[thirdparty/git.git] / cbtree.h

/*
 * 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

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 */
Commit	Line	Data
92d8ed8a EW	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
92d8ed8a EW	17	struct cb_node;
	18	struct 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;
8bcda98d	26	uint8_t k[FLEX_ARRAY]; /* arbitrary data, unaligned */
92d8ed8a EW	27	};
	28
	29	struct cb_tree {
	30	struct cb_node *root;
	31	};
	32
	33	enum cb_next {
	34	CB_CONTINUE = 0,
	35	CB_BREAK = 1
	36	};
	37
538835d2	38	#define CBTREE_INIT { 0 }
92d8ed8a EW	39
	40	static inline void cb_init(struct cb_tree *t)
	41	{
538835d2 ÆAB	42	struct cb_tree blank = CBTREE_INIT;
538835d2 ÆAB	43	memcpy(t, &blank, sizeof(*t));
92d8ed8a EW	44	}
	45
	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);
92d8ed8a EW	48
	49	typedef enum cb_next (cb_iter)(struct cb_node , void *arg);
	50
	51	void cb_each(struct cb_tree , const uint8_t kpfx, size_t klen,
	52	cb_iter, void *arg);
	53
	54	#endif /* CBTREE_H */