1 /*
2 **********************************************************************
3 * Copyright (c) 2003-2007, 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.
26 */
27 class Math {
28 public:
29 /**
30 * Divide two integers, returning the floor of the quotient.
31 * Unlike the built-in division, this is mathematically
32 * well-behaved. E.g., <code>-1/4</code> => 0 but
33 * <code>floorDivide(-1,4)</code> => -1.
34 * @param numerator the numerator
35 * @param denominator a divisor which must be != 0
36 * @return the floor of the quotient
37 */
38 static int32_t floorDivide(int32_t numerator, int32_t denominator);
39
40 /**
41 * Divide two numbers, returning the floor of the quotient.
42 * Unlike the built-in division, this is mathematically
43 * well-behaved. E.g., <code>-1/4</code> => 0 but
44 * <code>floorDivide(-1,4)</code> => -1.
45 * @param numerator the numerator
46 * @param denominator a divisor which must be != 0
47 * @return the floor of the quotient
48 */
49 static inline double floorDivide(double numerator, double denominator);
50
51 /**
52 * Divide two numbers, returning the floor of the quotient and
53 * the modulus remainder. Unlike the built-in division, this is
54 * mathematically well-behaved. E.g., <code>-1/4</code> => 0 and
55 * <code>-1%4</code> => -1, but <code>floorDivide(-1,4)</code> =>
56 * -1 with <code>remainder</code> => 3. NOTE: If numerator is
57 * too large, the returned quotient may overflow.
58 * @param numerator the numerator
59 * @param denominator a divisor which must be != 0
60 * @param remainder output parameter to receive the
61 * remainder. Unlike <code>numerator % denominator</code>, this
62 * will always be non-negative, in the half-open range <code>[0,
63 * |denominator|)</code>.
64 * @return the floor of the quotient
65 */
66 static int32_t floorDivide(double numerator, int32_t denominator,
67 int32_t& remainder);
68
69 /**
70 * For a positive divisor, return the quotient and remainder
71 * such that dividend = quotient*divisor + remainder and
72 * 0 <= remainder < divisor.
73 *
74 * Works around edge-case bugs. Handles pathological input
75 * (divident >> divisor) reasonably.
76 *
77 * Calling with a divisor <= 0 is disallowed.
78 */
79 static double floorDivide(double dividend, double divisor,
80 double& remainder);
81 };
82
83 // Useful millisecond constants
84 #define kOneDay (1.0 * U_MILLIS_PER_DAY) // 86,400,000
85 #define kOneHour (60*60*1000)
86 #define kOneMinute 60000
87 #define kOneSecond 1000
88 #define kOneMillisecond 1
89 #define kOneWeek (7.0 * kOneDay) // 604,800,000
90
91 // Epoch constants
92 #define kJan1_1JulianDay 1721426 // January 1, year 1 (Gregorian)
93
94 #define kEpochStartAsJulianDay 2440588 // January 1, 1970 (Gregorian)
95
96 #define kEpochYear 1970
97
98
99 #define kEarliestViableMillis -185331720384000000.0 // minimum representable by julian day -1e17
100
101 #define kLatestViableMillis 185753453990400000.0 // max representable by julian day +1e17
102
103 /**
104 * The minimum supported Julian day. This value is equivalent to
105 * MIN_MILLIS.
106 */
107 #define MIN_JULIAN (-0x7F000000)
108
109 /**
110 * The minimum supported epoch milliseconds. This value is equivalent
111 * to MIN_JULIAN.
112 */
113 #define MIN_MILLIS ((MIN_JULIAN - kEpochStartAsJulianDay) * kOneDay)
114
115 /**
116 * The maximum supported Julian day. This value is equivalent to
117 * MAX_MILLIS.
118 */
119 #define MAX_JULIAN (+0x7F000000)
120
121 /**
122 * The maximum supported epoch milliseconds. This value is equivalent
123 * to MAX_JULIAN.
124 */
125 #define MAX_MILLIS ((MAX_JULIAN - kEpochStartAsJulianDay) * kOneDay)
126
127 /**
128 * A utility class providing proleptic Gregorian calendar functions
129 * used by time zone and calendar code. Do not instantiate.
130 *
131 * Note: Unlike GregorianCalendar, all computations performed by this
132 * class occur in the pure proleptic GregorianCalendar.
133 */
134 class Grego {
135 public:
136 /**
137 * Return TRUE if the given year is a leap year.
138 * @param year Gregorian year, with 0 == 1 BCE, -1 == 2 BCE, etc.
