138 lines
4.1 KiB
C
138 lines
4.1 KiB
C
/* $NetBSD: memmove.c,v 1.2 1998/01/09 03:16:19 perry Exp $ */
|
|
|
|
/*-
|
|
* Copyright (c) 1990, 1993
|
|
* The Regents of the University of California. All rights reserved.
|
|
*
|
|
* This code is derived from software contributed to Berkeley by
|
|
* Chris Torek.
|
|
*
|
|
* 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. All advertising materials mentioning features or use of this software
|
|
* must display the following acknowledgement:
|
|
* This product includes software developed by the University of
|
|
* California, Berkeley and its contributors.
|
|
* 4. 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.
|
|
*/
|
|
|
|
#if defined(LIBC_SCCS) && !defined(lint)
|
|
static char sccsid[] = "@(#)bcopy.c 8.1 (Berkeley) 6/4/93";
|
|
#endif /* LIBC_SCCS and not lint */
|
|
|
|
#ifdef HAVE_CONFIG_H
|
|
# include <config.h>
|
|
#endif
|
|
|
|
#ifndef HAVE_MEMMOVE
|
|
#ifdef HAVE_SYS_TYPES_H
|
|
#include <sys/types.h>
|
|
#endif
|
|
#include <string.h>
|
|
|
|
/*
|
|
* sizeof(word) MUST BE A POWER OF TWO
|
|
* SO THAT wmask BELOW IS ALL ONES
|
|
*/
|
|
typedef int word; /* "word" used for optimal copy speed */
|
|
|
|
#define wsize sizeof(word)
|
|
#define wmask (wsize - 1)
|
|
|
|
/*
|
|
* Copy a block of memory, handling overlap.
|
|
* This is the routine that actually implements
|
|
* (the portable versions of) bcopy, memcpy, and memmove.
|
|
*/
|
|
void *
|
|
memmove(dst0, src0, length)
|
|
void *dst0;
|
|
const void *src0;
|
|
register size_t length;
|
|
{
|
|
register char *dst = dst0;
|
|
register const char *src = src0;
|
|
register size_t t;
|
|
|
|
if (length == 0 || dst == src) /* nothing to do */
|
|
goto done;
|
|
|
|
/*
|
|
* Macros: loop-t-times; and loop-t-times, t>0
|
|
*/
|
|
#define TLOOP(s) if (t) TLOOP1(s)
|
|
#define TLOOP1(s) do { s; } while (--t)
|
|
|
|
if ((unsigned long)dst < (unsigned long)src) {
|
|
/*
|
|
* Copy forward.
|
|
*/
|
|
t = (int)src; /* only need low bits */
|
|
if ((t | (int)dst) & wmask) {
|
|
/*
|
|
* Try to align operands. This cannot be done
|
|
* unless the low bits match.
|
|
*/
|
|
if ((t ^ (int)dst) & wmask || length < wsize)
|
|
t = length;
|
|
else
|
|
t = wsize - (t & wmask);
|
|
length -= t;
|
|
TLOOP1(*dst++ = *src++);
|
|
}
|
|
/*
|
|
* Copy whole words, then mop up any trailing bytes.
|
|
*/
|
|
t = length / wsize;
|
|
TLOOP(*(word *)dst = *(word *)src; src += wsize; dst += wsize);
|
|
t = length & wmask;
|
|
TLOOP(*dst++ = *src++);
|
|
} else {
|
|
/*
|
|
* Copy backwards. Otherwise essentially the same.
|
|
* Alignment works as before, except that it takes
|
|
* (t&wmask) bytes to align, not wsize-(t&wmask).
|
|
*/
|
|
src += length;
|
|
dst += length;
|
|
t = (int)src;
|
|
if ((t | (int)dst) & wmask) {
|
|
if ((t ^ (int)dst) & wmask || length <= wsize)
|
|
t = length;
|
|
else
|
|
t &= wmask;
|
|
length -= t;
|
|
TLOOP1(*--dst = *--src);
|
|
}
|
|
t = length / wsize;
|
|
TLOOP(src -= wsize; dst -= wsize; *(word *)dst = *(word *)src);
|
|
t = length & wmask;
|
|
TLOOP(*--dst = *--src);
|
|
}
|
|
done:
|
|
return (dst0);
|
|
}
|
|
#else
|
|
int memmove_bs;
|
|
#endif
|