use std::filesystem::path

libsrc/core/archive.hpp

@@ -5,6 +5,7 @@
 #include <array>                // for array
 #include <complex>              // for complex
 #include <cstring>              // for size_t, strlen
+#include <filesystem>           // for path
 #include <fstream>              // for ifstream, ofstream
 #include <functional>           // for function
 #include <map>                  // for map
@@ -740,7 +741,7 @@ namespace ngcore
     BinaryOutArchive(std::shared_ptr<std::ostream>&& astream)
       : Archive(true), stream(std::move(astream))
     { }
-    BinaryOutArchive(const std::string& filename)
+    BinaryOutArchive(const std::filesystem::path& filename)
       : BinaryOutArchive(std::make_shared<std::ofstream>(filename)) {}
     ~BinaryOutArchive () override { FlushBuffer(); }
 
@@ -828,7 +829,7 @@ namespace ngcore
     BinaryInArchive (std::shared_ptr<std::istream>&& astream)
       : Archive(false), stream(std::move(astream))
     { }
-    BinaryInArchive (const std::string& filename)
+    BinaryInArchive (const std::filesystem::path& filename)
       : BinaryInArchive(std::make_shared<std::ifstream>(filename)) { ; }
 
     using Archive::operator&;
@@ -903,7 +904,7 @@ namespace ngcore
     TextOutArchive (std::shared_ptr<std::ostream>&& astream)
       : Archive(true), stream(std::move(astream))
     { }
-    TextOutArchive (const std::string& filename) :
+    TextOutArchive (const std::filesystem::path& filename) :
       TextOutArchive(std::make_shared<std::ofstream>(filename)) { }
 
     using Archive::operator&;
@@ -958,7 +959,7 @@ namespace ngcore
     TextInArchive (std::shared_ptr<std::istream>&& astream) :
       Archive(false), stream(std::move(astream))
     { }
-    TextInArchive (const std::string& filename)
+    TextInArchive (const std::filesystem::path& filename)
       : TextInArchive(std::make_shared<std::ifstream>(filename)) {}
 
     using Archive::operator&;

libsrc/core/python_ngcore.hpp

@@ -6,6 +6,7 @@
 #include <pybind11/operators.h>
 #include <pybind11/numpy.h>
 #include <pybind11/stl.h>
+#include <pybind11/stl/filesystem.h>
 
 #include "array.hpp"
 #include "table.hpp"

libsrc/core/utils.cpp

@@ -112,13 +112,12 @@ namespace ngcore
 #endif
   }
 
-  NGCORE_API std::string GetTempFilename()
+  NGCORE_API std::filesystem::path GetTempFilename()
   {
       static int counter = 0;
       auto path = std::filesystem::temp_directory_path();
-      std::string filename = ".temp_netgen_file_"+ToString(counter++)+"_"+ToString(GetTimeCounter());
+      path += ".temp_netgen_file_"+ToString(counter++)+"_"+ToString(GetTimeCounter());
-      path.append(filename);
+      return path;
-      return path.string();
   }
 
 } // namespace ngcore

libsrc/core/utils.hpp

@@ -3,6 +3,7 @@
 
 #include <atomic>
 #include <chrono>
+#include <filesystem>
 #include <map>
 #include <ostream>
 #include <sstream>
@@ -81,6 +82,22 @@ namespace ngcore
       return ss.str();
   }
 
+  inline std::string ToLower( const std::string & s )
+  {
+    std::string res;
+    res.reserve(s.size());
+
+    for(auto & c : res)
+        res.push_back(tolower(c));
+
+    return res;
+  }
+
+  inline std::string ToLower( const std::filesystem::path & p )
+  {
+    return ToLower(p.string());
+  }
+
   template<typename T1, typename T2>
   std::ostream& operator << (std::ostream& ost, const std::map<T1,T2>& map)
   {
@@ -201,7 +218,7 @@ namespace ngcore
   NGCORE_API int GetCompiledSIMDSize();
   NGCORE_API bool IsRangeCheckEnabled();
 
-  NGCORE_API std::string GetTempFilename();
+  NGCORE_API std::filesystem::path GetTempFilename();
 
 } // namespace ngcore
 

libsrc/csg/csgeom.cpp

@@ -264,7 +264,7 @@ namespace netgen
   }
 
 
-  void CSGeometry :: Save (string filename) const
+  void CSGeometry :: Save (const filesystem::path & filename) const
   {
     ofstream ost (filename.c_str());
     Save (ost);
@@ -1619,21 +1619,21 @@ namespace netgen
   class CSGeometryRegister : public GeometryRegister
   {
   public:
-    virtual NetgenGeometry * Load (string filename) const;
+    virtual NetgenGeometry * Load (const filesystem::path & filename) const;
     virtual NetgenGeometry * LoadFromMeshFile (istream & ist, string token) const;
     // virtual VisualScene * GetVisualScene (const NetgenGeometry * geom) const;
   };
 
   extern CSGeometry * ParseCSG (istream & istr, CSGeometry *instance=nullptr);
 
-  NetgenGeometry *  CSGeometryRegister :: Load (string filename) const
+  NetgenGeometry *  CSGeometryRegister :: Load (const filesystem::path & filename) const
   {
-    const char * cfilename = filename.c_str();
+    string extension = filename.extension().string();
-    if (strcmp (&cfilename[strlen(cfilename)-3], "geo") == 0)
+    if (extension == ".geo")
       {
-	PrintMessage (1, "Load CSG geometry file ", cfilename);
+	PrintMessage (1, "Load CSG geometry file ", filename);
 
-	ifstream infile(cfilename);
+	ifstream infile(filename);
 
 	CSGeometry * hgeom = ParseCSG (infile);
 	if (!hgeom)
@@ -1643,19 +1643,17 @@ namespace netgen
 	return hgeom;
       }
 
-    if (strcmp (&cfilename[strlen(cfilename)-3], "ngg") == 0)
+    if (extension == ".ngg")
       {
-	PrintMessage (1, "Load new CSG geometry file ", cfilename);
+	PrintMessage (1, "Load new CSG geometry file ", filename);
 
-	ifstream infile(cfilename);
+	ifstream infile(filename);
 	CSGeometry * hgeom = new CSGeometry("");
 	hgeom -> Load (infile);
 
 	return hgeom;
       }
     
-
-    
     return NULL;
   }
 

libsrc/csg/csgeom.hpp

@@ -182,7 +182,7 @@ namespace netgen
 
     void Clean ();
 
-    virtual void Save (string filename) const override;
+    virtual void Save (const filesystem::path & filename) const override;
     void Save (ostream & ost) const;
     void Load (istream & ist);
 

libsrc/csg/csgpkg.cpp

@@ -547,86 +547,10 @@ namespace netgen
   }
 
 
-  /*
-  class CSGeometryRegister : public GeometryRegister
-  {
-  public:
-    virtual NetgenGeometry * Load (string filename) const;
-    virtual NetgenGeometry * LoadFromMeshFile (istream & ist) const;
-    virtual VisualScene * GetVisualScene (const NetgenGeometry * geom) const;
-  };
-
-  extern CSGeometry * ParseCSG (istream & istr);
-
-  NetgenGeometry *  CSGeometryRegister :: Load (string filename) const
-  {
-    const char * cfilename = filename.c_str();
-    if (strcmp (&cfilename[strlen(cfilename)-3], "geo") == 0)
-      {
-	PrintMessage (1, "Load CSG geometry file ", cfilename);
-
-	ifstream infile(cfilename);
-
-	CSGeometry * hgeom = ParseCSG (infile);
-	if (!hgeom)
-	  throw NgException ("geo-file should start with 'algebraic3d'");
-
-	hgeom -> FindIdenticSurfaces(1e-8 * hgeom->MaxSize()); 
-	return hgeom;
-      }
-
-    if (strcmp (&cfilename[strlen(cfilename)-3], "ngg") == 0)
-      {
-	PrintMessage (1, "Load new CSG geometry file ", cfilename);
-
-	ifstream infile(cfilename);
-	CSGeometry * hgeom = new CSGeometry("");
-	hgeom -> Load (infile);
-
-	return hgeom;
-      }
-
-
-    
-    return NULL;
-  }
-
-  NetgenGeometry * CSGeometryRegister :: LoadFromMeshFile (istream & ist) const 
-  {
-    string auxstring;
-    if (ist.good())
-      {
-	ist >> auxstring;
-	if (auxstring == "csgsurfaces")
-	  {
-	    CSGeometry * geometry = new CSGeometry ("");
-	    geometry -> LoadSurfaces(ist);
-	    return geometry;
-	  }
-	// else
-	// ist.putback (auxstring);
-      }
-    return NULL;
-  }
-
-  VisualScene * CSGeometryRegister :: GetVisualScene (const NetgenGeometry * geom) const
-  {
-    CSGeometry * geometry = dynamic_cast<CSGeometry*> (ng_geometry.get());
-    if (geometry)
-      {
-	vsgeom.SetGeometry (geometry);
-	return &vsgeom;
-      }
-    return NULL;
-  }
-  */
-
-
-
   class CSGeometryVisRegister : public GeometryRegister
   {
   public:
-    virtual NetgenGeometry * Load (string filename) const { return NULL; }
+    virtual NetgenGeometry * Load (const filesystem::path & filename) const { return NULL; }
     virtual VisualScene * GetVisualScene (const NetgenGeometry * geom) const;
   };
 

libsrc/general/gzstream.cpp

@@ -44,7 +44,7 @@ namespace GZSTREAM_NAMESPACE {
 // class gzstreambuf:
 // --------------------------------------
 
-gzstreambuf* gzstreambuf::open( const char* name, int open_mode) {
+gzstreambuf* gzstreambuf::open( const filesystem::path & name, int open_mode) {
     if ( is_open())
         return (gzstreambuf*)0;
     mode = open_mode;
@@ -60,7 +60,11 @@ gzstreambuf* gzstreambuf::open( const char* name, int open_mode) {
         *fmodeptr++ = 'w';
     *fmodeptr++ = 'b';
     *fmodeptr = '\0';
-    file = gzopen( name, fmode);
+#ifdef WIN32
+    file = gzopen_w( name.c_str(), fmode);
+#else // WIN32
+    file = gzopen( name.c_str(), fmode);
+#endif // WIN32
     if (file == 0)
         return (gzstreambuf*)0;
     opened = 1;
@@ -139,17 +143,17 @@ int gzstreambuf::sync() {
 // class gzstreambase:
 // --------------------------------------
 
