xref: /openbsd-src/usr.bin/mandoc/html.c (revision 50b7afb2c2c0993b0894d4e34bf857cb13ed9c80) 
1 /*	$Id: html.c,v 1.36 2014/04/23 16:07:06 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 
115 static void *
116 ml_alloc(char *outopts, enum htmltype type)
117 {
118 	struct html	*h;
119 	const char	*toks[5];
120 	char		*v;
121 
122 	toks[0] = "style";
123 	toks[1] = "man";
124 	toks[2] = "includes";
125 	toks[3] = "fragment";
126 	toks[4] = NULL;
127 
128 	h = mandoc_calloc(1, sizeof(struct html));
129 
130 	h->type = type;
131 	h->tags.head = NULL;
132 	h->symtab = mchars_alloc();
133 
134 	while (outopts && *outopts)
135 		switch (getsubopt(&outopts, UNCONST(toks), &v)) {
136 		case 0:
137 			h->style = v;
138 			break;
139 		case 1:
140 			h->base_man = v;
141 			break;
142 		case 2:
143 			h->base_includes = v;
144 			break;
145 		case 3:
146 			h->oflags |= HTML_FRAGMENT;
147 			break;
148 		default:
149 			break;
150 		}
151 
152 	return(h);
153 }
154 
155 void *
156 html_alloc(char *outopts)
157 {
158 
159 	return(ml_alloc(outopts, HTML_HTML_4_01_STRICT));
160 }
161 
162 void *
163 xhtml_alloc(char *outopts)
164 {
165 
166 	return(ml_alloc(outopts, HTML_XHTML_1_0_STRICT));
167 }
168 
169 void
170 html_free(void *p)
171 {
172 	struct tag	*tag;
173 	struct html	*h;
174 
175 	h = (struct html *)p;
176 
177 	while ((tag = h->tags.head) != NULL) {
178 		h->tags.head = tag->next;
179 		free(tag);
180 	}
181 
182 	if (h->symtab)
183 		mchars_free(h->symtab);
184 
185 	free(h);
186 }
187 
188 void
189 print_gen_head(struct html *h)
190 {
191 	struct htmlpair	 tag[4];
192 
193 	tag[0].key = ATTR_HTTPEQUIV;
194 	tag[0].val = "Content-Type";
195 	tag[1].key = ATTR_CONTENT;
196 	tag[1].val = "text/html; charset=utf-8";
197 	print_otag(h, TAG_META, 2, tag);
198 
199 	tag[0].key = ATTR_NAME;
200 	tag[0].val = "resource-type";
201 	tag[1].key = ATTR_CONTENT;
202 	tag[1].val = "document";
203 	print_otag(h, TAG_META, 2, tag);
204 
205 	if (h->style) {
206 		tag[0].key = ATTR_REL;
207 		tag[0].val = "stylesheet";
208 		tag[1].key = ATTR_HREF;
209 		tag[1].val = h->style;
210 		tag[2].key = ATTR_TYPE;
211 		tag[2].val = "text/css";
212 		tag[3].key = ATTR_MEDIA;
213 		tag[3].val = "all";
214 		print_otag(h, TAG_LINK, 4, tag);
215 	}
216 }
217 
218 static void
219 print_metaf(struct html *h, enum mandoc_esc deco)
220 {
221 	enum htmlfont	 font;
222 
223 	switch (deco) {
224 	case ESCAPE_FONTPREV:
225 		font = h->metal;
226 		break;
227 	case ESCAPE_FONTITALIC:
228 		font = HTMLFONT_ITALIC;
229 		break;
230 	case ESCAPE_FONTBOLD:
231 		font = HTMLFONT_BOLD;
232 		break;
233 	case ESCAPE_FONTBI:
234 		font = HTMLFONT_BI;
235 		break;
236 	case ESCAPE_FONT:
237 		/* FALLTHROUGH */
238 	case ESCAPE_FONTROMAN:
239 		font = HTMLFONT_NONE;
240 		break;
241 	default:
242 		abort();
243 		/* NOTREACHED */
244 	}
245 
246 	if (h->metaf) {
247 		print_tagq(h, h->metaf);
248 		h->metaf = NULL;
249 	}
250 
251 	h->metal = h->metac;
252 	h->metac = font;
253 
254 	switch (font) {
255 	case HTMLFONT_ITALIC:
256 		h->metaf = print_otag(h, TAG_I, 0, NULL);
257 		break;
258 	case HTMLFONT_BOLD:
259 		h->metaf = print_otag(h, TAG_B, 0, NULL);
260 		break;
261 	case HTMLFONT_BI:
262 		h->metaf = print_otag(h, TAG_B, 0, NULL);
263 		print_otag(h, TAG_I, 0, NULL);
264 		break;
265 	default:
266 		break;
267 	}
268 }
269 
270 int
271 html_strlen(const char *cp)
272 {
273 	size_t		 rsz;
274 	int		 skip, sz;
275 
276 	/*
277 	 * Account for escaped sequences within string length
278 	 * calculations.  This follows the logic in term_strlen() as we
279 	 * must calculate the width of produced strings.
