michael@0: /*
michael@0:  **********************************************************************
michael@0:  * Copyright (c) 2003-2008, International Business Machines
michael@0:  * Corporation and others.  All Rights Reserved.
michael@0:  **********************************************************************
michael@0:  * Author: Alan Liu
michael@0:  * Created: September 2 2003
michael@0:  * Since: ICU 2.8
michael@0:  **********************************************************************
michael@0:  */
michael@0: 
michael@0: #ifndef GREGOIMP_H
michael@0: #define GREGOIMP_H
michael@0: #include "unicode/utypes.h"
michael@0: #if !UCONFIG_NO_FORMATTING
michael@0: 
michael@0: #include "unicode/ures.h"
michael@0: #include "unicode/locid.h"
michael@0: #include "putilimp.h"
michael@0: 
michael@0: U_NAMESPACE_BEGIN
michael@0: 
michael@0: /**
michael@0:  * A utility class providing mathematical functions used by time zone
michael@0:  * and calendar code.  Do not instantiate.  Formerly just named 'Math'.
michael@0:  * @internal
michael@0:  */
michael@0: class ClockMath {
michael@0:  public:
michael@0:     /**
michael@0:      * Divide two integers, returning the floor of the quotient.
michael@0:      * Unlike the built-in division, this is mathematically
michael@0:      * well-behaved.  E.g., <code>-1/4</code> => 0 but
michael@0:      * <code>floorDivide(-1,4)</code> => -1.
michael@0:      * @param numerator the numerator
michael@0:      * @param denominator a divisor which must be != 0
michael@0:      * @return the floor of the quotient
michael@0:      */
michael@0:     static int32_t floorDivide(int32_t numerator, int32_t denominator);
michael@0: 
michael@0:     /**
michael@0:      * Divide two numbers, returning the floor of the quotient.
michael@0:      * Unlike the built-in division, this is mathematically
michael@0:      * well-behaved.  E.g., <code>-1/4</code> => 0 but
michael@0:      * <code>floorDivide(-1,4)</code> => -1.
michael@0:      * @param numerator the numerator
michael@0:      * @param denominator a divisor which must be != 0
michael@0:      * @return the floor of the quotient
michael@0:      */
michael@0:     static inline double floorDivide(double numerator, double denominator);
michael@0: 
michael@0:     /**
michael@0:      * Divide two numbers, returning the floor of the quotient and
michael@0:      * the modulus remainder.  Unlike the built-in division, this is
michael@0:      * mathematically well-behaved.  E.g., <code>-1/4</code> => 0 and
michael@0:      * <code>-1%4</code> => -1, but <code>floorDivide(-1,4)</code> =>
michael@0:      * -1 with <code>remainder</code> => 3.  NOTE: If numerator is
michael@0:      * too large, the returned quotient may overflow.
michael@0:      * @param numerator the numerator
michael@0:      * @param denominator a divisor which must be != 0
michael@0:      * @param remainder output parameter to receive the
michael@0:      * remainder. Unlike <code>numerator % denominator</code>, this
michael@0:      * will always be non-negative, in the half-open range <code>[0,
michael@0:      * |denominator|)</code>.
michael@0:      * @return the floor of the quotient
michael@0:      */
michael@0:     static int32_t floorDivide(double numerator, int32_t denominator,
michael@0:                                int32_t& remainder);
michael@0: 
michael@0:     /**
michael@0:      * For a positive divisor, return the quotient and remainder
michael@0:      * such that dividend = quotient*divisor + remainder and
michael@0:      * 0 <= remainder < divisor.
michael@0:      *
michael@0:      * Works around edge-case bugs.  Handles pathological input
michael@0:      * (divident >> divisor) reasonably.
michael@0:      *
michael@0:      * Calling with a divisor <= 0 is disallowed.
