/*
 * Pool.hpp
 *
 *  Created on: 12 δεκ. 2019 γ.
 *      Author: LeonidTitov
 */

#ifndef LIB_COMMON_POOL_HPP_
#define LIB_COMMON_POOL_HPP_

#include <cstddef>
#include <bitset>

namespace common {

template<typename Item>
struct PoolInterface {
    virtual Item * get() = 0;
    virtual void free( Item * & ) = 0;
    virtual ~PoolInterface() = default;
};

template<typename Item, std::size_t quantity>
struct Pool : public PoolInterface<Item> {

    static const std::size_t size = quantity;
    typedef Item ItemType;

    Item * get();
    void free( Item * & );

    virtual ~Pool() noexcept {}
private:
    Item pool[size];
    typedef std::bitset<size> Infos;
    Infos info;
};

}

template<typename Item, std::size_t quantity>
inline Item * common::Pool<Item, quantity>::get() {

    for( std::size_t index = 0; index < size; ++index )
        if( not info.test(index) ) {
            info.set(index);
            return &pool[index];
        }

    return nullptr;
}

template<typename Item, std::size_t quantity>
inline void common::Pool<Item, quantity>::free( Item * & item ) {

     std::size_t index = item - pool;

     if( info.test(index) ) {
         item = nullptr;
         info.reset(index);
     }

}

#endif /* LIB_COMMON_POOL_HPP_ */