280 	 * Assume that characters are always width of "1".  This is
281 	 * hacky, but it gets the job done for approximation of widths.
282 	 */
283 
284 	sz = 0;
285 	skip = 0;
286 	while (1) {
287 		rsz = strcspn(cp, "\\");
288 		if (rsz) {
289 			cp += rsz;
290 			if (skip) {
291 				skip = 0;
292 				rsz--;
293 			}
294 			sz += rsz;
295 		}
296 		if ('\0' == *cp)
297 			break;
298 		cp++;
299 		switch (mandoc_escape(&cp, NULL, NULL)) {
300 		case ESCAPE_ERROR:
301 			return(sz);
302 		case ESCAPE_UNICODE:
303 			/* FALLTHROUGH */
304 		case ESCAPE_NUMBERED:
305 			/* FALLTHROUGH */
306 		case ESCAPE_SPECIAL:
307 			if (skip)
308 				skip = 0;
309 			else
310 				sz++;
311 			break;
312 		case ESCAPE_SKIPCHAR:
313 			skip = 1;
314 			break;
315 		default:
316 			break;
317 		}
318 	}
319 	return(sz);
320 }
321 
322 static int
323 print_encode(struct html *h, const char *p, int norecurse)
324 {
325 	size_t		 sz;
326 	int		 c, len, nospace;
327 	const char	*seq;
328 	enum mandoc_esc	 esc;
329 	static const char rejs[8] = { '\\', '<', '>', '&',
330 		ASCII_NBRSP, ASCII_HYPH, ASCII_BREAK, '\0' };
331 
332 	nospace = 0;
333 
334 	while ('\0' != *p) {
335 		if (HTML_SKIPCHAR & h->flags && '\\' != *p) {
336 			h->flags &= ~HTML_SKIPCHAR;
337 			p++;
338 			continue;
339 		}
340 
341 		sz = strcspn(p, rejs);
342 
343 		fwrite(p, 1, sz, stdout);
344 		p += (int)sz;
345 
346 		if ('\0' == *p)
347 			break;
348 
349 		switch (*p++) {
350 		case '<':
351 			printf("&lt;");
352 			continue;
353 		case '>':
354 			printf("&gt;");
355 			continue;
356 		case '&':
357 			printf("&amp;");
358 			continue;
359 		case ASCII_NBRSP:
360 			putchar('-');
361 			continue;
362 		case ASCII_HYPH:
363 			putchar('-');
364 			/* FALLTHROUGH */
365 		case ASCII_BREAK:
366 			continue;
367 		default:
368 			break;
369 		}
370 
371 		esc = mandoc_escape(&p, &seq, &len);
372 		if (ESCAPE_ERROR == esc)
373 			break;
374 
375 		switch (esc) {
376 		case ESCAPE_FONT:
377 			/* FALLTHROUGH */
378 		case ESCAPE_FONTPREV:
379 			/* FALLTHROUGH */
380 		case ESCAPE_FONTBOLD:
381 			/* FALLTHROUGH */
382 		case ESCAPE_FONTITALIC:
383 			/* FALLTHROUGH */
384 		case ESCAPE_FONTBI:
385 			/* FALLTHROUGH */
386 		case ESCAPE_FONTROMAN:
387 			if (0 == norecurse)
388 				print_metaf(h, esc);
389 			continue;
390 		case ESCAPE_SKIPCHAR:
391 			h->flags |= HTML_SKIPCHAR;
392 			continue;
393 		default:
394 			break;
395 		}
396 
397 		if (h->flags & HTML_SKIPCHAR) {
398 			h->flags &= ~HTML_SKIPCHAR;
399 			continue;
400 		}
401 
402 		switch (esc) {
