Check in the pristine copy of ICU 4.6...

icu46/source/i18n/gregocal.cpp

+/*
+*******************************************************************************
+* Copyright (C) 1997-2010, International Business Machines Corporation and    *
+* others. All Rights Reserved.                                                *
+*******************************************************************************
+*
+* File GREGOCAL.CPP
+*
+* Modification History:
+*
+*   Date        Name        Description
+*   02/05/97    clhuang     Creation.
+*   03/28/97    aliu        Made highly questionable fix to computeFields to
+*                           handle DST correctly.
+*   04/22/97    aliu        Cleaned up code drastically.  Added monthLength().
+*                           Finished unimplemented parts of computeTime() for
+*                           week-based date determination.  Removed quetionable
+*                           fix and wrote correct fix for computeFields() and
+*                           daylight time handling.  Rewrote inDaylightTime()
+*                           and computeFields() to handle sensitive Daylight to
+*                           Standard time transitions correctly.
+*   05/08/97    aliu        Added code review changes.  Fixed isLeapYear() to
+*                           not cutover.
+*   08/12/97    aliu        Added equivalentTo.  Misc other fixes.  Updated
+*                           add() from Java source.
+*    07/28/98    stephen        Sync up with JDK 1.2
+*    09/14/98    stephen        Changed type of kOneDay, kOneWeek to double.
+*                            Fixed bug in roll() 
+*   10/15/99    aliu        Fixed j31, incorrect WEEK_OF_YEAR computation.
+*   10/15/99    aliu        Fixed j32, cannot set date to Feb 29 2000 AD.
+*                           {JDK bug 4210209 4209272}
+*   11/15/99    weiv        Added YEAR_WOY and DOW_LOCAL computation
+*                           to timeToFields method, updated kMinValues, kMaxValues & kLeastMaxValues
+*   12/09/99    aliu        Fixed j81, calculation errors and roll bugs
+*                           in year of cutover.
+*   01/24/2000  aliu        Revised computeJulianDay for YEAR YEAR_WOY WOY.
+********************************************************************************
+*/
+
+#include "unicode/utypes.h"
+#include <float.h>
+
+#if !UCONFIG_NO_FORMATTING
+
+#include "unicode/gregocal.h"
+#include "gregoimp.h"
+#include "umutex.h"
+#include "uassert.h"
+
+// *****************************************************************************
+// class GregorianCalendar
+// *****************************************************************************
+
+/**
+* Note that the Julian date used here is not a true Julian date, since
+* it is measured from midnight, not noon.  This value is the Julian
+* day number of January 1, 1970 (Gregorian calendar) at noon UTC. [LIU]
+*/
+
+static const int16_t kNumDays[]
+= {0,31,59,90,120,151,181,212,243,273,304,334}; // 0-based, for day-in-year
+static const int16_t kLeapNumDays[]
+= {0,31,60,91,121,152,182,213,244,274,305,335}; // 0-based, for day-in-year
+static const int8_t kMonthLength[]
+= {31,28,31,30,31,30,31,31,30,31,30,31}; // 0-based
+static const int8_t kLeapMonthLength[]
+= {31,29,31,30,31,30,31,31,30,31,30,31}; // 0-based
+
+// setTimeInMillis() limits the Julian day range to +/-7F000000.
+// This would seem to limit the year range to:
+//  ms=+183882168921600000  jd=7f000000  December 20, 5828963 AD
+//  ms=-184303902528000000  jd=81000000  September 20, 5838270 BC
+// HOWEVER, CalendarRegressionTest/Test4167060 shows that the actual
+// range limit on the year field is smaller (~ +/-140000). [alan 3.0]
+
+static const int32_t kGregorianCalendarLimits[UCAL_FIELD_COUNT][4] = {
+    // Minimum  Greatest    Least  Maximum
+    //           Minimum  Maximum
+    {        0,        0,        1,        1}, // ERA
+    {        1,        1,   140742,   144683}, // YEAR
+    {        0,        0,       11,       11}, // MONTH
+    {        1,        1,       52,       53}, // WEEK_OF_YEAR
+    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // WEEK_OF_MONTH
+    {        1,        1,       28,       31}, // DAY_OF_MONTH
+    {        1,        1,      365,      366}, // DAY_OF_YEAR
+    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // DAY_OF_WEEK
+    {       -1,       -1,        4,        5}, // DAY_OF_WEEK_IN_MONTH
+    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // AM_PM
+    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // HOUR
+    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // HOUR_OF_DAY
+    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // MINUTE
+    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // SECOND
+    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // MILLISECOND
+    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // ZONE_OFFSET
+    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // DST_OFFSET
+    {  -140742,  -140742,   140742,   144683}, // YEAR_WOY
+    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // DOW_LOCAL
+    {  -140742,  -140742,   140742,   144683}, // EXTENDED_YEAR
+    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // JULIAN_DAY
+    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // MILLISECONDS_IN_DAY
+    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // IS_LEAP_MONTH
+};
+
+/*
+* <pre>
+*                            Greatest       Least 
+* Field name        Minimum   Minimum     Maximum     Maximum
+* ----------        -------   -------     -------     -------
+* ERA                     0         0           1           1
+* YEAR                    1         1      140742      144683
+* MONTH                   0         0          11          11
+* WEEK_OF_YEAR            1         1          52          53
+* WEEK_OF_MONTH           0         0           4           6
+* DAY_OF_MONTH            1         1          28          31
+* DAY_OF_YEAR             1         1         365         366
+* DAY_OF_WEEK             1         1           7           7
+* DAY_OF_WEEK_IN_MONTH   -1        -1           4           5
+* AM_PM                   0         0           1           1
+* HOUR                    0         0          11          11
+* HOUR_OF_DAY             0         0          23          23
+* MINUTE                  0         0          59          59
+* SECOND                  0         0          59          59
+* MILLISECOND             0         0         999         999
+* ZONE_OFFSET           -12*      -12*         12*         12*
+* DST_OFFSET              0         0           1*          1*
+* YEAR_WOY                1         1      140742      144683
+* DOW_LOCAL               1         1           7           7
+* </pre>
+* (*) In units of one-hour
+*/
+
+#if defined( U_DEBUG_CALSVC ) || defined (U_DEBUG_CAL)
+#include <stdio.h>
+#endif
+
+U_NAMESPACE_BEGIN
+
+UOBJECT_DEFINE_RTTI_IMPLEMENTATION(GregorianCalendar)
+
+// 00:00:00 UTC, October 15, 1582, expressed in ms from the epoch.
+// Note that only Italy and other Catholic countries actually
+// observed this cutover.  Most other countries followed in
+// the next few centuries, some as late as 1928. [LIU]
+// in Java, -12219292800000L
+//const UDate GregorianCalendar::kPapalCutover = -12219292800000L;
+static const uint32_t kCutoverJulianDay = 2299161;
+static const UDate kPapalCutover = (2299161.0 - kEpochStartAsJulianDay) * U_MILLIS_PER_DAY;
+//static const UDate kPapalCutoverJulian = (2299161.0 - kEpochStartAsJulianDay);
+
+// -------------------------------------
+
+GregorianCalendar::GregorianCalendar(UErrorCode& status)
+:   Calendar(status),
+fGregorianCutover(kPapalCutover),
+fCutoverJulianDay(kCutoverJulianDay), fNormalizedGregorianCutover(fGregorianCutover), fGregorianCutoverYear(1582),
+fIsGregorian(TRUE), fInvertGregorian(FALSE)
+{
+    setTimeInMillis(getNow(), status);
+}
+
+// -------------------------------------
+
+GregorianCalendar::GregorianCalendar(TimeZone* zone, UErrorCode& status)
+:   Calendar(zone, Locale::getDefault(), status),
+fGregorianCutover(kPapalCutover),
+fCutoverJulianDay(kCutoverJulianDay), fNormalizedGregorianCutover(fGregorianCutover), fGregorianCutoverYear(1582),
+fIsGregorian(TRUE), fInvertGregorian(FALSE)
+{
+    setTimeInMillis(getNow(), status);
+}
+
+// -------------------------------------
+
+GregorianCalendar::GregorianCalendar(const TimeZone& zone, UErrorCode& status)
+:   Calendar(zone, Locale::getDefault(), status),
+fGregorianCutover(kPapalCutover),
+fCutoverJulianDay(kCutoverJulianDay), fNormalizedGregorianCutover(fGregorianCutover), fGregorianCutoverYear(1582),
+fIsGregorian(TRUE), fInvertGregorian(FALSE)
+{
+    setTimeInMillis(getNow(), status);
+}
+
+// -------------------------------------
+
+GregorianCalendar::GregorianCalendar(const Locale& aLocale, UErrorCode& status)
+:   Calendar(TimeZone::createDefault(), aLocale, status),
+fGregorianCutover(kPapalCutover),
+fCutoverJulianDay(kCutoverJulianDay), fNormalizedGregorianCutover(fGregorianCutover), fGregorianCutoverYear(1582),
+fIsGregorian(TRUE), fInvertGregorian(FALSE)
+{
+    setTimeInMillis(getNow(), status);
+}
+
+// -------------------------------------
+
+GregorianCalendar::GregorianCalendar(TimeZone* zone, const Locale& aLocale,
+                                     UErrorCode& status)
+                                     :   Calendar(zone, aLocale, status),
+                                     fGregorianCutover(kPapalCutover),
+                                     fCutoverJulianDay(kCutoverJulianDay), fNormalizedGregorianCutover(fGregorianCutover), fGregorianCutoverYear(1582),
+                                     fIsGregorian(TRUE), fInvertGregorian(FALSE)
+{
+    setTimeInMillis(getNow(), status);
+}
+
+// -------------------------------------
+
+GregorianCalendar::GregorianCalendar(const TimeZone& zone, const Locale& aLocale,
+                                     UErrorCode& status)
+                                     :   Calendar(zone, aLocale, status),
+                                     fGregorianCutover(kPapalCutover),
+                                     fCutoverJulianDay(kCutoverJulianDay), fNormalizedGregorianCutover(fGregorianCutover), fGregorianCutoverYear(1582),
+                                     fIsGregorian(TRUE), fInvertGregorian(FALSE)
+{
+    setTimeInMillis(getNow(), status);
+}
+
+// -------------------------------------
+
+GregorianCalendar::GregorianCalendar(int32_t year, int32_t month, int32_t date,
+                                     UErrorCode& status)
+                                     :   Calendar(TimeZone::createDefault(), Locale::getDefault(), status),
+                                     fGregorianCutover(kPapalCutover),
+                                     fCutoverJulianDay(kCutoverJulianDay), fNormalizedGregorianCutover(fGregorianCutover), fGregorianCutoverYear(1582),
+                                     fIsGregorian(TRUE), fInvertGregorian(FALSE)
+{
+    set(UCAL_ERA, AD);
+    set(UCAL_YEAR, year);
+    set(UCAL_MONTH, month);
+    set(UCAL_DATE, date);
+}
+
+// -------------------------------------
+
+GregorianCalendar::GregorianCalendar(int32_t year, int32_t month, int32_t date,
+                                     int32_t hour, int32_t minute, UErrorCode& status)
+                                     :   Calendar(TimeZone::createDefault(), Locale::getDefault(), status),
+                                     fGregorianCutover(kPapalCutover),
+                                     fCutoverJulianDay(kCutoverJulianDay), fNormalizedGregorianCutover(fGregorianCutover), fGregorianCutoverYear(1582),
+                                     fIsGregorian(TRUE), fInvertGregorian(FALSE)
+{
+    set(UCAL_ERA, AD);
+    set(UCAL_YEAR, year);
+    set(UCAL_MONTH, month);
+    set(UCAL_DATE, date);
+    set(UCAL_HOUR_OF_DAY, hour);
+    set(UCAL_MINUTE, minute);
+}
+
+// -------------------------------------
+
+GregorianCalendar::GregorianCalendar(int32_t year, int32_t month, int32_t date,
+                                     int32_t hour, int32_t minute, int32_t second,
+                                     UErrorCode& status)
+                                     :   Calendar(TimeZone::createDefault(), Locale::getDefault(), status),
+                                     fGregorianCutover(kPapalCutover),
+                                     fCutoverJulianDay(kCutoverJulianDay), fNormalizedGregorianCutover(fGregorianCutover), fGregorianCutoverYear(1582),
+                                     fIsGregorian(TRUE), fInvertGregorian(FALSE)
+{
+    set(UCAL_ERA, AD);
+    set(UCAL_YEAR, year);
+    set(UCAL_MONTH, month);
+    set(UCAL_DATE, date);
+    set(UCAL_HOUR_OF_DAY, hour);
+    set(UCAL_MINUTE, minute);
+    set(UCAL_SECOND, second);
+}
+
+// -------------------------------------
+
+GregorianCalendar::~GregorianCalendar()
+{
+}
+
+// -------------------------------------
+
+GregorianCalendar::GregorianCalendar(const GregorianCalendar &source)
+:   Calendar(source),
+fGregorianCutover(source.fGregorianCutover),
+fCutoverJulianDay(source.fCutoverJulianDay), fNormalizedGregorianCutover(source.fNormalizedGregorianCutover), fGregorianCutoverYear(source.fGregorianCutoverYear),
+fIsGregorian(source.fIsGregorian), fInvertGregorian(source.fInvertGregorian)
+{
+}
+
+// -------------------------------------
+
+Calendar* GregorianCalendar::clone() const
+{
+    return new GregorianCalendar(*this);
+}
+
+// -------------------------------------
+
+GregorianCalendar &
+GregorianCalendar::operator=(const GregorianCalendar &right)
+{
+    if (this != &right)
+    {
+        Calendar::operator=(right);
+        fGregorianCutover = right.fGregorianCutover;
+        fNormalizedGregorianCutover = right.fNormalizedGregorianCutover;
+        fGregorianCutoverYear = right.fGregorianCutoverYear;
+        fCutoverJulianDay = right.fCutoverJulianDay;
+    }
+    return *this;
+}
+
+// -------------------------------------
+
+UBool GregorianCalendar::isEquivalentTo(const Calendar& other) const
+{
+    // Calendar override.
