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      1 /*
      2 *******************************************************************************
      3 * Copyright (C) 1997-2010, International Business Machines Corporation and    *
      4 * others. All Rights Reserved.                                                *
      5 *******************************************************************************
      6 *
      7 * File GREGOCAL.CPP
      8 *
      9 * Modification History:
     10 *
     11 *   Date        Name        Description
     12 *   02/05/97    clhuang     Creation.
     13 *   03/28/97    aliu        Made highly questionable fix to computeFields to
     14 *                           handle DST correctly.
     15 *   04/22/97    aliu        Cleaned up code drastically.  Added monthLength().
     16 *                           Finished unimplemented parts of computeTime() for
     17 *                           week-based date determination.  Removed quetionable
     18 *                           fix and wrote correct fix for computeFields() and
     19 *                           daylight time handling.  Rewrote inDaylightTime()
     20 *                           and computeFields() to handle sensitive Daylight to
     21 *                           Standard time transitions correctly.
     22 *   05/08/97    aliu        Added code review changes.  Fixed isLeapYear() to
     23 *                           not cutover.
     24 *   08/12/97    aliu        Added equivalentTo.  Misc other fixes.  Updated
     25 *                           add() from Java source.
     26 *    07/28/98    stephen        Sync up with JDK 1.2
     27 *    09/14/98    stephen        Changed type of kOneDay, kOneWeek to double.
     28 *                            Fixed bug in roll()
     29 *   10/15/99    aliu        Fixed j31, incorrect WEEK_OF_YEAR computation.
     30 *   10/15/99    aliu        Fixed j32, cannot set date to Feb 29 2000 AD.
     31 *                           {JDK bug 4210209 4209272}
     32 *   11/15/99    weiv        Added YEAR_WOY and DOW_LOCAL computation
     33 *                           to timeToFields method, updated kMinValues, kMaxValues & kLeastMaxValues
     34 *   12/09/99    aliu        Fixed j81, calculation errors and roll bugs
     35 *                           in year of cutover.
     36 *   01/24/2000  aliu        Revised computeJulianDay for YEAR YEAR_WOY WOY.
     37 ********************************************************************************
     38 */
     39 
     40 #include "unicode/utypes.h"
     41 #include <float.h>
     42 
     43 #if !UCONFIG_NO_FORMATTING
     44 
     45 #include "unicode/gregocal.h"
     46 #include "gregoimp.h"
     47 #include "umutex.h"
     48 #include "uassert.h"
     49 
     50 // *****************************************************************************
     51 // class GregorianCalendar
     52 // *****************************************************************************
     53 
     54 /**
     55 * Note that the Julian date used here is not a true Julian date, since
     56 * it is measured from midnight, not noon.  This value is the Julian
     57 * day number of January 1, 1970 (Gregorian calendar) at noon UTC. [LIU]
     58 */
     59 
     60 static const int16_t kNumDays[]
     61 = {0,31,59,90,120,151,181,212,243,273,304,334}; // 0-based, for day-in-year
     62 static const int16_t kLeapNumDays[]
     63 = {0,31,60,91,121,152,182,213,244,274,305,335}; // 0-based, for day-in-year
     64 static const int8_t kMonthLength[]
     65 = {31,28,31,30,31,30,31,31,30,31,30,31}; // 0-based
     66 static const int8_t kLeapMonthLength[]
     67 = {31,29,31,30,31,30,31,31,30,31,30,31}; // 0-based
     68 
     69 // setTimeInMillis() limits the Julian day range to +/-7F000000.
     70 // This would seem to limit the year range to:
     71 //  ms=+183882168921600000  jd=7f000000  December 20, 5828963 AD
     72 //  ms=-184303902528000000  jd=81000000  September 20, 5838270 BC
     73 // HOWEVER, CalendarRegressionTest/Test4167060 shows that the actual
     74 // range limit on the year field is smaller (~ +/-140000). [alan 3.0]
     75 
     76 static const int32_t kGregorianCalendarLimits[UCAL_FIELD_COUNT][4] = {
     77     // Minimum  Greatest    Least  Maximum
     78     //           Minimum  Maximum
     79     {        0,        0,        1,        1}, // ERA
     80     {        1,        1,   140742,   144683}, // YEAR
     81     {        0,        0,       11,       11}, // MONTH
     82     {        1,        1,       52,       53}, // WEEK_OF_YEAR
     83     {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // WEEK_OF_MONTH
     84     {        1,        1,       28,       31}, // DAY_OF_MONTH
     85     {        1,        1,      365,      366}, // DAY_OF_YEAR
     86     {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // DAY_OF_WEEK
     87     {       -1,       -1,        4,        5}, // DAY_OF_WEEK_IN_MONTH
     88     {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // AM_PM
     89     {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // HOUR
     90     {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // HOUR_OF_DAY
     91     {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // MINUTE
     92     {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // SECOND
     93     {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // MILLISECOND
     94     {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // ZONE_OFFSET
     95     {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // DST_OFFSET
     96     {  -140742,  -140742,   140742,   144683}, // YEAR_WOY
     97     {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // DOW_LOCAL
     98     {  -140742,  -140742,   140742,   144683}, // EXTENDED_YEAR
     99     {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // JULIAN_DAY
    100     {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // MILLISECONDS_IN_DAY
    101     {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // IS_LEAP_MONTH
    102 };
    103 
    104 /*
    105 * <pre>
    106 *                            Greatest       Least
    107 * Field name        Minimum   Minimum     Maximum     Maximum
    108 * ----------        -------   -------     -------     -------
    109 * ERA                     0         0           1           1
    110 * YEAR                    1         1      140742      144683
    111 * MONTH                   0         0          11          11
    112 * WEEK_OF_YEAR            1         1          52          53
    113 * WEEK_OF_MONTH           0         0           4           6
    114 * DAY_OF_MONTH            1         1          28          31
    115 * DAY_OF_YEAR             1         1         365         366
    116 * DAY_OF_WEEK             1         1           7           7
    117 * DAY_OF_WEEK_IN_MONTH   -1        -1           4           5
    118 * AM_PM                   0         0           1           1
    119 * HOUR                    0         0          11          11
    120 * HOUR_OF_DAY             0         0          23          23
    121 * MINUTE                  0         0          59          59
    122 * SECOND                  0         0          59          59
    123 * MILLISECOND             0         0         999         999
    124 * ZONE_OFFSET           -12*      -12*         12*         12*
    125 * DST_OFFSET              0         0           1*          1*
    126 * YEAR_WOY                1         1      140742      144683
    127 * DOW_LOCAL               1         1           7           7
    128 * </pre>
    129 * (*) In units of one-hour
    130 */
    131 
    132 #if defined( U_DEBUG_CALSVC ) || defined (U_DEBUG_CAL)
    133 #include <stdio.h>
    134 #endif
    135 
    136 U_NAMESPACE_BEGIN
    137 
    138 UOBJECT_DEFINE_RTTI_IMPLEMENTATION(GregorianCalendar)
    139 
    140 // 00:00:00 UTC, October 15, 1582, expressed in ms from the epoch.
