1/*
2******************************************************************************
3* Copyright (C) 2003-2013, International Business Machines Corporation
4* and others. All Rights Reserved.
5******************************************************************************
6*
7* File ISLAMCAL.H
8*
9* Modification History:
10*
11*   Date        Name        Description
12*   10/14/2003  srl         ported from java IslamicCalendar
13*****************************************************************************
14*/
15
16#include "islamcal.h"
17
18#if !UCONFIG_NO_FORMATTING
19
20#include "umutex.h"
21#include <float.h>
22#include "gregoimp.h" // Math
23#include "astro.h" // CalendarAstronomer
24#include "uhash.h"
25#include "ucln_in.h"
26#include "uassert.h"
27
28static const UDate HIJRA_MILLIS = -42521587200000.0;    // 7/16/622 AD 00:00
29
30// Debugging
31#ifdef U_DEBUG_ISLAMCAL
32# include <stdio.h>
33# include <stdarg.h>
34static void debug_islamcal_loc(const char *f, int32_t l)
35{
36    fprintf(stderr, "%s:%d: ", f, l);
37}
38
39static void debug_islamcal_msg(const char *pat, ...)
40{
41    va_list ap;
42    va_start(ap, pat);
43    vfprintf(stderr, pat, ap);
44    fflush(stderr);
45}
46// must use double parens, i.e.:  U_DEBUG_ISLAMCAL_MSG(("four is: %d",4));
47#define U_DEBUG_ISLAMCAL_MSG(x) {debug_islamcal_loc(__FILE__,__LINE__);debug_islamcal_msg x;}
48#else
49#define U_DEBUG_ISLAMCAL_MSG(x)
50#endif
51
52
53// --- The cache --
54// cache of months
55static UMutex astroLock = U_MUTEX_INITIALIZER;  // pod bay door lock
56static icu::CalendarCache *gMonthCache = NULL;
57static icu::CalendarAstronomer *gIslamicCalendarAstro = NULL;
58
59U_CDECL_BEGIN
60static UBool calendar_islamic_cleanup(void) {
61    if (gMonthCache) {
62        delete gMonthCache;
63        gMonthCache = NULL;
64    }
65    if (gIslamicCalendarAstro) {
66        delete gIslamicCalendarAstro;
67        gIslamicCalendarAstro = NULL;
68    }
69    return TRUE;
70}
71U_CDECL_END
72
73U_NAMESPACE_BEGIN
74
75// Implementation of the IslamicCalendar class
76
77/**
78 * Friday EPOC
79 */
80static const int32_t CIVIL_EPOC = 1948440;
81
82/**
83  * Thursday EPOC
84  */
85static const int32_t ASTRONOMICAL_EPOC = 1948439;
86
87
88static const int32_t UMALQURA_YEAR_START = 1318;
89static const int32_t UMALQURA_YEAR_END = 1480;
90
91static const int UMALQURA_MONTHLENGTH[] = {
92    //* 1318 -1322 */ "0101 0111 0100", "1001 0111 0110", "0100 1011 0111", "0010 0101 0111", "0101 0010 1011",
93                            0x0574,           0x0975,           0x06A7,           0x0257,           0x052B,
94    //* 1323 -1327 */ "0110 1001 0101", "0110 1100 1010", "1010 1101 0101", "0101 0101 1011", "0010 0101 1101",
95                            0x0695,           0x06CA,           0x0AD5,           0x055B,           0x025B,
96    //* 1328 -1332 */ "1001 0010 1101", "1100 1001 0101", "1101 0100 1010", "1110 1010 0101", "0110 1101 0010",
97                            0x092D,           0x0C95,           0x0D4A,           0x0E5B,           0x025B,
98    //* 1333 -1337 */ "1010 1101 0101", "0101 0101 1010", "1010 1010 1011", "0100 0100 1011", "0110 1010 0101",
99                            0x0AD5,           0x055A,           0x0AAB,           0x044B,           0x06A5,
100    //* 1338 -1342 */ "0111 0101 0010", "1011 1010 1001", "0011 0111 0100", "1010 1011 0110", "0101 0101 0110",
101                            0x0752,           0x0BA9,           0x0374,           0x0AB6,           0x0556,
102    //* 1343 -1347 */ "1010 1010 1010", "1101 0101 0010", "1101 1010 1001", "0101 1101 0100", "1010 1110 1010",
103                            0x0AAA,           0x0D52,           0x0DA9,           0x05D4,           0x0AEA,