michael@0:      */
michael@0:     static double floorDivide(double dividend, double divisor,
michael@0:                               double& remainder);
michael@0: };
michael@0: 
michael@0: // Useful millisecond constants
michael@0: #define kOneDay    (1.0 * U_MILLIS_PER_DAY)       //  86,400,000
michael@0: #define kOneHour   (60*60*1000)
michael@0: #define kOneMinute 60000
michael@0: #define kOneSecond 1000
michael@0: #define kOneMillisecond  1
michael@0: #define kOneWeek   (7.0 * kOneDay) // 604,800,000
michael@0: 
michael@0: // Epoch constants
michael@0: #define kJan1_1JulianDay  1721426 // January 1, year 1 (Gregorian)
michael@0: 
michael@0: #define kEpochStartAsJulianDay  2440588 // January 1, 1970 (Gregorian)
michael@0: 
michael@0: #define kEpochYear              1970
michael@0: 
michael@0: 
michael@0: #define kEarliestViableMillis  -185331720384000000.0  // minimum representable by julian day  -1e17
michael@0: 
michael@0: #define kLatestViableMillis     185753453990400000.0  // max representable by julian day      +1e17
michael@0: 
michael@0: /**
michael@0:  * The minimum supported Julian day.  This value is equivalent to
michael@0:  * MIN_MILLIS.
michael@0:  */
michael@0: #define MIN_JULIAN (-0x7F000000)
michael@0: 
michael@0: /**
michael@0:  * The minimum supported epoch milliseconds.  This value is equivalent
michael@0:  * to MIN_JULIAN.
michael@0:  */
michael@0: #define MIN_MILLIS ((MIN_JULIAN - kEpochStartAsJulianDay) * kOneDay)
michael@0: 
michael@0: /**
michael@0:  * The maximum supported Julian day.  This value is equivalent to
michael@0:  * MAX_MILLIS.
michael@0:  */
michael@0: #define MAX_JULIAN (+0x7F000000)
michael@0: 
michael@0: /**
michael@0:  * The maximum supported epoch milliseconds.  This value is equivalent
michael@0:  * to MAX_JULIAN.
michael@0:  */
michael@0: #define MAX_MILLIS ((MAX_JULIAN - kEpochStartAsJulianDay) * kOneDay)
michael@0: 
michael@0: /**
michael@0:  * A utility class providing proleptic Gregorian calendar functions
michael@0:  * used by time zone and calendar code.  Do not instantiate.
michael@0:  *
michael@0:  * Note:  Unlike GregorianCalendar, all computations performed by this
michael@0:  * class occur in the pure proleptic GregorianCalendar.
michael@0:  */
michael@0: class Grego {
michael@0:  public:
michael@0:     /**
michael@0:      * Return TRUE if the given year is a leap year.
michael@0:      * @param year Gregorian year, with 0 == 1 BCE, -1 == 2 BCE, etc.
michael@0:      * @return TRUE if the year is a leap year
michael@0:      */
michael@0:     static inline UBool isLeapYear(int32_t year);
michael@0: 
michael@0:     /**
michael@0:      * Return the number of days in the given month.
michael@0:      * @param year Gregorian year, with 0 == 1 BCE, -1 == 2 BCE, etc.
michael@0:      * @param month 0-based month, with 0==Jan
michael@0:      * @return the number of days in the given month
michael@0:      */
michael@0:     static inline int8_t monthLength(int32_t year, int32_t month);
michael@0: 
michael@0:     /**
michael@0:      * Return the length of a previous month of the Gregorian calendar.
michael@0:      * @param y the extended year
michael@0:      * @param m the 0-based month number
michael@0:      * @return the number of days in the month previous to the given month
michael@0:      */
michael@0:     static inline int8_t previousMonthLength(int y, int m);
michael@0: 
michael@0:     /**
michael@0:      * Convert a year, month, and day-of-month, given in the proleptic
michael@0:      * Gregorian calendar, to 1970 epoch days.
michael@0:      * @param year Gregorian year, with 0 == 1 BCE, -1 == 2 BCE, etc.
michael@0:      * @param month 0-based month, with 0==Jan
michael@0:      * @param dom 1-based day of month
michael@0:      * @return the day number, with day 0 == Jan 1 1970
michael@0:      */
michael@0:     static double fieldsToDay(int32_t year, int32_t month, int32_t dom);
michael@0:     
michael@0:     /**
michael@0:      * Convert a 1970-epoch day number to proleptic Gregorian year,
michael@0:      * month, day-of-month, and day-of-week.
michael@0:      * @param day 1970-epoch day (integral value)
michael@0:      * @param year output parameter to receive year
michael@0:      * @param month output parameter to receive month (0-based, 0==Jan)
michael@0:      * @param dom output parameter to receive day-of-month (1-based)
michael@0:      * @param dow output parameter to receive day-of-week (1-based, 1==Sun)
michael@0:      * @param doy output parameter to receive day-of-year (1-based)
michael@0:      */
michael@0:     static void dayToFields(double day, int32_t& year, int32_t& month,
michael@0:                             int32_t& dom, int32_t& dow, int32_t& doy);
michael@0: 
michael@0:     /**
michael@0:      * Convert a 1970-epoch day number to proleptic Gregorian year,
michael@0:      * month, day-of-month, and day-of-week.
