X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=tests%2Ftest-hash.c;h=081e72383c2089c73c1c680b7d6ab45ab2d4b063;hb=003ce655b7116d18c86a74c50391e54990346931;hp=d53ba2eadd3a71fb5a233b932db574ce61d74a76;hpb=9879b94f4381a342c66489dae3b4d4150d0dce6b;p=sliver-openvswitch.git

diff --git a/tests/test-hash.c b/tests/test-hash.c
index d53ba2ead..081e72383 100644
--- a/tests/test-hash.c
+++ b/tests/test-hash.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2009, 2012 Nicira, Inc.
+ * Copyright (c) 2009, 2012, 2014 Nicira, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -20,6 +20,8 @@
 #include <stdlib.h>
 #include <string.h>
 #include "hash.h"
+#include "jhash.h"
+#include "ovstest.h"
 
 #undef NDEBUG
 #include <assert.h>
@@ -41,9 +43,9 @@ hash_words_cb(uint32_t input)
 }
 
 static uint32_t
-mhash_words_cb(uint32_t input)
+jhash_words_cb(uint32_t input)
 {
-    return mhash_words(&input, 1, 0);
+    return jhash_words(&input, 1, 0);
 }
 
 static uint32_t
@@ -110,8 +112,8 @@ check_3word_hash(uint32_t (*hash)(const uint32_t[], size_t, uint32_t),
     }
 }
 
-int
-main(void)
+static void
+test_hash_main(int argc OVS_UNUSED, char *argv[] OVS_UNUSED)
 {
     /* Check that all hashes computed with hash_words with one 1-bit (or no
      * 1-bits) set within a single 32-bit word have different values in all
@@ -130,7 +132,7 @@ main(void)
      * independence must be a bad assumption :-)
      */
     check_word_hash(hash_words_cb, "hash_words", 11);
-    check_word_hash(mhash_words_cb, "mhash_words", 11);
+    check_word_hash(jhash_words_cb, "jhash_words", 11);
 
     /* Check that all hash functions of with one 1-bit (or no 1-bits) set
      * within three 32-bit words have different values in their lowest 12
@@ -146,24 +148,26 @@ main(void)
      * so we are doing pretty well to not have any collisions in 12 bits.
      */
     check_3word_hash(hash_words, "hash_words");
-    check_3word_hash(mhash_words, "mhash_words");
+    check_3word_hash(jhash_words, "jhash_words");
 
     /* Check that all hashes computed with hash_int with one 1-bit (or no
      * 1-bits) set within a single 32-bit word have different values in all
-     * 14-bit consecutive runs.
+     * 12-bit consecutive runs.
      *
      * Given a random distribution, the probability of at least one collision
-     * in any set of 14 bits is approximately
+     * in any set of 12 bits is approximately
      *
-     *                      1 - ((2**14 - 1)/2**14)**C(33,2)
-     *                   == 1 - (16,383/16,834)**528
-     *                   =~ 0.031
+     *                      1 - ((2**12 - 1)/2**12)**C(33,2)
+     *                   == 1 - (4,095/4,096)**528
+     *                   =~ 0.12
      *
-     * There are 18 ways to pick 14 consecutive bits in a 32-bit word, so if we
+     * There are 20 ways to pick 12 consecutive bits in a 32-bit word, so if we
      * assumed independence then the chance of having no collisions in any of
-     * those 14-bit runs would be (1-0.03)**18 =~ 0.56.  This seems reasonable.
+     * those 12-bit runs would be (1-0.12)**20 =~ 0.078.  This refutes our
+     * assumption of independence, which makes it seem like a good hash
+     * function.
      */
-    check_word_hash(hash_int_cb, "hash_int", 14);
-
-    return 0;
+    check_word_hash(hash_int_cb, "hash_int", 12);
 }
+
+OVSTEST_REGISTER("test-hash", test_hash_main);