updated xfer class

src/OpenFOAM/containers/Lists/CompactListList/CompactListList.C

@@ -93,9 +93,9 @@ CompactListList<T>::CompactListList(const UList<label>& rowSizes, const T& t)
 
 
 template<class T>
-CompactListList<T>::CompactListList(xfer<CompactListList<T> >& lst)
+CompactListList<T>::CompactListList(const xfer<CompactListList<T> >& lst)
 {
-    transfer(lst.ref());
+    transfer(*lst);
 }
 
 template<class T>

src/OpenFOAM/containers/Lists/CompactListList/CompactListList.H

@@ -104,7 +104,7 @@ public:
         CompactListList(const UList<label>& rowSizes, const T&);
 
         //- Construct by transferring the parameter contents
-        CompactListList(xfer<CompactListList<T> >&);
+        CompactListList(const xfer<CompactListList<T> >&);
 
         //- Construct as copy or re-use as specified.
         CompactListList(CompactListList<T>&, bool reUse);

src/OpenFOAM/containers/Lists/List/List.C

@@ -127,9 +127,9 @@ Foam::List<T>::List(const List<T>& a)
 
 // Construct by transferring the parameter contents
 template<class T>
-Foam::List<T>::List(xfer<List<T> >& lst)
+Foam::List<T>::List(const xfer<List<T> >& lst)
 {
-    transfer(lst.ref());
+    transfer(*lst);
 }
 
 

src/OpenFOAM/containers/Lists/List/List.H

@@ -95,7 +95,7 @@ public:
         List(const List<T>&);
 
         //- Construct by transferring the parameter contents
-        List(xfer<List<T> >&);
+        List(const xfer<List<T> >&);
 
         //- Construct as copy or re-use as specified.
         List(List<T>&, bool reUse);

src/OpenFOAM/containers/Lists/PackedList/PackedList.C

@@ -55,9 +55,9 @@ PackedList<nBits>::PackedList(const PackedList<nBits>& PList)
 
 
 template<int nBits>
-PackedList<nBits>::PackedList(xfer<PackedList<nBits> >& lst)
+PackedList<nBits>::PackedList(const xfer<PackedList<nBits> >& lst)
 {
-    transfer(lst.ref());
+    transfer(*lst);
 }
 
 

src/OpenFOAM/containers/Lists/PackedList/PackedList.H

@@ -135,7 +135,7 @@ public:
         PackedList(const PackedList<nBits>& PList);
 
         //- Construct by transferring the parameter contents
-        PackedList(xfer<PackedList<nBits> >&);
+        PackedList(const xfer<PackedList<nBits> >&);
 
         //- Construct from labelList.
         PackedList(const labelList&);

src/OpenFOAM/containers/Lists/PtrList/PtrList.C

@@ -72,9 +72,9 @@ Foam::PtrList<T>::PtrList(const PtrList<T>& a, const CloneArg& cloneArg)
 
 
 template<class T>
-Foam::PtrList<T>::PtrList(xfer<PtrList<T> >& lst)
+Foam::PtrList<T>::PtrList(const xfer<PtrList<T> >& lst)
 {
-    transfer(lst.ref());
+    transfer(*lst);
 }
 
 

src/OpenFOAM/containers/Lists/PtrList/PtrList.H

@@ -130,7 +130,7 @@ public:
         PtrList(const PtrList<T>&, const CloneArg&);
 
         //- Construct by transferring the parameter contents
-        PtrList(xfer<PtrList<T> >&);
+        PtrList(const xfer<PtrList<T> >&);
 
         //- Construct as copy or re-use as specified.
         PtrList(PtrList<T>&, bool reUse);

src/OpenFOAM/containers/Lists/UPtrList/UPtrList.C

@@ -51,9 +51,9 @@ UPtrList<T>::UPtrList(const label s)
 
 
 template<class T>
-UPtrList<T>::UPtrList(xfer<UPtrList<T> >& lst)
+UPtrList<T>::UPtrList(const xfer<UPtrList<T> >& lst)
 {
-    transfer(lst.ref());
+    transfer(*lst);
 }
 
