xref: /titanic_52/usr/src/cmd/mandoc/html.c (revision 263f549e5da8b32c4922f586afb365b8ae388a6c) 
1 /*	$Id: html.c,v 1.185 2015/01/21 20:33:25 schwarze Exp $ */
2 /*
3  * Copyright (c) 2008-2011, 2014 Kristaps Dzonsons <kristaps@bsd.lv>
4  * Copyright (c) 2011-2015 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 "config.h"
19 
20 #include <sys/types.h>
21 
22 #include <assert.h>
23 #include <ctype.h>
24 #include <stdarg.h>
25 #include <stdio.h>
26 #include <stdint.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <unistd.h>
30 
31 #include "mandoc.h"
32 #include "mandoc_aux.h"
33 #include "out.h"
34 #include "html.h"
35 #include "main.h"
36 
37 struct	htmldata {
38 	const char	 *name;
39 	int		  flags;
40 #define	HTML_CLRLINE	 (1 << 0)
41 #define	HTML_NOSTACK	 (1 << 1)
42 #define	HTML_AUTOCLOSE	 (1 << 2) /* Tag has auto-closure. */
43 };
44 
45 static	const struct htmldata htmltags[TAG_MAX] = {
46 	{"html",	HTML_CLRLINE}, /* TAG_HTML */
47 	{"head",	HTML_CLRLINE}, /* TAG_HEAD */
48 	{"body",	HTML_CLRLINE}, /* TAG_BODY */
49 	{"meta",	HTML_CLRLINE | HTML_NOSTACK | HTML_AUTOCLOSE}, /* TAG_META */
50 	{"title",	HTML_CLRLINE}, /* TAG_TITLE */
51 	{"div",		HTML_CLRLINE}, /* TAG_DIV */
52 	{"h1",		0}, /* TAG_H1 */
53 	{"h2",		0}, /* TAG_H2 */
54 	{"span",	0}, /* TAG_SPAN */
55 	{"link",	HTML_CLRLINE | HTML_NOSTACK | HTML_AUTOCLOSE}, /* TAG_LINK */
56 	{"br",		HTML_CLRLINE | HTML_NOSTACK | HTML_AUTOCLOSE}, /* TAG_BR */
57 	{"a",		0}, /* TAG_A */
58 	{"table",	HTML_CLRLINE}, /* TAG_TABLE */
59 	{"tbody",	HTML_CLRLINE}, /* TAG_TBODY */
60 	{"col",		HTML_CLRLINE | HTML_NOSTACK | HTML_AUTOCLOSE}, /* TAG_COL */
61 	{"tr",		HTML_CLRLINE}, /* TAG_TR */
62 	{"td",		HTML_CLRLINE}, /* TAG_TD */
63 	{"li",		HTML_CLRLINE}, /* TAG_LI */
64 	{"ul",		HTML_CLRLINE}, /* TAG_UL */
65 	{"ol",		HTML_CLRLINE}, /* TAG_OL */
66 	{"dl",		HTML_CLRLINE}, /* TAG_DL */
67 	{"dt",		HTML_CLRLINE}, /* TAG_DT */
68 	{"dd",		HTML_CLRLINE}, /* TAG_DD */
69 	{"blockquote",	HTML_CLRLINE}, /* TAG_BLOCKQUOTE */
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 	{"style",	HTML_CLRLINE}, /* TAG_STYLE */
76 	{"math",	HTML_CLRLINE}, /* TAG_MATH */
77 	{"mrow",	0}, /* TAG_MROW */
78 	{"mi",		0}, /* TAG_MI */
79 	{"mo",		0}, /* TAG_MO */
80 	{"msup",	0}, /* TAG_MSUP */
81 	{"msub",	0}, /* TAG_MSUB */
82 	{"msubsup",	0}, /* TAG_MSUBSUP */
83 	{"mfrac",	0}, /* TAG_MFRAC */
84 	{"msqrt",	0}, /* TAG_MSQRT */
85 	{"mfenced",	0}, /* TAG_MFENCED */
86 	{"mtable",	0}, /* TAG_MTABLE */
87 	{"mtr",		0}, /* TAG_MTR */
88 	{"mtd",		0}, /* TAG_MTD */
89 	{"munderover",	0}, /* TAG_MUNDEROVER */
90 	{"munder",	0}, /* TAG_MUNDER*/
91 	{"mover",	0}, /* TAG_MOVER*/
92 };
93 
94 static	const char	*const htmlattrs[ATTR_MAX] = {
95 	"name", /* ATTR_NAME */
96 	"rel", /* ATTR_REL */
97 	"href", /* ATTR_HREF */
98 	"type", /* ATTR_TYPE */
99 	"media", /* ATTR_MEDIA */
100 	"class", /* ATTR_CLASS */
101 	"style", /* ATTR_STYLE */
102 	"id", /* ATTR_ID */
103 	"colspan", /* ATTR_COLSPAN */
104 	"charset", /* ATTR_CHARSET */
105 	"open", /* ATTR_OPEN */
106 	"close", /* ATTR_CLOSE */
107 	"mathvariant", /* ATTR_MATHVARIANT */
108 };
109 
110 static	const char	*const roffscales[SCALE_MAX] = {
111 	"cm", /* SCALE_CM */
112 	"in", /* SCALE_IN */
113 	"pc", /* SCALE_PC */
114 	"pt", /* SCALE_PT */
115 	"em", /* SCALE_EM */
116 	"em", /* SCALE_MM */
117 	"ex", /* SCALE_EN */
118 	"ex", /* SCALE_BU */
119 	"em", /* SCALE_VS */
120 	"ex", /* SCALE_FS */
121 };
122 
