Changeset 7458 for trunk/MagicSoft/Mars/mbase/MTime.cc

Timestamp:

12/21/05 20:34:05 (19 years ago)

Author:

tbretz

Message:

*** empty log message ***

File:

• trunk/MagicSoft/Mars/mbase/MTime.cc (modified) (1 diff)

trunk/MagicSoft/Mars/mbase/MTime.cc

@@ -480 +480 @@
 // --------------------------------------------------------------------------
 //
+// Return Mjd of the first day (a monday) which belongs to week 1 of
+// the year give as argument. The returned Mjd might be a date in the
+// year before.
+//
+//  see also MTime::Week()
+//
+Int_t MTime::GetMjdWeek1(Short_t year)
+{
+    MTime t;
+    t.Set(year, 1, 4);
+
+    return (Int_t)t.GetMjd() + t.WeekDay() - 6;
+}
+
+// --------------------------------------------------------------------------
+//
 // Get the week of the year. Valid week values are between 1 and 53.
-// 54 is returned if the day belongs to Week=1 of the next year,
-// 0 if it belongs to the Week=53 and -1 if it belongs to the Week=52
-// of the last year (In this case there is no week 53!)
-//
-Int_t MTime::Week() const
-{
-    static const Int_t kFrSaSo = BIT(kFriday)  | BIT(kSaturday)  | BIT(kSunday);
-    static const Int_t kTuWeTh = BIT(kTuesday) | BIT(kWednesday) | BIT(kThursday);
-
-    MTime t;
-    t.Set(Year(), 1, 1);
-
-    // The weekday of Jan 1st.
-    const Int_t day1st = 1<<t.WeekDay();
-
-    // The number of weeks since the first Monday in the year
-    Int_t week = (DayOfYear()-1 + (t.WeekDay()+6)%7) / 7 + 1;
-
-    // Correct the week number if the year has started with Fr, Sa or So
-    if (day1st & kFrSaSo)
-        week--;
-
-    // If the week number is 53 it might already belong to the next year
-    if (week == 53)
+// If for a january date a week number above 50 is returned the
+// week belongs to the previous year. If for a december data 1 is
+// returned the week already belongs to the next year.
+//
+// The year to which the week belongs is returned in year.
+//
+// Die Kalenderwochen werden für Jahre ab 1976 berechnet, da mit
+// Geltung vom 1. Januar 1976 der Wochenbeginn auf Montag festgelegt
+// wurde. Die erste Woche ist definiert als die Woche, in der
+// mindestens 4 der ersten 7 Januartage fallen (also die Woche, in der
+// der 4. Januar liegt). Beides wurde damals festgelegt in der DIN 1355
+// (1974). Inhaltlich gleich regelt das die Internationale Norm
+// ISO 8601 (1988), die von der Europäischen Union als EN 28601 (1992)
+// übernommen und in Deutschland als DIN EN 28601 (1993) umgesetzt
+// wurde.
+//
+Int_t MTime::Week(Short_t &year) const
+{
+    // Possibilities for Week 1:
+    //
+    //    Mo 4.Jan:   Mo  4. - So 10.    -0   6-6
+    //    Di 4.Jan:   Mo  3. - So  9.    -1   6-5
+    //    Mi 4.Jan:   Mo  2. - So  8.    -2   6-4
+    //    Do 4.Jan:   Mo  1. - So  7.    -3   6-3
+    //    Fr 4.Jan:   Mo 31. - So  6.    -4   6-2
+    //    Sa 4.Jan:   Mo 30. - So  5.    -5   6-1
+    //    So 4.Jan:   Mo 29. - So  4.    -6   6-0
+    //
+    const Int_t mjd2 = GetMjdWeek1(Year()-1);
+    const Int_t mjd0 = GetMjdWeek1(Year());
+    const Int_t mjd3 = GetMjdWeek1(Year()+1);
+
+    // Today
+    const Int_t mjd = (Int_t)GetMjd();
+
+    // Week belongs to last year, return week of last year
+    if (mjd<mjd0)
     {
-        t.Set(Year()+1, 1, 1);
-
-        const Int_t daynext = 1<<t.WeekDay();
-        return daynext&kTuWeTh ? 54 : 53;
+        year = Year()-1;
+        return (mjd-mjd2)/7 + 1;
     }
 
-    // If the week number is 53 it might still belong to the last year
-    if (week == 0)
+    // Check if Week belongs to next year (can only be week 1)
+    if ((mjd3-mjd)/7==1)
     {
-        t.Set(Year()-1, 1, 1);
-
-        const Int_t dayprev = 1<<t.WeekDay();
-        return !(dayprev&kFrSaSo) && (day1st&kFrSaSo) ?  0  :  -1;
+        year = Year()+1;
+        return 1;
     }
 
-    return week;
+    // Return calculated Week
+    year = Year();
+    return (mjd-mjd0)/7 + 1;
 }