kc3-lang/harfbuzz/src/graph/classdef-graph.hh

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• Hash : ff326fbe
  Author :
  Date : 2023-05-29T21:31:01
  

  [repacker] check the result of add_buffer() in other places where it's called.
  

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• src/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 ();
      if (!class_def_copy.arrayZ) return false;
      // Give ownership to the context, it will cleanup the buffer.
      if (!c.add_buffer ((char *) class_def_copy.arrayZ))
      {
        hb_free ((char *) class_def_copy.arrayZ);
        return false;
      }
  
      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
  

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