1 /* Copyright (C) 1989-2014 Free Software Foundation, Inc.
2 Written by James Clark (jjc@jclark.com)
4 This file is part of groff.
6 groff is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation, either version 3 of the License, or
9 (at your option) any later version.
11 groff is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>. */
23 unsigned long hash_string(const char *s)
25 // This is the mythical Aho-Hopcroft-Ullman hash function.
26 // TODO: Improve. See http://www.haible.de/bruno/hashfunc.html
28 unsigned long h = 0, g;
32 if ((g = h & 0xf0000000) != 0) {
40 static const unsigned table_sizes[] = {
41 101, 503, 1009, 2003, 3001, 4001, 5003, 10007, 20011, 40009,
42 80021, 160001, 500009, 1000003, 2000003, 4000037, 8000009,
43 16000057, 32000011, 64000031, 128000003, 0
46 unsigned next_ptable_size(unsigned n)
49 for (p = table_sizes; *p <= n; p++)
51 fatal("cannot expand table");