Change nonsense non-const Date* GetNullDate() to const Date&

* first, a non-const Date* may leave the impression that one could change the
NullDate through the pointer, which is only partly successful; luckily no one
did that
* second, there is always a NullDate so checking for nullptr is superfluous
* third, the pointer was dereferenced (maybe after a check) everywhere to
obtain the NullDate, luckily..

Change-Id: I3c3a788ba0336596ac6bde4c96e77a0cdb7a4a95

34 files changed, 96 insertions, 101 deletions

diff --git a/chart2/source/tools/NumberFormatterWrapper.cxx b/chart2/source/tools/NumberFormatterWrapper.cxx
index ead2d47e4cb4..11597d87818a 100644
--- a/chart2/source/tools/NumberFormatterWrapper.cxx
+++ b/chart2/source/tools/NumberFormatterWrapper.cxx
@@ -79,9 +79,7 @@ Date NumberFormatterWrapper::getNullDate() const
     }
     else if( m_pNumberFormatter )
     {
-        Date* pDate = m_pNumberFormatter->GetNullDate();
-        if( pDate )
-            aRet = *pDate;
+        aRet = m_pNumberFormatter->GetNullDate();
     }
     return aRet;
 }
@@ -101,13 +99,10 @@ OUString NumberFormatterWrapper::getFormattedString( sal_Int32 nNumberFormatKey,
     sal_uInt16 nDay = 30,nMonth = 12;
     if ( m_aNullDate.hasValue() )
     {
-        Date* pDate = m_pNumberFormatter->GetNullDate();
-        if ( pDate )
-        {
-            nYear = pDate->GetYear();
-            nMonth = pDate->GetMonth();
-            nDay = pDate->GetDay();
-        } // if ( pDate )
+        const Date& rDate = m_pNumberFormatter->GetNullDate();
+        nYear = rDate.GetYear();
+        nMonth = rDate.GetMonth();
+        nDay = rDate.GetDay();
         util::Date aNewNullDate;
         m_aNullDate >>= aNewNullDate;
         m_pNumberFormatter->ChangeNullDate(aNewNullDate.Day,aNewNullDate.Month,aNewNullDate.Year);
diff --git a/cui/source/options/optupdt.cxx b/cui/source/options/optupdt.cxx
index d229fef9f242..fef9e395d7f9 100644
--- a/cui/source/options/optupdt.cxx
+++ b/cui/source/options/optupdt.cxx
@@ -145,10 +145,10 @@ void SvxOnlineUpdateTabPage::UpdateLastCheckedText()
         LanguageType eUILang = Application::GetSettings().GetUILanguageTag().getLanguageType();
         SvNumberFormatter *pNumberFormatter = new SvNumberFormatter( ::comphelper::getProcessComponentContext(), eUILang );
         Color*      pColor = nullptr;
-        Date*       pNullDate = pNumberFormatter->GetNullDate();
+        const Date& rNullDate = pNumberFormatter->GetNullDate();
         sal_uInt32  nFormat = pNumberFormatter->GetStandardFormat( css::util::NumberFormat::DATE, eUILang );
 
-        pNumberFormatter->GetOutputString( aDate - *pNullDate, nFormat, aDateStr, &pColor );
+        pNumberFormatter->GetOutputString( aDate - rNullDate, nFormat, aDateStr, &pColor );
 
         nFormat = pNumberFormatter->GetStandardFormat( css::util::NumberFormat::TIME, eUILang );
         pNumberFormatter->GetOutputString( aTime.GetTimeInDays(), nFormat, aTimeStr, &pColor );
diff --git a/editeng/source/items/flditem.cxx b/editeng/source/items/flditem.cxx
index cb2c69f3abb1..deff10eb19b6 100644
--- a/editeng/source/items/flditem.cxx
+++ b/editeng/source/items/flditem.cxx
@@ -479,7 +479,7 @@ OUString SvxDateField::GetFormatted( Date& aDate, SvxDateFormat eFormat, SvNumbe
             nFormatKey = rFormatter.GetStandardFormat( css::util::NumberFormat::DATE, eLang );
     }
 
-    double fDiffDate = aDate - *(rFormatter.GetNullDate());
+    double fDiffDate = aDate - rFormatter.GetNullDate();
     OUString aStr;
     Color* pColor = nullptr;
     rFormatter.GetOutputString( fDiffDate, nFormatKey, aStr, &pColor );
diff --git a/extensions/source/propctrlr/standardcontrol.cxx b/extensions/source/propctrlr/standardcontrol.cxx
index dc6e6d492b72..8381a7abad88 100644
--- a/extensions/source/propctrlr/standardcontrol.cxx
+++ b/extensions/source/propctrlr/standardcontrol.cxx
@@ -281,7 +281,7 @@ namespace pcr
             ::DateTime aDateTime( ::DateTime::EMPTY );
             ::utl::typeConvert( aUNODateTime, aDateTime );
 
-            double nValue = aDateTime - ::DateTime( *getTypedControlWindow()->GetFormatter()->GetNullDate() );
+            double nValue = aDateTime - ::DateTime( getTypedControlWindow()->GetFormatter()->GetNullDate() );
             getTypedControlWindow()->SetValue( nValue );
         }
     }
@@ -294,7 +294,7 @@ namespace pcr
         {
             double nValue = getTypedControlWindow()->GetValue();
 
-            ::DateTime aDateTime( *getTypedControlWindow()->GetFormatter()->GetNullDate() );
+            ::DateTime aDateTime( getTypedControlWindow()->GetFormatter()->GetNullDate() );
 
             // add the "days" part
             double nDays = floor( nValue );
diff --git a/include/svl/zforlist.hxx b/include/svl/zforlist.hxx
index f6f338972886..a22e05afb731 100644
--- a/include/svl/zforlist.hxx
+++ b/include/svl/zforlist.hxx
@@ -574,7 +574,7 @@ public:
                               LanguageType eLnge, SvNumberformat* pFormat );
 
