public int Check(string buffer, int i, string st)
        {
            if (state != st) return 0;
            if (i <= last_index) return 0;
            eNka.ResetMachine();
            int result = eNka.StartEngines(buffer[i]);
            if (result == -1) return -1;
            if (result == 1) return 1;
            int j = i + 1;
            for (; j < buffer.Length && (result = eNka.StartEngines(buffer[j])) == 0; j++);
            last_index = j;
            if (result == -1) return -1;
            else return j - i + 1;
        }