#include <string.h>
  
  void * memmove(void * dst, const void * src, size_t n) {
    char * destination = (char *)dst;
    char * source = (char *)src;
  
    if (source < destination && destination < source + n) {
      /* Copy backwards to avoid overwrites */
      source += n;
      destination += n;
      while (n--) {
        *--destination = *--source;
      }
    } else {
      while (n--) {
        *destination++ = *source++;
      }
    }
  
    return dst;
  }