From 041be829fcc82e4e214e55c2ac1a4218a15c0582 Mon Sep 17 00:00:00 2001
From: Mark Olesen <Mark.Olesen@esi-group.com>
Date: Sat, 16 Feb 2019 16:08:43 +0100
Subject: [PATCH] ENH: improvements to label/scalar ranges

- construct from MinMax, optional start index for identity factory
  method to match Foam::identity()

- use GREAT instead of VGREAT in inverted scalarRange.
  Consistent with boundBox - to reduce the potential of overflow
  if calculating the span.

- add min()/max() methods to labelRange
---
 src/OpenFOAM/primitives/Tuple2/Tuple2.H       |  8 +-
 .../primitives/ranges/MinMax/MinMax.H         | 12 +--
 .../primitives/ranges/MinMax/MinMaxI.H        |  8 +-
 .../primitives/ranges/labelRange/labelRange.C | 16 +++-
 .../primitives/ranges/labelRange/labelRange.H | 34 ++++++--
 .../ranges/labelRange/labelRangeI.H           | 20 ++++-
 .../ranges/scalarRange/scalarRange.C          | 57 ++++++++++++-
 .../ranges/scalarRange/scalarRange.H          | 85 +++++++++++++------
 .../ranges/scalarRange/scalarRangeI.H         | 70 ++++++++-------
 9 files changed, 225 insertions(+), 85 deletions(-)

diff --git a/src/OpenFOAM/primitives/Tuple2/Tuple2.H b/src/OpenFOAM/primitives/Tuple2/Tuple2.H
index c47c96f992..599649d9a0 100644
--- a/src/OpenFOAM/primitives/Tuple2/Tuple2.H
+++ b/src/OpenFOAM/primitives/Tuple2/Tuple2.H
@@ -114,25 +114,25 @@ public:
     // Member Functions
 
         //- Return first
-        inline const T1& first() const
+        inline const T1& first() const noexcept
         {
             return f_;
         }
 
         //- Return first
-        inline T1& first()
+        inline T1& first() noexcept
         {
             return f_;
         }
 
         //- Return second
-        inline const T2& second() const
+        inline const T2& second() const noexcept
         {
             return s_;
         }
 
         //- Return second
-        inline T2& second()
+        inline T2& second() noexcept
         {
             return s_;
         }
diff --git a/src/OpenFOAM/primitives/ranges/MinMax/MinMax.H b/src/OpenFOAM/primitives/ranges/MinMax/MinMax.H
index 2400289f6b..1cd0243075 100644
--- a/src/OpenFOAM/primitives/ranges/MinMax/MinMax.H
+++ b/src/OpenFOAM/primitives/ranges/MinMax/MinMax.H
@@ -112,8 +112,8 @@ template<class T> class MinMax;
 class zero;
 
 // Common min/max types
-typedef MinMax<label> labelMinMax;
-typedef MinMax<scalar> scalarMinMax;
+typedef MinMax<label> labelMinMax;      //!< A label min/max range
+typedef MinMax<scalar> scalarMinMax;    //!< A scalar min/max range
 
 
 /*---------------------------------------------------------------------------*\
@@ -164,16 +164,16 @@ public:
     // Access
 
         //- The min value (first)
-        inline const T& min() const;
+        inline const T& min() const noexcept;
 
         //- The min value (first)
-        inline T& min();
+        inline T& min() noexcept;
 
         //- The max value (second)
-        inline const T& max() const;
+        inline const T& max() const noexcept;
 
         //- The max value (second)
-        inline T& max();
+        inline T& max() noexcept;
 