104    //* 1348 -1352 */ "0100 1101 1101", "0010 0110 1110", "1001 0010 1110", "1010 1010 0110", "1101 0101 0100",
105                            0x04DD,           0x026E,           0x092E,           0x0AA6,           0x0D54,
106    //* 1353 -1357 */ "0101 1010 1010", "0101 1011 0101", "0010 1011 0100", "1001 0011 0111", "0100 1001 1011",
107                            0x05AA,           0x05B5,           0x02B4,           0x0937,           0x049B,
108    //* 1358 -1362 */ "1010 0100 1011", "1011 0010 0101", "1011 0101 0100", "1011 0110 1010", "0101 0110 1101",
109                            0x0A4B,           0x0B25,           0x0B54,           0x0B6A,           0x056D,
110    //* 1363 -1367 */ "0100 1010 1101", "1010 0101 0101", "1101 0010 0101", "1110 1001 0010", "1110 1100 1001",
111                            0x04AD,           0x0A55,           0x0D25,           0x0E92,           0x0EC9,
112    //* 1368 -1372 */ "0110 1101 0100", "1010 1110 1010", "0101 0110 1011", "0100 1010 1011", "0110 1000 0101",
113                            0x06D4,           0x0ADA,           0x056B,           0x04AB,           0x0685,
114    //* 1373 -1377 */ "1011 0100 1001", "1011 1010 0100", "1011 1011 0010", "0101 1011 0101", "0010 1011 1010",
115                            0x0B49,           0x0BA4,           0x0BB2,           0x05B5,           0x02BA,
116    //* 1378 -1382 */ "1001 0101 1011", "0100 1010 1011", "0101 0101 0101", "0110 1011 0010", "0110 1101 1001",
117                            0x095B,           0x04AB,           0x0555,           0x06B2,           0x06D9,
118    //* 1383 -1387 */ "0010 1110 1100", "1001 0110 1110", "0100 1010 1110", "1010 0101 0110", "1101 0010 1010",
119                            0x02EC,           0x096E,           0x04AE,           0x0A56,           0x0D2A,
120    //* 1388 -1392 */ "1101 0101 0101", "0101 1010 1010", "1010 1011 0101", "0100 1011 1011", "0000 0101 1011",
121                            0x0D55,           0x05AA,           0x0AB5,           0x04BB,           0x005B,
122    //* 1393 -1397 */ "1001 0010 1011", "1010 1001 0101", "0011 0100 1010", "1011 1010 0101", "0101 1010 1010",
123                            0x092B,           0x0A95,           0x034A,           0x0BA5,           0x05AA,
124    //* 1398 -1402 */ "1010 1011 0101", "0101 0101 0110", "1010 1001 0110", "1101 0100 1010", "1110 1010 0101",
125                            0x0AB5,           0x0556,           0x0A96,           0x0B4A,           0x0EA5,
126    //* 1403 -1407 */ "0111 0101 0010", "0110 1110 1001", "0011 0110 1010", "1010 1010 1101", "0101 0101 0101",
127                            0x0752,           0x06E9,           0x036A,           0x0AAD,           0x0555,
128    //* 1408 -1412 */ "1010 1010 0101", "1011 0101 0010", "1011 1010 1001", "0101 1011 0100", "1001 1011 1010",
129                            0x0AA5,           0x0B52,           0x0BA9,           0x05B4,           0x09BA,
130    //* 1413 -1417 */ "0100 1101 1011", "0010 0101 1101", "0101 0010 1101", "1010 1010 0101", "1010 1101 0100",
131                            0x04DB,           0x025D,           0x052D,           0x0AA5,           0x0AD4,
132    //* 1418 -1422 */ "1010 1110 1010", "0101 0110 1101", "0100 1011 1101", "0010 0011 1101", "1001 0001 1101",
133                            0x0AEA,           0x056D,           0x04BD,           0x023D,           0x091D,
134    //* 1423 -1427 */ "1010 1001 0101", "1011 0100 1010", "1011 0101 1010", "0101 0110 1101", "0010 1011 0110",
135                            0x0A95,           0x0B4A,           0x0B5A,           0x056D,           0x02B6,
136    //* 1428 -1432 */ "1001 0011 1011", "0100 1001 1011", "0110 0101 0101", "0110 1010 1001", "0111 0101 0100",
