source: trunk/nv/stl/hash_store.hh @ 530

// Copyright (C) 2015-2017 ChaosForge Ltd
// http://chaosforge.org/
//
// This file is part of Nova libraries. 
// For conditions of distribution and use, see copying.txt file in root folder.

/**
 * @file hash_store.hh
 * @author Kornel Kisielewicz
 * @brief hash_store class
 */

#ifndef NV_STL_HASH_STORE_HH
#define NV_STL_HASH_STORE_HH

#include <nv/common.hh>
#include <nv/stl/container/hash_table.hh>
#include <nv/stl/container/hash_table_policy.hh>

namespace nv
{

        template <
                typename Mapped,
                typename Hash
        >
        struct hash_store_entry_policy
        {
                typedef Hash    key_type;
                typedef Hash    query_type;
                typedef Mapped  mapped_type;
                typedef Hash    hash_type;
                typedef pair< hash_type, mapped_type > value_type;

                struct entry_type
                {
                        value_type value;
                };

                static constexpr hash_type get_hash( const key_type& t ) { return t; }
                static constexpr hash_type get_hash( const value_type& t ) { return t.first; }
                static constexpr hash_type get_entry_hash( const entry_type* entry ) { return entry->value.first; }
                static constexpr hash_type get_value_hash( const value_type& value ) { return value.first; }

                static constexpr bool entry_compare( const entry_type* entry, hash_type h, const key_type& )
                {
                        return entry->value.first == h;
                }
                static constexpr bool entry_compare( const entry_type* entry, hash_type h, const value_type& )
                {
                        return entry->value.first == h;
                }

                template < typename... Args >
                static void entry_construct( entry_type* entry, hash_type hash_code, Args&&... params )
                {
                        construct_object( &( entry->value ), ::nv::forward<Args>( params )... );
                        entry->value.first = hash_code;
                }

                static void entry_destroy( entry_type* entry )
                {
                        destroy_object( &( entry->value ) );
                }

        };

        template < typename H, typename T >
        class hash_store 
                : public hash_table_base< 
                        hash_store_entry_policy< T, H >
                >                       
        {
        public:
                typedef hash_table_base< hash_store_entry_policy< T, H > > base_type;
                typedef typename base_type::iterator           iterator;
                typedef typename base_type::const_iterator     const_iterator;
                typedef typename base_type::insert_return_type insert_return_type;
                typedef H key_type;
                typedef H query_type;
                typedef T mapped_type;
                typedef H hash_type;

                using base_type::base_type;

                mapped_type& operator[]( const key_type& key )
                {
                        return ( *base_type::insert_key( key ).first ).second;
                }

                mapped_type& at( const query_type& key )
                {
                        iterator it = base_type::find( key );
                        NV_ASSERT_ALWAYS( it != base_type::end(), "Key not found in map!" );
                        return it->second;
                }

                const mapped_type& at( const query_type& key ) const
                {
                        const_iterator it = base_type::find( key );
                        NV_ASSERT_ALWAYS( it != base_type::cend(), "Key not found in map!" );
                        return it->second;
                }

                template < typename M >
                insert_return_type assign( hash_type& k, M&& obj )
                {
                        insert_return_type result = base_type::try_insert( k, nv::forward<M>( obj ) );
                        if ( !result.second ) result.first->second = nv::move(obj);
                        return result;
                }

        };

}

#endif // NV_STL_HASH_STORE_HH