/****************************************************************************
* num2fsm.c
* David Boozer
* (v1.0) March 30, 1999
* (v1.1) April 28, 2000
*****************************************************************************
* Translate number representation of Turing machine into finite state machine
* representation of Turing machine.
****************************************************************************/

#include <stdio.h>

#define B0 0
#define B1 1
#define R0 2
#define R1 3
#define L0 4
#define L1 5
#define ER 6
#define XX 7
#define SP 8

int next [2][14] = {
  /*       0   1   2   3   4   5   6   7   8   9   10  11  12  13 */
  /* 0 */  0,  8,  3,  4,  5,  6,  7,  0,  9,  0,  11, 12, 0,  3,
  /* 1 */  1,  2,  0,  0,  1,  1,  1,  1,  0,  10, 13, 10, 10, 0
};

int action [2][14] = {
  /*       0   1   2   3   4   5   6   7   8   9   10  11  12  13 */
  /* 0 */  XX, XX, XX, XX, XX, XX, XX, ER, XX, ER, XX, XX, ER, XX,
  /* 1 */  XX, XX, SP, ER, R0, R1, L0, L1, ER, B1, XX, B0, B1, ER
};

void print_state (int state, int number, char *string) {
  printf ("%03d %d --> ", state>>1, state & 1);
  printf ("%03d %s\n", number, string);
}

int main (int argc, char *argv[]) {
  int state = 0, number = 0, n = 2;
  char ch;
  FILE *input_file;
  
  if (argc != 2) {
    fprintf (stderr, "Syntax: num2fsm <input file>\n");
    exit (0);
  }
  if ((input_file = fopen (argv[1], "r")) == NULL) {
    fprintf (stderr, "Error reading from file: %s\n", argv[1]);
    exit (0);
  }
  do {
    ch = fgetc (input_file);
    if ((ch == '0') || (ch == '1')) {
      switch (action[ch-'0'][state]) {
      case B0: number = number<<1 | 0; break;
      case B1: number = number<<1 | 1; break;
      case R0: print_state (n++, number, "0 R"); number = 0; break;
      case R1: print_state (n++, number, "1 R"); number = 0; break;
      case L0: print_state (n++, number, "0 L"); number = 0; break;
      case L1: print_state (n++, number, "1 L"); number = 0; break;
      case ER: fprintf (stderr, "Syntax error\n"); break;
      case SP: break;
      case XX: break;
      }
      state = next[ch-'0'][state];
    }
  } while (ch != EOF);
  fclose (input_file);
  return (0);
}