src/graph/classdef-graph.hh - third_party/harfbuzz - Git at Google

 /*
  * Copyright © 2022  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
  */

 #include "graph.hh"
 #include "../hb-ot-layout-common.hh"

 #ifndef GRAPH_CLASSDEF_GRAPH_HH
 #define GRAPH_CLASSDEF_GRAPH_HH

 namespace graph {

 struct ClassDefFormat1 : public OT::ClassDefFormat1_3<SmallTypes>
 {
   bool sanitize (graph_t::vertex_t& vertex) const
   {
     int64_t vertex_len = vertex.obj.tail - vertex.obj.head;
     constexpr unsigned min_size = OT::ClassDefFormat1_3<SmallTypes>::min_size;
     if (vertex_len < min_size) return false;
     return vertex_len >= min_size + classValue.get_size () - classValue.len.get_size ();
   }
 };

 struct ClassDefFormat2 : public OT::ClassDefFormat2_4<SmallTypes>
 {
   bool sanitize (graph_t::vertex_t& vertex) const
   {
     int64_t vertex_len = vertex.obj.tail - vertex.obj.head;
     constexpr unsigned min_size = OT::ClassDefFormat2_4<SmallTypes>::min_size;
     if (vertex_len < min_size) return false;
     return vertex_len >= min_size + rangeRecord.get_size () - rangeRecord.len.get_size ();
   }
 };

 struct ClassDef : public OT::ClassDef
 {
   template<typename It>
   static bool add_class_def (gsubgpos_graph_context_t& c,
                              unsigned parent_id,
                              unsigned link_position,
                              It glyph_and_class,
                              unsigned max_size)
   {
     unsigned class_def_prime_id = c.graph.new_node (nullptr, nullptr);
     auto& class_def_prime_vertex = c.graph.vertices_[class_def_prime_id];
     if (!make_class_def (c, glyph_and_class, class_def_prime_id, max_size))
       return false;

     auto* class_def_link = c.graph.vertices_[parent_id].obj.real_links.push ();
     class_def_link->width = SmallTypes::size;
     class_def_link->objidx = class_def_prime_id;
     class_def_link->position = link_position;
     class_def_prime_vertex.parents.push (parent_id);

     return true;
   }

   template<typename It>
   static bool make_class_def (gsubgpos_graph_context_t& c,
                               It glyph_and_class,
                               unsigned dest_obj,
                               unsigned max_size)
   {
     char* buffer = (char*) hb_calloc (1, max_size);
     hb_serialize_context_t serializer (buffer, max_size);
     OT::ClassDef_serialize (&serializer, glyph_and_class);
     serializer.end_serialize ();
     if (serializer.in_error ())
     {
       hb_free (buffer);
       return false;
     }

     hb_bytes_t class_def_copy = serializer.copy_bytes ();
     c.add_buffer ((char *) class_def_copy.arrayZ); // Give ownership to the context, it will cleanup the buffer.

     auto& obj = c.graph.vertices_[dest_obj].obj;
     obj.head = (char *) class_def_copy.arrayZ;
     obj.tail = obj.head + class_def_copy.length;

     hb_free (buffer);
     return true;
   }

   bool sanitize (graph_t::vertex_t& vertex) const
   {
     int64_t vertex_len = vertex.obj.tail - vertex.obj.head;
     if (vertex_len < OT::ClassDef::min_size) return false;
     switch (u.format)
     {
     case 1: return ((ClassDefFormat1*)this)->sanitize (vertex);
     case 2: return ((ClassDefFormat2*)this)->sanitize (vertex);
 #ifndef HB_NO_BEYOND_64K
     // Not currently supported
     case 3:
     case 4:
 #endif
     default: return false;
     }
   }
 };


 struct class_def_size_estimator_t
 {
   template<typename It>
   class_def_size_estimator_t (It glyph_and_class)
       : gids_consecutive (true), num_ranges_per_class (), glyphs_per_class ()
   {
     unsigned last_gid = (unsigned) -1;
     for (auto p : + glyph_and_class)
     {
       unsigned gid = p.first;
       unsigned klass = p.second;

       if (last_gid != (unsigned) -1 && gid != last_gid + 1)
         gids_consecutive = false;
       last_gid = gid;

       hb_set_t* glyphs;
       if (glyphs_per_class.has (klass, &glyphs) && glyphs) {
         glyphs->add (gid);
         continue;
       }

       hb_set_t new_glyphs;
       new_glyphs.add (gid);
       glyphs_per_class.set (klass, std::move (new_glyphs));
     }

     if (in_error ()) return;

     for (unsigned klass : glyphs_per_class.keys ())
     {
       if (!klass) continue; // class 0 doesn't get encoded.

