#include <stdio.h>

void printvar(FILE *fp,char* s);
int bcd2int(char *bcd);
int bcd3int(char *bcd);
void printstring(FILE *fp,char* s);
void printchar(unsigned char c);
void swap4(char a[4]);
void swap2(char a[2]);

main (int argc, char* argv[]) {
  FILE *fp;
  unsigned int lineno;
  unsigned short int sitmp;
  unsigned char linelen;
  int linestart,lineend,linect;
  int headerlen = 512;
  unsigned char opcode;
  char stmp[256];		/* temporary string */
  unsigned char ctmp; 		/* temporary value */
  int itmp;
  float ftmp;
  unsigned char slen;		/* string length */
  int i;

  if ((fp = fopen(argv[1],"r")) == NULL) {
    fprintf(stderr,"error opening file\n");
    exit(1);
  }

  fseek(fp,512+32,SEEK_CUR);	/* skip LIF headers + file header */
  linect = 0;

  while (fread(&lineno,3,1,fp)) {
    lineno = bcd3int((char *) &lineno);
    fread(&linelen,1,1,fp);
    printf("line: %04d length: %03d filepos: %05d\n",
	   lineno,linelen,ftell(fp)-4-headerlen);
    lineend = ftell(fp) + linelen;
    while (ftell(fp) < lineend) {
      opcode = fgetc(fp);
      switch (opcode) {
      case 0001:
	printvar(fp,"<\\001 fetch scalar variable>");
	break;
      case 0002:
	printvar(fp,"<\\002 fetch array variable>");
	break;
      case 0003:
	printvar(fp,"<\\003 fetch string variable>");
	break;
      case 0004:		/* 8 byte real number */
	fread(&ftmp,8,1,fp);
	printf("<\\004 real>\n");
	break;
      case 0005:
	printstring(fp,"<\\005 string>");
	break;
      case 0006:
	printstring(fp,"<\\006 string>");
	break;
      case 0007:
	printf("<\\007 store string variable?>\n");
	break;
      case 0010:
	printf("<\\010 store numeric variable>\n");
	break;
      case 0011:
	printf("<\\011 1d integer? array subscript>\n");
	break;
      case 0012:
	printf("<\\012 2d integer? array subscript>\n");
	break;
      case 0013:
	printf("<\\013 1d real? array subscript>\n");
	break;
      case 0014:
	printf("<\\014 2d real? array subscript>\n");
	break;
      case 0016:
	printf("<\\016 end line>\n");
	linect++;
	break;
      case 0021:
	printvar(fp,"<\\021 fetch scalar variable address>");
	break;
      case 0022:
	printvar(fp,"<\\022 fetch array variable address>");
	break;
      case 0023:
	printvar(fp,"<\\023 fetch string variable address>");
	break;
      case 0024:
        printf("<\\024 store numeric, multiple assignment?>\n");
	break;
      case 0026:
	printvar(fp,"<\\026 FN call?>");
	printf(" (number of arguments: %02d)\n",fgetc(fp));
	break;
      case 0027:
	printvar(fp,"<\\027 FN call w/ integer parameter?>");
        fread(&sitmp,2,1,fp);
	swap2((unsigned char*) &sitmp);
	printf("(parameter: %d)\n",sitmp);
	break;
      case 0030:
	printf("<\\030 GOTO line>");
	fread(&itmp,3,1,fp);
	printf("%05d\n",bcd3int((unsigned char* )&itmp));
	break;
      case 0032:
	printf("<\\032 integer>");
	fread(&itmp,3,1,fp);
	itmp = bcd3int((char *) &itmp);
	printf("%d\n",itmp);
	break;
      case 0033:
	printf("<\\033 THEN>");
	fread(&itmp,3,1,fp);
	itmp = bcd3int((char *) &itmp);
	printf("%d\n",itmp);
	break;
      case 0034:
	printf("<\\034 ELSE>");
	fread(&itmp,3,1,fp);
	itmp = bcd3int((char *) &itmp);
	printf("%d\n",itmp);
	break;
      case 0041:
	printvar(fp,"<\\041 jump to string label?>");
	break;
      case 0100:
	printf("<\\100 @ (statement separator)>\n");
	break;
      case 0103:
	printf("<\\103 ON KEY#>\n");
	break;
      case 0107:
	printf("<\\107 CLEAR>\n");
	break;
      case 0126:
	printf("<\\126 DISP>\n");
	break;
      case 0132:
	printf("<\\132 GOTO line>");
	fread(&itmp,3,1,fp);
	printf("%05d\n",bcd3int((unsigned char* )&itmp));
	break;
      case 0133:
	printf("<\\135 unknown GOTO line>");
	fread(&itmp,3,1,fp);
	printf("%05d\n",bcd3int((unsigned char* )&itmp));
	break;
      case 0137:
	printf("<\\137 INPUT>\n");
	break;
      case 0153:
	printf("<\\153 PRINT>\n");
	break;
      case 0207:
	printvar(fp,"<\\207 unknown variable command w/ integer parameter?>");
	fread(&itmp,3,1,fp);
	printf("(second parameter: %05d\n",bcd3int((unsigned char* )&itmp));
	opcode = fgetc(fp);
	if (opcode != 003) {
	  printf("\\%03o unexpected parameter\n");
	  exit(1);
	} else {
	  printstring(fp,"(third parameter:");
	}
	break;
      case 0216:
	printf("<\\216 DISP USING>\n");
	break;
      case 0257:
	printstring(fp,"<\\257 unknown immediate string?>");
	break;
      case 0262:
	printvar(fp,"<\\262 unknown error command>");
	break;
      case 0270:
	printvar(fp,"<\\270 unknown variable command>");
	break;
      case 0300:
	printf("\\300 ");
	opcode = fgetc(fp);
	printf("\\%03o ",opcode);
	break;
      case 0347:
	printf("<\\347 unknown integer>");
	fread(&itmp,3,1,fp);
	itmp = bcd3int((char *) &itmp);
	printf("%d\n",itmp);
	break;
      case 0350:
	printf("<\\350 input numeric from keyboard>\n");
	break;
      case 0351:
	printf("<\\351 input string from keyboard>\n");
	break;
      case 0363:
	printvar(fp,"<\\363 unknown variable command>");
	break;
      case 0367:
	printf("\\367 ");
	opcode = fgetc(fp);
	printf("\\%03o ",opcode);
	break;
      case 0370:
	printf("\\370 ");
	opcode = fgetc(fp);
	switch (opcode) {
	case 0001:
	  printf("\\001 ");
	  opcode = fgetc(fp);
	  switch (opcode) {
	  case 0002:
	    printf("\\002 ");
	    break;
	  default:
	    fseek(fp,-1,SEEK_CUR);
	    break;
	  }
	  break;
	case 0320:
	  printf("\\320 ");
	  opcode = fgetc(fp);
	  printf("\\%03o ",opcode);
	  break;
	default:
	  fseek(fp,-1,SEEK_CUR);
	  break;
	}
	break;
      case 0371:
	printf("\\371 ");
	opcode = fgetc(fp);
	switch (opcode) {
	case 0022:
	  printf("\\022 ");
	  opcode = fgetc(fp);
	  printf("\\%03o ",opcode);
	  break;
	case 0032:
	  printf("\\032 ");
	  opcode = fgetc(fp);
	  printf("\\%03o ",opcode);
	  break;
	default:
	  fseek(fp,-1,SEEK_CUR);
	  break;
	}
	break;
      default:
	printchar(opcode);
	break;
      }
    }
    fseek(fp,lineend,SEEK_SET);	/* recover from parse error */
    printf("\n");
    if (lineno == 109999) {
      break;
    }
  }
  printf("linect: %d\n",linect);
}

