/*
    A program to convert IBM mainframe EBDIC text files to ASCII
    
          Andrew D. Todd
          
          Aug 10, 1998
   ------------------------------------------------------------
     syntax: EBDTOASC src dst
              
              where src, dst are filespecs
  ----------------------------------------------------------------
             environment: MS-DOS, using MIX Power C compiler
             (superset of Microsoft C, Borland Turbo C), however,
             should be extremely portable.
  -----------------------------------------------------------------
             This program is in the public domain, and may be 
             used for any purpose whatsover, without permission 
             or notification, but is offered "as-is" without any 
             warrentee, express or implied.
  -----------------------------------------------------------------

                                   Andrew D. Todd
                                   1249 Pineview Dr., Apt 4
                                   Morgantown, WV 26505

                                   U46A8@WVNVM.WVNET.EDU

*/
#include <stdio.h>
#include <io.h>
#include <fcntl.h>
#include <sys\types.h>
#include <sys\stat.h>
main(int argc, char *argv[])
{
  int space_cnt, status, f_in, f_out;
  char c, c1, c2, c1c, c2c;
  char *hex_rep = "\r\n[xx]\r\n";
  if( argc < 3 )
  {
    printf(" \nBoth Source and Destination Files Needed\n");
    _exit(3);
  }
  f_in = open(argv[1], O_RDONLY|O_BINARY);
  if(f_in == -1) 
  {
    printf(" \n%s Does Not Exist\n", argv[1]);
    _exit(4);
  }
  f_out = open(argv[2], O_WRONLY|O_CREAT|O_EXCL|O_BINARY, S_IREAD|S_IWRITE);
  if( f_out == -1) 
  {
    printf(" \nDestination File  %s Invalid\n", argv[2]);
    _exit(5);
  }
  for(;;)            /* Do for the whole file */
  {
    status = read(f_in, &c, 1);
    if(status != 1) break;
    else if( conversion_available(c, f_out) ); /*puts that out*/
    else 
    {
     c2=c%16; 
     c1=(c-c2)/16; 
     if(c1 <= 9) c1c = c1 + '0';
           else c1c = c1 + 'A'-10;
     if(c2 <= 9) c2c = c2 + '0';
           else c2c = c2 + 'A'-10;
     hex_rep[3] = c1c;
     hex_rep[4] =c2c;
     write(f_out, hex_rep, 8);
    }
  }
  close(f_in);
  close(f_out);
  _exit(0);
}
/*----------------------------------------------------*/
conversion_available(char c, int f_out)
{
   char c_o;
   int return_code;
   return_code = 1;
   if( 
       test_range(c, &c_o, '\x81', '\x89', 'a') 
     ||
       test_range(c, &c_o, '\x91', '\x99', 'j') 
     ||
       test_range(c, &c_o, '\xa2', '\xa9', 's') 
     ||
       test_range(c, &c_o, '\xc1', '\xc9', 'A') 
     ||
       test_range(c, &c_o, '\xd1', '\xd9', 'J') 
     ||
       test_range(c, &c_o, '\xe2', '\xe9', 'S') 
     ||
       test_range(c, &c_o, '\xf0', '\xf9', '0') 
     )
      write(f_out, &c_o, 1);
   else if( 
            test_special_chars(c, &c_o) 
          )
      write(f_out, &c_o, 1);
   else return_code = 0;
   /*always*/ 
   return(return_code);
}
/*-------------------------------------------------*/
test_special_chars(char c, char *c_o)
{
   int c_found;
   c_found = 0;
   switch(c)
   {
      case '\x40':  *c_o = ' '; c_found = 1; break; /*cent*/

      case '\x4a':  *c_o = 'c'; c_found = 1; break; /*cent*/
      case '\x4b':  *c_o = '.'; c_found = 1; break;
      case '\x4c':  *c_o = '<'; c_found = 1; break;
      case '\x4d':  *c_o = '('; c_found = 1; break;
      case '\x4e':  *c_o = '+'; c_found = 1; break;
      case '\x4f':  *c_o = '|'; c_found = 1; break;
      case '\x50':  *c_o = '&'; c_found = 1; break;
      
      case '\x5a':  *c_o = '!'; c_found = 1; break;
      case '\x5b':  *c_o = '$'; c_found = 1; break;
      case '\x5c':  *c_o = '*'; c_found = 1; break;
      case '\x5d':  *c_o = ')'; c_found = 1; break;
      case '\x5e':  *c_o = ';'; c_found = 1; break;
      case '\x5f':  *c_o = '~'; c_found = 1; break; /*EBDIC not mark*/
      case '\x60':  *c_o = '-'; c_found = 1; break;
      case '\x61':  *c_o = '/'; c_found = 1; break;
      
      case '\x6a':  *c_o = '|'; c_found = 1; break;
      case '\x6b':  *c_o = ','; c_found = 1; break;
      case '\x6c':  *c_o = '%'; c_found = 1; break;
      case '\x6d':  *c_o = '_'; c_found = 1; break;
      case '\x6e':  *c_o = '>'; c_found = 1; break;
      case '\x6f':  *c_o = '?'; c_found = 1; break;
      
      case '\x7a':  *c_o = ':'; c_found = 1; break;
      case '\x7b':  *c_o = '#'; c_found = 1; break;
      case '\x7c':  *c_o = '@'; c_found = 1; break;
      case '\x7d':  *c_o = '\x27'; c_found = 1; break; /*apostrophe*/
      case '\x7e':  *c_o = '='; c_found = 1; break;
      case '\x7f':  *c_o = '\x22'; c_found = 1; break; /*quote mark*/
      
      case '\xa1':  *c_o = '~'; c_found = 1; break;

      case '\xad':  *c_o = '['; c_found = 1; break;
      case '\xbd':  *c_o = ']'; c_found = 1; break;
      
      case '\xc0':  *c_o = '{'; c_found = 1; break;
      
      case '\xcc':  *c_o = 'S'; c_found = 1; break; /* integral */

      case '\xce':  *c_o = 'Y'; c_found = 1; break; /*what?*/
      
      case '\xd0':  *c_o = '}'; c_found = 1; break;
      
      case '\xe0':  *c_o = '\\'; c_found = 1; break;
      
      case '\xec':  *c_o = 'h'; c_found = 1; break; /*what ?*/
      
      case '\xfa':  *c_o = '|'; c_found = 1; break;
      
      default: c_found = 0;
   }
   return(c_found);
}
/*----------------------------------------------------------------*/   
test_range(
             char c, 
             char *c_o, 
             char l_bound, 
             char u_bound, 
             char start_trans
          )
{
   if(
        ( c >= l_bound)
        &&
        ( c <= u_bound) 
       )
   {  
      *c_o= c + start_trans - l_bound;
      return(1);
   }
   else return(0);
}