src/hb-ot-layout.cc

   1 /*
   2  * Copyright © 1998-2004  David Turner and Werner Lemberg
   3  * Copyright © 2006  Behdad Esfahbod
   4  * Copyright © 2007,2008,2009  Red Hat, Inc.
   5  * Copyright © 2012,2013  Google, Inc.
   6  *
   7  *  This is part of HarfBuzz, a text shaping library.
   8  *
   9  * Permission is hereby granted, without written agreement and without
  10  * license or royalty fees, to use, copy, modify, and distribute this
  11  * software and its documentation for any purpose, provided that the
  12  * above copyright notice and the following two paragraphs appear in
  13  * all copies of this software.
  14  *
  15  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
  16  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
  17  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
  18  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
  19  * DAMAGE.
  20  *
  21  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
  22  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
  23  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
  24  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
  25  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
  26  *
  27  * Red Hat Author(s): Behdad Esfahbod
  28  * Google Author(s): Behdad Esfahbod
  29  */
  30
  31 #include "hb-open-type-private.hh"
  32 #include "hb-ot-layout-private.hh"
  33
  34 #include "hb-ot-layout-base-table.hh"
  35 #include "hb-ot-layout-gdef-table.hh"
  36 #include "hb-ot-layout-gsub-table.hh"
  37 #include "hb-ot-layout-gpos-table.hh"
  38 #include "hb-ot-layout-jstf-table.hh" // Just so we compile it; unused otherwise.
  39 #include "hb-ot-name-table.hh" // Just so we compile it; unused otherwise.
  40 #include "hb-ot-color-colr-table.hh"
  41 #include "hb-ot-color-cpal-table.hh"
  42
  43 #include "hb-ot-map-private.hh"
  44
  45
  46 #ifndef HB_NO_VISIBILITY
  47 const void * const OT::_hb_NullPool[HB_NULL_POOL_SIZE / sizeof (void *)] = {};
  48 #endif
  49
  50
  51 hb_ot_layout_t *
  52 _hb_ot_layout_create (hb_face_t *face)
  53 {
  54   hb_ot_layout_t *layout = (hb_ot_layout_t *) calloc (1, sizeof (hb_ot_layout_t));
  55   if (unlikely (!layout))
  56     return nullptr;
  57
  58   layout->gdef_blob = OT::Sanitizer<OT::GDEF>().sanitize (face->reference_table (HB_OT_TAG_GDEF));
  59   layout->gdef = OT::Sanitizer<OT::GDEF>::lock_instance (layout->gdef_blob);
  60
  61   layout->gsub_blob = OT::Sanitizer<OT::GSUB>().sanitize (face->reference_table (HB_OT_TAG_GSUB));
  62   layout->gsub = OT::Sanitizer<OT::GSUB>::lock_instance (layout->gsub_blob);
  63
  64   layout->gpos_blob = OT::Sanitizer<OT::GPOS>().sanitize (face->reference_table (HB_OT_TAG_GPOS));
  65   layout->gpos = OT::Sanitizer<OT::GPOS>::lock_instance (layout->gpos_blob);
  66
  67   layout->base.init (face);
  68   layout->colr.init (face);
  69   layout->cpal.init (face);
  70   layout->math.init (face);
  71   layout->fvar.init (face);
  72   layout->avar.init (face);
  73   layout->ankr.init (face);
  74   layout->kerx.init (face);
  75   layout->morx.init (face);
  76   layout->trak.init (face);
  77
  78   {
  79     /*
  80      * The ugly business of blacklisting individual fonts' tables happen here!
  81      * See this thread for why we finally had to bend in and do this:
  82      * https://lists.freedesktop.org/archives/harfbuzz/2016-February/005489.html
  83      */
  84     unsigned int gdef_len = hb_blob_get_length (layout->gdef_blob);
  85     unsigned int gsub_len = hb_blob_get_length (layout->gsub_blob);
  86     unsigned int gpos_len = hb_blob_get_length (layout->gpos_blob);
  87     if (0
  88       /* sha1sum:c5ee92f0bca4bfb7d06c4d03e8cf9f9cf75d2e8a Windows 7? timesi.ttf */
  89       || (442 == gdef_len && 42038 == gpos_len && 2874 == gsub_len)
  90       /* sha1sum:37fc8c16a0894ab7b749e35579856c73c840867b Windows 7? timesbi.ttf */
  91       || (430 == gdef_len && 40662 == gpos_len && 2874 == gsub_len)
  92       /* sha1sum:19fc45110ea6cd3cdd0a5faca256a3797a069a80 Windows 7 timesi.ttf */
  93       || (442 == gdef_len && 39116 == gpos_len && 2874 == gsub_len)
  94       /* sha1sum:6d2d3c9ed5b7de87bc84eae0df95ee5232ecde26 Windows 7 timesbi.ttf */
  95       || (430 == gdef_len && 39374 == gpos_len && 2874 == gsub_len)
  96       /* sha1sum:8583225a8b49667c077b3525333f84af08c6bcd8 OS X 10.11.3 Times New Roman Italic.ttf */
  97       || (490 == gdef_len && 41638 == gpos_len && 3046 == gsub_len)
  98       /* sha1sum:ec0f5a8751845355b7c3271d11f9918a966cb8c9 OS X 10.11.3 Times New Roman Bold Italic.ttf */
  99       || (478 == gdef_len && 41902 == gpos_len && 3046 == gsub_len)
 100     )
 101     {
 102       /* In certain versions of Times New Roman Italic and Bold Italic,
 103        * ASCII double quotation mark U+0022, mapped to glyph 5, has wrong
 104        * glyph class 3 (mark) in GDEF.  Nuke the GDEF to avoid zero-width
 105        * double-quote.  See:
 106        * https://lists.freedesktop.org/archives/harfbuzz/2016-February/005489.html
 107        */
 108      if (3 == layout->gdef->get_glyph_class (5))
 109        layout->gdef = &OT::Null(OT::GDEF);
 110     }
 111     else if (0
 112       /* sha1sum:96eda93f7d33e79962451c6c39a6b51ee893ce8c  tahoma.ttf from Windows 8 */
 113       || (898 == gdef_len && 46470 == gpos_len && 12554 == gsub_len)