         //- The min/max average value
         inline T centre() const;
diff --git a/src/OpenFOAM/primitives/ranges/MinMax/MinMaxI.H b/src/OpenFOAM/primitives/ranges/MinMax/MinMaxI.H
index 5775178312..83033baf14 100644
--- a/src/OpenFOAM/primitives/ranges/MinMax/MinMaxI.H
+++ b/src/OpenFOAM/primitives/ranges/MinMax/MinMaxI.H
@@ -79,28 +79,28 @@ inline Foam::MinMax<T>::MinMax(const UList<T>& vals)
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
 template<class T>
-inline const T& Foam::MinMax<T>::min() const
+inline const T& Foam::MinMax<T>::min() const noexcept
 {
     return this->first();
 }
 
 
 template<class T>
-inline T& Foam::MinMax<T>::min()
+inline T& Foam::MinMax<T>::min() noexcept
 {
     return this->first();
 }
 
 
 template<class T>
-inline const T& Foam::MinMax<T>::max() const
+inline const T& Foam::MinMax<T>::max() const noexcept
 {
     return this->second();
 }
 
 
 template<class T>
-inline T& Foam::MinMax<T>::max()
+inline T& Foam::MinMax<T>::max() noexcept
 {
     return this->second();
 }
diff --git a/src/OpenFOAM/primitives/ranges/labelRange/labelRange.C b/src/OpenFOAM/primitives/ranges/labelRange/labelRange.C
index 1d8bc2df26..ff4f9ab652 100644
--- a/src/OpenFOAM/primitives/ranges/labelRange/labelRange.C
+++ b/src/OpenFOAM/primitives/ranges/labelRange/labelRange.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2017-2018 OpenCFD Ltd.
+    \\  /    A nd           | Copyright (C) 2017-2019 OpenCFD Ltd.
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
                             | Copyright (C) 2011 OpenFOAM Foundation
@@ -26,6 +26,7 @@ License
 \*---------------------------------------------------------------------------*/
 
 #include "labelRange.H"
+#include "MinMax.H"
 #include "List.H"
 #include "token.H"
 #include <numeric>
@@ -42,6 +43,19 @@ const Foam::labelRange Foam::labelRange::null;
 
 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
+Foam::labelRange::labelRange(const MinMax<label>& range) noexcept
+:
+    start_(0),
+    size_(0)
+{
+    if (range.min() < range.max())
+    {
+        start_ = range.min();
+        size_  = (range.max() - range.min()); // Hope for no overflow?
+    }
+}
+
+
 Foam::labelRange::labelRange(Istream& is)
 :
     start_(0),
diff --git a/src/OpenFOAM/primitives/ranges/labelRange/labelRange.H b/src/OpenFOAM/primitives/ranges/labelRange/labelRange.H
index 36728915b0..4c65dd4d92 100644
--- a/src/OpenFOAM/primitives/ranges/labelRange/labelRange.H
+++ b/src/OpenFOAM/primitives/ranges/labelRange/labelRange.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2017-2018 OpenCFD Ltd.
+    \\  /    A nd           | Copyright (C) 2017-2019 OpenCFD Ltd.
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
                             | Copyright (C) 2011 OpenFOAM Foundation
@@ -44,11 +44,12 @@ SourceFiles
 namespace Foam
 {
 
-// Forward declarations
+// Forward Declarations
 class labelRange;
 class Istream;
 class Ostream;
 template<class T> class List;
+template<class T> class MinMax;
 
 Istream& operator>>(Istream& is, labelRange& range);
 Ostream& operator<<(Ostream& os, const labelRange& range);
@@ -67,6 +68,7 @@ class labelRange
         //- The length of the interval
         label size_;
 
+
 public:
 
     // STL type definitions
@@ -83,6 +85,7 @@ public:
 
     // Static Data Members
 
+        //- Debugging
         static int debug;
 
         //- An empty range with start=0, size=0.
@@ -106,14 +109,25 @@ public:
             const bool adjustStart
         ) noexcept;
 
+        //- Construct from a min/max range, enforcing non-negative size.
+        //- Does not adjust the start.
+        //  Passing an invalid min/max range results in an empty labelRange
+        explicit labelRange(const MinMax<label>& range) noexcept;
+
         //- Construct from Istream.
-        labelRange(Istream& is);
+        explicit labelRange(Istream& is);
 
 
     // Static Member Functions
 
-        //- An identity range with range[i] == i.
-        inline static labelRange identity(const label len) noexcept;
+        //- An identity range corresponding to (map[i] == i), or with
+        //- an optional start index, so that (map[i] == i+start)
+        //  The order of parameters is as per the Foam::identity() function.
+        inline static labelRange identity
+        (
+            const label len,
+            const label start=0
+        ) noexcept;
 