137                            0x093B,           0x049B,           0x0655,           0x06A9,           0x0754,
138    //* 1433 -1437 */ "1011 0110 1010", "0101 0110 1100", "1010 1010 1101", "0101 0101 0101", "1011 0010 1001",
139                            0x0B6A,           0x056C,           0x0AAD,           0x0555,           0x0B29,
140    //* 1438 -1442 */ "1011 1001 0010", "1011 1010 1001", "0101 1101 0100", "1010 1101 1010", "0101 0101 1010",
141                            0x0B92,           0x0BA9,           0x05D4,           0x0ADA,           0x055A,
142    //* 1443 -1447 */ "1010 1010 1011", "0101 1001 0101", "0111 0100 1001", "0111 0110 0100", "1011 1010 1010",
143                            0x0AAB,           0x0595,           0x0749,           0x0764,           0x0BAA,
144    //* 1448 -1452 */ "0101 1011 0101", "0010 1011 0110", "1010 0101 0110", "1110 0100 1101", "1011 0010 0101",
145                            0x05B5,           0x02B6,           0x0A56,           0x0E4D,           0x0B25,
146    //* 1453 -1457 */ "1011 0101 0010", "1011 0110 1010", "0101 1010 1101", "0010 1010 1110", "1001 0010 1111",
147                            0x0B52,           0x0B6A,           0x05AD,           0x02AE,           0x092F,
148    //* 1458 -1462 */ "0100 1001 0111", "0110 0100 1011", "0110 1010 0101", "0110 1010 1100", "1010 1101 0110",
149                            0x0497,           0x064B,           0x06A5,           0x06AC,           0x0AD6,
150    //* 1463 -1467 */ "0101 0101 1101", "0100 1001 1101", "1010 0100 1101", "1101 0001 0110", "1101 1001 0101",
151                            0x055D,           0x049D,           0x0A4D,           0x0D16,           0x0D95,
152    //* 1468 -1472 */ "0101 1010 1010", "0101 1011 0101", "0010 1001 1010", "1001 0101 1011", "0100 1010 1100",
153                            0x05AA,           0x05B5,           0x029A,           0x095B,           0x04AC,
154    //* 1473 -1477 */ "0101 1001 0101", "0110 1100 1010", "0110 1110 0100", "1010 1110 1010", "0100 1111 0101",
155                            0x0595,           0x06CA,           0x06E4,           0x0AEA,           0x04F5,
156    //* 1478 -1480 */ "0010 1011 0110", "1001 0101 0110", "1010 1010 1010"
157                            0x02B6,           0x0956,           0x0AAA
158};
159
160int32_t getUmalqura_MonthLength(int32_t y, int32_t m) {
161    int32_t mask = (int32_t) (0x01 << (11 - m));    // set mask for bit corresponding to month
162    if((UMALQURA_MONTHLENGTH[y] & mask) == 0 )
163        return 29;
164    else
165        return 30;
166
167}
168
169//-------------------------------------------------------------------------
170// Constructors...
171//-------------------------------------------------------------------------
172
173const char *IslamicCalendar::getType() const {
174    const char *sType = NULL;
175
176    switch (cType) {
177    case CIVIL:
178        sType = "islamic-civil";
179        break;
180    case ASTRONOMICAL:
181        sType = "islamic";
182        break;
183    case TBLA:
184        sType = "islamic-tbla";
185        break;
186    case UMALQURA:
187        sType = "islamic-umalqura";
188        break;
189    default:
190        U_ASSERT(false); // out of range
191        sType = "islamic";  // "islamic" is used as the generic type
192        break;
193    }
194    return sType;
195}
196
197Calendar* IslamicCalendar::clone() const {
198    return new IslamicCalendar(*this);
199}
200
201IslamicCalendar::IslamicCalendar(const Locale& aLocale, UErrorCode& success, ECalculationType type)
202:   Calendar(TimeZone::createDefault(), aLocale, success),
203cType(type)
204{
205    setTimeInMillis(getNow(), success); // Call this again now that the vtable is set up properly.