123 static	void	 bufncat(struct html *, const char *, size_t);
124 static	void	 print_ctag(struct html *, struct tag *);
125 static	int	 print_escape(char);
126 static	int	 print_encode(struct html *, const char *, int);
127 static	void	 print_metaf(struct html *, enum mandoc_esc);
128 static	void	 print_attr(struct html *, const char *, const char *);
129 
130 
131 void *
132 html_alloc(const struct mchars *mchars, char *outopts)
133 {
134 	struct html	*h;
135 	const char	*toks[5];
136 	char		*v;
137 
138 	toks[0] = "style";
139 	toks[1] = "man";
140 	toks[2] = "includes";
141 	toks[3] = "fragment";
142 	toks[4] = NULL;
143 
144 	h = mandoc_calloc(1, sizeof(struct html));
145 
146 	h->tags.head = NULL;
147 	h->symtab = mchars;
148 
149 	while (outopts && *outopts)
150 		switch (getsubopt(&outopts, UNCONST(toks), &v)) {
151 		case 0:
152 			h->style = v;
153 			break;
154 		case 1:
155 			h->base_man = v;
156 			break;
157 		case 2:
158 			h->base_includes = v;
159 			break;
160 		case 3:
161 			h->oflags |= HTML_FRAGMENT;
162 			break;
163 		default:
164 			break;
165 		}
166 
167 	return(h);
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 	free(h);
184 }
185 
186 void
187 print_gen_head(struct html *h)
188 {
189 	struct htmlpair	 tag[4];
190 	struct tag	*t;
191 
192 	tag[0].key = ATTR_CHARSET;
193 	tag[0].val = "utf-8";
194 	print_otag(h, TAG_META, 1, tag);
195 
196 	/*
197 	 * Print a default style-sheet.
198 	 */
199 	t = print_otag(h, TAG_STYLE, 0, NULL);
200 	print_text(h, "table.head, table.foot { width: 100%; }\n"
201 	      "td.head-rtitle, td.foot-os { text-align: right; }\n"
202 	      "td.head-vol { text-align: center; }\n"
203 	      "table.foot td { width: 50%; }\n"
204 	      "table.head td { width: 33%; }\n"
205 	      "div.spacer { margin: 1em 0; }\n");
206 	print_tagq(h, t);
207 
208 	if (h->style) {
209 		tag[0].key = ATTR_REL;
210 		tag[0].val = "stylesheet";
211 		tag[1].key = ATTR_HREF;
212 		tag[1].val = h->style;
213 		tag[2].key = ATTR_TYPE;
214 		tag[2].val = "text/css";
215 		tag[3].key = ATTR_MEDIA;
216 		tag[3].val = "all";
217 		print_otag(h, TAG_LINK, 4, tag);
218 	}
219 }
220 
221 static void
222 print_metaf(struct html *h, enum mandoc_esc deco)
223 {
224 	enum htmlfont	 font;
225 
226 	switch (deco) {
227 	case ESCAPE_FONTPREV:
228 		font = h->metal;
229 		break;
230 	case ESCAPE_FONTITALIC:
231 		font = HTMLFONT_ITALIC;
232 		break;
233 	case ESCAPE_FONTBOLD:
234 		font = HTMLFONT_BOLD;
235 		break;
236 	case ESCAPE_FONTBI:
237 		font = HTMLFONT_BI;
238 		break;
239 	case ESCAPE_FONT:
240 		/* FALLTHROUGH */
241 	case ESCAPE_FONTROMAN:
242 		font = HTMLFONT_NONE;
243 		break;
244 	default:
245 		abort();
246 		/* NOTREACHED */
247 	}
248 
249 	if (h->metaf) {
250 		print_tagq(h, h->metaf);
251 		h->metaf = NULL;
252 	}
253 
254 	h->metal = h->metac;
255 	h->metac = font;
256 
257 	switch (font) {
258 	case HTMLFONT_ITALIC:
259 		h->metaf = print_otag(h, TAG_I, 0, NULL);
260 		break;
261 	case HTMLFONT_BOLD:
262 		h->metaf = print_otag(h, TAG_B, 0, NULL);
263 		break;
264 	case HTMLFONT_BI:
265 		h->metaf = print_otag(h, TAG_B, 0, NULL);
266 		print_otag(h, TAG_I, 0, NULL);
267 		break;
268 	default:
269 		break;
270 	}
271 }
272 
273 int
274 html_strlen(const char *cp)
275 {
276 	size_t		 rsz;
277 	int		 skip, sz;
278 
279 	/*
280 	 * Account for escaped sequences within string length
281 	 * calculations.  This follows the logic in term_strlen() as we
282 	 * must calculate the width of produced strings.
