ENH: support UList[labelRange] and SubList construction with labelRange

This uses a concept similar to what std::valarray and std::slice do.
A labelRange provides a convenient container for holding start/size
and lends itself to addressing 'sliced' views of lists.
For safety, the operations and constructors restricts the given input range
to a valid addressible region of the underlying list, while the labelRange
itself precludes negative sizes.

The SubList version is useful for patches or other things that have a
SubList as its parameter. Otherwise the UList [] operator will be the
more natural solution. The slices can be done with a labelRange, or
a {start,size} pair.

Examples,
     labelList list1 = identity(20);

     list1[labelRange(18,10)]  = -1;
     list1[{-20,25}] = -2;
     list1[{1000,5}] = -3;

     const labelList list2 = identity(20);
     list2[{5,10}] = -3;  // ERROR: cannot assign to const!

applications/test/List/Test-List.C

@@ -76,7 +76,6 @@ int main(int argc, char *argv[])
         Info<<"is >>: " << intlist << endl;
     }
 
-
     List<vector> list1(IStringStream("1 ((0 1 2))")());
     Info<< "list1: " << list1 << endl;
 
@@ -150,7 +149,6 @@ int main(int argc, char *argv[])
         Info<< "normal: " << longLabelList << nl;
         Info<< "flatOutput: " << flatOutput(longLabelList) << nl;
         // Info<< "flatOutput(14): " << flatOutput(longLabelList, 14) << nl;
-        // Info<< "flatOutput(15): " << flatOutput(longLabelList, 15) << nl;
 
         stringList longStringList(12);
         forAll(longStringList, i)
@@ -165,6 +163,66 @@ int main(int argc, char *argv[])
         // contiguous longStringList[i].resize(3, 'a' + i);
     }
 
+    // test SubList and labelRange
+    {
+        Info<< nl;
+        labelList longLabelList = identity(25);
+        reverse(longLabelList);
+
+        FixedList<label, 6> fixedLabelList{0,1,2,3,4,5};
+        const labelList constLabelList = identity(25);
+
+        Info<< "full-list: " << flatOutput(longLabelList) << nl;
+
+        labelRange range1(-15, 25);
+        Info<<"sub range:" << range1 << "=";
+        Info<< SubList<label>(longLabelList, range1) << nl;
+
+        labelRange range2(7, 8);
+        Info<<"sub range:" << range2 << "=";
+        Info<< SubList<label>(longLabelList, range2) << nl;
+
+        // labelRange range2(7, 8);
+        Info<<"use range " << range2 << " to set value";
+        SubList<label>(longLabelList, range2) = -15;
+        Info<< "=> " << flatOutput(longLabelList) << nl;
+
+        // This syntax looks even nicer:
+
+        // GOOD: does not compile
+        // > constLabelList[labelRange(23,5)] = 5;
+
+        // Check correct overlaps
+        longLabelList[labelRange(-10, 12)] = 200;
+        longLabelList[{18,3}] = 100;
+        longLabelList[{23,3}] = 400;
+        // and complete misses
+        longLabelList[{500,50}] = 100;
+
+        // labelRange automatically suppresses -ve size -> nop
+        longLabelList[{5,-5}] = 42;
+        longLabelList[{21,100}] = 42;
+
+        //Good: does not compile
+        //> longLabelList[labelRange(20,50)] = constLabelList;
+
+        //Good: does not compile
+        // longLabelList[labelRange(20,50)] = fixedLabelList;
+
+        Info<< "updated: " << constLabelList[labelRange(23,5)] << nl;
+        Info<< "updated: " << flatOutput(longLabelList) << nl;
+
+        //Nope: sort(longLabelList[labelRange(18,5)]);
+        {
+            // Instead
+            UList<label> sub = longLabelList[labelRange(0, 8)];
+            sort(sub);
+        }
+        Info<< "sub-sorted: " << flatOutput(longLabelList) << nl;
+
+        // Info<<"Slice=" << longLabelList[labelRange(23,5)] << nl;
+    }
+
     wordReList reLst;
     wordList wLst;
     stringList sLst;

src/OpenFOAM/containers/Lists/SubList/SubList.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) 2017 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -40,6 +40,7 @@ SourceFiles
 #define SubList_H
 
