Adding upstream version 110.0.1.upstream/110.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 647 insertions, 0 deletions

diff --git a/gfx/harfbuzz/src/graph/pairpos-graph.hh b/gfx/harfbuzz/src/graph/pairpos-graph.hh
new file mode 100644
index 0000000000..1c13eb24f9
--- /dev/null
+++ b/gfx/harfbuzz/src/graph/pairpos-graph.hh
@@ -0,0 +1,647 @@
+/*
+ * 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 "split-helpers.hh"
+#include "coverage-graph.hh"
+#include "classdef-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>
+{
+  bool sanitize (graph_t::vertex_t& vertex) const
+  {
+    int64_t vertex_len = vertex.obj.tail - vertex.obj.head;
+    unsigned min_size = OT::Layout::GPOS_impl::PairPosFormat1_3<SmallTypes>::min_size;
+    if (vertex_len < min_size) return false;
+
+    return vertex_len >=
+        min_size + pairSet.get_size () - pairSet.len.get_size();
+  }
+
+  hb_vector_t<unsigned> split_subtables (gsubgpos_graph_context_t& c,
+                                         unsigned parent_index,
+                                         unsigned this_index)
+  {
+    hb_set_t visited;
+
+    const unsigned coverage_id = c.graph.index_for_offset (this_index, &coverage);
+    const unsigned coverage_size = c.graph.vertices_[coverage_id].table_size ();
+    const unsigned base_size = OT::Layout::GPOS_impl::PairPosFormat1_3<SmallTypes>::min_size;
+
+    unsigned partial_coverage_size = 4;
+    unsigned accumulated = base_size;
+    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);
+      unsigned accumulated_delta =
+          c.graph.find_subgraph_size (pair_set_index, visited) +
+          SmallTypes::size; // for PairSet offset.
+      partial_coverage_size += OT::HBUINT16::static_size;
+
+      accumulated += accumulated_delta;
+      unsigned total = accumulated + hb_min (partial_coverage_size, coverage_size);
+
+      if (total >= (1 << 16))
+      {
+        split_points.push (i);
+        accumulated = base_size + accumulated_delta;
+        partial_coverage_size = 6;
+        visited.clear (); // node sharing isn't allowed between splits.
+      }
+    }
+
+    split_context_t split_context {
+      c,
+      this,
+      c.graph.duplicate_if_shared (parent_index, this_index),
+    };
+
+    return actuate_subtable_split<split_context_t> (split_context, split_points);
+  }
+
+ private:
+
+  struct split_context_t {
+    gsubgpos_graph_context_t& c;
+    PairPosFormat1* thiz;
+    unsigned this_index;
+
+    unsigned original_count ()
+    {
+      return thiz->pairSet.len;
+    }
+
+    unsigned clone_range (unsigned start, unsigned end)
+    {
+      return thiz->clone_range (this->c, this->this_index, start, end);
+    }
+
+    bool shrink (unsigned count)
+    {
+      return thiz->shrink (this->c, this->this_index, count);
+    }
+  };
+
+  bool shrink (gsubgpos_graph_context_t& c,
+               unsigned this_index,
+               unsigned count)
+  {
+    DEBUG_MSG (SUBSET_REPACK, nullptr,
+               "  Shrinking PairPosFormat1 (%u) to [0, %u).",
+               this_index,
+               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;
+
+    auto coverage = c.graph.as_mutable_table<Coverage> (this_index, &this->coverage);
+    if (!coverage) return false;
+
+    unsigned coverage_size = coverage.vertex->table_size ();
+    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 Coverage::make_coverage (c, new_coverage, coverage.index, 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
+  {
+    DEBUG_MSG (SUBSET_REPACK, nullptr,
+               "  Cloning PairPosFormat1 (%u) range [%u, %u).", this_index, 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);
+    if (!Coverage::clone_coverage (c,
+                                   coverage_id,
+                                   pair_pos_prime_id,
+                                   2,
+                                   start, end))
+      return -1;
+
+    return pair_pos_prime_id;
+  }
+
+
+
+  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>
+{
+  bool sanitize (graph_t::vertex_t& vertex) const
+  {
+    size_t vertex_len = vertex.table_size ();
+    unsigned min_size = OT::Layout::GPOS_impl::PairPosFormat2_4<SmallTypes>::min_size;
