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harfbuzz/src/graph/pairpos-graph.hh

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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
*/
#ifndef GRAPH_PAIRPOS_GRAPH_HH
#define GRAPH_PAIRPOS_GRAPH_HH
#include "../OT/Layout/GPOS/PairPos.hh"
#include "../OT/Layout/GPOS/PosLookupSubTable.hh"
namespace graph {
struct PairPosFormat1 : public OT::Layout::GPOS_impl::PairPosFormat1_3<SmallTypes>
{
hb_vector_t<unsigned> split_subtables (gsubgpos_graph_context_t& c, unsigned this_index)
{
printf("Checking if pair pos %u needs splits...\n", this_index);
hb_set_t visited;
const unsigned base_size = OT::Layout::GPOS_impl::PairPosFormat1_3<SmallTypes>::min_size;
printf(" base_size = %u\n", base_size);
unsigned accumulated = base_size;
// TODO: include coverage size
unsigned num_pair_sets = pairSet.len;
printf(" num_pair_sets = %u\n", num_pair_sets);
hb_vector_t<unsigned> split_points;
for (unsigned i = 0; i < pairSet.len; i++)
{
unsigned pair_set_index = pair_set_graph_index (c, this_index, i);
accumulated += c.graph.find_subgraph_size (pair_set_index, visited);
accumulated += SmallTypes::size; // for PairSet offset.
if (accumulated > (1 << 13)) // TODO (1 << 16)
{
printf(" PairPos split needed %u/%u\n", i, num_pair_sets);
split_points.push (i);
accumulated = base_size;
}
}
return do_split (c, this_index, split_points);
}
private:
// Split this PairPos into two or more PairPos's. split_points defines
// the indices (first index to include in the new table) to split at.
// Returns the object id's of the newly created PairPos subtables.
hb_vector_t<unsigned> do_split (gsubgpos_graph_context_t& c,
unsigned this_index,
const hb_vector_t<unsigned> split_points)
{
hb_vector_t<unsigned> new_objects;
if (!split_points)
return new_objects;
for (unsigned i = 0; i < split_points.length; i++)
{
unsigned start = split_points[i];
unsigned end = (i < split_points.length - 1) ? split_points[i + 1] : pairSet.len;
unsigned id = clone_range (c, this_index, start, end);
if (id == (unsigned) -1)
{
new_objects.reset ();
new_objects.allocated = -1; // mark error
return new_objects;
}
new_objects.push (id);
}
if (!shrink (c, this_index, split_points[0]))
{
new_objects.reset ();
new_objects.allocated = -1; // mark error
}
return new_objects;
}
bool shrink (gsubgpos_graph_context_t& c,
unsigned this_index,
unsigned count)
{
printf(" shrink to [0, %u).\n", count);
unsigned old_count = pairSet.len;
if (count >= old_count)
return true;
pairSet.len = count;
c.graph.vertices_[this_index].obj.tail -= (old_count - count) * SmallTypes::size;
unsigned coverage_id = c.graph.index_for_offset (this_index, &coverage);
unsigned coverage_size = c.graph.vertices_[coverage_id].table_size ();
OT::Layout::Common::Coverage* coverage_table =
(OT::Layout::Common::Coverage*) c.graph.object (coverage_id).head;
auto new_coverage =
+ hb_zip (coverage_table->iter (), hb_range ())
| hb_filter ([&] (hb_pair_t<unsigned, unsigned> p) {
return p.second < count;
})
| hb_map_retains_sorting (hb_first)
;
return make_coverage (c, new_coverage, coverage_id, coverage_size);
}
// Create a new PairPos including PairSet's from start (inclusive) to end (exclusive).
