src/hb-face.cc - third_party/harfbuzz - Git at Google

 /*
  * Copyright © 2009  Red Hat, Inc.
  * Copyright © 2012  Google, Inc.
  *
  *  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.
  *
  * Red Hat Author(s): Behdad Esfahbod
  * Google Author(s): Behdad Esfahbod
  */

 #include "hb-private.hh"

 #include "hb-face-private.hh"
 #include "hb-open-file-private.hh"
 #include "hb-ot-head-table.hh"
 #include "hb-ot-maxp-table.hh"


 /*
  * hb_face_t
  */

 const hb_face_t _hb_face_nil = {
   HB_OBJECT_HEADER_STATIC,

   true, /* immutable */

   nullptr, /* reference_table_func */
   nullptr, /* user_data */
   nullptr, /* destroy */

   0,    /* index */
   1000, /* upem */
   0,    /* num_glyphs */

   {
 #define HB_SHAPER_IMPLEMENT(shaper) HB_SHAPER_DATA_INVALID,
 #include "hb-shaper-list.hh"
 #undef HB_SHAPER_IMPLEMENT
   },

   nullptr, /* shape_plans */
 };


 /**
  * hb_face_create_for_tables:
  * @reference_table_func: (closure user_data) (destroy destroy) (scope notified):
  * @user_data:
  * @destroy:
  *
  *
  *
  * Return value: (transfer full)
  *
  * Since: 0.9.2
  **/
 hb_face_t *
 hb_face_create_for_tables (hb_reference_table_func_t  reference_table_func,
 			   void                      *user_data,
 			   hb_destroy_func_t          destroy)
 {
   hb_face_t *face;

   if (!reference_table_func || !(face = hb_object_create<hb_face_t> ())) {
     if (destroy)
       destroy (user_data);
     return hb_face_get_empty ();
   }

   face->reference_table_func = reference_table_func;
   face->user_data = user_data;
   face->destroy = destroy;

   face->upem = 0;
   face->num_glyphs = (unsigned int) -1;

   return face;
 }


 typedef struct hb_face_for_data_closure_t {
   hb_blob_t *blob;
   unsigned int  index;
 } hb_face_for_data_closure_t;

 static hb_face_for_data_closure_t *
 _hb_face_for_data_closure_create (hb_blob_t *blob, unsigned int index)
 {
   hb_face_for_data_closure_t *closure;

   closure = (hb_face_for_data_closure_t *) calloc (1, sizeof (hb_face_for_data_closure_t));
   if (unlikely (!closure))
     return nullptr;

   closure->blob = blob;
   closure->index = index;

   return closure;
 }

 static void
 _hb_face_for_data_closure_destroy (void *data)
 {
   hb_face_for_data_closure_t *closure = (hb_face_for_data_closure_t *) data;

   hb_blob_destroy (closure->blob);
   free (closure);
 }

 static hb_blob_t *
 _hb_face_for_data_reference_table (hb_face_t *face HB_UNUSED, hb_tag_t tag, void *user_data)
 {
   hb_face_for_data_closure_t *data = (hb_face_for_data_closure_t *) user_data;

   if (tag == HB_TAG_NONE)
     return hb_blob_reference (data->blob);

   const OT::OpenTypeFontFile &ot_file = *OT::Sanitizer<OT::OpenTypeFontFile>::lock_instance (data->blob);
   const OT::OpenTypeFontFace &ot_face = ot_file.get_face (data->index);

   const OT::OpenTypeTable &table = ot_face.get_table_by_tag (tag);

   hb_blob_t *blob = hb_blob_create_sub_blob (data->blob, table.offset, table.length);

   return blob;
 }

 /**
  * hb_face_create: (Xconstructor)
  * @blob:
  * @index:
  *
  *
  *
  * Return value: (transfer full):
  *
  * Since: 0.9.2
  **/
 hb_face_t *
 hb_face_create (hb_blob_t    *blob,
 		unsigned int  index)
 {
   hb_face_t *face;

   if (unlikely (!blob))
     blob = hb_blob_get_empty ();

   hb_face_for_data_closure_t *closure = _hb_face_for_data_closure_create (OT::Sanitizer<OT::OpenTypeFontFile>().sanitize (hb_blob_reference (blob)), index);

   if (unlikely (!closure))
     return hb_face_get_empty ();

   face = hb_face_create_for_tables (_hb_face_for_data_reference_table,
 				    closure,
 				    _hb_face_for_data_closure_destroy);

   face->index = index;

   return face;
 }

 /**
  * hb_face_get_empty:
  *
  *
  *
  * Return value: (transfer full)
  *
  * Since: 0.9.2
  **/
 hb_face_t *
 hb_face_get_empty (void)
 {
   return const_cast<hb_face_t *> (&_hb_face_nil);
 }


