SG_QList.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_QLIST
#define __SG_QLIST

#include "SG_DList.h"

class SG_QList : public SG_DList
{
protected :
    SG_QList* m_fqlink;
    SG_QList* m_bqlink;

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

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

    SG_QList() : SG_DList()
    {
        m_fqlink = m_bqlink = this;
    }
    SG_QList(const SG_QList& other) : SG_DList()
    {
        m_fqlink = m_bqlink = this;
    }
    virtual ~SG_QList()
    {
        QDelink();
    }

    inline bool QEmpty()               // Check for empty queue
    {
        return ( m_fqlink == this );
    }
    bool QAddBack( SG_QList *item )  // Add to the back
    {
        if (!item->QEmpty())
            return false;
        item->m_bqlink = m_bqlink;
        item->m_fqlink = this;
        m_bqlink->m_fqlink = item;
        m_bqlink = item;
        return true;
    }
    bool QAddFront( SG_QList *item )  // Add to the back
    {
        if (!item->Empty())
            return false;
        item->m_fqlink = m_fqlink;
        item->m_bqlink = this;
        m_fqlink->m_bqlink = item;
        m_fqlink = item;
        return true;
    }
    SG_QList *QRemove()           // Remove from the front
    {
        if (QEmpty())
        {
            return NULL;
        }
        SG_QList* item = m_fqlink;
        m_fqlink = item->m_fqlink;
        m_fqlink->m_bqlink = this;
        item->m_fqlink = item->m_bqlink = item;
        return item;
    }
    bool QDelink()             // Remove from the middle
    {
        if (QEmpty())
            return false;
        m_bqlink->m_fqlink = m_fqlink;
        m_fqlink->m_bqlink = m_bqlink;
        m_fqlink = m_bqlink = this;
        return true;
    }
    inline SG_QList *QPeek()            // Look at front without removing
    {
        return m_fqlink;
    }
    inline SG_QList *QBack()            // Look at front without removing
    {
        return m_bqlink;
    }


#ifdef WITH_CXX_GUARDEDALLOC
public:
    void *operator new(size_t num_bytes) { return MEM_mallocN(num_bytes, "GE:SG_QList"); }
    void operator delete( void *mem ) { MEM_freeN(mem); }
#endif
};

#endif //__SG_QLIST