usr.bin/expand/expand.c

   1 /*      $NetBSD: expand.c,v 1.12 2008/07/21 14:19:22 lukem Exp $        */
   2
   3 /*
   4  * Copyright (c) 1980, 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) 1980, 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[] = "@(#)expand.c    8.1 (Berkeley) 6/9/93";
  41 #endif
  42 __RCSID("$NetBSD: expand.c,v 1.12 2008/07/21 14:19:22 lukem Exp $");
  43 #endif /* not lint */
  44
  45 #include <stdio.h>
  46 #include <stdlib.h>
  47 #include <ctype.h>
  48 #include <unistd.h>
  49 #include <err.h>
  50
  51 /*
  52  * expand - expand tabs to equivalent spaces
  53  */
  54 size_t  nstops;
  55 size_t  tabstops[100];
  56
  57 static  void    getstops(const char *);
  58         int     main(int, char **);
  59 static  void    usage(void) __dead;
  60
  61 int
  62 main(int argc, char *argv[])
  63 {
  64         int c;
  65         size_t n, column;
  66
  67         setprogname(argv[0]);
  68
  69         /* handle obsolete syntax */
  70         while (argc > 1 &&
  71             argv[1][0] == '-' && isdigit((unsigned char)argv[1][1])) {
  72                 getstops(&argv[1][1]);
  73                 argc--; argv++;
  74         }
  75
  76         while ((c = getopt (argc, argv, "t:")) != -1) {
  77                 switch (c) {
  78                 case 't':
  79                         getstops(optarg);
  80                         break;
  81                 case '?':
  82                 default:
  83                         usage();
  84                         /* NOTREACHED */
  85                 }
  86         }
  87         argc -= optind;
  88         argv += optind;
  89
  90         do {
  91                 if (argc > 0) {
  92                         if (freopen(argv[0], "r", stdin) == NULL)
  93                                 err(EXIT_FAILURE, "Cannot open `%s'", argv[0]);
  94                         argc--, argv++;
  95                 }
  96                 column = 0;
  97                 while ((c = getchar()) != EOF) {
  98                         switch (c) {
  99                         case '\t':
 100                                 if (nstops == 0) {
 101                                         do {
 102                                                 putchar(' ');
 103                                                 column++;
 104                                         } while (column & 07);
 105                                         continue;
 106                                 }
 107                                 if (nstops == 1) {
 108                                         do {
 109                                                 putchar(' ');
 110                                                 column++;
 111                                         } while (((column - 1) % tabstops[0])
 112                                             != (tabstops[0] - 1));
 113                                         continue;
 114                                 }
 115                                 for (n = 0; n < nstops; n++)
 116                                         if (tabstops[n] > column)
 117                                                 break;
 118                                 if (n == nstops) {
 119                                         putchar(' ');
 120                                         column++;
 121                                         continue;
 122                                 }
 123                                 while (column < tabstops[n]) {
 124                                         putchar(' ');
 125                                         column++;
 126                                 }
 127                                 continue;
 128
 129                         case '\b':
 130                                 if (column)
 131                                         column--;
 132                                 putchar('\b');
 133                                 continue;
 134
 135                         default:
 136                                 putchar(c);
 137                                 column++;
 138                                 continue;
 139
 140                         case '\n':
 141                                 putchar(c);
 142                                 column = 0;
 143                                 continue;
 144                         }
 145                 }
 146         } while (argc > 0);
 147         return EXIT_SUCCESS;
 148 }
 149
 150 static void
 151 getstops(const char *spec)
 152 {
 153         int i;
 154         const char *cp = spec;
 155
 156         nstops = 0;
 157         for (;;) {
 158                 i = 0;
 159                 while (*cp >= '0' && *cp <= '9')
 160                         i = i * 10 + *cp++ - '0';
 161                 if (i <= 0 || i > 256)
 162                         errx(EXIT_FAILURE, "Too large tab stop spec `%d'", i);
 163                 if (nstops > 0 && (size_t)i <= tabstops[nstops-1])
 164                         errx(EXIT_FAILURE, "Out of order tabstop spec `%d'", i);
 165                 if (nstops == sizeof(tabstops) / sizeof(tabstops[0]) - 1)
 166                         errx(EXIT_FAILURE, "Too many tabstops");
 167                 tabstops[nstops++] = i;
 168                 if (*cp == '\0')
 169                         break;
 170                 if (*cp != ',' && *cp != ' ')
 171                         errx(EXIT_FAILURE, "Illegal tab stop spec `%s'", spec);
 172                 cp++;
 173         }
 174 }
 175
 176 static void
 177 usage(void)
 178 {
 179
 180         (void)fprintf(stderr, "Usage: %s [-t tablist] [file ...]\n",
 181             getprogname());
 182         exit(EXIT_FAILURE);
 183 }