diff --git a/src/include/map_range.cc.h b/src/include/map_range.cc.h
index f7633d1..8e22968 100644
--- a/src/include/map_range.cc.h
+++ b/src/include/map_range.cc.h
@@ -451,10 +451,7 @@ namespace MultiArrayTools
     template <class MapF, class... Ranges>
     std::vector<char> MapRange<MapF,Ranges...>::data() const
     {
-	DataHeader h;
-	h.spaceType = static_cast<int>( SpaceType::ANY );
-	h.metaSize = sizeof...(Ranges);
-	h.multiple = 1;
+	DataHeader h = dataHeader();
 	std::vector<char> out;
 	//out.reserve(h.metaSize + sizeof(DataHeader));
 	char* hcp = reinterpret_cast<char*>(&h);
@@ -462,6 +459,16 @@ namespace MultiArrayTools
 	RPackNum<sizeof...(Ranges)-1>::fillRangeDataVec(out, mSpace);
 	return out;
     }
+
+    template <class MapF, class... Ranges>
+    DataHeader MapRange<MapF,Ranges...>::dataHeader() const
+    {
+	DataHeader h;
+	h.spaceType = static_cast<int>( SpaceType::ANY );
+	h.metaSize = sizeof...(Ranges);
+	h.multiple = 1;
+        return h;
+    }
     
     template <class MapF, class... Ranges>
     typename MapRange<MapF,Ranges...>::IndexType MapRange<MapF,Ranges...>::begin() const
diff --git a/src/include/map_range.h b/src/include/map_range.h
index 57562d4..1b05612 100644
--- a/src/include/map_range.h
+++ b/src/include/map_range.h
@@ -257,7 +257,8 @@ namespace MultiArrayTools
 	virtual size_t size() const final;
 
 	virtual SpaceType spaceType() const final;
-	
+        virtual DataHeader dataHeader() const final;
+        
 	virtual std::string stringMeta(size_t pos) const final;
 	virtual std::vector<char> data() const final;
 	
diff --git a/src/include/ranges/anonymous_range.h b/src/include/ranges/anonymous_range.h
index 43b84d1..2ff289c 100644
--- a/src/include/ranges/anonymous_range.h
+++ b/src/include/ranges/anonymous_range.h
@@ -78,7 +78,8 @@ namespace MultiArrayTools
 	virtual IndexType end() const final;
 
 	virtual SpaceType spaceType() const final;
-	
+        virtual DataHeader dataHeader() const final;
+        
 	virtual std::string stringMeta(size_t pos) const final;
 	virtual std::vector<char> data() const final;
 	
diff --git a/src/include/ranges/dynamic_range.cc.h b/src/include/ranges/dynamic_range.cc.h
index 7e749fd..67ed416 100644
--- a/src/include/ranges/dynamic_range.cc.h
+++ b/src/include/ranges/dynamic_range.cc.h
@@ -459,10 +459,7 @@ namespace MultiArrayTools
     template <class EC>
     std::vector<char> DynamicRange<EC>::data() const
     {
-	DataHeader h;
-	h.spaceType = static_cast<int>( SpaceType::DYN );
-	h.metaSize = mOrig.size();
-	h.multiple = 1;
+	DataHeader h = dataHeader();
 	std::vector<char> out;
 	char* hcp = reinterpret_cast<char*>(&h);
 	out.insert(out.end(), hcp, hcp + sizeof(DataHeader));
@@ -473,6 +470,16 @@ namespace MultiArrayTools
 	return out;
     }
 
