icu4c/source/i18n/calendar.cpp

// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
*******************************************************************************
* Copyright (C) 1997-2016, International Business Machines Corporation and    *
* others. All Rights Reserved.                                                *
*******************************************************************************
*
* File CALENDAR.CPP
*
* Modification History:
*
*   Date        Name        Description
*   02/03/97    clhuang     Creation.
*   04/22/97    aliu        Cleaned up, fixed memory leak, made
*                           setWeekCountData() more robust.
*                           Moved platform code to TPlatformUtilities.
*   05/01/97    aliu        Made equals(), before(), after() arguments const.
*   05/20/97    aliu        Changed logic of when to compute fields and time
*                           to fix bugs.
*   08/12/97    aliu        Added equivalentTo.  Misc other fixes.
*   07/28/98    stephen     Sync up with JDK 1.2
*   09/02/98    stephen     Sync with JDK 1.2 8/31 build (getActualMin/Max)
*   03/17/99    stephen     Changed adoptTimeZone() - now fAreFieldsSet is
*                           set to false to force update of time.
*******************************************************************************
*/

#include "utypeinfo.h"  // for 'typeid' to work

#include "unicode/utypes.h"

#if !UCONFIG_NO_FORMATTING

#include "unicode/gregocal.h"
#include "unicode/basictz.h"
#include "unicode/simpletz.h"
#include "unicode/rbtz.h"
#include "unicode/vtzone.h"
#include "gregoimp.h"
#include "buddhcal.h"
#include "taiwncal.h"
#include "japancal.h"
#include "islamcal.h"
#include "hebrwcal.h"
#include "persncal.h"
#include "indiancal.h"
#include "iso8601cal.h"
#include "chnsecal.h"
#include "coptccal.h"
#include "dangical.h"
#include "ethpccal.h"
#include "unicode/calendar.h"
#include "cpputils.h"
#include "servloc.h"
#include "ucln_in.h"
#include "cstring.h"
#include "locbased.h"
#include "uresimp.h"
#include "ustrenum.h"
#include "uassert.h"
#include "olsontz.h"
#include "sharedcalendar.h"
#include "unifiedcache.h"
#include "ulocimp.h"
#include "bytesinkutil.h"
#include "charstr.h"

#if !UCONFIG_NO_SERVICE
static icu::ICULocaleService* gService = nullptr;
static icu::UInitOnce gServiceInitOnce {};

// INTERNAL - for cleanup
U_CDECL_BEGIN
static UBool calendar_cleanup() {
#if !UCONFIG_NO_SERVICE
    if (gService) {
        delete gService;
        gService = nullptr;
    }
    gServiceInitOnce.reset();
#endif
    return true;
}
U_CDECL_END
#endif

// ------------------------------------------
//
// Registration
//
//-------------------------------------------
//#define U_DEBUG_CALSVC 1
//

#if defined( U_DEBUG_CALSVC ) || defined (U_DEBUG_CAL)

/**
 * fldName was removed as a duplicate implementation.
 * use  udbg_ services instead,
 * which depend on include files and library from ../tools/toolutil, the following circular link:
 *   CPPFLAGS+=-I$(top_srcdir)/tools/toolutil
 *   LIBS+=$(LIBICUTOOLUTIL)
 */
#include "udbgutil.h"
#include <stdio.h>

/**
* convert a UCalendarDateFields into a string - for debugging
* @param f field enum
* @return static string to the field name
* @internal
*/

const char* fldName(UCalendarDateFields f) {
    return udbg_enumName(UDBG_UCalendarDateFields, (int32_t)f);
}

#if UCAL_DEBUG_DUMP
// from CalendarTest::calToStr - but doesn't modify contents.
void ucal_dump(const Calendar &cal) {
    cal.dump();
}

void Calendar::dump() const {
    int i;
    fprintf(stderr, "@calendar=%s, timeset=%c, fieldset=%c, allfields=%c, virtualset=%c, t=%.2f",
        getType(), fIsTimeSet?'y':'n',  fAreFieldsSet?'y':'n',  fAreAllFieldsSet?'y':'n',
        fAreFieldsVirtuallySet?'y':'n',
        fTime);

    // can add more things here: DST, zone, etc.
    fprintf(stderr, "\n");
    for(i = 0;i<UCAL_FIELD_COUNT;i++) {
        int n;
        const char *f = fldName((UCalendarDateFields)i);
        fprintf(stderr, "  %25s: %-11ld", f, fFields[i]);
        if(fStamp[i] == kUnset) {
            fprintf(stderr, " (unset) ");
        } else if(fStamp[i] == kInternallySet) {
            fprintf(stderr, " (internally set) ");
            //} else if(fStamp[i] == kInternalDefault) {
            //    fprintf(stderr, " (internal default) ");
        } else {
            fprintf(stderr, " %%%d ", fStamp[i]);
        }
        fprintf(stderr, "\n");

    }
}

U_CFUNC void ucal_dump(UCalendar* cal) {
    ucal_dump( *((Calendar*)cal)  );
}
#endif

#endif

/* Max value for stamp allowable before recalculation */
#define STAMP_MAX 10000

static const char * const gCalTypes[] = {
    "gregorian",
    "japanese",
    "buddhist",
    "roc",
    "persian",
    "islamic-civil",
    "islamic",
    "hebrew",
    "chinese",
    "indian",
    "coptic",
    "ethiopic",
    "ethiopic-amete-alem",
    "iso8601",
    "dangi",
    "islamic-umalqura",
    "islamic-tbla",
    "islamic-rgsa",
    nullptr
};

// Must be in the order of gCalTypes above
typedef enum ECalType {
    CALTYPE_UNKNOWN = -1,
    CALTYPE_GREGORIAN = 0,
    CALTYPE_JAPANESE,
    CALTYPE_BUDDHIST,
    CALTYPE_ROC,
    CALTYPE_PERSIAN,
    CALTYPE_ISLAMIC_CIVIL,
    CALTYPE_ISLAMIC,
    CALTYPE_HEBREW,
    CALTYPE_CHINESE,
    CALTYPE_INDIAN,
    CALTYPE_COPTIC,
    CALTYPE_ETHIOPIC,
    CALTYPE_ETHIOPIC_AMETE_ALEM,
    CALTYPE_ISO8601,
    CALTYPE_DANGI,
    CALTYPE_ISLAMIC_UMALQURA,
    CALTYPE_ISLAMIC_TBLA,
    CALTYPE_ISLAMIC_RGSA
} ECalType;

U_NAMESPACE_BEGIN

SharedCalendar::~SharedCalendar() {
    delete ptr;
}

template<> U_I18N_API
const SharedCalendar *LocaleCacheKey<SharedCalendar>::createObject(
        const void * /*unusedCreationContext*/, UErrorCode &status) const {
    if (U_FAILURE(status)) {
       return nullptr;
    }
    Calendar *calendar = Calendar::makeInstance(fLoc, status);
    if (U_FAILURE(status)) {
        return nullptr;
    }
    SharedCalendar *shared = new SharedCalendar(calendar);
    if (shared == nullptr) {
        delete calendar;
        status = U_MEMORY_ALLOCATION_ERROR;
        return nullptr;
    }
    shared->addRef();
    return shared;
}

static ECalType getCalendarType(const char *s) {
    for (int i = 0; gCalTypes[i] != nullptr; i++) {
        if (uprv_stricmp(s, gCalTypes[i]) == 0) {
            return (ECalType)i;
        }
    }
    return CALTYPE_UNKNOWN;
}

#if !UCONFIG_NO_SERVICE
// Only used with service registration.
static UBool isStandardSupportedKeyword(const char *keyword, UErrorCode& status) {
    if(U_FAILURE(status)) {
        return false;
    }
    ECalType calType = getCalendarType(keyword);
    return (calType != CALTYPE_UNKNOWN);
}

#endif

static ECalType getCalendarTypeForLocale(const char *locid) {
    UErrorCode status = U_ZERO_ERROR;
    ECalType calType = CALTYPE_UNKNOWN;

    //TODO: ULOC_FULL_NAME is out of date and too small..
    char canonicalName[256];

    // Canonicalize, so that an old-style variant will be transformed to keywords.
    // e.g ja_JP_TRADITIONAL -> ja_JP@calendar=japanese
    // NOTE: Since ICU-20187, ja_JP_TRADITIONAL no longer canonicalizes, and
    // the Gregorian calendar is returned instead.
    int32_t canonicalLen = uloc_canonicalize(locid, canonicalName, sizeof(canonicalName) - 1, &status);
    if (U_FAILURE(status)) {
        return CALTYPE_GREGORIAN;
    }
    canonicalName[canonicalLen] = 0;    // terminate

    CharString calTypeBuf;
    {
        CharStringByteSink sink(&calTypeBuf);
        ulocimp_getKeywordValue(canonicalName, "calendar", sink, &status);
    }
    if (U_SUCCESS(status)) {
        calType = getCalendarType(calTypeBuf.data());
        if (calType != CALTYPE_UNKNOWN) {
            return calType;
        }
    }
    status = U_ZERO_ERROR;

    // when calendar keyword is not available or not supported, read supplementalData
    // to get the default calendar type for the locale's region
    char region[ULOC_COUNTRY_CAPACITY];
    (void)ulocimp_getRegionForSupplementalData(canonicalName, true, region, sizeof(region), &status);
    if (U_FAILURE(status)) {
        return CALTYPE_GREGORIAN;
    }

    // Read preferred calendar values from supplementalData calendarPreference
    UResourceBundle *rb = ures_openDirect(nullptr, "supplementalData", &status);
    ures_getByKey(rb, "calendarPreferenceData", rb, &status);
    UResourceBundle *order = ures_getByKey(rb, region, nullptr, &status);
    if (status == U_MISSING_RESOURCE_ERROR && rb != nullptr) {
        status = U_ZERO_ERROR;
        order = ures_getByKey(rb, "001", nullptr, &status);
    }

    calTypeBuf.clear();
    if (U_SUCCESS(status) && order != nullptr) {
        // the first calendar type is the default for the region
        int32_t len = 0;
        const char16_t *uCalType = ures_getStringByIndex(order, 0, &len, &status);
        calTypeBuf.appendInvariantChars(uCalType, len, status);
        calType = getCalendarType(calTypeBuf.data());
    }

    ures_close(order);
    ures_close(rb);

    if (calType == CALTYPE_UNKNOWN) {
        // final fallback
        calType = CALTYPE_GREGORIAN;
    }
    return calType;
}

static Calendar *createStandardCalendar(ECalType calType, const Locale &loc, UErrorCode& status) {
    if (U_FAILURE(status)) {
        return nullptr;
    }
    LocalPointer<Calendar> cal;

    switch (calType) {
        case CALTYPE_GREGORIAN:
            cal.adoptInsteadAndCheckErrorCode(new GregorianCalendar(loc, status), status);
            break;
        case CALTYPE_JAPANESE:
            cal.adoptInsteadAndCheckErrorCode(new JapaneseCalendar(loc, status), status);
            break;
        case CALTYPE_BUDDHIST:
            cal.adoptInsteadAndCheckErrorCode(new BuddhistCalendar(loc, status), status);
            break;
        case CALTYPE_ROC:
            cal.adoptInsteadAndCheckErrorCode(new TaiwanCalendar(loc, status), status);
            break;
        case CALTYPE_PERSIAN:
            cal.adoptInsteadAndCheckErrorCode(new PersianCalendar(loc, status), status);
            break;
        case CALTYPE_ISLAMIC_TBLA:
            cal.adoptInsteadAndCheckErrorCode(new IslamicTBLACalendar(loc, status), status);
            break;
        case CALTYPE_ISLAMIC_CIVIL:
            cal.adoptInsteadAndCheckErrorCode(new IslamicCivilCalendar(loc, status), status);
            break;
        case CALTYPE_ISLAMIC_RGSA:
            cal.adoptInsteadAndCheckErrorCode(new IslamicRGSACalendar(loc, status), status);
            break;
        case CALTYPE_ISLAMIC:
            cal.adoptInsteadAndCheckErrorCode(new IslamicCalendar(loc, status), status);
            break;
        case CALTYPE_ISLAMIC_UMALQURA:
            cal.adoptInsteadAndCheckErrorCode(new IslamicUmalquraCalendar(loc, status), status);
            break;
        case CALTYPE_HEBREW:
            cal.adoptInsteadAndCheckErrorCode(new HebrewCalendar(loc, status), status);
            break;
        case CALTYPE_CHINESE:
            cal.adoptInsteadAndCheckErrorCode(new ChineseCalendar(loc, status), status);
            break;
        case CALTYPE_INDIAN:
            cal.adoptInsteadAndCheckErrorCode(new IndianCalendar(loc, status), status);
            break;
        case CALTYPE_COPTIC:
            cal.adoptInsteadAndCheckErrorCode(new CopticCalendar(loc, status), status);
            break;
        case CALTYPE_ETHIOPIC:
            cal.adoptInsteadAndCheckErrorCode(new EthiopicCalendar(loc, status), status);
            break;
        case CALTYPE_ETHIOPIC_AMETE_ALEM:
            cal.adoptInsteadAndCheckErrorCode(new EthiopicAmeteAlemCalendar(loc, status), status);
            break;
        case CALTYPE_ISO8601:
            cal.adoptInsteadAndCheckErrorCode(new ISO8601Calendar(loc, status), status);
            break;
        case CALTYPE_DANGI:
            cal.adoptInsteadAndCheckErrorCode(new DangiCalendar(loc, status), status);
            break;
        default:
            status = U_UNSUPPORTED_ERROR;
    }
    return cal.orphan();
}


