i18npool/source/calendar/calendar_hijri.cxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
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   9  * This file incorporates work covered by the following license notice:
  10  *
  11  *   Licensed to the Apache Software Foundation (ASF) under one or more
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  13  *   with this work for additional information regarding copyright
  14  *   ownership. The ASF licenses this file to you under the Apache
  15  *   License, Version 2.0 (the "License"); you may not use this file
  16  *   except in compliance with the License. You may obtain a copy of
  17  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  18  */
  19
  20 #include <sal/config.h>
  21
  22 #include <cmath>
  23 #include <stdlib.h>
  24
  25 #include <calendar_hijri.hxx>
  26
  27 using namespace ::com::sun::star::uno;
  28 using namespace ::com::sun::star::lang;
  29 using namespace ::com::sun::star::i18n;
  30
  31 #define GREGORIAN_CROSSOVER 2299161
  32
  33 namespace i18npool {
  34
  35 // not used
  36 //static UErrorCode status; // status is shared in all calls to Calendar, it has to be reset for each call.
  37
  38 // radians per degree (pi/180)
  39 const double Calendar_hijri::RadPerDeg      = 0.01745329251994329577;
  40
  41 // Synodic Period (mean time between 2 successive new moon: 29d, 12 hr, 44min, 3sec
  42 const double Calendar_hijri::SynPeriod      = 29.53058868;
  43 const double Calendar_hijri::SynMonth       = 365.25/29.53058868;   // Solar days in a year/SynPeriod
  44
  45 // Julian day on Jan 1, 1900
  46 const double Calendar_hijri::jd1900     = 2415020.75933;
  47
  48 // Reference point: March 26, 2001 == 1422 Hijri == 1252 Synodial month from 1900
  49 const sal_Int32 Calendar_hijri::SynRef      = 1252;
  50 const sal_Int32 Calendar_hijri::GregRef     = 1422;
  51
  52 // Local time specific to Saudi Arabia
  53 const double Calendar_hijri::SA_TimeZone    = 3.0;
  54
  55 const double Calendar_hijri::EveningPeriod  = 6.0;
  56
  57 const sal_Int32 Calendar_hijri::LeapYear[] = {
  58     2, 5, 7, 10, 13, 16, 18, 21, 24, 26, 29
  59 };
  60
  61 Calendar_hijri::Calendar_hijri()
  62 {
  63     cCalendar = "com.sun.star.i18n.Calendar_hijri";
  64 }
  65
  66 #define FIELDS  ((1 << CalendarFieldIndex::ERA) | (1 << CalendarFieldIndex::YEAR) | (1 << CalendarFieldIndex::MONTH) | (1 << CalendarFieldIndex::DAY_OF_MONTH))
  67
  68 // map field value from hijri calendar to gregorian calendar
  69 void Calendar_hijri::mapToGregorian()
  70 {
  71     if (fieldSet & FIELDS) {
  72         sal_Int32 day = static_cast<sal_Int32>(fieldSetValue[CalendarFieldIndex::DAY_OF_MONTH]);
  73         sal_Int32 month = static_cast<sal_Int32>(fieldSetValue[CalendarFieldIndex::MONTH]) + 1;
  74         sal_Int32 year = static_cast<sal_Int32>(fieldSetValue[CalendarFieldIndex::YEAR]);
  75         if (fieldSetValue[CalendarFieldIndex::ERA] == 0)
  76             year *= -1;
  77
  78         ToGregorian(&day, &month, &year);
  79
  80         fieldSetValue[CalendarFieldIndex::ERA] = year <= 0 ? 0 : 1;
  81         fieldSetValue[CalendarFieldIndex::MONTH] = sal::static_int_cast<sal_Int16>(month - 1);
  82         fieldSetValue[CalendarFieldIndex::DAY_OF_MONTH] = static_cast<sal_Int16>(day);
  83         fieldSetValue[CalendarFieldIndex::YEAR] = static_cast<sal_Int16>(abs(year));
  84         fieldSet |= FIELDS;
  85     }
  86 }
  87
  88 // map field value from gregorian calendar to hijri calendar
  89 void Calendar_hijri::mapFromGregorian()
  90 {
  91     sal_Int32 month, day, year;
  92
  93     day = static_cast<sal_Int32>(fieldValue[CalendarFieldIndex::DAY_OF_MONTH]);
  94     month = static_cast<sal_Int32>(fieldValue[CalendarFieldIndex::MONTH]) + 1;
  95     year = static_cast<sal_Int32>(fieldValue[CalendarFieldIndex::YEAR]);
  96     if (fieldValue[CalendarFieldIndex::ERA] == 0)
  97         year *= -1;
  98
  99     // Get Hijri date
 100     getHijri(&day, &month, &year);
 101
 102     fieldValue[CalendarFieldIndex::DAY_OF_MONTH] = static_cast<sal_Int16>(day);
 103     fieldValue[CalendarFieldIndex::MONTH] = sal::static_int_cast<sal_Int16>(month - 1);
 104     fieldValue[CalendarFieldIndex::YEAR] = static_cast<sal_Int16>(abs(year));
 105     fieldValue[CalendarFieldIndex::ERA] = static_cast<sal_Int16>(year) < 1 ? 0 : 1;
 106 }
 107
 108
 109 // This function returns the Julian date/time of the Nth new moon since
 110 // January 1900.  The synodic month is passed as parameter.