+    template <class EC>
+    DataHeader DynamicRange<EC>::dataHeader() const
+    {
+	DataHeader h;
+	h.spaceType = static_cast<int>( SpaceType::DYN );
+	h.metaSize = mOrig.size();
+	h.multiple = 1;
+        return h;
+    }
+    
     template <class EC>
     typename DynamicRange<EC>::IndexType DynamicRange<EC>::begin() const
     {
diff --git a/src/include/ranges/dynamic_range.h b/src/include/ranges/dynamic_range.h
index 6e5b4a2..c7be122 100644
--- a/src/include/ranges/dynamic_range.h
+++ b/src/include/ranges/dynamic_range.h
@@ -303,7 +303,8 @@ namespace MultiArrayTools
 	virtual IndexType end() const final;
 
 	virtual SpaceType spaceType() const final;
-	
+        virtual DataHeader dataHeader() const final;
+        
 	virtual std::string stringMeta(size_t pos) const final;
 	virtual std::vector<char> data() const final;
 	
diff --git a/src/include/ranges/multi_range.h b/src/include/ranges/multi_range.h
index 9534aa3..7b0b7cc 100644
--- a/src/include/ranges/multi_range.h
+++ b/src/include/ranges/multi_range.h
@@ -189,7 +189,8 @@ namespace MultiArrayTools
 	virtual size_t size() const final;
 
 	virtual SpaceType spaceType() const final;
-	
+        virtual DataHeader dataHeader() const final;
+        
 	virtual std::string stringMeta(size_t pos) const final;
 	virtual std::vector<char> data() const final;
 	
@@ -568,10 +569,7 @@ namespace MultiArrayTools
     template <class... Ranges>
     std::vector<char> MultiRange<Ranges...>::data() const
     {
-	DataHeader h;
-	h.spaceType = static_cast<int>( SpaceType::ANY );
-	h.metaSize = sizeof...(Ranges);
-	h.multiple = 1;
+	DataHeader h = dataHeader();
 	std::vector<char> out;
 	//out.reserve(h.metaSize + sizeof(DataHeader));
 	char* hcp = reinterpret_cast<char*>(&h);
@@ -579,6 +577,16 @@ namespace MultiArrayTools
 	RPackNum<sizeof...(Ranges)-1>::fillRangeDataVec(out, mSpace);
 	return out;
     }
+
+    template <class... Ranges>
+    DataHeader MultiRange<Ranges...>::dataHeader() const
+    {
+	DataHeader h;
+	h.spaceType = static_cast<int>( SpaceType::ANY );
+	h.metaSize = sizeof...(Ranges);
+	h.multiple = 1;
+        return h;
+    }
     
     template <class... Ranges>
     typename MultiRange<Ranges...>::IndexType MultiRange<Ranges...>::begin() const
diff --git a/src/include/ranges/range_base.h b/src/include/ranges/range_base.h
index 5c9e0f3..454584f 100644
--- a/src/include/ranges/range_base.h
+++ b/src/include/ranges/range_base.h
@@ -82,7 +82,7 @@ namespace MultiArrayTools
 	virtual std::vector<char> data() const = 0; // usefull when writing to files, etc...
 
 	virtual SpaceType spaceType() const = 0;
-	
+        virtual DataHeader dataHeader() const = 0;
 	//virtual bool regular() const = 0; // integer distance (e.g. 2,3,4,...)
 	//virtual bool linear() const = 0; // 1dim valuable (e.g. 2.45, 3.12, 3.56,...)
 	//virtual bool multi() const = 0; // mdim
diff --git a/src/include/ranges/range_types/classic_range.h b/src/include/ranges/range_types/classic_range.h
index ba07956..a232bec 100644
--- a/src/include/ranges/range_types/classic_range.h
+++ b/src/include/ranges/range_types/classic_range.h
@@ -39,7 +39,8 @@ namespace MultiArrayTools
 	virtual size_t dim() const final;
 
 	virtual SpaceType spaceType() const final;
-	
+        virtual DataHeader dataHeader() const final;
+        
 	virtual std::string stringMeta(size_t pos) const final;
 	virtual std::vector<char> data() const final;
 	
diff --git a/src/include/ranges/range_types/null_range.h b/src/include/ranges/range_types/null_range.h
index a4e5882..16e7c2c 100644
--- a/src/include/ranges/range_types/null_range.h
+++ b/src/include/ranges/range_types/null_range.h
@@ -49,7 +49,8 @@ namespace MultiArrayTools
 	virtual std::vector<char> data() const final;
 