#if !UCONFIG_NO_SERVICE

// -------------------------------------

/**
* a Calendar Factory which creates the "basic" calendar types, that is, those
* shipped with ICU.
*/
class BasicCalendarFactory : public LocaleKeyFactory {
public:
    /**
    * @param calendarType static const string (caller owns storage - will be aliased) to calendar type
    */
    BasicCalendarFactory()
        : LocaleKeyFactory(LocaleKeyFactory::INVISIBLE) { }

    virtual ~BasicCalendarFactory();

protected:
    //virtual UBool isSupportedID( const UnicodeString& id, UErrorCode& status) const {
    //  if(U_FAILURE(status)) {
    //    return false;
    //  }
    //  char keyword[ULOC_FULLNAME_CAPACITY];
    //  getCalendarKeyword(id, keyword, (int32_t)sizeof(keyword));
    //  return isStandardSupportedKeyword(keyword, status);
    //}

    virtual void updateVisibleIDs(Hashtable& result, UErrorCode& status) const override
    {
        if (U_SUCCESS(status)) {
            for(int32_t i=0;gCalTypes[i] != nullptr;i++) {
                UnicodeString id((char16_t)0x40); /* '@' a variant character */
                id.append(UNICODE_STRING_SIMPLE("calendar="));
                id.append(UnicodeString(gCalTypes[i], -1, US_INV));
                result.put(id, (void*)this, status);
            }
        }
    }

    virtual UObject* create(const ICUServiceKey& key, const ICUService* /*service*/, UErrorCode& status) const override {
        if (U_FAILURE(status)) {
           return nullptr;
        }
#ifdef U_DEBUG_CALSVC
        if(dynamic_cast<const LocaleKey*>(&key) == nullptr) {
            fprintf(stderr, "::create - not a LocaleKey!\n");
        }
#endif
        const LocaleKey* lkey = dynamic_cast<const LocaleKey*>(&key);
        U_ASSERT(lkey != nullptr);
        Locale curLoc;  // current locale
        Locale canLoc;  // Canonical locale

        lkey->currentLocale(curLoc);
        lkey->canonicalLocale(canLoc);

        char keyword[ULOC_FULLNAME_CAPACITY];
        curLoc.getKeywordValue("calendar", keyword, (int32_t) sizeof(keyword), status);

#ifdef U_DEBUG_CALSVC
        fprintf(stderr, "BasicCalendarFactory::create() - cur %s, can %s\n", (const char*)curLoc.getName(), (const char*)canLoc.getName());
#endif

        if(!isStandardSupportedKeyword(keyword,status)) {  // Do we handle this type?
#ifdef U_DEBUG_CALSVC

            fprintf(stderr, "BasicCalendarFactory - not handling %s.[%s]\n", (const char*) curLoc.getName(), tmp );
#endif
            return nullptr;
        }

        return createStandardCalendar(getCalendarType(keyword), canLoc, status);
    }
};

BasicCalendarFactory::~BasicCalendarFactory() {}

/**
* A factory which looks up the DefaultCalendar resource to determine which class of calendar to use
*/

class DefaultCalendarFactory : public ICUResourceBundleFactory {
public:
    DefaultCalendarFactory() : ICUResourceBundleFactory() { }
    virtual ~DefaultCalendarFactory();
protected:
    virtual UObject* create(const ICUServiceKey& key, const ICUService* /*service*/, UErrorCode& status) const override {
        if (U_FAILURE(status)) {
           return nullptr;
        }

        const LocaleKey *lkey = dynamic_cast<const LocaleKey*>(&key);
        U_ASSERT(lkey != nullptr);
        Locale loc;
        lkey->currentLocale(loc);

        UnicodeString *ret = new UnicodeString();
        if (ret == nullptr) {
            status = U_MEMORY_ALLOCATION_ERROR;
        } else {
            ret->append((char16_t)0x40); // '@' is a variant character
            ret->append(UNICODE_STRING("calendar=", 9));
            ret->append(UnicodeString(gCalTypes[getCalendarTypeForLocale(loc.getName())], -1, US_INV));
        }
        return ret;
    }
};

DefaultCalendarFactory::~DefaultCalendarFactory() {}

// -------------------------------------
class CalendarService : public ICULocaleService {
public:
    CalendarService()
        : ICULocaleService(UNICODE_STRING_SIMPLE("Calendar"))
    {
        UErrorCode status = U_ZERO_ERROR;
        registerFactory(new DefaultCalendarFactory(), status);
    }

    virtual ~CalendarService();

    virtual UObject* cloneInstance(UObject* instance) const override {
        UnicodeString *s = dynamic_cast<UnicodeString *>(instance);
        if(s != nullptr) {
            return s->clone();
        } else {
#ifdef U_DEBUG_CALSVC_F
            UErrorCode status2 = U_ZERO_ERROR;
            fprintf(stderr, "Cloning a %s calendar with tz=%ld\n", ((Calendar*)instance)->getType(), ((Calendar*)instance)->get(UCAL_ZONE_OFFSET, status2));
#endif
            return ((Calendar*)instance)->clone();
        }
    }

    virtual UObject* handleDefault(const ICUServiceKey& key, UnicodeString* /*actualID*/, UErrorCode& status) const override {
        if (U_FAILURE(status)) {
           return nullptr;
        }
        LocaleKey& lkey = static_cast<LocaleKey&>(const_cast<ICUServiceKey&>(key));
        //int32_t kind = lkey.kind();

        Locale loc;
        lkey.canonicalLocale(loc);

#ifdef U_DEBUG_CALSVC
        Locale loc2;
        lkey.currentLocale(loc2);
        fprintf(stderr, "CalSvc:handleDefault for currentLoc %s, canloc %s\n", (const char*)loc.getName(),  (const char*)loc2.getName());
#endif
        Calendar *nc =  new GregorianCalendar(loc, status);
        if (nc == nullptr) {
            status = U_MEMORY_ALLOCATION_ERROR;
            return nc;
        }

#ifdef U_DEBUG_CALSVC
        UErrorCode status2 = U_ZERO_ERROR;
        fprintf(stderr, "New default calendar has tz=%d\n", ((Calendar*)nc)->get(UCAL_ZONE_OFFSET, status2));
#endif
        return nc;
    }

    virtual UBool isDefault() const override {
        return countFactories() == 1;
    }
};

CalendarService::~CalendarService() {}

// -------------------------------------

static inline UBool
isCalendarServiceUsed() {
    return !gServiceInitOnce.isReset();
}

// -------------------------------------

static void U_CALLCONV
initCalendarService(UErrorCode &status)
{
#ifdef U_DEBUG_CALSVC
        fprintf(stderr, "Spinning up Calendar Service\n");
#endif
    if (U_FAILURE(status)) {
       return;
    }
    ucln_i18n_registerCleanup(UCLN_I18N_CALENDAR, calendar_cleanup);
    gService = new CalendarService();
    if (gService == nullptr) {
            status = U_MEMORY_ALLOCATION_ERROR;
        return;
        }
#ifdef U_DEBUG_CALSVC
        fprintf(stderr, "Registering classes..\n");
#endif

        // Register all basic instances.
    gService->registerFactory(new BasicCalendarFactory(),status);

#ifdef U_DEBUG_CALSVC
        fprintf(stderr, "Done..\n");
#endif

        if(U_FAILURE(status)) {
#ifdef U_DEBUG_CALSVC
            fprintf(stderr, "err (%s) registering classes, deleting service.....\n", u_errorName(status));
#endif
        delete gService;
        gService = nullptr;
    }
        }

static ICULocaleService*
getCalendarService(UErrorCode &status)
{
    umtx_initOnce(gServiceInitOnce, &initCalendarService, status);
    return gService;
}

URegistryKey Calendar::registerFactory(ICUServiceFactory* toAdopt, UErrorCode& status)
{
    return getCalendarService(status)->registerFactory(toAdopt, status);
}

UBool Calendar::unregister(URegistryKey key, UErrorCode& status) {
    return getCalendarService(status)->unregister(key, status);
}
#endif /* UCONFIG_NO_SERVICE */

// -------------------------------------

static const int32_t kCalendarLimits[UCAL_FIELD_COUNT][4] = {
    //    Minimum  Greatest min      Least max   Greatest max
    {/*N/A*/-1,       /*N/A*/-1,     /*N/A*/-1,       /*N/A*/-1}, // ERA
    {/*N/A*/-1,       /*N/A*/-1,     /*N/A*/-1,       /*N/A*/-1}, // YEAR
    {/*N/A*/-1,       /*N/A*/-1,     /*N/A*/-1,       /*N/A*/-1}, // MONTH
    {/*N/A*/-1,       /*N/A*/-1,     /*N/A*/-1,       /*N/A*/-1}, // WEEK_OF_YEAR
    {/*N/A*/-1,       /*N/A*/-1,     /*N/A*/-1,       /*N/A*/-1}, // WEEK_OF_MONTH
    {/*N/A*/-1,       /*N/A*/-1,     /*N/A*/-1,       /*N/A*/-1}, // DAY_OF_MONTH
    {/*N/A*/-1,       /*N/A*/-1,     /*N/A*/-1,       /*N/A*/-1}, // DAY_OF_YEAR
    {           1,            1,             7,             7  }, // DAY_OF_WEEK
    {/*N/A*/-1,       /*N/A*/-1,     /*N/A*/-1,       /*N/A*/-1}, // DAY_OF_WEEK_IN_MONTH
    {           0,            0,             1,             1  }, // AM_PM
    {           0,            0,            11,            11  }, // HOUR
    {           0,            0,            23,            23  }, // HOUR_OF_DAY
    {           0,            0,            59,            59  }, // MINUTE
    {           0,            0,            59,            59  }, // SECOND
    {           0,            0,           999,           999  }, // MILLISECOND
    {-16*kOneHour, -16*kOneHour,   12*kOneHour,   30*kOneHour  }, // ZONE_OFFSET
    { -1*kOneHour,  -1*kOneHour,    2*kOneHour,    2*kOneHour  }, // DST_OFFSET
    {/*N/A*/-1,       /*N/A*/-1,     /*N/A*/-1,       /*N/A*/-1}, // YEAR_WOY
    {           1,            1,             7,             7  }, // DOW_LOCAL
    {/*N/A*/-1,       /*N/A*/-1,     /*N/A*/-1,       /*N/A*/-1}, // EXTENDED_YEAR
    { -0x7F000000,  -0x7F000000,    0x7F000000,    0x7F000000  }, // JULIAN_DAY
    {           0,            0, 24*kOneHour-1, 24*kOneHour-1  }, // MILLISECONDS_IN_DAY
    {           0,            0,             1,             1  }, // IS_LEAP_MONTH
    {           0,            0,            11,            11  }  // ORDINAL_MONTH
};

// Resource bundle tags read by this class
static const char gCalendar[] = "calendar";
static const char gMonthNames[] = "monthNames";
static const char gGregorian[] = "gregorian";

// Data flow in Calendar
// ---------------------

// The current time is represented in two ways by Calendar: as UTC
// milliseconds from the epoch start (1 January 1970 0:00 UTC), and as local
// fields such as MONTH, HOUR, AM_PM, etc.  It is possible to compute the
// millis from the fields, and vice versa.  The data needed to do this
// conversion is encapsulated by a TimeZone object owned by the Calendar.
// The data provided by the TimeZone object may also be overridden if the
// user sets the ZONE_OFFSET and/or DST_OFFSET fields directly. The class
// keeps track of what information was most recently set by the caller, and
// uses that to compute any other information as needed.

// If the user sets the fields using set(), the data flow is as follows.
// This is implemented by the Calendar subclass's computeTime() method.
// During this process, certain fields may be ignored.  The disambiguation
// algorithm for resolving which fields to pay attention to is described
// above.

//   local fields (YEAR, MONTH, DATE, HOUR, MINUTE, etc.)
//           |
//           | Using Calendar-specific algorithm
//           V
//   local standard millis
//           |
//           | Using TimeZone or user-set ZONE_OFFSET / DST_OFFSET
//           V
//   UTC millis (in time data member)

// If the user sets the UTC millis using setTime(), the data flow is as
// follows.  This is implemented by the Calendar subclass's computeFields()
// method.

//   UTC millis (in time data member)
//           |
//           | Using TimeZone getOffset()
//           V
//   local standard millis
//           |
//           | Using Calendar-specific algorithm
//           V
//   local fields (YEAR, MONTH, DATE, HOUR, MINUTE, etc.)

// In general, a round trip from fields, through local and UTC millis, and
// back out to fields is made when necessary.  This is implemented by the
// complete() method.  Resolving a partial set of fields into a UTC millis
// value allows all remaining fields to be generated from that value.  If
// the Calendar is lenient, the fields are also renormalized to standard
// ranges when they are regenerated.

// -------------------------------------

Calendar::Calendar(UErrorCode& success)
:   UObject(),
fIsTimeSet(false),
fAreFieldsSet(false),
fAreAllFieldsSet(false),
fAreFieldsVirtuallySet(false),
fNextStamp((int32_t)kMinimumUserStamp),
fTime(0),
fLenient(true),
fZone(nullptr),
fRepeatedWallTime(UCAL_WALLTIME_LAST),
fSkippedWallTime(UCAL_WALLTIME_LAST)
{
    validLocale[0] = 0;
    actualLocale[0] = 0;
    clear();
    if (U_FAILURE(success)) {
        return;
    }
    fZone = TimeZone::createDefault();
    if (fZone == nullptr) {
        success = U_MEMORY_ALLOCATION_ERROR;
    }
    setWeekData(Locale::getDefault(), nullptr, success);
}

// -------------------------------------

Calendar::Calendar(TimeZone* zone, const Locale& aLocale, UErrorCode& success)
:   UObject(),
fIsTimeSet(false),
fAreFieldsSet(false),
fAreAllFieldsSet(false),
fAreFieldsVirtuallySet(false),
fNextStamp((int32_t)kMinimumUserStamp),
fTime(0),
fLenient(true),
fZone(nullptr),
fRepeatedWallTime(UCAL_WALLTIME_LAST),
fSkippedWallTime(UCAL_WALLTIME_LAST)
{
    validLocale[0] = 0;
    actualLocale[0] = 0;
    if (U_FAILURE(success)) {
        delete zone;
        return;
    }
    if(zone == 0) {
#if defined (U_DEBUG_CAL)
        fprintf(stderr, "%s:%d: ILLEGAL ARG because timezone cannot be 0\n",
            __FILE__, __LINE__);
#endif
        success = U_ILLEGAL_ARGUMENT_ERROR;
        return;
    }

    clear();
    fZone = zone;
    setWeekData(aLocale, nullptr, success);
}

// -------------------------------------

Calendar::Calendar(const TimeZone& zone, const Locale& aLocale, UErrorCode& success)
:   UObject(),
fIsTimeSet(false),
fAreFieldsSet(false),
fAreAllFieldsSet(false),
fAreFieldsVirtuallySet(false),
fNextStamp((int32_t)kMinimumUserStamp),
fTime(0),
fLenient(true),
fZone(nullptr),
fRepeatedWallTime(UCAL_WALLTIME_LAST),
fSkippedWallTime(UCAL_WALLTIME_LAST)
{
    validLocale[0] = 0;
    actualLocale[0] = 0;
    if (U_FAILURE(success)) {
        return;
    }
    clear();
    fZone = zone.clone();
    if (fZone == nullptr) {
        success = U_MEMORY_ALLOCATION_ERROR;
    }
    setWeekData(aLocale, nullptr, success);
}

// -------------------------------------

Calendar::~Calendar()
{
    delete fZone;
}

// -------------------------------------

Calendar::Calendar(const Calendar &source)
:   UObject(source)
{
    fZone = nullptr;
    *this = source;
}

// -------------------------------------

Calendar &
Calendar::operator=(const Calendar &right)
{
    if (this != &right) {
        uprv_arrayCopy(right.fFields, fFields, UCAL_FIELD_COUNT);
        uprv_arrayCopy(right.fIsSet, fIsSet, UCAL_FIELD_COUNT);
        uprv_arrayCopy(right.fStamp, fStamp, UCAL_FIELD_COUNT);
        fTime                    = right.fTime;
        fIsTimeSet               = right.fIsTimeSet;
        fAreAllFieldsSet         = right.fAreAllFieldsSet;
        fAreFieldsSet            = right.fAreFieldsSet;
        fAreFieldsVirtuallySet   = right.fAreFieldsVirtuallySet;
        fLenient                 = right.fLenient;
        fRepeatedWallTime        = right.fRepeatedWallTime;
        fSkippedWallTime         = right.fSkippedWallTime;
        delete fZone;
        fZone = nullptr;
        if (right.fZone != nullptr) {
            fZone                = right.fZone->clone();
        }
        fFirstDayOfWeek          = right.fFirstDayOfWeek;
        fMinimalDaysInFirstWeek  = right.fMinimalDaysInFirstWeek;
        fWeekendOnset            = right.fWeekendOnset;
        fWeekendOnsetMillis      = right.fWeekendOnsetMillis;
        fWeekendCease            = right.fWeekendCease;
        fWeekendCeaseMillis      = right.fWeekendCeaseMillis;
        fNextStamp               = right.fNextStamp;
        uprv_strncpy(validLocale, right.validLocale, sizeof(validLocale));
        uprv_strncpy(actualLocale, right.actualLocale, sizeof(actualLocale));
        validLocale[sizeof(validLocale)-1] = 0;
        actualLocale[sizeof(validLocale)-1] = 0;
    }

    return *this;
}

// -------------------------------------

Calendar* U_EXPORT2
Calendar::createInstance(UErrorCode& success)
{
    return createInstance(TimeZone::createDefault(), Locale::getDefault(), success);
}

// -------------------------------------

Calendar* U_EXPORT2
Calendar::createInstance(const TimeZone& zone, UErrorCode& success)
{
    return createInstance(zone, Locale::getDefault(), success);
}

// -------------------------------------

Calendar* U_EXPORT2
Calendar::createInstance(const Locale& aLocale, UErrorCode& success)
{
    return createInstance(TimeZone::forLocaleOrDefault(aLocale), aLocale, success);
}

// ------------------------------------- Adopting

// Note: this is the bottleneck that actually calls the service routines.

Calendar * U_EXPORT2
Calendar::makeInstance(const Locale& aLocale, UErrorCode& success) {
    if (U_FAILURE(success)) {
        return nullptr;
    }

    Locale actualLoc;
    UObject* u = nullptr;

#if !UCONFIG_NO_SERVICE
    if (isCalendarServiceUsed()) {
        u = getCalendarService(success)->get(aLocale, LocaleKey::KIND_ANY, &actualLoc, success);
    }
    else
#endif
    {
        u = createStandardCalendar(getCalendarTypeForLocale(aLocale.getName()), aLocale, success);
    }
    Calendar* c = nullptr;

    if(U_FAILURE(success) || !u) {
        if(U_SUCCESS(success)) { // Propagate some kind of err
            success = U_INTERNAL_PROGRAM_ERROR;
        }
        return nullptr;
    }

#if !UCONFIG_NO_SERVICE
    const UnicodeString* str = dynamic_cast<const UnicodeString*>(u);
    if(str != nullptr) {
        // It's a unicode string telling us what type of calendar to load ("gregorian", etc)
        // Create a Locale over this string
        Locale l("");
        LocaleUtility::initLocaleFromName(*str, l);

#ifdef U_DEBUG_CALSVC
        fprintf(stderr, "Calendar::createInstance(%s), looking up [%s]\n", aLocale.getName(), l.getName());
#endif

        Locale actualLoc2;
        delete u;
        u = nullptr;

        // Don't overwrite actualLoc, since the actual loc from this call
        // may be something like "@calendar=gregorian" -- TODO investigate
        // further...
        c = (Calendar*)getCalendarService(success)->get(l, LocaleKey::KIND_ANY, &actualLoc2, success);

        if(U_FAILURE(success) || !c) {
            if(U_SUCCESS(success)) {
                success = U_INTERNAL_PROGRAM_ERROR; // Propagate some err
            }
            return nullptr;
        }

        str = dynamic_cast<const UnicodeString*>(c);
        if(str != nullptr) {
            // recursed! Second lookup returned a UnicodeString.
            // Perhaps DefaultCalendar{} was set to another locale.
#ifdef U_DEBUG_CALSVC
            char tmp[200];
            // Extract a char* out of it..
            int32_t len = str->length();
            int32_t actLen = sizeof(tmp)-1;
            if(len > actLen) {
                len = actLen;
            }
            str->extract(0,len,tmp);
            tmp[len]=0;

            fprintf(stderr, "err - recursed, 2nd lookup was unistring %s\n", tmp);
#endif
            success = U_MISSING_RESOURCE_ERROR;  // requested a calendar type which could NOT be found.
            delete c;
            return nullptr;
        }
#ifdef U_DEBUG_CALSVC
        fprintf(stderr, "%p: setting week count data to locale %s, actual locale %s\n", c, (const char*)aLocale.getName(), (const char *)actualLoc.getName());
#endif
        c->setWeekData(aLocale, c->getType(), success);  // set the correct locale (this was an indirect calendar)

        char keyword[ULOC_FULLNAME_CAPACITY] = "";
        UErrorCode tmpStatus = U_ZERO_ERROR;
        l.getKeywordValue("calendar", keyword, ULOC_FULLNAME_CAPACITY, tmpStatus);
        if (U_SUCCESS(tmpStatus) && uprv_strcmp(keyword, "iso8601") == 0) {
            c->setFirstDayOfWeek(UCAL_MONDAY);
            c->setMinimalDaysInFirstWeek(4);
        }
    }
    else
#endif /* UCONFIG_NO_SERVICE */
    {
        // a calendar was returned - we assume the factory did the right thing.
        c = (Calendar*)u;
    }

    return c;
}

Calendar* U_EXPORT2
Calendar::createInstance(TimeZone* zone, const Locale& aLocale, UErrorCode& success)
{
    LocalPointer<TimeZone> zonePtr(zone);
    const SharedCalendar *shared = nullptr;
    UnifiedCache::getByLocale(aLocale, shared, success);
    if (U_FAILURE(success)) {
        return nullptr;
    }
    Calendar *c = (*shared)->clone();
    shared->removeRef();
    if (c == nullptr) {
        success = U_MEMORY_ALLOCATION_ERROR;
        return nullptr;
    }

    // Now, reset calendar to default state:
    c->adoptTimeZone(zonePtr.orphan()); //  Set the correct time zone
    c->setTimeInMillis(getNow(), success); // let the new calendar have the current time.

    return c;
}

// -------------------------------------

Calendar* U_EXPORT2
Calendar::createInstance(const TimeZone& zone, const Locale& aLocale, UErrorCode& success)
{
    Calendar* c = createInstance(aLocale, success);
    if(U_SUCCESS(success) && c) {
        c->setTimeZone(zone);
    }
    return c;
}

// -------------------------------------

void U_EXPORT2
Calendar::getCalendarTypeFromLocale(
        const Locale &aLocale,
        char *typeBuffer,
        int32_t typeBufferSize,
        UErrorCode &success) {
    const SharedCalendar *shared = nullptr;
    UnifiedCache::getByLocale(aLocale, shared, success);
    if (U_FAILURE(success)) {
        return;
    }
    uprv_strncpy(typeBuffer, (*shared)->getType(), typeBufferSize);
    shared->removeRef();
    if (typeBuffer[typeBufferSize - 1]) {
        success = U_BUFFER_OVERFLOW_ERROR;
    }
}

bool
Calendar::operator==(const Calendar& that) const
{
    UErrorCode status = U_ZERO_ERROR;
    return isEquivalentTo(that) &&
        getTimeInMillis(status) == that.getTimeInMillis(status) &&
        U_SUCCESS(status);
}

UBool
Calendar::isEquivalentTo(const Calendar& other) const
{
    return typeid(*this) == typeid(other) &&
        fLenient                == other.fLenient &&
        fRepeatedWallTime       == other.fRepeatedWallTime &&
        fSkippedWallTime        == other.fSkippedWallTime &&
        fFirstDayOfWeek         == other.fFirstDayOfWeek &&
        fMinimalDaysInFirstWeek == other.fMinimalDaysInFirstWeek &&
        fWeekendOnset           == other.fWeekendOnset &&
        fWeekendOnsetMillis     == other.fWeekendOnsetMillis &&
        fWeekendCease           == other.fWeekendCease &&
        fWeekendCeaseMillis     == other.fWeekendCeaseMillis &&
        *fZone                  == *other.fZone;
}

// -------------------------------------

UBool
Calendar::equals(const Calendar& when, UErrorCode& status) const
{
    return (this == &when ||
        getTime(status) == when.getTime(status));
}

// -------------------------------------

UBool
Calendar::before(const Calendar& when, UErrorCode& status) const
{
    return (this != &when &&
        getTimeInMillis(status) < when.getTimeInMillis(status));
}

// -------------------------------------

UBool
Calendar::after(const Calendar& when, UErrorCode& status) const
{
    return (this != &when &&
        getTimeInMillis(status) > when.getTimeInMillis(status));
}

// -------------------------------------


const Locale* U_EXPORT2
Calendar::getAvailableLocales(int32_t& count)
{
    return Locale::getAvailableLocales(count);
}

// -------------------------------------

StringEnumeration* U_EXPORT2
Calendar::getKeywordValuesForLocale(const char* key,
                    const Locale& locale, UBool commonlyUsed, UErrorCode& status)
{
    // This is a wrapper over ucal_getKeywordValuesForLocale
    UEnumeration *uenum = ucal_getKeywordValuesForLocale(key, locale.getName(),
                                                        commonlyUsed, &status);
    if (U_FAILURE(status)) {
        uenum_close(uenum);
        return nullptr;
    }
    UStringEnumeration* ustringenum = new UStringEnumeration(uenum);
    if (ustringenum == nullptr) {
        status = U_MEMORY_ALLOCATION_ERROR;
    }
    return ustringenum;
}

// -------------------------------------

UDate U_EXPORT2
Calendar::getNow()
{
    return uprv_getUTCtime(); // return as milliseconds
}

// -------------------------------------

/**
* Gets this Calendar's current time as a long.
* @return the current time as UTC milliseconds from the epoch.
*/
double
Calendar::getTimeInMillis(UErrorCode& status) const
{
    if(U_FAILURE(status))
        return 0.0;

    if ( ! fIsTimeSet)
        ((Calendar*)this)->updateTime(status);