     /// Return the reference date
-    Date* GetNullDate();
+    const Date& GetNullDate();
     /// Return the standard decimal precision
     sal_uInt16 GetStandardPrec();
     /// Return whether zero suppression is switched on
diff --git a/sc/source/core/data/conditio.cxx b/sc/source/core/data/conditio.cxx
index 2256947ed7b7..5c5c3125851c 100644
--- a/sc/source/core/data/conditio.cxx
+++ b/sc/source/core/data/conditio.cxx
@@ -1619,11 +1619,11 @@ bool ScCondDateFormatEntry::IsValid( const ScAddress& rPos ) const
 
     const Date& rActDate = *mpCache;
     SvNumberFormatter* pFormatter = mpDoc->GetFormatTable();
-    long nCurrentDate = rActDate - *(pFormatter->GetNullDate());
+    long nCurrentDate = rActDate - pFormatter->GetNullDate();
 
     double nVal = rCell.getValue();
     long nCellDate = (long) ::rtl::math::approxFloor(nVal);
-    Date aCellDate = *(pFormatter->GetNullDate());
+    Date aCellDate = pFormatter->GetNullDate();
     aCellDate += (long) ::rtl::math::approxFloor(nVal);
 
     switch(meType)
diff --git a/sc/source/core/data/dbdocutl.cxx b/sc/source/core/data/dbdocutl.cxx
index 4f8f2bba8f45..0dc3d4f8b014 100644
--- a/sc/source/core/data/dbdocutl.cxx
+++ b/sc/source/core/data/dbdocutl.cxx
@@ -95,7 +95,7 @@ void ScDatabaseDocUtil::PutData( ScDocument* pDoc, SCCOL nCol, SCROW nRow, SCTAB
                         SvNumberFormatter* pFormTable = pDoc->GetFormatTable();
                         nFormatIndex = pFormTable->GetStandardFormat(
                                 css::util::NumberFormat::DATE, ScGlobal::eLnge );
-                        nVal = Date( aDate ) - *pFormTable->GetNullDate();
+                        nVal = Date( aDate ) - pFormTable->GetNullDate();
                     }
                     bValue = true;
                 }
@@ -125,7 +125,7 @@ void ScDatabaseDocUtil::PutData( ScDocument* pDoc, SCCOL nCol, SCROW nRow, SCTAB
 
                     util::DateTime aStamp = xRow->getTimestamp(nRowPos);
                     nVal = ( Date( aStamp.Day, aStamp.Month, aStamp.Year ) -
-                                                *pFormTable->GetNullDate() ) +
+                                                pFormTable->GetNullDate() ) +
                            aStamp.Hours       / static_cast<double>(::tools::Time::hourPerDay)   +
                            aStamp.Minutes     / static_cast<double>(::tools::Time::minutePerDay) +
                            aStamp.Seconds     / static_cast<double>(::tools::Time::secondPerDay) +
diff --git a/sc/source/core/data/dpgroup.cxx b/sc/source/core/data/dpgroup.cxx
index 97c87bff236f..1c2dcaed5164 100644
--- a/sc/source/core/data/dpgroup.cxx
+++ b/sc/source/core/data/dpgroup.cxx
@@ -694,7 +694,7 @@ void ScDPGroupTableData::ModifyFilterCriteria(vector<ScDPFilteredCache::Criterio
                     // grouped by dates.
                     aCri.mpFilter.reset(
                         new ScDPGroupDateFilter(
-                            aMatchValues, *pDoc->GetFormatTable()->GetNullDate(), *pNumInfo));
+                            aMatchValues, pDoc->GetFormatTable()->GetNullDate(), *pNumInfo));
                 }
                 else
                 {
@@ -727,7 +727,7 @@ void ScDPGroupTableData::ModifyFilterCriteria(vector<ScDPFilteredCache::Criterio
                 aCri.mnFieldIndex = nSrcDim;  // use the source dimension, not the group dimension.
                 aCri.mpFilter.reset(
                     new ScDPGroupDateFilter(
-                        aMatchValues, *pDoc->GetFormatTable()->GetNullDate(), *pNumInfo));
+                        aMatchValues, pDoc->GetFormatTable()->GetNullDate(), *pNumInfo));
 
                 aNewCriteria.push_back(aCri);
             }
diff --git a/sc/source/core/data/dpobject.cxx b/sc/source/core/data/dpobject.cxx
index 2ae64ecf64e3..3e07c82eddf1 100644
--- a/sc/source/core/data/dpobject.cxx
+++ b/sc/source/core/data/dpobject.cxx
@@ -3224,7 +3224,7 @@ const ScDPCache* ScDPCollection::DBCaches::getCache(
 
     ::std::unique_ptr<ScDPCache> pCache(new ScDPCache(mpDoc));
     SvNumberFormatter aFormat( comphelper::getProcessComponentContext(), ScGlobal::eLnge);
-    DBConnector aDB(*pCache, xRowSet, *aFormat.GetNullDate());
+    DBConnector aDB(*pCache, xRowSet, aFormat.GetNullDate());
     if (!aDB.isValid())
         return nullptr;
 
@@ -3327,7 +3327,7 @@ void ScDPCollection::DBCaches::updateCache(
     }
 
     SvNumberFormatter aFormat( comphelper::getProcessComponentContext(), ScGlobal::eLnge);
-    DBConnector aDB(rCache, xRowSet, *aFormat.GetNullDate());
+    DBConnector aDB(rCache, xRowSet, aFormat.GetNullDate());
     if (!aDB.isValid())
         return;
 
diff --git a/sc/source/core/data/dputil.cxx b/sc/source/core/data/dputil.cxx
index 440ac8d4e0bc..5bff6bb4d927 100644
--- a/sc/source/core/data/dputil.cxx
+++ b/sc/source/core/data/dputil.cxx
@@ -122,7 +122,7 @@ OUString ScDPUtil::getDateGroupName(
         {
             Date aDate(1, 1, SC_DP_LEAPYEAR);
             aDate += (nValue - 1);            // nValue is 1-based
-            Date aNullDate = *pFormatter->GetNullDate();
+            Date aNullDate = pFormatter->GetNullDate();
             long nDays = aDate - aNullDate;
 
