destruction_queue.hpp

Go to the documentation of this file.

// ****************************************************************************
// entity/component/destruction_queue.h
//
// Represents a way to queue component destruction in order to 
// reduce creation complexity from O(m*nlog(n)) to O(m+n)
// 
// Copyright Chris Glover 2014-2015
//
// Distributed under the Boost Software License, Version 1.0.
// See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt
//
// ****************************************************************************
#ifndef _ENTITY_COMPONENT_DESTRUCTIONQUEUE_H_INCLUDED_
#define _ENTITY_COMPONENT_DESTRUCTIONQUEUE_H_INCLUDED_

#include <algorithm>
#include <functional>
#include <vector>

#include "entity/config.hpp" // IWYU pragma: keep
#include "entity/entity.hpp"

// ----------------------------------------------------------------------------
//
namespace entity { namespace component 
{
    template<typename ComponentPool>
    class destruction_queue
    {
    public:

        typedef typename ComponentPool::type type;

        destruction_queue(ComponentPool& p)
            : pool_(p)
        {}

        ~destruction_queue()
        {
            flush();
        }

        void push(weak_entity e)
        {
            destroyed_.push_back(e);
        }

        void flush()
        {
            std::sort(destroyed_.begin(), destroyed_.end(), std::greater<weak_entity>());
            pool_.destroy_range(destroyed_.begin(), destroyed_.end());
            clear();
        }

        void clear()
        {
            destroyed_.clear();
        }

    private: 

        // No copying.
        destruction_queue(destruction_queue const&);
        destruction_queue operator=(destruction_queue);

        std::vector<weak_entity> destroyed_;
        ComponentPool& pool_;
    };
} } // namespace entity { namespace component {

#endif // _ENTITY_COMPONENT_DESTRUCTIONQUEUE_H_INCLUDED_