ENH: construct fixed-length items as a fixed-length subset (#1708)

For example,

    const edge meshE(patch.meshPoints(), patch.edges()[edgei]);

src/OpenFOAM/containers/Lists/FixedList/FixedList.H

@@ -173,6 +173,13 @@ public:
         //- Construct from UList
         inline explicit FixedList(const UList<T>& list);
 
+        //- Copy construct from a subset of the input
+        inline FixedList
+        (
+            const UList<T>& list,
+            const FixedList<label, N>& indices
+        );
+
         //- Construct from SLList
         inline explicit FixedList(const SLList<T>& list);
 

src/OpenFOAM/containers/Lists/FixedList/FixedListI.H

@@ -136,6 +136,20 @@ inline Foam::FixedList<T, N>::FixedList(const UList<T>& list)
 }
 
 
+template<class T, unsigned N>
+inline Foam::FixedList<T, N>::FixedList
+(
+    const UList<T>& list,
+    const FixedList<label, N>& indices
+)
+{
+    for (unsigned i=0; i<N; ++i)
+    {
+        v_[i] = list[indices[i]];
+    }
+}
+
+
 template<class T, unsigned N>
 inline Foam::FixedList<T, N>::FixedList(const SLList<T>& list)
 {

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

@@ -292,11 +292,11 @@ Foam::List<T>::List(List<T>& a, bool reuse)
 
 
 template<class T>
-Foam::List<T>::List(const UList<T>& list, const labelUList& mapAddressing)
+Foam::List<T>::List(const UList<T>& list, const labelUList& indices)
 :
-    UList<T>(nullptr, mapAddressing.size())
+    UList<T>(nullptr, indices.size())
 {
-    const label len = mapAddressing.size();
+    const label len = indices.size();
 
     if (len)
     {
@@ -306,12 +306,35 @@ Foam::List<T>::List(const UList<T>& list, const labelUList& mapAddressing)
 
         for (label i=0; i < len; ++i)
         {
-            vp[i] = list[mapAddressing[i]];
+            vp[i] = list[indices[i]];
         }
     }
 }
 
 
+template<class T>
+template<unsigned N>
+Foam::List<T>::List
+(
+    const UList<T>& list,
+    const FixedList<label,N>& indices
+)
+:
+    UList<T>(nullptr, label(N))
+{
+    const label len = label(N);
+
+    doAlloc();
+
+    List_ACCESS(T, (*this), vp);
+
+    for (label i=0; i < len; ++i)
+    {
+        vp[i] = list[indices[i]];
+    }
+}
+
+
 template<class T>
 template<class InputIterator>
 Foam::List<T>::List(InputIterator begIter, InputIterator endIter)

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

@@ -153,8 +153,12 @@ public:
         //- Construct as copy or re-use as specified
         List(List<T>& a, bool reuse);
 
-        //- Construct as subset
-        List(const UList<T>& list, const labelUList& mapAddressing);
+        //- Copy construct subset of list
+        List(const UList<T>& list, const labelUList& indices);
+
+        //- Copy construct subset of list
+        template<unsigned N>
+        List(const UList<T>& list, const FixedList<label, N>& indices);
 
         //- Construct given begin/end iterators.
         //  Uses std::distance for the size.

src/OpenFOAM/meshes/meshShapes/edge/edge.H

@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2015 OpenFOAM Foundation
-    Copyright (C) 2017-2019 OpenCFD Ltd.
+    Copyright (C) 2017-2020 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -67,7 +67,7 @@ class edge
 {
 public:
 
-    // Static data members
+    // Static Data Members
 
         static const char* const typeName;
 
@@ -92,6 +92,13 @@ public:
         //- Construct from list, sorted with first less-than second
         inline edge(const FixedList<label, 2>& list, const bool doSort);
 
+        //- Copy construct from a subset of the input
+        inline edge
+        (
+            const UList<label>& list,
+            const FixedList<label, 2>& indices
+        );
+
         //- Construct from Istream
         inline edge(Istream& is);
 

src/OpenFOAM/meshes/meshShapes/edge/edgeI.H

@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011 OpenFOAM Foundation
-    Copyright (C) 2017-2019 OpenCFD Ltd.
+    Copyright (C) 2017-2020 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -74,6 +74,16 @@ inline Foam::edge::edge(const FixedList<label, 2>& list, const bool doSort)
 {}
 
 
+inline Foam::edge::edge
+(
+    const labelUList& list,
+    const FixedList<label, 2>& indices
+)
+:
+    labelPair(list[indices.first()], list[indices.last()])
+{}
+
+
 inline Foam::edge::edge(Istream& is)
 :
     labelPair(is)

src/OpenFOAM/meshes/meshShapes/tetCell/tetCell.H

@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2017 OpenFOAM Foundation
-    Copyright (C) 2019 OpenCFD Ltd.
+    Copyright (C) 2019-2020 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -69,7 +69,7 @@ public:
 
     // Constructors
 
-        //- Construct null, with invalid point labels (-1)
+        //- Default construct, with invalid point labels (-1)
         inline tetCell();
 
         //- Construct from four point labels
@@ -81,11 +81,18 @@ public:
             const label d
         );
 
