html.c

   1 /*      $Id: html.c,v 1.137 2011/04/30 22:24:31 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 "out.h"
  35 #include "html.h"
  36 #include "main.h"
  37
  38 struct  htmldata {
  39         const char       *name;
  40         int               flags;
  41 #define HTML_CLRLINE     (1 << 0)
  42 #define HTML_NOSTACK     (1 << 1)
  43 #define HTML_AUTOCLOSE   (1 << 2) /* Tag has auto-closure. */
  44 };
  45
  46 static  const struct htmldata htmltags[TAG_MAX] = {
  47         {"html",        HTML_CLRLINE}, /* TAG_HTML */
  48         {"head",        HTML_CLRLINE}, /* TAG_HEAD */
  49         {"body",        HTML_CLRLINE}, /* TAG_BODY */
  50         {"meta",        HTML_CLRLINE | HTML_NOSTACK | HTML_AUTOCLOSE}, /* TAG_META */
  51         {"title",       HTML_CLRLINE}, /* TAG_TITLE */
  52         {"div",         HTML_CLRLINE}, /* TAG_DIV */
  53         {"h1",          0}, /* TAG_H1 */
  54         {"h2",          0}, /* TAG_H2 */
  55         {"span",        0}, /* TAG_SPAN */
  56         {"link",        HTML_CLRLINE | HTML_NOSTACK | HTML_AUTOCLOSE}, /* TAG_LINK */
  57         {"br",          HTML_CLRLINE | HTML_NOSTACK | HTML_AUTOCLOSE}, /* TAG_BR */
  58         {"a",           0}, /* TAG_A */
  59         {"table",       HTML_CLRLINE}, /* TAG_TABLE */
  60         {"tbody",       HTML_CLRLINE}, /* TAG_TBODY */
  61         {"col",         HTML_CLRLINE | HTML_NOSTACK | HTML_AUTOCLOSE}, /* TAG_COL */
  62         {"tr",          HTML_CLRLINE}, /* TAG_TR */
  63         {"td",          HTML_CLRLINE}, /* TAG_TD */
  64         {"li",          HTML_CLRLINE}, /* TAG_LI */
  65         {"ul",          HTML_CLRLINE}, /* TAG_UL */
  66         {"ol",          HTML_CLRLINE}, /* TAG_OL */
  67         {"dl",          HTML_CLRLINE}, /* TAG_DL */
  68         {"dt",          HTML_CLRLINE}, /* TAG_DT */
  69         {"dd",          HTML_CLRLINE}, /* TAG_DD */
  70         {"blockquote",  HTML_CLRLINE}, /* TAG_BLOCKQUOTE */
  71         {"p",           HTML_CLRLINE | HTML_NOSTACK | HTML_AUTOCLOSE}, /* TAG_P */
  72         {"pre",         HTML_CLRLINE }, /* TAG_PRE */
  73         {"b",           0 }, /* TAG_B */
  74         {"i",           0 }, /* TAG_I */
  75         {"code",        0 }, /* TAG_CODE */
  76         {"small",       0 }, /* TAG_SMALL */
  77 };
  78
  79 static  const char      *const htmlattrs[ATTR_MAX] = {
  80         "http-equiv", /* ATTR_HTTPEQUIV */
  81         "content", /* ATTR_CONTENT */
  82         "name", /* ATTR_NAME */
  83         "rel", /* ATTR_REL */
  84         "href", /* ATTR_HREF */
  85         "type", /* ATTR_TYPE */
  86         "media", /* ATTR_MEDIA */
  87         "class", /* ATTR_CLASS */
  88         "style", /* ATTR_STYLE */
  89         "width", /* ATTR_WIDTH */
  90         "id", /* ATTR_ID */
  91         "summary", /* ATTR_SUMMARY */
  92         "align", /* ATTR_ALIGN */
  93         "colspan", /* ATTR_COLSPAN */
  94 };
  95
  96 static  void              print_num(struct html *, const char *, size_t);
  97 static  void              print_spec(struct html *, const char *, size_t);
  98 static  void              print_res(struct html *, const char *, size_t);
  99 static  void              print_ctag(struct html *, enum htmltag);
 100 static  void              print_doctype(struct html *);
 101 static  void              print_xmltype(struct html *);
 102 static  int               print_encode(struct html *, const char *, int);
 103 static  void              print_metaf(struct html *, enum mandoc_esc);
 104 static  void              print_attr(struct html *,
 105                                 const char *, const char *);
 106 static  void             *ml_alloc(char *, enum htmltype);
 107
 108
 109 static void *
 110 ml_alloc(char *outopts, enum htmltype type)
 111 {
 112         struct html     *h;
 113         const char      *toks[4];
 114         char            *v;
 115
 116         toks[0] = "style";
 117         toks[1] = "man";
 118         toks[2] = "includes";
 119         toks[3] = NULL;
 120
 121         h = mandoc_calloc(1, sizeof(struct html));
