xref: /titanic_50/usr/src/cmd/mandoc/html.c (revision 6aa4fc89ec1cf2cdf7d7c3b9ec059802ac9abe65) 
1 /*	$Id: html.c,v 1.152 2013/08/08 20:07:47 schwarze Exp $ */
2 /*
3  * Copyright (c) 2008, 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
4  * Copyright (c) 2011, 2012, 2013 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 AUTHOR DISCLAIMS ALL WARRANTIES
11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR 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 #ifdef HAVE_CONFIG_H
19 #include "config.h"
20 #endif
21 
22 #include <sys/types.h>
23 
24 #include <assert.h>
25 #include <ctype.h>
26 #include <stdarg.h>
27 #include <stdio.h>
28 #include <stdint.h>
29 #include <stdlib.h>
30 #include <string.h>
31 #include <unistd.h>
32 
33 #include "mandoc.h"
34 #include "libmandoc.h"
35 #include "out.h"
36 #include "html.h"
37 #include "main.h"
38 
39 struct	htmldata {
40 	const char	 *name;
41 	int		  flags;
42 #define	HTML_CLRLINE	 (1 << 0)
43 #define	HTML_NOSTACK	 (1 << 1)
44 #define	HTML_AUTOCLOSE	 (1 << 2) /* Tag has auto-closure. */
45 };
46 
47 static	const struct htmldata htmltags[TAG_MAX] = {
48 	{"html",	HTML_CLRLINE}, /* TAG_HTML */
49 	{"head",	HTML_CLRLINE}, /* TAG_HEAD */
50 	{"body",	HTML_CLRLINE}, /* TAG_BODY */
51 	{"meta",	HTML_CLRLINE | HTML_NOSTACK | HTML_AUTOCLOSE}, /* TAG_META */
52 	{"title",	HTML_CLRLINE}, /* TAG_TITLE */
53 	{"div",		HTML_CLRLINE}, /* TAG_DIV */
54 	{"h1",		0}, /* TAG_H1 */
55 	{"h2",		0}, /* TAG_H2 */
56 	{"span",	0}, /* TAG_SPAN */
57 	{"link",	HTML_CLRLINE | HTML_NOSTACK | HTML_AUTOCLOSE}, /* TAG_LINK */
58 	{"br",		HTML_CLRLINE | HTML_NOSTACK | HTML_AUTOCLOSE}, /* TAG_BR */
59 	{"a",		0}, /* TAG_A */
60 	{"table",	HTML_CLRLINE}, /* TAG_TABLE */
61 	{"tbody",	HTML_CLRLINE}, /* TAG_TBODY */
62 	{"col",		HTML_CLRLINE | HTML_NOSTACK | HTML_AUTOCLOSE}, /* TAG_COL */
63 	{"tr",		HTML_CLRLINE}, /* TAG_TR */
64 	{"td",		HTML_CLRLINE}, /* TAG_TD */
65 	{"li",		HTML_CLRLINE}, /* TAG_LI */
66 	{"ul",		HTML_CLRLINE}, /* TAG_UL */
67 	{"ol",		HTML_CLRLINE}, /* TAG_OL */
68 	{"dl",		HTML_CLRLINE}, /* TAG_DL */
69 	{"dt",		HTML_CLRLINE}, /* TAG_DT */
70 	{"dd",		HTML_CLRLINE}, /* TAG_DD */
71 	{"blockquote",	HTML_CLRLINE}, /* TAG_BLOCKQUOTE */
72 	{"p",		HTML_CLRLINE | HTML_NOSTACK | HTML_AUTOCLOSE}, /* TAG_P */
73 	{"pre",		HTML_CLRLINE }, /* TAG_PRE */
74 	{"b",		0 }, /* TAG_B */
75 	{"i",		0 }, /* TAG_I */
76 	{"code",	0 }, /* TAG_CODE */
77 	{"small",	0 }, /* TAG_SMALL */
78 };
79 
80 static	const char	*const htmlattrs[ATTR_MAX] = {
81 	"http-equiv", /* ATTR_HTTPEQUIV */
82 	"content", /* ATTR_CONTENT */
83 	"name", /* ATTR_NAME */
84 	"rel", /* ATTR_REL */
85 	"href", /* ATTR_HREF */
86 	"type", /* ATTR_TYPE */
87 	"media", /* ATTR_MEDIA */
88 	"class", /* ATTR_CLASS */
89 	"style", /* ATTR_STYLE */
90 	"width", /* ATTR_WIDTH */
91 	"id", /* ATTR_ID */
92 	"summary", /* ATTR_SUMMARY */
