mdw@git.distorted.org.uk Git - sgt/halibut/blob - bk_pdf.c

   1 /*
   2  * PDF backend for Halibut
   3  */
   4
   5 #include <assert.h>
   6 #include "halibut.h"
   7 #include "paper.h"
   8
   9 #define TREE_BRANCH 2                  /* max branching factor in page tree */
  10
  11 paragraph *pdf_config_filename(char *filename)
  12 {
  13     return cmdline_cfg_simple("pdf-filename", filename, NULL);
  14 }
  15
  16 typedef struct object_Tag object;
  17 typedef struct objlist_Tag objlist;
  18
  19 struct object_Tag {
  20     objlist *list;
  21     object *next;
  22     int number;
  23     rdstringc main, stream;
  24     int size, fileoff;
  25     char *final;
  26 };
  27
  28 struct objlist_Tag {
  29     int number;
  30     object *head, *tail;
  31 };
  32
  33 static object *new_object(objlist *list);
  34 static void objtext(object *o, char const *text);
  35 static void objstream(object *o, char const *text);
  36 static void pdf_string(void (*add)(object *, char const *),
  37                        object *, char const *);
  38 static void pdf_string_len(void (*add)(object *, char const *),
  39                            object *, char const *, int);
  40 static void objref(object *o, object *dest);
  41 static char *pdf_outline_convert(wchar_t *s, int *len);
  42
  43 static int is_std_font(char const *name);
  44
  45 static void make_pages_node(object *node, object *parent, page_data *first,
  46                             page_data *last, object *resources,
  47                             object *mediabox);
  48 static int make_outline(object *parent, outline_element *start, int n,
  49                         int open);
  50 static int pdf_versionid(FILE *fp, word *words);
  51
  52 void pdf_backend(paragraph *sourceform, keywordlist *keywords,
  53                  indexdata *idx, void *vdoc) {
  54     document *doc = (document *)vdoc;
  55     int font_index;
  56     font_encoding *fe;
  57     page_data *page;
  58     int pageno;
  59     FILE *fp;
  60     char *filename;
  61     paragraph *p;
  62     objlist olist;
  63     object *o, *info, *cat, *outlines, *pages, *resources, *mediabox;
  64     int fileoff;
  65
  66     IGNORE(keywords);
  67     IGNORE(idx);
  68
  69     filename = dupstr("output.pdf");
  70     for (p = sourceform; p; p = p->next) {
  71         if (p->type == para_Config) {
  72             if (!ustricmp(p->keyword, L"pdf-filename")) {
  73                 sfree(filename);
  74                 filename = dupstr(adv(p->origkeyword));
  75             }
  76         }
  77     }
  78
  79     olist.head = olist.tail = NULL;
  80     olist.number = 1;
  81
  82     {
  83         char buf[256];
  84
  85         info = new_object(&olist);
  86         objtext(info, "<<\n");
  87         if (doc->n_outline_elements > 0) {
  88             char *title;
  89             int titlelen;
  90
  91             title =
  92                pdf_outline_convert(doc->outline_elements->pdata->outline_title,
  93                                         &titlelen);
  94             objtext(info, "/Title ");
  95             pdf_string_len(objtext, info, title, titlelen);
  96             sfree(title);
  97             objtext(info, "\n");
  98         }
  99         objtext(info, "/Producer ");
 100         sprintf(buf, "Halibut, %s", version);
 101         pdf_string(objtext, info, buf);
 102         objtext(info, "\n>>\n");
 103     }
 104
 105     cat = new_object(&olist);
 106     if (doc->n_outline_elements > 0)
 107         outlines = new_object(&olist);
 108     else
 109         outlines = NULL;
 110     pages = new_object(&olist);
 111     resources = new_object(&olist);
 112
 113     /*
 114      * The catalogue just contains references to the outlines and
 115      * pages objects.
 116      */
 117     objtext(cat, "<<\n/Type /Catalog");
 118     if (outlines) {
 119         objtext(cat, "\n/Outlines ");
 120         objref(cat, outlines);
 121     }
 122     objtext(cat, "\n/Pages ");
 123     objref(cat, pages);
 124     if (outlines)
 125         objtext(cat, "\n/PageMode /UseOutlines");
 126     objtext(cat, "\n>>\n");
 127
 128     /*
 129      * Set up the resources dictionary, which mostly means
 130      * providing all the font objects and names to call them by.
