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

 /*
  * Copyright © 2018  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.
  *
  * Google Author(s): Garret Rieger, Rod Sheeter, Behdad Esfahbod
  */

 #include "hb-private.hh"
 #include "hb-object-private.hh"
 #include "hb-open-type-private.hh"

 #include "hb-subset-glyf.hh"
 #include "hb-subset-private.hh"
 #include "hb-subset-plan.hh"

 #include "hb-open-file-private.hh"
 #include "hb-ot-cmap-table.hh"
 #include "hb-ot-glyf-table.hh"
 #include "hb-ot-hdmx-table.hh"
 #include "hb-ot-head-table.hh"
 #include "hb-ot-hhea-table.hh"
 #include "hb-ot-hmtx-table.hh"
 #include "hb-ot-maxp-table.hh"
 #include "hb-ot-os2-table.hh"


 #ifndef HB_NO_VISIBILITY
 const void * const OT::_hb_NullPool[HB_NULL_POOL_SIZE / sizeof (void *)] = {};
 #endif


 struct hb_subset_profile_t {
   hb_object_header_t header;
   ASSERT_POD ();
 };

 /**
  * hb_subset_profile_create:
  *
  * Return value: New profile with default settings.
  *
  * Since: 1.8.0
  **/
 hb_subset_profile_t *
 hb_subset_profile_create ()
 {
   return hb_object_create<hb_subset_profile_t>();
 }

 /**
  * hb_subset_profile_destroy:
  *
  * Since: 1.8.0
  **/
 void
 hb_subset_profile_destroy (hb_subset_profile_t *profile)
 {
   if (!hb_object_destroy (profile)) return;

   free (profile);
 }

 template<typename TableType>
 static bool
 _subset (hb_subset_plan_t *plan)
 {
   OT::Sanitizer<TableType> sanitizer;

   hb_blob_t *source_blob = sanitizer.sanitize (plan->source->reference_table (TableType::tableTag));
   const TableType *table = OT::Sanitizer<TableType>::lock_instance (source_blob);

   hb_bool_t result = false;
   if (table != &OT::Null(TableType))
     result = table->subset(plan);

   hb_blob_destroy (source_blob);
   hb_tag_t tag = TableType::tableTag;
   DEBUG_MSG(SUBSET, nullptr, "OT::%c%c%c%c::subset %s", HB_UNTAG(tag), result ? "success" : "FAILED!");
   return result;
 }


 /*
  * A face that has add_table().
  */

 struct hb_subset_face_data_t
 {
   struct table_entry_t
   {
     inline int cmp (const hb_tag_t *t) const
     {
       if (*t < tag) return -1;
       if (*t > tag) return -1;
       return 0;
     }

     hb_tag_t   tag;
     hb_blob_t *blob;
   };

   hb_prealloced_array_t<table_entry_t, 32> tables;
 };

 static hb_subset_face_data_t *
 _hb_subset_face_data_create (void)
 {
   hb_subset_face_data_t *data = (hb_subset_face_data_t *) calloc (1, sizeof (hb_subset_face_data_t));
   if (unlikely (!data))
     return nullptr;

   return data;
 }

 static void
 _hb_subset_face_data_destroy (void *user_data)
 {
   hb_subset_face_data_t *data = (hb_subset_face_data_t *) user_data;

   for (int i = 0; i < data->tables.len; i++)
     hb_blob_destroy (data->tables[i].blob);

   data->tables.finish ();

   free (data);
 }

 static hb_blob_t *
 _hb_subset_face_data_reference_blob (hb_subset_face_data_t *data)
 {

   unsigned int table_count = data->tables.len;
   unsigned int face_length = table_count * 16 + 12;

   for (unsigned int i = 0; i < table_count; i++)
     face_length += _hb_ceil_to_4 (hb_blob_get_length (data->tables.array[i].blob));

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

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

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

   OT::Supplier<hb_tag_t>    tags_supplier  (&data->tables[0].tag, table_count, sizeof (data->tables[0]));
   OT::Supplier<hb_blob_t *> blobs_supplier (&data->tables[0].blob, table_count, sizeof (data->tables[0]));
   bool ret = f->serialize_single (&c,
 				  sfnt_tag,
 				  tags_supplier,
 				  blobs_supplier,
 				  table_count);

   c.end_serialize ();