 /**
  * hb_face_reference: (skip)
  * @face: a face.
  *
  *
  *
  * Return value:
  *
  * Since: 0.9.2
  **/
 hb_face_t *
 hb_face_reference (hb_face_t *face)
 {
   return hb_object_reference (face);
 }

 /**
  * hb_face_destroy: (skip)
  * @face: a face.
  *
  *
  *
  * Since: 0.9.2
  **/
 void
 hb_face_destroy (hb_face_t *face)
 {
   if (!hb_object_destroy (face)) return;

   for (hb_face_t::plan_node_t *node = face->shape_plans; node; )
   {
     hb_face_t::plan_node_t *next = node->next;
     hb_shape_plan_destroy (node->shape_plan);
     free (node);
     node = next;
   }

 #define HB_SHAPER_IMPLEMENT(shaper) HB_SHAPER_DATA_DESTROY(shaper, face);
 #include "hb-shaper-list.hh"
 #undef HB_SHAPER_IMPLEMENT

   if (face->destroy)
     face->destroy (face->user_data);

   free (face);
 }

 /**
  * hb_face_set_user_data: (skip)
  * @face: a face.
  * @key:
  * @data:
  * @destroy:
  * @replace:
  *
  *
  *
  * Return value:
  *
  * Since: 0.9.2
  **/
 hb_bool_t
 hb_face_set_user_data (hb_face_t          *face,
 		       hb_user_data_key_t *key,
 		       void *              data,
 		       hb_destroy_func_t   destroy,
 		       hb_bool_t           replace)
 {
   return hb_object_set_user_data (face, key, data, destroy, replace);
 }

 /**
  * hb_face_get_user_data: (skip)
  * @face: a face.
  * @key:
  *
  *
  *
  * Return value: (transfer none):
  *
  * Since: 0.9.2
  **/
 void *
 hb_face_get_user_data (hb_face_t          *face,
 		       hb_user_data_key_t *key)
 {
   return hb_object_get_user_data (face, key);
 }

 /**
  * hb_face_make_immutable:
  * @face: a face.
  *
  *
  *
  * Since: 0.9.2
  **/
 void
 hb_face_make_immutable (hb_face_t *face)
 {
   if (unlikely (hb_object_is_inert (face)))
     return;

   face->immutable = true;
 }

 /**
  * hb_face_is_immutable:
  * @face: a face.
  *
  *
  *
  * Return value:
  *
  * Since: 0.9.2
  **/
 hb_bool_t
 hb_face_is_immutable (hb_face_t *face)
 {
   return face->immutable;
 }


 /**
  * hb_face_reference_table:
  * @face: a face.
  * @tag:
  *
  *
  *
  * Return value: (transfer full):
  *
  * Since: 0.9.2
  **/
 hb_blob_t *
 hb_face_reference_table (hb_face_t *face,
 			 hb_tag_t   tag)
 {
   return face->reference_table (tag);
 }

 /**
  * hb_face_reference_blob:
  * @face: a face.
  *
  *
  *
  * Return value: (transfer full):
  *
  * Since: 0.9.2
  **/
 hb_blob_t *
 hb_face_reference_blob (hb_face_t *face)
 {
   return face->reference_table (HB_TAG_NONE);
 }

 /**
  * hb_face_set_index:
  * @face: a face.
  * @index:
  *
  *
  *
  * Since: 0.9.2
  **/
 void
 hb_face_set_index (hb_face_t    *face,
 		   unsigned int  index)
 {
   if (face->immutable)
     return;

   face->index = index;
 }

 /**
  * hb_face_get_index:
  * @face: a face.
  *
  *
  *
  * Return value:
  *
  * Since: 0.9.2
  **/
 unsigned int
 hb_face_get_index (hb_face_t    *face)
 {
   return face->index;
 }

 /**
  * hb_face_set_upem:
  * @face: a face.
  * @upem:
  *
  *
  *
  * Since: 0.9.2
  **/
 void
 hb_face_set_upem (hb_face_t    *face,
 		  unsigned int  upem)
 {
   if (face->immutable)
     return;

   face->upem = upem;
 }

 /**
  * hb_face_get_upem:
  * @face: a face.
  *
  *
  *
  * Return value:
  *
  * Since: 0.9.2
  **/
 unsigned int
 hb_face_get_upem (hb_face_t *face)
 {
   return face->get_upem ();
 }

 void
 hb_face_t::load_upem (void) const
 {
   hb_blob_t *head_blob = OT::Sanitizer<OT::head>().sanitize (reference_table (HB_OT_TAG_head));
   const OT::head *head_table = OT::Sanitizer<OT::head>::lock_instance (head_blob);
   upem = head_table->get_upem ();
   hb_blob_destroy (head_blob);
 }