    141 // Note that only Italy and other Catholic countries actually
    142 // observed this cutover.  Most other countries followed in
    143 // the next few centuries, some as late as 1928. [LIU]
    144 // in Java, -12219292800000L
    145 //const UDate GregorianCalendar::kPapalCutover = -12219292800000L;
    146 static const uint32_t kCutoverJulianDay = 2299161;
    147 static const UDate kPapalCutover = (2299161.0 - kEpochStartAsJulianDay) * U_MILLIS_PER_DAY;
    148 //static const UDate kPapalCutoverJulian = (2299161.0 - kEpochStartAsJulianDay);
    149 
    150 // -------------------------------------
    151 
    152 GregorianCalendar::GregorianCalendar(UErrorCode& status)
    153 :   Calendar(status),
    154 fGregorianCutover(kPapalCutover),
    155 fCutoverJulianDay(kCutoverJulianDay), fNormalizedGregorianCutover(fGregorianCutover), fGregorianCutoverYear(1582),
    156 fIsGregorian(TRUE), fInvertGregorian(FALSE)
    157 {
    158     setTimeInMillis(getNow(), status);
    159 }
    160 
    161 // -------------------------------------
    162 
    163 GregorianCalendar::GregorianCalendar(TimeZone* zone, UErrorCode& status)
    164 :   Calendar(zone, Locale::getDefault(), status),
    165 fGregorianCutover(kPapalCutover),
    166 fCutoverJulianDay(kCutoverJulianDay), fNormalizedGregorianCutover(fGregorianCutover), fGregorianCutoverYear(1582),
    167 fIsGregorian(TRUE), fInvertGregorian(FALSE)
    168 {
    169     setTimeInMillis(getNow(), status);
    170 }
    171 
    172 // -------------------------------------
    173 
    174 GregorianCalendar::GregorianCalendar(const TimeZone& zone, UErrorCode& status)
    175 :   Calendar(zone, Locale::getDefault(), status),
    176 fGregorianCutover(kPapalCutover),
    177 fCutoverJulianDay(kCutoverJulianDay), fNormalizedGregorianCutover(fGregorianCutover), fGregorianCutoverYear(1582),
    178 fIsGregorian(TRUE), fInvertGregorian(FALSE)
    179 {
    180     setTimeInMillis(getNow(), status);
    181 }
    182 
    183 // -------------------------------------
    184 
    185 GregorianCalendar::GregorianCalendar(const Locale& aLocale, UErrorCode& status)
    186 :   Calendar(TimeZone::createDefault(), aLocale, status),
    187 fGregorianCutover(kPapalCutover),
    188 fCutoverJulianDay(kCutoverJulianDay), fNormalizedGregorianCutover(fGregorianCutover), fGregorianCutoverYear(1582),
    189 fIsGregorian(TRUE), fInvertGregorian(FALSE)
    190 {
    191     setTimeInMillis(getNow(), status);
    192 }
    193 
    194 // -------------------------------------
    195 
    196 GregorianCalendar::GregorianCalendar(TimeZone* zone, const Locale& aLocale,
    197                                      UErrorCode& status)
    198                                      :   Calendar(zone, aLocale, status),
    199                                      fGregorianCutover(kPapalCutover),
    200                                      fCutoverJulianDay(kCutoverJulianDay), fNormalizedGregorianCutover(fGregorianCutover), fGregorianCutoverYear(1582),
    201                                      fIsGregorian(TRUE), fInvertGregorian(FALSE)
    202 {
    203     setTimeInMillis(getNow(), status);
    204 }
    205 
    206 // -------------------------------------
    207 
    208 GregorianCalendar::GregorianCalendar(const TimeZone& zone, const Locale& aLocale,
    209                                      UErrorCode& status)
    210                                      :   Calendar(zone, aLocale, status),
    211                                      fGregorianCutover(kPapalCutover),
    212                                      fCutoverJulianDay(kCutoverJulianDay), fNormalizedGregorianCutover(fGregorianCutover), fGregorianCutoverYear(1582),
    213                                      fIsGregorian(TRUE), fInvertGregorian(FALSE)
    214 {
    215     setTimeInMillis(getNow(), status);
    216 }
    217 
    218 // -------------------------------------
    219 
    220 GregorianCalendar::GregorianCalendar(int32_t year, int32_t month, int32_t date,
    221                                      UErrorCode& status)
    222                                      :   Calendar(TimeZone::createDefault(), Locale::getDefault(), status),
    223                                      fGregorianCutover(kPapalCutover),
    224                                      fCutoverJulianDay(kCutoverJulianDay), fNormalizedGregorianCutover(fGregorianCutover), fGregorianCutoverYear(1582),
    225                                      fIsGregorian(TRUE), fInvertGregorian(FALSE)
    226 {
    227     set(UCAL_ERA, AD);
    228     set(UCAL_YEAR, year);
    229     set(UCAL_MONTH, month);
    230     set(UCAL_DATE, date);
    231 }
    232 
    233 // -------------------------------------
    234 
    235 GregorianCalendar::GregorianCalendar(int32_t year, int32_t month, int32_t date,
    236                                      int32_t hour, int32_t minute, UErrorCode& status)
    237                                      :   Calendar(TimeZone::createDefault(), Locale::getDefault(), status),
    238                                      fGregorianCutover(kPapalCutover),
    239                                      fCutoverJulianDay(kCutoverJulianDay), fNormalizedGregorianCutover(fGregorianCutover), fGregorianCutoverYear(1582),
    240                                      fIsGregorian(TRUE), fInvertGregorian(FALSE)
    241 {
    242     set(UCAL_ERA, AD);
    243     set(UCAL_YEAR, year);
    244     set(UCAL_MONTH, month);
    245     set(UCAL_DATE, date);
    246     set(UCAL_HOUR_OF_DAY, hour);
    247     set(UCAL_MINUTE, minute);
    248 }
    249 
    250 // -------------------------------------
    251 
    252 GregorianCalendar::GregorianCalendar(int32_t year, int32_t month, int32_t date,
    253                                      int32_t hour, int32_t minute, int32_t second,
    254                                      UErrorCode& status)
    255                                      :   Calendar(TimeZone::createDefault(), Locale::getDefault(), status),
    256                                      fGregorianCutover(kPapalCutover),
    257                                      fCutoverJulianDay(kCutoverJulianDay), fNormalizedGregorianCutover(fGregorianCutover), fGregorianCutoverYear(1582),
    258                                      fIsGregorian(TRUE), fInvertGregorian(FALSE)
    259 {
    260     set(UCAL_ERA, AD);
    261     set(UCAL_YEAR, year);
    262     set(UCAL_MONTH, month);
    263     set(UCAL_DATE, date);
    264     set(UCAL_HOUR_OF_DAY, hour);
    265     set(UCAL_MINUTE, minute);
    266     set(UCAL_SECOND, second);
    267 }
    268 
    269 // -------------------------------------
    270 
    271 GregorianCalendar::~GregorianCalendar()
    272 {
    273 }
    274 
    275 // -------------------------------------
    276 
    277 GregorianCalendar::GregorianCalendar(const GregorianCalendar &source)
    278 :   Calendar(source),
    279 fGregorianCutover(source.fGregorianCutover),
    280 fCutoverJulianDay(source.fCutoverJulianDay), fNormalizedGregorianCutover(source.fNormalizedGregorianCutover), fGregorianCutoverYear(source.fGregorianCutoverYear),
    281 fIsGregorian(source.fIsGregorian), fInvertGregorian(source.fInvertGregorian)
    282 {
    283 }
    284 
    285 // -------------------------------------
    286 
    287 Calendar* GregorianCalendar::clone() const
    288 {
    289     return new GregorianCalendar(*this);
    290 }
    291 
    292 // -------------------------------------
    293 
    294 GregorianCalendar &
    295 GregorianCalendar::operator=(const GregorianCalendar &right)
    296 {
    297     if (this != &right)
    298     {
    299         Calendar::operator=(right);
    300         fGregorianCutover = right.fGregorianCutover;
    301         fNormalizedGregorianCutover = right.fNormalizedGregorianCutover;
    302         fGregorianCutoverYear = right.fGregorianCutoverYear;
    303         fCutoverJulianDay = right.fCutoverJulianDay;
    304     }
    305     return *this;
    306 }
    307 
    308 // -------------------------------------
    309 
    310 UBool GregorianCalendar::isEquivalentTo(const Calendar& other) const
    311 {
    312     // Calendar override.
    313     return Calendar::isEquivalentTo(other) &&
    314         fGregorianCutover == ((GregorianCalendar*)&other)->fGregorianCutover;
    315 }
    316 
    317 // -------------------------------------
    318 
    319 void
    320 GregorianCalendar::setGregorianChange(UDate date, UErrorCode& status)
    321 {
    322     if (U_FAILURE(status))
    323         return;
    324 
    325     fGregorianCutover = date;
    326 
    327     // Precompute two internal variables which we use to do the actual
    328     // cutover computations.  These are the normalized cutover, which is the
    329     // midnight at or before the cutover, and the cutover year.  The
    330     // normalized cutover is in pure date milliseconds; it contains no time
    331     // of day or timezone component, and it used to compare against other
    332     // pure date values.
    333     int32_t cutoverDay = (int32_t)ClockMath::floorDivide(fGregorianCutover, (double)kOneDay);
    334     fNormalizedGregorianCutover = cutoverDay * kOneDay;
    335 
    336     // Handle the rare case of numeric overflow.  If the user specifies a
    337     // change of UDate(Long.MIN_VALUE), in order to get a pure Gregorian
    338     // calendar, then the epoch day is -106751991168, which when multiplied
    339     // by ONE_DAY gives 9223372036794351616 -- the negative value is too
    340     // large for 64 bits, and overflows into a positive value.  We correct
    341     // this by using the next day, which for all intents is semantically
    342     // equivalent.
    343     if (cutoverDay < 0 && fNormalizedGregorianCutover > 0) {
    344         fNormalizedGregorianCutover = (cutoverDay + 1) * kOneDay;
    345     }
    346 
    347     // Normalize the year so BC values are represented as 0 and negative
    348     // values.
    349     GregorianCalendar *cal = new GregorianCalendar(getTimeZone(), status);
    350     /* test for NULL */
    351     if (cal == 0) {
    352         status = U_MEMORY_ALLOCATION_ERROR;
    353         return;
    354     }
    355     if(U_FAILURE(status))
    356         return;
    357     cal->setTime(date, status);
    358     fGregorianCutoverYear = cal->get(UCAL_YEAR, status);
    359     if (cal->get(UCAL_ERA, status) == BC)
    360         fGregorianCutoverYear = 1 - fGregorianCutoverYear;
    361     fCutoverJulianDay = cutoverDay;
    362     delete cal;
    363 }
    364 
    365 
    366 void GregorianCalendar::handleComputeFields(int32_t julianDay, UErrorCode& status) {
    367     int32_t eyear, month, dayOfMonth, dayOfYear;
    368 
    369 
    370     if(U_FAILURE(status)) {
    371         return;
    372     }
    373 
    374 #if defined (U_DEBUG_CAL)
    375     fprintf(stderr, "%s:%d: jd%d- (greg's %d)- [cut=%d]\n",
    376         __FILE__, __LINE__, julianDay, getGregorianDayOfYear(), fCutoverJulianDay);
    377 #endif
    378 
    379 
    380     if (julianDay >= fCutoverJulianDay) {
    381         month = getGregorianMonth();
    382         dayOfMonth = getGregorianDayOfMonth();
    383         dayOfYear = getGregorianDayOfYear();
    384         eyear = getGregorianYear();
    385     } else {
    386         // The Julian epoch day (not the same as Julian Day)
    387         // is zero on Saturday December 30, 0 (Gregorian).
    388         int32_t julianEpochDay = julianDay - (kJan1_1JulianDay - 2);
    389         eyear = (int32_t) ClockMath::floorDivide(4*julianEpochDay + 1464, 1461);
    390 
    391         // Compute the Julian calendar day number for January 1, eyear
    392         int32_t january1 = 365*(eyear-1) + ClockMath::floorDivide(eyear-1, (int32_t)4);
    393         dayOfYear = (julianEpochDay - january1); // 0-based
    394 
    395         // Julian leap years occurred historically every 4 years starting
    396         // with 8 AD.  Before 8 AD the spacing is irregular; every 3 years
    397         // from 45 BC to 9 BC, and then none until 8 AD.  However, we don't
    398         // implement this historical detail; instead, we implement the
    399         // computatinally cleaner proleptic calendar, which assumes
    400         // consistent 4-year cycles throughout time.
    401         UBool isLeap = ((eyear&0x3) == 0); // equiv. to (eyear%4 == 0)
    402 
    403         // Common Julian/Gregorian calculation
    404         int32_t correction = 0;
    405         int32_t march1 = isLeap ? 60 : 59; // zero-based DOY for March 1
    406         if (dayOfYear >= march1) {
    407             correction = isLeap ? 1 : 2;
    408         }
    409         month = (12 * (dayOfYear + correction) + 6) / 367; // zero-based month
    410         dayOfMonth = dayOfYear - (isLeap?kLeapNumDays[month]:kNumDays[month]) + 1; // one-based DOM
    411         ++dayOfYear;
    412 #if defined (U_DEBUG_CAL)
    413         //     fprintf(stderr, "%d - %d[%d] + 1\n", dayOfYear, isLeap?kLeapNumDays[month]:kNumDays[month], month );
    414         //           fprintf(stderr, "%s:%d:  greg's HCF %d -> %d/%d/%d not %d/%d/%d\n",
    415         //                   __FILE__, __LINE__,julianDay,
    416         //          eyear,month,dayOfMonth,
    417         //          getGregorianYear(), getGregorianMonth(), getGregorianDayOfMonth()  );
    418         fprintf(stderr, "%s:%d: doy %d (greg's %d)- [cut=%d]\n",
    419             __FILE__, __LINE__, dayOfYear, getGregorianDayOfYear(), fCutoverJulianDay);
    420 #endif
    421 
    422     }
    423 
    424     // [j81] if we are after the cutover in its year, shift the day of the year
    425     if((eyear == fGregorianCutoverYear) && (julianDay >= fCutoverJulianDay)) {
    426         //from handleComputeMonthStart
    427         int32_t gregShift = Grego::gregorianShift(eyear);
    428 #if defined (U_DEBUG_CAL)
    429         fprintf(stderr, "%s:%d:  gregorian shift %d :::  doy%d => %d [cut=%d]\n",
    430             __FILE__, __LINE__,gregShift, dayOfYear, dayOfYear+gregShift, fCutoverJulianDay);
    431 #endif
    432         dayOfYear += gregShift;
    433     }
    434 
    435     internalSet(UCAL_MONTH, month);
    436     internalSet(UCAL_DAY_OF_MONTH, dayOfMonth);
    437     internalSet(UCAL_DAY_OF_YEAR, dayOfYear);
    438     internalSet(UCAL_EXTENDED_YEAR, eyear);
    439     int32_t era = AD;
    440     if (eyear < 1) {
    441         era = BC;
    442         eyear = 1 - eyear;
    443     }
    444     internalSet(UCAL_ERA, era);
    445     internalSet(UCAL_YEAR, eyear);
    446 }
    447 
    448 
    449 // -------------------------------------
    450 
    451 UDate
    452 GregorianCalendar::getGregorianChange() const
    453 {
    454     return fGregorianCutover;
    455 }
    456 
    457 // -------------------------------------
    458 
    459 UBool
    460 GregorianCalendar::isLeapYear(int32_t year) const
    461 {
    462     // MSVC complains bitterly if we try to use Grego::isLeapYear here
    463     // NOTE: year&0x3 == year%4
    464     return (year >= fGregorianCutoverYear ?
    465         (((year&0x3) == 0) && ((year%100 != 0) || (year%400 == 0))) : // Gregorian
    466     ((year&0x3) == 0)); // Julian
    467 }
    468 
    469 // -------------------------------------
    470 
    471 int32_t GregorianCalendar::handleComputeJulianDay(UCalendarDateFields bestField)
    472 {
    473     fInvertGregorian = FALSE;
    474 
    475     int32_t jd = Calendar::handleComputeJulianDay(bestField);
    476 
    477     if((bestField == UCAL_WEEK_OF_YEAR) &&  // if we are doing WOY calculations, we are counting relative to Jan 1 *julian*
    478         (internalGet(UCAL_EXTENDED_YEAR)==fGregorianCutoverYear) &&
    479         jd >= fCutoverJulianDay) {
    480             fInvertGregorian = TRUE;  // So that the Julian Jan 1 will be used in handleComputeMonthStart
    481             return Calendar::handleComputeJulianDay(bestField);
    482         }
    483 
    484 
    485         // The following check handles portions of the cutover year BEFORE the
    486         // cutover itself happens.