 114       /* sha1sum:20928dc06014e0cd120b6fc942d0c3b1a46ac2bc  tahomabd.ttf from Windows 8 */
 115       || (910 == gdef_len && 47732 == gpos_len && 12566 == gsub_len)
 116       /* sha1sum:4f95b7e4878f60fa3a39ca269618dfde9721a79e  tahoma.ttf from Windows 8.1 */
 117       || (928 == gdef_len && 59332 == gpos_len && 23298 == gsub_len)
 118       /* sha1sum:6d400781948517c3c0441ba42acb309584b73033  tahomabd.ttf from Windows 8.1 */
 119       || (940 == gdef_len && 60732 == gpos_len && 23310 == gsub_len)
 120       /* tahoma.ttf v6.04 from Windows 8.1 x64, see https://bugzilla.mozilla.org/show_bug.cgi?id=1279925 */
 121       || (964 == gdef_len && 60072 == gpos_len && 23836 == gsub_len)
 122       /* tahomabd.ttf v6.04 from Windows 8.1 x64, see https://bugzilla.mozilla.org/show_bug.cgi?id=1279925 */
 123       || (976 == gdef_len && 61456 == gpos_len && 23832 == gsub_len)
 124       /* sha1sum:e55fa2dfe957a9f7ec26be516a0e30b0c925f846  tahoma.ttf from Windows 10 */
 125       || (994 == gdef_len && 60336 == gpos_len && 24474 == gsub_len)
 126       /* sha1sum:7199385abb4c2cc81c83a151a7599b6368e92343  tahomabd.ttf from Windows 10 */
 127       || (1006 == gdef_len && 61740 == gpos_len && 24470 == gsub_len)
 128       /* tahoma.ttf v6.91 from Windows 10 x64, see https://bugzilla.mozilla.org/show_bug.cgi?id=1279925 */
 129       || (1006 == gdef_len && 61346 == gpos_len && 24576 == gsub_len)
 130       /* tahomabd.ttf v6.91 from Windows 10 x64, see https://bugzilla.mozilla.org/show_bug.cgi?id=1279925 */
 131       || (1018 == gdef_len && 62828 == gpos_len && 24572 == gsub_len)
 132       /* sha1sum:b9c84d820c49850d3d27ec498be93955b82772b5  tahoma.ttf from Windows 10 AU */
 133       || (1006 == gdef_len && 61352 == gpos_len && 24576 == gsub_len)
 134       /* sha1sum:2bdfaab28174bdadd2f3d4200a30a7ae31db79d2  tahomabd.ttf from Windows 10 AU */
 135       || (1018 == gdef_len && 62834 == gpos_len && 24572 == gsub_len)
 136       /* sha1sum:b0d36cf5a2fbe746a3dd277bffc6756a820807a7  Tahoma.ttf from Mac OS X 10.9 */
 137       || (832 == gdef_len && 47162 == gpos_len && 7324 == gsub_len)
 138       /* sha1sum:12fc4538e84d461771b30c18b5eb6bd434e30fba  Tahoma Bold.ttf from Mac OS X 10.9 */
 139       || (844 == gdef_len && 45474 == gpos_len && 7302 == gsub_len)
 140       /* sha1sum:eb8afadd28e9cf963e886b23a30b44ab4fd83acc  himalaya.ttf from Windows 7 */
 141       || (180 == gdef_len && 7254 == gpos_len && 13054 == gsub_len)
 142       /* sha1sum:73da7f025b238a3f737aa1fde22577a6370f77b0  himalaya.ttf from Windows 8 */
 143       || (192 == gdef_len && 7254 == gpos_len && 12638 == gsub_len)
 144       /* sha1sum:6e80fd1c0b059bbee49272401583160dc1e6a427  himalaya.ttf from Windows 8.1 */
 145       || (192 == gdef_len && 7254 == gpos_len && 12690 == gsub_len)
 146       /* 8d9267aea9cd2c852ecfb9f12a6e834bfaeafe44  cantarell-fonts-0.0.21/otf/Cantarell-Regular.otf */
 147       /* 983988ff7b47439ab79aeaf9a45bd4a2c5b9d371  cantarell-fonts-0.0.21/otf/Cantarell-Oblique.otf */
 148       || (188 == gdef_len && 3852 == gpos_len && 248 == gsub_len)
 149       /* 2c0c90c6f6087ffbfea76589c93113a9cbb0e75f  cantarell-fonts-0.0.21/otf/Cantarell-Bold.otf */
 150       /* 55461f5b853c6da88069ffcdf7f4dd3f8d7e3e6b  cantarell-fonts-0.0.21/otf/Cantarell-Bold-Oblique.otf */
 151       || (188 == gdef_len && 3426 == gpos_len && 264 == gsub_len)
 152       /* d125afa82a77a6475ac0e74e7c207914af84b37a padauk-2.80/Padauk.ttf RHEL 7.2 */
 153       || (1058 == gdef_len && 11818 == gpos_len && 47032 == gsub_len)
 154       /* 0f7b80437227b90a577cc078c0216160ae61b031 padauk-2.80/Padauk-Bold.ttf RHEL 7.2*/
 155       || (1046 == gdef_len && 12600 == gpos_len && 47030 == gsub_len)
 156       /* d3dde9aa0a6b7f8f6a89ef1002e9aaa11b882290 padauk-2.80/Padauk.ttf Ubuntu 16.04 */
 157       || (1058 == gdef_len && 16770 == gpos_len && 71796 == gsub_len)
 158       /* 5f3c98ccccae8a953be2d122c1b3a77fd805093f padauk-2.80/Padauk-Bold.ttf Ubuntu 16.04 */
 159       || (1046 == gdef_len && 17862 == gpos_len && 71790 == gsub_len)
 160       /* 6c93b63b64e8b2c93f5e824e78caca555dc887c7 padauk-2.80/Padauk-book.ttf */
 161       || (1046 == gdef_len && 17112 == gpos_len && 71788 == gsub_len)
 162       /* d89b1664058359b8ec82e35d3531931125991fb9 padauk-2.80/Padauk-bookbold.ttf */
 163       || (1058 == gdef_len && 17514 == gpos_len && 71794 == gsub_len)
 164       /* 824cfd193aaf6234b2b4dc0cf3c6ef576c0d00ef padauk-3.0/Padauk-book.ttf */
 165       || (1330 == gdef_len && 57938 == gpos_len && 109904 == gsub_len)
 166       /* 91fcc10cf15e012d27571e075b3b4dfe31754a8a padauk-3.0/Padauk-bookbold.ttf */
 167       || (1330 == gdef_len && 58972 == gpos_len && 109904 == gsub_len)
 168       /* sha1sum: c26e41d567ed821bed997e937bc0c41435689e85  Padauk.ttf
 169        *  "Padauk Regular" "Version 2.5", see https://crbug.com/681813 */
 170       || (1004 == gdef_len && 14836 == gpos_len && 59092 == gsub_len)
 171     )
 172     {
 173       /* Many versions of Tahoma have bad GDEF tables that incorrectly classify some spacing marks
 174        * such as certain IPA symbols as glyph class 3. So do older versions of Microsoft Himalaya,
 175        * and the version of Cantarell shipped by Ubuntu 16.04.
 176        * Nuke the GDEF tables of these fonts to avoid unwanted width-zeroing.
