#include "llist.h"
#include <stdlib.h>

/* create new linked list
 * use llistFree after use
 * retturns NULL on failure
 */
llist *llistNew(void *data, int (*cmpFN)(void *a, void *b)) {
  llist *r = (llist *)malloc(sizeof(llist));
  if (r != NULL) {
    r->cmpFn = cmpFN;
    r->data = data;
    r->prev = NULL;
    r->next = NULL;
  }
  return r;
}

/*return  last node of linked list;
 */
llist *llistTail(llist *l) {
  llist *tail = l;
  while (tail->next != NULL) {
    tail = tail->next;
  }
  return tail;
}

/* creates new node from data and appends it to tail
 *
 */
llist *llistAppend(llist *head, void *data) {
  llist *new = llistNew(data, head->cmpFn);
  if (new != NULL) {
    llist *tail = llistTail(head);
    new->data = data;
    new->next = NULL;
    new->prev = tail;
    tail->next = new;
  }
  return new;
}

/*
 * return Node containing key or NULL
 */
llist *llistGet(llist *head, void *key) {
  llist *c = head;
  while (c != NULL) {
    if (head->cmpFn(c->data, key) == 0) {
      return c;
    }
    c = c->next;
  }
  return NULL;
}

bool llistContains(llist *head, void *key) {
  return llistGet(head, key) != NULL;
}
void llistFree(llist *head) {
  while (head != NULL) {
    llist *tmp = head->next;
    free(head);
    head = tmp;
  }
}