             const sal_uInt32 nFormat = pFormatter->GetFormatIndex(NF_DATE_SYS_DDMMM, ScGlobal::eLnge);
@@ -334,7 +334,7 @@ sal_Int32 ScDPUtil::getDatePartValue(
     }
     else
     {
-        Date aDate = *(pFormatter->GetNullDate());
+        Date aDate = pFormatter->GetNullDate();
         aDate += (long)::rtl::math::approxFloor(fValue);
 
         switch ( nDatePart )
diff --git a/sc/source/core/data/global2.cxx b/sc/source/core/data/global2.cxx
index 1ef86f537b23..ab50f5aae7a4 100644
--- a/sc/source/core/data/global2.cxx
+++ b/sc/source/core/data/global2.cxx
@@ -590,7 +590,7 @@ Label_fallback_to_unambiguous:
                                 else
                                 {
                                     if (pFormatter)
-                                        fValue = aDate - *(pFormatter->GetNullDate());
+                                        fValue = aDate - pFormatter->GetNullDate();
                                     else
                                     {
                                         SAL_WARN("sc.core","ScGlobal::ConvertStringToValue - fixed null date");
diff --git a/sc/source/core/data/table4.cxx b/sc/source/core/data/table4.cxx
index 324eb2201a93..77d51762f3ef 100644
--- a/sc/source/core/data/table4.cxx
+++ b/sc/source/core/data/table4.cxx
@@ -267,7 +267,7 @@ void ScTable::FillAnalyse( SCCOL nCol1, SCROW nRow1, SCCOL nCol2, SCROW nRow2,
             if (nCount > 1)
             {
                 double nVal;
-                Date aNullDate = *pDocument->GetFormatTable()->GetNullDate();
+                Date aNullDate = pDocument->GetFormatTable()->GetNullDate();
                 Date aDate1 = aNullDate;
                 nVal = aFirstCell.mfValue;
                 aDate1 += (long)nVal;
@@ -1077,7 +1077,7 @@ void ScTable::IncDate(double& rVal, sal_uInt16& nDayOfMonth, double nStep, FillD
     const sal_uInt16 nMaxYear = 9956;
 
     long nInc = (long) nStep;       // upper/lower limits ?
-    Date aNullDate = *pDocument->GetFormatTable()->GetNullDate();
+    Date aNullDate = pDocument->GetFormatTable()->GetNullDate();
     Date aDate = aNullDate;
     aDate += (long)rVal;
     switch (eCmd)
diff --git a/sc/source/core/tool/interpr2.cxx b/sc/source/core/tool/interpr2.cxx
index 75a1d6b2debe..2eefbc3093c2 100644
--- a/sc/source/core/tool/interpr2.cxx
+++ b/sc/source/core/tool/interpr2.cxx
@@ -94,7 +94,7 @@ double ScInterpreter::GetDateSerial( sal_Int16 nYear, sal_Int16 nMonth, sal_Int1
     if (!bStrict)
         aDate += nDay - 1;
     if (aDate.IsValidAndGregorian())
-        return (double) (aDate - *(pFormatter->GetNullDate()));
+        return (double) (aDate - pFormatter->GetNullDate());
     else
     {
         SetError(FormulaError::NoValue);
@@ -106,7 +106,7 @@ void ScInterpreter::ScGetActDate()
 {
     nFuncFmtType = css::util::NumberFormat::DATE;
     Date aActDate( Date::SYSTEM );
-    long nDiff = aActDate - *(pFormatter->GetNullDate());
+    long nDiff = aActDate - pFormatter->GetNullDate();
     PushDouble((double) nDiff);
 }
 
@@ -114,7 +114,7 @@ void ScInterpreter::ScGetActTime()
 {
     nFuncFmtType = css::util::NumberFormat::DATETIME;
     Date aActDate( Date::SYSTEM );
-    long nDiff = aActDate - *(pFormatter->GetNullDate());
+    long nDiff = aActDate - pFormatter->GetNullDate();
     tools::Time aActTime( tools::Time::SYSTEM );
     double nTime = aActTime.GetHour()    / static_cast<double>(::tools::Time::hourPerDay)   +
                    aActTime.GetMin()     / static_cast<double>(::tools::Time::minutePerDay) +
@@ -125,21 +125,21 @@ void ScInterpreter::ScGetActTime()
 
 void ScInterpreter::ScGetYear()
 {
-    Date aDate = *(pFormatter->GetNullDate());
+    Date aDate = pFormatter->GetNullDate();
     aDate += (long) GetInt32();
     PushDouble( (double) aDate.GetYear() );
 }
 
 void ScInterpreter::ScGetMonth()
 {
-    Date aDate = *(pFormatter->GetNullDate());
+    Date aDate = pFormatter->GetNullDate();
     aDate += (long) GetInt32();
     PushDouble( (double) aDate.GetMonth() );
 }
 
 void ScInterpreter::ScGetDay()
 {
-    Date aDate = *(pFormatter->GetNullDate());
+    Date aDate = pFormatter->GetNullDate();
     aDate += (long) GetInt32();
     PushDouble((double) aDate.GetDay());
 }
@@ -199,7 +199,7 @@ void ScInterpreter::ScGetDayOfWeek()
         else
             nFlag = 1;
 
-        Date aDate = *(pFormatter->GetNullDate());
+        Date aDate = pFormatter->GetNullDate();
         aDate += (long) GetInt32();
         int nVal = (int) aDate.GetDayOfWeek();  // MONDAY = 0
         switch (nFlag)
@@ -241,7 +241,7 @@ void ScInterpreter::ScWeeknumOOo()
     {
         sal_Int16 nFlag = GetInt16();
 
-        Date aDate = *(pFormatter->GetNullDate());
+        Date aDate = pFormatter->GetNullDate();
         aDate += (long) GetInt32();
         PushInt( (int) aDate.GetWeekOfYear( nFlag == 1 ? SUNDAY : MONDAY ));
     }
@@ -258,7 +258,7 @@ void ScInterpreter::ScGetWeekOfYear()
         else
             nFlag = GetInt16();
 
