/*
 * bin2txt input [remote_name] > output 
 *
 * Encode a binary file as text so it can be mailed to a remote system. 
 * File integrity check is limited to a single CRC-16 check of the file. 
 *
 *   input       - The input binary file.
 *
 *   remote_name - The optional name of the remote binary file.
 *                 (If this is not given, the remote name = input name)
 * 
 *   output      - The output is to stdio and can be redirected as shown 
 *                 to the resulting text file.
 */

# include <stdlib.h>
# include <stdio.h>
     
unsigned short CRC = 0x0000;  /* CRC-16 accumulator */
     
/* crctab calculated by Mark G. Mendel, Network Systems Corporation */ 

static unsigned short crctab[256] = {
    0x0000,  0x1021,  0x2042,  0x3063,  0x4084,  0x50a5,  0x60c6,  0x70e7, 
    0x8108,  0x9129,  0xa14a,  0xb16b,  0xc18c,  0xd1ad,  0xe1ce,  0xf1ef, 
    0x1231,  0x0210,  0x3273,  0x2252,  0x52b5,  0x4294,  0x72f7,  0x62d6, 
    0x9339,  0x8318,  0xb37b,  0xa35a,  0xd3bd,  0xc39c,  0xf3ff,  0xe3de, 
    0x2462,  0x3443,  0x0420,  0x1401,  0x64e6,  0x74c7,  0x44a4,  0x5485, 
    0xa56a,  0xb54b,  0x8528,  0x9509,  0xe5ee,  0xf5cf,  0xc5ac,  0xd58d, 
    0x3653,  0x2672,  0x1611,  0x0630,  0x76d7,  0x66f6,  0x5695,  0x46b4, 
    0xb75b,  0xa77a,  0x9719,  0x8738,  0xf7df,  0xe7fe,  0xd79d,  0xc7bc, 
    0x48c4,  0x58e5,  0x6886,  0x78a7,  0x0840,  0x1861,  0x2802,  0x3823, 
    0xc9cc,  0xd9ed,  0xe98e,  0xf9af,  0x8948,  0x9969,  0xa90a,  0xb92b, 
    0x5af5,  0x4ad4,  0x7ab7,  0x6a96,  0x1a71,  0x0a50,  0x3a33,  0x2a12, 
    0xdbfd,  0xcbdc,  0xfbbf,  0xeb9e,  0x9b79,  0x8b58,  0xbb3b,  0xab1a, 
    0x6ca6,  0x7c87,  0x4ce4,  0x5cc5,  0x2c22,  0x3c03,  0x0c60,  0x1c41, 
    0xedae,  0xfd8f,  0xcdec,  0xddcd,  0xad2a,  0xbd0b,  0x8d68,  0x9d49, 
    0x7e97,  0x6eb6,  0x5ed5,  0x4ef4,  0x3e13,  0x2e32,  0x1e51,  0x0e70, 
    0xff9f,  0xefbe,  0xdfdd,  0xcffc,  0xbf1b,  0xaf3a,  0x9f59,  0x8f78, 
    0x9188,  0x81a9,  0xb1ca,  0xa1eb,  0xd10c,  0xc12d,  0xf14e,  0xe16f, 
    0x1080,  0x00a1,  0x30c2,  0x20e3,  0x5004,  0x4025,  0x7046,  0x6067, 
    0x83b9,  0x9398,  0xa3fb,  0xb3da,  0xc33d,  0xd31c,  0xe37f,  0xf35e, 
    0x02b1,  0x1290,  0x22f3,  0x32d2,  0x4235,  0x5214,  0x6277,  0x7256, 
    0xb5ea,  0xa5cb,  0x95a8,  0x8589,  0xf56e,  0xe54f,  0xd52c,  0xc50d, 
    0x34e2,  0x24c3,  0x14a0,  0x0481,  0x7466,  0x6447,  0x5424,  0x4405, 
    0xa7db,  0xb7fa,  0x8799,  0x97b8,  0xe75f,  0xf77e,  0xc71d,  0xd73c, 
    0x26d3,  0x36f2,  0x0691,  0x16b0,  0x6657,  0x7676,  0x4615,  0x5634, 
    0xd94c,  0xc96d,  0xf90e,  0xe92f,  0x99c8,  0x89e9,  0xb98a,  0xa9ab, 
    0x5844,  0x4865,  0x7806,  0x6827,  0x18c0,  0x08e1,  0x3882,  0x28a3, 
    0xcb7d,  0xdb5c,  0xeb3f,  0xfb1e,  0x8bf9,  0x9bd8,  0xabbb,  0xbb9a, 
    0x4a75,  0x5a54,  0x6a37,  0x7a16,  0x0af1,  0x1ad0,  0x2ab3,  0x3a92, 
    0xfd2e,  0xed0f,  0xdd6c,  0xcd4d,  0xbdaa,  0xad8b,  0x9de8,  0x8dc9, 
    0x7c26,  0x6c07,  0x5c64,  0x4c45,  0x3ca2,  0x2c83,  0x1ce0,  0x0cc1, 
    0xef1f,  0xff3e,  0xcf5d,  0xdf7c,  0xaf9b,  0xbfba,  0x8fd9,  0x9ff8, 
    0x6e17,  0x7e36,  0x4e55,  0x5e74,  0x2e93,  0x3eb2,  0x0ed1,  0x1ef0
};
     
