src/hb-ot-layout.cc

   1 /*
   2  * Copyright (C) 1998-2004  David Turner and Werner Lemberg
   3  * Copyright (C) 2006  Behdad Esfahbod
   4  * Copyright (C) 2007,2008,2009  Red Hat, Inc.
   5  *
   6  *  This is part of HarfBuzz, an OpenType Layout engine library.
   7  *
   8  * Permission is hereby granted, without written agreement and without
   9  * license or royalty fees, to use, copy, modify, and distribute this
  10  * software and its documentation for any purpose, provided that the
  11  * above copyright notice and the following two paragraphs appear in
  12  * all copies of this software.
  13  *
  14  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
  15  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
  16  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
  17  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
  18  * DAMAGE.
  19  *
  20  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
  21  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
  22  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
  23  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
  24  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
  25  *
  26  * Red Hat Author(s): Behdad Esfahbod
  27  */
  28
  29 #define HB_OT_LAYOUT_CC
  30
  31 /* XXX */
  32 #include "hb-buffer-private.h"
  33
  34 #include "hb-ot-layout.h"
  35 #include "hb-ot-layout-private.h"
  36
  37 #include "hb-ot-layout-open-private.h"
  38 #include "hb-ot-layout-gdef-private.h"
  39 #include "hb-ot-layout-gsub-private.h"
  40 #include "hb-ot-layout-gpos-private.h"
  41
  42
  43 #include <stdlib.h>
  44 #include <string.h>
  45
  46
  47 hb_ot_layout_t *
  48 hb_ot_layout_create (void)
  49 {
  50   hb_ot_layout_t *layout = (hb_ot_layout_t *) calloc (1, sizeof (hb_ot_layout_t));
  51
  52   layout->gdef = &Null(GDEF);
  53   layout->gsub = &Null(GSUB);
  54   layout->gpos = &Null(GPOS);
  55
  56   return layout;
  57 }
  58
  59 hb_bool_t
  60 hb_ot_layout_has_substitution (hb_ot_layout_t *layout)
  61 {
  62   return layout->gsub != &Null(GSUB);
  63 }
  64
  65 hb_bool_t
  66 hb_ot_layout_has_positioning (hb_ot_layout_t *layout)
  67 {
  68   return layout->gpos != &Null(GPOS);
  69 }
  70
  71 hb_ot_layout_t *
  72 hb_ot_layout_create_for_data (const char *font_data,
  73                               int         face_index)
  74 {
  75   hb_ot_layout_t *layout;
  76
  77   if (HB_UNLIKELY (font_data == NULL))
  78     return hb_ot_layout_create ();
  79
  80   layout = (hb_ot_layout_t *) calloc (1, sizeof (hb_ot_layout_t));
  81
  82   const OpenTypeFontFile &font = OpenTypeFontFile::get_for_data (font_data);
  83   const OpenTypeFontFace &face = font.get_face (face_index);
  84
  85   layout->gdef = &GDEF::get_for_data (font.get_table_data (face.get_table_by_tag (GDEF::Tag)));
  86   layout->gsub = &GSUB::get_for_data (font.get_table_data (face.get_table_by_tag (GSUB::Tag)));
  87   layout->gpos = &GPOS::get_for_data (font.get_table_data (face.get_table_by_tag (GPOS::Tag)));
  88
  89   return layout;
  90 }
  91
  92 hb_ot_layout_t *
  93 hb_ot_layout_create_for_tables (const char *gdef_data,
  94                                 const char *gsub_data,
  95                                 const char *gpos_data)
  96 {
  97   hb_ot_layout_t *layout;
  98
  99   if (HB_UNLIKELY (gdef_data == NULL && gsub_data == NULL && gpos_data == NULL))
 100     return hb_ot_layout_create ();
 101
 102   layout = (hb_ot_layout_t *) calloc (1, sizeof (hb_ot_layout_t));
 103
 104   layout->gdef = &GDEF::get_for_data (gdef_data);
 105   layout->gsub = &GSUB::get_for_data (gsub_data);
 106   layout->gpos = &GPOS::get_for_data (gpos_data);
 107
 108   return layout;
 109 }
 110
 111 void
 112 hb_ot_layout_destroy (hb_ot_layout_t *layout)
 113 {
 114   free (layout);
 115 }
 116
 117 void
 118 hb_ot_layout_set_hinting (hb_ot_layout_t *layout,
 119                           hb_bool_t hinted)
 120 {
 121   layout->gpos_info.dvi = !hinted;
 122 }
 123
 124 void
 125 hb_ot_layout_set_scale (hb_ot_layout_t *layout,
 126                         hb_16dot16_t x_scale, hb_16dot16_t y_scale)
 127 {
 128   layout->gpos_info.x_scale = x_scale;
 129   layout->gpos_info.y_scale = y_scale;
 130 }
 131
 132 void
 133 hb_ot_layout_set_ppem (hb_ot_layout_t *layout,
 134                        unsigned int x_ppem, unsigned int y_ppem)
 135 {
 136   layout->gpos_info.x_ppem = x_ppem;
 137   layout->gpos_info.y_ppem = y_ppem;
 138 }
 139
 140
 141 /*
 142  * GDEF
 143  */
 144
 145 /* TODO the public class_t is a mess */
 146
 147 hb_bool_t
 148 hb_ot_layout_has_font_glyph_classes (hb_ot_layout_t *layout)
 149 {
 150   return layout->gdef->has_glyph_classes ();
 151 }
 152
 153 HB_INTERNAL hb_bool_t
 154 _hb_ot_layout_has_new_glyph_classes (hb_ot_layout_t *layout)
 155 {
 156   return layout->new_gdef.len > 0;
 157 }
 158
 159 HB_INTERNAL unsigned int
 160 _hb_ot_layout_get_glyph_property (hb_ot_layout_t *layout,
 161                                   hb_codepoint_t  glyph)
 162 {
 163   hb_ot_layout_class_t klass;
 164
 165   klass = layout->gdef->get_glyph_class (glyph);
 166
 167   if (!klass && glyph < layout->new_gdef.len)
 168     klass = layout->new_gdef.klasses[glyph];
 169
 170   switch (klass) {
 171   default:
 172   case GDEF::UnclassifiedGlyph: return HB_OT_LAYOUT_GLYPH_CLASS_UNCLASSIFIED;
 173   case GDEF::BaseGlyph:         return HB_OT_LAYOUT_GLYPH_CLASS_BASE_GLYPH;
 174   case GDEF::LigatureGlyph:     return HB_OT_LAYOUT_GLYPH_CLASS_LIGATURE;
 175   case GDEF::ComponentGlyph:    return HB_OT_LAYOUT_GLYPH_CLASS_COMPONENT;
 176   case GDEF::MarkGlyph:
 177         /* TODO old harfbuzz doesn't always parse mark attachments as it says it was
 178          * introduced without a version bump, so it may not be safe */
 179         klass = layout->gdef->get_mark_attachment_type (glyph);
 180         return HB_OT_LAYOUT_GLYPH_CLASS_MARK + (klass << 8);
 181   }
 182 }
 183
 184 HB_INTERNAL hb_bool_t
 185 _hb_ot_layout_check_glyph_property (hb_ot_layout_t  *layout,
 186                                     hb_glyph_info_t *ginfo,
 187                                     unsigned int     lookup_flags,
 188                                     unsigned int    *property_out)
 189 {
 190   unsigned int property;
 191
 192   if (ginfo->gproperty == HB_BUFFER_GLYPH_PROPERTIES_UNKNOWN)
 193     ginfo->gproperty = _hb_ot_layout_get_glyph_property (layout, ginfo->gindex);
 194   property = ginfo->gproperty;
 195   if (property_out)
 196     *property_out = property;
 197
 198   /* Not covered, if, for example, glyph class is ligature and
 199    * lookup_flags includes LookupFlags::IgnoreLigatures
 200    */
 201   if (property & lookup_flags)
 202     return false;
 203
 204   if (property & HB_OT_LAYOUT_GLYPH_CLASS_MARK)
 205   {
 206     /* If using mark filtering sets, the high short of
 207      * lookup_flags has the set index.
 208      */
 209     if (lookup_flags & LookupFlag::UseMarkFilteringSet)
 210       return layout->gdef->mark_set_covers (lookup_flags >> 16, ginfo->gindex);
 211
 212     /* The second byte of lookup_flags has the meaning
 213      * "ignore marks of attachment type different than
 214      * the attachment type specified."
 215      */
 216     if (lookup_flags & LookupFlag::MarkAttachmentType && property & LookupFlag::MarkAttachmentType)
 217       return (lookup_flags & LookupFlag::MarkAttachmentType) == (property & LookupFlag::MarkAttachmentType);
 218   }
 219
 220   return true;
 221 }
 222
 223 HB_INTERNAL hb_bool_t
 224 _hb_ot_layout_skip_mark (hb_ot_layout_t  *layout,
 225                          hb_glyph_info_t *ginfo,
 226                          unsigned int     lookup_flags,
 227                          unsigned int    *property_out)
 228 {
 229   unsigned int property;
 230
 231   if (ginfo->gproperty == HB_BUFFER_GLYPH_PROPERTIES_UNKNOWN)
 232     ginfo->gproperty = _hb_ot_layout_get_glyph_property (layout, ginfo->gindex);
 233   property = ginfo->gproperty;
 234   if (property_out)
 235     *property_out = property;
 236
 237   if (property & HB_OT_LAYOUT_GLYPH_CLASS_MARK)
 238   {
 239     /* Skip mark if lookup_flags includes LookupFlags::IgnoreMarks */
 240     if (lookup_flags & LookupFlag::IgnoreMarks)
 241       return true;
 242
 243     /* If using mark filtering sets, the high short of lookup_flags has the set index. */
 244     if (lookup_flags & LookupFlag::UseMarkFilteringSet)
 245       return !layout->gdef->mark_set_covers (lookup_flags >> 16, ginfo->gindex);
 246
 247     /* The second byte of lookup_flags has the meaning "ignore marks of attachment type
 248      * different than the attachment type specified." */
 249     if (lookup_flags & LookupFlag::MarkAttachmentType && property & LookupFlag::MarkAttachmentType)
 250       return (lookup_flags & LookupFlag::MarkAttachmentType) != (property & LookupFlag::MarkAttachmentType);
 251   }
 252
 253   return false;
 254 }
 255
 256 HB_INTERNAL void
 257 _hb_ot_layout_set_glyph_property (hb_ot_layout_t *layout,
 258                                   hb_codepoint_t  glyph,
 259                                   unsigned int    property)
 260 { hb_ot_layout_set_glyph_class (layout, glyph, (hb_ot_layout_glyph_class_t) (property & 0xff)); }
 261
 262
 263 hb_ot_layout_glyph_class_t
 264 hb_ot_layout_get_glyph_class (hb_ot_layout_t *layout,
 265                               hb_codepoint_t  glyph)
 266 { return (hb_ot_layout_glyph_class_t) (_hb_ot_layout_get_glyph_property (layout, glyph) & 0xff); }
 267
 268 void
 269 hb_ot_layout_set_glyph_class (hb_ot_layout_t             *layout,
 270                               hb_codepoint_t              glyph,
 271                               hb_ot_layout_glyph_class_t  klass)
 272 {
 273   /* TODO optimize this, similar to old harfbuzz code for example */
 274
 275   hb_ot_layout_class_t gdef_klass;
 276   int len = layout->new_gdef.len;
 277
 278   if (HB_UNLIKELY (glyph > 65535))
 279     return;
 280
 281   if (glyph >= len) {
 282     int new_len;
 283     unsigned char *new_klasses;
 284
 285     new_len = len == 0 ? 120 : 2 * len;
 286     if (new_len > 65535)
 287       new_len = 65535;
 288     new_klasses = (unsigned char *) realloc (layout->new_gdef.klasses, new_len * sizeof (unsigned char));
 289
 290     if (HB_UNLIKELY (!new_klasses))
 291       return;
 292
 293     memset (new_klasses + len, 0, new_len - len);
 294
 295     layout->new_gdef.klasses = new_klasses;
 296     layout->new_gdef.len = new_len;
 297   }
 298
 299   switch (klass) {
 300   default:
 301   case HB_OT_LAYOUT_GLYPH_CLASS_UNCLASSIFIED:   gdef_klass = GDEF::UnclassifiedGlyph;   break;
 302   case HB_OT_LAYOUT_GLYPH_CLASS_BASE_GLYPH:     gdef_klass = GDEF::BaseGlyph;           break;
 303   case HB_OT_LAYOUT_GLYPH_CLASS_LIGATURE:       gdef_klass = GDEF::LigatureGlyph;       break;
 304   case HB_OT_LAYOUT_GLYPH_CLASS_MARK:           gdef_klass = GDEF::MarkGlyph;           break;
 305   case HB_OT_LAYOUT_GLYPH_CLASS_COMPONENT:      gdef_klass = GDEF::ComponentGlyph;      break;
 306   }
 307
 308   layout->new_gdef.klasses[glyph] = gdef_klass;
 309   return;
 310 }
 311
 312 void
 313 hb_ot_layout_build_glyph_classes (hb_ot_layout_t *layout,
 314                                   uint16_t        num_total_glyphs,
 315                                   hb_codepoint_t *glyphs,
 316                                   unsigned char  *klasses,
 317                                   uint16_t        count)
 318 {
 319   if (HB_UNLIKELY (!count || !glyphs || !klasses))
 320     return;
 321
 322   if (layout->new_gdef.len == 0) {
 323     layout->new_gdef.klasses = (unsigned char *) calloc (num_total_glyphs, sizeof (unsigned char));
 324     layout->new_gdef.len = count;
 325   }
 326
 327   for (unsigned int i = 0; i < count; i++)
 328     hb_ot_layout_set_glyph_class (layout, glyphs[i], (hb_ot_layout_glyph_class_t) klasses[i]);
 329 }
 330
 331 hb_bool_t
 332 hb_ot_layout_get_attach_points (hb_ot_layout_t *layout,
 333                                 hb_codepoint_t  glyph,
 334                                 unsigned int   *point_count /* IN/OUT */,
 335                                 unsigned int   *point_array /* OUT */)
 336 {
 337   return layout->gdef->get_attach_points (glyph, point_count, point_array);
 338 }
 339
 340 hb_bool_t
 341 hb_ot_layout_get_lig_carets (hb_ot_layout_t *layout,
 342                              hb_codepoint_t  glyph,
 343                              unsigned int   *caret_count /* IN/OUT */,
 344                              int            *caret_array /* OUT */)
 345 {
 346   return layout->gdef->get_lig_carets (layout, glyph, caret_count, caret_array);
 347 }
 348
 349 /*
 350  * GSUB/GPOS
 351  */
 352
 353 static const GSUBGPOS&
 354 get_gsubgpos_table (hb_ot_layout_t            *layout,
 355                     hb_ot_layout_table_type_t  table_type)
 356 {
 357   switch (table_type) {
 358     case HB_OT_LAYOUT_TABLE_TYPE_GSUB: return *(layout->gsub);
 359     case HB_OT_LAYOUT_TABLE_TYPE_GPOS: return *(layout->gpos);
 360     default:                           return Null(GSUBGPOS);
 361   }
 362 }
 363
 364
 365 unsigned int
 366 hb_ot_layout_table_get_script_count (hb_ot_layout_t            *layout,
 367                                      hb_ot_layout_table_type_t  table_type)
 368 {
 369   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 370
 371   return g.get_script_count ();
 372 }
 373
 374 hb_tag_t
 375 hb_ot_layout_table_get_script_tag (hb_ot_layout_t            *layout,
 376                                    hb_ot_layout_table_type_t  table_type,
 377                                    unsigned int               script_index)
 378 {
 379   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 380
 381   return g.get_script_tag (script_index);
 382 }
 383
 384 hb_bool_t
 385 hb_ot_layout_table_find_script (hb_ot_layout_t            *layout,
 386                                 hb_ot_layout_table_type_t  table_type,
 387                                 hb_tag_t                   script_tag,
 388                                 unsigned int              *script_index)
 389 {
 390   ASSERT_STATIC (NO_INDEX == HB_OT_LAYOUT_NO_SCRIPT_INDEX);
 391   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 392
 393   if (g.find_script_index (script_tag, script_index))
 394     return TRUE;
 395
 396   /* try finding 'DFLT' */
 397   if (g.find_script_index (HB_OT_LAYOUT_TAG_DEFAULT_SCRIPT, script_index))
 398     return FALSE;
 399
 400   /* try with 'dflt'; MS site has had typos and many fonts use it now :( */
 401   if (g.find_script_index (HB_OT_LAYOUT_TAG_DEFAULT_LANGUAGE, script_index))
 402     return FALSE;
 403
 404   if (script_index) *script_index = HB_OT_LAYOUT_NO_SCRIPT_INDEX;
 405   return FALSE;
 406 }
 407
 408 unsigned int
 409 hb_ot_layout_table_get_feature_count (hb_ot_layout_t            *layout,
 410                                       hb_ot_layout_table_type_t  table_type)
 411 {
 412   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 413
 414   return g.get_feature_count ();
 415 }
 416
 417 hb_tag_t
 418 hb_ot_layout_table_get_feature_tag (hb_ot_layout_t            *layout,
 419                                     hb_ot_layout_table_type_t  table_type,
 420                                     unsigned int               feature_index)
 421 {
 422   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 423
 424   return g.get_feature_tag (feature_index);
 425 }
 426
 427 hb_bool_t
 428 hb_ot_layout_table_find_feature (hb_ot_layout_t            *layout,
 429                                  hb_ot_layout_table_type_t  table_type,
 430                                  hb_tag_t                   feature_tag,
 431                                  unsigned int              *feature_index)
 432 {
 433   ASSERT_STATIC (NO_INDEX == HB_OT_LAYOUT_NO_FEATURE_INDEX);
 434   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 435
 436   if (g.find_feature_index (feature_tag, feature_index))
 437     return TRUE;
 438
 439   if (feature_index) *feature_index = HB_OT_LAYOUT_NO_FEATURE_INDEX;
 440   return FALSE;
 441 }
 442
 443 unsigned int
 444 hb_ot_layout_table_get_lookup_count (hb_ot_layout_t            *layout,
 445                                      hb_ot_layout_table_type_t  table_type)
 446 {
 447   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 448
 449   return g.get_lookup_count ();
 450 }
 451
 452
 453 unsigned int
 454 hb_ot_layout_script_get_language_count (hb_ot_layout_t            *layout,
 455                                         hb_ot_layout_table_type_t  table_type,
 456                                         unsigned int               script_index)
 457 {
 458   const Script &s = get_gsubgpos_table (layout, table_type).get_script (script_index);
 459
 460   return s.get_lang_sys_count ();
 461 }
 462
 463 hb_tag_t
 464 hb_ot_layout_script_get_language_tag (hb_ot_layout_t            *layout,
 465                                       hb_ot_layout_table_type_t  table_type,
 466                                       unsigned int               script_index,
 467                                       unsigned int               language_index)
 468 {
 469   const Script &s = get_gsubgpos_table (layout, table_type).get_script (script_index);
 470
 471   return s.get_lang_sys_tag (language_index);
 472 }
 473
 474 hb_bool_t
 475 hb_ot_layout_script_find_language (hb_ot_layout_t            *layout,
 476                                    hb_ot_layout_table_type_t  table_type,
 477                                    unsigned int               script_index,
 478                                    hb_tag_t                   language_tag,
 479                                    unsigned int              *language_index)
 480 {
 481   ASSERT_STATIC (NO_INDEX == HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX);
 482   const Script &s = get_gsubgpos_table (layout, table_type).get_script (script_index);
 483
 484   if (s.find_lang_sys_index (language_tag, language_index))
 485     return TRUE;
 486
 487   /* try with 'dflt'; MS site has had typos and many fonts use it now :( */
 488   if (s.find_lang_sys_index (HB_OT_LAYOUT_TAG_DEFAULT_LANGUAGE, language_index))
 489     return FALSE;
 490
 491   if (language_index) *language_index = HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX;
 492   return FALSE;
 493 }
 494
 495 hb_bool_t
 496 hb_ot_layout_language_get_required_feature_index (hb_ot_layout_t            *layout,
 497                                                   hb_ot_layout_table_type_t  table_type,
 498                                                   unsigned int               script_index,
 499                                                   unsigned int               language_index,
 500                                                   unsigned int              *feature_index)
 501 {
 502   const LangSys &l = get_gsubgpos_table (layout, table_type).get_script (script_index).get_lang_sys (language_index);
 503
 504   if (feature_index) *feature_index = l.get_required_feature_index ();
 505
 506   return l.has_required_feature ();
 507 }
 508
 509 unsigned int
 510 hb_ot_layout_language_get_feature_count (hb_ot_layout_t            *layout,
 511                                          hb_ot_layout_table_type_t  table_type,
 512                                          unsigned int               script_index,
 513                                          unsigned int               language_index)
 514 {
 515   const LangSys &l = get_gsubgpos_table (layout, table_type).get_script (script_index).get_lang_sys (language_index);
 516
 517   return l.get_feature_count ();
 518 }
 519
 520 unsigned int
 521 hb_ot_layout_language_get_feature_index (hb_ot_layout_t            *layout,
 522                                          hb_ot_layout_table_type_t  table_type,
 523                                          unsigned int               script_index,
 524                                          unsigned int               language_index,
 525                                          unsigned int               num_feature)
 526 {
 527   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 528   const LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
 529
 530   return l.get_feature_index (num_feature);
 531 }
 532
 533 hb_tag_t
 534 hb_ot_layout_language_get_feature_tag (hb_ot_layout_t            *layout,
 535                                        hb_ot_layout_table_type_t  table_type,
 536                                        unsigned int               script_index,
 537                                        unsigned int               language_index,
 538                                        unsigned int               num_feature)
 539 {
 540   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 541   const LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
 542   unsigned int feature_index = l.get_feature_index (num_feature);
 543
 544   return g.get_feature_tag (feature_index);
 545 }
 546
 547
 548 hb_bool_t
 549 hb_ot_layout_language_find_feature (hb_ot_layout_t            *layout,
 550                                     hb_ot_layout_table_type_t  table_type,
 551                                     unsigned int               script_index,
 552                                     unsigned int               language_index,
 553                                     hb_tag_t                   feature_tag,
 554                                     unsigned int              *feature_index)
 555 {
 556   ASSERT_STATIC (NO_INDEX == HB_OT_LAYOUT_NO_FEATURE_INDEX);
 557   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 558   const LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
 559
 560   unsigned int num_features = l.get_feature_count ();
 561   for (unsigned int i = 0; i < num_features; i++) {
 562     unsigned int f_index = l.get_feature_index (i);
 563
 564     if (feature_tag == g.get_feature_tag (f_index)) {
 565       if (feature_index) *feature_index = f_index;
 566       return TRUE;
 567     }
 568   }
 569
 570   if (feature_index) *feature_index = HB_OT_LAYOUT_NO_FEATURE_INDEX;
 571   return FALSE;
 572 }
 573
 574 unsigned int
 575 hb_ot_layout_feature_get_lookup_count (hb_ot_layout_t            *layout,
 576                                        hb_ot_layout_table_type_t  table_type,
 577                                        unsigned int               feature_index)
 578 {
 579   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 580   const Feature &f = g.get_feature (feature_index);
 581
 582   return f.get_lookup_count ();
 583 }
 584
 585 unsigned int
 586 hb_ot_layout_feature_get_lookup_index (hb_ot_layout_t            *layout,
 587                                        hb_ot_layout_table_type_t  table_type,
 588                                        unsigned int               feature_index,
 589                                        unsigned int               num_lookup)
 590 {
 591   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 592   const Feature &f = g.get_feature (feature_index);
 593
 594   return f.get_lookup_index (num_lookup);
 595 }
 596
 597 /*
 598  * GSUB
 599  */
 600
 601 hb_bool_t
 602 hb_ot_layout_substitute_lookup (hb_ot_layout_t              *layout,
 603                                 hb_buffer_t                 *buffer,
 604                                 unsigned int                 lookup_index,
 605                                 hb_ot_layout_feature_mask_t  mask)
 606 {
 607   return layout->gsub->substitute_lookup (layout, buffer, lookup_index, mask);
 608 }
 609
 610 /*
 611  * GPOS
 612  */
 613
 614 hb_bool_t
 615 hb_ot_layout_position_lookup   (hb_ot_layout_t              *layout,
 616                                 hb_buffer_t                 *buffer,
 617                                 unsigned int                 lookup_index,
 618                                 hb_ot_layout_feature_mask_t  mask)
 619 {
 620   return layout->gpos->position_lookup (layout, buffer, lookup_index, mask);
 621 }