283 	 * Assume that characters are always width of "1".  This is
284 	 * hacky, but it gets the job done for approximation of widths.
285 	 */
286 
287 	sz = 0;
288 	skip = 0;
289 	while (1) {
290 		rsz = strcspn(cp, "\\");
291 		if (rsz) {
292 			cp += rsz;
293 			if (skip) {
294 				skip = 0;
295 				rsz--;
296 			}
297 			sz += rsz;
298 		}
299 		if ('\0' == *cp)
300 			break;
301 		cp++;
302 		switch (mandoc_escape(&cp, NULL, NULL)) {
303 		case ESCAPE_ERROR:
304 			return(sz);
305 		case ESCAPE_UNICODE:
306 			/* FALLTHROUGH */
307 		case ESCAPE_NUMBERED:
308 			/* FALLTHROUGH */
309 		case ESCAPE_SPECIAL:
310 			/* FALLTHROUGH */
311 		case ESCAPE_OVERSTRIKE:
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 			break;
424 		case ESCAPE_NUMBERED:
425 			c = mchars_num2char(seq, len);
426 			if (c < 0)
427 				continue;
428 			break;
429 		case ESCAPE_SPECIAL:
430 			c = mchars_spec2cp(h->symtab, seq, len);
431 			if (c <= 0)
432 				continue;
433 			break;
434 		case ESCAPE_NOSPACE:
435 			if ('\0' == *p)
436 				nospace = 1;
437 			continue;
438 		case ESCAPE_OVERSTRIKE:
439 			if (len == 0)
440 				continue;
441 			c = seq[len - 1];
442 			break;
443 		default:
444 			continue;
445 		}
446 		if ((c < 0x20 && c != 0x09) ||
447 		    (c > 0x7E && c < 0xA0))
448 			c = 0xFFFD;
449 		if (c > 0x7E)
450 			printf("&#%d;", c);
451 		else if ( ! print_escape(c))
452 			putchar(c);
453 	}
454 
455 	return(nospace);
456 }
457 
458 static void
459 print_attr(struct html *h, const char *key, const char *val)
460 {
461 	printf(" %s=\"", key);
462 	(void)print_encode(h, val, 1);
463 	putchar('\"');
464 }
465 
466 struct tag *
467 print_otag(struct html *h, enum htmltag tag,
468 		int sz, const struct htmlpair *p)
469 {
470 	int		 i;
471 	struct tag	*t;
472 
473 	/* Push this tags onto the stack of open scopes. */
474 
475 	if ( ! (HTML_NOSTACK & htmltags[tag].flags)) {
476 		t = mandoc_malloc(sizeof(struct tag));
477 		t->tag = tag;
478 		t->next = h->tags.head;
479 		h->tags.head = t;
480 	} else
481 		t = NULL;
482 
483 	if ( ! (HTML_NOSPACE & h->flags))
484 		if ( ! (HTML_CLRLINE & htmltags[tag].flags)) {
485 			/* Manage keeps! */
486 			if ( ! (HTML_KEEP & h->flags)) {
487 				if (HTML_PREKEEP & h->flags)
488 					h->flags |= HTML_KEEP;
489 				putchar(' ');
490 			} else
491 				printf("&#160;");
492 		}
493 
494 	if ( ! (h->flags & HTML_NONOSPACE))
495 		h->flags &= ~HTML_NOSPACE;
496 	else
497 		h->flags |= HTML_NOSPACE;
498 
499 	/* Print out the tag name and attributes. */
500 
501 	printf("<%s", htmltags[tag].name);
502 	for (i = 0; i < sz; i++)
503 		print_attr(h, htmlattrs[p[i].key], p[i].val);
504 
505 	/* Accommodate for "well-formed" singleton escaping. */
506 
507 	if (HTML_AUTOCLOSE & htmltags[tag].flags)
508 		putchar('/');
509 
510 	putchar('>');
511 
512 	h->flags |= HTML_NOSPACE;
513 
514 	if ((HTML_AUTOCLOSE | HTML_CLRLINE) & htmltags[tag].flags)
515 		putchar('\n');
516 
517 	return(t);
518 }
519 
520 static void
521 print_ctag(struct html *h, struct tag *tag)
522 {
523 
524 	/*
525 	 * Remember to close out and nullify the current
526 	 * meta-font and table, if applicable.
