lib/tagpos.c

   1 /* tagpos.c */
   2
   3 /*
   4  * Copyright (C) 2011-2022 by Werner Lemberg.
   5  *
   6  * This file is part of the ttfautohint library, and may only be used,
   7  * modified, and distributed under the terms given in `COPYING'.  By
   8  * continuing to use, modify, or distribute this file you indicate that you
   9  * have read `COPYING' and understand and accept it fully.
  10  *
  11  * The file `COPYING' mentioned in the previous paragraph is distributed
  12  * with the ttfautohint library.
  13  */
  14
  15
  16 #include "ta.h"
  17
  18
  19 /* the code below contains many redundancies; */
  20 /* it has been written for clarity */
  21
  22 #define VALUE(val, p) val = NEXT_USHORT(p)
  23 #define OFFSET(val, base, p) val = base + NEXT_USHORT(p)
  24
  25
  26 /* this simple `Coverage_table' structure wastes memory... */
  27
  28 typedef struct Coverage_table_
  29 {
  30   FT_UShort num_glyph_idxs;
  31   FT_UShort* glyph_idxs;
  32 } Coverage_table;
  33
  34
  35 static FT_Error
  36 TA_read_coverage_table(FT_Byte* p,
  37                        Coverage_table* cov,
  38                        SFNT* sfnt,
  39                        FONT* font)
  40 {
  41   SFNT_Table* GPOS_table = &font->tables[sfnt->GPOS_idx];
  42
  43   FT_UShort* glyph_idxs;
  44
  45   FT_UShort CoverageFormat;
  46   FT_UShort i;
  47
  48
  49   cov->num_glyph_idxs = 0;
  50   cov->glyph_idxs = NULL;
  51
  52   VALUE(CoverageFormat, p);
  53
  54   if (CoverageFormat == 1)
  55   {
  56     FT_UShort GlyphCount;
  57
  58
  59     VALUE(GlyphCount, p);
  60
  61     /* rough sanity checks */
  62     if (GlyphCount * 2 > GPOS_table->len)
  63       return FT_Err_Invalid_Table;
  64     if (p - GPOS_table->buf > (ptrdiff_t)(GPOS_table->len - GlyphCount * 2))
  65       return FT_Err_Invalid_Table;
  66
  67     glyph_idxs = (FT_UShort*)malloc(GlyphCount * sizeof (FT_UShort));
  68     if (!glyph_idxs)
  69       return FT_Err_Out_Of_Memory;
  70
  71     /* loop over p */
  72     for (i = 0; i < GlyphCount; i++)
  73     {
  74       FT_UShort idx;
  75
  76
  77       VALUE(idx, p);
  78       glyph_idxs[i] = idx;
  79     }
  80
  81     cov->num_glyph_idxs = GlyphCount;
  82   }
  83
  84   else if (CoverageFormat == 2)
  85   {
  86     FT_UShort RangeCount;
  87     FT_UShort start;
  88     FT_UShort end;
  89     FT_UShort count;
  90     FT_Byte* p_start;
  91
  92
  93     VALUE(RangeCount, p);
  94
  95     /* rough sanity checks */
  96     if (RangeCount * 6 > GPOS_table->len)
  97       return FT_Err_Invalid_Table;
  98     if (p - GPOS_table->buf > (ptrdiff_t)(GPOS_table->len - RangeCount * 6))
  99       return FT_Err_Invalid_Table;
 100
 101     p_start = p;
 102     count = 0;
 103
 104     /* loop over p */
 105     for (i = 0; i < RangeCount; i++)
 106     {
 107       /* collect number of glyphs */
 108       VALUE(start, p);
 109       VALUE(end, p);
 110
 111       if (end < start)
 112         return FT_Err_Invalid_Table;
 113
 114       p += 2; /* skip StartCoverageIndex */
 115       count += end - start + 1;
 116     }
 117
 118     glyph_idxs = (FT_UShort*)malloc(count * sizeof (FT_UShort));
 119     if (!glyph_idxs)
 120       return FT_Err_Out_Of_Memory;
 121
 122     p = p_start;
 123     count = 0;
 124
 125     /* loop again over p */
 126     for (i = 0; i < RangeCount; i++)
 127     {
 128       FT_UShort j;
 129
 130
 131       VALUE(start, p);
 132       VALUE(end, p);
 133       p += 2; /* skip StartCoverageIndex */
 134
 135       for (j = start; j <= end; j++)
 136         glyph_idxs[count++] = j;
 137     }
 138
 139     cov->num_glyph_idxs = count;
 140   }
 141   else
 142     return FT_Err_Invalid_Table;
 143
 144   cov->glyph_idxs = glyph_idxs;
 145
 146   return TA_Err_Ok;
 147 }
 148
 149
 150 /* We add a subglyph for each composite glyph. */
 151 /* Since subglyphs must contain at least one point, */
 152 /* we have to adjust all AnchorPoints in GPOS AnchorTables accordingly. */
 153 /* Using the `pointsums' array of the `GLYPH' structure */
 154 /* it is straightforward to do that: */
 155 /* Assuming that anchor point x is in the interval */
 156 /* pointsums[n] <= x < pointsums[n + 1], */
 157 /* the new point index is x + n. */
 158
 159 static FT_Error
 160 TA_update_anchor(FT_Byte* p,
 161                  FT_UShort glyph_idx,
 162                  SFNT* sfnt,
 163                  FONT* font)
 164 {
 165   SFNT_Table* GPOS_table = &font->tables[sfnt->GPOS_idx];
 166   SFNT_Table* glyf_table = &font->tables[sfnt->glyf_idx];
 167   glyf_Data* data = (glyf_Data*)glyf_table->data;
 168   GLYPH* glyph = &data->glyphs[glyph_idx];
 169
 170   FT_UShort AnchorFormat;
 171
 172
 173   /* nothing to do for simple glyphs */
 174   if (!glyph->num_components)
 175     return TA_Err_Ok;
 176
 177   VALUE(AnchorFormat, p);
 178
 179   if (AnchorFormat == 2)
 180   {
 181     FT_UShort AnchorPoint;
 182     FT_UShort i;
 183
 184
 185     p += 4; /* skip XCoordinate and YCoordinate */
 186     VALUE(AnchorPoint, p);
 187
 188     /* sanity check */
 189     if (p > GPOS_table->buf + GPOS_table->len)
 190       return FT_Err_Invalid_Table;
 191
 192     /* search point offset */
 193     for (i = 0; i < glyph->num_pointsums; i++)
 194       if (AnchorPoint < glyph->pointsums[i])
 195         break;
 196
 197     *(p - 2) = HIGH(AnchorPoint + i);
 198     *(p - 1) = LOW(AnchorPoint + i);
 199   }
 200
 201   return TA_Err_Ok;
 202 }
 203
 204
 205 static FT_Error
 206 TA_handle_cursive_lookup(FT_Byte* Lookup,
 207                          FT_Byte* p,
 208                          SFNT* sfnt,
 209                          FONT* font)
 210 {
 211   FT_UShort SubTableCount;
 212   Coverage_table cov;
 213   FT_Error error;
 214
 215
 216   p += 2; /* skip LookupFlag */
 217   VALUE(SubTableCount, p);
 218
 219   /* loop over p */
 220   for (; SubTableCount > 0; SubTableCount--)
 221   {
 222     FT_Byte* CursivePosFormat1;
 223     FT_Byte* Coverage;
 224     FT_UShort EntryExitCount;
 225
 226     FT_Byte* q;
 227     FT_UShort i;
 228
 229
 230     OFFSET(CursivePosFormat1, Lookup, p);
 231
 232     q = CursivePosFormat1;
 233     q += 2; /* skip PosFormat */
 234     OFFSET(Coverage, CursivePosFormat1, q);
 235     VALUE(EntryExitCount, q);
 236
 237     error = TA_read_coverage_table(Coverage, &cov, sfnt, font);
 238     if (error)
 239       return error;
 240
 241     /* sanity check */
 242     if (cov.num_glyph_idxs != EntryExitCount)
 243     {
 244       error = FT_Err_Invalid_Table;
 245       goto Fail;
 246     }
 247
 248     /* loop over q */
 249     for (i = 0; i < EntryExitCount; i++)
 250     {
 251       FT_UShort glyph_idx = cov.glyph_idxs[i];
 252       FT_Byte* EntryAnchor;
 253       FT_Byte* ExitAnchor;
 254
 255
 256       OFFSET(EntryAnchor, CursivePosFormat1, q);
 257       error = TA_update_anchor(EntryAnchor, glyph_idx, sfnt, font);
 258       if (error)
 259         goto Fail;
 260
 261       OFFSET(ExitAnchor, CursivePosFormat1, q);
 262       error = TA_update_anchor(ExitAnchor, glyph_idx, sfnt, font);
 263       if (error)
 264         goto Fail;
 265     }
 266
 267     free(cov.glyph_idxs);
 268     cov.glyph_idxs = NULL;
 269   }
 270
 271   return TA_Err_Ok;
 272
 273 Fail:
 274   free(cov.glyph_idxs);
 275   return error;
 276 }
 277
 278
 279 static FT_Error
 280 TA_handle_markbase_lookup(FT_Byte* Lookup,
 281                           FT_Byte* p,
 282                           SFNT* sfnt,
 283                           FONT* font)
 284 {
 285   FT_UShort SubTableCount;
 286   Coverage_table cov;
 287   FT_Error error;
 288
 289
 290   p += 2; /* skip LookupFlag */
 291   VALUE(SubTableCount, p);
 292
 293   /* loop over p */
 294   for (; SubTableCount > 0; SubTableCount--)
 295   {
 296     FT_Byte* MarkBasePosFormat1;
 297     FT_Byte* MarkCoverage;
 298     FT_Byte* BaseCoverage;
 299     FT_UShort ClassCount;
 300     FT_UShort MarkCount;
 301     FT_Byte* MarkArray;
 302     FT_UShort BaseCount;
 303     FT_Byte* BaseArray;
 304
 305     FT_Byte* q;
 306     FT_UShort i;
 307
 308
 309     OFFSET(MarkBasePosFormat1, Lookup, p);
 310
 311     q = MarkBasePosFormat1;
 312     q += 2; /* skip PosFormat */
 313     OFFSET(MarkCoverage, MarkBasePosFormat1, q);
 314     OFFSET(BaseCoverage, MarkBasePosFormat1, q);
 315     VALUE(ClassCount, q);
 316     OFFSET(MarkArray, MarkBasePosFormat1, q);
 317     OFFSET(BaseArray, MarkBasePosFormat1, q);
 318
 319     error = TA_read_coverage_table(MarkCoverage, &cov, sfnt, font);
 320     if (error)
 321       return error;
 322
 323     q = MarkArray;
 324     VALUE(MarkCount, q);
 325
 326     /* sanity check */
 327     if (cov.num_glyph_idxs != MarkCount)
 328     {
 329       error = FT_Err_Invalid_Table;
 330       goto Fail;
 331     }
 332
 333     /* loop over q */
 334     for (i = 0; i < MarkCount; i++)
 335     {
 336       FT_UShort glyph_idx = cov.glyph_idxs[i];
 337       FT_Byte* MarkAnchor;
 338
 339
 340       q += 2; /* skip Class */
 341       OFFSET(MarkAnchor, MarkArray, q);
 342       error = TA_update_anchor(MarkAnchor, glyph_idx, sfnt, font);
 343       if (error)
 344         return error;
 345     }
 346
 347     free(cov.glyph_idxs);
 348
 349     error = TA_read_coverage_table(BaseCoverage, &cov, sfnt, font);
 350     if (error)
 351       return error;
 352
 353     q = BaseArray;
 354     VALUE(BaseCount, q);
 355
 356     /* sanity check */
 357     if (cov.num_glyph_idxs != BaseCount)
 358     {
 359       error = FT_Err_Invalid_Table;
 360       goto Fail;
 361     }
 362
 363     /* loop over q */
 364     for (i = 0; i < BaseCount; i++)
 365     {
 366       FT_UShort glyph_idx = cov.glyph_idxs[i];
 367       FT_UShort cc = ClassCount;
 368
 369
 370       for (; cc > 0; cc--)
 371       {
 372         FT_Byte* BaseAnchor;
 373
 374
 375         OFFSET(BaseAnchor, BaseArray, q);
 376         error = TA_update_anchor(BaseAnchor, glyph_idx, sfnt, font);
 377         if (error)
 378           return error;
 379       }
 380     }
 381
 382     free(cov.glyph_idxs);
 383     cov.glyph_idxs = NULL;
 384   }
 385
 386   return TA_Err_Ok;
 387
 388 Fail:
 389   free(cov.glyph_idxs);
 390   return error;
 391 }
 392
 393
 394 static FT_Error
 395 TA_handle_marklig_lookup(FT_Byte* Lookup,
 396                          FT_Byte* p,
 397                          SFNT* sfnt,
 398                          FONT* font)
 399 {
 400   FT_UShort SubTableCount;
 401   Coverage_table cov;
 402   FT_Error error;
 403
 404
 405   p += 2; /* skip LookupFlag */
 406   VALUE(SubTableCount, p);
 407
 408   /* loop over p */
 409   for (; SubTableCount > 0; SubTableCount--)
 410   {
 411     FT_Byte* MarkLigPosFormat1;
 412     FT_Byte* MarkCoverage;
 413     FT_Byte* LigatureCoverage;
 414     FT_UShort ClassCount;
 415     FT_UShort MarkCount;
 416     FT_Byte* MarkArray;
 417     FT_UShort LigatureCount;
 418     FT_Byte* LigatureArray;
 419
 420     FT_Byte* q;
 421     FT_UShort i;
 422
 423
 424     OFFSET(MarkLigPosFormat1, Lookup, p);
 425
 426     q = MarkLigPosFormat1;
 427     q += 2; /* skip PosFormat */
 428     OFFSET(MarkCoverage, MarkLigPosFormat1, q);
 429     OFFSET(LigatureCoverage, MarkLigPosFormat1, q);
 430     VALUE(ClassCount, q);
 431     OFFSET(MarkArray, MarkLigPosFormat1, q);
 432     OFFSET(LigatureArray, MarkLigPosFormat1, q);
 433
 434     error = TA_read_coverage_table(MarkCoverage, &cov, sfnt, font);
 435     if (error)
 436       return error;
 437
 438     q = MarkArray;
 439     VALUE(MarkCount, q);
 440
 441     /* sanity check */
 442     if (cov.num_glyph_idxs != MarkCount)
 443     {
 444       error = FT_Err_Invalid_Table;
 445       goto Fail;
 446     }
 447
 448     /* loop over q */
 449     for (i = 0; i < MarkCount; i++)
 450     {
 451       FT_UShort glyph_idx = cov.glyph_idxs[i];
 452       FT_Byte* MarkAnchor;
 453
 454
 455       q += 2; /* skip Class */
 456       OFFSET(MarkAnchor, MarkArray, q);
 457       error = TA_update_anchor(MarkAnchor, glyph_idx, sfnt, font);
 458       if (error)
 459         return error;
 460     }
 461
 462     free(cov.glyph_idxs);
 463
 464     error = TA_read_coverage_table(LigatureCoverage, &cov, sfnt, font);
 465     if (error)
 466       return error;
 467
 468     q = LigatureArray;
 469     VALUE(LigatureCount, q);
 470
 471     /* sanity check */
 472     if (cov.num_glyph_idxs != LigatureCount)
 473     {
 474       error = FT_Err_Invalid_Table;
 475       goto Fail;
 476     }
 477
 478     /* loop over q */
 479     for (i = 0; i < LigatureCount; i++)
 480     {
 481       FT_UShort glyph_idx = cov.glyph_idxs[i];
 482       FT_Byte* LigatureAttach;
 483       FT_UShort ComponentCount;
 484       FT_Byte* r;
 485
 486
 487       OFFSET(LigatureAttach, LigatureArray, q);
 488
 489       r = LigatureAttach;
 490       VALUE(ComponentCount, r);
 491
 492       /* loop over r */
 493       for (; ComponentCount > 0; ComponentCount--)
 494       {
 495         FT_UShort cc = ClassCount;
 496
 497
 498         for (; cc > 0; cc--)
 499         {
 500           FT_Byte* LigatureAnchor;
 501
 502
 503           OFFSET(LigatureAnchor, LigatureAttach, r);
 504           error = TA_update_anchor(LigatureAnchor, glyph_idx, sfnt, font);
 505           if (error)
 506             return error;
 507         }
 508       }
 509     }
 510
 511     free(cov.glyph_idxs);
 512     cov.glyph_idxs = NULL;
 513   }
 514
 515   return TA_Err_Ok;
 516
 517 Fail:
 518   free(cov.glyph_idxs);
 519   return error;
 520 }
 521
 522
 523 static FT_Error
 524 TA_handle_markmark_lookup(FT_Byte* Lookup,
 525                           FT_Byte* p,
 526                           SFNT* sfnt,
 527                           FONT* font)
 528 {
 529   FT_UShort SubTableCount;
 530   Coverage_table cov;
 531   FT_Error error;
 532
 533
 534   p += 2; /* skip LookupFlag */
 535   VALUE(SubTableCount, p);
 536
 537   /* loop over p */
 538   for (; SubTableCount > 0; SubTableCount--)
 539   {
 540     FT_Byte* MarkMarkPosFormat1;
 541     FT_Byte* Mark1Coverage;
 542     FT_Byte* Mark2Coverage;
 543     FT_UShort ClassCount;
 544     FT_UShort Mark1Count;
 545     FT_Byte* Mark1Array;
 546     FT_UShort Mark2Count;
 547     FT_Byte* Mark2Array;
 548
 549     FT_Byte* q;
 550     FT_UShort i;
 551
 552
 553     OFFSET(MarkMarkPosFormat1, Lookup, p);
 554
 555     q = MarkMarkPosFormat1;
 556     q += 2; /* skip PosFormat */
 557     OFFSET(Mark1Coverage, MarkMarkPosFormat1, q);
 558     OFFSET(Mark2Coverage, MarkMarkPosFormat1, q);
 559     VALUE(ClassCount, q);
 560     OFFSET(Mark1Array, MarkMarkPosFormat1, q);
 561     OFFSET(Mark2Array, MarkMarkPosFormat1, q);
 562
 563     error = TA_read_coverage_table(Mark1Coverage, &cov, sfnt, font);
 564     if (error)
 565       return error;
 566
 567     q = Mark1Array;
 568     VALUE(Mark1Count, q);
 569
 570     /* sanity check */
 571     if (cov.num_glyph_idxs != Mark1Count)
 572     {
 573       error = FT_Err_Invalid_Table;
 574       goto Fail;
 575     }
 576
 577     /* loop over q */
 578     for (i = 0; i < Mark1Count; i++)
 579     {
 580       FT_UShort glyph_idx = cov.glyph_idxs[i];
 581       FT_Byte* Mark1Anchor;
 582
 583
 584       q += 2; /* skip Class */
 585       OFFSET(Mark1Anchor, Mark1Array, q);
 586       error = TA_update_anchor(Mark1Anchor, glyph_idx, sfnt, font);
 587       if (error)
 588         return error;
 589     }
 590
 591     free(cov.glyph_idxs);
 592
 593     error = TA_read_coverage_table(Mark2Coverage, &cov, sfnt, font);
 594     if (error)
 595       return error;
 596
 597     q = Mark2Array;
 598     VALUE(Mark2Count, q);
 599
 600     /* sanity check */
 601     if (cov.num_glyph_idxs != Mark2Count)
 602     {
 603       error = FT_Err_Invalid_Table;
 604       goto Fail;
 605     }
 606
 607     /* loop over q */
 608     for (i = 0; i < Mark2Count; i++)
 609     {
 610       FT_UShort glyph_idx = cov.glyph_idxs[i];
 611       FT_UShort cc = ClassCount;
 612
 613
 614       for (; cc > 0; cc--)
 615       {
 616         FT_Byte* Mark2Anchor;
 617
 618
 619         OFFSET(Mark2Anchor, Mark2Array, q);
 620         error = TA_update_anchor(Mark2Anchor, glyph_idx, sfnt, font);
 621         if (error)
 622           return error;
 623       }
 624     }
 625
 626     free(cov.glyph_idxs);
 627     cov.glyph_idxs = NULL;
 628   }
 629
 630   return TA_Err_Ok;
 631
 632 Fail:
 633   free(cov.glyph_idxs);
 634   return error;
 635 }
 636
 637
 638 #define Cursive 3
 639 #define MarkBase 4
 640 #define MarkLig 5
 641 #define MarkMark 6
 642
 643 FT_Error
 644 TA_sfnt_update_GPOS_table(SFNT* sfnt,
 645                           FONT* font)
 646 {
 647   SFNT_Table* GPOS_table;
 648   FT_Byte* buf;
 649
 650   FT_Byte* LookupList;
 651   FT_UShort LookupCount;
 652   FT_Byte* p;
 653
 654
 655   if (sfnt->GPOS_idx == MISSING)
 656     return TA_Err_Ok;
 657
 658   GPOS_table = &font->tables[sfnt->GPOS_idx];
 659   buf = GPOS_table->buf;
 660   p = buf;
 661
 662   if (GPOS_table->processed)
 663     return TA_Err_Ok;
 664
 665   p += 8; /* skip Version, ScriptList, and FeatureList */
 666   OFFSET(LookupList, buf, p);
 667
 668   p = LookupList;
 669   VALUE(LookupCount, p);
 670
 671   /* loop over p */
 672   for (; LookupCount > 0; LookupCount--)
 673   {
 674     FT_Byte* Lookup;
 675     FT_UShort LookupType;
 676     FT_Byte* q;
 677     FT_Error error = TA_Err_Ok;
 678
 679
 680     OFFSET(Lookup, LookupList, p);
 681
 682     q = Lookup;
 683     VALUE(LookupType, q);
 684
 685     if (LookupType == Cursive)
 686       error = TA_handle_cursive_lookup(Lookup, q, sfnt, font);
 687     else if (LookupType == MarkBase)
 688       error = TA_handle_markbase_lookup(Lookup, q, sfnt, font);
 689     else if (LookupType == MarkLig)
 690       error = TA_handle_marklig_lookup(Lookup, q, sfnt, font);
 691     else if (LookupType == MarkMark)
 692       error = TA_handle_markmark_lookup(Lookup, q, sfnt, font);
 693
 694     if (error)
 695       return error;
 696   }
 697
 698   GPOS_table->checksum = TA_table_compute_checksum(GPOS_table->buf,
 699                                                    GPOS_table->len);
 700   GPOS_table->processed = 1;
 701
 702   return TA_Err_Ok;
 703 }
 704
 705 /* end of tagpos.c */