icuSources/i18n/islamcal.cpp

   1 /*
   2 ******************************************************************************
   3 * Copyright (C) 2003-2008, 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
  27 static const UDate HIJRA_MILLIS = -42521587200000.0;    // 7/16/622 AD 00:00
  28
  29 // Debugging
  30 #ifdef U_DEBUG_ISLAMCAL
  31 # include <stdio.h>
  32 # include <stdarg.h>
  33 static void debug_islamcal_loc(const char *f, int32_t l)
  34 {
  35     fprintf(stderr, "%s:%d: ", f, l);
  36 }
  37
  38 static void debug_islamcal_msg(const char *pat, ...)
  39 {
  40     va_list ap;
  41     va_start(ap, pat);
  42     vfprintf(stderr, pat, ap);
  43     fflush(stderr);
  44 }
  45 // must use double parens, i.e.:  U_DEBUG_ISLAMCAL_MSG(("four is: %d",4));
  46 #define U_DEBUG_ISLAMCAL_MSG(x) {debug_islamcal_loc(__FILE__,__LINE__);debug_islamcal_msg x;}
  47 #else
  48 #define U_DEBUG_ISLAMCAL_MSG(x)
  49 #endif
  50
  51
  52 // --- The cache --
  53 // cache of months
  54 static UMTX astroLock = 0;  // pod bay door lock
  55 static U_NAMESPACE_QUALIFIER CalendarCache *gMonthCache = NULL;
  56 static U_NAMESPACE_QUALIFIER CalendarAstronomer *gIslamicCalendarAstro = NULL;
  57
  58 U_CDECL_BEGIN
  59 static UBool calendar_islamic_cleanup(void) {
  60     if (gMonthCache) {
  61         delete gMonthCache;
  62         gMonthCache = NULL;
  63     }
  64     if (gIslamicCalendarAstro) {
  65         delete gIslamicCalendarAstro;
  66         gIslamicCalendarAstro = NULL;
  67     }
  68     umtx_destroy(&astroLock);
  69     return TRUE;
  70 }
  71 U_CDECL_END
  72
  73 U_NAMESPACE_BEGIN
  74
  75 // Implementation of the IslamicCalendar class
  76
  77 //-------------------------------------------------------------------------
  78 // Constructors...
  79 //-------------------------------------------------------------------------
  80
  81 const char *IslamicCalendar::getType() const {
  82     if(civil==CIVIL) {
  83         return "islamic-civil";
  84     } else {
  85         return "islamic";
  86     }
  87 }
  88
  89 Calendar* IslamicCalendar::clone() const {
  90     return new IslamicCalendar(*this);
  91 }
  92
  93 IslamicCalendar::IslamicCalendar(const Locale& aLocale, UErrorCode& success, ECivil beCivil)
  94 :   Calendar(TimeZone::createDefault(), aLocale, success),
  95 civil(beCivil)
  96 {
  97     setTimeInMillis(getNow(), success); // Call this again now that the vtable is set up properly.
  98 }
  99
 100 IslamicCalendar::IslamicCalendar(const IslamicCalendar& other) : Calendar(other), civil(other.civil) {
 101 }
 102
 103 IslamicCalendar::~IslamicCalendar()
 104 {
 105 }
 106
 107 /**
 108 * Determines whether this object uses the fixed-cycle Islamic civil calendar
 109 * or an approximation of the religious, astronomical calendar.
 110 *
 111 * @param beCivil   <code>true</code> to use the civil calendar,
 112 *                  <code>false</code> to use the astronomical calendar.
 113 * @draft ICU 2.4
 114 */
 115 void IslamicCalendar::setCivil(ECivil beCivil, UErrorCode &status)
 116 {
 117     if (civil != beCivil) {
 118         // The fields of the calendar will become invalid, because the calendar
 119         // rules are different
 120         UDate m = getTimeInMillis(status);
 121         civil = beCivil;
 122         clear();
 123         setTimeInMillis(m, status);
 124     }
 125 }
 126
 127 /**
 128 * Returns <code>true</code> if this object is using the fixed-cycle civil
 129 * calendar, or <code>false</code> if using the religious, astronomical
 130 * calendar.