 177        * See https://bugzilla.mozilla.org/show_bug.cgi?id=1279925
 178        *     https://bugzilla.mozilla.org/show_bug.cgi?id=1279693
 179        *     https://bugzilla.mozilla.org/show_bug.cgi?id=1279875
 180        */
 181       layout->gdef = &OT::Null(OT::GDEF);
 182     }
 183   }
 184
 185   layout->gsub_lookup_count = layout->gsub->get_lookup_count ();
 186   layout->gpos_lookup_count = layout->gpos->get_lookup_count ();
 187
 188   layout->gsub_accels = (hb_ot_layout_lookup_accelerator_t *) calloc (layout->gsub->get_lookup_count (), sizeof (hb_ot_layout_lookup_accelerator_t));
 189   layout->gpos_accels = (hb_ot_layout_lookup_accelerator_t *) calloc (layout->gpos->get_lookup_count (), sizeof (hb_ot_layout_lookup_accelerator_t));
 190
 191   if (unlikely ((layout->gsub_lookup_count && !layout->gsub_accels) ||
 192                 (layout->gpos_lookup_count && !layout->gpos_accels)))
 193   {
 194     _hb_ot_layout_destroy (layout);
 195     return nullptr;
 196   }
 197
 198   for (unsigned int i = 0; i < layout->gsub_lookup_count; i++)
 199     layout->gsub_accels[i].init (layout->gsub->get_lookup (i));
 200   for (unsigned int i = 0; i < layout->gpos_lookup_count; i++)
 201     layout->gpos_accels[i].init (layout->gpos->get_lookup (i));
 202
 203   return layout;
 204 }
 205
 206 void
 207 _hb_ot_layout_destroy (hb_ot_layout_t *layout)
 208 {
 209   if (layout->gsub_accels)
 210     for (unsigned int i = 0; i < layout->gsub_lookup_count; i++)
 211       layout->gsub_accels[i].fini ();
 212   if (layout->gpos_accels)
 213     for (unsigned int i = 0; i < layout->gpos_lookup_count; i++)
 214       layout->gpos_accels[i].fini ();
 215
 216   free (layout->gsub_accels);
 217   free (layout->gpos_accels);
 218
 219   hb_blob_destroy (layout->gdef_blob);
 220   hb_blob_destroy (layout->gsub_blob);
 221   hb_blob_destroy (layout->gpos_blob);
 222
 223   layout->base.fini ();
 224   layout->colr.fini ();
 225   layout->cpal.fini ();
 226   layout->math.fini ();
 227   layout->fvar.fini ();
 228   layout->avar.fini ();
 229   layout->ankr.fini ();
 230   layout->kerx.fini ();
 231   layout->morx.fini ();
 232   layout->trak.fini ();
 233
 234   free (layout);
 235 }
 236
 237 // static inline const OT::BASE&
 238 // _get_base (hb_face_t *face)
 239 // {
 240 //   if (unlikely (!hb_ot_shaper_face_data_ensure (face))) return OT::Null(OT::BASE);
 241 //   hb_ot_layout_t * layout = hb_ot_layout_from_face (face);
 242 //   return *(layout->base.get ());
 243 // }
 244
 245 static inline const OT::GDEF&
 246 _get_gdef (hb_face_t *face)
 247 {
 248   if (unlikely (!hb_ot_shaper_face_data_ensure (face))) return OT::Null(OT::GDEF);
 249   return *hb_ot_layout_from_face (face)->gdef;
 250 }
 251 static inline const OT::GSUB&
 252 _get_gsub (hb_face_t *face)
 253 {
 254   if (unlikely (!hb_ot_shaper_face_data_ensure (face))) return OT::Null(OT::GSUB);
 255   return *hb_ot_layout_from_face (face)->gsub;
 256 }
 257 static inline const OT::GPOS&
 258 _get_gpos (hb_face_t *face)
 259 {
 260   if (unlikely (!hb_ot_shaper_face_data_ensure (face))) return OT::Null(OT::GPOS);
 261   return *hb_ot_layout_from_face (face)->gpos;
 262 }
 263
 264 /*
 265  * GDEF
 266  */
 267
 268 hb_bool_t
 269 hb_ot_layout_has_glyph_classes (hb_face_t *face)
 270 {
 271   return _get_gdef (face).has_glyph_classes ();
 272 }
 273
 274 /**
 275  * hb_ot_layout_get_glyph_class:
 276  *
 277  * Since: 0.9.7
 278  **/
 279 hb_ot_layout_glyph_class_t
 280 hb_ot_layout_get_glyph_class (hb_face_t      *face,
 281                               hb_codepoint_t  glyph)
 282 {
 283   return (hb_ot_layout_glyph_class_t) _get_gdef (face).get_glyph_class (glyph);
 284 }
 285
 286 /**
 287  * hb_ot_layout_get_glyphs_in_class:
 288  *
 289  * Since: 0.9.7
 290  **/
 291 void
 292 hb_ot_layout_get_glyphs_in_class (hb_face_t                  *face,
 293                                   hb_ot_layout_glyph_class_t  klass,
 294                                   hb_set_t                   *glyphs /* OUT */)
 295 {
 296   return _get_gdef (face).get_glyphs_in_class (klass, glyphs);
 297 }
 298
 299 unsigned int
 300 hb_ot_layout_get_attach_points (hb_face_t      *face,
 301                                 hb_codepoint_t  glyph,
 302                                 unsigned int    start_offset,
 303                                 unsigned int   *point_count /* IN/OUT */,
 304                                 unsigned int   *point_array /* OUT */)
 305 {
 306   return _get_gdef (face).get_attach_points (glyph, start_offset, point_count, point_array);
 307 }
 308
 309 unsigned int
 310 hb_ot_layout_get_ligature_carets (hb_font_t      *font,
 311                                   hb_direction_t  direction,
 312                                   hb_codepoint_t  glyph,
 313                                   unsigned int    start_offset,
 314                                   unsigned int   *caret_count /* IN/OUT */,
 315                                   hb_position_t  *caret_array /* OUT */)
 316 {
 317   return _get_gdef (font->face).get_lig_carets (font, direction, glyph, start_offset, caret_count, caret_array);
 318 }
 319
 320
 321 /*
 322  * GSUB/GPOS
 323  */
 324
 325 static const OT::GSUBGPOS&
 326 get_gsubgpos_table (hb_face_t *face,
 327                     hb_tag_t   table_tag)
 328 {
 329   switch (table_tag) {
 330     case HB_OT_TAG_GSUB: return _get_gsub (face);
 331     case HB_OT_TAG_GPOS: return _get_gpos (face);
 332     default:             return OT::Null(OT::GSUBGPOS);
 333   }
 334 }
 335
 336
 337 unsigned int
 338 hb_ot_layout_table_get_script_tags (hb_face_t    *face,
 339                                     hb_tag_t      table_tag,
 340                                     unsigned int  start_offset,
 341                                     unsigned int *script_count /* IN/OUT */,
 342                                     hb_tag_t     *script_tags /* OUT */)
 343 {
 344   const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
 345
 346   return g.get_script_tags (start_offset, script_count, script_tags);
 347 }
 348
 349 #define HB_OT_TAG_LATIN_SCRIPT          HB_TAG ('l', 'a', 't', 'n')
 350
 351 hb_bool_t
 352 hb_ot_layout_table_find_script (hb_face_t    *face,
 353                                 hb_tag_t      table_tag,
 354                                 hb_tag_t      script_tag,
 355                                 unsigned int *script_index)
 356 {
 357   static_assert ((OT::Index::NOT_FOUND_INDEX == HB_OT_LAYOUT_NO_SCRIPT_INDEX), "");
 358   const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
 359
 360   if (g.find_script_index (script_tag, script_index))
 361     return true;
 362
 363   /* try finding 'DFLT' */
 364   if (g.find_script_index (HB_OT_TAG_DEFAULT_SCRIPT, script_index))
 365     return false;
 366
 367   /* try with 'dflt'; MS site has had typos and many fonts use it now :(.
 368    * including many versions of DejaVu Sans Mono! */
 369   if (g.find_script_index (HB_OT_TAG_DEFAULT_LANGUAGE, script_index))
 370     return false;
 371
 372   /* try with 'latn'; some old fonts put their features there even though
 373      they're really trying to support Thai, for example :( */
 374   if (g.find_script_index (HB_OT_TAG_LATIN_SCRIPT, script_index))
 375     return false;
 376
 377   if (script_index) *script_index = HB_OT_LAYOUT_NO_SCRIPT_INDEX;
 378   return false;
 379 }
 380
 381 hb_bool_t
 382 hb_ot_layout_table_choose_script (hb_face_t      *face,
 383                                   hb_tag_t        table_tag,
 384                                   const hb_tag_t *script_tags,
 385                                   unsigned int   *script_index,
 386                                   hb_tag_t       *chosen_script)
 387 {
 388   static_assert ((OT::Index::NOT_FOUND_INDEX == HB_OT_LAYOUT_NO_SCRIPT_INDEX), "");
 389   const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
 390
 391   while (*script_tags)
 392   {
 393     if (g.find_script_index (*script_tags, script_index)) {
 394       if (chosen_script)
 395         *chosen_script = *script_tags;
 396       return true;
 397     }
 398     script_tags++;
 399   }
 400
 401   /* try finding 'DFLT' */
 402   if (g.find_script_index (HB_OT_TAG_DEFAULT_SCRIPT, script_index)) {
 403     if (chosen_script)
 404       *chosen_script = HB_OT_TAG_DEFAULT_SCRIPT;
 405     return false;
 406   }
 407
 408   /* try with 'dflt'; MS site has had typos and many fonts use it now :( */
 409   if (g.find_script_index (HB_OT_TAG_DEFAULT_LANGUAGE, script_index)) {
 410     if (chosen_script)
 411       *chosen_script = HB_OT_TAG_DEFAULT_LANGUAGE;
 412     return false;
 413   }
 414
 415   /* try with 'latn'; some old fonts put their features there even though
 416      they're really trying to support Thai, for example :( */
 417   if (g.find_script_index (HB_OT_TAG_LATIN_SCRIPT, script_index)) {
 418     if (chosen_script)
 419       *chosen_script = HB_OT_TAG_LATIN_SCRIPT;
 420     return false;
 421   }
 422
 423   if (script_index) *script_index = HB_OT_LAYOUT_NO_SCRIPT_INDEX;
 424   if (chosen_script)
 425     *chosen_script = HB_OT_LAYOUT_NO_SCRIPT_INDEX;
 426   return false;
 427 }
 428
 429 unsigned int
 430 hb_ot_layout_table_get_feature_tags (hb_face_t    *face,
 431                                      hb_tag_t      table_tag,
 432                                      unsigned int  start_offset,
 433                                      unsigned int *feature_count /* IN/OUT */,
 434                                      hb_tag_t     *feature_tags /* OUT */)
 435 {
 436   const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
 437
 438   return g.get_feature_tags (start_offset, feature_count, feature_tags);
 439 }
 440
 441 hb_bool_t
 442 hb_ot_layout_table_find_feature (hb_face_t    *face,
 443                                  hb_tag_t      table_tag,
 444                                  hb_tag_t      feature_tag,
 445                                  unsigned int *feature_index)
 446 {
 447   static_assert ((OT::Index::NOT_FOUND_INDEX == HB_OT_LAYOUT_NO_FEATURE_INDEX), "");
 448   const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
 449
 450   unsigned int num_features = g.get_feature_count ();
 451   for (unsigned int i = 0; i < num_features; i++)
 452   {
 453     if (feature_tag == g.get_feature_tag (i)) {
 454       if (feature_index) *feature_index = i;
 455       return true;
 456     }
 457   }
 458
 459   if (feature_index) *feature_index = HB_OT_LAYOUT_NO_FEATURE_INDEX;
 460   return false;
 461 }
 462
 463
 464 unsigned int
 465 hb_ot_layout_script_get_language_tags (hb_face_t    *face,
 466                                        hb_tag_t      table_tag,
 467                                        unsigned int  script_index,
 468                                        unsigned int  start_offset,
 469                                        unsigned int *language_count /* IN/OUT */,
 470                                        hb_tag_t     *language_tags /* OUT */)
 471 {
 472   const OT::Script &s = get_gsubgpos_table (face, table_tag).get_script (script_index);
 473
 474   return s.get_lang_sys_tags (start_offset, language_count, language_tags);
 475 }
 476
 477 hb_bool_t
 478 hb_ot_layout_script_find_language (hb_face_t    *face,
 479                                    hb_tag_t      table_tag,
 480                                    unsigned int  script_index,
 481                                    hb_tag_t      language_tag,
 482                                    unsigned int *language_index)
 483 {
 484   static_assert ((OT::Index::NOT_FOUND_INDEX == HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX), "");
 485   const OT::Script &s = get_gsubgpos_table (face, table_tag).get_script (script_index);
 486
 487   if (s.find_lang_sys_index (language_tag, language_index))
 488     return true;
 489
 490   /* try with 'dflt'; MS site has had typos and many fonts use it now :( */
 491   if (s.find_lang_sys_index (HB_OT_TAG_DEFAULT_LANGUAGE, language_index))
 492     return false;
 493
 494   if (language_index) *language_index = HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX;
 495   return false;
 496 }
 497
 498 hb_bool_t
 499 hb_ot_layout_language_get_required_feature_index (hb_face_t    *face,
 500                                                   hb_tag_t      table_tag,
 501                                                   unsigned int  script_index,
 502                                                   unsigned int  language_index,
 503                                                   unsigned int *feature_index)
 504 {
 505   return hb_ot_layout_language_get_required_feature (face,
 506                                                      table_tag,
 507                                                      script_index,
 508                                                      language_index,
 509                                                      feature_index,
 510                                                      nullptr);
 511 }
 512
 513 /**
 514  * hb_ot_layout_language_get_required_feature:
 515  *
 516  * Since: 0.9.30
 517  **/
 518 hb_bool_t
 519 hb_ot_layout_language_get_required_feature (hb_face_t    *face,
 520                                             hb_tag_t      table_tag,
 521                                             unsigned int  script_index,
 522                                             unsigned int  language_index,
 523                                             unsigned int *feature_index,
 524                                             hb_tag_t     *feature_tag)
 525 {
 526   const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
 527   const OT::LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
 528
 529   unsigned int index = l.get_required_feature_index ();
 530   if (feature_index) *feature_index = index;
 531   if (feature_tag) *feature_tag = g.get_feature_tag (index);
 532
 533   return l.has_required_feature ();
 534 }
 535
 536 unsigned int
 537 hb_ot_layout_language_get_feature_indexes (hb_face_t    *face,
 538                                            hb_tag_t      table_tag,
 539                                            unsigned int  script_index,
