coreutils/fold.c

   1 /* fold -- wrap each input line to fit in specified width.
   2
   3    Written by David MacKenzie, djm@gnu.ai.mit.edu.
   4    Copyright (C) 91, 1995-2002 Free Software Foundation, Inc.
   5
   6    Modified for busybox based on coreutils v 5.0
   7    Copyright (C) 2003 Glenn McGrath <bug1@iinet.net.au>
   8
   9    Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
  10 */
  11
  12 #include <ctype.h>
  13 #include <errno.h>
  14 #include <stdio.h>
  15 #include <stdlib.h>
  16 #include <string.h>
  17 #include <sys/types.h>
  18 #include <unistd.h>
  19 #include "busybox.h"
  20
  21 /* If nonzero, count bytes, not column positions. */
  22 static unsigned long flags;
  23 #define FLAG_COUNT_BYTES        1
  24 #define FLAG_BREAK_SPACES       2
  25 #define FLAG_WIDTH                      4
  26
  27 /* Assuming the current column is COLUMN, return the column that
  28    printing C will move the cursor to.
  29    The first column is 0. */
  30
  31 static int adjust_column(int column, char c)
  32 {
  33         if (!(flags & FLAG_COUNT_BYTES)) {
  34                 if (c == '\b') {
  35                         if (column > 0)
  36                                 column--;
  37                 } else if (c == '\r')
  38                         column = 0;
  39                 else if (c == '\t')
  40                         column = column + 8 - column % 8;
  41                 else                    /* if (isprint (c)) */
  42                         column++;
  43         } else
  44                 column++;
  45         return column;
  46 }
  47
  48 extern int fold_main(int argc, char **argv)
  49 {
  50         char *w_opt;
  51         int width = 80;
  52         int i;
  53         int errs = 0;
  54
  55
  56 #ifdef CONFIG_FEATURE_SUSv2_OBSOLETE
  57         /* Turn any numeric options into -w options.  */
  58         for (i = 1; i < argc; i++) {
  59                 char const *a = argv[i];
  60
  61                 if (a[0] == '-') {
  62                         if (a[1] == '-' && !a[2])
  63                                 break;
  64                         if (isdigit(a[1])) {
  65                                 char *s = xmalloc(strlen(a) + 2);
  66
  67                                 s[0] = '-';
  68                                 s[1] = 'w';
  69                                 strcpy(s + 2, a + 1);
  70                                 argv[i] = s;
  71                         }
  72                 }
  73         }
  74 #endif
  75
  76         flags = bb_getopt_ulflags(argc, argv, "bsw:", &w_opt);
  77         if (flags & FLAG_WIDTH)
  78                 width = bb_xgetlarg(w_opt, 10, 1, 10000);
  79
  80         argv += optind;
  81         if (!*argv) {
  82                 *--argv = "-";
  83         }
  84
  85         do {
  86                 FILE *istream = bb_wfopen_input(*argv);
  87                 if (istream != NULL) {
  88                         int c;
  89                         int column = 0;         /* Screen column where next char will go. */
  90                         int offset_out = 0;     /* Index in `line_out' for next char. */
  91                         static char *line_out = NULL;
  92                         static int allocated_out = 0;
  93
  94                         while ((c = getc(istream)) != EOF) {
  95                                 if (offset_out + 1 >= allocated_out) {
  96                                         allocated_out += 1024;
  97                                         line_out = xrealloc(line_out, allocated_out);
  98                                 }
  99
 100                                 if (c == '\n') {
 101                                         line_out[offset_out++] = c;
 102                                         fwrite(line_out, sizeof(char), (size_t) offset_out, stdout);
 103                                         column = offset_out = 0;
 104                                         continue;
 105                                 }
 106
 107 rescan:
 108                                 column = adjust_column(column, c);
 109
 110                                 if (column > width) {
 111                                         /* This character would make the line too long.
 112                                            Print the line plus a newline, and make this character
 113                                            start the next line. */
 114                                         if (flags & FLAG_BREAK_SPACES) {
 115                                                 /* Look for the last blank. */
 116                                                 int logical_end;
 117
 118                                                 for (logical_end = offset_out - 1; logical_end >= 0; logical_end--) {
 119                                                         if (isblank(line_out[logical_end])) {
 120                                                                 break;
 121                                                         }
 122                                                 }
 123                                                 if (logical_end >= 0) {
 124                                                         /* Found a blank.  Don't output the part after it. */
 125                                                         logical_end++;
 126                                                         fwrite(line_out, sizeof(char), (size_t) logical_end, stdout);
 127                                                         putchar('\n');
 128                                                         /* Move the remainder to the beginning of the next line.
 129                                                            The areas being copied here might overlap. */
 130                                                         memmove(line_out, line_out + logical_end, offset_out - logical_end);
 131                                                         offset_out -= logical_end;
 132                                                         for (column = i = 0; i < offset_out; i++) {
 133                                                                 column = adjust_column(column, line_out[i]);
 134                                                         }
 135                                                         goto rescan;
 136                                                 }
 137                                         } else {
 138                                                 if (offset_out == 0) {
 139                                                         line_out[offset_out++] = c;
 140                                                         continue;
 141                                                 }
 142                                         }
 143                                         line_out[offset_out++] = '\n';
 144                                         fwrite(line_out, sizeof(char), (size_t) offset_out, stdout);
 145                                         column = offset_out = 0;
 146                                         goto rescan;
 147                                 }
 148
 149                                 line_out[offset_out++] = c;
 150                         }
 151
 152                         if (offset_out) {
 153                                 fwrite(line_out, sizeof(char), (size_t) offset_out, stdout);
 154                         }
 155
 156                         if (ferror(istream) || bb_fclose_nonstdin(istream)) {
 157                                 bb_perror_msg("%s", *argv);     /* Avoid multibyte problems. */
 158                                 errs |= EXIT_FAILURE;
 159                         }
 160                 } else {
 161                         errs |= EXIT_FAILURE;
 162                 }
 163         } while (*++argv);
 164
 165         bb_fflush_stdout_and_exit(errs);
 166 }
 167 /* vi: set sw=4 ts=4: */