html.c

   1 /*      $Id: html.c,v 1.139 2011/05/15 15:47:46 kristaps Exp $ */
   2 /*
   3  * Copyright (c) 2008, 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
   4  * Copyright (c) 2011 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  void              print_num(struct html *, const char *, size_t);
  98 static  void              print_spec(struct html *, const char *, size_t);
  99 static  void              print_res(struct html *, const char *, size_t);
 100 static  void              print_ctag(struct html *, enum htmltag);
 101 static  void              print_doctype(struct html *);
 102 static  void              print_xmltype(struct html *);
 103 static  int               print_encode(struct html *, const char *, int);
 104 static  void              print_metaf(struct html *, enum mandoc_esc);
 105 static  void              print_attr(struct html *,
 106                                 const char *, const char *);
 107 static  void             *ml_alloc(char *, enum htmltype);
 108
 109
 110 static void *
 111 ml_alloc(char *outopts, enum htmltype type)
 112 {
 113         struct html     *h;
 114         const char      *toks[4];
 115         char            *v;
 116
 117         toks[0] = "style";
 118         toks[1] = "man";
 119         toks[2] = "includes";
 120         toks[3] = NULL;
 121
 122         h = mandoc_calloc(1, sizeof(struct html));
 123
 124         h->type = type;
 125         h->tags.head = NULL;
 126         h->symtab = mchars_alloc();
 127
 128         while (outopts && *outopts)
 129                 switch (getsubopt(&outopts, UNCONST(toks), &v)) {
 130                 case (0):
 131                         h->style = v;
 132                         break;
 133                 case (1):
 134                         h->base_man = v;
 135                         break;
 136                 case (2):
 137                         h->base_includes = v;
 138                         break;
 139                 default:
 140                         break;
 141                 }
 142
 143         return(h);
 144 }
 145
 146 void *
 147 html_alloc(char *outopts)
 148 {
 149
 150         return(ml_alloc(outopts, HTML_HTML_4_01_STRICT));
 151 }
 152
 153
 154 void *
 155 xhtml_alloc(char *outopts)
 156 {
 157
 158         return(ml_alloc(outopts, HTML_XHTML_1_0_STRICT));
 159 }
 160
 161
 162 void
 163 html_free(void *p)
 164 {
 165         struct tag      *tag;
 166         struct html     *h;
 167
 168         h = (struct html *)p;
 169
 170         while ((tag = h->tags.head) != NULL) {
 171                 h->tags.head = tag->next;
 172                 free(tag);
 173         }
 174
 175         if (h->symtab)
 176                 mchars_free(h->symtab);
 177
 178         free(h);
 179 }
 180
 181
 182 void
 183 print_gen_head(struct html *h)
 184 {
 185         struct htmlpair  tag[4];
 186
 187         tag[0].key = ATTR_HTTPEQUIV;
 188         tag[0].val = "Content-Type";
 189         tag[1].key = ATTR_CONTENT;
 190         tag[1].val = "text/html; charset=utf-8";
 191         print_otag(h, TAG_META, 2, tag);
 192
 193         tag[0].key = ATTR_NAME;
 194         tag[0].val = "resource-type";
 195         tag[1].key = ATTR_CONTENT;
 196         tag[1].val = "document";
 197         print_otag(h, TAG_META, 2, tag);
 198
 199         if (h->style) {
 200                 tag[0].key = ATTR_REL;
 201                 tag[0].val = "stylesheet";
 202                 tag[1].key = ATTR_HREF;
 203                 tag[1].val = h->style;
 204                 tag[2].key = ATTR_TYPE;
 205                 tag[2].val = "text/css";
 206                 tag[3].key = ATTR_MEDIA;
 207                 tag[3].val = "all";
 208                 print_otag(h, TAG_LINK, 4, tag);
 209         }
 210 }
 211
 212 /* ARGSUSED */
 213 static void
 214 print_num(struct html *h, const char *p, size_t len)
 215 {
 216         char             c;
 217
 218         if ('\0' != (c = mchars_num2char(p, len)))
 219                 putchar((int)c);
 220 }
 221
 222 static void
 223 print_spec(struct html *h, const char *p, size_t len)
 224 {
 225         int              cp;
 226         const char      *rhs;
 227         size_t           sz;
 228
 229         if ((cp = mchars_spec2cp(h->symtab, p, len)) > 0) {
 230                 printf("&#%d;", cp);
 231                 return;
 232         } else if (-1 == cp && 1 == len) {
