1 /* vi: set sw=4 ts=4: */
2 /* fold -- wrap each input line to fit in specified width.
4 Written by David MacKenzie, djm@gnu.ai.mit.edu.
5 Copyright (C) 91, 1995-2002 Free Software Foundation, Inc.
7 Modified for busybox based on coreutils v 5.0
8 Copyright (C) 2003 Glenn McGrath
10 Licensed under GPLv2 or later, see file LICENSE in this source tree.
13 //config: bool "fold (4.6 kb)"
16 //config: Wrap text to fit a specific width.
18 //applet:IF_FOLD(APPLET_NOEXEC(fold, fold, BB_DIR_USR_BIN, BB_SUID_DROP, fold))
20 //kbuild:lib-$(CONFIG_FOLD) += fold.o
22 //usage:#define fold_trivial_usage
23 //usage: "[-bs] [-w WIDTH] [FILE]..."
24 //usage:#define fold_full_usage "\n\n"
25 //usage: "Wrap input lines in each FILE (or stdin), writing to stdout\n"
26 //usage: "\n -b Count bytes rather than columns"
27 //usage: "\n -s Break at spaces"
28 //usage: "\n -w Use WIDTH columns instead of 80"
33 /* This is a NOEXEC applet. Be very careful! */
35 /* Must match getopt32 call */
36 #define FLAG_COUNT_BYTES 1
37 #define FLAG_BREAK_SPACES 2
40 /* Assuming the current column is COLUMN, return the column that
41 printing C will move the cursor to.
42 The first column is 0. */
43 static int adjust_column(unsigned column, char c)
45 if (option_mask32 & FLAG_COUNT_BYTES)
49 return column + 8 - column % 8;
52 if ((int)--column < 0)
57 else { /* just a printable char */
58 if (unicode_status != UNICODE_ON /* every byte is a new char */
59 || (c & 0xc0) != 0x80 /* it isn't a 2nd+ byte of a Unicode char */
67 /* Note that this function can write NULs, unlike fputs etc. */
68 static void write2stdout(const void *buf, unsigned size)
70 fwrite(buf, 1, size, stdout);
73 int fold_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
74 int fold_main(int argc UNUSED_PARAM, char **argv)
76 char *line_out = NULL;
77 const char *w_opt = "80";
79 smallint exitcode = EXIT_SUCCESS;
83 if (ENABLE_INCLUDE_SUSv2) {
84 /* Turn any numeric options into -w options. */
86 for (i = 1; argv[i]; i++) {
87 const char *a = argv[i];
90 if (*a == '-' && !a[1]) /* "--" */
93 argv[i] = xasprintf("-w%s", a);
98 getopt32(argv, "bsw:", &w_opt);
99 width = xatou_range(w_opt, 1, 10000);
103 *--argv = (char*)"-";
106 FILE *istream = fopen_or_warn_stdin(*argv);
108 unsigned column = 0; /* Screen column where next char will go */
109 unsigned offset_out = 0; /* Index in 'line_out' for next char */
111 if (istream == NULL) {
112 exitcode = EXIT_FAILURE;
116 while ((c = getc(istream)) != EOF) {
117 /* We grow line_out in chunks of 0x1000 bytes */
118 if ((offset_out & 0xfff) == 0) {
119 line_out = xrealloc(line_out, offset_out + 0x1000);
122 line_out[offset_out] = c;
124 write2stdout(line_out, offset_out + 1);
125 column = offset_out = 0;
128 column = adjust_column(column, c);
129 if (column <= width || offset_out == 0) {
130 /* offset_out == 0 case happens
131 * with small width (say, 1) and tabs.
132 * The very first tab already goes to column 8,
133 * but we must not wrap it */
138 /* This character would make the line too long.
139 * Print the line plus a newline, and make this character
140 * start the next line */
141 if (option_mask32 & FLAG_BREAK_SPACES) {
143 unsigned logical_end;
145 /* Look for the last blank. */
146 for (logical_end = offset_out - 1; (int)logical_end >= 0; logical_end--) {
147 if (!isblank(line_out[logical_end]))
150 /* Found a space or tab.
151 * Output up to and including it, and start a new line */
153 /*line_out[logical_end] = '\n'; - NO! this nukes one buffered character */
154 write2stdout(line_out, logical_end);
156 /* Move the remainder to the beginning of the next line.
157 * The areas being copied here might overlap. */
158 memmove(line_out, line_out + logical_end, offset_out - logical_end);
159 offset_out -= logical_end;
160 for (column = i = 0; i < offset_out; i++) {
161 column = adjust_column(column, line_out[i]);
165 /* No blank found, wrap will split the overlong word */
167 /* Output what we accumulated up to now, and start a new line */
168 line_out[offset_out] = '\n';
169 write2stdout(line_out, offset_out + 1);
170 column = offset_out = 0;
172 } /* while (not EOF) */
175 write2stdout(line_out, offset_out);
178 if (fclose_if_not_stdin(istream)) {
179 bb_simple_perror_msg(*argv);
180 exitcode = EXIT_FAILURE;
184 fflush_stdout_and_exit(exitcode);