+    if (vertex_len < min_size) return false;
+
+    const unsigned class1_count = class1Count;
+    return vertex_len >=
+        min_size + class1_count * get_class1_record_size ();
+  }
+
+  hb_vector_t<unsigned> split_subtables (gsubgpos_graph_context_t& c,
+                                         unsigned parent_index,
+                                         unsigned this_index)
+  {
+    const unsigned base_size = OT::Layout::GPOS_impl::PairPosFormat2_4<SmallTypes>::min_size;
+    const unsigned class_def_2_size = size_of (c, this_index, &classDef2);
+    const Coverage* coverage = get_coverage (c, this_index);
+    const ClassDef* class_def_1 = get_class_def_1 (c, this_index);
+    auto gid_and_class =
+        + coverage->iter ()
+        | hb_map_retains_sorting ([&] (hb_codepoint_t gid) {
+          return hb_pair_t<hb_codepoint_t, hb_codepoint_t> (gid, class_def_1->get_class (gid));
+        })
+        ;
+    class_def_size_estimator_t estimator (gid_and_class);
+
+    const unsigned class1_count = class1Count;
+    const unsigned class2_count = class2Count;
+    const unsigned class1_record_size = get_class1_record_size ();
+
+    const unsigned value_1_len = valueFormat1.get_len ();
+    const unsigned value_2_len = valueFormat2.get_len ();
+    const unsigned total_value_len = value_1_len + value_2_len;
+
+    unsigned accumulated = base_size;
+    unsigned coverage_size = 4;
+    unsigned class_def_1_size = 4;
+    unsigned max_coverage_size = coverage_size;
+    unsigned max_class_def_1_size = class_def_1_size;
+
+    hb_vector_t<unsigned> split_points;
+
+    hb_hashmap_t<unsigned, unsigned> device_tables = get_all_device_tables (c, this_index);
+    hb_vector_t<unsigned> format1_device_table_indices = valueFormat1.get_device_table_indices ();
+    hb_vector_t<unsigned> format2_device_table_indices = valueFormat2.get_device_table_indices ();
+    bool has_device_tables = bool(format1_device_table_indices) || bool(format2_device_table_indices);
+
+    hb_set_t visited;
+    for (unsigned i = 0; i < class1_count; i++)
+    {
+      unsigned accumulated_delta = class1_record_size;
+      coverage_size += estimator.incremental_coverage_size (i);
+      class_def_1_size += estimator.incremental_class_def_size (i);
+      max_coverage_size = hb_max (max_coverage_size, coverage_size);
+      max_class_def_1_size = hb_max (max_class_def_1_size, class_def_1_size);
+
+      if (has_device_tables) {
+        for (unsigned j = 0; j < class2_count; j++)
+        {
+          unsigned value1_index = total_value_len * (class2_count * i + j);
+          unsigned value2_index = value1_index + value_1_len;
+          accumulated_delta += size_of_value_record_children (c,
+                                                        device_tables,
+                                                        format1_device_table_indices,
+                                                        value1_index,
+                                                        visited);
+          accumulated_delta += size_of_value_record_children (c,
+                                                        device_tables,
+                                                        format2_device_table_indices,
+                                                        value2_index,
+                                                        visited);
+        }
+      }
+
+      accumulated += accumulated_delta;
+      unsigned total = accumulated
+                       + coverage_size + class_def_1_size + class_def_2_size
+                       // The largest object will pack last and can exceed the size limit.
+                       - hb_max (hb_max (coverage_size, class_def_1_size), class_def_2_size);
+      if (total >= (1 << 16))
+      {
+        split_points.push (i);
+        // split does not include i, so add the size for i when we reset the size counters.
+        accumulated = base_size + accumulated_delta;
+        coverage_size = 4 + estimator.incremental_coverage_size (i);
+        class_def_1_size = 4 + estimator.incremental_class_def_size (i);
+        visited.clear (); // node sharing isn't allowed between splits.
+      }
+    }
+
+    split_context_t split_context {
+      c,
+      this,
+      c.graph.duplicate_if_shared (parent_index, this_index),
+      class1_record_size,
+      total_value_len,
+      value_1_len,
+      value_2_len,
+      max_coverage_size,
+      max_class_def_1_size,
+      device_tables,
+      format1_device_table_indices,
+      format2_device_table_indices
+    };
+
+    return actuate_subtable_split<split_context_t> (split_context, split_points);
+  }
+ private:
+
+  struct split_context_t
+  {
+    gsubgpos_graph_context_t& c;
+    PairPosFormat2* thiz;
+    unsigned this_index;
+    unsigned class1_record_size;
+    unsigned value_record_len;
+    unsigned value1_record_len;
+    unsigned value2_record_len;
+    unsigned max_coverage_size;
+    unsigned max_class_def_size;
+
+    const hb_hashmap_t<unsigned, unsigned>& device_tables;
+    const hb_vector_t<unsigned>& format1_device_table_indices;
+    const hb_vector_t<unsigned>& format2_device_table_indices;
+
+    unsigned original_count ()
+    {
+      return thiz->class1Count;
+    }
+
+    unsigned clone_range (unsigned start, unsigned end)
+    {
+      return thiz->clone_range (*this, start, end);
+    }
+
+    bool shrink (unsigned count)
+    {
+      return thiz->shrink (*this, count);
+    }
+  };
+
+  size_t get_class1_record_size () const
+  {
+    const size_t class2_count = class2Count;
+    return
+        class2_count * (valueFormat1.get_size () + valueFormat2.get_size ());
+  }
+
+  unsigned clone_range (split_context_t& split_context,
+                        unsigned start, unsigned end) const
+  {
+    DEBUG_MSG (SUBSET_REPACK, nullptr,
+               "  Cloning PairPosFormat2 (%u) range [%u, %u).", split_context.this_index, start, end);
+
+    graph_t& graph = split_context.c.graph;
+
+    unsigned num_records = end - start;
+    unsigned prime_size = OT::Layout::GPOS_impl::PairPosFormat2_4<SmallTypes>::min_size
+                          + num_records * split_context.class1_record_size;
+
+    unsigned pair_pos_prime_id = split_context.c.create_node (prime_size);
+    if (pair_pos_prime_id == (unsigned) -1) return -1;
+
+    PairPosFormat2* pair_pos_prime =
+        (PairPosFormat2*) graph.object (pair_pos_prime_id).head;
+    pair_pos_prime->format = this->format;
+    pair_pos_prime->valueFormat1 = this->valueFormat1;
+    pair_pos_prime->valueFormat2 = this->valueFormat2;
+    pair_pos_prime->class1Count = num_records;
+    pair_pos_prime->class2Count = this->class2Count;
+    clone_class1_records (split_context,
+                          pair_pos_prime_id,
+                          start,
+                          end);
+
+    unsigned coverage_id =
+        graph.index_for_offset (split_context.this_index, &coverage);
+    unsigned class_def_1_id =
+        graph.index_for_offset (split_context.this_index, &classDef1);
+    auto& coverage_v = graph.vertices_[coverage_id];
+    auto& class_def_1_v = graph.vertices_[class_def_1_id];
+    Coverage* coverage_table = (Coverage*) coverage_v.obj.head;
+    ClassDef* class_def_1_table = (ClassDef*) class_def_1_v.obj.head;
+    if (!coverage_table
+        || !coverage_table->sanitize (coverage_v)
+        || !class_def_1_table
+        || !class_def_1_table->sanitize (class_def_1_v))
+      return -1;
+
+    auto klass_map =
+    + coverage_table->iter ()
+    | hb_map_retains_sorting ([&] (hb_codepoint_t gid) {
+      return hb_pair_t<hb_codepoint_t, hb_codepoint_t> (gid, class_def_1_table->get_class (gid));
+    })
+    | hb_filter ([&] (hb_codepoint_t klass) {
+      return klass >= start && klass < end;
+    }, hb_second)
+    | hb_map_retains_sorting ([&] (hb_pair_t<hb_codepoint_t, hb_codepoint_t> gid_and_class) {
+      // Classes must be from 0...N so subtract start
+      return hb_pair_t<hb_codepoint_t, hb_codepoint_t> (gid_and_class.first, gid_and_class.second - start);
+    })
+    ;
+
+    if (!Coverage::add_coverage (split_context.c,
+                                 pair_pos_prime_id,
+                                 2,
+                                 + klass_map | hb_map_retains_sorting (hb_first),
+                                 split_context.max_coverage_size))
+      return -1;
+
+    // classDef1
+    if (!ClassDef::add_class_def (split_context.c,
+                                  pair_pos_prime_id,
+                                  8,
+                                  + klass_map,
+                                  split_context.max_class_def_size))
+      return -1;
+
+    // classDef2
+    unsigned class_def_2_id =
+        graph.index_for_offset (split_context.this_index, &classDef2);
+    auto* class_def_link = graph.vertices_[pair_pos_prime_id].obj.real_links.push ();
+    class_def_link->width = SmallTypes::size;
+    class_def_link->objidx = class_def_2_id;
+    class_def_link->position = 10;
+    graph.vertices_[class_def_2_id].parents.push (pair_pos_prime_id);
+    graph.duplicate (pair_pos_prime_id, class_def_2_id);
+
+    return pair_pos_prime_id;
+  }
+
+  void clone_class1_records (split_context_t& split_context,
+                             unsigned pair_pos_prime_id,
+                             unsigned start, unsigned end) const
+  {
+    PairPosFormat2* pair_pos_prime =
+        (PairPosFormat2*) split_context.c.graph.object (pair_pos_prime_id).head;
+
+    char* start_addr = ((char*)&values[0]) + start * split_context.class1_record_size;
+    unsigned num_records = end - start;
+    hb_memcpy (&pair_pos_prime->values[0],
+            start_addr,
+            num_records * split_context.class1_record_size);
+
+    if (!split_context.format1_device_table_indices
+        && !split_context.format2_device_table_indices)
+      // No device tables to move over.