       const hb_set_t& glyphs = glyphs_per_class.get (klass);
       hb_codepoint_t start = HB_SET_VALUE_INVALID;
       hb_codepoint_t end = HB_SET_VALUE_INVALID;

       unsigned count = 0;
       while (glyphs.next_range (&start, &end))
         count++;

       num_ranges_per_class.set (klass, count);
     }
   }

   // Incremental increase in the Coverage and ClassDef table size
   // (worst case) if all glyphs associated with 'klass' were added.
   unsigned incremental_coverage_size (unsigned klass) const
   {
     // Coverage takes 2 bytes per glyph worst case,
     return 2 * glyphs_per_class.get (klass).get_population ();
   }

   // Incremental increase in the Coverage and ClassDef table size
   // (worst case) if all glyphs associated with 'klass' were added.
   unsigned incremental_class_def_size (unsigned klass) const
   {
     // ClassDef takes 6 bytes per range
     unsigned class_def_2_size = 6 * num_ranges_per_class.get (klass);
     if (gids_consecutive)
     {
       // ClassDef1 takes 2 bytes per glyph, but only can be used
       // when gids are consecutive.
       return hb_min (2 * glyphs_per_class.get (klass).get_population (), class_def_2_size);
     }

     return class_def_2_size;
   }

   bool in_error ()
   {
     if (num_ranges_per_class.in_error ()) return true;
     if (glyphs_per_class.in_error ()) return true;

     for (const hb_set_t& s : glyphs_per_class.values ())
     {
       if (s.in_error ()) return true;
     }
     return false;
   }

  private:
   bool gids_consecutive;
   hb_hashmap_t<unsigned, unsigned> num_ranges_per_class;
   hb_hashmap_t<unsigned, hb_set_t> glyphs_per_class;
 };


 }

 #endif  // GRAPH_CLASSDEF_GRAPH_HH
	/*
	* Copyright © 2022 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
	*/

	#include "graph.hh"
	#include "../hb-ot-layout-common.hh"

	#ifndef GRAPH_CLASSDEF_GRAPH_HH
	#define GRAPH_CLASSDEF_GRAPH_HH

	namespace graph {

	struct ClassDefFormat1 : public OT::ClassDefFormat1_3<SmallTypes>
	{
	bool sanitize (graph_t::vertex_t& vertex) const
	{
	int64_t vertex_len = vertex.obj.tail - vertex.obj.head;
	constexpr unsigned min_size = OT::ClassDefFormat1_3<SmallTypes>::min_size;
	if (vertex_len < min_size) return false;
	return vertex_len >= min_size + classValue.get_size () - classValue.len.get_size ();
	}
	};

	struct ClassDefFormat2 : public OT::ClassDefFormat2_4<SmallTypes>
	{
	bool sanitize (graph_t::vertex_t& vertex) const
	{
	int64_t vertex_len = vertex.obj.tail - vertex.obj.head;
	constexpr unsigned min_size = OT::ClassDefFormat2_4<SmallTypes>::min_size;
	if (vertex_len < min_size) return false;
	return vertex_len >= min_size + rangeRecord.get_size () - rangeRecord.len.get_size ();
	}
	};

	struct ClassDef : public OT::ClassDef
	{
	template<typename It>
	static bool add_class_def (gsubgpos_graph_context_t& c,
	unsigned parent_id,
	unsigned link_position,
	It glyph_and_class,
	unsigned max_size)
	{
	unsigned class_def_prime_id = c.graph.new_node (nullptr, nullptr);
	auto& class_def_prime_vertex = c.graph.vertices_[class_def_prime_id];
	if (!make_class_def (c, glyph_and_class, class_def_prime_id, max_size))
	return false;

	auto* class_def_link = c.graph.vertices_[parent_id].obj.real_links.push ();
	class_def_link->width = SmallTypes::size;
	class_def_link->objidx = class_def_prime_id;
	class_def_link->position = link_position;
	class_def_prime_vertex.parents.push (parent_id);