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

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

 static hb_blob_t *
 _hb_subset_face_reference_table (hb_face_t *face, hb_tag_t tag, void *user_data)
 {
   hb_subset_face_data_t *data = (hb_subset_face_data_t *) user_data;

   if (!tag)
     return _hb_subset_face_data_reference_blob (data);

   hb_subset_face_data_t::table_entry_t *entry = data->tables.lsearch (tag);
   if (entry)
     return hb_blob_reference (entry->blob);

   return nullptr;
 }

 /* TODO: Move this to hb-face.h and rename to hb_face_builder_create()
  * with hb_face_builder_add_table(). */
 hb_face_t *
 hb_subset_face_create (void)
 {
   hb_subset_face_data_t *data = _hb_subset_face_data_create ();
   if (unlikely (!data)) return hb_face_get_empty ();

   return hb_face_create_for_tables (_hb_subset_face_reference_table,
 				    data,
 				    _hb_subset_face_data_destroy);
 }

 hb_bool_t
 hb_subset_face_add_table (hb_face_t *face, hb_tag_t tag, hb_blob_t *blob)
 {
   if (unlikely (face->destroy != _hb_subset_face_data_destroy))
     return false;

   hb_subset_face_data_t *data = (hb_subset_face_data_t *) face->user_data;
   hb_subset_face_data_t::table_entry_t *entry = data->tables.push ();
   if (unlikely (!entry))
     return false;

   entry->tag = tag;
   entry->blob = hb_blob_reference (blob);

   return true;
 }

 static bool
 _subset_table (hb_subset_plan_t *plan,
                hb_tag_t          tag)
 {
   DEBUG_MSG(SUBSET, nullptr, "begin subset %c%c%c%c", HB_UNTAG(tag));
   bool result = true;
   switch (tag) {
     case HB_OT_TAG_glyf:
       result = _subset<const OT::glyf> (plan);
       break;
     case HB_OT_TAG_hdmx:
       result = _subset<const OT::hdmx> (plan);
       break;
     case HB_OT_TAG_head:
       // SKIP head, it's handled by glyf
       result = true;
       break;
     case HB_OT_TAG_hhea:
       // SKIP hhea, it's handled by hmtx
       return true;
     case HB_OT_TAG_hmtx:
       result = _subset<const OT::hmtx> (plan);
       break;
     case HB_OT_TAG_maxp:
       result = _subset<const OT::maxp> (plan);
       break;
     case HB_OT_TAG_loca:
       // SKIP loca, it's handle by glyf
       return true;
     case HB_OT_TAG_cmap:
       result = _subset<const OT::cmap> (plan);
       break;
     case HB_OT_TAG_os2:
       result = _subset<const OT::os2> (plan);
       break;
     default:
       hb_blob_t *source_table = hb_face_reference_table(plan->source, tag);
       if (likely (source_table))
         result = hb_subset_plan_add_table(plan, tag, source_table);
       else
         result = false;
       hb_blob_destroy (source_table);
       break;
   }
   DEBUG_MSG(SUBSET, nullptr, "subset %c%c%c%c %s", HB_UNTAG(tag), result ? "ok" : "FAILED");
   return result;
 }

 static bool
 _should_drop_table(hb_tag_t tag)
 {
     switch (tag) {
       case HB_TAG ('G', 'D', 'E', 'F'): /* temporary */
       case HB_TAG ('G', 'P', 'O', 'S'): /* temporary */
       case HB_TAG ('G', 'S', 'U', 'B'): /* temporary */
       case HB_TAG ('D', 'S', 'I', 'G'):
         return true;
       default:
         return false;
   }
 }

 /**
  * hb_subset:
  * @source: font face data to be subset.
  * @profile: profile to use for the subsetting.
  * @input: input to use for the subsetting.
  *
  * Subsets a font according to provided profile and input.
  **/
 hb_face_t *
 hb_subset (hb_face_t *source,
            hb_subset_profile_t *profile,
            hb_subset_input_t *input)
 {
   if (unlikely (!profile || !input || !source)) return hb_face_get_empty();

   hb_subset_plan_t *plan = hb_subset_plan_create (source, profile, input);

   hb_tag_t table_tags[32];
   unsigned int offset = 0, count;
   bool success = true;
   do {
     count = ARRAY_LENGTH (table_tags);
     hb_face_get_table_tags (source, offset, &count, table_tags);
     for (unsigned int i = 0; i < count; i++)
     {
       hb_tag_t tag = table_tags[i];
       if (_should_drop_table(tag))
       {
         DEBUG_MSG(SUBSET, nullptr, "drop %c%c%c%c", HB_UNTAG(tag));
         continue;
       }
       success = success && _subset_table (plan, tag);
     }
   } while (count == ARRAY_LENGTH (table_tags));

   hb_face_t *result = success ? hb_face_reference(plan->dest) : hb_face_get_empty();
   hb_subset_plan_destroy (plan);
   return result;
 }
	/*
	* Copyright © 2018 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.
	*
	* Google Author(s): Garret Rieger, Rod Sheeter, Behdad Esfahbod
	*/

