1/*	$OpenBSD: col.c,v 1.20 2022/12/04 23:50:47 cheloha Exp $	*/
2/*	$NetBSD: col.c,v 1.7 1995/09/02 05:48:50 jtc Exp $	*/
3
4/*-
5 * Copyright (c) 1990, 1993, 1994
6 *	The Regents of the University of California.  All rights reserved.
7 *
8 * This code is derived from software contributed to Berkeley by
9 * Michael Rendell of the Memorial University of Newfoundland.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 *    notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 *    notice, this list of conditions and the following disclaimer in the
18 *    documentation and/or other materials provided with the distribution.
19 * 3. Neither the name of the University nor the names of its contributors
20 *    may be used to endorse or promote products derived from this software
21 *    without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36#include <ctype.h>
37#include <err.h>
38#include <string.h>
39#include <stdio.h>
40#include <stdlib.h>
41#include <unistd.h>
42#include <limits.h>
43
44#define	BS	'\b'		/* backspace */
45#define	TAB	'\t'		/* tab */
46#define	SPACE	' '		/* space */
47#define	NL	'\n'		/* newline */
48#define	CR	'\r'		/* carriage return */
49#define	ESC	'\033'		/* escape */
50#define	SI	'\017'		/* shift in to normal character set */
51#define	SO	'\016'		/* shift out to alternate character set */
52#define	VT	'\013'		/* vertical tab (aka reverse line feed) */
53
54/* build up at least this many lines before flushing them out */
55#define	BUFFER_MARGIN		32
56
57typedef char CSET;
58
59typedef struct char_str {
60#define	CS_NORMAL	1
61#define	CS_ALTERNATE	2
62	size_t		c_column;	/* column character is in */
63	CSET		c_set;		/* character set (currently only 2) */
64	char		c_char;		/* character in question */
65} CHAR;
66
67typedef struct line_str LINE;
68struct line_str {
69	CHAR	*l_line;		/* characters on the line */
70	LINE	*l_prev;		/* previous line */
71	LINE	*l_next;		/* next line */
72	size_t	l_lsize;		/* allocated sizeof l_line */
73	size_t	l_line_len;		/* strlen(l_line) */
74	size_t	l_max_col;		/* max column in the line */
75	int	l_needs_sort;		/* set if chars went in out of order */
76};
77
78void	addto_lineno(int *, int);
79LINE   *alloc_line(void);
80void	dowarn(int);
81void	flush_line(LINE *);
82void	flush_lines(int);
83void	flush_blanks(void);
84void	free_line(LINE *);
85void	usage(void);
86void   *xreallocarray(void *, size_t, size_t);
87
88CSET	last_set;		/* char_set of last char printed */
89LINE   *lines;
90int	compress_spaces;	/* if doing space -> tab conversion */
91int	fine;			/* if `fine' resolution (half lines) */
92int	max_bufd_lines;		/* max # of half lines to keep in memory */
93int	nblank_lines;		/* # blanks after last flushed line */
94int	no_backspaces;		/* if not to output any backspaces */
95
96#define	PUTC(ch) \
97	if (putchar(ch) == EOF) \
98		err(1, "stdout");
99
100int
101main(int argc, char *argv[])
102{
103	int ch;
104	CHAR *c;
105	CSET cur_set;			/* current character set */
106	LINE *l;			/* current line */
107	int extra_lines;		/* # of lines above first line */
108	size_t cur_col;			/* current column */
109	int cur_line;			/* line number of current position */
110	int max_line;			/* max value of cur_line */
111	int this_line;			/* line l points to */
