tor-browser

hb-ot-layout-base-table.hh (26957B)

---

/*
* Copyright © 2016  Elie Roux <elie.roux@telecom-bretagne.eu>
* Copyright © 2018  Google, Inc.
* Copyright © 2018-2019  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
*/

#ifndef HB_OT_LAYOUT_BASE_TABLE_HH
#define HB_OT_LAYOUT_BASE_TABLE_HH

#include "hb-open-type.hh"
#include "hb-ot-layout-common.hh"

namespace OT {

/*
* BASE -- Baseline
* https://docs.microsoft.com/en-us/typography/opentype/spec/base
*/

struct BaseCoordFormat1
{
 hb_position_t get_coord (hb_font_t *font, hb_direction_t direction) const
 {
   return HB_DIRECTION_IS_HORIZONTAL (direction) ? font->em_scale_y (coordinate) : font->em_scale_x (coordinate);
 }

 bool subset (hb_subset_context_t *c) const
 {
   TRACE_SUBSET (this);
   return_trace ((bool) c->serializer->embed (*this));
 }

 bool sanitize (hb_sanitize_context_t *c) const
 {
   TRACE_SANITIZE (this);
   return_trace (c->check_struct (this));
 }

 protected:
 HBUINT16	format;		/* Format identifier--format = 1 */
 FWORD		coordinate;	/* X or Y value, in design units */
 public:
 DEFINE_SIZE_STATIC (4);
};

struct BaseCoordFormat2
{
 hb_position_t get_coord (hb_font_t *font, hb_direction_t direction) const
 {
   /* TODO */
   return HB_DIRECTION_IS_HORIZONTAL (direction) ? font->em_scale_y (coordinate) : font->em_scale_x (coordinate);
 }

 bool subset (hb_subset_context_t *c) const
 {
   TRACE_SUBSET (this);
   auto *out = c->serializer->embed (*this);
   if (unlikely (!out)) return_trace (false);

   return_trace (c->serializer->check_assign (out->referenceGlyph,
                                              c->plan->glyph_map->get (referenceGlyph),
                                              HB_SERIALIZE_ERROR_INT_OVERFLOW));
 }

 bool sanitize (hb_sanitize_context_t *c) const
 {
   TRACE_SANITIZE (this);
   return_trace (c->check_struct (this));
 }

 protected:
 HBUINT16	format;		/* Format identifier--format = 2 */
 FWORD		coordinate;	/* X or Y value, in design units */
 HBGlyphID16	referenceGlyph;	/* Glyph ID of control glyph */
 HBUINT16	coordPoint;	/* Index of contour point on the
			 * reference glyph */
 public:
 DEFINE_SIZE_STATIC (8);
};

struct BaseCoordFormat3
{
 hb_position_t get_coord (hb_font_t *font,
		   const ItemVariationStore &var_store,
		   hb_direction_t direction) const
 {
   const Device &device = this+deviceTable;

   return HB_DIRECTION_IS_HORIZONTAL (direction)
 ? font->em_scale_y (coordinate) + device.get_y_delta (font, var_store)
 : font->em_scale_x (coordinate) + device.get_x_delta (font, var_store);
 }

 void collect_variation_indices (hb_set_t& varidx_set /* OUT */) const
 {
   unsigned varidx = (this+deviceTable).get_variation_index ();
   varidx_set.add (varidx);
 }

 bool subset (hb_subset_context_t *c) const
 {
   TRACE_SUBSET (this);
   auto *out = c->serializer->embed (*this);
   if (unlikely (!out)) return_trace (false);

   if (!c->plan->pinned_at_default)
   {
     unsigned var_idx = (this+deviceTable).get_variation_index ();
     if (var_idx != VarIdx::NO_VARIATION)
     {
       hb_pair_t<unsigned, int> *v;
       if (!c->plan->base_variation_idx_map.has (var_idx, &v))
         return_trace (false);
       
       if (unlikely (!c->serializer->check_assign (out->coordinate, coordinate + hb_second (*v),
                                                   HB_SERIALIZE_ERROR_INT_OVERFLOW)))
         return_trace (false);
     }
   }
   return_trace (out->deviceTable.serialize_copy (c->serializer, deviceTable,
                                                  this, 0,
                                                  hb_serialize_context_t::Head,
                                                  &c->plan->base_variation_idx_map));
 }