 /**
  * hb_face_set_glyph_count:
  * @face: a face.
  * @glyph_count:
  *
  *
  *
  * Since: 0.9.7
  **/
 void
 hb_face_set_glyph_count (hb_face_t    *face,
 			 unsigned int  glyph_count)
 {
   if (face->immutable)
     return;

   face->num_glyphs = glyph_count;
 }

 /**
  * hb_face_get_glyph_count:
  * @face: a face.
  *
  *
  *
  * Return value:
  *
  * Since: 0.9.7
  **/
 unsigned int
 hb_face_get_glyph_count (hb_face_t *face)
 {
   return face->get_num_glyphs ();
 }

 void
 hb_face_t::load_num_glyphs (void) const
 {
   hb_blob_t *maxp_blob = OT::Sanitizer<OT::maxp>().sanitize (reference_table (HB_OT_TAG_maxp));
   const OT::maxp *maxp_table = OT::Sanitizer<OT::maxp>::lock_instance (maxp_blob);
   num_glyphs = maxp_table->get_num_glyphs ();
   hb_blob_destroy (maxp_blob);
 }

 /**
  * hb_face_get_table_tags:
  * @face: a face.
  *
  * Retrieves table tags for a face, if possible.
  *
  * Return value: total number of tables, or 0 if not possible to list.
  *
  * Since: 1.6.0
  **/
 unsigned int
 hb_face_get_table_tags (hb_face_t    *face,
 			unsigned int  start_offset,
 			unsigned int *table_count, /* IN/OUT */
 			hb_tag_t     *table_tags /* OUT */)
 {
   if (face->destroy != _hb_face_for_data_closure_destroy)
   {
     if (table_count)
       *table_count = 0;
     return 0;
   }

   hb_face_for_data_closure_t *data = (hb_face_for_data_closure_t *) face->user_data;

   const OT::OpenTypeFontFile &ot_file = *OT::Sanitizer<OT::OpenTypeFontFile>::lock_instance (data->blob);
   const OT::OpenTypeFontFace &ot_face = ot_file.get_face (data->index);

   return ot_face.get_table_tags (start_offset, table_count, table_tags);
 }
	/*
	* Copyright © 2009 Red Hat, Inc.
	* Copyright © 2012 Google, Inc.
	*
	* 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.
	*
	* Red Hat Author(s): Behdad Esfahbod
	* Google Author(s): Behdad Esfahbod
	*/

	#include "hb-private.hh"

	#include "hb-face-private.hh"
	#include "hb-open-file-private.hh"
	#include "hb-ot-head-table.hh"
	#include "hb-ot-maxp-table.hh"


	/*
	* hb_face_t
	*/

	const hb_face_t _hb_face_nil = {
	HB_OBJECT_HEADER_STATIC,

	true, /* immutable */

	nullptr, /* reference_table_func */
	nullptr, /* user_data */
	nullptr, /* destroy */

	0, /* index */
	1000, /* upem */
	0, /* num_glyphs */

	{
	#define HB_SHAPER_IMPLEMENT(shaper) HB_SHAPER_DATA_INVALID,
	#include "hb-shaper-list.hh"
	#undef HB_SHAPER_IMPLEMENT
	},

	nullptr, /* shape_plans */
	};


	/**
	* hb_face_create_for_tables:
	* @reference_table_func: (closure user_data) (destroy destroy) (scope notified):
	* @user_data:
	* @destroy:
	*
	*
	*
	* Return value: (transfer full)
	*
	* Since: 0.9.2
	**/
	hb_face_t *
	hb_face_create_for_tables (hb_reference_table_func_t reference_table_func,
	void *user_data,
	hb_destroy_func_t destroy)
	{
	hb_face_t *face;

	if (!reference_table_func \|\| !(face = hb_object_create<hb_face_t> ())) {
	if (destroy)
	destroy (user_data);
	return hb_face_get_empty ();
	}

	face->reference_table_func = reference_table_func;
	face->user_data = user_data;
	face->destroy = destroy;

	face->upem = 0;
	face->num_glyphs = (unsigned int) -1;

	return face;
	}


	typedef struct hb_face_for_data_closure_t {
	hb_blob_t *blob;
	unsigned int index;
	} hb_face_for_data_closure_t;

	static hb_face_for_data_closure_t *
	_hb_face_for_data_closure_create (hb_blob_t *blob, unsigned int index)
	{
	hb_face_for_data_closure_t *closure;

