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Diffstat (limited to 'lib/jhash.h')
| -rw-r--r-- | lib/jhash.h | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/lib/jhash.h b/lib/jhash.h new file mode 100644 index 00000000..86a721c9 --- /dev/null +++ b/lib/jhash.h @@ -0,0 +1,44 @@ +/* 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 + */ + +#ifndef _QUAGGA_JHASH_H +#define _QUAGGA_JHASH_H + +/* The most generic version, hashes an arbitrary sequence + * of bytes. No alignment or length assumptions are made about + * the input key. + */ +u_int32_t jhash(void *key, u_int32_t length, u_int32_t initval); + +/* A special optimized version that handles 1 or more of u_int32_ts. + * The length parameter here is the number of u_int32_ts in the key. + */ +u_int32_t jhash2(u_int32_t *k, u_int32_t length, u_int32_t initval); + +/* 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. + */ +u_int32_t jhash_3words(u_int32_t a, u_int32_t b, u_int32_t c, u_int32_t initval); +u_int32_t jhash_2words(u_int32_t a, u_int32_t b, u_int32_t initval); +u_int32_t jhash_1word(u_int32_t a, u_int32_t initval); + +#endif /* _QUAGGA_JHASH_H */ |