 bool sanitize (hb_sanitize_context_t *c) const
 {
   TRACE_SANITIZE (this);
   return_trace (likely (c->check_struct (this) &&
		  deviceTable.sanitize (c, this)));
 }

 protected:
 HBUINT16	format;		/* Format identifier--format = 3 */
 FWORD		coordinate;	/* X or Y value, in design units */
 Offset16To<Device>
	deviceTable;	/* Offset to Device table for X or
			 * Y value, from beginning of
			 * BaseCoord table (may be NULL). */
 public:
 DEFINE_SIZE_STATIC (6);
};

struct BaseCoord
{
 bool has_data () const { return u.format.v; }

 hb_position_t get_coord (hb_font_t            *font,
		   const ItemVariationStore &var_store,
		   hb_direction_t        direction) const
 {
   switch (u.format.v) {
   case 1: hb_barrier (); return u.format1.get_coord (font, direction);
   case 2: hb_barrier (); return u.format2.get_coord (font, direction);
   case 3: hb_barrier (); return u.format3.get_coord (font, var_store, direction);
   default:return 0;
   }
 }

 void collect_variation_indices (hb_set_t& varidx_set /* OUT */) const
 {
   switch (u.format.v) {
   case 3: hb_barrier (); u.format3.collect_variation_indices (varidx_set); return;
   default:return;
   }
 }

 template <typename context_t, typename ...Ts>
 typename context_t::return_t dispatch (context_t *c, Ts&&... ds) const
 {
   if (unlikely (!c->may_dispatch (this, &u.format.v))) return c->no_dispatch_return_value ();
   TRACE_DISPATCH (this, u.format.v);
   switch (u.format.v) {
   case 1: hb_barrier (); return_trace (c->dispatch (u.format1, std::forward<Ts> (ds)...));
   case 2: hb_barrier (); return_trace (c->dispatch (u.format2, std::forward<Ts> (ds)...));
   case 3: hb_barrier (); return_trace (c->dispatch (u.format3, std::forward<Ts> (ds)...));
   default:return_trace (c->default_return_value ());
   }
 }

 bool sanitize (hb_sanitize_context_t *c) const
 {
   TRACE_SANITIZE (this);
   if (unlikely (!u.format.v.sanitize (c))) return_trace (false);
   hb_barrier ();
   switch (u.format.v) {
   case 1: hb_barrier (); return_trace (u.format1.sanitize (c));
   case 2: hb_barrier (); return_trace (u.format2.sanitize (c));
   case 3: hb_barrier (); return_trace (u.format3.sanitize (c));
   default:return_trace (false);
   }
 }

 protected:
 union {
 struct { HBUINT16 v; }	format;
 BaseCoordFormat1	format1;
 BaseCoordFormat2	format2;
 BaseCoordFormat3	format3;
 } u;
 public:
 DEFINE_SIZE_UNION (2, format.v);
};

struct FeatMinMaxRecord
{
 int cmp (hb_tag_t key) const { return tag.cmp (key); }

 bool has_data () const { return tag; }

 hb_tag_t get_feature_tag () const { return tag; }

 void get_min_max (const BaseCoord **min, const BaseCoord **max) const
 {
   if (likely (min)) *min = &(this+minCoord);
   if (likely (max)) *max = &(this+maxCoord);
 }

 void collect_variation_indices (const hb_subset_plan_t* plan,
                                 const void *base,
                                 hb_set_t& varidx_set /* OUT */) const
 {
   if (!plan->layout_features.has (tag))
     return;

