/*
- * Copyright (c) 2008, 2009 Nicira Networks.
+ * Copyright (c) 2008, 2009, 2010, 2012, 2013, 2014, 2016 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_bytes(const void *, size_t n_bytes, uint32_t basis);
+/* The hash input must be a word larger than 128 bits. */
+void hash_bytes128(const void *_, size_t n_bytes, uint32_t basis,
+ ovs_u128 *out);
-static inline uint32_t hash_string(const char *s, 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);
+static inline uint32_t hash_uint64(const uint64_t);
+static inline uint32_t hash_uint64_basis(const uint64_t x,
+ const uint32_t basis);
+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)
{
- return hash_bytes(s, strlen(s), basis);
+ data *= 0xcc9e2d51;
+ data = hash_rot(data, 15);
+ data *= 0x1b873593;
+ return hash ^ data;
}
-/* 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)
+static inline uint32_t mhash_add(uint32_t hash, uint32_t data)
{
- 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;
+ hash = mhash_add__(hash, data);
+ hash = hash_rot(hash, 13);
+ return hash * 5 + 0xe6546b64;
}
-/* 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)
+static inline uint32_t mhash_finish(uint32_t hash)
+{
+ hash ^= hash >> 16;
+ hash *= 0x85ebca6b;
+ hash ^= hash >> 13;
+ hash *= 0xc2b2ae35;
+ hash ^= hash >> 16;
+ return hash;
+}
+
+#if !(defined(__SSE4_2__) && defined(__x86_64__))
+/* Mhash-based implementation. */
+
+static inline uint32_t hash_add(uint32_t hash, uint32_t data)
{
- 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);
+ return mhash_add(hash, data);
}
-static inline uint32_t hash_double(double x, uint32_t basis)
+static inline uint32_t hash_add64(uint32_t hash, uint64_t data)
+{
+ return hash_add(hash_add(hash, data), data >> 32);
+}
+
+static inline uint32_t hash_finish(uint32_t hash, uint32_t final)
+{
+ return mhash_finish(hash ^ final);
+}
+
+/* Returns the hash of the 'n' 32-bit words at 'p', starting from 'basis'.
+ * 'p' must be properly aligned.
+ *
+ * This is inlined for the compiler to have access to the 'n_words', which
+ * in many cases is a constant. */
+static inline uint32_t
+hash_words_inline(const uint32_t p[], size_t n_words, uint32_t basis)
{
- uint32_t value[2];
- BUILD_ASSERT_DECL(sizeof x == sizeof value);
+ uint32_t hash;
+ size_t i;
- memcpy(value, &x, sizeof value);
- return hash_2words(value, basis);
+ hash = basis;
+ for (i = 0; i < n_words; i++) {
+ hash = hash_add(hash, p[i]);
+ }
+ return hash_finish(hash, n_words * 4);
+}
+
+static inline uint32_t
+hash_words64_inline(const uint64_t p[], size_t n_words, uint32_t basis)
+{
+ uint32_t hash;
+ size_t i;
+
+ hash = basis;
+ for (i = 0; i < n_words; i++) {
+ hash = hash_add64(hash, p[i]);
+ }
+ return hash_finish(hash, n_words * 8);
}
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 hash_finish(hash_add(hash_add(x, 0), y), 8);
+}
+
+static inline uint32_t hash_uint64_basis(const uint64_t x,
+ const uint32_t basis)
+{
+ return hash_finish(hash_add64(basis, x), 8);
+}
+
+static inline uint32_t hash_uint64(const uint64_t x)
+{
+ return hash_uint64_basis(x, 0);
+}
+
+#else /* __SSE4_2__ && __x86_64__ */
+#include <smmintrin.h>
+
+static inline uint32_t hash_add(uint32_t hash, uint32_t data)
+{
+ return _mm_crc32_u32(hash, data);
+}
+
+/* Add the halves of 'data' in the memory order. */
+static inline uint32_t hash_add64(uint32_t hash, uint64_t data)
+{
+ return _mm_crc32_u64(hash, data);
+}
+
+static inline uint32_t hash_finish(uint64_t hash, uint64_t final)
+{
+ /* The finishing multiplier 0x805204f3 has been experimentally
+ * derived to pass the testsuite hash tests. */
+ hash = _mm_crc32_u64(hash, final) * 0x805204f3;
+ return hash ^ (uint32_t)hash >> 16; /* Increase entropy in LSBs. */
+}
+
+/* Returns the hash of the 'n' 32-bit words at 'p_', starting from 'basis'.
+ * We access 'p_' as a uint64_t pointer, which is fine for __SSE_4_2__.
