dtopen.c

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#include        "dthdr.h"
static char*     Version = "\n@(#)$Id$\0\n";

/*      Make a new dictionary
**
**      Written by Kiem-Phong Vo (5/25/96)
*/

Dt_t* dtopen(Dtdisc_t* disc, Dtmethod_t* meth)
{
        Dt_t*           dt = (Dt_t*)Version;    /* shut-up unuse warning */
        reg int         e;
        Dtdata_t*       data;

        if(!disc || !meth)
                return NIL(Dt_t*);

        /* allocate space for dictionary */
        if(!(dt = (Dt_t*) malloc(sizeof(Dt_t))))
                return NIL(Dt_t*);

        /* initialize all absolutely private data */
        dt->searchf = NIL(Dtsearch_f);
        dt->meth = NIL(Dtmethod_t*);
        dt->disc = NIL(Dtdisc_t*);
        dtdisc(dt,disc,0);
        dt->type = DT_MALLOC;
        dt->nview = 0;
        dt->view = dt->walk = NIL(Dt_t*);
        dt->user = NIL(void*);

        if(disc->eventf)
        {       /* if shared/persistent dictionary, get existing data */
                data = NIL(Dtdata_t*);
                if((e = (*disc->eventf)(dt,DT_OPEN,(void*)(&data),disc)) < 0)
                        goto err_open;
                else if(e > 0)
                {       if(data)
                        {       if(data->type&meth->type)
                                        goto done;
                                else    goto err_open;
                        }

                        if(!disc->memoryf)
                                goto err_open;

                        free((void*)dt);
                        if(!(dt = (*disc->memoryf)(0, 0, sizeof(Dt_t), disc)) )
                                return NIL(Dt_t*);
                        dt->searchf = NIL(Dtsearch_f);
                        dt->meth = NIL(Dtmethod_t*);
                        dt->disc = NIL(Dtdisc_t*);
                        dtdisc(dt,disc,0);
                        dt->type = DT_MEMORYF;
                        dt->nview = 0;
                        dt->view = dt->walk = NIL(Dt_t*);
                }
        }

        /* allocate sharable data */
        if(!(data = (Dtdata_t*)(dt->memoryf)(dt,NIL(void*),sizeof(Dtdata_t),disc)) )
        { err_open:
                free((void*)dt);
                return NIL(Dt_t*);
        }

        data->type = meth->type;
        data->here = NIL(Dtlink_t*);
        data->htab = NIL(Dtlink_t**);
        data->ntab = data->size = data->loop = 0;
        data->minp = 0;

done:
        dt->data = data;
        dt->searchf = meth->searchf;
        dt->meth = meth;

        if(disc->eventf)
                (*disc->eventf)(dt, DT_ENDOPEN, (void*)dt, disc);

        return dt;
}