/* A mix of simple utility functions for dealing with paper tapes.
   param 1 is the mode -- i.e. selects which utility
   param 2 is an input file -- usually raw bytes from a paper tape reader
   param 3 is anothe file name -- wither an output file, or a file to be compared

   Mode k, show KDF9 as characters
   Mode r, reverse the order of the bytes -- used after reading a tape in reverse to detect misreads
   Other modes -- explanation (some) in the source text
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>

#define BUFF_SIZE  819200

#ifndef O_BINARY
#define O_BINARY  0
#endif

int verbose = 0;

unsigned char buff[BUFF_SIZE], buff2[BUFF_SIZE];

/* KDF9 character code tables */
char ntab[] = " !\n!\t!!!!!!!!!!/0123456789_#;+-.!ABCDEFGHIJKLMNOPQRSTUVWXYZ!!~!!";

char stab[] = " !\n!\t!!!!!!!!!!:^[]<>=*%()_$;#*,!abcdefghijklmnopqrstuvwxyz!!~!!";

/* EDSAC 2 character code tables - sub10 is e and sub2 is # */
char ftab[] = "!f\r0r72s\n85/9(=ep43#6tn-1*)!.+ !";
char ltab[] = "!F\rORKUS\nLHAMZEDPGYWJTNBICX!VQ !";

void showchar(int c, char *buff)
{  int mask = 0x100;
   while  ( (mask = mask >> 1) >= 0x8 )
      if  ( (c & mask) != 0 )
         *(buff++) = 'o';
      else
         *(buff++) = ' ';
   *(buff++) = '.';
   while  ( (mask = mask >> 1) > 0 )
      if  ( (c & mask) != 0 )
         *(buff++) = 'o';
      else
         *(buff++) = ' ';
   *(buff++) = ' ';
   if  ( (c&0x7F) < ' ' )
      c = ' ';
   *(buff++) = c & 0x7F;
}

main(argc, argv)
int argc;
char **argv;
{  char *mode;

   if  ( argc < 3 )
      printf("Usage: %s mode file1 file2",
             *argv
            );

   else if  ( *(mode = argv[1]) == 'r' )      /* reverse the order of the bytes */
   {  int dvi = open(argv[2], O_RDONLY + O_BINARY);
      int dvo = open(argv[3], O_WRONLY + O_TRUNC + O_CREAT + O_BINARY);
      int n, i, m, w;
      n = read(dvi, buff, BUFF_SIZE);
      if  ( n > 0  &&  n < BUFF_SIZE )      // read all of file OK
      {  m = n/2;
         for  ( i = 0; i<m; i++ )
         {  w = buff[i];
            buff[i] = buff[n - 1 - i];
            buff[n - 1 - i] = w;
         }
         write(dvo, buff, n);
      }
      printf("Ending code = %d\n", n);
   }

   else if  ( *mode == 'c' )      /* compare ignoring initial and final nulls */
   {  int dvi = open(argv[2], O_RDONLY + O_BINARY);
      int dv2 = open(argv[3], O_RDONLY + O_BINARY);
      int n, i, m, w, d1, d2;
      n = read(dvi, buff, BUFF_SIZE);
      m = read(dv2, buff2, BUFF_SIZE);
      if  ( n > 0  &&  n < BUFF_SIZE )      // read all of file1 OK
      if  ( m > 0  &&  m < BUFF_SIZE )      // read all of file2 OK
      {  d1 = 0;
         d2 = 0;
         while  ( buff[++d1] == 0 ) ;
         while  ( buff2[++d2] == 0 ) ;

         printf("n = %d, d1 = %d :: m = %d, d2 = %d\n", n, d1, m, d2);

         while  ( d1 < n  &&  d2 < m  &&  buff[d1++] == buff2[d2++] ) ;
         if  ( d1 < n  &&  d2 < m )
         {  d1 --;   d2 --;
            printf("Mismatch d1 = %d, d2 = %d\n", d1, d2);
            printf("-------- %02X %02X %02X %02X %02X %02X %02X %02X %02X %02X\n",
                    buff[d1-1]&255, buff[d1]&255, buff[d1+1]&255, buff[d1+2]&255, buff[d1+3]&255,
                    buff[d1+4]&255, buff[d1+5]&255, buff[d1+6]&255, buff[d1+7]&255, buff[d1+8]&255);
            printf("-------- %02X %02X %02X %02X %02X %02X %02X %02X %02X %02X\n",
                    buff2[d1-1]&255, buff2[d1]&255, buff2[d1+1]&255, buff2[d1+2]&255, buff2[d1+3]&255,
                    buff2[d1+4]&255, buff2[d1+5]&255, buff2[d1+6]&255, buff2[d1+7]&255, buff2[d1+8]&255);
         }
      }
      printf("Ending code = %d/%d\n", n, m);
   }

