Home | History | Annotate | Line # | Download | only in string
swab.c revision 1.11 
      1 /*	$NetBSD: swab.c,v 1.11 2001/05/22 18:56:33 christos Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1988, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * This code is derived from software contributed to Berkeley by
      8  * Jeffrey Mogul.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *	This product includes software developed by the University of
     21  *	California, Berkeley and its contributors.
     22  * 4. Neither the name of the University nor the names of its contributors
     23  *    may be used to endorse or promote products derived from this software
     24  *    without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     36  * SUCH DAMAGE.
     37  */
     38 
     39 #include <sys/cdefs.h>
     40 #if defined(LIBC_SCCS) && !defined(lint)
     41 #if 0
     42 static char sccsid[] = "@(#)swab.c	8.1 (Berkeley) 6/4/93";
     43 #else
     44 __RCSID("$NetBSD: swab.c,v 1.11 2001/05/22 18:56:33 christos Exp $");
     45 #endif
     46 #endif /* LIBC_SCCS and not lint */
     47 
     48 #include <assert.h>
     49 #include <unistd.h>
     50 
     51 void
     52 swab(const void *from, void *to, size_t len)
     53 {
     54 	char temp;
     55 	const char *fp;
     56 	char *tp;
     57 
     58 	_DIAGASSERT(from != NULL);
     59 	_DIAGASSERT(to != NULL);
     60 
     61 	len = (len / 2) + 1;
     62 	fp = (const char *)from;
     63 	tp = (char *)to;
     64 #define	STEP	temp = *fp++,*tp++ = *fp++,*tp++ = temp
     65 	/* round to multiple of 8 */
     66 	while ((--len & 07) != 0)
     67 		STEP;
     68 	len >>= 3;
     69 	if (len == 0)
     70 		return;
     71 	while (len-- != 0) {
     72 		STEP; STEP; STEP; STEP;
     73 		STEP; STEP; STEP; STEP;
     74 	}
     75 }
     76