   (base+minCoord).collect_variation_indices (varidx_set);
   (base+maxCoord).collect_variation_indices (varidx_set);
 }

 bool subset (hb_subset_context_t *c,
              const void *base) const
 {
   TRACE_SUBSET (this);
   auto *out = c->serializer->embed (*this);
   if (unlikely (!out)) return_trace (false);
   if (!(out->minCoord.serialize_subset (c, minCoord, base)))
     return_trace (false);

   return_trace (out->maxCoord.serialize_subset (c, maxCoord, base));
 }

 bool sanitize (hb_sanitize_context_t *c, const void *base) const
 {
   TRACE_SANITIZE (this);
   return_trace (likely (c->check_struct (this) &&
		  minCoord.sanitize (c, base) &&
		  maxCoord.sanitize (c, base)));
 }

 protected:
 Tag		tag;		/* 4-byte feature identification tag--must
			 * match feature tag in FeatureList */
 Offset16To<BaseCoord>
	minCoord;	/* Offset to BaseCoord table that defines
			 * the minimum extent value, from beginning
			 * of MinMax table (may be NULL) */
 Offset16To<BaseCoord>
	maxCoord;	/* Offset to BaseCoord table that defines
			 * the maximum extent value, from beginning
			 * of MinMax table (may be NULL) */
 public:
 DEFINE_SIZE_STATIC (8);
};

struct MinMax
{
 void get_min_max (hb_tag_t          feature_tag,
	    const BaseCoord **min,
	    const BaseCoord **max) const
 {
   const FeatMinMaxRecord &minMaxCoord = featMinMaxRecords.bsearch (feature_tag);
   if (minMaxCoord.has_data ())
     minMaxCoord.get_min_max (min, max);
   else
   {
     if (likely (min)) *min = &(this+minCoord);
     if (likely (max)) *max = &(this+maxCoord);
   }
 }

 void collect_variation_indices (const hb_subset_plan_t* plan,
                                 hb_set_t& varidx_set /* OUT */) const
 {
   (this+minCoord).collect_variation_indices (varidx_set);
   (this+maxCoord).collect_variation_indices (varidx_set);
   for (const FeatMinMaxRecord& record : featMinMaxRecords)
     record.collect_variation_indices (plan, this, varidx_set);
 }

 bool subset (hb_subset_context_t *c) const
 {
   TRACE_SUBSET (this);
   auto *out = c->serializer->start_embed (*this);
   if (unlikely (!out || !c->serializer->extend_min (out))) return_trace (false);

   if (!(out->minCoord.serialize_subset (c, minCoord, this)) ||
       !(out->maxCoord.serialize_subset (c, maxCoord, this)))
     return_trace (false);

   unsigned len = 0;
   for (const FeatMinMaxRecord& _ : featMinMaxRecords)
   {
     hb_tag_t feature_tag = _.get_feature_tag ();
     if (!c->plan->layout_features.has (feature_tag))
       continue;

     if (!_.subset (c, this)) return false;
     len++;
   }
   return_trace (c->serializer->check_assign (out->featMinMaxRecords.len, len,
                                              HB_SERIALIZE_ERROR_INT_OVERFLOW));
 }

 bool sanitize (hb_sanitize_context_t *c) const
 {
   TRACE_SANITIZE (this);
   return_trace (likely (c->check_struct (this) &&
		  minCoord.sanitize (c, this) &&
		  maxCoord.sanitize (c, this) &&
		  featMinMaxRecords.sanitize (c, this)));
 }

 protected:
 Offset16To<BaseCoord>
	minCoord;	/* Offset to BaseCoord table that defines
			 * minimum extent value, from the beginning
			 * of MinMax table (may be NULL) */
 Offset16To<BaseCoord>
	maxCoord;	/* Offset to BaseCoord table that defines
			 * maximum extent value, from the beginning
			 * of MinMax table (may be NULL) */
 SortedArray16Of<FeatMinMaxRecord>
	featMinMaxRecords;
			/* Array of FeatMinMaxRecords, in alphabetical
			 * order by featureTableTag */
 public:
 DEFINE_SIZE_ARRAY (6, featMinMaxRecords);
};

struct BaseValues
{
 const BaseCoord &get_base_coord (int baseline_tag_index) const
 {
   if (baseline_tag_index == -1) baseline_tag_index = defaultIndex;
   return this+baseCoords[baseline_tag_index];
 }

 void collect_variation_indices (hb_set_t& varidx_set /* OUT */) const
 {
   for (const auto& _ : baseCoords)
     (this+_).collect_variation_indices (varidx_set);
 }

