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 void
  86 hb_ot_layout_set_direction (hb_ot_layout_t *layout,
  87                             hb_bool_t r2l)
  88 {
  89   layout->gpos_info.r2l = !!r2l;
  90 }
  91
  92 void
  93 hb_ot_layout_set_hinting (hb_ot_layout_t *layout,
  94                           hb_bool_t hinted)
  95 {
  96   layout->gpos_info.dvi = !hinted;
  97 }
  98
  99 void
 100 hb_ot_layout_set_scale (hb_ot_layout_t *layout,
 101                         hb_16dot16_t x_scale, hb_16dot16_t y_scale)
 102 {
 103   layout->gpos_info.x_scale = x_scale;
 104   layout->gpos_info.y_scale = y_scale;
 105 }
 106
 107 void
 108 hb_ot_layout_set_ppem (hb_ot_layout_t *layout,
 109                        unsigned int x_ppem, unsigned int y_ppem)
 110 {
 111   layout->gpos_info.x_ppem = x_ppem;
 112   layout->gpos_info.y_ppem = y_ppem;
 113 }
 114
 115
 116 /*
 117  * GDEF
 118  */
 119
 120 /* TODO the public class_t is a mess */
 121
 122 hb_bool_t
 123 hb_ot_layout_has_font_glyph_classes (hb_ot_layout_t *layout)
 124 {
 125   return layout->gdef->has_glyph_classes ();
 126 }
 127
 128 HB_OT_LAYOUT_INTERNAL hb_bool_t
 129 _hb_ot_layout_has_new_glyph_classes (hb_ot_layout_t *layout)
 130 {
 131   return layout->new_gdef.len > 0;
 132 }
 133
 134 HB_OT_LAYOUT_INTERNAL unsigned int
 135 _hb_ot_layout_get_glyph_property (hb_ot_layout_t *layout,
 136                                   hb_codepoint_t  glyph)
 137 {
 138   hb_ot_layout_class_t klass;
 139
 140   /* TODO old harfbuzz doesn't always parse mark attachments as it says it was
 141    * introduced without a version bump, so it may not be safe */
 142   klass = layout->gdef->get_mark_attachment_type (glyph);
 143   if (klass)
 144     return klass << 8;
 145
 146   klass = layout->gdef->get_glyph_class (glyph);
 147
 148   if (!klass && glyph < layout->new_gdef.len)
 149     klass = layout->new_gdef.klasses[glyph];
 150
 151   switch (klass) {
 152   default:
 153   case GDEF::UnclassifiedGlyph: return HB_OT_LAYOUT_GLYPH_CLASS_UNCLASSIFIED;
 154   case GDEF::BaseGlyph:         return HB_OT_LAYOUT_GLYPH_CLASS_BASE_GLYPH;
 155   case GDEF::LigatureGlyph:     return HB_OT_LAYOUT_GLYPH_CLASS_LIGATURE;
 156   case GDEF::MarkGlyph:         return HB_OT_LAYOUT_GLYPH_CLASS_MARK;
 157   case GDEF::ComponentGlyph:    return HB_OT_LAYOUT_GLYPH_CLASS_COMPONENT;
 158   }
 159 }
 160
 161 HB_OT_LAYOUT_INTERNAL hb_bool_t
 162 _hb_ot_layout_check_glyph_property (hb_ot_layout_t *layout,
 163                                     HB_GlyphItem    gitem,
 164                                     unsigned int    lookup_flags,
 165                                     unsigned int   *property)
 166 {
 167   hb_ot_layout_glyph_class_t basic_glyph_class;
 168   unsigned int desired_attachment_class;
 169
 170   if (gitem->gproperty == HB_BUFFER_GLYPH_PROPERTIES_UNKNOWN)
 171   {
 172     gitem->gproperty = *property = _hb_ot_layout_get_glyph_property (layout, gitem->gindex);
 173     if (gitem->gproperty == HB_OT_LAYOUT_GLYPH_CLASS_UNCLASSIFIED)
 174       return false;
 175   }
 176
 177   *property = gitem->gproperty;
 178
 179   /* If the glyph was found in the MarkAttachmentClass table,
 180    * then that class value is the high byte of the result,
 181    * otherwise the low byte contains the basic type of the glyph
 182    * as defined by the GlyphClassDef table.
