xref: /openbsd-src/usr.bin/mandoc/html.c (revision 91f110e064cd7c194e59e019b83bb7496c1c84d4) 
1 /*	$Id: html.c,v 1.34 2014/03/21 22:17:01 schwarze Exp $ */
2 /*
3  * Copyright (c) 2008, 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
4  * Copyright (c) 2011, 2012, 2013, 2014 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 #include <sys/types.h>
19 
20 #include <assert.h>
21 #include <ctype.h>
22 #include <stdarg.h>
23 #include <stdio.h>
24 #include <stdint.h>
25 #include <stdlib.h>
26 #include <string.h>
27 #include <unistd.h>
28 
29 #include "mandoc.h"
30 #include "mandoc_aux.h"
31 #include "libmandoc.h"
32 #include "out.h"
33 #include "html.h"
34 #include "main.h"
35 
36 struct	htmldata {
37 	const char	 *name;
38 	int		  flags;
39 #define	HTML_CLRLINE	 (1 << 0)
40 #define	HTML_NOSTACK	 (1 << 1)
41 #define	HTML_AUTOCLOSE	 (1 << 2) /* Tag has auto-closure. */
42 };
43 
44 static	const struct htmldata htmltags[TAG_MAX] = {
45 	{"html",	HTML_CLRLINE}, /* TAG_HTML */
46 	{"head",	HTML_CLRLINE}, /* TAG_HEAD */
47 	{"body",	HTML_CLRLINE}, /* TAG_BODY */
48 	{"meta",	HTML_CLRLINE | HTML_NOSTACK | HTML_AUTOCLOSE}, /* TAG_META */
49 	{"title",	HTML_CLRLINE}, /* TAG_TITLE */
50 	{"div",		HTML_CLRLINE}, /* TAG_DIV */
51 	{"h1",		0}, /* TAG_H1 */
52 	{"h2",		0}, /* TAG_H2 */
53 	{"span",	0}, /* TAG_SPAN */
54 	{"link",	HTML_CLRLINE | HTML_NOSTACK | HTML_AUTOCLOSE}, /* TAG_LINK */
55 	{"br",		HTML_CLRLINE | HTML_NOSTACK | HTML_AUTOCLOSE}, /* TAG_BR */
56 	{"a",		0}, /* TAG_A */
57 	{"table",	HTML_CLRLINE}, /* TAG_TABLE */
58 	{"tbody",	HTML_CLRLINE}, /* TAG_TBODY */
59 	{"col",		HTML_CLRLINE | HTML_NOSTACK | HTML_AUTOCLOSE}, /* TAG_COL */
60 	{"tr",		HTML_CLRLINE}, /* TAG_TR */
61 	{"td",		HTML_CLRLINE}, /* TAG_TD */
62 	{"li",		HTML_CLRLINE}, /* TAG_LI */
63 	{"ul",		HTML_CLRLINE}, /* TAG_UL */
64 	{"ol",		HTML_CLRLINE}, /* TAG_OL */
65 	{"dl",		HTML_CLRLINE}, /* TAG_DL */
66 	{"dt",		HTML_CLRLINE}, /* TAG_DT */
67 	{"dd",		HTML_CLRLINE}, /* TAG_DD */
68 	{"blockquote",	HTML_CLRLINE}, /* TAG_BLOCKQUOTE */
69 	{"p",		HTML_CLRLINE | HTML_NOSTACK | HTML_AUTOCLOSE}, /* TAG_P */
70 	{"pre",		HTML_CLRLINE }, /* TAG_PRE */
71 	{"b",		0 }, /* TAG_B */
72 	{"i",		0 }, /* TAG_I */
73 	{"code",	0 }, /* TAG_CODE */
74 	{"small",	0 }, /* TAG_SMALL */
75 };
76 
77 static	const char	*const htmlattrs[ATTR_MAX] = {
78 	"http-equiv", /* ATTR_HTTPEQUIV */
79 	"content", /* ATTR_CONTENT */
80 	"name", /* ATTR_NAME */
81 	"rel", /* ATTR_REL */
82 	"href", /* ATTR_HREF */
83 	"type", /* ATTR_TYPE */
84 	"media", /* ATTR_MEDIA */
85 	"class", /* ATTR_CLASS */
86 	"style", /* ATTR_STYLE */
87 	"width", /* ATTR_WIDTH */
88 	"id", /* ATTR_ID */
89 	"summary", /* ATTR_SUMMARY */
90 	"align", /* ATTR_ALIGN */
91 	"colspan", /* ATTR_COLSPAN */
92 };
93 
94 static	const char	*const roffscales[SCALE_MAX] = {
95 	"cm", /* SCALE_CM */