 	virtual SpaceType spaceType() const final;
-	
+        virtual DataHeader dataHeader() const final;
+        
 	size_t get(size_t pos) const;
 	size_t getMeta(size_t metapos) const;
 	
diff --git a/src/include/ranges/range_types/space_range.h b/src/include/ranges/range_types/space_range.h
index 5d4878d..3187403 100644
--- a/src/include/ranges/range_types/space_range.h
+++ b/src/include/ranges/range_types/space_range.h
@@ -41,7 +41,8 @@ namespace MultiArrayTools
 	virtual std::vector<char> data() const final;
 
 	virtual SpaceType spaceType() const final;
-	
+        virtual DataHeader dataHeader() const final;
+        
 	int get(size_t pos) const;
 	size_t getMeta(int metaPos) const;
 	
diff --git a/src/include/ranges/range_types/spin_range.h b/src/include/ranges/range_types/spin_range.h
index b1f3e8c..5fdfa5b 100644
--- a/src/include/ranges/range_types/spin_range.h
+++ b/src/include/ranges/range_types/spin_range.h
@@ -42,7 +42,8 @@ namespace MultiArrayTools
 	virtual std::vector<char> data() const final;
 
 	virtual SpaceType spaceType() const final;
-	
+        virtual DataHeader dataHeader() const final;
+        
 	size_t get(size_t pos) const;
 	size_t getMeta(size_t metaPos) const;
 	
diff --git a/src/include/ranges/single_range.h b/src/include/ranges/single_range.h
index ff7047a..128edf3 100644
--- a/src/include/ranges/single_range.h
+++ b/src/include/ranges/single_range.h
@@ -197,7 +197,8 @@ namespace MultiArrayTools
 	virtual size_t dim() const final;
 
 	virtual SpaceType spaceType() const final;
-	
+        virtual DataHeader dataHeader() const final;
+        
 	virtual std::string stringMeta(size_t pos) const final;
 	virtual std::vector<char> data() const final;
 	
@@ -504,11 +505,7 @@ namespace MultiArrayTools
     template <typename U, SpaceType TYPE>
     std::vector<char> SingleRange<U,TYPE>::data() const
     {
-	DataHeader h;
-	h.spaceType = static_cast<int>( TYPE );
-	h.metaSize = metaSize(mSpace);
-	h.metaType = NumTypeMap<U>::num;
-	h.multiple = 0;
+        DataHeader h = dataHeader();
 	std::vector<char> out;
 	out.reserve(h.metaSize + sizeof(DataHeader));
 	char* hcp = reinterpret_cast<char*>(&h);
@@ -519,6 +516,17 @@ namespace MultiArrayTools
 	return out;
     }
     
+    template <typename U, SpaceType TYPE>
+    DataHeader SingleRange<U,TYPE>::dataHeader() const
+    {
+	DataHeader h;
+	h.spaceType = static_cast<int>( TYPE );
+	h.metaSize = metaSize(mSpace);
+	h.metaType = NumTypeMap<U>::num;
+	h.multiple = 0;
+        return h;
+    }
+    
     template <typename U, SpaceType TYPE>
     typename SingleRange<U,TYPE>::IndexType SingleRange<U,TYPE>::begin() const
     {
diff --git a/src/include/ranges/type_map.h b/src/include/ranges/type_map.h
index 17f31f9..117bfac 100644
--- a/src/include/ranges/type_map.h
+++ b/src/include/ranges/type_map.h
@@ -4,6 +4,7 @@
 
 #include <string>
 #include <vector>
+#include <array>
 #include <iostream>
 
 namespace MultiArrayTools
@@ -79,6 +80,8 @@ namespace MultiArrayTools
 	    pos = termpos + 1;
 	}
     }
+
+#define XCOMMAX() ,
     
