#include <stdio.h>

#define HDRLEN 512

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 printlno(FILE *fp, char *s);
void printfn (FILE *fp, char *s);
void printvarname(FILE *fp);

main (int argc, char* argv[]) {
  FILE *fp;
  unsigned short int lineno,sitmp;
  unsigned char linelen;
  int linestart,lineend,linect;
  int headerlen = HDRLEN;
  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+24,SEEK_CUR);	/* skip LIF headers + file header */
  linect = 0;

  while (fread(&lineno,2,1,fp)) {
    lineno = bcd2int((char *) &lineno);
    fread(&linelen,1,1,fp);
    printf("line: %04d length: %03d filepos: %05d\n",
	   lineno,linelen,ftell(fp)-3-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 */
	printf("<\\004 real>");
	fseek(fp,7,SEEK_CUR);	/* jump to last byte */
	ctmp = fgetc(fp);
	printf(" %1d.",(ctmp >> 4) & 0x0f); /* first sig digit */
	printf("%1d",ctmp & 0x0f);
	for (itmp = 1; itmp <= 5; itmp++) {
	  fseek(fp,-2,SEEK_CUR);
	  ctmp = fgetc(fp);
	  printf("%1d",(ctmp >> 4) & 0x0f);
	  printf("%1d",ctmp & 0x0f);
	}
	printf("E ");
	fseek(fp,-2,SEEK_CUR);
	ctmp = fgetc(fp);
	itmp = (ctmp >> 4) & 0x0f;
	printf("%1d",ctmp & 0x0f);
	fseek(fp,-2,SEEK_CUR);
	ctmp = fgetc(fp);
	printf("%1d",(ctmp >> 4) & 0x0f);
	printf("%1d",ctmp & 0x0f);
	printf(" *** sign bits ignored: 0x%1x\n",itmp);
	fseek(fp,7,SEEK_CUR);	/* skip to end of number */
	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: %03d)\n",fgetc(fp));
	break;
      case 0030:
	printlno(fp,"<\\030 IF .. GOTO (arithmetic?)>");
	break;
      case 0031:
	printf("<\\031 END>\n");
	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,2,1,fp);
	itmp = bcd2int((char *) &itmp);
	printf("%d\n",itmp);
	break;
      case 0034:
	printf("<\\034 ELSE>");
	fread(&itmp,2,1,fp);
	itmp = bcd2int((char *) &itmp);
	printf("%d\n",itmp);
	break;
      case 0052:
	printf("<\\052 * >\n");
	break;
      case 0053:
	printf("<\\052 + >\n");
	break;
      case 0055:
	printf("<\\055 - >\n");
	break;
      case 0057:
	printf("<\\057 / >\n");
	break;
      case 0060:
	printf("< ^ >\n");
	break;
      case 0065:
	printf("<\\065 = (string)>\n");
	break;
      case 0070:
	printf("<\\070 change sign>\n");
	break;
      case 0072:
	printf("<\\072 <= >\n");
	break;
      case 0073:
	printf("<\\073 >= >\n");
	break;
      case 0074:
	printf("<\\074 < >\n");
	break;
      case 0075:
	printf("<\\075 = (numeric)>\n");
	break;
      case 0076:
	printf("<\\076 > >\n");
	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 0125:
	printf("<\\125 DEG>\n");
	break;
      case 0126:
	printf("<\\126 DISP>\n");
	break;
      case 0132:
	printlno(fp,"<\\132 GOTO>");
	break;
      case 0133:
	printlno(fp,"<\\133 GOSUB>");
	break;
      case 0137:
	printf("<\\137 INPUT>\n");
	break;
      case 0142:
	printf("<\\142 LET>\n");
	break;
      case 0146:
	printf("<\\146 ON>\n");
	break;
      case 0153:
	printf("<\\153 PRINT>\n");
	break;
	//case 0213:
	//printlno(fp,"<\\213 USING>");
	//break;
      case 0154:
	printf("<\\0154 RAD>\n");
	break;
      case 0161:
	printf("<\\161 RETURN>\n");
	break;
	//case 0200:
	//printf("<\\200 FN dereference>\n");
	//break;
      case 0207:
	printvar(fp,"<\\207 DEF FN>");
	printlno(fp,"<line number after FN END>");
	printf("\\%03o function return type code?\n",fgetc(fp));
	printf("function argument: ");
	printvarname(fp);
	printf("*** DEF FN: skipping 8 bytes\n");
	fseek(fp,8,SEEK_CUR);
	break;
      case 0214:
	printf("<\\214 FOR>\n");
	break;
      case 0216:
	printf("<\\216 PRINT USING>\n");
	break;
      case 0217:
	printf("<\\217 NEXT>\n");
	break;
      case 0244:
	printf("<\\244 TO>\n");
	break;
      case 0245:
	printf("<\\245 OR>\n");
	break;
      case 0256:
	printf("<\\256 ATN2>\n");
	break;
      case 0260:
	printf("<\\260 SQR>\n");
	break;
      case 0274:
	printf("<\\274 EXP>\n");
	break;
      case 0277:
	printf("<\\277 LOG>\n");
	break;
      case 0311:
	printf("<\\311 PI>\n");
	break;
      case 0312:
	printf("<\\312 UPC$>\n");
	break;
      case 0315:
	printf("\\%03o ",opcode);
	opcode = fgetc(fp);
	printf("\\%03o ",opcode);
	opcode = fgetc(fp);
	printf("\\%03o ",opcode);
	printf(" unknown opcode followed by two bytes\n");
	break;
      case 0316:
	printf("<\\316 STEP>\n");
	break;
      case 0330:
	printf("<\\330 SIN>\n");
	break;
      case 0331:
	printf("<\\331 COS>\n");
	break;
      case 0347:
	printlno(fp,"<\\347 USING>");
	//printf("<\\347 USING>");
	//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 0352:
	printvar(fp,"<\\352 single line function assignment?>");
	break;
      case 0354:
	printf("<\\354 terminate output?>\n");
      case 0355:
	printf("<\\355 format and output numeric w/o CRLF?>\n");
	break;
      case 0356:
	printf("<\\356 format and output numeric w/ CRLF?>\n");
	break;
      case 0357:
	printf("<\\357 format and output string w/o CRLF?>\n");
	break;
      case 0360:
	printf("<\\360 format and output string w/ CRLF?>\n");
	break;
      case 0370:
	/* fallthrough */
      case 0371:
	printf("\\%03o ",opcode);
	printf("\\%03o ",fgetc(fp));
	printf("\\%03o\n",fgetc(fp));
	break;
     default:
       printf("\\%03o\n",opcode);
       //printchar(opcode);
       break;
      }
    }
    fseek(fp,lineend,SEEK_SET);	/* recover from parse error */
    printf("\n");
    if (lineno == 10999) {
      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)  +
	  ((bcd[1] & 0xf0) >> 4) * 1000 +
	  (bcd[1] & 0x0f) * 100 +
	  //((bcd[2] & 0xf0) >> 4) * 100000 +
	  (bcd[2] & 0x0f) * 10000);
}	