206}
207
208IslamicCalendar::IslamicCalendar(const IslamicCalendar& other) : Calendar(other), cType(other.cType) {
209}
210
211IslamicCalendar::~IslamicCalendar()
212{
213}
214
215void IslamicCalendar::setCalculationType(ECalculationType type, UErrorCode &status)
216{
217    if (cType != type) {
218        // The fields of the calendar will become invalid, because the calendar
219        // rules are different
220        UDate m = getTimeInMillis(status);
221        cType = type;
222        clear();
223        setTimeInMillis(m, status);
224    }
225}
226
227/**
228* Returns <code>true</code> if this object is using the fixed-cycle civil
229* calendar, or <code>false</code> if using the religious, astronomical
230* calendar.
231* @draft ICU 2.4
232*/
233UBool IslamicCalendar::isCivil() {
234    return (cType == CIVIL);
235}
236
237//-------------------------------------------------------------------------
238// Minimum / Maximum access functions
239//-------------------------------------------------------------------------
240
241// Note: Current IslamicCalendar implementation does not work
242// well with negative years.
243
244// TODO: In some cases the current ICU Islamic calendar implementation shows
245// a month as having 31 days. Since date parsing now uses range checks based
246// on the table below, we need to change the range for last day of month to
247// include 31 as a workaround until the implementation is fixed.
248static const int32_t LIMITS[UCAL_FIELD_COUNT][4] = {
249    // Minimum  Greatest    Least  Maximum
250    //           Minimum  Maximum
251    {        0,        0,        0,        0}, // ERA
252    {        1,        1,  5000000,  5000000}, // YEAR
253    {        0,        0,       11,       11}, // MONTH
254    {        1,        1,       50,       51}, // WEEK_OF_YEAR
255    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // WEEK_OF_MONTH
256    {        1,        1,       29,       31}, // DAY_OF_MONTH - 31 to workaround for cal implementation bug, should be 30
257    {        1,        1,      354,      355}, // DAY_OF_YEAR
258    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // DAY_OF_WEEK
259    {       -1,       -1,        5,        5}, // DAY_OF_WEEK_IN_MONTH
260    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // AM_PM
261    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // HOUR
262    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // HOUR_OF_DAY
263    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // MINUTE
264    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // SECOND
265    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // MILLISECOND
266    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // ZONE_OFFSET
267    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // DST_OFFSET
268    {        1,        1,  5000000,  5000000}, // YEAR_WOY
269    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // DOW_LOCAL
270    {        1,        1,  5000000,  5000000}, // EXTENDED_YEAR
271    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // JULIAN_DAY
272    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // MILLISECONDS_IN_DAY
273    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // IS_LEAP_MONTH
274};
275
276/**
277* @draft ICU 2.4
278*/
279int32_t IslamicCalendar::handleGetLimit(UCalendarDateFields field, ELimitType limitType) const {
280    return LIMITS[field][limitType];
281}
282
283//-------------------------------------------------------------------------
284// Assorted calculation utilities
285//
286
287/**
288* Determine whether a year is a leap year in the Islamic civil calendar
289*/
290UBool IslamicCalendar::civilLeapYear(int32_t year)
291{
292    return (14 + 11 * year) % 30 < 11;
293}
294
295/**
296* Return the day # on which the given year starts.  Days are counted
297* from the Hijri epoch, origin 0.
298*/
299int32_t IslamicCalendar::yearStart(int32_t year) const{
300    if (cType == CIVIL || cType == TBLA ||
301        (cType == UMALQURA && year < UMALQURA_YEAR_START))
302    {
303        return (year-1)*354 + ClockMath::floorDivide((3+11*year),30);
304    } else if(cType==ASTRONOMICAL){
305        return trueMonthStart(12*(year-1));
306    } else {
307        int32_t ys = yearStart(UMALQURA_YEAR_START-1);
308        ys+= handleGetYearLength(UMALQURA_YEAR_START-1);
309        for(int i=UMALQURA_YEAR_START; i< year; i++){
310            ys+= handleGetYearLength(i);
311        }
312        return ys;
313    }
314}
315
316/**
317* Return the day # on which the given month starts.  Days are counted
318* from the Hijri epoch, origin 0.
319*
320* @param year  The hijri year
321* @param year  The hijri month, 0-based
322*/
323int32_t IslamicCalendar::monthStart(int32_t year, int32_t month) const {
324    if (cType == CIVIL || cType == TBLA) {
325        return (int32_t)uprv_ceil(29.5*month)
326            + (year-1)*354 + (int32_t)ClockMath::floorDivide((3+11*year),30);
327    } else if(cType==ASTRONOMICAL){
328        return trueMonthStart(12*(year-1) + month);
329    } else {
330        int32_t ms = yearStart(year);
331        for(int i=0; i< month; i++){
332            ms+= handleGetMonthLength(year, i);
333        }
334        return ms;
335    }
336}
337
338/**
339* Find the day number on which a particular month of the true/lunar
340* Islamic calendar starts.
