// © 2016 and later: Unicode, Inc. and others.

// License & terms of use: http://www.unicode.org/copyright.html

/*

 *******************************************************************************

 * Copyright (C) 1997-2013, International Business Machines Corporation and

 * others. All Rights Reserved.

 *******************************************************************************

 *

 * File SIMPLETZ.H

 *

 * Modification History:

 *

 *   Date        Name        Description

 *   12/05/96    clhuang     Creation.

 *   04/21/97    aliu        Fixed miscellaneous bugs found by inspection and

 *                           testing.

 *   07/29/97    aliu        Ported source bodies back from Java version with

 *                           numerous feature enhancements and bug fixes.

 *   08/10/98    stephen     JDK 1.2 sync.

 *   09/17/98    stephen     Fixed getOffset() for last hour of year and DST

 *   12/02/99    aliu        Added TimeMode and constructor and setStart/EndRule

 *                           methods that take TimeMode. Whitespace cleanup.

 ********************************************************************************

 */

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

#include "unicode/utypes.h"

#if !UCONFIG_NO_FORMATTING

#include "unicode/simpletz.h"

#include "unicode/gregocal.h"

#include "unicode/smpdtfmt.h"

#include "cmemory.h"

#include "gregoimp.h"

#include "umutex.h"

U_NAMESPACE_BEGIN

UOBJECT_DEFINE_RTTI_IMPLEMENTATION(SimpleTimeZone)

// Use only for decodeStartRule() and decodeEndRule() where the year is not

// available. Set February to 29 days to accommodate rules with that date

// and day-of-week-on-or-before-that-date mode (DOW_LE_DOM_MODE).

// The compareToRule() method adjusts to February 28 in non-leap years.

//

// For actual getOffset() calculations, use Grego::monthLength() and

// Grego::previousMonthLength() which take leap years into account.

// We handle leap years assuming always

// Gregorian, since we know they didn't have daylight time when

// Gregorian calendar started.

const int8_t SimpleTimeZone::STATICMONTHLENGTH[] = {31,29,31,30,31,30,31,31,30,31,30,31};

static const UChar DST_STR[] = {0x0028,0x0044,0x0053,0x0054,0x0029,0}; // "(DST)"

static const UChar STD_STR[] = {0x0028,0x0053,0x0054,0x0044,0x0029,0}; // "(STD)"

// *****************************************************************************

// class SimpleTimeZone

// *****************************************************************************

SimpleTimeZone::SimpleTimeZone(int32_t rawOffsetGMT, const UnicodeString& ID)

:   BasicTimeZone(ID),

    startMonth(0),

    startDay(0),

    startDayOfWeek(0),

    startTime(0),

    startTimeMode(WALL_TIME),

    endTimeMode(WALL_TIME),

    endMonth(0),

    endDay(0),

    endDayOfWeek(0),

    endTime(0),

    startYear(0),

    rawOffset(rawOffsetGMT),

    useDaylight(FALSE),

    startMode(DOM_MODE),

    endMode(DOM_MODE),

    dstSavings(U_MILLIS_PER_HOUR)

{

    clearTransitionRules();

}

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

SimpleTimeZone::SimpleTimeZone(int32_t rawOffsetGMT, const UnicodeString& ID,

    int8_t savingsStartMonth, int8_t savingsStartDay,

    int8_t savingsStartDayOfWeek, int32_t savingsStartTime,

    int8_t savingsEndMonth, int8_t savingsEndDay,

    int8_t savingsEndDayOfWeek, int32_t savingsEndTime,

    UErrorCode& status)

:   BasicTimeZone(ID)

{

    clearTransitionRules();

    construct(rawOffsetGMT,

              savingsStartMonth, savingsStartDay, savingsStartDayOfWeek,

              savingsStartTime, WALL_TIME,

              savingsEndMonth, savingsEndDay, savingsEndDayOfWeek,

              savingsEndTime, WALL_TIME,

              U_MILLIS_PER_HOUR, status);

}

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

SimpleTimeZone::SimpleTimeZone(int32_t rawOffsetGMT, const UnicodeString& ID,

    int8_t savingsStartMonth, int8_t savingsStartDay,

    int8_t savingsStartDayOfWeek, int32_t savingsStartTime,

    int8_t savingsEndMonth, int8_t savingsEndDay,

    int8_t savingsEndDayOfWeek, int32_t savingsEndTime,

    int32_t savingsDST, UErrorCode& status)

:   BasicTimeZone(ID)

