141 lines
2.6 KiB
C
141 lines
2.6 KiB
C
/*
|
|
* Copyright (c) 2013-2014, ARM Limited and Contributors. All rights reserved.
|
|
*
|
|
* SPDX-License-Identifier: BSD-3-Clause
|
|
*/
|
|
|
|
#include <stddef.h> /* size_t */
|
|
#include <limits.h>
|
|
#include <stdint.h>
|
|
#include <string.h>
|
|
|
|
/*
|
|
* Compare @len bytes of @s1 and @s2
|
|
*/
|
|
int memcmp(const void *s1, const void *s2, size_t len)
|
|
{
|
|
const unsigned char *s = s1;
|
|
const unsigned char *d = s2;
|
|
unsigned char sc;
|
|
unsigned char dc;
|
|
|
|
while (len--) {
|
|
sc = *s++;
|
|
dc = *d++;
|
|
if (sc - dc)
|
|
return (sc - dc);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Move @len bytes from @src to @dst
|
|
*/
|
|
void *memmove(void *dst, const void *src, size_t len)
|
|
{
|
|
/*
|
|
* The following test makes use of unsigned arithmetic overflow to
|
|
* more efficiently test the condition !(src <= dst && dst < str+len).
|
|
* It also avoids the situation where the more explicit test would give
|
|
* incorrect results were the calculation str+len to overflow (though
|
|
* that issue is probably moot as such usage is probably undefined
|
|
* behaviour and a bug anyway.
|
|
*/
|
|
if ((size_t)dst - (size_t)src >= len) {
|
|
/* destination not in source data, so can safely use memcpy */
|
|
return memcpy(dst, src, len);
|
|
} else {
|
|
/* copy backwards... */
|
|
const char *end = dst;
|
|
const char *s = (const char *)src + len;
|
|
char *d = (char *)dst + len;
|
|
while (d != end)
|
|
*--d = *--s;
|
|
}
|
|
return dst;
|
|
}
|
|
|
|
/*
|
|
* Scan @len bytes of @src for value @c
|
|
*/
|
|
void *memchr(const void *src, int c, size_t len)
|
|
{
|
|
const char *s = src;
|
|
|
|
while (len--) {
|
|
if (*s == c)
|
|
return (void *) s;
|
|
s++;
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
void *_memcpy(void *dst, const void *src, size_t len)
|
|
{
|
|
const char *s = src;
|
|
char *d = dst;
|
|
|
|
while (len--)
|
|
*d++ = *s++;
|
|
|
|
return dst;
|
|
}
|
|
|
|
#define SS (sizeof(size_t))
|
|
#define ALIGN (sizeof(size_t)-1)
|
|
#define ONES ((size_t)-1/UCHAR_MAX)
|
|
|
|
/*
|
|
* Fill @count bytes of memory pointed to by @dst with @val
|
|
*/
|
|
void *memset(void *dest, int c, size_t n)
|
|
{
|
|
unsigned char *s = dest;
|
|
|
|
c = (unsigned char)c;
|
|
|
|
for (; ((uintptr_t)s & ALIGN) && n; n--)
|
|
*s++ = c;
|
|
|
|
if (n) {
|
|
size_t *w, k = ONES * c;
|
|
|
|
for (w = (void *)s; n >= SS; n -= SS, w++)
|
|
*w = k;
|
|
for (s = (void *)w; n; n--, s++)
|
|
*s = c;
|
|
}
|
|
|
|
return dest;
|
|
}
|
|
|
|
/*
|
|
* Copy @len bytes from @src to @dst
|
|
*/
|
|
void *memcpy(void *restrict dest, const void *restrict src, size_t n)
|
|
{
|
|
unsigned char *d = dest;
|
|
const unsigned char *s = src;
|
|
|
|
if (((uintptr_t)d & ALIGN) != ((uintptr_t)s & ALIGN))
|
|
goto misaligned;
|
|
|
|
for (; ((uintptr_t)d & ALIGN) && n; n--)
|
|
*d++ = *s++;
|
|
if (n) {
|
|
size_t *wd = (void *)d;
|
|
const size_t *ws = (const void *)s;
|
|
|
|
for (; n >= SS; n -= SS)
|
|
*wd++ = *ws++;
|
|
d = (void *)wd;
|
|
s = (const void *)ws;
|
|
misaligned:
|
|
for (; n; n--)
|
|
*d++ = *s++;
|
|
}
|
|
return dest;
|
|
}
|