    /* Test for buffer overflows */
    if(U_FAILURE(status)) {
        return 0.0;
    }
    return fTime;
}

// -------------------------------------

/**
* Sets this Calendar's current time from the given long value.
* A status of U_ILLEGAL_ARGUMENT_ERROR is set when millis is
* outside the range permitted by a Calendar object when not in lenient mode.
* when in lenient mode the out of range values are pinned to their respective min/max.
* @param date the new time in UTC milliseconds from the epoch.
*/
void
Calendar::setTimeInMillis( double millis, UErrorCode& status ) {
    if(U_FAILURE(status))
        return;

    if (millis > MAX_MILLIS) {
        if(isLenient()) {
            millis = MAX_MILLIS;
        } else {
		    status = U_ILLEGAL_ARGUMENT_ERROR;
		    return;
        }
    } else if (millis < MIN_MILLIS) {
        if(isLenient()) {
            millis = MIN_MILLIS;
        } else {
    		status = U_ILLEGAL_ARGUMENT_ERROR;
	    	return;
        }
    } else if (uprv_isNaN(millis)) {
        status = U_ILLEGAL_ARGUMENT_ERROR;
        return;
    }

    fTime = millis;
    fAreFieldsSet = fAreAllFieldsSet = false;
    fIsTimeSet = fAreFieldsVirtuallySet = true;

    for (int32_t i=0; i<UCAL_FIELD_COUNT; ++i) {
        fFields[i]     = 0;
        fStamp[i]     = kUnset;
        fIsSet[i]     = false;
    }


}

// -------------------------------------

int32_t
Calendar::get(UCalendarDateFields field, UErrorCode& status) const
{
    if (U_FAILURE(status)) {
        return 0;
    }
    if (field < 0 || field >= UCAL_FIELD_COUNT) {
        status = U_ILLEGAL_ARGUMENT_ERROR;
        return 0;
    }
    // field values are only computed when actually requested; for more on when computation
    // of various things happens, see the "data flow in Calendar" description at the top
    // of this file
    if (U_SUCCESS(status)) ((Calendar*)this)->complete(status); // Cast away const
    return U_SUCCESS(status) ? fFields[field] : 0;
}

// -------------------------------------

void
Calendar::set(UCalendarDateFields field, int32_t value)
{
    if (field < 0 || field >= UCAL_FIELD_COUNT) {
        return;
    }
    if (fAreFieldsVirtuallySet) {
        UErrorCode ec = U_ZERO_ERROR;
        computeFields(ec);
    }
    fFields[field]     = value;
    /* Ensure that the fNextStamp value doesn't go pass max value for int32_t */
    if (fNextStamp == STAMP_MAX) {
        recalculateStamp();
    }
    fStamp[field]     = fNextStamp++;
    fIsSet[field]     = true; // Remove later
    fIsTimeSet = fAreFieldsSet = fAreFieldsVirtuallySet = false;
}

// -------------------------------------

void
Calendar::set(int32_t year, int32_t month, int32_t date)
{
    set(UCAL_YEAR, year);
    set(UCAL_MONTH, month);
    set(UCAL_DATE, date);
}

// -------------------------------------

void
Calendar::set(int32_t year, int32_t month, int32_t date, int32_t hour, int32_t minute)
{
    set(UCAL_YEAR, year);
    set(UCAL_MONTH, month);
    set(UCAL_DATE, date);
    set(UCAL_HOUR_OF_DAY, hour);
    set(UCAL_MINUTE, minute);
}

// -------------------------------------

void
Calendar::set(int32_t year, int32_t month, int32_t date, int32_t hour, int32_t minute, int32_t second)
{
    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);
}

// -------------------------------------
int32_t Calendar::getRelatedYear(UErrorCode &status) const
{
    return get(UCAL_EXTENDED_YEAR, status);
}

// -------------------------------------
void Calendar::setRelatedYear(int32_t year)
{
    // set extended year
    set(UCAL_EXTENDED_YEAR, year);
}

// -------------------------------------

void
Calendar::clear()
{
    for (int32_t i=0; i<UCAL_FIELD_COUNT; ++i) {
        fFields[i]     = 0; // Must do this; other code depends on it
        fStamp[i]     = kUnset;
        fIsSet[i]     = false; // Remove later
    }
    fIsTimeSet = fAreFieldsSet = fAreAllFieldsSet = fAreFieldsVirtuallySet = false;
    // fTime is not 'cleared' - may be used if no fields are set.
}

// -------------------------------------

void
Calendar::clear(UCalendarDateFields field)
{
    if (field < 0 || field >= UCAL_FIELD_COUNT) {
        return;
    }
    if (fAreFieldsVirtuallySet) {
        UErrorCode ec = U_ZERO_ERROR;
        computeFields(ec);
    }
    fFields[field]         = 0;
    fStamp[field]         = kUnset;
    if (field == UCAL_MONTH) {
        fFields[UCAL_ORDINAL_MONTH]         = 0;
        fStamp[UCAL_ORDINAL_MONTH]         = kUnset;
        fIsSet[UCAL_ORDINAL_MONTH]         = false; // Remove later
    }
    if (field == UCAL_ORDINAL_MONTH) {
        fFields[UCAL_MONTH]         = 0;
        fStamp[UCAL_MONTH]         = kUnset;
        fIsSet[UCAL_MONTH]         = false; // Remove later
    }
    fIsTimeSet = fAreFieldsSet = fAreAllFieldsSet = fAreFieldsVirtuallySet = false;
}

// -------------------------------------

UBool
Calendar::isSet(UCalendarDateFields field) const
{
    if (field < 0 || field >= UCAL_FIELD_COUNT) {
        return false;
    }
    return fAreFieldsVirtuallySet || (fStamp[field] != kUnset);
}


int32_t Calendar::newestStamp(UCalendarDateFields first, UCalendarDateFields last, int32_t bestStampSoFar) const
{
    int32_t bestStamp = bestStampSoFar;
    for (int32_t i=(int32_t)first; i<=(int32_t)last; ++i) {
        if (fStamp[i] > bestStamp) {
            bestStamp = fStamp[i];
        }
    }
    return bestStamp;
}


// -------------------------------------

void
Calendar::complete(UErrorCode& status)
{
    if (U_FAILURE(status)) {
       return;
    }
    if (!fIsTimeSet) {
        updateTime(status);
        /* Test for buffer overflows */
        if(U_FAILURE(status)) {
            return;
        }
    }
    if (!fAreFieldsSet) {
        computeFields(status); // fills in unset fields
        /* Test for buffer overflows */
        if(U_FAILURE(status)) {
            return;
        }
        fAreFieldsSet         = true;
        fAreAllFieldsSet     = true;
    }
}

//-------------------------------------------------------------------------
// Protected utility methods for use by subclasses.  These are very handy
// for implementing add, roll, and computeFields.
//-------------------------------------------------------------------------

/**
* Adjust the specified field so that it is within
* the allowable range for the date to which this calendar is set.
* For example, in a Gregorian calendar pinning the {@link #DAY_OF_MONTH DAY_OF_MONTH}
* field for a calendar set to April 31 would cause it to be set
* to April 30.
* <p>
* <b>Subclassing:</b>
* <br>
* This utility method is intended for use by subclasses that need to implement
* their own overrides of {@link #roll roll} and {@link #add add}.
* <p>
* <b>Note:</b>
* <code>pinField</code> is implemented in terms of
* {@link #getActualMinimum getActualMinimum}
* and {@link #getActualMaximum getActualMaximum}.  If either of those methods uses
* a slow, iterative algorithm for a particular field, it would be
* unwise to attempt to call <code>pinField</code> for that field.  If you
* really do need to do so, you should override this method to do
* something more efficient for that field.
* <p>
* @param field The calendar field whose value should be pinned.
*
* @see #getActualMinimum
* @see #getActualMaximum
* @stable ICU 2.0
*/
void Calendar::pinField(UCalendarDateFields field, UErrorCode& status) {
    if (U_FAILURE(status)) {
       return;
    }
    if (field < 0 || field >= UCAL_FIELD_COUNT) {
       status = U_ILLEGAL_ARGUMENT_ERROR;
       return;
    }
    int32_t max = getActualMaximum(field, status);
    int32_t min = getActualMinimum(field, status);

    if (fFields[field] > max) {
        set(field, max);
    } else if (fFields[field] < min) {
        set(field, min);
    }
}


void Calendar::computeFields(UErrorCode &ec)
{
    if (U_FAILURE(ec)) {
        return;
    }
    // Compute local wall millis
    double localMillis = internalGetTime();
    int32_t rawOffset, dstOffset;
    getTimeZone().getOffset(localMillis, false, rawOffset, dstOffset, ec);
    if (U_FAILURE(ec)) {
        return;
    }
    localMillis += (rawOffset + dstOffset);

    // Mark fields as set.  Do this before calling handleComputeFields().
    uint32_t mask =   //fInternalSetMask;
        (1 << UCAL_ERA) |
        (1 << UCAL_YEAR) |
        (1 << UCAL_MONTH) |
        (1 << UCAL_DAY_OF_MONTH) | // = UCAL_DATE
        (1 << UCAL_DAY_OF_YEAR) |
        (1 << UCAL_EXTENDED_YEAR) |
        (1 << UCAL_ORDINAL_MONTH);

    for (int32_t i=0; i<UCAL_FIELD_COUNT; ++i) {
        if ((mask & 1) == 0) {
            fStamp[i] = kInternallySet;
            fIsSet[i] = true; // Remove later
        } else {
            fStamp[i] = kUnset;
            fIsSet[i] = false; // Remove later
        }
        mask >>= 1;
    }

    // We used to check for and correct extreme millis values (near
    // Long.MIN_VALUE or Long.MAX_VALUE) here.  Such values would cause
    // overflows from positive to negative (or vice versa) and had to
    // be manually tweaked.  We no longer need to do this because we
    // have limited the range of supported dates to those that have a
    // Julian day that fits into an int.  This allows us to implement a
    // JULIAN_DAY field and also removes some inelegant code. - Liu
    // 11/6/00

    int32_t millisInDay;
    int32_t days = ClockMath::floorDivide(localMillis, kOneDay, &millisInDay);

    internalSet(UCAL_JULIAN_DAY,days + kEpochStartAsJulianDay);

#if defined (U_DEBUG_CAL)
    //fprintf(stderr, "%s:%d- Hmm! Jules @ %d, as per %.0lf millis\n",
    //__FILE__, __LINE__, fFields[UCAL_JULIAN_DAY], localMillis);
#endif

    computeGregorianAndDOWFields(fFields[UCAL_JULIAN_DAY], ec);

    // Call framework method to have subclass compute its fields.
    // These must include, at a minimum, MONTH, DAY_OF_MONTH,
    // EXTENDED_YEAR, YEAR, DAY_OF_YEAR.  This method will call internalSet(),
    // which will update stamp[].
    handleComputeFields(fFields[UCAL_JULIAN_DAY], ec);

    // Compute week-related fields, based on the subclass-computed
    // fields computed by handleComputeFields().
    computeWeekFields(ec);

    // Compute time-related fields.  These are independent of the date and
    // of the subclass algorithm.  They depend only on the local zone
    // wall milliseconds in day.
    if (U_FAILURE(ec)) {
        return;
    }

    fFields[UCAL_MILLISECONDS_IN_DAY] = millisInDay;
    U_ASSERT(getMinimum(UCAL_MILLISECONDS_IN_DAY) <=
             fFields[UCAL_MILLISECONDS_IN_DAY]);
    U_ASSERT(fFields[UCAL_MILLISECONDS_IN_DAY] <=
             getMaximum(UCAL_MILLISECONDS_IN_DAY));

    fFields[UCAL_MILLISECOND] = millisInDay % 1000;
    U_ASSERT(getMinimum(UCAL_MILLISECOND) <= fFields[UCAL_MILLISECOND]);
    U_ASSERT(fFields[UCAL_MILLISECOND] <= getMaximum(UCAL_MILLISECOND));

    millisInDay /= 1000;
    fFields[UCAL_SECOND] = millisInDay % 60;
    U_ASSERT(getMinimum(UCAL_SECOND) <= fFields[UCAL_SECOND]);
    U_ASSERT(fFields[UCAL_SECOND] <= getMaximum(UCAL_SECOND));

    millisInDay /= 60;
    fFields[UCAL_MINUTE] = millisInDay % 60;
    U_ASSERT(getMinimum(UCAL_MINUTE) <= fFields[UCAL_MINUTE]);
    U_ASSERT(fFields[UCAL_MINUTE] <= getMaximum(UCAL_MINUTE));

    millisInDay /= 60;
    fFields[UCAL_HOUR_OF_DAY] = millisInDay;
    U_ASSERT(getMinimum(UCAL_HOUR_OF_DAY) <= fFields[UCAL_HOUR_OF_DAY]);
    U_ASSERT(fFields[UCAL_HOUR_OF_DAY] <= getMaximum(UCAL_HOUR_OF_DAY));

    fFields[UCAL_AM_PM] = millisInDay / 12; // Assume AM == 0
    U_ASSERT(getMinimum(UCAL_AM_PM) <= fFields[UCAL_AM_PM]);
    U_ASSERT(fFields[UCAL_AM_PM] <= getMaximum(UCAL_AM_PM));

    fFields[UCAL_HOUR] = millisInDay % 12;
    U_ASSERT(getMinimum(UCAL_HOUR) <= fFields[UCAL_HOUR]);
    U_ASSERT(fFields[UCAL_HOUR] <= getMaximum(UCAL_HOUR));

    fFields[UCAL_ZONE_OFFSET] = rawOffset;
    U_ASSERT(getMinimum(UCAL_ZONE_OFFSET) <= fFields[UCAL_ZONE_OFFSET]);
    U_ASSERT(fFields[UCAL_ZONE_OFFSET] <= getMaximum(UCAL_ZONE_OFFSET));

    fFields[UCAL_DST_OFFSET] = dstOffset;
    U_ASSERT(getMinimum(UCAL_DST_OFFSET) <= fFields[UCAL_DST_OFFSET]);
    U_ASSERT(fFields[UCAL_DST_OFFSET] <= getMaximum(UCAL_DST_OFFSET));
}

uint8_t Calendar::julianDayToDayOfWeek(double julian)
{
    // If julian is negative, then julian%7 will be negative, so we adjust
    // accordingly.  We add 1 because Julian day 0 is Monday.
    int8_t dayOfWeek = (int8_t) uprv_fmod(julian + 1, 7);

    uint8_t result = (uint8_t)(dayOfWeek + ((dayOfWeek < 0) ? (7+UCAL_SUNDAY ) : UCAL_SUNDAY));
    return result;
}

/**
* Compute the Gregorian calendar year, month, and day of month from
* the given Julian day.  These values are not stored in fields, but in
* member variables gregorianXxx.  Also compute the DAY_OF_WEEK and
* DOW_LOCAL fields.
*/
void Calendar::computeGregorianAndDOWFields(int32_t julianDay, UErrorCode &ec)
{
    computeGregorianFields(julianDay, ec);
    if (U_FAILURE(ec)) {
        return;
    }

    // Compute day of week: JD 0 = Monday
    int32_t dow = julianDayToDayOfWeek(julianDay);
    internalSet(UCAL_DAY_OF_WEEK,dow);

    // Calculate 1-based localized day of week
    int32_t dowLocal = dow - getFirstDayOfWeek() + 1;
    if (dowLocal < 1) {
        dowLocal += 7;
    }
    internalSet(UCAL_DOW_LOCAL,dowLocal);
    fFields[UCAL_DOW_LOCAL] = dowLocal;
}

/**
* Compute the Gregorian calendar year, month, and day of month from the
* Julian day.  These values are not stored in fields, but in member
* variables gregorianXxx.  They are used for time zone computations and by
* subclasses that are Gregorian derivatives.  Subclasses may call this
* method to perform a Gregorian calendar millis->fields computation.
*/
void Calendar::computeGregorianFields(int32_t julianDay, UErrorCode& ec) {
    if (U_FAILURE(ec)) {
        return;
    }
    int32_t gregorianDayOfWeekUnused;
    Grego::dayToFields(julianDay - kEpochStartAsJulianDay, fGregorianYear, fGregorianMonth, fGregorianDayOfMonth, gregorianDayOfWeekUnused, fGregorianDayOfYear);
}

/**
* Compute the fields WEEK_OF_YEAR, YEAR_WOY, WEEK_OF_MONTH,
* DAY_OF_WEEK_IN_MONTH, and DOW_LOCAL from EXTENDED_YEAR, YEAR,
* DAY_OF_WEEK, and DAY_OF_YEAR.  The latter fields are computed by the
* subclass based on the calendar system.
*
* <p>The YEAR_WOY field is computed simplistically.  It is equal to YEAR
* most of the time, but at the year boundary it may be adjusted to YEAR-1
* or YEAR+1 to reflect the overlap of a week into an adjacent year.  In
* this case, a simple increment or decrement is performed on YEAR, even
* though this may yield an invalid YEAR value.  For instance, if the YEAR
* is part of a calendar system with an N-year cycle field CYCLE, then
* incrementing the YEAR may involve incrementing CYCLE and setting YEAR
* back to 0 or 1.  This is not handled by this code, and in fact cannot be
* simply handled without having subclasses define an entire parallel set of
* fields for fields larger than or equal to a year.  This additional
* complexity is not warranted, since the intention of the YEAR_WOY field is
* to support ISO 8601 notation, so it will typically be used with a
* proleptic Gregorian calendar, which has no field larger than a year.
*/
void Calendar::computeWeekFields(UErrorCode &ec) {
    if(U_FAILURE(ec)) {
        return;
    }
    int32_t eyear = fFields[UCAL_EXTENDED_YEAR];
    int32_t dayOfWeek = fFields[UCAL_DAY_OF_WEEK];
    int32_t dayOfYear = fFields[UCAL_DAY_OF_YEAR];

    // WEEK_OF_YEAR start
    // Compute the week of the year.  For the Gregorian calendar, valid week
    // numbers run from 1 to 52 or 53, depending on the year, the first day
    // of the week, and the minimal days in the first week.  For other
    // calendars, the valid range may be different -- it depends on the year
    // length.  Days at the start of the year may fall into the last week of
    // the previous year; days at the end of the year may fall into the
    // first week of the next year.  ASSUME that the year length is less than
    // 7000 days.
    int32_t yearOfWeekOfYear = eyear;
    int32_t relDow = (dayOfWeek + 7 - getFirstDayOfWeek()) % 7; // 0..6
    int32_t relDowJan1 = (dayOfWeek - dayOfYear + 7001 - getFirstDayOfWeek()) % 7; // 0..6
    int32_t woy = (dayOfYear - 1 + relDowJan1) / 7; // 0..53
    if ((7 - relDowJan1) >= getMinimalDaysInFirstWeek()) {
        ++woy;
    }

    // Adjust for weeks at the year end that overlap into the previous or
    // next calendar year.
    if (woy == 0) {
        // We are the last week of the previous year.
        // Check to see if we are in the last week; if so, we need
        // to handle the case in which we are the first week of the
        // next year.

        int32_t prevDoy = dayOfYear + handleGetYearLength(eyear - 1);
        woy = weekNumber(prevDoy, dayOfWeek);
        yearOfWeekOfYear--;
    } else {
        int32_t lastDoy = handleGetYearLength(eyear);
        // Fast check: For it to be week 1 of the next year, the DOY
        // must be on or after L-5, where L is yearLength(), then it
        // cannot possibly be week 1 of the next year:
        //          L-5                  L
        // doy: 359 360 361 362 363 364 365 001
        // dow:      1   2   3   4   5   6   7
        if (dayOfYear >= (lastDoy - 5)) {
            int32_t lastRelDow = (relDow + lastDoy - dayOfYear) % 7;
            if (lastRelDow < 0) {
                lastRelDow += 7;
            }
            if (((6 - lastRelDow) >= getMinimalDaysInFirstWeek()) &&
                ((dayOfYear + 7 - relDow) > lastDoy)) {
                    woy = 1;
                    yearOfWeekOfYear++;
                }
        }
    }
    fFields[UCAL_WEEK_OF_YEAR] = woy;
    fFields[UCAL_YEAR_WOY] = yearOfWeekOfYear;
    // min/max of years are not constrains for caller, so not assert here.
    // WEEK_OF_YEAR end

    int32_t dayOfMonth = fFields[UCAL_DAY_OF_MONTH];
    fFields[UCAL_WEEK_OF_MONTH] = weekNumber(dayOfMonth, dayOfWeek);
    U_ASSERT(getMinimum(UCAL_WEEK_OF_MONTH) <= fFields[UCAL_WEEK_OF_MONTH]);
    U_ASSERT(fFields[UCAL_WEEK_OF_MONTH] <= getMaximum(UCAL_WEEK_OF_MONTH));

    fFields[UCAL_DAY_OF_WEEK_IN_MONTH] = (dayOfMonth-1) / 7 + 1;
    U_ASSERT(getMinimum(UCAL_DAY_OF_WEEK_IN_MONTH) <=
             fFields[UCAL_DAY_OF_WEEK_IN_MONTH]);
    U_ASSERT(fFields[UCAL_DAY_OF_WEEK_IN_MONTH] <=
             getMaximum(UCAL_DAY_OF_WEEK_IN_MONTH));

#if defined (U_DEBUG_CAL)
    if(fFields[UCAL_DAY_OF_WEEK_IN_MONTH]==0) fprintf(stderr, "%s:%d: DOWIM %d on %g\n",
        __FILE__, __LINE__,fFields[UCAL_DAY_OF_WEEK_IN_MONTH], fTime);
#endif
}


int32_t Calendar::weekNumber(int32_t desiredDay, int32_t dayOfPeriod, int32_t dayOfWeek)
{
    // Determine the day of the week of the first day of the period
    // in question (either a year or a month).  Zero represents the
    // first day of the week on this calendar.
    int32_t periodStartDayOfWeek = (dayOfWeek - getFirstDayOfWeek() - dayOfPeriod + 1) % 7;
    if (periodStartDayOfWeek < 0) periodStartDayOfWeek += 7;

    // Compute the week number.  Initially, ignore the first week, which
    // may be fractional (or may not be).  We add periodStartDayOfWeek in
    // order to fill out the first week, if it is fractional.
    int32_t weekNo = (desiredDay + periodStartDayOfWeek - 1)/7;

    // If the first week is long enough, then count it.  If
    // the minimal days in the first week is one, or if the period start
    // is zero, we always increment weekNo.
    if ((7 - periodStartDayOfWeek) >= getMinimalDaysInFirstWeek()) ++weekNo;

    return weekNo;
}

void Calendar::handleComputeFields(int32_t /* julianDay */, UErrorCode& status)
{
    if (U_FAILURE(status)) {
        return;
    }
    int32_t month = getGregorianMonth();
    internalSet(UCAL_MONTH, month);
    internalSet(UCAL_ORDINAL_MONTH, month);
    internalSet(UCAL_DAY_OF_MONTH, getGregorianDayOfMonth());
    internalSet(UCAL_DAY_OF_YEAR, getGregorianDayOfYear());
    int32_t eyear = getGregorianYear();
    internalSet(UCAL_EXTENDED_YEAR, eyear);
    int32_t era = GregorianCalendar::AD;
    if (eyear < 1) {
        era = GregorianCalendar::BC;
        eyear = 1 - eyear;
    }
    internalSet(UCAL_ERA, era);
    internalSet(UCAL_YEAR, eyear);
}
// -------------------------------------


void Calendar::roll(EDateFields field, int32_t amount, UErrorCode& status)
{
    roll((UCalendarDateFields)field, amount, status);
}

void Calendar::roll(UCalendarDateFields field, int32_t amount, UErrorCode& status) UPRV_NO_SANITIZE_UNDEFINED {
    if (amount == 0) {
        return; // Nothing to do
    }

    complete(status);

    if(U_FAILURE(status)) {
        return;
    }
    if (field < 0 || field >= UCAL_FIELD_COUNT) {
       status = U_ILLEGAL_ARGUMENT_ERROR;
       return;
    }
    switch (field) {
    case UCAL_DAY_OF_MONTH:
    case UCAL_AM_PM:
    case UCAL_MINUTE:
    case UCAL_SECOND:
    case UCAL_MILLISECOND:
    case UCAL_MILLISECONDS_IN_DAY:
    case UCAL_ERA:
        // These are the standard roll instructions.  These work for all
        // simple cases, that is, cases in which the limits are fixed, such
        // as the hour, the day of the month, and the era.
        {
            int32_t min = getActualMinimum(field,status);
            int32_t max = getActualMaximum(field,status);
            int32_t gap = max - min + 1;

            int32_t value = internalGet(field) + amount;
            value = (value - min) % gap;
            if (value < 0) {
                value += gap;
            }
            value += min;

            set(field, value);
            return;
        }

    case UCAL_HOUR:
    case UCAL_HOUR_OF_DAY:
        // Rolling the hour is difficult on the ONSET and CEASE days of
        // daylight savings.  For example, if the change occurs at
        // 2 AM, we have the following progression:
        // ONSET: 12 Std -> 1 Std -> 3 Dst -> 4 Dst
        // CEASE: 12 Dst -> 1 Dst -> 1 Std -> 2 Std
        // To get around this problem we don't use fields; we manipulate
        // the time in millis directly.
        {
            // Assume min == 0 in calculations below
            double start = getTimeInMillis(status);
            int32_t oldHour = internalGet(field);
            int32_t max = getMaximum(field);
            int32_t newHour = (oldHour + amount) % (max + 1);
            if (newHour < 0) {
                newHour += max + 1;
            }
            setTimeInMillis(start + kOneHour * (newHour - oldHour),status);
            return;
        }

    case UCAL_MONTH:
    case UCAL_ORDINAL_MONTH:
        // Rolling the month involves both pinning the final value
        // and adjusting the DAY_OF_MONTH if necessary.  We only adjust the
        // DAY_OF_MONTH if, after updating the MONTH field, it is illegal.
        // E.g., <jan31>.roll(MONTH, 1) -> <feb28> or <feb29>.
        {
            int32_t max = getActualMaximum(UCAL_MONTH, status);
            int32_t mon = (internalGet(UCAL_MONTH) + amount) % (max+1);

            if (mon < 0) {
                mon += (max + 1);
            }
            set(UCAL_MONTH, mon);