{

    clearTransitionRules();

    construct(rawOffsetGMT,

              savingsStartMonth, savingsStartDay, savingsStartDayOfWeek,

              savingsStartTime, WALL_TIME,

              savingsEndMonth, savingsEndDay, savingsEndDayOfWeek,

              savingsEndTime, WALL_TIME,

              savingsDST, status);

}

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

SimpleTimeZone::SimpleTimeZone(int32_t rawOffsetGMT, const UnicodeString& ID,

    int8_t savingsStartMonth, int8_t savingsStartDay,

    int8_t savingsStartDayOfWeek, int32_t savingsStartTime,

    TimeMode savingsStartTimeMode,

    int8_t savingsEndMonth, int8_t savingsEndDay,

    int8_t savingsEndDayOfWeek, int32_t savingsEndTime,

    TimeMode savingsEndTimeMode,

    int32_t savingsDST, UErrorCode& status)

:   BasicTimeZone(ID)

{

    clearTransitionRules();

    construct(rawOffsetGMT,

              savingsStartMonth, savingsStartDay, savingsStartDayOfWeek,

              savingsStartTime, savingsStartTimeMode,

              savingsEndMonth, savingsEndDay, savingsEndDayOfWeek,

              savingsEndTime, savingsEndTimeMode,

              savingsDST, status);

}

/**

 * Internal construction method.

 */

void SimpleTimeZone::construct(int32_t rawOffsetGMT,

                               int8_t savingsStartMonth,

                               int8_t savingsStartDay,

                               int8_t savingsStartDayOfWeek,

                               int32_t savingsStartTime,

                               TimeMode savingsStartTimeMode,

                               int8_t savingsEndMonth,

                               int8_t savingsEndDay,

                               int8_t savingsEndDayOfWeek,

                               int32_t savingsEndTime,

                               TimeMode savingsEndTimeMode,

                               int32_t savingsDST,

                               UErrorCode& status)

{

    this->rawOffset      = rawOffsetGMT;

    this->startMonth     = savingsStartMonth;

    this->startDay       = savingsStartDay;

    this->startDayOfWeek = savingsStartDayOfWeek;

    this->startTime      = savingsStartTime;

    this->startTimeMode  = savingsStartTimeMode;

    this->endMonth       = savingsEndMonth;

    this->endDay         = savingsEndDay;

    this->endDayOfWeek   = savingsEndDayOfWeek;

    this->endTime        = savingsEndTime;

    this->endTimeMode    = savingsEndTimeMode;

    this->dstSavings     = savingsDST;

    this->startYear      = 0;

    this->startMode      = DOM_MODE;

    this->endMode        = DOM_MODE;

    decodeRules(status);

    if (savingsDST == 0) {

        status = U_ILLEGAL_ARGUMENT_ERROR;

    }

}

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

SimpleTimeZone::~SimpleTimeZone()

{

    deleteTransitionRules();

}

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

// Called by TimeZone::createDefault(), then clone() inside a Mutex - be careful.

SimpleTimeZone::SimpleTimeZone(const SimpleTimeZone &source)

:   BasicTimeZone(source)

{

    *this = source;

}

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

// Called by TimeZone::createDefault(), then clone() inside a Mutex - be careful.

SimpleTimeZone &

SimpleTimeZone::operator=(const SimpleTimeZone &right)

{

    if (this != &right)

    {

        TimeZone::operator=(right);

        rawOffset      = right.rawOffset;

        startMonth     = right.startMonth;

        startDay       = right.startDay;

        startDayOfWeek = right.startDayOfWeek;

        startTime      = right.startTime;

        startTimeMode  = right.startTimeMode;

        startMode      = right.startMode;

        endMonth       = right.endMonth;

        endDay         = right.endDay;

        endDayOfWeek   = right.endDayOfWeek;

        endTime        = right.endTime;

        endTimeMode    = right.endTimeMode;

        endMode        = right.endMode;

        startYear      = right.startYear;

        dstSavings     = right.dstSavings;

        useDaylight    = right.useDaylight;

        clearTransitionRules();

    }

    return *this;

}

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

bool

SimpleTimeZone::operator==(const TimeZone& that) const

{

    return ((this == &that) ||

            (typeid(*this) == typeid(that) &&

            TimeZone::operator==(that) &&

            hasSameRules(that)));

}

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

// Called by TimeZone::createDefault() inside a Mutex - be careful.

SimpleTimeZone*

SimpleTimeZone::clone() const

{

    return new SimpleTimeZone(*this);

}

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

/**

 * Sets the daylight savings starting year, that is, the year this time zone began

 * observing its specified daylight savings time rules.  The time zone is considered

 * not to observe daylight savings time prior to that year; SimpleTimeZone doesn't

 * support historical daylight-savings-time rules.

