diff options
Diffstat (limited to 'gfx/harfbuzz/src/graph/classdef-graph.hh')
| -rw-r--r-- | gfx/harfbuzz/src/graph/classdef-graph.hh | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/gfx/harfbuzz/src/graph/classdef-graph.hh b/gfx/harfbuzz/src/graph/classdef-graph.hh new file mode 100644 index 0000000000..c2e24a7067 --- /dev/null +++ b/gfx/harfbuzz/src/graph/classdef-graph.hh @@ -0,0 +1,216 @@ +/* + * 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 |