dtmethod.c

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#include        <cdt/dthdr.h>
#include        <stdlib.h>
 
/*      Change search method.
**
**      Written by Kiem-Phong Vo (05/25/96)
*/
 
Dtmethod_t* dtmethod(Dt_t* dt, Dtmethod_t* meth)
{
        Dtlink_t        *list, *r;
        Dtdisc_t*       disc = dt->disc;
        Dtmethod_t*     oldmeth = dt->meth;
 
        if(!meth || meth->type == oldmeth->type)
                return oldmeth;
 
        /* get the list of elements */
        list = dtflatten(dt);
 
        if (dt->data.type & DT_SET)
        {       if (dt->data.ntab > 0)
                        free(dt->data.htab);
                dt->data.ntab = 0;
                dt->data.htab = NULL;
        }
 
        dt->data.here = NULL;
        dt->data.type = (dt->data.type & ~(DT_METHODS|DT_FLATTEN)) | meth->type;
        dt->meth = meth;
        if(dt->searchf == oldmeth->searchf)
                dt->searchf = meth->searchf;
 
        if(meth->type&(DT_OSET|DT_OBAG))
        {       dt->data.size = 0;
                while(list)
                {       r = list->right;
                        meth->searchf(dt, list, DT_RENEW);
                        list = r;
                }
        }
        else if(oldmeth->type&DT_SET)
        {       int     rehash;
                if((meth->type&DT_SET) && !(oldmeth->type&DT_SET))
                        rehash = 1;
                else    rehash = 0;
 
                dt->data.size = 0;
                dt->data.loop = 0;
                while(list)
                {       r = list->right;
                        if(rehash)
                        {       void* key = _DTOBJ(list,disc->link);
                                key = _DTKEY(key,disc->key,disc->size);
                                list->hash = dtstrhash(key, disc->size);
                        }
                        (void)meth->searchf(dt, list, DT_RENEW);
                        list = r;
                }
        }
 
        return oldmeth;
}