xref: /dragonfly/contrib/mdocml/html.c (revision b29f78b5) 
1 /*	$Id: html.c,v 1.159 2014/07/23 15:00:08 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 #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 "mandoc_aux.h"
35 #include "libmandoc.h"
36 #include "out.h"
37 #include "html.h"
38 #include "main.h"
39 
40 struct	htmldata {
41 	const char	 *name;
42 	int		  flags;
43 #define	HTML_CLRLINE	 (1 << 0)
44 #define	HTML_NOSTACK	 (1 << 1)
45 #define	HTML_AUTOCLOSE	 (1 << 2) /* Tag has auto-closure. */
46 };
47 
48 static	const struct htmldata htmltags[TAG_MAX] = {
49 	{"html",	HTML_CLRLINE}, /* TAG_HTML */
50 	{"head",	HTML_CLRLINE}, /* TAG_HEAD */
51 	{"body",	HTML_CLRLINE}, /* TAG_BODY */
52 	{"meta",	HTML_CLRLINE | HTML_NOSTACK | HTML_AUTOCLOSE}, /* TAG_META */
53 	{"title",	HTML_CLRLINE}, /* TAG_TITLE */
54 	{"div",		HTML_CLRLINE}, /* TAG_DIV */
55 	{"h1",		0}, /* TAG_H1 */
56 	{"h2",		0}, /* TAG_H2 */
57 	{"span",	0}, /* TAG_SPAN */
58 	{"link",	HTML_CLRLINE | HTML_NOSTACK | HTML_AUTOCLOSE}, /* TAG_LINK */
59 	{"br",		HTML_CLRLINE | HTML_NOSTACK | HTML_AUTOCLOSE}, /* TAG_BR */
60 	{"a",		0}, /* TAG_A */
61 	{"table",	HTML_CLRLINE}, /* TAG_TABLE */
62 	{"tbody",	HTML_CLRLINE}, /* TAG_TBODY */
63 	{"col",		HTML_CLRLINE | HTML_NOSTACK | HTML_AUTOCLOSE}, /* TAG_COL */
64 	{"tr",		HTML_CLRLINE}, /* TAG_TR */
65 	{"td",		HTML_CLRLINE}, /* TAG_TD */
66 	{"li",		HTML_CLRLINE}, /* TAG_LI */
67 	{"ul",		HTML_CLRLINE}, /* TAG_UL */
68 	{"ol",		HTML_CLRLINE}, /* TAG_OL */
69 	{"dl",		HTML_CLRLINE}, /* TAG_DL */
70 	{"dt",		HTML_CLRLINE}, /* TAG_DT */
71 	{"dd",		HTML_CLRLINE}, /* TAG_DD */
72 	{"blockquote",	HTML_CLRLINE}, /* TAG_BLOCKQUOTE */
73 	{"p",		HTML_CLRLINE | HTML_NOSTACK | HTML_AUTOCLOSE}, /* TAG_P */
74 	{"pre",		HTML_CLRLINE }, /* TAG_PRE */
75 	{"b",		0 }, /* TAG_B */
76 	{"i",		0 }, /* TAG_I */
77 	{"code",	0 }, /* TAG_CODE */
78 	{"small",	0 }, /* TAG_SMALL */
79 };
80 
81 static	const char	*const htmlattrs[ATTR_MAX] = {
82 	"http-equiv", /* ATTR_HTTPEQUIV */
83 	"content", /* ATTR_CONTENT */
84 	"name", /* ATTR_NAME */
85 	"rel", /* ATTR_REL */
86 	"href", /* ATTR_HREF */
87 	"type", /* ATTR_TYPE */
88 	"media", /* ATTR_MEDIA */
89 	"class", /* ATTR_CLASS */
90 	"style", /* ATTR_STYLE */
91 	"width", /* ATTR_WIDTH */
92 	"id", /* ATTR_ID */
93 	"summary", /* ATTR_SUMMARY */
94 	"align", /* ATTR_ALIGN */
95 	"colspan", /* ATTR_COLSPAN */
96 };
97 
98 static	const char	*const roffscales[SCALE_MAX] = {
99 	"cm", /* SCALE_CM */
100 	"in", /* SCALE_IN */
101 	"pc", /* SCALE_PC */
102 	"pt", /* SCALE_PT */
103 	"em", /* SCALE_EM */
104 	"em", /* SCALE_MM */
105 	"ex", /* SCALE_EN */
106 	"ex", /* SCALE_BU */
107 	"em", /* SCALE_VS */
108 	"ex", /* SCALE_FS */
109 };
110 
111 static	void	 bufncat(struct html *, const char *, size_t);
112 static	void	 print_ctag(struct html *, enum htmltag);
113 static	int	 print_escape(char);
114 static	int	 print_encode(struct html *, const char *, int);
