5 static inline int height(struct node *n) { return n ? n->h : 0; }
7 static int rot(void **p, struct node *x, int dir /* deeper side */)
9 struct node *y = x->a[dir];
10 struct node *z = y->a[!dir];
13 if (hz > height(y->a[dir])) {
23 x->a[dir] = z->a[!dir];
24 y->a[!dir] = z->a[dir];
48 /* balance *p, return 0 if height is unchanged. */
49 int __tsearch_balance(void **p)
52 int h0 = height(n->a[0]);
53 int h1 = height(n->a[1]);
54 if (h0 - h1 + 1u < 3u) {
56 n->h = h0<h1 ? h1+1 : h0+1;
59 return rot(p, n, h0<h1);
62 void *tsearch(const void *key, void **rootp,
63 int (*cmp)(const void *, const void *))
69 struct node *n = *rootp;
76 int c = cmp(key, n->key);
82 r = malloc(sizeof *r);
86 r->a[0] = r->a[1] = 0;
88 /* insert new node, rebalance ancestors. */
90 while (i && __tsearch_balance(a[--i]));