/*
 * updcrc macro derived from article Copyright (C) 1986 Stephen Satchell. 
 *  NOTE: First argument must be in range 0 to 255.
 *        Second argument is referenced twice. 
 *
 * Programmers may incorporate any or all code into their programs, 
 * giving proper credit within the source. Publication of the
 * source routines is permitted so long as proper credit is given 
 * to Stephen Satchell, Satchell Evaluations and Chuck Forsberg, 
 * Omen Technology.
 */
     
#define updcrc(cp, crc) ( crctab[((crc>>8)&0x0FF)]^(crc<<8)^(cp&0x0FF) ) 

int main ( int argc, char **argv );
char ENC(char ch);
void encode ( FILE *in, FILE *out );
void outdec ( char *p, FILE *f );
int fr ( FILE *fd, char *buf, int cnt );

/******************************************************************************/

int main ( int argc, char **argv )

/******************************************************************************/
{

        FILE *in;
        char *remote_file;
        char *temp_file;
     
        /* Default to "Usage" mode if incorrect arguments */

        if (argc < 2 || argc > 3)
         {
          printf("Usage: bin2txt infile [remote_name] >text_file\n"); 
          exit ( 2 );
         }
     
        /* 1st argument is input file */

        if ((in = fopen(argv[1], "rb")) == NULL)

         {
          printf("Can't open input file: %s\n", argv[1]); 
          exit ( 1 );
         }

        /* 2nd argument is optional */
        if (argc > 2) argv++; /* This points to second argument if it */
                              /* exists. The remote file name is then */ 
                              /* always argv[1].                      */
     
        for (temp_file=argv[1],remote_file=temp_file;
          *temp_file; temp_file++)
             if (*temp_file == ':' ||
                 *temp_file == '\\' ||
                 *temp_file == '/' ||
                 *temp_file == ']')
               remote_file = temp_file + 1;
     
        printf("...begin... 777 %s\n", remote_file);
     
        encode(in, stdout);
     
        printf("end\n");

  return 0;
}
     
/*
 * Encode characters (avoiding ebcdic<->ascii problem chars and spaces) 
 */
/******************************************************************************/

char ENC(char ch)

/******************************************************************************/
{
 /* The basic 1 character encoding function makes a printable char */ 
 /* The input is a 6 bit char (00-3F). The output is input+0x20    */ 
 ch = (ch & 0x03F) + ' ';
     
 /* avoid the following chars by converting to unused lower case chars */ 
 switch (ch)
  {
   case ' '  : ch = 'm';
               break;
   case '['  : ch = 'd';
               break;
   case '\\' : ch = 'e';
               break;
   case ']'  : ch = 'f';
               break;
   case '^'  : ch = 'g';
               break;
   case '\'' : ch = 'h';
               break;
  }
 return(ch);
}
     
     
/*
 * copy from in to out, encoding as you go along. 
 */
/******************************************************************************/

void encode ( FILE *in, FILE *out )

/******************************************************************************/
{
    char buf[80];
    int i, n;
     
    for (;;)
     {
      /* 1 (up to) 45 characters per line */ 
      n = fr(in, buf, 45);
      putc(ENC(n), out);
      for (i=0; i<n; i++) CRC = updcrc(buf[i], CRC);
     
      for (i=0; i<n; i += 3) outdec(&buf[i], out);
     
      putc('\n', out);
      if (n <= 0) break;
     }
     
    fprintf(out,"CRC= %04X\n",CRC);
     
}
     

/******************************************************************************/
 
void outdec ( char *p, FILE *f )

/******************************************************************************/
/*
  output one group of 3 bytes, pointed at by p, on file f. 
*/
{
    int c1, c2, c3, c4;
     
    c1 = *p >> 2;
    c2 = ( (*p << 4) & 0x30 ) | ( (p[1] >> 4) & 0x0F ); 
    c3 = ( (p[1] << 2) & 0x3C ) | ( (p[2] >> 6) & 0x03 ); 
    c4 = p[2] & 0x3F;
    putc(ENC(c1), f);
    putc(ENC(c2), f);
    putc(ENC(c3), f);
    putc(ENC(c4), f);

  return;
}
     
     
/* fr: like read but stdio */
/******************************************************************************/

int fr ( FILE *fd, char *buf, int cnt )

/******************************************************************************/
{
    int c, i;
     
    for (i=0; i<cnt; i++)
     {

      c = getc(fd);
      if (feof(fd)) return(i);

      buf[i] = c;
     }
    return (cnt);
}