/*
- * 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 <config.h>
#include "hash.h"
#include <string.h>
+#include "unaligned.h"
-/* Returns the hash of the 'n' 32-bit words at 'p', starting from 'basis'.
- * 'p' must be properly aligned. */
+/* Returns the hash of 'a', 'b', and 'c'. */
uint32_t
-hash_words(const uint32_t *p, size_t n, uint32_t basis)
+hash_3words(uint32_t a, uint32_t b, uint32_t c)
{
- uint32_t a, b, c;
+ return mhash_finish(mhash_add(mhash_add(mhash_add(a, 0), b), c), 12);
+}
- a = b = c = 0xdeadbeef + (((uint32_t) n) << 2) + basis;
+/* Returns the hash of the 'n' bytes at 'p', starting from 'basis'. */
+uint32_t
+hash_bytes(const void *p_, size_t n, uint32_t basis)
+{
+ const uint32_t *p = p_;
+ size_t orig_n = n;
+ uint32_t hash;
- while (n > 3) {
- a += p[0];
- b += p[1];
- c += p[2];
- HASH_MIX(a, b, c);
- n -= 3;
- p += 3;
+ hash = basis;
+ while (n >= 4) {
+ hash = mhash_add(hash, get_unaligned_u32(p));
+ n -= 4;
+ p += 1;
}
- switch (n) {
- case 3:
- c += p[2];
- /* fall through */
- case 2:
- b += p[1];
- /* fall through */
- case 1:
- a += p[0];
- HASH_FINAL(a, b, c);
- /* fall through */
- case 0:
- break;
+ if (n) {
+ uint32_t tmp = 0;
+
+ memcpy(&tmp, p, n);
+ hash = mhash_add__(hash, tmp);
}
- return c;
+
+ return mhash_finish(hash, orig_n);
}
-/* Returns the hash of the pair of aligned 32-bit words at 'p', starting from
- * 'basis'. */
+/* Returns the hash of the 'n' 32-bit words at 'p', starting from 'basis'.
+ * 'p' must be properly aligned. */
uint32_t
-hash_2words(const uint32_t *p, uint32_t basis)
+hash_words(const uint32_t p[], size_t n_words, uint32_t basis)
{
- uint32_t a, b, c;
-
- a = b = c = 0xdeadbeef + (2 << 2) + basis;
- b += p[1];
- a += p[0];
- HASH_FINAL(a, b, c);
+ uint32_t hash;
+ size_t i;
- return c;
+ hash = basis;
+ for (i = 0; i < n_words; i++) {
+ hash = mhash_add(hash, p[i]);
+ }
+ return mhash_finish(hash, n_words * 4);
}
-/* Returns the hash of the 'n' bytes at 'p', starting from 'basis'. */
uint32_t
-hash_bytes(const void *p_, size_t n, uint32_t basis)
+hash_double(double x, uint32_t basis)
{
- const uint8_t *p = p_;
- uint32_t a, b, c;
- uint32_t tmp[3];
-
- a = b = c = 0xdeadbeef + n + basis;
-
- while (n >= sizeof tmp) {
- memcpy(tmp, p, sizeof tmp);
- a += tmp[0];
- b += tmp[1];
- c += tmp[2];
- HASH_MIX(a, b, c);
- n -= sizeof tmp;
- p += sizeof tmp;
- }
-
- if (n) {
- tmp[0] = tmp[1] = tmp[2] = 0;
- memcpy(tmp, p, n);
- a += tmp[0];
- b += tmp[1];
- c += tmp[2];
- HASH_FINAL(a, b, c);
- }
+ uint32_t value[2];
+ BUILD_ASSERT_DECL(sizeof x == sizeof value);
- return c;
+ memcpy(value, &x, sizeof value);
+ return hash_3words(value[0], value[1], basis);
}