 131 * @draft ICU 2.4
 132 */
 133 UBool IslamicCalendar::isCivil() {
 134     return (civil == CIVIL);
 135 }
 136
 137 //-------------------------------------------------------------------------
 138 // Minimum / Maximum access functions
 139 //-------------------------------------------------------------------------
 140
 141 // Note: Current IslamicCalendar implementation does not work
 142 // well with negative years.
 143
 144 static const int32_t LIMITS[UCAL_FIELD_COUNT][4] = {
 145     // Minimum  Greatest    Least  Maximum
 146     //           Minimum  Maximum
 147     {        0,        0,        0,        0}, // ERA
 148     {        1,        1,  5000000,  5000000}, // YEAR
 149     {        0,        0,       11,       11}, // MONTH
 150     {        1,        1,       50,       51}, // WEEK_OF_YEAR
 151     {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // WEEK_OF_MONTH
 152     {        1,        1,       29,       31}, // DAY_OF_MONTH (**** SB 30 ****)
 153     {        1,        1,      354,      355}, // DAY_OF_YEAR
 154     {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // DAY_OF_WEEK
 155     {       -1,       -1,        5,        5}, // DAY_OF_WEEK_IN_MONTH
 156     {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // AM_PM
 157     {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // HOUR
 158     {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // HOUR_OF_DAY
 159     {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // MINUTE
 160     {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // SECOND
 161     {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // MILLISECOND
 162     {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // ZONE_OFFSET
 163     {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // DST_OFFSET
 164     {        1,        1,  5000000,  5000000}, // YEAR_WOY
 165     {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // DOW_LOCAL
 166     {        1,        1,  5000000,  5000000}, // EXTENDED_YEAR
 167     {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // JULIAN_DAY
 168     {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // MILLISECONDS_IN_DAY
 169     {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // IS_LEAP_MONTH
 170 };
 171
 172 /**
 173 * @draft ICU 2.4
 174 */
 175 int32_t IslamicCalendar::handleGetLimit(UCalendarDateFields field, ELimitType limitType) const {
 176     return LIMITS[field][limitType];
 177 }
 178
 179 //-------------------------------------------------------------------------
 180 // Assorted calculation utilities
 181 //
 182
 183 /**
 184 * Determine whether a year is a leap year in the Islamic civil calendar
 185 */
 186 UBool IslamicCalendar::civilLeapYear(int32_t year)
 187 {
 188     return (14 + 11 * year) % 30 < 11;
 189 }
 190
 191 /**
 192 * Return the day # on which the given year starts.  Days are counted
 193 * from the Hijri epoch, origin 0.
 194 */
 195 int32_t IslamicCalendar::yearStart(int32_t year) {
 196     if (civil == CIVIL) {
 197         return (year-1)*354 + Math::floorDivide((3+11*year),30);
 198     } else {
 199         return trueMonthStart(12*(year-1));
 200     }
 201 }
 202
 203 /**
 204 * Return the day # on which the given month starts.  Days are counted
 205 * from the Hijri epoch, origin 0.
 206 *
 207 * @param year  The hijri year
 208 * @param year  The hijri month, 0-based
 209 */
 210 int32_t IslamicCalendar::monthStart(int32_t year, int32_t month) const {
 211     if (civil == CIVIL) {
 212         return (int32_t)uprv_ceil(29.5*month)
 213             + (year-1)*354 + (int32_t)Math::floorDivide((3+11*year),30);
 214     } else {
 215         return trueMonthStart(12*(year-1) + month);
 216     }
 217 }
 218
 219 /**
 220 * Find the day number on which a particular month of the true/lunar
 221 * Islamic calendar starts.
 222 *
 223 * @param month The month in question, origin 0 from the Hijri epoch
 224 *
 225 * @return The day number on which the given month starts.
