v03i044: backspace filter

[chad at anasaz.UUCP]

comp.sources.misc: Volume 3, Issue 44
Submitted-By: "A. Nonymous" <chad at anasaz.UUCP>
Archive-Name: nobs

[Why not "col -b"?  ++bsa]

This is a filter that has probably been written a thousand times, but
here is another version.  It is used to clean up nroff output
generated for the default TTY37 terminal for printing on a printer
that cannot backspace (or one that beats itself silly when it does):
    nroff -man foo.1 | nobs > foo.man
It has been tested on SysVr2, but should work anywhere.
----(cut)--------(cut)--------(cut)--------(cut)--------(cut)----
#! /bin/sh
# This is a shell archive.  Remove anything before this line, then unpack
# it by saving it into a file and typing "sh file".  To overwrite existing
# files, type "sh file -c".  You can also feed this as standard input via
# unshar, or by typing "sh <file", e.g..  If this archive is complete, you
# will see the following message at the end:
#		"End of shell archive."
# Contents:  Makefile nobs.c
# Wrapped by chad at anasaz on Tue Jun  7 20:13:35 1988
PATH=/bin:/usr/bin:/usr/ucb ; export PATH
if test -f 'Makefile' -a "${1}" != "-c" ; then 
  echo shar: Will not clobber existing file \"'Makefile'\"
else
echo shar: Extracting \"'Makefile'\" \(238 characters\)
sed "s/^X//" >'Makefile' <<'END_OF_FILE'
X# %M% for nobs
X
XBINDIR = /usr/local/bin
XTARGET = nobs
X
X$(TARGET): nobs.c
X	$(CC) $(CFLAGS) -o $(TARGET) nobs.c
X
Xinstall: nobs
X	strip nobs
X	@-rm $(BINDIR)/$(TARGET)
X	ln $(TARGET) $(BINDIR)
X	touch install
X
XLint:	nobs.c
X	lint -p nobs.c >Lint
END_OF_FILE
if test 238 -ne `wc -c <'Makefile'`; then
    echo shar: \"'Makefile'\" unpacked with wrong size!
fi
# end of 'Makefile'
fi
if test -f 'nobs.c' -a "${1}" != "-c" ; then 
  echo shar: Will not clobber existing file \"'nobs.c'\"
else
echo shar: Extracting \"'nobs.c'\" \(2474 characters\)
sed "s/^X//" >'nobs.c' <<'END_OF_FILE'
X/* nobs.c - Simple backspace filter - 1.1 */
X
X/*
X** This program will take lines containing overstrike pragmas of
X** the form <char><bs><char> and convert them to individual lines of
X** output with a return but no line feed between them.
X** Useful in filtering nroff output to line printers that cannot
X** back space (or on which back spaces are expensive).
X*/
X
X/*
X** Author:
X**   Chad R. Larson			This program is placed in the
X**   DCF, Inc.				Public Domain.  You may do with
X**   14623 North 49th Place		it as you please.
X**   Scottsdale, AZ 85254
X*/
X
X#include <stdio.h>
X
X#define	LINESIZE	512		/* maximum line length */
X#define MAXOVER		8		/* maximum number of overstrikes */
X
X/* forward references */
Xvoid exit();
Xchar *memset();
X
Xstatic char input[LINESIZE];		/* input line buffer */
Xstatic char output[MAXOVER][LINESIZE];	/* output line buffers */
X
Xvoid main()
X{
X    int		line;		/* output buffer array index */
X    int		in_dex;		/* offset into input buffer */
X    int		out_dex;	/* offset into output buffer */
X    int		line_count;	/* number of output lines */
X    int		strip;		/* trailing space strip index */
X    char	chr;		/* single character storage */
X
X    /* loop through the input lines */
X    while ( fgets(input, LINESIZE, stdin) != (char *)NULL ) {
X
X	/* init output buffers to blanks */
X	memset( output, ' ', sizeof(output) );
X
X	/* slide through input line, dropping bs chars */
X	out_dex = -1;		/* reset array pointers */
X	in_dex = 0;
X	line = 0;
X	line_count = 0;
X
X	while ( ( chr = input[in_dex++] ) && chr != '\n' ) {
X	    if (chr != '\b') {
X		line = 0;			/* back to main line */
X		output[line][++out_dex] = chr;	/* stuff the character */
X	    } else {	/* got backspace */
X		++line;			/* select output buffer */
X		if (line == MAXOVER) {
X		    fprintf(stderr, "Too many overstrikes!\n");
X		    exit(1);
X		}
X		output[line][out_dex] = input[in_dex++];
X		line_count = (line_count < line) ? line : line_count;
X	    }
X	} /* end of input line */
X
X	/* print the output buffers */
X	for (line = 0; line <= line_count; line++) {
X	    strip = out_dex;
X	    while (output[line][strip] == ' ')	/* strip trailing spaces */
X		--strip;
X	    ++strip;				/* point past string end */
X	    if (line < line_count)		/* new line or return? */
X		output[line][strip] = '\r';
X	    else
X		output[line][strip] = '\n';
X	    output[line][++strip] = '\0';	/* terminate string */
X	    fputs (output[line], stdout);	/* print it */
X	}
X
X    } /* end of file */
X    exit(0);
X
X} /* end of main */
END_OF_FILE
if test 2474 -ne `wc -c <'nobs.c'`; then
    echo shar: \"'nobs.c'\" unpacked with wrong size!
fi
# end of 'nobs.c'
fi
echo shar: End of shell archive.
exit 0