void printlno(FILE *fp, char *s) {
  unsigned short ustmp;
  long cpos;
  fread(&ustmp,2,1,fp);
  printf("%s",s);
  //printf("relative: %04d ",ustmp);
  cpos = ftell(fp);		/* current position */
  fseek(fp,ustmp+HDRLEN,SEEK_SET); /* seek to memory location */
  fread(&ustmp,2,1,fp);
  fseek(fp,cpos,SEEK_SET);	/* back to original spot */
  printf("%04d\n",bcd2int((char *) &ustmp));
}

void printfn (FILE *fp, char *s) {
  unsigned char name[2];
  unsigned int subidx[2];
  unsigned int nameextra;

  fread(name,2,1,fp);
  printf("%s",s);
  printf("`%c",(name[0] & 0x1f)+64);	/* convert 5 lower to ASCII */
  nameextra = (name[0] >> 5) & 0x07;
  subidx[1] = name[1] & 0x0f;   /* get BCD subscript */
  if (subidx[1] < 10) {
    printf("%1d",subidx[1]);
  }
  if (subidx[1] > 10) {
    printf("error: unknown BCD subscript on function: %02d\n",subidx[1]);
    exit(1);
  }
  printf("'");
  subidx[0] = (name[1] >> 4) & 0x0f;
  if ((subidx[0] != 0) || (nameextra != 0)) {
    printf(" (nameextra: %1d, BCD high bits: %02d)",
	   nameextra,subidx[0]);
  }
  printf("\n");
}


void printvar(FILE *fp, char *s) {
  unsigned short ustmp;
  long cpos;

  printf("%s",s);
  fread(&ustmp,2,1,fp);		/* get pointer into memory */
  cpos = ftell(fp);		/* store current position */
  fseek(fp,ustmp+HDRLEN,SEEK_SET); /* seek to memory location */
  printvarname(fp);
  fseek(fp,cpos,SEEK_SET);	/* back to original spot */
}

void printvarname(FILE *fp) {
  unsigned char name[2];
  unsigned int subidx[2];
  unsigned int nameextra;

  fread(name,2,1,fp);
  printf("`%c",(name[1] & 0x1f)+64); /* convert to ASCII */
  nameextra = (name[1] >> 5) & 0x07;
  subidx[1] = name[0] & 0x0f;   /* get BCD subscript */
  if (subidx[1] < 10) {
    printf("%1d",subidx[1]);
  }
  if (subidx[1] > 10) {
    printf("error: unknown BCD subscript on variable: %02d\n",subidx[1]);
    exit(1);
  }
  printf("'");
  subidx[0] = (name[0] >> 4) & 0x0f;
  if ((subidx[0] != 0) || (nameextra != 0)) {
    printf(" (nameextra: %1d, BCD high bits: %02d)",
	   nameextra,subidx[0]);
  }
  //  printf(" (%05d + 512 = %05d)",ustmp,ustmp+512);
  printf("\n");
}

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);
}