   else if  ( *mode == 'k' )      /* show KDF9 tapes as characters */
   {  int dvi = open(argv[2], O_RDONLY + O_BINARY);
      int dvo = open(argv[3], O_WRONLY + O_TRUNC + O_CREAT + O_BINARY);
      int n, i, m, w;
      char *tab;
      tab = ntab;
   // printf("%c %c %c %c %c\n", ntab[32], ntab[33], ntab[34], ntab[35], ntab[36]);
   // printf("%c %c %c %c %c\n", stab[32], stab[33], stab[34], stab[35], stab[36]);
   // printf("%c %c %c %c %c\n", tab[32], tab[33], tab[34], tab[35], tab[36]);
      n = read(dvi, buff, BUFF_SIZE);
      m = 0;
      if  ( n > 0  &&  n < BUFF_SIZE )      // read all of file OK
      {  for  ( i = 0; i<n; i++ )
         {  if  ( (w = buff[i]) != 0        // not run out
                   &&  (w&0x7F) != 0x7F )   // and not delete
            {  w = (w&0x60)/2 + (w&0xF);
               if  ( w == 6 )               // case shift
                  tab = stab;
               else if  ( w == 7 )          // case normal
                  tab = ntab;
               else
                  buff[m++] = tab[w];
            }
         // printf("%02X => %d\n", buff[i]&255, w);
         }
         write(dvo, buff, m);
      }
   }

   else if  ( *mode == 'o' )      /* show KDF9 tapes as numbers */
   {  int dvi = open(argv[2], O_RDONLY + O_BINARY);
      int n, i, m, w;
      long ww;
      n = read(dvi, buff, BUFF_SIZE);
      m = 0;  ww = 0;
      if  ( n > 0  &&  n < BUFF_SIZE )      // read all of file OK
      {  for  ( i = 0; i<n; i++ )
         {  if  ( (w = buff[i]) != 0        // not run out
                   &&  (w&0xFF) != 0xFF )   // and not delete
            {  w = (w&0x60)/2 + (w&0xF);
               buff[m++] = w;
            }
         }

         i = -1;
         while ( (n=8*(++i))<m )
         {  printf("%5o (%4d):", i, i);
            printf(" %02o %02o %02o %02o %02o %02o %02o %02o :",
                      buff[n], buff[n+1], buff[n+2], buff[n+3], buff[n+4], buff[n+5], buff[n+6], buff[n+7]);
            w = (((buff[n]<<6) + buff[n+1]<<6) + buff[n+2]<<6) + buff[n+3];
            printf(" %03o %03o %03o", w>>16, (w>>8)&255, w&255);
            n += 4;
            w = (((buff[n]<<6) + buff[n+1]<<6) + buff[n+2]<<6) + buff[n+3];
            printf(" %03o %03o %03o\n", w>>16, (w>>8)&255, w&255);
         }

      }
   }

   else if  ( *mode == 'n' )      /* show numeric values of EDSAC 2 characters */
   {  int dvi = open(argv[2], O_RDONLY + O_BINARY);
      int n, i, m, w;
      n = read(dvi, buff, BUFF_SIZE);
      if  ( n > 0  &&  n < BUFF_SIZE )      // read all of file OK
      {  for  ( i = 0; i<n; i++ )
         {  if  ( (w = buff[i]&0x1F) == 2 ) // carriage return
               printf(" -");
            else if  ( w == 8 )             // line feed
               printf("\n");
            else
               printf(" %d", w);
         }
         printf("\n");
      }
   }

   else if  ( *mode == 'N' )      /* rebuild the raw tape from a numbers - 5-hole */
   {  int dvi = open(argv[2], O_RDONLY + O_BINARY);
      int dvo = open(argv[3], O_WRONLY + O_TRUNC + O_CREAT + O_BINARY);
      int n, i, m, w, ww;
      n = read(dvi, buff, BUFF_SIZE);
      m = 0;
      if  ( n > 0  &&  n < BUFF_SIZE )      // read all of file OK
      {  for  ( i = 0; i<n; i++ )
         {  if  ( (w = buff[i]) == '-' )    // carriage return
               buff[m++] = 2;
            else if  ( w == '\n' )          // line feed
               buff[m++] = 8;
            else if  ( w >= '0'  &&  w <= '9' )
            {  w -= '0';                    // convert to binary value of digit
               if  ( (ww = buff[i+1]) >= '0'  &&  ww <= '9' )
               {  i ++;
                  w = w*10 + ww - '0';      // convert 2-digit number
               }
               buff[m++] = w;
            }
         }
         write(dvo, buff, m);
      }
   }

