NVList.h

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#ifndef _NVList_h_
#define _NVList_h_

#include"NVlist.h"

/* NVContainer Class Library */
class NVList;
class NVListIter;

class NVList:public NVlist {
        friend class NVListIter;

      public:
         NVList():NVlist() {
        } NVList(const char *dbname, int flags = 0):NVlist(dbname, flags) {
        }

        int is_empty(void);
        void prepend(const char *data, size_t szdata);
        void append(const char *data, size_t szdata);
        void remove(void);
        void clear(void);

        void print(std::ostream & os);
};

class NVListIter {
        NVList *l;
         NVList::Record * pos;
         NVList::Record * tail;
      public:
         NVListIter() {
                l = NULL;
                pos = NULL;
        } NVListIter(NVList & nvl) {
                l = &nvl;
                l->lock(NVList::ShrdLock);
                pos = NULL;
        }
        ~NVListIter() {
                detach();
        }

        void attach(NVList & nvl) {
                detach();
                l = &nvl;
                l->lock(NVList::ShrdLock);
                pos = NULL;
                tail = l->o2r(l->getdata());
        }
        void detach() {
                if (l) {
                        l->lock(NVList::UnLock);
                }
                l = NULL;
        }

        void first() {
                if (l)
                        pos = l->o2r(tail->next);
        }
        int valid() {
                return pos != NULL;
        }
        void next() {
                if (pos) {
                        if (pos == tail)
                                pos = 0;
                        else
                                pos = l->o2r(pos->next);
                }
        }

        void data(const char **data, unsigned int *szdata) {
                (*data) = l->mem_p + l->r2o(pos) + sizeof(NVList::Record);
                (*szdata) = pos->szdata;
        }
};

#endif

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