Add methods to get property values as strings

Surface_mesh/include/CGAL/Surface_mesh/Properties.h

@@ -69,10 +69,12 @@ public:
     /// Return the type_info of the property
     virtual const std::type_info& type() = 0;
 
+    /// Get element as a string
+    virtual const std::string to_str(size_t i) const = 0;
+  
     /// Return the name of the property
     const std::string& name() const { return name_; }
 
-
 protected:
 
     std::string name_;
@@ -147,7 +149,35 @@ public: // virtual interface of Base_property_array
 
     virtual const std::type_info& type() { return typeid(T); }
 
+    virtual const std::string to_str(size_t i) const
+    {
+      std::string out;
+      // Work-around to display char and uchar as integer numbers and not characters
+      get_string (out, data_[i]);
+      return out;
+    }
 
+    template <typename Type>
+    void get_string (std::string& out, const Type& t) const
+    {
+      std::ostringstream oss;
+      oss << t;
+      out = oss.str();
+    }
+
+    void get_string (std::string& out, const char& t) const
+    {
+      std::ostringstream oss;
+      oss << (int)t;
+      out = oss.str();
+    }
+    void get_string (std::string& out, const unsigned char& t) const
+    {
+      std::ostringstream oss;
+      oss << (int)t;
+      out = oss.str();
+    }
+  
 public:
 
     /// Get pointer to array (does not work for T==bool)
@@ -379,7 +409,15 @@ public:
             parrays_[i]->swap(i0, i1);
     }
 
-
+    std::string to_str (const Key& key) const
+    {
+      std::ostringstream oss;
+      for (std::size_t i = 0; i < parrays_.size(); ++ i)
+        oss << parrays_[i]->to_str((std::size_t)key) << " ";
+      oss << std::endl;
+      return oss.str();
+    }
+    
 private:
     std::vector<Base_property_array*>  parrays_;
     size_t  size_;