busybox/coreutils/fold.c

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/* vi: set sw=4 ts=4: */
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/* fold -- wrap each input line to fit in specified width.
Written by David MacKenzie, djm@gnu.ai.mit.edu.
Copyright (C) 91, 1995-2002 Free Software Foundation, Inc.
Modified for busybox based on coreutils v 5.0
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Copyright (C) 2003 Glenn McGrath
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Licensed under GPLv2 or later, see file LICENSE in this source tree.
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*/
//config:config FOLD
//config: bool "fold"
//config: default y
//config: help
//config: Wrap text to fit a specific width.
//applet:IF_FOLD(APPLET_NOEXEC(fold, fold, BB_DIR_USR_BIN, BB_SUID_DROP, fold))
//kbuild:lib-$(CONFIG_FOLD) += fold.o
//usage:#define fold_trivial_usage
//usage: "[-bs] [-w WIDTH] [FILE]..."
//usage:#define fold_full_usage "\n\n"
//usage: "Wrap input lines in each FILE (or stdin), writing to stdout\n"
//usage: "\n -b Count bytes rather than columns"
//usage: "\n -s Break at spaces"
//usage: "\n -w Use WIDTH columns instead of 80"
#include "libbb.h"
#include "unicode.h"
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/* This is a NOEXEC applet. Be very careful! */
/* Must match getopt32 call */
#define FLAG_COUNT_BYTES 1
#define FLAG_BREAK_SPACES 2
#define FLAG_WIDTH 4
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/* Assuming the current column is COLUMN, return the column that
printing C will move the cursor to.
The first column is 0. */
static int adjust_column(unsigned column, char c)
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{
if (option_mask32 & FLAG_COUNT_BYTES)
return ++column;
if (c == '\t')
return column + 8 - column % 8;
if (c == '\b') {
if ((int)--column < 0)
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column = 0;
}
else if (c == '\r')
column = 0;
else { /* just a printable char */
if (unicode_status != UNICODE_ON /* every byte is a new char */
|| (c & 0xc0) != 0x80 /* it isn't a 2nd+ byte of a Unicode char */
) {
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column++;
}
}
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return column;
}
/* Note that this function can write NULs, unlike fputs etc. */
static void write2stdout(const void *buf, unsigned size)
{
fwrite(buf, 1, size, stdout);
}
int fold_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int fold_main(int argc UNUSED_PARAM, char **argv)
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{
char *line_out = NULL;
const char *w_opt = "80";
unsigned width;
smallint exitcode = EXIT_SUCCESS;
init_unicode();
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if (ENABLE_INCLUDE_SUSv2) {
/* Turn any numeric options into -w options. */
int i;
for (i = 1; argv[i]; i++) {
const char *a = argv[i];
if (*a == '-') {
a++;
if (*a == '-' && !a[1]) /* "--" */
break;
if (isdigit(*a))
argv[i] = xasprintf("-w%s", a);
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}
}
}
getopt32(argv, "bsw:", &w_opt);
width = xatou_range(w_opt, 1, 10000);
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argv += optind;
if (!*argv)
*--argv = (char*)"-";
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do {
FILE *istream = fopen_or_warn_stdin(*argv);
int c;
unsigned column = 0; /* Screen column where next char will go */
unsigned offset_out = 0; /* Index in 'line_out' for next char */
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if (istream == NULL) {
exitcode = EXIT_FAILURE;
continue;
}
while ((c = getc(istream)) != EOF) {
/* We grow line_out in chunks of 0x1000 bytes */
if ((offset_out & 0xfff) == 0) {
line_out = xrealloc(line_out, offset_out + 0x1000);
}
rescan:
line_out[offset_out] = c;
if (c == '\n') {
write2stdout(line_out, offset_out + 1);
column = offset_out = 0;
continue;
}
column = adjust_column(column, c);
if (column <= width || offset_out == 0) {
/* offset_out == 0 case happens
* with small width (say, 1) and tabs.
* The very first tab already goes to column 8,
* but we must not wrap it */
offset_out++;
continue;
}
/* This character would make the line too long.
* Print the line plus a newline, and make this character
* start the next line */
if (option_mask32 & FLAG_BREAK_SPACES) {
unsigned i;
unsigned logical_end;
/* Look for the last blank. */
for (logical_end = offset_out - 1; (int)logical_end >= 0; logical_end--) {
if (!isblank(line_out[logical_end]))
continue;
/* Found a space or tab.
* Output up to and including it, and start a new line */
logical_end++;
/*line_out[logical_end] = '\n'; - NO! this nukes one buffered character */
write2stdout(line_out, logical_end);
putchar('\n');
/* Move the remainder to the beginning of the next line.
* The areas being copied here might overlap. */
memmove(line_out, line_out + logical_end, offset_out - logical_end);
offset_out -= logical_end;
for (column = i = 0; i < offset_out; i++) {
column = adjust_column(column, line_out[i]);
}
goto rescan;
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}
/* No blank found, wrap will split the overlong word */
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}
/* Output what we accumulated up to now, and start a new line */
line_out[offset_out] = '\n';
write2stdout(line_out, offset_out + 1);
column = offset_out = 0;
goto rescan;
} /* while (not EOF) */
if (offset_out) {
write2stdout(line_out, offset_out);
}
if (fclose_if_not_stdin(istream)) {
bb_simple_perror_msg(*argv);
exitcode = EXIT_FAILURE;
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}
} while (*++argv);
fflush_stdout_and_exit(exitcode);
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}