xref: /freebsd/lib/libc/string/swab.c (revision 2f5cde3c64228de95d392e408f3198df9ba414a1)
158f0484fSRodney W. Grimes /*
258f0484fSRodney W. Grimes  * Copyright (c) 1988, 1993
358f0484fSRodney W. Grimes  *	The Regents of the University of California.  All rights reserved.
458f0484fSRodney W. Grimes  *
558f0484fSRodney W. Grimes  * This code is derived from software contributed to Berkeley by
658f0484fSRodney W. Grimes  * Jeffrey Mogul.
758f0484fSRodney W. Grimes  *
858f0484fSRodney W. Grimes  * Redistribution and use in source and binary forms, with or without
958f0484fSRodney W. Grimes  * modification, are permitted provided that the following conditions
1058f0484fSRodney W. Grimes  * are met:
1158f0484fSRodney W. Grimes  * 1. Redistributions of source code must retain the above copyright
1258f0484fSRodney W. Grimes  *    notice, this list of conditions and the following disclaimer.
1358f0484fSRodney W. Grimes  * 2. Redistributions in binary form must reproduce the above copyright
1458f0484fSRodney W. Grimes  *    notice, this list of conditions and the following disclaimer in the
1558f0484fSRodney W. Grimes  *    documentation and/or other materials provided with the distribution.
1658f0484fSRodney W. Grimes  * 3. All advertising materials mentioning features or use of this software
1758f0484fSRodney W. Grimes  *    must display the following acknowledgement:
1858f0484fSRodney W. Grimes  *	This product includes software developed by the University of
1958f0484fSRodney W. Grimes  *	California, Berkeley and its contributors.
2058f0484fSRodney W. Grimes  * 4. Neither the name of the University nor the names of its contributors
2158f0484fSRodney W. Grimes  *    may be used to endorse or promote products derived from this software
2258f0484fSRodney W. Grimes  *    without specific prior written permission.
2358f0484fSRodney W. Grimes  *
2458f0484fSRodney W. Grimes  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
2558f0484fSRodney W. Grimes  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
2658f0484fSRodney W. Grimes  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
2758f0484fSRodney W. Grimes  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
2858f0484fSRodney W. Grimes  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
2958f0484fSRodney W. Grimes  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
3058f0484fSRodney W. Grimes  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
3158f0484fSRodney W. Grimes  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
3258f0484fSRodney W. Grimes  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
3358f0484fSRodney W. Grimes  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
3458f0484fSRodney W. Grimes  * SUCH DAMAGE.
3558f0484fSRodney W. Grimes  */
3658f0484fSRodney W. Grimes 
3758f0484fSRodney W. Grimes #if defined(LIBC_SCCS) && !defined(lint)
3858f0484fSRodney W. Grimes static char sccsid[] = "@(#)swab.c	8.1 (Berkeley) 6/4/93";
3958f0484fSRodney W. Grimes #endif /* LIBC_SCCS and not lint */
40de5fe5d5SDavid E. O'Brien #include <sys/cdefs.h>
41de5fe5d5SDavid E. O'Brien __FBSDID("$FreeBSD$");
4258f0484fSRodney W. Grimes 
432f5cde3cSTom Rhodes #include <unistd.h>
4458f0484fSRodney W. Grimes 
4558f0484fSRodney W. Grimes void
462f5cde3cSTom Rhodes swab(const void * __restrict from, void * __restrict to, ssize_t len)
4758f0484fSRodney W. Grimes {
488fb3f3f6SDavid E. O'Brien 	unsigned long temp;
498fb3f3f6SDavid E. O'Brien 	int n;
508fb3f3f6SDavid E. O'Brien 	char *fp, *tp;
5158f0484fSRodney W. Grimes 
52c9ab23eeSRobert Drehmel 	n = len >> 1;
5358f0484fSRodney W. Grimes 	fp = (char *)from;
5458f0484fSRodney W. Grimes 	tp = (char *)to;
5558f0484fSRodney W. Grimes #define	STEP	temp = *fp++,*tp++ = *fp++,*tp++ = temp
5658f0484fSRodney W. Grimes 	/* round to multiple of 8 */
57c9ab23eeSRobert Drehmel 	for (; n & 0x7; --n)
5858f0484fSRodney W. Grimes 		STEP;
59c9ab23eeSRobert Drehmel 	for (n >>= 3; n > 0; --n) {
6058f0484fSRodney W. Grimes 		STEP; STEP; STEP; STEP;
6158f0484fSRodney W. Grimes 		STEP; STEP; STEP; STEP;
6258f0484fSRodney W. Grimes 	}
6358f0484fSRodney W. Grimes }
64