harfbuzz/src/graph/gsubgpos-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
*/
#include "graph.hh"
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#include "../hb-ot-layout-gsubgpos.hh"
#include "../OT/Layout/GSUB/ExtensionSubst.hh"
#include "gsubgpos-context.hh"
#include "pairpos-graph.hh"
#include "markbasepos-graph.hh"
#ifndef GRAPH_GSUBGPOS_GRAPH_HH
#define GRAPH_GSUBGPOS_GRAPH_HH
namespace graph {
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struct Lookup;
template<typename T>
struct ExtensionFormat1 : public OT::ExtensionFormat1<T>
{
void reset(unsigned type)
{
this->format = 1;
this->extensionLookupType = type;
this->extensionOffset = 0;
}
bool sanitize (graph_t::vertex_t& vertex) const
{
int64_t vertex_len = vertex.obj.tail - vertex.obj.head;
return vertex_len >= OT::ExtensionFormat1<T>::static_size;
}
unsigned get_lookup_type () const
{
return this->extensionLookupType;
}
unsigned get_subtable_index (graph_t& graph, unsigned this_index) const
{
return graph.index_for_offset (this_index, &this->extensionOffset);
}
};
struct Lookup : public OT::Lookup
{
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unsigned number_of_subtables () const
{
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return subTable.len;
}
bool sanitize (graph_t::vertex_t& vertex) const
{
int64_t vertex_len = vertex.obj.tail - vertex.obj.head;
if (vertex_len < OT::Lookup::min_size) return false;
return vertex_len >= this->get_size ();
}
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bool is_extension (hb_tag_t table_tag) const
{
return lookupType == extension_type (table_tag);
}
bool make_extension (gsubgpos_graph_context_t& c,
unsigned this_index)
{
unsigned type = lookupType;
unsigned ext_type = extension_type (c.table_tag);
if (!ext_type || is_extension (c.table_tag))
{
// NOOP
return true;
}
DEBUG_MSG (SUBSET_REPACK, nullptr,
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"Promoting lookup type %u (obj %u) to extension.",
type,
this_index);
for (unsigned i = 0; i < subTable.len; i++)
{
unsigned subtable_index = c.graph.index_for_offset (this_index, &subTable[i]);
if (!make_subtable_extension (c,
this_index,
subtable_index))
return false;
}
lookupType = ext_type;
return true;
}
bool split_subtables_if_needed (gsubgpos_graph_context_t& c,
unsigned this_index)
{
unsigned type = lookupType;
bool is_ext = is_extension (c.table_tag);
if (c.table_tag != HB_OT_TAG_GPOS)
return true;
if (!is_ext &&
type != OT::Layout::GPOS_impl::PosLookupSubTable::Type::Pair &&
type != OT::Layout::GPOS_impl::PosLookupSubTable::Type::MarkBase)
return true;
hb_vector_t<hb_pair_t<unsigned, hb_vector_t<unsigned>>> all_new_subtables;
for (unsigned i = 0; i < subTable.len; i++)
{
unsigned subtable_index = c.graph.index_for_offset (this_index, &subTable[i]);
unsigned parent_index = this_index;
if (is_ext) {
unsigned ext_subtable_index = subtable_index;
parent_index = ext_subtable_index;
ExtensionFormat1<OT::Layout::GSUB_impl::ExtensionSubst>* extension =
(ExtensionFormat1<OT::Layout::GSUB_impl::ExtensionSubst>*)
c.graph.object (ext_subtable_index).head;
if (!extension || !extension->sanitize (c.graph.vertices_[ext_subtable_index]))
continue;
subtable_index = extension->get_subtable_index (c.graph, ext_subtable_index);
type = extension->get_lookup_type ();
if (type != OT::Layout::GPOS_impl::PosLookupSubTable::Type::Pair
&& type != OT::Layout::GPOS_impl::PosLookupSubTable::Type::MarkBase)
continue;
}
hb_vector_t<unsigned> new_sub_tables;
switch (type)
{
case 2:
new_sub_tables = split_subtable<PairPos> (c, parent_index, subtable_index); break;
case 4:
new_sub_tables = split_subtable<MarkBasePos> (c, parent_index, subtable_index); break;
default:
break;
}
if (new_sub_tables.in_error ()) return false;
if (!new_sub_tables) continue;
hb_pair_t<unsigned, hb_vector_t<unsigned>>* entry = all_new_subtables.push ();
entry->first = i;
entry->second = std::move (new_sub_tables);
}
if (all_new_subtables) {
add_sub_tables (c, this_index, type, all_new_subtables);
}
return true;
}
template<typename T>
hb_vector_t<unsigned> split_subtable (gsubgpos_graph_context_t& c,
unsigned parent_idx,
unsigned objidx)
{
T* sub_table = (T*) c.graph.object (objidx).head;
if (!sub_table || !sub_table->sanitize (c.graph.vertices_[objidx]))
return hb_vector_t<unsigned> ();
return sub_table->split_subtables (c, parent_idx, objidx);
}
void add_sub_tables (gsubgpos_graph_context_t& c,
unsigned this_index,
unsigned type,
hb_vector_t<hb_pair_t<unsigned, hb_vector_t<unsigned>>>& subtable_ids)
{
bool is_ext = is_extension (c.table_tag);
auto& v = c.graph.vertices_[this_index];
fix_existing_subtable_links (c, this_index, subtable_ids);
unsigned new_subtable_count = 0;
for (const auto& p : subtable_ids)
new_subtable_count += p.second.length;
size_t new_size = v.table_size ()
+ new_subtable_count * OT::Offset16::static_size;
char* buffer = (char*) hb_calloc (1, new_size);
c.add_buffer (buffer);
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hb_memcpy (buffer, v.obj.head, v.table_size());
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v.obj.head = buffer;
v.obj.tail = buffer + new_size;
Lookup* new_lookup = (Lookup*) buffer;
unsigned shift = 0;
new_lookup->subTable.len = subTable.len + new_subtable_count;
for (const auto& p : subtable_ids)
{
unsigned offset_index = p.first + shift + 1;
shift += p.second.length;
for (unsigned subtable_id : p.second)
{
if (is_ext)
{
unsigned ext_id = create_extension_subtable (c, subtable_id, type);
c.graph.vertices_[subtable_id].parents.push (ext_id);
subtable_id = ext_id;
}
auto* link = v.obj.real_links.push ();
link->width = 2;
link->objidx = subtable_id;
link->position = (char*) &new_lookup->subTable[offset_index++] -
(char*) new_lookup;
c.graph.vertices_[subtable_id].parents.push (this_index);
}
}
// Repacker sort order depends on link order, which we've messed up so resort it.
v.obj.real_links.qsort ();
// The head location of the lookup has changed, invalidating the lookups map entry
// in the context. Update the map.
c.lookups.set (this_index, new_lookup);
}
void fix_existing_subtable_links (gsubgpos_graph_context_t& c,
unsigned this_index,
hb_vector_t<hb_pair_t<unsigned, hb_vector_t<unsigned>>>& subtable_ids)
{
auto& v = c.graph.vertices_[this_index];
Lookup* lookup = (Lookup*) v.obj.head;
unsigned shift = 0;
for (const auto& p : subtable_ids)
{
unsigned insert_index = p.first + shift;
unsigned pos_offset = p.second.length * OT::Offset16::static_size;
unsigned insert_offset = (char*) &lookup->subTable[insert_index] - (char*) lookup;
shift += p.second.length;
for (auto& l : v.obj.all_links_writer ())
{
if (l.position > insert_offset) l.position += pos_offset;
}
}
}
unsigned create_extension_subtable (gsubgpos_graph_context_t& c,
unsigned subtable_index,
unsigned type)
{
unsigned extension_size = OT::ExtensionFormat1<OT::Layout::GSUB_impl::ExtensionSubst>::static_size;
unsigned ext_index = c.create_node (extension_size);
if (ext_index == (unsigned) -1)
return -1;
auto& ext_vertex = c.graph.vertices_[ext_index];
ExtensionFormat1<OT::Layout::GSUB_impl::ExtensionSubst>* extension =
(ExtensionFormat1<OT::Layout::GSUB_impl::ExtensionSubst>*) ext_vertex.obj.head;
extension->reset (type);
// Make extension point at the subtable.