 * @param year the daylight savings starting year.

 */

void

SimpleTimeZone::setStartYear(int32_t year)

{

    startYear = year;

    transitionRulesInitialized = FALSE;

}

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

/**

 * Sets the daylight savings starting rule. For example, in the U.S., Daylight Savings

 * Time starts at the first Sunday in April, at 2 AM in standard time.

 * Therefore, you can set the start rule by calling:

 * setStartRule(TimeFields.APRIL, 1, TimeFields.SUNDAY, 2*60*60*1000);

 * The dayOfWeekInMonth and dayOfWeek parameters together specify how to calculate

 * the exact starting date.  Their exact meaning depend on their respective signs,

 * allowing various types of rules to be constructed, as follows:<ul>

 *   <li>If both dayOfWeekInMonth and dayOfWeek are positive, they specify the

 *       day of week in the month (e.g., (2, WEDNESDAY) is the second Wednesday

 *       of the month).

 *   <li>If dayOfWeek is positive and dayOfWeekInMonth is negative, they specify

 *       the day of week in the month counting backward from the end of the month.

 *       (e.g., (-1, MONDAY) is the last Monday in the month)

 *   <li>If dayOfWeek is zero and dayOfWeekInMonth is positive, dayOfWeekInMonth

 *       specifies the day of the month, regardless of what day of the week it is.

 *       (e.g., (10, 0) is the tenth day of the month)

 *   <li>If dayOfWeek is zero and dayOfWeekInMonth is negative, dayOfWeekInMonth

 *       specifies the day of the month counting backward from the end of the

 *       month, regardless of what day of the week it is (e.g., (-2, 0) is the

 *       next-to-last day of the month).

 *   <li>If dayOfWeek is negative and dayOfWeekInMonth is positive, they specify the

 *       first specified day of the week on or after the specified day of the month.

 *       (e.g., (15, -SUNDAY) is the first Sunday after the 15th of the month

 *       [or the 15th itself if the 15th is a Sunday].)

 *   <li>If dayOfWeek and DayOfWeekInMonth are both negative, they specify the

 *       last specified day of the week on or before the specified day of the month.

 *       (e.g., (-20, -TUESDAY) is the last Tuesday before the 20th of the month

 *       [or the 20th itself if the 20th is a Tuesday].)</ul>

 * @param month the daylight savings starting month. Month is 0-based.

 * eg, 0 for January.

 * @param dayOfWeekInMonth the daylight savings starting

 * day-of-week-in-month. Please see the member description for an example.

 * @param dayOfWeek the daylight savings starting day-of-week. Please see

 * the member description for an example.

 * @param time the daylight savings starting time. Please see the member

 * description for an example.

 */

void

SimpleTimeZone::setStartRule(int32_t month, int32_t dayOfWeekInMonth, int32_t dayOfWeek,

                             int32_t time, TimeMode mode, UErrorCode& status)

{

    startMonth     = (int8_t)month;

    startDay       = (int8_t)dayOfWeekInMonth;

    startDayOfWeek = (int8_t)dayOfWeek;

    startTime      = time;

    startTimeMode  = mode;

    decodeStartRule(status);

    transitionRulesInitialized = FALSE;

}

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

void 

SimpleTimeZone::setStartRule(int32_t month, int32_t dayOfMonth, 

                             int32_t time, TimeMode mode, UErrorCode& status) 

{

    setStartRule(month, dayOfMonth, 0, time, mode, status);

}

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

void 

SimpleTimeZone::setStartRule(int32_t month, int32_t dayOfMonth, int32_t dayOfWeek, 

                             int32_t time, TimeMode mode, UBool after, UErrorCode& status)

{

    setStartRule(month, after ? dayOfMonth : -dayOfMonth,

                 -dayOfWeek, time, mode, status);

}

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

/**

 * Sets the daylight savings ending rule. For example, in the U.S., Daylight

 * Savings Time ends at the last (-1) Sunday in October, at 2 AM in standard time.

 * Therefore, you can set the end rule by calling:

 * setEndRule(TimeFields.OCTOBER, -1, TimeFields.SUNDAY, 2*60*60*1000);

 * Various other types of rules can be specified by manipulating the dayOfWeek

 * and dayOfWeekInMonth parameters.  For complete details, see the documentation

 * for setStartRule().

 * @param month the daylight savings ending month. Month is 0-based.

 * eg, 0 for January.

 * @param dayOfWeekInMonth the daylight savings ending

 * day-of-week-in-month. See setStartRule() for a complete explanation.

 * @param dayOfWeek the daylight savings ending day-of-week. See setStartRule()

 * for a complete explanation.

