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1/*
2 * crit-bit tree implementation, does no allocations internally
3 * For more information on crit-bit trees: https://cr.yp.to/critbit.html
4 * Based on Adam Langley's adaptation of Dan Bernstein's public domain code
5 * git clone https://github.com/agl/critbit.git
6 *
7 * This is adapted to store arbitrary data (not just NUL-terminated C strings
8 * and allocates no memory internally. The user needs to allocate
9 * "struct cb_node" and fill cb_node.k[] with arbitrary match data
10 * for memcmp.
11 * If "klen" is variable, then it should be embedded into "c_node.k[]"
12 * Recursion is bound by the maximum value of "klen" used.
13 */
14#ifndef CBTREE_H
15#define CBTREE_H
16
17struct cb_node;
18struct cb_node {
19 struct cb_node *child[2];
20 /*
21 * n.b. uint32_t for `byte' is excessive for OIDs,
22 * we may consider shorter variants if nothing else gets stored.
23 */
24 uint32_t byte;
25 uint8_t otherbits;
26 uint8_t k[FLEX_ARRAY]; /* arbitrary data, unaligned */
27};
28
29struct cb_tree {
30 struct cb_node *root;
31};
32
33enum cb_next {
34 CB_CONTINUE = 0,
35 CB_BREAK = 1
36};
37
38#define CBTREE_INIT { 0 }
39
40static inline void cb_init(struct cb_tree *t)
41{
42 struct cb_tree blank = CBTREE_INIT;
43 memcpy(t, &blank, sizeof(*t));
44}
45
46struct cb_node *cb_lookup(struct cb_tree *, const uint8_t *k, size_t klen);
47struct cb_node *cb_insert(struct cb_tree *, struct cb_node *, size_t klen);
48
49typedef enum cb_next (*cb_iter)(struct cb_node *, void *arg);
50
51void cb_each(struct cb_tree *, const uint8_t *kpfx, size_t klen,
52 cb_iter, void *arg);
53
54#endif /* CBTREE_H */