+ return x;
+}
+
+/* An attempt at a useful 1-bit hash function. Has not been analyzed for
+ * quality. */
+static inline uint32_t hash_boolean(bool x, uint32_t basis)
+{
+ const uint32_t P0 = 0xc2b73583; /* This is hash_int(1, 0). */
+ const uint32_t P1 = 0xe90f1258; /* This is hash_int(2, 0). */
+ return (x ? P0 : P1) ^ hash_rot(basis, 1);
+}
+
+static inline uint32_t hash_double(double x, uint32_t basis)
+{
+ uint32_t value[2];
+ BUILD_ASSERT_DECL(sizeof x == sizeof value);
+
+ memcpy(value, &x, sizeof value);
+ return hash_3words(value[0], value[1], basis);
+}
+
+static inline uint32_t hash_pointer(const void *p, uint32_t basis)
+{
+ /* Often pointers are hashed simply by casting to integer type, but that
+ * has pitfalls since the lower bits of a pointer are often all 0 for
+ * alignment reasons. It's hard to guess where the entropy really is, so
+ * we give up here and just use a high-quality hash function.
+ *
+ * The double cast suppresses a warning on 64-bit systems about casting to
+ * an integer to different size. That's OK in this case, since most of the
+ * entropy in the pointer is almost certainly in the lower 32 bits. */
+ return hash_int((uint32_t) (uintptr_t) p, basis);
+}
+
+/* Murmurhash by Austin Appleby,
+ * from http://code.google.com/p/smhasher/source/browse/trunk/MurmurHash3.cpp.
+ *
+ * The upstream license there says:
+ *
+ * // MurmurHash3 was written by Austin Appleby, and is placed in the public
+ * // domain. The author hereby disclaims copyright to this source code.
+ *
+ * Murmurhash is faster and higher-quality than the Jenkins lookup3 hash. When
+ * we have a little more familiarity with it, it's probably a good idea to
+ * switch all of OVS to it.
+ *
+ * For now, we have this implementation here for use by code that needs a hash
+ * that is convenient for use one word at a time, since the Jenkins lookup3
+ * hash works three words at a time.
+ *
+ * See mhash_words() for sample usage. */
+
+uint32_t mhash_words(const uint32_t data[], size_t n_words, uint32_t basis);
+
+static inline uint32_t mhash_add(uint32_t hash, uint32_t data)
+{
+ data *= 0xcc9e2d51;
+ data = hash_rot(data, 15);
+ data *= 0x1b873593;
+
+ hash ^= data;
+ hash = hash_rot(hash, 13);
+ return hash * 5 + 0xe6546b64;
+}
+
+static inline uint32_t mhash_finish(uint32_t hash, size_t n)
+{
+ hash ^= n * 4;
+ hash ^= hash_rot(hash, 16);
+ hash *= 0x85ebca6b;
+ hash ^= hash_rot(hash, 13);
+ hash *= 0xc2b2ae35;
+ hash ^= hash_rot(hash, 16);
+ return hash;
+}
+
+#ifdef __cplusplus