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// Name        :
// Author      : Avi
// Revision    : $Revision: #10 $
//
// Copyright 2009-2020 ECMWF.
// This software is licensed under the terms of the Apache Licence version 2.0
// which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
// In applying this licence, ECMWF does not waive the privileges and immunities
// granted to it by virtue of its status as an intergovernmental organisation
// nor does it submit to any jurisdiction.
//
// Description :
//
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#include "Cal.hpp"

long Cal::julian_to_date(long jdate)
{
   long x,y,d,m,e;
   long day,month,year;

   x = 4 * jdate - 6884477;
   y = (x / 146097) * 100;
   e = x % 146097;
   d = e / 4;

   x = 4 * d + 3;
   y = (x / 1461) + y;
   e = x % 1461;
   d = e / 4 + 1;

   x = 5 * d - 3;
   m = x / 153 + 1;
   e = x % 153;
   d = e / 5 + 1;

   if( m < 11 )
      month = m + 2;
   else
      month = m - 10;


   day = d;
   year = y + m / 11;

   return year * 10000 + month * 100 + day;
}

long Cal::date_to_julian(long ddate)
{
   long  m1,y1,a,b,c,d,j1;
   long month,day,year;

   year = ddate / 10000;
   ddate %= 10000;
   month  = ddate / 100;
   ddate %= 100;
   day = ddate;

   if (month > 2)
   {
      m1 = month - 3;
      y1 = year;
   }
   else
   {
      m1 = month + 9;
      y1 = year - 1;
   }
   a = 146097*(y1/100)/4;
   d = y1 % 100;
   b = 1461*d/4;
   c = (153*m1+2)/5+day+1721119;
   j1 = a+b+c;

   return(j1);
}

// int main(int ac, char** av){ int a=Cal::date_to_julian(20170219) % 7; printf("%d", a); return 0;}
