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Diffstat (limited to 'kstars/kstars/timezonerule.h')
| -rw-r--r-- | kstars/kstars/timezonerule.h | 171 |
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diff --git a/kstars/kstars/timezonerule.h b/kstars/kstars/timezonerule.h new file mode 100644 index 00000000..c24f7243 --- /dev/null +++ b/kstars/kstars/timezonerule.h @@ -0,0 +1,171 @@ +/*************************************************************************** + timezonerule.h - description + ------------------- + begin : Tue Apr 2 2002 + copyright : (C) 2002 by Jason Harris + email : kstars@30doradus.org + ***************************************************************************/ + +/*************************************************************************** + * * + * This program is free software; you can redistribute it and/or modify * + * it under the terms of the GNU General Public License as published by * + * the Free Software Foundation; either version 2 of the License, or * + * (at your option) any later version. * + * * + ***************************************************************************/ + +#ifndef TIMEZONERULE_H +#define TIMEZONERULE_H + +/**@class TimeZoneRule + *This class provides the information needed to determine whether Daylight + *Savings Time (DST; a.k.a. "Summer Time") is currently active at a given + *location. There are (at least) 25 different "rules" which govern DST + *around the world; a string identifying the appropriate rule is attachded + *to each city in Cities.dat. + * + *The rules themselves are stored in the TZrulebook.dat file, which is read + *on startup; each line in the file creates a TimeZoneRule object. + * + *TimeZoneRule consists of QStrings identifying the months and days on which + *DST starts and ends, QTime objects identifying the time at which the + *changes occur, and a double indicating the size of the offset in hours + *(probably always 1.00). + * + *Month names should be the English three-letter abbreviation, uncapitalized. + *Day names are either an integer indicating the calendar date (i.e., "15" is + *the fifteenth of the month), or a number paired with a three-letter + *abbreviation for a weekday. This indicates the Nth weekday of the month + *(i.e., "2sun" is the second Sunday of the Month). Finally, the weekday + *string on its own indicates the last weekday of the month (i.e., + *"mon" is the last Monday of the month). + * + *The isDSTActive(KStarsDateTime) function returns true if DST is active for the + *DateTime given as an argument. + * + *The nextDSTChange(KStarsDateTime) function returns the KStarsDateTime of the moment + *at which the next DST change will occur for the current location. + *@author Jason Harris + *@version 1.0 + */ + +#include <qstring.h> +#include "kstarsdatetime.h" + +class TimeZoneRule { +public: + /**Default Constructor. Makes the "empty" time zone rule (i.e., no DST correction)*/ + TimeZoneRule(); + + /**Constructor. Create a TZ rule according to the arguments. + *@p smonth the three-letter code for the month in which DST starts + *@p sday a string encoding the day on which DST starts (see the class description) + *@p stime the time at which DST starts + *@p rmonth the three-letter code for the month in which DST reverts + *@p rday a string encoding the day on which DST reverts (see the class description) + *@p rtime the time at which DST reverts + *@p offset the offset between normal time and DS time (always 1.00?) + */ + TimeZoneRule( const QString &smonth, const QString &sday, const QTime &stime, + const QString &rmonth, const QString &rday, const QTime &rtime, const double &offset=1.00 ); + + /**Destructor. (empty)*/ + ~TimeZoneRule(); + + /**Determine whether DST is in effect for the given DateTime, according to this rule + *@p date the date/time to test for DST + */ + bool isDSTActive( const KStarsDateTime &date ); + + /**@return TRUE if the rule is the "empty" TZ rule. */ + bool isEmptyRule() { return ( HourOffset == 0.0 ); } + + /** Toggle DST on/off. The @p activate argument should probably be isDSTActive() + *@param activate if TRUE, then set DST active; otherwise, deactivate DST + */ + void setDST( bool activate=true ); + + /**@return the current Timezone offset, compared to the timezone's Standard Time. + *This is typically 0.0 if DST is inactive, and 1.0 if DST is active. */ + double deltaTZ() const { return dTZ; } + +/** Recalculate next dst change and if DST is active by a given local time with + *timezone offset and time direction. + *@param ltime the time to be tested + *@param time_runs_forward time direction + *@param TZoffset offset of timezone in some fictional unit + *@param automaticDSTchange is automatic DST change? + * + * @todo Check dox for TZoffset + */ + void reset_with_ltime( KStarsDateTime <ime, const double TZoffset, const bool time_runs_forward, + const bool automaticDSTchange = false ); + + /**@return computed value for next DST change in universal time. + */ + KStarsDateTime nextDSTChange() { return next_change_utc; } + + /**@return computed value for next DST change in local time. + */ + KStarsDateTime nextDSTChange_LTime() { return next_change_ltime; } + + /**@return TRUE if this rule is the same as the argument. + *@p r the rule to check for equivalence + */ + bool equals( TimeZoneRule *r ); + + int StartMonth, RevertMonth; + +private: + + /**@return the KStarsDateTime of the moment when the next DST change will occur in local time + *This is useful because DST change times are saved in local times*/ + void nextDSTChange_LTime( const KStarsDateTime &date ); + + /**@return the KStarsDateTime of the moment when the last DST change occurred in local time + *This is useful because DST change times are saved in local times + *We need this in case time is running backwards. */ + void previousDSTChange_LTime( const KStarsDateTime &date ); + + /**calculate the next DST change in universal time for current location */ + void nextDSTChange( const KStarsDateTime &local_date, const double TZoffset ); + + /**calculate the previous DST change in universal time for current location */ + void previousDSTChange( const KStarsDateTime &local_date, const double TZoffset ); + + /**Interpret the string as a month of the year; + *@return the month integer (1=jan ... 12=dec) + */ + int initMonth( const QString &m ); + + /**Interpret the day string as a week ID and a day-of-week ID. The day-of-week + *is an integer between 1 (sunday) and 7 (saturday); the week integer can + *be 1-3 (1st/2nd/third weekday of the month), or 5 (last weekday of the month) + *@p day the day integer is returned by reference through this value + *@p week the week integer is returned by reference through this value + *@return TRUE if the day string was successfully parsed + */ + bool initDay( const QString &d, int &day, int &week ); + + /**Find the calendar date on which DST starts for the calendar year + *of the given KStarsDateTime. + *@p d the date containing the year to be tested + *@return the calendar date, an integer between 1 and 31. */ + int findStartDay( const KStarsDateTime &d ); + + /**Find the calendar date on which DST ends for the calendar year + *of the given KStarsDateTime. + *@p d the date containing the year to be tested + *@return the calendar date, an integer between 1 and 31. */ + int findRevertDay( const KStarsDateTime &d ); + + int StartDay, RevertDay; + int StartWeek, RevertWeek; + QTime StartTime, RevertTime; + KStarsDateTime next_change_utc, next_change_ltime; + double dTZ, HourOffset; + +}; + +#endif |