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/* hash-string - Implements a string hashing function.
Copyright (C) 1995 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
#ifdef HAVE_VALUES_H
# include <values.h>
#endif
/* @@ end of prolog @@ */
#ifndef PARAMS
# if __STDC__
# define PARAMS(Args) Args
# else
# define PARAMS(Args) ()
# endif
#endif
/* We assume to have `unsigned long int' value with at least 32 bits. */
#define HASHWORDBITS 32
/* 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.] */
static unsigned long hash_string PARAMS ((const char *__str_param));
static inline unsigned long
hash_string (str_param)
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 long) *str++;
g = hval & ((unsigned long) 0xf << (HASHWORDBITS - 4));
if (g != 0)
{
hval ^= g >> (HASHWORDBITS - 8);
hval ^= g;
}
}
return hval;
}
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