 540                                            unsigned int  language_index,
 541                                            unsigned int  start_offset,
 542                                            unsigned int *feature_count /* IN/OUT */,
 543                                            unsigned int *feature_indexes /* OUT */)
 544 {
 545   const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
 546   const OT::LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
 547
 548   return l.get_feature_indexes (start_offset, feature_count, feature_indexes);
 549 }
 550
 551 unsigned int
 552 hb_ot_layout_language_get_feature_tags (hb_face_t    *face,
 553                                         hb_tag_t      table_tag,
 554                                         unsigned int  script_index,
 555                                         unsigned int  language_index,
 556                                         unsigned int  start_offset,
 557                                         unsigned int *feature_count /* IN/OUT */,
 558                                         hb_tag_t     *feature_tags /* OUT */)
 559 {
 560   const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
 561   const OT::LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
 562
 563   static_assert ((sizeof (unsigned int) == sizeof (hb_tag_t)), "");
 564   unsigned int ret = l.get_feature_indexes (start_offset, feature_count, (unsigned int *) feature_tags);
 565
 566   if (feature_tags) {
 567     unsigned int count = *feature_count;
 568     for (unsigned int i = 0; i < count; i++)
 569       feature_tags[i] = g.get_feature_tag ((unsigned int) feature_tags[i]);
 570   }
 571
 572   return ret;
 573 }
 574
 575
 576 hb_bool_t
 577 hb_ot_layout_language_find_feature (hb_face_t    *face,
 578                                     hb_tag_t      table_tag,
 579                                     unsigned int  script_index,
 580                                     unsigned int  language_index,
 581                                     hb_tag_t      feature_tag,
 582                                     unsigned int *feature_index)
 583 {
 584   static_assert ((OT::Index::NOT_FOUND_INDEX == HB_OT_LAYOUT_NO_FEATURE_INDEX), "");
 585   const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
 586   const OT::LangSys &l = g.get_script (script_index).get_lang_sys (language_index);
 587
 588   unsigned int num_features = l.get_feature_count ();
 589   for (unsigned int i = 0; i < num_features; i++) {
 590     unsigned int f_index = l.get_feature_index (i);
 591
 592     if (feature_tag == g.get_feature_tag (f_index)) {
 593       if (feature_index) *feature_index = f_index;
 594       return true;
 595     }
 596   }
 597
 598   if (feature_index) *feature_index = HB_OT_LAYOUT_NO_FEATURE_INDEX;
 599   return false;
 600 }
 601
 602 /**
 603  * hb_ot_layout_feature_get_lookups:
 604  *
 605  * Since: 0.9.7
 606  **/
 607 unsigned int
 608 hb_ot_layout_feature_get_lookups (hb_face_t    *face,
 609                                   hb_tag_t      table_tag,
 610                                   unsigned int  feature_index,
 611                                   unsigned int  start_offset,
 612                                   unsigned int *lookup_count /* IN/OUT */,
 613                                   unsigned int *lookup_indexes /* OUT */)
 614 {
 615   return hb_ot_layout_feature_with_variations_get_lookups (face,
 616                                                            table_tag,
 617                                                            feature_index,
 618                                                            HB_OT_LAYOUT_NO_VARIATIONS_INDEX,
 619                                                            start_offset,
 620                                                            lookup_count,
 621                                                            lookup_indexes);
 622 }
 623
 624 /**
 625  * hb_ot_layout_table_get_lookup_count:
 626  *
 627  * Since: 0.9.22
 628  **/
 629 unsigned int
 630 hb_ot_layout_table_get_lookup_count (hb_face_t    *face,
 631                                      hb_tag_t      table_tag)
 632 {
 633   if (unlikely (!hb_ot_shaper_face_data_ensure (face))) return 0;
 634   switch (table_tag)
 635   {
 636     case HB_OT_TAG_GSUB:
 637     {
 638       return hb_ot_layout_from_face (face)->gsub_lookup_count;
 639     }
 640     case HB_OT_TAG_GPOS:
 641     {
 642       return hb_ot_layout_from_face (face)->gpos_lookup_count;
 643     }
 644   }
 645   return 0;
 646 }
 647
 648 static void
 649 _hb_ot_layout_collect_lookups_lookups (hb_face_t      *face,
 650                                        hb_tag_t        table_tag,
 651                                        unsigned int    feature_index,
 652                                        hb_set_t       *lookup_indexes /* OUT */)
 653 {
 654   unsigned int lookup_indices[32];
 655   unsigned int offset, len;
 656
 657   offset = 0;
 658   do {
 659     len = ARRAY_LENGTH (lookup_indices);
 660     hb_ot_layout_feature_get_lookups (face,
 661                                       table_tag,
 662                                       feature_index,
 663                                       offset, &len,
 664                                       lookup_indices);
 665
 666     for (unsigned int i = 0; i < len; i++)
 667       lookup_indexes->add (lookup_indices[i]);
 668
 669     offset += len;
 670   } while (len == ARRAY_LENGTH (lookup_indices));
 671 }
 672
 673 static void
 674 _hb_ot_layout_collect_lookups_features (hb_face_t      *face,
 675                                         hb_tag_t        table_tag,
 676                                         unsigned int    script_index,
 677                                         unsigned int    language_index,
 678                                         const hb_tag_t *features,
 679                                         hb_set_t       *lookup_indexes /* OUT */)
 680 {
 681   if (!features)
 682   {
 683     unsigned int required_feature_index;
 684     if (hb_ot_layout_language_get_required_feature (face,
 685                                                     table_tag,
 686                                                     script_index,
 687                                                     language_index,
 688                                                     &required_feature_index,
 689                                                     nullptr))
 690       _hb_ot_layout_collect_lookups_lookups (face,
 691                                              table_tag,
 692                                              required_feature_index,
 693                                              lookup_indexes);
 694
 695     /* All features */
 696     unsigned int feature_indices[32];
 697     unsigned int offset, len;
 698
 699     offset = 0;
 700     do {
 701       len = ARRAY_LENGTH (feature_indices);
 702       hb_ot_layout_language_get_feature_indexes (face,
 703                                                  table_tag,
 704                                                  script_index,
 705                                                  language_index,
 706                                                  offset, &len,
 707                                                  feature_indices);
 708
 709       for (unsigned int i = 0; i < len; i++)
