Fix: nNodeCnt could be set to negative value

Change-Id: I82e9b150e97e733c4063f7498dc026e0c9f903c0
Reviewed-on: https://gerrit.libreoffice.org/53660Reviewed-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>
Tested-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>
Reviewed-on: https://gerrit.libreoffice.org/53667Tested-by: Jenkins <ci@libreoffice.org>

sw/source/core/docnode/nodes.cxx

@@ -1732,7 +1732,7 @@ void SwNodes::CopyNodes( const SwNodeRange& rRange,
     SwNodeIndex aOrigInsPos( rIndex, -1 ); // original insertion position
     int nLevel = 0;                        // level counter
 
-    for( sal_uLong nNodeCnt = aRg.aEnd.GetIndex() - aRg.aStart.GetIndex();
+    for( long nNodeCnt = aRg.aEnd.GetIndex() - aRg.aStart.GetIndex();
             nNodeCnt > 0; --nNodeCnt )
     {
         pCurrentNode = &aRg.aStart.GetNode();
@@ -1744,7 +1744,7 @@ void SwNodes::CopyNodes( const SwNodeRange& rRange,
                     pDoc->GetNodes().GetEndOfInserts().StartOfSectionIndex()
                     < aInsPos.GetIndex() )
             {
-                sal_uLong nDistance =
+                const long nDistance =
                     ( pCurrentNode->EndOfSectionIndex() -
                         aRg.aStart.GetIndex() );
                 if (nDistance < nNodeCnt)
@@ -1785,7 +1785,7 @@ void SwNodes::CopyNodes( const SwNodeRange& rRange,
                 SwNodeIndex nStt( aInsPos, -1 );
                 SwTableNode* pTableNd = static_cast<SwTableNode*>(pCurrentNode)->
                                         MakeCopy( pDoc, aInsPos );
-                sal_uLong nDistance = aInsPos.GetIndex() - nStt.GetIndex() - 2;
+                const long nDistance = aInsPos.GetIndex() - nStt.GetIndex() - 2;
                 if (nDistance < nNodeCnt)
                     nNodeCnt -= nDistance;
                 else
@@ -1813,7 +1813,7 @@ void SwNodes::CopyNodes( const SwNodeRange& rRange,
                 SwSectionNode* pSectNd = static_cast<SwSectionNode*>(pCurrentNode)->
                                     MakeCopy( pDoc, aInsPos );
 
-                sal_uLong nDistance = aInsPos.GetIndex() - nStt.GetIndex() - 2;
+                const long nDistance = aInsPos.GetIndex() - nStt.GetIndex() - 2;
                 if (nDistance < nNodeCnt)
                     nNodeCnt -= nDistance;
                 else