From ef92d314932e060d3779a9319a57cbe36f9f5b7a Mon Sep 17 00:00:00 2001
From: Mark Olesen <Mark.Olesen@esi-group.com>
Date: Thu, 26 Oct 2023 09:44:15 +0200
Subject: [PATCH] ENH: construct labelRange from begin/end value pair

---
 .../primitives/ranges/IntRange/IntRange.H     |  8 ++---
 .../primitives/ranges/IntRange/IntRanges.C    | 36 ++++++++++---------
 .../primitives/ranges/labelRange/labelRange.C | 32 ++++++++++++-----
 .../primitives/ranges/labelRange/labelRange.H | 14 +++++---
 4 files changed, 56 insertions(+), 34 deletions(-)

diff --git a/src/OpenFOAM/primitives/ranges/IntRange/IntRange.H b/src/OpenFOAM/primitives/ranges/IntRange/IntRange.H
index 7b6de4b07c..bebceb4b5d 100644
--- a/src/OpenFOAM/primitives/ranges/IntRange/IntRange.H
+++ b/src/OpenFOAM/primitives/ranges/IntRange/IntRange.H
@@ -99,7 +99,7 @@ public:
             template<class Int>
             constexpr bool operator()(const Int val) const noexcept
             {
-                return val > 0;
+                return (val > 0);
             }
         };
 
@@ -109,7 +109,7 @@ public:
             template<class Int>
             constexpr bool operator()(const Int val) const noexcept
             {
-                return val < 0;
+                return (val < 0);
             }
         };
 
@@ -119,7 +119,7 @@ public:
             template<class Int>
             constexpr bool operator()(const Int val) const noexcept
             {
-                return val >= 0;
+                return (val >= 0);
             }
         };
 
@@ -129,7 +129,7 @@ public:
             template<class Int>
             constexpr bool operator()(const Int val) const noexcept
             {
-                return val <= 0;
+                return (val <= 0);
             }
         };
 
diff --git a/src/OpenFOAM/primitives/ranges/IntRange/IntRanges.C b/src/OpenFOAM/primitives/ranges/IntRange/IntRanges.C
index 0b69add7d6..100e7ed564 100644
--- a/src/OpenFOAM/primitives/ranges/IntRange/IntRanges.C
+++ b/src/OpenFOAM/primitives/ranges/IntRange/IntRanges.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2020 OpenCFD Ltd.
+    Copyright (C) 2020-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -36,20 +36,6 @@ License
 namespace Foam
 {
 
-template<class T>
-inline static List<label> makeIdentity(const IntRange<T>& range)
-{
-    if (range.size() < 1)
-    {
-        return List<label>();
-    }
-
-    List<label> result(range.size());
-    std::iota(result.begin(), result.end(), range.start());
-
-    return result;
-}
-
 template<class T>
 inline static Istream& input(Istream& is, IntRange<T>& range)
 {
@@ -79,14 +65,30 @@ inline static Ostream& output(Ostream& os, const IntRange<T>& range)
 
 Foam::List<Foam::label> Foam::identity(const IntRange<int32_t>& range)
 {
-    return makeIdentity(range);
+    List<label> result;
+
+    if (range.size() > 0)
+    {
+        result.resize(range.size());
+        std::iota(result.begin(), result.end(), range.start());
+    }
+
+    return result;
 }
 
 
 #if defined(WM_LABEL_SIZE) && (WM_LABEL_SIZE >= 64)
 Foam::List<Foam::label> Foam::identity(const IntRange<int64_t>& range)
 {
-    return makeIdentity(range);
+    List<label> result;
+
+    if (range.size() > 0)
+    {
+        result.resize(range.size());
+        std::iota(result.begin(), result.end(), range.start());
+    }
+
+    return result;
 }
 #endif
 
diff --git a/src/OpenFOAM/primitives/ranges/labelRange/labelRange.C b/src/OpenFOAM/primitives/ranges/labelRange/labelRange.C
index 383acb5a53..d81ddc3707 100644
--- a/src/OpenFOAM/primitives/ranges/labelRange/labelRange.C
+++ b/src/OpenFOAM/primitives/ranges/labelRange/labelRange.C
@@ -29,6 +29,7 @@ License
 #include "labelRange.H"
 #include "List.H"
 #include "MinMax.H"
+#include "Pair.H"
 #include <numeric>
 
 // * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
@@ -45,10 +46,24 @@ Foam::labelRange::labelRange(const MinMax<label>& range) noexcept
 :
     labelRange()
 {
-    if (range.min() < range.max())
+    if (range.min() <= range.max())
     {
+        // max is inclusive, so size with +1. Hope for no overflow
         start() = range.min();
-        size()  = (range.max() - range.min()); // Hope for no overflow?
+        size()  = 1 + (range.max() - range.min());
+    }
+}
+
+
+Foam::labelRange::labelRange(const Pair<label>& start_end) noexcept
+:
+    labelRange()
+{
+    if (start_end.first() <= start_end.second())
+    {
+        // second is exclusive, so size directly. Hope for no overflow
+        start() = start_end.first();
+        size()  = (start_end.second() - start_end.first());
     }
 }
 
@@ -65,14 +80,13 @@ Foam::labelRange::labelRange(Istream& is)
 
 Foam::List<Foam::label> Foam::labelRange::labels() const
 {
-    if (size() < 0)
-    {
-        // Skip this check?
-        return List<label>();
-    }
+    List<label> result;
 
-    List<label> result(this->size());
-    std::iota(result.begin(), result.end(), this->start());
+    if (this->size() > 0)
+    {
+        result.resize(this->size());
+        std::iota(result.begin(), result.end(), this->start());
+    }
 
     return result;
 }
diff --git a/src/OpenFOAM/primitives/ranges/labelRange/labelRange.H b/src/OpenFOAM/primitives/ranges/labelRange/labelRange.H
index 585458166f..a35cc70c68 100644
--- a/src/OpenFOAM/primitives/ranges/labelRange/labelRange.H
+++ b/src/OpenFOAM/primitives/ranges/labelRange/labelRange.H
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011 OpenFOAM Foundation
-    Copyright (C) 2017-2022 OpenCFD Ltd.
+    Copyright (C) 2017-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -48,6 +48,7 @@ namespace Foam
 
 // Forward Declarations
 template<class T> class MinMax;
+template<class T> class Pair;
 
 /*---------------------------------------------------------------------------*\
                          Class labelRange Declaration
@@ -98,11 +99,16 @@ public:
             const bool adjustStart
         ) noexcept;
 
-        //- Construct from a min/max range, enforces non-negative size.
-        //- Does not adjust the start.
-        //  Passing an invalid min/max range results in an empty labelRange
+        //- Construct from a min/max range (both inclusive),
+        //- enforces non-negative size.
+        //  Passing an invalid range results in an empty labelRange
         explicit labelRange(const MinMax<label>& range) noexcept;
 
+        //- Construct from start (inclusive) and end (exclusive) values,
+        //- enforces non-negative size.
+        //  Passing an invalid range results in an empty labelRange
+        explicit labelRange(const Pair<label>& start_end) noexcept;
+
         //- Construct from Istream.
         explicit labelRange(Istream& is);