-        Date aDate = *(pFormatter->GetNullDate());
+        Date aDate = pFormatter->GetNullDate();
         aDate += (long) GetInt32();
 
         sal_Int32 nMinimumNumberOfDaysInWeek;
@@ -301,7 +301,7 @@ void ScInterpreter::ScGetIsoWeekOfYear()
 {
     if ( MustHaveParamCount( GetByte(), 1 ) )
     {
-        Date aDate = *(pFormatter->GetNullDate());
+        Date aDate = pFormatter->GetNullDate();
         aDate += (long) GetInt32();
         PushInt( (int) aDate.GetWeekOfYear() );
     }
@@ -513,7 +513,7 @@ void ScInterpreter::ScNetWorkdays( bool bOOXML_Version )
     {
         vector<double> nSortArray;
         bool bWeekendMask[ 7 ];
-        Date aNullDate = *( pFormatter->GetNullDate() );
+        Date aNullDate = pFormatter->GetNullDate();
         sal_uInt32 nNullDate = Date::DateToDays( aNullDate.GetDay(), aNullDate.GetMonth(), aNullDate.GetYear() );
         FormulaError nErr;
         if ( bOOXML_Version )
@@ -574,7 +574,7 @@ void ScInterpreter::ScWorkday_MS()
         nFuncFmtType = css::util::NumberFormat::DATE;
         vector<double> nSortArray;
         bool bWeekendMask[ 7 ];
-        Date aNullDate = *( pFormatter->GetNullDate() );
+        Date aNullDate = pFormatter->GetNullDate();
         sal_uInt32 nNullDate = Date::DateToDays( aNullDate.GetDay(), aNullDate.GetMonth(), aNullDate.GetYear() );
         FormulaError nErr = GetWeekendAndHolidayMasks_MS( nParamCount, nNullDate,
                             nSortArray, bWeekendMask, true );
@@ -736,9 +736,9 @@ void ScInterpreter::ScGetDiffDate360()
             }
             else
                 fSign = 1.0;
-            Date aDate1 = *(pFormatter->GetNullDate());
+            Date aDate1 = pFormatter->GetNullDate();
             aDate1 += (long) ::rtl::math::approxFloor(nDate1);
-            Date aDate2 = *(pFormatter->GetNullDate());
+            Date aDate2 = pFormatter->GetNullDate();
             aDate2 += (long) ::rtl::math::approxFloor(nDate2);
             if (aDate1.GetDay() == 31)
                 aDate1 -= (sal_uLong) 1;
@@ -810,12 +810,12 @@ void ScInterpreter::ScGetDateDif()
         // split dates in day, month, year for use with formats other than "d"
         sal_uInt16 d1, m1, d2, m2;
         sal_Int16 y1, y2;
-        Date aDate1( *( pFormatter->GetNullDate()));
+        Date aDate1( pFormatter->GetNullDate());
         aDate1 += nDate1;
         y1 = aDate1.GetYear();
         m1 = aDate1.GetMonth();
         d1 = aDate1.GetDay();
-        Date aDate2( *( pFormatter->GetNullDate()));
+        Date aDate2( pFormatter->GetNullDate());
         aDate2 += nDate2;
         y2 = aDate2.GetYear();
         m2 = aDate2.GetMonth();
diff --git a/sc/source/core/tool/interpr8.cxx b/sc/source/core/tool/interpr8.cxx
index b661a220ec27..96da08bb6e58 100644
--- a/sc/source/core/tool/interpr8.cxx
+++ b/sc/source/core/tool/interpr8.cxx
@@ -192,7 +192,7 @@ bool ScETSForecastCalculation::PreprocessDataRange( const ScMatrixRef& rMatX, co
     // Method: assume there is an month interval and verify.
     // If month interval is used, replace maRange.X with month values
     // for ease of calculations.
-    Date aNullDate = *( mpFormatter->GetNullDate() );
+    Date aNullDate = mpFormatter->GetNullDate();
     Date aDate = aNullDate + static_cast< long >( maRange[ 0 ].X );
     mnMonthDay = aDate.GetDay();
     for ( SCSIZE i = 1; i < mnCount && mnMonthDay; i++ )
@@ -812,7 +812,7 @@ void ScETSForecastCalculation::refill()
 
 double ScETSForecastCalculation::convertXtoMonths( double x )
 {
-    Date aNullDate = *( mpFormatter->GetNullDate() );
+    Date aNullDate = mpFormatter->GetNullDate();
     Date aDate = aNullDate + static_cast< long >( x );
     int nYear = aDate.GetYear();
     int nMonth = aDate.GetMonth();
diff --git a/sc/source/filter/excel/excrecds.cxx b/sc/source/filter/excel/excrecds.cxx
index fd0ce5977ddb..9b2c67cbbb85 100644
--- a/sc/source/filter/excel/excrecds.cxx
+++ b/sc/source/filter/excel/excrecds.cxx
@@ -286,9 +286,9 @@ const sal_uInt8* ExcDummy_041::GetData() const
 
 Exc1904::Exc1904( ScDocument& rDoc )
 {
-    Date* pDate = rDoc.GetFormatTable()->GetNullDate();
-    bVal = pDate && (*pDate == Date( 1, 1, 1904 ));
-    bDateCompatibility = pDate && !( *pDate == Date( 30, 12, 1899 ));
+    const Date& rDate = rDoc.GetFormatTable()->GetNullDate();
+    bVal = (rDate == Date( 1, 1, 1904 ));
+    bDateCompatibility = !(rDate == Date( 30, 12, 1899 ));
 }
 
 sal_uInt16 Exc1904::GetNum() const
diff --git a/sc/source/filter/excel/xlroot.cxx b/sc/source/filter/excel/xlroot.cxx
index 262f40b409ba..72b1450a5084 100644
--- a/sc/source/filter/excel/xlroot.cxx
+++ b/sc/source/filter/excel/xlroot.cxx
@@ -316,7 +316,7 @@ SvNumberFormatter& XclRoot::GetFormatter() const
 
