/* ascii.c - ASCII table - Don Yang (uguu.org)

   02/28/00
                                                                           */
#include<ctype.h>
#include<stdio.h>

char table[256][4] = {
   "nul", "soh", "stx", "etx", "eot", "enq", "ack", "bel",
   "bs ", "tab", "lf ", "vt ", "np ", "cr ", "so ", "si ",
   "dle", "dc1", "dc2", "dc3", "dc4", "nak", "syn", "etb",
   "can", "em ", "eof", "esc", "fs ", "gs ", "rs ", "us " };

int main(int argc, char **argv)
{
   int i, j, c;
   int x, k, s, p, r;

   /* Parse arguments */
   x = k = s = p = r = 0;
   for(i = 1; i < argc; i++)
   {
      switch( tolower(argv[i][0]) )
      {
         case 'e':   k = 128;                         break;
         case 'x':   sscanf(argv[i] + 1, "%d", &x);   break;
         case 's':   sscanf(argv[i] + 1, "%d", &s);   break;
         case 'p':   sscanf(argv[i] + 1, "%d", &p);   break;
         case 'r':   r = 1;                           break;
         default:
            return
            puts("ASCII 1.1 (2/28/00) - Don Yang (uguu.org)\n\n"
                 "Usage: ascii [e] [x<key>] [s<key>] [p<key>] [r]\n"
                 "   e    Display extended characters\n"
                 "   x    Display XORed characters (by <key>)\n"
                 "   s    Preshift\n"
                 "   p    Postshift\n"
                 "   r    rot13\n"
                 );
      }
   }

   /* Initialize table */
   for(i = 32; i < 256; i++)
      sprintf(table[i], "%c  ", i);
   sprintf(table[127], "del");

   /* Print table */
   if( x + s + p + r == 0 )
   {
      /* Plain */
      puts("\ndec, hex, chr\n");
      for(i = 0; i < 16; i++)
      {
         for(j = 0; j < 128; j += 16)
            printf("%3d %02x %s", i + j + k, i + j + k, table[i + j + k]);
      }
   }
   else
   {
      /* Processed */
      printf("\ndec, chr, ");
      if( s )
      {
         if( p )
         {
            if( x )  /* s != 0, p != 0, x != 0 */
               printf("(((%s + %d) %% 256) ^ %d + %d) %% 256\n\n",
                  r ? "rot13(chr)" : "chr", s, x, p);
            else     /* s != 0, p != 0, x == 0 */
               printf("(((%s + %d) %% 256) + %d) %% 256\n\n",
                  r ? "rot13(chr)" : "chr", s, p);
         }
         else
         {
            if( x )  /* s != 0, p == 0, x != 0 */
               printf("((%s + %d) %% 256) ^ %d\n\n",
                  r ? "rot13(chr)" : "chr", s, x);
            else     /* s != 0, p == 0, x == 0 */
               printf("(%s + %d) %% 256\n\n", r ? "rot13(chr)" : "chr", s);
         }
      }
      else
      {
         if( p )
         {
            if( x )  /* s == 0, p != 0, x != 0 */
               printf("(%s ^ %d + %d) %% 256\n\n",
                  r ? "rot13(chr)" : "chr", x, p);
            else     /* s == 0, p != 0, x == 0 */
               printf("(%s + %d) %% 256\n\n", r ? "rot13(chr)" : "chr", p);
         }
         else
         {
            if( x )  /* s == 0, p == 0, x != 0 */
               printf("%s ^ %d\n\n", r ? "rot13(chr)" : "chr", x);
            else     /* s == 0, p == 0, x == 0 */
               puts("rot13(chr)\n");
         }
      }

      for(; s < 0; s += 256);
      for(; p < 0; p += 256);
      for(i = 0; i < 16; i++)
      {
         for(j = 0; j < 128; j += 16 )
         {
            c = i + j + k;
            if( r && isalpha(c) )
            {
               c = islower(c)
                  ?  ((c - 'a') + 13) % 26 + 'a'
                  :  ((c - 'A') + 13) % 26 + 'A';
            }
            printf("%3d %s%s",
               i + j + k, table[i + j + k],
               table[((((c + s) % 256) ^ x) + p) % 256]);
         }
      }
   }

   putchar('\n');
   return 0;
}