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/* $OpenBSD: memcpy.c,v 1.3 2017/08/14 17:10:02 guenther Exp $ */ |
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/*- |
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* Copyright (c) 1990 The Regents of the University of California. |
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* All rights reserved. |
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* |
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* This code is derived from software contributed to Berkeley by |
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* Chris Torek. |
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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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*/ |
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#include <string.h> |
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#include <stdlib.h> |
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#include <syslog.h> |
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/* |
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* sizeof(word) MUST BE A POWER OF TWO |
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* SO THAT wmask BELOW IS ALL ONES |
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*/ |
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typedef long word; /* "word" used for optimal copy speed */ |
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#define wsize sizeof(word) |
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#define wmask (wsize - 1) |
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static const char backwards_msg[] = ": backwards memcpy"; |
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/* |
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* Copy a block of memory, not handling overlap. |
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*/ |
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void * |
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memcpy(void *dst0, const void *src0, size_t length) |
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{ |
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char *dst = dst0; |
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const char *src = src0; |
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size_t t; |
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✓✓✓✓
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1230023320 |
if (length == 0 || dst == src) /* nothing to do */ |
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goto done; |
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✓✓✓✗ ✗✓ |
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if ((dst < src && dst + length > src) || |
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✓✓ |
568184475 |
(src < dst && src + length > dst)) { |
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char buf[1024]; |
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/* <10> is LOG_CRIT */ |
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strlcpy(buf, "<10>", sizeof buf); |
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/* Make sure progname does not fill the whole buffer */ |
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strlcat(buf, __progname, sizeof(buf) - sizeof backwards_msg); |
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strlcat(buf, backwards_msg, sizeof buf); |
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sendsyslog(buf, strlen(buf), LOG_CONS); |
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abort(); |
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} |
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/* |
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* Macros: loop-t-times; and loop-t-times, t>0 |
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*/ |
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#define TLOOP(s) if (t) TLOOP1(s) |
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#define TLOOP1(s) do { s; } while (--t) |
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/* |
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* Copy forward. |
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*/ |
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t = (long)src; /* only need low bits */ |
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✓✓ |
409216237 |
if ((t | (long)dst) & wmask) { |
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/* |
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* Try to align operands. This cannot be done |
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* unless the low bits match. |
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*/ |
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✓✓ |
308625723 |
if ((t ^ (long)dst) & wmask || length < wsize) |
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t = length; |
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else |
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t = wsize - (t & wmask); |
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308625723 |
length -= t; |
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✓✓ |
2417576302 |
TLOOP1(*dst++ = *src++); |
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} |
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/* |
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* Copy whole words, then mop up any trailing bytes. |
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*/ |
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t = length / wsize; |
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✓✓✓✓
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TLOOP(*(word *)dst = *(word *)src; src += wsize; dst += wsize); |
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t = length & wmask; |
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✓✓✓✓
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TLOOP(*dst++ = *src++); |
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done: |
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return (dst0); |
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} |
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DEF_STRONG(memcpy); |