341*
342* @param month The month in question, origin 0 from the Hijri epoch
343*
344* @return The day number on which the given month starts.
345*/
346int32_t IslamicCalendar::trueMonthStart(int32_t month) const
347{
348    UErrorCode status = U_ZERO_ERROR;
349    int32_t start = CalendarCache::get(&gMonthCache, month, status);
350
351    if (start==0) {
352        // Make a guess at when the month started, using the average length
353        UDate origin = HIJRA_MILLIS
354            + uprv_floor(month * CalendarAstronomer::SYNODIC_MONTH) * kOneDay;
355
356        // moonAge will fail due to memory allocation error
357        double age = moonAge(origin, status);
358        if (U_FAILURE(status)) {
359            goto trueMonthStartEnd;
360        }
361
362        if (age >= 0) {
363            // The month has already started
364            do {
365                origin -= kOneDay;
366                age = moonAge(origin, status);
367                if (U_FAILURE(status)) {
368                    goto trueMonthStartEnd;
369                }
370            } while (age >= 0);
371        }
372        else {
373            // Preceding month has not ended yet.
374            do {
375                origin += kOneDay;
376                age = moonAge(origin, status);
377                if (U_FAILURE(status)) {
378                    goto trueMonthStartEnd;
379                }
380            } while (age < 0);
381        }
382        start = (int32_t)ClockMath::floorDivide((origin - HIJRA_MILLIS), (double)kOneDay) + 1;
383        CalendarCache::put(&gMonthCache, month, start, status);
384    }
385trueMonthStartEnd :
386    if(U_FAILURE(status)) {
387        start = 0;
388    }
389    return start;
390}
391
392/**
393* Return the "age" of the moon at the given time; this is the difference
394* in ecliptic latitude between the moon and the sun.  This method simply
395* calls CalendarAstronomer.moonAge, converts to degrees,
396* and adjusts the result to be in the range [-180, 180].
397*
398* @param time  The time at which the moon's age is desired,
399*              in millis since 1/1/1970.
400*/
401double IslamicCalendar::moonAge(UDate time, UErrorCode &status)
402{
403    double age = 0;
404
405    umtx_lock(&astroLock);
406    if(gIslamicCalendarAstro == NULL) {
407        gIslamicCalendarAstro = new CalendarAstronomer();
408        if (gIslamicCalendarAstro == NULL) {
409            status = U_MEMORY_ALLOCATION_ERROR;
410            return age;
411        }
412        ucln_i18n_registerCleanup(UCLN_I18N_ISLAMIC_CALENDAR, calendar_islamic_cleanup);
413    }
414    gIslamicCalendarAstro->setTime(time);
415    age = gIslamicCalendarAstro->getMoonAge();
416    umtx_unlock(&astroLock);
417
418    // Convert to degrees and normalize...
419    age = age * 180 / CalendarAstronomer::PI;
420    if (age > 180) {
421        age = age - 360;
422    }
423
424    return age;
425}
426
427//----------------------------------------------------------------------
428// Calendar framework
429//----------------------------------------------------------------------
430
431/**
432* Return the length (in days) of the given month.
433*
434* @param year  The hijri year
435* @param year  The hijri month, 0-based
436* @draft ICU 2.4
437*/
438int32_t IslamicCalendar::handleGetMonthLength(int32_t extendedYear, int32_t month) const {
439
440    int32_t length = 0;
441
442    if (cType == CIVIL || cType == TBLA ||
443        (cType == UMALQURA && (extendedYear<UMALQURA_YEAR_START || extendedYear>UMALQURA_YEAR_END)) ) {
444        length = 29 + (month+1) % 2;
445        if (month == DHU_AL_HIJJAH && civilLeapYear(extendedYear)) {
446            length++;
447        }
448    } else if(cType == ASTRONOMICAL){
449        month = 12*(extendedYear-1) + month;
450        length =  trueMonthStart(month+1) - trueMonthStart(month) ;
451    } else {
452        length = getUmalqura_MonthLength(extendedYear - UMALQURA_YEAR_START, month);
453    }
454    return length;
455}
456
457/**
458* Return the number of days in the given Islamic year
459* @draft ICU 2.4
460*/
461int32_t IslamicCalendar::handleGetYearLength(int32_t extendedYear) const {
462    if (cType == CIVIL || cType == TBLA ||
463        (cType == UMALQURA && (extendedYear<UMALQURA_YEAR_START || extendedYear>UMALQURA_YEAR_END)) ) {
464        return 354 + (civilLeapYear(extendedYear) ? 1 : 0);
465    } else if(cType == ASTRONOMICAL){
466        int32_t month = 12*(extendedYear-1);
467        return (trueMonthStart(month + 12) - trueMonthStart(month));
468    } else {
469        int len = 0;
470        for(int i=0; i<12; i++)
471            len += handleGetMonthLength(extendedYear, i);
472        return len;
473    }
474}
475
476//-------------------------------------------------------------------------
477// Functions for converting from field values to milliseconds....
