tor-browser

hb-face.cc (25917B)

---

/*
* 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.hh"

#include "hb-face.hh"
#include "hb-blob.hh"
#include "hb-open-file.hh"
#include "hb-ot-face.hh"
#include "hb-ot-cmap-table.hh"

#ifdef HAVE_FREETYPE
#include "hb-ft.h"
#endif
#ifdef HAVE_CORETEXT
#include "hb-coretext.h"
#endif
#ifdef HAVE_DIRECTWRITE
#include "hb-directwrite.h"
#endif


/**
* SECTION:hb-face
* @title: hb-face
* @short_description: Font face objects
* @include: hb.h
*
* A font face is an object that represents a single face from within a
* font family.
*
* More precisely, a font face represents a single face in a binary font file.
* Font faces are typically built from a binary blob and a face index.
* Font faces are used to create fonts.
*
* A font face can be created from a binary blob using hb_face_create().
* The face index is used to select a face from a binary blob that contains
* multiple faces.  For example, a binary blob that contains both a regular
* and a bold face can be used to create two font faces, one for each face
* index.
**/


/**
* hb_face_count:
* @blob: a blob.
*
* Fetches the number of faces in a blob.
*
* Return value: Number of faces in @blob
*
* Since: 1.7.7
**/
unsigned int
hb_face_count (hb_blob_t *blob)
{
 if (unlikely (!blob))
   return 0;

 hb_sanitize_context_t c (blob);

 auto *ot = blob->as<OT::OpenTypeFontFile> ();
 if (unlikely (!ot->sanitize (&c)))
   return 0;

 return ot->get_face_count ();
}

/*
* hb_face_t
*/

DEFINE_NULL_INSTANCE (hb_face_t) =
{
 HB_OBJECT_HEADER_STATIC,

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

 /* Zero for the rest is fine. */
};


/**
* hb_face_create_for_tables:
* @reference_table_func: (closure user_data) (destroy destroy) (scope notified): Table-referencing function
* @user_data: A pointer to the user data
* @destroy: (nullable): A callback to call when @data is not needed anymore
*
* Variant of hb_face_create(), built for those cases where it is more
* convenient to provide data for individual tables instead of the whole font
* data. With the caveat that hb_face_get_table_tags() would not work
* with faces created this way. You can address that by calling the
* hb_face_set_get_table_tags_func() function and setting the appropriate callback.
*
* Creates a new face object from the specified @user_data and @reference_table_func,
* with the @destroy callback.
*
* Return value: (transfer full): The new face object
*
* 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->num_glyphs = -1;

 face->data.init0 (face);
 face->table.init0 (face);

 return face;
}


typedef struct hb_face_for_data_closure_t {
 hb_blob_t *blob;
 uint16_t  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 *) hb_calloc (1, sizeof (hb_face_for_data_closure_t));
 if (unlikely (!closure))
   return nullptr;

 closure->blob = blob;
 closure->index = (uint16_t) (index & 0xFFFFu);

 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);
 hb_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 = *data->blob->as<OT::OpenTypeFontFile> ();
 unsigned int base_offset;
 const OT::OpenTypeFontFace &ot_face = ot_file.get_face (data->index, &base_offset);

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

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

 return blob;
}

static unsigned
_hb_face_for_data_get_table_tags (const hb_face_t *face HB_UNUSED,
			  unsigned int start_offset,
			  unsigned int *table_count,
			  hb_tag_t *table_tags,
			  void *user_data)
{
 hb_face_for_data_closure_t *data = (hb_face_for_data_closure_t *) user_data;