	#include "hb-private.hh"
	#include "hb-object-private.hh"
	#include "hb-open-type-private.hh"

	#include "hb-subset-glyf.hh"
	#include "hb-subset-private.hh"
	#include "hb-subset-plan.hh"

	#include "hb-open-file-private.hh"
	#include "hb-ot-cmap-table.hh"
	#include "hb-ot-glyf-table.hh"
	#include "hb-ot-hdmx-table.hh"
	#include "hb-ot-head-table.hh"
	#include "hb-ot-hhea-table.hh"
	#include "hb-ot-hmtx-table.hh"
	#include "hb-ot-maxp-table.hh"
	#include "hb-ot-os2-table.hh"


	#ifndef HB_NO_VISIBILITY
	const void * const OT::_hb_NullPool[HB_NULL_POOL_SIZE / sizeof (void *)] = {};
	#endif


	struct hb_subset_profile_t {
	hb_object_header_t header;
	ASSERT_POD ();
	};

	/**
	* hb_subset_profile_create:
	*
	* Return value: New profile with default settings.
	*
	* Since: 1.8.0
	**/
	hb_subset_profile_t *
	hb_subset_profile_create ()
	{
	return hb_object_create<hb_subset_profile_t>();
	}

	/**
	* hb_subset_profile_destroy:
	*
	* Since: 1.8.0
	**/
	void
	hb_subset_profile_destroy (hb_subset_profile_t *profile)
	{
	if (!hb_object_destroy (profile)) return;

	free (profile);
	}

	template<typename TableType>
	static bool
	_subset (hb_subset_plan_t *plan)
	{
	OT::Sanitizer<TableType> sanitizer;

	hb_blob_t *source_blob = sanitizer.sanitize (plan->source->reference_table (TableType::tableTag));
	const TableType *table = OT::Sanitizer<TableType>::lock_instance (source_blob);

	hb_bool_t result = false;
	if (table != &OT::Null(TableType))
	result = table->subset(plan);

	hb_blob_destroy (source_blob);
	hb_tag_t tag = TableType::tableTag;
	DEBUG_MSG(SUBSET, nullptr, "OT::%c%c%c%c::subset %s", HB_UNTAG(tag), result ? "success" : "FAILED!");
	return result;
	}


	/*
	* A face that has add_table().
	*/

	struct hb_subset_face_data_t
	{
	struct table_entry_t
	{
	inline int cmp (const hb_tag_t *t) const
	{
	if (*t < tag) return -1;
	if (*t > tag) return -1;
	return 0;
	}

	hb_tag_t tag;
	hb_blob_t *blob;
	};

	hb_prealloced_array_t<table_entry_t, 32> tables;
	};

	static hb_subset_face_data_t *
	_hb_subset_face_data_create (void)
	{
	hb_subset_face_data_t data = (hb_subset_face_data_t ) calloc (1, sizeof (hb_subset_face_data_t));
	if (unlikely (!data))
	return nullptr;

	return data;
	}

	static void
	_hb_subset_face_data_destroy (void *user_data)
	{
	hb_subset_face_data_t data = (hb_subset_face_data_t ) user_data;

	for (int i = 0; i < data->tables.len; i++)
	hb_blob_destroy (data->tables[i].blob);

	data->tables.finish ();

	free (data);
	}

	static hb_blob_t *
	_hb_subset_face_data_reference_blob (hb_subset_face_data_t *data)
	{

	unsigned int table_count = data->tables.len;
	unsigned int face_length = table_count * 16 + 12;

	for (unsigned int i = 0; i < table_count; i++)
	face_length += _hb_ceil_to_4 (hb_blob_get_length (data->tables.array[i].blob));

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

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

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

	OT::Supplier<hb_tag_t> tags_supplier (&data->tables[0].tag, table_count, sizeof (data->tables[0]));
	OT::Supplier<hb_blob_t *> blobs_supplier (&data->tables[0].blob, table_count, sizeof (data->tables[0]));
	bool ret = f->serialize_single (&c,
	sfnt_tag,
	tags_supplier,
	blobs_supplier,
	table_count);

	c.end_serialize ();

