xref: /freebsd/usr.bin/col/col.c (revision 5b31cc94b10d4bb7109c6b27940a0fc76a44a331)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1990, 1993, 1994
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * Michael Rendell of the Memorial University of Newfoundland.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 #ifndef lint
36 static const char copyright[] =
37 "@(#) Copyright (c) 1990, 1993, 1994\n\
38 	The Regents of the University of California.  All rights reserved.\n";
39 #endif
40 
41 #if 0
42 #endif
43 
44 #include <sys/cdefs.h>
45 #include <sys/capsicum.h>
46 
47 #include <capsicum_helpers.h>
48 #include <err.h>
49 #include <errno.h>
50 #include <locale.h>
51 #include <stdio.h>
52 #include <stdlib.h>
53 #include <string.h>
54 #include <termios.h>
55 #include <unistd.h>
56 #include <wchar.h>
57 #include <wctype.h>
58 
59 #define	BS	'\b'		/* backspace */
60 #define	TAB	'\t'		/* tab */
61 #define	SPACE	' '		/* space */
62 #define	NL	'\n'		/* newline */
63 #define	CR	'\r'		/* carriage return */
64 #define	ESC	'\033'		/* escape */
65 #define	SI	'\017'		/* shift in to normal character set */
66 #define	SO	'\016'		/* shift out to alternate character set */
67 #define	VT	'\013'		/* vertical tab (aka reverse line feed) */
68 #define	RLF	'7'		/* ESC-7 reverse line feed */
69 #define	RHLF	'8'		/* ESC-8 reverse half-line feed */
70 #define	FHLF	'9'		/* ESC-9 forward half-line feed */
71 
72 /* build up at least this many lines before flushing them out */
73 #define	BUFFER_MARGIN		32
74 
75 typedef char CSET;
76 
77 typedef struct char_str {
78 #define	CS_NORMAL	1
79 #define	CS_ALTERNATE	2
80 	short		c_column;	/* column character is in */
81 	CSET		c_set;		/* character set (currently only 2) */
82 	wchar_t		c_char;		/* character in question */
83 	int		c_width;	/* character width */
84 } CHAR;
85 
86 typedef struct line_str LINE;
87 struct line_str {
88 	CHAR	*l_line;		/* characters on the line */
89 	LINE	*l_prev;		/* previous line */
90 	LINE	*l_next;		/* next line */
91 	int	l_lsize;		/* allocated sizeof l_line */
92 	int	l_line_len;		/* strlen(l_line) */
93 	int	l_needs_sort;		/* set if chars went in out of order */
94 	int	l_max_col;		/* max column in the line */
95 };
96 
97 static void	addto_lineno(int *, int);
98 static LINE	*alloc_line(void);
99 static void	dowarn(int);
100 static void	flush_line(LINE *);
101 static void	flush_lines(int);
102 static void	flush_blanks(void);
103 static void	free_line(LINE *);
104 static void	usage(void);
105 
106 static CSET	last_set;		/* char_set of last char printed */
107 static LINE	*lines;
108 static int	compress_spaces;	/* if doing space -> tab conversion */
109 static int	fine;			/* if `fine' resolution (half lines) */
110 static int	max_bufd_lines;		/* max # of half lines to keep in memory */
111 static int	nblank_lines;		/* # blanks after last flushed line */
112 static int	no_backspaces;		/* if not to output any backspaces */
113 static int	pass_unknown_seqs;	/* pass unknown control sequences */
114 
115 #define	PUTC(ch) \
116 	do {					\
117 		if (putwchar(ch) == WEOF)	\
118 			errx(1, "write error");	\
119 	} while (0)
120 
121 int
122 main(int argc, char **argv)
123 {
124 	wint_t ch;
125 	CHAR *c;
126 	CSET cur_set;			/* current character set */
127 	LINE *l;			/* current line */
128 	int extra_lines;		/* # of lines above first line */
129 	int cur_col;			/* current column */
130 	int cur_line;			/* line number of current position */
131 	int max_line;			/* max value of cur_line */
132 	int this_line;			/* line l points to */
133 	int nflushd_lines;		/* number of lines that were flushed */
134 	int adjust, opt, warned, width;
