Add EditPaM::operator !() and simplify EditSelection::IsInvalid

Change-Id: Id47d77e63eff2267f5e4112b88dfb90c3ec95bd8

editeng/source/editeng/editdoc.cxx

@@ -1212,13 +1212,6 @@ EditSelection& EditSelection::operator = ( const EditPaM& rPaM )
     return *this;
 }
 
-bool EditSelection::IsInvalid() const
-{
-    EditPaM aEmptyPaM;
-
-    return ( aStartPaM == aEmptyPaM ) || ( aEndPaM == aEmptyPaM );
-}
-
 void EditSelection::Adjust( const EditDoc& rNodes )
 {
     DBG_ASSERT( aStartPaM.GetIndex() <= aStartPaM.GetNode()->Len(), "Index out of range in Adjust(1)" );

editeng/source/editeng/editdoc.hxx

@@ -332,6 +332,7 @@ public:
     EditPaM&    operator = ( const EditPaM& rPaM );
     friend bool operator == ( const EditPaM& r1, const EditPaM& r2 );
     friend bool operator != ( const EditPaM& r1, const EditPaM& r2 );
+    bool operator !() const { return !pNode && !nIndex; }
 };
 
 #define PORTIONKIND_TEXT        0
@@ -711,7 +712,7 @@ public:
     const EditPaM&  Max() const         { return aEndPaM; }
 
     bool            HasRange() const    { return aStartPaM != aEndPaM; }
-    bool            IsInvalid() const;
+    bool            IsInvalid() const { return !aStartPaM || !aEndPaM; }
     bool            DbgIsBuggy( EditDoc& rDoc );
 
     void            Adjust( const EditDoc& rNodes );