ENH: improvements for labelRange

- constexpr, noexcept.
  Added an 'at()' method for returning an iterator within the range
  and changed operator()(label) to have behaviour as per found().
  This makes the labelRange usable as a unary predicate.

- added templated conversion class 'toLabelRange'

- add range() method to polyPatch and surfZone classes, and corresponding
  templated conversion functors.
  For example,

      auto patchDims = ListOps::create<labelRange>
      (
          mesh.boundaryMesh(),
          toLabelRange<polyPatch>()
      );

  to create a List<labelRange> representing the patch extents.

src/OpenFOAM/meshes/polyMesh/polyPatches/polyPatch/polyPatch.H

@@ -315,6 +315,12 @@ public:
             return start_;
         }
 
+        //- Return start/size range of this patch
+        labelRange range() const
+        {
+            return labelRange(start_, this->size());
+        }
+
         //- Return boundaryMesh reference
         const polyBoundaryMesh& boundaryMesh() const;
 
@@ -423,6 +429,19 @@ public:
 };
 
 
+// Global Functions
+
+//- Get the labelRange for a polyPatch
+template<>
+struct toLabelRange<polyPatch>
+{
+    labelRange operator()(const polyPatch& pp) const
+    {
+        return pp.range();
+    }
+};
+
+
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
 } // End namespace Foam

src/OpenFOAM/primitives/ranges/labelRange/labelRange.C

@@ -26,7 +26,6 @@ License
 #include "labelRange.H"
 #include "token.H"
 
-
 // * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
 
 namespace Foam
@@ -50,23 +49,19 @@ Foam::labelRange::labelRange(Istream& is)
 
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
-void Foam::labelRange::adjust()
+void Foam::labelRange::adjust() noexcept
 {
     if (start_ < 0)
     {
-        if (size_ <= 0)
+        if (size_ > 0)  // Second check needed to avoid (negative) overflow
-        {
-            size_ = 0;
-        }
-        else
         {
             size_ += start_;
         }
         start_ = 0;
     }
-    else if (size_ < 0)
+    if (size_ < 0)
     {
-        size_ = 0;
+        size_ = 0;  // No negative sizes
     }
 }
 
@@ -96,7 +91,7 @@ bool Foam::labelRange::overlaps(const labelRange& range, bool touches) const
 
 Foam::labelRange Foam::labelRange::join(const labelRange& range) const
 {
-    // trivial cases first
+    // Trivial cases first
     if (!size_)
     {
         return *this;
@@ -128,11 +123,9 @@ Foam::labelRange Foam::labelRange::subset(const labelRange& range) const
     {
         return labelRange(lower, total);
     }
-    else
+
-    {
     return labelRange();
 }
-}
 
 
 Foam::labelRange Foam::labelRange::subset
@@ -151,11 +144,9 @@ Foam::labelRange Foam::labelRange::subset
     {
         return labelRange(lower, total);
     }
-    else
+
-    {
     return labelRange();
 }
-}
 
 
 Foam::labelRange Foam::labelRange::subset0(const label size) const
@@ -170,11 +161,9 @@ Foam::labelRange Foam::labelRange::subset0(const label size) const
     {
         return labelRange(lower, total);
     }
-    else
+
-    {
     return labelRange();
 }
-}
 
 
 // * * * * * * * * * * * * * * * Friend Operators  * * * * * * * * * * * * * //
@@ -185,21 +174,19 @@ Foam::Istream& Foam::operator>>(Istream& is, labelRange& range)
     is  >> range.start_ >> range.size_;
     is.readEnd("labelRange");
 
-    is.check(FUNCTION_NAME);
-
-    // Disallow invalid sizes
     if (range.size_ < 0)
     {
-        range.size_ = 0;
+        range.size_ = 0;  // No negative sizes
     }
 
+    is.check(FUNCTION_NAME);
     return is;
 }
 
 
 Foam::Ostream& Foam::operator<<(Ostream& os, const labelRange& range)
 {
-    // Write ASCII only for now
+    // Only write as ASCII for now
     os  << token::BEGIN_LIST
         << range.start() << token::SPACE << range.size()
         << token::END_LIST;

src/OpenFOAM/primitives/ranges/labelRange/labelRange.H

@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2011 OpenFOAM Foundation
-     \\/     M anipulation  | Copyright (C) 2017 OpenCFD Ltd.
+     \\/     M anipulation  | Copyright (C) 2017-2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -42,12 +42,11 @@ SourceFiles
 namespace Foam
 {
 
