class DateTime

# File lib/persian_date.rb, line 8
def to_persian
  
  tmp=0
  gy = self.year - 1600
  gm = self.month - 1
  gd = self.day - 1
  g_day_no = 365*gy + (gy+3)/4 - (gy+99)/100 + (gy+399)/400
  gm.times { |i| g_day_no += GDaysInMonth[i] }
  g_day_no += 1 if gm > 1 && ((gy%4 == 0 && gy%100 != 0) || (gy%400 == 0))
  g_day_no += gd
  
  j_day_no = g_day_no-79
  j_np = j_day_no/12053
  j_day_no %= 12053
  jy = 979 + 33 * j_np + 4*(j_day_no/1461)
  j_day_no %= 1461
  
  if (j_day_no >= 366)
     jy += (j_day_no - 1)/365
     j_day_no = (j_day_no - 1) % 365
  end
  
  11.times do |i|
    if j_day_no >= JDaysInMonth[i]
      j_day_no -= JDaysInMonth[i]
      tmp = i + 1
    else
      tmp = i
      break
    end
  end
  jm = tmp + 1
  jd = j_day_no + 1
  
  [jy, jm, jd]
end