From 30c42b644eb33551aa0986287182a46f2d8c32ed Mon Sep 17 00:00:00 2001
From: Behdad Esfahbod <behdad@behdad.org>
Date: Sat, 10 Sep 2016 03:32:39 -0700
Subject: [PATCH] [GX] Add hb_ot_layout_table_find_feature_variations()

---
 src/hb-ot-layout-common-private.hh   | 18 +++++++++++-------
 src/hb-ot-layout-gsubgpos-private.hh |  6 +++---
 src/hb-ot-layout.cc                  | 15 +++++++++++++++
 src/hb-ot-layout.h                   | 10 ++++++++++
 4 files changed, 39 insertions(+), 10 deletions(-)

diff --git a/src/hb-ot-layout-common-private.hh b/src/hb-ot-layout-common-private.hh
index 3c574af70..e67a5145d 100644
--- a/src/hb-ot-layout-common-private.hh
+++ b/src/hb-ot-layout-common-private.hh
@@ -1342,7 +1342,7 @@ struct ConditionFormat1
   friend struct Condition;
 
   private:
-  inline bool evaluate (int *coords, unsigned int coord_len) const
+  inline bool evaluate (const int *coords, unsigned int coord_len) const
   {
     int coord = axisIndex < coord_len ? coords[axisIndex] : 0;
     return filterRangeMinValue <= coord && coord <= filterRangeMaxValue;
@@ -1365,7 +1365,7 @@ struct ConditionFormat1
 
 struct Condition
 {
-  inline bool evaluate (int *coords, unsigned int coord_len) const
+  inline bool evaluate (const int *coords, unsigned int coord_len) const
   {
     switch (u.format) {
     case 1: return u.format1.evaluate (coords, coord_len);
@@ -1394,7 +1394,7 @@ struct Condition
 
 struct ConditionSet
 {
-  inline bool evaluate (int *coords, unsigned int coord_len) const
+  inline bool evaluate (const int *coords, unsigned int coord_len) const
   {
     unsigned int count = conditions.len;
     for (unsigned int i = 0; i < count; i++)
@@ -1470,17 +1470,21 @@ struct FeatureVariationRecord
 
 struct FeatureVariations
 {
-  inline const FeatureTableSubstitution &
-	       get_substitutions (int *coords, unsigned int coord_len) const
+  inline bool find_index (const int *coords, unsigned int coord_len,
+			  unsigned int *index) const
   {
     unsigned int count = varRecords.len;
     for (unsigned int i = 0; i < count; i++)
     {
       const FeatureVariationRecord &record = varRecords.array[i];
       if ((this+record.conditions).evaluate (coords, coord_len))
-        return (this+record.substitutions);
+      {
+	*index = i;
+	return true;
+      }
     }
-    return Null(FeatureTableSubstitution);
+    *index = 0xFFFFFFFF;
+    return false;
   }
 
   inline bool sanitize (hb_sanitize_context_t *c) const
diff --git a/src/hb-ot-layout-gsubgpos-private.hh b/src/hb-ot-layout-gsubgpos-private.hh
index 490b91e1b..e20777acb 100644
--- a/src/hb-ot-layout-gsubgpos-private.hh
+++ b/src/hb-ot-layout-gsubgpos-private.hh
@@ -2271,10 +2271,10 @@ struct GSUBGPOS
   inline const Lookup& get_lookup (unsigned int i) const
   { return (this+lookupList)[i]; }
 
-  inline const FeatureTableSubstitution &
-	       get_feature_substitutions (int *coords, unsigned int coord_len) const
+  inline bool find_variations_index (const int *coords, unsigned int num_coords,
+				     unsigned int *index) const
   { return (version.to_int () >= 0x00010001u ? this+featureVars : Null(FeatureVariations))
-	   .get_substitutions (coords, coord_len); }
+	   .find_index (coords, num_coords, index); }
 
   inline bool sanitize (hb_sanitize_context_t *c) const
   {
diff --git a/src/hb-ot-layout.cc b/src/hb-ot-layout.cc
index 0501181a3..b352cdb5d 100644
--- a/src/hb-ot-layout.cc
+++ b/src/hb-ot-layout.cc
@@ -836,6 +836,21 @@ hb_ot_layout_lookup_collect_glyphs (hb_face_t    *face,
 }
 
 
+/* Variations support */
+
+hb_bool_t
+hb_ot_layout_table_find_feature_variations (hb_face_t    *face,
+					    hb_tag_t      table_tag,
+					    const int    *coords,
+					    unsigned int  num_coords,
+					    unsigned int *variations_index /* out */)
+{
+  const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
+
+  return g.find_variations_index (coords, num_coords, variations_index);
+}
+
+
 /*
  * OT::GSUB
  */
diff --git a/src/hb-ot-layout.h b/src/hb-ot-layout.h
index eb23d45b6..2e3db8c20 100644
--- a/src/hb-ot-layout.h
+++ b/src/hb-ot-layout.h
@@ -95,6 +95,7 @@ hb_ot_layout_get_ligature_carets (hb_font_t      *font,
 #define HB_OT_LAYOUT_NO_SCRIPT_INDEX		0xFFFFu
 #define HB_OT_LAYOUT_NO_FEATURE_INDEX		0xFFFFu
 #define HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX	0xFFFFu
+#define HB_OT_LAYOUT_NO_VARIATIONS_INDEX	0xFFFFFFFFu
 
 HB_EXTERN unsigned int
 hb_ot_layout_table_get_script_tags (hb_face_t    *face,
@@ -236,6 +237,15 @@ Xhb_ot_layout_lookup_enumerate_sequences (hb_face_t    *face,
 					 void         *user_data);
 #endif
 
+/* Variations support */
+
+HB_EXTERN hb_bool_t
+hb_ot_layout_table_find_feature_variations (hb_face_t    *face,
+					    hb_tag_t      table_tag,
+					    const int    *coords,
+					    unsigned int  num_coords,
+					    unsigned int *variations_index /* out */);
+
 
 /*
  * GSUB