96 	"in", /* SCALE_IN */
97 	"pc", /* SCALE_PC */
98 	"pt", /* SCALE_PT */
99 	"em", /* SCALE_EM */
100 	"em", /* SCALE_MM */
101 	"ex", /* SCALE_EN */
102 	"ex", /* SCALE_BU */
103 	"em", /* SCALE_VS */
104 	"ex", /* SCALE_FS */
105 };
106 
107 static	void	 bufncat(struct html *, const char *, size_t);
108 static	void	 print_ctag(struct html *, enum htmltag);
109 static	int	 print_encode(struct html *, const char *, int);
110 static	void	 print_metaf(struct html *, enum mandoc_esc);
111 static	void	 print_attr(struct html *, const char *, const char *);
112 static	void	 *ml_alloc(char *, enum htmltype);
113 
114 static void *
115 ml_alloc(char *outopts, enum htmltype type)
116 {
117 	struct html	*h;
118 	const char	*toks[5];
119 	char		*v;
120 
121 	toks[0] = "style";
122 	toks[1] = "man";
123 	toks[2] = "includes";
124 	toks[3] = "fragment";
125 	toks[4] = NULL;
126 
127 	h = mandoc_calloc(1, sizeof(struct html));
128 
129 	h->type = type;
130 	h->tags.head = NULL;
131 	h->symtab = mchars_alloc();
132 
133 	while (outopts && *outopts)
134 		switch (getsubopt(&outopts, UNCONST(toks), &v)) {
135 		case (0):
136 			h->style = v;
137 			break;
138 		case (1):
139 			h->base_man = v;
140 			break;
141 		case (2):
142 			h->base_includes = v;
143 			break;
144 		case (3):
145 			h->oflags |= HTML_FRAGMENT;
146 			break;
147 		default:
148 			break;
149 		}
150 
151 	return(h);
152 }
153 
154 void *
155 html_alloc(char *outopts)
156 {
157 
158 	return(ml_alloc(outopts, HTML_HTML_4_01_STRICT));
159 }
160 
161 
162 void *
163 xhtml_alloc(char *outopts)
164 {
165 
166 	return(ml_alloc(outopts, HTML_XHTML_1_0_STRICT));
167 }
168 
169 
170 void
171 html_free(void *p)
172 {
173 	struct tag	*tag;
174 	struct html	*h;
175 
176 	h = (struct html *)p;
177 
178 	while ((tag = h->tags.head) != NULL) {
179 		h->tags.head = tag->next;
180 		free(tag);
181 	}
182 
183 	if (h->symtab)
184 		mchars_free(h->symtab);
185 
186 	free(h);
187 }
188 
189 
190 void
191 print_gen_head(struct html *h)
192 {
193 	struct htmlpair	 tag[4];
194 
195 	tag[0].key = ATTR_HTTPEQUIV;
196 	tag[0].val = "Content-Type";
197 	tag[1].key = ATTR_CONTENT;
198 	tag[1].val = "text/html; charset=utf-8";
199 	print_otag(h, TAG_META, 2, tag);
200 
201 	tag[0].key = ATTR_NAME;
202 	tag[0].val = "resource-type";
203 	tag[1].key = ATTR_CONTENT;
204 	tag[1].val = "document";
205 	print_otag(h, TAG_META, 2, tag);
206 
207 	if (h->style) {
208 		tag[0].key = ATTR_REL;
209 		tag[0].val = "stylesheet";
210 		tag[1].key = ATTR_HREF;
211 		tag[1].val = h->style;
212 		tag[2].key = ATTR_TYPE;
213 		tag[2].val = "text/css";
214 		tag[3].key = ATTR_MEDIA;
215 		tag[3].val = "all";
216 		print_otag(h, TAG_LINK, 4, tag);
217 	}
218 }
219 
220 static void
221 print_metaf(struct html *h, enum mandoc_esc deco)
222 {
223 	enum htmlfont	 font;
224 
225 	switch (deco) {
