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 6861f6b198edef8137efcd0c5cfe13e8515f677a..e7698b70c254c5a556ae0e8d5af783e73939a8b0 100644 (file)
--- 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 59f1ff0d077d7796dc2f60c562382b880c5ef330..f2123b4e4cd78d571fed82edae27953d1cf3189b 100644 (file)
--- 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