/*
- * Copyright (c) 2008, 2009, 2010, 2012 Nicira, Inc.
+ * 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.
extern "C" {
#endif
-/* This is the public domain lookup3 hash by Bob Jenkins from
- * http://burtleburtle.net/bob/c/lookup3.c, modified for style. */
-
static inline uint32_t
hash_rot(uint32_t x, int k)
{
return (x << k) | (x >> (32 - k));
}
-static inline void
-hash_mix(uint32_t *a, uint32_t *b, uint32_t *c)
+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)
{
- *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;
+ data *= 0xcc9e2d51;
+ data = hash_rot(data, 15);
+ data *= 0x1b873593;
+ return hash ^ data;
}
-static inline void
-hash_final(uint32_t *a, uint32_t *b, uint32_t *c)
+static inline uint32_t mhash_add(uint32_t hash, uint32_t data)
{
- *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);
+ hash = mhash_add__(hash, data);
+ hash = hash_rot(hash, 13);
+ return hash * 5 + 0xe6546b64;
}
-uint32_t hash_words(const uint32_t *, size_t n_word, uint32_t basis);
-uint32_t hash_2words(uint32_t, uint32_t);
-uint32_t hash_3words(uint32_t, uint32_t, uint32_t);
-uint32_t hash_bytes(const void *, size_t n_bytes, uint32_t basis);
+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.
- *
- * This hash is faster than hash_2words(), but it isn't as good when 'basis' is
- * important. So use this function for speed or hash_2words() for hash
- * quality. */
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
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
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)
+static inline uint32_t hash_2words(uint32_t x, uint32_t y)
{
- 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_bytes)
-{
- hash ^= n_bytes;
- hash ^= hash >> 16;
- hash *= 0x85ebca6b;
- hash ^= hash >> 13;
- hash *= 0xc2b2ae35;
- hash ^= hash >> 16;
- return hash;
+ return mhash_finish(mhash_add(mhash_add(x, 0), y), 4);
}
#ifdef __cplusplus
git://git.onelab.eu / sliver-openvswitch.git / blobdiff