            // Keep the day of month in range.  We don't want to spill over
            // into the next month; e.g., we don't want jan31 + 1 mo -> feb31 ->
            // mar3.
            pinField(UCAL_DAY_OF_MONTH,status);
            return;
        }

    case UCAL_YEAR:
    case UCAL_YEAR_WOY:
        {
            // * If era==0 and years go backwards in time, change sign of amount.
            // * Until we have new API per #9393, we temporarily hardcode knowledge of
            //   which calendars have era 0 years that go backwards.
            UBool era0WithYearsThatGoBackwards = false;
            int32_t era = get(UCAL_ERA, status);
            if (era == 0) {
                const char * calType = getType();
                if ( uprv_strcmp(calType,"gregorian")==0 || uprv_strcmp(calType,"roc")==0 || uprv_strcmp(calType,"coptic")==0 ) {
                    amount = -amount;
                    era0WithYearsThatGoBackwards = true;
                }
            }
            int32_t newYear = internalGet(field) + amount;
            if (era > 0 || newYear >= 1) {
                int32_t maxYear = getActualMaximum(field, status);
                if (maxYear < 32768) {
                    // this era has real bounds, roll should wrap years
                    if (newYear < 1) {
                        newYear = maxYear - ((-newYear) % maxYear);
                    } else if (newYear > maxYear) {
                        newYear = ((newYear - 1) % maxYear) + 1;
                    }
                // else era is unbounded, just pin low year instead of wrapping
                } else if (newYear < 1) {
                    newYear = 1;
                }
            // else we are in era 0 with newYear < 1;
            // calendars with years that go backwards must pin the year value at 0,
            // other calendars can have years < 0 in era 0
            } else if (era0WithYearsThatGoBackwards) {
                newYear = 1;
            }
            set(field, newYear);
            pinField(UCAL_MONTH,status);
            pinField(UCAL_DAY_OF_MONTH,status);
            return;
        }

    case UCAL_EXTENDED_YEAR:
        // Rolling the year can involve pinning the DAY_OF_MONTH.
        set(field, internalGet(field) + amount);
        pinField(UCAL_MONTH,status);
        pinField(UCAL_DAY_OF_MONTH,status);
        return;

    case UCAL_WEEK_OF_MONTH:
        {
            // 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?

            // 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 the week (normalized for locale) for the first
            // of the month.
            int32_t fdm = (dow - internalGet(UCAL_DAY_OF_MONTH) + 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 = getActualMaximum(UCAL_DAY_OF_MONTH, status);
            int32_t ldm = (monthLen - internalGet(UCAL_DAY_OF_MONTH) + 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 day_of_month = (internalGet(UCAL_DAY_OF_MONTH) + amount*7 -
                start) % gap;
            if (day_of_month < 0) day_of_month += gap;
            day_of_month += start;

            // Finally, pin to the real start and end of the month.
            if (day_of_month < 1) day_of_month = 1;
            if (day_of_month > monthLen) day_of_month = 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.
            set(UCAL_DAY_OF_MONTH, day_of_month);
            return;
        }
    case UCAL_WEEK_OF_YEAR:
        {
            // This follows the outline of WEEK_OF_MONTH, except it applies
            // to the whole year.  Please see the comment for WEEK_OF_MONTH
            // for general notes.

            // 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 the week (normalized for locale) for the first
            // of the year.
            int32_t fdy = (dow - internalGet(UCAL_DAY_OF_YEAR) + 1) % 7;
            if (fdy < 0) fdy += 7;

            // Get the first day of the first full week of the year,
            // 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 - fdy) < getMinimalDaysInFirstWeek())
                start = 8 - fdy; // Skip the first partial week
            else
                start = 1 - fdy; // This may be zero or negative

            // Get the day of the week (normalized for locale) for the last
            // day of the year.
            int32_t yearLen = getActualMaximum(UCAL_DAY_OF_YEAR,status);
            int32_t ldy = (yearLen - internalGet(UCAL_DAY_OF_YEAR) + dow) % 7;
            // We know yearLen >= DAY_OF_YEAR so we skip the += 7 step here.

            // Get the limit day for the blocked-off rectangular year; that
            // is, the day which is one past the last day of the year,
            // after the year 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 = yearLen + 7 - ldy;

            // Now roll between start and (limit - 1).
            int32_t gap = limit - start;
            int32_t day_of_year = (internalGet(UCAL_DAY_OF_YEAR) + amount*7 -
                start) % gap;
            if (day_of_year < 0) day_of_year += gap;
            day_of_year += start;

            // Finally, pin to the real start and end of the month.
            if (day_of_year < 1) day_of_year = 1;
            if (day_of_year > yearLen) day_of_year = yearLen;

            // Make sure that the year and day of year are attended to by
            // clearing other fields which would normally take precedence.
            // If the disambiguation algorithm is changed, this section will
            // have to be updated as well.
            set(UCAL_DAY_OF_YEAR, day_of_year);
            clear(UCAL_MONTH);
            clear(UCAL_ORDINAL_MONTH);
            return;
        }
    case UCAL_DAY_OF_YEAR:
        {
            // Roll the day of year using millis.  Compute the millis for
            // the start of the year, and get the length of the year.
            double delta = amount * kOneDay; // Scale up from days to millis
            double min2 = internalGet(UCAL_DAY_OF_YEAR)-1;
            min2 *= kOneDay;
            min2 = internalGetTime() - min2;

            //      double min2 = internalGetTime() - (internalGet(UCAL_DAY_OF_YEAR) - 1.0) * kOneDay;
            double newtime;

            double yearLength = getActualMaximum(UCAL_DAY_OF_YEAR,status);
            double oneYear = yearLength;
            oneYear *= kOneDay;
            newtime = uprv_fmod((internalGetTime() + delta - min2), oneYear);
            if (newtime < 0) newtime += oneYear;
            setTimeInMillis(newtime + min2, status);
            return;
        }
    case UCAL_DAY_OF_WEEK:
    case UCAL_DOW_LOCAL:
        {
            // Roll the day of week using millis.  Compute the millis for
            // the start of the week, using the first day of week setting.
            // Restrict the millis to [start, start+7days).
            double delta = amount * kOneDay; // Scale up from days to millis
            // Compute the number of days before the current day in this
            // week.  This will be a value 0..6.
            int32_t leadDays = internalGet(field);
            leadDays -= (field == UCAL_DAY_OF_WEEK) ? getFirstDayOfWeek() : 1;
            if (leadDays < 0) leadDays += 7;
            double min2 = internalGetTime() - leadDays * kOneDay;
            double newtime = uprv_fmod((internalGetTime() + delta - min2), kOneWeek);
            if (newtime < 0) newtime += kOneWeek;
            setTimeInMillis(newtime + min2, status);
            return;
        }
    case UCAL_DAY_OF_WEEK_IN_MONTH:
        {
            // Roll the day of week in the month using millis.  Determine
            // the first day of the week in the month, and then the last,
            // and then roll within that range.
            double delta = amount * kOneWeek; // Scale up from weeks to millis
            // Find the number of same days of the week before this one
            // in this month.
            int32_t preWeeks = (internalGet(UCAL_DAY_OF_MONTH) - 1) / 7;
            // Find the number of same days of the week after this one
            // in this month.
            int32_t postWeeks = (getActualMaximum(UCAL_DAY_OF_MONTH,status) -
                internalGet(UCAL_DAY_OF_MONTH)) / 7;
            // From these compute the min and gap millis for rolling.
            double min2 = internalGetTime() - preWeeks * kOneWeek;
            double gap2 = kOneWeek * (preWeeks + postWeeks + 1); // Must add 1!
            // Roll within this range
            double newtime = uprv_fmod((internalGetTime() + delta - min2), gap2);
            if (newtime < 0) newtime += gap2;
            setTimeInMillis(newtime + min2, status);
            return;
        }
    case UCAL_JULIAN_DAY:
        set(field, internalGet(field) + amount);
        return;
    default:
        // Other fields cannot be rolled by this method
#if defined (U_DEBUG_CAL)
        fprintf(stderr, "%s:%d: ILLEGAL ARG because of roll on non-rollable field %s\n",
            __FILE__, __LINE__,fldName(field));
#endif
        status = U_ILLEGAL_ARGUMENT_ERROR;
    }
}

void Calendar::add(EDateFields field, int32_t amount, UErrorCode& status)
{
    Calendar::add((UCalendarDateFields)field, amount, status);
}

// -------------------------------------
void Calendar::add(UCalendarDateFields field, int32_t amount, UErrorCode& status)
{
    if (U_FAILURE(status)) {
       return;
    }
    if (field < 0 || field >= UCAL_FIELD_COUNT) {
        status = U_ILLEGAL_ARGUMENT_ERROR;
        return;
    }
    if (amount == 0) {
        return;   // Do nothing!
    }

    // We handle most fields in the same way.  The algorithm is to add
    // a computed amount of millis to the current millis.  The only
    // wrinkle is with DST (and/or a change to the zone's UTC offset, which
    // we'll include with DST) -- for some fields, like the DAY_OF_MONTH,
    // we don't want the wall time to shift due to changes in DST.  If the
    // result of the add operation is to move from DST to Standard, or
    // vice versa, we need to adjust by an hour forward or back,
    // respectively.  For such fields we set keepWallTimeInvariant to true.

    // We only adjust the DST for fields larger than an hour.  For
    // fields smaller than an hour, we cannot adjust for DST without
    // causing problems.  for instance, if you add one hour to April 5,
    // 1998, 1:00 AM, in PST, the time becomes "2:00 AM PDT" (an
    // illegal value), but then the adjustment sees the change and
    // compensates by subtracting an hour.  As a result the time
    // doesn't advance at all.

    // For some fields larger than a day, such as a UCAL_MONTH, we pin the
    // UCAL_DAY_OF_MONTH.  This allows <March 31>.add(UCAL_MONTH, 1) to be
    // <April 30>, rather than <April 31> => <May 1>.

    double delta = amount; // delta in ms
    UBool keepWallTimeInvariant = true;

    switch (field) {
    case UCAL_ERA:
        set(field, get(field, status) + amount);
        pinField(UCAL_ERA, status);
        return;

    case UCAL_YEAR:
    case UCAL_YEAR_WOY:
      {
        // * If era=0 and years go backwards in time, change sign of amount.
        // * Until we have new API per #9393, we temporarily hardcode knowledge of
        //   which calendars have era 0 years that go backwards.
        // * Note that for UCAL_YEAR (but not UCAL_YEAR_WOY) we could instead handle
        //   this by applying the amount to the UCAL_EXTENDED_YEAR field; but since
        //   we would still need to handle UCAL_YEAR_WOY as below, might as well
        //   also handle UCAL_YEAR the same way.
        int32_t era = get(UCAL_ERA, status);
        if (era == 0) {
          const char * calType = getType();
          if ( uprv_strcmp(calType,"gregorian")==0 || uprv_strcmp(calType,"roc")==0 || uprv_strcmp(calType,"coptic")==0 ) {
            amount = -amount;
          }
        }
      }
      // Fall through into normal handling
      U_FALLTHROUGH;
    case UCAL_EXTENDED_YEAR:
    case UCAL_MONTH:
    case UCAL_ORDINAL_MONTH:
      {
        UBool oldLenient = isLenient();
        setLenient(true);
        set(field, get(field, status) + amount);
        pinField(UCAL_DAY_OF_MONTH, status);
        if(oldLenient==false) {
          complete(status); /* force recalculate */
          setLenient(oldLenient);
        }
      }
      return;

    case UCAL_WEEK_OF_YEAR:
    case UCAL_WEEK_OF_MONTH:
    case UCAL_DAY_OF_WEEK_IN_MONTH:
        delta *= kOneWeek;
        break;

    case UCAL_AM_PM:
        delta *= 12 * kOneHour;
        break;

    case UCAL_DAY_OF_MONTH:
    case UCAL_DAY_OF_YEAR:
    case UCAL_DAY_OF_WEEK:
    case UCAL_DOW_LOCAL:
    case UCAL_JULIAN_DAY:
        delta *= kOneDay;
        break;

    case UCAL_HOUR_OF_DAY:
    case UCAL_HOUR:
        delta *= kOneHour;
        keepWallTimeInvariant = false;
        break;

    case UCAL_MINUTE:
        delta *= kOneMinute;
        keepWallTimeInvariant = false;
        break;

    case UCAL_SECOND:
        delta *= kOneSecond;
        keepWallTimeInvariant = false;
        break;

    case UCAL_MILLISECOND:
    case UCAL_MILLISECONDS_IN_DAY:
        keepWallTimeInvariant = false;
        break;

    default:
#if defined (U_DEBUG_CAL)
        fprintf(stderr, "%s:%d: ILLEGAL ARG because field %s not addable",
            __FILE__, __LINE__, fldName(field));
#endif
        status = U_ILLEGAL_ARGUMENT_ERROR;
        return;
        //  throw new IllegalArgumentException("Calendar.add(" + fieldName(field) +
        //                                     ") not supported");
    }