auto* l = ext_vertex.obj.real_links.push ();
l->width = 4;
l->objidx = subtable_index;
l->position = 4;
return ext_index;
}
bool make_subtable_extension (gsubgpos_graph_context_t& c,
unsigned lookup_index,
unsigned subtable_index)
{
unsigned type = lookupType;
unsigned ext_index = create_extension_subtable(c, subtable_index, type);
if (ext_index == (unsigned) -1)
return false;
auto& lookup_vertex = c.graph.vertices_[lookup_index];
for (auto& l : lookup_vertex.obj.real_links.writer ())
{
if (l.objidx == subtable_index)
// Change lookup to point at the extension.
l.objidx = ext_index;
}
// Make extension point at the subtable.
auto& ext_vertex = c.graph.vertices_[ext_index];
auto& subtable_vertex = c.graph.vertices_[subtable_index];
ext_vertex.parents.push (lookup_index);
subtable_vertex.remap_parent (lookup_index, ext_index);
return true;
}
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private:
unsigned extension_type (hb_tag_t table_tag) const
{
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switch (table_tag)
{
case HB_OT_TAG_GPOS: return 9;
case HB_OT_TAG_GSUB: return 7;
default: return 0;
}
}
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};
template <typename T>
struct LookupList : public OT::LookupList<T>
{
bool sanitize (const graph_t::vertex_t& vertex) const
{
int64_t vertex_len = vertex.obj.tail - vertex.obj.head;
if (vertex_len < OT::LookupList<T>::min_size) return false;
return vertex_len >= OT::LookupList<T>::item_size * this->len;
}
};
struct GSTAR : public OT::GSUBGPOS
{
static GSTAR* graph_to_gstar (graph_t& graph)
{
const auto& r = graph.root ();
GSTAR* gstar = (GSTAR*) r.obj.head;
if (!gstar || !gstar->sanitize (r))
return nullptr;
return gstar;
}
const void* get_lookup_list_field_offset () const
{
switch (u.version.major) {
case 1: return u.version1.get_lookup_list_offset ();
#ifndef HB_NO_BEYOND_64K
case 2: return u.version2.get_lookup_list_offset ();
#endif
default: return 0;
}
}
bool sanitize (const graph_t::vertex_t& vertex)
{
int64_t len = vertex.obj.tail - vertex.obj.head;
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if (len < OT::GSUBGPOS::min_size) return false;
return len >= get_size ();
}
void find_lookups (graph_t& graph,
hb_hashmap_t<unsigned, Lookup*>& lookups /* OUT */)
{
switch (u.version.major) {
case 1: find_lookups<SmallTypes> (graph, lookups); break;
#ifndef HB_NO_BEYOND_64K
case 2: find_lookups<MediumTypes> (graph, lookups); break;
#endif
}
}
unsigned get_lookup_list_index (graph_t& graph)
{
return graph.index_for_offset (graph.root_idx (),
get_lookup_list_field_offset());
}
template<typename Types>
void find_lookups (graph_t& graph,
hb_hashmap_t<unsigned, Lookup*>& lookups /* OUT */)
{
unsigned lookup_list_idx = get_lookup_list_index (graph);
const LookupList<Types>* lookupList =
(const LookupList<Types>*) graph.object (lookup_list_idx).head;
if (!lookupList || !lookupList->sanitize (graph.vertices_[lookup_list_idx]))
return;
for (unsigned i = 0; i < lookupList->len; i++)
{
unsigned lookup_idx = graph.index_for_offset (lookup_list_idx, &(lookupList->arrayZ[i]));
Lookup* lookup = (Lookup*) graph.object (lookup_idx).head;
if (!lookup || !lookup->sanitize (graph.vertices_[lookup_idx])) continue;
lookups.set (lookup_idx, lookup);
}
}
};
}
#endif /* GRAPH_GSUBGPOS_GRAPH_HH */