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 #include "hb-ot-layout.h"
  32 #include "hb-ot-layout-private.h"
  33
  34 #include "hb-ot-layout-open-private.h"
  35 #include "hb-ot-layout-gdef-private.h"
  36 #include "hb-ot-layout-gsub-private.h"
  37
  38 /* XXX */
  39 #include "harfbuzz-buffer-private.h"
  40
  41 #include <stdlib.h>
  42 #include <string.h>
  43
  44
  45 hb_ot_layout_t *
  46 hb_ot_layout_create (void)
  47 {
  48   hb_ot_layout_t *layout = (hb_ot_layout_t *) calloc (1, sizeof (hb_ot_layout_t));
  49
  50   layout->gdef = &Null(GDEF);
  51   layout->gsub = &Null(GSUB);
  52   layout->gpos = &/*XXX*/Null(GSUBGPOS);
  53
  54   return layout;
  55 }
  56
  57 hb_ot_layout_t *
  58 hb_ot_layout_create_for_data (const char *font_data,
  59                               int         face_index)
  60 {
  61   hb_ot_layout_t *layout;
  62
  63   if (HB_UNLIKELY (font_data == NULL))
  64     return hb_ot_layout_create ();
  65
  66   layout = (hb_ot_layout_t *) calloc (1, sizeof (hb_ot_layout_t));
  67
  68   const OpenTypeFontFile &font = OpenTypeFontFile::get_for_data (font_data);
  69   const OpenTypeFontFace &face = font.get_face (face_index);
  70
  71   layout->gdef = &GDEF::get_for_data (font.get_table_data (face.get_table_by_tag (GDEF::Tag)));
  72   layout->gsub = &GSUB::get_for_data (font.get_table_data (face.get_table_by_tag (GSUB::Tag)));
  73   layout->gpos = &/*XXX*/GSUBGPOS::get_for_data (font.get_table_data (face.get_table_by_tag (/*XXX*/GSUBGPOS::GPOSTag)));
  74
  75   return layout;
  76 }
  77
  78 void
  79 hb_ot_layout_destroy (hb_ot_layout_t *layout)
  80 {
  81   free (layout);
  82 }
  83
  84 /*
  85  * GDEF
  86  */
  87
  88 /* XXX the public class_t is a mess */
  89
  90 hb_bool_t
  91 hb_ot_layout_has_font_glyph_classes (hb_ot_layout_t *layout)
  92 {
  93   return layout->gdef->has_glyph_classes ();
  94 }
  95
  96 HB_OT_LAYOUT_INTERNAL hb_bool_t
  97 _hb_ot_layout_has_new_glyph_classes (hb_ot_layout_t *layout)
  98 {
  99   return layout->new_gdef.len > 0;
 100 }
 101
 102 HB_OT_LAYOUT_INTERNAL unsigned int
 103 _hb_ot_layout_get_glyph_property (hb_ot_layout_t *layout,
 104                                   hb_codepoint_t  glyph)
 105 {
 106   hb_ot_layout_class_t klass;
 107
 108   /* TODO old harfbuzz doesn't always parse mark attachments as it says it was
 109    * introduced without a version bump, so it may not be safe */
 110   klass = layout->gdef->get_mark_attachment_type (glyph);
 111   if (klass)
 112     return klass << 8;
 113
 114   klass = layout->gdef->get_glyph_class (glyph);
 115
 116   if (!klass && glyph < layout->new_gdef.len)
 117     klass = layout->new_gdef.klasses[glyph];
 118
 119   switch (klass) {
 120   default:
 121   case GDEF::UnclassifiedGlyph: return HB_OT_LAYOUT_GLYPH_CLASS_UNCLASSIFIED;
 122   case GDEF::BaseGlyph:         return HB_OT_LAYOUT_GLYPH_CLASS_BASE_GLYPH;
 123   case GDEF::LigatureGlyph:     return HB_OT_LAYOUT_GLYPH_CLASS_LIGATURE;
 124   case GDEF::MarkGlyph:         return HB_OT_LAYOUT_GLYPH_CLASS_MARK;
 125   case GDEF::ComponentGlyph:    return HB_OT_LAYOUT_GLYPH_CLASS_COMPONENT;
 126   }
 127 }
 128
 129 HB_OT_LAYOUT_INTERNAL hb_bool_t
 130 _hb_ot_layout_check_glyph_property (hb_ot_layout_t *layout,
 131                                     HB_GlyphItem    gitem,
 132                                     unsigned int    lookup_flags,
 133                                     unsigned int   *property)
 134 {
 135   hb_ot_layout_glyph_class_t basic_glyph_class;
 136   unsigned int desired_attachment_class;
 137
 138   if (gitem->gproperty == HB_BUFFER_GLYPH_PROPERTIES_UNKNOWN)
 139   {
 140     gitem->gproperty = *property = _hb_ot_layout_get_glyph_property (layout, gitem->gindex);
 141     if (gitem->gproperty == HB_OT_LAYOUT_GLYPH_CLASS_UNCLASSIFIED)
 142       return false;
 143   }
 144
 145   *property = gitem->gproperty;
 146
 147   /* If the glyph was found in the MarkAttachmentClass table,
 148    * then that class value is the high byte of the result,
 149    * otherwise the low byte contains the basic type of the glyph
 150    * as defined by the GlyphClassDef table.
 151    */
 152   if (*property & LookupFlag::MarkAttachmentType)
 153     basic_glyph_class = HB_OT_LAYOUT_GLYPH_CLASS_MARK;
 154   else
 155     basic_glyph_class = (hb_ot_layout_glyph_class_t) *property;
 156
 157   /* Not covered, if, for example, basic_glyph_class
 158    * is HB_GDEF_LIGATURE and lookup_flags includes LookupFlags::IgnoreLigatures
 159    */
 160   if (lookup_flags & basic_glyph_class)
 161     return false;
 162
 163   /* The high byte of lookup_flags has the meaning
 164    * "ignore marks of attachment type different than
 165    * the attachment type specified."
 166    */
 167   desired_attachment_class = lookup_flags & LookupFlag::MarkAttachmentType;
 168   if (desired_attachment_class)
 169   {
 170     if (basic_glyph_class == HB_OT_LAYOUT_GLYPH_CLASS_MARK &&
 171         *property != desired_attachment_class)
 172       return false;
 173   }
 174
 175   return true;
 176 }
 177
 178 HB_OT_LAYOUT_INTERNAL void
 179 _hb_ot_layout_set_glyph_property (hb_ot_layout_t *layout,
 180                                   hb_codepoint_t  glyph,
 181                                   unsigned int    property)
 182 {
 183   hb_ot_layout_glyph_class_t klass;
 184
 185   if (property & LookupFlag::MarkAttachmentType)
 186     klass = HB_OT_LAYOUT_GLYPH_CLASS_MARK;
 187   else
 188     klass = (hb_ot_layout_glyph_class_t) property;
 189
 190   hb_ot_layout_set_glyph_class (layout, glyph, klass);
 191 }
 192
 193
 194 hb_ot_layout_glyph_class_t
 195 hb_ot_layout_get_glyph_class (hb_ot_layout_t *layout,
 196                               hb_codepoint_t  glyph)
 197 {
 198   unsigned int property;
 199   hb_ot_layout_class_t klass;
 200
 201   property = _hb_ot_layout_get_glyph_property (layout, glyph);
 202
 203   if (property & LookupFlag::MarkAttachmentType)
 204     return HB_OT_LAYOUT_GLYPH_CLASS_MARK;
 205
 206   return (hb_ot_layout_glyph_class_t) property;
 207 }
 208
 209 void
 210 hb_ot_layout_set_glyph_class (hb_ot_layout_t             *layout,
 211                               hb_codepoint_t              glyph,
 212                               hb_ot_layout_glyph_class_t  klass)
 213 {
 214   /* TODO optimize this, similar to old harfbuzz code for example */
 215
 216   hb_ot_layout_class_t gdef_klass;
 217   int len = layout->new_gdef.len;
 218
 219   if (G_UNLIKELY (glyph > 65535))
 220     return;
 221
 222   if (glyph >= len) {
 223     int new_len;
 224     unsigned char *new_klasses;
 225
 226     new_len = len == 0 ? 120 : 2 * len;
 227     if (new_len > 65535)
 228       new_len = 65535;
 229     new_klasses = (unsigned char *) realloc (layout->new_gdef.klasses, new_len * sizeof (unsigned char));
 230
 231     if (G_UNLIKELY (!new_klasses))
 232       return;
 233
 234     memset (new_klasses + len, 0, new_len - len);
 235
 236     layout->new_gdef.klasses = new_klasses;
 237     layout->new_gdef.len = new_len;
 238   }
 239
 240   switch (klass) {
 241   default:
 242   case HB_OT_LAYOUT_GLYPH_CLASS_UNCLASSIFIED:   gdef_klass = GDEF::UnclassifiedGlyph;   break;
 243   case HB_OT_LAYOUT_GLYPH_CLASS_BASE_GLYPH:     gdef_klass = GDEF::BaseGlyph;           break;
 244   case HB_OT_LAYOUT_GLYPH_CLASS_LIGATURE:       gdef_klass = GDEF::LigatureGlyph;       break;
 245   case HB_OT_LAYOUT_GLYPH_CLASS_MARK:           gdef_klass = GDEF::MarkGlyph;           break;
 246   case HB_OT_LAYOUT_GLYPH_CLASS_COMPONENT:      gdef_klass = GDEF::ComponentGlyph;      break;
 247   }
 248
 249   layout->new_gdef.klasses[glyph] = gdef_klass;
 250   return;
 251 }
 252
 253 void
 254 hb_ot_layout_build_glyph_classes (hb_ot_layout_t *layout,
 255                                   uint16_t        num_total_glyphs,
 256                                   hb_codepoint_t *glyphs,
 257                                   unsigned char  *klasses,
 258                                   uint16_t        count)
 259 {
 260   if (G_UNLIKELY (!count || !glyphs || !klasses))
 261     return;
 262
 263   if (layout->new_gdef.len == 0) {
 264     layout->new_gdef.klasses = (unsigned char *) calloc (num_total_glyphs, sizeof (unsigned char));
 265     layout->new_gdef.len = count;
 266   }
 267
 268   for (unsigned int i = 0; i < count; i++)
 269     hb_ot_layout_set_glyph_class (layout, glyphs[i], (hb_ot_layout_glyph_class_t) klasses[i]);
 270 }
 271
 272 /*
 273  * GSUB/GPOS
 274  */
 275
 276 static const GSUBGPOS&
 277 get_gsubgpos_table (hb_ot_layout_t            *layout,
 278                     hb_ot_layout_table_type_t  table_type)
 279 {
 280   switch (table_type) {
 281     case HB_OT_LAYOUT_TABLE_TYPE_GSUB: return *(layout->gsub);
 282     case HB_OT_LAYOUT_TABLE_TYPE_GPOS: return *(layout->gpos);
 283     default:                           return Null(GSUBGPOS);
 284   }
 285 }
 286
 287
 288 unsigned int
 289 hb_ot_layout_table_get_script_count (hb_ot_layout_t            *layout,
 290                                      hb_ot_layout_table_type_t  table_type)
 291 {
 292   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 293
 294   return g.get_script_count ();
 295 }
 296
 297 hb_tag_t
 298 hb_ot_layout_table_get_script_tag (hb_ot_layout_t            *layout,
 299                                    hb_ot_layout_table_type_t  table_type,
 300                                    unsigned int               script_index)
 301 {
 302   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 303
 304   return g.get_script_tag (script_index);
 305 }
 306
 307 hb_bool_t
 308 hb_ot_layout_table_find_script (hb_ot_layout_t            *layout,
 309                                 hb_ot_layout_table_type_t  table_type,
 310                                 hb_tag_t                   script_tag,
 311                                 unsigned int              *script_index)
 312 {
 313   ASSERT_STATIC (NO_INDEX == HB_OT_LAYOUT_NO_SCRIPT_INDEX);
 314   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 315
 316   if (g.find_script_index (script_tag, script_index))
 317     return TRUE;
 318
 319   /* try finding 'DFLT' */
 320   if (g.find_script_index (HB_OT_LAYOUT_TAG_DEFAULT_SCRIPT, script_index))
 321     return FALSE;
 322
 323   /* try with 'dflt'; MS site has had typos and many fonts use it now :( */
 324   if (g.find_script_index (HB_OT_LAYOUT_TAG_DEFAULT_LANGUAGE, script_index))
 325     return FALSE;
 326
 327   if (script_index) *script_index = HB_OT_LAYOUT_NO_SCRIPT_INDEX;
 328   return FALSE;
 329 }
 330
 331 unsigned int
 332 hb_ot_layout_table_get_feature_count (hb_ot_layout_t            *layout,
 333                                       hb_ot_layout_table_type_t  table_type)
 334 {
 335   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 336
 337   return g.get_feature_count ();
 338 }
 339
 340 hb_tag_t
 341 hb_ot_layout_table_get_feature_tag (hb_ot_layout_t            *layout,
 342                                     hb_ot_layout_table_type_t  table_type,
 343                                     unsigned int               feature_index)
 344 {
 345   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 346
 347   return g.get_feature_tag (feature_index);
 348 }
 349
 350 hb_bool_t
 351 hb_ot_layout_table_find_feature (hb_ot_layout_t            *layout,
 352                                  hb_ot_layout_table_type_t  table_type,
 353                                  hb_tag_t                   feature_tag,
 354                                  unsigned int              *feature_index)
 355 {
 356   ASSERT_STATIC (NO_INDEX == HB_OT_LAYOUT_NO_FEATURE_INDEX);
 357   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 358
 359   if (g.find_feature_index (feature_tag, feature_index))
 360     return TRUE;
 361
 362   if (feature_index) *feature_index = HB_OT_LAYOUT_NO_FEATURE_INDEX;
 363   return FALSE;
 364 }
 365
 366 unsigned int
 367 hb_ot_layout_table_get_lookup_count (hb_ot_layout_t            *layout,
 368                                      hb_ot_layout_table_type_t  table_type)
 369 {
 370   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 371
 372   return g.get_lookup_count ();
 373 }
 374
 375
 376 unsigned int
 377 hb_ot_layout_script_get_language_count (hb_ot_layout_t            *layout,
 378                                         hb_ot_layout_table_type_t  table_type,
 379                                         unsigned int               script_index)
 380 {
 381   const Script &s = get_gsubgpos_table (layout, table_type).get_script (script_index);
 382
 383   return s.get_lang_sys_count ();
 384 }
 385
 386 hb_tag_t
 387 hb_ot_layout_script_get_language_tag (hb_ot_layout_t            *layout,
 388                                       hb_ot_layout_table_type_t  table_type,
 389                                       unsigned int               script_index,
 390                                       unsigned int               language_index)
 391 {
 392   const Script &s = get_gsubgpos_table (layout, table_type).get_script (script_index);
 393
 394   return s.get_lang_sys_tag (language_index);
 395 }
 396
 397 hb_bool_t
 398 hb_ot_layout_script_find_language (hb_ot_layout_t            *layout,
 399                                    hb_ot_layout_table_type_t  table_type,
 400                                    unsigned int               script_index,
 401                                    hb_tag_t                   language_tag,
 402                                    unsigned int              *language_index)
 403 {
 404   ASSERT_STATIC (NO_INDEX == HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX);
 405   const Script &s = get_gsubgpos_table (layout, table_type).get_script (script_index);
 406
 407   if (s.find_lang_sys_index (language_tag, language_index))
 408     return TRUE;
 409
 410   /* try with 'dflt'; MS site has had typos and many fonts use it now :( */
 411   if (s.find_lang_sys_index (HB_OT_LAYOUT_TAG_DEFAULT_LANGUAGE, language_index))
 412     return FALSE;
 413
 414   if (language_index) *language_index = HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX;
 415   return FALSE;
 416 }
 417
 418 hb_bool_t
 419 hb_ot_layout_language_get_required_feature_index (hb_ot_layout_t            *layout,
 420                                                   hb_ot_layout_table_type_t  table_type,
 421                                                   unsigned int               script_index,
 422                                                   unsigned int               language_index,
 423                                                   unsigned int              *feature_index)
 424 {
 425   const LangSys &l = get_gsubgpos_table (layout, table_type).get_script (script_index).get_lang_sys (language_index);
 426
 427   if (feature_index) *feature_index = l.get_required_feature_index ();
 428
 429   return l.has_required_feature ();
 430 }
 431
 432 unsigned int
 433 hb_ot_layout_language_get_feature_count (hb_ot_layout_t            *layout,
 434                                          hb_ot_layout_table_type_t  table_type,
 435                                          unsigned int               script_index,
 436                                          unsigned int               language_index)
 437 {
 438   const LangSys &l = get_gsubgpos_table (layout, table_type).get_script (script_index).get_lang_sys (language_index);
 439
 440   return l.get_feature_count ();
 441 }
 442
 443 unsigned int
 444 hb_ot_layout_language_get_feature_index (hb_ot_layout_t            *layout,
 445                                          hb_ot_layout_table_type_t  table_type,
 446                                          unsigned int               script_index,
 447                                          unsigned int               language_index,
 448                                          unsigned int               num_feature)
 449 {
 450   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 451   const LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
 452
 453   return l.get_feature_index (num_feature);
 454 }
 455
 456 hb_tag_t
 457 hb_ot_layout_language_get_feature_tag (hb_ot_layout_t            *layout,
 458                                        hb_ot_layout_table_type_t  table_type,
 459                                        unsigned int               script_index,
 460                                        unsigned int               language_index,
 461                                        unsigned int               num_feature)
 462 {
 463   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 464   const LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
 465   unsigned int feature_index = l.get_feature_index (num_feature);
 466
 467   return g.get_feature_tag (feature_index);
 468 }
 469
 470
 471 hb_bool_t
 472 hb_ot_layout_language_find_feature (hb_ot_layout_t            *layout,
 473                                     hb_ot_layout_table_type_t  table_type,
 474                                     unsigned int               script_index,
 475                                     unsigned int               language_index,
 476                                     hb_tag_t                   feature_tag,
 477                                     unsigned int              *feature_index)
 478 {
 479   ASSERT_STATIC (NO_INDEX == HB_OT_LAYOUT_NO_FEATURE_INDEX);
 480   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 481   const LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
 482
 483   unsigned int num_features = l.get_feature_count ();
 484   for (unsigned int i = 0; i < num_features; i++) {
 485     unsigned int f_index = l.get_feature_index (i);
 486
 487     if (feature_tag == g.get_feature_tag (f_index)) {
 488       if (feature_index) *feature_index = f_index;
 489       return TRUE;
 490     }
 491   }
 492
 493   if (feature_index) *feature_index = HB_OT_LAYOUT_NO_FEATURE_INDEX;
 494   return FALSE;
 495 }
 496
 497 unsigned int
 498 hb_ot_layout_feature_get_lookup_count (hb_ot_layout_t            *layout,
 499                                        hb_ot_layout_table_type_t  table_type,
 500                                        unsigned int               feature_index)
 501 {
 502   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 503   const Feature &f = g.get_feature (feature_index);
 504
 505   return f.get_lookup_count ();
 506 }
 507
 508 unsigned int
 509 hb_ot_layout_feature_get_lookup_index (hb_ot_layout_t            *layout,
 510                                        hb_ot_layout_table_type_t  table_type,
 511                                        unsigned int               feature_index,
 512                                        unsigned int               num_lookup)
 513 {
 514   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 515   const Feature &f = g.get_feature (feature_index);
 516
 517   return f.get_lookup_index (num_lookup);
 518 }
 519
 520 /*
 521  * GSUB
 522  */
 523
 524 hb_bool_t
 525 hb_ot_layout_substitute_lookup (hb_ot_layout_t              *layout,
 526                                 hb_buffer_t                 *buffer,
 527                                 unsigned int                 lookup_index,
 528                                 hb_ot_layout_feature_mask_t  mask)
 529 {
 530   return layout->gsub->substitute_lookup (layout, buffer, lookup_index, mask);
 531 }
 532
 533
 534
 535 /* XXX dupped, until he old code can be removed */
 536
 537 static HB_Error
 538 hb_buffer_duplicate_out_buffer( HB_Buffer buffer )
 539 {
 540   if ( !buffer->alt_string )
 541     {
 542       HB_Error error;
 543
 544       if ( ALLOC_ARRAY( buffer->alt_string, buffer->allocated, HB_GlyphItemRec ) )
 545         return error;
 546     }
 547
 548   buffer->out_string = buffer->alt_string;
 549   memcpy( buffer->out_string, buffer->in_string, buffer->out_length * sizeof (buffer->out_string[0]) );
 550   buffer->separate_out = TRUE;
 551
 552   return HB_Err_Ok;
 553 }
 554
 555
 556
 557 HB_INTERNAL HB_Error
 558 _hb_buffer_add_output_glyph_ids( HB_Buffer  buffer,
 559                               HB_UShort  num_in,
 560                               HB_UShort  num_out,
 561                               const GlyphID *glyph_data,
 562                               HB_UShort  component,
 563                               HB_UShort  ligID )
 564 {
 565   HB_Error  error;
 566   HB_UShort i;
 567   HB_UInt properties;
 568   HB_UInt cluster;
 569
 570   error = hb_buffer_ensure( buffer, buffer->out_pos + num_out );
 571   if ( error )
 572     return error;
 573
 574   if ( !buffer->separate_out )
 575     {
 576       error = hb_buffer_duplicate_out_buffer( buffer );
 577       if ( error )
 578         return error;
 579     }
 580
 581   properties = buffer->in_string[buffer->in_pos].properties;
 582   cluster = buffer->in_string[buffer->in_pos].cluster;
 583   if ( component == 0xFFFF )
 584     component = buffer->in_string[buffer->in_pos].component;
 585   if ( ligID == 0xFFFF )
 586     ligID = buffer->in_string[buffer->in_pos].ligID;
 587
 588   for ( i = 0; i < num_out; i++ )
 589   {
 590     HB_GlyphItem item = &buffer->out_string[buffer->out_pos + i];
 591
 592     item->gindex = glyph_data[i];
 593     item->properties = properties;
 594     item->cluster = cluster;
 595     item->component = component;
 596     item->ligID = ligID;
 597     item->gproperty = HB_GLYPH_PROPERTY_UNKNOWN;
 598   }
 599
 600   buffer->in_pos  += num_in;
 601   buffer->out_pos += num_out;
 602
 603   buffer->out_length = buffer->out_pos;
 604
 605   return HB_Err_Ok;
 606 }
 607