 122
 123         h->type = type;
 124         h->tags.head = NULL;
 125         h->symtab = mchars_alloc();
 126
 127         while (outopts && *outopts)
 128                 switch (getsubopt(&outopts, UNCONST(toks), &v)) {
 129                 case (0):
 130                         h->style = v;
 131                         break;
 132                 case (1):
 133                         h->base_man = v;
 134                         break;
 135                 case (2):
 136                         h->base_includes = v;
 137                         break;
 138                 default:
 139                         break;
 140                 }
 141
 142         return(h);
 143 }
 144
 145 void *
 146 html_alloc(char *outopts)
 147 {
 148
 149         return(ml_alloc(outopts, HTML_HTML_4_01_STRICT));
 150 }
 151
 152
 153 void *
 154 xhtml_alloc(char *outopts)
 155 {
 156
 157         return(ml_alloc(outopts, HTML_XHTML_1_0_STRICT));
 158 }
 159
 160
 161 void
 162 html_free(void *p)
 163 {
 164         struct tag      *tag;
 165         struct html     *h;
 166
 167         h = (struct html *)p;
 168
 169         while ((tag = h->tags.head) != NULL) {
 170                 h->tags.head = tag->next;
 171                 free(tag);
 172         }
 173
 174         if (h->symtab)
 175                 mchars_free(h->symtab);
 176
 177         free(h);
 178 }
 179
 180
 181 void
 182 print_gen_head(struct html *h)
 183 {
 184         struct htmlpair  tag[4];
 185
 186         tag[0].key = ATTR_HTTPEQUIV;
 187         tag[0].val = "Content-Type";
 188         tag[1].key = ATTR_CONTENT;
 189         tag[1].val = "text/html; charset=utf-8";
 190         print_otag(h, TAG_META, 2, tag);
 191
 192         tag[0].key = ATTR_NAME;
 193         tag[0].val = "resource-type";
 194         tag[1].key = ATTR_CONTENT;
 195         tag[1].val = "document";
 196         print_otag(h, TAG_META, 2, tag);
 197
 198         if (h->style) {
 199                 tag[0].key = ATTR_REL;
 200                 tag[0].val = "stylesheet";
 201                 tag[1].key = ATTR_HREF;
 202                 tag[1].val = h->style;
 203                 tag[2].key = ATTR_TYPE;
 204                 tag[2].val = "text/css";
 205                 tag[3].key = ATTR_MEDIA;
 206                 tag[3].val = "all";
 207                 print_otag(h, TAG_LINK, 4, tag);
 208         }
 209 }
 210
 211 /* ARGSUSED */
 212 static void
 213 print_num(struct html *h, const char *p, size_t len)
 214 {
 215         char             c;
 216
 217         if ('\0' != (c = mchars_num2char(p, len)))
 218                 putchar((int)c);
 219 }
 220
 221 static void
 222 print_spec(struct html *h, const char *p, size_t len)
 223 {
 224         int              cp;
 225         const char      *rhs;
 226         size_t           sz;
 227
 228         if ((cp = mchars_spec2cp(h->symtab, p, len)) > 0) {
 229                 printf("&#%d;", cp);
 230                 return;
 231         } else if (-1 == cp && 1 == len) {
 232                 fwrite(p, 1, len, stdout);
 233                 return;
 234         } else if (-1 == cp)
 235                 return;
 236
 237         if (NULL != (rhs = mchars_spec2str(h->symtab, p, len, &sz)))
 238                 fwrite(rhs, 1, sz, stdout);
 239 }
 240
 241
 242 static void
 243 print_res(struct html *h, const char *p, size_t len)
 244 {
 245         int              cp;
 246         const char      *rhs;
 247         size_t           sz;
 248
 249         if ((cp = mchars_res2cp(h->symtab, p, len)) > 0) {
 250                 printf("&#%d;", cp);
 251                 return;
 252         } else if (-1 == cp)
 253                 return;
 254
 255         if (NULL != (rhs = mchars_res2str(h->symtab, p, len, &sz)))
 256                 fwrite(rhs, 1, sz, stdout);
 257 }
 258
 259
 260 static void
 261 print_metaf(struct html *h, enum mandoc_esc deco)
 262 {
 263         enum htmlfont    font;
 264
 265         switch (deco) {
 266         case (ESCAPE_FONTPREV):
 267                 font = h->metal;
 268                 break;
 269         case (ESCAPE_FONTITALIC):