403 		case ESCAPE_UNICODE:
404 			/* Skip passed "u" header. */
405 			c = mchars_num2uc(seq + 1, len - 1);
406 			if ('\0' != c)
407 				printf("&#x%x;", c);
408 			break;
409 		case ESCAPE_NUMBERED:
410 			c = mchars_num2char(seq, len);
411 			if ('\0' != c)
412 				putchar(c);
413 			break;
414 		case ESCAPE_SPECIAL:
415 			c = mchars_spec2cp(h->symtab, seq, len);
416 			if (c > 0)
417 				printf("&#%d;", c);
418 			else if (-1 == c && 1 == len)
419 				putchar((int)*seq);
420 			break;
421 		case ESCAPE_NOSPACE:
422 			if ('\0' == *p)
423 				nospace = 1;
424 			break;
425 		default:
426 			break;
427 		}
428 	}
429 
430 	return(nospace);
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 struct tag *
442 print_otag(struct html *h, enum htmltag tag,
443 		int sz, const struct htmlpair *p)
444 {
445 	int		 i;
446 	struct tag	*t;
447 
448 	/* Push this tags onto the stack of open scopes. */
449 
450 	if ( ! (HTML_NOSTACK & htmltags[tag].flags)) {
451 		t = mandoc_malloc(sizeof(struct tag));
452 		t->tag = tag;
453 		t->next = h->tags.head;
454 		h->tags.head = t;
455 	} else
456 		t = NULL;
457 
458 	if ( ! (HTML_NOSPACE & h->flags))
459 		if ( ! (HTML_CLRLINE & htmltags[tag].flags)) {
460 			/* Manage keeps! */
461 			if ( ! (HTML_KEEP & h->flags)) {
462 				if (HTML_PREKEEP & h->flags)
463 					h->flags |= HTML_KEEP;
464 				putchar(' ');
465 			} else
466 				printf("&#160;");
467 		}
468 
469 	if ( ! (h->flags & HTML_NONOSPACE))
470 		h->flags &= ~HTML_NOSPACE;
471 	else
472 		h->flags |= HTML_NOSPACE;
473 
474 	/* Print out the tag name and attributes. */
475 
476 	printf("<%s", htmltags[tag].name);
477 	for (i = 0; i < sz; i++)
478 		print_attr(h, htmlattrs[p[i].key], p[i].val);
479 
480 	/* Add non-overridable attributes. */
481 
482 	if (TAG_HTML == tag && HTML_XHTML_1_0_STRICT == h->type) {
483 		print_attr(h, "xmlns", "http://www.w3.org/1999/xhtml");
484 		print_attr(h, "xml:lang", "en");
485 		print_attr(h, "lang", "en");
486 	}
487 
488 	/* Accommodate for XML "well-formed" singleton escaping. */
489 
490 	if (HTML_AUTOCLOSE & htmltags[tag].flags)
491 		switch (h->type) {
492 		case HTML_XHTML_1_0_STRICT:
493 			putchar('/');
494 			break;
495 		default:
496 			break;
497 		}
498 
499 	putchar('>');
500 
501 	h->flags |= HTML_NOSPACE;
502 
503 	if ((HTML_AUTOCLOSE | HTML_CLRLINE) & htmltags[tag].flags)
504 		putchar('\n');
505 
506 	return(t);
507 }
508 
509 static void
510 print_ctag(struct html *h, enum htmltag tag)
511 {
512 
513 	printf("</%s>", htmltags[tag].name);
514 	if (HTML_CLRLINE & htmltags[tag].flags) {