michael@0:      * @param day 1970-epoch day (integral value)
michael@0:      * @param year output parameter to receive year
michael@0:      * @param month output parameter to receive month (0-based, 0==Jan)
michael@0:      * @param dom output parameter to receive day-of-month (1-based)
michael@0:      * @param dow output parameter to receive day-of-week (1-based, 1==Sun)
michael@0:      */
michael@0:     static inline void dayToFields(double day, int32_t& year, int32_t& month,
michael@0:                                    int32_t& dom, int32_t& dow);
michael@0: 
michael@0:     /**
michael@0:      * Convert a 1970-epoch milliseconds to proleptic Gregorian year,
michael@0:      * month, day-of-month, and day-of-week, day of year and millis-in-day.
michael@0:      * @param time 1970-epoch milliseconds
michael@0:      * @param year output parameter to receive year
michael@0:      * @param month output parameter to receive month (0-based, 0==Jan)
michael@0:      * @param dom output parameter to receive day-of-month (1-based)
michael@0:      * @param dow output parameter to receive day-of-week (1-based, 1==Sun)
michael@0:      * @param doy output parameter to receive day-of-year (1-based)
michael@0:      * @param mid output parameter to recieve millis-in-day
michael@0:      */
michael@0:     static void timeToFields(UDate time, int32_t& year, int32_t& month,
michael@0:                             int32_t& dom, int32_t& dow, int32_t& doy, int32_t& mid);
michael@0: 
michael@0:     /**
michael@0:      * Return the day of week on the 1970-epoch day
michael@0:      * @param day the 1970-epoch day (integral value)
michael@0:      * @return the day of week
michael@0:      */
michael@0:     static int32_t dayOfWeek(double day);
michael@0: 
michael@0:     /**
michael@0:      * Returns the ordinal number for the specified day of week within the month.
michael@0:      * The valid return value is 1, 2, 3, 4 or -1.
michael@0:      * @param year Gregorian year, with 0 == 1 BCE, -1 == 2 BCE, etc.
michael@0:      * @param month 0-based month, with 0==Jan
michael@0:      * @param dom 1-based day of month
michael@0:      * @return The ordinal number for the specified day of week within the month
michael@0:      */
michael@0:     static int32_t dayOfWeekInMonth(int32_t year, int32_t month, int32_t dom);
michael@0: 
michael@0:     /**
michael@0:      * Converts Julian day to time as milliseconds.
michael@0:      * @param julian the given Julian day number.
michael@0:      * @return time as milliseconds.
michael@0:      * @internal
michael@0:      */
michael@0:     static inline double julianDayToMillis(int32_t julian);
michael@0: 
michael@0:     /**
michael@0:      * Converts time as milliseconds to Julian day.
michael@0:      * @param millis the given milliseconds.
michael@0:      * @return the Julian day number.
michael@0:      * @internal
michael@0:      */
michael@0:     static inline int32_t millisToJulianDay(double millis);
michael@0: 
michael@0:     /** 
michael@0:      * Calculates the Gregorian day shift value for an extended year.
