1 files changed, 11 insertions, 47 deletions

diff --git a/lib/libc/string/swab.c b/lib/libc/string/swab.c
index e3765fa08d07..2b044d68ca46 100644
--- a/lib/libc/string/swab.c
+++ b/lib/libc/string/swab.c
@@ -1,35 +1,6 @@
 /*-
- * SPDX-License-Identifier: BSD-3-Clause
- *
- * 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.
+ * SPDX-License-Identifier: BSD-2-Clause
+ * Copyright (c) 2024 rilysh <nightquick@proton.me>
  */
 
 #include <unistd.h>
@@ -37,22 +8,15 @@
 void
 swab(const void * __restrict from, void * __restrict to, ssize_t len)
 {
-	unsigned char temp;
-	size_t n;
-	const unsigned char *fp;
-	unsigned char *tp;
+	const unsigned char *f = from;
+	unsigned char *t = to;
 
-	if (len <= 0)
-		return;
-	n  = (size_t)len >> 1;
-	fp = (const unsigned char *)from;
-	tp = (unsigned char *)to;
-#define	STEP	temp = *fp++,*tp++ = *fp++,*tp++ = temp
-	/* round to multiple of 8 */
-	for (; n & 0x7; --n)
-		STEP;
-	for (n >>= 3; n > 0; --n) {
-		STEP; STEP; STEP; STEP;
-		STEP; STEP; STEP; STEP;
+	while (len > 1) {
+		t[0] = f[1];
+		t[1] = f[0];
+
+		f += 2;
+		t += 2;
+		len -= 2;
 	}
 }