 270                 font = HTMLFONT_ITALIC;
 271                 break;
 272         case (ESCAPE_FONTBOLD):
 273                 font = HTMLFONT_BOLD;
 274                 break;
 275         case (ESCAPE_FONTROMAN):
 276                 font = HTMLFONT_NONE;
 277                 break;
 278         default:
 279                 abort();
 280                 /* NOTREACHED */
 281         }
 282
 283         if (h->metaf) {
 284                 print_tagq(h, h->metaf);
 285                 h->metaf = NULL;
 286         }
 287
 288         h->metal = h->metac;
 289         h->metac = font;
 290
 291         if (HTMLFONT_NONE != font)
 292                 h->metaf = HTMLFONT_BOLD == font ?
 293                         print_otag(h, TAG_B, 0, NULL) :
 294                         print_otag(h, TAG_I, 0, NULL);
 295 }
 296
 297
 298 static int
 299 print_encode(struct html *h, const char *p, int norecurse)
 300 {
 301         size_t           sz;
 302         int              len, nospace;
 303         const char      *seq;
 304         enum mandoc_esc  esc;
 305         static const char rejs[6] = { '\\', '<', '>', '&', ASCII_HYPH, '\0' };
 306
 307         nospace = 0;
 308
 309         while ('\0' != *p) {
 310                 sz = strcspn(p, rejs);
 311
 312                 fwrite(p, 1, sz, stdout);
 313                 p += (int)sz;
 314
 315                 if ('\0' == *p)
 316                         break;
 317
 318                 switch (*p++) {
 319                 case ('<'):
 320                         printf("&lt;");
 321                         continue;
 322                 case ('>'):
 323                         printf("&gt;");
 324                         continue;
 325                 case ('&'):
 326                         printf("&amp;");
 327                         continue;
 328                 case (ASCII_HYPH):
 329                         putchar('-');
 330                         continue;
 331                 default:
 332                         break;
 333                 }
 334
 335                 esc = mandoc_escape(&p, &seq, &len);
 336                 if (ESCAPE_ERROR == esc)
 337                         break;
 338
 339                 switch (esc) {
 340                 case (ESCAPE_NUMBERED):
 341                         print_num(h, seq, len);
 342                         break;
 343                 case (ESCAPE_PREDEF):
 344                         print_res(h, seq, len);
 345                         break;
 346                 case (ESCAPE_SPECIAL):
 347                         print_spec(h, seq, len);
 348                         break;
 349                 case (ESCAPE_FONTPREV):
 350                         /* FALLTHROUGH */
 351                 case (ESCAPE_FONTBOLD):
 352                         /* FALLTHROUGH */
 353                 case (ESCAPE_FONTITALIC):
 354                         /* FALLTHROUGH */
 355                 case (ESCAPE_FONTROMAN):
 356                         if (norecurse)
 357                                 break;
 358                         print_metaf(h, esc);
 359                         break;
 360                 case (ESCAPE_NOSPACE):
 361                         if ('\0' == *p)
 362                                 nospace = 1;
 363                         break;
 364                 default:
 365                         break;
 366                 }
 367         }
 368
 369         return(nospace);
 370 }
 371
 372
 373 static void
 374 print_attr(struct html *h, const char *key, const char *val)
 375 {
 376         printf(" %s=\"", key);
 377         (void)print_encode(h, val, 1);
 378         putchar('\"');
 379 }
 380
 381
 382 struct tag *
 383 print_otag(struct html *h, enum htmltag tag,
 384                 int sz, const struct htmlpair *p)
 385 {
 386         int              i;
 387         struct tag      *t;
 388
 389         /* Push this tags onto the stack of open scopes. */
 390
 391         if ( ! (HTML_NOSTACK & htmltags[tag].flags)) {
 392                 t = mandoc_malloc(sizeof(struct tag));
 393                 t->tag = tag;
