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/* fold.c - fold text
*
* Copyright 2014 Samuel Holland <samuel@sholland.net>
*
* See http://pubs.opengroup.org/onlinepubs/9699919799/utilities/fold.html
USE_FOLD(NEWTOY(fold, "bsuw#", TOYFLAG_USR|TOYFLAG_BIN))
config FOLD
bool "fold"
default n
help
usage: fold [-bsu] [-w WIDTH] [FILE...]
Folds (wraps) or unfolds FILE or stdin by adding or removing newlines.
Default line width is 80 columns for folding and infinite for unfolding.
-b Fold based on bytes instead of columns
-s Fold/unfold at whitespace boundaries if possible
-u Unfold text (and refold if -w is given)
-w Set lines to WIDTH columns or bytes
*/
#define FOR_fold
#include "toys.h"
GLOBALS(
int width;
)
void do_fold(int fd, char *name)
{
char *buf;
int bufsz, pos, len = 0, maxlen, split;
if (toys.optflags & FLAG_w)
maxlen = TT.width;
else if (toys.optflags & FLAG_u)
maxlen = 0;
else
maxlen = 80;
while ((bufsz = read(fd, toybuf, sizeof(toybuf))) > 0) {
buf = toybuf;
pos = 0;
split = -1;
while (pos < bufsz) {
switch (buf[pos]) {
case '\n':
//print everything but the \n, then move on to the next buffer
if ((toys.optflags & FLAG_u) && buf[pos-1] != '\n'
&& buf[pos+1] != '\n') {
xwrite(1, buf, pos);
bufsz -= pos + 1;
buf += pos + 1;
pos = 0;
split = -1;
}
//reset len, FLAG_b or not; just print multiple lines at once
else len = 0;
break;
case '\b':
//len cannot be negative; not allowed to wrap after backspace
if (toys.optflags & FLAG_b) len++;
else if (len > 0) len--;
break;
case '\r':
//not allowed to wrap after carriage return
if (toys.optflags & FLAG_b) len++;
else len = 0;
break;
case '\t':
//round to 8, but we add one after falling through
//(because of whitespace, but it also takes care of FLAG_b)
if (!(toys.optflags & FLAG_b)) len = (len & -8) + 7;
case ' ':
split = pos;
default:
len++;
}
//we don't want to double up \n; not allowed to wrap before \b
if (maxlen > 0 && len >= maxlen && buf[pos+1] != '\n' && buf[pos+1] != '\b') {
if (!(toys.optflags & FLAG_s) || split < 0) split = pos;
xwrite(1, buf, split + 1);
xputc('\n');
bufsz -= split + 1;
buf += split + 1;
len = pos = 0;
split = -1;
} else {
pos++;
}
}
xwrite(1, buf, bufsz);
}
xputc('\n');
}
void fold_main(void)
{
loopfiles(toys.optargs, do_fold);
}
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