Fix for bug #1424, split feature segfault

git-svn-id: http://svn.osgeo.org/qgis/trunk@9712 c8812cc2-4d05-0410-92ff-de0c093fc19c

src/core/qgsgeometry.cpp

@@ -4864,7 +4864,7 @@ int QgsGeometry::splitPolygonGeometry( GEOSGeometry* splitLine, QList<QgsGeometr
   //ratio intersect geometry / geometry. This should be close to 1
   //if the polygon belongs to the input geometry
 
-  for ( int i = 0; i < GEOSGetNumGeometries( polygons ); i++ )
+  for ( int i = 0; i < getNumberOfGeometries( polygons ); i++ )
   {
     const GEOSGeometry *polygon = GEOSGetGeometryN( polygons, i );
     intersectGeometry = GEOSIntersection( mGeos, polygon );
@@ -4883,7 +4883,7 @@ int QgsGeometry::splitPolygonGeometry( GEOSGeometry* splitLine, QList<QgsGeometr
   }
 
   bool splitDone = true;
-  int nGeometriesThis = GEOSGetNumGeometries( mGeos ); //original number of geometries
+  int nGeometriesThis = getNumberOfGeometries( mGeos ); //original number of geometries
   if ( testedGeometries.size() == nGeometriesThis )
   {
     splitDone = false;
@@ -5003,6 +5003,23 @@ GEOSGeometry *QgsGeometry::nodeGeometries( const GEOSGeometry *splitLine, GEOSGe
   return unionGeometry;
 }
 
+int QgsGeometry::getNumberOfGeometries(GEOSGeometry* g) const
+{
+  if(!g)
+  {
+    return 0;
+  }
+  int geometryType = GEOSGeomTypeId(g);
+  if(geometryType == GEOS_POINT || geometryType == GEOS_LINESTRING || geometryType == GEOS_LINEARRING
+     || geometryType == GEOS_POLYGON)
+  {
+    return 1;
+  }
+
+  //calling GEOSGetNumGeometries is save for multi types and collections also in geos2
+  return GEOSGetNumGeometries(g);
+}
+
 int QgsGeometry::mergeGeometriesMultiTypeSplit( QVector<GEOSGeometry*>& splitResult )
 {
   if ( !mGeos || mDirtyGeos )

src/core/qgsgeometry.h

@@ -417,6 +417,9 @@ class CORE_EXPORT QgsGeometry
      @return the noded multiline geometry or 0 in case of error. The calling function takes ownership of the node geometry*/
     GEOSGeometry* nodeGeometries( const GEOSGeometry *splitLine, GEOSGeometry *poly ) const;
 
+    /**Returns number of single geometry in a geos geometry. Is save for geos 2 and 3*/
+    int getNumberOfGeometries(GEOSGeometry* g) const;
+
     int mergeGeometriesMultiTypeSplit( QVector<GEOSGeometry*>& splitResult );
 
     /** return point from wkb */