/**
* Return the number of days in the given Islamic year
* @draft ICU 2.4
*/
int32_t IslamicCalendar::handleGetYearLength(int32_t extendedYear) const {
if (cType == CIVIL || cType == TBLA ||
(cType == UMALQURA && (extendedYear<UMALQURA_YEAR_START || extendedYear>UMALQURA_YEAR_END)) ) {
return 354 + (civilLeapYear(extendedYear) ? 1 : 0);
} else if(cType == ASTRONOMICAL){
int32_t month = 12*(extendedYear-1);
return (trueMonthStart(month + 12) - trueMonthStart(month));
} else {
int len = 0;
for(int i=0; i<12; i++)
len += handleGetMonthLength(extendedYear, i);
return len;
}
}
/**
* Return the day # on which the given month starts. Days are counted
* from the Hijri epoch, origin 0.
*
* @param year The hijri year
* @param year The hijri month, 0-based
*/
int32_t IslamicCalendar::monthStart(int32_t year, int32_t month) const {
if (cType == CIVIL || cType == TBLA) {
return (int32_t)uprv_ceil(29.5*month)
+ (year-1)*354 + (int32_t)ClockMath::floorDivide((3+11*year),30);
} else if(cType==ASTRONOMICAL){
return trueMonthStart(12*(year-1) + month);
} else {
int32_t ms = yearStart(year);
for(int i=0; i< month; i++){
ms+= handleGetMonthLength(year, i);
}
return ms;
}
}
int32_t
GregorianCalendar::monthLength(int32_t month) const
{
int32_t year = internalGet(UCAL_EXTENDED_YEAR);
return handleGetMonthLength(year, month);
}
/**
* Override Calendar to compute several fields specific to the Islamic
* calendar system. These are:
*
* <ul><li>ERA
* <li>YEAR
* <li>MONTH
* <li>DAY_OF_MONTH
* <li>DAY_OF_YEAR
* <li>EXTENDED_YEAR</ul>
*
* The DAY_OF_WEEK and DOW_LOCAL fields are already set when this
* method is called. The getGregorianXxx() methods return Gregorian
* calendar equivalents for the given Julian day.
* @draft ICU 2.4
*/
void IslamicCalendar::handleComputeFields(int32_t julianDay, UErrorCode &status) {
int32_t year, month, dayOfMonth, dayOfYear;
int32_t startDate;
int32_t days = julianDay - CIVIL_EPOC;
if (cType == CIVIL || cType == TBLA) {
if(cType == TBLA) {
days = julianDay - ASTRONOMICAL_EPOC;
}
// Use the civil calendar approximation, which is just arithmetic
year = (int)ClockMath::floorDivide( (double)(30 * days + 10646) , 10631.0 );
month = (int32_t)uprv_ceil((days - 29 - yearStart(year)) / 29.5 );
month = month<11?month:11;
startDate = monthStart(year, month);
} else if(cType == ASTRONOMICAL){
// Guess at the number of elapsed full months since the epoch
int32_t months = (int32_t)uprv_floor((double)days / CalendarAstronomer::SYNODIC_MONTH);
startDate = (int32_t)uprv_floor(months * CalendarAstronomer::SYNODIC_MONTH);
double age = moonAge(internalGetTime(), status);
if (U_FAILURE(status)) {
status = U_MEMORY_ALLOCATION_ERROR;
return;
}
if ( days - startDate >= 25 && age > 0) {
// If we're near the end of the month, assume next month and search backwards
months++;
}
// Find out the last time that the new moon was actually visible at this longitude
// This returns midnight the night that the moon was visible at sunset.
while ((startDate = trueMonthStart(months)) > days) {
// If it was after the date in question, back up a month and try again
months--;
}
year = months / 12 + 1;
month = months % 12;
} else if(cType == UMALQURA) {
int32_t umalquraStartdays = yearStart(UMALQURA_YEAR_START) ;
if( days < umalquraStartdays){
//Use Civil calculation
year = (int)ClockMath::floorDivide( (double)(30 * days + 10646) , 10631.0 );
month = (int32_t)uprv_ceil((days - 29 - yearStart(year)) / 29.5 );
month = month<11?month:11;
startDate = monthStart(year, month);
}else{
int y =UMALQURA_YEAR_START-1, m =0;
long d = 1;
while(d > 0){
y++;
d = days - yearStart(y) +1;
if(d == handleGetYearLength(y)){
m=11;
break;
}else if(d < handleGetYearLength(y) ){
int monthLen = handleGetMonthLength(y, m);
m=0;
while(d > monthLen){
d -= monthLen;
m++;
monthLen = handleGetMonthLength(y, m);
}
break;
}
}
year = y;
month = m;
}
} else { // invalid 'civil'
U_ASSERT(false); // should not get here, out of range
year=month=0;
}
dayOfMonth = (days - monthStart(year, month)) + 1;
// Now figure out the day of the year.
dayOfYear = (days - monthStart(year, 0)) + 1;
internalSet(UCAL_ERA, 0);
internalSet(UCAL_YEAR, year);
internalSet(UCAL_EXTENDED_YEAR, year);
internalSet(UCAL_MONTH, month);
internalSet(UCAL_DAY_OF_MONTH, dayOfMonth);
internalSet(UCAL_DAY_OF_YEAR, dayOfYear);
}