 183    */
 184   if (*property & LookupFlag::MarkAttachmentType)
 185     basic_glyph_class = HB_OT_LAYOUT_GLYPH_CLASS_MARK;
 186   else
 187     basic_glyph_class = (hb_ot_layout_glyph_class_t) *property;
 188
 189   /* Not covered, if, for example, basic_glyph_class
 190    * is HB_GDEF_LIGATURE and lookup_flags includes LookupFlags::IgnoreLigatures
 191    */
 192   if (lookup_flags & basic_glyph_class)
 193     return false;
 194
 195   /* The high byte of lookup_flags has the meaning
 196    * "ignore marks of attachment type different than
 197    * the attachment type specified."
 198    */
 199   desired_attachment_class = lookup_flags & LookupFlag::MarkAttachmentType;
 200   if (desired_attachment_class)
 201   {
 202     if (basic_glyph_class == HB_OT_LAYOUT_GLYPH_CLASS_MARK &&
 203         *property != desired_attachment_class)
 204       return false;
 205   }
 206
 207   return true;
 208 }
 209
 210 HB_OT_LAYOUT_INTERNAL void
 211 _hb_ot_layout_set_glyph_property (hb_ot_layout_t *layout,
 212                                   hb_codepoint_t  glyph,
 213                                   unsigned int    property)
 214 {
 215   hb_ot_layout_glyph_class_t klass;
 216
 217   if (property & LookupFlag::MarkAttachmentType)
 218     klass = HB_OT_LAYOUT_GLYPH_CLASS_MARK;
 219   else
 220     klass = (hb_ot_layout_glyph_class_t) property;
 221
 222   hb_ot_layout_set_glyph_class (layout, glyph, klass);
 223 }
 224
 225
 226 hb_ot_layout_glyph_class_t
 227 hb_ot_layout_get_glyph_class (hb_ot_layout_t *layout,
 228                               hb_codepoint_t  glyph)
 229 {
 230   unsigned int property;
 231   hb_ot_layout_class_t klass;
 232
 233   property = _hb_ot_layout_get_glyph_property (layout, glyph);
 234
 235   if (property & LookupFlag::MarkAttachmentType)
 236     return HB_OT_LAYOUT_GLYPH_CLASS_MARK;
 237
 238   return (hb_ot_layout_glyph_class_t) property;
 239 }
 240
 241 void
 242 hb_ot_layout_set_glyph_class (hb_ot_layout_t             *layout,
 243                               hb_codepoint_t              glyph,
 244                               hb_ot_layout_glyph_class_t  klass)
 245 {
 246   /* TODO optimize this, similar to old harfbuzz code for example */
 247
 248   hb_ot_layout_class_t gdef_klass;
 249   int len = layout->new_gdef.len;
 250
 251   if (HB_UNLIKELY (glyph > 65535))
 252     return;
 253
 254   if (glyph >= len) {
 255     int new_len;
 256     unsigned char *new_klasses;
 257
 258     new_len = len == 0 ? 120 : 2 * len;
 259     if (new_len > 65535)
 260       new_len = 65535;
 261     new_klasses = (unsigned char *) realloc (layout->new_gdef.klasses, new_len * sizeof (unsigned char));
 262
 263     if (HB_UNLIKELY (!new_klasses))
 264       return;
 265
 266     memset (new_klasses + len, 0, new_len - len);
 267
 268     layout->new_gdef.klasses = new_klasses;
 269     layout->new_gdef.len = new_len;
 270   }
 271
 272   switch (klass) {
 273   default:
 274   case HB_OT_LAYOUT_GLYPH_CLASS_UNCLASSIFIED:   gdef_klass = GDEF::UnclassifiedGlyph;   break;
 275   case HB_OT_LAYOUT_GLYPH_CLASS_BASE_GLYPH:     gdef_klass = GDEF::BaseGlyph;           break;
 276   case HB_OT_LAYOUT_GLYPH_CLASS_LIGATURE:       gdef_klass = GDEF::LigatureGlyph;       break;
 277   case HB_OT_LAYOUT_GLYPH_CLASS_MARK:           gdef_klass = GDEF::MarkGlyph;           break;
 278   case HB_OT_LAYOUT_GLYPH_CLASS_COMPONENT:      gdef_klass = GDEF::ComponentGlyph;      break;
 279   }
 280
 281   layout->new_gdef.klasses[glyph] = gdef_klass;
 282   return;
 283 }
 284
 285 void
 286 hb_ot_layout_build_glyph_classes (hb_ot_layout_t *layout,
 287                                   uint16_t        num_total_glyphs,
 288                                   hb_codepoint_t *glyphs,
 289                                   unsigned char  *klasses,
 290                                   uint16_t        count)
 291 {
 292   if (HB_UNLIKELY (!count || !glyphs || !klasses))
 293     return;
 294
 295   if (layout->new_gdef.len == 0) {
 296     layout->new_gdef.klasses = (unsigned char *) calloc (num_total_glyphs, sizeof (unsigned char));
 297     layout->new_gdef.len = count;
 298   }
 299
 300   for (unsigned int i = 0; i < count; i++)
 301     hb_ot_layout_set_glyph_class (layout, glyphs[i], (hb_ot_layout_glyph_class_t) klasses[i]);
 302 }
 303
 304 /*
 305  * GSUB/GPOS
 306  */
 307
 308 static const GSUBGPOS&
 309 get_gsubgpos_table (hb_ot_layout_t            *layout,
