Resolves: tdf#100452 class Date full (BCE,CE) proleptic Gregorian calendar

... implementing signed years with year 0 gap.
Date(31,12,-1) last day BCE
Date(1,1,1) first day CE

New class Date member functions:
* AddYears(sal_Int16) to be used instead of
aDate.SetYear(aDate.GetYear()+sal_Int16) to handle year 0 gap.
* convenience GetNextYear() to be used insted of GetYear()+1
* convenience GetPrevYear() to be used insted of GetYear()-1
* AddMonths(sal_Int32)
* operator=(const css::util::Date&)

New class DateTime member functions:
* operator=(const css::util::DateTime&)

Made some conversion ctors explicit, specifically Date(sal_Int32)

Adapted hopefully all places that used a sal_uInt16 year to use
sal_Int16 where appropriate.

Eliminated some quirks in date handling found on the fly.

Added era handling to i18npool icu calendar setting interface, which
missing was responsible for 0001-01-01 entered in Calc being set as
-0001-01-01, hence subtracting one day resulted in -0002-12-31.

Change-Id: I77b39fba9599ebd5067d7864f6c9ebe01f6f578f
Reviewed-on: https://gerrit.libreoffice.org/27049
Reviewed-by: Eike Rathke <erack@redhat.com>
Tested-by: Jenkins <ci@libreoffice.org>

9 files changed, 28 insertions, 15 deletions

diff --git a/sc/inc/docoptio.hxx b/sc/inc/docoptio.hxx
index a5f3bbfdc298..529135bb9a37 100644
--- a/sc/inc/docoptio.hxx
+++ b/sc/inc/docoptio.hxx
@@ -73,9 +73,9 @@ public:
     double GetIterEps() const               { return fIterEps; }
     void   SetIterEps( double fEps )        { fIterEps = fEps; }
 
-    void   GetDate( sal_uInt16& rD, sal_uInt16& rM, sal_uInt16& rY ) const
+    void   GetDate( sal_uInt16& rD, sal_uInt16& rM, sal_Int16& rY ) const
                                         { rD = nDay; rM = nMonth; rY = nYear;}
-    void   SetDate (sal_uInt16 nD, sal_uInt16 nM, sal_uInt16 nY)
+    void   SetDate (sal_uInt16 nD, sal_uInt16 nM, sal_Int16 nY)
                                         { nDay = nD; nMonth = nM; nYear = nY; }
     sal_uInt16 GetTabDistance() const { return nTabDistance;}
     void   SetTabDistance( sal_uInt16 nTabDist ) {nTabDistance = nTabDist;}
diff --git a/sc/source/core/data/conditio.cxx b/sc/source/core/data/conditio.cxx
index 684498c8616c..cf7af863c188 100644
--- a/sc/source/core/data/conditio.cxx
+++ b/sc/source/core/data/conditio.cxx
@@ -1692,7 +1692,7 @@ bool ScCondDateFormatEntry::IsValid( const ScAddress& rPos ) const
         case condformat::LASTMONTH:
             if( rActDate.GetMonth() == 1 )
             {
-                if( aCellDate.GetMonth() == 12 && rActDate.GetYear() == aCellDate.GetYear() + 1 )
+                if( aCellDate.GetMonth() == 12 && rActDate.GetYear() == aCellDate.GetNextYear() )
                     return true;
             }
             else if( rActDate.GetYear() == aCellDate.GetYear() )
@@ -1721,7 +1721,7 @@ bool ScCondDateFormatEntry::IsValid( const ScAddress& rPos ) const
             }
             break;
         case condformat::LASTYEAR:
-            if( rActDate.GetYear() == aCellDate.GetYear() + 1 )
+            if( rActDate.GetYear() == aCellDate.GetNextYear() )
                 return true;
             break;
         case condformat::THISYEAR:
diff --git a/sc/source/core/data/poolhelp.cxx b/sc/source/core/data/poolhelp.cxx
index 40bae0aa690f..b469155f6968 100644
--- a/sc/source/core/data/poolhelp.cxx
+++ b/sc/source/core/data/poolhelp.cxx
@@ -78,7 +78,8 @@ void ScPoolHelper::UseDocOptions() const
 {
     if (pFormTable)
     {
-        sal_uInt16 d,m,y;
+        sal_uInt16 d,m;
+        sal_Int16 y;
         aOpt.GetDate( d,m,y );
         pFormTable->ChangeNullDate( d,m,y );
         pFormTable->ChangeStandardPrec( (sal_uInt16)aOpt.GetStdPrecision() );
@@ -102,7 +103,8 @@ SvNumberFormatter* ScPoolHelper::CreateNumberFormatter() const
     p->SetColorLink( LINK(m_pSourceDoc, ScDocument, GetUserDefinedColor) );
     p->SetEvalDateFormat(NF_EVALDATEFORMAT_INTL_FORMAT);
 
