http://www.ousob.com --- Legacy Redefined OuSob - File: /wwwroot/clipx/usr/include/linux/jhash.h

#ifndef _LINUX_JHASH_H #define _LINUX_JHASH_H /* jhash.h: Jenkins hash support. * * Copyright (C) 1996 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. * * Copyright (C) 2003 David S. Miller (davem@redhat.com) * * I've modified Bob's hash to be useful in the Linux kernel, and * any bugs present are surely my fault. -DaveM */ /* NOTE: Arguments are modified. */ #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); \ } /* The golden ration: an arbitrary value */ #define JHASH_GOLDEN_RATIO 0x9e3779b9 /* The most generic version, hashes an arbitrary sequence * of bytes. No alignment or length assumptions are made about * the input key. */ static inline u32 jhash(const void *key, u32 length, u32 initval) { u32 a, b, c, len; 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); 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); 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]; }; __jhash_mix(a,b,c); 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 jhash2(u32 *k, u32 length, u32 initval) { u32 a, b, c, len; a = b = JHASH_GOLDEN_RATIO; c = initval; len = length; while (len >= 3) { a += k[0]; b += k[1]; c += k[2]; __jhash_mix(a, b, c); k += 3; len -= 3; } c += length * 4; switch (len) { case 2 : b += k[1]; case 1 : a += k[0]; }; __jhash_mix(a,b,c); return c; } /* A special ultra-optimized versions that knows they are hashing exactly * 3, 2 or 1 word(s). * * NOTE: In partilar 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; __jhash_mix(a, b, c); return c; } static inline u32 jhash_2words(u32 a, u32 b, u32 initval) { return jhash_3words(a, b, 0, initval); } static inline u32 jhash_1word(u32 a, u32 initval) { return jhash_3words(a, 0, 0, initval); } #endif /* _LINUX_JHASH_H */