int findRec(dbkeytype key, dbdatatype *data, indextype *idx)
{
  Dbrec rec=db,prior=NULL;
  int cmp;
  
  if(rec)
    do {
      if((cmp=comparedbkey(key,rec->key))<=0)
	break;
      prior = rec;
      rec = rec->next;
    } while(rec!=db);
  idx->it = rec;
  idx->prior = prior;
  if(rec&&cmp==0) {
    copydbdata(rec->data,*data);
    return 1;
  }
  return 0;
}

int createRec(dbkeytype key, dbdatatype data, indextype idx)
/* Precondition: idx->prior points to the record after which the new
                 record should be inserted. (If NULL, the new record
                 is inserted at the head of the list. idx->it points
                 to the record after idx->prior.
   Action: If the database is not full, adds the record with key key and
           data data, and returns 1. Otherwise, returns 0. */
{
  Dbrec rec;

  rec=(Dbrec)malloc(sizeof(struct dbrec));
  if(rec==NULL)
    return 0;
  copydbkey(key,rec->key);
  copydbdata(data,rec->data);
  if(db==idx.it) /* Note: this is true if db == NULL. */
    db = rec;
  if(idx.prior) {
    idx.prior->next = rec;
    rec->next=idx.it;
    }
  else
    rec->next = rec;
  return 1;
}

void eachElement(Listptr ptr, void (*fn)(ListData))
{
  Listptr p=ptr;

  if(p)
    do {
      (*fn)(p->data);
      p = p->next;
    }
    while(p!=ptr);
}