dllist.hxx

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#ifndef __DLLHHDEFS
#define __DLLHHDEFS

class DllExp DLLItem {
        friend class DLList ;
        DLLItem *next;
        DLLItem *prev;
public:
        DLLItem(){
                next = 0;
                prev = 0;
        };
};

class DllExp DLList {
        DLLItem *head;
        DLLItem *curr;
public:
        DLList (){
                DISABLE_AST
                head = new DLLItem();
                head->next = head;
                head->prev = head;
                curr = head;
                ENABLE_AST
        }
        ~DLList()
        {
                DISABLE_AST
                delete head;
                ENABLE_AST
        }
    void add(DLLItem *item)
        {
                DLLItem *prevp;
                DISABLE_AST
                item->next = head;
                prevp = head->prev;
                item->prev = prevp;
                prevp->next = item;
                head->prev = item;
                ENABLE_AST
        }
        DLLItem *getHead()
        {
                DISABLE_AST
                if(head->next == head)
                {
                        ENABLE_AST
                        return((DLLItem *)0);
                }
                curr = head->next;
                ENABLE_AST
                return( head->next );
        }
        DLLItem *getLast()
        {
                DISABLE_AST
                if(head->prev == head)
                {
                        ENABLE_AST
                        return((DLLItem *)0);
                }
                curr = head->prev;
                ENABLE_AST
                return( head->prev );
        }
        DLLItem *getNext()
        {
                DISABLE_AST
                curr = curr->next;
                if(curr == head)
                {
                        ENABLE_AST
                        return((DLLItem *)0);
                }
                ENABLE_AST
                return( curr );
        }
        DLLItem *removeHead()
        {
                DLLItem *item;
                DISABLE_AST
                item = head->next;
                if(item == head)
                {
                        ENABLE_AST
                        return((DLLItem *)0);
                }
                remove(item);
                ENABLE_AST
                return(item);
        }
        void remove(DLLItem *item)
        {
                DLLItem *prevp, *nextp;
                DISABLE_AST
                prevp = item->prev;
                nextp = item->next;
                prevp->next = item->next;
                nextp->prev = prevp;
                ENABLE_AST
        }
};
#endif