tor-browser

hb-face-builder.cc (8285B)

---

/*
* 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-map.hh"
#include "hb-open-file.hh"
#include "hb-serialize.hh"


/*
* face-builder: A face that has add_table().
*/

struct face_table_info_t
{
 hb_blob_t* data;
 unsigned order;
};

struct hb_face_builder_data_t
{
 hb_hashmap_t<hb_tag_t, face_table_info_t> tables;
};

static int compare_entries (const void* pa, const void* pb)
{
 const auto& a = * (const hb_pair_t<hb_tag_t, face_table_info_t> *) pa;
 const auto& b = * (const hb_pair_t<hb_tag_t, face_table_info_t> *) pb;

 /* Order by blob size first (smallest to largest) and then table tag */

 if (a.second.order != b.second.order)
   return a.second.order < b.second.order ? -1 : +1;

 if (a.second.data->length != b.second.data->length)
   return a.second.data->length < b.second.data->length ? -1 : +1;

 return a.first < b.first ? -1 : a.first == b.first ? 0 : +1;
}

static hb_face_builder_data_t *
_hb_face_builder_data_create ()
{
 hb_face_builder_data_t *data = (hb_face_builder_data_t *) hb_calloc (1, sizeof (hb_face_builder_data_t));
 if (unlikely (!data))
   return nullptr;

 data->tables.init ();

 return data;
}

static void
_hb_face_builder_data_destroy (void *user_data)
{
 hb_face_builder_data_t *data = (hb_face_builder_data_t *) user_data;

 for (auto info : data->tables.values())
   hb_blob_destroy (info.data);

 data->tables.fini ();

 hb_free (data);
}

static hb_blob_t *
_hb_face_builder_data_reference_blob (hb_face_builder_data_t *data)
{

 unsigned int table_count = data->tables.get_population ();
 unsigned int face_length = table_count * 16 + 12;

 for (auto info : data->tables.values())
   face_length += hb_ceil_to_4 (hb_blob_get_length (info.data));

 char *buf = (char *) hb_malloc (face_length);
 if (unlikely (!buf))
   return nullptr;

 hb_serialize_context_t c (buf, face_length);
 c.propagate_error (data->tables);
 OT::OpenTypeFontFile *f = c.start_serialize<OT::OpenTypeFontFile> ();

 bool is_cff = (data->tables.has (HB_TAG ('C','F','F',' '))
                || data->tables.has (HB_TAG ('C','F','F','2')));
 hb_tag_t sfnt_tag = is_cff ? OT::OpenTypeFontFile::CFFTag : OT::OpenTypeFontFile::TrueTypeTag;

 // Sort the tags so that produced face is deterministic.
 hb_vector_t<hb_pair_t <hb_tag_t, face_table_info_t>> sorted_entries;
 data->tables.iter () | hb_sink (sorted_entries);
 if (unlikely (sorted_entries.in_error ()))
 {
   hb_free (buf);
   return nullptr;
 }

 sorted_entries.qsort (compare_entries);

 bool ret = f->serialize_single (&c,
                                 sfnt_tag,
                                 + sorted_entries.iter()
                                 | hb_map ([&] (hb_pair_t<hb_tag_t, face_table_info_t> _) {
                                   return hb_pair_t<hb_tag_t, hb_blob_t*> (_.first, _.second.data);
                                 }));

 c.end_serialize ();

 if (unlikely (!ret))
 {
   hb_free (buf);
   return nullptr;
 }

 return hb_blob_create (buf, face_length, HB_MEMORY_MODE_WRITABLE, buf, hb_free);
}

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

 if (!tag)
   return _hb_face_builder_data_reference_blob (data);

 return hb_blob_reference (data->tables[tag].data);
}

static unsigned
_hb_face_builder_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_builder_data_t *data = (hb_face_builder_data_t *) user_data;

 unsigned population = data->tables.get_population ();

 if (!table_count)
   return population;

 if (unlikely (start_offset >= population))
 {
   *table_count = 0;
   return population;
 }

 // Sort the tags.
 hb_vector_t<hb_tag_t> sorted_tags;
 data->tables.keys () | hb_sink (sorted_tags);
 if (unlikely (sorted_tags.in_error ()))
 {
   // Not much to do...
 }
 sorted_tags.qsort ([] (const void* a, const void* b) {
   return * (hb_tag_t *) a <  * (hb_tag_t *) b ? -1 :
   * (hb_tag_t *) a == * (hb_tag_t *) b ?  0 :
                                          +1;
 });

 auto array = sorted_tags.as_array ().sub_array (start_offset, table_count);
 auto out = hb_array (table_tags, *table_count);

 + array.iter ()
 | hb_sink (out)
 ;

 return population;
}


/**
* hb_face_builder_create:
*
* Creates a #hb_face_t that can be used with hb_face_builder_add_table().
* After tables are added to the face, it can be compiled to a binary
* font file by calling hb_face_reference_blob().
*
* Return value: (transfer full): New face.
*
* Since: 1.9.0
**/
hb_face_t *
hb_face_builder_create ()
{
 hb_face_builder_data_t *data = _hb_face_builder_data_create ();
 if (unlikely (!data)) return hb_face_get_empty ();

 hb_face_t *face = hb_face_create_for_tables (_hb_face_builder_reference_table,
				       data,
				       _hb_face_builder_data_destroy);

 hb_face_set_get_table_tags_func (face,
			   _hb_face_builder_get_table_tags,
			   data,
			   nullptr);

 return face;
}

/**
* hb_face_builder_add_table:
* @face: A face object created with hb_face_builder_create()
* @tag: The #hb_tag_t of the table to add
* @blob: The blob containing the table data to add
*
* Add table for @tag with data provided by @blob to the face.  @face must
* be created using hb_face_builder_create().
*
* Since: 1.9.0
**/
hb_bool_t
hb_face_builder_add_table (hb_face_t *face, hb_tag_t tag, hb_blob_t *blob)
{
 if (unlikely (face->destroy != (hb_destroy_func_t) _hb_face_builder_data_destroy))
   return false;

 if (tag == HB_MAP_VALUE_INVALID)
   return false;

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

 hb_blob_t* previous = data->tables.get (tag).data;
 if (!data->tables.set (tag, face_table_info_t {hb_blob_reference (blob), (unsigned) -1}))
 {
   hb_blob_destroy (blob);
   return false;
 }

 hb_blob_destroy (previous);
 return true;
}

/**
* hb_face_builder_sort_tables:
* @face: A face object created with hb_face_builder_create()
* @tags: (array zero-terminated=1): ordered list of table tags terminated by
*   %HB_TAG_NONE
*
* Set the ordering of tables for serialization. Any tables not
* specified in the tags list will be ordered after the tables in
* tags, ordered by the default sort ordering.
*
* Since: 5.3.0
**/
void
hb_face_builder_sort_tables (hb_face_t *face,
                            const hb_tag_t  *tags)
{
 if (unlikely (face->destroy != (hb_destroy_func_t) _hb_face_builder_data_destroy))
   return;

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

 // Sort all unspecified tables after any specified tables.
 for (auto& info : data->tables.values_ref())
   info.order = (unsigned) -1;

 signed order = 0;
 for (const hb_tag_t* tag = tags;
      *tag;
      tag++)
 {
   face_table_info_t* info;
   if (!data->tables.has (*tag, &info)) continue;
   info->order = order++;
 }
}