112	int nflushd_lines;		/* number of lines that were flushed */
113	int adjust, opt, warned;
114	const char *errstr;
115
116	if (pledge("stdio", NULL) == -1)
117		err(1, "pledge");
118
119	max_bufd_lines = 256;
120	compress_spaces = 1;		/* compress spaces into tabs */
121	while ((opt = getopt(argc, argv, "bfhl:x")) != -1)
122		switch (opt) {
123		case 'b':		/* do not output backspaces */
124			no_backspaces = 1;
125			break;
126		case 'f':		/* allow half forward line feeds */
127			fine = 1;
128			break;
129		case 'h':		/* compress spaces into tabs */
130			compress_spaces = 1;
131			break;
132		case 'l':		/* buffered line count */
133			max_bufd_lines = strtonum(optarg, 1,
134			    (INT_MAX - BUFFER_MARGIN) / 2, &errstr) * 2;
135			if (errstr != NULL)
136				errx(1, "bad -l argument, %s: %s", errstr,
137					optarg);
138			break;
139		case 'x':		/* do not compress spaces into tabs */
140			compress_spaces = 0;
141			break;
142		default:
143			usage();
144		}
145
146	if (optind != argc)
147		usage();
148
149	adjust = extra_lines = warned = 0;
150	cur_col = 0;
151	cur_line = max_line = nflushd_lines = this_line = 0;
152	cur_set = last_set = CS_NORMAL;
153	lines = l = alloc_line();
154
155	while ((ch = getchar()) != EOF) {
156		if (!isgraph(ch)) {
157			switch (ch) {
158			case BS:		/* can't go back further */
159				if (cur_col == 0)
160					continue;
161				--cur_col;
162				continue;
163			case CR:
164				cur_col = 0;
165				continue;
166			case ESC:		/* just ignore EOF */
167				/*
168				 * In the input stream, accept both the
169				 * XPG5 sequences ESC-digit and the
170				 * traditional BSD sequences ESC-ctrl.
171				 */
172				switch(getchar()) {
173				case '7':  /* reverse line feed */
174					/* FALLTHROUGH */
175				case '\007':
176					addto_lineno(&cur_line, -2);
177					break;
178				case '8':  /* reverse half-line feed */
179					/* FALLTHROUGH */
180				case '\010':
181					addto_lineno(&cur_line, -1);
182					break;
183				case '9':  /* forward half-line feed */
184					/* FALLTHROUGH */
185				case '\011':
186					addto_lineno(&cur_line, 1);
187					if (cur_line > max_line)
188						max_line = cur_line;
189				}
190				continue;
191			case NL:
192				addto_lineno(&cur_line, 2);
193				if (cur_line > max_line)
194					max_line = cur_line;
195				cur_col = 0;
196				continue;
197			case SPACE:
198				++cur_col;
199				continue;
200			case SI:
201				cur_set = CS_NORMAL;
202				continue;
203			case SO:
204				cur_set = CS_ALTERNATE;
205				continue;
206			case TAB:		/* adjust column */
207				cur_col |= 7;
208				++cur_col;
209				continue;
210			case VT:
211				addto_lineno(&cur_line, -2);
212				continue;
213			}
214			continue;
215		}
216
217		/* Must stuff ch in a line - are we at the right one? */
218		if (cur_line + adjust != this_line) {
219			LINE *lnew;
220
221			/* round up to next line */
222			adjust = !fine && (cur_line & 1);
223
224			if (cur_line + adjust < this_line) {
225				while (cur_line + adjust < this_line &&
226				    l->l_prev != NULL) {
227					l = l->l_prev;
228					this_line--;
229				}
230				if (cur_line + adjust < this_line) {
231					if (nflushd_lines == 0) {
232						/*
233						 * Allow backup past first
234						 * line if nothing has been
235						 * flushed yet.
