get Signal Quality SIM800 ?

Like taking value signal level without not use of library. Code library SIM800.h:

  SIM800L.println(F("AT+CSQ"));
  char *p = strstr(buffer, "CSQ: ");
  if (p) {
    int n = atoi(p + 2);
    if (n == 99 || n == -1) return 0;
    return n * 2 - 114;
  } else {
   return 0; 
  }