typedef unsigned char BYTE;
typedef struct tagDATE11 {
BYTE dtDay;
BYTE dtMonth;
unsigned short dtYear;
} DATE1;
void ConvertGregDateToHijri(DATE1 *, DATE1 *);
void ConvertHijriDateToGreg(DATE1 *, DATE1 *);
// Converts a Hijri M to # of days
static long HM2Days(long m)
{
long mdays[13] = {0,30,59,89,118,148,177,207,236,266,295,325,355};
return (mdays[m-1]);
}
// Returns 1 if Gregorian year is a leap year
static long IsGYLeap(long y)
{
return ((y%4 == 0) && ((y%100 > 0) || (y%400 == 0)));
}
// Converts a Gregorian M to # of days
static long GM2Days(long m)
{
long mdays[13] = {0,31,59,90,120,151,181,212,243,273,304,334,365};
return mdays[m-1];
}
// Returns total # of days for a Gregorian year
static long GY2nDays(long y)
{
y = y - 1;
return (y*365L + y/4 - y/100 + y/400);
}
// Returns 1 if hijri year is a leap year
static long IsHYLeap(long y)
{
long mdays[11]={2,5,7,10,13,15,18,21,24,26,29};
long i;
y %= 30;
for (i=0; i<11; i++)
{
if (y == mdays[i])
return 1;
}
return 0;
}
// Returns total # of days for a Hijri year
static long HY2nDays(long y)
{
long y30, yleft;
long result;
y30 = ((y-1) / 30) * 30;
yleft = y - y30 - 1;
result = ((y30 * 10631L) / 30L) + 227013L;
while (yleft)
result += 354L + IsHYLeap(yleft--);
return result;
}
// Returns Hijri year for a total # of days
static long nDays2HY(long d)
{
long hy = (((d - 227013L) * 30L / 10631L) + 1);
if (d <= HY2nDays(hy))
hy--;
else if (d > HY2nDays(hy+1))
hy++;
return hy;
}
// Returns the Hijri month number corresponding to a certain number of days
static long nDays2HM(long ndays)
{
long i = 1;
long d = (ndays - HY2nDays(nDays2HY(ndays)));
while (d > HM2Days(i))
i++;
return (i - 1);
}
// Converts # of days to a Gregorian year
static long nDays2GY(long days)
{
long d = (days * 400L / 146097L);
if (days > GY2nDays(d+2))
return (d+2);
else if (days > GY2nDays(d+1))
return (d+1);
else
return (d);
}
// Returns 1 if the number of days corresponds to a leap Gregorian year
static long IsnDaysLeap(long days)
{
long y = nDays2GY(days);
return (IsGYLeap(y) && (days - GY2nDays(y) > 59));
}
// Returns the Gregorian month number corresponding to a certain number of days
static long nDays2GM(long ndays)
{
long i = 1;
long d = (ndays - GY2nDays(nDays2GY(ndays)) - IsnDaysLeap(ndays));
while (d > GM2Days(i))
i++;
return (i - 1);
}
// Returns the Hijri day corresponding to a certain number of days
static long nDays2HD(long ndays)
{
return (ndays - HY2nDays(nDays2HY(ndays)) - HM2Days(nDays2HM(ndays)));
}
// Converts a hijri M/D/Y to total # of days
static long HDMY2nDays(long d, long m, long y)
{
return (HY2nDays(y) + HM2Days(m) + d);
}
// Converts a Gregorian M/D/Y to total # of days
static long GDMY2nDays(long d, long m, long y)
{
return ((IsGYLeap(y) && (m > 2)) + GY2nDays(y) + GM2Days(m) + d);
}
// returns the Gregorian day corresponding to a certain number of
static long nDays2GD(long ndays)
{
return (ndays - GDMY2nDays(1, nDays2GM(ndays), nDays2GY(ndays)) + 1);
}
//Convert Gregorian Date to Hijri Date
void ConvertGregDateToHijri(DATE1 *pDGreg, DATE1 *pDHijri)
{
long lDate;
ASSERT( pDHijri && pDGreg );
lDate = GDMY2nDays((long)pDGreg->dtDay, (long)pDGreg->dtMonth, (long)pDGreg->dtYear);
pDHijri->dtMonth = (BYTE)nDays2HM(lDate);
pDHijri->dtYear = (unsigned short)nDays2HY(lDate);
pDHijri->dtDay = (BYTE)nDays2HD(lDate);
}
//Convert Hijri Date to Gregorian
void ConvertHijriDateToGreg(DATE1 *pDHijri, DATE1 *pDGreg)
{
long lDate = 0, x = 0;
ASSERT( pDHijri && pDGreg );
lDate = HDMY2nDays((long)pDHijri->dtDay, (long)pDHijri->dtMonth, (long)pDHijri->dtYear);
pDGreg->dtDay = (BYTE)nDays2GD(lDate);
pDGreg->dtMonth = (BYTE)nDays2GM(lDate);
pDGreg->dtYear = (unsigned short)nDays2GY(lDate);
}