 * @param time the daylight savings ending time. Please see the member

 * description for an example.

 */

void

SimpleTimeZone::setEndRule(int32_t month, int32_t dayOfWeekInMonth, int32_t dayOfWeek,

                           int32_t time, TimeMode mode, UErrorCode& status)

{

    endMonth     = (int8_t)month;

    endDay       = (int8_t)dayOfWeekInMonth;

    endDayOfWeek = (int8_t)dayOfWeek;

    endTime      = time;

    endTimeMode  = mode;

    decodeEndRule(status);

    transitionRulesInitialized = FALSE;

}

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

void 

SimpleTimeZone::setEndRule(int32_t month, int32_t dayOfMonth, 

                           int32_t time, TimeMode mode, UErrorCode& status)

{

    setEndRule(month, dayOfMonth, 0, time, mode, status);

}

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

void 

SimpleTimeZone::setEndRule(int32_t month, int32_t dayOfMonth, int32_t dayOfWeek, 

                           int32_t time, TimeMode mode, UBool after, UErrorCode& status)

{

    setEndRule(month, after ? dayOfMonth : -dayOfMonth,

               -dayOfWeek, time, mode, status);

}

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

int32_t

SimpleTimeZone::getOffset(uint8_t era, int32_t year, int32_t month, int32_t day,

                          uint8_t dayOfWeek, int32_t millis, UErrorCode& status) const

{

    // Check the month before calling Grego::monthLength(). This

    // duplicates the test that occurs in the 7-argument getOffset(),

    // however, this is unavoidable. We don't mind because this method, in

    // fact, should not be called; internal code should always call the

    // 7-argument getOffset(), and outside code should use Calendar.get(int

    // field) with fields ZONE_OFFSET and DST_OFFSET. We can't get rid of

    // this method because it's public API. - liu 8/10/98

    if(month < UCAL_JANUARY || month > UCAL_DECEMBER) {

        status = U_ILLEGAL_ARGUMENT_ERROR;

        return 0;

    }

    return getOffset(era, year, month, day, dayOfWeek, millis, Grego::monthLength(year, month), status);

}

int32_t 

SimpleTimeZone::getOffset(uint8_t era, int32_t year, int32_t month, int32_t day,

                          uint8_t dayOfWeek, int32_t millis, 

                          int32_t /*monthLength*/, UErrorCode& status) const

{

    // Check the month before calling Grego::monthLength(). This

    // duplicates a test that occurs in the 9-argument getOffset(),

    // however, this is unavoidable. We don't mind because this method, in

    // fact, should not be called; internal code should always call the

    // 9-argument getOffset(), and outside code should use Calendar.get(int

    // field) with fields ZONE_OFFSET and DST_OFFSET. We can't get rid of

    // this method because it's public API. - liu 8/10/98

    if (month < UCAL_JANUARY

        || month > UCAL_DECEMBER) {

        status = U_ILLEGAL_ARGUMENT_ERROR;

        return -1;

    }

    // We ignore monthLength because it can be derived from year and month.

    // This is so that February in leap years is calculated correctly.

    // We keep this argument in this function for backwards compatibility.

    return getOffset(era, year, month, day, dayOfWeek, millis,

                     Grego::monthLength(year, month),

                     Grego::previousMonthLength(year, month),

                     status);

}

int32_t 

SimpleTimeZone::getOffset(uint8_t era, int32_t year, int32_t month, int32_t day,

                          uint8_t dayOfWeek, int32_t millis, 

                          int32_t monthLength, int32_t prevMonthLength,

                          UErrorCode& status) const

{

    if(U_FAILURE(status)) return 0;

    if ((era != GregorianCalendar::AD && era != GregorianCalendar::BC)

        || month < UCAL_JANUARY

        || month > UCAL_DECEMBER

        || day < 1

        || day > monthLength

        || dayOfWeek < UCAL_SUNDAY

        || dayOfWeek > UCAL_SATURDAY

        || millis < 0

        || millis >= U_MILLIS_PER_DAY

        || monthLength < 28

        || monthLength > 31

        || prevMonthLength < 28

        || prevMonthLength > 31) {

        status = U_ILLEGAL_ARGUMENT_ERROR;

        return -1;

    }

    int32_t result = rawOffset;

    // Bail out if we are before the onset of daylight savings time

    if(!useDaylight || year < startYear || era != GregorianCalendar::AD) 

        return result;

    // Check for southern hemisphere.  We assume that the start and end

    // month are different.

