xref: /illumos-gate/usr/src/cmd/mandoc/term.c (revision f67cf39ba88ad7c4bee81445cc7a7468e0289f01)
1 /*	$Id: term.c,v 1.259 2017/01/08 18:16:58 schwarze Exp $ */
2 /*
3  * Copyright (c) 2008, 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
4  * Copyright (c) 2010-2017 Ingo Schwarze <schwarze@openbsd.org>
5  *
6  * Permission to use, copy, modify, and distribute this software for any
7  * purpose with or without fee is hereby granted, provided that the above
8  * copyright notice and this permission notice appear in all copies.
9  *
10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHORS DISCLAIM ALL WARRANTIES
11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR
13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17  */
18 #include "config.h"
19 
20 #include <sys/types.h>
21 
22 #include <assert.h>
23 #include <ctype.h>
24 #include <stdio.h>
25 #include <stdlib.h>
26 #include <string.h>
27 
28 #include "mandoc.h"
29 #include "mandoc_aux.h"
30 #include "out.h"
31 #include "term.h"
32 #include "main.h"
33 
34 static	size_t		 cond_width(const struct termp *, int, int *);
35 static	void		 adjbuf(struct termp *p, size_t);
36 static	void		 bufferc(struct termp *, char);
37 static	void		 encode(struct termp *, const char *, size_t);
38 static	void		 encode1(struct termp *, int);
39 
40 
41 void
42 term_free(struct termp *p)
43 {
44 
45 	free(p->buf);
46 	free(p->fontq);
47 	free(p);
48 }
49 
50 void
51 term_begin(struct termp *p, term_margin head,
52 		term_margin foot, const struct roff_meta *arg)
53 {
54 
55 	p->headf = head;
56 	p->footf = foot;
57 	p->argf = arg;
58 	(*p->begin)(p);
59 }
60 
61 void
62 term_end(struct termp *p)
63 {
64 
65 	(*p->end)(p);
66 }
67 
68 /*
69  * Flush a chunk of text.  By default, break the output line each time
70  * the right margin is reached, and continue output on the next line
71  * at the same offset as the chunk itself.  By default, also break the
72  * output line at the end of the chunk.
73  * The following flags may be specified:
74  *
75  *  - TERMP_NOBREAK: Do not break the output line at the right margin,
76  *    but only at the max right margin.  Also, do not break the output
77  *    line at the end of the chunk, such that the next call can pad to
78  *    the next column.  However, if less than p->trailspace blanks,
79  *    which can be 0, 1, or 2, remain to the right margin, the line
80  *    will be broken.
81  *  - TERMP_BRTRSP: Consider trailing whitespace significant
82  *    when deciding whether the chunk fits or not.
83  *  - TERMP_BRIND: If the chunk does not fit and the output line has
84  *    to be broken, start the next line at the right margin instead
85  *    of at the offset.  Used together with TERMP_NOBREAK for the tags
86  *    in various kinds of tagged lists.
87  *  - TERMP_DANGLE: Do not break the output line at the right margin,
88  *    append the next chunk after it even if this one is too long.
89  *    To be used together with TERMP_NOBREAK.
90  *  - TERMP_HANG: Like TERMP_DANGLE, and also suppress padding before
91  *    the next chunk if this column is not full.
92  */
93 void
94 term_flushln(struct termp *p)
95 {
96 	size_t		 i;     /* current input position in p->buf */
97 	int		 ntab;	/* number of tabs to prepend */
98 	size_t		 vis;   /* current visual position on output */
99 	size_t		 vbl;   /* number of blanks to prepend to output */
100 	size_t		 vend;	/* end of word visual position on output */
101 	size_t		 bp;    /* visual right border position */
102 	size_t		 dv;    /* temporary for visual pos calculations */
103 	size_t		 j;     /* temporary loop index for p->buf */
104 	size_t		 jhy;	/* last hyph before overflow w/r/t j */
105 	size_t		 maxvis; /* output position of visible boundary */
106 
107 	/*
108 	 * First, establish the maximum columns of "visible" content.
