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  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 struct _hb_ot_layout_t {
  46   const GDEF *gdef;
  47   const GSUB *gsub;
  48   const /*XXX*/GSUBGPOS *gpos;
  49
  50   struct {
  51     unsigned char *klasses;
  52     unsigned int len;
  53   } new_gdef;
  54
  55   /* TODO add max-nesting-level here? */
  56 };
  57
  58 hb_ot_layout_t *
  59 hb_ot_layout_create (void)
  60 {
  61   hb_ot_layout_t *layout = (hb_ot_layout_t *) calloc (1, sizeof (hb_ot_layout_t));
  62
  63   layout->gdef = &NullGDEF;
  64   layout->gsub = &NullGSUB;
  65   layout->gpos = &/*XXX*/NullGSUBGPOS;
  66
  67   return layout;
  68 }
  69
  70 hb_ot_layout_t *
  71 hb_ot_layout_create_for_data (const char *font_data,
  72                               int         face_index)
  73 {
  74   hb_ot_layout_t *layout;
  75
  76   if (HB_UNLIKELY (font_data == NULL))
  77     return hb_ot_layout_create ();
  78
  79   layout = (hb_ot_layout_t *) calloc (1, sizeof (hb_ot_layout_t));
  80
  81   const OpenTypeFontFile &font = OpenTypeFontFile::get_for_data (font_data);
  82   const OpenTypeFontFace &face = font.get_face (face_index);
  83
  84   layout->gdef = &GDEF::get_for_data (font.get_table_data (face.get_table_by_tag (GDEF::Tag)));
  85   layout->gsub = &GSUB::get_for_data (font.get_table_data (face.get_table_by_tag (GSUB::Tag)));
  86   layout->gpos = &/*XXX*/GSUBGPOS::get_for_data (font.get_table_data (face.get_table_by_tag (/*XXX*/GSUBGPOS::GPOSTag)));
  87
  88   return layout;
  89 }
  90
  91 void
  92 hb_ot_layout_destroy (hb_ot_layout_t *layout)
  93 {
  94   free (layout);
  95 }
  96
  97 /*
  98  * GDEF
  99  */
 100
 101 hb_bool_t
 102 hb_ot_layout_has_font_glyph_classes (hb_ot_layout_t *layout)
 103 {
 104   return layout->gdef->has_glyph_classes ();
 105 }
 106
 107 HB_OT_LAYOUT_INTERNAL hb_bool_t
 108 _hb_ot_layout_has_new_glyph_classes (hb_ot_layout_t *layout)
 109 {
 110   return layout->new_gdef.len > 0;
 111 }
 112
 113 HB_OT_LAYOUT_INTERNAL hb_ot_layout_glyph_properties_t
 114 _hb_ot_layout_get_glyph_properties (hb_ot_layout_t *layout,
 115                                     hb_codepoint_t  glyph)
 116 {
 117   hb_ot_layout_class_t klass;
 118
 119   /* TODO old harfbuzz doesn't always parse mark attachments as it says it was
 120    * introduced without a version bump, so it may not be safe */
 121   klass = layout->gdef->get_mark_attachment_type (glyph);
 122   if (klass)
 123     return klass << 8;
 124
 125   klass = layout->gdef->get_glyph_class (glyph);
 126
 127   if (!klass && glyph < layout->new_gdef.len)
 128     klass = layout->new_gdef.klasses[glyph];
 129
 130   switch (klass) {
 131   default:
 132   case GDEF::UnclassifiedGlyph: return HB_OT_LAYOUT_GLYPH_CLASS_UNCLASSIFIED;
 133   case GDEF::BaseGlyph:         return HB_OT_LAYOUT_GLYPH_CLASS_BASE_GLYPH;
 134   case GDEF::LigatureGlyph:     return HB_OT_LAYOUT_GLYPH_CLASS_LIGATURE;
 135   case GDEF::MarkGlyph:         return HB_OT_LAYOUT_GLYPH_CLASS_MARK;
 136   case GDEF::ComponentGlyph:    return HB_OT_LAYOUT_GLYPH_CLASS_COMPONENT;
 137   }
 138 }
 139
 140 HB_OT_LAYOUT_INTERNAL hb_bool_t
 141 _hb_ot_layout_check_glyph_properties (hb_ot_layout_t                  *layout,
 142                                       HB_GlyphItem                     gitem,
 143                                       hb_ot_layout_lookup_flags_t      lookup_flags,
 144                                       hb_ot_layout_glyph_properties_t *property)
 145 {
 146   hb_ot_layout_glyph_class_t basic_glyph_class;
 147   hb_ot_layout_glyph_properties_t desired_attachment_class;
 148
 149   if (gitem->gproperties == HB_BUFFER_GLYPH_PROPERTIES_UNKNOWN)
 150   {
 151     gitem->gproperties = *property = _hb_ot_layout_get_glyph_properties (layout, gitem->gindex);
 152     if (gitem->gproperties == HB_OT_LAYOUT_GLYPH_CLASS_UNCLASSIFIED)
 153       return false;
 154   }
 155
 156   *property = gitem->gproperties;
 157
 158   /* If the glyph was found in the MarkAttachmentClass table,
 159    * then that class value is the high byte of the result,
 160    * otherwise the low byte contains the basic type of the glyph
 161    * as defined by the GlyphClassDef table.