 bool subset (hb_subset_context_t *c) const
 {
   TRACE_SUBSET (this);
   auto *out = c->serializer->start_embed (*this);
   if (unlikely (!out || !c->serializer->extend_min (out))) return_trace (false);
   out->defaultIndex = defaultIndex;

   for (const auto& _ : baseCoords)
     if (!subset_offset_array (c, out->baseCoords, this) (_))
       return_trace (false);

   return_trace (bool (out->baseCoords));
 }

 bool sanitize (hb_sanitize_context_t *c) const
 {
   TRACE_SANITIZE (this);
   return_trace (likely (c->check_struct (this) &&
		  baseCoords.sanitize (c, this)));
 }

 protected:
 Index		defaultIndex;	/* Index number of default baseline for this
			 * script — equals index position of baseline tag
			 * in baselineTags array of the BaseTagList */
 Array16OfOffset16To<BaseCoord>
	baseCoords;	/* Number of BaseCoord tables defined — should equal
			 * baseTagCount in the BaseTagList
			 *
			 * Array of offsets to BaseCoord tables, from beginning of
			 * BaseValues table — order matches baselineTags array in
			 * the BaseTagList */
 public:
 DEFINE_SIZE_ARRAY (4, baseCoords);
};

struct BaseLangSysRecord
{
 int cmp (hb_tag_t key) const { return baseLangSysTag.cmp (key); }

 bool has_data () const { return baseLangSysTag; }

 const MinMax &get_min_max (const void* base) const { return base+minMax; }

 void collect_variation_indices (const void* base,
                                 const hb_subset_plan_t* plan,
                                 hb_set_t& varidx_set /* OUT */) const
 { (base+minMax).collect_variation_indices (plan, varidx_set); }

 bool subset (hb_subset_context_t *c,
              const void *base) const
 {
   TRACE_SUBSET (this);
   auto *out = c->serializer->embed (*this);
   if (unlikely (!out)) return_trace (false);

   return_trace (out->minMax.serialize_subset (c, minMax, base));
 }

 bool sanitize (hb_sanitize_context_t *c, const void *base) const
 {
   TRACE_SANITIZE (this);
   return_trace (likely (c->check_struct (this) &&
		  minMax.sanitize (c, base)));
 }

 protected:
 Tag		baseLangSysTag;	/* 4-byte language system identification tag */
 Offset16To<MinMax>
	minMax;		/* Offset to MinMax table, from beginning
			 * of BaseScript table */
 public:
 DEFINE_SIZE_STATIC (6);
};

struct BaseScript
{
 const MinMax &get_min_max (hb_tag_t language_tag) const
 {
   const BaseLangSysRecord& record = baseLangSysRecords.bsearch (language_tag);
   return record.has_data () ? record.get_min_max (this) : this+defaultMinMax;
 }

 const BaseCoord &get_base_coord (int baseline_tag_index) const
 { return (this+baseValues).get_base_coord (baseline_tag_index); }

 bool has_values () const { return baseValues; }
 bool has_min_max () const { return defaultMinMax || baseLangSysRecords; }

 void collect_variation_indices (const hb_subset_plan_t* plan,
                                 hb_set_t& varidx_set /* OUT */) const
 {
   (this+baseValues).collect_variation_indices (varidx_set);
   (this+defaultMinMax).collect_variation_indices (plan, varidx_set);
   
   for (const BaseLangSysRecord& _ : baseLangSysRecords)
     _.collect_variation_indices (this, plan, varidx_set);
 }

 bool subset (hb_subset_context_t *c) const
 {
   TRACE_SUBSET (this);
   auto *out = c->serializer->start_embed (*this);
   if (unlikely (!out || !c->serializer->extend_min (out))) return_trace (false);

   if (baseValues && !out->baseValues.serialize_subset (c, baseValues, this))
     return_trace (false);

   if (defaultMinMax && !out->defaultMinMax.serialize_subset (c, defaultMinMax, this))
     return_trace (false);

   for (const auto& _ : baseLangSysRecords)
     if (!_.subset (c, this)) return_trace (false);

