usr.bin/unexpand/unexpand.c

   1 /*      $NetBSD: unexpand.c,v 1.13 2008/07/21 14:19:27 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[] = "@(#)unexpand.c  8.1 (Berkeley) 6/6/93";
  41 #endif
  42 __RCSID("$NetBSD: unexpand.c,v 1.13 2008/07/21 14:19:27 lukem Exp $");
  43 #endif /* not lint */
  44
  45 /*
  46  * unexpand - put tabs into a file replacing blanks
  47  */
  48 #include <limits.h>
  49 #include <stdio.h>
  50 #include <stdlib.h>
  51 #include <string.h>
  52 #include <unistd.h>
  53 #include <errno.h>
  54 #include <err.h>
  55 #include <util.h>
  56
  57
  58 #define DSTOP   8
  59 static int      all;
  60 static size_t   nstops;
  61 static size_t   maxstops;
  62 static size_t   *tabstops;
  63
  64 static void     tabify(const char *, size_t);
  65 static void     usage(void) __attribute__((__noreturn__));
  66
  67 static void
  68 usage(void)
  69 {
  70     (void)fprintf(stderr, "Usage: %s [-a] [-t tabstop] [file ...]\n",
  71         getprogname());
  72     exit(EXIT_FAILURE);
  73 }
  74
  75 int
  76 main(int argc, char **argv)
  77 {
  78         int c;
  79         char *ep, *tab;
  80         char *line;
  81         size_t len;
  82         unsigned long i;
  83
  84         setprogname(argv[0]);
  85
  86         while ((c = getopt(argc, argv, "at:")) != -1) {
  87                 switch (c) {
  88                 case 'a':
  89                         if (nstops)
  90                                 usage();
  91                         all++;
  92                         break;
  93                 case 't':
  94                         if (all)
  95                                 usage();
  96                         while ((tab = strsep(&optarg, ", \t")) != NULL) {
  97                                 if (*tab == '\0')
  98                                         continue;
  99                                 errno = 0;
 100                                 i = strtoul(tab, &ep, 0);
 101                                 if (*ep || (errno == ERANGE && i == ULONG_MAX))
 102                                         errx(EXIT_FAILURE,
 103                                             "Invalid tabstop `%s'", tab);
 104                                 if (nstops >= maxstops) {
 105                                         maxstops += 20;
 106                                         tabstops = erealloc(tabstops, maxstops);
 107                                 }
 108                                 if (nstops && tabstops[nstops - 1] >= (size_t)i)
 109                                         errx(EXIT_FAILURE,
 110                                             "Bad tabstop spec `%s', must be "
 111                                             "greater than the previous `%zu'",
 112                                             tab, tabstops[nstops - 1]);
 113                                 tabstops[nstops++] = i;
 114                         }
 115                         break;
 116                 case '?':
 117                 default:
 118                         usage();
 119                 }
 120         }
 121         argc -= optind;
 122         argv += optind;
 123
 124         for (i = 0; i < nstops; i++)
 125                 fprintf(stderr, "%lu %zu\n", i, tabstops[i]);
 126
 127         do {
 128                 if (argc > 0) {
 129                         if (freopen(argv[0], "r", stdin) == NULL)
 130                                 err(EXIT_FAILURE, "Cannot open `%s'", argv[0]);
 131                         argc--, argv++;
 132                 }
 133                 while ((line = fgetln(stdin, &len)) != NULL)
 134                         tabify(line, len);
 135         } while (argc > 0);
 136         return EXIT_SUCCESS;
 137 }
 138
 139 static void
 140 tabify(const char *line, size_t len)
 141 {
 142         const char *e, *p;
 143         size_t dcol, ocol, limit, n;
 144
 145         dcol = ocol = 0;
 146         limit = nstops == 0 ? UINT_MAX : tabstops[nstops - 1] - 1;
 147         e = line + len;
 148         for (p = line; p < e; p++) {
 149                 if (*p == ' ') {
 150                         dcol++;
 151                         continue;
 152                 } else if (*p == '\t') {
 153                         if (nstops == 0) {
 154                                 dcol = (1 + dcol / DSTOP) * DSTOP;
 155                                 continue;
 156                         } else {
 157                                 for (n = 0; tabstops[n] - 1 < dcol &&
 158                                     n < nstops; n++)
 159                                         continue;
 160                                 if (n < nstops - 1 && tabstops[n] - 1 < limit) {
 161                                         dcol = tabstops[n];
 162                                         continue;
 163                                 }
 164                         }
 165                 }
 166
 167                 /* Output our tabs */
 168                 if (nstops == 0) {
 169                         while (((ocol + DSTOP) / DSTOP) <= (dcol / DSTOP)) {
 170                                 if (dcol - ocol < 2)
 171                                         break;
 172                                 if (putchar('\t') == EOF)
 173                                         goto out;
 174                                 ocol = (1 + ocol / DSTOP) * DSTOP;
 175                         }
 176                 } else {
 177                         for (n = 0; tabstops[n] <= ocol && n < nstops; n++)
 178                                 continue;
 179                         while (tabstops[n] <= dcol && ocol < dcol &&
 180                             n < nstops && ocol < limit) {
 181                                 if (putchar('\t') == EOF)
 182                                         goto out;
 183                                 ocol = tabstops[n++];
 184                         }
 185                 }
 186
 187                 /* Output remaining spaces */
 188                 while (ocol < dcol && ocol < limit) {
 189                         if (putchar(' ') == EOF)
 190                                 goto out;
 191                         ocol++;
 192                 }
 193
 194                 /* Output our char */
 195                 if (putchar(*p) == EOF)
 196                         goto out;
 197                 if (*p == '\b') {
 198                         if (ocol > 0) {
 199                                 ocol--;
 200                                 dcol--;
 201                         }
 202                 } else {
 203                         ocol++;
 204                         dcol++;
 205                 }
 206
 207                 /* Output remainder of line */
 208                 if (!all || dcol >= limit) {
 209                         for (p++; p < e; p++)
 210                                 if (putchar(*p) == EOF)
 211                                         goto out;
 212                         return;
 213                 }
 214         }
 215         return;
 216 out:
 217         err(EXIT_FAILURE, "write failed");
 218 }