 
     // Member Functions
@@ -157,10 +171,16 @@ public:
         //- The effective size of the range
         inline label size() const noexcept;
 
-        //- The (inclusive) lower value of the range - same as start
+        //- The (inclusive) lower value of the range - same as start(), first()
+        inline label min() const noexcept;
+
+        //- The (inclusive) upper value of the range - same as last()
+        inline label max() const noexcept;
+
+        //- The (inclusive) lower value of the range - same as start()
         inline label first() const noexcept;
 
-        //- The (inclusive) upper value of the range
+        //- The (inclusive) upper value of the range - same as max()
         inline label last() const noexcept;
 
         //- The value before the start of the range
diff --git a/src/OpenFOAM/primitives/ranges/labelRange/labelRangeI.H b/src/OpenFOAM/primitives/ranges/labelRange/labelRangeI.H
index 625f0f18ad..d5006d5c80 100644
--- a/src/OpenFOAM/primitives/ranges/labelRange/labelRangeI.H
+++ b/src/OpenFOAM/primitives/ranges/labelRange/labelRangeI.H
@@ -161,9 +161,13 @@ inline const Foam::labelRange::const_iterator Foam::labelRange::cend() const
 
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
-inline Foam::labelRange Foam::labelRange::identity(const label len) noexcept
+inline Foam::labelRange Foam::labelRange::identity
+(
+    const label len,
+    const label start
+) noexcept
 {
-    return labelRange(0, len);
+    return labelRange(start, len);
 }
 
 
@@ -230,6 +234,18 @@ inline Foam::label Foam::labelRange::start() const noexcept
 }
 
 
+inline Foam::label Foam::labelRange::min() const noexcept
+{
+    return start_;
+}
+
+
+inline Foam::label Foam::labelRange::max() const noexcept
+{
+    return start_ + size_ - 1;
+}
+
+
 inline Foam::label Foam::labelRange::first() const noexcept
 {
     return start_;
diff --git a/src/OpenFOAM/primitives/ranges/scalarRange/scalarRange.C b/src/OpenFOAM/primitives/ranges/scalarRange/scalarRange.C
index 8da74e8444..221101fcf0 100644
--- a/src/OpenFOAM/primitives/ranges/scalarRange/scalarRange.C
+++ b/src/OpenFOAM/primitives/ranges/scalarRange/scalarRange.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2018 OpenCFD Ltd.
+    \\  /    A nd           | Copyright (C) 2018-2019 OpenCFD Ltd.
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -25,8 +25,22 @@ License
 
 #include "scalarRange.H"
 #include "string.H"
+#include "Switch.H"
+#include "MinMax.H"
 #include "error.H"
 
+// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
+
+const Foam::scalarRange Foam::scalarRange::null;
+
+const Foam::scalarRange Foam::scalarRange::always
+(
+    scalarRange::ALWAYS,
+    -Foam::GREAT,
+    Foam::GREAT
+);
+
+
 // * * * * * * * * * * * * * Static Member Functions * * * * * * * * * * * * //
 
 bool Foam::scalarRange::parse(const std::string& str, scalarRange& range)
@@ -39,10 +53,23 @@ bool Foam::scalarRange::parse(const std::string& str, scalarRange& range)
     {
         // No colon
 
-        if (str == "none")
+        // Use Switch to accept none/true/false.
+        // Do not accept shorter ones though (f|n|t|y) or (on|off|yes|no)
+        // since these are not really appropriate here.
+
+        if (str.size() >= 4)
         {
-            // "none" is an empty (inverse) range
-            return true;
+            Switch sw(str, true);
+
+            if (sw.valid())
+            {
+                if (sw)
+                {
+                    range = scalarRange::always;
+                }
+
+                return true; // parsed ok
+            }
         }
 
         // "VALUE"
@@ -106,6 +133,24 @@ Foam::scalarRange Foam::scalarRange::parse(const std::string& str)
 }
 
