reftable/stack: expose option to disable auto-compaction
[git.git] / cbtree.h
blob43193abdda23cef279f9e9cee99370509611f7c5
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
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.
14 #ifndef CBTREE_H
15 #define CBTREE_H
17 struct cb_node;
18 struct cb_node {
19 struct cb_node *child[2];
21 * n.b. uint32_t for `byte' is excessive for OIDs,
22 * we may consider shorter variants if nothing else gets stored.
24 uint32_t byte;
25 uint8_t otherbits;
26 uint8_t k[FLEX_ARRAY]; /* arbitrary data, unaligned */
29 struct cb_tree {
30 struct cb_node *root;
33 enum cb_next {
34 CB_CONTINUE = 0,
35 CB_BREAK = 1
38 #define CBTREE_INIT { 0 }
40 static inline void cb_init(struct cb_tree *t)
42 struct cb_tree blank = CBTREE_INIT;
43 memcpy(t, &blank, sizeof(*t));
46 struct cb_node *cb_lookup(struct cb_tree *, const uint8_t *k, size_t klen);
47 struct cb_node *cb_insert(struct cb_tree *, struct cb_node *, size_t klen);
49 typedef enum cb_next (*cb_iter)(struct cb_node *, void *arg);
51 void cb_each(struct cb_tree *, const uint8_t *kpfx, size_t klen,
52 cb_iter, void *arg);
54 #endif /* CBTREE_H */