【C语言】模拟实现memmove函数（考虑内存重叠）

//模拟实现memmove函数（考虑内存重叠）
#include <stdio.h>
#include <assert.h>
#include <string.h>
void * memmove(void * dst, const void * src, int count)
{
void * ret = dst;
assert(dst);
assert(src);
if (dst <= src || (char *)dst >= ((char *)src + count))   //正常情况不发生重叠，从低到高
{
while (count--)
{
*(char *)dst = *(char *)src;
dst = (char *)dst + 1;
src = (char *)src + 1;
}
}
else                                                      //发生重叠，从低到高
{
dst = (char *)dst + count - 1;
src = (char *)src + count - 1;
while (count--)
{
*(char *)dst = *(char *)src;
dst = (char *)dst - 1;
src = (char *)src - 1;
}
}
return ret;
}
int main()
{
char p[] = "hello!";
char *q = "world";
memmove(p, q,strlen(q)+1 );
printf("%s\n", p);
return 0;
}