-// Forward declaration of classes
+// Forward declarations
+class labelRange;
 class Istream;
 class Ostream;
 
-// Forward declaration of friend functions and operators
-class labelRange;
 Istream& operator>>(Istream& is, labelRange& range);
 Ostream& operator<<(Ostream& os, const labelRange& range);
 
@@ -57,13 +56,28 @@ Ostream& operator<<(Ostream& os, const labelRange& range);
 
 class labelRange
 {
-    // Private data
+    // Private Data
 
+        //- The start point for the interval
         label start_;
+
+        //- The length of the interval
         label size_;
 
 public:
 
+    // STL type definitions
+
+        //- Type of values the range contains
+        typedef label value_type;
+
+        //- The type that can represent the size of the range
+        typedef label size_type;
+
+        //- Forward iterator with const access
+        class const_iterator;
+
+
     // Static Data Members
 
         static int debug;
@@ -72,22 +86,13 @@ public:
         static const labelRange null;
 
 
-    // STL type definitions similar to what UList has
-
-        //- Type of values the range contains
-        typedef label value_type;
-
-        //- The type that can represent the size of the range
-        typedef label size_type;
-
-        // Forward declaration
-        class const_iterator;
-
-
     // Constructors
 
         //- An empty range with zero for start/size.
-        inline labelRange();
+        inline constexpr labelRange() noexcept;
+
+        //- Construct a range from start/size, enforcing non-negative size.
+        inline labelRange(const label start, const label size) noexcept;
 
         //- Construct a range from start/size, enforcing non-negative size.
         //  Optionally adjust the start to avoid any negative indices.
@@ -95,8 +100,8 @@ public:
         (
             const label start,
             const label size,
-            const bool adjustStart = false
+            const bool adjustStart
-        );
+        ) noexcept;
 
         //- Construct from Istream.
         labelRange(Istream& is);
@@ -105,68 +110,75 @@ public:
     // Static Member Functions
 
         //- An identity range with range[i] == i.
-        inline static labelRange identity(const label len);
+        inline static labelRange identity(const label len) noexcept;
 
 
     // Member Functions
 
-        //- Adjust start position
+        //- Change the start position
-        inline void setStart(const label i);
+        inline void setStart(const label i) noexcept;
 
-        //- Adjust size
+        //- Change the size
-        inline void setSize(const label n);
+        inline void resize(const label n) noexcept;
 
-        //- Alias for setSize()
+        //- Change the size - alias for resize()
-        inline void resize(const label n);
+        inline void setSize(const label n) noexcept;
 
         //- Decrease the size by 1, but never below 0.
-        inline void decrement();
+        inline void decrement() noexcept;
 
         //- Increase the size by 1.
-        inline void increment();
+        inline void increment() noexcept;
 
         //- Reset to zero start and zero size
-        inline void clear();
+        inline void clear() noexcept;
 
         //- Is the range empty?
-        inline bool empty() const;
+        inline bool empty() const noexcept;
 
-        //- Adjust the start to avoid any negative indices
+        //- Adjust the start to avoid negative indices.
-        void adjust();
+        //  The size is decreased accordingly, but will never become negative.
+        //  Eg, adjusting (-10, 15) becomes (0,5).
+        //  adjusting (-20, 15) becomes (0,0)
+        void adjust() noexcept;
 
         //- Is the range non-empty?
-        inline bool valid() const;
+        inline bool valid() const noexcept;
 
         //- The (inclusive) lower value of the range
-        inline label start() const;
+        inline label start() const noexcept;
 
         //- The effective size of the range
-        inline label size() const;
+        inline label size() const noexcept;
 
         //- The (inclusive) lower value of the range - same as start
-        inline label first() const;
+        inline label first() const noexcept;
 
         //- The (inclusive) upper value of the range
-        inline label last() const;
+        inline label last() const noexcept;
 
         //- The value before the start of the range
-        inline label before() const;
+        inline label before() const noexcept;
 
         //- The value after the last element in the range
-        inline label after() const;
+        inline label after() const noexcept;
+
+        //- Reset start and size, enforcing non-negative size.
+        //  \return true if the updated range is valid (non-empty).
+        inline bool reset(const label start, const label size) noexcept;
 