 
+// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
+
+Foam::scalarRange::scalarRange(const MinMax<label>& range) noexcept
+:
+    min_(range.min()),
+    max_(range.max()),
+    type_(max_ < min_ ? scalarRange::NONE : scalarRange::GE_LE)
+{}
+
+
+Foam::scalarRange::scalarRange(const MinMax<scalar>& range) noexcept
+:
+    min_(range.min()),
+    max_(range.max()),
+    type_(max_ < min_ ? scalarRange::NONE : scalarRange::GE_LE)
+{}
+
+
 // * * * * * * * * * * * * * * * Friend Operators  * * * * * * * * * * * * * //
 
 Foam::Ostream& Foam::operator<<(Ostream& os, const scalarRange& range)
@@ -130,6 +175,10 @@ Foam::Ostream& Foam::operator<<(Ostream& os, const scalarRange& range)
             os << range.min_ << ':' << range.max_;
             break;
 
+        case scalarRange::ALWAYS:
+            os << "true";
+            break;
+
         default:
             os << "none";
             break;
diff --git a/src/OpenFOAM/primitives/ranges/scalarRange/scalarRange.H b/src/OpenFOAM/primitives/ranges/scalarRange/scalarRange.H
index e13aa381fb..973f446de2 100644
--- a/src/OpenFOAM/primitives/ranges/scalarRange/scalarRange.H
+++ b/src/OpenFOAM/primitives/ranges/scalarRange/scalarRange.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2018 OpenCFD Ltd.
+    \\  /    A nd           | Copyright (C) 2018-2019 OpenCFD Ltd.
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -50,9 +50,11 @@ SourceFiles
 namespace Foam
 {
 
-// Forward declarations
+// Forward Declarations
 class scalarRange;
 class Ostream;
+template<class T> class MinMax;
+
 Ostream& operator<<(Ostream& os, const scalarRange& range);
 
 
@@ -65,43 +67,72 @@ class scalarRange
     //- Enumeration defining type of range test to use
     enum testType
     {
-        NONE = 0,   //!< An empty, invalid (inverse) range. Never matches.
+        NONE = 0,   //!< Empty or invalid (inverse) range. Never matches.
         EQ,         //!< A single value test.
         GE,         //!< Greater-than-equal.
         GT,         //!< Greater-than.
         LE,         //!< Less-than-equal.
         LT,         //!< Less-than.
-        GE_LE       //!< An inclusive range.
+        GE_LE,      //!< An inclusive range.
+        ALWAYS      //!< Placeholder range that always matches
     };
 
 
     // Private Member Data
 
-        //- The type of range test
-        enum testType type_;
-
         //- The min value of the range
         scalar min_;
 
         //- The max value of the range
         scalar max_;
 
+        //- The type of range test
+        enum testType type_;
+
         //- Construct from components without sanity checking
-        inline scalarRange(const testType type, scalar minVal, scalar maxVal);
+        inline scalarRange
+        (
+            const testType type,
+            const scalar minVal,
+            const scalar maxVal
+        ) noexcept;
 
 
 public:
 
+    // STL type definitions
+
+        //- Type of values the range contains
+        typedef scalar value_type;
+
+
+    // Static Data Members
+
+        //- An empty/inverted range that never matches
+        static const scalarRange null;
+
+        //- A range that always matches
+        static const scalarRange always;
+
+
     // Constructors
 
         //- Construct an empty (inverse) range
-        inline scalarRange();
+        inline scalarRange() noexcept;
 
         //- Construct an exact value matcher
-        inline explicit scalarRange(const scalar value);
+        inline explicit scalarRange(const scalar value) noexcept;
 
         //- Construct a range from min-value to max-value
-        inline scalarRange(const scalar minVal, const scalar maxVal);
+        inline scalarRange(const scalar minVal, const scalar maxVal) noexcept;
+
+        //- Copy construct from a min/max range.
+        //  Automatically decides if this is a GE_LE or NONE range
+        explicit scalarRange(const MinMax<label>& range) noexcept;
+
+        //- Copy construct from a min/max range.
+        //  Automatically decides if this is a GE_LE or NONE range
+        explicit scalarRange(const MinMax<scalar>& range) noexcept;
 
 
     // Static Constructors
@@ -124,37 +155,37 @@ public:
 