 #define include_type(t,n) template <> struct TypeMap<n> { typedef t type; };\
     template <> struct NumTypeMap<t> { static constexpr size_t num = n; };
@@ -89,11 +92,21 @@ namespace MultiArrayTools
     include_type(float,4)
     include_type(double,5)
     include_type(std::string,6)
-   
+    include_type(std::vector<size_t>,101)
+    include_type(std::vector<int>,102)
+    include_type(std::vector<double>,105)
+    include_type(std::vector<std::string>,106)
+    include_type(std::array<size_t XCOMMAX() 2>,201)
+    include_type(std::array<int XCOMMAX() 2>,202)
+    include_type(std::array<size_t XCOMMAX() 3>,301)
+    include_type(std::array<int XCOMMAX() 3>,302)
+    
 #undef include_type
 }
 #endif
 
+#undef XCOMMAX
+
 #ifdef register_type
 
 register_type(1)
diff --git a/src/lib/ranges/anonymous_range.cc b/src/lib/ranges/anonymous_range.cc
index a52e494..5014aea 100644
--- a/src/lib/ranges/anonymous_range.cc
+++ b/src/lib/ranges/anonymous_range.cc
@@ -110,10 +110,7 @@ namespace MultiArrayTools
 
     std::vector<char> AnonymousRange::data() const
     {
-	DataHeader h;
-	h.spaceType = static_cast<int>( SpaceType::ANON );
-	h.metaSize = mOrig.size();
-	h.multiple = 1;
+	DataHeader h = dataHeader();
 	std::vector<char> out;
 	char* hcp = reinterpret_cast<char*>(&h);
 	out.insert(out.end(), hcp, hcp + sizeof(DataHeader));
@@ -123,7 +120,16 @@ namespace MultiArrayTools
 	}
 	return out;
     }
-    
+
+    DataHeader AnonymousRange::dataHeader() const
+    {
+	DataHeader h;
+	h.spaceType = static_cast<int>( SpaceType::ANON );
+	h.metaSize = mOrig.size();
+	h.multiple = 1;
+        return h;
+    }
+        
     size_t AnonymousRange::anonymousDim() const
     {
 	return mOrig.size();
diff --git a/src/lib/ranges/range_types/classic_range.cc b/src/lib/ranges/range_types/classic_range.cc
index d942fa9..9cdba7d 100644
--- a/src/lib/ranges/range_types/classic_range.cc
+++ b/src/lib/ranges/range_types/classic_range.cc
@@ -60,10 +60,7 @@ namespace MultiArrayTools
 
     std::vector<char> SingleRange<size_t,SpaceType::NONE>::data() const
     {
-	DataHeader h;
-	h.spaceType = static_cast<int>( SpaceType::NONE );
-	h.metaSize = sizeof(size_t);
-	h.multiple = 0;
+	DataHeader h = dataHeader();
 	std::vector<char> out;
 	out.reserve(h.metaSize + sizeof(DataHeader));
 	char* hcp = reinterpret_cast<char*>(&h);
@@ -73,6 +70,15 @@ namespace MultiArrayTools
 	return out;
     }
 
+    DataHeader SingleRange<size_t,SpaceType::NONE>::dataHeader() const
+    {
+	DataHeader h;
+	h.spaceType = static_cast<int>( SpaceType::NONE );
+	h.metaSize = sizeof(size_t);
+	h.multiple = 0;
+        return h;
+    }
+
     
     typename SingleRange<size_t,SpaceType::NONE>::IndexType SingleRange<size_t,SpaceType::NONE>::begin() const
     {
diff --git a/src/lib/ranges/range_types/null_range.cc b/src/lib/ranges/range_types/null_range.cc
index 4c5e5c7..d42ebb5 100644
--- a/src/lib/ranges/range_types/null_range.cc
+++ b/src/lib/ranges/range_types/null_range.cc
@@ -83,16 +83,22 @@ namespace MultiArrayTools
 