         //- Reset start and size, enforcing non-negative size.
         //  Optionally adjust the start to avoid any negative indices.
-        //  Return true if the updated range valid (non-empty).
+        //  \return true if the updated range is valid (non-empty).
         inline bool reset
         (
             const label start,
             const label size,
-            const bool adjustStart = false
+            const bool adjustStart
-        );
+        ) noexcept;
 
-        //- Return true if the value is located the range
+        //- Return true if the (global) value is located within the range
-        inline bool found(const label value) const;
+        inline bool found(const label value) const noexcept;
 
         //- Return true if the ranges overlap.
         //  Optional test for ranges that also just touch each other
@@ -192,21 +204,29 @@ public:
         labelRange subset0(const label size) const;
 
 
+        //- Return const_iterator to element at in the range, with bounds
+        //- checking.
+        //  \return iterator at the requested position, or end() if it is
+        //      out of bounds
+        inline const_iterator at(const label localIndex) const;
+
+
     // Member Operators
 
-        //- Return element in the range, no bounds checking
+        //- Return element in the range, without bounds checking
-        inline label operator[](const label localIndex) const;
+        inline label operator[](const label localIndex) const noexcept;
 
-        //- Return const_iterator to element in the range
+        //- Return true if the (global) value is located within the range.
-        inline const_iterator operator()(const label localIndex) const;
+        //  Behaviour identical to found().
+        inline bool operator()(const label value) const noexcept;
 
         //- Increase the size by 1.
-        inline label operator++();
+        inline label operator++() noexcept;
-        inline label operator++(int);
+        inline label operator++(int) noexcept;
 
         //- Decrease the size by 1, but never below 0.
-        inline label operator--();
+        inline label operator--() noexcept;
-        inline label operator--(int);
+        inline label operator--(int) noexcept;
 
 
     // STL iterator
@@ -223,7 +243,7 @@ public:
                 const label&
             >
         {
-            //- The current (global) value
+            //- The current (global) index value
             label value_;
 
         public:
@@ -231,7 +251,8 @@ public:
           // Constructors
 
             //- Construct from range at given local index.
-            //  A negative index is invalid and corresponds to the 'end'
+            //  If the local index is out of range (eg, negaative),
+            //  this creates the 'end' iterator
             inline const_iterator(const labelRange* range, const label i=0);
 
           // Member operators
@@ -270,22 +291,28 @@ public:
 };
 
 
+// Global Functions
+
+//- Conversion to labelRange operations
+template<class Type> struct toLabelRange {};
+
+
 // Global Operators
 
-inline bool operator==(const labelRange& a, const labelRange& b)
+inline bool operator==(const labelRange& a, const labelRange& b) noexcept
 {
     return (a.first() == b.first() && a.size() == b.size());
 }
 
-inline bool operator!=(const labelRange& a, const labelRange& b)
+inline bool operator!=(const labelRange& a, const labelRange& b) noexcept
 {
-    return !(a == b);
+    return (a.first() != b.first() || a.size() != b.size());
 }
 
 
 //- Comparison function for sorting, compares the start.
 //  If the start values are equal, also compares the size.
-inline bool operator<(const labelRange& a, const labelRange& b)
+inline bool operator<(const labelRange& a, const labelRange& b) noexcept
 {
     return
     (
@@ -298,18 +325,18 @@ inline bool operator<(const labelRange& a, const labelRange& b)
     );
 }
 
-inline bool operator<=(const labelRange& a, const labelRange& b)
+inline bool operator<=(const labelRange& a, const labelRange& b) noexcept
 {
     return !(b < a);
 }
 
 
-inline bool operator>(const labelRange& a, const labelRange& b)
+inline bool operator>(const labelRange& a, const labelRange& b) noexcept
 {
     return (b < a);
 }
 
-inline bool operator>=(const labelRange& a, const labelRange& b)
+inline bool operator>=(const labelRange& a, const labelRange& b) noexcept
 {
     return !(a < b);
 }

src/OpenFOAM/primitives/ranges/labelRange/labelRangeI.H

@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2011-2016 OpenFOAM Foundation
-     \\/     M anipulation  | Copyright (C) 2017 OpenCFD Ltd.
+     \\/     M anipulation  | Copyright (C) 2017-2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -23,35 +23,47 @@ License
 