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

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


/**
* hb_face_create:
* @blob: #hb_blob_t to work upon
* @index: The index of the face within @blob
*
* Constructs a new face object from the specified blob and
* a face index into that blob.
*
* The face index is used for blobs of file formats such as TTC and
* DFont that can contain more than one face.  Face indices within
* such collections are zero-based.
*
* <note>Note: If the blob font format is not a collection, @index
* is ignored.  Otherwise, only the lower 16-bits of @index are used.
* The unmodified @index can be accessed via hb_face_get_index().</note>
*
* <note>Note: The high 16-bits of @index, if non-zero, are used by
* hb_font_create() to load named-instances in variable fonts.  See
* hb_font_create() for details.</note>
*
* Return value: (transfer full): The new face object
*
* 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 ();

 blob = hb_sanitize_context_t ().sanitize_blob<OT::OpenTypeFontFile> (hb_blob_reference (blob));

 hb_face_for_data_closure_t *closure = _hb_face_for_data_closure_create (blob, index);

 if (unlikely (!closure))
 {
   hb_blob_destroy (blob);
   return hb_face_get_empty ();
 }

 face = hb_face_create_for_tables (_hb_face_for_data_reference_table,
			    closure,
			    _hb_face_for_data_closure_destroy);
 hb_face_set_get_table_tags_func (face,
			   _hb_face_for_data_get_table_tags,
			   closure,
			   nullptr);

 face->index = index;

 return face;
}

/**
* hb_face_create_or_fail:
* @blob: #hb_blob_t to work upon
* @index: The index of the face within @blob
*
* Like hb_face_create(), but returns `NULL` if the blob data
* contains no usable font face at the specified index.
*
* Return value: (transfer full): The new face object, or `NULL` if
* no face is found at the specified index.
*
* Since: 10.1.0
**/
hb_face_t *
hb_face_create_or_fail (hb_blob_t    *blob,
		unsigned int  index)
{
 unsigned num_faces = hb_face_count (blob);
 if (index >= num_faces)
   return nullptr;

 hb_face_t *face = hb_face_create (blob, index);
 if (hb_object_is_immutable (face))
   return nullptr;

 return face;
}

#ifndef HB_NO_OPEN
/**
* hb_face_create_from_file_or_fail:
* @file_name: A font filename
* @index: The index of the face within the file
*
* A thin wrapper around hb_blob_create_from_file_or_fail()
* followed by hb_face_create_or_fail().
*
* Return value: (transfer full): The new face object, or `NULL` if
* no face is found at the specified index or the file cannot be read.
*
* Since: 10.1.0
**/
HB_EXTERN hb_face_t *
hb_face_create_from_file_or_fail (const char   *file_name,
			  unsigned int  index)
{
 hb_blob_t *blob = hb_blob_create_from_file_or_fail (file_name);
 if (unlikely (!blob))
   return nullptr;

 hb_face_t *face = hb_face_create_or_fail (blob, index);
 hb_blob_destroy (blob);

 return face;
}

static const struct supported_face_loaders_t {
char name[16];
hb_face_t * (*from_file) (const char *font_file, unsigned face_index);
hb_face_t * (*from_blob) (hb_blob_t *blob, unsigned face_index);
} supported_face_loaders[] =
{
 {"ot",
#ifndef HB_NO_OPEN
  hb_face_create_from_file_or_fail,
#else
  nullptr,
#endif
  hb_face_create_or_fail
 },
#ifdef HAVE_FREETYPE
 {"ft",
  hb_ft_face_create_from_file_or_fail,
  hb_ft_face_create_from_blob_or_fail
 },
#endif
#ifdef HAVE_CORETEXT
 {"coretext",
  hb_coretext_face_create_from_file_or_fail,
  hb_coretext_face_create_from_blob_or_fail
 },
#endif
#ifdef HAVE_DIRECTWRITE
 {"directwrite",
  hb_directwrite_face_create_from_file_or_fail,
  hb_directwrite_face_create_from_blob_or_fail
 },
#endif
};

static const char *get_default_loader_name ()
{
 static hb_atomic_t<const char *> static_loader_name;
 const char *loader_name = static_loader_name.get_acquire ();
 if (!loader_name)
 {
   loader_name = getenv ("HB_FACE_LOADER");
   if (!loader_name)
     loader_name = "";
   if (!static_loader_name.cmpexch (nullptr, loader_name))
     loader_name = static_loader_name.get_acquire ();
 }
 return loader_name;
}