-gzstreambase::gzstreambase( const char* name, int mode) {
+gzstreambase::gzstreambase( const filesystem::path & name, int mode) {
     init( &buf);
-    open( name, mode);
+    open( name.c_str(), mode);
 }
 
 gzstreambase::~gzstreambase() {
     buf.close();
 }
 
-void gzstreambase::open( const char* name, int open_mode) {
+void gzstreambase::open( const filesystem::path & name, int open_mode) {
-    if ( ! buf.open( name, open_mode))
+    if ( ! buf.open( name.c_str(), open_mode))
         clear( rdstate() | std::ios::badbit);
 }
 

libsrc/general/gzstream.h

@@ -62,7 +62,7 @@ public:
         // ASSERT: both input & output capabilities will not be used together
     }
     int is_open() { return opened; }
-    gzstreambuf* open( const char* name, int open_mode);
+    gzstreambuf* open( const filesystem::path & name, int open_mode);
     gzstreambuf* close();
     ~gzstreambuf() { close(); }
     
@@ -76,9 +76,9 @@ protected:
     gzstreambuf buf;
 public:
     gzstreambase() { init(&buf); }
-    DLL_HEADER gzstreambase( const char* name, int open_mode);
+    DLL_HEADER gzstreambase( const filesystem::path & name, int open_mode);
     DLL_HEADER ~gzstreambase();
-    void open( const char* name, int open_mode);
+    void open( const filesystem::path & name, int open_mode);
     void close();
     gzstreambuf* rdbuf() { return &buf; }
 };
@@ -92,10 +92,10 @@ public:
 class DLL_HEADER igzstream : public gzstreambase, public std::istream {
 public:
     igzstream() : std::istream( &buf) {} 
-    igzstream( const char* name, int open_mode = std::ios::in)
+    igzstream( const filesystem::path & name, int open_mode = std::ios::in)
         : gzstreambase( name, open_mode), std::istream( &buf) {}  
     gzstreambuf* rdbuf() { return gzstreambase::rdbuf(); }
-    void open( const char* name, int open_mode = std::ios::in) {
+    void open( const filesystem::path & name, int open_mode = std::ios::in) {
         gzstreambase::open( name, open_mode);
     }
 };
@@ -103,10 +103,10 @@ public:
 class DLL_HEADER ogzstream : public gzstreambase, public std::ostream {
 public:
     ogzstream() : std::ostream( &buf) {}
-    ogzstream( const char* name, int mode = std::ios::out)
+    ogzstream( const filesystem::path & name, int mode = std::ios::out)
         : gzstreambase( name, mode), std::ostream( &buf) {}  
     gzstreambuf* rdbuf() { return gzstreambase::rdbuf(); }
-    void open( const char* name, int open_mode = std::ios::out) {
+    void open( const filesystem::path & name, int open_mode = std::ios::out) {
         gzstreambase::open( name, open_mode);
     }
 };

libsrc/general/mystring.cpp

@@ -223,6 +223,10 @@ MyStr::MyStr(const string & st)
   strcpy (str, st.c_str());
 }
 
+MyStr::MyStr(const filesystem::path & path)
+    : MyStr(path.string())
+{ }
+
 
 
 MyStr MyStr::Left(unsigned r)

libsrc/general/mystring.hpp

@@ -19,6 +19,8 @@
 #ifndef MYSTRING__H
 #define MYSTRING__H
 
+#include <filesystem>
+
 namespace netgen
 {
 
@@ -58,6 +60,7 @@ public:
   MyStr(const Point3d& p);
   MyStr(const Vec3d& p);
   MyStr(const string & st);
+  MyStr(const filesystem::path & st);
 
   ~MyStr();
   MyStr Left(unsigned);

libsrc/geom2d/geom2dpkg.cpp

@@ -21,7 +21,7 @@ namespace netgen
   class SplineGeometryVisRegister : public GeometryRegister
   {
   public:
-    virtual NetgenGeometry * Load (string filename) const { return NULL; }
+    virtual NetgenGeometry * Load (const filesystem::path & filename) const { return NULL; }
     virtual VisualScene * GetVisualScene (const NetgenGeometry * geom) const;
   };
 

libsrc/geom2d/geometry2d.cpp

@@ -92,7 +92,7 @@ namespace netgen
     return Vec<3> (0,0,1);
   }
 
-  void SplineGeometry2d :: Load (const char * filename)
+  void SplineGeometry2d :: Load (const filesystem::path & filename)
   {
 
     ifstream infile;
@@ -104,7 +104,7 @@ namespace netgen
   
     if ( ! infile.good() )
       throw NgException(string ("Input file '") + 
-			string (filename) +
+			filename.string() +
 			string ("' not available!"));
 
     TestComment ( infile );
@@ -1075,21 +1075,20 @@ namespace netgen
   class SplineGeometryRegister : public GeometryRegister
   {
   public:
-    virtual NetgenGeometry * Load (string filename) const;
+    virtual NetgenGeometry * Load (const filesystem::path & filename) const;
   };
 
-  NetgenGeometry *  SplineGeometryRegister :: Load (string filename) const
+  NetgenGeometry *  SplineGeometryRegister :: Load (const filesystem::path & filename) const
   {
-    const char * cfilename = filename.c_str();
+    string ext = ToLower(filename.extension());
-    if (strcmp (&cfilename[strlen(cfilename)-4], "in2d") == 0)
+    if (ext == ".in2d")
       {
-	PrintMessage (1, "Load 2D-Spline geometry file ", cfilename);
+	PrintMessage (1, "Load 2D-Spline geometry file ", filename);
 
-
+	ifstream infile(filename);
-	ifstream infile(cfilename);
 
 	SplineGeometry2d * hgeom = new SplineGeometry2d();
-	hgeom -> Load (cfilename);
+	hgeom -> Load (filename);
 	return hgeom;
       }
     

libsrc/geom2d/geometry2d.hpp

@@ -143,7 +143,7 @@ namespace netgen
   public:
     DLL_HEADER virtual ~SplineGeometry2d();
 
-    DLL_HEADER void Load (const char * filename);
+    DLL_HEADER void Load (const filesystem::path & filename);
 
     DLL_HEADER void LoadData( ifstream & infile );
     DLL_HEADER void LoadDataNew ( ifstream & infile );

libsrc/interface/read_fnf_mesh.cpp

@@ -60,9 +60,9 @@ namespace netgen
 
   
   void ReadFNFFormat (Mesh & mesh, 
-                      const string & filename)
+                      const filesystem::path & filename)
   {
-    ifstream fin (filename.c_str());
+    ifstream fin (filename);
 
     string buf;
 

libsrc/interface/readtetmesh.cpp

@@ -20,10 +20,8 @@ namespace netgen
 
 
   void ReadTETFormat (Mesh & mesh, 
-                      const string & hfilename)
+                      const filesystem::path & filename)
   {
-    const char * filename = hfilename.c_str();
-
     cout << "Reading .tet mesh" << endl;
 
     ifstream in (filename);

libsrc/interface/readuser.cpp

@@ -15,22 +15,18 @@
 namespace netgen
 {
   void ReadFile (Mesh & mesh,
-                 const string & hfilename)
+                 const filesystem::path & filename)
   {
     PrintMessage(3, "Read User File");
 
-    const char * filename = hfilename.c_str();
+    auto ext = filename.extension();
 
     char reco[100];
     int np, nbe;
 
 
 
-    // ".surf" - mesh
+    if ( ext == ".surf" )
-  
-    if ( (strlen (filename) > 5) &&
-         strcmp (&filename[strlen (filename)-5], ".surf") == 0 )
-    
       {
         cout << "Surface file" << endl;
       
@@ -80,11 +76,7 @@ namespace netgen
       }
   
   
-  
+    if ( ext == ".unv" )
-
-  
-    if ( (strlen (filename) > 4) &&
-         strcmp (&filename[strlen (filename)-4], ".unv") == 0 )
       {  
         char reco[100];
         // int invert;
@@ -407,8 +399,7 @@ namespace netgen
 
     // fepp format2d:
   
-    if ( (strlen (filename) > 7) &&
+    if ( ext == ".mesh2d" )
-         strcmp (&filename[strlen (filename)-7], ".mesh2d") == 0 )
       {
         cout << "Reading FEPP2D Mesh" << endl;
       
@@ -449,8 +440,7 @@ namespace netgen
       }
 
   
-    else if ( (strlen (filename) > 5) &&
+    else if ( ext == ".mesh" )
-              strcmp (&filename[strlen (filename)-5], ".mesh") == 0 )
       {
         cout << "Reading Neutral Format" << endl;
       
@@ -522,21 +512,17 @@ namespace netgen
       }
 
 
-    if ( (strlen (filename) > 4) &&
+    if ( ext == ".emt" )
-         strcmp (&filename[strlen (filename)-4], ".emt") == 0 )
       {
         ifstream inemt (filename);
       
-        string pktfile = filename;
+        auto pktfile = filename;
-        int len = strlen (filename);
+        pktfile.replace_extension("pkt");
-        pktfile[len-3] = 'p';
-        pktfile[len-2] = 'k';
-        pktfile[len-1] = 't';
         cout << "pktfile = " << pktfile << endl;
 
         int np, nse, i;
         int bcprop;
-        ifstream inpkt (pktfile.c_str());
+        ifstream inpkt (pktfile);
         inpkt >> np;
         NgArray<double> values(np);
         for (i = 1; i <= np; i++)
@@ -629,31 +615,20 @@ namespace netgen
 
 
     // .tet mesh
-    if ( (strlen (filename) > 4) &&
+    if ( ext == ".tet" )
-         strcmp (&filename[strlen (filename)-4], ".tet") == 0 )
-      {
         ReadTETFormat (mesh, filename);
-      }
-
 
     // .fnf mesh (FNF - PE neutral format)
-    if ( (strlen (filename) > 4) &&
+    if ( ext == ".fnf" )
-         strcmp (&filename[strlen (filename)-4], ".fnf") == 0 )
-      {
         ReadFNFFormat (mesh, filename);
-      }
 
     // .cgns file - CFD General Notation System
-    if ( (strlen (filename) > 5) &&
+    if ( ext == ".cgns" )
-         strcmp (&filename[strlen (filename)-5], ".cgns") == 0 )
-      {
         ReadCGNSMesh (mesh, filename);
-      }
 
