harfbuzz/src/hb-aat-layout.cc

/*
 * Copyright © 2017  Google, Inc.
 * Copyright © 2018  Ebrahim Byagowi
 *
 *  This is part of HarfBuzz, a text shaping library.
 *
 * Permission is hereby granted, without written agreement and without
 * license or royalty fees, to use, copy, modify, and distribute this
 * software and its documentation for any purpose, provided that the
 * above copyright notice and the following two paragraphs appear in
 * all copies of this software.
 *
 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 *
 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
 *
 * Google Author(s): Behdad Esfahbod
 */

#include "hb-open-type.hh"

#include "hb-ot-face.hh"
#include "hb-aat.h"
#include "hb-aat-layout.hh"
#include "hb-aat-layout-ankr-table.hh"
#include "hb-aat-layout-bsln-table.hh" // Just so we compile it; unused otherwise.
#include "hb-aat-layout-feat-table.hh" // Just so we compile it; unused otherwise.
#include "hb-aat-layout-just-table.hh" // Just so we compile it; unused otherwise.
#include "hb-aat-layout-kerx-table.hh"
#include "hb-aat-layout-morx-table.hh"
#include "hb-aat-layout-trak-table.hh"
#include "hb-aat-ltag-table.hh"


/* Table data courtesy of Apple.  Converted from mnemonics to integers
 * when moving to this file. */
static const hb_aat_feature_mapping_t feature_mappings[] =
{
  {HB_TAG ('a','f','r','c'),   HB_AAT_LAYOUT_FEATURE_TYPE_FRACTIONS,               1/*kVerticalFractionsSelector*/,             0/*kNoFractionsSelector*/},
  {HB_TAG ('c','2','p','c'),   HB_AAT_LAYOUT_FEATURE_TYPE_UPPER_CASE,              2/*kUpperCasePetiteCapsSelector*/,           0/*kDefaultUpperCaseSelector*/},
  {HB_TAG ('c','2','s','c'),   HB_AAT_LAYOUT_FEATURE_TYPE_UPPER_CASE,              1/*kUpperCaseSmallCapsSelector*/,            0/*kDefaultUpperCaseSelector*/},
  {HB_TAG ('c','a','l','t'),   HB_AAT_LAYOUT_FEATURE_TYPE_CONTEXTUAL_ALTERNATIVES, 0/*kContextualAlternatesOnSelector*/,        1/*kContextualAlternatesOffSelector*/},
  {HB_TAG ('c','a','s','e'),   HB_AAT_LAYOUT_FEATURE_TYPE_CASE_SENSITIVE_LAYOUT,   0/*kCaseSensitiveLayoutOnSelector*/,         1/*kCaseSensitiveLayoutOffSelector*/},
  {HB_TAG ('c','l','i','g'),   HB_AAT_LAYOUT_FEATURE_TYPE_LIGATURES,               18/*kContextualLigaturesOnSelector*/,        19/*kContextualLigaturesOffSelector*/},
  {HB_TAG ('c','p','s','p'),   HB_AAT_LAYOUT_FEATURE_TYPE_CASE_SENSITIVE_LAYOUT,   2/*kCaseSensitiveSpacingOnSelector*/,        3/*kCaseSensitiveSpacingOffSelector*/},
  {HB_TAG ('c','s','w','h'),   HB_AAT_LAYOUT_FEATURE_TYPE_CONTEXTUAL_ALTERNATIVES, 4/*kContextualSwashAlternatesOnSelector*/,   5/*kContextualSwashAlternatesOffSelector*/},
  {HB_TAG ('d','l','i','g'),   HB_AAT_LAYOUT_FEATURE_TYPE_LIGATURES,               4/*kRareLigaturesOnSelector*/,               5/*kRareLigaturesOffSelector*/},
  {HB_TAG ('e','x','p','t'),   HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_SHAPE,         10/*kExpertCharactersSelector*/,             16},
  {HB_TAG ('f','r','a','c'),   HB_AAT_LAYOUT_FEATURE_TYPE_FRACTIONS,               2/*kDiagonalFractionsSelector*/,             0/*kNoFractionsSelector*/},
  {HB_TAG ('f','w','i','d'),   HB_AAT_LAYOUT_FEATURE_TYPE_TEXT_SPACING,            1/*kMonospacedTextSelector*/,                7},
  {HB_TAG ('h','a','l','t'),   HB_AAT_LAYOUT_FEATURE_TYPE_TEXT_SPACING,            6/*kAltHalfWidthTextSelector*/,              7},
