dtdisc.c

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#include        "dthdr.h"

/*      Change discipline.
**      dt :    dictionary
**      disc :  discipline
**
**      Written by Kiem-Phong Vo (5/26/96)
*/

static void* dtmemory(Dt_t* dt,void* addr,size_t size,Dtdisc_t* disc)
{
        if(addr)
        {       if(size == 0)
                {       free(addr);
                        return NIL(void*);
                }
                else    return realloc(addr,size);
        }
        else    return size > 0 ? malloc(size) : NIL(void*);
}

Dtdisc_t* dtdisc(Dt_t* dt, Dtdisc_t* disc, int type)
{
        reg Dtsearch_f  searchf;
        reg Dtlink_t    *r, *t;
        reg char*       k;
        reg Dtdisc_t*   old;

        if(!(old = dt->disc) )  /* initialization call from dtopen() */
        {       dt->disc = disc;
                if(!(dt->memoryf = disc->memoryf) )
                        dt->memoryf = dtmemory;
                return disc;
        }

        if(!disc)       /* only want to know current discipline */
                return old;

        searchf = dt->meth->searchf;

        UNFLATTEN(dt);

        if(old->eventf && (*old->eventf)(dt,DT_DISC,(void*)disc,old) < 0)
                return NIL(Dtdisc_t*);

        dt->disc = disc;
        if(!(dt->memoryf = disc->memoryf) )
                dt->memoryf = dtmemory;

        if(dt->data->type&(DT_STACK|DT_QUEUE|DT_LIST))
                goto done;
        else if(dt->data->type&DT_BAG)
        {       if(type&DT_SAMEHASH)
                        goto done;
                else    goto dt_renew;
        }
        else if(dt->data->type&(DT_SET|DT_BAG))
        {       if((type&DT_SAMEHASH) && (type&DT_SAMECMP))
                        goto done;
                else    goto dt_renew;
        }
        else /*if(dt->data->type&(DT_OSET|DT_OBAG))*/
        {       if(type&DT_SAMECMP)
                        goto done;
        dt_renew:
                r = dtflatten(dt);
                dt->data->type &= ~DT_FLATTEN;
                dt->data->here = NIL(Dtlink_t*);
                dt->data->size = 0;

                if(dt->data->type&(DT_SET|DT_BAG))
                {       reg Dtlink_t    **s, **ends;
                        ends = (s = dt->data->htab) + dt->data->ntab;
                        while(s < ends)
                                *s++ = NIL(Dtlink_t*);
                }

                /* reinsert them */
                while(r)
                {       t = r->right;
                        if(!(type&DT_SAMEHASH)) /* new hash value */
                        {       k = (char*)_DTOBJ(r,disc->link);
                                k = _DTKEY((void*)k,disc->key,disc->size);
                                r->hash = _DTHSH(dt,k,disc,disc->size);
                        }
                        (void)(*searchf)(dt,(void*)r,DT_RENEW);
                        r = t;
                }
        }

done:
        return old;
}