 131      */
 132     font_index = 0;
 133     objtext(resources, "<<\n/Font <<\n");
 134     for (fe = doc->fonts->head; fe; fe = fe->next) {
 135         char fname[40];
 136         int i;
 137         object *font;
 138
 139         sprintf(fname, "f%d", font_index++);
 140         fe->name = dupstr(fname);
 141
 142         font = new_object(&olist);
 143
 144         objtext(resources, "/");
 145         objtext(resources, fe->name);
 146         objtext(resources, " ");
 147         objref(resources, font);
 148         objtext(resources, "\n");
 149
 150         objtext(font, "<<\n/Type /Font\n/Subtype /Type1\n/Name /");
 151         objtext(font, fe->name);
 152         objtext(font, "\n/BaseFont /");
 153         objtext(font, fe->font->info->name);
 154         objtext(font, "\n/Encoding <<\n/Type /Encoding\n/Differences [");
 155
 156         for (i = 0; i < 256; i++) {
 157             char buf[20];
 158             if (!fe->vector[i])
 159                 continue;
 160             sprintf(buf, "\n%d /", i);
 161             objtext(font, buf);
 162             objtext(font, fe->vector[i] ? fe->vector[i] : ".notdef");
 163         }
 164
 165         objtext(font, "\n]\n>>\n");
 166
 167 #define FF_FIXEDPITCH   0x00000001
 168 #define FF_SERIF        0x00000002
 169 #define FF_SYMBOLIC     0x00000004
 170 #define FF_SCRIPT       0x00000008
 171 #define FF_NONSYMBOLIC  0x00000020
 172 #define FF_ITALIC       0x00000040
 173 #define FF_ALLCAP       0x00010000
 174 #define FF_SMALLCAP     0x00020000
 175 #define FF_FORCEBOLD    0x00040000
 176
 177         if (!is_std_font(fe->font->info->name)){
 178             object *widths = new_object(&olist);
 179             object *fontdesc = new_object(&olist);
 180             int firstchar = -1, lastchar = -1;
 181             char buf[80];
 182             font_info const *fi = fe->font->info;
 183             int flags;
 184             for (i = 0; i < 256; i++)
 185                 if (fe->indices[i] >= 0) {
 186                     if (firstchar < 0) firstchar = i;
 187                     lastchar = i;
 188                 }
 189             sprintf(buf, "/FirstChar %d\n/LastChar %d\n/Widths ",
 190                     firstchar, lastchar);
 191             objtext(font, buf);
 192             objref(font, widths);
 193             objtext(font, "\n");
 194             objtext(widths, "[\n");
 195             for (i = firstchar; i <= lastchar; i++) {
 196                 double width;
 197                 if (fe->indices[i] < 0)
 198                     width = 0.0;
 199                 else
 200                     width = fi->widths[fe->indices[i]];
 201                 sprintf(buf, "%g\n", 1000.0 * width / FUNITS_PER_PT);
 202                 objtext(widths, buf);
 203             }
 204             objtext(widths, "]\n");
 205             objtext(font, "/FontDescriptor ");
 206             objref(font, fontdesc);
 207             objtext(fontdesc, "<<\n/Type /FontDescriptor\n/Name /");
 208             objtext(fontdesc, fi->name);
 209             flags = 0;
 210             if (fi->italicangle) flags |= FF_ITALIC;
 211             flags |= FF_NONSYMBOLIC;
 212             sprintf(buf, "\n/Flags %d\n", flags);
 213             objtext(fontdesc, buf);
 214             sprintf(buf, "/FontBBox [%g %g %g %g]\n", fi->fontbbox[0],
 215                     fi->fontbbox[1], fi->fontbbox[2], fi->fontbbox[3]);
 216             objtext(fontdesc, buf);
 217             sprintf(buf, "/ItalicAngle %g\n", fi->italicangle);
 218             objtext(fontdesc, buf);
 219             sprintf(buf, "/Ascent %g\n", fi->ascent);
 220             objtext(fontdesc, buf);
 221             sprintf(buf, "/Descent %g\n", fi->descent);
 222             objtext(fontdesc, buf);
 223             sprintf(buf, "/CapHeight %g\n", fi->capheight);
 224             objtext(fontdesc, buf);
 225             sprintf(buf, "/XHeight %g\n", fi->xheight);
 226             objtext(fontdesc, buf);
 227             sprintf(buf, "/StemH %g\n", fi->stemh);
 228             objtext(fontdesc, buf);
 229             sprintf(buf, "/StemV %g\n", fi->stemv);
 230             objtext(fontdesc, buf);
 231             if (fi->fp) {
 232                 object *fontfile = new_object(&olist);