    // In order to keep the wall time invariant (for fields where this is
    // appropriate), check the combined DST & ZONE offset before and
    // after the add() operation. If it changes, then adjust the millis
    // to compensate.
    int32_t prevOffset = 0;
    int32_t prevWallTime = 0;
    if (keepWallTimeInvariant) {
        prevOffset = get(UCAL_DST_OFFSET, status) + get(UCAL_ZONE_OFFSET, status);
        prevWallTime = get(UCAL_MILLISECONDS_IN_DAY, status);
    }

    setTimeInMillis(getTimeInMillis(status) + delta, status);

    if (keepWallTimeInvariant) {
        int32_t newWallTime = get(UCAL_MILLISECONDS_IN_DAY, status);
        if (newWallTime != prevWallTime) {
            // There is at least one zone transition between the base
            // time and the result time. As the result, wall time has
            // changed.
            UDate t = internalGetTime();
            int32_t newOffset = get(UCAL_DST_OFFSET, status) + get(UCAL_ZONE_OFFSET, status);
            if (newOffset != prevOffset) {
                // When the difference of the previous UTC offset and
                // the new UTC offset exceeds 1 full day, we do not want
                // to roll over/back the date. For now, this only happens
                // in Samoa (Pacific/Apia) on Dec 30, 2011. See ticket:9452.
                int32_t adjAmount = prevOffset - newOffset;
                adjAmount = adjAmount >= 0 ? adjAmount % (int32_t)kOneDay : -(-adjAmount % (int32_t)kOneDay);
                if (adjAmount != 0) {
                    setTimeInMillis(t + adjAmount, status);
                    newWallTime = get(UCAL_MILLISECONDS_IN_DAY, status);
                }
                if (newWallTime != prevWallTime) {
                    // The result wall time or adjusted wall time was shifted because
                    // the target wall time does not exist on the result date.
                    switch (fSkippedWallTime) {
                    case UCAL_WALLTIME_FIRST:
                        if (adjAmount > 0) {
                            setTimeInMillis(t, status);
                        }
                        break;
                    case UCAL_WALLTIME_LAST:
                        if (adjAmount < 0) {
                            setTimeInMillis(t, status);
                        }
                        break;
                    case UCAL_WALLTIME_NEXT_VALID:
                        UDate tmpT = adjAmount > 0 ? internalGetTime() : t;
                        UDate immediatePrevTrans;
                        UBool hasTransition = getImmediatePreviousZoneTransition(tmpT, &immediatePrevTrans, status);
                        if (U_SUCCESS(status) && hasTransition) {
                            setTimeInMillis(immediatePrevTrans, status);
                        }
                        break;
                    }
                }
            }
        }
    }
}

// -------------------------------------
int32_t Calendar::fieldDifference(UDate when, EDateFields field, UErrorCode& status) {
    return fieldDifference(when, (UCalendarDateFields) field, status);
}

int32_t Calendar::fieldDifference(UDate targetMs, UCalendarDateFields field, UErrorCode& ec) {
    if (U_FAILURE(ec)) {
        return 0;
    }
    if (field < 0 || field >= UCAL_FIELD_COUNT) {
        ec = U_ILLEGAL_ARGUMENT_ERROR;
        return 0;
    }
    int32_t min = 0;
    double startMs = getTimeInMillis(ec);
    // Always add from the start millis.  This accommodates
    // operations like adding years from February 29, 2000 up to
    // February 29, 2004.  If 1, 1, 1, 1 is added to the year
    // field, the DOM gets pinned to 28 and stays there, giving an
    // incorrect DOM difference of 1.  We have to add 1, reset, 2,
    // reset, 3, reset, 4.
    if (startMs < targetMs) {
        int32_t max = 1;
        // Find a value that is too large
        while (U_SUCCESS(ec)) {
            setTimeInMillis(startMs, ec);
            add(field, max, ec);
            double ms = getTimeInMillis(ec);
            if (ms == targetMs) {
                return max;
            } else if (ms > targetMs) {
                break;
            } else if (max < INT32_MAX) {
                min = max;
                max <<= 1;
                if (max < 0) {
                    max = INT32_MAX;
                }
            } else {
                // Field difference too large to fit into int32_t
#if defined (U_DEBUG_CAL)
                fprintf(stderr, "%s:%d: ILLEGAL ARG because field %s's max too large for int32_t\n",
                    __FILE__, __LINE__, fldName(field));
#endif
                ec = U_ILLEGAL_ARGUMENT_ERROR;
            }
        }
        // Do a binary search
        while ((max - min) > 1 && U_SUCCESS(ec)) {
            int32_t t = min + (max - min)/2; // make sure intermediate values don't exceed INT32_MAX
            setTimeInMillis(startMs, ec);
            add(field, t, ec);
            double ms = getTimeInMillis(ec);
            if (ms == targetMs) {
                return t;
            } else if (ms > targetMs) {
                max = t;
            } else {
                min = t;
            }
        }
    } else if (startMs > targetMs) {
        int32_t max = -1;
        // Find a value that is too small
        while (U_SUCCESS(ec)) {
            setTimeInMillis(startMs, ec);
            add(field, max, ec);
            double ms = getTimeInMillis(ec);
            if (ms == targetMs) {
                return max;
            } else if (ms < targetMs) {
                break;
            } else {
                min = max;
                max = (int32_t)((uint32_t)(max) << 1);
                if (max == 0) {
                    // Field difference too large to fit into int32_t
#if defined (U_DEBUG_CAL)
                    fprintf(stderr, "%s:%d: ILLEGAL ARG because field %s's max too large for int32_t\n",
                        __FILE__, __LINE__, fldName(field));
#endif
                    ec = U_ILLEGAL_ARGUMENT_ERROR;
                }
            }
        }
        // Do a binary search
        while ((min - max) > 1 && U_SUCCESS(ec)) {
            int32_t t = min + (max - min)/2; // make sure intermediate values don't exceed INT32_MAX
            setTimeInMillis(startMs, ec);
            add(field, t, ec);
            double ms = getTimeInMillis(ec);
            if (ms == targetMs) {
                return t;
            } else if (ms < targetMs) {
                max = t;
            } else {
                min = t;
            }
        }
    }
    // Set calendar to end point
    setTimeInMillis(startMs, ec);
    add(field, min, ec);

    /* Test for buffer overflows */
    if(U_FAILURE(ec)) {
        return 0;
    }
    return min;
}

// -------------------------------------

void
Calendar::adoptTimeZone(TimeZone* zone)
{
    // Do nothing if passed-in zone is nullptr
    if (zone == nullptr) {
        return;
    }

    // fZone should always be non-null
    delete fZone;
    fZone = zone;

    // if the zone changes, we need to recompute the time fields
    fAreFieldsSet = false;
}

// -------------------------------------
void
Calendar::setTimeZone(const TimeZone& zone)
{
    adoptTimeZone(zone.clone());
}

// -------------------------------------

const TimeZone&
Calendar::getTimeZone() const
{
    U_ASSERT(fZone != nullptr);
    return *fZone;
}

// -------------------------------------

TimeZone*
Calendar::orphanTimeZone()
{
    // we let go of the time zone; the new time zone is the system default time zone
    TimeZone *defaultZone = TimeZone::createDefault();
    if (defaultZone == nullptr) {
        // No error handling available. Must keep fZone non-nullptr, there are many unchecked uses.
        return nullptr;
    }
    TimeZone *z = fZone;
    fZone = defaultZone;
    return z;
}

// -------------------------------------

void
Calendar::setLenient(UBool lenient)
{
    fLenient = lenient;
}

// -------------------------------------

UBool
Calendar::isLenient() const
{
    return fLenient;
}

// -------------------------------------

void
Calendar::setRepeatedWallTimeOption(UCalendarWallTimeOption option)
{
    if (option == UCAL_WALLTIME_LAST || option == UCAL_WALLTIME_FIRST) {
        fRepeatedWallTime = option;
    }
}

// -------------------------------------

UCalendarWallTimeOption
Calendar::getRepeatedWallTimeOption() const
{
    return fRepeatedWallTime;
}

// -------------------------------------

void
Calendar::setSkippedWallTimeOption(UCalendarWallTimeOption option)
{
    fSkippedWallTime = option;
}

// -------------------------------------

UCalendarWallTimeOption
Calendar::getSkippedWallTimeOption() const
{
    return fSkippedWallTime;
}

// -------------------------------------

void
Calendar::setFirstDayOfWeek(UCalendarDaysOfWeek value) UPRV_NO_SANITIZE_UNDEFINED {
    if (fFirstDayOfWeek != value &&
        value >= UCAL_SUNDAY && value <= UCAL_SATURDAY) {
            fFirstDayOfWeek = value;
            fAreFieldsSet = false;
        }
}

// -------------------------------------

Calendar::EDaysOfWeek
Calendar::getFirstDayOfWeek() const
{
    return (Calendar::EDaysOfWeek)fFirstDayOfWeek;
}

UCalendarDaysOfWeek
Calendar::getFirstDayOfWeek(UErrorCode & /*status*/) const
{
    return fFirstDayOfWeek;
}
// -------------------------------------

void
Calendar::setMinimalDaysInFirstWeek(uint8_t value)
{
    // Values less than 1 have the same effect as 1; values greater
    // than 7 have the same effect as 7. However, we normalize values
    // so operator== and so forth work.
    if (value < 1) {
        value = 1;
    } else if (value > 7) {
        value = 7;
    }
    if (fMinimalDaysInFirstWeek != value) {
        fMinimalDaysInFirstWeek = value;
        fAreFieldsSet = false;
    }
}

// -------------------------------------

uint8_t
Calendar::getMinimalDaysInFirstWeek() const
{
    return fMinimalDaysInFirstWeek;
}

// -------------------------------------
// weekend functions, just dummy implementations for now (for API freeze)

UCalendarWeekdayType
Calendar::getDayOfWeekType(UCalendarDaysOfWeek dayOfWeek, UErrorCode &status) const
{
    if (U_FAILURE(status)) {
        return UCAL_WEEKDAY;
    }
    if (dayOfWeek < UCAL_SUNDAY || dayOfWeek > UCAL_SATURDAY) {
        status = U_ILLEGAL_ARGUMENT_ERROR;
        return UCAL_WEEKDAY;
    }
    if (fWeekendOnset == fWeekendCease) {
        if (dayOfWeek != fWeekendOnset)
            return UCAL_WEEKDAY;
        return (fWeekendOnsetMillis == 0) ? UCAL_WEEKEND : UCAL_WEEKEND_ONSET;
    }
    if (fWeekendOnset < fWeekendCease) {
        if (dayOfWeek < fWeekendOnset || dayOfWeek > fWeekendCease) {
            return UCAL_WEEKDAY;
        }
    } else {
        if (dayOfWeek > fWeekendCease && dayOfWeek < fWeekendOnset) {
            return UCAL_WEEKDAY;
        }
    }
    if (dayOfWeek == fWeekendOnset) {
        return (fWeekendOnsetMillis == 0) ? UCAL_WEEKEND : UCAL_WEEKEND_ONSET;
    }
    if (dayOfWeek == fWeekendCease) {
        return (fWeekendCeaseMillis >= 86400000) ? UCAL_WEEKEND : UCAL_WEEKEND_CEASE;
    }
    return UCAL_WEEKEND;
}

int32_t
Calendar::getWeekendTransition(UCalendarDaysOfWeek dayOfWeek, UErrorCode &status) const
{
    if (U_FAILURE(status)) {
        return 0;
    }
    if (dayOfWeek == fWeekendOnset) {
        return fWeekendOnsetMillis;
    } else if (dayOfWeek == fWeekendCease) {
        return fWeekendCeaseMillis;
    }
    status = U_ILLEGAL_ARGUMENT_ERROR;
    return 0;
}

UBool
Calendar::isWeekend(UDate date, UErrorCode &status) const
{
    if (U_FAILURE(status)) {
        return false;
    }
    // clone the calendar so we don't mess with the real one.
    Calendar *work = this->clone();
    if (work == nullptr) {
        status = U_MEMORY_ALLOCATION_ERROR;
        return false;
    }
    UBool result = false;
    work->setTime(date, status);
    if (U_SUCCESS(status)) {
        result = work->isWeekend();
    }
    delete work;
    return result;
}

UBool
Calendar::isWeekend() const
{
    UErrorCode status = U_ZERO_ERROR;
    UCalendarDaysOfWeek dayOfWeek = (UCalendarDaysOfWeek)get(UCAL_DAY_OF_WEEK, status);
    UCalendarWeekdayType dayType = getDayOfWeekType(dayOfWeek, status);
    if (U_SUCCESS(status)) {
        switch (dayType) {
            case UCAL_WEEKDAY:
                return false;
            case UCAL_WEEKEND:
                return true;
            case UCAL_WEEKEND_ONSET:
            case UCAL_WEEKEND_CEASE:
                // Use internalGet() because the above call to get() populated all fields.
                {
                    int32_t millisInDay = internalGet(UCAL_MILLISECONDS_IN_DAY);
                    int32_t transitionMillis = getWeekendTransition(dayOfWeek, status);
                    if (U_SUCCESS(status)) {
                        return (dayType == UCAL_WEEKEND_ONSET)?
                            (millisInDay >= transitionMillis):
                            (millisInDay <  transitionMillis);
                    }
                    // else fall through, return false
                    U_FALLTHROUGH;
                }
            default:
                break;
        }
    }
    return false;
}

// ------------------------------------- limits

int32_t
Calendar::getMinimum(EDateFields field) const {
    return getLimit((UCalendarDateFields) field,UCAL_LIMIT_MINIMUM);
}

int32_t
Calendar::getMinimum(UCalendarDateFields field) const
{
    return getLimit(field,UCAL_LIMIT_MINIMUM);
}

