[repacker] pull out PairPosFormat1,2::do_split() into a common helper method.

src/Makefile.sources

@@ -355,6 +355,7 @@ HB_SUBSET_sources = \
 	graph/coverage-graph.hh \
 	graph/classdef-graph.hh \
 	graph/pairpos-graph.hh \
+	graph/split-helpers.hh \
 	graph/serialize.hh \
 	$(NULL)
 

src/graph/pairpos-graph.hh

@@ -27,6 +27,7 @@
 #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"
@@ -75,45 +76,37 @@ struct PairPosFormat1 : public OT::Layout::GPOS_impl::PairPosFormat1_3<SmallType
       }
     }
 
-    return do_split (c, this_index, split_points);
+    split_context_t split_context {
+      c,
+      this,
+      this_index,
+    };
+
+    return actuate_subtable_split<split_context_t> (split_context, split_points);
   }
 
  private:
 
-  // Split this PairPos into two or more PairPos's. split_points defines
+  struct split_context_t {
-  // the indices (first index to include in the new table) to split at.
+    gsubgpos_graph_context_t& c;
-  // Returns the object id's of the newly created PairPos subtables.
+    PairPosFormat1* thiz;
-  hb_vector_t<unsigned> do_split (gsubgpos_graph_context_t& c,
+    unsigned this_index;
-                                  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 original_count ()
     {
-      unsigned start = split_points[i];
+      return thiz->pairSet.len;
-      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]))
+    unsigned clone_range (unsigned start, unsigned end)
     {
-      new_objects.reset ();
+      return thiz->clone_range (this->c, this->this_index, start, end);
-      new_objects.allocated = -1; // mark error
     }
 
-    return new_objects;
+    bool shrink (unsigned count)
-  }
+    {
+      return thiz->shrink (this->c, this->this_index, count);
+    }
+  };
 
   bool shrink (gsubgpos_graph_context_t& c,
                unsigned this_index,
@@ -267,8 +260,9 @@ struct PairPosFormat2 : public OT::Layout::GPOS_impl::PairPosFormat2_4<SmallType
       }
     }
 
-    split_context split_context {
+    split_context_t split_context {
       c,
+      this,
       this_index,
       class1_record_size,
       total_value_len,
@@ -279,13 +273,14 @@ struct PairPosFormat2 : public OT::Layout::GPOS_impl::PairPosFormat2_4<SmallType
       format2_device_table_indices
     };
 
-    return do_split (split_context, split_points);
+    return actuate_subtable_split<split_context_t> (split_context, split_points);
   }
  private:
 
-  struct split_context
+  struct split_context_t
   {
     gsubgpos_graph_context_t& c;
+    PairPosFormat2* thiz;
     unsigned this_index;
     unsigned class1_record_size;
     unsigned value_record_len;
@@ -295,6 +290,21 @@ struct PairPosFormat2 : public OT::Layout::GPOS_impl::PairPosFormat2_4<SmallType
     const hb_hashmap_t<void*, 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
@@ -304,40 +314,7 @@ struct PairPosFormat2 : public OT::Layout::GPOS_impl::PairPosFormat2_4<SmallType
         class2_count * (valueFormat1.get_size () + valueFormat2.get_size ());
   }
 
-  hb_vector_t<unsigned> do_split (split_context& split_context,
+  unsigned clone_range (split_context_t& split_context,
-                                  const hb_vector_t<unsigned>& split_points)
-  {
-    // TODO(garretrieger): refactor into a common method shared between subtables.
-    //                     template on context which could provide the clone and shrink methods.
-    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] : class1Count;
-      unsigned id = clone_range (split_context, start, end);
-
-      if (id == (unsigned) -1)
-      {
-        new_objects.reset ();
-        new_objects.allocated = -1; // mark error
-        return new_objects;
-      }
-      new_objects.push (id);
-    }
-
-    if (!shrink (split_context, split_points[0]))
-    {
-      new_objects.reset ();
-      new_objects.allocated = -1; // mark error
-    }
-
-    return new_objects;
-  }
-
-  unsigned clone_range (split_context& split_context,
                         unsigned start, unsigned end) const
   {
     DEBUG_MSG (SUBSET_REPACK, nullptr,
@@ -396,7 +373,7 @@ struct PairPosFormat2 : public OT::Layout::GPOS_impl::PairPosFormat2_4<SmallType
     return pair_pos_prime_id;
   }
 
-  void clone_class1_records (split_context& split_context,
+  void clone_class1_records (split_context_t& split_context,
                              unsigned pair_pos_prime_id,
                              unsigned start, unsigned end) const
   {
@@ -440,7 +417,7 @@ struct PairPosFormat2 : public OT::Layout::GPOS_impl::PairPosFormat2_4<SmallType
     }
   }
 
-  void transfer_device_tables (split_context& split_context,
+  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,
@@ -462,7 +439,7 @@ struct PairPosFormat2 : public OT::Layout::GPOS_impl::PairPosFormat2_4<SmallType
     }
   }
 
-  bool shrink (split_context& split_context,
+  bool shrink (split_context_t& split_context,
                unsigned count)
   {
     DEBUG_MSG (SUBSET_REPACK, nullptr,

src/graph/split-helpers.hh

@@ -0,0 +1,68 @@
+/*
+ * 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_SPLIT_HELPERS_HH
+#define GRAPH_SPLIT_HELPERS_HH
+
+namespace graph {
+
+template<typename Context>
+hb_vector_t<unsigned> actuate_subtable_split (Context& split_context,
+                                              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]
+                   : split_context.original_count ();
+    unsigned id = split_context.clone_range (start, end);
+
+    if (id == (unsigned) -1)
+    {
+      new_objects.reset ();
+      new_objects.allocated = -1; // mark error
+      return new_objects;
+    }
+    new_objects.push (id);
+  }
+
+  if (!split_context.shrink (split_points[0]))
+  {
+    new_objects.reset ();
+    new_objects.allocated = -1; // mark error
+  }
+
+  return new_objects;
+}
+
+}
+
+#endif  // GRAPH_SPLIT_HELPERS_HH

src/meson.build

@@ -351,6 +351,7 @@ hb_subset_sources = files(
   'graph/pairpos-graph.hh',
   'graph/coverage-graph.hh',
   'graph/classdef-graph.hh',
+  'graph/split-helpers.hh',
   'hb-subset.cc',
   'hb-subset.hh',
 )