   return_trace (c->serializer->check_assign (out->baseLangSysRecords.len, baseLangSysRecords.len,
                                              HB_SERIALIZE_ERROR_INT_OVERFLOW));
 }

 bool sanitize (hb_sanitize_context_t *c) const
 {
   TRACE_SANITIZE (this);
   return_trace (likely (c->check_struct (this) &&
		  baseValues.sanitize (c, this) &&
		  defaultMinMax.sanitize (c, this) &&
		  baseLangSysRecords.sanitize (c, this)));
 }

 protected:
 Offset16To<BaseValues>
	baseValues;	/* Offset to BaseValues table, from beginning
			 * of BaseScript table (may be NULL) */
 Offset16To<MinMax>
	defaultMinMax;	/* Offset to MinMax table, from beginning of
			 * BaseScript table (may be NULL) */
 SortedArray16Of<BaseLangSysRecord>
	baseLangSysRecords;
			/* Number of BaseLangSysRecords
			 * defined — may be zero (0) */

 public:
 DEFINE_SIZE_ARRAY (6, baseLangSysRecords);
};

struct BaseScriptList;
struct BaseScriptRecord
{
 int cmp (hb_tag_t key) const { return baseScriptTag.cmp (key); }

 bool has_data () const { return baseScriptTag; }

 hb_tag_t get_script_tag () const { return baseScriptTag; }

 const BaseScript &get_base_script (const BaseScriptList *list) const
 { return list+baseScript; }

 void collect_variation_indices (const hb_subset_plan_t* plan,
                                 const void* list,
                                 hb_set_t& varidx_set /* OUT */) const
 {
   if (!plan->layout_scripts.has (baseScriptTag))
     return;

   (list+baseScript).collect_variation_indices (plan, varidx_set);
 }

 bool subset (hb_subset_context_t *c,
              const void *base) const
 {
   TRACE_SUBSET (this);
   auto *out = c->serializer->embed (*this);
   if (unlikely (!out)) return_trace (false);

   return_trace (out->baseScript.serialize_subset (c, baseScript, base));
 }

 bool sanitize (hb_sanitize_context_t *c, const void *base) const
 {
   TRACE_SANITIZE (this);
   return_trace (likely (c->check_struct (this) &&
		  baseScript.sanitize (c, base)));
 }

 protected:
 Tag		baseScriptTag;	/* 4-byte script identification tag */
 Offset16To<BaseScript>
	baseScript;	/* Offset to BaseScript table, from beginning
			 * of BaseScriptList */

 public:
 DEFINE_SIZE_STATIC (6);
};

struct BaseScriptList
{
 const BaseScript &get_base_script (hb_tag_t script) const
 {
   const BaseScriptRecord *record = &baseScriptRecords.bsearch (script);
   if (!record->has_data ()) record = &baseScriptRecords.bsearch (HB_TAG ('D','F','L','T'));
   return record->has_data () ? record->get_base_script (this) : Null (BaseScript);
 }

 void collect_variation_indices (const hb_subset_plan_t* plan,
                                 hb_set_t& varidx_set /* OUT */) const
 {
   for (const BaseScriptRecord& _ : baseScriptRecords)
     _.collect_variation_indices (plan, this, varidx_set);
 }

 bool subset (hb_subset_context_t *c) const
 {
   TRACE_SUBSET (this);
   auto *out = c->serializer->start_embed (*this);
   if (unlikely (!out || !c->serializer->extend_min (out))) return_trace (false);

   unsigned len = 0;
   for (const BaseScriptRecord& _ : baseScriptRecords)
   {
     hb_tag_t script_tag = _.get_script_tag ();
     if (!c->plan->layout_scripts.has (script_tag))
       continue;

     if (!_.subset (c, this)) return false;
     len++;
   }
   return_trace (c->serializer->check_assign (out->baseScriptRecords.len, len,
                                              HB_SERIALIZE_ERROR_INT_OVERFLOW));
 }

 bool sanitize (hb_sanitize_context_t *c) const
 {
   TRACE_SANITIZE (this);
   return_trace (c->check_struct (this) &&
	  baseScriptRecords.sanitize (c, this));
 }

