Commit Graph

14 Commits

Author SHA1 Message Date
Mark Olesen
cf889306d0 ENH: added HashTable count, filter and generalized toc methods
- Generalized means over filtering table entries based on their keys,
  values, or both.  Either filter (retain), or optionally prune elements
  that satisfy the specified predicate.

  filterKeys and filterValues:
  - Take a unary predicate with the signature

        bool operator()(const Key& k);

  - filterEntries:
    Takes a binary predicate with the signature

        bool operator()(const Key& k, const T& v);

==

  The predicates can be normal class methods, or provide on-the-fly
  using a C++ lambda. For example,

      wordRes goodFields = ...;
      allFieldNames.filterKeys
      (
          [&goodFields](const word& k){ return goodFields.match(k); }
      );

  Note that all classes that can match a string (eg, regExp, keyType,
  wordRe, wordRes) or that are derived from a Foam::string (eg, fileName,
  word) are provided with a corresponding

      bool operator()(const std::string&)

  that either performs a regular expression or a literal match.
  This allows such objects to be used directly as a unary predicate
  when filtering any string hash keys.

  Note that HashSet and hashedWordList both have the proper
  operator() methods that also allow them to be used as a unary
  predicate.

- Similar predicate selection with the following:
    * tocKeys, tocValues, tocEntries
    * countKeys, countValues, countEntries

  except that instead of pruning, there is a simple logic inversion.
2017-05-17 10:18:14 +02:00
Mark Olesen
4b0d1632b6 BUG: hashtable key_iterator ++ operator returning incorrect type
ENH: ensure std::distance works with hashtable iterators
2017-05-14 16:58:47 +02:00
Mark Olesen
f73b5b629f ENH: added HashTable 'lookup' and 'retain' methods
- 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.
2017-05-11 12:25:35 +02:00
Mark Olesen
03d180724b ENH: improve HashTable iterator access and management
- 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())
     {
        ...
     }
2017-05-04 10:17:18 +02:00
Mark Olesen
c0a50dc621 ENH: improve overall consistency of the HashTable and its iterators
- 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.
2017-05-02 00:15:12 +02:00
Mark Olesen
c65e2e580d ENH: add some standard templates and macros into stdFoam.H
- some functionality similar to what the standary library <iterator>
  provides.

  * stdFoam::begin() and stdFoam::end() do type deduction,
    which means that many cases it is possible to manage these types
    of changes.

    For example, when managing a number of indices:
       Map<labelHashSet> lookup;

    1) Longhand:

        for
        (
            Map<labelHashSet>::const_iterator iter = lookup.begin();
            iter != lookup.end();
            ++iter
        )
        { .... }

    1b) The same, but wrapped via a macro:

        forAllConstIter(Map<labelHashSet>, lookup, iter)
        { .... }

    2) Using stdFoam begin/end templates directly

        for
        (
            auto iter = stdFoam::begin(lookup);
            iter != stdFoam::end(lookup);
            ++iter
        )
        { .... }

    2b) The same, but wrapped via a macro:

        forAllConstIters(lookup, iter)
        { .... }

Note that in many cases it is possible to simply use a range-based for.
Eg,
     labelList myList;

     for (auto val : myList)
     { ... }

     for (const auto& val : myList)
     { ... }

These however will not work with any of the OpenFOAM hash-tables,
since the standard C++ concept of an iterator would return a key,value
pair when deferencing the *iter.

The deduction methods also exhibits some slightly odd behaviour with
some PtrLists (needs some more investigation).
2017-04-29 22:28:16 +02:00
Mark Olesen
de5688e095 ENH: expose HashTable iterator object() methods
- to the referenced object via a method name, which may be clearer
  than deferencing the iterator

     [key, value] =>  iter.key(), *iter
     [key, value] =>  iter.key(), iter()
     [key, value] =>  iter.key(), iter.object()
2017-01-26 18:11:02 +01:00
Henry Weller
900c804bf0 HashTable: Added void operator=(std::initializer_list<Tuple2<Key, T>>) 2016-08-11 21:41:55 +01:00
Henry Weller
076c4c6e82 HashTable: Added C++11 initializer_list constructor
e.g.
    HashTable<label, string> table1
    {
        {"kjhk", 10},
        {"kjhk2", 12}
    };

    HashTable<label, label, Hash<label>> table2
    {
        {3, 10},
        {5, 12},
        {7, 16}
    };
2016-08-05 22:30:26 +01:00
Henry
c2dd153a14 Copyright transfered to the OpenFOAM Foundation 2011-08-14 12:17:30 +01:00
andy
eaef8d482b STYLE: Updated 1991 start copyright year to 2004 2011-01-14 16:08:00 +00:00
andy
099cc39e2e Revert "STYLE: 2011 copyright date."
This reverts commit b18f6cc1ce.
2011-01-05 18:24:29 +00:00
graham
b18f6cc1ce STYLE: 2011 copyright date. 2011-01-05 11:14:26 +00:00
Mark Olesen
499d48cfdb STYLE: uniform 'Test-' prefix for all applications/test
- easier to clean, avoid confusion with 'real' applications, etc.
2010-11-23 16:26:04 +01:00