 #include "List.H"
+#include "labelRange.H"
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
@@ -55,7 +56,6 @@ class SubList
 :
     public UList<T>
 {
-
 public:
 
     // Static Member Functions
@@ -81,6 +81,23 @@ public:
             const label startIndex
         );
 
+        //- Construct from UList and a (start,size) range.
+        //  The range is subsetted with the list size itself to ensure that the
+        //  result always addresses a valid section of the list.
+        inline SubList
+        (
+            const UList<T>& list,
+            const labelRange& range
+        );
+
+        //- Construct from UList and a (start,size) range, but bypassing
+        //  run-time range checking.
+        inline SubList
+        (
+            const labelRange& range,
+            const UList<T>& list
+        );
+
 
     // Member operators
 
@@ -88,13 +105,13 @@ public:
         inline operator const Foam::List<T>&() const;
 
         //- Assignment of all entries to the given sub-list
-        inline void operator=(const SubList<T>&);
+        inline void operator=(const SubList<T>& list);
 
         //- Assignment of all entries to the given list
-        inline void operator=(const UList<T>&);
+        inline void operator=(const UList<T>& list);
 
         //- Assignment of all entries to the given value
-        inline void operator=(const T&);
+        inline void operator=(const T& t);
 };
 
 

src/OpenFOAM/containers/Lists/SubList/SubListI.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) 2017 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -51,7 +51,6 @@ inline Foam::SubList<T>::SubList
     UList<T>(&(list.v_[startIndex]), subSize)
 {
     #ifdef FULLDEBUG
-
     // Artificially allow the start of a zero-sized subList to be
     // one past the end of the original list.
     if (subSize)
@@ -69,6 +68,28 @@ inline Foam::SubList<T>::SubList
 }
 
 
+template<class T>
+inline Foam::SubList<T>::SubList
+(
+    const UList<T>& list,
+    const labelRange& range
+)
+:
+    SubList<T>(list.validateRange(range), list)
+{}
+
+
+template<class T>
+inline Foam::SubList<T>::SubList
+(
+    const labelRange& range,
+    const UList<T>& list
+)
+:
+    SubList<T>(list, range.size(), range.start())
+{}
+
+
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
 template<class T>
@@ -88,16 +109,16 @@ inline Foam::SubList<T>::operator const Foam::List<T>&() const
 
 
 template<class T>
-inline void Foam::SubList<T>::operator=(const SubList<T>& sl)
+inline void Foam::SubList<T>::operator=(const SubList<T>& list)
 {
-    UList<T>::deepCopy(sl);
+    UList<T>::deepCopy(list);
 }
 
 
 template<class T>
-inline void Foam::SubList<T>::operator=(const UList<T>& l)
+inline void Foam::SubList<T>::operator=(const UList<T>& list)
 {
-    UList<T>::deepCopy(l);
+    UList<T>::deepCopy(list);
 }
 
 

src/OpenFOAM/containers/Lists/UList/UList.C

@@ -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) 2017 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -26,9 +26,49 @@ License
 #include "UList.H"
 #include "ListLoopM.H"
 #include "contiguous.H"
+#include "labelRange.H"
 
 #include <algorithm>
 
+// * * * * * * * * * * * * Protected Member Functions  * * * * * * * * * * * //
+
+template<class T>
+Foam::labelRange Foam::UList<T>::validateRange(const labelRange& range) const
+{
+    const labelRange slice = range.subset(0, this->size());
+
+    #ifdef FULLDEBUG
+    this->checkStart(slice.start());
+    this->checkSize(slice.start() + slice.size());
+    #endif
+
+    return slice;
+}
+
+
+template<class T>
+Foam::labelRange Foam::UList<T>::validateRange
+(
+    std::initializer_list<label> start_size_pair
+) const
+{
+    if (start_size_pair.size() != 2)
+    {
+        FatalErrorInFunction
+            << "range specified with " << start_size_pair.size()
+            << " elements instead of 2"
+            << abort(FatalError);
+    }
+
+    auto iter = start_size_pair.begin();
+
+    const label beg = *(iter++);
+    const label sz  = *iter;
+
+    return this->validateRange(labelRange(beg, sz));
+}
+
+
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
 template<class T>
@@ -64,6 +104,47 @@ void Foam::UList<T>::deepCopy(const UList<T>& a)
 
