HashPtrTable.H

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/*---------------------------------------------------------------------------*\
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-------------------------------------------------------------------------------
    Copyright (C) 2011-2016 OpenFOAM Foundation
    Copyright (C) 2017-2025 OpenCFD Ltd.
-------------------------------------------------------------------------------
License
    This file is part of OpenFOAM.

    OpenFOAM is free software: you can redistribute it and/or modify it
    under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    for more details.

    You should have received a copy of the GNU General Public License
    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.

Class
    Foam::HashPtrTable

Description
    A HashTable of pointers to objects of type <T>,
    with deallocation management of the pointers.

SourceFiles
    HashPtrTable.C
    HashPtrTableI.H
    HashPtrTableIO.C

\*---------------------------------------------------------------------------*/

#ifndef Foam_HashPtrTable_H
#define Foam_HashPtrTable_H

#include "HashTable.H"
#include <memory>

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

namespace Foam
{

// Forward Declarations
template<class T> class autoPtr;
template<class T> class refPtr;
template<class T> class tmp;
template<class T, class Key, class Hash> class HashPtrTable;

template<class T, class Key, class Hash>
Istream& operator>>(Istream& is, HashPtrTable<T, Key, Hash>& tbl);


/*---------------------------------------------------------------------------*\
                        Class HashPtrTable Declaration
\*---------------------------------------------------------------------------*/

template<class T, class Key=word, class Hash=Foam::Hash<Key>>
class HashPtrTable
:
    public HashTable<T*, Key, Hash>
{
    // Private Member Functions

        //- Read from Istream using Istream constructor class
        template<class INew>
        void readIstream(Istream& is, const INew& inew);

        //- Read from dictionary using Istream constructor class
        template<class INew>
        void read(const dictionary& dict, const INew& inew);

        //- Implementation for emplace_set and try_emplace
        template<class... Args>
        inline T& emplaceImpl
        (
            const bool overwrite,
            const Key& key,
            Args&&... args
        );

public:

    //- The template instance used for this table
    typedef HashPtrTable<T, Key, Hash> this_type;

    //- The template instance used for the parent HashTable
    typedef HashTable<T*, Key, Hash> parent_type;

    using iterator = typename parent_type::iterator;
    using const_iterator = typename parent_type::const_iterator;


    // Constructors

        //- Default construct: empty without allocation (capacity=0)
        constexpr HashPtrTable() noexcept = default;

        //- Construct empty without allocation (capacity=0)
        explicit constexpr HashPtrTable(Foam::zero) noexcept : this_type() {}

        //- Construct given initial table capacity
        explicit HashPtrTable(const label initialCapacity)
        :
            parent_type(initialCapacity)
        {}

        //- Copy construct, making a copy of each element
        HashPtrTable(const this_type& rhs);

        //- Move construct
        HashPtrTable(this_type&& rhs) noexcept
        :
            parent_type(std::move(rhs))
        {}

        //- Construct from Istream using given Istream constructor class
        template<class INew>
        HashPtrTable(Istream& is, const INew& inew);

        //- Construct from Istream using default Istream constructor class
        HashPtrTable(Istream& is);

        //- Construct from dictionary with default dictionary constructor class
        explicit HashPtrTable(const dictionary& dict);


    //- Destructor
    ~HashPtrTable();


    // Member Functions

    // Access

        //- Return const pointer associated with given entry or a nullptr
        //- if the key does not exist in the table.
        inline const T* test(const Key& key) const;

        //- Return const pointer associated with given entry or a nullptr
        //- if the key does not exist in the table.
        inline const T* get(const Key& key) const;


    // Edit

        //- Release ownership of the pointer and replace with a nullptr
        //  Includes a safeguard against the end-iterator.
        //
        //  \return the entry's old value as an encapsulated pointer.
        autoPtr<T> release(iterator& iter);

        //- Release ownership of the pointer and replace with a nullptr
        //
        //  \return the entry's old value as an encapsulated pointer.
        autoPtr<T> release(const Key& key);