-    sal_uInt16 d,m,y;
+    sal_uInt16 d,m;
+    sal_Int16 y;
     aOpt.GetDate(d, m, y);
     p->ChangeNullDate(d, m, y);
     p->ChangeStandardPrec(aOpt.GetStdPrecision());
diff --git a/sc/source/core/tool/chgviset.cxx b/sc/source/core/tool/chgviset.cxx
index 50a784f8b390..938c26591e62 100644
--- a/sc/source/core/tool/chgviset.cxx
+++ b/sc/source/core/tool/chgviset.cxx
@@ -146,7 +146,7 @@ void ScChangeViewSettings::AdjustDateMode( const ScDocument& rDoc )
                 aFirstDateTime.SetTime( 0 );
             }
             aLastDateTime = Date( Date::SYSTEM );
-            aLastDateTime.SetYear( aLastDateTime.GetYear() + 100 );
+            aLastDateTime.AddYears( 100 );
         }
         break;
         default:
diff --git a/sc/source/core/tool/docoptio.cxx b/sc/source/core/tool/docoptio.cxx
index c8ee49a93795..a84f8ae15a48 100644
--- a/sc/source/core/tool/docoptio.cxx
+++ b/sc/source/core/tool/docoptio.cxx
@@ -212,7 +212,8 @@ ScDocCfg::ScDocCfg() :
     Sequence<Any> aValues;
     const Any* pValues = nullptr;
 
-    sal_uInt16 nDateDay, nDateMonth, nDateYear;
+    sal_uInt16 nDateDay, nDateMonth;
+    sal_Int16 nDateYear;
     GetDate( nDateDay, nDateMonth, nDateYear );
 
     aNames = GetCalcPropertyNames();
@@ -246,7 +247,7 @@ ScDocCfg::ScDocCfg() :
                         if (pValues[nProp] >>= nIntVal) nDateMonth = (sal_uInt16) nIntVal;
                         break;
                     case SCCALCOPT_DATE_YEAR:
-                        if (pValues[nProp] >>= nIntVal) nDateYear = (sal_uInt16) nIntVal;
+                        if (pValues[nProp] >>= nIntVal) nDateYear = (sal_Int16) nIntVal;
                         break;
                     case SCCALCOPT_DECIMALS:
                         if (pValues[nProp] >>= nIntVal) SetStdPrecision( (sal_uInt16) nIntVal );
@@ -310,7 +311,8 @@ IMPL_LINK_NOARG_TYPED(ScDocCfg, CalcCommitHdl, ScLinkConfigItem&, void)
     Sequence<Any> aValues(aNames.getLength());
     Any* pValues = aValues.getArray();
 
-    sal_uInt16 nDateDay, nDateMonth, nDateYear;
+    sal_uInt16 nDateDay, nDateMonth;
+    sal_Int16 nDateYear;
     GetDate( nDateDay, nDateMonth, nDateYear );
 
     for(int nProp = 0; nProp < aNames.getLength(); nProp++)
diff --git a/sc/source/core/tool/interpr2.cxx b/sc/source/core/tool/interpr2.cxx
index fe4331431c02..cc735270d4fd 100644
--- a/sc/source/core/tool/interpr2.cxx
+++ b/sc/source/core/tool/interpr2.cxx
@@ -807,7 +807,8 @@ void ScInterpreter::ScGetDateDif()
         }
 