-    if ( ( (strlen (filename) > 4) && strcmp (&filename[strlen (filename)-4], ".stl") == 0 ) ||
+    if ( ext == ".stl" || ext == ".stlb" )
-         ( (strlen (filename) > 5) && strcmp (&filename[strlen (filename)-5], ".stlb") == 0 ) )
       {
-        ifstream ist{string{filename}};
+        ifstream ist{filename};
         auto geom = shared_ptr<STLGeometry>(STLGeometry::Load(ist));
 
         mesh.SetDimension (3);

libsrc/interface/rw_cgns.cpp

@@ -629,12 +629,12 @@ namespace netgen::cg
 
 namespace netgen
 {
-  int ReadCGNSMesh (Mesh & mesh, const string & filename, Array<unique_ptr<cg::Zone>> & zones)
+  int ReadCGNSMesh (Mesh & mesh, const filesystem::path & filename, Array<unique_ptr<cg::Zone>> & zones)
     {
       mesh.SetDimension(3);
       static Timer tall("CGNS::ReadMesh"); RegionTimer rtall(tall);
       int fn;
-      cg_open(filename.c_str(),CG_MODE_READ,&fn);
+      cg_open(filename.string().c_str(),CG_MODE_READ,&fn);
 
       int base = 1;
       int nzones;
@@ -698,7 +698,7 @@ namespace netgen
       return fn;
     }
 
-  void ReadCGNSMesh (Mesh & mesh, const string & filename)
+  void ReadCGNSMesh (Mesh & mesh, const filesystem::path & filename)
     {
       Array<unique_ptr<cg::Zone>> zones;
       int fn = ReadCGNSMesh(mesh, filename, zones);
@@ -706,7 +706,7 @@ namespace netgen
     }
 
   // Reads mesh and solutions of .csns file
-  tuple<shared_ptr<Mesh>, vector<string>, vector<Array<double>>, vector<int>> ReadCGNSFile(string filename, int base)
+  tuple<shared_ptr<Mesh>, vector<string>, vector<Array<double>>, vector<int>> ReadCGNSFile(const filesystem::path & filename, int base)
     {
       static Timer tall("CGNS::ReadFile"); RegionTimer rtall(tall);
 
@@ -775,11 +775,11 @@ namespace netgen
 
     }
 
-  void WriteCGNSMesh (const Mesh & mesh, const string & filename)
+  void WriteCGNSMesh (const Mesh & mesh, const filesystem::path & filename)
     {
       static Timer tall("CGNS::WriteMesh"); RegionTimer rtall(tall);
       int fn, base, zone;
-      cg_open(filename.c_str(),CG_MODE_WRITE,&fn);
+      cg_open(filename.string().c_str(),CG_MODE_WRITE,&fn);
 
       WriteCGNSMesh(mesh, fn, base, zone);
 
@@ -787,11 +787,11 @@ namespace netgen
     }
 
 
-  void WriteCGNSFile(shared_ptr<Mesh> mesh, string filename, vector<string> fields, vector<Array<double>> values, vector<int> locations)
+  void WriteCGNSFile(shared_ptr<Mesh> mesh, const filesystem::path & filename, vector<string> fields, vector<Array<double>> values, vector<int> locations)
   {
       static Timer tall("CGNS::WriteFile"); RegionTimer rtall(tall);
       int fn, base, zone;
-      cg_open(filename.c_str(),CG_MODE_WRITE,&fn);
+      cg_open(filename.string().c_str(),CG_MODE_WRITE,&fn);
 
       WriteCGNSMesh(*mesh, fn, base, zone);
 
@@ -814,22 +814,22 @@ namespace netgen
 
 namespace netgen
 {
-  void ReadCGNSMesh (Mesh & mesh, const string & filename)
+  void ReadCGNSMesh (Mesh & mesh, const filesystem::path & filename)
     {
       PrintMessage(1, "Could not import CGNS mesh: Netgen was built without CGNS support");
     }
 
-  tuple<shared_ptr<Mesh>, vector<string>, vector<Array<double>>, vector<int>> ReadCGNSFile(string filename, int base)
+  tuple<shared_ptr<Mesh>, vector<string>, vector<Array<double>>, vector<int>> ReadCGNSFile(const filesystem::path & filename, int base)
     {
       throw Exception("Netgen was built without CGNS support");
     }
 
-  void WriteCGNSMesh (const Mesh & mesh, const string & filename)
+  void WriteCGNSMesh (const Mesh & mesh, const filesystem::path & filename)
     {
       PrintMessage(1, "Could not write CGNS mesh: Netgen was built without CGNS support");
     }
 
-  void WriteCGNSFile(shared_ptr<Mesh> mesh, string filename, vector<string> fields, vector<Array<double>> values, vector<int> locations)
+  void WriteCGNSFile(shared_ptr<Mesh> mesh, const filesystem::path & filename, vector<string> fields, vector<Array<double>> values, vector<int> locations)
     {
       throw Exception("Netgen was built without CGNS support");
     }

libsrc/interface/writeOpenFOAM15x.cpp

@@ -597,7 +597,7 @@ namespace netgen
 
 
 
-   void WriteOpenFOAM15xFormat (const Mesh & mesh, const string & casename, const bool compressed)
+   void WriteOpenFOAM15xFormat (const Mesh & mesh, const filesystem::path & dirname, const bool compressed)
    {
       bool error = false;
       char casefiles[256];
@@ -639,22 +639,12 @@ namespace netgen
       }
 
 
-      cout << "Writing OpenFOAM 1.5+ Mesh files to case: " << casename << "\n";
+      cout << "Writing OpenFOAM 1.5+ Mesh files to case: " << dirname.string() << "\n";
 
       // Create the case directory if it does not already exist
       // NOTE: This needs to be improved for the Linux variant....!!!
-   #ifdef WIN32
+      auto mesh_dir = filesystem::path(dirname).append("constant").append("polyMesh");
-      char casedir[256];
+      filesystem::create_directories(mesh_dir);
-      sprintf(casedir, "mkdir %s\\constant\\polyMesh", casename.c_str());
-      system(casedir);
-   #else
-      char casedir[256];
-      mkdir(casename.c_str(), S_IRWXU|S_IRWXG);
-      sprintf(casedir, "%s/constant", casename.c_str());
-      mkdir(casedir, S_IRWXU|S_IRWXG);
-      sprintf(casedir, "%s/constant/polyMesh", casename.c_str());
-      mkdir(casedir, S_IRWXU|S_IRWXG);
-   #endif
 
       // Open handles to the five required mesh files
       // points
@@ -662,59 +652,21 @@ namespace netgen
       // owner
       // neighbour
       // boundary
-	  ostream *outfile_pnts;
-	  ostream *outfile_faces;
-	  ostream *outfile_own;
-	  ostream *outfile_nei;
-	  ostream *outfile_bnd;
 
-	  if(compressed)
+      auto get_name = [compressed, &mesh_dir]( string s ) {
-	  {
+          auto p = filesystem::path(mesh_dir).append(s);
-		  sprintf(casefiles, "%s/constant/polyMesh/points.gz", casename.c_str());
+          if(compressed)
-		  outfile_pnts = new ogzstream(casefiles);
+              p.concat(".gz");
-	  }
+          return p;
-	  else
+      };
-	  {
-		  sprintf(casefiles, "%s/constant/polyMesh/points", casename.c_str());
-		  outfile_pnts = new ofstream(casefiles);
-	  }
 
-	  if(compressed)
+      auto outfile_pnts  = make_unique<ofstream>(get_name("points"));
-	  {
+      auto outfile_faces = make_unique<ofstream>(get_name("faces"));
-		  sprintf(casefiles, "%s/constant/polyMesh/faces.gz", casename.c_str());
+      auto outfile_own   = make_unique<ofstream>(get_name("owner"));
-		  outfile_faces = new ogzstream(casefiles);
+      auto outfile_nei   = make_unique<ofstream>(get_name("neighbor"));
-	  }
-	  else
-	  {
-		  sprintf(casefiles, "%s/constant/polyMesh/faces", casename.c_str());
-		  outfile_faces = new ofstream(casefiles);
-	  }
 
-	  if(compressed)
+      // Note... the boundary file is not compressed
-	  {
+      auto outfile_bnd   = make_unique<ofstream>(mesh_dir.append("boundary"));
-		  sprintf(casefiles, "%s/constant/polyMesh/owner.gz", casename.c_str()); 
-		  outfile_own = new ogzstream(casefiles);
-	  }
-	  else
-	  {
-		  sprintf(casefiles, "%s/constant/polyMesh/owner", casename.c_str()); 
-		  outfile_own = new ofstream(casefiles);
-	  }
-
-	  if(compressed)
-	  {
-		  sprintf(casefiles, "%s/constant/polyMesh/neighbour.gz", casename.c_str());
-		  outfile_nei = new ogzstream(casefiles);
-	  }
-	  else
-	  {
-		  sprintf(casefiles, "%s/constant/polyMesh/neighbour", casename.c_str());
-		  outfile_nei = new ofstream(casefiles);
-	  }
-
-	  // Note... the boundary file is not compressed
-      sprintf(casefiles, "%s/constant/polyMesh/boundary", casename.c_str()); 
-      outfile_bnd = new ofstream(casefiles);
 
       ResetTime();
 
@@ -731,8 +683,7 @@ namespace netgen
       if(outfile_own->good() && !error)
       {
          cout << "Writing the owner file: ";
-         WriteOwnerFile(outfile_own);
+         WriteOwnerFile(outfile_own.get());
-         delete outfile_own;
          cout << "Done! (Time Elapsed = " << GetTime() << " sec)\n";
       }
       else
@@ -746,8 +697,7 @@ namespace netgen
       if(outfile_nei->good() && !error)
       {
          cout << "Writing the neighbour file: ";
-         WriteNeighbourFile(outfile_nei);
+         WriteNeighbourFile(outfile_nei.get());
-         delete outfile_nei;
          cout << "Done! (Time Elapsed = " << GetTime() << " sec)\n";
       }
       else
@@ -761,8 +711,7 @@ namespace netgen
       if(outfile_faces->good() && !error)
       {
          cout << "Writing the faces file: ";
-         WriteFacesFile(outfile_faces, mesh);
+         WriteFacesFile(outfile_faces.get(), mesh);
-         delete outfile_faces;
          cout << "Done! (Time Elapsed = " << GetTime() << " sec)\n";
       }
       else
@@ -776,8 +725,7 @@ namespace netgen
       if(outfile_pnts->good() && !error)
       {
          cout << "Writing the points file: ";
-         WritePointsFile(outfile_pnts,mesh);
+         WritePointsFile(outfile_pnts.get(),mesh);
-         delete outfile_pnts;
          cout << "Done! (Time Elapsed = " << GetTime() << " sec)\n";
       }
       else
@@ -791,8 +739,7 @@ namespace netgen
       if(outfile_bnd->good() && !error)
       {
          cout << "Writing the boundary file: ";
-         WriteBoundaryFile(outfile_bnd);
+         WriteBoundaryFile(outfile_bnd.get());
-         delete outfile_bnd;
          cout << "Done! (Time Elapsed = " << GetTime() << " sec)\n";
       }
       else

libsrc/interface/writeabaqus.cpp

@@ -18,13 +18,13 @@ namespace netgen
 
 
 void WriteAbaqusFormat (const Mesh & mesh,
-			const string & filename)
+			const filesystem::path & filename)
 