515 		h->flags |= HTML_NOSPACE;
516 		putchar('\n');
517 	}
518 }
519 
520 void
521 print_gen_decls(struct html *h)
522 {
523 	const char	*doctype;
524 	const char	*dtd;
525 	const char	*name;
526 
527 	switch (h->type) {
528 	case HTML_HTML_4_01_STRICT:
529 		name = "HTML";
530 		doctype = "-//W3C//DTD HTML 4.01//EN";
531 		dtd = "http://www.w3.org/TR/html4/strict.dtd";
532 		break;
533 	default:
534 		puts("<?xml version=\"1.0\" encoding=\"UTF-8\"?>");
535 		name = "html";
536 		doctype = "-//W3C//DTD XHTML 1.0 Strict//EN";
537 		dtd = "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd";
538 		break;
539 	}
540 
541 	printf("<!DOCTYPE %s PUBLIC \"%s\" \"%s\">\n",
542 	    name, doctype, dtd);
543 }
544 
545 void
546 print_text(struct html *h, const char *word)
547 {
548 
549 	if ( ! (HTML_NOSPACE & h->flags)) {
550 		/* Manage keeps! */
551 		if ( ! (HTML_KEEP & h->flags)) {
552 			if (HTML_PREKEEP & h->flags)
553 				h->flags |= HTML_KEEP;
554 			putchar(' ');
555 		} else
556 			printf("&#160;");
557 	}
558 
559 	assert(NULL == h->metaf);
560 	switch (h->metac) {
561 	case HTMLFONT_ITALIC:
562 		h->metaf = print_otag(h, TAG_I, 0, NULL);
563 		break;
564 	case HTMLFONT_BOLD:
565 		h->metaf = print_otag(h, TAG_B, 0, NULL);
566 		break;
567 	case HTMLFONT_BI:
568 		h->metaf = print_otag(h, TAG_B, 0, NULL);
569 		print_otag(h, TAG_I, 0, NULL);
570 		break;
571 	default:
572 		break;
573 	}
574 
575 	assert(word);
576 	if ( ! print_encode(h, word, 0)) {
577 		if ( ! (h->flags & HTML_NONOSPACE))
578 			h->flags &= ~HTML_NOSPACE;
579 	} else
580 		h->flags |= HTML_NOSPACE;
581 
582 	if (h->metaf) {
583 		print_tagq(h, h->metaf);
584 		h->metaf = NULL;
585 	}
586 
587 	h->flags &= ~HTML_IGNDELIM;
588 }
589 
590 void
591 print_tagq(struct html *h, const struct tag *until)
592 {
593 	struct tag	*tag;
594 
595 	while ((tag = h->tags.head) != NULL) {
596 		/*
597 		 * Remember to close out and nullify the current
598 		 * meta-font and table, if applicable.
599 		 */
600 		if (tag == h->metaf)
601 			h->metaf = NULL;
602 		if (tag == h->tblt)
603 			h->tblt = NULL;
604 		print_ctag(h, tag->tag);
605 		h->tags.head = tag->next;
606 		free(tag);
607 		if (until && tag == until)
608 			return;
609 	}
610 }
611 
612 void
613 print_stagq(struct html *h, const struct tag *suntil)
614 {
615 	struct tag	*tag;
616 
617 	while ((tag = h->tags.head) != NULL) {
618 		if (suntil && tag == suntil)
619 			return;
620 		/*
621 		 * Remember to close out and nullify the current
622 		 * meta-font and table, if applicable.