   else if  ( *mode == 'e' )      /* show EDSAC 2 tapes as characters */
   {  int dvi = open(argv[2], O_RDONLY + O_BINARY);
      int dvo = open(argv[3], O_WRONLY + O_TRUNC + O_CREAT + O_BINARY);
      int n, i, m, w;
      char *tab;
      tab = ftab;
   // printf("%c %c %c %c %c\n", ntab[32], ntab[33], ntab[34], ntab[35], ntab[36]);
   // printf("%c %c %c %c %c\n", stab[32], stab[33], stab[34], stab[35], stab[36]);
   // printf("%c %c %c %c %c\n", tab[32], tab[33], tab[34], tab[35], tab[36]);
      n = read(dvi, buff, BUFF_SIZE);
      m = 0;
      if  ( n > 0  &&  n < BUFF_SIZE )      // read all of file OK
      {  for  ( i = 0; i<n; i++ )
         {  if  ( (w = buff[i]&0x1F) != 0 ) // not run out
            {  if  ( w == 31 )              // figure shift
                  tab = ftab;
               else if  ( w == 27 )         // letter shift
                  tab = ltab;
               else
                  buff[m++] = tab[w];
            }
         }
         write(dvo, buff, m);
      }
      printf("Ending code = %d/%d\n", n, m);
   }

   else if  ( *mode == 'i' )      /* show ISO tapes as characters */
   {  int dvi = open(argv[2], O_RDONLY + O_BINARY);
      int dvo = open(argv[3], O_WRONLY + O_TRUNC + O_CREAT + O_BINARY);
      int n, i, m, w;
      char *tab;
      tab = ntab;
      n = read(dvi, buff, BUFF_SIZE);
      m = 0;
      if  ( n > 0  &&  n < BUFF_SIZE )      // read all of file OK
      {  for  ( i = 0; i<n; i++ )
            if  ( (w = buff[i]&127) != 0    // not run out
                    &&  w != 127 )          // not delete
               buff[m++] = w;

         write(dvo, buff, m);
      }
      printf("Ending code = %d/%d\n", n, m);
   }

   else if  ( *mode == 'b' )      /* interpret KDF9 binary paper tape program */
   {  int dvi = open(argv[2], O_RDONLY + O_BINARY);
      int dvo = open(argv[3], O_WRONLY + O_TRUNC + O_CREAT + O_BINARY);
      int n, i, m, w, ww;
      unsigned char opb[4];              /* output buffer */

      n = read(dvi, buff, BUFF_SIZE);
      m = 0;
      if  ( n > 0  &&  n < BUFF_SIZE )      // read all of file OK
      {  i = 0;
         if  ( buff[0] != 0x17  ||  buff[1] != 0x12
               || buff[2] != 0x60  ||  buff[3] != 0x12 )
            printf("This is probably not a binary paper tape program %02X %02X %02X %02X\n",
                     buff[0], buff[1], buff[2], buff[3]);
         else
         {  while  ( (w = buff[i++])!=0x7D )  // process the A-block
            {  w = (w&0x60)/2 + (w&0xF);
               buff[m++] = ntab[w];
            }
            buff[m] = 0;                      // ensure string is terminated
            printf("A-block\n%s\n", buff);

            m = 0;

            while  ( i<n )
            {  w = buff[i++];
               w = (w&0x60)/2 + (w&0xF);
               ww = buff[i++];
               ww = (ww&0x60)/2 + (ww&0xF);
               buff[m++] = w<<2 | ww>>4;
               w = buff[i++];
               w = (w&0x60)/2 + (w&0xF);
               buff[m++] = ww<<4 | w>>2;
               ww = buff[i++];
               ww = (ww&0x60)/2 + (ww&0xF);
               buff[m++] = w<<6 | ww;
            }
            write(dvo, buff, m);
            if  ( buff[44] != 0  ||  buff[45] != 8 )
               printf("Beware, binary program starts at word %d\n", buff[44]<<8 | buff[45] );
         }
      }
      printf("Ending code = %d/%d\n", n, m);
   }

   else if  ( *mode == 'x' )      /* examine ignoring initial and final nulls */
   {  int dvi = open(argv[2], O_RDONLY + O_BINARY);
      int dv2 = open(argv[3], O_RDONLY + O_BINARY);
      int n, i, m, w, d1, d2;
      char chs[30] = "                              ";
      n = read(dvi, buff, BUFF_SIZE);
      m = read(dv2, buff2, BUFF_SIZE);
      if  ( n > 0  &&  n < BUFF_SIZE )      // read all of file1 OK
      if  ( m > 0  &&  m < BUFF_SIZE )      // read all of file2 OK
      {  d1 = 0;
         d2 = 0;
         while  ( buff[++d1] == 0 ) ;
         while  ( buff2[++d2] == 0 ) ;

         printf("n = %d, d1 = %d :: m = %d, d2 = %d\n", n, d1, m, d2);

         while  ( d1 < n  &&  d2 < m  &&  buff[d1++] == buff2[d2++] ) ;
         if  ( d1 < n  &&  d2 < m )
         {  d1 --;   d2 --;
            printf("Mismatch d1 = %d, d2 = %d\n", d1, d2);
            chs[25] = 0;
            for  ( i = -1; i<20; i++ )
            {  showchar(buff[d1+i], chs+2);
               showchar(buff[d2+i], chs+15);
               printf("%s\n", chs);
            }
         }
      }
      printf("Ending code = %d/%d\n", n, m);
   }

   else
      printf("Mode %s not recognised\n", mode);

}