;
2013     }
2014     else // week starts with monday
2015     {
2016         // adjust the weekdays to non-US style.
2017         wdYearStart = ConvertWeekDayToMondayBase(wdYearStart);
2018         wdTarget = ConvertWeekDayToMondayBase(wdTarget);
2019
2020         // quoting from http://www.cl.cam.ac.uk/~mgk25/iso-time.html:
2021         //
2022         //      Week 01 of a year is per definition the first week that has the
2023         //      Thursday in this year, which is equivalent to the week that
2024         //      contains the fourth day of January. In other words, the first
2025         //      week of a new year is the week that has the majority of its
2026         //      days in the new year. Week 01 might also contain days from the
2027         //      previous year and the week before week 01 of a year is the last
2028         //      week (52 or 53) of the previous year even if it contains days
2029         //      from the new year. A week starts with Monday (day 1) and ends
2030         //      with Sunday (day 7).
2031         //
2032
2033         // if Jan 1 is Thursday or less, it is in the first week of this year
2034         if ( wdYearStart < 4 )
2035         {
2036             // count the number of entire weeks between Jan 1 and this date
2037             week = (nDayInYear + wdYearStart + 6 - wdTarget)/7;
2038
2039             // be careful to check for overflow in the next year
2040             if ( week == 53 && tm.mday - wdTarget > 28 )
2041                     week = 1;
2042         }
2043         else // Jan 1 is in the last week of the previous year
2044         {
2045             // check if we happen to be at the last week of previous year:
2046             if ( tm.mon == Jan && tm.mday < 8 - wdYearStart )
2047                 week = wxDateTime(31, Dec, GetYear()-1).GetWeekOfYear();
2048             else
2049                 week = (nDayInYear + wdYearStart - 1 - wdTarget)/7;
2050         }
2051     }
2052
2053     return (wxDateTime::wxDateTime_t)week;
2054 }
2055
2056 wxDateTime::wxDateTime_t wxDateTime::GetWeekOfMonth(wxDateTime::WeekFlags flags,
2057                                                     const TimeZone& tz) const
2058 {
2059     Tm tm = GetTm(tz);
2060     const wxDateTime dateFirst = wxDateTime(1, tm.mon, tm.year);
2061     const wxDateTime::WeekDay wdFirst = dateFirst.GetWeekDay();
2062
2063     if ( flags == Default_First )
2064     {
2065         flags = GetCountry() == USA ? Sunday_First : Monday_First;
2066     }
2067
2068     // compute offset of dateFirst from the beginning of the week
2069     int firstOffset;
2070     if ( flags == Sunday_First )
2071         firstOffset = wdFirst - Sun;
2072     else
2073         firstOffset = wdFirst == Sun ? DAYS_PER_WEEK - 1 : wdFirst - Mon;
2074
2075     return (wxDateTime::wxDateTime_t)((tm.mday - 1 + firstOffset)/7 + 1);
2076 }
2077
2078 wxDateTime& wxDateTime::SetToYearDay(wxDateTime::wxDateTime_t yday)
2079 {
2080     int year = GetYear();
2081     wxDATETIME_CHECK( (0 < yday) && (yday <= GetNumberOfDays(year)),
2082                       wxT("invalid year day") );
2083
2084     bool isLeap = IsLeapYear(year);
2085     for ( Month mon = Jan; mon < Inv_Month; wxNextMonth(mon) )
2086     {
2087         // for Dec, we can't compare with gs_cumulatedDays[mon + 1], but we
2088         // don't need it neither - because of the CHECK above we know that
2089         // yday lies in December then
2090         if ( (mon == Dec) || (yday <= gs_cumulatedDays[isLeap][mon + 1]) )
2091         {
2092             Set((wxDateTime::wxDateTime_t)(yday - gs_cumulatedDays[isLeap][mon]), mon, year);
2093
2094             break;
2095         }
2096     }
2097
2098     return *this;
2099 }
2100
2101 // ----------------------------------------------------------------------------
2102 // Julian day number conversion and related stuff
2103 // ----------------------------------------------------------------------------
2104
2105 double wxDateTime::GetJulianDayNumber() const
2106 {
2107     return m_time.ToDouble() / MILLISECONDS_PER_DAY + EPOCH_JDN + 0.5;
2108 }
2109
2110 double wxDateTime::GetRataDie() const
2111 {
2112     // March 1 of the year 0 is Rata Die day -306 and JDN 1721119.5
2113     return GetJulianDayNumber() - 1721119.5 - 306;
2114 }
2115
2116 // ----------------------------------------------------------------------------
2117 // timezone and DST stuff
2118 // ----------------------------------------------------------------------------
