dtflatten.c

Go to the documentation of this file.

#include        "dthdr.h"

/*      Flatten a dictionary into a linked list.
**      This may be used when many traversals are likely.
**
**      Written by Kiem-Phong Vo (5/25/96).
*/

Dtlink_t* dtflatten(Dt_t* dt)
{
        reg Dtlink_t    *t, *r, *list, *last, **s, **ends;

        /* already flattened */
        if(dt->data->type&DT_FLATTEN )
                return dt->data->here;

        list = last = NIL(Dtlink_t*);
        if(dt->data->type&(DT_SET|DT_BAG))
        {       for(ends = (s = dt->data->htab) + dt->data->ntab; s < ends; ++s)
                {       if((t = *s) )
                        {       if(last)
                                        last->right = t;
                                else    list = last = t;
                                while(last->right)
                                        last = last->right;
                                *s = last;
                        }
                }
        }
        else if(dt->data->type&(DT_LIST|DT_STACK|DT_QUEUE) )
                list = dt->data->head;
        else if((r = dt->data->here) ) /*if(dt->data->type&(DT_OSET|DT_OBAG))*/
        {       while((t = r->left) )
                        RROTATE(r,t);
                for(list = last = r, r = r->right; r; last = r, r = r->right)
                {       if((t = r->left) )
                        {       do      RROTATE(r,t);
                                while((t = r->left) );

                                last->right = r;
                        }
                }
        }

        dt->data->here = list;
        dt->data->type |= DT_FLATTEN;

        return list;
}