        //- Remove entry specified by given iterator.
        //  Includes a safeguard against the end-iterator.
        //
        //  \return the entry's old value as an encapsulated pointer.
        autoPtr<T> remove(iterator& iter);

        //- Remove entry specified by given key.
        //
        //  \return the entry's old value as an encapsulated pointer.
        autoPtr<T> remove(const Key& key);

        //- Erase entry specified by given iterator and delete the
        //- allocated pointer.
        //  Includes a safeguard against the end-iterator.
        //
        //  \return True if item was removed
        bool erase(iterator& iter);

        //- Erase entry specified by given key and delete the
        //- allocated pointer.
        //
        //  \return True if item was removed
        bool erase(const Key& key);

        //- Clear all entries from table and delete any allocated pointers
        void clear();

        //- Attempts to extract entries from source parameter and insert them
        //- into \c this, does not overwrite existing entries.
        //- The source will contains any items that could not be merged.
        void merge(HashPtrTable<T, Key, Hash>& source);

        //- Attempts to extract entries from source parameter and insert them
        //- into \c this, does not overwrite existing entries.
        //- The source will contains any items that could not be merged.
        void merge(HashPtrTable<T, Key, Hash>&& source);


    // Reading/writing

        //- Invoke write() on each non-null entry
        void write(Ostream& os) const;


    // Member Operators

        //- Copy assignment
        void operator=(const this_type& rhs);

        //- Move assignment
        void operator=(this_type&& rhs);


    // IOstream Operators

        //- Clear table and read from Istream
        friend Istream& operator>> <T, Key, Hash>
        (
            Istream& is,
            HashPtrTable<T, Key, Hash>& tbl
        );


    // Override HashTable methods

        //- Emplace insert a new entry, not overwriting existing entries.
        //  \return True if the entry did not previously exist in the table.
        template<class... Args>
        inline bool emplace(const Key& key, Args&&... args);

        //- Emplace set an entry, overwriting any existing entries.
        //  \return Reference to the new element.
        template<class... Args>
        inline T& emplace_set(const Key& key, Args&&... args);

        //- Like emplace_set() but will not overwrite an occupied (non-null)
        //- location.
        //  \param key - the location to set (unless already defined)
        //  \param args arguments to forward to the constructor of the element
        //  \return reference to the existing or the new element.
        template<class... Args>
        inline T& try_emplace(const Key& key, Args&&... args);

        //- No insert() with raw pointers (potential memory leaks).
        //- Use insert() with autoPtr or set()
        inline bool insert(const Key&, T*) = delete;

        //- Insert a new entry, not overwriting existing entries.
        //  \return True if the entry inserted (not previously in table)
        inline bool insert(const Key& key, std::unique_ptr<T>&& ptr);

        //- Insert a new entry, not overwriting existing entries.
        //  \return True if the entry inserted (not previously in table)
        inline bool insert(const Key& key, autoPtr<T>&& ptr);

        //- Assign a new entry, overwrites existing
        inline bool set(const Key& key, T* ptr);

        //- Assign a new entry, overwrites existing
        inline bool set(const Key& key, std::unique_ptr<T>&& ptr);

        //- Assign a new entry, overwrites existing
        inline bool set(const Key& key, autoPtr<T>&& ptr);

        //- Assign a new entry from refPtr (move or clone), overwrites existing
        inline bool set(const Key& key, const refPtr<T>& ptr);

        //- Assign a new entry from tmp (move or clone), overwrites existing
        inline bool set(const Key& key, const tmp<T>& ptr);


    // Housekeeping

        //- Insert a new entry, not overwriting existing entries.
        //  \return True if the entry inserted (not previously in table)
        bool insert(const Key& key, autoPtr<T>& ptr)
        {
            return this->insert(key, std::move(ptr));
        }

        //- Assign a new entry, overwrites existing
        bool set(const Key& key, autoPtr<T>& ptr)
        {
            return this->set(key, std::move(ptr));
        }
};


// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

} // End namespace Foam

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

#include "HashPtrTableI.H"

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

#ifdef NoRepository
    #include "HashPtrTable.C"
#endif

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

#endif

// ************************************************************************* //