/**
* hb_face_create_from_file_or_fail_using:
* @file_name: A font filename
* @index: The index of the face within the file
* @loader_name: (nullable): The name of the loader to use, or `NULL`
*
* A thin wrapper around the face loader functions registered with HarfBuzz.
* If @loader_name is `NULL` or the empty string, the first available loader
* is used.
*
* For example, the FreeType ("ft") loader might be able to load
* WOFF and WOFF2 files if FreeType is built with those features,
* whereas the OpenType ("ot") loader will not.
*
* Return value: (transfer full): The new face object, or `NULL` if
* the file cannot be read or the loader fails to load the face.
*
* Since: 11.0.0
**/
hb_face_t *
hb_face_create_from_file_or_fail_using (const char   *file_name,
				unsigned int  index,
				const char   *loader_name)
{
 // Duplicated in hb_face_create_or_fail_using
 bool retry = false;
 if (!loader_name || !*loader_name)
 {
   loader_name = get_default_loader_name ();
   retry = true;
 }
 if (loader_name && !*loader_name) loader_name = nullptr;

retry:
 for (unsigned i = 0; i < ARRAY_LENGTH (supported_face_loaders); i++)
 {
   if (!loader_name || (supported_face_loaders[i].from_file && !strcmp (supported_face_loaders[i].name, loader_name)))
     return supported_face_loaders[i].from_file (file_name, index);
 }

 if (retry)
 {
   retry = false;
   loader_name = nullptr;
   goto retry;
 }

 return nullptr;
}

/**
* hb_face_create_or_fail_using:
* @blob: #hb_blob_t to work upon
* @index: The index of the face within @blob
* @loader_name: (nullable): The name of the loader to use, or `NULL`
*
* A thin wrapper around the face loader functions registered with HarfBuzz.
* If @loader_name is `NULL` or the empty string, the first available loader
* is used.
*
* For example, the FreeType ("ft") loader might be able to load
* WOFF and WOFF2 files if FreeType is built with those features,
* whereas the OpenType ("ot") loader will not.
*
* Return value: (transfer full): The new face object, or `NULL` if
* the loader fails to load the face.
*
* Since: 11.0.0
**/
hb_face_t *
hb_face_create_or_fail_using (hb_blob_t    *blob,
		      unsigned int  index,
		      const char   *loader_name)
{
 // Duplicated in hb_face_create_from_file_or_fail_using
 bool retry = false;
 if (!loader_name || !*loader_name)
 {
   loader_name = get_default_loader_name ();
   retry = true;
 }
 if (loader_name && !*loader_name) loader_name = nullptr;

retry:
 for (unsigned i = 0; i < ARRAY_LENGTH (supported_face_loaders); i++)
 {
   if (!loader_name || (supported_face_loaders[i].from_blob && !strcmp (supported_face_loaders[i].name, loader_name)))
     return supported_face_loaders[i].from_blob (blob, index);
 }

 if (retry)
 {
   retry = false;
   loader_name = nullptr;
   goto retry;
 }

 return nullptr;
}

static inline void free_static_face_loader_list ();

static const char * const nil_face_loader_list[] = {nullptr};

static struct hb_face_loader_list_lazy_loader_t : hb_lazy_loader_t<const char *,
							  hb_face_loader_list_lazy_loader_t>
{
 static const char ** create ()
 {
   const char **face_loader_list = (const char **) hb_calloc (1 + ARRAY_LENGTH (supported_face_loaders), sizeof (const char *));
   if (unlikely (!face_loader_list))
     return nullptr;

   unsigned i;
   for (i = 0; i < ARRAY_LENGTH (supported_face_loaders); i++)
     face_loader_list[i] = supported_face_loaders[i].name;
   face_loader_list[i] = nullptr;

   hb_atexit (free_static_face_loader_list);

   return face_loader_list;
 }
 static void destroy (const char **l)
 { hb_free (l); }
 static const char * const * get_null ()
 { return nil_face_loader_list; }
} static_face_loader_list;

static inline
void free_static_face_loader_list ()
{
 static_face_loader_list.free_instance ();
}

