/* Implements a string hashing function.

   Copyright (C) 1995-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#ifdef HAVE_CONFIG_H

# include <config.h>

#endif

/* Specification.  */

#include "hash-string.h"

/* Defines the so called `hashpjw' function by P.J. Weinberger

   [see Aho/Sethi/Ullman, COMPILERS: Principles, Techniques and Tools,

   1986, 1987 Bell Telephone Laboratories, Inc.]  */

unsigned long int

__hash_string (const char *str_param)

{

  unsigned long int hval, g;

  const char *str = str_param;

  /* Compute the hash value for the given string.  */

  hval = 0;

  while (*str != '\0')

    {

      hval <<= 4;

      hval += (unsigned char) *str++;

      g = hval & ((unsigned long int) 0xf << (HASHWORDBITS - 4));

      if (g != 0)

	{

	  hval ^= g >> (HASHWORDBITS - 8);

	  hval ^= g;

	}

    }

  return hval;

}