D语言的两个日期函数

//日期格式为数字 如 20080901
//By zsp007@gmail.com

///验证是否是有效日期
bool date_validate(T)(T date)
{
   static T daysOfMonth[] = [0,31,28,31,30,31,30,31,31,30,31,30,31];

   T monthDay = date % 10000;
   if(monthDay > 1231)
      return false;
   if(monthDay == 229)
   {
      int year = date / 10000;
      if((year % 4) != 0)
          return false;
      return (!(year %100 == 0 && year % 400 != 0));
   }
   int month = monthDay / 100;
   int day = monthDay % 100;
   return (day > 0 && day <= daysOfMonth[month]);
}

///下一天
T tomorrow(T)(T i){
    static T daysOfMonth[] = [0,31,28,31,30,31,30,31,31,30,31,30,31];
    T day=i%100,month=(i/100)%100,year=i/10000;
    
    if(day>=daysOfMonth[month]){
        if(month==12){
            ++year;
            month=1;
            day=1;
        }else if(month==2&&day==28){
            if((year % 4)== 0){
                if(year%100 == 0 && year % 400 != 0){
                    goto add_month;
                }else ++day;
            }else goto add_month;
        }else{
        add_month:
            ++month;
            day=1;
        }
    }else ++day;
    return day+100*month+10000*year;
}