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/*
* 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;
hb_barrier ();
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;
hb_barrier ();
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.add_parent (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;
hb_barrier ();
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
{
// TODO(garretrieger): update to support beyond64k coverage/classdef tables.
constexpr static unsigned class_def_format1_base_size = 6;
constexpr static unsigned class_def_format2_base_size = 4;
constexpr static unsigned coverage_base_size = 4;
constexpr static unsigned bytes_per_range = 6;
constexpr static unsigned bytes_per_glyph = 2;
template<typename It>
class_def_size_estimator_t (It glyph_and_class)
: num_ranges_per_class (), glyphs_per_class ()
{
reset();
for (auto p : + glyph_and_class)
{
unsigned gid = p.first;
unsigned klass = p.second;
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);
}
}
void reset() {
class_def_1_size = class_def_format1_base_size;
class_def_2_size = class_def_format2_base_size;
included_glyphs.clear();
included_classes.clear();
}
// Compute the size of coverage for all glyphs added via 'add_class_def_size'.
unsigned coverage_size () const
{
unsigned format1_size = coverage_base_size + bytes_per_glyph * included_glyphs.get_population();
unsigned format2_size = coverage_base_size + bytes_per_range * num_glyph_ranges();
return hb_min(format1_size, format2_size);
}
// Compute the new size of the ClassDef table if all glyphs associated with 'klass' were added.
unsigned add_class_def_size (unsigned klass)
{
if (!included_classes.has(klass)) {
hb_set_t* glyphs = nullptr;
if (glyphs_per_class.has(klass, &glyphs)) {
included_glyphs.union_(*glyphs);
}
class_def_1_size = class_def_format1_base_size;
if (!included_glyphs.is_empty()) {
unsigned min_glyph = included_glyphs.get_min();
unsigned max_glyph = included_glyphs.get_max();
class_def_1_size += bytes_per_glyph * (max_glyph - min_glyph + 1);
}
class_def_2_size += bytes_per_range * num_ranges_per_class.get (klass);
included_classes.add(klass);
}
return hb_min (class_def_1_size, class_def_2_size);
}
unsigned num_glyph_ranges() const {
hb_codepoint_t start = HB_SET_VALUE_INVALID;
hb_codepoint_t end = HB_SET_VALUE_INVALID;
unsigned count = 0;
while (included_glyphs.next_range (&start, &end)) {
count++;
}
return count;
}
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:
hb_hashmap_t<unsigned, unsigned> num_ranges_per_class;
hb_hashmap_t<unsigned, hb_set_t> glyphs_per_class;
hb_set_t included_classes;
hb_set_t included_glyphs;
unsigned class_def_1_size;
unsigned class_def_2_size;
};
}
#endif // GRAPH_CLASSDEF_GRAPH_HH