xref: /freebsd/usr.bin/col/col.c (revision 8881d206f4e68b564c2c5f50fc717086fc3e827a)
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 #ifndef lint
43 static char sccsid[] = "@(#)col.c	8.5 (Berkeley) 5/4/95";
44 #endif
45 #endif
46 
47 #include <sys/cdefs.h>
48 __FBSDID("$FreeBSD$");
49 
50 #include <sys/capsicum.h>
51 
52 #include <capsicum_helpers.h>
53 #include <err.h>
54 #include <errno.h>
55 #include <locale.h>
56 #include <stdio.h>
57 #include <stdlib.h>
58 #include <string.h>
59 #include <termios.h>
60 #include <unistd.h>
61 #include <wchar.h>
62 #include <wctype.h>
63 
64 #define	BS	'\b'		/* backspace */
65 #define	TAB	'\t'		/* tab */
66 #define	SPACE	' '		/* space */
67 #define	NL	'\n'		/* newline */
68 #define	CR	'\r'		/* carriage return */
69 #define	ESC	'\033'		/* escape */
70 #define	SI	'\017'		/* shift in to normal character set */
71 #define	SO	'\016'		/* shift out to alternate character set */
72 #define	VT	'\013'		/* vertical tab (aka reverse line feed) */
73 #define	RLF	'7'		/* ESC-7 reverse line feed */
74 #define	RHLF	'8'		/* ESC-8 reverse half-line feed */
75 #define	FHLF	'9'		/* ESC-9 forward half-line feed */
76 
77 /* build up at least this many lines before flushing them out */
78 #define	BUFFER_MARGIN		32
79 
80 typedef char CSET;
81 
82 typedef struct char_str {
83 #define	CS_NORMAL	1
84 #define	CS_ALTERNATE	2
85 	short		c_column;	/* column character is in */
86 	CSET		c_set;		/* character set (currently only 2) */
87 	wchar_t		c_char;		/* character in question */
88 	int		c_width;	/* character width */
89 } CHAR;
90 
91 typedef struct line_str LINE;
92 struct line_str {
93 	CHAR	*l_line;		/* characters on the line */
94 	LINE	*l_prev;		/* previous line */
95 	LINE	*l_next;		/* next line */
96 	int	l_lsize;		/* allocated sizeof l_line */
97 	int	l_line_len;		/* strlen(l_line) */
98 	int	l_needs_sort;		/* set if chars went in out of order */
99 	int	l_max_col;		/* max column in the line */
100 };
101 
102 static void	addto_lineno(int *, int);
103 static LINE	*alloc_line(void);
104 static void	dowarn(int);
105 static void	flush_line(LINE *);
106 static void	flush_lines(int);
107 static void	flush_blanks(void);
108 static void	free_line(LINE *);
109 static void	usage(void);
110 
111 static CSET	last_set;		/* char_set of last char printed */
112 static LINE	*lines;
113 static int	compress_spaces;	/* if doing space -> tab conversion */
114 static int	fine;			/* if `fine' resolution (half lines) */
115 static int	max_bufd_lines;		/* max # of half lines to keep in memory */
116 static int	nblank_lines;		/* # blanks after last flushed line */
117 static int	no_backspaces;		/* if not to output any backspaces */
118 static int	pass_unknown_seqs;	/* pass unknown control sequences */
119 
120 #define	PUTC(ch) \
121 	do {					\
122 		if (putwchar(ch) == WEOF)	\
123 			errx(1, "write error");	\
124 	} while (0)
125 
126 int
127 main(int argc, char **argv)
128 {
129 	wint_t ch;
130 	CHAR *c;
131 	CSET cur_set;			/* current character set */
132 	LINE *l;			/* current line */
133 	int extra_lines;		/* # of lines above first line */
134 	int cur_col;			/* current column */
135 	int cur_line;			/* line number of current position */
136 	int max_line;			/* max value of cur_line */
137 	int this_line;			/* line l points to */
138 	int nflushd_lines;		/* number of lines that were flushed */
139 	int adjust, opt, warned, width;
140 	const char *errstr;
141 
142 	(void)setlocale(LC_CTYPE, "");
143 
144 	if (caph_limit_stdio() == -1)
