Find file
Fetching contributors…
Cannot retrieve contributors at this time
60 lines (49 sloc) 1.75 KB
/* Implements a string hashing function.
Copyright (C) 1995, 1997 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
GNU General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
/* @@ end of prolog @@ */
#ifndef PARAMS
# if __STDC__
# define PARAMS(Args) Args
# else
# define PARAMS(Args) ()
# endif
/* We assume to have `unsigned long int' value with at least 32 bits. */
/* 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;