    UBool southern = (startMonth > endMonth);

    // Compare the date to the starting and ending rules.+1 = date>rule, -1

    // = date<rule, 0 = date==rule.

    int32_t startCompare = compareToRule((int8_t)month, (int8_t)monthLength, (int8_t)prevMonthLength,

                                         (int8_t)day, (int8_t)dayOfWeek, millis,

                                         startTimeMode == UTC_TIME ? -rawOffset : 0,

                                         startMode, (int8_t)startMonth, (int8_t)startDayOfWeek,

                                         (int8_t)startDay, startTime);

    int32_t endCompare = 0;

    /* We don't always have to compute endCompare.  For many instances,

     * startCompare is enough to determine if we are in DST or not.  In the

     * northern hemisphere, if we are before the start rule, we can't have

     * DST.  In the southern hemisphere, if we are after the start rule, we

     * must have DST.  This is reflected in the way the next if statement

     * (not the one immediately following) short circuits. */

    if(southern != (startCompare >= 0)) {

        endCompare = compareToRule((int8_t)month, (int8_t)monthLength, (int8_t)prevMonthLength,

                                   (int8_t)day, (int8_t)dayOfWeek, millis,

                                   endTimeMode == WALL_TIME ? dstSavings :

                                    (endTimeMode == UTC_TIME ? -rawOffset : 0),

                                   endMode, (int8_t)endMonth, (int8_t)endDayOfWeek,

                                   (int8_t)endDay, endTime);

    }

    // Check for both the northern and southern hemisphere cases.  We

    // assume that in the northern hemisphere, the start rule is before the

    // end rule within the calendar year, and vice versa for the southern

    // hemisphere.

    if ((!southern && (startCompare >= 0 && endCompare < 0)) ||

        (southern && (startCompare >= 0 || endCompare < 0)))

        result += dstSavings;

    return result;

}

void

SimpleTimeZone::getOffsetFromLocal(UDate date, UTimeZoneLocalOption nonExistingTimeOpt,

                                   UTimeZoneLocalOption duplicatedTimeOpt, int32_t& rawOffsetGMT,

                                   int32_t& savingsDST, UErrorCode& status) const

{

    if (U_FAILURE(status)) {

        return;

    }

    rawOffsetGMT = getRawOffset();

    int32_t year, month, dom, dow;

    double day = uprv_floor(date / U_MILLIS_PER_DAY);

    int32_t millis = (int32_t) (date - day * U_MILLIS_PER_DAY);

    Grego::dayToFields(day, year, month, dom, dow);

    savingsDST = getOffset(GregorianCalendar::AD, year, month, dom,

                          (uint8_t) dow, millis,

                          Grego::monthLength(year, month),

                          status) - rawOffsetGMT;

    if (U_FAILURE(status)) {

        return;

    }

    UBool recalc = FALSE;

    // Now we need some adjustment

    if (savingsDST > 0) {

        if ((nonExistingTimeOpt & kStdDstMask) == kStandard

            || ((nonExistingTimeOpt & kStdDstMask) != kDaylight && (nonExistingTimeOpt & kFormerLatterMask) != kLatter)) {

            date -= getDSTSavings();

            recalc = TRUE;

        }

    } else {

        if ((duplicatedTimeOpt & kStdDstMask) == kDaylight

                || ((duplicatedTimeOpt & kStdDstMask) != kStandard && (duplicatedTimeOpt & kFormerLatterMask) == kFormer)) {

            date -= getDSTSavings();

            recalc = TRUE;

        }

    }

    if (recalc) {

        day = uprv_floor(date / U_MILLIS_PER_DAY);

        millis = (int32_t) (date - day * U_MILLIS_PER_DAY);

        Grego::dayToFields(day, year, month, dom, dow);

        savingsDST = getOffset(GregorianCalendar::AD, year, month, dom,

                          (uint8_t) dow, millis,

                          Grego::monthLength(year, month),

                          status) - rawOffsetGMT;

    }

}

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

/**

 * Compare a given date in the year to a rule. Return 1, 0, or -1, depending

 * on whether the date is after, equal to, or before the rule date. The

 * millis are compared directly against the ruleMillis, so any

 * standard-daylight adjustments must be handled by the caller.

 *

 * @return  1 if the date is after the rule date, -1 if the date is before

 *          the rule date, or 0 if the date is equal to the rule date.

