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 the GPL v2 or later, see the file LICENSE in this tarball.
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*/
#include "libbb.h"
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static unsigned long flags;
#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(int column, char c)
{
if (!(flags & FLAG_COUNT_BYTES)) {
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if (c == '\b') {
if (column > 0)
column--;
} else if (c == '\r')
column = 0;
else if (c == '\t')
column = column + 8 - column % 8;
else /* if (isprint (c)) */
column++;
} else
column++;
return column;
}
int fold_main(int argc, char **argv);
int fold_main(int argc, char **argv)
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{
char *line_out = NULL;
int allocated_out = 0;
char *w_opt;
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int width = 80;
int i;
int errs = 0;
if (ENABLE_INCLUDE_SUSv2) {
/* Turn any numeric options into -w options. */
for (i = 1; i < argc; i++) {
char const *a = argv[i];
if (*a++ == '-') {
if (*a == '-' && !a[1])
break;
if (isdigit(*a)) {
argv[i] = xasprintf("-w%s", a);
}
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}
}
}
flags = getopt32(argv, "bsw:", &w_opt);
if (flags & FLAG_WIDTH)
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width = xatoul_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;
int column = 0; /* Screen column where next char will go. */
int offset_out = 0; /* Index in `line_out' for next char. */
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if (istream == NULL) {
errs |= EXIT_FAILURE;
continue;
}
while ((c = getc(istream)) != EOF) {
if (offset_out + 1 >= allocated_out) {
allocated_out += 1024;
line_out = xrealloc(line_out, allocated_out);
}
if (c == '\n') {
line_out[offset_out++] = c;
fwrite(line_out, sizeof(char), (size_t) offset_out, stdout);
column = offset_out = 0;
continue;
}
rescan:
column = adjust_column(column, c);
if (column > width) {
/* This character would make the line too long.
Print the line plus a newline, and make this character
start the next line. */
if (flags & FLAG_BREAK_SPACES) {
/* Look for the last blank. */
int logical_end;
for (logical_end = offset_out - 1; logical_end >= 0; logical_end--) {
if (isblank(line_out[logical_end])) {
break;
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}
}
if (logical_end >= 0) {
/* Found a blank. Don't output the part after it. */
logical_end++;
fwrite(line_out, sizeof(char), (size_t) logical_end, stdout);
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]);
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}
goto rescan;
}
} else {
if (offset_out == 0) {
line_out[offset_out++] = c;
continue;
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}
}
line_out[offset_out++] = '\n';
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fwrite(line_out, sizeof(char), (size_t) offset_out, stdout);
column = offset_out = 0;
goto rescan;
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}
line_out[offset_out++] = c;
}
if (offset_out) {
fwrite(line_out, sizeof(char), (size_t) offset_out, stdout);
}
if (ferror(istream) || fclose_if_not_stdin(istream)) {
bb_perror_msg("%s", *argv); /* Avoid multibyte problems. */
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errs |= EXIT_FAILURE;
}
} while (*++argv);
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fflush_stdout_and_exit(errs);
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}