gecko-dev/modules/libnls/headers/simpletz.h
1998-05-27 02:02:27 +00:00

363 lines
16 KiB
C++

/*
********************************************************************************
* *
* COPYRIGHT: *
* (C) Copyright Taligent, Inc., 1997 *
* (C) Copyright International Business Machines Corporation, 1997 *
* Licensed Material - Program-Property of IBM - All Rights Reserved. *
* US Government Users Restricted Rights - Use, duplication, or disclosure *
* restricted by GSA ADP Schedule Contract with IBM Corp. *
* *
********************************************************************************
*
* File SIMPLETZ.H
*
* Modification History:
*
* Date Name Description
* 04/21/97 aliu Overhauled header.
********************************************************************************
*/
#ifndef _SIMPLETZ
#define _SIMPLETZ
#include "timezone.h"
/**
* <code>SimpleTimeZone</code> is a concrete subclass of <code>TimeZone</code>
* that represents a time zone for use with a Gregorian calendar. This
* class does not handle historical changes.
* <P>
* When specifying daylight-savings-time begin and end dates, use a negative value for
* <code>dayOfWeekInMonth</code> to indicate that <code>SimpleTimeZone</code> should
* count from the end of the month backwards. For example, in the U.S., Daylight Savings
* Time ends at the last (dayOfWeekInMonth = -1) Sunday in October, at 2 AM in standard
* time.
*
* @see Calendar
* @see GregorianCalendar
* @see TimeZone
* @version 1.24 10/30/97
* @author David Goldsmith, Mark Davis, Chen-Lieh Huang, Alan Liu
*/
#ifdef NLS_MAC
#pragma export on
#endif
class T_FORMAT_API SimpleTimeZone: public TimeZone {
public:
/**
* Need default constructor for some UNIX platforms
*/
SimpleTimeZone(void);
/**
* Copy constructor
*/
SimpleTimeZone(const SimpleTimeZone& source);
/**
* Default assignment operator
*/
SimpleTimeZone& operator=(const SimpleTimeZone& right);
/**
* Destructor
*/
virtual ~SimpleTimeZone();
/**
* Returns true if the two TimeZone objects are equal; that is, they have
* the same ID, raw GMT offset, and DST rules.
*
* @param that The SimpleTimeZone object to be compared with.
* @return True if the given time zone is equal to this time zone; false
* otherwise.
*/
virtual t_bool operator==(const TimeZone& that) const;
/**
* Constructs a SimpleTimeZone with the given raw GMT offset and time zone ID,
* and which doesn't observe daylight savings time. Normally you should use
* TimeZone::createInstance() to create a TimeZone instead of creating a
* SimpleTimeZone directly with this constructor.
*
* @param rawOffset The given base time zone offset to GMT.
* @param ID The timezone ID which is obtained from
* TimeZone.getAvailableIDs.
*/
SimpleTimeZone(t_int32 rawOffset, const UnicodeString& ID);
/**
* Construct a SimpleTimeZone with the given raw GMT offset, time zone ID,
* and times to start and end daylight savings time. To create a TimeZone that
* doesn't observe daylight savings time, don't use this constructor; use
* SimpleTimeZone(rawOffset, ID) instead. Normally, you should use
* TimeZone.createInstance() to create a TimeZone instead of creating a
* SimpleTimeZone directly with this constructor.
* <P>
* Various types of daylight-savings time rules can be specfied by using different
* values for startDay and startDayOfWeek and endDay and endDayOfWeek. For a
* complete explanation of how these parameters work, see the documentation for
* setStartRule().
*
* @param rawOffset The new SimpleTimeZone's raw GMT offset
* @param ID The new SimpleTimeZone's time zone ID.
* @param startMonth The daylight savings starting month. Month is
* 0-based. eg, 0 for January.
* @param startDay The daylight savings starting
* day-of-week-in-month. See setStartRule() for a
* complete explanation.
* @param startDayOfWeek The daylight savings starting day-of-week. See setStartRule()
* for a complete explanation.
* @param startTime The daylight savings starting time, expressed as the
* number of milliseconds after midnight.
* @param endMonth The daylight savings ending month. Month is
* 0-based. eg, 0 for January.
* @param endDay The daylight savings ending day-of-week-in-month.
* See setStartRule() for a complete explanation.
* @param endDayOfWeek The daylight savings ending day-of-week. See setStartRule()
* for a complete explanation.
* @param endTime The daylight savings ending time, expressed as the
* number of milliseconds after midnight.
* @param dstSavings The number of milliseconds to add to the raw GMT offset
* when daylight savings time is in effect. (e.g., in the
* U.S. daylight savings time shifts the time forward one
* hour.) Defaults to plus one hour.
*/
SimpleTimeZone(t_int32 rawOffset, const UnicodeString& ID,
t_int8 startMonth, t_int8 startDayOfWeekInMonth,
t_int8 startDayOfWeek, t_int32 startTime,
t_int8 endMonth, t_int8 endDayOfWeekInMonth,
t_int8 endDayOfWeek, t_int32 endTime,
t_int32 dstSavings = kMillisPerHour);
/**
* 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 setStartYear(t_int32 year);
/**
* 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 specfied 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 setStartRule(int month, int dayOfWeekInMonth, int dayOfWeek,
t_int32 time);
/**
* 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:
* <pre>
* . setEndRule(TimeFields.OCTOBER, -1, TimeFields.SUNDAY, 2*60*60*1000);
* </pre>
* 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 setEndRule(int month, int dayOfWeekInMonth, int dayOfWeek,
t_int32 time);
/**
* Returns the TimeZone's adjusted GMT offset (i.e., the number of milliseconds to add
* to GMT to get local time in this time zone, taking daylight savings time into
* account) as of a particular reference date. The reference date is used to determine
* whether daylight savings time is in effect and needs to be figured into the offset
* that is returned (in other words, what is the adjusted GMT offset in this time zone
* at this particular date and time?).
