/* $NetBSD: hash-string.h,v 1.1.1.1 2016/01/14 00:11:27 christos Exp $ */ /* Description of GNU message catalog format: string hashing function. Copyright (C) 1995, 1997-1998, 2000-2003 Free Software Foundation, Inc. This program is free software; you can redistribute it and/or modify it under the terms of the GNU Library 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 Library General Public License for more details. You should have received a copy of the GNU Library 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. */ /* @@ end of prolog @@ */ /* We assume to have `unsigned long int' value with at least 32 bits. */ #define HASHWORDBITS 32 /* 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 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; }