478//-------------------------------------------------------------------------
479
480// Return JD of start of given month/year
481/**
482* @draft ICU 2.4
483*/
484int32_t IslamicCalendar::handleComputeMonthStart(int32_t eyear, int32_t month, UBool /* useMonth */) const {
485    return monthStart(eyear, month) + 1948439;
486}
487
488//-------------------------------------------------------------------------
489// Functions for converting from milliseconds to field values
490//-------------------------------------------------------------------------
491
492/**
493* @draft ICU 2.4
494*/
495int32_t IslamicCalendar::handleGetExtendedYear() {
496    int32_t year;
497    if (newerField(UCAL_EXTENDED_YEAR, UCAL_YEAR) == UCAL_EXTENDED_YEAR) {
498        year = internalGet(UCAL_EXTENDED_YEAR, 1); // Default to year 1
499    } else {
500        year = internalGet(UCAL_YEAR, 1); // Default to year 1
501    }
502    return year;
503}
504
505/**
506* Override Calendar to compute several fields specific to the Islamic
507* calendar system.  These are:
508*
509* <ul><li>ERA
510* <li>YEAR
511* <li>MONTH
512* <li>DAY_OF_MONTH
513* <li>DAY_OF_YEAR
514* <li>EXTENDED_YEAR</ul>
515*
516* The DAY_OF_WEEK and DOW_LOCAL fields are already set when this
517* method is called. The getGregorianXxx() methods return Gregorian
518* calendar equivalents for the given Julian day.
519* @draft ICU 2.4
520*/
521void IslamicCalendar::handleComputeFields(int32_t julianDay, UErrorCode &status) {
522    int32_t year, month, dayOfMonth, dayOfYear;
523    UDate startDate;
524    int32_t days = julianDay - CIVIL_EPOC;
525
526    if (cType == CIVIL || cType == TBLA) {
527        if(cType == TBLA)
528            days = julianDay - ASTRONOMICAL_EPOC;
529        // Use the civil calendar approximation, which is just arithmetic
530        year  = (int)ClockMath::floorDivide( (double)(30 * days + 10646) , 10631.0 );
531        month = (int32_t)uprv_ceil((days - 29 - yearStart(year)) / 29.5 );
532        month = month<11?month:11;
533        startDate = monthStart(year, month);
534    } else if(cType == ASTRONOMICAL){
535        // Guess at the number of elapsed full months since the epoch
536        int32_t months = (int32_t)uprv_floor((double)days / CalendarAstronomer::SYNODIC_MONTH);
537
538        startDate = uprv_floor(months * CalendarAstronomer::SYNODIC_MONTH);
539
540        double age = moonAge(internalGetTime(), status);
541        if (U_FAILURE(status)) {
542            status = U_MEMORY_ALLOCATION_ERROR;
543            return;
544        }
545        if ( days - startDate >= 25 && age > 0) {
546            // If we're near the end of the month, assume next month and search backwards
547            months++;
548        }
549
550        // Find out the last time that the new moon was actually visible at this longitude
551        // This returns midnight the night that the moon was visible at sunset.