93 	"align", /* ATTR_ALIGN */
94 	"colspan", /* ATTR_COLSPAN */
95 };
96 
97 static	const char	*const roffscales[SCALE_MAX] = {
98 	"cm", /* SCALE_CM */
99 	"in", /* SCALE_IN */
100 	"pc", /* SCALE_PC */
101 	"pt", /* SCALE_PT */
102 	"em", /* SCALE_EM */
103 	"em", /* SCALE_MM */
104 	"ex", /* SCALE_EN */
105 	"ex", /* SCALE_BU */
106 	"em", /* SCALE_VS */
107 	"ex", /* SCALE_FS */
108 };
109 
110 static	void	 bufncat(struct html *, const char *, size_t);
111 static	void	 print_ctag(struct html *, enum htmltag);
112 static	int	 print_encode(struct html *, const char *, int);
113 static	void	 print_metaf(struct html *, enum mandoc_esc);
114 static	void	 print_attr(struct html *, const char *, const char *);
115 static	void	 *ml_alloc(char *, enum htmltype);
116 
117 static void *
118 ml_alloc(char *outopts, enum htmltype type)
119 {
120 	struct html	*h;
121 	const char	*toks[5];
122 	char		*v;
123 
124 	toks[0] = "style";
125 	toks[1] = "man";
126 	toks[2] = "includes";
127 	toks[3] = "fragment";
128 	toks[4] = NULL;
129 
130 	h = mandoc_calloc(1, sizeof(struct html));
131 
132 	h->type = type;
133 	h->tags.head = NULL;
134 	h->symtab = mchars_alloc();
135 
136 	while (outopts && *outopts)
137 		switch (getsubopt(&outopts, UNCONST(toks), &v)) {
138 		case (0):
139 			h->style = v;
140 			break;
141 		case (1):
142 			h->base_man = v;
143 			break;
144 		case (2):
145 			h->base_includes = v;
146 			break;
147 		case (3):
148 			h->oflags |= HTML_FRAGMENT;
149 			break;
150 		default:
151 			break;
152 		}
153 
154 	return(h);
155 }
156 
157 void *
158 html_alloc(char *outopts)
159 {
160 
161 	return(ml_alloc(outopts, HTML_HTML_4_01_STRICT));
162 }
163 
164 
165 void *
166 xhtml_alloc(char *outopts)
167 {
168 
169 	return(ml_alloc(outopts, HTML_XHTML_1_0_STRICT));
170 }
171 
172 
173 void
174 html_free(void *p)
175 {
176 	struct tag	*tag;
177 	struct html	*h;
178 
179 	h = (struct html *)p;
180 
181 	while ((tag = h->tags.head) != NULL) {
182 		h->tags.head = tag->next;
183 		free(tag);
184 	}
185 
186 	if (h->symtab)
187 		mchars_free(h->symtab);
188 
189 	free(h);
190 }
191 
192 
193 void
194 print_gen_head(struct html *h)
195 {
196 	struct htmlpair	 tag[4];
197 
198 	tag[0].key = ATTR_HTTPEQUIV;
199 	tag[0].val = "Content-Type";
200 	tag[1].key = ATTR_CONTENT;
201 	tag[1].val = "text/html; charset=utf-8";
202 	print_otag(h, TAG_META, 2, tag);
203 
204 	tag[0].key = ATTR_NAME;
205 	tag[0].val = "resource-type";
206 	tag[1].key = ATTR_CONTENT;
207 	tag[1].val = "document";
208 	print_otag(h, TAG_META, 2, tag);
209 
210 	if (h->style) {
211 		tag[0].key = ATTR_REL;
212 		tag[0].val = "stylesheet";
213 		tag[1].key = ATTR_HREF;
214 		tag[1].val = h->style;
215 		tag[2].key = ATTR_TYPE;
216 		tag[2].val = "text/css";
217 		tag[3].key = ATTR_MEDIA;
218 		tag[3].val = "all";
219 		print_otag(h, TAG_LINK, 4, tag);