 226 */
 227 int32_t IslamicCalendar::trueMonthStart(int32_t month) const
 228 {
 229     UErrorCode status = U_ZERO_ERROR;
 230     int32_t start = CalendarCache::get(&gMonthCache, month, status);
 231
 232     if (start==0) {
 233         // Make a guess at when the month started, using the average length
 234         UDate origin = HIJRA_MILLIS
 235             + uprv_floor(month * CalendarAstronomer::SYNODIC_MONTH - 1) * kOneDay;
 236
 237         // moonAge will fail due to memory allocation error
 238         double age = moonAge(origin, status);
 239         if (U_FAILURE(status)) {
 240             goto trueMonthStartEnd;
 241         }
 242
 243         if (age >= 0) {
 244             // The month has already started
 245             do {
 246                 origin -= kOneDay;
 247                 age = moonAge(origin, status);
 248                 if (U_FAILURE(status)) {
 249                     goto trueMonthStartEnd;
 250                 }
 251             } while (age >= 0);
 252         }
 253         else {
 254             // Preceding month has not ended yet.
 255             do {
 256                 origin += kOneDay;
 257                 age = moonAge(origin, status);
 258                 if (U_FAILURE(status)) {
 259                     goto trueMonthStartEnd;
 260                 }
 261             } while (age < 0);
 262         }
 263         start = (int32_t)Math::floorDivide((origin - HIJRA_MILLIS), (double)kOneDay) + 1;
 264         CalendarCache::put(&gMonthCache, month, start, status);
 265     }
 266 trueMonthStartEnd :
 267     if(U_FAILURE(status)) {
 268         start = 0;
 269     }
 270     return start;
 271 }
 272
 273 /**
 274 * Return the "age" of the moon at the given time; this is the difference
 275 * in ecliptic latitude between the moon and the sun.  This method simply
 276 * calls CalendarAstronomer.moonAge, converts to degrees,
 277 * and adjusts the result to be in the range [-180, 180].
 278 *
 279 * @param time  The time at which the moon's age is desired,
 280 *              in millis since 1/1/1970.
 281 */
 282 double IslamicCalendar::moonAge(UDate time, UErrorCode &status)
 283 {
 284     double age = 0;
 285
 286     umtx_lock(&astroLock);
 287     if(gIslamicCalendarAstro == NULL) {
 288         gIslamicCalendarAstro = new CalendarAstronomer();
 289         if (gIslamicCalendarAstro == NULL) {
 290             status = U_MEMORY_ALLOCATION_ERROR;
 291             return age;
 292         }
 293         ucln_i18n_registerCleanup(UCLN_I18N_ISLAMIC_CALENDAR, calendar_islamic_cleanup);
 294     }
 295     gIslamicCalendarAstro->setTime(time);
 296     age = gIslamicCalendarAstro->getMoonAge();
 297     umtx_unlock(&astroLock);
 298
 299     // Convert to degrees and normalize...
 300     age = age * 180 / CalendarAstronomer::PI;
 301     if (age > 180) {
 302         age = age - 360;
 303     }
 304
 305     return age;
 306 }
 307
 308 //----------------------------------------------------------------------
 309 // Calendar framework
 310 //----------------------------------------------------------------------
 311
 312 /**
 313 * Return the length (in days) of the given month.
 314 *
 315 * @param year  The hijri year
 316 * @param year  The hijri month, 0-based
 317 * @draft ICU 2.4
 318 */
 319 int32_t IslamicCalendar::handleGetMonthLength(int32_t extendedYear, int32_t month) const {
 320
 321     int32_t length = 0;
 322
 323     if (civil == CIVIL) {
 324         length = 29 + (month+1) % 2;
 325         if (month == DHU_AL_HIJJAH && civilLeapYear(extendedYear)) {
 326             length++;
 327         }
 328     } else {
 329         month = 12*(extendedYear-1) + month;
 330         length =  trueMonthStart(month+1) - trueMonthStart(month) ;
 331     }
 332     return length;
 333 }
 334
 335 /**
 336 * Return the number of days in the given Islamic year
 337 * @draft ICU 2.4
 338 */
 339 int32_t IslamicCalendar::handleGetYearLength(int32_t extendedYear) const {
 340     if (civil == CIVIL) {
 341         return 354 + (civilLeapYear(extendedYear) ? 1 : 0);
 342     } else {
 343         int32_t month = 12*(extendedYear-1);
 344         return (trueMonthStart(month + 12) - trueMonthStart(month));
 345     }
 346 }
 347
 348 //-------------------------------------------------------------------------
 349 // Functions for converting from field values to milliseconds....