226 	case (ESCAPE_FONTPREV):
227 		font = h->metal;
228 		break;
229 	case (ESCAPE_FONTITALIC):
230 		font = HTMLFONT_ITALIC;
231 		break;
232 	case (ESCAPE_FONTBOLD):
233 		font = HTMLFONT_BOLD;
234 		break;
235 	case (ESCAPE_FONTBI):
236 		font = HTMLFONT_BI;
237 		break;
238 	case (ESCAPE_FONT):
239 		/* FALLTHROUGH */
240 	case (ESCAPE_FONTROMAN):
241 		font = HTMLFONT_NONE;
242 		break;
243 	default:
244 		abort();
245 		/* NOTREACHED */
246 	}
247 
248 	if (h->metaf) {
249 		print_tagq(h, h->metaf);
250 		h->metaf = NULL;
251 	}
252 
253 	h->metal = h->metac;
254 	h->metac = font;
255 
256 	switch (font) {
257 	case (HTMLFONT_ITALIC):
258 		h->metaf = print_otag(h, TAG_I, 0, NULL);
259 		break;
260 	case (HTMLFONT_BOLD):
261 		h->metaf = print_otag(h, TAG_B, 0, NULL);
262 		break;
263 	case (HTMLFONT_BI):
264 		h->metaf = print_otag(h, TAG_B, 0, NULL);
265 		print_otag(h, TAG_I, 0, NULL);
266 		break;
267 	default:
268 		break;
269 	}
270 }
271 
272 int
273 html_strlen(const char *cp)
274 {
275 	size_t		 rsz;
276 	int		 skip, sz;
277 
278 	/*
279 	 * Account for escaped sequences within string length
280 	 * calculations.  This follows the logic in term_strlen() as we
281 	 * must calculate the width of produced strings.
282 	 * Assume that characters are always width of "1".  This is
283 	 * hacky, but it gets the job done for approximation of widths.
284 	 */
285 
286 	sz = 0;
287 	skip = 0;
288 	while (1) {
289 		rsz = strcspn(cp, "\\");
290 		if (rsz) {
291 			cp += rsz;
292 			if (skip) {
293 				skip = 0;
294 				rsz--;
295 			}
296 			sz += rsz;
297 		}
298 		if ('\0' == *cp)
299 			break;
300 		cp++;
301 		switch (mandoc_escape(&cp, NULL, NULL)) {
302 		case (ESCAPE_ERROR):
303 			return(sz);
304 		case (ESCAPE_UNICODE):
305 			/* FALLTHROUGH */
306 		case (ESCAPE_NUMBERED):
307 			/* FALLTHROUGH */
308 		case (ESCAPE_SPECIAL):
309 			if (skip)
310 				skip = 0;
311 			else
312 				sz++;
313 			break;
314 		case (ESCAPE_SKIPCHAR):
315 			skip = 1;
316 			break;
317 		default:
318 			break;
319 		}
320 	}
321 	return(sz);
322 }
323 
324 static int
325 print_encode(struct html *h, const char *p, int norecurse)
326 {
327 	size_t		 sz;
328 	int		 c, len, nospace;
329 	const char	*seq;
330 	enum mandoc_esc	 esc;
331 	static const char rejs[8] = { '\\', '<', '>', '&',
332 		ASCII_NBRSP, ASCII_HYPH, ASCII_BREAK, '\0' };
333 
334 	nospace = 0;
335 
336 	while ('\0' != *p) {
337 		if (HTML_SKIPCHAR & h->flags && '\\' != *p) {
338 			h->flags &= ~HTML_SKIPCHAR;
339 			p++;
340 			continue;
341 		}
342 
343 		sz = strcspn(p, rejs);
344 
345 		fwrite(p, 1, sz, stdout);
346 		p += (int)sz;
347 
348 		if ('\0' == *p)
349 			break;
350 
351 		switch (*p++) {
352 		case ('<'):
353 			printf("&lt;");
354 			continue;
355 		case ('>'):
356 			printf("&gt;");
357 			continue;
358 		case ('&'):
359 			printf("&amp;");
