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- /* Implements a string hashing function.
- Copyright (C) 1995, 1997, 1998, 2000, 2003 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, write to the Free
- Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
- Boston, MA 02110-1301, USA. */
- #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;
- }
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