115 static	void	 print_metaf(struct html *, enum mandoc_esc);
116 static	void	 print_attr(struct html *, const char *, const char *);
117 static	void	 *ml_alloc(char *, enum htmltype);
118 
119 
120 static void *
121 ml_alloc(char *outopts, enum htmltype type)
122 {
123 	struct html	*h;
124 	const char	*toks[5];
125 	char		*v;
126 
127 	toks[0] = "style";
128 	toks[1] = "man";
129 	toks[2] = "includes";
130 	toks[3] = "fragment";
131 	toks[4] = NULL;
132 
133 	h = mandoc_calloc(1, sizeof(struct html));
134 
135 	h->type = type;
136 	h->tags.head = NULL;
137 	h->symtab = mchars_alloc();
138 
139 	while (outopts && *outopts)
140 		switch (getsubopt(&outopts, UNCONST(toks), &v)) {
141 		case 0:
142 			h->style = v;
143 			break;
144 		case 1:
145 			h->base_man = v;
146 			break;
147 		case 2:
148 			h->base_includes = v;
149 			break;
150 		case 3:
151 			h->oflags |= HTML_FRAGMENT;
152 			break;
153 		default:
154 			break;
155 		}
156 
157 	return(h);
158 }
159 
160 void *
161 html_alloc(char *outopts)
162 {
163 
164 	return(ml_alloc(outopts, HTML_HTML_4_01_STRICT));
165 }
166 
167 void *
168 xhtml_alloc(char *outopts)
169 {
170 
171 	return(ml_alloc(outopts, HTML_XHTML_1_0_STRICT));
172 }
173 
174 void
175 html_free(void *p)
176 {
177 	struct tag	*tag;
178 	struct html	*h;
179 
180 	h = (struct html *)p;
181 
182 	while ((tag = h->tags.head) != NULL) {
183 		h->tags.head = tag->next;
184 		free(tag);
185 	}
186 
187 	if (h->symtab)
188 		mchars_free(h->symtab);
189 
190 	free(h);
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_escape(char c)
329 {
330 
331 	switch (c) {
332 	case '<':
333 		printf("&lt;");
334 		break;
335 	case '>':
336 		printf("&gt;");
337 		break;
338 	case '&':
339 		printf("&amp;");
340 		break;
341 	case '"':
342 		printf("&quot;");
343 		break;
344 	case ASCII_NBRSP:
345 		putchar('-');
346 		break;
347 	case ASCII_HYPH:
348 		putchar('-');
349 		/* FALLTHROUGH */
350 	case ASCII_BREAK:
351 		break;
352 	default:
353 		return(0);
354 	}
355 	return(1);
356 }
357 
358 static int
359 print_encode(struct html *h, const char *p, int norecurse)
360 {
361 	size_t		 sz;
362 	int		 c, len, nospace;
363 	const char	*seq;
364 	enum mandoc_esc	 esc;
365 	static const char rejs[9] = { '\\', '<', '>', '&', '"',
366 		ASCII_NBRSP, ASCII_HYPH, ASCII_BREAK, '\0' };
367 
368 	nospace = 0;
369 
370 	while ('\0' != *p) {
371 		if (HTML_SKIPCHAR & h->flags && '\\' != *p) {
372 			h->flags &= ~HTML_SKIPCHAR;
373 			p++;
374 			continue;
375 		}
376 
377 		sz = strcspn(p, rejs);
378 
379 		fwrite(p, 1, sz, stdout);
380 		p += (int)sz;
381 
382 		if ('\0' == *p)
383 			break;
384 
385 		if (print_escape(*p++))
386 			continue;
387 
388 		esc = mandoc_escape(&p, &seq, &len);
389 		if (ESCAPE_ERROR == esc)
390 			break;
391 
392 		switch (esc) {
393 		case ESCAPE_FONT:
394 			/* FALLTHROUGH */
395 		case ESCAPE_FONTPREV:
396 			/* FALLTHROUGH */
397 		case ESCAPE_FONTBOLD:
398 			/* FALLTHROUGH */
399 		case ESCAPE_FONTITALIC:
400 			/* FALLTHROUGH */
401 		case ESCAPE_FONTBI:
402 			/* FALLTHROUGH */
403 		case ESCAPE_FONTROMAN:
404 			if (0 == norecurse)
405 				print_metaf(h, esc);
406 			continue;
407 		case ESCAPE_SKIPCHAR:
408 			h->flags |= HTML_SKIPCHAR;
409 			continue;
410 		default:
411 			break;
412 		}
413 
414 		if (h->flags & HTML_SKIPCHAR) {
415 			h->flags &= ~HTML_SKIPCHAR;
416 			continue;
417 		}
418 
419 		switch (esc) {
420 		case ESCAPE_UNICODE:
421 			/* Skip past "u" header. */
422 			c = mchars_num2uc(seq + 1, len - 1);
423 			if ('\0' != c)
424 				printf("&#x%x;", c);
425 			break;
426 		case ESCAPE_NUMBERED:
427 			c = mchars_num2char(seq, len);
428 			if ( ! ('\0' == c || print_escape(c)))
429 				putchar(c);
430 			break;
431 		case ESCAPE_SPECIAL:
432 			c = mchars_spec2cp(h->symtab, seq, len);
433 			if (c > 0)
434 				printf("&#%d;", c);
435 			else if (-1 == c && 1 == len &&
436 			    !print_escape(*seq))
437 				putchar((int)*seq);
438 			break;
439 		case ESCAPE_NOSPACE:
440 			if ('\0' == *p)
441 				nospace = 1;
442 			break;
443 		default:
444 			break;
445 		}
446 	}
447 
448 	return(nospace);
449 }
450 
451 static void
452 print_attr(struct html *h, const char *key, const char *val)
453 {
454 	printf(" %s=\"", key);
455 	(void)print_encode(h, val, 1);
456 	putchar('\"');
457 }
458 
459 struct tag *
460 print_otag(struct html *h, enum htmltag tag,
461 		int sz, const struct htmlpair *p)
462 {
463 	int		 i;
464 	struct tag	*t;
465 
466 	/* Push this tags onto the stack of open scopes. */
467 
468 	if ( ! (HTML_NOSTACK & htmltags[tag].flags)) {
469 		t = mandoc_malloc(sizeof(struct tag));
470 		t->tag = tag;
471 		t->next = h->tags.head;
472 		h->tags.head = t;
473 	} else
474 		t = NULL;
475 
476 	if ( ! (HTML_NOSPACE & h->flags))
477 		if ( ! (HTML_CLRLINE & htmltags[tag].flags)) {
478 			/* Manage keeps! */
479 			if ( ! (HTML_KEEP & h->flags)) {
480 				if (HTML_PREKEEP & h->flags)
481 					h->flags |= HTML_KEEP;
482 				putchar(' ');
483 			} else
484 				printf("&#160;");
485 		}
486 
487 	if ( ! (h->flags & HTML_NONOSPACE))
488 		h->flags &= ~HTML_NOSPACE;
489 	else
490 		h->flags |= HTML_NOSPACE;
491 
492 	/* Print out the tag name and attributes. */
493 
494 	printf("<%s", htmltags[tag].name);
495 	for (i = 0; i < sz; i++)
496 		print_attr(h, htmlattrs[p[i].key], p[i].val);
497 
498 	/* Add non-overridable attributes. */
499 
500 	if (TAG_HTML == tag && HTML_XHTML_1_0_STRICT == h->type) {
501 		print_attr(h, "xmlns", "http://www.w3.org/1999/xhtml");
502 		print_attr(h, "xml:lang", "en");
503 		print_attr(h, "lang", "en");
504 	}
505 
506 	/* Accommodate for XML "well-formed" singleton escaping. */
507 
508 	if (HTML_AUTOCLOSE & htmltags[tag].flags)
509 		switch (h->type) {
510 		case HTML_XHTML_1_0_STRICT:
511 			putchar('/');
512 			break;
513 		default:
