Make code reading BMP files more robust.

[wxWidgets.git] / src / common / datetime.cpp

diff --git a/src/common/datetime.cpp b/src/common/datetime.cpp
index 462347d7d654a3321d4e0a8554dc240d86251588..6ea7a0a37a3a01f0845483387a4333c2a5c3adcf 100644 (file)
--- a/src/common/datetime.cpp
+++ b/src/common/datetime.cpp
@@ -1612,25 +1612,34 @@ wxDateSpan wxDateTime::DiffAsDateSpan(const wxDateTime& dt) const
         inv = -1;
 
     int y = GetYear() - dt.GetYear();
+    int m = GetMonth() - dt.GetMonth();
+    int d = GetDay() - dt.GetDay();
 
     // If month diff is negative, dt is the year before, so decrease year
     // and set month diff to its inverse, e.g. January - December should be 1,
     // not -11.
-    int m = GetMonth() - dt.GetMonth();
-    if ( m * inv < 0 )
+    if ( m * inv < 0 || (m == 0 && d * inv < 0))
     {
         m += inv * MONTHS_IN_YEAR;
         y -= inv;
     }
 
-    // Same logic for days as for months above. Use number of days in month
-    // from the month which end date we're crossing.
-    int d = GetDay() - dt.GetDay();
+    // Same logic for days as for months above.
     if ( d * inv < 0 )
     {
-        d += inv * wxDateTime::GetNumberOfDays(
-            inv > 0 ? dt.GetMonth() : GetMonth(),
-            inv > 0 ? dt.GetYear() : GetMonth());
+        // Use number of days in month from the month which end date we're
+        // crossing. That is month before this for positive diff, and this
+        // month for negative diff.
+        // If we're on january and using previous month, we get december
+        // previous year, but don't care, december has same amount of days
+        // every year.
+        wxDateTime::Month monthfordays = GetMonth();
+        if (inv > 0 && monthfordays == wxDateTime::Jan)
+            monthfordays = wxDateTime::Dec;
+        else if (inv > 0)
+            monthfordays = static_cast<wxDateTime::Month>(monthfordays - 1);
+
+        d += inv * wxDateTime::GetNumberOfDays(monthfordays, GetYear());
         m -= inv;
     }
 
@@ -1912,7 +1921,6 @@ wxDateTime::GetWeekOfYear(wxDateTime::WeekFlags flags, const TimeZone& tz) const
     {
         // adjust the weekdays to non-US style.
         wdYearStart = ConvertWeekDayToMondayBase(wdYearStart);
-        wdTarget = ConvertWeekDayToMondayBase(wdTarget);
 
         // quoting from http://www.cl.cam.ac.uk/~mgk25/iso-time.html:
         //
@@ -1928,22 +1936,24 @@ wxDateTime::GetWeekOfYear(wxDateTime::WeekFlags flags, const TimeZone& tz) const
         //
 
         // if Jan 1 is Thursday or less, it is in the first week of this year
-        if ( wdYearStart < 4 )
-        {
-            // count the number of entire weeks between Jan 1 and this date
-            week = (nDayInYear + wdYearStart + 6 - wdTarget)/7;
+        int dayCountFix = wdYearStart < 4 ? 6 : -1;
 
-            // be careful to check for overflow in the next year
-            if ( week == 53 && tm.mday - wdTarget > 28 )
-                    week = 1;
+        // count the number of week
+        week = (nDayInYear + wdYearStart + dayCountFix) / DAYS_PER_WEEK;
+
+        // check if we happen to be at the last week of previous year:
+        if ( week == 0 )
+        {
+            week = wxDateTime(31, Dec, GetYear() - 1).GetWeekOfYear();
         }
-        else // Jan 1 is in the last week of the previous year
+        else if ( week == 53 )
         {
-            // check if we happen to be at the last week of previous year:
-            if ( tm.mon == Jan && tm.mday < 8 - wdYearStart )
-                week = wxDateTime(31, Dec, GetYear()-1).GetWeekOfYear();
-            else
-                week = (nDayInYear + wdYearStart - 1 - wdTarget)/7;
+            int wdYearEnd = (wdYearStart + 364 + IsLeapYear(GetYear()))
+                                % DAYS_PER_WEEK;
+
+            // Week 53 only if last day of year is Thursday or later.
+            if ( wdYearEnd < 3 )
+                week = 1;
         }
     }