236						 */
237						while (cur_line + adjust
238						    < this_line) {
239							lnew = alloc_line();
240							l->l_prev = lnew;
241							lnew->l_next = l;
242							l = lines = lnew;
243							extra_lines++;
244							this_line--;
245						}
246					} else {
247						if (!warned++)
248							dowarn(cur_line);
249						cur_line = this_line - adjust;
250					}
251				}
252			} else {
253				/* may need to allocate here */
254				while (cur_line + adjust > this_line) {
255					if (l->l_next == NULL) {
256						l->l_next = alloc_line();
257						l->l_next->l_prev = l;
258					}
259					l = l->l_next;
260					this_line++;
261				}
262			}
263			if (this_line > nflushd_lines &&
264			    this_line - nflushd_lines >=
265			    max_bufd_lines + BUFFER_MARGIN) {
266				if (extra_lines) {
267					flush_lines(extra_lines);
268					extra_lines = 0;
269				}
270				flush_lines(this_line - nflushd_lines -
271				    max_bufd_lines);
272				nflushd_lines = this_line - max_bufd_lines;
273			}
274		}
275		/* grow line's buffer? */
276		if (l->l_line_len + 1 >= l->l_lsize) {
277			size_t need;
278
279			need = l->l_lsize ? l->l_lsize : 45;
280			l->l_line = xreallocarray(l->l_line,
281			    need, 2 * sizeof(CHAR));
282			l->l_lsize = need * 2;
283		}
284		c = &l->l_line[l->l_line_len++];
285		c->c_char = ch;
286		c->c_set = cur_set;
287		c->c_column = cur_col;
288		/*
289		 * If things are put in out of order, they will need sorting
290		 * when it is flushed.
291		 */
292		if (cur_col < l->l_max_col)
293			l->l_needs_sort = 1;
294		else
295			l->l_max_col = cur_col;
296		cur_col++;
297	}
298	if (extra_lines)
299		flush_lines(extra_lines);
300
301	/* goto the last line that had a character on it */
302	for (; l->l_next; l = l->l_next)
303		this_line++;
304	flush_lines(this_line - nflushd_lines + 1);
305
306	/* make sure we leave things in a sane state */
307	if (last_set != CS_NORMAL)
308		PUTC(SI);
309
310	/* flush out the last few blank lines */
311	if (max_line > this_line)
312		nblank_lines = max_line - this_line;
313	if (max_line & 1)
314		nblank_lines++;
315	flush_blanks();
316	exit(0);
317}
318
319void
320flush_lines(int nflush)
321{
322	LINE *l;
323
324	while (--nflush >= 0) {
325		l = lines;
326		lines = l->l_next;
327		if (l->l_line) {
328			flush_blanks();
329			flush_line(l);
330		}
331		if (l->l_line || l->l_next)
332			nblank_lines++;
333		if (l->l_line)
334			(void)free((void *)l->l_line);
335		free_line(l);
336	}
337	if (lines)
338		lines->l_prev = NULL;
339}
340
341/*
342 * Print a number of newline/half newlines.  If fine flag is set, nblank_lines
343 * is the number of half line feeds, otherwise it is the number of whole line
344 * feeds.
345 */
346void
347flush_blanks(void)
348{
349	int half, i, nb;
350
351	half = 0;
352	nb = nblank_lines;
353	if (nb & 1) {
354		if (fine)
355			half = 1;
356		else
357			nb++;
358	}
359	nb /= 2;
360	for (i = nb; --i >= 0;)
361		PUTC('\n');
362	if (half) {
363		/*
364		 * In the output stream, always generate
365		 * escape sequences conforming to XPG5.
366		 */
367		PUTC(ESC);
368		PUTC('9');
369		if (!nb)
370			PUTC('\r');
371	}
372	nblank_lines = 0;
373}
374
375/*
376 * Write a line to stdout taking care of space to tab conversion (-h flag)
377 * and character set shifts.
378 */
379void
380flush_line(LINE *l)
381{
382	CHAR *c, *endc;
383	size_t nchars, last_col, this_col;
384
385	last_col = 0;
386	nchars = l->l_line_len;
387
388	if (l->l_needs_sort) {
389		static CHAR *sorted;
390		static size_t count_size, i, sorted_size;
391		static int *count, save, tot;
392
393		/*
394		 * Do an O(n) sort on l->l_line by column being careful to
395		 * preserve the order of characters in the same column.
