From f0932941dd2200fa0c5e6afae44d1edeb677355d Mon Sep 17 00:00:00 2001
From: Michael Pfeiffer <michael.w.pfeiffer@gmail.com>
Date: Sat, 30 Aug 2008 16:13:05 +0000
Subject: [PATCH] Simplified initialization of week days for a month.

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@27243 a95241bf-73f2-0310-859d-f6bbb57e9c96
---
 headers/private/shared/DateTime.h |  2 ++
 src/kits/shared/CalendarView.cpp  | 20 +++++---------------
 src/kits/shared/DateTime.cpp      | 27 +++++++++++++++++++++++++++
 3 files changed, 34 insertions(+), 15 deletions(-)

diff --git a/headers/private/shared/DateTime.h b/headers/private/shared/DateTime.h
index 66a1a94e5d..4ff1421ecb 100755
--- a/headers/private/shared/DateTime.h
+++ b/headers/private/shared/DateTime.h
@@ -50,6 +50,8 @@ class BDate {
 
 		static BDate	CurrentDate(time_type type);
 		bool			SetDate(int32 year, int32 month, int32 day);
+		
+		void			AddDays(int32 days);
 
 		int32			Day() const;
 		int32			Year() const;
diff --git a/src/kits/shared/CalendarView.cpp b/src/kits/shared/CalendarView.cpp
index a05af7fb8f..5e1899c20c 100644
--- a/src/kits/shared/CalendarView.cpp
+++ b/src/kits/shared/CalendarView.cpp
@@ -909,7 +909,6 @@ BCalendarView::_SetupDayNumbers()
 	}
 }
 
-
 void
 BCalendarView::_SetupWeekNumbers()
 {
@@ -917,22 +916,13 @@ BCalendarView::_SetupWeekNumbers()
 	if (!date.IsValid())
 		return;
 
-	int32 weekNumber = date.WeekNumber();
-
+	// date on Thursday determines week number (ISO 8601)
+	date.AddDays(4 - date.DayOfWeek());
+	
 	for (int32 row = 0; row < 6; ++row) {
 		fWeekNumbers[row].SetTo("");
-		fWeekNumbers[row] << weekNumber++;
-	}
-
-	if (fMonth == 12) {
-		date.SetDate(fYear, fMonth, 29);
-		weekNumber = date.WeekNumber();
-
-		fWeekNumbers[4].SetTo("");
-		fWeekNumbers[5].SetTo("");
-
-		fWeekNumbers[4] << weekNumber;
-		fWeekNumbers[5] << ((weekNumber != 1) ? 1L : 2L);
+		fWeekNumbers[row] << date.WeekNumber();
+		date.AddDays(7);
 	}
 }
 
diff --git a/src/kits/shared/DateTime.cpp b/src/kits/shared/DateTime.cpp
index 0eb4b4174b..2a03d3d5d1 100755
--- a/src/kits/shared/DateTime.cpp
+++ b/src/kits/shared/DateTime.cpp
@@ -175,6 +175,33 @@ BDate::SetDate(int32 year, int32 month, int32 day)
 }
 
 
+void
+BDate::AddDays(int32 days)
+{
+	days += Day();
+	if (days > 0) {
+		while (days > DaysInMonth()) {
+			days -= DaysInMonth();
+			fMonth ++;
+			if (fMonth == 13) {
+				fMonth = 1;
+				fYear ++;
+			}
+		}
+	} else {
+		while (days <= 0) {
+			fMonth --;
+			if (fMonth == 0) {
+				fMonth = 12;
+				fYear --;
+			}
+			days += DaysInMonth();
+		}
+	}
+	fDay = days;
+}
+
+
 int32
 BDate::Day() const
 {