【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
", p);
	return 0;
}