220 	}
221 }
222 
223 static void
224 print_metaf(struct html *h, enum mandoc_esc deco)
225 {
226 	enum htmlfont	 font;
227 
228 	switch (deco) {
229 	case (ESCAPE_FONTPREV):
230 		font = h->metal;
231 		break;
232 	case (ESCAPE_FONTITALIC):
233 		font = HTMLFONT_ITALIC;
234 		break;
235 	case (ESCAPE_FONTBOLD):
236 		font = HTMLFONT_BOLD;
237 		break;
238 	case (ESCAPE_FONTBI):
239 		font = HTMLFONT_BI;
240 		break;
241 	case (ESCAPE_FONT):
242 		/* FALLTHROUGH */
243 	case (ESCAPE_FONTROMAN):
244 		font = HTMLFONT_NONE;
245 		break;
246 	default:
247 		abort();
248 		/* NOTREACHED */
249 	}
250 
251 	if (h->metaf) {
252 		print_tagq(h, h->metaf);
253 		h->metaf = NULL;
254 	}
255 
256 	h->metal = h->metac;
257 	h->metac = font;
258 
259 	switch (font) {
260 	case (HTMLFONT_ITALIC):
261 		h->metaf = print_otag(h, TAG_I, 0, NULL);
262 		break;
263 	case (HTMLFONT_BOLD):
264 		h->metaf = print_otag(h, TAG_B, 0, NULL);
265 		break;
266 	case (HTMLFONT_BI):
267 		h->metaf = print_otag(h, TAG_B, 0, NULL);
268 		print_otag(h, TAG_I, 0, NULL);
269 		break;
270 	default:
271 		break;
272 	}
273 }
274 
275 int
276 html_strlen(const char *cp)
277 {
278 	size_t		 rsz;
279 	int		 skip, sz;
280 
281 	/*
282 	 * Account for escaped sequences within string length
283 	 * calculations.  This follows the logic in term_strlen() as we
284 	 * must calculate the width of produced strings.
285 	 * Assume that characters are always width of "1".  This is
286 	 * hacky, but it gets the job done for approximation of widths.
287 	 */
288 
289 	sz = 0;
290 	skip = 0;
291 	while (1) {
292 		rsz = strcspn(cp, "\\");
293 		if (rsz) {
294 			cp += rsz;
295 			if (skip) {
296 				skip = 0;
297 				rsz--;
298 			}
299 			sz += rsz;
300 		}
301 		if ('\0' == *cp)
302 			break;
303 		cp++;
304 		switch (mandoc_escape(&cp, NULL, NULL)) {
305 		case (ESCAPE_ERROR):
306 			return(sz);
307 		case (ESCAPE_UNICODE):
308 			/* FALLTHROUGH */
309 		case (ESCAPE_NUMBERED):
310 			/* FALLTHROUGH */
311 		case (ESCAPE_SPECIAL):
312 			if (skip)
313 				skip = 0;
314 			else
315 				sz++;
316 			break;
317 		case (ESCAPE_SKIPCHAR):
318 			skip = 1;
319 			break;
320 		default:
321 			break;
322 		}
323 	}
324 	return(sz);
325 }
326 
327 static int
328 print_encode(struct html *h, const char *p, int norecurse)
329 {
330 	size_t		 sz;
331 	int		 c, len, nospace;
332 	const char	*seq;
333 	enum mandoc_esc	 esc;
334 	static const char rejs[6] = { '\\', '<', '>', '&', ASCII_HYPH, '\0' };
335 
336 	nospace = 0;
337 
338 	while ('\0' != *p) {
339 		if (HTML_SKIPCHAR & h->flags && '\\' != *p) {
340 			h->flags &= ~HTML_SKIPCHAR;
341 			p++;
342 			continue;
343 		}
344 
345 		sz = strcspn(p, rejs);
346 
347 		fwrite(p, 1, sz, stdout);
348 		p += (int)sz;
349 
350 		if ('\0' == *p)
351 			break;
352 
353 		switch (*p++) {
354 		case ('<'):
355 			printf("&lt;");
