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colrm.c revision 1.7.28.1 
      1 /*	$NetBSD: colrm.c,v 1.7.28.1 2008/09/18 04:29:09 wrstuden Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1991, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 #ifndef lint
     34 __COPYRIGHT("@(#) Copyright (c) 1991, 1993\
     35  The Regents of the University of California.  All rights reserved.");
     36 #endif /* not lint */
     37 
     38 #ifndef lint
     39 #if 0
     40 static char sccsid[] = "@(#)colrm.c	8.2 (Berkeley) 5/4/95";
     41 #endif
     42 __RCSID("$NetBSD: colrm.c,v 1.7.28.1 2008/09/18 04:29:09 wrstuden Exp $");
     43 #endif /* not lint */
     44 
     45 #include <sys/types.h>
     46 
     47 #include <err.h>
     48 #include <errno.h>
     49 #include <limits.h>
     50 #include <stdio.h>
     51 #include <stdlib.h>
     52 #include <string.h>
     53 #include <unistd.h>
     54 
     55 #define	TAB	8
     56 
     57 void	check(FILE *);
     58 void	usage(void);
     59 
     60 int
     61 main(int argc, char *argv[])
     62 {
     63 	u_long column, start, stop;
     64 	int ch;
     65 	char *p;
     66 
     67 	while ((ch = getopt(argc, argv, "")) != -1)
     68 		switch(ch) {
     69 		case '?':
     70 		default:
     71 			usage();
     72 		}
     73 	argc -= optind;
     74 	argv += optind;
     75 
     76 	start = stop = 0;
     77 	switch(argc) {
     78 	case 2:
     79 		stop = strtol(argv[1], &p, 10);
     80 		if (stop <= 0 || *p)
     81 			errx(1, "illegal column -- %s", argv[1]);
     82 		/* FALLTHROUGH */
     83 	case 1:
     84 		start = strtol(argv[0], &p, 10);
     85 		if (start <= 0 || *p)
     86 			errx(1, "illegal column -- %s", argv[0]);
     87 		break;
     88 	case 0:
     89 		break;
     90 	default:
     91 		usage();
     92 	}
     93 
     94 	if (stop && start > stop)
     95 		err(1, "illegal start and stop columns");
     96 
     97 	for (column = 0;;) {
     98 		switch (ch = getchar()) {
     99 		case EOF:
    100 			check(stdin);
    101 			break;
    102 		case '\b':
    103 			if (column)
    104 				--column;
    105 			break;
    106 		case '\n':
    107 			column = 0;
    108 			break;
    109 		case '\t':
    110 			column = (column + TAB) & ~(TAB - 1);
    111 			break;
    112 		default:
    113 			++column;
    114 			break;
    115 		}
    116 
    117 		if ((!start || column < start || (stop && column > stop)) &&
    118 		    putchar(ch) == EOF)
    119 			check(stdout);
    120 	}
    121 }
    122 
    123 void
    124 check(FILE *stream)
    125 {
    126 	if (feof(stream))
    127 		exit(0);
    128 	if (ferror(stream))
    129 		err(1, "%s", stream == stdin ? "stdin" : "stdout");
    130 }
    131 
    132 void
    133 usage()
    134 {
    135 	(void)fprintf(stderr, "usage: colrm [start [stop]]\n");
    136 	exit(1);
    137 }
    138