template<class T>
class Foam::Xfer< T >
A simple container for copying or transferring objects of type <T>.
The wrapped object of type <T> must implement a transfer() method and an operator=() copy method.
Since it is decided upon construction of the Xfer object whether the parameter is to be copied or transferred, the contents of the resulting Xfer object can be transferred unconditionally. This greatly simplifies defining constructors or methods in other classes with mixed transfer/copy semantics without requiring 2^N different versions.
When transferring between dissimilar types, the xferCopyTo() and xferMoveTo() functions can prove useful. An example is transferring from a DynamicList to a List. Since the List<T>::transfer(List<T>&) method could result in some allocated memory becoming inaccessible, the xferMoveTo() function should be used to invoke the correct List<T>::transfer(DynamicList<T>&) method.
DynamicList<label> dynLst;
...
labelList plainLst( xferMoveTo<labelList>(dynLst) );
Of course, since this example is a very common operation, the DynamicList::xfer() method transfers to a plain List anyhow. It would thus be simpler (and clearer) just to use the following code:
DynamicList<label> dynLst;
...
labelList plainLst(dynLst.xfer());
- See also
- xferCopy, xferCopyTo, xferMove, xferMoveTo, xferTmp
- Source files
-
Definition at line 85 of file Xfer.H.
1.8.13
