prosperon/source/engine/thirdparty/tinycdb/cdb_hash.c

/* cdb_hash.c: cdb hashing routine
 *
 * This file is a part of tinycdb package.
 * Copyright (C) 2001-2023 Michael Tokarev <mjt+cdb@corpit.ru>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */

#include "cdb.h"

unsigned
cdb_hash(const void *buf, unsigned len)
{
  register const unsigned char *p = (const unsigned char *)buf;
  register const unsigned char *end = p + len;
  register unsigned hash = 5381;	/* start value */
  while (p < end)
    hash = (hash + (hash << 5)) ^ *p++;
  return hash;
}