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. Neither the name of the University nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  *
  32  * @(#) Copyright (c) 1990, 1993 The Regents of the University of California.  All rights reserved.
  33  * @(#)fold.c   8.1 (Berkeley) 6/6/93
  34  * $FreeBSD: head/usr.bin/fold/fold.c 227165 2011-11-06 08:15:23Z ed $
  35  */
  36
  37 #include <err.h>
  38 #include <limits.h>
  39 #include <locale.h>
  40 #include <stdio.h>
  41 #include <stdlib.h>
  42 #include <string.h>
  43 #include <unistd.h>
  44 #include <wchar.h>
  45 #include <wctype.h>
  46
  47 #define DEFLINEWIDTH    80
  48
  49 void fold(int);
  50 static int newpos(int, wint_t);
  51 static void usage(void);
  52
  53 static int bflag;               /* Count bytes, not columns */
  54 static int sflag;               /* Split on word boundaries */
  55
  56 int
  57 main(int argc, char **argv)
  58 {
  59         int ch, previous_ch;
  60         int rval, width;
  61
  62         (void) setlocale(LC_CTYPE, "");
  63
  64         width = -1;
  65         previous_ch = 0;
  66         while ((ch = getopt(argc, argv, "0123456789bsw:")) != -1) {
  67                 switch (ch) {
  68                 case 'b':
  69                         bflag = 1;
  70                         break;
  71                 case 's':
  72                         sflag = 1;
  73                         break;
  74                 case 'w':
  75                         if ((width = atoi(optarg)) <= 0) {
  76                                 errx(1, "illegal width value");
  77                         }
  78                         break;
  79                 case '0': case '1': case '2': case '3': case '4':
  80                 case '5': case '6': case '7': case '8': case '9':
  81                         /* Accept a width as eg. -30. Note that a width
  82                          * specified using the -w option is always used prior
  83                          * to this undocumented option. */
  84                         switch (previous_ch) {
  85                         case '0': case '1': case '2': case '3': case '4':
  86                         case '5': case '6': case '7': case '8': case '9':
  87                                 /* The width is a number with multiple digits:
  88                                  * add the last one. */
  89                                 width = width * 10 + (ch - '0');
  90                                 break;
  91                         default:
  92                                 /* Set the width, unless it was previously
  93                                  * set. For instance, the following options
  94                                  * would all give a width of 5 and not 10:
  95                                  *   -10 -w5
  96                                  *   -5b10
  97                                  *   -5 -10b */
  98                                 if (width == -1)
  99                                         width = ch - '0';
 100                                 break;
 101                         }
 102                         break;
 103                 default:
 104                         usage();
 105                 }
 106                 previous_ch = ch;
 107         }
 108         argv += optind;
 109         argc -= optind;
 110
 111         if (width == -1)
 112                 width = DEFLINEWIDTH;
 113         rval = 0;
 114         if (!*argv)
 115                 fold(width);
 116         else for (; *argv; ++argv)
 117                 if (!freopen(*argv, "r", stdin)) {
 118                         warn("%s", *argv);
 119                         rval = 1;
 120                 } else
 121                         fold(width);
 122         exit(rval);
 123 }
 124
 125 static void
 126 usage(void)
 127 {
 128         (void)fprintf(stderr, "usage: fold [-bs] [-w width] [file ...]\n");
 129         exit(1);
 130 }
 131
 132 /*
 133  * Fold the contents of standard input to fit within WIDTH columns (or bytes)
 134  * and write to standard output.
 135  *
 136  * If sflag is set, split the line at the last space character on the line.
 137  * This flag necessitates storing the line in a buffer until the current
 138  * column > width, or a newline or EOF is read.
 139  *
 140  * The buffer can grow larger than WIDTH due to backspaces and carriage
 141  * returns embedded in the input stream.
 142  */
 143 void
 144 fold(int width)
 145 {
 146         static wchar_t *buf;
 147         static int buf_max;
 148         int col, i, indx, space;
 149         wint_t ch;
 150
 151         col = indx = 0;
 152         while ((ch = getwchar()) != WEOF) {
 153                 if (ch == '\n') {
 154                         wprintf(L"%.*ls\n", indx, buf);
 155                         col = indx = 0;
 156                         continue;
 157                 }
 158                 if ((col = newpos(col, ch)) > width) {
 159                         if (sflag) {
 160                                 i = indx;
 161                                 while (--i >= 0 && !iswblank(buf[i]))
 162                                         ;
 163                                 space = i;
 164                         }
 165                         if (sflag && space != -1) {
 166                                 space++;
 167                                 wprintf(L"%.*ls\n", space, buf);
 168                                 wmemmove(buf, buf + space, indx - space);
 169                                 indx -= space;
 170                                 col = 0;
 171                                 for (i = 0; i < indx; i++)
 172                                         col = newpos(col, buf[i]);
 173                         } else {
 174                                 wprintf(L"%.*ls\n", indx, buf);
 175                                 col = indx = 0;
 176                         }
 177                         col = newpos(col, ch);
 178                 }
 179                 if (indx + 1 > buf_max) {
 180                         buf_max += LINE_MAX;
 181                         buf = realloc(buf, sizeof(*buf) * buf_max);
 182                         if (buf == NULL)
 183                                 err(1, "realloc()");
 184                 }
 185                 buf[indx++] = ch;
 186         }
 187
 188         if (indx != 0)
 189                 wprintf(L"%.*ls", indx, buf);
 190 }
 191
 192 /*
 193  * Update the current column position for a character.
 194  */
 195 static int
 196 newpos(int col, wint_t ch)
 197 {
 198         char buf[MB_LEN_MAX];
 199         size_t len;
 200         int w;
 201
 202         if (bflag) {
 203                 len = wcrtomb(buf, ch, NULL);
 204                 col += len;
 205         } else
 206                 switch (ch) {
 207                 case '\b':
 208                         if (col > 0)
 209                                 --col;
 210                         break;
 211                 case '\r':
 212                         col = 0;
 213                         break;
 214                 case '\t':
 215                         col = (col + 8) & ~7;
 216                         break;
 217                 default:
 218                         if ((w = wcwidth(ch)) > 0)
 219                                 col += w;
 220                         break;
 221                 }
 222
 223         return (col);
 224 }