 310                     hb_ot_layout_table_type_t  table_type)
 311 {
 312   switch (table_type) {
 313     case HB_OT_LAYOUT_TABLE_TYPE_GSUB: return *(layout->gsub);
 314     case HB_OT_LAYOUT_TABLE_TYPE_GPOS: return *(layout->gpos);
 315     default:                           return Null(GSUBGPOS);
 316   }
 317 }
 318
 319
 320 unsigned int
 321 hb_ot_layout_table_get_script_count (hb_ot_layout_t            *layout,
 322                                      hb_ot_layout_table_type_t  table_type)
 323 {
 324   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 325
 326   return g.get_script_count ();
 327 }
 328
 329 hb_tag_t
 330 hb_ot_layout_table_get_script_tag (hb_ot_layout_t            *layout,
 331                                    hb_ot_layout_table_type_t  table_type,
 332                                    unsigned int               script_index)
 333 {
 334   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 335
 336   return g.get_script_tag (script_index);
 337 }
 338
 339 hb_bool_t
 340 hb_ot_layout_table_find_script (hb_ot_layout_t            *layout,
 341                                 hb_ot_layout_table_type_t  table_type,
 342                                 hb_tag_t                   script_tag,
 343                                 unsigned int              *script_index)
 344 {
 345   ASSERT_STATIC (NO_INDEX == HB_OT_LAYOUT_NO_SCRIPT_INDEX);
 346   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 347
 348   if (g.find_script_index (script_tag, script_index))
 349     return TRUE;
 350
 351   /* try finding 'DFLT' */
 352   if (g.find_script_index (HB_OT_LAYOUT_TAG_DEFAULT_SCRIPT, script_index))
 353     return FALSE;
 354
 355   /* try with 'dflt'; MS site has had typos and many fonts use it now :( */
 356   if (g.find_script_index (HB_OT_LAYOUT_TAG_DEFAULT_LANGUAGE, script_index))
 357     return FALSE;
 358
 359   if (script_index) *script_index = HB_OT_LAYOUT_NO_SCRIPT_INDEX;
 360   return FALSE;
 361 }
 362
 363 unsigned int
 364 hb_ot_layout_table_get_feature_count (hb_ot_layout_t            *layout,
 365                                       hb_ot_layout_table_type_t  table_type)
 366 {
 367   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 368
 369   return g.get_feature_count ();
 370 }
 371
 372 hb_tag_t
 373 hb_ot_layout_table_get_feature_tag (hb_ot_layout_t            *layout,
 374                                     hb_ot_layout_table_type_t  table_type,
 375                                     unsigned int               feature_index)
 376 {
 377   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 378
 379   return g.get_feature_tag (feature_index);
 380 }
 381
 382 hb_bool_t
 383 hb_ot_layout_table_find_feature (hb_ot_layout_t            *layout,
 384                                  hb_ot_layout_table_type_t  table_type,
 385                                  hb_tag_t                   feature_tag,
 386                                  unsigned int              *feature_index)
 387 {
 388   ASSERT_STATIC (NO_INDEX == HB_OT_LAYOUT_NO_FEATURE_INDEX);
 389   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 390
 391   if (g.find_feature_index (feature_tag, feature_index))
 392     return TRUE;
 393
 394   if (feature_index) *feature_index = HB_OT_LAYOUT_NO_FEATURE_INDEX;
 395   return FALSE;
 396 }
 397
 398 unsigned int
 399 hb_ot_layout_table_get_lookup_count (hb_ot_layout_t            *layout,
 400                                      hb_ot_layout_table_type_t  table_type)
 401 {
 402   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 403
 404   return g.get_lookup_count ();
 405 }
 406
 407
 408 unsigned int
 409 hb_ot_layout_script_get_language_count (hb_ot_layout_t            *layout,
 410                                         hb_ot_layout_table_type_t  table_type,
 411                                         unsigned int               script_index)
 412 {
 413   const Script &s = get_gsubgpos_table (layout, table_type).get_script (script_index);
 414
 415   return s.get_lang_sys_count ();
 416 }
 417
 418 hb_tag_t
 419 hb_ot_layout_script_get_language_tag (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 {
 424   const Script &s = get_gsubgpos_table (layout, table_type).get_script (script_index);
 425
 426   return s.get_lang_sys_tag (language_index);
 427 }
 428
 429 hb_bool_t
 430 hb_ot_layout_script_find_language (hb_ot_layout_t            *layout,
