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       1                 :             : /* cdb_hash.c: cdb hashing routine
       2                 :             :  *
       3                 :             :  * This file is a part of tinycdb package.
       4                 :             :  * Copyright (C) 2001-2023 Michael Tokarev <mjt+cdb@corpit.ru>
       5                 :             :  *
       6                 :             :  * Permission is hereby granted, free of charge, to any person obtaining a
       7                 :             :  * copy of this software and associated documentation files (the "Software"),
       8                 :             :  * to deal in the Software without restriction, including without limitation
       9                 :             :  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
      10                 :             :  * and/or sell copies of the Software, and to permit persons to whom the
      11                 :             :  * Software is furnished to do so, subject to the following conditions:
      12                 :             :  *
      13                 :             :  * The above copyright notice and this permission notice shall be included
      14                 :             :  * in all copies or substantial portions of the Software.
      15                 :             :  *
      16                 :             :  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
      17                 :             :  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
      18                 :             :  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
      19                 :             :  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
      20                 :             :  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
      21                 :             :  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
      22                 :             :  * DEALINGS IN THE SOFTWARE.
      23                 :             :  */
      24                 :             : 
      25                 :             : #include "cdb.h"
      26                 :             : 
      27                 :             : unsigned
      28                 :          71 : cdb_hash(const void *buf, unsigned len)
      29                 :             : {
      30                 :          71 :   register const unsigned char *p = (const unsigned char *)buf;
      31                 :          71 :   register const unsigned char *end = p + len;
      32                 :          71 :   register unsigned hash = 5381;        /* start value */
      33         [ +  + ]:         735 :   while (p < end)
      34                 :         664 :     hash = (hash + (hash << 5)) ^ *p++;
      35                 :          71 :   return hash;
      36                 :             : }