/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     |
    \\  /    A nd           | Copyright (C) 2011-2016 OpenFOAM Foundation
     \\/     M anipulation  | Copyright (C) 2016-2017 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::HashSet

Description
    A HashTable with keys but without contents.

Typedef
    Foam::wordHashSet

Description
    A HashSet with (the default) word keys.

Typedef
    Foam::labelHashSet

Description
    A HashSet with label keys.

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

#ifndef HashSet_H
#define HashSet_H

#include "HashTable.H"
#include "nil.H"

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

namespace Foam
{

// Forward declaration of friend functions and operators
template<class Key, class Hash> class HashSet;

template<class Key, class Hash>
Ostream& operator<<(Ostream& os, const HashSet<Key, Hash>& tbl);


/*---------------------------------------------------------------------------*\
                           Class HashSet Declaration
\*---------------------------------------------------------------------------*/

template<class Key=word, class Hash=string::hash>
class HashSet
:
    public HashTable<nil, Key, Hash>
{
    // Private Member Functions

        //- Insert values, using begin/end iterators.
        template<class InputIter>
        inline label insertMultiple
        (
            const InputIter begIter,
            const InputIter endIter
        );

        //- Assign using begin/end iterators.
        template<class InputIter>
        inline label assignMultiple
        (
            const InputIter begIter,
            const InputIter endIter,
            const label sz
        );


public:

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

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

    //- An iterator, returning reference to the key
    using iterator = typename parent_type::key_iterator;

    //- A const_iterator, returning reference to the key
    using const_iterator = typename parent_type::const_key_iterator;


    // Constructors

        //- Construct given initial size
        HashSet(const label size = 128)
        :
            parent_type(size)
        {}

        //- Construct from Istream
        HashSet(Istream& is)
        :
            parent_type(is)
        {}

        //- Construct from UList of Key
        explicit HashSet(const UList<Key>& lst);

        //- Construct from FixedList of Key
        template<unsigned Size>
        explicit HashSet(const FixedList<Key, Size>& lst);

        //- Construct from an initializer list of Key
        HashSet(std::initializer_list<Key> lst);

        //- Construct as copy
        HashSet(const HashSet<Key, Hash>& hs)
        :
            parent_type(hs)
        {}

        //- Construct by transferring the parameter contents
        HashSet(const Xfer<HashSet<Key, Hash>>& hs)
        :
            parent_type(hs)
        {}

        //- Construct by transferring the parameter contents
        HashSet(const Xfer<HashTable<nil, Key, Hash>>& hs)
        :
            parent_type(hs)
        {}

        //- Construct from the keys of another HashTable,
        //  the type of values held is arbitrary.
        template<class AnyType, class AnyHash>
        explicit HashSet(const HashTable<AnyType, Key, AnyHash>& tbl);


    // Member Functions

      // Edit

        //- Insert a new entry
        //  \return True if the entry inserted, which means that it did
        //  not previously exist in the set.
        bool insert(const Key& key)
        {
            return this->parent_type::insert(key, nil());
        }

        //- Insert keys from the list of Key
        //  \return The number of new elements inserted
        label insert(const UList<Key>& lst);

        //- Insert keys from the list of Key
        //  \return The number of new elements inserted
        template<unsigned Size>
        label insert(const FixedList<Key, Size>& lst);

        //- Insert keys from a initializer list of Key
        //  \return The number of new elements inserted
        label insert(std::initializer_list<Key> lst);

        //- Same as insert (cannot overwrite nil content)
        bool set(const Key& key)
        {
            return insert(key);
        }

        //- Same as insert (cannot overwrite nil content)
        label set(const UList<Key>& lst)
        {
            return insert(lst);
        }

        //- Same as insert (cannot overwrite nil content)
        template<unsigned Size>
        label set(const FixedList<Key, Size>& lst)
        {
            return insert(lst);
        }

        //- Same as insert (cannot overwrite nil content)
        label set(std::initializer_list<Key> lst)
        {
            return insert(lst);
        }

        //- Unset the specified key - same as erase
        //  \return True if the entry existed and was removed
        bool unset(const Key& key)
        {
            return this->parent_type::erase(key);
        }

        //- Unset the listed keys - same as erase
        //  \return The number of items removed
        label unset(const UList<Key>& lst)
        {
            return this->parent_type::erase(lst);
        }

