added edge/triFace to the hashing tests

applications/test/Hashing/hashingTests

@@ -36,5 +36,24 @@ labelListList
     (0 1 100 1000)
 )
 
+// edges are hashed commutatively
+edgeList
+(
+    (0 1)
+    (1 0)
+    (45 100)
+    (100 45)
+    (128 1000)
+    (1000 128)
+)
+
+// triFaces are also hashed commutatively (via multiply/add)
+triFaceList
+(
+    (10 20 30)
+    (30 20 10)
+    (20 10 30)
+)
+
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

applications/test/Hashing/testHashing.C

@@ -36,6 +36,8 @@ Description
 #include "stringList.H"
 #include "labelList.H"
 #include "labelPair.H"
+#include "edgeList.H"
+#include "triFaceList.H"
 
 #include "Hash.H"
 
@@ -117,6 +119,44 @@ int main(int argc, char *argv[])
             }
 
         }
+        else if (listType == "edgeList")
+        {
+            Info<<"contiguous = " << contiguous<edge>() << endl << endl;
+
+            edgeList lst(is);
+
+            forAll(lst, i)
+            {
+                unsigned hash1 = Hash<edge>()(lst[i]);
+
+                // as FixedList
+                unsigned hash2 = labelPair::Hash<>()(lst[i]);
+
+                Info<< hex << hash1 << " (as FixedList: " << hash2
+                    << "): " << dec << lst[i] << endl;
+            }
+        }
+        else if (listType == "triFaceList")
+        {
+            Info<<"contiguous = " << contiguous<triFace>() << endl << endl;
+
+            triFaceList lst(is);
+
+            forAll(lst, i)
+            {
+                // direct value
+                unsigned hash1 = Hash<triFace>()(lst[i]);
+                unsigned hash2 = FixedList<label, 3>::Hash<>()(lst[i]);
+
+                Info<< hex << hash1 << " (as FixedList: " << hash2
+                    << "): " << dec << lst[i] << endl;
+            }
+        }
+        else
+        {
+            Info<< "unknown type: " << listType << endl;
+        }
+
     }
 
     return 0;

src/triSurface/tools/labelPair/labelPairLookup.H

@@ -26,26 +26,31 @@ Typedef
     Foam::labelPairLookup
 
 Description
-    Hash for two labels to other label. Used for e.g. for face1, face2 to
+    A HashTable for two labels to another label.
-    shared edge.
+    Used for e.g. for face1, face2 to shared edge.
 
-    Note: do NOT use edge! Our two faces are non commutative, first face is
+Note
-    from surface1, second face is from surface2.
+    The hash table is based on a FixedList and not edge, since an edge
+    hashes commutatively!
 
 \*---------------------------------------------------------------------------*/
 
 #ifndef labelPairLookup_H
 #define labelPairLookup_H
 
+#include "FixedList.H"
 #include "HashTable.H"
-#include "edge.H"
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
 namespace Foam
 {
-    typedef HashTable<label, FixedList<label, 2>, FixedList<label, 2>::Hash<> >
+    typedef HashTable
-        labelPairLookup;
+    <
+       label,
+       FixedList<label, 2>,
+       FixedList<label, 2>::Hash<>
+    > labelPairLookup;
 }
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //