git

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/*
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 * A wrapper around cbtree which stores oids
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 * May be used to replace oid-array for prefix (abbreviation) matches
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 */
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#include "git-compat-util.h"
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#include "oidtree.h"
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#include "hash.h"
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struct oidtree_iter_data {
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	oidtree_iter fn;
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	void *arg;
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	size_t *last_nibble_at;
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	int algo;
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	uint8_t last_byte;
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};
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void oidtree_init(struct oidtree *ot)
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{
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	cb_init(&ot->tree);
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	mem_pool_init(&ot->mem_pool, 0);
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}
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void oidtree_clear(struct oidtree *ot)
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{
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	if (ot) {
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		mem_pool_discard(&ot->mem_pool, 0);
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		oidtree_init(ot);
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	}
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}
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void oidtree_insert(struct oidtree *ot, const struct object_id *oid)
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{
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	struct cb_node *on;
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	struct object_id k;
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	if (!oid->algo)
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		BUG("oidtree_insert requires oid->algo");
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	on = mem_pool_alloc(&ot->mem_pool, sizeof(*on) + sizeof(*oid));
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	/*
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	 * Clear the padding and copy the result in separate steps to
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	 * respect the 4-byte alignment needed by struct object_id.
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	 */
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	oidcpy(&k, oid);
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	memcpy(on->k, &k, sizeof(k));
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	/*
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	 * n.b. Current callers won't get us duplicates, here.  If a
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	 * future caller causes duplicates, there'll be a a small leak
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	 * that won't be freed until oidtree_clear.  Currently it's not
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	 * worth maintaining a free list
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	 */
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	cb_insert(&ot->tree, on, sizeof(*oid));
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}
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int oidtree_contains(struct oidtree *ot, const struct object_id *oid)
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{
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	struct object_id k;
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	size_t klen = sizeof(k);
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	oidcpy(&k, oid);
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	if (oid->algo == GIT_HASH_UNKNOWN)
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		klen -= sizeof(oid->algo);
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	/* cb_lookup relies on memcmp on the struct, so order matters: */
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	klen += BUILD_ASSERT_OR_ZERO(offsetof(struct object_id, hash) <
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				offsetof(struct object_id, algo));
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	return cb_lookup(&ot->tree, (const uint8_t *)&k, klen) ? 1 : 0;
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}
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static enum cb_next iter(struct cb_node *n, void *arg)
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{
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	struct oidtree_iter_data *x = arg;
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	struct object_id k;
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	/* Copy to provide 4-byte alignment needed by struct object_id. */
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	memcpy(&k, n->k, sizeof(k));
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	if (x->algo != GIT_HASH_UNKNOWN && x->algo != k.algo)
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		return CB_CONTINUE;
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	if (x->last_nibble_at) {
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		if ((k.hash[*x->last_nibble_at] ^ x->last_byte) & 0xf0)
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			return CB_CONTINUE;
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	}
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	return x->fn(&k, x->arg);
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}
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void oidtree_each(struct oidtree *ot, const struct object_id *oid,
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			size_t oidhexsz, oidtree_iter fn, void *arg)
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{
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	size_t klen = oidhexsz / 2;
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	struct oidtree_iter_data x = { 0 };
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	assert(oidhexsz <= GIT_MAX_HEXSZ);
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	x.fn = fn;
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	x.arg = arg;
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	x.algo = oid->algo;
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	if (oidhexsz & 1) {
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		x.last_byte = oid->hash[klen];
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		x.last_nibble_at = &klen;
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	}
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	cb_each(&ot->tree, (const uint8_t *)oid, klen, iter, &x);
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}
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