text: /*	$OpenBSD: swab.c,v 1.8 2008/03/15 21:54:09 ray Exp $ */
  /*
   * Copyright (c) 1988 Regents of the University of California.
   * All rights reserved.
   *
   * This code is derived from software contributed to Berkeley by
   * Jeffrey Mogul.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. Neither the name of the University nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   */
  
  #include <unistd.h>
  
  void
  swab(const void *from, void *to, size_t len)
  {
  	size_t n;
  	char *fp, *tp;
  	char temp;
  
  	n = (len / 2) + 1;
  	fp = (char *)from;
  	tp = (char *)to;
  #define	STEP do {	\
  	temp = *fp++;	\
  	*tp++ = *fp++;	\
  	*tp++ = temp;	\
  } while (0)
  	/* round to multiple of 8 */
  	while ((--n) & 07)
  		STEP;
  	n >>= 3;
  	if (n == 0)
  		return;
  	while (n-- != 0) {
  		STEP; STEP; STEP; STEP;
  		STEP; STEP; STEP; STEP;
  	}
  }
  