109 	 * This is usually the difference between the right-margin and
110 	 * an indentation, but can be, for tagged lists or columns, a
111 	 * small set of values.
112 	 *
113 	 * The following unsigned-signed subtractions look strange,
114 	 * but they are actually correct.  If the int p->overstep
115 	 * is negative, it gets sign extended.  Subtracting that
116 	 * very large size_t effectively adds a small number to dv.
117 	 */
118 	dv = p->rmargin > p->offset ? p->rmargin - p->offset : 0;
119 	maxvis = (int)dv > p->overstep ? dv - (size_t)p->overstep : 0;
120 
121 	if (p->flags & TERMP_NOBREAK) {
122 		dv = p->maxrmargin > p->offset ?
123 		     p->maxrmargin - p->offset : 0;
124 		bp = (int)dv > p->overstep ?
125 		     dv - (size_t)p->overstep : 0;
126 	} else
127 		bp = maxvis;
128 
129 	/*
130 	 * Calculate the required amount of padding.
131 	 */
132 	vbl = p->offset + p->overstep > p->viscol ?
133 	      p->offset + p->overstep - p->viscol : 0;
134 
135 	vis = vend = 0;
136 	i = 0;
137 
138 	while (i < p->col) {
139 		/*
140 		 * Handle literal tab characters: collapse all
141 		 * subsequent tabs into a single huge set of spaces.
142 		 */
143 		ntab = 0;
144 		while (i < p->col && '\t' == p->buf[i]) {
145 			vend = (vis / p->tabwidth + 1) * p->tabwidth;
146 			vbl += vend - vis;
147 			vis = vend;
148 			ntab++;
149 			i++;
150 		}
151 
152 		/*
153 		 * Count up visible word characters.  Control sequences
154 		 * (starting with the CSI) aren't counted.  A space
155 		 * generates a non-printing word, which is valid (the
156 		 * space is printed according to regular spacing rules).
157 		 */
158 
159 		for (j = i, jhy = 0; j < p->col; j++) {
160 			if (' ' == p->buf[j] || '\t' == p->buf[j])
161 				break;
162 
163 			/* Back over the last printed character. */
164 			if (8 == p->buf[j]) {
165 				assert(j);
166 				vend -= (*p->width)(p, p->buf[j - 1]);
167 				continue;
168 			}
169 
170 			/* Regular word. */
171 			/* Break at the hyphen point if we overrun. */
172 			if (vend > vis && vend < bp &&
173 			    (ASCII_HYPH == p->buf[j] ||
174 			     ASCII_BREAK == p->buf[j]))
175 				jhy = j;
176 
177 			/*
178 			 * Hyphenation now decided, put back a real
179 			 * hyphen such that we get the correct width.
180 			 */
181 			if (ASCII_HYPH == p->buf[j])
182 				p->buf[j] = '-';
183 
184 			vend += (*p->width)(p, p->buf[j]);
185 		}
186 
187 		/*
188 		 * Find out whether we would exceed the right margin.
189 		 * If so, break to the next line.
190 		 */
191 		if (vend > bp && 0 == jhy && vis > 0) {
192 			vend -= vis;
193 			(*p->endline)(p);
194 			p->viscol = 0;
195 			if (TERMP_BRIND & p->flags) {
196 				vbl = p->rmargin;
197 				vend += p->rmargin;
198 				vend -= p->offset;
199 			} else
200 				vbl = p->offset;
201 
202 			/* use pending tabs on the new line */
203 
204 			if (0 < ntab)
205 				vbl += ntab * p->tabwidth;
206 
207 			/*
208 			 * Remove the p->overstep width.
209 			 * Again, if p->overstep is negative,
210 			 * sign extension does the right thing.
