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quagga 1.0.20160315

    1: /* jhash.h: Jenkins hash support.
    2:  *
    3:  * Copyright (C) 1996 Bob Jenkins (bob_jenkins@burtleburtle.net)
    4:  *
    5:  * http://burtleburtle.net/bob/hash/
    6:  *
    7:  * These are the credits from Bob's sources:
    8:  *
    9:  * lookup2.c, by Bob Jenkins, December 1996, Public Domain.
   10:  * hash(), hash2(), hash3, and mix() are externally useful functions.
   11:  * Routines to test the hash are included if SELF_TEST is defined.
   12:  * You can use this free for any purpose.  It has no warranty.
   13:  *
   14:  * Copyright (C) 2003 David S. Miller (davem@redhat.com)
   15:  *
   16:  * I've modified Bob's hash to be useful in the Linux kernel, and
   17:  * any bugs present are surely my fault.  -DaveM
   18:  */
   19: 
   20: #ifndef _QUAGGA_JHASH_H
   21: #define _QUAGGA_JHASH_H
   22: 
   23: /* The most generic version, hashes an arbitrary sequence
   24:  * of bytes.  No alignment or length assumptions are made about
   25:  * the input key.
   26:  */
   27: extern u_int32_t jhash(const void *key, u_int32_t length, u_int32_t initval);
   28: 
   29: /* A special optimized version that handles 1 or more of u_int32_ts.
   30:  * The length parameter here is the number of u_int32_ts in the key.
   31:  */
   32: extern u_int32_t jhash2(const u_int32_t *k, u_int32_t length, u_int32_t initval);
   33: 
   34: /* A special ultra-optimized versions that knows they are hashing exactly
   35:  * 3, 2 or 1 word(s).
   36:  *
   37:  * NOTE: In partilar the "c += length; __jhash_mix(a,b,c);" normally
   38:  *       done at the end is not done here.
   39:  */
   40: extern u_int32_t jhash_3words(u_int32_t a, u_int32_t b, u_int32_t c, u_int32_t initval);
   41: extern u_int32_t jhash_2words(u_int32_t a, u_int32_t b, u_int32_t initval);
   42: extern u_int32_t jhash_1word(u_int32_t a, u_int32_t initval);
   43: 
   44: #endif /* _QUAGGA_JHASH_H */