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

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

	static hb_blob_t *
	_hb_subset_face_reference_table (hb_face_t face, hb_tag_t tag, void user_data)
	{
	hb_subset_face_data_t data = (hb_subset_face_data_t ) user_data;

	if (!tag)
	return _hb_subset_face_data_reference_blob (data);

	hb_subset_face_data_t::table_entry_t *entry = data->tables.lsearch (tag);
	if (entry)
	return hb_blob_reference (entry->blob);

	return nullptr;
	}

	/* TODO: Move this to hb-face.h and rename to hb_face_builder_create()
	* with hb_face_builder_add_table(). */
	hb_face_t *
	hb_subset_face_create (void)
	{
	hb_subset_face_data_t *data = _hb_subset_face_data_create ();
	if (unlikely (!data)) return hb_face_get_empty ();

	return hb_face_create_for_tables (_hb_subset_face_reference_table,
	data,
	_hb_subset_face_data_destroy);
	}

	hb_bool_t
	hb_subset_face_add_table (hb_face_t face, hb_tag_t tag, hb_blob_t blob)
	{
	if (unlikely (face->destroy != _hb_subset_face_data_destroy))
	return false;

	hb_subset_face_data_t data = (hb_subset_face_data_t ) face->user_data;
	hb_subset_face_data_t::table_entry_t *entry = data->tables.push ();
	if (unlikely (!entry))
	return false;

	entry->tag = tag;
	entry->blob = hb_blob_reference (blob);

	return true;
	}

	static bool
	_subset_table (hb_subset_plan_t *plan,
	hb_tag_t tag)
	{
	DEBUG_MSG(SUBSET, nullptr, "begin subset %c%c%c%c", HB_UNTAG(tag));
	bool result = true;
	switch (tag) {
	case HB_OT_TAG_glyf:
	result = _subset<const OT::glyf> (plan);
	break;
	case HB_OT_TAG_hdmx:
	result = _subset<const OT::hdmx> (plan);
	break;
	case HB_OT_TAG_head:
	// SKIP head, it's handled by glyf
	result = true;
	break;
	case HB_OT_TAG_hhea:
	// SKIP hhea, it's handled by hmtx
	return true;
	case HB_OT_TAG_hmtx:
	result = _subset<const OT::hmtx> (plan);
	break;
	case HB_OT_TAG_maxp:
	result = _subset<const OT::maxp> (plan);
	break;
	case HB_OT_TAG_loca:
	// SKIP loca, it's handle by glyf
	return true;
	case HB_OT_TAG_cmap:
	result = _subset<const OT::cmap> (plan);
	break;
	case HB_OT_TAG_os2:
	result = _subset<const OT::os2> (plan);
	break;
	default:
	hb_blob_t *source_table = hb_face_reference_table(plan->source, tag);
	if (likely (source_table))
	result = hb_subset_plan_add_table(plan, tag, source_table);
	else
	result = false;
	hb_blob_destroy (source_table);
	break;
	}
	DEBUG_MSG(SUBSET, nullptr, "subset %c%c%c%c %s", HB_UNTAG(tag), result ? "ok" : "FAILED");
	return result;
	}

	static bool
	_should_drop_table(hb_tag_t tag)
	{
	switch (tag) {
	case HB_TAG ('G', 'D', 'E', 'F'): /* temporary */
	case HB_TAG ('G', 'P', 'O', 'S'): /* temporary */
	case HB_TAG ('G', 'S', 'U', 'B'): /* temporary */
	case HB_TAG ('D', 'S', 'I', 'G'):
	return true;
	default:
	return false;
	}
	}

	/**
	* hb_subset:
	* @source: font face data to be subset.
	* @profile: profile to use for the subsetting.
	* @input: input to use for the subsetting.
	*
	* Subsets a font according to provided profile and input.
	**/
	hb_face_t *
	hb_subset (hb_face_t *source,
	hb_subset_profile_t *profile,
	hb_subset_input_t *input)
	{
	if (unlikely (!profile \|\| !input \|\| !source)) return hb_face_get_empty();

	hb_subset_plan_t *plan = hb_subset_plan_create (source, profile, input);

	hb_tag_t table_tags[32];
	unsigned int offset = 0, count;
	bool success = true;
	do {
	count = ARRAY_LENGTH (table_tags);
	hb_face_get_table_tags (source, offset, &count, table_tags);
	for (unsigned int i = 0; i < count; i++)
	{
	hb_tag_t tag = table_tags[i];
	if (_should_drop_table(tag))
	{
	DEBUG_MSG(SUBSET, nullptr, "drop %c%c%c%c", HB_UNTAG(tag));
	continue;
	}
	success = success && _subset_table (plan, tag);
	}
	} while (count == ARRAY_LENGTH (table_tags));

	hb_face_t *result = success ? hb_face_reference(plan->dest) : hb_face_get_empty();
	hb_subset_plan_destroy (plan);
	return result;
	}