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