 431                                    hb_ot_layout_table_type_t  table_type,
 432                                    unsigned int               script_index,
 433                                    hb_tag_t                   language_tag,
 434                                    unsigned int              *language_index)
 435 {
 436   ASSERT_STATIC (NO_INDEX == HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX);
 437   const Script &s = get_gsubgpos_table (layout, table_type).get_script (script_index);
 438
 439   if (s.find_lang_sys_index (language_tag, language_index))
 440     return TRUE;
 441
 442   /* try with 'dflt'; MS site has had typos and many fonts use it now :( */
 443   if (s.find_lang_sys_index (HB_OT_LAYOUT_TAG_DEFAULT_LANGUAGE, language_index))
 444     return FALSE;
 445
 446   if (language_index) *language_index = HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX;
 447   return FALSE;
 448 }
 449
 450 hb_bool_t
 451 hb_ot_layout_language_get_required_feature_index (hb_ot_layout_t            *layout,
 452                                                   hb_ot_layout_table_type_t  table_type,
 453                                                   unsigned int               script_index,
 454                                                   unsigned int               language_index,
 455                                                   unsigned int              *feature_index)
 456 {
 457   const LangSys &l = get_gsubgpos_table (layout, table_type).get_script (script_index).get_lang_sys (language_index);
 458
 459   if (feature_index) *feature_index = l.get_required_feature_index ();
 460
 461   return l.has_required_feature ();
 462 }
 463
 464 unsigned int
 465 hb_ot_layout_language_get_feature_count (hb_ot_layout_t            *layout,
 466                                          hb_ot_layout_table_type_t  table_type,
 467                                          unsigned int               script_index,
 468                                          unsigned int               language_index)
 469 {
 470   const LangSys &l = get_gsubgpos_table (layout, table_type).get_script (script_index).get_lang_sys (language_index);
 471
 472   return l.get_feature_count ();
 473 }
 474
 475 unsigned int
 476 hb_ot_layout_language_get_feature_index (hb_ot_layout_t            *layout,
 477                                          hb_ot_layout_table_type_t  table_type,
 478                                          unsigned int               script_index,
 479                                          unsigned int               language_index,
 480                                          unsigned int               num_feature)
 481 {
 482   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 483   const LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
 484
 485   return l.get_feature_index (num_feature);
 486 }
 487
 488 hb_tag_t
 489 hb_ot_layout_language_get_feature_tag (hb_ot_layout_t            *layout,
 490                                        hb_ot_layout_table_type_t  table_type,
 491                                        unsigned int               script_index,
 492                                        unsigned int               language_index,
 493                                        unsigned int               num_feature)
 494 {
 495   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 496   const LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
 497   unsigned int feature_index = l.get_feature_index (num_feature);
 498
 499   return g.get_feature_tag (feature_index);
 500 }
 501
 502
 503 hb_bool_t
 504 hb_ot_layout_language_find_feature (hb_ot_layout_t            *layout,
 505                                     hb_ot_layout_table_type_t  table_type,
 506                                     unsigned int               script_index,
 507                                     unsigned int               language_index,
 508                                     hb_tag_t                   feature_tag,
 509                                     unsigned int              *feature_index)
 510 {
 511   ASSERT_STATIC (NO_INDEX == HB_OT_LAYOUT_NO_FEATURE_INDEX);
 512   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 513   const LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
 514
 515   unsigned int num_features = l.get_feature_count ();
 516   for (unsigned int i = 0; i < num_features; i++) {