 394                 t->next = h->tags.head;
 395                 h->tags.head = t;
 396         } else
 397                 t = NULL;
 398
 399         if ( ! (HTML_NOSPACE & h->flags))
 400                 if ( ! (HTML_CLRLINE & htmltags[tag].flags)) {
 401                         /* Manage keeps! */
 402                         if ( ! (HTML_KEEP & h->flags)) {
 403                                 if (HTML_PREKEEP & h->flags)
 404                                         h->flags |= HTML_KEEP;
 405                                 putchar(' ');
 406                         } else
 407                                 printf("&#160;");
 408                 }
 409
 410         if ( ! (h->flags & HTML_NONOSPACE))
 411                 h->flags &= ~HTML_NOSPACE;
 412         else
 413                 h->flags |= HTML_NOSPACE;
 414
 415         /* Print out the tag name and attributes. */
 416
 417         printf("<%s", htmltags[tag].name);
 418         for (i = 0; i < sz; i++)
 419                 print_attr(h, htmlattrs[p[i].key], p[i].val);
 420
 421         /* Add non-overridable attributes. */
 422
 423         if (TAG_HTML == tag && HTML_XHTML_1_0_STRICT == h->type) {
 424                 print_attr(h, "xmlns", "http://www.w3.org/1999/xhtml");
 425                 print_attr(h, "xml:lang", "en");
 426                 print_attr(h, "lang", "en");
 427         }
 428
 429         /* Accommodate for XML "well-formed" singleton escaping. */
 430
 431         if (HTML_AUTOCLOSE & htmltags[tag].flags)
 432                 switch (h->type) {
 433                 case (HTML_XHTML_1_0_STRICT):
 434                         putchar('/');
 435                         break;
 436                 default:
 437                         break;
 438                 }
 439
 440         putchar('>');
 441
 442         h->flags |= HTML_NOSPACE;
 443
 444         if ((HTML_AUTOCLOSE | HTML_CLRLINE) & htmltags[tag].flags)
 445                 putchar('\n');
 446
 447         return(t);
 448 }
 449
 450
 451 static void
 452 print_ctag(struct html *h, enum htmltag tag)
 453 {
 454
 455         printf("</%s>", htmltags[tag].name);
 456         if (HTML_CLRLINE & htmltags[tag].flags) {
 457                 h->flags |= HTML_NOSPACE;
 458                 putchar('\n');
 459         }
 460 }
 461
 462
 463 void
 464 print_gen_decls(struct html *h)
 465 {
 466
 467         print_xmltype(h);
 468         print_doctype(h);
 469 }
 470
 471
 472 static void
 473 print_xmltype(struct html *h)
 474 {
 475
 476         if (HTML_XHTML_1_0_STRICT == h->type)
 477                 puts("<?xml version=\"1.0\" encoding=\"UTF-8\"?>");
 478 }
 479
 480
 481 static void
 482 print_doctype(struct html *h)
 483 {
 484         const char      *doctype;
 485         const char      *dtd;
 486         const char      *name;
 487
 488         switch (h->type) {
 489         case (HTML_HTML_4_01_STRICT):
 490                 name = "HTML";
 491                 doctype = "-//W3C//DTD HTML 4.01//EN";
 492                 dtd = "http://www.w3.org/TR/html4/strict.dtd";
 493                 break;
 494         default:
 495                 name = "html";
 496                 doctype = "-//W3C//DTD XHTML 1.0 Strict//EN";
 497                 dtd = "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd";
 498                 break;
 499         }
 500
 501         printf("<!DOCTYPE %s PUBLIC \"%s\" \"%s\">\n",
 502                         name, doctype, dtd);
 503 }
 504
 505 void
 506 print_text(struct html *h, const char *word)
 507 {
 508
 509         if ( ! (HTML_NOSPACE & h->flags)) {
 510                 /* Manage keeps! */
 511                 if ( ! (HTML_KEEP & h->flags)) {
 512                         if (HTML_PREKEEP & h->flags)
 513                                 h->flags |= HTML_KEEP;
 514                         putchar(' ');
 515                 } else
 516                         printf("&#160;");
 517         }
 518
 519         assert(NULL == h->metaf);
 520         if (HTMLFONT_NONE != h->metac)
 521                 h->metaf = HTMLFONT_BOLD == h->metac ?
