From: Eric Blake <ebb9@byu.net>
Date: Thu, 18 Jun 2009 19:18:34 +0000 (-0600)
Subject: hash: avoid no-op rehashing
X-Git-Tag: v0.1~5849
X-Git-Url: http://erislabs.org.uk/gitweb/?a=commitdiff_plain;h=86514ea5ebf71c35726c21ae077f2a3a10e196e2;p=gnulib.git

hash: avoid no-op rehashing

* lib/hash.c (hash_rehash): Recognize useless rehash attempts.

Signed-off-by: Eric Blake <ebb9@byu.net>
---

diff --git a/ChangeLog b/ChangeLog
index 6861f6b19..e7698b70c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,8 @@
 2009-06-18  Eric Blake  <ebb9@byu.net>
 
+	hash: avoid no-op rehashing
+	* lib/hash.c (hash_rehash): Recognize useless rehash attempts.
+
 	hash: provide default callback functions
 	* lib/hash.c (raw_hasher, raw_comparator): New functions.
 	(hash_initialize): Use them as defaults.
diff --git a/lib/hash.c b/lib/hash.c
index 59f1ff0d0..f2123b4e4 100644
--- a/lib/hash.c
+++ b/lib/hash.c
@@ -862,6 +862,8 @@ hash_rehash (Hash_table *table, size_t candidate)
 			       table->comparator, table->data_freer);
   if (new_table == NULL)
     return false;
+  if (new_table->n_buckets == table->n_buckets)
+    return true;
 
   /* Merely reuse the extra old space into the new table.  */
 #if USE_OBSTACK