 350 //-------------------------------------------------------------------------
 351
 352 // Return JD of start of given month/year
 353 /**
 354 * @draft ICU 2.4
 355 */
 356 int32_t IslamicCalendar::handleComputeMonthStart(int32_t eyear, int32_t month, UBool /* useMonth */) const {
 357     return monthStart(eyear, month) + 1948439;
 358 }
 359
 360 //-------------------------------------------------------------------------
 361 // Functions for converting from milliseconds to field values
 362 //-------------------------------------------------------------------------
 363
 364 /**
 365 * @draft ICU 2.4
 366 */
 367 int32_t IslamicCalendar::handleGetExtendedYear() {
 368     int32_t year;
 369     if (newerField(UCAL_EXTENDED_YEAR, UCAL_YEAR) == UCAL_EXTENDED_YEAR) {
 370         year = internalGet(UCAL_EXTENDED_YEAR, 1); // Default to year 1
 371     } else {
 372         year = internalGet(UCAL_YEAR, 1); // Default to year 1
 373     }
 374     return year;
 375 }
 376
 377 /**
 378 * Override Calendar to compute several fields specific to the Islamic
 379 * calendar system.  These are:
 380 *
 381 * <ul><li>ERA
 382 * <li>YEAR
 383 * <li>MONTH
 384 * <li>DAY_OF_MONTH
 385 * <li>DAY_OF_YEAR
 386 * <li>EXTENDED_YEAR</ul>
 387 *
 388 * The DAY_OF_WEEK and DOW_LOCAL fields are already set when this
 389 * method is called. The getGregorianXxx() methods return Gregorian
 390 * calendar equivalents for the given Julian day.
 391 * @draft ICU 2.4
 392 */
 393 void IslamicCalendar::handleComputeFields(int32_t julianDay, UErrorCode &status) {
 394     int32_t year, month, dayOfMonth, dayOfYear;
 395     UDate startDate;
 396     int32_t days = julianDay - 1948440;
 397
 398     if (civil == CIVIL) {
 399         // Use the civil calendar approximation, which is just arithmetic
 400         year  = (int)Math::floorDivide( (double)(30 * days + 10646) , 10631.0 );
 401         month = (int32_t)uprv_ceil((days - 29 - yearStart(year)) / 29.5 );
 402         month = month<11?month:11;
 403         startDate = monthStart(year, month);
 404     } else {
 405         // Guess at the number of elapsed full months since the epoch
 406         int32_t months = (int32_t)uprv_floor((double)days / CalendarAstronomer::SYNODIC_MONTH);
 407
 408         startDate = uprv_floor(months * CalendarAstronomer::SYNODIC_MONTH - 1);
 409
 410         double age = moonAge(internalGetTime(), status);
 411         if (U_FAILURE(status)) {
 412                 status = U_MEMORY_ALLOCATION_ERROR;
 413                 return;
 414         }
 415         if ( days - startDate >= 28 && age > 0) {
 416             // If we're near the end of the month, assume next month and search backwards
 417             months++;
 418         }
 419
 420         // Find out the last time that the new moon was actually visible at this longitude
 421         // This returns midnight the night that the moon was visible at sunset.
 422         while ((startDate = trueMonthStart(months)) > days) {
 423             // If it was after the date in question, back up a month and try again
 424             months--;
 425         }
 426
 427         year = months / 12 + 1;
 428         month = months % 12;
 429     }
 430
 431     dayOfMonth = (days - monthStart(year, month)) + 1;
 432
 433     // Now figure out the day of the year.
 434     dayOfYear = (days - monthStart(year, 0) + 1);
 435
 436     internalSet(UCAL_ERA, 0);
 437     internalSet(UCAL_YEAR, year);
 438     internalSet(UCAL_EXTENDED_YEAR, year);
 439     internalSet(UCAL_MONTH, month);
 440     internalSet(UCAL_DAY_OF_MONTH, dayOfMonth);
 441     internalSet(UCAL_DAY_OF_YEAR, dayOfYear);
 442 }
 443
 444 UBool
 445 IslamicCalendar::inDaylightTime(UErrorCode& status) const
 446 {
 447     // copied from GregorianCalendar
 448     if (U_FAILURE(status) || (&(getTimeZone()) == NULL && !getTimeZone().useDaylightTime()))
 449         return FALSE;
 450
 451     // Force an update of the state of the Calendar.