211 			 */
212 
213 			bp += (size_t)p->overstep;
214 			p->overstep = 0;
215 		}
216 
217 		/* Write out the [remaining] word. */
218 		for ( ; i < p->col; i++) {
219 			if (vend > bp && jhy > 0 && i > jhy)
220 				break;
221 			if ('\t' == p->buf[i])
222 				break;
223 			if (' ' == p->buf[i]) {
224 				j = i;
225 				while (i < p->col && ' ' == p->buf[i])
226 					i++;
227 				dv = (i - j) * (*p->width)(p, ' ');
228 				vbl += dv;
229 				vend += dv;
230 				break;
231 			}
232 			if (ASCII_NBRSP == p->buf[i]) {
233 				vbl += (*p->width)(p, ' ');
234 				continue;
235 			}
236 			if (ASCII_BREAK == p->buf[i])
237 				continue;
238 
239 			/*
240 			 * Now we definitely know there will be
241 			 * printable characters to output,
242 			 * so write preceding white space now.
243 			 */
244 			if (vbl) {
245 				(*p->advance)(p, vbl);
246 				p->viscol += vbl;
247 				vbl = 0;
248 			}
249 
250 			(*p->letter)(p, p->buf[i]);
251 			if (8 == p->buf[i])
252 				p->viscol -= (*p->width)(p, p->buf[i-1]);
253 			else
254 				p->viscol += (*p->width)(p, p->buf[i]);
255 		}
256 		vis = vend;
257 	}
258 
259 	/*
260 	 * If there was trailing white space, it was not printed;
261 	 * so reset the cursor position accordingly.
262 	 */
263 	if (vis > vbl)
264 		vis -= vbl;
265 	else
266 		vis = 0;
267 
268 	p->col = 0;
269 	p->overstep = 0;
270 	p->flags &= ~(TERMP_BACKAFTER | TERMP_BACKBEFORE);
271 
272 	if ( ! (TERMP_NOBREAK & p->flags)) {
273 		p->viscol = 0;
274 		(*p->endline)(p);
275 		return;
276 	}
277 
278 	if (TERMP_HANG & p->flags) {
279 		p->overstep += (int)(p->offset + vis - p->rmargin +
280 		    p->trailspace * (*p->width)(p, ' '));
281 
282 		/*
283 		 * If we have overstepped the margin, temporarily move
284 		 * it to the right and flag the rest of the line to be
285 		 * shorter.
286 		 * If there is a request to keep the columns together,
287 		 * allow negative overstep when the column is not full.
288 		 */
289 		if (p->trailspace && p->overstep < 0)
290 			p->overstep = 0;
291 		return;
292 
293 	} else if (TERMP_DANGLE & p->flags)
294 		return;
295 
296 	/* Trailing whitespace is significant in some columns. */
297 	if (vis && vbl && (TERMP_BRTRSP & p->flags))
298 		vis += vbl;
299 
300 	/* If the column was overrun, break the line. */
301 	if (maxvis < vis + p->trailspace * (*p->width)(p, ' ')) {
302 		(*p->endline)(p);
303 		p->viscol = 0;
304 	}
305 }
306 
307 /*
308  * A newline only breaks an existing line; it won't assert vertical
309  * space.  All data in the output buffer is flushed prior to the newline
310  * assertion.
311  */
312 void
313 term_newln(struct termp *p)
314 {
315 
316 	p->flags |= TERMP_NOSPACE;
317 	if (p->col || p->viscol)
318 		term_flushln(p);
319 }
320 
321 /*
322  * Asserts a vertical space (a full, empty line-break between lines).
323  * Note that if used twice, this will cause two blank spaces and so on.
324  * All data in the output buffer is flushed prior to the newline
325  * assertion.
