/* Implements a string hashing function. Copyright (C) 1995, 1997 Free Software Foundation, Inc. This file is part of the GNU C Library. Its master source is NOT part of the C library, however. The GNU C Library 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 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 Library General Public License for more details. You should have received a copy of the GNU Library General Public License along with the GNU C Library; see the file COPYING.LIB. 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 PARAMS # if __STDC__ # define PARAMS(Args) Args # else # define PARAMS(Args) () # endif #endif /* 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 unsigned long hash_string PARAMS ((const char *__str_param)); static inline unsigned long hash_string (str_param) 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 long) *str++; g = hval & ((unsigned long) 0xf << (HASHWORDBITS - 4)); if (g != 0) { hval ^= g >> (HASHWORDBITS - 8); hval ^= g; } } return hval; }