 DateTime XclRoot::GetNullDate() const
 {
-    return *GetFormatter().GetNullDate();
+    return GetFormatter().GetNullDate();
 }
 
 sal_uInt16 XclRoot::GetBaseYear() const
diff --git a/sc/source/filter/orcus/interface.cxx b/sc/source/filter/orcus/interface.cxx
index 35e9ffacfafa..c56f1c67cb80 100644
--- a/sc/source/filter/orcus/interface.cxx
+++ b/sc/source/filter/orcus/interface.cxx
@@ -529,7 +529,7 @@ void ScOrcusSheet::set_date_time(
     sal_uInt32 nSec = floor(second);
     sal_uInt32 nNanoSec = (second - nSec) * ::tools::Time::nanoSecPerSec;
     tools::Time aTime(hour, minute, nSec, nNanoSec);
-    Date aNullDate(*pFormatter->GetNullDate());
+    Date aNullDate(pFormatter->GetNullDate());
     long nDateDiff = aDate - aNullDate;
 
     double fTime =
diff --git a/sc/source/ui/cctrl/checklistmenu.cxx b/sc/source/ui/cctrl/checklistmenu.cxx
index e877e38097c0..86f8a2d446cf 100644
--- a/sc/source/ui/cctrl/checklistmenu.cxx
+++ b/sc/source/ui/cctrl/checklistmenu.cxx
@@ -1434,7 +1434,7 @@ void ScCheckListMenuWindow::addDateMember(const OUString& rsName, double nVal, b
     SvNumberFormatter* pFormatter = pDoc->GetFormatTable();
 
     // Convert the numeric date value to a date object.
-    Date aDate = *(pFormatter->GetNullDate());
+    Date aDate = pFormatter->GetNullDate();
     aDate += static_cast<long>(rtl::math::approxFloor(nVal));
 
     sal_Int16 nYear = aDate.GetYear();
diff --git a/sc/source/ui/docshell/docsh8.cxx b/sc/source/ui/docshell/docsh8.cxx
index 5a676d24d029..2cdcbbfe96c6 100644
--- a/sc/source/ui/docshell/docsh8.cxx
+++ b/sc/source/ui/docshell/docsh8.cxx
@@ -966,7 +966,7 @@ ErrCode ScDocShell::DBaseExport( const OUString& rFullFileName, rtl_TextEncoding
                             }
                             else
                             {
-                                Date aDate = *(pNumFmt->GetNullDate());     // tools date
+                                Date aDate = pNumFmt->GetNullDate();        // tools date
                                 aDate += (long)fVal;                        //! approxfloor?
                                 xRowUpdate->updateDate( nCol+1, aDate.GetUNODate() );
                             }
diff --git a/sc/source/ui/docshell/impex.cxx b/sc/source/ui/docshell/impex.cxx
index 76f6ed8a9803..f992c18061c0 100644
--- a/sc/source/ui/docshell/impex.cxx
+++ b/sc/source/ui/docshell/impex.cxx
@@ -1162,7 +1162,7 @@ static bool lcl_PutString(
                 pCalendar->setValue( i18n::CalendarFieldIndex::MILLISECOND, nMilli );
                 if ( pCalendar->isValid() )
                 {
-                    double fDiff = DateTime(*pDocFormatter->GetNullDate()) -
+                    double fDiff = DateTime(pDocFormatter->GetNullDate()) -
                         pCalendar->getEpochStart();
                     // #i14974# must use getLocalDateTime to get the same
                     // date values as set above
diff --git a/sc/source/ui/view/cellsh1.cxx b/sc/source/ui/view/cellsh1.cxx
index ff173fda39fe..99e6ba02476a 100644
--- a/sc/source/ui/view/cellsh1.cxx
+++ b/sc/source/ui/view/cellsh1.cxx
@@ -689,7 +689,7 @@ void ScCellShell::ExecuteEdit( SfxRequest& rReq )
                         }
                         if(eFillCmd==FILL_DATE)
                         {
-                            Date aNullDate = *pDoc->GetFormatTable()->GetNullDate();
+                            Date aNullDate = pDoc->GetFormatTable()->GetNullDate();
                             Date aStartDate = aNullDate;
                             aStartDate+= (long)fStartVal;
                             Date aEndDate = aNullDate;
@@ -1119,7 +1119,7 @@ void ScCellShell::ExecuteEdit( SfxRequest& rReq )
                     {
                         ScAbstractDialogFactory* pFact = ScAbstractDialogFactory::Create();
                         OSL_ENSURE( pFact, "ScAbstractFactory create fail!" );
-                        Date aNullDate( *GetViewData()->GetDocument()->GetFormatTable()->GetNullDate() );
+                        Date aNullDate( GetViewData()->GetDocument()->GetFormatTable()->GetNullDate() );
                         ScopedVclPtr<AbstractScDPDateGroupDlg> pDlg( pFact->CreateScDPDateGroupDlg(
                             pTabViewShell->GetDialogParent(),
                             aNumInfo, nParts, aNullDate ) );
diff --git a/sc/source/ui/view/viewfun6.cxx b/sc/source/ui/view/viewfun6.cxx
index 97ca1bdb4f23..9816afda8d20 100644
--- a/sc/source/ui/view/viewfun6.cxx
+++ b/sc/source/ui/view/viewfun6.cxx
@@ -280,7 +280,7 @@ void ScViewFunc::InsertCurrentTime(short nReqFmt, const OUString& rUndoStr)
             case css::util::NumberFormat::DATE:
                 {
                     Date aActDate( Date::SYSTEM );
-                    fVal = aActDate - *pFormatter->GetNullDate();
+                    fVal = aActDate - pFormatter->GetNullDate();
                     if (nCurNumFormatType == css::util::NumberFormat::DATE)
                         nFormat = nCurNumFormat;
                 }
@@ -300,7 +300,7 @@ void ScViewFunc::InsertCurrentTime(short nReqFmt, const OUString& rUndoStr)
             case css::util::NumberFormat::DATETIME:
                 {
                     DateTime aActDateTime( DateTime::SYSTEM );
-                    fVal = aActDateTime - DateTime( *pFormatter->GetNullDate());
+                    fVal = aActDateTime - DateTime( pFormatter->GetNullDate());
                     if (nCurNumFormatType == css::util::NumberFormat::DATETIME)
                         nFormat = nCurNumFormat;
                 }
@@ -353,7 +353,7 @@ void ScViewFunc::InsertCurrentTime(short nReqFmt, const OUString& rUndoStr)
                             // date, which otherwise would only be possible by
                             // applying a date format.
                             double fDate = rtl::math::approxFloor( fCell);
-                            if (fDate == (Date( Date::SYSTEM) - *pFormatter->GetNullDate()))
+                            if (fDate == (Date( Date::SYSTEM) - pFormatter->GetNullDate()))
                                 bForceReqFmt = true;
                         }
                         break;
@@ -379,7 +379,7 @@ void ScViewFunc::InsertCurrentTime(short nReqFmt, const OUString& rUndoStr)
                             // zero and date is current date, else force time only.
                             double fDate = rtl::math::approxFloor( fCell);
                             double fTime = fCell - fDate;
-                            if (fTime == 0.0 && fDate == (Date( Date::SYSTEM) - *pFormatter->GetNullDate()))
+                            if (fTime == 0.0 && fDate == (Date( Date::SYSTEM) - pFormatter->GetNullDate()))
                                 nReqFmt = css::util::NumberFormat::DATETIME;
                             else
                                 bForceReqFmt = true;
@@ -400,7 +400,7 @@ void ScViewFunc::InsertCurrentTime(short nReqFmt, const OUString& rUndoStr)
             case css::util::NumberFormat::DATE:
                 {
                     Date aActDate( Date::SYSTEM );
-                    fVal = aActDate - *pFormatter->GetNullDate();
+                    fVal = aActDate - pFormatter->GetNullDate();
                 }
                 break;
             case css::util::NumberFormat::TIME:
@@ -423,7 +423,7 @@ void ScViewFunc::InsertCurrentTime(short nReqFmt, const OUString& rUndoStr)
                         {
                             double fTime = fCell - rtl::math::approxFloor( fCell);
                             Date aActDate( Date::SYSTEM );
-                            fVal = (aActDate - *pFormatter->GetNullDate()) + fTime;
+                            fVal = (aActDate - pFormatter->GetNullDate()) + fTime;
                         }
                         break;
                     default:
@@ -432,7 +432,7 @@ void ScViewFunc::InsertCurrentTime(short nReqFmt, const OUString& rUndoStr)
                             // Converting the null date to DateTime forces the
                             // correct operator-() to be used, resulting in a
                             // fractional date+time instead of only date value.
-                            fVal = aActDateTime - DateTime( *pFormatter->GetNullDate());
+                            fVal = aActDateTime - DateTime( pFormatter->GetNullDate());
                         }
                 }
                 break;
diff --git a/svl/source/numbers/numfmuno.cxx b/svl/source/numbers/numfmuno.cxx
index bef4075994e1..9c014f06ccac 100644
--- a/svl/source/numbers/numfmuno.cxx
+++ b/svl/source/numbers/numfmuno.cxx
@@ -927,11 +927,8 @@ uno::Any SAL_CALL SvNumberFormatSettingsObj::getPropertyValue( const OUString& a
         }
         else if (aPropertyName == PROPERTYNAME_NULLDATE)
         {
-            Date* pDate = pFormatter->GetNullDate();
-            if (pDate)
-            {
-                aRet <<= pDate->GetUNODate();
-            }
+            const Date& rDate = pFormatter->GetNullDate();
+            aRet <<= rDate.GetUNODate();
         }
         else if (aPropertyName == PROPERTYNAME_STDDEC)
             aRet <<= (sal_Int16)( pFormatter->GetStandardPrec() );
diff --git a/svl/source/numbers/zforlist.cxx b/svl/source/numbers/zforlist.cxx
index 1acc79778e4a..2f3059ec4378 100644
--- a/svl/source/numbers/zforlist.cxx
+++ b/svl/source/numbers/zforlist.cxx
@@ -395,7 +395,7 @@ void SvNumberFormatter::ChangeNullDate(sal_uInt16 nDay,
     pStringScanner->ChangeNullDate(nDay, nMonth, nYear);
 }
 