 // * * * * * * * * * * * * * * * Member Operators  * * * * * * * * * * * * * //
 
+template<class T>
+Foam::UList<T> Foam::UList<T>::operator[](const labelRange& range)
+{
+    const labelRange slice = validateRange(range);
+
+    return UList<T>(&(this->v_[slice.start()]), slice.size()); // SubList
+}
+
+template<class T>
+const Foam::UList<T> Foam::UList<T>::operator[](const labelRange& range) const
+{
+    const labelRange slice = validateRange(range);
+
+    return UList<T>(&(this->v_[slice.start()]), slice.size()); // SubList
+}
+
+
+template<class T>
+Foam::UList<T> Foam::UList<T>::operator[]
+(
+    std::initializer_list<label> start_size_pair
+)
+{
+    const labelRange slice = validateRange(start_size_pair);
+
+    return UList<T>(&(this->v_[slice.start()]), slice.size()); // SubList
+}
+
+template<class T>
+const Foam::UList<T> Foam::UList<T>::operator[]
+(
+    std::initializer_list<label> start_size_range
+) const
+{
+    // Restricted range
+    const labelRange slice = validateRange(start_size_range);
+
+    return UList<T>(&(this->v_[slice.start()]), slice.size()); // SubList
+}
+
+
 template<class T>
 void Foam::UList<T>::operator=(const T& t)
 {

src/OpenFOAM/containers/Lists/UList/UList.H

@@ -48,13 +48,15 @@ SourceFiles
 #include "nullObject.H"
 #include "zero.H"
 #include "stdFoam.H"
+#include <initializer_list>
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
 namespace Foam
 {
 
-// Forward declaration of friend classes
+// Forward declarations
+class labelRange;
 template<class T> class List;
 template<class T> class SubList;
 
@@ -101,6 +103,16 @@ protected:
         //- Write the UList with its compound type
         void writeEntry(Ostream& os) const;
 
+        //- Return a validated (start,size) subset range, which means that it
+        //  always addresses a valid section of the list.
+        labelRange validateRange(const labelRange& range) const;
+
+        //- Return a validated (start,size) subset range, which means that it
+        //  always addresses a valid section of the list.
+        labelRange validateRange
+        (
+            std::initializer_list<label> start_size_pair
+        ) const;
 
 public:
 
@@ -239,6 +251,29 @@ public:
         //  an out-of-range element returns false without any ill-effects
         inline const T& operator[](const label i) const;
 
+        //- Return (start,size) subset from UList with non-const access.
+        //  The range is subsetted with the list size itself to ensure that the
+        //  result always addresses a valid section of the list.
+        UList<T> operator[](const labelRange& range);
+
+        //- Return (start,size) subset from UList with const access.
+        //  The range is subsetted with the list size itself to ensure that the
+        //  result always addresses a valid section of the list.
+        const UList<T> operator[](const labelRange& range) const;
+
+        //- Return (start,size) subset from UList with non-const access.
+        //  The range is subsetted with the list size itself to ensure that the
+        //  result always addresses a valid section of the list.
+        UList<T> operator[](std::initializer_list<label> start_size_range);
+
+        //- Return (start,size) subset from UList with const access.
+        //  The range is subsetted with the list size itself to ensure that the
+        //  result always addresses a valid section of the list.
+        const UList<T> operator[]
+        (
+            std::initializer_list<label> start_size_range
+        ) const;
+
         //- Allow cast to a const List<T>&
         inline operator const Foam::List<T>&() const;
 

src/OpenFOAM/containers/Lists/UList/UListI.H

@@ -162,7 +162,6 @@ inline void Foam::UList<T>::shallowCopy(const UList<T>& a)
 
 // * * * * * * * * * * * * * * * Member Operators  * * * * * * * * * * * * * //
 
-
 template<class T>
 inline T& Foam::UList<T>::operator[](const label i)
 {
@@ -172,7 +171,6 @@ inline T& Foam::UList<T>::operator[](const label i)
     return v_[i];
 }
 
-
 namespace Foam
 {
     // Template specialization for bool
@@ -191,7 +189,6 @@ namespace Foam
     }
 }
 
-
 template<class T>
 inline const T& Foam::UList<T>::operator[](const label i) const
 {