-        //- Construct from FixedList of four point labels
-        inline tetCell(const FixedList<label, 4>& lst);
-
         //- Construct from an initializer list of four point labels
-        inline explicit tetCell(std::initializer_list<label> lst);
+        inline explicit tetCell(std::initializer_list<label> list);
+
+        //- Construct from FixedList of four point labels
+        inline tetCell(const FixedList<label, 4>& list);
+
+        //- Copy construct from a subset of the input list
+        inline tetCell
+        (
+            const labelUList& list,
+            const FixedList<label, 4>& indices
+        );
 
         //- Construct from Istream
         inline tetCell(Istream& is);

src/OpenFOAM/meshes/meshShapes/tetCell/tetCellI.H

@@ -6,6 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
+    Copyright (C) 2017-2020 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -52,15 +53,25 @@ inline Foam::tetCell::tetCell
 }
 
 
-inline Foam::tetCell::tetCell(const FixedList<label, 4>& lst)
+inline Foam::tetCell::tetCell(std::initializer_list<label> list)
 :
-    FixedList<label, 4>(lst)
+    FixedList<label, 4>(list)
 {}
 
 
-inline Foam::tetCell::tetCell(std::initializer_list<label> lst)
+inline Foam::tetCell::tetCell(const FixedList<label, 4>& list)
 :
-    FixedList<label, 4>(lst)
+    FixedList<label, 4>(list)
+{}
+
+
+inline Foam::tetCell::tetCell
+(
+    const labelUList& list,
+    const FixedList<label, 4>& indices
+)
+:
+    FixedList<label, 4>(list, indices)
 {}
 
 

src/OpenFOAM/meshes/meshShapes/triFace/triFace.H

@@ -56,7 +56,7 @@ SourceFiles
 namespace Foam
 {
 
-// Forward declarations
+// Forward Declarations
 class face;
 class triFace;
 
@@ -72,7 +72,6 @@ class triFace
 :
     public FixedList<label, 3>
 {
-
 public:
 
     // Constructors
@@ -88,11 +87,18 @@ public:
             const label c
         );
 
-        //- Copy construct from a list of three point labels.
-        inline explicit triFace(const labelUList& lst);
-
         //- Construct from an initializer list of three point labels
-        inline explicit triFace(std::initializer_list<label> lst);
+        inline explicit triFace(std::initializer_list<label> list);
+
+        //- Copy construct from a list of three point labels.
+        inline explicit triFace(const labelUList& list);
+
+        //- Copy construct from a subset of the input
+        inline triFace
+        (
+            const labelUList& list,
+            const FixedList<label, 3>& indices
+        );
 
         //- Construct from Istream
         inline triFace(Istream& is);

src/OpenFOAM/meshes/meshShapes/triFace/triFaceI.H

@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2013 OpenFOAM Foundation
-    Copyright (C) 2017-2018 OpenCFD Ltd.
+    Copyright (C) 2017-2020 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -81,15 +81,25 @@ inline Foam::triFace::triFace
 }
 
 
-inline Foam::triFace::triFace(const labelUList& lst)
+inline Foam::triFace::triFace(std::initializer_list<label> list)
 :
-    FixedList<label, 3>(lst)
+    FixedList<label, 3>(list)
 {}
 
 
-inline Foam::triFace::triFace(std::initializer_list<label> lst)
+inline Foam::triFace::triFace(const labelUList& list)
 :
-    FixedList<label, 3>(lst)
+    FixedList<label, 3>(list)
+{}
+
+
+inline Foam::triFace::triFace
+(
+    const labelUList& list,
+    const FixedList<label, 3>& indices
+)
+:
+    FixedList<label, 3>(list, indices)
 {}
 
 

src/OpenFOAM/meshes/primitiveShapes/tetrahedron/tetPoints.H

@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2012 OpenFOAM Foundation
-    Copyright (C) 2017 OpenCFD Ltd.
+    Copyright (C) 2017-2020 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -59,7 +59,7 @@ public:
 
     // Constructors
 
-        //- Construct null
+        //- Default construct
         inline tetPoints()
         {}
 
@@ -78,6 +78,17 @@ public:
             operator[](3) = d;
         }
 
+        //- Copy construct from subset of points
+        inline tetPoints
+        (
+            const UList<point>& points,
+            const FixedList<label, 4>& indices
+        )
+        :
+            FixedList<point, 4>(points, indices)
+        {}
+
+
     // Member Functions
 
         //- Return the tetrahedron

src/OpenFOAM/meshes/primitiveShapes/triangle/triPoints.H

@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2015 OpenFOAM Foundation
-    Copyright (C) 2017 OpenCFD Ltd.
+    Copyright (C) 2017-2020 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -58,7 +58,7 @@ public:
 
     // Constructors
 
-        //- Construct null
+        //- Default construct
         inline triPoints()
         {}
 
@@ -75,6 +75,16 @@ public:
             operator[](2) = c;
         }
 
+        //- Copy construct from subset of points
+        inline triPoints
+        (
+            const UList<point>& points,
+            const FixedList<label, 3>& indices
+        )
+        :
+            FixedList<point, 3>(points, indices)
+        {}
+
 
     // Member Functions