360 			continue;
361 		case (ASCII_NBRSP):
362 			putchar('-');
363 			continue;
364 		case (ASCII_HYPH):
365 			putchar('-');
366 			/* FALLTHROUGH */
367 		case (ASCII_BREAK):
368 			continue;
369 		default:
370 			break;
371 		}
372 
373 		esc = mandoc_escape(&p, &seq, &len);
374 		if (ESCAPE_ERROR == esc)
375 			break;
376 
377 		switch (esc) {
378 		case (ESCAPE_FONT):
379 			/* FALLTHROUGH */
380 		case (ESCAPE_FONTPREV):
381 			/* FALLTHROUGH */
382 		case (ESCAPE_FONTBOLD):
383 			/* FALLTHROUGH */
384 		case (ESCAPE_FONTITALIC):
385 			/* FALLTHROUGH */
386 		case (ESCAPE_FONTBI):
387 			/* FALLTHROUGH */
388 		case (ESCAPE_FONTROMAN):
389 			if (0 == norecurse)
390 				print_metaf(h, esc);
391 			continue;
392 		case (ESCAPE_SKIPCHAR):
393 			h->flags |= HTML_SKIPCHAR;
394 			continue;
395 		default:
396 			break;
397 		}
398 
399 		if (h->flags & HTML_SKIPCHAR) {
400 			h->flags &= ~HTML_SKIPCHAR;
401 			continue;
402 		}
403 
404 		switch (esc) {
405 		case (ESCAPE_UNICODE):
406 			/* Skip passed "u" header. */
407 			c = mchars_num2uc(seq + 1, len - 1);
408 			if ('\0' != c)
409 				printf("&#x%x;", c);
410 			break;
411 		case (ESCAPE_NUMBERED):
412 			c = mchars_num2char(seq, len);
413 			if ('\0' != c)
414 				putchar(c);
415 			break;
416 		case (ESCAPE_SPECIAL):
417 			c = mchars_spec2cp(h->symtab, seq, len);
418 			if (c > 0)
419 				printf("&#%d;", c);
420 			else if (-1 == c && 1 == len)
421 				putchar((int)*seq);
422 			break;
423 		case (ESCAPE_NOSPACE):
424 			if ('\0' == *p)
425 				nospace = 1;
426 			break;
427 		default:
428 			break;
429 		}
430 	}
431 
432 	return(nospace);
433 }
434 
435 
436 static void
437 print_attr(struct html *h, const char *key, const char *val)
438 {
439 	printf(" %s=\"", key);
440 	(void)print_encode(h, val, 1);
441 	putchar('\"');
442 }
443 
444 
445 struct tag *
446 print_otag(struct html *h, enum htmltag tag,
447 		int sz, const struct htmlpair *p)
448 {
449 	int		 i;
450 	struct tag	*t;
451 
452 	/* Push this tags onto the stack of open scopes. */
453 
454 	if ( ! (HTML_NOSTACK & htmltags[tag].flags)) {
455 		t = mandoc_malloc(sizeof(struct tag));
456 		t->tag = tag;
457 		t->next = h->tags.head;
458 		h->tags.head = t;
459 	} else
460 		t = NULL;
461 
462 	if ( ! (HTML_NOSPACE & h->flags))
463 		if ( ! (HTML_CLRLINE & htmltags[tag].flags)) {
464 			/* Manage keeps! */
465 			if ( ! (HTML_KEEP & h->flags)) {
466 				if (HTML_PREKEEP & h->flags)
467 					h->flags |= HTML_KEEP;
468 				putchar(' ');
469 			} else
470 				printf("&#160;");
471 		}
472 
473 	if ( ! (h->flags & HTML_NONOSPACE))
474 		h->flags &= ~HTML_NOSPACE;
475 	else
476 		h->flags |= HTML_NOSPACE;
477 
478 	/* Print out the tag name and attributes. */
479 
480 	printf("<%s", htmltags[tag].name);
481 	for (i = 0; i < sz; i++)
482 		print_attr(h, htmlattrs[p[i].key], p[i].val);
483 