+    return Calendar::isEquivalentTo(other) &&
+        fGregorianCutover == ((GregorianCalendar*)&other)->fGregorianCutover;
+}
+
+// -------------------------------------
+
+void
+GregorianCalendar::setGregorianChange(UDate date, UErrorCode& status)
+{
+    if (U_FAILURE(status)) 
+        return;
+
+    fGregorianCutover = date;
+
+    // Precompute two internal variables which we use to do the actual
+    // cutover computations.  These are the normalized cutover, which is the
+    // midnight at or before the cutover, and the cutover year.  The
+    // normalized cutover is in pure date milliseconds; it contains no time
+    // of day or timezone component, and it used to compare against other
+    // pure date values.
+    int32_t cutoverDay = (int32_t)ClockMath::floorDivide(fGregorianCutover, (double)kOneDay);
+    fNormalizedGregorianCutover = cutoverDay * kOneDay;
+
+    // Handle the rare case of numeric overflow.  If the user specifies a
+    // change of UDate(Long.MIN_VALUE), in order to get a pure Gregorian
+    // calendar, then the epoch day is -106751991168, which when multiplied
+    // by ONE_DAY gives 9223372036794351616 -- the negative value is too
+    // large for 64 bits, and overflows into a positive value.  We correct
+    // this by using the next day, which for all intents is semantically
+    // equivalent.
+    if (cutoverDay < 0 && fNormalizedGregorianCutover > 0) {
+        fNormalizedGregorianCutover = (cutoverDay + 1) * kOneDay;
+    }
+
+    // Normalize the year so BC values are represented as 0 and negative
+    // values.
+    GregorianCalendar *cal = new GregorianCalendar(getTimeZone(), status);
+    /* test for NULL */
+    if (cal == 0) {
+        status = U_MEMORY_ALLOCATION_ERROR;
+        return;
+    }
+    if(U_FAILURE(status))
+        return;
+    cal->setTime(date, status);
+    fGregorianCutoverYear = cal->get(UCAL_YEAR, status);
+    if (cal->get(UCAL_ERA, status) == BC) 
+        fGregorianCutoverYear = 1 - fGregorianCutoverYear;
+    fCutoverJulianDay = cutoverDay;
+    delete cal;
+}
+
+
+void GregorianCalendar::handleComputeFields(int32_t julianDay, UErrorCode& status) {
+    int32_t eyear, month, dayOfMonth, dayOfYear;
+
+
+    if(U_FAILURE(status)) { 
+        return; 
+    }
+
+#if defined (U_DEBUG_CAL)
+    fprintf(stderr, "%s:%d: jd%d- (greg's %d)- [cut=%d]\n", 
+        __FILE__, __LINE__, julianDay, getGregorianDayOfYear(), fCutoverJulianDay);
+#endif
+
+
+    if (julianDay >= fCutoverJulianDay) {
+        month = getGregorianMonth();
+        dayOfMonth = getGregorianDayOfMonth();
+        dayOfYear = getGregorianDayOfYear();
+        eyear = getGregorianYear();
+    } else {
+        // The Julian epoch day (not the same as Julian Day)
+        // is zero on Saturday December 30, 0 (Gregorian).
+        int32_t julianEpochDay = julianDay - (kJan1_1JulianDay - 2);
+        eyear = (int32_t) ClockMath::floorDivide(4*julianEpochDay + 1464, 1461);
+
+        // Compute the Julian calendar day number for January 1, eyear
+        int32_t january1 = 365*(eyear-1) + ClockMath::floorDivide(eyear-1, (int32_t)4);
+        dayOfYear = (julianEpochDay - january1); // 0-based
+
+        // Julian leap years occurred historically every 4 years starting
+        // with 8 AD.  Before 8 AD the spacing is irregular; every 3 years
+        // from 45 BC to 9 BC, and then none until 8 AD.  However, we don't
+        // implement this historical detail; instead, we implement the
+        // computatinally cleaner proleptic calendar, which assumes
+        // consistent 4-year cycles throughout time.
+        UBool isLeap = ((eyear&0x3) == 0); // equiv. to (eyear%4 == 0)
+
+        // Common Julian/Gregorian calculation
+        int32_t correction = 0;
+        int32_t march1 = isLeap ? 60 : 59; // zero-based DOY for March 1
+        if (dayOfYear >= march1) {
+            correction = isLeap ? 1 : 2;
+        }
+        month = (12 * (dayOfYear + correction) + 6) / 367; // zero-based month
+        dayOfMonth = dayOfYear - (isLeap?kLeapNumDays[month]:kNumDays[month]) + 1; // one-based DOM
+        ++dayOfYear;
+#if defined (U_DEBUG_CAL)
+        //     fprintf(stderr, "%d - %d[%d] + 1\n", dayOfYear, isLeap?kLeapNumDays[month]:kNumDays[month], month );
+        //           fprintf(stderr, "%s:%d:  greg's HCF %d -> %d/%d/%d not %d/%d/%d\n", 
+        //                   __FILE__, __LINE__,julianDay,
+        //          eyear,month,dayOfMonth,
+        //          getGregorianYear(), getGregorianMonth(), getGregorianDayOfMonth()  );
+        fprintf(stderr, "%s:%d: doy %d (greg's %d)- [cut=%d]\n", 
+            __FILE__, __LINE__, dayOfYear, getGregorianDayOfYear(), fCutoverJulianDay);
+#endif
+
+    }
+
+    // [j81] if we are after the cutover in its year, shift the day of the year
+    if((eyear == fGregorianCutoverYear) && (julianDay >= fCutoverJulianDay)) {
+        //from handleComputeMonthStart
+        int32_t gregShift = Grego::gregorianShift(eyear);
+#if defined (U_DEBUG_CAL)
+        fprintf(stderr, "%s:%d:  gregorian shift %d :::  doy%d => %d [cut=%d]\n",
+            __FILE__, __LINE__,gregShift, dayOfYear, dayOfYear+gregShift, fCutoverJulianDay);
+#endif
+        dayOfYear += gregShift;
+    }
+
+    internalSet(UCAL_MONTH, month);
+    internalSet(UCAL_DAY_OF_MONTH, dayOfMonth);
+    internalSet(UCAL_DAY_OF_YEAR, dayOfYear);
+    internalSet(UCAL_EXTENDED_YEAR, eyear);
+    int32_t era = AD;
+    if (eyear < 1) {
+        era = BC;
+        eyear = 1 - eyear;
+    }
+    internalSet(UCAL_ERA, era);
+    internalSet(UCAL_YEAR, eyear);
+}
+
+
+// -------------------------------------
+
+UDate
+GregorianCalendar::getGregorianChange() const
+{
+    return fGregorianCutover;
+}
+
+// -------------------------------------
+
+UBool 
+GregorianCalendar::isLeapYear(int32_t year) const
+{
+    // MSVC complains bitterly if we try to use Grego::isLeapYear here
+    // NOTE: year&0x3 == year%4
+    return (year >= fGregorianCutoverYear ?
