xref: /openbsd/lib/libc/string/swab.c (revision fc61954a)
1 /*	$OpenBSD: swab.c,v 1.9 2014/12/11 23:05:38 tedu Exp $ */
2 /*
3  * Copyright (c) 2014 Ted Unangst <tedu@openbsd.org>
4  *
5  * Permission to use, copy, modify, and distribute this software for any
6  * purpose with or without fee is hereby granted, provided that the above
7  * copyright notice and this permission notice appear in all copies.
8  *
9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16  */
17 #include <unistd.h>
18 
19 void
20 swab(const void *__restrict from, void *__restrict to, ssize_t len)
21 {
22 	const unsigned char *src = from;
23 	unsigned char *dst = to;
24 	unsigned char t0, t1;
25 
26 	while (len > 1) {
27 		t0 = src[0];
28 		t1 = src[1];
29 		dst[0] = t1;
30 		dst[1] = t0;
31 		src += 2;
32 		dst += 2;
33 		len -= 2;
34 	}
35 }
36