 162    */
 163   if (*property & LookupFlag::MarkAttachmentType)
 164     basic_glyph_class = HB_OT_LAYOUT_GLYPH_CLASS_MARK;
 165   else
 166     basic_glyph_class = (hb_ot_layout_glyph_class_t) *property;
 167
 168   /* Not covered, if, for example, basic_glyph_class
 169    * is HB_GDEF_LIGATURE and lookup_flags includes LookupFlags::IgnoreLigatures
 170    */
 171   if (lookup_flags & basic_glyph_class)
 172     return false;
 173
 174   /* The high byte of lookup_flags has the meaning
 175    * "ignore marks of attachment type different than
 176    * the attachment type specified."
 177    */
 178   desired_attachment_class = lookup_flags & LookupFlag::MarkAttachmentType;
 179   if (desired_attachment_class)
 180   {
 181     if (basic_glyph_class == HB_OT_LAYOUT_GLYPH_CLASS_MARK &&
 182         *property != desired_attachment_class )
 183       return false;
 184   }
 185
 186   return true;
 187 }
 188
 189
 190 hb_ot_layout_glyph_class_t
 191 hb_ot_layout_get_glyph_class (hb_ot_layout_t *layout,
 192                               hb_codepoint_t  glyph)
 193 {
 194   hb_ot_layout_glyph_properties_t properties;
 195   hb_ot_layout_class_t klass;
 196
 197   properties = _hb_ot_layout_get_glyph_properties (layout, glyph);
 198
 199   if (properties & 0xFF00)
 200     return HB_OT_LAYOUT_GLYPH_CLASS_MARK;
 201
 202   return (hb_ot_layout_glyph_class_t) properties;
 203 }
 204
 205 void
 206 hb_ot_layout_set_glyph_class (hb_ot_layout_t             *layout,
 207                               hb_codepoint_t              glyph,
 208                               hb_ot_layout_glyph_class_t  klass)
 209 {
 210   /* TODO optimize this, similar to old harfbuzz code for example */
 211
 212   hb_ot_layout_class_t gdef_klass;
 213   int len = layout->new_gdef.len;
 214
 215   if (glyph >= len) {
 216     int new_len;
 217     unsigned char *new_klasses;
 218
 219     new_len = len == 0 ? 120 : 2 * len;
 220     if (new_len > 65535)
 221       new_len = 65535;
 222     new_klasses = (unsigned char *) realloc (layout->new_gdef.klasses, new_len * sizeof (unsigned char));
 223
 224     if (G_UNLIKELY (!new_klasses))
 225       return;
 226
 227     memset (new_klasses + len, 0, new_len - len);
 228
 229     layout->new_gdef.klasses = new_klasses;
 230     layout->new_gdef.len = new_len;
 231   }
 232
 233   switch (klass) {
 234   default:
 235   case HB_OT_LAYOUT_GLYPH_CLASS_UNCLASSIFIED:   gdef_klass = GDEF::UnclassifiedGlyph;   break;
 236   case HB_OT_LAYOUT_GLYPH_CLASS_BASE_GLYPH:     gdef_klass = GDEF::BaseGlyph;           break;
 237   case HB_OT_LAYOUT_GLYPH_CLASS_LIGATURE:       gdef_klass = GDEF::LigatureGlyph;       break;
 238   case HB_OT_LAYOUT_GLYPH_CLASS_MARK:           gdef_klass = GDEF::MarkGlyph;           break;
 239   case HB_OT_LAYOUT_GLYPH_CLASS_COMPONENT:      gdef_klass = GDEF::ComponentGlyph;      break;
 240   }
 241
 242   layout->new_gdef.klasses[glyph] = gdef_klass;
 243   return;
 244 }
 245
 246 void
 247 hb_ot_layout_build_glyph_classes (hb_ot_layout_t *layout,
 248                                   uint16_t        num_total_glyphs,
 249                                   hb_codepoint_t *glyphs,
 250                                   unsigned char  *klasses,
 251                                   uint16_t        count)
 252 {
 253   int i;
 254
 255   if (G_UNLIKELY (!count || !glyphs || !klasses))
 256     return;
 257
 258   if (layout->new_gdef.len == 0) {
 259     layout->new_gdef.klasses = (unsigned char *) calloc (num_total_glyphs, sizeof (unsigned char));
 260     layout->new_gdef.len = count;
 261   }
 262
 263   for (i = 0; i < count; i++)
 264     hb_ot_layout_set_glyph_class (layout, glyphs[i], (hb_ot_layout_glyph_class_t) klasses[i]);
 265 }
 266
 267 /*
 268  * GSUB/GPOS
 269  */
 270
 271 static const GSUBGPOS&
 272 get_gsubgpos_table (hb_ot_layout_t            *layout,
 273                     hb_ot_layout_table_type_t  table_type)
 274 {
 275   switch (table_type) {
