xref: /openbsd-src/lib/libelf/elf_hash.c (revision a1b5ec256a03e12d667837fca8bf42f20675916f)
1*a1b5ec25Sjsg /*-
2*a1b5ec25Sjsg  * Copyright (c) 2006,2008 Joseph Koshy
3*a1b5ec25Sjsg  * All rights reserved.
4*a1b5ec25Sjsg  *
5*a1b5ec25Sjsg  * Redistribution and use in source and binary forms, with or without
6*a1b5ec25Sjsg  * modification, are permitted provided that the following conditions
7*a1b5ec25Sjsg  * are met:
8*a1b5ec25Sjsg  * 1. Redistributions of source code must retain the above copyright
9*a1b5ec25Sjsg  *    notice, this list of conditions and the following disclaimer.
10*a1b5ec25Sjsg  * 2. Redistributions in binary form must reproduce the above copyright
11*a1b5ec25Sjsg  *    notice, this list of conditions and the following disclaimer in the
12*a1b5ec25Sjsg  *    documentation and/or other materials provided with the distribution.
13*a1b5ec25Sjsg  *
14*a1b5ec25Sjsg  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15*a1b5ec25Sjsg  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16*a1b5ec25Sjsg  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17*a1b5ec25Sjsg  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18*a1b5ec25Sjsg  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19*a1b5ec25Sjsg  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20*a1b5ec25Sjsg  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21*a1b5ec25Sjsg  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22*a1b5ec25Sjsg  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23*a1b5ec25Sjsg  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24*a1b5ec25Sjsg  * SUCH DAMAGE.
25*a1b5ec25Sjsg  */
26*a1b5ec25Sjsg 
27*a1b5ec25Sjsg #include <libelf.h>
28*a1b5ec25Sjsg 
29*a1b5ec25Sjsg #include "_libelf.h"
30*a1b5ec25Sjsg 
31*a1b5ec25Sjsg ELFTC_VCSID("$Id: elf_hash.c,v 1.1 2019/02/01 05:27:37 jsg Exp $");
32*a1b5ec25Sjsg 
33*a1b5ec25Sjsg /*
34*a1b5ec25Sjsg  * This elf_hash function is defined by the System V ABI.
35*a1b5ec25Sjsg  */
36*a1b5ec25Sjsg 
37*a1b5ec25Sjsg unsigned long
elf_hash(const char * name)38*a1b5ec25Sjsg elf_hash(const char *name)
39*a1b5ec25Sjsg {
40*a1b5ec25Sjsg 	unsigned long h, t;
41*a1b5ec25Sjsg 	const unsigned char *s;
42*a1b5ec25Sjsg 
43*a1b5ec25Sjsg 	s = (const unsigned char *) name;
44*a1b5ec25Sjsg 	h = t = 0;
45*a1b5ec25Sjsg 
46*a1b5ec25Sjsg 	for (; *s != '\0'; h = h & ~t) {
47*a1b5ec25Sjsg 		h = (h << 4) + *s++;
48*a1b5ec25Sjsg 		t = h & 0xF0000000UL;
49*a1b5ec25Sjsg 		if (t)
50*a1b5ec25Sjsg 			h ^= t >> 24;
51*a1b5ec25Sjsg 	}
52*a1b5ec25Sjsg 
53*a1b5ec25Sjsg 	return (h);
54*a1b5ec25Sjsg }
55