 233                 char buf[513];
 234                 size_t len;
 235                 rewind(fi->fp);
 236                 do {
 237                     len = fread(buf, 1, sizeof(buf)-1, fi->fp);
 238                     buf[len] = 0;
 239                     objstream(fontfile, buf);
 240                 } while (len == sizeof(buf)-1);
 241                 objtext(fontdesc, "/FontFile ");
 242                 objref(fontdesc, fontfile);
 243             }
 244             objtext(fontdesc, "\n>>\n");
 245         }
 246
 247         objtext(font, "\n>>\n");
 248     }
 249     objtext(resources, ">>\n>>\n");
 250
 251     {
 252         char buf[255];
 253         mediabox = new_object(&olist);
 254         sprintf(buf, "[0 0 %g %g]\n",
 255                 doc->paper_width / FUNITS_PER_PT,
 256                 doc->paper_height / FUNITS_PER_PT);
 257         objtext(mediabox, buf);
 258     }
 259
 260     /*
 261      * Define the page objects for each page, and get each one
 262      * ready to have a `Parent' specification added to it.
 263      */
 264     for (page = doc->pages; page; page = page->next) {
 265         object *opage;
 266
 267         opage = new_object(&olist);
 268         page->spare = opage;
 269         objtext(opage, "<<\n/Type /Page\n");
 270     }
 271
 272     /*
 273      * Recursively build the page tree.
 274      */
 275     make_pages_node(pages, NULL, doc->pages, NULL, resources, mediabox);
 276
 277     /*
 278      * Create and render the individual pages.
 279      */
 280     pageno = 0;
 281     for (page = doc->pages; page; page = page->next) {
 282         object *opage, *cstr;
 283         rect *r;
 284         text_fragment *frag, *frag_end;
 285         char buf[256];
 286         int x, y, lx, ly;
 287
 288         opage = (object *)page->spare;
 289         /*
 290          * At this point the page dictionary is already
 291          * half-written, with /Type and /Parent already present. We
 292          * continue from there.
 293          */
 294
 295         /*
 296          * The PDF spec says /Resources is required, but also says
 297          * that it's inheritable and may be omitted if it's present
 298          * in a Pages node. In our case it is: it's present in the
 299          * topmost /Pages node because we carefully put it there.
 300          * So we don't need a /Resources entry here.  The same applies
 301          * to /MediaBox.
 302          */
 303
 304         /*
 305          * Now we're ready to define a content stream containing
 306          * the actual text on the page.
 307          */
 308         cstr = new_object(&olist);
 309         objtext(opage, "/Contents ");
 310         objref(opage, cstr);
 311         objtext(opage, "\n");
 312
 313         /*
 314          * Render any rectangles on the page.
 315          */
 316         for (r = page->first_rect; r; r = r->next) {
 317             char buf[512];
 318             sprintf(buf, "%g %g %g %g re f\n",
 319                     r->x / FUNITS_PER_PT, r->y / FUNITS_PER_PT,
 320                     r->w / FUNITS_PER_PT, r->h / FUNITS_PER_PT);
 321             objstream(cstr, buf);
 322         }
 323
 324         objstream(cstr, "BT\n");
 325
 326         /*
 327          * PDF tracks two separate current positions: the position
 328          * given in the `line matrix' and the position given in the
 329          * `text matrix'. We must therefore track both as well.
 330          * They start off at -1 (unset).
 331          */
 332         lx = ly = -1;
 333         x = y = -1;
 334
 335         frag = page->first_text;
 336         while (frag) {
 337             /*
 338              * For compactness, I'm going to group text fragments
 339              * into subsequences that use the same font+size. So
 340              * first find the end of this subsequence.
 341              */
 342             for (frag_end = frag;
 343                  (frag_end &&
 344                   frag_end->fe == frag->fe &&
 345                   frag_end->fontsize == frag->fontsize);
 346                  frag_end = frag_end->next);
 347
 348             /*
 349              * Now select the text fragment, and prepare to display
 350              * the text.
