BUG: FixedList '<' operator using a template parameter (fixes #458)

- cannot use comparison of list sizes. Okay for UList, but not here.

STYLE:
- don't need two iterators for the '<' comparison, can just access
  internal storage directly

applications/test/FixedList/Test-FixedList.C

@@ -33,7 +33,6 @@ See also
 \*---------------------------------------------------------------------------*/
 
 #include "argList.H"
-#include "IOstreams.H"
 #include "FixedList.H"
 #include "IFstream.H"
 #include "OFstream.H"
@@ -64,6 +63,15 @@ int main(int argc, char *argv[])
     Info<< "list2:" << list2
         << " hash:" << FixedList<label, 4>::Hash<>()(list2) << endl;
 
+    // Using FixedList for content too
+    {
+        List<FixedList<label, 4>> twolists{list, list2};
+        Info<<"List of FixedList: " << flatOutput(twolists) << endl;
+        sort(twolists);
+        // outer-sort only
+        Info<<"sorted FixedList : " << flatOutput(twolists) << endl;
+    }
+
     Info<< "list: " << list << nl
         << "list2: " << list2 << endl;
     list.swap(list2);

src/OpenFOAM/containers/Lists/FixedList/FixedList.C

@@ -70,31 +70,24 @@ bool Foam::FixedList<T, Size>::operator!=(const FixedList<T, Size>& a) const
 template<class T, unsigned Size>
 bool Foam::FixedList<T, Size>::operator<(const FixedList<T, Size>& a) const
 {
-    for
-    (
-        const_iterator vi = cbegin(), ai = a.cbegin();
-        vi < cend() && ai < a.cend();
-        vi++, ai++
-    )
+    const T* const __restrict__ ptr1 = this->begin();
+    const T* const __restrict__ ptr2 = a.begin();
+
+    for (unsigned i=0; i<Size; ++i)
     {
-        if (*vi < *ai)
+        if (ptr1[i] < ptr2[i])
         {
             return true;
         }
-        else if (*vi > *ai)
+        else if (ptr1[i] > ptr2[i])
         {
             return false;
         }
     }
 
-    if (Size < a.Size)
-    {
-        return true;
-    }
-    else
-    {
-        return false;
-    }
+    // Contents look to be identical.
+    // The sizes are identical by definition (template parameter)
+    return false;
 }
 
 

src/OpenFOAM/containers/Lists/UList/UList.C

@@ -196,14 +196,8 @@ bool Foam::UList<T>::operator<(const UList<T>& a) const
         }
     }
 
-    if (this->size_ < a.size_)
-    {
-        return true;
-    }
-    else
-    {
-        return false;
-    }
+    // Contents look to be identical, or lists have different sizes
+    return (this->size_ < a.size_);
 }