 {
       
   cout << "\nWrite Abaqus Volume Mesh" << endl;
 
-  ofstream outfile (filename.c_str());
+  ofstream outfile (filename);
 
   outfile << "*Heading" << endl;
   outfile << " " << filename << endl;
@@ -124,16 +124,11 @@ void WriteAbaqusFormat (const Mesh & mesh,
       // periodic identification, implementation for
       // Helmut J. Boehm, TU Vienna
 	  
-      char cfilename[255];
+      auto mpcfilename = filename;
-      strcpy (cfilename, filename.c_str());
+      if (filename.extension() == ".inp")
-
+        mpcfilename.replace_extension(".mpc");
-      char mpcfilename[255];
-      strcpy (mpcfilename, cfilename);
-      size_t len = strlen (cfilename);
-      if (len >= 4 && (strcmp (mpcfilename+len-4, ".inp") == 0))
-	strcpy (mpcfilename+len-4, ".mpc");
       else
-	strcat (mpcfilename, ".mpc");
+        mpcfilename.concat(".mpc");
 	  
       ofstream mpc (mpcfilename);
 

libsrc/interface/writediffpack.cpp

@@ -21,12 +21,12 @@ namespace netgen
 
 void WriteDiffPackFormat (const Mesh & mesh,
 			  const NetgenGeometry & geom,
-			  const string & filename)
+			  const filesystem::path & filename)
 {
   //   double scale = globflags.GetNumFlag ("scale", 1);
   double scale = 1;
 
-  ofstream outfile(filename.c_str());
+  ofstream outfile(filename);
   outfile.precision(14);
 
 

libsrc/interface/writedolfin.cpp

@@ -19,7 +19,7 @@ namespace netgen
 
 
 
-  void WriteDolfinFormat (const Mesh & mesh, const string & filename)
+  void WriteDolfinFormat (const Mesh & mesh, const filesystem::path & filename)
   {
     cout << "start writing dolfin export" << endl;
 
@@ -30,7 +30,7 @@ namespace netgen
     // int invertsurf = mparam.inverttrigs;
     // int i, j;
 
-    ofstream outfile (filename.c_str());
+    ofstream outfile (filename);
 
     // char str[100];
     outfile.precision(8);

libsrc/interface/writeelmer.cpp

@@ -21,7 +21,7 @@ namespace netgen
 
 
 void WriteElmerFormat (const Mesh &mesh,
-                       const string &filename)
+                       const filesystem::path &dirname)
 {
   cout << "write elmer mesh files" << endl;
 
@@ -62,25 +62,17 @@ void WriteElmerFormat (const Mesh &mesh,
   int inverttets = mparam.inverttets;
   int invertsurf = mparam.inverttrigs;
 
-#ifdef WIN32
+  filesystem::create_directories(dirname);
-  char a[256];
-  sprintf( a, "mkdir %s", filename.c_str() );
-  system( a );
-#else
-  // int rc = 
-  mkdir(filename.c_str(), S_IRWXU|S_IRWXG);
-#endif
 
-  sprintf( str, "%s/mesh.header", filename.c_str() );
+  auto get_name = [&dirname]( string s ) {
-  ofstream outfile_h(str);
+      return filesystem::path(dirname).append(s);
-  sprintf( str, "%s/mesh.nodes", filename.c_str() );
+  };
-  ofstream outfile_n(str);
+
-  sprintf( str, "%s/mesh.elements", filename.c_str() );
+  ofstream outfile_h(get_name("mesh.header"));
-  ofstream outfile_e(str);
+  ofstream outfile_n(get_name("mesh.nodes"));
-  sprintf( str, "%s/mesh.boundary", filename.c_str() );
+  ofstream outfile_e(get_name("mesh.elements"));
-  ofstream outfile_b(str);
+  ofstream outfile_b(get_name("mesh.boundary"));
-  sprintf( str, "%s/mesh.names", filename.c_str() );
+  ofstream outfile_names(get_name("mesh.names"));
-  ofstream outfile_names(str);
 
   for( auto codim : IntRange(0, mesh.GetDimension()-1) )
   {

libsrc/interface/writefeap.cpp

@@ -22,7 +22,7 @@ namespace netgen
 
 
 void WriteFEAPFormat (const Mesh & mesh,
-		      const string & filename)
+		      const filesystem::path & filename)
   
 {
   // Feap format by A. Rieger 
@@ -35,7 +35,7 @@ void WriteFEAPFormat (const Mesh & mesh,
 
   double scale = 1;   // globflags.GetNumFlag ("scale", 1);
   
-  ofstream outfile(filename.c_str());
+  ofstream outfile(filename);
  
   outfile << "feap" << "\n";
   outfile << mesh.GetNP();

libsrc/interface/writefluent.cpp

@@ -18,7 +18,7 @@ namespace netgen
 
 
 void WriteFluentFormat (const Mesh & mesh,
-			const string & filename)
+			const filesystem::path & filename)
 
 {
   cout << "start writing fluent export" << endl;
@@ -28,7 +28,7 @@ void WriteFluentFormat (const Mesh & mesh,
   int nse = mesh.GetNSE();
   int i, j;
 
-  ofstream outfile (filename.c_str());
+  ofstream outfile (filename);
   char str[100];
 
   outfile.precision(6);

libsrc/interface/writegmsh.cpp

@@ -32,9 +32,9 @@ namespace netgen
 
 void WriteGmshFormat (const Mesh & mesh,
                       const NetgenGeometry & geom,
-                      const string & filename)
+                      const filesystem::path & filename)
 {
-  ofstream outfile (filename.c_str());
+  ofstream outfile (filename);
   outfile.precision(6);
   outfile.setf (ios::fixed, ios::floatfield);
   outfile.setf (ios::showpoint);

libsrc/interface/writegmsh2.cpp

@@ -49,9 +49,9 @@ namespace netgen
    */
    void WriteGmsh2Format (const Mesh & mesh,
       const NetgenGeometry & geom,
-      const string & filename)
+      const filesystem::path & filename)
    {
-      ofstream outfile (filename.c_str());
+      ofstream outfile (filename);
       outfile.precision(6);
       outfile.setf (ios::fixed, ios::floatfield);
       outfile.setf (ios::showpoint);

libsrc/interface/writejcm.cpp

@@ -17,7 +17,7 @@ namespace netgen
 
 void WriteJCMFormat (const Mesh & mesh,
                      const NetgenGeometry & geom,
-                     const string & filename)
+                     const filesystem::path & filename)
 {
   if (mesh.GetDimension() != 3)
   {
@@ -122,7 +122,7 @@ void WriteJCMFormat (const Mesh & mesh,
       nbquad++;
   }
   
-  ofstream outfile (filename.c_str());
+  ofstream outfile (filename);
   outfile.precision(6);
   outfile.setf (ios::fixed, ios::floatfield);
   outfile.setf (ios::showpoint);

libsrc/interface/writepermas.cpp

@@ -22,18 +22,18 @@ namespace netgen
 
 
     // This should be the new function to export a PERMAS file
-    void WritePermasFormat (const Mesh &mesh, const string &filename, 
+    void WritePermasFormat (const Mesh &mesh, const filesystem::path &filename, 
                             string &strComp, string &strSitu) 
     {
-        ofstream outfile (filename.c_str());
+        ofstream outfile (filename);
         addComponent(strComp, strSitu, outfile);
         WritePermasFormat ( mesh, filename);
     }
 
-    void WritePermasFormat (const Mesh &mesh, const string &filename)
+    void WritePermasFormat (const Mesh &mesh, const filesystem::path &filename)
     {
         string strComp, strSitu;
-        ofstream outfile (filename.c_str());
+        ofstream outfile (filename);
         
         outfile.precision(8);
 

libsrc/interface/writetecplot.cpp

@@ -28,7 +28,7 @@ void WriteTecPlotFormat (const Mesh & mesh,
   INDEX nse = mesh.GetNSE();
   
   NgArray<int> sn(np);
-  ofstream outfile(filename.c_str());
+  ofstream outfile(filename);
   
   outfile << "TITLE=\" " << filename << "\"" << endl;
 

libsrc/interface/writetet.cpp

@@ -272,7 +272,7 @@ namespace netgen
 
 
 
-    ofstream outfile(filename.c_str());
+    ofstream outfile(filename);
 
     outfile.precision(16);
 

libsrc/interface/writetochnog.cpp

@@ -20,11 +20,11 @@ namespace netgen
 
 
 void WriteTochnogFormat (const Mesh & mesh,
-			 const string & filename)
+			 const filesystem::path & filename)
 {
   cout << "\nWrite Tochnog Volume Mesh" << endl;
 
-  ofstream outfile (filename.c_str());
+  ofstream outfile (filename);
 
   outfile << "(Nodes and Elements generated with NETGEN" << endl;
   outfile << " " << filename << ")" << endl;

libsrc/interface/writeuser.cpp

@@ -58,9 +58,9 @@ namespace netgen
   
 
 
-bool WriteUserFormat (const string & format,
+bool WriteUserFormat (const filesystem::path & format,
 		      const Mesh & mesh,
-		      const string & filename)
+		      const filesystem::path & filename)
 {
   // cout << "write user &hgeom = " << &hgeom << endl;
   // const CSGeometry & geom = *dynamic_cast<const CSGeometry*> (&hgeom);
@@ -167,7 +167,7 @@ bool WriteUserFormat (const string & format,
 
 void WriteNeutralFormat (const Mesh & mesh,
 			 const NetgenGeometry & geom,
-			 const string & filename)
+			 const filesystem::path & filename)
 {
   cout << "write neutral, new" << endl;
   int np = mesh.GetNP();
@@ -179,7 +179,7 @@ void WriteNeutralFormat (const Mesh & mesh,
   int inverttets = mparam.inverttets;
   int invertsurf = mparam.inverttrigs;
 
-  ofstream outfile (filename.c_str());
+  ofstream outfile (filename);
 
   outfile.precision(6);
   outfile.setf (ios::fixed, ios::floatfield);
@@ -283,14 +283,14 @@ void WriteNeutralFormat (const Mesh & mesh,
 
 
 void WriteSurfaceFormat (const Mesh & mesh,
-			 const string & filename)
+			 const filesystem::path & filename)
 {
   // surface mesh
   int i, j;
 
   cout << "Write Surface Mesh" << endl;
 
-  ofstream outfile (filename.c_str());
+  ofstream outfile (filename);
 
   outfile << "surfacemesh" << endl;
 
@@ -325,16 +325,17 @@ void WriteSurfaceFormat (const Mesh & mesh,
  */
 
 void WriteSTLFormat (const Mesh & mesh,
-		     const string & filename)
+		     const filesystem::path & filename)
 {
   cout << "\nWrite STL Surface Mesh" << endl;
 
+  auto ext = filename.extension();
   ostream *outfile;
 
-  if(filename.substr(filename.length()-3,3) == ".gz")
+  if(ext == ".gz")
-	  outfile = new ogzstream(filename.c_str());
+	  outfile = new ogzstream(filename);
   else
-	  outfile = new ofstream(filename.c_str());
+	  outfile = new ofstream(filename);
 
   int i;
 
@@ -382,16 +383,17 @@ void WriteSTLFormat (const Mesh & mesh,
  *    when using a third-party mesher
  */
 void WriteSTLExtFormat (const Mesh & mesh,
-		     const string & filename)
+		     const filesystem::path & filename)
 {
   cout << "\nWrite STL Surface Mesh (with separated boundary faces)" << endl;
 
+  auto ext = filename.extension();
   ostream *outfile;
 
-  if(filename.substr(filename.length()-3,3) == ".gz")
+  if(ext == ".gz")
-	  outfile = new ogzstream(filename.c_str());
+	  outfile = new ogzstream(filename);
   else
-	  outfile = new ofstream(filename.c_str());
+	  outfile = new ofstream(filename);
 
   outfile->precision(10);
 
@@ -474,7 +476,7 @@ void WriteSTLExtFormat (const Mesh & mesh,
 
 void WriteVRMLFormat (const Mesh & mesh,
 		      bool faces,
-		      const string & filename)
+		      const filesystem::path & filename)
 {
 
   if (faces)
@@ -487,7 +489,7 @@ void WriteVRMLFormat (const Mesh & mesh,
       int nse = mesh.GetNSE();
       int i, j;
 
-      ofstream outfile (filename.c_str());
+      ofstream outfile (filename);
 
       outfile.precision(6);
       outfile.setf (ios::fixed, ios::floatfield);
@@ -563,7 +565,7 @@ void WriteVRMLFormat (const Mesh & mesh,
       int nse = mesh.GetNSE();
       int i, j;
 
-      ofstream outfile (filename.c_str());
+      ofstream outfile (filename);
 
       outfile.precision(6);
       outfile.setf (ios::fixed, ios::floatfield);
@@ -639,10 +641,10 @@ void WriteVRMLFormat (const Mesh & mesh,
  */
 void WriteFEPPFormat (const Mesh & mesh,
 		      const NetgenGeometry & geom,
-		      const string & filename)
+		      const filesystem::path & filename)
 {
 
-  ofstream outfile (filename.c_str());
+  ofstream outfile (filename);
 
   if (mesh.GetDimension() == 3)
 
@@ -770,7 +772,7 @@ void WriteFEPPFormat (const Mesh & mesh,
 
 void WriteEdgeElementFormat (const Mesh & mesh,
 			     const NetgenGeometry & geom,
-			     const string & filename)
+			     const filesystem::path & filename)
 {
   cout << "write edge element format" << endl;
 
@@ -785,7 +787,7 @@ void WriteEdgeElementFormat (const Mesh & mesh,
   int invertsurf = mparam.inverttrigs;
   NgArray<int> edges;
 
-  ofstream outfile (filename.c_str());
+  ofstream outfile (filename);
 
   outfile.precision(6);
   outfile.setf (ios::fixed, ios::floatfield);
@@ -908,8 +910,8 @@ void WriteEdgeElementFormat (const Mesh & mesh,
 void WriteFile (int typ,
 		const Mesh & mesh,
 		const CSGeometry & geom,
-		const char * filename,
+		const filesystem::path & filename,
-		const char * geomfile,
+		const filesystem::path & geomfile,
 		double h)
 {
 

libsrc/interface/writeuser.hpp

@@ -13,15 +13,15 @@ DLL_HEADER extern
 void WriteFile (int typ,
                 const Mesh & mesh,
                 const NetgenGeometry & geom,
-                const char * filename,
+                const filesystem::path & filename,
-                const char * geomfile = NULL,
+                const filesystem::path & geomfile = "", 
                 double h = 0);
 
 
 
 DLL_HEADER extern
 void ReadFile (Mesh & mesh,
-               const string & filename);
+               const filesystem::path & filename);
 
 
 
@@ -31,15 +31,15 @@ void ReadFile (Mesh & mesh,
 extern
 void WriteNeutralFormat (const Mesh & mesh,
                          const NetgenGeometry & geom,
-                         const string & filename);
+                         const filesystem::path & filename);
 
 extern
 void WriteSurfaceFormat (const Mesh & mesh,
-                         const string & filename);
+                         const filesystem::path & filename);
 
 extern
 void WriteSTLFormat (const Mesh & mesh,
-                     const string & filename);
+                     const filesystem::path & filename);
 
 
 // Philippose - 16 August 2010
@@ -48,134 +48,134 @@ void WriteSTLFormat (const Mesh & mesh,
 // a separate "solid" entity in the STL file
 extern
 void WriteSTLExtFormat (const Mesh & mesh,
-                        const string & filename);
+                        const filesystem::path & filename);
 
 
 extern
 void WriteVRMLFormat (const Mesh & mesh,
                       bool faces,
-                      const string & filename);
+                      const filesystem::path & filename);
 
 extern
 void WriteFEPPFormat (const Mesh & mesh,
                       const NetgenGeometry & geom,
-                      const string & filename);
+                      const filesystem::path & filename);
 
 extern
 void WriteGmshFormat (const Mesh & mesh,
                       const NetgenGeometry & geom,
-                      const string & filename);
+                      const filesystem::path & filename);
 
 
 // Philippose - 29/01/2009
 // Added GMSH v2.xx Mesh Export support
 void WriteGmsh2Format (const Mesh & mesh,
                        const NetgenGeometry & geom,
-                       const string & filename);
+                       const filesystem::path & filename);
 
 
 // Philippose - 25/10/2009
 // Added OpenFOAM 1.5+ Mesh Export support
 extern 
 void WriteOpenFOAM15xFormat (const Mesh & mesh, 
-                             const string & casename,
+                             const filesystem::path & casename,
                              const bool compressed);
 
 
 extern
 void WriteUserChemnitz (const Mesh & mesh,
-                        const string & filename);
+                        const filesystem::path & filename);
 
 extern
 void WriteJCMFormat (const Mesh & mesh,
                      const NetgenGeometry & geom,
-                     const string & filename);
+                     const filesystem::path & filename);
 
 
 extern
 void WriteDiffPackFormat (const Mesh & mesh,
                           const NetgenGeometry & geom,
-                          const string & filename);
+                          const filesystem::path & filename);
 
 extern
 void WriteTochnogFormat (const Mesh & mesh,
-                         const string & filename);
+                         const filesystem::path & filename);
 
 extern
 void WriteTecPlotFormat (const Mesh & mesh,
                          const NetgenGeometry & geom,
-                         const string & filename);
+                         const filesystem::path & filename);
 
 extern
 void WriteAbaqusFormat (const Mesh & mesh,
-                        const string & filename);
+                        const filesystem::path & filename);
 
 extern
 void WriteFluentFormat (const Mesh & mesh,
-                        const string & filename);
+                        const filesystem::path & filename);
 
 extern
 void WritePermasFormat (const Mesh & mesh,
-                        const string & filename);
+                        const filesystem::path & filename);
 
 extern
 void WriteFEAPFormat (const Mesh & mesh,
-                      const string & filename);
+                      const filesystem::path & filename);
 
 extern
 void WriteElmerFormat (const Mesh & mesh,
-                       const string & filename);
+                       const filesystem::path & filename);
 
 
 extern
 void WriteEdgeElementFormat (const Mesh & mesh,
                              const NetgenGeometry & geom,
-                             const string & filename);
+                             const filesystem::path & filename);
 
 
 
 #ifdef OLIVER
 extern
 void WriteTETFormat (const Mesh & mesh,
-                     const string & filename);
+                     const filesystem::path & filename);
 
 #endif
 
 extern void ReadTETFormat (Mesh & mesh,
-                           const string & filename);
+                           const filesystem::path & filename);
 
 
 extern void ReadFNFFormat (Mesh & mesh,
-                           const string & filename);
+                           const filesystem::path & filename);
 
 
 
 extern void DLL_HEADER ReadCGNSMesh (Mesh & mesh,
-                           const string & filename);
+                           const filesystem::path & filename);
 
 extern void DLL_HEADER WriteCGNSMesh (const Mesh & mesh,
-                           const string & filename);
+                           const filesystem::path & filename);
 
 // read/write mesh and solutions from CGNS file
 extern tuple<shared_ptr<Mesh>, vector<string>, vector<Array<double>>, vector<int>>
-DLL_HEADER ReadCGNSFile(string filename, int base);
+DLL_HEADER ReadCGNSFile(const filesystem::path & filename, int base);
 
-extern void DLL_HEADER WriteCGNSFile(shared_ptr<Mesh> mesh,string filename, vector<string> fields,
+extern void DLL_HEADER WriteCGNSFile(shared_ptr<Mesh> mesh, const filesystem::path & filename, vector<string> fields,
                                 vector<Array<double>> values, vector<int> locations);
 
 
 void WriteDolfinFormat (const Mesh & mesh,
-                        const string & filename);
+                        const filesystem::path & filename);
 
 
 extern void DLL_HEADER RegisterUserFormats (NgArray<const char*> & names,
                                  NgArray<const char*> & extensions);
 
