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From: Junio C Hamano <gitster@pobox.com>
To: git@vger.kernel.org
Subject: [PATCH 02/11] object.c: remove duplicated code for object hashing
Date: Thu, 11 Aug 2011 10:53:07 -0700	[thread overview]
Message-ID: <1313085196-13249-3-git-send-email-gitster@pobox.com> (raw)
In-Reply-To: <1313085196-13249-1-git-send-email-gitster@pobox.com>

The index into object hash was computed in two different places,
risking them to diverge. Implement a single helper function and
use it in these two locations.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 object.c |   17 +++++------------
 1 files changed, 5 insertions(+), 12 deletions(-)

diff --git a/object.c b/object.c
index 35ff130..4ff2d7d 100644
--- a/object.c
+++ b/object.c
@@ -43,23 +43,16 @@ struct object *get_indexed_object(unsigned int idx)
 	return obj_hash[idx];
 }
 
-static unsigned int hash_obj(struct object *obj, unsigned int n)
+static unsigned int hash_val(const unsigned char *sha1)
 {
 	unsigned int hash;
-	memcpy(&hash, obj->sha1, sizeof(unsigned int));
-	return hash % n;
-}
-
-static unsigned int hashtable_index(const unsigned char *sha1)
-{
-	unsigned int i;
-	memcpy(&i, sha1, sizeof(unsigned int));
-	return i % obj_hash_size;
+	memcpy(&hash, sha1, sizeof(unsigned int));
+	return hash;
 }
 
 static void insert_obj_hash(struct object *obj, struct object **hash, unsigned int size)
 {
-	unsigned int j = hash_obj(obj, size);
+	unsigned int j = hash_val(obj->sha1) % size;
 
 	while (hash[j]) {
 		j++;
@@ -77,7 +70,7 @@ struct object *lookup_object(const unsigned char *sha1)
 	if (!obj_hash)
 		return NULL;
 
-	i = hashtable_index(sha1);
+	i = hash_val(sha1) % obj_hash_size;
 	while ((obj = obj_hash[i]) != NULL) {
 		if (!hashcmp(sha1, obj->sha1))
 			break;
-- 
1.7.6.433.g1421f

  parent reply	other threads:[~2011-08-11 17:53 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-08-11 17:53 [PATCH 00/11] Micro-optimizing lookup_object() Junio C Hamano
2011-08-11 17:53 ` [PATCH 01/11] object.c: code movement for readability Junio C Hamano
2011-08-11 17:53 ` Junio C Hamano [this message]
2011-08-11 17:53 ` [PATCH 03/11] pack-objects --count-only Junio C Hamano
2011-08-11 17:53 ` [PATCH 04/11] object: next_size() helper for readability Junio C Hamano
2011-08-11 17:53 ` [PATCH 05/11] object hash: we know the table size is a power of two Junio C Hamano
2011-08-11 17:53 ` [PATCH 06/11] object: growing the hash-table more aggressively does not help much Junio C Hamano
2011-08-11 17:53 ` [PATCH 07/11] object: try naive cuckoo hashing Junio C Hamano
2011-08-11 17:53 ` [PATCH 08/11] object: try 5-way cuckoo -- use all 20-bytes of SHA-1 Junio C Hamano
2011-08-11 17:53 ` [PATCH 09/11] object: try 4-way cuckoo Junio C Hamano
2011-08-11 17:53 ` [PATCH 10/11] object: try 3-way cuckoo Junio C Hamano
2011-08-11 17:53 ` [PATCH 11/11] object: try 2-way cuckoo again Junio C Hamano
2011-08-11 23:33 ` [FFT/PATCH 12/11] object.c: make object hash implementation more opaque Junio C Hamano
2011-08-12 15:59 ` git_checkattr() is inefficient when repeated [Re: [PATCH 00/11] Micro-optimizing lookup_object()] Thomas Rast
2011-08-15 23:19   ` Junio C Hamano

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