/**
* hb_face_list_loaders:
*
* Retrieves the list of face loaders supported by HarfBuzz.
*
* Return value: (transfer none) (array zero-terminated=1): a
*    `NULL`-terminated array of supported face loaders
*    constant strings. The returned array is owned by HarfBuzz
*    and should not be modified or freed.
*
* Since: 11.0.0
**/
const char **
hb_face_list_loaders ()
{
 return static_face_loader_list.get_unconst ();
}
#endif


/**
* hb_face_get_empty:
*
* Fetches the singleton empty face object.
*
* Return value: (transfer full): The empty face object
*
* Since: 0.9.2
**/
hb_face_t *
hb_face_get_empty ()
{
 return const_cast<hb_face_t *> (&Null (hb_face_t));
}


/**
* hb_face_reference: (skip)
* @face: A face object
*
* Increases the reference count on a face object.
*
* Return value: The @face object
*
* 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 object
*
* Decreases the reference count on a face object. When the
* reference count reaches zero, the face is destroyed,
* freeing all memory.
*
* Since: 0.9.2
**/
void
hb_face_destroy (hb_face_t *face)
{
 if (!hb_object_destroy (face)) return;

#ifndef HB_NO_SHAPER
 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);
   hb_free (node);
   node = next;
 }
#endif

 face->data.fini ();
 face->table.fini ();

 if (face->get_table_tags_destroy)
   face->get_table_tags_destroy (face->get_table_tags_user_data);

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

 hb_free (face);
}

/**
* hb_face_set_user_data: (skip)
* @face: A face object
* @key: The user-data key to set
* @data: A pointer to the user data
* @destroy: (nullable): A callback to call when @data is not needed anymore
* @replace: Whether to replace an existing data with the same key
*
* Attaches a user-data key/data pair to the given face object.
*
* Return value: `true` if success, `false` otherwise
*
* 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 object
* @key: The user-data key to query
*
* Fetches the user data associated with the specified key,
* attached to the specified face object.
*
* Return value: (transfer none): A pointer to the user data
*
* Since: 0.9.2
**/
void *
hb_face_get_user_data (const 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 object
*
* Makes the given face object immutable.
*
* Since: 0.9.2
**/
void
hb_face_make_immutable (hb_face_t *face)
{
 if (hb_object_is_immutable (face))
   return;

 hb_object_make_immutable (face);
}

/**
* hb_face_is_immutable:
* @face: A face object
*
* Tests whether the given face object is immutable.
*
* Return value: `true` is @face is immutable, `false` otherwise
*
* Since: 0.9.2
**/
hb_bool_t
hb_face_is_immutable (hb_face_t *face)
{
 return hb_object_is_immutable (face);
}


/**
* hb_face_reference_table:
* @face: A face object
* @tag: The #hb_tag_t of the table to query
*
* Fetches a reference to the specified table within
* the specified face. Returns an empty blob if referencing table data is not
* possible.
*
* Return value: (transfer full): A pointer to the @tag table within @face
*
* Since: 0.9.2
**/
hb_blob_t *
hb_face_reference_table (const hb_face_t *face,
		 hb_tag_t tag)
{
 if (unlikely (tag == HB_TAG_NONE))
   return hb_blob_get_empty ();

 return face->reference_table (tag);
}

/**
* hb_face_reference_blob:
* @face: A face object
*
* Fetches a pointer to the binary blob that contains the specified face.
* If referencing the face data is not possible, this function creates a blob
* out of individual table blobs if hb_face_get_table_tags() works with this
* face, otherwise it returns an empty blob.
*
* Return value: (transfer full): A pointer to the blob for @face
*
* Since: 0.9.2
**/
hb_blob_t *
hb_face_reference_blob (hb_face_t *face)
{
 hb_blob_t *blob = face->reference_table (HB_TAG_NONE);