 710         _hb_ot_layout_collect_lookups_lookups (face,
 711                                                table_tag,
 712                                                feature_indices[i],
 713                                                lookup_indexes);
 714
 715       offset += len;
 716     } while (len == ARRAY_LENGTH (feature_indices));
 717   }
 718   else
 719   {
 720     for (; *features; features++)
 721     {
 722       unsigned int feature_index;
 723       if (hb_ot_layout_language_find_feature (face,
 724                                               table_tag,
 725                                               script_index,
 726                                               language_index,
 727                                               *features,
 728                                               &feature_index))
 729         _hb_ot_layout_collect_lookups_lookups (face,
 730                                                table_tag,
 731                                                feature_index,
 732                                                lookup_indexes);
 733     }
 734   }
 735 }
 736
 737 static void
 738 _hb_ot_layout_collect_lookups_languages (hb_face_t      *face,
 739                                          hb_tag_t        table_tag,
 740                                          unsigned int    script_index,
 741                                          const hb_tag_t *languages,
 742                                          const hb_tag_t *features,
 743                                          hb_set_t       *lookup_indexes /* OUT */)
 744 {
 745   _hb_ot_layout_collect_lookups_features (face,
 746                                           table_tag,
 747                                           script_index,
 748                                           HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX,
 749                                           features,
 750                                           lookup_indexes);
 751
 752   if (!languages)
 753   {
 754     /* All languages */
 755     unsigned int count = hb_ot_layout_script_get_language_tags (face,
 756                                                                 table_tag,
 757                                                                 script_index,
 758                                                                 0, nullptr, nullptr);
 759     for (unsigned int language_index = 0; language_index < count; language_index++)
 760       _hb_ot_layout_collect_lookups_features (face,
 761                                               table_tag,
 762                                               script_index,
 763                                               language_index,
 764                                               features,
 765                                               lookup_indexes);
 766   }
 767   else
 768   {
 769     for (; *languages; languages++)
 770     {
 771       unsigned int language_index;
 772       if (hb_ot_layout_script_find_language (face,
 773                                              table_tag,
 774                                              script_index,
 775                                              *languages,
 776                                              &language_index))
 777         _hb_ot_layout_collect_lookups_features (face,
 778                                                 table_tag,
 779                                                 script_index,
 780                                                 language_index,
 781                                                 features,
 782                                                 lookup_indexes);
 783     }
 784   }
 785 }
 786
 787 /**
 788  * hb_ot_layout_collect_lookups:
 789  *
 790  * Since: 0.9.8
 791  **/
 792 void
 793 hb_ot_layout_collect_lookups (hb_face_t      *face,
 794                               hb_tag_t        table_tag,
 795                               const hb_tag_t *scripts,
 796                               const hb_tag_t *languages,
 797                               const hb_tag_t *features,
 798                               hb_set_t       *lookup_indexes /* OUT */)
 799 {
 800   if (!scripts)
 801   {
 802     /* All scripts */
 803     unsigned int count = hb_ot_layout_table_get_script_tags (face,
 804                                                              table_tag,
 805                                                              0, nullptr, nullptr);
 806     for (unsigned int script_index = 0; script_index < count; script_index++)
 807       _hb_ot_layout_collect_lookups_languages (face,
 808                                                table_tag,
 809                                                script_index,
 810                                                languages,
 811                                                features,
 812                                                lookup_indexes);
 813   }
 814   else
 815   {
 816     for (; *scripts; scripts++)
 817     {
 818       unsigned int script_index;
 819       if (hb_ot_layout_table_find_script (face,
 820                                           table_tag,
 821                                           *scripts,
 822                                           &script_index))
 823         _hb_ot_layout_collect_lookups_languages (face,
 824                                                  table_tag,
 825                                                  script_index,
 826                                                  languages,
 827                                                  features,
 828                                                  lookup_indexes);
 829     }
 830   }
 831 }
 832
 833 /**
 834  * hb_ot_layout_lookup_collect_glyphs:
 835  *
 836  * Since: 0.9.7
 837  **/
 838 void
 839 hb_ot_layout_lookup_collect_glyphs (hb_face_t    *face,
 840                                     hb_tag_t      table_tag,
 841                                     unsigned int  lookup_index,
 842                                     hb_set_t     *glyphs_before, /* OUT. May be nullptr */
 843                                     hb_set_t     *glyphs_input,  /* OUT. May be nullptr */
 844                                     hb_set_t     *glyphs_after,  /* OUT. May be nullptr */
 845                                     hb_set_t     *glyphs_output  /* OUT. May be nullptr */)
 846 {
 847   if (unlikely (!hb_ot_shaper_face_data_ensure (face))) return;
 848
 849   OT::hb_collect_glyphs_context_t c (face,
 850                                      glyphs_before,
 851                                      glyphs_input,
 852                                      glyphs_after,
 853                                      glyphs_output);
 854
 855   switch (table_tag)
 856   {
 857     case HB_OT_TAG_GSUB:
 858     {
 859       const OT::SubstLookup& l = hb_ot_layout_from_face (face)->gsub->get_lookup (lookup_index);
 860       l.collect_glyphs (&c);
 861       return;
 862     }
 863     case HB_OT_TAG_GPOS:
 864     {
 865       const OT::PosLookup& l = hb_ot_layout_from_face (face)->gpos->get_lookup (lookup_index);
 866       l.collect_glyphs (&c);
 867       return;
 868     }
 869   }
 870 }
 871
 872
 873 /* Variations support */
 874
 875 hb_bool_t
 876 hb_ot_layout_table_find_feature_variations (hb_face_t    *face,
 877                                             hb_tag_t      table_tag,