+        (((year&0x3) == 0) && ((year%100 != 0) || (year%400 == 0))) : // Gregorian
+    ((year&0x3) == 0)); // Julian
+}
+
+// -------------------------------------
+
+int32_t GregorianCalendar::handleComputeJulianDay(UCalendarDateFields bestField) 
+{
+    fInvertGregorian = FALSE;
+
+    int32_t jd = Calendar::handleComputeJulianDay(bestField);
+
+    if((bestField == UCAL_WEEK_OF_YEAR) &&  // if we are doing WOY calculations, we are counting relative to Jan 1 *julian*
+        (internalGet(UCAL_EXTENDED_YEAR)==fGregorianCutoverYear) && 
+        jd >= fCutoverJulianDay) { 
+            fInvertGregorian = TRUE;  // So that the Julian Jan 1 will be used in handleComputeMonthStart
+            return Calendar::handleComputeJulianDay(bestField);
+        }
+
+
+        // The following check handles portions of the cutover year BEFORE the
+        // cutover itself happens.
+        //if ((fIsGregorian==TRUE) != (jd >= fCutoverJulianDay)) {  /*  cutoverJulianDay)) { */
+        if ((fIsGregorian==TRUE) != (jd >= fCutoverJulianDay)) {  /*  cutoverJulianDay)) { */
+#if defined (U_DEBUG_CAL)
+            fprintf(stderr, "%s:%d: jd [invert] %d\n", 
+                __FILE__, __LINE__, jd);
+#endif
+            fInvertGregorian = TRUE;
+            jd = Calendar::handleComputeJulianDay(bestField);
+#if defined (U_DEBUG_CAL)
+            fprintf(stderr, "%s:%d:  fIsGregorian %s, fInvertGregorian %s - ", 
+                __FILE__, __LINE__,fIsGregorian?"T":"F", fInvertGregorian?"T":"F");
+            fprintf(stderr, " jd NOW %d\n", 
+                jd);
+#endif
+        } else {
+#if defined (U_DEBUG_CAL)
+            fprintf(stderr, "%s:%d: jd [==] %d - %sfIsGregorian %sfInvertGregorian, %d\n", 
+                __FILE__, __LINE__, jd, fIsGregorian?"T":"F", fInvertGregorian?"T":"F", bestField);
+#endif
+        }
+
+        if(fIsGregorian && (internalGet(UCAL_EXTENDED_YEAR) == fGregorianCutoverYear)) {
+            int32_t gregShift = Grego::gregorianShift(internalGet(UCAL_EXTENDED_YEAR));
+            if (bestField == UCAL_DAY_OF_YEAR) {
+#if defined (U_DEBUG_CAL)
+                fprintf(stderr, "%s:%d: [DOY%d] gregorian shift of JD %d += %d\n", 
+                    __FILE__, __LINE__, fFields[bestField],jd, gregShift);
+#endif
+                jd -= gregShift;
+            } else if ( bestField == UCAL_WEEK_OF_MONTH ) {
+                int32_t weekShift = 14;
+#if defined (U_DEBUG_CAL)
+                fprintf(stderr, "%s:%d: [WOY/WOM] gregorian week shift of %d += %d\n", 
+                    __FILE__, __LINE__, jd, weekShift);
+#endif
+                jd += weekShift; // shift by weeks for week based fields.
+            }
+        }
+
+        return jd;
+}
+
+int32_t GregorianCalendar::handleComputeMonthStart(int32_t eyear, int32_t month,
+
+                                                   UBool /* useMonth */) const
+{
+    GregorianCalendar *nonConstThis = (GregorianCalendar*)this; // cast away const
+
+    // If the month is out of range, adjust it into range, and
+    // modify the extended year value accordingly.
+    if (month < 0 || month > 11) {
+        eyear += ClockMath::floorDivide(month, 12, month);
+    }
+
+    UBool isLeap = eyear%4 == 0;
+    int32_t y = eyear-1;
+    int32_t julianDay = 365*y + ClockMath::floorDivide(y, 4) + (kJan1_1JulianDay - 3);
+
+    nonConstThis->fIsGregorian = (eyear >= fGregorianCutoverYear);
+#if defined (U_DEBUG_CAL)
+    fprintf(stderr, "%s:%d: (hcms%d/%d) fIsGregorian %s, fInvertGregorian %s\n", 
+        __FILE__, __LINE__, eyear,month, fIsGregorian?"T":"F", fInvertGregorian?"T":"F");
+#endif
+    if (fInvertGregorian) {
+        nonConstThis->fIsGregorian = !fIsGregorian;
+    }
+    if (fIsGregorian) {
+        isLeap = isLeap && ((eyear%100 != 0) || (eyear%400 == 0));
+        // Add 2 because Gregorian calendar starts 2 days after
+        // Julian calendar
+        int32_t gregShift = Grego::gregorianShift(eyear);
+#if defined (U_DEBUG_CAL)
+        fprintf(stderr, "%s:%d: (hcms%d/%d) gregorian shift of %d += %d\n", 
+            __FILE__, __LINE__, eyear, month, julianDay, gregShift);
+#endif
+        julianDay += gregShift;
+    }
+
+    // At this point julianDay indicates the day BEFORE the first
+    // day of January 1, <eyear> of either the Julian or Gregorian
+    // calendar.
+
+    if (month != 0) {
+        julianDay += isLeap?kLeapNumDays[month]:kNumDays[month];
+    }
+
+    return julianDay;
+}
+
+int32_t GregorianCalendar::handleGetMonthLength(int32_t extendedYear, int32_t month)  const
+{
+    // If the month is out of range, adjust it into range, and
+    // modify the extended year value accordingly.
+    if (month < 0 || month > 11) {
+        extendedYear += ClockMath::floorDivide(month, 12, month);
+    }
+
+    return isLeapYear(extendedYear) ? kLeapMonthLength[month] : kMonthLength[month];
+}
+
+int32_t GregorianCalendar::handleGetYearLength(int32_t eyear) const {
+    return isLeapYear(eyear) ? 366 : 365;
+}
+
+
+int32_t
+GregorianCalendar::monthLength(int32_t month) const
+{
+    int32_t year = internalGet(UCAL_EXTENDED_YEAR);
+    return handleGetMonthLength(year, month);
+}
+
+// -------------------------------------
+
+int32_t
+GregorianCalendar::monthLength(int32_t month, int32_t year) const
+{
+    return isLeapYear(year) ? kLeapMonthLength[month] : kMonthLength[month];
+}
+
+// -------------------------------------
+
+int32_t
+GregorianCalendar::yearLength(int32_t year) const
+{
+    return isLeapYear(year) ? 366 : 365;
+}
+
+// -------------------------------------
+
+int32_t
+GregorianCalendar::yearLength() const
+{
+    return isLeapYear(internalGet(UCAL_YEAR)) ? 366 : 365;
+}
+
+// -------------------------------------
+
+/**
+* After adjustments such as add(MONTH), add(YEAR), we don't want the
+* month to jump around.  E.g., we don't want Jan 31 + 1 month to go to Mar
+* 3, we want it to go to Feb 28.  Adjustments which might run into this
+* problem call this method to retain the proper month.