2119
2120 int wxDateTime::IsDST(wxDateTime::Country country) const
2121 {
2122     wxCHECK_MSG( country == Country_Default, -1,
2123                  wxT("country support not implemented") );
2124
2125     // use the C RTL for the dates in the standard range
2126     time_t timet = GetTicks();
2127     if ( timet != (time_t)-1 )
2128     {
2129         struct tm tmstruct;
2130         tm *tm = wxLocaltime_r(&timet, &tmstruct);
2131
2132         wxCHECK_MSG( tm, -1, wxT("wxLocaltime_r() failed") );
2133
2134         return tm->tm_isdst;
2135     }
2136     else
2137     {
2138         int year = GetYear();
2139
2140         if ( !IsDSTApplicable(year, country) )
2141         {
2142             // no DST time in this year in this country
2143             return -1;
2144         }
2145
2146         return IsBetween(GetBeginDST(year, country), GetEndDST(year, country));
2147     }
2148 }
2149
2150 wxDateTime& wxDateTime::MakeTimezone(const TimeZone& tz, bool noDST)
2151 {
2152     long secDiff = GetTimeZone() + tz.GetOffset();
2153
2154     // we need to know whether DST is or not in effect for this date unless
2155     // the test disabled by the caller
2156     if ( !noDST && (IsDST() == 1) )
2157     {
2158         // FIXME we assume that the DST is always shifted by 1 hour
2159         secDiff -= 3600;
2160     }
2161
2162     return Add(wxTimeSpan::Seconds(secDiff));
2163 }
2164
2165 wxDateTime& wxDateTime::MakeFromTimezone(const TimeZone& tz, bool noDST)
2166 {
2167     long secDiff = GetTimeZone() + tz.GetOffset();
2168
2169     // we need to know whether DST is or not in effect for this date unless
2170     // the test disabled by the caller
2171     if ( !noDST && (IsDST() == 1) )
2172     {
2173         // FIXME we assume that the DST is always shifted by 1 hour
2174         secDiff -= 3600;
2175     }
2176
2177     return Subtract(wxTimeSpan::Seconds(secDiff));
2178 }
2179
2180 // ============================================================================
2181 // wxDateTimeHolidayAuthority and related classes
2182 // ============================================================================
2183
2184 #include "wx/arrimpl.cpp"
2185
2186 WX_DEFINE_OBJARRAY(wxDateTimeArray)
2187
2188 static int wxCMPFUNC_CONV
2189 wxDateTimeCompareFunc(wxDateTime **first, wxDateTime **second)
2190 {
2191     wxDateTime dt1 = **first,
2192                dt2 = **second;
2193
2194     return dt1 == dt2 ? 0 : dt1 < dt2 ? -1 : +1;
2195 }
2196
2197 // ----------------------------------------------------------------------------
2198 // wxDateTimeHolidayAuthority
2199 // ----------------------------------------------------------------------------
2200
2201 wxHolidayAuthoritiesArray wxDateTimeHolidayAuthority::ms_authorities;
2202
2203 /* static */
2204 bool wxDateTimeHolidayAuthority::IsHoliday(const wxDateTime& dt)
2205 {
2206     size_t count = ms_authorities.size();
2207     for ( size_t n = 0; n < count; n++ )
2208     {
2209         if ( ms_authorities[n]->DoIsHoliday(dt) )
2210         {
2211             return true;
2212         }
2213     }
2214
2215     return false;
2216 }
2217
2218 /* static */
2219 size_t
2220 wxDateTimeHolidayAuthority::GetHolidaysInRange(const wxDateTime& dtStart,
2221                                                const wxDateTime& dtEnd,
2222                                                wxDateTimeArray& holidays)
2223 {
2224     wxDateTimeArray hol;
2225
2226     holidays.Clear();
2227
2228     const size_t countAuth = ms_authorities.size();
2229     for ( size_t nAuth = 0; nAuth < countAuth; nAuth++ )
2230     {
2231         ms_authorities[nAuth]->DoGetHolidaysInRange(dtStart, dtEnd, hol);
2232
2233         WX_APPEND_ARRAY(holidays, hol);
2234     }
2235
2236     holidays.Sort(wxDateTimeCompareFunc);
2237
2238     return holidays.size();
2239 }
2240
2241 /* static */
2242 void wxDateTimeHolidayAuthority::ClearAllAuthorities()
2243 {
2244     WX_CLEAR_ARRAY(ms_authorities);
2245 }
2246
2247 /* static */
2248 void wxDateTimeHolidayAuthority::AddAuthority(wxDateTimeHolidayAuthority *auth)
2249 {
2250     ms_authorities.push_back(auth);
2251 }
2252
2253 wxDateTimeHolidayAuthority::~wxDateTimeHolidayAuthority()
2254 {
2255     // required here for Darwin
2256 }
2257
2258 // ----------------------------------------------------------------------------
2259 // wxDateTimeWorkDays
2260 // ----------------------------------------------------------------------------
2261
2262 bool wxDateTimeWorkDays::DoIsHoliday(const wxDateTime& dt) const