326  */
327 void
328 term_vspace(struct termp *p)
329 {
330 
331 	term_newln(p);
332 	p->viscol = 0;
333 	if (0 < p->skipvsp)
334 		p->skipvsp--;
335 	else
336 		(*p->endline)(p);
337 }
338 
339 /* Swap current and previous font; for \fP and .ft P */
340 void
341 term_fontlast(struct termp *p)
342 {
343 	enum termfont	 f;
344 
345 	f = p->fontl;
346 	p->fontl = p->fontq[p->fonti];
347 	p->fontq[p->fonti] = f;
348 }
349 
350 /* Set font, save current, discard previous; for \f, .ft, .B etc. */
351 void
352 term_fontrepl(struct termp *p, enum termfont f)
353 {
354 
355 	p->fontl = p->fontq[p->fonti];
356 	p->fontq[p->fonti] = f;
357 }
358 
359 /* Set font, save previous. */
360 void
361 term_fontpush(struct termp *p, enum termfont f)
362 {
363 
364 	p->fontl = p->fontq[p->fonti];
365 	if (++p->fonti == p->fontsz) {
366 		p->fontsz += 8;
367 		p->fontq = mandoc_reallocarray(p->fontq,
368 		    p->fontsz, sizeof(*p->fontq));
369 	}
370 	p->fontq[p->fonti] = f;
371 }
372 
373 /* Flush to make the saved pointer current again. */
374 void
375 term_fontpopq(struct termp *p, int i)
376 {
377 
378 	assert(i >= 0);
379 	if (p->fonti > i)
380 		p->fonti = i;
381 }
382 
383 /* Pop one font off the stack. */
384 void
385 term_fontpop(struct termp *p)
386 {
387 
388 	assert(p->fonti);
389 	p->fonti--;
390 }
391 
392 /*
393  * Handle pwords, partial words, which may be either a single word or a
394  * phrase that cannot be broken down (such as a literal string).  This
395  * handles word styling.
396  */
397 void
398 term_word(struct termp *p, const char *word)
399 {
400 	const char	 nbrsp[2] = { ASCII_NBRSP, 0 };
401 	const char	*seq, *cp;
402 	int		 sz, uc;
403 	size_t		 ssz;
404 	enum mandoc_esc	 esc;
405 
406 	if ( ! (TERMP_NOSPACE & p->flags)) {
407 		if ( ! (TERMP_KEEP & p->flags)) {
408 			bufferc(p, ' ');
409 			if (TERMP_SENTENCE & p->flags)
410 				bufferc(p, ' ');
411 		} else
412 			bufferc(p, ASCII_NBRSP);
413 	}
414 	if (TERMP_PREKEEP & p->flags)
415 		p->flags |= TERMP_KEEP;
416 
417 	if ( ! (p->flags & TERMP_NONOSPACE))
418 		p->flags &= ~TERMP_NOSPACE;
419 	else
420 		p->flags |= TERMP_NOSPACE;
421 
422 	p->flags &= ~(TERMP_SENTENCE | TERMP_NONEWLINE);
423 	p->skipvsp = 0;
424 
425 	while ('\0' != *word) {
426 		if ('\\' != *word) {
427 			if (TERMP_NBRWORD & p->flags) {
428 				if (' ' == *word) {
429 					encode(p, nbrsp, 1);
430 					word++;
431 					continue;
432 				}
433 				ssz = strcspn(word, "\\ ");
434 			} else
435 				ssz = strcspn(word, "\\");
436 			encode(p, word, ssz);
437 			word += (int)ssz;
438 			continue;
439 		}
440 
441 		word++;
442 		esc = mandoc_escape(&word, &seq, &sz);
443 		if (ESCAPE_ERROR == esc)
444 			continue;
445 
446 		switch (esc) {
447 		case ESCAPE_UNICODE:
448 			uc = mchars_num2uc(seq + 1, sz - 1);
449 			break;
450 		case ESCAPE_NUMBERED:
451 			uc = mchars_num2char(seq, sz);