 452     ((IslamicCalendar*)this)->complete(status); // cast away const
 453
 454     return (UBool)(U_SUCCESS(status) ? (internalGet(UCAL_DST_OFFSET) != 0) : FALSE);
 455 }
 456
 457 // default century
 458 const UDate     IslamicCalendar::fgSystemDefaultCentury        = DBL_MIN;
 459 const int32_t   IslamicCalendar::fgSystemDefaultCenturyYear    = -1;
 460
 461 UDate           IslamicCalendar::fgSystemDefaultCenturyStart       = DBL_MIN;
 462 int32_t         IslamicCalendar::fgSystemDefaultCenturyStartYear   = -1;
 463
 464
 465 UBool IslamicCalendar::haveDefaultCentury() const
 466 {
 467     return TRUE;
 468 }
 469
 470 UDate IslamicCalendar::defaultCenturyStart() const
 471 {
 472     return internalGetDefaultCenturyStart();
 473 }
 474
 475 int32_t IslamicCalendar::defaultCenturyStartYear() const
 476 {
 477     return internalGetDefaultCenturyStartYear();
 478 }
 479
 480 UDate
 481 IslamicCalendar::internalGetDefaultCenturyStart() const
 482 {
 483     // lazy-evaluate systemDefaultCenturyStart
 484     UBool needsUpdate;
 485     UMTX_CHECK(NULL, (fgSystemDefaultCenturyStart == fgSystemDefaultCentury), needsUpdate);
 486
 487     if (needsUpdate) {
 488         initializeSystemDefaultCentury();
 489     }
 490
 491     // use defaultCenturyStart unless it's the flag value;
 492     // then use systemDefaultCenturyStart
 493
 494     return fgSystemDefaultCenturyStart;
 495 }
 496
 497 int32_t
 498 IslamicCalendar::internalGetDefaultCenturyStartYear() const
 499 {
 500     // lazy-evaluate systemDefaultCenturyStartYear
 501     UBool needsUpdate;
 502     UMTX_CHECK(NULL, (fgSystemDefaultCenturyStart == fgSystemDefaultCentury), needsUpdate);
 503
 504     if (needsUpdate) {
 505         initializeSystemDefaultCentury();
 506     }
 507
 508     // use defaultCenturyStart unless it's the flag value;
 509     // then use systemDefaultCenturyStartYear
 510
 511     return    fgSystemDefaultCenturyStartYear;
 512 }
 513
 514 void
 515 IslamicCalendar::initializeSystemDefaultCentury()
 516 {
 517     // initialize systemDefaultCentury and systemDefaultCenturyYear based
 518     // on the current time.  They'll be set to 80 years before
 519     // the current time.
 520     // No point in locking as it should be idempotent.
 521     if (fgSystemDefaultCenturyStart == fgSystemDefaultCentury)
 522     {
 523         UErrorCode status = U_ZERO_ERROR;
 524         IslamicCalendar calendar(Locale("@calendar=islamic-civil"),status);
 525         if (U_SUCCESS(status))
 526         {
 527             calendar.setTime(Calendar::getNow(), status);
 528             calendar.add(UCAL_YEAR, -80, status);
 529             UDate    newStart =  calendar.getTime(status);
 530             int32_t  newYear  =  calendar.get(UCAL_YEAR, status);
 531             {
 532                 umtx_lock(NULL);
 533                 fgSystemDefaultCenturyStart = newStart;
 534                 fgSystemDefaultCenturyStartYear = newYear;
 535                 umtx_unlock(NULL);
 536             }
 537         }
 538         // We have no recourse upon failure unless we want to propagate the failure
 539         // out.
 540     }
 541 }
 542
 543 UOBJECT_DEFINE_RTTI_IMPLEMENTATION(IslamicCalendar)
 544
 545 U_NAMESPACE_END
 546
 547 #endif
 548