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