/*
- * Copyright (c) 2008, 2009 Nicira Networks.
+ * Copyright (c) 2008, 2009, 2010, 2012, 2013 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
#include <string.h>
#include "util.h"
-/* This is the public domain lookup3 hash by Bob Jenkins from
- * http://burtleburtle.net/bob/c/lookup3.c, modified for style. */
-
-#define HASH_ROT(x, k) (((x) << (k)) | ((x) >> (32 - (k))))
-
-#define HASH_MIX(a, b, c) \
- do { \
- a -= c; a ^= HASH_ROT(c, 4); c += b; \
- b -= a; b ^= HASH_ROT(a, 6); a += c; \
- c -= b; c ^= HASH_ROT(b, 8); b += a; \
- a -= c; a ^= HASH_ROT(c, 16); c += b; \
- b -= a; b ^= HASH_ROT(a, 19); a += c; \
- c -= b; c ^= HASH_ROT(b, 4); b += a; \
- } while (0)
-
-#define HASH_FINAL(a, b, c) \
- do { \
- c ^= b; c -= HASH_ROT(b, 14); \
- a ^= c; a -= HASH_ROT(c, 11); \
- b ^= a; b -= HASH_ROT(a, 25); \
- c ^= b; c -= HASH_ROT(b, 16); \
- a ^= c; a -= HASH_ROT(c, 4); \
- b ^= a; b -= HASH_ROT(a, 14); \
- c ^= b; c -= HASH_ROT(b, 24); \
- } while (0)
-
-uint32_t hash_words(const uint32_t *, size_t n_word, uint32_t basis);
-uint32_t hash_2words(const uint32_t *, uint32_t basis);
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+static inline uint32_t
+hash_rot(uint32_t x, int k)
+{
+ return (x << k) | (x >> (32 - k));
+}
+
+uint32_t hash_words(const uint32_t data[], size_t n_words, uint32_t basis);
uint32_t hash_bytes(const void *, size_t n_bytes, uint32_t basis);
+static inline uint32_t hash_int(uint32_t x, uint32_t basis);
+static inline uint32_t hash_2words(uint32_t, uint32_t);
+uint32_t hash_3words(uint32_t, uint32_t, uint32_t);
+
+static inline uint32_t hash_boolean(bool x, uint32_t basis);
+uint32_t hash_double(double, uint32_t basis);
+
+static inline uint32_t hash_pointer(const void *, uint32_t basis);
+static inline uint32_t hash_string(const char *, uint32_t 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.
+ *
+ * See hash_words() for sample usage. */
+
+static inline uint32_t mhash_add__(uint32_t hash, uint32_t data)
+{
+ data *= 0xcc9e2d51;
+ data = hash_rot(data, 15);
+ data *= 0x1b873593;
+ return hash ^ data;
+}
+
+static inline uint32_t mhash_add(uint32_t hash, uint32_t data)
+{
+ hash = mhash_add__(hash, data);
+ hash = hash_rot(hash, 13);
+ return hash * 5 + 0xe6546b64;
+}
+
+static inline uint32_t mhash_finish(uint32_t hash, size_t n_bytes)
+{
+ hash ^= n_bytes;
+ hash ^= hash >> 16;
+ hash *= 0x85ebca6b;
+ hash ^= hash >> 13;
+ hash *= 0xc2b2ae35;
+ hash ^= hash >> 16;
+ return hash;
+}
+
static inline uint32_t hash_string(const char *s, uint32_t basis)
{
return hash_bytes(s, strlen(s), basis);
}
-/* This is Bob Jenkins' integer hash from
- * http://burtleburtle.net/bob/hash/integer.html, modified for style. */
static inline uint32_t hash_int(uint32_t x, uint32_t basis)
{
- x -= x << 6;
- x ^= x >> 17;
- x -= x << 9;
- x ^= x << 4;
- x += basis;
- x -= x << 3;
- x ^= x << 10;
- x ^= x >> 15;
- return x;
+ return hash_2words(x, basis);
}
/* 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)
{
- enum { P0 = 0xc2b73583 }; /* This is hash_int(1, 0). */
- enum { 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)
-{
- BUILD_ASSERT_DECL(sizeof x == 8);
- return hash_2words((const uint32_t *) &x, 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_pointer(const void *p, uint32_t basis)
return hash_int((uint32_t) (uintptr_t) p, basis);
}
+static inline uint32_t hash_2words(uint32_t x, uint32_t y)
+{
+ return mhash_finish(mhash_add(mhash_add(x, 0), y), 4);
+}
+
+#ifdef __cplusplus
+}
+#endif
+
#endif /* hash.h */