+*/
+void 
+GregorianCalendar::pinDayOfMonth() 
+{
+    int32_t monthLen = monthLength(internalGet(UCAL_MONTH));
+    int32_t dom = internalGet(UCAL_DATE);
+    if(dom > monthLen) 
+        set(UCAL_DATE, monthLen);
+}
+
+// -------------------------------------
+
+
+UBool
+GregorianCalendar::validateFields() const
+{
+    for (int32_t field = 0; field < UCAL_FIELD_COUNT; field++) {
+        // Ignore DATE and DAY_OF_YEAR which are handled below
+        if (field != UCAL_DATE &&
+            field != UCAL_DAY_OF_YEAR &&
+            isSet((UCalendarDateFields)field) &&
+            ! boundsCheck(internalGet((UCalendarDateFields)field), (UCalendarDateFields)field))
+            return FALSE;
+    }
+
+    // Values differ in Least-Maximum and Maximum should be handled
+    // specially.
+    if (isSet(UCAL_DATE)) {
+        int32_t date = internalGet(UCAL_DATE);
+        if (date < getMinimum(UCAL_DATE) ||
+            date > monthLength(internalGet(UCAL_MONTH))) {
+                return FALSE;
+            }
+    }
+
+    if (isSet(UCAL_DAY_OF_YEAR)) {
+        int32_t days = internalGet(UCAL_DAY_OF_YEAR);
+        if (days < 1 || days > yearLength()) {
+            return FALSE;
+        }
+    }
+
+    // Handle DAY_OF_WEEK_IN_MONTH, which must not have the value zero.
+    // We've checked against minimum and maximum above already.
+    if (isSet(UCAL_DAY_OF_WEEK_IN_MONTH) &&
+        0 == internalGet(UCAL_DAY_OF_WEEK_IN_MONTH)) {
+            return FALSE;
+        }
+
+        return TRUE;
+}
+
+// -------------------------------------
+
+UBool
+GregorianCalendar::boundsCheck(int32_t value, UCalendarDateFields field) const
+{
+    return value >= getMinimum(field) && value <= getMaximum(field);
+}
+
+// -------------------------------------
+
+UDate 
+GregorianCalendar::getEpochDay(UErrorCode& status) 
+{
+    complete(status);
+    // Divide by 1000 (convert to seconds) in order to prevent overflow when
+    // dealing with UDate(Long.MIN_VALUE) and UDate(Long.MAX_VALUE).
+    double wallSec = internalGetTime()/1000 + (internalGet(UCAL_ZONE_OFFSET) + internalGet(UCAL_DST_OFFSET))/1000;
+
+    return ClockMath::floorDivide(wallSec, kOneDay/1000.0);
+}
+
+// -------------------------------------
+
+
+// -------------------------------------
+
+/**
+* Compute the julian day number of the day BEFORE the first day of
+* January 1, year 1 of the given calendar.  If julianDay == 0, it
+* specifies (Jan. 1, 1) - 1, in whatever calendar we are using (Julian
+* or Gregorian).
+*/
+double GregorianCalendar::computeJulianDayOfYear(UBool isGregorian,
+                                                 int32_t year, UBool& isLeap)
+{
+    isLeap = year%4 == 0;
+    int32_t y = year - 1;
+    double julianDay = 365.0*y + ClockMath::floorDivide(y, 4) + (kJan1_1JulianDay - 3);
+
+    if (isGregorian) {
+        isLeap = isLeap && ((year%100 != 0) || (year%400 == 0));
+        // Add 2 because Gregorian calendar starts 2 days after Julian calendar
+        julianDay += Grego::gregorianShift(year);
+    }
+
+    return julianDay;
+}
+
+// /**
+//  * Compute the day of week, relative to the first day of week, from
+//  * 0..6, of the current DOW_LOCAL or DAY_OF_WEEK fields.  This is
+//  * equivalent to get(DOW_LOCAL) - 1.
+//  */
+// int32_t GregorianCalendar::computeRelativeDOW() const {
+//     int32_t relDow = 0;
+//     if (fStamp[UCAL_DOW_LOCAL] > fStamp[UCAL_DAY_OF_WEEK]) {
+//         relDow = internalGet(UCAL_DOW_LOCAL) - 1; // 1-based
+//     } else if (fStamp[UCAL_DAY_OF_WEEK] != kUnset) {
+//         relDow = internalGet(UCAL_DAY_OF_WEEK) - getFirstDayOfWeek();
+//         if (relDow < 0) relDow += 7;
+//     }
+//     return relDow;
+// }
+
+// /**
+//  * Compute the day of week, relative to the first day of week,
+//  * from 0..6 of the given julian day.
+//  */
+// int32_t GregorianCalendar::computeRelativeDOW(double julianDay) const {
+//   int32_t relDow = julianDayToDayOfWeek(julianDay) - getFirstDayOfWeek();
+//     if (relDow < 0) {
+//         relDow += 7;
+//     }
+//     return relDow;
+// }
+
+// /**
+//  * Compute the DOY using the WEEK_OF_YEAR field and the julian day
+//  * of the day BEFORE January 1 of a year (a return value from
+//  * computeJulianDayOfYear).
+//  */
+// int32_t GregorianCalendar::computeDOYfromWOY(double julianDayOfYear) const {
+//     // Compute DOY from day of week plus week of year
+
+//     // Find the day of the week for the first of this year.  This
+//     // is zero-based, with 0 being the locale-specific first day of
+//     // the week.  Add 1 to get first day of year.
+//     int32_t fdy = computeRelativeDOW(julianDayOfYear + 1);
+
+//     return
+//         // Compute doy of first (relative) DOW of WOY 1
+//         (((7 - fdy) < getMinimalDaysInFirstWeek())
+//          ? (8 - fdy) : (1 - fdy))
+
+//         // Adjust for the week number.
+//         + (7 * (internalGet(UCAL_WEEK_OF_YEAR) - 1))
+
+//         // Adjust for the DOW
+//         + computeRelativeDOW();
+// }
+
+// -------------------------------------
+
+double 
+GregorianCalendar::millisToJulianDay(UDate millis)
+{
+    return (double)kEpochStartAsJulianDay + ClockMath::floorDivide(millis, (double)kOneDay);
+}
+
+// -------------------------------------
+
+UDate
+GregorianCalendar::julianDayToMillis(double julian)
+{
+    return (UDate) ((julian - kEpochStartAsJulianDay) * (double) kOneDay);
+}
+
+// -------------------------------------
+
+int32_t
+GregorianCalendar::aggregateStamp(int32_t stamp_a, int32_t stamp_b) 
+{
+    return (((stamp_a != kUnset && stamp_b != kUnset) 
+        ? uprv_max(stamp_a, stamp_b)
+        : (int32_t)kUnset));
+}
+
+// -------------------------------------
+
+/**
+* Roll a field by a signed amount.
