1 /* Copyright (C) 1989, 1990, 1991, 1992, 2006, 2009
2 Free Software Foundation, Inc.
3 Written by James Clark (jjc@jclark.com)
5 This file is part of groff.
7 groff is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation, either version 3 of the License, or
10 (at your option) any later version.
12 groff is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
24 unsigned long hash_string(const char *s)
26 // This is the mythical Aho-Hopcroft-Ullman hash function.
27 // TODO: Improve. See http://www.haible.de/bruno/hashfunc.html
29 unsigned long h = 0, g;
33 if ((g = h & 0xf0000000) != 0) {
41 static const unsigned table_sizes[] = {
42 101, 503, 1009, 2003, 3001, 4001, 5003, 10007, 20011, 40009,
43 80021, 160001, 500009, 1000003, 2000003, 4000037, 8000009,
44 16000057, 32000011, 64000031, 128000003, 0
47 unsigned next_ptable_size(unsigned n)
50 for (p = table_sizes; *p <= n; p++)
52 fatal("cannot expand table");