623 		 */
624 		if (tag == h->metaf)
625 			h->metaf = NULL;
626 		if (tag == h->tblt)
627 			h->tblt = NULL;
628 		print_ctag(h, tag->tag);
629 		h->tags.head = tag->next;
630 		free(tag);
631 	}
632 }
633 
634 void
635 bufinit(struct html *h)
636 {
637 
638 	h->buf[0] = '\0';
639 	h->buflen = 0;
640 }
641 
642 void
643 bufcat_style(struct html *h, const char *key, const char *val)
644 {
645 
646 	bufcat(h, key);
647 	bufcat(h, ":");
648 	bufcat(h, val);
649 	bufcat(h, ";");
650 }
651 
652 void
653 bufcat(struct html *h, const char *p)
654 {
655 
656 	/*
657 	 * XXX This is broken and not easy to fix.
658 	 * When using the -Oincludes option, buffmt_includes()
659 	 * may pass in strings overrunning BUFSIZ, causing a crash.
660 	 */
661 
662 	h->buflen = strlcat(h->buf, p, BUFSIZ);
663 	assert(h->buflen < BUFSIZ);
664 }
665 
666 void
667 bufcat_fmt(struct html *h, const char *fmt, ...)
668 {
669 	va_list		 ap;
670 
671 	va_start(ap, fmt);
672 	(void)vsnprintf(h->buf + (int)h->buflen,
673 	    BUFSIZ - h->buflen - 1, fmt, ap);
674 	va_end(ap);
675 	h->buflen = strlen(h->buf);
676 }
677 
678 static void
679 bufncat(struct html *h, const char *p, size_t sz)
680 {
681 
682 	assert(h->buflen + sz + 1 < BUFSIZ);
683 	strncat(h->buf, p, sz);
684 	h->buflen += sz;
685 }
686 
687 void
688 buffmt_includes(struct html *h, const char *name)
689 {
690 	const char	*p, *pp;
691 
692 	pp = h->base_includes;
693 
694 	bufinit(h);
695 	while (NULL != (p = strchr(pp, '%'))) {
696 		bufncat(h, pp, (size_t)(p - pp));
697 		switch (*(p + 1)) {
698 		case'I':
699 			bufcat(h, name);
700 			break;
701 		default:
702 			bufncat(h, p, 2);
703 			break;
704 		}
705 		pp = p + 2;
706 	}
707 	if (pp)
708 		bufcat(h, pp);
709 }
710 
711 void
712 buffmt_man(struct html *h, const char *name, const char *sec)
713 {
714 	const char	*p, *pp;
715 
716 	pp = h->base_man;
717 
718 	bufinit(h);
719 	while (NULL != (p = strchr(pp, '%'))) {
720 		bufncat(h, pp, (size_t)(p - pp));
721 		switch (*(p + 1)) {
722 		case 'S':
723 			bufcat(h, sec ? sec : "1");
724 			break;
725 		case 'N':
726 			bufcat_fmt(h, "%s", name);
727 			break;
728 		default:
729 			bufncat(h, p, 2);
730 			break;
731 		}
732 		pp = p + 2;
733 	}
734 	if (pp)
735 		bufcat(h, pp);
736 }
737 
738 void
739 bufcat_su(struct html *h, const char *p, const struct roffsu *su)
740 {
741 	double		 v;
742 
743 	v = su->scale;
744 	if (SCALE_MM == su->unit && 0.0 == (v /= 100.0))
745 		v = 1.0;
746 
747 	bufcat_fmt(h, "%s: %.2f%s;", p, v, roffscales[su->unit]);
748 }
749 
750 void
751 bufcat_id(struct html *h, const char *src)
752 {
753 
754 	/* Cf. <http://www.w3.org/TR/html4/types.html#h-6.2>. */
755 
756 	while ('\0' != *src)
757 		bufcat_fmt(h, "%.2x", *src++);
758 }
759