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1 /*
2  **********************************************************************
3  * Copyright (c) 2003-2008, International Business Machines
4  * Corporation and others.  All Rights Reserved.
5  **********************************************************************
6  * Author: Alan Liu
7  * Created: September 2 2003
8  * Since: ICU 2.8
9  **********************************************************************
10  */
11 
12 #ifndef GREGOIMP_H
13 #define GREGOIMP_H
14 #include "unicode/utypes.h"
15 #if !UCONFIG_NO_FORMATTING
16 
17 #include "unicode/ures.h"
18 #include "unicode/locid.h"
19 #include "putilimp.h"
20 
21 U_NAMESPACE_BEGIN
22 
23 /**
24  * A utility class providing mathematical functions used by time zone
25  * and calendar code.  Do not instantiate.  Formerly just named 'Math'.
26  * @internal
27  */
28 class ClockMath {
29  public:
30     /**
31      * Divide two integers, returning the floor of the quotient.
32      * Unlike the built-in division, this is mathematically
33      * well-behaved.  E.g., <code>-1/4</code> => 0 but
34      * <code>floorDivide(-1,4)</code> => -1.
35      * @param numerator the numerator
36      * @param denominator a divisor which must be != 0
37      * @return the floor of the quotient
38      */
39     static int32_t floorDivide(int32_t numerator, int32_t denominator);
40 
41     /**
42      * Divide two numbers, returning the floor of the quotient.
43      * Unlike the built-in division, this is mathematically
44      * well-behaved.  E.g., <code>-1/4</code> => 0 but
45      * <code>floorDivide(-1,4)</code> => -1.
46      * @param numerator the numerator
47      * @param denominator a divisor which must be != 0
48      * @return the floor of the quotient
49      */
50     static inline double floorDivide(double numerator, double denominator);
51 
52     /**
53      * Divide two numbers, returning the floor of the quotient and
54      * the modulus remainder.  Unlike the built-in division, this is
55      * mathematically well-behaved.  E.g., <code>-1/4</code> => 0 and
56      * <code>-1%4</code> => -1, but <code>floorDivide(-1,4)</code> =>
57      * -1 with <code>remainder</code> => 3.  NOTE: If numerator is
58      * too large, the returned quotient may overflow.
59      * @param numerator the numerator
60      * @param denominator a divisor which must be != 0
61      * @param remainder output parameter to receive the
62      * remainder. Unlike <code>numerator % denominator</code>, this
63      * will always be non-negative, in the half-open range <code>[0,
64      * |denominator|)</code>.
65      * @return the floor of the quotient
66      */
67     static int32_t floorDivide(double numerator, int32_t denominator,
68                                int32_t& remainder);
69 
70     /**
71      * For a positive divisor, return the quotient and remainder
72      * such that dividend = quotient*divisor + remainder and
73      * 0 <= remainder < divisor.
74      *
75      * Works around edge-case bugs.  Handles pathological input
76      * (divident >> divisor) reasonably.
77      *
78      * Calling with a divisor <= 0 is disallowed.
79      */
80     static double floorDivide(double dividend, double divisor,
81                               double& remainder);
82 };
83 
84 // Useful millisecond constants
85 #define kOneDay    (1.0 * U_MILLIS_PER_DAY)       //  86,400,000
86 #define kOneHour   (60*60*1000)
87 #define kOneMinute 60000
88 #define kOneSecond 1000
89 #define kOneMillisecond  1
90 #define kOneWeek   (7.0 * kOneDay) // 604,800,000
91 
92 // Epoch constants
93 #define kJan1_1JulianDay  1721426 // January 1, year 1 (Gregorian)
94 
95 #define kEpochStartAsJulianDay  2440588 // January 1, 1970 (Gregorian)
96 
97 #define kEpochYear              1970
98 
99 
100 #define kEarliestViableMillis  -185331720384000000.0  // minimum representable by julian day  -1e17
101 
102 #define kLatestViableMillis     185753453990400000.0  // max representable by julian day      +1e17
103 
104 /**
105  * The minimum supported Julian day.  This value is equivalent to
106  * MIN_MILLIS.
107  */
108 #define MIN_JULIAN (-0x7F000000)
109 
110 /**
111  * The minimum supported epoch milliseconds.  This value is equivalent
112  * to MIN_JULIAN.
113  */
114 #define MIN_MILLIS ((MIN_JULIAN - kEpochStartAsJulianDay) * kOneDay)
115 
116 /**
117  * The maximum supported Julian day.  This value is equivalent to
118  * MAX_MILLIS.
119  */
120 #define MAX_JULIAN (+0x7F000000)
121 
122 /**
123  * The maximum supported epoch milliseconds.  This value is equivalent
124  * to MAX_JULIAN.
125  */
126 #define MAX_MILLIS ((MAX_JULIAN - kEpochStartAsJulianDay) * kOneDay)
127 
128 /**
129  * A utility class providing proleptic Gregorian calendar functions
130  * used by time zone and calendar code.  Do not instantiate.