+      return;
+
+    unsigned class2_count = class2Count;
+    for (unsigned i = start; i < end; i++)
+    {
+      for (unsigned j = 0; j < class2_count; j++)
+      {
+        unsigned value1_index = split_context.value_record_len * (class2_count * i + j);
+        unsigned value2_index = value1_index + split_context.value1_record_len;
+
+        unsigned new_value1_index = split_context.value_record_len * (class2_count * (i - start) + j);
+        unsigned new_value2_index = new_value1_index + split_context.value1_record_len;
+
+        transfer_device_tables (split_context,
+                                pair_pos_prime_id,
+                                split_context.format1_device_table_indices,
+                                value1_index,
+                                new_value1_index);
+
+        transfer_device_tables (split_context,
+                                pair_pos_prime_id,
+                                split_context.format2_device_table_indices,
+                                value2_index,
+                                new_value2_index);
+      }
+    }
+  }
+
+  void transfer_device_tables (split_context_t& split_context,
+                               unsigned pair_pos_prime_id,
+                               const hb_vector_t<unsigned>& device_table_indices,
+                               unsigned old_value_record_index,
+                               unsigned new_value_record_index) const
+  {
+    PairPosFormat2* pair_pos_prime =
+        (PairPosFormat2*) split_context.c.graph.object (pair_pos_prime_id).head;
+
+    for (unsigned i : device_table_indices)
+    {
+      OT::Offset16* record = (OT::Offset16*) &values[old_value_record_index + i];
+      unsigned record_position = ((char*) record) - ((char*) this);
+      if (!split_context.device_tables.has (record_position)) continue;
+
+      split_context.c.graph.move_child (
+          split_context.this_index,
+          record,
+          pair_pos_prime_id,
+          (OT::Offset16*) &pair_pos_prime->values[new_value_record_index + i]);
+    }
+  }
+
+  bool shrink (split_context_t& split_context,
+               unsigned count)
+  {
+    DEBUG_MSG (SUBSET_REPACK, nullptr,
+               "  Shrinking PairPosFormat2 (%u) to [0, %u).",
+               split_context.this_index,
+               count);
+    unsigned old_count = class1Count;
+    if (count >= old_count)
+      return true;
+
+    graph_t& graph = split_context.c.graph;
+    class1Count = count;
+    graph.vertices_[split_context.this_index].obj.tail -=
+        (old_count - count) * split_context.class1_record_size;
+
+    auto coverage =
+        graph.as_mutable_table<Coverage> (split_context.this_index, &this->coverage);
+    if (!coverage) return false;
+
+    auto class_def_1 =
+        graph.as_mutable_table<ClassDef> (split_context.this_index, &classDef1);
+    if (!class_def_1) return false;
+
+    auto klass_map =
+    + coverage.table->iter ()
+    | hb_map_retains_sorting ([&] (hb_codepoint_t gid) {
+      return hb_pair_t<hb_codepoint_t, hb_codepoint_t> (gid, class_def_1.table->get_class (gid));
+    })
+    | hb_filter ([&] (hb_codepoint_t klass) {
+      return klass < count;
+    }, hb_second)
+    ;
+
+    auto new_coverage = + klass_map | hb_map_retains_sorting (hb_first);
+    if (!Coverage::make_coverage (split_context.c,
+                                  + new_coverage,
+                                  coverage.index,
+                                  // existing ranges my not be kept, worst case size is a format 1
+                                  // coverage table.