2263 {
2264     wxDateTime::WeekDay wd = dt.GetWeekDay();
2265
2266     return (wd == wxDateTime::Sun) || (wd == wxDateTime::Sat);
2267 }
2268
2269 size_t wxDateTimeWorkDays::DoGetHolidaysInRange(const wxDateTime& dtStart,
2270                                                 const wxDateTime& dtEnd,
2271                                                 wxDateTimeArray& holidays) const
2272 {
2273     if ( dtStart > dtEnd )
2274     {
2275         wxFAIL_MSG( wxT("invalid date range in GetHolidaysInRange") );
2276
2277         return 0u;
2278     }
2279
2280     holidays.Empty();
2281
2282     // instead of checking all days, start with the first Sat after dtStart and
2283     // end with the last Sun before dtEnd
2284     wxDateTime dtSatFirst = dtStart.GetNextWeekDay(wxDateTime::Sat),
2285                dtSatLast = dtEnd.GetPrevWeekDay(wxDateTime::Sat),
2286                dtSunFirst = dtStart.GetNextWeekDay(wxDateTime::Sun),
2287                dtSunLast = dtEnd.GetPrevWeekDay(wxDateTime::Sun),
2288                dt;
2289
2290     for ( dt = dtSatFirst; dt <= dtSatLast; dt += wxDateSpan::Week() )
2291     {
2292         holidays.Add(dt);
2293     }
2294
2295     for ( dt = dtSunFirst; dt <= dtSunLast; dt += wxDateSpan::Week() )
2296     {
2297         holidays.Add(dt);
2298     }
2299
2300     return holidays.GetCount();
2301 }
2302
2303 // ============================================================================
2304 // other helper functions
2305 // ============================================================================
2306
2307 // ----------------------------------------------------------------------------
2308 // iteration helpers: can be used to write a for loop over enum variable like
2309 // this:
2310 //  for ( m = wxDateTime::Jan; m < wxDateTime::Inv_Month; wxNextMonth(m) )
2311 // ----------------------------------------------------------------------------
2312
2313 WXDLLIMPEXP_BASE void wxNextMonth(wxDateTime::Month& m)
2314 {
2315     wxASSERT_MSG( m < wxDateTime::Inv_Month, wxT("invalid month") );
2316
2317     // no wrapping or the for loop above would never end!
2318     m = (wxDateTime::Month)(m + 1);
2319 }
2320
2321 WXDLLIMPEXP_BASE void wxPrevMonth(wxDateTime::Month& m)
2322 {
2323     wxASSERT_MSG( m < wxDateTime::Inv_Month, wxT("invalid month") );
2324
2325     m = m == wxDateTime::Jan ? wxDateTime::Inv_Month
2326                              : (wxDateTime::Month)(m - 1);
2327 }
2328
2329 WXDLLIMPEXP_BASE void wxNextWDay(wxDateTime::WeekDay& wd)
2330 {
2331     wxASSERT_MSG( wd < wxDateTime::Inv_WeekDay, wxT("invalid week day") );
2332
2333     // no wrapping or the for loop above would never end!
2334     wd = (wxDateTime::WeekDay)(wd + 1);
2335 }
2336
2337 WXDLLIMPEXP_BASE void wxPrevWDay(wxDateTime::WeekDay& wd)
2338 {
2339     wxASSERT_MSG( wd < wxDateTime::Inv_WeekDay, wxT("invalid week day") );
2340
2341     wd = wd == wxDateTime::Sun ? wxDateTime::Inv_WeekDay
2342                                : (wxDateTime::WeekDay)(wd - 1);
2343 }
2344
2345 #ifdef __WXMSW__
2346
2347 wxDateTime& wxDateTime::SetFromMSWSysTime(const SYSTEMTIME& st)
2348 {
2349     return Set(st.wDay,
2350             static_cast<wxDateTime::Month>(wxDateTime::Jan + st.wMonth - 1),
2351             st.wYear,
2352             st.wHour, st.wMinute, st.wSecond, st.wMilliseconds);
2353 }
2354
2355 wxDateTime& wxDateTime::SetFromMSWSysDate(const SYSTEMTIME& st)
2356 {
2357     return Set(st.wDay,
2358             static_cast<wxDateTime::Month>(wxDateTime::Jan + st.wMonth - 1),
2359             st.wYear,
2360             0, 0, 0, 0);
2361 }
2362
2363 void wxDateTime::GetAsMSWSysTime(SYSTEMTIME* st) const
2364 {
2365     const wxDateTime::Tm tm(GetTm());
2366
2367     st->wYear = (WXWORD)tm.year;
2368     st->wMonth = (WXWORD)(tm.mon - wxDateTime::Jan + 1);
2369     st->wDay = tm.mday;
2370
2371     st->wDayOfWeek = 0;
2372     st->wHour = tm.hour;
2373     st->wMinute = tm.min;
2374     st->wSecond = tm.sec;
2375     st->wMilliseconds = tm.msec;
2376 }
2377
2378 void wxDateTime::GetAsMSWSysDate(SYSTEMTIME* st) const
2379 {
2380     const wxDateTime::Tm tm(GetTm());
2381
2382     st->wYear = (WXWORD)tm.year;
2383     st->wMonth = (WXWORD)(tm.mon - wxDateTime::Jan + 1);
2384     st->wDay = tm.mday;
2385
2386     st->wDayOfWeek =
2387     st->wHour =
2388     st->wMinute =
2389     st->wSecond =
2390     st->wMilliseconds = 0;
2391 }
2392
2393 #endif // __WXMSW__
2394
2395 #endif // wxUSE_DATETIME