Re: [PATCH] Update jhash.h with the new version of Jenkins' hash

From: Patrick McHardy
Date: Thu Feb 12 2009 - 04:17:08 EST


Jozsef Kadlecsik wrote:
-#define __jhash_mix(a, b, c) \
+#define __rot(x,k) (((x)<<(k)) | ((x)>>(32-(k))))
+
+/* __jhash_mix - mix 3 32-bit values reversibly. */
+#define __jhash_mix(a,b,c) \
+{ \
+ a -= c; a ^= __rot(c, 4); c += b; \
+ b -= a; b ^= __rot(a, 6); a += c; \
+ c -= b; c ^= __rot(b, 8); b += a; \
+ a -= c; a ^= __rot(c,16); c += b; \
+ b -= a; b ^= __rot(a,19); a += c; \
+ c -= b; c ^= __rot(b, 4); b += a; \
+}

include/linux/bitops.h includes multiple rot variants. rol32()
looks approriate.
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