+ *
+ * This is inlined for the compiler to have access to the 'n_words', which
+ * in many cases is a constant. */
+static inline uint32_t
+hash_words_inline(const uint32_t p_[], size_t n_words, uint32_t basis)
+{
+ const uint64_t *p = (const void *)p_;
+ uint64_t hash1 = basis;
+ uint64_t hash2 = 0;
+ uint64_t hash3 = n_words;
+ const uint32_t *endp = (const uint32_t *)p + n_words;
+ const uint64_t *limit = p + n_words / 2 - 3;
+
+ while (p <= limit) {
+ hash1 = _mm_crc32_u64(hash1, p[0]);
+ hash2 = _mm_crc32_u64(hash2, p[1]);
+ hash3 = _mm_crc32_u64(hash3, p[2]);
+ p += 3;
+ }
+ switch (endp - (const uint32_t *)p) {
+ case 1:
+ hash1 = _mm_crc32_u32(hash1, *(const uint32_t *)&p[0]);
+ break;
+ case 2:
+ hash1 = _mm_crc32_u64(hash1, p[0]);
+ break;
+ case 3:
+ hash1 = _mm_crc32_u64(hash1, p[0]);
+ hash2 = _mm_crc32_u32(hash2, *(const uint32_t *)&p[1]);
+ break;
+ case 4:
+ hash1 = _mm_crc32_u64(hash1, p[0]);
+ hash2 = _mm_crc32_u64(hash2, p[1]);
+ break;
+ case 5:
+ hash1 = _mm_crc32_u64(hash1, p[0]);
+ hash2 = _mm_crc32_u64(hash2, p[1]);
+ hash3 = _mm_crc32_u32(hash3, *(const uint32_t *)&p[2]);
+ break;
+ }
+ return hash_finish(hash1, hash2 << 32 | hash3);
+}
+
+/* A simpler version for 64-bit data.
+ * 'n_words' is the count of 64-bit words, basis is 64 bits. */
+static inline uint32_t
+hash_words64_inline(const uint64_t p[], size_t n_words, uint32_t basis)
+{
+ uint64_t hash1 = basis;
+ uint64_t hash2 = 0;
+ uint64_t hash3 = n_words;
+ const uint64_t *endp = p + n_words;
+ const uint64_t *limit = endp - 3;
+
+ while (p <= limit) {
+ hash1 = _mm_crc32_u64(hash1, p[0]);
+ hash2 = _mm_crc32_u64(hash2, p[1]);
+ hash3 = _mm_crc32_u64(hash3, p[2]);
+ p += 3;
+ }
+ switch (endp - p) {
+ case 1:
+ hash1 = _mm_crc32_u64(hash1, p[0]);
+ break;
+ case 2:
+ hash1 = _mm_crc32_u64(hash1, p[0]);
+ hash2 = _mm_crc32_u64(hash2, p[1]);
+ break;
+ }
+ return hash_finish(hash1, hash2 << 32 | hash3);
+}
+
+static inline uint32_t hash_uint64_basis(const uint64_t x,
+ const uint32_t basis)
+{
+ /* '23' chosen to mix bits enough for the test-hash to pass. */
+ return hash_finish(hash_add64(basis, x), 23);
+}
+
+static inline uint32_t hash_uint64(const uint64_t x)
+{
+ return hash_uint64_basis(x, 0);
+}
+
+static inline uint32_t hash_2words(uint32_t x, uint32_t y)
+{
+ return hash_uint64((uint64_t)y << 32 | x);
+}
+
+static inline uint32_t hash_pointer(const void *p, uint32_t basis)
+{
+ return hash_uint64_basis((uint64_t) (uintptr_t) p, basis);
+}
+#endif
+
+uint32_t hash_words__(const uint32_t p[], size_t n_words, uint32_t basis);
+uint32_t hash_words64__(const uint64_t p[], size_t n_words, uint32_t basis);
+
+/* Inline the larger hash functions only when 'n_words' is known to be
+ * compile-time constant. */
+#if __GNUC__ >= 4
+static inline uint32_t
+hash_words(const uint32_t p[], size_t n_words, uint32_t basis)
+{
+ if (__builtin_constant_p(n_words)) {
+ return hash_words_inline(p, n_words, basis);
+ } else {
+ return hash_words__(p, n_words, basis);
+ }
+}
+
+static inline uint32_t
+hash_words64(const uint64_t p[], size_t n_words, uint32_t basis)
+{
+ if (__builtin_constant_p(n_words)) {
+ return hash_words64_inline(p, n_words, basis);
+ } else {
+ return hash_words64__(p, n_words, basis);
+ }
+}
+
+#else
+
+static inline uint32_t
+hash_words(const uint32_t p[], size_t n_words, uint32_t basis)
+{
+ return hash_words__(p, n_words, basis);
+}
+
+static inline uint32_t
+hash_words64(const uint64_t p[], size_t n_words, uint32_t basis)
+{
+ return hash_words64__(p, n_words, basis);
+}
+#endif
+
+static inline uint32_t
+hash_bytes32(const uint32_t p[], size_t n_bytes, uint32_t basis)
+{
+ return hash_words(p, n_bytes / 4, basis);
+}
+
+static inline uint32_t
+hash_bytes64(const uint64_t p[], size_t n_bytes, uint32_t basis)
+{
+ return hash_words64(p, n_bytes / 8, basis);
+}
+
+static inline uint32_t hash_string(const char *s, uint32_t basis)
+{
+ return hash_bytes(s, strlen(s), basis);
+}
+
+static inline uint32_t hash_int(uint32_t x, uint32_t basis)
+{
+ 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)
+{
+ 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);
+}
+
+#ifdef __cplusplus
+}
+#endif
+
#endif /* hash.h */
projects / cascardo / ovs.git / blobdiff