usr.bin/fold/fold.c

   1 /*-
   2  * Copyright (c) 1990, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Kevin Ruddy.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  *
  36  * @(#) Copyright (c) 1990, 1993 The Regents of the University of California.  All rights reserved.
  37  * @(#)fold.c   8.1 (Berkeley) 6/6/93
  38  * $FreeBSD: src/usr.bin/fold/fold.c,v 1.4.2.3 2002/07/11 01:01:44 tjr Exp $
  39  * $DragonFly: src/usr.bin/fold/fold.c,v 1.5 2006/08/13 02:15:07 swildner Exp $
  40  */
  41
  42 #include <ctype.h>
  43 #include <err.h>
  44 #include <limits.h>
  45 #include <locale.h>
  46 #include <stdio.h>
  47 #include <stdlib.h>
  48 #include <string.h>
  49 #include <unistd.h>
  50
  51 #define DEFLINEWIDTH    80
  52
  53 void fold(int);
  54 static int newpos(int, int);
  55 static void usage(void);
  56
  57 int bflag;                      /* Count bytes, not columns */
  58 int sflag;                      /* Split on word boundaries */
  59
  60 int
  61 main(int argc, char **argv)
  62 {
  63         int ch;
  64         int rval, width;
  65         char *p;
  66
  67         (void) setlocale(LC_CTYPE, "");
  68
  69         width = -1;
  70         while ((ch = getopt(argc, argv, "0123456789bsw:")) != -1)
  71                 switch (ch) {
  72                 case 'b':
  73                         bflag = 1;
  74                         break;
  75                 case 's':
  76                         sflag = 1;
  77                         break;
  78                 case 'w':
  79                         if ((width = atoi(optarg)) <= 0) {
  80                                 errx(1, "illegal width value");
  81                         }
  82                         break;
  83                 case '0': case '1': case '2': case '3': case '4':
  84                 case '5': case '6': case '7': case '8': case '9':
  85                         if (width == -1) {
  86                                 p = argv[optind - 1];
  87                                 if (p[0] == '-' && p[1] == ch && !p[2])
  88                                         width = atoi(++p);
  89                                 else
  90                                         width = atoi(argv[optind] + 1);
  91                         }
  92                         break;
  93                 default:
  94                         usage();
  95                 }
  96         argv += optind;
  97         argc -= optind;
  98
  99         if (width == -1)
 100                 width = DEFLINEWIDTH;
 101         rval = 0;
 102         if (!*argv)
 103                 fold(width);
 104         else for (; *argv; ++argv)
 105                 if (!freopen(*argv, "r", stdin)) {
 106                         warn("%s", *argv);
 107                         rval = 1;
 108                 } else
 109                         fold(width);
 110         exit(rval);
 111 }
 112
 113 static void
 114 usage(void)
 115 {
 116         (void)fprintf(stderr, "usage: fold [-bs] [-w width] [file ...]\n");
 117         exit(1);
 118 }
 119
 120 /*
 121  * Fold the contents of standard input to fit within WIDTH columns (or bytes)
 122  * and write to standard output.
 123  *
 124  * If sflag is set, split the line at the last space character on the line.
 125  * This flag necessitates storing the line in a buffer until the current
 126  * column > width, or a newline or EOF is read.
 127  *
 128  * The buffer can grow larger than WIDTH due to backspaces and carriage
 129  * returns embedded in the input stream.
 130  */
 131 void
 132 fold(int width)
 133 {
 134         static char *buf;
 135         static int buf_max;
 136         int ch, col, i, indx, space;
 137
 138         col = indx = space = 0;
 139         while ((ch = getchar()) != EOF) {
 140                 if (ch == '\n') {
 141                         if (indx != 0)
 142                                 fwrite(buf, 1, indx, stdout);
 143                         putchar('\n');
 144                         col = indx = 0;
 145                         continue;
 146                 }
 147                 if ((col = newpos(col, ch)) > width) {
 148                         if (sflag) {
 149                                 i = indx;
 150                                 while (--i >= 0 && !isblank((unsigned char)buf[i]))
 151                                         ;
 152                                 space = i;
 153                         }
 154                         if (sflag && space != -1) {
 155                                 space++;
 156                                 fwrite(buf, 1, space, stdout);
 157                                 memmove(buf, buf + space, indx - space);
 158                                 indx -= space;
 159                                 col = 0;
 160                                 for (i = 0; i < indx; i++)
 161                                         col = newpos(col,
 162                                             (unsigned char)buf[i]);
 163                         } else {
 164                                 fwrite(buf, 1, indx, stdout);
 165                                 col = indx = 0;
 166                         }
 167                         putchar('\n');
 168                         col = newpos(col, ch);
 169                 }
 170                 if (indx + 1 > buf_max) {
 171                         buf_max += LINE_MAX;
 172                         if ((buf = realloc(buf, buf_max)) == NULL)
 173                                 err(1, "realloc()");
 174                 }
 175                 buf[indx++] = ch;
 176         }
 177
 178         if (indx != 0)
 179                 fwrite(buf, 1, indx, stdout);
 180 }
 181
 182 /*
 183  * Update the current column position for a character.
 184  */
 185 static int
 186 newpos(int col, int ch)
 187 {
 188
 189         if (bflag)
 190                 ++col;
 191         else
 192                 switch (ch) {
 193                 case '\b':
 194                         if (col > 0)
 195                                 --col;
 196                         break;
 197                 case '\r':
 198                         col = 0;
 199                         break;
 200                 case '\t':
 201                         col = (col + 8) & ~7;
 202                         break;
 203                 default:
 204                         if (isprint(ch))
 205                                 ++col;
 206                         break;
 207                 }
 208
 209         return (col);
 210 }