From 68ac767e430c4dfe4c556b2c4f962cc3dfc5d3e4 Mon Sep 17 00:00:00 2001
From: blueshade7 <ariza@typekit.com>
Date: Fri, 12 Jul 2019 23:02:29 -0700
Subject: [PATCH] added skip(), get_next_value() to inc_bimap to subset
 VarStore with retain-gids

---
 src/hb-bimap.hh            | 25 ++++++++++++++++++++++++-
 src/hb-ot-layout-common.hh | 14 +++++++-------
 2 files changed, 31 insertions(+), 8 deletions(-)

diff --git a/src/hb-bimap.hh b/src/hb-bimap.hh
index a773951ab..cae0a4dea 100644
--- a/src/hb-bimap.hh
+++ b/src/hb-bimap.hh
@@ -94,6 +94,14 @@ struct hb_bimap_t
 /* Inremental bimap: only lhs is given, rhs is incrementally assigned */
 struct hb_inc_bimap_t : hb_bimap_t
 {
+  hb_inc_bimap_t () { init (); }
+
+  void init ()
+  {
+    hb_bimap_t::init ();
+    next_value = 0;
+  }
+
   /* Add a mapping from lhs to rhs with a unique value if lhs is unknown.
    * Return the rhs value as the result.
    */
@@ -102,12 +110,24 @@ struct hb_inc_bimap_t : hb_bimap_t
     hb_codepoint_t  rhs = forw_map[lhs];
     if (rhs == HB_MAP_VALUE_INVALID)
     {
-      rhs = get_population ();
+      rhs = next_value++;
       set (lhs, rhs);
     }
     return rhs;
   }
 
+  hb_codepoint_t skip ()
+  { return next_value++; }
+
+  hb_codepoint_t get_next_value () const
+  { return next_value; }
+
+  void add_set (const hb_set_t *set)
+  {
+    hb_codepoint_t i = HB_SET_VALUE_INVALID;
+    while (hb_set_next (set, &i)) add (i);
+  }
+
   /* Create an identity map. */
   bool identity (unsigned int size)
   {
@@ -138,6 +158,9 @@ struct hb_inc_bimap_t : hb_bimap_t
     for (hb_codepoint_t rhs = 0; rhs < count; rhs++)
       set (work[rhs], rhs);
   }
+
+  protected:
+  unsigned int	next_value;
 };
 
 #endif /* HB_BIMAP_HH */
diff --git a/src/hb-ot-layout-common.hh b/src/hb-ot-layout-common.hh
index 7082f08b8..ba4cca8a9 100644
--- a/src/hb-ot-layout-common.hh
+++ b/src/hb-ot-layout-common.hh
@@ -1786,13 +1786,13 @@ struct VarData
 
   bool serialize (hb_serialize_context_t *c,
 		  const VarData *src,
-		  const hb_bimap_t &inner_map,
+		  const hb_inc_bimap_t &inner_map,
 		  const hb_bimap_t &region_map)
   {
     TRACE_SERIALIZE (this);
     if (unlikely (!c->extend_min (*this))) return_trace (false);
-    itemCount = inner_map.get_population ();
-    
+    itemCount = inner_map.get_next_value ();
+
     /* Optimize short count */
     unsigned short ri_count = src->regionIndices.len;
     enum delta_size_t { kZero=0, kByte, kShort };
@@ -1805,7 +1805,7 @@ struct VarData
     for (r = 0; r < ri_count; r++)
     {
       delta_sz[r] = kZero;
-      for (unsigned int i = 0; i < inner_map.get_population (); i++)
+      for (unsigned int i = 0; i < inner_map.get_next_value (); i++)
       {
 	unsigned int old = inner_map.backward (i);
 	int16_t delta = src->get_item_delta (old, r);
@@ -1849,13 +1849,13 @@ struct VarData
     return_trace (true);
   }
 
-  void collect_region_refs (hb_inc_bimap_t &region_map, const hb_bimap_t &inner_map) const
+  void collect_region_refs (hb_inc_bimap_t &region_map, const hb_inc_bimap_t &inner_map) const
   {
     for (unsigned int r = 0; r < regionIndices.len; r++)
     {
       unsigned int region = regionIndices[r];
       if (region_map.has (region)) continue;
-      for (unsigned int i = 0; i < inner_map.get_population (); i++)
+      for (unsigned int i = 0; i < inner_map.get_next_value (); i++)
 	if (get_item_delta (inner_map.backward (i), r) != 0)
 	{
 	  region_map.add (region);
@@ -1939,7 +1939,7 @@ struct VariationStore
 
   bool serialize (hb_serialize_context_t *c,
 		  const VariationStore *src,
-  		  const hb_array_t <hb_bimap_t> &inner_maps)
+  		  const hb_array_t <hb_inc_bimap_t> &inner_maps)
   {
     TRACE_SERIALIZE (this);
     unsigned int set_count = 0;