  {HB_TAG ('h','i','s','t'),   HB_AAT_LAYOUT_FEATURE_TYPE_LIGATURES,               20/*kHistoricalLigaturesOnSelector*/,        21/*kHistoricalLigaturesOffSelector*/},
  {HB_TAG ('h','k','n','a'),   HB_AAT_LAYOUT_FEATURE_TYPE_ALTERNATE_KANA,          0/*kAlternateHorizKanaOnSelector*/,          1/*kAlternateHorizKanaOffSelector*/,        },
  {HB_TAG ('h','l','i','g'),   HB_AAT_LAYOUT_FEATURE_TYPE_LIGATURES,               20/*kHistoricalLigaturesOnSelector*/,        21/*kHistoricalLigaturesOffSelector*/},
  {HB_TAG ('h','n','g','l'),   HB_AAT_LAYOUT_FEATURE_TYPE_TRANSLITERATION,         1/*kHanjaToHangulSelector*/,                 0/*kNoTransliterationSelector*/},
  {HB_TAG ('h','o','j','o'),   HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_SHAPE,         12/*kHojoCharactersSelector*/,               16},
  {HB_TAG ('h','w','i','d'),   HB_AAT_LAYOUT_FEATURE_TYPE_TEXT_SPACING,            2/*kHalfWidthTextSelector*/,                 7},
  {HB_TAG ('i','t','a','l'),   HB_AAT_LAYOUT_FEATURE_TYPE_ITALIC_CJK_ROMAN,        2/*kCJKItalicRomanOnSelector*/,              3/*kCJKItalicRomanOffSelector*/},
  {HB_TAG ('j','p','0','4'),   HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_SHAPE,         11/*kJIS2004CharactersSelector*/,            16},
  {HB_TAG ('j','p','7','8'),   HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_SHAPE,         2/*kJIS1978CharactersSelector*/,             16},
  {HB_TAG ('j','p','8','3'),   HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_SHAPE,         3/*kJIS1983CharactersSelector*/,             16},
  {HB_TAG ('j','p','9','0'),   HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_SHAPE,         4/*kJIS1990CharactersSelector*/,             16},
  {HB_TAG ('l','i','g','a'),   HB_AAT_LAYOUT_FEATURE_TYPE_LIGATURES,               2/*kCommonLigaturesOnSelector*/,             3/*kCommonLigaturesOffSelector*/},
  {HB_TAG ('l','n','u','m'),   HB_AAT_LAYOUT_FEATURE_TYPE_NUMBER_CASE,             1/*kUpperCaseNumbersSelector*/,              2},
  {HB_TAG ('m','g','r','k'),   HB_AAT_LAYOUT_FEATURE_TYPE_MATHEMATICAL_EXTRAS,     10/*kMathematicalGreekOnSelector*/,          11/*kMathematicalGreekOffSelector*/},
  {HB_TAG ('n','l','c','k'),   HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_SHAPE,         13/*kNLCCharactersSelector*/,                16},
  {HB_TAG ('o','n','u','m'),   HB_AAT_LAYOUT_FEATURE_TYPE_NUMBER_CASE,             0/*kLowerCaseNumbersSelector*/,              2},
  {HB_TAG ('o','r','d','n'),   HB_AAT_LAYOUT_FEATURE_TYPE_VERTICAL_POSITION,       3/*kOrdinalsSelector*/,                      0/*kNormalPositionSelector*/},
  {HB_TAG ('p','a','l','t'),   HB_AAT_LAYOUT_FEATURE_TYPE_TEXT_SPACING,            5/*kAltProportionalTextSelector*/,           7},
  {HB_TAG ('p','c','a','p'),   HB_AAT_LAYOUT_FEATURE_TYPE_LOWER_CASE,              2/*kLowerCasePetiteCapsSelector*/,           0/*kDefaultLowerCaseSelector*/},
  {HB_TAG ('p','k','n','a'),   HB_AAT_LAYOUT_FEATURE_TYPE_TEXT_SPACING,            0/*kProportionalTextSelector*/,              7},
  {HB_TAG ('p','n','u','m'),   HB_AAT_LAYOUT_FEATURE_TYPE_NUMBER_SPACING,          1/*kProportionalNumbersSelector*/,           4},
  {HB_TAG ('p','w','i','d'),   HB_AAT_LAYOUT_FEATURE_TYPE_TEXT_SPACING,            0/*kProportionalTextSelector*/,              7},