 
         //- Construct a greater-than-equals bound
-        inline static scalarRange ge(const scalar minVal);
+        inline static scalarRange ge(const scalar minVal) noexcept;
 
         //- Construct a greater-than bound
-        inline static scalarRange gt(const scalar minVal);
+        inline static scalarRange gt(const scalar minVal) noexcept;
 
         //- Construct a less-than-equals bound
-        inline static scalarRange le(const scalar maxVal);
+        inline static scalarRange le(const scalar maxVal) noexcept;
 
         //- Construct a less-than bound
-        inline static scalarRange lt(const scalar maxVal);
+        inline static scalarRange lt(const scalar maxVal) noexcept;
 
 
     // Member Functions
 
         //- Reset to an empty (inverse) range.
-        inline void clear();
+        inline void clear() noexcept;
 
-        //- True if bounds are empty (eg, inverted)
-        inline bool empty() const;
+        //- True if range is empty (eg, inverted)
+        inline bool empty() const noexcept;
 
-        //- True if bounds are non-empty.
-        inline bool valid() const;
+        //- True if range is non-empty.
+        inline bool valid() const noexcept;
 
-        //- True if the bounds represents a single value.
-        inline bool single() const;
+        //- True if the range bounds represent a single value.
+        inline bool single() const noexcept;
 
         //- The min value of the range.
-        inline scalar min() const;
+        inline scalar min() const noexcept;
 
         //- The max value of the range.
-        inline scalar max() const;
+        inline scalar max() const noexcept;
 
         //- A representative (average) value for the range.
         //  For GE, LE bounds it is the min/max value, respectively.
@@ -169,13 +200,13 @@ public:
         //- Identical to match(), for use as a predicate.
         inline bool operator()(const scalar& value) const;
 
-        inline bool operator==(const scalarRange& rhs) const;
-        inline bool operator!=(const scalarRange& rhs) const;
+        inline bool operator==(const scalarRange& rhs) const noexcept;
+        inline bool operator!=(const scalarRange& rhs) const noexcept;
 
 
     // IOstream Operators
 
-        //- Print information about the bounds.
+        //- Print information about the range.
         friend Ostream& operator<<(Ostream& os, const scalarRange& range);
 };
 
diff --git a/src/OpenFOAM/primitives/ranges/scalarRange/scalarRangeI.H b/src/OpenFOAM/primitives/ranges/scalarRange/scalarRangeI.H
index a5c33fbef7..7de2ee93b7 100644
--- a/src/OpenFOAM/primitives/ranges/scalarRange/scalarRangeI.H
+++ b/src/OpenFOAM/primitives/ranges/scalarRange/scalarRangeI.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2018 OpenCFD Ltd.
+    \\  /    A nd           | Copyright (C) 2018-2019 OpenCFD Ltd.
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -30,29 +30,33 @@ inline Foam::scalarRange::scalarRange
     const scalarRange::testType type,
     const scalar minVal,
     const scalar maxVal
-)
+) noexcept
 :
-    type_(type),
     min_(minVal),
-    max_(maxVal)
+    max_(maxVal),
+    type_(type)
 {}
 
 
-inline Foam::scalarRange::scalarRange()
+inline Foam::scalarRange::scalarRange() noexcept
 :
-    scalarRange(NONE, Foam::VGREAT, -Foam::VGREAT)
+    scalarRange(scalarRange::NONE, Foam::GREAT, -Foam::GREAT)
 {}
 
 
-inline Foam::scalarRange::scalarRange(const scalar value)
+inline Foam::scalarRange::scalarRange(const scalar value) noexcept
 :
-    scalarRange(EQ, value, value)
+    scalarRange(scalarRange::EQ, value, value)
 {}
 
 
-inline Foam::scalarRange::scalarRange(const scalar minVal, const scalar maxVal)
+inline Foam::scalarRange::scalarRange
+(
+    const scalar minVal,
+    const scalar maxVal
+) noexcept
 :
-    scalarRange(GE_LE, minVal, maxVal)
+    scalarRange(scalarRange::GE_LE, minVal, maxVal)
 {
     if (minVal > maxVal)
     {
@@ -65,24 +69,24 @@ inline Foam::scalarRange::scalarRange(const scalar minVal, const scalar maxVal)
 }
 
