subset constructor

applications/test/List/ListTest.C

@@ -46,7 +46,7 @@ int main(int argc, char *argv[])
     List<vector> list(IStringStream("1 ((0 1 2))")());
     Info<< list << endl;
 
-    List<vector> list2(IStringStream("((0 1 2) (3 4 5) (3 4 5))")());
+    List<vector> list2(IStringStream("((0 1 2) (3 4 5) (6 7 8))")());
     Info<< list2 << endl;
 
     Info<< findIndex(list2, vector(3, 4, 5)) << endl;
@@ -59,6 +59,13 @@ int main(int argc, char *argv[])
     Info<< list2 << nl
         << list3 << endl;
 
+
+    // Subset
+    const labelList map(IStringStream("2 (0 2)")());
+    List<vector> subList3(list3, map);
+    Info<< "Elements " << map << " out of " << list3
+        << " : " << subList3 << endl;
+
     return 0;
 }
 

src/OpenFOAM/containers/Lists/List/List.C

@@ -171,6 +171,29 @@ Foam::List<T>::List(List<T>& a, bool reUse)
 }
 
 
+// Construct as subset
+template<class T>
+Foam::List<T>::List(const UList<T>& a, const unallocLabelList& map)
+:
+    UList<T>(NULL, map.size())
+{
+    if (this->size_)
+    {
+        this->v_ = new T[this->size_];
+
+        List_ACCESS(T, (*this), vp);
+        List_CONST_ACCESS(T, a, ap);
+        List_FOR_ALL(map, i)
+            List_ELEM((*this), vp, i) = List_ELEM(a, ap, (map[i]));
+        List_END_FOR_ALL
+    }
+    else
+    {
+        this->v_ = 0;
+    }
+}
+
+
 // Construct given start and end iterators.
 template<class T>
 template<class InputIterator>

src/OpenFOAM/containers/Lists/List/List.H

@@ -68,6 +68,7 @@ template<class T> class SortableList;
 template<class T> class IndirectList;
 template<class T> class BiIndirectList;
 
+typedef UList<label> unallocLabelList;
 
 /*---------------------------------------------------------------------------*\
                            Class List Declaration
@@ -112,6 +113,9 @@ public:
         //- Construct as copy or re-use as specified.
         List(List<T>&, bool reUse);
 
+        //- Construct as subset.
+        List(const UList<T>&, const unallocLabelList& mapAddressing);
+
         //- Construct given start and end iterators.
         template<class InputIterator>
         List(InputIterator first, InputIterator last);