  {HB_TAG ('q','w','i','d'),   HB_AAT_LAYOUT_FEATURE_TYPE_TEXT_SPACING,            4/*kQuarterWidthTextSelector*/,              7},
  {HB_TAG ('r','u','b','y'),   HB_AAT_LAYOUT_FEATURE_TYPE_RUBYKANA,                2/*kRubyKanaOnSelector*/,                    3/*kRubyKanaOffSelector*/},
  {HB_TAG ('s','i','n','f'),   HB_AAT_LAYOUT_FEATURE_TYPE_VERTICAL_POSITION,       4/*kScientificInferiorsSelector*/,           0/*kNormalPositionSelector*/},
  {HB_TAG ('s','m','c','p'),   HB_AAT_LAYOUT_FEATURE_TYPE_LOWER_CASE,              1/*kLowerCaseSmallCapsSelector*/,            0/*kDefaultLowerCaseSelector*/},
  {HB_TAG ('s','m','p','l'),   HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_SHAPE,         1/*kSimplifiedCharactersSelector*/,          16},
  {HB_TAG ('s','s','0','1'),   HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES,  2/*kStylisticAltOneOnSelector*/,             3/*kStylisticAltOneOffSelector*/},
  {HB_TAG ('s','s','0','2'),   HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES,  4/*kStylisticAltTwoOnSelector*/,             5/*kStylisticAltTwoOffSelector*/},
  {HB_TAG ('s','s','0','3'),   HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES,  6/*kStylisticAltThreeOnSelector*/,           7/*kStylisticAltThreeOffSelector*/},
  {HB_TAG ('s','s','0','4'),   HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES,  8/*kStylisticAltFourOnSelector*/,            9/*kStylisticAltFourOffSelector*/},
  {HB_TAG ('s','s','0','5'),   HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES,  10/*kStylisticAltFiveOnSelector*/,           11/*kStylisticAltFiveOffSelector*/},
  {HB_TAG ('s','s','0','6'),   HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES,  12/*kStylisticAltSixOnSelector*/,            13/*kStylisticAltSixOffSelector*/},
  {HB_TAG ('s','s','0','7'),   HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES,  14/*kStylisticAltSevenOnSelector*/,          15/*kStylisticAltSevenOffSelector*/},
  {HB_TAG ('s','s','0','8'),   HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES,  16/*kStylisticAltEightOnSelector*/,          17/*kStylisticAltEightOffSelector*/},
  {HB_TAG ('s','s','0','9'),   HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES,  18/*kStylisticAltNineOnSelector*/,           19/*kStylisticAltNineOffSelector*/},
  {HB_TAG ('s','s','1','0'),   HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES,  20/*kStylisticAltTenOnSelector*/,            21/*kStylisticAltTenOffSelector*/},
  {HB_TAG ('s','s','1','1'),   HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES,  22/*kStylisticAltElevenOnSelector*/,         23/*kStylisticAltElevenOffSelector*/},
  {HB_TAG ('s','s','1','2'),   HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES,  24/*kStylisticAltTwelveOnSelector*/,         25/*kStylisticAltTwelveOffSelector*/},
  {HB_TAG ('s','s','1','3'),   HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES,  26/*kStylisticAltThirteenOnSelector*/,       27/*kStylisticAltThirteenOffSelector*/},
  {HB_TAG ('s','s','1','4'),   HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES,  28/*kStylisticAltFourteenOnSelector*/,       29/*kStylisticAltFourteenOffSelector*/},
  {HB_TAG ('s','s','1','5'),   HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES,  30/*kStylisticAltFifteenOnSelector*/,        31/*kStylisticAltFifteenOffSelector*/},