    487         //if ((fIsGregorian==TRUE) != (jd >= fCutoverJulianDay)) {  /*  cutoverJulianDay)) { */
    488         if ((fIsGregorian==TRUE) != (jd >= fCutoverJulianDay)) {  /*  cutoverJulianDay)) { */
    489 #if defined (U_DEBUG_CAL)
    490             fprintf(stderr, "%s:%d: jd [invert] %d\n",
    491                 __FILE__, __LINE__, jd);
    492 #endif
    493             fInvertGregorian = TRUE;
    494             jd = Calendar::handleComputeJulianDay(bestField);
    495 #if defined (U_DEBUG_CAL)
    496             fprintf(stderr, "%s:%d:  fIsGregorian %s, fInvertGregorian %s - ",
    497                 __FILE__, __LINE__,fIsGregorian?"T":"F", fInvertGregorian?"T":"F");
    498             fprintf(stderr, " jd NOW %d\n",
    499                 jd);
    500 #endif
    501         } else {
    502 #if defined (U_DEBUG_CAL)
    503             fprintf(stderr, "%s:%d: jd [==] %d - %sfIsGregorian %sfInvertGregorian, %d\n",
    504                 __FILE__, __LINE__, jd, fIsGregorian?"T":"F", fInvertGregorian?"T":"F", bestField);
    505 #endif
    506         }
    507 
    508         if(fIsGregorian && (internalGet(UCAL_EXTENDED_YEAR) == fGregorianCutoverYear)) {
    509             int32_t gregShift = Grego::gregorianShift(internalGet(UCAL_EXTENDED_YEAR));
    510             if (bestField == UCAL_DAY_OF_YEAR) {
    511 #if defined (U_DEBUG_CAL)
    512                 fprintf(stderr, "%s:%d: [DOY%d] gregorian shift of JD %d += %d\n",
    513                     __FILE__, __LINE__, fFields[bestField],jd, gregShift);
    514 #endif
    515                 jd -= gregShift;
    516             } else if ( bestField == UCAL_WEEK_OF_MONTH ) {
    517                 int32_t weekShift = 14;
    518 #if defined (U_DEBUG_CAL)
    519                 fprintf(stderr, "%s:%d: [WOY/WOM] gregorian week shift of %d += %d\n",
    520                     __FILE__, __LINE__, jd, weekShift);
    521 #endif
    522                 jd += weekShift; // shift by weeks for week based fields.
    523             }
    524         }
    525 
    526         return jd;
    527 }
    528 
    529 int32_t GregorianCalendar::handleComputeMonthStart(int32_t eyear, int32_t month,
    530 
    531                                                    UBool /* useMonth */) const
    532 {
    533     GregorianCalendar *nonConstThis = (GregorianCalendar*)this; // cast away const
    534 
    535     // If the month is out of range, adjust it into range, and
    536     // modify the extended year value accordingly.
    537     if (month < 0 || month > 11) {
    538         eyear += ClockMath::floorDivide(month, 12, month);
    539     }
    540 
    541     UBool isLeap = eyear%4 == 0;
    542     int32_t y = eyear-1;
    543     int32_t julianDay = 365*y + ClockMath::floorDivide(y, 4) + (kJan1_1JulianDay - 3);
    544 
    545     nonConstThis->fIsGregorian = (eyear >= fGregorianCutoverYear);
    546 #if defined (U_DEBUG_CAL)
    547     fprintf(stderr, "%s:%d: (hcms%d/%d) fIsGregorian %s, fInvertGregorian %s\n",
    548         __FILE__, __LINE__, eyear,month, fIsGregorian?"T":"F", fInvertGregorian?"T":"F");
    549 #endif
    550     if (fInvertGregorian) {
    551         nonConstThis->fIsGregorian = !fIsGregorian;
    552     }
    553     if (fIsGregorian) {
    554         isLeap = isLeap && ((eyear%100 != 0) || (eyear%400 == 0));
    555         // Add 2 because Gregorian calendar starts 2 days after
    556         // Julian calendar
    557         int32_t gregShift = Grego::gregorianShift(eyear);
    558 #if defined (U_DEBUG_CAL)
    559         fprintf(stderr, "%s:%d: (hcms%d/%d) gregorian shift of %d += %d\n",
    560             __FILE__, __LINE__, eyear, month, julianDay, gregShift);
    561 #endif
    562         julianDay += gregShift;
    563     }
    564 
    565     // At this point julianDay indicates the day BEFORE the first
    566     // day of January 1, <eyear> of either the Julian or Gregorian
    567     // calendar.
    568 
    569     if (month != 0) {
    570         julianDay += isLeap?kLeapNumDays[month]:kNumDays[month];
    571     }
    572 
    573     return julianDay;
    574 }
    575 
    576 int32_t GregorianCalendar::handleGetMonthLength(int32_t extendedYear, int32_t month)  const
    577 {
    578     // If the month is out of range, adjust it into range, and
    579     // modify the extended year value accordingly.
    580     if (month < 0 || month > 11) {
    581         extendedYear += ClockMath::floorDivide(month, 12, month);
    582     }
    583 
    584     return isLeapYear(extendedYear) ? kLeapMonthLength[month] : kMonthLength[month];
    585 }
    586 
    587 int32_t GregorianCalendar::handleGetYearLength(int32_t eyear) const {
    588     return isLeapYear(eyear) ? 366 : 365;
    589 }
    590 
    591 
    592 int32_t
    593 GregorianCalendar::monthLength(int32_t month) const
    594 {
    595     int32_t year = internalGet(UCAL_EXTENDED_YEAR);
    596     return handleGetMonthLength(year, month);
    597 }
    598 
    599 // -------------------------------------
    600 
    601 int32_t
    602 GregorianCalendar::monthLength(int32_t month, int32_t year) const
    603 {
    604     return isLeapYear(year) ? kLeapMonthLength[month] : kMonthLength[month];
    605 }
    606 
    607 // -------------------------------------
    608 
    609 int32_t
    610 GregorianCalendar::yearLength(int32_t year) const
    611 {
    612     return isLeapYear(year) ? 366 : 365;
    613 }
    614 
    615 // -------------------------------------
    616 
    617 int32_t
    618 GregorianCalendar::yearLength() const
    619 {
    620     return isLeapYear(internalGet(UCAL_YEAR)) ? 366 : 365;
    621 }
    622 
    623 // -------------------------------------
    624 
    625 /**
    626 * After adjustments such as add(MONTH), add(YEAR), we don't want the
    627 * month to jump around.  E.g., we don't want Jan 31 + 1 month to go to Mar
    628 * 3, we want it to go to Feb 28.  Adjustments which might run into this
    629 * problem call this method to retain the proper month.
    630 */
    631 void
    632 GregorianCalendar::pinDayOfMonth()
    633 {
    634     int32_t monthLen = monthLength(internalGet(UCAL_MONTH));
    635     int32_t dom = internalGet(UCAL_DATE);
    636     if(dom > monthLen)
    637         set(UCAL_DATE, monthLen);
    638 }
    639 
    640 // -------------------------------------
    641 
    642 
    643 UBool
    644 GregorianCalendar::validateFields() const
    645 {
    646     for (int32_t field = 0; field < UCAL_FIELD_COUNT; field++) {
    647         // Ignore DATE and DAY_OF_YEAR which are handled below
    648         if (field != UCAL_DATE &&
    649             field != UCAL_DAY_OF_YEAR &&
    650             isSet((UCalendarDateFields)field) &&
    651             ! boundsCheck(internalGet((UCalendarDateFields)field), (UCalendarDateFields)field))
    652             return FALSE;
    653     }
    654 
    655     // Values differ in Least-Maximum and Maximum should be handled
    656     // specially.
