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>

2 files changed, 15 insertions, 5 deletions

diff --git a/unotools/source/i18n/localedatawrapper.cxx b/unotools/source/i18n/localedatawrapper.cxx
index 7204f66392bb..6dbd1388ba52 100644
--- a/unotools/source/i18n/localedatawrapper.cxx
+++ b/unotools/source/i18n/localedatawrapper.cxx
@@ -1134,6 +1134,16 @@ static sal_Unicode* ImplAddUNum( sal_Unicode* pBuf, sal_uInt64 nNumber, int nMin
     return pBuf;
 }
 
+static sal_Unicode* ImplAddNum( sal_Unicode* pBuf, sal_Int64 nNumber, int nMinLen )
+{
+    if (nNumber < 0)
+    {
+        *pBuf++ = '-';
+        nNumber = -nNumber;
+    }
+    return ImplAddUNum( pBuf, nNumber, nMinLen);
+}
+
 static sal_Unicode* ImplAdd2UNum( sal_Unicode* pBuf, sal_uInt16 nNumber, bool bLeading )
 {
     DBG_ASSERT( nNumber < 100, "ImplAdd2UNum() - Number >= 100" );
@@ -1324,7 +1334,7 @@ OUString LocaleDataWrapper::getDate( const Date& rDate ) const
     sal_Unicode* pBuf = aBuf;
     sal_uInt16  nDay    = rDate.GetDay();
     sal_uInt16  nMonth  = rDate.GetMonth();
-    sal_uInt16  nYear   = rDate.GetYear();
+    sal_Int16   nYear   = rDate.GetYear();
     sal_uInt16  nYearLen;
 
     if ( true /* IsDateCentury() */ )
@@ -1342,17 +1352,17 @@ OUString LocaleDataWrapper::getDate( const Date& rDate ) const
             pBuf = ImplAddString( pBuf, getDateSep() );
             pBuf = ImplAdd2UNum( pBuf, nMonth, true /* IsDateMonthLeadingZero() */ );
             pBuf = ImplAddString( pBuf, getDateSep() );
-            pBuf = ImplAddUNum( pBuf, nYear, nYearLen );
+            pBuf = ImplAddNum( pBuf, nYear, nYearLen );
         break;
         case MDY :
             pBuf = ImplAdd2UNum( pBuf, nMonth, true /* IsDateMonthLeadingZero() */ );
             pBuf = ImplAddString( pBuf, getDateSep() );
             pBuf = ImplAdd2UNum( pBuf, nDay, true /* IsDateDayLeadingZero() */ );
             pBuf = ImplAddString( pBuf, getDateSep() );
-            pBuf = ImplAddUNum( pBuf, nYear, nYearLen );
+            pBuf = ImplAddNum( pBuf, nYear, nYearLen );
         break;
         default:
-            pBuf = ImplAddUNum( pBuf, nYear, nYearLen );
+            pBuf = ImplAddNum( pBuf, nYear, nYearLen );
             pBuf = ImplAddString( pBuf, getDateSep() );
             pBuf = ImplAdd2UNum( pBuf, nMonth, true /* IsDateMonthLeadingZero() */ );
             pBuf = ImplAddString( pBuf, getDateSep() );
diff --git a/unotools/source/ucbhelper/ucblockbytes.cxx b/unotools/source/ucbhelper/ucblockbytes.cxx
index f894c1cf7e1a..1e88ab7287b4 100644
--- a/unotools/source/ucbhelper/ucblockbytes.cxx
+++ b/unotools/source/ucbhelper/ucblockbytes.cxx
@@ -176,7 +176,7 @@ void SAL_CALL UcbPropertiesChangeListener_Impl::propertiesChange ( const Sequenc
 
                     if (aName.compareToIgnoreAsciiCaseAscii("Expires") == 0)
                     {
-                        DateTime aExpires (0, 0);
+                        DateTime aExpires( DateTime::EMPTY );
                         if (INetMIMEMessage::ParseDateField (aValue, aExpires))
                         {
                             aExpires.ConvertToLocalTime();