  {HB_TAG ('s','s','1','6'),   HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES,  32/*kStylisticAltSixteenOnSelector*/,        33/*kStylisticAltSixteenOffSelector*/},
  {HB_TAG ('s','s','1','7'),   HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES,  34/*kStylisticAltSeventeenOnSelector*/,      35/*kStylisticAltSeventeenOffSelector*/},
  {HB_TAG ('s','s','1','8'),   HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES,  36/*kStylisticAltEighteenOnSelector*/,       37/*kStylisticAltEighteenOffSelector*/},
  {HB_TAG ('s','s','1','9'),   HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES,  38/*kStylisticAltNineteenOnSelector*/,       39/*kStylisticAltNineteenOffSelector*/},
  {HB_TAG ('s','s','2','0'),   HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES,  40/*kStylisticAltTwentyOnSelector*/,         41/*kStylisticAltTwentyOffSelector*/},
  {HB_TAG ('s','u','b','s'),   HB_AAT_LAYOUT_FEATURE_TYPE_VERTICAL_POSITION,       2/*kInferiorsSelector*/,                     0/*kNormalPositionSelector*/},
  {HB_TAG ('s','u','p','s'),   HB_AAT_LAYOUT_FEATURE_TYPE_VERTICAL_POSITION,       1/*kSuperiorsSelector*/,                     0/*kNormalPositionSelector*/},
  {HB_TAG ('s','w','s','h'),   HB_AAT_LAYOUT_FEATURE_TYPE_CONTEXTUAL_ALTERNATIVES, 2/*kSwashAlternatesOnSelector*/,             3/*kSwashAlternatesOffSelector*/},
  {HB_TAG ('t','i','t','l'),   HB_AAT_LAYOUT_FEATURE_TYPE_STYLE_OPTIONS,           4/*kTitlingCapsSelector*/,                   0/*kNoStyleOptionsSelector*/},
  {HB_TAG ('t','n','a','m'),   HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_SHAPE,         14/*kTraditionalNamesCharactersSelector*/,   16},
  {HB_TAG ('t','n','u','m'),   HB_AAT_LAYOUT_FEATURE_TYPE_NUMBER_SPACING,          0/*kMonospacedNumbersSelector*/,             4},
  {HB_TAG ('t','r','a','d'),   HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_SHAPE,         0/*kTraditionalCharactersSelector*/,         16},
  {HB_TAG ('t','w','i','d'),   HB_AAT_LAYOUT_FEATURE_TYPE_TEXT_SPACING,            3/*kThirdWidthTextSelector*/,                7},
  {HB_TAG ('u','n','i','c'),   HB_AAT_LAYOUT_FEATURE_TYPE_LETTER_CASE,             14,                                          15},
  {HB_TAG ('v','a','l','t'),   HB_AAT_LAYOUT_FEATURE_TYPE_TEXT_SPACING,            5/*kAltProportionalTextSelector*/,           7},
  {HB_TAG ('v','e','r','t'),   HB_AAT_LAYOUT_FEATURE_TYPE_VERTICAL_SUBSTITUTION,   0/*kSubstituteVerticalFormsOnSelector*/,     1/*kSubstituteVerticalFormsOffSelector*/},
  {HB_TAG ('v','h','a','l'),   HB_AAT_LAYOUT_FEATURE_TYPE_TEXT_SPACING,            6/*kAltHalfWidthTextSelector*/,              7},
  {HB_TAG ('v','k','n','a'),   HB_AAT_LAYOUT_FEATURE_TYPE_ALTERNATE_KANA,          2/*kAlternateVertKanaOnSelector*/,           3/*kAlternateVertKanaOffSelector*/},
  {HB_TAG ('v','p','a','l'),   HB_AAT_LAYOUT_FEATURE_TYPE_TEXT_SPACING,            5/*kAltProportionalTextSelector*/,           7},
  {HB_TAG ('v','r','t','2'),   HB_AAT_LAYOUT_FEATURE_TYPE_VERTICAL_SUBSTITUTION,   0/*kSubstituteVerticalFormsOnSelector*/,     1/*kSubstituteVerticalFormsOffSelector*/},
  {HB_TAG ('z','e','r','o'),   HB_AAT_LAYOUT_FEATURE_TYPE_TYPOGRAPHIC_EXTRAS,      4/*kSlashedZeroOnSelector*/,                 5/*kSlashedZeroOffSelector*/},
};