void printchar(unsigned char c) {
  if ((c > 32) && (c < 127)) {
    printf("%c ",c);
  } else {
    printf("\\%03o ",c);
  }
}

int bcd1int(unsigned char *bcd) {
  return (((bcd[0] & 0xf0) >> 4) * 10 +
	  (bcd[0] & 0x0f));
}	

int bcd2int(char *bcd) {
  return (((bcd[0] & 0xf0) >> 4) * 10 +
	  (bcd[0] & 0x0f)  +
	  ((bcd[1] & 0xf0) >> 4) * 1000 +
	  (bcd[1] & 0x0f) * 100);
}	

int bcd3int(char *bcd) {
  return (//((bcd[0] & 0xf0) >> 4) * 10 +
	  (bcd[0] & 0x0f) *10000 +
	  ((bcd[1] & 0xf0) >> 4) * 1000 +
	  (bcd[1] & 0x0f) * 100 +
	  ((bcd[2] & 0xf0) >> 4) * 10 +
	  (bcd[2] & 0x0f) );
}	

void printvar(FILE *fp,char *s) {
  unsigned int slen;			/* variable length */
  char stmp[256];
  fread(&slen,4,1,fp);
  swap4((char *) &slen);
  if (slen > 255) {
    printf("%s",s);
    printf(" ***bogus string length: %d\n",slen);
    exit(1);
  }
  fread(stmp,slen,1,fp);
  stmp[slen] = '\0';
  printf("%s`%s'\n",s,stmp);
}

void printstring(FILE *fp,char* s) {
  int slen;
  char stmp[256];
  slen = fgetc(fp);
  fread(stmp,slen,1,fp);
  stmp[slen] = '\0';
  printf("%s`%s'\n",s,stmp);
}

void swap2(char a[2]) {
  char tmp;
  tmp = a[0];
  a[0] = a[1];
  a[1] = tmp;
}

void swap4(char a[4]) {
  char tmp;
  tmp = a[0];
  a[0] = a[3];
  a[3] = tmp;
  tmp = a[1];
  a[1] = a[2];
  a[2] = tmp;
}