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Merge branch 'np/lookup-object-hashing'
Micro optimize hash function used in the object hash table. * np/lookup-object-hashing: lookup_object: remove hashtable_index() and optimize hash_obj()
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commit
3fb9d685db
22
object.c
22
object.c
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@ -43,16 +43,17 @@ int type_from_string(const char *str)
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die("invalid object type \"%s\"", str);
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}
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static unsigned int hash_obj(struct object *obj, unsigned int n)
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static unsigned int hash_obj(const unsigned char *sha1, unsigned int n)
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{
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unsigned int hash;
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memcpy(&hash, obj->sha1, sizeof(unsigned int));
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return hash % n;
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memcpy(&hash, sha1, sizeof(unsigned int));
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/* Assumes power-of-2 hash sizes in grow_object_hash */
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return hash & (n - 1);
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}
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static void insert_obj_hash(struct object *obj, struct object **hash, unsigned int size)
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{
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unsigned int j = hash_obj(obj, size);
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unsigned int j = hash_obj(obj->sha1, size);
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while (hash[j]) {
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j++;
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@ -62,13 +63,6 @@ static void insert_obj_hash(struct object *obj, struct object **hash, unsigned i
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hash[j] = obj;
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}
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static unsigned int hashtable_index(const unsigned char *sha1)
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{
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unsigned int i;
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memcpy(&i, sha1, sizeof(unsigned int));
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return i % obj_hash_size;
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}
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struct object *lookup_object(const unsigned char *sha1)
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{
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unsigned int i, first;
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@ -77,7 +71,7 @@ struct object *lookup_object(const unsigned char *sha1)
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if (!obj_hash)
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return NULL;
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first = i = hashtable_index(sha1);
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first = i = hash_obj(sha1, obj_hash_size);
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while ((obj = obj_hash[i]) != NULL) {
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if (!hashcmp(sha1, obj->sha1))
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break;
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@ -101,6 +95,10 @@ struct object *lookup_object(const unsigned char *sha1)
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static void grow_object_hash(void)
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{
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int i;
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/*
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* Note that this size must always be power-of-2 to match hash_obj
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* above.
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*/
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int new_hash_size = obj_hash_size < 32 ? 32 : 2 * obj_hash_size;
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struct object **new_hash;
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