-Date* SvNumberFormatter::GetNullDate()
+const Date& SvNumberFormatter::GetNullDate()
 {
     return pFormatScanner->GetNullDate();
 }
diff --git a/svl/source/numbers/zformat.cxx b/svl/source/numbers/zformat.cxx
index a736c16518dc..224190550edd 100644
--- a/svl/source/numbers/zformat.cxx
+++ b/svl/source/numbers/zformat.cxx
@@ -2997,7 +2997,7 @@ bool SvNumberformat::ImpGetTimeOutput(double fNumber,
         case NF_KEY_AMPM:               // AM/PM
             if ( !bCalendarSet )
             {
-                double fDiff = DateTime(*(rScan.GetNullDate())) - GetCal().getEpochStart();
+                double fDiff = DateTime(rScan.GetNullDate()) - GetCal().getEpochStart();
                 fDiff += fNumberOrig;
                 GetCal().setLocalDateTime( fDiff );
                 bCalendarSet = true;
@@ -3454,7 +3454,7 @@ bool SvNumberformat::ImpGetDateOutput(double fNumber,
     bool bRes = false;
 
     CalendarWrapper& rCal = GetCal();
-    double fDiff = DateTime(*(rScan.GetNullDate())) - rCal.getEpochStart();
+    double fDiff = DateTime(rScan.GetNullDate()) - rCal.getEpochStart();
     fNumber += fDiff;
     rCal.setLocalDateTime( fNumber );
     int nUseMonthCase = 0; // Not decided yet
@@ -3661,7 +3661,7 @@ bool SvNumberformat::ImpGetDateTimeOutput(double fNumber,
     bool bRes = false;
 
     CalendarWrapper& rCal = GetCal();
-    double fDiff = DateTime(*(rScan.GetNullDate())) - rCal.getEpochStart();
+    double fDiff = DateTime(rScan.GetNullDate()) - rCal.getEpochStart();
     fNumber += fDiff;
 
     const ImpSvNumberformatInfo& rInfo = NumFor[nIx].Info();
diff --git a/svl/source/numbers/zforscan.cxx b/svl/source/numbers/zforscan.cxx
index 25014fa7e0f5..13c0362e873f 100644
--- a/svl/source/numbers/zforscan.cxx
+++ b/svl/source/numbers/zforscan.cxx
@@ -40,7 +40,8 @@ const sal_Unicode cNoBreakSpace = 0xA0;
 const sal_Unicode cNarrowNoBreakSpace = 0x202F;
 
