text: #ifndef ACK_H
  #define ACK_H
  
  extern void ACK_init(unsigned long long int *num);
  extern void ACK_LastStep(unsigned long long int *num);
  extern void ACK_Set(unsigned long long int *num, char dst[], const char src[], unsigned long long int len);
  extern int ACK_Check(unsigned long long int *num, char src[], unsigned long long int *len);
  
  /************************************
   *	ACK encode format, x,o=[0-9]*	*
   ***********************************/
  #define ACK_ENCODE "AxxxxooooxxxxooooxxxxCxxxxxK"
  #define ACK_LEN ((unsigned long long int)strlen(ACK_ENCODE))
  #define ACK_NUM_MAX (20)
  #define ACK_FAIL (0)
  #define ACK_SUCCESS (1)
  #define ACK_REPEAT (-1)
  
  #endif
  