 878                                             const int    *coords,
 879                                             unsigned int  num_coords,
 880                                             unsigned int *variations_index /* out */)
 881 {
 882   const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
 883
 884   return g.find_variations_index (coords, num_coords, variations_index);
 885 }
 886
 887 unsigned int
 888 hb_ot_layout_feature_with_variations_get_lookups (hb_face_t    *face,
 889                                                   hb_tag_t      table_tag,
 890                                                   unsigned int  feature_index,
 891                                                   unsigned int  variations_index,
 892                                                   unsigned int  start_offset,
 893                                                   unsigned int *lookup_count /* IN/OUT */,
 894                                                   unsigned int *lookup_indexes /* OUT */)
 895 {
 896   static_assert ((OT::FeatureVariations::NOT_FOUND_INDEX == HB_OT_LAYOUT_NO_VARIATIONS_INDEX), "");
 897   const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
 898
 899   const OT::Feature &f = g.get_feature_variation (feature_index, variations_index);
 900
 901   return f.get_lookup_indexes (start_offset, lookup_count, lookup_indexes);
 902 }
 903
 904
 905 /*
 906  * OT::GSUB
 907  */
 908
 909 hb_bool_t
 910 hb_ot_layout_has_substitution (hb_face_t *face)
 911 {
 912   return &_get_gsub (face) != &OT::Null(OT::GSUB);
 913 }
 914
 915 /**
 916  * hb_ot_layout_lookup_would_substitute:
 917  *
 918  * Since: 0.9.7
 919  **/
 920 hb_bool_t
 921 hb_ot_layout_lookup_would_substitute (hb_face_t            *face,
 922                                       unsigned int          lookup_index,
 923                                       const hb_codepoint_t *glyphs,
 924                                       unsigned int          glyphs_length,
 925                                       hb_bool_t             zero_context)
 926 {
 927   if (unlikely (!hb_ot_shaper_face_data_ensure (face))) return false;
 928   return hb_ot_layout_lookup_would_substitute_fast (face, lookup_index, glyphs, glyphs_length, zero_context);
 929 }
 930
 931 hb_bool_t
 932 hb_ot_layout_lookup_would_substitute_fast (hb_face_t            *face,
 933                                            unsigned int          lookup_index,
 934                                            const hb_codepoint_t *glyphs,
 935                                            unsigned int          glyphs_length,
 936                                            hb_bool_t             zero_context)
 937 {
 938   if (unlikely (lookup_index >= hb_ot_layout_from_face (face)->gsub_lookup_count)) return false;
 939   OT::hb_would_apply_context_t c (face, glyphs, glyphs_length, (bool) zero_context);
 940
 941   const OT::SubstLookup& l = hb_ot_layout_from_face (face)->gsub->get_lookup (lookup_index);
 942
 943   return l.would_apply (&c, &hb_ot_layout_from_face (face)->gsub_accels[lookup_index]);
 944 }
 945
 946 void
 947 hb_ot_layout_substitute_start (hb_font_t *font, hb_buffer_t *buffer)
 948 {
 949   OT::GSUB::substitute_start (font, buffer);
 950 }
 951
 952 /**
 953  * hb_ot_layout_lookup_substitute_closure:
 954  *
 955  * Since: 0.9.7
 956  **/
 957 void
 958 hb_ot_layout_lookup_substitute_closure (hb_face_t    *face,
 959                                         unsigned int  lookup_index,
 960                                         hb_set_t     *glyphs)
 961 {
 962   OT::hb_closure_context_t c (face, glyphs);
 963
 964   const OT::SubstLookup& l = _get_gsub (face).get_lookup (lookup_index);
 965
 966   l.closure (&c);
 967 }
 968
 969 /*
 970  * OT::GPOS
 971  */
 972
 973 hb_bool_t
 974 hb_ot_layout_has_positioning (hb_face_t *face)
 975 {
 976   return &_get_gpos (face) != &OT::Null(OT::GPOS);
 977 }
 978
 979 void
 980 hb_ot_layout_position_start (hb_font_t *font, hb_buffer_t *buffer)
 981 {
 982   OT::GPOS::position_start (font, buffer);
 983 }
 984
 985 void
 986 hb_ot_layout_position_finish_advances (hb_font_t *font, hb_buffer_t *buffer)
 987 {
 988   OT::GPOS::position_finish_advances (font, buffer);
 989 }
 990
 991 void
 992 hb_ot_layout_position_finish_offsets (hb_font_t *font, hb_buffer_t *buffer)
 993 {
 994   OT::GPOS::position_finish_offsets (font, buffer);
 995 }
 996
 997 /**
 998  * hb_ot_layout_get_size_params:
 999  *
1000  * Since: 0.9.10
1001  **/
1002 hb_bool_t
1003 hb_ot_layout_get_size_params (hb_face_t    *face,
1004                               unsigned int *design_size,       /* OUT.  May be nullptr */
1005                               unsigned int *subfamily_id,      /* OUT.  May be nullptr */
1006                               unsigned int *subfamily_name_id, /* OUT.  May be nullptr */
1007                               unsigned int *range_start,       /* OUT.  May be nullptr */
1008                               unsigned int *range_end          /* OUT.  May be nullptr */)
1009 {
1010   const OT::GPOS &gpos = _get_gpos (face);
1011   const hb_tag_t tag = HB_TAG ('s','i','z','e');
1012
1013   unsigned int num_features = gpos.get_feature_count ();
1014   for (unsigned int i = 0; i < num_features; i++)
1015   {
1016     if (tag == gpos.get_feature_tag (i))
1017     {
1018       const OT::Feature &f = gpos.get_feature (i);
1019       const OT::FeatureParamsSize &params = f.get_feature_params ().get_size_params (tag);
1020
1021       if (params.designSize)
1022       {
1023 #define PARAM(a, A) if (a) *a = params.A
1024         PARAM (design_size, designSize);
1025         PARAM (subfamily_id, subfamilyID);
1026         PARAM (subfamily_name_id, subfamilyNameID);
1027         PARAM (range_start, rangeStart);
1028         PARAM (range_end, rangeEnd);
1029 #undef PARAM
1030
1031         return true;
1032       }
1033     }
1034   }
1035
1036 #define PARAM(a, A) if (a) *a = 0
1037   PARAM (design_size, designSize);
1038   PARAM (subfamily_id, subfamilyID);
1039   PARAM (subfamily_name_id, subfamilyNameID);
1040   PARAM (range_start, rangeStart);
1041   PARAM (range_end, rangeEnd);
1042 #undef PARAM
1043
1044   return false;
1045 }
1046
1047
1048 /*
1049  * Parts of different types are implemented here such that they have direct
1050  * access to GSUB/GPOS lookups.
1051  */
1052
1053
1054 struct GSUBProxy
1055 {
1056   static const unsigned int table_index = 0;
1057   static const bool inplace = false;
1058   typedef OT::SubstLookup Lookup;
1059
1060   GSUBProxy (hb_face_t *face) :
1061     table (*hb_ot_layout_from_face (face)->gsub),
1062     accels (hb_ot_layout_from_face (face)->gsub_accels) {}
1063
1064   const OT::GSUB &table;
1065   const hb_ot_layout_lookup_accelerator_t *accels;
1066 };
1067
1068 struct GPOSProxy
1069 {
1070   static const unsigned int table_index = 1;
1071   static const bool inplace = true;
1072   typedef OT::PosLookup Lookup;
1073
1074   GPOSProxy (hb_face_t *face) :
1075     table (*hb_ot_layout_from_face (face)->gpos),
1076     accels (hb_ot_layout_from_face (face)->gpos_accels) {}
1077
1078   const OT::GPOS &table;
1079   const hb_ot_layout_lookup_accelerator_t *accels;
1080 };
1081
1082
1083 struct hb_get_subtables_context_t :
1084        OT::hb_dispatch_context_t<hb_get_subtables_context_t, hb_void_t, HB_DEBUG_APPLY>