 ImpSvNumberformatScan::ImpSvNumberformatScan( SvNumberFormatter* pFormatterP )
-    : eNewLnge(LANGUAGE_DONTKNOW)
+    : maNullDate( 30, 12, 1899)
+    , eNewLnge(LANGUAGE_DONTKNOW)
     , eTmpLnge(LANGUAGE_DONTKNOW)
     , nCurrPos(-1)
 {
@@ -77,7 +78,6 @@ ImpSvNumberformatScan::ImpSvNumberformatScan( SvNumberFormatter* pFormatterP )
     StandardColor[8]  =  Color(COL_YELLOW);
     StandardColor[9]  =  Color(COL_WHITE);
 
-    pNullDate = new Date(30,12,1899);
     nStandardPrec = 2;
 
     sErrStr =  "###";
@@ -86,7 +86,6 @@ ImpSvNumberformatScan::ImpSvNumberformatScan( SvNumberFormatter* pFormatterP )
 
 ImpSvNumberformatScan::~ImpSvNumberformatScan()
 {
-    delete pNullDate;
     Reset();
 }
 
@@ -429,10 +428,14 @@ void ImpSvNumberformatScan::SetDependentKeywords()
 
 void ImpSvNumberformatScan::ChangeNullDate(sal_uInt16 nDay, sal_uInt16 nMonth, sal_Int16 nYear)
 {
-    if ( pNullDate )
-        *pNullDate = Date(nDay, nMonth, nYear);
-    else
-        pNullDate = new Date(nDay, nMonth, nYear);
+    maNullDate = Date(nDay, nMonth, nYear);
+    if (!maNullDate.IsValidDate())
+    {
+        maNullDate.Normalize();
+        SAL_WARN("svl.numbers","ImpSvNumberformatScan::ChangeNullDate - not valid"
+                " d: " << nDay << " m: " << nMonth << " y: " << nYear << " normalized to"
+                " d: " << maNullDate.GetDay() << " m: " << maNullDate.GetMonth() << " y: " << maNullDate.GetYear());
+    }
 }
 
 void ImpSvNumberformatScan::ChangeStandardPrec(sal_uInt16 nPrec)
diff --git a/svl/source/numbers/zforscan.hxx b/svl/source/numbers/zforscan.hxx
index 13d5b1a67177..5aaee72f870f 100644
--- a/svl/source/numbers/zforscan.hxx
+++ b/svl/source/numbers/zforscan.hxx
@@ -80,7 +80,7 @@ public:
     const OUString& GetBooleanString() const  { return GetKeywords()[NF_KEY_BOOLEAN]; }
     const OUString& GetErrorString() const    { return sErrStr; }
 
-    Date* GetNullDate() const                   { return pNullDate; }
+    const Date& GetNullDate() const           { return maNullDate; }
     const OUString& GetStandardName() const
         {
             if ( bKeywordsNeedInit )
@@ -150,7 +150,7 @@ public:
 private: // Private section
     NfKeywordTable sKeyword;                    // Syntax keywords
     Color StandardColor[NF_MAX_DEFAULT_COLORS]; // Standard color array
-    Date* pNullDate;                            // 30Dec1899
+    Date maNullDate;                            // 30Dec1899
     OUString sNameStandardFormat;               // "Standard"
     sal_uInt16 nStandardPrec;                   // Default Precision for Standardformat
     SvNumberFormatter* pFormatter;              // Pointer to the FormatList
diff --git a/sw/source/core/bastyp/calc.cxx b/sw/source/core/bastyp/calc.cxx
index 80f10a9821f0..2fd656296bf4 100644
--- a/sw/source/core/bastyp/calc.cxx
+++ b/sw/source/core/bastyp/calc.cxx
@@ -220,9 +220,9 @@ static double lcl_ConvertToDateValue( SwDoc& rDoc, sal_Int32 nDate )
     SvNumberFormatter* pFormatter = rDoc.GetNumberFormatter();
     if( pFormatter )
     {
-        Date* pNull = pFormatter->GetNullDate();
+        const Date& rNull = pFormatter->GetNullDate();
         Date aDate( nDate >> 24, (nDate& 0x00FF0000) >> 16, nDate& 0x0000FFFF );
-        nRet = aDate - *pNull;
+        nRet = aDate - rNull;
     }
     return nRet;
 }
diff --git a/sw/source/core/fields/dbfld.cxx b/sw/source/core/fields/dbfld.cxx
index 1790ae8eabe3..0df616a710cc 100644
--- a/sw/source/core/fields/dbfld.cxx
+++ b/sw/source/core/fields/dbfld.cxx
@@ -275,8 +275,8 @@ bool SwDBField::FormatValue( SvNumberFormatter* pDocFormatter, OUString &aString
             DataType::TIMESTAMP  == nColumnType )
         {
             Date aStandard( 1, 1, 1900 );
-            if( *pDocFormatter->GetNullDate() != aStandard )
-                aNumber += (aStandard - *pDocFormatter->GetNullDate());
+            if( pDocFormatter->GetNullDate() != aStandard )
+                aNumber += (aStandard - pDocFormatter->GetNullDate());
         }
         bValidValue = true;
         if( pField )
diff --git a/sw/source/core/fields/docufld.cxx b/sw/source/core/fields/docufld.cxx
index 692fb7ee723d..aae7cacee181 100644
--- a/sw/source/core/fields/docufld.cxx
+++ b/sw/source/core/fields/docufld.cxx
@@ -1070,15 +1070,15 @@ OUString SwDocInfoField::Expand() const
                     if( aAny >>= aDate)
                     {
                         SvNumberFormatter* pFormatter = pDocShell->GetDoc()->GetNumberFormatter();
-                        Date* pNullDate = pFormatter->GetNullDate();
-                        sVal = ExpandValue( lcl_DateToDouble<util::Date>( aDate, *pNullDate ), GetFormat(), GetLanguage());
+                        const Date& rNullDate = pFormatter->GetNullDate();
+                        sVal = ExpandValue( lcl_DateToDouble<util::Date>( aDate, rNullDate ), GetFormat(), GetLanguage());
                     }
                     else if( aAny >>= aDateTime )
                     {
                         double fDateTime = lcl_TimeToDouble<util::DateTime>( aDateTime );
                         SvNumberFormatter* pFormatter = pDocShell->GetDoc()->GetNumberFormatter();
-                        Date* pNullDate = pFormatter->GetNullDate();
-                        fDateTime += lcl_DateToDouble<util::DateTime>( aDateTime, *pNullDate );
+                        const Date& rNullDate = pFormatter->GetNullDate();
+                        fDateTime += lcl_DateToDouble<util::DateTime>( aDateTime, rNullDate );
                         sVal = ExpandValue( fDateTime, GetFormat(), GetLanguage());
                     }
                     else if( aAny >>= aDuration )
diff --git a/sw/source/core/fields/flddat.cxx b/sw/source/core/fields/flddat.cxx
index 56c532c66b8c..5ae5da51a9c3 100644
--- a/sw/source/core/fields/flddat.cxx
+++ b/sw/source/core/fields/flddat.cxx
@@ -121,9 +121,9 @@ void SwDateTimeField::SetDateTime(const DateTime& rDT)
 double SwDateTimeField::GetDateTime(SwDoc* pDoc, const DateTime& rDT)
 {
     SvNumberFormatter* pFormatter = pDoc->GetNumberFormatter();
-    Date* pNullDate = pFormatter->GetNullDate();
+    const Date& rNullDate = pFormatter->GetNullDate();
 