 276     case HB_OT_LAYOUT_TABLE_TYPE_GSUB: return *(layout->gsub);
 277     case HB_OT_LAYOUT_TABLE_TYPE_GPOS: return *(layout->gpos);
 278     default:                           return NullGSUBGPOS;
 279   }
 280 }
 281
 282
 283 unsigned int
 284 hb_ot_layout_table_get_script_count (hb_ot_layout_t            *layout,
 285                                      hb_ot_layout_table_type_t  table_type)
 286 {
 287   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 288
 289   return g.get_script_count ();
 290 }
 291
 292 hb_tag_t
 293 hb_ot_layout_table_get_script_tag (hb_ot_layout_t            *layout,
 294                                    hb_ot_layout_table_type_t  table_type,
 295                                    unsigned int               script_index)
 296 {
 297   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 298
 299   return g.get_script_tag (script_index);
 300 }
 301
 302 hb_bool_t
 303 hb_ot_layout_table_find_script (hb_ot_layout_t            *layout,
 304                                 hb_ot_layout_table_type_t  table_type,
 305                                 hb_tag_t                   script_tag,
 306                                 unsigned int              *script_index)
 307 {
 308   ASSERT_STATIC (NO_INDEX == HB_OT_LAYOUT_NO_SCRIPT_INDEX);
 309   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 310
 311   if (g.find_script_index (script_tag, script_index))
 312     return TRUE;
 313
 314   /* try finding 'DFLT' */
 315   if (g.find_script_index (HB_OT_LAYOUT_TAG_DEFAULT_SCRIPT, script_index))
 316     return FALSE;
 317
 318   /* try with 'dflt'; MS site has had typos and many fonts use it now :( */
 319   if (g.find_script_index (HB_OT_LAYOUT_TAG_DEFAULT_LANGUAGE, script_index))
 320     return FALSE;
 321
 322   if (script_index) *script_index = HB_OT_LAYOUT_NO_SCRIPT_INDEX;
 323   return FALSE;
 324 }
 325
 326 unsigned int
 327 hb_ot_layout_table_get_feature_count (hb_ot_layout_t            *layout,
 328                                       hb_ot_layout_table_type_t  table_type)
 329 {
 330   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 331
 332   return g.get_feature_count ();
 333 }
 334
 335 hb_tag_t
 336 hb_ot_layout_table_get_feature_tag (hb_ot_layout_t            *layout,
 337                                     hb_ot_layout_table_type_t  table_type,
 338                                     unsigned int               feature_index)
 339 {
 340   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 341
 342   return g.get_feature_tag (feature_index);
 343 }
 344
 345 hb_bool_t
 346 hb_ot_layout_table_find_feature (hb_ot_layout_t            *layout,
 347                                  hb_ot_layout_table_type_t  table_type,
 348                                  hb_tag_t                   feature_tag,
 349                                  unsigned int              *feature_index)
 350 {
 351   ASSERT_STATIC (NO_INDEX == HB_OT_LAYOUT_NO_FEATURE_INDEX);
 352   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 353
 354   if (g.find_feature_index (feature_tag, feature_index))
 355     return TRUE;
 356
 357   if (feature_index) *feature_index = HB_OT_LAYOUT_NO_FEATURE_INDEX;
 358   return FALSE;
 359 }
 360
 361 unsigned int
 362 hb_ot_layout_table_get_lookup_count (hb_ot_layout_t            *layout,
 363                                      hb_ot_layout_table_type_t  table_type)
 364 {
 365   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 366
 367   return g.get_lookup_count ();
 368 }
 369
 370
 371 unsigned int
 372 hb_ot_layout_script_get_language_count (hb_ot_layout_t            *layout,
 373                                         hb_ot_layout_table_type_t  table_type,
 374                                         unsigned int               script_index)
 375 {
 376   const Script &s = get_gsubgpos_table (layout, table_type).get_script (script_index);
 377
 378   return s.get_lang_sys_count ();
 379 }
 380
 381 hb_tag_t