527 	 */
528 	if (tag == h->metaf)
529 		h->metaf = NULL;
530 	if (tag == h->tblt)
531 		h->tblt = NULL;
532 
533 	printf("</%s>", htmltags[tag->tag].name);
534 	if (HTML_CLRLINE & htmltags[tag->tag].flags) {
535 		h->flags |= HTML_NOSPACE;
536 		putchar('\n');
537 	}
538 
539 	h->tags.head = tag->next;
540 	free(tag);
541 }
542 
543 void
544 print_gen_decls(struct html *h)
545 {
546 
547 	puts("<!DOCTYPE html>");
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 		h->flags &= ~HTML_NONEWLINE;
585 	} else
586 		h->flags |= HTML_NOSPACE | HTML_NONEWLINE;
587 
588 	if (h->metaf) {
589 		print_tagq(h, h->metaf);
590 		h->metaf = NULL;
591 	}
592 
593 	h->flags &= ~HTML_IGNDELIM;
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 		print_ctag(h, tag);
603 		if (until && tag == until)
604 			return;
605 	}
606 }
607 
608 void
609 print_stagq(struct html *h, const struct tag *suntil)
610 {
611 	struct tag	*tag;
612 
613 	while ((tag = h->tags.head) != NULL) {
614 		if (suntil && tag == suntil)
615 			return;
616 		print_ctag(h, tag);
617 	}
618 }
619 
620 void
621 print_paragraph(struct html *h)
622 {
623 	struct tag	*t;
624 	struct htmlpair	 tag;
625 
626 	PAIR_CLASS_INIT(&tag, "spacer");
627 	t = print_otag(h, TAG_DIV, 1, &tag);
628 	print_tagq(h, t);
629 }
630 
631 
632 void
633 bufinit(struct html *h)
634 {
635 
636 	h->buf[0] = '\0';
637 	h->buflen = 0;
638 }
639 
640 void
641 bufcat_style(struct html *h, const char *key, const char *val)
642 {
643 
644 	bufcat(h, key);
645 	bufcat(h, ":");
646 	bufcat(h, val);
647 	bufcat(h, ";");
648 }
649 
650 void
651 bufcat(struct html *h, const char *p)
652 {
653 
654 	/*
655 	 * XXX This is broken and not easy to fix.
656 	 * When using the -Oincludes option, buffmt_includes()
657 	 * may pass in strings overrunning BUFSIZ, causing a crash.
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, const char *name, const char *sec)
711 {
712 	const char	*p, *pp;
713 
714 	pp = h->base_man;
715 
716 	bufinit(h);
717 	while (NULL != (p = strchr(pp, '%'))) {
718 		bufncat(h, pp, (size_t)(p - pp));
719 		switch (*(p + 1)) {
720 		case 'S':
721 			bufcat(h, sec ? sec : "1");
722 			break;
723 		case 'N':
724 			bufcat_fmt(h, "%s", name);
725 			break;
726 		default:
727 			bufncat(h, p, 2);
728 			break;
729 		}
730 		pp = p + 2;
731 	}
732 	if (pp)
733 		bufcat(h, pp);
734 }
735 
736 void
737 bufcat_su(struct html *h, const char *p, const struct roffsu *su)
738 {
739 	double		 v;
740 
741 	v = su->scale;
742 	if (SCALE_MM == su->unit && 0.0 == (v /= 100.0))
743 		v = 1.0;
744 	else if (SCALE_BU == su->unit)
745 		v /= 24.0;
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