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