452 			if (uc < 0)
453 				continue;
454 			break;
455 		case ESCAPE_SPECIAL:
456 			if (p->enc == TERMENC_ASCII) {
457 				cp = mchars_spec2str(seq, sz, &ssz);
458 				if (cp != NULL)
459 					encode(p, cp, ssz);
460 			} else {
461 				uc = mchars_spec2cp(seq, sz);
462 				if (uc > 0)
463 					encode1(p, uc);
464 			}
465 			continue;
466 		case ESCAPE_FONTBOLD:
467 			term_fontrepl(p, TERMFONT_BOLD);
468 			continue;
469 		case ESCAPE_FONTITALIC:
470 			term_fontrepl(p, TERMFONT_UNDER);
471 			continue;
472 		case ESCAPE_FONTBI:
473 			term_fontrepl(p, TERMFONT_BI);
474 			continue;
475 		case ESCAPE_FONT:
476 		case ESCAPE_FONTROMAN:
477 			term_fontrepl(p, TERMFONT_NONE);
478 			continue;
479 		case ESCAPE_FONTPREV:
480 			term_fontlast(p);
481 			continue;
482 		case ESCAPE_NOSPACE:
483 			if (p->flags & TERMP_BACKAFTER)
484 				p->flags &= ~TERMP_BACKAFTER;
485 			else if (*word == '\0')
486 				p->flags |= (TERMP_NOSPACE | TERMP_NONEWLINE);
487 			continue;
488 		case ESCAPE_SKIPCHAR:
489 			p->flags |= TERMP_BACKAFTER;
490 			continue;
491 		case ESCAPE_OVERSTRIKE:
492 			cp = seq + sz;
493 			while (seq < cp) {
494 				if (*seq == '\\') {
495 					mandoc_escape(&seq, NULL, NULL);
496 					continue;
497 				}
498 				encode1(p, *seq++);
499 				if (seq < cp) {
500 					if (p->flags & TERMP_BACKBEFORE)
501 						p->flags |= TERMP_BACKAFTER;
502 					else
503 						p->flags |= TERMP_BACKBEFORE;
504 				}
505 			}
506 			/* Trim trailing backspace/blank pair. */
507 			if (p->col > 2 &&
508 			    (p->buf[p->col - 1] == ' ' ||
509 			     p->buf[p->col - 1] == '\t'))
510 				p->col -= 2;
511 			continue;
512 		default:
513 			continue;
514 		}
515 
516 		/*
517 		 * Common handling for Unicode and numbered
518 		 * character escape sequences.
519 		 */
520 
521 		if (p->enc == TERMENC_ASCII) {
522 			cp = ascii_uc2str(uc);
523 			encode(p, cp, strlen(cp));
524 		} else {
525 			if ((uc < 0x20 && uc != 0x09) ||
526 			    (uc > 0x7E && uc < 0xA0))
527 				uc = 0xFFFD;
528 			encode1(p, uc);
529 		}
530 	}
531 	p->flags &= ~TERMP_NBRWORD;
532 }
533 
534 static void
535 adjbuf(struct termp *p, size_t sz)
536 {
537 
538 	if (0 == p->maxcols)
539 		p->maxcols = 1024;
540 	while (sz >= p->maxcols)
541 		p->maxcols <<= 2;
542 
543 	p->buf = mandoc_reallocarray(p->buf, p->maxcols, sizeof(int));
544 }
545 
546 static void
547 bufferc(struct termp *p, char c)
548 {
549 
550 	if (p->col + 1 >= p->maxcols)
551 		adjbuf(p, p->col + 1);
552 
553 	p->buf[p->col++] = c;
554 }
555 
556 /*
557  * See encode().
558  * Do this for a single (probably unicode) value.
559  * Does not check for non-decorated glyphs.
560  */
561 static void
562 encode1(struct termp *p, int c)
563 {
564 	enum termfont	  f;
565 
566 	if (p->col + 7 >= p->maxcols)
567 		adjbuf(p, p->col + 7);
568 
569 	f = (c == ASCII_HYPH || c > 127 || isgraph(c)) ?
