- name and functionality similar to std::unordered_map (C++17).
Formalizes what had been previously been implemented in IOobjectList
but now manages without pointer deletion/creation.
- clearer coding intent. Mark operator() as 'deprecated'
- add bounds checking to get(label) and set(label) methods.
This gives failsafe behaviour for get() that is symmetric with
HashPtrTable, autoPtr etc and aligns the set(label) methods
for UPtrList, PtrList and PtrDynList.
- use top-level PtrList::clone() instead of cloning individual elements
ENH: support HashPtrTable set with refPtr/tmp (flexibility)
- additional dummy template parameter to assist with supporting
derived classes. Currently just used for string types, but can be
extended.
- provide hash specialization for various integer types.
Removes the need for any forwarding.
- change default hasher for HashSet/HashTable from 'string::hash'
to `Hash<Key>`. This avoids questionable hashing calls and/or
avoids compiler resolution problems.
For example,
HashSet<label>::hasher and labelHashSet::hasher now both properly
map to Hash<label> whereas previously HashSet<label> would have
persistently mapped to string::hash, which was incorrect.
- standardize internal hashing functors.
Functor name is 'hasher', as per STL set/map and the OpenFOAM
HashSet/HashTable definitions.
Older code had a local templated name, which added unnecessary
clutter and the template parameter was always defaulted.
For example,
Old: `FixedList<label, 3>::Hash<>()`
New: `FixedList<label, 3>::hasher()`
Unchanged: `labelHashSet::hasher()`
Existing `Hash<>` functor namings are still supported,
but deprecated.
- define hasher and Hash specialization for bitSet and PackedList
- add symmetric hasher for 'face'.
Starts with lowest vertex value and walks in the direction
of the next lowest value. This ensures that the hash code is
independent of face orientation and face rotation.
NB:
- some of keys for multiphase handling (eg, phasePairKey)
still use yet another function naming: `hash` and `symmHash`.
This will be targeted for alignment in the future.
- handle binary/contiguous first as being the most obvious, followed
by increasing complexity of ascii.
Structure reading and writing routines similarly by introducing a
readList method to compliment the writeList method.
- using HashPtrTable::set() with the same key twice did not guarantee
proper cleanup of memory since it simply used the underlying
HashTable::set() without doing anything about the old memory. Now
check for pre-existing storage and delete it when it does not
correspond to the newly stored pointer.
This problem is independent of potential memory slicing previously
flagged (#1286) and only partially resolved.
- naming similarity with autoPtr, unique_ptr and other containers.
For UPtrList derivatives, this is equivalent to the existing
operator(). The read-only variant is also equivalent to the
single-parameter 'set(label)' method.
With PtrList<T> list(...) :
const T* ptr = list.get(10);
if (ptr)
{
ptr->method();
}
vs.
if (list.set(10))
{
list[10].method();
}
For HashPtrTable there is only a read-only variant which is equivalent
to testing for existence and for value.
With HashPtrTable<T> hash(...) :
const T* ptr = list.get("key");
if (ptr)
{
ptr->method();
}
vs.
if (list.found("key"))
{
// Fails on null pointer!!
list["key"].method();
}
Use of get() is largely a matter of taste or local coding requirements
- forwarding like the emplace() method, but overwriting existing
entries as required
- propagate similar changes to HashPtrTable
For example, with HashPtrTable<labelList> table(...) :
With 'insert' semantics
table.emplace("list1", 1000);
vs
if (!table.found("list1"))
{
table.set("list1", new labelList(1000));
}
or
table.insert("list1", autoPtr<labelList>::New(1000));
Note that the last example invokes an unnecessary allocation/deletion
if the insertion is unsuccessful.
With 'set' semantics:
table.emplace_set("list1", 15);
vs
table.set("list1", new labelList(15));
- relocate the pair_entry (HashTable) and unary_entry (HashSet) into
the Detail namespace and add output handling.
The output handling at this level removes the reliance on zero::null
output (HashSet) and allows direct support of pointers.
This means that the following now works
HashTable<T*> tbl;
os << tbl;
It also means that we don't need to overload operator<< for
HashPtrTable anymore.
- avoid delete/new when calling HashSet::set(). If the entry already
exists there is no reason to remove it and add another one with the
same content.
STYLE: HashTable iterators now have a val() method
- identical to the object() iterator method, but shorter to type.
- disallow insert() of raw pointers, since a failed insertion
(ie, entry already existed) results in an unmanaged pointer.
Either insert using an autoPtr, or set() with raw pointers or autoPtr.
- IOobjectList::add() now takes an autoPtr instead of an object reference
- IOobjectList::remove() now returns an autoPtr instead of a raw pointer
- support move construct/assignment for linked-lists themselves
and when moving into a 'normal' list
- better consistency with begin/end signatures and the various
iterators.
- for indirect linked-lists, provide iterator access to the underlying
data element address: iter.get() vs &(iter())
- add standard '->' indirection for iterators (as per normal STL
definitions)
- previously had a mismash of const/non-const attributes on iterators
that were confused with the attributes of the object being accessed.
- use the iterator keys() and object() methods consistently for all
internal access of the HashTable iterators. This makes the intention
clearer, the code easier to maintain, and protects against any
possible changes in the definition of the operators.
- 'operator*': The standard form expected by STL libraries.
However, for the std::map, this dereferences to a <key,value> pair,
whereas OpenFOAM dereferences simply to <value>.
- 'operator()': OpenFOAM treats this like the 'operator*'
- adjusted the values of end() and cend() to reinterpret from nullObject
instead of returning a static iteratorEnd() object.
This means that C++ templates can now correctly deduce and match
the return types from begin() and end() consistently.
So that range-based now works.
Eg,
HashTable<label> table1 = ...;
for (auto i : table1)
{
Info<< i << endl;
}
Since the 'operator*' returns hash table values, this prints all the
values in the table.
- it was possible to create a PackedList::iterator from a
PackedList::const_iterator and violate const-ness
- added HashTable::printInfo for emitting some information
- changed default table sizes from 100 -> 128 in preparation for future
2^n table sizes
