/* hash-string.h - Description of GNU message catalog format: string hashing function. */ /* Copyright (C) 1995, 1997, 1998, 2000, 2001, 2005-2009 Free Software Foundation, Inc. This file is part of GNU Bash. Bash is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. Bash 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 General Public License for more details. You should have received a copy of the GNU General Public License along with Bash. If not, see <http://www.gnu.org/licenses/>. */ /* @@ end of prolog @@ */ #ifndef PARAMS # if __STDC__ || defined __GNUC__ || defined __SUNPRO_C || defined __cplusplus || __PROTOTYPES # 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 int hash_string PARAMS ((const char *__str_param)); static inline unsigned long int 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 int) *str++; g = hval & ((unsigned long int) 0xf << (HASHWORDBITS - 4)); if (g != 0) { hval ^= g >> (HASHWORDBITS - 8); hval ^= g; } } return hval; }