+                                  4 + new_coverage.len() * 2))
+      return false;
+
+    return ClassDef::make_class_def (split_context.c,
+                                     + klass_map,
+                                     class_def_1.index,
+                                     class_def_1.vertex->table_size ());
+  }
+
+  hb_hashmap_t<unsigned, unsigned>
+  get_all_device_tables (gsubgpos_graph_context_t& c,
+                         unsigned this_index) const
+  {
+    const auto& v = c.graph.vertices_[this_index];
+    return v.position_to_index_map ();
+  }
+
+  const Coverage* get_coverage (gsubgpos_graph_context_t& c,
+                          unsigned this_index) const
+  {
+    unsigned coverage_id = c.graph.index_for_offset (this_index, &coverage);
+    auto& coverage_v = c.graph.vertices_[coverage_id];
+
+    Coverage* coverage_table = (Coverage*) coverage_v.obj.head;
+    if (!coverage_table || !coverage_table->sanitize (coverage_v))
+      return &Null(Coverage);
+    return coverage_table;
+  }
+
+  const ClassDef* get_class_def_1 (gsubgpos_graph_context_t& c,
+                                   unsigned this_index) const
+  {
+    unsigned class_def_1_id = c.graph.index_for_offset (this_index, &classDef1);
+    auto& class_def_1_v = c.graph.vertices_[class_def_1_id];
+
+    ClassDef* class_def_1_table = (ClassDef*) class_def_1_v.obj.head;
+    if (!class_def_1_table || !class_def_1_table->sanitize (class_def_1_v))
+      return &Null(ClassDef);
+    return class_def_1_table;
+  }
+
+  unsigned size_of_value_record_children (gsubgpos_graph_context_t& c,
+                                          const hb_hashmap_t<unsigned, unsigned>& device_tables,
+                                          const hb_vector_t<unsigned> device_table_indices,
+                                          unsigned value_record_index,
+                                          hb_set_t& visited)
+  {
+    unsigned size = 0;
+    for (unsigned i : device_table_indices)
+    {
+      OT::Layout::GPOS_impl::Value* record = &values[value_record_index + i];
+      unsigned record_position = ((char*) record) - ((char*) this);
+      unsigned* obj_idx;
+      if (!device_tables.has (record_position, &obj_idx)) continue;
+      size += c.graph.find_subgraph_size (*obj_idx, visited);
+    }
+    return size;
+  }
+
+  unsigned size_of (gsubgpos_graph_context_t& c,
+                    unsigned this_index,
+                    const void* offset) const
+  {
+    const unsigned id = c.graph.index_for_offset (this_index, offset);
+    return c.graph.vertices_[id].table_size ();
+  }
+};
+
+struct PairPos : public OT::Layout::GPOS_impl::PairPos
+{
+  hb_vector_t<unsigned> split_subtables (gsubgpos_graph_context_t& c,
+                                         unsigned parent_index,
+                                         unsigned this_index)
+  {
+    switch (u.format) {
+    case 1:
+      return ((PairPosFormat1*)(&u.format1))->split_subtables (c, parent_index, this_index);
+    case 2:
+      return ((PairPosFormat2*)(&u.format2))->split_subtables (c, parent_index, this_index);
+#ifndef HB_NO_BEYOND_64K
+    case 3: HB_FALLTHROUGH;
+    case 4: HB_FALLTHROUGH;
+      // Don't split 24bit PairPos's.
+#endif
+    default:
+      return hb_vector_t<unsigned> ();
+    }
+  }
+
+  bool sanitize (graph_t::vertex_t& vertex) const
+  {
+    int64_t vertex_len = vertex.obj.tail - vertex.obj.head;
+    if (vertex_len < u.format.get_size ()) return false;
+
+    switch (u.format) {
+    case 1:
+      return ((PairPosFormat1*)(&u.format1))->sanitize (vertex);
+    case 2:
+      return ((PairPosFormat2*)(&u.format2))->sanitize (vertex);
+#ifndef HB_NO_BEYOND_64K
+    case 3: HB_FALLTHROUGH;
+    case 4: HB_FALLTHROUGH;
+#endif
+    default:
+      // We don't handle format 3 and 4 here.
+      return false;
+    }
+  }
+};
+
+}
+
+#endif  // GRAPH_PAIRPOS_GRAPH_HH