     std::vector<char> SingleRange<size_t,SpaceType::NUL>::data() const
     {
-	DataHeader h;
-	h.spaceType = static_cast<int>( SpaceType::NUL );
-	h.metaSize = 0;
-	h.multiple = 0;
+	DataHeader h = dataHeader(); 
 	std::vector<char> out;
 	out.reserve(h.metaSize + sizeof(DataHeader));
 	char* hcp = reinterpret_cast<char*>(&h);
 	out.insert(out.end(), hcp, hcp + sizeof(DataHeader));
 	return out;
     }
+
+    DataHeader SingleRange<size_t,SpaceType::NUL>::dataHeader() const
+    {
+	DataHeader h;
+	h.spaceType = static_cast<int>( SpaceType::NUL );
+	h.metaSize = 0;
+	h.multiple = 0;
+        return h;
+    }
    
     typename SingleRange<size_t,SpaceType::NUL>::IndexType SingleRange<size_t,SpaceType::NUL>::begin() const
     {
diff --git a/src/lib/ranges/range_types/space_range.cc b/src/lib/ranges/range_types/space_range.cc
index 3d537aa..e4ca7f3 100644
--- a/src/lib/ranges/range_types/space_range.cc
+++ b/src/lib/ranges/range_types/space_range.cc
@@ -66,10 +66,7 @@ namespace MultiArrayTools
 
     std::vector<char> SingleRange<int,SpaceType::PSPACE>::data() const
     {
-	DataHeader h;
-	h.spaceType = static_cast<int>( SpaceType::PSPACE );
-	h.metaSize = sizeof(size_t);
-	h.multiple = 0;
+	DataHeader h = dataHeader();
 	std::vector<char> out;
 	out.reserve(h.metaSize + sizeof(DataHeader));
 	char* hcp = reinterpret_cast<char*>(&h);
@@ -78,6 +75,15 @@ namespace MultiArrayTools
 	out.insert(out.end(), scp, scp + h.metaSize);
 	return out;
     }
+
+    DataHeader SingleRange<int,SpaceType::PSPACE>::dataHeader() const
+    {
+	DataHeader h;
+	h.spaceType = static_cast<int>( SpaceType::PSPACE );
+	h.metaSize = sizeof(size_t);
+	h.multiple = 0;
+        return h;
+    }
     
     typename SingleRange<int,SpaceType::PSPACE>::IndexType SingleRange<int,SpaceType::PSPACE>::begin() const
     {
diff --git a/src/lib/ranges/range_types/spin_range.cc b/src/lib/ranges/range_types/spin_range.cc
index c5c7b0e..b391481 100644
--- a/src/lib/ranges/range_types/spin_range.cc
+++ b/src/lib/ranges/range_types/spin_range.cc
@@ -63,17 +63,23 @@ namespace MultiArrayTools
 
     std::vector<char> SingleRange<size_t,SpaceType::SPIN>::data() const
     {
-	DataHeader h;
-	h.spaceType = static_cast<int>( SpaceType::SPIN );
-	h.metaSize = 0;
-	h.multiple = 0;
+	DataHeader h = dataHeader();
 	std::vector<char> out;
 	out.reserve(h.metaSize + sizeof(DataHeader));
 	char* hcp = reinterpret_cast<char*>(&h);
 	out.insert(out.end(), hcp, hcp + sizeof(DataHeader));
 	return out;
     }
-
+    
+    DataHeader SingleRange<size_t,SpaceType::SPIN>::dataHeader() const
+    {
+	DataHeader h;
+	h.spaceType = static_cast<int>( SpaceType::SPIN );
+	h.metaSize = 0;
+	h.multiple = 0;
+        return h;
+    }    
+    
     typename SingleRange<size_t,SpaceType::SPIN>::IndexType SingleRange<size_t,SpaceType::SPIN>::begin() const
     {
 	SingleIndex<size_t,SpaceType::SPIN> i( std::dynamic_pointer_cast<SingleRange<size_t,SpaceType::SPIN> >