    657     if (isSet(UCAL_DATE)) {
    658         int32_t date = internalGet(UCAL_DATE);
    659         if (date < getMinimum(UCAL_DATE) ||
    660             date > monthLength(internalGet(UCAL_MONTH))) {
    661                 return FALSE;
    662             }
    663     }
    664 
    665     if (isSet(UCAL_DAY_OF_YEAR)) {
    666         int32_t days = internalGet(UCAL_DAY_OF_YEAR);
    667         if (days < 1 || days > yearLength()) {
    668             return FALSE;
    669         }
    670     }
    671 
    672     // Handle DAY_OF_WEEK_IN_MONTH, which must not have the value zero.
    673     // We've checked against minimum and maximum above already.
    674     if (isSet(UCAL_DAY_OF_WEEK_IN_MONTH) &&
    675         0 == internalGet(UCAL_DAY_OF_WEEK_IN_MONTH)) {
    676             return FALSE;
    677         }
    678 
    679         return TRUE;
    680 }
    681 
    682 // -------------------------------------
    683 
    684 UBool
    685 GregorianCalendar::boundsCheck(int32_t value, UCalendarDateFields field) const
    686 {
    687     return value >= getMinimum(field) && value <= getMaximum(field);
    688 }
    689 
    690 // -------------------------------------
    691 
    692 UDate
    693 GregorianCalendar::getEpochDay(UErrorCode& status)
    694 {
    695     complete(status);
    696     // Divide by 1000 (convert to seconds) in order to prevent overflow when
    697     // dealing with UDate(Long.MIN_VALUE) and UDate(Long.MAX_VALUE).
    698     double wallSec = internalGetTime()/1000 + (internalGet(UCAL_ZONE_OFFSET) + internalGet(UCAL_DST_OFFSET))/1000;
    699 
    700     return ClockMath::floorDivide(wallSec, kOneDay/1000.0);
    701 }
    702 
    703 // -------------------------------------
    704 
    705 
    706 // -------------------------------------
    707 
    708 /**
    709 * Compute the julian day number of the day BEFORE the first day of
    710 * January 1, year 1 of the given calendar.  If julianDay == 0, it
    711 * specifies (Jan. 1, 1) - 1, in whatever calendar we are using (Julian
    712 * or Gregorian).
    713 */
    714 double GregorianCalendar::computeJulianDayOfYear(UBool isGregorian,
    715                                                  int32_t year, UBool& isLeap)
    716 {
    717     isLeap = year%4 == 0;
    718     int32_t y = year - 1;
    719     double julianDay = 365.0*y + ClockMath::floorDivide(y, 4) + (kJan1_1JulianDay - 3);
    720 
    721     if (isGregorian) {
    722         isLeap = isLeap && ((year%100 != 0) || (year%400 == 0));
    723         // Add 2 because Gregorian calendar starts 2 days after Julian calendar
    724         julianDay += Grego::gregorianShift(year);
    725     }
    726 
    727     return julianDay;
    728 }
    729 
    730 // /**
    731 //  * Compute the day of week, relative to the first day of week, from
    732 //  * 0..6, of the current DOW_LOCAL or DAY_OF_WEEK fields.  This is
    733 //  * equivalent to get(DOW_LOCAL) - 1.
    734 //  */
    735 // int32_t GregorianCalendar::computeRelativeDOW() const {
    736 //     int32_t relDow = 0;
    737 //     if (fStamp[UCAL_DOW_LOCAL] > fStamp[UCAL_DAY_OF_WEEK]) {
    738 //         relDow = internalGet(UCAL_DOW_LOCAL) - 1; // 1-based
    739 //     } else if (fStamp[UCAL_DAY_OF_WEEK] != kUnset) {
    740 //         relDow = internalGet(UCAL_DAY_OF_WEEK) - getFirstDayOfWeek();
    741 //         if (relDow < 0) relDow += 7;
    742 //     }
    743 //     return relDow;
    744 // }
    745 
    746 // /**
    747 //  * Compute the day of week, relative to the first day of week,
    748 //  * from 0..6 of the given julian day.
    749 //  */
    750 // int32_t GregorianCalendar::computeRelativeDOW(double julianDay) const {
    751 //   int32_t relDow = julianDayToDayOfWeek(julianDay) - getFirstDayOfWeek();
    752 //     if (relDow < 0) {
    753 //         relDow += 7;
    754 //     }
    755 //     return relDow;
    756 // }
    757 
    758 // /**
    759 //  * Compute the DOY using the WEEK_OF_YEAR field and the julian day
    760 //  * of the day BEFORE January 1 of a year (a return value from
    761 //  * computeJulianDayOfYear).
    762 //  */
    763 // int32_t GregorianCalendar::computeDOYfromWOY(double julianDayOfYear) const {
    764 //     // Compute DOY from day of week plus week of year
    765 
    766 //     // Find the day of the week for the first of this year.  This
    767 //     // is zero-based, with 0 being the locale-specific first day of
    768 //     // the week.  Add 1 to get first day of year.
    769 //     int32_t fdy = computeRelativeDOW(julianDayOfYear + 1);
    770 
    771 //     return
    772 //         // Compute doy of first (relative) DOW of WOY 1
    773 //         (((7 - fdy) < getMinimalDaysInFirstWeek())
    774 //          ? (8 - fdy) : (1 - fdy))
    775 
    776 //         // Adjust for the week number.
    777 //         + (7 * (internalGet(UCAL_WEEK_OF_YEAR) - 1))
    778 
    779 //         // Adjust for the DOW
    780 //         + computeRelativeDOW();
    781 // }
    782 
    783 // -------------------------------------
    784 
    785 double
    786 GregorianCalendar::millisToJulianDay(UDate millis)
    787 {
    788     return (double)kEpochStartAsJulianDay + ClockMath::floorDivide(millis, (double)kOneDay);
    789 }
    790 
    791 // -------------------------------------
    792 
    793 UDate
    794 GregorianCalendar::julianDayToMillis(double julian)
    795 {
    796     return (UDate) ((julian - kEpochStartAsJulianDay) * (double) kOneDay);
    797 }
    798 
    799 // -------------------------------------
    800 
    801 int32_t
    802 GregorianCalendar::aggregateStamp(int32_t stamp_a, int32_t stamp_b)
    803 {
    804     return (((stamp_a != kUnset && stamp_b != kUnset)
    805         ? uprv_max(stamp_a, stamp_b)
    806         : (int32_t)kUnset));
    807 }
    808 
    809 // -------------------------------------
    810 
    811 /**
    812 * Roll a field by a signed amount.
    813 * Note: This will be made public later. [LIU]
    814 */
    815 
    816 void
    817 GregorianCalendar::roll(EDateFields field, int32_t amount, UErrorCode& status) {
    818     roll((UCalendarDateFields) field, amount, status);
    819 }
    820 
    821 void
    822 GregorianCalendar::roll(UCalendarDateFields field, int32_t amount, UErrorCode& status)
    823 {
    824     if((amount == 0) || U_FAILURE(status)) {
    825         return;
    826     }
    827 
    828     // J81 processing. (gregorian cutover)
    829     UBool inCutoverMonth = FALSE;
    830     int32_t cMonthLen=0; // 'c' for cutover; in days
    831     int32_t cDayOfMonth=0; // no discontinuity: [0, cMonthLen)
    832     double cMonthStart=0.0; // in ms
    833 
    834     // Common code - see if we're in the cutover month of the cutover year
    835     if(get(UCAL_EXTENDED_YEAR, status) == fGregorianCutoverYear) {
    836         switch (field) {
    837         case UCAL_DAY_OF_MONTH:
    838         case UCAL_WEEK_OF_MONTH:
    839             {
    840                 int32_t max = monthLength(internalGet(UCAL_MONTH));
    841                 UDate t = internalGetTime();
    842                 // We subtract 1 from the DAY_OF_MONTH to make it zero-based, and an
    843                 // additional 10 if we are after the cutover. Thus the monthStart
    844                 // value will be correct iff we actually are in the cutover month.
