| 1 | /* Description of GNU message catalog format: string hashing function.
|
|---|
| 2 | Copyright (C) 1995, 1997, 1998, 2000, 2001 Free Software Foundation, Inc.
|
|---|
| 3 |
|
|---|
| 4 | This program is free software; you can redistribute it and/or modify it
|
|---|
| 5 | under the terms of the GNU Library General Public License as published
|
|---|
| 6 | by the Free Software Foundation; either version 2, or (at your option)
|
|---|
| 7 | any later version.
|
|---|
| 8 |
|
|---|
| 9 | This program is distributed in the hope that it will be useful,
|
|---|
| 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|---|
| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|---|
| 12 | Library General Public License for more details.
|
|---|
| 13 |
|
|---|
| 14 | You should have received a copy of the GNU Library General Public
|
|---|
| 15 | License along with this program; if not, write to the Free Software
|
|---|
| 16 | Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
|
|---|
| 17 | USA. */
|
|---|
| 18 |
|
|---|
| 19 | /* @@ end of prolog @@ */
|
|---|
| 20 |
|
|---|
| 21 | #ifndef PARAMS
|
|---|
| 22 | # if __STDC__ || defined __GNUC__ || defined __SUNPRO_C || defined __cplusplus || __PROTOTYPES
|
|---|
| 23 | # define PARAMS(Args) Args
|
|---|
| 24 | # else
|
|---|
| 25 | # define PARAMS(Args) ()
|
|---|
| 26 | # endif
|
|---|
| 27 | #endif
|
|---|
| 28 |
|
|---|
| 29 | /* We assume to have `unsigned long int' value with at least 32 bits. */
|
|---|
| 30 | #define HASHWORDBITS 32
|
|---|
| 31 |
|
|---|
| 32 |
|
|---|
| 33 | /* Defines the so called `hashpjw' function by P.J. Weinberger
|
|---|
| 34 | [see Aho/Sethi/Ullman, COMPILERS: Principles, Techniques and Tools,
|
|---|
| 35 | 1986, 1987 Bell Telephone Laboratories, Inc.] */
|
|---|
| 36 | static unsigned long int hash_string PARAMS ((const char *__str_param));
|
|---|
| 37 |
|
|---|
| 38 | static inline unsigned long int
|
|---|
| 39 | hash_string (str_param)
|
|---|
| 40 | const char *str_param;
|
|---|
| 41 | {
|
|---|
| 42 | unsigned long int hval, g;
|
|---|
| 43 | const char *str = str_param;
|
|---|
| 44 |
|
|---|
| 45 | /* Compute the hash value for the given string. */
|
|---|
| 46 | hval = 0;
|
|---|
| 47 | while (*str != '\0')
|
|---|
| 48 | {
|
|---|
| 49 | hval <<= 4;
|
|---|
| 50 | hval += (unsigned long int) *str++;
|
|---|
| 51 | g = hval & ((unsigned long int) 0xf << (HASHWORDBITS - 4));
|
|---|
| 52 | if (g != 0)
|
|---|
| 53 | {
|
|---|
| 54 | hval ^= g >> (HASHWORDBITS - 8);
|
|---|
| 55 | hval ^= g;
|
|---|
| 56 | }
|
|---|
| 57 | }
|
|---|
| 58 | return hval;
|
|---|
| 59 | }
|
|---|