 \*---------------------------------------------------------------------------*/
 
-
 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
-inline Foam::labelRange::labelRange()
+inline constexpr Foam::labelRange::labelRange() noexcept
 :
     start_(0),
     size_(0)
 {}
 
 
+inline Foam::labelRange::labelRange
+(
+    const label start,
+    const label size
+) noexcept
+:
+    start_(start),
+    size_(size)
+{
+    if (size_ < 0)
+    {
+        size_ = 0;  // No negative sizes
+    }
+}
+
 inline Foam::labelRange::labelRange
 (
     const label start,
     const label size,
     const bool adjustStart
-)
+) noexcept
 :
     start_(start),
     size_(size)
 {
     if (adjustStart)
     {
-        // Disallow invalid indices and sizes
+        adjust(); // Eliminate negative start, adjust size accordingly
-        adjust();
     }
     else if (size_ < 0)
     {
-        // Disallow invalid sizes
+        size_ = 0;  // No negative sizes
-        size_ = 0;
     }
 }
 
@@ -89,7 +101,7 @@ Foam::labelRange::const_iterator::operator++()
 inline Foam::labelRange::const_iterator
 Foam::labelRange::const_iterator::operator++(int)
 {
-    const_iterator old = *this;
+    const_iterator old(*this);
     ++value_;
     return old;
 }
@@ -125,6 +137,14 @@ inline Foam::labelRange::const_iterator Foam::labelRange::cbegin() const
 }
 
 
+inline Foam::labelRange::const_iterator
+Foam::labelRange::at(const label localIndex) const
+{
+    // The constructor handles out-of-range properly
+    return const_iterator(this, localIndex);
+}
+
+
 inline const Foam::labelRange::const_iterator Foam::labelRange::end() const
 {
     return const_iterator(this, -1);
@@ -139,93 +159,94 @@ inline const Foam::labelRange::const_iterator Foam::labelRange::cend() const
 
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
-inline Foam::labelRange Foam::labelRange::identity(const label len)
+inline Foam::labelRange Foam::labelRange::identity(const label len) noexcept
 {
     return labelRange(0, len);
 }
 
 
-inline void Foam::labelRange::setStart(const label i)
+inline void Foam::labelRange::setStart(const label i) noexcept
 {
     start_ = i;
 }
 
 
-inline void Foam::labelRange::setSize(const label n)
+inline void Foam::labelRange::resize(const label n) noexcept
 {
     size_ = n;
-    if (size_ < 0) size_ = 0;
+    if (size_ < 0) size_ = 0;  // No negative sizes
 }
 
 
-inline void Foam::labelRange::resize(const label n)
+inline void Foam::labelRange::setSize(const label n) noexcept
 {
-    setSize(n);
+    size_ = n;
+    if (size_ < 0) size_ = 0;  // No negative sizes
 }
 
 
-inline void Foam::labelRange::decrement()
+inline void Foam::labelRange::decrement() noexcept
 {
     --size_;
-    if (size_ < 0) size_ = 0;
+    if (size_ < 0) size_ = 0;  // No negative sizes
 }
 
 
-inline void Foam::labelRange::increment()
+inline void Foam::labelRange::increment() noexcept
 {
     ++size_;
 }
 
 
-inline void Foam::labelRange::clear()
+inline void Foam::labelRange::clear() noexcept
 {
     start_ = size_ = 0;
 }
 
 
-inline bool Foam::labelRange::empty() const
+inline bool Foam::labelRange::empty() const noexcept
 {
     return !size_;
 }
 
 
-inline bool Foam::labelRange::valid() const
+inline bool Foam::labelRange::valid() const noexcept
 {
     return size_;
 }
 
 
-inline Foam::label Foam::labelRange::size() const
+inline Foam::label Foam::labelRange::size() const noexcept
 {
     return size_;
 }
 
 
-inline Foam::label Foam::labelRange::start() const
+inline Foam::label Foam::labelRange::start() const noexcept
 {
     return start_;
 }
 
 
-inline Foam::label Foam::labelRange::first() const
+inline Foam::label Foam::labelRange::first() const noexcept
 {
     return start_;
 }
 
 
-inline Foam::label Foam::labelRange::last() const
+inline Foam::label Foam::labelRange::last() const noexcept
 {
     return start_ + size_ - 1;
 }
 