131  *
132  * Note:  Unlike GregorianCalendar, all computations performed by this
133  * class occur in the pure proleptic GregorianCalendar.
134  */
135 class Grego {
136  public:
137     /**
138      * Return TRUE if the given year is a leap year.
139      * @param year Gregorian year, with 0 == 1 BCE, -1 == 2 BCE, etc.
140      * @return TRUE if the year is a leap year
141      */
142     static inline UBool isLeapYear(int32_t year);
143 
144     /**
145      * Return the number of days in the given month.
146      * @param year Gregorian year, with 0 == 1 BCE, -1 == 2 BCE, etc.
147      * @param month 0-based month, with 0==Jan
148      * @return the number of days in the given month
149      */
150     static inline int8_t monthLength(int32_t year, int32_t month);
151 
152     /**
153      * Return the length of a previous month of the Gregorian calendar.
154      * @param y the extended year
155      * @param m the 0-based month number
156      * @return the number of days in the month previous to the given month
157      */
158     static inline int8_t previousMonthLength(int y, int m);
159 
160     /**
161      * Convert a year, month, and day-of-month, given in the proleptic
162      * Gregorian calendar, to 1970 epoch days.
163      * @param year Gregorian year, with 0 == 1 BCE, -1 == 2 BCE, etc.
164      * @param month 0-based month, with 0==Jan
165      * @param dom 1-based day of month
166      * @return the day number, with day 0 == Jan 1 1970
167      */
168     static double fieldsToDay(int32_t year, int32_t month, int32_t dom);
169 
170     /**
171      * Convert a 1970-epoch day number to proleptic Gregorian year,
172      * month, day-of-month, and day-of-week.
173      * @param day 1970-epoch day (integral value)
174      * @param year output parameter to receive year
175      * @param month output parameter to receive month (0-based, 0==Jan)
176      * @param dom output parameter to receive day-of-month (1-based)
177      * @param dow output parameter to receive day-of-week (1-based, 1==Sun)
178      * @param doy output parameter to receive day-of-year (1-based)
179      */
180     static void dayToFields(double day, int32_t& year, int32_t& month,
181                             int32_t& dom, int32_t& dow, int32_t& doy);
182 
183     /**
184      * Convert a 1970-epoch day number to proleptic Gregorian year,
185      * month, day-of-month, and day-of-week.
186      * @param day 1970-epoch day (integral value)
187      * @param year output parameter to receive year
188      * @param month output parameter to receive month (0-based, 0==Jan)
189      * @param dom output parameter to receive day-of-month (1-based)
190      * @param dow output parameter to receive day-of-week (1-based, 1==Sun)
191      */
192     static inline void dayToFields(double day, int32_t& year, int32_t& month,
193                                    int32_t& dom, int32_t& dow);
194 
195     /**
196      * Convert a 1970-epoch milliseconds to proleptic Gregorian year,
197      * month, day-of-month, and day-of-week, day of year and millis-in-day.
198      * @param time 1970-epoch milliseconds
199      * @param year output parameter to receive year
200      * @param month output parameter to receive month (0-based, 0==Jan)
201      * @param dom output parameter to receive day-of-month (1-based)
202      * @param dow output parameter to receive day-of-week (1-based, 1==Sun)
203      * @param doy output parameter to receive day-of-year (1-based)
204      * @param mid output parameter to recieve millis-in-day
205      */
206     static void timeToFields(UDate time, int32_t& year, int32_t& month,
207                             int32_t& dom, int32_t& dow, int32_t& doy, int32_t& mid);
208 
209     /**
210      * Return the day of week on the 1970-epoch day
211      * @param day the 1970-epoch day (integral value)
212      * @return the day of week
213      */
214     static int32_t dayOfWeek(double day);
215 
216     /**
217      * Returns the ordinal number for the specified day of week within the month.
218      * The valid return value is 1, 2, 3, 4 or -1.
219      * @param year Gregorian year, with 0 == 1 BCE, -1 == 2 BCE, etc.
220      * @param month 0-based month, with 0==Jan
221      * @param dom 1-based day of month
222      * @return The ordinal number for the specified day of week within the month
223      */
224     static int32_t dayOfWeekInMonth(int32_t year, int32_t month, int32_t dom);
225 
226     /**
227      * Converts Julian day to time as milliseconds.
228      * @param julian the given Julian day number.
229      * @return time as milliseconds.
230      * @internal
231      */
232     static inline double julianDayToMillis(int32_t julian);
233 
234     /**
235      * Converts time as milliseconds to Julian day.
236      * @param millis the given milliseconds.
237      * @return the Julian day number.
238      * @internal
239      */
240     static inline int32_t millisToJulianDay(double millis);
241 
242     /**
243      * Calculates the Gregorian day shift value for an extended year.
