cLK/lk/lib/libc/string/memmove.c
2011-03-25 23:39:33 +02:00

94 lines
2.5 KiB
C

/*
** Copyright 2001, Travis Geiselbrecht. All rights reserved.
** Distributed under the terms of the NewOS License.
*/
/*
* Copyright (c) 2008 Travis Geiselbrecht
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files
* (the "Software"), to deal in the Software without restriction,
* including without limitation the rights to use, copy, modify, merge,
* publish, distribute, sublicense, and/or sell copies of the Software,
* and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#include <string.h>
#include <sys/types.h>
#if !_ASM_MEMMOVE
typedef long word;
#define lsize sizeof(word)
#define lmask (lsize - 1)
void *
memmove(void *dest, void const *src, size_t count)
{
char *d = (char *)dest;
const char *s = (const char *)src;
int len;
if(count == 0 || dest == src)
return dest;
if((long)d < (long)s) {
if(((long)d | (long)s) & lmask) {
// src and/or dest do not align on word boundary
if((((long)d ^ (long)s) & lmask) || (count < lsize))
len = count; // copy the rest of the buffer with the byte mover
else
len = lsize - ((long)d & lmask); // move the ptrs up to a word boundary
count -= len;
for(; len > 0; len--)
*d++ = *s++;
}
for(len = count / lsize; len > 0; len--) {
*(word *)d = *(word *)s;
d += lsize;
s += lsize;
}
for(len = count & lmask; len > 0; len--)
*d++ = *s++;
} else {
d += count;
s += count;
if(((long)d | (long)s) & lmask) {
// src and/or dest do not align on word boundary
if((((long)d ^ (long)s) & lmask) || (count <= lsize))
len = count;
else
len = ((long)d & lmask);
count -= len;
for(; len > 0; len--)
*--d = *--s;
}
for(len = count / lsize; len > 0; len--) {
d -= lsize;
s -= lsize;
*(word *)d = *(word *)s;
}
for(len = count & lmask; len > 0; len--)
*--d = *--s;
}
return dest;
}
#endif