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