514 			break;
515 		}
516 
517 	putchar('>');
518 
519 	h->flags |= HTML_NOSPACE;
520 
521 	if ((HTML_AUTOCLOSE | HTML_CLRLINE) & htmltags[tag].flags)
522 		putchar('\n');
523 
524 	return(t);
525 }
526 
527 static void
528 print_ctag(struct html *h, enum htmltag tag)
529 {
530 
531 	printf("</%s>", htmltags[tag].name);
532 	if (HTML_CLRLINE & htmltags[tag].flags) {
533 		h->flags |= HTML_NOSPACE;
534 		putchar('\n');
535 	}
536 }
537 
538 void
539 print_gen_decls(struct html *h)
540 {
541 	const char	*doctype;
542 	const char	*dtd;
543 	const char	*name;
544 
545 	switch (h->type) {
546 	case HTML_HTML_4_01_STRICT:
547 		name = "HTML";
548 		doctype = "-//W3C//DTD HTML 4.01//EN";
549 		dtd = "http://www.w3.org/TR/html4/strict.dtd";
550 		break;
551 	default:
552 		puts("<?xml version=\"1.0\" encoding=\"UTF-8\"?>");
553 		name = "html";
554 		doctype = "-//W3C//DTD XHTML 1.0 Strict//EN";
555 		dtd = "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd";
556 		break;
557 	}
558 
559 	printf("<!DOCTYPE %s PUBLIC \"%s\" \"%s\">\n",
560 	    name, doctype, dtd);
561 }
562 
563 void
564 print_text(struct html *h, const char *word)
565 {
566 
567 	if ( ! (HTML_NOSPACE & h->flags)) {
568 		/* Manage keeps! */
569 		if ( ! (HTML_KEEP & h->flags)) {
570 			if (HTML_PREKEEP & h->flags)
571 				h->flags |= HTML_KEEP;
572 			putchar(' ');
573 		} else
574 			printf("&#160;");
575 	}
576 
577 	assert(NULL == h->metaf);
578 	switch (h->metac) {
579 	case HTMLFONT_ITALIC:
580 		h->metaf = print_otag(h, TAG_I, 0, NULL);
581 		break;
582 	case HTMLFONT_BOLD:
583 		h->metaf = print_otag(h, TAG_B, 0, NULL);
584 		break;
585 	case HTMLFONT_BI:
586 		h->metaf = print_otag(h, TAG_B, 0, NULL);
587 		print_otag(h, TAG_I, 0, NULL);
588 		break;
589 	default:
590 		break;
591 	}
592 
593 	assert(word);
594 	if ( ! print_encode(h, word, 0)) {
595 		if ( ! (h->flags & HTML_NONOSPACE))
596 			h->flags &= ~HTML_NOSPACE;
597 	} else
598 		h->flags |= HTML_NOSPACE;
599 
600 	if (h->metaf) {
601 		print_tagq(h, h->metaf);
602 		h->metaf = NULL;
603 	}
604 
605 	h->flags &= ~HTML_IGNDELIM;
606 }
607 
608 void
609 print_tagq(struct html *h, const struct tag *until)
610 {
611 	struct tag	*tag;
612 
613 	while ((tag = h->tags.head) != NULL) {
614 		/*
615 		 * Remember to close out and nullify the current
616 		 * meta-font and table, if applicable.
617 		 */
618 		if (tag == h->metaf)
619 			h->metaf = NULL;
620 		if (tag == h->tblt)
621 			h->tblt = NULL;
622 		print_ctag(h, tag->tag);
623 		h->tags.head = tag->next;
624 		free(tag);
625 		if (until && tag == until)
626 			return;
627 	}
628 }
629 
630 void
631 print_stagq(struct html *h, const struct tag *suntil)
632 {
633 	struct tag	*tag;
634 
635 	while ((tag = h->tags.head) != NULL) {
636 		if (suntil && tag == suntil)
637 			return;
638 		/*
639 		 * Remember to close out and nullify the current
640 		 * meta-font and table, if applicable.
