217 lines
6.6 KiB
C++
217 lines
6.6 KiB
C++
/*
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* Copyright © 2022 Google, Inc.
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*
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* This is part of HarfBuzz, a text shaping library.
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*
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* Permission is hereby granted, without written agreement and without
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* license or royalty fees, to use, copy, modify, and distribute this
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* software and its documentation for any purpose, provided that the
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* above copyright notice and the following two paragraphs appear in
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* all copies of this software.
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*
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* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
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* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
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* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
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* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
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* DAMAGE.
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*
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* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
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* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
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* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
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* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
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*
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* Google Author(s): Garret Rieger
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*/
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#include "graph.hh"
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#include "../hb-ot-layout-common.hh"
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#ifndef GRAPH_CLASSDEF_GRAPH_HH
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#define GRAPH_CLASSDEF_GRAPH_HH
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namespace graph {
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struct ClassDefFormat1 : public OT::ClassDefFormat1_3<SmallTypes>
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{
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bool sanitize (graph_t::vertex_t& vertex) const
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{
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int64_t vertex_len = vertex.obj.tail - vertex.obj.head;
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constexpr unsigned min_size = OT::ClassDefFormat1_3<SmallTypes>::min_size;
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if (vertex_len < min_size) return false;
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return vertex_len >= min_size + classValue.get_size () - classValue.len.get_size ();
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}
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};
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struct ClassDefFormat2 : public OT::ClassDefFormat2_4<SmallTypes>
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{
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bool sanitize (graph_t::vertex_t& vertex) const
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{
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int64_t vertex_len = vertex.obj.tail - vertex.obj.head;
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constexpr unsigned min_size = OT::ClassDefFormat2_4<SmallTypes>::min_size;
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if (vertex_len < min_size) return false;
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return vertex_len >= min_size + rangeRecord.get_size () - rangeRecord.len.get_size ();
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}
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};
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struct ClassDef : public OT::ClassDef
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{
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template<typename It>
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static bool add_class_def (gsubgpos_graph_context_t& c,
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unsigned parent_id,
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unsigned link_position,
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It glyph_and_class,
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unsigned max_size)
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{
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unsigned class_def_prime_id = c.graph.new_node (nullptr, nullptr);
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auto& class_def_prime_vertex = c.graph.vertices_[class_def_prime_id];
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if (!make_class_def (c, glyph_and_class, class_def_prime_id, max_size))
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return false;
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auto* class_def_link = c.graph.vertices_[parent_id].obj.real_links.push ();
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class_def_link->width = SmallTypes::size;
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class_def_link->objidx = class_def_prime_id;
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class_def_link->position = link_position;
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class_def_prime_vertex.parents.push (parent_id);
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return true;
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}
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template<typename It>
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static bool make_class_def (gsubgpos_graph_context_t& c,
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It glyph_and_class,
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unsigned dest_obj,
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unsigned max_size)
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{
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char* buffer = (char*) hb_calloc (1, max_size);
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hb_serialize_context_t serializer (buffer, max_size);
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OT::ClassDef_serialize (&serializer, glyph_and_class);
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serializer.end_serialize ();
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if (serializer.in_error ())
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{
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hb_free (buffer);
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return false;
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}
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hb_bytes_t class_def_copy = serializer.copy_bytes ();
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c.add_buffer ((char *) class_def_copy.arrayZ); // Give ownership to the context, it will cleanup the buffer.
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auto& obj = c.graph.vertices_[dest_obj].obj;
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obj.head = (char *) class_def_copy.arrayZ;
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obj.tail = obj.head + class_def_copy.length;
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hb_free (buffer);
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return true;
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}
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bool sanitize (graph_t::vertex_t& vertex) const
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{
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int64_t vertex_len = vertex.obj.tail - vertex.obj.head;
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if (vertex_len < OT::ClassDef::min_size) return false;
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switch (u.format)
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{
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case 1: return ((ClassDefFormat1*)this)->sanitize (vertex);
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case 2: return ((ClassDefFormat2*)this)->sanitize (vertex);
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#ifndef HB_NO_BEYOND_64K
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// Not currently supported
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case 3:
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case 4:
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#endif
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default: return false;
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}
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}
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};
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struct class_def_size_estimator_t
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{
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template<typename It>
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class_def_size_estimator_t (It glyph_and_class)
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: gids_consecutive (true), num_ranges_per_class (), glyphs_per_class ()
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{
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unsigned last_gid = (unsigned) -1;
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for (auto p : + glyph_and_class)
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{
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unsigned gid = p.first;
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unsigned klass = p.second;
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if (last_gid != (unsigned) -1 && gid != last_gid + 1)
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gids_consecutive = false;
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last_gid = gid;
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hb_set_t* glyphs;
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if (glyphs_per_class.has (klass, &glyphs) && glyphs) {
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glyphs->add (gid);
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continue;
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}
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hb_set_t new_glyphs;
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new_glyphs.add (gid);
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glyphs_per_class.set (klass, std::move (new_glyphs));
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}
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if (in_error ()) return;
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for (unsigned klass : glyphs_per_class.keys ())
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{
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if (!klass) continue; // class 0 doesn't get encoded.
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const hb_set_t& glyphs = glyphs_per_class.get (klass);
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hb_codepoint_t start = HB_SET_VALUE_INVALID;
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hb_codepoint_t end = HB_SET_VALUE_INVALID;
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unsigned count = 0;
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while (glyphs.next_range (&start, &end))
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count++;
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num_ranges_per_class.set (klass, count);
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}
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}
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// Incremental increase in the Coverage and ClassDef table size
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// (worst case) if all glyphs associated with 'klass' were added.
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unsigned incremental_coverage_size (unsigned klass) const
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{
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// Coverage takes 2 bytes per glyph worst case,
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return 2 * glyphs_per_class.get (klass).get_population ();
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}
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// Incremental increase in the Coverage and ClassDef table size
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// (worst case) if all glyphs associated with 'klass' were added.
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unsigned incremental_class_def_size (unsigned klass) const
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{
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// ClassDef takes 6 bytes per range
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unsigned class_def_2_size = 6 * num_ranges_per_class.get (klass);
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if (gids_consecutive)
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{
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// ClassDef1 takes 2 bytes per glyph, but only can be used
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// when gids are consecutive.
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return hb_min (2 * glyphs_per_class.get (klass).get_population (), class_def_2_size);
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}
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return class_def_2_size;
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}
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bool in_error ()
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{
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if (num_ranges_per_class.in_error ()) return true;
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if (glyphs_per_class.in_error ()) return true;
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for (const hb_set_t& s : glyphs_per_class.values ())
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{
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if (s.in_error ()) return true;
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}
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return false;
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}
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private:
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bool gids_consecutive;
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hb_hashmap_t<unsigned, unsigned> num_ranges_per_class;
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hb_hashmap_t<unsigned, hb_set_t> glyphs_per_class;
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};
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}
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#endif // GRAPH_CLASSDEF_GRAPH_HH
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