 382 hb_ot_layout_script_get_language_tag (hb_ot_layout_t            *layout,
 383                                       hb_ot_layout_table_type_t  table_type,
 384                                       unsigned int               script_index,
 385                                       unsigned int               language_index)
 386 {
 387   const Script &s = get_gsubgpos_table (layout, table_type).get_script (script_index);
 388
 389   return s.get_lang_sys_tag (language_index);
 390 }
 391
 392 hb_bool_t
 393 hb_ot_layout_script_find_language (hb_ot_layout_t            *layout,
 394                                    hb_ot_layout_table_type_t  table_type,
 395                                    unsigned int               script_index,
 396                                    hb_tag_t                   language_tag,
 397                                    unsigned int              *language_index)
 398 {
 399   ASSERT_STATIC (NO_INDEX == HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX);
 400   const Script &s = get_gsubgpos_table (layout, table_type).get_script (script_index);
 401
 402   if (s.find_lang_sys_index (language_tag, language_index))
 403     return TRUE;
 404
 405   /* try with 'dflt'; MS site has had typos and many fonts use it now :( */
 406   if (s.find_lang_sys_index (HB_OT_LAYOUT_TAG_DEFAULT_LANGUAGE, language_index))
 407     return FALSE;
 408
 409   if (language_index) *language_index = HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX;
 410   return FALSE;
 411 }
 412
 413 hb_bool_t
 414 hb_ot_layout_language_get_required_feature_index (hb_ot_layout_t            *layout,
 415                                                   hb_ot_layout_table_type_t  table_type,
 416                                                   unsigned int               script_index,
 417                                                   unsigned int               language_index,
 418                                                   unsigned int              *feature_index)
 419 {
 420   const LangSys &l = get_gsubgpos_table (layout, table_type).get_script (script_index).get_lang_sys (language_index);
 421
 422   if (feature_index) *feature_index = l.get_required_feature_index ();
 423
 424   return l.has_required_feature ();
 425 }
 426
 427 unsigned int
 428 hb_ot_layout_language_get_feature_count (hb_ot_layout_t            *layout,
 429                                          hb_ot_layout_table_type_t  table_type,
 430                                          unsigned int               script_index,
 431                                          unsigned int               language_index)
 432 {
 433   const LangSys &l = get_gsubgpos_table (layout, table_type).get_script (script_index).get_lang_sys (language_index);
 434
 435   return l.get_feature_count ();
 436 }
 437
 438 unsigned int
 439 hb_ot_layout_language_get_feature_index (hb_ot_layout_t            *layout,
 440                                          hb_ot_layout_table_type_t  table_type,
 441                                          unsigned int               script_index,
 442                                          unsigned int               language_index,
 443                                          unsigned int               num_feature)
 444 {
 445   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 446   const LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
 447
 448   return l.get_feature_index (num_feature);
 449 }
 450
 451 hb_tag_t
 452 hb_ot_layout_language_get_feature_tag (hb_ot_layout_t            *layout,
 453                                        hb_ot_layout_table_type_t  table_type,
 454                                        unsigned int               script_index,
 455                                        unsigned int               language_index,
 456                                        unsigned int               num_feature)
 457 {