641 		 */
642 		if (tag == h->metaf)
643 			h->metaf = NULL;
644 		if (tag == h->tblt)
645 			h->tblt = NULL;
646 		print_ctag(h, tag->tag);
647 		h->tags.head = tag->next;
648 		free(tag);
649 	}
650 }
651 
652 void
653 bufinit(struct html *h)
654 {
655 
656 	h->buf[0] = '\0';
657 	h->buflen = 0;
658 }
659 
660 void
661 bufcat_style(struct html *h, const char *key, const char *val)
662 {
663 
664 	bufcat(h, key);
665 	bufcat(h, ":");
666 	bufcat(h, val);
667 	bufcat(h, ";");
668 }
669 
670 void
671 bufcat(struct html *h, const char *p)
672 {
673 
674 	/*
675 	 * XXX This is broken and not easy to fix.
676 	 * When using the -Oincludes option, buffmt_includes()
677 	 * may pass in strings overrunning BUFSIZ, causing a crash.
678 	 */
679 
680 	h->buflen = strlcat(h->buf, p, BUFSIZ);
681 	assert(h->buflen < BUFSIZ);
682 }
683 
684 void
685 bufcat_fmt(struct html *h, const char *fmt, ...)
686 {
687 	va_list		 ap;
688 
689 	va_start(ap, fmt);
690 	(void)vsnprintf(h->buf + (int)h->buflen,
691 	    BUFSIZ - h->buflen - 1, fmt, ap);
692 	va_end(ap);
693 	h->buflen = strlen(h->buf);
694 }
695 
696 static void
697 bufncat(struct html *h, const char *p, size_t sz)
698 {
699 
700 	assert(h->buflen + sz + 1 < BUFSIZ);
701 	strncat(h->buf, p, sz);
702 	h->buflen += sz;
703 }
704 
705 void
706 buffmt_includes(struct html *h, const char *name)
707 {
708 	const char	*p, *pp;
709 
710 	pp = h->base_includes;
711 
712 	bufinit(h);
713 	while (NULL != (p = strchr(pp, '%'))) {
714 		bufncat(h, pp, (size_t)(p - pp));
715 		switch (*(p + 1)) {
716 		case'I':
717 			bufcat(h, name);
718 			break;
719 		default:
720 			bufncat(h, p, 2);
721 			break;
722 		}
723 		pp = p + 2;
724 	}
725 	if (pp)
726 		bufcat(h, pp);
727 }
728 
729 void
730 buffmt_man(struct html *h, const char *name, const char *sec)
731 {
732 	const char	*p, *pp;
733 
734 	pp = h->base_man;
735 
736 	bufinit(h);
737 	while (NULL != (p = strchr(pp, '%'))) {
738 		bufncat(h, pp, (size_t)(p - pp));
739 		switch (*(p + 1)) {
740 		case 'S':
741 			bufcat(h, sec ? sec : "1");
742 			break;
743 		case 'N':
744 			bufcat_fmt(h, "%s", name);
745 			break;
746 		default:
747 			bufncat(h, p, 2);
748 			break;
749 		}
750 		pp = p + 2;
751 	}
752 	if (pp)
753 		bufcat(h, pp);
754 }
755 
756 void
757 bufcat_su(struct html *h, const char *p, const struct roffsu *su)
758 {
759 	double		 v;
760 
761 	v = su->scale;
762 	if (SCALE_MM == su->unit && 0.0 == (v /= 100.0))
763 		v = 1.0;
764 
765 	bufcat_fmt(h, "%s: %.2f%s;", p, v, roffscales[su->unit]);
766 }
767 
768 void
769 bufcat_id(struct html *h, const char *src)
770 {
771 
772 	/* Cf. <http://www.w3.org/TR/html4/types.html#h-6.2>. */
773 
774 	while ('\0' != *src)
775 		bufcat_fmt(h, "%.2x", *src++);
776 }
777