 
-inline Foam::scalarRange Foam::scalarRange::ge(const scalar minVal)
+inline Foam::scalarRange Foam::scalarRange::ge(const scalar minVal) noexcept
 {
     return scalarRange(GE, minVal, Foam::VGREAT);
 }
 
 
-inline Foam::scalarRange Foam::scalarRange::gt(const scalar minVal)
+inline Foam::scalarRange Foam::scalarRange::gt(const scalar minVal) noexcept
 {
     return scalarRange(GT, minVal, Foam::VGREAT);
 }
 
 
-inline Foam::scalarRange Foam::scalarRange::le(const scalar maxVal)
+inline Foam::scalarRange Foam::scalarRange::le(const scalar maxVal) noexcept
 {
     return scalarRange(LE, -Foam::VGREAT, maxVal);
 }
 
-inline Foam::scalarRange Foam::scalarRange::lt(const scalar maxVal)
+inline Foam::scalarRange Foam::scalarRange::lt(const scalar maxVal) noexcept
 {
     return scalarRange(LT, -Foam::VGREAT, maxVal);
 }
@@ -90,39 +94,39 @@ inline Foam::scalarRange Foam::scalarRange::lt(const scalar maxVal)
 
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
-inline void Foam::scalarRange::clear()
+inline void Foam::scalarRange::clear() noexcept
 {
+    min_ = Foam::GREAT;
+    max_ = -Foam::GREAT;
     type_ = scalarRange::NONE;
-    min_ = Foam::VGREAT;
-    max_ = -Foam::VGREAT;
 }
 
 
-inline bool Foam::scalarRange::empty() const
+inline bool Foam::scalarRange::empty() const noexcept
 {
     return type_ == NONE;
 }
 
 
-inline bool Foam::scalarRange::valid() const
+inline bool Foam::scalarRange::valid() const noexcept
 {
     return type_;
 }
 
 
-inline bool Foam::scalarRange::single() const
+inline bool Foam::scalarRange::single() const noexcept
 {
-    return type_ == EQ;
+    return type_ == scalarRange::EQ;
 }
 
 
-inline Foam::scalar Foam::scalarRange::min() const
+inline Foam::scalar Foam::scalarRange::min() const noexcept
 {
     return min_;
 }
 
 
-inline Foam::scalar Foam::scalarRange::max() const
+inline Foam::scalar Foam::scalarRange::max() const noexcept
 {
     return max_;
 }
@@ -132,9 +136,7 @@ inline Foam::scalar Foam::scalarRange::value() const
 {
     switch (type_)
     {
-        case EQ:
-            return min_;    // For equals, min and max are identical
-
+        case EQ:    // For equals, min and max are identical
         case GE:
         case GT:
             return min_;
@@ -144,9 +146,10 @@ inline Foam::scalar Foam::scalarRange::value() const
             return max_;
 
         case GE_LE:
-            return 0.5*(min_ + max_);
+            // Multiply before adding to avoid possible overflow
+            return (0.5 * min_) + (0.5 * max_);
 
-        default:
+        default:  // NONE or ALWAYS. Zero is reasonable dummy value.
             return 0;
     }
 }
@@ -162,6 +165,7 @@ inline bool Foam::scalarRange::match(const scalar& value) const
         case LE:    return (value <= max_);
         case LT:    return (value < max_);
         case GE_LE: return (value >= min_ && value <= max_);
+        case ALWAYS: return true;
         default:    return false;
     }
 }
@@ -175,13 +179,19 @@ inline bool Foam::scalarRange::operator()(const scalar& value) const
 }
 
 
-inline bool Foam::scalarRange::operator==(const scalarRange& rhs) const
+inline bool Foam::scalarRange::operator==
+(
+    const scalarRange& rhs
+) const noexcept
 {
     return (type_ == rhs.type_ && min_ == rhs.min_ && max_ == rhs.max_);
 }
 
 
-inline bool Foam::scalarRange::operator!=(const scalarRange& rhs) const
+inline bool Foam::scalarRange::operator!=
+(
+    const scalarRange& rhs
+) const noexcept
 {
     return !(operator==(rhs));
 }