/*
* Look up the record for the given sha1 in the hash map stored in
* obj_hash. Return NULL if it was not found.
*/
struct object *lookup_object(const unsigned char *sha1)
{
unsigned int i, first;
struct object *obj;
if (!obj_hash)
return NULL;
first = i = hash_obj(sha1, obj_hash_size);
while ((obj = obj_hash[i]) != NULL) {
if (!hashcmp(sha1, obj->oid.hash))
break;
i++;
if (i == obj_hash_size)
i = 0;
}
if (obj && i != first) {
/*
* Move object to where we started to look for it so
* that we do not need to walk the hash table the next
* time we look for it.
*/
SWAP(obj_hash[i], obj_hash[first]);
}
return obj;
}
/*
* Insert obj into the hash table hash, which has length size (which
* must be a power of 2). On collisions, simply overflow to the next
* empty bucket.
*/
static void insert_obj_hash(struct object *obj, struct object **hash, unsigned int size)
{
unsigned int j = hash_obj(obj->oid.hash, size);
while (hash[j]) {
j++;
if (j >= size)
j = 0;
}
hash[j] = obj;
}
/* Lookup a decoration pointer */
void *lookup_decoration(struct decoration *n, const struct object *obj)
{
unsigned int j;
/* nothing to lookup */
if (!n->size)
return NULL;
j = hash_obj(obj, n->size);
for (;;) {
struct object_decoration *ref = n->hash + j;
if (ref->base == obj)
return ref->decoration;
if (!ref->base)
return NULL;
if (++j == n->size)
j = 0;
}
}
static void *insert_decoration(struct decoration *n, const struct object *base, void *decoration)
{
int size = n->size;
struct object_decoration *hash = n->hash;
unsigned int j = hash_obj(base, size);
while (hash[j].base) {
if (hash[j].base == base) {
void *old = hash[j].decoration;
hash[j].decoration = decoration;
return old;
}
if (++j >= size)
j = 0;
}
hash[j].base = base;
hash[j].decoration = decoration;
n->nr++;
return NULL;
}