145 		err(1, "unable to limit stdio");
146 
147 	if (caph_enter() < 0)
148 		err(1, "unable to enter capability mode");
149 
150 	max_bufd_lines = 256;
151 	compress_spaces = 1;		/* compress spaces into tabs */
152 	while ((opt = getopt(argc, argv, "bfhl:px")) != -1)
153 		switch (opt) {
154 		case 'b':		/* do not output backspaces */
155 			no_backspaces = 1;
156 			break;
157 		case 'f':		/* allow half forward line feeds */
158 			fine = 1;
159 			break;
160 		case 'h':		/* compress spaces into tabs */
161 			compress_spaces = 1;
162 			break;
163 		case 'l':		/* buffered line count */
164 			max_bufd_lines = strtonum(optarg, 1,
165 			    (INT_MAX - BUFFER_MARGIN) / 2, &errstr) * 2;
166 			if (errstr != NULL)
167 				errx(1, "bad -l argument, %s: %s", errstr,
168 					optarg);
169 			break;
170 		case 'p':		/* pass unknown control sequences */
171 			pass_unknown_seqs = 1;
172 			break;
173 		case 'x':		/* do not compress spaces into tabs */
174 			compress_spaces = 0;
175 			break;
176 		case '?':
177 		default:
178 			usage();
179 		}
180 
181 	if (optind != argc)
182 		usage();
183 
184 	adjust = cur_col = extra_lines = warned = 0;
185 	cur_line = max_line = nflushd_lines = this_line = 0;
186 	cur_set = last_set = CS_NORMAL;
187 	lines = l = alloc_line();
188 
189 	while ((ch = getwchar()) != WEOF) {
190 		if (!iswgraph(ch)) {
191 			switch (ch) {
192 			case BS:		/* can't go back further */
193 				if (cur_col == 0)
194 					continue;
195 				--cur_col;
196 				continue;
197 			case CR:
198 				cur_col = 0;
199 				continue;
200 			case ESC:		/* just ignore EOF */
201 				switch(getwchar()) {
202 				/*
203 				 * In the input stream, accept both the
204 				 * XPG5 sequences ESC-digit and the
205 				 * traditional BSD sequences ESC-ctrl.
206 				 */
207 				case '\007':
208 					/* FALLTHROUGH */
209 				case RLF:
210 					addto_lineno(&cur_line, -2);
211 					break;
212 				case '\010':
213 					/* FALLTHROUGH */
214 				case RHLF:
215 					addto_lineno(&cur_line, -1);
216 					break;
217 				case '\011':
218 					/* FALLTHROUGH */
219 				case FHLF:
220 					addto_lineno(&cur_line, 1);
221 					if (cur_line > max_line)
222 						max_line = cur_line;
223 				}
224 				continue;
225 			case NL:
226 				addto_lineno(&cur_line, 2);
227 				if (cur_line > max_line)
228 					max_line = cur_line;
229 				cur_col = 0;
230 				continue;
231 			case SPACE:
232 				++cur_col;
233 				continue;
234 			case SI:
235 				cur_set = CS_NORMAL;
236 				continue;
237 			case SO:
238 				cur_set = CS_ALTERNATE;
239 				continue;
240 			case TAB:		/* adjust column */
241 				cur_col |= 7;
242 				++cur_col;
243 				continue;
244 			case VT:
245 				addto_lineno(&cur_line, -2);
246 				continue;
247 			}
248 			if (iswspace(ch)) {
249 				if ((width = wcwidth(ch)) > 0)
250 					cur_col += width;
251 				continue;
252 			}
253 			if (!pass_unknown_seqs)
254 				continue;
255 		}
256 
257 		/* Must stuff ch in a line - are we at the right one? */
258 		if (cur_line + adjust != this_line) {
259 			LINE *lnew;
260 
261 			/* round up to next line */
262 			adjust = !fine && (cur_line & 1);
263 
264 			if (cur_line + adjust < this_line) {
265 				while (cur_line + adjust < this_line &&
266 				    l->l_prev != NULL) {
267 					l = l->l_prev;
268 					this_line--;
269 				}
270 				if (cur_line + adjust < this_line) {
271 					if (nflushd_lines == 0) {
272 						/*
273 						 * Allow backup past first
274 						 * line if nothing has been
275 						 * flushed yet.
