- provide key_iterator/const_key_iterator for all hashes,
reuse directly for HashSet as iterator/const_iterator, respectively.
- additional keys() method for HashTable that returns a wrapped to
a pair of begin/end const_iterators with additional size/empty
information that allows these to be used directly by anything else
expecting things with begin/end/size. Unfortunately does not yet
work with std::distance().
Example,
for (auto& k : labelHashTable.keys())
{
...
}
- explicitly mention the value-initialized status for the operator().
This means that the following code will properly use an initialized
zero.
HashTable<label> regionCount;
if (...)
regionCount("region1")++;
... and also this;
if (regionCount("something") > 0)
{
...
}
Note that the OpenFOAM HashTable uses operator[] to provide read and
write access to *existing* entries and will provoke a FatalError if
the entry does not exist.
The operator() provides write access to *existing* entries or will
create the new entry as required.
The STL hashes use operator[] for this purpose.
