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 static unsigned long flags;
  22 #define FLAG_COUNT_BYTES        1
  23 #define FLAG_BREAK_SPACES       2
  24 #define FLAG_WIDTH                      4
  25
  26 /* Assuming the current column is COLUMN, return the column that
  27    printing C will move the cursor to.
  28    The first column is 0. */
  29
  30 static int adjust_column(int column, char c)
  31 {
  32         if (!(flags & FLAG_COUNT_BYTES)) {
  33                 if (c == '\b') {
  34                         if (column > 0)
  35                                 column--;
  36                 } else if (c == '\r')
  37                         column = 0;
  38                 else if (c == '\t')
  39                         column = column + 8 - column % 8;
  40                 else                    /* if (isprint (c)) */
  41                         column++;
  42         } else
  43                 column++;
  44         return column;
  45 }
  46
  47 extern int fold_main(int argc, char **argv)
  48 {
  49         char *w_opt;
  50         int width = 80;
  51         int i;
  52         int errs = 0;
  53
  54
  55         if(!ENABLE_DEBUG_YANK_SUSv2) {
  56                 /* Turn any numeric options into -w options.  */
  57                 for (i = 1; i < argc; i++) {
  58                         char const *a = argv[i];
  59
  60                         if (*a++ == '-') {
  61                                 if (*a == '-' && !a[1])
  62                                         break;
  63                                 if (isdigit(*a)) {
  64                                         argv[i] = bb_xasprintf("-w%s", a);
  65                                 }
  66                         }
  67                 }
  68         }
  69
  70         flags = bb_getopt_ulflags(argc, argv, "bsw:", &w_opt);
  71         if (flags & FLAG_WIDTH)
  72                 width = bb_xgetlarg(w_opt, 10, 1, 10000);
  73
  74         argv += optind;
  75         if (!*argv) {
  76                 *--argv = "-";
  77         }
  78
  79         do {
  80                 FILE *istream = bb_wfopen_input(*argv);
  81                 if (istream != NULL) {
  82                         int c;
  83                         int column = 0;         /* Screen column where next char will go. */
  84                         int offset_out = 0;     /* Index in `line_out' for next char. */
  85                         static char *line_out = NULL;
  86                         static int allocated_out = 0;
  87
  88                         while ((c = getc(istream)) != EOF) {
  89                                 if (offset_out + 1 >= allocated_out) {
  90                                         allocated_out += 1024;
  91                                         line_out = xrealloc(line_out, allocated_out);
  92                                 }
  93
  94                                 if (c == '\n') {
  95                                         line_out[offset_out++] = c;
  96                                         fwrite(line_out, sizeof(char), (size_t) offset_out, stdout);
  97                                         column = offset_out = 0;
  98                                         continue;
  99                                 }
 100
 101 rescan:
 102                                 column = adjust_column(column, c);
 103
 104                                 if (column > width) {
 105                                         /* This character would make the line too long.
 106                                            Print the line plus a newline, and make this character
 107                                            start the next line. */
 108                                         if (flags & FLAG_BREAK_SPACES) {
 109                                                 /* Look for the last blank. */
 110                                                 int logical_end;
 111
 112                                                 for (logical_end = offset_out - 1; logical_end >= 0; logical_end--) {
 113                                                         if (isblank(line_out[logical_end])) {
 114                                                                 break;
 115                                                         }
 116                                                 }
 117                                                 if (logical_end >= 0) {
 118                                                         /* Found a blank.  Don't output the part after it. */
 119                                                         logical_end++;
 120                                                         fwrite(line_out, sizeof(char), (size_t) logical_end, stdout);
 121                                                         putchar('\n');
 122                                                         /* Move the remainder to the beginning of the next line.
 123                                                            The areas being copied here might overlap. */
 124                                                         memmove(line_out, line_out + logical_end, offset_out - logical_end);
 125                                                         offset_out -= logical_end;
 126                                                         for (column = i = 0; i < offset_out; i++) {
 127                                                                 column = adjust_column(column, line_out[i]);
 128                                                         }
 129                                                         goto rescan;
 130                                                 }
 131                                         } else {
 132                                                 if (offset_out == 0) {
 133                                                         line_out[offset_out++] = c;
 134                                                         continue;
 135                                                 }
 136                                         }
 137                                         line_out[offset_out++] = '\n';
 138                                         fwrite(line_out, sizeof(char), (size_t) offset_out, stdout);
 139                                         column = offset_out = 0;
 140                                         goto rescan;
 141                                 }
 142
 143                                 line_out[offset_out++] = c;
 144                         }
 145
 146                         if (offset_out) {
 147                                 fwrite(line_out, sizeof(char), (size_t) offset_out, stdout);
 148                         }
 149
 150                         if (ferror(istream) || bb_fclose_nonstdin(istream)) {
 151                                 bb_perror_msg("%s", *argv);     /* Avoid multibyte problems. */
 152                                 errs |= EXIT_FAILURE;
 153                         }
 154                 } else {
 155                         errs |= EXIT_FAILURE;
 156                 }
 157         } while (*++argv);
 158
 159         bb_fflush_stdout_and_exit(errs);
 160 }
 161 /* vi: set sw=4 ts=4: */