    845                 cDayOfMonth = internalGet(UCAL_DAY_OF_MONTH) - ((t >= fGregorianCutover) ? 10 : 0);
    846                 cMonthStart = t - ((cDayOfMonth - 1) * kOneDay);
    847                 // A month containing the cutover is 10 days shorter.
    848                 if ((cMonthStart < fGregorianCutover) &&
    849                     (cMonthStart + (cMonthLen=(max-10))*kOneDay >= fGregorianCutover)) {
    850                         inCutoverMonth = TRUE;
    851                     }
    852             }
    853         default:
    854             ;
    855         }
    856     }
    857 
    858     switch (field) {
    859     case UCAL_WEEK_OF_YEAR: {
    860         // Unlike WEEK_OF_MONTH, WEEK_OF_YEAR never shifts the day of the
    861         // week.  Also, rolling the week of the year can have seemingly
    862         // strange effects simply because the year of the week of year
    863         // may be different from the calendar year.  For example, the
    864         // date Dec 28, 1997 is the first day of week 1 of 1998 (if
    865         // weeks start on Sunday and the minimal days in first week is
    866         // <= 3).
    867         int32_t woy = get(UCAL_WEEK_OF_YEAR, status);
    868         // Get the ISO year, which matches the week of year.  This
    869         // may be one year before or after the calendar year.
    870         int32_t isoYear = get(UCAL_YEAR_WOY, status);
    871         int32_t isoDoy = internalGet(UCAL_DAY_OF_YEAR);
    872         if (internalGet(UCAL_MONTH) == UCAL_JANUARY) {
    873             if (woy >= 52) {
    874                 isoDoy += handleGetYearLength(isoYear);
    875             }
    876         } else {
    877             if (woy == 1) {
    878                 isoDoy -= handleGetYearLength(isoYear - 1);
    879             }
    880         }
    881         woy += amount;
    882         // Do fast checks to avoid unnecessary computation:
    883         if (woy < 1 || woy > 52) {
    884             // Determine the last week of the ISO year.
    885             // We do this using the standard formula we use
    886             // everywhere in this file.  If we can see that the
    887             // days at the end of the year are going to fall into
    888             // week 1 of the next year, we drop the last week by
    889             // subtracting 7 from the last day of the year.
    890             int32_t lastDoy = handleGetYearLength(isoYear);
    891             int32_t lastRelDow = (lastDoy - isoDoy + internalGet(UCAL_DAY_OF_WEEK) -
    892                 getFirstDayOfWeek()) % 7;
    893             if (lastRelDow < 0) lastRelDow += 7;
    894             if ((6 - lastRelDow) >= getMinimalDaysInFirstWeek()) lastDoy -= 7;
    895             int32_t lastWoy = weekNumber(lastDoy, lastRelDow + 1);
    896             woy = ((woy + lastWoy - 1) % lastWoy) + 1;
    897         }
    898         set(UCAL_WEEK_OF_YEAR, woy);
    899         set(UCAL_YEAR_WOY,isoYear);
    900         return;
    901                             }
    902 
    903     case UCAL_DAY_OF_MONTH:
    904         if( !inCutoverMonth ) {
    905             Calendar::roll(field, amount, status);
    906             return;
    907         } else {
    908             // [j81] 1582 special case for DOM
    909             // The default computation works except when the current month
    910             // contains the Gregorian cutover.  We handle this special case
    911             // here.  [j81 - aliu]
    912             double monthLen = cMonthLen * kOneDay;
    913             double msIntoMonth = uprv_fmod(internalGetTime() - cMonthStart +
    914                 amount * kOneDay, monthLen);
    915             if (msIntoMonth < 0) {
    916                 msIntoMonth += monthLen;
    917             }
    918 #if defined (U_DEBUG_CAL)
    919             fprintf(stderr, "%s:%d: roll DOM %d  -> %.0lf ms  \n",
    920                 __FILE__, __LINE__,amount, cMonthLen, cMonthStart+msIntoMonth);
    921 #endif
    922             setTimeInMillis(cMonthStart + msIntoMonth, status);
    923             return;
    924         }
    925 
    926     case UCAL_WEEK_OF_MONTH:
    927         if( !inCutoverMonth ) {
    928             Calendar::roll(field, amount, status);
    929             return;
    930         } else {
    931 #if defined (U_DEBUG_CAL)
    932             fprintf(stderr, "%s:%d: roll WOM %d ??????????????????? \n",
    933                 __FILE__, __LINE__,amount);
    934 #endif
    935             // NOTE: following copied from  the old
    936             //     GregorianCalendar::roll( WEEK_OF_MONTH )  code
    937 
    938             // This is tricky, because during the roll we may have to shift
    939             // to a different day of the week.  For example:
    940 
    941             //    s  m  t  w  r  f  s
    942             //          1  2  3  4  5
    943             //    6  7  8  9 10 11 12
    944 
    945             // When rolling from the 6th or 7th back one week, we go to the
    946             // 1st (assuming that the first partial week counts).  The same
    947             // thing happens at the end of the month.
    948 
    949             // The other tricky thing is that we have to figure out whether
    950             // the first partial week actually counts or not, based on the
    951             // minimal first days in the week.  And we have to use the
    952             // correct first day of the week to delineate the week
    953             // boundaries.
    954 
    955             // Here's our algorithm.  First, we find the real boundaries of
    956             // the month.  Then we discard the first partial week if it
    957             // doesn't count in this locale.  Then we fill in the ends with
    958             // phantom days, so that the first partial week and the last
    959             // partial week are full weeks.  We then have a nice square
    960             // block of weeks.  We do the usual rolling within this block,
    961             // as is done elsewhere in this method.  If we wind up on one of
    962             // the phantom days that we added, we recognize this and pin to
    963             // the first or the last day of the month.  Easy, eh?
    964 
    965             // Another wrinkle: To fix jitterbug 81, we have to make all this
    966             // work in the oddball month containing the Gregorian cutover.
    967             // This month is 10 days shorter than usual, and also contains
    968             // a discontinuity in the days; e.g., the default cutover month
    969             // is Oct 1582, and goes from day of month 4 to day of month 15.
    970 
    971             // Normalize the DAY_OF_WEEK so that 0 is the first day of the week
    972             // in this locale.  We have dow in 0..6.
    973             int32_t dow = internalGet(UCAL_DAY_OF_WEEK) - getFirstDayOfWeek();
    974             if (dow < 0)
    975                 dow += 7;
    976 
    977             // Find the day of month, compensating for cutover discontinuity.
    978             int32_t dom = cDayOfMonth;
    979 
    980             // Find the day of the week (normalized for locale) for the first
    981             // of the month.
    982             int32_t fdm = (dow - dom + 1) % 7;
    983             if (fdm < 0)
    984                 fdm += 7;
    985 
    986             // Get the first day of the first full week of the month,
    987             // including phantom days, if any.  Figure out if the first week
    988             // counts or not; if it counts, then fill in phantom days.  If
    989             // not, advance to the first real full week (skip the partial week).
    990             int32_t start;
    991             if ((7 - fdm) < getMinimalDaysInFirstWeek())
    992                 start = 8 - fdm; // Skip the first partial week
    993             else
    994                 start = 1 - fdm; // This may be zero or negative
    995 
    996             // Get the day of the week (normalized for locale) for the last
    997             // day of the month.
    998             int32_t monthLen = cMonthLen;
    999             int32_t ldm = (monthLen - dom + dow) % 7;
   1000             // We know monthLen >= DAY_OF_MONTH so we skip the += 7 step here.
   1001 
   1002             // Get the limit day for the blocked-off rectangular month; that
   1003             // is, the day which is one past the last day of the month,
   1004             // after the month has already been filled in with phantom days
   1005             // to fill out the last week.  This day has a normalized DOW of 0.
   1006             int32_t limit = monthLen + 7 - ldm;
   1007 
   1008             // Now roll between start and (limit - 1).
   1009             int32_t gap = limit - start;
   1010             int32_t newDom = (dom + amount*7 - start) % gap;
   1011             if (newDom < 0)
   1012                 newDom += gap;
   1013             newDom += start;
   1014 
   1015             // Finally, pin to the real start and end of the month.
   1016             if (newDom < 1)
   1017                 newDom = 1;
   1018             if (newDom > monthLen)
   1019                 newDom = monthLen;
   1020 
   1021             // Set the DAY_OF_MONTH.  We rely on the fact that this field
   1022             // takes precedence over everything else (since all other fields
   1023             // are also set at this point).  If this fact changes (if the
   1024             // disambiguation algorithm changes) then we will have to unset
   1025             // the appropriate fields here so that DAY_OF_MONTH is attended
   1026             // to.
   1027 
   1028             // If we are in the cutover month, manipulate ms directly.  Don't do
   1029             // this in general because it doesn't work across DST boundaries
   1030             // (details, details).  This takes care of the discontinuity.
   1031             setTimeInMillis(cMonthStart + (newDom-1)*kOneDay, status);
   1032             return;
   1033         }
   1034 
   1035     default:
   1036         Calendar::roll(field, amount, status);
   1037         return;
   1038     }
   1039 }
   1040 
   1041 // -------------------------------------
   1042 
   1043 
   1044 /**
   1045 * Return the minimum value that this field could have, given the current date.
   1046 * For the Gregorian calendar, this is the same as getMinimum() and getGreatestMinimum().
   1047 * @param field    the time field.
   1048 * @return         the minimum value that this field could have, given the current date.
   1049 * @deprecated ICU 2.6. Use getActualMinimum(UCalendarDateFields field) instead.
   1050 */
   1051 int32_t GregorianCalendar::getActualMinimum(EDateFields field) const
   1052 {
   1053     return getMinimum((UCalendarDateFields)field);
   1054 }
   1055 
   1056 int32_t GregorianCalendar::getActualMinimum(EDateFields field, UErrorCode& /* status */) const
   1057 {
   1058     return getMinimum((UCalendarDateFields)field);
   1059 }
   1060 
   1061 /**
   1062 * Return the minimum value that this field could have, given the current date.
   1063 * For the Gregorian calendar, this is the same as getMinimum() and getGreatestMinimum().
   1064 * @param field    the time field.
   1065 * @return         the minimum value that this field could have, given the current date.
   1066 * @draft ICU 2.6.
   1067 */
   1068 int32_t GregorianCalendar::getActualMinimum(UCalendarDateFields field, UErrorCode& /* status */) const
   1069 {
   1070     return getMinimum(field);
   1071 }
   1072 
   1073 
   1074 // ------------------------------------
   1075 
   1076 /**
   1077 * Old year limits were least max 292269054, max 292278994.
   1078 */
   1079 
   1080 /**
   1081 * @stable ICU 2.0
   1082 */
   1083 int32_t GregorianCalendar::handleGetLimit(UCalendarDateFields field, ELimitType limitType) const {
   1084     return kGregorianCalendarLimits[field][limitType];
   1085 }
   1086 
   1087 /**
   1088 * Return the maximum value that this field could have, given the current date.
   1089 * For example, with the date "Feb 3, 1997" and the DAY_OF_MONTH field, the actual
   1090 * maximum would be 28; for "Feb 3, 1996" it s 29.  Similarly for a Hebrew calendar,
   1091 * for some years the actual maximum for MONTH is 12, and for others 13.
   1092 * @stable ICU 2.0
   1093 */
   1094 int32_t GregorianCalendar::getActualMaximum(UCalendarDateFields field, UErrorCode& status) const
   1095 {
   1096     /* It is a known limitation that the code here (and in getActualMinimum)
   1097     * won't behave properly at the extreme limits of GregorianCalendar's
   1098     * representable range (except for the code that handles the YEAR
   1099     * field).  That's because the ends of the representable range are at
   1100     * odd spots in the year.  For calendars with the default Gregorian
   1101     * cutover, these limits are Sun Dec 02 16:47:04 GMT 292269055 BC to Sun
   1102     * Aug 17 07:12:55 GMT 292278994 AD, somewhat different for non-GMT
   1103     * zones.  As a result, if the calendar is set to Aug 1 292278994 AD,
   1104     * the actual maximum of DAY_OF_MONTH is 17, not 30.  If the date is Mar
   1105     * 31 in that year, the actual maximum month might be Jul, whereas is
   1106     * the date is Mar 15, the actual maximum might be Aug -- depending on
   1107     * the precise semantics that are desired.  Similar considerations
   1108     * affect all fields.  Nonetheless, this effect is sufficiently arcane
   1109     * that we permit it, rather than complicating the code to handle such
   1110     * intricacies. - liu 8/20/98
   1111 
   1112     * UPDATE: No longer true, since we have pulled in the limit values on
   1113     * the year. - Liu 11/6/00 */
   1114 
   1115     switch (field) {
   1116 
   1117     case UCAL_YEAR:
   1118         /* The year computation is no different, in principle, from the
   1119         * others, however, the range of possible maxima is large.  In
   1120         * addition, the way we know we've exceeded the range is different.
   1121         * For these reasons, we use the special case code below to handle
   1122         * this field.
   1123         *
   1124         * The actual maxima for YEAR depend on the type of calendar:
   1125         *
   1126         *     Gregorian = May 17, 292275056 BC - Aug 17, 292278994 AD
   1127         *     Julian    = Dec  2, 292269055 BC - Jan  3, 292272993 AD
   1128         *     Hybrid    = Dec  2, 292269055 BC - Aug 17, 292278994 AD
   1129         *
   1130         * We know we've exceeded the maximum when either the month, date,
   1131         * time, or era changes in response to setting the year.  We don't
   1132         * check for month, date, and time here because the year and era are
   1133         * sufficient to detect an invalid year setting.  NOTE: If code is
   1134         * added to check the month and date in the future for some reason,
   1135         * Feb 29 must be allowed to shift to Mar 1 when setting the year.
   1136         */
   1137         {
   1138             if(U_FAILURE(status)) return 0;
   1139             Calendar *cal = clone();
   1140             if(!cal) {
   1141                 status = U_MEMORY_ALLOCATION_ERROR;
   1142                 return 0;
   1143             }
   1144 
   1145             cal->setLenient(TRUE);
   1146 
   1147             int32_t era = cal->get(UCAL_ERA, status);
   1148             UDate d = cal->getTime(status);
   1149 
   1150             /* Perform a binary search, with the invariant that lowGood is a
   1151             * valid year, and highBad is an out of range year.
   1152             */
   1153             int32_t lowGood = kGregorianCalendarLimits[UCAL_YEAR][1];
   1154             int32_t highBad = kGregorianCalendarLimits[UCAL_YEAR][2]+1;
   1155             while ((lowGood + 1) < highBad) {
   1156                 int32_t y = (lowGood + highBad) / 2;
   1157                 cal->set(UCAL_YEAR, y);
   1158                 if (cal->get(UCAL_YEAR, status) == y && cal->get(UCAL_ERA, status) == era) {
   1159                     lowGood = y;
   1160                 } else {
   1161                     highBad = y;
   1162                     cal->setTime(d, status); // Restore original fields
   1163                 }
   1164             }
   1165 
   1166             delete cal;
   1167             return lowGood;
   1168         }
   1169 
   1170     default:
   1171         return Calendar::getActualMaximum(field,status);
   1172     }
   1173 }
   1174 
   1175 
   1176 int32_t GregorianCalendar::handleGetExtendedYear() {
   1177     // the year to return
   1178     int32_t year = kEpochYear;
   1179 
   1180     // year field to use
   1181     int32_t yearField = UCAL_EXTENDED_YEAR;
   1182 
   1183     // There are three separate fields which could be used to
   1184     // derive the proper year.  Use the one most recently set.
   1185     if (fStamp[yearField] < fStamp[UCAL_YEAR])
   1186         yearField = UCAL_YEAR;
   1187     if (fStamp[yearField] < fStamp[UCAL_YEAR_WOY])
   1188         yearField = UCAL_YEAR_WOY;
   1189 
   1190     // based on the "best" year field, get the year
   1191     switch(yearField) {
   1192     case UCAL_EXTENDED_YEAR:
   1193         year = internalGet(UCAL_EXTENDED_YEAR, kEpochYear);
   1194         break;
   1195 
   1196     case UCAL_YEAR:
   1197         {
   1198             // The year defaults to the epoch start, the era to AD
   1199             int32_t era = internalGet(UCAL_ERA, AD);
   1200             if (era == BC) {
   1201                 year = 1 - internalGet(UCAL_YEAR, 1); // Convert to extended year
   1202             } else {
   1203                 year = internalGet(UCAL_YEAR, kEpochYear);
   1204             }
   1205         }
   1206         break;
   1207 
   1208     case UCAL_YEAR_WOY:
   1209         year = handleGetExtendedYearFromWeekFields(internalGet(UCAL_YEAR_WOY), internalGet(UCAL_WEEK_OF_YEAR));
   1210 #if defined (U_DEBUG_CAL)
   1211         //    if(internalGet(UCAL_YEAR_WOY) != year) {
   1212         fprintf(stderr, "%s:%d: hGEYFWF[%d,%d] ->  %d\n",
   1213             __FILE__, __LINE__,internalGet(UCAL_YEAR_WOY),internalGet(UCAL_WEEK_OF_YEAR),year);
   1214         //}
   1215 #endif
   1216         break;
   1217 
   1218     default:
   1219         year = kEpochYear;
   1220     }
   1221     return year;
   1222 }
   1223 
   1224 int32_t GregorianCalendar::handleGetExtendedYearFromWeekFields(int32_t yearWoy, int32_t woy)
   1225 {
   1226     // convert year to extended form
   1227     int32_t era = internalGet(UCAL_ERA, AD);
   1228     if(era == BC) {
   1229         yearWoy = 1 - yearWoy;
   1230     }
   1231     return Calendar::handleGetExtendedYearFromWeekFields(yearWoy, woy);
   1232 }
   1233 
   1234 
   1235 // -------------------------------------
   1236 
   1237 UBool
   1238 GregorianCalendar::inDaylightTime(UErrorCode& status) const
   1239 {
   1240     if (U_FAILURE(status) || !getTimeZone().useDaylightTime())
   1241         return FALSE;
   1242 
   1243     // Force an update of the state of the Calendar.
   1244     ((GregorianCalendar*)this)->complete(status); // cast away const
   1245 
   1246     return (UBool)(U_SUCCESS(status) ? (internalGet(UCAL_DST_OFFSET) != 0) : FALSE);
   1247 }
   1248 
   1249 // -------------------------------------
   1250 
   1251 /**
   1252 * Return the ERA.  We need a special method for this because the
   1253 * default ERA is AD, but a zero (unset) ERA is BC.
   1254 */
   1255 int32_t
   1256 GregorianCalendar::internalGetEra() const {
   1257     return isSet(UCAL_ERA) ? internalGet(UCAL_ERA) : (int32_t)AD;
   1258 }
   1259 
   1260 const char *
   1261 GregorianCalendar::getType() const {
   1262     //static const char kGregorianType = "gregorian";
   1263 
   1264     return "gregorian";
   1265 }
   1266 
   1267 const UDate     GregorianCalendar::fgSystemDefaultCentury        = DBL_MIN;
   1268 const int32_t   GregorianCalendar::fgSystemDefaultCenturyYear    = -1;
   1269 
   1270 UDate           GregorianCalendar::fgSystemDefaultCenturyStart       = DBL_MIN;
   1271 int32_t         GregorianCalendar::fgSystemDefaultCenturyStartYear   = -1;
   1272 
   1273 
   1274 UBool GregorianCalendar::haveDefaultCentury() const
   1275 {
   1276     return TRUE;
   1277 }
   1278 
   1279 UDate GregorianCalendar::defaultCenturyStart() const
   1280 {
   1281     return internalGetDefaultCenturyStart();
   1282 }
   1283 
   1284 int32_t GregorianCalendar::defaultCenturyStartYear() const
   1285 {
   1286     return internalGetDefaultCenturyStartYear();
   1287 }
   1288 
   1289 UDate
   1290 GregorianCalendar::internalGetDefaultCenturyStart() const
   1291 {
   1292     // lazy-evaluate systemDefaultCenturyStart
   1293     UBool needsUpdate;
   1294     UMTX_CHECK(NULL, (fgSystemDefaultCenturyStart == fgSystemDefaultCentury), needsUpdate);
   1295 
   1296     if (needsUpdate) {
   1297         initializeSystemDefaultCentury();
   1298     }
   1299 
   1300     // use defaultCenturyStart unless it's the flag value;
   1301     // then use systemDefaultCenturyStart
   1302 
   1303     return fgSystemDefaultCenturyStart;
   1304 }
   1305 
   1306 int32_t
   1307 GregorianCalendar::internalGetDefaultCenturyStartYear() const
   1308 {
   1309     // lazy-evaluate systemDefaultCenturyStartYear
   1310     UBool needsUpdate;
   1311     UMTX_CHECK(NULL, (fgSystemDefaultCenturyStart == fgSystemDefaultCentury), needsUpdate);
   1312 
   1313     if (needsUpdate) {
   1314         initializeSystemDefaultCentury();
   1315     }
   1316 
   1317     // use defaultCenturyStart unless it's the flag value;
   1318     // then use systemDefaultCenturyStartYear
   1319 
   1320     return fgSystemDefaultCenturyStartYear;
   1321 }
   1322 
   1323 void
   1324 GregorianCalendar::initializeSystemDefaultCentury()
   1325 {
   1326     // initialize systemDefaultCentury and systemDefaultCenturyYear based
   1327     // on the current time.  They'll be set to 80 years before
   1328     // the current time.
   1329     UErrorCode status = U_ZERO_ERROR;
   1330     Calendar *calendar = new GregorianCalendar(status);
   1331     if (calendar != NULL && U_SUCCESS(status))
   1332     {
   1333         calendar->setTime(Calendar::getNow(), status);
   1334         calendar->add(UCAL_YEAR, -80, status);
   1335 
   1336         UDate    newStart =  calendar->getTime(status);
   1337         int32_t  newYear  =  calendar->get(UCAL_YEAR, status);
   1338         umtx_lock(NULL);
   1339         if (fgSystemDefaultCenturyStart == fgSystemDefaultCentury)
   1340         {
   1341             fgSystemDefaultCenturyStartYear = newYear;
   1342             fgSystemDefaultCenturyStart = newStart;
   1343         }
   1344         umtx_unlock(NULL);
   1345         delete calendar;
   1346     }
   1347     // We have no recourse upon failure unless we want to propagate the failure
   1348     // out.
   1349 }
   1350 
   1351 
   1352 U_NAMESPACE_END
   1353 
   1354 #endif /* #if !UCONFIG_NO_FORMATTING */
   1355 
   1356 //eof
   1357