 

src/OpenFOAM/containers/Lists/UPtrList/UPtrList.H

@@ -111,7 +111,7 @@ public:
         explicit UPtrList(const label);
 
         //- Construct by transferring the parameter contents
-        UPtrList(xfer<UPtrList<T> >&);
+        UPtrList(const xfer<UPtrList<T> >&);
 
         //- Construct as copy or re-use as specified.
         UPtrList(UPtrList<T>&, bool reUse);

src/OpenFOAM/containers/misc/xfer.H

@@ -26,11 +26,15 @@ Class
     Foam::xfer
 
 Description
-    A simple container for objects of type \<T\> that can be used for
-    transferring the contents rather than copying them.
+    A simple container that can be used to transfer the contents of objects
+    of type \<T\> of rather than copying them.
 
     The wrapped object of type \<T\> must implement a transfer() method.
 
+Note
+    The macro xferTmp(T,arg) can be used as a workaround for passing
+    temporaries to copy-constructors.
+
 SourceFiles
     xferI.H
 
@@ -44,18 +48,8 @@ SourceFiles
 namespace Foam
 {
 
-class Istream;
-class Ostream;
-
-// Forward declaration of friend functions and operators
-template<class T> class xfer;
-
-template<class T> Istream& operator>>(Istream&, xfer<T>&);
-template<class T> Ostream& operator<<(Ostream&, const xfer<T>&);
-
-
 /*---------------------------------------------------------------------------*\
-                         Class xfer Declaration
+                           Class xfer Declaration
 \*---------------------------------------------------------------------------*/
 
 template<class T>
@@ -63,81 +57,40 @@ class xfer
 {
     // Private data
 
-        //- Reference to the underlying datatype
-        T& ref_;
-
-    // Private Member Functions
-
-        //- Disallow default bitwise copy construct
-        xfer(const xfer<T>&);
-
-        //- Disallow default bitwise assignment
-        void operator=(const xfer<T>&);
+        //- Pointer to temporary object
+        mutable T* ptr_;
 
 public:
 
     // Constructors
 
-        //- Construct null, delaying the transfer to later
+        //- Null constructor, transfer later by assignment
         inline xfer();
 
-        //- Construct by transferring the parameter into this object
+        //- Construct by transferring the parameter contents into the object
         inline xfer(T&);
 
-        //- Construct by transferring the parameter into this object
-        inline xfer(xfer<T>&);
+        //- Construct by transferring the parameter contents into the object
+        inline xfer(const xfer<T>&);
 
     // Destructor
 
         inline ~xfer();
 
-    // Member Functions
-
-        //- Access to the underlying datatype
-        inline T& ref();
-
-        //- Transfer the contents of the parameter into this object
-        inline void transfer(T&);
-
-        //- Transfer the contents of the parameter into this object
-        inline void transfer(xfer<T>&);
-
-        //- Transfer the contents from this object to the parameter
-        inline void yield(T&);
-
-        //- Transfer the contents from this object to the parameter
-        inline void yield(xfer<T>&);
-
     // Member Operators
 
-        //- Transfer the contents into this object
+        //- Transfer the contents into the object
         inline void operator=(T&);
 
-        //- Transfer the contents into this object
-        inline void operator=(xfer<T>&);
+        //- Transfer the contents into the object
+        inline void operator=(const xfer<T>&);
 
         //- Return a non-const reference to const object
-        //  Useful for read-constructors where the argument is temporary
-        inline xfer<T>& operator()() const;
-
+        //  @sa xferTmp macro for an alternative for copy-constructors
+        inline const xfer<T>& operator()() const;
 
-    // Istream operator
-
-        //- Read from Istream, discarding current contents
-        friend Istream& operator>>
-        #ifndef __CINT__
-        <T>
-        #endif
-        (Istream&, xfer<T>&);
-
-    // Ostream operator
-
-        //- Write to Ostream
-        friend Ostream& operator<<
-        #ifndef __CINT__
-        <T>
-        #endif
-        (Ostream&, const xfer<T>&);
+        //- Reference to the underlying datatype
+        inline T& operator*() const;
 
 };
 
@@ -146,6 +99,27 @@ public:
 