 351              */
 352             objstream(cstr, "/");
 353             objstream(cstr, frag->fe->name);
 354             sprintf(buf, " %d Tf ", frag->fontsize);
 355             objstream(cstr, buf);
 356
 357             while (frag && frag != frag_end) {
 358                 /*
 359                  * Place the text position for the first piece of
 360                  * text.
 361                  */
 362                 if (lx < 0) {
 363                     sprintf(buf, "1 0 0 1 %g %g Tm ",
 364                             frag->x/FUNITS_PER_PT, frag->y/FUNITS_PER_PT);
 365                 } else {
 366                     sprintf(buf, "%g %g Td ",
 367                             (frag->x - lx)/FUNITS_PER_PT,
 368                             (frag->y - ly)/FUNITS_PER_PT);
 369                 }
 370                 objstream(cstr, buf);
 371                 lx = x = frag->x;
 372                 ly = y = frag->y;
 373
 374                 /*
 375                  * See if we're going to use Tj (show a single
 376                  * string) or TJ (show an array of strings with
 377                  * x-spacings between them). We determine this by
 378                  * seeing if there's more than one text fragment in
 379                  * sequence with the same y-coordinate.
 380                  */
 381                 if (frag->next && frag->next != frag_end &&
 382                     frag->next->y == y) {
 383                     /*
 384                      * The TJ strategy.
 385                      */
 386                     objstream(cstr, "[");
 387                     while (frag && frag != frag_end && frag->y == y) {
 388                         if (frag->x != x) {
 389                             sprintf(buf, "%g",
 390                                     (x - frag->x) * 1000.0 /
 391                                     (FUNITS_PER_PT * frag->fontsize));
 392                             objstream(cstr, buf);
 393                         }
 394                         pdf_string(objstream, cstr, frag->text);
 395                         x = frag->x + frag->width;
 396                         frag = frag->next;
 397                     }
 398                     objstream(cstr, "]TJ\n");
 399                 } else
 400                 {
 401                     /*
 402                      * The Tj strategy.
 403                      */
 404                     pdf_string(objstream, cstr, frag->text);
 405                     objstream(cstr, "Tj\n");
 406                     frag = frag->next;
 407                 }
 408             }
 409         }
 410         objstream(cstr, "ET");
 411
 412         /*
 413          * Also, we want an annotation dictionary containing the
 414          * cross-references from this page.
 415          */
 416         if (page->first_xref) {
 417             xref *xr;
 418             objtext(opage, "/Annots [\n");
 419
 420             for (xr = page->first_xref; xr; xr = xr->next) {
 421                 object *annot;
 422                 char buf[256];
 423
 424                 annot = new_object(&olist);
 425                 objref(opage, annot);
 426                 objtext(opage, "\n");
 427
 428                 objtext(annot, "<<\n/Type /Annot\n/Subtype /Link\n/Rect [");
 429                 sprintf(buf, "%g %g %g %g",
 430                         xr->lx / FUNITS_PER_PT, xr->by / FUNITS_PER_PT,
 431                         xr->rx / FUNITS_PER_PT, xr->ty / FUNITS_PER_PT);
 432                 objtext(annot, buf);
 433                 objtext(annot, "]\n/Border [0 0 0]\n");
 434
 435                 if (xr->dest.type == PAGE) {
 436                     objtext(annot, "/Dest [");
 437                     objref(annot, (object *)xr->dest.page->spare);
 438                     objtext(annot, " /XYZ null null null]\n");
 439                 } else {
 440                     objtext(annot, "/A <<\n/Type /Action\n/S /URI\n/URI ");
 441                     pdf_string(objtext, annot, xr->dest.url);
 442                     objtext(annot, "\n>>\n");
 443                 }
 444
 445                 objtext(annot, ">>\n");
 446             }
 447
 448             objtext(opage, "]\n");
 449         }
 450
 451         objtext(opage, ">>\n");
 452     }
 453
 454     /*
 455      * Set up the outlines dictionary.
 456      */
 457     if (outlines) {
 458         int topcount;
 459         char buf[80];
 460
 461         objtext(outlines, "<<\n/Type /Outlines\n");
 462         topcount = make_outline(outlines, doc->outline_elements,
 463                                 doc->n_outline_elements, TRUE);
 464         sprintf(buf, "/Count %d\n>>\n", topcount);
 465         objtext(outlines, buf);
 466     }
 467
 468     /*
 469      * Assemble the final linear form of every object.