276 						 */
277 						while (cur_line + adjust
278 						    < this_line) {
279 							lnew = alloc_line();
280 							l->l_prev = lnew;
281 							lnew->l_next = l;
282 							l = lines = lnew;
283 							extra_lines++;
284 							this_line--;
285 						}
286 					} else {
287 						if (!warned++)
288 							dowarn(cur_line);
289 						cur_line = this_line - adjust;
290 					}
291 				}
292 			} else {
293 				/* may need to allocate here */
294 				while (cur_line + adjust > this_line) {
295 					if (l->l_next == NULL) {
296 						l->l_next = alloc_line();
297 						l->l_next->l_prev = l;
298 					}
299 					l = l->l_next;
300 					this_line++;
301 				}
302 			}
303 			if (this_line > nflushd_lines &&
304 			    this_line - nflushd_lines >=
305 			    max_bufd_lines + BUFFER_MARGIN) {
306 				if (extra_lines) {
307 					flush_lines(extra_lines);
308 					extra_lines = 0;
309 				}
310 				flush_lines(this_line - nflushd_lines -
311 				    max_bufd_lines);
312 				nflushd_lines = this_line - max_bufd_lines;
313 			}
314 		}
315 		/* grow line's buffer? */
316 		if (l->l_line_len + 1 >= l->l_lsize) {
317 			int need;
318 
319 			need = l->l_lsize ? l->l_lsize * 2 : 90;
320 			if ((l->l_line = realloc(l->l_line,
321 			    (unsigned)need * sizeof(CHAR))) == NULL)
322 				err(1, NULL);
323 			l->l_lsize = need;
324 		}
325 		c = &l->l_line[l->l_line_len++];
326 		c->c_char = ch;
327 		c->c_set = cur_set;
328 		c->c_column = cur_col;
329 		c->c_width = wcwidth(ch);
330 		/*
331 		 * If things are put in out of order, they will need sorting
332 		 * when it is flushed.
333 		 */
334 		if (cur_col < l->l_max_col)
335 			l->l_needs_sort = 1;
336 		else
337 			l->l_max_col = cur_col;
338 		if (c->c_width > 0)
339 			cur_col += c->c_width;
340 	}
341 	if (ferror(stdin))
342 		err(1, NULL);
343 	if (extra_lines) {
344 		/*
345 		 * Extra lines only exist if no lines have been flushed
346 		 * yet. This means that 'lines' must point to line zero
347 		 * after we flush the extra lines.
348 		 */
349 		flush_lines(extra_lines);
350 		l = lines;
351 		this_line = 0;
352 	}
353 
354 	/* goto the last line that had a character on it */
355 	for (; l->l_next; l = l->l_next)
356 		this_line++;
357 	flush_lines(this_line - nflushd_lines + 1);
358 
359 	/* make sure we leave things in a sane state */
360 	if (last_set != CS_NORMAL)
361 		PUTC(SI);
362 
363 	/* flush out the last few blank lines */
364 	if (max_line >= this_line)
365 		nblank_lines = max_line - this_line + (max_line & 1);
366 	if (nblank_lines == 0)
367 		/* end with a newline even if the source doesn't */
368 		nblank_lines = 2;
369 	flush_blanks();
370 	exit(0);
371 }
372 
373 /*
374  * Prints the first 'nflush' lines. Printed lines are freed.
375  * After this function returns, 'lines' points to the first
376  * of the remaining lines, and 'nblank_lines' will have the
377  * number of half line feeds between the final flushed line
378  * and the first remaining line.
379  */
380 static void
381 flush_lines(int nflush)
382 {
383 	LINE *l;
384 
385 	while (--nflush >= 0) {
386 		l = lines;
387 		lines = l->l_next;
388 		if (l->l_line) {
389 			flush_blanks();
390 			flush_line(l);
391 			free(l->l_line);
392 		}
393 		if (l->l_next)
394 			nblank_lines++;
395 		free_line(l);
396 	}
397 	if (lines)
398 		lines->l_prev = NULL;
399 }
400 
401 /*
402  * Print a number of newline/half newlines.
403  * nblank_lines is the number of half line feeds.
404  */
405 static void
406 flush_blanks(void)
407 {
408 	int half, i, nb;
409 
410 	half = 0;
411 	nb = nblank_lines;
412 	if (nb & 1) {
413 		if (fine)
414 			half = 1;
415 		else
416 			nb++;
417 	}
418 	nb /= 2;
419 	for (i = nb; --i >= 0;)
420 		PUTC('\n');
421 	if (half) {
422 		PUTC(ESC);
423 		PUTC(FHLF);
424 		if (!nb)
425 			PUTC('\r');
426 	}
427 	nblank_lines = 0;
428 }
429 
430 /*
431  * Write a line to stdout taking care of space to tab conversion (-h flag)
432  * and character set shifts.
433  */
434 static void
435 flush_line(LINE *l)
436 {
437 	CHAR *c, *endc;
438 	int i, j, nchars, last_col, save, this_col, tot;
439 
440 	last_col = 0;
441 	nchars = l->l_line_len;
442 
443 	if (l->l_needs_sort) {
444 		static CHAR *sorted;
445 		static int count_size, *count, sorted_size;
446 
447 		/*
448 		 * Do an O(n) sort on l->l_line by column being careful to
449 		 * preserve the order of characters in the same column.
