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 @@ -1,58 +1,22 @@ /*- - * 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 */ #include 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; } }