From db9460f0bcba66a8e1e5630c3b9f170d5da69a76 Mon Sep 17 00:00:00 2001
From: Mark Olesen <Mark.Olesen@esi-group.com>
Date: Thu, 15 Jul 2021 13:08:54 +0200
Subject: [PATCH] ENH: copy construct FixedList from fixed subset of input

- remove construct from two iterators (#2083)
---
 applications/test/FixedList/Test-FixedList.C  | 12 +++++--
 .../containers/Lists/FixedList/FixedList.H    | 23 +++++++------
 .../containers/Lists/FixedList/FixedListI.H   | 34 ++++++++-----------
 3 files changed, 38 insertions(+), 31 deletions(-)

diff --git a/applications/test/FixedList/Test-FixedList.C b/applications/test/FixedList/Test-FixedList.C
index f75d77e3c8..c8648ae05f 100644
--- a/applications/test/FixedList/Test-FixedList.C
+++ b/applications/test/FixedList/Test-FixedList.C
@@ -280,16 +280,24 @@ int main(int argc, char *argv[])
 
 
     List<label> list3{0, 1, 2, 3};
-    FixedList<label, 4> list4(list3.begin(), list3.end());
+    FixedList<label, 4> list4(list3);
     Info<< "list3: " << list3 << nl
         << "list4: " << list4 << nl;
 
-    list4 = {1, 2, 3, 5};
+    list4 = {1, 20, 3, 40};
     Info<< "list4: " << list4 << nl;
 
     FixedList<label, 5> list5{0, 1, 2, 3, 4};
     Info<< "list5: " << list5 << nl;
 
+    {
+        const FixedList<label, 2> indices({3, 1});
+        FixedList<label, 2> list4b(list4, indices);
+
+        Info<< "subset " << list4 << " with " << indices << " -> "
+            << list4b << nl;
+    }
+
     List<FixedList<label, 2>> list6{{0, 1}, {2, 3}};
     Info<< "list6: " << list6 << nl;
 
diff --git a/src/OpenFOAM/containers/Lists/FixedList/FixedList.H b/src/OpenFOAM/containers/Lists/FixedList/FixedList.H
index 59588b2c62..a79a318d06 100644
--- a/src/OpenFOAM/containers/Lists/FixedList/FixedList.H
+++ b/src/OpenFOAM/containers/Lists/FixedList/FixedList.H
@@ -152,7 +152,7 @@ public:
         //- Construct and initialize all entries to zero
         inline explicit FixedList(const Foam::zero);
 
-        //- Copy construct from C-array
+        //- Copy construct from C-array (deprecated)
         inline explicit FixedList(const T list[N]);
 
         //- Copy construct
@@ -162,25 +162,28 @@ public:
         //- list elements
         inline FixedList(FixedList<T, N>&& list);
 
-        //- Construct given begin/end iterators
-        //  Uses std::distance when verifying the size.
-        template<class InputIterator>
-        inline FixedList(InputIterator begIter, InputIterator endIter);
-
-        //- Construct from an initializer list
+        //- Construct from an initializer list. Runtime size check
         inline FixedList(std::initializer_list<T> list);
 
-        //- Construct from UList
+        //- Construct from UList. Runtime size check
         inline explicit FixedList(const UList<T>& list);
 
-        //- Copy construct from a subset of the input
+        //- Copy construct from a subset of the input. No size check
+        template<unsigned AnyNum>
+        inline FixedList
+        (
+            const FixedList<T, AnyNum>& list,
+            const FixedList<label, N>& indices
+        );
+
+        //- Copy construct from a subset of the input. No size check
         inline FixedList
         (
             const UList<T>& list,
             const FixedList<label, N>& indices
         );
 
-        //- Construct from SLList
+        //- Construct from SLList. Runtime size check
         inline explicit FixedList(const SLList<T>& list);
 
         //- Construct from Istream
diff --git a/src/OpenFOAM/containers/Lists/FixedList/FixedListI.H b/src/OpenFOAM/containers/Lists/FixedList/FixedListI.H
index 4f7d544e46..78611d4764 100644
--- a/src/OpenFOAM/containers/Lists/FixedList/FixedListI.H
+++ b/src/OpenFOAM/containers/Lists/FixedList/FixedListI.H
@@ -28,7 +28,6 @@ License
 
 #include "UList.H"
 #include "SLList.H"
-#include <type_traits>
 #include <utility>
 
 // * * * * * * * * * * * * * Static Member Functions * * * * * * * * * * * * //
@@ -86,24 +85,6 @@ inline Foam::FixedList<T, N>::FixedList(FixedList<T, N>&& list)
 }
 
 
-template<class T, unsigned N>
-template<class InputIterator>
-inline Foam::FixedList<T, N>::FixedList
-(
-    InputIterator begIter,
-    InputIterator endIter
-)
-{
-    checkSize(std::distance(begIter, endIter));
-
-    for (unsigned i=0; i<N; ++i)
-    {
-        v_[i] = *begIter;
-        ++begIter;
-    }
-}
-
-
 template<class T, unsigned N>
 inline Foam::FixedList<T, N>::FixedList(std::initializer_list<T> list)
 {
@@ -130,6 +111,21 @@ inline Foam::FixedList<T, N>::FixedList(const UList<T>& list)
 }
 
 
+template<class T, unsigned N>
+template<unsigned AnyNum>
+inline Foam::FixedList<T, N>::FixedList
+(
+    const FixedList<T, AnyNum>& 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
 (