135 	const char *errstr;
136 
137 	(void)setlocale(LC_CTYPE, "");
138 
139 	if (caph_limit_stdio() == -1)
140 		err(1, "unable to limit stdio");
141 
142 	if (caph_enter() < 0)
143 		err(1, "unable to enter capability mode");
144 
145 	max_bufd_lines = 256;
146 	compress_spaces = 1;		/* compress spaces into tabs */
147 	while ((opt = getopt(argc, argv, "bfhl:px")) != -1)
148 		switch (opt) {
149 		case 'b':		/* do not output backspaces */
150 			no_backspaces = 1;
151 			break;
152 		case 'f':		/* allow half forward line feeds */
153 			fine = 1;
154 			break;
155 		case 'h':		/* compress spaces into tabs */
156 			compress_spaces = 1;
157 			break;
158 		case 'l':		/* buffered line count */
159 			max_bufd_lines = strtonum(optarg, 1,
160 			    (INT_MAX - BUFFER_MARGIN) / 2, &errstr) * 2;
161 			if (errstr != NULL)
162 				errx(1, "bad -l argument, %s: %s", errstr,
163 					optarg);
164 			break;
165 		case 'p':		/* pass unknown control sequences */
166 			pass_unknown_seqs = 1;
167 			break;
168 		case 'x':		/* do not compress spaces into tabs */
169 			compress_spaces = 0;
170 			break;
171 		case '?':
172 		default:
173 			usage();
174 		}
175 
176 	if (optind != argc)
177 		usage();
178 
179 	adjust = cur_col = extra_lines = warned = 0;
180 	cur_line = max_line = nflushd_lines = this_line = 0;
181 	cur_set = last_set = CS_NORMAL;
182 	lines = l = alloc_line();
183 
184 	while ((ch = getwchar()) != WEOF) {
185 		if (!iswgraph(ch)) {
186 			switch (ch) {
187 			case BS:		/* can't go back further */
188 				if (cur_col == 0)
189 					continue;
190 				--cur_col;
191 				continue;
192 			case CR:
193 				cur_col = 0;
194 				continue;
195 			case ESC:		/* just ignore EOF */
196 				switch(getwchar()) {
197 				/*
198 				 * In the input stream, accept both the
199 				 * XPG5 sequences ESC-digit and the
200 				 * traditional BSD sequences ESC-ctrl.
201 				 */
202 				case '\007':
203 					/* FALLTHROUGH */
204 				case RLF:
205 					addto_lineno(&cur_line, -2);
206 					break;
207 				case '\010':
208 					/* FALLTHROUGH */
209 				case RHLF:
210 					addto_lineno(&cur_line, -1);
211 					break;
212 				case '\011':
213 					/* FALLTHROUGH */
214 				case FHLF:
215 					addto_lineno(&cur_line, 1);
216 					if (cur_line > max_line)
217 						max_line = cur_line;
218 				}
219 				continue;
220 			case NL:
221 				addto_lineno(&cur_line, 2);
222 				if (cur_line > max_line)
223 					max_line = cur_line;
224 				cur_col = 0;
225 				continue;
226 			case SPACE:
227 				++cur_col;
228 				continue;
229 			case SI:
230 				cur_set = CS_NORMAL;
231 				continue;
232 			case SO:
233 				cur_set = CS_ALTERNATE;
234 				continue;
235 			case TAB:		/* adjust column */
236 				cur_col |= 7;
237 				++cur_col;
238 				continue;
239 			case VT:
240 				addto_lineno(&cur_line, -2);
241 				continue;
242 			}
243 			if (iswspace(ch)) {
244 				if ((width = wcwidth(ch)) > 0)
245 					cur_col += width;
246 				continue;
247 			}
248 			if (!pass_unknown_seqs)
249 				continue;
250 		}
251 
252 		/* Must stuff ch in a line - are we at the right one? */
253 		if (cur_line + adjust != this_line) {
254 			LINE *lnew;
255 
256 			/* round up to next line */
257 			adjust = !fine && (cur_line & 1);
258 
259 			if (cur_line + adjust < this_line) {
260 				while (cur_line + adjust < this_line &&
261 				    l->l_prev != NULL) {
262 					l = l->l_prev;
263 					this_line--;
264 				}
265 				if (cur_line + adjust < this_line) {
266 					if (nflushd_lines == 0) {
267 						/*
268 						 * Allow backup past first
269 						 * line if nothing has been
270 						 * flushed yet.
