1 /* Copyright (c) 1997-2013 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Thorsten Kukuk <kukuk@suse.de>, 1997.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
19 #include <rpcsvc/nis.h>
21 /* This is from libc/db/hash/hash_func.c, hash3 is static there */
23 * This is INCREDIBLY ugly, but fast. We break the string up into 8 byte
24 * units. On the first time through the loop we get the "leftover bytes"
25 * (strlen % 8). On every other iteration, we perform 8 HASHC's so we handle
26 * all 8 bytes. Essentially, this saves us 7 cmp & branch instructions. If
27 * this routine is heavily used enough, it's worth the ugly coding.
29 * OZ's original sdbm hash
32 __nis_hash (const void *keyarg
, register size_t len
)
34 register const u_char
*key
;
38 #define HASHC h = *key++ + 65599 * h
44 loop
= (len
+ 8 - 1) >> 3;
45 switch (len
& (8 - 1))