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/*
* crit-bit tree implementation, does no allocations internally
* For more information on crit-bit trees: https://cr.yp.to/critbit.html
* Based on Adam Langley's adaptation of Dan Bernstein's public domain code
* git clone https://github.com/agl/critbit.git
*
* This is adapted to store arbitrary data (not just NUL-terminated C strings
* and allocates no memory internally. The user needs to allocate
* "struct cb_node" and fill cb_node.k[] with arbitrary match data
* for memcmp.
* If "klen" is variable, then it should be embedded into "c_node.k[]"
* Recursion is bound by the maximum value of "klen" used.
*/
#ifndef CBTREE_H
#define CBTREE_H
#include "git-compat-util.h"
struct cb_node;
struct cb_node {
struct cb_node *child[2];
/*
* n.b. uint32_t for `byte' is excessive for OIDs,
* we may consider shorter variants if nothing else gets stored.
*/
uint32_t byte;
uint8_t otherbits;
uint8_t k[FLEX_ARRAY]; /* arbitrary data, unaligned */
};
struct cb_tree {
struct cb_node *root;
};
enum cb_next {
CB_CONTINUE = 0,
CB_BREAK = 1
};
#define CBTREE_INIT { 0 }
static inline void cb_init(struct cb_tree *t)
{
struct cb_tree blank = CBTREE_INIT;
memcpy(t, &blank, sizeof(*t));
}
struct cb_node *cb_lookup(struct cb_tree *, const uint8_t *k, size_t klen);
struct cb_node *cb_insert(struct cb_tree *, struct cb_node *, size_t klen);
typedef enum cb_next (*cb_iter)(struct cb_node *, void *arg);
void cb_each(struct cb_tree *, const uint8_t *kpfx, size_t klen,
cb_iter, void *arg);
#endif /* CBTREE_H */
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