 458   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 459   const LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
 460   unsigned int feature_index = l.get_feature_index (num_feature);
 461
 462   return g.get_feature_tag (feature_index);
 463 }
 464
 465
 466 hb_bool_t
 467 hb_ot_layout_language_find_feature (hb_ot_layout_t            *layout,
 468                                     hb_ot_layout_table_type_t  table_type,
 469                                     unsigned int               script_index,
 470                                     unsigned int               language_index,
 471                                     hb_tag_t                   feature_tag,
 472                                     unsigned int              *feature_index)
 473 {
 474   ASSERT_STATIC (NO_INDEX == HB_OT_LAYOUT_NO_FEATURE_INDEX);
 475   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 476   const LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
 477   unsigned int i;
 478
 479   for (i = 0; i < l.get_feature_count (); i++) {
 480     unsigned int f_index = l.get_feature_index (i);
 481
 482     if (feature_tag == g.get_feature_tag (f_index)) {
 483       if (feature_index) *feature_index = f_index;
 484       return TRUE;
 485     }
 486   }
 487
 488   if (feature_index) *feature_index = HB_OT_LAYOUT_NO_FEATURE_INDEX;
 489   return FALSE;
 490 }
 491
 492 unsigned int
 493 hb_ot_layout_feature_get_lookup_count (hb_ot_layout_t            *layout,
 494                                        hb_ot_layout_table_type_t  table_type,
 495                                        unsigned int               feature_index)
 496 {
 497   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 498   const Feature &f = g.get_feature (feature_index);
 499
 500   return f.get_lookup_count ();
 501 }
 502
 503 unsigned int
 504 hb_ot_layout_feature_get_lookup_index (hb_ot_layout_t            *layout,
 505                                        hb_ot_layout_table_type_t  table_type,
 506                                        unsigned int               feature_index,
 507                                        unsigned int               num_lookup)
 508 {
 509   const GSUBGPOS &g = get_gsubgpos_table (layout, table_type);
 510   const Feature &f = g.get_feature (feature_index);
 511
 512   return f.get_lookup_index (num_lookup);
 513 }
 514
 515 /*
 516  * GSUB
 517  */
 518
 519 hb_bool_t
 520 hb_ot_layout_substitute_lookup (hb_ot_layout_t              *layout,
 521                                 hb_buffer_t                 *buffer,
 522                                 unsigned int                 lookup_index,
 523                                 hb_ot_layout_feature_mask_t  mask)
 524 {
 525   const GSUB &gsub = *(layout->gsub);
 526   const SubstLookup &l = gsub.get_lookup (lookup_index);
 527   unsigned int lookup_type = l.get_type ();
 528   unsigned int nesting_level_left = HB_OT_LAYOUT_MAX_NESTING_LEVEL;
 529   unsigned int context_length = NO_CONTEXT;
 530   bool handled, ret = false;
 531
 532   if (!l.is_reverse ()) {
 533
 534       /* in/out forward substitution */
 535       _hb_buffer_clear_output (buffer);
 536       buffer->in_pos = 0;
 537       while (buffer->in_pos < buffer->in_length) {
 538
 539         if ((~IN_PROPERTIES (buffer->in_pos) & mask) &&
 540             l.substitute (layout, buffer, context_length, nesting_level_left))
 541           ret = true;
 542         else
 543           _hb_buffer_copy_output_glyph (buffer);
 544
 545       }
 546       _hb_buffer_swap (buffer);
 547
 548   } else {
 549
 550       /* in-place backward substitution */
 551       buffer->in_pos = buffer->in_length - 1;
 552       do {
 553
 554         if ((~IN_PROPERTIES (buffer->in_pos) & mask) &&
 555             l.substitute (layout, buffer, context_length, nesting_level_left))
 556           ret = true;
 557         else
 558           buffer->in_pos--;
 559
 560       } while (buffer->in_pos);
 561
 562   }
 563
 564   return ret;
 565 }