271 						 */
272 						while (cur_line + adjust
273 						    < this_line) {
274 							lnew = alloc_line();
275 							l->l_prev = lnew;
276 							lnew->l_next = l;
277 							l = lines = lnew;
278 							extra_lines++;
279 							this_line--;
280 						}
281 					} else {
282 						if (!warned++)
283 							dowarn(cur_line);
284 						cur_line = this_line - adjust;
285 					}
286 				}
287 			} else {
288 				/* may need to allocate here */
289 				while (cur_line + adjust > this_line) {
290 					if (l->l_next == NULL) {
291 						l->l_next = alloc_line();
292 						l->l_next->l_prev = l;
293 					}
294 					l = l->l_next;
295 					this_line++;
296 				}
297 			}
298 			if (this_line > nflushd_lines &&
299 			    this_line - nflushd_lines >=
300 			    max_bufd_lines + BUFFER_MARGIN) {
301 				if (extra_lines) {
302 					flush_lines(extra_lines);
303 					extra_lines = 0;
304 				}
305 				flush_lines(this_line - nflushd_lines -
306 				    max_bufd_lines);
307 				nflushd_lines = this_line - max_bufd_lines;
308 			}
309 		}
310 		/* grow line's buffer? */
311 		if (l->l_line_len + 1 >= l->l_lsize) {
312 			int need;
313 
314 			need = l->l_lsize ? l->l_lsize * 2 : 90;
315 			if ((l->l_line = realloc(l->l_line,
316 			    (unsigned)need * sizeof(CHAR))) == NULL)
317 				err(1, NULL);
318 			l->l_lsize = need;
319 		}
320 		c = &l->l_line[l->l_line_len++];
321 		c->c_char = ch;
322 		c->c_set = cur_set;
323 		c->c_column = cur_col;
324 		c->c_width = wcwidth(ch);
325 		/*
326 		 * If things are put in out of order, they will need sorting
327 		 * when it is flushed.
328 		 */
329 		if (cur_col < l->l_max_col)
330 			l->l_needs_sort = 1;
331 		else
332 			l->l_max_col = cur_col;
333 		if (c->c_width > 0)
334 			cur_col += c->c_width;
335 	}
336 	if (ferror(stdin))
337 		err(1, NULL);
338 	if (extra_lines) {
339 		/*
340 		 * Extra lines only exist if no lines have been flushed
341 		 * yet. This means that 'lines' must point to line zero
342 		 * after we flush the extra lines.
343 		 */
344 		flush_lines(extra_lines);
345 		l = lines;
346 		this_line = 0;
347 	}
348 
349 	/* goto the last line that had a character on it */
350 	for (; l->l_next; l = l->l_next)
351 		this_line++;
352 	flush_lines(this_line - nflushd_lines + 1);
353 
354 	/* make sure we leave things in a sane state */
355 	if (last_set != CS_NORMAL)
356 		PUTC(SI);
357 
358 	/* flush out the last few blank lines */
359 	if (max_line >= this_line)
360 		nblank_lines = max_line - this_line + (max_line & 1);
361 	if (nblank_lines == 0)
362 		/* end with a newline even if the source doesn't */
363 		nblank_lines = 2;
364 	flush_blanks();
365 	exit(0);
366 }
367 
368 /*
369  * Prints the first 'nflush' lines. Printed lines are freed.
370  * After this function returns, 'lines' points to the first
371  * of the remaining lines, and 'nblank_lines' will have the
372  * number of half line feeds between the final flushed line
373  * and the first remaining line.
374  */
375 static void
376 flush_lines(int nflush)
377 {
378 	LINE *l;
379 
380 	while (--nflush >= 0) {
381 		l = lines;
382 		lines = l->l_next;
383 		if (l->l_line) {
384 			flush_blanks();
385 			flush_line(l);
386 			free(l->l_line);
387 		}
388 		if (l->l_next)
389 			nblank_lines++;
390 		free_line(l);
391 	}
392 	if (lines)
393 		lines->l_prev = NULL;
394 }
395 
396 /*
397  * Print a number of newline/half newlines.
398  * nblank_lines is the number of half line feeds.
399  */
400 static void
401 flush_blanks(void)
402 {
403 	int half, i, nb;
404 
405 	half = 0;
406 	nb = nblank_lines;
407 	if (nb & 1) {
408 		if (fine)
409 			half = 1;
410 		else
411 			nb++;
412 	}
413 	nb /= 2;
414 	for (i = nb; --i >= 0;)
415 		PUTC('\n');
416 	if (half) {
417 		PUTC(ESC);
418 		PUTC(FHLF);
419 		if (!nb)
420 			PUTC('\r');
421 	}
422 	nblank_lines = 0;
423 }
424 
425 /*
426  * Write a line to stdout taking care of space to tab conversion (-h flag)
427  * and character set shifts.
428  */
429 static void
430 flush_line(LINE *l)
431 {
432 	CHAR *c, *endc;
433 	int i, j, nchars, last_col, save, this_col, tot;
434 
435 	last_col = 0;
436 	nchars = l->l_line_len;
437 
438 	if (l->l_needs_sort) {
439 		static CHAR *sorted;
440 		static int count_size, *count, sorted_size;
441 
442 		/*
443 		 * Do an O(n) sort on l->l_line by column being careful to
444 		 * preserve the order of characters in the same column.