 protected:
 SortedArray16Of<BaseScriptRecord>
		baseScriptRecords;

 public:
 DEFINE_SIZE_ARRAY (2, baseScriptRecords);
};

struct Axis
{
 bool get_baseline (hb_tag_t          baseline_tag,
	     hb_tag_t          script_tag,
	     hb_tag_t          language_tag,
	     const BaseCoord **coord) const
 {
   const BaseScript &base_script = (this+baseScriptList).get_base_script (script_tag);
   if (!base_script.has_values ())
   {
     *coord = nullptr;
     return false;
   }

   if (likely (coord))
   {
     unsigned int tag_index = 0;
     if (!(this+baseTagList).bfind (baseline_tag, &tag_index))
     {
       *coord = nullptr;
       return false;
     }
     *coord = &base_script.get_base_coord (tag_index);
   }

   return true;
 }

 bool get_min_max (hb_tag_t          script_tag,
	    hb_tag_t          language_tag,
	    hb_tag_t          feature_tag,
	    const BaseCoord **min_coord,
	    const BaseCoord **max_coord) const
 {
   const BaseScript &base_script = (this+baseScriptList).get_base_script (script_tag);
   if (!base_script.has_min_max ())
   {
     *min_coord = *max_coord = nullptr;
     return false;
   }

   base_script.get_min_max (language_tag).get_min_max (feature_tag, min_coord, max_coord);

   return true;
 }

 void collect_variation_indices (const hb_subset_plan_t* plan,
                                 hb_set_t& varidx_set /* OUT */) const
 { (this+baseScriptList).collect_variation_indices (plan, varidx_set); }

 bool subset (hb_subset_context_t *c) const
 {
   TRACE_SUBSET (this);
   auto *out = c->serializer->embed (*this);
   if (unlikely (!out)) return_trace (false);

   out->baseTagList.serialize_copy (c->serializer, baseTagList, this);
   return_trace (out->baseScriptList.serialize_subset (c, baseScriptList, this));
 }

 bool sanitize (hb_sanitize_context_t *c) const
 {
   TRACE_SANITIZE (this);
   return_trace (likely (c->check_struct (this) &&
		  baseTagList.sanitize (c, this) &&
		  baseScriptList.sanitize (c, this)));
 }

 protected:
 Offset16To<SortedArray16Of<Tag>>
	baseTagList;	/* Offset to BaseTagList table, from beginning
			 * of Axis table (may be NULL)
			 * Array of 4-byte baseline identification tags — must
			 * be in alphabetical order */
 Offset16To<BaseScriptList>
	baseScriptList;	/* Offset to BaseScriptList table, from beginning
			 * of Axis table
			 * Array of BaseScriptRecords, in alphabetical order
			 * by baseScriptTag */

 public:
 DEFINE_SIZE_STATIC (4);
};

struct BASE
{
 static constexpr hb_tag_t tableTag = HB_OT_TAG_BASE;

 const Axis &get_axis (hb_direction_t direction) const
 { return HB_DIRECTION_IS_VERTICAL (direction) ? this+vAxis : this+hAxis; }

 bool has_var_store () const
 { return version.to_int () >= 0x00010001u && varStore != 0; }

 const ItemVariationStore &get_var_store () const
 { return version.to_int () < 0x00010001u ? Null (ItemVariationStore) : this+varStore; }

 void collect_variation_indices (const hb_subset_plan_t* plan,
                                 hb_set_t& varidx_set /* OUT */) const
 {
   (this+hAxis).collect_variation_indices (plan, varidx_set);
   (this+vAxis).collect_variation_indices (plan, varidx_set);
 }

 bool subset_varstore (hb_subset_context_t *c,
                       BASE *out /* OUT */) const
 {
   TRACE_SUBSET (this);
   if (!c->serializer->allocate_size<Offset32To<ItemVariationStore>> (Offset32To<ItemVariationStore>::static_size))
       return_trace (false);
   if (!c->plan->normalized_coords)
     return_trace (out->varStore.serialize_subset (c, varStore, this, c->plan->base_varstore_inner_maps.as_array ()));

   if (c->plan->all_axes_pinned)
     return_trace (true);

