View file File name : hash-string.c Content :/* Implements a string hashing function. Copyright (C) 1995-2016 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; }