 */

int32_t 

SimpleTimeZone::compareToRule(int8_t month, int8_t monthLen, int8_t prevMonthLen,

                              int8_t dayOfMonth,

                              int8_t dayOfWeek, int32_t millis, int32_t millisDelta,

                              EMode ruleMode, int8_t ruleMonth, int8_t ruleDayOfWeek,

                              int8_t ruleDay, int32_t ruleMillis)

{

    // Make adjustments for startTimeMode and endTimeMode

    millis += millisDelta;

    while (millis >= U_MILLIS_PER_DAY) {

        millis -= U_MILLIS_PER_DAY;

        ++dayOfMonth;

        dayOfWeek = (int8_t)(1 + (dayOfWeek % 7)); // dayOfWeek is one-based

        if (dayOfMonth > monthLen) {

            dayOfMonth = 1;

            /* When incrementing the month, it is desirable to overflow

             * from DECEMBER to DECEMBER+1, since we use the result to

             * compare against a real month. Wraparound of the value

             * leads to bug 4173604. */

            ++month;

        }

    }

    while (millis < 0) {

        millis += U_MILLIS_PER_DAY;

        --dayOfMonth;

        dayOfWeek = (int8_t)(1 + ((dayOfWeek+5) % 7)); // dayOfWeek is one-based

        if (dayOfMonth < 1) {

            dayOfMonth = prevMonthLen;

            --month;

        }

    }

    // first compare months.  If they're different, we don't have to worry about days

    // and times

    if (month < ruleMonth) return -1;

    else if (month > ruleMonth) return 1;

    // calculate the actual day of month for the rule

    int32_t ruleDayOfMonth = 0;

    // Adjust the ruleDay to the monthLen, for non-leap year February 29 rule days.

    if (ruleDay > monthLen) {

        ruleDay = monthLen;

    }

    switch (ruleMode)

    {

    // if the mode is day-of-month, the day of month is given

    case DOM_MODE:

        ruleDayOfMonth = ruleDay;

        break;

    // if the mode is day-of-week-in-month, calculate the day-of-month from it

    case DOW_IN_MONTH_MODE:

        // In this case ruleDay is the day-of-week-in-month (this code is using

        // the dayOfWeek and dayOfMonth parameters to figure out the day-of-week

        // of the first day of the month, so it's trusting that they're really

        // consistent with each other)

        if (ruleDay > 0)

            ruleDayOfMonth = 1 + (ruleDay - 1) * 7 +

                (7 + ruleDayOfWeek - (dayOfWeek - dayOfMonth + 1)) % 7;

        // if ruleDay is negative (we assume it's not zero here), we have to do

        // the same calculation figuring backward from the last day of the month.

        else

        {

            // (again, this code is trusting that dayOfWeek and dayOfMonth are

            // consistent with each other here, since we're using them to figure

            // the day of week of the first of the month)

            ruleDayOfMonth = monthLen + (ruleDay + 1) * 7 -

                (7 + (dayOfWeek + monthLen - dayOfMonth) - ruleDayOfWeek) % 7;

        }

        break;

    case DOW_GE_DOM_MODE:

        ruleDayOfMonth = ruleDay +

            (49 + ruleDayOfWeek - ruleDay - dayOfWeek + dayOfMonth) % 7;

        break;

    case DOW_LE_DOM_MODE:

        ruleDayOfMonth = ruleDay -

            (49 - ruleDayOfWeek + ruleDay + dayOfWeek - dayOfMonth) % 7;

        // Note at this point ruleDayOfMonth may be <1, although it will

        // be >=1 for well-formed rules.

        break;

    }

    // now that we have a real day-in-month for the rule, we can compare days...

    if (dayOfMonth < ruleDayOfMonth) return -1;

    else if (dayOfMonth > ruleDayOfMonth) return 1;

    // ...and if they're equal, we compare times

    if (millis < ruleMillis) return -1;

    else if (millis > ruleMillis) return 1;

    else return 0;

}

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

int32_t

SimpleTimeZone::getRawOffset() const

{

    return rawOffset;

}

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

void

SimpleTimeZone::setRawOffset(int32_t offsetMillis)

{

    rawOffset = offsetMillis;

    transitionRulesInitialized = FALSE;

}

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

void 

SimpleTimeZone::setDSTSavings(int32_t millisSavedDuringDST, UErrorCode& status) 

{

    if (millisSavedDuringDST == 0) {

        status = U_ILLEGAL_ARGUMENT_ERROR;

    }

    else {

        dstSavings = millisSavedDuringDST;

    }

    transitionRulesInitialized = FALSE;

}

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

int32_t 

SimpleTimeZone::getDSTSavings() const

{

    return dstSavings;

}

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

UBool

SimpleTimeZone::useDaylightTime() const

{

    return useDaylight;

}

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

/**

 * Overrides TimeZone

 * Queries if the given date is in Daylight Savings Time.