   item_variations_t item_vars;
   if (!item_vars.instantiate (this+varStore, c->plan, true, true,
                               c->plan->base_varstore_inner_maps.as_array ()))
     return_trace (false);

   if (!out->varStore.serialize_serialize (c->serializer,
                                           item_vars.has_long_word (),
                                           c->plan->axis_tags,
                                           item_vars.get_region_list (),
                                           item_vars.get_vardata_encodings ()))
     return_trace (false);

   const hb_map_t &varidx_map = item_vars.get_varidx_map ();
   /* base_variation_idx_map in the plan is old_varidx->(varidx, delta)
    * mapping, new varidx is generated for subsetting, we need to remap this
    * after instancing */
   for (auto _ : c->plan->base_variation_idx_map.iter_ref ())
   {
     uint32_t varidx = _.second.first;
     uint32_t *new_varidx;
     if (varidx_map.has (varidx, &new_varidx))
       _.second.first = *new_varidx;
     else
       _.second.first = HB_OT_LAYOUT_NO_VARIATIONS_INDEX;
   }
   return_trace (true);
 }

 bool subset (hb_subset_context_t *c) const
 {
   TRACE_SUBSET (this);
   auto *out = c->serializer->start_embed (*this);
   if (unlikely (!out || !c->serializer->extend_min (out))) return_trace (false);

   out->version = version;
   if (has_var_store () && !subset_varstore (c, out))
       return_trace (false);

   if (hAxis && !out->hAxis.serialize_subset (c, hAxis, this))
     return_trace (false);

   if (vAxis && !out->vAxis.serialize_subset (c, vAxis, this))
     return_trace (false);

   return_trace (true);
 }

 bool get_baseline (hb_font_t      *font,
	     hb_tag_t        baseline_tag,
	     hb_direction_t  direction,
	     hb_tag_t        script_tag,
	     hb_tag_t        language_tag,
	     hb_position_t  *base) const
 {
   const BaseCoord *base_coord = nullptr;
   if (unlikely (!get_axis (direction).get_baseline (baseline_tag, script_tag, language_tag, &base_coord) ||
	  !base_coord || !base_coord->has_data ()))
     return false;

   if (likely (base))
     *base = base_coord->get_coord (font, get_var_store (), direction);

   return true;
 }

 bool get_min_max (hb_font_t      *font,
	    hb_direction_t  direction,
	    hb_tag_t        script_tag,
	    hb_tag_t        language_tag,
	    hb_tag_t        feature_tag,
	    hb_position_t  *min,
	    hb_position_t  *max) const
 {
   const BaseCoord *min_coord, *max_coord;
   if (!get_axis (direction).get_min_max (script_tag, language_tag, feature_tag,
				   &min_coord, &max_coord))
     return false;

   const ItemVariationStore &var_store = get_var_store ();
   if (likely (min && min_coord)) *min = min_coord->get_coord (font, var_store, direction);
   if (likely (max && max_coord)) *max = max_coord->get_coord (font, var_store, direction);
   return true;
 }

 bool sanitize (hb_sanitize_context_t *c) const
 {
   TRACE_SANITIZE (this);
   return_trace (likely (c->check_struct (this) &&
		  hb_barrier () &&
		  likely (version.major == 1) &&
		  hAxis.sanitize (c, this) &&
		  vAxis.sanitize (c, this) &&
		  (version.to_int () < 0x00010001u || varStore.sanitize (c, this))));
 }

 protected:
 FixedVersion<>version;	/* Version of the BASE table */
 Offset16To<Axis>hAxis;		/* Offset to horizontal Axis table, from beginning
			 * of BASE table (may be NULL) */
 Offset16To<Axis>vAxis;		/* Offset to vertical Axis table, from beginning
			 * of BASE table (may be NULL) */
 Offset32To<ItemVariationStore>
	varStore;	/* Offset to the table of Item Variation
			 * Store--from beginning of BASE
			 * header (may be NULL).  Introduced
			 * in version 0x00010001. */
 public:
 DEFINE_SIZE_MIN (8);
};


} /* namespace OT */


#endif /* HB_OT_LAYOUT_BASE_TABLE_HH */