// -------------------------------------
int32_t
Calendar::getMaximum(EDateFields field) const
{
    return getLimit((UCalendarDateFields) field,UCAL_LIMIT_MAXIMUM);
}

int32_t
Calendar::getMaximum(UCalendarDateFields field) const
{
    return getLimit(field,UCAL_LIMIT_MAXIMUM);
}

// -------------------------------------
int32_t
Calendar::getGreatestMinimum(EDateFields field) const
{
    return getLimit((UCalendarDateFields)field,UCAL_LIMIT_GREATEST_MINIMUM);
}

int32_t
Calendar::getGreatestMinimum(UCalendarDateFields field) const
{
    return getLimit(field,UCAL_LIMIT_GREATEST_MINIMUM);
}

// -------------------------------------
int32_t
Calendar::getLeastMaximum(EDateFields field) const
{
    return getLimit((UCalendarDateFields) field,UCAL_LIMIT_LEAST_MAXIMUM);
}

int32_t
Calendar::getLeastMaximum(UCalendarDateFields field) const
{
    return getLimit( field,UCAL_LIMIT_LEAST_MAXIMUM);
}

// -------------------------------------
int32_t
Calendar::getActualMinimum(EDateFields field, UErrorCode& status) const
{
    return getActualMinimum((UCalendarDateFields) field, status);
}

int32_t Calendar::getLimit(UCalendarDateFields field, ELimitType limitType) const {
    switch (field) {
    case UCAL_DAY_OF_WEEK:
    case UCAL_AM_PM:
    case UCAL_HOUR:
    case UCAL_HOUR_OF_DAY:
    case UCAL_MINUTE:
    case UCAL_SECOND:
    case UCAL_MILLISECOND:
    case UCAL_ZONE_OFFSET:
    case UCAL_DST_OFFSET:
    case UCAL_DOW_LOCAL:
    case UCAL_JULIAN_DAY:
    case UCAL_MILLISECONDS_IN_DAY:
    case UCAL_IS_LEAP_MONTH:
        return kCalendarLimits[field][limitType];

    case UCAL_WEEK_OF_MONTH:
        {
            int32_t limit;
            if (limitType == UCAL_LIMIT_MINIMUM) {
                limit = getMinimalDaysInFirstWeek() == 1 ? 1 : 0;
            } else if (limitType == UCAL_LIMIT_GREATEST_MINIMUM) {
                limit = 1;
            } else {
                int32_t minDaysInFirst = getMinimalDaysInFirstWeek();
                int32_t daysInMonth = handleGetLimit(UCAL_DAY_OF_MONTH, limitType);
                if (limitType == UCAL_LIMIT_LEAST_MAXIMUM) {
                    limit = (daysInMonth + (7 - minDaysInFirst)) / 7;
                } else { // limitType == UCAL_LIMIT_MAXIMUM
                    limit = (daysInMonth + 6 + (7 - minDaysInFirst)) / 7;
                }
            }
            return limit;
        }
    default:
        return handleGetLimit(field, limitType);
    }
}

int32_t
Calendar::getActualMinimum(UCalendarDateFields field, UErrorCode& status) const
{
    if (U_FAILURE(status)) {
       return 0;
    }
    if (field < 0 || field >= UCAL_FIELD_COUNT) {
        status = U_ILLEGAL_ARGUMENT_ERROR;
        return 0;
    }
    int32_t fieldValue = getGreatestMinimum(field);
    int32_t endValue = getMinimum(field);

    // if we know that the minimum value is always the same, just return it
    if (fieldValue == endValue) {
        return fieldValue;
    }

    // clone the calendar so we don't mess with the real one, and set it to
    // accept anything for the field values
    Calendar *work = this->clone();
    if (work == nullptr) {
        status = U_MEMORY_ALLOCATION_ERROR;
        return 0;
    }
    work->setLenient(true);

    // now try each value from getLeastMaximum() to getMaximum() one by one until
    // we get a value that normalizes to another value.  The last value that
    // normalizes to itself is the actual minimum for the current date
    int32_t result = fieldValue;

    do {
        work->set(field, fieldValue);
        if (work->get(field, status) != fieldValue) {
            break;
        }
        else {
            result = fieldValue;
            fieldValue--;
        }
    } while (fieldValue >= endValue);

    delete work;

    /* Test for buffer overflows */
    if(U_FAILURE(status)) {
        return 0;
    }
    return result;
}

// -------------------------------------

UBool
Calendar::inDaylightTime(UErrorCode& status) const
{
    if (U_FAILURE(status) || !getTimeZone().useDaylightTime()) {
        return false;
    }

    // Force an update of the state of the Calendar.
    ((Calendar*)this)->complete(status); // cast away const

    return (UBool)(U_SUCCESS(status) ? (internalGet(UCAL_DST_OFFSET) != 0) : false);
}

bool
Calendar::inTemporalLeapYear(UErrorCode& status) const
{
    // Default to Gregorian based leap year rule.
    return getActualMaximum(UCAL_DAY_OF_YEAR, status) == 366;
}

// -------------------------------------

static const char * const gTemporalMonthCodes[] = {
    "M01", "M02", "M03", "M04", "M05", "M06",
    "M07", "M08", "M09", "M10", "M11", "M12", nullptr
};

const char*
Calendar::getTemporalMonthCode(UErrorCode& status) const
{
    int32_t month = get(UCAL_MONTH, status);
    if (U_FAILURE(status)) {
        return nullptr;
    }
    U_ASSERT(month < 12);
    U_ASSERT(internalGet(UCAL_IS_LEAP_MONTH) == 0);
    return gTemporalMonthCodes[month];
}

void
Calendar::setTemporalMonthCode(const char* code, UErrorCode& status )
{
    if (U_FAILURE(status)) {
        return;
    }
    int32_t len = static_cast<int32_t>(uprv_strlen(code));
    if (len == 3 && code[0] == 'M') {
        for (int m = 0; gTemporalMonthCodes[m] != nullptr; m++) {
            if (uprv_strcmp(code, gTemporalMonthCodes[m]) == 0) {
                set(UCAL_MONTH, m);
                set(UCAL_IS_LEAP_MONTH, 0);
                return;
            }
        }
    }
    status = U_ILLEGAL_ARGUMENT_ERROR;
}

// -------------------------------------

/**
* Ensure that each field is within its valid range by calling {@link
* #validateField(int)} on each field that has been set.  This method
* should only be called if this calendar is not lenient.
* @see #isLenient
* @see #validateField(int)
*/
void Calendar::validateFields(UErrorCode &status) {
    if (U_FAILURE(status)) {
       return;
    }
    for (int32_t field = 0; U_SUCCESS(status) && (field < UCAL_FIELD_COUNT); field++) {
        if (fStamp[field] >= kMinimumUserStamp) {
            validateField((UCalendarDateFields)field, status);
        }
    }
}

/**
* Validate a single field of this calendar.  Subclasses should
* override this method to validate any calendar-specific fields.
* Generic fields can be handled by
* <code>Calendar.validateField()</code>.
* @see #validateField(int, int, int)
*/
void Calendar::validateField(UCalendarDateFields field, UErrorCode &status) {
    if (U_FAILURE(status)) {
       return;
    }
    if (field < 0 || field >= UCAL_FIELD_COUNT) {
        status = U_ILLEGAL_ARGUMENT_ERROR;
        return;
    }
    int32_t y;
    switch (field) {
    case UCAL_DAY_OF_MONTH:
        y = handleGetExtendedYear();
        validateField(field, 1, handleGetMonthLength(y, internalGetMonth()), status);
        break;
    case UCAL_DAY_OF_YEAR:
        y = handleGetExtendedYear();
        validateField(field, 1, handleGetYearLength(y), status);
        break;
    case UCAL_DAY_OF_WEEK_IN_MONTH:
        if (internalGet(field) == 0) {
#if defined (U_DEBUG_CAL)
            fprintf(stderr, "%s:%d: ILLEGAL ARG because DOW in month cannot be 0\n",
                __FILE__, __LINE__);
#endif
            status = U_ILLEGAL_ARGUMENT_ERROR; // "DAY_OF_WEEK_IN_MONTH cannot be zero"
            return;
        }
        validateField(field, getMinimum(field), getMaximum(field), status);
        break;
    default:
        validateField(field, getMinimum(field), getMaximum(field), status);
        break;
    }
}

/**
* Validate a single field of this calendar given its minimum and
* maximum allowed value.  If the field is out of range, throw a
* descriptive <code>IllegalArgumentException</code>.  Subclasses may
* use this method in their implementation of {@link
* #validateField(int)}.
*/
void Calendar::validateField(UCalendarDateFields field, int32_t min, int32_t max, UErrorCode& status)
{
    if (U_FAILURE(status)) {
       return;
    }
    if (field < 0 || field >= UCAL_FIELD_COUNT) {
        status = U_ILLEGAL_ARGUMENT_ERROR;
        return;
    }
    int32_t value = fFields[field];
    if (value < min || value > max) {
#if defined (U_DEBUG_CAL)
        fprintf(stderr, "%s:%d: ILLEGAL ARG because of field %s out of range %d..%d  at %d\n",
            __FILE__, __LINE__,fldName(field),min,max,value);
#endif
        status = U_ILLEGAL_ARGUMENT_ERROR;
        return;
    }
}

// -------------------------

const UFieldResolutionTable* Calendar::getFieldResolutionTable() const {
    return kDatePrecedence;
}


UCalendarDateFields Calendar::newerField(UCalendarDateFields defaultField, UCalendarDateFields alternateField) const
{
    if (fStamp[alternateField] > fStamp[defaultField]) {
        return alternateField;
    }
    return defaultField;
}

UCalendarDateFields Calendar::resolveFields(const UFieldResolutionTable* precedenceTable) const {
    int32_t bestField = UCAL_FIELD_COUNT;
    int32_t tempBestField;
    for (int32_t g=0; precedenceTable[g][0][0] != -1 && (bestField == UCAL_FIELD_COUNT); ++g) {
        int32_t bestStamp = kUnset;
        for (int32_t l=0; precedenceTable[g][l][0] != -1; ++l) {
            int32_t lineStamp = kUnset;
            // Skip over first entry if it is negative
            for (int32_t i=((precedenceTable[g][l][0]>=kResolveRemap)?1:0); precedenceTable[g][l][i]!=-1; ++i) {
                U_ASSERT(precedenceTable[g][l][i] < UCAL_FIELD_COUNT);
                int32_t s = fStamp[precedenceTable[g][l][i]];
                // If any field is unset then don't use this line
                if (s == kUnset) {
                    goto linesInGroup;
                } else if(s > lineStamp) {
                    lineStamp = s;
                }
            }
            // Record new maximum stamp & field no.
            if (lineStamp > bestStamp) {
                tempBestField = precedenceTable[g][l][0]; // First field refers to entire line
                if (tempBestField >= kResolveRemap) {
                    tempBestField &= (kResolveRemap-1);
                    // This check is needed to resolve some issues with UCAL_YEAR precedence mapping
                    if (tempBestField != UCAL_DATE || (fStamp[UCAL_WEEK_OF_MONTH] < fStamp[tempBestField])) {
                        bestField = tempBestField;
                    }
                } else {
                    bestField = tempBestField;
                }

                if (bestField == tempBestField) {
                    bestStamp = lineStamp;
                }
            }
linesInGroup:
            ;
        }
    }
    return (UCalendarDateFields)bestField;
}

const UFieldResolutionTable Calendar::kDatePrecedence[] =
{
    {
        { UCAL_DAY_OF_MONTH, kResolveSTOP },
        { UCAL_WEEK_OF_YEAR, UCAL_DAY_OF_WEEK, kResolveSTOP },
        { UCAL_WEEK_OF_MONTH, UCAL_DAY_OF_WEEK, kResolveSTOP },
        { UCAL_DAY_OF_WEEK_IN_MONTH, UCAL_DAY_OF_WEEK, kResolveSTOP },
        { UCAL_WEEK_OF_YEAR, UCAL_DOW_LOCAL, kResolveSTOP },
        { UCAL_WEEK_OF_MONTH, UCAL_DOW_LOCAL, kResolveSTOP },
        { UCAL_DAY_OF_WEEK_IN_MONTH, UCAL_DOW_LOCAL, kResolveSTOP },
        { UCAL_DAY_OF_YEAR, kResolveSTOP },
        { kResolveRemap | UCAL_DAY_OF_MONTH, UCAL_YEAR, kResolveSTOP },  // if YEAR is set over YEAR_WOY use DAY_OF_MONTH
        { kResolveRemap | UCAL_WEEK_OF_YEAR, UCAL_YEAR_WOY, kResolveSTOP },  // if YEAR_WOY is set,  calc based on WEEK_OF_YEAR
        { kResolveSTOP }
    },
    {
        { UCAL_WEEK_OF_YEAR, kResolveSTOP },
        { UCAL_WEEK_OF_MONTH, kResolveSTOP },
        { UCAL_DAY_OF_WEEK_IN_MONTH, kResolveSTOP },
        { kResolveRemap | UCAL_DAY_OF_WEEK_IN_MONTH, UCAL_DAY_OF_WEEK, kResolveSTOP },
        { kResolveRemap | UCAL_DAY_OF_WEEK_IN_MONTH, UCAL_DOW_LOCAL, kResolveSTOP },
        { kResolveSTOP }
    },
    {{kResolveSTOP}}
};


const UFieldResolutionTable Calendar::kMonthPrecedence[] =
{
    {
        { UCAL_MONTH