 } // End namespace Foam
 
+/**
+ * @def xferTmp(T,arg)
+ * Construct a temporary and return a const reference to an xfer of
+ * type \<T\> and return a const reference.
+ *
+ * Useful for copy-constructors where the argument is temporary.
+ * This is a workaround for a template resolution problem.
+ *
+ * @par Example Use
+ * @code
+ *     List<label> a;
+ *     ...
+ *     List<label> b(xferTmp(List<label>, a));
+ *
+ * @endcode
+ * @sa xfer class
+*/
+
+#define xferTmp(T,arg) \
+    (static_cast<const Foam::xfer< T >&>(Foam::xfer< T >(arg)()))
+
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
 #include "xferI.H"

src/OpenFOAM/containers/misc/xferI.H

@@ -27,125 +27,71 @@ License
 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
 template<class T>
-Foam::xfer<T>::xfer()
+inline Foam::xfer<T>::xfer()
 :
-    ref_()
+    ptr_(new T)
 {}
 
 
 template<class T>
-Foam::xfer<T>::xfer(T& t)
+inline Foam::xfer<T>::xfer(T& t)
 :
-    ref_()
+    ptr_(new T)
 {
-    transfer(t);
+    ptr_->transfer(t);
 }
 
 
 template<class T>
-Foam::xfer<T>::xfer(xfer<T>& t)
+inline Foam::xfer<T>::xfer(const xfer<T>& t)
 :
-    ref_()
+    ptr_(new T)
 {
-    transfer(t);
+    ptr_->transfer(*(t.ptr_));
 }
 
 
-
 // * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
 
 template<class T>
-Foam::xfer<T>::~xfer()
-{}
-
-
-// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
-
-template<class T>
-T& Foam::xfer<T>::ref()
-{
-    return ref_;
-}
-
-
-template<class T>
-void Foam::xfer<T>::transfer(T& t)
+inline Foam::xfer<T>::~xfer()
 {
-    ref_.transfer(t);
-}
-
-
-template<class T>
-void Foam::xfer<T>::transfer(xfer<T>& t)
-{
-    ref_.transfer(t.ref_);
-}
-
-
-template<class T>
-void Foam::xfer<T>::yield(T& t)
-{
-    t.transfer(ref_);
-}
-
-
-template<class T>
-void Foam::xfer<T>::yield(xfer<T>& t)
-{
-    t.ref_.transfer(ref_);
+    delete ptr_;
+    ptr_ = 0;
 }
 
 
 // * * * * * * * * * * * * * * * Member Operators  * * * * * * * * * * * * * //
 
-
 template<class T>
-void Foam::xfer<T>::operator=(T& t)
+inline void Foam::xfer<T>::operator=(T& t)
 {
-    transfer(t);
+    ptr_->transfer(t);
 }
 
 
 template<class T>
-void Foam::xfer<T>::operator=(xfer<T>& t)
+inline void Foam::xfer<T>::operator=(const xfer<T>& t)
 {
-    if (this == &t)
+    // silently ignore copy to self
+    if (this != &t)
     {
-        FatalErrorIn
-        (
-            "Foam::xfer<T>::operator="
-            "(const Foam::xfer<T>&)"
-        )   << "Attempted assignment to self"
-            << abort(FatalError);
+        ptr_->transfer(*(t.ptr_));
     }
-
-    transfer(t);
-}
-
-
-template<class T>
-Foam::xfer<T>& Foam::xfer<T>::operator()() const
-{
-    return const_cast<xfer<T>&>(*this);
 }
 
 
-
-// * * * * * * * * * * * * * * * Friend Operators  * * * * * * * * * * * * * //
-
 template<class T>
-Foam::Istream& Foam::operator>>(Istream& is, xfer<T>& t)
+inline const Foam::xfer<T>& Foam::xfer<T>::operator()() const
 {
-    is >> t.ref_;
-    return is;
+    return *this;
 }
 
 
 template<class T>
-Foam::Ostream& Foam::operator<<(Ostream& os, const xfer<T>& t)
+inline T& Foam::xfer<T>::operator*() const
 {
-    os << t.ref_;
-    return os;
+    return *ptr_;
 }
 
 // ************************************************************************* //