 if (blob == hb_blob_get_empty ())
 {
   // If referencing the face blob is not possible (e.g. not implemented by the
   // font functions), use face builder to create a blob out of individual
   // table blobs.
   unsigned total_count = hb_face_get_table_tags (face, 0, nullptr, nullptr);
   if (total_count)
   {
     hb_tag_t tags[64];
     unsigned count = ARRAY_LENGTH (tags);
     hb_face_t* builder = hb_face_builder_create ();

     for (unsigned offset = 0; offset < total_count; offset += count)
     {
       hb_face_get_table_tags (face, offset, &count, tags);
if (unlikely (!count))
  break; // Allocation error
       for (unsigned i = 0; i < count; i++)
       {
  if (unlikely (!tags[i]))
    continue;
  hb_blob_t *table = hb_face_reference_table (face, tags[i]);
  hb_face_builder_add_table (builder, tags[i], table);
  hb_blob_destroy (table);
       }
     }

     blob = hb_face_reference_blob (builder);
     hb_face_destroy (builder);
   }
 }

 return blob;
}

/**
* hb_face_set_index:
* @face: A face object
* @index: The index to assign
*
* Assigns the specified face-index to @face. Fails if the
* face is immutable.
*
* <note>Note: changing the index has no effect on the face itself
* This only changes the value returned by hb_face_get_index().</note>
*
* Since: 0.9.2
**/
void
hb_face_set_index (hb_face_t    *face,
	   unsigned int  index)
{
 if (hb_object_is_immutable (face))
   return;

 face->index = index;
}

/**
* hb_face_get_index:
* @face: A face object
*
* Fetches the face-index corresponding to the given face.
*
* <note>Note: face indices within a collection are zero-based.</note>
*
* Return value: The index of @face.
*
* Since: 0.9.2
**/
unsigned int
hb_face_get_index (const hb_face_t *face)
{
 return face->index;
}

/**
* hb_face_set_upem:
* @face: A face object
* @upem: The units-per-em value to assign
*
* Sets the units-per-em (upem) for a face object to the specified value.
*
* This API is used in rare circumstances.
*
* Since: 0.9.2
**/
void
hb_face_set_upem (hb_face_t    *face,
	  unsigned int  upem)
{
 if (hb_object_is_immutable (face))
   return;

 face->upem = upem;
}

/**
* hb_face_get_upem:
* @face: A face object
*
* Fetches the units-per-em (UPEM) value of the specified face object.
*
* Typical UPEM values for fonts are 1000, or 2048, but any value
* in between 16 and 16,384 is allowed for OpenType fonts.
*
* Return value: The upem value of @face
*
* Since: 0.9.2
**/
unsigned int
hb_face_get_upem (const hb_face_t *face)
{
 return face->get_upem ();
}

/**
* hb_face_set_glyph_count:
* @face: A face object
* @glyph_count: The glyph-count value to assign
*
* Sets the glyph count for a face object to the specified value.
*
* This API is used in rare circumstances.
*
* Since: 0.9.7
**/
void
hb_face_set_glyph_count (hb_face_t    *face,
		 unsigned int  glyph_count)
{
 if (hb_object_is_immutable (face))
   return;

 face->num_glyphs = glyph_count;
}

/**
* hb_face_get_glyph_count:
* @face: A face object
*
* Fetches the glyph-count value of the specified face object.
*
* Return value: The glyph-count value of @face
*
* Since: 0.9.7
**/
unsigned int
hb_face_get_glyph_count (const hb_face_t *face)
{
 return face->get_num_glyphs ();
}