 
-inline Foam::label Foam::labelRange::before() const
+inline Foam::label Foam::labelRange::before() const noexcept
 {
     return start_ - 1;
 }
 
 
-inline Foam::label Foam::labelRange::after() const
+inline Foam::label Foam::labelRange::after() const noexcept
 {
     return start_ + size_;
 }
@@ -234,29 +255,45 @@ inline Foam::label Foam::labelRange::after() const
 inline bool Foam::labelRange::reset
 (
     const label start,
-    const label size,
+    const label size
-    const bool adjustStart
+) noexcept
-)
 {
     start_ = start;
     size_  = size;
 
-    if (adjustStart)
+    if (size_ < 0)
     {
-        // Disallow invalid indices and sizes
+        size_ = 0;  // No negative sizes
-        adjust();
-    }
-    else if (size_ < 0)
-    {
-        // Disallow invalid sizes
-        size_ = 0;
     }
 
     return size_;
 }
 
 
-inline bool Foam::labelRange::found(const label value) const
+inline bool Foam::labelRange::reset
+(
+    const label start,
+    const label size,
+    const bool adjustStart
+) noexcept
+{
+    start_ = start;
+    size_  = size;
+
+    if (adjustStart)
+    {
+        adjust(); // Eliminate negative start, adjust size accordingly
+    }
+    else if (size_ < 0)
+    {
+        size_ = 0;  // No negative sizes
+    }
+
+    return size_;
+}
+
+
+inline bool Foam::labelRange::found(const label value) const noexcept
 {
     return (value >= this->first() && value <= this->last());
 }
@@ -264,41 +301,43 @@ inline bool Foam::labelRange::found(const label value) const
 
 // * * * * * * * * * * * * * * * Member Operators  * * * * * * * * * * * * * //
 
-inline Foam::label Foam::labelRange::operator[](const label localIndex) const
+inline Foam::label Foam::labelRange::operator[]
+(
+    const label localIndex
+) const noexcept
 {
     return start_ + localIndex;
 }
 
 
-inline Foam::labelRange::const_iterator
+inline bool Foam::labelRange::operator()(const label value) const noexcept
-Foam::labelRange::operator()(const label localIndex) const
 {
-    return const_iterator(this, localIndex);
+    return found(value);
 }
 
 
-inline Foam::label Foam::labelRange::operator++()
+inline Foam::label Foam::labelRange::operator++() noexcept
 {
     return ++size_;
 }
 
 
-inline Foam::label Foam::labelRange::operator++(int)
+inline Foam::label Foam::labelRange::operator++(int) noexcept
 {
     return size_++;
 }
 
 
-inline Foam::label Foam::labelRange::operator--()
+inline Foam::label Foam::labelRange::operator--() noexcept
 {
     decrement();
     return size_;
 }
 
 
-inline Foam::label Foam::labelRange::operator--(int)
+inline Foam::label Foam::labelRange::operator--(int) noexcept
 {
-    const label old = size_;
+    const label old(size_);
     decrement();
     return old;
 }

src/surfMesh/surfZone/surfZone/surfZone.H

@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2011-2016 OpenFOAM Foundation
-     \\/     M anipulation  |
+     \\/     M anipulation  | Copyright (C) 2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -41,6 +41,7 @@ SourceFiles
 #include "label.H"
 #include "className.H"
 #include "surfZoneIdentifier.H"
+#include "labelRange.H"
 #include "autoPtr.H"
 #include "dictionary.H"
 
@@ -49,8 +50,7 @@ SourceFiles
 namespace Foam
 {
 
-// Forward declaration of friend functions and operators
+// Forward declarations
-
 class surfZone;
 
 Istream& operator>>(Istream&, surfZone&);
@@ -153,6 +153,12 @@ public:
             return size_;
         }
 
+        //- Return start/size range of this zone
+        labelRange range() const
+        {
+            return labelRange(start_, size_);
+        }
+
         //- Write
         void write(Ostream&) const;
 
@@ -175,6 +181,19 @@ public:
 };
 
 
+// Global Functions
+
+//- Get the labelRange for a surfZone
+template<>
+struct toLabelRange<surfZone>
+{
+    labelRange operator()(const surfZone& zone) const
+    {
+        return zone.range();
+    }
+};
+
+
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
 } // End namespace Foam