 517     unsigned int f_index = l.get_feature_index (i);
 518
 519     if (feature_tag == g.get_feature_tag (f_index)) {
 520       if (feature_index) *feature_index = f_index;
 521       return TRUE;
 522     }
 523   }
 524
 525   if (feature_index) *feature_index = HB_OT_LAYOUT_NO_FEATURE_INDEX;
 526   return FALSE;
 527 }
 528
 529 unsigned int
 530 hb_ot_layout_feature_get_lookup_count (hb_ot_layout_t            *layout,
 531                                        hb_ot_layout_table_type_t  table_type,
 532                                        unsigned int               feature_index)
 533 {
 534   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 535   const Feature &f = g.get_feature (feature_index);
 536
 537   return f.get_lookup_count ();
 538 }
 539
 540 unsigned int
 541 hb_ot_layout_feature_get_lookup_index (hb_ot_layout_t            *layout,
 542                                        hb_ot_layout_table_type_t  table_type,
 543                                        unsigned int               feature_index,
 544                                        unsigned int               num_lookup)
 545 {
 546   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 547   const Feature &f = g.get_feature (feature_index);
 548
 549   return f.get_lookup_index (num_lookup);
 550 }
 551
 552 /*
 553  * GSUB
 554  */
 555
 556 hb_bool_t
 557 hb_ot_layout_substitute_lookup (hb_ot_layout_t              *layout,
 558                                 hb_buffer_t                 *buffer,
 559                                 unsigned int                 lookup_index,
 560                                 hb_ot_layout_feature_mask_t  mask)
 561 {
 562   return layout->gsub->substitute_lookup (layout, buffer, lookup_index, mask);
 563 }
 564
 565 /*
 566  * GPOS
 567  */
 568
 569 hb_bool_t
 570 hb_ot_layout_position_lookup   (hb_ot_layout_t              *layout,
 571                                 hb_buffer_t                 *buffer,
 572                                 unsigned int                 lookup_index,
 573                                 hb_ot_layout_feature_mask_t  mask)
 574 {
 575   return layout->gpos->position_lookup (layout, buffer, lookup_index, mask);
 576 }
 577
 578
 579
 580 /* TODO dupped, until he old code can be removed */
 581
 582 static HB_Error
 583 hb_buffer_duplicate_out_buffer( HB_Buffer buffer )
 584 {
 585   if ( !buffer->alt_string )
 586     {
 587       HB_Error error;
 588
 589       if ( ALLOC_ARRAY( buffer->alt_string, buffer->allocated, HB_GlyphItemRec ) )
 590         return error;
 591     }
 592
 593   buffer->out_string = buffer->alt_string;
 594   memcpy( buffer->out_string, buffer->in_string, buffer->out_length * sizeof (buffer->out_string[0]) );
 595   buffer->separate_out = TRUE;
 596
 597   return HB_Err_Ok;
 598 }
 599
 600
 601
 602 HB_INTERNAL HB_Error
 603 _hb_buffer_add_output_glyph_ids( HB_Buffer  buffer,
 604                               HB_UShort  num_in,
 605                               HB_UShort  num_out,
 606                               const GlyphID *glyph_data,
 607                               HB_UShort  component,
 608                               HB_UShort  ligID )
 609 {
 610   HB_Error  error;
 611   HB_UShort i;
 612   HB_UInt properties;
 613   HB_UInt cluster;
 614
 615   error = hb_buffer_ensure( buffer, buffer->out_pos + num_out );
 616   if ( error )
 617     return error;
 618
 619   if ( !buffer->separate_out )
 620     {
 621       error = hb_buffer_duplicate_out_buffer( buffer );
 622       if ( error )
 623         return error;
 624     }
 625
 626   properties = buffer->in_string[buffer->in_pos].properties;
 627   cluster = buffer->in_string[buffer->in_pos].cluster;
 628   if ( component == 0xFFFF )
 629     component = buffer->in_string[buffer->in_pos].component;
 630   if ( ligID == 0xFFFF )
 631     ligID = buffer->in_string[buffer->in_pos].ligID;
 632
 633   for ( i = 0; i < num_out; i++ )
 634   {
 635     HB_GlyphItem item = &buffer->out_string[buffer->out_pos + i];
 636
 637     item->gindex = glyph_data[i];
 638     item->properties = properties;
 639     item->cluster = cluster;
 640     item->component = component;
 641     item->ligID = ligID;
 642     item->gproperty = HB_GLYPH_PROPERTY_UNKNOWN;
 643   }
 644
 645   buffer->in_pos  += num_in;
 646   buffer->out_pos += num_out;
 647
 648   buffer->out_length = buffer->out_pos;
 649
 650   return HB_Err_Ok;
 651 }
 652