const hb_aat_feature_mapping_t *
hb_aat_layout_find_feature_mapping (hb_tag_t tag)
{
  return (const hb_aat_feature_mapping_t *) bsearch (&tag,
						     feature_mappings,
						     ARRAY_LENGTH (feature_mappings),
						     sizeof (feature_mappings[0]),
						     hb_aat_feature_mapping_t::cmp);
}


/*
 * hb_aat_apply_context_t
 */

AAT::hb_aat_apply_context_t::hb_aat_apply_context_t (const hb_ot_shape_plan_t *plan_,
						     hb_font_t *font_,
						     hb_buffer_t *buffer_,
						     hb_blob_t *blob) :
						       plan (plan_),
						       font (font_),
						       face (font->face),
						       buffer (buffer_),
						       sanitizer (),
						       ankr_table (&Null(AAT::ankr)),
						       ankr_end (nullptr),
						       lookup_index (0),
						       debug_depth (0)
{
  sanitizer.init (blob);
  sanitizer.set_num_glyphs (face->get_num_glyphs ());
  sanitizer.start_processing ();
  sanitizer.set_max_ops (HB_SANITIZE_MAX_OPS_MAX);
}

AAT::hb_aat_apply_context_t::~hb_aat_apply_context_t (void)
{
  sanitizer.end_processing ();
}

void
AAT::hb_aat_apply_context_t::set_ankr_table (const AAT::ankr *ankr_table_,
					     const char      *ankr_end_)
{
  ankr_table = ankr_table_;
  ankr_end = ankr_end_;
}


/*
 * mort/morx/kerx/trak
 */


void
hb_aat_layout_compile_map (const hb_aat_map_builder_t *mapper,
			   hb_aat_map_t *map)
{
  const AAT::morx& morx = *mapper->face->table.morx;
  if (morx.has_data ())
  {
    morx.compile_flags (mapper, map);
    return;
  }

  const AAT::mort& mort = *mapper->face->table.mort;
  if (mort.has_data ())
  {
    mort.compile_flags (mapper, map);
    return;
  }
}


bool
hb_aat_layout_has_substitution (hb_face_t *face)
{
  return face->table.morx->has_data () ||
	 face->table.mort->has_data ();
}

void
hb_aat_layout_substitute (const hb_ot_shape_plan_t *plan,
			  hb_font_t *font,
			  hb_buffer_t *buffer)
{
  hb_blob_t *morx_blob = font->face->table.morx.get_blob ();
  const AAT::morx& morx = *morx_blob->as<AAT::morx> ();
  if (morx.has_data ())
  {
    AAT::hb_aat_apply_context_t c (plan, font, buffer, morx_blob);
    morx.apply (&c);
    return;
  }

  hb_blob_t *mort_blob = font->face->table.mort.get_blob ();
  const AAT::mort& mort = *mort_blob->as<AAT::mort> ();
  if (mort.has_data ())
  {
    AAT::hb_aat_apply_context_t c (plan, font, buffer, mort_blob);
    mort.apply (&c);
    return;
  }
}

