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