+* Note: This will be made public later. [LIU]
+*/
+
+void 
+GregorianCalendar::roll(EDateFields field, int32_t amount, UErrorCode& status) {
+    roll((UCalendarDateFields) field, amount, status); 
+}
+
+void
+GregorianCalendar::roll(UCalendarDateFields field, int32_t amount, UErrorCode& status)
+{
+    if((amount == 0) || U_FAILURE(status)) {
+        return;
+    }
+
+    // J81 processing. (gregorian cutover)
+    UBool inCutoverMonth = FALSE;
+    int32_t cMonthLen=0; // 'c' for cutover; in days
+    int32_t cDayOfMonth=0; // no discontinuity: [0, cMonthLen)
+    double cMonthStart=0.0; // in ms
+
+    // Common code - see if we're in the cutover month of the cutover year
+    if(get(UCAL_EXTENDED_YEAR, status) == fGregorianCutoverYear) {
+        switch (field) {
+        case UCAL_DAY_OF_MONTH:
+        case UCAL_WEEK_OF_MONTH:
+            {
+                int32_t max = monthLength(internalGet(UCAL_MONTH));
+                UDate t = internalGetTime();
+                // We subtract 1 from the DAY_OF_MONTH to make it zero-based, and an
+                // additional 10 if we are after the cutover. Thus the monthStart
+                // value will be correct iff we actually are in the cutover month.
+                cDayOfMonth = internalGet(UCAL_DAY_OF_MONTH) - ((t >= fGregorianCutover) ? 10 : 0);
+                cMonthStart = t - ((cDayOfMonth - 1) * kOneDay);
+                // A month containing the cutover is 10 days shorter.
+                if ((cMonthStart < fGregorianCutover) &&
+                    (cMonthStart + (cMonthLen=(max-10))*kOneDay >= fGregorianCutover)) {
+                        inCutoverMonth = TRUE;
+                    }
+            }
+        default:
+            ;
+        }
+    }
+
+    switch (field) {
+    case UCAL_WEEK_OF_YEAR: {
+        // Unlike WEEK_OF_MONTH, WEEK_OF_YEAR never shifts the day of the
+        // week.  Also, rolling the week of the year can have seemingly
+        // strange effects simply because the year of the week of year
+        // may be different from the calendar year.  For example, the
+        // date Dec 28, 1997 is the first day of week 1 of 1998 (if
+        // weeks start on Sunday and the minimal days in first week is
+        // <= 3).
+        int32_t woy = get(UCAL_WEEK_OF_YEAR, status);
+        // Get the ISO year, which matches the week of year.  This
+        // may be one year before or after the calendar year.
+        int32_t isoYear = get(UCAL_YEAR_WOY, status);
+        int32_t isoDoy = internalGet(UCAL_DAY_OF_YEAR);
+        if (internalGet(UCAL_MONTH) == UCAL_JANUARY) {
+            if (woy >= 52) {
+                isoDoy += handleGetYearLength(isoYear);
+            }
+        } else {
+            if (woy == 1) {
+                isoDoy -= handleGetYearLength(isoYear - 1);
+            }
+        }
+        woy += amount;
+        // Do fast checks to avoid unnecessary computation:
+        if (woy < 1 || woy > 52) {
+            // Determine the last week of the ISO year.
+            // We do this using the standard formula we use
+            // everywhere in this file.  If we can see that the
+            // days at the end of the year are going to fall into
+            // week 1 of the next year, we drop the last week by
+            // subtracting 7 from the last day of the year.
+            int32_t lastDoy = handleGetYearLength(isoYear);
+            int32_t lastRelDow = (lastDoy - isoDoy + internalGet(UCAL_DAY_OF_WEEK) -
+                getFirstDayOfWeek()) % 7;
+            if (lastRelDow < 0) lastRelDow += 7;
+            if ((6 - lastRelDow) >= getMinimalDaysInFirstWeek()) lastDoy -= 7;
+            int32_t lastWoy = weekNumber(lastDoy, lastRelDow + 1);
+            woy = ((woy + lastWoy - 1) % lastWoy) + 1;
+        }
+        set(UCAL_WEEK_OF_YEAR, woy);
+        set(UCAL_YEAR_WOY,isoYear);
+        return;
+                            }
+
+    case UCAL_DAY_OF_MONTH:
+        if( !inCutoverMonth ) { 
+            Calendar::roll(field, amount, status);
+            return;
+        } else {
+            // [j81] 1582 special case for DOM
+            // The default computation works except when the current month
+            // contains the Gregorian cutover.  We handle this special case
+            // here.  [j81 - aliu]
+            double monthLen = cMonthLen * kOneDay;
+            double msIntoMonth = uprv_fmod(internalGetTime() - cMonthStart +
+                amount * kOneDay, monthLen);
+            if (msIntoMonth < 0) {
+                msIntoMonth += monthLen;
+            }
+#if defined (U_DEBUG_CAL)
+            fprintf(stderr, "%s:%d: roll DOM %d  -> %.0lf ms  \n", 
+                __FILE__, __LINE__,amount, cMonthLen, cMonthStart+msIntoMonth);
+#endif
+            setTimeInMillis(cMonthStart + msIntoMonth, status);
+            return;
+        }
+
+    case UCAL_WEEK_OF_MONTH:
+        if( !inCutoverMonth ) { 
+            Calendar::roll(field, amount, status);
+            return;
+        } else {
+#if defined (U_DEBUG_CAL)
+            fprintf(stderr, "%s:%d: roll WOM %d ??????????????????? \n", 
+                __FILE__, __LINE__,amount);
+#endif
+            // NOTE: following copied from  the old
+            //     GregorianCalendar::roll( WEEK_OF_MONTH )  code 
+
+            // This is tricky, because during the roll we may have to shift
+            // to a different day of the week.  For example:
+
+            //    s  m  t  w  r  f  s
+            //          1  2  3  4  5
+            //    6  7  8  9 10 11 12
+
+            // When rolling from the 6th or 7th back one week, we go to the
+            // 1st (assuming that the first partial week counts).  The same
+            // thing happens at the end of the month.
+
+            // The other tricky thing is that we have to figure out whether
+            // the first partial week actually counts or not, based on the
+            // minimal first days in the week.  And we have to use the
+            // correct first day of the week to delineate the week
+            // boundaries.
+
+            // Here's our algorithm.  First, we find the real boundaries of
+            // the month.  Then we discard the first partial week if it
+            // doesn't count in this locale.  Then we fill in the ends with
+            // phantom days, so that the first partial week and the last
+            // partial week are full weeks.  We then have a nice square
+            // block of weeks.  We do the usual rolling within this block,
+            // as is done elsewhere in this method.  If we wind up on one of
+            // the phantom days that we added, we recognize this and pin to
+            // the first or the last day of the month.  Easy, eh?
+
+            // Another wrinkle: To fix jitterbug 81, we have to make all this
+            // work in the oddball month containing the Gregorian cutover.
+            // This month is 10 days shorter than usual, and also contains
+            // a discontinuity in the days; e.g., the default cutover month
+            // is Oct 1582, and goes from day of month 4 to day of month 15.
+
+            // Normalize the DAY_OF_WEEK so that 0 is the first day of the week
+            // in this locale.  We have dow in 0..6.
+            int32_t dow = internalGet(UCAL_DAY_OF_WEEK) - getFirstDayOfWeek();
+            if (dow < 0) 
+                dow += 7;
+
+            // Find the day of month, compensating for cutover discontinuity.
