usr.bin/colrm/colrm.c

   1 /*-
   2  * Copyright (c) 1991, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  * $FreeBSD: src/usr.bin/colrm/colrm.c,v 1.7.2.1 2001/08/02 01:33:29 obrien Exp $
  34  * $DragonFly: src/usr.bin/colrm/colrm.c,v 1.5 2005/08/04 17:31:22 drhodus Exp $
  35  *
  36  * @(#) Copyright (c) 1991, 1993 The Regents of the University of California.  All rights reserved.
  37  * @(#)colrm.c  8.2 (Berkeley) 5/4/95
  38  */
  39
  40 #include <sys/types.h>
  41 #include <limits.h>
  42 #include <err.h>
  43 #include <errno.h>
  44 #include <stdio.h>
  45 #include <stdlib.h>
  46 #include <string.h>
  47 #include <unistd.h>
  48
  49 #define TAB     8
  50
  51 int main(int, char *[]);
  52 void check(FILE *);
  53 static void usage(void);
  54
  55 int
  56 main(int argc, char **argv)
  57 {
  58         u_long column, start, stop;
  59         int ch;
  60         char *p;
  61
  62         while ((ch = getopt(argc, argv, "")) != -1)
  63                 switch(ch) {
  64                 case '?':
  65                 default:
  66                         usage();
  67                 }
  68         argc -= optind;
  69         argv += optind;
  70
  71         start = stop = 0;
  72         switch(argc) {
  73         case 2:
  74                 stop = strtol(argv[1], &p, 10);
  75                 if (stop <= 0 || *p)
  76                         errx(1, "illegal column -- %s", argv[1]);
  77                 /* FALLTHROUGH */
  78         case 1:
  79                 start = strtol(argv[0], &p, 10);
  80                 if (start <= 0 || *p)
  81                         errx(1, "illegal column -- %s", argv[0]);
  82                 break;
  83         case 0:
  84                 break;
  85         default:
  86                 usage();
  87         }
  88
  89         if (stop && start > stop)
  90                 errx(1, "illegal start and stop columns");
  91
  92         for (column = 0;;) {
  93                 switch (ch = getchar()) {
  94                 case EOF:
  95                         check(stdin);
  96                         break;
  97                 case '\b':
  98                         if (column)
  99                                 --column;
 100                         break;
 101                 case '\n':
 102                         column = 0;
 103                         break;
 104                 case '\t':
 105                         column = (column + TAB) & ~(TAB - 1);
 106                         break;
 107                 default:
 108                         ++column;
 109                         break;
 110                 }
 111
 112                 if ((!start || column < start || (stop && column > stop)) &&
 113                     putchar(ch) == EOF)
 114                         check(stdout);
 115         }
 116 }
 117
 118 void
 119 check(FILE *stream)
 120 {
 121         if (feof(stream))
 122                 exit(0);
 123         if (ferror(stream))
 124                 err(1, "%s", stream == stdin ? "stdin" : "stdout");
 125 }
 126
 127 void
 128 usage(void)
 129 {
 130         (void)fprintf(stderr, "usage: colrm [start [stop]]\n");
 131         exit(1);
 132 }
 133