* <P>
* For the time zones produced by createTimeZone(),
* the reference data is specified according to the Gregorian calendar, and the date
* and time fields are in GMT, NOT local time.
*
* @param era The reference date's era
* @param year The reference date's year
* @param month The reference date's month (0-based; 0 is January)
* @param day The reference date's day-in-month (1-based)
* @param dayOfWeek The reference date's day-of-week (1-based; 1 is Sunday)
* @param millis The reference date's milliseconds in day, UTT (NOT local time).
* @return The offset in milliseconds to add to GMT to get local time.
*/
virtual t_int32 getOffset(t_uint8 era, t_int32 year, t_int32 month, t_int32 day,
t_uint8 dayOfWeek, t_int32 millis) const;
/**
* Returns the TimeZone's raw GMT offset (i.e., the number of milliseconds to add
* to GMT to get local time, before taking daylight savings time into account).
*
* @return The TimeZone's raw GMT offset.
*/
virtual t_int32 getRawOffset() const;
/**
* Sets the TimeZone's raw GMT offset (i.e., the number of milliseconds to add
* to GMT to get local time, before taking daylight savings time into account).
*
* @param offsetMillis The new raw GMT offset for this time zone.
*/
virtual void setRawOffset(t_int32 offsetMillis);
/**
* Queries if this TimeZone uses Daylight Savings Time.
*
* @return True if this TimeZone uses Daylight Savings Time; false otherwise.
*/
virtual t_bool useDaylightTime() const;
/**
* Returns true if the given date is within the period when daylight savings time
* is in effect; false otherwise. If the TimeZone doesn't observe daylight savings
* time, this functions always returns false.
* @param date The date to test.
* @return true if the given date is in Daylight Savings Time;
* false otherwise.
*/
virtual t_bool inDaylightTime(Date date, ErrorCode& status) const;
/**
* Clones TimeZone objects polymorphically. Clients are responsible for deleting
* the TimeZone object cloned.
*
* @return A new copy of this TimeZone object.
*/
virtual TimeZone* clone() const;
public:
/**
* Override TimeZone Returns a unique class ID POLYMORPHICALLY. Pure virtual
* override. This method is to implement a simple version of RTTI, since not all C++
* compilers support genuine RTTI. Polymorphic operator==() and clone() methods call
* this method.
*
* @return The class ID for this object. All objects of a given class have the
* same class ID. Objects of other classes have different class IDs.
*/
virtual ClassID getDynamicClassID() const { return (ClassID)&fgClassID; }
/**
* Return the class ID for this class. This is useful only for comparing to a return
* value from getDynamicClassID(). For example:
* <pre>
* . Base* polymorphic_pointer = createPolymorphicObject();
* . if (polymorphic_pointer->getDynamicClassID() ==
* . Derived::getStaticClassID()) ...
* </pre>
* @return The class ID for all objects of this class.
*/
static ClassID getStaticClassID() { return (ClassID)&fgClassID; }
private:
/**
* Constants specifying values of startMode and endMode.
*/
enum EMode
{
DOM_MODE = 1,
DOW_IN_MONTH_MODE,
DOW_GE_DOM_MODE,
DOW_LE_DOM_MODE
};
/**
* 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. Assume that
* no rule references the end of February (e.g., last Sunday in February).
*
* @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.
*/
static int compareToRule(int month, int dayOfMonth, int dayOfWeek, t_int32 millis,
EMode ruleMode, int ruleMonth, int ruleDayOfWeek,
int ruleDay, t_int32 ruleMillis);
/**
* Given a set of encoded rules in startDay and startDayOfMonth, decode
* them and set the startMode appropriately. Do the same for endDay and
* endDayOfMonth.
* <P>
* 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.
* <P>
* Upon exit, the mode variables will be
* set, and the day of week and day of month variables will be positive.
* <P>
* This method also recognizes a startDay or endDay of zero as indicating
* no DST.
*/
void decodeRules();
static char fgClassID;
int startMonth, startDay, startDayOfWeek; // the month, day, DOW, and time DST starts
t_int32 startTime;
int endMonth, endDay, endDayOfWeek; // the month, day, DOW, and time DST ends
t_int32 endTime;
int startYear; // the year these DST rules took effect
t_int32 rawOffset; // the TimeZone's raw GMT offset
t_bool useDaylight; // flag indicating whether this TimeZone uses DST
static t_int32 millisPerHour; // number of millis in an hour
static const t_uint8 staticMonthLength[12]; // lengths of the months
EMode startMode, endMode; // flags indicating what kind of rules the DST rules are
/**
* A positive value indicating the amount of time saved during DST in ms.
* Typically one hour; sometimes 30 minutes.
*/
t_int32 dstSavings;
};
#ifdef NLS_MAC
#pragma export off
#endif
#endif // _SIMPLETZ