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+#ifndef _LINUX_JHASH3_H
+#define _LINUX_JHASH3_H
+
+/* jhash3.h: Jenkins hash support.
+ *
+ * Copyright (C) 2006. Bob Jenkins (bob_jenkins@burtleburtle.net)
+ *
+ * http://burtleburtle.net/bob/hash/
+ *
+ * These are the credits from Bob's sources:
+ *
+ * lookup3.c, by Bob Jenkins, May 2006, Public Domain.
+ *
+ * These are functions for producing 32-bit hashes for hash table lookup.
+ * hashword(), hashlittle(), hashlittle2(), hashbig(), mix(), and final()
+ * are externally useful functions. Routines to test the hash are included
+ * if SELF_TEST is defined. You can use this free for any purpose. It's in
+ * the public domain. It has no warranty.
+ *
+ * Copyright (C) 2009 Jozsef Kadlecsik (kadlec@blackhole.kfki.hu)
+ *
+ * I've modified Bob's hash to be useful in the Linux kernel, and
+ * any bugs present are my fault. Jozsef
+ */
+
+#define __rot(x,k) (((x)<<(k)) | ((x)>>(32-(k))))
+
+/* __jhash3_mix - mix 3 32-bit values reversibly. */
+#define __jhash3_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; \
+}
+
+/* __jhash3_final - final mixing of 3 32-bit values (a,b,c) into c */
+#define __jhash3_final(a,b,c) \
+{ \
+ c ^= b; c -= __rot(b,14); \
+ a ^= c; a -= __rot(c,11); \
+ b ^= a; b -= __rot(a,25); \
+ c ^= b; c -= __rot(b,16); \
+ a ^= c; a -= __rot(c,4); \
+ b ^= a; b -= __rot(a,14); \
+ c ^= b; c -= __rot(b,24); \
+}
+
+/* The golden ration: an arbitrary value */
+#define JHASH3_GOLDEN_RATIO 0xdeadbeef
+
+/* The most generic version, hashes an arbitrary sequence
+ * of bytes. No alignment or length assumptions are made about
+ * the input key. The result depends on endianness.
+ */
+static inline u32 jhash3(const void *key, u32 length, u32 initval)
+{
+ u32 a,b,c;
+ const u8 *k = key;
+
+ /* Set up the internal state */
+ a = b = c = JHASH3_GOLDEN_RATIO + length + initval;
+
+ /* all but the last block: affect some 32 bits of (a,b,c) */
+ while (length > 12) {
+ a += (k[0] + ((u32)k[1]<<8) + ((u32)k[2]<<16) + ((u32)k[3]<<24));
+ b += (k[4] + ((u32)k[5]<<8) + ((u32)k[6]<<16) + ((u32)k[7]<<24));
+ c += (k[8] + ((u32)k[9]<<8) + ((u32)k[10]<<16) + ((u32)k[11]<<24));
+ __jhash3_mix(a, b, c);
+ length -= 12;
+ k += 12;
+ }
+
+ /* last block: affect all 32 bits of (c) */
+ /* all the case statements fall through */
+ switch (length) {
+ case 12: c += (u32)k[11]<<24;
+ case 11: c += (u32)k[10]<<16;
+ case 10: c += (u32)k[9]<<8;
+ case 9 : c += k[8];
+ case 8 : b += (u32)k[7]<<24;
+ case 7 : b += (u32)k[6]<<16;
+ case 6 : b += (u32)k[5]<<8;
+ case 5 : b += k[4];
+ case 4 : a += (u32)k[3]<<24;
+ case 3 : a += (u32)k[2]<<16;
+ case 2 : a += (u32)k[1]<<8;
+ case 1 : a += k[0];
+ __jhash3_final(a, b, c);
+ case 0 :
+ break;
+ }
+
+ return c;
+}
+
+/* A special optimized version that handles 1 or more of u32s.
+ * The length parameter here is the number of u32s in the key.
+ */
+static inline u32 jhash3_words(const u32 *k, u32 length, u32 initval)
+{
+ u32 a, b, c;
+
+ /* Set up the internal state */
+ a = b = c = JHASH3_GOLDEN_RATIO + (length<<2) + initval;
+
+ /* handle most of the key */
+ while (length > 3) {
+ a += k[0];
+ b += k[1];
+ c += k[2];
+ __jhash3_mix(a, b, c);
+ length -= 3;
+ k += 3;
+ }
+
+ /* handle the last 3 u32's */
+ /* all the case statements fall through */
+ switch (length) {
+ case 3: c += k[2];
+ case 2: b += k[1];
+ case 1: a += k[0];
+ __jhash3_final(a, b, c);
+ case 0: /* case 0: nothing left to add */
+ break;
+ }
+
+ return c;
+}
+
+/* A special ultra-optimized versions that knows they are hashing exactly
+ * 3, 2 or 1 word(s).
+ */
+static inline u32 jhash3_3words(u32 a, u32 b, u32 c, u32 initval)
+{
+ a += JHASH3_GOLDEN_RATIO + initval;
+ b += JHASH3_GOLDEN_RATIO + initval;
+ c += JHASH3_GOLDEN_RATIO + initval;
+
+ __jhash3_final(a, b, c);
+
+ return c;
+}
+
+static inline u32 jhash3_2words(u32 a, u32 b, u32 initval)
+{
+ return jhash3_3words(0, a, b, initval);
+}
+
+static inline u32 jhash3_1word(u32 a, u32 initval)
+{
+ return jhash3_3words(0, 0, a, initval);
+}
+
+#endif /* _LINUX_JHASH3_H */