570 	    p->fontq[p->fonti] : TERMFONT_NONE;
571 
572 	if (p->flags & TERMP_BACKBEFORE) {
573 		if (p->buf[p->col - 1] == ' ' || p->buf[p->col - 1] == '\t')
574 			p->col--;
575 		else
576 			p->buf[p->col++] = 8;
577 		p->flags &= ~TERMP_BACKBEFORE;
578 	}
579 	if (TERMFONT_UNDER == f || TERMFONT_BI == f) {
580 		p->buf[p->col++] = '_';
581 		p->buf[p->col++] = 8;
582 	}
583 	if (TERMFONT_BOLD == f || TERMFONT_BI == f) {
584 		if (ASCII_HYPH == c)
585 			p->buf[p->col++] = '-';
586 		else
587 			p->buf[p->col++] = c;
588 		p->buf[p->col++] = 8;
589 	}
590 	p->buf[p->col++] = c;
591 	if (p->flags & TERMP_BACKAFTER) {
592 		p->flags |= TERMP_BACKBEFORE;
593 		p->flags &= ~TERMP_BACKAFTER;
594 	}
595 }
596 
597 static void
598 encode(struct termp *p, const char *word, size_t sz)
599 {
600 	size_t		  i;
601 
602 	if (p->col + 2 + (sz * 5) >= p->maxcols)
603 		adjbuf(p, p->col + 2 + (sz * 5));
604 
605 	for (i = 0; i < sz; i++) {
606 		if (ASCII_HYPH == word[i] ||
607 		    isgraph((unsigned char)word[i]))
608 			encode1(p, word[i]);
609 		else {
610 			p->buf[p->col++] = word[i];
611 
612 			/*
613 			 * Postpone the effect of \z while handling
614 			 * an overstrike sequence from ascii_uc2str().
615 			 */
616 
617 			if (word[i] == '\b' &&
618 			    (p->flags & TERMP_BACKBEFORE)) {
619 				p->flags &= ~TERMP_BACKBEFORE;
620 				p->flags |= TERMP_BACKAFTER;
621 			}
622 		}
623 	}
624 }
625 
626 void
627 term_setwidth(struct termp *p, const char *wstr)
628 {
629 	struct roffsu	 su;
630 	int		 iop, width;
631 
632 	iop = 0;
633 	width = 0;
634 	if (NULL != wstr) {
635 		switch (*wstr) {
636 		case '+':
637 			iop = 1;
638 			wstr++;
639 			break;
640 		case '-':
641 			iop = -1;
642 			wstr++;
643 			break;
644 		default:
645 			break;
646 		}
647 		if (a2roffsu(wstr, &su, SCALE_MAX))
648 			width = term_hspan(p, &su);
649 		else
650 			iop = 0;
651 	}
652 	(*p->setwidth)(p, iop, width);
653 }
654 
655 size_t
656 term_len(const struct termp *p, size_t sz)
657 {
658 
659 	return (*p->width)(p, ' ') * sz;
660 }
661 
662 static size_t
663 cond_width(const struct termp *p, int c, int *skip)
664 {
665 
666 	if (*skip) {
667 		(*skip) = 0;
668 		return 0;
669 	} else
670 		return (*p->width)(p, c);
671 }
672 
673 size_t
674 term_strlen(const struct termp *p, const char *cp)
675 {
676 	size_t		 sz, rsz, i;
677 	int		 ssz, skip, uc;
678 	const char	*seq, *rhs;
679 	enum mandoc_esc	 esc;
680 	static const char rej[] = { '\\', ASCII_NBRSP, ASCII_HYPH,
681 			ASCII_BREAK, '\0' };
682 
683 	/*
684 	 * Account for escaped sequences within string length
685 	 * calculations.  This follows the logic in term_word() as we
686 	 * must calculate the width of produced strings.
