+--- a/include/linux/jhash.h
++++ b/include/linux/jhash.h
+@@ -3,80 +3,95 @@
+
+ /* jhash.h: Jenkins hash support.
+ *
+- * Copyright (C) 1996 Bob Jenkins (bob_jenkins@burtleburtle.net)
++ * Copyright (C) 2006. Bob Jenkins (bob_jenkins@burtleburtle.net)
+ *
+ * http://burtleburtle.net/bob/hash/
+ *
+ * These are the credits from Bob's sources:
+ *
+- * lookup2.c, by Bob Jenkins, December 1996, Public Domain.
+- * hash(), hash2(), hash3, and mix() 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 has no warranty.
++ * lookup3.c, by Bob Jenkins, May 2006, Public Domain.
+ *
+- * Copyright (C) 2003 David S. Miller (davem@redhat.com)
++ * 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 surely my fault. -DaveM
++ * any bugs present are my fault. Jozsef
+ */
+
+-/* NOTE: Arguments are modified. */
+-#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 -= b; a -= c; a ^= (c>>13); \
+- b -= c; b -= a; b ^= (a<<8); \
+- c -= a; c -= b; c ^= (b>>13); \
+- a -= b; a -= c; a ^= (c>>12); \
+- b -= c; b -= a; b ^= (a<<16); \
+- c -= a; c -= b; c ^= (b>>5); \
+- a -= b; a -= c; a ^= (c>>3); \
+- b -= c; b -= a; b ^= (a<<10); \
+- c -= a; c -= b; c ^= (b>>15); \
++ 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; \
+ }
+
+-/* The golden ration: an arbitrary value */
+-#define JHASH_GOLDEN_RATIO 0x9e3779b9
++/* __jhash_final - final mixing of 3 32-bit values (a,b,c) into c */
++#define __jhash_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); \
++}
++
++/* An arbitrary initial parameter */
++#define JHASH_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 input key. The result depends on endianness.
+ */
+ static inline u32 jhash(const void *key, u32 length, u32 initval)
+ {
+- u32 a, b, c, len;
++ u32 a,b,c;
+ const u8 *k = key;
+
+- len = length;
+- a = b = JHASH_GOLDEN_RATIO;
+- c = initval;
+-
+- while (len >= 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));
+-
+- __jhash_mix(a,b,c);
++ /* Set up the internal state */
++ a = b = c = JHASH_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));
++ __jhash_mix(a, b, c);
++ length -= 12;
+ k += 12;
+- len -= 12;
+ }
+
+- c += length;
+- switch (len) {
+- case 11: c += ((u32)k[10]<<24);
+- case 10: c += ((u32)k[9]<<16);
+- case 9 : c += ((u32)k[8]<<8);
+- case 8 : b += ((u32)k[7]<<24);
+- case 7 : b += ((u32)k[6]<<16);
+- case 6 : b += ((u32)k[5]<<8);
++ /* 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 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];
+- };
+-
+- __jhash_mix(a,b,c);
++ __jhash_final(a, b, c);
++ case 0 :
++ break;
++ }
+
+ return c;
+ }
+@@ -86,28 +101,31 @@ static inline u32 jhash(const void *key,
+ */
+ static inline u32 jhash2(const u32 *k, u32 length, u32 initval)
+ {
+- u32 a, b, c, len;
++ u32 a, b, c;
+
+- a = b = JHASH_GOLDEN_RATIO;
+- c = initval;
+- len = length;
++ /* Set up the internal state */
++ a = b = c = JHASH_GOLDEN_RATIO + (length<<2) + initval;
+
+- while (len >= 3) {
++ /* handle most of the key */
++ while (length > 3) {
+ a += k[0];
+ b += k[1];
+ c += k[2];
+ __jhash_mix(a, b, c);
+- k += 3; len -= 3;
++ length -= 3;
++ k += 3;
+ }
+
+- c += length * 4;
+-
+- switch (len) {
+- case 2 : b += k[1];
+- case 1 : a += k[0];
+- };
+-
+- __jhash_mix(a,b,c);
++ /* 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];
++ __jhash_final(a, b, c);
++ case 0: /* case 0: nothing left to add */
++ break;
++ }
+
+ return c;
+ }
+@@ -115,29 +133,26 @@ static inline u32 jhash2(const u32 *k, u
+
+ /* A special ultra-optimized versions that knows they are hashing exactly
+ * 3, 2 or 1 word(s).
+- *
+- * NOTE: In particular the "c += length; __jhash_mix(a,b,c);" normally
+- * done at the end is not done here.
+ */
+ static inline u32 jhash_3words(u32 a, u32 b, u32 c, u32 initval)
+ {
+- a += JHASH_GOLDEN_RATIO;
+- b += JHASH_GOLDEN_RATIO;
+- c += initval;
++ a += JHASH_GOLDEN_RATIO + initval;
++ b += JHASH_GOLDEN_RATIO + initval;
++ c += JHASH_GOLDEN_RATIO + initval;
+
+- __jhash_mix(a, b, c);
++ __jhash_final(a, b, c);
+
+ return c;
+ }
+
+ static inline u32 jhash_2words(u32 a, u32 b, u32 initval)
+ {
+- return jhash_3words(a, b, 0, initval);
++ return jhash_3words(0, a, b, initval);
+ }
+
+ static inline u32 jhash_1word(u32 a, u32 initval)
+ {
+- return jhash_3words(a, 0, 0, initval);
++ return jhash_3words(0, 0, a, initval);
+ }
+
+ #endif /* _LINUX_JHASH_H */
projects / openwrt.git / blobdiff