1085 {
1086   template <typename Type>
1087   static inline bool apply_to (const void *obj, OT::hb_ot_apply_context_t *c)
1088   {
1089     const Type *typed_obj = (const Type *) obj;
1090     return typed_obj->apply (c);
1091   }
1092
1093   typedef bool (*hb_apply_func_t) (const void *obj, OT::hb_ot_apply_context_t *c);
1094
1095   struct hb_applicable_t
1096   {
1097     inline void init (const void *obj_, hb_apply_func_t apply_func_)
1098     {
1099       obj = obj_;
1100       apply_func = apply_func_;
1101     }
1102
1103     inline bool apply (OT::hb_ot_apply_context_t *c) const { return apply_func (obj, c); }
1104
1105     private:
1106     const void *obj;
1107     hb_apply_func_t apply_func;
1108   };
1109
1110   typedef hb_auto_array_t<hb_applicable_t> array_t;
1111
1112   /* Dispatch interface. */
1113   inline const char *get_name (void) { return "GET_SUBTABLES"; }
1114   template <typename T>
1115   inline return_t dispatch (const T &obj)
1116   {
1117     hb_applicable_t *entry = array.push();
1118     if (likely (entry))
1119       entry->init (&obj, apply_to<T>);
1120     return HB_VOID;
1121   }
1122   static return_t default_return_value (void) { return HB_VOID; }
1123   bool stop_sublookup_iteration (return_t r HB_UNUSED) const { return false; }
1124
1125   hb_get_subtables_context_t (array_t &array_) :
1126                               array (array_),
1127                               debug_depth (0) {}
1128
1129   array_t &array;
1130   unsigned int debug_depth;
1131 };
1132
1133 static inline bool
1134 apply_forward (OT::hb_ot_apply_context_t *c,
1135                const hb_ot_layout_lookup_accelerator_t &accel,
1136                const hb_get_subtables_context_t::array_t &subtables)
1137 {
1138   bool ret = false;
1139   hb_buffer_t *buffer = c->buffer;
1140   while (buffer->idx < buffer->len && !buffer->in_error)
1141   {
1142     bool applied = false;
1143     if (accel.may_have (buffer->cur().codepoint) &&
1144         (buffer->cur().mask & c->lookup_mask) &&
1145         c->check_glyph_property (&buffer->cur(), c->lookup_props))
1146      {
1147        for (unsigned int i = 0; i < subtables.len; i++)
1148          if (subtables[i].apply (c))
1149          {
1150            applied = true;
1151            break;
1152          }
1153      }
1154
1155     if (applied)
1156       ret = true;
1157     else
1158       buffer->next_glyph ();
1159   }
1160   return ret;
1161 }
1162
1163 static inline bool
1164 apply_backward (OT::hb_ot_apply_context_t *c,
1165                const hb_ot_layout_lookup_accelerator_t &accel,
1166                const hb_get_subtables_context_t::array_t &subtables)
1167 {
1168   bool ret = false;
1169   hb_buffer_t *buffer = c->buffer;
1170   do
1171   {
1172     if (accel.may_have (buffer->cur().codepoint) &&
1173         (buffer->cur().mask & c->lookup_mask) &&
1174         c->check_glyph_property (&buffer->cur(), c->lookup_props))
1175     {
1176      for (unsigned int i = 0; i < subtables.len; i++)
1177        if (subtables[i].apply (c))
1178        {
1179          ret = true;
1180          break;
1181        }
1182     }
1183     /* The reverse lookup doesn't "advance" cursor (for good reason). */
1184     buffer->idx--;
1185
1186   }
1187   while ((int) buffer->idx >= 0);
1188   return ret;
1189 }
1190
1191 template <typename Proxy>
1192 static inline void
1193 apply_string (OT::hb_ot_apply_context_t *c,
1194               const typename Proxy::Lookup &lookup,
1195               const hb_ot_layout_lookup_accelerator_t &accel)
1196 {
1197   hb_buffer_t *buffer = c->buffer;
1198
1199   if (unlikely (!buffer->len || !c->lookup_mask))
1200     return;
1201
1202   c->set_lookup_props (lookup.get_props ());
1203
1204   hb_get_subtables_context_t::array_t subtables;
1205   hb_get_subtables_context_t c_get_subtables (subtables);
1206   lookup.dispatch (&c_get_subtables);
1207
1208   if (likely (!lookup.is_reverse ()))
1209   {
1210     /* in/out forward substitution/positioning */
1211     if (Proxy::table_index == 0)
1212       buffer->clear_output ();
1213     buffer->idx = 0;
1214
1215     bool ret;
1216     ret = apply_forward (c, accel, subtables);
1217     if (ret)
1218     {
1219       if (!Proxy::inplace)
1220         buffer->swap_buffers ();
1221       else
1222         assert (!buffer->has_separate_output ());
1223     }
1224   }
1225   else
1226   {
1227     /* in-place backward substitution/positioning */
1228     if (Proxy::table_index == 0)
1229       buffer->remove_output ();
1230     buffer->idx = buffer->len - 1;
1231
1232     apply_backward (c, accel, subtables);
1233   }
1234 }
1235
1236 template <typename Proxy>
1237 inline void hb_ot_map_t::apply (const Proxy &proxy,
1238                                 const hb_ot_shape_plan_t *plan,
1239                                 hb_font_t *font,
1240                                 hb_buffer_t *buffer) const
1241 {
1242   const unsigned int table_index = proxy.table_index;
1243   unsigned int i = 0;
1244   OT::hb_ot_apply_context_t c (table_index, font, buffer);
1245   c.set_recurse_func (Proxy::Lookup::apply_recurse_func);
1246
1247   for (unsigned int stage_index = 0; stage_index < stages[table_index].len; stage_index++) {
1248     const stage_map_t *stage = &stages[table_index][stage_index];
1249     for (; i < stage->last_lookup; i++)
1250     {
1251       unsigned int lookup_index = lookups[table_index][i].index;
1252       if (!buffer->message (font, "start lookup %d", lookup_index)) continue;
1253       c.set_lookup_index (lookup_index);
1254       c.set_lookup_mask (lookups[table_index][i].mask);
1255       c.set_auto_zwj (lookups[table_index][i].auto_zwj);
1256       c.set_auto_zwnj (lookups[table_index][i].auto_zwnj);
1257       apply_string<Proxy> (&c,
1258                            proxy.table.get_lookup (lookup_index),
1259                            proxy.accels[lookup_index]);
1260       (void) buffer->message (font, "end lookup %d", lookup_index);
1261     }
1262
1263     if (stage->pause_func)
1264     {
1265       buffer->clear_output ();
1266       stage->pause_func (plan, font, buffer);
1267     }
1268   }
1269 }
1270
1271 void hb_ot_map_t::substitute (const hb_ot_shape_plan_t *plan, hb_font_t *font, hb_buffer_t *buffer) const
1272 {
1273   GSUBProxy proxy (font->face);
1274   apply (proxy, plan, font, buffer);
1275 }
1276
1277 void hb_ot_map_t::position (const hb_ot_shape_plan_t *plan, hb_font_t *font, hb_buffer_t *buffer) const
1278 {
1279   GPOSProxy proxy (font->face);
1280   apply (proxy, plan, font, buffer);
1281 }
1282
1283 void
1284 hb_ot_layout_substitute_lookup (OT::hb_ot_apply_context_t *c,
1285                                 const OT::SubstLookup &lookup,
1286                                 const hb_ot_layout_lookup_accelerator_t &accel)
1287 {
1288   apply_string<GSUBProxy> (c, lookup, accel);
1289 }
1290
1291
1292
1293
1294 /*
1295  * OT::BASE
1296  */
1297
1298 // /**
1299 //  * hb_ot_base_has_data:
1300 //  * @face: #hb_face_t to test
1301 //  *
1302 //  * This function allows to verify the presence of an OpenType BASE table on the
1303 //  * face.
1304 //  *
1305 //  * Return value: true if face has a BASE table, false otherwise
1306 //  *
1307 //  * Since: XXX
1308 //  **/
1309 // hb_bool_t
1310 // hb_ot_base_has_data (hb_face_t *face)
1311 // {
1312 //   return &_get_base (face) != &OT::Null(OT::BASE);
1313 // }