 
-extern bool DLL_HEADER WriteUserFormat (const string & format,
+extern bool DLL_HEADER WriteUserFormat (const filesystem::path & format,
                                         const Mesh & mesh,
                                         // const NetgenGeometry & geom,
-                                        const string & filename);
+                                        const filesystem::path & filename);
 
 }
 

libsrc/interface/wuchemnitz.cpp

@@ -306,9 +306,9 @@ namespace netgen
     
 
   void WriteUserChemnitz (const Mesh & mesh,
-                          const string & filename)
+                          const filesystem::path & filename)
   {
-    ofstream outfile (filename.c_str());
+    ofstream outfile (filename);
 
     ReadFileMesh (mesh);
     Convert ();

libsrc/meshing/basegeom.cpp

@@ -1124,7 +1124,7 @@ namespace netgen
     return 0;
   }
 
-  void NetgenGeometry :: Save (string filename) const
+  void NetgenGeometry :: Save (const filesystem::path & filename) const
   {
     throw NgException("Cannot save geometry - no geometry available");
   }

libsrc/meshing/basegeom.hpp

@@ -7,7 +7,6 @@
 /* Date:   23. Aug. 09                                                    */
 /**************************************************************************/
 
-
 struct Tcl_Interp;
 
 namespace netgen
@@ -298,7 +297,7 @@ namespace netgen
           return i;
       throw Exception("Couldn't find edge index");
     }
-    virtual void Save (string filename) const;
+    virtual void Save (const filesystem::path & filename) const;
     virtual void SaveToMeshFile (ostream & /* ost */) const { ; }
   };
 
@@ -310,7 +309,7 @@ namespace netgen
   {
   public:
     virtual ~GeometryRegister();
-    virtual NetgenGeometry * Load (string filename) const = 0;
+    virtual NetgenGeometry * Load (const filesystem::path & filename) const = 0;
     virtual NetgenGeometry * LoadFromMeshFile (istream & /* ist */, string) const { return NULL; }
     virtual class VisualScene * GetVisualScene (const NetgenGeometry * /* geom */) const
     { return NULL; }

libsrc/meshing/meshclass.cpp

@@ -627,9 +627,12 @@ namespace netgen
 
 
 
-  void Mesh :: Save (const string & filename) const
+  void Mesh :: Save (const filesystem::path & filename) const
   {
-    if (filename.find(".vol.bin") != string::npos)
+    string ext0 = filename.stem().extension().string();
+    string ext = filename.extension().string();
+
+    if (ext0 == ".vol" && ext == ".bin")
     {
         BinaryOutArchive in(filename);
         in & const_cast<Mesh&>(*this);
@@ -637,12 +640,12 @@ namespace netgen
     }
 
     ostream * outfile;
-    if (filename.find(".vol.gz")!=string::npos)
+    if (ext0 == ".vol" && ext == ".gz")
-      outfile = new ogzstream(filename.c_str());
+      outfile = new ogzstream(filename);
-    else if (filename.find(".vol")!=string::npos)
+    else if (ext == ".vol")
-      outfile = new ofstream(filename.c_str());
+      outfile = new ofstream(filename);
     else
-      outfile = new ogzstream((filename+".vol.gz").c_str());
+      outfile = new ogzstream(filesystem::path(filename).concat(".vol.gz"));
 
     Save(*outfile);
     delete outfile;
@@ -1109,11 +1112,14 @@ namespace netgen
 
 
 
-  void Mesh :: Load (const string & filename)
+  void Mesh :: Load (const filesystem::path & filename)
   {
-    cout << "filename = " << filename << endl;
+    PrintMessage (1, "filename = ", filename);
 
-    if (filename.find(".vol.bin") != string::npos)
+    string ext0 = filename.stem().extension().string();
+    string ext = filename.extension().string();
+
+    if (ext0 == ".vol" && ext == ".bin")
     {
         BinaryInArchive in(filename);
         in & (*this);
@@ -1122,12 +1128,11 @@ namespace netgen
 
     istream * infile = NULL;
 
-    if (filename.find(".vol.gz") != string::npos)
+    if (ext0 == ".vol" && ext == ".gz")
-      infile = new igzstream (filename.c_str());
+      infile = new igzstream (filename);
     else
-      infile = new ifstream (filename.c_str());
+      infile = new ifstream (filename);
 
-    // ifstream infile(filename.c_str());
     if (! (infile -> good()) )
       throw NgException ("mesh file not found");
 
@@ -1651,6 +1656,10 @@ namespace netgen
 	clusters -> Update();
       }
 
+    auto geo = geometryregister.LoadFromMeshFile (infile);
+    if(geo)
+       geometry = geo;
+
     SetNextMajorTimeStamp();
     //  PrintMemInfo (cout);
   }
@@ -1840,9 +1849,9 @@ namespace netgen
   }
 
 
-  void Mesh :: Merge (const string & filename, const int surfindex_offset)
+  void Mesh :: Merge (const filesystem::path & filename, const int surfindex_offset)
   {
-    ifstream infile(filename.c_str());
+    ifstream infile(filename);
     if (!infile.good())
       throw NgException ("mesh file not found");
 
@@ -3758,7 +3767,7 @@ namespace netgen
   }
 
 
-  void Mesh :: LoadLocalMeshSize (const string &  meshsizefilename)
+  void Mesh :: LoadLocalMeshSize (const filesystem::path &  meshsizefilename)
   {
     // Philippose - 10/03/2009
     // Improve error checking when loading and reading
@@ -3766,7 +3775,7 @@ namespace netgen
 
     if (meshsizefilename.empty()) return;
 
-    ifstream msf(meshsizefilename.c_str());
+    ifstream msf(meshsizefilename);
 
     // Philippose - 09/03/2009
     // Adding print message information in case the specified 

libsrc/meshing/meshclass.hpp

@@ -11,8 +11,12 @@
   The mesh class
 */
 
+#include<filesystem>
+
 namespace netgen
 {
+  using namespace std;
+
   enum resthtype { RESTRICTH_FACE, RESTRICTH_EDGE, 
 		   RESTRICTH_SURFACEELEMENT, RESTRICTH_POINT, RESTRICTH_SEGMENT };
 
@@ -446,7 +450,7 @@ namespace netgen
     ///
     DLL_HEADER void RestrictLocalH (resthtype rht, int nr, double loch);
     ///
-    DLL_HEADER void LoadLocalMeshSize (const string & meshsizefilename);
+    DLL_HEADER void LoadLocalMeshSize (const filesystem::path & meshsizefilename);
     ///
     DLL_HEADER void SetGlobalH (double h);
     ///
@@ -545,11 +549,11 @@ namespace netgen
     ///
 	DLL_HEADER void Merge (istream & infile, const int surfindex_offset = 0);
     ///
-	DLL_HEADER void Save (const string & filename) const;
+	DLL_HEADER void Save (const filesystem::path & filename) const;
     ///
-	DLL_HEADER void Load (const string & filename);
+	DLL_HEADER void Load (const filesystem::path & filename);
     ///
-	DLL_HEADER void Merge (const string & filename, const int surfindex_offset = 0);
+	DLL_HEADER void Merge (const filesystem::path & filename, const int surfindex_offset = 0);
 
 
     DLL_HEADER void DoArchive (Archive & archive);

libsrc/meshing/python_mesh.cpp

@@ -813,8 +813,7 @@ DLL_HEADER void ExportNetgenMeshing(py::module &m)
 	    if(geo!=nullptr) mesh->SetGeometry(geo);
 	    else if(ng_geometry!=nullptr) mesh->SetGeometry(ng_geometry);
 	  }),py::call_guard<py::gil_scoped_release>())
-    // static_cast<void(Mesh::*)(const string & name)>(&Mesh::Load))
+    .def("Save", static_cast<void(Mesh::*)(const filesystem::path & name)const>(&Mesh::Save),py::call_guard<py::gil_scoped_release>())
-    .def("Save", static_cast<void(Mesh::*)(const string & name)const>(&Mesh::Save),py::call_guard<py::gil_scoped_release>())
     .def("Export",
          [] (Mesh & self, string filename, string format)
           {

libsrc/occ/occgeom.cpp

@@ -68,7 +68,7 @@
 
 namespace netgen
 {
-  void LoadOCCInto(OCCGeometry* occgeo, const char* filename);
+  void LoadOCCInto(OCCGeometry* occgeo, const filesystem::path & filename);
   void PrintContents (OCCGeometry * geom);
 
   std::map<Handle(TopoDS_TShape), ShapeProperties> OCCGeometry::global_shape_properties;
@@ -140,10 +140,10 @@ namespace netgen
     if(copy)
       {
         auto filename = GetTempFilename();
-        step_utils::WriteSTEP(_shape, filename.c_str());
+        step_utils::WriteSTEP(_shape, filename);
-        LoadOCCInto(this, filename.c_str());
+        LoadOCCInto(this, filename);
         dimension = aoccdim;
-        std::remove(filename.c_str());
+        filesystem::remove(filename);
       }
     else
       {
@@ -1347,7 +1347,7 @@ namespace netgen
 //    }
 
 
-  void LoadOCCInto(OCCGeometry* occgeo, const char* filename)
+  void LoadOCCInto(OCCGeometry* occgeo, const filesystem::path & filename)
   {
       static Timer timer_all("LoadOCC"); RegionTimer rtall(timer_all);
       static Timer timer_readfile("LoadOCC-ReadFile");
@@ -1375,7 +1375,7 @@ namespace netgen
       // Enable transfer of colours
       reader.SetColorMode(Standard_True);
       reader.SetNameMode(Standard_True);
-      Standard_Integer stat = reader.ReadFile((char*)filename);
+      Standard_Integer stat = reader.ReadFile(filename.string().c_str());
       timer_readfile.Stop();
 
       timer_transfer.Start();
@@ -1411,7 +1411,7 @@ namespace netgen
    to extract individual surface colours via the extended
    OpenCascade XDE and XCAF Feature set.
    */
-   OCCGeometry *LoadOCC_IGES(const char *filename)
+   OCCGeometry *LoadOCC_IGES(const filesystem::path & filename)
    {
       OCCGeometry *occgeo;
       occgeo = new OCCGeometry;
@@ -1432,7 +1432,7 @@ namespace netgen
 
       IGESCAFControl_Reader reader;
 
