/* lpf.lj4m.c -- Michael A. Covington, 1993 July 6
   Pre-spooler filter for LaserJet 4M.
   Install with the "if=" (NOT "of=") option in /etc/printcap.

   Examines first 2 bytes of each file to classify it as
   HP printer code, PostScript, or ASCII.

   Then does the following:
     - Transmits HP printer code transparently.
         (Must begin with Esc E.)
     - Transmits PostScript code transparently, adding Ctrl-D at the end.
     - Transmits ASCII code thus:
       + Adds printer setup (font selection, etc.) at beginning;
       + Adds a blank at the beginning of each line
	  (so the 4M won't mistake Prolog programs for PostScript);
       + Breaks lines more than 80 characters long;
       + Aborts if the file contains unprintable bytes.

   Install with the "if=" (NOT "of=") option in printcap.

   Print jobs are logged in /var/adm/lpd-errs.

   BUG: Does not produce correct results on jobs shorter than 2 bytes.
   But who would print such a file anyhow?  (Famous last words...)

   This program can be tested under other operating systems because
   the UNIX-specific parts are subject to "#ifdef UNIX".
 */

#define UNIX 1

#ifdef UNIX
#include <syslog.h>
#endif

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

#define CTRLD      "\004"

#define SPACES     " "        /* prepended to every ASCII line */
#define LINELENGTH 80

/* HP LaserJet control sequences */

#define RESET      "\033E"
#define LF_TO_CRLF "\033&k2G"
#define LMARGIN    "\033&a11L"
#define PORTRAIT   "\033&l0O"
#define ASCII      "\033(8U"
#define FONT       "\033(s0p(s12h(s4099T"
#define LOWERTRAY  "\033&l1H"


/* Globals */

int        c1, c2;
long int   bytes = 1;
char       username[64] = "";

#define PRINTABLE(c)  (Printable[(unsigned char)c])

char       Printable[256] =
       /* Table of which ASCII codes are printable characters */
       { 0,0,0,0,1,0,0,1,1,1,1,0,1,1,0,0,   /* NUL to ^O  */
	 0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,   /* ^P to 31   */
         1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,   /* 32 to 47   */
	 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,   /* 48 to 63   */
	 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,   /* 64 to 79   */
	 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,   /* 80 to 95   */
	 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,   /* 96 to 112  */
	 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,   /* 113 to 127  */
	 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,   /* 128 to 143 */
	 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,   /* 144 to 159 */
	 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,   /* 160 to 175 */
	 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,   /* 176 to 191 */
	 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,   /* 192 to 207 */
	 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,   /* 208 to 223 */
	 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,   /* 224 to 239 */
	 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1 }; /* 240 to 255 */
                              /* -1 (eof) maps onto 255 */

/************ FUNCTIONS *************/

void parse_user_name(int argc, char* argv[]){
  /*
   *   Obtain user name if it was passed to the program
   */
  if (argc>8) {
   strcat(username,argv[5]); 
   strcat(username,"@");
   strcat(username,argv[7]);   
  }
}

void process_postscript(){
  /*
   *   Transmit PostScript file transparently to stdout
   */
  #ifdef DEBUG
  fprintf(stderr,"lpf.lj4m: %s: File treated as PostScript\n",username);
  #endif
  putc(c1,stdout);
  while(!feof(stdin)) { bytes++;  putc(c2,stdout); c2 = getc(stdin); }
  /*
   *   Add newline and Ctrl-D at end
   */
  fputs("\n"CTRLD,stdout);
  /*
   *   Report results
   */
  #ifdef UNIX
  syslog(LOG_DEBUG,"%s, PostScript file, %d bytes",username,bytes);
  #endif
  #ifdef DEBUG
  fprintf("lpf.lj4m: %s: End of PostScript job\n",username);
  #endif
}

void process_hp(){
  /*
   *   Transmit Hewlett-Packard code transparently, then reset printer
   */
  #ifdef DEBUG
  fprintf(stderr,"lpf.lj4m: %s: File treated as HP LaserJet code\n",username);
  #endif
  putc(c1,stdout);
  while(!feof(stdin)) { bytes++; putc(c2,stdout); c2 = getc(stdin); }
  /*
   *   Add Reset at end
   */
  fputs(RESET,stdout);
  /*
   *   Report results
   */
  #ifdef DEBUG
  fprintf(stderr,"lpf.lj4m: %s: End of LaserJet job\n",username);
  #endif
  #ifdef UNIX
  syslog(LOG_DEBUG,"%s, LaserJet file, %d bytes",username,bytes);
  #endif
}


