SCRIPT POUR CONVERTIR UNE DATE GREGORIENNE EN DATE ISO 8601 (N° DE SEMAINE)

<cfscript>
//-------------------------------------------------------------------------------------------------------------->
//-------   Algorithme pour Convertir une Date Gregorienne en Date de semaine ISO 8601   ----------------------->
//-------------------------------------------------------------------------------------------------------------->
	
	//-- 1. Convert input to Y M D
	 Y = Annee;     //(full specification; input 98 = year 0098)
	 M = Mois;      //(1 through 12)
	 D = Jour;      //(1 through 31)
	
	//-- 2. Find if Y is LeapYear IsLeapYear(année)
	
	
	if(IsLeapYear(Y))
	{
	   LeapYear = true;
	}
	else
	{
	   LeapYear = false;
	}
	
	//-- 3. Find if Y-1 is LeapYear
	
	
	if(IsLeapYear(Y-1))
	{
	   LeapYear_1 = true;
	}
	else
	{
	   LeapYear_1 = false;
	}
	
	//-- 4. Find the DayOfYearNumber for Y M D
	
	Mnth = ArrayNew(1);
	Mnth[1] = 0;           
	Mnth[2] = 31;         
	Mnth[3] = 59;         
	Mnth[4] = 90;
	Mnth[5] = 120;
	Mnth[6] = 151;
	Mnth[7] = 181;
	Mnth[8] = 212;
	Mnth[9] = 243;
	Mnth[10] = 273;
	Mnth[11] = 304;
	Mnth[12] = 334;
	
	DayOfYearNumber = D + Mnth[M];
	
	if (LeapYear EQ true AND M GT 2)
	{
	   DayOfYearNumber = DayOfYearNumber + 1;
	}
		 
	//-- 5. Find the Jan1Weekday for Y (Monday=1, Sunday=7)
	
	YY = ( Y - 1 ) MOD 100;
	C = ( Y - 1 ) - YY;
	G = YY + YY / 4;
	Jan1Weekday = 1 + ((((( C / 100 ) MOD 4 ) * 5 ) + G ) MOD 7 );

	//-- 6. Find the Weekday for Y M D
	
	H = DayOfYearNumber + (Jan1Weekday - 1);
	
	Weekday = 1 + (( H - 1 ) MOD 7 );
	
	//-- 7. Find if Y M D falls in YearNumber Y-1, WeekNumber 52 or 53
	
	if ( DayOfYearNumber LE ( 8 - Fix(Jan1Weekday) ) AND Jan1Weekday GE 5 )
	  {
		 YearNumber = Y - 1;
		 if (Fix(Jan1Weekday) EQ 5 OR (Fix(Jan1Weekday) EQ 6 AND LeapYear_1 EQ true))
		 {
			   WeekNumber = 53;
		 }
		 else 
		 {
			   WeekNumber = 52;
		 }
	  }
	  else 
	  {
		 YearNumber = Y;
	  }
		 
	//-- 8. Find if Y M D falls in YearNumber Y+1, WeekNumber 1
	
	if (YearNumber EQ Y)
	{
		if ( LeapYear EQ true )
		{ 
			I = 366;
		}
		else
		{
			I = 365;
		}
		if ( (I - DayOfYearNumber) LT (4 - Weekday) )
		{
			YearNumber = Y + 1;
			WeekNumber = 1;
		}
	}
	
	//-- 9. Find if Y M D falls in YearNumber Y, WeekNumber 1 through 53
	
	if (YearNumber EQ Y)
	{
		 J = DayOfYearNumber + (7 - Weekday) + (Jan1Weekday -1);
		 WeekNumber = J / 7;
		 if (Jan1Weekday GT 4)
		 {
			WeekNumber = WeekNumber - 1;
		 }
	}
	
	Weekday = Fix(Weekday);
	
</cfscript>