+            int32_t dom = cDayOfMonth;
+
+            // Find the day of the week (normalized for locale) for the first
+            // of the month.
+            int32_t fdm = (dow - dom + 1) % 7;
+            if (fdm < 0) 
+                fdm += 7;
+
+            // Get the first day of the first full week of the month,
+            // including phantom days, if any.  Figure out if the first week
+            // counts or not; if it counts, then fill in phantom days.  If
+            // not, advance to the first real full week (skip the partial week).
+            int32_t start;
+            if ((7 - fdm) < getMinimalDaysInFirstWeek())
+                start = 8 - fdm; // Skip the first partial week
+            else
+                start = 1 - fdm; // This may be zero or negative
+
+            // Get the day of the week (normalized for locale) for the last
+            // day of the month.
+            int32_t monthLen = cMonthLen;
+            int32_t ldm = (monthLen - dom + dow) % 7;
+            // We know monthLen >= DAY_OF_MONTH so we skip the += 7 step here.
+
+            // Get the limit day for the blocked-off rectangular month; that
+            // is, the day which is one past the last day of the month,
+            // after the month has already been filled in with phantom days
+            // to fill out the last week.  This day has a normalized DOW of 0.
+            int32_t limit = monthLen + 7 - ldm;
+
+            // Now roll between start and (limit - 1).
+            int32_t gap = limit - start;
+            int32_t newDom = (dom + amount*7 - start) % gap;
+            if (newDom < 0) 
+                newDom += gap;
+            newDom += start;
+
+            // Finally, pin to the real start and end of the month.
+            if (newDom < 1) 
+                newDom = 1;
+            if (newDom > monthLen) 
+                newDom = monthLen;
+
+            // Set the DAY_OF_MONTH.  We rely on the fact that this field
+            // takes precedence over everything else (since all other fields
+            // are also set at this point).  If this fact changes (if the
+            // disambiguation algorithm changes) then we will have to unset
+            // the appropriate fields here so that DAY_OF_MONTH is attended
+            // to.
+
+            // If we are in the cutover month, manipulate ms directly.  Don't do
+            // this in general because it doesn't work across DST boundaries
+            // (details, details).  This takes care of the discontinuity.
+            setTimeInMillis(cMonthStart + (newDom-1)*kOneDay, status);                
+            return;
+        }
+
+    default:
+        Calendar::roll(field, amount, status);
+        return;
+    }
+}
+
+// -------------------------------------
+
+
+/**
+* Return the minimum value that this field could have, given the current date.
+* For the Gregorian calendar, this is the same as getMinimum() and getGreatestMinimum().
+* @param field    the time field.
+* @return         the minimum value that this field could have, given the current date.
+* @deprecated ICU 2.6. Use getActualMinimum(UCalendarDateFields field) instead.
+*/
+int32_t GregorianCalendar::getActualMinimum(EDateFields field) const
+{
+    return getMinimum((UCalendarDateFields)field);
+}
+
+int32_t GregorianCalendar::getActualMinimum(EDateFields field, UErrorCode& /* status */) const
+{
+    return getMinimum((UCalendarDateFields)field);
+}
+
+/**
+* Return the minimum value that this field could have, given the current date.
+* For the Gregorian calendar, this is the same as getMinimum() and getGreatestMinimum().
+* @param field    the time field.
+* @return         the minimum value that this field could have, given the current date.
+* @draft ICU 2.6.
+*/
+int32_t GregorianCalendar::getActualMinimum(UCalendarDateFields field, UErrorCode& /* status */) const
+{
+    return getMinimum(field);
+}
+
+
+// ------------------------------------
+
+/**
+* Old year limits were least max 292269054, max 292278994.
+*/
+
+/**
+* @stable ICU 2.0
+*/
+int32_t GregorianCalendar::handleGetLimit(UCalendarDateFields field, ELimitType limitType) const {
+    return kGregorianCalendarLimits[field][limitType];
+}
+
+/**
+* Return the maximum value that this field could have, given the current date.
+* For example, with the date "Feb 3, 1997" and the DAY_OF_MONTH field, the actual
+* maximum would be 28; for "Feb 3, 1996" it s 29.  Similarly for a Hebrew calendar,
+* for some years the actual maximum for MONTH is 12, and for others 13.
+* @stable ICU 2.0
+*/
+int32_t GregorianCalendar::getActualMaximum(UCalendarDateFields field, UErrorCode& status) const
+{
+    /* It is a known limitation that the code here (and in getActualMinimum)
+    * won't behave properly at the extreme limits of GregorianCalendar's
+    * representable range (except for the code that handles the YEAR
+    * field).  That's because the ends of the representable range are at
+    * odd spots in the year.  For calendars with the default Gregorian
+    * cutover, these limits are Sun Dec 02 16:47:04 GMT 292269055 BC to Sun
+    * Aug 17 07:12:55 GMT 292278994 AD, somewhat different for non-GMT
+    * zones.  As a result, if the calendar is set to Aug 1 292278994 AD,
+    * the actual maximum of DAY_OF_MONTH is 17, not 30.  If the date is Mar
+    * 31 in that year, the actual maximum month might be Jul, whereas is
+    * the date is Mar 15, the actual maximum might be Aug -- depending on
+    * the precise semantics that are desired.  Similar considerations
+    * affect all fields.  Nonetheless, this effect is sufficiently arcane
+    * that we permit it, rather than complicating the code to handle such
+    * intricacies. - liu 8/20/98
+
+    * UPDATE: No longer true, since we have pulled in the limit values on
+    * the year. - Liu 11/6/00 */
+
+    switch (field) {
+
+    case UCAL_YEAR:
+        /* The year computation is no different, in principle, from the
+        * others, however, the range of possible maxima is large.  In
+        * addition, the way we know we've exceeded the range is different.
+        * For these reasons, we use the special case code below to handle
+        * this field.
+        *
+        * The actual maxima for YEAR depend on the type of calendar:
+        *
+        *     Gregorian = May 17, 292275056 BC - Aug 17, 292278994 AD
+        *     Julian    = Dec  2, 292269055 BC - Jan  3, 292272993 AD
+        *     Hybrid    = Dec  2, 292269055 BC - Aug 17, 292278994 AD
+        *
+        * We know we've exceeded the maximum when either the month, date,
+        * time, or era changes in response to setting the year.  We don't
+        * check for month, date, and time here because the year and era are
+        * sufficient to detect an invalid year setting.  NOTE: If code is
+        * added to check the month and date in the future for some reason,
+        * Feb 29 must be allowed to shift to Mar 1 when setting the year.
+        */
+        {
+            if(U_FAILURE(status)) return 0;
+            Calendar *cal = clone();
+            if(!cal) {
+                status = U_MEMORY_ALLOCATION_ERROR;
+                return 0;
+            }
+
+            cal->setLenient(TRUE);
+
+            int32_t era = cal->get(UCAL_ERA, status);
+            UDate d = cal->getTime(status);
+
+            /* Perform a binary search, with the invariant that lowGood is a
+            * valid year, and highBad is an out of range year.