450 		 */
451 		if (l->l_lsize > sorted_size) {
452 			sorted_size = l->l_lsize;
453 			if ((sorted = realloc(sorted,
454 			    (unsigned)sizeof(CHAR) * sorted_size)) == NULL)
455 				err(1, NULL);
456 		}
457 		if (l->l_max_col >= count_size) {
458 			count_size = l->l_max_col + 1;
459 			if ((count = realloc(count,
460 			    (unsigned)sizeof(int) * count_size)) == NULL)
461 				err(1, NULL);
462 		}
463 		memset(count, 0, sizeof(int) * l->l_max_col + 1);
464 		for (i = nchars, c = l->l_line; --i >= 0; c++)
465 			count[c->c_column]++;
466 
467 		/*
468 		 * calculate running total (shifted down by 1) to use as
469 		 * indices into new line.
470 		 */
471 		for (tot = 0, i = 0; i <= l->l_max_col; i++) {
472 			save = count[i];
473 			count[i] = tot;
474 			tot += save;
475 		}
476 
477 		for (i = nchars, c = l->l_line; --i >= 0; c++)
478 			sorted[count[c->c_column]++] = *c;
479 		c = sorted;
480 	} else
481 		c = l->l_line;
482 	while (nchars > 0) {
483 		this_col = c->c_column;
484 		endc = c;
485 		do {
486 			++endc;
487 		} while (--nchars > 0 && this_col == endc->c_column);
488 
489 		/* if -b only print last character */
490 		if (no_backspaces) {
491 			c = endc - 1;
492 			if (nchars > 0 &&
493 			    this_col + c->c_width > endc->c_column)
494 				continue;
495 		}
496 
497 		if (this_col > last_col) {
498 			int nspace = this_col - last_col;
499 
500 			if (compress_spaces && nspace > 1) {
501 				while (1) {
502 					int tab_col, tab_size;
503 
504 					tab_col = (last_col + 8) & ~7;
505 					if (tab_col > this_col)
506 						break;
507 					tab_size = tab_col - last_col;
508 					if (tab_size == 1)
509 						PUTC(' ');
510 					else
511 						PUTC('\t');
512 					nspace -= tab_size;
513 					last_col = tab_col;
514 				}
515 			}
516 			while (--nspace >= 0)
517 				PUTC(' ');
518 			last_col = this_col;
519 		}
520 
521 		for (;;) {
522 			if (c->c_set != last_set) {
523 				switch (c->c_set) {
524 				case CS_NORMAL:
525 					PUTC(SI);
526 					break;
527 				case CS_ALTERNATE:
528 					PUTC(SO);
529 				}
530 				last_set = c->c_set;
531 			}
532 			PUTC(c->c_char);
533 			if ((c + 1) < endc)
534 				for (j = 0; j < c->c_width; j++)
535 					PUTC('\b');
536 			if (++c >= endc)
537 				break;
538 		}
539 		last_col += (c - 1)->c_width;
540 	}
541 }
542 
543 /*
544  * Increment or decrement a line number, checking for overflow.
545  * Stop one below INT_MAX such that the adjust variable is safe.
546  */
547 void
548 addto_lineno(int *lno, int offset)
549 {
550 	if (offset > 0) {
551 		if (*lno >= INT_MAX - offset)
552 			errx(1, "too many lines");
553 	} else {
554 		if (*lno < INT_MIN - offset)
555 			errx(1, "too many reverse line feeds");
556 	}
557 	*lno += offset;
558 }
559 
560 #define	NALLOC 64
561 
562 static LINE *line_freelist;
563 
564 static LINE *
565 alloc_line(void)
566 {
567 	LINE *l;
568 	int i;
569 
570 	if (!line_freelist) {
571 		if ((l = realloc(NULL, sizeof(LINE) * NALLOC)) == NULL)
572 			err(1, NULL);
573 		line_freelist = l;
574 		for (i = 1; i < NALLOC; i++, l++)
575 			l->l_next = l + 1;
576 		l->l_next = NULL;
577 	}
578 	l = line_freelist;
579 	line_freelist = l->l_next;
580 
581 	memset(l, 0, sizeof(LINE));
582 	return (l);
583 }
584 
585 static void
586 free_line(LINE *l)
587 {
588 
589 	l->l_next = line_freelist;
590 	line_freelist = l;
591 }
592 
593 static void
594 usage(void)
595 {
596 
597 	(void)fprintf(stderr, "usage: col [-bfhpx] [-l nline]\n");
598 	exit(1);
599 }
600 
601 static void
602 dowarn(int line)
603 {
604 
605 	warnx("warning: can't back up %s",
606 		line < 0 ? "past first line" : "-- line already flushed");
607 }
608