/*
- * Copyright (c) 2008, 2009 Nicira Networks.
+ * Copyright (c) 2008, 2009, 2010 Nicira Networks.
*
* 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"
+#ifdef __cplusplus
+extern "C" {
+#endif
+
/* This is the public domain lookup3 hash by Bob Jenkins from
* http://burtleburtle.net/bob/c/lookup3.c, modified for style. */
} 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);
+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 hash_string(const char *s, uint32_t basis)
}
/* This is Bob Jenkins' integer hash from
- * http://burtleburtle.net/bob/hash/integer.html, modified for style. */
+ * 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;
* 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). */
+ 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);
}
BUILD_ASSERT_DECL(sizeof x == sizeof value);
memcpy(value, &x, sizeof value);
- return hash_2words(value, basis);
+ return hash_3words(value[0], value[1], basis);
}
static inline uint32_t hash_pointer(const void *p, uint32_t basis)
return hash_int((uint32_t) (uintptr_t) p, basis);
}
+#ifdef __cplusplus
+}
+#endif
+
#endif /* hash.h */