-    double fResult = rDT - DateTime(*pNullDate);
+    double fResult = rDT - DateTime(rNullDate);
 
     return fResult;
 }
@@ -139,11 +139,11 @@ double SwDateTimeField::GetValue() const
 Date SwDateTimeField::GetDate() const
 {
     SvNumberFormatter* pFormatter = GetDoc()->GetNumberFormatter();
-    Date* pNullDate = pFormatter->GetNullDate();
+    const Date& rNullDate = pFormatter->GetNullDate();
 
     long nVal = static_cast<long>( GetValue() );
 
-    Date aDate = *pNullDate + nVal;
+    Date aDate = rNullDate + nVal;
 
     return aDate;
 }
diff --git a/sw/source/core/text/EnhancedPDFExportHelper.cxx b/sw/source/core/text/EnhancedPDFExportHelper.cxx
index bf26e0d4900b..3f0ddffcacd5 100644
--- a/sw/source/core/text/EnhancedPDFExportHelper.cxx
+++ b/sw/source/core/text/EnhancedPDFExportHelper.cxx
@@ -1595,7 +1595,7 @@ void SwEnhancedPDFExportHelper::EnhancedPDFExport()
                             const SwPostItField* pField = static_cast<SwPostItField*>(pFirst->GetField());
                             SvNumberFormatter* pNumFormatter = pDoc->GetNumberFormatter();
                             const Date aDateDiff( pField->GetDate() -
-                                                 *pNumFormatter->GetNullDate() );
+                                                 pNumFormatter->GetNullDate() );
                             const sal_uLong nFormat =
                                 pNumFormatter->GetStandardFormat( css::util::NumberFormat::DATE, pField->GetLanguage() );
                             OUString sDate;
diff --git a/sw/source/ui/dbui/dbinsdlg.cxx b/sw/source/ui/dbui/dbinsdlg.cxx
index 97abb559b731..207da08081b4 100644
--- a/sw/source/ui/dbui/dbinsdlg.cxx
+++ b/sw/source/ui/dbui/dbinsdlg.cxx
@@ -1136,8 +1136,8 @@ void SwInsertDBColAutoPilot::DataToDoc( const Sequence<Any>& rSelection,
                                 if(rNumFormatr.GetType(aNumFormat.GetValue()) & css::util::NumberFormat::DATE)
                                 {
                                     ::Date aStandard(1,1,1900);
-                                    if (*rNumFormatr.GetNullDate() != aStandard)
-                                        fVal += (aStandard - *rNumFormatr.GetNullDate());
+                                    if (rNumFormatr.GetNullDate() != aStandard)
+                                        fVal += (aStandard - rNumFormatr.GetNullDate());
                                 }
                                 aTableSet.Put( SwTableBoxValue( fVal ));
                             }
@@ -1370,8 +1370,8 @@ void SwInsertDBColAutoPilot::DataToDoc( const Sequence<Any>& rSelection,
                                 if(rNumFormatr.GetType(pDBCol->nFormat) & css::util::NumberFormat::DATE)
                                 {
                                     ::Date aStandard(1,1,1900);
-                                    if (*rNumFormatr.GetNullDate() != aStandard)
-                                        nValue += (aStandard - *rNumFormatr.GetNullDate());
+                                    if (rNumFormatr.GetNullDate() != aStandard)
+                                        nValue += (aStandard - rNumFormatr.GetNullDate());
                                 }
                                 rNumFormatr.GetOutputString( nValue,
                                             pDBCol->nFormat,
diff --git a/uui/source/iahndl-ssl.cxx b/uui/source/iahndl-ssl.cxx
index 1aee36d03639..2937b0ee3d81 100644
--- a/uui/source/iahndl-ssl.cxx
+++ b/uui/source/iahndl-ssl.cxx
@@ -120,11 +120,11 @@ getLocalizedDatTimeStr(
     SvNumberFormatter *pNumberFormatter = new SvNumberFormatter( xContext, eUILang );
     OUString      aTmpStr;
     Color*      pColor = nullptr;
-    Date*       pNullDate = pNumberFormatter->GetNullDate();
+    const Date&  rNullDate = pNumberFormatter->GetNullDate();
     sal_uInt32  nFormat
         = pNumberFormatter->GetStandardFormat( css::util::NumberFormat::DATE, eUILang );
 
-    pNumberFormatter->GetOutputString( aDate - *pNullDate, nFormat, aTmpStr, &pColor );
+    pNumberFormatter->GetOutputString( aDate - rNullDate, nFormat, aTmpStr, &pColor );
     aDateTimeStr = aTmpStr + " ";
 
     nFormat = pNumberFormatter->GetStandardFormat( css::util::NumberFormat::TIME, eUILang );