	closure = (hb_face_for_data_closure_t *) calloc (1, sizeof (hb_face_for_data_closure_t));
	if (unlikely (!closure))
	return nullptr;

	closure->blob = blob;
	closure->index = index;

	return closure;
	}

	static void
	_hb_face_for_data_closure_destroy (void *data)
	{
	hb_face_for_data_closure_t closure = (hb_face_for_data_closure_t ) data;

	hb_blob_destroy (closure->blob);
	free (closure);
	}

	static hb_blob_t *
	_hb_face_for_data_reference_table (hb_face_t face HB_UNUSED, hb_tag_t tag, void user_data)
	{
	hb_face_for_data_closure_t data = (hb_face_for_data_closure_t ) user_data;

	if (tag == HB_TAG_NONE)
	return hb_blob_reference (data->blob);

	const OT::OpenTypeFontFile &ot_file = *OT::Sanitizer<OT::OpenTypeFontFile>::lock_instance (data->blob);
	const OT::OpenTypeFontFace &ot_face = ot_file.get_face (data->index);

	const OT::OpenTypeTable &table = ot_face.get_table_by_tag (tag);

	hb_blob_t *blob = hb_blob_create_sub_blob (data->blob, table.offset, table.length);

	return blob;
	}

	/**
	* hb_face_create: (Xconstructor)
	* @blob:
	* @index:
	*
	*
	*
	* Return value: (transfer full):
	*
	* Since: 0.9.2
	**/
	hb_face_t *
	hb_face_create (hb_blob_t *blob,
	unsigned int index)
	{
	hb_face_t *face;

	if (unlikely (!blob))
	blob = hb_blob_get_empty ();

	hb_face_for_data_closure_t *closure = _hb_face_for_data_closure_create (OT::Sanitizer<OT::OpenTypeFontFile>().sanitize (hb_blob_reference (blob)), index);

	if (unlikely (!closure))
	return hb_face_get_empty ();

	face = hb_face_create_for_tables (_hb_face_for_data_reference_table,
	closure,
	_hb_face_for_data_closure_destroy);

	face->index = index;

	return face;
	}

	/**
	* hb_face_get_empty:
	*
	*
	*
	* Return value: (transfer full)
	*
	* Since: 0.9.2
	**/
	hb_face_t *
	hb_face_get_empty (void)
	{
	return const_cast<hb_face_t *> (&_hb_face_nil);
	}


	/**
	* hb_face_reference: (skip)
	* @face: a face.
	*
	*
	*
	* Return value:
	*
	* Since: 0.9.2
	**/
	hb_face_t *
	hb_face_reference (hb_face_t *face)
	{
	return hb_object_reference (face);
	}

	/**
	* hb_face_destroy: (skip)
	* @face: a face.
	*
	*
	*
	* Since: 0.9.2
	**/
	void
	hb_face_destroy (hb_face_t *face)
	{
	if (!hb_object_destroy (face)) return;

	for (hb_face_t::plan_node_t *node = face->shape_plans; node; )
	{
	hb_face_t::plan_node_t *next = node->next;
	hb_shape_plan_destroy (node->shape_plan);
	free (node);
	node = next;
	}

	#define HB_SHAPER_IMPLEMENT(shaper) HB_SHAPER_DATA_DESTROY(shaper, face);
	#include "hb-shaper-list.hh"
	#undef HB_SHAPER_IMPLEMENT

	if (face->destroy)
	face->destroy (face->user_data);

	free (face);
	}

	/**
	* hb_face_set_user_data: (skip)
	* @face: a face.
	* @key:
	* @data:
	* @destroy:
	* @replace:
	*
	*
	*
	* Return value:
	*
	* Since: 0.9.2
	**/
	hb_bool_t
	hb_face_set_user_data (hb_face_t *face,
	hb_user_data_key_t *key,
	void * data,
	hb_destroy_func_t destroy,
	hb_bool_t replace)
	{
	return hb_object_set_user_data (face, key, data, destroy, replace);
	}

	/**
	* hb_face_get_user_data: (skip)
	* @face: a face.
	* @key:
	*
	*
	*
	* Return value: (transfer none):
	*
	* Since: 0.9.2
	**/
	void *
	hb_face_get_user_data (hb_face_t *face,
	hb_user_data_key_t *key)
	{
	return hb_object_get_user_data (face, key);
	}