michael@0:      * @param eyear Extended year 
michael@0:      * @returns number of days to ADD to Julian in order to convert from J->G
michael@0:      */
michael@0:     static inline int32_t gregorianShift(int32_t eyear);
michael@0: 
michael@0:  private:
michael@0:     static const int16_t DAYS_BEFORE[24];
michael@0:     static const int8_t MONTH_LENGTH[24];
michael@0: };
michael@0: 
michael@0: inline double ClockMath::floorDivide(double numerator, double denominator) {
michael@0:     return uprv_floor(numerator / denominator);
michael@0: }
michael@0: 
michael@0: inline UBool Grego::isLeapYear(int32_t year) {
michael@0:     // year&0x3 == year%4
michael@0:     return ((year&0x3) == 0) && ((year%100 != 0) || (year%400 == 0));
michael@0: }
michael@0: 
michael@0: inline int8_t
michael@0: Grego::monthLength(int32_t year, int32_t month) {
michael@0:     return MONTH_LENGTH[month + (isLeapYear(year) ? 12 : 0)];
michael@0: }
michael@0: 
michael@0: inline int8_t
michael@0: Grego::previousMonthLength(int y, int m) {
michael@0:   return (m > 0) ? monthLength(y, m-1) : 31;
michael@0: }
michael@0: 
michael@0: inline void Grego::dayToFields(double day, int32_t& year, int32_t& month,
michael@0:                                int32_t& dom, int32_t& dow) {
michael@0:   int32_t doy_unused;
michael@0:   dayToFields(day,year,month,dom,dow,doy_unused);
michael@0: }
michael@0: 
michael@0: inline double Grego::julianDayToMillis(int32_t julian)
michael@0: {
michael@0:   return (julian - kEpochStartAsJulianDay) * kOneDay;
michael@0: }
michael@0: 
michael@0: inline int32_t Grego::millisToJulianDay(double millis) {
michael@0:   return (int32_t) (kEpochStartAsJulianDay + ClockMath::floorDivide(millis, (double)kOneDay));
michael@0: }
michael@0: 
michael@0: inline int32_t Grego::gregorianShift(int32_t eyear) {
michael@0:   int32_t y = eyear-1;
michael@0:   int32_t gregShift = ClockMath::floorDivide(y, 400) - ClockMath::floorDivide(y, 100) + 2;
michael@0:   return gregShift;
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * This utility class provides convenient access to the data needed for a calendar. 
michael@0:  * @internal ICU 3.0
michael@0:  */
michael@0: class CalendarData : public UMemory {
michael@0: public: 
michael@0:     /**
michael@0:      * Construct a CalendarData from the given locale.
michael@0:      * @param loc locale to use. The 'calendar' keyword will be ignored.
michael@0:      * @param type calendar type. NULL indicates the gregorian calendar. 
michael@0:      * No default lookup is done.
michael@0:      * @param status error code
michael@0:      */
michael@0:     CalendarData(const Locale& loc, const char *type, UErrorCode& status);
michael@0: 
michael@0:     /**
michael@0:      * Load data for calendar. Note, this object owns the resources, do NOT call ures_close()!
michael@0:      * The ResourceBundle C++ API should NOT be used because it is too slow for a low level API.
michael@0:      *
michael@0:      * @param key Resource key to data
michael@0:      * @param status Error Status
michael@0:      * @internal
michael@0:      */
michael@0:     UResourceBundle* getByKey(const char *key, UErrorCode& status);
michael@0: 
michael@0:     /**
michael@0:      * Load data for calendar. Note, this object owns the resources, do NOT call ures_close()!
michael@0:      * There is an implicit key of 'format'
michael@0:      * data is located in:   "calendar/key/format/subKey"
michael@0:      * for example,  calendar/dayNames/format/abbreviated
michael@0:      * The ResourceBundle C++ API should NOT be used because it is too slow for a low level API.
michael@0:      *
michael@0:      * @param key Resource key to data
michael@0:      * @param subKey Resource key to data
michael@0:      * @param status Error Status
michael@0:      * @internal
michael@0:      */
michael@0:     UResourceBundle* getByKey2(const char *key, const char *subKey, UErrorCode& status);
michael@0: 
michael@0:     /**
michael@0:      * Load data for calendar. Note, this object owns the resources, do NOT call ures_close()!
michael@0:      * data is located in:   "calendar/key/contextKey/subKey"
michael@0:      * for example,  calendar/dayNames/standalone/narrow
michael@0:      * The ResourceBundle C++ API should NOT be used because it is too slow for a low level API.
michael@0:      *
michael@0:      * @param key Resource key to data
michael@0:      * @param contextKey Resource key to data
michael@0:      * @param subKey Resource key to data
michael@0:      * @param status Error Status
michael@0:      * @internal
michael@0:      */
michael@0:     UResourceBundle* getByKey3(const char *key, const char *contextKey, const char *subKey, UErrorCode& status);
michael@0: 
michael@0:     ~CalendarData();
michael@0: 
michael@0: private:
michael@0:     void initData(const char *locale, const char *type, UErrorCode& status);
michael@0: 
michael@0:     UResourceBundle *fFillin;
michael@0:     UResourceBundle *fOtherFillin;
michael@0:     UResourceBundle *fBundle;
michael@0:     UResourceBundle *fFallback;
michael@0:     CalendarData(); // Not implemented.
michael@0: };
michael@0: 
michael@0: U_NAMESPACE_END
michael@0: 
michael@0: #endif // !UCONFIG_NO_FORMATTING
michael@0: #endif // GREGOIMP_H
michael@0: 
michael@0: //eof