396		 */
397		if (l->l_lsize > sorted_size) {
398			sorted_size = l->l_lsize;
399			sorted = xreallocarray(sorted,
400			    sorted_size, sizeof(CHAR));
401		}
402		if (l->l_max_col >= count_size) {
403			count_size = l->l_max_col + 1;
404			count = xreallocarray(count,
405			    count_size, sizeof(int));
406		}
407		memset(count, 0, sizeof(*count) * (l->l_max_col + 1));
408		for (i = nchars, c = l->l_line; i-- > 0; c++)
409			count[c->c_column]++;
410
411		/*
412		 * calculate running total (shifted down by 1) to use as
413		 * indices into new line.
414		 */
415		for (tot = 0, i = 0; i <= l->l_max_col; i++) {
416			save = count[i];
417			count[i] = tot;
418			tot += save;
419		}
420
421		for (i = nchars, c = l->l_line; i-- > 0; c++)
422			sorted[count[c->c_column]++] = *c;
423		c = sorted;
424	} else
425		c = l->l_line;
426	while (nchars > 0) {
427		this_col = c->c_column;
428		endc = c;
429		do {
430			++endc;
431		} while (--nchars > 0 && this_col == endc->c_column);
432
433		/* if -b only print last character */
434		if (no_backspaces)
435			c = endc - 1;
436
437		if (this_col > last_col) {
438			size_t nspace = this_col - last_col;
439
440			if (compress_spaces && nspace > 1) {
441				size_t ntabs;
442
443				ntabs = ((last_col % 8) + nspace) / 8;
444				if (ntabs) {
445					nspace -= (ntabs * 8) - (last_col % 8);
446					while (ntabs-- > 0)
447						PUTC('\t');
448				}
449			}
450			while (nspace-- > 0)
451				PUTC(' ');
452			last_col = this_col;
453		}
454		last_col++;
455
456		for (;;) {
457			if (c->c_set != last_set) {
458				switch (c->c_set) {
459				case CS_NORMAL:
460					PUTC(SI);
461					break;
462				case CS_ALTERNATE:
463					PUTC(SO);
464				}
465				last_set = c->c_set;
466			}
467			PUTC(c->c_char);
468			if (++c >= endc)
469				break;
470			PUTC('\b');
471		}
472	}
473}
474
475/*
476 * Increment or decrement a line number, checking for overflow.
477 * Stop one below INT_MAX such that the adjust variable is safe.
478 */
479void
480addto_lineno(int *lno, int offset)
481{
482	if (offset > 0) {
483		if (*lno >= INT_MAX - offset)
484			errx(1, "too many lines");
485	} else {
486		if (*lno < INT_MIN - offset)
487			errx(1, "too many reverse line feeds");
488	}
489	*lno += offset;
490}
491
492#define	NALLOC 64
493
494static LINE *line_freelist;
495
496LINE *
497alloc_line(void)
498{
499	LINE *l;
500	int i;
501
502	if (!line_freelist) {
503		l = xreallocarray(NULL, NALLOC, sizeof(LINE));
504		line_freelist = l;
505		for (i = 1; i < NALLOC; i++, l++)
506			l->l_next = l + 1;
507		l->l_next = NULL;
508	}
509	l = line_freelist;
510	line_freelist = l->l_next;
511
512	memset(l, 0, sizeof(LINE));
513	return (l);
514}
515
516void
517free_line(LINE *l)
518{
519
520	l->l_next = line_freelist;
521	line_freelist = l;
522}
523
524void *
525xreallocarray(void *p, size_t n, size_t size)
526{
527
528	if (!(p = reallocarray(p, n, size)))
529		err(1, "realloc failed");
530	return (p);
531}
532
533void
534usage(void)
535{
536	(void)fprintf(stderr, "usage: col [-bfhx] [-l num]\n");
537	exit(1);
538}
539
540void
541dowarn(int line)
542{
543
544	warnx("warning: can't back up %s",
545		line < 0 ? "past first line" : "-- line already flushed");
546}
547