        //- Unset the listed keys - same as erase
        //  \return The number of items removed
        template<unsigned Size>
        label unset(const FixedList<Key, Size>& lst)
        {
            return this->parent_type::erase(lst);
        }

        //- Unset the listed keys - same as erase
        //  \return The number of items removed
        label unset(std::initializer_list<Key> lst)
        {
            return this->parent_type::erase(lst);
        }

        //- Not applicable for HashSet
        template<class UnaryPredicate>
        List<Key> tocValues(const UnaryPredicate&, const bool) = delete;

        //- Not applicable for HashSet
        template<class BinaryPredicate>
        List<Key> tocEntries(const BinaryPredicate&, const bool) = delete;

        //- Not applicable for HashSet
        template<class UnaryPredicate>
        label countValues(const UnaryPredicate&, const bool) = delete;

        //- Not applicable for HashSet
        template<class BinaryPredicate>
        label countEntries(const BinaryPredicate&, const bool) = delete;

        //- Not applicable for HashSet
        template<class UnaryPredicate>
        label filterValues(const UnaryPredicate&, const bool) = delete;

        //- Not applicable for HashSet
        template<class BinaryPredicate>
        label filterEntries(const BinaryPredicate&, const bool) = delete;


    // STL iterators

        iterator begin();
        const_iterator begin() const;
        const_iterator cbegin() const;

        const iterator& end();
        const const_iterator& end() const;
        const const_iterator& cend() const;


    // Writing

        //- Write the unordered keys as a list, with line-breaks if list length
        //  exceeds shortListLen. Using '0' suppresses line-breaks entirely.
        Ostream& writeList(Ostream& os, const label shortListLen=0) const
        {
            return this->writeKeys(os, shortListLen);
        }


    // Member Operators

        //- Return true if the entry exists, same as found()
        inline bool operator()(const Key& key) const;

        //- Return true if the entry exists, same as found().
        inline bool operator[](const Key& key) const;


      // Comparison

        //- Equality. Two hashset are equal when they have the same keys.
        //  Independent of table size or order.
        bool operator==(const this_type& rhs) const;

        //- The opposite of the equality operation.
        bool operator!=(const this_type& rhs) const;


      // Assignment

        //- Assignment from a UList of keys
        void operator=(const UList<Key>& lst);

        //- Assignment from a FixedList of keys
        template<unsigned Size>
        void operator=(const FixedList<Key, Size>& lst);

        //- Assignment from an initializer list of keys
        void operator=(std::initializer_list<Key> lst);


      // Logical operations

        //- Combine entries from HashSets
        void operator|=(const HashSet<Key, Hash>& rhs);

        //- Only retain entries found in both HashSets
        inline void operator&=(const HashSet<Key, Hash>& rhs);

        //- Only retain unique entries (xor)
        void operator^=(const HashSet<Key, Hash>& rhs);

        //- Add entries listed in the given HashSet to this HashSet
        inline void operator+=(const HashSet<Key, Hash>& rhs)
        {
            this->operator|=(rhs);
        }

        //- Remove entries listed in the given HashSet from this HashSet
        inline void operator-=(const HashSet<Key, Hash>& rhs);


    // IOstream Operator

        friend Ostream& operator<< <Key, Hash>
        (
            Ostream& os,
            const HashSet<Key, Hash>& tbl
        );

};


// Global Operators

//- Combine entries from HashSets
template<class Key, class Hash>
HashSet<Key,Hash> operator|
(
    const HashSet<Key,Hash>& hash1,
    const HashSet<Key,Hash>& hash2
);


//- Create a HashSet that only contains entries found in both HashSets
template<class Key, class Hash>
HashSet<Key,Hash> operator&
(
    const HashSet<Key,Hash>& hash1,
    const HashSet<Key,Hash>& hash2
);


//- Create a HashSet that only contains unique entries (xor)
template<class Key, class Hash>
HashSet<Key,Hash> operator^
(
    const HashSet<Key,Hash>& hash1,
    const HashSet<Key,Hash>& hash2
);


//- A HashSet with word keys.
typedef HashSet<> wordHashSet;

//- A HashSet with label keys.
typedef HashSet<label, Hash<label>> labelHashSet;


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

} // End namespace Foam

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

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

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

#endif

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