-      Standard_Integer stat = reader.ReadFile((char*)filename);
+      Standard_Integer stat = reader.ReadFile(filename.string().c_str());
 
       if(stat != IFSelect_RetDone)
       {
@@ -1485,7 +1485,7 @@ namespace netgen
    to extract individual surface colours via the extended
    OpenCascade XDE and XCAF Feature set.
    */
-   OCCGeometry * LoadOCC_STEP (const char * filename)
+   OCCGeometry * LoadOCC_STEP (const filesystem::path & filename)
    {
       OCCGeometry * occgeo;
       occgeo = new OCCGeometry;
@@ -1497,13 +1497,13 @@ namespace netgen
 
 
 
-   OCCGeometry *LoadOCC_BREP (const char *filename)
+   OCCGeometry *LoadOCC_BREP (const filesystem::path & filename)
    {
       OCCGeometry * occgeo;
       occgeo = new OCCGeometry;
 
       BRep_Builder aBuilder;
-      Standard_Boolean result = BRepTools::Read(occgeo->shape, const_cast<char*> (filename),aBuilder);
+      Standard_Boolean result = BRepTools::Read(occgeo->shape, filename.string().c_str(), aBuilder);
 
       if(!result)
       {
@@ -1521,34 +1521,36 @@ namespace netgen
    }
 
 
-  void OCCGeometry :: Save (string sfilename) const
+  void OCCGeometry :: Save (const filesystem::path & filename) const
   {
-    const char * filename = sfilename.c_str();
+    string ext = ToLower(filename.extension());
-    if (strlen(filename) < 4) 
+    auto s_filename = filename.string();
-      throw NgException ("illegal filename");
+    auto c_filename = s_filename.c_str();
 
-    if (strcmp (&filename[strlen(filename)-3], "igs") == 0)
+    if (ext == ".igs")
       {
 	IGESControl_Writer writer("millimeters", 1);
 	writer.AddShape (shape);
-	writer.Write (filename);
+	writer.Write (c_filename);
       }
-    else if (strcmp (&filename[strlen(filename)-3], "stp") == 0)
+    else if (ext == ".stp")
       {
           step_utils::WriteSTEP(*this, filename);
       }
-    else if (strcmp (&filename[strlen(filename)-3], "stl") == 0)
+    else if (ext == ".stl")
       {
 	StlAPI_Writer writer;
 	writer.ASCIIMode() = Standard_True;
-	writer.Write (shape, filename);
+	writer.Write (shape, c_filename);
       }
-    else if (strcmp (&filename[strlen(filename)-4], "stlb") == 0)
+    else if (ext == ".stlb")
       {
 	StlAPI_Writer writer;
 	writer.ASCIIMode() = Standard_False;
-	writer.Write (shape, filename);
+	writer.Write (shape, c_filename);
       }
+
+    throw NgException ("Unkown target format: " + filename);
   }
 
   void OCCGeometry :: SaveToMeshFile (ostream & ost) const
@@ -2267,7 +2269,7 @@ namespace netgen
           OCCGeometry::identifications[shape_origin.TShape()] = result;
       }
 
-      void WriteSTEP(const TopoDS_Shape & shape, string filename)
+      void WriteSTEP(const TopoDS_Shape & shape, const filesystem::path & filename)
       {
           Interface_Static::SetCVal("write.step.schema", "AP242IS");
           Interface_Static::SetIVal("write.step.assembly",1);
@@ -2303,7 +2305,7 @@ namespace netgen
             for (TopExp_Explorer e(shape, typ); e.More(); e.Next())
                 WriteProperties(model, finder, e.Current());
 
-          writer.Write(filename.c_str());
+          writer.Write(filename.string().c_str());
       }
 
   } // namespace step_utils

libsrc/occ/occgeom.hpp

@@ -196,7 +196,7 @@ namespace netgen
                      int nr, FlatArray<int, PointIndex> glob2loc) const override;
     // void OptimizeSurface(Mesh& mesh, const MeshingParameters& mparam) const override {}
  
-    void Save (string filename) const override;
+    void Save (const filesystem::path & filename) const override;
     void SaveToMeshFile (ostream & /* ost */) const override;
      
     void DoArchive(Archive& ar) override;
@@ -356,9 +356,9 @@ namespace netgen
 
   void PrintContents (OCCGeometry * geom);
 
-  DLL_HEADER OCCGeometry * LoadOCC_IGES (const char * filename);
+  DLL_HEADER OCCGeometry * LoadOCC_IGES (const filesystem::path & filename);
-  DLL_HEADER OCCGeometry * LoadOCC_STEP (const char * filename);
+  DLL_HEADER OCCGeometry * LoadOCC_STEP (const filesystem::path & filename);
-  DLL_HEADER OCCGeometry * LoadOCC_BREP (const char * filename);
+  DLL_HEADER OCCGeometry * LoadOCC_BREP (const filesystem::path & filename);
 
   // Philippose - 31.09.2009
   // External access to the mesh generation functions within the OCC
@@ -535,9 +535,9 @@ namespace netgen
                           const Handle(TDocStd_Document) step_doc);
       void WriteProperties(const Handle(Interface_InterfaceModel) model, const Handle(Transfer_FinderProcess) finder, const TopoDS_Shape & shape);
 
-      void WriteSTEP(const TopoDS_Shape & shape, string filename);
+      void WriteSTEP(const TopoDS_Shape & shape, const filesystem::path & filename);
 
-      inline void WriteSTEP(const OCCGeometry & geo, string filename)
+      inline void WriteSTEP(const OCCGeometry & geo, const filesystem::path & filename)
       {
           WriteSTEP(geo.GetShape(), filename);
       }

libsrc/occ/occpkg.cpp

@@ -43,7 +43,7 @@ namespace netgen
   class OCCGeometryRegister : public GeometryRegister
   {
   public:
-    virtual NetgenGeometry * Load (string filename) const;
+    virtual NetgenGeometry * Load (const filesystem::path & filename) const;
     virtual VisualScene * GetVisualScene (const NetgenGeometry * geom) const;
 
     virtual void SetParameters (Tcl_Interp * interp) 
@@ -893,55 +893,27 @@ namespace netgen
 
 
 
-  NetgenGeometry *  OCCGeometryRegister :: Load (string filename) const
+  NetgenGeometry *  OCCGeometryRegister :: Load (const filesystem::path & filename) const
   {
-    const char * lgfilename = filename.c_str();
+    string ext = ToLower(filename.extension());
 
-
+    if (ext == ".iges" || ext == ".igs")
-    /*
-    if (strcmp (&cfilename[strlen(cfilename)-3], "geo") == 0)
       {
-	PrintMessage (1, "Load OCCG geometry file ", cfilename);
+	PrintMessage (1, "Load IGES geometry file ", filename);
-	
+	OCCGeometry * occgeometry = LoadOCC_IGES (filename);
-	extern OCCGeometry * ParseOCCG (istream & istr);
-
-	ifstream infile(cfilename);
-
-	OCCGeometry * hgeom = ParseOCCG (infile);
-	if (!hgeom)
-	  throw NgException ("geo-file should start with 'algebraic3d'");
-
-	hgeom -> FindIdenticSurfaces(1e-8 * hgeom->MaxSize()); 
-	return hgeom;
-      }
-    */
-
-
-    if ((strcmp (&lgfilename[strlen(lgfilename)-4], "iges") == 0) ||
-	(strcmp (&lgfilename[strlen(lgfilename)-3], "igs") == 0) ||
-	(strcmp (&lgfilename[strlen(lgfilename)-3], "IGS") == 0) ||
-	(strcmp (&lgfilename[strlen(lgfilename)-4], "IGES") == 0))
-      {
-	PrintMessage (1, "Load IGES geometry file ", lgfilename);
-	OCCGeometry * occgeometry = LoadOCC_IGES (lgfilename);
 	return occgeometry;
       }
 
-    else if ((strcmp (&lgfilename[strlen(lgfilename)-4], "step") == 0) ||
+    else if (ext == ".stp" || ext == ".step")
-		     (strcmp (&lgfilename[strlen(lgfilename)-3], "stp") == 0) ||
-		     (strcmp (&lgfilename[strlen(lgfilename)-3], "STP") == 0) ||
-		     (strcmp (&lgfilename[strlen(lgfilename)-4], "STEP") == 0))
       {
-	PrintMessage (1, "Load STEP geometry file ", lgfilename);
+	PrintMessage (1, "Load STEP geometry file ", filename);
-	OCCGeometry * occgeometry = LoadOCC_STEP (lgfilename);
+	OCCGeometry * occgeometry = LoadOCC_STEP (filename);
 	return occgeometry;    
       }
-    else if ((strcmp (&lgfilename[strlen(lgfilename)-4], "brep") == 0) ||
+    else if (ext == ".brep")
-	     (strcmp (&lgfilename[strlen(lgfilename)-4], "Brep") == 0) ||
-	     (strcmp (&lgfilename[strlen(lgfilename)-4], "BREP") == 0))
       {
-	PrintMessage (1, "Load BREP geometry file ", lgfilename);
+	PrintMessage (1, "Load BREP geometry file ", filename);
-	OCCGeometry * occgeometry = LoadOCC_BREP (lgfilename);
+	OCCGeometry * occgeometry = LoadOCC_BREP (filename);
 	return occgeometry;
       }
     

libsrc/occ/python_occ.cpp

@@ -137,11 +137,11 @@ DLL_HEADER void ExportNgOCC(py::module &m)
                   {
                     shared_ptr<OCCGeometry> geo;
                     if(EndsWith(filename, ".step") || EndsWith(filename, ".stp"))
-                      geo.reset(LoadOCC_STEP(filename.c_str()));
+                      geo.reset(LoadOCC_STEP(filename));
                     else if(EndsWith(filename, ".brep"))
-                      geo.reset(LoadOCC_BREP(filename.c_str()));
+                      geo.reset(LoadOCC_BREP(filename));
                     else if(EndsWith(filename, ".iges"))
-                      geo.reset(LoadOCC_IGES(filename.c_str()));
+                      geo.reset(LoadOCC_IGES(filename));
                     else
                       throw Exception("Cannot load file " + filename + "\nValid formats are: step, stp, brep, iges");
                     ng_geometry = geo;
@@ -279,7 +279,7 @@ DLL_HEADER void ExportNgOCC(py::module &m)
 
   
   