// Returns object id of the new object.
unsigned clone_range (gsubgpos_graph_context_t& c,
unsigned this_index,
unsigned start, unsigned end) const
{
printf(" cloning range [%u, %u).\n", start, end);
unsigned num_pair_sets = end - start;
unsigned prime_size = OT::Layout::GPOS_impl::PairPosFormat1_3<SmallTypes>::min_size
+ num_pair_sets * SmallTypes::size;
unsigned pair_pos_prime_id = c.create_node (prime_size);
if (pair_pos_prime_id == (unsigned) -1) return -1;
PairPosFormat1* pair_pos_prime = (PairPosFormat1*) c.graph.object (pair_pos_prime_id).head;
pair_pos_prime->format = this->format;
pair_pos_prime->valueFormat[0] = this->valueFormat[0];
pair_pos_prime->valueFormat[1] = this->valueFormat[1];
pair_pos_prime->pairSet.len = num_pair_sets;
for (unsigned i = start; i < end; i++)
{
c.graph.move_child<> (this_index,
&pairSet[i],
pair_pos_prime_id,
&pair_pos_prime->pairSet[i - start]);
}
unsigned coverage_id = c.graph.index_for_offset (this_index, &coverage);
unsigned coverage_size = c.graph.vertices_[coverage_id].table_size ();
OT::Layout::Common::Coverage* coverage_table =
(OT::Layout::Common::Coverage*) c.graph.object (coverage_id).head;
auto new_coverage =
+ hb_zip (coverage_table->iter (), hb_range ())
| hb_filter ([&] (hb_pair_t<unsigned, unsigned> p) {
return p.second >= start && p.second < end;
})
| hb_map_retains_sorting (hb_first)
;
unsigned coverage_prime_id = c.graph.new_node (nullptr, nullptr);
auto& coverage_prime_vertex = c.graph.vertices_[coverage_prime_id];
if (!make_coverage (c, new_coverage, coverage_prime_id, coverage_size))
return -1;
auto* coverage_link = c.graph.vertices_[pair_pos_prime_id].obj.real_links.push ();
coverage_link->width = SmallTypes::size;
coverage_link->objidx = coverage_prime_id;
coverage_link->position = 2;
coverage_prime_vertex.parents.push (pair_pos_prime_id);
return pair_pos_prime_id;
}
template<typename It>
bool make_coverage (gsubgpos_graph_context_t& c,
It glyphs,
unsigned dest_obj,
unsigned max_size) const
{
char* buffer = (char*) hb_calloc (1, max_size);
hb_serialize_context_t serializer = hb_serialize_context_t (buffer,
max_size);
Coverage_serialize (&serializer, glyphs);
serializer.end_serialize ();
if (serializer.in_error ())
{
hb_free (buffer);
return false;
}
hb_bytes_t coverage_copy = serializer.copy_bytes ();
c.add_buffer ((char *) coverage_copy.arrayZ); // Give ownership to the context, it will cleanup the buffer.
auto& obj = c.graph.vertices_[dest_obj].obj;
obj.head = (char *) coverage_copy.arrayZ;
obj.tail = obj.head + coverage_copy.length;
hb_free (buffer);
return true;
}
unsigned pair_set_graph_index (gsubgpos_graph_context_t& c, unsigned this_index, unsigned i) const
{
return c.graph.index_for_offset (this_index, &pairSet[i]);
}
};
struct PairPosFormat2 : public OT::Layout::GPOS_impl::PairPosFormat2_4<SmallTypes>
{
hb_vector_t<unsigned> split_subtables (gsubgpos_graph_context_t& c, unsigned this_index)
{
// TODO
return hb_vector_t<unsigned> ();
}
};
struct PairPos : public OT::Layout::GPOS_impl::PairPos
{
hb_vector_t<unsigned> split_subtables (gsubgpos_graph_context_t& c, unsigned this_index)
{
unsigned format = u.format;
printf("PairPos::format = %u\n", format);
switch (u.format) {
case 1:
return ((PairPosFormat1*)(&u.format1))->split_subtables (c, this_index);
case 2:
return ((PairPosFormat2*)(&u.format2))->split_subtables (c, this_index);
#ifndef HB_NO_BORING_EXPANSION
case 3:
case 4:
// Don't split 24bit PairPos's.
#endif
default:
return hb_vector_t<unsigned> ();
}
}
};
}
#endif // GRAPH_PAIRPOS_GRAPH_HH
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