- the null output adapter was previously used for the HashTables API
when HashSet actually stored key/value. Now that the node only
contains the key, having suppressed output is redundant, as is the
zero::null class (reduces clutter)
STYLE: replace one::minus dispatch in extendedEdgeMesh
GIT: remove Foam::nil typedef (deprecated since May-2017)
- 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.
- 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.
- unfriend HashSet, HashTable IO operators
- global min(), max(), minMax() functions taking a labelHashSet and an
optional limit. For example,
labelHashSet set = ...;
Info<< "min is " << min(set) << nl;
Info<< "max (non-negative) " << max(set, 0) << nl;
- make HashTable iterator '->' dereferencing more consistent by also
supporting non-pointer types as well.
- read HashTable values in-situ to avoid copying
- can be used as a more natural test on the iterator.
For example, with
HashTable<..> table;
auto iter = table.find(...);
Following are now all equivalent:
1. if (iter != table.end()) ...
2. if (iter.found()) ...
3. if (iter) ...
- improves backward compatibility and more naming consistency.
Retain setMany(iter1, iter2) to avoid ambiguity with the
PackedList::set(index, value) method.
- relocated HashSetPlusEqOp and HashTablePlusEqOp to
HashSetOps::plusEqOp and HashTableOps::plusEqOp, respectively
- additional functions for converting between a labelHashSet
and a PackedBoolList or List<bool>:
From lists selections to labelHashSet indices:
HashSetOps::used(const PackedBoolList&);
HashSetOps::used(const UList<bool>&);
From labelHashSet to list forms:
PackedBoolList bitset(const labelHashSet&);
List<bool> bools(const labelHashSet&);
- Eg instead of using labelHashSet, used HashSet<label> which uses
the string::hash for hashing. Other places inadvertently using the
string::hash instead of Hash<label> for hashing.
STYLE: use Map<..> instead of HashTable<.., label, Hash<label>>
- reduces clutter
- the zero::null and one::null sub-classes add an additional null
output adapter.
The function of the nil class (special-purpose class only used for
HashSet) is now taken by zero::null.
- improve functional compatibility with DynList (remove methods)
* eg, remove an element from any position in a DynamicList
* reduce the number of template parameters
* remove/subset regions of DynamicList
- propagate Swap template specializations for lists, hashtables
- move construct/assignment to various containers.
- add find/found methods for FixedList and UList for a more succinct
(and clearer?) usage than the equivalent global findIndex() function.
- simplify List_FOR_ALL loops
- lookup(): with a default value (const access)
For example,
Map<label> something;
value = something.lookup(key, -1);
being equivalent to the following:
Map<label> something;
value = -1; // bad value
if (something.found(key))
{
value = something[key];
}
except that lookup also makes it convenient to handle const references.
Eg,
const labelList& ids = someHash.lookup(key, labelList());
- For consistency, provide a two parameter HashTable '()' operator.
The lookup() method is, however, normally preferable when
const-only access is to be ensured.
- retain(): the counterpart to erase(), it only retains entries
corresponding to the listed keys.
For example,
HashTable<someType> largeCache;
wordHashSet preserve = ...;
largeCache.retain(preserve);
being roughly equivalent to the following two-stage process,
but with reduced overhead and typing, and fewer potential mistakes.
HashTable<someType> largeCache;
wordHashSet preserve = ...;
{
wordHashSet cull(largeCache.toc()); // all keys
cull.erase(preserve); // except those to preserve
largeCache.erase(cull); //
}
The HashSet &= operator and retain() are functionally equivalent,
but retain() also works with dissimilar value types.
- 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())
{
...
}
- make construct from UList explicit and provide corresponding
assignment operator.
- add construct,insert,set,assignment from FixedList.
This is convenient when dealing with things like edges or triFaces.
- 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.
- makes it easier to use as a wordHashSet replacement for situations
where we want to avoid duplicates but retain the input order.
- support construction from HashTable, which means it works like the
HashTable::sortedToc but with its own hashing for these keys.
- expose rehash() method for the user. There is normally no need for
using it directly, but also no reason to lock it away as private.
DynamicList
-----------
- construction, assignment and append
HashSet
-------
- construction, insert, set.
- assignment will use the implicit List constructor
hashedWordList
--------------
- construction, assignment
- additional sort() and uniq() methods.
- Readonly access to HashTable information via lookup() method.
- NB: could avoid 'const char**' constructors in the future
- operator+= : add in the listed keys
- operator-= : remove the listed keys
- operator&= : intersection of keys
- added xfer constructor (just in case)
- moved labelHashSet typedef to HashSet.H, for consistency with the
wordHashSet typedef being there and since it is used so often