552        while ((startDate = trueMonthStart(months)) > days) {
553            // If it was after the date in question, back up a month and try again
554            months--;
555        }
556
557        year = months / 12 + 1;
558        month = months % 12;
559    } else if(cType == UMALQURA) {
560        int32_t umalquraStartdays = yearStart(UMALQURA_YEAR_START) ;
561        if( days < umalquraStartdays){
562                //Use Civil calculation
563                year  = (int)ClockMath::floorDivide( (double)(30 * days + 10646) , 10631.0 );
564                month = (int32_t)uprv_ceil((days - 29 - yearStart(year)) / 29.5 );
565                month = month<11?month:11;
566                startDate = monthStart(year, month);
567            }else{
568                int y =UMALQURA_YEAR_START-1, m =0;
569                long d = 1;
570                while(d > 0){
571                    y++;
572                    d = days - yearStart(y) +1;
573                    if(d == handleGetYearLength(y)){
574                        m=11;
575                        break;
576                    }else if(d < handleGetYearLength(y) ){
577                        int monthLen = handleGetMonthLength(y, m);
578                        m=0;
579                        while(d > monthLen){
580                            d -= monthLen;
581                            m++;
582                            monthLen = handleGetMonthLength(y, m);
583                        }
584                        break;
585                    }
586                }
587                year = y;
588                month = m;
589            }
590    } else { // invalid 'civil'
591      U_ASSERT(false); // should not get here, out of range
592      year=month=0;
593    }
594
595    dayOfMonth = (days - monthStart(year, month)) + 1;
596
597    // Now figure out the day of the year.
598    dayOfYear = (days - monthStart(year, 0) + 1);
599
600
601    internalSet(UCAL_ERA, 0);
602    internalSet(UCAL_YEAR, year);
603    internalSet(UCAL_EXTENDED_YEAR, year);
604    internalSet(UCAL_MONTH, month);
605    internalSet(UCAL_DAY_OF_MONTH, dayOfMonth);
606    internalSet(UCAL_DAY_OF_YEAR, dayOfYear);
607}
608
609UBool
610IslamicCalendar::inDaylightTime(UErrorCode& status) const
611{
612    // copied from GregorianCalendar
613    if (U_FAILURE(status) || (&(getTimeZone()) == NULL && !getTimeZone().useDaylightTime()))
614        return FALSE;
615
616    // Force an update of the state of the Calendar.
617    ((IslamicCalendar*)this)->complete(status); // cast away const
618
619    return (UBool)(U_SUCCESS(status) ? (internalGet(UCAL_DST_OFFSET) != 0) : FALSE);
620}
621
622/**
623 * The system maintains a static default century start date and Year.  They are
624 * initialized the first time they are used.  Once the system default century date
625 * and year are set, they do not change.
626 */
627static UDate           gSystemDefaultCenturyStart       = DBL_MIN;
628static int32_t         gSystemDefaultCenturyStartYear   = -1;
629static icu::UInitOnce  gSystemDefaultCenturyInit        = U_INITONCE_INITIALIZER;
630
631
632UBool IslamicCalendar::haveDefaultCentury() const
633{
634    return TRUE;
635}
636
637UDate IslamicCalendar::defaultCenturyStart() const
638{
639    // lazy-evaluate systemDefaultCenturyStart
640    umtx_initOnce(gSystemDefaultCenturyInit, &initializeSystemDefaultCentury);
641    return gSystemDefaultCenturyStart;
642}
643
644int32_t IslamicCalendar::defaultCenturyStartYear() const
645{
646    // lazy-evaluate systemDefaultCenturyStartYear
647    umtx_initOnce(gSystemDefaultCenturyInit, &initializeSystemDefaultCentury);
648    return gSystemDefaultCenturyStartYear;
649}
650
651
652void U_CALLCONV
653IslamicCalendar::initializeSystemDefaultCentury()
654{
655    // initialize systemDefaultCentury and systemDefaultCenturyYear based
656    // on the current time.  They'll be set to 80 years before
657    // the current time.
658    UErrorCode status = U_ZERO_ERROR;
659    IslamicCalendar calendar(Locale("@calendar=islamic-civil"),status);
660    if (U_SUCCESS(status)) {
661        calendar.setTime(Calendar::getNow(), status);
662        calendar.add(UCAL_YEAR, -80, status);
663
664        gSystemDefaultCenturyStart = calendar.getTime(status);
665        gSystemDefaultCenturyStartYear = calendar.get(UCAL_YEAR, status);
666    }
667    // We have no recourse upon failure unless we want to propagate the failure
668    // out.
669}
670
671
672
673UOBJECT_DEFINE_RTTI_IMPLEMENTATION(IslamicCalendar)
674
675U_NAMESPACE_END
676
677#endif
678
679