 233                 fwrite(p, 1, len, stdout);
 234                 return;
 235         } else if (-1 == cp)
 236                 return;
 237
 238         if (NULL != (rhs = mchars_spec2str(h->symtab, p, len, &sz)))
 239                 fwrite(rhs, 1, sz, stdout);
 240 }
 241
 242
 243 static void
 244 print_res(struct html *h, const char *p, size_t len)
 245 {
 246         int              cp;
 247         const char      *rhs;
 248         size_t           sz;
 249
 250         if ((cp = mchars_res2cp(h->symtab, p, len)) > 0) {
 251                 printf("&#%d;", cp);
 252                 return;
 253         } else if (-1 == cp)
 254                 return;
 255
 256         if (NULL != (rhs = mchars_res2str(h->symtab, p, len, &sz)))
 257                 fwrite(rhs, 1, sz, stdout);
 258 }
 259
 260
 261 static void
 262 print_metaf(struct html *h, enum mandoc_esc deco)
 263 {
 264         enum htmlfont    font;
 265
 266         switch (deco) {
 267         case (ESCAPE_FONTPREV):
 268                 font = h->metal;
 269                 break;
 270         case (ESCAPE_FONTITALIC):
 271                 font = HTMLFONT_ITALIC;
 272                 break;
 273         case (ESCAPE_FONTBOLD):
 274                 font = HTMLFONT_BOLD;
 275                 break;
 276         case (ESCAPE_FONTROMAN):
 277                 font = HTMLFONT_NONE;
 278                 break;
 279         default:
 280                 abort();
 281                 /* NOTREACHED */
 282         }
 283
 284         if (h->metaf) {
 285                 print_tagq(h, h->metaf);
 286                 h->metaf = NULL;
 287         }
 288
 289         h->metal = h->metac;
 290         h->metac = font;
 291
 292         if (HTMLFONT_NONE != font)
 293                 h->metaf = HTMLFONT_BOLD == font ?
 294                         print_otag(h, TAG_B, 0, NULL) :
 295                         print_otag(h, TAG_I, 0, NULL);
 296 }
 297
 298 int
 299 html_strlen(const char *cp)
 300 {
 301         int              ssz, sz;
 302         const char      *seq, *p;
 303
 304         /*
 305          * Account for escaped sequences within string length
 306          * calculations.  This follows the logic in term_strlen() as we
 307          * must calculate the width of produced strings.
 308          * Assume that characters are always width of "1".  This is
 309          * hacky, but it gets the job done for approximation of widths.
 310          */
 311
 312         sz = 0;
 313         while (NULL != (p = strchr(cp, '\\'))) {
 314                 sz += (int)(p - cp);
 315                 ++cp;
 316                 switch (mandoc_escape(&cp, &seq, &ssz)) {
 317                 case (ESCAPE_ERROR):
 318                         return(sz);
 319                 case (ESCAPE_NUMBERED):
 320                         /* FALLTHROUGH */
 321                 case (ESCAPE_PREDEF):
 322                         /* FALLTHROUGH */
 323                 case (ESCAPE_SPECIAL):
 324                         sz++;
 325                         break;
 326                 default:
 327                         break;
 328                 }
 329         }
 330
 331         assert(sz >= 0);
 332         return(sz + strlen(cp));
 333 }
 334
 335 static int
 336 print_encode(struct html *h, const char *p, int norecurse)
 337 {
 338         size_t           sz;
 339         int              len, nospace;
 340         const char      *seq;
 341         enum mandoc_esc  esc;
 342         static const char rejs[6] = { '\\', '<', '>', '&', ASCII_HYPH, '\0' };
 343
 344         nospace = 0;
 345
 346         while ('\0' != *p) {
 347                 sz = strcspn(p, rejs);
 348
 349                 fwrite(p, 1, sz, stdout);
 350                 p += (int)sz;
 351
 352                 if ('\0' == *p)
 353                         break;
 354
 355                 switch (*p++) {
 356                 case ('<'):
 357                         printf("&lt;");
 358                         continue;
 359                 case ('>'):
 360                         printf("&gt;");
 361                         continue;
 362                 case ('&'):
 363                         printf("&amp;");
 364                         continue;
 365                 case (ASCII_HYPH):
 366                         putchar('-');
 367                         continue;
 368                 default:
 369                         break;
 370                 }
 371
 372                 esc = mandoc_escape(&p, &seq, &len);
 373                 if (ESCAPE_ERROR == esc)
 374                         break;
 375
 376                 switch (esc) {
 377                 case (ESCAPE_NUMBERED):
 378                         print_num(h, seq, len);
 379                         break;
 380                 case (ESCAPE_PREDEF):
 381                         print_res(h, seq, len);
 382                         break;
 383                 case (ESCAPE_SPECIAL):
 384                         print_spec(h, seq, len);
 385                         break;
 386                 case (ESCAPE_FONTPREV):
 387                         /* FALLTHROUGH */
 388                 case (ESCAPE_FONTBOLD):
 389                         /* FALLTHROUGH */
 390                 case (ESCAPE_FONTITALIC):
 391                         /* FALLTHROUGH */
 392                 case (ESCAPE_FONTROMAN):
 393                         if (norecurse)
 394                                 break;
 395                         print_metaf(h, esc);
 396                         break;
 397                 case (ESCAPE_NOSPACE):
 398                         if ('\0' == *p)
 399                                 nospace = 1;
 400                         break;
 401                 default:
 402                         break;
 403                 }
 404         }
 405
 406         return(nospace);
 407 }
 408
 409
 410 static void
 411 print_attr(struct html *h, const char *key, const char *val)
 412 {
 413         printf(" %s=\"", key);
 414         (void)print_encode(h, val, 1);
 415         putchar('\"');
 416 }
 417
 418
 419 struct tag *
 420 print_otag(struct html *h, enum htmltag tag,
 421                 int sz, const struct htmlpair *p)
 422 {
 423         int              i;
 424         struct tag      *t;
 425
 426         /* Push this tags onto the stack of open scopes. */
 427
 428         if ( ! (HTML_NOSTACK & htmltags[tag].flags)) {
 429                 t = mandoc_malloc(sizeof(struct tag));
 430                 t->tag = tag;
 431                 t->next = h->tags.head;
 432                 h->tags.head = t;
 433         } else
 434                 t = NULL;
 435
 436         if ( ! (HTML_NOSPACE & h->flags))
 437                 if ( ! (HTML_CLRLINE & htmltags[tag].flags)) {
 438                         /* Manage keeps! */
 439                         if ( ! (HTML_KEEP & h->flags)) {
 440                                 if (HTML_PREKEEP & h->flags)
 441                                         h->flags |= HTML_KEEP;
 442                                 putchar(' ');
 443                         } else
 444                                 printf("&#160;");
 445                 }
 446
 447         if ( ! (h->flags & HTML_NONOSPACE))
 448                 h->flags &= ~HTML_NOSPACE;
 449         else
 450                 h->flags |= HTML_NOSPACE;
 451
 452         /* Print out the tag name and attributes. */
 453
 454         printf("<%s", htmltags[tag].name);
 455         for (i = 0; i < sz; i++)
 456                 print_attr(h, htmlattrs[p[i].key], p[i].val);
 457
 458         /* Add non-overridable attributes. */
 459
 460         if (TAG_HTML == tag && HTML_XHTML_1_0_STRICT == h->type) {
 461                 print_attr(h, "xmlns", "http://www.w3.org/1999/xhtml");
 462                 print_attr(h, "xml:lang", "en");
 463                 print_attr(h, "lang", "en");
 464         }
 465
 466         /* Accommodate for XML "well-formed" singleton escaping. */
 467
 468         if (HTML_AUTOCLOSE & htmltags[tag].flags)
 469                 switch (h->type) {
 470                 case (HTML_XHTML_1_0_STRICT):
 471                         putchar('/');
 472                         break;
 473                 default:
 474                         break;
 475                 }
 476
 477         putchar('>');
 478
 479         h->flags |= HTML_NOSPACE;
 480
 481         if ((HTML_AUTOCLOSE | HTML_CLRLINE) & htmltags[tag].flags)
 482                 putchar('\n');
 483
 484         return(t);
 485 }
 486
 487
 488 static void
 489 print_ctag(struct html *h, enum htmltag tag)
 490 {
 491
 492         printf("</%s>", htmltags[tag].name);
 493         if (HTML_CLRLINE & htmltags[tag].flags) {
 494                 h->flags |= HTML_NOSPACE;
 495                 putchar('\n');