void process_ascii(){
  int  charcount = 0, ok_to_print;
  int  k = 0;
  /*
   *   Initialization
   */
  #ifdef DEBUG
  fprintf(stderr,"lpf.lj4m: %s: File treated as ASCII text\n",username);
  #endif
  /*
   *   Set up printer
   */
  fputs(RESET,stdout);       
  fputs(LF_TO_CRLF,stdout);
  fputs(FONT,stdout);
  fputs(LMARGIN,stdout);
  /*
   *   Transmit file, prepending ' ' to each line,
   *   and breaking lines that exceed 80 characters    <-- to do
   *   and bailing out if unprintable bytes are found
   */
  ok_to_print = PRINTABLE(c1) && PRINTABLE(c2);
  fputs(SPACES,stdout);
  if (ok_to_print) putc(c1,stdout);
  while(ok_to_print && !feof(stdin)) {

    bytes++;

    if ((charcount >= LINELENGTH) && (c2 != '\n')) {
       fputs("\n"SPACES,stdout);     /* start new line, indented, if needed */
       charcount = 0;
    }

    if ((c2 != 4) && (c2 != 26)) {   /* whatever the character */
       putc(c2,stdout);              /* print if not ^D, ^Z */
       charcount++;
    }

    if (c2 == '\n') {                /* if end of line */
       fputs(SPACES,stdout);         /* indent next line */
       charcount = 0;
    }


    c2 = getc(stdin);
    ok_to_print = PRINTABLE(c2);
  }
  /*
   *   If a bad byte was found, print messages:
   */
  if(!ok_to_print){
    /*
     *   Set up printer again, because it may have been disrupted
     */
    fputs("\n",stdout);
    fputs(RESET,stdout);       
    fputs(LF_TO_CRLF,stdout);
    fputs(FONT,stdout);
    fputs(LMARGIN,stdout);
    /*
     * Message in the printout itself
     */
    fprintf(stdout," ERROR\n\n Print job for %s\n\n",username);
    fprintf(stdout," Unprintable character, code %d, location %d\n\n",c2,bytes);
    fprintf(stdout," The print filter assumed that this file was ASCII text,\n");
    fprintf(stdout," but found an unprintable character in it.\n\n");
    fprintf(stdout," Here is a portion of the file:");

    /*
     * Partial dump of file
     */
      while((k<80*30) && (!feof(stdin))) {
        if (k % 80 == 0) fputs("\n"SPACES,stdout);
        if ((c2 >= 32) && (c2 <= 126)) 
           putc(c2,stdout); 
        else 
           putc('.',stdout);
        c2 = getc(stdin);
        k++;
      }

    /*
     * Message to console 
     */
    fprintf(stderr,"lpf.lj4m: %s: tried to print an unprintable file\n",username);
    /*
     * Message to system logs
     */
    #ifdef UNIX
    syslog(LOG_ERR,"lpf.lj4m: %s: tried to print an unprintable file\n",username);
    #endif
  }
  /*
   *   Reset printer at end
   */
  fprintf(stdout,"%s",RESET);
  /*
   *   Report results
   */
  #ifdef DEBUG
  fprintf(stderr,"lpf.lj4m: %s: End of ASCII job\n",username);
  #endif 
  #ifdef UNIX
  syslog(LOG_DEBUG,"%s, ASCII file, %d bytes",username,bytes);
  #endif
}






/************** MAIN ****************/

main(int argc, char* argv[]){

/*
 *   Initialization
 */

  parse_user_name(argc,argv);     

  #ifdef UNIX
  openlog("LaserJet",0,LOG_LPR);
  #endif

/*
 *   Examine first 2 bytes and determine type of file
 */

  c1 = getc(stdin);
  c2 = getc(stdin);

  if ( (c1 == '%') && (c2 == '!') )      process_postscript();
  else if ( (c1 == 27) && (c2 == 'E') )  process_hp();
  else                                   process_ascii();

  #ifdef UNIX
  closelog();
  #endif
  return(0);   /* IMPORTANT! UNIX insists on this.*/
}