 522                         print_otag(h, TAG_B, 0, NULL) :
 523                         print_otag(h, TAG_I, 0, NULL);
 524
 525         assert(word);
 526         if ( ! print_encode(h, word, 0))
 527                 if ( ! (h->flags & HTML_NONOSPACE))
 528                         h->flags &= ~HTML_NOSPACE;
 529
 530         if (h->metaf) {
 531                 print_tagq(h, h->metaf);
 532                 h->metaf = NULL;
 533         }
 534
 535         h->flags &= ~HTML_IGNDELIM;
 536 }
 537
 538
 539 void
 540 print_tagq(struct html *h, const struct tag *until)
 541 {
 542         struct tag      *tag;
 543
 544         while ((tag = h->tags.head) != NULL) {
 545                 /*
 546                  * Remember to close out and nullify the current
 547                  * meta-font and table, if applicable.
 548                  */
 549                 if (tag == h->metaf)
 550                         h->metaf = NULL;
 551                 if (tag == h->tblt)
 552                         h->tblt = NULL;
 553                 print_ctag(h, tag->tag);
 554                 h->tags.head = tag->next;
 555                 free(tag);
 556                 if (until && tag == until)
 557                         return;
 558         }
 559 }
 560
 561
 562 void
 563 print_stagq(struct html *h, const struct tag *suntil)
 564 {
 565         struct tag      *tag;
 566
 567         while ((tag = h->tags.head) != NULL) {
 568                 if (suntil && tag == suntil)
 569                         return;
 570                 /*
 571                  * Remember to close out and nullify the current
 572                  * meta-font and table, if applicable.
 573                  */
 574                 if (tag == h->metaf)
 575                         h->metaf = NULL;
 576                 if (tag == h->tblt)
 577                         h->tblt = NULL;
 578                 print_ctag(h, tag->tag);
 579                 h->tags.head = tag->next;
 580                 free(tag);
 581         }
 582 }
 583
 584
 585 void
 586 bufinit(struct html *h)
 587 {
 588
 589         h->buf[0] = '\0';
 590         h->buflen = 0;
 591 }
 592
 593
 594 void
 595 bufcat_style(struct html *h, const char *key, const char *val)
 596 {
 597
 598         bufcat(h, key);
 599         bufncat(h, ":", 1);
 600         bufcat(h, val);
 601         bufncat(h, ";", 1);
 602 }
 603
 604
 605 void
 606 bufcat(struct html *h, const char *p)
 607 {
 608
 609         bufncat(h, p, strlen(p));
 610 }
 611
 612
 613 void
 614 buffmt(struct html *h, const char *fmt, ...)
