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In the tbl(7) layout parser, use the roff(7) numerical expression parser
to support arithmetic operations in column width modifiers.

Documentation authors ought to focus on semantic markup and avoid trying
to manipulate presentational details.  Consequently, using tbl(7) is
discouraged in the first place, using column width modifiers even more
so, and complicating them by performing arithmetics yet more so.

However, the madhouse called DocBook relies on this feature.
For example, DocBook XSL version 1.79.2 generates man(7)+tbl(7) code
that abuses arithmetics in column width modifiers to format things
as simple and mundane as numbered lists, resulting in atrocious layout
that is very hard to read.  Last year, tb@ reported git-reset(1)
as an example of an affected manual page.

Properly parsing the width in the tbl(7) parser allows removal of some
incomplete ad-hoc parsing from the tbl(7) formatter, where it didn't
really belong.

/*	$Id: tbl.c,v 1.47 2025/01/05 18:14:39 schwarze Exp $ */
/*
 * Copyright (c) 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
 * Copyright (c) 2011, 2015 Ingo Schwarze <schwarze@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
#include "config.h"

#include <sys/types.h>

#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#include "mandoc_aux.h"
#include "mandoc.h"
#include "tbl.h"
#include "libmandoc.h"
#include "tbl_parse.h"
#include "tbl_int.h"


void
tbl_read(struct tbl_node *tbl, int ln, const char *p, int pos)
{
	const char	*cp;
	int		 active;

	/*
	 * In the options section, proceed to the layout section
	 * after a semicolon, or right away if there is no semicolon.
	 * Ignore semicolons in arguments.
	 */

	if (tbl->part == TBL_PART_OPTS) {
		tbl->part = TBL_PART_LAYOUT;
		active = 1;
		for (cp = p + pos; *cp != '\0'; cp++) {
			switch (*cp) {
			case '(':
				active = 0;
				continue;
			case ')':
				active = 1;
				continue;
			case ';':
				if (active)
					break;
				continue;
			default:
				continue;
			}
			break;
		}
		if (*cp == ';') {
			tbl_option(tbl, ln, p, &pos);
			if (p[pos] == '\0')
				return;
		}
	}

	/* Process the other section types.  */

	switch (tbl->part) {
	case TBL_PART_LAYOUT:
		tbl_layout(tbl, ln, p, pos);
		break;
	case TBL_PART_CDATA:
		tbl_cdata(tbl, ln, p, pos);
		break;
	default:
		tbl_data(tbl, ln, p, pos);
		break;
	}
}

struct tbl_node *
tbl_alloc(int pos, int line, struct tbl_node *last_tbl)
{
	struct tbl_node	*tbl;

	tbl = mandoc_calloc(1, sizeof(*tbl));
	if (last_tbl != NULL)
		last_tbl->next = tbl;
	tbl->line = line;
	tbl->pos = pos;
	tbl->part = TBL_PART_OPTS;
	tbl->opts.tab = '\t';
	tbl->opts.decimal = '.';
	return tbl;
}

void
tbl_free(struct tbl_node *tbl)
{
	struct tbl_node	*old_tbl;
	struct tbl_row	*rp;
	struct tbl_cell	*cp;
	struct tbl_span	*sp;
	struct tbl_dat	*dp;

	while (tbl != NULL) {
		while ((rp = tbl->first_row) != NULL) {
			tbl->first_row = rp->next;
			while (rp->first != NULL) {
				cp = rp->first;
				rp->first = cp->next;
				free(cp);
			}
			free(rp);
		}
		while ((sp = tbl->first_span) != NULL) {
			tbl->first_span = sp->next;
			while (sp->first != NULL) {
				dp = sp->first;
				sp->first = dp->next;
				free(dp->string);
				free(dp);
			}
			free(sp);
		}
		old_tbl = tbl;
		tbl = tbl->next;
		free(old_tbl);
	}
}

void
tbl_restart(int line, int pos, struct tbl_node *tbl)
{
	if (tbl->part == TBL_PART_CDATA)
		mandoc_msg(MANDOCERR_TBLDATA_BLK, line, pos, "T&");

	tbl->part = TBL_PART_LAYOUT;
	tbl->line = line;
	tbl->pos = pos;
}

struct tbl_span *
tbl_span(struct tbl_node *tbl)
{
	struct tbl_span	 *span;

	span = tbl->current_span ? tbl->current_span->next
				 : tbl->first_span;
	if (span != NULL)
		tbl->current_span = span;
	return span;
}

int
tbl_end(struct tbl_node *tbl, int still_open)
{
	struct tbl_span *sp;

	if (still_open)
		mandoc_msg(MANDOCERR_BLK_NOEND, tbl->line, tbl->pos, "TS");
	else if (tbl->part == TBL_PART_CDATA)
		mandoc_msg(MANDOCERR_TBLDATA_BLK, tbl->line, tbl->pos, "TE");

	sp = tbl->first_span;
	while (sp != NULL && sp->first == NULL)
		sp = sp->next;
	if (sp == NULL) {
		mandoc_msg(MANDOCERR_TBLDATA_NONE, tbl->line, tbl->pos, NULL);
		return 0;
	}
	return 1;
}