-  m.def("LoadOCCGeometry",[] (const string & filename)
+  m.def("LoadOCCGeometry",[] (filesystem::path filename)
         {
           cout << "WARNING: LoadOCCGeometry is deprecated! Just use the OCCGeometry(filename) constructor. It is able to read brep and iges files as well!" << endl;
           ifstream ist(filename);

libsrc/stlgeom/stlgeom.cpp

@@ -68,28 +68,27 @@ STLGeometry :: ~STLGeometry()
   // delete edgedata;
 }
 
-void STLGeometry :: Save (string filename) const
+void STLGeometry :: Save (const filesystem::path & filename) const
 {
-  const char  * cfilename = filename.c_str();
+  string ext = ToLower(filename.extension());
-  if (strlen(cfilename) < 4) 
-    throw NgException ("illegal filename");
 
-  if (strlen(cfilename) > 3 &&
+  if (ext == ".stl")
-      strcmp (&cfilename[strlen(cfilename)-3], "stl") == 0)
     {
-      STLTopology::Save (cfilename);
+      STLTopology::Save (filename);
+      return;
     }
-  else if (strlen(cfilename) > 4 &&
+  else if (ext == ".stlb")
-	   strcmp (&cfilename[strlen(cfilename)-4], "stlb") == 0)
     {
-      SaveBinary (cfilename,"Binary STL Geometry");
+      SaveBinary (filename,"Binary STL Geometry");
+      return;
+    }
+  else if (ext == ".stle")
+    {
+      SaveSTLE (filename);
+      return;
+    }
 
-    }
+  throw Exception ("Unknown target format: " + filename.string());
-  else if (strlen(cfilename) > 4 &&
-	   strcmp (&cfilename[strlen(cfilename)-4], "stle") == 0)
-    {
-      SaveSTLE (cfilename);
-    }
 }
 
 
@@ -1100,22 +1099,22 @@ void STLGeometry :: ExportEdges()
 
 }
 
-void STLGeometry :: LoadEdgeData(const char* file)
+void STLGeometry :: LoadEdgeData(const filesystem::path & filename)
 {
   StoreEdgeData();
 
-  PrintFnStart("Load edges from file '", file, "'");
+  PrintFnStart("Load edges from file '", filename, "'");
-  ifstream fin(file);
+  ifstream fin(filename);
 
   edgedata->Read(fin);
 
   //  calcedgedataanglesnew = 1;
 }
 
-void STLGeometry :: SaveEdgeData(const char* file)
+void STLGeometry :: SaveEdgeData(const filesystem::path & filename)
 {
-  PrintFnStart("save edges to file '", file, "'");
+  PrintFnStart("save edges to file '", filename, "'");
-  ofstream fout(file);
+  ofstream fout(filename);
 
   edgedata->Write(fout);
 }
@@ -3627,7 +3626,7 @@ void STLGeometry :: SmoothGeometry ()
     }
 }
 
-void STLGeometry :: WriteChartToFile( ChartId chartnumber, string filename )
+void STLGeometry :: WriteChartToFile( ChartId chartnumber, filesystem::path filename )
 {
   PrintMessage(1,"write chart ", int(chartnumber), " to ", filename);
   Array<int> trignums;
@@ -3701,38 +3700,38 @@ void STLGeometry :: WriteChartToFile( ChartId chartnumber, string filename )
   class STLGeometryRegister : public GeometryRegister
   {
   public:
-    virtual NetgenGeometry * Load (string filename) const;
+    virtual NetgenGeometry * Load (const filesystem::path & filename) const;
   };
 
-  NetgenGeometry *  STLGeometryRegister :: Load (string filename) const
+  NetgenGeometry *  STLGeometryRegister :: Load (const filesystem::path & filename) const
   {
-    const char * cfilename = filename.c_str();
+    string ext = ToLower(filename.extension());
 
-    if (strcmp (&cfilename[strlen(cfilename)-3], "stl") == 0)
+    if (ext == ".stl")
       {
-	PrintMessage (1, "Load STL geometry file ", cfilename);
+	PrintMessage (1, "Load STL geometry file ", filename);
 
-	ifstream infile(cfilename);
+	ifstream infile(filename);
 
 	STLGeometry * hgeom = STLGeometry :: Load (infile);
 	hgeom -> edgesfound = 0;
 	return hgeom;
       }
-    else if (strcmp (&cfilename[strlen(cfilename)-4], "stlb") == 0)
+    else if (ext == ".stlb")
       {
-	PrintMessage (1, "Load STL binary geometry file ", cfilename);
+	PrintMessage (1, "Load STL binary geometry file ", filename);
 
-	ifstream infile(cfilename);
+	ifstream infile(filename);
 
 	STLGeometry * hgeom = STLGeometry :: LoadBinary (infile);
 	hgeom -> edgesfound = 0;
 	return hgeom;
       }
-    else if (strcmp (&cfilename[strlen(cfilename)-3], "nao") == 0)
+    else if (ext == ".nao")
       {
-	PrintMessage (1, "Load naomi (F. Kickinger) geometry file ", cfilename);
+	PrintMessage (1, "Load naomi (F. Kickinger) geometry file ", filename);
 
-	ifstream infile(cfilename);
+	ifstream infile(filename);
 
 	STLGeometry * hgeom = STLGeometry :: LoadNaomi (infile);
 	hgeom -> edgesfound = 0;

libsrc/stlgeom/stlgeom.hpp

@@ -190,7 +190,7 @@ namespace netgen
 
     void Clear();
 
-    virtual void Save (string filename) const override;
+    virtual void Save (const filesystem::path & filename) const override;
 
     bool CalcPointGeomInfo(int surfind, PointGeomInfo& gi, const Point<3> & p3) const override;
     PointGeomInfo ProjectPoint(INDEX surfind, Point<3> & p) const override;
@@ -236,8 +236,8 @@ namespace netgen
 	DLL_HEADER void ImportEdges();
 	DLL_HEADER void AddEdges(const NgArray<Point<3> >& eps);
 	DLL_HEADER void ExportEdges();
-	DLL_HEADER void LoadEdgeData(const char* file);
+	DLL_HEADER void LoadEdgeData(const filesystem::path & file);
-	DLL_HEADER void SaveEdgeData(const char* file);
+	DLL_HEADER void SaveEdgeData(const filesystem::path & file);
     //  void SetEdgeAtSelected(int mode);
   
 
@@ -475,7 +475,7 @@ namespace netgen
     int GenerateMesh (shared_ptr<Mesh> & mesh, MeshingParameters & mparam) override;
     
     // Add additional Point to chart to close the surface and write the resulting stl to a file
-    DLL_HEADER void WriteChartToFile( ChartId chartnumber, string filename="chart.slb" );
+    DLL_HEADER void WriteChartToFile( ChartId chartnumber, filesystem::path filename="chart.slb" );
   };
  
 

libsrc/stlgeom/stlpkg.cpp

@@ -36,7 +36,7 @@ namespace netgen
   class STLGeometryVisRegister : public GeometryRegister
   {
   public:
-    virtual NetgenGeometry * Load (string filename) const { return NULL; }
+    virtual NetgenGeometry * Load (const filesystem::path & filename) const { return NULL; }
     virtual VisualScene * GetVisualScene (const NetgenGeometry * geom) const;
     virtual void SetParameters (Tcl_Interp * interp) 
     {

libsrc/stlgeom/stltopology.cpp

@@ -90,7 +90,7 @@ STLGeometry *  STLTopology :: LoadBinary (istream & ist)
 }
 
 
-void STLTopology :: SaveBinary (const char* filename, const char* aname) const
+void STLTopology :: SaveBinary (const filesystem::path & filename, const char* aname) const
 {
   ofstream ost(filename);
   PrintFnStart("Write STL binary file '",filename,"'");
@@ -149,7 +149,7 @@ void STLTopology :: SaveBinary (const char* filename, const char* aname) const
 }
 
 
-void STLTopology :: SaveSTLE (const char* filename) const
+void STLTopology :: SaveSTLE (const filesystem::path & filename) const
 {
   ofstream outf (filename);
   int i, j;
@@ -266,7 +266,7 @@ STLGeometry *  STLTopology :: LoadNaomi (istream & ist)
   return geom;
 }
 
-void STLTopology :: Save (const char* filename) const
+void STLTopology :: Save (const filesystem::path & filename) const
 { 
   PrintFnStart("Write stl-file '",filename, "'");
 

libsrc/stlgeom/stltopology.hpp

@@ -316,9 +316,9 @@ public:
   static STLGeometry * Load (istream & ist);
   static STLGeometry * LoadBinary (istream & ist);
 
-  void Save (const char* filename) const;
+  void Save (const filesystem::path & filename) const;
-  void SaveBinary (const char* filename, const char* aname) const;
+  void SaveBinary (const filesystem::path & filename, const char* aname) const;
-  void SaveSTLE (const char * filename) const; // stores trigs and edges
+  void SaveSTLE (const filesystem::path & filename) const; // stores trigs and edges
 
   virtual void DoArchive(Archive& ar)
   {

ng/ngpkg.cpp

@@ -205,9 +205,9 @@ namespace netgen
 		   Tcl_Interp * interp,
 		   int argc, tcl_const char *argv[])
   {
-    string filename (argv[1]);
+    auto filename = filesystem::u8path(argv[1]);
 
-    if (filename.find(".vol") == string::npos) 
+    if (filename.string().find(".vol") == string::npos)
       {
 	return Ng_ImportMesh(clientData,interp,argc,argv);
       }
@@ -217,42 +217,15 @@ namespace netgen
     mesh = make_shared<Mesh>();
     try
       {
-        istream * infile;
+	mesh -> Load(filename);
-        // if (filename.substr (filename.length()-3, 3) == ".gz")
-        if (filename.find(".vol.gz") != string::npos)
-          infile = new igzstream (filename.c_str());
-        else
-          infile = new ifstream (filename.c_str());
-
-	// ifstream infile(filename.c_str());
-	mesh -> Load(*infile);
-        // vsmesh.SetMesh (mesh);
         SetGlobalMesh (mesh);
 
 #ifdef PARALLEL
 	MyMPI_SendCmd ("mesh");
 	mesh -> Distribute();
 #endif
-    auto geo = geometryregister.LoadFromMeshFile (*infile);
+        if(mesh->GetGeometry())
-    if(geo)
+          ng_geometry = mesh->GetGeometry();
-        ng_geometry = geo;
-    delete infile;
-
-	/*
-	string auxstring;
-	if(infile.good())
-	  {
-	    infile >> auxstring;
-	    if(auxstring == "csgsurfaces")
-	      {
-		CSGeometry * geometry = new CSGeometry ("");
-		geometry -> LoadSurfaces(infile);
-
-		delete ng_geometry;
-		ng_geometry = geometry;
-	      }
-	  }
-	*/
       }
     catch (NgException e)
       {