i18npool/source/calendar/calendar_hijri.cxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
   4  *
   5  * This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8  *
   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
  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
  21 #include <stdlib.h>
  22 #include <math.h>
  23
  24 #include <android/compatibility.hxx>
  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 = (sal_Int32)fieldSetValue[CalendarFieldIndex::DAY_OF_MONTH];
  74         sal_Int32 month = (sal_Int32)fieldSetValue[CalendarFieldIndex::MONTH] + 1;
  75         sal_Int32 year = (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] = (sal_Int16) day;
  84         fieldSetValue[CalendarFieldIndex::YEAR] = (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 = (sal_Int32)fieldValue[CalendarFieldIndex::DAY_OF_MONTH];
  95     month = (sal_Int32)fieldValue[CalendarFieldIndex::MONTH] + 1;
  96     year = (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] = (sal_Int16)day;
 104     fieldValue[CalendarFieldIndex::MONTH] = sal::static_int_cast<sal_Int16>(month - 1);
 105     fieldValue[CalendarFieldIndex::YEAR] = (sal_Int16) abs(year);
 106     fieldValue[CalendarFieldIndex::ERA] = (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     double julday;
 182     sal_Int32 synmonth;
 183
 184     // Get Julian Day from Gregorian
 185     julday = getJulianDay(*day, *month, *year);
 186
 187     // obtain approx. of how many Synodic months since the beginning of the year 1900
 188     synmonth = (sal_Int32)(0.5 + (julday - jd1900)/SynPeriod);
 189
 190     newsyn = synmonth;
 191     prevday = (sal_Int32)julday - 0.5;
 192
 193     do {
 194         newjd = NewMoon(newsyn);
 195
 196         // Decrement syntonic months
 197         newsyn--;
 198     } while (newjd > prevday);
 199     newsyn++;
 200
 201     // difference from reference point
 202     syndiff = newsyn - SynRef;
 203
 204     // Round up the day
 205     *day = (sal_Int32)(((sal_Int32)julday) - newjd + 0.5);
 206     *month =  (syndiff % 12) + 1;
 207
 208     // currently not supported
 209     //dayOfYear = (sal_Int32)(month * SynPeriod + day);
 210     *year = GregRef + (sal_Int32)(syndiff / 12);
 211
 212     // If month negative, consider it previous year
 213     if (syndiff != 0 && *month <= 0) {
 214         *month += 12;
 215         (*year)--;
 216     }
 217
 218     // If Before Hijri subtract 1
 219     if (*year <= 0) (*year)--;
 220 }
 221
 222 void
 223 Calendar_hijri::ToGregorian(sal_Int32 *day, sal_Int32 *month, sal_Int32 *year)
 224 {
 225     sal_Int32 nmonth;
 226 //    double dayfraction;
 227     double jday;
 228 //    sal_Int32 dayint;
 229
 230     if ( *year < 0 ) (*year)++;
 231
 232     // Number of month from reference point
 233     nmonth = *month + *year * 12 - (GregRef * 12 + 1);
 234
 235     // Add Synodic Reference point
 236     nmonth += SynRef;
 237
 238     // Get Julian days add time too
 239     jday = NewMoon(nmonth) + *day;
 240
 241     // Round-up
 242     jday = (double)((sal_Int32)(jday + 0.5));
 243
 244     // Use algorithm from "Numerical Recipes in C"
 245     getGregorianDay((sal_Int32)jday, day, month, year);
 246
 247     // Julian -> Gregorian only works for non-negative year
 248     if ( *year <= 0 ) {
 249     *day = -1;
 250     *month = -1;
 251     *year = -1;
 252     }
 253 }
 254
 255 /* this algorithm is taken from "Numerical Recipes in C", 2nd ed, pp 14-15. */
 256 /* this algorithm only valid for non-negative gregorian year                */
 257 void
 258 Calendar_hijri::getGregorianDay(sal_Int32 lJulianDay, sal_Int32 *pnDay, sal_Int32 *pnMonth, sal_Int32 *pnYear)
 259 {
 260     /* working variables */
 261     long lFactorA, lFactorB, lFactorC, lFactorD, lFactorE;
 262
 263     /* test whether to adjust for the Gregorian calendar crossover */
 264     if (lJulianDay >= GREGORIAN_CROSSOVER) {
 265     /* calculate a small adjustment */
 266     long lAdjust = (long) (((float) (lJulianDay - 1867216) - 0.25) / 36524.25);
 267
 268     lFactorA = lJulianDay + 1 + lAdjust - ((long) (0.25 * lAdjust));
 269
 270     } else {
 271     /* no adjustment needed */
 272     lFactorA = lJulianDay;
 273     }
 274
 275     lFactorB = lFactorA + 1524;
 276     lFactorC = (long) (6680.0 + ((float) (lFactorB - 2439870) - 122.1) / 365.25);
 277     lFactorD = (long) (365 * lFactorC + (0.25 * lFactorC));
 278     lFactorE = (long) ((lFactorB - lFactorD) / 30.6001);
 279
 280     /* now, pull out the day number */
 281     *pnDay = lFactorB - lFactorD - (long) (30.6001 * lFactorE);
 282
 283     /* ...and the month, adjusting it if necessary */
 284     *pnMonth = lFactorE - 1;
 285     if (*pnMonth > 12)
 286         (*pnMonth) -= 12;
 287
 288     /* ...and similarly for the year */
 289     *pnYear = lFactorC - 4715;
 290     if (*pnMonth > 2)
 291         (*pnYear)--;
 292
 293     // Negative year adjustments
 294     if (*pnYear <= 0)
 295         (*pnYear)--;
 296 }
 297
 298 double
 299 Calendar_hijri::getJulianDay(sal_Int32 day, sal_Int32 month, sal_Int32 year)
 300 {
 301     double jy, jm;
 302
 303     if( year == 0 ) {
 304     return -1.0;
 305     }
 306
 307     if( year == 1582 && month == 10 && day > 4 && day < 15 ) {
 308     return -1.0;
 309     }
 310
 311     if( month > 2 ) {
 312     jy = year;
 313     jm = month + 1;
 314     } else {
 315     jy = year - 1;
 316     jm = month + 13;
 317     }
 318
 319     sal_Int32 intgr = (sal_Int32)((sal_Int32)(365.25 * jy) + (sal_Int32)(30.6001 * jm) + day + 1720995 );
 320
 321     //check for switch to Gregorian calendar
 322     double const gregcal = 15 + 31 * ( 10 + 12 * 1582 );
 323
 324     if( day + 31 * (month + 12 * year) >= gregcal ) {
 325         double ja;
 326         ja = (sal_Int32)(0.01 * jy);
 327         intgr += (sal_Int32)(2 - ja + (sal_Int32)(0.25 * ja));
 328     }
 329
 330     return (double) intgr;
 331 }
 332
 333 }
 334
 335 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */