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 #include "hb-ot-layout-gpos-private.h"
  38
  39 /* XXX */
  40 #include "harfbuzz-buffer-private.h"
  41
  42 #include <stdlib.h>
  43 #include <string.h>
  44
  45
  46 hb_ot_layout_t *
  47 hb_ot_layout_create (void)
  48 {
  49   hb_ot_layout_t *layout = (hb_ot_layout_t *) calloc (1, sizeof (hb_ot_layout_t));
  50
  51   layout->gdef = &Null(GDEF);
  52   layout->gsub = &Null(GSUB);
  53   layout->gpos = &Null(GPOS);
  54
  55   return layout;
  56 }
  57
  58 hb_ot_layout_t *
  59 hb_ot_layout_create_for_data (const char *font_data,
  60                               int         face_index)
  61 {
  62   hb_ot_layout_t *layout;
  63
  64   if (HB_UNLIKELY (font_data == NULL))
  65     return hb_ot_layout_create ();
  66
  67   layout = (hb_ot_layout_t *) calloc (1, sizeof (hb_ot_layout_t));
  68
  69   const OpenTypeFontFile &font = OpenTypeFontFile::get_for_data (font_data);
  70   const OpenTypeFontFace &face = font.get_face (face_index);
  71
  72   layout->gdef = &GDEF::get_for_data (font.get_table_data (face.get_table_by_tag (GDEF::Tag)));
  73   layout->gsub = &GSUB::get_for_data (font.get_table_data (face.get_table_by_tag (GSUB::Tag)));
  74   layout->gpos = &GPOS::get_for_data (font.get_table_data (face.get_table_by_tag (GPOS::Tag)));
  75
  76   return layout;
  77 }
  78
  79 void
  80 hb_ot_layout_destroy (hb_ot_layout_t *layout)
  81 {
  82   free (layout);
  83 }
  84
  85 /*
  86  * GDEF
  87  */
  88
  89 /* TODO the public class_t is a mess */
  90
  91 hb_bool_t
  92 hb_ot_layout_has_font_glyph_classes (hb_ot_layout_t *layout)
  93 {
  94   return layout->gdef->has_glyph_classes ();
  95 }
  96
  97 HB_OT_LAYOUT_INTERNAL hb_bool_t
  98 _hb_ot_layout_has_new_glyph_classes (hb_ot_layout_t *layout)
  99 {
 100   return layout->new_gdef.len > 0;
 101 }
 102
 103 HB_OT_LAYOUT_INTERNAL unsigned int
 104 _hb_ot_layout_get_glyph_property (hb_ot_layout_t *layout,
 105                                   hb_codepoint_t  glyph)
 106 {
 107   hb_ot_layout_class_t klass;
 108
 109   /* TODO old harfbuzz doesn't always parse mark attachments as it says it was
 110    * introduced without a version bump, so it may not be safe */
 111   klass = layout->gdef->get_mark_attachment_type (glyph);
 112   if (klass)
 113     return klass << 8;
 114
 115   klass = layout->gdef->get_glyph_class (glyph);
 116
 117   if (!klass && glyph < layout->new_gdef.len)
 118     klass = layout->new_gdef.klasses[glyph];
 119
 120   switch (klass) {
 121   default:
 122   case GDEF::UnclassifiedGlyph: return HB_OT_LAYOUT_GLYPH_CLASS_UNCLASSIFIED;
 123   case GDEF::BaseGlyph:         return HB_OT_LAYOUT_GLYPH_CLASS_BASE_GLYPH;
 124   case GDEF::LigatureGlyph:     return HB_OT_LAYOUT_GLYPH_CLASS_LIGATURE;
 125   case GDEF::MarkGlyph:         return HB_OT_LAYOUT_GLYPH_CLASS_MARK;
 126   case GDEF::ComponentGlyph:    return HB_OT_LAYOUT_GLYPH_CLASS_COMPONENT;
 127   }
 128 }
 129
 130 HB_OT_LAYOUT_INTERNAL hb_bool_t
 131 _hb_ot_layout_check_glyph_property (hb_ot_layout_t *layout,
 132                                     HB_GlyphItem    gitem,
 133                                     unsigned int    lookup_flags,
 134                                     unsigned int   *property)
 135 {
 136   hb_ot_layout_glyph_class_t basic_glyph_class;
 137   unsigned int desired_attachment_class;
 138
 139   if (gitem->gproperty == HB_BUFFER_GLYPH_PROPERTIES_UNKNOWN)
 140   {
 141     gitem->gproperty = *property = _hb_ot_layout_get_glyph_property (layout, gitem->gindex);
 142     if (gitem->gproperty == HB_OT_LAYOUT_GLYPH_CLASS_UNCLASSIFIED)
 143       return false;
 144   }
 145
 146   *property = gitem->gproperty;
 147
 148   /* If the glyph was found in the MarkAttachmentClass table,
 149    * then that class value is the high byte of the result,
 150    * otherwise the low byte contains the basic type of the glyph
 151    * as defined by the GlyphClassDef table.
 152    */
 153   if (*property & LookupFlag::MarkAttachmentType)
 154     basic_glyph_class = HB_OT_LAYOUT_GLYPH_CLASS_MARK;
 155   else
 156     basic_glyph_class = (hb_ot_layout_glyph_class_t) *property;
 157
 158   /* Not covered, if, for example, basic_glyph_class
 159    * is HB_GDEF_LIGATURE and lookup_flags includes LookupFlags::IgnoreLigatures
 160    */
 161   if (lookup_flags & basic_glyph_class)
 162     return false;
 163
 164   /* The high byte of lookup_flags has the meaning
 165    * "ignore marks of attachment type different than
 166    * the attachment type specified."
 167    */
 168   desired_attachment_class = lookup_flags & LookupFlag::MarkAttachmentType;
 169   if (desired_attachment_class)
 170   {
 171     if (basic_glyph_class == HB_OT_LAYOUT_GLYPH_CLASS_MARK &&
 172         *property != desired_attachment_class)
 173       return false;
 174   }
 175
 176   return true;
 177 }
 178
 179 HB_OT_LAYOUT_INTERNAL void
 180 _hb_ot_layout_set_glyph_property (hb_ot_layout_t *layout,
 181                                   hb_codepoint_t  glyph,
 182                                   unsigned int    property)
 183 {
 184   hb_ot_layout_glyph_class_t klass;
 185
 186   if (property & LookupFlag::MarkAttachmentType)
 187     klass = HB_OT_LAYOUT_GLYPH_CLASS_MARK;
 188   else
 189     klass = (hb_ot_layout_glyph_class_t) property;
 190
 191   hb_ot_layout_set_glyph_class (layout, glyph, klass);
 192 }
 193
 194
 195 hb_ot_layout_glyph_class_t
 196 hb_ot_layout_get_glyph_class (hb_ot_layout_t *layout,
 197                               hb_codepoint_t  glyph)
 198 {
 199   unsigned int property;
 200   hb_ot_layout_class_t klass;
 201
 202   property = _hb_ot_layout_get_glyph_property (layout, glyph);
 203
 204   if (property & LookupFlag::MarkAttachmentType)
 205     return HB_OT_LAYOUT_GLYPH_CLASS_MARK;
 206
 207   return (hb_ot_layout_glyph_class_t) property;
 208 }
 209
 210 void
 211 hb_ot_layout_set_glyph_class (hb_ot_layout_t             *layout,
 212                               hb_codepoint_t              glyph,
 213                               hb_ot_layout_glyph_class_t  klass)
 214 {
 215   /* TODO optimize this, similar to old harfbuzz code for example */
 216
 217   hb_ot_layout_class_t gdef_klass;
 218   int len = layout->new_gdef.len;
 219
 220   if (HB_UNLIKELY (glyph > 65535))
 221     return;
 222
 223   if (glyph >= len) {
 224     int new_len;
 225     unsigned char *new_klasses;
 226
 227     new_len = len == 0 ? 120 : 2 * len;
 228     if (new_len > 65535)
 229       new_len = 65535;
 230     new_klasses = (unsigned char *) realloc (layout->new_gdef.klasses, new_len * sizeof (unsigned char));
 231
 232     if (HB_UNLIKELY (!new_klasses))
 233       return;
 234
 235     memset (new_klasses + len, 0, new_len - len);
 236
 237     layout->new_gdef.klasses = new_klasses;
 238     layout->new_gdef.len = new_len;
 239   }
 240
 241   switch (klass) {
 242   default:
 243   case HB_OT_LAYOUT_GLYPH_CLASS_UNCLASSIFIED:   gdef_klass = GDEF::UnclassifiedGlyph;   break;
 244   case HB_OT_LAYOUT_GLYPH_CLASS_BASE_GLYPH:     gdef_klass = GDEF::BaseGlyph;           break;
 245   case HB_OT_LAYOUT_GLYPH_CLASS_LIGATURE:       gdef_klass = GDEF::LigatureGlyph;       break;
 246   case HB_OT_LAYOUT_GLYPH_CLASS_MARK:           gdef_klass = GDEF::MarkGlyph;           break;
 247   case HB_OT_LAYOUT_GLYPH_CLASS_COMPONENT:      gdef_klass = GDEF::ComponentGlyph;      break;
 248   }
 249
 250   layout->new_gdef.klasses[glyph] = gdef_klass;
 251   return;
 252 }
 253
 254 void
 255 hb_ot_layout_build_glyph_classes (hb_ot_layout_t *layout,
 256                                   uint16_t        num_total_glyphs,
 257                                   hb_codepoint_t *glyphs,
 258                                   unsigned char  *klasses,
 259                                   uint16_t        count)
 260 {
 261   if (HB_UNLIKELY (!count || !glyphs || !klasses))
 262     return;
 263
 264   if (layout->new_gdef.len == 0) {
 265     layout->new_gdef.klasses = (unsigned char *) calloc (num_total_glyphs, sizeof (unsigned char));
 266     layout->new_gdef.len = count;
 267   }
 268
 269   for (unsigned int i = 0; i < count; i++)
 270     hb_ot_layout_set_glyph_class (layout, glyphs[i], (hb_ot_layout_glyph_class_t) klasses[i]);
 271 }
 272
 273 /*
 274  * GSUB/GPOS
 275  */
 276
 277 static const GSUBGPOS&
 278 get_gsubgpos_table (hb_ot_layout_t            *layout,
 279                     hb_ot_layout_table_type_t  table_type)
 280 {
 281   switch (table_type) {
 282     case HB_OT_LAYOUT_TABLE_TYPE_GSUB: return *(layout->gsub);
 283     case HB_OT_LAYOUT_TABLE_TYPE_GPOS: return *(layout->gpos);
 284     default:                           return Null(GSUBGPOS);
 285   }
 286 }
 287
 288
 289 unsigned int
 290 hb_ot_layout_table_get_script_count (hb_ot_layout_t            *layout,
 291                                      hb_ot_layout_table_type_t  table_type)
 292 {
 293   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 294
 295   return g.get_script_count ();
 296 }
 297
 298 hb_tag_t
 299 hb_ot_layout_table_get_script_tag (hb_ot_layout_t            *layout,
 300                                    hb_ot_layout_table_type_t  table_type,
 301                                    unsigned int               script_index)
 302 {
 303   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 304
 305   return g.get_script_tag (script_index);
 306 }
 307
 308 hb_bool_t
 309 hb_ot_layout_table_find_script (hb_ot_layout_t            *layout,
 310                                 hb_ot_layout_table_type_t  table_type,
 311                                 hb_tag_t                   script_tag,
 312                                 unsigned int              *script_index)
 313 {
 314   ASSERT_STATIC (NO_INDEX == HB_OT_LAYOUT_NO_SCRIPT_INDEX);
 315   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 316
 317   if (g.find_script_index (script_tag, script_index))
 318     return TRUE;
 319
 320   /* try finding 'DFLT' */
 321   if (g.find_script_index (HB_OT_LAYOUT_TAG_DEFAULT_SCRIPT, script_index))
 322     return FALSE;
 323
 324   /* try with 'dflt'; MS site has had typos and many fonts use it now :( */
 325   if (g.find_script_index (HB_OT_LAYOUT_TAG_DEFAULT_LANGUAGE, script_index))
 326     return FALSE;
 327
 328   if (script_index) *script_index = HB_OT_LAYOUT_NO_SCRIPT_INDEX;
 329   return FALSE;
 330 }
 331
 332 unsigned int
 333 hb_ot_layout_table_get_feature_count (hb_ot_layout_t            *layout,
 334                                       hb_ot_layout_table_type_t  table_type)
 335 {
 336   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 337
 338   return g.get_feature_count ();
 339 }
 340
 341 hb_tag_t
 342 hb_ot_layout_table_get_feature_tag (hb_ot_layout_t            *layout,
 343                                     hb_ot_layout_table_type_t  table_type,
 344                                     unsigned int               feature_index)
 345 {
 346   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 347
 348   return g.get_feature_tag (feature_index);
 349 }
 350
 351 hb_bool_t
 352 hb_ot_layout_table_find_feature (hb_ot_layout_t            *layout,
 353                                  hb_ot_layout_table_type_t  table_type,
 354                                  hb_tag_t                   feature_tag,
 355                                  unsigned int              *feature_index)
 356 {
 357   ASSERT_STATIC (NO_INDEX == HB_OT_LAYOUT_NO_FEATURE_INDEX);
 358   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 359
 360   if (g.find_feature_index (feature_tag, feature_index))
 361     return TRUE;
 362
 363   if (feature_index) *feature_index = HB_OT_LAYOUT_NO_FEATURE_INDEX;
 364   return FALSE;
 365 }
 366
 367 unsigned int
 368 hb_ot_layout_table_get_lookup_count (hb_ot_layout_t            *layout,
 369                                      hb_ot_layout_table_type_t  table_type)
 370 {
 371   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 372
 373   return g.get_lookup_count ();
 374 }
 375
 376
 377 unsigned int
 378 hb_ot_layout_script_get_language_count (hb_ot_layout_t            *layout,
 379                                         hb_ot_layout_table_type_t  table_type,
 380                                         unsigned int               script_index)
 381 {
 382   const Script &s = get_gsubgpos_table (layout, table_type).get_script (script_index);
 383
 384   return s.get_lang_sys_count ();
 385 }
 386
 387 hb_tag_t
 388 hb_ot_layout_script_get_language_tag (hb_ot_layout_t            *layout,
 389                                       hb_ot_layout_table_type_t  table_type,
 390                                       unsigned int               script_index,
 391                                       unsigned int               language_index)
 392 {
 393   const Script &s = get_gsubgpos_table (layout, table_type).get_script (script_index);
 394
 395   return s.get_lang_sys_tag (language_index);
 396 }
 397
 398 hb_bool_t
 399 hb_ot_layout_script_find_language (hb_ot_layout_t            *layout,
 400                                    hb_ot_layout_table_type_t  table_type,
 401                                    unsigned int               script_index,
 402                                    hb_tag_t                   language_tag,
 403                                    unsigned int              *language_index)
 404 {
 405   ASSERT_STATIC (NO_INDEX == HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX);
 406   const Script &s = get_gsubgpos_table (layout, table_type).get_script (script_index);
 407
 408   if (s.find_lang_sys_index (language_tag, language_index))
 409     return TRUE;
 410
 411   /* try with 'dflt'; MS site has had typos and many fonts use it now :( */
 412   if (s.find_lang_sys_index (HB_OT_LAYOUT_TAG_DEFAULT_LANGUAGE, language_index))
 413     return FALSE;
 414
 415   if (language_index) *language_index = HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX;
 416   return FALSE;
 417 }
 418
 419 hb_bool_t
 420 hb_ot_layout_language_get_required_feature_index (hb_ot_layout_t            *layout,
 421                                                   hb_ot_layout_table_type_t  table_type,
 422                                                   unsigned int               script_index,
 423                                                   unsigned int               language_index,
 424                                                   unsigned int              *feature_index)
 425 {
 426   const LangSys &l = get_gsubgpos_table (layout, table_type).get_script (script_index).get_lang_sys (language_index);
 427
 428   if (feature_index) *feature_index = l.get_required_feature_index ();
 429
 430   return l.has_required_feature ();
 431 }
 432
 433 unsigned int
 434 hb_ot_layout_language_get_feature_count (hb_ot_layout_t            *layout,
 435                                          hb_ot_layout_table_type_t  table_type,
 436                                          unsigned int               script_index,
 437                                          unsigned int               language_index)
 438 {
 439   const LangSys &l = get_gsubgpos_table (layout, table_type).get_script (script_index).get_lang_sys (language_index);
 440
 441   return l.get_feature_count ();
 442 }
 443
 444 unsigned int
 445 hb_ot_layout_language_get_feature_index (hb_ot_layout_t            *layout,
 446                                          hb_ot_layout_table_type_t  table_type,
 447                                          unsigned int               script_index,
 448                                          unsigned int               language_index,
 449                                          unsigned int               num_feature)
 450 {
 451   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 452   const LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
 453
 454   return l.get_feature_index (num_feature);
 455 }
 456
 457 hb_tag_t
 458 hb_ot_layout_language_get_feature_tag (hb_ot_layout_t            *layout,
 459                                        hb_ot_layout_table_type_t  table_type,
 460                                        unsigned int               script_index,
 461                                        unsigned int               language_index,
 462                                        unsigned int               num_feature)
 463 {
 464   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 465   const LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
 466   unsigned int feature_index = l.get_feature_index (num_feature);
 467
 468   return g.get_feature_tag (feature_index);
 469 }
 470
 471
 472 hb_bool_t
 473 hb_ot_layout_language_find_feature (hb_ot_layout_t            *layout,
 474                                     hb_ot_layout_table_type_t  table_type,
 475                                     unsigned int               script_index,
 476                                     unsigned int               language_index,
 477                                     hb_tag_t                   feature_tag,
 478                                     unsigned int              *feature_index)
 479 {
 480   ASSERT_STATIC (NO_INDEX == HB_OT_LAYOUT_NO_FEATURE_INDEX);
 481   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 482   const LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
 483
 484   unsigned int num_features = l.get_feature_count ();
 485   for (unsigned int i = 0; i < num_features; i++) {
 486     unsigned int f_index = l.get_feature_index (i);
 487
 488     if (feature_tag == g.get_feature_tag (f_index)) {
 489       if (feature_index) *feature_index = f_index;
 490       return TRUE;
 491     }
 492   }
 493
 494   if (feature_index) *feature_index = HB_OT_LAYOUT_NO_FEATURE_INDEX;
 495   return FALSE;
 496 }
 497
 498 unsigned int
 499 hb_ot_layout_feature_get_lookup_count (hb_ot_layout_t            *layout,
 500                                        hb_ot_layout_table_type_t  table_type,
 501                                        unsigned int               feature_index)
 502 {
 503   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 504   const Feature &f = g.get_feature (feature_index);
 505
 506   return f.get_lookup_count ();
 507 }
 508
 509 unsigned int
 510 hb_ot_layout_feature_get_lookup_index (hb_ot_layout_t            *layout,
 511                                        hb_ot_layout_table_type_t  table_type,
 512                                        unsigned int               feature_index,
 513                                        unsigned int               num_lookup)
 514 {
 515   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 516   const Feature &f = g.get_feature (feature_index);
 517
 518   return f.get_lookup_index (num_lookup);
 519 }
 520
 521 /*
 522  * GSUB
 523  */
 524
 525 hb_bool_t
 526 hb_ot_layout_substitute_lookup (hb_ot_layout_t              *layout,
 527                                 hb_buffer_t                 *buffer,
 528                                 unsigned int                 lookup_index,
 529                                 hb_ot_layout_feature_mask_t  mask)
 530 {
 531   return layout->gsub->substitute_lookup (layout, buffer, lookup_index, mask);
 532 }
 533
 534 /*
 535  * GPOS
 536  */
 537
 538 hb_bool_t
 539 hb_ot_layout_position_lookup   (hb_ot_layout_t              *layout,
 540                                 hb_buffer_t                 *buffer,
 541                                 unsigned int                 lookup_index,
 542                                 hb_ot_layout_feature_mask_t  mask)
 543 {
 544   return layout->gpos->position_lookup (layout, buffer, lookup_index, mask);
 545 }
 546
 547
 548
 549 /* TODO dupped, until he old code can be removed */
 550
 551 static HB_Error
 552 hb_buffer_duplicate_out_buffer( HB_Buffer buffer )
 553 {
 554   if ( !buffer->alt_string )
 555     {
 556       HB_Error error;
 557
 558       if ( ALLOC_ARRAY( buffer->alt_string, buffer->allocated, HB_GlyphItemRec ) )
 559         return error;
 560     }
 561
 562   buffer->out_string = buffer->alt_string;
 563   memcpy( buffer->out_string, buffer->in_string, buffer->out_length * sizeof (buffer->out_string[0]) );
 564   buffer->separate_out = TRUE;
 565
 566   return HB_Err_Ok;
 567 }
 568
 569
 570
 571 HB_INTERNAL HB_Error
 572 _hb_buffer_add_output_glyph_ids( HB_Buffer  buffer,
 573                               HB_UShort  num_in,
 574                               HB_UShort  num_out,
 575                               const GlyphID *glyph_data,
 576                               HB_UShort  component,
 577                               HB_UShort  ligID )
 578 {
 579   HB_Error  error;
 580   HB_UShort i;
 581   HB_UInt properties;
 582   HB_UInt cluster;
 583
 584   error = hb_buffer_ensure( buffer, buffer->out_pos + num_out );
 585   if ( error )
 586     return error;
 587
 588   if ( !buffer->separate_out )
 589     {
 590       error = hb_buffer_duplicate_out_buffer( buffer );
 591       if ( error )
 592         return error;
 593     }
 594
 595   properties = buffer->in_string[buffer->in_pos].properties;
 596   cluster = buffer->in_string[buffer->in_pos].cluster;
 597   if ( component == 0xFFFF )
 598     component = buffer->in_string[buffer->in_pos].component;
 599   if ( ligID == 0xFFFF )
 600     ligID = buffer->in_string[buffer->in_pos].ligID;
 601
 602   for ( i = 0; i < num_out; i++ )
 603   {
 604     HB_GlyphItem item = &buffer->out_string[buffer->out_pos + i];
 605
 606     item->gindex = glyph_data[i];
 607     item->properties = properties;
 608     item->cluster = cluster;
 609     item->component = component;
 610     item->ligID = ligID;
 611     item->gproperty = HB_GLYPH_PROPERTY_UNKNOWN;
 612   }
 613
 614   buffer->in_pos  += num_in;
 615   buffer->out_pos += num_out;
 616
 617   buffer->out_length = buffer->out_pos;
 618
 619   return HB_Err_Ok;
 620 }
 621