         // split dates in day, month, year for use with formats other than "d"
-        sal_uInt16 d1, m1, y1, d2, m2, y2;
+        sal_uInt16 d1, m1, d2, m2;
+        sal_Int16 y1, y2;
         Date aDate1( *( pFormatter->GetNullDate()));
         aDate1 += (long) ::rtl::math::approxFloor( nDate1 );
         y1 = aDate1.GetYear();
@@ -819,6 +820,12 @@ void ScInterpreter::ScGetDateDif()
         m2 = aDate2.GetMonth();
         d2 = aDate2.GetDay();
 
+        // Close the year 0 gap to calculate year difference.
+        if (y1 < 0 && y2 > 0)
+            ++y1;
+        else if (y1 > 0 && y2 < 0)
+            ++y2;
+
         if (  aInterval.equalsIgnoreAsciiCase( "m" ) )
         {
             // Return number of months.
@@ -871,7 +878,7 @@ void ScInterpreter::ScGetDateDif()
             {
                 if (m2 == 1)
                 {
-                    aDate1.SetYear( y2 - 1 );
+                    aDate1.SetYear( y2 == 1 ? -1 : y2 - 1 );
                     aDate1.SetMonth( 12 );
                 }
                 else
diff --git a/sc/source/ui/cctrl/checklistmenu.cxx b/sc/source/ui/cctrl/checklistmenu.cxx
index 32e2e11364fa..93f9aef01da0 100644
--- a/sc/source/ui/cctrl/checklistmenu.cxx
+++ b/sc/source/ui/cctrl/checklistmenu.cxx
@@ -1442,7 +1442,7 @@ void ScCheckListMenuWindow::addDateMember(const OUString& rsName, double nVal, b
     Date aDate = *(pFormatter->GetNullDate());
     aDate += static_cast<long>(rtl::math::approxFloor(nVal));
 
-    sal_uInt16 nYear = aDate.GetYear();
+    sal_Int16 nYear = aDate.GetYear();
     sal_uInt16 nMonth = aDate.GetMonth();
     sal_uInt16 nDay = aDate.GetDay();
 
diff --git a/sc/source/ui/optdlg/tpcalc.cxx b/sc/source/ui/optdlg/tpcalc.cxx
index 9cf30a177009..a9834f4e69aa 100644
--- a/sc/source/ui/optdlg/tpcalc.cxx
+++ b/sc/source/ui/optdlg/tpcalc.cxx
@@ -112,7 +112,8 @@ VclPtr<SfxTabPage> ScTpCalcOptions::Create( vcl::Window* pParent, const SfxItemS
 
 void ScTpCalcOptions::Reset( const SfxItemSet* /* rCoreAttrs */ )
 {
-    sal_uInt16  d,m,y;
+    sal_uInt16  d,m;
+    sal_Int16   y;
 
     *pLocalOptions  = *pOldOptions;
 
diff --git a/sc/source/ui/unoobj/optuno.cxx b/sc/source/ui/unoobj/optuno.cxx
index 925af4e63c26..ff479fe92677 100644
--- a/sc/source/ui/unoobj/optuno.cxx
+++ b/sc/source/ui/unoobj/optuno.cxx
@@ -162,7 +162,8 @@ uno::Any ScDocOptionsHelper::getPropertyValue(
         break;
         case PROP_UNO_NULLDATE:
         {
-            sal_uInt16 nD, nM, nY;
+            sal_uInt16 nD, nM;
+            sal_Int16 nY;
             rOptions.GetDate( nD, nM, nY );
             util::Date aDate( nD, nM, nY );
             aRet <<= aDate;