356 			continue;
357 		case ('>'):
358 			printf("&gt;");
359 			continue;
360 		case ('&'):
361 			printf("&amp;");
362 			continue;
363 		case (ASCII_HYPH):
364 			putchar('-');
365 			continue;
366 		default:
367 			break;
368 		}
369 
370 		esc = mandoc_escape(&p, &seq, &len);
371 		if (ESCAPE_ERROR == esc)
372 			break;
373 
374 		switch (esc) {
375 		case (ESCAPE_FONT):
376 			/* FALLTHROUGH */
377 		case (ESCAPE_FONTPREV):
378 			/* FALLTHROUGH */
379 		case (ESCAPE_FONTBOLD):
380 			/* FALLTHROUGH */
381 		case (ESCAPE_FONTITALIC):
382 			/* FALLTHROUGH */
383 		case (ESCAPE_FONTBI):
384 			/* FALLTHROUGH */
385 		case (ESCAPE_FONTROMAN):
386 			if (0 == norecurse)
387 				print_metaf(h, esc);
388 			continue;
389 		case (ESCAPE_SKIPCHAR):
390 			h->flags |= HTML_SKIPCHAR;
391 			continue;
392 		default:
393 			break;
394 		}
395 
396 		if (h->flags & HTML_SKIPCHAR) {
397 			h->flags &= ~HTML_SKIPCHAR;
398 			continue;
399 		}
400 
401 		switch (esc) {
402 		case (ESCAPE_UNICODE):
403 			/* Skip passed "u" header. */
404 			c = mchars_num2uc(seq + 1, len - 1);
405 			if ('\0' != c)
406 				printf("&#x%x;", c);
407 			break;
408 		case (ESCAPE_NUMBERED):
409 			c = mchars_num2char(seq, len);
410 			if ('\0' != c)
411 				putchar(c);
412 			break;
413 		case (ESCAPE_SPECIAL):
414 			c = mchars_spec2cp(h->symtab, seq, len);
415 			if (c > 0)
416 				printf("&#%d;", c);
417 			else if (-1 == c && 1 == len)
418 				putchar((int)*seq);
419 			break;
420 		case (ESCAPE_NOSPACE):
421 			if ('\0' == *p)
422 				nospace = 1;
423 			break;
424 		default:
425 			break;
426 		}
427 	}
428 
429 	return(nospace);
430 }
431 
432 
433 static void
434 print_attr(struct html *h, const char *key, const char *val)
435 {
436 	printf(" %s=\"", key);
437 	(void)print_encode(h, val, 1);
438 	putchar('\"');
439 }
440 
441 
442 struct tag *
443 print_otag(struct html *h, enum htmltag tag,
444 		int sz, const struct htmlpair *p)
445 {
446 	int		 i;
447 	struct tag	*t;
448 
449 	/* Push this tags onto the stack of open scopes. */
450 
451 	if ( ! (HTML_NOSTACK & htmltags[tag].flags)) {
452 		t = mandoc_malloc(sizeof(struct tag));
453 		t->tag = tag;
454 		t->next = h->tags.head;
455 		h->tags.head = t;
456 	} else
457 		t = NULL;
458 
459 	if ( ! (HTML_NOSPACE & h->flags))
460 		if ( ! (HTML_CLRLINE & htmltags[tag].flags)) {
461 			/* Manage keeps! */
462 			if ( ! (HTML_KEEP & h->flags)) {
463 				if (HTML_PREKEEP & h->flags)
464 					h->flags |= HTML_KEEP;
465 				putchar(' ');
466 			} else
467 				printf("&#160;");
468 		}
469 
470 	if ( ! (h->flags & HTML_NONOSPACE))
471 		h->flags &= ~HTML_NOSPACE;
472 	else
473 		h->flags |= HTML_NOSPACE;
474 
475 	/* Print out the tag name and attributes. */
476 
477 	printf("<%s", htmltags[tag].name);
478 	for (i = 0; i < sz; i++)
479 		print_attr(h, htmlattrs[p[i].key], p[i].val);
480 