139 * @return TRUE if the year is a leap year
140 */
141 static inline UBool isLeapYear(int32_t year);
142
143 /**
144 * Return the number of days in the given month.
145 * @param year Gregorian year, with 0 == 1 BCE, -1 == 2 BCE, etc.
146 * @param month 0-based month, with 0==Jan
147 * @return the number of days in the given month
148 */
149 static inline int8_t monthLength(int32_t year, int32_t month);
150
151 /**
152 * Return the length of a previous month of the Gregorian calendar.
153 * @param y the extended year
154 * @param m the 0-based month number
155 * @return the number of days in the month previous to the given month
156 */
157 static inline int8_t previousMonthLength(int y, int m);
158
159 /**
160 * Convert a year, month, and day-of-month, given in the proleptic
161 * Gregorian calendar, to 1970 epoch days.
162 * @param year Gregorian year, with 0 == 1 BCE, -1 == 2 BCE, etc.
163 * @param month 0-based month, with 0==Jan
164 * @param dom 1-based day of month
165 * @return the day number, with day 0 == Jan 1 1970
166 */
167 static double fieldsToDay(int32_t year, int32_t month, int32_t dom);
168
169 /**
170 * Convert a 1970-epoch day number to proleptic Gregorian year,
171 * month, day-of-month, and day-of-week.
172 * @param day 1970-epoch day (integral value)
173 * @param year output parameter to receive year
174 * @param month output parameter to receive month (0-based, 0==Jan)
175 * @param dom output parameter to receive day-of-month (1-based)
176 * @param dow output parameter to receive day-of-week (1-based, 1==Sun)
177 * @param doy output parameter to receive day-of-year (1-based)
178 */
179 static void dayToFields(double day, int32_t& year, int32_t& month,
180 int32_t& dom, int32_t& dow, int32_t& doy);
181
182 /**
183 * Convert a 1970-epoch day number to proleptic Gregorian year,
184 * month, day-of-month, and day-of-week.
185 * @param day 1970-epoch day (integral value)
186 * @param year output parameter to receive year
187 * @param month output parameter to receive month (0-based, 0==Jan)
188 * @param dom output parameter to receive day-of-month (1-based)
189 * @param dow output parameter to receive day-of-week (1-based, 1==Sun)
190 */
191 static inline void dayToFields(double day, int32_t& year, int32_t& month,
192 int32_t& dom, int32_t& dow);
193
194 /**
195 * Convert a 1970-epoch milliseconds to proleptic Gregorian year,
196 * month, day-of-month, and day-of-week, day of year and millis-in-day.
197 * @param time 1970-epoch milliseconds
198 * @param year output parameter to receive year
199 * @param month output parameter to receive month (0-based, 0==Jan)
200 * @param dom output parameter to receive day-of-month (1-based)
201 * @param dow output parameter to receive day-of-week (1-based, 1==Sun)
202 * @param doy output parameter to receive day-of-year (1-based)
203 * @param mid output parameter to recieve millis-in-day
204 */
205 static void timeToFields(UDate time, int32_t& year, int32_t& month,
206 int32_t& dom, int32_t& dow, int32_t& doy, int32_t& mid);
207
208 /**
209 * Return the day of week on the 1970-epoch day
210 * @param day the 1970-epoch day (integral value)
211 * @return the day of week
212 */
213 static int32_t dayOfWeek(double day);
214
215 /**
216 * Returns the ordinal number for the specified day of week within the month.
217 * The valid return value is 1, 2, 3, 4 or -1.
218 * @param year Gregorian year, with 0 == 1 BCE, -1 == 2 BCE, etc.
219 * @param month 0-based month, with 0==Jan
220 * @param dom 1-based day of month
221 * @return The ordinal number for the specified day of week within the month
222 */
223 static int32_t dayOfWeekInMonth(int32_t year, int32_t month, int32_t dom);
224
225 /**
226 * Converts Julian day to time as milliseconds.
227 * @param julian the given Julian day number.
228 * @return time as milliseconds.
229 * @internal
230 */
231 static inline double julianDayToMillis(int32_t julian);
232
233 /**
234 * Converts time as milliseconds to Julian day.
235 * @param millis the given milliseconds.
236 * @return the Julian day number.
237 * @internal
238 */
239 static inline int32_t millisToJulianDay(double millis);
240
241 /**
242 * Calculates the Gregorian day shift value for an extended year.
