fix problems with form feeds (sorta a kludge)

[unix-history] / usr / src / usr.sbin / lpr / filters / lpf.c

/*      lpf.c   4.3     81/06/02        */
/*
* lpf -- Line printer filter: handles underlines for those printers/
*        device drivers that won't
*/

#include <stdio.h>
#include <signal.h>

#define LINELN  132

char    linebuf[LINELN+2];
int     ov;
int     ff;
char    ovbuf[LINELN];

main()
{
       extern char _sobuf[BUFSIZ];

       setbuf(stdout, _sobuf);
       while (getline())
               putline();
       fflush(stdout);
       if (ferror(stdout))
               exit(1);
       exit(0);
}

getline()
{
       register int col, maxcol, c;

       ov = 0;
       for (col=0; col<LINELN; col++) {
               linebuf[col] = ' ';
               ovbuf[col] = 0;
       }
       col = 0;
       maxcol = 0;
       for (;;) switch (c = getchar()) {

       case EOF:
               return(0);

       default:
               if (c>=' ') {
                       if (col < LINELN) {
                               if (linebuf[col]=='_') {
                                       ov++;
                                       ovbuf[col] = '_';
                               }
                               linebuf[col++] = c;
                               if (col > maxcol)
                                       maxcol = col;
                       }
               }
               continue;

       case ' ':
               col++;
               continue;

       case '\t':
               col = (col|07) + 1;
               if (col>maxcol)
                       maxcol = col;
               continue;

       case '\r':
               col = 0;
               continue;

       case '_':
               if (col>=LINELN) {
                       col++;
                       continue;
               }
               if (linebuf[col]!=' ') {
                       ovbuf[col] = '_';
                       ov++;
               } else
                       linebuf[col] = c;
               col++;
               if (col>maxcol)
                       maxcol = col;
               continue;

       case '\f':
               ff = 1;         /* force form feed */
       case '\n':
               if (maxcol>=LINELN)
                       maxcol = LINELN;
               linebuf[maxcol] = 0;
               return(1);

       case '\b':
               if (col>0)
                       col--;
               continue;
       }
}

putline()
{
       register char *lp, *ep;
       register int c;

       lp = linebuf;
       while (c = *lp++)
               output(c);
       if (ov) {
               putchar('\r');
               for (ep= &ovbuf[LINELN-1]; *ep == 0; ep--)
                       continue;
               for (lp=ovbuf; lp <= ep; lp++)
                       output(*lp ? *lp : ' ');
       }
       putchar('\n');
       if (ff) {
               ff = 0;
               putchar('\f');
       }
       if (ferror(stdout))
               exit(1);
}

output(c)
register char c;
{

       if (c == -1)
               return;
       c &= 0177;
       if (c == 0177)
               putchar('^'), c = '?';
       if (c == 033)
               c = '$';
       if (c < ' ') switch (c) {

       case '\n':
               break;

       case '\f':
       case '\b':
       case '\t':
       case '\r':
               break;

       default:
               putchar('^');
               c |= 0100;
       }
       putchar(c);
}