 615 {
 616         va_list          ap;
 617
 618         va_start(ap, fmt);
 619         (void)vsnprintf(h->buf + (int)h->buflen,
 620                         BUFSIZ - h->buflen - 1, fmt, ap);
 621         va_end(ap);
 622         h->buflen = strlen(h->buf);
 623 }
 624
 625
 626 void
 627 bufncat(struct html *h, const char *p, size_t sz)
 628 {
 629
 630         if (h->buflen + sz > BUFSIZ - 1)
 631                 sz = BUFSIZ - 1 - h->buflen;
 632
 633         (void)strncat(h->buf, p, sz);
 634         h->buflen += sz;
 635 }
 636
 637
 638 void
 639 buffmt_includes(struct html *h, const char *name)
 640 {
 641         const char      *p, *pp;
 642
 643         pp = h->base_includes;
 644
 645         while (NULL != (p = strchr(pp, '%'))) {
 646                 bufncat(h, pp, (size_t)(p - pp));
 647                 switch (*(p + 1)) {
 648                 case('I'):
 649                         bufcat(h, name);
 650                         break;
 651                 default:
 652                         bufncat(h, p, 2);
 653                         break;
 654                 }
 655                 pp = p + 2;
 656         }
 657         if (pp)
 658                 bufcat(h, pp);
 659 }
 660
 661
 662 void
 663 buffmt_man(struct html *h,
 664                 const char *name, const char *sec)
 665 {
 666         const char      *p, *pp;
 667
 668         pp = h->base_man;
 669
 670         /* LINTED */
 671         while (NULL != (p = strchr(pp, '%'))) {
 672                 bufncat(h, pp, (size_t)(p - pp));
 673                 switch (*(p + 1)) {
 674                 case('S'):
 675                         bufcat(h, sec ? sec : "1");
 676                         break;
 677                 case('N'):
 678                         buffmt(h, name);
 679                         break;
 680                 default:
 681                         bufncat(h, p, 2);
 682                         break;
 683                 }
 684                 pp = p + 2;
 685         }
 686         if (pp)
 687                 bufcat(h, pp);
 688 }
 689
 690
 691 void
 692 bufcat_su(struct html *h, const char *p, const struct roffsu *su)
 693 {
 694         double           v;
 695         const char      *u;
 696
 697         v = su->scale;
 698
 699         switch (su->unit) {
 700         case (SCALE_CM):
 701                 u = "cm";
 702                 break;
 703         case (SCALE_IN):
 704                 u = "in";
 705                 break;
 706         case (SCALE_PC):
 707                 u = "pc";
 708                 break;
 709         case (SCALE_PT):
 710                 u = "pt";
 711                 break;
 712         case (SCALE_EM):
 713                 u = "em";
 714                 break;
 715         case (SCALE_MM):
 716                 if (0 == (v /= 100))
 717                         v = 1;
 718                 u = "em";
 719                 break;
 720         case (SCALE_EN):
 721                 u = "ex";
 722                 break;
 723         case (SCALE_BU):
 724                 u = "ex";
 725                 break;
 726         case (SCALE_VS):
 727                 u = "em";
 728                 break;
 729         default:
 730                 u = "ex";
 731                 break;
 732         }
 733
 734         /*
 735          * XXX: the CSS spec isn't clear as to which types accept
 736          * integer or real numbers, so we just make them all decimals.
 737          */
 738         buffmt(h, "%s: %.2f%s;", p, v, u);
 739 }
 740
 741
 742 void
 743 html_idcat(char *dst, const char *src, int sz)
 744 {
 745         int              ssz;
 746
 747         assert(sz > 2);
 748
 749         /* Cf. <http://www.w3.org/TR/html4/types.html#h-6.2>. */
 750
 751         /* We can't start with a number (bah). */
 752
 753         if ('#' == *dst) {
 754                 dst++;
 755                 sz--;
 756         }
 757         if ('\0' == *dst) {
 758                 *dst++ = 'x';
 759                 *dst = '\0';
 760                 sz--;
 761         }
 762
 763         for ( ; *dst != '\0' && sz; dst++, sz--)
 764                 /* Jump to end. */ ;
 765
 766         for ( ; *src != '\0' && sz > 1; src++) {
 767                 ssz = snprintf(dst, (size_t)sz, "%.2x", *src);
 768                 sz -= ssz;
 769                 dst += ssz;
 770         }
 771 }