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      1 /*
      2  * util/storage/lookup3.h - header file for hashing functions.
      3  *
      4  * Copyright (c) 2007, NLnet Labs. All rights reserved.
      5  *
      6  * This software is open source.
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions
     10  * are met:
     11  *
     12  * Redistributions of source code must retain the above copyright notice,
     13  * this list of conditions and the following disclaimer.
     14  *
     15  * Redistributions in binary form must reproduce the above copyright notice,
     16  * this list of conditions and the following disclaimer in the documentation
     17  * and/or other materials provided with the distribution.
     18  *
     19  * Neither the name of the NLNET LABS nor the names of its contributors may
     20  * be used to endorse or promote products derived from this software without
     21  * specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     24  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     25  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     26  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     27  * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     28  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
     29  * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     30  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
     31  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
     32  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
     33  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     34  */
     35 
     36 /**
     37  * \file
     38  *
     39  * This file contains header definitions for the hash functions we use.
     40  * The hash functions are public domain (see lookup3.c).
     41  */
     42 
     43 #ifndef UTIL_STORAGE_LOOKUP3_H
     44 #define UTIL_STORAGE_LOOKUP3_H
     45 
     46 /**
     47  * Hash key made of 4byte chunks.
     48  * @param k: the key, an array of uint32_t values
     49  * @param length: the length of the key, in uint32_ts
     50  * @param initval: the previous hash, or an arbitrary value
     51  * @return: hash value.
     52  */
     53 uint32_t hashword(const uint32_t *k, size_t length, uint32_t initval);
     54 
     55 /**
     56  * Hash key data.
     57  * @param k: the key, array of uint8_t
     58  * @param length: the length of the key, in uint8_ts
     59  * @param initval: the previous hash, or an arbitrary value
     60  * @return: hash value.
     61  */
     62 uint32_t hashlittle(const void *k, size_t length, uint32_t initval);
     63 
     64 /**
     65  * Set the randomisation initial value, set this before threads start,
     66  * and before hashing stuff (because it changes subsequent results).
     67  * @param v: value
     68  */
     69 void hash_set_raninit(uint32_t v);
     70 
     71 #endif /* UTIL_STORAGE_LOOKUP3_H */
     72