fdo#73466 SwTxtSizeInfo / SwTxtInputFldPortion: invalid string access

Change-Id: Ibd74e3b0cd45fa3bf6fd4135866b22acd16e372e

sw/source/core/text/inftxt.hxx

@@ -268,7 +268,7 @@ public:
     inline const  SwViewOption &GetOpt() const { return *m_pOpt; }
     inline const OUString &GetTxt() const { return *m_pTxt; }
     inline sal_Unicode GetChar( const sal_Int32 nPos ) const
-    { if (m_pTxt && !m_pTxt->isEmpty()) return (*m_pTxt)[ nPos ]; return 0; }
+    { if (m_pTxt && nPos < m_pTxt->getLength()) return (*m_pTxt)[ nPos ]; return 0; }
 
     KSHORT      GetTxtHeight() const;
 

sw/source/core/text/portxt.cxx

@@ -780,7 +780,7 @@ sal_Bool SwTxtInputFldPortion::GetExpTxt( const SwTxtSizeInfo &rInf, OUString &r
     {
         --nLen;
     }
-    rTxt = rInf.GetTxt().copy( nIdx, nLen );
+    rTxt = rInf.GetTxt().copy( nIdx, std::min( nLen, rInf.GetTxt().getLength() - nIdx ) );
 
     return sal_True;
 }