SG_QList.h

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/*
 * $Id: SG_QList.h 35082 2011-02-22 19:30:37Z jesterking $
 *
 * ***** 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