81 lines
2.5 KiB
C
81 lines
2.5 KiB
C
|
/* $NetBSD: swab.c,v 1.18 2011/01/04 17:14:07 martin Exp $ */
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Copyright (c) 1988, 1993
|
||
|
|
* The 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 <sys/cdefs.h>
|
||
|
|
#if defined(LIBC_SCCS) && !defined(lint)
|
||
|
|
#if 0
|
||
|
|
static char sccsid[] = "@(#)swab.c 8.1 (Berkeley) 6/4/93";
|
||
|
|
#else
|
||
|
|
__RCSID("$NetBSD: swab.c,v 1.18 2011/01/04 17:14:07 martin Exp $");
|
||
|
|
#endif
|
||
|
|
#endif /* LIBC_SCCS and not lint */
|
||
|
|
|
||
|
|
#include <assert.h>
|
||
|
|
#include <unistd.h>
|
||
|
|
|
||
|
|
void
|
||
|
|
swab(const void * __restrict from, void * __restrict to, ssize_t len)
|
||
|
|
{
|
||
|
|
char temp;
|
||
|
|
const char *fp;
|
||
|
|
char *tp;
|
||
|
|
|
||
|
|
if (len <= 1)
|
||
|
|
return;
|
||
|
|
|
||
|
|
_DIAGASSERT(from != NULL);
|
||
|
|
_DIAGASSERT(to != NULL);
|
||
|
|
|
||
|
|
len /= 2;
|
||
|
|
fp = (const char *)from;
|
||
|
|
tp = (char *)to;
|
||
|
|
#define STEP temp = *fp++,*tp++ = *fp++,*tp++ = temp
|
||
|
|
|
||
|
|
if (__predict_false(len == 1)) {
|
||
|
|
STEP;
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* round to multiple of 8 */
|
||
|
|
while ((--len % 8) != 0)
|
||
|
|
STEP;
|
||
|
|
len /= 8;
|
||
|
|
if (len == 0)
|
||
|
|
return;
|
||
|
|
while (len-- != 0) {
|
||
|
|
STEP; STEP; STEP; STEP;
|
||
|
|
STEP; STEP; STEP; STEP;
|
||
|
|
}
|
||
|
|
}
|