445 		 */
446 		if (l->l_lsize > sorted_size) {
447 			sorted_size = l->l_lsize;
448 			if ((sorted = realloc(sorted,
449 			    (unsigned)sizeof(CHAR) * sorted_size)) == NULL)
450 				err(1, NULL);
451 		}
452 		if (l->l_max_col >= count_size) {
453 			count_size = l->l_max_col + 1;
454 			if ((count = realloc(count,
455 			    (unsigned)sizeof(int) * count_size)) == NULL)
456 				err(1, NULL);
457 		}
458 		memset(count, 0, sizeof(int) * l->l_max_col + 1);
459 		for (i = nchars, c = l->l_line; --i >= 0; c++)
460 			count[c->c_column]++;
461 
462 		/*
463 		 * calculate running total (shifted down by 1) to use as
464 		 * indices into new line.
465 		 */
466 		for (tot = 0, i = 0; i <= l->l_max_col; i++) {
467 			save = count[i];
468 			count[i] = tot;
469 			tot += save;
470 		}
471 
472 		for (i = nchars, c = l->l_line; --i >= 0; c++)
473 			sorted[count[c->c_column]++] = *c;
474 		c = sorted;
475 	} else
476 		c = l->l_line;
477 	while (nchars > 0) {
478 		this_col = c->c_column;
479 		endc = c;
480 		do {
481 			++endc;
482 		} while (--nchars > 0 && this_col == endc->c_column);
483 
484 		/* if -b only print last character */
485 		if (no_backspaces) {
486 			c = endc - 1;
487 			if (nchars > 0 &&
488 			    this_col + c->c_width > endc->c_column)
489 				continue;
490 		}
491 
492 		if (this_col > last_col) {
493 			int nspace = this_col - last_col;
494 
495 			if (compress_spaces && nspace > 1) {
496 				while (1) {
497 					int tab_col, tab_size;
498 
499 					tab_col = (last_col + 8) & ~7;
500 					if (tab_col > this_col)
501 						break;
502 					tab_size = tab_col - last_col;
503 					if (tab_size == 1)
504 						PUTC(' ');
505 					else
506 						PUTC('\t');
507 					nspace -= tab_size;
508 					last_col = tab_col;
509 				}
510 			}
511 			while (--nspace >= 0)
512 				PUTC(' ');
513 			last_col = this_col;
514 		}
515 
516 		for (;;) {
517 			if (c->c_set != last_set) {
518 				switch (c->c_set) {
519 				case CS_NORMAL:
520 					PUTC(SI);
521 					break;
522 				case CS_ALTERNATE:
523 					PUTC(SO);
524 				}
525 				last_set = c->c_set;
526 			}
527 			PUTC(c->c_char);
528 			if ((c + 1) < endc)
529 				for (j = 0; j < c->c_width; j++)
530 					PUTC('\b');
531 			if (++c >= endc)
532 				break;
533 		}
534 		last_col += (c - 1)->c_width;
535 	}
536 }
537 
538 /*
539  * Increment or decrement a line number, checking for overflow.
540  * Stop one below INT_MAX such that the adjust variable is safe.
541  */
542 void
543 addto_lineno(int *lno, int offset)
544 {
545 	if (offset > 0) {
546 		if (*lno >= INT_MAX - offset)
547 			errx(1, "too many lines");
548 	} else {
549 		if (*lno < INT_MIN - offset)
550 			errx(1, "too many reverse line feeds");
551 	}
552 	*lno += offset;
553 }
554 
555 #define	NALLOC 64
556 
557 static LINE *line_freelist;
558 
559 static LINE *
560 alloc_line(void)
561 {
562 	LINE *l;
563 	int i;
564 
565 	if (!line_freelist) {
566 		if ((l = realloc(NULL, sizeof(LINE) * NALLOC)) == NULL)
567 			err(1, NULL);
568 		line_freelist = l;
569 		for (i = 1; i < NALLOC; i++, l++)
570 			l->l_next = l + 1;
571 		l->l_next = NULL;
572 	}
573 	l = line_freelist;
574 	line_freelist = l->l_next;
575 
576 	memset(l, 0, sizeof(LINE));
577 	return (l);
578 }
579 
580 static void
581 free_line(LINE *l)
582 {
583 
584 	l->l_next = line_freelist;
585 	line_freelist = l;
586 }
587 
588 static void
589 usage(void)
590 {
591 
592 	(void)fprintf(stderr, "usage: col [-bfhpx] [-l nline]\n");
593 	exit(1);
594 }
595 
596 static void
597 dowarn(int line)
598 {
599 
600 	warnx("warning: can't back up %s",
601 		line < 0 ? "past first line" : "-- line already flushed");
602 }
603