void
hb_aat_layout_zero_width_deleted_glyphs (hb_buffer_t *buffer)
{
  unsigned int count = buffer->len;
  hb_glyph_info_t *info = buffer->info;
  hb_glyph_position_t *pos = buffer->pos;
  for (unsigned int i = 0; i < count; i++)
    if (unlikely (info[i].codepoint == AAT::DELETED_GLYPH))
      pos[i].x_advance = pos[i].y_advance = pos[i].x_offset = pos[i].y_offset = 0;
}

static bool
is_deleted_glyph (const hb_glyph_info_t *info)
{
  return info->codepoint == AAT::DELETED_GLYPH;
}

void
hb_aat_layout_remove_deleted_glyphs (hb_buffer_t *buffer)
{
  hb_ot_layout_delete_glyphs_inplace (buffer, is_deleted_glyph);
}



bool
hb_aat_layout_has_positioning (hb_face_t *face)
{
  return face->table.kerx->has_data ();
}

void
hb_aat_layout_position (const hb_ot_shape_plan_t *plan,
			hb_font_t *font,
			hb_buffer_t *buffer)
{
  hb_blob_t *kerx_blob = font->face->table.kerx.get_blob ();
  const AAT::kerx& kerx = *kerx_blob->as<AAT::kerx> ();

  hb_blob_t *ankr_blob = font->face->table.ankr.get_blob ();;
  const AAT::ankr& ankr = *font->face->table.ankr;

  AAT::hb_aat_apply_context_t c (plan, font, buffer, kerx_blob);
  c.set_ankr_table (&ankr, ankr_blob->data + ankr_blob->length);
  kerx.apply (&c);
}


bool
hb_aat_layout_has_tracking (hb_face_t *face)
{
  return face->table.trak->has_data ();
}

void
hb_aat_layout_track (const hb_ot_shape_plan_t *plan,
		     hb_font_t *font,
		     hb_buffer_t *buffer)
{
  const AAT::trak& trak = *font->face->table.trak;

  AAT::hb_aat_apply_context_t c (plan, font, buffer);
  trak.apply (&c);
}


hb_language_t
_hb_aat_language_get (hb_face_t *face,
		      unsigned int i)
{
  return face->table.ltag->get_language (i);
}

/**
 * hb_aat_layout_get_feature_settings:
 * @face:            a font face.
 * @feature:         AAT feature id you are querying.
 * @default_setting: (out): default value for the type. If it is HB_AAT_LAYOUT_FEATURE_TYPE_UNDEFINED
 *                          means none is selected as default and the feature is not exclusive.
 * @start_offset:    start offset, if you are iterating
 * @selectors_count: (inout): gets input buffer size, puts number of filled one
 * @selectors_buffer:  (out):  buffer of records
 *
 * Returns: Total number of feature selector records available for the feature.
 *
 * Since: REPLACEME
 */
unsigned int
hb_aat_layout_get_feature_settings (hb_face_t                             *face,
				    hb_aat_layout_feature_type_t           feature,
				    hb_aat_layout_feature_setting_t       *default_setting, /* OUT.     May be NULL. */
				    unsigned int                           start_offset,
				    unsigned int                          *selectors_count, /* IN/OUT.  May be NULL. */
				    hb_aat_layout_feature_type_selector_t *selectors_buffer /* OUT.     May be NULL. */)
{
  return face->table.feat->get_settings (feature, default_setting,
					 start_offset, selectors_count, selectors_buffer);
}


unsigned int
hb_aat_layout_get_features (hb_face_t                      *face,
			    unsigned int                    start_offset,
			    unsigned int                   *record_count, /* IN/OUT.  May be NULL. */
			    hb_aat_layout_feature_record_t *record_buffer /* OUT.     May be NULL. */)
{
  return face->table.feat->get_features (start_offset, record_count, record_buffer);
}