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/*-
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 * Copyright (c) 1990, 1993
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 *        The Regents of the University of California.  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 <sys/cdefs.h>
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#include <string.h>
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/*
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 * Copy a block of memory, handling overlap.
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 * This is the routine that actually implements
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 * (the portable versions of) bcopy, memcpy, and memmove.
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 */
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#ifdef MEMCOPY
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void *
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memcpy(dst0, src0, length)
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#else
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#ifdef MEMMOVE
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void *
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memmove(dst0, src0, length)
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#else
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void
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bcopy(src0, dst0, length)
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#endif
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#endif
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        void *dst0;
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        const void *src0;
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        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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        if (length == 0 || dst == src)                /* nothing to do */
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                goto done;
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        if (((unsigned long)dst < (unsigned long)src) &&
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            ((unsigned long)dst < (unsigned long)src + length)) {
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                /* Copy backwards. */
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                src += length;
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                dst += length;
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                while (length--) {
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                        *--dst = *--src;
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                }
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        } else {
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                while (length--) {
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                        *dst++ = *src++;
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                }
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        }
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done:
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#if defined(MEMCOPY) || defined(MEMMOVE)
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        return (dst0);
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#else
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        return;
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#endif
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}