 111
 112 // Adapted from "Astronomical  Formulae for Calculators" by
 113 // Jean Meeus, Third Edition, Willmann-Bell, 1985.
 114
 115 double
 116 Calendar_hijri::NewMoon(sal_Int32 n)
 117 {
 118     double jd, t, t2, t3, k, ma, sa, tf, xtra;
 119     k = n;
 120     t = k/1236.85;  // Time in Julian centuries from 1900 January 0.5
 121     t2 = t * t;
 122     t3 = t2 * t;
 123
 124     // Mean time of phase
 125     jd =  jd1900
 126         + SynPeriod * k
 127         - 0.0001178 * t2
 128         - 0.000000155 * t3
 129         + 0.00033 * sin(RadPerDeg * (166.56 + 132.87 * t - 0.009173 * t2));
 130
 131     // Sun's mean anomaly in radian
 132     sa =  RadPerDeg * (359.2242
 133                 + 29.10535608 * k
 134                 - 0.0000333 * t2
 135                 - 0.00000347 * t3);
 136
 137     // Moon's mean anomaly
 138     ma =  RadPerDeg * (306.0253
 139                 + 385.81691806 * k
 140                 + 0.0107306 * t2
 141                 + 0.00001236 * t3);
 142
 143     // Moon's argument of latitude
 144     tf = RadPerDeg * 2.0 * (21.2964
 145                 + 390.67050646 * k
 146                 - 0.0016528 * t2
 147                 - 0.00000239 * t3);
 148
 149     // should reduce to interval between 0 to 1.0 before calculating further
 150     // Corrections for New Moon
 151     xtra = (0.1734 - 0.000393 * t) * sin(sa)
 152         + 0.0021 * sin(sa * 2)
 153         - 0.4068 * sin(ma)
 154         + 0.0161 * sin(2 * ma)
 155         - 0.0004 * sin(3 * ma)
 156         + 0.0104 * sin(tf)
 157         - 0.0051 * sin(sa + ma)
 158         - 0.0074 * sin(sa - ma)
 159         + 0.0004 * sin(tf + sa)
 160         - 0.0004 * sin(tf - sa)
 161         - 0.0006 * sin(tf + ma)
 162         + 0.0010 * sin(tf - ma)
 163         + 0.0005 * sin(sa + 2 * ma);
 164
 165     // convert from Ephemeris Time (ET) to (approximate) Universal Time (UT)
 166     jd += xtra - (0.41 + 1.2053 * t + 0.4992 * t2)/1440;
 167
 168     return jd;
 169 }
 170
 171 // Get Hijri Date
 172 void
 173 Calendar_hijri::getHijri(sal_Int32 *day, sal_Int32 *month, sal_Int32 *year)
 174 {
 175     double prevday;
 176 //  double dayfraction;
 177     sal_Int32 syndiff;
 178     sal_Int32 newsyn;
 179     double newjd;
 180     sal_Int32 synmonth;
 181
 182     // Get Julian Day from Gregorian
 183     sal_Int32 const julday = getJulianDay(*day, *month, *year);
 184
 185     // obtain approx. of how many Synodic months since the beginning of the year 1900
 186     synmonth = static_cast<sal_Int32>(0.5 + (julday - jd1900)/SynPeriod);
 187
 188     newsyn = synmonth;
 189     prevday = julday - 0.5;
 190
 191     do {
 192         newjd = NewMoon(newsyn);
 193
 194         // Decrement syntonic months
 195         newsyn--;
 196     } while (newjd > prevday);
 197     newsyn++;
 198
 199     // difference from reference point
 200     syndiff = newsyn - SynRef;
 201
 202     // Round up the day
 203     *day = static_cast<sal_Int32>(julday - newjd + 0.5);
 204     *month =  (syndiff % 12) + 1;
 205
 206     // currently not supported
 207     //dayOfYear = (sal_Int32)(month * SynPeriod + day);
 208     *year = GregRef + static_cast<sal_Int32>(syndiff / 12);
 209
 210     // If month negative, consider it previous year
 211     if (syndiff != 0 && *month <= 0) {
 212         *month += 12;
 213         (*year)--;
 214     }
 215
 216     // If Before Hijri subtract 1
 217     if (*year <= 0) (*year)--;
 218 }
 219
 220 void
 221 Calendar_hijri::ToGregorian(sal_Int32 *day, sal_Int32 *month, sal_Int32 *year)