481 	/* Add non-overridable attributes. */
482 
483 	if (TAG_HTML == tag && HTML_XHTML_1_0_STRICT == h->type) {
484 		print_attr(h, "xmlns", "http://www.w3.org/1999/xhtml");
485 		print_attr(h, "xml:lang", "en");
486 		print_attr(h, "lang", "en");
487 	}
488 
489 	/* Accommodate for XML "well-formed" singleton escaping. */
490 
491 	if (HTML_AUTOCLOSE & htmltags[tag].flags)
492 		switch (h->type) {
493 		case (HTML_XHTML_1_0_STRICT):
494 			putchar('/');
495 			break;
496 		default:
497 			break;
498 		}
499 
500 	putchar('>');
501 
502 	h->flags |= HTML_NOSPACE;
503 
504 	if ((HTML_AUTOCLOSE | HTML_CLRLINE) & htmltags[tag].flags)
505 		putchar('\n');
506 
507 	return(t);
508 }
509 
510 
511 static void
512 print_ctag(struct html *h, enum htmltag tag)
513 {
514 
515 	printf("</%s>", htmltags[tag].name);
516 	if (HTML_CLRLINE & htmltags[tag].flags) {
517 		h->flags |= HTML_NOSPACE;
518 		putchar('\n');
519 	}
520 }
521 
522 void
523 print_gen_decls(struct html *h)
524 {
525 	const char	*doctype;
526 	const char	*dtd;
527 	const char	*name;
528 
529 	switch (h->type) {
530 	case (HTML_HTML_4_01_STRICT):
531 		name = "HTML";
532 		doctype = "-//W3C//DTD HTML 4.01//EN";
533 		dtd = "http://www.w3.org/TR/html4/strict.dtd";
534 		break;
535 	default:
536 		puts("<?xml version=\"1.0\" encoding=\"UTF-8\"?>");
537 		name = "html";
538 		doctype = "-//W3C//DTD XHTML 1.0 Strict//EN";
539 		dtd = "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd";
540 		break;
541 	}
542 
543 	printf("<!DOCTYPE %s PUBLIC \"%s\" \"%s\">\n",
544 			name, doctype, dtd);
545 }
546 
547 void
548 print_text(struct html *h, const char *word)
549 {
550 
551 	if ( ! (HTML_NOSPACE & h->flags)) {
552 		/* Manage keeps! */
553 		if ( ! (HTML_KEEP & h->flags)) {
554 			if (HTML_PREKEEP & h->flags)
555 				h->flags |= HTML_KEEP;
556 			putchar(' ');
557 		} else
558 			printf("&#160;");
559 	}
560 
561 	assert(NULL == h->metaf);
562 	switch (h->metac) {
563 	case (HTMLFONT_ITALIC):
564 		h->metaf = print_otag(h, TAG_I, 0, NULL);
565 		break;
566 	case (HTMLFONT_BOLD):
567 		h->metaf = print_otag(h, TAG_B, 0, NULL);
568 		break;
569 	case (HTMLFONT_BI):
570 		h->metaf = print_otag(h, TAG_B, 0, NULL);
571 		print_otag(h, TAG_I, 0, NULL);
572 		break;
573 	default:
574 		break;
575 	}
576 
577 	assert(word);
578 	if ( ! print_encode(h, word, 0)) {
579 		if ( ! (h->flags & HTML_NONOSPACE))
580 			h->flags &= ~HTML_NOSPACE;
581 	} else
582 		h->flags |= HTML_NOSPACE;
583 
584 	if (h->metaf) {
585 		print_tagq(h, h->metaf);
586 		h->metaf = NULL;
587 	}
588 
589 	h->flags &= ~HTML_IGNDELIM;
590 }
591 
592 
593 void
594 print_tagq(struct html *h, const struct tag *until)
595 {
596 	struct tag	*tag;
597 
598 	while ((tag = h->tags.head) != NULL) {
599 		/*
600 		 * Remember to close out and nullify the current
601 		 * meta-font and table, if applicable.