 470      */
 471     for (o = olist.head; o; o = o->next) {
 472         rdstringc rs = {0, 0, NULL};
 473         char text[80];
 474
 475         sprintf(text, "%d 0 obj\n", o->number);
 476         rdaddsc(&rs, text);
 477
 478         if (!o->main.text && o->stream.text) {
 479             sprintf(text, "<<\n/Length %d\n>>\n", o->stream.pos);
 480             rdaddsc(&o->main, text);
 481         }
 482
 483         assert(o->main.text);
 484         rdaddsc(&rs, o->main.text);
 485         sfree(o->main.text);
 486
 487         if (rs.text[rs.pos-1] != '\n')
 488             rdaddc(&rs, '\n');
 489
 490         if (o->stream.text) {
 491             /*
 492              * FIXME: If we ever start compressing stream data then
 493              * it will have zero bytes in it, so we'll have to be
 494              * more careful than this.
 495              */
 496             rdaddsc(&rs, "stream\n");
 497             rdaddsc(&rs, o->stream.text);
 498             rdaddsc(&rs, "\nendstream\n");
 499             sfree(o->stream.text);
 500         }
 501
 502         rdaddsc(&rs, "endobj\n");
 503
 504         o->final = rs.text;
 505         o->size = rs.pos;
 506     }
 507
 508     /*
 509      * Write out the PDF file.
 510      */
 511
 512     fp = fopen(filename, "wb");
 513     if (!fp) {
 514         error(err_cantopenw, filename);
 515         return;
 516     }
 517
 518     /*
 519      * Header. I'm going to put the version IDs in the header as
 520      * well, simply in PDF comments.
 521      */
 522     fileoff = fprintf(fp, "%%PDF-1.3\n");
 523     for (p = sourceform; p; p = p->next)
 524         if (p->type == para_VersionID)
 525             fileoff += pdf_versionid(fp, p->words);
 526
 527     /*
 528      * Body
 529      */
 530     for (o = olist.head; o; o = o->next) {
 531         o->fileoff = fileoff;
 532         fwrite(o->final, 1, o->size, fp);
 533         fileoff += o->size;
 534     }
 535
 536     /*
 537      * Cross-reference table
 538      */
 539     fprintf(fp, "xref\n");
 540     assert(olist.head->number == 1);
 541     fprintf(fp, "0 %d\n", olist.tail->number + 1);
 542     fprintf(fp, "0000000000 65535 f \n");
 543     for (o = olist.head; o; o = o->next) {
 544         char entry[40];
 545         sprintf(entry, "%010d 00000 n \n", o->fileoff);
 546         assert(strlen(entry) == 20);
 547         fputs(entry, fp);
 548     }
 549
 550     /*
 551      * Trailer
 552      */
 553     fprintf(fp, "trailer\n<<\n/Size %d\n/Root %d 0 R\n/Info %d 0 R\n>>\n",
 554             olist.tail->number + 1, cat->number, info->number);
 555     fprintf(fp, "startxref\n%d\n%%%%EOF\n", fileoff);
 556
 557     fclose(fp);
 558
 559     sfree(filename);
 560 }
 561
 562 static object *new_object(objlist *list)
 563 {
 564     object *obj = snew(object);
 565
 566     obj->list = list;
 567
 568     obj->main.text = NULL;
 569     obj->main.pos = obj->main.size = 0;
 570     obj->stream.text = NULL;
 571     obj->stream.pos = obj->stream.size = 0;
 572
 573     obj->number = list->number++;
 574
 575     obj->next = NULL;
 576     if (list->tail)
 577         list->tail->next = obj;
 578     else
 579         list->head = obj;
 580     list->tail = obj;
 581
 582     obj->size = 0;
 583     obj->final = NULL;
 584
 585     return obj;
 586 }
 587
 588 static void objtext(object *o, char const *text)
 589 {
 590     rdaddsc(&o->main, text);
 591 }
 592
 593 static void objstream(object *o, char const *text)
 594 {
 595     rdaddsc(&o->stream, text);
 596 }
 597
 598 static void objref(object *o, object *dest)
 599 {
 600     char buf[40];
 601     sprintf(buf, "%d 0 R", dest->number);
 602     rdaddsc(&o->main, buf);
 603 }
 604
 605 static char const * const stdfonts[] = {
 606     "Times-Roman", "Times-Bold", "Times-Italic", "Times-BoldItalic",
 607     "Helvetica", "Helvetica-Bold", "Helvetica-Oblique","Helvetica-BoldOblique",
 608     "Courier", "Courier-Bold", "Courier-Oblique", "Courier-BoldOblique",
 609     "Symbol", "ZapfDingbats"
 610 };
 611
 612 static int is_std_font(char const *name) {
 613     unsigned i;
 614     for (i = 0; i < lenof(stdfonts); i++)
 615         if (strcmp(name, stdfonts[i]) == 0)
 616             return TRUE;
 617     return FALSE;
 618 }
 619
 620 static void make_pages_node(object *node, object *parent, page_data *first,
 621                             page_data *last, object *resources,
 622                             object *mediabox)
 623 {
 624     int count;
 625     page_data *page;
 626     char buf[80];
 627
 628     objtext(node, "<<\n/Type /Pages\n");
 629     if (parent) {
 630         objtext(node, "/Parent ");
 631         objref(node, parent);
 632         objtext(node, "\n");
 633     }
 634
 635     /*
 636      * Count the pages in this stretch, to see if there are few
 637      * enough to reference directly.