 496         }
 497 }
 498
 499
 500 void
 501 print_gen_decls(struct html *h)
 502 {
 503
 504         print_xmltype(h);
 505         print_doctype(h);
 506 }
 507
 508
 509 static void
 510 print_xmltype(struct html *h)
 511 {
 512
 513         if (HTML_XHTML_1_0_STRICT == h->type)
 514                 puts("<?xml version=\"1.0\" encoding=\"UTF-8\"?>");
 515 }
 516
 517
 518 static void
 519 print_doctype(struct html *h)
 520 {
 521         const char      *doctype;
 522         const char      *dtd;
 523         const char      *name;
 524
 525         switch (h->type) {
 526         case (HTML_HTML_4_01_STRICT):
 527                 name = "HTML";
 528                 doctype = "-//W3C//DTD HTML 4.01//EN";
 529                 dtd = "http://www.w3.org/TR/html4/strict.dtd";
 530                 break;
 531         default:
 532                 name = "html";
 533                 doctype = "-//W3C//DTD XHTML 1.0 Strict//EN";
 534                 dtd = "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd";
 535                 break;
 536         }
 537
 538         printf("<!DOCTYPE %s PUBLIC \"%s\" \"%s\">\n",
 539                         name, doctype, dtd);
 540 }
 541
 542 void
 543 print_text(struct html *h, const char *word)
 544 {
 545
 546         if ( ! (HTML_NOSPACE & h->flags)) {
 547                 /* Manage keeps! */
 548                 if ( ! (HTML_KEEP & h->flags)) {
 549                         if (HTML_PREKEEP & h->flags)
 550                                 h->flags |= HTML_KEEP;
 551                         putchar(' ');
 552                 } else
 553                         printf("&#160;");
 554         }
 555
 556         assert(NULL == h->metaf);
 557         if (HTMLFONT_NONE != h->metac)
 558                 h->metaf = HTMLFONT_BOLD == h->metac ?
 559                         print_otag(h, TAG_B, 0, NULL) :
 560                         print_otag(h, TAG_I, 0, NULL);
 561
 562         assert(word);
 563         if ( ! print_encode(h, word, 0))
 564                 if ( ! (h->flags & HTML_NONOSPACE))
 565                         h->flags &= ~HTML_NOSPACE;
 566
 567         if (h->metaf) {
 568                 print_tagq(h, h->metaf);
 569                 h->metaf = NULL;
 570         }
 571
 572         h->flags &= ~HTML_IGNDELIM;
 573 }
 574
 575
 576 void
 577 print_tagq(struct html *h, const struct tag *until)
 578 {
 579         struct tag      *tag;
 580
 581         while ((tag = h->tags.head) != NULL) {
 582                 /*
 583                  * Remember to close out and nullify the current
 584                  * meta-font and table, if applicable.
 585                  */
 586                 if (tag == h->metaf)
 587                         h->metaf = NULL;
 588                 if (tag == h->tblt)
 589                         h->tblt = NULL;
 590                 print_ctag(h, tag->tag);
 591                 h->tags.head = tag->next;
 592                 free(tag);
 593                 if (until && tag == until)
 594                         return;
 595         }
 596 }
 597
 598
 599 void
 600 print_stagq(struct html *h, const struct tag *suntil)
 601 {
 602         struct tag      *tag;
 603
 604         while ((tag = h->tags.head) != NULL) {
 605                 if (suntil && tag == suntil)
 606                         return;
 607                 /*
 608                  * Remember to close out and nullify the current
 609                  * meta-font and table, if applicable.
 610                  */
 611                 if (tag == h->metaf)
 612                         h->metaf = NULL;
 613                 if (tag == h->tblt)
 614                         h->tblt = NULL;
 615                 print_ctag(h, tag->tag);
 616                 h->tags.head = tag->next;
 617                 free(tag);
 618         }
 619 }
 620
 621
 622 void
 623 bufinit(struct html *h)
 624 {
 625
 626         h->buf[0] = '\0';
 627         h->buflen = 0;
 628 }
 629
 630
 631 void
 632 bufcat_style(struct html *h, const char *key, const char *val)
 633 {
 634
 635         bufcat(h, key);
 636         bufncat(h, ":", 1);
 637         bufcat(h, val);
 638         bufncat(h, ";", 1);
 639 }
 640
 641
 642 void
 643 bufcat(struct html *h, const char *p)
 644 {
 645
 646         bufncat(h, p, strlen(p));
 647 }
 648
 649
 650 void
 651 buffmt(struct html *h, const char *fmt, ...)
