resolved fdo#63805 max day of month of the intended month

Since 6619955e72c1c2f29a32e82478d19147c0d7610a Date::GetDaysInMonth()
operates on the normalized value that corresponds to the actual values
set at the Date instance, obtain and set number of days for the intended
month instead of using the rolled-over date.

(cherry picked from commit cd9d1bdf5e3351c929d5b651c009ee17b4d962c4)

Conflicts:
	sc/source/core/data/table4.cxx
	tools/source/datetime/tdate.cxx

Change-Id: Ia6b007675104f8e134b278f216c3bb48b72f061c
Reviewed-on: https://gerrit.libreoffice.org/3939
Reviewed-by: Fridrich Strba <fridrich@documentfoundation.org>
Tested-by: Fridrich Strba <fridrich@documentfoundation.org>

3 files changed, 28 insertions, 12 deletions

diff --git a/sc/source/core/data/table4.cxx b/sc/source/core/data/table4.cxx
index cced07c41b1f..abc885ee471e 100644
--- a/sc/source/core/data/table4.cxx
+++ b/sc/source/core/data/table4.cxx
@@ -1245,8 +1245,7 @@ void ScTable::IncDate(double& rVal, sal_uInt16& nDayOfMonth, double nStep, FillD
                 {
                     aDate.SetMonth((sal_uInt16) nMonth);
                     aDate.SetYear((sal_uInt16) nYear);
-                    if ( nDayOfMonth > 28 )
-                        aDate.SetDay( Min( aDate.GetDaysInMonth(), nDayOfMonth ) );
+                    aDate.SetDay( std::min( Date::GetDaysInMonth( nMonth, nYear), nDayOfMonth ) );
                 }
             }
             break;
diff --git a/tools/inc/tools/date.hxx b/tools/inc/tools/date.hxx
index 71cc65f3b4ad..5d2cb14a3acf 100644
--- a/tools/inc/tools/date.hxx
+++ b/tools/inc/tools/date.hxx
@@ -157,6 +157,13 @@ public:
     TOOLS_DLLPUBLIC friend Date     operator -( const Date& rDate, long nDays );
     TOOLS_DLLPUBLIC friend long     operator -( const Date& rDate1, const Date& rDate2 );
 
+    /** Obtain number of days in a month of a year.
+
+        Internally sanitizes nMonth to values 1 <= nMonth <= 12, does not
+        normalize values.
+     */
+    static sal_uInt16 GetDaysInMonth( sal_uInt16 nMonth, sal_uInt16 nYear );
+
     /// Internally normalizes values.
     static long DateToDays( sal_uInt16 nDay, sal_uInt16 nMonth, sal_uInt16 nYear );
     /// Semantically identical to IsValidDate() member method.
diff --git a/tools/source/datetime/tdate.cxx b/tools/source/datetime/tdate.cxx
index 9d17ec68a3a1..0039d2245081 100644
--- a/tools/source/datetime/tdate.cxx
+++ b/tools/source/datetime/tdate.cxx
@@ -61,8 +61,7 @@ inline sal_Bool ImpIsLeapYear( sal_uInt16 nYear )
 // -----------------------------------------------------------------------
 
 // All callers must have sanitized or normalized month and year values!
-
-inline sal_uInt16 DaysInMonth( sal_uInt16 nMonth, sal_uInt16 nYear )
+inline sal_uInt16 ImplDaysInMonth( sal_uInt16 nMonth, sal_uInt16 nYear )
 {
     if ( nMonth != 2 )
         return aDaysInMonth[nMonth-1];
@@ -75,6 +74,17 @@ inline sal_uInt16 DaysInMonth( sal_uInt16 nMonth, sal_uInt16 nYear )
     }
 }
 
+// static
+sal_uInt16 Date::GetDaysInMonth( sal_uInt16 nMonth, sal_uInt16 nYear )
+{
+    SAL_WARN_IF( nMonth < 1 || 12 < nMonth, "tools", "Date::GetDaysInMonth - nMonth out of bounds " << nMonth);
+    if (nMonth < 1)
+        nMonth = 1;
+    else if (12 < nMonth)
+        nMonth = 12;
+    return ImplDaysInMonth( nMonth, nYear);
+}
+
 // -----------------------------------------------------------------------
 
 long Date::DateToDays( sal_uInt16 nDay, sal_uInt16 nMonth, sal_uInt16 nYear )
@@ -86,7 +96,7 @@ long Date::DateToDays( sal_uInt16 nDay, sal_uInt16 nMonth, sal_uInt16 nYear )
     nDays = ((sal_uIntPtr)nYear-1) * 365;
     nDays += ((nYear-1) / 4) - ((nYear-1) / 100) + ((nYear-1) / 400);
     for( sal_uInt16 i = 1; i < nMonth; i++ )
-        nDays += DaysInMonth(i,nYear);
+        nDays += ImplDaysInMonth(i,nYear);
     nDays += nDay;
     return nDays;
 }
@@ -127,9 +137,9 @@ static void DaysToDate( long nDays,
     while ( bCalc );
 
     rMonth = 1;
-    while ( (sal_uIntPtr)nTempDays > DaysInMonth( rMonth, rYear ) )
+    while ( (sal_uIntPtr)nTempDays > ImplDaysInMonth( rMonth, rYear ) )
     {
-        nTempDays -= DaysInMonth( rMonth, rYear );
+        nTempDays -= ImplDaysInMonth( rMonth, rYear );
         rMonth++;
     }
     rDay = (sal_uInt16)nTempDays;
@@ -213,7 +223,7 @@ sal_uInt16 Date::GetDayOfYear() const
     Normalize( nDay, nMonth, nYear);
 
     for( sal_uInt16 i = 1; i < nMonth; i++ )
-         nDay = nDay + ::DaysInMonth( i, nYear );   // += yields a warning on MSVC, so don't use it
+         nDay = nDay + ::ImplDaysInMonth( i, nYear );   // += yields a warning on MSVC, so don't use it
     return nDay;
 }
 
@@ -318,7 +328,7 @@ sal_uInt16 Date::GetDaysInMonth() const
     sal_uInt16 nYear  = GetYear();
     Normalize( nDay, nMonth, nYear);
 
-    return DaysInMonth( nMonth, nYear );
+    return ImplDaysInMonth( nMonth, nYear );
 }
 
 // -----------------------------------------------------------------------
@@ -339,7 +349,7 @@ sal_Bool Date::IsValidAndGregorian() const
 
     if ( !nMonth || (nMonth > 12) )
         return sal_False;
-    if ( !nDay || (nDay > DaysInMonth( nMonth, nYear )) )
+    if ( !nDay || (nDay > ImplDaysInMonth( nMonth, nYear )) )
         return sal_False;
     else if ( nYear <= 1582 )
     {
@@ -368,7 +378,7 @@ bool Date::IsValidDate( sal_uInt16 nDay, sal_uInt16 nMonth, sal_uInt16 nYear )
 {
     if ( !nMonth || (nMonth > 12) )
         return false;
-    if ( !nDay || (nDay > DaysInMonth( nMonth, nYear )) )
+    if ( !nDay || (nDay > ImplDaysInMonth( nMonth, nYear )) )
         return false;
     return true;
 }
@@ -422,7 +432,7 @@ bool Date::Normalize( sal_uInt16 & rDay, sal_uInt16 & rMonth, sal_uInt16 & rYear
         }
     }
     sal_uInt16 nDays;
-    while (rDay > (nDays = DaysInMonth( rMonth, rYear)))
+    while (rDay > (nDays = ImplDaysInMonth( rMonth, rYear)))
     {
         rDay -= nDays;
         if (rMonth < 12)