 */

UBool SimpleTimeZone::inDaylightTime(UDate date, UErrorCode& status) const

{

    // This method is wasteful since it creates a new GregorianCalendar and

    // deletes it each time it is called.  However, this is a deprecated method

    // and provided only for Java compatibility as of 8/6/97 [LIU].

    if (U_FAILURE(status)) return FALSE;

    GregorianCalendar *gc = new GregorianCalendar(*this, status);

    /* test for NULL */

    if (gc == 0) {

        status = U_MEMORY_ALLOCATION_ERROR;

        return FALSE;

    }

    gc->setTime(date, status);

    UBool result = gc->inDaylightTime(status);

    delete gc;

    return result;

}

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

/**

 * Return true if this zone has the same rules and offset as another zone.

 * @param other the TimeZone object to be compared with

 * @return true if the given zone has the same rules and offset as this one

 */

UBool 

SimpleTimeZone::hasSameRules(const TimeZone& other) const

{

    if (this == &other) return TRUE;

    if (typeid(*this) != typeid(other)) return FALSE;

    SimpleTimeZone *that = (SimpleTimeZone*)&other;

    return rawOffset     == that->rawOffset &&

        useDaylight     == that->useDaylight &&

        (!useDaylight

         // Only check rules if using DST

         || (dstSavings     == that->dstSavings &&

             startMode      == that->startMode &&

             startMonth     == that->startMonth &&

             startDay       == that->startDay &&

             startDayOfWeek == that->startDayOfWeek &&

             startTime      == that->startTime &&

             startTimeMode  == that->startTimeMode &&

             endMode        == that->endMode &&

             endMonth       == that->endMonth &&

             endDay         == that->endDay &&

             endDayOfWeek   == that->endDayOfWeek &&

             endTime        == that->endTime &&

             endTimeMode    == that->endTimeMode &&

             startYear      == that->startYear));

}

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

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

// Rule representation

//

// We represent the following flavors of rules:

//       5        the fifth of the month

//       lastSun  the last Sunday in the month

//       lastMon  the last Monday in the month

//       Sun>=8   first Sunday on or after the eighth

//       Sun<=25  last Sunday on or before the 25th

// This is further complicated by the fact that we need to remain

// backward compatible with the 1.1 FCS.  Finally, we need to minimize

// API changes.  In order to satisfy these requirements, we support

// three representation systems, and we translate between them.

//

// INTERNAL REPRESENTATION

// This is the format SimpleTimeZone objects take after construction or

// streaming in is complete.  Rules are represented directly, using an

// unencoded format.  We will discuss the start rule only below; the end

// rule is analogous.

//   startMode      Takes on enumerated values DAY_OF_MONTH,

//                  DOW_IN_MONTH, DOW_AFTER_DOM, or DOW_BEFORE_DOM.

//   startDay       The day of the month, or for DOW_IN_MONTH mode, a

//                  value indicating which DOW, such as +1 for first,

//                  +2 for second, -1 for last, etc.

//   startDayOfWeek The day of the week.  Ignored for DAY_OF_MONTH.

//

// ENCODED REPRESENTATION

// This is the format accepted by the constructor and by setStartRule()

// and setEndRule().  It uses various combinations of positive, negative,

// and zero values to encode the different rules.  This representation

// allows us to specify all the different rule flavors without altering

// the API.

//   MODE              startMonth    startDay    startDayOfWeek

//   DOW_IN_MONTH_MODE >=0           !=0         >0

//   DOM_MODE          >=0           >0          ==0

//   DOW_GE_DOM_MODE   >=0           >0          <0

//   DOW_LE_DOM_MODE   >=0           <0          <0

//   (no DST)          don't care    ==0         don't care

//

// STREAMED REPRESENTATION

// We must retain binary compatibility with the 1.1 FCS.  The 1.1 code only

// handles DOW_IN_MONTH_MODE and non-DST mode, the latter indicated by the

// flag useDaylight.  When we stream an object out, we translate into an

// approximate DOW_IN_MONTH_MODE representation so the object can be parsed

// and used by 1.1 code.  Following that, we write out the full

// representation separately so that contemporary code can recognize and

// parse it.  The full representation is written in a "packed" format,

// consisting of a version number, a length, and an array of bytes.  Future

// versions of this class may specify different versions.  If they wish to

// include additional data, they should do so by storing them after the

// packed representation below.

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

/**

 * Given a set of encoded rules in startDay and startDayOfMonth, decode

 * them and set the startMode appropriately.  Do the same for endDay and

 * endDayOfMonth.  Upon entry, the day of week variables may be zero or

 * negative, in order to indicate special modes.  The day of month

 * variables may also be negative.  Upon exit, the mode variables will be

 * set, and the day of week and day of month variables will be positive.