+            */
+            int32_t lowGood = kGregorianCalendarLimits[UCAL_YEAR][1];
+            int32_t highBad = kGregorianCalendarLimits[UCAL_YEAR][2]+1;
+            while ((lowGood + 1) < highBad) {
+                int32_t y = (lowGood + highBad) / 2;
+                cal->set(UCAL_YEAR, y);
+                if (cal->get(UCAL_YEAR, status) == y && cal->get(UCAL_ERA, status) == era) {
+                    lowGood = y;
+                } else {
+                    highBad = y;
+                    cal->setTime(d, status); // Restore original fields
+                }
+            }
+
+            delete cal;
+            return lowGood;
+        }
+
+    default:
+        return Calendar::getActualMaximum(field,status);
+    }
+}
+
+
+int32_t GregorianCalendar::handleGetExtendedYear() {
+    // the year to return
+    int32_t year = kEpochYear;
+
+    // year field to use
+    int32_t yearField = UCAL_EXTENDED_YEAR;
+
+    // There are three separate fields which could be used to
+    // derive the proper year.  Use the one most recently set.
+    if (fStamp[yearField] < fStamp[UCAL_YEAR])
+        yearField = UCAL_YEAR;
+    if (fStamp[yearField] < fStamp[UCAL_YEAR_WOY])
+        yearField = UCAL_YEAR_WOY;
+
+    // based on the "best" year field, get the year
+    switch(yearField) {
+    case UCAL_EXTENDED_YEAR:
+        year = internalGet(UCAL_EXTENDED_YEAR, kEpochYear);
+        break;
+
+    case UCAL_YEAR:
+        {
+            // The year defaults to the epoch start, the era to AD
+            int32_t era = internalGet(UCAL_ERA, AD);
+            if (era == BC) {
+                year = 1 - internalGet(UCAL_YEAR, 1); // Convert to extended year
+            } else {
+                year = internalGet(UCAL_YEAR, kEpochYear);
+            }
+        }
+        break;
+
+    case UCAL_YEAR_WOY:
+        year = handleGetExtendedYearFromWeekFields(internalGet(UCAL_YEAR_WOY), internalGet(UCAL_WEEK_OF_YEAR));
+#if defined (U_DEBUG_CAL)
+        //    if(internalGet(UCAL_YEAR_WOY) != year) {
+        fprintf(stderr, "%s:%d: hGEYFWF[%d,%d] ->  %d\n", 
+            __FILE__, __LINE__,internalGet(UCAL_YEAR_WOY),internalGet(UCAL_WEEK_OF_YEAR),year);
+        //}
+#endif
+        break;
+
+    default:
+        year = kEpochYear;
+    }
+    return year;
+}
+
+int32_t GregorianCalendar::handleGetExtendedYearFromWeekFields(int32_t yearWoy, int32_t woy)
+{
+    // convert year to extended form
+    int32_t era = internalGet(UCAL_ERA, AD);
+    if(era == BC) {
+        yearWoy = 1 - yearWoy;
+    }
+    return Calendar::handleGetExtendedYearFromWeekFields(yearWoy, woy);
+}
+
+
+// -------------------------------------
+
+UBool
+GregorianCalendar::inDaylightTime(UErrorCode& status) const
+{
+    if (U_FAILURE(status) || !getTimeZone().useDaylightTime()) 
+        return FALSE;
+
+    // Force an update of the state of the Calendar.
+    ((GregorianCalendar*)this)->complete(status); // cast away const
+
+    return (UBool)(U_SUCCESS(status) ? (internalGet(UCAL_DST_OFFSET) != 0) : FALSE);
+}
+
+// -------------------------------------
+
+/**
+* Return the ERA.  We need a special method for this because the
+* default ERA is AD, but a zero (unset) ERA is BC.
+*/
+int32_t
+GregorianCalendar::internalGetEra() const {
+    return isSet(UCAL_ERA) ? internalGet(UCAL_ERA) : (int32_t)AD;
+}
+
+const char *
+GregorianCalendar::getType() const {
+    //static const char kGregorianType = "gregorian";
+
+    return "gregorian";
+}
+
+const UDate     GregorianCalendar::fgSystemDefaultCentury        = DBL_MIN;
+const int32_t   GregorianCalendar::fgSystemDefaultCenturyYear    = -1;
+
+UDate           GregorianCalendar::fgSystemDefaultCenturyStart       = DBL_MIN;
+int32_t         GregorianCalendar::fgSystemDefaultCenturyStartYear   = -1;
+
+
+UBool GregorianCalendar::haveDefaultCentury() const
+{
+    return TRUE;
+}
+
+UDate GregorianCalendar::defaultCenturyStart() const
+{
+    return internalGetDefaultCenturyStart();
+}
+
+int32_t GregorianCalendar::defaultCenturyStartYear() const
+{
+    return internalGetDefaultCenturyStartYear();
+}
+
+UDate
+GregorianCalendar::internalGetDefaultCenturyStart() const
+{
+    // lazy-evaluate systemDefaultCenturyStart
+    UBool needsUpdate;
+    UMTX_CHECK(NULL, (fgSystemDefaultCenturyStart == fgSystemDefaultCentury), needsUpdate);
+
+    if (needsUpdate) {
+        initializeSystemDefaultCentury();
+    }
+
+    // use defaultCenturyStart unless it's the flag value;
+    // then use systemDefaultCenturyStart
+
+    return fgSystemDefaultCenturyStart;
+}
+
+int32_t
+GregorianCalendar::internalGetDefaultCenturyStartYear() const
+{
+    // lazy-evaluate systemDefaultCenturyStartYear
+    UBool needsUpdate;
+    UMTX_CHECK(NULL, (fgSystemDefaultCenturyStart == fgSystemDefaultCentury), needsUpdate);
+
+    if (needsUpdate) {
+        initializeSystemDefaultCentury();
+    }
+
+    // use defaultCenturyStart unless it's the flag value;
+    // then use systemDefaultCenturyStartYear
+
+    return fgSystemDefaultCenturyStartYear;
+}
+
+void
+GregorianCalendar::initializeSystemDefaultCentury()
+{
+    // initialize systemDefaultCentury and systemDefaultCenturyYear based
+    // on the current time.  They'll be set to 80 years before
+    // the current time.
+    UErrorCode status = U_ZERO_ERROR;
+    Calendar *calendar = new GregorianCalendar(status);
+    if (calendar != NULL && U_SUCCESS(status))
+    {
+        calendar->setTime(Calendar::getNow(), status);
+        calendar->add(UCAL_YEAR, -80, status);
+
+        UDate    newStart =  calendar->getTime(status);
+        int32_t  newYear  =  calendar->get(UCAL_YEAR, status);
+        umtx_lock(NULL);
+        if (fgSystemDefaultCenturyStart == fgSystemDefaultCentury)
+        {
+            fgSystemDefaultCenturyStartYear = newYear;
+            fgSystemDefaultCenturyStart = newStart;
+        }
+        umtx_unlock(NULL);
+        delete calendar;
+    }
+    // We have no recourse upon failure unless we want to propagate the failure
+    // out.
+}
+
+
+U_NAMESPACE_END
+
+#endif /* #if !UCONFIG_NO_FORMATTING */
+
+//eof