 652 {
 653         va_list          ap;
 654
 655         va_start(ap, fmt);
 656         (void)vsnprintf(h->buf + (int)h->buflen,
 657                         BUFSIZ - h->buflen - 1, fmt, ap);
 658         va_end(ap);
 659         h->buflen = strlen(h->buf);
 660 }
 661
 662
 663 void
 664 bufncat(struct html *h, const char *p, size_t sz)
 665 {
 666
 667         if (h->buflen + sz > BUFSIZ - 1)
 668                 sz = BUFSIZ - 1 - h->buflen;
 669
 670         (void)strncat(h->buf, p, sz);
 671         h->buflen += sz;
 672 }
 673
 674
 675 void
 676 buffmt_includes(struct html *h, const char *name)
 677 {
 678         const char      *p, *pp;
 679
 680         pp = h->base_includes;
 681
 682         while (NULL != (p = strchr(pp, '%'))) {
 683                 bufncat(h, pp, (size_t)(p - pp));
 684                 switch (*(p + 1)) {
 685                 case('I'):
 686                         bufcat(h, name);
 687                         break;
 688                 default:
 689                         bufncat(h, p, 2);
 690                         break;
 691                 }
 692                 pp = p + 2;
 693         }
 694         if (pp)
 695                 bufcat(h, pp);
 696 }
 697
 698
 699 void
 700 buffmt_man(struct html *h,
 701                 const char *name, const char *sec)
 702 {
 703         const char      *p, *pp;
 704
 705         pp = h->base_man;
 706
 707         /* LINTED */
 708         while (NULL != (p = strchr(pp, '%'))) {
 709                 bufncat(h, pp, (size_t)(p - pp));
 710                 switch (*(p + 1)) {
 711                 case('S'):
 712                         bufcat(h, sec ? sec : "1");
 713                         break;
 714                 case('N'):
 715                         buffmt(h, name);
 716                         break;
 717                 default:
 718                         bufncat(h, p, 2);
 719                         break;
 720                 }
 721                 pp = p + 2;
 722         }
 723         if (pp)
 724                 bufcat(h, pp);
 725 }
 726
 727
 728 void
 729 bufcat_su(struct html *h, const char *p, const struct roffsu *su)
 730 {
 731         double           v;
 732         const char      *u;
 733
 734         v = su->scale;
 735
 736         switch (su->unit) {
 737         case (SCALE_CM):
 738                 u = "cm";
 739                 break;
 740         case (SCALE_IN):
 741                 u = "in";
 742                 break;
 743         case (SCALE_PC):
 744                 u = "pc";
 745                 break;
 746         case (SCALE_PT):
 747                 u = "pt";
 748                 break;
 749         case (SCALE_EM):
 750                 u = "em";
 751                 break;
 752         case (SCALE_MM):
 753                 if (0 == (v /= 100))
 754                         v = 1;
 755                 u = "em";
 756                 break;
 757         case (SCALE_EN):
 758                 u = "ex";
 759                 break;
 760         case (SCALE_BU):
 761                 u = "ex";
 762                 break;
 763         case (SCALE_VS):
 764                 u = "em";
 765                 break;
 766         default:
 767                 u = "ex";
 768                 break;
 769         }
 770
 771         /*
 772          * XXX: the CSS spec isn't clear as to which types accept
 773          * integer or real numbers, so we just make them all decimals.
 774          */
 775         buffmt(h, "%s: %.2f%s;", p, v, u);
 776 }
 777
 778
 779 void
 780 html_idcat(char *dst, const char *src, int sz)
 781 {
 782         int              ssz;
 783
 784         assert(sz > 2);
 785
 786         /* Cf. <http://www.w3.org/TR/html4/types.html#h-6.2>. */
 787
 788         /* We can't start with a number (bah). */
 789
 790         if ('#' == *dst) {
 791                 dst++;
 792                 sz--;
 793         }
 794         if ('\0' == *dst) {
 795                 *dst++ = 'x';
 796                 *dst = '\0';
 797                 sz--;
 798         }
 799
 800         for ( ; *dst != '\0' && sz; dst++, sz--)
 801                 /* Jump to end. */ ;
 802
 803         for ( ; *src != '\0' && sz > 1; src++) {
 804                 ssz = snprintf(dst, (size_t)sz, "%.2x", *src);
 805                 sz -= ssz;
 806                 dst += ssz;
 807         }
 808 }