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