static void str_replace(char *str, const char *from, const char *to, int maxlen)
{
  char  *pstr   = str;
  int   fromlen = strlen(from);
  int   tolen   = strlen(to);
  
  while (*pstr != '\0' && pstr - str < maxlen) {
    if (strncmp(pstr, from, fromlen) != 0) {
      *pstr++;
      continue;
    }
    memmove(pstr + tolen, pstr + fromlen, maxlen - ((pstr + tolen) - str) - 1);
    memcpy(pstr, to, tolen);
    pstr += tolen;
  }
}