	/**
	* hb_face_make_immutable:
	* @face: a face.
	*
	*
	*
	* Since: 0.9.2
	**/
	void
	hb_face_make_immutable (hb_face_t *face)
	{
	if (unlikely (hb_object_is_inert (face)))
	return;

	face->immutable = true;
	}

	/**
	* hb_face_is_immutable:
	* @face: a face.
	*
	*
	*
	* Return value:
	*
	* Since: 0.9.2
	**/
	hb_bool_t
	hb_face_is_immutable (hb_face_t *face)
	{
	return face->immutable;
	}


	/**
	* hb_face_reference_table:
	* @face: a face.
	* @tag:
	*
	*
	*
	* Return value: (transfer full):
	*
	* Since: 0.9.2
	**/
	hb_blob_t *
	hb_face_reference_table (hb_face_t *face,
	hb_tag_t tag)
	{
	return face->reference_table (tag);
	}

	/**
	* hb_face_reference_blob:
	* @face: a face.
	*
	*
	*
	* Return value: (transfer full):
	*
	* Since: 0.9.2
	**/
	hb_blob_t *
	hb_face_reference_blob (hb_face_t *face)
	{
	return face->reference_table (HB_TAG_NONE);
	}

	/**
	* hb_face_set_index:
	* @face: a face.
	* @index:
	*
	*
	*
	* Since: 0.9.2
	**/
	void
	hb_face_set_index (hb_face_t *face,
	unsigned int index)
	{
	if (face->immutable)
	return;

	face->index = index;
	}

	/**
	* hb_face_get_index:
	* @face: a face.
	*
	*
	*
	* Return value:
	*
	* Since: 0.9.2
	**/
	unsigned int
	hb_face_get_index (hb_face_t *face)
	{
	return face->index;
	}

	/**
	* hb_face_set_upem:
	* @face: a face.
	* @upem:
	*
	*
	*
	* Since: 0.9.2
	**/
	void
	hb_face_set_upem (hb_face_t *face,
	unsigned int upem)
	{
	if (face->immutable)
	return;

	face->upem = upem;
	}

	/**
	* hb_face_get_upem:
	* @face: a face.
	*
	*
	*
	* Return value:
	*
	* Since: 0.9.2
	**/
	unsigned int
	hb_face_get_upem (hb_face_t *face)
	{
	return face->get_upem ();
	}

	void
	hb_face_t::load_upem (void) const
	{
	hb_blob_t *head_blob = OT::Sanitizer<OT::head>().sanitize (reference_table (HB_OT_TAG_head));
	const OT::head *head_table = OT::Sanitizer<OT::head>::lock_instance (head_blob);
	upem = head_table->get_upem ();
	hb_blob_destroy (head_blob);
	}

	/**
	* hb_face_set_glyph_count:
	* @face: a face.
	* @glyph_count:
	*
	*
	*
	* Since: 0.9.7
	**/
	void
	hb_face_set_glyph_count (hb_face_t *face,
	unsigned int glyph_count)
	{
	if (face->immutable)
	return;

	face->num_glyphs = glyph_count;
	}

	/**
	* hb_face_get_glyph_count:
	* @face: a face.
	*
	*
	*
	* Return value:
	*
	* Since: 0.9.7
	**/
	unsigned int
	hb_face_get_glyph_count (hb_face_t *face)
	{
	return face->get_num_glyphs ();
	}

	void
	hb_face_t::load_num_glyphs (void) const
	{
	hb_blob_t *maxp_blob = OT::Sanitizer<OT::maxp>().sanitize (reference_table (HB_OT_TAG_maxp));
	const OT::maxp *maxp_table = OT::Sanitizer<OT::maxp>::lock_instance (maxp_blob);
	num_glyphs = maxp_table->get_num_glyphs ();
	hb_blob_destroy (maxp_blob);
	}

	/**
	* hb_face_get_table_tags:
	* @face: a face.
	*
	* Retrieves table tags for a face, if possible.
	*
	* Return value: total number of tables, or 0 if not possible to list.
	*
	* Since: 1.6.0
	**/
	unsigned int
	hb_face_get_table_tags (hb_face_t *face,
	unsigned int start_offset,
	unsigned int table_count, / IN/OUT */
	hb_tag_t table_tags / OUT */)
	{
	if (face->destroy != _hb_face_for_data_closure_destroy)
	{
	if (table_count)
	*table_count = 0;
	return 0;
	}

	hb_face_for_data_closure_t data = (hb_face_for_data_closure_t ) face->user_data;

	const OT::OpenTypeFontFile &ot_file = *OT::Sanitizer<OT::OpenTypeFontFile>::lock_instance (data->blob);
	const OT::OpenTypeFontFace &ot_face = ot_file.get_face (data->index);

	return ot_face.get_table_tags (start_offset, table_count, table_tags);
	}