1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
|
/* hash-string - Implements a string hashing function.
Copyright (C) 1995 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 BITSPERBYTE
# define BITSPERBYTE 8
#endif
#ifndef LONGBITS
# define LONGBITS (sizeof (long) * BITSPERBYTE)
#endif /* LONGBITS */
/* 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 inline unsigned long
hash_string (str_param)
const char *str_param;
{
unsigned long 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 << (LONGBITS - 4));
if (g != 0)
{
hval ^= g >> (LONGBITS - 8);
hval ^= g;
}
}
return hval;
}
|
