/* asctable.c

   this program does what it is supposed to do: print out the ASCII table
   from 000 to 128 :-) */

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>

char cntlkey[32][4] = {
  "NUL", "SOH", "STX", "ETX", "EOT", "ENQ", "ACK", "BEL", " BS", "TAB", " LF",
  " VT", " FF", " CR", " S0", " SI", "DLE", "DC1", "DC2", "DC3", "DC4", "NAK",
  "SYN", "ETB", "CAN", " EM", "SUB", "ESC", " FS", " GS", " RS", " US"};

int main(int argc, char *argv[])
{
  /* declaring variables */
  register int i, j, k;
  int arglen, ascii;
  char ch;

  /* parse command line */
  if (argc != 1 && argc != 2) {
    fprintf(stderr, "Usage: asctable [key/ascii]\n");
    exit(1);
  }
  else if (argc == 2) {
    /* how long is the input? */
    arglen = strlen(argv[1]);
    if ( arglen > 1 ) {
      /* more than 1 character, so this must be ASCII number */
      ascii = atoi(argv[1]);
      /* print it! */
      if ( iscntrl(ascii) )
	printf("The key corresponding to ascii value %s is a control key %s\n",
		argv[1], cntlkey[ascii]);
      else
	printf("The key corresponding to ascii value %s is %c\n", 
	        argv[1], ascii);
      return(0);
    }
    else {
      /* only one character, this could be a key or a number */
      ch = argv[1][0];
      if ( isdigit(ch) ) {
	/* so it's a number after all.... */
	printf("The key corresponding to ascii value %s is a control key %s\n",
		argv[1], cntlkey[atoi(argv[1])]);
	return(0);
      }
      else {
	/* so it is a key */
	printf("The ascii value for key %s is %03d\n", argv[1], ch);
	return(0);
      }
    }
  }

  /* so we don't have any options, print out the ascii table! */
  printf("\nASCII Table Generator / Lookup Tool\n");
  printf("Usage: asctable [ key / ascii ]\n");
  printf("For system control key, enclose use quotes\n");
  printf("Author: Leiming Qian <lqian@uiuc.edu>\n");
  printf("-------------------------------------\n");
  printf("ASCII");
  for (i=0;i<10;i++)
    printf("   %02d", i);
  printf("\n");
  printf("--------------------------------------------------------\n");
  for (j=0;j<26;j++) {
    printf("%03d  ", j*10);
    for (i=0;i<10-4*(j==25);i++) {
      /* check for control character */
      k = j*10+i;
      if ( iscntrl(k) ) {
	if ( k < 32 )
	  printf("  %s", cntlkey[k]);
	else
	  printf("     ");
      }
      else
	printf("    %c", k);
      }
    printf("\n");
  }
  printf("--------------------------------------------------------\n");
  printf("\n");

  return(0);
}