/**
* hb_face_set_get_table_tags_func:
* @face: A face object
* @func: (closure user_data) (destroy destroy) (scope notified): The table-tag-fetching function
* @user_data: A pointer to the user data, to be destroyed by @destroy when not needed anymore
* @destroy: (nullable): A callback to call when @func is not needed anymore
*
* Sets the table-tag-fetching function for the specified face object.
*
* Since: 10.0.0
*/
HB_EXTERN void
hb_face_set_get_table_tags_func (hb_face_t *face,
			 hb_get_table_tags_func_t func,
			 void                    *user_data,
			 hb_destroy_func_t        destroy)
{
 if (hb_object_is_immutable (face))
 {
   if (destroy)
     destroy (user_data);
   return;
 }

 if (face->get_table_tags_destroy)
   face->get_table_tags_destroy (face->get_table_tags_user_data);

 face->get_table_tags_func = func;
 face->get_table_tags_user_data = user_data;
 face->get_table_tags_destroy = destroy;
}

/**
* hb_face_get_table_tags:
* @face: A face object
* @start_offset: The index of first table tag to retrieve
* @table_count: (inout): Input = the maximum number of table tags to return;
*                Output = the actual number of table tags returned (may be zero)
* @table_tags: (out) (array length=table_count): The array of table tags found
*
* Fetches a list of all table tags for a face, if possible. The list returned will
* begin at the offset provided
*
* Return value: Total number of tables, or zero if it is not possible to list
*
* Since: 1.6.0
**/
unsigned int
hb_face_get_table_tags (const hb_face_t *face,
		unsigned int  start_offset,
		unsigned int *table_count, /* IN/OUT */
		hb_tag_t     *table_tags /* OUT */)
{
 if (!face->get_table_tags_func)
 {
   if (table_count)
     *table_count = 0;
   return 0;
 }

 return face->get_table_tags_func (face, start_offset, table_count, table_tags, face->get_table_tags_user_data);
}


/*
* Character set.
*/


#ifndef HB_NO_FACE_COLLECT_UNICODES
/**
* hb_face_collect_unicodes:
* @face: A face object
* @out: (out): The set to add Unicode characters to
*
* Collects all of the Unicode characters covered by @face and adds
* them to the #hb_set_t set @out.
*
* Since: 1.9.0
*/
void
hb_face_collect_unicodes (hb_face_t *face,
		  hb_set_t  *out)
{
 face->table.cmap->collect_unicodes (out, face->get_num_glyphs ());
}
/**
* hb_face_collect_nominal_glyph_mapping:
* @face: A face object
* @mapping: (out): The map to add Unicode-to-glyph mapping to
* @unicodes: (nullable) (out): The set to add Unicode characters to, or `NULL`
*
* Collects the mapping from Unicode characters to nominal glyphs of the @face,
* and optionally all of the Unicode characters covered by @face.
*
* Since: 7.0.0
*/
void
hb_face_collect_nominal_glyph_mapping (hb_face_t *face,
			       hb_map_t  *mapping,
			       hb_set_t  *unicodes)
{
 hb_set_t stack_unicodes;
 if (!unicodes)
   unicodes = &stack_unicodes;
 face->table.cmap->collect_mapping (unicodes, mapping, face->get_num_glyphs ());
}
/**
* hb_face_collect_variation_selectors:
* @face: A face object
* @out: (out): The set to add Variation Selector characters to
*
* Collects all Unicode "Variation Selector" characters covered by @face and adds
* them to the #hb_set_t set @out.
*
* Since: 1.9.0
*/
void
hb_face_collect_variation_selectors (hb_face_t *face,
			     hb_set_t  *out)
{
 face->table.cmap->collect_variation_selectors (out);
}
/**
* hb_face_collect_variation_unicodes:
* @face: A face object
* @variation_selector: The Variation Selector to query
* @out: (out): The set to add Unicode characters to
*
* Collects all Unicode characters for @variation_selector covered by @face and adds
* them to the #hb_set_t set @out.
*
* Since: 1.9.0
*/
void
hb_face_collect_variation_unicodes (hb_face_t *face,
			    hb_codepoint_t variation_selector,
			    hb_set_t  *out)
{
 face->table.cmap->collect_variation_unicodes (variation_selector, out);
}
#endif