+#include <ctype.h>
+#include <math.h>
+#include <stdint.h>
+#include <string.h>
+
+/* Based on http://burtleburtle.net/bob/c/lookup3.c, by Bob
+ Jenkins <bob_jenkins@burtleburtle.net>, as retrieved on April
+ 8, 2009. The license information there says the following:
+ "You can use this free for any purpose. It's in the public
+ domain. It has no warranty." and "You may use this code any
+ way you wish, private, educational, or commercial. It's
+ free." */
+
+#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)
+
+/* Returns a hash value for the N bytes starting at P, starting
+ from BASIS. */
+unsigned int
+hash_bytes (const void *p_, size_t n, unsigned int basis)
+{
+ const uint8_t *p = p_;
+ uint32_t a, b, c;
+ uint32_t tmp[3];
+
+ a = b = c = 0xdeadbeef + n + basis;
+
+ while (n >= 12)
+ {
+ memcpy (tmp, p, 12);
+ a += tmp[0];
+ b += tmp[1];
+ c += tmp[2];
+ HASH_MIX (a, b, c);
+ n -= 12;
+ p += 12;
+ }
+
+ if (n > 0)
+ {
+ memset (tmp, 0, 12);
+ memcpy (tmp, p, n);
+ a += tmp[0];
+ b += tmp[1];
+ c += tmp[2];
+ }
+
+ HASH_FINAL (a, b, c);
+ return c;
+}