avoid infinite loops in dxf rendering

Change-Id: Id2eb5540241f0792cde35c444fc2c0c5b7778353

filter/source/graphicfilter/idxf/dxf2mtf.cxx

@@ -680,6 +680,10 @@ void DXF2GDIMetaFile::DrawDimensionEntity(const DXFDimensionEntity & rE, const D
 void DXF2GDIMetaFile::DrawEntities(const DXFEntities & rEntities,
                                    const DXFTransform & rTransform)
 {
+    if (rEntities.mbBeingDrawn)
+        return;
+    rEntities.mbBeingDrawn = true;
+
     sal_uLong nCount=0;
     DXFTransform aET;
     const DXFTransform * pT;
@@ -745,6 +749,8 @@ void DXF2GDIMetaFile::DrawEntities(const DXFEntities & rEntities,
         pE=pE->pSucc;
         nCount++;
     }
+
+    rEntities.mbBeingDrawn = false;
 }
 
 

filter/source/graphicfilter/idxf/dxfentrd.hxx

@@ -511,10 +511,19 @@ class DXFEntities {
 
 public:
 
-    DXFEntities();
-    ~DXFEntities();
+    DXFEntities()
+        : pFirst(nullptr)
+        , mbBeingDrawn(false)
+    {
+    }
+
+    ~DXFEntities()
+    {
+        Clear();
+    }
 
     DXFBasicEntity * pFirst; // list of entities, READ ONLY!
+    mutable bool mbBeingDrawn; // guard for loop in entity parsing
 
     void Read(DXFGroupReader & rDGR);
         // read entities per rGDR of a DXF file until a
@@ -525,18 +534,6 @@ public:
         // deletes all entities
 };
 
-inline DXFEntities::DXFEntities()
-{
-    pFirst=nullptr;
-}
-
-
-inline DXFEntities::~DXFEntities()
-{
-    Clear();
-}
-
-
 #endif