SG_DList.h

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/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * This program 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 2
 * of the License, or (at your option) any later version.
 *
 * This program 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 this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
 * All rights reserved.
 *
 * The Original Code is: all of this file.
 *
 * Contributor(s): none yet.
 *
 * ***** END GPL LICENSE BLOCK *****
 */

#ifndef __SG_DLIST
#define __SG_DLIST

#include <stdlib.h>

#ifdef WITH_CXX_GUARDEDALLOC
#include "MEM_guardedalloc.h"
#endif

class SG_DList
{
protected :
    SG_DList* m_flink;
    SG_DList* m_blink;

public:
    template<typename T> class iterator
    {
    private:
        SG_DList&   m_head;
        T*          m_current;
    public:
        typedef iterator<T> _myT;
        iterator(SG_DList& head) : m_head(head), m_current(NULL) {}
        ~iterator() {}

        void begin()
        {
            m_current = (T*)m_head.Peek();
        }
        void back()
        {
            m_current = (T*)m_head.Back();
        }
        bool end()
        {
            return (m_current == (T*)m_head.Self());
        }
        bool add_back(T* item)
        {
            return m_current->AddBack(item);
        }
        T* operator*()
        {
            return m_current;
        }
        _myT& operator++()
        {
            // no check of NULL! make sure you don't try to increment beyond end
            m_current = (T*)m_current->Peek();
            return *this;
        }
        _myT& operator--()
        {
            // no check of NULL! make sure you don't try to increment beyond end
            m_current = (T*)m_current->Back();
            return *this;
        }
    };

    template<typename T> class const_iterator
    {
    private:
        const SG_DList& m_head;
        const T*        m_current;
    public:
        typedef const_iterator<T> _myT;
        const_iterator(const SG_DList& head) : m_head(head), m_current(NULL) {}
        ~const_iterator() {}

        void begin()
        {
            m_current = (const T*)m_head.Peek();
        }
        void back()
        {
            m_current = (const T*)m_head.Back();
        }
        bool end()
        {
            return (m_current == (const T*)m_head.Self());
        }
        const T* operator*()
        {
            return m_current;
        }
        _myT& operator++()
        {
            // no check of NULL! make sure you don't try to increment beyond end
            m_current = (const T*)m_current->Peek();
            return *this;
        }
        _myT& operator--()
        {
            // no check of NULL! make sure you don't try to increment beyond end
            m_current = (const T*)m_current->Back();
            return *this;
        }
    };

    SG_DList()
    {
        m_flink = m_blink = this;
    }
    SG_DList(const SG_DList& other)
    {
        m_flink = m_blink = this;
    }
    virtual ~SG_DList()
    {
        Delink();
    }

    inline bool Empty()               // Check for empty queue
    {
        return ( m_flink == this );
    }
    bool AddBack( SG_DList *item )  // Add to the back
    {
        if (!item->Empty())
            return false;
        item->m_blink = m_blink;
        item->m_flink = this;
        m_blink->m_flink = item;
        m_blink = item;
        return true;
    }
    bool AddFront( SG_DList *item )  // Add to the back
    {
        if (!item->Empty())
            return false;
        item->m_flink = m_flink;
        item->m_blink = this;
        m_flink->m_blink = item;
        m_flink = item;
        return true;
    }
    SG_DList *Remove()           // Remove from the front
    {
        if (Empty())
        {
            return NULL;
        }
        SG_DList* item = m_flink;
        m_flink = item->m_flink;
        m_flink->m_blink = this;
        item->m_flink = item->m_blink = item;
        return item;
    }
    bool Delink()             // Remove from the middle
    {
        if (Empty())
            return false;
        m_blink->m_flink = m_flink;
        m_flink->m_blink = m_blink;
        m_flink = m_blink = this;
        return true;
    }
    inline SG_DList *Peek()         // Look at front without removing
    {
        return m_flink;
    }
    inline SG_DList *Back()         // Look at front without removing
    {
        return m_blink;
    }
    inline SG_DList *Self()
    {
        return this;
    }
    inline const SG_DList *Peek() const         // Look at front without removing
    {
        return (const SG_DList*)m_flink;
    }
    inline const SG_DList *Back() const         // Look at front without removing
    {
        return (const SG_DList*)m_blink;
    }
    inline const SG_DList *Self() const
    {
        return this;
    }
    
    
#ifdef WITH_CXX_GUARDEDALLOC
public:
    void *operator new(size_t num_bytes) { return MEM_mallocN(num_bytes, "GE:SG_DList"); }
    void operator delete( void *mem ) { MEM_freeN(mem); }
#endif
};

template<typename T> class SG_DListHead : public SG_DList
{
public:
    typedef SG_DListHead<T> _myT;
    SG_DListHead() : SG_DList() {}
    SG_DListHead(const _myT& other) : SG_DList()
    {
        // copy the list, assuming objects of type T
        const_iterator<T> eit(other);
        T* elem;
        for (eit.begin(); !eit.end(); ++eit) {
            elem = (*eit)->GetReplica();
            AddBack(elem);
        }
    }
    virtual ~SG_DListHead() {}
    T* Remove()
    {
        return static_cast<T*>(SG_DList::Remove());
    }

};

#endif //__SG_DLIST