687 	 */
688 
689 	sz = 0;
690 	skip = 0;
691 	while ('\0' != *cp) {
692 		rsz = strcspn(cp, rej);
693 		for (i = 0; i < rsz; i++)
694 			sz += cond_width(p, *cp++, &skip);
695 
696 		switch (*cp) {
697 		case '\\':
698 			cp++;
699 			esc = mandoc_escape(&cp, &seq, &ssz);
700 			if (ESCAPE_ERROR == esc)
701 				continue;
702 
703 			rhs = NULL;
704 
705 			switch (esc) {
706 			case ESCAPE_UNICODE:
707 				uc = mchars_num2uc(seq + 1, ssz - 1);
708 				break;
709 			case ESCAPE_NUMBERED:
710 				uc = mchars_num2char(seq, ssz);
711 				if (uc < 0)
712 					continue;
713 				break;
714 			case ESCAPE_SPECIAL:
715 				if (p->enc == TERMENC_ASCII) {
716 					rhs = mchars_spec2str(seq, ssz, &rsz);
717 					if (rhs != NULL)
718 						break;
719 				} else {
720 					uc = mchars_spec2cp(seq, ssz);
721 					if (uc > 0)
722 						sz += cond_width(p, uc, &skip);
723 				}
724 				continue;
725 			case ESCAPE_SKIPCHAR:
726 				skip = 1;
727 				continue;
728 			case ESCAPE_OVERSTRIKE:
729 				rsz = 0;
730 				rhs = seq + ssz;
731 				while (seq < rhs) {
732 					if (*seq == '\\') {
733 						mandoc_escape(&seq, NULL, NULL);
734 						continue;
735 					}
736 					i = (*p->width)(p, *seq++);
737 					if (rsz < i)
738 						rsz = i;
739 				}
740 				sz += rsz;
741 				continue;
742 			default:
743 				continue;
744 			}
745 
746 			/*
747 			 * Common handling for Unicode and numbered
748 			 * character escape sequences.
749 			 */
750 
751 			if (rhs == NULL) {
752 				if (p->enc == TERMENC_ASCII) {
753 					rhs = ascii_uc2str(uc);
754 					rsz = strlen(rhs);
755 				} else {
756 					if ((uc < 0x20 && uc != 0x09) ||
757 					    (uc > 0x7E && uc < 0xA0))
758 						uc = 0xFFFD;
759 					sz += cond_width(p, uc, &skip);
760 					continue;
761 				}
762 			}
763 
764 			if (skip) {
765 				skip = 0;
766 				break;
767 			}
768 
769 			/*
770 			 * Common handling for all escape sequences
771 			 * printing more than one character.
772 			 */
773 
774 			for (i = 0; i < rsz; i++)
775 				sz += (*p->width)(p, *rhs++);
776 			break;
777 		case ASCII_NBRSP:
778 			sz += cond_width(p, ' ', &skip);
779 			cp++;
780 			break;
781 		case ASCII_HYPH:
782 			sz += cond_width(p, '-', &skip);
783 			cp++;
784 			break;
785 		default:
786 			break;
787 		}
788 	}
789 
790 	return sz;
791 }
792 
793 int
794 term_vspan(const struct termp *p, const struct roffsu *su)
795 {
796 	double		 r;
797 	int		 ri;
798 
799 	switch (su->unit) {
800 	case SCALE_BU:
801 		r = su->scale / 40.0;
802 		break;
803 	case SCALE_CM:
804 		r = su->scale * 6.0 / 2.54;
805 		break;
806 	case SCALE_FS:
807 		r = su->scale * 65536.0 / 40.0;
808 		break;
809 	case SCALE_IN:
810 		r = su->scale * 6.0;
811 		break;
812 	case SCALE_MM:
813 		r = su->scale * 0.006;
814 		break;
815 	case SCALE_PC:
816 		r = su->scale;
817 		break;
818 	case SCALE_PT:
819 		r = su->scale / 12.0;
820 		break;
821 	case SCALE_EN:
822 	case SCALE_EM:
823 		r = su->scale * 0.6;
824 		break;
825 	case SCALE_VS:
826 		r = su->scale;
827 		break;
828 	default:
829 		abort();
830 	}
831 	ri = r > 0.0 ? r + 0.4995 : r - 0.4995;
832 	return ri < 66 ? ri : 1;
833 }
834 
835 /*
836  * Convert a scaling width to basic units, rounding down.
837  */
838 int
839 term_hspan(const struct termp *p, const struct roffsu *su)
840 {
841 
842 	return (*p->hspan)(p, su);
843 }
844