 * This method also recognizes a startDay or endDay of zero as indicating

 * no DST.

 */

void 

SimpleTimeZone::decodeRules(UErrorCode& status)

{

    decodeStartRule(status);

    decodeEndRule(status);

}

/**

 * Decode the start rule and validate the parameters.  The parameters are

 * expected to be in encoded form, which represents the various rule modes

 * by negating or zeroing certain values.  Representation formats are:

 * <p>

 * <pre>

 *            DOW_IN_MONTH  DOM    DOW>=DOM  DOW<=DOM  no DST

 *            ------------  -----  --------  --------  ----------

 * month       0..11        same    same      same     don't care

 * day        -5..5         1..31   1..31    -1..-31   0

 * dayOfWeek   1..7         0      -1..-7    -1..-7    don't care

 * time        0..ONEDAY    same    same      same     don't care

 * </pre>

 * The range for month does not include UNDECIMBER since this class is

 * really specific to GregorianCalendar, which does not use that month.

 * The range for time includes ONEDAY (vs. ending at ONEDAY-1) because the

 * end rule is an exclusive limit point.  That is, the range of times that

 * are in DST include those >= the start and < the end.  For this reason,

 * it should be possible to specify an end of ONEDAY in order to include the

 * entire day.  Although this is equivalent to time 0 of the following day,

 * it's not always possible to specify that, for example, on December 31.

 * While arguably the start range should still be 0..ONEDAY-1, we keep

 * the start and end ranges the same for consistency.

 */

void 

SimpleTimeZone::decodeStartRule(UErrorCode& status) 

{

    if(U_FAILURE(status)) return;

    useDaylight = (UBool)((startDay != 0) && (endDay != 0) ? TRUE : FALSE);

    if (useDaylight && dstSavings == 0) {

        dstSavings = U_MILLIS_PER_HOUR;

    }

    if (startDay != 0) {

        if (startMonth < UCAL_JANUARY || startMonth > UCAL_DECEMBER) {

            status = U_ILLEGAL_ARGUMENT_ERROR;

            return;

        }

        if (startTime < 0 || startTime > U_MILLIS_PER_DAY ||

            startTimeMode < WALL_TIME || startTimeMode > UTC_TIME) {

            status = U_ILLEGAL_ARGUMENT_ERROR;

            return;

        }

        if (startDayOfWeek == 0) {

            startMode = DOM_MODE;

        } else {

            if (startDayOfWeek > 0) {

                startMode = DOW_IN_MONTH_MODE;

            } else {

                startDayOfWeek = (int8_t)-startDayOfWeek;

                if (startDay > 0) {

                    startMode = DOW_GE_DOM_MODE;

                } else {

                    startDay = (int8_t)-startDay;

                    startMode = DOW_LE_DOM_MODE;

                }

            }

            if (startDayOfWeek > UCAL_SATURDAY) {

                status = U_ILLEGAL_ARGUMENT_ERROR;

                return;

            }

        }

        if (startMode == DOW_IN_MONTH_MODE) {

            if (startDay < -5 || startDay > 5) {

                status = U_ILLEGAL_ARGUMENT_ERROR;

                return;

            }

        } else if (startDay<1 || startDay > STATICMONTHLENGTH[startMonth]) {

            status = U_ILLEGAL_ARGUMENT_ERROR;

            return;

        }

    }

}

/**

 * Decode the end rule and validate the parameters.  This method is exactly

 * analogous to decodeStartRule().

 * @see decodeStartRule

 */

void 

SimpleTimeZone::decodeEndRule(UErrorCode& status) 

{

    if(U_FAILURE(status)) return;

    useDaylight = (UBool)((startDay != 0) && (endDay != 0) ? TRUE : FALSE);

    if (useDaylight && dstSavings == 0) {

        dstSavings = U_MILLIS_PER_HOUR;

    }

    if (endDay != 0) {

        if (endMonth < UCAL_JANUARY || endMonth > UCAL_DECEMBER) {

            status = U_ILLEGAL_ARGUMENT_ERROR;

            return;

        }

        if (endTime < 0 || endTime > U_MILLIS_PER_DAY ||

            endTimeMode < WALL_TIME || endTimeMode > UTC_TIME) {

            status = U_ILLEGAL_ARGUMENT_ERROR;

            return;

        }

        if (endDayOfWeek == 0) {

            endMode = DOM_MODE;

        } else {

            if (endDayOfWeek > 0) {

                endMode = DOW_IN_MONTH_MODE;

            } else {

                endDayOfWeek = (int8_t)-endDayOfWeek;

                if (endDay > 0) {