484 	/* Add non-overridable attributes. */
485 
486 	if (TAG_HTML == tag && HTML_XHTML_1_0_STRICT == h->type) {
487 		print_attr(h, "xmlns", "http://www.w3.org/1999/xhtml");
488 		print_attr(h, "xml:lang", "en");
489 		print_attr(h, "lang", "en");
490 	}
491 
492 	/* Accommodate for XML "well-formed" singleton escaping. */
493 
494 	if (HTML_AUTOCLOSE & htmltags[tag].flags)
495 		switch (h->type) {
496 		case (HTML_XHTML_1_0_STRICT):
497 			putchar('/');
498 			break;
499 		default:
500 			break;
501 		}
502 
503 	putchar('>');
504 
505 	h->flags |= HTML_NOSPACE;
506 
507 	if ((HTML_AUTOCLOSE | HTML_CLRLINE) & htmltags[tag].flags)
508 		putchar('\n');
509 
510 	return(t);
511 }
512 
513 
514 static void
515 print_ctag(struct html *h, enum htmltag tag)
516 {
517 
518 	printf("</%s>", htmltags[tag].name);
519 	if (HTML_CLRLINE & htmltags[tag].flags) {
520 		h->flags |= HTML_NOSPACE;
521 		putchar('\n');
522 	}
523 }
524 
525 void
526 print_gen_decls(struct html *h)
527 {
528 	const char	*doctype;
529 	const char	*dtd;
530 	const char	*name;
531 
532 	switch (h->type) {
533 	case (HTML_HTML_4_01_STRICT):
534 		name = "HTML";
535 		doctype = "-//W3C//DTD HTML 4.01//EN";
536 		dtd = "http://www.w3.org/TR/html4/strict.dtd";
537 		break;
538 	default:
539 		puts("<?xml version=\"1.0\" encoding=\"UTF-8\"?>");
540 		name = "html";
541 		doctype = "-//W3C//DTD XHTML 1.0 Strict//EN";
542 		dtd = "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd";
543 		break;
544 	}
545 
546 	printf("<!DOCTYPE %s PUBLIC \"%s\" \"%s\">\n",
547 			name, doctype, dtd);
548 }
549 
550 void
551 print_text(struct html *h, const char *word)
552 {
553 
554 	if ( ! (HTML_NOSPACE & h->flags)) {
555 		/* Manage keeps! */
556 		if ( ! (HTML_KEEP & h->flags)) {
557 			if (HTML_PREKEEP & h->flags)
558 				h->flags |= HTML_KEEP;
559 			putchar(' ');
560 		} else
561 			printf("&#160;");
562 	}
563 
564 	assert(NULL == h->metaf);
565 	switch (h->metac) {
566 	case (HTMLFONT_ITALIC):
567 		h->metaf = print_otag(h, TAG_I, 0, NULL);
568 		break;
569 	case (HTMLFONT_BOLD):
570 		h->metaf = print_otag(h, TAG_B, 0, NULL);
571 		break;
572 	case (HTMLFONT_BI):
573 		h->metaf = print_otag(h, TAG_B, 0, NULL);
574 		print_otag(h, TAG_I, 0, NULL);
575 		break;
576 	default:
577 		break;
578 	}
579 
580 	assert(word);
581 	if ( ! print_encode(h, word, 0)) {
582 		if ( ! (h->flags & HTML_NONOSPACE))
583 			h->flags &= ~HTML_NOSPACE;
584 	} else
585 		h->flags |= HTML_NOSPACE;
586 
587 	if (h->metaf) {
588 		print_tagq(h, h->metaf);
589 		h->metaf = NULL;
590 	}
591 
592 	h->flags &= ~HTML_IGNDELIM;
593 }
594 
595 
596 void
597 print_tagq(struct html *h, const struct tag *until)
598 {
599 	struct tag	*tag;
600 
601 	while ((tag = h->tags.head) != NULL) {
602 		/*
603 		 * Remember to close out and nullify the current
604 		 * meta-font and table, if applicable.