 222 {
 223     sal_Int32 nmonth;
 224 //    double dayfraction;
 225     double jday;
 226 //    sal_Int32 dayint;
 227
 228     if ( *year < 0 ) (*year)++;
 229
 230     // Number of month from reference point
 231     nmonth = *month + *year * 12 - (GregRef * 12 + 1);
 232
 233     // Add Synodic Reference point
 234     nmonth += SynRef;
 235
 236     // Get Julian days add time too
 237     jday = NewMoon(nmonth) + *day;
 238
 239     // Round-up
 240     jday = std::trunc(jday + 0.5);
 241
 242     // Use algorithm from "Numerical Recipes in C"
 243     getGregorianDay(static_cast<sal_Int32>(jday), day, month, year);
 244
 245     // Julian -> Gregorian only works for non-negative year
 246     if ( *year <= 0 ) {
 247     *day = -1;
 248     *month = -1;
 249     *year = -1;
 250     }
 251 }
 252
 253 /* this algorithm is taken from "Numerical Recipes in C", 2nd ed, pp 14-15. */
 254 /* this algorithm only valid for non-negative gregorian year                */
 255 void
 256 Calendar_hijri::getGregorianDay(sal_Int32 lJulianDay, sal_Int32 *pnDay, sal_Int32 *pnMonth, sal_Int32 *pnYear)
 257 {
 258     /* working variables */
 259     long lFactorA, lFactorB, lFactorC, lFactorD, lFactorE;
 260
 261     /* test whether to adjust for the Gregorian calendar crossover */
 262     if (lJulianDay >= GREGORIAN_CROSSOVER) {
 263     /* calculate a small adjustment */
 264     long lAdjust = static_cast<long>((static_cast<float>(lJulianDay - 1867216) - 0.25) / 36524.25);
 265
 266     lFactorA = lJulianDay + 1 + lAdjust - static_cast<long>(0.25 * lAdjust);
 267
 268     } else {
 269     /* no adjustment needed */
 270     lFactorA = lJulianDay;
 271     }
 272
 273     lFactorB = lFactorA + 1524;
 274     lFactorC = static_cast<long>(6680.0 + (static_cast<float>(lFactorB - 2439870) - 122.1) / 365.25);
 275     lFactorD = static_cast<long>(365 * lFactorC + (0.25 * lFactorC));
 276     lFactorE = static_cast<long>((lFactorB - lFactorD) / 30.6001);
 277
 278     /* now, pull out the day number */
 279     *pnDay = lFactorB - lFactorD - static_cast<long>(30.6001 * lFactorE);
 280
 281     /* ...and the month, adjusting it if necessary */
 282     *pnMonth = lFactorE - 1;
 283     if (*pnMonth > 12)
 284         (*pnMonth) -= 12;
 285
 286     /* ...and similarly for the year */
 287     *pnYear = lFactorC - 4715;
 288     if (*pnMonth > 2)
 289         (*pnYear)--;
 290
 291     // Negative year adjustments
 292     if (*pnYear <= 0)
 293         (*pnYear)--;
 294 }
 295
 296 sal_Int32
 297 Calendar_hijri::getJulianDay(sal_Int32 day, sal_Int32 month, sal_Int32 year)
 298 {
 299     double jy, jm;
 300
 301     if( year == 0 ) {
 302     return -1;
 303     }
 304
 305     if( year == 1582 && month == 10 && day > 4 && day < 15 ) {
 306     return -1;
 307     }
 308
 309     if( month > 2 ) {
 310     jy = year;
 311     jm = month + 1;
 312     } else {
 313     jy = year - 1;
 314     jm = month + 13;
 315     }
 316
 317     sal_Int32 intgr = static_cast<sal_Int32>(static_cast<sal_Int32>(365.25 * jy) + static_cast<sal_Int32>(30.6001 * jm) + day + 1720995 );
 318
 319     //check for switch to Gregorian calendar
 320     double const gregcal = 15 + 31 * ( 10 + 12 * 1582 );
 321
 322     if( day + 31 * (month + 12 * year) >= gregcal ) {
 323         double ja;
 324         ja = std::trunc(0.01 * jy);
 325         intgr += static_cast<sal_Int32>(2 - ja + std::trunc(0.25 * ja));
 326     }
 327
 328     return intgr;
 329 }
 330
 331 }
 332
 333 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */