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@ -1,61 +1,35 @@ |
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/* $OpenBSD: swab.c,v 1.8 2008/03/15 21:54:09 ray Exp $ */ |
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/* $OpenBSD: swab.c,v 1.9 2014/12/11 23:05:38 tedu Exp $ */ |
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/* |
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* Copyright (c) 1988 Regents of the University of California. |
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* All rights reserved. |
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* Copyright (c) 2014 Ted Unangst <tedu@openbsd.org> |
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* |
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* This code is derived from software contributed to Berkeley by |
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* Jeffrey Mogul. |
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* Permission to use, copy, modify, and distribute this software for any |
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* purpose with or without fee is hereby granted, provided that the above |
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* copyright notice and this permission notice appear in all copies. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in the |
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* documentation and/or other materials provided with the distribution. |
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* 3. Neither the name of the University nor the names of its contributors |
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* may be used to endorse or promote products derived from this software |
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* without specific prior written permission. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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* SUCH DAMAGE. |
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES |
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR |
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF |
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
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*/ |
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#include <unistd.h> |
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void |
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swab(const void *from, void *to, size_t len) |
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swab(const void *__restrict from, void *__restrict to, ssize_t len) |
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{ |
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size_t n; |
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char *fp, *tp; |
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char temp; |
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const unsigned char *src = from; |
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unsigned char *dst = to; |
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unsigned char t0, t1; |
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n = (len / 2) + 1; |
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fp = (char *)from; |
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tp = (char *)to; |
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#define STEP do { \ |
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temp = *fp++; \ |
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*tp++ = *fp++; \ |
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*tp++ = temp; \ |
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} while (0) |
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/* round to multiple of 8 */ |
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while ((--n) & 07) |
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STEP; |
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n >>= 3; |
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if (n == 0) |
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return; |
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while (n-- != 0) { |
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STEP; STEP; STEP; STEP; |
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STEP; STEP; STEP; STEP; |
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while (len > 1) { |
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t0 = src[0]; |
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t1 = src[1]; |
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dst[0] = t1; |
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dst[1] = t0; |
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src += 2; |
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dst += 2; |
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len -= 2; |
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} |
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} |