605 		 */
606 		if (tag == h->metaf)
607 			h->metaf = NULL;
608 		if (tag == h->tblt)
609 			h->tblt = NULL;
610 		print_ctag(h, tag->tag);
611 		h->tags.head = tag->next;
612 		free(tag);
613 		if (until && tag == until)
614 			return;
615 	}
616 }
617 
618 
619 void
620 print_stagq(struct html *h, const struct tag *suntil)
621 {
622 	struct tag	*tag;
623 
624 	while ((tag = h->tags.head) != NULL) {
625 		if (suntil && tag == suntil)
626 			return;
627 		/*
628 		 * Remember to close out and nullify the current
629 		 * meta-font and table, if applicable.
630 		 */
631 		if (tag == h->metaf)
632 			h->metaf = NULL;
633 		if (tag == h->tblt)
634 			h->tblt = NULL;
635 		print_ctag(h, tag->tag);
636 		h->tags.head = tag->next;
637 		free(tag);
638 	}
639 }
640 
641 void
642 bufinit(struct html *h)
643 {
644 
645 	h->buf[0] = '\0';
646 	h->buflen = 0;
647 }
648 
649 void
650 bufcat_style(struct html *h, const char *key, const char *val)
651 {
652 
653 	bufcat(h, key);
654 	bufcat(h, ":");
655 	bufcat(h, val);
656 	bufcat(h, ";");
657 }
658 
659 void
660 bufcat(struct html *h, const char *p)
661 {
662 
663 	h->buflen = strlcat(h->buf, p, BUFSIZ);
664 	assert(h->buflen < BUFSIZ);
665 }
666 
667 void
668 bufcat_fmt(struct html *h, const char *fmt, ...)
669 {
670 	va_list		 ap;
671 
672 	va_start(ap, fmt);
673 	(void)vsnprintf(h->buf + (int)h->buflen,
674 			BUFSIZ - h->buflen - 1, fmt, ap);
675 	va_end(ap);
676 	h->buflen = strlen(h->buf);
677 }
678 
679 static void
680 bufncat(struct html *h, const char *p, size_t sz)
681 {
682 
683 	assert(h->buflen + sz + 1 < BUFSIZ);
684 	strncat(h->buf, p, sz);
685 	h->buflen += sz;
686 }
687 
688 void
689 buffmt_includes(struct html *h, const char *name)
690 {
691 	const char	*p, *pp;
692 
693 	pp = h->base_includes;
694 
695 	bufinit(h);
696 	while (NULL != (p = strchr(pp, '%'))) {
697 		bufncat(h, pp, (size_t)(p - pp));
698 		switch (*(p + 1)) {
699 		case('I'):
700 			bufcat(h, name);
701 			break;
702 		default:
703 			bufncat(h, p, 2);
704 			break;
705 		}
706 		pp = p + 2;
707 	}
708 	if (pp)
709 		bufcat(h, pp);
710 }
711 
712 void
713 buffmt_man(struct html *h,
714 		const char *name, const char *sec)
715 {
716 	const char	*p, *pp;
717 
718 	pp = h->base_man;
719 
720 	bufinit(h);
721 	while (NULL != (p = strchr(pp, '%'))) {
722 		bufncat(h, pp, (size_t)(p - pp));
723 		switch (*(p + 1)) {
724 		case('S'):
725 			bufcat(h, sec ? sec : "1");
726 			break;
727 		case('N'):
728 			bufcat_fmt(h, "%s", name);
729 			break;
730 		default:
731 			bufncat(h, p, 2);
732 			break;
733 		}
734 		pp = p + 2;
735 	}
736 	if (pp)
737 		bufcat(h, pp);
738 }
739 
740 void
741 bufcat_su(struct html *h, const char *p, const struct roffsu *su)
742 {
743 	double		 v;
744 
745 	v = su->scale;
746 	if (SCALE_MM == su->unit && 0.0 == (v /= 100.0))
747 		v = 1.0;
748 
749 	bufcat_fmt(h, "%s: %.2f%s;", p, v, roffscales[su->unit]);
750 }
751 
752 void
753 bufcat_id(struct html *h, const char *src)
754 {
755 
756 	/* Cf. <http://www.w3.org/TR/html4/types.html#h-6.2>. */
757 
758 	while ('\0' != *src)
759 		bufcat_fmt(h, "%.2x", *src++);
760 }
761