| /* Implements a string hashing function. |
| Copyright (C) 1995-2018 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, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #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; |
| } |