EFreeList.h

Go to the documentation of this file.

/*
 * $Revision: 2299 $
 *
 * last checkin:
 *   $Author: gutwenger $
 *   $Date: 2012-05-07 15:57:08 +0200 (Mon, 07 May 2012) $
 ***************************************************************/

#ifdef _MSC_VER
#pragma once
#endif

#ifndef OGDF_EFREELIST_H
#define OGDF_EFREELIST_H

#include <ogdf/basic/EList.h>

namespace ogdf {

template<typename E, E* E::*next> class EFreeList;
template<typename E, E* E::*next, int E::*index> class EFreeListIndexPool;

template<typename E, E* E::*next>
class EFreeList
{
public:
    inline EFreeList()  { FreeStack::init(this); }

    ~EFreeList() { this->freeFreeList(); }

    inline E* alloc()
    {
        if (!FreeStack::empty(this))
            return FreeStack::popRet(this);
        else
            return new E();
    }

    inline bool empty() const { return FreeStack::empty(this); }

    inline void free(E* ptr) { FreeStack::push(this, ptr); }

protected:
    inline void freeFreeList()
    {
        while (!FreeStack::empty(this)) { delete FreeStack::popRet(this); };
    }

    E* m_pTop;

    typedef EStack<EFreeList<E, next>, E, &EFreeList<E, next>::m_pTop, next> FreeStack;
};

template<typename E, E* E::*next, int E::*index>
class EFreeListIndexPool
{
public:
    EFreeListIndexPool() : m_nextFreeIndex(0) { }

    inline void free(E* ptr) { m_freeList.free(ptr); }

    inline int numUsedIndices() const { return m_nextFreeIndex; };

    inline E* alloc()
    {
        if (m_freeList.empty())
        {
            E* res = new E();
            res->*index = m_nextFreeIndex++;
            return res;
        } else
        {
            return m_freeList.alloc();
        };
    }

protected:
    int m_nextFreeIndex;

    EFreeList<E, next> m_freeList;
};

} // end of namespace ogdf

#endif /* ELISTPOOL_H_ */