 638      */
 639     count = 0;
 640     for (page = first; page; page = page->next) {
 641         count++;
 642         if (page == last)
 643             break;
 644     }
 645
 646     sprintf(buf, "/Count %d\n/Kids [\n", count);
 647     objtext(node, buf);
 648
 649     if (count > TREE_BRANCH) {
 650         int i;
 651         page_data *thisfirst, *thislast;
 652
 653         page = first;
 654
 655         for (i = 0; i < TREE_BRANCH; i++) {
 656             int number = (i+1) * count / TREE_BRANCH - i * count / TREE_BRANCH;
 657             thisfirst = page;
 658             while (number--) {
 659                 thislast = page;
 660                 page = page->next;
 661             }
 662
 663             if (thisfirst == thislast) {
 664                 objref(node, (object *)thisfirst->spare);
 665                 objtext((object *)thisfirst->spare, "/Parent ");
 666                 objref((object *)thisfirst->spare, node);
 667                 objtext((object *)thisfirst->spare, "\n");
 668             } else {
 669                 object *newnode = new_object(node->list);
 670                 make_pages_node(newnode, node, thisfirst, thislast,
 671                                 NULL, NULL);
 672                 objref(node, newnode);
 673             }
 674             objtext(node, "\n");
 675         }
 676
 677         assert(thislast == last || page == NULL);
 678
 679     } else {
 680         for (page = first; page; page = page->next) {
 681             objref(node, (object *)page->spare);
 682             objtext(node, "\n");
 683             objtext((object *)page->spare, "/Parent ");
 684             objref((object *)page->spare, node);
 685             objtext((object *)page->spare, "\n");
 686             if (page == last)
 687                 break;
 688         }
 689     }
 690
 691     objtext(node, "]\n");
 692
 693     if (resources) {
 694         objtext(node, "/Resources ");
 695         objref(node, resources);
 696         objtext(node, "\n");
 697     }
 698     if (mediabox) {
 699         objtext(node, "/MediaBox ");
 700         objref(node, mediabox);
 701         objtext(node, "\n");
 702     }
 703
 704     objtext(node, ">>\n");
 705 }
 706
 707 /*
 708  * In text on the page, PDF uses the PostScript font model, which
 709  * means that glyphs are identified by PS strings and hence font
 710  * encoding can be managed independently of the supplied encoding
 711  * of the font. However, in the document outline, the PDF spec
 712  * encodes in either PDFDocEncoding (a custom superset of
 713  * ISO-8859-1) or UTF-16BE.
 714  */
 715 static char *pdf_outline_convert(wchar_t *s, int *len) {
 716     char *ret;
 717
 718     ret = utoa_careful_dup(s, CS_PDF);
 719
 720     /*
 721      * Very silly special case: if the returned string begins with
 722      * FE FF, then the PDF reader will mistake it for a UTF-16BE
 723      * string. So in this case we give up on PDFDocEncoding and
 724      * encode it in UTF-16 straight away.
 725      */
 726     if (ret && ret[0] == '\xFE' && ret[1] == '\xFF') {
 727         sfree(ret);
 728         ret = NULL;
 729     }
 730
 731     if (!ret) {
 732         ret = utoa_dup_len(s, CS_UTF16BE, len);
 733     } else {
 734         *len = strlen(ret);
 735     }
 736
 737     return ret;
 738 }
 739
 740 static int make_outline(object *parent, outline_element *items, int n,
 741                         int open)
 742 {
 743     int level, totalcount = 0;
 744     outline_element *itemp;
 745     object *curr, *prev = NULL, *first = NULL, *last = NULL;
 746
 747     assert(n > 0);
 748
 749     level = items->level;
 750
 751     while (n > 0) {
 752         char *title;
 753         int titlelen;
 754
 755         /*
 756          * Here we expect to be sitting on an item at the given
 757          * level. So we start by constructing an outline entry for
 758          * that item.
 759          */
 760         assert(items->level == level);
 761
 762         title = pdf_outline_convert(items->pdata->outline_title, &titlelen);
 763
 764         totalcount++;
 765         curr = new_object(parent->list);
 766         if (!first) first = curr;
 767         last = curr;
 768         objtext(curr, "<<\n/Title ");
 769         pdf_string_len(objtext, curr, title, titlelen);
 770         sfree(title);
 771         objtext(curr, "\n/Parent ");
 772         objref(curr, parent);
 773         objtext(curr, "\n/Dest [");
 774         objref(curr, (object *)items->pdata->first->page->spare);
 775         objtext(curr, " /XYZ null null null]\n");
 776         if (prev) {
 777             objtext(curr, "/Prev ");
 778             objref(curr, prev);
 779             objtext(curr, "\n");
 780
 781             objtext(prev, "/Next ");
 782             objref(prev, curr);
 783             objtext(prev, "\n>>\n");
 784         }
 785         prev = curr;
 786
 787         items++, n--;
 788         for (itemp = items; itemp < items+n && itemp->level > level;
 789              itemp++);
 790
 791         if (itemp > items) {
 792             char buf[80];
 793             int count = make_outline(curr, items, itemp - items, FALSE);
 794             if (!open)
 795                 count = -count;
 796             else
 797                 totalcount += count;
 798             sprintf(buf, "/Count %d\n", count);
 799             objtext(curr, buf);
 800         }
 801
 802         n -= itemp - items;
 803         items = itemp;
 804     }
 805     objtext(prev, ">>\n");
 806
 807     assert(first && last);
 808     objtext(parent, "/First ");
 809     objref(parent, first);
 810     objtext(parent, "\n/Last ");
 811     objref(parent, last);
 812     objtext(parent, "\n");
 813
 814     return totalcount;
 815 }
 816
 817 static int pdf_versionid(FILE *fp, word *words)
 818 {
 819     int ret;
 820
 821     ret = fprintf(fp, "%% ");
 822
 823     for (; words; words = words->next) {
 824         char *text;
 825         int type;
 826
 827         switch (words->type) {
 828           case word_HyperLink:
 829           case word_HyperEnd:
 830           case word_UpperXref:
 831           case word_LowerXref:
 832           case word_XrefEnd:
 833           case word_IndexRef:
 834             continue;
 835         }
 836
 837         type = removeattr(words->type);
 838
 839         switch (type) {
 840           case word_Normal:
 841             text = utoa_dup(words->text, CS_ASCII);
 842             break;
 843           case word_WhiteSpace:
 844             text = dupstr(" ");
 845             break;
 846           case word_Quote:
 847             text = dupstr("'");
 848             break;
 849         }
 850
 851         fputs(text, fp);
 852         ret += strlen(text);
 853         sfree(text);
 854     }
 855
 856     ret += fprintf(fp, "\n");
 857
 858     return ret;
 859 }
 860
 861 static void pdf_string_len(void (*add)(object *, char const *),
 862                            object *o, char const *str, int len)
 863 {
 864     char const *p;
 865
 866     add(o, "(");
 867     for (p = str; len > 0; p++, len--) {
 868         char c[10];
 869         if (*p < ' ' || *p > '~') {
 870             sprintf(c, "\\%03o", 0xFF & (int)*p);
 871         } else {
 872             int n = 0;
 873             if (*p == '\\' || *p == '(' || *p == ')')
 874                 c[n++] = '\\';
 875             c[n++] = *p;
 876             c[n] = '\0';
 877         }
 878         add(o, c);
 879     }
 880     add(o, ")");
 881 }
 882
 883 static void pdf_string(void (*add)(object *, char const *),
 884                        object *o, char const *str)
 885 {
 886     pdf_string_len(add, o, str, strlen(str));
 887 }