243 * @param eyear Extended year
244 * @returns number of days to ADD to Julian in order to convert from J->G
245 */
246 static inline int32_t gregorianShift(int32_t eyear);
247
248 private:
249 static const int16_t DAYS_BEFORE[24];
250 static const int8_t MONTH_LENGTH[24];
251 };
252
floorDivide(double numerator,double denominator)253 inline double Math::floorDivide(double numerator, double denominator) {
254 return uprv_floor(numerator / denominator);
255 }
256
isLeapYear(int32_t year)257 inline UBool Grego::isLeapYear(int32_t year) {
258 // year&0x3 == year%4
259 return ((year&0x3) == 0) && ((year%100 != 0) || (year%400 == 0));
260 }
261
262 inline int8_t
monthLength(int32_t year,int32_t month)263 Grego::monthLength(int32_t year, int32_t month) {
264 return MONTH_LENGTH[month + (isLeapYear(year) ? 12 : 0)];
265 }
266
267 inline int8_t
previousMonthLength(int y,int m)268 Grego::previousMonthLength(int y, int m) {
269 return (m > 0) ? monthLength(y, m-1) : 31;
270 }
271
dayToFields(double day,int32_t & year,int32_t & month,int32_t & dom,int32_t & dow)272 inline void Grego::dayToFields(double day, int32_t& year, int32_t& month,
273 int32_t& dom, int32_t& dow) {
274 int32_t doy_unused;
275 dayToFields(day,year,month,dom,dow,doy_unused);
276 }
277
julianDayToMillis(int32_t julian)278 inline double Grego::julianDayToMillis(int32_t julian)
279 {
280 return (julian - kEpochStartAsJulianDay) * kOneDay;
281 }
282
millisToJulianDay(double millis)283 inline int32_t Grego::millisToJulianDay(double millis) {
284 return (int32_t) (kEpochStartAsJulianDay + Math::floorDivide(millis, (double)kOneDay));
285 }
286
gregorianShift(int32_t eyear)287 inline int32_t Grego::gregorianShift(int32_t eyear) {
288 int32_t y = eyear-1;
289 int32_t gregShift = Math::floorDivide(y, 400) - Math::floorDivide(y, 100) + 2;
290 return gregShift;
291 }
292
293 /**
294 * This utility class provides convenient access to the data needed for a calendar.
295 * @internal ICU 3.0
296 */
297 class CalendarData : public UMemory {
298 public:
299 /**
300 * Construct a CalendarData from the given locale.
301 * @param loc locale to use. The 'calendar' keyword will be ignored.
302 * @param type calendar type. NULL indicates the gregorian calendar.
303 * No default lookup is done.
304 * @param status error code
305 */
306 CalendarData(const Locale& loc, const char *type, UErrorCode& status);
307
308 /**
309 * Load data for calendar. Note, this object owns the resources, do NOT call ures_close()!
310 * The ResourceBundle C++ API should NOT be used because it is too slow for a low level API.
311 *
312 * @param key Resource key to data
313 * @param status Error Status
314 * @internal
315 */
316 UResourceBundle* getByKey(const char *key, UErrorCode& status);
317
318 /**
319 * Load data for calendar. Note, this object owns the resources, do NOT call ures_close()!
320 * There is an implicit key of 'format'
321 * data is located in: "calendar/key/format/subKey"
322 * for example, calendar/dayNames/format/abbreviated
323 * The ResourceBundle C++ API should NOT be used because it is too slow for a low level API.
324 *
325 * @param key Resource key to data
326 * @param subKey Resource key to data
327 * @param status Error Status
328 * @internal
329 */
330 UResourceBundle* getByKey2(const char *key, const char *subKey, UErrorCode& status);
331
332 /**
333 * Load data for calendar. Note, this object owns the resources, do NOT call ures_close()!
334 * data is located in: "calendar/key/contextKey/subKey"
335 * for example, calendar/dayNames/standalone/narrow
336 * The ResourceBundle C++ API should NOT be used because it is too slow for a low level API.
337 *
338 * @param key Resource key to data
339 * @param contextKey Resource key to data
340 * @param subKey Resource key to data
341 * @param status Error Status
342 * @internal
343 */
344 UResourceBundle* getByKey3(const char *key, const char *contextKey, const char *subKey, UErrorCode& status);
345
346 ~CalendarData();
347
348 private:
349 void initData(const char *locale, const char *type, UErrorCode& status);
350
351 UResourceBundle *fFillin;
352 UResourceBundle *fOtherFillin;
353 UResourceBundle *fBundle;
354 UResourceBundle *fFallback;
355 CalendarData(); // Not implemented.
356 };
357
358 U_NAMESPACE_END
359
360 #endif // !UCONFIG_NO_FORMATTING
361 #endif // GREGOIMP_H
362
363 //eof
364