244      * @param eyear Extended year
245      * @returns number of days to ADD to Julian in order to convert from J->G
246      */
247     static inline int32_t gregorianShift(int32_t eyear);
248 
249  private:
250     static const int16_t DAYS_BEFORE[24];
251     static const int8_t MONTH_LENGTH[24];
252 };
253 
floorDivide(double numerator,double denominator)254 inline double ClockMath::floorDivide(double numerator, double denominator) {
255     return uprv_floor(numerator / denominator);
256 }
257 
isLeapYear(int32_t year)258 inline UBool Grego::isLeapYear(int32_t year) {
259     // year&0x3 == year%4
260     return ((year&0x3) == 0) && ((year%100 != 0) || (year%400 == 0));
261 }
262 
263 inline int8_t
monthLength(int32_t year,int32_t month)264 Grego::monthLength(int32_t year, int32_t month) {
265     return MONTH_LENGTH[month + (isLeapYear(year) ? 12 : 0)];
266 }
267 
268 inline int8_t
previousMonthLength(int y,int m)269 Grego::previousMonthLength(int y, int m) {
270   return (m > 0) ? monthLength(y, m-1) : 31;
271 }
272 
dayToFields(double day,int32_t & year,int32_t & month,int32_t & dom,int32_t & dow)273 inline void Grego::dayToFields(double day, int32_t& year, int32_t& month,
274                                int32_t& dom, int32_t& dow) {
275   int32_t doy_unused;
276   dayToFields(day,year,month,dom,dow,doy_unused);
277 }
278 
julianDayToMillis(int32_t julian)279 inline double Grego::julianDayToMillis(int32_t julian)
280 {
281   return (julian - kEpochStartAsJulianDay) * kOneDay;
282 }
283 
millisToJulianDay(double millis)284 inline int32_t Grego::millisToJulianDay(double millis) {
285   return (int32_t) (kEpochStartAsJulianDay + ClockMath::floorDivide(millis, (double)kOneDay));
286 }
287 
gregorianShift(int32_t eyear)288 inline int32_t Grego::gregorianShift(int32_t eyear) {
289   int32_t y = eyear-1;
290   int32_t gregShift = ClockMath::floorDivide(y, 400) - ClockMath::floorDivide(y, 100) + 2;
291   return gregShift;
292 }
293 
294 /**
295  * This utility class provides convenient access to the data needed for a calendar.
296  * @internal ICU 3.0
297  */
298 class CalendarData : public UMemory {
299 public:
300     /**
301      * Construct a CalendarData from the given locale.
302      * @param loc locale to use. The 'calendar' keyword will be ignored.
303      * @param type calendar type. NULL indicates the gregorian calendar.
304      * No default lookup is done.
305      * @param status error code
306      */
307     CalendarData(const Locale& loc, const char *type, UErrorCode& status);
308 
309     /**
310      * Load data for calendar. Note, this object owns the resources, do NOT call ures_close()!
311      * The ResourceBundle C++ API should NOT be used because it is too slow for a low level API.
312      *
313      * @param key Resource key to data
314      * @param status Error Status
315      * @internal
316      */
317     UResourceBundle* getByKey(const char *key, UErrorCode& status);
318 
319     /**
320      * Load data for calendar. Note, this object owns the resources, do NOT call ures_close()!
321      * There is an implicit key of 'format'
322      * data is located in:   "calendar/key/format/subKey"
323      * for example,  calendar/dayNames/format/abbreviated
324      * The ResourceBundle C++ API should NOT be used because it is too slow for a low level API.
325      *
326      * @param key Resource key to data
327      * @param subKey Resource key to data
328      * @param status Error Status
329      * @internal
330      */
331     UResourceBundle* getByKey2(const char *key, const char *subKey, UErrorCode& status);
332 
333     /**
334      * Load data for calendar. Note, this object owns the resources, do NOT call ures_close()!
335      * data is located in:   "calendar/key/contextKey/subKey"
336      * for example,  calendar/dayNames/standalone/narrow
337      * The ResourceBundle C++ API should NOT be used because it is too slow for a low level API.
338      *
339      * @param key Resource key to data
340      * @param contextKey Resource key to data
341      * @param subKey Resource key to data
342      * @param status Error Status
343      * @internal
344      */
345     UResourceBundle* getByKey3(const char *key, const char *contextKey, const char *subKey, UErrorCode& status);
346 
347     ~CalendarData();
348 
349 private:
350     void initData(const char *locale, const char *type, UErrorCode& status);
351 
352     UResourceBundle *fFillin;
353     UResourceBundle *fOtherFillin;
354     UResourceBundle *fBundle;
355     UResourceBundle *fFallback;
356     CalendarData(); // Not implemented.
357 };
358 
359 U_NAMESPACE_END
360 
361 #endif // !UCONFIG_NO_FORMATTING
362 #endif // GREGOIMP_H
363 
364 //eof
365