From ef14a415a97a58c8c7dfe3d13da56cad6ae6ecdb Mon Sep 17 00:00:00 2001
From: Andrew Heather <>
Date: Wed, 9 Mar 2022 11:32:00 +0000
Subject: [PATCH] ENH: ListOps - added uniqueSort function

---
 .../containers/Lists/ListOps/ListOps.H        |  4 +++
 .../Lists/ListOps/ListOpsTemplates.C          | 27 +++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/src/OpenFOAM/containers/Lists/ListOps/ListOps.H b/src/OpenFOAM/containers/Lists/ListOps/ListOps.H
index 1ac082a857..78efbc82ec 100644
--- a/src/OpenFOAM/containers/Lists/ListOps/ListOps.H
+++ b/src/OpenFOAM/containers/Lists/ListOps/ListOps.H
@@ -217,6 +217,10 @@ void uniqueOrder
 );
 
 
+//- Return sorted list with removal of duplicates
+template<class T>
+List<T> uniqueSort(const UList<T>& input);
+
 //- Inplace sorting and removal of duplicates.
 //  Do not use FixedList for the input list, since it doesn't resize.
 template<class ListType>
diff --git a/src/OpenFOAM/containers/Lists/ListOps/ListOpsTemplates.C b/src/OpenFOAM/containers/Lists/ListOps/ListOpsTemplates.C
index 0b4885f957..bcdeb8ea18 100644
--- a/src/OpenFOAM/containers/Lists/ListOps/ListOpsTemplates.C
+++ b/src/OpenFOAM/containers/Lists/ListOps/ListOpsTemplates.C
@@ -424,6 +424,33 @@ void Foam::uniqueOrder
 }
 
 
+template<class T>
+Foam::List<T> Foam::uniqueSort(const UList<T>& input)
+{
+    List<T> output(input);
+
+    const label len = output.size();
+
+    if (len > 1)
+    {
+        Foam::stableSort(output);
+
+        label count = 0;
+        for (label i = 1; i < len; ++i)
+        {
+            if (output[count] != output[i])
+            {
+                output[++count] = output[i];
+            }
+        }
+
+        output.resize(count+1);
+    }
+
+    return output;
+}
+
+
 template<class ListType>
 void Foam::inplaceUniqueSort(ListType& input)
 {