602 		 */
603 		if (tag == h->metaf)
604 			h->metaf = NULL;
605 		if (tag == h->tblt)
606 			h->tblt = NULL;
607 		print_ctag(h, tag->tag);
608 		h->tags.head = tag->next;
609 		free(tag);
610 		if (until && tag == until)
611 			return;
612 	}
613 }
614 
615 
616 void
617 print_stagq(struct html *h, const struct tag *suntil)
618 {
619 	struct tag	*tag;
620 
621 	while ((tag = h->tags.head) != NULL) {
622 		if (suntil && tag == suntil)
623 			return;
624 		/*
625 		 * Remember to close out and nullify the current
626 		 * meta-font and table, if applicable.
627 		 */
628 		if (tag == h->metaf)
629 			h->metaf = NULL;
630 		if (tag == h->tblt)
631 			h->tblt = NULL;
632 		print_ctag(h, tag->tag);
633 		h->tags.head = tag->next;
634 		free(tag);
635 	}
636 }
637 
638 void
639 bufinit(struct html *h)
640 {
641 
642 	h->buf[0] = '\0';
643 	h->buflen = 0;
644 }
645 
646 void
647 bufcat_style(struct html *h, const char *key, const char *val)
648 {
649 
650 	bufcat(h, key);
651 	bufcat(h, ":");
652 	bufcat(h, val);
653 	bufcat(h, ";");
654 }
655 
656 void
657 bufcat(struct html *h, const char *p)
658 {
659 
660 	h->buflen = strlcat(h->buf, p, BUFSIZ);
661 	assert(h->buflen < BUFSIZ);
662 }
663 
664 void
665 bufcat_fmt(struct html *h, const char *fmt, ...)
666 {
667 	va_list		 ap;
668 
669 	va_start(ap, fmt);
670 	(void)vsnprintf(h->buf + (int)h->buflen,
671 			BUFSIZ - h->buflen - 1, fmt, ap);
672 	va_end(ap);
673 	h->buflen = strlen(h->buf);
674 }
675 
676 static void
677 bufncat(struct html *h, const char *p, size_t sz)
678 {
679 
680 	assert(h->buflen + sz + 1 < BUFSIZ);
681 	strncat(h->buf, p, sz);
682 	h->buflen += sz;
683 }
684 
685 void
686 buffmt_includes(struct html *h, const char *name)
687 {
688 	const char	*p, *pp;
689 
690 	pp = h->base_includes;
691 
692 	bufinit(h);
693 	while (NULL != (p = strchr(pp, '%'))) {
694 		bufncat(h, pp, (size_t)(p - pp));
695 		switch (*(p + 1)) {
696 		case('I'):
697 			bufcat(h, name);
698 			break;
699 		default:
700 			bufncat(h, p, 2);
701 			break;
702 		}
703 		pp = p + 2;
704 	}
705 	if (pp)
706 		bufcat(h, pp);
707 }
708 
709 void
710 buffmt_man(struct html *h,
711 		const char *name, const char *sec)
712 {
713 	const char	*p, *pp;
714 
715 	pp = h->base_man;
716 
717 	bufinit(h);
718 	while (NULL != (p = strchr(pp, '%'))) {
719 		bufncat(h, pp, (size_t)(p - pp));
720 		switch (*(p + 1)) {
721 		case('S'):
722 			bufcat(h, sec ? sec : "1");
723 			break;
724 		case('N'):
725 			bufcat_fmt(h, name);
726 			break;
727 		default:
728 			bufncat(h, p, 2);
729 			break;
730 		}
731 		pp = p + 2;
732 	}
733 	if (pp)
734 		bufcat(h, pp);
735 }
736 
737 void
738 bufcat_su(struct html *h, const char *p, const struct roffsu *su)
739 {
740 	double		 v;
741 
742 	v = su->scale;
743 	if (SCALE_MM == su->unit && 0.0 == (v /= 100.0))
744 		v = 1.0;
745 
746 	bufcat_fmt(h, "%s: %.2f%s;", p, v, roffscales[su->unit]);
747 }
748 
749 void
750 bufcat_id(struct html *h, const char *src)
751 {
752 
753 	/* Cf. <http://www.w3.org/TR/html4/types.html#h-6.2>. */
754 
755 	while ('\0' != *src)
756 		bufcat_fmt(h, "%.2x", *src++);
757 }
758