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/*
* Copyright (c) 2013-2014, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <stddef.h> /* size_t */
/*
* Fill @count bytes of memory pointed to by @dst with @val
*/
void *memset(void *dst, int val, size_t count)
{
char *ptr = dst;
while (count--)
*ptr++ = val;
return dst;
}
/*
* 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;
}
/*
* Copy @len bytes from @src to @dst
*/
void *memcpy(void *dst, const void *src, size_t len)
{
const char *s = src;
char *d = dst;
while (len--)
*d++ = *s++;
return dst;
}
/*
* 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;
}
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