	return true;
	}

	template<typename It>
	static bool make_class_def (gsubgpos_graph_context_t& c,
	It glyph_and_class,
	unsigned dest_obj,
	unsigned max_size)
	{
	char* buffer = (char*) hb_calloc (1, max_size);
	hb_serialize_context_t serializer (buffer, max_size);
	OT::ClassDef_serialize (&serializer, glyph_and_class);
	serializer.end_serialize ();
	if (serializer.in_error ())
	{
	hb_free (buffer);
	return false;
	}

	hb_bytes_t class_def_copy = serializer.copy_bytes ();
	c.add_buffer ((char *) class_def_copy.arrayZ); // Give ownership to the context, it will cleanup the buffer.

	auto& obj = c.graph.vertices_[dest_obj].obj;
	obj.head = (char *) class_def_copy.arrayZ;
	obj.tail = obj.head + class_def_copy.length;

	hb_free (buffer);
	return true;
	}

	bool sanitize (graph_t::vertex_t& vertex) const
	{
	int64_t vertex_len = vertex.obj.tail - vertex.obj.head;
	if (vertex_len < OT::ClassDef::min_size) return false;
	switch (u.format)
	{
	case 1: return ((ClassDefFormat1*)this)->sanitize (vertex);
	case 2: return ((ClassDefFormat2*)this)->sanitize (vertex);
	#ifndef HB_NO_BEYOND_64K
	// Not currently supported
	case 3:
	case 4:
	#endif
	default: return false;
	}
	}
	};


	struct class_def_size_estimator_t
	{
	template<typename It>
	class_def_size_estimator_t (It glyph_and_class)
	: gids_consecutive (true), num_ranges_per_class (), glyphs_per_class ()
	{
	unsigned last_gid = (unsigned) -1;
	for (auto p : + glyph_and_class)
	{
	unsigned gid = p.first;
	unsigned klass = p.second;

	if (last_gid != (unsigned) -1 && gid != last_gid + 1)
	gids_consecutive = false;
	last_gid = gid;

	hb_set_t* glyphs;
	if (glyphs_per_class.has (klass, &glyphs) && glyphs) {
	glyphs->add (gid);
	continue;
	}

	hb_set_t new_glyphs;
	new_glyphs.add (gid);
	glyphs_per_class.set (klass, std::move (new_glyphs));
	}

	if (in_error ()) return;

	for (unsigned klass : glyphs_per_class.keys ())
	{
	if (!klass) continue; // class 0 doesn't get encoded.

	const hb_set_t& glyphs = glyphs_per_class.get (klass);
	hb_codepoint_t start = HB_SET_VALUE_INVALID;
	hb_codepoint_t end = HB_SET_VALUE_INVALID;

	unsigned count = 0;
	while (glyphs.next_range (&start, &end))
	count++;

	num_ranges_per_class.set (klass, count);
	}
	}

	// Incremental increase in the Coverage and ClassDef table size
	// (worst case) if all glyphs associated with 'klass' were added.
	unsigned incremental_coverage_size (unsigned klass) const
	{
	// Coverage takes 2 bytes per glyph worst case,
	return 2 * glyphs_per_class.get (klass).get_population ();
	}

	// Incremental increase in the Coverage and ClassDef table size
	// (worst case) if all glyphs associated with 'klass' were added.
	unsigned incremental_class_def_size (unsigned klass) const
	{
	// ClassDef takes 6 bytes per range
	unsigned class_def_2_size = 6 * num_ranges_per_class.get (klass);
	if (gids_consecutive)
	{
	// ClassDef1 takes 2 bytes per glyph, but only can be used
	// when gids are consecutive.
	return hb_min (2 * glyphs_per_class.get (klass).get_population (), class_def_2_size);
	}

	return class_def_2_size;
	}

	bool in_error ()
	{
	if (num_ranges_per_class.in_error ()) return true;
	if (glyphs_per_class.in_error ()) return true;

	for (const hb_set_t& s : glyphs_per_class.values ())
	{
	if (s.in_error ()) return true;
	}
	return false;
	}

	private:
	bool gids_consecutive;
	hb_hashmap_t<unsigned, unsigned> num_ranges_per_class;
	hb_hashmap_t<unsigned, hb_set_t> glyphs_per_class;
	};


	}

	#endif // GRAPH_CLASSDEF_GRAPH_HH